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HibrartPB 

of 


Vook 


£68,45 

WITHDRAW! 


From  the  collection  of  the 
3  f  d 

•n 

m. 

o  Prelinger 
v    Jjibrary 


San  Francisco,  California 
2007 


JULY 
1946 

35c 


To 


fr-fif/m 


accompaniment 

.the  PLAYANO  renders  enjoyable  "one-finger"  performances! 


Those  who  are  fond  of  music  .  . .  and 
yet  shy  away  from  the  piano  through 
an  inability  to  make  their  ten  fingers 
perform  .  .  .  will  welcome  Playano! 
Easily  positioned  over  the  standard 
keyboard,  it  converts  a  simply  num- 
bered, one-finger  technique  into  strik- 
ing a  series  of  harmonically  related 
chords. 

Those  who  love  and  admire  nice  things 
will  be  further  appealed  to  by  Playano's 
beauty.  Exquisitely  encased  of  Catalin, 
the  gem  of  plastics,  Playano  is  har- 
monious outwardly  as  well  as  inwardly 


—  And,  should  one  be  intrigued  to 
discover  "what  makes  Playano  play", 
we  might  add  that  the  key  tabs  and 
concealed  striker  action  were  molded 
of  lightweight,  dimensionally  stable 
Loalin  . . .  Catalin's  polystyrene  mold- 
ing compound. 

Catalin's  rich  colors  —  its  beauty,  bril- 
liance and  physical  properties  —  all 
offer  much  to  product  designers.  Cast- 
ing techniques,  too,  now  so  highly 
developed,  encourage  the  planning  of 
intricate  custom  shapes  without  the 
need  for  expensive  and  time-delaying 


molds.  Members  of  our  service  staff  will 
be  glad  to  discuss  these  and  other  Catalin 
advantages  with  you.  Inquiries  invited! 

CATALIN     CORPORATION 

1    PARK   AVENUE.  NEW    YORK    16.  N.  Y. 

Cntlill:  Van  Dyke  Hill,  luttnter;  Miuncc  A.  Lichicn, 
Inc..  F**ri<*tm  *iJ  MtUm:  Chic«*o  Mu«ic«l  Insiru. 
mem  Co.tlntfm^ttm^i  Dtitnliittn. 


CAST    RESINS    •     LIQUID    RESINS     •     M  0  L  D  I  N  6    COMPOUNDS 


YOUR      INJECTION 


WILL    LOWER 
MOLPING     COS'S! 


The  new  16  ounce  H-P-M  injection  mold- 
ing machine,  displayed  at  the  recent  Detroit 
and  New  York  plastics  expositions,  incor- 
porated many  new,  outstanding  production 
features,  some  of  which  are  reviewed  be- 
low. 

The  H-P-M  straight  line  hydraulic  mold 
clamp  provides  for  accurate  mold  align- 
ment, rapid  die  change-over,  positive 
overload  protection  and  many  other  fea- 
tures. The  newly  designed  material  heat- 
ing chamber,  equipped  with  electric  band 
heaters,  guarantees  ample  plasticizing 
capacity  with  accurate  zone  heat  control. 

Powered  by  the  reliable  H-P-M  oil- 
hydraulic  operating  system,  each  pump, 
valve,  and  control  is  designed  and  built 
by  H-P-M,  thus  guaranteeing  undivided 
responsibility  to  the  user. 

H-P-M  also  builds  4  and  9  ounce  capac- 
ity injection  units  for  high  speed  produc- 
tion of  smaller  parts.  All  sizes  of  machines 
are  being  built  in  stock  quantities.  Write 
today,  stating  your  requirements. 

THE    HYDRAULIC    PRESS    MFG.  CO. 

Mount    Gilcad,   Ohio,  U.  S.  A. 

tKANCH    OFFIdS    IN    NIW    YOKK,    PH  1 1 ADE  LPH  I  A, 

CLCVCIAND,   CINCINNATI,   DfT/fOIT  AND  CHICAGO. 

Represenfafivej    in    other   principal   cifies. 


Above  U  illustrated  a  16  ounce  "shot" 
having  a  projected  area  of  1 1 6  square 
Inches.  Minimum  production  cycle — 30 
seconds. 


Pfattic* 

MOLDING  PRESSES 


WITH          H  Y  D  P  A  1 1  I    I  <~  S          SINCE          1877 


JULY,    1946 


plastics 


in  this  issue 


"•ir<-« <-  Color 21 

<  :<mt..iner  Fabrication,  Part  II Mel  W<  v<  rs  26 

Teflon   Makes   Its   Debut 32 

Coating  Refrigerator  Shelve* Gerald  Eldridpe  Siedman  37 

\\  ..nin-   \  .-r-.itility  into  Fabrics William  Schai-k  I  i 

Know  Your  Melamines 44 

Admiral  Use*  More  I'l  ,-ii,  - V.  E.  Gibbvnx  48 

Injection  Mold  Deaign,  Part  III John  G.  Robb  52 

Building  Better  Kitchen  Accessories W.  (.hnrrh  58 

Patents  for  the  Asking 62 

An  Interpretative  Survey  of  German  Plantii-s  Fabrication.  Part    l\ 

'. W.C.  Goggin  64 

Properties   of   (-ore    Materials 

Benjamin  M.  Axilrod  and  Evelyn  Koenig  68 

New  Beauty  in   Fabrics 78 

A  New  Acrylic 84 

departments 

i'l«»tio    in    Perspective 18        Indu-tr>   Highlights  82 

On  the  Drafting  Board 43       What's  New  in  Plastic* 85 

1'lii.tiri.  at   Work 60       Literature   Review 88 

Suiintiral    Dala     79       People    89 

Knginerring    New.    Letter 80        Association   Activities    90 

Problem*    in    Plastic*. .  ,91 


COPYRIGHT,   1946 


ZIFF-DAVIS  PUBLISHING  COMPANY 


Editorial  Offic*t,    IS5  N.   Wabath   Ave.,   Chicago    I, 


WILLIAM  B.  Zirr 
fnblislitr 


B.  O.   DAVIS 

tifnrral   Manager 

HERMAN    R.    BOLLIN 
Art  Director 

H.  G.  STRONG 

Circulation   Director 


C.   R.    TIGHE 
All't.  to  Publisher 

GEORGE  BERNER 
Advertising  Director 

H.    I.    MORGANROTH 
Production   Director 


VOLUME  5,  NUMBER  1 


MICHAEL    H.    FROEUCH 

Editor 

WILLIAM  SCHACE 

Field  Editor 

V.  E.  GIBBENS 
Associate  Editor 

M.  CHURCH 
Associate  Editor 
ULA  SHATTER 
Associate  Editor 


GAITHER 
If  ',  st  Coast  Editor 

FRED  H  AMUN 
Washington  Editor 

CHARLES  A.  SCOGLAND 

Consulting  Technical  Editor 

WALTER  STEIIfHARD 

Staff  Photographer 

ARTHUR   E.   HAOG 
Staff  Photographer 

SYDNEY   BARKER 

Art  Editor 

ADVERTISING 

JAMES    A.    CERBONE 
Eastern  Advertising  Manager 

HOY  E.  UNDER 
Midwest  Advertising  Manager 

WILLIAM  L.  prNNEY 

Western  Advertising  M.I 

IftANCH      OFflCtS 

NEW  YORK  (1) 

Empire  State  Blag..  Wl  74400 

LOS  ANGELES  (M) 

SIS  S.  Hill  St..  TVeker  9213 

WASHINGTON   (4) 

International  Bldi.,  EXEcnlit'r  2i02 

TORONTO 
21  King  Street.  East 


Audit  lurMu  of 
Circulttiofll 


COVER 

Versatile  round  and  rai 
tan  type  "Saran"  mono 
hlam«nl«.  In  Yartotu  col- 
on. U  shown  on  ipools 
ready  lor  the  laboratory 
tsttinq  (IM  "N»w  Beau- 
ty In  Fabrics"  paa*  71) 


Other  Ziff-Davit  Publicationi:  Flying,  Popular  Photography,  Radio  Newt,  Radio-Electronic  Engineering. 


•M4  IMMMr   W   tOI-DnU   1-uI.II.Mnc   r.«T,|«n».    1 119  North  W.hjmli  An..    Ollnwo    I,    III. 
liitMMTlV.001    Ml  C*n*dii.    13   !••«»•.   in  v>     In  nrUl*h  Kmrlr*.    IS   !•«!••.    f4.nn.     All 
M  MirM*.     MtfFM*  ••   •utwrvlirtlon    l«l»-»«    In   th*    IHrmnr   of  CtmiUUon.     PLAHTICa.    I 
Ol»  ftff  «a^»  J»Cll^gl».    IlllnoH.   »nd»r  iho   Art  of  M.nli    1.    1ST*.      Coriinbuun    «W« 


.11  I.Y  194( 


ST*KTS 


*/r« 


*«** 


Precision — exactness — minuteness- 
to-detail  are  all  synonyms  for  ac- 
curacy. Choose  whichever  word  you  will,  we  in 
the  plastics  business  know  that  the  primary 
requisites  for  a  perfect,  finished  article  are  ac- 
curate molds.  So,  here  at  General  Industries  high 
technical  skill  and  fine  machining  ability  go  into 
making  them.  This  extreme  care  pays  off  in  extra 
dividends  for  you — because  an  accurate  mold 
cuts  down  machining  operations,  assures  you 
quicker  delivery — and,  above  all,  guarantees  a 
positive  meeting  of  specifications. 


Then,  just  to  make  certain  you  receive  the 
finished  product  "just  the  way  you  want  it", 
we  maintain  a  series  of  constant  tests  and 
checks,  on  the  finished  part,  with  precision 
instruments. 

So  you  see,  from  the  time  you  come  in  to  consult 
us  about  your  product,  until  final  delivery  is 
made,  General  Industries  leaves  nothing  in  the 
plastics  molding  job  to  the  element  of  chance. 
There's  no  substitute  for  knowledge  and  experi- 
ence— both  of  which  are  here  at  your  disposal  on 
your  plastics  problems. 


GENERAL 

NDUSTRIES  co. 


D  E  P  T  .        f 


E  L  Y  R   I   A 


OHIO 


JULY  1946 


PLASTiCS 


DESIGNED  BY 

PLASTICS  ENGINEERS 

FOR  THE  PLASTICS 

INDUSTRY 


Wide  range  of  shapes  and  sizes . .  .  with   the 
new  DEFIANCE  Plastic  Preform  Press! 

High  speed  production. 

Greater  uniformity  of  weight  and  density... 
cutting  down  molding  rejects. 


[\X    Compact,  modern  design. 


Easy  to  clean  . . .  color  changes  can  be  made 
with  minimum  of  cleaning  time. 

Quick  adjustment  of  density  while  operating. 

Quick  adjustment  of  fill  while  machine  is  in 
operation. 

Can  use  multiple  dies. 

Punches  and  dies  can  be  quickly  changed  . . . 
machine  complete  with  variable  speed  drive 
and  clutch. 

Less  material  leakage  assures  greater  economy. 


All  lubricated  parts  enclosed  and  below  die 
surface,  thus  eliminating  preform  spoilage 
due  to  oil  contamination. 

Interchangeable  parts.   Precision  made. 


Write  for  latest  bulletins.  Defiance  Machine  Works,  Inc.,  Defiance,  Ohio. 

DEFIANCE 


PMST/C  P&FOR/M  PRfZS 


I»f..t*TI t  * 


JULY  1946 


sf 

* 


*»  Oi.' 


od  Numbers 


H 


%  /• 


-make  a  note  of  them!" 

The  wells  of  each  painted  calibration,  numeral  and 
character  are  deeply  depressed  —  sharp,  clear, 
clean-cut!  To  achieve  these  results,  Consolidated 
begins  by  engraving  the  scales  into  the  steel  hob. 
Then  when  the  cavities  are  hobbed  in  mild  steel, 
the  characters  are  raised  so  as  to  produce  a  mold- 
ing depth  sufficient  to  anchor  and  hold  the  paint  — 
permanently! 

Should  you  be  planning  dial  elements  —  identifi- 
cation knobs  —  or  any  plastic  part  incorporating 
calibration  —  we'd  like  you  to  know  that  our  way 
with  numbers  makes  them  stand  out  —  and  not 
rub  out!  Inquiries  invited. 

Consolidated 

MOLDED    PRODUCTS     Gvtpoteitio* 
|         309  CHERRY  STREET,  SCRANTON  2,  PA. 

&*<i«cJu4.       NEW  YORK    •    CHICAGO    •    DETROIT    •    BRIDGEPORT    •    CLEVELAND 


injection  molding 
compression  molding 
transfer  molding 


"TOUI  ILUENINl 
IN  FUSTIC' - 


/ 


JULY  1946 


PLASTICS 


In  plastic  molding 


MOLDED 
EXCELLENCE 


assures  beauty  more 
than  surface  deep! 

Poor  surface  is  only  one  of  the  major  troubles 
which  may  ruin  an  otherwise  perfect  molding  job. 
'!  hese  "quirk-"  are  many — ranging  from  pitting 
and  bli-ter-.  to  sticking  and  warping.. .are  brought 
about  by  a  multitude  of  conditions. 

Micn.-c.ipic  -crtitiny  would  reveal  such  imperfec- 
tion- penetrating  far  below  the  surface  or  finish. 
deUing  into  the  bod\  of  the  -trueture  itself.  That's 
why  experience  goes  a  long  way  in  plastic  molding 
to  obtain  proper  re.-ults  .  .  .  with  mold  making 
lending  toward  craftsmanship,  rather  than  a  mere 
mechanical  pha-r. 


WRITE  FOR  THIS 


INFO! 


M\(.K  M()I,I)I\(r  )X  ilh  a  background  of  some  lucnt\-~ix  year- 
in  serving  industry  offers  complete  collaboration  from  d 
•ml  blueprint  inception,  right  through  to  final  delivery.  For  a 
better,  closer  customer-molder  •nderstanding  of  pla.-tic  molding 
and  the  problems  involved,  an  eight-page  booklet  is  available  ,,n 
request.  A  general,  non-technical  treatise,  this  literature  offer* 
helpful  hints  and  possibilities  for  plastics  in  your  scheme  of 
things.  A  note  on  your  letterhead  will  bring  your  copy  promptly. 

MACK  >ioi  m\<,  <  o.   ixrT 


SALES 


RMATIVE   BROCHURE 


130    MAIN    STREET,    WAYNE,    NEW   JERSEY 

OFFICES       NEW     VO«K,    CHICAGO.     DETROIT.    I  N  D  I  A  N  A  PO  I  I  S.     iOSTON.     AND    ST.    tOUIS 


JULY 


PAPER 

c 

at  work    in  many    new  ways! 


In  many  essential  products  MOSINEE  papers 
now  take  the  place  of  critical  materials.  Out  of 
wartime  necessities  came  new  inventions,  new 
uses*  of  available  materials.  Technological 
advances  were  speeded  up.  Today,  the  bene- 
fits of  many  new  uses  of  materials  can  be  mul- 
tiplied for  peacetime  progress,  by  working 


together,  like  Americans,  to  make  the  most 
of  opportunities  . . .  for  the  good  of  everyone! 


-X-  Modern  industrial  papers,  custom-made  to  meet  specific 
requirements,  with  characteristics  scientifically  con- 
trolled in  the  MOSINEE  manner,  have  become  essentials 
as  product  parts  or  materials.  Paper  technicians  of 
MOSINEE  are  qualified  to  help  many  industries  make  the 
most  of  special  custom-made  papers. 


OSINEE 

MOSINEE  •  WISCONSIN 


PAPER 

MILLS 

COMPANY 


Please 


your  letter 
Attention 
Dtft.B." 


JULY  1946 


PLASTiCS 


For  Versatility  in  Plastic  Molding 

you  can  Depend  on  GRIGOLEIT 


For  19  years  we've  supplied  many  nationally 
prominent  manufacturers  with  parts  and  trim  for 
their  products.  The  veraatility  of  our  facilities  and 
our  molding  experience  enable  us  to  create  unusual 
design  or  standard  plastic  items. 
For  reasonably  early  availability,  we  offer  an  ex- 
tensive "standard"  line  of  handles,  knobs  and 
other  parts  for  stoves,  furniture  and  household 


appliances;  also  a  large  "stock"  line  of  closures 
for  foods,  drugs  and  cosmetics. 
We  also  maintain  a  complete  custom-molding  serv- 
ice in  thermo-plastic  and  thermo-setting  plastics. 
Operating  our  own  metal  and  tool  shops,  we  are 
able  to  insure  perfect  blending  of  plastics  and 
metal. 

Write  for  1946  Catalog 


THE    GRIGOLEIT    COMPANY 


746    E.    NORTH    STREET  DECATUR    8O,    ILLINOIS 

10  I'I..\STI1   *>  .HI.Y    1946 


"9? 4,   ZadleU   £+i(llza<j.ai   that  Make* 


a 


an 


d 


developed  QUA,  Skill  oW  Aiilify 

There  is  a  science  in  reclaiming  so-called  "waste"  and  residue  and  making  them 
practically  comparable  to  prime  powders.  It's  not  a  job  to  be  entrusted  to  the 
untried.  Repetition  and  intimate  knowledge  of  plastic  characteristics  have  en- 
abled us  to  perfect  methods  that  only  patient  and  persistent  research  could 
establish. 


We   pay   top   prices  for  Thermoplastic   Materials.     We   clean,   de- 
metalize,   grind   and    plasticize  them,   restoring   essential   vigor   and 


JULY  1946 


^Irlasterit  oj  ^Illciyic  in    (^licrinofjlastic  coni-crsi 

PLASTICS 


son 


11 


Manufacturers  of  hundreds  of  differ 
things  have  brought  their  spring  design 
problems  to  Accurate  engineers.  And, 
Accurate  engineers  have  been  able  to  design 
springs  that  were  exactly  right  for  the  jobs.  Often, 
their  suggestions  have  improved  product  performance, 
reduced  spring  costs  and  even  speeded  up  assembly  time. 

Could  you  use  practical  help  on  your  spring 
engineering  problems?  Would  you  benefit  by  the  services 
of  a  specialized  engineering  department  .  .  .  one  with  millions 
of  springs  of  experience?  Ask  an  Accurate  representative  to  call. 

ACCURATE  SPRING   MFG.  CO. 
3878  W.  Lake  Street 
Chicago  24,  Illinois 


12 


n..\sTii  * 


JULY   1946 


PLASTICS  VOCAL  CORDS  FOR  OUR   FLEET 


hen  her  big  guns  spoke,  a  warship's  loud-speaker  system 
didn't.  Gun  blast  was  too  much  for  the  loud-speaker  dia- 
phragms. They  failed  when  needed  most  for  battle  commands. 

This  naval  problem  was  brought  to  No.  1  Plastics  Avenue 
and  was  solved  by  General  Electric's  complete  plastics  service. 
General  Electric  engineers  developed  a  special  phenolic- 
treated  cloth  that  can  be  molded  as  thin  as  0.003  in.,  and 
drawn  to  domed  contours  of  acoustical  precision. 

These  plastics  diaphragms  can  take  it.  They  kept  on  speaking 
through  many  a  sea  battle.  And  these 
new  tough,  but  sensitive,  diaphragms 
can  keep  many  a  peacetime  loud- 
speaker on  the  job,  too. 

Cloth-based  plastics  can  be  precision- 
molded  in  many  forms  to  combine  thin- 
ness, strength,  and  flexibility.  If  you 
need  such  a  component,  or  any  other 
plastics  part,  see  G.  E.— the  world's 
largest  manufacturer  of  finished  plastics 


parts.  Plastics  Divisions,  Chemical  Department,  General 
Electric  Co.,  1  Plastics  Avenue,  Pittsfield,  Mass.  Send  for  a 
copy  of  the  new  illustrated  booklet,  "What  Are  Plastics?" 

G-E  Complete  Service  —  Everything  in  Plastics 

Backed  by  52  years  of  experience.  We've  been  designing  and  manu- 
facturing plastics  products  ever  since  1 894.  G-E  Research  works  continu- 
ally to  develop  new  materials,  new  processes,  new  applications. 

No.  1  Plastics  Avenue  — complete  plastics  service — engineering,  design 
and  mold-making.  Our  own  industrial  de- 
signers and  engineers,  working  together,  cre- 
ate plastics  parts  that  are  both  scientifically 
sound  and  good-looking.  Our  own  toolrooms 
are  manned  by  skilled  craftsmen — average 
precision  mold  experience,  12  years. 

All  types  of  plastics.  Facilities  for  com- 
pression, injection,  transfer  and  cold  molding 
.  .  .  for  both  high  and  low  pressure  laminat- 
ing ...  for  fabricating.  And  G-E  Quality 
Control — a  byword  in  industry — means  as 
many  as  160  inspections  and  analyses  for  a 
single  plastic  part. 


GENERAL  11  ELECTRIC 


General  Electric  plastics  factories  are  located  in  Fort  Wayne,  Ind.,  Meriden,  Conn.,  Scranton,  Pa.,  Taunton,  West  Lynn,  and  Pittsfield,  Mass. 

JULY  1946  PLASTtCS  13 


STOKES 


Preform  Presses 

• 

.  .  .  Choice  of  the  Plastics  Industry 

Since  Its  Beginning 


STOKES  Preform  Presses  are  preferred  equipment  in 
modern  molding  plants  They  meet  present-day  de- 
mands for  larger  preforms  ...  for  rugged  machines  that 
withstand  hard  service  in  long  production  runs  They  offer 
a  wide  choice  of  equipment  from  which  to  select  presses 
to  best  meet  individual  requirements. 
For  Large  Preforms  up  to  4"  dia  ,  the  heavy-duty  Stokes 
No.  280  is  recommended  ...  a  toggle-type  press,  with 
4"  die  fill,  applying  up  to  80  tons  pressure  Other  presses 
are  available  for  pressures  from  100  to  300  tons  capacity. 
For  Large  Output  use  a  Rotary  type  press  .  .  .  makes 
balls  or  standard  shapes  up  to  1  3  16"  dia.  at  300  to  350 
per  min.  We  build  eight  different  models  and  sizes  of  this 
type  press  with  output  up  to  1000  per  minute. 
For  General-Purpose  Pre/orming  we  offer  versatile  Single 
Punch  Presses,  readily  changed  from  one  job  to  another. 
Four  models.  The  "R"  machine  shown  has  2"  die  fill, 
makes  preforms  up  to  2l/z"  dia.  at  production  rates  up 
to  SO  per  minute. 

Stokes  Preform  Presses  are  rugged,  of  semi-steel  con- 
struction, with  working  parts  thoroughly  protected  from 
dust.  Equipped  with  Automatic  Excess  Pressure  Release, 
to  prevent  jamming.  Easily  adjusted  lor  preform  hardness 
and  weight. 

F.     J.     STOKES     MACHINE     CO. 
6040  Tabor  Road  Philadelphia  20,  Pa. 


For  complete  description  ol 
above  and  other  Stokes  Presses, 
write  lor  copy  ol  Molding  Cata- 
log No.  427  —  showing  illustra- 
tions and  specifications  on  ten 
popular  models  ol  single  punch 
and  rotary  type  preform  presses 


- 


GENERAL  PURPOSE 


HIGH  PRODUCTION 


HEAVY  DUTY 


AUTOMATIC 
TABLETTINO   EQUIPMENT 


14 


n  I.Y  19 


" 


CONTINUOUS  EXTRUSION 
PLUS  FABRICATIO 


Patent  Pending 


Distributed  exclusively 
the 
tion, 


L-v  ^_      L_  ^L  Distributed  exclusi 

\  ^P     /  ^^  in  the  U.  S.  A.  by 

\                ^L/  f  Udylile      Corporal 

\               ^tf  f  Detroit. 

4J.ARD 


Here's  another  Yardley  develop- 
ment that  saves  time  and  cuts  costs. 
These  plastic  floats  for  plating 
tanks  are  extruded,  sealed  and  cut 
in  a  single  continuous  operation. 

Let  Yardley  engineers  study  your 
needs  and  products.  Chances  are 
they  can  suggest  similar  production 
improvements  that  eliminate  extra 
fabrication  steps. 


L  E  Y 


-a. 


142  PARSONS  AVE.  COlUMtUS   JS.  OHIO 

I.»r.a.r,   «   SA.AN.   CCUUIOU  ACITATt.   10TY«A«.  fOlYSTYKINf.  STYHALIOY  «,rf  VINYIS.  A.,.  !«(««.,   md  C.«,p,  «,to«   M.,—  , 


[ULY  1946 


PLASTICS 


15 


dustrial 


ngineers 


• 


New  thermoplastic  molding  mate- 

rials offer  unique  combination  of 
properties  which  may  be  precisely 
right    for    your    parts    or    products. 

Tough    and    durable  —  with    hard 
permanent  finish  which  requires  no 

polishing  or  corrosion-proof  coat- 
ing. they  add  years  of  service  — 
save  you  time  and  money! 

Universal's  design  and  engineering 
department  is  ready  now  to  trans- 
late your  specifications  into  prod- 

ucts that  do  your  job  better.  With- 
out obligation,  write  or  wire  today. 


A        •         1C 


%       • 


•   c 


CORPORA 


•  o  w 


270     MADISON    AVENUE         •         NEW    YORK     16,    N  .    Y. 
PHONE:     MURRAY    HILL    5-3950       •       PLANT;    NEW     BRUNSWICK.     N.    J. 
16  !•  LAST  11  •* 


Jl'LY   1916 


SEAL . . .  PREHEAT. . .  BOND 


SEALERS: 

No  more  stitching  or  sealing  of  fabricated  plastic  products 
by  means  of  obsolete  adhesive  or  resistance-heating 
methods!  THERMATRON  seals  by  radio-frequency  heat, 
cuts  production  time  to  seconds  .  .  .  gives  water  and  air- 
tight tenacious  seams  that  are  stronger  than  the  thermo- 
plastic itself!  Hundreds  of  products  are  now  being  Therma- 
tronically  sealed,  automatically,  by  unskilled  operators. 
There  is  a  THERMATRON  for  every  thermoplastic  sealing 
job.  Convince  yourself!  Write  NOW  for  complete  FREE  data. 


HEATERS: 


Lower  costs,  eliminate  rejects  and  increase  preform  out- 
put with  the  THERMATRON  Heatmaster,  the  all-purpose 
high-frequency  pre-heater  for  the  plastics  industry.  It  gives 
automatic  and  continuous  uniform  preheating  at  such 
speeds  as  90  seconds  for  a  5  Ib.  charge  heated  to  270'  F. 
Thermatronic  heating  prolongs  mold  life,  assures  better 
cure,  less  internal  stress,  uniform  density  and  high  gloss 
without  blistering  or  flow  marks.  Safe/automatic  operation 
protects  personnel. 

For  more  information  write  on  your  letterhead  for  a  copy  of  the 
booklet  "Electronic  Heating  with  THERMATRON"  today)  Address 
Dept.  T.  1 


THERMATRON     DIVISION 


ItADIO  RECEPTOR  COMPANY,  Inc. 

ft! 


251    WEST   19TH  STREET 


Since   1922  in  Radio  and  E/eclronics 

Chicago  Soles  Agent: 
Zephyr  Electronics,  5818  Wenlworth  Avc.,  Chicago,  III. 


NEW   YORK   11.   N.  V 
*Reg.  Trade  Mark 


ULY  1946 


PLASTICS 


17 


PLASTICS 


A  CHALLENGE  to  American  inventors  and  mechanical 
engineers  to  develop  better  artificial  limbs  was  re- 
cently issued  by  L)r.  Paul  E.  Klopsteg,  Chairman  of  the 
Committee  on  Prosthetic  Devices,  through  the  facilities 
of  the  National  Inventors  Council,  Department  of  Com- 
merce. 

Stressing  the  urgent  needs  of  17,000  war  amputees 
and  an  estimated  annual  minimum  of  25,000  civilian 
amputees,  Dr.  Klopsteg  urged  that  ideas  and  sugges- 
tions for  better  prosthetic  devices  be  submitted  to  NIC 
for  analysis  and  screening. 

Among  the  pressing  problems  requiring  solution  are : 
the  development  of  ( 1 )  improved  joint  mechanisms,  of 
which  knee  and  hand  mechanisms  present  the  most  for- 
midable problem  ;  (2)  lighter  materials ;  (3)  new  fabri- 
cation methods ;  and  (4)  improved  fitting  procedures 
and  techniques  for  describing  and  teaching  these  pro- 
cedure- \l-n  urgently  needed  is  further  fundamental 
study,  of  which  there  has  been  surprisingly  little,  of  the 
mechanics  of  human  motion. 

Although  most  of  these  problems  are  currently  the 
subject  of  private,  as  well  as  public,  research,  progress 
would  naturally  be  much  faster  with  the  application  of 
inure  research  time  and  more  talent  to  the  development 
of  improved  devices.  Maybe  there  is  an  opportunity 
for  plastics  here.  Certainly,  plastics  meets  the  requisite 
of  light  weight,  it  offers  new  possibilities  in  fabrication 
methods,  and  in  some  laminated  forms  it  represents  a 
distinct'advance  in  dimensional  stability  over  previous 
materials.  I  As  a  matter  of  fact,  laminated  plastics  are 
now  being  tested,  though  it  is  assumed  that  much  of  the 
development  work  remains  to  be  done. ) 

Here  is  a  challenge  which  deserves  the  industry's  con- 
sideration. 

*     *     * 

WITH  the  war  some  months  over  and  labor  show- 
ing promise  of  becoming  increasingly  available 
even  in  the  lower  wage  brackets,  it  is  time  to  give  in- 
creased thought  to  the  matter  of  housekeeping,  often 
neglected  during  the  war.  Some  of  the  plants  we  have 
visited  in  recent  weeks,  plastics  as  well  as  non-plastics, 
have  been  untidy,  dirty,  messy,  and  unnecessarily  clut- 
tered. \Vc  should  expect  prospective  customers  to  look 
askance  at  such  disarray.  They  might  be  expected  to 
wonder  about  the  correlation  between  the  appearance  of 
the  plant  and  the  quality  of  product  manufactured  in  it. 
To  illustrate,  suppose  a  prospective  cu-tomer  had 
narrowed  his  choice  for  a  si/cable  contract  down  to  two 
molders,  and  to  aid  in  making  a  final  choice,  he  decided 
to  visit  their  plants.  I  It-  found  <>m-  plant  dirty,  the  other 
-pick  and  span.  U  then-  any  doubt,  other  conditions 
l>cing  equal,  how  he  would  choose  • 


Apart  from  other  considerations,  the  indu.-try  >hould 
pick  up  the  broom  and  give  itself  the  once-over  because 
good  housekeeping  is  good  business. 


IN  A  story  in  a  recent  issue  of  a  national  magazine,  the 
sleuths  assigned  to  a  murder  case  were  baffled  in 
their  search  for  the  murder  weapon.  None  of  the  -i\ 
persons  in  the  room  at  the  time  of  the  killing  had  had 
an  opportunity  to  dis]x»se  of  it,  however,  and  so  it  had 
to  be  present.  The  only  find  -and  that  hardly  appeared 
to  be  a  clue — was  a  cheap  ash  tray  in  an  otherwise 
sumptuously- furnished  room. 

It  is  eventually  revealed  that,  preceding  the  crime,  the 
ash  tray  had  been  molded  into  a  dagger.  After  stali- 
bing  the  victim,  the  killer  plunged  the  dagger  into  a  pot 
uf  hniling  water  from  which  the  murdered  man  had 
been  making  tea,  and  the  dagger  reverted  to  its  original 
shape  as  an  ash  tray.  This  unassisted  metamorphosis 
was  explained  by  the  "elastic  memory"  of  the  plastic-. 
The  dagger  made  such  a  good  ash  tray  out  of  itself  that 
the  private  "eye"  who  solved  the  case  couldn't  tell  by 
looking  at  it  that  it  wasn't  a  conventional  dime-store 
glass  ash  tray. 

This  represents  the  type  of  publicity  that  so.  often 
leads  to  erroneous  ideas  about  plastics  in  the  minds  uf 
the  public.  The  industry  cannot  do  much  to  combat  this 
sort  of  thing  except  always  to  be  sure  in  making  claims 
for  its  materials  that  it  also  state  clearly  their  limitations. 
That  its  own  welfare  iK-lumve-  it  to  do. 


THE  recent  La  Salle  Hotel  holocaust  in  Chicago  with 
a  death  toll  which  at  last  re]x>rt  had  reached  61  and 
the  Canfield  Hotel  fire  in  Dubuque  with  its  19  victims 
burned  and  suffocated  to  death  grimly  emphasize  what 
we  said  a  few  months  ago  about  the  destructiveness  of 
fire  and  the  need  for  fireproof  building  materials,  instal- 
lations, and  furnishings.  At  the  risk  of  harping  on  the 
same  subject,  we  should  like  to  point  out  again  to  tin- 
industry  that  a  priceless  opportunity  awaits  the  develop- 
ment of  improved  fire-resistant  building  materials  and 
furnishings  at  a  cost  which  would  put  them  within 
reach  of  the  masses  of  u-. 

Some  of  these  days  people  are  going  to  awake  to  the 
fact  that  fires  are  not  something  they  have  to  put  up  with 
like  the  wind  and  the  lightning,  and  they  are  going  to 
demand  non-flammable  paneling,  furniture,  drapes,  and 
other  safer  materials.  When  that  time  conies,  some  in- 
dustry or  industries  will  come  up  with  the  answer.  We 
think  it  might  be  the  plastics  industry  if  the  proper  effort 
is  expended  in  that  direction.  END 


I'L.iSTH  '* 


JULY  Ittifi 


Easy  Does  It.. 


Try  the  Easy  touch   for  better  results  in  Plastics  ! 


I  adds  up  very  simply.  Cut  the 

nolding  pressures  way  down,  and 
•our  piece  naturally  comes  out  bet- 
er  in  every  way — stronger,  more 
horoughly  cured,  possessing  better 
inish,  more  uniform  density  and  a 
ligher  effectiveness  of  properties.  It 
vill  have  minimized  internal  stress 
,nd  no  weld  lines.  And  your  mold 
vill  give  much  longer  service  be- 
ore  showing  wear. 

How  to  do  it?  Heatronics  is  the 
.nswer — radiofrequency  pre-heat- 
ngof  plastic  pre-forms— a  molding 


technique  that  permits  lower  mold- 
ing pressures  by  increasing  the 
plasticity  and  ease  of  flow  of  mold- 
ing materials. 


Plastic  Pre-Jorm  in  Heatronic  Applicator 


The  only  catch  is  that  Heatronic 
equipment  isn't  easily  acquired  even 
now— nor  is  experience  in  its  use 
picked  up  overnight.  Generally, 
that  is.  But  it's  different  at  Jturz- 
Kasch.  We  pioneered  in  applying 
Heatronics  to  plastics.  Our  Heat- 
ronics installation— and  our  knowl- 
edge of  its  use — balances  our  exten- 
sive custom  molding  facilities. 

Is  there  something  you'd  like  to 
know  about  Heatronics  applied  to 
compression  or  transfer  molding? 
Just  ask  for  a  Kurz-Kasch  engineer. 


Kurz-Kasch 


For  Over  29  Years 

Planners  and  Molders  in  Plastics 


ULY  1946 


Kurz-Kosch,  Inc.,   1413  S.  Broadway,  Dayton   1,  Ohio.     Export  Offices:   89  Broad  Street,  New  York,  New  York. 
Branch  Safe*   OHicms:   New   York  •   Chicago   •    Detroit  •   Los  Angeles   •   Dallas   •   St.  Louis   •   Toronto,  Canada. 

PLASTtCS 


19 


; 


rot.m 
Appl,«d  (o. 


RIGHT! 

. .  .  and  Helped  a 
Customer  Expand 
Sales  Opportunity 
with  this  . 


ised' 


lOt   (LtCrilCAl  ArPLlJUICU 


OMICI  MACniHti  01  intgmiAi  igvinmr 


ei«o»n«'  -\. 


The  customer  came  to  Amos  and  asked  this  question  .  .  .  "Can 
you  develop  a  hinge  that  will  enable  us  to  merchandise  and  sell  our 
plastic  picture  frames  as  doubles  and  triples  as  well  as  singles?" 

The  Amos  answer  to  that  question  is  shown  above — a  plastic 
hinge  that  snaps  on  and  holds  two  or  more  frames  securely.  The 
hinge  consists  of  only  two  plastic  pieces,  molded  eight  at  a  time 
and  quickly  assembled — no  metal  parts  or  rivets  required.  In- 
genious engineering  —  another  Amos  job  done  right  —  another 
customer  pleased! 

h 

Amos  ability  and  facilities  can  be  helpful  to  you  in  the  design 
and  production  of  any  practical  plastic  application  that  can  be 
injection  molded — whether  it  be  a  small  product  part  or  a  com- 
plete unit.  And  your  Amos  job  will  he  done  right — from  engineer- 
ing to  molding  to  finishing.  Just  send  us  your  drawings,  or  write 
us  what  you  have  in  mind. 

AMOS    MOLDED    PLASTICS,    EDINBURGH,    INDIANA 

DMiion  of  AmoxTtiompton  Corporation 
On*  of  NX  Mart  Modern  Pls.tic  Molding  Planli  in  Iht  Induftrf 


20 


JULY   1946 


Numerous  plastics  articles 
now  crowding  the  shelves  of 
stationery  and  office  sup- 
ply stores  testify  to  the  at- 
tractive coloring,  pleasant 
feel,  light  weight,  and  dur- 
ability of  these  materials 


STATIONERY  DESIGN 


STRESSES  COLOR 

Introduced  as  a  war-time  measure,  plastics 
are  now  firmly  entrenched  in  the  manufacture  of  stationery  supplies 


ALMOST  everyone  acquainted  with  the  rapid  strides 
made  by  the  plastics  industry  is  aware  of  the  fact  that 
plastics  are  now  being  used  in  stationery  and  office  supply 
items.  But  the  great  extent  to  which  plastics  have  invaded 
this  market  may  not  be  so  well  known.  Although  some  of 
these  applications  are  substitute  measures  born  out  of  war- 
time shortages  of  critical  materials,  many  are  permanent 
and  will  remain  in  force.  It  is  the  purpose  of  this  article 
to  give  a  comprehensive  survey  of  this  market  for  plastics, 
discriminating  where  necessary  and  possible  between  per- 
manent and  temporary  uses. 

One  firm  which  has  introduced  plastics  into  this  field  and 


met  with  notable  success  is  the  Zephyr  American  Corp., 
New  York  City.  Using  a  urea  housing  molded  by  Mack 
Molding  Co.,  they  have  put  on  the  market  an  Autodex  tele- 
phone index  and  have  already  sold  several  million  of  them. 
The  index  is  designed  in  either  burgundy  or  brown  and  has 
a  sliding  name  locator  plus  a  push  button  cover  release 
which  brings  the  desired  phone  number  to  your  fingertips 
in  a  matter  of  seconds.  It  retails  for  $2.50. 

Zephyr  American's  other  plastics  product,  an  ingeniously 
designed  pen  and  inkwell  set  molded  by  Ardee  Plastics,  has 
three  parts  made  of  cellulose  acetate-butyrate — collar,  filling 
mechanism,  and  molded  pen,  the  well  proper  and  the  base 


JULY  1946 


PLASTICS 


21 


being  of  glas».  The  inkwell  combination  *wi\el*  in  all  di- 
rections to  accommodate  personal  preference  for  the  nio-t 
comfortable  writing  angle:  it  holds  mure  than  a  >ix  month-/ 
supply  of  ink.  which  can  not  dry  up  or  spill  out;  and  it  de- 
livers the  proper  amount  of  ink  to  the  pen  regardless  of  the 
ink  level  in  the  well.  The  set  retails  at  $3.00. 

The  Bert  M.  Morris  Co.,  I-os  Angeles,  is  another  manu- 
facturer of  plastics  inkwells.  One  of  their  products  is  a 
combination  pen  and  inkwell  mounted  on  a  3  by  5  memo 
pad,  the  entire  unit  being  molded  of  butyrate.  It  is  avail- 
able in  many  colors  to  harmonize  with  office  fittings  and  in 
decorative  pastels  for  the  home.  Goldsmith  Bros.,  one  of 
New  York's  largest  stationery  stores,  where  many  of  the 
items  mentioned  in  this  article  are  obtainable,  retails  this 
unit  for  $4.30.  There  seems  to  be  no  doubt  at  all  in  the 
minds  of  stationery  wholesalers  and  retailers  that  plastic* 
add  considerably  to  the  attrnctivenes*  and  utility  of  pen 
and  inkwell  sets  and  that  here  at  any  rate  is  an  application 
for  which  plastics  are  the  most  suitable  material. 

The  Morris  firm  also  makes  transparent  Tenite  II  covers 
for  typewriter  keys  which  are  advertised  as  sanitary  and 
ea-ily  cleaned  as  well  as  non-injurious  to  fingernails.  They 
also  protect  the  typist's  eyes  from  glare  and  reflected  light. 
Called  Kef  K&fers,  they  are  available  in  transparent  green 
for  ordinary  use  and  in  jet  black  for  touch  typing. 

Another  n*eful  typewriter  accessory  is  a  cellulose  ace- 
tate eraser  shield  made  by  T.  W.  Radel,  Newark,  to  provide 
clean  and  efficient  protection  for  carbon  copies  and  carbon 
paper.  Curved  to  conform  to  the  contour  of  the  typewriter 
roller,  'the  shield  is  placed  on  top  of  the  uncoated  surface  of 
the  carbon  paper  while  the  erasure  is  made  on  the  original. 
It  retails  for  35c  and  can  be  supplied  in  red,  mottled  blue, 
and  mottled  green. 


Calalin  cast  phenolics  are  also  well  represented  in  *ta- 
tionery  goods.  They  are  u-ed  for  pen  tapers,  paper  folders, 
automatic  pencils  for  bridge  scoring,  and  in  the  construction 
of  modestly  priced  as  well  as  high-priced  desk  sets.  Most 
of  these  articles  are  produced  from  standard  castings,  but 
one  device,  an  implement  for  fastening  *tickers  to  photo- 
graphs, is  made  from  a  special  casting.  For  novelty  pencil 
sharpeners  little  animal  shapes  produced  from  profile  cast- 
ings are  cut  to  desired  thickness,  drilled,  and  as>embled  with 
a  blade. 

An  excellent  example  of  the  virtue*  obtainable  with  a 
combination  of  plastics  and  fibrous  glass  is  the  Rusli-l;ybr- 
glass-Eraser,  which  has  a  butyrate  (Tenite  II)  case  molded 
by  Nosco  Plastics  and  an  eraser  composed  of  thousands  of  J 
finely  spun  glass  fibers  which  are  held  together  by  a  flexible 
binder.  This  can  be  projected  and  withdrawn  from  the 
barrel  by  a  screw  arrangement,  as  in  the  familiar  type  of 
pocket  pencil.  Only  a  few  light  brushing  strokes  are  needed 
to  erase  typewritten  originals — without  smudging  the  carbon 
copy  below.  In  addition  to  stenographers  and  typists,  it  is 
recommended  for  liookkeepers,  optometrists,  photographer*, 
printers,  jewelers,  and  electrical  workers  who  require  a  very 
fine  abrasive.  The  eraser  retails  for  50*. 

There  are  two  noteworthy  contributions  of  the  acrylic*  to 
office  desk  accessories.  One  is  a  completely  outfitted  de*k 
set  consisting  of  a  rocker  blotter,  inkwell  and  pen  rest  (the. 
well  itself  is  glass),  calendar  holder,  and  letter  opener, 
retailing  at  $14.95.  The  other  is  a  name-holder  with  back- 
rest, retailing  at  $4.95. 

For  the  modern  executive's  desk  there  are  two  plastic* 
accessorie*   for  the  telephone,  which  itself  is  usually  phe-  , 
nolic,  with  cellulose  acetate  promising  to  come  into  wider 
use.     One  is  a  phenolic-molded  noise  dampener.  called  a  ' 


Taub«r  Tub*  Binding  of  New  York  otters  colorful  bindings  of  cellulose  acetate  and  cellulose  acetate  butyrate 


Among  the  many  practical  and  attractive  plastics 
stationery  items  which  have  won  popular  approval 
are  these  "Autodex"  telephone  indexes  with  urea 
housings,  rocker  blotters  produced  of  phenolics, 
and  novelty  pencil  sharpeners  made  of  "Catalin" 


Hush-A-Phone,  which  clamps  on  to  the  speaking  end  of 
a  telephone  receiver.  It  provides  privacy  for  business  and 
personal  matters  and  makes  possible  the  elimination  of 
surrounding  office  noises,  so  that  they  are  not  transmitted 
over  the  line.  In  addition,  office  employes  will  not  be  dis- 
turbed by  the  clamor  of  loud  phone  talk. 

The  other  phone  accessory  is  the  familiar  No-Kink  cord 
holder,  made  usually  of  extruded  cellulose  acetate  and  oc- 
casionally of  butyrate,  which  winds  around  the  telephone 
'cord.  It  is  supplied  in  high  colors  serving  to  brighten  the 
drabness  of  the  dull  brown  cord.  It  also  serves  the  very 
important  purposes  of  protecting  the  cord  against  abrasion 
and  keeping  it  free  of  troublesome  tangles  and  snarls.  It  is 
useful  not  only  for  telephone  cord  but  also  protects  the  cord 
insulation  of  the  external  wiring  of  radios,  irons,  electric 
shavers,  and  other  appliances.  Retail  price  is  28tf. 

These  cord  holders  are  available  in  three  different  design. 
to  suit  individual  taste.  The  No.  30  model  is  a  spaced  coil, 
furnished  in  eight  different  colors ;  No.  35  is  a  double  coil 
or  Two-Tone  and  is  furnished  in  any  combination  of 
those  eight  colors.  According  to  Frank  Paper  Products, 
Detroit,  manufacturers  of  the  cord  holders,  No.  25,  which 
has  a  white  stripe  running  through  a  black  closed  coil,  is  a 
brand  new  development  unlike  anything  on  the  market 
today. 

Busy  executives  in  need  of  a  tiling  device  which  may  be 
kept  close  at  hand  will  find  the  Rcdi-Record  unitizer  of 
service.  Its  leaves  are  indexed  with  Mak-Ur-Own  Cel- 
luloid tabs  made  by  the  Victor  Safe  &  Equipment  Co., 
and  it  is  bound  with  cellulose  acetate  Multi-Ring  coils,  made 
by  Tauber  Tube  Binding,  New  York  City.  The  unitizer 
retails  for  $3.47. 

Mak-Ur-Oum  tabs,  furnished  in  seven  different  colors 
and  in  widths  of  J4",  -^",  and  y2",  are  cut  to  desired  size 
for  office  files  by  the  typist  from  6"  long  strips.  Thus  any 


JULY  1946 


23 


A  deik  set  of  acrylics  add*  a  lovely  note  to  the 
desk,  whether  it  be  in  the  home  or  in  the  oHice 


The  Bert  M.  Morris  Co.,  Los  Angeles,  offers  a  combi- 
nation inkwell  and  memo  sheet  holder  of  "Tenite  II" 


Thousands    of    finely    spun    glass    fibers    in    'Tenite 
II"    housing    produce    efficient    quick-acting    eraser 


Another    popular  selling    plastics    stationery    item 
is  T.  W    Radel's  cellulose  acetate  eraser   shield 


>izc  tab  up  to  6"  long  can  be  made  to  fit  the  index  label, 
eliminating  waste  and  crowding.  The  tabs  are  made  of 
heavy  gauge  Celluloid  and  closely  woven,  flexible  gummed 
linen  skirts  which  adhere  instantly  and  permanently.  The 
headed  outer  edge  of  the  tab  holds  the  insertable  index  labels 
securely  in  place.  The  fold  in  the  skirts  forms  a  positive 
guide,  which  assures  uniform  exposure  of  all  tabs.  Two 
six-inch  strips  in  any  width  together  with  blank  index  labels 
retail  for  30<.  Cellulose  acetate  is  also  commonly  used  for 
making  index  tali*. 

Plastics  bindings — usually  either  cellulose  acetate  or  cel- 
lulose acctobutyrate — have  the  advantages  of  high  color, 
plea-ant  feel,  and  light  weight.  According  to  Tauber  Tube 
Binding,  a  firm  that  used  plastics  for  bindings  even  before 
the  war  and  which  in  no  way  regards  them  as  a  substitute 
material,  plastic-  bindings  can  be  used  effectively  and  eco- 
nomically for  all  kinds  of  printed  matter,  including  liooklets. 
catalogs,  swatch  luniks,  calendars,  check  books,  sample 
books,  etc. 

In  the  operation  of  inserting  the  bindings  into  punched 
slots  in  the  books,  plastics  also  offer  certain  advantages 
According  to  Tanlx-r  Tube  Binding,  the  tul*  type  of  binding 
is  quickly  inserted  into  punched  slots  by  slight  finger  pres- 
sure, and  in  their  plant  one  girl  closes  500  tubes  per  hour. 
Their  Hfulti-Ring  coil  bindings,  are  inserted  by  placing  one 
end  of  thr  coil  into  the  punched  slot  and  then  spinning  the 
rot  of  it  into  place.  In  the  insertion  operation  the  resil 
iency  of  the  plastics  reduces  the  tendency  to  grab  and  tear 
the  paper  which  is  characteristic  of  metal  wire.  The  resil 
iency  also  provides  for  restoration  of  the  original  shape 
(Continued  on  pagr  '"J  i 


I'l.  ASTU  * 


JULY   194R 


' 


V 


f  hiph-i-htiir  lm\\  ami  it-beets  nrt>  nutlttiil  by 


New  High  for  Tenite 


Lightweight,  lustrous  Tenite  forms  tray 
ancl  tray  arms  of  this  new  high  chair 
which  converts  to  a  low  play  table  and 
chair  resting  on  small  Tenite  wheels.  No 
amount  of  hanging  with  baby  cups  or 
spoons  can  dent  the  tough  Tenite,  and 
its  color  and  finish  will  remain  chipproof 
and  new-looking  through  years  of  hard 
service.  Designed  with  rounded  edges  to 
prevent  the  lodging  of  crumbs  and  germs 
in  crevices,  Tenite  high -chair  trays  are 
completely  washable. 

Tenite  has  excellent  molding  properties 
which  often  lower  manufacturing  costs 


and  time.  Comparatively  large  sections 
such  as  these  trays,  may  be  cored  in  th 
mold,  thus  reducing  the  amount  of  Tenit 
used  but  not  lessening  the  strength  an< 
durability  of  the  completed  product 
Finisliing  operations  are  minimized,  sine 
the  high  permanent  luster  of  moldei 
Tenite  is  derived  from  the  polished  mold 

If  you  have  a  new  product,  investigat 
the  possibility  of  molding  or  extruding  i 
of  Tenite.  For  complete  information 
write  to  TENNESSEE  EASTMAN  CORPORA 
TION  (Subsidiary  of  Kastman  Koda! 
Company),  KIM;SPORT,  TENNESSEE. 


TENITE 


AN   EASTMAN  PLASTIC 


These  spiral  wound  tubes,  mad*  by  Precision  Paper    Tube   Co..   make   strong,   sturdy,   rigid  containers 

• 

Part  II.  The  manufacture  of  folded,  longitudinal-seamed  and  spiral-wound 
containers  tends  toward  mechanization  hut  much  development  is  needed 


mi 


CONTINUOUSLY  automatic  fabrication  from  start  to 
finish  is  nothing  new  in  paper  box  manufacture.  The 
units  HI"  operation  in  the  fabrication  sequence  are  essentially 
the  same  as  those  in  the  making  of  the  folded  container  of 
rigid  sheeting.  Yet  tin-  |>aper  box  process  is  not  adaptable  to 
plastics  containers.  The  chief  reason  is  that  plastics  re- 
quire hrat,  for  creasing  in  all  vases  and  for  cementing  in 
most  Paper  and  paper-board  can  be  scored  and  folded 
cold,  plastics  sheeting  would  crack  or  tear  under  the  same 
circumstances.  Nevertheless,  the  mass  production  of  folded 
containers  of  rigid  sheeting  calls  for  mechanization  and  con- 
tinuity of  r.perations  and  the  demand  will  inevitably  hasten 
that  development. 

The  manufacture  of  the  folded  plastics  container  is  still  a 
series  of  manual  operation-. — hand-fec<l  in  some  steps  of 
the  process  and  wholly  hand  operation  in  others,  each  at  a 


different  station.  First  the  .sheeting  is  ait  to  si/e.  Then  the 
corners  are  notched  out  in  what  is  essentially  a  blanking 
operation,  using  the  usual  knife-edge  blanking  die-. 

Creasing  may  be  applied  to  one  side  at  a  time,  or  to  two  or 
to  all  four  sides  in  a  special  set-up.  The  principle  of  the 
machine  remains  the  same,  in  any  case.  The  die  is  a  thin 
blade  of  tool  steel  tapered  to  a  blunt  edge.  It  derives  it- 
heat  from  the  top-plate  to  which  it  is  attached,  resistance 
heating  being  the  usual  method.  Depending  on  the  thick- 
ness of  the  material,  the  blade  i>  maintained  at  a  teni|>era 
ture  of  from  230°  to  250°  F  for  cellulose  acetate  and  from 
240°  to  260"  F  for  ethyl  cellulose.  Operation  consists  of  a 
lion  stroke.  The  heated  blade  is  first  brought  down  to 
make  contact  with  the  blank  and  is  held  there  for  a  second 
or  two  to  heat  the  material  at  the  line  of  the  fold.  Comple- 
tion of  the  stroke  sinks  the  line  of  the  fold  into  a  pad  of 
sponge  rublx-i  fastened  iii  the  bottom  plate  The  pouting  of 
the  compressed  rubber  against  the  sides  of  the  fold  brings 
tin  sideslip.  The  fold  sets  uitli  normal  cooling.  The  angle 
of  the  fold  is  determined  by  the  depth  to  which  the  mate]  ial 


26 


f»  I.  \  *  T  I  <  * 


JULY  194fi 


General  Chemical  Fluorine  Research  Presents  — 


THE  CATALYST  TO 

CHART  NEW  COURSES  FOR  AMERICAN  INDUSTRY 


Boron  Fluoride  Etherate  .  .  .  valuable  cata- 
lytic chemical  of  wide  ranging  potentiali- 
ties for  American  Industry! 

This  new  liquid  fluorine  compound  has 
a  multitude  of  uses.  Technical  literature- 
filling  volumes— contains  extensive  data  on 
(he  reactions  catalyzed  by  BFS  as  well  as 
by  its  complexes  with  other  organic  mole- 
cules. Repeated  reference  is  made  to  its 
superiority  to  other  catalysts  since  reac- 
tions are  moderated  znd  fewer  undesirable 
by-products  result. 

Outlined  at  right  are  some  of  the  prin- 


cipal applications  for  BF:1  as  a  catalyst.  Per- 
haps they  indicate  ways  in  which  you  can 
utilize  a  chemical  of  these  characteristics  in 
your  development  or  production  program. 
Boron  Fluoride  Etherate  is  commercially 
available  in  drums.  For  full  information, 
contact  General  Chemical  Company,  Flu- 
orine Division,  40  Rector  Street,  New  York 
6,  N.  Y.  When  writing,  if  you  outline  your 
proposed  application  for  this  new  catalyst, 
the  technical  experts  of  our  Fluorine  Divi- 
sion can  work  with  you  toward  an  early 
solution  of  your  problem. 


GENERAL    CHEMICAL    COMPANY 

40  RECTOR  STREET,  NEW  YORK  6,  N.  Y. 

Main  ana  Technical  He  nice  Office*:  Atlanta  .  Baltimore  .  Birmingham  (Ala.) 
Bottor  .  Bridgeport  (Conn.)  .  Buffalo  •  Charlotte  (N.  C.)  .  Chicago 
Cleveland  .  Denver  •  Detroit  •  Houiton  .  Kaniai  City  .  Los  Angelei 
Minneapolis  .  New  York  .  Philadelphia  .  Pittsburgh  •  Providence  <R.  I  ) 
Han  Francisco  •  Seattle  .  St.  LouU  .  Vtlc«  (N.  Y.)  .  Wenalchee 

Yaklma  (Wash.) 

In  WUcontin:  General  Oltemlnl  Wlsconaln  Corporation,  Milwaukee,  Wli. 

In  Canada:  The  Nichols  Chemical  Company.  Limited 

Montreal    .   Toronto    .    Vancouver 


Physical   Properties 

Formula: 


C2H5 


Mol.  Wl. 
Melting  PI. 
Boiling  Pt. 
Spec.  Or. 


O.BF, 


141 .» 

Less  than  — «0'C 

I25°C 

I.UatWC 

47.8%  min. 


Some  of  the  Principal  Reactions 
Catalyzed  by  BFj 

I.  Polymerization  of  unsaturated 
compounds  such  as  olefins,  diolefins, 
vinyl  ethers,  fatly  oils,  and  terpenes. 
The  products  may  be  solid  polymers 
useful  as  plastics  or  liquids  as  in  the 
bodying  of  drying  oils  for  paints  and 
varnishes. 

2.  Condensation  of  aromatic  nuclei 
with  olefins  and  diolefins,  paraffins, 
and  olefins,  and  aromatic  nuclei  or 
olefins  with  acids. 

*.  As  a  cyclizing  agent  for  rubber. 
T.  As  an  csterification  catalyst. 

5.  As  a  catalyst  in  the  synthesis  of 
aliphatic  acids  from  alcohols  and 
carbon  monoxide. 

v.  As  a  promoter  and  dehydrating 
agent  in  the  sulfonation  and  nitra- 
tion of  aromatic  compounds. 


JULY  1946 


PLASTICS 


27 


All  of  lhem«  »tep»  (left)  in  fabricating  a  folded  container  oi  Dow  "Ethocel"  are  performed  by  wholly  or  largely  manual  pro 
cedures  at  different  stations.  At  riqht.  a  heated  blade  sinks  the  sheeting  into  sponge  rubber  to  crease  a   folded  container 


is  depressed  into  the  rubber.  Stops  for  either  the  foot- 
pedal  or  the  top-plate  can  be  set  to  control  the  depth  of  the 
stroke  and,  therefore,  the  angle  of  the  fold. 

Semi-automatic  folding  machines — automatic  only  in  that 
the  hesitation  stroke  is  mechanically,  not  manually,  con- 
trolled— are  on  the  market.  But,  again,  feed  is  by  hand. 

Although  a  distinction  between  the  terms  "crease"  and 
"fold"  is  tending  toward  standardi/ation.  the  parlance  of 
the  trade  still  applies  them  more  or  less  indiscriminately. 
A  crease  is  regarded  as  being  at  an  angle  of  90°  or  less 
and  a  fold  as  being  at  an  angle  of  more  than  90°,  prevalently 
one  of  180° — in  other  words,  the  U-fold.  That  the  distinc- 
tion is  valid  is  apparent  from  the  fact  that  individual  ma- 
chines for  the  U-fold  and  the  90°-or-less  crease  are  coming 
into  the  industry. 

After  creasing,  the  piece  goes  to  the  cementing  operation. 
Cementing  is  done  under  mild  heat  and  pressure.  The 
creased  flanges  are  overlapped  on  a  guide-plate,  cement  is 
brush-applied  between  them  and  the  thumb  locks  the  joint 
as,  exerting  pressure,  it  travels  along  the  seam  to  complete 
the  bond.  With  an  improved  locking  device  now  in  use, 
pressure  is  applied  by  the  heated  upper  arm  of  the  unit  in- 
stead of  by  the  operator's  fingers. 

The  methods  just  described  are  for  the  corner-joined  con- 
tainer. The  operations  arc  essentially  the  same  for  the  side- 
joined  container,  but  the  sequence  differs  -omcwhat.  For 
the  side-seamed  t>ox,  there  are  two  blanks,  one  for  the 
folded  sides  ami  another  for  the  bottom.  The  side  strip  is 
notched  along  one  edge  to  provide  flanges  for  joining  to  the 
bottom.  The  flanges  are  creased,  the  open  edges  of  the  strip 
are  joined,  and  the  bottom  blank  is  cemented  to  the  flanges. 
This  is  a  more  labor-consuming  procedure  than  that  of  the 
corner-seamed  item.  Yet  it  is  the  only  method  for  a  folded 
c.iiitainer  with  a  beaded  top.  In  this  instance,  the  lx.-ad  is 
put  on  the  blank  after  notching.  Creasing  is  done  right 
through  the  bead.  The  two  ends  of  the  bead  are  telescoped 
in  a  side-wall,  and  the  seam  is  cemented  at  that  point.  Side- 
wall  seaming  is  also  utilized  in  the  making  of  the  top  and 
bottom  beaded  container,  in  which  the  lower  liead  scats  the 
container  bottom. 

It  would  appear  that  a  logical  method  of  mechanizing 
folded  container  fabrication  would  be  to  interpose  auto- 
matic feed  units  between  the  different  operations  to  provide 
continuity  of  process  and  to  make  each  unit  of  operation 
automatic  in  itself.  A  few  partially  automatic  machines.  .!<• 
signed  on  the  long  stroke  principle  by  container  manufac- 


turers for  their  own  use,  have  seen  some  production,  but 
there  is  still  a  distance  to  go  before  a  fully  and  continuously 
automatic  machine  becomes  available.  One  development 
that  may  be  of  considerable  assistance  in  the  problem  is  elec- 
tronic heating.  Electronic  heat  can  now  be  applied  in  a 
fine  line,  the  kind  of  line  which  would  constitute  scoring  in 
preparation  for  creasing. 

The  Longitudinal-Seamed  Container 

Although  fewer  individual  operations  are  involved,  the 
fabrication  of  the  longitudinally  seamed  cylindrical  con- 
tainer proceeds  on  the  lines  of  that  for  the  folded  container 
and  is  equally  hand-dominated.  The  blank,  cut  to  size,  is 
curled  around  a  mandrel  with  edges  lapping,  cement  is 
brush-applied  between  the  edges,  and  the  joint  is  locked  by 
finger  pressure.  An  improved  locking  procedure  is  one  in 
which  a  locking  arm  is  brought  down  on  the  joint  and  held 
there  to  set  it.  In  a  more  efficient  procedure  used  at  the 
See-Thru  plant  of  the  Clark  company,  a  cement-soaked  pad 
is  placed  beside  the  locking  unit  and  the  tubing  edges  are 
passed  across  the  pad  before  being  lapped  on  the  locker. 

One  or  two  fabricators  have  designed  for  their  own  use 
continuously  automatic  machines  for  making  the  tubing,  not 
including  end  closure.  Feed  is  off  a  roll  of  sheeting.  The 
material  advances  through  a  gradually  curling  guide  which 
rolls  the  strip  so  that  it  issues  from  the  guide  with  edges 
overlapping,  but  open.  Thus  curled,  the  cylindered  strip 
is  guided  forward  so  that  the  edges  ]i;i^  across  .1  cement 
applicator.  Issuing  from  this  point  and  still  guided,  the 
edges  are  locked  down  Ix-twcen  rollers  and  held  until  the 
joint  is  set.  A  synchroni/cd  ctit-otT  mechanism,  in  general 
similar  to  the  one  described  below  in  connection  with  the 
spiral-wound  container,  cuts  the  tulx-  to  length  "on  the 
run."  Capping  or  beading  and  seating  of  Ix.ttotns  is  car- 
ried out  in  a  separate  operation. 

In  connection  with  this,  as  also  w  ith  other  tv|>es  of  seamed 
containers,  one  possibility  that  has  apparently  not  been  ex- ' 
plored  is  the  welding  of  seams.  Kxcept  for  the  non-adhesive 
joint  (crimp-joined,  stitch-joined,  spun,  metal -hound,  etc., 
all  applied  mainly  in  the  attachment  of  metal  to  rigid  sheet- 
ing), seams  are  made  by  cementing  process,-*.  |M  all  cases, 
regardless  of  method,  the  resultant  scam  is  fully  visible. 

Both  manufacturers  of  rigid  sheeting  ami  fabricators  of 
containers  are  quite  aware  of  the  fact  that,  in  greater  or 
lesser  degree,  a  visible  si-am  is  a  sales  repellent.    A  welded 
seam  would  go  a  long  way  toward  diminishing  and  per- i 
haps,  in  some  forms,  eliminating  this  disadvantageous  visi- 1 


28 


PI.ASTMCS 


JULY   1946 


Two  ways  of  doing  a  job — one  entirely  by  hand,  the  other  machine-assisted.    At  left,  cement  and  pressure  form  the  corner 
joint  for  a  folded  container.    At  right,  the  machine  is  used  to  lock  a  cemented  seam  after  cement  has  been  applied  by  hand 


bility.  The  process  under  consideration  consists  of  using 
heat  to  reduce  the  edges  of  the  joint  to  viscous  liquefaction, 
closing  the  edges  to  a  butt  joint  and  permitting  resolidifica- 
tiiin  by  cooling  to  form  a  bond.  While  the  pressure  of  the 
soft  edges  against  each  other  in  effecting  the  joint  might 
throw  up  a  welt  along  the  line  of  the  joint,  it  would  seem 
possible  to  control  the  size  of  the  welt  at  the  time  pressure 
is  applied  and  to  reduce  it  altogether  immediately  afterward. 

The  Spiral-Wound  Container 

Diameter  for  diameter,  gauge  being  equal,  the  spiral- 
wound  cylindrical  container  is  considerably  more  rigid  than 
tin-  longitudinally  seamed  product.  This  is  apparent  from 
the  fact  that  the  seam,  which,  in  both  cases,  is  the  most  rigid 
portion  of  the  tubing,  is  greater  linearly  in  the  spiral-wound 
container  than  in  the  longitudinally  seamed  one.  The  lat- 
ter type  of  tubing  also  occasionally  has  the  tendency  to 
ovalize  because  of  the  unidirectional  stress  at  the  seam. 
Circularity  is  substantially  retrieved,  however,  by  groove- 
die  beading  of  top  and  bottom. 

An  idea  of  both  the  cross-sectional  flexural  strength  and 
the  end-to-end  compressive  strength  that  may  be  attained 
by  spirally  wound  tubing  can  be  gained  from  a  four-ounce 
tube  of  Ethocel  used  in  the  packaging  of  Dow-Corning  seal- 
ing compound  for  aircraft  engines.  Dow  Chemical  notes 
that  this  specimen,  4J4"  long  and  l-)-jj"  in  diameter,  will,  if 
placed  on  end,  support  a  man's  weight  and  that  a  truck 
could  run  over  the  package  without  seriously  damaging  it. 

Spiral  winding  is  not  confined  to  circular  cross-sections. 
Tubes  of  square,  hexagonal,  oval  and  other  cross-sectional 
contours  are  fabricated  in  the  same  way,  except  for  the 
cross-section  and  stracture  of  the  mandrel  and  the  provision 
for  advancing  the  tubing  along  it. 

Spiral-wound  tubing  for  containers  may  be  made  in  either 
single-ply  or  multiple-ply.  Single-ply  tubing  is  made  by 
lap-jointing  a  single  continuous  strip  of  sheeting.  In 
double-ply  tubing,  two  separate  strips  arrive  at  the  mandrel 
from  different  stations.  The  first  strip,  not  coated  by  ce- 
ment, is  wound  directly  on  the  mandrel  with  edges  butting. 
The  second  strip,  with  cement  applied  to  its  under  surface, 
is  wound  over  the  first.  It  is  fed  onto  the  first  in  such  a 
way  that,  with  its  own  edges  butting,  its  center  line  coincides 
with  the  butt  line  of  the  first  strip.  Although,  considering 
the  position  of  the  cement  along  the  face  of  the  material. 
•the  joint  actually  effected  is  in  the  nature  of  a  "straddle- 
lap"  joint,  the  effect  is  that  of  a  butt  joint  for  both  strips. 

Single-ply  tubing  is  a  more  economical  fabrication — for 


one  thing  because  feed  is  faster  for  the  single-ply  tube.  On 
the  other  hand,  the  double-ply  tube,  with  its  flush-edged 
seams,  has  a  smoother  finished  surface.  In  addition,  total 
sheeting  gauge  thickness  being  equal,  the  double-ply  tubing 
is  more  rigid. 

The  spiral-winding  of  sheeting  for  containers  is  generally 
done  by  a  machine  similar  to  one  developed  by  Celanese.  It 
is  continuously  automatic  for  the  series  of  operations  in- 
volved in  producing  the  tubing.  It  does  not  continue  through 
closure  of  the  ends,  which  is  a  separate  operation.  It  does, 
however,  continuously  execute  the  steps  of  feeding,  cement 
application,  winding  and  jointing. 

The  strip  of  sheeting  or  film  is  fed  off  a  roll  mounted  on  a 
shaft.  The  required  width  of  the  strip  for  the  diameter  of 
tubing  desired  is  determined  by  the  formula  W=  D  X  2.2 
(where  W  is  the  width  of  the  strip,  D  is  the  required  diam- 
eter of  the  finished  tubing  and  2.2  is  a  constant).  With  the 
elements  of  the  spiral-winding  set-up  correctly  positioned, 
this  formula  provides  an  approximately  45°  spiral  for  all  tube 
diameters.  This  strip  of  sheeting  is  drawn  from  the  roll  by 
the  traction  of  the  belt  around  the  mandrel  and,  in  order  to 
prevent  whipping  of  the  strip,  proper  tension  is  applied  by 
a  braking  element  on  the  roll  shaft. 

The  strip  receives  a  path  of  cement  along  one  edge  of  the 
under  surface  as  it  rolls  over  the  wheel  of  the  cementing 
unit,  which  picks  up  cement  solution  from  a  reservoir. 
The  ratio  of  the  width  of  the  cement  path  to  the  width  of  the 
strip  is  normally  about  1  :4,  with  a  maximum  of  J4"  of  ce- 
ment path  for  any  width  of  strip.  After  passing  under  a 
supporting  wheel,  the  strip  receives  a  single  twist  on  its  way 
to  the  support  roller.  Between  these  two  elements,  a  heat- 
ing plate  may  intervene  across  which  the  heavier  gauges  of 
material  would  be  made  to  pass  in  order  to  curl  freely  at 
the  mandrel.  With  cellulose  acetate,  for  gauges  from  .010" 
up,  the  temperature  of  the  plate  is  about  220°  F.  .For 
ethyl  cellulose,  the  Dow  Chemical  Company  recommends 
that  .010"  be  considered  the  maximum  gauge  lor  spiral 
winding,  in  which  case  no  heating  will  be  required. 

The  starting  end  of  the  sheeting  strip  is  given  two  or 
three  free  wraps  around  the  mandrel  before  being  received 
under  the  endless  belt.  The  belt  rides  around  the  mandrel  in 
continuous  motion,  and  the  strip  lap-winds  on  itself  between 
mandrel  and  belt.  The  tension  of  the  belt  on  the  seam  com- 
pletes the  bonding  of  the  joint,  and  the  angular  traction  of 
the  belt  pushes  the  completed  tubing  out  along  the  mandrel. 

The  mandrel,  of  cold-rolled  steel,  is  ground  smooth  and 


JULY  1946 


PLASTMCS 


29 


A  method  ol  making  a  lap  join!  on  a  longitudinally  seamed 
cylindrical  container.    This  depend*  largely  on  hand  work 

IN  highly  polished.     It*  length  iuu>t  In-  -iirticient   to  allow 
wrapping  of  the  belt  around  it.  as  well  as  to  provide  Mip 
port  for  the  tubing  after  it  issues  from  under  the  belt  and 
before  it  leaves  the  end  of  the  mandrel.    To  reduce  the  fric- 
tion generated  by  the  movement  of  the  strip  around  the 
mandrel,  mineral  oil  is  applied  by  a  saturated  pad  or  kiss 
roll  across  which  the  strip  passes  on  its  way  to  the  mandrel. 


CttttMT  OtTH 


Except  lor  the  fact  that  the  leed  roller  ii  not  shown, 
theee  three  drawings  give  complete  set-up  ior  continu- 
ous processing  ol  tubing  lor  the  spiral-wound  container 


The  Ix-lt.  l:tple»  and  usually  of  three-ply  cam  a-  ruhl'cr- 
faced  on  both  >ide>.  normally  has  a  width  in  the  ratio  of 
~:S  to  the  width  of  the  sheeting  strip.     It  is  mounted 
/untally  mi  two  pulleys  located  on  either  side  of  the  mandrel 
and  portioned  so  that  a  line  drawn  between  the  axes  of  the 
pulley*  is  at  an  angle  of  45    to  the  axis  of  the  mandrel.   The 
In-lt.  of  course,  will  follow  the  line  of  this  angle  of  approach 
to  the  mandrel.     The  upper  arm  of  the  In-lt  is  wrapped  once 
around  the  spiraled   strip  on   the  mandrel,  the  return  arm 
lieing  crossed  in  a  single  twist.    The  belt,  as  it  moves  around 
the  mandrel,  draws  the  wound   -trip  forward  and  around. 
applies  pressure  to  seal  the  joint  and  advances  the  finished 
tubing  along  the   mandrel.      Since   single-ply  cylimle- 
wound  at  a  much  more  rapid  rate  than  multiple-ply   (  most 
multiple-ply   tubing   is   produced   at    the    rate   of   about    sj\. 
linear  ft  per  min,  while  single-ply,  depending  upon  L. 
may  run  as  high  as   ID  times  that   rate),  variable  drive  is 
needed  for  the  pulleys  to  take  care  of   -uch  conditions  a> 
weight  of  stock,  number  of  plies,  diameter  of  lulling,  etc. 

For  spiral-wound  tubing  of  cro ectiotis  other  than  cir- 
cular, the  mandrel,  instead  of  K'ing  fixed,  is  mounted  on  a 
free-rolling  spindle.  Thus,  in  the  case  of  sc|uare-cros»- 
scctioned  tubing,  for  instance,  the  mandrel  revolves  freely 
with  the  movement  of  the  endless  U-lt.  It  is  obvious  that 
the  point  of  greatest  pressure  of  the  l>elt  on  the  tubing  would 
l>e  at  the  corners  and  that  a  In-lt  adjusted  to  provide  proper 
pressure  at  this  point  will  not  offer  adequate  pressure  to  the 
-ides  of  the  square.  The  prevailing  method  of  equali/ing 
pressure  at  all  points  is  to  use  lateral  ribbing  in  the  rubber 
facing  on  the  underside  of  the  I<elt. 

Continuity  of  automatic  fabrication  of  spiral-wound  con- 
tainers is  advanced  another  step  by  an  automatic  cut-off 
operation  for  cutting  the  tubing  to  length  as  it  issues  off 
the  mandrel.  The  cut-off  unit,  synchronized  with  the  ad- 
vance of  the  tubing,  is  set  up  near  the  mandrel  terminal. 
As  the  tubing  conies  off  the  mandrel,  it  rides  onto  a  support 
in  the  V-channel  on  which  it  advances  until  the  tubing  end 
arrives  at  a  tripper  stop  placed  at  a  distance  from  the  end 
of  the  mandrel  such  as  to  determine  the  length  of  the  piece 
of  cut  tubing  required.  When  the  tubing  end  displaces  the 
stop  element,  a  control  unit  is  triggered  into  action  which 
sends  a  saw  through  the  following  cycle:  saw  moves  at  right  ' 
angles  to  the  tubing  from  rest  to  cutting  position  ;  saw  moves 
parallel  to  tubing  in  synchronization  with  it;  saw  retracts 
and  returns  to  rest.  The  saw  is  in  continual  revolution  am 
makes  the  cut  at  the  begining  of  its  parallel  travel. 

There  are  sufficiently  sensitive  micro-switches  and  rel.,\s 
on  the  market  today  so  that  almost  hairline  displacement 
of  the  stop  element  will  actuate  the  controls  and  provide 
cuts  of  equal  length  within  reasonably  close  tolerances 
For  cuts  to  very  small  tubing  lengths,  it  is  often  found  that 
cutting  rate  can  not  keep  up  with  the  rate  of  production  ol 
tubing.  This  is  a  problem  that  still  awaits  a  solution  which 
will  not  introduce  a  hand-conveying  or  hand-Iced  step. 

With  the  cut-off  o|>eration  completed,  there  still  remains 
the  process  either  of  capping  the  tubing  (With  a  drawn  cap 
usually)  or  of  beading  it  and  seating  a  bottom.  If  either 
of  these  operations  could  be  automatically  tied  in  with  cut- 
off, the  whole  set-up  would  constitute  a  continuously  auto- 
matic sequence  of  container  fabrication  from  feed  to  finish. 
While  experimentation  is  going  on  in  this  direction,  the 
market  has  not  yet  seen  its  results.  In  designing  a  con- 
tinuoiisly  automatic  set-up,  the  alternatives  .nc  to  place  the 
cut-off  operation  either  ahead  of  or  following  the  closu 
operation.  It  is  likely  that  the  former  will  apply  for  .1  !>c.i 
seated  closure  and  the  latter  for  a  capping.  Incidentally,! 
for  complete  continuity  in  the  case  of  a  cap|H-d  contained 
the  cap  would  have  to  arnxc  .it  the  closure  point  from  an] 
automatic  drawing  station,  with  the  drawing  process  sy 
chronizcd  with  the  tubing  production.  I  TO  w  IOMIM  M 


M 


f*f..t«ri  ( 


.iri.V 


more  customers  Fr  turn  to 


plastic 


V 

trim 


You're  practically  certain  these  days  that  when  women 
open  their  purses  they're  "keeping  in  touch"  with  Styron! 
That's  because  more  and  more  purses  today  are  trimmed  with 
this  brilliant  Dow  plastic  material!  And  women  are  pleased 
by  the  suave,  modern  touch  of  Styron.  They  love  its 
lightness  and  smoothness,  its  clear  and  flawless  luster. 
They're  finding  out,  too,  that  Styron  stars  in  performance, 
that  it  won't  lose  its  shape  or  crack  or  discolor.  Women 
are  learning  that,  along  with  luxurious  beauty,  Styron 
gives  values  they're  seeking.  That's  why  women  are  turning 
to  Styron — in  purse  trim,  in  numerous  fine  products.  It's 
because,  as  so  many  manufacturers  know,  Styron  is  the 
name  you  can  depend  on  in  plastics! 


Success  in  plastics  is  best  measured  in  end  products.  It  calls  fo- 
combined  efforts  of  manufacturers,  designers,  fabricators,  run 
material  prtxlucers.  Dow  /.v  reaitv  to  tin  its  part.  Sfice  time  nn*< 
money — call  on  Dow  and  gc<  the  moit  out  o£ pjaitici. 

PRESENT  AND  POTENTIAL  USES— Lighting  fixture?,  anil  displays;  insulators;  hydrometer^: 
battery  ca»es;  funnels;  bottle*;  closures;   tond  handling  equipment;  pharmaceutical. 
ind  jewelry  containers;  jewelry;  advertising  items;  refrigerator  parts;  pen-. 
•!-;  chemical  apparatus;  lenses;  decorative  objects  and  trim. 

PROPERTIES  AND  ADVANTAGES -Beautiful,  clear,  transparent;  "pipes"  light  through  r«<< 
around  corners,  etc.;  resistant  to  acids  and  many  alkalies;  stable  at  low  temperatures; 
excellent  electrical  properties:  broad  color  range;  low  specific  gravity,  providing  more 
moldings  per  pound;  low  water  absorption. 

fMt  DOW  CHtMICAl    COMPANY     MIDLAND    MICHIOAN   .  N«w  Tack.  lotion,  Philadelphia.  Wjihinjl.n.  Cl.y»l«nd    D^toil    Chicago.  St.  loull.  H«l»«lori.  tan  Fraixltc*.  IK  Alt**)**.  SMH 


PLASTICS 

ETHOCEL         •        ETHOCEL  SHEETING 
STYRON      •     SARAN      •     SARAN  FILM 


New  Du  Pont  material   finds  numerous  applications   in  industrial 
articles   such   as   spacers,   gaskets,   tape,   cylinders,   tubing,    pipe 


makes  its  debut 


f 


New  resin  displays  excellent  insulating 
qualities,   good  resistance   to  heat  and  chemicals 


A\tH  industrial  plastics  which  retains  its  strength  and 
form  at  higher  temi>f  ratures  than  any  known  organic 
material,  and  has  remarkable  chemical  resistance,  was  re- 
cently announced  by  E.  I.  du  Pont  de  Nemours  &  Co.,  Inc., 
before  the  American  Chemical  Society.  This  new  material, 
tetrafluoroethylcne  resin,  is  to  be  designated  by  the  trade 
name  of  Teflon,  and  was  one  of  the  new  developments  tea 
tur.-'l  by  Du  Pont  at  the  SPI  National  Plastic-  Imposition 

Pilot  plant  production  of  commercial  quantities  of  this 
resin,  which  was  developed  in  Du  Pont's  research  labora- 
tories, was  started  in  1943  for  war  purposes  by  the  plastics 
deportment  of  the  company. 

Teflon  is  said  to  withstand  temperatures  as  high  as  575° 
1.  conversely,  to  exhibit  no  adverse  affect-  when  sub- 
jected to  a  temperature  of  — 75°  F.    As  tor  it-  chemical  re- 
sistance,  it  withstands  the  attack  of  all  materials  except 
molten  alkali  metals,  being  unaffected  by  such  reagent-  .1- 
chlorosullonic  acid,  acetyl  chloride,  boiling  solutions  of  -., 
dium  hydroxide,  and  even  aqua  rcgia.  With  these  prop 
its  makers  predict  a  wide  range  of  industrial  application-  for 
Teflon,  which  is  also  reported  to  be  resistant  to  attack  of 


'Teflon"   products  are  also  tough,   have  high  impact   strength 


32 


PI.AKTICK 


JULY   194« 


WATERTOWN  PLASTICS 

TAKE  TO  THE  AIR 


•  THK  FKEE-KLictiT  CHASSIS  in  this  powered  model  plane  is  molded  by  Watertown  of  cellulose 
acetate  butyrate— a  thermoplastic  material  noted  for  its  dimensional  stability— resistance  to  impact 
—uniformity— and  ability  to  withstand  all  weather  conditions.  This  one-piece  plastic  chassis  contains 
a  built-in  coil,  flight  timer,  condenser  and  batteries  and  fits  into  the  fuselage  of  the  model  plane. 
The  wheel  struts  and  engine  are  connected  to  the  plastic  rasing— proof  of  its  strength  and  ability  to 
stand  impact,  jar  and  vibration. 

The  Bard-Parker  Company  chose  Watertown  to  mold  this  free-flight  chassis  because  of  Watertown's 
long  experience  and  proven  ability  in  molding  to  rigid  manufacturer's  specifications.  Watertown's 
engineers  offer  you  this  same  experience  and  ability  for  all  of  your  plastic  products,  whether  they 
require  thermosetting  or  thermoplastic  materials.  Write  to  THE  WATERTOWN  MANUFACTURING  COM- 
PANY, Watertown,  Connecticut.  BRANCH  OFFICE— Cleveland.  SALES  OFFICES— New  York.  Chicago, 
Detroit.  Milwaukee  and  Hawaii. 


NAME     AS     OLD     AS      THE     PLASTICS     INDUSTRY 


JULY  1946 


organic  materials  and  strong  alkali-  It*  iK-ace-time  contri- 
butions have  already  begun  in  such  modern  engineering 
developments  as  the  jet  engine,  where  it  is  used  as  gaskets 
and  wire  insulation,  and  its  use  in  aircraft  ignition  systems, 
near  spark  plugs,  is  cited  as  another  proof  of  its  heat-r<-~i--t- 
ance. 

Important  use  in  the  radio,  radar,  and  television  fields  is 
also  reported  for  this  new  plastics,  in  conduits  subject  to 
attack  by  corrosive  materials,  and  in  spacers  for  coaxial 
cables  conducting  extremely  high  frequency  circuits.  Its 
dielectric  loss  factor  is  extremely  low,  even  at  frequencies  up 
to  3000  megacycles ;  its  resistance  to  surface  arc -over  is  ex- 
cellent, and  on  failing,  it  melts  and  vaporizes  rather  than 
carbonizing  to  leave  a  conducting  path. 

Numerous  Uses  Anticipated 

Among  the  industrial  applications  forecast  for  Teflon  are 
many  in  instances  where  unusual  resistance  to  solvents  and 
corrosive  agents  is  demanded,  and  where  insulation  against 
high-frequency  current  is  called  for,  in  combination  with 
one  or  both  of  those  properties.  Included  in  the  uses  men- 
tioned are  hydrochloric  acid  systems,  pump  gaskets,  hiKli- 
tempcrature  heating  systems,  tubing  and  piping  for  chemical 
plants,  distillation  equipment  for  acids,  and  all  types  of  in- 
sulation. 

High  impact  strength,  toughness,  and  water-absorption 
so  low  as  to  be  rated  "zero"  are  also  claimed  for  this  new 
resin. 

The  resin  is  made  by  polymerizing  gaseous  tetrarluoro- 
ethylene  to  yield  a  solid,  granular  polymer.  The  fluorine 
atoms  in  the  molecule  impart  exceptional  properties  of  re- 
sistance to  heat  and  to  chemicals.  While  Teflon  has  no  true 
melting  point,  it  undergoes  a  solid-phase  transition  at  620° 
F,  with  a  sharp  drop  in  strength ;  and  at  a  temperature  of 
about  750°  F,  it  decomposes  slowly  to  yield  the  gaseous 
monomer  plus  a  few  other  gaseous  fluorine  derivatives. 
Small  amount^  of  thiorine-containing  gases  are  emitted  at 


temperatures  above  420°  F,  and  since  the  toxicology  of  these 
resins  is  not  fully  understood,  the  company  advises  good 
ventilation  as  a  requisite  for  extrusion  and  other  mechani- 
cal operations  in  which  these  temperatures  may  be  attained. 

Rods  and  tubes  of  Teflon  are  extruded  in  continuous 
lengths  by  screw  stuffers  of  the  conventional  type,  although 
special  techniques  are  required ;  electric  heating  pads  regu- 
lated by  controllers  must  be  used  in  order  to  obtain  the  high 
temperatures  required  for  extruding.  Although  the  extru- 
sion rates  vary  all  of  them  are  measured  in  terms  of  fph, 
which  is  slow  in  comparison  to  those  of  other  thermoplas- 
tics. The  rate  is  also  slow,  compared  to  conventional  opera- 
tions, in  wire-coating,  which  is  handled  by  using  a  cross- 
head  die  on  a  screw  stuffer,  with  careful  control  of  rates 
and  of  temperatures.  It  is  possible  that  dip-coating  methods 
may  be  feasible,  although  further  development  work  will  be 
required. 

Stating  that  Teflon  can  be  machined  very  easily  with 
standard  wood-working  or  metal-working  tools  as  long  as 
they  are  kept  sharp,  the  company  advises  that  until  molding 
techniques  are  more  fully  developed,  it  is  necessary  to  form 
articles  of  complicated  shape  by  machining  some  of  the 
available  standard  shapes  of  the  material.  A  punch  press 
can  be  used  to  work  sheet  stock;  thin-walled  tubing  can  be 
flared  with  the  standard  flaring  tools  used  for  copper  tub- 
ing ;  and  heavy  tubing  can  be  threaded  by  means  of  standard 
pipe-threaders. 

The  material  in  thin  sections  is  transparent,  with  thicker 
pieces  being  waxy  in  appearance,  and  white  or  gray  in 
color.  No  colored  forms  of  the  resin  have  been  developed, 
but  success  has  been  met  in  the  addition  of  various  inor- 
ganic fillers.  Inasmuch  as  nothing  adheres  to  its  surface 
with  any  mechanical  strength,  no  cement  has  been  found  for 
Teflon;  the  aforementioned  property  has  been  suggested  as 
an  advantage  in  cases  where  a  non-sticky  surface  is  essen- 
tial, such  as  containers  to  hold  preforms  in  electronic 

(Continued  on  pagf  ''"  I 


Dielectric  constant  and  power   factor  oi  "Teflon"  measure  a«    3000   raeq.    Right,   rod*  ol   "T«Qon"  and   two  other   plastic* 
are  Immersed  In  nilhirie  acid  bath.    R..ult.  (how  •T.Bon"  rod    completely    unaffected:    oth.n    deteriorated    and    swollen 


PLASTICS 


JULY 


A  few  of  the  thousands  of 


products  that  can  be  made  from  GEON 
raw  materials 

Boldly  but  beautifully  colored  shower  and  window  curtains... 

a  delicately  shaded  shower  cap  . . .  baby's  modern  spotproof  bib  and 

mother's  gay  apron  . . .  sister's  stylish  raincape . . . 

All  these  were  fabricated  from  flexible  films  made  from  GEON  raw 
materials.  But  they're  only  a  handful  of  the  thousands  of 
exciting  new  products  that  can  be  made  from  GEON.  For  versatile 
GEON  may  be  pressure  or  injection  molded,  extruded, 
calendered,  cast  into  sheets  or  film,  or  applied  as  coatings  to  all 
types  of  textiles  and  papers. 

And  products  made  from  GEON  may  have  any  number  of  unusual 
properties  in  a  wide  variety  of  combinations.  For  example,  products 
made  from  GEON  may  be  made  resistant  to  water,  oils,  acids,  foods, 
air,  heat,  cold,  abrasion,  mildew,  cracking,  creasing,  and  many  other  normally' 
destructive  factors.  They  may  be  brilliantly  or  delicately  colored; 
flexible  or  rigid;  transparent  or  opaque.  There  are  applications 
for  GEON  in  literally  every  home,  every  industry. 

For  more  information  about  GEON  please  write 
Department  U-7,  B.  F.  Goodrich  Chemical  Company,  Rose 
Building,  Cleveland  15,  Ohio. 


Geon 


B.  F.  Goodrich  Chemical  Company 


A  DIVISION  OF 
THE  B.  f.  GOODRICH  COMPANY 


In  your  starch  for  a  good  molder 
You  need  not  travel  far 

for  (lie  right  spot  to  land  .  .  . 
Just  drop  in  on  us  at  Boonton. 


Here  you  will  find  surprising  things 
in  the  way  we  make  plastic  parts  .  .  . 
electronics  all  over  the  place 

and  processing  machines  really  uncanny. 


Of  course,  if  you  can't  visit  us  conveniently 
to  see  our  real  up-to-date  shop  .  .  . 

We've  Mohammeds  who  come  to  the  mountains 
NVho'II  confer  ahout  your  problems  ...  on  your  lull 


You'll  find  a  well-knit  organization 

that  knows  the  meaning  of  esprit  de  corps  .  .  . 

Men  known  for  their  ingenuity,  skill,  experience  .  .  . 
\\lio  turn  out  work  that's  second  to  none. 


Phone  the  Mohammeds 

In  the  New  York  Office  .  .  . 
Tell  them  your  problems  .  .  . 
Arrange  with  them  for  a  vi-it. 


Our  "Ready  Reference  for  Plastics"  Is  yours  if  it  will  help  you  ouy  or  design  plastic  moldings. 


1 


Shelves  are  automatically  dipped  into  resin  bath  ior  the  application  of  the  first  of  two  plastics  coatings 

Coating  Refrigerator  Shelves 

Application  of  a  special  plastics  finish  makes  the  shelves  of 
the  modern  refrigerator  durable,  sanitary,  corrosion-resistant 


M 


man 


AS  Servel,  Inc.,  Evansville,  Indiana,  swings  back  from 
war  production  to  big-scale  output  of  gas  refrig- 
erators, it  is  featuring  the  application  of  a  synthetic  resin 
coating  for  refrigerator  shelves  as  a  distinct  quality  advance 
over  pre-war  shelves. 

This  coating  is  applied  by  dipping  the  shelves  in  an  alkyd- 
urea  formaldehyde  type  resin,  which  is  then  set  by  baking. 
In  weatherability  (humidity,  temperature,  resistance  to  sun- 
light), abrasion  and  corrosion  resistance,  flexibility,  and 
gloss  and  color  retention,  the  coating  is  considered  an  en- 
gineering advance  in  the  achievement  of  a  uniform  coating 
on  fabricated  wire  products.  Besides  these  merits,  it  is  also 
reported  non-brittle,  uniform  in  color,  and  free  from  tears 
along  the  drainage  edge,  coating  sags,  and  runs. 

The  process  of  applying  the  coating  involves  a  four-step 
procedure:  (1)  zinc  plating,  (2)  bonderite,  (3)  two-coat 
dip,  and  (4)  electrostatic  de-tearing.  Equipment  includes 
electroplating  equipment;  a  conveyor  system;  gas  relief  and 


curing  ovens;  cooling  tunnels;  dip  tanks,  pumps,  filters, 
paint  mixing  equipment,  and  piping ;  electrostatic  de-tearing 
equipment ;  and  a  ventilating  system  for  the  dip  room. 

In  beginning  the  four-stage  operation,  two  operators  un- 
crate  the  bare  steel  food  shelves  of  spotwekled  construction 
and  load  them  on  plating  racks,  hanging  on  castered  dollies, 
which  are  then  moved  to  fully  automatic  zinc  plating  and 
bonderite  machine.  Four  to  125  shelves  are  hung  on  each 
plating  rack,  depending  upon  the  type  of  shelf  hung.  Solu- 
tions in  the  plating  machine  are  balanced  for  a  speed  of  84 
plating  racks  per  hour. 

Beginning  the  sequence  of  operations  and  baths  performed 
by  this  machine,  plating  racks  are  removed  from  dollies  and 
placed  on  the  plating  machine.  Then  the  ware  is  (1)  elec- 
tro-cleaned for  six  minutes  in  an  alkali  solution  to  remove 
grease  and  dirt;  (2)  rinsed  in  a  tank  of  clear  water;  (3) 
bathed  in  a  muriatic  acid  pickle  tank  for  seven  minutes  to 
remove  scale  and  prepare  surface  for  zinc  plating;  (4) 
rinsed  in  two  clear  water  rinse  tanks;  (5)  travels  through  a 
7800  gallon  zinc  cyanide  plating  tank  for  13  min.  to  receive 
a  coating  of  zinc  from  .0004  to  .0008"  thick;  (6)  rinsed  in 
two  clear  water  rinse  tanks;  (7)  dipped  into  an  oxalic  acid 


J 


ULY  1946 


PLASTtCS 


37 


Dilution  for  one  minute:  <8i  riiix-d  in  a  clear  water  rin>e 
tank;  I  «J  I  dipped  in  a  bonder  ite  tank  for  one  minute  to 
receive  :i  phosphate  coating;  (10)  dipped  in  a  cold  water 
rinse  tank  ;  (111  dipped  in  a  hot  water  rinse  tank  ;  and  (  12) 
dipped  in  a  chromic  acid  rinse  tank,  i  Chemical  analyses 
are  made  daily  on  electro-clean,  muriatic  acid,  zinc,  oxalic 
acid.  lionderite.  and  chromic  acid  solutions.  Additions  are 
made  to  these  solutions  to  control  liaths  within  their  limits  \ 

The  operator  next  removes  the  plating  racks,  places  them 
on  catered  .lollies,  and  moves  the  ware  to  the  automatic 
plastics  coating  machine  located  a  short  distance  from  the 
plating  machine.  <  >nly  OIK-  operator  i>  required  lor  these 
operations. 

Two  operators  transfer  food  shelves  from  plating  racks 
directly  to  the  plastics  editing  conveyor.  Shelves  are  hung 
on  individual  hooks  attached  to  master  hangers.  Twi.  COT- 
rugated  nails  are  s|mt\\elded  to  the  individual  hooks  and 
support  the  food  shelves,  thus  insuring  the  least  possible 
contacts  with  the  hooks.  Master  hangers  ;ire  spaced  M" 
apart  on  the  conveyor  and  run  at  the  rate  of  (<7  \*r  hour. 
Km  to  Id.'  shelves,  depending  on  the  type  of  shelf,  are 
hung  on  each  masteV  hanger.  There  are  34  variet  • 
shelving  involved. 

The  ware  enters  a  hydrogen  relief  oven,  at  350°  F,  where 
it  remains  for  10  mill.,  to  relieve  gases  from  the  plating. 
It  then  makes  ;,  15  min.  trip  through  the  first  cooling  tunnel, 
from  which  it  is  carried  into  the  dip  room,  where  it  is  au- 
tomatically dipped  into  the  prune  tank. 

Next,  the  ware  passes  over  a  metal  drain  pan  and  enters 
the  de-tear  area,  then  goes  over  two  electrostatic  de-tear 
grids  which  remove  the  tears  of  surplus  plastics  from  the 
iNittom  of  the  shrives.  The  shelves  and  grids  are  kept  eight 
inches  apart.  The  grids  are  equipped  with  remote  hydraulic 
controls  by  which  they  can  In-  raised  or  lowered  on  different 
length  ware  to  maintain  proper  distance. 

I  he  conveyor  then  carries  the  ware  into  the  first-coat 
nn  fai/c  75  I 


A  periodical  check  U  being  made  of  the  plastics  finish 
on  a  run  of  samples  being  tested  in  the  weathetoraeter 


A*  an  early  step  in  the  coating  process,  racks  loaded 
with  food  shelves  are  transferred  from  dollies  to  the 
carrier  of  the  automatic  plating  machine.  Below,  the 
shelves  are  lowered  into  Bonderite  tanks  to  receive  a 
coating  of  phosphate  at  another  pre-plastics  operation 


.11  l.Y    I'UH 


the  famous 


and  ^4LL  Jfeese  advantages: 


Get  a 


THERMEX  Red  Heads  are  a  product  of  The  Girdler  Corix>ration, 

Thrrmex    Division,    Dept.    PM-7,    Louisville    1,    Kentucky.      District 

offices:  150  Broadway,  New  York  7,  N.  Y.;  228  N.  I^aSalle  Street, 

Chicago  1,  Illinois;  183K  Euclid  Avenue,  Cleveland  15,  Ohio 


Widest  range  of  fully  developed  models  from  which 
to  fit  your  needs 

Developed  especially  for  the  plastics  industry 

Compactly  designed  to  fit  present  press  layouts 

Dual  timer  control 

Every  model  portable 

Easy  to  install 

Completely  self-contained 

Dependable 

Simple  to  use 

With  the  exclusive  sliding  drawer  heating  compartment 

Automatic  signal  light  _, 

Automatic  resetting  timer 

Convenient  working  height 

Accessible  control  panels 

Large  load  area  that  takes  small  and  large  preforms 

Warp-proof  load  drawer 

Adequate  metering 

Overload  and  underload  protection 

Automatic  safety  switches  on  sliding  drawer  and 
maintenance  doors 

Air-gap  with  all  loads 

Maximum  uniformity  of  heat 

Moisture  condensation  eliminated 

Efficient  air  cooling  system 

Rugged  construction 

Heavy-duty  copper  plated  cabinet 

Maximum  protection  against  radiation  leakage 

Economical  power  consumption 

Service  by  fully  qualified,  factory-trained  specialists 


THKRMKX  and  RKP  I  h  AM 
Trade  Marks  Rj'g. U.S.Pat. Off. 


JULY  1946 


PLASTMCS 


39 


WEAVING 


plastics   Field   Editor 


IN  ANNOUNCING  that  it  is  undertaking  to  "translate" 
the   fabrics   custom-designed  by   Dorothy   Liebes   into 
power-loomed  plastics-coated  fabrics,  the  Reading  Division 
of  Goodall  Fabrics  has  provided  an  opportune  occasion  for 
an  analysis  of  this  designer's  work. 

Mrs.  Liebes,  who  has  had  a  distinguished  career  in  textile 
design,  has  for  some  time  been  incorporating  plastics  mate- 
rials into  the  multifibered  fabrics  she  has  designed  and  hand- 
loomed  in  her  San  Francisco  studio  and  workshop,  for 
upholstery,  draperies,  Venetian  blinds,  place  mats,  lamp- 
shades, handbags  for  evening  use,  and  other  applications 
where  a  unique  custom-made  product  is  desired. 

There  is  still  a  necessity  for  stressing  tin-  principle  that 
the  best  design  is  that  which  is  based  on  the  nature  of  the 
material  used.  Since  new  designers  keep  coming  into  the 
field  with  only  a  hazy  initial  knowledge  of  pla>tic-.  they 
mu-t  IK-  reminded  that  they  are  not  working  in  glass,  wood, 
rubber  or  brass,  but  in  a  special  variety  of  synthetic  chemical 
compounds  with  properties  which  must  be  carefully  studied 
before  attempting  to  use  them  for  any  product — consumer 
or  industrial. 

This  does  not  mean  that  all  designs  are  so  dra-tically 
determined  by  the  material  that  the  individuality  of  the 
designer  is  submerged.  On  the  contrary,  the  measure  of  a 
designer's  talent  is  the  degree  to  which  he  can  IK-  "different" 
when  he  is  working  under  the  same  limitation.-  a-  other 
designers. 

In  the  case  of  Mrs.  Liebes,  the  use  of  plastics  has  not 
changed  her  basic  talent  and  taste,  and  it  is  the-e  diarac- 
teri-tics  which  have  been  drawn  on  in  the  new  material. 
Mrs.  Liebes  has  long  had  a  decided  penchant  for  mixed 
yarns,  used  in  some  cases  in  combination  with  various  reeds. 
Jute,  sisal,  cotton,  ramie,  hemp,  bamboo  are  a  few  of  the 
natural  materials  which  she  has  commonly  employed.  Yet, 
she  has  also  taken  synthetic  fibers  in  her  stride,  one  of  her 
most  striking  achievements  being  a  combination  of 
chartreuse-green  rayon  interwoven  with  clear  extruded  vinyl 
filaments.  This  is  the  key  to  her  basic  approach  in  adapting 
l>la-tics  to  her  fabrics — to  blend  them;  to  consider  plastics 
as  simply  another  thread  to  enrich  the  warp  or  woof  of 
textiles. 

Mrs.  Liebes  has  produced  a  vast  assortment  of  designs, 
with  a  wide  variety  of  textures  and  color  harmonies — some 
in  monotone  or  softly  blended  shades  of  the  same  color, 
others  in  vivid  tones  with  bold  contrasts.  She  has  used 
plastics  in  the  same  flexible  manner.  First  of  all,  she  has 
taken  advantage  of  the  various  forms  in  which  plastics  lend 
themselves  to  textiles.  Thus  she  ha-  leaned  lu-a\ily  on 
extrusions — filament-  and  -trips,  but  has  also  used  beads 
and  coatings  (on  metal  thread  i  \gain.  though  she  ha- 
largely  favored  the  vinyls,  she  has  also  found  a  place  for 
acetates  and  even  Catalin  cast  resin,  and  there  will  no  doubt 
be  others. 

A  few  patterns  from  her  great  collection,  shown  in  the 
accompanying  illustrations,  give  -ome  indication  of  the 
variety  of  combinations  which  she  employs  Me-ide-  the 
rayon-vinyl  upholstery  material  previously  leiem-d  to,  there 
is  a  Venetian-blind  fabric  in  which  extruded  vinyl  filament- 
and  strip-,  together  with  natural  reeds,  are  prominent  in  the 


40 


PLASTICS 


JULY  194« 


VERSATILITY  into  FABRICS 

Designer  Dorothy  Liebes  incorporates  plastics  materials  in  her 
textiles  to  emphasize  an  essential  quality  of  the  basic  material 


warp,  while  traditional  threads  in  a  spectrum-band  richness 
make  up  the  weft.  Both  plastics  are  yellow,  but  have  differ- 
ent texture,  the  filaments  having  lower  reflection  quality 
than  the  strips.  This  effect  of  contrasting  textures  was  also 
achieved  in  fabric  woven  in  gradations  of  yellow,  but  matte- 
surfaced  despite  the  naturally  bright  color.  Here  again  a 
strip  of  vinyl  was  used  to  provide  a  refreshing  contrast. 

Behind  the  manipulation  of  plastics  elements  by  this 
designer  is  her  dislike  of  what  she  calls  the  "laboratory 
look"  of  so  many  plastics  films  and  fabrics.  This  is  not  a 


naive  "anti-science"  bias,  but  a  purely  aesthetic  reaction  to 
what  Mrs.  Liebes  conceives  as  poverty  of  texture  and  color 
range  in  these  materials.  Another  thing  to  which  Mrs. 
Liebes  has  definite  objections  is  the  attempt  to  make  plastics 
materials  simulate  traditional  materials,  in  surface  or  in 
weave.  The  most  successful  application  of  plastics  in  tex- 
tiles, she  feels,  is  one  which  brings  out  some  essential  quality 
of  the  basic  material — for  that  constitutes  its  uniqueness  and 
emphasizes  the  qualities  which  make  it  particularly  desirable 
for  the  application.  END 


Porch  furniture  fabric  has  a  soft  green  vinyl  filament 
running  through  it.  Broad  strips  are  also  of  vinyl, 
in  a  bright  blue  to  contrast  with  the  dominant  greens 


Vivid  contrast  between  the  clear  vinyl  filaments,  the 
reeds  and  pile  fabrics — all  combined  in  a  textile  designed 
for  Venetian  blinds  and  lampshades — is  clearly  seen 


Eye-catching  color  band  of  the  spectrum  is  duplicated 
in  alternating  vertical  weaves  of  greens,  greys,  yel- 
lows, reds.  Filaments,  some  strips,  are  of  yellow  vinyl 


A  striking  upholstery  covering,  having  a  luminous  and 
light  weight  appearance,  is  obtained  when  chartreuse 
rayon  is  combined  with  an  extruded  clear  vinyl  strip 


JULY  1946 


PLASTICS 


41 


Also 

manufacturers 
of  Extrusion 
Moldings  — 


—and  plenty  of  what  it  tak*. .« 
/;/  ingenuity! 


YOU  specify  the  size,  the  shape  and  the  dimensions — or  leave  it  all  to 
us.  We  render  BOTH  types  of  Molding  service,  in  endless  variety — up 
to  22  ounces  per  shot;  accurately  made — beautiful  to  behold! 

AN    EXPERT  TECHNICAL   STAFF   ALWAYS   AVAILABLE 


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v.  — 

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>  ~,    >,  a 


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C     g     B.    D>  JJ 


Ifc 


fl 


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JCnow  Your 


Tested  by  use,  these  thermosetling 
resins  rate  high  in  form  retention, 
heat  and  water  resistance,  surface 
hardness,  and  electrical  properties 


'Plcukon    ••lonilD*  and  alpha  c»llulo««  filled  "M»lrnac"  or* 
both  u«*d  lor  hearing  aid  houmlnqt    ThU  U  th«  "Sonolon* 

44 


A -THOUGH  the  application  of  melamine  resins  to  the 
field  of  molding  plastics  was  greatly  accelerated  by 
the  war,  these  versatile  thermosetting  compounds  seem  des- 
tined to  find  a  permanent  place  in  the  family  of  peace-time 
plastics. 

The  Armed  Services  in  their  never-ending  quest  for  new 
the  better  products  were  quick  to  perceive  the  potential 
merit  <>f  the  newly-developed  melamine  plastics,  with  the 
result  that  development  work  was  speeded  rather  than  re- 
tarded by  the  outbreak  of  war.  As  a  consequence,  they 
entered  the  civilian  plastics  picture  as  a  proved  mate- 
rial, having  been  tried  and  tested  under  exacting  combat 
conditions. 

Melamine  molding  compounds  are  made  with  a  variety 
of  fillers,  each  of  which  imparts  certain  qualities.  Thus, 
melamine  filled  with  alpha  cellulose  is  characterized  by  its 
wide  color  range;  resistance  to  water  and  organic  solvents: 
excellent  electrical  properties;  improved  resistance  to  heat, 
weak  acids  and  alkalies ;  pronounced  surface  hardness :  and 
improved  dimensional  stability.  These  properties  suggest  a 
host  of  peace-time  application-*. 

Dress  buttons  for  service  uniforms,  for  instance,  have 
proved  highly  successful.  Used  on  both  washable  uniforms 
and  those  requiring  dry  cleaning,  melamine  buttons  have 
UTII  outstanding  in  their  freedom  from  checking  and  their 
retention  of  original  gloss,  color,  and  general  appearance 
even  after  repeated  laundering  or  dry  cleaning.  These 
properties  indicate  a  bright  future  in  the  high-grade  button 
field. 

Molded  tableware  has  likewise  made  use  of  the  same 
properties  of  water  resistance,  chemical  inertness,  and  hard- 
ness. These  qualities,  coupled  with  light  weight  and  satis 
factory  strength,  have  made  possible  tableware  which  ha- 
seen  wide  service  in  the  Navy,  in  hospitals  and  elsewheie. 
and  are  now  being  promoted  for  consumer  use,  especially 
for  picnic  and  other  uses  where  formal  chinaware  service 
i-  not  necessary.  The  introduction  of  pastel  colors  in  this 
product  has  greatly  enhanced  its  appeal. 

The  melamine  compounds  have  also  found  application  in 
electrical  connectors  and  similar  parts  where  their  excellent 
arc  resistance,  dielectric  strength,  and  insulation  resistance 
over  a  broad  range  of  temperature  and  humidity  conditions 
have  tilled  distinct  needs  in  the  Armed  Services.  It  is  an- 
ticipated that  the  peace-time  electrical  industry  will  likewise 
find  these  properties  of  interest  in  the  design  of  new  prod- 
net-,  and  the  re-styling  of  old  ones. 

Another  interesting  application  of  melamine  is  its  use  in 
a  small,  molded  hearing-aid  earphone,  which  houses  a  deli- 
cate mechanism.  It  is  successful  in  this  use  where  any 
pronounced  change  in  dimensions  would  seriously  affect  the 
functioning  of  the  earphone. 

Among  the  other  possible  fields  of  application  suggested 
l>y  the  properties  of  this  adaptable  material  are  cosmetic 
jars  for  water  base  creams,  fruit  juicers  (because  of  its 
.11  id  resistance),  vacuum  bottle  caps,  refrigerator  parts. 
stove  hardware,  and  numerous  other  decorative  and  utili- 
tarian item-. 

Cellulose-filled  melamine  lends  itself  readily  to  comrn- 
tional  compression  molding  methods  as  well  as  to  transfer 
molding  procedures  It  is  easily  preformed  in  standard 


JULY   1916 


MOLDED  BY  MACDONALD  MFG.  CO.  FOR  CINDERELLA  MFG.  CO.,  NEW  YORK  CITY 


THE  IflfORLD  OF  TO  ITS  •••  Jhisgay  looking  gent  is  "Happo"  -a 
pioneer  for  plastics  in  the  mechanical  toy  field.  Pull  him!  His  mouth  opens,  his  eyes  roll  and  his  hat 
whirls!  Because  of  the  complicated  gear  mechanism,  heretofore  possible  only  in  metal,  a  plastic  mate- 
rial was  needed  that  would  not  warp  because  it  was  dimensionally  stable  ...  a  material  that  would 
take  an  unbelievable  amount  of  abuse  because  of  its  high  resistance  to  impact.  Chemaco  Ethyl  Cellulose 
Molding  Powder  met  these  requirements  and  had  the  added  appeal  of  a  wide  range  of  permanent 
colors  that  would  not  chip  or  wash  off.  "Happo"  is  just  another  example  of  the  adaptability  of  Chemaco 
Ethyl  Cellulose  to  mass  production.  Full  information  about  Chemaco  Molding  Powders  for  injection  mold- 
ing and  extrusion,  including  Cellulose  Acetate  and  Polystyrene,  will  be  furnished  on  request. 


Ckewacc 


A     subsidiary     of     Manufacturers     Chemical     Cor  pcra  tier 

Berkeley   Heights,   N.   J. 

Branch  office   in  Cleveland 


JULY  1946 


PLASTICS 


45 


Presenting  a  number  of  designs  of  colorful  "Plaskon"  cellulose-filled  buttons  for  civilian  use 


Common,  ordinary  buttons  are  molded  by  the  millions  from 
alpha-cellulose  filled  "Melmac"  and  other  types  of  mela- 
mine  molding  compounds.  Below,  lightweight,  shatter  resist- 
ant tableware  of  "Plaskon"  melamine  used  on  Navy  ships 


pilling  machines.  In  molding,  the  pressures  required  are 
in  the  same  range  as  for  the  urea  materials.  It  is  possible 
to  use  temperatures  20°  to  30°  higher. 

Molding  compounds  using  fillers  other  than  alpha  cellu- 
lose are  also  rapidly  strengthening  their  [x>sition  in  the 
industry.  Consumer  and  industrial  requirements  for  mold- 
ing materials  which  will  provide  arc  resistance,  dielectric 
strength,  heat  resistance  and  resistance  to  shock  in  the 
finished  product,  have  been  responsible  for  this  trend.  Min- 
eral, chopped  cotton  cloth,  and  wotxl  flour  fillers  make  for 
melamine  molding  compounds  with  variable  electrical,  phys- 
ical, and  chemical  properties. 

Arc  resisfance  and  heat  resistance  are  the  keynotes 
the  success  of  the  mineral-filled  melamincs.  There  are  two 
types,  the  first  of  which  was  developed  as  a  high  heat  re- 
sistant material  possessing  good  arc  resistance  and  other 
electrical  properties.  When  formed  into  moldings,  the  ma- 
terial w  ill  withstand  heat  up  to  400°F. 

The  other  compound  involves  both  a  resin  and  filler  ad- 
justment. Some  heat  resistance  has  been  sacrificed,  al- 
though moldings  will  perform  well  in  service  up  to  .<IHI'|-' 
The  primary  reason  for  these  resin  and  filler  adjustments 
is  to  improve  mechanical  strength  and  dimensional  stability. 
This  particular  formulation  has  the  best  arc  resistance  ofj 
all  thermosetting  plastics,  molds  better  around  metal  inserts, 
and  with  its  excellent  electrical  properties  provides  a  gen-] 
eral  purpose  mineral-filled  molding  compound. 

Both  materials  are  available  in  a  wide  range  of  plastici- 
ties from  an  extremely  soft   flow,   satisfactory   for   under - 
pressured  molds  and  intricate  transfer  operations,  to  a  hard 
flow  suitable  for  rapid  production  of  small  or  thin  sectioned 
parts  by  the  compression  molding  technique.    It  is  interes 
ing  to  note  that  this  extremely  wide  flow   range  has  little  • 
no  effect  on  the  physical,  mechanical,  electrical,  or  rhi-iiiu-.il 
pro|>erties  ,,f  the  molded  article.    This  chaiacteristic  is  pai 
ticularly  true  of  its  shrinkage.    Throughout  the  flow   i.ing< 
the  shrinkage  difference  is  so  small  that  it  is  seldom  • 
sary    for   the   molder    to   concern    himself   about    shrinkage 
flow    during  the  design  of  the   mold. 

I'he  first  volume  application  fur  niinei  .1!  -filled  inclaniine 
molding  compositions  resulted  from  the  acute  nerd  •.,!  ,m 
unproved  dielectric  and  arc  resistant  material  felt  by  the 


46 


I'  I.  A  S  T 1 1  * 


JULY  1946 


Properties 


'Plaskon"  Melamine  and  "Melmac"  * 
(alpha  cellulose  filled) 


Value 


Specific  gravity 1-47 — 1.52 

Flexural  strength  (psi) 1  0,000—1  6,000 

Imooct  strength  (ft.-lb.  per  in.  of  notch — 

1 .,'  by  >  •/  notched  bar  bod) 0.24—0.35 

Rockwell  hardness Mil  8— Ml  22 

Water  absorption  I',    on  24  hr.  immersion) 0.10 — 0.6 

Arc  resistance  (unconditioned  test  specimen) 1  20 — 1  50 

Dielectric  strength,  short  rime,  '  $     thickness  (vpm) 300 — 400 

Dielectric  constant  (60  cycles) 7.9 — 9.5 

Power  factor  (60  cycles) 0.037—0.080 

"The  above  values  also  apply   essentially  for  alpha  cellulose   filled    Rejimene,  though 
here  are  variations    for  special  formulations. 


aircraft  ignition  manufacturers  when  the  military  aircraft 
tm  got  under  way.  Tests  indicated  that  .these  com- 
Is  ucmld  successfully  meet  the  particular  requirements, 
and  they  were  quickly  approved  for  their  purpose.  Many 
niolders  were  enlisted  to  carry  the  huge  production  hurden 
of  large  distributor  heads  and  many  other  ignition  moldings 
which  had  been  made  of  hard  rubber.  Finished  ignition 
parts  have  excellent  electrical  properties  as  high  tension 
insulator,  as  a  dielectric,  and  as  a  resistant  surface  to  elec- 
toral flash-over  and  tracking.  Seldom  does  a  surface  break- 
result  due  to  tracking  through  a  moist  deposit  of 
foreign  matter,  as  the  first  few  surges  of  current  usually 
dissipate  the  dampness  and  again  present  the  non-conducting 
pla-tics  surface  for  normal  function  as  an  insulating 
material. 

It  is  an  indication  of  the  tremendous  quantities  of  this 
material  used  during  the  war  that  ignition  systems  on  most 
combat  aircraft,  including  the  P-47,  P-51,  B-26.  B-25,  P-38 
and  B-29,  as  well  as  many  Naval  and  British  airplanes,  had 
melamine  components. 

Molders  of  mineral-filled  melamine  compounds  have  found 
that  many  jobs  required  a  special  molding  technique  in  order 
to  obtain  maximum  production  and  moldings  that  would 
pass  rigid  inspection.  Little  or  no  difficulty  is  experienced 
with  simple  compression  molded  parts.  But  the  majority  of 
aircraft  parts  were  of  a  most  complicated  nature,  and  trans- 
fer type  molding  was  found  most  satisfactory.  One  of  the 
advantages  is  that  it  prevents  insert  displacement  during  the 
molding  operation. 

The  technique  of  transfer  molding  complicated  ignition 
parts  required  much  in  the  way  of  experimentation  and  de- 
velopment by  the  niolders.  They  had  never  been  confronted 
with  such  parts  before,  and  they  had  to  work  out  methods 
of  gating,  mold  design,  and  other  problems.  The  problems 
were  solved,  and  the  improved  techniques  are  now  generally 
available  to  industry. 

The  rapid  advancement  in  the  science  of  preheating  from 
the  hot  plate  to  the  high  frequency  machine  has  done  much 
to  improve  the  moldability  of  mineral-filled  materials.  As 
much  as  three  pounds  of  general  purpose  material  can  be 
successfully  heated  to  the  consistency  of  putty  in  less  than 
a  minute. 

The  success  achieved  by  use  of  these  materials  on  combat 
aircraft  has  led  several  manufacturers  of  farm  equipment  to 
adopt  them  for  tractor  ignition  systems.  They  have  been 
very  well  .satisfied  with  performance  under  the  dusty  condi- 
tion- of  the  dry  cultivated  fields  and  operating  efficiency 
when  damp,  humid  environments  are  encountered.  New 
Use-,  are  continually  being  initiated  for  this  material  in  air- 
craft, automotive  and  tractor  ignition  parts,  and  in  electrical 
appliances,  for  such  uses  as  circuit  breakers,  terminal  blocks, 
and  industrial  controls. 

Chopped  cotton  fabric-filled  material  was  developed  and 
is  designed  for  consumer  and  industrial  applications  where 
resistance  to  shock  on  the  part  of  the  finished  product  is 
(Cottliiuied  on  page  76) 


Complicated  aircraft  engine  part  molded  from  mineral- 
filled  "Melmac"  possesses  good  electrical  properties 
and  high  heat  resistance.  Below,  insulating  section 
which  separates  the  two  metal  portions  of  brush  and 
stud'  holder  used  on  heavy-duty  electric  motors  is  made 
from  American  Cyanamid  Company's  rag-filled  "Melmac" 


JULY  1946 


PLASTtCS 


47 


I 


Uitwt  development  in  radios  at  Admiral  is  this 
large  radio  phonograph  cabinet,  which  is  com 
preeeion  molded  from  a  general-purpose  grade 
phenolic  molding  compound  by  Molded  Products 
Corp  .  Chicago.  It  comes  at  a  time  of  an  acute 
wood-veneer  shortage  in  the  radio  field.  Small 
radio  at  right  is  one  of  half  a  dozen  table  top 
models  now  being  made  with  plastics  cabinets 


V.  €.  QAi 

pfoif/cs    Attociat*    Editor 


Admiral  Uses 
More  Plastics 

New  radio,  refrigerator,  and 
range  models  emphasize  trend 
toward  plastics  auxiliary  parts 


ens 


RKI'KKSKNTA  I  IVK  of  a  general  industrial  trend- 
borne  out  by  many  recently-announced  applications 
— toward  an  increasing  use  of  plastics  accessory  and  auxil- 
iary parts,  the  1946  line  of  radios,  refrigerators,  and  ranges 
of  the  Admiral  Corp.,  Chicago,  contains  a  greater  number 
of  plastics  components  than  ever  before.  Perhaps  tit"  even 
greater  moment  is  the  matter-of-factness  with  which  a 
growing  number  of  engineers  have  come  to  regard  plastics 
in  these  uses,  suggesting  as  it  ,\.*--~  that  plastics  have  been 
M>  fully  accepted  that  their  entrance  into  new  fields,  or  their 
increased  use  in  old,  is  no  longer  a  cause  t'or  special  com- 
ment. 

Admiral's  uses  range  from  30  parts  in  three  refrigerator 
models  to  a  comparatively  inconsequential  role  in  kitchen 
ranges.    Radio  cabinets  <•. institute  a  volume  consumption  <>i 
plastics  which  will  increase  rapidly  once  radio  output  IM- 
Kins  to  -war  to  and  beyond  pre-war  levels 

New  Cabinet  Developed 

The  latest  development  in  radios  at  Admiral,  where  plas- 
tics made  their  initial  appearance  in  radio  cabinets  m 
1937,  U  a  plastics  cabinet  to  house  a  table  model  radio- 
phonograph,  along  with  a  somewhat  smaller  cabinet  for  a 
phonograph  •lone.  The  new  radio-phonograph  costs  the 
retail  buyer  approximately  20%  less  than  the  identical  in- 


strument  in  a  wood-veneer  cabinet,   the   saving   resulting 
from   the  existing  price  difference  between   plastu-s   and 
wood  veneer.    Furthermore,  the  new  cabinet  conies  at  a  I 
time  of  an  acute  wood-veneer  shortage. 

In  size  alone,  the  new  cabinet,  compression  molded  byl 
Molded  Products  Corp.,  Chicago,  in  a  400-ton  press,  is  an] 
innovation.  Measuring  16H"  by  \7%"  by  12",  it  is  said  by  I 
Admiral  to  be  much  larger  than  any  pre-war  plastics  ,al>-' 
inet.  Its  walls  are  3/16"  thick,  except  at  a  few  points  where] 
for  added  strength  they  are  7/16".  Four  brass  insei  • 
well  as  all  holes,  are  molded  in.  Preforms  of  the  general! 
grade  phenol  formaldehyde  molding  powder  used  for  the] 
ealiinet  are  preheated  in  an  RCA  IS  kw  electronic  pre-  • 
heater  to  insure  minimum  curing  time. 

Five  to  seven  minutes  are  said  to  complete  the  molding! 
cycle  from  the  time  the  plastics  blocks  are  preheated  and] 
placed  in  the  mold  until  the  rough  cabinet  comes  off  the 
highly  polished  steel  die.  Ten  minutes  complete  the  cool-J 
ing  process,  and  another  five  minutes  the  finishing  and] 
assembly  of  base  and  lid.  These  two  parts  are  molded  sep-j 
arately.  They  weigh  about  7'/i  Ib  and  3y£  Ib  respectively] 
for  the  radio-phonograph  housing  and  about  a  third  less] 
each  for  the  phonograph  cabinet  alone. 

An  interesting  point  alxmt  this  latter  piece  is  that  the] 
grille  is  molded  separately  ami  is  then  mounted  with  <ln\c  , 


Ifl 


.11  I.  Y   1946 


Helps  for  Draftsmen  and 
hints  for  Designers ...  in 


Mathematical  calculations  are  made  easily  and  accurately  on  this 

all  PLEXIGLAS  slide  rule,  with  graduations  and  numbers  molded  in. 

A  product  of  Perele.i  Hrothers.  Inc..  Milwaukee;  If  isc. 


PLEXICLAS  disks,  in  graduated  sizes,  simplify  the  drawing  of  lines 

parallel  to  a  splined  or  French  curve.  Developed  and  manufactured 

fry  Charles  A.  Jackson  of  Buffalo,  V.  V. 


transparent 

Plexiglas 


Many  designers  have  welcomed  the  use  of  the  all 
PLEXIGLAS  slide  rule  .  .  .  many  draftsmen  have 
welcomed  the  PLEXIGLAS  drawing  instruments  that 
simplify  and  speed  the  drawing  of  parallel  curved 
lines. 

Of  course,  these  are  articles  that  you  may  never 
encounter.  But  .  .  .  the  PLEXIGLAS  features  found 
in  these  instruments  may  spark  your  thinking  along 
new  design  lines. 

Take  transparency,  for  instance.  PLEXIGLAS  stays 
transparent — through  extremes  of  temperature — 
through  sun  and  rain. 

Light  in  weight,  yet  exceptionally  tough  and 
strong,  PLEXIGLAS  withstands  rough  handling  .  .  . 
resists  shattering. 

In  addition,  PLEXIGLAS  brings  to  all  applications 
the  feature  that,  more  than  any  other,  points  up 
sales  appeal — gem-like  sparkle! 

Start  your  thinking  along  PLEXIGLAS  lines  .  .  . 
our  technical  staff  will  be  glad  to  assist  you.  Phone 
or  write  our  nearest  office:  Philadelphia,  Detroit, 
Los  Angeles,  Chicago,  New  York.  Canadian  Dis- 
tributor: Hobbs  Class  Ltd.,  London,  Ont. 


Only  Rohm  and  Haas  makes 

Plexiglas 

crystal-clear  acrylic  plastic  sheets 
and  molding  powders 


PLEXIGLAS  is  a.  trade-mark,  Reg.  U.  S.  Pat.  Off. 


ROHM    &    HAAS    COMPANY 

WASHINGTON  S<?cM/?£.  PHILADELPHIA,  PA. 

Manufactuiers  of  Chemicals  including  Plastics  .  .  .'Synthetic  Insecticides .  .  .  Fungicides  .  .  .  Enzjmcs  .  .  .  Chemicals  lor  the  Leather.  Teitile  ind  other  Industries 


;  POLYSTYRENE 


The  Admiral  "Dual-Temp"  uses  31  oz  oi  polystyrene  in  temperature  control  knobs  and  estucheon.  double  freezing  locker  doors, 
vegetable  hydrator  front,  and  drip  tray  front;  13 '2  Lb  of  paper-based  phenolic  laminate  in  the  door  pan.  the  breaker  frame, 
and  (not  indicated)  the  divider  support  strip;  6'«  oz  of  acrylics  (not  shown)  in  nameplate  and  handle  trim;  and  an  ounce 
of  phenolic  in  two  freezing  locker  door  handles.  At  right,  the  "turn-table."  by  means  oi  a  rubber-covered  peg,  opens  the  poly- 
styrene freezing  locker  door  full  width:  then  a  2li  ounce  spring  slams  it  back  against  the  support  frame.  The  test  is  run  at 
the  rate  of  22  cycles  a  minute.  Door  shown  here  had  already  been  slammed  50.000  times  at  temperatures  down  to  minus  10°F 


.screws  to  complete  a  two-piece  assembly  (three,  counting 
the  lid). 

In  commenting  on  the  new  cabinet,  Ross  D.  Siragusa, 
president  of  Admiral,  said:  "Plastics  will  continue  to  gain 
popularity  lor  use  in  radio  In-cause  of  its  extreme  economy. 
In  onr  own  case,  the  new  cabinet  has  given  us  entry  with 
the  same  instrument  into  two  price  brackets.  That  i-  a 
distinct  marketing  advantage." 

I'.c-ides  the  new  model,  which  has  been  on  the  market 
only  a  v«ry  short  time,  about  a  half-do/en  other  table  top 
models  in  radios,  radio  phonographs,  and  phonographs  are 
available  in  plastics  cabinet-  out  "I  the  approximately  do/en 
and  a  half  models  to  which  the  company  i-  at  present  re- 
stricting production.  In  normal  pre-war  times,  many  more 
models  were  featured,  among  them  a  numlier  of  con-oles 
which  arc  not  back  in  production,  chiefly  Urau-e  of  the 
wood-veneer  shortage. 

Tin-  table  top  model-  currently  In-ing  produced  include 
the  6T01,  a  six-tulx-  model  with  an  ivory  or  mahogany  fin- 
ish cabinet  and  either  a  clear  cellulose  acetate  or  a  clear 
polystyrene  slide  rule  dial  assembly,  and  the  6'1'OJ,  a  five- 
mix-  model  with  choice  al-o  of  ivory  or  mahogany  cabinet. 
These  cabinets  are  compression  molded  by  Molded  I'rod- 
•  irp.,  of  a  general  -purpose  grade  phenol  formaldehyde, 
and  the  plastics  dial  assembly,  first  used  on  Admiral  radios 
in  I'M?,  i-  molded  by  the  Superior  Pla-tic  Co.  Model 
fiRIMH.  a  table  model  electric  phonograph,  is  also  being 
marketed  in  a  mahogany  tini-h  plastics  cabinet. 

Phonograph  needle-  .ire  individually  packaged  in  a  \»,\\ 
styrenc   container,   as   another   application   of   pla-tr 
Admiral. 

Admiral  officials  are  quick  to  admit  that  they  have  turned 


to  plastics  cabinets  not  only  Ix-causc  of  the  wood  shortage 
but  because  of  their  economy.  According  to  a  company 
statement  previously  referred  to,  the  use  of  plastics  make- 
possiblc  about  a  ~<^' ,  reduction  in  price  over  exactly  the 
same  instrument  in  a  wood-veneer  cabinet.  Thus,  the  6T05, 
which  in  a  wood-veneer  cabinet  sells  for  $39.95,  is  avail- 
able (as  the  6T01)  with  the  same  chassis,  but  with  a  plas- 
tics cabinet,  for  $27.95.  and  the  same  general  proportion 
holds  true  for  other  models  in  the  two  cabinet  styles 

Since  price  and  value  are  always  closely  associated  in 
the  mind  of  the  consumer,  it  is  easy  to  assume  that  tin- 
person  who  chooses  the  wood-veneer  cabinet  over  the  pla-- 
tics  at  the  lower  price  must  find  or  think  he  finds  qualities 
which  justify  the  higher  price.  That  sonic  buyers  attach 
more  value  to  the  wood- veneer  cabinet  is  accepted  if  so  facto 
by  Admiral  engineers,  and  they  are  not  too  much  interested 
at  present  in  learning  whether  the  preference  for  «• 
scientifically  justified.  Many  buyers  believe,  perhaps  in- 
correctly, that  wood  ha-  a  In-tter  acoustical  quality  than 
plastics  and  thus  gives  a  richness  of  tone  unobtainable  with 
the  latter. 

Refrigerators 

Turning  from  radios  to  refrigerators,  three  model-  of 
the  latter  are  being  manufactured,  though  not  yet  in  quan- 
tity, (if  these  three — the  Master,  the  De  I.uxe,  and  the 
nuaI-Trmf> — it  is  interesting  to  note  that  the  super  deluxe 
model,  the  /'ual-Temf.  uses  more  pla-tics  |>arts  than  the 
Dt  I.uxt,  and  it  in  turn  more  than  the  Master,  or  standard 

model. 

In  bulk  weight  of  plastics,  the  three  models  use  re 

i  (  cnlniiifii  t>H  pa;/. 


JULY  194fi 


yov 


«£*" 


<££ 

•es^ 


., 


\Vk&$m 

when  Jim  asked  me  that! 

I  was  buying  that  resin.  He  was  responsible  for  making 
it  work.  I  didn't  know  that  we  could  have  a  resin  made 
to  order  for  our  specific  job,  instead  of  a  resin  made  to 
the  average  requirements  of  merely,  similar  applica- 
tions. That's  when  I  switched  to  Interlake  specifica- 
tion resins. 

*         *         * 

Interlake  has  eliminated  "resin  adjusting,"  cut  costs,  and 
speeded  production  for  users  of  resins  in  many  fields — 
because  Interlake  makes  each  resin  to  fit  the  user's  specific 
application.  That's  why  we  call  them  specification  resins. 

Interlake  functionally  engineers  a  resin  to  the  user's  indi- 
vidual job — in  the  user's  plant — tests  it  on  the  job — then 
stabilizes  production  of  that  resin  for  continuous  uniformity  in 
performance.  Thereafter,  the  performance  of  every  shipment 
of  that  resin  is  identical  with  the  first. 


P, 

' 

I 


BRING  YOUR  RESIN  PROBLEMS  TO  INTERLAKE, 
draw  freely  upon  (he  wide  experience  of  our 
research  staff.  We  will  gladly  work  with  you 
on  any  resin  problem,  or  discuss  with  you  the 
possible  advantage  of  using  resins  in  any  opera- 
tion or  process.  Write  Interlake  Chemical 
Corporation,  Plastics  Division,  1935  Union 
Commerce  Building,  Cleveland  14,  Ohio. 


JULY  194G 


lYIIKIAKI 

CHEMICAL 

Corporation 

•PRODUCTS     FROM     COAL- 


PLASTICS 


51 


Setting  knockout  pins  for  a  24-cavity  mold  at  Cruver  Mfg.  Co..  Chicago 


Injection  Mold  Design 

Part  III.    A  detailed  discussion  of  problems  involved  in  choosing 
cavity  layout  pattern,  parting;  line  location  and  ejection  methods 


tf  (7°'tn 


From  the  standpoint  of  gating,  the  circular  layout  (  Fig.4a) 
is  often  to  be  preferred  on  molds  of  a  few  cavities,  as  direct 
sprue  to  cavity  runners  can  be  used.  The  layout  is  usually 
employed  on  heavy  sections  such  as  acrylic  hairbrush  han- 
dles, and  on  lenses,  where  gating  is  extremely  important. 
However,  on  the  greater  portion  of  jobs  this  direct  gating 
is  not  necessary,  and  other  considerations  will  govern  the 
selection. 

The  most  commonly  used  pattern  is  that  with  two  parallel 
rows  of  cavities  (Fig.  4b).  This  layout,  using  a  single  run 
ner  down  the  center  of  the  die  and  smaller  runners  Icadnm 
to  the  individual  cavities,  lias  many  adx.tnt.iges.  First,  the 
knockout  pins  are  in  two  long  rows  near  the  ccnterline  of 
the  die,  which  permits  a  narrow  knockout  plate,  and  thus 
gives  a  well  supported  die  on  the  ejector  half.  Also  tin- 
layout  makes  possible  a  simple  yet  uniform  system  of  cool- 
ing channels  in  the  mold  and  a  system  of  gating  that  is  not 


too  complex  to  permit  the  use  of  a  clipping  fixture  for] 
trimming  the  gates.  It  is  the  most  <lesirahle  form  unles 
the  cavities  are  so  numerous  as  to  make  the  die  too  long  t 
fit  into  the  machine,  and  it  is  the  only  practical  layout  fo 
use  with  cavities  which  require  automatic  side  pulls  to  mo1< 
side  holes  or  undercuts. 

When  there  are  too  many  cavities  for  this  layout,  one  of 
the  layouts  shown  in  Fig.  4c  or  Fig.  4d  should  be  used. 
>ome  designers  favor  the  cross  layout  t  Fig.  4c  i  U- 
it  gives  a  more  direct  system  of  runners  to  distribute  the! 
material  to  the  various  cavities.  However,  tx-cause  it  spreads 
the  area  in  which  the  knockout  pins  are  located,  a  wide 
knockout  plate  is  required,  and  the  problem  of  furnishing 
proper  support  for  the  ejector  half  is  greater.  Also,  this 
w  ide  knockout  plate  may  give  trouble  by  becoming  cocked! 
as  it  moves  forward,  thus  breaking  small  pins  and  necessi- 
tating die  repairs.  This  is  especially  true  on  dies  being 
on  machines  with  one  or  two  knockout  stops.  This  cro 
la\out  also  requires  a  rather  complicated  system  of  coolir 
channels  to  assure  uniform  cooling  to  all  cavil 

1  he  four  row  layout  (Fig.  4d),  with  runners  down  IK-- 
OH  page  55) 


52 


p  !..%.«  fir  K 


JULY   1946 


•  * 


- 


Canadian  A&ent. 


They're  buying  LESTERS  in  the  Mid-West 
where  production  ie<zit<t  counts 


\, 


•  Wherever  plastics  are  molded  for 
refrigerators,  automobiles,  airplanes, 
appliances— the  big  mid-west  com- 
petitive jobs  where  top  production  is 
a  "must" — they're  buying  new  Lesters. 


MMMM  CITY 

*T   LOUIS! 


CHICAGO-, 


AURORA 


BAY  CITY  J/*\ 
OfXTIK      \ 

'*  HARBOR  OITRC 

•JTOLIDO 

"^" 


RICHMOND 


PORTLAND 


MIDOLtFlflO 

DAYTON       . 

CAMDRIVCE 


There's  a  reason:  The  new  Lester  Injection 
Molding  Machines  were  deliberately  de- 
signed and  built  to  smash  old  production 
records — and  make  new  ones  .  .  .  They're 
molder's  machines— these  new  Lesters  — 
with  new  exclusive  features  developed  to 
meet  the  specific  demands  of  America's 
best  injection  molders. 


And  as  for  references:  Inquire  in  the  mid- 
west plastic  shops  where  men  who  know 
injection  molding  will  tell  you,  "If  it's 
the  best  in  molding  you're  after — and  if 
production  really  counts  —  see  the  new 
Lesters  before  you  buy,  and  check  into  6 
of  the  many  exclusive  features  of  the  new 
Lester  models." 


6  Exclusive  Lester  Features 

•  Vertical  injection  cylinder,  tolld  plunger  and  Inter- 
sally  heated  torpedo  plaitleliei  material  lalter. 

•  One-piece,  cait  alloy  ateel  iclid  Irame  lor  perfect 
llaih-lree  molding!. 

•  Improved  toggle  linkage  glret  lour  metal-to-metal  col- 
umns to  lupport  cloted  mold  agalnat  Injection  prenur*. 

•  Larger  die  height  adjusting  tcrew  with  tingle  hand 
crank  adjustment. 

•  Automatic,  hydraulic  ejection  alter  mold  It  open  on 
10,  24  and  32  01.  modelt. 

•  Safety  gate  It  Interlocked  hydraullcally.  electrically 
and  mechanically. 


,  ,  ,  for  details  and  specifications  of  the  new 
Lesters  from  4  to  32  ounce  capacity. 


New  Lester 
Model  L-2K-8 
8  Ounce  Capacity 


INJECTION   MOLDING    MACHINES 


D,.ir,-b«f.d  by  LESTER- PHOENIX,  INC. 

2711    CHURCH    AVE..   CLEVELAND   13,    OHIO 


twivti  the  two  outside  rows,  gives  a  more  compact  die  at 
very  little  sacrifice  in  the  material  flow  to  the  cavities,  and 
is  very  commonly  used  on  larger  dies. 

After  the  designer  has  determined  the  number  of  cavi- 
ties, type  of  construction  and  the  best  pattern  of  cavity  lay- 
nut,  lie  is  ready  to  begin  the  mold  drawing.  His  first  step 
will  be  to  determine  the  proper  location  of  the  parting  line 
on  the  molded  piece.  On  some  pieces  there  is  only  one 
p.-sible  location,  but  often  the  selection  of  the  proper  part- 
ing line  involves  several  considerations.  Before  discussing 
this  problem,  we  will  look  into  these  various  factors,  all  of 
•  which  should  be  understood  in  order  to  make  a  wise  selec- 
tion of  parting  line  location. 

Ejecting  the  Casting 

The  casting  will  have  to  be  ejected,  and  here  is  another 
problem  of  mold  design.  The  most  common  method  of 
ejecting  moldings  is  the  knockout  pin.  Since  it  leaves  marks 
on  the  molded  piece,  it  should  be  placed  on  non-appearance 
surfaces  whenever  possible.  The  cavity  can  be  dug  into 
either  half  of  the  injection  mold.  Ejection  of  the  piece  is 
the  only  consideration  that  determines  in  which  half  it  will 
be.  The  outside  of  the  piece  is  usually  the  appearance  sur- 
face; therefore  we  usually  find  the  cavity  in  the  injection 
half  of  the  mold,  and  knockout  pins  in  the  punch,  which  is 
on  the  moving  half. 

Sometimes  piece  design  is  such  that  the  molding  cannot 
be  made  to  stick  on  the  punch.  Then  we  must  design  the 
mold  with  the  cavity  in  the  ejector  half,  and  knock  the  piece 
out  of  it.  Knockout  pin  marks  will  then  have  to  be  buffed 
off  the  appearance  surface  if  they  are  considered  objection- 
able. Often  the  pins  can  be  camouflaged  by  some  decorative 
design  so  that  the  marks  left  by  them  appear  to  be  part  of 
the  piece. 

This  matter  of  ejection  is  extremely  important.  The  de- 
signer must  know  whether  the  piece  will  stick  in  the  cavity 
or  on  the  punch.  If  he  is  in  doubt,  he  must  design  into  the 
mold  some  feature  such  as  reverse  draft  or  undercuts  in 
order  to  make  the  piece  stay  in  whichever  part  he  designs 
into  the  ejector  half  of  the  mold. 

Avoid  Small  Knockout  Pins 

Quick  ejection  is  necessary  for  good  production,  and 
knockout  pins  should  be  of  sufficient  size  and  quantity  to  do 
the  job  without  an  unduly  long  setting  up  time.  Small  knock- 
out pins  are  not  good  design  if  they  can  possibly  be  avoided, 
for  they  tend  to  press  into  the  molding,  and  are  also  more 
likely  to  break  in  service  than  larger  ones.  Pins  under  %G" 
may  lead  to  trouble,  and  a  J4"  minimum  is  desirable. 

Stripper  plate  construction  (Fig.  5)  is  usually  desirable 
to  knock  out  pins  where  the  design  of  the  piece  makes  its 


JULY  1946 


I'LASTMCS 


Side  view  of  stnpper  plate  mold  (above),  end  view  (lower  left),  and  plan  view  (lower  right) 


use  possible,  as  ejection  can  be  obtained  with  k"-s  danger 
of  warping.  By  eliminating  thi>  danger  and  the  one  of 
pushed-through  pins,  the  cycle  can  be  s|x'oded  up  to  give 
substantially  better  and  taster  production.  Thi>  u>ually  over- 
comes the  additional  cost  common  on  >tri|>)H-r  plate  dies. 
The  plate  is  stripped  by  the  action  of  four  or  more  pin>  ex- 
tending from  the  knockout  bar  to  tin-  >tripper  plate.  This 
plate  slides  on  the  guide  pins  which  are  pir^cil  in  the  mov- 
ing half  of  the  die.  Stripper  bolts  or  -onu-  other  type  of 
(Continued  on  page  77  i 


56 


PLASTICS 


JULY  1946 


...ON  THE  NEW  POWER-OPERATED 


PLASTICS  INJECTION  PRESS 

This  1  oz.  molder,  powered  by  a  2  hp  motor,  is  hydraulically 
operated  for  economical  production.  •  Automatic  tempera- 
ture control,  automatic  parts  ejection,  simple  operation  and 
low  cost  are  a  few  of  the  advantages  of  the  H-200  Press. 
Write  for  the  free  bulletin  shown  above. 


2683    EA 


•Ui 

ST    79TH 


STREET 


CLEVELAND    4,     OHIO 


JULY  1946 


f'f.ASTICS 


57 


Building  Better  Kitchen 


Durability,    as    well    as    serviceability,    is    built 
into  the  ethyl  cellulose-aluminum  sink  strainer 


IT  IS  no  secret  and  surely  tm  new-,  to  anyone  in  the  imlu— 
try  that  there  has  been  a  definite  amount  of  misapplica- 
tion of  plastics  in  manufacture — that  is.  certain  plastics 
used  for  purposes  to  which  they  were  not  fitted,  with  eon- 
-ei|iient  failure  to  "stand  up"  under  us<-. 

Without  going  into  details  of  the  reasons  for  such  mis- 
application,  let  us  say  al>o  that  there's  no  secret  about  the 
fact  that  this  has  inevitably  led  to  dissatisfaction  on  the  part 
of  the  ultimate  consumer.  It  was  probably  unavoidable  that 
with  shortages  of  various  plastics,  and  last-minute  substitu- 
tions having  to  be  made  at  times,  there  would  lie  some 
misapplication  of  plastics  in  consumer  goods  during  the  war 
years.  The  consumer,  however,  after  one  or  two  experiences 
with  plastics  products  that  fail  to  conform  to  reasonable 
expectations,  is  more  than  likely  to  conclude  that  HO  plastics 
product  is  reliable. 

Unsatisfactory1  accessories  and  utensils  for  the  kitchen 
have  been  among  the  first  to  receive  such  condemnation. 
To  the  housewife,  "plastics"  usually  means  a  colorful,  light- 
weight material,  smooth  and  pleasant  to  the  touch,  and  an 
attractive  addition  to  her  kitchenware.  Its  actual  type,  com- 
position, thermosetting  or  thermoplastic  pro]K-rties.  dimen- 
sional stability,  resistance  to  heat,  acids,  etc. — none  of  this 
means  anything  to  her  as  an  average  consumer. 

Here  is  where  an  informative  labeling  program,  such  as 
that  launched  by  the  SIM.  provides  an  excellent  method  of 
supplying  consumers  and  salespeople  with  requisite  infor- 
mation as  to  the  potentialities  and  limitations  of  the  plastics 
item  purchased. 

Certain  manufacturers.  distiirlx.-d  by  the  fact  that  plastics 
in  general  were  being  denounced  by  disgruntled  users  of 
some  items,  decided  that  something  should  be  done  about 
the  situation.  Among  these  manufacturers  \\as  Plastic 
Metal  Mfg.  Co.,  Chicago,  which  designs  and  makes  various 
household  utilities.  As  a  result  of  its  decision,  tins  company 
has  developed  a  line  of  plastics  accessories  for  the  kitchen. 


Polystyrene  I*  combined  with  rustproof  metal  mesh  In  on  attractive  and  useful  accessory  lor  the  modern  kitchen 

,s  !•  I.  \STI1  -S  JULY   1946 


.    CLurcL 

plastics  Associate  Editor 


Improved  design,  and  correct  choice  of  plastics 
suitable  to  application,  meet  demand  for  kitchen 
utensils  that  will  "stand  up"  under  every  day  use 


embodying  principles  of  design  and  construction,  as  well  as 
choice  of  materials,  to  insure  their  meeting  normal  require- 
ments of  kitchen  use. 

One  of  the  first  considerations  of  the  company  in  pro- 
ducing this  line  was  strainers — sink  strainers,  tea  strainers, 
etc.  Mindful  of  the  instances  where  all-plastics  strainers 
had  buckled,  warped,  and  been  rendered  useless  by  house- 
wives pouring  boiling  or  extremely  hot  fluids  through  them, 
the  Plastic  Metal  Mfg.  Company's  new  strainers  combine 
the  colorful  and  other  desirable  qualities  of  plastics  with  the 
higher  heat-resistant  properties  of  metal  in  the  actual 
strainer  portion  of  these  products.  Richard  C.  Helfenbein. 
president  and  chief  designer  of  the  company,  and  W.  C.  P. 
Zabel,  its  general  sales  manager,  worked  intensively  on  the 
project,  testing  and  rejecting  many  designs  before  they 
evolved  models  which  they  considered  satisfactory.  Price 
must  be  a  consideration  to  the  housewife  in  average  circum- 
stances, and  the  strainers  which  were  finally  produced  as  a 
result  of  the  company's  planning  are  sold  at  very  little  more 
than  the  all-plastics  strainers  which  had  not  been  satis- 
factory. 

After  experimentation,  ethyl  cellulose  was  decided  upon 
as  the  most  suitable  medium  for  the  company's  purpose, 
in  production  of  its  sink  strainers.  The  body  of  the  strainer 
is  injection  molded  of  Dow  Ethoccl,  with  the  strainer  por- 
tion, at  bottom,  of  a  stainless  type  aluminum  which  is  joined 
to  the  body  in  the  molding  operation,  thus  becoming  an 
integral  part  of  the  product.  One  of  the  major  problems 
encountered  was  that  of  accurate  positioning  of  the  metal 
and  assurance  of  equal  distribution  of  the  plastics  material 
on  both  upper  and  lower  edge,  as  required.  Study  and 
experimentation  by  Mr.  Helfenbein  and  Mr.  Zabel  solved 
this  problem  with  specially  designed,  patented  dies  that 
counteract  the  natural  tendency  of  the  metal  (being  heavier 
than  the  plastics)  to  shift,  and  would  hold  it  firmly  in 
place  during  the  molding.  Available  at  present  in  ivory- 


white,  red,  or  green,  the  sink  strainer  sells  for  only  490,  and 
attractively  fills  a  kitchen  need. 

All-plastics  tea  strainers  constituted  another  item  which 
had  all  too  often  proved  unsatisfactory  in  use.  A  tea  strainer 
that  would  "stand  up"  under  normal  usage,  and  perform  the 
function  for  which  it  was  intended,  was  part  of  the  Plastic 
Metal  Mfg.  Co.'s  program.  Experimentation  and,  rejection 
of  design  and  material  for  the  purpose  resulted  in  a  tea 
strainer  which  combines  polystyrene  with  chromeplated  wire 
mesh  in' an  efficient  and  good-looking  product.  The  rust- 
proof mesh  through  which  the  boiling  water  is  to  be  poured 
is,  like  the  metal  portion  of  the  sink  strainer,  molded  into 
the  rim  and  is  so  shaped  as  to  eliminate  the  frequently 
exhibited  tendency  of  wire  mesh  to  bulge.  Dow  Styron,  in 
clear  or  red,  is  used  to  make  these  strainers,  which  sell 
for  15*. 

Another  extremely  handy  strainer  is  made  by  this  com- 
pany— an  item  which  would  immediately  recommend  itself 
to  any  woman  who  has  ever  had  occasion  to  strain  any 
liquid  through  a  funnel  into  a  bottle  or  other  small-mouthed 
{Continued  on  page  98) 


THIS    PLASMETL 
SINK    STRAINER    MADE   OF    "ETHOCEL' 

(o  product  of  Dow  Chemical  Company) 

odorleis   and   acid    resistant,    will   not   shatter  or   chip,    nor 
hot  water  affect   it  under   normal   usage.      The  patented 
construction  prevents  the  RUSTPROOF  GENUINE 

ALUMINUM   BOTTOM   from   ever    becoming 
V  •  detached. 

I  RUSTPROOF  DURAtlf  SANITARY 


nfgstif  meted  mfy.  ce. 


4541-49   W.   Diver. ey    Ave. 
CHICAGO   3*.   ILL. 


This  modern  Plasmetal  Tea 
Strainer  is  made  of  "STYRON" 

(a  product  of  Dow  Chemical  Co  I 

the  finest  plastic  material,  odor- 
less and  acid  resistant,  will  not 
shatter  or  chip,  nor  will  it  be  af- 
fected by  hot  tea  or  coffee  under 
normal  usage.  The  patented  con- 
struction of  this  strainer  prevents 
the  RUSTPROOF  fine  wire  mesh 
screen-from  ever  becoming 
detached. 

RUSTPROOF  .  .  DURABLE  .  . 
SANITARY 

plastit?  mtteJi  mfy  e«.  , 

4541.49   W.    Diver.ey    Ay, 
CHICAGO    1°,    III. 


Handy  strainer  fits  both  funnels,  remains  in  place  during  use 

JULY  1946  PLASTICS 


Informative  labels  are  helpful 
to  seller  as  well  as  purchaser 


Ac    ivory -c  •  pi«c«    cn*« 

is    injection    mold*d 

PUxsrtics   Divuion   to   tmctoo*   Wai 

Co-'s 

Design  of 

timepiece   das- 


swcslter  with  reo 

handle  in  choice  o 

1 

s*j  perfume  as  the  swa 
by    Plastic 


w,.a?K>n    ot    c  ear    polystyrene    dome    and 
blade,    blue,    yr*wn    at    while    cdltu 
acetate    biwiyiraie     makes    an     attraciive 
iy   holder  for   toothbrushes.     It   is  molded 
did    merchandised    by    Standard    Products    Co. 


PATENTS 


American  manufacturers  are  now  being  offered  patents  of  our  war-time 
enemieSf  which  include  many  in  field  of  plastics  processing 


A'PROXIMATELY  45,000  patents  held  hy  persons  or 
corporations  of  enemy  countries  during  the  war,  are 
waiting  for  takers  at  the  Office  of  Alien  Property  <  us 
todian.  1,771  of  these  are  in  the  field  of  plastics  manufac- 
ture, fabrication  and  coating,  while  several  thousand  others 
are  available  in  such  other  fields  as  Amusement  Devices 
and  Toys,  Baggage,  Buckles  and  Buttons,  Jewelry,  Kitchen 
and  Table  Articles,  etc.,  which  should  prove  of  great  value 
and  interest,  particularly  to  end-users. 

Although  none  are  for  sale,  most  of  the  Custodian's 
vested  patents  are  now  available  for  use  under  Dimple  li- 
censing terms.  Enemy  patents,  unless  already  exclusively 
licensed  to  American  interests  prior  to  vesting,  are  being 
licensed  to  any  manufacturer  on  a  non-exclusive,  royalty- 
free  basis  for  the  life  of  the  patent.  Other  patents,  vested 
from  nationals  of  enemy-occupied  countries  and  not  pre- 
viously licensed  to  American  interests,  are  to  be  licensed 
for  the  life  of  the  patent  on  a  reasonable  royalties  basis.  A 
licensing  fee  of  $15  per  patent — an  administrative  charge 
and  not  a  royalty  —  is  required  for  each  patent  license 
granted. 

l<>  make  these  patents  available  to  every  manufacturer 
in  the  country,  the  Office  of  Alien  Property  Custodian  has 
prepared  three  types  of  publications:  Classified  Lists,  which 
give  patent  numbers  and  titles  of  inventions,  according  to 
the  Patent  <  >tYice  system  of  classification;  Abstracts,  which 
furnish  brief  technical  descriptions  of  vested  patents ;  and 
(  lifinicat  Abstracts,  which  were  prepared  as  a  convenience 
to  chemists  and  business  men  to  minimize  searching  time, 
rust  and  delays  in  ordering  copies  of  patents  in  their  pre- 
liminary studies  for  interesting  vested  patents.  Information 
regarding  all  of  these  publications,  together  with  an  Index 
to  the  offerings,  may  be  obtained  by  writing  the  Alien 
Pro|H-rty  (  tistodian,  Field  Building,  Chicago  3,  Illinois. 

Listed  below  are  some  examples  of  patents  in  which 
readers  of  plo»t/e»  nlay  be  interested : 

AP(  268,117  —  Articles  Molded  From  Synthetic  Resin. 
Walter  F.ngel.  I-ile.]  April  15.  1939.  A  method  of  producing 
plastics  articles  hy  hot-press  molding.  Such  moldings  are 
suitable  for  use  as  bearings,  filters  and  commutators  for 
electrical  machines. 

A  PC  .73,414— Mono/Us  of  Synthetic  Resins.  F.mil  Hu- 
bert and  Herbert  Rein.  Filed  May  13,  193°.  This  patent 
deals  with  the  manufacture  of  artificial  liru-h  and  broom 
bristles,  superior  in  n  -stance  to  water,  alkali,  acids  and 
bacteria. 

A  PC  285,944—  Method  and  Means  for  tin-  Pniduclwn  <>j 
Ornamentiil  Scrctnlike  Material.  Daniel  Swamv-ki.  Filed 
July  12.  l''.V.  A  method  and  device  for  making  ta|>es, 
chains,  or  tin-  like,  consisting  of  plastics  materials  of  cir- 
cular or  disk  shaped  designs,  held  together  hy  threads. 
\\irrs.  or  wrhliing.  Products  are  useful  in  trimming  dresses,- 
nuking  luggage,  etc. 


APC  286,693—  Method  for  the  .Manufacture  of  H'riting 
Masses.  Henrich  Schw  appacher.  Filed  July  26,  1939.  1  his 
patent  show  s  how  water-insensitive  plastics  pencil  leads  and 
drawing  and  marking  chalk  can  be  made. 

APC  348,683 — Process  for  the  Production  of  Synthetit 
Linear  Condensation  Polyatnides.  Paul  Schlack.  Filed  July 
31,  1940.  For  filaments,  ribbons,  foils,  castings,  sprayed  and 
pressed  products. 

APC  355,455— Process  for  the  Manufacture  of  Hydrot 
pliilic  Polymerization  I'roducts  of  the  Superpolyaniide  Type. 
Max  Hagedorn.  Filed  September  5,  1940.  Product 
duced  through  this  process  may  be  used  as  thickening  agents 
for  printing  pastes,  sizing,  etc.,  and  as  photographic  gelatin 
substitutes. 

APC  364,334 — Interpolyamides.  Emil  Hubert  and  Her- 
mann Ludewig.  Filed  November  4,  1940.  Useful  in  the 
manufacture  of  adhesives.  artificial  leather,  laminated  arti- 
cles, films,  foils,  coatings  and  impregnating  compounds. 

APC  374,597  —  Optical  Element.  Herre  Rinia.  Filed 
January  15,  1941.  A  method  for  preparing  lenses  from 
gelatiuizahle  materials.  Shrinkage  may  IK-  determined  !*•- 
forehand,  resulting  in  the  formation  of  an  accurate  lens. 

APC  393,282— Process  for  the  Production  of  O*alkyla~ 
tion  Products.  Heinrich  Hopff,  Wilhelm  Muenster  and  J 
sef  Stadler.  Filed  May  13,  1941.  A  method  useful  in  the 
manufacture  of  softeners  for  plastics,  films  and  water- 
sensitive  cellulose  materials,  and  finishing.  >i/.ing.  dispersing 
or  impregnating  agents. 

APC  404,514 — Polyvinyl  Chloride  Compositwi 
rich  Maiu-hen  and  Willie  Schmidt.    Filed  July  29,  1941.    A 
process  which  can  be  useful  in  the  manufacture  of  extruded^ 
>-;tst  and  molded  articles,  adhesives.  coatings,  films,  foils 
safety  glass  and  artificial  leather. 

1,881,248  —  Mold  for  Manufacturing  Boots,  Shoes  ,;m/ 
Similar  Articles  of  Rubber  or  Other  Plastics  Materials. 
Hector  Steppe,  et  al.  A  mold  for  rubber  or  plastics  bouts 
and  the  like,  comprising  a  core,  a  base  element  for  shaping,' 
the  sole  and  the  heel,  a  crescent-shaped  side  element  for 
shaping  a  narrow  strip  of  the  upper  adjacent  the  heel,  and 
a  cup-shaped  cover  engaging  the  core  and  shaping  the  iest 
of  the  upper. 

1,983,035  —  Means  for  Manufacturing  Brush   Handles. 
Riichiro  I/awa,  Japan.  Application  August  31,  1933,  Serial 
No.  687,578.  A  device  for  forming  brush  backs,  comprising 
a   pair  of  die-blocks  having  complementary  grooves  coJ 
acting  to  form  a  mold. 

2,043,503 — Device  for  Producing  Plastics  Reproductions! 
of  Corporeal  l-'orms.    Helmet  Aschenborn,  Germany.     \p- 
plication  February  o,  1936.     A  device  for  making  plastics 
reproductions  of  statuettes,  particularly  busts.   May  also  be! 
used  to  reproduce  the  heads  of  living  or  dead  people. 

-'.1(11.540     rr,><;-ss  for  Producing  ArticUs  from  Mol 
•  •tiHiifd  on  page  98) 


PLASTiCS 


JULY  1946 


Curing  time  on  this 
steam  meter  case 
was  reduced  up  to 
55%  with  Federal's 
Megatherm. 


FOR 


LARGE  PARTS 

OR  SMALL 


/  /  / 

heating*  preforms  with  MEGATHERM 

*f     1*1  /  /  Reg.  U.  S.  Pot.  Off. 

is  uniform  ...and  fast! 


Heating  plastic  materials  prior  to  mold- 
ing is  a  job  for  Federal's  Megatherm. 
Because  it  does  it  dielectrically — there- 
fore uniformly.  And  with  its  wide 
voltage  range,  accommodates  a  wide 
variety  of  preform  sizes — powdered 
plastics,  too — with  the  best  voltage- 
per-inch  for  the  substance.  Coupled 
with  high-frequency  operation,  this 
means  speed  heating! 

Take  the  experience  of  the  Watertown 
Manufacturing  Company  of  Water- 
town,  Connecticut,  for  example.  Using 
Neillite,  their  own  plastic  material,  cur- 


ing time  on  the  flat-iron  handle  shown 
here  was-  cut  25%.  For  the  large, 
compression-molded  meter  case,  cur- 
ing time  was  reduced  up  to  55%. 
What's  more,  with  Megatherm  heating, 
the  case  was  molded  in  a  smaller  press 
than  normally  used! 

Uniform  heating  with  Megatherm 
means  uniformly  excellent  plasticity  in 
preforms  .  .  .  results  in  lower  molding 
pressure  requirements,  in  easier  flow  to 
all  recesses  of  mold  .  .  .  saves  dies  .  .  . 
permits  complex  parts  to  be  processed 
with  precision.  Write  for_ details. 


Curing  time  on  this  new 
type  Manning-Bowman 
"swivel  action"  flat-iron 
handle  was  reduced  25% 
with  Federal's  Megatherm. 


Federal  Telephone  and  Radio  Corporation 

*  *>^  /^SSx 


Export  Distributor: 

International  Standard  E/ecfric  Corporation 


Newark  1,  New  Jersey 


JULY  1946 


i»LASTMCS 


63 


An  Interpretative  Survey  of 

German  Plastics  Fabrication 

Part  IV.  How  the  Germans  spun  fibers  from  the  polyamides  and  from 
poly-vinyl  chloride  by  an  extensive  variety  of  interesting  processes 


Molded  beauty  ol  polystyrene  radio  speaker  housing  shows 
high    quality   of    workmanship    (Capt.    Nalle-SPI    collection; 


W.   C. 


Men«g«r,    PUttict   Development    Division 
The  Dow  Chemicel  Company 

THE  Plastics  Team  of  the  Quartermaster  Corps  was  not 
much  interested  in  the  fabrication  <>r  u-rx  of  synthetic 
fiber,  since  this  work  was  l>eing  thoroughly  investigated  by 
the  Fiber  and  Textile  Teams.  There  were.  howi  -MT.  -everal 
instances  where  the  pr<Mltu-tion  of  certain  synthetic  fibers 
was  so  closely  tin  I  up  with  plastics  production  that  a  brief 
investigation  was  deemed  advisable.  The  materials  covered 
included  after-chlorinated  polyvinyl  chloride,  certain  of  the 
polyamides,  ami  polyvinyl  chloride,  on  which  some  experi- 
mental work  had  been  done. 

(  hlorinated  polyvinyl  chloride  was  made  by  treating 
polyvinyl  chloride  in  a  proper  solution  with  chlorine  In 
this  way  it  was  possible  to  raise  the  chlorine-content  of  the 
irom  some  :•>>'',  to  M'l  .  From  the  standpoint  of 
fiber  production  by  solvent  methods,  this  change  was  de- 
sirable. Chlorinated  polyvinyl  chloride  was  somewhat  more 
soluble  in  certain  solvent,  tli.m  polyvinyl  chloride.  Further, 


til 


its  increase  in  chloride  content  raised  its  softening  point 
above  that  of  polyvinyl  chloride.  Chlorinated  polyvinyl 
chloride  was  generally  stabilized  with  .5%  of  dioxy  diethyl 
stiltide.  It  was  dissolved  in  very  anhydrous  acetone  to  a 
honey-like  M.lution  in  15<H>-gallon  paddle-agitated, 
jacketed  kettles  at  40°C  (104°F)  finishing  temperature.  It 
was  tillered  twice  in  alloy-covered  plate  :md  frame  filters 
with  cntton-vistra-linen  cloths.  It  was  then  expressed  from 
solution  tanks  at  2l/2  atmospheres  and  pumped  with  bnm/e 
pumps. 

De-aeration  for  24  to  36  hr  standing  warm  at  jacketed 
temperatures  was  desirable.  In  this  form  the  material  was 
sensitive  to  decomposition  by  iron. 

Chlorinated  polyvinyl  chloride  was  spun  on  two  tyjx-s  of 
machines  for  the  production  of  ( 1 )  continuous  filter  and 
i  _'  i  cut-crimped  fiber.  The  economical  reco\ery  of  acetone 
from  the  first  process  (4%)  depended  on  large  \olnme  of 
richer  mixture  (13%)  from  the  second  process.  There  was 
no  vapor  recovery,  but  the  over-all  acetone  lo->  was  only 

For  continuous  liiVr  the  c<x>1ed  solution  was  gear-pumped 
to  spinnerettes  (120  holes)  which  spun  upward  through  a  4 
cm.  2.3  meter  high,  water-filled  glass  tube.  In  threading. 
the  initial  lilx-r  was  Mashed  up  the  tulx-  with  water,  and  .VI 
sec  later  this  water  supply  was  reduced  to  a  small  meter 
upward  Mow  to  give  final  4%  acetone  solution.  The  fiber 
was  then  passed  to  a  godet,  over  an  antistatic  coated  porce-j 
lain  roller  (Nekal  solution)  and  then  to  bobbins  at  <o  meters 
per  inin  (210  fpm  i  from  an  original  25  meters.  The  stretch- 
ing ratio  was  approximately  2'.-:l.  With  this  equipment 
'Ml  to  1,000  denier  yarns  could  Ix-  made,  although  KHi  to 
180  was  customary.  The  capacity  of  the  equipment  was  ap- 
proximately 1,300  11)  per  day. 

Staple  filler  was  produced  on  a  horizontal  machine  hy  a 
continuous  automatic  mechanized  process.  The  tow  was 
spun,  stretched  during  washing,  crimped,  cut,  dried,  and 
packed  in  3'1)  ll>  Kales.  For  spinning,  6  machines  of  13 
spinnerettes  had  .08  mm  (.003")  holes.  After  the  initial 
precipitation,  the  washing  was  conntercurrent  in  several 
stages  along  a  30  meter  (98  ft)  washer,  with  stretching 
lit-twrrii  each  stage  as  the  acetone  left  the  fiber.  Total 
*t  retch  was  300%.  The  final  speed  was  65  meters  per  min  or 
210  fpm.  The  lil>n  was  reduced  to  a  7  to  8%  acetone  con- 
tent and  was  3'j  denier,  strength  1.8  to  2.2  gm  per  denier,] 
elongation  4(1',  at  break. 

The  tow  was  crimped  by  two  rollers  continuously  jam- 
ming it  into  a  little  cavity  with  a  flap  which  released  under 
piesxure  when  overloaded.  The  crimped  tow  passed  to  the 
cutter,  which  consisted  of  two  gear-like  tangential  rolls. 
with  a  Hying  cutter  which  hy  synchronization  cut  into  each 
gear  opening,  thus  cutting  the  fiber  to  staple  lengths.  Belts 
then  delivered  the  cut  staple  to  a  30  meter  long  (W  ft), 
3  meter  wide  (''.X  ftp.  mesh -belt,  drying  oven,  which 
operated  at  45"»  !  (HfP)  at  the  feed  end  and  70°C  ( 158°F) 
at  the  exit,  with  belt  spacing  "4".  The  estimated  speed 
is  8  to  10  fpm.  This  staple  was  sold  to  spinners  throughout 
i  ierinanv  ami  then  woven  for  chemical  filter  cloths,  army 


JULY   1946 


tent    bottoms,    chemical    resistant    clothing,    and    chemical 
ropes.     Large-scale  production  started  in  1939. 

The  spinning  of  polyamides  was  an  important  phase  of 
the  textile  and  plastics  industry  in  Germany.  There  were 
three  main  types  of  polyamides  used.  The  first  was  called 
Perlon  L,  as  a  finished  fiber,  or  Igamid  B,  (omega  capro- 
lactan)  as  the  polymer.  The  second  was  Perlon  T,  which 
corresponds  to  6-6  type  polyamide.  The  third  had  Perlon 
U,  sometimes  known  as  Igamid  U,  as  the  base  resin,  and 
was  made  from  isocyanate  or  polyurethane.  Perlon  L, 
or  the  caprolactan  type,  was  spun  with  5  to  10%  residual 
monomer.  This  facilitated  stretching.  After  the  usual 
4  to  1  stretch,  the  residual  monomer  was  washed  out  with 
hot  water.  Strength  was  reported  as  5  to  6  gm  per  denier 
with  20%  elongation.  Four  percent  water  remained  in  the 
yarn.  This  rose  to  10  to  12%  on  24-hour  immersion.  The 
melting  point  was  220  to  240°C  (428  to  464°F). 

Two  methods  of  spinning  were  used.  The  conventional 
grid  method  accounted  for  slightly  more  than  one-half  of 
the  production.  The  second  method  used  a  melted  tape.  In 
grid  spinning,  coarse  flake  was  fed  through  a  hopper  to  a 
vertical  cylinder  through  which  nitrogen  was  fed  counter- 
currently  to  displace  air,  thence  to  the  melting  chamber, 
which  consisted  of  a  hollow  tubular  grid  and  jacket  through 
which  270°C  (518°F)  Dowtherm  circulated.  The  molten 
polymer  was  fed  through  streamlined  channels  to  a  stain- 
less steel  pressure  pump  in  series  with  a  metering  pump, 
thence  through  a  silica  filter  to  the  spinnerette.  This  was 
all  enclosed  in  a  heated  jacket.  The  melting  chamber  was 
about  7"  in  diameter,  and  the  assembly  length  from  spin- 
nerette to  box  top  was  about  6'  over-all.  Construction  was 
stainless  steel  with  the  plate  screened  under  the  sand  filter 
of  stainless  or  phosphorous  bronze.  The  standard  spinner- 
ette was  of  stainless  steel  lyi"  in  diameter,  3/16"  thick, 
ami  had  12  filament  holes  approximately  .010"  in  diameter. 
Filaments  were  collected  on  the  first  bobbin  prior  to  final 
stretching  a>~  160  denier,  12  filament  yarn  at  the  rate  of  750 
meters  per  min  (2400  fpm).  The  latter  stretching  reduced 
it  to  40  to  45  denier  and  was  done  cold. 

The  newer-type  band  spinning  was  simpler  and  more 
compact.  Metering  was  more  accurate,  and  pumps  with 
their  packing  gland  problems  were  eliminated;  also,  no 
nitrogen  was  required.  The  lower  cost  was  somewhat 
balanced  by  the  extra  operation  of  making  bands  of  rec- 
tangular cross  section  approximately  20  by  4  mm  (.8"  by 
.16"  i.  The  band  was  formed  by  hot  extrusion  and  was 
held  to  close  dimensions  by  a  groove  in  two  large  wheels, 
one  of  which  produced  tension  on  the  other;  and  by  a  few 
picture  rolls  forcing  the  material  into  the  groove.  The 

nd  was  then  reeled.  The  groove  wheels  or  rolls  were 
up  tn  8'  in  diameter  in  production  equipment. 

The  spinning  machine  height  from  the  feed  end  to  the 
spinnerette  end  was  about  18".  The  tape  was  fed  by  accu- 
rately driven  geared  rollers  into  a  heated,  rectangular  pas- 
•ge,  in  which  it  fitted  so  closely  that  it  acted  as  a  con 
Bnuous  feeding  piston.  Part  way  down  the  rectangular, 
Rated  passage-way,  the  tape  melted  and  was  forced  on  by 
the  tape  feeding  as  a  piston.  At  the  bottom  end  of  the 
[>a--.age  was  the  spinnerette  with  the  filter  as  described 
in  the  previous  method.  The  speed  was  600  meters  per 
minute  (approximately  2000  fpm)  on  the  first  bobbin.  This 
was  limited  by  the  rate  of  melting.  This  could  be  improved 
by  additional  engineering.  The  above  units  melted  at  the 
rate  of  40  gm  per  min  or  better  than  5  Ib  per  hr.  The 
stretching  system  was  the  same  as  described  previously. 
The  polyamide  fibers  as  produced  by  these  methods  were 
used  extensively  in  military  fabrics  and  ropes. 

In  one  plant  experimental  spinning  from  polyvinyl  chlo- 
ride of  very  high  molecular  weight  showed  good  results. 
Tile  spinning  process  was  not  unlike  conventional,  solution- 
spinning  into  a  non-solvent.  In  this  particular  case  the 


A  miscellany  of  polyamide  fiber,  tape,  sheet,  and  molded 
samples.  The  fiber  was  used  in  military  fabrics  and  ropes 


Among  the  earliest  injection  molded  parts  (Capt.  Nalle-SPI 
collection).  They  were  made  by  Bebrueder  Eckert, Nuremburg 


Jl  LY  1946 


PLASTICS 


65 


TO   PRODUCT  IN    PLASTICS 


OW  WE    CAN 

INJECT' 

up  to  18  OUNCES 


Here's  the  sure  cure  for  those  bother- 
some  situations  that  call  for  big  parts 
with  a  number  of  differing  wall  thick- 
ni  --.•-  .  .  .  \\  c  nou  have  -|»-i  ial 
equipment  lhat  will  handle  *injec- 
liun  molding  up  to  18  oz.,  under 
extreme  procure — creating  unusual 
sizes  and  >ha|x--. 

Rcmrmbrr.  (ix>,  u<-  laminate  and  fab- 
ricate as  well,  and  are  set  up  to  handle 
complete  ;i--einblit>.  \-k  on  your  let- 
terhead fur  our  HiK>klet  No.  3-A  show- 
ing  hundreds  of  our  special  creations. 


FELSENTHAL 
PLASTICS 

G.   FELSENTHAL   &    SONS 

41M  W.  GRAND  AVI.     CHICAGO   SI.  III. 

BRANCH  orriciS:  NIW  YORK  •  DITROIT 


;  high  molecular  weight  polyvinyl  chloride  was  spun  from  : 
16%  cyclohexanone  solution  at  60°C  (140°F)  into  J-ethy 
hexanol.  The  spinning  was  downward  through  a  larg< 
glass  tube.  At  the  bottom  of  the  tube,  the  direction  wa: 
changed  by  135°  and  the  spinning  was  then  upward.  Th< 
resulting  fiber  from  the  solution  was  steam-stretched  ion 
to  six  times  its  original  length  to  a  1  to  2  denier  filament 
It  was  stated  that  this  filament  had  the  unusually  higl 
strength  for  polyvinyl  chloride  of  4  to  5  gm  per  denier 
While  heat  resistance  wa-  limited,  it  was  stated  that  ihe-< 
fibers  had  good  abrasion  resistance  under  normal  wear  con 
ditions.  Experimental  fabrics  had  been  made,  and  experi 
mental  shoe  laces  of  this  fiber  showed  good  general  prop 
erties.  The  heat  resistance  was  somewhat  higher  than  tha 
of  normal  polyvinyl  chloride  because  of  the  extremely  higl 
molecular  weight  product  used. 

Protective  Coatings 

Before  the  war,  Germany  used  around  80,000  tons  o 
natural  oils,  while  during  the  war  only  15,000  to  20,00 
tons  were  available.  To  a  Dr.  Otto  Jordan  fell  the  task  o 
finding  suitable  substitutes  for  this  large  amount  of  mate 
rial  and  the  system  he  built  up  permitted  reduction  of  th 
oil  used  to  less  than  10,000  tons  per  year.  No  general  sub 
stitute  was  found,  but  for  specific  uses  the  German  indu-tr; 
built  up  cellulosics,  nitro-cellulose,  the  ureas,  plasticize 
phenolics,  polyvinyl  acetate  emulsions,  and  extensions  of  th 
alkyds,  which  had  already  achieved  importance  in  boi 
solution  and  emulsion.  In  the  course  of  this  work,  it  wa 
also  found  that  lead  cyanamide  was  a  preferred  pigmen 
for  extending  the  film  life  because,  unlike  red  lead  or  zin 
white  combinations,  which  saponify  the  oil  esters,  it  re 
mained  completely  inert  and  the  pH  of  the  film  was  no 
reduced  after  6l/2  years.  With  the  red  lead  and  zinc  whit 
combinations,  the  film  often  became  acid  within  a  couple  o 
years,  and  protection  against  corrosion  was  reduced. 

The  trend  in  the  various  chemical  types  may  be  summai 
ized  as  follows: 

In  the  phenolic  field,  Luphen  varnishes  were  condense 
in  butyl  alcohol.    The  reaction  involved  one  phenol,  on 
formaldehyde  in  the  presence  of  4  to  6  parts  butyl  alcoh< 
for  6  to  8  hr  at  120  to  140°C  (248  to  284°F).   Th. 
re-in  (Luphen)  was  cured  cold  with  catalyst  of  1  to  51 
HC1  just  before  application  or,  occasionally,  with  toluen 
sulfonic  acid.   It  was  effectively  plasticized  by  additions  o 
adipic  acid  and  trimethylolpropane  condensed  to  a  honey 
like  flow.   This  same  type  of  adipic  ester  resin  was  1 
used  for  both  phenolics  and  ureas. 

The  phenolic  resins  were  usually  reduced  to  50',  -oli< 
with  alcohol  for  spraying.  It  could  be  used  clear  or  pij 
mented  on  wood  or  metal.  Luphen  145.  not  carried  as  fij 
as  the  above  resin,  was  soluble  in  ethyl  alcohol  and  wi 
cured  by  baking  at  165°C  (329°F). 

Before  the  war,  wood  finishing  established  for  farm  ml 
chinery  was  done  without  alkyds  carrying  iron  oxide,  bt 
the  later  systems  involved  priming  the  wood  with  phenol 
or  urea  resin  uncured  followed  by  a  top  coat  of  pla-tici/.e 
Luphen  (phenolic)  or  Plaslofol  (soluble  butylated  n> 
maldehyde  resin).  Durophen  was  a  term  used  for  plajj 
cized  phenolics.  Important  varieties  were  287  U' .  *75.  .'0! 
and  308. 

In  the  alkyd  field,  the  railroads  used  a  55  to  OO'J  linsee 
or  dehydrated  castor  oil  drying  resin  or,  in  sonic  casl 
nitro-cellulose  non-curing  resin.  For  marine  work,  .-tlkydt 
I  from  linseed,  hexanetiol.  trnncthylolpi  op.me  and  phth.ili 
anhydride  gave  an  equivalent  of  55%  linseed,  acid  numlx 
less  than  10.  I  In-  resin  \\mild  carry  zinc  oxide. 

For  inside  finishing  the  Germans  finally  ended  with  alky 
plasticized  phenolic  and  tall  oil  which  had  the  equivalent  < 
(Continued  on  page  83) 


66 


PLASTICS 


JULY  194 


Let  your  HEAD  take  you 


(The  average  American  today 
has  a  choice  of  just  going  where 
"his  feet  take  him" ,  or  choosing 
wisely  the  course  to  follow.  Let's 
skip  ahead  JO  years,  and  take  a 
look  at  John  Jones — and  listen 
to  him  .  .  .  ) 

"QOMETIMES  I   feel  so  good  it 
*^  almost  scares  me. 

"This  house — I  wouldn't  swap 
a  shingle  off  its  roof  for  any  other 
house  on  earth.  This  little  valley, 
with  the  pond  down  in  the  hol- 
low at  the  back,  is  the  spot  I  like 
best  in  all  the  world. 

"And  they're  mine.  I  own  'em. 
Nobody  can  take  'em  away  from 
me. 

"I've  got  a  little  money  com- 
ing in,  regularly.  Not  much — but 
enough.  And  I  tell  you,  when  you 


can  go  to  bed  every  night  with 
nothing  on  your  mind  except  the 
fun  you're  going  to  have  tomor- 
row— that's  as  near  Heaven  as 
man  gets  on  this  earth! 

"It  wasn't  always  so. 

"Back  in  '46 — that  was  right 
after  the  war  and  sometimes  the 
going  wasn't  too  easy — I  needed 
cash.  Taxes  were  tough,  and  then 
Ellen  got  sick.  Like  almost  every- 
body else,  I  was  buying  Bonds 
through  the  Payroll  Plan — and  I 
figured  on  cashing  some  of  them 
in.  But  sick  as  she  was,  it  was 
Ellen  who  talked  me  out  of  it. 

"  'Don't  do  it,  John!'  she  said. 
'Please  don't!  For  the  first  time 
in  our  lives,  we're  really  saving 
money.  It's  wonderful  to  know 
that  every  single  payday  we  have 
more  money  put  aside!  John,  if 


we  can  only  keep  up  this  saving, 
think  what  it  can  mean!  Maybe 
someday  you  won't  have  to  work. 
Maybe  we  can  own  a  home.  And 
oh,  how  good  it  would  feel  to 
know  that  we  need  never  worry 
about  money  when  we're  old!' 

"Well,  even  after  she  got  better, 
I  stayed  away  from  the  weekly 
poker  game — quit  dropping  a  little 
cash  at  the  hot  spots  now  and 
then — gave  up  some  of  the  things 
a  man  feels  he  has  a  right  to.  We 
didn't  have  as  much  fun  for  a 
while  but  we  paid  our  taxes  and 
the  doctor  and — we  didn't  touch 
the  Bonds. 

"What's  more,  we  kept  right 
on  putting  our  extra  cash  into 
U.  S.  Savings  Bonds.  And  the 
pay-off  is  making  the  world  a 
pretty  swell  place  today!" 


The  Treasury  Department  acknowledges  with  appre- 
ciation the  publication  of  this  advertisement  by 


ZIFF-DAVIS    PUBLISHING    COMPANY 


JULY  1946 


fLASTICS 


67 


ZEIN 


CELLULOSE 
ACETATE 


HARD  RUBBER 


LOW   DENSITY   BALSA 


GLASS 


POLYSTYRENE 


Seven  month*  outdoor  exposure  showed  no  or  very  little  effect  on  glass,  and  varying  effects  on  other  materials 

Properties  of  Core  Materials 

Kjeniamin    ff/.^rxifroaanttC^i/elyn 


U.  S.   Department  of  Commerce.   National   Bureau  of  Standards 


IN  A  report*  prepared  by  the  authors  and  summarized 
herein,  experiments  xvcrc  discussed  which  add  to  the 
general  More  of  knowledge  being  accumulated  on  the  prob- 
lem of  selecting  the  best  core  material  for  laminated  sand- 
wich structures  for  aircraft  and  other  applications.  The 
materials  covered  in  the  survey  included  a  cellular  hard 
rubber,  a  cellular  glass,  bal-a  wood,  and  lour  expanded 
plastic-— cellulose  arnate.  |x,lvstyrene.  a  urea- formalde- 
hyde, and  a  rein  f  protein  i  l>asr  product. 

The  pnr|Mis<-  of  the  investiKation  was  to  learn  the  physical 
and  mechanical  properties  of  some  expanded  plastics  and 
other  low-density  materials  available  from  commercial 
sources  as  an  aid  in  the  selection  of  materials  for  specific 
applications.  The  properties  determined  were  density: 
thermal  conductivity;  dimensional  stability:  resistance  to 
water,  lubricating  oil.  gasoline,  and  other  chemicals;  flex- 


.,_...,..,  I'lailirt  »n<)  Other   Icm  l»en«it.    Mate 
iilrnH  and  Evelyn  Koenig  of  the  National  Bureau 

—    ..___...-     ..-..„_.    Arl»...T.    I  .rnimiitee    for    Aeronautic*,    Terhniral 
Mel*  No.  *»l.  September.   I»«S 


--OHM.  Kipa 

rUU."  br  Brt,,.™..n  \(    A.,1  — 
e<    Suodar.il.    National    A<t>i 


Study  contributes  to  data  on 
low-density  cores  and  their 
suitability  /or  various  uses 


ural  atxl  compressive  strengths;  and  moduli  of  elasticity 
I  In  rrllulosi-  acetate  expanded  plastics  was  furnished  if 
sheets  d.5"  thick  with  cylindrical  cells  oriented  perpendicu' 
larly  to  the  plane  of  the  sheet.  This  material  was  forniM 
by  mixing  cellulose  acrtate  with  a  solvent,  putting  the  miv 
ture  under  variable  tenifieratiires  and  pressures  and  thel 
suddenly  releasing  the  pressure.  The  expanded  |>olystyren< 
npplied  under  the  ilesignation  Q-103 Styrofoom  in  one 
inch  sheets,  with  closed,  approximately  spherical  cells 
4«"  in  diameter. 

The    protein  base    ••ponge.    made    from    rein    with 


I*I..\XTH 


JULY  194« 


plasticizer,  was  supplied  in  1.4"  sheets.  This  material, 
known  as  "hard  Amak  sponge,"  had  closed,  spherical  cells 
of  approximately  Miz"  in  diameter.  The  faces  had  a  thin 
skin  of  the  same  composition  as  the  core.  The  expanded 
urea-formaldehyde,  Resin  Foam,  was  made  as  slabs  about 
2"  thick,  with  approximately  spherical  interconnecting  cells. 
According  to  the  manufacturer,  the  resin  is  treated  with 
a  frothing  material,  poured  into  the  desired  shape,  and  given 
permanent  form  hy  the  addition  of  a  setting  agent. 

The  expanded  hard  rubber  was  made  in  slabs  one  inch 
thick  and  designated  as  "No.  2266  hard  cellular  board."  It 
contained  35%  filler  and  10%  softener,  and  had  a  skin  of 
the  same  composition  as  the  core.  The  material  had  closed, 
approximately  spherical  cells  about  %t>"  in  diameter  with  a 
few  larger  cells  about  Vie"  to  }/&"  in  diameter.  Balsa  in  two 
densities  was  supplied  as  boards  2"  to  4"  thick.  Glass,  as  a 
closed,  spherical  cell  product,  called  Foamglass,  was  fur- 
nished in  2"  slabs.  The  Foamglass  had  been  "cellulated  by 
the  evolution  of  internal  gas  at  high  temperatures." 

The  thickness  of  the  test  specimens  was  the  same  as  that 
of  the  sheets  supplied,  except  for  the  balsa,  in  which  case 
the  specimens  were  taken  from  1"  thick  planed  boards.  The 
lengthwise  direction  was  taken  along  the  length  of  the  sheet 
and  for  the  balsa  was  parallel  to  the  grain.  If  the  sheet  was 
square,  the  lengthwise  direction  was  arbitrarily  chosen. 

The  tests  showed  that  each  material  tested  had  its  ad- 
vantages and  disadvantages.  The  survey  made  no  attempt 
to  give  the  materials  an  overall  rating.  It  would  appear 
that  the  choice  of  a  core  will  depend  on  the  demands  of  the 
particular  application. 

The  densities  of  the  materials  tested,  in  gm/cc,  were 
polystyrene  0.02,  urea  formaldehyde  0.04,  hard  rubber  0.07 
to  0.08,  low-density  balsa  0.07  to  0.09,  and  cellulose  acetate 
0.08  to  0.09.  The  Foamglass  and  zein  product  had  densities 


.02      .04      .06      .08      .10       ./Z       ./-»       .16       .18        20     ,zz      ,Z4      .2JS 
COMPRESS/YE     STBAIM   f/x/m.j 


Flatwise  compressive  stress-strain  curves 


of  about  0.17  and  the  high-density  balsa  0.16  to  0.32  gm. 
Since  the  densities  and  cellular  structure  of  an  expanded 
plastics  may  be  varied  to  some  extent,  the  materials  cannot 
be  rated  on  density. 

On  thermal  conductivity,  expanded  rubber  rated  best  with 


UNDERWOOD-SUNDSTRAND  ADDING 
MACHINE  PARTS  MOLDED  BY  AUBURN 


AUBURN'S 

Plastics  Gallery 

Auburn  molded  plastics  have  served  American 
industry  for  the  last  70  years.  Auburn  "know- 
how"  is  the  product  of  that  experience  ...  it  is  the 
extra  value  you  get  when  you  choose  Auburn  as 
your  custom  molder. 


AUBURN  BUTTON  WORKS,  INC 

rouNOID  IN    l«r»  •  AU«U«N,  NtW  TOIK 


JULY  1946 


AUBURN   ENGINEERED  PLASTIC   PRODUCTS 

Comprettion,  Transfer,  and  Injection  Molding 

Automatic  Rotary  Molding  (or  Matt  Production 
Extruded  Vinyl  or  Acetate  Tubes  and  Shape* 
Cellulose  Nitrate  Rods,  Sheets,  Molded  Parts 
Mold  Engineering  and  Complete  Mold  Shop 


PLASTICS 


Edgewise  Compression  Data  for  Low-Density  Materials 


c 

Nractio.             Do**,. 
of                   Average 
•Odta,                  (•/0.1 

No.  0- 

MoatjeM  of  BaeMckV 

Compreurve 
YMd  Strew 

Spherical 
Heod 
U«ed 

Rate  of 
Head 
Motion 
(in./.ln.) 

Specimen 
Height 
(in.) 

Average 

lib    in". 

lib/in" 

A.^'  jg- 
ft      -: 

Rang. 

(Ib/inl 

.;-.,.                           -« 
•OW..M  0.079.. 

«g*Wi»e  0.019.. 
tmwnx  0.019.. 
««ttiw«e  0.016.. 
•H.S.IM  0.081.. 
•Mi.lM  0.079.. 
•gthw.M  0.077'.. 

3.. 

....3.. 

.'.'.'.'3!! 
....2.. 
....2.. 
....3.. 
....3.. 

350... 
350... 
740... 
820... 
790... 
3.600... 
4.200... 
95.000... 

25O-50O.  . 

10  to  20'  

..No..  . 

...0.1  

1 

c 

..01 

.    .1 

.16-17  

..No  

...0.2  

2 

c 

730-950  
660-920... 
3.400-3.900.. 
3.900-4.500... 
.  ..68.0OO-I  38,000 

16... 
35... 
52.. 
50... 
760... 
670... 
60'.. 
40'.. 
i  inn 

14-18  
32-37  
51-54  
46-52  
5OO-9SO 

... 

..No.... 
..YM... 
..No  
..No.... 
.  .Ye«  

.".'."'. 

...0.2  
...O.I  
...0.2  
...0.2  
...0.05  

2 
3 
2 
2 
2 

Hard  robber  li 

C 

C 

..No  .  . 

..005      .. 

2 

otewne  0.089.. 
0.073.. 

....3.. 
....3.. 
2 

4.500... 
3.000... 

3,500-5700.. 
.....2,400-3,500.. 

48-75  
37-46  

... 

..YM  
..No.... 

.No 



...0.05  
...0.05  
...005.... 

2 
2 
2 

C 

0  32 

4 

750000' 

.  .690,000-810.000  4700.  .  . 

.  .  .  1  2.00O-32.OOO  2OO".  . 
.  .  .  1  4,000-27,000  1  80'.  . 

...4,400-4,900  
150-300  

Two  wM< 
•Two  without 

Ye.  

}..., 

).00  3-0.008. 

2 

•oeewtee  0.21'... 
0.1  8«... 

....3.. 
3.. 

20.0OO... 
20.000... 

...0.05  

2 

140-250  

..No  

...0.05  

2 

"•  g  ~ 

rically  umilar  with  height 
The  dope  of  the  .freight 
tenee.     'lonj.  0.067  to 

and  width  each  equal  to  twice  the  thjckneu.     fated  on  eompreiuv.  deformation  o.  Indicated  by  change  in  distance  between  top 
portion  of  the  graph  wa.  uied  to  obtain  the  modului.     'Streii-.troin  diagram  doe.  not  become  quite  horizontal,  *o  the*e  value,  are 
0.089.     'Rang.  0.17  to  0.27.     'Range  0.16  to  0.22.     TDiol  gage,  graduated  to  0.0001  inch  uted  for  Indicating  distance  between 

•at  yWd  Mreei  tn  MM  Meal 
beortng  block,  in  Mb  to*. 

K  being  0.25  Btu  per  hr  per  sq  ft  per  "F  per  in.  at  95°  F. 
This  figure  compares  favorably  with  the  insulating  value 
of  the  rigid  and  most  of  the  fibrous  commercial  insulating 
materials.  Low-density  balsa  rated  next,  polystyrene  ran 
a  close  third,  and  cellulose  acetate  came  fourth. 

On  resistance  to  extreme  temperatures  and  high  humidi- 
ties, polystyrene  again  showed  the  best  values,  weight 
changes  amounting  to  less  than  \l/i%.  Glass  exhibited  very 
slight  changes  in  weight.  The  hard  rubber,  zein,  and  low- 
density  balsa  changed  in  weight  from  5%  to  20%  when  sub- 
jected alternately  to  high  and  low  relative  humidities. 

The  least  dimensional  changes  occurred  in  the  inorganic 
product,  glass,  and  in  the  polystyrene.  The  changes  were 
generally  less  than  0.5%.  The  negative  trend  of  the  changes 
in  glass  may.be  explained  by  the  crumbling  caused  at  the 
surface  of  contact  by  handling.  The  other  materials  all 
changed  from  1%  to  5%  when  exposed  alternately  to  high 
and  low  relative  humidities. 

Some  of  the  samples  fared  much  better  than  others  on 


the  natural  weathering  test.  The  inorganic  glass  foam 
exhibited  the  least  shrinkage  and  warp  and  appeared  unaf- 
fected by  the  exposure.  The  polystyrene  likewise  shrank  or 
warped  very  little,  but  the  face  exposed  to  the  light  became 
brittle  with  the  result  that  erosion  by  the  wind  reduced  the 
sample  to  half  its  original  thickness.  Specimens  subjected 
to  an  ultra-violet  light-fog  accelerated  weathering  test  (de- 
scribed in  Method  6021  of  Federal  Specification  L-P-406a) 
turned  yellow  and  the  surface  became  sufficiently  brittle  that 
it  could  be  eroded  by  a  stream  of  air  blown  over  the  surface. 
This  behavior  was  similar  to  that  observed  on  the  specimen 
exposed  outdoors  for  seven  months. 

The  greatest  dimensional  change  of  the  hard  rubber  in 
either  direction  was  less  than  that  of  the  balsa  in  the  cross- 
grain  direction,  in  which  the  greatest  change  occurred. 
The  hard  rubber,  however,  developed  a  greater  warp  than 
the  balsa.  The  changes  in  the  dimensions  of  the  cellulose 
acetate  and  zein  were  10%  or  more,  and  these  materials 
warped  badly. 


Changes  in  Weight  and  Dimensions  of  Low-Density  Materials  in  Accelerated  Service 

Tests  Involving  Extremes  of  Temperature  and  Humidity' 
T«.t  I  Te.t  II  T  ,,t  III  Tml  IV  T«t  V 


Change 

Change 

Change 

Chang. 

Chang. 

Change 

Change 

Chang. 

Change 

Change 

Change 

after 

after 

after 

after 

after 

after 

after 

after 

after 

after 

after 

24   hour. 

24   hour. 

72   hour. 

24   hour. 

24    hour. 

24  hom 

24  noun 

24   hom 

24   hour. 

24   houn 

24     hour. 

at   I40*f 

ot   140  f 

at  140"? 

ot  1  60°f 

ot  160°F 

ot  I75">F 

at  175«f 

at  175°f 

ot-40-f 

at  175*f 

al-40«F 

Mote»ol 

88%«.M. 

In  oven 

in  oven 

70-75% 

In  oven 

100%«.H. 

in  oven 

70-75% 

m 

in  oven 

(%) 

l%l 

(%l 

(%) 

R.H. 

(%) 

(%) 

(%) 

R.H. 

{%) 

m 

l%1 

.  -0.2 

0.0 

-0.4 

,  -0.2 

,  -2.7 

.  -0.2 

.  -2.0 


.+3.4.. 
-1.0.. 

•  it.. 
.  +1.6.. 
.  •  52.. 
.  -6.2.. 


Weight 

...  -3.6 

...+0.3.... 

...  -5.3 

...  -2.1 

...  -5.2 

...  -6.7.... 


,  -0.4 -0.8... . 


.  +  6.9... 
-  0.5... 
.+11.4... 
.+  6.8... 
.+19.8... 
.+144... 
.  +  2.6... 


..  -  6.8.. 

..+  0.2. . 

..  -11.2. . 
...  -  7.4.. 
...  -19.8.. 
...+IS.O. 
...  -  4.4.. 


....+  14.. 
...  -  1.2. . 
...+  5.0. . 
,...+  0.2. . 
....+10.4... 
....+  3.9. 
....  -  OJ. 


....+O.J. 
....  +0.3. 
....  -0.2. 
....+0.4. 
....+0.2. 
....+0.2. 
....+0.4. 


0.0 

7.2 

3.4.... 
11.0     .. 

84 

1.0 


. .     •  J.S 

...  -0.7 
...  -0.5 
...  •  1 .7 
...+1.M 

...+0.3 

...  -1.4 


+   1.2... 

0.0... 

-  0.2... 

-  O.I... 
+  2.4... 

-  0.3... 
4-    0.4... 

0.0... 


-  1.2. 
...+  O.I. 
...  -  04. 

-  3.1. 
. . .  -  0.8. 
...  -  0.3. 
. ..  -   1.0. 
...  *-   O.I. 


. . . .  -0.1 . 
....  0.0. 

-0.2. 

-0.2. 

....  -0.3. 
....  fO.3. 
....  »0.3. 
....  +0.1. 


length  and  Width1 

....+I.J -1.2 +   1.0 

+0.1 +0.2., 

»0.6 -14. 

....    -2.1 -2.6 

fO.4 -1.4. 


0.0 

+0.3 

....      0.0 


-0.3. . 
-0.8. . 


0.0. . 
..  0.4. . 
...+  0.6. . 
..+  0.3. . 
..+  0.0. . 
..+  1.4. 


0.0 +  0.2. . 


-  1.9... 
0.2... 
1.0... 
5.1... 
1.2... 
0.3... 

•  1.3... 
0.0... 


...+  0.2. 
...  -  0.2. . 
...+  1.2. . 
...  -  0.1 .. 
...+  2.0. . 

0.0. . 

0.0. . 
-  0.3. . 


+0.3. 

....     0.0. 

-0.6. , 

....+04. 
....  -0.2. 

-OJ. 

0.0. 

.     0.0. 


1.4  

0 

0.1  

-o 

14  

3.4 

3J  

•  0.8 

0.3'.'.'.'.'.'.'. 

,i  2 

1.0  

.  n  J 

0.2  

.  n.i 

Thkknou' 


r«»tirrr.«e 

00 

-05 

.      .       +  0. 

1             -05 

—  1  .•  
00 

t-  g.v  .  . 
00 

....  —   1  .«  . 
00 

u.u  
f  05 

+«.»  — 
+05              — 

OS  

00 

Mi 

•     1  8 

+  03 

•  03 

•  0  4 

—0  4 

2  2 

•     1  0 

—    1  0 

_/2.6               — 

22 

"   7 

1  3 

—  3.0 

—  5  0 

—0.7              — 

.  ,->  9 

Nerd  rwkfeer 

+    30... 

—   1  0 

..  -05 

t  1  0 

—  2.5 

•    0  5 

.    —   25 

+  3.0 

+OJ           .  — 

3.5... 

n  5 

>  | 

_    14 

. 

00 

—  14 

+    1  O 

1  0 

—  08 

00             — 

14 

0  0 

04... 

..       -  OJ  

•    0.2 

0.0. 

0.0. 

0.0  

0.0.  . 

0.0. 

-  0.5  

0.0  

0.0  

:1  2 

•01 1.  re 


otian  If  406o   Two  .p«.~. 


•  02.  f.i...l» 


aVMwniN  ir*r*«w«.  iwo  «y •*;.*»•*»  of  *oth  wtot»rial  w»r*  t*»t*>d  Th*  torn*  ,p*>-i«w»nt  w*r*>  «vbj»<1 
fr*»»  MM  p»ni<»i  eo**J«l-o«v  cokvlo»»d  to  p»rc»«tog»>  of  tfc*  Mtfal  weifM  or  dlm^ntiont  of  Mi*  eond 
•-  orw  In  *»•  »^-*t  t*  •»  *M  •rtfJor  o<  ,05 


.'•d  to  T*fH   1    to  V   com*CvH«*lv-  Th*  votwot  in  th« 
idMOA*d  tp#c»m»ft,  'frobobU  •ftor  in  *h*  valv*>i  it  of 


70 


.11  l.Y    1916 


Hard  rubber  ready  for  ilexural  test.    Right,  polystyrene  specimen  placed  for  flatwise  compression   test 


Glass  changed  weight  least  on  immersion  in  chemicals. 
As  the  report  notes,  however,  the  densities  need  to  be  con- 
sidered in  a  comparison  of  percentage  changes  in  weight. 
For  example,  glass,  hard  rubber,  and  polystyrene,  on  absorb- 
ing equal  weights  of  the  same  chemical,  would  have  per- 
centage increases  in  weight  of  1 :2 :8  as  the  densities  vary 
8:2:1.  Hard  rubber  and  low  density  balsa  are  of  about 


equal  density  and  are  readily  compared.  The  hard  rubber 
absorbed  much  less  chemical  in  all  instances  than  the  balsa. 
The  hard  rubber  exhibited  dimensional  changes  of  less 
than  1%  in  all  chemicals  except  the  gasoline  blend,  for 
which  changes  of  1%  to  2%  were  noted.  It  compared 
favorably  with  glass  in  this  respect.  The  low-density  balsa 
in  the  direction  of  the  grain  showed  dimensional  changes  of 


Expressly  designed  for 
granulating  the  various 
types  of  plastic  materials 

Advanced  design  features  enable 
Cumberland  machines  to  perform  at 
maximum  efficiency  the  special  cut- 
ting required  by  plastics  materials. 
Machines  are  made  in  two  styles: 
smaller  machines.  No.  0,  No.  Vt  and 
No.  IVi  as  at  right  (No.  Vt  illus- 
trated). Style  of  large  machines  as  at 
left  with  retractable 
knife  block  for  maxi- 
mum accessibility  (18" 
Machine  illustrated). 

Reguesf  illustrated 
CATALOG  NO.  200 

CUMBERLAND  ENGINEERING  CO 

Dept.  B — Box  216,  Providence,   R.  I. 


JULY  1946 


PLASTICS 


71 


Specialties 


Cold-  forged 

quickly  and 
economically 


The  special  rivet,  nail 

or  threaded  part  you  need  may  be  cold-headed — 
and  with  substantial  economy.  V/ith  these  advan- 
tages we  also  offer  you  the  added  strength  inher- 
ent in  cold-headed  parts. 

Chances  are,  too,  that  the  metal  you  require  is  an 
everyday  material  with  us.  A  wide  selection  of 
sizes  and  metals,  plus  almost  a  century  of  expe- 
rience in  working  them,  is  at  your  service. 

Tell  us  about  your  problem.  Send  sketch  or  sam- 
ple of  the  part  you  need.  No  obligation.  Ask  for 
free  catalog. 

JOHN  HASSALL,  INC. 

160  CLAY  STREET 
BROOKLYN   22.   N.  Y. 

Special  nails,  rivets,  screws 

and  threaded  parts 


less  than  1%  for  all  chemicals,  but  perpendicular  to  the  I 
grain  changes  of  2%  to  3%  were  obtained  for  several  of  I 
the  chemicals,  including  the  alcohols. 

The  cellulose  acetate  dissolved  in  acetone  and  diacetone  I 
alcohol  and  showed  changes  of  about  5%  in  length  and  I 
width  on  immersion  in  ethyl  alcohol  and  ethylene  glycoLI 
The  polystyrene  was  dissolved  by  acetone  and  the  gasoline  I 
blend,  shrank  about  45%  on  immersion  in  heptane,  and! 
swelled  about  22%  in  diacetone  alcohol.  The  remaining  I 
five  chemicals  used  in  the  test  caused  dimensional  change*  I 
up  to  1.5%.  The  dimensions  of  the  zein  were  principally  I 
affected  by  the  alcohols  and  acetone,  and  the  changes  in| 
dimensions  caused  by  other  chemicals  were  a  few  per., 'in 
The  expanded  urea-formaldehyde  exhibited  dimensional 
changes  of  less  than  1%  for  motor  oil,  heptane,  and  glyceroi, 
and  less  than  5%  for  the  other  chemicals  used. 

Xt-in  was  softened  by  water,  ethyl  alcohol,  ethylene  glycol, 
and  diacetone  alcohol.  The  expanded  hard  rubber  was 
softened  by  the  gasoline  blend.  The  slight  changes  in  son 
ness  index  obtained  in  other  instances  were  not  considered 
significant. 

The  flexural  tests  gave  some  interesting  results.  None 
of  the  other  materials  had  a  flexural  modulus  of  elasticity 
comparable  to  that  of  the  balsa.  The  highest  value  for  a 
synthetic  material  was  about  5,000  psi  for  hard  rubber 
compared  to  195,000  psi  for  balsa  of  slightly  higher  density. 
Unsatisfactory  load-deflection  graphs  were  obtained  with 
the  glass,  so  that  its  flexural  modulus  of  elasticity  was  not 
obtained.  The  glass  underwent  intermittent  crumbling  at 
the  pressure  and  support  pieces  and,  since  the  deflection  \va» 
measured  relative  to  the  supports,  the  resulting  load-deflec- 
tion graphs  were  highly  irregular. 

The  strength  of  the  balsa  was  much  greater  than  that  of 
the  other  products.  The  modulus  of  rupture  values  for  the 
strongest  materials  were  as  follows:  high  and  low-density 


300 
250 

200 
-N 
5  150 

Q 

Cj    100 

v| 

50 

0 

7/a 

>vf  Rubber 

^ 

^ 

^ 

> 

/ 

/ 

J 

/ 

-H 

0.05  in. 

— 

I 

DC 

FOKMA 

TION 

ISO 


Typical  flatwis»<ompr*uion  load  deformation  curve*. 
Sp*cim*ni  iu«d  In  lh»  (Ml  m*aiut»d  3"   X  3"  X   1" 


72 


l't..\STU'S 


II  I. V    1«»16 


balsa,  5,000  psi  and  800  psi  respectively;  glass  100  psi;  and 
hard  rubber,  90  psi. 

When  the  materials  were  compared  on  the  basis  of 
specific  strength  values,  however,  the  polystyrene  was  com- 
parable to  the  balsa  in  stiffness  and  in  specific  modulus 
of  rupture.  The  hard  rubber  was  the  second  best  synthetic 
material  with  a  tenth  of  the  stiffness  and  a  tenth  of  the 
specific  modulus  of  rupture  of  balsa  with  the  same  density. 
The  flexural  test  data  for  balsa  compared  reasonably  well 
with  values  reported  by  the  Forest  Products  Laboratory 
(Wiepking,  C.  A.  and  D.  V.  Doyle,  "Strength  and  Related 
Properties  of  Balsa  and  Quipo  Woods,"  U.  S.  Department 
of  Agriculture  Forest  Products  Laboratory  Report  No. 
1511,  June,  1944).  For  tests  with  and  without  pads  at  the 
support  pieces,  it  was  concluded  that  the  local  deformation 
due  to  concentrated  loads  did  not  affect  the  flexural  modulus 
of  elasticity  data  appreciably  for  the  polystyrene  and  hard 
rubber.  For  the  low-density  balsa,  however,  tests  without 
pads  resulted  in  flexural  modulus  of  elasticity  values  less 
than  half  of  the  corresponding  values  obtained  with  pads. 

As  in  flexure,  balsa  proved  much  superior  to  the  other 
materials  in  compressive  properties.  The  cellulose  acetate 
with  the  fibers  or  cylindrical  cells  oriented  perpendicularly 
to  the  plane  of  the  sheet  had  the  highest  flatwise  com- 
pressive modulus  of  elasticity  of  the  synthetic  organic  mate- 
rials, 3,400  psi.  The  average  value  for  balsa  of  slightly 
lower  density  was  about  1,500  psi. 

The  flatwise  compressibility  of  balsa  was  apparently  very 
sensitive  to  the  density ;  when  the  density  was  increased  two 
to  three  times,  the  effective  modulus  of  elasticity  values 
were  multiplied  ten-fold  or  more. 

The  polystyrene,  zein,  and  hard  rubber  were  about  equal 
in  flatwise  moduli  of  elasticity,  being  300  psi  to  600  psi. 
Again,  the  tendency  of  the  glass  foam  to  crumble  at  the 
bearing  surfaces  made  the  data  for  it  uncertain. 

The  hard  rubber  had  the  highest  effective  modulus  of 
elasticity  of  the  expanded  organic  materials  in  the  edgewise 
tests — about  4,000  psi  as  compared  to  100,000  psi  lengthwise 
and  3,500  psi  crosswise  for  balsa  of  the  same  density.  The 
compressive  moduli  of  elasticity  for  the  hard  rubber  in  the 
edgewise  tests  were  much  higher  than  those  in  the  flat- 
wise tests,  the  skin  on  the  material  probably  being  re- 
sponsible for  most  of  the  increase.  The  polystyrene  and 
zein  exhibited  compressive  moduli  of  about  800  psi  in  the 
edgewise  tests.  The  ratio  of  the  modulus  of  elasticity  to 
density  for  polystyrene  was  about  a  fortieth  of  the  corre- 
sponding ratio  for  the  low-density  balsa  in  the  lengthwise 
direction  and  about  equal  to  the  corresponding  ratio  in  the 
crosswise  direction. 

The  compressive  yield  stress  of  the  low-density  balsa  for 
the  lengthwise  direction  was  700  psi  compared  to  50  psi  for 
hard  rubber  and  16  psi  for  polystyrene. 

To  summarize,  hard  rubber  had  the  lowest  thermal  con- 
ductivity of  the  materials  tested;  glass  and  polystyrene 
changed  least  in  weight  and  dimensions  when  subjected  to 
extremes  of  temperature  and  humidity;  all  the  organic  prod- 


Water  Absorption  of  Low-Density  Materials1 

(Percentage  change  after  24-hr,  immersion  at  77°F) 
Material2 


Weight          length  &  Width3 


Thickness1 


Cellulose  acetate  
Polystyrene  
Zein  

201  
....78  - 
163 

2.9 

-0.2 

1  S 



.      0.7 
.-0.3 
4  0 

Urea-formaldehyde  .  . 
Hard  rubber  
Balsa,  low  density.  .  .  . 

399  
27.1  
....203  

139  

4.6 
0.1 
1.0 
3.5 
-0  1 

(length)... 
(width) 

.     4.4 
.      0.4 
,      2.7 

0  1 

«o 


We're  operating  over  capacity 
right  now — have  been  for 
months — yet  when  a 
manufacturer  comes  to  us  for  an 
especially  good  job  in  plastics 
molding— we  haven't  the 
heart  to  say  "NO"! 

We  do  have  a  definite  pride 
in  our  craftsmanship 
— which  makes  a  challenge  of 
every  job  that  comes  our 
way  no  matter  how  busy  we  are. 
That  is  undoubtedly  the  reason 
so  many  manufacturers  call 
upon  us  in  the  first  place. 

So  send  along  your  sample 
product  or  blueprint  and  we'll 
give  you  the  benefit  of  honest, 
experienced  advice  at  least, 
and,  if  possible,  the  satisfaction  of 
a  Continental  "turned-out"  job. 


CONTINENTAL 

PLASTICS  CORPORATION 


308   WEST   ERIE   STREET 
CHICAGO    10,   III. 


'Procedure  same  as  that  of  Method  7031,  Federal  Specification  L-P-406o.  'One 
specimen  of  each  material  was  tested.  The  percentage  change  is  based  on  the  Initial 
weight  or  dimensions  of  the  conditioned  specimens.  'Probable  error  in  the  values  Is  of 
the  order  of  ±0.2.  'Probable  error  in  the  values  is  of  the  order  of  ±0.5. 


JULY  1946 


PLASTICS 


73 


Changes  in  Weight  and  Dimensions  of  Low-Density  Materials  Immersed 
for  7  Days  in  Chemicals  at  25°  C1 


Chemicoh 

Cde» 

lose 
Acetate 

Poly- 
styrene 

Ut 

Urea- 
formal- 
dehyde 

Hard 
Rubber 

Low- 
Density 
•aba 

Glass 

Water  
Ethyl  okohol.  95'  

.  ..420.    .. 
...300.    .    . 
...250.    ... 
...240.    ... 
Dissolved 

130.    
210  
100  
180  
300  
Dissolved  

Weight 
1  50  
280  
310  
40  
480  
200  
160  
130  
150  

Length  and  W 

-0.8  
1  0.0  

..    960.    . 
..1440.    . 
..    560.    . 
..    200.    . 
.1570 

65.    .. 
52.    .. 
40.    .. 
3h   .. 
.    79    .. 

510  
590  
250  
210  
320  

10. 
7. 
17. 
16. 
16. 

Glycerol  
Dtocetone  alcohol 

..Dissolved. 

..1170.    . 
.  .  1  760.    . 

100.    .. 
55. 

820  
1  90  

5. 
14. 

Motor  oil  (SAE  «IO)  
Gasoline  blend-'  
Heptane  

Woler  
Ethyl  alcohol.  95'  ,  

...160. 
...150.    .    . 
...170.    .    . 

...      2.4... 
...      5.8.. 

180  
Dissolved... 
64  

-0.7  
0.7  

1370 

210 

490  

6 

..1260.    . 

idth* 

...      2.0. 
...      1  .9  . 

46.    .  . 

0.0.  . 
0.6.  . 

320  

L            W 
0.7.  .      2.6. 
0.8.  .      1.8. 

9. 

-0.7 
0.0 

Ethyleno  glycol  
Glycerol  

...      6.2... 
.  .  .  —02.  .  . 

1.4  
.    .    .     0.0  

5.4  
..  .    .—08.  .        .    . 

...-1.2. 
..  —  0.8. 

0.0.  . 
.     01.. 

0.8.  .      2.6. 
0.7.  .     0.7. 

-0.1 
0.0 

Dissolved. 

23.6  
Dissolved..  .  . 

11.3  
—0.4  

...-1.8. 
...—  1.2. 

-0.2.  . 
0.0.  . 

0.4.  .      2.0. 
0.0.  .      1.4. 

-0.1 
0.8 

.  Dissolved  .  . 

Motor  oil  (SAE  -10)  
Gasolineb  lend1  

...-0.1... 
...     0.2... 
...-0.7... 

-1.0  
Observed.... 
-49.3  

-0.4  
-0.2  
-0.3  

.  .  .      0.1  . 
...      3.0. 
...-0.8. 

-0.5.  . 
2.1.. 
0.6.  . 

-0.2..-0.1. 
0.0.  .     0.1. 
-0.3..-0.3. 

-0.1 
-0.2 

Water  

-1.0.  .  . 

-1.1  

Thickness4 
.      1.0  

.      2.6  

-0.8  

1  .4  

-0.7 

Ethyl  okohol.  95   ,  . 

0.4... 
—0.7.  .  . 

0.6  
-0.4  

.     8.3  
.      6.0  

.      1.7  
.  —  1  .4  

0.6  
-0.4  

3.2  
2.0  

0.1 
0.1 

—  1  4 

1  2 

1  6 

09 

06 

2  4 

00 

Diocetone  alcohol.  .  . 

Dissolved 

20.0  
Dissolved  

.    13.9  
.-0.7  

.-1.5  
.  —1.6  

-0.2  
0.0  

0.9  
1.3  

-0.1 
05 

Dissolved  . 

Motor  oil  (SAE  -101. 

-05.  .. 

—0  2  

.  —2  1 

02  

00  

0.0  

01 

Gasoline  blend1  

1  3. 

Dissolved 

27 

4  3 

1  2 

00 

—  03 

Heotone 

-0.7... 

-41  7  

.  —06  

.      03  

—  04  

—19  

-0.7 

'On*  splcUlu  of  eoch  leoteriol  was  tested.  Tt 

e  percentage  change  Is  based  on  the  initial  weight  or  dimensions  of  the  conditioned  specimen. 
1  5  per  cent  xylene.  and  5  per  cent  benzene.     frobable  error  in  the  values  is  of  the  order  of 

The  gasoline  blend  consisted  of  60  per 
t  0.2     'Probable  error  in  the  values  of 

the  order  of   *O.J. 

ucts  were  affected  to  some  extent  by  sevi-n  months  outdoor 
exposure,  but  glass  was  unaffected ;  glass  and  hard  rubber 
in  order  were  least  changed  in  dimension  and  weight  on 
immersion  in  various  chemicals,  all  variations  being  less 
than  1%  except  for  hard  rubber  in  an  aromatic  gasoline 


700 
600 
500 
400 
500 
200 
100 


>.OSin 


O6F00MA  TIOM 


load-deformation  cut**  on  low  denaity  balsa 


blend ;  and  balsa  was  much  superior  in  flexural  and  coin- 
pressive  properties. 

The  report  gives  a  full  description  of  test  procedure, 
equipment,  and  methods.    The  procedures  were  similar  in 
general  to  those  described  in  Federal  Specification  L-P-I 
406a.    The  specimens  for  the  various  tests  were  conditioned 
at  77°  F  and  50%  relative  humidity  for  at  least  two  Mavs 
prior  to  test  and  tested  under  those  conditions  (with  a  few] 
exceptions). 

The  thermal  conductivity  tests  were  conducted  in  an  S" 
guarded  hot  plate  apparatus  in  a  manner  similar  to  that 
described  in  Federal  Specification  LLL-F-321b.  The  >IHTI- 
mens,  8"  by  8",  were  dried  in  an  oven  at  140°  to  150°  1-  lor 
about  16  In  prior  to  test. 

For  accelerated  weathering,  the  materials  were  subject, -d 
to  alternate  exposure  to  a  temperature  of  150°  F  in  a  circn-  { 
lating-air  oven  and  to  moisture  in  a  fog  chamber  at  77°  F.  I 
The  daily  schedule  included  2  hr  in  the  fog  chamber,  1  hr 
in  the  oven,  2  hr  in  the  fog  chamber  again,  and  18  hr  in  the 
oven.    The  test  lasted  240  hr. 

Flexure  tests  were  made  with  a  self-aligning,  adjustable- 1 
span  flexure  jig  mounted  in  a  universal  hydraulic  testing; 
machine.  The  compressive  tests  were  also  made  on  a  uni- 
versal hydraulic  testing  machine,  and  special  bearing  blocks 
were  constructed  with  brackets  to  permit  using  a  Soiith- 
wark-IVtrrs  |ila»tii->  rxtrn-iiiiirtiT  for  deformation  meaMire- 
ments.  under  an  arrangement  -u^in^teil  by  I..  K.  11  vile. 
O.  S.  Peters  Co.  >  M- 

KD    NOTE:    The  re«earch  Irxlmn  to  the  renort   aummariied  in   this  ar-1 
tide  waa  •pontorai  by  and  conducted  with  thr  financial  assistance  of  the  V 
National   Advisory   Committee  for   Aeronautics       Material*  were   furnnhed 
ihr.Kiih  the  oxirtwr  of   the  Dow  Chemical  Co.   F..   1.  du   Pont  de   Nemours' 
and  Co..  Inc  .  B    K    (i,..lrirh  Co.,  Goodjrnr  Tire-  and  Rubber  Co.,  Naval] 
Air    Experimental   Station.   Pitlihurf h   Conine  Corn.,  and    U.    S.    Ru 
Co, 


74 


Ft.. \9tTiffi 


Jt'LY 


Coating  Refrigerator  Shelves 

(Continued  from  page  38) 


J 


oven  for  a  30  min.  bake  at  320°  F,  after  which  it  passes 
through  the  second  cooling  tunnel  to  condition  it  for  the 
finish  plastics  coat.  It  then  enters  the  dip  room  and  is  car- 
ried through  the  dip  tank  and  over  the  drain  pan  into  the 
de-tear  area  to  pass  over  the  final  two  de-tear  grids.  It 
then  goes  into  the  finish  oven  and  the  ware  is  baked  for  30 
min.  at  300°  F,  before  being  moved  past  an  inspection  sta- 
tion where  the  completed  shelves  are  inspected,  removed 
from  the  conveyor  by  two  operators,  and  packaged. 

After  the  shelves  are  transferred  from  the  automatic  plat- 
ing and  bonderite  machine  to  the  automatic  plastics  coat- 
ing machine,  they  are  not  touched  by  operators  until  final 
packaging. 

One  control  operator  is  used  to  operate  the  ovens  and  the 
de-tear  equipment  and  to  control  viscosity  in  the  plastics 
coating  tanks.  Temperature  and  viscosity  readings  are 
made  for  both  tanks  hourly,  the  viscosity  of  the  resin  being 
carefully  controlled. 

A  separate  mixing  room  is  located  near  the  dip  room 
where  the  necessary  solvents  and  resins  are  pumped  through 
a  system  of  pipe  lines  to  maintain  the  correct  tank  level  and 
viscosity  readings.  The  solution  in  the  dip  tanks  is  con- 
stantly circulated  in  the  pipe  lines  and  through  two  filter 
presses  in  this  room.  This  insures  a  clean  and  well-agitated 
tank  and  prevents  stratification  of  the  plastics. 

The  development  of  the  coating  process  was  not  without 
difficulties.  On  the  very  first  day  of  production,  a  prominent 
reflow  condition  was  caused  by  a  strong  air  draft  from  the 


main  air  supply  duct  in  the  plastics  dip  room  blowing  on 
shelves  over  the  drain  pan.  To  solve  this  problem,  a  quan- 
tity of  slow  solvents  was  added  for  temporary  relief  pending 
equipment  changes. 

Several  days  later  a  reflow  condition  was  caused  by  high 
room  temperatures.  This  time  the  solution  was  the  in- 
stallation of  baffles  on  the  prime  oven. 

Another  difficulty  was  bringing  the  prime  and  finish  ovens 
up  to  specified  temperatures.  This  was  done  by  adjusting 
the  air  supply  and  exhausts  so  that  the  air  in  the  ovens  and 
the  plastics  dip  room  was  pioperly  balanced. 

Effects  of  Equipment  Changes 

Such  equipment  changes  as  installing  tunnels  over  plastics 
tanks  and  drain  pans  and  bringing  down  the  dip  room  tem- 
peratures by  cooling  the  tunnels  with  outside  air  corrected 
the  reflow  condition  but,  by  reducing  drafts,  slowed  down 
the  coating  operation,  causing  improper  coverage.  Viscosity 
in  both  tanks  was  raised  to  compensate  for  these  changed 
conditions. 

By  increasing  film  coverage  and  viscosity,  however,  a 
longer  drain  time  was  required.  This  resulted  in  a  tear's 
forming  on  the  bottom  of  each  shelf  after  the  shelves  had 
passed  over  the  electrostatic  de-tear  grids.  At  this  time  the 
shelves  were  hung  on  the  hooks  at  a  6°  angle,  and  a  tear 
formed  at  the  lowest  point.  This  condition  was  corrected 
by  hanging  shelves  level. 

The  capacity  of  the  equipment  is  an  average  of  1000 
shelves  per  hour,  or  sufficient  shelves  are  finished  in  16  hours 
for  1400  refrigerators.  The  equipment  operates  very  eco- 
nomically, which  is  indicated  by  the  fact  that  with  only  eight 
direct  labor  employees,  Servel  can  finish  1000  shelves  per 
hour.  Rejects  average  less  than  two  per  cent.  END 


PLASTICS    SCRAP    CENTER 


CEUULOSE  ACETATE 


CELLULOSE  ACETO-BUTYRATE 


POLYSTYRENE 


METHYl  METHACRYIATE     •     POlYVINYl  RESINS,  ETC. 


BOUGHT  &  SOLD 


SELL  US  YOUR  THERMOPLASTIC  SCRAP  .  .  .  rejected  molded 
pieces  or  obsolete  molding  powders. 

We  separate  combined  plastics  scrap  material  as 
we(t  as  remove  metals  and  foreign  particles. 

A.  BAMBERGER 


We  specialize  in  custom  grinding,  magnetizing,  and 
separating. 

Our  reconditioned  molding   powders  are  carefully 
processed  and  delivered  ready  for  use. 


44  Hewes  Street 
Brooklyn  11,  N.  Y. 


Phone:  EVergreen  7-3887 
Cable :  Chemprod  Brooklyn 


JULY  1946 


PLASTtCS 


75 


Know    your  .Me/amines 

i  Continued  from  payc  •*"  > 


de»ired.  When  this  property  must  be  or  can  advantageously 
be  combined  with  other  physical  and  chemical  properties 
this  material  is  extremely  effective. 

The  Army  Medical  Corps  adopted  service  trays  made  of 
this  material  for  use  in  hospitals  and  on  hospital  ships  and 
trains,  because  of  their  light  weight,  strength,  hard  surface, 
and  absence  of  odor  and  taste.  A  special  compound  was 
developed  for  the  Army,  consisting  of  a  melamine  resin 
modified  with  a  small  amount  of  phenolic  resin,  to  incor- 
porate additional  strength.  The  same  qualities  make  the 
material  excellent  for  peace-time  uses.  Already  an  extensive 
line  of  hospital  service  units  have  been  manufactured  and 
succe>sfully  distributed. 

A  manufacturer  of  heavy-duty  mining  machinery  required 
an  insulating  material  which  combined  resistance  to  shock 
with  outstanding  electrical  properties.  After  considerable 
in\i--tiK.-ition.  rag-filled  melamine  was  selected  for  use  on 
all  electrical  control  mechanisms  mounted  on  his  machinery. 
Outstanding  qualities  achieved  were  high  arc  resistance, 
heat  resistance,  exceptional  strength  and  shock  resistance 
\i\u^  the  unique  characteristic  of  resisting  a  nitrate  deposit 
even  when  exposed  to  an  electric  arc  in  the  presence  of 
moisture.  This  last  point  is  particularly  important  in  that 
electrical  controllers  on  mining  machinery  are  housed  in 
explosion-proof  cases  for  protection  from  the  dirt  and 
moisture  always  present  in  a  mine  tunnel. 

Chopped  cotton-filled  melamine  has  been  used  for  a  collar 
on  a  bru>h  *tuH  holder  on  heavy  duty  electric  motors.  The 


Mixer  discharging  melamine  molding  compound 

plastics  joins  two  metal  parts  and  at  the  same  time  provides 
superior  electrical  insulation. 

Originally  the  material  was  supplied  in  two  colors,  black 
and  opaque  mottled  white.  As  a  result  of  many  inquiries 
for  consumer  applications  requiring  color,  rag-filled  mela- 
mine molding  materials  are  now  available  in  a  range  of 
colors  including  white,  blue,  red,  green,  brown,  black. 

A  recently  introduced  melamine  with  a  wood-flour  filler 
combines  nearly  all  of  the  well-known  electrical  properties 
of  the  mineral-filled  products  with  lower  specific  gravity  and 
excellent  molding  characteristics.  Suitable  for  either  com- 
pression or  transfer  molding  techniques,  wood  flour-filled 


PLASTIC 


SES  INC. 


129    Bloomfleld   Ave. 

Bloomfield, 

New  Jersey 


Our  9  and  16  oz.  Injection  presses,  150 
and  300  ton  Compression  presses  are 
SWINGING  INTO  PRODUCTION. 

Newly  designed  hangers  —  stronger  and 
more  pleasing  to  the  eye;  chime  housings  — 
Intricate  yet  inexpensive;  numerous  other 
products  hitherto  unknown  to  the  Plastic 
mart  ...  all  these  and  more,  pour  forth 
with  the  imprint  of  Plastic  Enterprises  Inc 

Call  upon  us  with  an  idea,  a  design  or  a 
sample  .  .  .  we  will  work  from  any  stage 
of  development  and  give  you  a  completed 
product.  .  .  . 

Climb  aboard  and  swing  to  the  top  with 
PE  molded  products. 


MOLD   DESIGNERS   &   BUILDERS      /  f> 

F 
eri  \Si 


ana    LompreAAon 


WlotJ* 


P  I.  AST  11  S 


JULY  1'Mfi 


Properties 


"Melmac" 

Values 

Wood-Filled   Mineral  Filled      Rag  Filled 
(Grade  1500)    (Grade  592)  (Grade  3020) 


1  45.  . 

,  1.78.  . 

1.50 

Flexural  strength  (psi)  

,...11,000... 

9,280.. 

.  .  .  1  2,000- 

1  5,000 

Impact  strength  (ft-lb  per  notch 

in.  Izod)  

.0.30-0.34... 

0.326.. 

0.5-0.9 

Water  absorption  (%  on  24  hr 

immersion)  

.0.34-0.40... 

0.13.., 

.0.30-0.60 

Arc  resistance  ASTM  

...95-130... 

..125-135... 

..115-125 

Dielectric  strength  (vpm)  S/T.  .  .  . 

..380-450... 

400... 

..250-350 

Dielectric  constant  (60  cycles)... 

6.5.  .  . 

7.7.. 

8.3 

Power  factor  (60  cycles)  

0.05... 

0.11... 

.0.08-0.11 

Note:  For  a  much  more  complete  list  of  properties,  see  the  Second  Annual  Directory 
(March,  1 946)  issue  of  pfaitict. 

nielamine  is  very  satisfactory  for  general  applications  in  the 
electrical  insulation  field.  This  compound  is  well  suited  for 
such  items  as  stove  switch  blocks,  circuit  breakers,  con- 
nector plugs,  and  other  industrial  and  electrical  molded  parts 
where  arc  resistance  and  heat  resistance  are  required.  END 


Injection  Mold  Design 

{Continued  from  page  56) 


J 


~top  should  be  supplied  to  prevent  the  plate  from  coming 
too  far  forward  and  falling  off  the  guide  pins. 

Knockout  sleeves  offer  a  third  method  of  ejection.  They 
are  commonly  used  on  items  such  as  the  illustrated  knob 
(Fig.  6).  Sleeves  add  considerably  to  the  cost  of  the  die, 
and  tend  to  cause  higher  die  maintenance,  but  often  they 
are  the  only  logical  solution  to  the  ejection  problem.  They 
>linuld  be  used  only  after  the  possibility  of  using  knockout 
piiis  and  stripper  plate  construction  has  been  thoroughly  con- 
sidered and  found  to  be  inadvisable.  (TO  BE  CONTINUED) 


You're  Assured  of 

DEPENDABLE 

Heavy  Duty  Compression 

MOLDS 

with 

AJAX  6F  STEEL 


HERE'S  WHY! 

AJAX  "61"  is 


•  ELECTRIC   FURNACE    QUALITY 

•  EASILY   MACHINED 

•  FREE   OF   FLAKES,  CRACKS 

and    STRINGERS 


Ajax  "61"  Steel  in  Ajax  forged  mold  blanks  means 
real  economy  in  compression  molds  specified  for 
heavy  duty.  Ajax  Steel  is  hardened  to  your  job  speci- 
fication and  is  guaranteed  free  of  defects  in  material 
and  workmanship.  Ajax  is  proud  of  its  record  and 
reputation  among  plastic  molders  for  trouble-free, 
high  quality  mold  steel. 

We  invite  you  to  bring  your  mold  steel  problems  to 
AJAX  Steel  and  Forge  Company. 


Valuable 


Write  our  Service  Department  for 
your  copy  of  the  famous  "AJAX 
BLACK  BOOK."  Full  of  useful  in- 
formation, steel  weights,  standard 
specifications,  conversion  tables, 
etc. 


Booklet 


i  AJAX 


205ADAIRST.      D  ETRO  I  T  7,  M  I  C  H. 


JULY  1946 


PLASTICS 


11 


Bridgeport  Fabrics  uses  "Saian"  belting  in  the  manufacture 
of    beautiful,    colorful,    easy-to-clean    upholstery    materials 


New  Beauty  in  Fabrics 


T'H'i.H.  watiT|>r<nif  fabrics  woven  of  Saran  monofila- 
tnents  i  *,-,-  rover  photograph )  in  a  variety  of  patterns 
and  colors  attracted  more  than  passing  interest  at  the  recent 
Plastics  Exposition  in  New  York  City,  and  their  unusual 
beauty  and  long  wearing  qualities  an-  proof  that  home- 
makers  can  look  forward  with  enthusiasm  to  a  new  type  of 
fabric. 

Saran.  manufactured  by  the  Dow  ("lu-mical  Company,  is 
a  vinylidenc  chloride  resin  with  petroleum  and  brine  as  its 

"Luraite"  fabric  Is  used  in  handsome  "Detrola"  radio  cabinet 


major  raw  materials,  I'nique  among  its  properties  is  its 
resistance  to  chemicals  and  acids,  and  chemical  combina- 
tions. This  chemical  resistance,  and  the  waterproofnes>  and 
toughness  of  the  parent  material,  are  inherent  in  the  mono- 
filaments.  These  properties  mean  beautiful  fabrics  which 
will  take  considerable  punishment,  are  easily  cleaned  with  a 
damp  cloth,  and  will  not  stain  or  fade  under  ordinary  usage 
Saran  fabrics  possess  a  sheen  and  brilliance  which  imparts  a 
"new"  look  throughout  their  use. 

The  monofilaments  range  in  size  from  .003"  to  .053"  in 
dia  and  should  not  be  confused  with  multifilaments*  used 
in  other  synthetic  dress  and  hosiery  materials.  Compared 
with  multifilaments,  the  monofilaments  produce  a  strong, 
smooth-surfaced  rather  stiff  fabric. 

Saran  fabrics  for  the  home  range  from  finer  wea\e>  fur 
interiors  to  those  woven  of  larger  monofilaments  for  play- 
room, porch  and  sunroom  upholstery.  They  are  being  sp<-oi- 
fied  for  shipboard,  automobile  and  plane  uphoKt<r\.  .mil 
Arnold  daray.  maker  of  women's  handbags,  recently  chose 
them  for  his  spring  line.  He  was  the  first  to  carry  an  in- 
formative laln-l  which  introduced  the  fabrics  directly  to  the 
roiisiiinrr.  Many  types  of  Saran  fabrics  are  on  the  design 
boards  for  shoes  and  luggage,  while  their  long  wearing 
qualities  and  smooth  .surfaces  make  them  ideal  upholstery 
material  for  bus.  subway,  railway  and  theatre. 

A  new  type  Saran  fabric,  Lumilc.  has  l>een  developed  for 
i.idio  cabinets  by  Chicopec  Manufacturing  Coni|>any.  with 
(Continued  on  foge  101) 

•Multitil.mrni.   ratMurc   (ran   5   to  26   microni  in   di*.     A   micron   ii 
1/JS.OOOth  of  an  inrh 


78 


.iri.v  1'iifi 


Statistical  Data 

Consumption  and  shipments  rise  in 
March/  polystyrene    continues    gain 


AS  FORETOLD  last  month,  the  upward  trend  in  plastics 
and  synthetic  resins  shipments  and  consumption  continued 
in  March.  The  figures  for  February  and  March  are  not  wholly 
comparable,  since  one  more  manufacturer  reported  in  March 
than  in  February.  The  one  company,  however,  accounts  for  only 
a  small  portion  of  the  over  seven  million  pounds  difference  in 
the  figures  for  the  two  months. 

The  figures  for  polystyrene  continue  to  show  a  phenomenal 
increase,  the  March  total  exceeding  four  million  pounds  or  a 
million  pounds  over  the  shipments  and  consumption  in  February. 
This  represents  a  33%  increase  in  only  a  month's  time. 

The  next  greatest  increase  involved  the  vinyl  resins,  support- 
ing the  common  claim  that  vinyl  sheeting  and  film — and  other 
forms  as  well — are  in  great  demand. 

There  were  decreases  in  only  three  classifications :  nitrocel- 
lulose, rods  and  tubes ;  phenolic  and  other  tar  acid  resins,  all 
other  (dry  basis)  ;  and  urea  and  melamine  resins,  all  other  (dry 
IIHMS).  The  differences  here  are  little  more  than  negligible. 

These  statistics  from  the  Bureau  of  the  Census  represent  the 
shipments  and  consumption  of  plastics  and  synthetic  resins  as 
reported  by  78  manufacturing  companies  and  company  depart- 
ments. This  is  an  increase  by  one  over  the  number  of  manufac- 
turers reporting  last  month.  Data  for  synthetic  resins  used  as 
protective  coatings  are  not  included.  Shipments,  for  the  purposes 
of  the  report,  include  data  for  plastics  and  resins  manufactured 
I iy  the  reporting  companies  or  company  divisions  and  shipped  to 
outside  users.  Consumption  refers  to  the  quantities  of  plastics 
and  resins  manufactured  and  used  by  the  reporting  companies 
and  company  divisions.  END 


Plastics  and  Synthetic  Resins  Shipments  and 
Consumption  (Ib) 


Item 


March 
1946 


February 
1946 


Cellulose  acetate  and  mixed  ester  plastics1 

Sheets 

Continuous  (under  .003  gauge) 

Continuous  (.003  gouge  and  upward).  . . . 

All  other  sheets,  rods,  and  tubes 

Molding  and  extrusion  materials 

Nitrocellulose  plastics' 

Sheets 

Rods  and  tubes 

Phenolic  and  other  tar  acid  resins 

Laminating  (dry  basis) 

Adhesives  (dry   basis) 

Molding  materials' 

All  other  (dry  basis)3 

Urea  and  melamine  resins 

Adhesive  (dry  basis) 

Textile  and  paper  treating  (dry  basis) 

All  other  (dry  basis)3 

Polystyrene 

Vinyl  resins 

Sheeting  and  film' 

Textile  and  paper  coating  resins  (resin  content) 

Molding  and  extrusion  materials' 

Adhesives  (resin  content) 

All  other  (resin  content)3 

Miscellaneous  plastics  and  resins 

Molding  and  extrusion  materials'    7 

All  other  (dry  basis)3    8 


656,114  596,355 

677,978  541,542 

417,599  410,867 

6,503,781  6,024,690 


911,081 
609,841 


822,120 
613,116 


2,052,005      1,806,919 

1,194,3892       991,233 

12,286,204   10,606,487 

4,229,231      4,331,994 

3,224,9594  2,794,506 

1,034,940  995,776 

130,296  167,559 

4,011,334  3,007,122 


2,161,230 

1,688,890 

6,664,970 

640,6355 

659,178 

5,434,228 
2,731,042 


1,665,666 

1,034,511 

5,910,429 

•390,171 

589,224 

4,498,719 
2,612,440 


TOTAL 57,917,925  50,411,446 

"Revised.  'Includes  fillers,  plosticizers,  and  extenders.  3Data  for  one  company  not  pre- 
viously reporting  are  included;  therefore,  these  data  are  not  comparable  with  data  far 
previous  months.  -Excludes  data  for  protective  coating  resins.  'Includes  operations  for 
one  establishment  not  previously  reporting;  however,  this  does  not  appreciably  affect 
the  comparability  of  the  statistics  for  previous  months.  Proportion  of  estimate,  4%. 
'Proportion  of  estimate,  9%.  'Includes  data  for  ethyl  cellulose,  urea  and  melamine, 
acrylic  acid  and  miscellaneous  molding  and  extrusion  materials.  "Includes  data  for  pe- 
troleum resins,  acrylic  acid  ester  resins,  mixtures,  and  miscellaneous  synthetic  resin 
materials. 


Ingenious  New 

Technical  Methods 


To  Help  You  with  Your 
Reconversion  Problems 


New  Brush-Backed,  Strip-Fed  Abrasive 
Wheel  Deburrs,  Sands  Any  Surface! 


For  sanding  in  and  around  the 
most  irregular  contours — for  de- 
burring  parts  too  large  to  be 
tumbled — for  removing  rust,  paint 
and  imperfectionsfrom  wood,  plas- 
tics, rubber,  earthenware  and 
metals  — the  new  Sand-O-Flex 
brush-backed  abrasive  wheel  is 
MOST  PRACTICAL. 

The  central  magazine  houses  a 
strip  abrasive  cartridge,  to  be  fed 
out  as  needed  in  front  of  the  eight 
brushes  which  "cushion"  the  abra- 
sive, and  force  it  evenly  over  the 
most  difficult  surfaces.  The  Sand- 
O-Flex  comes  in  3  sizes,  and  is 
adaptable  to  any  stationary  or 
portable  motor  shaft,  with  speeds 
up  to  1750  RPM.  Abrasives  are 
available  in  grits  for  every  need. 

To  help  speed  production  in  dry, 
dusty  work  atmosphere,  many 
mills  and  factories  urge  workers 
to  chew  gum  to  help  relieve  dry 
throat.  The  reason:  Because  dust 
causes  throat  irritation  and  dry- 
ness—but  chewing  Wrigley's 
Spearmint  gum  helps  keep  work- 
ers' mouths  moist  and  fresh.  The 
result:  Reduced  work  interruptions 
and  "time  outs"  to  the  drinking 
fountain.  Even  when  workers' 
hands  are  busy,  they  can  refresh 
as  they  work  "on  the  job."  And 
the  chewing  action  helps  keep 
workers  alert  and  wide-awake. 

You  can  get  complete  information  from 

the  Sand-O-Flex  Corporation, 
4373  Melrose  Ace.,  Los  Angeles  27 ,  Cat. 


Abrasive  Cartridge  Shown  Open 


AA-74 


JULY  1946 


PLASTICS 


79 


FOR INDUSTRY 


^r 

Aoprox.motcd  from  of- 
ficial, governmental,  and 


ofK«r   reports 


A  LOGICAL  AND   PROFITABLE 
LOCATION  FOR  YOUR  PLASTICS  PLANT 

Consider  the  unique  advantages  of  a  Grays  Harbor  location 
for  a  wood  plastics  plant.  Abundant  raw  material  for  lonp 
range  planning — standing  virgin  timber  that  is  the  fastest 
growing  in  the  western  hemisphere — waste  material  from 
existing  mills!  A  huge  supply  of  high-grade  industrial  water! 
Cheap  industrial  electric  power!  A  surplus  of  efficient,  stable 
labor!  Low  cost  transportation — three  transcontinental  rail- 
roads— one  of  the  finest  deep-sea  poets — a  new  multi-mil- 
lion dollar  airport — excellent  arterial  highways. 

If  you  are  planning  a  program  of  expansion  or  intend  to  in- 
augurate a  wood  plutics  operation,  be  sure  to  investigate  the 
assets  you  will  immediately  gain  with  a  Grays  Harbor  loca- 
tion. Well-financed  civic  organizations  such  as  Grays  Harbor 
Industries,  Inc.,  are  eager  to  cooperate  with  outside  capital 
and  management.  Detailed  information  pertinent  to  your 
problems  is  available.  Write  to  the  address  below  for  com- 
plete statistical  facts ...  or  if  you  prefer,  a  personal  represen- 
tative will  call  on  you. 


GRRYS  HflRBOR 

H     I 

Sponsored  By 

GRAYS  HARBOR  INDUSTRIES,  INC. 

ABERDEEN,  WASHINGTON 


ENGINEERING 

Jtetie* 


By  LEWIS  WINNER 


Threads  and  Filaments 

When  wartime  conditions  made  it  difficult  to  secure  a  free  flow 
of  i. .lion.  silk,  flax  and  other  fabric  fibers  of  nature,  plaMic- 
came  to  the  rescue  not  only  in  this  country,  but  in  Great  Britain, 
where,  il  has  recently  been  disclosed,  a  process  providing  threads 
and  filaments  from  polyvinyl  alcohol  was  developed.  Conci-iv-.il 
by  Donald  Leonard  Wilson  of  Coventry,  England,  the  process 
provides  for  the  extrusion  of  an  aqueous  solution  of  water- 
soluble  polyvinyl  alcohol  into  a  88%  to  96%  organic  liquid  bath. 

The  organic  liquid  used  removes  the  water  from  the  aqueous 
solution  of  [K.lyvinyl  alcohol.  Acetone,  ethyl-lactate  and  ethylcne 
glycol  monoethyl  ether  are  some  of  the  liquids  that  can  be  used 
for  this  purpose. 

Production  of  Solution 

In  actual  production,  i>olyviiiyl  alcohol  is  dissolved  in  water 
by  warming  to  a  temperature  of  60°  C,  providing  a  solution  of 
14%  concentration  and  a  viscosity  of  3  poises  at  25°  C  This 
solution  is  cooled,  filtered  and  de-aerated,  and  extruded  through 
a  jet  containing  200  holes,  each  .003"  in  diam,  into  a  bath  of  28* 
to  30"  C,  composed  of  94%  acetone  and  6%  water. 

As  the  thread  is  formed  it  is  passed  over  a  roller  operating  at 
a  speed  of  about  22  fpm  and  then  through  a  bath  of  50%  hy-  j 
droxy-ethoxy  ethyl  ether  and  50'V  water  maintained  at  a  tem- 
perature of  29°  to  31°  C.   The  thread  is  then  wound  on  a  spool, 
at  a  rate  of  about  120  fpm.  or  5.5  times  its  former  length.   The 
spools  are  placed  in  a  chamber  having  temperature  of  60°  C,  for  ' 
drying.   Threads  produced  in  this  manner  have  a  denier  of  124, 
dry  tenacity  of  2.52  grams  per  denier  and  dry  extensibility  of 
12.4%. 

Unfortunately,  the  threads  produced  by  this  process  are  w -ali- 
ened by  cold  water  and  dissolved  by  hot  water.  Resistance  to 
such  water  action  can  be  provided  by  treating  the  threads  with 
formaldehyde. 

Lustrous  polyvinyl-alcohol  threads  with  a  denier  of  68  and 
dry  tenacity  of  2.03  grams  per  denier  have  likewise  been 
produced. 

Collapsible  Tubes 

With  plastics  rapidly  becoming  a  basic  packaging  material  for 
cosmetics,  dental  cream,  and  pastes,  adhesives.  ointments  and 
greases,  there  has  been  int-.-Ti-.ivt-  research  to  provide  improved 
and  reinforced  thin-walled  collapsible  tubes  to  accommodate 
these  cream-like  substances. 

Older-type  plastics  tubes  have  suffered  from  weakened  walls 
because  the  molten  thermoplastics  material,  usually  viscous  in 
nature,  would  not  flow  readily  to  the  narrow  sections  of  the  mold 
cavity  since  it  would  chill  upon  contact  with  the  closely  spaced 
walls  and  thicken,  harden  or  even  solidify.  Heating  has  been 
attempted  hut  without  great  success. 

Rotating  Mandrel 

\  recent  solution  to  the  problem  has  been  provided  by  Russell 
K.  I'.r.i-Mi.iw.  Midland,  Mich.,  who  uses  a  rotating  mandrel 
which  generates  {fictional  heat  between  itsel{  and  the  molding 
charge.  The  heat  generated  by  the  friction  causes  the  molding 
charge  to  soften  and  melt  or  flow  under  continued  pressi; 
the  mandrel,  which,  when  applied  in  a  mold  cavity  of  a  die 
block,  is  advanced  into  the  cavity  and  pressed  onto  the  molding 
charge.  The  mandrel  may  be  rotated  at  from  500  to  2500  rjmi. 
depending  on  mandrel  diam.  pressure  exerted  on  the  plastics  and 
nature  of  the  plastics  itself. 

This  process  is  particularly  useful  lor  circularly-formed  ob- 
jectt  which  require  wall  thickness  from  .25"  to  .001". 

The  rotating  procedure  has  also  been  effectively  applied  t<>  the 
die  Mock,  with  the  mandrel  remaining  stationary.  In  other  tests, 
both  die  block  and  mandrel  have  been  rotated  in  opinn.it r  direc- 
tion* to  provide  a  wide  area-flow  ..(  plastics  mi.,  the  cavity  walls. 


PLASTICS 


JULY  1946 


Cooling  Problems 

Plastics  cooling  has  been  a  pet  project  of  many  researchers. 
While  cooling  of  plastics  may  seem  to  be  quite  a  simple  proce- 
dure, many  complex  distortion  and  deformation  problems  do  ap- 
pear during  the  cooling  operations.  To  overcome  such  problems, 
Frank  G.  Back,  New  York  City  has  developed  an  energetic-cool- 
ing-action system  which  is  applied  immediately  after  material 
leaves  the  die  head  and  is  directed  along  all  exposed  surfaces. 
The  cooling  is  provided  by  a  stationary  cooling  track,  composed 
of  heat-conducting  material,  directly  above  the  conveyor  belt. 
An  air  chamber,  operated  by  air  under  pressure,  surrounds  the 
track,  all  surfaces  of  which  are  exposed,  thus  providing  excellent 
heat  radiation. 

In  formerly-used  conveyer-belt  cooling  systems,  air  cooling 
jets  have  been  placed  at  intervals,  and  in  some  instances  water 
has  been  used  to  remove  heat.  Results,  however,  have  not  been 
too  successful  because  of  the  spotty  application.  This  is  particu- 
larly true  in  cooling  irregular  sections  with  ribs  at  angles  to  each 
other(  as  in  variations  of  H  and  U  shapes)  resulting  in  deformed 
or  arched  forms  requiring  annealing  treatments  to  straighten. 

The  use  of  the  energetic-cooling  action  also  prevents  deforma- 
tion and  distortion  of  simple  extruded  material. 

It  was  found  that  lubrication  was  essential  in  maintaining  a 
free  flow  of  the  extruded  material  over  the  cooling  track. 
Graphite  and  pressed  materials  with  a  coal  or  petroleum  residue 
proved  to  be  excellent  for  lubrication  applications,  graphite  in 
particular  offering  the  necessary  heat  conductivity,  a  fair  degree 
of  porosity,  and  active  lubricating  properties.  It  is  also  easily 
machined.  The  graphite  materials  used  included  binders  such  as 
resin,  graphite  clay  and  a  mineral  or  vegetable  oil,  etc. 

Safety  Gfass  Reinforcement 

The  use  of  vinyl  acetals  as  a  reinforcement  in  safety  glass 
represented  a  striking  advance  in  the  art.  Now  the  vinyl-acetal 
process  to  replace  the  originally-used  nitrocellulose  has  been 
further  improved  by  plastics  compositions  of  vinyl  acetal  homo- 
geneously blended  with  an  ester  of  a  glycol  and  mixtures  of 
acids.  This  process  originated  by  Wm.  H.  Lycan,  Milwaukee, 
and  adopted  by  the  Pittsburgh  Plate  Glass  Company,  provides 
for  the  plasticizing  of  a  flexible  sheet  of  polyvinyl  acetate  resin 
with  about  25%  to  45%  of  an  ester  of  a  dihydroxy  ethyl  ether 
alcohol  containing  two  to  three  ethyl  groups,  and  a  mixture  of 
branched  chain  acids  obtained  by  air  oxidation  of  an  open-chain 
petroleum  hydrocarbon  of  about  45°  Be. 

For  test  purposes,  an  interlayer  sheet,  .015"  thick,  was  laminated 
between  plates  of  glass  12"  square,  each  plate  being  about  7/64" 
thick,  and  the  glass  was  subjected  to  the  impact  of  a  freely  falling 
steel  ball,  weighing  l/2  Ib,  at  varying  temperatures.  A  height  of 
50  ft  (at  70°  F)  was  reached  before  the  glass  broke  down.  In 
this  particular  sample  the  interlayer  composition  consisted  of 
vinyl  acetal  containing  about  31%  of  triglycol  ester  of  an  acid 
fraction  with  an  average  of  8  carbon  atoms  per  molecule.  Di- 
glycol,  tetraglycol  and  polyglycol  can  be  substituted  for  triglycol. 

The  original  nitrocellulose  safety  glass  compositions  tended 
to  discolor  under  light.  The  new  materials  are  clear,  and  are 
resistant  'to  discoloration  by  ultraviolet  light  and  to  moisture- 
penetration. 

Material  Blending 

Properties  of  many  types  of  plastics  have  prompted  their  use 
as  material  blends  to  improve  coagulation,  hardness  and  abrasive 
resistance.  One  type  of  plastics  that  has  been  used  quite  effec- 
tively for  such  blending  has  been  vinyl  resin. 

Gerry  P.  Mack,  Jackson  Heights,  New  York,  has  prepared  a 
stable  liquid  vinyl  resin  dispersion  which  can  be  blended  with 
rubber  latex  to  form  a  substantially  stable  emulsion  and  provide 
articles  with  high  modulus,  good  tensile  strength,  elongation  and 
hardness. 

Vinyl  resin  dispersions  can  be  blended  with  rubber  latex  at  a 
rate  of  between  8  and  40  parts  of  the  dispersion  to  about  100 
parts  of  solid  rubber  particles  dispersed  in  water. 

In  producing  a  sample,  15  g  of  monomeric  methacrylic  acid 
were  mixed  with  108  g  of  monomeric  acrylic  nitrile  and  .072  g 
of  benzoyl  peroxide,  and  the  mixture  refluxed  for  one  hour.  The 
40  g  of  the  dispersion,  smooth  and  milky  in  appearance,  were 
stirred  into  166  g  of  a  60%  centrifuged  rubber  latex.  Heating 
in  a  closed  container  for  two  hours  at  212°  F  followed.  The  re- 
sulting material  was  completely  coagulated,  washed  and  dried, 
providing  a  tough  rubbery  film.  END 


176  COMBINATIONS     OF 
STANDARD    MOLD   BASES 


MOLD- 
MAKERS' 
SUPPLIES 


EJECTOR 
PINS 


DME    NEWS    will    fa*    mailed 
you  monthly  on  request — FREE  I 


DETROIT      MOLD 
ENGINEERING     COMPANY 


6686    E.   McNICHOLS   RO. 


DETROIT    12,   MICHIGAN 


JULY  1946 


PLASTtCS 


81 


INDUSTRY  HIGHLIGHTS 


A  new  departure  in  hard-surface  floor  covering  has  been 
announced.  Manufactured  by  Sloane-Blabon  Corp.,  Trenton. 
X.  I  ,  under  technical  supervision  of  B.  F.  Goodrich  Co.,  and 
using  the  tatter-named  company's  raw  material  and  its  trade 
name  of  Koroieal,  the  material  is  said  to  embody  the  color- 
ability,  durability,  and  resistance  to  flame,  wear  and  weather, 
attributed  to  Koroseal  in  many  other  applications.  Available 
in  square  flexible  tile  form  and  in  a  wide  range  of  solid  colors, 
the  material  is  to  be  formally  introduced  at  the  midsummer 
furniture  markets  in  New  York,  Chicago,  Los  Angeles,  and 
San  Francisco,  according  to  announcement. 

Removal  to  its  new  plant  at  1026  Venice  Blvd.,  Los  Angeles, 
has  been  announced  by  Crystalline  Plastics  Co. 

Decorative  Formica  material  is  to  be  produced  in  Britain 
by  DeLaRue  Insulation  Ltd.,  London,  under  a  licensing  ar- 
rangement with  The  Formica  Insulation  Co.,  according  to  a 
recent  announcement.  J.  A.  Warwick,  British  engineer  and 
plant  manager  for  the  DeLaRue  Co.,  came  to  the  United  States 
!>ring  to  spend  a  month  at  Formica's  Cincinnati  plant  in 
order  to  study  the  manufacturing  processes. 


to  the  chapter,  the  first  covering  mechanical  assembly  by  such 
means  as  rivets,  bolts,  screws,  and  inserts :  the  second  dealing 
with  the  cementing  of  thermoplastics ;  and  the  third,  the  cement- 
ing of  thermosetting  plastics.  Discussions  of  heat  welding  and 
cementing  of  plastics  to  other  materials  are  also  included  in  the 
chapter,  which  is  adequately  supplied  with  illustrations. 


Announcement  of  the  formation  of  Wales-Strippit  of  Can- 
ada Ltd.,  with  plant  and  sales  office  at  85  Cannon  St.,  \Vc>t, 
Hamilton,  Ont,  under  managership  of  William  Beattie,  has 
been  made  by  George  F.  Wales,  president  of  Wales-Strippit 
Corp. 


A  limited  printing  of  advance  copies  of  the  technical  hand- 
book which  is  being  developed  by  the  Engineering  and  Technical 
Committee  of  the  Society  of  the  Plastics  Industry  will  be  avail- 
able for  distribution  by  July  IS,  according  to  announcement 
from  the  Society. 

This  latest  section  of  the  handbook,  titled  "Cementing  and 
Assembly  of  Plastics,"  deals  with  the  subject  of  basic  processes 
of  joining  and  bonding  plastics  pieces.  There  are  three  parts 


Insect  screening  for  doors  and  windows,  which,  it  is  said, 
will  not  sag  or  bulge  and  will  resist  repeated  impact  such  as  this 
material  may  encounter  in  daily  usage,  was  featured  by  the 
Lumite  Division  of  Chicopee  Mfg.  Corp.  at  the  recently-held 
National  Modern  Homes  Exposition  in  New  York.  A  dramatic 
demonstration  of  the  strength  and  resilience  of  Lumite  insect 
screening  was  supplied  by  the  company  by  dropping  a  5-lb  iron 
ball  at  6-sec  intervals  on  a  section  of  the  material. 

Woven  of  Dow  Saran,  other  advantages  listed  for  Lumite 
screen  cloth  include  its  easy  cleanability.  its  rust-proof,  stain- 
proof,  and  acid-resistant  qualities,  and  the  fact  that  it  does  not 
require  painting. 

Also  featured  in  the  Chicopee  Mfg.  Corp.  exhibit  was  woven 
Lumite  fabric  which  is  finding  a  variety  of  uses  in  drapery  and  ] 
upholstery  applications. 


Entry   into  the   transparent   film   printing  and  processing 
business  has  been  announced  by  Plastics  Guild  Corp.,  Paterson, 


CONVERT    YOUR 


HYDRAULIC  PRESS  INTO  A 
VERTICAL  PLASTIC  INJECTION 
MOLDING  PRESS  IN  A  FEW  HOURS 

Unit  is  easily  removed  and  your  press  reconverted  to  a  hydraulic 
press.  We  require  the  dimensions  of  your  press  between  posts, 
front  to  back,  and  left  to  right,  daylight,  size  of  ram,  and  ram 
pressure  used. 

The  following  chart  will  show  the  capacity  of  your  press  at 
30,000  ps!  injection  pressure. 


400  to*  HY-SfftD  p,,»  ./rn  3t  iJ2"  Utttn  «"  dty 
light.  Pitlon  urn  tonitrltd  into  »  24  01.  injtcHon  m«- 
ckint  tt  t  toil  of  liSOO  for  comp/*f*  conrtm'on. 


Torn 

Oi. 

Molding  area  sq.  in. 

50 
75 
100 
ISO 
200 
250 
300 
400 

2 

3 

4 
6 
8 
10 

12 

16 

7  to    20 
10  to    30 
15  to    40 
20  to    60 
25  to    80 
30  to  100 
40  to  120 
60  to  180 

FLUID  POWER  AIR  OPERATED  PUMP 

185  gallon!  per  minut*   at  200   pti  3000  pti  accumulated   prtttur*   cut* 
in  at  200  poundt  automatically.    Unit  it  in  a   iteel  cabinet  with  all   the 
control!  on   the  front   panel. 

*     OUR  2  02.   INJECTION   MOLDING   MACHINE  CAN   BE   HAD   IN   30   DAYS.  WRITE   NOW. 


1715  W.  Lake  St. 


HY-SPEED  PRESS  COMPANY 

Chicago  12,  Illinois 


Haymarket  3161 


n 


JULY  1946 


X.  T.  A  new  process  developed  by  the  company's  research  de- 
partment is  described  as  softening  the  film  while  under  tension, 
embodying  the  color  print  within,  thereby  making  the  colors  an 
integral  part  of  the  film.  It  is  further  announced  that  in  order 
to  handle  this  additional  phase  of  its  work,  Plastics  Guild  Corp. 
has  opened  a  new  plant  in  Paterson. 


A  plastics  sheeting  which  is  described  as  being  pliable,  tough 
and  washable,  scuff-proof  and  with  high  resistance  to  snagging, 
tearing  or  puncturing,  is  being  produced  by  United  States  Rub- 
ber Co.  for  such  applications  as  handbags,  belts,  billfolds,  to- 
bacco pouches,  brief  cases,  etc.  Known  as  U.  S.  Royalene,  the 
sheeting  is  made  without  fabric  backing  or  surface  finishing 
coat,  according  to  description,  can  be  produced  in  a  smooth 
finish,  embossed  finish,  or  press  polished,  in  a  range  of  colors 
from  light  to  dark  tones  and  in  several  gages  and  pliabilities, 
depending  upon  the  requirement.  High  resistance  to  stains, 
and  imperviousness  to  alcohol,  perspiration,  oil,  grease,  mildew, 
and  most  acids,  are  additional  qualities  claimed  for  this  material. 


A  new  hot-melt  plastics,  known  as  Nuplamold,  has  been  de- 
veloped by  New  Plastic  Corp.,  Hollywood,  Calif.,  for  casting 
complex  shapes  of  plaster,  cement,  plastics,  and  alloys.  Items 
with  delicate  or  complicated  undercuts  can  be  accurately  cast  in 
this  new  flexible  mold,  which  can  be  elongated  to  remove  intri- 
cate castings  without  damage,  it  is  claimed. 


Described  as  employing  synthetic  resins  to  bind  the  color 
in  original  pigment  form  to  and  throughout  fabrics,  a  new 
process,  known  as  Color  Bond  resin  pigment  dyeing,  has  been 
developed  and  patented  by  Riverside  &  Dan  River  Cotton  Mills, 
Inc.,  Danville,  Va.  A  variety  of  newly-dyed,  Dan  River  Color 
.Bond  fabrics  were  recently  displayed  at  a  special  showing  in 
Gimbel  Brothers  Plastics  Exposition,  Philadelphia,  which  was 
jointly  sponsored  by. the  Gimbel  company  and  the  Philadelphia 
chapter  of  the  SPI. 


Purchase  of  the  Molded  Products  Division  from  the  Wm.  L. 
Gilbert  Clock  Corp.  has  recently  been  announced  by  The  Animal 
Trap  Co.  of  America,  Lititz,  Pa. 


German  Plastics 

(Continued  from  page  66) 


35%  total  oils  and  could  be  applied  on  metal.  It  was  good 
for  inside  work,  but  had  too  much  resin  for  outside  work. 
For  outside  work  they  first  used  Eistan  Firnis  with  50% 
heat-bodied  linseed.  Later  they  went  to  30%  oil,  20%  tall 
oil-linseed  modified  phthalate. 

The  water  emulsions  of  alkyds,  sold  for  some  years  under 
the  name  of  Membrandt,  were  excellent  for  plaster  and 
wood.  There  seemed  to  be  a  slow  but  steady  trend  toward 
the  use  of  emulsions  in  finishing  work.  Butylated  ureas 
(Plastopols)  were  used  as  primers  for  wood  and  as  a  fin- 
ishing coat  in  conjunction  with  the  adipate.  Alkyd  AT  was 
one  to  one  butylated  urea  with  trimethylolpropane  adipate 
which  baked  at  180°C  (356°F)  or  cured  with  acid.  AW  is 
the  same,  with  a  small  excess  of  adipic  acid.  Both  of  these 
varieties  had  superior  water  resistance.  AT  was  a  similar 
resin  using  hexanetrioladipate  with  butylated  urea  in  one 
to  one  ratio,  curing  at  120°C  (248°F)  with  less  water 
resistance. 

Unusual  success  had  been  obtained  by  use  of  the  poly- 
vinyl  acetate  emulsions  on  wood,  and  Dr.  Jordan  believed 
that  freight  cars  will  go  entirely  to  either  the  urea  systems 
or  polyvinyl  acetates.  The  use  of  polyvinyl  acetate  for 
emulsions  was  held  back  because  of  the  very  large  demands 
for  cementing  leather  scrap  for  shoe  elements. 

Emulsions  of  acrylates  also  did  well  in  tests,  especially 
slight  variations  of  Acronal  500D ;  but  the  cost  was  still 
high  unless  the  new  Reppe  process  for  acrylates  from  acety- 
lene .carbonmonoxide  and  water  in  the  presence  of  nickel 
carbonyl  was  used.  (TO  BE  CONTINUED) 


JULY  1946 


PLASTtCS 


83 


A  JVew  Acrylic 


ANKW  company,  the  Worne  Plastics  Corporation,  has 
just  begun  production  of  acrylic  resins  in  a  plant  at 
Pinewald,  N*.  J..  near  Toms  River.  Utilizing  a  polymeriza- 
tion method  which,  it  is  claimed,  shortens  cure  time  "sub- 
stantially," and,  in  addition,  yields  a  more  uniform  polymer, 
the  company  plans  to  concentrate  on  certain  formulations 
having  different  properties  than  those  of  present  acrylics. 

Initial  production  is  set  at  20,000  Ib  weekly,  of  which 
perhaps  20%  will  be  molding  powder  and  the  balance  cast 
forms — sheets,  rods  and  tubes.  Production  of  48,000  Ib  is 
anticipated  within  three  months,  when  the  proportion  of 
molding  powder  is  to  be  increased  to  50%. 

The  Worne  resins  will  be  available  in  three  series,  desig- 
nated as  WR-50,  WR-60.  and  WR-70.  While  the  first  of 
these  is  similar  to  existing  commercial  formulations,  the 
other  two,  with  which  the  company  is  most  concerned,  are 
said  to  have  superior  values  for  certain  properties.  As  in- 
dicated in  the  accompanying  table  submitted  by  Worne  for 
its  cast  resins,  the  WR-60  and  WR-70  series,  which  have 
high  specific  gravities,  show  greater  values  for  refractive 
index,  heat  distortion  temperature,  surface  hardness  (abra- 
sion resistance)  and  compressive  strength  than  is  shown 
by  the  WR-50  series,  and  lower  water  absorption.  The 
changes  in  properties  of  the  ascending  series  are  indicative 
of  marked  changes  in  the  composition  of  the  material;  in 
fact  the  WR-70  series  is  described  as  thermosetting,  not 
thermoplastic. 

The  WR  resins  are  essentially  copolymers  of  acrylic  acid 
derivatives.  The  monomeric  compounds  are  prepared  from 
acrylonitrile  in  most  cases,  as  shown  in  reaction  No.  1,  be- 
low. The  preparation  of  special  derivatives  is  typified  in 
the  series  of  reactions  No.  2.  First,  ethylene  and  phosgene 
are  reacted  to  form  beta-chloropropionyl  chloride.  This  is 
reacted  with  the  desired  amide,  alcohol,  etc.,  the  resulting 
compound  of  which  is  dehydrohalogenated. 

( 1 )  CH,  —  CHCN  -f  H,SO,  +  CH,OH » 

CH,  =  CHCOOCH,  -f  NH4HSO4 

(2)  CH,  =  CH,  4-  COC1,  — »  CH2CICH,COC1 

CH,C1CH,COC1   4-  C,HSOH »   CH2C1CH, 

COOC,H,  4-  NaOH »  CH,  =  CHCOOC2H» 

4-  NaCl 

The  crude  derivative  is  carefully  purified  by  chemical 
treatment  and  then  subjected  to  fractionation  in  specially 
designed  stills.  As  a  result  of  this  treatment  monomeric 
compounds  of  a  very  high  degree  of  purity  are  obtained. 

The  new  method  of  polymerization,  devised  by  Dr.  How- 
ard E.  Worne,  president  of  the  company,  is  described  by 
him  as  follows:  "Under  controlled  heat,  the  monomeric 
are  subjected  to  the  action  of  a  high  potential  cur- 
rent. This  current,  generated  by  a  specially  developed  piece 
of  apparatus,  tends  to  orient  the  molecule  during  the  course 
of  the  polymerization.  By  close  control  of  the  intensity,  an 
accurate  control  of  the  molecular  weight  is  obtained.  As  a 
result  of  this  action  synthetic  resins  are  obtained  which  are 
superior  in  many  respects.  Electropolymers  have  a  much 
higher  impact  strength  than  polymers  prepared  through 
usual  chemical  methods.  Castings  of  the  clectropolymers 
exhibit  a  greatly  reduced  tendency  to  discoloration  when 
exposed  to  ultraviolet  light." 

In  the  new  process,  the  time  required  for  polymerization 
is  substantially  reduced,  according  to  Dr.  Worne,  who  say* : 
"Highly  purified  monomers  arc  polymerized  in  about  one- 
third  the  time  required  t»  rmnplrtr  the  same  task  through 
the  use  of  chemical  catalysts.  Inasmuch  as  high  potential 


A 

s 

C 

« 

/ 

/ 

r 

/ 

P 

/ 

/ 

X 

1 

/ 

. 

/ 

t 

/ 

> 

/ 

/ 

/ 

/ 

7 

a^L 

t 

/ 

It 

V 

c- 

SolwHo 

n  Polrn 

trrilOtK 

M 

\U 

7 

If, 

V 

f 

0          10          JO        30         »0         50         60         70         80         W         100       110 


High-potential  polymerization  rate  oi  "WR  60'   resin* 

polymerization  does  not  depend  upon  oxygen  in  any  form 
to  perform  its  primary  function,  it  is  a  relatively  simple 
procedure  to  color-match  batches  of  resin.  Organic  dyes 
which  are  affected  by  oxidation  in  most  cases  remain  un- 
affected when  subjected  to  high  potential  polymerization. 
This  allows  the  use  of  desirable  materials  which  heretofore 
could  not  be  used. 

"Through  the  control  made  possible  by  this  IK-U  tm-thod. 
tailored  molecules  are  built  up,  which  vary  in  physical  prop- 
erties over  a  wide  degree.  By  the  careful  selection  of  the 
acrylic  monomers  used  in  these  polymerizations,  WR  resins 
are  obtained  with  the  general  characteristics  listed  in  the 
table." 

With  the  price  of  the  WR-50  series  paralleling  that  of 
available  acrylics,  the  price  of  the  other  series,  whicli  are 
considered  as  special  formulations  made  up  to  meet  partic- 
ular requirements,  range  from  perhaps  $1  to  $2.50  per  Ib. 

Besides  Mr.  Worne,  company  officers  are:  Thomas  Gilles- 
pie.vice  president  ;  and  J.C.  Foster,  secretary-treasurer.  The 
board  of  directors  is  composed  of  the  officers  and  Duncan 
M.  Hair,  Barclay  K.  Read,  Lee  Ritter,  and  O.  J.  Morelock. 
The  plant  manager  is  O.  N.  Piegelbeck,  and  H.  E.  Tegen 
is  manager  of  the  New  York  office.  KND 

Physical  Properties  of  Cast  WR  Resins 


WR-50  Series  WR-60  S.ri.i 


Specific  gravity 1 . 1 8- 1 .20 1 .26- 1 .29 

••tractive  index  n»  .  1 .50- 1 .58 1 .56- 1 .62 

a 

Tentile  Itreng*  (pti). .  8,000- 1  0,000 .  . 
Compreuive  itrcngth 

(p,i) 12,000- 14,000..  13.000- 15,000. 

Elongation  ('  ', ) 1-5 5-1 

Hordn.ii.  Brincll 18-20 25-40 

Heat  dijtortion 

t.mp.  (°  f) 176-185 212-221 

Water  absorption 

(%.24  hre.) 0.4-0.5 05-.07 

Dtelectrk  .tr.ngth  (60 

cycU)  (vcJH  mil.  Vi 

In.,   «hort    tint*)...  500 600 

Di«l«ctric  conitant  (60 

cycle) 3.4-3.6 2.5-2.8 

fewer  factor  (60 

cycle) 01-.03 005-.008 

Machining  quohlin  .  .  Good Good 

Clarity Transparent Transparent 

Color  range 


WR-70  Series 

1.32-1.34 

1.57-1.62 


9,000-1 1,000 7.000-9,000 


.20.000-28.000 

1 .7-2.0 

35-45 


257-270 

08-.1 

550 

..3.0-3.4 


008.. 

fair 

.Trantporenl 
..Unlimited 


84 


PLASTICS 


WHAT'S 


I 


PLASTICS 


Radial-Type  Plunger  Pump 

Superdraulic  Corp. 

1   Dearborn,  Mich. 

Capable  of  constant 

I  or  variable  delivery  of 

I  hydraulic  power  up  to 

I  5000  psi  and  40  hp,  the 
.S'H pfrdraulic    pump 

I  employs  elliptical  reac- 

I  tion  rings  which  give 

I  each  plunger  two  dou- 

!    ble  strokes  per  revolu- 
tion.   Plungers  are  fit- 

|   ted   to  cylinders   in  a 

I   rotor  with  one  or  more 

I   banks   of    11    plungers 

I  per  bank.    Rotor  turns 

I  on  a  fixed  central  pin- 

I  tie  which  has  ducts  and  ports  for  directing  oil  intake  and  de- 

I   livery.     Plungers  are  attached  to  an  equalizing  axle  supporting 

I  two  rollers  approximately  \Yt"  in  dia,  which  ride  on  the  ellip- 

I  tical  rings.     Provision  is  made  for  spring-type  return  means,  to 

I  insure  against  failure  of  the  plungers  to  return  when  pump  is 

|  operated  below  speed  at  which  centrifugal  force  is  adequate. 

Two  banks  of  11  plungers  each  are  arranged  in  a  single  rotor, 
in  variable  delivery  type  of  pump.  Each  pair  of  parallel  cylin- 
ders is  in  open  communication  by  means  of  a  drilled  passage  in 
the  rotor,  and  the  plunger  rollers  of  each  bank  roll  against  sepa- 
rate elliptical  reaction  rings.  By  means  of  integral  bevel-gear 
teeth,  the  two  rings  can  be  rotated  in  opposite  directions. 


Plunger  reaction  loads  exerted  on  the  elliptical  reaction  rings 
are  balanced  through  the  volume  control  gear,  the  torque  of  one 
reaction  ring  balancing  that  of  the  other.  Plunger  tolerances 
are  about  0.0001".  Leakage  is  reduced  to  a  minimum  by  grind- 
ing and  lapping  plungers  and  cylinder  bores (542) 


Dielectric  Heating  Unit 

The  Girdler  Corp.,  Thermex  Div. 
224  E.  Broadway,  Louisville,  Ky. 

Described  as  being  the  first  compact  dielectric  heating  unit 
designed  and  engineered  especially  for  the  plastics  molding 
industry,  the  new  18XO  Thermex  Red  Head  high  frequency 


In  rapidly-moving  times  such  as  these,  keeping  up 
with  every  latest  development  in  one's  field  is  a 
"must."  In  order  to  simplify  for  our  readers  the  task 
of  obtaining  detailed  Information  regarding  the  new 
products,  processes  and  trade  literature  described 
herein,  plastics  has  keyed  each  Item  in  this  section 
with  a  number,  and  has  provided  the  name  and  ad- 
dress of  the  manufacturer  or  producer  of  each. 

Mention  of  the  key  number,  and  of  the  issue  of 
plastics  in  which  the  news  Item  appeared,  will  serve 
as  quick  identification  of  the  product  when  writing 
the  individual  manufacturer  or  producer  for  further 
details. 


AMERICAS  HOLDING  POWER  4  CHEMICAL  CORE 

™ 

E 


AMERICAN  MOLDING  POWDER  AND  CHEMICAL  CORP. 


Manufacturers  of 


MPMCET 


Cellulose  Acetate  Molding  Powders 


Main  office:  44  Hewes  Street 

Brooklyn   11.  N.  Y. 


•  Any  color 

•  Any  flow 


Plant:  67  North  9th  Street 
Brooklyn  11.  N.  Y. 


JULY  1946 


PLASTMCS 


model  has  an  output  of  1  kw,  and  will  raise  the  temp  of  approxi- 
mately 1  Ib  of  average  general  purpose  material  170°  F  in  one 
min 

Molding  cycles  are  shortened,  product  quality  is  enhanced,  and 
the  number  of  rejects  materially  reduced  because  of  its  rapidity 
and  uniformity  in  preheating  preforms.  It  also  lessens  insert 
and  pin  breakage.  Operation  of  this  portable  unit  is  completely 
automatic. 

The  cabinet,  finished  in  heavy  gauge  steel,  is  16!4"  by  27'/4" 
by  52J4".  An  aluminum  plate,  1054"  by  13",  serves  as  the  bottom 
electrode,  while  the  standard  upper  electrode  is  of  stainless  steel 
wire  mesh  7l/3*  by  7!4".  Spacing  between  the  electrodes  is 
adjustable  from  %"  to  1H".  Preforms  up  to  2! j"  in  thickness 
are  accepted  by  the  drawer.  High  frequency  energy  is  turned 
on  by  completely  closing  the  drawer.  This  is  cut  off  when  the 
predetermined  heating  cycle  is  completed i  54.?  i 


guard.    This  new  planer  is  said  to  be  easily  fitted  to  any  drill 
press  in  30  sec 


Drill  Press  Planer 

A.  D.  McBurney 

939  W.  6th  St..  Los  Angela*.  ColU. 


Flying   chips   are   directed   down 


Low  cost,  vibrationless 
operation,  rugged  strength, 
versatility  and  long  work- 
ing life  are  listed  as  out- 
-tanding  qualities  of  the 
new  Safe-T-Planf  tool.  A 
single  blade  with  positive 
cutting  action,  "one-spot" 
blade  adjustment,  a  protec- 
tive hand  and  eye  guard, 
and  exceptionally  light 
weight  are  additional  fea- 
tures. For  precision  work, 
only  one  blade  setting  is 
necessary.  Special  cutters 
are  available  for  work  in 
plastics,  in  metals,  etc. 
by  a  highly  polished  bell 


Rotary  Heat  Sealer 

Pack-Rite  Machines 

714  W.  Wisconsin  Ave.,  Milwaukee  1,  Wis. 

^^__^  —  Thermostatically  cool 
trolled  to  seal  a  wide  range 
i>f  heat  sealing  materials, 
the  l-ast-Titf  is  announced 
as  a  new  development 
which  "answers  the  demand 
for  a  double-drive,  low- 
priced  rotary  heat 
for  bags,  pouches,  etc." 

Pulling  and  di.-turt: 
the    bags    as    they 
through  the  sealing  rollers 

bis  eliminated  by  the  driving 
of  both  sealing  roller  shafts! 
This  model  operates  at  a 

speed  of  300  or  more  lineal  inches  per  min,  depending  on  mate- 
rial being   scaled.     There  is  a  simple  tension   adjustnu  • 
pressure  on  sealing  rollers.    The  Fast-Tile  is  well  constructed; 
and  is  light  weight  and  compact. 

A  preheater  attachment  is  available  for  those  materials  which 
require  preheating  before  entering  the  sealing  rollers (545) 


Injection  Holding  Press 

Hy-Speed  Press  Co..  Inc. 

120  S.  LaSalle  St..  Chicago  3.  111. 

Continuous  cycles,  automatic,  fast,  and  economical  opei 
are  listed  as  features  of  this  2-oz  injection  molding  machine. 

It  is  electrically  heated  and  controlled,  with  air-motor  driven 
oil  pump,  piston  type  rams  throughout,  and  mold  area  12"  l>>  12* 
locked  together  with  hydraulic  locks  to  eliminate  flash. 

Weighing  approximately  2500  Ib,  the  machine  requires  floor 
space  of  only  24"  by  36".  Material  change  is  handled  by  change 


THE  GEE-BEE  MFG.  CO 

ANNOUNCES  THE  REMOVAL  OF  THEIR  PLANT 
TO  LARGER  QUARTERS 


PLASTIC  SLITTING  &  CUTTING  PROBLEMS  SOLVED 


We  slit  all  types  of  plastic  materials  including  cellophane,  acetates,  etc. 

from   1/16  inch  to  75  inches  in  width. 
We  interleave  plastics. 

We  are  equipped  to  slit  up  to  100,000  yds.  per  day. 
Prompt  service. 
Storage  space  available — Equipped  with  railroad  siding. 


Write  to  Us  About  Your  Plastics  Cutting  and  Slitting  Problems 


T.I.  Ev.  7-1331 


76  N.  4th  ST. 


BROOKLYN  11,  N.  Y. 


•I 


I*  I.  \STlt   S 


.11  I.  Y   1916 


Inder,  and  extra  cylinders  are  furnished  with  the  press. 
>pper  holds  25  Ib  of  material,  which  is  fed  automatically 
ation  of  crucible  and  ram (546) 


ft  Electronic  Heater 

Id  Electric  Co..  Industrial  Heating  Div. 

|:  Rd.,  Schenectady  5,  N.  Y. 

A  new  dielectric  heater  for  plastics 
preforms  is  announced  by  its  manu- 
facturer as  featuring  fast  heating, 
simple  operation  and  sturdy  con- 
struction. It  is  designed  for  opera- 
tion at  40  meg,  using  a  water-cooled 
oscillator  tube.  An  average  full- 
power  5  kw  output  during  the  entire 
heating  cycle  is  made  possible  by 
this  tube,  which  operates  at  high 
frequency  and  with  a  short-time 
overload  capacity. 

The  preheating  cycle  is  started  by 
a  push-button,  after  the  plastics  pre- 
forms are  placed  on  the  electrode  of 
the  preheater  and  the  oven  cover  is 
closed.    The  rest  of  the  operation  is 
automatic.   At  the  finish  of  the  heat- 
ing cycle,  the  oven  cover  is  opened 
atically,  and  preforms  are  transferred  to  the  molding  press 
operator (547) 


ite  End  Mill 

elco  Tool  Co.,  Inc. 

omilton  Ave..  Brooklyn  31,  N.  Y. 

lufactured   for  use   on  all   types  of  plastics,   alloy   steel, 

:on,  brass  and  bronze,  the  new  3-flute  end  mill  is  said  to 

reduction  hours  by  its  ability  to  plunge  into  any  plastics 

tal  and  mill  in  the  same  operation. 

ling  is  performed  so  smoothly  that  a  finished  cut  is  hardly 

ed     (548) 


IN  PLASTICS  IT'S 


BOICE- 
CRANE 

POWER  TOOLS 


—available  for  scores  of  machining  and  finishing  operations. 
Designed  for  ready  adaptability  to  a  wide  range  of  projects, 
fewer  machines  are  needed  to  meet  all  your  requirements. 
There  are  band  saws  and  jig  saws  for  straight  and  contour  cut- 
ting, and  equipment  for  drilling,  routing,  tapping,  shaping,  sur- 
face and  end  grinding  '  removing  flash ) ,  surfacing,  polishing, 
etc.  Production-proved.  Safety-engineered.  Shown  is  the  Boice- 
Crane  spindle  shaper. 

Write  for  free  catalog. 


BOICE-CRANE 

911  Central  Ave. 


COMPANY 

Toledo  6,  Ohio 


DRILL    PRESSES 
BAND    SAWS 
JOINTERS        • 


•      JIG    SAWS     •      LATHES 
•          SPINDLE    SHAPERS          • 
THICKNESS    PLANERS        • 


•      BELT    SANDERS 
SAW    JOINTERS 
SPINDLE   SANDERS 


TO  YOUR  SPECIFICATIONS 

For  over  forty  years  we  have  been  leaders  in  the  design 
and  manufacture  of  component  parts  for  leading 
Refrigerator,  Stove,  Furniture,  Appliance  and  Cabinet 
industries.  We  specialize  in  custom  molding  by  the 
injection,  compression  or  transfer  method  in  any  ther- 
mosetting  or  thermoplastic  material.  A  complete  ser- 
vice from  one  source  to  serve  your  needs  —  at  no 
extra  cost. 


RESEARCH  — 

Highly  experienc- 
ed research  engi- 
neers to  deter- 
mine the  material  best  suited 
for  your  needs  as  to  strength, 
utility  and  beauty. 


ENGINEERING— 
Here  is  where  the 
correct  tools,  pre- 
cision dies  and 
molds  are  developed  to  pro- 
duce the  best  job,  efficiently 
and  economically. 


HOLDING   —  A 

complete    depart- 
ment equipped 
•»  with    the    latest 

and  most  modern  presses  and 
molding    equipment   —    *"• 
Injection,     Compression 
Transfer  molding. 


for 
or 


DESIGN  —  A  thor- 
ough study  is  made 
as  to  the  utility, 
shape  and  color  of 
the  plastic  part  that  will  best 
harmonize  with  the  style  and 
design  of  your  product. 


TOOL  AND  MOLD 
MAKING  —  This 
department,  manned 
by  expert  crafts- 
men, makes  the  necessary 
tools  and  molds  to  produce 
the  finished  product. 


INSPECTION 
AND  SHIPPING 

Each  individual 
piece  is  carefully 
inspected  for  uniformity,  col- 
or and  finish.  All  parts  are 
carefully  wrapped  and  packed 
for  utmost  protection. 


//  you  are  planning  the  use  of  plastic  parts  in  your 
products,  it  will  be  advantageous  for  you  to  investi- 
gate our  complete  service.  Write  or  phone  us  about 
your  needs. 


NATIONAL    LOCK 
COMPANY 

Plastics   Division 

ROCKFORD,    ILLINOIS 


Y  1946 


I'LASTtCS 


87 


NEW!     IMPROVED! 


REZ-N-GLUE 

Sticks  everything  to  everything.  Dries  lost 
but  not  too  lost  tor  handling  large  pieces. 
Now  used  extensively  in  such  industries  as 
handbags,  display  fixtures,  decorating,  etc. 

WATER  WHITE 
TRANSPARENT 

A  mild  type  ol  adhesive,  perfect  lor  cementing  mirrors 

to  plastic  without  affecting  either,  also  leather,  cloth  or        === 

wood  to  plastics  or  to  each  other. 

TRIAL  GALLON   *5.5?     F.O.I.  FACTORY 

ORDER!  | 

SCHWARTZ  CHEMICAL  CO.  | 

326-328  West  70  Street,  New  York  23,  N.  Y. 


-RF7-N-KLEEN"    INSTANTLY  ramorn  aU  iaralgn  tub 
.lane.,   from    Lucii.   and    Pl.xiqlai. 

"REZ-N-DYE"    A    «'nql»    lOlution   Cold   Dip    Dy.    to 
Ia»!  color  plastics.  21  Dltt.ronl  Colon. 


WITH  POWERFUL 
PRESSES  THAT 
NEED  NO  POWER 


MODtl   W 


•  It'f  raiy  to  use  FAMCO  Arbor  Presses—  yet  no  power  a  re- 
i)  ii  i  r  i-il.  An  arm  can  deliver  up  to  15  Tons  pressure.  Famco 
"Cost-Cutting"  Machines  are  alio  easy  to  install  and  are  space 
savers.  They're  portable  —  no  power  outlets  needed  —  and  are 
just  the  thing  for  doing  thousands  of  assembly  and  demanding 
job*.  Two  of  the  )2  ruggedly  constructed  bench  and  floor  type 
model*  available  are  illustrated  above.  These  come  in  plain 
lever,  timple  ratchet,  or  combination  compound  and  >imple 
ratchet  types.  Sec  a  Famco  dealer  or  write  today  for  catalog. 

roMco  Pool  PtMMl  lof  light  forming 
and  (tamping  or*  ovoilabl*  in  10  modoli 
(for  bonch  or  floor  *»ownttng|.  lew  in  co»t, 
low 


•III   col  »p  10   II  SOKSO  mild   ilool 
•OM.   o«vrocr  on*  ipood     tuaiodl*  eon 
•Irvctvd  and  a»oiloblo   lit  Rn  liioi. 


FAMCO    MACHINI   CO.,    e      1J2J   Itth    St.    e   RACINI,   WIS. 


fa  mco 
machines 


Literature  Revit 

Laminated  Phenolic  Plastics 

Continental-Diamond  Fibre  Company 
Newark  33.  Delaware 

Covering  the  properties,  manufacture,  and  uses  of  , 
"Catalog  DO  33"  is  designed  to  acquaint  engineers  « 
signers  in  industry  with  this  material. 

An  interesting  and  valuable  feature  of  the  booklet  is 
showing  comparative  electrical  and  mechanical  properties 
Dileclo  sheet  grades 


Dow  Thermoplastics 


Dow  Chemical  Company 
Midland,  Michigan 

Titled    "Plastics    Primer,"    this    attractive    file-size 
covers  properties  and  applications  of  the  various  Dow 
materials.     The  booklet  is  pictorially  illustrated,  and  al 
tains  a  brief  elementary  discussion  on  plastics 

Furfural  and  Derivatives 

The  Quaker  Oats  Co..  Chemicals  Dept. 
141  W.  Jackson  Blvd.,  Chicago  4.  HI. 

Two  16-page  booklets  on  Furfural  and  its  derivatives  i 
available.  Structural  formulae,  nomenclature,  chemical 
ties,  formation  of  compounds,  and  a  description  of  met 
detection  and  analysis,  as  well  as  charts  showing  princ 
actions  of  Furfural,  are  contained  in  Bulletin  202  "Intro 
to  the  Chemistry  of  the  Furans." 

Bulletin  203  titled  "Physical  Data  on  Furfural"  inch 
tables  and  graphs  covering  such  data  as  composition  and  < 
vapor  pressure,  solution  temperatures,  solubility  of  organ 
salts,  gums  and  re-inv 


High-Frequency  Bonding  Machine 

Singer  Sewing  Machine  Company 
149  Broadway,  New  York  6,  N.  Y. 

A  technical  description  of  the  Singer  Electric  Bondt 
chine  Aro.  248-2  is  contained  in  a  6-page  booklet  just  ii 
the  manufacturer.    Resembling  a  modern  high-speed  sew 
chine,  this  unit  accomplishes  seaming  by  the  passage  of 
frequency  electrical  current  through  the  thermopla>tic 
between  two  electrodes,  one  above  and  one  below  the  mat 
be  bonded.     According  to  the  Singer  company,  practica 
thermoplastics  sheet  material  can  be  successfully  bonded 
unit.     Attachments  are  available  for  special  operations 
binding,  hemming  and  half  lap  seam  felling. 

A  discussion  of  the  various  parts  comprising  the  macl 
well   as  a   description   of   its   operating   procedure.   i> 
among  the  data  given  on  this  important  development .... 

Coated  Abrasives 

Behr  Manning  Corp. 
Troy.  New  York 

Said  to  be  the  first  publication  on  the  "sanding"  angle! 
tirv.  this  booklet  titled  "Coated  Abrasives  in  the  Plastic! 
try,"  discusses  abrasive  selection,  machinery  ami  «ju 
buffing,  polishing. 

Prepared  by  the  Kducational  Service  Dept.  of  Behr-II 
Corp.,  the  first  half  of  the  booklet  is  devoted  to  a  simpli 
of  the  various  plastics,  their  names,  characteristics,  mei 
manufacture,  and  uses.    Complete  reference  data  on  70  ril 
plastics  is  included  in  the  center  spread  reference  chart. 
\  -.'-'"  enlargement  <>f  tlii-  chart,  in  three  colors,  acrnin|i; 
booklet 


SOUMINQ   SHEMS     •     AMOR   PRESSES     e     FOOT   PRESSES 


Abrasive  Belt  Grinders 

Hammond  Machinery  Builders,  Inc. 
1600  Douglas  Ave  .  Kalamaxoo  54.  Mich. 

llammmul   Bulletin  .110  introduce*-  the  company'--  thr 
alira-ivr  belt  grinders — l'H-6,  No.  $.  and  /•-'.     Itii 
Mri|>ti»n<   and   detailed   illustrations  of  these  new   mod 
in  the  8-page  file-size  booklet 


PI.  AST  1 1  * 


.III.Y 


PEOPLE 


Boyd  R.  Hopkins  has  been  appointed  eastern  district  man- 
ager of  the  Thermex  Division  of  The  Girdler  Corp. ;  he  is  suc- 
ceeded in  his  former  post  of  central  district  representative  by 
Robert  Smith  Logan,  Jr. 

*  *    * 

John  J.  Townsend  has  joined  Lloyd  Associated,  Inc.,  Phila- 
delphia, where  his  duties  will  be  connected  with  that  organiza- 
tion's newly-formed  low  pressure  section. 

*  *     * 

Product  Designers,  Chicago,  has  announced  the  appointment 
of  Kenneth  P.  Schory  to  the  staff  of  the  organization,  as  an 
executive  designer  in  charge  of  complete  design  assignments. 

*  *     * 

Emory  F.  Smith  has  been  made  sales  manager  for  Koroseal 
and  other  plastics  materials  merchandised  by  International  B.  F. 
Goodrich  Co.,  a  division  of  B.  F.  Goodrich  Co.,  Akron. 


E.  F.  Smith 


G.   P.   Lehmann 


P.  P.  Wojtul 


George  P.  Lehmann  has  been  appointed  to  the  lately-created 
post  of  assistant  manager  of  the  General  Electric  Co.'s  plastics 
divisions. 

*  *     * 

P.  P.  Wojtul  has  become  assistant  to  Hans  A.  Eggerss,  ex- 
ecutive vice  president  of  Continental  Can  Co.,  Inc.  H.  A.  Swert- 
feger  succeeds  Mr.  Wojtul  as  assistant  to  the  vice  president  and 
comptroller. 

*  *     * 

Returned  from  service  in  the  U.  S.  Navy  as  Commander, 
Alfred  Egerter  has  become  assistant  sales  manager  of  the 
Paramet  Corp.,  a  subsidiary  of  Libbey-Owens-Ford  Glass  Co., 
Long  Island  City,  N.  Y. 

*  *     * 

Thomas  Francis  Plummer  has  become  production  manager 
of  International  Plastic  Corp.,  Morristown,  N.  J. 

*  *     * 

Edgar  S.  Thompson  has  joined  the  rubber  and  plastics 
machinery  sales  organization  of  Parrel-Birmingham  Co.,  Inc. 

*  *     * 

R.  Eric  Friden  has  become  a  member  of  the  staff  of  Barnes  & 
Reinecke,  in  the  capacity  of  design  representative. 

*  *     * 

Edwin  L.  Hobson  has  been  named  to  the  sales  staff  of  the 
Plastic  Division  of  Monsanto  Chemical  Co. 

*  *     * 

Advising  that  the  company's  plant  is  being  moved  from  Elk- 
hart  Lake  to  Sheboygan,  Wis.,  Badger  Plastics,  Inc.,  announces 
election  of  the  following  officers :  George  P.  Anderson,  presi- 
dent and  treasurer;  Walter  R.  Cousino,  vice  president; 
Sherrill  W.  Stockton,  secretary  and  superintendent. 

*  *     * 

Appointment  of  N.  B.  Nichols  as  director  of  its  research 
division  has  been  announced  by  Taylor  Instrument  Co. 

*  *     * 

Carl  H.  Pottenger  has  joined  Pennsylvania  Coal  Products 
Co.,  as  vice  president. 

*  *     * 

George  F.  Kahle  has  joined  Heyden  Chemical  Corp.  in  the 
capacity  of  company  representative  in  the  Chicago  area. 


Do  not  accept  substitutes. 
There  is  only  one  flastic 
—CELLO-PLASTIC. 


available  in  many 

beautiful  colors  and 

for  every  purpose. 


Brings  Mew  Colorful  Beauty  and  Durable  Protection  to 
FLOORS  *   WOODWORK*  WALLS  *  EXTERIORS 


Plastic   is   now   prepared   in 
liquid  paint  form  for  use  in 


oils  combined  with  the  finest 

paint  pigments.  ACello- Plastic 

home,office,store,andfactory.  .    ,       . 

This  has  come  about  throueh         Product  is  available  for  almost 

any  type  of  finish  or  surface. 

Does  not  chip  or  crack! 


about  through 

the  formulation  of  synthetic 
resins  withspecially  processed 

BRILLIANT*  SMOOTH*  TOUCH*  DURABLE 

FOR  F I  O  O  R  <*  Cello-Plastic  /transparent/  is  a  non-skid  plastic 
**  .  T fc  ****** ^  finish  for  all  types  of  floors.  Thij  amazing  new 
treatment  gives  floors  a  "cellophane-like"  Plastic  finish.  Eliminates  pores  that 
absorb  dirt,  thus  making  floors  easy  to  clean.  Ideal  for  all  surfaces  including 
wood,  concrete,  linoleum,  asphalt,  tile  rubber,  composition,  etc.  Eliminates 
waxing  ana  polishing.  Unexcelled  for  marine  use. 

EXTERIOR     'rn's  ""odern  finish  is  a  severely  tested  product 
,     that  surpasses  old  fashioned  type  house  paints. 

Figmented  with  Titanium  Dioxide,  the  whitest  and  best  covering  pigment, 
combined  with  kettle  processed  linseed  oils  and  plastic  resins,  it  makes  a  rich, 
colorful,  lasting  coating.  Makes  homes  and  buildings  outstanding.  For  use  on 
wood,  stucco,  brick  or  shingle. 

INTERIOR     Br'n':s  new  glamour  into  homes — protect  floors, 
,  woodwork,   furniture,  etc..  with  its   long-lasting, 

cellophane-like     Plastic  finish.  Easy  to  apply — flows  smoothly— feave*  no 
brush  marks — self  leveling. 

Inquiries  from  Exporters  and  Dealers  Solicited 

Product  liability  underwritten  by  one  of  America's 
largest  insurance  companies. 


CELLO-PLASTIC  CHEMICAL  CO. 

417-419  BLVD.  OF  ALLIES,  PITTSBURGH  19,   PA. 


JULY  1946 


PLASTICS 


89 


SENSATIONAL  PROFITS  FOR 
PLASTICS  FABRICATORS! 


•  litre  i  an  am  wuh  cub  appal  .  .  .  i  sparkling  modern  metal  and 
pl*«ic  cicantu  caic  which  >»u  can  turn  out  in  rour  shop  (or  a>  tow  as 
6*c  MCD.  complete.  The  identical  ciiaraoc  cue  is  scllioc  ai  better  stores 
lac  $2.9). 

•  W«  suppb  the  meul  fUmpincs  .  .  .  You.  the  plastics  fabricator,  make 
the  simple  plastic  cover,  machine  it  to  the  metal  stamping  by  bending  the 
kmr  prongi.  The  local  operation  costs  about  IV. 

•  These  an  the  prices  which  permit  rou  such  a  wide  margin  of  profit; 

Ims:  S4.00  per  d.i.n:   S65  00  pw  gross. 

CV«m.    Plote:    »l  JO    pw    d.l.n.    {93.00    p.- 


.  l-iibtr 
r.  Wt  tmranltt  fan.  rtluhlt  trrtici. 


Sfttih  «*•  •>" 

H  ttUl  SfcfWrfrrf  »r  Ktmg  tat. 

PUct  yf*r  eneVr 


BELLCO  PLASTICS,  INC. 

147  W.  Sidney  Ave..  Mount  Vernon.  N.  Y. 


Specify  MICCROPLATE  Super-finish  ...  the  finest  of 

HRRD  cHRomium 

PLRTinC  FOR  PLRSTIC 
R1010S  RHD  DIES 


MICCKOPIATI  Super-Finish  is  a  new  improved  hard 
chromium  plating  technique  developed  by  specialists  of 
the  Michigan  Chrome  and  Chemical  Company  ...  It 
produces  high-luster  castings  —  eliminates  repolishing, 
c orrot»on.  pitting  and  discoloration  —  prevents  material 
adhesion,  facilitates  material  flow,  reduces  wear  and 
preserves  mold  finish. 

Send  your  mole's  and  diei  for  M/CCBOPlArt  Juper- 
.     All    woHr     guaranteed.     24    HOUR    SERVICE! 


Oiiili»l<  a**  Manx'tx  '>'«/  b  ,  i  HOT  »*< 


MICHIGAN    CHROME    and 
CHEMICAL    COMPANY 

6342  East  Jefferson  Avenue 
Detroit  7,  Michigan 


activities 


Midwest  Chapter  SP(  Holds  Outing 

The  annual  outing  of  the  Midwest  Chapter  of  the  Society  of 
the  Plastics  Industry  was  held  at  Nippersink  Lodge,  Genoa  City. 
\Vis.,  on  June  13  and  14. 

Boating,  swimming,  riding,  and  golf  were  among  the  outdoor 
activities  engaged  in  by  those  attending  the  event. 


SPE  Has  Active  Season 

Organization  of  a  New  York  chapter  of  the  Society  of  Plastics 
Engineers  took  place  at  a  meeting  held  on  May  27  at  the  Hotel 
Commodore.  The  following  directors  were  elected:  For  1  year. 
W.  C.  Peterson,  Ideal  Plastics  Corp.;  C.  E.  Carlson,  Marks 
Products ;  A.  Nufer,  Bakelite  Corp. ;  for  2  years,  David  Murray. 
Boonton  Molding  Co.;  G.  P.  Bohrer,  Ideal  Plastics  Corp.: 
S.  Gurley,  Jr.;  Durez  Plastics  &  Chemicals;  for  3  years,  Robert 
Brinkema,  of  Egmont  Arens ;  C.  Cowan,  Cowan-Boyden  Corp. : 
L.  J.  Francisco,  Formica  Insulation  Co. 

J.  H.  DuBois  conducted  the  meeting  on  behalf  of  the  national 
organization  until  Mr.  Brinkema,  as  temporary  chairman,  took 


Recent  announcement  by  the  St.  Louis  chapter  of  the  Society 
of  Plastics  Engineers  advises  of  the  decision  of  the  St.  Louis 
Plastic  Club  to  disband  and  become  a  part  of  the  first-named 
organization. 

*  »     » 

Meeting  at  the  Merchants  &  Manufacturers  Club  on  June  4, 
the  Chicago  section  of  the  Society  of  Plastics  Engineers  heard 
illustrated  talks  by  W.  C.  Goggin,  manager  of  the  plastics  de- 
velopment division,  Dow  Chemical  Co.,  and  E.  F.  Borro,  devel- 
opment engineer,  Durez  Plastics  &  Chemicals,  Inc.,  featured 
speakers  of  the  evening. 

Mr.  Goggin's  address  dealt  with  the  subject  of  plastics  fabrica- 
tion in  Germany,  where  he  gathered  first-hand  information  as  a 
member  of  the  plastics  team  sent  by  the  U.  S.  Quartermaster 
Corps  to  study  the  plastics  industry  in  that  country,  in  the  sum- 
mer of  1945.  Mr.  Borro's  speech  was  titled  "Measuring  Flow 
of  Thcrmosetting  Plastics." 

Announcement  was  made  by  Wm.  B.  Hoey  that  the  3rd  An- 
nual Exhibit  sponsored  by  the  SPE  is  scheduled  for  the  week 
of  January  27,  1947,  at  the  Coliseum,  in  Chicago.  He  also  stated 
that  the  Chicago  section  of  the  organization  now  has  the  largest 
SPE  section  membership. 

The  Chicago  section  plans  to  hold  a  golf  meet  at  the  Elmhurst 
Country  Club,  on  August  16,  according  to  further  announcement 
made  at  the  June  meeting. 

*  •    • 

At  its  meeting  on  May  24.  the  Cleveland  section  of  the 
Society  of  Plastics  Engineers  heard  a  talk  by  Jack  Morrison, 
an  official  of  the  Detroit  Mold  Engineering  Co..  on  the  evolution 
and  development  of  the  standard  mold  !>.• 


Plans  for  the  June  28  meeting  of  the  Detroit  Section  of  tlir 
Society  of  Plastics  Engineer*  included  a  talk  by  B.  H.  Hertz- 
Guardian  Glass  Co.,  featured  as  after-dinner  speaker. 
Hi-  topi,  was  scheduled  as  "The  Role  of  Plastics  in  Safety 
Glass." 

The  July  12  meeting  is  to  be  held  as  a  golf  tournament  at  the 
i.lrn  Oaks  Golf  and  Country  Club,  and  a  Rolf  tournament  is 
also  planned  for  the  Section's  August  16  meeting. 


N 


f»I.  ISTI.   s 


Jl'LY   1946 


PROBLEMS  ill 


plastics 


Problems  and  que»Hons  may  be  submitted  to 
rhti  department  {or  answering  by  the  techni- 
cal editors  or  f  p  e  e  !  a  I  i  s  t  s  In  the  Industry. 


We  have  received  orders  for  plastics  film  in  narrower  widths 
than  we  produce.  As  we  do  not  have  the  facilities  for  cutting 
them,  can  you  refer  us  to  somebody  who  can  handle  this  for  us 
on  a  sub-contractual  basis,  and  who  will  prepare  the  film  for 
safe  handling  during  shipment  ?  G.  J.  F.,  New  York,  N.  Y. 

The  Cee-Bee  Manufacturing  Company,  76  N.  4th  St.,  Brook- 
lyn, is  equipped  for  this  type  of  service.  Besides  slitting  the  film, 
they  interleave  it  with  paper  to  prevent  sticking  during  shipment. 


Our  client  is  a  manufacturer  of  blocks  which  take  the  place 
of  building  blocks  and  insulation  for  deep  freezers.  He  wants 
a  hard  glaze  surface  on  his  blocks,  or  a  hard  surfaced  shell  into 
which  the  mixture  can  be  poured.  This  shell  will  be  the  surface 
of  the  block  when  it  sets,  such  surface  to  withstand  all  weather 
conditions. 

What  our  client  had  in  mind  was  a  liquid  plastics  that  could 
be  mixed  with  cement.  Is  this  possible,  economical? 

H.  C.  A.,  Mankato,  Minn. 

It  is  possible,  but  not  economical.  We  suggest  you  get  in  touch 
with  the  following  companies  who  may  be  able  to  help  you: 
'American  Cyanamid  Co.,  Plastics  Div.,  30  Rockefeller  Plaza, 
New  York;  Plaskon  Div.,  Libbey-Owens-Ford  Glass  Co.,  2112 
Sylvan  Ave.,  Toledo,  Ohio;  Monsanto  Chemical  Co.,  Plastics 
n\v.,  Springfield  2,  Mass. 


Can  you  tell  us  where  we  may  obtain  technical  information  on 
preparing  plastics  blanks  which  we  may  grind  and  polish  into 
7"  dia.  mirrors,  unpierced  in  the  center. 

Our  present  methods  of  grinding  are  those  applicable  to  glass 
optical  element  fabrication,  and  we  shall  have  to  work  out  modi- 
fications for  the  finishing  of  plastics  surfaces. 

I.  G.  M.,  Brooklyn,  N.  Y. 

We  suggest  that  you  contact  the  Polaroid  Corp.,  Cambridge, 
Mass..  which  carried  on  most  of  the  development  ivork  in  this 
field  for  the  government. 


What  are  the  advantages  of  plastics-impregnated  plaster  of 
Paris  ?  M.  C.  C.,  Boston,  Mass. 

Increased  impact  strength,  improved  surface  hardness,  greater 
resistance  to  abrasion,  are  among  the  principal  values. 


Is  it  possible  to  use  the  blanking  method  in  the  fabrication  of 
articles  from  acrylic  sheets?  A.  B.  F.,  Chicago,  111. 

Blanking  has  been  used  in  the  fabrication  of  articles  from 
cellulose  acetate  and  cellulose  nitrate  for  a  long  time.  More 
recently,  this  method  has  been  adapted  to  the  manufacture  of 
items  from  acrylic  sheets,  although  the  operation  requires  greater 
skill  than  is  needed  for  the  cellulosics.  Generally,  the  acrylics 
must  be  blanked  at  a  temperature  of  not  less  than  250°  F ;  and 
for  heavy  gauges,  300°  F  is  often  desirable. 


Working 
Sample 
Free 


Request  Your  Free  Samples 

We  gladly  furnish  working  samples  of  Rayco  Fillers. 
What  is  more,  we  gladly  furnish  the  research  service 
to  fit  our  fillers  to  your  needs  EXACTLY.  This  is  most 
important.  As  pioneers  in  cotton  fillers,  we  know  that 
small  modifications  in  type  and  length  often  lead  to 
big  improvements  in  the  desired  characteristics  of 
i  tensile,  impact  and  flexural  strength.  So — you're  en- 
titled to  samples  of  our  Fillers,  and  of  our  "Research- 
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RAYON  PROCESSING  CO. 

45    TREMONT    ST.,  CENTRAL    FALLS,  RHODE    ISLAND 


of  R.I. 

INC. 


Gotten.  QilUn*  {a* 


JULY  1946 


I'l.ASTiCS 


9t 


MANUFACTURERS 
ATTENTION! 


National  Distributors  and  Manufacturers  Rep- 
resentatives Catering  in  Large  Volume  to: 

JOBBERS  CHAINS 

Drug  -  Jewelry  -  Tobacco          Drug  -  Variety 
Notion  -  Premium  -  Novelties     Auto  Accessory 

We  are  in  a  position  to  sell  entire  mould  ca- 
pacity of  your  product  We  finance  our  own 
accounts  and  give  close  co-operation  on  styling, 
advertising,  display  and  merchandising. 

CHARLES  H.  FISCHBERG  t  Co.,  LTD. 

Address:  Home  Office: 
71  West  23rd  St.  New  York  10.  N.  Y. 

Representatives   in: 
Chicago  •  St.  Louis  -  Dallas  •  lot  Angeles  •  Miami 


IN  GOLD,  SILVER  OR  COLORS 


Stationery  Design 

(Continued  from  page  24) 


when  the  bindings  are  deformed  by  blows  during  shipping. 
Wire,  of  course,  will  retain  the  deformation. 

However,  another  firm  manufacturing  plastics  binding 
has  expressed  dissatisfaction  with  the  thrust  resistance  of 
plastics  used  for  coil  bindings  and,  if  improvement  is  not 
forthcoming,  it  intends  to  return  to  metal  wire.  Leaving 
the  door  open  for  plastics,  the  company  believes  that  the 
quality  of  the  plastics  can  be  improved  so  as  to  obviate  this 
disadvantage.  Part  of  the  difficulty  is  attributed  to  the 
non-uniform  quality  of  the  extruded  plastics,  for  which  it 
holds  the  extruders  responsible.  To  insure  uniformity  and 
high  quality  it  proposes  that  the  materials  manufacturers 
themselves  supervise  the  subsequent  extrusion  operations. 

Cellulose  Acetate  Widely  Used 

Cellulose  acetate  is  widely  used  in  stationery  equipment 
for  wastepaper  baskets,  stapler  handles  and  bases,  letter 
openers,  pencil  ferrules,  and  miscellaneous  desk  supplies, 
such  as  memo  pad  holders,  calendars,  and  desk  pads.  The  cel- 
lulose acetate  keys  of  some  typewriters  as  well  as  of  the 
comptometer,  an  adding  machine,  are  made  of  Lumarilh  and 
are  easy  to  clean,  pleasant  to  the  touch,  and  economical  to 
make.  Lumarith  is  also  used  as  the  covers  of  engagement  and 
memo  hooks.  Lord  &  Taylor,  New  York  City,  retails  these 
books — diaries,  shopping  lists,  menus,  etc. — for  $1.00  each. 

The  Hydrmvlik  moistener,  by  now  a  very  familiar  mailing 
room  device  made  with  either  a  cellulose  nitrate  or  cellulose 
aceto-butyrate  reservoir,  is  available  in  either  red,  blue,  or 
green.  It  is.  the  makers  assert,  the  most  efficient  moistener 
for  letter  flaps,  seals,  tapes,  stamps,  labels,  etc.,  used  today. 
With  one  simple  motion  it  produces  an  even  ribbon-like 
strip  of  moisture  which  is  sucked  back,  if  not  used  up,  into 
the  cylindrical  reservoir  by  a  valve  arrangement.  When  in 
use,  water  is  supplied  automatically  to  the  sponge  rubber 
>prea<ler.  This  useful  device  retails  for  15c. 

The  use  of  plastics  in  lead  pencils  is  subject  to  several 
conditions.  According  to  the  American  Pencil  Co.,  which 
for  the  past  few  years  has  been  making  pencils  with  l>oth 


Field  Manufacturing  Co.  molds  phenolic  cutter  holder 

PLASTIC*  JULY  1946 


ite  and  butyrate  ferrules,  plastics  will  likely  be  replaced 
ictal  for  this  use.  It  gives  two  reasons.  First,  plastics 
ales  have  to  be  installed  by  hand,  whereas  metal  ones 
be  installed  with  automatic  machinery.  However,  there 
>  reason  why  automatic  machines  cannot  be  developed 
'abricating  plastics  in  ferrules.  Second,  plastics  ferrules 
associated  in  the  public  mind  with  the  poorest  type  of 
;rs,  and  the  company  argues  that  the  consumer  will  not 
inue  to  buy  a  product  which  is  identified  as  a  war-time 
titute. 

espite  its  tentative  decision  to  discontinue  using  plastics, 
.ompany  affirms  that  plastics  ferrules  in  themselves  have 
quite  satisfactory.  Their  agreeable  feel  and  high  tone 
rs  have  pleased  the  consumer.  Perhaps  this  company  is 
ng  up  too  easily.  What  it  might  do  is  make  clear  to 
consumer  by  advertising  and  promotion  the  virtues  of 
ics,  stressing  the  facts  that  plastics  are  by  no  means  a 
titute  material  and  that  their  use  in  conjunction  with 
ctive  erasers  was  only  a  war-time  measure, 
nother  pencil  manufacturer  with  a  similar  policy  toward 
tics  is  the  Eberhard  Faber  Co.,  whose  Mongol  866  col- 
I  indelible  pencil  is  made  with  a  cellulose  acetate  cap 
le  eraser  end.  An  indelible  pencil  needs  no  eraser  and 
:e  plastics  may  be  thought  of  as  an  eminently  suitable 
erial  to  brighten  the  pencil.  Nevertheless,  although  this 
i  is  quite  satisfied  in  some  respects  with  the  plastics  cap, 
itends  to  return  to  metal,  its  reason  being  that  "metal 
:s  better."  This  point  of  view  is  at  variance  with  the 
re  of  most  manufacturers  of  plastics  products,  who  be- 
e  that  one  of  the  chief  virtues  of  plastics  is  their  color- 
ity.  At  the  heart  of  the  matter  may  be  an  unwillingness 
mck  the  consumers'  traditional  preferences.  Here  also 
iducational  campaign  may  be  in  order.  However,  the  use 


of  plastics,  particularly  cellulose  nitrate,  for  barrels  and  caps 
of  automatic  pens  and  pencils  is  unchallenged. 

The  Union  Pencil  Co.,  New  York  City,  manufactures  a 
line  of  stationery  articles  in  which  plastics  are  regarded  as 
fitting  the  bill  perfectly.  This  company  has  very  willingly 
embraced  plastics  and  is  experimenting  now  with  new 
designs  and  new  articles  incorporating  plastics  parts.  At 
present  it  makes  a  polystyrene  letter  opener,  retailing  at 
29c,  which  is  available  both  transparent  and  colored.  Its 
light  weight,  pleasant  feel,  and  brilliant  appearance  make  it 
a  very  fast-moving  article.  Another  of  the  company's  prod- 
ucts is  a  4  by  6  Tenite  II  memo  sheet  holder  in  mottled 
brown  as  well  as  in  pastel  shades.  This  retails  at  $1.24 
and  is  selling  as  rapidly  as  it  can  be  produced.  (Other  com- 
panies use  phenolic  and  cellulose  acetate  molding  powders 
for  making  holders  of  this  type.)  Completing  its  plastics 
lines  is  a  pen  and  funnel  base  unit.  The  pen,  which  is  capa- 
ble of  writing  200  words  with  one  dip,  has  a  Tenite  II 
funnel,  barrel  and  taper ;  the  base  is  referred  to  as  a  cold- 
molded  plastics,  containing  a  mixture  of  sawdust,  a  mag- 
nesium compound,  salt,  water  and  pigments.  The  combi- 
nation retails  for  $1.25. 

Phenofics  for  Stationery  Products 

The  Frank  A.  Weeks  Manufacturing  Co.  is  still  another 
stationery  firm  incorporating  plastics  into  its  products. 
Using  phenolic  molding  material,  it  makes  a  rocker  blotter 
injection  molded  in  two  parts  and  an  inkwell  housing  with 
a  sliding  lid.  Both  articles  are  light,  useful  tools;  they 
retail  for  about  $1.50  each.  A  200-year  calendar,  with 
phenolic  housing  supplied  in  either  a  walnut  or  mahogany 
finish,  is  another  plastics  item  made  by  this  firm.  The  new 
calendar  not  only  has  the  advantage  of  indicating  any  past 


The  K  &  J  organization  ...  to  a  man  .  .  . 
takes  a  personal  interest  in  every  molding 
problem. 


K  &  J  REPRESENTATIVES 

can  help  you  any  time  you  need  advice  on  the 
subject  of  RIGHT  molding.  And  these  boys 
have  the  answer  to  "what  molding  material 
and  method."  Write  or  phone  the  K  &  J 
representative  nearest  you  ...  his  suggestions 
incur  no  obligation  on  your  part. 


TRADE    MARK 


KUHO  &  JflCOB  mOLDIM  &  TOOL  CO. 


1200  SOUTHARD  STREET.  TRENTON  8.  N.  J. 

TELEPHONE  TRENTON  5391 


Sales  Representatives:  NEW  YORK — S.  C.  Ullman,  33  W.  42nd  St.      PHILADELPHIA — Towle  &  Son  Co.,  1  8  W.  Chelton  Ave.  Bldg. 

NEW  ENGLAND— Wm.  T.  Wyler,  177  State  St.,  Bridgeport,  Conn. 


LY    1946 


PLASTICS 


93 


•  Certain  plastics  withstand  heat 
better  than  others.  Some  are  particu- 
larly adapted  for  jobs  thai  must  with- 
stand wear.  Others  are  best  for  ma- 
chining and  threading.  •  The  secret 
V  of  success  in  plastics  is  in  knowing 

V  the  right  plastic  to  use  for  the  job  al 

\         hand.  •  Ask  us  to  help  you  see  what 
\       plastics  can  do  in  your  business. 

• ->X       •  Just  send  photo,  sample  or  specifi- 

>v    cations,  and  we'll  tell  you  quickly  if 
\  it  can  be  made  in  moulded  plastics. 


THE  MAGNETIC  PLASTICS  CO. 

1900   IUCLID    BUILDING      •      CLEVELAND   15,   OHIO 


ADJUSTABLE  FLY  CUTTER 

Two  models  cut  quick,  clean,  accurate  holes  within  • 
2VS"  to  10"  range,  up  to  1"  thick.  Cross-section  of  cut 
has  appearance  of  letter  "W"  with  each  blade  taking 
out  its  own  tide.  Unique  angles  at  which  blades  are 
held  and  new  grinding  technique  on  high-speed  steel 
cutting  blades  assures  smooth  clean  cuts.  Shank  is 
heat-treated.  Removable  pilot,  hardened  and  ground, 
permits  use  of  lead  drilli. 

for  tomptflt  information,  coll  your  Clark  Cutttr  Jobbtr 
ladof  or  wnt»  lor  tololog  i  7  H. 


or  future  date  in  the  19th  and  20th  centuries,  but 
can  be  used  a-  a  monthly  calendar.     This  Kxecutiv* 
Calendar  retails  at  about  $15. 

For  the  home  and  for  office  stockrooms  and  mailing 
the  Safeway  Carton  Cutter,  a  phenolic  molded  prod 
Field  Manufacturing  Co.,  Inc..  New  York  City 
tool  for  opening  cartons  and  cutting  corrugated  paj* 
fibre  board  to  special  sizes.  This  cutter,  retailing  at 
may  be  used  to  open  cartons  quickly,  without  danger 
contents,  from  either  the  side  or  the  top.  A  razor 
which  fits  between  the  two  halves  of  the  cutter  is  the  c 
tool.  The  cutter  fits  comfortably  in  the  palm  01  tin 
and  has  only  one  screw,  by  which  all  adjustments  < 
made. 

Staplers  of  "Tenite" 

Here  is  a  product  in  which  plastics  serve  as  satisi 
and  as  not  so  satisfactory  components — the  common 
stapler.  One  type  of  stapler  has  a  Tenite  11  knob,  on 
the  hand  rests  during  the  stapling  operation,  and  a  Tet 
base,  the  part  which  receives  the  impact.  Now,  the  p 
knob  is  serviceable  in  all  respects  and  will  be  re( 
However,  it  is  reported  that  the  base,  which  i 
full  force  of  the  blow,  works  out  of  alignment  after  .- 
Still,  the  company  has  no  objection  to  the  use  of  plas 
this  defect  could  be  corrected.  Officials  point  out 
change  of  design  or  perhaps  a  change  of  material  may 
come  it,  and  with  this  end  in  mind  they  are  experimi 
at  present. 

Another  stapler  manufacturer,  the  Hotchkiss  Sale 
Connecticut,  makes  a  stapler  No.  220A  with  a  ph« 
molded  cap  and  base  at  a  recommended  retail  price  of 
The  frame  is  made  of  welded  steel,  and  all  working 
are  fully  hardened.  A  single  simple  operation  separal 
head  from  the  base,  so  that  the  stapler  can  then  be  u-e 
lacker. 

Comprehensive  as  this  survey  is,  it  does  not  prett 
cover  every  item  in  this  wide-ranging  field  of  producl 
new  plastics  applications  are  made  in  it  constantly. 


Admiral  Uses  More  Plastics 

i  Continued  from  page  SO) 


•JM  SANTA  MONICA  IOUUVARD     •     KVfRlV  HIUS   CALIFORNIA 


94 


lively  in  a  nine  cubic  foot  size  approximately  11.  _': 
31  oz  of  polystyrene,  and  \\Yi,  15,  and  \3'/2  Ib  <>i  f 
based  phenolic  laminates.  Also  the  De  Luxe  and  the 
Temp  use  3J4  and  6J4  oz  of  acrylics,  and  ihe  l>nal- 
uses  an  ounce  of  phenolics  besides  that  which  is  used  i 
laminates. 

The  three  models  have  the  following  part.-*  in  enm 
cold  compartment  door  or  doors,  of  polystyrene,  mold 
Chicago  Molded  Products  Corp.  for  the  Dual- 1  cm/ 
by  Standard  Products  Co.  for  the  other  two  models ;  l>r< 
frame  and  door  pan,  molded  of  paper-based  laminate  b 
Capac  Manufacturing  Co.:  and  cold  control  knoli-  .m 
cutcheons,  all  of  polystyrene,  molded  by  Standard  Pro 
Co.  for  the  Dual-Temp  and  by  Superior  Plastic  Go.  in 
other  models.  The  Dual-Temp  is  divided  into  two  sec 
— a  cold  compartment  or  freezing  locker  above,  with 
peratures  ranging  to  15°  below  zero  and  with  u|>  to 
capacity,  and  a  moist  cold  compartment  below,  l-.nt 
gained  to  the  upper  section  through  a  set  nf  transp, 
|M,lystyrene  inner  doors.  The  Iro/en  storage  locker  il 
/'.-  /  ii.rr  is  a  full-width  plate  tyjie  with  a  single  wide  < 
hinge  type  door.  The  Master  has  about  a  half  width 
storage  compartment  with  a  single  white  polystyrene 
c'lx-ratmj;  mi  a  side-v\\  inging  hinge. 

!:•  -ides   the   parts  eommoii   to  all   three   models,  tin 
/:<!,    and   the    Dual-temp  have   (xilystyrene   vegetable 


JULY 


drator  fronts,  molded  by  Standard  Products  Co.,  and  name- 
plates  and  trim,  of  acrylics,  molded  by  Hoosier  Cardinal 
Corp.  In  addition,  the  De  Luxe  contains  a  paper-phenolic 
laminated  storage  tray  (made  by  Capac  Manufacturing 
Co.),  insulated  on  sidewalls  and  bottom  by  YI"  of  mineral 
wool;  a  Capac  frame  to  hold  the  bottom  plate  in  the- cold 
compartment ;  and,  along  with  the  Master,  laminated  corner 
support  brackets. 

Although  the  Dual-Temp  does  not  have  these  two  lami- 
nated parts,  it  has  a  number  of  plastics  parts  not  possessed 
by  either  of  the  other  two  models,  including  a  laminated 
divider  support  strip;  chrome-plated  phenolic  handles  on 
the  double  doors  to  the  freezing  or  cold  compartment;  a 
polystyrene  drip  tray  front;  and  a  plastics  shelf  stud.  Ac- 
cess to  the  cold  compartment  is  possible  by  either  of  the 
double  doors,  thus  allowing  less  cold  air  to  escape  than  if 
one  large  single  door  were  used. 

Of  special  interest  in  all  three  models  is  the  paper-lami- 
nated breaker  frame.  Pressed  from  a  laminated  sheet  into 
the  desired  shape  over  steam-heated  dies,  the  one-piece  part 
is  said  by  Admiral  engineers  to  replace  over  20  parts  used 
to  do  the  same  job  in  previous  models.  Among  its  advan- 
tages, the  new  part  does  away  with  the  need  for  a  breaker 
strip.  Also,  whereas  the  conventional  breaker  frame  merely 
covered  the  opening  of  the  insulation  compartment  without 
sealing  it,  in  the  Dual-Temp  the  new-type  frame  hermeti- 
cally seals  the  opening. 

Refrigerators 

In  their  use  of  plastics  in  refrigerators,  Admiral  engi- 
neers regard  polystyrene  as  a  decorative  rather  than  a  func- 
tional material,  and  try  to  avoid  its  use  under  strain  because 
of  the  danger  of  cold  flow.  Likewise,  it  is  not  used  where 
there  is  too  much  risk  of  sudden  and  heavy  shock.  Its  only 
functional  or  semi-functional  use  in  the  Dual-Temp  is  in 
the  cold  compartment  doors,  and  there  tests  have  proved  it 
more  than  adequate  for  the  use. 


Eight  control  switches,  four  handles,  and  the  push  buttons 
(not  indicated)  on  the  automatic  timer  make  up  the  plastics 
parts  on  the  new-model  range.  The  handles  have  metal  grips 
which  are  clinched  on  in  holes  provided  for  that  purpose 


FOR   FABRICS  WITH 
A   PROMISING    FUTURE 

SARAN  monofilaments  are  weaving  new  beauty 
and  durability  into  today's  textiles.  In  brilliant 
colors  and  delicate  pastels,  SARAN  fabrics  are 
sunfast.  They  resist  dirt  and  chemicals  —  a  damp 
cloth  keeps  them  bright  and  sparkling.  For  up- 
holstery, auto  seating,  shoes,  luggage,  handbags 
—  SARAN  holds  a  promising  future- 


NATIONAL  does  no  fabricating,  but  our 
skilled  technical  services  are  available  for  the 
study  of  your  product.  Write  today. 


OOCNTON.   MARYLAND  ' 


BENZOYL 


PEROXIDE 


JULY  1946 


PLASTICS 


95 


IF  YOU  WANT  OUTLETS 
CONTACT  US 

Anything    pertaining    to    Smoker*    Articles 
or   General    Merchandising   and    Novelties 

*  *     * 

We  Contact  Jobbers  and  Chain  Store  and 
Department  Stores  from  Coast  to  Coast! 

(V*  Wm  C-rry  Omr  Ow~   4~.-f.li  I/  N rj  ) 

*  *       * 

M.  B.  SIEGEL 

AfSOCIATIS 
FACTORY    RIFtlStNTATIVIS    AND     DIST«IIUTO«S 

43  E.  ADAMS  ST.  CHICAftO  3.  ILL. 


NOW  AVAILABLE 

Special  Edition  of 

Industrial  Materials 


I  p«g»i.  diieu»iing  procedure!,  techniques, 
ch«rectemtic»  of  Ethoc.l  PG  and  75S 
Aluminum  Alloy  

Send  25c  In  cosh  to 


25' 


ZIFF-DAVIS  PUBLISHING  COMPANY 

Dept.    I.N.D..    Circulation 
18S   N.   Wobaih   Ave.,   Chicago   1.   III. 


DISPLAY  EXECUTIVE  WANTED 

A  famous  Mid-Western  department  (tore  need*  a  man. 
This  man  should  have  some  architectural  background, 
a  flair  for  design  and  exceptional  color  sense,  and  the 
•Ive  ability  to  head  up  a  large  Interior  and  window- 
display  operation.  He  would  be  expected  to  raise  the 
color,  decorative  and  design  taste  levels  of  the  operation 
to  the  hlKhest  plane.  He  would  also  serve  as  consultant 
on  color  changes  and  use  In  our  complete  store  Interior. 
If  this  Is  you,  a  very  Important  and  financially  attrac- 
tive Job  Is  here  for  you. 

Writ*   Boi   92.  c  o  Plo.tici. 
IIS  N.  Wabath  Ave.  Chicago  1,  III. 


FOR  SALE- 


New  •  U«td  Hydraulic  Equipment.     Con«ult«nt,  Engineering 
end   Ptepeir  Service.     Send   us  your  Inquiries 

AARON  MACHINERY  CO. 

4S   Croiby   M..  N.   T.  C.    13  T.I.    Cwol   14421 


INJECTION    MOLDING! 

Open   Capacity   for   Smell    Itemt 

Toyt— Noveltiet,   Omcmentt.   etc..   Any   Quantity 

Low  Mold  Cott. 

PLASTIC   PRODUCTS  CO. 

PkMM   Co  .to.   4-7444 
211    7H  S.I.,    CANTON.   OHIO 


GRADUATE    MECHANICAL    ENGINEER 

Fie*ll«flt  •  pportunlty  •  flared  !•  ambitf*ut  and  pr«gre««lvf  younf 
•a*  vfe*  d*«lrw  It  l«arn  all  pba%t*  »f  plastic  tn«lnvtrlnt  f»r  hi* 
fHtvn  prcftttfon 

Pltatt    «•••'>    cvmpUtt    backiraund    of    «  due  a  tit*,    training    ai- 
p*rl«*>e«  '•  a   l*tltr   Uday 

RATHBUN  MOLDING  CORPORATION 

SALAMANCA.    NIW    VONK 


Polystyrene  was  chosen  for  the  di>ors  because  of  light 
weight,  transparency.  resistance  to  moisture,  dimensional 
stability,  and  its  ability  to  maintain  these  characteristic-,  at 
temperatures  well  Ix-lmv  free/ing.  After  a  trial  run  of 
doors  had  been  molded  by  the  Chicago  Molded  Products 
Corp.,  rigid  tests  were  set  up  to  determine  their  ruggedness 
and  endurance  under  the  opening  and  closing  they  would 
encounter  in  actual  ti~e. 

The  design  of  the  refrigerator  requires  that  the  doors  be 
held  closed  by  a  spring  of  two-ounce  tension.  so  that  they 
snap  shut  when  released.  For  the  test,  the  door  wa- 
mounted  on  a  hinge  of  25%  greater  pressure  in  order  to 
insure  an  adequate  margin  of  safety.  A  mechanism  was 
set  up  which  opened  the  door  and  then  released  it  to  slam 
shut,  all  at  the  rate  of  22  operations  per  minute. 

After  85,000  slams  at  room  temperature,  no  signs  of 
fracture  appeared.  Since  experience  shows  that  such  doors 
are  operated  from  10  to  15  time*  a  day  in  the  average  home. 
this  test  was  the  equivalent  of  more  than  15  years  of  con- 
tinuous service,  whereas  10  years'  service  life  is  usually 
established  as  the  criterion  in  making  accelerated  tests. 

Next,  the  testing  mechanism  was  set  up  in  one  of  Ad- 
miral's "stratosphere  chambers."  where  the  temperature 
was  maintained  Ix-tween  5°  above  zero  and  10°  below. 
Again  the  door  was  slammed  hour  after  hour,  and  at  the 
end  of  50,000  slams,  there  was  again  no  evidence  of  fracture. 

The  laminates  slated  to  become  component  parts  of  Ad- 
miral refrigerators  also  must  meet  certain  requirements' 
involving;  moisture  absorption,  indict  strength,  odor  pickup, 
finish,  and  operation  in  hot  and  cold  cycles.  Moisture  ab- 
sorption in  the  laminates  is  not  a  disadvantage  except  that 
it  sometimes  leads  to  undesirable  dimensional  changes.  A 
means  to  prevent  this  unwanted  distortion  at  Admiral  is  to 
use  a  larger,  stiffer.  and  stronger  laminated  piece  than  re- 
quired functionally  to  do  the  given  job.  Because  the  result 
is  added  luilk  and  weight,  this  method  is  regarded  as  less 
desirable  than  that  of  designing  for  dimensional  change. 
For  example,  a  panel  is  bowed  wherever  it  can  be;  then 
when  moisture  is  alisorlied.  the  resulting  expansion  will  be 
taken  up  by  an  increase  in  the  bow  and  no  damage  will 
be  caused.  This  principle  is  used  in  the  design  and  manu- 
facture of  the  door  pan. 

Odor  retention  of  materials  used  in  refrigerator  manu- 
facture must  !«•  guarded  against.  The  laminates  are  given 
a  butter  test,  a  chunk  of  butter  and  a  piece  of  the  laminate 
being  put  into  a  covered  dish  and  stored  in  a  warm  place. 
After  a  specified  time,  the  cover  of  the  dish  is  removed,  the 
laminate  isolated  from  the  butter,  and  the  nose  called  on 
.1-  the  device  to  test  for  odor  retention. 

In  testing  impact  strength,  a  liall -dropping  test  on  a  small 
sheet  of  the  laminate  is  used.  As  no  standard  has  been 
formulated,  the  test  gives  comparative  results  only. 

Plastics  parts  receive  incidental  tests  as  the  various  ma- 
jor elements  of  the  refrigerators  undergo  an  assortment 
of  trials. 

Kitchen  Ranges 

Plastics  have  not  proved  themselves  as  far  as  heat  is 
concerned,  say  Admiral  engineer*,  but  have  U-en  used 
wherever  (mssihlc  in  the  manufacture  of  electric  ranges. 
The  new  models,  which  represent  great  concession"  to 
the  trend  at  Admiral  and  to  the  enthusiasm  for  plastics  in 
other  departments,  notably  refrigeration,  will  have  white 
I'laskoii  urea  formaldehyde  handles,  control  ^witches,  and 
push  buttons  on  the  automatic  timer. 

In  its  extensive  consumer  advertising — in  folders,  m 
news|Ki|H'rs,  in  approximately  a  do/en  coiisiuner  magazines, 
and  by  radio— Admiral  advertises  plastics  in  connection 
with  radios  but  not  with  reft  igerator*  ami  ranges.  The 
•  plastics  part*  in  refrigerators  is  not  .tressed  liecause 
of  the  involved  technical  explanation  that  would  almost  tie 


N 


JULY  ISIfi 


idntory.  Radio  advertising,  on  the  other  hand,  makes  a 
cial  point  of  "smart  plastics  cabinets  in  a  choice  of  ivory 
mahogany  finish"  and  of  a  "modern  plastics  's-t-r-e-t-c-h 
'  slide  rule  dial  assembly."  To  be  honest,  however,  the 
best  praise  in  advertising  copy  is  reserved  for  the  vari- 

types  of  wood  cabinets. 

n  contrast  to  consumer  advertising,  Admiral  advertise- 
its  in  some  two  dozen  trade  journals  do  not  avoid  tech- 
ll  copy,  and  in  varying  degrees,  depending  upon  the  type 
periodical,  declare  the  merits  of  plastics,  along  with 
se  of  the  other  materials  used  in  making  the  product 
ng  advertised. 

suggesting  the  market  potentialities  for  plastics  in  the 
ale  appliance  and  radio  field,  the  capacity  of  Admiral 
tie  is  300.000  refrigerators  a  year  with  a  sufficient  supply 
materials  and  parts.  Lack  of  parts  is,  likewise,  all  that 
ps  the  company  from  turning  out  radios,  radio-phono- 
ah  combinations,  and  phonographs  at  the  rate  of  over  a 
ion  a  year.  END 


Teflon  Makes  Its  Debut 

(Continued  from  page  34) 


ters,  electronic  tire-patching  heaters,  and  certain  types  of 
ds. 

^though  still  being  produced  on  a  pilot-plant  scale, 
ited  amounts  of  Teflon  are  available  for  evaluation  by 
tomers,  in  the  form  of  rods,  tubes,  sheets,  beading, 
Icets,  and  thin  tapes.  Difficulty  in  fabricating,  and  high 
t  of  manufacture,  are  conditioning  factors  in  the  present 
pe  of  development  of  Teflon,  and  modifications  of  this 
sties  are  under  development  in  order  to  provide  materials 
ch  can  be  molded  on  injection  and  compression  machines 
l  little  difficulty.  These  newer  materials,  while  not  avail- 
:  for  evaluation,  are  likewise  to  have  good  electrical 
perties  and  chemical  and  heat  resistance,  according  to 
Pont.  END 


•rty 


Typical  Properties  of  "Teflon" 

Test  Result  Test  Method 


ciflc  gravity 2.1-2.3 D792-44T 

ile  strength  at  77°  F,  psi 2000-4500 D412-41T' 

gation  77°  F,  % 300-400 Die  C1 

ural  strength  77°  F,  psi 2000 D650-42T2 

ness  77°  F,  psi  (0.125") 60,000 D747-43T 

JCt  strength,  Izod,  — 70,  77,  170°  F, 

Ib/inch 2.0,  4.0,  6.0 D256-4 1 T 

dness,  D  Durometer 55 

pressive  strength,  psi  at  0.1%  de- 
lation   1 700 D695-42T 

d  temperature,  °F >320 Arl.  M-8 

'-distortion    temperature,   low    load, 

266 D648(b)-44T 

ciflc  heat  cal/g/°C 0.25 3 

flcient    of    expansion    per    °F    (77- 

<0) 5.5x1 0-5 D696-42T 

mal  conductivity   BTU/hr/ft  */°F/in. 
.18') 1.7.. 


. . .   Arl.  P-324 
. .  D746-43T 


eness  temperature,  °F <-l  00 

•ctric    strength,    short-time,    volt/mil 

.080") 480 Dl  49-40T5 

me  resistivity,  ohm-cm 1016 D257-38 

ectric    constant    60,    10s,    106,    108 
ides 2.0.  . 


er  factor  60,  1 0s,  1 06,  1 08  cycles . . .  <  0.0002 

er-absorption,  % 0.00 

ture  permeability  g/meter2/24  hr..  .0.00-0.5 

door  weathering No  detectable 


D150-40T 

D150-40T 

0570-42" 

....D697-42T 
change  in  1  yr. 


wile  strength  in  oriented  film  may  be  as  high  as  15,000  psi;  (3)  specimens  do  not 
k;  (')  method  of  mixtures;  |'|  Cenco-Fitch  apparatus;  (s)  1000-2000  volt  mil  in  5 
t-mil  thickness;  (*)  not  wet  by  water. 

3  given  represent  standard  commercial  grades  of  material  and  standard  methods 
sting  except  where  otherwise  noted). 


AQUA  PLASTIC  DYES 

(Potent  Pending) 


NEW  WATER-SOLUBLE 
DYES  FOR  CLEAR   PLASTICS 

Available  in  15  basic  color*  from  which  ISO 
completely  true  shades  may  be  obtained.  This 
method  can  be  used  by  the  fabricator  or 
molder  before  or  after  processing.  Inexpen- 

Heat  solution:  Simply  dip — rinse  with  water 
and  that's  all  —  No  expensive  equipment  or 
high  priced  chemicals  to  buy. 


(Acrylic  Cement).  Laminating  Dyes  (Col 
ored  Cement).  New  Sensational  "GAM 
CO"  Buffing  Compound— witl  not  burn. 


Phone  FEderal  1109 


GREAT  AMERICAN 
COLOR   COMPANY 

25?2  WfST  NINTH  STREET 


LOS  ANGELES,  CALIF. 


Canadian  R«pt  Colors  &  Finishes  Co.,  222   Front  Street,  East  Toronto,  Ontario 
New  York  R«p;   Plastics  Dye  &  Supply  Co.,  Ocean  Gate,  New  Jersey 

We  afeo  Atotturocfure  a  comp/efe  fine  of  Cold  dip  dyet. 


.Y  1946 


PLASTICS 


97 


UNIVERSAL  HYDRAULIC  MACHINERY  COMPANY 
Specialists  in  Hydraulic  Equipment 


HYDRAULIC  PRESSES: 

dia.   Ttm.  4  OMBlJus  100- we  CML  :  J — It'lK* 
I j4-jl|-,   •     dl&.    rmai.    75-tca  okp. :   1 — JO" 


tle  ft  ntf -«eot*in«d 
ill.  tl'xJl"  II" 
nm*.  Tl-ua  cap.: 
~_-^%-  **  " 


IW.  aui'jli   iWoPW   1M«*    Mtb"iw*«atral 
JMMii^TraT  I'M  OPS  sa«* 

285  Hudson   Street.   New  York  City 


NOW  AVAILABLE 
Special  Edition  of 

PACKAGING 

light  page t .   diituning  merchondiiing       fj  f 
application!  of  plaiticf  packaging  .  .  .       ••  JC 


$.nd  25<  in  catfi  fo 


ZIFF-DAVIS  PUBLISHING  COMPANY 

0«pf.  P.  A.  C.,  Circulation 
1«5  N.  Waba.h  Av«nu«  Chicago  1,  III. 


ROUTER  BITS— FORM  CUTTERS  and 
MACHINES  for  HIGH  SPEED  CON- 
TOUR and  STRAIGHT  CUTTING  PLASTICS 

StnJ  lor  Cmltlot  No.  43 

EKSTROM,  CARLSON  &  CO. 

1410   Railroad  An.  HOCKFORD.   ILL. 


"KRIEGR-O-DIP"— 

HOT  AND    COLD 
Dye*  lor  All  Types  ot  Plastics 

Manufacfurvd   ty 

KRIEGER  COLOR   &  CHEMICAL  CO. 

M*mb*r  ol  ih.  S.P.I. 

T.I.  Hlll.id.  7361  6531   Santa  Monica  Bird. 
HOLLYWOOD   38.    CAUT. 


AUSTIN  TOOL  &  MFG.  CO. 

1859  E.  63rd  STREET       -:-       CLEVELAND  3,  OHIO 
EXpreis  1000 

DHIGNI.S  PLASTIC  MOLDS 

Qyot.lioni  Within  4t  Hour. 


DUALL  MOLDING  CORP. 

l.j»c«lo.    ««<J    CoKpr.tu'o.    M.U.a 
Trp 


O.«m.»».l 
.»J    M.t.l 

C.mpUt.  To4H   Room  F*ciliti*i 
2*7-271    Wycfco*  St.  irooklyn.  N.  Y.          MAI*  S-112* 


FOR    SALE 

2 — BuHch-SulzfT     Hydraulic     CompreMlon     MoldlnR 

Pr*HC*.  capacity  150-200  ton*  each, 
t — 50-ton  Oil  Gear  Pumps  Included  with  above. 

CHARLES   I.    TAGER 
Consolidated  Staple  Co.,  Inc. 

14   W...I.T   it.  N,w   Vwh.  N.   V. 


r 


Better  Kitchen  Accessories 

i  Continued  from  page  59) 


vessel.    This  small  strainer  is  also  of  chromeplated 
molded  into  a  clear  polystyrene  rim.  and  fits  into  the 
\\hich  holds  it  securely  in  place  while  the  liquid  is  st 
through  it.    Standard  size,  it  is  designed  to  fit  the  la 
well  as  the  medium-sized  funnels  nude  by  the  compa 

In  producing  the  strainers  there  was  likewise  a  pi 
of  exact  positioning  of  the  delicately  curved  wire 
portion  during  molding.  Here  again  considerable  e 
mentation  was  involved,  with  skillfully  designed  dies  s 
the  problem  in  this  instance,  also. 

All  steps  in  the  making  of  these  products,  \\hii 
marketed  under  the  trade  name  of  Plasmetl,  are  prc 
by  patent — design,  dies,  shape,  construction,  etc. 

Furthering  its  efforts  to  supply  suitable  plastics  ai 
sign  in  inexpensive  kitchen  accessories,  the  Plastic 
Mfg.  Co.  affixes  to  its  sink  strainers,  as  well  as  to 
strainers,  an  informative  label.  This  label  tells  the  pur 
what  materials  are  used  to  make  the  strainer,  and  01 
briefly  the  qualities  and  characteristics  of  the  plastics 
with  demand  at  present  far  in  excess  of  supply,  offic 
the  company  feel  that  improved  design  and  suitable 
cation  of  plastics  materials  will  result  in  increased  a 
ance  and  understanding  of  plastics,  by  the  public. 


Patents  for  the  Asking 

(Continued  from  page  62) 


Powder.  Kurt  Gullich.  December  7,  1937.  This  inv 
deals  with  manufacturing  premolded  articles  patterned 
through  in  various  colors.  It  is  useful  in  the  manuf 
of  buttons,  walking  sticks,  umbrella  handles,  etc. 

2,107,637— Method  of  Making  Porous  Articlfs.  '. 
Lefebvre-Carnot  and  Leon  Pierre  Georges  Vautier.  I 
ary  8,  1938.  Relates  to  a  method  of  making  porous  cell 
articles,  such  as  artificial  sponges  in  which  porous  su 
are  produced  directly  in  the  process. 

2,122,089  —  Process  for  the  Manufacture  of  An 
Resins.  Werner  Conrad.  June  28,  1938.  A  techniq 
which  light  colored  artificial  resins,  completely  neutr; 
produced.  May  be  useful  in  the  manufacture  of  lac 
molded  articles,  and  as  impregnating,  tilling  and 
agents. 

2,127,404 — Process  and  Apparatus  for  the  Manuf  act 
Patterned  Articles.  Kurt  Gullich,  Germany.  Appli 
May  15,  1935.  Serial  No.  21,662.  Apparatus  for  sii 
neously  molding  a  plurality  of  objects  from  a  mass  of 
ing  powders. 

2,138,235 — Production  of  Moldable  Compositions. 
Pollak.  October  25,  1938.  A  process  by  which  well-fli 
molding  compositions  may  be  produced  without  the  nee 
of  the  baking  process.   Useful  in  die  casting. 

2,163,814—  Manufacturing  of  Jewelry  Set  with  S 
Daniel  Swarovski,  Austria.  Application  August  .*>, 
Serial  No.  98,459.  A  method  of  setting  ornamental  | 
by  seating  a  stone  within  a  mold  and  pouring  ;\  n 
plastics  material  into  the  mold,  while  prossiiij;  the  -tc 
place.  Of  interest  to  jewelry,  novelty,  buckle,  etc., 
facturers. 

-'.168,993  —  Expanding  Dei-ice  for  I  ubular  Knvt 
Alex  Joseph,  Netherlands.  Applii-:itn>ii  May  11.  l'M7 
rial  No.  142,655.  A  device  m.t<le  of  a  cellulose  com 
simplifying  the  manufacture  of  tubular  en\ elopes. 

J.  1 70,376—  Method  of  Stiffening  Shoes.  Karl  \i 
August  22,  1939.  In  the  use  of  various  iniprej;n.ite<: 


98 


ST  US 


.11  I.Y 


i  for  stiffening  toe-caps  or  heel-caps  of  footwear,  certain 
idvantages  are  encountered,  such  as  the  large  amounts 
solvents  required,  with  resultant  smeariness,  stains  and 
>erfect  adhering  to  the  leather.  This  patent  provides  a 
fanique  which  avoids  these  disadvantages. 
',,179,457 — Manufacture  of  Salts  of  Cellulose  Ether  Car- 
rylic  Acids.  Julius  Voss.  November  7,  1939.  A  process 
.  the  making  of  salts  of  cellulose  ether  fatty  acids,  by  re- 
ing  cellulose.  Useful  in  the  manufacture  of  dressing 
:nts,  thickening  agents,  adhesives,  etc. 
,,',187,817 — Inter  polymerization  Products  of  Vinyl  Chlo- 
e  and  Esters  of  Maleic  Acid.  Heinrich  Hopff,  Gustav 
inbrunn  and  Heinrich  Freudenberger  (I.  G.  Farben). 
mary  23,  1940.  A  process  for  the  manufacture  of  water- 
>of  plastics  with  good  machinability,  high  strength,  good 
v,  stability  to  heat,  light  and  acid,  and  high  electrical  in- 
ation  qualities.  The  process  is  also  helpful  in  the  manu- 
ture  of  films  and  foils. 

1,211,266—  Textile  Sizing.  Henri  Gibello.  August  13, 
fi.  A  superior  technique  of  sizing,  made  by  polymerizing 
yl  acetate.  Has  many  advantages  over  sizings  generally 
d,  such  as  gums,  mucilages,  and  glues.  Useful  as  sizing 

reverse  side  of  velvets  and  felts  used  in  hat  trade,  etc. 
,',212,433— Collapsible  Tube.     Alois  Brossette.     Oct.  5, 
17.    This  is  a  process  for  the  production  of  collapsible 
es.    It  consists  in  treating  a  sheet  of  a  transparent  cel- 
jse  derivative  with  a  solution  of  collodium  elasticum, 
umaticin  and  benzyl  alcohol  and  a  coating  material,  and 
n  winding  the  sheet  onto  a  cylinder  to  form  a  tube. 
,219,369  —  Condensation  Products.    Karl  Memminger. 
tober  29,  1940.  As  an  alkali  solution,  the  product  result- 
from  this  process  may  be  used  as  a  textile  assistant,  for 
jarting  wool-like  properties  to  cellulose  fibers. 
,227,637  — •  Impregnating  and  Insulating  Material.    Ru- 
)h  Engelhardt  (I.  G.  Farben).  January  7,  1941.  A  waxy 
ipound  which  holds  its  shape  at  temperatures  of  about 

C  and  is  therefore  useful  in  the  manufacture  and  main- 
ance  of  cables,  transformers,  and  the  like. 
,231,836 — Process  for  Producing  Sound  Records.   Wer- 

Zerweck,  Karl  Keller  and  Peter  Pinten  (I.  G.  Farben). 
jruary  11,  1941.  A  method  for  producing  sound  records 
laminating  paper,  which  has  been  impregnated  with  a 
atnine-formaldehyde  resin. 

237,240  —  Water-Soluble  Colloids  of  Urea-Aldehyde- 
"bohydrate  Ether  Products.  Kurt  Sponsel.  April  1,  1941. 
xress  for  a  product  useful  in  the  manufacture  of  adhe- 
;s,  binding,  thickening,  impregnating  and  dressing  agents, 

fillers  for  soaps. 

,254,638 — Method  and  Apparatus  for  Molding  Artificial 
.    Heiner  Wienand,  Germany.    Application  July  12, 


AUGUST  PRE-VIEW 

Jon't  miss  the  following  outstanding  features  in  next  month's 

plastics 

(1)  The   complete   story  of  a    newly-designed   electric   guitar 
utilizing    an    unprecedented    number   of   colorful    plastics 
parts. 

(2)  An  account  of  a  new  application  for  acrylics  in  the  mak- 
ing   of   lightweight,   transparent   splints   for   a    degree   of 
comfort  heretofore  unobtainable  with  metal  splints. 

(3)  A  survey  of  the  structure,  manufacturing  methods,  fabri- 
cation   characteristics,    and     properties    of    glass    fabric 
melamine   laminates. 


ll/l 


rror 


l/Ut 


lize  in  the  hard 


Specialize  in 
chromium  pl'ating.  of 
moulds  ana  dies  to 
finish. 


a.  mirror 


CHROME  SERVICE 


Save  It  with  Chromium 

9350  6RINNELL  AVE.      •      DETROIT  13,  MICH. 
Plaza  3164 

1926          Our  20th  Year  oi  Dependable  Service  1946 


On*  of  a  ftr/ei  covering  Wonders 
of  fhe  World.  Con  you  name  tome 
of  rh«  others?  Watch  NOICO'I  next  ad. 


WONDERS 

of  the 

WORLD 

The  lighthouse  of  Alex- 
andria, Egypt,  built  in  283 
B.  C.  stood  600  feet  high. 
After  standing  1  500  years 
it  was  destroyed  by  earth- 
quake •  Plastics  are  light 
and  colorful,  yet,  when 
properly  engineered  and 
used  in  their  rightful 
place,  they  are  strong  and 
durable.  Let  us  properly 
appraise  your  needs. 


NOSCO   IS  QUALIFIED   AND   CAN   HELP  YOU.  WRITE  TODAY 

NQSCO  P/o  sties 


0   I  V  !  S  I  O  N       OF 
NATIONAL      ORGAN      SUPPLY      CO 


ERIE,    PA 


1946 


PLASTICS 


99 


Advcrtiter 

Aaron   Machinery  Co. 

Accurate  Spring   Manufacturing 

Co 

Ajai  SlMl  I  Forge  Co 
America*  Molding  Po.der  i 

Chemical   Corp. 
Amos   Molded    Plastics 
Arrow   Plattici  Company 
A. born   Button  Wofki  IK 
Amtln  Toot  I   Mlg    Co. 
Bamberger.   A. 
Baftalen.    L     H 
Bellco  Plastics.  Inc 
Bolce-Craa*    Company 
Boonton  Molding  Company 
Brilhart.  Arnold,  Ltd. 
Catalin  Corporation 

C«o  l««   Mfg.  Company.  The 

Cello.Plastic    Chemical    Co. 
Callgplastic     Corporation 
Chemaco    Corporation 
Cl«rk.   Robert  H.,  Company 

Columbian   Rop*  Company   

Consolidated  Moldid  Products 

Corporation 

Consolidated  Stapla  Co  .   Inc 
Continental    Plastics   Corporation 
Cumberland   Engineering  Co. 
Defiance  Machina  Works.   Ine 
Deipatch  Ov«n  Company 
Detroit   Mold    Engineering   Co. 
Dow  Chemical  Company.  The 
Duall    Molding    Corporation 
Ekstrom.   Carlson   t    Co. 
Famco  Machina  Co 
Federal  Talaphona  and  Radio 

Corporation 
Feltenthal,   6..   4   Son. 
Flschberg.  Charlai  H    i  Co  .  Ltd. 
Fisher  Chamleal  Company 
General  Chamical  Company 
general  Electric  Co. 
General  Indintriat  Company.  The 
Caring    Product!   Inc. 
Girdler  Corporation,  Tka 


Agency 


Ruuell  T.  Gray.  Inc. 

Stockwell    1    Marcuse 


Sidener  and  Van  Riper,  Inc. 
Powered   Company.   The 
Charlei  L   Romrill  t  Company 


Gunn-Maan  Advertising  Agancy 
Raa.   Fuller   1   Company 
Wendt  Advertising  Agancy 
A.  J.  Slomanton,  Advertising 


Page 
ft 

12 
77 


101 
M 
W 
75 

100 
K 
87 
M 


Henri    L*   Moth*   Agency  Back   Cover 

Walter  J.  Gallagher.  Advg.   .Second  Cover 


McCarty   Company.   Th» 

M.   C.    Oiedrich 

R.  T.   O  Connall   Company 

West-Marquis.    Inc. 

(arlow   Ad'ertiiing   Agancy,    Inc. 


8« 

42 


Walter  J.   Gallaghar.   Advertising 

Jim    Duffy  Company 
Richard  Thorndlke  Precision  Advg 
taaion-Faller-Raichart,   Inc. 
Harold  C.   Walker  Advertising 
Charles  M.  Gray  t  Associates 
MacManus,  John  t  Adams,  Inc. 


102 

7 
N 
73 
71 

e 

101 
(I 
31 


Gunn-Maan    Advertising    Agency «8 

Cummings.   Brand  1    McPherson.   Advg.     VB 
Western    Advertising   Agancy  H 


Rickard    t    Company 
Liaber  Advertising  Co 

Fraiwald    t    Colaman    Advertising 

Atharton   i    Currier.    Inc. 

Banton  A   Bowles,   Inc. 

Fuller  a  Smith  aj   Roll,   Inc. 

M.    C.    Diadrich 

Roche.   Williams   I   Cleary.    Inc. 


43 

U 

n 

•5 
27 
13 
5 
M 


PLASTIC  MOLDS 

TO  EXACT  SPECIFICATIONS 

Every  Type  of  Plastic  Mold 
For   Injection,   Compression   and   Transfer   Molding 

15  Years  Experience  in  Designing  and 
Building  of  Plastic  Molds 

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PLASTICS  SERVICE  ENGINEERING 

2567  Wast  Orejnd  Blvd.    DITROIT   t,  MICH..   TYLH  7-2OSS 


PLASTIC    CEMENT 

Fast    Oryl.ej.   easily   epaJied.    ao    pre«issre   required. 
Fey  mounting  plastic  items  en  all  splay  cards, 

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/4re«7ao/e  lenenrfiaVe/y  ie  o*e  eW  Cre  ea//on  cans. 

INDUSTRIAL  co*f.  u.|TS..rcr?;:rT. 


TEXON 


-I-  M.  BATTALEN 

MSIftN.   MICH.   ING. 
MOBHS  —  HOIS  —  MOLDS 
TOOL     AND     DIE     MAKING 

J47    Wyck.ff    St.  Irooklyr.     N.    Y.  Moll    (.112* 


Advertiser 

Goodrich,  B.  F  .  Chemical  Co 
Grays    Harbor    Industries.    Inc.    .  .  . 
Great  American  Color  Company 

Grigolait  Company.  The 

Hassall.  John.  Inc 
Hy. Speed    Prass    Company.    Inc. 
Hydraulic   Prou  Mfg.  Co..  The 
Interlake  Chamical  Corporation     . 
Kingslay  Gold  Stamping  Machina 

Co 

Kirk,  F.  J.,  Molding  Co. 
Kreiger  Color  I  Chamical  Co. 
Kuhn  *  Jacob  Molding  1  Tool  Co. 

Kurz-Katch,  Inc 

Lester-Phoenix,  Inc 

Mack  Molding  Company,  Inc. 
Magnetic   Plastics  Company,  The 
Michigan  Chroma  1  Chamical  Co. 
Mosinaa   Paper   Mills  Company 

National  Lock  Company 

National  Organ  Supply  Co. 
National  Plastic  Products  Co.,  The 
Nlcholl  Hard  Chroma  Service 
Plaskon  Division,  Libbey-Owans- 

Ford  Glass  Company 
Plastic    Enterprises.    Inc. 

Plastics  Products  Co 

Plastics  Service    Engineering 
Radio  Receptor  Company.  Inc. 
Rathbun    Molding    Corporation 
Rayon  Processing  Co.  of  R.I.  Inc. 

Rohm  t  Haas  Company 

Schwarti  Chemical   Company 
Siagel.  M.  B.  Associates 

Sossner  

Stokas.  F.  J.,  Machina  Company 
Tennessee  Eastman  Corporation 
Teion    Industrial   Corp. 
Universal  Hydraulic  Machinery  Co. 

Univanal   Plastics  Corp 

Van  Dorn  Iron  Works  Co.,  Th«  . . 
Watertown  Manufacturing  Co. 
Worcester  Moulded  Plastics  Co. 
Wriglay,   Wm  .   Jr.,    Company 
Yardlay  Plastics  Co. 


Agency 

Griswold-Eshlaman  Co.,  The 
Frederick  E.  Baker  and  Associates  . 

Mace    Advertising    Agency.    Inc 
Anderson,    Davis  t    Platta,    Inc 

Jay  H    Malsh  Company,  The 
Stanley    Ptlaum   Associates 

Continental   Advertising   Service 

Cory  Snow,   Inc. 

Warren   P.   Fehlman  Adv.  Co. 

Eldridge-Northrop.    Inc. 

Kircher.    Helton    I    Collett 

Gregory   House.    Inc 

George   Homer   Martin 

Gregory    House.    Inc. 

Karl  G.    Bahr  Advertising   Agency   . 

Klau-Van  Pietersom-Dunlap  Assos  .  I 

L.  W.  Ramsey  Advertising  Agency.  1 

P    W.    Price.   Advertising 

Joseph  A.  Wilner  Company.  The 


Meldrum  I   Fevnmlth  Advertising 
A     F.    Ligotti    Advertising 
John  A.   Finneran 

Richard  Thorndika  Precision  Advg. 

Nawell-Emmett  Company 

Walter   W.   Wiley  Advertising 

Craig  E.  Oennison  Advertising  Agei 

Ehrlich    (    Neuwirth 

McLain   Organization,    Incorporated 

Kenyon    t    Eckhardt.    Inc. 


Gunn-Mears    Advertising    Agency 

Cayton,    Inc. 

Hubbell   Advertising   Agency,  The 

R.  T.  O'Connall  Company 

C    Jerry  Spaulding,  Inc.  Third 

Ruthrauff  1  Ryan,  Inc 

Iyer  I  Bowman  Advertising  Agancy 


CLASSIFIED    ADVERTISING 


H>ni  Cmlty  ComprtMlon  Mold  for  baby  fading  bowl  and  Eltiht  i 
(  .impression  Mold  for  b«by  feeding  cup.  Ar*»  24jJ4.  Molds  testi 
nm  u*fd.  Molds  »r»  In  absolute!*  perfect  condition.  Price  $4!50.M 
ply  Boi  »5.  %  Pintle*.  185  N.  Wabajsh  An..  Chicago.  111.  _  . 


I.AIll.K     |>i:illtlt>      •!    MI;!'    Ili.pi.-I    Ii.nlilnu    :i..il.-:i.il    -'ilt.il.l.-    f..r    lltnlni 

blank*.  Industrial  cuter*,  etc.  Box  »4,  %  PluUct.  18S  N.  Wtbuh 
Otaco.  in._  _  j 

1-nKKIl    (  -I,,,,    \1.,|,l.    r,,n,|ir.^^l..ii      MII!.I|.|I-    t,.r    ii,.«dfr     ,.r    prr-furra 

l»i«  dla.  x  H-»qua.re  ed(e—  Interlock)  n(  design—  Mold  channeled  for  i 
top  and  bottom,  complete  with  knock  out  bars.  Mold  In  A-l  <-on< 
Mold  size  16x20  36  Car  Compression  Mold  for  Paring  Knife  Ri 
Blade*  molded  a»  Inserts  Into  handles,  eliminating  awmhly  and  « 
Ing  operations.  Mold  I*  practically  new.  In  A-l  condition.  Mot 
15x30.  Plastic  Products  Company,  1W  So.  La  Brea  Are..  Lo*  Angal 
CaJIf.  _  j 
Hill  SAI.K  <  alr-n.li  •-.  ll!'ii.n,i:l,.iii  !">.••,  foul  roll  «li.«-  .  .I|.M',|.T  It 
operating  condition,  i-nmplete  with  motor.  Box  M.  %  Plastics.  1 
Wahash  Are  .  Chicago.  Ill 

SITUATIONS    WANTED 

(  IIKM1CAI,  Knilneer     7  j»ar»'  experience  In  proc»»s  derelopment  a. 
diKtrlal    supervision    In    organic    chemicals    and    Inorganic    acid*. 
trained  In  personnel  relations  and  safely     Desires  position  In  plastic 
In  process  derelopment.  production,  or  technical  salea.    Age  M,  M 

11    -        .     .    I        \       I  •     M,.  '          II  •     |  Hut   •       lw»   »      Wal.J^I. 

Chicago.  III. 

HELP    WANTED 

WANTED  —  Experienced  Injection  Molding  Supers-lsor.  Kxcellent  i 
lunlly  for  qualified  applicant  to  awime  complete  supervision  of  pi 
mid  south  city  Must  be  thoroughly  familiar  with  all  thermopl 
molds  and  machinery.  Furnlfth  complete  Information  concerning  I 
me*,  qualification*  and  salary  expected  Box  81.  %  Plastics.  IK 
x\.ii....t,  A..  Chicago  1  in  _  j 

EXCELLENT  Plajstlc  Opportunlnr,      Top  notch  plastic  man—  tkori 
eiperlenrvd   In   all    phases   of   Injection   molding      To   net   up   and   • 
operations   of   Injection    Molding    Division   of  Large    New    England 
farturer       Immediate   employment       State   past    experience    and    rr-fe 
available       All    Information    wilt    I*    held    In    strictest    confidence 
IBM.    Pawlucket.    R     I 


100 


JULY 


1938.  Serial  No.  218,725.  A  molding  device  by  which 
plastics  teeth  may  be  formed. 

2,256,253 — Production  of  Protein-Containing  Urea-For- 
maldehyde Plastics.  Oscar  Neuss.  September  16,  1941.  A 
process  for  the  manufacture  of  cheap,  moldable  plastics. 

2,285,178 — Polyamides  Combined  with  Cellulose  Deriva- 
tives, Kurt  Thinius.  June  2,  1942.  A  process  for  the  manu- 
facture of  clear  cellulose  derivative  films.  Useful  in  the 
making  of  films,  novelties,  adhesives,  and  surface  coatings. 

2,302,160 — Process  of  Producing  Duplicate  Sound  Bands. 
Hugo  Westerkamp.  Jan.  6,  1941.  A  technique  for  duplicat- 
ing mechanical  sound  records  by  treating  a  thermoplastic 
blank  record  with  a  volatilizable  softening  agent  and  press- 
ing it  against  an  original  record  under  heat. 

2,320,937 — Urea  Aldehyde  Adhesive.  Herbert  Knoop,  et 
al.  Nov.  25,  1939.  A  process  for  adhesively  uniting  rubber 
and  rubber-like  masses  with  surfaces  of  other  materials  by 
applying  a  coating  consisting  of  a  urea  aldehyde  condensa- 
tion product  and  an  iron  oxide.  Result  is  a  vulcanized-like 
adhesion. 

2,332,938  —  Automatic  Mold  Filling  Device.  Heinrich 
Schmidberger,  Germany.  Application,  May  28,  1940.  Serial 
No.  337,676.  An  improved  automatic  technique  for  filling 
molds. 

2,332,955 — Method  and  Apparatus  for  Making  Artificial 
Sponges.  Leon  Pierre  Georges  Vautier,  France.  Applica- 
tion December  30,  1939.  Serial  No.  311,909.  An  extrusion 
device  for  molding  artificial  sponge-forming  compositions. 

2,345,112 — Method  of  Molding  Plastic  Layers.  Frantisek 
Grundel,  Bohemia.  Application  May  28,  1941.  Serial  No. 
395,688.  A  process  for  producing  raised  patterns  on  the 
surface  of  plastics  articles.  Useful  in  the  production  of  toys 
and  novelties. 

2,349,977 — Comb  Mold.  Lucien  Mazzoni,  France.  Appli- 
cation March  18,  1941.  Serial  No.  384,011.  A  molding 
device  for  manufacturing  combs  of  plastics  materials. 

2,350,772 — Device  for  Covering  Electric  Wires.  Fried- 
rich  Klute  and  Harry  Heering.  Dec.  10,  1938.  A  method 
and  process  for  covering  electric  conductors  with  plastics 
of  great  tenacity  by  forcing  the  conductors  to  pass  between 
a  number  of  calender  rolls  which  apply  the  material. 

2,356,585— A  Mold  for  Steering  Wheel.  Emil  Hempel. 
Dec.  3,  1940.  This  is  an  injection  mold  comprising  a  rim 
cavity,  a  hub  cavity  and  interconnecting  spoke  cavities. 

2,360,680 — Spinning  Nozzle  for  the  Production  of  Arti- 
ficial Hollow  Threads.  Hermann  Holzmann.  Feb.  12,  1941. 
This  is  a  technique  and  a  device  for  producing  hollow  and 
very  thin  filaments  from  rayon.  END 


I 


Beauty  in  Fabrics 

(Continued  from  page  78) 


first  use  going  to  International  Detrola  Corporation,  which 
has  engineered  the  material  into  two  new  models. 

"Built  in"  color  is  another  important  point  in  Saran 
fabrics.  The  monofilaments  are  extruded  in  both  transpar- 
ent and  opaque  types,  and  pigments  and  dyes  may  be  added 
to  the  fine  molding  powder  before  extrusion.  From  the  deep 
jewel-like  shades  to  delicate  pastels,  the  color  is  "all  the 
way  through."  They  are  extruded  by  Saran  licensees : 
National  Plastic  Products  Company  of  Odenton,  Maryland, 
and  Visking  Corporation  of  Chicago. 

Regarding  Saran  multifilaments,  Donald  L.  Gibb,  head  of 
Dow's  plastics  sales  division  said,  "These  are  still  very  much 
in  the  development  stage.  Anything  that  the  public  has  seen 
to  date  in  the  way  of  fabrics  woven  of  Saran  multifilaments 
is  simply  an  advance  showing  of  what  is  hoped  will  someday 
become  a  commercial  application."  END 


Rapid 

Dependable 
Trouble-Free 

PREHEATING 


with  a  Despatch 
Oven 

•  Designed  for  rapid 
heat  transfer,  this  plastic 
preheating  equipment 
assures  positive  moisture 
elimination  from  pow- 
ders, granules  and  pre- 
forms. .  .  .  Adaptable  to 
single  and  multiple  press 
operation  a  Despatch 
oven  won't  shrink  preforms 
in  heating  .  .  .  insures  dimen- 
sional stability  .  .  .  prevents 
brittleness  in  finished  product. 


Available  in  4,  6,  8  and  W-drawer 
models  for  bench  on  stand  mounting. 
Electric.  Forced-convection  cross 
flow  heating.  Average  overall  size 
40"  wide,  35"  deep,  66"  high. 
Drawers  are  12"  x  24"  x  2:I4  ". 

WRITE  TODAY  for  complete  bulletins 
or  see  your  Laboratory  Supply  Dealer. 


Despatch  Micromatic  Ther- 
mostat controls  heat  to  obtain 
heat  uniformity  as  close  as 
y%°  F.  Simple,  shock-proof, 
and  with  wide  heat  range. 
Cabinet  inclosed 


JULY  1946 


PLASTICS 


101 


* 

Designed  by 


Philip  I. 

of  Cox  &  Stevens 

for 

Donald  B.  Abbott 
* 


Mass-Molded  in  one  piece  from 

IO"RO"LITEThe  R°pe  Fibre  plastic 


CO-RO-LITE  economy  starts  with  the  pre-form, 
which  eliminates  costly  lay-up!  Curing  speed  is 
so  fast  that  there's  another  big  saving  over  other 
materials.  Remember,  too,  that  CO-RO-LITE  is 
readily  prr-formrd  and  molded  into  compound 
curves,  deep  draws,  angles,  channels,  and  large 
shells! 

CO-RO-LITE,  the  Rope 
Fibre  Plastic,  is  a  ready- 

«  t  \^W  to-mold     thermo-setting 

r^  .  «  c  plastic-   compound.    It   is 

equally    effective   with 


fluid  pressure,  high  pressure,  flash,  or  transfer 
molds.  Long,  tough,  interlocking  rope  fibres 
reinforce  all  sections  of  the  molded  unit,  im- 
parting great  impact,  flexural,  compressive,  and 
tensile  strength  in  a  range  of  densities  compar- 
able to  wood.  CO-RO-LITE  may  solve  your 
problem:  Write  us  for  full  information. 

CO-RO-LITE  —  Rope  fibres  impregnated  with 
tli.-rino-responsive  resin:-  Product  and  process 
patented.  Patent*  No.  2,249,888  and  No. 
2,372,433.  Other  patents  pending.  Co-Ro-Lite 
Boat  Patent  No.  2,376,753. 


COLUMBIAN     ROPE     COMPANY 

500-92  Genesee  St.,  Auburn,  "The  Cordage  City,"  N.  Y. 

Canadian  Licensee.-  Canadian  Bridge  Engineering  Company,  Ltd.,  Box  157 
Wofkervi/fe,  Onfario,  Canada 


PRINTKn   IN   r  S  A. 

PI.ASTH  » 


JULY   1916 


rt  D" 


Ability  to  develop  parts  or  finished 
•oducts  to  the  customers'  exact  require- 
ents,  and  extensive  facilities  for  Custom 
jection  Moulding  in  volume  quantity  - 
iese  are  the  reasons  so  many  plastics 
roblems  have  been  answered  at  Worcester 
toulded. 

Skillful  engineers,  expert  die  designers 
nd  die  makers  enter  into  your  search  for 
fility  or  beauty,  or  economical  production, 
st  as  if  your  problem  were  our  own.  An 


WITH  A  CAPITAL  "P 


enviable  record  of  achievement  for  leading 
manufacturers  stamps  this  experienced 
and  efficient  personnel  as  pacemakers.  They 
are  leading  many  firms  to  new  heights 
and  new  profits  in  plastics  applications. 


Vaafom  Jrtuec&on 

WORCESTER  MOULDED  PLASTICS  CO. 

14  HYGEIA  STREET,  WORCESTER  8,  MASS. 

17  East  42nd  St.,    New  York   IT,  N.  Y. 


MiddU          k     i     i      -  Neck,  N.Y.   •    Phone:  Gixut  N^cK  4054 


AUGUST 
1946 


From  a  well-developed 


the  ELECTROAIRE   breathes  purifying  Ozone  into  room  atmosphi 


Purified  mountain-top  Ozone  comes  down 
to  earth  to  serve  the  home.  One  of  the 
promises  of  the  future  — now  here! 

Housed  in  a  smartly  designed,  gem-like, 
colorful  Catalin  cabinet,  the  Electroaire 
functionally  transforms  indoor  air  into  "the 
breath  of  the  great  outdoors".  It  destroys 
smoke  and  food  odors;  refreshes  stuffy 
atmosphere,  promotes  health.  The  Electro- 
aire is  portable  —  you  connect  it  as  you 
would  a  table  radio  —  it  may  be  moved 
from  room  to  room.  Decoratively,  as  an 


appointment,  it  also  contributes  a  qualify 
atmosphere  of  beauty,  luxury  and  fitness. 
This  application  of  Catalin  is  that  of  a 
simple  draw  casting,  the  grill  openings 
being  provided  in  the  arbor.  Catalin  cast- 
ing techniques  are  now  so  highly  advanced 
as  to  place  no  restrictions  upon  a  projected 
product's  size,  shape  or  intricacy  of  design. 
With  Catalin,  you  incur  no  expensive  cus- 
tom mold  costs.  In  many  instances,  stand- 
ard Catalin  shapes  satisfy  product  speci- 
fications. The  members  of  our  experienced 


staff  gladly  welcome  an  opportuni 
lend  a  hand  to  those  who  are  planni 
manufacture  products  of  plastics. 

CATALIN      CORPORA! 

ONE  PARK  AVENUE.  NEW  YOIK  I* 
•Monvfortvrx/  by  f  l£CT»O*/»f  CO*'.,  I.  /.  C,l 


CAST    RESINS    •     LIQUID    RESINS     •     MOLDING    COMPOUNDS 


~ 

Door  Chime  Houiing.  Wl:  7-1/4  ois 
Production:   60,  h 


Toilet  Tinue  Fixture.  Wt:  5  on 
Production:  60/hn. 


PROVEN    DESIGN    for 

MOLDING    POLYSTYRENE 


fewel  Bar  Bracked.  Wt:  4-3/4  on. 
Production:  360  brkti/hr. 


I 


I:  2-3/4  on.  Production: 
205  hook>/hr. 

ip  Diih.  Wt:  3-1/2  on.  Production: 
_— ~          180  di»be»/hr. 


The  new  16  ounce  injection  machine 
illustrated  above  is  one  of  several 


Products,  Inc.  This  custom  molder  specializes  in  the  production  of 
polystyrene  parts.  At  left  are  depicted  typical  polystyrene  moldings 
made  with  their  H-P-M  machines. 

Now  is  the  time  to  replace  your  obsolete  injection  machines.  Have 
you  investigated  the  efficiency  of  each  machine  in  your  molding  plant? 
Are  repairs  and  down  time  "eating  up"  your  profits?  New  H-P-M  in- 
jection machines  will  lower  your  manufacturing  costs!  Call  in  an 
H-P-M  engineer  today  to  discuss  your  particular  problems.  Built  in 
stock  quantities,  H-P-M  machines  can  be  delivered  promptly  in  any 
standard  size  —  4,  9  or  16  ounce  capacity. 

THE    HYDRAULIC    PRESS    MFG.    COMPANY 

Mount   Gilead,   Ohio,   U.S.A. 

tiruftcn    Offices  in   New    York.  Philadelphia.   C/eve/ond,   Cincinnori,   Defroif  and  Chicago. 
«  epreien  toti  ves   in   other   principal    tifiei. 


INJECTION  MACHINES 

FOR    MOLDING    ALL    THERMOPLASTICS 


M 


REVOLUTIONIZING     PRODUCTION     WITH     HYDRAULICS     SINCE     1877 


AUGUST,    1946 


plastics 


in  this  issue 

Piano*  Adopt  Plastic* William  Schack 

lnj,Tii..n  Mold  Design,  Part  IV •/»*"  G.  Robb 

B.-tter  "Pick-Up" 

Know  Your  Acetate* W.  O.  Bracken 

An  Interpretative  Survey  of  German  Plastics  Fiihriration,  Part  V.  . . 

W.  C.  Goggin     34 

40 
44 


15 
20 
26 
28 


I  ,-xtilr*  on  the  Wall Richard  L.  Bean 

Glamorizing   the   Guitar. 


Container  Fabrication,  Part  III Mel  Meyers 

Modernizing  Instruments Jennie  R.  Zachs 

New  Mix  for  Castings J.  S.  Offutt 

Opportunities  in  Costume  Accessories Louise  Sanders 

Glass  Fabric  Melamine  Resin  Laminates C.  J.  Straka 

»|.lim-  I  till,"-  I'l.i-iii  - W.  /,.  Siffihi'n 

Versatile  Vinyls  Find  a  New  Application J.  L.  Fosti-r 

A  New  Method  of  Repairing  Sailboats 79 

Slitting  Film  to  Size 83 


46 
50 
55 
58 
62 
71 
75 


departments 

I'l  i-t i.  -    in    Perspective 12 

On   the    Drafting    Board 43 

I'la-n.-   at   Work 60 

Inilu-lry   Hiichlighln    84 

People   87 

Problem»    in    Plastic* 89 

Stall-lira!   Data  . 


What's  New  in  Plastics 90 

Literature  Review    92 

Plastics  Overseas    94 

Engineering   News   Letter 96 

Association  Activities   98 

The  Plastics  Library   99 

..101 


COPYRIGHT.    1946 


ZIFF-DAVIS  PUBLISHING  COMPANY 


Editorial  Officei.    185  N.  Wabash  Ave.,  Chicago   I. 


WILLIAM  B.  ZIIT 
PuUtinrr 


1.  G.  DAVIS 
(ffneral  Manager 

HERMAN    R.    BOLLIN 
An  Director 

H.  O.  STRONG 


C.  R.  TIGHE 
An' I.  to  Publisher 

GEORGE  BERNER 
Advertising  Director 

H.    1.    MORGANROTH 
Production   Director 


Audit  Igretu  of 
Circulation! 


VOLUME  5,  NUMBER  1 

IDirOKIAL 


MICHAEL    H.    FROEUCH 

Editor 

WILLIAM  SCHACTC 

Field  Editor 

T.  E.  GIBBERS 
Associate  Edit  fir 

M    CHURCH 
Associate  Editor 

ULA  SHAFFER 
Associate  Editor 

GAITHER  UTTHELL 
Witt  Coast  Editor 

FBED  HAML1N 
Washington  Editor 

CHARLES  A.  SCOGLAND 
Consulting  Technical  Editor 

WALTER  STEINHARD 
Staff  Photographer 

ARTHUR  E.  HAUG 
Stag  Pholografhrr 

SYDNEY   BARKER 

Art  Editor 

ADVERTISING 


JAMES    A.    CERBONE 
Eastern  Advertising  MaHayi  * 

ROY  E.  LINDER 
Midwest  Advertising  Manager 

WILLIAM  L.  PINNEY 
Western  Advertising  Manager 

BKANCH      Off/CCS 

NEW  YORK  (1) 

Emfire  State  Bldg  .  H  7  7-0401 

LOS  ANGELES  (14) 
11}  S.  Hill  St..  TUcktr  9113 

WASHINGTON   (4) 
International  ttlda..  EXEcntiff  .'< 

TORONTO 
21  King  Street,  East 


COVEH 

Graceful  linet.  harmonl- 
oua  coloring  and  good 
lonal  quality  arc  diillnc 
li»e  leature«  oi  new  plas- 
tics "Ullralone"  electric 
guitar  (»•«  "Glamaritinq 
Ihe  Guitar."  paqe  44). 
Photo  by  Arthur  E.  Hauq 


. 
Othtr  Ziff-Davit  Publications:  Hying.  Popular  Photography,  Radio  Newi,  Radio-Electronic  Engineering. 


M*  Otwtml  AttwrMM,  f 


!•  I.. IfiTU'S 


M  i.'  ST 


When  you're  on  the  green,  a  putter  and  putting  stance  are 
"essentials"  for  holing  out  .  .  .  and  experience  is  equally  essential  for 
consistent  results.     In  the  creation  of  essential  papers  for 
industry,  MOSINEE  paper  technicians  concern  themselves 
with  the  job  you  want  paper  to  perform 
for  your  product  .  .  .  and  the  technique  of 
your  processing.  Through  years  of  successful 

f  experience  in  controls  of  maximum-minimum  pH, 

9  uniform  specified  density,  high  tensile  strength, 

specified  dielectric  strength,  moisture  repellency  and  other  vital 
paper  characteristics,  MOSINEE  consistently  gets  results  that  improve  products 
and  processing.    That's  why  many  manufacturers  rely  on 
MOSINEE  as  a  dependable  source  for  industrial  papers. 


PUTT 

WITH  A  DRIVER? 
No 


OSINEE 

MOSINEE  •  WISCONSIN 


PAPER 

MILLS 

COMPANY 


Please  address 
your  letter 
Attentinn 
Deft.  H  ' 


lUGUST    1946 


PLASTICS 


fat  Jbo   "3(jww  JAjp  fop&&"—lD  Stay   Oui 


/ 


< 


—and  GERING 


i&  w&tl 


For  twenty  years,  Gering  ingenuity  in  methods  and  in  cold  logic 
has  devised  many  improvements  in  reclaiming  and  vitalizing  what 
was  once  known  as  "waste"  in  Plastic  production.  Today  most  of  the 
residue  sent  to  Gering  for  "rehabilitation"  is  converted  to  practically 
prime  powders. 

It's  not  only  in  knowing  whaf  to  do,  but  how 
we  do  it!  Cleaned,  de-metalized,  ground 
and  plasticized, — it  pays  to  have  the  GP 
treatment  for  your  scrap! 

Send  us  a  sample  for  prices  .  .  . 
Telephone:  CRanford  6-2900 


GERING  PRODUCTS,  Inc. 


NORTH  SEVENTH  ST. 


I tlfmtfrM  oj     lilfKjic   in  '  C  Arrifio/i/«»/ic 
HABTICM 


KENILWORTH.  N.  J. 


cont'crsion 


\V(,l  ST 


THIS  IS  NOT  A  PICTURE 
OF  A  PURCHASING  AGENT 
WATCHING  HIS  COSTS 


CAR  from  it.  All  the  Purchasing  Agents  we  know  are  nice  looking,  keen  business 
men,  with  sunny  dispositions.  t 

Perhaps  that  is  because  many  of  them  buy  from  us  their  plastic  moldings  and 
sleep  well  nights. 

They  know  of  our  well  organized  planning  department  that  follows  their  jobs  thru 
from  the  time  the  order  is  received,  that  keeps  them  posted  and  makes  our  promises 
live  things*. 

They  know  about  our  staff  of  engineers  skilled  over  the  years,  and  oar  equipment, 
ample  and  modern. 

Do  you  place  your  orders  for  plastic  moldings  and  promptly  forget  them  with 


a  clear  conscience? 


t. 


Phone  our  New  York  office  for  a  talk  about  your  problems.  We  are  specialists  in 
custom  molding  ...  no  axes  to  grind. 


Our  "Ready  Reference  tor  Plastics"  is  yours  if  it  will  help  you  buy  or  design  plastic  moldings. 


BOONTON    MOLDING     COMPANY 

MOLDERS  OF  PLASTICS   •    PHENOLICS   •    UREAS    •    THERMOPLASTICS 

122  EAST  42nd  ST.,  NEW  YORK  17  •  Murray  nm  e-ssu 

FACTORY- BOONTON,  NEW  JERSEY 


•JGUST  1946 


i'l.ASTtCS 


THE 


CHAMP 


Heats  6  Pounds  (96  ozs.)  in  ONE  MINUTE 


Whenever  you  see  the  THERMALL  Diamond  on  an 
HF  Heating  Unit  you  can  bet  your  last  dollar  on 
the  irfmoif  in  performance. 

We'll  gladly  give  you  technical  and  engineering 
data  about  every  size  THERMALL  Unit  Users  say 
that  we  are  conservative  in  our  power  ratings. 
They  tell  us  that  THERMALL  HF  Heating  Units 
consistently  deliver  more  than  rated  power;  preheat 
faster  than  we  claim. 

Time  oiler  time,  users  have  said  they  were  "amazed 
at  THERMALL  performance." 

If  you  have  a  pre-heating  or  molding  problem  oi 
any  kind  and  want  technical  advice  or  assistance 
— write  us.  We  will  assist  you  by  assigning  one 
oi  our  technical  representatives  to  your  problem 
without  obligation. 

When  you  want  a  job  done  day  in — day  out  re- 
member thai 

THERMALL  means  PERFORMANCE 


'** 


The  THERMALL  Champ  occupies  only 
20x30  Inch**  oi  your  floor  *pace.  Healt 
96  ounce*  compound  to  molding  temper- 
ature In  1  minute.  Completely  portable. 

Bulletin       give*    ipeclflcatlon*    and   detail*   ol 
all  THERMALL  HF  Unit*.     If*  tree,  on  requeet. 

W.      T.      LA      ROSE      &      ASSOCIATE 

635   Second   Avenue  Troy,   New  York 

Repreientatlvet  in  All  Principal  Cltlei 
E  •  port:    Omni  E i port  Corp..  40  Eait  34th  St..  New  York  16.  N.  Y. 


8 


!•  I.. 1ST  ITS 


.vrcrsT  is- 


/O 


Youth  will  be  served  by  Styron — and  served  well!  For 
this  Dow  plastic  makes  toys  gay  with  lasting  colors.  It 
simplifies  design.  And  it  assures  easy  functioning  because 
its  rigidity  endures. 

In  this  mechanical  building  set,  Styron's  bright  reds,  deep 
blues  and  vibrant  yellows  capture  children's  fancy.  And 
its  warmth,  smoothness  and  lightness  make  toys  pleasant 
to  handle. 


Styron's  design  adaptability  results  in  parts  that  are  readily 
put  together  without  complications  of  nuts  and  bolts.  Yet 
Styron  has  soundness  that  makes  toys  work — and  last.  And 
Styron  is  sanitary,  safe. 

This  building  set  is  an  example  of  the  big-step-forward  that 
toy  manufacturers  are  taking  with  Styron.  It  reveals  the 
product  advancement  that  Styron  can  bring  to  you! 


Success  in  nla&tics  is  best  measured  in  end 
products,  h  calls  for  combined  efforts  of 
manufacturers*  designers*  fnhricuMrs.  run- 
material  producers.  Dou  is  ready  tit  do  its 
part.  Save  time  and  money  -nttl  on  Dotttondgei  the  inoM 


PRESENT  AND  POTENTIAL  USES     l.isbtinj;  I, 
ters;    runnels;    closures:    food    handling 
and  jewelry   containers;   co-lnmr   jewelr 
liens;    pencils;    liijuor    dispensers;    e-enl 
tangos;  decorattvo  objects,  trim. 
PROPERTIES  AND  ADVANTAGES  Clear.  Iran 


Inn--:  insulators;  i)atlcri<'s;  li\(iro 

(juipment;  pharmaceutical,  ro 

;   tcty1^:   novelties;   refrigerator   part 

hen ii:-:    chemical    apparatus;    di>rn 


lucent  or  op;ic|ue:  liroad  color  ra: 
can    "(lipe"*    light    I hr» 


excellent    for    hifjll    frei|nency    electrical 

curved  rod,  and  around  corners;  rcsi-lant  to  acids  and  inanv  alkalies;  lo\\  \v 

alisorjition ;  li^iht  weight;  stable  at  low  teni|ieraltire^.  limited  solvent  resistan 

PLASTICS    DIVISION     .     THE    DOW    CHEMICAL    COMPANY      .     MIDI  AND     MICHIGAN 


JOW 


PLASTICS 


ETHOCEL      •    ETHOCEL   SHEETING 
STYRON      •     SARAN      •     SARAN   FILM 


intricate  metal  shapes  made  inexpensively 


Now  the  fanciest  metal  shapes,  imaginable, 
can  DC  made  quickly  ana  inexpensively. 
Ali.lilrd  or  fabricated  plastics  Aletaplated 
precisely  to  any  desired  thickness  witli  any 
kind  ol  metal  Iinish  oner  manufacturers  tlie 


ideal  method  of  large  scale  production  of 
line  merchandise  at  low  cost.  M.etaplast 
ha»  many  processes  for  metal  finishes  on 
plastics  .  .  .  our  engineering  department  -will 
ne  glad  to  discuss  such  problems  with  you. 


a*#exquisite  shiny  colors  applied   to  roll   acetate   or  cellophane^** 


COMPANY  INC. 


Col.lo.-..     1077  N 


205  W.  1 9th  ST..  N.Y.  II.N.Y. 

f  NGIAND  •  FRANC!  •  CANADA  •  AtGENTINA  •  MAZIl  •  AUSTRALIA 


METAL        PLATING        ON        PLASTICS 


10 


PLASTICS 


AUGUST  194« 


. . .  THE  FINAL  TOUCH  OF  PERFECTION  THAT 
MAKES  PLASTICS  SELL  FASTER! 


Plastics  look  their  best,  and  sell  fastest,  when 
they  have  the  added  surface  beauty  of  a  very  fine 
finish  like  CODUR. 

CODUR  is  a  line  of  high-gloss,  synthetic  baking 
enamels  especially  designed  for  a  one-spray  coat 
application  on  molded  (phenol  formaldehyde) 
plastics.  They  have  excellent  color  retention  and 
bake  to  a  very  hard  mar-resistant  surface.  CODUR 
is  available  in  most  colors  in  plain  enamels  and 
many  metallic  colors.  M  &  W  also  offers  air-drying 
or  baking  finishes  for  other  plastics:  acetates,  buty- 
rates,  methacrylates  and  others. 


SERVICE  THROUGH 
RESEARCH  AND   EXPERIENCE 

Whatever  the  material,  sim- 
ply submit  a  sample  of  your 
plastic  and  we'll  recom- 
mend the  proper  finish.  70 
years'  experience  and  our 
fine  research  facilities  are 
at  your  service.  Contact  any 
of  our  offices. 


PIONEERS  \  M.&WC?/     IN  MOTECTION 


NEWARK  4, 
NEW  JERSEY 


MAAS  &VWALDSTEIN  COMPANY 

1658  Carroll  Ave.,  Chicago  12  •  6  Jersey  Sf.,  Boston  15  •  1228  W.  Pico  Blvd.,  Los  Angeles  15 
PRODUCERS  OF  LACQUERS,  ENAMELS,  SYNTHETICS  AND  SPECIAL  PRODUCTION  FINISHES 
AUGUST  1946  PLASTICS  11 


ANCMIiKK  of  recent  pronouncements  ma\  In- 
taken  as  indicative  of  the  mounting  interest  in  the 
problems  of  industrial  research,  particularly  the  supply 
and  training  of  scientific  personnel.  Industrial  re- 
search leaders  expressed  a  growing  concern  during  the 
war  over  the  depletion  in  the  ranks  of  scientific  stu- 
dents in  colleges  ;iiid  universities  and  emleav.  red  t<> 
insure  a  continuing  supply  of  graduates  in  science. 
They  were  unanimous  in  their  belief  that  serious  jmst- 
war  shortages  would  result  from  the  insufficient  num- 
ber of  science  students  at  study  during  the  war. 

What  was  predicted  has  now  come  true,  according  to 
William  S.  Richardson,  president  of  B.  F.  Goodrich 
Chemical  CO..  who  said  recently  that  the  demand  for 
chemists  and  chemical  engineers  far  exceeds  the  -u\>- 
ply.  He  called  it  regrettable  that  the  nation  has  al- 
lowed its  inventory  of  trained  minds  to  become 
depleted  in  a  world  of  scientific  competition,  and  de- 
clared that  more  money  must  be  spent  both  by  industry 
and  by  the  universities  for  investigations  into  pure  and 
fundamental  science. 

Speaking  recently  U-fore  the  Chemical  Kngineering 
Division  of  the  Society  for  the  Promotion  of  Kngi- 
neering Education.  Dr.  T.  H.  Chilton,  of  K.  I.  du  I'ont 
de  Nemours  and  Co.,  said  that  the  standard  university 
courses  provide  good,  usable  training  for  the  normal 
operations  of  the  chemical  industry  but  that  the  devel- 
o|Miient  of  new  products  and  processes  demand  not 
only  a  better  foundation  in  basic  science  than  standard 
curricula  offer  but  also  graduate  study  for  the  develop 
ment  of  "specialized  capabilities." 

These  indicate  some  of  the  problems  of  industrial 
research.  (  )f  the  remedial  action  that  is  being  taken, 
one  of  the  most  interesting  developments  to  provide 
mure  cajability  is  the  inauguration  of  a  plan  by  the 
Monsanto  Chemical  Co.  to  grant  academic  leaves  yearly 
to  four  of  its  employees  to  allow  them  to  return — at 
lull  salary — for  a  year  of  stud)  at  the  university  of 
their  choice.  Recipients  of  leaves  will  IK-  chosen  "on 
the  basis  of  meritorious  service  and  outstanding  per- 
formance m  scientific  work  at  any  time  and  any  loca- 
tion for  Monsanto,"  according  to  Dr.  Carroll  A. 
llochwalt.  director  of  central  research.  The  theory 
back  of  the  innovation  is  that  scientific  anil  tech- 
nological advances  result  from  fundamental  studies 
and  uninterrupted  speculation  on  such  studies 

\s  another  move  which  will  serve  to  strengthen  in- 
dustrial research,  the  Department  of  Commerce  has 
lished  an  <  >tti.  .•  of  technical  Services  to  consoli- 
date the  work  of  the  <  (Mice  of  the  Publication  Hoard. 
Technical  Industrial  Intelligence  ('.ranch,  and  the  Na- 
tional lii\i-n!ors  Council  The  old  services  will  U-  sup- 


plemented by  a  new  program  of  technical  aid  to  busi- 
ness and  industry.  Under  the  old  set-up  some  very 
notable  work  was  accomplished  (among  which — from 
the  standpoint  of  our  industry — the  collection  and  dis- 
semination of  information  on  the  results  of  German 
plastics  research  were  particularly  meritorious),  and 
the  new  division  should  be  of  even  greater  service. 

American  industry  as  a  whole  is  rapidly  gaining  an 
appreciation  of  the  value  of  research,  and  expansion 
in  research  facilities  has  been  launched  by  many  com- 
panies. In  fact,  industrial  research  has  grown  phe- 
nomenally in  recent  years.  According  to  Dr.  lloch- 
walt. in  1940  there  were  more  than  seven  times  as 
many  industrial  laboratories  as  in  1920,  and  he  pre- 
dicted 3500  laboratories  and  150,000  workers  by  1950. 
The  plastics  industry  must  get  into  the  swim  if  it  is  to 
maintain  its  competitive  place.  That  it  is  doing  so  is 
evidenced  by  the  Monsanto  graduate  study  plan,  the 
B.  F.  Goodrich  Chemical  Co.'s  planned  construction  of 
extensive  research  facilities,  and  other  progresshe 
actions  by  plastics  concerns.  These  are  good  omens 

for  the  future  of  the  industry. 

*     *     * 

A  RECENT  release  of  the  Tanners'  Council  of 
America  points  out  that  the  phrases  plastic  calf, 
plastic  leather,  and  plastic  patent  leather  are  not  per- 
missible in  advertising  handbags  and  other  articles 
made  to  imitate  or  resemble  leather.  Such  use  is  said 
to  conflict  with  rulings  of  the  Federal  Trade  Commis- 
sion which  limit  the  use  of  the  words  calf  or  leather 
to  products  made  from  the  hide  or  skin  of  an  animal. 

As  to  correct  usage,  it  is  pointed  out  that  the  terms 
black  plastic,  calf-finished  plastic,  and  leather-drained 
plastic  are  sufficiently  descriptive  to  meet  the  standards 
of  the  Federal  Trade  Commission  and  the  Better  I'.tisi- 
ness  Bureaus.  The  ideal  term,  however,  the  Tanners' 
Council  of  America  says,  is  simply  plastic. 

No  doubt  some  fabricators  and  distributors  have 
used  misleading  and  inaccurate  terminology  in  adver- 
tising plastics  products  which  look  like  leather.  We 
believe,  however,  that  the  most  common  term  in  use 
today  is  plastic  patent,  not  plastic  patent  leather  or  any 
of  the  other  objectionable  phrases 

There  is  no  argument  with  the  fact  that  the  plastics 
industry  should  choose  its  terms  with  care  so  as  not  to 
confuse  buyers  or  imply  that  its  materials  are  leather. 
lo  deliberately  name  a  plastics  product  so  that  the 
long-established  reputation  of  leather  and  leather  goods 
will  help  it  sell  seems  to  indicate  a  signal  lack  of  faith 
in  one's  own  product. 

Perhaps  a  committee  of  the  industry  should  IK'  named 
io  select  and  establish  a  whole  new  terminology.  i  M> 


12 


PL  AST I €9 


U  (.1ST    IHIfi 


How  Pills 
picked-up  Plastics 


A  Kurz-Kasch  idea  for  reducing  loading  time  back  in  1920, 
forming  material  into  pre-forms  or  "pills,"  quickly  came 
into  universal  use.  Without  it,  early  pre-heating  and  today's 
Heatronic  techniques  might  never  have  proved  practical. 


^OMEONE  always  benefits  first  from  every  new 

idea  in  plastic  molding — and  plastics  buyers  in  that  happy  position  usually 
count  their  gains  in  dollars  and  cents. 

As  this  series  of  ads  reveals,  Kurz-Kasch  customers  have  reaped  these 
benefits  for  many  years.  If  your  problem  is  compression  or  transfer  mold- 
ing— if  you  want  to  take  advantage  today  of  tomorrow's  bright  ideas — let 
us  tell  you  about  Kurz-Kasch's  molding  facilities.  Send  for  your  Free 
copy  of  our  booklet,  "A  Businessman's  Guide  to  the  Molding  of  Plastics." 


Kurz-Kasch 


For  Over  29  Years 

Planners  and  Molders  in  Plastics 


Kurz-Kasch,  Inc.,  1413  S.  Broadway,  Dayton  1,  Ohio.  Export  Offices:  89  Broad  Street,  New  York,  N.  Y. 
Branch  Sales  Offices:  New  York  •  Chicago  •  Detroit  •  Los  Angeles  •  Dallas  •  St.  Louis  •  Toronto,  Canada. 


AUGUST    1946 


PLASTiCS 


13 


,  .  .  RIGHT! 


BUT  IMPORTANT 

REFRIGERATO  R 

PARTS 


PLUG  CONNECTION  for 
Refrigerator  Thermostat  Con- 
trol and  Electric  Clock— 
molded  in  polystyrene,  mois- 
ture reststint  with  good  et«- 
incal  properties. 


IN  PLASTICS 


SOCKET  for  Refrigerator 
Light— molded  in  fleilble, 
rubber-like  vinyl  resin  plastic: 
long-lived  and  imperviotrs  to 
moisture  or  condensation. 


ef net  MACIIINII  01  nnmtiAi  fouir«i«t 


'fAr*tiM»MMM 


Inherent  capacity  to  stand  up  and  perform  under  the  worst 
conditions  of  moisture  and  temperature  is  absolutely  essential 
in  electrical  parts  like  these.  Frequent  servicing  costs  for  the 
appliance  buyer  eventually  cost  the  manufacturer  his  reputa- 
tion. So  these  jobs  came  to  Amos  . . .  and  Amos  did  them  right! 
Amos  quality  controls  ...  of  materials,  die-making,  molding, 
finishing  .  .  .  watch  over  the  product-reputation  of  Amos  cus- 
tomers, assuring  dependable  injection-molded  plastic  parts, 
large  or  small,  with  the  right  characteristics  to  meet  service 
conditions. 

Just  send  us  your  drawings  or  write  us  about  any  parts  prob- 
lem you  may  have.  We  may  already  know  the  answer— and 
Amos  engineers  have  a  way  of  finding  new  answers  when  the 
problem  demands  it. 
AMOS    MOLDED    PLASTICS,    EDINBURGH,    INDIANA 

DMtkxi  of  Amot-Thompion  Corporohon 
Orw  of  M>«  Moil  Modern  Ploffic  Molding  Honll  in  lh»  Induiiry 


14 


fl    %STM 


AUGUST  1946 


Gleaming  white  and  black 
plastics  piano  keys  which 
have  permanent  surface  lus- 
tre and  do  not  mar  or  chip, 
are  finding  wide  popularity 


'illiam. 

p/astics    Field  Editor 


THE  concert  pianist  need  no  longer  be  haunted  by  the 
fear  that  his  performance  will  be  marred  by  sticking 
piano  keys.  Caused  by  a  moisture-swollen  internal  mechan- 
ism, this  fault — a  long-time  bane  of  pianists  and  piano  man- 
ufacturers— can  now  be  eliminated  by  the  installation  of  a 
plastics  piano  action  developed  by  Pratt- Read  &  Co.,  of 
Ivoryton,  Conn.  First  publicly  exhibited  at  the  National 
Association  of  Music  Merchants  in  Chicago  the  week  of 
July  14,  the  new-type  action  is  said  to  be  the  greatest  inno- 
vation in  the  piano  industry  in  the  past  hundred  years  aside 
from  the  drop-action  introduced  about  ten  years  ago,  which 
permits  the  height  of  the  piano  to  be  adjusted. 

With  the  new  plastics  mechanism  for  striking  the  strings, 
when  a  player  hits  the  key,  he  can  be  sure  it  is  going  to 


sound.  Anyone  who  plays  the  piano,  whether  profession- 
ally or  at  home,  knows  how  exasperating  it  is  when  the  key 
sticks.  If  you're  playing  a  piece  like  the  Donkey  Serenade. 
in  which  the  note  C  is  repeated  five  times  running,  and 
also  occurs  frequently  in  later  measures,  the  performance 
is  completely  ruined  by  such  a  failure  of  the  action  mech 
anisni.  What  causes  this  failure  is  the  swelling  and  shrink- 
ing of  its  maple  wood  levers  due  to  moisture,  for  it  is  the 
action  which  the  striking  of  the  key  sets  into  motion  and 
which  in  turn  causes  the  hammer  to  strike  the  strings.  By 
making  these  levers  of  Ethocel,  which  is  virtually  non-mois- 
ture absorbing,  Pratt-Read  &  Co.,  an  institution  in  its  field, 
has  taken  a  revolutionary  step  to  stabilize  the  dimensions 
of  the  action,  and  the  piano  industry  is  reported  to  be  pro- 
foundly interested  in  it. 

From  the  viewpoint  of  the  end-user  of  plastics,  this  de- 
velopment is  also  of  great  interest  in  that  it  shows  what 
cooperation  he  can  expect  from  the  plastics  industry  when 
he  has  a  deserving  product.  Dow  Chemical  Co.  assisted 


AUGUST  1946 


PLASTICS 


15 


Because  of  low  moisture  absorption,  toughness,  and  dimensional  stability,  ethyl  cellulose  is   used   lor  action  part.     Damper 
blocks,  shown  ol  wood,  are  now  also  being  made  ol  ethyl   cellulose.     Right.   Pratt  Read   operator  on   the   production   line 


in  producing  the  right  formulation  of  Ethocel  ethyl  cellu- 
lose, and  General  Electric  Co.  Plastics  Division  and  Mack 
Molding  Co.  worked  out  the  molding  problems.  Nor  is 
that  all.  Further  along,  other  Pratt-Read  developments  for 
the  piano  besides  the  action  will  be  discussed,  and  in  these 
several  other  companies  have  made  their  contribution. 

Though  the  sole  function  of  the  action  is  to  mediate,  so 
to  speak,  between  the  key  and  the  hammer,  it  is  an  intricate 
mechanism,  as  the  accompanying  sketch  indicates.  In  effect, 
it  is  a  series  of  interlocking  levers— one  set  of  them  for 
each  of  the  88  notes — and  calls  for  wood  (now  plastic-  i. 
felt,  and  several  metal  part-,  in  its  construction.  Tin-  vital 
|«>ints  at  which  the  wood  swells  up  on  absorbing  moisture. 
thus  making  a  tight  joint,  or  shrinks  on  giving  up  moisture , 
causing  a  rattle,  arc  the  butt  flange,  whipprn  flange,  fly 
flange  ami  damjicr  flange  hinges.  Therefore,  all  of  these 
plus  the  catcher.  damper  head,  damper  block,  danipv 
<lani|M-r  lever  flange,  butt,  butt  flange,  regulating  rail 
button,  back  check,  fly  jack,  fly  jack  flange.  wliipjK-n  and 
whip  flange  have  been  converted  to  ethyl  cellulose.  The 
first  s|K-<-iinens  arc  ivory-colored.  Imt  they  can  IK-  produced 
in  any  ol'  the  brighter  hues  if  there  is  a  demand  for  them. 

Heiori  turning  to  plastics,  the  company  tried  some  light 
metals.  When  these  failed,  James  A.  <  iould.  president  of 
I'ratt-Head,  foresaw  that  plastics  would  provide  a  solution, 
and  the  study  of  various  tyjies  ol"  plastics  proceeded  under 
the  direction  of  (  harles  l-redcrick  Stem,  vice-president  in 
charge  of  engineering  and  lor  many  years  In-fore  the  war 
a  well-known  builder  of  Ins  own  pianos  in  Chicago.  No 
•  in  pla-tu  -.  Mr  Stem  knows  nil  there  is  to  know 


about  piano  actions,  and  hence  was  able  to  tell  the  material 
suppliers  and  molders  exactly  what  was  required  of  the 
parts. 

In  the  end,  ethyl  cellulose  was  chosen  because  of  its  low 
moisture  absorption,  its  toughness  and  durability,  its  dimen- 
sional stability,  and  its  easy  workability.  There  was  also 
the  question  of  tolerances.  With  the  wood  action  a  toler- 
ance of  only  .004"  was  allowed,  yet  it  is  hoped  that  the  use 
of  ethyl  cellulose  will  make  possible  an  even  smaller  figure. 
Other  factors  which  made  it  acceptable  it  shares  with  other 
plastic*.:  these  are  its  fine  appearance  and  the  possibility 
of  procuring  standard,  interchangeable,  uniform  parts  liy 
molding.  Other  plastics  are  superior  in  one  or  more  re- 
spects— polystyrene,  for  example,  having  practically  no 
water  absorption — but  ethyl  cellulose  was  chosen  for  its 
combination  of  properties. 

A  Major  Application 

With  each  unit  of  the  action  weighing  some  17  gin.  the 
total  amount  of  ethyl  cellulose  required  for  a  complete  ac- 
tion is  nearly  t> '.  Ib,  and  when  you  consider  that  the  piano 
industry  is  shooting  for  a  production  goal  of  350,000  in- 
struments a  year,  it  is  plain  that  this  is  one  of  the  major 
applications  for  injection  molding  so  far  developed.  Thr 
parts  are  produced  in  multiple  cavity  molds  varying  from 
If.  to  30  cavities. 

It  will  IM-  noted  that  lightness  is  not  mentioned  above  as 
one  of  the  pro|>erties  which  determined  the  choice  of  ma- 
terial, though  thermoplastics  as  a  class  |«iss<-ss  that  qual- 
ity.  and  reduction  in  the  weight  of  any  part  of  the  piano  is 


16 


I'l.  \STH   * 


\M.l  ST   1916 


Cellulose  nitrate,  more  durable  and  less  subject  to  cracking  than  ivory,  has  been  substituted  in  the  white  keys.     A 
method  of  folding  the  blank  at  a  right  angle  so  that  key  is  all  of  one  piece  simplifies  both  production  and  assembly 


noteworthy.  The  fact  is,  however,  that  the  maple  used  for 
the  action  is  slightly  lighter  than  ethyl  cellulose,  but  there 
are  other  factors  in  the  redesign  of  the  instrument  as  a 
whole  which  more  than  compensate  for  it. 

Nor  do  the  plastics  parts  cost  less,  at  the  present  initial 
stage,  though  it  is  expected  that  they  will  eventually.  Nev- 
ertheless, even  at  the  moment,  the  use  of  Ethoccl  will  per- 
mit the  piano  manufacturer  to  increase  his  production  be- 
cause the  parts  can  be  supplied  in  greater  number  than  they 
could  be  in  wood. 

Long-Term  Production 

Aside  from  this  immediate  convenience,  there  are  also 
long-term  production  considerations  favoring  plastics.  In 
the  first  place,  their  use  eliminates  a  number  of  parts.  The 
catcher  and  shank  of  the  butt  which  supports  the  hammer 
shank  can  be  molded  in  one  piece,  whereas  in  wood  they 
are  separate  pieces.  The  same  is  true  for  the  whippen 
and  the  fly  flange.  Second,  the  conversion  to  plastics  elim- 
inates the  necessity  of  having  a  big  lumber  inventory.  An 
important  saving  of  time  is  a  third  factor,  in  that  the  kiln 
drying  of  wood  to  be  used  in  the  piano  action  takes  10  days. 

A  fourth  operation  which  is  eliminated  for  a  simpler  one 
in  plastics  is  the  preparation  and  slicing  of  the  wood  mold- 
ing for  the  action  pieces,  and  the  subsequent  careful  finish- 
ing required.  Of  the  plastics  parts,  the  fly  jack,  the  back 
check  and  the  damper  lever  are  usable  as  they  come  out  of 
the  mold,  without  any  finishing  operation.  Only  the  whip- 
pen,  which  has  many  holes  in  divergent  planes,  requires 
finishing  operations. 


In  the  wood  mechanism,  when  the  back  check  wire  is 
pressed  in  and  driven  home  into  the  whippen,  the  part  very 
often  splits.  The  whippen  is  also  subject  to  cracking  when 
another  important  little  part,  the  spoon,  is  driven  into  it. 
In  both  cases,  the  use  of  tough  ethyl  cellulose  obviates 
this  loss. 

Reference  was  made  before  to  the  advantage  of  uniform- 
ity possessed  by  plastics  moldings.  This  is  not  merely  an 
academic  specification — a  desire  of  uniformity  for  uniform- 
ity's sake :  there  is  a  highly  important  practical  reason  for 
it.  In  the  wood  action,  what  piano  men  refer  to  as  the 
"walking"  of  the  Hammer  takes  place.  It  means  simply  that 
the  hammers  get  out  of  alignment,  and  then  do  not  strike 
the  strings  properly.  The  uniformity  of  the  plastics  pieces 
prevents  this. 

Similarly,  the  use  of  plastics  eliminates  looseness  in  the 
screSvs  attaching  the  action  parts  to  the  action  rail.  This 
unit,  formerly  made  of  wood,  is  now  being  produced  by  ' 
Pratt-Read  in  extruded  magnesium.  Since  it  is  drilled  for 
over  250  screw  holes,  there  were  that  many  chances  for 
cracks  to  be  sprung  by  temperature  and  humidity  action  on 
the  wood.  This  loosened  the  screws,  and  the  action  bar 
vibrated.  The  hammer  rail  also  has  been  converted  from 
wood  to  magnesium.  All  these  changes  make  possible 
greatly  increased  production,  for  the  piano  action  now  be- 
comes an  assembly  job  rather  than  the  cabinet  job  it  was. 

So  much  for  the  action.  The  company  has  also  adopted 
plastics  in  other  parts  of  the  piano.  Perhaps  half  a  dozen 
years  ago,  it  had  already  substituted  cellulose  nitrate  for 
ivory  in  the  white  key,  and  the  synthetic  material  is  re- 


AUGUST  1946 


17 


Various  plastic*  ior  us*  in  pianos  were  studied  under 
direction    ol    Charles    F.    Stein,    piano    action    innovator 

garded  as  more  durable  and  less  subject  to  cracking.  Pratt- 
Kea<l  has  now  made  an  ini|)<irtaiit  innovation  in  the  produc- 
tion nic-thiMl  for  this  key.  In  ivory,  there  are  three  pieces 
to  the  key  covering  (the  body  being  a  block  of  wood)  :  out- 
strip from  the  back  to  the  beginning  of  the  black  key.  a 
strip  covering  the  rest  of  the  top  and  projecting  slightly 
over  the  front  plane,  in  order  to  conceal  the  joint  made  with 
the  third  facing,  on  this  front  plane.  Originally,  the  cellu- 


iosi-  nitrate  key  was  blanked  out  in  two  piece-,  the  top  one 
still  projecting  above  the  frontal  piece.  Now  Pratt- Read 
ha*  perfected  a  method  of  folding  over  the  blank  at  a  right 
angle  and  the  key  is  all  of  one  piece.  With  this  improve- 
ment, both  production  and  assembly  are  simplified. 

The  next  obvious  move  was  to  mold  the  black  keys  instead 
of  cutting  them  out  of  ebony  wood.  The  right  plastics  would 
have  all  of  the  strength  required,  and  the  correct  molding 
process  would  insure  a  uniform  product.  The  Shaw  Insulator 
('nmpany.  the  Plastics  Division  of  deneral  Klectric.  and 
Consolidated  Molded  Products  I'orporation  worked  out  these 
problems  for  Pratt-Kead  &  Co.  The  answer  to  the  si-arch  for 
the  correct  material  turned  out  to  be  a  general  purpose 
phenolic.  This  material,  when  molded  by  the  pr<» 
worked  out  for  making  the  keys,  makes  possible  a  low  co»t 
product  which  will  not  mar  or  chip,  and  which  is  uniform  in 
dimensions  anil  in  surface  texture. 

Finally,  plastics  in  the  form  of  Tcgo  phenolic  resin  ap- 
]R-ars  as  the  bonding  agent  in  the  new  spruce  plywood 
sounding  board  developed  by  the  company.  The  plies,  cross- 
trained,  are  bonded  with  the  moisture-resistant  synthetic 
resin  adhesive,  and  with  vertical  instead  of  diagonal  ribs. 
The  sounding  board  has  a  permanent  crown  based  on  the 
principle  that  plywood  crowned  in  the  gluing  retains  the 
crown  because,  it  is  explained,  "any  radical  flattening  would 
IK-  impossible  without  a.  lateral  movement  of  the  plies  rela- 
tive to  each  other.  The  synthetic  adhesive  prevents  this 
movement."  The  plies  may  be  made  of  varying  thicknesses. 
according  to  the  piano  maker's  ideas  of  the  tonal  effects  to 
be  achieved.  "Never-split"  is  the  company's  name  for  the 
sounding  board. 

According  to  officials  of  the  company,  the  manufacture  of 
pianos  which  has  been  hampered  by  the  shortage  of  lumber 
will  now  have  unlimited  production  with  the  use  of  plastics 
materials. 

Nothing  in  the  piano  is  left  for  plastics  to  conquer  but 
the  case,  and  that,  tcx>,  is  on  the  way!  KM- 


Damper  Head 

Damper  Block 

Damper  Lever 

Damper  Lever  Flange 

Butt 

Butt  Flange 

Catcher 

Regulating  Rail  Button 


9. 
10. 
11. 
12. 
13. 
14. 
IS. 
16. 


14 


Back  Check 

Fly  lack 

Fly  lack  Flange 

Whippen 

Whip  Flange 

Sharp 

Top  Key  Covering 

Front  Key  Covering 


.15 


•  16 


18 


I'l.ASTICS 


AUGUST    1916 


Tenite  Counts 


sparent  Tenite  is  molded  into 
les  for  electric  counters  which 
d  the  number  of  pieces  of 
fruit  conveyed  along  a  mov- 
elt.  One  of  the  toughest  plas- 
lade,  Tenite  easily  withstands 
repeated  impact  it  receives 

the  fast-traveling  fruit;  and 
ise  of  its  exceptionally  light 
it,  only  slight  pressure  is  re- 
d  to  prevent  the  paddle  from 
cing  after  it  is  struck — thus 
ng  accurate  counting  and 
ding.  The  paddle  weighs  only 
ninres  complete  with  enclosed 
•ical  apparatus. 

nite  is  used  for  many  other 
jets  which  require  superior 
gth  and  durability  —  among 
,  saw  handles,  steering  wheels, 
for  terrazzo  flooring,  and 
•rcycle  starter  pedals.  These 
nolded  or  extruded  of  Tenite 
ninltnuin  of  time  and  often  at 
:ed  cost  to  the  manufacturer. 

r  complete  information  about 
properties  and  uses  of  Tenite, 
to  TENNESSEE  EASTMAN 
PORATION  (Subsidiary  of 
man  Kodak  Company), 
SPOUT,  TENNESSEE. 


i'irrns-fniinter  pttiMlp  mntffal  by-  Smithern  California  P/asfir*  Cn.  for  A-VW  \1nrhinfrv  Corp. 


TENITE  AN  EASTMAN  PLASTIC 


Injection  Mold  Design 

Part  IV.  Efficient  injection  depends  on  correct  venting;  parting 
line  location;  size,  shape  and  location  of  gates,  runners,  sprues 


Mold  maker  at  Cruvcr  Mfg.  Co.  applies  finishing  touches 
to  mold  for  a  toy  pistol  grip.  Note  the  Wild  West  motif 


B 


KM 


ONK  i if  i hi-   fundamental   problems  uf  producing  good 
inject  inn  molding*   i*  Retting  tin-  material   from  tin- 
machine  into  tin-  mold  cavity   MI  a-   to  avoid  as  much  as 
Mr  the  trundle  inherent  in  the  injection  molding  pro- 
cess.  These  include  ]**>r  surface  appearance,  shrink  marks. 
trap|M-d  air.  weld  marks,  and  unsightly  scars  where  the  gate 
ha-  hem  trimmed  off  the  casting. 

I  his  last-named  pruhlem  is  extremely  important  as  im- 
proper gating  can  cau-e  many  defect-  in  the  molded  piece-. 
and  may  even  lead  to  the  -crapping  of  an  cx]K-n-i\e  mold. 
The  straight  gate  I  l-'ig.  la  i  is  most  Common,  and  is 
MMtl  unless  moldings  are  designed  so  as  to  require  one  of 
the  Other  t%|»  -  I'.ecau-e  it  i-  the  easiest  to  trim  and  ' 
the  »malle-l  mark  »n  the  molding,  it  is  preferred. 


The  fan  type  gate  (Fig.  Ib)  is  used  on  pieces  like  boxes! 
or  covers  where  the  fan  effect  helps  to  spread  the  flow 
the  material  more  evenly  over  the  width  of  the  box,  and 
thus  lessens  the  danger  of  trapping  air  in  the  bottom  and 
of  excessive  flow  marks.  It  leaves  more  of  a  mark  on  the 
trimmed  piece  than  the  straight  gate,  anil  for  this  reason 
should  not  be  used  when  the  latter  will  do  the  job. 

Ring  gates  (Fig.  Ic)  are  preferred  on  deep  tulie-like 
cavities  such  as  pencil  barrels,  and  on  pipe  bits  where  a  long 
slender  core  is  required.  The  ring  gate  causes  the  material 
to  feed  more  or  less  evenly  down  the  cavity  on  all  si' 
the  pin,  thereby  eliminating  weld  marks  and  corresponding 
weakness  down  one  side  of  the  molded  piece,  and  relieving 
strain  on  the  core  pin  which  would  otherwise  result  from 
forcing  the  material  down  one  side  ahead  of  the  other. 

The  disc  gate  (Fig.  Id)  is  used  on  pieces  such  as  rings,! 
escutcheon  plates,  etc.  This  eliminates  welds  which  would! 
be  unavoidable  on  this  type  of  casting  if  it  were  gated  at! 
the  periphery.  This  gate  is  seldom  used. 

Single  cavity  molds  for  boxes,  discs  or  dish-shaped  pieces! 
are  often  gated  at  the  center  directly  by  the  sprue  (Fig.  le  >.| 
thus  eliminating  the  usual  runners  and  gates.  This  gives  J 
condition  of  material  flow  in  which  the  air  in  the  ca\  ny  isj 
pushed  ahead  of  the  material  toward  the  parting  line  where! 
it  can  escape,  thus  eliminating  venting  problems.  This  typr| 
of  gate  is  usually  rather  large  and  presents  a  ditViciiUJ 
trimming  problem.  It  also  usually  leaves  surface  irregu-l 
larities  on  the  other  side  directly  opposite  the  gate,  and! 
the-e  disadvantages  must  be  considered  before  its  use  isj 
decided  on. 

In  selecting  the  location  of  the  gate,  a  matter  of  trcnienJ 
dons  importance,  several  considerations  must  be  studied.  As 
molding  material  enters  the  empty  cavity,  the  air  that  was 
in  it  must  be  replaced  by  the  hot  material.  If  it  canned 
escape,  it  will  be  compressed  and  will  leave  a  void  or  al 
burned  spot  in  the  casting.  I'nless  some  allowance  is  made! 
for  venting  the  cavity,  good  moldings  cannot  be  produced! 
Location  of  the  gate  ha-  a  marked  effect  on  the  !<•. 
of  this  trapped  air.  For  example,  a  cup-shaped  article! 
gateil  at  the  rim  will  trap  air  near  the  bottom  of  the  cupj 
Therefore,  whenever  possible,  such  articles  should  be 
in  the  bottom,  so  that  the  air  will  IK-  driven  to  the  rifflj 
where  it  can  escajn'  along  the  parting  line  or  around  thq 
core.  Tin-  problem  of  venting  will  IK-  discu— ed  in  detail 
later. 

Location  of  the  gate  also  has  an  effect  on  the  strengtl 
of  the  molded  piece.  I-ong  thin  pieces  such  as  toothbru-U 
handles,  drafting  scales,  combs,  bezel  strips,  ,-tc..  should 
be  gated  at  one  end.  Care  should  lie  taken  not  to  gall 
directly  into  a  core  pin  as  this  will  split  the  stream  ol 
material  and  cause  a  weak  line  or  weld  where  it  coma 
together.  Combining  thick  and  thin  sections  in  the  --.in* 
piece  is  not  good  de-ign.  hut  if  it  cannot  be  avoided  th< 
gate  should  be  in  the  thick  section  to  minimi/e  -hrin 
marks,  dates  must  lie  trimmed  from  moldings,  a 
be  considered  in  locating  them  in  the  cavity.  They  shouli 
be  on  a  non  ap|>c.u.mce  -urfacr  whenever  possible,  hill 
this  cleaning  consideration  -hoiild  remain  secondary  t"  ma- 
terial flow. 

Sometimes  more  than  one  gate  is  u-ed  on  a  cavii- 
generally  this  is  not  good  practice  as  it  u-ually  doubl- 


20 


I'LASTiCS 


AUGIST    1941 


m 


A  New  Plastics  Injection  Press  for 
Easy-Fast-Profitable  Production 


FEATURES  OF  THE 


PRESS 


Watte  FOR 

FREE   FOLDER 

which  illustrates  and 
describes  theVan 
Dorn  Plastics  In- 
jection Press  and  its 
applications. 


•  1  OZ.  CAPACITY 

•  POWERED  FOR  PRODUCTION 

•  AUTOMATIC  PARTS  EJECTOR 

•  AUTOMATIC  TEMPERATURE  CONTROL 

•  LOW  COST 


2683    EAST    79TH    STREET 


CLEVELAND    4,     OHIO 


AUGUST    1946 


21 


o/= 


problems  as  welding  and  venting,  and   seldom  overcomes 
problems  which  cannot  be  licked  by  pr<>|K-r  use  of  a  single 

Kate- 
Alter  having  selected  the  proper  tvpe  of  gate  and  the 
best  location,  the  question  of  size  remains  to  IK-  settled. 
Of  two  schools  of  thought  on  this  matter,  one  Itelieve-  in 
•.mall  gates  and  high  injection  pressure,  and  the  other  in 
larger  gates  and  lower  injection  pressure.  The  latter  is 
probably  the  more  numerous  at  present.  The  main  dis 
advantage  of  large  gates  is  the  problem  of  trimming  the 
fasting.  Therefore  it  is  well  to  start  with  K''t<-s  o>nsnler- 
ably  smaller  than  may  be  necessary,  .since  it  is  an  easy  job 
to  open  them  up  when  the  mold  i-  tried  if  tins  pm\es 
necessary.  No  hard  and  fast  rule  fan  IK-  ^i\m  for  gate 
us  there  are  many  variables  \\hu-h  enter  into  the 
problem.  Some  shops  seem  to  be  able  to  ux-  much  smaller 
than  others  due  to  better  equipment  and  molding 
technique.  Si/e  of  gates  should  be  determined  by  trial  and 
error  methods  where  a  shop  has  not  had  the  long  expert 


ill  designing  molds  necessary  to  arrive  at  a  pro|HT 
judgment  in  advance. 

With  gates,  we  should  also  consider  the  problem  of 
and    rnnners,    for   these   play   as   important   a   part   in   the 
proper  tilling  of  the  cavity  as  the  gates  themselves.    I*arn 
gates  are  of  no  value  if  the  runners  which  feed  material  to 
them  are  inadequate. 

Runners  are  of  three  designs:    round,  half  roum: 
trapezoidal  <  l-'ig.  2). 

The  round  is  the  most  desirable  because  the  cross-sectioJ 
area  of  a  circle  is  greater  for  a  given  perimeter  than  any 
other  shape.  Hence  there  will  be  better  flow  and  lev. 
friction  drag  along  the  walls.  However,  this  design  re- 
quires that  the  nmner.s  be  cut  in  both  halves  of  the  die 
and  carefully  matched.  This  adds  to  the  cost  of  tl; 
ami  on  in. '-t  jobs  it  is  not  a  necessary  refinement. 

There  is  little  to  choose  between  the  half  round  and  the 
trapezoidal  runners.    Both  arc  common  practice.    Th< 
has  the  advantage  of  helping  to  hold  the  castings  on  the 


AUGUST  19411 


/=/<?     S 


PLUGS 


ejector  half  of  the  die  in  cases  where  trouble  from  this 
source  is  expected.  The  runners  should  have  a  high  polish, 
and  on  critical  jobs  they  should  be  polished  in  the  direction 
of  flow  of  the  material.  They  should  be  of  adequate  cross- 
section.  Main  runners  should  be  at  least  5/16"  in  diameter 
if  a  half  round  runner  is  used,  and  on  larger  shots  or  heavy 
section  moldings  they  should  be  even  larger. 

Runners  can  be  machined  into  either  half  of  the  die,  but 
usually  they  are  in  the  knockout  half  of  dies  using  ejector 
pins.  This  is  done  to  help  make  the  castings  stick  in  that 
half.  In  stripper  plate  dies  they  should  be  cut  in  the  injec- 
tion half  so  as  to  keep  the  stripper  plate  plain,  and  thus 
permit  the  castings  to  fall  free  of  the  die  as  the  stripper  plate 
comes  forward.  If  gates  are  cut  into  the  stripper  plate, 
they  may  prevent  this,  forcing  the  operator  to  pick  the 
casting  from  the  mold. 

Many  dies  with  adequate  gates  and  runners  are  unsatis- 
factory because  the  designer  has  carelessly  designed  the 
sprue  hole  too  small,  and  the  whole  material  flow  system 
is  bottle-necked.  A  good  sized  nozzle  3/16  to  y%"  in  diam- 
eter, depending  on  the  job,  should  be  used  in  the  machine, 
and  the  small  end  of  the  sprue  hole  should  be  about  1/32" 
larger  to  take  care  of  possible  misalignment  between  the 
sprue  bushing  and  the  nozzle  (Fig.  3). 

The  first  material  entering  the  mold  is  likely  to  be  colder 
than  the  rest.  Therefore  a  cold  slug  well  (Fig  3)  is  placed 
at  the  parting  line  end  of  the  sprue  to  receive  it.  This  well 
is  usually  undercut  to  serve  as  a  sprue  puller,  assuring 
the  removal  of  the  sprue  from  the  bushing  as  the  mold 
opens.  Additional  cold  slug  wells  are  often  allowed  at  the 
ends  of  the  main  runners  by  extending  them  well  past  the 
last  cross  runners. 

All  injection  molds  depend  on  proper  venting  for  their 
successful  operation.  Air  trapped  by  the  junction  of  two 
streams  of  material  is  compressed  and  causes  a  void  or  a 
burned  spot  on  the  casting  unless  some  allowance  is  made 
for  venting  the  die  at  that  point  so  that  it  may  escape.  In 
the  design  of  some  parts  no  problem  is  involved  on  this 
score.  On  flat  pieces  such  as  key  tags,  buttons,  etc.,  the 
material  pushes  the  air  ahead  of  it  to  the  parting  line  at 
the  side  of  the  cavity  opposite  the  gate,  and  the  air  escapes 
along  the  parting  line.  If  the  plates  fit  too  snugly  to  permit 
this  escape,  small  grooves  known  as  sprue  grooves  or  vent 
grooves  are  ground  along  the  surface  of  the  plates  from  the 
trouble  spots  to  the  outside  of  the  die.  The  air  escapes 
through  these. 

However,  on  some  shapes,  if  venting  is  not  carefully 
considered  before  the  mold  is  made,  there  will  be  a  great 
deal  of  trouble  before  the  mold  will  run  properly.  In  ex- 


So 


View  A-A 


.  6 


V/e*  B-B 


AUGUST  1946 


PLASTt CS 


23 


treme  cases,  the  mold  niay  have  to  be  discarded,  and  a 
new  <me  designed  along  different  lino-. 

The  problem  of  venting  i-  clo-cly  tied  in  with  loratimi 
',<•  and  selection  of  parting  line.  Before  beginning  a 
mold  layout  the  designer  should  -tuily  the  i>art  to  determine 
the  approximate  flow  of  material  which  will  result.  There 
mu-l  IK-  Mime  way  of  incorporating  a  vent  where  this 
material  flow  will  trap  air — otherwise  the  gate  or  parting 
line  will  have  to  be  redesigned  to  force  the  air  toward  a  spot 
from  which  it  can  escape. 

There  are  only  two  way-  to  vent  a  cavity.  The  first 
and  more  satisfactory  is  to  design  the  mold  in  such  a  way 
that  the  incoming  material  will  drive  the  air  to  the  parting 
line  or  the  open  end  of  a  cup-shaped  piece  -o  that  it  may 
•••  along  the  parting  line  or  around  the  core  (Fig.  4). 
This  construction  i.-  desirable  wherever  po--ihle  even  though 
coii-nlerable  extra  mold  cost  is  incurred. 

The  alternate  method  is  to  supply  a  means  of  venting  the 
cavity  by  incorporating  vent  plugs  i  I-'ig.  5)  or  by  a  built-up 
construction  (Fig.  61.  Here  again,  these  feature-  add  to 
the  cost  of  the  mold,  but  are  m-c<---ary  for  good  design  and 
trouble-free  molds.  Whenever  |>os-it)le  vent  plugs  should  be 
on  the  ejector  side  and  be  made  so  as  to  move  with  the 
ejector  action,  thereby  cleaning  themselves  of  material  and 
powder  during  each  cycle.  Otherwise  they  may  clog  up  and 
necr-sitate  a  shutdown  to  disassemble  the  mold  for  cleaning. 
Knockout  pins  often  serve  a-  vents  if  properly  located. 
Pin-  used  for  venting  should  have  grooves  or  flats  on  them 
giving  a!wmt  .0015"  clearance  for  the  escape  of  air. 

One  iif  the  first  considerations  in  laying  out  a  mold  is 
the  problem  of  selecting  the  proper  location  for  the  parting 
line  of  the  die.  The  parting  line  is  the  plane  at  which  the 
two  halves  of  the  die  separate.  Inasmuch  as  its  selection 
is  a  function  of  gating,  venting,  ejection,  finishing  after 
molding,  and  many  other  problems  already  covered,  its 
discussion  has  Ix-en  held  over  until  these  other  items  were 
treated. 


The  parting  line  is  a  function  of  ejection  localise  the 
cavity  mu-t  IK-  designed  so  that  there  are  no  undercut-  or 
reverse  tapers  sufficient  to  prevent  the  piece  from  being 
removed  from  the  cavity  and  punch.  The  parting  line  must 
be  located  to  eliminate  these  unless  side  pulls  or  loose 
are  provided  to  take  care  of  the  undercuts. 

It  is  a  function  of  venting  because  the  gate  is  normally 
located  somewhere  along  the  parting  line. 

It  is  the  function  of  finishing  after  molding,  for  the  gatl 
will  have  to  be  cleaned  off,  and  as  the  mold  wears,  objec- 
tionable flash  may  appear  at  the  parting  line. 

It  is  a  function  of  cavity  construction  as  the  mold  must 
l>e  designed  with  the  parting  line  located  to  make  machining 
or  bobbing  the  cavity  as  simple  as  possible.  Thi-  con-id- 
eration.  however,  should  be  secondary  to  operating  func- 
tions such  as  easy  ejection,  good  venting,  proper  gating. 

'  >n  many  pieces  the  location  of  the  parting  line  is  simple 
-nice  there  can  be  only  one  logical  place,  and  it  is  apparent. 
For  example,  the  bottle  cap  (Fig.  7a  i  would  IK-  parted  at 
the  largest  diameter,  and  the  pan  scraper  (Fig.  71i )  along 
one  edge  to  eliminate  the  necessity  of  matching  the  cavities 
in  both  halves. 

The  box  cover  (Fig.  7c)  would  be  parted  at  the  la- 
dimension,  i.  e.,  the  rim. 

(  iften,  however,  there  is  a  choice  of  parting  line  loca- 
tion, and  then  the  various  molding  problems  must  be  care- 
fully considered  before  the  selection  is  made. 

The  mold  for  the  cigarette  case  would  be  more  ea-\  to 
make  if  the  parting  line  were  designed  a-  shown  in  Fig. 
Sa,  but  venting  problems  require  that  for  trouble-free  pro- 
duction the  case  be  parted  along  the  side  (  Fig.  Sin.  and 
the  inside  IK-  formed  with  a  side  core  which  pulls  out  to  the 
side  as  the  mold  opens. 

The  molding  in  Fig.  8c  could  be  parted  in  either  loca- 
tion 1,  2,  or  3  without  changing  the  die  cost  very  much. 
From  the  standpoint  of  gate  removal,  the  parting  line  would 
(Continued  on  page  77) 


Srcrreuv  A-A 


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f*ff..tMTI  f\« 


\l  <;i  ST     1946 


WE'RE    NOT    SATISFIED 
WITH    A 


once  over 


*  i  in 

Ui  r 


Sometimes    even   an   "eagle   eye" 
doesn't  catch  certain  details.  Here 
at    General    Industries    we    know 
you'd  not  be  content  with  just  a   visual  inspec- 
tion of  finished  plastics  molded  pieces.  Instead, 
accurate  and  scientific  testing  devices  tell  us  that 
your  product  is  right  when  it  leaves  our  plant. 
Our  plastics  molding  combines  special  skills  and 
experience  with  the  most  modern  equipment  and 
mechanical  discoveries.  This  combination  assures 
high  quality... pay  s  dividends  in  increased  salability. 


No,  we're  not  satisfied  to  make  your  product 
just  good.  We  want  it  to  be  outstanding.  That's 
why  our  mold  makers  pay  special  attention 
to  accuracy  .  .  .  why  we've  added  heatronics 
to  our  plastics  molding  team  .  .  .  why  we  devote 
the  utmost  care  to  the  finishing  process  .  .  .  and 
why  our  final  inspections  are  done  with  precision 
instruments  and  meticulous  attention  to  details. 

Consult  us  on  your  plastics  molding  problems, 
without  obligation,  for  the  best  service  that 
science  and  human  ability  can  provide. 


GENERAL 
INDUSTRIES 


D  E  P  T.        P 


E  L  Y  R  I  A 


OHIO 


AUGUST    1946 


PLASTICS 


25 


Better  "Pick-Up 


Plastics  helps  new  vacuum  sweeper  increase  its  efficiency 


NOTEWORTHY  among  the  fields  in  which  applica- 
tion of  plastic-  i>  finding  ready  acceptance  is  that  of 
household  utilities.  There  the  characteristics  of  various 
plastics  lend  themselves  to  many  uses,  while  their  qualities 
of  light  weight,  easy  cleanability  and  general  eye-appeal  are 
attractive  to  the  homemaker. 

A  timely  example  of  the  increasing  use  of  plastics  in 
manufacture  of  household  items  is  found  in  the  Eleclrik- 
broom.  a  lightweight  vacuum  cleaner,  made  by  The  Regina 
('orji..  kahwav.  N.  J.  In  the  latest  model  of  this  cleaner 
(now  in  quantity  production)  a  number  of  plastics  parts 
have  been  added  to  those  contained  in  the  experimental 
model  first  shown  several  years  ago. 

<  >ne  of  these  additional  parts  is  the  Staticomb  attach- 
ment. This  is  said  to  be  a  valuable  addition  to  the  regular 
attachments,  which  consist  of  a  felt  dust  mop  and  a  bristle 
brush,  and  to  overcome  the  difficulty  generally  encoun- 
tered in  picking  up  particles  such  as  tine  thread--,  hair 
shed  by  cats  or  dogs,  lint,  and  similar  material.  The  Stati- 
comb. by  means  of  a  combination  of  electrostatic  attraction 
and  physical  engagement  by  its  teeth,  is  said  to  pick  up  such 
particles  quickly  and  easily,  simultaneously  parting  the  nap 
of  deep-pile  carpets  to  get  below  the  surface.  In  this  ap- 
plication. I.uinaritlt  (cellulose  acetate)  has  proved  entirely 
satisfactory.  It  is  pigmented  red,  and  injection  molded  in  ' 
four-cavity  molds. 

Another  important  improvement  made  possible  by  using 
plastics  is  in  the  no//!c  wheels,  which  were  originally  of 
rubU-r.  molded  around  a  brass  bearing  insert.  By  using 
l.umarith  instead  and  slightly  modifying  the  wheel  assem- 
bly, "a  substantial  saving  in  labor  and  material  was  ef- 
fected." according  to  C.  N.  Smith,  Jr.,  Regina's  production 
engineer.  One  of  the  advantages  listed  for  the  acetate  wheel 
is  that  if.  through  neglect  of  cleaning,  it  becomes  jammed 
in  the  housing,  it  will  still  slide  smoothly  over  carpets, 
whereas  the  rubber  wheel  would  drag,  eventually  flatten. 
and  perhaps  damage  the  floor  covering.  In  addition,  it  has 
been  found  that  the  acetate  wheel  leaves  no  marks  on  rugs, 
rs.  or  upholstery,  and  tests  have  indicated  its  longevity. 


Dtsaesembled  »lew  ol  the  plastic*  part*  ol  Improved 
•weeper,  which  help  accomplish  better  cleaning  (ob 

26 


Easily  removed  for  emptying  after  each  use.  convenient 
dirt   cup  is  one  of  special   features  of   "Electrikbroom" 


Another  change  made  by  the  company  was  in  the  handle 
wheel  of  the  cleaner,  although  this  change  was  in  the  plas- 
tics material  used.    The  handle  wheel  is  dropped  from  in 
position  on  the  upper  part  of  the  handle  to  make  a  three- [ 
point  roller  contact  with  the  floor  when  the  nozzle  is  reJ 
placed  by  the  attachment  hose,  with  its  two  swivel  casters. 
This  permits  the  Klectrikbroom  to  be  run  horizontally.  :.i 
the  manner  of  a  tank-ty|>e  cleaner.    The  part  was  formerly 
machined  from  a  cast  phenolic.     It,  too,  is  now  being  in-' 
iei-tion  molded  of  l.nmarillt  in  a  combination  mold  having 
four  cavities  for  the  handle  wheel  and  eight  for  the  no//Ie 
wheel. 

This   material   is  also   l>eing   used   for   the  locking  cam  j 
handle   in  the  new    models.      It   is  larger  than  the  original 
handle,  which  was  of  cast  phenolic.    The  increased  si/re  is 
not  due  to  functional  requirement,  but  to  the  fact  that  a  can] 
o|K-ner    made    by    the   company    utili/es    the   same   sort   of 
handle,  and  since  the  can  opener  is  being  produced  in  lar 
quantities,  an  economy  was  effected  by  adapting  the  handle 
to  both  devices  and  injection  molding  it  in  20-cavity  molds. 

The  plastics  application  in  the  original  model  of  lilcftrik- 
broom  which  remains  unchanged  is  a-,  sound  as  ever.  This 
is  its  dirt  cup  which  is  emptied  after  each  use,  thereby 
eliminating  an  accumulation  of  dirt  as  in  the  conventional 
\ariium  cle.mer  I>ag.  The  cup  is  still  being  compression 
molded  of  black  phenol  formaldehyde,  in  a  two-cavity  mold, 
inasmuch  as  the  material  and  method  have  been  found 
eminently  satisfactory  for  this  application. 


K  Ml 


I'l.ASTtCS 


AUGUST  194fi 


[•^••[[[•••^••••[•••^ 

ELECTRONIC   SEALING    by  THERMATRON 

w 

MAKES  PRODUCTS   LIKE  THESE   POSSIBLE 

Sealed  by  GEMLOID  on  the 


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4» 


The  necessity  of  producing  a  great 
volume  of  thermoplastic  products  for  the 
armed  forces  convinced  the  Gemlaid 
Corporation  that  traditional  methods  of  sealing 
would  be  cumbersome  and  inadequate. 
The  vision  evidenced  by  Gemloid  in  becoming  the 
pioneers  in  the  use  of  THERMATRON 
Dielectric  Electronic  Equipment  for  the  sealing  of 
plastics  resulted  in  vastly  increased 
production,  accompanied  by  slashed  operating  costs. 


During  the  war  the  Gemloid  Corporation  used 
the  THERMATRON  to  seal  millions  of  vital  plastic 
desalter  bags  essential  to  the  armed  forces  for  the 
conversion  of  salt  water  to  drinking  water.  Since  then, 
Gemloid  has  employed  its  battery  of  THERMATRONS  for 
the  sealing  of  thousands  of  plastic  pillows,  mattress 
covers,  aprons,  and  a  variety  of  other  plastic  products. 
Despite  continuous  twenty-four  hour  use  for  more  than 
two  years,  Gemloid's  THERMATRON  equipment  is  still 
operating  with  maximum  efficiency  at  minimum 
maintenance  cost. 

THERMATRON  Dielectric  Heaters,  completely  self-contained 
and  ready  to  use,  are  also  available  to  molders  for 
preheating  rubber  and  plastic  preforms,  for 
laboratory  wood  gluing,  and  general  purpose  use. 

Write  today  without  obligation  for 
your  copy  of  "Electronic  Heating  With  the 
JHERMATRON",  a  comprehensive, 
practical  guide  to  the  application  of 
electronic  dielectric  heating. 
Address  Dept.  T-S 


G\w 


•Reg.  Trade  Mark 


THERMATRON  DIVISION 

RADIO    RECEPTOR    COMPANY,   IF 

•f^,\  Since  7922  in  Radio  and  E/ecfronics 

dSfffl    251   WEST  19th  STREET   •   NEW  YORK  11,  IV.  Y. 

*$*£$/      MID-WEST     SALES:     ZEPHYR     ELECTRON/CS,     CHICAGO,    ILL. 


AUGUST  1946 


Cellulose  acetate  U  used  in  a  wide  variety  oi  inexpensive  kitchen  utensils  which  have  always  been 
popular  with  the  housewife  who  enjoys  their  colorfulness,  light  weight,  and  good  wearing  qualities 


Its  excellent  molding  properties  and  uniformity  of  texture 
make  "Tenite"  a  desirable  material  for  men's  garter  clasps 


Know  Your 


W.   O. 


Pl«itic«   Marketing   Section,    HtrcuUt   Powder  Co. 


PiiKNoNus  \i.  is  tlic  word  for  the  growth  in  the  use  of 
cellulose  acetate  plastics  since  1929.  This  was  tin- 
year  in  which  the  molding  compound  was  first  marketed — 
sheets,  rods,  and  tubes  having  been  available  in  the  two 
years  preceding.  It  was  soon  evident  that  tin-  thermo 
]il:isticily.  heat  and  light  stability,  toughness,  strength,  re- 
siliency, ami  high  lustre  iif  the  new  compound  made  it  a 
first-class  inject  inn  molding  powder,  and  its  popularity  has 
grown  steadily.  Today  cellulose  acetate  materials  constitute 
tlie  largest  single  group  of  injection  moldings  sold  in  Un- 
American  market.  An  influential  factor  bringing  about 
this  popularity  was  the  development  of  the  injection  mold- 
ing machine,  which  greatly  increased  the  speed  of  production 
for  relatively  small  articles  anil  also  made  |x>ssil>le  the 
production  of  single  large  units. 

A  development   exjK-cted   to  broaden  further   the  applica 
lions  of  acetates  c.ime  alioiit  through  the  war-time  emphasis 


M  (it  ST 


"Tenite"  shake  bottles  for  Kelly  pool  and  pocket  billiards 
are  very  durable,  withstand  hard  knocks  and  rough  usage 


Acetate  containers  are  preferable  to  glass  in  many  instan- 
ces because  they  will  not  chip,  are  clear  and  economical 


Attractive,     durable,     pleasant-to-touch     dresser     sets     are 
molded  by  the  Gemloid  Corp.  of  Hercules  cellulose  acetate 


ACETATES 


Toughness,  strength,  clarity,  and  general  workability 
promise  a  wide  variety  of  increased  industrial  applications 


on  performance  rather  than  on  beauty  and  glamour.  This 
emphasis  on  function  led  to  the  development  of  high  acetyl 
acetate  to  a  much  greater  extent  than  ever  before.  The 
degree  of  acetylation  is  a  measure  of  the  extent  to  which 
acetic  acid  combines  with  the  OH  groups  in  cotton  cellulose. 
Since  there  are  three  OH  groups  in  cotton  cellulose,  the 
acetylating  reaction  can  be  carried  out  only  as  far  as  the 
point  at  which  the  three  OH  groups  are  replaced. 

Thus  the  high  acetyl,  or  triacetate,  grade  is  obtained  when 
about  2.8  to  three  OH  groups  have  been  replaced,  represent- 
ing a  combined  acetic  acid  content  of  about  60.6  to  62.5%. 

Just  a  few  years  ago  high  acetyl  acetate  was  considered 
of  no  industrial  value  because  of  its  relative  insolubility  and 
high  softening  point,  which  made  it  hard  to  handle  both  in 
production  and  application.  Today,  however,  because  of 
the  rapid  pace  at  which  technical  developments  have  moved, 
a  large  percentage  of  all  the  cellulose  acetate  being  used  is 


of  the  high  acetyl  type.  The  reasons  for  this  swing  are  its 
higher  water  resistance  and  the  improved  dimensional  stabil- 
ity of  plastics  articles  made  from  it. 

The  cellulose  acetate  preferred  several  years  ago  had  a 
fairly  low  acetic  acid  content.  It  was  preferred  because  it 
is  easy  to  mold  by  injection,  production  is  rapid,  and  mold- 
ing temperatures  are  not  too  critical — in  short,  because  there 
isn't  much  chance  to  go  wrong.  But  this  type,  on  prolonged 
exposure  to  water  or  high  humidity,  will  absorb  enough 
moisture  to  cause  slight  swelling  and,  in  some  places, 
warping. 

Now,  the  careful  formulation  of  high  acetyl  cellulose 
acetate  has  made  it  practical.  To  mold  it,  high  molding 
temperatures  are  necessary  and  rather  wide  gates  are  desir- 
able. There  has  also  been  a  trend  toward  formulae  designed 
to  give  greater  rigidity  and  hardness. 

The  wide  range  of  approved  military  uses  for  acetate — 


AUGUST    1946 


PLASTICS 


29 


"Lumarith"  tile  handbags  have  long  been  favorites  ol  discrim- 
inating   women.     Below,    tiles   as    they    come    from   the    mold 

much  "I  it  Hi  tin-  high  acetyl  type — during  the  war  suggests 
many  new  civilian  applications.  Tin-  largest  amounts  of 
acetate  were  Used,  in  the  order  named,  in  the  rocket  pro- 
gram: nozzle  closures;  electrical  connections  for  the  rocket 
program:  toothbrushes  and  other  lirtishes :  squadron  equip- 
ment cases;  flashlights  and  flashlight  lenses:  leak  cletectors : 
optical  frames;  goggle  lenses;  soap  boxes;  and  control 
knobs  for  armed  transport  vehicles. 

\cetate  was  also  approved  by  the  armed  services  for  Mich 
ti^cs  as  ra/or  |>arts  and  razor  boxes,  waterproof  cigarette 
mechanical  |H-ncils  and  |iencil  parts,  hardware  and 
plumbing  supplies,  paint  brush  bristles,  musical  instrument 
|>arts.  nani'-plates.  toilet  elbows,  trays,  aircraft  parts  and 
instruments.  wingtip  lights,  safety  shields,  fruit  juicers. 
\cst-|>ocket  si/e  oil  cans,  lace  masks,  windows,  machine 
guards,  dice,  combs,  fuel  «ight  gauges,  sunglasses,  anil  screw 
driver  handles. 

I  Yllulose  acetate  molding  compounds  are  made  from  cellu- 


•urfoced   and    modern   In   design.    "Tenite"   mirror   stand 
le    attractive    addition    to    dressing    table    or    bathroom    shell 


:cetate  tlake.  mixed  with  plasticizers.  pigments,  und 
other  ingredients.  Since  the  tlake  is  the  basic  component, 
its  manufacture  is  worth  describing,  as  carried  out  by  the 
Hercules  I 'owder  Company.  To  begin  With,  bales  of  chemi- 
cal cotton  pulp  are  pulled  apart  mechanically,  after  which 
the  Huffed  fiber  i*  given  a  preliminary  treatment  with  acetic 
acid  in  special  tanks.  The  wet  mass  is  then  transfer] 
large  acetylator-,  to  which  measured  proportions  of  acetic 
anhydride,  catalyst,  and  solvent  are  added.  With  the  aid  of 
mechanical  agitation  and  tcm|xrature  control,  the  acetyla- 
ting  reaction  converts  the  fibrous  mass  to  a  clear,  liber-tree 
do|n-  solution  of  cellulose  triacetate. 

After  several  more  steps  the  purified  ester  is  de-watered, 
dried,  and  packed  in  the  various  forms  required  by  the 
trade.  Throughout  the  process  the  materials  are  handled 
in  an  entirely  closed  system  all  the  way  from  the 
of  chemical  cotton  pulp  to  the  finished  packages  of  cellulose 
acetate  flake.  This  closed  system,  together  with  large-scale 
processing,  insures  freedom  from  all  outside  contamination 
and  the  continuous  production  of  large,  uniform  t|iiantities 
of  material  within  close  specification  limits. 

Although  the  name  "cellulose  acetate"  is  nearly  :i' 
referred  to  as  a  specific  term,  there  actually  are  mam 
of  the  material.      Difference   in  types,  which  provid* 
proper  selection  for  specific  uses,  is  based  on  viscosity  of 
cellulose  acetate  flake  and  the  degree  of  acetylation,  that 
is.  the  extent  of  the  reaction,  of  cellulose  with  acetic  acid. 
The  degree  of  acetylation  is  usually  expressed  in  perci 
of  acetic  acid.    Each  of  the  general  types  is  furnished  in 
three  viscosities — high,  low,  and  medium. 

While  Hercules,  for  example,  produces  five  staple  types 
of  cellulose  acetate  tlake.  it  can  also  furnish  "tailor-made" 
types  to  meet  particular  specifications  in  acetylation,  v 
ity,  solubility,  color,  clarity,  uniformity,  haze,  and  granu- 
larity. 

Molding  Powders 

Cellulose  acetate  molding  powders  have  two  main  com- 
ponents— cellulose  acetate  flake  and  plasticizer.  However. 
numerous  variations  are  possible  U-cause  of  the  different 
kinds  of  flake  and  plasticizers  available.  For  example,  it  is 
possible  to  use  cellulose  acetate  of  a  low  viscosity  to  p  '  •"> 
low  flow  temperature  with  little  effect  on  strength.  It  is 
also  possible  to  get  goal  mottled  effects  without  using  an 
-ively  hard  formula  for  the  mottling  component  by 
using  a  high-viscosity  cellulose  acetate.  Water-resistance. 
also,  may  be  modified  by  proper  choice  of  acetate  flake  and 
plasticizer.  As  pointed  out  above,  the  moisture  resistance 
of  cellulose  acetate  increases  with  the  degree  of  acetylation. 

Moisture-  and  heat-resistant  grades  are  usually  based 
upon  acetate  of  56  or  58fr  combined  acetic  acid  content. 
There  is  no  appreciable  change  in  percentage  of  combined 
acetic  acid  during  the  molding  pro- 

I'lastici/ers  have  several  functions.  They  make  possible 
lower  molding  temperature  and  reduce  |>ossiblc  adverse 
effects  on  color.  They  aid  in  colloiding  the  mix  into  a 
homogeneous  mass.  And  they  help  bring  out  the  most 
desirable  physical  properties.  Mich  as  toughness,  hardness. 
flexibility,  dimensional  stability,  and  resistance  to  water. 
Maine,  oils.  fats.  Creases,  and  temperature  changes. 

Since  tin  one  plasticizer  permits  all  the  desired  prop< 
to  be  attained,  mixed  plastici/ers  are  usually  used.     Such 
mixes  usually  contain  one  or  more  "toughening"  plasttCUCCTI 
— such  as  dimethyl  or  dicthyl  phthalate,  triacetin,  tripro- 
pionin.   or   triethyl   citrate — plus  a  hardening   plasti 
which  may  also  serve  another  function  besides  contributing 
to  the  hardness  ,,i  the  molded  article.     For  example,  tri- 
phenyl  phosphate,  a  hardening  plasticizer,  also  acts  as  a 
flame-retarding  agent. 

Such  properties  of  the  molding  powder  as  fluidity  when 
hot,  setting  temperatures,  shrinkage  on  cooling,  granulation 


Pl.ASTtl-S 


AUGUST  1946 


This  kind  of  arithmetic 

may  put  Johnny  through  college 


Here's  how  it  works  out: 

$3  put  into  U.  S.  Savings  Bonds  today  will 

bring  back  $4  in  10  years. 

Another  $3  will  bring  back  another  $4. 

So  it's  quite  right  to  figure  that  3  plus  3  equals 
8  ...  or  30  plus  30  equals  80  ...  or  300  plus 
300  equals  800! 

It  will . . .  in  U.  S.  Savings  Bonds.  And  those 


bonds  may  very  well  be  the  means  of  helping 
you  educate  your  children  as  you'd  like  to  have 
them  educated. 

So  keep  on  buying  Savings  Bonds — available 
at  banks  and  post  offices.  Or  the  way  that  mil- 
lions have  found  easiest  and  surest — through 
Payroll  Savings.  Hold  on  to  all  you've  bought. 

You'll  be  mighty  glad  you  did  ...  10  years 
from  now! 


$AV£  THE  EASY  WAY...  "BUY  YOUR  WNDS  THROUGH  PAYROLL  SAVINGS 


Contributed  by  this  magazine  in  cooperation 
with  the  Magazine  Publishers  of  America  as  a  public  service 


AUGUST  1946 


FK.A8T1C8 


aid  form,  water  ah-orption.  and  flow  temperature  are 
all  -uhject  to  control  by  change*  in  formulation. 

A  No  -ubject  to  control  are  the  following  properti< 
the  molded  piect  :  toughne—.  hardne— .  cold  flow,  shock 
i net-  at  low  and  high  temperature*,  color,  and  re-i-t- 
ance to  tro|>ic:il  humidity.  In  fact,  even  finishing  and 
a— embling  technique-  may  1«-  varied,  depending  on  powder 
composition. 

Pre-ent-day  molding  pouder-  are  n-ually  classified  by 
iiK-an*  of  tht-ir  flow  temperature.  The  flow  temperature 
may  IK-  rai*ed  liy  dccrea-ing  the  amount  of  the  pla*ticizer 
in  the  formula,  by  varying  the  plasticizcr,  or  by  using  a 
higher  vi-co-iiy-lype  cellulose  acetate  flake. 

Product*  mcilded  from  any  of  the  early  cellulose  acetate 
molding  powder-  po— e— ed  fairly  low  flow  tenij>erature-. 
However,  iluring  the  war  military  requirements  demanded 
perfect  pi-rforinance  at  160°  to  "l80°  F.  To  meet  tllc-c 
specilication-  acetate  -upplier-  developed,  and  molders  found 
out  how  to  mold,  the  harder,  high  flow  temperature  ma- 
terial-. 

Acetate  Laminates 

Another  recent  development  i-  the  manufacture  of  ccllu- 
lo-e  acetate  laminate-.  Compo-ed  of  cellulose  acetate  bind- 
er- and  fabric  or  paper  tiller-,  the-e  laminate-  have  valuable 
propertie-.  (larticnlarly  a  high  degree  of  shock  resistance. 
My  -electing  -pecial  textile-  for  lamination,  the  impact 
-trength  a-  compareil  to  molded  cellulo-e  ]ila-tic-  can  \tc 
tripled  and  -ometime-  i|uadrupled. 

The  ea-e  of  fabrication  of  the  laminate-,  by  heat-forming 
and  dcejxlraw  ing  from  flat  -heel-,  without  complex  or  ex- 
peii-ive  ei|iiipment.  open-  up  many  possibilitie-.  The  range 
of  u-able  color-  i-  unlimited.  In  addition,  excellent  electri- 
cal characteri-tic-  and  Sow-temperature  flexibility  are  ob- 
tainable by  -electing  the  pro|>er  type  of  acetate  a-  a  binder. 

The  light  weight  of  the  acetate  laminate-  i-  another  factor 
which,  combined  with  -hock  re-i-tance.  toughne— .  colora- 
bility  and  electrical  characteristic-,  -tlggc-t-  their  use  a- 
hou-ing-  for  electrical  equipment,  including  refrigerator-, 
and  for  luggage  and  decorativi-  table  top-. 

A  -econd  type  of  laminating,  n-ing  cellnlo-e  acetate  dope-, 
i-  called  the  wet  proce--.  In  general,  the  method  i-  to  coat 
cloth  with  a  cellu!o-e  acetate  C|O|K-  ami  then  allow  it  to  dry 


with  natural  -hrinkage.  The  coated  cloth  i-  then  painted 
with  more  of  the  dope  and.  while  still  pliable,  i-  formed  by 
-tretching  it  to  lit  the  compound  curve-  of  a  form  iu-i  a- 
rnhUeri/ed  cloth  i-  manipulated.  Succe--ive  layer-  of  cloth 
and  dope  are  laid  up  to  get  the  de-ired  thickne— .  When 
laid  up  wet.  the  laminate  can  IK-  fitted  to  any  -hape  dc-ired 
and  will  dry  to  thi-  sha|x-.  Thi-  method  i-  useful  where 
lough,  vibration-ab-orbing  large  article-  are  wanted  for 
which  it  would  be  uneconomical  or  otherwi-e  unde-irable 
to  build  metal-ty|K'  mold-.  Such  items  a-  boat-,  lamp-,  and 
artificial  limbs  have  IH-CII  made  by  thi-  prof- 
it! -olution  form,  cellulo-e  acetate  i-  used  in  producing 
rayon,  foil,  and  tilm.  as  well  a-  -jK-cial  lacquer-,  paint 
remover-,  and  mi-cellaneous  product-. 

General  Properties 

In  any  product  made  from  cellulo-e  acetate,  the  ('ill-land- 
ing characteristic  i-  toughne-- — the  ability  to  with-land 
-hock  without  breaking.  Toughne—  depend*  to  a  large  ex- 
lent  ti|Min  the  vi-co-ity  of  the  ester:  the  higher  the  via 
of  the  acetate,  the  tougher  i-  the  product  made  from  it  This 
property  i-  also  influenced  by  the  kind  and  amount  of 
pla-tici/er  a-  well  a-  ihe  degree  of  acetylation. 

Another  characteri-tic  of  articles  made  from  cellnlo-e 
acetate  i-  good  clarity.  In  a  gixxl  quality  (lake,  there  i- 
little  yellow,  both  initially  and  after  molding,  -o  thai  xerv 
little  dye  i-  needed  to  give  il  a  neutral  color.  A  -olid  color 
can  be  attained  if  dye  i-  added  iK-vond  the  neutral  point. 
The  unu-ually  -mall  amount  of  color  in  the  acetate  ha-  led 
to  it-  wide  n-e  in  len-e-  and  aircraft  transparencies.  Clear 
pla-tic-  article-  of  gla— -like  tran-pareticy  can  IK-  made  by 
adding  minute  amounts  of  the  proper  neutralizing  dye  to 
the  acetate. 

Product-,  made  of  cellulose  acetate  wear  well.  In  the 
automotive  field,  for  years  cellulo-e  acetate  ha-  Ix-en  the 
preferred  material  for  finely  fini-hed  durable  knob-  and 
fitting-.  In  aircraft,  recent  experience  has  empha-i/ed  that 
lough,  rc-ilicnt  cellulose  acetate  Iran-parent  .-heeling  re-i-t- 
abra-ion  from  wind-lM>rne  -and  lietter  than  harder,  more 
brittle  material-. 

Another   -trong  point   in  favor  of  cellnlo-e  acetate   i-   il- 
noteworthy  re-i-tance  to  discoloration  by  sunlight.  Although 
(Continued  on  page  73) 


full  Hep  in  th»  manulactur*  of  ac«lal«  it  to  l««d  chemical  cotton  Into  the  "bale  breaker"    Right.  Hei- 
cul«*  Powder  Co.  le«U  acetate  itripe  lor  resistance  to  discoloration  by  exposing  them  to  ultraviolet  light 


I'l.  .\STI4  S 


\l   (.1   SI      1!UH 


PLASTICS...  FOR  THE  CREAM  IN  YOUR  COFFEE 


IMF.  HEART  of  a  cream  separator,  which  works  by  centrifugal 
force,  is  a  set  of  23  or  more  whirling  discs.  They  must  be 
odorless  .  .  .  tasteless  .  .  .  easy  to  remove  and  clean. 

The  problem  of  making  cream  separator  discs  out  of  plastics 
—the  first  ever  used  was  solved  by  General  Electric's  com- 
/)/<'/<•  plastics  service  for  the  Galloway  Co.,  Inc.,  Waterloo,  Iowa. 

Laminating  and  molding  gives  the  plastics  disc  the  required 
mechanical  strength,  a  high  finish,  and  above  all,  a  shape  that 
can't  be  distorted  to  cause  vibration  in  the  cream  separator. 
And  plastics,  of  course,  give  important 
chemical  resistance  to  lactic  acid  and 
the  corrosive  cleaning  solutions  used 
by  dairymen  with  such  frequency. 

Perhaps  you,  too,  could  use  the 
chemical  resistance  of  a  plastic  part 
to  good  advantage  in  your  product. 
Bring  this,  or  any  other  plastics  prob- 
lem, to  General  Electric— the  world's 
largest  manufacturer  of  finished  plas- 


tics products.  Write  to  the  Plastics  Divisions,  Chemical  De- 
partment, General  Electric  Co.,  I  Plastics  Ave.,  Pittsfield,  Mass. 
Ask  for  the  new  illustrated  booklet,  "What  Are  Plastics?" 

G-E  Complete  Service  —  Everything  in  Plastics 

Backed  by  52  years  of  experience.  We've  been  designing  and  manu- 
facturing plastics  products  ever  since  1894.  G-E  Research  works  continu- 
ally lo  develop  new  materials,  new  processes,  new  applications. 

No.  1  Plastics  Avenue  —complete  plastics  service— engineering,  design 
and  mold-making.  Our  own  industrial  de- 
signers and  engineers,  working  together,  cre- 
ate plastics  parts  that  are  both  scientifically 
sound  and  good-looking.  Our  own  toolrooms 
are  manned  by  skilled  craftsmen — average 
precision  mold  experience,  12  years. 

All  types  of  plastics.  Facilities  for  com- 
pression, injection,  transfer  and  cold  molding 
.  .  .  for  both  high  and  low  pressure  laminat- 
ing ...  for  fabricating.  And  G-E  Quality 
Control — a  byword  in  industry — means  as 
many  as  160  inspections  and  analyses  for  a 
single  plastic  part. 


GENERAL  ttb  ELECTRIC 

C0«*-*1* 

General  Electric  plastics  factories  are  located  in  Fort  Wavne,  hid.,  Meriden,  Conn.,  Scranton,  Pa.,  Taunton,  West  Lynn,  and  Pittsfield,  Mass. 

AUGUST    1946  PLASTMCS  33 


tm- 


Incendiary  bcmbt  loosed  during  the  air  pounding  of  German   factories  at   times  complicated   investigational   problems 

An  Interpretative  Survey  of 

German  Plastics  Fabrication 


B      W.    C. 


y 


in 


Mjneger.    Pleitici    Development    Division 
The  Dow  Chtmicsl  Company 

THK  (icrni.iiis  were  act  i  vi-  in  the  held  of  plastics  foam 
production.  The  types  of  plastics  mi  which  these  foam- 
were  based  inclti'lcil  urea  formaldehyde,  poly  vinyl  chloride, 
the  complex  polyurethancs,  and  to  some  extent  polystyrene 
and  cellulose  acetate.  The  processes  used  involved  (  1  )  the 
whipping  of  air  into  a  viscous  mixture  which  later  solidi- 
fied; (2)  the  inclusion  of  a  chemical  or  group  of  chemicals 
which  upon  heating  released  a  gas  and  thus  foamed  the 
plastics;  ami  <  .'  i  the  process  of  direct  combinations  of 
chemicals  which  during  the  reaction  formed  solidified  plas- 
tics materials  and  released  either  carbon  dioxide  or  hydro- 
gen, or  both,  to  give  a  foamed  product.  The  foams  thus 
produced  were  used  in  low-temperature  heat  insulation  .m.l 
buoyant  flotation.  Other  uses  in  the  developmental  -ta^e 
included  filling  of  aircraft  sections  and  making  sandwich 
•  instruction*. 

I'rea  foams  produced  in  (rennany  were  known  by  tin- 
name  Ifnrka.     The  production  was  large:  about   5<KI  tons 


per  month  of  foamed  material  had  been  produced  for  infla- 
tion in  the  form  of  slabs.  Broadly  the  process  consisted  of 
whipping  air  into  a  special  solution  and  then  hardening  at 
elevated  temperatures.  The  solution  used  was  prepared 
by  condensing  200  parts  of  30%  formaldehyde  with  the  pH 
adjusted  with  60  parts  of  urea,  dry  and  cold,  neutralized 
to  8.0  pH.  Fifty  parts  of  hexanetiol  were  added  and  the 
solution  was  heated  to  95°C  (203°F>  until  one  part  of 
solution  at  20°C  (68°F)  clouded  with  5  parts  of  water.  At 
this  |x>int,  more  urea  was  added  until  the  ratio  of  formaldc 
hyde  to  urea  was  1.7  to  1.  Condensation  was  continued  until 
one  part  of  solution  at  _'o  ( '  clouded  with  1.5  parts  of  water. 
The  pH  was  then  adjusted  to  8.0. 

\    -ecoiid    solution    was    then    prepared    containing 


Thlt   It  th«  fifth   and  concluding   installment   of  tho   toriot   on 
plottict  fabrication   in   Germany.   It  contains   a   ditcuttion   of   od- 


,  in  In. 


ufa 


of  plastics  fo 


crla- 


flnol 


tlon    of   a   f*w    mitcellonoout   fabrication    methods,    and 
summary  and  •valuation. 

Previous  installments  treated  various  other  phases  of  fabrica- 
tion, at  follows  Part  I — injoctlon  and  compression  molding; 
II— ejxrrutlon  and  synthetic  bristles:  III — fllms  and  sheeting  and 

polyvinyl  chloride  pastes    ond  IV synthetic  fibers  an*)  protective 

coatlngi. 


PLASTICS 


AUGUST  194fi 


COWBOY'S 


SaM/e  and  near  *>  All  Western  Plastics  Co.,  Alliance,  Nek 


Working  saddle  and  gear  another 
interesting  application  for  GEON  raw  materials 


THAT  saddle  isn't  a  show  piece — although  it  very 
well  could  be.  It's  a  working  saddle  — and  all  the 
gear  is  working  gear.  All  are  made  from  GEON  poly- 
vinyl  materials  for  the  same  reasons  that  GEON  is  the 
ideal  raw  material  for  such  things  as  shower  curtains 
and  acid  tank  linings,  baby  pants  and  wire  insulation, 
handbags  and  upholstery. 

Products  made  from  GEON  can  be  resistant  to 
water,  chemicals,  foods,  aging,  wear, 
oils,  sunlight,  heat,  cold,  mildew,  and 
most  other  normally  destructive  factors. 
They  may  be  flexible  or  rigid,  clear  or 
opaque,  brilliantly  or  delicately  colored 


Geon 


in  the  entire  color  range.  GEON  can  be  extruded, 
pressure  or  injection  molded,  calendered  or  cast  into 
sheet  or  film.  In  solution  or  latex  forms  GEON  can  be 
used  to  coat  fabrics  and  fibres  of  all  kinds  as  well  as 
paper  and  board. 

Thanks  to  GEON's  versatility  there  are  applications 
in  literally  every  industry.  While  we  make  no  finished 
products  of  GEON  we'll  be  glad  to  work 
with  you  on  any  special  applications. 
Just  write  Department  U-8,  B.  F.  Goodrich 
Chemical   Company,   Rose   Building, 
Cleveland  15,  Ohio. 
•5^"*" 


B.  F.  Goodrich  Chemical  Company 


A  DIVISION  OF 
THE  B   F.  GOODRICH  COMPANY 


- 


IN  PLASTICS 
AND  METALS 


The  range  of  piodncis  and 
p. ills  w here  plastic  and 
metals  call  be  combined 
to  decided  advantage  is 
growing  rapidly  .  .  .  costs 
.111-  iiil  ...  stie.nnlined  design  IIICDMU--  pr.:c- 
lic.d  .  .  .  color  can  be  rcadilv  incorporated. 
KOI  instance,  this  Aulol.ite  distributor  cap 
assies  the  highly  important  precision  po.i 
lioiiing  of  the  metal  contacts,  provides  a 
high  insulation  factor,  gives  low-cost  con- 
struction .  .  .  and  even  this  niilii.u  i.m  item 
shows  ihe  modern  color  eye  appeal  |x>ssiblc 
lliiongli  plastics.  Ihe  nipple's  are  pl.istii. 
IIMI.  in  a  material  which  resists  both  o/onc 
and  oil  in  b:eakdi>wn  lests  far  surpassing 
.111%  ii4Hm.il  In  III  (iindiliuns. 

THE  ELECTRIC  AUTO-LITE  COMPANY 

0oy  Monvfocfurtng   D'vmon 
Detroit    2,    Michigan  ^BflV    City,    Michigaj] 


1m*  to  Ik*   Aufo-liO   «odio  Skew   Starring    Okk  Hoym.i 
fr.r,  Tkunaay  Ni«M.  «KX)  P.M.— t.T.  on  CIS 


Distributor  cap  of  plaiticsand 
metoli,  nipples  of  Elastomer* 
ploitic.  together  with  distribu- 
tor and  spark  plug  wire*;  all 
precision  manufactured  by 
Auto-Lit*. 

• 

$*•  our  catalog  in  Sw**t't 
Fit*  for  Product  Designer*. 


f 


phosphoric  acid,  10%  resorcin,  10%  Nekal  BX  (sodium 
dibutylnapthyl  sulfonate),  and  65%  water.  This  was  the 
foaming  solution. 

In  a  300-gallon  kettle  the  following  mixture  was  whipped 
into  foam  by  stirring  at  200  rpm :  ( 1 )  .3  liters  foam  solu- 
tion in  3.0  liters  water;  (2)  10.0  liters  resin  solution;  and 
(3)  5.0  liters  water. 

The  liquid  foam  was  run  promptly  into  forms  and  set 
in  2  hr.  It  was  then  dried  at  40  to  60°C  ( 104  to  140°F)  for  6 
days,  shrinking  about  20%  during  the  dry.  The  resulting 
slabs  (20"  by  20"  by  .8  to  8")  weighed  15  kg  per  cubic 
meter  (about  1/50  the  weight  of  cork),  and  had  a  com- 
pressive  strength  of  .2  kg  per  square  meter  (2.9  psi).  They 
were  used  mainly  by  the  railroads  for  insulation  and  were 
bonded  into  place  on  cars  by  bitumen  pitch. 

The  second  method  of  foaming  involved  the  addition  of 
special  agents  designed  to  release  gas  under  proper  condi- 
tions and  thus  foam  the  soft  plastics  material.  Experimental 
work  had  been  done  on  polystyrene,  the  phenolics,  and  cellu- 
lose acetate  using  such  foaming  agents  as  ammonium  car- 
bonate. With  this  material,  it  had  been  possible  to  obtain 
some  experimental  moldings  about  4"  thick.  Trials  had 
been  made  on  aircraft  trim  tabs,  but  without  too  satisfactory 
results.  Much  more  successful  work  was  based  on  the  use 
of  the  German  product  known  as  Porophor  N.  Chemically 
this  product  is  azo  isobutyric  dinitrile.  It  has  a  melting 
point  of  103  to  104°C  (218  to  220°F),  and  when  heated 
above  120°C  (248°F)  rapidly  releases  nitrogen.  The  syn- 
thesis of  this  product  is  known  and,  while  not  included  here, 
is  available  if  desired.  Porophor  N  had  been  used  exten- 
sively with  rubber  and  with  polyvinyl  chloride.  Experi- 
mentally it  had  been  used  with  some  success  with  poly- 
styrene. A  typical  formula  for  producing  polyvinyl  chloride 
type  foam  having  a  density  of  .05  (3  Ib  per  cu  ft)  was  as 
follows :  polyvinyl  chloride  type  P — 48  parts ;  tricresylphos- 
phate — 24  parts;  Mesamoll  (mepasin  sulfophenolate) — 8 
parts ;  and  Porophor  N — 20  parts. 

The  general  process  from  either  paste  or  plastics  was  to 
mold  small  pieces  at  160°C  (320°F),  pressure  400  to  600 
kg  per  sq  cm  (5800  to  8700  psi)  for  5  to  7  min.  The  mold 
was  then  cooled  slightly,  and  the  molding  removed  and  al- 
lowed to  stand  at  room  temperature  for  about  an  hour.  Dur- 
ing this  time,  the  volume  increased  6  times.  It  was  then 
immersed  in  hot  water  at  80°C  (176°F)  for  12  to  30  min. 
During  this  time,  the  final  volume  was  reached.  This  flexi- 
ble fine-pored  foam  product  was  used  largely  for  flotation. 
Slabs  about  40"  by  28"  by  8"  were  assembled  to  make  a 
12-man  life  raft.  For  life  boats,  disks  about  15"  in  diameter 
and  3"  high  were  assembled  to  form  its  periphery.  Foamed 
tubes  about  3"  in  diameter  and  5'  long  were  used  to  slip 
over  steel  cables  to  keep  them  afloat.  Production  of  foams 
based  on  Porophor  N  had  passed  the  pilot-plant  stage ;  one 
customer  alone  took  some  12  tons  per  month  of  the  foam- 
ing agent.  This  would  produce  from  60  to  several  hundred 
tons  per  month  of  finished  foam  depending  on  the  percent- 
ages used. 

A  third  method  was  used  to  produce  the  foams  known 
as  Moltopren  which  were  based  on  the  Desmophen-Desmo- 
dur  to  give  a  plastics  which  was  poured  in  place,  foamed 
during  the  cure  to  infusibility,  and  adhered  strongly.  The 
key  material  was  Desmodur.  While  there  were  a  variety  of 
Desmodurs,  they  were  all  characterized  by  the  isocyanate 
end  grouping  (X.N:C:O).  This  end  group  was  very  reac- 
tive and  combined  directly  with  free  hydroxyl  (OH)  groups 
of  alkyds  and  other  materials.  If  the  Desmodur  involved 
included  three  of  these  isocyanate  groupings  per  molecule, 
tlic-n  the  resultant  product  was  cross-linked.  If  the  alkyd 
(Desmophen)  which  is  allowed  to  react  with  the  isocyanate 
(Desmodur)  contained  free  carboxyls  as  well  as  free  hy- 
droxyls,  then  as  the  mass  heated  up,  carbon  dioxide  was 
liberated  to  foam  the  hardening  resin.  In  other  words,  the 


"Porophor"  foamed  polyvinyl  chloride  (above)  has  good 
flexibility.  Below,  foamed  piece  from  mold  is  expanded 
first  by  cooling,  then  by  exposure  to  hot  water  (right) 


A  24-cavity  mold  produced  40,000  tube  caps  in  8  hr 


AUGUST  1946 


PLASTICS 


37 


Hand  colored  medallions,  (old  by  Nazis  to  raise  money, 
show   intricate  die   work   <SPI  Captain   Nolle  collection) 


process  was  one  of  adding  a  trifunctional  isocyanate  to  an 
alkyd  containing  trot-  carboxyls  and  fret-  hydroxyls.  The 
reactants  were  mixed  as  a  dough,  and  the  mass  began  to 
heat  up.  The  reaction  that  took  place  combined  tin-  alkyd 
and  the  isocyanate  into  a  large,  complex  plastics  molecule 
which  liberated  carbon  dioxide  during  the  process.  If  suffi- 
cient foaming  did  not  result,  water  could  be  added  to  the 
resin.  This  reacted  through  estcriiication  of  the  alkyd  to 
give  carbon  dioxide  also.  The  addition  of  aluminum  powder 
was  found  to  greatly  increase  the  compressive  strength 
(25%).  This  may  be  due  to  catalyzing  the  action  of  more 
gas  decomposition  as  well  as  cataly/ing  the  formation  of 
much  smaller  pores  that  tend  toward  greater  strength. 

These  Moltofrcn  foams  were  produced  in  a  wide  range 
of  densities  from  3  Ib  per  cu  ft  to  18  Ib  per  cu  ft.  Com- 
pressivc  strength-,  were  M>  psj  and  860  psi  rcs|>ectively. 
No  external  heat  was  required  in  this  foaming  process  and 
excellent  bonding  was  said  to  reMilt.  thus  making  the  foam 
particularly  desirable  for  aircraft  structures. 

Miscellaneous  Fabrication  Methods 

A  continuous  heat  sealing  Moving  machine  was  developed 
by  I.  G.  Farbeti  and  the  PfafT  Company.  It  was  used  ex- 
••ly  commercially  for  forming  seams  on  soft  calendered 
polyvinyl  chl»rid<-  raincoats,  shipping  bags,  shower  curtains, 
etc.  Its  construction  and  operation  were  relatively  simple. 
The  two  layer*  of  sheeting  to  be  welded  were  passed  be- 
tween two  small  heated  rolls  under  pressure.  These  rolls 
were  built  into  a  modified  sowing  machine  and  were  heated 


electrically  by  conduction.     Sealing  speeds  were  appnfl 
inately  10'  per  minute  on  two  layers  of  .010  to  .015"  thicl 
film.     Bonding  results  were  good  and  the  operating  ted 
nique  was  simple.     The  use  of  high. frequency  continuou 
plastics  welding  had  not  yet  been  developed  in  Germany. 

The  manufacture  of  large  methyl  methacrylate  tubes  b 
a  centrifugal  casting  process  was  found  to  be  practica 
Methyl  methacrylate  monomer  which  had  been  pre-poly 
merized  to  a  viscous  state  was  placed  in  horizontal,  rotat 
ing,  nickel-plated  copper  sealed  tubes  operating  in  an  ova 
The  polymerization  schedules  were  normal.  The  poly  me 
was  annealed  after  polymerization  in  the  tube  and  coole 
vertically.  Normal  sizes  were  8'  long,  and  up  to  10"  in  dian 
eter.  The  largest  ever  made  by  this  process  was  approxi 
inately  28"  in  diameter.  Top  production  was  about  a  to 
per  month. 

A  process  for  making  transmission  belting  from  polyviny 
alcohol  had  developed  to  a  point  where  this  belting  Ml 
largely  making  up  for  the  deficiency  of  top  grain  cowhtd 
belting.     These  driving  belts  (known  as  Drau-erit)   wer 
made    by   casting   many    thin    films    successively,    drying 
stretching,  and  treating  with  phosphoric  acid.     The  casu 
ing  solution  was  30  to  35%  solution  of  polyvinyl  alcoho 
from  U-100,  saponification  No.  15  to  20,  with  20< ;  glycerin 
ther  non-volatile  polyol.    The  belts  were  cast  at  70°( 
(158°F)  in  .1  mm  (.004")  layers  on  a  16  meter  machine 
I'he  belt  made  one  cycle  in  20  min,  passing  through  ho 
air  at  110°C  (230°F),  then  back,  and  resoftened  by  steal) 
just  before  the  next  layer  was  cast.     The  belt  itself  waj 
a  metal  screen  filled  with  polyvinyl  acetate  emulsion  and 
polished  with  a  little  acetone.    A  Ji"  thick  driving  belt  took! 
about  100  layers. 

After  casting  and  drying,  the  belt  was  stretched  fora 
times  its  length  by  passing  10  to  15  times  through  3  pair 
of  pulling  rolls  at  150°C  (302°F).    It  was  then  immerse* 
in  60%  phosphoric  acid  at  25  to  30°C  (77  to  86°F)  fa 
15  to  20  minutes  immersion  per  millimeter  of  belt  thick 
ness  (2  hr  for  a  3/16"  belt),  then  removed  and  dried 
room  temperature  for  about  two  weeks.     Approximati 
J-",  of  phosphoric  acid  had  been  absorbed,  and  the  ilcxin 
of  the  product  was  greatly  improved.    For  flexing,  the 
stood  four  times  as  much  as  leather  and  40  times  as  time 
as  when  untreated  with  phosphoric  acid.    It  swelled  in  col< 
water  and  ultimately  dissolved  in  hot.    The  elongation  waj 
somewhat  higher  than  for  leather,  but  the  strengths  and  life 
were  very  good.    The  belts  were  joined  by  scarfing  the  ends 
and  cementing  with  polyvinyl  alcohol  solution.   Because  oi 
their  moisture  susceptibility  they  were  found  very  desirable 
where  antistatic  transmission  lielting  is  necessary. 

Conclusion 

German  plastics  and  the  plastics  fabrication  industry  in 
Germany  was  large  when  the  size  of  the  country  and  its 
population  were  considered.  Many  of  the  developments  m 
basic  plastics  resins  and  in  fabrication  went  along  other 
directions  than  in  the  U.  S.  This  was  due  both  to  their 
supply  of  available  raw  materials  and  the  manner  in  which 
that  supply  differed  from  ours,  and  to  their  industrial  and 
domestic  demands,  which  were  not  always  along  the  same 
lines  as  those  in  the  United  States. 

Their  fabrication  developments  were  somewhat  spotn 
Their  advances  in  injection  molding  were  not  nearly  as 
great  as  in  the  United  States.  In  compression  molding  they 
had  mined  toward  the  production  of  larger-sized  moldings 
and  in  some  rcs|xvts  were  outstanding  in  that  field.  'I  hey 
had  develo|K-il  several  mui|iie  methods  of  extrusion,  and  the 
products  of  this  industry  were  generally  of  good  quality. 
Some  of  their  films  held  considerable  interest,  while  others 
appeared  to  be  somewhat  mediocre.  With  coatings  they  had 
done  well,  considering  their  veiy  limited  supply  of  imp 
(Continued  on  page  93) 


Pl.tMTff'M 


AtlGl'ST  194« 


TO  ATTAIN  excellence  in 
plastic  molding,  many  steps- 
each  an  essential  part  of  the 
whole  process  — must  be  fol- 
lowed through  accurately  and 
thoroughly. 

Every  step  of  the  way-design- 
ing,   mold    making,    molding, 
and  finishing-calls  for  the  high- 
est skill   and   experience,  plus 
the  proper  plant  facilities  for 
efficient  production.  Combined 
these  operations  can  result  i_ 
quality  molding... plastics  that 
"measure  up"  in  performano 
appearance  and  cost. 

MACK  experience  and  proven 
methods,  plus  three  completely 
equipped  plants,  offer  plastic 
molding  that  qualifies.  Your  in- 
quiries are  solicited;  address 
Mack  Molding  Company,  Inc., 
100  Main  Street,  Wayne,  N.  J. 


MOLDED 
EXCELLENCE 


MACK  PLANT  AT 
ARLINGTON,  VERMONT 


MACK  PLANT  AT 
WATERLOO,  P  Q.,  CANADA 


SALES 


MACK  PLANT  AT 
WAYNE,  NEW  JERSEY 


IN       PRINCIPAL      CITIES 


AUGUST  1946 


PLASTtCS 


39 


Textiles  on  the  Wall 


-i* .»  ••    %^ 
+  \.  *\  V  » *i 

*.    .  '  >»•*  V*,^  ^. 

x    ••-•  v^  **  *i 
.  .••  ^^»  *'  ••» 

•    *  *.   *  >     •»      •; 

\*'".-'-rv  ••-*:. i 

-..'-:^;*/-A**;,v 

Typical  patterns  oi  the  new  resin-impregnated 
fabric  wall  covering,  in  which  color  and  beauty  of 
design  are  intensified  and  protected  by  plastics 


Increased  Interior  beauty,  and  saving  In  labor, 
is  accomplished  by  using  silk  taffeta  plaid  "Wall- 
fab"  on  walls  over  kitchen  utility  installations 


A  novel  type  of  colorful  and 
durable  covering  for  interior 
walls,  created  by  impregnation 
of  fabric  with  synthetic  resins 


J  JC.   & 


can 


FABRICS  of  the  loom,  like  tapestries  of  olden  days,  ar< 
finding  utilization  as  wall  covering  in  modern  homes 
in   a   product  called   Walliab,   manufactured  by   Peerlesi 
Plastic  Products  Montebello,  Calif. 

Resins  encase  every  strand  and  brighten  each  pinpoint  of 
color  of  the  textiles  in  this  new  product.  Yet  the  signif 
icance  of  the  process  employed  in  its  making  is  in  the  dis 
covery  of  a  method  of  treating  dye-decorated  fabrics  \\itl 
synthetic  resin  without  causing  the  design  dye  to  run  am 
streak,  according  to  Merwyn  C.  Gill,  chemical  engineer  am 
developer  of  Wallfab. 

The  product  is  described  as  a  "two-ply  laminate  of  j>a|H.-i 
and  fabric  impregnated  with  a  polyester  thermosettmj 
resin."  Its  preparation  is,  to  date,  done  by  hand,  but  it 
manufacturer  expects  that  it  will  eventually  be  produced  b 
social  machine.  Although  some  impregnated  laminates  ar 
machine-processed,  a  device  that  will  handle  bolts  of  clot 
without  permitting  sag,  or  stretching  the  weave,  is  no 
simple  to  design  or  build,  according  to  Mr.  Gill.  The  clot 
must  be  absolutely  straight  when  laid-up,  hi-  advises. 

Under  the  present  process,  the  work  of  turning  out 
standard  8'  by  3'  strip  of  Wallfab  is  handled  as  follows : 

A  sturdy,  rigid  sheet  of  plate  glass  or  Masonile  is  lai 
mi  the  workbench  and  covered  with  a  sheet  of  cellophane. 

The  paper  which  serves  as  a  backing  for  the  cloth  am 
provides  support  for  the  fabric,  as  well  as  extra  strengt 
in  the  wall-covering  strip,  is  placed  on  the  cellophanc-cov 
ered  glass  or  Masonite  and  is  bathed  in  synthetic 
This  resin  is  worked  into  the  paper  and  spread  evenly  nm 
completely  with  hand  squeegees.  The  paper  is  then  re 
versed,  and  Imtli  sides  are  thoroughly  impregnated. 

The  desired  cloth,  which  may  be  a  plain  color,  a  con 
inercially-produced  fabric  of  varied  pattern  or  a  silk 
•created  custom-designed  textile,  is  placed  over  the  in 
pregiiated  paper,  carefully  "squared  up"  and  given  th< 
snaking.  Again,  squeegees  are  used  to  work  the  resin  int 
and  through  the  textile. 

Another  sheet  of  cellophane  is  placed  over  the  fabric 
followed  by  a  top  layer  of  rigid  glass  or  Masonite;  or,  by  a 
alternate  method,  the  top  covering  may  be  eliminated  if  meta 
Iwrs  arc  placed  along  the  edges  to  hold  down  the  cellophan 
in  preparation  for  the  next  step. 

40 


Close-textured  materials,  such  as  this  floral 
patterned  cotton,  lend  themselves  most  satis- 
factorily to  the  resin-treating  process  used 


Hand-operated  "squeegees"  are  used  to  work  the 
liquid  resin  into  fabric  aiter  it  has  been  placed 
over  backing  which  is  completely  resin-saturated 


Clamps  are  then  affixed  tightly  to  the  four  sides  of  the 
pressed-down  "lay-up,"  making  it  ready  for  the  oven.  It 
is  placed  with  others  on  a  rolling,  multi-trayed  cart  and 
wheeled  inside  a  large  oven  to  be  "cooked"  at  a  tempera- 
ture of  approximately  250°  F  for  about  two  hours.  The 
heat  transforms  the  resin  from  a  sticky  gum  into  a  solid 
substance,  welding  the  paper  and  cloth  into  an  inseparable 
laminate. 

Various  kinds  of  fabric  are  used  in  making  Wallfab, 
among  them  being  muslin,  denim,  cotton  herringbone, 
Osnaburg,  and  silk  taffeta.  Such  diversity  provides  home 
decorators  with  a  much  wider  selection  of  patterns,  colors 
and  designs  than  is  customarily  available  in  wall  paper  or 
other  types  of  wall  covering.  If  none  of  the  company's 
inventory  of  patterns  should  appeal  to  a  particular  designer, 
it  is  possible  to  select  nearly  any  fabric  to  be  found  on  the 
cloth  merchant's  shelf  and  have  it  impregnated.  Occa- 
sionally a  cloth  so  dyed  that  it  resists  the  Wallfab  method 
is  encountered,  but  such  instances  are  said  to  be  confined 
to  cheaper  materials,  high-quality  fabrics — especially  vat- 
dyed  products — being  mentioned  as  virtually  certain  to 
"hold  up"  under  impregnation. 

The  chief  benefit  of  impregnated  fabrics  for  covering 
walls  is  in  its  durability,  with  added  beauty  constituting  a 
close  second.  The  resin's  tough  composition  permits  scour- 
ing of  the  product,  if  necessary,  to  remove  dirt  and  stains. 
It  is  not  harmed  by  soap  and  water,  although  unduly  inten- 
sive and  prolonged  scrubbing  could  effect  minor  damage.  It 
is  conceivable  that  a  deep  scratch  which  would  irreparably 
mar  a  paper  covering  could  scar  the  resin  "hide"  of  Wall- 
jab,  but  it  would  be  difficult  for  it  to  penetrate  deeply 
enough  to  rip  the  locked-together  textile  threads  which,  en- 
cased in  plastics,  are  afforded  protection  from  exterior 
damage. 

The  resin's  high  index  of  refraction  heightens  the  appeal 
of  colors  in  the  product.  For  example,  in  a  taffeta  plaid, 
the  crossing  of  blue  and  red  threads  does  not,  in  the  original 
fabric,  produce  a  purple  shade,  but  under  impregnation  this 
blend  is  achieved.  Colors  seem  sharper  and  richer,  impart- 
ing more  of  a  sheen.  The  resin  also  blocks  off  much  of  the 
color-fading  ultraviolet  rays  of  sunlight. 
(Continued  on  page  74) 


Metal  strips  hold  cellophane  covering  firm  and 
taut  in  position  over  fabric  and  backing,  as  lay- 
up  is  put  in  oven  for  2  hours  at  about  250°  F 


Removal  of  cellophane  protective  sheet  from  lay- 
up  after  baking  reveals  the  completed  "Wallfab," 
with  its  color  and  design  preserved  in  plastics 


AUGUST  1946 


41 


DECORATIONS 


CHANNELS 


OVERNIGHT  BAGS 


POCKETBOOKS 


YOUR  FINISHED  PRODUCT 

IS  ONLY  AS  GOOD  AS 

THE  SKILL  AND  INTEGRITY  OF 

YOUR  SUPPLIER 

Here,  with  excellent  manufacturing  facili- 
ties, with  volume  capacity,  we  are  ideally 
equipped  to  produce  Extrusion  Molded 
Thermoplastics  under  skilled  supervision. 
Your  specifications — your  tolerances  are 
rigidly  observed  to  insure  Quality  in  your 
product. 

WithC 


BELTING 


TUBING 


SHEETINGS  for  handbags,   overnight  cases,    beach 
bags,  etc. 

STRIPS  for  woven  upholstery,  belts,  straps,  trimming, 
footwear. 

TUBING  for  wiring,  conduits,  flexible  shafts,  piping, 
etc. 

RODS  for  handles,  plungers,  furniture,  rails,  industrial 
uses. 

CHANNELS  for  weather-stripping,  cushioning,  etc. 

SPECIAL  SHAPES  for  ornaments,  trim,  parts,  acces- 
sories, etc. 

COLORFUL,  TRANSPARENT  or  OPAQUE 
FLEXIBLE  or  RIGID 


UPHOLSTERY 


/ 


FOOTWEAR 


Afasutjacfoie'id,   oj  9*fj,ectijo.*t   Molded 

Complete  Technical  Service  —  Design,  Engineering  and  Production 


CELLIIPLASTIC  CORPORATION 


OP  P. 


NIW     rot*     OfftCI-HO     ""*    AVfNVf 


PLASTIC     CONTAINERS 

AND 

PLASTIC    PRODUCTS 

46     AVENUE    I  NEWARK    5.   N.   J. 

vf  wisr  cOAir.   CONIAINI*    titvict   COMPANY,  tos   AWOIUS   3f.  CAI 


42 


AIMJIST   !«». 


Glamorizing  the  Guitar 


Use  of  plastics  adds  graceful 
lines  and  harmonious  coloring 
to  popular  musical  instrument 


Four  steps  in  the  "Ultratone's"  evolution  show  (1)  the 
rough  piece  of  maple  used.  (2)  the  maple  alter  it  has 
undergone  several  operations,  (3)  finished  instrument, 
and  (4)  the  guitar  complete  with  all  parts  assembled. 
Above,  various  stages  in  the  manufacture  of  the  beau- 
tifully designed  and  colorful  acrylic  peghead  cover 


THE  tone  quality  of  a  musical  instrument  has  been  and 
is  considered  its  most  important  attribute,  whereas  its 
appearance  has  been  a  lesser  consideration,  with  the  aspect 
of  color  being  practically  negligible.  Lately,  however,  the 
IMissihilities  of  "dressing  up"  musical  instruments,  particu- 
larly for  dance  orchestra  use.  have  become  apparent.  And 
plastics,  with  their  lightness  of  weight,  color  and  versatility, 
present  outstanding  potentialities  for  such  application. 

An  electric  guitar,  called  the  L'llratonc.  which  possesses 
both  tone  appeal  and  eye  appeal,  owes  much  of  its  attrac- 
tiveness to  plastics.  Designed  by  Barnes  &  Reinecke,  Chi- 
cago, for  Gibson  Inc.,  of  Kalamazoo,  Mich.,  the  graceful 
lines  and  harmonious  coloring  of  this  instrument  make  it 
•  iitt standing  in  appearance.  Its  tonal  quality  is  said  to  be 
"equal  if  not  superior"  to  that  of  the  conventional  steel 
guitar,  and  a  wide  tonal  range  is  made  possible  through 
three  controls — two  operated  by  hand,  one  by  foot. 

The  body  of  the  instrument  is  formed  of  maple  finished 
in  gleaming  white  enamel,  while  the  access  plate  on  the 
base  is  of  a  black  paper-based  laminate,  as  is  the  small 
cover  plate  on  the  pick-up  unit  at  the  lower  end.  A  flock- 
ing material,  not  used  for  the  present  instrument,  is  to  In- 
applied  to  the  hack  surface  of  future  models  to  prexen' 
sliding. 

The  fingerboard,  of  transparent  acrylic,  with  machined  m 
position  markers,  pitch  markers  and  frets  lacquered  in  U"M 
and  coral  from  the  underneath  side,  constitutes  a  dccoratix  • 
touch  as  well  as  tuliillmt;  its  musical  purjiosp.  It  is  fabri- 
cated in  the  (iil»on  plant. 

hecorative,  also,  are  the  peghead  cover  at  the  top  and 
the  unit  cover  at  the  lower  end  of  the  instrument — the  top 
cover  in  white,  silver  and  gold  and  the  lower  cover  adding 
a  gmy  note  in  soft  coral  color,  i-'or  the  model  shown  as  the 
cover  illustration,  the  peghead  cover  wa«  made  from  a  Mat 


44 


acrylic  sheet  3ie"  thick  heated  to  a  softening  temperat 
in  the  lower  half  of  a  stretch-forming  die.    The  upper 
of  the  die  was  then  placed  in  position,  and  the  material 
formed  and  allowed  to  cool  under  pressure.  The  coral 
cover,  also  of  acrylic,  goes  through  the  same  process 
the  preliminary  stages  of  manufacture.    Both  covers  on 
instrument  pictured  were  formed  from  transparent  acryli 
sheet  ami  were  then  decorated  by  lacquering  on  the  mule 

tide, 

The  company  name  and  trade  name,  which  appear  re 
s|K-ctively  on  the  top  and  bottom  covers,  are  machined  in 
on  the  under  side  and  the  depressions  lacquered  in.  Th( 
former  appears  in  gold  on  a  white  background  and  the  latter 
in  white  against  coral. 

Latest  specifications  call  for  both  protective  covers  to  bt 

the  top  from  transparent  Catalin.  which  will  then  he 

lacquered  in  the  same  manner  as  the  present  formed  acrylic 

cover,  and  the  bottom  from  coral  Catalin.    Thus  for  this 

lower  cover  the  lacquering  process  will  be  eliminated. 

The  peg  buttons  on  the  tuning  keys  are  produced  in 
matching  coral  shade;  of  cellulose  acetate,  they  are  inje 
tion  molded  by  the  Kluson  Co.,  Chicago.    One  volume 
two  tone  control  knobs,  of  clear  acrylic  touched  with  gil 
are  cut  and  formed  from  rod  stock  extruded  by  Coloni 
Kolonite  Co.,  Chicago. 

Colorful  and  unusual,  this  guitar,  spotlighted  in  a  dance 
orchestra,  becomes  a  focal  point  of  visual  interest. 

Plastics  has  its  place  in  the  case  for  this  instrument  M 
well  (see  cover  illustration):  the  outer  covering  is 
Pout   l-'ahrii;>id  in  luggage-tan  color,  contrasting  smartly 
with  the  inner  lining  of  crimson  plush. 

This  is  a  de  luxe  model,  priced  at  $316.55  for  instrumefll 
amplifier,  and  rase,  while  the  instrument  alone  sell-  for 

INC 


AUGUST    I'M* 


:  What  kind 
of  high  frequency 
heating  equipment 
is  best  for  plastics 


:  The  kind  that  has  been  developed 
specifically  for  the  plastics  industry! 


GOING  to  convert  to  the  high  fre- 
quency or  electronic  preheating 
of  plastic  materials?  Find  out  about 
THERMEX  Red  Heads.  They  constitute 
the  most  complete  line  of  electronic 
generators  developed  specifically  for 
this  purpose. 

There  is  a  THERMEX  Red  Head  to 
fit  your  needs.  Completely  self-con- 
tained, with  the  automatically  timed 
sliding  drawer  heating  compartment, 


every  THERMEX  Red  Head  is  simple 
to  operate,  simple  to  maintain,  depend- 
able. And,  portable,  slim  in  relation  to 
capacity,  every  THERMEX  Red  Head 
fits  readily  into  your  present  press 
layout. 

Write  to  The  Girdler  Corporation, 
Thermex  Division,  Louisville  1,  Ky. 
District  offices:  1 50  Broadway,  New 
York  7;  228  N.  La  Salle  St.,  Chicago  1; 
1836  Euclid  Ave.,  Cleveland  15. 


The  First  Industrial  High  Frequency  Dielectric  Heating  Equipment 


THERMEX  and  REDHEAD—  Trade  Marks  Reo.  V.  S,  Pat.  Off 


FIRST 
WITH  THE   MOST 
ADVANTAGE  S: 


The  Fimous  Thermex  Drawer 
Dual  Timer  Control 
Portability 
Dependability 


Automatic  Signal  Light 
Automatic  Resetting  Timer 
Convenient  Working  Height 
Accessible  Control  Panels 
Large  Load  Area 
Warp- proof  Load  Tray 
Adequate  Metering 


Overload- Underload  Protection 
Automatic  Safety  Switches 
Air  Gap  with  All  Loads 
Rugged  Construction 
Compact  Design 
Heavy  Duty  Cabinet 
Economical  Use  of  Powtf 


IUGUST  1946 


PLASTICS 


45 


Cardboard  or  (heeling  will  make  a  good  bottom  for  t  hi*  "Ethocel"  longitudinally-seamed  cylindrical  container 

Part  III.  Drawn   containers  are  attractive  and  simple 
to  make,  but  are  limited  by  depth  of  draw  and  diameter 


y    WIJ  W,j,,» 


BECAUSE  the  drawn  container  i-  Dimple  to  make  and  has 
no  seam  like  other  types  of  plastics  containers,  it  is 
theoretically  the  ideal  type  regardless  of  size  or  shape.  Nut 
having  a  seam,  it  is  superior  in  attractiveness  and,  there- 
fore, in  sales  ap|n-al ;  and,  from  the  fabrication  standpoint, 
it  can  ultimately  become  more  economical  because,  since 
the  operational  sequence  is  simpler,  the  machinery  required 
will,  when  refined,  he  simpler  in  construction.  It  would 
appear,  therefore,  that  the  development  of  continuously 
automatic  means  for  the  making  of  containers  of  rigid 
sheeting  might  to  move  in  the  direction  of  the  drawing  or 
forming  proo---.  \  number  of  factors,  however,  limit 
the  field  ni  actiini  tit  forming  machines.  One  is  the  ratio 
of  the  ili-pth  of  draw  to  the  diameter  of  the  container.  Tin- 
best  ratio  obtained  so  far  is  a  1  :1  draw.  In  time,  this  ratio 
will  undoubtedly  be  widened,  but  there  will  still  remain  a 
large  field  of  container  t\|»--  whose  depth  of  draw  will  be 
beyond  the  capabilities  of  the  forming  machine.  Long  tubu- 
lar containers  are  just  one  example. 

Another   limiting  fact-n    i-  the  diameter  or,   in  square 


container--,  the  side  dimensions.  In  hand-  or  foot-operated 
presses,  containers  of  a  diameter  as  wide  as  10"  have  Ix-en 
drawn,  but  in  automatic  and  semi-automatic  machines  no 
diameter  of  this  size  has  yet  become  feasible  in  actual  pro- 
duction. The  problem  of  range  of  diameter  will  be  easier 
to  solve  than  that  of  draw  ratio.  In  fact,  the  greater  the 
diameter,  the  more  difficult  it  is  to  achieve  a  draw  ratio 
even  approaching  the  present  maximum  of  1  :  1.  The  bead- 
ing of  rectangular  drawn  containers,  already  referred  to,  is 
another  limitation  on  the  progress  of  the  drawn  product. 

Continuously  automatic  drawing  or  forming  of  rigid 
sheeting  from  feed  to  finish  is  a  reality.  Designed  and  de- 
veloped by  the  Celanese  Corporation  of  America,  the  new 
machine  was  operated  continuously  on  government  ordei- 
from  1941  until  war's  end.  Since  Celanese  does  not  fabricate 
its  materials  for  end  UM--,  it  h.i-  licensed  the  manufacture 
of  the  machine  to  the  F.  I..  Smitlie  I'o.,  New  York,  who 
will  produce  it  and  who  arc  now  redesigning  it  to  effect 
a  number  of  improvements  lief  ore  putting  it  into  produc- 
tion. These  include  increasing  the  size  range,  increasing 


PLASTICS 


U<;iST    1!M6 


the  depth  of  draw,  speeding  up  die-changing  procedure  and 
facilitating  handling.  The  company  expects  the  first  of 
the  machines  to  be  on  the  market  at  the  end  of  summer. 

The  automatic  forming  machine  ties  together  in  automatic 
continuity  three  major  units  of  operation  hitherto  indi- 
vidually and  manually  executed.  These  are  automatic  feed- 
ing, automatic  drawing,  and  ejection.  There  is  nothing 
especially  new  about  automatic  drawing  in  itself.  What 
is  novel  about  it  is  its  tie-in  and  synchronization  with  the 
drawing  cycle.  Automatic  drawing,  with  cut-off  and  strip- 
ping, is,  however,  entirely  new.  Ejection  is  synchronized 
with  the  cut-off  operation.  This  replaces  previous  hand 
removal. 

What  has  been  accomplished  by  the  design  of  this  machine 
and  how  it  developed  from  the  piece-meal  manual  operations 
can  best  be  understood  from  an  analysis  of  the  drawing 
processes  now  generally  prevailing.  The  drawing  die  is 
the  heart  of  all  drawing  processes.  In  order  to  maintain 
uniformity  of  clearances  under  changing  heating  and  cooling 
conditions  in  the  course  of  operations,  it  is  well  to  make 
all  parts  of  the  same  metal,  preferably  high-carbon  steel, 
with  the  die  and  cut-off  of  tool  steel.  The  die  element  is  an 
open  metal  plate,  mounted  on  a  cooling  box,  with  a  hold- 
down  plate  on  the  male  half.  Their  opposing  surfaces  are 
perfectly  parallel  and  smooth.  The  blank  is  fed  between 
them.  The  forming  head  is  usually  cored  for  either  cooling 
or  heating.  The  dimensions  of  the  forming  head  are  the 
same  as  the  inside  dimensions  of  the  piece  to  be  drawn. 
The  forming  head  has  a  side  taper  of  about  .003"  per  in. 
of  depth  to  facilitate  stripping  off  the  drawn  piece.  The 
clearance  between  the  side  of  the  forming  head  and  the 
perimeter  of  the  die  plate  opening,  at  their  operating  tem- 
perature, is  equal  to  the  thickness  of  the  material  plus  .002" 
to  .005",  depending  on  the  gauge  of  the  sheeting.  The  open- 
ing in  the  hold-down  plate  is  from  1/32"  to  1/16"  wider 
than  the  opening  in  the  die  plate.  A  slight  radius  in  the 
upper  rim  of  the  die  plate  opening  facilitates  sliding  of 
the  stock. 

The  drawing  die,  maintained  at  a  temperature  of  from 
220°  to  290°  F  for  cellulose  acetate  and  from  240°  to  260°  F 
for  ethyl  cellulose,  depending  on  thickness  of  stock,  is 
mounted  in  a  manual  press  or  in  a  foot-operated  press.  Feed- 
ing is  by  hand.  The  blank  is  positioned  on  top  of  the  die  plate 
against  guide  pins.  The  hold-down  plate  is  brought  down 
on  the  blank  and  tension-pressed  on  it  during  the  drawing 
process.  The  hold-down  may  be  separately  operated  by 
foot-pedal  or,  as  is  more  often  the  case,  may  be  spring- 


Two  stages  in  the  evolution  oi  the  automatic  drawing  ma- 
chine are  the  wholly  hand  operated  press  (above)  and  the 
semi-automatic  press,  in  which  the  automatic  feed  has 
replaced  hand  feed,  the  other  operations  remaining  manual 


Viewing  terminal  end  of  automatic  machine,  which  dupli- 
cates action  of  manual  machine  by  a  cam-actuated  device 


AUGUST    1946 


I'LASTMCS 


47 


DRAWN  PIECE 


-HOIO-DOWN  PLATE 
~FOtMlN6  Mf»D 


Forming  die  ol  the  continuously  automatic  machine 

engaged  with  the  plunger  so  as  to  act  on  the  blank  imme- 
diately in  advance  of  the  forming  head.  Since  the  material, 
in  the  act  of  drawing,  is  pulled  down  from  under  the 
hold-down  plate,  the  pressure  of  this  plate  must  be  light 
enough  to  permit  the  blank  to  slip  away.  On  the  other 
hand,  the  pressure  must  be  great  enough  to  prevent  wrin- 
kling of  the  material.  As  soon  as  the  hold-down  plate  is 
properly  seated,  the  forming  head  makes  contact  with  the 
blank  and  pushes  it  into  the  die  opening,  drawing  the  ma- 
terial tightly  to  itself.  The  stroke  halts  for  a  short  dwell 
to  permit  the  material  to  cool  and  to  set  against  the  forming 
head. 

In  some  cases,  retraction  of  the  forming  head  and  hold- 
down  plate  and  stripping  of  the  drawn  piece  completes  the 
operation  on  this  press.  The  excess  flange  on  the  piece  is 
then  removed  either  by  blanking  it  off  or  by  sawing  (usually 
band-sawing)  it  off  against  a  guide.  These  and  other  meth- 
ods of  removing  flanges  in  a  separate  operation  are  rapidly 
losing  ground  in  favor  of  a  chop-out  operation  performed 
in  the  press  itself  immediately  after  the  drawing. 

The  total  cycle  of  operation  in  the  press  is  as  follows: 
feed,  downstroke  (to  contact  of  forming  head  with  blank), 
dwell,  downstroke  (drawing),  dwell  (setting),  downstroke 
(chop-out),  upstroke  (retraction),  stripping  and  ejection 
of  finished  piece  and  chopped-out  flange.  Every  movement 
is  manual  or  pedal.  It  is  well  to  keep  this  cycle  in  mind 
for  the  later  discussion  of  the  automatic  forming  machine. 

There  are  a  number  of  precautions  to  be  observed  in 
drawing  rigid  sheeting.  Rate  of  production  is  a  compro- 
mise between  a  speed  that  is  so  great  as  to  tear  or  distort 
the  material  and  one  that  is  so  slow  as  to  permit  cooling  to 
advance  before  the  drawn  piece  is  set.  To  prevent  destruc- 
tion of  the  material,  clearances  between  the  forming  head 
and  the  die  opening  are  made  small,  which,  in  turn,  means 
that  alignment  Ix-twc.  n  the-e  two  members  should  be  quite 
exact.  It  might  also  IK-  (minted  out  that  draw  ratio  limits 
should  be  kept  in  mind.  While  a  1 :  1  ratio  of  depth  of  draw 
tn  'liameter  is  a  possibility  in  pieces  of  W  and  less,  it 
becomes  smaller  as  diameter  increases. 

4ufomof/c  Forming  Machine 

The  design  of  the  Celanese  automatic  funning  machine 
started  with  the  conception  of  the  manually  operated  press 
as  a  base.  By  means  of  a  simple  nvnrding  nu-eliam-tn 
attached  to  the  press,  a  motion  -tmly  analysis  showed  the 


following  motion  cycle  by  the  operator:  rapid  downstroke 
until  the  forming  head  touched  the  material;  dwell;  accel- 
eration of  motion ;  uniform  motion ;  de-acceleration ;  dwell : 
sharp  short  motion  for  cut-off ;  return  to  zero  by  an  accel- 
eration; uniform  motion;  de-acceleration. 

The  designers  decided  that  the  simplest  method  of  dupli- 
cating the  variability  of  motion  involved  in  this  cycle  was 
by  means  of  cams.  Quick  interchangeability  of  cams  was 
provided  for  in  the  camshaft.  Also  the  increasing  spring 
pressure  of  the  hold-down  plate  on  the  material  as  the 
forming  head  advanced  was  undesirable.  In  fact,  in  some 
types  of  operation,  it  is  necessary  to  decrease  the  hold- 
down  pressure  as  the  piece  is  being  drawn,  while  in  other- 
constant  pressure  is  required.  Cams  were  designed  for 
the  solution  of  this  problem  also.  And  cams  were  again 
used  in  the  design  of  the  knock-out  mechanism,  replacing 
the  delicate  and  easily  disturbed  stripper  fingers. 

The  manual  operations  (feed,  drawing,  cut-off,  stripping, 
ejection)  were  made  automatic  and  tied  together.  The 
problem  of  feeding  to  the  drawing  unit  was  solved  by  elim- 
inating the  die-cutting  of  blanks  to  size  and  substituting 
roll  feed,  in  which  the  material,  in  a  continuous  strip,  was 
paid  out  from  a  shaft-mounted  roll  and  hitch-fed  to  the  , 
drawing  unit  in  synchronization  with  the  action  of  the 
drawing  die.  Where  preheating  was  necessary,  the  strip 
was  passed  over  a  hot-plate  on  its  way  to  the  press.  At  the 
terminal  of  the  operation,  automatic  ejection  was  effected 
by  installation  of  air  jet  ports  in  the  forming  head.  One 
blast  kicked  the  finished  piece  off,  and  a  second  blast  blew 
the  piece  and  the  knocked-out  flange  into  the  collecting  bin. 
Heat  control  was  made  accurate  at  all  heating  points,  in- 
cluding the  temperatures  of  dies  and  hold-down  plate. 

An  accompanying  set  of  photographs  shows  three  steps 
in  the  evolution  of  the  automatic  forming  machine.  The  first 
shows  a  manually  operated  press.  The  die-cut  blanks,  pre- 
heated on  the  hot-plate  at  the  operator's  left,  are  left-hand- 
fed  to  the  drawing  die,  which  is  brought  down  by  the  right 
hand  for  the  drawing  and  chop-out  operations.  It  might 
be  pointed  out  that  a  considerable  degree  of  manual  pressure 
control  is  required  at  this  point,  as  well  as  double-dwell 
timing,  to  permit  gradual  draw.  The  drawn  piece,  knocked 
off  the  die  by  stripper  fingers,  is  removed,  together  with 
the  flange,  by  hand. 

A  long  step  toward  continuity  of  operations  has  been 
taken  in  the  set-up  of  the  second  photograph.  Hand  feed 
has  been  replaced  by  roll  feed,  the  strip  of  sheeting  being 
fed  in  at  the  right  and  issuing,  after  drawing,  on  the  left, 
where  it  is  rerolled  on  another  reel.  The  waste  strip,  which 
can  be  seen  to  the  left  of  the  operator's  knee,  looks  much 
like  a  strip  out  of  which  a  blank  has  been  cut  Hand  and 
foot  operation  has  not  yet  been  eliminated  in  this  model 
of  the  machine.  They  are  both  used. 

In  the  third  photograph  is  the  continuously  automatic 
forming  machine,  the  view  l>eing  taken  at  the  terminal  end. 
The  only  operating  attention  the  machine  requires  is  the 
mounting  of  new  rolls  of  sheeting  as  the  old  ones  give  out, 
which  means  that  one  operator  can  attend  several  machines. 
At  the  moment  that  this  view  was  taken,  the  container  had 
just  been  drawn  and  chopped-out  and,  on  the  completion 
of  the  upstroke,  was  to  be  air-ejected  from  the  press,  while 
the  remaining  strip  from  several  previous  drawing  cycles 
is  being  rereeled  for  later  reuse  for  other  purposes.  Tin- 
machine  contains  what  is  perhaps  the  heart  of  the  mechan- 
ization of  the  drawing  operation  itself,  a  cam-actuated  dou- 
ble-hesitation movement  that  duplicates  the  manually  con- 
trollei!  dwells  of  the  two  older-type  machin 

During  the  last  year  of  the  war,  the  Celanese  company 
at  its  Newark,  N.  J.,  plant,  operated  a  battery  of  ten  of 
these  automatics  for  the  government  for  the  production  of 
ammunition  components.  In  its  last  improved  form,  the 
machine  was  producing  small  container-  with  a  draw  ratio 
'  tinurd  on  page  73) 


48 


I'LASTiCS 


AUGUST  1946 


is  the  7th  Nile  Club  we've  taken 
this  Michigan  Molded  Engineer  to,  and 
he  still  won't  take  an  order!" 


ICHIGAN 

OLDED    PLASTICS,  INC. 


AUGUST  1946 


PLASTICS 


49 


Presenting  a  sampling  of  the  drawing  instrument  types 
which  during  the  war  served  thousands  of  service  men 
in  anti-aircraft  training,  reconnaissance  work,  target  lo- 
cation, map  reading,  etc.,  and  which  are  proving 
their  worth  again  in  numerous  civilian  applications 


(/enn*e  *^- 


C-fhru    Ruler  Company 


TIIKKK  have  been  many  revolutionary  developments  in 
plastics  drawing  instruments  during  the  last  decade, 
not  the  least  being  the  transition  from  stubborn  resistance 
against  them  to  ready  acceptance.  Thus,  today,  plastics 
instruments  are  often  preferred  to  the  non-plastics  kind, 
and  while  there  arc  many  good  reasons  for  this  preference, 
they  revolve  mainly  around  the  fact  that  the  plastics  now 
available  have  made  it  possible  to  design  and  produce  in- 
struments which  incorporate  time-saving  features  and  com- 
puting advantages  hitherto  unobtainable.  'I  lie  speedy  con- 
sumer conversion  to  plastics  products,  within  a  compara- 
tively short  span  of  time,  can  perhaps  be  best  illustrated  by 
the  following  cxpcri' 

About  fourteen  years  ago,  while  on  a  nation-wide  promo- 
tion trip,  the  author  visited  an  office  supply  dealer  in  a 
to  try  to  interest  him  in  a  time- 

s.ivmj,'  pl.i-tics  ruler.  He  showed  a  conspicuous  lack  of  in- 
terest and  remarked  that  he  had  never  had  calls  for  such 
an  item.  He  said  he  was  satisfied  to  handle  a  12"  wooden 
ruler  at  a  price  of  5*  rather  than  the  6"  plastics  ruler  at 


35< ;  furthermore,  he  was  not  interested  in  diverting  busi- 
ness from  a  long-established  supply  of  wooden  measuring 
devices — an  admirable  display  of  loyalty.  Persistence 
finally  broke  through  the  almost  impregnable  resistance  of 
the  dealer,  and  he  finally  condescended  to  take  time  to  ob- 
serve the  plastics  ruler  and  read  the  descriptive  literature. 
Since  he  was  not  pressed  for  an  immediate  order,  he  mel- 
lowed considerably.  He  even  acknowledged  a  recent  re- 
quest for  some  special  "all-clear"  rulers. 

Such  resistance  was  not  an  isolated  experience,  but,  as  in 
most  other  instances,  it  had  a  happy  ending.  Two  weeks 
after  the  call,  it  was  gratifying  to  receive  a  small  order  for 
plastics  rulers.  Today  this  same  dealer,  including  his 
branch  stores,  features  a  complete  line  of  plastics  rulers, 
protractors,  stencils,  and  plotting  and  computing  device-. 

In  the  old  days,  resistance  was  always  greatest  where  the 
purchasing  department  was  headed  by  a  woman.  Today, 
however,  women  are  more  progressive  and  better  informed, 
so  that  now  we  have  little  difficulty  on  that  score.  Of  in- 
terest, too,  is  the  fact  that,  although  these  plastics  devices 
were  a  "natural"  for  office  supply  stores  and  drawing  sup- 
ply distributors,  it  was  often  easier  to  create  buyer  interest 
in  such  isolated  fields  as  hardware  or  photo  supply  h< 
At  present,  however,  although  the  latter  stores  still  do  a 
sizeable  business  in  plastics  instruments,  the  former  types 
of  stores  are  markedly  anxious  to  carry  them.  In  depart- 
ment stores,  which  have  also  readily  adopted  plastics  in- 
struments, these  devices  are  sold  in  several  different  dcpart- 


50 


AUGUST  1946 


ments,  such  as  tool  room  supplies,  drafting  supplies,  and  ar- 
tists' supplies.  A  further  significant  indication  of  the  in- 
roads now  being  made  is  that  during  the  war — a  time  when 
all  drawing  instruments  were  at  a  premium — one  of  the 
large  wooden  ruler  manufacturers  closed  up  shop. 

Foreign  Demand 

The  great  demand  abroad  is  no  less  significant  than  the 
demand  at  home.  Our  first  advertising  prospectus  sent  to 
Latin  America,  which  described  a  plastics  T-square, 
brought  in  orders  from  every  Latin  American  country. 
Recently  one  European  country  ordered  11,000  plastics  slide 
rules.  Whereas  formerly  buyers  sought  for  "Made  in  Eng- 
land" or  "Made  in  Germany"  as  a  guarantee  of  highest 
quality  in  instruments,  now  "Made  in  U.S.A."  commands 
greater  respect  and  has  more  pulling  power. 

A  visit  to  the  classroom  reveals  students  using  plastics 
instruments  in  the  laboratory,  manual  training  room,  and 
"math"  class.  A  call  on  a  photographer  discloses  that  he 
prefers  transparent  plastics  ruling  devices  for  making 
measurements  on  the  camera  ground  glass,  as  well  as  for 
retouching,  photostat,  and  enlarging  work. 

Doctors,  medical  students,  X-ray  technicians,  and  scien- 
tists find  transparent  plastics  instruments  indispensable  in 
their  specialized  work.  The  drafting  room  is  stocked  with 
plastics  straight  edges,  protractors,  T-squares,  and  other 
time-saving  plastics  devices.  Thousands  of  plastics  draw- 
ing instruments  have  served  the  armed  forces  in  anti-air- 
craft training,  reconnaissance  work,  target  location,  map 
reading,  and  naval  radio  technical  training.  At  flight 
schools  trainees  use  plastics  plotters  and  computers  for 
solving  many  navigational  problems. 

During  the  war  dealers  found  it  difficult  to  keep  their 
stock  fully  checked  because  of  a  clerk  shortage.  In  addi- 


tion, manufacturers'  representatives  could  not  make  peri- 
odic calls  on  account  of  travel  conditions.  Thus,  dealers' 
stocks  became  sadly  depleted.  Yet  by  that  time  plastics  de- 
vices had  gained  such  wide  acceptance  among  consumers 
that  they  themselves  often  wrote  directly  to  the  manufac- 
turer for  items  they  wanted. 

Another  unusual  indication  of  their  interest  is  the  novel 
and  unanticipated  applications  to  which  they  put  the  instru- 
ments. One  man  placed  a  transparent  ruler  over  a  signa- 
ture to  measure  letter  formation  and  spacing  in  a  suspected 
forgery.  A  manufacturer  used  it  in  measuring  and  mark- 
ing candy  caramels,  advantages  being  that  it  can  be  washed 
and  thus  kept  sanitary  and  that  the  lamination  keeps  the  let- 
tering from  coming  off. 

A  teacher  prefers  plastics  rulers  because  they  do  not  clat- 
ter and  bang  when  her  students  drop  them  on  the  floor.  An 
accountant  praises  his  plastics  ruler  because  the  flexibility 
of  the  material  allows  him  to  use  the  ruler  over  the  curved 
pages  of  the  ledger. 

Inventors  Offer  Their  Ideas 

The  interest  in  plastics  has  given  rise  to  many  creative 
and  inventive  offerings.  Many  ideas,  both  patented  and 
non-patented,  are  constantly  being  offered  for  manufacture 
and  distribution  on  some  profit-sharing  basis.  The  flow  of 
inventive  ideas  comes  from  small  towns,  as  well  as  metro- 
politan areas.  In  one  instance  a  young  man  in  California 
submitted  for  consideration  a  calculator  at  almost  the  same 
time  as  an  army  sergeant  from  Massachusetts  submitted  the 
identical  idea.  Both  plans  were  presented  with  patent-pend- 
ing markings  and,  although  the  calculator  seemed  to  have 
merit,  it  was  not  considered,  because  of  the  conflict  that 
might  have  arisen.  Recently  a  professor  in  a  South  Ameri- 
can country  made  it  known  that  he  had  a  useful  plastics  de- 


Plastics  drawing  devices  are  favored  by  the  public  because  they 
weigh  little,  last  long,  save  time,  and  permit  full  visibility 

Adjustable-angle  T-square  doubles  as  protractor.  Rule  at  right  has  symbols  for  drawing  circuit  diagrams 


Dotted  line*  on  architectural  drawing  were  made  by  pas- 
ting a  pencil  over  the  perforations  oi  the  "Spee-Dotter" 


Conversion  graph  on  face  of  aerial  navigation  instrument 
give*  true  airspeed,  wind  velocity  and  many  other  values 


vice,  and  was  willing  to  part  with  it — provided  only  that 
funds  were  made  available  for  his  transportation  to  the 
I'nited  States! 

While  many  ideas  are  not  practical  and  some  are  prohib- 
itive to  produce,  many  useful  instruments  are  acquired. 
One  of  these  is  the  Spee-Dotter,  a  recently  patented  draft- 
ing instrument  which  facilitates  the  work  of  draftsmen,  ar- 
chitects, and  engineers  by  making  it  possible  to  produce 
accurately  dotted  lines  of  alternate  dashes  and  dots,  and 
lines  made  up  of  dashes  followed  by  two  dots.  The  ma- 
chine-like precision  of  the  dotted  lines  results  from  simply 
drawing  a  pen  or  pencil  across  a  series  of  perforations  on 
a  cellulose  acetate  sheet. 

Ideas  are  still  pouring  in  daily.  The  very  air  seems  to  be 
charged  with  interest  in  plastics.  Now  that  the  war  is 
over  and  plastics  materials  will  probably  soon  be  available 
in  adequate  quantities,  we  shall  witness  many  improvements 
in  the  design  and  usefulness  of  plastics  drawing  in-tm- 
mcnts.  Our  own  files  are  filled  with  drawings  and  data  on 
items  to  come.  These  are  the  result  of  close  study  of  the 
tools  needed  for  better  and  more  efficient  work.  There  are 
many  factors  favorable  for  converting  from  wood  and  metal 
(Continued  on  page  78) 


•C-Thru"  Plastics  Drawing  Instruments 


Instrument 


Material 


Comments 


B-70  Ruler,  2'  by  12'..  .Cellulose  nitrate. 


R-700  Protractor  Rule 

with  electronic  symbols. .  .Cellulose  nitrate. . 

P. 400  Photo  Map  Co- 
ordinate Scale Vinyl  co-polymer. 


No.  27  Slide  Rule Vinyl  co-polymer. 


AT-8  Adjustable  Triangle .  Cellulose  nitrate . 


T-28  Calibrated  Triangle. Cellulose  nitrate. 


No.  1  2  Spee-Dotter 

and  Refills Vinyl  co-polymer . 


P3-900  Computer Vinyl  co-polymer. 


B-95  Ruler,  2*  by  18' Vinyl  co-polymer. 


TS-I  18  T-Square. 


Adjustable  triangle  (lower  right  corner)  and  the  plot  and 
map  co-oi dtnale  teal*  were  used  by  Army  lot  map  ttudy 


.Vinyl  co-polymer 
arm;  acrylic  head . 


.  Special  ruling  and  the  trans- 
parency of  material  permit 
measuring  and  ruling 

.  Transparency  permits  angle 
finding,  circuit  building 

.Used  for  map  reading  and 
aerial  photography.  Vinyl 
co-polymer  gives  the  de- 
sired stability 

.Light  and  easy  to  carry. 
Transparent  and  opaque 
vinyl  laminated  for  perma- 
nency of  printing 

.A  time  saver  in  the  drafting 
room.  Here  ogai  n,  trans- 
parency leaves  no  blind 
spot  on  the  tracing  or  blue- 
print paper 

.Special  rulings  combined 
with  transparency  permit 
drawing  parallels  and  per- 
pendiculars, plotting  charts, 
and  laying  off  angles 

.  The  flexibility  of  the  mate- 
rial, its  shaping  and  form- 
ing permit  interchangeable 
refills  to  snap  on  easily. 
Economy  in  piercing  open- 
ings, results  in  a  highly  time- 
saving  instrument  at  nominal 
cost 

,  .  The  combination  of  trans- 
parent and  opaque  plastics 
makes  it  possible  for  one 
instrument  to  perform  many 
calculations,  thus  eliminat- 
ing the  use  of  several  In- 
struments 

.  .  Special  rulings  combined 
with  transparency  permit 
viewing  comparative  meas- 
urements between  English 
and  metric  scales  when 
placed  over  area  where 
needed  readings  are  to  be 
made 

. .  Acrylic  head  can  accommo- 
date different  length  arms 


f  LAST  it'S 


1016 


THERE'S   MORE 
TO  SEE 
THAN   MEETS 
THE  EYE 


' 


npHERE'S  LITTLE  TO  SEE  of  this  Zenith  hearing  aid  ear  piece.  It  is  small, 
JL  inconspicuous,  beautifully  blended  into  the  flesh  tones  of  the  face  and  ear 
of  the  wearer.  It  is  a  masterpiece  in  the  practical  application  of  Plaskon  Molded 
Color  to  modern  problems. 

Behind  it  is  a  story  of  Zenith  pioneering;  of  helping  to  solve  a  psychological 
problem  resulting  from  a  physical  defect;  of  bringing  to  thousands  of  hard-of- 
hearing  people  an  efficient,  low-cost  hearing  aid  that  graces  the  wearers,  and  opens 
for  them  new  opportunities  in  employment,  entertainment  and  advancement. 
Plaskon  plastic  materials  are  available  in  a  beautiful  range  of  colors    clean,  clear 
tones  that  are  uniform  and  unchanging,  because  they  are  solid,  permanent  color 
through  and  through.  Plaskon  Molded  Color  is  warm  and  friendly  to  the  touch. 
The  gleaming,  non-porous  surface  will 
not  tarnish,  check  or  corrode.  Plaskon 
is  strong,  shock-resistant,  won't  chip 
or  shatter. 

Plaskon  materials  have  distinctive  fea- 
tures that  give  them  widespread  appli- 
cation in  the  electrical,  cosmetic,  drug, 
garment  and   many   other  industrial 
fields.  Write  for  free  illustrated  book. 


MOLDED    COLOR 


PLASKON    DIVISION   •   LIBBEY  •  OWENS  •  FORD  GLASS  CO.    •    2104  Sylvon  Ave.,  Toledo  t,  Ohio   •    Canadian  Agent:  Canadian  Industries,  Ltd.,  Montreal,  P.O. 


UIAL 


Industrial's  staff  of  technical  experts  are  particularly 
qualified  to  discuss  problems  in  the  development 
and  production  of  your  plastic  product.  Their  experts 
know  intimately  from  long  experience  all  phases  of 
the  compression  molding  process.  They  can  assist 
you  in  design,  fit,  finish,  color  and  type  of  material. 
From  deep  draw  units  to  shallow  flat  surfaces  our 
methods  produce  uniformly  high  volume  within 
extremely  close  tolerances.  Whatever  the  nature  of 
your  design  problem,  Industrial's  staff  can  help  you. 
Write  today. 

""  ""*.  -...  «  .....  - 


South  Bend  Representative:  Krueger  Sales  &  Engineering  Co.,  P.O.Box  419,  Soufh  Bend,  Ind. 


The  improved  abrasion  resistance  and 
surface  hardness  contributed  by  the 
resin  constituent  of  the  new  material 
makes  possible  minuteness  of  detail 
in  the  making  of  cast  novelties.  Enam- 
els and  fast-drying  lacquers  can  be 
applied  to  "Hydromite"  castings  in  a 
variety  of  attractive  color  patterns; 
unlike  plaster,  the  new  material  does 
not  have  to  be  sized  before  painting 


JVeur  Mix 
for  Casting 

Gypsum  cement-resin  combination 
is  inexpensive,  easy  to  use,  and 
forms  hard  and  strong  products 


8,  J.  S.  O((M 

Merchandise    Manager,    Industrial    Gypsum,    Lime    &    Paper 
United  States  Gypsum  Company 


A  RECENTLY  developed  product  combining  the 
major  advantages  of  synthetic  casting  resins  and 
gypsum  cements  meets  a  long-time  need  of  industry  for  an 
easily  formed,  quick  hardening  die  material.  Known  as 
Hydromite,  it  is  a  dry  powder  which  requires  only  the  addi- 
tion of  the  proper  amount  of  water. 

The  major  advantages  of  Hydromite  are  that  it  (1)  is 
easy  and  quick  to  mold  and  cast,  (2)  has  less  shrinkage 
than  synthetic  resins,  (3)  casts  and  forms  in  simple,  in- 
expensive molds  and  dies  without  the  use  of  high  cost  shop 
equipment,  and  (4)  has  more  permanently  stable  dimen- 
sions than  most  plastics.  It  is  superior  to  gypsum  cements 
in  toughness,  impact  strength,  surface  hardness,  and  resis- 
tance to  abrasion.  It  is  particularly  advantageous  for  de- 
tailed dies  with  abrupt  contour  changes  because  the  strength 
and  hardness  of  the  material  keep  the  edges  from  wearing. 

Hydromite  was  first  released  in  experimental  quantities 
about  a  year  ago,  and  since  has  found  many  commercial 


applications.  Present  or  potential  uses  are  for  duplicate 
patterns,  models,  forming  dies  or  molds  for  soft  metals  and 
plastics,  molds  for  low-pressure  and  contact  pressure 
laminating,  templates,  jigs  and  fixtures,  masks,  a  variety  of 
cast  novelties,  and  similar  applications  where  easily-formed, 
hard,  resilient,  and  strong  casts  are  required.  A  few  users 
selected  more  or  less  at  random,  with  their  uses  for  the 
material,  are:  Gits  Molding  Co.,  templates  and  fixtures; 
Plastic  Finishing,  Inc.,  masks  for  masking  out  paint  in  the 
finishing  of  plastics  parts ;  Lindberg  Engineering  Co.,  in- 
termediate molds;  and  Owens-Corning  Fiberglas  Corp., 
molds  for  experimental  low-pressure  and  contact  pressure 
laminating. 

In  the  aircraft  tooling  field,  Hydromite  is  used  for  hydro- 
press  dies,  stretch  forms,  router  forms,  shapes,  check  fix- 
tures, drill  jigs,  templates,  and  assembly  fixtures. 

A  use  has  also  developed  in  the  costume  jewelry  field.  A 
variety  of  designs  can  be  used  in  making  pins,  clips,  and 
ear-rings.  The  desired  clasp  or  fastener  can  be  inserted  in 
the  article  while  it  is  hardening,  thus  eliminating  the  gluing 
operation  necessary  when  other  materials  are  used. 

Hydromite  is  also  being  used  in  medallions,  wall  plaques, 
and  statuary.  Its  toughness  eliminates  much  of  the  shelf 
chipping  to  which  most  statuary  is  subject  and  thus  mini- 


AUGUST  1946 


1'LASTICS 


55 


nnzes  retailer  In-..-..  It  does  not  have  the  |x>tential  breakage 
of  ceramic  object  - 

The  formed  material  offers  an  excellent  painting  surface 
and  readily  accepts  enamels  and  fast  drying  lacquer-.  No 
sizing  is  required  a>  it  is  when  pla-tcr-  are  used.  After 
allciwing  the  material  to  dry,  the  lacquer  may  l>e  sprayed 
on  immediately  ami  dries  within  a  few  minutes.  This 
afford-  a  speedy  output  and  a  lower  production  cost. 

One  of  the  most  interesting  uses  which  Hydromite  has 
found,  is  in  the  preparation  of  dies  from  which  tantalum 
skull  restorations  are  niade.  Because  of  the  numerous  skull 
injuries  during  the  war,  the  problem  of  making  dies  for 
skull  rejKiir  is  very  important.  Tantalum  skull  plates,  made 
from  Mat  sheets,  may  IK-  hammered  or  beaten  by  hand  in 
form  the  desired  contour.  It  takes  approximately  two 
hours,  however,  to  swage  a  plate,  while  with  H ydromitc 
dies  it  takes  nnly  about  20  min  to  shape  the  same  plate 
more  accurately  than  can  IK-  done  bv  hand.  Also  stellic 


cracks  and  breakdown  at  the  edges  of  the  skull  plate-  are 
avoided. 

Another  interesting  use  is  for  the  shell  over  rubber  latex 
molds,  which  backs  up  the  mold  in  the  proper  position  and 
keeps  the  dimension-  accurate  and  j>ermits  rough  handling 
of  the  mold  when  removing  entrapped  air  and  surface  bub- 
Mi--.  Not  only  is  Hydromite  used  for  the  shell,  but  al-o  ir 
forming  the  latex  strip  molds  themselves. 

The  new  material  has  also  been  used  as  a  mold  for  th< 
casting  of  thermosetting  resin-.  When  this  is  done.  th« 
mold  i-  coated  to  protect  it  from  the  acid  catalyst  "i  tin 
resin. 

An  application  in  the  aircraft  industry  will  serve  to  illuv 
Irate  further  the  method  of  use  of  the  material  and 
\antages  for  industrial  tooling.  At  one  of  the  large  aircraf 
producer-  it  was  the  practice  to  make  hydropress  die-  o: 
metal  to  insure  a  long  production  life.  It  frequently  de 
(Continued  on  page  81) 


Alter  exact  portions  are  measured  out.  the  powder  i»  spread  on  the  water  and  worked  in  with  a  confectioner's  wire  whip 
to  form  a  smooth  and  well-blended  mix.  There  in  insufficient  water  to  wet  the  powder  satisfactorily  merely  by  soaking 


After  a  thorough  stirring,  the  blended  mix  IB  poured  Into  the  mold  in  a  thin  stream  to  that  the  air  inclusions  of  the 
mix  are  broken.  The  set  casts  ate  removed  (right)  by  flexing  the  mold.  The  backs  have  been  screeded  to  make  them  flat 


.-,6 


I'I..\STU  • 


\\  <;i  ST 


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CHARM 

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vited to  submit  samples  for  expert  deco- 
rating recommendations. 


Executives:  Send  for  this  new 
Decal    Decoration    Catalog. 
(Firm  letterheads,  please) 


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Stock  designs  are  avail- 
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Exclusive  designs  can  be  pro- 
duced to  specifications  on  request. 
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MEYERCORD  CO 


World's  Largest  Deco/comonia  Manufacturers 
5323      WEST      LAKE     STREET      •       •      •       CHICAGO     44,     ILLINOIS 


AUGUST  1946 


PLASTICS 


57 


Opportunities 
in  Costume 
Accessories 


Influence  of  cm  earlier  period  of  history  is  apparent  in 
the  delicately-executed  design  of  a  modern  head-covering 


Flexible  choker  and  distinctive  lapel  ornament  are 
assembled  from  many  separate,  injection  molded  units 


Supplying  a  new  medium  for  the  creativeness  of  designers,  plastics 
provides  exciting  and  variegated  style  and  material  possibilities 


_Ja/ia< 


\erS 


ASSOKIKS  fur  tVniininc  adornment  are  not  a  new 
development,  for  their  origin  is  obscured  in  antiquity. 
As  far  l>ark  as  we  arc  able  to  trace  historical  and  racial 
customs,  it  seems  to  have  been  somewhat  general  practice 
tor  women  (and  men,  too,  in  many  ages)  to  enhance  their 
personal  appearance  by  means  of  costume  accessories.  In 
the  modern  phases  of  this  field,  plastics  assumes  a  prominent 
loir.  bringing  to  designers  new  materials  and  style  possi- 
bilities for  these  items. 

As  an  example,  consider  one  of  the  most  ancient  of  adorn- 
ment-.— the  ornamental  comb.  ( Y//II/HU/  (cellulose  nitrate  I 
made  feasible  the  development  of  new  design  and  style  in 
ornamental  comt>s.  and  was  followed  in  time  by  other 
colorful  plastics,  including  the  acetates,  hutyratcs.  acrylics. 
polystyrene. 

The  accompanying  sketches  show  :i  nnmlx-r  of  the  au- 
thor's designs  for  li  in  which  the  versatility  and 
adaptability  of  plastics  are  displayed.  I'irst  illustrated  is 
an  unustiai  method  of  combining  the  function  of  comb  and 
•ing.  Meant  to  In-  a  i  .  nnpr<  .mi  -r  between  com- 
plete hatlcssnc-s  and  the  "dressv"  tvpe  of  hat.  it  is  designed 


to  tempt  the  woman  who  may  be  succumbing  to  the  ten- 
dency (deplored  by  milliners)  of  going  without  a  hat  on  all 
occasions. 

Injection  molded,  shell-thin,  and  in  a  delicately  carved 
scroll  design,  this  item  is  made  to  conform  snugly  to  the 
head  contours  and  appear  as  an  integral  part  of  the  hair- 
style. Butyrate  suggests  itself  as  a  likely  material  to  ac- 
company a  tailored  costume,  while  acrylics  might  be  used 
for  a  "comb-head-covering"  of  a  more  elaborate  design  for 
formal  wear.  With  outdoor  costume,  a  matching  scarf  or 
bird-cage  veil  (as  shown  in  the  illustration)  is  attached, 
supplying  a  finished  look  to  the  ensemble.  It  does  away 
with  the  feeling  and  appearance  of  incomplete  attire  that 
accompanies  hatlessness. 

The  second  sketch  illustrates  adaptation  of  a  necklace 
unearthed  from  an  Kgyptian  tomb.  In  its  modern  \< 
it  is  a  flexible  and  comfortable  to-wear  choker,  of  plas- 
tics— perhaps  an  acrylic  such  as  I'le.riglas.  The  moderniza- 
tion of  the  exquisite  design  of  the  necklace  has  IK-CII 
achieved  without  changing  its  principle  of  structure.  The 
choker  is  comprised  of  many  separate  units,  injection 
molded  and  cleverly  assembled.  The  idea  of  "sepaiate  units" 
coincides  perfectly  with  present-day  economy  in  manufac- 
turing. The  product  designer  must  rcmemltcr  the  high 
mold  costs  versus  the  com|>arativcly  Meeting  life  span  of 
any  fashion  article.  Much  time  anil  money  are  required  to 


H 


I'l.  \STIt  S 


AUGUST  1946 


build  molds — and  fashion  trends  are  too  often  "here  today 
and  gone  tomorrow."  It  is  therefore  necessary  to  plan 
constructively  to  meet  the  contingency  of  quick  fashion 
changes — such  as  the  possibility  of  the  long  necklace  sud- 
denly supplanting,  in  favor,  today's  extremely  popular 
choker. 

In  the  case  of  separately  assembled  units,  that  would  not 
be  a  serious  matter,  for  these  sections  are  made  to  dovetail, 
and  lend  themselves  to  countless  rearrangement.  Accord- 
ingly, out  of  a  collection  of  as  few  as  four  or  five  different 
sizes  and  styles  in  units,  numerous  pieces  can  be  evolved. 
The  center  semi-spherical  unit  shown  in  the  sketch  can  be 
utilized  for  individual  rings  or  earrings,  the  smaller  units 
alternated  with  larger  ones,  and  so  on. 

Shown  in  the  same  sketch  is  an  individual  unit  assembled 
by  means  of  a  gold  mounting  into  an  attractive  lapel  orna- 
ment or  dress  clip.  Here,  the  combination  of  materials 
serves  to  enhance  the  jewel-like  beauty  of  the  plastics,  giv- 
ing it  individuality  and  outstanding  appearance. 

Little,  if  anything,  of  consequence  has  been  done  to  glam- 
orize the  utilitarian  umbrella,  either  in  form  or  construc- 
tion, since  the  first  drastic  change  from  bamboo  ribs  to  steel. 
The  author  has  designed  a  swagger,  over-the-shoulder-strap 
umbrella,  easy  to  carry,  leaving  hands  free  for  handbag  and 
sundry  parcels.  It  is  shown,  in  two  accompanying  sketches, 
as  it  looks  when  open  and  when  closed. 

The  ribs  are  outlined  in  scintillating,  injection  molded 
plastics  cabochons  individually  applied  to  the  fabric  cover- 
ing in  order  to  retain  full  flexibility.  When  the  umbrella 
is  closed,  the  cabochons  move  close  together  and  side  by 
side,  thus  presenting  a  unique  and  almost  unbroken  plastics 
surface.  The  bright,  gleaming  mateiral  is  in  the  same  high 
color  as  the  rayon  taffeta  covering,  to  inject  a  cheery  note 
into  a  rain-threatening  day.  Handle  and  ferrule  are  also  of 
bright-colored  clear  plastics  to  match  the  covering  and  the 
strap  is  stitched  of  this  material.  Strap  is  equipped  with 
two  snap  hooks  which  fasten  to  either  end  of  the  umbrella. 
When  tlie  umbrella  is  in  use,  the  strap  can  be  detached, 
wound  into  a  tight  coil  and  suspended  from  handle,  out  of 
the  way. 

A  handbag  similarly  decorated  with  plastics  cabochons  ap- 
pears in  another  sketch.  This  styling  is  a  throw-back  to 
ancient  times  and  still  is  one  of  the  most  convenient  of 
all  handbag  designs.  The  pouch  bag  opens  wide,  by  means 
of  the  ingenious  gatetop  which  pulls  out  far  enough  to 
show  the  inner,  zippered  pockets  and  contents,  and  can  be 
closed  up  tight,  remaining  firmly  in  position  under  the 
molded  plastics  cap.  It  has  a  "dressmaker"  softness,  de- 
sirable in  some  types  of  handbag,  yet  possesses  sufficient 
rigidity  to  make  handling  easy.  The  firmness  is  acquired 
by  means  of  the  plastics-studded  surface  and  this  treatment 
of  plastics  "ties-in"  the  bag  for  complete  ensemble  effect 
and  gives  the  rainy  day  costume  a  new  interest.  In  these 
last  three  items,  polystyrene  or  the  acrylics  might  be 
thought  most  desirable. 

In  various  adaptations,  belts  have  remained  one  of 
fashion's  recurrent  requisites.  Simplicity  in  dress  design 
today  calls  for  a  concentrated  touch  of  some  ornamentation, 
for  which  the  belt  supplies  a  perfect  medium.  The  whole 
range  of  thermoplastics  can  have  a  play  in  this  appealing 
application,  with  the  jewel-like  acrylics  and  polystyrenes  in 
the  lead,  and  cellulose  acetates  and  vinyls  a  close  second. 

The  belt  shown  in  sketch  is  made  of  cellulose  acetate 
injection  molded  cabochons  in  tortoise  shell  color.  These 
gleaming,  sharply-faceted  cabochons  are  provided  with  slots 
through  which  the  fabric  or  leather  bands  pass  to  fasten 
with  a  plastics  buckle. 

This  application  is  intended  for  sports  or  tailored  wear 
but  can  be  carried  out  in  more  decorative  manner  by  use 
of    finely    hand-faceted    acrylics   or    metal-plated    cellulose 
(Continued  on  page  93) 


Ingenious    application    of    colorful    plastics    transforms    a 
rainy-day  necessity  into  an  attractive  accessory,  as  well 


When  umbrella  is  closed,  its  decorative,  sparkling  cabochons 
move    close    together,    presenting    a   brilliant,    unique    surface 


AUGUST  1946 


PLASTICS 


59 


"Air  Ku»hon»"  produced  by  Du  Page 
Plastics  Co..  Chicago,  ol  sturdy,  trans- 
parent vinyl  plastics,  are  ideal  for 
many  uses.  Easily  inflated  and  de- 
flated, convenience,  smart  appear- 
ance and  lightness  of  weight  are 
among  their  qualities.  Mattress 
made  ol  several  of  these  "Kushons" 
laced  together  provides  comfortable 
means  for  relaxation  at  the  beach 


Impregnation  of  any  type  ol  fabric  with  cellulose 
acetate  is  basis  lor  colorful,  durable  lampshades 
such  as  this  produced  by  Empire  Shades.  Inc..  N.  Y. 


fill 


Plastics  fan.  featured  In  a  Paramount  Popular 
Science  "short."  is  designed  to  protect  fingers 
ol  absent  -minded  handlers.  Built  like  a  tur- 
bine, it  generate*  a  cocl.  refreshing  breeze 


"Teen-timers"  raincoats  for  girls  are  made 
of  nylon,  calendered  by  Aldan  Rubber  Co., 
Philadelphia,  with  vinyl  butyrate  compounds. 
Weighing  only  12  ounces,  these  smart  coats 
are  available  in  five  gay,  attractive  colors, 
with  matching  hats  and  detachable  hoods 


V 


Utilization  of  cellulose  in  the  field  of  wear- 
ing apparel  is  smartly  emphasized  in  gar- 
ments such  as  this  trimly-styled,  easy-to-wear 
"pedal  pusher"  ensemble  of  black  rayon 
gabardine,  designed  by  Louise  Ballerina 


Yardley  Plastics  Co.,  Columbus,  O.,  extrusion  molds 
draftsmen's  splines  of  transparent  "Tenite."  High  di- 
mensional stability  assures  molding  to  close  tolerances 


Assortment  of  shapes  suggests 
the  fanning  possibilities  with 
Fiberglas-reiniorced  melamine 
laminates.  Among  the  strongest 
and  roost  indestructible  of  ma- 
terials, including  the  metals, 
their  biggest  advantage  may  be 
in  the  weight  saving  they  offer 


Glass  Fabric  Melamine 
Resin  Laminates 

New-type  engineering  material,  already  established  in  many  electrical 
uses,  possesses  unexplored  potentialities 


C.       . 


Development  Engineer,  Micerte  Divition 
Wettinghoute    Electric    Corporation 

ALTHOUGH  synthetic  resin  condensation  products  of 
phenol  and  formaldehyde,  and  urea  or  thiourca  and 
formaldehyde,  have  been  manufactured  in  large  quantities 
.1  period  of  years,  it  is  only  recently  that  synthetic 
condensation  products  of  mc-lamine  and  formaldehyde  have 
gained    considerable     iiii|N>rtance.      These    new    synthetic 
are  externally   similar   to  the   urea   resins  but   have 
gained  in  popularity  mainly  because  they  are  practically 
colorless  and  arc  ntorc  water  resistant  and  heat  resistant 
than  urea  formaldehyde  condensation  products. 

Like  phenol  or  urea  resins,  the  mclamine  resins  are  quite 

brittle  and   it  is  necessary  to  reinforce  them  to  produce 

useful   products.     When  Fiberglas  fabric   is  used  as  the 

reinforcement,  products  of  very  high  strength  are  produced. 

B'-fore  the   war,  melamine  restn-.   in   combination   with 


pigments,  were  used  tn  make  paper  base  laminates  t, 
decorative  applications.  Since  then,  they  have  been  use 
in  aircraft  ignition  parts  Ixvanse  of  their  combination  c 
good  electrical  insulating  qualities,  anil  high  degree  of  ar 
and  heat  resistance :  and  are  now  used  as  panel  boards  fo 
electrical  equipment  because  of  their  good  arc.  flame  an 
-hock  resistance. 

Nature  of  Melamine  Resins 

Melamine,  the  t>a-c  material  from  which  these  re-nis  ar 
made,  is  produced  from  calcium  cyanamide,  the  product  < 
fixation  of  atmospheric  nitrogen  with  coke  and  linn 
Chemically,  melamine  may  be  defined  as  2,  4,  6-triamine  -' 
3,  5  tria/ine  which  points  out  the  comm'ttp  conception  of  il 
structure  and  shows  its  resemblance  to  tit  benzene  nucleu 
Melamine  crystalli/c-  from  water  solutions  in  colorles 
prisms  with  a  melting  point  of  354°  C. 

The  initial  reaction  of  melamine  and  formalileliyilc  re-nil 
in  the  formation  of  methylol-melaniine  compounds  which  ar 
-till  crystalline  When  the  reaction  is  allowed  to  continui 
it  may  proceed  in  two  different  ways:  the  formation  of  a 


PLASTICS 


At  (Jl  ST 


ether  bonding,  with  water  being  split  off;  or  the  formation 
of  a  methylene  bonding  between  two  NH2-groups,  water 
and  formaldehyde  being  split  off.  Actually,  both  these 
reactions  take  place  simultaneously.  The  material  has  now 
lost  its  crystalline  nature  and  is  resinous. 

As  the  number  of  combined  triazine  groups  increases,  a 
large  molecule  is  developed  in  three  directions;  and,  when 
a  high  degree  of  polymerization  is  reached,  there  is  formed 
a  combination  in  all  directions  of  space  similar  to  the  ar- 
rangement in  phenol-formaldehyde  resins. 

The  actual  manufacturing  procedure  for  laminating  type 
tnclamine  resins  consists  of  reacting  melamine  and  formal- 
dehyde in  the  presence  of  a  catalyst  and  heat  in  an  auto- 
clave until  a  medium  degree  of  polymerization  is  reached. 
(The  resinous  material  is  still  soluble  and  fusible.)  On 
cooling  to  room  temperature,  the  melamine  resins  thus 
formed  are  ground  to  a  fine  powder  and  can  be  easily  stored. 
A  solution  of  the  resin  powder  is  applied  to  the  glass  fabric, 
the  solvent  removed,  and  the  coated  sheets  are  ready  for 
laminating.  The  coating  process  further  reacts  the  resin 
so  that  it  is  less  soluble  but  still  fusible.  The  polymerization 
is  then  completed  by  heat  during  the  molding  process,  and 
the  melamine  resin  is  then  insoluble  and  infusible. 

The  type  of  melamine  resin  solutions  used  for  making 
laminates  change  rapidly  in  viscosity.  This  change  is  much 
faster  than  that  of  an  unmodified,  general  laminating  type 
phenolic  resin  solution.  Melamine  resins  are  also  char- 
acterized by  having  an  indefinite  gel  end  point,  differing  in 
this  respect  from  phenolic  resins,  which  have  a  sharp  gel 
point.  This  difference  gives  the  melamine  resin  some  ad- 
vantage over  the  phenolic  resin  during  the  molding  process 
— melamine  laminates  can.be  brought  to  the  cure  tempera- 
ture without  the  required  temperature  equalization  necessary 
for  phenolic  resins. 

Nature  of  Glass  Fabric  Filler 

The  reinforcement  used  in  these  laminates  is  a  plain 
weave  glass. fabric,  .007"  in  thickness,  weighing  approxi- 
mately six  ounces  per  square  yard  and  having  a  tensile 
strength  of  300  Ib  in  the  warp  and  200  Ib  in  the  filler 
direction.  This  fabric  is  woven  with  42  yarns  in  the  warp 
direction  and  32  yarns  in  the  filler  direction.  These  yarns 
consist  of  three  strands  with  each  strand  being  made  up  of 
approximately  200  continuous  glass  filaments,  .00028"  in 
diameter,  which  are  obtained  by  mechanical  drawing  from 
molten  glass  spheres.  These  spheres  which  are  compounded 
to  give  the  optimum  in  electrical  and  physical  character- 
istics are  relatively  free  of  alkali  oxides  and  possess  excel- 
lent high  temperature  resistance. 

In  making  glass  yarns,  a  small  amount  of  lubricant,  which 
consists  of  a  mixture  of  starch  and  vegetable  oil,  is  added  to 
the  filaments  to  minimize  the  friction  between  fibers  and  to 
lessen  fiber  breakage  and  self-abrasion.  The  lubricant  in  the 
fabric  influences  the  adhesion  of  the  melamine  resin  to  the 
glass. 

While  the  lubricant  may  be  removed  by  chemical  means, 
the  usual  practice  is  to  employ  heat  in  the  form  of  infra-red 
radiation,  gas-heated  metal  rolls,  or  direct  gas  flames.  All 
of  these  methods  tend  to  vaporize  the  oil  and  carbonize  the 
starch,  changing  the  color  of  the  fabric  to  various  shades 
of  brown,  depending  on  the  severity  of  the  treatment. 

While  this  procedure  increases  the  adhesion  of  melamine 


Strength  of  "Fiberglas" 

Yarn  Fabric 


Laminate 


Actual  tensile  strength  (psi) 7.1 320 35,000 

Calculated  tensile  strength  (psi)  .8.2 480 55,000 


TO   PRODUCT   IN    PLASTICS 


'.  .  .  and,    now    we    present 


THE  PLASTIC  PERFECTIONIST" 

"In  conclusion,"  says  Felsy,  who  believes 
in  short  speeches,  "I  want  to  thank  all  of 
you  for  the  wonderful  cooperation  you 
have  given  the  Felsenthal  Organization 
during  the  difficult  years  just  past.  .  .  . 
And  to  promise  increasingly  finer  service 
in  the  years  ahead."  .  .  . 

With  a  heart  pure  as  lucite,  skills  as 
flexible  as  Cellophane,  and  prices  lower 
than  the  melting-point  of  latex,  our  new 
trade-character  "Felsy"  will  meet  you  in 
these  pages.  .  .  .  Watch  for  htm.  .  .  .  He 
will  have  many  messages  of  timely  inter- 
est Tor  everyone  whose  problems  involve 
injection  molding,  plastic  laminating,  or 
fabricating. 

Write  JOT  booklet  3-A  on  your  letterhead 


FELSENTHAL 
PLASTICS 

G.   FELSENTHAL   &   SONS 

4124   W.  GRAND  AVE.     CHICAGO  51,  ILL. 
BRANCH   OFFICES:    NEW   YORK   •    DETROIT 


AUGUST  1946 


PLASTICS 


63 


Machining  Practices  for  "Fiberglas"  Melamine  Laminate 


.  — 

Mexhine  Uted 

T*w 

Is  Used 

Material 

*- 

Peripheral 

Feed 
(in   min) 

Max 
Coolant  Th  of 
MM 

"—  * 

S.i. 

Cut-off 

-;    Vd. 

Carborundum 

16"  dia.  X    Vi' 

.20  Grit 

1  800  rpm 

7500'/niin 

24 

Water     2' 

(towing) 

cut-off  wheel 

thick 

f520l 

Cut-off 

Pollard 

Diamond  wheel 

16"  dio.  X  .064' 

Copper  alloy  & 

1  800  rpm 

7500'  min 

24 

Water     2' 

(lowing) 

diamonds 

Cut-off 

Woodworking 

Carborundum 

12-14'  dia.  X    Vl' 

•  20  Grit 

3400  rpm 

12400',  min 

1  1  '  (hand) 

None*      1' 

(•owing) 

table  saw. 

resinoid 

40'  (hand) 

Vi' 

heavy  duty 

205-C-4X 

C-207-T-BX 

Cut-off 

Stone  take 

(•owing) 

about  tow 

Carborundum 

16'  dio.  X    Vi* 

-60  Grit 

2150  rpm 

9000'/min 

10'  (hand) 

Water     Vi' 

Beveling 

Pollard 

Carborundum 

16'  dia.  X   1  Vi' 

•20  Grit 

1  800  rpm 

7500'/mln 

24 

Water 

wheel  with 

correct  bevel 

D".      r~ 

Drill  preu 

Twist  drill  (best 

1  '  dia.  max. 

Tungsten-carbide 

1720  rpm  for 

1  40'   min 

.004  '/rev. 

None*     2" 

for  drill  jig  work. 

(drill  about  .002" 

tip.  Included 

thicknesses 

(frequent 

using  slip  bush- 

oversize) 

angle  160-180 

J  ;.,    and  un- 

backing off 

ings) 

with  centering 

der.    1  000  rpm 

desirable) 

point.  Clearance 

for  over  W»' 

angle  =    10°. 

thk.  up  to    Vi'. 

Rake   —   zero  or 

500  rpm  over 

slight  negative 

Vi" 

Drill-,, 

Dr.ll  preu 

Straight  fluted  for 

1  "  dio.  max. 

Tungsten-carbide 

1  720  rpm  for 

1  40'   min 

.004  '/TV*. 

None*     2' 

open  work  —  not 

(drill  about  .002" 

tip.   Included 

thicknesses 

tfrequent 

for  drill  jigs 

ovenize) 

angle  160-180 

>->»'  and  un- 

backing off 

with  centering 

der.  1  000  rpm 

desirable) 

point.  Clearance 

for  over  »/i»' 

angle  =  10°. 

thk.  up  to  Vi'. 

Rake  =  zero  or 

500  rpm  over 

slight  negative 

Vi' 

Counterbor- 

Heavy  duty 

Two-lipped  cutters 

Tungsten-carbide 

Approx.  Vi 

Light 

None* 

ing  Sk  coun- 

drill press 

with  1  0    nega- 

Hp 

that  for  drilling 

tersinking 

tive  rake 

De  burring 

Hand  too* 

Variable 

Point  style  60  grain    1  3000  rpm 

1  700'    min 

None* 

Rectangular 

Band  saw 

Band  saw 

'."-12  pitch  blade 

60'  /min. 

1  0  (for  1  ' 

None*     (Min. 

shaped  hole 

("thick 

thk.) 

radius 

50'   min. 

Vi') 

2'  thick 

Milling-slotting 

Universal  fly  cut- 

6' dia 

Tungsten-carbide 

450  rpm 

700'   min 

9-10"  min 

None* 

ter  with  lathe  tool 

tip  lathe  tool  — 

single  tooth 

negative  rake 

Face  milling 

End  mill  cutter 

4-6"  dia 

Tungsten-carbide 

450  rpm 

700'  /min 

20'/min 

None* 

tip  tool 

Planing  and 

Metal  shaper 

Lathe  tool  with 

Tungsten-carbide 

80'  min 

Depends 

None* 

shaping 

and  planer 

10    negative 

tip 

upon  finish 

rake  and  20 

desired 

clearance 

Tapping 

Tap  drill 

4-5  mil  oversize 

High  speed  ni- 

None* 

for  full  thread. 

trated  and  chro- 

Use tap  drill  to 

mium  plated 

give  75'  ;  of  full 

, 

thread 

Sanding 

(a)  50"  wide 

Emery  paper 

Emery  paper 

5  mils     pass 

None*     Vi' 

sender 

24  grit 

on  50"  mch 

Ib)  37'  wide 

40  grit 

2  mils   pass 

sander 

on  37'  mch 

Grinding 

Grinder 

Carborundum 

14'  dia. 

20  Grit 

1750  rpm 

6000  '/'min 

.005  '/  pass 

Water     2' 

wheel 

4'  wide 

carborundum 

brand 

Cenlerlesi 

Carborundum 

16'  dia 

Carborundum 

2700  rpm 

11,  000'  'min 

.005  "pan 

None* 

grinder 

wheel 

brand  resinoid 

(1st)  .002' 

bonded 

(Finish) 

A35  (Ht) 

A50  (Finish) 

Punching 

Punch  preu 

Regular  open 

Min.  clearance  be- 

Tool steel 

90  strokes  per 

Heat  in   ',." 

compound  die 

tween  punch  and 

min 

oven  to 

die 

13S°C 

Shearing 

Shear  presses 

37'  wide 

Steel  blade 

None*    </(.' 

100  'wide 

Steel  blade 

None*    <V 

Treponlng 

Drill  pr.si 

Special  end-type 

3Vi"  max.  O.D. 

Tungsten-carbide 

900  rpm 

850'/min 

.0006'  rev 

None*     Vi* 

cutter.  Inserted 

extension  cutter 

tip 

teeth  clearance: 

lOVi'O.D 

Angle—  30° 

Rake—  7° 

V  ,]^h,nm  -i 

lame 

lathe  tool  with 

Tungsten-carbide 

150-300' 

.002-.003' 

None 

(turning) 

33    clearance 

Hp 

per  min 

per  rev 

and  10    nega- 

tive rake 

*wk*/*  "• 


Etloi,  b*  provided  to  r»mov*  chlpt  and  dull,  om*fwit«  dtrmotifit  may  occur. 
I  en  f  73».7  Mkerte.  FMMte  (MA  or  HCI.  Co.boJo,  (113  or  44A).  and  Vaixolo.  taew.1  I2A5  or  2A3I. 

I'L  \STICS 


AUGUST  1946 


:sin  to  the  fabric,  the  factors  involved  have  not  been  too 
early  defined  and  many  theories  on  the  bonding  have  been 
>rmulated.  According  to  one  of  these  theories,  synthetic 
:sins  do  not  adhere  well  to  glass  fibers  because  the  glass 
is  a  natural  tendency  to  retard  the  cure  of  the  resin.  Fol- 
iwers  of  this  theory  believe  that  a  good  adhesion  can  be 
;hieved  if  the  glass  fabric  is  first  completely  freed  of  its 
ibricant  and  then  sized  with  a  chemical  which  decomposes 
n  heating  to  form  a  weak  acid.  They  say  that,  if  this 
beration  of  acid  is  made  to  take  place  during  the  molding 
peration,  it  will  accelerate  the  cure  of  the  resin  adjacent 
)  the  glass  fibers  and  result  in  better  adhesion. 

Another  theory  maintains  that  after  heat  treatment  jthe 
ibric  has  a  great  affinity  for  water  and  that  the  presence 
F  a  molecular  layer  of  water  prevents  good  bonding.  To 
vercome  the  formation  of  the  water  layer,  it  is  recom- 
lended  that  the  fabric  be  coated  immediately  after  heat 
•eatment. 

A  third  theory  points  out  that  the  presence  of  the  lubri- 
ant  inhibits  resin  pick-up  and  its  adhesion  to  the  glass 
ibric.  Heat  treating  the  glass  fabric  removes  some  of  this 
ibricant  and  results  in  better  impregnation,  which  in  turn 
ives  higher  bond  strength  and  more  satisfactory  physical 
roperties. 

lethod  of  Manufacture 

Since  melamine  resin  solutions  have  a  poor  tank  life, 
ley  are  made  up  just  prior  to  the  fabric  treating  operation, 
'he  usual  practice  is  to  make  up  a  60%  resin  solids  solu- 
on  by  slowly  adding  the  powdered  resin  to  water,  agitating 
igorously  to  facilitate  solubility.  Sufficient  N-butanol  is 
i  added  to  give  a  95%  water,  5%  butanol  ratio.  The 
unction  of  the  butanol,  which  has  a  boiling  point  of  116°  C, 
s  to  lower  the  surface  tension  of  the  resin  solution.  As  it 
aporizes  slowly  during  the  treating  operation,  blistering 
f  the  resin  film  does  not  take  place. 
Control  tests  are  made  on  the  resin  powder  for  gel  time. 
Ul  solutions  before  treating  are  checked  for  pH  values, 
vhich  should  be  between  8.8  and  9.2,  and  for  viscosity, 
vhich  generally  varies  from  60  to  100  centipoises. 

In  the  treating  operation  the  glass  fabric  is  dipped  into 
i  bath  of  the  resin  solution  and  passed  through  squeezer 
•oils,  which  aid  impregnation  and  control  the  amount  of 
:oating.  The  coated  fabric  is  then  run  at  approximately 
10  feet  per  minute  through  a  drying  chamber  maintained 
it  a  temperature  of  about  300°  F  to  remove  the  solvent. 
To  assure  uniformity,  control  tests  are  made  of  the  amount 
ind  flow  of  resin  on  the  coated  fabric.  The  amount  of  resin 
is  measured  by  determining  the  ratio  of  the  weight  of  a 
;ix-jnch  square  sample  of  treated  fabric  and  the  weight  of 


s 


-50         -25 


50 


75 


tOO        IZS 


175        200 


Effects  of  temperature  change  on  the  tensile  strength 
of  glass-fabric  reinforced   melamine   resin  laminates 

AUGUST  1946 


Heat   treating   cloth   in   gas-fired    oven   burns   off   or   cara- 
melizes   sizing,    resulting    in    better    glass    to    resin    bond 


Note  the  suction  ducts  for  removing  the  dust  raised  by 
drilling.  Backing  must  be  used  under  panel  to  give  clean 
holes  on  the  reverse  side.  Below,  melamine  sheet  clamped 
firmly  into  place  is  being  cut  with  a  carborundum  wheel 


65 


/ 


HUT  TxeArco  frame 

FAMX/C 


001      .009      .003       .00*       005        .006      -OO7       .OO6      .009 


Slreu  ilrain    ratio   varies   somewhat   with   fabric   treatment 


untreated  fabric  of  the  same  size.  The  amount  of  drying  is 
controlled  by  measuring  the  flow  of  resin  by  the  parallel 
plate  method.  In  this  test  three- inch  square  layers  of  the 
treated  fabric,  weighing  a  total  of  15  to  20  gm,  are  placed 
in  a  hot  press  between  steel  pressing  plates  and  pressed  at 
1000  psi.  After  five  minutes  the  piece  is  removed  from  the 


160 


120 


too 


1+iftnocouri.f 

_/ 


T 


LAHIMTI 


10 


20 


JO         40 

TlMt     IH 


SO 


60          70 


80 


Comparison  of  Melamine  Resin  Glass  Fabric  Laminates 


Lubricated 
Glass  Fabric 


Heat  Treated 
Glass  Fabric 


Specific  gravity 2.0 2.0 

Tensile  strength  (psi) 28,000 35,000 

Flexural  strength  (psi) 

Flatwise 20,000 88,000 

Edgewise 28,000 60,000 

Compressive  strength  (psi) 

Flatwise 80,000 

Edgewise 1 1,000 

I  Jfod  impact  strength  (ft-lb   in.) 

Flatwise 32 

Edgewise 20 

Bond  strength  (Ib   1  '  ,    thickness) 900 

Arc  resistance  (sec) 1  80 

Dielectric  constant  ( 1  me) 5.2 

Power  factor  ( 1  me) 1.4 

Dielectric  strength  (v   m,  perpendicular 
to  laminations) 

Short  time 350 

Step  by  step 225 

Water  absorption  ('  ,    weight  increase 
24  hr  at  25°  C) 

3  by  1   by  '/, 1.0 

3  by  1  by  V4 0.6 

Dielectric  strength  (v   m,  parallel  to 
laminations) 

Short  time 40 

Step  by  step 35 


98,000 

1  3,000 

24 

14 

1 600 

1 87 

5.9 

1.1 


400 
300 


1.3 
0.8 


45 

40 


press,  the  excess  flow  removed,  and  the  sample  weighed. 
The  flow  is  then  expressed  as  the  percentage  loss  in  weight. 

Several  rolls  of  the  coated  fabric  are  cut  at  the  same  time 
on  a  rotary  cutter  into  sheets  37"  by  74"  or  50"  by  100". 
In  making  up  assemblies,  the  sheets  are  laid  up  in  piles  of 
definite  weight  corresponding  to  the  thickness  desired,  and 
placed  between  steel  pressing  plates.  Thick  panels  are  made 
up  one  in  a  set,  but,  if  less  than  J4"  thick,  several  panels 
are  assembled  in  a  set  and  separated  by  metal  sheets.  A 
1/16"  thick  kraft  paper  pad  backed  up  by  a  steel  plate  is 
used  on  each  side  of  the  sets  to  assure  pressure  uniformity. 
These  assembled  sets  are  then  placed  between  heated  platens 
of  a  multiple  opening  hydraulic  press  and  pressed  at  1100 
psi.  Curing  temperature  is  155°C  with  the  curing  time  ad- 
justed to  the  amount  of  material  so  that  the  panels  are  kept 
at  the  curing  temperature  for  a  half  hour,  after  which  they 
are  stripped  from  the  sets  and  measured  for  thickness  and 
appearance. 

If  the  molded  panels  are  within  the  required  thickness 
tolerance,  they  are  ready  for  trimming.  Property  control 
test  specimens  are  cut  from  each  lot  of  panels  for  resin  con- 
tent, bond  strength,  flexural  strength,  and  insulation  resis- 
tance measurements.  If  the  material  has  the  required  prop- 
erties, it  is  shipped  to  the  fabrication  departnvent. 

Fobricof/'on  Technique 

Fabrication  of  the  glass  fabric  melaminc  resin  laminate 
is  done  with  metal  working  equipment  but  with  certain 
variations  to  fit  the  characteristics  of  the  material.  The 
matt-rial  is  clamped  and  supported  during  machining.  Where 
it  is  not  convenient  to  use  coolants,  it  is  necessary  that  good 
suction  be  provided  to  remove  chips  and  dust  or  otherwise 


Glass-Melamine  Laminate 

Effect  of  Aging  at  700  C  on  Flexural  Strength 


Aging  Tim 


Percentage  of  Original 
Strength  Retained 


Rote  of   heating   and   cooling   for  a  hall-Inch  thick   panel 


One  month 77 

Two  month! 71 

Three  months 56 

Four  months . .  42 


i'f,.t*rir.«. 


AUGUST  1916 


PLEXGL1S 


is  on  the  radio 


HThe  new  Emerson  radios  are  attracting  wide  atten- 
tion. Particularly  this  attractive  table  model  with  its 
grille  of  lustrous  PLEXIGLAS.  This  crystal-clear  plastic 
forms  a  shield  over  the  dial,  a  sparkling  grille  over  the 
speaker. . .  gives  added  distinction  to  a  beautiful  design. 


Grille  for  this  Emerson  Model  molded  by 
Plastimold  Inc.  and  Victory  Plastics. 


IfYour  own  products  can  be  similarly  enriched  by 
the  use  of  PLEXIGLAS.  Easily  fabricated  and  molded, 

PLEXIGLAS  lends  itself  readily  to  even  the  most  intricate  designs.  From  bottle  closures 
to  boudoir  furnishings,  the  unusual  properties  of  PLEXIGLAS  can  supply  just  the  extra 
eye-appeal  you  want. 

ITCall  or  write  our  nearest  office  for  information  or  technical  assistance:  Phila- 
delphia, Detroit,  Los  Angeles,  Chicago,  New  York.  Canadian  Distributor:  Hobbs 
Glass,  Ltd.,  London,  Ontario. 


Only  Rohm  &  Haas  makes 


PLEXIGLAS 


Acrylic  Plastic  Sheets  and  Molding  Poivders 


ROHM    &    HAAS    COMPANY 

WASHINGTON  SQUARE*  PHILADELPHIA,  PA. 

Manufacturers  ol  Cfiemicjli  including  Plastics  .  .  .  Synthetic  Insecticides         Fungicides  .  .    fniymcs  .  .  .  Chemi[3ls  f:r  the  Leather.  Te«Me  and  otter  Industries 


so 


f.c 


20 


X 


\ 


-7S       -SO        -»          O  25          50          75          100        125         ISC 


Izod  impact   »trenqth   is  influenced  by  fabric  treatment 

dermatitis  may  occur;  it  is  preferable,  however,  to  Use  :in 
air  blast  or  water  for  C(x>ling.  The  following  suggestions 
for  performing  some  fabrication  operations  are  submitted, 
since  they  have  become  standard  practice. 
DRILLIM::  Heavy  duty  drill  presses  should  be  used  run- 
ning at  speeds  of  500  rpm  to  1720  rpni.  depending  on  the 
thickness  of  the  laminate.  Tungsten-carbide  tip  drills  are 
recommended  with  an  included  angle  of  160-180°,  a  clear- 
ance angle  of  10°.  and  with  zero  or  slightly  negative  rake. 
A  .004"  per  revolution  feed  is  used  with  frequent  backing 
off  to  prevent  overheating. 

For  rectangular  shaped  holes  a  band  saw  is  used  with  a 
Yi"  12  pitch  blade  running  at  a  speed  of  60  fpm  for  thin 
materials  ami  50  fpm  for  heavier  stock.  The  material  is  cut 
at  a  rate  of  10"  per  tnin.  and  the  minimum  radius  that  can 
U-  cut  is  </;,". 

No  coolant  is  used,  but  it  desirable  that  good  suction  be 
used  to  remove  chips  and  dust. 


Properties   of   Melamine    Resin   Laminates    Made   with 
Various  Reinforcing  Agents 


Heat 

Lubri- 

Treated 

cated 

Clots 

Glass 

Asbestos 

Cotton 

Kraft 

Properties 

Fabric 

Fabric 

Fabric 

Fabric 

Paper 

Specific  gravity  .... 

2.0. 

20. 

18. 

]  4 

1  4 

Tensile  strength  (psi). 

35,000. 

.28,000. 

..12,000. 

..    8,000. 

..    8,000 

Flexural  strength  (psi. 

flatwise)  

48,000. 

.20,000. 

..21,000. 

..22,000. 

..19,000 

Compressive  strength 

(psi,  flatwise)  .... 

88,000. 

.80,000. 

..50,000. 

..50.000. 

..50,000 

Izod  impact  strength 

(ft-lb   in.) 

24 

32. 

6. 

3  _ 

1 

Bond  strength  (Ib 

1  ","  thickness!.  .  . 

1600. 

.       900. 

.  .     1  1  00  . 

..     1900. 

..     1000 

Water  absorption 

C  ,    on  24  hr  im- 

mersion at  25  C). 

1.3. 

1.0. 

1.2. 

1.0. 

3.5 

Arc  resistance  (sec)  .  . 

187. 

180. 

50. 

..       130. 

125 

Dielectric  strength 

(short  time,  v    m).  . 

400. 

.       350. 

100. 

..       400. 

..       500 

SAWINV.  AND  HKVEI.IX<;:  In  sawing,  water  as  a  coolant  is 
usually  recommended.  C'arlmrundum  or  metal-diamond 
wheels,  usually  16"  in  diameter,  are  used,  running  at  sjieeds 
of  1, SI  K  1-215(1  rpni  and  with  a  stock  feed  of  10-24"  per  niin. 
In  some  cases  a  wood  working  table  saw  is  used  having  a 
12-14"  diameter  carborundum-  resinoid  wheel  traveling  at  a 
speed  of  34<X)  rpm  with  a  stock  feed  of  10-40"  per  niin. 
SAXIMXI;:  Kinery  paper  of  24-40  fjrit  is  used  on  a  Yates 
American  ty|x-  machine  removing  .002  to  .005"  per  pass. 
No  coolant  is  used,  but  the  dust  is  removed  by  suction. 
M  AI  MINIM;  (  Turning)  :  For  turning,  the  standard  type  of 
machine  can  IK-  used  with  a  tungsten-carbide  tip  lathe  tool 
having1  a  33°  clearance  and  10°  negative  rake.  Peripheral 
speeds  of  150-300  fpm  and  feeds  of  .002- .003"  per  revolution 
are  employed.  No  coolant  is  used,  but  chips  and  dust  are 
removed  by  vacuum. 

Characteristics  of  the  Laminate 

Melamine  glass  fabric  laminate  is  made  from  two  basic- 
ally brittle  and  relatively  weak  materials,  yet  the  laminate 
is  tough  and  very  strong.  The  explanation  lies  in  the  use 
of  glass  in  the  form  of  very  fine  filaments.  Kach  filament 
has  a  minimum  tensile  strength  of  200,000  psi.  While  the 
filaments  in  themselves  are  quite  brittle,  the  use  of  bundles 
of  filaments  cemented  together  with  resin  gives  the  compos- 
ite material  great  impact  strength.  This  tieing  together  of 


Comparative  Properties  of  Laminated  Plastics  and  Structural  Metals 


Material 

Specific 
Gravity               Weight 
(Ib  cu  ft) 

Tensile 

Strength 
(pit) 

Yield 

Strength 
(pill 

Modulus  of 
Elasticity 
<P*I> 

Specific* 
Tensile 

Strength 

Od) 

Specific* 
Yield 
Strength 

(psi) 

Lubricated  gloss  fabrk  melamine  resin  laminate  .  .  2.0    
Meat  treated  glass  fabric  melamine  2.0    

Dowmetal  H  (heat  treated)  1  .83  
Dowmetal  H  (heat  treated  and  aged)  1  .83  
Aluminum-copper  alloy  No.  12  (SAE  30)  2.83  
Aluminum-copper  alloy  (SAE  38)  heat  treated  ....  2.77  
Gray  cast  iron  (Class  40,  ASTM  A48-35T)  7.2    
Cast  steel  10.30'  ,   C  annealed)  7.86  

Dowmetal  J  (extruded)  1.80  
Dowmetal  X  (eitruded  and  aged)  1.80  
Duralumin  2.79  
Structural  steel  7.85  
Chromium-molybdenum  steel  7.85  

laminated  Plastics 
.124  28,000  
.124  35,000  
Cast  MetaU 
.113  38,000  
.113  38,000  
.178  22,000  
.174  36,000  
.450  40.000  
.490  76.000  

..24,000  
..31,500  

..12,000  
..19,000  
..14,000  
..22,000  

.    2,600,000.  .. 
3,300,000... 

6,500,000... 
.    6,500,000... 
.10,000,000... 
.10,000,000... 
.18,000,000.  .. 
29,000,000... 

6.500,000  
.    6,500,000... 
.10,000.000... 
.29.000,000.  .. 
29.000.000... 

....14.000  
....17,500  

....20,800  
20,800  
.  ...    7,800  
....13,000  
.  ...    5,600  
....    9^00  

23,900  
....24,400  
21,500  
.  ...    7,600  
....15.900  

.12,000 
.  1  5.700 

.    6.600 
.    9,800 
.    5,000 
.    7,900 

..42.000  

..30.000  
..34,000  
..36,000  
..36,000  
..90,000  

.    5,300 

.  1  6,700 
.  1  8,900 
.  1  2,900 
.    4.600 
.11,500 

.112  
.112  
.174  
.490  
.490  

43,000  
44,000  
60,000  
60,000  
125,000  

•TK»  teecMc  fenifle  •*•«•*.  owd  i»«<Jnc  yl 

68 

eW  OrwiaHi.  or*  »q»ol  to  MM  1 

'•mi\*  itrenam,  ond   yt«ldJ»H»ngtt>.  r*ip«<t)v»ty.  in  p 

PLASTtCS 

..  d...d.d  by  !•>•  ipecMc  grevHy. 

AUGUST 

1946 

fine  filaments  also  results  in  high  flexural  and  compressive 
strengths. 

In  analyzing  the  tensile  strength  of  glass  yarn,  glass 
fabric  and  glass  laminate  to  determine  if  these  materials 
possess  the  maximum  strength  possible  on  the  basis  of  the 
amount  and  strength  of  glass  filament  present,  we  find  that 
we  do  not  realize  all  the  strength  available. 

These  lower  strengths  are  due  to  the  large  number  of  dis- 
continuities present  because  of  the  larger  total  length  of 
filaments  in  these  materials  as  compared  to  the  length  of  a 
single  filament,  which  will  contain  a  minimum  amount  of 
weak  spots.*  Another  factor  contributing  to  lower  strength 
values  is  the  premature  failure  of  weak  filaments,  thus  de- 
creasing the  effective  number  in  the  bundle  and  putting  a 
greater  stress  on  those  remaining.  In  the  laminate,  the 
resin  fails  first.  This  tends  to  put  an  impact  concentration 
of  force  on  the  filaments— an  action  which,  combined  with 
gradual  failure  of  individual  filaments,  results  in  a  lower 
ultimate  strength. 

As  mentioned  previously,  the  lubricant  used  on  the  glass 
fabric  has  an  influence  on  the  efficiency  of  the  resin  bonding. 
This  is  clearly  brought  out  on  examining  the  properties  of 
laminates  made  from  the  lubricated  fabric  and  from  the  heat 
treated  fabric.  The  best  treated  Fiberglas  laminate  has 
higher  bond,  tensile,  flexural  and  compressive  strengths 
but  a  lower  impact  strength  than  the  lubricated  Fiberglas 
laminate.  The  heat  treated  Fiberglas  laminate  has  the 
higher  modulus  of  elasticity  and  yield  strength. 

It  is  interesting  to  compare  the  strength  properties  of 
glass  fabric  melamine  resin  laminates  and  structural  metals. 
Unlike  steel  but  similar  to  aluminum  alloys  and  magnesium 
alloys,  plastics  laminates  do  not  exhibit  sharp  yield  points 
when  subjected  to  the  usual  tensile  tests.  Instead  they  break 
away  gradually  from  the  modulus  line.  The  yield  strength 


I 

ft  10000 


V 


0  20  4O  60  80  100 

TIME  M  HOUKS  AT  95%  H£LATIVE  HUMIDITY  AHD  SO'C 


Humidity   effects   on   insulation   resistance   of   laminates 


TAPS  ALL- 
PLASTICS 

Cuts  deep,  smooth, 
clean  threads  with- 
out chipping  holes. 


HOLTXTE 


SCREW 


Other 


Furnished 
with  Slotted 
or  HOLT  IT  E- 
Phillips  Recessed 
Heads-All  Styles 


Pilot  point  in- 
serted in  hole 
aligns  screw 
for  straight 
driving 


V>^    vjjo       a^     i 

>  \^  ,\&eS  ^  e^e.     c^)J.  " 

^P^% 


A  practical,  production-proved  hardened  screw  that 
actually  taps  its  own  perfect  mating  threads  in  any  ma* 
terial!  In  plastics  it  cuts  deep,  smooth  threads  without  chip* 
ping  material  around  edges  of  hole,  or  bulging  hole  per* 
imeter  upwards  in  laminated  plastics  with  paper  or  cloth 
fillers.  Length  of  thread  that  can  be  tapped  by  this  remark- 
able screw  is  many  times  greater  than  its  own  diameter. 

Open  slot  ship  reservoir  readily  frees  tough,  gummy,  non- 
metallic  cuttings  to  prevent  binding  and  reduce  driving 
torque  and  effort.  Send  for  samples  and  descriptive  folder. 


CONTINENTAL 

SCREW  COMPANY 

New  Bedford,  Massachusetts.U.S.A 


AUGUST  1946 


PLASTiCS 


MANUFACTURERS    OF 


CELLULOSE  ACETATE 
MOLDING  POWDERS 
ANY  COLOR  ANY  FLOW 


Comparison  of  Phenolic  vs  Melamine  Glass  Laminates 


Tensile  strength  (psi) 28,000 28,000 

Flexurol  strength  (psi,  flatwise) 1  6,000 20,000 

Compressive  strength  (psi,  flatwise) 50,000 80,000 

zod  impact  strength  (ft-lb   in.  width, 

flatwise) 20 32 

Bond  strength  (Ib    •  2 "  thickness) 100 900 

Arc  resistance  (sec) 5 1  80 


for  such  material  i-.  u>u:tlly  defined  as  the  point  where  the 
stress-strain  curve  deviates  0.2%  from  the  modulus  line. 

An  accompanying  table  shows  the  comparative  proper  tii  ~ 
of  laminated  plastics  and  structural  metals.  The  laminate-. 
have  a  low  specific  gravity,  only  slightly  higher  than  mag- 
nesium alloys,  the  lightest  metals  in  the  li>t.  Like  magne- 
sium alloys,  then,  the  use  of  pla>tics  would  mean  .Caving  in 
weight  for  equal  volumes.  The  tensile  strength  of  the  lami- 
nates is  greater  than  aluminum-copper  alloys  but  less  than 
for  the  other  metals.  However,  the  specific  tensile  strength, 
especially  of  the  heat  treated  fabric  laminate,  is  higher 
than  that  of  any  of  the  cast  metals  except  the  magne>iiiin 
alloys ;  in  the  case  of  the  wrought  metals,  the  laminate  has 
a  higher  specific  tensile  strength  than  structural  steel  or 
chromium- molybdenum  steel  but  lower  than  that  of  the 
magnesium  alloys  and  duraluminum.  The  yield  strength  of 
the  laminated  plastics  is  fairly  high,  being  greater  than  that 
of  all  of  the  cast  metals  except  cast  steel.  All  of  the  wrought 
metals  except  Dowmctal  J  have  higher  yield  strengths  than 
the  plastics.  If,  however,  the  specific  yield  -trengths  are 
compared,  we  find  that  the  laminated  plastics,  especially  the 
heat  treated  type,  ranks  high.  Only  the  wrought  niagne-uiui 
alloys  have  a  higher  specific  yield  strength  than  the  pla>tic> 
which  are  heat  treated. 

(Continued  on  page  80) 


•  F.  O.  Anderecf.  1*4.  fr  Eng.  Cktm.,  March  19J9.  pp.  290-29S— effect 
of  discontinuities  on  strength. 


~T  t  345»»t«»  10         BO    40    S0*0»» 

DAft  IHH*»»»t>  I*  M*rt*  AT   fO'C 

A  comparison  of  water  absorption  ol  the  following  type" 
of  laminates:  (1)  krail  paper-phenolic  retin:  (2)  cotton 
fabric-phenolic  resin:  (3)  qlau  fabric  melamtne  resin; 
(4)  asbestos  fabric  phenolic  resin:  and  (5)  qlass  fabric- 
phenolic  resin.  Specimens  tested  were  1"  X  1"  •  '7"  thick 


70 


AUGUST  1946 


Splints  Utilize  Plastics 

Aiding  in  correction  of  muscular  weakness  and  contracture,  new 
, supporting  device  is  sturdy,  lightweight,  comfortable  to  wear 


y 


W.  <£.  St-L 


<.en 


AXKW  application,  in  the  making  of  splints,  has  been 
developed  for  plastics,  which  have  already  found 
many  uses  in  prosthetic  units.  Special  progress  in  this 
development  has  been  made  at  the  U.  S.  Naval  Hospital, 
St.  Albans,  N.  Y.,  originating  in  the  occupational  therapy 
department.  Other  Navy  hospitals  also  have  been  success- 
fully experimenting  with  the  plastics  splint,  among  them 
the  Philadelphia  Naval  Hospital. 

Generally  speaking,  a  splint,  in  most  of  its  applications, 
is  a  containing,  supporting  or  positioning  device.  The 
familiar  splint  for  a  fracture  is  an  example,  but  there  are 
also  splints  for  disabilities  other  than  fractures — for  in- 
stance, those  which  support  joint  weakness  or  oppose  joint 
contracture.  These  have  hitherto  been  made  of  metal, 
usually  steel  or  aluminum,  or  of  plywood,  frequently  with 
leather  utilized  as  an  accessory. 

Although  the  range  of  application  of  the  plastics  splint  is 
still  in  the  process  of  expansion,  two  observations  may  be 
made  about  it  at  this  time.  One  is  that  it  probably  cannot 
forseeably  replace  metal  for  movable  (especially  swiveling) 
components ;  the  other  is  that  there  seems  no  reason  to 
doubt  that  plastics  can  replace  metal  and  plywood  in  fixed 
splints  or  components,  in  a  great  proportion  of  instances. 

Judging  by  observation  at  St.  Albans,  from  the  viewpoint 
of  the  patient,  the  plastics  splint  has  proved  itself  superior 
to  the  other  materials  in  a  number  of  respects.  It  is  lighter 
than  metal,  more  comfortable,  more  pleasant  in  contact  with 
the  skin.  And  a  factor  of  great  psychological  importance 
is  that  it  has  far  less  of  the  appearance  and  cannotation  of 
a  mechanical  device  alien  to  the  body,  since  most  of  the 
plastics  splints  are  of  transparent  methyl  methacrylate 
through  which  the  limb  can  be  seen. 

Actually,  the  idea  of  the  plastics  splint  originated  with 
the  St.  Albans  hospital  patients  themselves.  Lt.  Harriet  J. 
Tiebel,  occupational  therapy  officer,  relates  that  a  patient 
who  had  been  working  on  plastics  in  the  workshop  of  the 
department  came  to  her  with  the  suggestion  that  a  plastics 
splint  be  made  for  his  own  disability,  to  replace  the  old 
splint,  which  was  made  of  metal.  Lt.  Tiebel,  considering 
this  a  worthwhile  experiment,  obtained  the  necessary  medi- 
cal approval  to  proceed  with  it.  The  patient  who  had  made 
the  suggestion  constructed  the  first  splint  of  Plexiglas;  it 
fulfilled  its  function  perfectly,  the  patient  was  delighted 
with  it,  and  other  patients  asked  for  plastics  splints,  many 
of  which  are  now  made  on  requests  originating  with  the 
hospital's  physicians.  In  all  cases,  the  specifications  are  set 
by  the  patient's  doctor,  who  also  approves  the  fitting  and 
the  final  product. 

Two  Genera/  Types 

The  splints  selected  as  examples  in  this  discussion  are 
for  disabilities  which  fall  into  two  general  categories — 
muscular  weakness  and  muscular  contracture.  The  weak- 
ness or  contracture  generally  involve  a  joint  or  joints,  and 
may  be  primary  (that  is,  integrally  involved  with  an  injury) 
or  it  may  be  secondary  (following  and  associated  with  in- 
jury). The  function  of  a  splint  applied  to  a  weakness  is 
to  support  the  member — hand,  finger,  leg,  foot,  etc.;  the 


Methyl  methacrylate  provides  strong  support  in  "wrist 
drop"   condition,   while   permitting   freedom  of   fingers 

For  a  "palm  splint,"  patient's  hand  is  pressed  into 
dental   compound   to   form   pattern   for  a   split   mold 


AUGUST  1946 


71 


Tendency  of  affected  lingers  to  curl  inward  is  checked 
by    means    of    light    but    firm    linger-contracture    splint 


Ingeniously    designed   unit   counteracts    loss   of    use    of 
opponens  muscle  of  thumb  by  immobilizing  flexor  muscles 


function  of  the  splint  used  for  contracture  is  to  oppose  that 
contracture. 

An  example  of  weakness  is  found  in  a  condition  described 
as  "wrist  drop,"  in  which  the  wrist  is  relaxed  and  the 
patient  finds  it  impossible  to  bring  his  hand  up  to  normal 
position  or  to  maintain  it  in  such  position.  The  condition 
is  temporary  and  is  corrected  eventually,  but  the  joint  needs 
immediate  support  in  an  approximately  normal  position, 
especially  since  a  continuation  of  the  relaxed  state  will 
lengthen  the  recovery  period.  The  necessary  support  is 
provided  by  a  splint. 

Splints  designed  for  contractural  disabilities  are  devised 
to  prevent  the  affected  members  from  "drawing  in"  or  con- 
tracting, by  opposing  their  tendency  to  do  so. 

The  occupational  therapy  division  of  the  St.  Allans  hos- 
pital is  at  present  using  two  methods  for  producing  plastics 
splints — fabrication  and  casting. 

In  forming  various  splints  of  plastics,  I'lexiglas  sheet 
stock  from  -Tie"  to  %i"  is  used.  To  make  a  supporting  splint 
for  the  "wrist  drop"  condition,  employing  conventional 
forming  and  maching  processes,  the  patient's  hand  is  placed 
on  the  masking  paper  which  initially  covers  the  acrylic 
sheet,  the  fingers  are  straightened  to  normal  position,  and 
an  outline  of  the  hand,  wrist  and  a  few  inches  of  forearm 
is  traced  on  the  marking  paper.  The  sheet  is  then  jig- 
sawed  to  outline  and  the  paper  is  stripped  off.  All  edges 
and  corners  are  ground  t»  a  bevel  or  a  radius  and  are 
sanded  and  buffed.  The  work  is  then  softened  in  boiling 
water  and  is  formed,  at  the  wrist  location,  to  the  angle 
required  for  projier  support.  Air  holes  arc  drilled  to  pro- 
vide  ventilation,  and  hole-,  are  drilled  and  tapped  to  anchor 
the  leather  straps,  which  arc  then  attached,  making  the 
splint  ready  for  use.  The  same  technique  is  employed  to 
fashion  similar  splints  for  other  condition 

isionally  the  splint  may  have  a  complex  contour, 
involving  a  fairly  complex  forming  problem,  such  as  hav- 
ing to  be  shaped  around  a  thumb  or  finger.  Obviously,  the 
hot  methacrylatc  sheet  cannot  be  formed  on  the  patient's 


hand,  and  since  inter|K>sition  of  sufficient  heat-insulation 
would  throw  off  dimensions,  other  means  must  be  adopted 
for  the  work.  A  plaster  of  Paris  pattern  of  the  hand  would 
seem  to  be  the  logical  procedure.  It  has  been  found,  how- 
ever, that  a  more  indirect  method  afforded  greater  flexi- 
bility of  process.  The  patient's  hand  is  placed  in  the  posi- 
tion in  which  it  is  to  be  held  by  the  splint,  and  dimensions 
are  taken.  The  1'lexiglas  sheet  is  cut  to  approximate  out- 
line, heated,  and  then  hand-formed  to  dimensions.  In  the 
instance  observed,  the  finished  splint  fitted  perfectly.  If  it 
had  not,  however,  it  would  have  l>een  heat-softened  again 
and  adjusted  to  correct  any  misalignments  apparent  in  the 
first  fitting. 

Casting  procedure  is  used  where  contours  of  the  affected 
member  are  to  be  followed  accurately  or  where  forming 
may  not  IK-  practicable  for  one  reason  or  another. 

In  this  process,  the  patient's  hand  is  greased  and  is 
pressed  down  into  warm  dental  compound,  a  low  melting 
point  material  composed  of  French  clay,  wax  and  coloring 
matter.  The  impression  "sets"  immediately  upon  immer- 
sion in  cold  water.  ProtuU-ranccs  and  rough  surfaces  are 
sanded  off  this  cast,  which  is  then  taken  to  the  hospital'. 
dental  laboratory.  Here  the  east  s,.rves  as  the  pattern  for 
a  split  mold  made  of  dental  stone.  In  its  unprocessed  form 
dental  stone  is.  essentially,  powdered  gypsum,  pigmcnted. 
which,  when  mixed  with  water,  ultimately  sets  to  hard- 
ness. Handling  of  the  material  is  fairly  critical,  since  it 
must  be  worked  during  the  peri<xl  of  setting,  an  interval, 
usually,  of  only  about  10  min  for  the  medium-consistency 
mix  Used  for  this  work. 

For  the  casting  itself,  dental  acrylic  is  used  in  the  ratio 
of  one  part  monomer  to  two  powder  by  volume,  a  mix 
fairly  similar  to  that  required  for  dentures.  In  about  10 
min.  the  compound  sets  to  a  point  of  viscosity  where  it  is 
iMitli  kneaclahle  ami  stretcliahlc.  It  is  then  laid  on  in  the 
mold  and  the  mold  is  closed. 

i  ure  takes  the  following  sequence:  The  mold  is  im- 
mersed in  water  which  is  brought  up  to  150°  F  ami  main- 


72 


PM.AST1CS 


Al  <il  ST     194fi 


taincd  at  that  temperature  for  approximately  30  mm,  when 
it  is  raised  to  boiling  point.  After  an  hour  of  this  treatment, 
the  mold  is  permitted  to  cool  at  room  temperature  for  1 
15  min     It  is  then  immersed  in  hot  water,  the  temperature 
of  which  is  gradually  reduced  by  a  rill  of  cold  water, 
acrvlic  casting  in  the  mold  is  thus  set,  gradually.     A  few 
finishing  operations  in  the  occupational  therapy  workshop 
and  affixing  of  the  straps  complete  the  splint. 

The  possibilities  of  plastics,  especially  of  methyl  metna- 
crylate,  in  splint-making  have  probably  hardly  been 
plumbed  by  the  pioneering  at  St.  Albans  hospital.  For 
instance,  the  use  of  plastics  for  fixed  components  in  com- 
bination with  metal  for  swivel- joints  and  other  movable 
parts,  is  only  just  about  to  be  explored.  In  any  case,  judg- 
ing from  the  results  obtained  at  St.  Albans,  there  is  every 
reason  to  expect  the  development  to  gain  a  place  in  civilian 
therapy,  as  well. 


Container  Fabrication 

(Continued  from  page  48) 


of  1 :2  at  the  rate  of  90  to  100  pieces  a  minute.  This  com- 
pares with  a  maximum  production  rate  of  18  pieces  per 
minute  by  the  best  semi-automatic  drawing  machines. 

This  comparison  does  not,  however,  reveal  the  actual 
labor  cost  differential.  Since  a  single  unskilled  operator 
can  attend  a  battery  of  six  automatics,  he  produces  at  a 
rate  at  least  20  times  as  great  as  the  skilled  operator  at  a 
semi-automatic.  The  disparity  becomes  even  greater  com- 
pared with  the  production  of  a  wholly  manually  operated 
machine. 

While  this  discussion  has  been  confined  to  the  methods  of 
fabrication  and  the  automatic  machinery  needs  of  containers 
made  entirely  of  rigid  sheeting,  the  considerations  apply,  as 
well,  to  containers  that  combine  this  material  with  metals, 
wood  or  paper-board.  In  some  cases,  the  chief  difference 
is  in  the  method  of  attachment  of  one  material  to  the  other, 
as  of  a  metal  bottom  to  a  plastics  container.  This  is  usually 
spun  or  crimped  on.  On  the  other  hand,  the  paper-bottomed 
container  requires  the  same  method  of  attachment  (cement- 
ing) as  the  all-plastics  box.  As  for  bead-seated  bottoms, 
there  is  rarely  any  difference.  END 

NOTE:  This  is  the  last  in  a  series  of  three  articles  on  container  fabrica- 
tion. 


Know  Your  Acetates 

(Continued  from  page  32) 


eventually  the  lower  wave  lengths  produce  a  surface  degra- 
dation, this  action  is  very  slow  and  may  be  retarded  by 
suitable  agents.  Acetate  has  had  a  long  record  of  success 
as  a  medium  for  transmitting  ultraviolet  rays  into  solaria 
and  hen  houses.  More  recently  it  has  been  used  to  make 
wire-reinforced  windows  which  are  exposed  to  bomb  blasts. 

Of  special  importance  in  hot-molded  plastics  is  the  prop- 
erty of  resisting  degradation  at  high  temperatures,  and 
acetates  possess  this  property  to  a  marked  degree. 

Cellulose  acetate  articles  are  unaffected  by  weak  organic 
acids;  mineral,  animal,  and  vegetable  oils;  and  gasoline. 
The  high  acetyl  types  are  particularly  resistant  to  organic 
solvents;  in  general,  cellulose  acetate  is  highly  solvent- 
resistant.  This  property  leads  to  many  end  uses  in  pack- 
aging. 

Because  acetate  has  high  internal  and  surface  resistance 
to  the  flow  of  electric  current,  it  is  also  used  as  an  insulating 
coating  for  wires  and  coils.  Furthermore,  it  combines 
generally  good  insulating  properties  with  good  corrosion 


Ingenious  New 

Technical  Methods 

To  Help  You  with  Your 
Reconversion  Problems 


Interchangeable  Dynamometer 


Portable  Tester  Checks  Tensions  Up  To 
10,000  Ibs.- Right  at  the  Workbench! 

Standing  only  37"  high,  weigh- 
ing but  137  Ibs.,  the  Dillon  Uni- 
versal Tester  checks  wire,  cop- 
per, aluminum,  fabrics,  steel,  etc. 
for  tensile,  transverse,  compres- 
sion and  shear  strengths.  Avail- 
able in  7  capacities,  with  inter- 
changeable dynamometers,  the 
Universal  will  test  from  0  to 
10,000  Ibs.  Special  gripping  jaws 
are  made  for  every  requirement. 

The  Universal  Tester  may  be  either 
hand  or  motor  operated.  No  spe- 
cial training  is  needed  to  record 
accurate  results  instantly  on  the 
dynamometer.  It  is  compact, 
simple,  inexpensive  —  designed 
for  small  shops  and  plants  every- 
where. 

Tests  prove  that  workers,  too, 
undergo  strain  and  nervous  ten- 
sion on  the  job.  That's  why  many 
factories  urge  workers  to  chew 
gum.  Workers  can  chew  Wrigley's 
Spearmint  Gum  right  on  the  job 
— even  when  hands  are  busy.  And 
the  act  of  chewing  helps  relieve 
monotony— helps  keep  workers 
alert,  thus  aiding  them  to  do  a 
better  job  with  greater  ease  and 
safety. 

You  can  get  complete  information  from 
W.  C.  Dillon  &  Company,  Inc. 
W.  Harrison  St.,  Chicago  44,  111. 

AA-79 


AUGUST  1946 


PLASTICS 


73 


TO  YOUR  SPECIFICATIONS 

For  over  forty  years  we  have  been  leaders  in  the  design 
and  manufacture  of  component  parts  for  leading 
Refrigerator,  Stove,  Furniture,  Appliance  and  Cabinet 
industries.  We  specialize  in  custom  molding  by  the 
injection,  compression  or  transfer  method  in  any  ther- 
mosetling  or  thermoplastic  material.  A  complete  ser- 
vice from  one  source  to  serve  your  needs  —  at  no 
extra  cost. 


RESEARCH  — 

Highly  experienc- 
ed research  engi- 
neers to  deter- 
mine the  material  best  tutted 
for  your  needs  as  to  strength, 
utility  and  beauty. 


ENGINEERING— 
Here  is  where  the 
correct  tools,  pre- 
cision dies  and 
molds  are  developed  to  pro- 
duce the  best  job,  efficiently 
and  economically. 

j>  9         MOLDING    —   A 

JL3BH    complete    depart- 

I   meot  equipped 

with    the    latest 

and  most  modern  presses  and 

molding    equipment    —    for 

Injection,     Compression     or 

Transfer  molding. 


DESIGN  —  A  thor- 
ough study  is  made 
as  to  the  utility, 
shape  and  color  of 
the  plastic  part  that  will  best 
harmonize  with  the  style  and 
design  of  your  product. 


TOOL  AND  MOLD 
MAKING    —   This 

department,  manned 
by  expert  crafts- 
men, makes  the  necessary 
tools  and  molds  to  produce 
the  finished  product. 


INSPECTION 
AND  SHIPPING 

Each  individual 
piece  is  carefully 
inspected  for  uniformity,  col- 
or and  finish.  All  pans  aw 
carefully  wrapped  ana  packed 
for  utmost  protection. 


//  you  tat  pltmtimg  tkt  tut  of  flattie  parli  in  your 
pTodudi,  it  uilt  be  aJi'imlageoui  for  you  lo  iititili- 
gflt  our  compltle  trnict.  Writ*  or  phone  HI  about 
your  nttdi. 


IN! 

x« « *w 


NATIONAL    LOCK 
COMPANY 

Plastics    Division 

ROCKFORD.    ILLINOIS 


and  arc  resistance — a  valuable  combination  for  use  in 
electrical  apparatus.  Although  vinyls  are  also  used  to  a 
considerable  extent,  they  cannot,  by  and  large,  be  used  in 
the  insides  of  motors  because  of  their  low  softening  point. 
whereas  acetate-  can.  In  addition,  acetate  foil  can  be  made 
thinner  and  with  a  higher  dielectric  strength  than  vinyls. 

Cellulose  acetate  is  used  as  a  safety  photographic  film  to 
replace  the  more  combustible  nitrate,  for  it  is  very  slow 
burning  and  generally  is  no  more  of  a  fire  hazard  than 
wood  or  paper.  By  incorporating  flame-retarding  pla-tici/- 
ers  into  the  molding  compounds,  flame  resistance  can  be 
further  increa-ed. 

The  general  workability  of  cellulose  acetate  should  not 
be  overlooked.  It  is  easily  machined,  punched,  stamped, 
sheared,  sawed,  drilled,  embossed,  and  cemented — important 
factors  in  the  fabrication  and  assembly  of  plastics.  In 
addition,  although  it  can  be  readily  molded  with  a  beautiful, 
lustrous  finish  through  the  use  of  polished  molds,  it  can 
be  buffed  and  polished,  after  machining,  to  get  a  smooth 
surface.  The  ease  of  molding  of  this  material  is  shown  in 
the  fact  that  it  lends  itself  to  the  practice  of  using  metal  «r 
wooden  cores  and  inserts  in  the  mold  cavities.  Hot-forming, 
or  stamping  small  pieces  from  cellulose  acetate  sheet-,  i- 
another  widely-used  procc--.  i  \u 


Textiles  on  the  Wall 

(Continued  from  page  41) 


Wallfab  is  bendable,  fitting  easily  into  and  around  cor- 
ners even  though  its  thickness  of  .020"  is  twice  that  of 
average  wallpaper.  It  is  easily  hung  in  place,  although 
brief  instruction  in  hanging  is  advisable,  inasmuch  as  the 
ordinary  wallpaper  paste  or  other  adhesive  should  be 
allowed  to  "set"  for  15  to  20  minutes  after  application,  due 
to  the  fact  that  the  paste-smeared  laminate  tends  to  expand 
slightly  at  first.  Any  residue  of  adhesive  on  the  outer  sur- 
face can  be  washed  away. 

Accelerated  laboratory  aging  tests  on  the  product  have 
indicated  no  cracking  or  peeling  tendencies,  according  to 
the  manufacturer. 

Due  to  hand  "lay-up"  combined  with  current  high  cost 
of  ingredients  the  retail  price  of  ll'allfab  is  at  present  at 
least  twice  as  high  as  that  of  other  wall  coverings;  it  aver- 
ages approximately  35c  per  sq  ft  for  most  custom  and  com- 
mercial fabrics — or  a  textile  which  has  been  selected  and 
purchased  by  the  consumer  can  be  treated  for  J5c  per  sq  ft 
Its  cost  is  no  factor  in  its  use  where  wall-covering  damage 
is  usually  most  frequent — such  as  in  children's  rooms, 
breakfa-t  nooks,  kitchen-,  etc.  Industrially,  it  i-  recom- 
mended for  public  eating  and  drinking  establishments, 
lounges,  elevator  interiors,  and  wherever  walls  are  likely  to 
receive  strenuous  treatment. 

A  major  aircraft  company  is  currently  testing  the  prod- 
uct for  use  in  transport  interiors.  Possibilities  in  this  liiv 
include  sheathing  of  and  by  varying  the  impregnation 
process  to  supply  a  rigid  rather  than  a  flexible  construction, 
for  erection  of  compartment  partitions.  Aircraft  executives 
have  expressed  interest  in  the  color  potentialities  of  these 
fabrics  in  place  of  veneers  and  paints,  as  well  as  in  their 
\\a-hability,  durability  and  lightness  of  weight. 

As  a  sideline  to  its  wall-covering  manufacture,  the  com- 
pany produces  table  mats — both  flexible  and  rigid — em- 
ploying s|x-cial  designs;  mats  are  "laid-up"  without  paper 
backing.  Other  n-es  for  this  decorative  laminate  include 
those  of  lamp  shades,  table  tops  and  colorful  \\a-ti-li.. 
The  firm  is  likewise  studying  the  marketing  possibilit 

such  as  book  covers,  automobile  interior  covering. 
and  certain  laboratory  bench  coverings. 


71 


FI..ISTI t  •* 


AUGUST  IHIfi 


Fabrics  coated  (in  transparent  or  opaque  colors)  by  "Geon" 
latex    process    are    washable,    durable,    and    scuff-resistant 

Versatile  Vinyls 

Find  a  New  Application 


vO          .  oL. 


Chemical   Engineer 
B.   F.   Goodrich   Chemical   Co. 


THE  USE  of  polyvinyl  resins  has  achieved  new  outlets 
with  the  recent  development  of  a  water-dispersed  vinyl 
chloride  type  polymer  known  as  Geon  latex.  All  of  the  fa- 
vorable characteristics  of  the  polyvinyl  resins  can  be  ob- 
tained by  processing  with  this  latex,  and  the  nature  of  the 
material  adapts  it  particularly  well  to  protective  coatings, 
as  an  addition  to,  and  a  partial  replacement  for,  solvent  type 
coatings. 

To  date,  major  applications  of  Geon  latex  have  been  in 
proofing  (coating)  fabrics,  particularly  those  designed  for 
military  end-use  (such  as  spread-coated  paulins  and  sail 
cloth),  and  dip-coated  rayon,  nylon,  and  other  lightweight 
fabrics.  These  coated  fabrics  have  met  abrasion  resistance, 
waterproofness,  and  flameproofness  specifications.  Because 
of  actual  penetration  of  the  resin  into  the  fibers,  latex  meth- 
ods result  in  coatings  which  have  an  excellent  adhesion  to 
fabrics. 

Other  qualities  of  the  new  latex-coated  fabrics  and  threads 
which  suggest  widespread  applications  are  good  wear  and 
scuff  resistance;  availability  in  a  wide  color  range  and  in 
finishes  from  dull  to  glossy  and  transparent  to  opaque;  re- 


New  method  of  applying:  coatings 
is  easy  to  use,  economical,  free 
of  flammable  and  toxic  solvents 


sistance  to  grease ;  washability ;  printability ;  resistance  to 
shrinking;  and  good  electrical  properties. 

Among  present  or  possible  application  for  these  fabrics 
are  lightweight  raincoats,  shower  curtains,  umbrellas,  and 
similar  items;  tents,  awnings,  and  like  materials;  and  so  on. 
Threads  and  yarns  can  be  impregnated  and  coated  to  pro- 
duce a  variety  of  properties,  including  water,  oil,  and  abra- 
sion resistance,  which  would  make  them  particularly  adapt- 
able, in  the  heavier  grades,  for  use  in  stitching  leather, 
heavy  canvas,  and  similar  materials;  and  for  use  as  win- 
dow screens  or  automobile  seat  covers,  where  breathing 
qualities  are  required  plus  washability  and  grease  and  abra- 
sion resistance. 

In  conjunction  with  paper,  the  use  of  the  latex  as  a  bond- 
ing agent  in  paper  pulp  to  obtain  papers  of  high  wet  strength 
is  a  distinct  possibility,  as  is  the  manufacture  of  improved 
paper  packaging  items  and  washable  wall  paper. 

Good  electrical  properties,  plus  abrasion  resistance  and 
flameproofness,  have  resulted  in  development  of  thin  wall 


AUGUST  1946 


VLASTtCS 


75 


Accurate   concentricity    of    thin    wall    Insulation    is   given 
by  latex  process.    Colors  can  be  used  to  identify   wires 


inflation  of  wire  by  latex  processing,  which  gives  an  ac- 
curate concentricity  of  coatings  for  thin  wall  insulation  dif- 
ficult to  obtain  by  other  methods.  Furthermore,  the  variety 
of  colors  obtainable  makes  possible  ready  identification  of 
wires  for  radio  hook-ups  and  communication  systems. 

Beautiful  leather  finishes  in  colors  can  be  obtained  on 
cheap  grades  of  leather  by  latex  methods.  A  spread  or 
spray  coating  of  leather  followed  by  press  polishing  gives  an 
attractive  material  for  leather  products.  Grain  leather  can 
be  lightly  coated  to  increase  its  water,  grease,  and  scuff 
resistance  and  then  embossed  to  improve  its  appearance. 
Possible  uses  are  in  shoe  uppers,  hand  bags,  and  luggage. 

In  many  operations  and  applications,  simplicity  of  pro- 
cedure plus  economic  factors  will  designate  the  choice  of  a 


FABRIC  DIE 
SMOOTHS  COATIMO 
AND  REMOVES'.XCESS 


GEON  PLASTICS    LATEX 
COATIN3  BATH 


In  experimental  coating  apparatus,  the  bath  pulley  will 
vary  In  site  according  to  the  type  and  thickness  ol  the 
end  product.  Tower  diameter  is  approximately  3".  length 
ir.  Speed  Is  10-50  fpm.  depending  on  coating  thickness 


latex  process.     In  some  cases,  this  method  will  serve  when 
other  resin  methods  are  unsatisfactory. 

The  advantages  of  the  Geon  latex  process  over  the  solvenl 
process  are  many.  The  dispersion  of  the  polyvinyl  resin  ir 
water  eliminates  the  use  of  an  expensive  solvent  and  thus 
the  need  for  a  cumbersome  solvent  recovery  system,  dangei 
from  inflammable  solvents  is  avoided,  and  there  are  n 
fumes  resulting  from  the  use  of  water. 

Finally,  as  seen  in  the  table  of  properties  of  these  latices 
the  percentage  of  solids  ranges  from  54-58rt.  This  con* 
pares  with  an  approximate  20%  solids  content  of  solvenl 
solutions.  Accordingly,  the  latices  will  give  a  coverage  twc 
to  three  times  heavier  than  a  solvent  solution,  which  cat 
mean  the  elimination  of  one  or  more  passes  through  the 
coating  machine. 

Water  has  one  disadvantage  in  that  it  causes  .shrinkage 
of  certain  fabrics.  This  can  be  avoided,  however,  by  the  ns< 
of  a  tenter  frame. 

Geon  latex  is  a  true  colloidal  dispersion  in  water  of  a  vinyl 
chloride  type  polymer.  It  is  described  as  a  latex  Ix-caiisc 
it  contains  uniform  spherical  particles,  about  0.2  micron  ir 
diameter,  suspended  in  water.  The  charge  on  the  particles  it 
negative.  Stability  is  obtained  by  virtue  of  the  small  parti- 
cle size  and  the  presence  of  small  amounts  of  stabilizing 
materials.  The  latex  is  most  stable  in  an  alkaline  medinn 
and  will  remain  stable  indefinitely  if  the  pH  is  kept  adjusted 
to  8.5  by  the  use  of  ammonia.  Under  some  conditions  it  car 
IK-  kept  for  many  days  or  weeks  without  coagulation  at  pH 
values  as  low  as  3.  It  can  be  coagulated  by  electrolyte 
solutions,  but  weak  acids  (e.  g.,  acetic  acid)  and  salts  like 
sodium  chloride  are  relatively  ineffective.  Freezing  will 
also  bring  about  coagulation. 

Since  the  particles  of  Geon  latex  are  of  colloidal  dimen- 
sions, they  exhibit  rapid  Brownian  motion  and  do  not  settle 
out  on  long  standing.  Centrifuging  or  ordinary  filtratior 
methods  produce  no  separation.  Small  particles  also  help  to 
bring  about  good  penetration  of  fibrous  materials. 

A  dry  loose  powder  is  normally  obtained  when  the  latex 
is  dried  at  room  temperature.  Under  proper  conditions, 
however,  it  will  form  a  strong  continuous  film  of  material. 
Good  coalescence  of  the  dispersed  resin  is  attained  by  proper- 
ly adjusting  plasticizer  concentration  and  subjecting  the 
latex  compound  to  systematic  drying  procedures. 

As  with  all  vinyl  resins,  correct  heat  treatment  is  essential. 
The  application  of  heat  to  a  latex-treated  material  serves 
two  purposes.  It  evaporates  the  water  from  the  resin  and 
causes  fusion  of  the  resin  particles,  resulting  in  a  continuous 
homogeneous  deposit.  As  the  result  of  the  heat  treatment, 
the  appearance  of  the  material  should  change  from  milky  to 
transparent,  indicating  continuity  of  structure.  This  clear- 
ing of  the  film  serves  as  a  convenient  visual  indication  of 
complete  water  removal  and  film  fusion. 

Formulation  of  "Geon"  Latex  Compounds 

Formulation  technique!  are  quite  simple.  1'lasticizers, 
extending  pigments,  colors,  and  waxes,  usually  in  dispersed 
form,  are  added  to  the  latex  to  impart  certain  desired  proper- 
tu-s  to  the  finished  product. 

The  same  types  of  plasticizers  used  with  dry  polyvinyl 
resins  can  be  used  in  compounding  latex.  The  technique  in 
the  addition  is  the  only  variation.  With  the  latex  method, 
plastici/ers  are  added  as  concentrated  emulsions  of  the  oil- 
in-water  type.  Colloid  mills  are  very  efficient  in  the  prepara- 
tion of  such  emulsions. 

I  \tending  pigments,  colors,  and  other  solid  materials,  be- 
fore being  incorporated  into  the  latex  coni|>ouii<ls.  should 
be  carefully  dispersed.  In  the  addition  of  solid  dis|>ei  v,,,ns, 
.1  very  unstable  condition,  with  coagulation  prohahly  result- 
ing, would  exist  ii  there  were  a  pronounced  dillerenci-  in 
size  between  the  very  minute  particles  of  latex  and  the  par- 
ticles of  the  solid.  This  would  be  like  mixing  golf  halls 


76 


!•  I. AST  14  s 


Al  (,l  SI    1>M6 


Properties 


'Geon"  Latex 


Values 


Solids  (9f> 

Viscosity  (centipoises  at  20°C). 
Surface  tension  (dynes  per  cm). 

Particle  size  (microns) 

Density  of  resin 

Specific  gravity  (at  25°C) 


54-58 

10-18 

40-46 

17-.22 

1.35 

1.165-1.180 


and  medicine  balls.  To  avoid  instability,  the  solids  must  be 
reduced  in  a  pebble  mill  to  a  size  more  comparable  with  the 
particles  of  the  latex,  preferably  to  between  1  and  5  microns. 
This  makes  for  more  uniform  coating  in  the  end  product. 
At  the  same  time,  the  dispersion  should  be  maintained  slight- 
ly alkaline  by  the  addition  of  ammonia. 

Emulsions  and  solid  dispersions  should  be  mildly  agitated 
during  mixing,  for  which  a  low  speed  paddle  stirrer  is 
recommended.  For  best  control,  plasticizer  emulsions  should 
be  added  to  the  latex  and  this  mixture  aged  for  about  24 
hr  before  any  solid  dispersions  are  blended  into  the  com- 
pounds. 

Often  the  processing  of  materials  with  Geon  latex  com- 
pounds can  be  handled  somewhat  in  the  same  manner  and  on 
the  same  type  of  equipment  as  solvent  solutions  of  vinyl 
resins.  In  paper  and  fabric  coating,  machines  such  as  spread 
coalers,  air  knife  machines,  dip  tanks,  and  roller  applicators 
can  be  used.  Compounds  of  latex  are  also  readily  adaptable 
to  spraying  technique. 

Evaporation  of  the  water  from  a  latex  deposit  should  be 
accomplished  at  about  200°F.  The  resin  deposit  should  then 
attain  a  final  temperature  of  300° F  to  obtain  its  maximum 
physical  properties.  In  normal  processing,  the  drying  and 
fusion  should  be  accomplished  in  one  operation. 


Proper  processing  conditions  are  maintained  by  physical 
tests.  Information  on  properties  such  as  viscosity  and  sur- 
face tension  are  useful  in  determining  the  necessity  for  ad- 
justments in  formulations  as  well  as  in  the  development  of 
new  type  compounds.  For  example,  in  coating  one  type  of 
fabric,  a  different  viscosity  and  surface  tension  will  be  re- 
quired of  a  compound  than  when  coating  fabric  of  different 
texture  and  porosity. 

Tests  for  physical  properties  of  the  finished  articles  are 
the  same  as  for  those  processed  with  solvent  solutions  of 
resin.  END 


Injection  Mold  Design 

(Continued  from  page  24) 

be  located  at  1  or  2.  However,  if  the  gate  is  at  3,  the  air 
will  be  pushed  ahead  of  the  incoming  material  to  the  rims 
where  it  can  be  easily  vented,  thereby  eliminating  danger 
of  trapping  air  in  the  disc  portion.  Therefore  3  would  be 
the  correct  location  for  the  parting  line  on  this  piece. 

Sometimes  on  irregular  shapes  the  normal  flat  parting 
line  cannot  be  used.  The  piece  design  is  often  such  that  no 
plane  surface  can  pass  through  the  part  in  such  a  way  as 
to  eliminate  all  undercuts  and  side  projections  which  will 
not  pull.  In  this  case  an  irregular  parting  line  is  necessary. 
This  greatly  increases  mold  cost,  as  the  irregular  parting 
surfaces  must  be  carefully  fitted  together  before  and  after 
heat  treating  so  that  material  will  not  flash  out  of  the  cavities 
along  the  parting  line,  and  thus  require  expensive  trimming 
after  molding. 

The  toothbrush  handle  (Fig.  9a)  requires  an  irregular 
parting  line  because  of  the  bent  handle. 

The  hinge  on  the  box  shown  in  Figure  9b  could  not  be 


foe 


When  it  comes  to  the  question  of  the  RIGHT 
molding  job  we  have  the  answers  as  to  what 
plan,  material  and  mold. 

K  &  J  is  a  controlled  service  in  every  detail. 
Experience  is  back  of  every  effort  and  the  result 
is  a  molded  piece  that  fits  the  particular  condi- 
tion for  which  it  was  intended. 

Confer  with  K  &  J  engineers  —  our  knowledge 
will  help  in  your  future  molding  problems. 


TRADE    MARK 


KUHR  &  JflCOB  mOLDIM  &  TOOL  CO. 


1200    SOUTHARD   STREET.   TRENTON    8.    N.  J. 
TELEPHONE  TRENTON*  5391 

Sales   Representatives:     NEW  YORK— S.  C.  Ullman,  55  W.  42nd  St.  PHILADELPHIA— Towle  &  Son  Co.,   18  W.  Chelton'Ave.   Bldg. 

NEW  ENGLAND— Wm.  T.  Wyler,   177  State  St.,   Bridgeport.  Conn. 


£aAfu>  C/K^ccWyia' J/ 


<7 


AUGUST  1946 


PLASTICS 


77 


.Voir  available  m  many 

CO /os 
/or  ettry  f 


Tb*rt  it  only  tnt  [>t-tiiif 
—CELLO-PLASTIC. 


Brings  New  Colorful  Beauty  and  Durable  Protection  to 
r LOOKS  *  WOODWORK  it  WALLS  *  EXTERIORS 

oils  combined  with  the  finest 
paint  pigments.  ACello- Plastic 
product  is  available  for  almost 


Plastic  is  now  prepared  in 
liquid  paint  form  for  use  in 
horn  e,  office,  store,  and  factory. 
This  has  come  about  through 
(he  formulation  of  synthetic 
resins  with  specially  processed 


any  type  of  finish  or  surface. 
Does  not  chip  or  crack! 
BRILLIANT  +  SMOOTH  *  TOUGH  *  DURABLE 

COD  FLOORS  Cello-Plastic  ^transparent/  is  i  awn-iaW  plastic 
«****•»«»  finish  for  all  tvpes  of  floor*.  Tim  imaiing  new 
treatment  give*  floors  a  "cellophane-like"  Plastic  finish.  Fliminates  pores  that 
absorb  dirt,  thuf  miking  floor*  em  to  clean.  Ideal  for  all  surfaces  including 
wood,  concrete,  linoleum,  asphalt,  tile  rubber,  composition,  etc.  I  limriutn 
MxMf  *m/  pflnAni.  Uneicelled  for  marine  use. 

EXTERIOR      ' h"  modern  finish  is  •  severely  tested  product 
L     that  surpasses  old  fashioned  type  house  paints. 

Pigmenird  with  Titanium  Dioxide,  the  whitest  and  best  covering  pigment, 
combined  with  kettle  processed  linseed  oils  and  plastic  resins,  it  makes  a  rich, 
colorful,  latiina  coaling.  Makes  homes  and  buildings  outstanding.  For  use  on 
wood,  stucco,  brick  or  shingle. 

INTERIOR     "rings  new  glamour  into  homes — protect  Boors. 
k     woodwork,   furniture,  etc..  with  its   long-lasting. 

cellophane-like"    Plastic  finish.   Easy  to  apply — Hows  smoothly — leave*  no 
brash  marks— s*lf  leveling. 

Inquiries  from  Exporters  and  Dealers  Solicited 

ProJuct  liability  *mltruvittt*  by  on*  of  Amrrift't 
Urgttl  itanromct  comptniti. 


CELLO-PLASTIC  CHEMICAL  CO. 

417-419  BLVD.  OF  ALLIES,  PITTSBURGH  19,   PA. 


/=>»-.       9- A 


9-B 


molded  with  a  die  having  a  flat  parting  >url"ace.  Here  tin- 
line  must  run  along  the  top  of  the  box.  and  then  drop  down 
to  the  centerline  of  the  hinge  boss. 

Before  the  mold  design  is  considered  complete,  eyebolt 
holes  should  be  specified  on  the  top  side  of  the  mold  to 
assist  in  lifting  the  mold  into  place  in  the  press  with  a 
chain  hoist.  Also  the  mold  should  be  stamped  plainly  with 
part  and  tool  numbers,  date  of  manufacture,  and  any  other 
pertinent  data  which  may  later  be  of  a->i>tance  in  identi- 
fying it  in  mold  storage.  All  parts  should  be  stamped  with 
the  grade  of  steel  used  in  case  the  part  has  to  be  replaced 
or  altered  at  a  later  date.  Cavity  number  and  molder'.* 
trademark  should  appear  on  all  molded  pieces  if  the  cus- 
tomer's permission  can  be  obtained.  The  cavity  number 
helps  to  identify  quickly  which  cavity  has  been  damaged  if 
the  inspector  reports  bad  work  coming  from  the  mold,  and 
the  molder's  trademark  eliminates  arguments  as  to  who 
made  the  rejects  in  case  the  customer  has  split  his  production 
between  two  or  more  molders,  as  is  often  the  case  on  large 
production  items.  END 


NOTE:  This  is  the  final  installment  in  the  series  of  articles  on  injection 
mold  design.  The  September  issue  of  Plastics  will  begin  a  new  series  on 
compression  mold  design  by  the  same  author. 


Mo  d  em  izin  g  In  strum  en  f  s 

(Continued  from  page  52) 


products  to  the  plastics  kind,  and  we  feel  it  will  be  good 
business  to  follow  this  trend. 

A  good  illustration  of  this  is  our  all-plastics  T-square, 
which  makes  it  possible  to  accomplish  many  drafting  ta-k- 
without  the  use  of  auxiliary  tools.  That  is,  the  head  of  the 
T-square  is  graduated  so  that  it  can  be  used  as  a  protractor. 
The  arm  can  be  used  as  a  straight  edge,  and  the  head  can 
accommodate  different  length  arms.  Contrasted  with  thr 
wooden  and  metal  types,  it  is  less  cumbersome  to  use,  I<-^- 
costly  to  ship,  much  more  attractive,  and,  most  important, 
speeds  up  the  job  at  hand.  The  consumer  pays  no  more  for 
the  plastics  instrument  than  for  the  less  efficient  kind. 

The  choice  of  the  proper  plastics  to  use  in  manufacturing 
a  particular  instrument  depends,  of  course,  on  the  function 
of  the  instrument.  For  example,  at  first  we  experimented 
with  cellulose  acetate  for  the  head  of  the  T-squarc  men- 
tioned above.  However,  later  we  decided  that  acrylics 
would  be  more  suitable  for  this  purpose  because  of  their 
greater  dimensional  stability.  Even  then  we  had  to  have  a 
special  formulation  made  up.  In  choosing  a  plastics  for  our 
regular  protractor,  we  decided  upon  cellulose  nitrate,  since 
it  is  easy  to  work  and  dimensional  stability  is  not  so  im- 
portant as  for  the  T-square  head.  The  reason  for  this  is 
that  if  a  slight  change  in  the  dimensions  of  the  piece  oc- 
curs, the  accuracy  of  the  angles  is  not  altered,  since  the 
change  is  uniform  in  all  direction'-. 

The  almost  unanimous  public  acceptance  and  interest  in 
pla^tir-  drawing  instruments  indicates  a  bright  future  for 
those  companies  in  any  line  which,  having  firmly  believed 
in  plastics,  have  had  the  patience  to  make  their  merits 
known  to  the  ultimate  user.  F.NH 


78 


f» I.  t  ft IT  f  1  * 


AUGUST  194fi 


In  process  of  replacing  worn-out  frames  with  laminated 
ribs,  after  first  ply  is  cold  bent  and  attached  to  the 
hull  by  screws,  "Urac  185"  is  put  on  to  hold  second  ply 


A  New  Method 
of  Repairing 
Sailboats 


AN  ATLANTIC  class  racing  sloop  was  recently  repaired 
at  a  minimum  of  expense  and  a  maximum  of  struc- 
tural strength  by  the  installation  of  three-ply  laminated 
frames  which  were  joined  with  a  new  urea-formaldehyde 
resin  adhesive  called  Urac  185.  These  frames  were  to  re- 
place the  worn-out  frames  or  ribs  which  support  and  give 
form  to  the  hull. 

Though  Atlantic  class  sloops  have  a  reputation  for  dura- 
bility, they  are  said  to  suffer  a  common  structural  failure  in 
the  breaking  of  their  steam-bent  oak  reinforcing  frames. 
In  the  past,  two  standard  methods  were  used  for  repairs. 
One  was  to  affix  sister  frames  of  oak  alongside  the  break  in 
the  original  frame ;  the  other  was  to  tear  out  the  entire 
structure  and  replace  it  with  new  bent  oak  frames. 

The  disadvantages  of  the  old  repair  methods  led  to  the 
present  story.  Navy  Lt.  Albert  Young  was  stationed  near 
his  Long  Island  home  last  year,  which  enabled  him  to  spend 
his  week-ends  in  racing  his  sloop  Rhapsody  to  his  club's 
championship  in  its  class.  When  the  season  closed,  it  was 
found  that  repairs  were  needed.  Young  then  decided,  as  the 
result  of  the  shortcomings  of  the  old  methods  and  of  his  ex- 
periences with  PT  boats,  where  resin-bonded  plywood  had 
proved  so  successful,  to  use  the  new  method  of  laminating. 

In  this  method,  •}£"  elm  frames,  1}4"  wide,  are  sawed  and 
cut  to  size.  The  first  ply  is  cold  bent  to  the  contour  of  the 
boat  and  is  held  in  place  by  J^"  brass  screws.  The  resin 
adhesive  is  then  smeared  on  the  face  of  the  elm  frame.  The 
second  frame  is  applied  against  the  first  veneer  and  fastened 
into  place  by  the  i/i"  brass  screws.  The  same  technique  is 
followed  with  the  third  ply.  These  fastening  screws  are 
placed  about  6"  apart  throughout  the  length  of  the  ply.  The 
entire  structure  is  then  fastened  from  the  outside  through 


*o 


We're  operating  over  capacity 
right  now — have  been  for 
months — yet  when  a 
manufacturer  comes  to  us  for  an 
especially  good  job  in  plastics 
molding — we  haven't  the 
heart  to  say  "NO"! 

We  do  have  a  definite  pride 
in  our  craftsmanship 
— which  makes  a  challenge  of 
every  job  that  comes  our 
way  no  matter  how  busy  we  are. 
That  is  undoubtedly  the  reason 
so  many  manufacturers  call 
upon  us  in  the  first  place. 

So  send  along  your  sample 
product  or  blueprint  and  we'll 
give  you  the  benefit  of  honest, 
experienced  advice  at  least, 
and,  if  possible,  the  satisfaction  of 
a  Continental  "turned-out"  job. 


CONTINENTAL 

PLASTICS  CORPORATION 

308  WEST   ERIE   STREET 
CHICAGO   10,  ILL. 


AUGUST  1946 


PLASTICS 


79 


Practical  TO  Ineipemive,  ihii  drill 
ji|  ia  aimple  and  eaaily  operated. 
injuring  increased  production  and 
lower  tooling  coat.  It  ia  De-S«a>Co 
Clamp  No.  2O7-U. 

There's  an  exact  type  and  site  of  De-Sta-Co  Clamp 
for  holding  any  plastic  part  securely  in  fixture 
during  production  or  assembly. 

Positive  pressure  is  gently  and  uniformly  applied 
—  automatically  maintained  —  instantly  released. 

Simplify  the  building  of  jigs  and  fixtures.  Aid 
in  securing  maximum  accuracy  in  drilling,  grind- 
ing, sawing,  gluing,  milling,  and  other  operations 
where  precision  is  vital. 

New  De-Sta-Co  Catalog  No.  45  describe* 
.HI.  I  iffuxtuiri  DexStu-Co  Clamfa  —  ntggetu 
time  Hiving  <jf>f>/iculioru  —  Send  for  copy. 


ca 


the  planking  to  the  new  rib  or  frame  with  iy2"  silicon 
bronze  screw-. 

Young  states  that  the  technique  is  convenient  for  one  man, 
and  that  the  resin  it-elf  is  ea-y  to  apply  and  sets  without 
either  heat  or  pressure  into  a  permanent  bond.  Further- 
more, with  the  new  resin  the  elm  frames  do  not  require 
exact  fitting  and  finishing. 

The  adhesive,  a  product  of  American  Cyanamid  Com- 
pany, is  said  to  be  a  modified  and  improved  version  of  re-ins 
known  as  Beetle  cements  which  were  developed  by  the 
British  for  use  in  wooden  aircraft  construction  during  the 
war.  The  essential  advantage  claimed  for  Urac  185  over 
other  resin  glues  is  that  it  can  be  used  successfully  for  ^luc 
lines  up  to  .020"  in  thickne-s  without  danger  of  cracking  or 
crazing.  Because  of  these  non-crazing  properties,  it  i-  not 
necessary  for  joints  or  surfaces  to  be  perfectly  machined: 
they  can  be  glued  just  as  the  wood  comes  from  the  -aw. 
The  resin  also  provides  a  water-resistant  glue  line  and  is 
resistant  to  attack  by  fungus. 

Young  is  said  to  feel  that  resistance  of  the  adhesive  to 
salt  water  and  incident  exposure  to  the  elements,  beside-  tin- 
properties  already  named  and  the  natural  strength  advan- 
tages attained  by  a  laminated  structure,  gives  the  best  po— i- 
ble  insurance  against  future  frame  breakdown-.  KM> 


Class  Resin  Laminates 

(Continued  from  page  70) 


The  laminated  glass  plastics  compares  favorably  to  nm-t 
structural  metals  except  for  modulus  of  elasticity.  With  a 
lower  modulus  of  elasticity,  the  laminates  will  deflect  more 
than  the  metals,  but  this  lack  of  stiffness  can  be  overcome 
by  proper  product  design. 

Thermal  effects  on  strength  properties  of  materials  are 
important,  for  they  show  the  temperature  range  at  which 
the  materials  can  be  properly  used.  The  strength  of  the 
laminate  increases  at  sub-normal  temperatures  and  de- 
creases at  elevated  temperatures.  Most  plastics  materials 
follow  this  same  trend  but  have  a  reversed  relation  for  im- 
pact strength,  being  brittle  at  low  temperatures.  With 


Arc  teel  on  a  qlau  fiber  melamine  retin  panel  board 

PLASTICS  AUGUST  1'Uii 


glass-melamine  resin  laminates,  however,  the  impact 
strength  is  high  at  subnormal  temperatures  and  low  at  ele- 
vated temperatures. 

The  effect  of  thermal  aging  on  properties  of  materials  is 
also  important  since  it  indicates  the  length  of  time  they  can 
be  used  at  elevated  temperatures. 

The  insulation  resistance  of  glass  base  melamine  resin 
laminates  decreases  quite  rapidly  when  the  material  is  ex- 
posed to  high  humidity.  Also  the  glass  melamine  laminate 
absorbs  more  water  than  the  glass  phenolic  laminate. 

Properties  Differ 

It  is  important  to  point  out  the  properties  of  melamine 
resin  laminates  made  from  different  reinforcing  materials. 
Glass  fabric  laminates  have  higher  tensile,  flexural,  com- 
pressive  and  Izod  impact  strength  than  laminates  made 
from  asbestos  fabric,  cotton  fabric,  or  kraft  paper.  The  arc 
resistance  of  the  glass  fabric  laminates  is  higher,  which 
proves  that  high  arc  resistance  of  glass  fabric  melamine 
resin  laminates  is  due  to  the  combination  of  these  two  ma- 
terials and  not  a  function  of  the  resin  alone.  The  out- 
standing differences  between  glass  fabric  laminates  made 
from  melamine  resin  and  from  phenolic  resin  is  the  arc  re- 
sistance and  flame  resistance.  Phenolic  glass  base  laminates 
have  an  electrical  arc  resistance  approximately  10  sec  as 
measured  by  the  ASTM  method,  whereas  melamine  resin 
laminates  have  values  over  180  sec.  END 


ui mi i 


New  Mix  for  Castings 

{Continued  from  page  56) 


veloped  that  the  completed  dies  did  not  perform  satisfac- 
torily because  of  springback  of  the  aluminum  sheet.  As  <, 
result,  the  dies  often  had  to  be  re-worked  or  scrapped. 
Hydromite  was  tried  in  a  test  die  to  determine  whether  its 
planned  metal  prototype  would  perform  the  intended  job. 
After  the  die  was  "proved,"  it  was  reproduced  in  metal  for 
permanent  use.  but  in  the  meantime  the  Hydromite  die  was 
kept  in  production. 

Repair  with  Hydromite 

In  more  than  one  instance,  damage,  breakage,  or  model 
changes  stopped  production  until  a  new  die  could  be  fabri- 
cated. The  method  of  getting  back  into  production  quickly 
with  Hydromite  tools  is  best  illustrated  by  a  production 
stoppage  due  to  a  broken  hydropress  die.  The  break  oc- 
curred on  a  die  for  a  part  vitally  needed  to  prevent  a  shut- 
down of  the  entire  production  line.  The  normal  time  for 
molding,  casting,  and  hand  finishing  the  metal  die  was  four 
days.  As  soon  as  the  die  broke,  the  broken  halves  were 
filled  in  with  modeling  clay  to  form  an  unbroken  surface. 
The  surface  was  then  lubricated  with  a  thin  film  of  stearic 
acid-kerosene,  and  a  mix  of  gypsum  cement  was  applied  to 
form  a  mold  of  the  die.  As  there  was  some  undercut  on  the 
sides  of  the  die,  it  was  necessary  to  make  a  two-piece  mold 
to  permit  separation  of  the  mold  from  the  die  without  break- 
age. The  mold  was  then  reassembled,  and  the  joints  were 
filled  in  with  gypsum  cement  to  obtain  an  unbroken  mold 
surface. 

After  treating  the  mold  cavity  with  stearic  acid — kero- 
sene parting  compound,  a  mix  of  100  parts  of  Hydromite 
to  17  parts  of  water  by  weight  was  prepared.  A  small 
amount  of  the  mix  was  poured  into  the  mold  and  brushed 
to  release  trapped  air  and  completely  coat  the  faces  of  the 
mold  cavity.  The  mold  was  then  completely  filled. 

After  the  resin  material  hardened  sufficiently  (about  30 
min)  the  die  was  removed  and  transferred  to  a  curing  oven 


IMMEDIATE 
DELIVERY 


Standardized 


Ejector  Pins 

SAVE 

MONEY,  TIME, 

BREAKDOWN 

TROUBLE! 

These  standardized  pins  are  much 
lower  in  cost,  much  higher  in  qual- 
ity than  toolroom-made  ejector  pins 
for  plastic  molding.  They  will  save 
you  money,  time  and  breakdown 
trouble.   Made   of   Nitralloy   steel, 
core  toughened  by  heat  treating, 
super-hard    nitrided    case.    Many 
sizes — Vi  to  3/4"  diameter,  any 
length    desired.    Perfectly   round, 
straight,  true  to  size  — ALWAYS! 
Longest     wearing,     most     satis- 
factory ejector  pins  known. 


TODAY 


MAIL 
THIS 


FOR  OUR  LOW  PRICES 
AND  FULL  DETAILS 


HeocW 


Threaded 


Detroit  Mold  Engineering  Co., 

6686  E.  McNichols  Rd.,  Detroit  12,  Mich. 

Please  mail  me  your  price  and  specification  folder  on  ejector 
pins  for  plastic  molding. 
I  desire: 

D  CHECK  HERE  WHICH  |"""1 

FOLDER  YOU  DESIRE 

(Headed)  (Threaded) 

Name 

Company 

Address  .  . 


r     DETROIT      MOLD 
ENGINEERING     COMPANY 


6686   E.   McNICHOLS   RD. 


DETROIT    12,   MICHIGAN 


AUGUST  1946 


PLASTICS 


81 


maintained  at  110°  F.  The  following  morning  the  die  was 
put  into  production  where  it  was  ux-tl  until  the  metal  die 
was  completed  three  days  later.  At  that  time  the  Hydro- 
mite  die  was  put  into  storage  as  a  reserve  in  the  event  of 
another  failure. 

In  mixing  Hydromite.  weighed  amounts  of  both  the  ma- 
terial and  the  water  must  be  used  to  obtain  accurate  and 
consistent  results.  A  recommended  mix  is  100  parts  of  ma- 
terial to  16-17  parts  of  water,  each  by  weight.  If  a  mix  is 
desired  for  greater  strength  and  hardness,  the  water  con- 
tent may  be  reduced  to  13-14  parts.  The  resin  material 
should  be  added  to  the  water  and  immediately  mixed,  pre- 
ferably with  a  confectioner's  wire  whip. 

In  order  to  insure  a  good  reproduction  and  avoid  trapped 
air,  a  small  quantity  of  mix  is  poured  into  the  mold  and 
forced  into  the  detail  by  rubbing  or  brushing.  A  mold  dress- 
ing or  wetting  agent,  used  according  to  the  manufacturer's 
directions,  leaves  a  wet  film  on  the  mold  face  and  permits 
complete  filling  of  detail  with  minimum  brushing  and  vibra- 
tion. The  mold  dressing  breaks  the  surface  tension  of  the 
water  in  the  plaster.  Dreft  is  one  of  the  more  common 
materials  which  can  be  used  for  this  purpose. 

Development  Stage 

Hydromite  develop*  Mrcngth  in  two  stages.  During  the 
first  10-15  minute-  it  retain-  its  syrupy  con-i-tency.  Tlii- 
i*  followed  by  a  JO-3O  minute  hardening  period,  during 
which  it  develops  sufficient  strength  to  permit  separation 
from  the  mold  or  model.  It  heats  and  expands  slightly 
while  thi-  hardening  occurs,  and  separation  is  easier  it" 
made  during  this  period  of  maximum  heat  and  expan-ion. 

The  "hardening"  is  followed  l>y  a  "curing  period."  The 
curing  varie-  with  the  size  of  the  cast  and  the  curing  tem- 


peratures, which  should  never  exceed  150°  F.  When  u-m- 
peratures  of  150°  F  are  exceeded,  the  product  is  weakened. 
Hydromite  may  be  poured  or  injected  with  air  pressure,  but 
it  can  not  be  screeded.  It  can  be  cast  into  any  synthetic 
rubber  or  plastics  mold,  but  glue  molds  can  not  be  used  be- 
cause they  are  destroyed  by  the  heat  which  Hydromite  skives 
off  in  curing.  K.XD 

Physical  Properties  of  Cast  "Hydromite" 

Specific  gravity 

After  3  hr 1 .82- 1 .85 

Cured 1 .74- 1 .78 

Density  (Ib  per  cu  ft) 

After  3  hr 1  14-1  1  6 

Cured 1 09- 1  1  1 

Tensile  strength  (psi) 

After  3  hr 750-850 

Cured 1  1 00- 1  200 

Compressive  strength  (psi) 

After  3  hr 6000-7000 

Cured 11 .000- 1  2,000 

Modulus  of  elasticity  ( 1 0<  psi) 

After  3  hr 1 

Cured 1 .9-2. 1 

Modulus  of  rupture  (psi) 

After  3  hr 950- 1 050 

Cured 3400-3600 

Brinell  hardness 

After  3  hr 10-11 

Cured 21-23 

Water  absorption  ('  f  on  48  hr  immersion  at  room  temperature) 4-5 

Dimensional  change  (in.  per  in.) 

In  hardening  (expansion) 0.001  2-0.001  5 

In  curing  (shrinkage) 0.004-0.005 

Net  change  (shrinkage) 0.0025-0.0035 

Color Light  blue 

Typical  r*wlti  shown  ore  based  oo  cattt  mod*  at  1 7  consistency  ( 1 7  parts  water  to  1 00 
parii  "Hydromite"  by  weight).  "3  hour"  results  ore  on  costs  three  hours  old  from  time 
of  mixing  and  subjected  to  room  temperature  (70°  f)  during  the  three-hour  period. 
"Cured"  indicates  results  on  completely  cured  casti. 


CONVERT    YOUR     HYDRAULIC     PRESS     INTO    A 

VERTICAL  PLASTIC  INJECTION 
MOLDING  PRESS  IN  A  FEW  HOURS 

Unit  is  easily  removed  and  your  press  reconverted  to  a  hydraulic 
press.  We  require  the  dimensions  of  your  press  between  posts, 
front  to  back,  and  left  to  right,  daylight,  size  of  ram,  and  ram 
pressure  used. 

The  following  chart  will  show  the  capacity  of  your  press  at 
30,000  psi  injection  pressure. 


Tom 

Oz. 

Molding  area  sq.  in. 

50 

2 

7  to    20 

75 

3 

10  to    30 

100 

4 

15  to    40 

ISO 

6 

20  to     60 

200 

8 

25  tc     80 

250 

10 

30  to  100 

300 

12 

40  to  120 

400 

16 

60  to  ISO 

FLUID  POWER  AIR  OPERATED  PUMP 

I8S  gallons  per  minute  at  200   pti   3000   psi   accumulated   pressure   cuts 

in  at  200  pounds  automatically.    Unit  it  in  a  tteel  cabinet  with  all  the 

controls  on  the  front  panel. 

400  ton  HY  SPEID  pnu  wrfh  36 '.32'  P/oferu,  42'  do/. 
lioM,  pufon  type  ram  Converted  inlo  o  24  01.  (n/ecn'on 
•ocnine  of  a  coif  of  $6500  lor  complete  conversion 

*    OUR  2  OZ.  INJECTION  MOLDING  MACHINE  CAN   BE  HAD  IN   30  DAYS.  WRITE  NOW. 


1715  W.  Lake  St. 


HY-SPEED  PRESS  COMPANY 

Chicago  12.  Illinois 


Haymarket  3161 


82 


PLASTICS 


AUGUST  1346 


Slitting  Film 
to  Size... 


Knives,  shown  at  operator's  left  hand,  may  be  set  to  slit 
a  film  or  coated  fabric  to  any  width  from  tape  size  on  up 


Complete  service  includes  fold 
straightening,  bolt  making  and 
interleaving  -with  paper  sheets 


SLITTING  and  cutting  of  plastics  films  and  coated  fabrics 
to  widths  other  than  standard,  is  now  being  done  on  a 
commercial  basis  by  Cee-Bee  Mfg.  Co.  of  Brooklyn,  N.  Y. 
In  conjunction  with  this  service,  the  company  also  straight- 
ens out  folds  in  the  material  and  interleaves  it  with  paper 
to  prevent  the  layers  of  film  from  adhering  to  one  another 
during  shipment. 

Interleaving  serves  a  further  useful  purpose  where  many 
layers  of  the  film  are  to  be  cut  at  one  time,  as  in  making 
raincoats.  In  this  operation,  the  interleaves  act  as  heat  in- 
sulators against  the  heat  generated  by  the  knife  action,  and 
thus  serve  to  prevent  the  layers  of  material  from  binding 
and  being  ruined. 

The  slitting  service  is  also  of  importance  to  mills  turning 
out  a  75"  width.  For  instead  of  calendering  a  36"  sheet, 
they  can  produce  one  more  than  twice  as  wide  and  have  it 
slit  afterwards,  as  a  great  production  economy.  Cee-Bee 
receives  the  material  in  bulk,  trims  it  and  cuts  it  in  any 
assortment  of  widths.  It  also  divides  the  original  shipment 
into  bolts  of  the  desired  length,  which  it  then  will  forward 
to  the  end  purchaser  if  doing  so  is  in  accordance  with  the 
wishes  of  the  material  supplier. 

One  of  the  greatest  calls  for  this  type  of  service,  accord- 
ing to  Charles  Bukowsky,  general  manager  of  Cee-Bee,  is 
for  the  making  of  industrial  tapes.  The  garment  trades 
especially  have  a  great  outlet  for  them  in  the  binding  of 
curtains,  items  of  clothing,  draperies,  shoes,  and  so  on. 

The  machinery  used  in  the  operation  is  similar  to  the 
conventional  slitting  machines  used  in  related  industries,  but 
is  adapted  to  the  special  characteristics  and  nature  of  plas- 
tics materials.  END 


Profit   NOW   fay  using 
or  selling  genuine 


LIQUID  PLASTIC  PAINTS 

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are  here  TODAY  —  for  home  and  industry! 
Cello-Nu  liquid  plastic  coatings  are  self- 
leveling,  fast-drying  .  .  .  flow  off  the 
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ONE  COAT  COVERS. 

•  ALL-PURPOSE  &  Furniture  Finish! 
•  INTERIOR  Gloss,  Semi-Gloss,  Flat! 
•  FLOOR,  Porch  &  Concrete  Colors! 
•  TRANSPARENT  for  all  surfaces! 
•  EXTERIOR  liquid  plastic  paints! 
•  AUTOMOBILE  finishes 
•  EverPlastic  MARINE  Paints! 
•  EverPlastic  LEATHER  COATINGS! 

* 


PLASTIC  PRODUCTS  DO 
YOU   HAVE   FOR   DISTRIBUTION? 

We  have  the  ORGANIZATION  and 
SHOW  ROOMS  to  speed  sales  of 
PLASTIC  floorings,  wall  coverings, 
decorative  items  and  other  plastics 
for  the  home.  Our  jobbers  and  deal- 
ers, inspired  by  the  success  of  Cello- 
Nu  paints,  are  ready  to  promote  your 
items  with  the  same  energetic  ap- 


proach. 


Cello-Nu  Prodi 

875  Sixth  Ave. 
NEW  YORK,  N.  Y. 


AUGUST  1946 


Vt.ASTMCS 


83 


INDUSTRY  HIGHLIGHTS 


Brush  stud  insulators  for 
d-c  motors,  formerly  molded 
with  a  laminated  insert,  are  now 
compression  molded  in  one  part, 
in  a  positive  mold,  by  the  Gen- 
eral Electric  plastics  divisions. 
This  change  to  a  single  mold- 
ed part  was  accomplished  by 
turning  to  an  impact  material 
which  permitted  the  molding  of 
relatively  thin  walls  to  close 
tolerances. 

The  impact  material  supplies 
the  necessary  strength  to  the 
hubs  of  the  insulators,  while 
the  ability  to  mold  to  exacting 
tolerances  makes  it  possible  for 
the  hubs  to  fit  snugly  one  inside 
the  other. 

The  parts  are  made  in  vari- 
ous sizes,  and,  according  to  the 
company,  represent  a  marked 
reduction  in  cost  and  a  decided  increase  in  efficiency  as  com- 
pared to  the  method  formerly  used. 


proof  compounds  for  flameproofing  and  mildew-proofing  fabrics, 
a-,  well  as  making  them  waterproof.  The  compounds  were  de- 
veloped by  the  Pittsburgh  company's  staff. 

Two  principal  types  of  the  product  are  being  marketed:  l\-r- 
mafrmij  l(k>  series,  designed  chiefly  for  treating  outdoor  protec- 
tive materials  such  as  tents,  awnings,  etc. ;  anil  the  second  type, 
to  be  known  as  Permaprooj  200  series,  for  curtains,  draperies, 
rugs,  uphwlstery,  and  other  fabrics  for  interior  use. 


The  tool  and  die  division  of  Lester  Engineering  Co.,  i 
land,   ha>    recently    hcen    reorganized   under   the  name  of   'Die 
Letter-  \etna   I  >ie  >  <>.  and  moved  to  Warren,  ().     Facilities  at 
the  new   location  have  been  considerably  expanded,  it   is  an- 
nounced, in  skilled  personnel  and  in  tool  room  equipment. 

Officers  of  the  new  company,  which  is  jointly  owned  by  ! 
Engineering  Co.  and  Aetna-Standard  Engineering  Co.,  of  War- 
ren, are:  Nathan  Lester,  president;  H.  Gerald  CoflFey  and  D. 
White,  vice  presidents;  and  Lloyd  L.  Dalbey,  secretary-treasur- 
er. No  change  has  been  made  in  the  organization  or  basic 
operations  of  Lester  Engineering  Co.  as  producer  of  the  Lester 
line  of  injection  molding  machines  and  die  casting  machines. 


Joint  announcement  has  been  made  by  The  B.  F.  Goodrich 
Co.,  Akron,  O.,  and  Treesdale  Laboratories,  Inc.,  Pittsburgh, 
that  the  first-named  company  will  manufacture  and  sell  Perma- 


A  building  material  described  as  being  lightweight,  eco- 
nomical to  use.  and  possessing  high  strength  has  been  announced 
by  Reynolds  Metal  Co.  The  new  product,  called  Rfynalilt, 
consists  of  two  sheets  of  aluminum,  bonded  with  a  plastics  ad- 
hesive to  a  cellulosic  core,  forming  a  panel  which  is  said  to  be 
impervious  to  moisture  and  to  temperature  changes.  The  mate- 


More 


ACCURATE 
Service. 


and  we  mean  it  ...  BECAUSE  ...  in 
our  NEW  PLANT  we  have  loads  of  extra 
elbow  room  .  .  .  AND  a  larger  staff  of 
competent  engineert  and  designers  .  .  . 
there  are  a  greater  number  of  expert  crafts- 
men .  .  .  AND  TOO  there  it  our  usual  high 
standard  of'quality  production  .  .  .  ALL 
UNDER  ONE  BIG  ROOF.  This  means 
.  .  .  more  ACCURATE  SERVICE  to  meet 
the  accumulated  needs  of  our  many  cus- 
tomers' Compression  and  Transfer  Molding 
Jobs  .  .  .  AND  PERHAPS  .  .  .  your  prob- 
lem too  .  .  .  why  not  call  us  to-day  .  .  . 
NO  OBLIGATION. 


ACCURATE 


MOLDING  35-20    48th    AVENUE 

CORPORATION      LONG  ISLAND  CITY  l.N.Y. 


si 


ri  i 


AUGUST  1946 


rial,  which  can  be  produced  in  large  quantities,  is  adaptable  to 
a  variety  of  major  uses  in  the  construction  and  allied  fields,  ac- 
cording to  its  manufacturer. 


Announcement  has  been  made  of  the  merging  of  Hunger- 
ford  Research  Corp.  with  the  Hungerford  Plastics  Corp.,  the 
organization-  to  continue  under  the  latter  name.  Expanded  op- 
erations at  its  plant  in  Murray  Hill,  N.  J.,  are  to  include  product 
research  and  development,  mold  design  and  manufacture,  ma- 
terial compounding  and  contract  molding. 


Marketed  under  the  name  of  Casco-Resin  135,  a  new  type, 
liquid  urea-resin  glue  has  been  introduced  by  the  Casein  Co.  of 
America,  Division  of  the  Borden  Co.  It  is  made  especially  for 
edge  gluing,  assembly  and  dowel  work  and  is  also  said  to  be 
suitable  for  rotary  clamp  and  general  work. 

According  to  description,  Casco-Resin  135  is  a  free  flowing 
liquid  resin  of  the  urea-formaldehyde  type,  and  is  designed  pri- 
marily for  cold  (room  temperature)  gluing,  setting  or  curing 
of  the  adhesive  being  accomplished  by  addition  of  a  catalyst.  It 
is  also  said  to  be  well  suited  to  low  pressure  gluing,  and  bonding 
of  imperfectly  fitting  joints,  with  resulting  glue  lines,  even  in 
measurable  thickness,  being  craze-resistant,  water-resistant,  mold 
and  fungi-resistant,  and  exhibiting  unusual  strength. 


Incorporation  of  the  company  in  order  to  accommodate  fur- 
ther expansion  of  services  has  been  announced  by  Barnes  & 
Reinecke,  designers  and  engineers,  Chicago. 


Announced  as  a  further  development  of  the  properties  of 
Paraplex  G-25,  Resinous  Products  &  Chemical  Co.  offers  a  new 
plasticizer,  known  as  Paraplcx  G-4Q,  which  is  said  to  possess 
a  number  of  unique  qualities,  and  not  to  be  subject  to  spew, 
migration  or  extraction  by  aliphatic  solvents.  According  to 
description,  Paraplex  C-40  shows  markedly  improved  solvent 
resistance  over  Paraplcx  G-25,  as  well  as  an  appreciably  lighter 


FOR  SALE — Patent  rights,  6  cavity  injection 

type  mold,  in  perfect  condition.     Weight  of 

Alcret  Jigger,  approx.  one  half  ounce. 

We  will  also  furnish  purchaser  with  a  list  of  buyers  now 

wanting  to  buy  this  item,  together  with  the  established 

business. 

THIS  ITEM  RETAILED  FOR  25  CENTS. 
"AKRET"  LIQUOR  JIGGER. 


No  Waste 

No    Spilling 

No    Stained 

Tables 


Accurate 
Measure 

Full 
Contents 

l'/2  Ounce 

Line   Mark 

I  Ounce 


D — Patent    No.    115831 

The  advertising  and  publicity  on  the  Akret  Jigger  has 
been  extensive.  Will  furnish  buyer  with  adv.  cuts,  dis- 
play cuts,  and  other  material. 

Reply  on  Company  Stationery 
Write  to 

H.  B.   KAEMPF   CO. 
Room  809.  320  5th  Ave.,  New  York  City 


WE     BOY 


Thermoplastic  Scrap- 
Rejected  Molded  Pieces 

__  Obsolete    Molding 
Powders-and  pay 

highest  prices 


WE   SELL 


to  tit  your 


needs 


Your  scrap  for  Y°u 
WE  SPECIALIZE  in  cus- 
torn  grinding,  magneto- 
ing,  separating  a 
reworking. 


CELLULOSE  ACETATE  •  POLYSTYRENE  •  METHYL  MET  HACK  YUIE 

A.BAMBERGER 

CORPORATION 

44     HEWES     STREET,     BROOKLYN     11,     N.     Y. 

PHONE:  EVERGREEN  7-3887  •  CABIE:  CHEMPROD  BROOWN 


CELLULOSE  ACETO  •  BUTYRATE 


AUGUST  1946 


PLASTiCS 


POLYVINU  RESINS,  ETC. 


85 


IN  GOLD,  SILVER  OR  COLORS 


•^NORTHERN 


It's  your  custom  molder's  responsibility.  He  must  make 
the  part  right  ...  or  the  product  is  wrong!  When  you 
specify  Northern  you  gain  the  advantage  of  more  than 
37  yean  of  experience  in  producing  plastics  for  all  type 
MMsBblies.  You  are  awured  of  precision  and  uniformity 
for  your  plastic  part,  which  means  quicker,  cleaner  as- 
sembly ...  a  better  all-over  }ob. 


color  and  lower  \i-co.-.hy  at  elevated  temperatures,  hut  exhibits 
slightly  poorer  low -temperature  flexibility. 

Recommended  by  its  makers  as  being  of  especial  iiiten-t  to 
contpoumfelt  of  vinyl  ami  synthetic  rubber  stock  and  for  other 
applications  where  a  polymeric  plasticizer  is  desirable,  Paraplex 
G-40  is  said  to  have  particular  use  in  compounding  specialty 
stocks  such  as  those  used  for  coated  fabrics.  uiiMip]>ortcd  Mieet- 
ing,  adhesives,  oil  and  heat  resistant  gasket  stocks,  etc. 


Recently  announced  by  the  Goodyear  Tire  and  Rubber  Co. 
is  the  availability  of  (iriftred  for  civilian  use.  This  material, 
which  was  used  extensively  by  the  L'.  S.  Navy  during  the  war 
as  a  safety  flooring,  consists  of  an  abrasive  aggregate  in  a  plas- 
tics binder,  and  in  addition  to  its  non-slip  qualities,  is  useful  as  a 
protective  coating.  It  can  be  applied,  according  to  its  descrip- 
tion, to  metal,  wood  or  concrete  by  means  of  trowel,  spray-gun 
or  brush,  and  is  now  available  in  six  colors. 


Removal  of  the  company's  general  offices  and  manufacturing 
plant  to  new  and  larger  quarters  at  2941  E.  Warren  Avc.  lias 
been  announced  by  Schwab  &  Frank,  Inc.,  Detroit. 


The  story  of  completely  automatic  molding  is  told  in  a  full 
color  16  mm  motion  picture  titled  Robots  at  Work,  prepared  by 
V.  ).  Stokes  Machine  Co.  Running  time  of  the  film  is  30  min, 
narration  is  by  Lowell  Thomas. 

Hand  molding,  manually  operated  and  semi-automatic  presses, 
as  well  as  automatic  equipment,  are  shown  in  this  film,  which  also 
depicts  typical  examples  of  moldings  best  suited  to  automatic 
production.  Costs  of  conventional  and  automatic  molding  meth- 
ods on  specific  parts  are  compared,  and  manner  of  determining 
costs  is  shown.  Controls  and  other  mechanism  of  the  automatic 
pr< •", •,  .-ire  described  in  detail.  Prints  of  the  film  are  loaned  by 
the  Stokes  Co.  for  showings  to  engineering  and  industrial  groups. 

Announcement  has  been  made  by  Alien  Property  Custodian 
James  ]•".  Markham  that  complete  files  of  patents  seized  from 
German  and  Japanese  nationals  are  now  available  in  the  patent 
departments  of  the  Chicago  and  Boston  public  libraries  and  at 
the  A  PC's  San  Francisco  office. 


Schwartz  Chemical  Co.,  New  York,  has  announced  the  ap- 
pointinent  i>f  Commercial  Products  Co.,  Ltd.,  of  Toronto,  as  its 
sole  distributor  in  Canada. 

Plans  for  acquisition  of  additional  space  to  accommodate  the 
company's  latest  expansion  program  have  been  announced  liy 
Samuel  Resnic,  treasurer  of  Adams  Plastics  Co.,  Holyoke.  Mass. 
maker  of  I'ack-a-u-ood  knife  handles. 

Established  in  October,  1945,  with  1200  sq  ft  of  space,  the  com- 
pany had  doubled  its  capacity  by  the  end  of  the  year.  A  short 
time  later  it  was  found  necessary  to  increase  the  floor  space  to 
5000  sq  ft,  and  newest  plans  will  add  another  5000  sq  ft.  a-  well 
as  calling  for  nearly  double  the  company's  present  personnel.  Six 
molding  presses  are  to  be  installed  in  the  new  space,  it  is  an- 
nounced, enabling  the  Adams  Co.  to  do  its  own  molding. 


Paper  fibre  rug*  with  improved  resistance  to  water,  wear, 
skidding,  mildew  and  fading  are  forecast  by  Monsanto  Chemical 
Co.,  the  improved  properties  to  be  achieved  by  means  of  coating 
paper  twine  with  vinyl  butyral,  and  then  weaving  the  nig  on 
standard  mill  equipment.  Colors  in  the  base  paper  and  pigments 
permanently  imbedded  in  the  plastics  coating  arc  expected  to 
provide  a  variety  of  color  possibilities,  with  a  multitude  of  de- 
sign possibilities  anticipated 


A  new  location  at  294  Washington  St.  has  IM-CII  announced 

for  the  Host,  .n  otiicr  of  H.  K.   1'orter  Co..   Inc.  which  makes 

equipment  for  the  processing  industries  and  oil  fields  as  well  as 
building  locom..? 


INDUSTRIAL  CHEMICAL  CO. 

38    Yfan    of    P/oific    Molding    Experience 
7.11   IlKINS  ST.,  SO.   BOSTON  J7,  MASS. 

PLASTICS 


The  Institute  of  Design,  Chicago,  has  announced  e\| 
of  its  facilities  to  meet  the  need-  of  in.  n-.iM-d  enrollment.    Con- 
struction and  remodeling  arc  in  progress  on  the  building  former- 
ly occupied  by  the  Chicago   MUtori.  which  lias  been 

acquired  by  the  Institute  as  a  permanent  home  for  it-,  school. 


AUGUST  1946 


P  E  O  P  L  E 


Edward  W.  Schau  and  Charles  A.  Williams  have  been 
named  superintendant  and  assistant  superintendent,  respectively, 
of  the  recently-created  plastics  die  manufacturing  unit  of  the 
plastics  unit,  Erie  Resistor  Corp.,  Erie,  Pa. 

*  *     * 

As  a  part  of  the  company's  sales  expansion  program,  Advance 
Pressure  Castings,  Inc.,  Brooklyn,  N.  Y.,  has  appointed  Philip 
G.  Nase  as  its  representative  in  the  New  Jersey  territory. 

*  *     * 

Dr.  Jan  Teppema  has  joined  International  Plastic  Corp., 
Morristown,  N.  J.,  as  director  of  laboratory  operations. 

*  *        * 

Harry  H.  Purvis  has  been  appointed  general  manager  of  the 
new  Lnmite  plant  of  Chicopee  Mfg.  Corp.  at  Cornelia,  Ga. 

*  *    * 

Recent  personnel  appointments  in  the  General  Electric  Co.'s 
Plastics  Divisions  include  those  of  David  FitzGerald  to  man- 
ager of  employee  relations,  and  Guy  M.  Stone,  manager  of  the 
Coshocton  plant. 


D.  FitzGerald 


G.  M.  Stone 


I.  D.  Patterson 


Ian  D.  Patterson  has  been  appointed  to  the  newly-created 
position  of  assistant  manager  of  Goodyear  Tire  &  Rubber  Co.'s 
chemical  product  development  division,  which  includes  among 
its  current  activities  development  of  plastics  flooring,  plastics 
films,  and  special  purpose  resins. 

*  *        * 

Announcement  has  been  received  that  Capt.  Mark  E.  Sink 
has  joined  the  industrial  designing  organization  of  Peter  Miiller- 
Munk,  Pittsburgh,  where  he  will  be  responsible  for  research, 
servicing  and  production  and  will  act  as  Mr.  Miiller-Munk's 
assistant. 

*  *    * 

Walter  E.  Gloor  has  been  appointed  to  head  a  new  products 
development  section  of  Hercules  Powder  Co.'s  cellulose  products 
department  in  Wilmington,  Del.;  Courtland  K.  White  has 
succeeded  Mr.  Gloor  as  plastics  supervisor  of  the  company's 
Parlin,  N.  J.,  plant. 

*  *    * 

Alfred  W.  Long,  treasurer  and  director,  Shawinigian  Resins 
Corp.,  Springfield,  Mass.,  was  recently  elected  president  of  the 
Springfield  chapter,  National  Association  of  Cost  Accountants. 

*  *        * 

Dr.  Edmund  S.  Rittner  has  joined  the  research  staff  of 
Philips  Laboratories,  Inc.,  as  associate  chemist. 

*  *    * 

Justin  J.  Wetzler  has  been  appointed  director  of  engineer- 
ing and  J.  Harvey  Chandler,  chief  engineer,  of  Barnes  & 
Reinecke,  Chicago. 

*  *        * 

John  W.  Porter  has  recently  resigned  from  the  presidency 
of  Alabama  By-Products  Corp.;  he  is  succeeded  by  Phil  H. 
Neal. 

*  *        * 

John  H.  Beach  has  been  appointed  sales  representative  in  the 
N.  Y.  State  area,  and  Donald  M.  Gawthrop  in  the  Philadel- 


The  story  of  timber  in  the  Pacific  Northwest  is 
dramatic  and  well  known.  The  story  of  timber  and 
the  wood  plastics  industry  is  new . . .  and  vital! 

A  BACKLOG  OF  12  BILLION  FEET  OF  "PLASTIC 

TYPE"  TIMBER  IS  AVAILABLE  AT 

GRAYS  HARBOR  NOW! 

Think  of  the  tremendous  operational  advantages  of 
a  plant  located  in  the  GRAYS  HARBOR  area  in 
Washington  ...  a  surplus  of  raw  material  for  manu- 
facturing ...  a  huge  supply  of  industrial  water  .  .  . 
cheap  electric  power  .  .  .  efficient,  dependable  labor 
.  .  .  low  cost  transportation  by  land,  air  and  sea! 

Investigate  GRAYS  HARBOR  industrial  sites  for 
the  plastics  industry.  Detailed  information  pertinent 
to  your  specific  problems  is  available.  Well-financed 
civic  organizations  such  as  Grays  Harbor  Industries, 
Inc.,  are  eager  to  cooperate  with  outside  capital  and 
management.  Write  to  the  address  below  for  infor- 
mation ...  or,  if  you  prefer,  a  personal  representative 
will  call  on  you. 


GRflVS  HflRBOR 


Sponsored  By 

GRAYS  HARBOR  INDUSTRIES,  INC. 

ABERDEEN,  WASHINGTON 


AUGUST  1946 


PLASTtCS 


87 


AQUA  PLASTIC  DYES 


NEW  WATER-SOLUBLE 
DYES  FOR  CLEAR    PLASTICS 

Av*'ikbl*     in     It    b*»<«    *ol«r«    from    which   ISO 
«ompi«l»iy    Uu*    »*•**•  m*jr    b*  ootistnod,    Thi» 
•  •tfcosl    «*n     bo     u  • » <j     by    the     f  »br  ic^tor     or 
n«r    bofor*    or    **t*'     protecting.      ln*ap*n- 

•Olution:  l>mply  dip— (inM  wit*  w.«l*f 
OMl'i  mil  —  No  o«pon*.v«  *o,uipmont  of 
•rtoMl  choimicAl*  to  buy. 

AmoM  lh«  othor  ••collont  product*  from 
Owr  UbOTAton**  *r*  Annt>*l>ng  Compound 
i Ac*  y  I  ic  C«mont>.  L^m  mating  t>y*»  (Col  - 
orod  C*n*on().  Now  tonution*!  "GAM- 
CO"  BuHtog  Compot*"d — will  not  burn, 

Phone  FEderal  1109 


GR1AT  AMERICAN 
COLOR    COMPANY 

2512  WEST  NINTH  STREET 


LOS  AHftlLH.  CAUf. 


Conodtan  ftoo<   Colon  &  Fioithos  Co.,   222   Front  »fr*«r,  Edit  Toronto,  Ontario 
Now  Tort  >op;    Ploitki    Dyo    &    Supply    Co.,  Qcoon  Goto,  Now  Joftoy 

a  comp/.f  o  /.'M  •/  Cold  lip  Wy.. 


SENSATIONAL  PROFITS  FOR 
PLASTICS  FABRICATORS! 


*  Mere's  an  item  with  cash  appeal  ...  a  sparkling  modern  metal  and 
plastic  cigarette  case  which  rou  can  turn  out  in  your  shop  for  as  low  as 
68c  each,  complete.  The  identical  cigarette  case  it  selling  at  better  stores 
lot  »2.95. 

*  We  rapplr  the  metal  stampings  .  .  .  You.  the  plastics  fabricator,  make 
the  simple  plaitic  cover,  attaching  it  to  the  metal  stamping  by  bending  the 
foor  prongs.  The  total  operation  costs  about  1  9c. 

*  These  are  the  prices  which  permit  you  such  a  wide  margin  of  profit: 


Oin 


$4.00    p»r   rf«i*nj    163  00    awr 
*  n«>.    $I.SO  p.f   d...n,   JtS.OO 


\trcif,  Ihf  lilt  <r**ttJ:  M  h»U  13  ciunltti;  *  h»U  11  f,  until,,  filktr 
*u  ttUt  Su»J*nl  or  Hint  tilt. 

I'Uit  xwr  tnltr  •««  .  V  r  i**mtn  I  fit,  nli*Ht  unxi. 


BELLCO  PLASTICS,  INC. 

'  147  W.  Sidney  Axe..  Mount  Vernon.  N.  Y. 


phia-Baltimore    area,    for    Northern    Industrial 
South  Boston.     John  K.  Boosahda  is  to  be  sales 
the  Boston  area. 


Taber  Instrument  Corp.,  No.  Tonawanda.  N.  Y.  has  an- 
nounced the  appointment  of  Arthur  P.  Schulze  as  public  rela- 
tions director. 

*  *        * 

G.  F.  D'Alelio  was  recently  named  manager  of  high  polymer 
research  for  Industrial  Rayon  Corp.,  Cleveland. 

*  »        * 

Joseph  H.  Ward,  executive  vice  president  of  Noma  Electric 
Corp.,  N.  V.,  has  been  assigned  new  responsibilities  as  sales 
director  and  supervisory  officer  for  six  divisions  and  ten  subsidi- 
aries of  the  company  in  the  toy,  decorative  lighting  and  allied, 
fields,  including  the  plastics  and  capacitor  divisions. 

*  *        * 

Dr.  Sidney  M.  Cadwell  has  lately  been  appointed  director 
of  research  anil  technical  development  of  United  States  Rubber 
Co.  His  experience  with  the  company  covers  extensive  work  in 
the  administrative  and  scientific  phases  of  the  fields  of  rubber 
and  plastics. 


I.  H.  Ward 


Dr.  S.  M.  Cadwell 


M.  Spain,  Jr. 


Recently  announced  by  Walter  J.  A.  Connor,  vice  president 
and  director  of  sales,  Chemaco  Corp.,  is  the  appointment  of 
Maurice  Spain,  Jr.,  as  the  company's  New  England  sales 
representative. 

*  *        * 

Ken  Hagen  has  assumed  his  new  duties  as  head  of  the  plastir- 
division.  U.  O.  Colson  Co.,  Paris,  111.;  he  was  formerly  with 
Precision  Plastics  Co.,  St.  Louis. 

*  *        * 

N.  H.  Critton  has  been  made  eastern  sales  manager  of  Mon- 
arch Machine  Tool  Co.,  and  will  headquarter  in  X.  Y.,  where 
he  will  also  have  supervision  of  the  company's  export  sales  staff. 
F.  J.  Griffis  succeeds  Mr.  Critton  as  Monarch's  district  man- 
ager in  Newark,  N.  J. 

*  *        * 

Following  recent  reorganization  of  Pennsylvania  Salt  Co.'s 
manufacturing  department  because  of  increased  volume  and  new 
products.  Walter  Penfield  has  been  made  manager  of  manufac- 
turing ;  Claude  S.  Beldin  has  become  production  manager,  a 
newly  created  position,  and  Henry  G.  Meyer,  assistant  to  the 
production  manager.  Sydney  L.  W.  Lea  h.-i^  txvonie  advorti-- 
ing  manager. 

*  *        » 

Edwin  M.  Allen  has  recently  retired  from  liis  |»>st  as  chair- 
man of  the  board  of  The  Mathieson  Alkali  Works,  but  will  con- 
tinue as  a  director  of  the  company,  according  to  announcement 
by  George  W.  Dolan.  president. 

*  *        • 

Harry  K.  Collins  has  been  appointed  manager  of  the  r.-in 
and  insulation  materials  division  of  General  I  lectric  Co.,  Pitts- 
field,  Mass.,  succeeding  the  late  Edgar  L.  Feininger.  John  C. 
Morris  has  been  named  superintendent  of  manufacturing  for  the 

division. 

*  *        * 

American  Foundry  Equipment  Co.,  Mishawak.i,  Ind.  hai 
announced  administrative  |>er><mnel  apiKiintinenls  as  follows: 
Kenneth  H.  Barnes,  eliief  engineer:  Chalmer  R.  Cline,  engi- 
neering assistant  to  the  president;  and  Sherrill  S.  Deputy. 
assistant  -air-  manager. 

*  •        * 

Ralph  E.  Thompson  has  recently  been  elected  to  fill  a 
vacancy  on  the  hoard  of  directors  of  National  Research  C  «rp  . 
Boston. 


PI.ASTH ''S 


AUGUST  1946 


" 


ROBLEMS  in 


plastics 


Problems  and  questions  may  be  submitted 
to  this  department  for  answering  by  the  tech- 
nical editors  or  specialists  in  the  industry. 

We  are  trying  to  chose  a  plastics  material  for  a  molded  product 
which  will  be  used  in  chemical  laboratories  and  plants,  and  wish 
to  know  as  much  as  possible  about  the  resistance  of  urea  formal- 
dehyde and  melamine  formaldehyde  to  various  chemicals. 

F.  F.,  Farmingdale,  N.  Y. 

Urea  formaldehyde  is  decomposed  by  strong  acids  and 
alkalies.  It  is  not  affected  by  common  solvents,  greases, 
oils,  hydrocarbon  solvents,  and  weak  alkalies.  Some 
authorities  say  it  is  not  affected  by  iveak  acids,  whereas 
others  ^vill  warn  against  letting  it  come  in  contact  with 
them. 

Melamine  formaldehyde  is  also  decomposed  by  strong 
acids.  It  is  not  affected  by  weak  acids  and  alkalies, 
water,  or  organic  solvents.  Certain  grades  are  inert  to 
strong  alkalies. 


We  need  a  transparent  material  similar  to  the  acrylics,  but 
which  is  somewhat  lighter  and  possesses  greater  surface  hard- 
ness. Can  you  tell  us  whether  there  is  such  a  plastics  material? 

B.  U.,  New  York,  N.  Y. 

Polystyrene  has  a  lower  specific  gravity,  is  trans- 
parent, and  is  generally  thought  to  have  a  harder  surface 
than  the  acrylics.  However,  grades  of  acrylics  with  im- 
proved surface  hardness  have  recently  been  developed  or 
are  in  the  laboratory  or  pilot  plant  stage,  and  it  is  con- 
ceivable that  some  of  these  new  formulations  may  be 
superior  to  polystyrene  in  this  property. 

*  *        * 

What  can  be  done  to  increase  the  cigarette-burn  resistance  of 
laminated  sheets  to  be  used  as  table  and  counter  tops? 

L.  Z.  S.,  Los  Angeles,  Calif. 

The  common  practice  is  to  include  under  the  surface 
laminate  a  thin  sheet  of  aluminum  foil  which,  by  conduct- 
ing the  heat  away  and  dissipating  it  over  an  increased 
area,  prevents  a  damaging  localized  rise  in  temperature. 

*  *        * 

We  are  interested  in  obtaining  laminated  sheets  made  with 
thermoplastic  resins.  Can  you  tell  us  whom  to  contact? 

E.  S.  J.,  Seattle,  Wash. 

The  process  of  laminating  thermoplastic  resins  is  still 
a  very  new  one.  For  information,  ive  suggest  you  get  in 
touch  with  Mr.  R.  J.  Metsler  of  the  Hercules  Powder 
Company,  Wilmington  99,  Delaware,  zvho  has  been  do- 
ing experimental  work  along  this  line. 

*  *        * 

What  are  the  methods  used  in  performing  a  three-color  print- 
ing job  on  clear  vinyl  film?  H.  J.,  Minneapolis,  Minn. 

Rotary  press  and  aniline  ink,  offset  press,  letterpress, 
and  silk  screening  are  among  the  various  methods  used. 


(plci&JtjucA. 


Expressly  designed  for 
granulating  the  various 
types  of  plastic  materials 

Advanced  design  features  enable 
Cumberland  machines  to  perform  at 
maximum  efficiency  the  special  cut- 
ting required  by  plastics  materials. 
Machines  are  made  in  two  styles: 
smaller  machines.  No.  0,  No.  Mz  and 
No.  IVi  as  at  right  (No.  ¥2  illus- 
trated). Style  of  large  machines  as  at 
left  with  retractable 
knife  block  for  maxi- 
mum accessibility  (18" 
Machine  illustrated). 

Request  illustrated 
CATALOG  NO.  200 

CUMBERLAND  ENGINEERING  CO. 

Dept.  B — Box  216,  Providence,  R.  I. 


AUGUST  1946 


PLASTICS 


89 


AT'S 


PLASTICS 


New  Water-Repellent  Material 

General  Electric  Company.  Chemical  Depl. 
1  Plenties  Are..  Pitufield.  Mass. 

Faster  starting  of  flourescent  lamps  by  the  application  of  Dri- 
f-'ilm  is  now  being  accomplished.  This  new  water-repellent  mate- 
rial forms  an  invisible  and  permanent  coating  over  the  lamp,  and 
is  said  to  be  the  best  material  yet  found  to  form  a  continuous 
insulating  film  over  the  glass.  Lamps  coated  with  Dri-Film 
operate  satisfactorily  even  under  100%  relative  humidity.. .  (555) 


Rotating  Pan-Type  Mixer 

Ransome  Machinery  Company 
1519  S.  Second  St.  Dunellen.  N.  I. 

New  rotating  pan-type  mixers 
available  in  sizes  up  to  2500  Ib 
(50  cu  ft)  batch  capacity  have 
been  developed  for  a  variety  of 
ii-e-  in  industries  which  require 
mixing,  blending,  tumbling,  pol- 
ishing, finishing,  and  similar  op- 
entkuM. 

Although  the  rotating  pan  i- 
motor-tilted  and  motor-rotated 
at  constant  speed,  a  variable 
s|>eed  drive  can  be  furnished 
where  materials  handled  require 
the  rotating  speed  to  vary.  To  assure  thoroughly  mixed  uniform 
hatches,  mixing  blades  are  added  as  necessary  in  mixing  or  blend- 
ing two  or  more  ingredients (556) 


Electronic  Seamer 

Union  Special  Machine  Co. 
415  N.  Franklin  St..  Chicago.  111. 

A  new  unit,  developed  by  a  manufacturer  of  industrial  sewing 
machine*.  for  the  do  ironic  seaming  of  thermoplastic  film  mate- 
rials, is  equipped  with  an  RCA  200  meg  constant  frequency 
power  generator  and  has  sufficient  power  to  seal  10  thicknesses 
of  .004"  vinyl  film  or  two  thicknesses  of  .020"  film.  Power  is 
taken  from  any  ordinary  110-120  v,  single  phase,  60  cycle  A.C. 
line  capable  of  supplying  13  amp,  and  is  supplied  to  rotary  type 
electrodes  at  seaming  head.  Seam  widths  ranging  from  1/16" 
to  %"  may  be  obtained  by  changing  the  top  electrode.  A  dis- 
tinctive feature  of  this  machine  is  its  ability  to  produce  the  fused 
seam  in  a  silent  continuous  operation (557) 


Plastics  Folding  Machine 

Tober  Instrument  Corp..  Plastics  Eqpt.  Div. 
Ill  P  Goundry  St..  North  Tonawanda.  N.  Y. 

Representing  a  new  achievement  in  the  field  of  sheet  plastics 
fabrication,  the  Thermofold  folds  plastics  sheeting  ranging  from 
.005"  to  .020"  in  thickness,  into  a  "U"  type-180°-fold,  with  sides 
tight  together 

By  actually  molding  the  material  into  the  desired  fold,  com- 
mon faults  of  a  crease  or  bend — such  as  tearing,  cracking,  or 


U  rapidly-moving  timel  tuch  al  thai*,  kaapinq  up 
•  !th  iv«ry  Utett  development  in  ona'i  field  it  a 
"mu«»."  In  order  to  limplify  for  our  reederi  the  tetl 
of  obtaining  detailed  Information  regarding  tha  new 
product!,  procatiet  and  !r«d«  literature  detcrlbed 
herein,  •leiflci  hai  keyed  eech  item  in  thit  lection 
with  a  number,  end  he»  provided  the  name  end  ad- 
drew  of  the  manufacturer  or  producer  of  each. 

Mention  of  the  key  number,  esd  of  (he  iuee  of 
p/eif/ci  In  which  the  newt  item  appeared,  will  terve 
ei  quick  identification  of  the  product  when  wrltlne, 
the  individual  manufacturer  or  producer  for  further 
d.t.ilt 


opening  up — are  eliminated.  The  machine  is  operated  with  ther- 
mostatically-controlled heat,  and  is  reported  to  be  fully 
able  to  accommodate  all  types  of  thermoplastic  sheeting,  and 
size  and  thickness  of  fold.  The  unit  is  hand  fed,  foot  oprr.ited, 
and  provide-  an  automatically-controlled  folding  cycle  Operat- 
ing accessories  include  an  electric  switch;  two  indicator  lights, 
one  to  designate  when  electrical  current  is  operating,  the  other 
to  indicate  functioning  of  the  thermostatic  heat  control:  a  dial- 
type  thermometer  to  show  temperature  of  the  heated  folding 
blade  of  16"  capacity;  and  adjustable  thermostat  to  regulate 
folding  blade  temperature. 

Completely  enclosed  but  readily  accessible  through  hinged  end 
doors,  the  machine  requires  little  or  no  servicing  because 
prelubricated  ballbearings  and  oilless  bushings 


Short  Run  Injection  Press 

Munton  Manufacturing  Company 
9400  Belmont  Ave.,  Franklin  Park.  111. 

Developed  for  use  in  tests  and  samples  to  prove  color  and 
molds,  and  for  short  runs,  the  Plastic  Injection  Molding 
Machine  is  said  to  augment  larger,  more  expensive  machinery. 

A  large  capacity  hopper,  heat  control,  automatic  cut-off, 
hydraulic  ram  and  foot-power  unit,  plus  a  counterbalanced  open- 
close  lever  and  a  toggle  lock  which  holds  molds  securely,  are 
standard  equipment  on  this  3-oz  foot-operated  press. 

Upper  and  lower  molds  are  placed  between  plates,  secured, 
adjusted,  and  lever-closed.  Plastics  fed  from  the  hopper  till-  the 
heating  tube.  When  desired  degree  of  heat  is  reached.  <'i 
fills  mold  with  the  plastics  by  pumping  the  treadle  of  the  foot 
power  unit.  While  plastics  is  being  heated  for  the  next  operation. 
operator  pulls  back  lever,  opening  mold  and  automatically  shut- 
ting off  heat.  The  finished  product  is  removed,  and  mold  prepared 
for  its  next  job (559) 

Self-Contained  Platen  Press 

R.  D.  Wood  Co 

Public  Ledger  Bldg,,  Philadelphia,  Pa. 

By  setting  the  automatic 
pressure   controller   at   re- 
quired pressure,  this  50-ton 
self-contained  platen   press 
can    be    operated    at    pres- 
Mires  ranging  from  1000  psi 
to  .HXKI  psi.    IV 
by  push  button  control. 
The   pump   is   automati- 

J^_  —    Jfk_^m  cally  stopped  during  opera- 

•';•.  H^^E^.  ''""     wlu'"     Predetermined 

r  B^  pressure  has  been  reached. 

'  "  "XOU'i  During   curing   period, 

^*^l  should    pressure   drop   2% 

to  2%%,  pump  automati- 
cally starts  to  rebuild  the 
required  pressure.  At  the 
termination  of  the  curing  period,  pressure  is  released  from  the 
cylinder  and  press  opens  by  operating  the  release  valve. 

Suited  to  laboratory  and  general  service,  the  15"  X  15"  X  2" 
platens  arc  machined  parallel  within  .003"  and  provided  with  a 
smooth  tool  finish.  The  intermediate  heating  platen  is  sus- 
pended by  steel  hanger  rods  and  guided  on  the  columns  by 
means  of  cast  iron  guide  brackets (560) 

New  Scribing  Plate 

Eastman  Kodak  Company 
Rochester  4.  New  York 

The  Kodak  Green  Scribing  Plate,  a  new  engineering  material 
developed  for  u»e  with  optical  comparators  of  the  contour  pro 
jection  type,  consists  of  a  transparent  green-dyed  gelatin  coating 
applied  to  glass.  Tolerance  lines  are  scribed  on  the  plate  by 
cutting  through  the  gelatin  film. 


p LAST H  s 


AIM  ST    19  IK 


These  plates  may  be  used  directly  with  the  contour  compar- 
ators' as  printing  masters  for  photographically  duplicating  the 
contour  comparator  plate ;  and  for  making  small  photo  templates 
on  metals,  plastics,  and  other  materials. 

Said  to  offer  an  easy,  fast  and  safe  method  of  manufacture, 
the  new  Kodak  product  also  permits  easier  and  more  accurate 

..  ( bol) 

reading 

For  Checking  Surface  Finishes 

The  Brush  Development  Company 
3405  Perkins  Ave.,  Cleveland  14,  Ohio 

The  new  Model  BL- 

knflMBMMj  HMH      W3  Surface  Analyzer 

is  reported  to  give 
added  accuracy  to 
modern  industrial  in- 
spection by  making 
possible  accurate  sur- 
face analysis  of  metals, 
plastics,  paper  and 
other  materials  in  the 
laboratory,  early  in  the 
production  line,  or  in  final  surface  checking. 

Surface  finishes  from  less  than  1  to  5000  microinches  can  be 
checked.  Accurate  "peak  and  valley"  profile  of  surface  finish  is 
provided  by  instantaneous  chart  record  on  the  magnetic  direct- 
inking  oscillograph.  Where  "peak  and  valley"  profiles  are  not 
needed,  the  Brush  RMS  meter  provides  a  constant  visual  check 
of  RMS  surface  roughness (562) 


Small  Hole  Gage 

Federal  Products  Corp. 

1144  Eddy  St..  Providence,  R.  I. 

A  new  dial  indicator  gage,  Model  1203  P-l,  which  will  gage 
holes  within  a  range  of  .122"  up  to  .250",  by  means  of  a  set  of 
12  interchangeable  gaging  plugs,  has  lately  been  introduced  to 
the  market  by  this  company.  It  is  described  as  providing  rapid, 
precise  dimensional  measurement,  and  to  be  capable  of  a  measur- 
ing range  formerly  beyond  the  scope  of  a  dial  indicator. 

This  gage  is  calibrated  and  set  for  any  specified  i.d.  to  reveal 
the  condition  of  holes  up  to  a  total  range  of  plus  or  minus  .004". 
The  minimum  graduation  is  .0001".  Dial  is  balanced  and  can  be 
rotated. 

Regularly  furnished  for  use  as  a  single-purpose  gage,  addi- 
tional plug  sizes  are  obtained  by  the  use  of  a  micrometer  caliper, 
which  will  easily  adapt  and  calibrate  such  plugs  to  the  instrument. 

Said  to  be  exceptionally  accurate  and  extremely  sensitive  to 
very  fine  dimensional  variations,  this  compact  and  precise  gage 
is  well  built  and  does  not  require  skilled  manipulation,  according 
to  its  makers.  Two  extra  springs  and  a  wrench  are  part  of  the 
set (563) 


Oven  for  Preheating 

Despatch  Oven  Co. 

619  S.E.  Eighth  St..  Minneapolis  14,  Minn. 

The  PLHD-2-5 
oven,  designed  to 
eliminate  failures 
and  irregularities 
in  extruded  stock 
caused  by  im- 
properly pre- 
heated granules, 
is  automatically 
controlled  to  pro- 
vide balanced 
temperature  and 
heat  flow  in  all 
its  10  drawers, 
each  drawer 
measuring  20"  by 
30"  by  y/2".  A 
special  high  velocity  fan  provides  forced  draft  horizontal  air 
flow ;  and  3"  of  insulation  assure  minimum  heat  loss  through 
the  walls  of  the  oven. 

These  ovens  are  available  in  many  different  capacities  to  meet 
all  preheating  and  curing  requirements.  They  are  arranged  with 
electric  heating  systems  for  110  v  or  220  v  current (564) 


You're  Assured  of 

DEPENDABLE 

Heavy  Duty  Compression 

MOLDS 

with 

AJAX  6F  STEEL 


HERE'S  WHY! 

AJAX  "61"  is 


•   ELECTRIC   FURNACE    QUALITY 


•   EASILY   MACHINED 


•   FREE   OF   FLAKES,  CRACKS 
and    STRINGERS 


Ajax  "61"  Steel  in  Ajax  forged  mold  blanks  means 
real  economy  in  compression  molds  specified  for 
heavy  duty.  Ajax  Steel  is  hardened  to  your  [ob  speci- 
fication and  is  guaranteed  free  of  defects  in  material 
and  workmanship.  Ajax  is  proud  of  its  record  and 
reputation  among  plastic  molders  for  trouble-free, 
high  quality  mold  steel. 

We  invite  you  to  bring  your  mold  steel  problems  to 
AJAX  Steel  and  Forge  Company. 

Valuable  tf-iee.  Booklet 


Wrte  our  Service  Department  for 
your  copy  of  the  famous  "AJAX 
BLACK  BOOK."  Full  of  useful  in- 
formation, steel  weights,  standard 
specifications,  conversion  tables, 
etc. 


AUGUST  1946 


PLASTICS 


91 


WE  are  now  granting  license 
and  furnishing  equipment  for 
making  this  sensational  new 
folded  plastic  box. 

Protection,  reuse  and  display 
combine  in  these  rigid  boxes 
that  are  made  from  cellulose 
acetate  or  vinylite  and  which 
require  no  cement  or  solvent 
to  hold  them  together. 

THE  BOX  THAT'S  NEVER  THROWN  AWAY 

ION  \    II     OXLEY  CO. 

Miiiinliirl  iir«T   A    Hf«ii;iiiT 
\\   \  I  I  H  I  <M\  \  >I\*S\<  III  SKTT* 


Literature  Review 

Saran  Coating  Materials 

The  Dow  Chemical  Company 
Midland,  Michigan 

Technical  data  booklets  are  available  from  the  manufacturer 
of  two  new  coating  materials— Saran  F-120,  a  solvent  soluble 
resin  which  imparts  very  low  moisture  vapor  transmission ;  and 
Saran  I--122.  a  latex  forming  a  continuous  film  upon  air  dry- 
ln*  (565) 

Decals  as  Advertising  Media 

The  Meyercord  Company 

5323  W.  Lake  St..  Chicago  44.  111. 

Issued  as  a  guide  to  point-of-sale  promotion  and  containinj 
suggestions  for  dealer  identification  and  product  promotion,  tht 
"Decalcomania  Sign  Ad- Visor"  discusses  how  to  use  decal  sigru 
to  best  advantage,  and  describes  how  store  and  window  decalj 
stimulate  buying. 

The  brochure,  which  reproduces  94  colorful  decal  signs  used 
by  leading  advertisers,  is  said  to  be  the  most  comprehen- 
its  kind  ever  released  by  the  company 

Chemicals  and  Explosives 

Hercules  Powder  Company 
Wilmington,  Delaware 

In  a  new  attractive  booklet  designed  for  easy  reference,  Her- 
cules chemicals  and  industrial  explosives  are  indexed  first  ac- 
cording to  the  many  industries  in  which  they  are  used,  and  then 
broken  down  according  to  chemical  families. 

Among  the  chemicals  which  are  discussed  and  for  which  ap 

plications  are  suggested  are  the  cellulose  family,  rosin  family, 

,  synthetic  resins  and  chlorinated  products (567) 


BENZOYI 


ROXIDE 


Metals  and  Alloys 

Weslinghouse  Electric  Corp. 

306  Fourth  Ave..  Pittsburgh  30,  Pa. 

A  guide  to  the  properties  and  applications  of  18  recent  metal- 
lurgical developments  is  presented  in  a  new  48-page  illustrated 
booklet,  B-3369.  Physical  and  electrical  characteristics  of  thes« 
new  metals  and  alloys  as  compared  with  other  commonly  used 
materials,  are  listed  in  a  2-page  table.  Sketches,  diagrams, 
curves  and  tables  throughout  the  booklet  present  detailed 
data  (568) 


Impregnating  Resin 

Furane  Plastics  and  Chemicals  Co. 
4500  Brazil  St..  Los  Angeles  26.  Calil. 

A  description  of  Plasprtg,  plastics  resin  used  for  impregnation 
of  plaster  of  Paris,  and  a  listing  of  its  industrial  and  decorative 
applications,  is  contained  in  a  new  folder  issued  by  the  manu- 
facturer  ( 5(,g) 


Mutual  Solvents 

Armour  Chemical  Division 

1355  W.  31st  St.,  Chicago  9.   111. 

A  new  technical  bulletin  titled  "The  Armids  as  Mutual  Sol- 
vents for  Waxes  and  Plastics"  describes  the  use  of  commercial 
octadecanamide  in  blending  certain  plastics  with  paraffin  and 
microcrystalline  waxes.  Resultant  o  mil*  muds  vary  from  soil, 
wax-like  materials  to  hard,  flinty  suri.uvs,  ile|>eti(liiiR  on  the  for- 
mulations used.  Phase  diagrams  showing  areas  of  compatal>ility 
are  included  in  the  bulletin ( 570) 


Electronic  Interval  Tinier 

Electronic  Controls,  Inc. 

44  Summer  Ave..  Newark  4.  N.  ). 

The  new  Model  1029  electronic  interval  timer,  described  in  a 
•!y  released  bulletin,  is  recommended  by  its  manufacturer 
for  all  industrial  applications  requiring  highly  accurate  circuit 
timing.  With  a  time  range  of  0  to  2  min  in  1  sec  steps,  it  has  an 
accuracy  of  Ixrtter  than  5%.  Contacts  are  rated  at  500  watts  at 
voltages  to  32  v  DC  and  125  v  AC (571) 


1'I.ASTil-S 


1946 


r 


German  Plastics 

(Continued  from  page  38) 


raw  natural  products.  Their  production  of  fibers  included 
some  outstanding  achievements.  In  the  field  of  paste  appli- 
cations, they  appeared  to  be  far  ahead  of  United  States 
practices.  Developments  along  the  lines  of  plastics  foams 
were  well  advanced  and  appeared  to  be  at  least  on  a  par 
with  those  of  the  United  States. 

We  in  the  United  States  would  do  well  to  review  the 
German  work  in  the  field  of  plastics  very  carefully.  A  com- 
bination of  the  German  art  with  the  well-established  United 
States  art  will  do  much  to  advance  the  whole  plastics  in- 
dustry. The  question  of  patents  relating  to  these  various 
fabrication  processes  outlined  is  not  yet  clear,  but  should 
not  be  overlooked.  END 


Costume  Accessories 

(Continued  from  page  59) 


acetates,  thus  transforming  the  most  prosaic  daytime  frock 
into  more  gala  attire. 

In  the  dressier  type  of  belts  and  dress-girdles,  a  simple 
afternoon  frock  of  wine  red  material  can  be  visualized 
accented  by  a  belt  of  the  same  fabric  studded  with  "rubies" 
— made  of  injection  molded  polystyrene.  Or  a  simple  white 
flowing  Grecian  evening  gown,  with  a  midriff  girdle  of  gold 
leather  set  with  "topaz"  and  "emeralds"  molded  of  the  same 
plastics  material. 

Metal  plating  over  cellulose  acetate  also  has  its  distinc- 
tive use  for  belt  ornamentation  and  findings,  such  as  slides 
and  buckles.  Golden  eyelets  on  a  staid  leather  belt  will  lift 
it  from  the  ordinary  to  an  item  of  elegance. 

One  of  the  smartest  novelty  applications  of  plastics  in  the 
belt  field  is  a  vinyl-impregnated  handwoven  genuine  wood 
veneer,  ideal  for  use  with  sports  clothes.  This  material  is 
best  combined  with  leather.  END 


^, 


Glboming,  injection  molded  plastics  cabochons  also  deco- 
rate smart  handbag,  form  jewel-like  units  of  modish  belt 


OPEN 

TIME 

AVAILABLE 


and 


PLASTIC    MOLDS 

PLASTIC  SERVICE  ENGINEERING 

2567  WEST  GRAND  BLVD. 
DETROIT  8,  MICH.  DEPT.  21  Tyler  7-2055 


A  flat  iron  handle  for  Landers,  Frary  &  Clark — molded  in 
black  Bakelite  by  the  oldest  molder  of  plastics  in  America. 
Custom  Molding  parts  for  electrical  appliances  and  equip- 
ment has  been  a  specialty  with  Waterbury  Companies,  Inc., 
for  many  years. 

WATERBURY  COMPANIES.  INC. 

Formerly  Waterbury  Button  Co.,  Est.   1812 
Dept.  S,  Waterbury,  Connecticut 


AUGUST    1946 


PLASTICS 


93 


if,  / 


error 


w. 


itize  In  the  hard 


Specialize  in 
chromium  pfatinp  of  plastic 
moulds  ana.  dits  /• 
finish. 


a  mrror 


CHROME  SERVICE 


Save  It  with  Chromium 

9350  GRINNELL  AVE.      •      DETROIT   13,  MICH. 
Plaza  3164 

1926         Oar  20th  Year  of  Dependable  Service          1946 


L.  H.  BATTALEN 

DESIGN.   MECH.  ENG. 

MOtELS  —  HOBS  —  MOLDS 

TOOL     AND     DIE     MAKING 

247   Wyckoff  St.  Brooklyn.   N.   Y.  Mai*   5-1129 


ROUTER  BITS— FORM  CUTTERS  and 
MACHINES  for  HIGH  SPEED  CON- 
TOUR and  STRAIGHT  CUTTING  PLASTICS 

Stn4  lor  Ctltlof  No.  4} 

EKSTROM,  CARLSON  &  CO. 

1410   Railroad   AT».  BOCXFORD,  nt 


FARNSWORTH  ENGINEERING  INC. 

356  BROAD  STREET  FITCHBURG,  MASS. 


Oi  $10  Nit  5 


INJECTION  MOLDS 


Mill  DC  US 


ANDREW    C.    KARLSTAD 

INDUSTRIAL  DESIGNER 

COMPLETE    PRODUCT    DESIGN   .   ENGINEERING    SERVICE 


«i«  VENTURA  CANYON  AVE. 

PHONE-STATE  444W 


SHERMAN  OAKS.  CALIF 
(A  SUIURI  OF  LOS  ANGELES) 


overseas 


The  British  plastics  industry  is  currently  passing  through  a 
major  basic  raw  materials  crisis.  Oil  production  from  wells  lo- 
cated in  the  United  Kingdom,  which  accounted  for  404,617  tons 
from  1939  to  1945,  has  dropped  to  a  trickle  of  a  mere  few  thou- 
sand tons.  The  output  of  coal  (about  the  only  plastics  raw 
material  in  which  Britain  is  really  self-sufficient)  is  officially 
estimated  to  have  declined  by  20,000,000  tons  annually  since 
1'Ml,  and  continues  to  drop.  Wood  flour  has  been  in  critical 
short  supply  for  some  time,  due  to  a  hold-up  in  importations 
from  Sweden,  Norway,  Finland,  Canada  and  other  timber- 
producing  countries. 

In  fact,  the  acute  scarcity  of  basic  raw  materials  has  already 
resulted  in  drastic  reductions  in  the  manufacture  of  an  entire 
range  of  urgently  needed  plastics  commodities. 

Despite  the  difficult  situation  in  raw  materials,  however,  the 
British  plastics  industry  appears  determined  to  build  up  capacity 
markets  for  home  and  export.  • 

A  number  of  manufacturers,  particularly  those  in  the  plastics 
molding  group,  are  already  engaged  in  extending  research  labo- 
ratories, improving  existing  manufacturing  plants,  gearing  up 
production  capacity  and  generally  equipping  themselves  commer- 
cially, as  well  as  technically,  to  handle  increased  volume  of 
products. 

For  example.  Britain's  largest  chemical  and  plastics  manu- 
facturing concern.  Imperial  Chemical  Industries  Ltd..  recently 
announced  a  long-term  expansion  program  involving  a  capital 
expenditure  of  $80,000,000  within  the  next  eight  years. 

According  to  Lord  McGowan,  chairman  of  I.C.I.,  the  virtual 
elimination  of  German  and  Japanese  chemicals  and  plastics  is 
causing  increasing  numbers  of  former  customers  of  those  coun- 
tries to  look  to  Britain  for  supplies,  and  in  order  to  meet  their 
demands  and  gain  new  markets  overseas,  the  British  plastics  in- 
dustry as  a  whole  must  pursue  a  vigorous  expansion  program. 

Plastics  in  Boats  and  Cars 

A  British  company,  Fairey  Aviation  Ltd.,  has  started  produc- 
tion of  all-plastics  sailboats  made  of  welded  plastics-plywood 
"skins."  12  ft  long,  they  are  rigged  with  a  self-swivelling 
plastics-alloy  mast. 

Testimony  to  the  speed  and  ease  of  handling  of  this  boat  is 
the  fact  that  its  prototype,  named  "Firefly,"  won  the  Gold  Cup 
Handicap  in  a  recent  boat  race  against  eighteen  competitors. 

British  automobile  makers  are  currently  testing  experimental 
models  of  cars  having  bodies  of  specially  treated  rubber- plastics 
compounds,  sandwiched  between  bonded  plywood. 

It  is  claimed  for  these  plastics-bodied  cars  that  they  do  not 
squeak,  arc  soundproof,  lightweight,  and  have  insulation  against 
heat  and  cold. 

An  outstanding  example  of  the  wide  use  now  bring  made  of 
plastics  in  aircraft  furnishing  is  Britain's  latest  luxury  "flying 
boat,"  the  four-engined  Short  Solent,  now  being  built  for  opera- 
tion on  Far  Eastern  routes. 

The  convertible  seat-bunks,  collapsible  tables  and  other  fur- 
niture provided  for  the  aircraft's  pas-<nn<  -r*  and  crew  arc  of 
Plastofly,  a  new  British  plastics  material,  possessing  great 
strength  and  light  weight. 

German  Plastics  Houses 

According  to  reports   from   Germany,  prefabricated   )>' 
houses,  costing  about  $1200  each,  are  being  produced  in  large 
quantities  at  a  Sienu-n»tadt  factory  for  export  to  England.  Amer- 
ica, Russia  and  Krai 

The  plastics  \valU  of  tln--r  houses  arc  made  of  a  by-pmdnrt 
of  coal,  "creased"  to  take  up  expansion  and  contraction  caused 
by  weather  variations,  and  only  1  In"  thick. 

Doors,  windows,  ceilings,  floors,  kith*,  sinks,  cupboards  and 
wiring  and  heating  pipes  arc  made  entirely  of  i-l.i-1 

The  constructors  claim  that  a  complete  plastics  house  of  this 


94 


PLASTiCS 


AUGUST  1946 


type  can  be  carried  on  a  five-ton  truck  and  assembled  in  com- 
paratively few  hours  by  three  unskilled  laborers. 

New  Type  Waxes 

The  British  Abril  Corp.  is  now  manufacturing  high-tempera- 
ture synthetic  waxes,  non-toxic  and  extremely  inert,  comprised 
of  monomeric  substances  of  practically  pure  chemical  entities 
built  from  long  carbon  chain  structures,  with  melting  points 
ranging  from  65"  C  to  280°  C. 

British  Footwear 

Due  to  extensive  research  by  British  plastics  experts  in  con- 
junction with  shoe  manufacturing,  the  possibility  of  improvement 
in  British  footwear  seems  imminent. 

"Patent"  boots  and  shoes,  which  almost  completely  disappeared 
from  shops  early  in  the  war,  because  of  the  shortage  of  leather, 
are  gradually  becoming  available  again.  Comfortable  and  smart, 
these  have  uppers  of  a  leather-type  plastics  on  a  textile  base, 
with  soles  of  vinyl-type  plastics. 

*        *        * 

Plastics  in  Mexico 

A  modern  plastics  molding  department,  at  present  producing 
combs,  cosmetic  containers,  buttons,  and  toys,  is  an  important 
activity  of  Cia.  Industrial  Importada,  S.  A.,  Mexico,  founded 
more  than  20  years  ago  as  an  import  business,  by  Max  Shein, 
its  present  president.  Firmin  Fulda  is  general  manager. 

The  company  inaugurated  its  plastics  department  in  1941,  with 
two  horizontal  injection  molding  presses  bought  in  the  United 


Row   of   the  4-oz   injection   molding   presses   built 
by    Cia.    Industrial    Importada    for    its    own    use 

States.  Priorities  preventing  the  purchase  of  additional  machines 
during  the  war,  the  company  built  10  of  its  own  injection  mold- 
ing presses,  designed  by  its  technical  director  Joseph  Yakovlaff. 
It  is  now  building  another  series  of  presses,  of  9-oz  capacity. 
All  of  its  raw  plastics  materials  are  bought  in  the  U.  S.  END 


MANUFACTURER  WANTED 

to  mold  and  merchandise  new  line  of  patented 
WHISTLING  BALL  TOYS 

on  royalty  basis. 

Samples  available  /or  inspection 

Box  99,  %  PLASTICS,  185  N.  Wabash  Ave., 
Chicago 


NEW!     IMPROVED! 


REZ-N-GLUE 

Sticks  everything  to  everything.  Dries  fast, 
but  not  too  fast  for  handling  large  pieces. 
Now  used  extensively  in  such  industries  as 
handbags,  display  fixtures,  decorating,  etc. 

WATER  WHITE 
TRANSPARENT 

A  mild  type  of  adhesive,  perfect  for  cementing  mirrors 
to  plastic  without  affecting  either,  also  leather,  cloth  or 
wood  to  plastics  or  to  each  other. 

TRIAL  GALLON  $5.5?    F.O.B.  FACTORY 

ORDER! 

SCHWARTZ  CHEMICAL  CO. 

326-328  West  70  Street,  New  York  23,  N.  Y. 


INSTANTLY  removes  all  foreign  sub- 
stancei   from  Lucite   and  Plexiglas. 

"RF7.N-DYri  "    A   single   solution  Cold  Dip  Dye  to 
fast  color  plastics.  21  Different  Colors. 


item  made  in  plastics  sends  forth  its 
'  own  bid  for  Sales  Appeal,  Durability  and 
the  savings  of  light  weight. 

But  it's  knowing  how  to  use  plastics  that  spells 
the  difference.  That's  why  your  work  at 
Magnetic  Plastics  is  custom  moulded 
from  the  plastics  that  best  withstand 
the  wear  their  job  demands. 

Ask  us  to  help  you  see  what  plastics 
can  do  in  your  business.  lust  send 
photo,  sample  or  specifications,  and 
we'll  tell  you  quickly  if  it  can  be 
made  in  moulded  plastics. 


THE  MAGNETIC  PLASTICS  CO. 

1900  EUCLID  BLDG.      •     CLEVELAND   15,  OHIO 


AUGUST  1946 


PLASTICS 


95 


Matfic.  lltAead 


From  SARAN  monofilaments  come  new 
fabrics  of  intense  beauty  and  remark- 
able durability  —  fabrics  that  simply 
defy  dirt  and  stains! 

SARAN  BY  NATIONAL  is  proving  its 
ability  today  in  upholstery  fabrics, 
auto  seating,  luggage,  handbags,  shoes 
—  a  really  new  future  for  thousands 
of  modern  products! 

Our  technical  facilities  are  available  lor  the 
study  ol  your  product.    Writ*  today. 


ODENTON-  MARYLAND 


UNIVERSAL  HYDRAULIC  MACHINERY  COMPANY 
Specialists  in  Hydraulic  Equipment 

HYDRAULIC  PRESSES:  fS«'oSS * S'-Sr'^ 

dla.  raa.  4  ooenlno  100-ton  cap.;  t—»-j.la".  10-  dla.  ramj.  71-ton  cap.; 
1— 14-jiT.  «*  dia.  ran.  75-ton  oap.;  1—  HTi4»-;  !— «-  dla.  ramj.  100- 
ton  oap.;  1— MTU4-  10-  dla.  ram.  100-ton  cap.;  3— irill*.  Ttt'  dla. 
raaM.  M  too  oap.;  1— li"ill-,  TH"  <"•-  ram.  75-ton  eap  •  1—  UCilS". 
I-  dla.  run..  75-ton  oap.;  1— (OO-lon  Wauon  Htlllman  24-i24".  1«-  dla. 
raai;  1— M-iM".  1»-  dla.  ram.  l»0-ton:  >— SO-iJO".  14"  dla  ram..  WO  ton 
oap  Priil-H:  I  -.National  Triplex  I  Ol'lt  400**  ;  1— Mill  Trlploi.  1% 
lil'M  UM«;  1— Wauon  Htlllman  4  plunrr  box  tnw;  t  OPM  4400*:  1 
Hole  Snaw  llf  11.  44  <IPM  1100*  with  newoontrol:  t— Vlokari  17  GPU 
10M*;  1—4  pliinfor  I  OPM  2150*:  Aocumuliton:  2  Wauon  Btllltnan 
hrtr  pnoumaUe  trp«.  l.M  OPS  5500*  praemre  with  Br-paH  »aln:  1— «  Jl 
OPS  Jeeo*  pneeura:  wellbud  Upt  5M,  OPS  MOO*  praemre:  KXTRI'DKKS. 
MILLS.  CALCKDBU.  MIXERS.  LABORATORY  PKB8W8.  eto. 


285  Hudson  Street.  New  York  City 


FOR    SALE 

2 — Busch-Sulzer    Hydraulic    Compression    Molding 

Presses,  capacity  150-200  tons  each. 
2 — 60-ton  Oil  Qear  Puinpa  Included  with  above. 

CHARLES   I.   TAOER 
Consolidated  Staple  Co.,  Inc. 

1*   Weetter   St.  New   York.    N.   Y. 


AUSTIN  TOOL  &  MFG.  CO. 

1159  E.  A3rd  STREET       -:-       CLEVELAND  3.  OHIO 
EXpr.si    1000 

DISIGNIIS  PLASTIC  MOLDS  SUILDUS 

QvotiKoM  Wltkln  4« 


ENGINEERING 


By  LEWIS  WINNER 


Solvents  in  Processing 

Proper  selection  of  solvents  lias  become  as  important  a  fac- 
tor in  plastics  processing  as  has  the  choice  of  the  basic  ingre- 
dients. The  solvent  must  be  capable  of  not  only  maintaining  the 
fundamental  chemical  structure,  but  retaining  the  physical  char- 
acteristics and  the  eye-appeal  finish,  as  well.  Solvents  that  tend 
to  evaporate  too  rapidly  may  produce  uneven  films,  while  those 
tliat  evaporate  too  slowly  may  result  in  films  which  are  in>ulh- 
ciently  hard. 

For  organic  plastics  like  cellulose  nitrate,  normal  butyl  ace- 
tate has  been  a  popular  solvent. 

It  is,  however,  relatively  expensive.  To  reduce  cost  it  is  often 
diluted  or  replaced  by  mixtures  of  two  or  more  ketones  with 
each  other,  and  mixtures  of  one  or  more  ketones  with  one  or 
more  alcohols.  A  new  type  of  solvent  was  recently  discovered 
by  Reginald  Francis  Buller,  West  Los  Angeles,  Calif.,  the  new 
solvent  comprising  mixtures  of  methyl  isobutyl  ketone  with  di- 
isobutyl  ketone  and  one  or  more  alcohols  of  aliphatic  character. 
These  solvent  mixtures  were  found  to  have  a  high  dilution  ratio  ; 
(dilution  ratio  can  be  expressed  as  a  numerical  measure  of  the 
solvent  power  of  a  substance  for  a  given  material).  The  im- 
proved solvent  was  also  found  to  provide  lacquers  with  an  ex- 
tremely high  "blush  resistance;"  (lacquers  having  a  low  re- 
sistance to  humidity  may  absorb  water  from  the  surrounding 
atmosphere,  causing  precipitation  in  the  drying  film  of  some  or 
all  of  the  dissolved  solids,  resulting  in  the  so-called  "blushing  ;" 
this  term  might  also  include  other  clouding  effects  which  appear 
on  the  film). 

Lower  Viscosities 

Since  the  viscosities  of  solutions  of  cellulose  nitrate  and  other 
plastics  with  methyl  isobutyl  ketone-diisohutyl  ketone  mixtures 
are  lower  than  those  of  equal  concentrations  of  cellulose  nitrate 
in  normal  butyl  acetate,  less  solvent  is  required.  The  propor- 
tions of  methyl  isobutyl  ketone  to  diisolmtyl  ketone  in  the  solvent 
mixtures  can  be  varied.  It  was  found,  however,  that  for  cellu- 
lose derivatives,  mixtures  having  approximately  the  same  over- 
all vaporation  rate  as  normal  butyl  acetate  were  preferred.  In 
test  compositions  a  mixture  of  86.7  parts  (by  weight)  of  methyl 
isobutyl  ketone  with  13.3  parts  (by  weight)  of  diisobutyl  ketone 
proved  to  have  an  evaporation  rate  of  1.0  as  compared  to  normal 
butyl  acetate.  Preferred  mixtures  of  methyl  isobutyl  ketone 
with  diisolmtyl  ketone  were  within  the  ratio  range  of  91  :9  to 
about  82:18,  respectively.  The  solvent  can  also  be  used  for 
copolymers  of  vinyl  chloride  and  vinyl  acetate,  phenolaldehyde 
resins,  acrylic  resins,  etc. 

Elasto-PfasrJc  Compounds 

I  icvelopment  of  rubber-like  materials,  initiated  in  the  prewar 
era,  to  form  elasto-plastics  compounds,  has  resulted  in  several 
unusual  products.  It  was  recently  disclosed,  for  instance,  that 
an  elasto-plastic  composition  using  reclaimed  rubber,  wood  rosin 
and  coumarone-indene  type  resins  has  been  developed  for  glaz- 
ing window  sashes.  Prepared  by  Grant  S.  Merrill,  St.  Paul, 
Minn.,  the  composition  is  said  to  be  superior  to  linseed  oil  and 
ground  calcium  carbonate  putty  in  that  it  firmly  adheres  to 
wood,  glass  or  metal,  yielding  internally  with  the  distortion  or 
warping  of  these  materials,  and  will  withstand  hi?her-than-nor- 
ni.il  MIM  temperatures  and  quickly  alternating  extremes  01  hut 
and  cold.  The  improved  compound  can  be  applied  with  a  glaz- 
ing gun,  minimizing  waste  and  affording  sealing  uniformity. 

>i-\eral  types  of  resins  were  used  with  reclaimed  rubber.  These 
included  the  cumar-type  resins  which  are  derivable  from  coal 
tar  naphtha,  and  /inc-treatod  and  lime-treated  rosins.  Polyvinyl 
lmtyr.il  resins,  dioleline  poly  sul  fide-type  compounds  and  butyl 
rubber  compositions  have  been  used  in  place  of  reclaimed  rubber 
materials. 

In  one  type  of  glazing  ci>ni|xiund.  reclaimed  inner-tube  rubber 


96 


Pl.t  MI- ir* 


Al'M'ST   !? 


of  neutral  or  low  alkalinity,  wood  rosin,  cumar  resin,  powdered 
calcium  carbonate  whiting,  short  fibre  asbestos  and  a  hydrocar- 
bon solvent  were  used.  The  rubber  and  asbestos  fibre  were 
milled  together  on  a  rubber  mill  for  about  20  min;  the  blended 
composition  was  then  fed  into  a  mixer  and  whiting  and  rosin 
gradually  added.  After  the  solids  were  uniformly  mixed,  the 
addition  of  solvent  was  slowly  made.  The  solvent  had  a  boiling 
range  of  305°  to  365°  F,  which  high  boiling  point  prevents  too 
rapid  evaporation. 

The  glazing  compound  has  found  wide  use  for  doors  and  other 
large-surface  units  where  resistance  to  shrinking,  sagging  and 
shock  are  important. 

Cellulose  Casings 

In  the  use  of  regenerated  cellulose  plastics  tubing  as  a  casing 
for  food,  a  number  of  processing  problems  have  arisen  in  con- 
nection with  the  drying,  shrinking,  and  particularly  with  the  ex- 
pansion, prompted  by  stuffing,  curing,  and  cooking  of  the  tub- 
ing fillings.  One  of  the  methods  used  in  attempting  to  overcome 
these  problems  provided  for  squeeze  rollers  to  expand  the  tubing. 
Requiring  a  moving  belt  for  support  of  the  tubing,  a  tensile 
stress  strain  was  introduced,  causing  tubing  breakage;  and,  in 
addition,  abrading  and  scuffing  injured  the  tubing,  in  some  in- 
stances puncturing  it,  thus  affecting  the  sealing  properties. 

Frank  H.  Reicheil,  Fredericksburg,  Va.,  has  overcome  these 
difficulties  in  a  method  which  supports  the  tubing  on  the  surface 
of  a  body  of  water,  while  keeping  entire  surface  of  the  tubing  wet 
by  means  of  a  fluid  spray.  To  soften,  the  tubing  is  plasticized. 
With  cellulose  hydrate  tubing,  an  aqueous  solution  of  glycerine 
or  glycol  has  been  found  satisfactory. 

By  keeping  the  tubing  under  expansion  uniformly  wet,  it  has 
been  possible  to  control  expansion,  thus  avoiding  surface  shrink- 
age, drying  or  breakage. 

Light  Polarizing  Procedure 

Plastics  engineering  details  covering  the  widely-used  light- 
polarized  plastics  sheets  (Polaroid)  were  recently  disclosed  in 
a  release  of  the  patent.  In  describing  his  discovery,  Edwin  H. 
Land,  Cambridge,  Mass.,  said  that  he  had  found  that  dichroic 
light  polarizers  and  dichroic  stereoscopic  images  could  be  formed 
by  applying  a  dichroic  dye  or  stain  to  the  surface  of  a  sheet 
of  molecularly  oriented  transparent  plastics  such  as  polyvinyl 
alcohol. 

Tests  disclosed  that  it  was  possible  to  use  all  transparent  plas- 
tics made  from  polyvinyl  alcohol  and  which  could  be  converted 
or  regenerated  from  sheet  form  to  polyvinyl  alcohol.  These 
materials  included  polyvinyl  acetate  and  polyvinyl  formate,  as 
well  as  the  copolymer  of  polyvinyl  acetate  and  polyvinyl  chloride. 

A  hydrolyzing  agent  such  as  a  diluted  solution  of  sulphuric  or 
hydrochloric  proved  effective  for  regeneration. 

In  testing  the  use  of  polyvinyl  alcohols,  it  was  found  that  poly- 
vinyl acetal  and  similar  derivatives  were  generally  less  hydro- 
philic  than  polyvinyl  alcohol  itself.  This  discovery  emphasized 
the  need  for  the  use  of  the  dichroic  stain  on  the  thinner  of  the 
two  layers  to  provide  light  polarization. 

The  dyed  layer  was  less  subject  to  moisture  deterioration,  and 
resistant  to  curling — an  important  feature  not  present  in  previ- 
ously prepared  polarizers  made  from  stretched  and  dyed  poly- 
vinyl alcohol. 

Extent  of  Conversion 

The  extent  to  which  the  surface  of  the  sheets  could  be  con- 
verted was  found  to  be  quite  important.  For  preferred  results, 
surfaces  with  only  partial  regeneration  proved  most  suitable,  with 
some  of  the  surface  molecules  retained  in  their  original  condi- 
tion. Thus  the  treated  layer  could  be  considered  as  a  mosaic  or 
mixture  of  polyvinyl  alcohol  and  the  original  material  of  the 
sheet. 

To  stretch  the  sheets,  Mr.  Land  softened  them  at  approximate- 
ly 120°  C.  In  producing  sheets  for  stereoscopic  effects  with 
dichroic  stains,  polyiodide  stain  or  dichroic  direct  cotton  dyes 
were  used. 

To  produce  sheets  as  filters  for  infra-red  rays,  right-angle 
molecular  orientation  was  employed.  By  varying  the  angular 
relation  between  the  directions  of  molecular  orientation  the  den- 
sity of  the  filter  could  be  controlled.  This  was  the  basis  for  the 
development  of  the  familiar  sun-filter  glasses. 

Parallel  molecular  orientation  of  the  sheets  supplied  light  pol- 
arization. ,  END 


Q.T.C. 

DESIGNING 

PLASTIC  MOLDS 

EXPERIENCED  &  RELIABLE 

1.  COMPRESSION,  TRANSFER 

&  TOP  RAM 

2.  INJECTION,  INCLUDING 

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3.  EXTRUSION 

4.  PRODUCT  DESIGN 

5.  PRODUCTION  ENGINEERING 

COMPLETE  MOLD  BUILDING  FACILITIES 
write  or  phone 

QUARNSTROM  TOOL  CO. 

6698  E.  McNichols  Road,  Detroit  1 2,  Michigan 
Telephone:  TWINBROOK  1-8282 


INJECTION 


AUGUST  1946 


PLASTtCS 


97 


IF  YOU  WANT  OUTLETS 
CONTACT  US 


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or   General    Merchandising   and 


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Pruning  Units.  Comprising  Pr«ii«t,  Pumps,  Motors,  Hydraulic,  Steam 
and  W*t»r  Valves,  Automatic  Tim«n  and  All  Accessories.  The  75  Ton 
Unit,  for  10-  and  ir  Shellac  and  10'  Vinylite  Records,— (he  100  Ton 
Units  for  12"  Vinylite  Records.  Prompt  Deliveries. 

New  INDUSCO  157  Ton  and  400  Ton  Mobbing  Presses,  \T  Daylight, 
Hardened  Steel  Anvils,  Each  Complete  with  Either  Hand  or  Power 
Driven  Pump  with  Necessary  Piping  and  Accessories. 

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Various  Sixes  and  Capacities  of  Used,  Guaran- 
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On  Any  Job  No  Matter  How  Small 

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and    Repair  Service.      Send   us  your  inquiries. 

AARON  MACHINERY  CO. 

41  Cretfey  St..  N.  T.  C.    11  T.I.   Co.oJ  4-0421 


INJECTION  MOLDING— FABRICATING 

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Urmn  In  nny  quantity.    Ix>w  Mold  Colt*.   Complete  fab- 
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FLAATIC   PRODUCT*   CO. 

211    71k   "I.   ».K.  li.  ,.i      r    I  <  nnlaK   2.   Okie) 


Chicago  is  to  be  the  locale  of  the  1947  annual  plastics 
eipositions  of  both  the  Society  of  Plastics  Engineer)  and  the 
Society  of  the  Plastics  Industry,  according  to  plans  announced 
by  those  respective  organizations. 

The  3rd  Annual  Exhibit  sponsored  by  the  SPE,  as  announced 
in  plastics  July  1946,  is  to  be  held  during  the  week  of 
January  27,  at  the  Coliseum,  Chicago. 

The  second  National  Plastics  Exposition,  held  under  the 
sponsorship  of  the  SPI,  if  scheduled,  concurrently  with  the 
organization's  annual  convention,  for  May  5  to  II,  at  the 
Coliseum.  Conference  headquarters  are  to  be  at  the  Stevens 
Hotel. 

In  announcing  its  choice  of  Chicago,  the  SPI  stated  that 
it  was  made  because  of  the  great  concentration  of  plastics 
industry  in  the  central  region,  and  the  potential  development 
of  that  area. 


Elections  at  SPI  Hartford-Springfield  Chapter 

H.  E.  Griffith,  sales  manager,  Plax  Corp-  of  Hartford,  Gum  . 
was  elected  chairman  of  the  Hartford-Springfield  chapter  of  the 
Society  of  the  Plastics  Industry,  at  a  banquet  and  meeting  re- 
cently held  in  the  Hotel  Sheraton,  Springfield.  Edward  W.  Vaill. 
of  the  Bakelite  Corp-'s  Hartford  office,  was  re-elected  secretary- 
treasurer  of  the  chapter. 


ASTM   Holds  Annual  Meeting 

Extensive  interest  was  indicated,  at  the  49th  annual  meeting  of 
the  American  Society  for  Testing  Materials,  in  that  organiza- 
tion's expanding  work  on  specifications  and  tests  for  materials 
and  methods  of  evaluating  assemblies  of  these  materials  in  vari- 
ous forms. 

The  meeting,  held  at  the  Hotel  Statler,  Buffalo,  throughout  the 
week  beginning  June  24,  1946,  featured  technical  sessions,  appa- 
ratus exhibits,  and  committee  meetings.  There  were  eight  sym- 
posiums with  technical  papers  ranging  in  number  from  four  to 
fifteen,  and  covering  a  wide  diversity  of  fields,  as  well  as  various 
other  sessions. 

Officers  were  elected  for  1946-1947,  as  follows:  Arthur  W. 
Carpenter,  manager  of  testing  laboratories.  The  B.  F.  Goodrich 
Co.,  president ;  Richard  L  Templin,  assistant  director  of  research 
and  chief  engineer  of  tests.  Aluminum  Co.  of  America,  vice 
president.  Mr.  Carpenter  succeeds  J.  R.  Townsend,  who  con- 
tiniirs  on  the  board  of  directors  as  past-president  for  three  years : 
Mr.  Templin  will  serve  with  senior  vice  president  T.  A.  Boyd. 


Manufacturing  Chemists  Elect  Officers 

Election  of  officers  and  executive  committee  members  of  the 
Manufacturing  Chemists  Association  of  the  United  States  took 
place  at  that  organization's  annual  meeting  in  June.  Charles  S. 
Mimsiin.  chairman  of  the  executive  committee.  U.  S.  Industrial 
Chcinirals..  Inc..  was  elected  president;  Leonard  T.  Bealc.  presi- 
dent of  the  Pennsylvania  Salt  Mfg.  Co.,  and  H.  O.  C.  Ingraham. 
vice  president  of  (ieneral  Chemical  ("<>..  were  elected  vice  jiresi- 
dents ;  J.  W.  Mclaughlin,  Carbide  &  Carbon  Chemicals  Corp., 
trrasiirrr;  and  Warren  N.  Watson.  Washington,  D.  C.,  secretary. 


New  Vice  President  of  AM  A 

E.  A.  Throckmorton,  president  of  Container  Testing  labora- 
tories, Chicago,  was  recently  elected  vice-president  of  the  Ameri- 
can Management  Association.  He  will  be  in  charge  of  the  as- 
sociation's packaging  division,  and  will  supervise  the  packaging 
meetings,  research  ami  publications  of  the  AMA.  and  its  annual 
Packaging  Exposition 


•is 


f  I.  .\ST  US 


AH.l'ST    1'Mf. 


MODERN  ORGANIC  FINISHES 
By  Rollin  H.  Wampler 

Dealing  with  modern  organic  finishes  in  their  application  to  in- 
dustrial products,  this  book  is  primarily  one  of  methods.  It  de- 
scribes these  finishing  materials,  and  equipment  for  their  applica- 
tion, drying,  and  conveying,  clearly  and  interestingly,  placing 
emphasis  on  proper  selection  and  use  of  materials  and  equipment 
for  best  and  most  economical  results 

The  author,  whose  experience  in  the  paint  industry  has  been 
extensive,  has  supplemented  his  own  knowledge  of  his  subject 
with  a  quantity  of  additional  specific  information  from  a  variety 
of  other  authoritative  sources,  the  result  being  a  well  rounded- 
out  presentation  of  practical  information  and  details.  Acknowl- 
edgment of  these  sources  is  made  by  the  author  in  the  opening 
pages  of  the  book. 

The  book  is  divided  into  six  sections,  headed,  respectively: 
"Modern  Organic  Finishing  Materials" ;  "Modern  Application 
Methods" ;  "Drying  Methods" ;  "Product  Handling  in  the  Fin- 
ishing Department"  ;  "Finishing  Processes" ;  and  "General  Con- 
siderations." Each  section  contains  a  requisite  number  of  chap- 
ters dealing  with  the  division's  subject  matter.  The  volume  is 
adequately  illustrated,  and  there  is  a  comprehensive  index,  as 
well  as  a  bibliography. 

Prepared  for  all  industrial  users  of  organic  protective  and 
decorative  coatings,  it  is  felt  that  this  volume  should  be  of  par- 
ticular interest  to  industrial  chemists,  finishing  superintendents, 
technicians,  production  executives,  purchasing  agents,  and  all 
others  who  are  concerned  with  these  materials  and  application 
equipment. — Chemical  Publishing  Co.,  Inc.,  Brooklyn,  N.  Y., 
452  pages,  $8.50. 


METALLIZING  NON-CONDUCTORS 
By  Samuel  Wein 

This  is  a  comprehensive  survey  of  the  technical  and  patent 
literature  relating  to  the  subject  covered  by  its  title. 

After  a  historical  survey  of  the  development  of  the  field,  the 
author  reviews  the  work  done  on  mechanical  films,  in  which 
"the  conducting  medium,  in  the  form  of  a  fine  powder,  is  held 
mechanically  to  the  given  surface" ;  chemical  reproduction  films, 
largely  devoted  to  the  silverizing  process  but  including  copper 
and  other  metals,  cathode  sputtering  and  metal  spraying;  metal- 
lic paints;  and  finally,  plating. — Metal  Industry  Publishing  Co., 
\t-u'  York.  N.  Y.,  62  fanes.  $2.00. 


COMING  IN  SEPTEMBER 

plastics 


1 I )  An  article  on  some  of  the  problems  involved  in  the  plas- 
tics  coating   of   various   materials,    plus   excellent   illustra- 
tions of  a  number  of  interesting  uses. 

(2)  An   authoritative   survey  of  the   developments   in   the   use 
of  plastics  in  conjunction  with  metals,  textiles,  wood,   pa- 
per,  inorganics,   and   other  materials. 

(3)  A  detailed   description   of  the   process   of   manufacturing 
plastics  playing  cards. 


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INQUIRIES  AND  PROBLEMS 
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ALGONQUIN  4 


Control  Skin  Irritations 

TARBONIS  cuts  absenteeism!  Dermatitis,  due  to 
urea  and  phenol  formaldehyde  resins  and  powders,  in 
addition  to  many  other  plastic  compounds,  has  been 
practically  eliminated  in  many  plants  through  the  use 
of  TARBONIS. 

Not  merely  a  protective, TARBONIS  is  also  effective 
in  clearing  up  a  high  percentage  of  stubborn  skin  condi- 
tions encountered  in  industry.  Easy  to  apply— nothing 
to  remove.  Pleasant,  odorless,  greaseless,  stainless. 


THE  TARBONIS  COMPANY 

430O  Euclid  Ave.,  Dept.  P        Cleveland  3,  Ohio 

Please  send  me  a  good  sized  jar  of  TARBONIS  and  com- 
plete information. 

NAME 

ADDRESS 

CITY..  ..ZONE..      ..STATE.. 


AUGUST  1946 


PLASTtCS 


99 


Advertiser 

Aaron   Machinery  Co 

Accurate   Molding   Corporation   . 

Aiai  StMl  *  Forge  Co 

American   Molding   Powder  and 

Chemica  I  Corp 

Amot  Molded  Plastics 
Arrow  Plastics  Company 
Austin  Tool  *  Mlg.  Co 

lamberger,  A    

lattalen,  L   H 

lellco  Plastics.  Inc.  .. 
loonton  Molding  Company 
Irilhart,  Arnold,   Ltd. 
Catalin  Corporation   

Cello. Nu   Products  Inc. 

Callo-Plastic  Chemical  Co 

Celleplastic  Corporation 
Consolidated  Staple  Co..  Inc. 
Continental  Plastics  Corporation 
Continental  Screw  Company 
Cumberland    Engineering    Co. 
Detroit   Mold    Engineering 

Company    

Detroit  Stamping  Co 

Dow  Chemical  Company,  The 
Daall    Molding   Corporation 
Ekstrom,  Carlson  a  Co 

Electric  Auto-Lite  Company.  The 
Farmworth  Engineering   Inc. 
Falsenthal.  G  .  I  Sons 

Fisher  Chemical  Company   

General   Electric  Co 

General    Industries  Company.  Th< 

Gering   Products  Inc 

Girdler   Corporation,   The 

Goodman,    Mnjamin,   Inc 

Goodrich.  I.  F  .  Chemical  Co.  .. 
Grays  Harbor  Industries.  Inc.  ... 
Great  American  Color  Company 


Agency 


Fog. 


.Rothschild   Advertising   Agency   M 

.Stockwell  t   Marcuse  *l 


.H.  W.  Falrfai  Advertising  Agency  Inc...  74 

Siedner  and  Van  Riper.  Inc.   . 

Powered    Company.   The    97 

M 

.H.  W.  Fairfai  Advertising  Agency,  Inc.  70 

Gunn-Mears  Advertising   Agency   M 

.Rea,   Fuller  t  Company   M 

A.  J.  Slomanson,  Advertising    7 

Henri  La  Mothe  Agency  lack  Cover 

.Walter   J.   Gallagher.   Advertising 

Second  Cover 

.Weiss  and  Geller  Advertising  13 

.McCarty   Company,   The.  78 

M.  C.  Dledrich  41 

H 

.Jim  Duffy  Company  7* 

Rossi    *    Hirshion    it 

Richard  Thorndike  Precision  Advg H 


.Charles  M.  Gray  ft  Associates   II 

Charles  Schweim  Co 10 

.MacManus,  John  ft  Adams,   Inc f 

.Gunn-Mears  Advertising   Agency    ift 

.Cummings,    Brand   ft   McPherson 

Advertising    . .   t4 

Ruthrauff  1  Ryan   Inc 3* 

Li.ber  Advertising  Co .  ...  43 

.Frelwald  ft  Coleman  Advertising  92 

.  lenton  1  lowles.  Inc 33 

Fuller  ft  Smith  ft  Ross  Inc X 

.M.  C.  Diedrich 4 

. Roche,  Williams  ft  Clear,,  Inc 45 


. Griswold-Eshleman   Co.,   The    . 
.  Frederick  E.  laker  and  Associates 


35 
17 


DUALL  MOLDING  CORP. 

Injection   «*aj   Coit.pr.itio.    kUU.n 

Toys — Novelties 

Or»«ne»taJ  PtevMe* 

•SM)    M«+aJ    SpecWtiei 

Conpfct.  T«ol   Roo«    F*cNrties 

2*7-271  Wycfcoff  St.          Brooklyn  N.  T.          MA  in   5-1829 


— "KRIEGR-O-DIP"— 

ROT  AND  COLD 
Dye*  for  All  Types  ot  Plastics 

Manufactured    By 

KRIEGER  COLOR  &  CHEMICAL  CO. 

Member  ol  the   S.P.I. 

Tel.  Hlll.ide  7M1  153!  Santa  Monica  Blvd. 
HOLLYWOOD   II.    CALIF. 


WANTED:  A-l  DEALERS 


New  line  fabricated  novelties  for  dept.  stores,      ,  , 

gift  ihops,   etc.     Writ,  for   territory,   samples,    <PLEXTTET> 
•tc. 

PLEXITE    PLASTICS    CORPORATION 

210    W.    Michigan    St.  Milwaukee    1.    Wlo. 


PLASTIC    CEMENT 

Pact    Drying.   eo«Hy   applied,    no    pressure   reejulred. 
F.r  meewthf  pUtttc  Items  en  elivpley  terdi. 

e«ct  a>U«ttc  assembly. 
AwUbt*  »a»a»ec4*'afe/y  in  oee  a*W  fve  «a//cwj  caws. 

TEXON     INDUSTRIAL     CORP. 


Advertiier                                      Agency  Pag* 

Hy-Speed    Press  Company  12 

Hydraulic    Press   Mfg.   Co.,  The    ..Jay  H.  Maish  Company,  The 

Industrial   Equipment  Company   ...Louis    F.    Herman   Advertising  Agency. 


Industrial  Molded   Products  Co.     .Wesley  E.  Sharer  ft  Associates 

Karlstad,  Andrew  C 

Kaempf.  H.  «.,  Co 

Kingsley  Gold  Stamping 

Machine    Co Continental  Advertising  Service 

Kirk.  F.  J..   Molding  Co Cory  Snow.  Inc 

Krieger  Color  t  Chemical 

Company  .  Warren   P.    Fehlman   Adv.   Co. 


VI 
54 

.   *4 
K 

(4 

101 

100 


13 
I 

.  II 
.  3< 

•5 
.  10 
.  57 

101 


S 

74 

•4 
«4 


Kuhn  ft  Jacob  Molding  ft  Tool  Co.  Eldridge-Northrop.    Inc.  77 

Kurj  Kasch.  Inc. Klrcher.   Helton  ft  Collett 

La  Rose,  W.  T.,  1  Associates  Aldridge  and  Preston  Advertising 

Maas  ft  Waldsteln  Company Hutchins  ft  Graves,  Inc.   . 

Mack   Molding   Company,    Inc.      ..George   Homer  Martin    .. 
Magnetic    Plastics    Company,    The  Gregory   House,   Inc. 

Metaplast  Company,  Inc Sam  J.   Gal  lay  Company 

Meyercord  Co..  The   C.  C.  Fogarty  Company       

Michigan  Chrome  t  Chemical  Co. Karl  G.   lehr  Advertising  Agency 

Michigan   Molded   Plastics,    Inc.    . .  Wallace-Lindeman.    Inc 

Midland  Plastic  Molding  Company.      .  ... 

Mosinae   Paper  Mills  Company   ...Klau-Van    Pietersom-Dunlap   Associates 

Inc 

National    Lock   Company    L  W.  Ramsey  Advertising  Agency,  The 

National  Plastic  Products  Co.,  The  Joseph  A.   Wilner  Company,  The   . . 

Nicholl  Hard  Chrome  Service 

Northern   Industrial   Chemical   Co.  Callaway  Associates,  The   (4 

Oiley.  John  H..  Company   T2 

Pennsylvania    Coal    Products 

Company    Lee-Murray  Advertising  Agency   102 

Plaskon    Division.    Libbey-Owens- 

Ford  Glass  Company   Meldrum  ft  Fewsmith  Advertising 

Plastics  Products  Co A.  F.  Ugotti  Advertising 

Plastics  Service   Engineering   

Pleiite  Plastics  Corporation  

Ouarnstrom  Tool  Co 

Radio   Receptor   Company,   Inc.       John  A.  Finneran 

Rohm  t   Haas  Company Newell  Emmett  Company 47 

Schwartl  Chemical  Company   Walter  W.  Wiley  Advertising  

Slegel.   M.   I.   Associates   Craig   E.   Dennison   Advertising  Agency  •> 

Steiner.   George,  Company   

Tarbonis  Company,  The  L.  6.  Malson  ft  Company  .. 

Tennessee    Eastman    Corporation        Kenyon  ft   Eckhardt  Inc.    II 


Tenon    Industrial   Corp 
Universal    Hydraulic   Machinery 
Company    ...................  Gunn-Mears   Advertising   Agency 

Van  Dorn   Iron  Works  Co.,  The     .Hubbell  Advertising  Agency.  The 
Waterbury  Companies,   Inc.    .....  Manternach,  Inc  ..... 

Worcester  Moulded  Plastics  Co.   ..C.  Jerry  Spaulding.   Inc. 
Wrigley,  Wm.,  Jr.,  Company  .....  Ruthrauff  t    Ryan,    Inc. 


H 
21 
«3 

Third  Cover 
..  73 


CLASSIFIED    ADVERTISING 


WANTED1  Hydraulic  Press  500  ton.  48"x48"  pl*t«n.  38"  dajrllfht, 
ste»m  heated,  In  good  condition.  Need  not  h»T«  the«  ei»ct  specifications. 
Box  97,  %  Plastics,  185  N.  Wab»»h  Ate..  Chicago.  III. 

HELP    WANTED 

WANTED— Experienced  Injection  Molding  Supwrtsor.  Excellent  oppor- 
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resins  adheslves  from  Bone  filue  as  main  constituent  Only  experienced 
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Chicago.  HI 


FOR  SALE 

3  Triplex  Hydraulic  Pumps  with  7  ¥2  h.p.  Gen- 
eral Electric  Motors  (220-440  v.).    Capacity  2500 
pounds.    Delivery  15  gal.  low  pressure,  5  gal. 
high  pressure.    Wrife,  call  or  wire. 

GEORGE  STEINER  COMPANY 
1220  W.  Lake  Street  Chicago,  Illinois 

Haymarket  6027 


100 


AUGUST    1941 


Statistical  Data 

THE  shipments  and  consumption  of  plastics  and  synthetic 
resins  for  April,  the  latest  month  for  which  statistics  are 
available,  was  60,942,792  Ib,  according  to  Facts  for  Industry, 
Bureau  of  the  Census,  Series  M19H-46.  This  is  an  increase 
of  almost  50%  over  the  figure  reported  for  December,  1945,  and 
represents  a  substantial  increase  over  the  consumption  and  ship- 
ments in  March. 

Although  certain  variations  in  number  of  companies  sur- 
veyed and  manner  of  collecting  and  compiling  data  mean  that 
the  various  monthly  totals  are  not  100%  comparable,  they  may 
be  considered  a  reliable  guide  to  general  and  even  specific  trends. 
As  a  review,  here  are  the  totals  for  December  of  last  year  and 
the  first  quarter  of  1946:  December,  1945^11,539,277  Ib;  Janu- 
ary, 1946—51,719,029  Ib;  February,  1946—50,411,446  Ib;  and 
March,  1946—55,949,663  Ib. 

The  phenomenal  increase  in  the  figures  for  polystyrene  have 
previously  been  commented  on  here.  The  monthly  shipments 
and  consumption  for  this  material  over  the  five  months  begin- 
ning last  December  are  as  follows:  December,  2,239,477  Ib ; 
January,  2,727,579  Ib;  February,  3,007,122  Ib;  March,  4,011,334 
Ib;  and  April,  4,950,626  Ib.  It  will  be  interesting  to  see  how 
long  this  rise  continues. 

The  statistics  below  represent  the  shipments  and  consump- 
tion of  plastics  and  synthetic  resins  as  reported  by  77  manu- 
facturing companies  and  company  departments.  The  decrease 
in  the  number  of  manufacturers  from  that  shown  in  the  previous 
release  (Series  M19H-36)  is  due  to  the  exclusion  of  one  com- 
pany previously  reporting.  Data  for  synthetic  resins  for  protec- 
tive coatings  are  not  included.  Shipments,  for  the  purposes  of 
this  report,  include  data  for  plastics  and  resins  manufactured 
by  the  reporting  companies  or  company  divisions  and  shipped 
to  outside  users.  Consumption  refers  to  the  quantities  of  plastics 
and  resins  manufactured  and  used  by  the  reporting  companies. 


Plastics  and  Synthetic  Resins  Shipments 
and  Consumption  (Ib)      *| 


Item 


April 
1946 


March 
1946 


Cellulose  acetate  and  mixed  ester  plastics' 
Sheets 

Continuous  (under  .003)  gauge 696,486 

Continuous  (.003  gauge  and  upward) 664,833 

All  other  sheets,  rods,  and  tubes 500,693 

Molding  and  extrusion  materials 7, 1  8  1 , 1  93 

Nitrocellulose  plastics' 

Sheets 1 ,048,1  08 

Rods  and  tubes 665,853 

Phenolic  and  other  tar  acid  resins 

Laminating  (dry  basis) 2,404,966 

Adhesives  (dry  basis) 1,258,188 

Molding  materials' 1  2,483,690 

All  other  (dry  basis)' 5,314,081 

Urea  and  melamine  resins 

Adhesives  (dry  basis) 3,31  4,027 

Textile  and  paper  treating  (dry  basis) 1,012,742 

All  other  (dry  basis)* 186,583 

Polystyrene 4,950,626 

Vinyl  Resins 

Sheeting  and  film' 2,243,370 

Textile  and  paper  coating  resins  (resin  content)  1,436,258 

Molding  and  extrusion  materials  (resin  content)'''  5,265,325 
Adhesives  (resin  content)* 
All  other  (resin  content)2 

Miscellaneous  plastics  and  resins 

Molding  and  extrusion  materials',7 5,439,045 

All  other  (dry  basis)*,' 3,072,620 


656,114 
677,978 
417,599 
6,503,781 

911,081 
609,841 

2,052,005 
1,194,389 
12,286,204 
4,229,231 

3,224,959 
1,034,940 
130,296 
4,011,334 

2,161,230 
1,688,890 
*4,718,281 

'1,804,105  *M,276,241 

5,434,228 
2,731,042 


TOTAL 60,942,792  55,949,663 


"Reviled.  'Includes  fillers,  plasticizers,  and  extenders.  'Excludes  data  for  protect! 
coating  resins.  'Formerly  included  fillers,  plasticizers,  and  extenders,  on  which  basi 
April  figures  would  be  7,106,981  Ib  and  March  figures  6,664,970  Ib.  April  figure!  a 
shown  were  collected  on  resin  content  basil  and  March  figures  revised  to  comparabli 
basis.  Future  statistics  will  be  collected  on  resin  content  basis  as  shown  here.  'Cannot  b 
shown  separately  without  disclosing  the  operations  of  individual  establishments.  :'Propo 
tion  of  estimate,  2.8%.  Proportion  of  estimate,  4.7%.  'Includes  data  for  ethyl  celluloi 
urea  and  melamine,  acrylic  acid,  and  miscellaneous  molding  and  extrusion  materia 
Includes  data  for  petroleum  resins,  acrylic  acid  ester  resins,  mixtures,  and  miscellanea 
synthetic  resin  materials. 


Specify  MICCROPLATE  Super-Finish  ...  Hie  finest  of 

HHRD  cHRomium 

P1HIIRG  FOR  PIHSTII 
mOlDS  RHD  DIES 


MICCROPLATE  Super-Finish  it  a  new  improved  hard 
chromium  plating  technique  developed  by  specialists  of 
the  Michigan  Chrome  and  Chemical  Company  ...  It 
produces  high-luster  castings  —  eliminates  repolishing, 
corrosion,  pitting  and  discoloration  — prevents  material 
adhesion,  facilitates  material  flow,  reduces  wear  and 
preserves  mold  finish. 

Send  your  molds  and  dies  for  MICCROPLATC  Super- 
finish.  All  work  guaranteed.  24  HOUR  SERVICE! 


Developed  and  Manufactured  by  experienced  Plolert 


MICHIGAN     CHROME    and 
CHEMICAL    COMPANY 

6342  East  Jefferson  Avenue 
Detroit  7,  Michigan 


you 


WE'LL  MAKE  IT 

Whenever  the  problem  of  selecting  a  plastic 
molder  arises  consult  KIRK  first.  The  variety  of 
products  we've  produced  is  your  assurance  that 
you'll  be  right  with  KIRK. 

Don't  fuss  with  problems  in  plastics  .  .  .  refer 
them  to  KIRK.  The  service  is  complete  and 
dependable. 

Retail  Store  Buyers  !  Ask  about  fast- 
selling,  profitable  products  by   KIRK. 

nri  F.  J.  KIRK  MOLDING  CO. 

I    CLINTON,       MASSACHUSETTS 


AUGUST  1946 


PLASTICS 


101 


Mcirhoms 

of  tomorrow 
arc  being 
made  today 
with 


PEXACOUTE 


•urniture  finer  than  the  finest  produced  by  the  most  highly 
skilled  craftsmen  of  the  past  is  being  produced  today  with 
PENACOLITE  room  temperature  setting  adhesives. 

\.   Take,  as  example,  the  Algonquin  Breakfront  of  the  Beacon  Hill  Collection 
pictured  above.  Manufactured  by  the  Kaplan  Furniture  Company  which 
specializes  in  authentic  reproductions  of  early  American  and  English 
furniture,  it  perfectly  duplicates  the  classical  style  and  rich  finish  of  the 
original  Boston  masterpiece. 

Thanks  to  PENACOLITE  the  joints  and  veneers  are  permanently  secured  in  strengths 
up  to  4500  psi;  are  impervious  to  heat  and  moisture  changes;  are  completely 
resistant  to  molds,  fungi,  acids,  and  organic  solvents. 

What  improvements  and  savings  can  PENACOLITE  work  in  your  operation,  on  your 
product?  Investigate  its  easy  spread-on  application,  superior  working  qualities, 
rapid  cures  at  reduced  temperatures,  and  excellent  results. 

For  information  regarding  PENACOLITE  adhesives,   write   Pennsylvania  Coal  Products 
Company.  Details  covering  intended  uses,  materials  to  be  treated,  and  production 
methods  will  enable  us  to  suggest  the  PENACOLITE  best  suited  to  your  purpose. 


PENNSYLVANIA  COAL  PRODUCTS  COMPANY 


PETROLIA.  PENNSYLVANIA 
Distributed    in   Canada    by  CANADIAN   INDUSTRIES    LIMITED.  Montreal.    Canada 


102 


PRINTED  IN  U.S.A. 

PLASTICS 


AUGUST    194fi 


Emerson    Personal 
Radio   Model   508 


Entertainment  for  millions  with  better 
reception,  smoother  tones  at  less  cost.  That's 
what  Emerson  had  in  mind  to  perfect  its  new 
personal  radios.  But  for  additional  sales 
appeal,  Emerson  also  wanted  color,  beauty 
and  utility  in  the  cabinet.  Just  as  many  other 
manufacturers  have  done,  Emerson  left  this 
part  of  the  program  to  Worcester  Moulded 
Plastics  —  to  the  time-tested  skill  and  expe- 
rience of  our  die  designers,  die  makers  and 
engineers,  and  to  our  huge  Custom  Injec- 
tion Moulding  facilities.  You,  too,  will  find 
the  cooperative  features  of  the  Worcester 
Moulded  program  advantageous  in  product 
development. 


..To  a 


Program 


Emerson     Personal     radios.     Courtesy     Emerson 
Radio  and  Phonograph  Corp.  New  York,  N.  Y. 


Emerson  Personal  Radio 
Ivory   Model   508 


WORCESTER  MOULDED  PLASTICS  CO. 

14  HYGEIA  STREET,  WORCESTER  8,  MASS. 
IT  East  42nd  St.,   New  York  IT,  N.  Y. 


ic  answers  io  these  or  any  other 
question  you  may  have  concerning 
plastics  may  be  obtained  by  writing. 


ARNOLD 


liddleneck    Rd.    •     Cr«at     Neck,  N.Y.    •    Phone :  Great  Neck  4054 


SEPTEMBER 


ii.  in  :.f^^f^fSfr  rlllfc-^W^^hn     M 


.     •         * 
,*.    »        » 


Y      *• 


fllll'M 


fiaraactilicali 


to  Aid  Industry-end  You! 


HANDLING  COMPLEX  PROBLEMS  in  the  chemical 
process  industries  makes  many  a  purchasing 
ami  production  executive  wish  he  had  as 
many  extra  hands  as  this  ancient  Hindu  idol 
to  help  him  through—  and  he  hat! 

THEY  ARE  HIS...  and  y*tn-in  the  coopera- 
tion and  assistance  of  chemists,  engineers,  and 
technician!)  on  General  Chemical  Company's 
Technical  and  Engineering  Service  staffs. 
These  experts  arc  well  qualified  l>y  technical 
training  and  by  practical  industry-wide  expe- 
rience to  offer  sound,  constructive  advice  in 
many  ways-whet  her  your  problems  deal  with 


industrial,  scientific  or  agricultural  chemicals. 

THEY  CAN  FURNISH  pertinent  data  on  proper- 
I  i<->.  grades,  and  packaging  of  General  Chemi- 
cal products  .  .  .  advise  on  materials  and 
methods  for  handling  and  storing  them  .  .  . 
consult  on  their  applications  to  your  opera- 
tions,..and  work  with  you  in  the  development 
of  special  chemicals  to  meet  your  individual 
requirements. 

\\  lic-n  "extra  hands"  such  as  these  can  help 
you,  just  phone  or  write  to  the  nearest  General 
Chemical  Company  Sales  and  Technical 
Service  Office  listed  below. 


GENERAL       CHEMICAL       COMPANY 


40   IICTO*    STRUT.    NEW    YORK   4.   N.  V. 

Sulri  j*J  Tnhnicjl  Sfiift  Ofeti:  Albany  •  Atlanta  •  Baltimore  •  Birmingham 
Hmh.n  •  hiiJ/tcport  •  Buffalo  •  Charlotte  •  Chicago  •  Cleveland  •  Denver 
Detroit  •  Houston  •  Kansas  City  •  Lc»  Angeles  •  Minneapolis  •  New  Mxk 
Philadelphia  •  Pittsburgh  •  Providence  •  San  Francisco  •  Seattle  •  St  Louil 

Vf'enalchce  (\\.iOi  )    •    Yakima  (Wash  ) 

In  \kViuonsm    General  Chemical  Vt'ixomin  Corporation.  Milwaukee.  Wij. 

In  C  anada:  The  Nichols  Chemical  Company,  Limited 

Montreal  •  Toronto  •  Vancouver 


S  THE  IDEAL 
SIZE  FOR  MOST  MOLDING  JOBS! 


rat  H-P-M 

'' 


Ce*:-  * 


Due   to  Its  versatility  In  molding  both 
•mall  and  large   partf  on   a   profitable  basis,  the   H-P-M 
nine    ounce    Infection    machine    is    the    molder's    "production    standard". 

H-P-M's  new  nine  ounce  injection  machine  incorporates  many  im- 
proved operating  features  including  fast  plasticization  with  direct  electric 
heat,  gravity  type  material  feed  and  simplified  electrical  circuit.  Speed  of 
each  reciprocating  machine  member  has  been  greatly  Increased,  resulting 
in  materially  lowering  overall  cycle  time. 

The  H-P-M  nine  ounce  injection  machine  is  a  completely  integrated 
unit.  In  addition  to  the  major  machine  members,  all  hydraulic  pumps, 
valves,  and  controls  are  designed  and  built  by 
H-P-M.  Undivided  responsibility  to  the  user  Is 
thereby  guaranteed.  Investigate  the  outstanding 
production  features  of  this  new  H-P-M  nine  ounce 
"all-hydraulic"  unit.  Write  today  on  your  company 
letterhead  for  a  free  copy  of  H-P-M  Bulletin  45O3 
describing  this  versatile  9  oz.  molding  machine. 

THE   HYDRAULIC    PRESS   MFG.    COMPANY 
Mount  Gilead,  Ohio,  U.  S.  A. 

tr.ncli  oMU.i  If.  N.w  Y.rk,    rhllod.lpl.io.    Cl.v.lor.<l.    Cin<li>»«tv 
D.lrolt    .nJ    Chl<«g».      t .pf.l.nloliv.l    !«   «>h«r   frUtlp.!   CIH««. 


JECTION  MACHINES 

R     MOLDING     THERA10-PLAST/CS 

.cvm  HTIONI7ING    PRODUCTION    WITH     HYDRAULICS    SINCE    1877 


September,   1  946 


plastics 


in  this  issue 


Protect  and  Preserve  with  Coatings Jark  />.  Siratttm  21 

How  Plastics  Components  Make  Better  Products.  . .  .John  IMmimif  21 

.1    K;il>rir*   Marki-t J.   F.   .\ it-hull  32 

-^i n-i-ni-d  Acrylics !/<•/  A/cyers  37 

^  our  Resin  Fibers Hilton  H.  At  lax  and  Robt-rt  S.  Aries  38 

lii-l'l.ini   Mi)l<lin<:  F.\pi-dite)>  Auto  Parts Hrrht-rt  C.hasf  \- 

A  New  Deal  for  Card  Players M.  I..  I'tni-n  50 

Plastics  "Franks"  Are  Edible »  .  R.  Ht-mrich  54 

Training  Seats  Use  Plastics Louix  I.iulu-if  60 

\  in\  I   In-ul. in. in   Produces  Better  Wiring O.  E.  l.ifnbiir/i  63 

"Built-in"    Hinges 67 

( iiuiipn-oiiiii  Mold  Di-i^n.  I'iirl  1 John  (,.  Rttbb  (>'» 

Molded  Circuit  Breaker  Parte 73 

^••.iiiili-—  Di-|il.i\    1-c.riii-  M.ikr    I  li.-ir  Dcliiil 7!! 

Make  Your  Own  Parting  Agent Richard  Gray  81 

departments 

I'la-in-  in  Perspective 18       Engineering   New*   Letter 83 

On  the  Drifting  Board 49       Plaslica    Overneas 85 

PUslirt  it   Work 58       Industry  Highlight* 87 

What1.  New  in   1'1.,-n.  - 74       People   90 

Literature    Re\irw 77       Problem*-  in  Plastics 96 

-i.,i,-i.,.il   Data 82       Association   Activities 97 

The  Plaotirs  Library 99 


COPYRIGHT,    1944 


ZIFF-DAVIS  PUBLISHING  COMPANY 


Hitori.l  Offieei.    ISS  N.  W.beih  Ave.,  Chicago   I.   III. 


WILLIAM  1.  ZHT 
PnUiiktr 


1.  O.  DATB 
/./.«. 


HOMAN    H.     BOUJH 
An  Dirtcttr 

H    G.  STRONG 
i  irfmiaittm    Director 


C.   I.    T1GHE 
Asi't.  If  PnUuktr 

GEORGE  BZIINE1 
Advertising  Director 

H     J.    MORGANXOm 
Production  Director 


VOLUME  5,  NUMBER  3 

tDIJOHIAL     STAFF 


MICHAEL  H.  FROELICH 

Editor 

WILLIAM  SCHACK 

Held  Editor 

V.  E.  GIBBENS 

Associate  Editor 

H.  CHURCH 

Associate  Editor 

LIL  A  SHAFFER 

Associate   i 

GAITHER  UTrRELL 

U'esl  Coast  Editor 

FRED  HAMUN 

M '  .ishttigton  Editor 

CHARLES   A.  SCOGLAND 

Consulting  Technical  Editor 

WALTER  STEINHARD 

Staff  I'kotoyrapkfr 

ARTHUR  E.  H AUG 

Staff  Photographer 

SYDNEY  BARKER 

Art  Editor 

ADVERTISING 


JAMES  A.  CERBONE 
Eastern  Advertising  Manager 

ROY  E.  UNDER 
Uiawest  Advertising  Manager 

WILLIAM  L.  PMNEY 
We  it  err,  Advertising  Manager 

BRANCH      OFFICES 

NEW  YORK  (1) 
Empire  Stale  Bldg.,  Wl  7-0400 

LOS  ANGELES  (14) 
115  5.  Hill  St..  TVcker  9213 

WASHINGTON  (4) 
International  Bldg..  EXEcutive  2592 

TORONTO 
21  Kir,,  Street,  East 


Member 

Audit  lereeu  of 

Circulation* 


COVER 

A  step  in  printing  th» 
lace  tide  on  celluloie 
nilrale  playlnq  card*,  ai 
performed  on  a  "Pott«r" 
Lithographing  pren  at 
th*  Crurer  Mlej.  Co. 
Photo  by  Arthur  E.  Hauq 


Other  Z.«-Devi»  Public.  lion.:  Hying.  Populer  Photography.   R.dio  Newt.   Redio-Electronic   Engineerlnq. 


ri..\STiCS 


SKITEMBKR  1946 


e*t 


. . .  CUT  DOWNTIME  AND 
REJECTS.   .OR  ELSE!" 


I  HAD  WRITTfH: 


Mr.  D.  M.  Whitney,  President 
John  Doe  Plywood  Company 
New  York,  New  York 

Dear  Chief: 

Our  problem  is  resins.  We  don't  seem  to 
be  able  to  get  resins  that  will  function  suc- 
cessfully and  uniformly  within  given 
ranges  of  operating  variables.  We  have  to 
"re-adjust"  resin  for  every  run.  Then  re- 
sults are  not  dependable.  Will  continue 
experimenting  with  resins  and  work  on  get- 
ting speedier  re-adjustments. 


J.  T.  Bailey 
Superintendent 


J.  T.  Bailey,  Superintendent, 

Plant  3 

John  Doe  Plywood  Company 
Portland,  Oregon 


Dear  Bailey: 


Don't   "Dear  Chief"   me.    Cut  downtime 
and   rejects  -  or  else!    I  hold  you  respon- 
sible  for  production  and  product  quality. 
Have  you  never  heard  of  specification 
resins? 


Cordially  yours, 


...and  that's  where  Interlake  comes  in! 


JUST  as  Interlake  has  developed 
specification  resins  (together  with 
necessary  non-deteriorating 
catalysts)  that  perform  uniformly  and 
dependably  for  the  plywood  industry— 
so,   in  many  other  fields,   Interlake 
Specification  Resins  have  eliminated 
resin  "adjusting",  cut  costs,  and 
speeded  production. 

BRING  YOUR  RESIN  PROBLEMS  TO  INTER- 
LAKE, draw  freely  upon  the  wide  ex- 
perience of  our  research  staff.  We  will 
gladly  work  with  you  on  any  resin 
problem,  or  discuss  with  you  the  pos- 


sible  advantage  of  using  resins  in  any 
operation  or  process.  Write  Interlake 
Chemical  Corporation,  Plastics  Divi- 
sion, 1935  Union  Commerce  Build- 
ing, Cleveland  14,  Ohio. 


D.   M.   Whitney 
President 


2500  SQUARE  FEET  IN  ONE  SHEET! 

PHOTO  ABOVE  shows  50  foot  long  ply- 
wood sheet  fabricated  by  Washington 
Veneer  Company,  Olytnpia,  Wash. 
Used  in  building  boats  and  houses. 


INTERLAKE 

CHEMICAL 

Corporation 

•PRODUCTS     FROM     COAL- 


SEPTEMBER  1846 


PLASTICS 


You  get  bigger  output  per  machine 
with  the  new  Defiance  Plastic  Pre- 
form Press — in  two  ways!  (1)  It's 
built  for  high  speed  production; 
and  (2)  it  greatly  reduces  down- 
time! For  example,  die  and  color 
changes  c.in  be  made  in  30  minutes 
— not  4  or  $  hours.  And  density 
and  fill  can  be  quickly  adjusted 
without  interrupting  operation  of 
the  machine. 

There  are  many  more  practical, 
cost-reducing  Defiance  features — designed  by  plastics 
engineers  Jor  the  plastics  industry.  Wide  range  of  shapes 
and  sizes  .  .  .  Uniformity  of  weight  and  density  cuts 
down  molding  rejects  and  assures  small  flash,  less  han- 
dling and  filing,  30  gram  preforms  are  being  made  with 
less  than  plus  or  minus  1 


^  .iriation  . . .  Large  die  space 


for  irregular  or  multiple  dies  .  .  .  Easy  to  clean  .  .  .  All 
lubricated  parts  enclosed  and  below  die  surface  insur- 
ing better  lubrication  and  eliminating  wear.  Preform 
spoilage  due  to  oil  contamination  is  eliminated.  Write 
for  latest  bulletins.  Defiance  Machine  Works,  Inc., 
Defiance,  Ohio. 


DEFIANCE 


PMST/C 


PRZfS 


I'LASTK  * 


SKI'TKMHKK    I'M* 


NO 


V 


HERE'S  A   BRIGHT  FUTURE  FOR   PLASTICS 


FLUORESCENT  lighting  and  plastics  were  made  for  each  other. 
They  just  had  to  get  together. 

See  what  plastics  do  for  this  fine  fluorescent  fixture  by  the 
F.  W.  Wakefield  Brass  Company.  General  Electric  molds  the 
reflectors  and  endcaps  of  urea  plastics.  Transmission  and  re- 
flection characteristics  were  specified  to  produce  cool,  glare- 
free  illumination  that  is  as  easy  on  the  eyes  as  daylight. 

And  these  plastics  fluorescent  accessories  are  precision  parts 
with  interchangeability  for  ready  assembly  into  a  continuous 
line  of  lighting  units.  Light  in  weight, 
strong,  non-shattering— they  reduce  ship- 
ping costs  ...  And  they  make  the  finished 
fixture  safe  and  easy  to  keepclean. 

This  is  just  one  of  many  plastics-for- 
lighting  jobs  by  General  Electric's  com- 
plete plastics  service.  Bring  any  plastics 
problem  to  General  Electric— the  world's 
largest  manufacturer  of  finished  plastics 
products.  Write  to  Plastics  Divisions, 


Chemical  Department,  General  Electric  Company,  1  Plastics 
Avenue,  Pittsfield,  Massachusetts.  You  may  a.vfc  for  the  new 
illustrated  booklet,  "  What  Are  Plastics?" 

G-E  Complete  Service  —  Everything  in  Plastics 

Backed  by  52  years  of  experience.  We've  been  designing  and  manu- 
facturing plastics  products  ever  since  1894.  G-E  Research  works  continu- 
ally to  develop  new  materials,  new  processes,  new  applications. 

No.  1  Plastics  Avenue~ complete  plastics  service-engineering,  design 
and  mold-making.  Our  own  industrial  de- 
signers and  engineers,  working  together,  cre- 
ate plastics  parts  that  are  both  scientifically 
sound  and  good-looking.  Our  own  loolrooms 
are  manned  by  skilled  craftsmen — average 
precision  mold  experience,  12  years. 

All  types  of  plastics.  Facilities  for  com- 
pression, injection,  transfer  and  cold  molding 
.  .  .  for  both  high  and  low  pressure  laminat- 
ing .  .  .  for  fabricating.  And  G-E  Quality 
Control — a  byword  in  industry — means  as 
many  as  160  inspections  and  analyses  for  a 
single  plastic  part. 


GENERAL®  ELECTRIC 

^ii^^'  C0«»-«l^ 

General  Electric  plastics  factories  are  located  in  fort  Wayne,  Ind.,  Meriden,  Conn.,  Scranton,  Pa.,  Taunton,  West  Lynn,  and  Pittsfield,  Mass. 

SEPTEMBER  1946  PLASTICS  7 


_ 


J   tke    I  let    Cva/nJ   ^Jhat  interest  Ljou  .  . 


Wk 


i  en 


GERING 


tk 


ervmq  .  .  . 

a 


And  Service  with  intelligent,  coordinated  headworlc  gives  far  more 
for  your  money  in  revitalized  powders — comparable  to  prime.  The 
dollar-waste  in  plastic  waste,  improperly  treated,  or  imperfectly 
"cured"  is  avoided  by  GP  methods. 

There's  more  than  just  sorting,  cleaning, 
grinding  and  de-metalizing  required  in 
eworking  of  plastic.   Your  "net 


prces  .  .  . 
Telephone:   CRanford  6-2900 


8 


i-H  oj     lll(i(/ic  in  '  C/irrftio/j/rix/ir 
PLASTICS 


conrcrston 


SKPTKMI5KR   1946 


'^^M^^^^m 


£3 


Guns,  Charms,  Trade  Mark  Replicas,  Buttons, 
Novelties  of  all  kinds  and  shapes  can  be 
gold  or  silver  Metaplated  at  low  cost  .  .  . 
Metaplating  makes  jewels  out  of  common- 
place looking  items  .  .  .  Bring  your  premium 
ideas  to  Metaplast,  whose  engineers  will 
show  you  how  they  can  be  Metaplated  to 
meet  the  requirements  of  budget  and  beauty. 


COMPANY  INC. 


205  W.  1 9th  ST.,  N.  Y.  II.N.Y. 

ENGLAND  •  FRANCE  •  CANADA  •  ARGENTINA  •  BRAZIL  •  AUSTRALIA 


METAL        PLATING        ON        PLASTICS 


SEPTEMBER  1946 


PLASTi €S 


Come  See  What  Goes  On 
Under  Our  Roof! 

Introducing  BONNY  BOONTON!    Darling  of  our  plant  — 
incorrigible  scamp! 

Always  getting  into  mischief,  hut  this  time  Bonny's  promised  to 
be  on  best  behavior.    And  she's  volunteered  to  show  you 
through  our  plant.   That  is,  of  course,  if  you  can't  manage  a 
trip  out  to  Boonton  for  a  personal  visit. 

Showing  you  what  goes  on  at  Boonton  is  something  we've 
wanted  to  do  for  a  long  time.    But  war  restrictions  and 
reconversion  interfered.    So,  we  just  had  to  put  it  off  'til  now. 
At  Boonton  we  have  some  new  equipment  that  should 
interest  you  —  some  of  it  acquired  during  the  war  —  some 
since  — some  we  even  designed  and  made  ourselves! 
So,  if  you  are  a  user  or  prospective  user  of  molded  plastics, 
come  on  out  —  or  put  yourself  in  Bonny's  hands. 


Did  you  know  that  we  also 
have  an  interesting  -omul  film 
in  eolor  —  showing  plastic 
molded  the  Boonton  way — at 
Boonton?  Well,  we  have! 
You  can  see  it  liy  dropping 
in  at  our  New  York  City 
office,  122  East  42nd  Street. 
Or  you  can  arrange  to  borrow 
the  film  —  to  show  it  to  your 
own  company  group. 


_  f 


BOONTON  MOLDING  COMPANY 

MOLDERS  OF  MOST  PLASTICS  BY  MOST  METHODS 


FOR  OVER  25  YEARS 
CUSTOM  ENGINEERS 
OF  MOLDED  PLASTICS 

•HHMHBBBMHBI 
10 


122  EAST  42nd  ST.,  NEW  YORK  17  •  ^SS^ 

- FACTORY— BOONTON.  New  Jersey 


SKITKMHKR   I'M  6 


definitely 

+S  TO   COMPETE   IN   PLASTICS 

you  need  the 


- 


today  I 


Oven  (left)  and  press  (right)  mounted 
on  new  2'/2   kilowatt  Thermatron. 


RADIO  RECEPTOR  CO.,  INC.,  Dep'f.T-1 1 
25 J  West  19th  St.,  New  York  1 1,  N.  Y. 

Without  obligation,  send  my  free  copy  of 
"Electronic  Heating  &  Sealing  With  the 
JHERMATRON"  by  return  mail. 

Name 


Company  ______ 


Cify. 


DO  YOU  KNOW- 
HOW  can  you  get  air-tight,  water-tight  seams— 
stronger  than  the  thermoplastic  material  itself — 
in  raincoats,  shower  curtains,  beach  toys,  food 
protectors,  shoes,  handbags  ...  in  hundreds 
of  other  fabricated  plastic  products? 

How  can  you  eliminate  stitching,  resistance 
heating,  or  the  use  of  adhesives  and  solvents  . . ., 
and  still  get  a  product  with  increased  tensile 
strength?  In  plastic  molding,  how  can  you 
decrease  curing  cycle  by  50  to  75%? 

How  can  you  bond  dissimilar  materials  most 
successfully— zippers  to  vinyl  film,  for  instance? 

How  can  you  accomplish  all  these  objectives  at 
reasonable  cost . .  .  and  without  highly  trained, 
highly  paid  operators? 

The  answers  to  these  and  many  other  questions  are 
found  in  our  new  8-page  booklet  "Electronic  Heating 
&  Sealing  with  the  THERM  AT  RON" 

This  new  attractively  illustrated  bulletin  describes 
THERMATRON  units  in  detail  and  gives  examples  of 
specific  application  in  preheating,  sealing,  and  bonding. 
It  answers  scores  of  other  questions,  too,  that 
competition-wise  producers  of  plastic,  plywood  and 
rubber  products  are  vitally  concerned  with  today. 

THERMATRON  heating  and  sealing  units  have  already 
made  hundreds  of  profitable,  fast-selling  new 

products  possible  for  plastics  manufacturers.  Every 
THERMATRON  unit  is  guaranteed  and  serviced. 
Find  out  what  the  THERMATRON  CAN  DO  FOR 
YOU.  Write  today  for  your  copy  of  "Electronic 
Heating  &  Sealing  with  the  THERMATRON". 


DIVISION 


RADIO  RECEPTOR  COMPANY,  INC. 

Since  1922  in  Radio  and  Electronics 
25  1  West  1  9th  Street  j£$\  New  York  1  1  ,  N.  Y. 


Midweit  Sales:  Zephyr  Electronics,  Chicago,   Ml. 


SEPTEMBER  1946 


PLASTICS 


11 


This  is  the  animated  Cruver 
Washable  Plastic  Playing 
Card  display — seen  by  thou- 
sands at  the  New  York  Plastics 
Exposition. 

After  sixty  hours  ot  re- 
peated submergings  the  cards 
on  this  display  were  in  perfect 
condition. 


A  treasure  you  will  enjoy  snar- 
ing   with    friends    lor   tnere    is 
liner   in    playing    cards 

than  CRUVER  WASHABLE 
PLASTIC  PLAYING  CARDS. 


OUR  50TE  TEAR  IN  PLASTICS 

ruver 

WASHABLE  PLASTIC  PLAYING  CARDS 


2456  W.  Jackson  Blvd.,  Chicago,  III.,  Seeley  1300 
New  York  -  2  W.  46th  Si.  •  Wisconsin  7-8847 


f*f,.t*Tf 


SKl'TKMHKR  1946 


We're  proud  of  our  old-timers 
at  General  Industries.  Not  just 
because  of  their  collective  358 
years  of  plastics  molding  experience;  but  mainly 
because  they've  applied  their  wisdom  to  the 
modern  methods  of  today  Result  .  .  .  molded 
plastics  that  attain  the  hallmark  of  quality  plus. 
Naturally,  we're  always  alert  for  every  new 
scientific  or  mechanical  development  that  means 
better  results  for  our  customers.  Examples  .  .  . 
the  addition  of  heatronics  to  our  plastics  molding 
operation — the  use  of  the  finest  and  latest  mold 
making  equipment  and  the  employment  of  in- 


fallible scientific  testing  instruments.  But  we 
temper  our  youthful  enthusiasm  with  these  men 
of  age  and  experience  who  tell  us  whether  or  not 
new  methods  or  machines  will  help  us  make  your 
plastics  molded  job  better  or  less  costly. 

It  gives  us  a  great  feeling  to  know  we've  got 
our  wise  old-timers  on  which  to  depend,  and  we 
know  you'll  get  great  satisfaction  and  realize 
dividends  from  the  knowledge  that  these  years 
of  wisdom  are  back  of  your  finished  product. 
Consult  our  skill  and  experience  on  your  pfastics 
molding  problems. 


™«  GENERAL 
INDUSTRIES  «>. 


D  E  P  T.        P 


E  L  Y  R   I   A 


OHIO 


SEPTEMBER  1946 


PLASTICS 


13 


...  THE  FINAL  TOUCH  OF  PERFECTION  THAT 
MAKES  PLASTICS  SELL  FASTER! 


Plastics  look  their  best,  and  sell  fastest,  when 
they  have  the  added  surface  beauty  of  a  very  fine 
finish  like  CODUR. 

CODUR  is  a  line  of  high-gloss,  synthetic  baking 
enamels  especially  designed  for  a  one-spray  coat 
application  on  molded  (phenol  formaldehyde) 
plastics.  They  have  excellent  color  retention  and 
bake  to  a  very  hard  mar-resistant  surface.  CODUR 
is  available  in  most  colors  in  plain  enamels  and 
many  metallic  colors.  M  &  W  also  offers  air-drying 
or  baking  finishes  for  other  plastics:  acetates,  buty- 
rates,  methacrylates  and  others. 


SERVICE  THROUGH 
RESEARCH   AND   EXPERIENCE 

Whatever  the  material,  sim- 
ply submit  a  sample  of  your 
plastic  and  we'll  recom- 
mend the  proper  finish.  70 
years'  experience  and  our 
fine  research  facilities  are 
at  your  service.  Contact  any 
of  our  offices. 


riONECIS   \ M.&WC?/      I*  PiOTICIION 

-*  


MAAS  fcVWALDSTilN  COMPANY 


NEWAIK  4, 
NEW  JERSEY 
1658  Carroll  Ave.,  Chicago  12       •       6  Jersey  St.,  Boston  15       -        1228  W.  Pico  Blvd.,  Los  Angeles  15 

PRODUCERS  OF  LACQUERS,  ENAMELS,  SYNTHETICS  AND  SPECIAL  PRODUCTION  FINISHES 
14  PI.  1ST  II  -ft  SKI'TKMHKR 


THE 


CHAMP 


Heats  6  Pounds  (96  ozs.)  in  ONE  MINUTE 


Whenever  you  see  the  THERMALL  Diamond  on  an 
HF  Heating  Unit,  you  can  bet  your  last  dollar  on 
the  ufmott  in  performance. 

We'll  gladly  give  you  technical  and  engineering 
data  about  every  size  THERMALL  Unit  Users  say 
that  we  are  conservative  in  our  power  ratings. 
They  tell  us  that  THERMALL  HF  Heating  Units 
consistently  deliver  more  than  rated  power;  preheat 
faster  than  we  claim. 

Time  after  time,  users  have  said  they  were  "amazed 
at  THERMALL  performance." 

If  you  have  a  pre-heating  or  molding  problem  of 
any  kind  and  want  technical  advice  or  assistance 
— write  us.  We  will  assist  you  by  assigning  one 
at  our  technical  representatives  to  your  problem 
without  obligation. 

When  you  want  a  job  done  day  in — day  out  re- 
member that 

THERMALL  means  PERFORMANCE 


IHIIKIU  IMIIULL  Ilimu 

Horntt  flonfom  Chomp 


The  THERMALL  Champ  occupies  only 
20x30  incheu  oi  your  floor  space.  Heats 
96  ounces  compound  to  molding  temper- 
ature In  1  minute.  Completely  portable. 

Bulletin  S   gives  specifications   and  details  oi 
all  THERMALL  HF  Units.     It's  free,  on  request. 

W.      T.      LA      ROSE      &      ASSOCIATES 

635  Second  Avenue  Troy,  New  York 

Repreientative*  In  All  Principal  Cities 
Export:  Omni  Products  Corp.,  40  East  34th  St.,   New  York   16.   N.  Y. 


SEPTEMBER  1946 


PLASTiCS 


15 


Wotertown,  this  it  a  daily  occurrence— taking  pictures,  we  mean.  Every  product  "MOLDED  BY  WATER- 
TOWN"  it  put  through  that  final  tetf,  the  X-ray.  This  enables  us  to  be  sure  that  your  molded  parts  are 
properly  cured;  that  inserts  are  solidly  imbedded;  in  short— that  your  product  is  "molded  right". 

We  maintain  complete  laboratory  facilities  .  .  .  Impact  and  Tensile  strength  testing  equipment— special 
ovens— blending  machines.  Each  individual  product   receives  the  full  benefit  of  this  complete  service. 

•    THI       WATERTOWN       MANUFACTURING       COMPANY,      WATERTOWN,      CONNECTICUT 

i  — N»w  York,  CUr.lond,  D«lro;l,  Chicago,  Milwouk**,  Son  Froncnco 


16 


I' I.  .\STICS 


SKITKMKKR  1946 


A  New  Plastics  Injection  Press  for 
Easy-Fast-Profitable  Production 


FEATURES  OF 


FOR 
FREE  FOLDER 

which  illustrates  and 
describes  the  Van 
Dorn  Plastics  In- 
jection Press  and  its 
applications. 


PRESS 

1  OZ.  CAPACITY 
POWERED  FOR  PRODUCTION 
AUTOMATIC  PARTS  EJECTOR 
AUTOMATIC  TEMPERATURE  CONTROL 
LOW  COST 


THE    VAN     DORN     IRON    WORKS    CO. 


2683   EAST    79  TH    STREET 


CLEVELAND    4 


SEPTEMBER  1946 


I'LASTiCS 


17 


PLASTICS 


NEW  OPA  ceilings  on  plastics  products  went  into  effect 
on  July  27,  the  revisions  granting  an  11%  price 
increase  for  plastics  goods  having  list  or  established  prices. 
and  a  4'  '2%  increase  for  plastics  goods  priced  by  formula. 

The  industry  relief  appeal  instituted  by  SPI  and  the 
Plastics  Industry  Advisory  Committee  following  an  in- 
dustry-wide survey  of  companies  producing  plastics  prod- 
ucts was  influential  in  bringing  about  price  relief.  Results 
of  the  inquiry,  according  to  OPA,  indicated  that  price 
increases  were  required  to  stimulate  production  to  meet 
the  growing  demand  for  plastics  products. 

Where  a  price  adjustment  is  made  under  terms  of  the 
amendment,  the  manufacturer  should  inform  the  cus- 
tomer of  the  authority  for  the  adjustment,  namely  Amend- 
ment 3  to  MPR  523,  effective  July  27,  1946. 


PLUS  new  ceilings,  the  OPA,  by  Amendment  33  to 
S.  O.  1 29,  has  removed  plastics  buttons,  plastics  bath- 
room fixtures  and  accessories,  plastics  kitchenware,  and 
plastics  poultry  leg  bands  from  price  control.  With  the 
new  power  of  industry  advisory  committees,  the  plastics 
industry  may  he  hopeful  of  additions  to  the  above  list. 
How  wisrly  the  industry  institutes  changes  in  prices  on  the 
items  no  longer  under  ceilings  may  have  much  to  do  with 
the  speed  of  "decontrol 


RKPOKTS  of  plastics  houses  in  Germany,  of  plastics 
boats  and  automobiles  in  England  ("Plastics  Over- 
seas,' p/osfici,  August,  1946),  and  of  other  forward 
steps  in  these  two  countries  constitute  a  challenge  to  the 
American  industry  to  keep  on  its  toes.  We  must  not  be 
afraid  to  experiment,  and  we  must  occasionally  loose  the 
bird  in  the  hand  to  try  for  the  two  in  the  bush. 

We  think  that  in  the  past  year  we  have  detected  an 
untypically-American  fear  on  the  part  of  some  industries 
to  let  its  brighter  and  more  creative  minds  apply  their 
imagination  to  the  development  of  new  products.  They 
are  being  kept  at  work  on  matters  of  the  moment  instead 
of  being  allowed  to  strike  out  in  new  directions. 

There  is  danger  in  such  fear,  and  if  it  is  allowed  to 
restrict  the  pioneering  spirit,  which  has  done  much  to  put 
us  where  we  are  technologically,  scientific  progress  in 
our  country  may  be  overshadowed  by  technical  advance- 
ment abroad. 


iinu  tomes  a  time  to  all  companies  when  they  must 
choose  whether  to  concentrate  their  research  abilities 


and  facilities  on  present  problems  or  on  long-range 
projects.  This  choice  must  not  be  lightly  made.  Too 
often  future  welfare  is  sacrificed  to  present  profit. 

It  is  hard  for  the  executive  in  the  home  office  to  see 
the  advisability  of  keeping  a  man  on  a  long-range  piece 
of  research,  the  results  of  which  may  not  be  manifest  for 
years,  when  using  him  on  current  problems  would  expedite 
their  solution  and  bring  about  an  immediate  rise  in  sales, 
but  the  former  course  often  turns  out  to  be  more  profitable 
in  the  end. 

Without  fundamental  study  and  long-range  experimen- 
tation, a  business  runs  the  risk  of  "drying  up  on  the  vine." 


Tin.  ASTM  nomenclature  and  definition  committee — 
to  be  exact.  ASTM  Subcommittee  10,  D-20— is  said 
to  be  considering  the  following  definition  for  a  plastics  or 
organic  plastics:  "A  plastic  is  any  one  of  a  large  and 
varied  group  of  materials  which  consists  of  or  contains  as 
an  essential  ingredient  an  organic  substance  of  large 
molecular  weight,  and  which,  while  solid  in  the  finished 
state,  at  some  stage  in  its  manufacture  has  been  or  can  be 
formed  (cast,  calendered,  extruded,  molded,  etc.)  into  vari- 
ous shapes  by  flow,  usually  through  the  application,  singly 
or  together,  of  heat  and  pressure." 

This  was  a  good  definition  when  it  appeared  in  a  United 
States  Tariff  Commission  report  in  1938,  it  is  still  a  good 
definition,  and  we  recommend  it  almost  unreservedly  to 
ASTM  Subcommittee  10.  D-20. 


IN  THK  above  definition,  we  would  say:  .4  plastics  is, 
not  .1  plastic  is,  in  the  belief  that  plastk  should  be 
limited  in  use  as  an  adjective  meaning  pliable  or  moldable. 
To  illustrate  further,  we  would  say:  A  piece  of  plastics 
may  be  plastic  or  it  may  be  rigid. 

Some  people  have  objected  to  plastics  followed  by  is. 
Do  they  also  object  to  economics,  mathematics,  and 
trumps  followed  by  H? 


Nun  .i|iro|Hi.s  of  what  we  have  been  saying  on  this 
page  of  the  need  for  non-flammable  building  ma- 
terials; The  recent  ferry  terminal  fire  in  New  York 
o(  c  urred  while  .in  organization  of  fire  chiefs  was  in  con- 
vention in  the  city.  and.  needless  to  say,  the  chiefs  broke 
u|>  the  session  to  go  to  the  fire.  In  a  later  session,  one  of 
the  officials  of  the  organization  charged  that  the  I'nited 
Nates  was  the  "world's  No.  I  firetrap." 


I- 


ff.  \STH  * 


SKITK.MKKR  1946 


Fhe  Heats      Still  On... 


26  years  later! 


In  1920,  Kurz-Kasch  engineers  worked 
out  the  notion  of  pre-heating  plastic  materials  before  plac- 
ing them  in  the  press.  Because  of  the  reduction  of  molding 
time  and  improvement  in  moldings  so  handled,  this 
technique  quickly  became  standard  practice. 


w.. 


ant  to  reap  advantages  today  from  some  of  tomorrow's 
bright  ideas  for  molding  plastics? 

This  series  of  ads  shows  how  Kurz-Kasch  customers  have  done 
exactly  that — for  many  standard  molding  practices  of  today  evolved 
from  ideas  worked  out  by  our  engineers  to  speed  and  improve  the 
production  of  their  parts. 

It  pays  dividends  when  your  plastic  production  benefits  first  from 
such  ideas.  Let  us  tell  you  about  Kurz-Kasch  molding  facilities — send 
today  for  your  copy  of  our  free  booklet,  "A  Businessman's  Guide  to 
the  Molding  of  Plastics." 

Kurz-Kasch 


For  Over  29  Years 

Planners  and  Molders  in  Plastics 


Kurz-Kasch,  Inc.,  1413  S.  Broadway,  Dayton  1,  Ohio.  Export  Offices:  89  Broad  Street,  New  York,  N.  Y. 
Branch  Sales  Offices:  New  York  •  Chicago  •  Detroit  •  Los  Angeles  •  Dallas  •  St.  Louis  •  Toronto,  Canada. 

SEPTEMBER  1946  PLASTICS 


19 


WHITHIK       YOU     NfID 


Hose  Nozzle  Connection  for  tank-type 
vacuum  cleaner.  Four  plastic  pieces 
(shown  above  separately  and  as  a  unit) 
are  molded  to  assemble  with  hose  ond 
spring  dips  for  quick,  easy,  air-tight 
connection. 


rot  mermen  *miMtii 


OMICI  MACumts  o»  mmtrtui  lauiwunT 


IMIIOOM  fllTWU  XS.  MltKM.  MCUimilt^V, 


•  -—•    ; 


Here's  a  step  ahead  in  parts  production  in  plastics  ...  in 
product  beauty  and  utility  ...  in  manufacturing  efficiency  and 
economy.  This  nozzle  assembly  for  a  new  vacuum  cleaner  sug- 
gests to  you  what  Amos  can  do  in  making  your  own  product- 
planning  a  precise  reality. 

Exactness  in  size  ...  in  fit  ...  in  tolerances  .  .  .  yes!  Amos  die 
making  is  right!  Underscore  that  point  for  your  own  advantage. 
Then  add  the  fact  of  flawless  molding  and  the  accuracy  of 
Amos  finishing,  and  decide  to  call  Amos  for  that  "step  ahead" 
you  want  in  your  own  new  products. 

From  engineering  to  finishing  Amos  does  a  complete  job  .  .  . 
and  does  it  right.  Just  send  us  your  drawings  or  write  us  what 
you  have  in  mind  to  be  molded  in  plastics. 

AMOS    MOLDED    PLASTICS,    EDINBURGH,    INDIANA 

Division    of    Amos  -  Thorn  pion     Corporation 
One  of  rne  Mo,l  Modern  Hailic  Molding  P/onli  in  rhe  fnduirrv 


20 


SKITKMHER  ISIfi 


jL ct    2).  Stratton 


MAN  is  forever  at  war  to  prevent  the  deterioration 
and  destruction  of  his  belongings.  He  not  only 
struggles  against  the  normal  hazards  of  use  and  wear  but 
against  such  natural  forces  as  the  rain  and  the  sunshine, 
which — indispensable  as  they  are — do  not  bestow  an  un- 
alloyed blessing. 

In  this  phase  of  his  existence,  he  has  achieved  marked 
success  in  recent  years  with  the  development  of  improved 
plastics  coverings  and  coatings,  and  his  accomplishments 
appear  to  be  only  beginning. 

Plastics  protective  films  for  woods  and  metals  have  shown 
that  when  rightly  compounded  they  will  outlast  oil  paints 
by  many  years.  Besides  preventing  moisture  absorption, 
many  of  these  guard  against  abrasion,  salt  spray,  ultra- 
violet ray,  flame,  chemicals,  fungus,  insects,  and  other  de- 
teriorating influences. 

Textile  and  wood  impregnations  have  increased  the  sub- 
materials'  endurance,  established  flame  resistance,  height- 
ened natural  colors,  added  to  cleanability,  and,  in  general, 
have  qualified  both  fabrics  and  timber  for  greater  per- 
formances. 


SEPTEMBER  1946 


21 


Shin  impregnated  with  "Chemosize"  requires  no  starching.  Crease  in  collar  is  permanent:  while  nigh 
melting  point  of  coating  prevents  cloth  from  sticking  to  iron,  a  tendency  of  some  untreated  fabrics 


Production  of  this  type  calls  for  "know  how"  on  the  part 
of  the  organic  chemist  He  must  understand  basic  plastics 
materials,  film  formers,  impregnators,  plasticizers,  catalysts, 
modifiers,  fillers,  expanders,  elastomers,  inhibitors,  fungi- 
cides, pigments,  dyes,  waxes,  solvents  and  dispersing  me- 
diums of  natural  and  synthetic  origin. 

Robert  Ernst,  chief  chemist  of  Eronel  Industries,  Los 
Angeles,  who  has  developed  and  tested  a  large  line  of  coat- 
ings and  impregnations,  approaches  those  problems  with  a 


study  of  the  material  to  be  protected.  Otherwise  poor  bond- 
ing, unsatisfactory  penetration  and  undesirable  chemical  re- 
action between  protected  and  protecting  materials  may  be 
anticipated. 

For  instance,  care  must  be  taken  with  each  metal  and 
types  of  the  same  metal  to  insure  that  oxidation,  auto-oxida- 
tion, sensitivity  of  coatings  to  catalytic  metals  like  iron  and 
/inc.  actinic  ray  decomposition,  and  similar  reactions  art- 
inhibited. 


Thormodip  .  a  strippable  packaging  coating,  offers  the  valuable  characteristic  of  transparency. 
Illustrations  show  plugs  and  wrenches  with  plastics  coatings  intact  and  In  partially  removed  stages 


22 


Pt..\STI1°fi 


-I  I'TKMKKR  1 9 16 


Coatings  for  woods  particularly  should  be  resistant  tu 
joisture  absorption.  This  is  especially  true  with  trans- 
.arent  coatings  designed  to  bring  out  the  beauty  of  the  grain 
n  timber.  Otherwise  the  transparent  coating  may  blush, 
nd  the  cloudy  effect  thus  induced  would  conceal  rather 
han  reveal  the  grain,  thereby  defeating  one  purpose  for 
vhich  the  clear  film  was  created. 

Methods  of  application  should  be  so  "fool  proof"  that 
wen  a  housewife  may  apply  plastics  coatings  or  impregna- 
ions  in  her  own  home.  Simple  applications  are  advisable 
n  all  cases,  as  workmen  are  inclined  to  disregard  involved 
nstructions.  Likewise  non-toxic  ingredients  should  be  em- 
jloyed.  Workers  will  refuse  to  handle  a  compound  likely 
:o  cause  skin  irritations  or  other  harmful  influences  to  them- 
selves. 

ncreosed    Workability 

Plastics  coatings  and  impregnations  frequently  increase 
lie  workability  of  materials  to  which  they  are  applied.  Ernst 
las  developed  a  colorful,  flexible,  abrasive  resistant  coat- 
ng  for  sheepskin  and  other  fleshy  leathers  which  makes  the 
roduct  more  flexible  and  correspondingly  easier  to  handle, 
ut,  and  fashion.  As  the  coating  is  applied  directly  to  the 
eshy  surface  of  the  skin,  buffing  of  the  hide — which  thins 
nd  weakens  the  leather — is  eliminated. 

Flame  resistance  for  household  and  theater  drapes  as  well 
s  sails  for  ships  is  another  accepted  accomplishment  of  cer- 
ain  plastics  impregnations.    Ernst  recently  conducted  a  test 
n  sail  cloth  impregnated  with  one  of  his  compounds.    Two 
dentical  cloth  sections,  one  impregnated  and  one  natural, 
were  contacted  with  the  flame  of  a  blow  torch.     The  un- 
reated  textile  section  immediately  blazed  and  was  destroyed 
n  35  sec.    The  impregnated  piece  of  canvas  charred,  gave 
no  evidence  of  flammability,  and  was  but  partially  damaged. 
Resistance   to   oils,    greases,   acids,   alkalis,   and   certain 
chemicals  has  been  established  by  a  plastics  compound  to 
impregnate    workmen's    overalls   and   jackets.      Petroleum 
products  adhere  to  the  surface  of  the  cloth,  but  penetration 
of  the  weave  is  inhibited,  a  factor  which  adds  greatly  to 
the  cleanability  of  the  garments. 

Adds   Characteristics 

A  plastics  sizing  for  rugs  created  by  the  same  chemist 
stabilized  the  fiber,  brightened  the  color,  inhibited  penetra- 
tion of  liquids,  and  rendered  the  rug  stationary  on  glossy 
hardwood  floors  by  imparting  a  non-skid  characteristic.  The 
compound,  which  was  flexible,  furnished  th«  effect  of  a 
cushion,  and  the  need  for  a  floor  mat  was  thereby  elim- 
inated. 

A  permanent  sizing  for  washable  fabrics  was  developed 
recently.  Known  as  Chemosize,  it  is  applied  by  submersion, 
quetch,  dyeing  jiggers,  or  laundry  machine  tumblers,  after 
which  it  is  dried  in  the  air.  Simplicity  of  the  application 
warrants  its  being  undertaken  in  the  home.  When  dried, 
no  further  starching  is  required  during  the  usual  life  of  a 
garment. 

Desirable  creases  like  the  fold  of  a  shirt  collar,  once 
pressed  into  shape,  are  established  permanently.  A  high 
melting  point  reduces  the  tendency  of  fabrics  to  adhere  to 
the  iron  or  mangle  and  cause  wrinkles. 

Strippable  packaging,  which  came  into  its  own  during  the 
war,  also  is  making  rapid  advances.  Temporary  plastics 
skins,  removable  like  banana  peels,  are  being  applied  by 
spray  or  submersion  to  machinery  and  tools  for  their  preser- 
vation in  shipment  or  stock  rooms.  Such  coatings  usually 
are  transparent  to  permit  reading  of  labels  and  identifying 
marks.  Many  have  high  tensile  strength  and  are  resistant 
to  moisture,  salt  spray,  violet  ray,  oxidation,  fatigue,  and 
impact.  END 


35-second  fire  teat  shows  plastics-impregnated  canvas  mere- 
ly charred;   untreated   cloth  has  been   virtually   destroyed 


"Thermo-dip "-packaged  steel  escapes  corrosion  alter  10-day 
salt  spray  immersion;  unprotected  piece  is  heavily  corroded 


Uncoated  aircraft  part  shipped  overseas  shows  marked  cor- 
rosion; "Spraypeel"-covered  parts  suffered  no  deterioration 


SEPTEMBER  1946 


PLASTICS 


23 


Plastics  handle  and  (pout  lid  on  tea  kettle  join  with  metal  to  make  a  superior  product 

How  Plastics  Components 
Make  Better  Products 

W  (J  ° 


n 


Till'  role  played  by  plastics  in  conjunction  with  cloth, 
wood,  rubber,  metal,  paper,  and  other  materials  is  often 
overlooked  where  the  attention  is  centered  on  the  results 
accomplished,  rather  than  on  the  material-,  which  made 
them  possible.  These  are  the  hidden  applications  of  plastics, 
where  the  introduction  of  perhaps  only  a  minor  plastics 
component  makes  possible  a  new  quality  of  performance  in 
the  cloth,  wood,  or  paper  which  could  not  possibly  be 
achieved  otherwise. 

These  relatively  "minor"  applications  tuny  actually  mean 
more  from  the  standpoint  of  over-all  volume  than  the 
familiar  molded,  cast  or  laminated  parts,  and  their  encour- 
agement and  recognition  will  do  much  toward  contributing 
to  the  successful  growth  of  plastics.  With  this  thought  in 
mind,  I  would  like  to  scan  briefly  some  of  the  important 
contributions  which  plastics  have  made  to  other  industries. 
generally  in  combination  with  other  materials. 


24 


In  many  industrial  applications,  plastics  and  metals  are 
looked  upon  as  competitive.  In  some  designs  metals  will 
predominate  while  in  others  plastics  are  featured  though 
often  a  combination  of  both  offer  the  consumer  the  optimum 
qualities.  I  do  not  propose  to  engage  in  the  controversial 
subject  of  plastics  versus  metals,  but  rather  to  concentrate 
upon  combinations  of  the  two  which  work  to  mutual  ad- 
vantage. 

For  maximum  strength  in  a  given  thickness,  metal 
superior  to  plastics.  For  appearance,  feel,  and  resistance  to 
electrical  and  thermal  conductivity  the  plastic-  are  superior. 
This  suggests  that  the  Iwsc  substance  may  IK  metal  and  the 
surface  agent  a  plastics  material.  When  the  plastics  ate 
present  as  thin  coating  films,  the  qualities  of  appearance-, 
feel,  and  resistance  to  chemicals  and  electrical  currents 
manifest  themselves.  As  the  plastics  grows  thicker,  which 
may  be  the  case  of  an  extruded  or  molded  application  over 


-I  ITKMHKK    H 


TWO 


MOLDING  Produces  NewTenite  Keys 


Tenite  adding-machine  keys  double- 
injection  molded  by  Electric  Manu- 
facturing Co.  for  Clary  Multiplier  Corp. 


Keys  of  this  adding  machine  are 
double-injection  molded.  Tenite 
of  one  color  is  injected  to  form 
numerals  and  letters;  after  that 
has  hardened,  a  second  color  is 
injected  for  the  body  of  the  key. 
Molded-in  numerals  and  letters 
are  thus  as  permanent  as  the 


color,  which  is  inherent  in  Tenite 
and  cannot  wear  off.  Under  con- 
stant hard  use.  Tenite  keys  re- 
main lustrous,  new-looking,  and 
easy  to  read. 

The  excellent  molding  prop- 
erties of  Tenite  which  adapt  it 
to  this  process  also  make  it  one 
of  the  most  widely  used  mate- 
rials for  injection  molding  and 
continuous  extrusion.  Tenite  is 
formed  into  products  of  many 


sizes  and  shapes  at  the  fastest 
speeds  possible  with  plastics.  It 
comes  from  molds  and  extrusion 
machines  with  a  high  natural 
luster  which  requires  no  polish- 
ing and  a  minimum  of  finishing. 

For  information  about  the 
uses  of  tough,  colorful  Tenite. 
write  to  TENNESSEE  EASTMAN 
CORPORATION  (Subsidiary  oi 
Eastman  Kodak  Company). 
KINGSPORT,  TENNESSEE. 


TENITE  AN   EASTMAN  PLASTIC 


metal,  other  problems  will  arise,  based  upon  the  differences 
in  thermal  expansion  and  the  relative  environmental  insta- 
bility of  some  plastics  compared  to  metals.  Cracked  steering 
wheels  and  glove  compartment  doors  on  cars  are  examples 
of  over-enthusiastic  applications  of  substantial  quantities  of 
plastics  to  metals  without  careful  and  sufficiently  basic 
study.  Today  we  know,  however,  that  the  solution  lit--,  in 
softer,  more  highly  plasticized  varieties  of  thermoplastics 
such  as  cellulose  acetate  butyrate  and  cellulose  propionate. 

Reverting  to  fundamentals,  it  can  be  readily  seen  that  of 
:ill  the  metals,  aluminum  alloys  most  closely  match  the  ther- 
mal expansion  qualities  of  plastics  materials.  That  we  have 
not  seen  a  greater  use  of  aluminum  alloy  in-en-  in  molded 
plastics  is  hard  to  explain.  However,  the  war  has  shown 
us  some  interesting  and  very  stable  combinations  of  tin--.- 
two  materials,  and  in  our  future  efforts  and  designs  we 
should  be  guided  in  this  direction.  Of  course,  the  rate  of  ex- 
pansion, which  is  based  upon  the  thermal  conductivity,  still 
finds  aluminum  alloys  at  great  variance  with  plastic-, 
though  when  heat  transfer  problems  are  not  too  acute,  the 
thermal  coefficient  similarity  of  various  plastics  and  alu- 
minum alloys  should  dictate  more  combinations  of  these  two 
materials.  From  an  esthetic  standpoint  it  is  not  difficult  to 
find  intriguing  combinations  of  aluminum  alloy  and  various 
plastics,  and  there  should  be  more  concerted  effort  in  this 
direction. 

Now  let  us  examine  those  combinations  where  either  the 
pla-tics  or  metals  exist  as  a  discontinuous  phase.  The 
sealing  of  porous  metal  castings  with  the  aid  of  liquid  plas- 
tic- materials  is  not  new,  and  various  thermosetting  pheno- 
lic and  polyester  resins  have  been  employed  for  this 
purpose.  The  problem  requires  the  application  of  a  liquid 
plastics,  convertible  by  heat  or  catalysts  or  both  to  a  solid 

Long  metal  inserts  in  blow  gun  present  problems  ol 
expansion   differences   between   plastics   and   metals 


Plastics  plus  plaster  produces  new  duplicating   pattern 
able  to  withstand  requirements  ol  Pantograph  machines 


after  diffusion  into  the  porous  structure.  If  substanti 
shrinkage  is  involved  in  this  conversion,  a  perfect  job  w 
not  be  realized.  This  is  emphasized,  because  volumetr 
shrinkage  during  polymerization  is  substantial  for  mo 
resins  and  more  work  should  be  done  in  reducing  it.  Hen 
ever,  even  now,  it  is  possible  to  salvage  expensive  castini 
by  the  application  of  sealing  impregnants  of  plastics  mat 
rials,  capable  of  filling  pores. 

Some  years  ago  the  writer  had  occasion  to  review  ai 
report  upon  a  number  of  combinations  of  plastics  wi 
powdered  metals.  The  growing  field  of  powder  metallurj 
may  well  find  unique  possibilities  in  such  combination 
Proven  applications  have  been  felt  already  in  special  loadii 
coils  or  wireless  cores  where  magnetic  materials  must  1 
insulated  (with  plastics)  in  a  manner  designed  to  redw 
eddy  current  losses.  During  the  second  World  War  tl 
development  of  the  T-44  frangible  bullet  was  made  possib 
through  a  combination  of  powdered  lead  and  phenol 
resins.  This  target  practice  bullet  left  a  telltale  mark  < 
the  aluminum  alloy  airplane  surfaces  against  which  it  w: 
fired,  without  penetrating  or  causing  other  damage.  Tl 
bullets  were  largely  transfer  molded.  Special  motor  brush 
carrying  a  high  current  density,  as  in  the  operation  i 
electroplating  generators,  have  been  prepared  from  po\ 
dered  copper  and  a  minor  proportion  of  resin  binders.  The 
are  many  other  examples  which  would  illustrate  the  pob 
that  in  many  unsuspected  applications  plastics  are  playir 
important  roles  in  combinations  with  metals. 

Plastics  Aid  Textiles 

The  contributions  of  plastics  to  the  field  of  textiles  hai 
taken  place  in  two  noteworthy  respects:  formation  < 
basic  fiber,  and  treatment  for  the  natural  fiber.  Materia 
such  as  rayon,  cellulose  acetate,  nylon,  Aralac,  and  othe 
are  synthetic  fibers  used  in  manufacturing  the  comple 
textile  product.  They  should  not  be  underestimated  b 
cause  of  the  word  "synthetic,"  since  these  fibers  are  actual 
superior  in  quality.  The  treatment  of  wool  and  cotton  wi' 
plastics  materials  as  coating,  impregnants,  or  sizing  agen 
is  the  other  important,  though  lesser  known  field.  Crea 
resistant  and  crush  resistant  fabrics  are  almost  10  to  1 
years  old  by  now — though  little  does  the  public  suspect  th 
urea  and  melamine  resins  have  been  employed  for  achievir 
this  result.  More  recently,  the  quality  of  various  coarse  fa 
was  enhanced  through  treatment  with  synthetic  resins.  Tl 
chief  application  of  this  technique  is  in  the  conversion  i 
-.heepskin  to  beaver-like  quality  by  reacting  a  cresol  forms 
dehyde  resin  upon  the  keratin  of  the  protein  fiber.  Bas 
-tudies  of  natural  fibers  have  enabled  us  to  approach  tl 
problem  chemically  as  well  a-  mechanically. 

Considerable  attention  has  been  given  to  the  attainmei 
of  shrink  resistant  textiles  and  water  repellent  finishe-  \vii 
the  aid  of  plastics.  To  accomplish  this,  aqueous  dispersioi 
of  the  synthetic  resin  forming  materials  may  be  employ* 
in  treating  the  natural  occurring  fiber  before  it  is  \\ovt 
into  dress  goods  or  the  like,  or  in  treating  the  finished  to 
tiles.  The  sizing  of  warps  and  all  types  of  yarns  wil 
pla-tics  opens  an  extensive  field.  To  cite  a  few  of  the  man 
tuples,  woolens  impregnated  with  low  concentration-  < 
melamine  formaldehyde  (Rcslooms)  can  be  washed  will 
out  substantial  shrinkage.  Aqueous  dispersions  of  octt 
decylethylene  urea  are  reported  in  waterproof  fabrics.  Ev« 
the  development  of  fabrics  from  cotton,  in  an  unspun  col 
dition,  requires  the  employment  of  synthetic  resins  I 
hinders  for  the  fibers. 

The  polyvinyl  resins  are  prominent  in  the  field  of  thii 
water  repellent  coatings.  Plasticized  polyvinyl  chloride  at 
polyvinyl  butyral  are  featured  in  this  development.  <  Vlli 
lose  ethers  and  "adducts"  of  cyclopentadicne  arc  also  use 
commercially.  These  coatings  are  quite  flexible  and  will  ro 
affect  the  serviceability  of  the  goods  involved.  Grease  an 


26 


SKPTKMHKR  194 


Ckemoco  MOLDING  POWDERS 


MASS  PRODUCTION 


"JL 


m 


In  the  new  postwar 
EVERSHARP  SCHICK  INJECTOR  RAZOR 

By  the  hundreds  of  thousands,  the  famous  Eversharp  Schick 
Injector  Razor  is  once  again  moving  toward  civilian  purchasers. 
Smartly  designed,  this  new  Schick  has  a  beautifully  mottled 
handle  of  Chemaco  Ethyl  Cellulose,  which  is  also  very  pleas- 
ing to  the  touch.  The  color  goes  all  the  way  through.  Combined 
with  beauty  are  toughness  and  durability  . . .  and  a  remarkable 
resistance  to  impact  that  insures  against  accidental  breakage. 
Chemaco  is  proud  to  have  shared  in  developing  mass  produc- 
tion materials  for  this  high  quality  product.  We  shall  be  happy 
to  help  you  solve  your  mass  production  problems.  Our  trained 
laboratory  technicians  and  our  wide  experience  with  Ethyl 
Cellulose,  Cellulose  Acetate  and  Polystyrene  are  at  your  service. 


Ckemaco 


A  subsidiary   of  Manufacturers  Chemical   Corporation 
Berkeley   Heights.    N.   J.     •     Branch  Office  in   Cleveland 


SEPTEMBER  1946 


i'LASTt  CS 


w»if  type  of   ftuor«ten»  lighting  fixture,    mod*    almost   entirely  of 
ur«o-rormold*hyd*    F.  W.  Wakefield  Bra**  Company,  Vermilion,  Ohio. 


Telex  Magnet^  Pillow  Speaker  houting  of  Ptotkon  Molded  Color.   Deiigned  for 
normal  tound  reproduction  wh*n  placed  under  a  pillow,  Telex,  Inc..  St.  Paul,  Minn. 


Pr*tt\mied  connectors  mod*  of 

cellulose  ftll»d  Platkon  m«(amin*  to  *xtr*m«ly  rigid  specification  bvcout* 
of  iii  low  mootvr*  obiorption,  high  volume  and  »urfac*  r«»i>tivtfy,  very  high  arc 
remittance,    *xc*llent   dielectric  propertict  at   low  and  high   frequencies,   impact 

retiifanc*  and  re»ittan<e  to  neat.  tt.  H.  Buggie  &  Company,  Toledo,  Ohio. 


Aircraft  m»t  dilation*  u»ing  Pla*kon— il*  trim  tab  indicator  actuator;  (5:  houting  f  or 
map  reading  light;  3  core  governor  retittor  and  (4)  block  anembly  governor  ter- 
minal, both  u*«d  with  Beech-Roby  propeller.  Beech  Aircraft  Corp.,  Wichita,  Kan. 


*  -..«*•»  fty  rod.  weifhi  »g  •nfy  ?    , 
•  •*,  and  *wa>ple     SK 


».  mode  of  Floikon  Netin  and  gin.* 
Companr,   Kateimerioo,   M"K 


/ 


.  __   _ 

,  d*    beautifully   into  the   fleth   1on«i   of   tKe 

wearer.     Product   of    Zenrth   Radio   Corporation,  Chicago,  HI. 


HAVE  MADE  POSSIBLE  MANY  NEW 
AND  REVOLUTIONARY  DEVELOPMENTS 


PLASKON  offers  a  particularly  desirable  combination  of 
advantages  to  make  your  manufacturing  and  sales  plans 
more  profitable.  Plaskon  Materials  and  Plaskon  engineer- 
ing service  include  a  broad  range  of  features  that  are 
resulting  in  manufacturing  economies,  new  product  ap- 
plications, wider  ranges  of  service,  and  entirely  new  prod- 
uct designs  for  many  different  industries. 

Some  of  the  recent  revolutionary  developments  made 
possible  with  Plaskon  Molding  Compounds,  Plaskon  Resin 
Glues  and  Plaskon  Specialty  Resins  are  illustrated  and 
described  here. 

These  jobs  are  in  commercial  production,  opening  new 
market  and  sales  opportunities  to  industry.  Here  are  the 
Plaskon  Materials  and  their  distinctive  features: 

PLASKON  UREA-FORMALDEHYDE  MOLDING  COMPOUND 

1.  Wide  range  of  lightfast  hues,  from  translucent  natural 
and  pure  white  to  jet  black. 

2.  Smooth  surface,  eye-catching,  warm  to  touch. 

3.  Completely  resistant  to  common  organic  solvents,  im- 
pervious to  oils  and  grease. 

4.  Possesses  high  flexural,  impact  and  tensile  strength. 

5.  Highly  resistant  to  arcing  and  tracking  under  high 
voltages  and  high  frequencies. 

PLASKON  MELAMINE  MOLDING  COMPOUND 

1.  Assures  ample  protection  where  water  or  high  humidity 
prevent  the  use  of  urea  compounds. 

2.  Exceptional  resistance  to  acids  and  alkalies.  Non-porous, 
non-corrodible. 

3.  Under  extreme  conditions  of  heat  and  humidity,  is 
non-tracking,  highly  resistant  to  arcing,  and  has  high 
dielectric  strength. 

PLASKON  RESIN  GLUES 

Hot-  and  cold-setting  resin  glues  to  meet  a  wide  range 
of  requirements  in  the  veneering,  laminating  and  bond- 
ing of  woods.  The  resin  glue  line,  being  infusible  and 
insoluble,  is  permanent  proof  against  extremes  of  temper- 
ature,, gasoline,  oil  and  common  solvents. 

PLASKON  LOW-PRESSURE  LAMINATING  RESINS 

Unlike  conventional  condensation  resins,  these  Plaskon 
Resins  produce  excellent  laminates  with  glass  fibers, 
cellulosic  fabrics  and  paper  for  structural  and  decorative 
purposes.  Rayon,  asbestos,  and  similar  fabrics  can 
also  be  used. 

PLASKON  SPECIALTY  RESINS 

We  can  furnish  gluing,  bonding,  binding,  wet  strength, 
low-pressure  laminating  and  other  types  of  resins  to  meet 
any  specialty  needs. 

PIASKON  DIVISION,  Libbey-Owens-Ford  Glass  Company 

2106  Sylvan  Avenue  •  Toledo  6,  Ohio 

Canadian  Agent:  Canadian  Industries,  Limited  •  Montreal,  Quebec 

PLASKON 


*    MATERIALS    * 


A  n»wly-d»v*loped,  low  pressure  laminating  resin  has  mad*  possible  this  revo- 
lutionary plastic  engineering  material:    a   sandwich   of  parallel  laminates  of 
Plaskon  resin  and  glass  cloth,   separated  by  and  bonded  to  a  featherweight 
"honeycomb"  core  made  of  the  some  resin  reinforced  by  glass  cloth. 


The  patented  cell-type  Reto  Door  made  with  Plaskon  Resin  Olu*  by  th*  Pain* 
Lumber  Company,  Ltd.,  Onhkoth,  Wisconsin. 


The  patents 


"Fib«rglai-Kinton"  laminatei  combine  plastic*  and  fabrics 

staiii-prool  qualities  are  prominently  featured,  when  tin- 
plastics  films  are  applied.  Shower  curtains,  wall  coatings. 
rain  coats,  upholstery  materials,  table  cloths,  etc.  are  a  few 
of  the  consumer  goods  in  which  they  may  l>e  found.  Recent 
developments  in  water  dispersed  resins  have  enabled  coat- 
ing materials  to  be  prepared  which  have  a  much  higher 
solids  content  than  possible  with  solutions  of  the  polymers 
in  organic  solvents. 

Considerable  prominence  has  been  given  to  the  treatment 
of  woods  with  plastics  in  the  form  of  impregnants  or  ad- 
hesives.  The  modern  plywood  industry  depends  upon  the 
laminating  together  of  thin  plies  of  wood  veneer  with 
various  adhesives  under  heat  and  pressure.  The  amount  of 
resin  adhesives  consumed  in  this  application  alone  consti- 
tutes a  major  outlet  for  plastics  materials.  While  much  of 
the  interior  type  plywood  is  bonded  with  glues  of  animal 
or  vegetable  origin,  the  exterior  grades  are  largely  syn- 
thetic resins.  The  latter  type  are  primarily  heat  convertible 
and  have  made  possible  the  more  recent  adaptation  of  fast 
hi  it- pressing  operations  to  the  plywood  industry.  The  role 
of  modern  plastics  as  plywood  adhesives  has  been  the  great- 
est single  impetus  to  the  growth  of  plywood  in  building 
construction,  aircraft  industry  and  naval  construction. 
I  liertiinsetting  adhesives  >urh  as  the  resorcinol  types,  mela- 
iniiies.  and  phenol irs  are  already  prominent  in  this  country, 
while  others  such  as  polyurethanes  have  shown  promise 
•broad, 

The  field  of  plywood  adhesives  in  itself  is  a  tremendous 
Ploitici  and  m«lal  form  a  iliucturally  eHicienl  laminate 


industry.  Take  our  own  West  Coast,  for  example.  There 
are  probably  more  adhesives  used  in  the  plywood  and  lum- 
ber industry  than  compounds  consumed  in  molding  and 
laminating  on  the  West  Coast.  This  difference  will  be  even 
greater  as  overlays  for  plywood  -win  greater  acceptance. 
The  availability  once  again  of  decorative  cloth  prints  and 
paper  prints  will  kindle  renewed  interest  in  the  preparation 
of  "plastics-faced"  plywood.  The  application  of  melamine 
formaldehyde  or  urea  formaldehyde  resins  to  these  porous 
substances  serving  as  facings  not  only  endows  them  with 
the  qualities  of  the  plastics,  but  also  renders  the  plywood 
core  more  stable  by  acting  as  a  moisture  barrier.  The 
beauty  of  the  overlays  lies  not  only  in  the  appearance,  but 
also  in  the  ease  with  which  their  use  may  be  adapted  to 
existing  production  set-ups  for  plywood.  New  developments 
which  will  rapidly  make  costly  equipment  and  manufactur- 
ing procedures  obsolete  are  bound  to  be  resisted  unless  the 
changes  involved  are  revolutionary.  In  this  instance,  no 
changes  in  equipment  are  required. 

The  impregnation  of  wood  veneers  with  synthetic  resins 
and  their  subsequent  bonding  into  a  laminated  structure 
have  excited  the  interest  of  the  plywood  as  well  as  the 
lumber  industry.  Phenolic  resins  have  been  featured  in  such 
treatments,  though  considerable  interest  has  been  shown  in 
dimethylolureas.  Aircraft  propellers  have  been  one  develop- 
ment reaching  a  high  degree  of  commercial  success  with 
( 'omfrcg.  The  presence  of  the  resin  not  only  stabilizes  the 
wood,  but  also  plasticizes  it  sufficiently  during  pressing  to 
permit  the  effective  preparation  of  a  variable  density  struc- 
ture, so  important  to  an  efficient  airplane  propeller.  Other 
developments  in  aircraft  and  naval  fields  have  also  been 
noteworthy,  though  extensive  industrial  utilization  of  resin 
impregnated  woods  still  has  to  be  achieved.  It  is  quite 
probable  that  the  developments  in  resin  impregnated  paper- 
faced  plywood  will  offer  serious  competition,  as  it  too 
offers  much  improved  dimensional  stability. 

Plastics'  plus  inorganics  is  best  exemplified  by  the  addi- 
tions of  furane  resins  to  plaster  of  Paris  forms  (Plasfireg). 
Virtually  a  new  lease  on  industrial  and  decorative  applica- 
tions has  Ixt'ii  given  to  the  plaster  products  through  in- 
fusion with  these  synthetic  resins.  Industrial  tools  and 
patterns  such  as  those  employed  for  stretch  press  dies, 
duplicating  patterns,  dies  for  laminating  purposes,  contour 
gages,  etc.  and  objects  of  arts  such  as  statuaries,  smokers' 
accessories,  advertising  novelties,  etc.  are  now  being  manu- 
factured commercially  by  the  Plaspreg  process,  providing  an 
economical  and  durable  material  of  construction. 

Treatment  of  plaster  products  with  furane  resins  has  been 
described  more  fully  in  an  earlier  issue  of  pl«H««  (October, 
1945).  For  low  cost  and  ease  of  fabrication  and  casting, 
there  are  few  rivals  to  plaster  of  Paris  products.  They  set 
at  room  temperature,  and  the  most  complicated  design  de- 
tails can  be  accomplished  with  a  minimum  of  shrinkage  or 
expansion  (depending  upon  the  grade  of  plaster  product 
employed).  The  permanency  is  greatly  enhanced  through 
impregnation  and  cure  with  the  thermosetting  furane  resins. 
There  are  other  and  lesser  known  contributions  of  plastics 
to  the  field  of  inorganics.  One  striking  example  is  the  em- 
ployment of  a  molded  thermoplastic  with  some  complicated 
machine  detail  such  as  a  thread.  The  ceramic  part  is  termed 
with  the  thermoplastic  as  an  insert,  and  then  as  the  piece 
is  hardened  by  firing  in  an  oven,  the  plastics  decomposes 
under  the  high  temperatures  and  volatilir.es,  still  leaving  the 
details  imprinted  in  the  surface  of  the  ceramic  part. 
Other  examples  may  correctly  include  the  treatment  of  ce- 
ramic bodies  to  increase  their  resistance  to  water  and  water 
vapor.  Silicone  resins  have  made  a  remarkable  contribu- 
tion in  this  direction,  shedding  water  much  like  a  d 
back. 

The  overall  identification  of  rubber  and  plastics  as  mem- 
>CpHti«urd  on  page  80) 


.10 


PLASTICS 


SEPTEMBER  1946 


Figure  it  out... Work  Pays! 


Four    Cars 
"for  the  Prlrv  of  One" 

In  terms  of  automobiles,  see  how  work  pays!  Pro- 
duction 40  years  ago  was  less  than  50,000  cars  an- 
nually. Prices  then  were  more  than  twice  the  cost 
of  cars  after  production  had  climbed  into  millions 
per  year.  Values  today  are  many  times  greater. 
Purchasing  power  of  the  average  wage-earner  has 
more  than  doubled.  Conservatively  stated,  this 
means  that  the  public  gets  the  equivalent  of  about 
four  fine  motor  cars  today  for  less  than  the  relative 
investment  in  one  in  1906! 


Many  other  examples  of  how  work  pays  could  be 
cited.  Only  through  increased  production  .  .  .  not 
slow-downs  or  idleness . . .  can  real  income-increases 
be  attained.  Distortions  of  that  truth  may  persist, 
but  the  fact  remains.  And  the  public  must  be  re- 
minded, repeatedly,  that  only  through  increased 
production  can  the  masses  benefit  by  technological 
advances  of  recent  years  in  industry. 

To  help  manufacturers  improve  their  production 
and  their  products,  MOSI!NEE  paper  technicians 
are  ready  to  work.  Call  us! 


OSINEE 

MOSIHEE  •  WISCONSIN 


PAPER 

MILLS 

COMPANY 


Please  address 

your  letter 

"Attention 

Deft.E" 


SEPTEMBER  1946 


PLASTMCS 


31 


Spilled  ink  holds  no  terror  ior  the  housewife  whose  fur 
niture  is  upholstered  with  "Lumite."  Damp  cloth  and 
a  little  soap  leave  the  fabric  unmarked  and  unstained 


Magnifying  glass  gives  detailed  views  of  some  of  the 
many  weaves  of  "Saran". monofilamenl  fabrics  which 
have  proven  so  popular  for  the  theatre,  transportation, 
home,  restaurant  and  office  upholstery.  Other  appli- 
cations are  as  shoe,  luggage  and  handbag  fabrics 


Developing1 


e,  j.  a 


Development  Manager 
Lumite  Div.,  Chicopee  Mfg.  ~i-p. 

FABRICS  woven  of  plastics  monofilaments  are  facing 
the  hard  row  of  public  acceptance  just  as  any  other  new 
product  does.  But,  in  time,  they  are  certain  to  become 
standard  in  many  applications,  particularly  for  upholstery 
in  practically  all  transportation  vehicles.  Their  many  in- 
herent advantages  practically  guarantee  thi>. 

These  fabrics  are  as  certain  to  win  a  place  for  them-. 
in  upholstery  for  both  indoor  and  outdoor  furniture,  al- 
though the  latter  holds  out  most  promise  at  present. 

Lumite  plastics  fabric  had  its  genesis  in  woven  in-i-ct 
screen,  which  was  developed  well  before  Pearl  Harbor, 
combining  all  the  general  specifications  of  conventional 
iiu-tal  screen  such  as  16  mesh  (16  longitudinal  and  16 
transverse  strands  to  each  square  inch),  a  filament  diameter 
of  15  thousandths  of  an  inch,  and  so  on. 

Compared  with  metal,  it  had  the  additional  characteristics 
of  tremendously  high  impact  strength;  of  never  needing 
painting;  of  ease  of  cleaning;  of  indefinite  resistance  to 
dampness,  salt  air,  and  even  salt  water,  and  to  acids,  grease, 
and  most  solvents.  These  advantages  were  so  numerou-  and 
so  obvious  that  during  the  war  years  the  total  production 
of  Lumite  screen  cloth  was  taken  by  the  armed  forces.  The 
material  won  its  spurs  in  humid  jungles  where  metal  - 
lasted  only  a  few  months. 

At  war's  end  this  insect  screen  required  little  further  de- 
velopmental work  for  conversion  into  a  civilian  product.  A 
thorough  survey  established  the  desirability  of  the  Chicopee 
Green,  which  has  become  standard  for  most  plastics  screen 
cloth.  And  despite  the  dearth  of  insect  screen  cloth  and  the 
insufficient  supplies  of  vinylidene  chloride  (Saran),  it  was 
decided  to  retain  the  15-mil,  16-mesh  construction  in  pref- 
erence to  greater  volumes  of  flimsy  constructions.  This 
put  a  greater  strain  on  available  supplies  of  filament  and 
further  delayed  the  development  of  new  fabrics;  but  a-  in- 
creased supplies  of  vinylidene  chloride  became  available, 
intensive  developmental  work  became  possible. 


la  Fabrics  Market 


Procedure  entails  design   of  fabric,  sample  production,   installation, 
testing  and  observing,  and  design  and  production  of  the  final  product 


The  first  step  in  this  development  program  was  to  de- 
cide the  course  and  method  to  be  followed.  Two  courses 
were  possible  :  ( 1 )  developing  fabrics  along  preconceived 
ideas  and  flooding  every  possible  market  with  sufficient 
quantities  of  fabric  for  all  types  of  experimentation  that 
i  might  present  themselves,  and  (2)  seeking  out  potential 
markets  and  developing  them  carefully,  producing  special 
fabrics  for  each  application  and  cooperating  closely  with 
the  manufacturer-users. 

Both  procedures  had  drawbacks.  The  former  would  be 
expensive  and,  more  serious,  presented  the  danger  of  intro- 
ducing fabrics  into  places  where  they  would  be  found  un- 
suitable. Then  irreclaimable  ground  might  be  lost.  Some 
two  decades  ago,  rayon  was  introduced  in  pretty  much  this 
manner — and  with  pretty  much  this  disastrous  result :  and 
while  numerous  improvements  and  advances  have  been 
made  in  rayon  fibers  since  their  introduction,  the  first  fibers 
did  not  deserve  the  stigma  that  long  clung  to  them  because 
of  their  early  misapplications. 

In  order  that  the  hazards  arising  from  misapplications  of 
the  new  fabrics  might  be  avoided,  the  second  course  was 
chosen.  To  make  haste  slowly  seemed  an  apt  principle. 

Various  Problems  Encountered 

In  the  creation  and  development  of  fabrics,  there  are 
many  problems,  such  as  styling  or  designing,  weaving,  and 
-other  production  processes.  Styling  calls  for  a  knowledge 
of  weaves  and  weave  effects  and  of  colors  and  color  com- 
binations— plus,  of  course,  a  thorough  knowledge  of  the 
fibers  being  used  and  the  fields  of  application  of  the  finished 
fabric.  As  to  the  weaving,  since  insect  screen  and  fabrics 
are  woven  on  conventional  looms  with  only  minor  though 
unique  alterations,  attachments,  and  adjustments  and  since 
the  mill  staff  was  familiar  with  the  characteristics  of  the 
Saran  filament,  producing  a  rather  complete  range  of 
weaves  and  textures  posed  no  great  problem. 


In  the  field  of  color,  however,  this  fortunate  condition  did 
not  prevail.  Available  from  Dow  Chemical  Company 
through  licensed  extruders  were  seventeen  standard  colors, 
all  of  moderate  to  high  value  and  with  very  strong  chroma. 
Eminently  suitable  for  some  purposes,  these  colors  are 
useless  for  others.  Hence,  the  first  work  of  the  stylists  on 
this  development  was  the  creation  of  a  number  of  additional 
colors. 

The  onus  of  developing  the  desired  colors  in  the  Saran 
monofilaments  fell  not  on  Chicopee  but  upon  the  extruder 
and  the  manufacturer,  National  Plastic  Products  Co.  and 
Dow  Chemical  Company.  The  creation  of  such  color 
matches,  in  light-fast  and  non-crocking  form,  is  apparently 
not  easy ;  but,  although  time  was  consumed  in  the  proc- 
ess, colors  were  made  available  in  forty  odd  standard 
shades,  selected  in  every  case  to  provide  the  greatest  pro- 
duction flexibility  and  to  meet  the  requirements  of  95%  of 
all  the  requests  made  for  specific  shades. 

Where  time  is  not  important,  practically  any  other  specif- 
ic shade  of  color  in  the  basic  filaments  is  possible.  Usually, 
creation  of  such  a  new  color  takes  several  weeks. 

Although  knowledge  and  experience  gained  in  the  past 
year  has  resulted  in  a  modest  but  growing  line  of  "standard" 
fabrics.  Chicopee's  Lumite  Division  continues  to  regard 
itself  not  as  a  marketer,  but  rather  as  a  developer  of  woven 
plastics  fabrics.  Consequently,  all  current  production  of 
fabrics  is  going  directly  to  manufacturers  who  utilize  them 
in  their  own  products.  In  addition,  practically  all  of  the 
development  work,  of  which  much  is  still  being  done,  is 
carried  on  in  connection  with  manufacturers. 

This  development  work  still  follows  the  basic  pattern 
originally  established.  It  is  to  create  a  special  fabric,  styled 
and  designed  in  accordance  with  the  ideas  of  our  staff  and 
that  of  the  user,  for  the  specific  application;  to  produce  it  in 
sample  quantities ;  to  install  the  fabric ;  to  test  and  observe 
the  installation ;  and.  finally,  to  design  and  produce  the  final 


i« 


fabric,  based  upon  the  result*  previously  obtained.  Perhaps 
a  few  specific  examples  will  be  of  interest. 

At  present,  much  of  the  l.umite  fabric  being  produced  is 
used  for  automobile  seat  covers  in  a  variety  of  designs.  Here 
the  advantages  include  easy  cleaning,  resistance  to  stains, 
long  wearing  abilities,  seating  comfort  induced  by  the 
ability  of  the  fabric  to  breathe,  and  so  on.  Automobile  seat 
cover  fabric  presented  no  development  difficulties  of  special 
importance,  aside  from  colors,  designs  and  weave  textures ; 
but  the  same  basic  development  pattern  was  followed. 

In  furniture,  it's  a  different  story.  Lumite's  first  major 
assignment  in  this  field  was  a  fabric  for  the  upholstery  of 
350  audience  seats  in  the  studios  of  WABD,  television  sta- 
tion in  Wanamaker's  Department  Store  in  New  York. 
While  these  studios  were  still  in  the  drawing-board  stage, 
the  designers  wanted  a  seat  cover  fabric  that  incorporated 
every  advantage  in  comfort,  appearance,  ease  of  cleaning, 
long  wear,  attractiveness  and  general  suitability.  It  was  at 
that  point  that  the  actual  work  started. 

Our  first  contact  was  with  F.  J.  Krick,  assigned  to  dec- 
oration of  the  studios.  Several  sessions  devoted  to  colors 
and  weaves  followed,  before  a  final  decision  was  made  on  an 
antique  green  shade.  To  accomplish  this,  it  was  necessary  to 
combine  the  then  available  standard  strong-chroma  colors  in 
such  a  manner  and  in  such  a  weave  as  to  give  the  general 
overall  color  effect  desired.  At  the  same  time,  an  attractive 
weave  had  to  be  retained. 

Krick  first  had  made  clear  the  exact  color  and  shade  that 
he  desired,  submitting  an  actual  chip  of  the  specific  color. 
With  this  knowledge,  it  was  possible  to  submit  35  samples 
from  which  to  make  a  selection.  Then  followed  the  selec- 
tion of  a  weave  which  had  to  be  modified  slightly  from 
Krick's  final  choice  in  order  to  improve  the  fabric's  wearing 

Panoramic  display  of  various  easy  to-clean,  wear-resist 
ant    "Lumite"    fabrics,   made   of    "Saran"   monofilaments 


Long-wearing  abilities  and  seating  comfort  of  this  versa- 
tile   material    make    it    desirable    for    aircraft    upholstery 

qualities  Altogether,  only  12  days  were  consumed  in  sub- 
mitting the  35  samples  after  the  first  s»->sjon  on  color  and 
weave. 

There  have  been  additional  developments  in  furniture 
and  in  seating  applications  since  this  original  one:  Inn  the 
method  and  sequence  have  been  much  the  same.  It  is  an- 
ticipated that  future  developments  will  again  pretty  much 
follow  this  same  pattern. 

Another  interesting  development  was  that  of  l.iiinil,-  radio 
grille  fabrics.     This  possibility  was  first  brought  to  <  In- 
copee's  attention  by  Alexander  II.  (iirard,  architect  and  de- 
signer.     Working    from    his    ideas    and    suggestions, 
copee's  first  job,  then,  was  to  create  a  radio-grille 
with,   first,   attractiveness,   which    was   not   too   difficult    in 
view  of  the  wide  range  of  colors  and  designs  |>osSJblt 
ond.   adequate   sound   transmission;   and.   third,   ability   tn 
mask  the  speaker  cone  or  such  other  of  the  radio  mechan-j 
isms  as  was  covered  by  the  fabric.     In  addition,  the  fabric 
had  to  add  something  to  the  general  over-all  design  of  the| 
radio  set;  it  had  to  justify  its  higher  cost  on  other  ^roun<l>. 
than  simply  an  ability  to  transmit  sounds  and  to  close  up 
the  speaker  hole. 

("hicopee's  stylists  attacked  this  problem  of  designing 
suitable  fabrics  with  proper  weave  characteristics  and  color 
combinations  and  came  up  with  two  designs — one  to  blend 
with  blond  wood  and  to  contrast  with  dark  wood,  and  the 
other  with  these  characteristics  in  reverse. 

These  fabrics  were  then  produced  and  submitted  for  the 
required  experimental  tests  and  mock-ups  by  lx>th  the  de- 
signing staff  and  the  engineering  staff  of  several  radio  man- 
ufacturers, by  whom  they  were  found  satisfactory. 
then,  many  additional  color  combinations  and  weaves  have 
lieen  worked  out  for  radio  designs.    In  virtually  every  case, 
each   new  fabric  has  lK-en   the   result   of  co-operation  and 
collaboration  between  the  staff  of  the  end  user  and  tli 
of  the  l.mnite  division. 

It  might  be  well  to  interject  here  mention  of  the  absolute 
necessity  of  a  thorough  understanding  of  each  staff's  re- 
quirements and  sjx-cifications  by  the  other.  KrequentN 
complete  disclosures  regarding  possible  applications  and  re- 
quirements cannot  !«•  made,  but  a  thorough  understanding 
of  the  exact  terms  of  such  specifications  as  are  stipulated  it 
•  •ss.-iiiial.  An  instance  in  the  development  of  radio  grille 
fabrics  is  an  excellent  example. 

\.v.nilinij  to  a  number  of  radio  manufacturers,  the  grille 
(Continued  on  pagt  79) 

.11  SKITKMBKR  1946 


He  runs  his  road 


with 
GEON-insulated  wire 





"Rainbow  Cable" 
control  wire  developed 
and  manufactured  by  Pbalo 
Plastics  Corp.,  Worcester,  Mass. 


GEON's  advantages  make  it  ideal  insulating 

material  for  instrument,  home,  industrial 

and  utilities  wiring 

THE  things  that  Bill  used  to  do  with  his  hands  to 
keep  his  railroad  running— coupling  and  uncoup- 
ling cars,  loading  and  unloading,  turning  switches- 
are  all  done  by  electricity  on  the  modern  American 
Flyer  that  huffs  and  puffs  and  belches  smoke  just  like 
its  full-sized  counterpart. 

That  calls  for  connecting  wires  that  are  easy  to  iden- 
tify, that  stand  rough  usage,  that  won't  crack,  get  gum- 
my or  peel,  that  will  keep  fire  hazards  to 
a  minimum.  That's  why  the  A.  C.  Gilbert 
Company  selected  wire  with  insulation 
made  from  GEON.  It  can  be  brilliantly 
colored  in  a  wide  range,  it  wears  indef- 


Geon 


initely,  resists  aging  and  ozone,  and  is  self-extinguish- 
ing—won't support  combustion. 

These  and  other  properties  of  insulation  made  from 
GEON  have  earned  it  an  important  place  in  every  part 
of  the  electrical  industry.  The  thinner  coating  of  insu- 
lation made  possible  by  GEON's  electrical  properties 
permit  more  conductors  per  conduit.  Resistance  to  oil 
and  grease,  acids,  alkalis,  moisture,  heat,  cold,  and 
most  other  normally  destructive  factors  mean  that  in- 
sulation made  from  GEON  can  be  used  everywhere. 

The  next  time  you  order  •wire — for  manufacturing, 
home,  or  industrial  wiring— be  sure  to  specify  wire  insu- 
lated with  GEON,  now  being  made  by  leading  wire  and 
cable  manufacturers.  Or  for  information 
about  special  applications  please  write 
Department  U9,B.F. Goodrich  Chemical 
Co.,  Rose  Building,  Cleveland  15,  Ohio. 
In  Canada:  Kitchener,  Ontario. 


B.  F.  Goodrich  Chemical  Company 


A  DIVISION  OF 
TMES.f  GOODRICH  COMPANY 


V. 


STOKES  MOLDING  IS 


v.m 


attention. 


because 


Piece 


the  P  ess 


ing  ^  SS  Stokes  Automatic 
means  that  B  com. 

Molding  Machin"  s 

pjetely  «f-^*;   sensitive 

must    pass    »          £         >  to  eject 
trap.  Should  a  pcet^ 

lor  any  reasonu 


ATHER  FEATURES  that  mean 

chme—  ie         3-  ejection. 

ing.  curing.  0Penel"gwder  meas- 


. 

ical    and   compre 
the  mold. 


Stokes  Model  23S  50-Ton  Automatic 
Molding  Press.  Covered  by  U.  S. 
and  foreign  patents. 


AUTOMATIC  MOLDING   is  foolproof,  flexible,  economical 


The  above  and  other  Stokes  developments  provide 
molding  presses  that  are  reliable,  foolproof,  eco- 
nomical. An  unskilled  man  can  run  a  battery  of 
them.  These  machines  are  producing  a  wide  va- 
riety of  parts,  in  hundreds  of  shapes  and  sizes,  for 
such  diverse  products  as  electrical,  home  and  office 
appliances,  radio  and  electrical  equipment,  auto- 


motive accessories,  toys,  novelties,  many  others. 

Parts  produced  automatically  are  identical,  low 
in  flash  loss,  accurate  in  dimensions,  of  highest 
quality.  Investigate  Automatic  Molding. 

F.  J.  STOKES  MACHINE  COMPANY 

6O40  Tabor   Rood,   Philadelphia   20,   Penna. 


MOLDING  EQUIPMENT 


Forming 

Silk-Screened  Acrylics 


Beauty  and  symmetry  of  design  silk-screened  on  methyl  methacrylate  sheet  are  unaffected  by  forming  operations 


Special  paint  permits  the  forming 
of  acrylics  after  silk-screening 


Square-topped  and  other  complex  shapes  present  no  problem 


THE  process  of  silk-screen  printing  on  contoured  plas- 
tics surfaces  has  heretofore  been  attended  by  so  many 
difficulties  as  to  make  it  virtually  unfeasible.  In  fact,  ex- 
cept for  printing  on  simple  cylindrically  curved  surfaces,  for 
which  a  special  machine  is  used  to  make  the  curved  piece 
ride  along  the  screen,  silk-screen  work  on  any  but  a  flat 
plane  surface  has  been  neither  mechanically  nor  economi- 
cally practicable. 

The  solution  to  the  problem  has,  logically,  been  sought  in 
a  process  that  would  permit  forming  of  the  plastics  piece 
after  silk-screen  application,  and  there  have  recently  been  a 
number  of  developments  along  this  line.  Notable  among 
these  has  been  a  method  developed  by  the  Schulsinger  Com- 
pany, New  York.  The  two  most  outstanding  claims  made 
for  it  are  high  adhesion  of  design  to  plastics,  and  pliability 
of  the  design  when  the  material  is  formed. 

The  key  to  the  process  is  in  a  paint  designed  specifically 
for  silk-screen  printing  on  methyl  methacrylate,  and  is  an 
outgrowth  of  the  cooperation  of  the  Schulsinger  firm  and 
the  Keystone  Refining  Co.,  Philadelphia.  The  paint,  a  free- 
flowing  compound  of  heavy-syrup  consistency,  is  "short," 
so  that  it  can  be  used  to  carry  out  fine  screen  detail  without, 
"flow-out"  and  yet  retain  adhesion.  Adhesion  is  specific, 
and  the  adhesion  characteristic  is  high.  It  is  claimed  that 
age  toughens  the  paint  and  improves  the  bond  with  gradual 
escape  of  the  solvents.  Drying  time  is  brief — about  15  min. 

Aside  from  its  adhesive  strength,  the  most  important  char- 
acteristic of  the  paint  is  its  resistance  to  heat,  since,  when 
(Continued  on  page  68) 


SEPTEMBER  1946 


PLASTICS 


37 


A'ryci  Fitrrt  photi 


Pulp  resins  can  be  easily  molded  into 

large,  strong  articles — even  those 

with  thin  sections  and  undercuts 


JMton  J4. 


an 


S. 


ncS 


ONE  of  the  important  types  of  plastics  materials  re- 
sults from  a  combination  of  the  techniques  of  pulp 
molding  and  resin  impregnation.  Although  each  technique 
in  itself  is  not  new,  the  combination  yields  a  material,  vari- 
ou-.lv  called  resin  fibers,  pulp-resin  preforms,  or  simply 
pulp  resins,  which  can  Ixr  used  for  the  production  of  large, 
high-strength  articles  containing  thin  sections  and  under- 
cut-. 

Resin  fiber  articles  are  resistant  to  wear,  mild  acids,  and 
alkalies,  and  have  the  durability,  smoothness,  and  finish  of 
molded  plastics.  The  general  physical  and  chemical  proper- 
ties of  the  commercially  available  grades  of  resin-fiber 
compositions  are  listed  in  an  accompanying  table. 

Ordinary  thermosetting  molding  composition-,  have  cer- 
tain inherent  limitations  for  such  applications.  When  stand- 
ard wood  flour  or  cotton  flock  molding  powders  are  n-ed 
in  large  cabinet  dies  containing  a  deep  draw  and  sharp 
corners,  the  molding  needs  are  such  that  excellent  flow  of 
the  powders  or  higher  pressures  are  required.  The  re-nlt- 
ing  article  has  an  excellent  finish  but  only  fair  physical 
properties.  If  rag  or  cord-filled  molding  roni|M>umN  are 


used,  the  desired  strength  properties  could  be  obtained  only 
at  higher  molding  pressures,  with  a  resulting  poor  surface. 

Pulp-resin  preforms  made  to  conform  very  closely  to  the 
desired  dimensions  of  the  finished  article  eliminate 
inherent  deficiencies.     The  press  is  fed  with  a  pulp-resin 
mixture  that   is  uniformly  distributed  throughout  the  dieJ 
The  resulting  flow  that  takes  place  during  the  actual  mold- 
ing operation  is  confined  to  the  resin  only,  and  tin 
molded  product  is  therefore  composed  of  a  uniform  material 
of  continuous   felted   and    interlocked    fibrous   reinforcing 
structure  bound  together  by  a  synthetic  resin.    The 
ing  is  dense  and  hard  with  a  smooth  surface  and  po~ 
superior   strength   properties.     The   pulp-resin   industry   is 
based  on  the  familiar  molded  pulp  process  which  produce! 
plates,    dishes,    and    packing    sheets.      I  >ies    covered    with 
screening  similar  to  the  fourdrinier  wire  used  on  pap 
machines  are  employed.     After  the  preparation  of  pulp 
the  heaters,  the  dies  of  desired  sha|>es  ;,,c  immersed  in 
|iulp  Mis|u-iisinii,  and  mats  are  formed  on  them  by  the  ;i|: 
cation    of    vacuum.      The   dies    with    their    mats   are 
brought    into  contact   with   a    female   die.   and    pressure 


Comparison  of  Properties  of  Molded  Pulp-Resin  Preforms  and  High 
Impact  Molding  Compounds 


Material 

Molding 

Reiin 

Temile  Strength 

Flexural 

Impact  Strength 

Water 

Prettwre 

Content 

(pii) 

Strength 

ill  Ib   In 

Absorp- 

<P»0 

(<jg) 

(p«l) 

af  natch  liad) 

tion. 

74  hr 

(56M 

Kraft  pulp  -r  «tm  preform  

...     880. 

53  

..13,400*1,130. 

18,200-1,050... 

...1.09*0.00  

.  ..0.42 

60'  ',  pulp,  40'  ,  macerated  fabric-win  pre- 

form   

...     880. 

55  

..13.500-      689. 

16,100*1,300... 

...2.34*0.03  

.  .  .  0.60 

Macerated  fabrlc-retin  preform  

...     880. 

55  

..    9,500*     705. 

....12,200*     490... 

...3.00*0.08  

.  ..0.31 

Macerated  fobot  filled  molding  compound.  .  . 

...3,000. 

50  

..    5,500*     855. 

10,200*     550... 

...3.50*0.13  

...  1  .67 

Cotton  cord  filled  molding  compound  

...3,000. 

50  

.  .    4,800*     625. 

12,400*  1,050  

..8.00*0.18  

.  .  .  1.91 

38 

F  i    \ 

*TI  CS 

SKITEMBER 

1'Mfi 

tjei-e'sliow 

*       till?.'  ofm* 


A  fresh  architectural  departure,  this  clean  cut,  modern 
store  was  designed  by  Raymond  Loewy  Associates.  At 
Piser,  Display  Director  for  John  Ward  Shoe  Stores,  wanted 
shoe  and  hosiery  stands  to  match  its  mood.  So  he  ... 


PLEXIGLIS 


PLEXIGLAS  is  a  trade-mark,  Xtg.  "U.S.  Pat.  Of. 


Ingeniously  adopting  standard  engineering  drawings,  Mr. 
Piser  and  staff  originated  "Cycloramic  Design"—  beautifully 
cut  and  polished  PLEXIGLAS  parts  that  can  be  arranged  in 
many  different  ways  to  provide  unusual  displays.  They  were 
cut  from  PLEXIGLAS  blocks  two  and  one-half  inches  thick  and 
fabricated  by  M.  Goldsmith  Co.,  Inc.,  New  York  City. 


"•to  make  exciting 

DISPLAY  FUTURES' 

ff   Your  own  store  counters  and  windows  can  be  brightened 
by  the  use  of  sparkling,  crystal-clear  PLEXIGLAS  display  fixtures. 

H    PLEXIGLAS  provides  a  glittering  background  for 

merchandise  .  .  .  makes  the  goods  attractively  prominent 

wherever  they  are  shown.  And  this  light  weight  plastic 

is  exceptionally  strong  and  tough  .  .  . 

'     We'll  be  glad  to  suggest  a  reliable  fabricator  for  your  own 

designs.  Or  ask  your  supplier  to  show  you  the 

many  interesting  and  unusual  PLEXIGLAS  fixtures  that 

will  highlight  your  displays. 


Only  Kobm  &  Tiaas  makes 

PLEXIGLAS 
^crylicSbects  and  'Molding  Potvders 


RO 


COMPAN 


W,I.S///W;TOY  SQL  ARE,   PHILADELPHIA   s.   PA. 

.Manufacturers  of  Chemicals  including  Plastics . . .  Synthetic  Insecticides . . .  Funjicides . . .  Ewymes . . .  Chemicals  lor  the  Leather,  Teitile.  Enamelware,  Snober  and  other  Industries 


Effect  of  Resin  Content  on  Properties  of  Kraft  Pulp-Phenolic 
Preforms  Molded  at  800  Psi  and  320  F 


•Mi 

Content 
(%} 

Fltxural 
Strength 
(p«i) 

Tenlil* 
Strength 
(p»i) 

Impact  Strength 
(ft-lb   in  of  notch 
Izod) 

Water  Absorp- 
tion, 24hr 
(%) 

13  400  •  1  130 

)  8,200  *  1  ,050  

I  09*0  18  

<X42l 

45  
35  
25  
1  j                          

...13,500*1.170  
12,600*1,140  
12,600*     330  
12,200*1.030  

16,400*     710  
18,600*1,365  
1  5,200  *     575  
14,000*     740  

2.72*0.16  
4.80*0.57  
6.64*0.78  
6.96*0.64  

0.64 
,  0.82 
24.3 
,  70.6 

Data  by  MomoiKo  Oi«nkal  Company 


applied  to  compress  the  preform  to  a  desired  thiekne-s.  By 
the  simultaneous  application  of  air  pres-ure  to  the  male  die 
and  vacuum  to  the  female  portion,  the  preform  i>  trans- 
ferred  to  the  female  die.  It  is  then  dropped  on  to  a  con- 
\cyor  belt,  where  it  is  subsequently  dried. 
The  resin  may  be  dispersed  throughout  the  pulp  in  the 


M     H  :•::.       '     ' 


Ground  phenolic  resin  i*  added  to  laboratory  size  pulp 
beater  in  making  rerin  fibers.  Below,  wet  preform,  made 
over  a  vacuum  screen,  it  being  removed  (rom  a  pulp  vat 


I 


beater  or  stock  tank,  and  the  mixture  sent  through  a  pre- 
forming unit  \\lu-re  the  resin  and  pulp  are  leltetl  out 
together.  The  pulp  may  be  preformed  and  then  resin  im- 
pregnated. These  steps  are  illustrated  in  the  accompanying 
flow  sheet.  The  effect  of  the  type  of  resin  used  w  ill  l>e 
discussed  later. 

Several  techniques  may  be  used  for  the  product  ion  of 
the  finished  articles.  The  preforms  may  be  molded  in  con- 
veiitional  metal  dies  if  the  design  permits.  However,  in 
some  cases  it  is  necessary  and  advantageous  to  use  an  ex- 
panding rubber  bag  mold.  This  is  an  extremely  effective 
method  insofar  as  axial  pressure  is  exerted  equally  and 
simultaneously  on  all  parts  of  the  preform.  However, 
the  use  of  the  bag  technique  produces  a  molding,  one  side 
of  which  has  a  rough  surface.  In  certain  applications  this 
is  not  desirable,  but  it  is  of  no  consequence  in  articles  -urh 
as  radio  cabinets  or  business  machine  housings.  In  addi- 
tion, the  size  of  the  molded  piece  is  not  limited  by  available 
press  capacity.  This  makes  possible  the  economical  mold- 
ings of  large  sections  and  eliminates  the  prohibitive  ex-J 
pense  of  large  presses. 

One  of  the  outstanding  applications  of  fibrous  pi 
compositions  has  been  in  the  production  of  serving  tra\ 
which  are  being  used  extensively  by  the  armed  force - 
pitals,  restaurants,  hotels  and  similar  institutions.      These 
trays  have  an   impact  strength  of  4  to  5  times  that  of  | 
ordinary  thermosetting  molding  compounds.     They  will  not 
buckle,  crack,  or  bend  out  of  shape  when  overloaded.    I  hey  | 
are  durable  and   will   not   shatter   or   chip   with   ordinary 
handling.     Their  smooth  mirror-like  finish   is  not  merely 
a  surface  effect  but  is  an  integral  part  of  the  composition. 
In  addition,  the  trays  may  be  sterilized  with  boiling  water  I 
and  antiseptic  solutions  and  are  impervious  to  the  effects  of 
alcohol,  greases,  and  ordinary  acids  and  alkalies.    The  o  <n\- 
bination  of  all  these  properties  in  one  material  readily  ex- 
plains the  wide  acceptance  of  the  tray. 

The  material  also  has  been  incorporated  into  a  new  type) 
of  baby  high-chair  because  of  its  resistance  to  splintering 
and  denting,  its  lightness  (for  easy  handling),  its  clean-1 
ability,  and  imperviousness  to  food  and  mild  acid  stain-. 

The  versatility  of  pulp-resin  moldings  is  shown  by  their 
usr  in  adding  machine  housings.  This  unit  is  required  to 
be  a  large  hollow  form,  having  dimensional  stability,  -u- 
perior  strength,  and  good  dielectric  properties.  The  hous- 
ing must  be  able  to  take  engraving  and  have  a  |>ermaiicnt 
attractive  finish.  In  addition,  it  must  not  become  brittle 
or  crack  at  low  temperatures  and  must  resist  the  effect-  »f 
constant  jarring.  Besides  meeting  these  requirements,  the 
preforms  also  make  use  of  processing  methods  which  allow 
for  rapid  and  cheap  production.  The  single  molding  open! 
tion  eliminates  the  machining  necessary  in  finishing  metal 
i-a-tings.  The  need  for  interior  insulation  is  eliminated 
IH  cause  the  molded  pulp-resin  coin|M>und  is  non-rcvc: 
ing. 

Molded  pnlp-resin  pnxlucts  played  an  important  role  m 
the  war  effort.  One  of  their  most  successful  war-time  apl 
plications  was  a  valve  handwhrel.  (  ritic.il  metal  -In triage* 
made  it  extremely  n. ve-.uy  to  find  a  suitable  replacement 


10 


SKPTKMBER  1916 


Properties  of  Molded  Pulp-Resin  Compounds 


Property 


Value 


Specific  gravity 1 .39 — 1 .45 

Specific  volume  (cu  in  'Ib) 19.1 — 19.9 

Tensile  strength  (psi) 4,500 — 9,000 

Izod  impact  strength  (ft-lb  'in  of  notch) 

Flatwise 1.76—4.4 

Edgewise 0.87 — 1 .63 

Flexural  strength  (psi) 

Flatwise 1  2,000—1  8,000 

Edgewise 1 1,300—1  8,600 

Compressive  strength  (psi) 

Flatwise 22,800—35,200 

Edgewise 1  5,800—2 1 ,500 

Endwise 1  9,000—24,800 

Colors Medium  to  dark  shades 

Clarity Opaque 

Machinability Good 

Odor None 

Taste None 

Effect  of: 

Age None 

Prolonged  exposure  to  sunlight Surface  discoloration 

Metal  inserts Inert 

Boiling  in  water  24  hr None 

Boiling  in  mild  soap  solution  24  hr None 

Distortion  after  boiling  in  water  24  hr None 

Water  absorption  (%  on  48-hr  immersion) 0.22 — 2.39 

Effect  of: 

Oil  and  gasoline None 

Weak  acids None  to  slight 

Strong  acids,  oxidizing Decomposes 

Strong  acids,  reducing  and  organic None  to  slight 

Weak  alkalies Slight 

Strong  alkalies Decomposes 

Ethyl  alcohol None 

Ethyl  ether None 

Acetone None 

Xylol None 

Carbon  tetrachloride None 

Pyridine None 


for  the  aluminum  wheels  that  were  being  used.  After  many 
types  of  materials  were  tried  and  found  unsuited  for  the 
requirements  in  question,  a  molded  pulp-resin  handvvheel 
was  used  that  passed  all  tests  and  specifications.  In  addi- 
tion to  performing  as  successfully  as  their  metal  prede- 
cessors, they  offer  several  advantages.  They  meet  the 
strength  requirements  by  their  ability  to  withstand  extreme 
torques.  The  incorporation  of  metal  hubs  will  not  set  up 
any  weakening  stresses  or  strains,  and  the  bond  between 
the  plastics  and  metal  is  permanent,  with  the  hub  immov- 
able. The  light  weight  pulp-resin  wheels  eliminate,  in 
some  installations,  the  necessity  for  the  support  of  heavier 
wheels,  thereby  providing  more  accessibility  and  the  easier 
alignment  of  working  parts. 

The  dielectric  properties  of  molded  pulp-resin  handvvheels 
are  a  decided  advantage  where  they  are  to  be  used  in  close 
proximity  to  electrical  installations,  such  as  panel  control 
boards.  When  used  on  steam  pipes  or  ovens,  the  non- 
conductivity  properties  allow  for  operating  with  bare  hands 
without  fear  of  burns.  On  outside  cold  weather  installa- 
tions or  refrigeration  systems  bare  hands  will  not  freeze 
to  the  plastics  as  they  will  to  metal.  Important  in  safety 
considerations  is  the  fact  that  the  molded  handwheels  may 
be  produced  in  colors  which  can  be  used  for  quick  and 
positive  identification  of  different  piping  systems.  Addi- 
tional safety  precautions  may  be  insured  by  molding  direc- 
tions, arrows,  and  other  information  into  the  wheel.  The 
combination  of  advantages  gives  promise  of  increased  future 
uses,  particularly  multiple  piping  installations. 

The  use  of  pulp-resin  preforms  for  small  moldings  is  not 
too  promising.  With  an  increase  in  the  size  of  the  molded 
piece,  the  choice  of  a  pulp-resin  becomes  far  more  attractive, 
and  several  of  these  applications  are  at  present  being  ex- 
ploited. Typical  examples  of  this  cla"ss  are  plates  and 
serving  trays,  alarm  clock  cases,  equipment  bases,  telephone 


Disassembled  molds  (below)  are  used  in  the  final  molding 
operation  on  a  pulp  preformed  sample.  Above,  operator 
positions  molds  in  the  press  for  experimental  molding  run 


stands,  and  business  machine  housings.  The  important 
factor  to  consider  in  applications  of  this  type  is  that  the 
cost  requirements  will  govern  the  choice  of  materials  and 
that  there  is  strong  competition  with  regular  thermosetting 
molding  compounds. 

The  largest  field  of  use  of  pulp-resin  moldings  will  be 
in  the  production  of  large  moldings  where  superior  physical 
strength  properties  are  required  and  a  good  appearance  is 
a  desideratum.  These  applications  include  table  and  desk 
tops,  refrigerator  doors,  automotive  and  decorative  panels, 
radio  cabinets,  furniture,  and  many  other  potential  uses  in 
a  virtually  unexplored  field.  The  ability  of  the  pulp-resin 
moldings  to  lend  themselves  to  reasonably  complex  designs 
in  large  pieces  gives  them  a  considerable  advantage  over 
the  competitive  laminated  materials. 

Reference  was  made  before  to  the  fact  that  various  types 
of  resin  may  be  used  in  the  pulp  preforms.  The  type  ac- 
tually used  will  depend  on  the  particular  process  of  incor- 
poration. In  general,  there  are  two  main  types.  The 
(Continued  on  page  61) 


SEPTEMBER  1946 


PLASTICS 


41 


Group  of  injection  molded  parti,  including  radio  grilles,  used  in  1946  Ford.  Mercury,  and  Lincoln  can.  and  Ford  truck* 

In-Plant  Molding 
Expedites  Auto  Parts 

Ford  Motor  Company  maintains  a  large,  specialized  molding  plant 
for  compression  and  injection  molding  of  its  automotive  parts 


Ck 


FOLLOWERS  of  the  design  and  construction  of  auto- 
motive equipment  are  well  aware  that  the  Ford  Motor 
Company  is  a  great  believer  in  plastics  and  among  the 
largest  users»of  plastics  products,  besides  having  pioneered 
in  certain  types  and  applications.  It  is  not  so  widely  known. 
however,  that  the  Ford  molding  plant  ranks  among  the 
largest  in  use,  has  a  wide  variety  of  equipment,  practices 
all  types  of  molding  and  turns  out  a  large  assortment  of 
molded  products  in  great  volume  and  at  a  rapid  rate.  . 

Within  about  a  decade,  the  Ford  plastics  molding  equip- 
ment has  been  completely  replaced  and  the  number  of  presses 
has  been  increased.  The  earlier  installation  of  steam  heated 
presses  operated  from  a  central  hydraulic  installation  no 
longer  exists.  All  molding  equipment  is  comparatively  new, 
and  much  of  it  is  of  the  very  latest  type. 

There  arc,  in  all,  for  injection  molding,  eleven  Lester- 
I 'lux-nix,  nine  Reed- Prentice  and  one  H.P.M.  machines  and, 
for  compression  molding,  some  forty  press,-,  of  Lake  Erie. 
French  Oil  Mill  Machinery,  Watson-Stillman  anil  Stokes 
types.  Most  of  the  compression  presses,  excepting  the 

Stokes  presses,  are  of  300-ton  capacity. 

Early  in  the  recent  war,  the  Ford  plant  for  making  soya 
molding  resins  was  dismantled  to  make  way  for  building 
war  products  and  has  not  been  reinstalled.  Aside  from  rul>- 
ber,  which  will  not  be  dealt  with  here,  the  chief  plastics  now 
used  are  the  phcnolics,  furfural  resins  and  melamine  resins 
for  compression  or  transfer  molding  and  the  aceto-butyrate, 
vinyl  and  acrylic  resins  for  injection  molding. 

i  "'impression  and  transfer  molding  (including  the  new 
transfer  ty|x-  which  is  also  railed  plunger  molding!  are 
used  chiefly  for  ignition  components,  including  those  for 


passenger  cars,  trucks  and  tractors.     Most  of  the  injection  j 
moldings  are  in  aceto-butyrate  and  are  chiefly  for  knobs, 
handles,  radio  grilles  and  other  parts  that  perform  both 
decorative  and  utility  functions.     The  vinyl  resin  is  used] 
for  making  flexible  sleeves  to  cover  ignition  cables  where 
they  leave  distributors,  and  replaces  rubber  parts  that  were 
subject  to  deterioration. 

There  is  not,  in  the  Ford  setup,  much  that  is  unusual  in 
injection  molding  practice  except  that  careful  controls  help 
to  insure  rapid  and  dependable  molding.  The  latter  is  aided 
and  rejects  are  minimized  by  treating  all  aceto-hutyrate 
granules  to  insure  low  moisture  content  before  delivery  to 
machines.  This  is  done  by  feeding  the  material  onto  a  U-lt 
which  carries  it  through  an  oven  under  infra-red  lamps  in 
2  to  10  min.,  during  which  the  temperature  is  raised  to  isn ' 
I*"  to  lower  moisture  content.  At  the  end  of  the  belt,  the 
granular  material  is  placed  in  closed  containers  in  which 
it  is  sent  to  machines  and  kept  covered  until  fed  into  mold- 
ing press  hoppers. 

\  somewhat  unusual  feature  is  the  molding  of  the  vinyl 
sleeves.  This  is  done  in  four-cavity  molds  each  having  four 
arbors  supported  by  rods  that  fit  holes  in  the  die  anil  are 
pushed  forward  as  the  die  opens  to  move  the  arbors  out  at 
the  rear  mold  Mock  cavities  with  the  sleeves  molded,  one 
around  each  arbor.  To  remove  the  sleeves,  an  air 
directed  against  each  arbor  just  above  the  sleeve.  This  jet 
•is  the  sleeves  and  blows  them  off  the  arbors.  Hie 
sleeves  are  caught  by  the  press  operator  and  are  laid  in  a 
tote  box. 

Vinyl  plastics  used  for  this  operation  is  heated  in  the 
machine  to  430°  F  and  the  machine  runs  through  its  ,  \r|e 


I'l.ASTU  S 


SKITKMKKR  1946 


There's  no  "coin-flipping"  substitute 

A    ji 

for  experience  in  plastics, 
regarding . . . 


MACK  MOLDING  COMPANY 

130    MAIN    STREET,    WAYNE,    NEW   JERSEY 

,IES     OFFICES:       NEW      YORK,      CHICAGO,     DETROIT,      INDIANAPOLIS,      BOSTON 

SEPTEMBER  1946  PLASTICS 


Hood  latch  pull  handle*  are  injection  molded  in   16-cavity 
mold,  and  theii  cooling  is  hastened  by  submersion  in  water 


A  jet  ot  compressed  ail  is  used  to  eject  the  flexible  vinyl 
ignition-wire  sleeves  from  the  arbors  around  which  they  are 
molded.  When  mold  is  closed,  each  arbor  is  centered  in  the 
corresponding  mold  cavity.  Below,  butyrale  granules  pass  on 
conveyor  under  Infra-red  lamps  which  lower  moisture  content 


in  45  -ec.     Some  two-cavity  a>  well  as  four-cavity 
are  also  used  for  producing  the  same  parts.     Timing   on 
these  and  other  injection  molding  jobs  is  automatic,  each 
cycle  starting  with  pressing  of  a  push  button  or  closing  of 
a  gate  that  is  slid  along  one  side  of  the  die. 

With  automatic  timing,  the  operator  is  more  or  less  free 
to  perform  other  operations  while  the  die  remains  , 
and  is  tilled  by  advance  of  the  injection  plunger.    With 
moldings,  the  operator  has  time  to  cut  them  from  tin 
with  a  knife  and  place  them  in  tote  boxes,  throwing   the 
sprue,  runners  and  any  imperfect  moldings  into  a  scrap  \»>\. 
Scrap  is  later  ground  up,  blended  with  new  material,  and 
used  for  molding  smaller  parts. 

Such  parts  as  hood  release  handles  are  formed  in  injec- 
tion molds  having  numerous  cavities  (sixteen  for  tlu  ~e 
handles)*  When,  as  in  this  instance,  some  section^  «f 
molding  are  quite  thick,  cooling  is  expedited  by  submerging 
the  gate  of  moldings  in  cool  water.  This  makes  it  po^-ihle 
to  cut  the  castings  from  runners  more  quickly  and  reduces 
the  cycle  time  about  30%,  as  the  molds  can  be  opened  some- 
what sooner. 

Among  the  large  injection  moldings  are  radio  grilles  pro- 
duced for  Ford  cars  from  a  "silver  sand"  and  blue  metallic 
colored  plastics  in  a  45-second  cycle,  two  section-,  at  a  time. 
These  moldings  are  quite  large  and  have  a  boxv-shaped  .-eo- 
tion  so  that  a  mold  with  an  irregular  parting  is  used.  Push- 
out  pins  eject  the  molding  as  the  die  opens,  and  the  piece 
is  lifted  out  and  submerged  in  water  to  cool.  During  the 
next  cycle,  the  operator  cuts  off  the  sprue,  leax  ing  the 
molding  almost  ready  for  assembly. 

Except  for  Stokes  machines,  only  two  of  which  are  used 
for  small  minor  parts,  all  compression  and  tran-fer  mold- 
ing is  done  in  large  multiple-cavity  molds  equipped  with 
strip  or  cartridge  heaters.  Thus,  although  cycles  are  rela- 
tively long,  the  output  per  machine  and  per  operator  is  kept 
high.  The  cycle  is  shortened  as  much  as  possible  by  using 
preforms  that  are  preheated,  in  ovens  or  by  electronic 
means,  to  as  high  a  temperature  as  is  feasible,  and  by  using 
loading  frames  where  they  save  time. 

.Most  of  the  large  compression  and  transfer  moldings  are 
complex  parts  with  numerous  inserts,  and  many  require 
molds  with  loose  or  split  portions  that  have  to  be  taken  out 
during  a  part  of  each  cycle  to  free  the  moldings  and  add 
inserts  or  both.  Despite  this,  and  the  need  for  help* 
some  jobs,  some  cycles  are  held  to  3  min.  Preheating 
usually  raises  temperatures  to  about  220°  F  when  done  in 
ovens  with  infra-red  lamps  or  to  about  300°  F  when  high- 
frequency  electronic  heaters  are  used. 

A  typical  compression  molding  job  is  that  perform' 
Ford  V-8  distributor  coil  housings  done  in  a  21 -cavity 
mold.  For  this  job,  two  preforms  1"  thick  and  3"  in  diam- 
eter are  used  per  cavity  and  they  are  electronically  pre- 
heated on  a  loading  tray  which  is  made  the  bottom  electrode 
in  the  Thcnnex  preheater,  where  they  remain  ll/j  min. 
and  attain  a  temperature  of  300°  F.  When  the  preforms 
attain  the  desired  temperature,  the  current  is  shut  off  and 
the  tray  is  shifted  into  the  mold  and  the  slide  drawn  to  drop 
the  preforms  into  the  21  cavities. 

Because  of  this  pre-heat,  the  curing  time  (after  the  mold 
is  closed)  is  only  2l/j  min.,  as  against  6  min.  when  oxen 
pre-heating  was  used.  Two  men  per  press  are  used. 

In  molding  distributors  for   Ford  six-cylinder  cm 

itiM-iN  per  cavity  are  required  and,  as  the 
might  be  bent  or  displaced  if  straight  compression  molding 
were  used,  transfer  molding  is  chosen.    The  die  has  rjl 
cavities.      In    transfer    molding,    the    charge    is    first    pre- 
heated (using  an  electronic  preheater  and  preforms  wci^h- 
ing  Yt  Ib  per  cavity  or  a  total  of  3  Ib  for  this  mold)  and  is 
then  placed  in  the  injection  cylinder  which  is  on  top  of  and 
outside   the   mold   itself. 

As  the  charge  in  the  cylinder   i-  placed  undci 


II 


SKPTKMHKR  1916 


In  addition  to  manual  convenience,  the  famous  Thermex 
drawer  assures  precise  heating  and  a  steady  working 
pace  for  the  operator.  At  the  end  of  each  heating 
cycle,  timer  automatically  resets  to  zero.  Signal  light 
turns  off,  and  the  unit  is  ready  for  the  next  load. 


The  famous  Thermex  drawer  makes  possible  a  highly 
desirable  air  gap  between  material  and  electrodes. 
This  greatly  increases  uniformity  of  heat  in  non-uniform 
materials,  and  reduces  moisture  condensation  by  per- 
mitting proper  circulation  of  air  around  electrodes. 


The  famous  Thermex  drawer  provides  a  large  load 
area  which  permits  maximum  use  of  the  ability  of  high 
frequency  heat  to  uniformly  penetrate  masses  of  mate- 
rial. Drawer  holds  one  large  preform  or  many  small 
ones.  It  is  not  necessary  to  load  preforms  on  top  of 
each  other. 


Designed  around  the  famous  Thermex  drawer,  every 
Thermex  unit  for  the  plastics  industry  is  not  only  simple 
to  operate  but  also  simple  to  install.  Completely  self- 
contained,  Thermex  Red  Heads  can  be  easily  rolled 
into  position  and  from  place  to  place  as  needed. 


Designed  around  the  famous  Thermex  drawer,  com- 
pletely self-contained  Thermex  Red  Heads  do  a  big 
job  with  a  pronounced  absence  of  overall  bulk.  Every 
model  fits  into  present  press  layouts.  You  can  convert 
to  high  frequency  heating  without  upsetting  and  re- 
building your  plant. 


The  famous  Thermex  drawer— master  feature 
of  high  frequency  heating  for  plastics 


THERMEX  high  frequency  heating  equip- 
ment for  the  plastics  industry  is  dis- 
tinguished from  all  others  by  the  sliding 
drawer  heating  compartment.  This  master 
feature  is  the  key  to  many  THERMEX  fea- 
tures. All  told,  they  give  you  the  line  of 
high  frequency  heating  equipment  that's 
first  for  modern,  efficient,  self-contained 
material  handling  design. 

It's  the  most  complete  line  of  fully  de- 
veloped, convenient,  portable  high  fre- 
quency heating  units  for  plastics.  There's 
a  THERMEX  Red  Head  to  fit  your  needs. 


And  backed  by  the  experience  of  the  organ- 
ization which  developed  the  first  practica- 
ble industrial  high  frequency  dielectric 
heating  equipment,  every  THERMEX  Red 
Head  is  dependable. 

If  you're  going  to  convert  to  the  high 
frequency  preheating  of  plastic  materials, 
find  out  about  THERMEX  Red  Heads. 

Write  to  The  Girdler  Corporation,  Ther- 
mex Division,  Louisville  1,  Kentucky. 
District  offices:  150  Broadway,  New  York 
City  7;  228  North  La  Salle  Street,  Chi- 
cago 1;  1836  Euclid  Avenue,  Cleveland  15. 


The  First  Industrial  High  Frequency  Dielectric  Heating  Equipment 


THERMEX  snd  RED  HEAD—  7v«<fc  Uartt  Ren.  V  S.  Pat.  Off 


FIRST 
WITH  THE  MOST 
ADVANTAGES- 


/ 

|      The  Famous  Thermei  Drawer 
Dual  Timer  Control 
Portability 
Dependability 

Automatic  Signal  Light 
Automatic  Resetting  Timer 
Convenient  Working  Height 
Accessible  Control  Panels 
Large  Load  Area        ' 
Warp-  proof  Load  Tray 
Adequate  Metering 

Overload  -Under  load  Protection 
Automatic  Safety  Switches 
Air  Gap  with  All  Loads 
Rugged  Construction 
Compact  Design 
Heavy  Duty  Cabinet 
Economical  Use  of  Power 

SEPTEMBER  1946 


FLASTICS 


45 


V  8  distributor  housings  are  placed  singly  in  fixture  at 
right  for  removal  of  loose  core  ejected  with  molding.  Fix- 
ture at  left  prevents  dimensional  change  as  molding  cools 


Operator  is  removing  a  male  or  "force"  block  over  which  a 
distributor  has  been  molded.  Inserts  are  placed  in  each 
block  before  it  is  returned  to  mold.  Below,  phenolic  dis- 
tributor housings  are  being  taken  from  compression  mold 


by  a  ram  that  fits  the  hot  cylinder,  and  more  heat  is  added, 
the  charge  is  fluxed  and  is  forced  out  of  the  cylinder 
through  runners  that  enter  each  mold.  The  phenol  for- 
maldehyde used  is  of  a  grade  that  does  not  cure  rapidly; 
otherwise  some  of  it  would  cure  (harden)  before  the  cavi- 
ties are  all  filled  and  the  moldings  would  lack  proper  den- 
sity. But,  w  ith  the  plastics  chosen,  the  cavities  are  filled  with 
fluxed  resin  in  paste  form  before  curing  starts  and,  as  the 
resin  is  plasticized,  it  enters  the  cavities  slowly  and  fills 
them  without  displacing  or  distorting  the  inserts.  Pressure 
on  the  ram  places  the  softened  resin  in  each  cavity  under 
hydraulic  pressure.  In  the  cavities,  enough  heat  is  added 
from  the  mold  to  raise  the  temperature  further  and  to  effect 
a  cure.  As  the  contents  of  each  cavity  is  held  under  high 
pressure,  dense  moldings  of  excellent  dielectric  qualities  are 
produced. 

Filling  takes  only  30  sec  but  curing  requires  7  min.  with 
the  type  of  resin  used.  In  transfer  molding,  at  this  plant, 
the  mold  is  filled  at  one  press  and  then  is  shifted  along  a 
roller  conveyor  to  an  adjacent  press  where  curing  takes 
place.  There  are  three  molds  for  two  presses.  Molds  are 
used  in  rotation  and  the  one  that  is  not  in  the  press  re- 
ceives its  inserts  and  is  prepared  for  molding  while  the 
other  two  are  being  filled  with  plastics  and  subjected  to 
curing. 

When  the  mold  is  opened,  sections  of  it  containing  the 
distributor  moldings  are  removed  and  are  placed,  one  at  a 
time,  in  a  special  fixture  having  a  crank  that  removes  a 
loose  core  which  has  come  away  with  the  molding.  When 
thus  freed,  the  moldings  are  clamped  in  cooling  fixtures 
designed  to  prevent  distortion  and  dimensional  change  while 
cooling  proceeds. 

This  type  of  transfer  molding  is  rather  slow  but  it  makes 
possible  the  production  of  complex  moldings  that  could  not 
be  made  in  other  ways  and  also  avoids  the  displacing  and 
possible  breaking  of  inserts  which  would  be  likely  to  occur 
if  molding  with  powder  or  preforms  placed  directly  in  mold 
cavities  were  attempted. 

In  transfer  molding,  a  thin  flash  of  molding  compound 
remains  in  the  bottom  of  the  injection  cylinder  and  has  to 
be  removed  before  the  next  cycle  starts.  There  is  also  some 
waste  in  the  runners  that  carry  the  plastics  from  the  cylin- 
der to  each  mold  cavity  but  the  total  loss  is  not  large  and 
is  offset  by  the  advantages  mentioned  above. 

To  avoid  the  need  for  a  separate  injection  cylinder,  as 
commonly  used  in  transfer  molding,  Ford  is  just  putting 
into  use  a  variation  termed  "plunger"  molding.  In  this 
arrangement,  instead  of  using  a  separate  cylinder,  one  is 
built  into  the  mold.  The  bottom  of  the  cylinder  is  at  the 
mold  parting,  and  from  it  radiate  the  runners  for  feeding 
each  mold  cavity.  Thus,  the  mold  is  a  self-contained  unit, 
the  cylinder,  with  its  plunger,  being  part  of  the  upper  half. 

Instead  of  loading  preheated  preforms  into  a  separate 
mold,  these  are  set  in  a  recess  below  the  plunger  and  re- 
ci-ive  heat  from  the  mold  walls  as  fluxing  under  pressure 
proceeds,  and  the  liquid  plastics  flows  through  the  runners 
and  fills  the  mold  cavities.  When  the  mold  is  opened,  the 
flash  In-low  the  plunger  remains  in  the  parting  connected  to 
the  runners  and  is  broken  away  without  handling  a  separate 
cylinder.  Runners  are  somewhat  shorter  than  when  a  -cp- 
aiate  cylinder  is  used  and  there  is  no  sprue  from  cylinder 
to  runners,  as  the  latter  radiate  directly  from  the  cylinder 
bottom.  Since  less  handling  is  required,  a  somewhat  shorter 
molding  cycle  result-. 

At  present,  the  melamine  resins  are  used  only  for  tractor 
distributor  moldings,  largely  Ix-caiiM-  they  withstand  the 
weather  for  long  ]n-riods  and  have  lower  moisture  absorp- 
tion than  the  phenolic  and  furfural  resins.  I  he  latter 
adequately  for  ignition  system  parts  on  cars  and  trucks,  but 
the  melamine  resins  have  the  added  advantage  of  being  non- 
(Continucd  on  page  <><<  i 

46  SKPTKMHKK   1946 


PANELS   FOR 
FLUORESCENT    FIXTURES 

Because  they  understand  lighting  problems  thoroughly,  Yardley 
engineers  perfected  plastic  diffusion  plates  superior  to  glass 
in  many  respects.  Even  the  coldness  of  normal  fluorescence  can 
be  overcome  by  skillful  pigmentation. 

These  plastic  panels  are  dimensionally  stable  whether  extruded 
in  straight  or  curved  shapes.  Advantages  over  glass  include 
easier  handling,  lower  initial  cost,  lighter  weight,  simpler  pack- 
ing and  shipping. 


142  PARSONS  AYE. 


COLUMBUS  IS,  OHIO 


I«tr.d.r.  »f  SARAN.  CELLULOSE  ACETATE.  IUTYRATE.  POLYSTYRENE.  STYRALLOY  a.d  VINYLS.  AIM  1-j.ctlon   and  Completion   M«Mh«. 


SEPTEMBER  1946 


PLASTICS 


47 


R 


OUND 


ROUND 


EGS   in 


HOLES 


SQUARE  Pegs  m  SQUARE  Holes,  tool 


We  do  not  undertake  every  job 
offered  to  us  ...  because  we  don't 
aspire  to  become  square  pegs  in 
round  holes, — or  vice-versa. 


When  we  DO  accept  responsibility 
for  production,  you  can  be  sure  thai 
the  promise  of  satisfaction  fits  per- 
fectly with  our  capacity  and  skill. 


Our  experience  in  Plastics  dates 
back  to  World  War  I,  and  our 
growth  has  kept  pace  with  the  swift 
development  in  that  fertile  field.  It 
is  also  interesting  to  note  that  the 
businesses  we  serve  have  a/so  ex- 
panded— and  turn  to  us  for  their 
Quality  production. 


write  for  details  to 
MOLDING  DIVISION  of 


ore  PLASTIC 


MORE 

EYE-APPEAL 
FOR    GREATER 
BUY-APPEAL! 


* 

SEAMLESS 

if 

SHATTERPROOF 

* 
FEATHERUTE 

•k 
COLORFUL 


CLEARSITE  enhances  the  mer- 
chandising of  sanitary  goods, 
drugs,  toys,  machine  parts,  tools, 
sporting  goods  and  a  host  of 
products  that  deserve  better 
appearance  and  protection. 


Label-imprinting    is    part    of    the 
manufacturing  process. 


CLEARSITE.— 
the  Safety  Base 
Plaitic. 


Write  to  Container  Division 


CELLIIPLASTIC  CORPORATION 


OR  P. 


PLASTIC    CONTAINERS 


PLASTIC    PRODUCTS 

46     AVENUE    I  NEWARK    5.  N.  J. 

rotg  otnci  —  tto  nun  AVINUI  wrsr  COAST     CONTAINIR    SIRVICI   COMPANY.  IDS  ANGIUS   :r   CAI 


Ft.ASTtCS 


SKPTKMKKR   l!>n; 


Drawings  by  Julian  Krupa.  fJasllCS  Art  Sta« 


A  Presentation  of  the  Potential  Applications  of 
Plastics  as   Visualized  by  Industrial    Designers 

( lilsliCX  welcomes  designers'  contributions  to  this  department) 


BHl 


SSO.BDAT 


SEEEDBDfflT.. 


SHELTEbL- 


CARIQP 


Ingenious  adaptations  of  the  "Plastiboat"  hull 
utilize  a  single  mold  which  produces  all  of  the 
hulls,  cabin  tops,  etc.  The  development  provides 
interesting  possibilities  for  the  vacationist, 


TRAlLEiR 


tourist,  and  sportsman,  in  a  unit  which  is  easily 
transportable  and  is  described  as  possessing  the 
additional  advantages  of  being  leakproof  and  worm- 
proof,  hard,  tough,  durable,  and  reasonably  priced 


Atter  3'2  years  internment  camp  use.  plastics 
card*  have  retained  resiliency  and  snap.  Con- 
trast with  new  deck  shows  only  worn  printing 


A  New  Deal  for  Card  Players 

Tough  playing  cards  made  from  cellulose  nitrate  sheet 

will  far  outlast  decks  of  ordinary  cards/  and   they  can 

he  made  "new"  again  by  washing  with  a  damp  cloth 


'/ 


m 


Remrch  &  Development   Engineer 
Cruvcr  Manufacturing  Co. 


PLAYING  cards  made  of  plastics  date  back  to  the  early 
1900's  when  the  old  Celluloid  Corp.  dreamed  up  the  idea 
and  had  a  local  manufacturer  run  several  decks.  These  decks 
were  gilt  edged  with  a  glossy,  smooth  finish,  which  was  ob- 
tained by  press  polishing  the  cards.  However,  as  the  sheets 
were  quite  translucent,  the  character  spots  showed  through 
from  the  reverse  side,  making  it  easy  for  a  player  to  read  his 
opponent's  hand,  and  the  project  was  dropped.  The  next 
development  occurred  about  1935  when  an  Austrian  inven- 
tor made  cards  from  opaque  sheets,  and  thus  the  successful 
plastics  playing  card  was  born. 


50 


Cruver  Manufacturing  Co.  started  work  on  this  project 
in  the  middle  thirties,  using  a  cellulose  nitrate  stock  with  a 
pigment  content  which  produced  a  white  sheet  20"  by  25" 
with  satisfactory  opacity.  The  nitrate  sheet  was  selected 
over  all  other  materials  because  of  its  superb  physical  prop- 
erties. Its  excellent  resilience  and  snap  give  long  wear  to 
ranis  \\ithout  the  fraying  of  edges;  its  excellent  compati- 
bility with  printing  inks  insures  a  good  printing  job;  ami  it- 
good  dimensional  stability  makes  for  uniform  cards.  Its  lo\\ 
water  absorption  (approximately  .09%  on  24  hr  immer- 
sion) is  very  important  as  it  prevents  the  cards  from  warp- 
ing in  humid  weather  and  allows  them  to  be  completely 
submerged  in  water  while  being  washed.  All  of  these 
properties  add  up  to  a  material  unsurpassed  for  playing 
cards.  Our  present  suppliers  «i  this  stock  are  Celanese 
I  Mastics  Corp.,  E.  I.  du  Pont  de  Ncmours  &  Co.,  and  Nixon 
Nitration  Works. 

Hri'orc  printing,  rigid  inspection  °f  tnc  sheets  for  dust 
spots,  unevenness.  pin  point  holes  and  all  otlicr  irregularities 


SEPTEMBER  1946 


eliminates  approximately  25%  of  the  sheet  stock.  The  print- 
ing is  done  by  the  conventional  lithograph  process.  Here 
great  care  is  given  to  the  printing  inks  from  the  standpoint 
of  their  compatibility  with  the  nitrate  sheets,  their  color 
density,  drying  time,  and  color  fastness.  The  actual  printing 
is  done  by  running  one  color  at  a  time  with  each  color 
requiring  perfect  register.  The  perfection  and  complexity 
of  this  operation  can  be  illustrated  in  our  Persian  Prayer 
Rug  design,  which  requires  nine  trips  through  the  press, 
three  on  the  face  side  (red,  yellow,  and  black)  and  six  on 
the  reverse  side  (yellow,  red,  dark  blue,  light  blue,  pink,  and 
dark  red).  Each  color  must  pass  a  rigid  inspection  after 
each  run. 

Protective  Lacquer  Coating 

The  printing  of  the  cards  is  followed  by  the  application 
of  a  lacquer  coating,  which  serves  to  protect  the  ink,  thus 
giving  greater  wear,  and  to  give  a  pebble-grained  effect  to 
prevent  excessive  slipping.  The  sheets  are  mechanically 
sprayed  with  a  nitrate  lacquer  having  a  high  solids  content 
and  run  through  a  tunnel  oven  which  is  maintained  at  a 
constant  temperature.  They  are  then  inspected  and  sub- 
jected to  the  lacquer  tests  against  five  kinds  of  wear,  as 
follows:  (1)  abrasion  test  dropping  measured  amounts  of 
powdered  flint  from  a  fixed  height;  (2)  abrasibn  test  using 
the  Taber  abraser;  (3)  rubbing  test,  done  with  a  recipro- 
cating machine  under  5  Ib  weight  with  a  back  and  forth 
motion  (our  minimum  standard  is  365,000  rubs  to  bring 
about  failure)  ;  (4)  shuffling  test,  which  is  done  to  test  the 
edge  of  one  card  abrading  against  the  finish  of  another; 
and,  finally,  (5)  the  cards  are  tested  against  human  perspira- 
tion. 

Wax  is  Applied 

After  the  lacquering,  the  printed  sheets  are  waxed  with 
a  special  grade  of  natural  wax  that  is  obtained  from  the 
tropical  palm  trees  of  Brazil.  This  particular  wax  was 
chosen  for  its  three  outstanding  physical  properties,  namely  : 
(1)  it  is  a  very  tough  wax,  difficult  to  break;  (2)  it  breaks 
with  a  clean  fracture;  and  (3)  it  has  a  higher,  harder 
melting  point  than  commercial  wax  has.  The  wax  is  ap- 
plied in  a  hand  operation,  each  sheet  receiving  a  coat  on 


Oscillating  sprayers  spread  on  an  even  coat  oi  lacquer 
to  protect  the  ink  and  to  form  a  pebble-grained  surface 

each  side.  This  wax  protects  the  card  surface  in  much  the 
same  manner  that  a  liquid  floor  wax  protects  the  surface  of  a 
floor  from  scuffing  and  scratching. 

Blanking,  which  is  the  next  step  after  waxing,  has  proved 
quite  difficult  because  of  the  shrinkage  of  the  nitrate  stock. 
This  condition  is  primarily  due  to  insufficient  seasoning  of 


Lacquered  cards  emerge  at  the  end  of  an  arch-shaped  drying  tunnel  in  which  infra-red  lamps  dry  the  lacquer.  At  right, 
cards  are  individually  blanked  with  very  sharp  dies  so  that  tiue  edges  with  no  concave  dip  in  the  sides  are  obtained 


SEPTEMBER  1946 


PLASTICS 


51 


Culminating  inspections  made  at  various  stages  of  manu- 
facture, the  finished  playing  cards  are  closely  examined 
for  cleanliness,  clarity  of  ink.  and  trueness  of  pattern 


Having  com*  from  the  Inspection  room  already  wrapped 
In  cellophane,  twin  decks  are  packed  In  one  of  three  types 
of  colorful  acrylic  or  cellulose  acetate  butyrate  boxes 


the  sheet  stock  and  to  the  lacquer,  which  bites  into  the  sheet 
stock.  Another  pitfall  in  this  operation  i-  obtaining  the  fine 
edge  required  on  all  finished  decks.  This  edge  must  be 
absolutely  true,  with  no. concave  dip  in  the  sides.  It  must 
l>e  perfectly  smooth,  as  rough  edges  increase  wear.  This 
problem  was  overcome  after  many  months  of  experimenta- 
tion by  using  a  method  similar  to  the  one  used  by  the  alarm 
clock  manufacturers,  and  that  is  individual  blanking  with  a 
t  \\o-.stage  die. 

Defective  Cords  Arc  Removed  and  Replaced 

Final  inspection  is  done  in  a  dirt-free,  well-illuminated, 
quiet  room,  where  each  card  is  in>pected  for  four  types  of 
defects:  (1)  dust  and  dirt  spots,  which  are  most  common 
and  very  hard  to  control;  (2)  lack  of  clarity  and  brilliance 
nf  the  printing  inks,  particularly  of  the  reds;  (3)  fault  iness 
of  pattern,  or  imperfect  register  of  colors;  and  (4)  dark 
spots  on  the  back  side  of  cards  caused  by  uneven  sheet  stock. 
All  defective  cards  are  weeded  out  and  suitable  replacements 
are  made.  This  final  inspection  climaxing  a  whole  scries  of 
checks  after  the  various  phases  of  operation  gives  a  thorough 
control  over  all  the  processes  involved. 

Packaging  is  done  by  wrapping  each  individual  deck  in 
cellophane  (during  the  war  glasene  paper  was  used)  and 
hermetically  -sealing  out  all  dust  and  dirt.  Single  decks 
are  packed  in  a  conventional  cardboard  box,  in  the  Verona, 
a  box  made  from  cellulo.-c  acetate  butyrate,  or  the  Deluxe 
Cloisonnee,  a  methacrylate  box.  The  latter  two  are  by  far 
the  most  popular. 

Three  types  of  boxes  are  used  for  twin  decks,  all  molded 
of  plastics:  (1)  the  standard  streamlined  box;  (2)  the 
I  >eluxe  1  >ragon  box,  which  comes  in  either  a  jet  black  or 
an  ivory;  and  (3)  the  Deluxe  methacrylate  box.  The  first 
two  are  made  from  cellulose  acetate  butyrate.  The  Deluxe 
I  >ragon  box  is  a  replica  of  a  jade  jewel  box  owned  by  the 
Mahragin  of  India.  C.  L.  Cruver,  president  of  the  company, 
saw  the  possibilities  of  the  design  and  had  an  engraver 
make  a  duplicate  model.  This  model  has  had  such  wide 
acceptance  that  many  requests  have  been  received  for  an 
extra  Dragon  box.  The  Deluxe  methacrylate  box  is  made 
up  by  a  three-dimensional  color  work  called  l>a-  relief.  The 
cards  themselves  are  available  in  three  standard  designs — 
Modern  Classic.  Jewel,  and  Oak  Leaf — and  two  deluxe 
designs.  Persian  1 'raver  Rug  and  Dresden  Doll. 

Plastics  Cards  Can  Take  "ft" 

The  outstanding  merit  of  plastics  playing  cards  is  their 
lung  \\earability.  By  conservative  estimate,  they  will  outla-t 
50  decks  of  ordinary  cards.  A  recent  example  shows  how 
much  punishment  they  can  take.  After  two  years  of  normal 
n-e.  twin  decks  were  taken  into  an  internment  camp  in 
Shanghai,  where  they  were  used  almost  constantly  for  3}4 
years  for  solitaire  and  bridge.  The  printing  became  some- 
what worn,  hut  the  cards  still  shuffle  and  snap  and  have 
retained  the  thickness  of  the  original  sheet  stock.  (See 
photograph  on  page  50.) 

Another  important  advantage  is  washability.  Washing 
is  easy.  A  soft  cloth  or  cheese  cloth  is  dampened  and  rinsed 
thoroughly.  F.ach  card  is  then  wiped  front  and  back  with 
the  cloth  and  placed  on  a  soft  towel.  The  cards  may  be 
allowed  to  dry  unaided  or  they  may  be  patted  or  wiped  with 
a  soft  cloth  or  towel.  One  caution  must  In-  observed,  and 
that  is  not  to  wash  the  cards  in  hot  water.  Washing  pro- 
longs the  Usefulness  of  plastics  cards  by  removing  dirt  and 
other  foreign  matter  that  act  as  abrasives  on  the  surface 
of  the  cards  and  cause  them  to  wear  sooner.  Normally, 
cards  require  washing  only  once  or  twice  a  year. 

Although  cellulose  nitrate  cards  sell  at  higher  prices  than 

the  ordinary  types  of  playing  cards  (twin  decks  plus  the 

containers  start  at  $".(K(i.  their  cost  per  game  or  per  hotii 

•  if  playing  or  however  their  service  may  IK-  figured  is  low 

:  -e  of  their  long  life.  KM> 


IT.iSTH   s 


SEM  i  MI:I:K  1946 


PRECISION -PROCESSED  REPLICAS 
OF  INTRICATE  HAND  MODELING 


The  set  of  To ni -Corks, 

herewith  illustrated,  was 

molded     for 

Maxusa  International 

Corporation. 


3s»v-?o»n 

he  9«nera|  «,|||,w   ,._  **    0 


This  Gallery  of  "Rogues" 

Ability 


a  i#t&*4  Example  of  Consolidated's 
Inject  Character  into  Plastic  Molding 


COMPRESSION 

molding 

INJECTION 

molding 

TRANSFER 

molding 


These  colorful  and  highly  polished  "Men  of  Distinc- 
tion" are  stoppers!  Corks,  cemented  over  the  studded 
extension  of  each  caricature,  qualify  the  subjects  as 
protectors  for  opened  bottles  of  catsup,  vinegar, 
beverages,  etc. 

Toni-Corks,  injection  molded  of  Styrene  material, 
do,  thru  careful  mold  design,  faithfully  portray  the 
individual  and  varied  facial  expressions  created  by 
the  sculptor. 

The  assignment,  though  one  of  simple  molding 
procedure,  serves  to  highlight  Consolidated's  skill  at 
producing  quality  ...  in  quantity.  Our  know-how 
with  plastic  materials,  mold  construction,  and  mold- 
ing processes  —  stands  ready  to  custom-serve  product 
designers,  and  manufacturers.  Inquiries  invited! 


onsolidated 


MOLDED   PRODUCTS  <04/KttiU 

309     CHERRY     STREET,     SCRANTON     2.     PA. 


NEW  YORK    •    CHICAGO    •     DETROIT    •     BRIDGEPORT    •    CLEVELAND 


SEPTEMBER  1946 


PLASTtCS 


53 


Solution   of   cotton   linters,   extruded   around   mandrels   into 
chemical  bath,  produces  cellulose  casings  in  tubular  shape 


Alter   wash  ng  and  softening,  casing  is  put  through  drying 
machine,  emerging  as  Hat  tube  which  is  then  wound  on  rolls 


Plastics  "Franks"  are  Edible 

Regenerated  cellulose,  used  as  covering  for  ever-popular 
sausage  products,  protects  and  preserves  flavor  of  meat 


Sales   Promotion    Manager 
Vijking    Corporation 


EACH  year,  according  to  tin-  American  Mr;it  Institute. 
more  than  2.500,000,000  Ib  of  sausage  are  consumed 
in  the  United  States.  To  the  statistically  minded,  this  rcp- 
resents  about  19  Ib  of  sausage  for  every  man,  woman, 
and  child  in  the  country,  ami  about  one-eighth  of  our  entire 
meat  production.  And  plastics  has  an  important  part  in  this 
production. 

Sausage,  in  its  do/ens  of  varieties,  requires  a  casing  in 
which  ill--  iiu-at  and  other  ingredients  may  be  stuffed.  In 
this  country,  with  its  tremendous  demand  for  sandwich 
rncats.  enormous  c|iiantitics  of  these  rasing-  are  used.  I »i 
frankfurters  alone,  -VO.IMN)  miles  of  rasing  are  needed  yearly. 

There  are  two  types  of  casing — animal  and  cellulose. 
Animal  casing  is  made  of  the  small  intestine  of  shr,-p,  the 
large  and  small  intestine  of  hogs,  and  the  intestines,  ap- 


pendix,  bladder  and  gullet  lining  of  cattle.     Most  -lic<  ; 
ings  are  ini|x>rted;  but  even  the  supply  of  these,  and 
casings,  which  we  have  been  able  to  import  in  normal  yeai  s. 
has  fallen  far  short  of  the  requirements  of  the  san-.ige  in- 
dustry.   The  result  is  that  if  it  were  not  for  artificial  cas- 
ings,  shortages  would  have  forced  food  prices  considciahly 
higher  without  materially  adding  to  the  supply  of  c.i-mgs 
available   for   sausage   production. 

i  .  llnl.iM-  casing*  are  the  products  of  a  complex  chemical 
pi-oce^.  1- sM'iitially,  they  are  regenerated  cellulose  with  a 
softening  agent,  usually  glycerine.  Similar  to  cellophane 
in  ap|N-arance.  they  differ  from  it  in  many  important  rr- 
-IN-CN  which  aiise  from  the  different  and  more  strenuous 
M-r\ur  conditions  which  casings  must  withstand.  'I  h> 
made  from  the  finest  raw  materials,  the  principal  01 


PI.. 1ST  1 4'S 


SKI'TKMMKK   l!«lfi 


& 

...a  spring  service  you'll  like 


long  experience... 

in  applying  the  right  spring 

to  assure  top  performance 


L 


SEPTEMBER  1946 


your  effort  to  make  a  better  product  you  naturally 
try  to  leave  nothing  to  chance.  We'd  like  to  suggest  that 
you  don't  leave  the  springs  for  your  product  to  chance  either. 
Take  advantage  of  Accurate's  long  experience  ...  be  sure 
.  .  .  by  letting  us  help  you  choose  the  proper  type  and  size  spring, 
made  from  the  material  best  suited  to  your  conditions.  Many, 
many  times,  proper  spring  selection  has  paid  dividends  by 
improving  product  performance  and  preventing  product  failure. 

Accurate's  business  is  to  furnish  precision  springs  and 
wire  forms  for  a  wide  variety  of  products.  In  addition  to  our 
ability  to  help  you  with  spring  engineering,  we  have  the 
expert  personnel  and  modern  equipment  necessary  to  give 
you  fast  service  and  fine  workmanship. 

Send  for  a  copy  of  the  Accurate  Handbook  on  Springs. 

ACCURATE  SPRING  MFG.  COMPANY 

3828  W.  Lake  Street,  Chicago  24,  Illinois 


"TV cue 


PLASTi CS 


55 


Before  being  placed  in  drying  unit,  the  newly  extruded 
casings  are  inflated  with  warm  air  to  expedite  process 


which  is  cotton  linters.  The  manufacturing  processes  are 
designed  to  assure  maximum  strength  and  toughness,  and 
great  care  is  taken  to  avoid  damage  and  to  detect  and  elim- 
inate any  defects. 

Introducing  cellulose  casings  at  the  Yisking  Corp.,  Chi- 
cago, cotton  linters  are  subjected  to  a  chemical  process  ' 
until  they  become  liquid.  This  solution  is  extruded  through 
annular  dies  and  around  mandrels  into  chemical  solutions 
which  first  harden  the  material,  then  convert  it  to  cellulose 
in  tubular  form,  which  is  then  washed  free  of  all  traces  of 
chemicals  and  finally  passed  through  a  softening  bath.  The 
process  is  carried  out  on  large,  very  long  machines  of  spe- 
cial construction,  which  are  enclosed  in  order  to  secure  uni- 
form conditions  and  to  prevent  escape  of  chemicals  and 
fumes.  The  wet  tubing  is  finally  put  through  an  ingenious 
dryer  in  which  the  temperature  and  humidity  an-  clo>ely 
controlled  while  the  casing  is  maintained  at  constant  infla- 
tion pressure  and  longitudinal  tension,  finally  emerging  as  a 
llat  tulx;  which  is  wound  on  rolls.  Frankfurter  easing-  are 
then  shirred  in  order  to  simplify  ultimate  stuffing. 

A  number  of  factors  contributed  to  the  adoption  of  the-e 
cellulose  casings,  not  least  of  which  was  scarcity  and  un- 
certainty of  supply  of  animal  casings.  Animal,  or  natural, 
casings  are  difficult  and  expensive  to  clean.  They  vary 
greatly  in  size  and  quality ;  even  after  sorting  and  grading, 
the  variance  is  apt  to  be  relatively  great.  And  they  present 
problems  of  preservation,  transportation  and  storage. 

Because  of  these  and  other  difficulties,  a  search  for  a  sat- 

i-factory  substitute  for  animal  casings  was  carried  on  for  a 

numl>er  of  years.    Finally,  in  1926,  success  was  attained,  in 

the  production  of  casings  made  from  regenerated  cellulose. 

(Continued  on  page  93) 


"Shirring"  ol  ca*lng*  lor  skinless  frankfurters  simplifies  the  ultimate  stuffing  operation  making  It  possible  lor  an 
operator  to  handle,  with  ease,  considerable  length*  ol  the  tubing  shirred  by  machine*  Into  small,  compact  units 


56 


PLASTICS 


SKI'TKMHKR  1946 


For  Versatility  in  Plastic  Molding 

you  can  Depend  on  GRIGOLEIT 


For  19  years  we've  supplied  many  nationally 
prominent  manufacturers  with  parts  and  trim  for 
their  products.  The  versatility  of  our  facilities  and 
our  molding  experience  enable  us  to  create  unusual 
design  or  standard  plastic  items. 
For  reasonably  early  availability,  we  offer  an  ex- 
tensive "standard"  line  of  handles,  knobs  and 
other  parts  for  stoves,  furniture  and  household 


appliances;  also  a  large  "stock"  line  of  closures 
for  foods,  drugs  and  cosmetics. 
We  also  maintain  a  complete  custom-molding  serv- 
ice in  thermo-plastic  and  thermo-setting  plastics. 
Operating  our  own  metal  and  tool  shops,  we  are 
able  to  insure  perfect  blending  of  plastics  and 
metal. 

Write  for  1946  Catalog 


THE    GRIGOLEIT   COMPANY 


744    E.   NORTH    STREET  DECATUR    8O,   ILLINOIS 

SEPTEMBER  1946  PLASTICS  57 


Strikingly  unusual  bookend*  are  formed  ol  three 
thick,  highly  polished  pieces  ol  Rohm  &  Haas'  "Plex 
iglas"  giving  the  effect  ol  carved  crystal.  The 
House  ol  Plastics,  St.  Louis,  has  created  the  classic- 
ally dignified  yet  ultra-modern  design  that  empha- 
sizes the  sheer,  clear  beauty  ol  the  material  and  is 
planned  to  blend  with  today's  decorative  schemes 


durable,   flexible   and 
weight,   nylor 

combs  in  lour  styles  are  made 
by  Columbia   Proiolttosite  Co. 


fabricated  by  Emeloid  Co..  Inc..  from 
injection  molded  sections  ol  cellulose 
acetate,  a  well-designed  draining  rack 
for  dishes  is  useful  kitchen  accessory 


Clear  and  vat-dyed  dark  amber  acrylics  are 
combined  by  Dorian  Studio  ol  Hollywood  to 
make  a  good-lookinq  and  unusual  cocktail 
tray,  with  matching  ice  bucket  and  tongs 


.Me* 


• 


^** 


m 


Of  molded  polystyrene,  in  red,  white  and  blue,  a  I'l"  scale 
model  of  the  21'  Chris  Craft  speed  boat  is  made  by  the  Harvey 
Machine  Co.,  Inc.,  faithfully  reproducing,  in  miniature,  each 
detail  of  the  original.  The  18"  hull  is  injection  molded  in  one 
piece,  of  clear  polystyrene,  and  acrylic  forms  the  luminescent 
headlights.  The  model  runs  800'  on  a  wound  spring  coil  motor 


Lightweight  and  pliable,  protective  sleeves  of  fabric  coated 
with  vinyl  resin  are  included  in  The  B.  F.  Goodrich  Co.'s 
line  of  industrial  clothing.  Of  particular  value  to  those 
workers  whose  arms  require  protection  against  oils,  most 
acids  and  alkalies,  the  sleeves  are  between  16"  and  17"  long 


"Wataseal",  an  all-plastics  film  produced  by  Harte  &  Co., 
Inc.,  is  used  to  fashion  a  transparent,  smart-looking,  house- 
hold apron,  with  gay-colored  piping.  Among  the  advan- 
tages listed  for  this  material  are  its  strength,  resistance 
to  acid,  stains  and  dust,  and  its  quick,  easy  cleanability 


59 


Plastics  training  seat  for  baby  is  comfortable,  sanitary,  light- 
weight,  and   blends   with   color   scheme   of   any   bathroom 


Toilet  seats  of  polystyrene  are 
lightweight,  sanitary,  convenient 


Fingertip  pressure  is  sufficient  to  swing  the  "Cher-Chair" 
into  place  or  to  fold  it  unobtrusively  back  when  not  in  use 


Training  Seats  Use  Plastics 


ALWAYS  in  place,  yet  never  in  the  way — that  is  per- 
haps the  most  outstanding  advantage  of  Cher-Chair. 
•A  new  plastics  toilet  seat  for  balm's,  ju-t  introduced  by  the 
I  Hinrich  Company  of  Chicago. 

l>csigncd  by  a  young  father,  an  engineer  by  profession. 
who  was  constantly  annoyed  by  the  awkward  and  cunilier- 
somc  factors  of  the  wooden  devices  formerly  available,  this 
nt'w  training  seat  weighs  a  mere  \l/j  Ib  and  folds  into  a 
i-niivrniently  thin  and  unobtrusive  package.  Attached  to  tin- 
regular  toilet  seat,  the  Cher-Chair  folds  out  of  the  way  at 
the  tutich  "f  a  linger,  and  can  IK'  swung  back  into  place  with 
initial  case.  In  no  way  does  it  interfere  with  the  regular 
toilet  scat  or  lid:  yet  it  is  always  in  place  when  \\antcd. 

In  designing  this  seat,  the  first  problem  to  lie  met   was 
choosing  of  materials.     Since  warmth  was  of  great  impor- 
tance,   three    possibilities    presented    themselves:     tin 
could  IK-  made  of  wood,  of  rubber-coated  metal  or  of  pla-tir-. 

<  ..Moderation  of  WIKH!  was  abandoned,  N'cailsc  wood 
could  not  provide  the  strength  required  for  this  chair  and 
still  maintain  the  thinness  neces-aiy  for  the  unit.  Also, 
wood  had  to  l>c  painted  and.  in  time,  the  paint  wou'd  chip. 
•  splintered  and  could  not  lie  used  to  produce  the 
attiai -tin-  scat  which  the  manufacturer  hoftc.l  to  develop. 

Rubber-coated  metal  also  presented  many  disadvantages. 
It  was  a  more  expensive  process,  and  there  was  a  constant 


possibility  that  the  rublx-r  coating  might  flake  off.  A  rub- 
ber-coated metal  could  not  offer  the  sanitary  properties  ,M 
the  ease  of  cleanahility  that  parents  would  demand  in  this 
item,  nor  would  it  be  kind  to  Iain's  skin. 

Plastics  fulfilled  all  of  these  requirements,  plus  another 
highly  important  one — that  of  appearance.  The  great  vari- 
ety of  color  schemes  used  in  bathrooms  caused  \V.  J.  I  hum. 
the  designer  of  this  seat,  to  reason  that  a  colorless  material. 
blending  unobtrusively  with  any  bathroom's  color  scheme. 
would  be  most  desirable.  This  was  somewhat  contrary  to 
the  opinion  of  many  merchandisers,  who  felt  that  in- 
buy  pinks  and  bines  and  other  sbades  for  baby,  with  no 
thought  as  to  how  these  hues  affect  the  color  schemes  of 
the  home.  Ad\.mcc  sales,  however,  seem  to  licar  out  Dirm's 
opinion. 

"I  he  result   was  an  injection  molded  Cher-Chair  of 
polystyrene,    with    its    warm,    glistening,    smooth    M. 
There   were  many  other  plastics  which  might  also  have 
been  Used  for  this  purpose,  but  polystyrene  was  selected  !*• 
cause,  in  addition  to  jiosscssiuf;  ;ill  ,,f  the  necessar\  char.ic- 
tcristics,    it    was    relatively    inexpensive    and    more    readily 
available. 

There  are  four  plastics  jiarts  to  the  l  /irr-i  'lian 
the  arms  and  the  back-rest.     Supporting  the  arms  and  back 
rest  is  a  stainless  steel  wire  frame  which  is  safe  and  strong. 


60 


IT. \STI1  * 


SKITKMHKR  1946 


and  so  designed  that  it  does  not  come  in  contact  with  the 
baby's  skin.  Stainless  steel  fasteners  also  permit  the  Cher- 
Chair  to  be  slipped  onto,  or  removed  quickly  and  easily 
from,  any  style  adult  toilet  seat. 

A  rubberized  fabric  is  used  as  the  deflector  for  the  seat. 
It  had  originally  been  intended  to  use  a  clear  vinyl  sheeting 
for  this  purpose.  This  material  was  felt  to  be  preferable 
because  it  would  have  permitted  heat  sealing,  instead  of 
stitching  of  seams,  and  would  have  harmonized  perfectly 
with  the  rest  of  the  chair. 

All  vjnyls  and  similar  clear  plastics  sheetings  which  have 
been  available  to  date,  however,  are  manufactured  with  the 
use  of  a  plasticizer  known  as  dioctyl  phthalate.  Since  this 
chemical  causes  polystyrene  to  craze,  the  manufacturer  used 
a  white  rubberized  fabric  for  the  deflector. 

The  compactness  with  which  the  Cher-Chair  has  been  de- 
signed is  one  of  its  chief  selling  points.  The  entire  seat 
folds  neatly  to  a  maximum  thickness  of  }i".  Parents  trav- 
eling with  babies  will  appreciate,  too,  the  ease  with  which 
the  seat  slips  into  a  sturdy,  smartly  designed  carrying  case 
which  is  only  13"  high,  15"  wide  and  lj£"  deep.  Overall 
weight,  case  and  all,  is  only  2  Ib.  END 


Know  Your  Resin  Fibers 

(Continued  from  page  41) 


fundamental  characteristic  of  a  beater  dispersion  resin  is 
almost  complete  water  insolubility.  The  resin  may  be 
added  to  the  beater  as  a  finely  dispersed  solid  or  in  an 
emulsion  form  that  can  be  precipitated.  In  any  case  the 
resin  must  be  capable  of  being  filtered  out  with  the  pulp 
on  the  preforming  screen. 


Since  the  pulp-resin  preform  is  essentially  a  two-phase 
system,  its  properties  will  be  a  function  of  both  the  base 
resin  and  the  fiber.  At  present  tests  are  being  run  on 
various  types  of  fibers  including  unbleached  kraft,  un- 
bleached sulfite,  alpha,  defibered  rag,  ground  wood,  and 
waste  paper,  with  the  object  of  determining  the  effects 
of  pulp  types  and  fiber  sizes  on  the  finished  plastics.  Recent 
findings  have  indicated  that  strength  properties  are  not  de- 
pendent on  fiber  length  or  pulp-sheet  strength  and  that  me- 
chanical and  semi-chemical  pulps  are  suitable  for  pulp 
plastics,  although,  in  general,  these  plastics  are  inferior  to 
those  based  on  chemical  pulps. 

Although  general  conclusions  on  the  physical  strength 
properties  of  the  molded  pulp-resin  preforms  may  be  stated, 
it  is  not  justified  at  this  stage  to  draw  any  final  conclu- 
sions on  some  points.  This  is  particularly  true  in  view 
of  the  fact  that  strength  properties  will  depend  on  individual 
components  making  up  the  preform  system,  namely  fiber 
and  resin  types  in  addition  to  process  variables.  Other 
factors  are  also  introduced  such  as  preform  drying  and 
molding  conditions.  However  the  effects  of  these  are  min- 
imized by  the  fact  that  it  is  relatively  easy  to  control  them. 

The  results  of  a  series  of  studies  on  fiber  types  in  which 
unbleached  kraft,  unbleached  sulfite,  alpha  pulp,  defibered 
rag,  ground  wood,  and  waste  paper  were  tested,  have  in- 
dicated kraft  fiber  to  be  slightly  better  in  strength  prop- 
erties than  sulfite,  rag  or  alpha  pulp,  with  ground  wood 
or  waste  paper  being  quite  inferior.  There  are,  however, 
some  contradictory  results  that  have  to  be  clarified  in 
further  tests,  on -the  dependency  of  physical  properties  on 
fiber  length.  From  a  processing  standpoint  there  is  an 
optimum  fiber  length  which  would  be  long  enough  to  give 


AUBURN  BUTTON  WORKS.  INC. 

FOUNDED   IN    1(76   •   AUBURN,  NIW  YORK 


AUBURN'S 

Plastics  Gallery 

Auburn  molded  plastics  have  served  American 
industry  for  the  last  70  years.  Auburn  "know- 
how"  is  the  product  of  that  experience  ...  it  is  the 
extra  value  you  get  when  you  choose  Auburn  as 
your  custom  molder. 


AUBURN    ENGINEERED   PLASTIC    PRODUCTS 

Compression,  Transfer,  and  Injection  Molding 
Automatic  Rotary  Molding  for  Moss  Production 
Extruded  Vinyl  or  Acetate  Tubes  and  Shapes 
Cellulose  Nitrate  Rods,  Sheets,  Molded  Ports 
Mold  Engineering  and  Complete  Mold  Shop 


SEPTEMBER  1946 


PLASTICS 


61 


K&J 
RINGS 
THE  BELL 

when  it 
comes  to 
molding 
service 

For  more  than  a  quarter  of  a  century  K&J 
has  solved  the  seemingly  impossible  in  mold- 
ings .  .  .  naturally,  improved  facilities  and 
techniques  have  augmented  this  experience. 

Whatever  your  molding  problem  involves 
.  .  .  material,  type  of  mold  or  molding,  put  it 
up  to  K  &  J. 

K  &  J  is  a  controlled  molding  service  re- 
sulting in  predetermined  satisfaction  in  every 
molded  piece. 

KUHN  &  JACOB 

MOLDING    &    TOOL    CO. 

1200     SOUTHARD     STREET,    TRENTON,     N.     J. 

TtUPHONC-niNTON  5391 


CONTACT 
IHf  K  I  J 


NIMKT   YOU 


•   C.  UUMAN,  44  W.  4SNO  ST..  NEW  TOM.  N.  T. 
mCPHONC-PCNN  1-034* 

TOWLI  4  ION  CO..  II  W.  CMlLTON  «vt.,  PHIL*.,  Pi 
TCLlPMONt- VICTOR  If 00 

WH   T.  WYIC*.  IOX  II*.  ITMTrOID.  CONN.. 
mtPMONC  .  ITRATrORD  t-441t 


IMPREGNATION     PROCESS 


BEATER    DISPERSION    PROCESS 


PRESSURE 
FELTING     UNIT 


PRE-SQEEZINC  * 
UNIT 


MOLDING  OPERATION 


Flow  sheet  on  preparation  of  fiber  resin  preforms 

good  felting  properties  and  not  too  long  to  produce  a  bulky 
preform.  Tin-  short  libers  of  ground  wood  or  waste  paper 
cause  processing  difficulties  insofar  as  they  tend  to  plug 
up  screen  openings  and  to  interfere  with  felting  operations. 

Studies  on  resin  ty)x-s  used  in  conjunction  with  kralt 
pul|i  have  led  to  some  interesting  conclusions.  It  has  l>een 
found  that  where  the  resins  penetrate  into  as  well  as  coat 
the  fiber  the  result  is  greater  dimensional  stability,  lower 
water  absorption,  and  lower  impact  strength.  Tims  a 
highly  |x>lar  water  solution  or  phenolic  resin  will  pene- 
trate into  the  liln-r  renters  resulting  in  a  more  dimension- 
ally  stable  product  than  can  IK-  obtained  with  a  less  |«>lar 
alcohol  solution.  On  the  other  hand,  the  alcohol  soluble 
phenolic  will  yield  a  higher  impact  strength  U-cau-c  of  the 
ability  of  the  unimprcgnated  fiber  centers  to  act  as  energy 
absorbers  for  an  impact  blow. 

Accompanying  tables  will  serve  to  illustrate  some  of  the 
physical  properties  of  pulp-phenolic  preforms.  The  molded 
pulp-phenolic  products  have,  in  general,  higher  strengths 
than  those  of  the  standard  molding  materials,  which,  l>csn!es 
their  ability  to  IK-  made  into  large  articles  with  very  thin 
-ect ions,  makes  them  very  interesting  materials  from  the 
molder's  stand|Miint. 

I  he  industry  is  not  st.itic.  It  is  proceeding  with  an  in- 
tensive program  of  the  evaluation  of  new  fibers  and  resins 
and  of  improvement-  in  process  techniques  ami  manufac- 
turing methods.  END 


Pl.ASTtCS 


SKITKMHKK  1946 


Vinyl  Insulation 

Produces  Better  Wiring 


.   O. 


Technical   Service    Engineer,   Geon   Thermoplastics 
B.  F.  Goodrich  Chemical  Company 


ONE  of  the  ways  in  which  plastics  will  help  supply  the 
greatest  demand  for  home  building  materials  that  has 
ever  existed  is  in  the  un-spectacular  but  important  role  of 
jacketing  and  insulation  for  building  wire.  Not  only  will 
the  footage  demand  be  tremendous  because  of  the  huge  num- 
ber of  houses  to  be  built,  but  more  wire  will  go  into  each 
house  than  heretofore  on  account  of  the  increased  use  of 
electrical  appliances  and  more  electrical  outlets. 

The  vinyls,  because  of  exceptional  properties  and  ease  of 
processing,  have  greatly  replaced  natural  and  synthetic  rub- 
ber in  this  use  within  the  past  five  years.  Especially  prom- 
inent in  the  wire  and  cable  industry  are  the  polymers  and 
copolymers  of  vinyl  chloride,  developed  before  and  during 
the  war  and  proved  on  battleship  and  on  battlefield. 

Flameproofness 

One  of  the  properties  that  gave  polyvinyl  production  such 
an  impetus  during  the  war,  when  it  was  increased  tenfold 
in  a  five-year  period,  is  flameproofness.  This  property  was 
'  so  important  to  the  Navy  that  today  over  80%  of  all  cable 
and  wire  on  naval  craft,  including  communications  and  con- 
trol cables,  radar  cables  and  power  cables,  has  insulation  or 
jacketing  of  polyvinyl  chloride.  By  the  same  token,  the 
polyvinyls  are  equally  of  value  for  house  wiring  in  view  of 
the  fact  that  the  second  largest  cause  for  fires  in  the  home 
is  faulty  wiring. 

Flameproofness  of  vinyl  chlorides  is  an  ability  to  be  self- 
extinguishing  or  to  prevent  the  propagation  of  flame.  There 
are  some  compounds  designed  for  use  in  extremely  low  tem- 
peratures, of  the  order  of  —  70°  C,  which  are  not  self- 
extinguishing  but  are  better  classed  as  "slow  burning." 
However,  most  materials  sold  for  wire  and  cable  use  and 
particularly  those  for  house  wire  are  self-extinguishing. 

Another  property  making  the  polyvinyls  outstandingly 
superior  is  their  excellent  aging  characteristic.  The  stand- 
ard aging  tests  such  as  the  Geer  oven  and  oxygen  bomb 
tests  are  no  longer  significant  with  vinyls  because  of  their 
resistance  to  ordinary  aging.  Tests  run  normally  on  ordi- 


Properties  of  Polyvinyl  Chloride  Insulation 


Property 


Value 


Tensile  strength  (psi) 1 ,500-3,000 

Elongation  (%) 1  50-400 

Modulus  at  100^  elongation  (psi) 500-1,500 

Tear  resistance  (Ib) 1  5-40 

Specific  gravity 1 .2- 1 .5 

Low  temperature  flexing  limits  (  C) 0-60 

High  temperature  operating  limits  CO 60-80 

Color NEMA  Standards 

Chemical  resistance  to  acids,  alkalies,  and  ordinary  solvents Inert 

Resistance  to  sun,  ozone,   and  ordinary  weather  conditions Excellent 

Oil  resistance Excellent 


Smooth  surface  of  insulation  makes  wire  easy  to  install, 
and  permanent   NEMA   colors  assure  quick   identification 


nary  rubber  compounds  for  7  to  14  days  require  a  run  of 
60  days  at  70°  C  on  vinyl  chloride  plastics  to  show  ap- 
preciable effects.  Even  after  60  days  at  70°  C,  the  tensile 
strength  may  be  absolutely  unaffected  and  the  elongation 
may  be  reduced  by  only  a  few  per  cent.  Ordinary  aging 
means  little  to  vinyl  resins  with  the  result  that  wire  insu- 
lated with  them  has  a  very  long  life. 

It  is  usually  not  possible  for  a  single  compound  to  have 
the  range  of  qualities  shown  in  the  table.  Plastics  com- 
pounds for  wire  use  are  compromises  designed  to  cover  the 
ra'nge  needed  for  a  particular  application  or  group  of  ap- 
plications. The  ranges  shown  in  the  table  are  those  for 
commercial  formulations.  For  special  purposes  they  may  be 
modified  to  obtain  emphasis  on  a  special  characteristic. 

There  has  been  no   sacrifice  of  electrical   properties  to 


SEPTEMBER  1946 


PLASTICS 


63 


use  thinner  walls  are  possible  on  non-metallic  sheathed   cable   insulated   with   polyvinyl   chloride,   smaller   holes   in 
tudding  can  be  used.    Either  a  plastics  or  rubber  extruder  can  be  used  in  applying  polyvinyl  chloride  insulation  to  wire 


Coaled  wire  pass**  through  two  annealing  units  and  enters 
cooling  trough.    On*  unit  is  open  to  show  Its  construction 


obtain  the  outstanding  physical  properties  described  above. 
On  the  contrary,  the  polyvinyls  possess  such  a  high  dielec- 
tric strength  that  it  has  been  possible  to  use  thinner  walls 
of  insulation.  This  in  turn  has  meant  a  decrease  in  the 
overall  weight  of  the  wire  and  a  cutting  down  on  the 
space  required  by  each  wire.  It  is  therefore  possible  to 
carry  a  greatly  increased  number  of  conductors  in  a  given 
size  of  conduit  and  hence  greater  power  in  the  conduit. 

The  insulation  resistance  of  these  materials  is  now  com- 
parable to  that  of  the  better  grades  of  natural  rubber  in- 
sulation. However,  their  insulation  resistance  is  affected 
by  temperature  changes,  and  gradually  decreases  with  rise 
in  temperature. 

In  considering  the  above  properties,  we  have  seen  why 
the  polyvinyls  are  slated  to  find  such  a  wide  place  in  the 
insulation  and_  jacketing  of  house  wire,  generally  known  as 
T  wire.  Another  property  making  it  equally  useful  on  TVV 
win-,  which  is  house  wire  approved  for  wet  locations,  is 
the  ability  to  be  immersed  in  water  for  long  periods  of  time 
without  any  appreciable  change  in  its  electrical  properties. 
A  commercial  testing  laboratory  which  tested  insulation 
made  from  Geon  (polyvinyl  chloride)  by  immersing  it  in 
water  for  106  days  at  70°  C  (158°  F)  found  very  little 
change  in  electrical  properties  after  this  severe  test.  \c- 
cordingly,  TW  wire  inflation  made  from  (icim  has  been 
approved  by  the  Underwriters  Laboratories  tor  use  m  wet 
locations  without  lead  sheathing.  Its  flameproofness  is  also 
important  here,  where  exposed  connections  increase  the 
danger  of  short  circuit  and  fire,  and  so  is  its  resistance  t» 
the  action  of  acids,  alkalies,  oil,  greases,  mildew,  and  many 
other  normally  destructive  factors  present  in  the  type  of  in- 
stallation in  wet  locations  \\here  corrosive  conditions  ;m- 
common. 

The  applying  of  polyvinyl  chloride  to  wire  is  readily 
adaptable  to  any  plant  equipped  with  either  a  plastics  or  a 
rubber  extruder.  NVhile  the  latter  is  naturally  less  advan- 
tageously employed  than  the  specially  designed  plastics  ex- 
truder, it  can  be  made  quite  satisfactory  for  use  with 
tics  by  a  few  minor  changes  in  the  process. 

The  rnlil><T  extruder  differs  fundamentally  from  the  pla-- 
tie-  extruder  in  that  the  former  ha-  a  relatively  short  liar- 


!•  I.  .1 .«  T  I  <  S 


-KriKMHKK    1'Mi; 


YOU  HAVE  A 


DIFFICULT  PROBLEM 


INTERNATIONAL  PLASTIC   HARMONICA  CORPORATION  .  44  DICKERSON    STREET  .  NEWARK  4,  N.  J. 
1ER  1946  PLASTICS  65 


Ingenious  New 

Technical  Methods 


To  Help  You  with  Your 
Reconversion  Problems 


New,  Simplified  Drill  Press  Vise, 
Speeds  Up  Drilling,  Spacing,  Milling 


Designed  to  be  used  with  a  drill 
press  (able  having  either  parallel 
or  radial  slots,  the  New  UNI- 
VISE  drill  press  vise,  with  guide 
bar  and  protractor  disc,  speeds 
up  and  simplifies  drilling,  layout 
and  spacing  work  in  straight 
lines,  radial  or  circular.  With  two 
movable  jaws,  vise  has  universal 
movement  without  swinging 
table  or  head  of  drill  press  to 
locate  exact  position  of  work. 
Operator  thus  adjusts  work 
quickly  for  accurate  registration. 

Guide  Bar  facilitates  drilling 
holes  in  a  straight  line.  With  a 
straight  edge  and  a  lineal  scale 
on  surface,  it  registers  with  lineal 
scale  of  vise.  Protractor  disc,  for 
drilling  holes  accurately  in  a 
circle,  has  parallel  slots  register- 
ing with  parallel  slots  in  base  of 
vise,  and  a  removable  means  to 
pivot  complete  unit  on  table  of 
drill  press. 

Accurate  work  can  always  best 
be  done  by  attentive  operators. 
That's  why  many  factories  urge 
workers  to  chew  gum.  The  chew- 
ing action  helps  relieve  monot- 
ony—helps keep  workers  alert, 
thus  aiding  them  to  do  a  better 
job  with  greater  ease  and  safety. 
And  workers  can  chew  Wrigley's 
Spearmint  Gum  right  on  the  job 
—even  when  hands  are  busy. 

You  can  gtt  complete  information  from 
Spiral  Mfg.  Corp.,  3612-26  N. 
Kilbaurn  At*.,  Chicago  41,  IU. 


rcl,  a  more  deeply  grooved  worm,  and  a  greater  clearance 
U-tween  the  worm  and  the  barrel. 

With  the  longer  barrel  of  the  plastics  extruder,  indicated 
granular  polyvinyl  chloride  can  be  fed  into  the  barrel,  where 
it  is  >lowly  conveyed  by  worm  action  to  the  die  under  grad- 
ually increasing  temperatures.  By  the  time  it  travels  the 
length  of  the  long  barrel  and  is  about  to  enter  the  die,  it 
has  become  plastic  and  has  a  temperature  of  375"  !•'. 

However,  in  using  the  rubber  extruder  with  its  shorter 
barrel,  it  is  necessary  to  take  the  additional  step  of  pre- 
warming  the  compound  before  placing  it  in  the  extruder 
barrel  in  order  that  the  same  375°  F  temperature  i>  reached 
at  the  die.  This  prc-warming  is  done  on  a  steam  heated 
mill  to  a  temperature  of  270-300°  F. 

In  \\  plastics  extruder,  a  breaker  plate  in  combination  with 
one  or  more  fine  mesh  screens  is  used  between  the  end  of. 
the  worm  and  the  head  chamber.  This  is  to  insure  that  the 
material  is  in  a  plastic  state  before  it  enters  the  head.  Rec- 
ommended screens  on  a  plastics  extruder  arc  two  of  30 
meshes  per  inch  or  one  20  and  one  40,  fabricated  from 
stainless  steel  or  monel  metal. 

Because  the  large  clearances  of  the  worm  in  rubber  ex- 
truders do  not  force  plastics  through  the  very  fine  screens 
ordinarily  employed  on  a  plastics  extruder,  somewhat 
coarser  screens,  such  as  a  combination  of  a  10  and  20  mesh, 
must  be  used  on  a  rubber  extruder.  It  is  interesting  to  note 
that  the  barrel  of  a  rubber  extruder  does  not  have  to  be 
specially  coated  when  converted  to  the  extruding  of  poly- 
vinyl  chloride  materials. 

Some  conception  of  the  potential  market  for  T  and  T\V 
IK.IIM-  wire  in  an  annual  1,260,000  home  building  program 
can  be  reached  with  an  estimate  of  approximately  2000  as 
the  footage  required  in  the  average  house.  Two  thousand 
feet  times  the  required  1,260,000  homes  totals  more  than 
two  and  a  half  billion  feet,  which  will  be  the  amount  needed 
per  year  on  urban  home  building  alone.  To  this  volume 
must  be  added  the  footage  that  will  be  required  in  a  large 
commercial  building  program  and  rural  home  building. 

The  above  figures  are  for  T  and  TW  wire  only.  In 
addition,  there  will  be  a  tremendous  footage  required  for 
telephone  wire,  fixture  wire,  radio  wire,  lamp  cord,  and 
appliance  cord. 

(ii-i'ii  plastics  will  be  used  as  insulating  material  on  all 
of  the  above  types  of  domestic  wiring  with  the  exception  of 
cord  for  certain  types  of  heating  units  such  as  toasters, 
in  >n-.  or  home  heaters.  There  is  reason  to  believe  that,  with 
developments  coming  as  fast  as  they  are,  even  those  applica- 
tion may  soon  be  on  the  li-t.  t  M> 


In -Plant  Molding 
(Continued  from  page  46) 


AA-84 


tracking,  that  is,  they  do  not  form  a  carbon  path  from  arc- 
ing. 

Most  of  the  compression  molding  jobs  require  molds  SO 
costly  and  a  technique  so  exacting  that  few  molding  shops 
would  undertake  the  work  even  where  they  have  presses  of 
adequate  size  or  adapted  for  the  purpose.  In  many  • 
>p«vial  equipment  for  holding  moldings  while  they  cool  is 
used,  and  nut  a  few  molding-  undergo  machine  operations  t,, 
form  undercuts,  cut  through  inserts  or  hold  particular 
dimensions  closer  than  molding  practice  alone  permit-. 

Moldings  for  Ford  cars  are  made,  of  course,  in  largest 
numU-rs,  but,  in  addition  to  those  for  Ford  trucks  anil  trac- 
tcirs  and  many  for  service  requirements,  molding*  foi  Mer- 
cmy  and  for  Lincoln  cars  .ire  produced  also.  The  setup  in 
each  cast.'  is  made  with  due  regard  to  the  total  number  of 
moldings  needed  and  to  the  rate  at  which  they  must  be  pro- 
vided. MB 


(it. 


f  /    IVTM  K 


SKITKMKKK  1946 


TO   PRODUCT   IN    PLASTICS 


Willson  hinge  strip  as  it  is  used  in  the  Amplex  Manufac- 
turing Company's  acrylic  box  for  holding  spools  of  nylon 


Right  hand  indicates  line  of  lamination  and  is  touching 
the  vinyl  strip  on  which  the  two  sheets  cf  acrylic  hinge 

"Built-in" 
Hinges 


THE  development  of  a  suitable  hinge  for  transparent 
plastics  boxes  and  other  parts  has  long  plagued  plastics 
designers.  The  Willson  Plastics  Division  of  the  Willson 
Magazine  Camera  Company,  Philadelphia,  is  now  offering 
an  ingenious  answer  in  the  form  of  a  Plexiglas-Vinylite 
laminate,  with  the  Plexiglas  cut  away  along  the  line  of  the 
hinge. 

Developed  by  T.  Carroll  Willson,  Jr.,  in  cooperation  with 
the  Design  and  Development  Staff  of  the  Rohm  &  Haas 
Company,  the  hinges  are  available  in  sheet  sizes  up  to  20" 
by  25"  in  a  variety  of  thicknesses.  Because  of  the  excel- 
lent fatigue  characteristics  of  vinyl  plastics,  the  flexing  life 
of  the  hinge  is  long.  The  transparency  of  the  material 
makes  the  hinge  an  inconspicuous  functional  design  element, 
eliminating  the  need  for  unsightly  metal  hardware.  Patents 
are  pending. 

The  hinge  stock  has  already  found  one  excellent  applica- 
tion. The  Amplex  Manufacturing  Company,  Philadelphia, 
is  utilizing  the  hinge  on  a  fabricated  box  of  Plexiglas 
adapted  for  the  hosiery  industry. 

The  box  contains  spools  of  nylon,  the  thread  being  fed 


»<••'*/*'  -"- 


}      the   Plastic 
Perfectionist 

STARTS  FROM  SCRATCH 
and  DELIVERS  THE  GOODS! 

"Just  give  me  your  blueprints,  no  matter 
how  complicated,"  says  Felsy,  "and  I'll 
have  your  plastic  parts  or  products  hop- 
ping out  of  here  like  popcorn  over  a 
hot  fire." 

Felsy 's  right:  All  we  need  is  the  kickoff 
to  get  going  with  your  idea,  and  we  will 
run  it  back  for  a  touchdown.  .  .  .  We  have 
the  skilled  personnel  and  equipment.  .  .  . 
We  have  the  WIDE  EXPERIENCE  re- 
quired to  size  up  unusual  plans  and  turn 
them  into  practical  plastic  realities.  If  it 
can  be  done  at  all— BY  INJECTION 
MOLDING,  LAMINATING,  OR  FABRI- 
CATING, we  can  do  it. 

Write  for  booklet  3-A  on  your  letterhead 


FELSENTHAL 
PLASTICS 

G.   FELSENTHAL   &   SONS 

4174  W.  GRAND  AVE.     CHICAGO  51,  ILL. 
BRANCH   OFFICES:   NEW   YORK   •    DETROIT 


SEPTEMBER  1946 


PLASTt CS 


67 


through  the  -^-veral  orifices  in  the  bottom.  The  box  is  mois- 
ture-proof and  dustproof  and,  of  course,  transparent. 

The  hinge  stock  makes  for  quick  opening  of  the  lid  when 
new  spools  are  inserted,  and  when  closed,  the  hinge  stock 
helps  to  maintain  the  security  of  the  lid  with  the  patented 
clips  employed  on  the  box. 

The  thickness  of  the  1'inylitt  in  this  hinge  is  .020";  of 
the  Pleriglas,  %".  I'inylitc  in  .012"  gauge  is  also  available. 

In  the  Amplex  box  the  hinge  is  secured  by  an  adhesive, 
but  it  would  be  possible  to  have  containers  in  which  the 
top  and  one  side  would  be  made  of  the  hinge  stock. 


END 


Silk-Screened  Acrylics 

(Continued  from  page  37) 


the  printed  piece  is  formed  to  contour,  the  design  which  has 
been  applied  is  subjected  to  the  forming  temperature  of  the 
pla-tK-,.  from  220°  F  to  350°  F.  The  composition  of  the 
paint  is  given  only  in  general  terms  as  "chiefly  solvents  and 
pigments,"  although  it  is  obvious  that  these  alone  will  not 
account  for  its  formability. 

The  Schulsinger  firm  has  applied  the  paint  in  a  number 
of  colors,  both  opaque  and  translucent,  and  in  multi-colored 
patterns,  including  color  overlaps  in  various  silk-screen 
operations. 

A  series  of  "on-the-spot"  checkings  made  in  connection 
with  this  discussion  served  to  exemplify  the  chief  results 
of  the  process.  A  rough  scratch  test  on  the  design  showed 
that  there  was  no  appreciable  difference  in  toughness  be- 
tween the  applied  paint  and  the  plastics.  Resistance  to 
abrasion  was  higher  in  the  paint  than  in  the  acrylic. 

A  blow-torch,  developing  a  temperature  of  about  1200°  F,  \ 
was  directed  on  a  printed  sample  until  bubbles  formed  in 
the  material  around  and  under  die  design,  but  there  was  no 
visible  effect  on  the  paint.  Under  blow-torch  temperature 
as  well  as  after  cooling  to  forming  temperature  (300°  F), 
*/i"  and  %"  pieces  were  twisted  and  flexed  in  spirals  and 
in  180°  bends.  The  design  under  these  conditions,  exam- 
ined under  12  magnifications,  showed  no  signs  of  cracking, 
flaking  or  pitting. 

One  of  the  most  revealing  tests  of  the  process  was  ob- 
served in  a  square-topped  drawn  piece.   This  piece,  like  the 
other  items  shown,  was  fabricated  by  Vargish  &  Co.,  New    I 
York,  was  drawn  from  Vi«"  silk-screened  methacrylate  sheet    \ 
to  a  depth  of  well  over  1".    The  stretch  along  the  sides  of 
the  draw  was,  therefore,  considerable,  but  the  silk-screened 
design  showed  no  flaws  and  no  diminution  of  adhesion. 

Sydney  Schulsinger,  head  of  the  silk-screen  firm,  empha- 
sized the  fact  that  he  utilized  the  new  paint  in  conventional 
silk-screen  procedure,  so  that  the  gain  in  desirable  qualities    ! 
in  the  new  process  is  not  offset  by  lost  production.         END 


Twisting    and   bending   ol    material   under   blow-larch 
heat  produced  no  appreciable  deterioration  ol  design 


PLASTICS 


SKITKMHKR  1916 


Compression  Mold  Design 


COMPRESSION  molds  are  of  several  classifications 
and  types  based  on  methods  of  ejection,  equipment 
used,  cavity  construction,  number  of  cavities,  etc.  In  order 
to  discuss  the  various  classifications,  the  methods  used  in 
compression  molding  should  be  considered  briefly. 

Reduced  to  its  simplest  form,  compression  molding  con- 
sists of  placing  some  powdered  material  into  a  cavity  in  the 
lower  half  of  a  heated  die,  and  causing  this  material  to  flow 
and  take  the  shape  of  the  die  by  forcing  the  punch  or  top 
half  into  the  cavity  by  means  of  a  hydraulic  press  (Fig.  1). 
After  the  heat  and  pressure  have  cured  the  material,  the 
mold  is  opened  and  the  piece  is  removed. 

The  process  has  been  used  for  many  years.  At  present, 
its  principal  use  is  on  the  thermosetting  compounds — the 
phenolics,  ureas,  and  the  melamines. 

Compression  molds  are  classified  in  various  ways.  To 
completely  describe  them  we  must  give  the  number  of  cav- 
ities, method  of  operation,  type  of  cavity  construction,  and 
special  features,  if  any. 

The  number  of  cavities  in  the  mold  is  the  first  thing  the 
mold  designer  must  know  before  he  begins  his  consideration 
of  the  design.  Two  main  considerations  determine  this 
number.  First  is  a  matter  of  economics.  The  mold  cost 
goes  up  with  an  increase  in  the  number  of  cavities,  but  the 
cost  of  the  moldings  goes  down.  Therefore,  the  amount  of 
production  anticipated  on  the  part  in  question  will  determine 
the  most  economical  size  of  mold.  The  method  of  arriving 
at  this  figure  was  discussed  at  length  in  the  recent  series  on 
injection  mold  design  (see  plastics.  May,  1946)  and  will 
not  be  repeated  here  as  it  is  substantially  the  same  for  a 
compression  mold. 

The  second  consideration  in  determining  the  number  of 
cavities  is  press  capacity.  Often  anticipated  production  is 
so  large  that  the  mold  should  be  made  as  large  as  possible. 
Here  the  designer  must  know  the  capacity  of  the  molding 
equipment  available  and  determine  the  number  of  cavities 
from  this  knowledge. 

This  computation  is  made  differently  than  on  injection 
work.  Two  factors  limit  the  cavities  for  a  given  press.  One 
is  the  platen  area  of  the  press  (Fig.  2).  The  mold  must  be 
small  enough  to  fit  between  the  posts  of  the  press  and  clamp 
on  the  platen  without  interfering  with  the  knockout  mechan- 
ism. The  second  consideration  is  one  of  available  pressure 
to  mold  the  piece.  Compression  molding  of  the  standard 
thermosetting  materials  requires  pressure  ranging  from  2000 
to  8000  psi  of  projected  area,  depending  on  the  material 
used  and  the  shape  of  the  molding. 

The  mold  designer  should  know  which  type  of  material 
will  be  used,  and  refer  to  the  table  in  Fig.  3  or,  preferably, 
to  the  more  detailed  data  sheets  put  out  by  the  manufacturer 
of  the  material  in  order  to  determine  what  pressure  will  be 
required. 

Calculating  the  Pressure 

He  must  also  know  the  available  pressure  in  the  press  to 
be  used.  When  line  pressure  is  known,  this  can  be  calcu- 
lated as  follows : 

LPXRA 

TP  = 

2000 

Where  TP  =  Total  pressure  available  in  tons 
LP  =  Line  pressure  in  psi 
RA  =  Ram  area  in  sq.  in. 

Knowing  the  total  pressure  available,  the  psi  required  for 
the  material  to  be  used,  and  the  projected  areas  of  the  piece 


HEAT/A 
PLATS KJ 


MOLD  -PUUCH  HALP 


MOLDWQ  P&esS<JK£ 


/="/<?.  / 


Part  I.  Discussions  ot  cavities, 
pressures,  methods  of  operation, 
other  keys  to  efficient  molding 


u  sTonn   O.  /So 


CLAMP  HOLES 


PL  AM   V/EW   OF  PKfSS   PLATE*/ 


SEPTEMBER  1946 


I'LASTtCS 


69 


Fig.  3.  Compression  Molding  Pressures 

R«comm«nded  Pretiurei 
Typ.  of  Mat.f ,ol  (psi) 


General  purpoje  phenolic 2,000-6,000 

Medium  impact  phenolic 3,500-6,500 

High  impact  phenolic 4,000-8,000 

Heot  re»i»lont  phenolic 3,500-6,000 

Urea  formaldehyde 3,000-9,000 

Alpha  cellulose  melamine 2,000-4,000 

Rag-filled  melamine 2,000-6,000 

Mineral-filled  melamine 1,000-5,000 

Deiign  of  part  determinei  whether  high  or  low  value  it  u»ed. 

to  be  molded,  the  number  of  cavities  which  the  press  can 
handle  is  calculated  by  the  following  formula : 
TPX2000 

N 

CAXMP 
\\  here  N  =  Number  of  cavities 

CA  =  Projected  area  of  one  cavity  in  sq.  in. 
M  1'  -=  Molding  pressure  required  in  psi 

In  the  projected  area  the  land  area  around  the  cavity 
must  be  included.  This  land  area  will  be  discussed  in  de- 
tail later  when  the  various  types  of  cavity  construction  arc- 
covered. 

By  method  of  classification  according  to  handling  we 
mean  the  way  the  mold  is  loaded  and  stripped.  There  are 
three  methods  of  operation:  hand,  semi-automatic  (S.  A.), 
and  automatic. 

The  hand  mold  is  one  which  is  loaded  on  the  bench  and 
then  placed  in  the  hydraulic  press  (Fig.  4a),  which  closes 
the  mold.  When  the  molding  has  been  allowed  to  cure,  the 
pressure  on  the  ram  is  released  and  the  press  opens  by  the 
weight  of  the  ram,  lower  platen,  and  mold.  The  mold  is  then 
removed  from  the  press  and  knocked  open  on  the  bench  or 
in  an  arbor  or  stripper  press  with  the  help  of  auxiliary 
equipment  known  as  box  and  pin  strippers  (Fig.  4b). 

Obviously,  this  type  of  mold  is  limited  in  size  of  molding 
and  number  of  cavities  to  the  weight  that  a  man  can  lift 
from  bench  to  press.  Therefore,  hand  molds  are  for  the 
most  part  single  cavity  or  a  few  cavities  of  small  objects. 
There  is  no  provision  in  a  hand  mold  for  the  heating.  They 
are  always  run  in  hot  platen  presses,  and  the  heat  necessary 
to  cure  the  molding  is  conducted  from  the  hot  platens  to  the 
mold.  Although  a  hand  mold  is  less  expensive  to  make  than 
any  other  type,  it  is  costly  to  run  because  it  requires  longer 
cure — resulting  from  the  cooling  of  the  mold  while  it  is  on 
the  bench — and  more  labor  time  is  required  to  attend  it  than 
other  types.  Therefore,  its  use  is  generally  limited  to  short 
run  items. 

It  is  well  suited  to  complicated  molds  having  many  in- 
serts, split  cavities,  side  cores,  or  loose  parts  to  handle,  as 
the  operator  can  do  this  type  of  work  more  satisfactorily 
out  on  the  bench  where  he  can  see  what  he  is  doing. 

In  order  to  overcome  the  limitations  of  the  hand  mold, 
the  semi-automatic  molding  press  was  developed.  This  is 
similar  to  the  hand  press  except  that  it  has  auxiliary  cylin- 
ders which  are  used  to  force  the  two  halves  of  the  press 
apart  by  hydraulic  pressure  when  the  ram  is  released.  This 
added  force  tending  to  open  the  press  makes  it  possible  to 
fasten  the  two  halves  of  the  mold  to  the  press  platens  and 
open  and  strip  the  mold  by  the  action  of  the  press  without 
removing  it  to  the  bench.  A  stripper  mechanism  is  incor- 
porated in  the  mold  to  fit  the  stripper  bars  on  the  press.  Fig. 
5a  and  Fig.  5b  show  a  semi-automatic  press  with  the  mold 
mounted  in  place. 

With  this  type  of  mold  the  operator  merely  removes  the 
pieces  after  the  press  has  stripped  them  from  the  mold 
cavity,  cleans  the  flash  from  the  mold,  loads  the  material 
for  the  next  round,  and  operates  the  valve.  By  not  having 


KVOCfOUT 
Ptu 


F/f.  4 -A 

HAW  HOLD  /A/  CLOSE? 
POS/T/OM 


HYP/tAt/ltc  eve 

'  eoKces 


opeu 


H4A/P 

TO  ope*/  /AJ 


P/At  STRIPPEB 

1**"*"  P/VS  Go  THO.U 

HOL£S   /M  TOP 
f*LAT£    OF  MOLD 

A  A/0  paesa  OAJ 

CAV/TY  HALf 


Box 


TOP  HALF  KESTS 
OA/  BOX-    CAVITY 
HALF  FTS  /A/  BOX 


/A/  POS/T/OAJ  KCADY 


ICHOCKOIIT  SAX 


.   SA 

fatSS  WITH 
HOLD  /N  ClOSCD 


70 


i»l..\STH°9i 


SKPTKMHKK  1916 


to  handle  the  mold,  he  saves  time  and  can  run  heavy  molds. 
These  semi-automatic  molds  get  their  heat  from  steam  chan- 
nels drilled  into  the  mold  itself,  and  therefore  more  uniform 
heating  can  be  obtained  than  with  a  hand  mold.  Fig.  6  shows 
a  typical  design  for  a  semi-automatic  mold. 

Completely  automatic  compression  molds  are  of  special- 
ized design  to  run  on  completely  automatic  molding  ma- 
chines. There  are  several  types  of  these  machines,  and  the 
problems  of  designing  molds  for  them  should  be  taken  up 
with  the  manufacturer  of  the  press  to  be  used.  His  advice 
should  always  be  sought  and  closely  followed. 

After  the  designer  has  decided  whether  the  mold  will  be 
hand,  semi-automatic,  or  fully  automatic,  he  must  choose  the 
type  of  cavity  construction  to  use.  The  several  types  to 
choose  from  are:  (1)  fully  positive;  (2)  flash;  (3)  landed 
positive;  (4)  semi-positive,  with  and  without  positive  por- 
tion; and  (5)  sub-cavity. 

The  fully  positive  mold  is  shown  in  Fig.  7.  It  will  be 
noted  that  there  is  nothing  to  keep  the  mold  from  closing 
except  the  material  trapped  in  the  cavity  by  the  punch  as  the 
mold  closes.  In  this  construction  all  the  pressure  exerted  by 
the  press  is  applied  to  the  material.  Thus,  moldings  are 
dense  and  of  good  quality.  Accurate  weighing  of  the  charge 
is  essential,  since,  assuming  uniform  pressure,  the  load  is 
the  only  thing  which  determines  the  thickness  of  the  mold- 
ing. Theoretically,  since  there  is  no  clearance  between  the 
cavity  and  punch,  the  material  will  be  completely  trapped 
by  the  punch;  but  in  practice  .002  to  .005  clearance  is 
needed  to  permit  the  escape  of  gases.  The  thin  sheet  of 
material  which  starts  to  escape  through  this  clearance  quick- 
ly sets  up  and  forms  flash,  thus  sealing  further  escape.  This 
type  of  mold  is  used  for  molding  laboratory  test  pieces,  but 
is  seldom  found  in  commercial  operation  as  it  is  not  adapt- 
able to  all  part  designs,  requires  extreme  care  in  loading, 
and  is  subject  to  wear  and  scoring  at  the  telescoping  portion 
which  would  soon  result  in  costly  maintenance  or  failure. 


The  flash  mold  (Fig.  8)  is  a  popular  type.  It  has  no  way 
of  trapping  the  materials  in  the  cavity  and  depends  on  back 
pressure  built  up  around  the  flash  ridge  or  land  during  the 
final  few  thousandths  of  an  inch  of  closing. 

It  is  the  cheapest  type  to  make,  and  usually  the  fastest  to 
operate  because  of  ease  of  cleaning.  There  are  no  telescop- 
ing parts  to  wear  or  score  so  maintenance  is  at  a  minimum. 
However,  it  cannot  be  used  on  all  applications  as  no  pres- 
sure is  built  up  on  the  molding  material  until  the  press  is 
almost  closed.  Therefore,  many  moldings  will  not  fill  out 
satisfactorily,  or  if  they  do  fill  out  they  are  inferior  in  phys- 
ical properties  because  of  low  density.  It  is  not  recom- 
mended for  the  higher  impact  materials  that  do  not  flow 
readily.  There  is  considerable  waste  of  molding  powder  in 
this  type  of  mold  as  a  large  portion  spills  over  the  edge  of 
the  cavity  before  the  flash  sets  up  to  prevent  this.  There- 
fore cavities  have  to  be  overloaded  to  assure  full  castings. 
If  long  production  runs  are  expected,  the  saving  in  mold 
making  cost  for  a  flash  mold  may  be  offset  by  the  additional 
cost  of  material  required  to  make  the  pieces. 

Bulk  Factor  Influences  Design 

All  molding  materials  have  a  bulk  factor.  This  is  the 
ratio  of  the  volume  of  the  loose  molding  powder  to  the 
volume  of  the  molded  piece.  It  varies  2%  to  1  to  15  to  1 
depending  on  the  filler  used.  This  factor  must  be  taken  into 
consideration  in  designing  the  mold,  as  there  must  be  room 
in  the  cavity  to  receive  the  unmplded  material  at  its  higher 
bulk.  Obviously  there  is  no  way  to  allow  for  this  in  a 
flash  mold  unless  the  shape  of  the  finished  piece  is  such  that 
the  punch  half  of  the  die  is  large  enough  to  replace  the 
necessary  volume  of  material  as  it  closes.  The  use  of  the 
flash  mold  is  therefore  limited  by  piece  design  and  bulk 
factor. 

Pills  or  preforms  can  often  be  used  to  load  the  cavity  in- 
stead of  the  loose  powder.  In  this  case  the  bulk  factor  can 


.    S  ff 


5EM/  - 


CLAMP  I-CDGf 


SeMt-AUTOMAT/C   MOLP 


CAWTY 


FULL 


SEPTEMBER  1946 


PLASTICS 


71 


9  A 

LAMPfD    POStTlt/S 


Of  STEEL     OH 
PUASCH    Of 


.    9B 

5HOI4//MG    WEAK  CONDITION  OAJ 
Pt/K/CH   WHICH UMITS    USE    Of 
POSlTl(/£  MOLD 


/OA 

MOLD  H>ITH   HOftJOIurAL 


72 


f  LAST  tCti 


be  reduced  as  low  as  1^2  to  1.  This  makes  the  use  of  the 
flash  mold  possible  cm  many  applications  where  it  wouk 
otherwise  IK-  ini|H>ssible.  Xot  all  of  the  molding  materials 
are  suitable  for  economical  preforming,  and  this  should  b« 
checked  into  with  the  material  supplier  before  the  mold  is 
designed  for  preform-. 

Flash  thickness  varies   with   speed  of  closing,  load, 
flow  of  material,  and  therefore  the  thickness  of  the  piece  \\  il 
also  vary.    ( 'lose  tolerance  cannot  be  held  across  the  pa 
line.   Flash  nmlils  also  often  give  trouble  on  deep  draw  itemi 
such  as  radio  cabinets,  and  care  should  be  taken  in  thein 
-election   lor   this  type  of  work.      If  there   i-   a   possibility1 
that   urea   may  he   used   in  the  mold,  and   there   u-ua' 
a  flash  ty|K-  should  not  be  made.     If  the  mold  i-  to  l>e  u-ed 
on  wood  Hour  phenolic  and  if  the  side  wall-  of  the 
are  thinner  at  the  top  than  the  bottom,  a  flash  mold  may  be 
used,     'llii-  wall  design  give-  wedging  action  to  help  pacl 
the  material. 

There  are  several  compromise  construction-  t>et\\een  the 
true  positive  and  the  flash  types.  One  of  these  is  the  landed 
positive  mold  (  Fig.  ('a).  This  is  not  really  a  positive  mold 
in  the  -en-e  that  the  pressure  i-  on  the  material  during  th< 
whole  cure  time.  It  comes  to  a  stop  on  a  metal  to  met. 
tact,  but  the  material  is  trapped  when  the  plunger  enter-  tht 
cavity  and  enough  pressure  is  exerted  to  produce  good  mold- 
ings. It  has  a  definite  stop  to  determine  the  thickness  of 
molding  and  therefore  does  not  require  such  accurate 
urcment  of  the  load  a-  a  truly  positive  mold.  Th. 
will  IK-  less  dense  than  those  from  the  true  positive 
superior  to  those  of  the  flash  mold  unless  the  plunger  i- 
loose  in  the  cavity.  This  mold  gives  opportunity  for  ampk 
loading  space  for  the  bulkier  materials,  and  the  flash  thick- 
ness is  controlled  by  the  clearance  K-tween  punch  and  ca\  ity 
Therefore,  trimming  can  be  kept  to  a  minimum  by  keeping  I 
small  clearance. 

This  type  can  be  used  on  all  materials  if  tight,  and  I 
especially  suited  to  the  impact  phenol ics  because  of  the  con- 
trollable flash  thickness.  It  has  the  disadvantage-  of  In-ing 
subject  to  wear  and  scoring  because  of  the  telescoping  parts, 
It  cannot  be  used  on  all  part  designs  as  on  some  it  would 
cause  a  weak  section  on  the  punch,  which  would  crarl.  in 
service  under  the  high  molding  pressures  involved.  Fig.  91 
-how-  -nch  a  punch.  On  items  of  this  kind  some 
type  of  mold  must  be  used. 

Another  compromise  design  is  the  senii-jxisitive  mold 
This  design  is  a  very  popular  one  and  is  in  general  u-e.  l.ikc 
the  landed  positive  it  is  really  not  a  ]x>sitive  at  all  but  adopt! 
many  of  the  feature-  of  the  jHisitive  to  make  it  a 
running -type  and  thus  be  the  only  logical  means  to  mold 
many  pieces. 

It  conies  in  two  types,  with  horizontal  flash   (Fig.  10a 
and  with  vertical  flash   (Fig.  lOb). 

With  the  hon/oiital  fla-h  it  is  probably  the  most  comma 
mold  in  u-e.    Adaptable  to  more  designs  and  materials  thai 
any  other  ty|H\  it  give-  the  necessary  material  well  to  hanc 
the  bulkier  ooni|>ound-.  and  produces  good  dense  moldinj 
It  is  nit  ire  expen-ive  to  make  than  the  flash  type,  but  is  t 
cheapest  of  the  contained  types  to  maintain  a-  wear  an 
-coring  of  the  telescoping  parts  do  not  cause  serious  da  magi 
The  material  is  trapped  on  the  flash  ledge  or  land  and  th 
doe-  not  depend  entirely  on  a  tight  fit  between  punch  and 
cavity  for  the  molding  pressure. 

I'.i-i-au-e  of  a  hori/tmtal  cutoff,  it  is  difficult  to  maintai 
a  thin  flash  and  close  tolerance  across  the  parting  line, 
Therefore,   trimming  may  be  difficult  especially   in   piece 
molded  from  impact  materials. 

This  last  objection  can  be  overcome  by  leaving  a  sma 
telescoping  portion  on  the  punch,  which  gives  a  vertio 
(Continued  on  page  92) 

SEPTEMBKR   1M16 


Base,  contact  arm  and  tripshaft  of  new  circuit  breaker 

Molded  Circuit 
Breaker  Parts 


THREE  plastics  parts  in  the  new  General  Electric  cir- 
cuit breakers  bring  out  some  new  wrinkles  in  the  manu- 
facture of  products  by  molding. 

The  three  parts  of  the  breaker  assembly — namely,-  the 
main  base,  the  contact  arm,  and  the  tripshaft — are  molded 
from  black  phenol  formaldehyde  by  the  transfer  molding 
process.  New  and  unique  design  features  have  been  de- 
veloped to  eliminate  the  use  of  inserts  and  bring  about  a 
consequent  reduction  in  cost. 

Although  each  part  contains  many  intricate  designs,  the 
molding  was  done,  according  to  General  Electric  plastics 
engineers,  without  loose  wedges  or  cross-pins  in  the  mold. 
This,  they  say,  is  of  special  interest  because  of  the  inclusion 
of  numerous  cross-holes  and  small  projections. 

The  cross-holes  required  no  drilling  or  machining.  They 
are  the  result  of  two  slots  originating  from  opposite  direc- 
ticm>  with  the  plunger  and  cavity  members  passing  to  form 
the  hole  perpendicular  to  the  direction  of  molding. 

Projections 

Still  another  noteworthy  feature  is  the  incorporation  of 
six  internal  projections  Mu"  thick  in  each  of  two  square 
holes  approximately  s/2"  on  a  side.  These  are  integral  parts 
of  the  molding  and  allow  the  locking  of  metal  pieces  in 
the  tripshaft.  Other  projections  illustrating  difficult  mold- 
ing procedure  are  external  bosses  Yz"  thick  and  an  inch 

long. 

In  addition,  the  molded  base  has  side  openings  and  bear- 

g  supports. 


Be  sure  to  read  the  following  features  in  next  month's 

plastics 

(1)  a   description   of  how  the   use   of   polyethylene 
coatings  on  aircraft  external  radio  parts  prevents 
precipitation  static. 

(2)  a  second  article  on  the  plastics  operations  of  the 
Ford   Motor  Co.,  describing  unusual  setups  for 
machining  and  finishing  molded  parts. 


FILFLOC 

uniformity. 


Pure  cotton  flock 


1*101)1  Til 

rABKIML 


Uniformly   pre- 


oted  cotton  fab- 
ric  for   extra  strength. 


—  but  I  N  NUMERABLE 
MODIFICATIONS  to  fit  your 
every  need  EXACTLY! 

Small  differences  in  cut  and  preparation  of  fillers 
actually  produce  substantial  differences  in  perform- 
ance qualities  of  the  finished  plastic  product.  We 
"Research-fit"  our  fillers  to  YOUR  needs.  Every  item 
requiring  a  different  compound  gets  the  filler  element 
that  fits  the  product  exactly.  As  a  result,  you  receive 
the  MAXIMUM  advantages  from  the  use  of  cotton 
fillers — the  type  of  fillers  which  have  made  possible 
new  uses  for  plastics.  Free  samples  and  research 
counsel  are  available  to  you. 

Working  Sample  Free 


of  R.I. 

INC. 


RAYON  PROCESSING  CO. 

45    TREMONT    ST.,  CENTRAL    FAllS,    RHODE     ISLAND 

a*td 
QillenA  (o* 


SEPTEMBER  1946 


i'l.ASTtCS 


73 


WHAT'S 


PLASTICS 


Jacket  Oil  Heater 

The  Youngstown  Miller  Co. 
675  Main  St..  Belleville  9.  N.  ). 

A  new  line  of  jacket  oil  heaters  in  4  standard  sizes  ranging 
from  14  to  65  kw  has  been  developed  to  meet  the  increasing  de- 
mand for  an  efficient,  economical,  low  pressure  heat  transfer 
system  for  cylinder  jackets  and  dies  of  plastics  extruders,  calen- 
der rolls,  and  similar  jacketed  equipment. 

These  units  offer  the  following  advantage :  out-,  two,  three  or 
more  temp  simultaneously :  wide  temp  range ;  accurate  temp 
controls;  5  to  150  kw  of  heat  or  more  if  required;  temp  variable 
through  manual  selection ;  stationary  or  portable  models. 

Requiring  only  a  power  line  connection  and  a  small  amount 
of  external  piping,  these  compact,  self-contained  units  can  be 
installed  quickly  and  inexpensively.  Finned  tube  heaters, 
through  which  heat  transfer  oil  is  pumped,  supply  the  heat. 
Special  units  to  supply  any  volume  of  heat  at  temp  up  to  550°  F 
will  be  furnished (572) 


High  Vacuum  Coating  Unit 

National  Research  Corporation 
Park  Square  Bldg.,  Boston,  Mass. 

Developed  to  permit  low-cost  mass  production  of  plastics  or 
glass  surfaces  coated  with  metallic  or  low-reflection  film-,,  tin 
industrial  high  vacuum  coating  unit  .\'o.  3103  is  of  interest  to  the 
plastics  industry  for  decorative  coatings,  and  to  the  optical  -in- 
dustry for  optical  coatings. 

A  48"  by  48"  stainless  steel  cylindrical  tank,  mounted  horizon- 


tally, is  the  vacuum  chamber.  This  tank  is  said  to  handle  small 
pieces  in  large  quantities,  and  to  make  possible  the  coating  of 
large  pieces. 

Two  10"  diffusion  pumps,  with  a  combined  capacity  of  6000 
rim,  are  manifolded  by  a  14"  high  vacuum  valve  and  backed  by  a 
100  cfm  mechanical  pump  to  reduce  the  pressure  in  a  clear  dry 
tank  to  the  desired  point  in  about  10  min.  This  unit  is  expecn 
to  run  three  complete  coating  cycles  per  hour  in  production,  with 
charges  of  plastics  pieces (573) 


New  Circle  Cutter 

Water  ston's 

16  Lamed  St..  Detroit  26.  Mich. 

Cutting  hole-,  discs  ami  circles 
in  plastics,  wood,  and  other  ma- 
tt rial-  without  drilling  a  pilot 
hole  in  the  center  of  the  work, 
the  3-in-l  Circle  Cutler  pilots 
with  a  spring  tension 'cone  center. 
This  feature,  in  addition  to  hold- 
inn  the  work  down  on  the  table, 
IK-rmits  the  user  to  later  drill 
any  si/e  center  hole  he  may  w  i-^h 
for  nail,  dowel  or  screw.  If  a 
solid  disc  is  desired,  there  is  no 
hole  to  be  plugged.  This  tool  it 

designed  for  use  in  drill  press,  handsaw  or  jigsaw.   It  has  a  l/i* 

straight  shank  for  mounting  in  chuck  or  spindle  of  a  drill  press. 


(plctAticA 


Expressly  designed  for 
granulating  the  various 
types  of  plastic  materials 

Advanced  design  features  enable 
Cumberland  machines  to  perform  at 
maximum  efficiency  the  special  cut- 
ting required  by  plastics  materials. 
Machines  are  made  in  two  styles: 
smaller  machines.  No.  0,  No.  ¥2  and 
No.  l'/j  as  at  right  (No.  Vi  illus- 
trated). Style  oi  large  machines  as  at 
left  with  retractable 
knife  block  for  maxi- 
mum accessibility  (18" 
Machine  illustrated). 

Request  illustrated 
CATALOG  NO.  200 

CUMBERLAND  ENGINEERING  CO. 

Dept.  •—lei  214.  Providence.  R.  I. 


74 


PL  AST I CS 


SKPTKMBKR   1!U6 


and  mounted  thus  will   cut  the  diameter   of    1J4"  to  8"   to  a 
depth  of  1". 

With  an  adaptor,  it  can  be  mounted  on  any  standard  band  or 
scroll  saw,  and  cut  dia  up  to  14"  in  depths  according  to  the 
capacity  of  the  machine.  Perpendicular  sides  are  assured  over 
the  complete  range (574) 


Industrial  Heating  Plate 

Delt  Calesco  Company 
Far  Hills,  N.  J. 

Made  of  tempered  glass  having  a  pattern  of  special  alloy  fused 
on  one  side,  the  Calesco  Infra-Lectric  Plate  is  described  as  per- 
forming a  superior  job  in  meeting  the  most  exacting  demands  for 
heat  requirements. 

It  operates  without  flame  and  without  glow.  With  the  use  of 
a  Fenwal  Thcrmoswitch,  any  degree  of  heat  up  to  380°  F  can  be 
maintained,  with  slight  variation.  When  compared  with  other 
forms  of  infra-red  heat,  these  plates  have  been  found  to  be  both 
practical  and  low-cost  in  operation.  An  unusually  even  distri- 
bution of  heat  is  listed  as  one  of  its  chief  advantages.  Another 
i-  in  the  heat-treatment  of  various  plastics  materials,  where  it  is 
possible  in  many  instances  to  bring  the  materials  in  direct  con- 
tact with  the  plate  surface. 

Kach  plate  is  framed  with  aluminum,  thoroughly  insulated  and 
wired  for  immediate  use.  There  are  two  standard  sizes :  16"  by 
24"  operating  on  110  v  ;  and  16"  by  48"  operating  on  220  v. .  (575) 


For  Dielectric  Heating 

Raytheon  Mfg.  Co.,  Industrial  Electronics  Div. 
Waltham  54.  Mass. 

Said  to  offer  tne  most  modern  features  of  dielectric  heating, 
Raytheon's  Raytherm  has  numerous  applications  in  such  varied 
fields  as  plastics,  ceramics,  paper,  textiles,  leather,  wood,  and 
many  others. 

Used  in  the  plastics  industry  for  the  preheating  of  thermoset- 
ting  and  thermoplastic  materials  prior  to  molding ;  setting  and 


post  formation  of  laminates ;  and  seam  bonding  of  thermoplastic 
films ;  this  type  of  heating  enables  synthetic  resins  to  polymerize 
quickly  and  efficiently. 

Riiythcnn  D5G,  a  5  kw  general  purpose  unit,  is  5'  llyii"  high, 


In  rapidly  moving  times  such  as  these,  keeping  up 
with  every  latest  development  in  one's  field  is  a 
"must."  In  order  to  simplify  for  our  readers  the  task 
of  obtaining  detailed  information  regarding  the  new 
products,  processes  and  trade  literature  described 
herein,  plastics  has  keyed  each  item  in  this  section 
with  a  number,  and  has  provided  the  name  and  ad- 
dress of  the  manufacturer  «r  producer  of  each. 

Mention  of  the  key  number,  and  of  the  issue  of 
pfostfcs  in  which  the  news  item  appeared,  will  serve 
as  quick  identification  of  the  product  when  writing 
the  individual  manufacturer  or  producer  for  further 
detaHs. 


TO  YOUR  SPECIFICATIONS 

For  over  forty  years  we  have  been  leaders  in  the  design 
and  manufacture  of  component  parts  for  leading 
Refrigerator,  Stove,  Furniture,  Appliance  and  Cabinet 
industries.  We  specialize  in  custom  molding  by  the 
injection,  compression  or  transfer  method  in  any  ther- 
mosetting  or  thermoplastic  material.  A  complete  ser- 
vice from  one  source  to  serve  your  needs  —  at  no 
extra  cost. 


RESEARCH  — 

Highly  experienc- 
ed research  engi- 
neers to  deter- 
mine the  material  best  suited 
for  your  needs  as  to  strength, 
utility  and  beauty. 


ENGINEERING— 
Here  is  where  the 
correct  tools,  pre- 
cision dies  and 
molds  are  developed  to  pro- 
duce tne  best  job,  efficiently 
and  economically. 


MOLDING  —  A 
complete  depart- 
ment equipped 
with  the  latest 
and  most  modern  presses  and 
molding  equipment  —  for 
Injection,  Compression  or 
Transfer  molding. 


DESIGN  —  A  thor- 
ough study  is  made 
as  to  the  utility, 
shape  and  color  of 
the  plastic  part  that  will  best 
harmonize  with  the  style  and 
design  of  your  product. 


TOOL  AND  MOLD 
MAKING  —  This 
department,  manned 
by  expert  crafts- 
makes  the  necessary 

tools  and  molds  to  produce 

the  finished  product. 


men, 


INSPECTION 
AND  SHIPPING 

Each  individual 
piece  is  carefully 
inspected  for  uniformity,  col- 
or and  finish.  All  parts  arc 
carefully  wrapped  and  packed 
for  utmost  protection. 


If  you  are  planning  the  use  oj  plastic  farts  in  your 
products,  it  will  be  advantageous  for  you  to  investi- 
gate our  complete  service.  Write  or  phone  us  about 
your  needs. 


NATIONAL    LOCK 

COMPANY 

Plastics   Division 

ROCKFORD,    ILLINOIS 


SEPTEMBER  1946 


PLASTICS 


75 


WE   BUY 


Thermoplastic  Scrap  - 
Rejected  Molded  Pieces 
_  Obsolete  Molding 

Powders-and  pay 

highest  prices 


SELL 


to  fit  your 


-''  4"  wide.  3'  10^"  long.   It  is  constructed  of  heavy-gaged  sheet] 
metal  ribbed  for  strength  on  a  welded,  structural  shape  frame- 
work, and  is  complete  in  one  cabinet.    Claimed  by   its  manu- 
facturer to  provide  greater  flexibility  or  "set  up"  operation  when 
a  specific  production  piece  is  desired,  this  unit  is  complete  with 
meters,  cycle  timer,  interlocks,  safety  switch,  and  all  net . 
control  circuits  for  push-button  operation ;~- 


Multiple-Opening  Platen  Press 

R.  D.  Wood  Company 

Public  Ledger  Bldg..  Philadelphia  5.  Pa. 

1  >csigned  for  the  laminating 
and  |K>lisliing  of  plastics  sheets 
and  the  curing  of  rubber  prod- 
ucts.  tlii-  new  multiple-opening 
platen  press  can  be  operated  at 
pressures  up  to  1500  psi. 

Keyed  joints  and  bolts  lock 
the  side  slabs  to  the  top  platen 
and  cylinder  castings ;  while  steel 
tire  r<xls.  shrunk  into  position  at 
assembly,  assure  a  rigid  compact 
unit.  Platens  measure  30*  X  30" 
X2",  and  can  be  either  steam  or 
electrically  heated. 

Positive  guiding  of  the  platen 
over  the  full  stroke  of  the  press 
is  assured  by  the  use  of  machined 
guide  blocks  which  are  securely  bolted  to  the  moving  press  plate:) 
and  slide  on  machined  vertical  guides  attached  to  the  inner  face 
of  each  side  slab.  Intermediate  platens  are  guided  at  each  corner 
on  machined  steel  guide  strips  and  are  spaced,  by  stepped-type 
hangers,  with  4"  daylight  between  each  platen,  when  press  i-  in 
open  position.  When  required,  provision  is  made  for  spacing  the 
platens  with  2y2"  daylight.  Press  can  be  furnished  with  or  with- 
out  elevators (577) 

Light  Belt  Grinder  Attachment 

Porter-Coble  Machine  Co. 
Syracuse.  N.  Y. 

Combining  the  versatility  of  platen  grinding  with  the  economy 
and  speed  of  contact  grinding,  the  new  light,  narrow  belt  grinder 
attachment  \n.  \-2  is  claimed  by  its  manufacturer  to  IK-  ideal 
for  light  grinding  of  flats,  arcs,  angles,  weld  grinding,  etc.  A 
wide  variety  of  plastics  and  composition  materials,  as  well  as 
steel,  iron,  aluminum,  wood  and  glass  are  easily  groin 
surfaced. 

The  complete  unit  assembly  is  _'/"  by  2>/j",  with  a  (•"  l«»   , 
shaped  base  drilled   with   3   holes   for  convenient   mounting   to 
bench  or  work  table.    Using  an  endless  abrasive  belt,  the  attach- 
ment can  be  used  in  any  position  (angle  )  between  the  90°  . 


P^^B— 

Your  scrap  ior  you 
WE  SPECIALIZE  in  cus- 
tom grinding,  magnetiz- 
ing.  separating  an. 
reworking. 


CCUIUSE  ICCUTI    .    MlMtYlflt    •    HCIIYl  •UIUITUU 

A.BAMBERGER 

CORPORATION 
44     HIWIS     STRUT.     «»OOKIYN     11,     N.     V. 

fHONl  m»G»HN  7  .JM7  •  CABtl  CHEMMOD  MOOKtrN 


ceitinst  uni 


rimmu  IESINS.  lie 


Temperature  Control  Unit 

Claud  S.  Gordon  Company 

3000  S.  Wallace  St..  Chicago  16.  111. 

Providing  unusually  close 
temperature-  variation  control 
with  variation  as  low  as  1/5  of 
a  degree  !•".  and  power  "on-off" 
rules  a»  short  as  3  set',  the  new 
Xaclliiif  temp  control  d<x>  not 
use  any  rotating  mechanical 
parts. 

According  to  the  manufac- 
turer, this  unit  is  a  solution  for 
rosily  overshoot  and  undershoot 
temp  variations  prevalent  in  the 
plastics,  molding,  tempering, 
aluminum  heat  treating  ami 
other  heat  processing  fields.  It 
•.  pi-n^ivc  and  can  IK-  used 
on  all  types  oi  electric  furnaces. 
ovens,  injection  molding  ma- 
chine*, etc  .  employing  conventional  millivoltmcter  and  poter 
ometcr  t\pc  controlling  pyrometers,  or  gas-fired  equipment  c 
ploying  solenoid  lontrolled  or  motor  operated  valves. 

•ned  for  surface  mounting   insiallation.  it   is  housed  tr 
i.i^t  aluminum  case  X'  ,"  I.T  (.'  ,'    l>\    .<" 


7fi 


I'I..\STI1  S 


SK1TKMKKK   1S46 


Literature  Review 


Synthane  Products 

Synthcme  Corporation 
Oaks,  Pennsylvania 

New  catalog  lists  and  describes  this  company's  wide  variety  of 
products ;  shows  how  they  are  produced ;  lists  properties,  colors, 
finishes,  and  sizes  in  which  they  may  be  obtained (580) 


Metal-Clad,  Resin-Bonded  Plywood 

Haskelite  Manufacturing  Corporation 
Grand  Rapids,  Michigan 

Well-illustrated  20-page  booklet  titled  "Plymetl— a  Material 
of  Opportunities,"  discusses  methods  of  fabricating  and  finishing 
the  new  development  of  metal-clad,  resin-bonded  plywood. 
Included  is  a  stiffness  comparison  chart  on  Plymetl,  steel,  and 
aluminum.  Various  applications  for  the  new  Plymetl  are  also 
listed  (581) 


Bulletin  Describes  Presses 

Air-Hydraulics,  Inc. 

401  Broadway,  New  York  13,  N.  Y. 

Air-Hydraulic  Presses  widely  used  in  riveting,  forming,  light 
broaching,  crimping,  stripping,  heat  sealing  and  assembly  opera- 
tions, are  described  in  a  new  8-page  bulletin.  These  presses  have 
ram  pressure  controlled  up  to  5000  Ibs,  adjustable  stroke  of  Vie" 
to  5",  and  adjustable  ram  speed (582) 


Hyprez  Diamond  Compound 

Engis  Equipment  Company 

431  S.  Dearborn  St.,  Chicago  5,  111. 

Descriptive  folder  introduces  the  new  Hypres  Diamond  Com- 
pound which  is  used,  among  other  applications,  in  the  production 
of  plastics  molding  dies.  This  compound  is  said  to  permit  the 
finish  of  such  dies  to  a  uniform  fine  and  lustrous  finish  without 
any  visible  scratches  or  marks (583) 


Catalog  of  Switches 

Micro  Switch 
Freeport,  Illinois 

Catalog  No.  61,  an  excellent  handbook  for  design  and  pro- 
duction engineers,  fully  describes  and  illustrates  many  of  the 
varied  uses  for  the  company's  products.  The  many  types  of 
housings  for  Micro  Switch  snap-action,  along  with  varied  types 
of  actuators  that  make  possible  the  use  of  these  products  to  make 
machines  automatic,  for  machine  limit  and  control,  to  aid  in  po- 
sitioning materials,  to  control  electrical  current  and/or  temp,  are 
listed  .  (584) 


Electronic  Micrometers 

Carson  Micrometer  Corp.,  Dept.  16 
28  Edison  Place,  Newark  2,  N.  J. 

Four  ro-designed  models  of  electronic  micrometers  for  precise 
thickness  measurement  in  the  shop  or  laboratory  are  described 
and  illustrated  in  a  4-page  file-size  folder  issued  by  the  manu- 
facturer:  Model  L  for  pressureless  measurement  of  conducting 
parts;  Model  M  for  measuring  thickness  of  any  material  (hard 
or  soft,  conducting  or  non-conducting);  Muriels  II'  and  .S  for 
pressureless  measurement  against  conducting  surfaces. ...  (585) 

Cooling  Units 

Tenney  Engineering,  Inc. 

26  Avenue  B,  Newark  5,  N.  J. 

I  k'signatjd  as  Catalan  Cl)4f>,  an  attractive  20-page  booklet  in 
culm-,  on  cooling  units,  has  just  been  announced  by  the  manu- 
facturer. Among  the  products  described  are  the  Tenney  unit 
cooler.-.,  Kwik-Freezc  lee  Milkers,  coil  and  pan  combinations, 
wall  mounted  panel  units,  bare  tube  coils,  etc.  Sizes  and  prices, 
coil  selection  tables,  formulae  for  determining  coil  sizes  and 
other  valuable  engineering  data,  are  included (586) 


New  available  in  many 

beautiful  colors  and 

for  every  purpose. 


Do  not  accept  substitutes. 
There  is  only  one  plastic 
—CELLO-PLASTIC. 


Brings  New  Colorful  Beauty  and  Durable  Protection  to 
FLOORS*  WOODWORK*  WALLS  *  EXTERIORS 


Plastic  is  now  prepared  in 
liquid  paint  form  for  use  in 
home,  office,  store,  and  factory . 
This  has  come  about  through 
the  formulation  of  synthetic 
resins  with  specially  processed 


oils  combined  with  the  finest 
paint  pigments.  ACello- Plastic 
product  is  available  for  almost 
any  type  of  finish  or  surface. 
Does  not  chip  or  crack! 


BRILLIANT  *  SMOOTH  *  TOUGH  *  DURABLE 

ff\O  Fl  OODC  Cello-Plastic  f transparent,/  ii a  non-skid  plastic 
r\*K  rUV/V/l*a  jnish  for  all  types  of  floors.  This  touring  new 
treatment  gives  floors  a  "cellophane-like"  Plastic  finish.  Eliminates  pores  that 
absorb  din.  thus  making  floors  easy  to  clean.  Ideal  for  all  surfaces  including 
wood,  concrete,  linoleum,  asphalt,  tile  rubber,  composition,  etc.  Eliminates 
waxing  and  polishing.  Unexcelled  for  marine  use. 

EY  T  F  P  I  O  R  This  modern  finish  is  a  severely  tested  product 
**  •  K  •*  •  **  •*  that  surpasses  old  fashioned  type  house  paints. 
Pigmented  with  Titanium  Dioxide,  the  whitest  and  best  covering  pigment, 
combined  with  kettle  processed  linseed  oils  and  plastic  resins,  it  makes  a  rich, 
colorful,  lasting  coating.  Makes  homes  and  buildings  outstanding.  For  use  on 
wood,  stucco,  Brick  or  shingle. 

IKITFPIOR     Brings  new  glamour  into  homes — protect  floors, 
1  ™  •*  *  **  •*    woodwork,  furniture,  etc.,  with  its   long-lasBng, 
"cellophane-like"  Plastic  finish.  Easy  to  apply — flows  smoothly — leaves  no 
brush  marks — self  leveling. 

Inquiries  from  Exporters  and  Dealers  Solicited 

Product  liability  underwritten  by  one  of  America's 
largest  insurance  companies. 


CELLO-PLASTIC  CHEMICAL  CO. 

417-419  BLVD.  OF  ALLIES,  PITTSBURGH  19,   PA. 


SEPTEMBER  1946 


PLASTICS 


77 


Seamless  Display  Forms 

Make  Their  Debut 


Fully  rounded  shoulder  and  neck  portion*  distinguish  torso 
model  which  is  made  in  black  and  in  transparent  "Plexiglas." 
Below,  brassiere  and  blouse  display  models,  made  before  de- 
velopment of  present  "rounding-out"  technique,  lacked  depth 


DISPLAY  forms  for  showing  merchandise  such  as 
blouses,  lingerie,  and  other  articles  of  feminine  ap- 
parel are  extremely  effective,  as  well  as  utilitarian,  when" 
made  of  plastics.  For  their  several  purposes,  these  models, 
or  forms,  are  made  as  reproductions  of  the  upper  or  the 
lower  portion  of  the  torso,  the  leg,  arm,  etc. 

The  ultimate  production  of  an  entirely  seamless  plastics 
model  of  the  human  figure,  from  neck  to  a  point  below  the 
knee  (although  not  including  arms)  is,  however,  the  aim  of 
Scheuer  Creations,  Inc.,  New  York  City,  maker  of  display 
items.  This  company  has  already  perfected  a  technique 
for  forming  a  display  torso  of  considerable  depth.  MI  that 
when  viewed  from  the  front  it  gives  the  appearance  of  a 
fully  sculptured  torso  form.  According  to  riemens  Scheuer, 
head  of  the  firm,  the  company  has,  to  date,  sold  more  than 
3000  of  these  models,  which  reproduce,  in  gracefully  flow- 
ing lines,  the  contours  of  the  female  body  from  thighs  to 
deep-drawn  rounded  neck,  and  include  upper  back  and 
shoulders.  By  employing  the  same  procedure  used  to  make 
this  torso  form,  Scheuer  feels  certain  that  it  will  be  pos- 
sible to  fabricate  a  figure  Vntirely  "in  the  round." 

The  process  now  used  by  the  company  is  a  culmination  of 
years  of  research  during  which  all  of  the  major  techniques 
of  sheet  forming  and  drawing  were  used  in  experiment. 
three  of  them  being  utilized  in  this  latest  development  of  the 
torso  model. 

The  models  are  produced  in  clear,  transparent  I'lcxiglas 
and  in  lustrous,  black  I'lcxii/las.  The  latter  is  said  to  have 
proved  more  popular  with  display  people,  as  it  afford-  a 
sharply  contrasting  background  for  the  white  or  pa-tel- 
toned  lingerie  for  which  it  is  used. 

Some  seven  years  ago,  the  Scheuer  firm,  which  had  been 
producing  display  items  fashioned  of  acrylic  rod,  began 
forming  acrylic  sheet  stock  into  bust  models  for  brassiere 
displays.  The  original  small  model  reproduced  only  the  bust 
section,  using  the  classic  method  of  stretching  the  heated 
plastics  material  over  a  form,  and,  when  fully  drawn,  clamp- 
ing it  to  the  form  to  cool  into  its  permanent  shape. 

After  a  certain  amount  of  trial  and  error,  the  company 
felt  that  another  method  might  he  more  practicable.  \ 
weighted  steel  framework  was  therefore  introduced,  by 
means  of  which  the  plastics  sheet  was  first  held  between 
two  frames  and  heated,  then  drawn  over  the  mold  and 
stretched  into  shajx-  by  the  weight  of  the  frames.  When 
cooled,  the  entire  framework,  with  the  now  formed  acrylic, 
was  lifted  from  the  mold,  or  form,  with  a  block  and  tackle 
sus|K-nded  from  a  crossbar  above  it.  This  method  eliminated 
the  time-consuming  clamping  operation,  and  made  possible 
the  production  of  a  blouse  form,  comprising  the  area  from 
iitst  l)clow  the  neck  to  the  waistline. 

This  system,  however,  was  discarded  in   1941   and  re- 
placed  with  a  completely  different  technique  by   which  a 
full-sized  form,  including  neck,  shoulders  and  legs,  could  be 
made.  The  newer  method  utilized  a  male  and  a  female  die,     ! 
which  actually  stam|H-d  the  sheet  material  into  shape.  I  "sing 
highly  polished  bronze  forms,  the  work  was  carried  on  in 
an  oven,  the  plastics  sheet  being  placed  over  the  male  por- 
tion, and  the  female  die  then  lowered  from  its  Mi-|>emlc<]  jx. 
sition. 

Although  permitting  the  production  of  larger  and  more 
detailed  units,  this  process  w;i-  found  to  have  a  nuinU-r  of 
drawbacks.  It  was  necessary  to  use  a  large-size  sheet  of 
plastics.  ;md  considerable  wast.njr  \\.i-,  caused  by  tin 

7S  SKITEMBKK   l»l« 


that  the  distorted  material  trimmed  from  the  sides  could  not 
be  reused.  The  models,  being  constantly  in  the  oven  for 
forming,  had  to  be  air-cooled  in  production.  Since  their 
lustre  was  soon  dulled,  it  was  necessary  to  polish  them  re- 
peatedly. Also,  as  curves  flattened  abruptly  where  the  dies 
could  not  meet,  the  sudden  forced  pressure  flowed  the  mate- 
rial unevenly,  causing  distortions  to  appear  on  the  trans- 
parent surface. 

During  the  war  years,  the  company  converted  entirely 
to  essential  production,  but  continued  its  experiments  with 
forming  acrylics.  After  the  war,  resumption  of  peace-time 
work  on  the  same  models  was  facilitated  by  the  fact  that 
the  company,  being  equipped  for  blowing  and  vacuum 
forming,  could  use  a  combination  of  both  methods  on  these 
models,  thereby  practically  eliminating  waste. 

Further  experimentation  was  continued,  however,  result- 
ing, in  the  fall  of  1945,  in  production  of  the  model  which  is 
now  being  made.  The  process  employed  combines  blowing 
and  vacuum  forming  with  drawing  over  a  form.  The 
finished  product  displays  the  results  of  smooth,  even  flow 
of  material,  providing  fine  blending  of  lines  into  the  contour 
of  the  model. 

With  this  system,  the.Jower  portion  of  the  model,  from 
below  the  bust,  is  drawn  on  the  vacuum  box,  in  a  rapidly- 
timed  series  of  operations.  Air  is  withdrawn  from  the 
tank,  automatically  sealing  a  section.  A  female  form  is 
placed  over  the  .material  and  the  section  covered  by  this 
form  is  blown  uniformly  by  placing  pressure  on  the  un- 
covered section.  By  quick  manipulation  of  pressure  valves 
and  careful  watching  of.ga.ges  which  indicate  the  limits  of 
pressure,  the  entire  lower' portion  of  the  model  is  completed 
and  clamped  on  the  vacuum  box.  Pressure  is  then  released, 
blowing  out  the  excess  material  over  a  form  to  make  the 
deep  draw  of  neck,  shoulders  and  back.  Dry  heat  is  found 
to  be  best  for  this  vacuum  forming. 

With  these  methods,  Scheuer  believes  that  the  size  and 
complexity  of  forms  which  can  be  drawn  from  thermoplastic 
sheet  is  limited  only  by  the  size  of  sheet  obtainable.  In  the 
present  operation,  two  units  can  be  made  from  a  36"  by  48" 
sheet,  with  a  leftover  strip  which  is  utilized  elsewhere, 
thus  effecting  economy  in  use  of  material.  END 


Developing?  a  Fabrics  Market 

(Continued  from  page  34) 


fabric  must  contain  50%  openings  in  order  to  transmit 
sound  satisfactorily.  This  requirement  seemed  to  be  rather 
general  throughout  the  industry.  And  despite  the  fact  that 
the  grille  fabrics  previously  used  had  nothing  near  this  per- 
centage of  opening,  and  although  the  Lumite  screen  cloth, 
with  an  opening  of  58%,  was  admittedly  far  too  open  and 
unable  to  mask  the  speaker  cone  properly,  the  "50%  open- 
ing" specification  was  continuously  reiterated.  After  a 
number  of  fabrics  had  been  produced  which  fell  far  short 
of  50%  opening,  it  was  finally  determined  that  what  was 
wanted  was  a  fabric  that  would  transmit  50%  of  the  sound 
impinging  upon  it,  and  that  the  common  test,  eventually 
disclosed  to  us,  was  a  simple  anemometer  test  of  measured 
air  flow.  Much  difficulty  might  have  been  eliminated  had 
an  earlier  understanding  of  "50%  opening"  been  attained. 

Recently  some  intensive  development  work  on  Lumite  has 
been  done  in  the  luggage  field.  Lumite,  at  first  glance, 
seemed  to  be  superior  to  plastics  films  for  luggage  covering ; 
it  offered  genuine  weave  effects  and  a  wide  variety  of  de- 
signs and  colors.  In  addition,  it  contained  potential  extra 
qualities  of  longer  wear,  while  retaining  the  advantages  of 
easy  cleansing,  resistance  to  stains,  and  resistance  to  scars. 

Immediately,  Lumite  ran  into  a  formidable  barrier  in  the 
lack  of  a  suitable  adhesive  to  hold  it  to  the  luggage  case 


Master  Hobs 


Hobbcd  Cavities 


SEPTEMBER  1946 


PLASTICS 


79 


"Lumite"  window  screens  used  on  yacht  resist  rust,  corrosion 

itself.  A  perfect  adhesive  is  absorbed  to  a  certain  degree 
by  each  of  the  two  materials  it  bonds.  Lumite' s  non- 
absorptive  qualities,  which  make  it  stain-proof,  fade-proof, 
and  easy  to  clean,  turned  out  to  be  a  hurdle.  Although 
both  our  own  laboratories  and  those  of  luggage  manufac- 
turers with  whom  we  were  co-operating  conducted  pro- 
longed experiments  with  virtually  all  available  adhesive-,  no 
satisfactory  conclusions  were  obtained. 

Then  began  a  lengthy,  tedious  group  of  experiments. 
based  on  an  assumption  at  the  beginning  that  natural  fibers 
of  some  type  would  have  to  be  included  with  the  .Varan 
monofilaments  in  the  woven  fabric  to  achieve  adhesion. 
Eventually,  a  combination  of  Saran  and  cotton  was  pro- 
duced that  offered  no  difficulties  from  the  standpoint  of 
adhesion.  This  fabric,  however,  seemed  lacking  somewhat 
in  over-all  appearance;  and  the  inclusion  of  a  natural  tilx-i 
had  definitely  eliminated  the  majority  of  the  outstanding 
characteristics  which  had  originally  indicated  the  suitability 
of  I.umitc  fabrics  for  this  purpose.  As  a  consequence,  it 
was  decided  to  abandon  this  application  until  such  time  as 
suitable  adhesives  were  developed  which  would  make  pos- 
sible the  use  of  an  -M-Saran  fabric. 

Fortunately,  a  -uitable  adhesive  for  this  purpose  has  be- 
come available  and  at  the  moment  developmental  work  is 
being  done  by  several  luggage  manufacturers  with  whom 
Chicopee  has  been  co-operating.  The  results  of  this  work, 
not  yet  completed,  will  serve  to  determine  the  construction 
of  the  fabrics  soon  to  be  produced  for  this  application. 

I  his  same  basic  pattern  of  development  has  been  used  in 
several  other  fields,  is  being  used  today,  and  will  unques- 
tionably tx?  used  until  all  |K>— ihle  markets  have  been  ex- 
plored and  suitable  fabrics  have  been  developed.  END 


Five-pound  iron  ball  dropped  over  70.000  time*  on  framed 
section  ol  "Lumite"  screen,  produced  no  denting  or  bulging 


Plastics  Produce  Better  Products 

(Continued  from  page  30) 


bers  of  the  group  of  high  polymers  is  generally  accepted  to- 
day by  chemists  and  physicists.  The  distinctions  arise 
usually  with  re-|K-ct  to  the  end  uses  for  these  materials. 
The  two  high  polymer-  may  Ix-  used  to  complement  one  an- 
other most  effectively.  One  example  of  this  effort  is  the 
development  of  high  strength  adhesive-  for  metal  to  metal 
assemblies  and  metal  to  rubber  assemblies.  Synthetic  re-in- 
rubber  combination-  have  yielded  many  industrial  products 
widely  employed  today.  I  yclized  or  chlorinated  rubber  com- 
positions have  been  quite  out-tanding  in  the  strength  oi'  the 
bond  attained.  The  addition  of  phenol-formaldehyde  com- 
positions to  synthetic  rubber  has  also  attracted  much  in- 
terest. The  hutadiene-acrylo  nitrile  copolymer  has  l>enetited 
most  through  this  addition,  and  there  is  some  evidence  of 
chemical  reactivity  l>etween  the  two  polymers.  Compatible 
in  all  proportions  it  has  been  possible  to  control  the  phys- 
ical properties  at  will  by  varying  the  plastics  or  the  -yn- 
thetic  rubber  content.  With  the  I'iK-S  rubbers,  the  phenolic 
resin  additives  do  not  appear  quite  as  useful. 

From  a  design  |M>int  of  view ,  the  plastics-rubber  combina- 
tions may  complement  one  another  most  effectively.  For 
example,  white  walled  automobile  tires  have  long  been  a 
problem  and  headache  to  tire  manufacturers.  With  all  the 
pre—nre  for  new  tires,  the  production  of  white  walls  has 
been  at  a  virtual  standstill.  Consequently  when  some  enter 
prising  men  in  Detroit  recognized  and  solved  the  problem 
by  designing  and  producing  a  toroidal  shape  of  white  cellu- 
lose acetate  to  be  inserted  under  the  hub  cap.  the  appeal  of 
the  white  walled  tire  was  recaptured. 

The  paper  and  pulp  industry  represents  multi-million  dol- 
lar interests  reaching  many  phases  of  national  economy.  It 
is  significant  that  new  products  and  improved  quality  can  In- 
realized  through  the  introduction  of  a  relatively  small  per- 
ceiitage  of  urea  or  melamine  resin  to  the  paper  stock.  The 
new  technique  involves  not  only  the  treatment  of  the  paper 
stock  by  immersion  into  some  resin  solution,  but  also  the 
addition  of  plastics  into  the  beater  of  the  paper  forming 
machine.  The  resin  does  not  have' to  be  water  soluble.  \s  .1 
matter  of  fact,  water  incompatibility  may  be  preferred  with 
the  resin  being  added  in  the  form  of  an  aqueous  emulsion. 
It  will  deposit,  however,  upon  the  cellulosic  fiber,  and  then 
the  ultimate  paper  or  pulp  stock  will  attain  an  efficient  dis- 
tribution  of  the  plastics.  The  manufacture  of  pulp  preforms, 
with  the  aid  of  phenolic  resins,  proceeds  in  this  manner.  For 
large  molded  |>arts.  an  important  future  is  predicted  for 
resin-pulp  preforms,  fulfilling  the  special  requirement^  of 
custom  molders.  The  lire-distribution  of  resin  and  lilx-i- 
will  greatly  facilitate  flow  through  complicated  molded 
sections.  In  addition,  physical  projx-rties  of  molding-  pro- 
duced from  these  combinations  are  very  good. 

The  addition  of  J  to  5',    urea  or  melamine  resin-   1  ba-ed 
.HI  solids  i   vastly  improves  the  wet  strength  of  j>a|>cr  bags 
and  containers.     For  the  housewife,  this  means  the  axaila 
bility  of  pa|x-r  sacks  which  will  not  decompose  and  fall  apat  t 
when   carrying    wet    produce    home   from   the   market.      I'lic 
relatively    -mall    percentage   of    re-in    present    will    not    in 
ciea-e   the   stiffne—  or   the   moisture   absorbing   qualities  of 
the  |>a|K-r.  and.   in   fad.  the  casual   observer   would  IK'  una- 
ware thai   anything   new    had  Ix-cti  added.     From  a  i|iialil\ 
and  utilitarian  vie\i|xiinl.  the  gams  from  plastics  p]u-  i 
are  unlimited. 

The  number  of  applications  really  has  no  limit.  Pla-tic- 
are  continuing  to  pnnc  their  versatility  by  entering  into 
unn-ual  combination-  with  many  material-  of  construction 
That  thi-  development  will  continue  i-  a  ion-gone  (.inclu- 
sion. 


!•  I.. \XTI1  * 


SKrTKMHKK    I! 


Quince  seed  jelly  releasing  agent  is  applied  with  brush. 
It  dries  into  a  thin  skin  that  may  be  easily  brushed  off 


Make  Your  Own 
Patting  Agent 


V3u  rdckard 


NOTHING  is  quite  so  exasperating  as  a  beautiful  cast- 
ing stuck  fast  in  the  mold,  since  to  remove  it  you 
must  break  the  casting  and  run  the  imminent  danger  of 
marring  the  mold  surface.  Thus,  a  parting  agent  that  will 
release  a  casting  without  the  use  of  compressed  air  or  a 
hammer  and  wedges  is  of  the  greatest  value. 

Quince  seed  jelly  has  performed  this  service  for  Maurice 
Seiderman  of  the  Chemi-Plastic  Laboratories,  Hollywood, 
California,  for  fifteen  years.  He  reports  absolute  success 
with  plaster,  plastics  and  metal  molds.  Seiderman  molds 
reproductions  of  the  human  body,  and  only  an  agent  with 
exceptional  fidelity  to  detail  and  perfect  parting  power 
would  release  the  intricate  casting  of  a  human  nostril,  eye- 
brow, or  ear. 

Unlike  other, releasing  agents,  this  jelly  dries  into  a  thin 
skin  that  may  be  readily  brushed  off  the  casting  with  hand 
or  a  cloth.  Because  it  does  not  .enter  the  pores  of  a  plaster 
casting,  a  light-colored  area  around  the  parting  line  is  elim- 
inated. And,  having  no  chemical  reaction  with  metal,  plas- 
ter or  plastics,  there  is  no  danger  of  sticking,  even  at  high 
temperatures. 

When  heat  is  used  in  polymerizing  resins,  the  releasing 
agents  often  give  trouble.  Both  oven  and  dielectric  heat 
cause  many  organic  liquids  to  give  off  gas  and  bubbles  and 
distort  the  molded  surface.  Lacquers  will  melt  and  cause 
stickage.  Quince  seed  jelly,  on  the  other  hand,  stands  tem- 
peratures up  to  325°  F  and  will  not  give  off  gas,  bubbles 
or  water. 

Since  the  jelly  is  water  soluble,  poly  vinyl  alcohol,  methyl 
cellulose  and  other  water  soluble  resins  cannot  be  used  with 
it.  Resins  which  give  off  water  when  polymerizing,  how- 
ever, are  not  affected. 

Neither  can  it  be  used  in  transfer  or  injection  molding, 

because  the  high  pressures  break  the  film.    In  compression 

molding  where  liquid  resins  are  used,  the  jelly  will  stand  up 

to  5,000  psi.    Preforms  and  powders,  however,  will  tear  it. 

(Continued  on  page  95) 


Manufacturer 
WANTED 

for  sensational  new 
molded  plastic 

LADIES'  BELT 


This  new  and  revolutionary 
item  incorporates  many  unu- 
sual and  distinctive  sales  fea- 
tures. Market  surveys  prove 
enthusiastic  acceptance.  Fully 
protected  by  patents  recently 
granted.  Exclusive  license  ar- 
rangement plus  royalty.  Sam- 
ples can  be  seen  in  our  office. 


BARNES  & 
REINECKE 

INCORPORATED 

DESIGNERS  and  ENGINEERS 

STAFF   OF   181  TWELFTH  YEAR 

230   E.  OHIO  CHICAGO    11 


SEPTEMBER  1946 


PLASTICS 


81 


IN  GOLD,  SILVER  OR  COLORS 


HIGH 

QUALITY 

INJECTION 


MOLDING 


Statistical  Data 


PLASTICS  and  synthetic  resin  shipments  and  consumption  for 
May,  as  surveyed  by  the  Bureau  of  the  Census,  barely 
exceeded  the  total  poundage  for  April,  being  61,235,303  Ib  as 
against  60,930,239  Ib,  the  revised  figure  for  the  previous  month. 
This  lack  of  an  appreciable  increase  was  somewhat  unexpected, 
even  though  it  was  recognized  that  coal  and  steel  shortages, 
which  have  restricted  raw  materials  supplies  and  retarded  plant 
obstruction  and  tooling  programs,  were  bound  to  have  derog- 
atory effects  on  output 

The  fact  that  there  was  a  favorable  balance  at  all  for  May,  in 
the  face  of  decreased  pounds  in  a  number  of  categories,  can  be 
attributed  mainly  to  the  classification  "Phenolic  and  other  tar 
acid  resins,  Molding  materials,"  which  rose  to  13,453,292  from 
12,483,690  Ib  in  April. 

Polystyrene  Levels  Off 

The  rapid  rise  in  the  consumption  and  shipment  of  polystyrene 
over  the  past  several  months  tapered  off  to  a  "mere"  200,000  Ib. 
This  fact,  we  predict,  does  not  mean  that  the  trend  will  not  again 
go  skyward  in  the  coming  months. 

The  vinyls  show  both  decreases  and  increases,  depending  upon 
the  form  in  which  they  are  considered.  Cellulose  acetate  molding 
and  extrusion  materials  show  a  slight  increase,  but  in  other 
classifications  there  was  a  decided  falling  off  for  cellulose 
acetate. 

The  statistics  below  represent  the  shipments  and  consumption 
<>f  plastics  and  synthetic  resins  as  reported  by  77  manufacturing 
companies  and  company  departments.  Data  for  synthetic  resins 
for  protective  coatings  are  not  included.  Shipments,  for  the 
purpose  of  this  report,  include  data  for  plastics  and  resins  manu- 
factured by  the  reporting  companies  or  company  divisions  and 
shipped  to  outside  users.  Consumption  refers  to  the  quantities  of 
plastics  and  resins  manufactured  and  used  by  the  reporting 
ruinpanies  or  company  divisions. 


Plastics  and  Synthetic  Resins  Shipments 
and  Consumption  (Ib) 


Mo,                     April 

Item 

1*46                 1*46 

Cellulose  acetate  and  mixed  eiter  plajticv 

Sheet! 

Continuous  (under  .003  gauge)  

627,583          696,486 

Continuous  (.003  gauge  and  upward)  

591,277          664,833 

424,612        '499,240 

Molding  and  extrusion  materials  

7,251,398      7,181,193 

Nitrocellulose  plastics' 

Sheets  

907,550      1,048,108 

Rods  and  tubes  

624,857         665,853 

Phenolic  and  other  tar  acid  resins 

1,809,303      2,404,966 

1,317,144       1,258,188 

Molding  materials'  I3.4i3.292    1  2,483,690 

All  other  (dry  basis)'  

5,437,693      5,314,081 

Urea  and  melamine  resins 

Adhesives  (dry  basis)  

3,477,628      3,314,027 

Textile  and  paper  treating  (dry  basis)  

890,270      1,012.742 

All  other  (dry  bosh)<  

262,132         186,583 

Polystyrene'  

5,159798      4,950,626 

Vinyl  resins 

Sheeting  and  film'  

2,375,298      2,243,370 

Textile  and  paper  coating  resins  (resin  content). 

1,397,337      1,436,258 

Molding  and  extrusion  materials  (resin  content). 

4,665,924      5,265,325 

Adhesives  (resin  content)'  } 
All  other  (r»wn  content)'  / 

•2,187,521     >1,804,105 

Miscellaneous  plastics  and  resins 

Molding  and  extrusion  materials',  •  

5,537,499      5,439,045 

All  other  (dry  bosh)',  •  

2,837,187    '3,061,520 

TOTAL 61,235,303    60,930,239 


•*.*>•.<!.  'l-clud.i  Mlm,  platnclim,  end  •it.no'.n.  t.d.d.1  **•  lor  Mtetftn 

cooling  rMtm.  'Conool  b.  riwwfl  upefotolr  *MMHl  «MSMtog  tftilOtm  el  MMeM 

•MoblMMMnH.  'Proportion  ol  .«H»ot«.  2.1%.  •hcMM  4ate  far  «M  tlidcii,  «r»o 
and  •lllB^bn,  acrylic  ocid,  and  miK»llon»ovt  eioMh 
data  far  oUroUim  rxirn,  acrylic  ocld,  •«!•»  mint,  i 


82 


f» i,. tsn<  * 


SKITKMBER  1946 


ENGINEERING 

jdett&i 

By  LEWIS  WINNER 

Market  Research  Engineer 

Resins  as  Binders 

In  probing  the  effectiveness  of  synthetic  resins  as  binders, 
plastics  researchers  have  discovered  a  variety  of  unusual  applica- 
tions, not  only  for  bonding  of  an  assortment  large-surface  ma- 
terials but  for  cementing  of  small  particles  on  large  and  small 
areas.  For  instance,  Gaetano  F.  D'Alelio,  Northampton,  Mass., 
uncovered  many  unusual  factors  during  his  work  on  the  bonding 
of  abrasives  on  plastics.  He  found  that  copolymers  of  diallyl 
maleate  and  a  vinyl  aryl  compound  were  excellent  binders  for 
abrasive  materials. 

Phenolic  and  urea-aldehyde  resins  have  been  used  as  binders 
for  abrasives.  In  the  curing  of  these  resins,  byproducts  form  and 
interfere  with  accurate  control  of  shapes  molded.  To  overcome 
this  problem,  some  experimenters  have  cast  a  mixture  of  abrasive 
particles  and  a  polymerizable  liquid  binder,  but  this  process  often 
requires  several  days  and  results  in  substantial  shrinkage  of 
material.  Mr.  D'Alelio's  method  appears  to  have  corrected  these 
difficulties,  providing  exactly  shaped  abrasive  articles,  in  little 
time. 

In  producing  molded  abrasive  articles,  a  heat-convertible, 
soluble  and  fusible  partial  copolymer  of  diallyl  maleate  and 
styrene  is  prepared  first.  This  (the  base  material,  a  free-flowing 
white  powder),  is  mixed  with  a  polymerization  catalyst  and 
dissolved  in  a  mixture  of  a  liquid  copolymerizable  monomer 
and  acetone  or  other  volatile  liquid  which  may  be  a  solvent  for 
the  copolymer.  The  mixture  forms  a  viscous  solution  which  is 
then  thoroughly  mixed  with  abrasive  particles.  The  resultant 
pasty  mass,  dried  to  remove  the  volatile  liquid,  forms  a  dry 
crumbly  mass ;  this  is  a  uniform  mixture  of  abrasive  particles 
in  a  heat-convertible  binder  composition,  and  may  then  be  molded 
under  heat  and  pressure. 

Abrasive  paper  or  cloth  may  also  be  made  by  this  process. 
To  produce  these,  a  partial  copolymer  of  diallyl  maleate  and 
styrene  or  other  vinyl  aryl  compound,  together  with  a  catalyst, 
is  dissolved  in  a  mixture  of  the  liquid  monomer  and  volatile 
solvent  for  the  copolymer,  then  thoroughly  mixed  with  abrasive 
particles.  Sufficient  solvent  must  be  used  to  provide  a  varnish- 
like  mass,  which  is  then  poured  on  the  paper  or  cloth.  The 
abrasive  particles  can  be  located  electrostatically  so  that  the 
major  axes  of  the  particles  fall  substantially  perpendicular  to 
the  surface  of  the  sheet. 

In  the  samples  prepared,  carborundum  (No.  ISO)  was  used  as 
the  abrasive. 

The  binder  is  said  to  be  quite  tough  and  highly  resistant  to 
heat,  water,  alcohol,  mineral  oil,  glycerine,  etc. 

Effective  Sealers 

In  studying  the  uses  of  plastics  as  a  binder,  researchers  have 
also  found  that  plastics  compositions  can  be  used  as  effective 
sealers.  Such  an  application  was  developed  by  Herman  E.  Bal- 
lard,  Berkeley,  Calif.,  who  used  chloroprene  polymers  (neoprene) 
to  seal  mineral-oil  valve  or  pump  glands. 

Butadiene  copolymer  particles  have  been  used  for  this  purpose. 
Unfortunately,  however,  the  tensile  strength  of  these  particles 
weakens  while  swelling  at  high  oil  temperatures.  The  chloro- 
prene polymers  retain  their  tensile  strength  in  mineral  oils  at 
temperatures  as  high  as  300°  F. 

The  new  composition  is  prepared  by  mixing,  at  approximately 
300°  F,  about  18.75%  white  petrolatum  and  6.25%  aluminum 
stearate  and  allowing  it  to  cool  at  room  temperature.  About 
75%  chloroprene  polymer  is  then  fed  to  this  mixture,  followed 
by  mixing  with  an  ordinary  mortar  and  pestle.  The  elastic 
particles  of  the  chloroprene  polymer  are  suspended  in  the  gel 
of  aluminum  stearate  and  petrolatum,  which  does  not  lower  their 
tensile  strength,  yet  lubricates  them  so  that  they  flow  over  one 
another  when  pressure  is  applied.  It  appears  that  while  the 
composition  flows  under  relatively  low  pressure  through  the 
filling  apertures  of  the  pump  glands,  the  particles  interlock  at 
the  higher  pressures  and  then  act  not  as  particles,  but  as  a  solid. 


QUICK 
DELIVERY 


Standard    Mold    Bases 
for  Plastic  Molding 

We  can  fill  your  requirements 
—quickly!  D.M.E.  Standard  Mold 
Bases,  and  Plates  save  you  time 
and  money.  Engineered  by  ex- 
pert mold  designers  .  .  .  finest 
precision  workmanship. 

INJECTION  MOLDING  .  .  .  D.M.E.  Bases  fit 
all  standard  machines  .  .  .  save  as  much  as 
$100  per  mold  on  labor  and  materials  .  .  . 
cut  engineering  time  as  much  as  20% 
.  .  .  save  week  to  10  days  in  time  required 
to  get  new  mold  ready  .  .  .  have  about 
60%  salvage  value. 

COMPRESSION  AND  TRANSFER  MOLDING 
.  .  .  Large  stock  of  standard  plates  and 
other  details  for  immediate  delivery. 


Mail  Coupon  Today  for  FREE  Catalogue 


Detroit  Mold  Engineering  Co., 

6686  E.  McNichoU  Rd.,  Detroit  12,  Mich. 

Please  tend  me  your  FREE  catalogue  of  standard  mold  bases, 

and  plates  and  details  for  plastic  molding. 


NAME 


COMPANY 
ADDRESS   _ 


(Ml 


-    DETROIT      MOLD 
ENGINEERING     COMPANY 


6686   E.   McNICHOLS  RD. 


DETROIT   12,   MICHIGAN 


SEPTEMBER  1946 


PLASTICS 


MACHINES   THAT   NEED   NO   POWER 

The  Famco  Squaring  Shear  ( above )  is  an  all  'round 
saver.  Requires  small  investment  .  .  .  no  electric  power  .  .  . 
it's  simple  to  install  .  .  .  has  easy  gauge  settings.  This 
Famco  Shear  will  cut  up  to  18  gauge  mild  steel.  Made 
in  five  sizes:  22",  30",  36",  42"  and  52"  cutting  widths 
(three  largest  have  "hold  down"  attachment).  All  models 
are  equipped  with  front,  back  and  side  gauges.  Write 
today  for  descriptive  folder. 

Famco  Foot  Prettei  for  light  forming  and 
stamping  are  available  In  10  models  (for 
bench  or  floor  mounting).  Low  in  cost. 

Famco  Arbor  Prettet,  In  32  mod*li,  bench 
and  floor  mounting,  will  deliver  up  to  15 
font  pressure  .  .  .  require  no  electric  power. 

FAMCO   MACHINE   CO.,   1325  18th   ST..  RACINE,  WISCONSIN 

f a  mco 

- machines 


COST 

(CUTTING) 


SQUARING  SHEARS  •  ARBOR  PRESSES  -  FOOT  PRESSES 


ADJUSTABLE  FLY  CUTTER 

Two  models  cut  quick,  clean,  accurate  holes  within  a 
2Vl"  to  10"  range,  up  to  1"  thick.  Cross-section  of  cut 
has  appearance  of  letter  "W  with  each  blade  taking 
out  its  own  side.  Unique  angles  at  which  blades  are 
held  and  new  grinding  technique  oo  high-speed  steel 
cutting  blades  assures  smooth  clean  cuts.  Shank  is 
heat-treated.  Removable  pilot,  hardened  and  ground, 
permits  use  of  lead  drills. 

foe  complfl*  information   tall  four  Clark  Cvrttr  Jobb.r 
today  or  writt  lor  catalog  ~  ' 


In  one  ol  the  te>N  xivi-n.  the  seals  withstood  a  prc-Min  .it 
18.000  I-M. 

It  is  possiMc  In  us,-  calcium  >u-arak-  or  other  soaps,  either 
water-soliihle  or  insoluble,  in  place  of  the  aluminum  stearate. 
And  in  jilai-e  of  the  |>etrolatum.  a  mineral  oil  that  has  been  made 
plaMi.  hy  -naps,  hard  asphalt  or  mineral  wax.  or  animal  and 
vegetable  waxes,  may  be  used. 

Insulation  Problems 

The  use  of  resins  as  an  insulating  coating  for  wires  lias  ri.-- 
ivivnl  u  iiU-pread  approval  from  insulation  specialists,  not  only 
because  of  the  high  insulating  properties  provided,  but  InvaiiM- 
ol  the  resin's  tenacity.  The  latter  characteristic,  however,  in- 
troduced quite  a  problem  during  the  war,  for  it  became  in- 
crasindjr  difficult  to  -.trip  wires  quickly  and  it  was  no 
to  develop  methods  anil  solvents  that  would  facilitate  stripping 

In  a  recent  di-cus>ion  of  this  problem  K.  J.  Klynn  and  (>.  \\ 
YOIIIIK.  of  (ieneral  Electric,  said  that  potassium  iodide  had  Ix-en 
found  effective  in  removing  resin  coatings  The  iodide,  heated 
in  a  porcelain  crucible  to  730°  C.  removed  alkyd  resin.  celluL.se 
acetate,  phenolic  resin  and  alkyd  modified  nylon  wire  coating 
It  was  m-iess.iry  to  immerse  fine  wires  in  the  iodide  for  only 
about  'f,  sec.  and  wipe  with  a  clean  cloth.  Heavier  wires  re- 
quired up  to  2  sec  immersion  for  stripping. 

Other  Recent  Developments 

Efforts  to  use  plastics  to  replace  metals  and  other  mat. 
in  the  interests  of  economy  and  increased  efficiency,  have  re- 
sulted  in  several   unique  developments. 

Among  them  is  a  plastics  rivet  developed  by  Henry  Kearns, 
Pasadena.  Calif.  The  rivet,  of  the  blind  type,  has  a  hollow  pin 
that  is  split  to  form  several  retaining  tongues.  A  cylindrical 
plunger,  attached  to  the  head  of  the  rivet,  is  forced  through  the 
hollow  pin  and  serves  tit  lock  the  retaining  tongues. 

\  two  -die  unit  is  used  to  mold  this  rivet,  each  die  having  a 
central  plunger.  In  one  of  the  dies  the  plunger  is  used  to  form 
the  plunger  of  the  rivet,  and  the  hollow  bore.  The  plunger  in 
lln-  second  die  is  used  for  ejecting  the  completed  rivet,  which,  it 
is  said,  will  unite  two  sheets  of  material  firmly  and  solidly. 

Plastics  has  also  been  widely  used  in  expellent-type,  pencil- 
like  containers  for  medicinal,  hygienic  and  cosmetic  subst 
Shrinkage  and  warpage  effects  prevalent  in  earlier  type  con- 
tainers have  now  IK-CII  ininimi/ed.  In  one  development  by  John 
\V  \ndcrson.  Danhury.  Conn.,  slotted  walls  have  been  used  to 
provide  the  necessary  frictional  cling  between  telescoping  tubes, 
and  reduce  the  effects  of  container  warpage. 

Curved  side  walls  have  also  I>een  used  in  this  container  de- 
velopment. This  type  %vall  provides  a  yielding  spring  action  that 
is  not  affected  by  ordinary  warpage. 

Cellulose  acetate,  utilized  for  most  types  of  these  com. 
was  found  to  IK-  sufficiently  resilient  when  formed  into  a  curved 
wall  ',n"  thick. 

Kills  and  stretchers  of  umbrellas  arc  being  made  of  plaMi.  -. 
in  a  development  perfected  by  Sol  Isler.  New  York.  Metal  is 
used  only  in  the  hinges  and  it  is  planned  to  replace  these,  too, 
with  plastics,  at  an  early  date. 

The  ribs  and  stretchers,  made  in  the  form  of  rods,  are  fitted 
into  metal  collars. 

Although  the  plastics  rods  are,  of  necessity,  flexible,  they 
ap|K-ar  to  l>e  rugged  enough  to  withstand  repeated  opening  and 
closing  operations 

Audio-response  Studied 

Some  interesting,  vinyl  plastics  record  audio-response  studies 
are  being  conducted  by  several  consulting  groups.  It  appears 
that  the  high-freqiicni  y  needle  scratch  in  the  plastics  pressings 
for  popular  use  is  much  more  pronounced  than  it  is  in  shellac. 
(Thousands  of  records  are  run  off  a  "master"  for  popular  use, 
while  only  about  two  hundred  are  pressed  from  a  master  for 
broadcast  transcription  application).  The  accented  groove  re- 
sponse a  due  to  the  groove-wall  structure  which  seems  to  am- 
plify reproduction  of  the  needle  action. 

Potential  solutions  of  the  problem  are  of  a  plastics  and  elec- 
tronic nature;  preparation  of  a  different  type  of  groove  stru 
and  development  of  a  scratch-elimination  system  which  does  not 
affect  the  high-frequency  response  of  the  recording.  The  ef- 
ficiency of  the  latter  solution  was  indicated  in  a  recent  demon- 
stration in  which  the  scratch  was  eliminated  but  reproduction  of 
the  "highs"  of  musical  instruments  was  unaffected.  IND 


FI.ASTiC-8 


SKITKMBKR  ! 


overseas 


The  all-time-high  world  consumer  demand  for  all  types  of 
plastics  commodities  is  creating  a  problem  of  major  proportions 
for  the  British  plastics  industry  as  a  whole.  The  industry's 
present  total  productive  capacity  is  proving  insufficient  to  meet, 
simultaneously,  home  and  overseas  requirements  on  anything 
resembling  an  adequate  scale,  despite  working  more  overtime 
than  ever  before. 

At  the  same  time,  all-round  plant  expansions  and  extensions 
are  proceeding  at  an  extremely  slow  pace  because  of  drastic 
shortages  of  accommodation,  manpower  and  machinery.  Accord- 
ingly, British  materials  manufacturers,  molders,  laminators, 
fabricators  and  merchandisers,  urged  by  their  Government  to 
accept  orders  from  all  over  the  world  to  make  good  Britain's 
1946  export  target  figure  of  $2,800,000,000  worth  of  goods,  are 
having  a  thin  time  battling  with  overbooked  delivery  dates, 
with  no  sign  of  being  in  a  position  to  catch  up  with  them  for 
several  years. 

Leading  Britsh  plastics  exporters,  out  to  capture  the  plastics 
markets  of  the  world,  are  launching  a  new  export  company  for 
the  group  selling  of  a  wide  range  of  plastics  merchandise  in 
overseas  markets. 

Formed  with  the  co-operation  of  the  Export  Promotion 
Branch  of  the  British  Board  of  Trade,  this  company  will  collab- 
orate with  the  non-profitmaking  British  Export  Trade  Research 
Association  in  an  effort  to  rind  new  outlets  in  foreign  coun- 
tries, as  well  as  in  organizing  plastics  group  exhibitions  at 
forthcoming  international  trade  shows. 

New  Products  and  Producers 

A  new  gossamer  wool  material  combining  finely-spun  worsted 
yarn  with  a  supporting  plastics  carrier  thread  extracted  from 
peanuts,  is  now  being  produced  in  Britain. 

Weighing  only  1  oz  to  the  sq  yd  and  equal  to  the  finest 
quality  pure  wool,  this  extremely  lightweight  fabric  is  claimed 
as  an  ideal  material  for  lingerie  and  certain  fashion  requisites. 

The  British  Dunlop  Rubber  Co.  recently  started  two  new 
companies  for  the  fostering  of  large-scale  commercial  develop- 
ment of  textile  plastics. 

The  first,  named  Dunlop  Clothing  &  Weatherproofing,  Ltd., 
is  to  be  devoted  to  increasing  the  use  of  plastics  in  the  production 
of  tweeds,  worsteds  and  other  clothing  materials,  and  the  second, 
Dunlop  Special  Products,  Ltd.,  will  specialize  in  the  manufacture 
of  plasticized  wearing  apparel. 

One  of  the  latest  British  developments  in  the  practical  appli- 
cation of  plastics  to  housing  is  a  Bakflite  laminated  wallcovering, 
with  an  interwoven  wire  mesh  as  a  heating  element. 

According  to  available  information,  the  new  wallcovering 
evenly  diffuses  warmth  over  an  entire  room,  has  surfaces  as 
decorative  as  any  wallpaper  or  rare  wood  panels,  is  easily 
cleaned  and  not  readily  defaced. 

Warerite  Ltd.,  Herts,  England,  one  of  the  companies  com- 
prising the  British  Bakelite  Group,  has  announced  that  through 
the  successful  application  of  laminated  plastics  veneers  to  ex- 
panded synthetic  rubber  cores  it  has  been  successful  in  producing 
a  novel  type  of  lightweight  plastics  board  material,  having 
exceptional  strength. 

Claiming  that  the  new  material  possesses  valuable  hygienic 
properties  and  is  resistant  to  heat,  water,  acids,  alcohol,  is  easy 
to  clean,  and  will  neither  chip  nor  crack.  Warerite,  Ltd.,  lists 
among  its  potential  uses  hospital  furniture,  trays,  and  other 
applications  within  hospitals. 

For  Harried  Commuters 

In  an  effort  to  make  straphanging  on  overcrowded  suburban 
trains  more  comfortable,  London  district  railways  experimentally 
introduced  a  new  kind  of  shock-absorbing  strap,  comprised  of  a 
spring-loaded  universal  spiral  wire  enveloped  in  rubberized 
plastics. 


You're  Assured  of 

DEPENDABLE 

Heavy  Duty  Compression 

MOLDS 

with 

AJAX  61  STEEL 


HERE'S  WHY! 

AJAX  "61"  is 


ELECTRIC   FURNACE    QUALITY 
EASILY   MACHINED 

FREE   OF   FLAKES,  CRACKS 
and    STRINGERS 


Ajax  "61"  Steel  in  Ajax  forged  mold  blanks  means 
real  economy  in  compression  molds  specified  for 
heavy  duty.  Ajax  Sfeel  is  hardened  to  your  job  speci- 
fication and  is  guaranteed  free  of  defects  in  material 
and  workmanship.  Ajax  is  proud  of  its  record  and 
reputation  among  plastic  molders  for  trojble-free, 
high  quality  mold  steel. 

We  invite  you  to  bring  your  mold  steel  problems  to 
AJAX  Steel  and  Forge  Company. 


Valuable 


Write  our  Service  Department  for 
your  copy  of  the  famous  "AJAX 
BLACK  BOOK."  Full  of  useful  in- 
formation, steel  weights,  standard 
specifications,  conversion  tables. 
etc. 


Booklet 


SEPTEMBER  1946 


I'LASTMCS 


85 


WE  are  now  granting  license 
and  furnishing  equipment  for 
making  this  sensational  new 
folded  plastic  box. 

Protection,  reuse  and  display 
combine  in  these  rigid  boxes 
that  are  made  from  cellulose 
acetate  or  vinylite  and  which 
require  no  cement  or  solvent 
to  hold  them  together. 

THE  BOX  THAT'S  NEVER  THROWN  AWAY 

.10 II  \    II .  OXLEY    CO. 

>t;iniil;i.    I  ill  «T    &    lt<-«i  |;n  <-r 
V\    V  I  I    II  I  0\\   N 


Boicf-Cnne  Power  Teoli  hive 
been  dfMgnrd  (or  ready  adaptabil- 
ity U  a  wide  range  of  project*. 
Thin,  fewer  machines  are  needed 
to  meet  all  your  requirement*. 


Sturdily  built  and  tafety-engi- 
niertd  Bolce-Crane  tooli  are  avail- 
able for  Moret  of  machining  and 
flnlihlng  operation!.  There  are 
band  >aw<  and  jig  t  a  w  t  for 
itraight  and  contour  cutting,  and 
equipment  for  drilling,  routing, 
tapping,  thaplna.  turface  and  end 

Klndina  (removing  (lath),  lurtac- 
I.   polithing.   etc.   Shown   li  the 
Bolce-Crane  Jig  Saw. 


The  Ideal 

Power  Toofs 

for  the 

Plastic 

Industry 

BOICE-CRANE 


Writ*  lor  /re*  48  paq*  catalog 

BOICE-CRANE  COMPANY 

911   Control  Av.nue  Toledo  A.  Ohio 

lei  Men 
feBMdllo  §j|^Mrl 


Fitted  originally  to  about  a  half-dozen  cars,  the  plastics  device 
soon  proved  to  be  a  marked  advance  over  the  hitherto-used 
unyielding  strap,  and  is  to  be  more  widely  adopted. 

Offcer  Developments 

British  domestic  equipment  manufacturers  are  now  fitting 
the  dust  receivers  of  their  vacuum  cleaners  with  disposable 
plastics  containers.  When  filled,  these  containers  can  be  easily 
removed  and  replaced  by  new  ones  at  small  cost. 

This  innovation  is  welcomed  by  the  servantless  British  hou-e- 
wife,  as  it  dispenses  with  the  dirty  and  unpleasant  task  of  shaking 
out  and  reinserting  dusty  bags. 

Considerable  progress  has  been  made  lately  in  Britain  in  the 
provision  of  plastics-reinforced  container  protection,  by  mixing 
paper-making  fibres  with  vinyl  copolymer  fibres. 

When  used  for  the  transportation  of  hardware,  pottery,  elec-  < 
trical  machinery  and  allied  merchandise,  containers  protected  in 
this  manner  showed  improved  strength,  folding-endurance  and 
abrasion-resistance. 

New  details  have  been  revealed  about  the  submarine  in  which 
the  Belgian  scientist,  Professor  Piccard,  intends  to  explore  the  • 
depths  of  the  Atlantic  Ocean. 

It  now  appears,  that  while  experimenting  with  methyl  nictlia- 
crylate  for  portholes,  Professor  Piccard  was  impressed  by  the 
exceptional  strength  of  this  plastics,  and  decided  to  use  it  as  the 
constructional  material  for  the  entire  construction  of  his  sub- 
marine, instead  of  the  8"  thick  steel  plates  from  which,  accord- 
ing to  report,  he  had  previously  planned  to  build  it. 

The  European  countries  are  becoming  increasingly  pla- 
minded,  and  factories  are  springing  up  practically  everywhere  to 
meet  the  enormous  demand  for  molded  and  fabricated  plastics. 

At  the  recent  International  Trade  Fair  in  Paris,  Europe's 
latest  advances  in  plastics  were  much  evidenced  in  all  types  of 
products,  ranging  from  plastics-encased  radios  and  electric  gad- 
gets to  plastics  lampshades  and  kitchen  utensils. 

The  wide  and  varied  domestic,  industrial  and  medical  appli- 
cations of  plastics  were  vividly  demonstrated  to  the  British 
public  at  the  recent  Chemical  Research  Exhibition  in  London. 
Among  the  many  interesting  exhibits  on  view,  interest  was 
particularly  aroused  by  an  ophthalmoscope,  using  ingeniously 
shaped  Persptx  plastics  lenses  for  carrying  illuminating  "cold 
light"  into  the  human  eye. 

Australian  Plastics  Field 

Plastics  progress  in  Australia  is  reflected  in  several  develop- 
ments reported  recently  from  that  country.  On  the  production 
front,  use  of  up-to-date  methods  is  indicated  by  the  distribu- 
tion in  a  wide  range  of  capacities,  of  Mtgatherm  electronic 
heating  units,  manufactured  by  the  Federal  Telephone  and  Radio 
Corp.  One  large  manufacturer.  General  Plastics,  Ltd.,  produc- 
ing casein  buttons  and  kindred  lines,  has  recently  doubled  its 
capitalization,  thereby  greatly  increasing  its  capacity. 

Plastics  shoes  recently  reached  the  Australian  market,  from 
overseas  sources,  but  a  short  time  later,  shoes  of  Australian 
manufacture  appeared  in  cjty  footwear  shops,  at  least  two  of 
the  manufacturers  producing  women's  shoes  of  vinyl  material. 
Two  types  are  at  present  available — a  "wrap-over"  beach  sandal 
which,  being  proof  against  the  effect  of  salt  water,  is  proving 
very  popular,  and  is  made  in  translucent  silver  and  in  crim-on. 
The  second  type  is  a  formal  shoe  of  silvery,  transparent  plastics 
with  black  matte-finish  trim,  open-toed  and  with  rows  of  small 
perforations  providing  additional  trimming  and  ventilation. 

The  first  annual  dinner  of  the  Plastics  Institute  of  Australia, 
which  was  held  in  Sydney  recently,  was  attended  by  69  leaders 
of  the  industry. 

A  problem  of  the  Sydney  Metropolitan  Water  and  Sewerage 
Board  was  that  of  provision  of  corrosion  of  steel  fans  used  for 
ventilation  exhaust  purposes  at  a  sewer  outlet.  Despite  protective 
coatings,  a  high  proportion  of  hydrogen  sulphide  in  the  atmos- 
phere caused  formation  of  dilute  sulphuric  acid  on  the  metal, 
necessitating  frequent  replacement  of  the  fans.  After  careful 
investigation  of  the  problem,  Densified  Woods  Pty  .  Ltd.,  a 
plastics  firm  in  Sydney,  produced  a  fan  made  from  phenolic 
impregnated  satinwood.  low  pressure  molded  into  shapr.  with 
nuts  and  bolts  of  a  plastics-impregnated  laminate.  The  fan 
circulates  from  20,000  to  30,000  cu  ft  of  air  per  min,  and.  since 
its  installation  last  year  has  been  in  completely  satisfactory 
o|KTHtiim  fur  J4  hr  a  day.  >  s: 


86 


SKPTK.MHKR  1946 


• 


IHDOSTET 


A  public  test  designed  to  provide  consumers  with  a  convinc- 
ing demonstration  of  the  strength  of  certain  plastics  was  re- 
cently conducted  by  Gits  Molding  Corp.,  Chicago,  at  Wrigley 
Field.  Phil  Cavarretta,  of  the  Chicago  Cubs,  assisted  in  the 
demonstration  by  batting  a  flashlight  with  housing  of  Dow 
Ethocel  (ethyl  cellulose)  and  made  by  the  Gits  company,  across 
the  street  with  a  powerful  drive.  After  this  test,  a  trailer-truck 
and  load,  weighing  approximately  30,000  Ib,  was  run  over  nine 
of  the  flashlights.  These  drastic  demonstrations  are  said  to  have 
produced  not  one  crack  in  the  plastics  housing,  and  there  was 
no  indication  of  its  breaking. 


The  opening  of  a  Buffalo,  N.  Y.  office,  has  been  announced 
by  Worcester  Moulded  Plastics  Co.,  Worcester,  Mass.  The  new 
office  is  at  120  W.  Chippewa  St.,  with  Wilson  H.  Townes  as 
manager.  , 

Further  expansion  of  the  General  Electric  Chemical  Depart- 
ment is  to  be  effected  with  the  formation  of  a  metallurgy 
division,  with  headquarters  at  Pittsfield,  Mass.,  according  to 
recent  announcement  by  Dr.  Zay  Jeffries,  company  vice  presi- 
dent and  general  manager  of  the  Chemical  Department.  The 
new  division  represents  the  third  operating  unit  to  be  incorpo- 
rated in  the  Department,  and  will  handle  the  sale  of  various 
types  of  permanent  magnets  and  metallurgical  products. 


A  widening  range  of  packaging  uses  is  being  found  for 
Pliofilm,  produced  by  Goodyear  Tire  &  Rubber  Co.  FF  Pliofilm, 
described  as  being  resistant  to  brittleness  at  temperatures  as  low 


as  — 20°  F  while  retaining  its  imperviousness  to  grease  and  oils, 
and  its  moistureproof  and  transparent  qualities,  is  being  used  in 
the  marketing  of  frozen  pie  dough.  And  a  new  packaging  tech- 
nique employing  Pliofilm  has,  according  to  announcement,  made 
possible  the  non-refrigerated  air  shipment  of  shrimp.  Pre-cooled 
to  a  temperature  just  above  32°  F,  the  shrimp  is  packed  in 
P/io/i/m-lined  containers,  which  are  heat-sealed,  then  placed  in 
lightweight  insulated  shipping  boxes.  Temperature  control  tests 
on  this  method  of  shipping  shrimp  are  said  to  have  shown  a  rise 
of  only  7/10°  per  hr  when  the  outside  temperature  is  70°. 


Designed  to  enable  parent-shoppers  actually  to  see  how  a 
new  shoe  will  conform  to  the  bony  structure  and  flesh  of  the 
child's  foot,  Step  Master  Shoes,  Inc.,  Greenup,  111.,  has  an- 
nounced a  Window  Fit  method  of  fitting  shoes  to  children's 
feet. 

This  consists  of  transparent  vinyl  plastics  vamp  shoes,  built 
on  the  company's  standard  last,  embodying  every  size  and  half- 
size  through  the  "growing  range,"  through  which  the  customer 
can  see  which  size  allows  proper  room  for  growth  of  the  child's 
foot. 

A  new  resin  emulsion,  designed  for  use  in  the  plasticizing  of 
polyvinyl  chloride  latexes,  such  as  the  Geon  latex  series,  and  for 
Buna  N  films,  has  been  announced  by  Resinous  Products  &. 
Chemicals  Co.,  Philadelphia.  Known  as  Emulsion  G-25,  the  new 
product  is  an  aqueous  dispersion  of  Paraplex  G-25,  and  is  de- 
scribed as  being  characterized  by  non-migration,  permanence, 
resistance  to  heat  and  hot  oil,  and  by  flexibility  at  low  tempera- 


THE  CEE-BEE  MFG.  CO. 

PLASTIC  SLITTING,  CUTTING  &  SHEETING    PROBLEMS   SOLVED 


We  slit  all  types  of  plastic  materials  including  cellophane,  acetates,  etc., 

from   1/16  inch  to  75  inches  in  width. 
We  interleave  plastics. 

We  are  equipped  to  slit  up  to  100,000  yds.  per  day. 
Prompt  service. 
Storage  space  available  —  Equipped  with  railroad  siding. 


WE  ALSO  SHEET  PLASTIC  MATERIALS  FOR  PRESS 
POLISHING  USED  IN  THE  LADIES  HANDBAG  &  SHOE 
TRADES  AND  FOR  ALL  OTHER  PURPOSES. 

Write  to  Us  About  Your  Plastics  Cutting.  Slitting  and  Sheeting  Problems 

Tel.  Ev.  7-8331 

76  N.  4th  ST.  BROOKLYN  11,  N.  Y. 


SEPTEMBER  1946 


PLASTICS 


87 


SLITTING 
CUTTING 

and  Rewinding  of  All 

•PLASTIC  FILM  and 
•COATED  MATERIALS 

from  Vm"  and  Upward  in  Width 

•  PINKING 

•  SCALLOPING 
•FANCY  EDGES 

•  CORDING 

•  WELTING 

Complete  Service 

INQUIRIES  AND  PROBLEMS 
ATTENDED  PROMPTLY 

WRITE  OR  PHONE  Now.' 

BENJAMIN  GOODMAN.. 

69  FIFTH  AVE.,  N.Y.  C. 

,   8533 
ALGONQUIN   4 


8536 


For  PANTOGRAPHIC  ENGRAVING 

ON  PLASTICS 

Panto      Engravers, 

rugged  and  precision-built, 
for  accurate  and  clean-cut 
engraving  on  plastic 
and  metal  products. 
Depth    Regulator. 
available    with    all 
models,   produces  a 
uniform  depth  of  engraving 
on    irregular    and    curved 
surfaces.     Forming    Guide, 
on  the  UE-3  only,  for  use 
on  curved,  spherical,  and 
beveled  surfaces. 

Engraving  cullers,  master  copy  type,  fixtures,  and  end- 
less round  bells,   lor  all  types  of  engraving,   die  and 

mold  cutting  machines. 


MODEL  CG  GRINDER 
{or  quick  and  accurate 
sharpening  of  engraving 
and  routing  cutters. 

9  Catalog 
on  request 


H.  P.  PREIS  ENGRAVING  MACHINE  COMPANY 
IME  SUMMIT  STREET  NEWARK  4.  NEW  JERSEY 


PANTO  MARKING  EQUIPMENT 


•     tures.    Combinations  of  the  emulsion  can  be  pigmented  to  gh 
coated  fabrics  a  variety  of  colors,  and  ease  of  application  a 
absence  of  flammable  or  expensive  solvents  are  listed  as  fact* 
widening  its  range  of  applications  in  the  plasticizing  field. 


A   mill   site   has   been   purchased  by   Brookneld   Plastic 
Rubber  Co.,  which  was  recently  organized  in  East  Broolcfie 
Mass.   According  to  Hans  Sacks,  treasurer,  the  company  plai 
to   manufacture   plastics    products    as    soon    as    the    necessai 
machinery  can  be  obtained. 

Recommended  by  its  makers  for  the  making  of  molds  f« 
casting  low-temperature-fusing  plastics,  wax  molds  for  precisil 
casting  process,  rubber  molds,  and  various  others,  a  new  alloj 
called  Moldaloy,  has  recently  been  introduced  by  TrethavM 
Associates,  New  York  City.  Characteristics  listed  for  the  prod 
net  include:  Melting  point  of  430°  F,  hardness  22  Brine!!,  coa 
pression  strength  of  8000  psi,  tensile  strength  11,500  psi,  shrink 
age  approximately  .001"  per  inch. 

A  change  of  corporate  name  has  been  announced  by   Kei 
D.-nta!  Mfg.  Co.,  6081-6095  Twelfth  St.,  Dctn.it.  which 
to  be  known  as  Kerr  Mfg.  Co. 


Announcement  has  been  made  by  Stanley  Sapery  that  h 
has  resigned  from  the  sales  managership  of  Victor  Metal  Prod 
ucts  Corp-t  Brooklyn,  N.Y.,  to  establish  his  own  business  as  sab 
representative,  at  11  E.  44  St.,  New  York  City.  Among  hi 
activities  he  plans  a  packaging  service,  specializing  in  plastic: 


Perfection  of  a  new,  clear  vinyl  plastics  dim  for  flameproof 
ing  fabrics,  has  been  announced  by   M.  A.   Dorian,  mat. 
the  textile  division.   Roxalin   Flexible   FiniOie-.   Inc..   Kli/Lilx-tl 
-V   ).    Its  use  is  said  to  render  unnecessary  application  of 
separate  base  coat  and  top  coat. 

In   liquid   form,   thi>   new    coating   is  deposited  on   the   labri 
with   conventional   spreading  or   knife-coating   machines  and  1 
>aiil  to  yield  a  hard,  high  bl<ick-resi*tancc,  absolute  flani* 
ne--.  and  to  he  high  in  resistance  to  moisture,  alkali,  and  ale.  .ho 


The  purchase  by  Richard  J.  Zaiden,  president  of  the  I'itt-hurg 
School  of  Plastics,  of  three  large  buildings  to  house  a  "Plastic 
City,"  has  been  reported.  Interior  of  one  of  the  buildings  ha 
been  made  into  class  rooms  for  the  school,  and  all  remainiq 
space  is  to  be  occupied  by  tenants  engaged  in  the  plastics  a 
allied  industries,  one  building  having  been  remodeled  for  a  com 
plete  plastics  fabrication  plant 


Two  plastics  substitutes  for  metal,  adopted  by  the  Veteran 
Administration  during  the  war,  have  proved  their  worth  to  MIC 
extent  that  their  u>e  will  be  continued  in  the  Veteran-.  Admintl 
tration   hospital   construction   program,   according   to  am 
ment. 

Armor  plates,  push  plater.,  and  kick  plates  for  swinging  dooj 
will  accordingly  be  of  h'urmica.  while  door  knobs  are  to  Ix-  mad 
of  cellulose  acetate  butyrate. 


Manufacturing  space  has  been  leased  in  Middlcbury,  Vt 
by  Polymers,  Inc.,  a  new  plastics  company  which  plans  produc 
tion  of  extruded  bristles,  for  hairbrushes,  as  its  initial  liiH 
Principals  of  the  company  are  Alfred  H.  Drewes  and  dillioi 
Shaw,  both  formerly  of  Yonkers,  N.  Y. 


Said  to  produce  a  lustrous  hammered  effect  in  a  single  spn 
r.i.it   applji '.ttioii,  a  new  coating   has  IK-CM  announced  by   Maas 
\\  'aM-triii  Co..  Newark.  N    J.      Marketed  as    \l,>tlft,mf.  the  nei 
product  is  available  .1-  .111  air-dry  or  baking  finish  and  may 
usi-d  on  metal  equipment,  molded  plastics  products,  and  on  woo 
when   a   metal-like   hammered    finish    is   desired.      According 
the    manufacturer.     Mulli-lun?     tends     to     hide     weld    dimple 
scratches,    anil    other    minor    detects,    and    has    Ix-en    e-- 
tin  tided  where  low  cost  finishing  is  required. 


Announcement  has  been  made  by  John  S.  Itarnes  Cor 
Rockford,  III.,  that  (leoige  M  IV.ir-e  to,  965  Broad  St.,  Nei 
ark,  N.  J.,  has  been  appointed  sales  representative  for  the  cort 


PLASTICS 


SUTKMHKK  nu 


ny's  hydraulic  equipment  in  the  metropolitan  New  York  and 
;wark  territory.  It  is  also  announced  that  Ernest  C.  Hawkins, 
-merly  manager  of  the  Barnes  branch  sales  office  in  Newark, 
now  in  charge  of  the  newly-opened  Chicago  office  at  135  S.  La 
.lie  St. 


Beginning  of  construction  of  a  new,  $1.000.000  chemical 
ant  near  Portland,  Ore.,  has  been  announced  by  Pennsylvania 
lit  Mfg.  Co.  of  Washington.  The  new  plant,  which  company 
kials  expect  will  be  in  operation  about  the  1st  of  June  1947, 
to  produce  liquid  chlorine,  liquid  caustic  soda,  sodium  chlorate, 
itassium  chlorate  and  sodium  hypochlorite. 


Plans  for  expansion  of  the  machinery  manufacturing  opera- 
Mis  and  research  activity  of  Industrial  Rayon  Corp.,  Cleveland, 
»ve  recently  been  disclosed  with  the  announcement  that  the 
>mpany  has  arranged  to  lease  43,000  additional  square  feet  of 
Dor  space  for  manufacture  of  machinery  and  for  mechanical 
search  and  development  work. 


Manufacture  and  sales  of  the  mechanical  power  transmis- 
on  department  of  Ideal  Industries  (formerly  Ideal  Commutator 
resser  Co.),  Sycamore,  111.,  have  been  acquired  in  entirety  by 
ovejoy  Flexible  Coupling  Co.,  Chicago,  according  to  announce- 
ent  recently  made. 


Notice  has  been  received  of  the  resignation  of  Morton 
atil  Schapp  from  the  post  of  assistant  treasurer  of  Pepperell 

fg.  Co.  to  organize  a  new  corporation  which  will  merchandise 
nd  distribute  a  group  of  consumer  products  of  B.  F.  Goodrich 
o.'s  Koroseal,  on  the  west  coast.  The  announcement  adds  that 
eadquarters  of  the  new  organization  are  to  be  in  Los  Angeles, 

ith  offices  in  San  Francisco  and  in  Seattle. 


The  first  complete  college  course  on  the  topic  of  plastics 
>r  retailers  is,  according  to  announcement,  to  be  initiated  on 
eptember  30  by  the  New  York  University  School  of  Retailing 

nd  the  Society  of  the  Plastics  Industry,  Inc.  The  fifteen- 
•cture  course,  conducted  by  selected  experts  on  plastics,  will  be 
fered  at  the  Washington  Square  Center  of  the  University,  on 
ionday  evenings.  It  is  further  announced  that  registration  will 

>e  by  invitation  only,  due  to  the  fact  that  widespread  interest  in 
le  course  will  make  close  limitation  necessary. 


Announced  as  an  outgrowth  of  the  successful  partnership 
f  Edmond  J.  Spence,  industrial  designer,  and  Arthur  Rigolo, 
irchitect  and  industrial  designer,  the  firm  of  Spence- Rigolo,  Inc., 
as  recently  been  formed,  with  offices  at  677  Fifth  Ave.,  N.  Y. 

Expansion  of  its  Vyncote  division,  to  meet  demand  for  its 
:ries  of  vinyl  plastics  coatings  in  the  metal  products  industry, 
as  been  reported  by  the  Watson-Standard  Co.,  Pittsburgh 
'yncotc  "prescription  coatings,"  compounded  to  individual  re- 
uirements,  are  said  to  resist  water,  grease,  oil,  chemicals,  heat, 
etc.,  and  to  be  adaptable  to  any  baking  cycle,  forming  a  surface 
1m  that  retains  the  properties  of  solid  plastics. 


Formation  of  the  new  industrial  chemical  consulting  firm 
E  Burrell  &  Neidig,  with  offices  at  115  Broadway,  New  York 
lity,  has  been  announced  by  its  principals,  Harry  Burrell  and 
I.  P.  Neidig. 

Consultation  services  on  formaldehyde  and  its  uses,  plastics 
and  their  raw  materials,  protective  coatings,  sales  development 
•ork  on  new  products,  research  administration  and  market 
turveys  for  trie  chemical  and  allied  fields,  are  planned. 


A  newly  developed  display  stand  built  sectionally  of  acrylic 
ods  for  supports  and  flat  stock  for  shelves  is  being  fabricated 
y  Monarch  Plastics,  Inc.     The  shelves  of  this  stand  are  made 
n  various  sizes,  in  full  circle,  half  circle,  and  quarter  circle 
hapes,  and  are  mounted  on  the  rods  by  means  of  steel  screws 
and  mating  taps  directly  in  the  rods.  .  This  arrangement  pro- 
vides opportunity  for  a  variety  of  merchandising  display  effects. 
Clear   acrylic  has   been  the   medium   used   for   these   sectional 
stands,  and  it  is  expected  that  black  and  ivory  acrylic  will  also 
soon  be  utilized  for  this  purpose. 


GRflVS  HflRBOR 


A  BACKLOG  OF  20  BILLION  FEET 
OF  "PLASTIC  TYPE"  TIMBER 


LOW-COST  TRANSPORTATION 
BY  AIR  -  TRUCK  -  RAIL  -  WATER 


I A  SURPLUS  OF  EFFICIENT  LABOR 
CHEAP  ELECTRIC  POWER 


Here  is  the  ideal  location  for  your 
wood  plastics  operation!  An  abun- 
dance of  "plastic  type"  timber  and 
mill  waste  for  long  range  planning 
. . .  PLUS  a  surplus  of  skilled  efficient 
labor. 

Ideal  industrial  sites  are  available 
now!  Well-financed  civic  organiza- 
tions such  as  Grays  Harbor  Indus- 
tries, Inc.,  are  eager  to  cooperate 
with  outside  capital  and  manage- 
ment. Write  for  specific  information, 
or  if  you  prefer,  a  personal  represent- 
ative will  call  on  you. 


GRflVS  HflRBOR 

WASHINGTON 

Sponsored  By 

GRAYS  HARBOR  INDUSTRIES,  INC. 

ABERDEEN,  WASHINGTON 


SEPTEMBER  1946 


PLASTiCS 


89 


SAVE  85%  ON  NEW 
WAR  SURPLUS 

DOUBLE-ACTING 

HYDRAULIC 
CYLINDERS 

46  Types,  Shapes,  Thrusts 
20,000  Available  For 

Immediate  Delivery 

/""/  Labor  Saving  Adaptations  for 

pulling,  pushing,  pressing  \-  [>las- 

tic  forming  operations 

Fln«it  preciiion  workmanship.  Aircraft  alloy  of  aluminum  and 
chrome  §t»el,  guaranteeing  trouble-free  operation.  Liquid 
and  'or  air  operation,  developing  terrific  power.  WRITE  FOI 
CATALOG. 

100,000  Ibs.  New 

PLEXIGLAS  &   LUCITE 

Available  at 

Tremendous  Savings 

Various  Sises,  Gauges 
PALLEY  SUPPLY  COMPANY 

IKC.-P86. 6321  San  Fernando  Road,  Glendale  1 ,  Calif. 

Citrus  34847  CUapman  52969 

WE  BUY  AND  SELL  SURPLUS  STOCK 


PL AST IX 


A   NEW   PENCIL  for  a   NEW   INDUSTRY 

Ordinary  pencils  won't  mark  .  .  .  ink  runs  and 
labels  fall  off  the  average  smooth,  glossy  plastic 
surface.  Blaisdelt  I'l.ASTIX  Pencils  were  modi 
for  the  purpose.  Their  marks  are  brilliant,  legible, 
waterproof  and  permanent,  yet  easy  to  remove 
with  a  damp  cloth.  Try  one  and  prove  it  yourself. 

Mod*  in  7   colott: 

1064. T  Whit.  1068-T  »lu.  1070  T  Yellow 

1045. T  Crhioon  R.d  1069-T  R.d  1071  T  Gr..n 

1073- T  Mock 
Order  from  vovr  d*o'«r  or  —     •fc-.  ,j .  *    r*t.  OS 

MM!  tkit  n*t>o>,/or  FREE  SAMPLE 

jQ/aisdetf  PENCIL  COMPANY 

141  Berkley  St.,  Philadelphia  44,  Pa.,  Depl.  PL-2 
Send  me  sample  of  No. 


Dr.  Royal  K.  Abbott,  of  General  Electric  Co.'s  Pittsfiejl 
Laboratory  division,  recently  left  for  Rio  de  Janeiro,  UraziL 
where  lie  will  be  laboratory  director  for  General  Electric  S  \' 
In  his  new  post,  Dr.  Abbott  will  continue  the  work  in  the  field 
of  synthetic  organic  dielectrics,  in  which  he  was  engaged  while  at 
Pittsfield. 

*        *        * 

Recent  personnel  appointments  in  the  Lumite  Division  Chi- 
copee  Mfg.  Corp,  include  those  of  J.  W.  Veeder  to  the  position 
of  advertising  and  sales  promotion  manager;  and  Harry  H. 
Purvii,  to  vice  president  and  genera!  manager  of  the  division1! 
new  plant  at  Cornelia,  Ga.;  Alfred  Russell  becomes  eastern 
U.  S.  representative  for  certain  Lumite  fabrics ;  and  Donald  M. 
Odell  has  been  named  assistant  to  the  sales  manager  of  the 
division,  succeeding  Harold  Brown,  who  has  been  tran- 
to  Chicago. 


J.  W.  Ve«der 


H.  H.  Purvia 


Harry  A.  Johnson,  recently  returned  from  Army  service  as 
a  Colonel  in  the  Coast  Artillery  Corps,  has  rejoined  Westing, 
house  Electric  Corp.  in  the  capacity  of  Micarta  and  insulation 
specialist,  with  headquarters  in  San  Francisco. 

*  *        * 

Recent  engineering  personnel  changes  at  Cincinnati  Milling  tt 
Grinding  Machines,  Inc.,  include  the  following :  John  E.  Lynch, 
manager  of  the  company's  Cincinnati  office  for  14  yrs.,  to  man- 
agership of  the  New  York  office;  Carl  M.  Beach  to  manager 
of  the  Detroit  office;  E.  F.  Render  from  Syracuse  to  Detroit; 
and  W.  Kent  Mathias  to  the  Syracuse  office. 

*  *        * 

The  retirement  of  A.  C.  Funk,  after  35  years  of  service  «ith 
the  National  Adhesives  Division  of  National  Starch  Product* 
and  its  predecessor  companies,  has  been  announced. 

*  *        * 

Arthur  J.  Frankel,  formerly  with  Irvington  Vamish  &  In- 
sulating Co.,  has  been  appointed  director  of  research  of  Kland 
Charnas  Co.,  Inc.,  plastics  fabricators,  Yonkers,  N.  Y.,  where, 
it  is  announced,  he  will  co-ordinate  laboratory  testing  and  re- 
search with  the  work  of  the  Plastics  Home  Institute. 

('apt.  Sidney  Aril,  lately  returned  from  Army  service,  has 
joined  the  Bland  Charnas  organization  as  sales  manager  of  the 
industrial  division. 

•  •    » 

W.  H.  Tonn,  Jr.,  has  announced  his  resignation  from  the 
^  itT  of  the  Massachusetts  Institute  of  Technology,  Plastics  Ma- 
terials Manufacturers  Association  project,  to  become  a* 
professor  of  chemical  engineering  at  the  University  ot  Okla- 
homa. He  plans  to  continue  his  active  research  and  consulting 
work  on  plastics,  resins,  and  adhesive*. 

•  •    * 

W.  F.  Leicester,  president  of  the  Borden  company's  Casein 
Co.  of  America  division,  has  been  elected  a  vice  president  <>f  the 
Borden  Co.,  and  will  have  executive  supervision  of  adhesive*,] 
including  casein,  and  related  activities. 

*  •        • 

David  Maxwell  has  joined  the  design  and  development  or- 
ganization of  Rertell,  Inc..  N.  Y.,  as  director  of  product  develop- 


90 


SKITKMRKR   1946 


nent,  and  company  associate.    He  was  formerly  with  J.  Gordon 
Lippincott  Co.,  in  a  similar  capacity. 

*  *        * 

Richard  T.  Nalle,  executive  vice  president  of  the  Midvale 
Co..  Philadelphia,  was  recently  elected  to  the  board  of  directors 
rf  Pennsylvania  Salt  Mfg.  Co. 

*  *        * 

Donald  A.  Potter  has  recently  been  appointed  research  and 
development  engineer  for  Universal  Castings  Corp.,  Chicago. 

*  *        * 

R.  W.  Gillmore  is  in  charge  of  the  new  branch  office  which 
has  been  opened  in  Evansville,  Ind.,  by  Allis-Chalmers  Mfg.  Co., 
Milwaukee. 

Warren  J.  Holmes  has  been  named  export  representative  in 
the  Philippine  Islands  for  the  company. 

*  *        » 

Dr.  Emil  Ott,  director  of  research,  Hercules  Powder  Co., 
and  Eero  Erkko,  his  technical  assistant,  are  making  a  two- 
months'  tour  of  Europe,  visiting  chemical  plants  in  various 
countries,  principally  in  the  interests  of  research  in  the  field  of 
cellulose  chemistry. 

William  L.  Cahall,  recently  appointed  sales  manager  of  the 
company's  export  department,  is  making  an  eight-months'  busi- 
ness trip  during  which  he  will  visit  points  in  the  Near  East,  Far 

East,  and  southern  Africa. 

*  *        * 

Reed-Prentice  Corp.,  Worcester,  Mass..  has  announced  the 
appointment  of  John  G.  Thompson  as  sales  and  service  repre- 
sentative for  the  company's  injection  molding  and  die  casting 
machines  in  California  and  Nevada. 

*  *        * 

Returned  from  three  and  one-half  years'  service  in  the  U.  S. 
Navy.  Lt.  Comdr.  William  R.  Bowen  has  returned  to  Parrel- 
Birmingham  Co.,  Inc.,  to  become  manager  of  the  company's 
branch  sales  office  in  Akron,  O.  He  succeeds  Harry  D.  Tem- 
poral, who  has  been  made  manager  of  the  Chicago  office. 

*  *        * 

S.  Leon  Kaye,  formerly  chief  engineer  and  production  man- 
ager for  Universal  Plastics  Corp.,  has  announced  his  intention  of 
going  into  the  injection  molding  business  for  himself. 

*  *        * 

Goodyear  Tire  &  Rubber  Co.  has  announced  personnel  appoint- 
ments as  follows :  Dr.  Harold  R.  Mighton  and  Dr.  Thomas 
G.  Fox,  Jr.,  have  joined  the  company's  research  laboratory  to 
aid  in  a  program  of  expanded  activity  in  the  field  of  fundamental 
research  in  synthetic  rubber  and  plastics. 

In  the  company's  Pliofilm  sales  department,  J.  C.  E.  Williams 
has  been  named  manager  of  converter  sales,  and  E.  J.  Dunlavy, 
Jr.,  has  been  assigned  to  the  fabricating  field. 

Retired  with  the  rank  of  colonel,  after  four  years'  service  in 
the  U.  S.  Army  Air  Forces.  Max  F.  Moyer  has  returned  to 
Goodyear  organization  as  assistant  manager,  flooring  and  build- 
ers' supply  department. 

*  *        * 

American  Foundry  Equipment  Co.  announces  appointment  of 
sales  representatives  George  C.  Tolton  for  the  Northwestern 
states,  with  office  in  Seattle;  Anthony  Stimmler  in  the  com- 
pany's new  Minneapolis  sales  office;  Mitchell  P.  Christensen. 
for  the  newly  created  Denver  territory. 

*  *        * 

An  office  at  522  Fifth  Ave.,  New  York  City,  has  recently  been 
opened  by  Gerry  Powell,  typographic  director  of  American 
Type  Founders,  Elizabeth,  N.  J.,  for  the  purpose  of  extending 
his  activities  in  packaging  and  product  design.  He  will  continue 
his  post  at  American  Type  Founders,  according  to  announce- 
ment. 

*     *     * 

Dr.  C.  Lalor  Burdick,  of  the  DuPont  Co.,  has  returned  from 
a  year's  duties  in  Mexico  City,  and  is  to  head  a  special  "High 
Polymer  Committee"  to  study  and  coordinate  the  company's  re- 
search and  manufacturing  activities  in  materials  such  as  nylon, 
plastics  and  similar  polymeric  compounds. 

*  *        * 

L.  W.  McDowell,  Aurora,  111.,  has  advised  of  his  appointment 
as  middle-western  representative  for  Shortwave  Plastic  Forming 
Co.,  Burbank,  Calif.,  maker  of  the  high-frequency  Woodwelder. 


•  Certain  plastics  withstand  heat 
better  than  others.  Some  are  particu- 
larly adapted  for  jobs  that  must  with- 
stand wear.  Others  are  best  for  ma- 
chining and  threading.  •  The  secret 
V  of  success  in  plastics  is  in  knowing 

^         the  right  plastic  to  use  for  the  job  at 
\         hand.  •  Ask  us  to  help  you  see  what 
\       plastics  can  do  in  your  business. 

- ^X       •  Just  send  photo,  sample  or  specifi- 

>k    cations,  and  we'll  tell  you  quickly  if 
\  it  can  be  made  in  moulded  plastics 

THE  MAGNETIC  PLASTICS  CO. 

1900  EUCLID   BUILDING      •      CLEVELAND   15,   OHIO 


^ex-tile 

Woven  of  SARAN  BY  NATIONAL,  new  col- 
orful fabrics  are  today  being  created  in  many 
interesting  textures  and  patterns,  for  a  mul- 
titude of  uses. 

These  SARAN  fabrics  resist  scuffing  and 
abrasion,  won't  absorb  dirt,  grease  and  most 
chemicals.  SARAN  is  demonstrating  its  re- 
markable properties  today  in  upholstery  fab- 
rics, auto  seating,  handbags,  shoes  and  many 
other  superior  products. 

•   Our  technical  facilities  are  available  for  the 
study  of  your  product.    Write  today. 


ODENTON  •  MARYLAND 


SEPTEMBER  1946 


PLASTICS 


91 


Wi 

I  V  {i 


irror 


w. 


/ 

h 


ilize  in  the  na.ro. 


'e  Specialize  in 
chromium  pfatina  of  pla&tic 
moulds  and  dies  to  a 

/•       / 
finish. 


mirror 


CHROME  SERVICE 


Sove  It  with  Chromium 

9350  GRINNELL  AVE.      •      DETROIT  13,  MICH. 
Plaza  3164 

1926          Our  20th  Year  oi  Dependable  Service  1946 


ATTENTION- RECORD  MANUFACTURERS! 

N.w  INDUSCO  75  Ton  and  100  Ton  S.ml-Automatic  Phonograph  R.cord 
Praising  Uniti.  Comprising  Prastas,  Pumps,  Motors,  Hydraulic,  Staam 
and  Watar  Valvas,  Automatic  Tlmars  and  All  Accassorias.  Tha  75  Ton 
Units  for  10"  and  12'  Shallac  and  10"  Vinylita  Racords,— (ha  100  Ton 
Units  for  12"  Vmylita  R.cordi.  Prompt  D.liv.ri.i. 

N.w  INDUSCO  IS7  Ton  and  400  Ton  Mobbing  Prassas  12"  Daylight, 
Hardanad  Staal  Anvils,  Each  Complata  with  Eithar  Hand  or  Powar 
Drlvan  Pump  with  Nacassary  Piping  and  Accastorlas. 

Naw  INDUSCO  75  Ton,  100  Ton.  ITS  Ton  and  225 
Ton  Molding  Prassas.  Platan  Silas  from  12"  «  12" 
up  to  30"  i  24".  Daylight  Opanings  to  Suit. 

Various  Silas  and   Capacitias  of   Usad.   Suaran- 
taad,  and  Naw  Prassas,  Pumps,  Accumulators. 
Prompt  Dalivarias.     Full  Datails  on   Raquast. 

Write.   Wire.  Phoft. 

INDUSTRIAL  EQUIPMENT  COMPANY 

171  (rood  Straat  Nawark  2.  New  Jaruy 


RICHARD  C.  KLEINBERGER 

Licensed   Professional  Engineer 

Consultant  on 

ELECTRONIC  HEATING  APPLICATIONS 

20  CUSHMAN  ROAD 
WHITI  PLAINS.  N.  Y. 


FOR  SALE- 


N."   t   Usad   Hydraulic   Equipment.     Consultant,   cnqmaarinq 
and    Rapan    Sarvica       Sand    us   your    inquirias 

AARON   MACHINERY  CO. 

41  Cr.tbr  St..  N.    t.  C.    12  T.I.   C..o.   »  0421 


Compression  Mold  Design 

(Continued  from  page  72  > 


flash  (Fig.  lOb)  the  thickness  of  which  can  be  controlled. 
However,  the  mold  still  has  the  land  or  flash  ridge  which 
traps  material,  so  variation  of  dimensions  across  flash  is 
still  a  problem  in  this  type.  The  small  telescoping  portion 
i-  -ul>ject  to  wear  and  scoring  but  less  than  with  the  landed 
positive. 

Another  and  seldom  used  type  is  the  sub-cavity  mold 
(Fig.  11).  This  mold  has  the  advantage  of  a  single  loading 
area  for  several  cavities,  thus  cutting  down  on  mold  loading 
time  and  making  a  cheaper  die  than  any  other  self-contained 
type  with  more  than  one  cavity.  However,  its  use  often  re- 
sults in  a  thick  flash  and  castings  of  poor  density,  and  it  is 
-i-ldom  used  for  these  reasons. 

Influence  of  Material  Grade 

The  grade  of  material  to  be  run  in  the  mold  has  important 
bearing  on  the  type  of  mold  selected. 

The  woodflour  filled  general  purpose  phenolics  can  IK'  run 
in  any  type  of  mold  in  most  designs.  They  pill  readily  and 
therefore  can  be  used  with  a  small  loading  space.  Here, 
selection  of  type  depends  on  the  relative  importance  of  die 
cost  vs.  material  cost,  which  is  dependent  on  anticipated 
production  and  on  the  quality  required  in  the  piece.  Castings 
from  a  flash  mold  will  be  dense  enough  for  the  great  ma- 
jority of  woodflour  jobs. 

Cotton  flock  or  medium  impact  phenolics  can  run  in  any 
tyi*-  except  the  flash,  and  in  many  designs  a  flash  mold  will 
be  acceptable.  Bulk  factor  is  a  little  higher  than  for  the 
preceding  group  and  pilling  not  as  good,  so  loading  space 
must  be  carefully  considered  before  adopting  a  flash  type 
design. 

High  Impact  Phenolics 

Rag  or  cord  filled  high  impact  phenolics  cannot  be  run 
satisfactorily  in  a  flash  or  sub-cavity  mold  because  the  flow 
characteristics  of  these  compounds  are  not  good  and  the 
Hash  is  extremely  tough  and  difficult  to  clean  if  allowed  to 
become  thick.  The  high  bulk  factor  and  poor  pilling  of  this 
material  requires  a  mold  with  a  large  loading  space.  R< 
of  this  and  the  tough  flash  a  landed  positive  mold  is  usually 
selected  if  these  materials  are  to  be  compression  molded. 
Transfer  molding  is  by  far  the  better  method  for  handling 
this  type  of  material. 

The  mineral  filled  heat  resistant  phenolics  mold  similarly 
to  the  woodflour  filled  except  for  the  long  fiber  asbestos 


/OB 
-  fostnvr  MOLD  H/rrmffncAi. 


92 


f»  I.  \  M  T 1 1  * 


SKI'TKMHKK    lillfi 


CAVITY 


compounds,  which  should  be  treated  like  the  high-impact 
jgroup. 

Urea  and  alpha  cellulose  melamine  offer  another  prob- 
lem. They  mold  differently  from  the  phenolics,  and  require 
more  care  and  consideration  in  selecting  the  type  of  mold. 
Here  complete  sealing  of  the  cavity  is  important  on  many 
shapes ;  therefore  a  loose  fitting  positive  or  landed  positive 
would  not  do.  The  semi-positive  mold  is  best  for  molding 
the  ureas,  but  some  shapes  can  be  run  in  flash  molds.  The 
recommendations  of  the  manufacturers  of  these  materials 
concerning  type  of  mold  are  clearly  outlined  in  their  litera- 
ture, and  these  should  be  obtained  and  carefully  studied 
before  designing  molds  for  these  materials. 

There  are  special  features  which  are  incorporated  in 
molds,  to  take  care  of  threads,  undercuts,  bosses,  etc.  These 
will  be  covered  in  detail  in  Part  2  after  the  standard  design 
problems  have  been  discussed.  (TO  BE  CONTINUED) 


r 


Plastics  "Franks" 

(Continued  from  page  56) 


Today,  these  casings  are  the  most  popular  in  the  world  and 
form  the  backbone,  so  to  speak,  of  the  sausage  industry.  Ap- 
proximately 60%  of  the  tens  of  millions  of  frankfurters 
consumed  by  Americans  every  year,  as  well  as  a  huge  per- 
centage of  all  other  sausages  produced,  are  made  with  cellu- 
lose casings. 

Essential  Properties 

The  essential  properties  of  a  satisfactory  sausage  casing 
are:  Strength — to  withstand  the  handling,  stretching  and 
pressure  developed  in  processing;  penetrability  by  smoke — 
to  permit  the  development  of  flavor,  cure  and  color ;  non- 

toxicity;  stability — to  withstand  the  water,  heat,  meat  juices, 

;and  curing  agents  used  in  the  production  of  sausage ;  and 
flexibility  and  close  fit  to  the  surface  of  the  meat.  In  addi- 
tion, other  desirable  characteristics  are  uniformity  of  each 

[size,  and  a  wide  range  of  sizes ;  low  weight,  particularly  in 
relation  to  contents;  ability  to  take  printing;  and  conven- 

tience  in  handling  without  danger  of  spoilage  or  deteriora- 
tion. 

Regenerated  cellulose  sausage  casings,  alone,  satisfy  those 

Requirements.  The  casings  are  extremely  strong,  for  the 
raw  materials  and  processes  employed  in  their  manufacture 

Zare  selected  to  insure  maximum  strength.  (A  Visking  cas- 
ing, for  example,  will  hold  200  times  its  own  weight  in 
sausage  meat  and  will  stretch  as  much  as  60%  in  stuffing.) 
Smoke  readily  penetrates  these  casings,  and  besides,  cellu- 
lose is  inert,  non-toxic;  flexible  and  elastic.  It  is  not  af- 
fected by  boiling  water  or  smokehouse  conditions  of  tem- 
perature and  moisture,  and  can  be  readily  printed  upon  so 


NEW  WATER-SOLUBLE 
DYES  FOR  CLEAR  PLASTICS 


completely  true  shade*  may  be  obtained  Thie 
method  can  be  mod  by  he  fabricator  or 
molder  before  or  after  proc  ssing.  Inexpen- 
sive— simple — uniformity  of  olor  throughout. 
Heat  solution:  Simply  dip — rinse  with  water 
and  that's  all  —  No  expens  ve  equipment  or 
high  priced  chemicals  to  b  y._ 

Among  the  other  excell  nt  products  from 
our  laboratories  are  Annealing  Compound 
(Acrylic  Cement).  Laminating  Dyes  (Col 
ored  Cement).  New  Sensational  "QAM 
CO"  Buffing  Comfwvmd— will  n«»  fc".n 


Phone  FEderal  1109 


GREAT  AMERICAN 
COLOR   COMPANY 

25 12  WEST  NINTH  STREET 


LOS  ANGELES,  CALIF. 


Canadian  Kept  Colors  &  Finishes  Co.,  222   Front  Street,  East  Toronto,  Ontario 
New  York  Rep;  Plastics  Dye  &  Supply  Co..  Ocean  Gate,  New  Jer.ay 

We  a/so  Manufacture  a  complete  fine  oi  Cold  dip  dyes. 


SEPTEMBER  1946 


I'l.ASTlCS 


93 


WANTED 

PLANT  SUPERINTENDENT 

Plastic  Injection  Molding 

Manhattan 

Must  be  experienced  and  able  to  handle 
men.  Furnish  detailed  information  regard- 
ing experience,  ability  and  salary  expected. 
Box  No.  102,  c/o  PLASTICS,  185  N. 
Wabash  Ave.,  Chicago  1,  Illinois. 


Canadian    Sales   Organization 

specialized  in  Plastic  items,  would  like  to  act 
as  distributors  or  representatives  of  Plastics 
manufacturers  for  Canada.  Box  100,  c/o 
PLASTICS,  185  N.  Wabash  Ave.,  Chicago,  111. 


FOR  SALE 

3  Triplex  Hydraulic  Pumps  with  7Vt  h.p.  Gen- 
eral Electric  Motors  (220-440  v.).    Capacity  2t>UU 
pounds.    Delivery  15  gal.  low  pressure,  5  gal. 
high  pressure.    Write,  call  or  wire. 

GEORGE  STEINER  COMPANY 
1220  W.  Lake  Street  Chicago,  Illinois 

Haymarlcet  6027 


WANTED.!  —  GENERAL  WORKS  MANAGER 

for  Modern  Ploitic   Molding  Plant 

RARE  Opportunity  for  an  aipar/ancad  man.  who  can  prova  his  ability 
to  handla  such  a  job.  Ha  mutt  hava  aitansiva  aiparianca  in  practical 
mold  making,  and  mutt  ba  wall-varied  in  tha  latast  plastic  molding 
production  and  finishing  tachniquat.  Writa  ut  fully. 

Addrtu  t.  A.  Patartan,  Preildanf 

CHICAGO  DIE  MOLD  CORPORATION 

4001   Wriqhtwood  Ave..  Chicago  39,   III. 


AUSTIN  TOOL  &  MFG.  CO. 

1859  E.  63rd  STREET       -:-       CLEVELAND  3,  OHIO 

EXpress  1000 
OISIONUS  PLASTIC  MOLDS  BUILDUS 

Quotation*  Wltfcin  44  H«*n 


TECHNICAL 
*  SCIENTIFIC 
CATALOG 
FREE 

tide   &   Technologi- 
cal-  II     I:    Kl.-i-k  9  OJM> 

M...IITH    oi-KiiMii-     Finishes  —  R.    H. 

\V:illl|il«T       l\Mt 

riimilr   M..I.HIIIT  &  Plant  Manatje- 

niflit  —  I)     A.     Di-url*.     .                                   :<  TUi 

Special  nervlce*  and  dlnrounti<  ftlvcn  to  Industrial  firm*. 
ENGINEERS'    BOOK  [SjE  R  V  I  C  E  , 

It  WEST  Mtk  IT.               ••am  1002;              NEW  TORK  CITT  11 

PLASTIC  MACHINERY 

Caff  CA-6  2500 


MOVING 


.RASILOVSKY 


TriKkmon  end  Mottar  Riggan 


'RUCKING,  INC. 
1 39  Grand  St..  N.  V.  C. 


as  to  permit  decoration,  identification  and  the  listing  of  in- 
gredients which  are  now  required  by  State  and  Federal 
regulations. 

Frankfurters  constitute  about  one-third  of  all  sausage 
iu-iii;,  manufactured.  Because  of  the  huge  demand  for  these 
products,  the  first  cellulose  casings  made  were  for  this  use 
I  'iskint/  frankfurter  casings  are  made  up  in  lengths  of  32  ft. 
These  are  shirred  and  compressed,  accordion-wise,  to  a 
length  of  7",  ready  to  be  slipped  over  the  stuffing  horn  at 
the  packing  plant  without  additional  preparation.  The 
packer  rir  >au>agc  maker  .-.tuffs  meat  into  these  lengths  of 
r;i-ini;>,  and  the  filled  casings  are  then  linked  in  equal 
lengths  and  Miioki-d,  after  which  they  are  cooked.  \Yhen 
thi>  has  been  done,  the  cellulose  casings  are  removed.  The 
result  is  a  frankfurter  that  is  uniform  and  exact  in  M/C. 
There  are  no  skins  and  no  coverings  of  any  kind  on  these 
sausages  when  the  customer  lmy>  them.  This  technique 
offers  a  number  of  advantages  over  animal-casing  frank- 
furters; for  example,  skinless  frankfurters  are  accepted  a^ 
being  more  easily  digested  than  tho>e  with  ca>inn>.  and  they 
possess  the  added  quality  of  not  splitting  OJH-II  while  Ix-int; 
boiled. 

Uniform  Size 

The  uniformity  in  length  and  width  of  these  frankfurter 
casings,  and  their  freedom  from  defects,  assure  maximum 
efficiency  of  labor  and  equipment  in  handling  and  pn 
ing,  and  they  are  more  economical  to  use  than  animal  cas- 
ings. Occupying  small  space,  light  in  weight,  and  packed 
in  moisture  proof  boxes,  they  can  conveniently  l>e  stored  for 
indefinite  periods  without  concern  for  refrigeration,  condi- 
tioning, or  spoilage,  and  the  ease  with  which  they  can  be 
transported  constitute*  an  additional  factor  to  recommend 
them. 

Cellulose  frankfurter  casings  are  made  in  nine  standard 
sizes  ranging  from  2%2"  to  *%s"  dry  diameter,  the 
elasticity  of  the  regenerated  cellulose  making  it 
possible  for  them  to  be  stretched  about  l?'r  when 
stuffed.  They  have  eliminated  the  necessity  for  imports  of 
casings  and  have  stabilized  their  price.  And  because  of 
their  replacement  of  sheep  intestine  casing*,  adequate  sup- 
plies of  the  animal  product  have  now  become  available  to 
fill  a  highly  important  requirement  in  the  making  of  sutures 
for  surgical  work. 

Opaque  Cellulose  Casings 

Visking  casings  are  also  used  for  hundreds  ot  different 
kinds  of  large  sausage.  Cervelat,  bologna,  Polish  sausage, 
thuringer,  salami — these  and  a  number  of  others  are  stuffed 
in  plastics  casings,  their  most  common  sizes  ranging  all  the 
way  up  to  5l/t"  dry  diameter.  The  larger  casings  are  ob- 
tainable in  either  of  two  type*:  standard  stretch  and  high 
stretch.  In  stuffing,  the  standard  stretch  casings  may  be 
expanded  33%%  above  their  original  diameter  while  high 
stretch  casings  may  be  expanded  as  much  as  50%  to  60%. 
The  customer's  choice  is  determined  by  hi*  requirements 
and  wishes  in  the  matter  of  capacity  of  the  i-a*ing.  ap|x-ar- 
ance  of  the  product,  and  uniformity  and  distortion  of 
printing 

Fibrous  Casings 

There  are  two  other  types  of  cellulose  c.i*mg*  which 
merit  a  few  words.  One  of  these — fibrous  casings — has 
been  especially  designed  to  withstand  the  most  severe  han- 
dling and  processing  conditions.  These  fibrous  casings  con- 
sist of  a  base  of  specially  prepared  cellulosic  fiber,  impreg- 
nated and  coated  with  regenerated  cellulose  of  the  same 
nature  as  the  material  constituting  other  cellulose  casings. 
They  are  made  on  special  and  highly  complex  machines,  and 
are  the  strongest  casings  known.  They  withstand  great 


94 


FLASTiCS 


SKI'TKMHKR   1946 


stuffing  pressure  and  high  smoking  and  cooking  tempera- 
tures which  often  produce  considerable  expansion  and  in- 
ternal pressure.  For  special  purposes  they  are  "prestuck" 
or  perforated  with  a  multitude  of  tiny  holes  which  permit 
the  enclosed  product  to  "breathe,"  and  eliminate  air  and 
jelly  pockets. 

Fibrous  casings  permit  smoke  penetration.  They  can  be 
preprinted  in  the  same  manner  as  other  cellulose  casings 
and,  because  they  do  not  stretch,  there  is  no  distortion  of 
printing  on  the  sausage  product.  They  are  obtainable  in 
any  length,  and  because  of  their  great  strength  are  fre- 
quently used  for  heavy  and  long  types  of  sausage.  These 
casings  come  in  a  half-dozen  different  colors,  the  color 
being  on  the  outside  of  the  casing  only,  so  that  it  does  not 
come  in  contact  with  the  fillings. 

Opaque  Cellulose  Casings 

Some  sausage  products,  particularly  those  that  are  finely 
ground,  such  as  liver  sausage,  braunschweiger  and  some  loaf 
items,  darken  when  exposed  to  light  and  thereby  become 
unappetizing  in  appearance,  and  unsalable.  For  such  sau- 
sages, opaque  cellulose  casings  are  made.  Available  in  the 
regular  and  fibrous  types,  the  opacity  is  produced  by  the 
incorporation  of  a  harmless  and  inert  pigmenting  material 
in  the  cellulose  solution  from  which  the  casings  are  made. 
Unlike  the  animal  casings  which  they  replace,  opaque  cas- 
ings possess  uniform  quality  in  diameter  as  well  as  in 
appearance. 

The  amazing  recent  progress  made  in  the  various  fields 
of  plastics  has  often  overshadowed  some  of  the  important 
advances  engendered  by  synthetics  for  many  years.  Cellu- 
lose sausage  casings  provide  an  excellent  example  of  such 
advance.  END 


I 


Patting  Agent 

{Continued  from  page  81 ) 


iiimnmiini »f 


The  jelly  is  not  available  in  ready-to-use  form,  though 
quince  seeds  are  inexpensive  and  easy  to  prepare.  Any  drug 
supply  house  carries  them  in  bulk  or  in  the  purified  form 
used  in  prescriptions,  but  the  ordinary  grade  is  all  that  is 
necessary. 

Put  a  pound  of  seeds  in  a  two-gallon  container  and  pour 
in  a  gallon  of  warm  water — not  hotter  than  100°  F.  Soak 
about  12  hr  and  the  seeds  will  swell,  filling  the  container. 
The  jelly  will  be  a  transparent  emulsion  about  the  thickness 
of  syrup. 

Two  strainings  are  needed  to  cleanse  it:  one  through 
cheese  cloth  to  cull  the  seeds,  the  other  through  a  piece  of 
rough  silk  to  remove  the  dirt.  This  will  give  sufficient 
purity  for  ordinary  purposes.  If  you  want  super-purity, 
you  can  draw  the  jelly  through  a  filter  paper  with  the  aid 
of  a  vacuum  pump. 

To  Preserve  Jelly 

Telly  in  this  form  will  spoil — and  quickly.  To  preserve 
it,  add  one-tenth  of  one  per  cent  of  formaldehyde — the  com- 
mercial variety  used  in  sterilizing  supplies  in  barber  shops 
and  beauty  salons.  No  other  precautions  are  necessary. 
The  solution  will  keep  indefinitely. 

Being  nearly  transparent,  the  jelly  will  blend  with  the 
color  of  the  mold.  If  you  prefer  a  colored  parting  agent, 
you  can  add  a  few  drops  of  any  water  soluble  dye,  enough 
to  give  a  tint.  The  dye  will  be  color  permanent  and  will 
not  stain  either  the  casting  or  the  mold. 

To  apply  the  jelly  to  a  mold,  brush  on  a  thin  coat  and 
allow  to  dry.  Use  of  lacquer  or  other  auxiliary  material 
to  aid  releasing  is  unnecessary.  By  itself  the  jelly  will  part 
the  mold  and  casting  every  time.  END  i 


complete 
plastic 
display 
fabrication 


This  gauze  pad  dispenser,  made 
for  one  of  the  leading  surgical 
supply  houses,  illustrates  one  of 
the  many  unusual  plastic  dis- 
play assignments  executed  by 
Printloid. 

Consult  with  our  design  staff 
now. 


DEPT.  P 
93  MERCER  STREET.  NEW  YORK  12.  N.  Y. 


T   h   <• 


P    I    a    i    f    I   < 


Built 


Specify  MICCROPLATE  Super-Finish  ...  the  finest  of 

KURD  [HRomium 

PIBTinC  FOR  PLHSTK 
mOLDS  HnD  DIE! 


MICCROPLATE  Super-Finish  ii  a  new  improved  hard 
chromium  plating  technique  developed  by  specialists  of 
the  Michigan  Chrome  and  Chemical  Company  ...  It 
produces  high-luster  castings  —  eliminates  repolilhing, 
corrosion,  pitting  and  discoloration  —  prevents  material 
adhesion,  facilitates  material  flow,  reduces  wear  and 
preserves  mold  finish. 

Send  your  molds  and  dies  for  AMCCROPIATE  Super- 
Finish.  AH  work  guaranteed.  24  HOUR  SERVICE! 


Developed  and  Manufactured  by  rxperienced  Platen 


MICHIGAN    CHROME    and 
CHEMICAL    COMPANY 

6342  East  Jefferson  Avenue 
Detroit  7,  Michigan 


SEPTEMBER  1946 


PLASTiCS 


95 


•  •  .  •  • 


YOUR  ASSETS  and  CAPITAL  STOCK  are 
WORTH  MORE  NOW 
We  are  willing  to 


PAY     YOU 

CASH 


For  Your 

•INDUSTRIAL      PLANTS 
•MFG.    DIVISIONS     or    UNITS 

We  are   principals  acting  In  our  own   behalf.     All 
transactions    held    in    strictest    confidence. 

Personnel  retained  wherever  possible. 
ADDRESS:  Box  1241.  147  W.  42  St..  New  York  18.  N.  Y. 


PRODUCTION  ENGINEER  WANTED 

.  .  .  by  substantial,  well-established  manufacturer  in  the 
thermo-plastics  field.  A  modern  plant,  wide  range  of  equip- 
ment. 

Offers  unusual  opportunity  for  a  man  with  ability  to  estab- 
lish modern  methods  and  secure  maximum  production.  Engi- 
neering degree  and  several  yaari  practical  experience  in 
quantity  production  of  injection  molded  thermo-plastics  is 
required.  TharmoieHing  experience  desirable. 
Age— 30  to  45  preferred. 

Address  application  to  Box  101.  c  o  PLASTICS, 
185  N.  Wabash  Ave  .  Chicago.  III. 


ROUTER  BITS— FORM  CUTTERS  and 
MACHINES  lor  HIGH  SPEED  CON- 
TOUR and  STRAIGHT  CUTTING  PLASTICS 

Stud  for  Cflalof  No.  4) 

EKSTROM,  CARLSON  &  CO. 

1410  Railroad  AT*.  ROCXFORD.  ILL. 


— "KRIEGR-O-DIP"— 

HOT  AND  COLD 
Dyes  lor  All  Types  ol  Plastics 

Manufactured  By 

KRIEGER   COLOR   &  CHEMICAL  CO. 

Member  ol  the  S.P.I. 

T.I.  Hillside  7361  6531   Santa  Monica  Blvd. 
HOLLYWOOD   M.    CALIF. 


DUALL  MOLDING  CORP. 

Injection   and   Compression    Molders 

Toys — Novelties 

Ornamental   Plastics 

and    Metal   Specialties 

Complete  Teot   Room    Facilities 

267-271   Wycho*  St.          Brooklyn.  N.  Y.          MAin   S-182V 


ANDREW    C.    KARLSTAD 

INDUSTRIAL  DESIGNER 

COMPLETE    PRODUCT   DESIGN   I   ENGINEERING    SERVICE 


414*  VENTURA  CANYON  AVE. 
PHONE— STATE  4-S4W 


SHERMAN  OAKS.  CALIF. 
(A  SUIURI  OF  LOS  ANGELES) 


PLASTIC    CEMENT 

Fait    Drying,   easily   applied,   no    pressure    required. 
For  mounting  plastic  itemt  on  display  cards. 

and  plastic  assembly. 
Artiltbl*  immrd'tltly  in  one  tnd  n*»e  gtllon  cam 

TEXON     INDUSTRIAL 


PROBLEMS 


in  plastics 


Problemi  and  questions  may  be  submitted 
to  this  department  for  answering  by  the  tech- 
nical editors  or  specialists  in  the  industry. 

I  have  designed  a  product  which  I  would  like  to  have  |>roducrd 
in  a  plastics  material.    However,  due  to  my  inexperience  in  this 
field,  I  am  not  sure  that  my  dcM^n  would  be  entirely  right  for 
molding.    Do  you  think  it  advisable  to  have  a  model  made  HIM 
I>erhaps  in  wood — before  proceeding  further? 

R.  S.T.,  New  York,  NY 

.-Iny  good  moldrr,  from  a  study  of  a  drauing  of 
your  design,  would  have  modifications  to  suggest  which 
would  make  for  the  most  efficient  molding  of  your 
product.  In  addition,  however,  it  would  probabl\ 
advisable  to  hare  a  three-dimensional  model  made  of 
plastics  to  serve  as  a  guide. 

*  *         * 

What  is  the  effect  of  moisture  on  flow  in  injection  molding? 

J.  G.,  Perdu,  I  ml. 

Flow  increases  u-ith  increased  moisture  content. 
Some  plastics  (e.g.,  the  cellulose  esters)  absorb  mois- 
ture in  appreciable  amounts  from  the  atmosphere.  The 
amount  of  moisture  absorbed  is  a  function  of  the  rela- 
tive humidity  and  the  temperature.  .Although  moisture 
increases  flow,  the  presence  of  excessive  amounts  is 
undesirable  because  it  sometimes  causes  minute  surface 
bubbles. 

*  *        « 

Is  there  any  way  to  test  a  molded  polystyrene  part  for  sus- 
ceptibility to  crazing?  E.  F.  J.,  New  York,  N.  Y 

J.  H.  DuBois,  in  his  book  "Plastics,"  suggests  this 
simple  test:  Drill  a  small  hole  in  the  part  and  then 
apply  (i  </n>/>  of  kerosene.  Any  tendency  to  erase  in'// 
show  up  quickly. 

*  »         * 

We  are  having  difficulty  in  the  finishing  of  black  phenolic 
handles  which  we  mold.  The  mold  line  which  runs  down  t In- 
center  of  the  handle  must  lie  entirely  eliminated,  and  the  handle 
buffed  to  a  high  lustre.  \Ye  find  that  we  can  eliminate  the 
molded  line  by  buffing  or  sanding,  but  when  this  is  done,  white 
specks  show  up  on  the  handle  We  would  appreciate  any  infor- 
mation you  can  give  us  as  to  how  to  buff  these  handles  and 
eliminate  the  molded  mark,  without  obtaining  the  white  SIM-,  k- 

J.J.  M.,  Chicago.  III. 

In  actual  practice,  the  following  has  been  found  to 
work  successfully  in  suiting  problems  like  yours:  H'ifA 
the  use  of  a  14"  abrasive  belt  coated  with  No.  ISO 
emery,  to  which  grease  stick  has  been  applied,  the  mold 
line  is  easily  removed.  A  light  buffing  operation  after 
this  polishing  operation  to  take  off  the  grease  left  on 
the  handle,  buffs  the  handle  to  a  high  luster  ttithuut 
cutting  down  to  the  white  spots. 

*  •          e 

What  plastic,  material  do  you  recommend  as  having  excellent 
electrical  pro|K-rtics,  and  which  would  be  physically  Mrmii: 
enough  to  be  used  as  a  structural  support? 

B.  B..  Toledo.  Ohio 

W  e  suggest  melamine  laminates  as  hating  the  prop- 
erties you  desire. 


96 


pL.-t5.ri  r  M 


-i;n  KMI'.KK 


SPE  Genera/  Show  Committee  Meets 

The  first  meeting  of  the  General  Show  Committee  of  the 
Society  of  Plastics  Engineers  was  held  at  Normandy  House, 
Chicago,  on  August  6,  to  formulate  and  discuss  plans  for  the 
organization's  exposition,  scheduled  for  January  28  through 
February  2,  1947.  Among  other  matters,  it  was  decided  that 
daily  hours  of  the  show  should  be  from  1  to  10  p.m.,  with  attend- 
ance restricted  to  SPE  members  and  registered  guests  between 
the  hours  of  1  and  4,  and  open  to  the  general  public  from  4  to  10 
on  the  first  four  days ;  on  the  two  final  days  the  public  would  be 
admitted  from  1  to  10. 

J.  O.  Reinecke,  of  Barnes  &  Reinecke,  is  general  chairman, 
with  J.  A.  Hill  as  vice  chairman.  Mr.  Reinecke  delegated  duties 
to  the  various  show  committees  which,  with  their  chairmen,  are 
as  follows:  Banquet  committee,  C.  C.  Henry;  publicity,  J.  A. 
Boyajian;  legislation,  L.  H.  Amrine;  hotels,  T.  E.  Richards; 
meetings,  W.  L.  Hess ;  reception,  Arthur  Lovgren ;  decorations, 
Forest  Wilson;  entertainment,  Clarence  McCormick;  exhibits, 
W.  B.  Hoey,  with  E.  E.  Woodman  as  vice  chairman ;  women's 
committee,  Mae  Wirth ;  public  relations  counsel,  R.  R.  Smith. 


Exchange  of  Technical  Data 

Approval  of  an  exchange  of  technical  research  data  between 
the  Printing  and  Allied  Trades  Research  Association,  London, 
known  as  PATRA,  and  the  Packaging  Institute,  Inc.,  N.  Y., 
has  been  voted  by  directors  of  the  latter-named  organization. 
The  consolidation  of  research  facilities  thus  effected  will,  it  is 
expected,  be  of  benefit  to  both  groups.  The  PATRA  organiza- 
tion, through  its  packaging  division,  maintains  laboratories  and 
library  facilities  to  advance  Britain's  studies  in  all  phases  of 
paper,  synthetic  materials,  glass  and  metal. 


Second  SPI  Low-Pressure  Industries  Conference 

Plans  for  a  second  annual  conference  of  the  Low  Pressure 
Industries  Division  of  the  Society  of  the  Plastics  Industry  have 
been  announced  for  January  23  to  26,  1947,  at  the  Edgewater 
Beach  Hotel,  Chicago.  The  conference  is  to  include  an  exhibit 
and  a  series  of  technical  papers. 

At  the  first  meeting  of  a  reorganized  eastern-western  steering 
committee,  led  by  J.  E.  Stokes,  chairman  of  the  division,  pre- 
liminary arrangements  for  the  conference  were  formulated. 
These  included  repeating  the  "personal  contact  plan"  and  non- 
commercial plan  of  exhibiting  which  were  used  at  the  division's 
first  aimual  conference,  and  a  symposium  of  technical  papers  to 
be  held  on  January  23  and  24.  It  was  decided  that  the  exhibit 
should  be  continued  through  January  25  and  26  in  order  to 
provide  non-industry  spectators  an  opportunity  to  attend. 

Robert  E.  Brinkema,  of  Egmont  Arens,  was  appointed  general 
chairman  of  the  Conference,  and  the  following  members  have 
been  appointed  to  head  committees  as  designated :  Cecil  Arm- 
strong, Armstrong  Plastics  Co.,  and  Paul  R.  Hoffman,  co- 
chairmen,  publicity  committee ;  T.  W.  Noble,  Fabricon  Products, 
Inc.,  chairman,  program  committee;  and  Dr.  Lawrence  J.  Mar- 
hoefer,  chairman,  exhibit  committee. 


Cleveland  SPE  Section  Holds  Outing 

The  annual  outing  and  dinner  of  the  Cleveland  Section  of  the 
Society  of  Plastics  Engineers  was  held  on  August  5  at  the 
Richmond  Country  Club. 

Technical  Convention  Dates  .Announced 

October  23,  24  and  25  have  been  announced  as  the  dates  for 
the  technical  convention  to  be  held  by  the  American  Society  of 
Body  Engineers,  Inc.,  at  the  Rackham  Memorial  Bldg.,  Detroit. 


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Name  . 
Company 
Title 

Address   .  .    ' 
City  &  State 


SEPTEMBER  1946 


PLASTMCS 


97 


Advertiser 

Aaron  Machinery  Co. 
Accurate  Spring  Mfg.  Company.. 
A|ai  Steel  A  Forge  Co. 
American    Photocopy    Equipment 

Co. 
Amos   Molded   Plastici     ......... 

Arrow  Plartics  Company 
Auburn    lufton   Works.   Inc.    . 
Austin   Tool   1   Mfg.   Co 

lamberger,    A 

lames  a    Reinecka.   Incorporated 

llaisdell    Pencil    Co 

loice-Crana    Company 
loonton   Molding  Company    .. 
Irilhart.    Arnold.    Ltd 

Cee  lee    Mfg.    Company,   The 
Cello-Plastic   Chemical    Co. 
Celluplastic   Corporation 
Chemaco  Corporation 
Chicago  Die  Mold  Corporation   . 
Clark,   Robert  H..  Company 
Consolidated    Molded    Products 

Corporation 

Consolidated    Staple    Co.,    Inc 
Continental  Plastics  Corporation 
Cruver   Manufacturing   Company 
Cumberland    Engineering    Co 

Defiance  Machine  Works  Inc. 
Detroit  Mold  Engineering  Co 
Duall  Molding  Corporation 

Ekstrom,   Carlson   t    Co. 
Engineers    look   Service 

Famco  Machine  Co. 
Felsenthal,  G.,  A  Sons 
Fisher   Chemical    Company 

General   Chemical   Company 

General    Electric   Co. 

General  Industries  Company,  The 

Genng    Products,    Inc 

Girdler   Corporation,   The 
Goodman.   Benjamin    Inc 
Goodrich,    I.    F..    Chemical    Co. 
Grays  Harbor  Industries.   Inc. 
Great  American  Color  Company 
Grlgolelt    Company,    The 

Hydraulic    Press   Mfg.   Co..  The 

Industrial   Equipment  Company 
Interlake  Chemical  Corporation 


Agency 


.Russell  T.   Gray,   Inc 
Stockwell    t    Marcuse 

.Arthur    Meyerhoff   A   Company    . 
Sidener  and  Van   Riper,   Inc.    .... 
.Powerad    Company,    The 
.Charles    L.    Rumrlll    t    Company 


n 
x 


.  f7 
20 

n 

•  i 

.   «4 


Advertiser 


Agency 


fage 


H.  W  Fairfai  Advertising  Agency,  Inc.  74 
lehel  and  Waldie  and  Iriggs  Advg.  II 
Richard  A.  Foley  Adv.  Agency,  Inc.  W 

Wendt    Advertiiing    Agency      I* 

Franklin  Fader  Company,  The  10 

Henri   Le   Mothe   Agency  lack  Cover 


McCarty  Company.  The 
M.  C.  Diedrich 
0     T.    O'Connell    Company 
.  lehel   and  Waldie  and   Iriggs  Advg. 
Wait-Marquis,    Inc. 

Walter  J.  Gallagher.  Advertising  

Jim    Duffy    Company 

Richard    Thorndike    Precision    Advg.    . 

Beeson-Faller-Reichert,    Inc 

Charles  M.   Gray  1  Associates   

Gunn-Mears    Advertising    Agency 


17 

n 

4« 

27 
»4 


S3 
W 
M 

12 
74 

i 
13 

te 


Cummings.   trend  A    McPherson,   Advg.  H 

Western   Advertising  Agency  .         14 

Lieber   Advertising    Co.  67 

Freiwaid    A    Coleman    Advertising    .      .  .99 

.  Afherton  A  Currier,  Inc.  Second  Cover 
lenton  A  Bowles.  Inc.  .  .  7 
Fuller  A  Smith  A  Ross,  Inc.  ..  .13 
M.  C.  Diedrich  .  I 
Roche.  Williams  A  Cleary.  Inc « 


35 


•3 
57 


Grlswold-EsKleman  Co  .  The 
Frederick   E.    laker  and  Associates 

Mace  Advertising  Agency,   Inc.    . . . 

Jay   H.    Mailh   Company,  The    3 

Louis   F.    Herman  Advertising   Agency      tJ 
Stanley    Pflaum    Aisoclates  5 


IF  YOU  WANT  OUTLETS 
CONTACT  US 


Anything 


or 


thing    pertaining    to    S 
Genera)    Merchandising 


Smokers    Artides 
and    Novelties 


We  Contact  Jobbers  and  Chain  Store  and 
Department  Stores  from  Coast  to  Coast! 

(Wm  U  til   i.,,.  Our  »~~  ^Mounta  (/  l 


M.  B.  SIEGEL 

ASSOCIATES 
FACTORY    RlmiSCNTATIVIS    AND    DISTRIBUTORS 

41  t  ADAMS  ST.  CHICAGO  J,  ILL. 


FOR    SALE 

I — Himr.h-Sulzer     Hydraulic     Corapresalon     Molding 

PreMes,  capacity  160-200  tons  each. 
2 — 60-ton  Oil  Oear  Pumps  Included  with  above. 

CHARLES   I.   TAOER 
Consolidated  Staple  Co.,  Inc. 

14    W.ett.r    it  New    Y.rk.    N.   V. 


International    Plattict   Harmonica 

Corporation    Marcel  Schulhofl  *  Company 

Karlstad.  Andrew  C. 

Kingiley  Gold  Stamping  Machine 


Co. 

Kirk,  F.  J.,  Molding  Co 

Klelnberger,  Richard  C. 
Kraiilovtky,   David   (  Samuel, 

Trucking,   Inc 

Kreiger  Color  t  Chemical  Co.   . 
Kuhn  <  Jacob  Molding   «  Tool 

Co.  

Kun-Kaich,   Inc 


.  Continental   Advertising   Service 
Cory    Snow.    Inc 


.Warren    P     Fehlman    Adv.    Co. 

Eldridge-Northrop,    Inc. 
Kircher.    Helton   <    Collar!    .... 


La  Rose,  W.  T.,  t  Associates  .. 
Maas  A  Waldstein  Company  . . 
Mack  Molding  Company,  Inc.  . . 
Magnetic  Plastics  Company,  The 
Metaplast  Company,  Inc. 


.  65 

H 

.  12 

.  n 

.  n 


H 

a 
it 

is 

14 


Aldridge   and    Preston   Advertising 

Doyle.  Kitchen  A  McCormick.   Inc. 

George  Homer  Martin    43 

Gregory    House,    Inc 91 

.Sam   J.    Galley   Company    » 

Michigan  Chrome  A  Chemical  Co.  Karl   G.   lehr  Advertising  Agency    95 

Mosinee   Paper   Mills  Company          Klau-Van     Pieterson-Dunlap     Associates, 

Inc 31 

National  Lock  Company     L.  W.   Ramsey  Advertising  Agency,  The  75 


National  Organ  Supply  Co. 
National  Plastics  Products  Co  .  . 
Nicholt  Hard  Chrome  Service  ... 
Oiley,  John  H.  Company 

Palley  Supply  Company    

Plaskon    Division,    Libbey-Owens- 
Ford   Glass  Company 


.P.  W.   Price,  Advertising 
Joseph   A.   Wilner  Company,  The 


.  n 

U 
.  »0 


J.   I.  Sebrell   Advertising  Agency 
Meldrum    t    Fewtmlth    Advertising     21.  W 


W  O  Nattleton  A  Associates  . 

M 

Printloid,    Inc  

T>; 

Radio  Receptor  Company,  Inc. 
Rayon   Processing  Co.   of   R.   1., 

Inc  
Rohm  A  Haas  Company  

.O.  S.  Tyson  A  Co.,  Inc  

Richard  Thorndike  Precision  Advg.  . 
.  Newell-Emmert  Company 

,..  n 

...  73 

Walter  W.  Wiley  Advertising    .........  T7 

Craig    E.    Dennison   Advertiiing    Agency  *t 
Ehrlich    1    Neuwlrth    .................       7« 


McLain    Organization.    Incorporated 
Kenyon   t   Eckhardt.   Inc.    ........... 


United  States  Gypsum  Company 
Van  Dorn   Iron  Works  Co..  The 


Schwarti   Chemical    Company 
Siegel,   M.   I.,  Associates     . 

Sossner         

Steiner,   George,   Company    . . . 
Stokes,  F.  J.,  Machine  Company 

Tennessee   Eastman  Corporation 

Teion    Industrial    Corp Te 

Fulton   Morrissey  Company    IOC 

Hubbell  Advertising  Agency,  The   17 

Watertown  Manufacturing  Ce.,The.R.  T.  O'Connell  Company   ...  It 

Worcester  Moulded  Plastics  Co.      C.  Jerry  Spaulding,  Inc Third  Cover 

Wrigley,  Wm  ,  Jr.,  Company            Ruthrauf)  A  Ryan,  Inc.  . .  M 

Yardley    Plastics   Co.          .    .    .         .Iyer  A  Bowman  Advertising  Agency  47 

CLASSIFIED    ADVERTISING 

FAST  Selling  Plastlrs  Line — Available  for  salesmen  with  good  following 
among  the  Notions,  Novelty.  Tobacco.  Stationery,  and  Drug  Jobbers — also 
chain  stores.  Several  territories  open.  Commission  basis.  Write  in  full 
details  to  Box  103,  %  Plastlrs,  isr,  N.  Wabash  Are..  Chicago  1.  Ill 


SMALL  Injection  plant  with  new  8  ox 
connection  with  eastern  molder  to  m 

s;   N. 


In  Southern  Cal.  would  like 
for  and   represent    same   on    »<•«: 
Avr  .   Chu-ai|..    I.    Ill 


OPEN  time  on  new  S  ox  Injection  press  reasonable  rate,  rnu  furnish  ma- 
terial Box  1*5,  %  Plastics.  185  N.  Wabaah  Are.,  Chicago  1.  HI. 

Al   lt\  I.IC   Sh.vl       K'lrt      TuliiTlu'   I  "t    I"   Si.-,-        Wi-    "ill   MlpplT   Miull   nuatltl- 

tles  of  Plexlglas.  Luclte,  or  Polystyrene  sheet,  rod  or  tubing  for  experi- 
mental or  model  work.  We  maintain  diversified  storks-  of  most  sizes  of 
Acrylic  and  some  slees  of  Polystyrene;  also  cements  and  dies.  Fabricat- 
ing Manual  2.r>c.  price  list  free.  House  Beautiful  Plastics.  Depl  I1. 
5534  W.  Harrlaon  Bt..  Chicago  44.  Illinois.  _ 

WHAT    I-  in-     you    for     -.ill      '  .  >i.-..,i,  »lv    .-].     i     !..    N<-«     Kr.i:l.ii"l     fai-mrles' 

Brokerage  Basis.  If  you  are  not  covering  this  territory  at  present  please 
get  In  touch  with  us.  Box  1*6.  %  Plastic*.  185  N.  Wabuh  Are..  Chicago 
I.  111. 


KXI'OKT:    Xrlglan    linn    n.'.T.-s|e.l    In    mrn.-y    and    Importstii.n    "f 
novelties  and  sundries.     The  General  Angla-Belgtan  Syndicate,  11  Craaf 
l>e  Smet  Oe  Naeyerpleln,  Ghent,  Belgium. 

HELP    WANTED 

SALESMAN  Wanted  :  Salesman  with  retail  follewlng  In  plastic  Him 
wanted  to  carry  additional  line  of  plastic  film  edging  which  Is  used  In 
kitchens,  closets,  and  for  trimming  plastic  Items.  Kicellent  connection 
for  man  carrying  this  type  material.  State  experience  and  territory 
ll.'lili  H.n  |H7.  •-.  I'lu-tirv  Kinplrr  State  IIMs  .  New  York  City.  N  V 

WASTM):  Mi-rlianlcal  Engineer  Kiperlenced  In  Injection  molding  of 
plastics  and  die  casting  of  line  and  aluminum  A-l  Job  In  supervisory 
capacity  with  congenial  working  conditions  for  A-l  man  Trl  State 
I'laMIc  Molding  Co.,  P.  O.  Box  3ST.  Henderson.  Kentucky. 

SITUATION*    WANTED 

<  HKMU'.M.  Knglneer.  I>egrees  from  Spain  and  Rngland  :  six  years'  ex- 
perience :  fluent  Spanish  and  Portuguese,  thorough  knowledge  of  1'U'tlr't 
Technology  and  Plant  layout  for  both  Thermo-settlng  and  Thermo  plastic 
Materials;  experience  In  aaJea  of  Plastic  Materials  and  PlastlO  Ma- 
chinery. neslrea  position  with  progreulve  Plastlc'i  or  Plaatlc's  Ma- 


travel. 


Firm  a<  Rxport   Manager  or  Foreign  Representative.     Willing 
Box  108,  •  1*5  N.  Wabash  Ave..  Chirage  1,  Illino 


I •  I .  \  S  T  i  t 'S 


SKPTKMHKR  1946 


PROTECTIVE  AND  DECORATIVE  COATINGS 

Edited  by  Joseph  J.  Mattiello 

Fifth  volume  in  a  series  concerned  with  the  science  of  pro- 
tective and  decorative  coatings,  this  book  considers  problems  of 
the  industry  from  an  analytical  viewpoint.  It  is  divided  into 
five  chapters,  which  actually  constitute  sections,  titled,  respec- 
tively, "The  Analysis  of  Resins" ;  "Analysis  of  Drying  Oils" ; 
"Laboratory  Testing  of  Metal  Finishes";  "Special  Character- 
istics of  Pigments  in  the  Visual  and  Infrared  Bands";  and 
"  Resinography." 

The  term  "resinography,"  coined  by  the  authors  of  the  chapter 
which  it  heads,  is  explained  as  denoting  "the  graphic  study  of 
resins  and  plastics,"  being  analagous  to  such  terms  as  "metal- 
lography" and  "mineralography."  It  is  concerned  with  "the 
structure  of  resins  and  its  correlation  with  other  physical- 
chemical  properties  involved  in  practical  performances." 

Classification  of  resins  according  to  their  chemical  composi- 
tion as  well  as  from  an  analytical  standpoint ;  methods  of  treating 
resins — analytical  as  well  as  normal  physical  and  chemical  pro- 
cedures ;  how  physiochemical  properties  of  the  resins  are  used 
in  resin  analysis;  spectro-chemical  techniques  of  X-ray  radi- 
ography and  diffraction,  ultraviolet,  visible,  infrared,  and  Raman 
spectroscopy — all  of  these  topics  are  treated  with  in  detail,  as 
are  the  other  aspects  with  which  this  book  is  concerned — John 
Wiley  &•  Sons,  Inc.,  New  York,  N.  Y.,  662  pages,  $7.00. 


DoALL   INSTRUCTION    PROGRAM 

Prepared  by  the  DoALL  Technical  Institute 

Primarily  intended  for  use  in  educational  and  vocational  insti- 
tutions, here  is  a  book  which  can  also  be  extremely  useful  to 
companies  in  the  instruction  of  trainees.  Volume  I  of  "Instruc- 
tion Programs,  DoALL  Machine  Tools  &  Gages,"  it  is  pre- 
pared as  a  comprehensive  guide  for  training  operators  of  DoALL 
equipment. 

The  instructional  material  contained  in  the  book  covers  all 
aspects,  applications,  and  operational  techniques  of  contour  saw- 
ing, as  well  as  all  phases  of  sawing  and  shaping  in  all  types 
of  material.  It  is  divided  into  five  parts.  The  first  section 
of  the  book  deals  with  conventional  sawing  procedures,  and 
the  second  section  is  concerned  with  high  speed  sawing.  Work 
projects  and  tests  to  be  given  trainees,  as  well  as  grading  data, 
are  included. 

Stating  that  contour  sawing  is  a  vocation,  the  DoALL  com- 
pany feels  that  use  of  this  instruction  program  will  enable  oper- 
ators to  recognize  sawing  applications  which  would  not  other- 
wise be  considered  as  such,  with  ultimate  results  of  considerable 
saving  in  time,  material  and  manpower. 

The  volume  is  profusely  and  clearly  illustrated  with  photo- 
graphs, sketches,  and  tables,  and  is  sturdily  bound. — DoALL 
Co.,  Minneapolis,  Minn.,  263  pages. 


PLASTICS 

By  A.  J.  Locltrey 

The  third  edition  of  a  book  prepared  primarily  for  use  in 
schools  and  by  the  hobbyist,  giving  clear  and  concisely-prepared 
information  of  benefit  to  the  student  or  tyro  in  the  plastics  craft 
field.  The  data  in  this  edition  has  been  expanded  and  includes 
details  on  current  developments,  with  an  entire  new  chapter  on 
the  use  of  acrylics.  The  "Where-to-Buy-It"  section  has  been 
completely  revised  and  brought  up  to  date,  giving  sources  of 
supply  of  materials,  tools,  and  equipment  required  for  the  type 
of  work  with  which  the  book  is  concerned. 

There  are  twenty-seven  chapters  and  an  index,  and  the  book 
contains  a  large  number  of  photographic  illustrations,  as  well 
as  diagrams  and  sketches. — D.  Van  Nostrand  Co.,  Inc.,  New 
York,  N.Y.,  239  pages. 


The  Statue  of  Athena,  highest 
example  of  Greek  art,  was 
sculptured  by  Phidias.  This 
Greek  goddess  of  wisdom, 
made  of  ivory  and  gold,  stood 
in  Athens,  Greece.  Many  man- 
ufacturers of  new  and  old  pro- 
ducts are  using  wisdom  in 
considering  plastics.  Be  wise 
and  choose  Nosco,  successful 
molders  of  plastics,  to  <=: 
help  you  attain  a  pro- 
duct advantage. 


Oi»»  of  a  i«rf«  covering  Wondtft 
of  rti*  World.  Can  you  na/n*  torn* 
of  the  ofher,?  Watch  NofCo'l  next  04. 


NOSCO   IS  QUALIFIED   AND  CAN  HELP  YOU.  WRITE  TODAY 

yVQSCO    Plas+Ics 


ISION       OF 

NATIONAL     ORGAN     SUPPLY     CO 


ERIC,    PA 


BENZOY1 


PEROXIDE 


SEPTEMBER  1946 


PLASTICS 


99 


IT'S  HERE... THE  ONE  REALLY 

V 


CASTING  MATERIAL 


r 


for  Keller,  Gorton,  and 
duplicate  patterns; 

master  patterns  and 

models;  dies  for  forming 

plastics  and  soft  metals;  drill  jigs; 


Long  ago,  U-S-G  realized  the  need  for  a  new  casting 
material  combining  the  advantages  of  synthetic  resins 
and  gypsum  cement. 

Today,  after  intensive  research,  we  present  Hydro- 
mite*,  the  answer  to  that  need. 

Here,  in  powder  form,  are  synthetic  resins  and  other 
plastics  combined  into  one  versatile  material.  And, 
Hydromite  not  only  offers  the  advantages  of  resins  and 
gypsum  cement,  but  also  eliminates  many  weaknesses 
of  both. 

It's  easy  and  quick  to  mold;  has  less  shrinkage  than 
-\  nt  !ii-tii-  resins;  casts  and  forms  in  simple,  low-cost 
molds  and  dies  without  the  need  of  elaborate  shop 
equipment. 

Its  dimensions  are  more  permanently  stable  than 
most  plastics;  and,  used  according  to  directions,  it  is 
self-setting  to  a  strong,  dense,  hard  and  tough  product. 

Get  full  information  on  this  sensational  new  casting 
material  now  .  .  .  just  mail  the  coupon. 

•llrdranltr  !•  •  irartrmark  K.,  I'  s  l-.,i  (MI  lo.n-.n- 
MM  »t  |»uim  wnixMtiaiu  m*nulM-tuml  by  United  SUM 
<  ,vl»um  Company. 


pottery  cases; 
cast  novelties; 
checking  fixtures 
and  core  boxes 


UNITED  STATES  GYPSUM  COMPANY 

Dept.  P-9-46,  Chicago  6,  lUinoii 

Gentlemen :  Plena**  trod  me  a  copy  of  your  Hydromite 

bulletin.  No.  IGL-2A. 

Name ... 

Addreo . 

City..  /xii*'  .-'t.itr 


United  States  Gypsum 


Gypsum    •    lime 


100 


For  Building  •  For  Industry 

Steel    •    Insulation    •    Roofing    •     Paint 

1'RINTKH  IV  r  HA. 

PI.  AST  I  fS  SKITKMKKK 


In  this  plant,  modern  as  tomorrow,  the 
doors  never  close.  Inside  there's  a  hustle  and 
bustle  24  hours  a  day.  Men  and  women  are 
at  work,  yes  —  and  at  the  right  time  just  as 
hard  at  play,  too.  But  their  chief  concern  is 
production  of  custom  injection  moulded  parts 
and  products  of  plastics.  Die  making  alone 


occupies  one  entire  floor.  Another  space 
equally  large  is  devoted  exclusively  to  assem- 
bly, finishing  and  inspection.  Every  square 
inch  of  ground  floor  space  is  filled  with 
moulding  equipment,  with  just  as  much  room 
again  for  the  storage  of  raw  materials.  This, 
in  essence,  is  your  plant  —  your  source  of 
quality  plastics  in  volume.  In  it  an  abundance 
of  versatility  is  at  your  command.  The  doors 
are  always  open  —  TO  YOU. 


I 


F"nr 

1 


WORCESTER  MOULDED  PLASTICS  CO. 

14  HYGEIA  STREET,  WORCESTER  8,  MASS. 

17   East  42nd  St.,   New  York   17,   N.  Y. 
120   West  Chippewa   St.,   Buffalo    2,   N.   Y. 


BLUE 
PRINT 


\ 


offers  a  complete 
MOLDING 
SERVICE 


MOIJMNG 


From  design  to  finished  product. 
From  choice  of  material 
to  type  of  manufacture 
ARNOLD  BRILHART  LTD.  offers  a 
complete  unbiased  service  to  you. 


A 

FINISH 


IN    COMPRESSION,    INJECTION,    TRANSFER 
MOLDING    AND    PRECISION    MACHINING. 


ARNOLD       BRILHART      LTD. 

433    MIDDUNECK    ROAD       GREAT    NECK,   N     Y. 
PHONE:    GREAT    NECK    4054 


OCTOBER 
1946 


Some  more  of  the  thousands  of 
applications  for  GEON  raw  materials 


["""'HEY'VE  made  Hy  swatters  and  shower   cur- 
JL  tains  —  upholstery  and  floor  tiles  —  wire  insula- 
tion  and  acid  tank  linings— and  thousands  of  other 
useful,  attractive  products  from  GEON  polyvinyl  raw 
materials.  Here  are  some  more— raincoat,  hat,  matching 
handbag,  shoes,  suitcase  —  colorful,  nice  to  look  at,  long- 
lasting,  easy  to  clean. 

GEON,  as  can  be  seen,  is  an  extremely  versatile  material 
That's  because  of  its  unusual  properties  which  may  be  com- 
pounded into  finished  products  in  a  wide  variety  of  combina- 
tions. Products  made  from  GEON  may  be  made  to  resist 
water,   chemicals,   sunlight,   heat,   cold,  oils   and  greases, 
abrasion,  mildew,  ozone,  and   most  other    normally  de- 
structive factors.  They  may  be  flexible  or  rigid,  clear  or 
opaque,  brilliantly  or  delicately  colored. 

And  don't  forget  that  GEON  can  be  pressure  or  injection 
molded,  extruded,  calendered  or  cast  into  sheet  or  film.  In 
solution   or   latex  forms  it  can   be  applied  as  coatings 
for  fabrics  and  fibres  of  all  types  as  well  as  for  paper 
and  cardboard.  There  are  applications  for 
dlON    in    i-i-ery  home,    c/cr)  industry. 


lor    more    information    about 
(.1  <  )N.  please  write  Oept.  LJ-10 
B.    I.    Goodrich     Chemical 
Company,    Hose-    Building. 
Cleveland  I  S.Ohio.  In  Can- 
ada: Kitchener,  Ontario. 


anil  I'.TiU-.  : 


Geon 


B.  F.  Goodrich  Chemical  Company 


A  DIVISION  Of 
THE  6  I  OOODIICH  C( 


Built  to  produce  a  multitude  of  small  thermoplastic  parts,  the 
H-P-M  four  ounce  injection  molding  machine  is  being  widely 
selected  by  moiders  demanding  high  quality  parts,  low 
production  costs  and  high  speed  operation. 

The  operating  features  of  the  H-P-M  four  ounce  machine 
art  legion  .  .  .  fast  plasticization  with  two  zone  electric  heat; 
straijht-line  hydraulic  mold  clamp,  providing  positive  mold 
sealin  .  rapid  die  change-over  and  many  other  cost  saving 
features  H-P-M  injection  machines  are  powered  by  the 
reliable  h  °-M  operating  system.  All  hydraulic  pumps,  valves 
and  control  are  designed  and  built  by  H-P-M,  guaranteeing 
undivided  responsibility  to  the  user. 

For  dependable,  maintenance-free  service,  choose  H-P-M 
"all-hydraulic"  units  built  in  standard  sizes  of  4,  9  and  16 
ounce  capacity.  Machines  can  be  shipped  promptly  from  stock, 

THE   HYDRAULIC   PRESS   MFG.   COMPANY 
Mount   Gilead,  Ohio,   U.S.A. 

8ro».:h   OH,..*,    in    K»»    York,    Philadelphia,    Cincinnati,    Detroit.    O«.»l<jn'J   and   Cr.itu»o. 
e«D/«i«ntati..  t  in  ohet  principal  i 


Writ*  today,  on  your  company 
letterhead,  for  a  free  copy  of 
H-P-M  Bulletin  4502,  describing 
the  outstanding  production  feo- 
turej  of  thif  four  ounc»  H-P-M 
all-hrdraufic  unit. 


INJECTION  MACHINES 

OR    MOLDING    T  H  £  R  M  O  -  P  I  A  S  T  I  C  S 


October,   1946 


plastics 


in  this  issue 


Progress  in  Injrrtion  Molding Jack  D.  Stratton  21 

Insulating  Hi^li  Frequency  Cables 

Ringlanil  M.  S\ru<-fii-r  anil  (.arl  A.  Raahc  2<> 

Shaver  Holder  Uses  Plastics 28 

vl>ri  i.il  l-'ivturc*  Sjienl  l'i>st-M<il<l  Miicliiiifry Hi-rbi-rt  Chase  32 

Molded  Vinyls  Solve  Many  Problems William  Schack  37 

'  mnpression  Mold  Design,  Part  II John  G.  Robb  40 

Fabriraiiiii:  Acrylic  Compacts Gilbert  C.  (.'/<>•«•  4  I 

Motion  in  Christmas  Tree  Lighting Mel  MI-\<T\  46 

Auto  Body  Designed  for  Plastics 50 

know  ^  our  <  !;i><-in>.  Part  I Dr.  (,<-iirfi<'  //.  Hrnthfr  52 

"'IVxIolitc"  Offers  Insulating  Advantages 54 

The  How  and  \\  li\  ul"  Mechanical  Testing Gerard  A.  Albert  56 

l.iiili. -"    \pparrl  Adopts  Plastics I'hil  Ruskirk  58 

\\  alking  on  Air Arthur  Grant  62 

PreM-ntiiin  Precipitation  Static J.  If'.  H  elxh  64 

laminated  Label  Holders  Are  Versatile 68 

Polydicblorostyrene  "DCS"— A  New  Thermoplastic 72 

Art   Needlework   Goes  Modern Harbara  Haer  75 

departments 

I'la-tio  in  Perspective 18       Plastics    Overseas 83 

On  the  Drafting  Board 49      Problems  in  Plastics 85 

Pla«tirs  at  Work 60       Statistical   Data 86 

What'n  New  in  Plastics 77       Industry  Highlights 87 

Literature   Review 80       People 90 

Engineering  News  Letter 81       Association  Activities 92 


COPYRIGHT,    1944 


ZIFF-DAVIS   PUBLISHING  COMPANY 


Editorial  Offices.  1 85  N.  Webath  Ave..  Chicago  I,  III. 


WILLIAM  B.  ZIFF 
Publiikrr 


I.  G.   DAVIS 

I.eneral  Manager 

HERMAN  R.  BOLL1N 
Art  Director 

H.  C.  STRONG 

I  irculatian  Director 


C.   R.    TIGHF. 
All't.  to  Pntliskrr 

GEORGE  BERNER 
Advertising  Director 

H.  I.  MORGANROTH 
Production  Director 


U.mb.. 

MU   o( 

ClrcuUrlofli 


VOLUME  5,  NUMBER  4 

tDIIOKIAL      STAff 

MICHAEL  H.  FROELICH 

Editor 

WILLIAM  SCHACK 

Held  Editor 

V.  E.  GIBBENS 

Associate  Editor 

M.  CHURCH 

Associate   Editor 

LILA   SHAFFER 

Associate   Editor 

GAITHER   LITTRELL 

H  'est  Coast  Editor 

FRED   HAMLIN 

Washington  Editor 

CHARLES  A.  SCOGL AND 

Consulting  Technical  Editor 

WALTER  STEINHARD 

Staff  Pkotoarafher 

ARTHUR  E.  HAUC 

Staff  Pkotografker 

SYDNEY  BARKER 

Art  Editor 


JAMES  A.  CERBONE 
Eastern  Advertising  Manager 

HOY  E.  LUIDER 
Midwest  Advertising  Manager 

WILLIAM  L.  PINNEY 
Western  Advertising  Manager 

BRANCH      OFF/CIS 

NEW  YORK  (1) 
Empire  Stair  Bid*.,  If/  7-0400 

LOS  ANGELES  (14) 
tli  5.  Hill  St.,  TUckrr  9213 

WASHINGTON  (4) 
International  Bldg.,  EXEcuti-.'c  .'.<« 

TORONTO 
21  King  Street,  East 


COVER 

An  assortment  ol  tome  ol 
the  many  stationery  Items 
now  available  In  plastics 
eyidences  the  attractive 
coloring.  1 1  q  h  I  weight 
pleasant  lee),  and  dura 
bilily  ol  these  materials 


Other  Ziff-Davit  Publication*:  Hying,  Popular  Photography.  Radio  Newt,   Radio-Electronic   Engineering. 

r  I..-. 


PLASTICS 


OCTOHKK  1!' If 


O.     1      PLASTICS     AVENUE 


A  GOOD  MORNING-IN   PLASTICS 


/\rise  and  really  shine  with  the  new  Telechron  Musalarm. 
This  wonderful  bedside  companion  combines  a  radio,  a  clock, 
and  a  musical  alarm  in  a  handsome  plastics  case.  And  that's 
where  No.  1  Plastics  Avenue  comes  in  with  experience  in 
designing  and  engineering  so  many  plastics  products. 

The  Telechron  people  insisted  upon  beauty  .  .  .  technical 
perfection  .  .  .  economical  production.  And  they  got  all  three 
in  this  compression-molded  phenolic  case  from  General 
Electric's  complete  plastics  service. 

Maybe  you,  too,  are  planning  to  bring 
out  a  wonderful  new  product.  Whatever 
it  may  be,  don't  overlook  the  fact  that 
plastics  may  be  able  to  do  for  you  what 
no  other  material  can.  Bring  any  plastics 
problem  that  may  arise  to  G.E.  —  the 
world's  largest  manufacturer  of  finished 
plastics  products.  Plastics  Divisions, 
Chemical  Department,  General  Electric 


Company,  1  Plastics  Avenue,  Pittsfield,  Mass.  Ask  for  a  copy 
of  the  new  illustrated  booklet,  "What  Are  Plastics?" 

G-E  Complete  Service  —  Everything  in  Plastics 

Backed  by  52  years  of  experience.  We've  been  designing  and  manu- 
facturing plastics  products  ever  since  1894.  G-E  Research  works  continu- 
ally to  develop  new  materials,  new  processes,  new  applications. 

No. 1  Plastics  Avenue— complete  plastics  service— engineering,  design 
and  mold-making.  Our  own  industrial  designers 
and  engineers,  working  together,  create  plas- 
tics parts  that  are  both  scientifically  sound  and 
good-looking.  Our  own  toolrooms  are  manned 
by  skilled  craftsmen — average  precision  mold 
experience,  12  years. 

All  types  of  plastics.  Facilities  for  compres- 
sion, injection,  transfer  and  cold  molding  .  .  . 
for  both  high  and  low  pressure  laminating  .  .  . 
for  fabricating.  And  General  Electric  Quality 
Control  —  a  byword  in  industry  —  means  as 
many  as  160  inspections  and  analyses  for  a 
single  plastic  part. 


GENERAL  W  ELECTRIC 


General  Electric  plastics  factories  are  located  in  Fort  Wayne,  Ind.,  Meriden,  Conn.,  Scranton,  Pa.,  Taunton,  West  Lynn,  and  Pittsfield,  Mass. 
OCTOBER  1946  PLASTICS  5 


sne\\s 


>Nfth 


I 


i\C 


o 

lbte  in  sa    o  W0u 

dv,ood'^b°r       olo^00^°         ds.  iungi-  ac^s  / 

" 


Department  A- 10 


PENNSYLVANIA   COAL  PRODUCTS  COMPANY 


PETROLIA.  PENNSYLVANIA 

•  Distributed  in  Canada  by  CANADIAN    INDUSTRIES  LIMITED.  Montreal.  Canada 
6  PLASTICS  (HTOBKR   l!Mfi 


TO  ATTAIN  excellence  in 
plastic  molding,  many  steps- 
each  an  essential  part  of  the 
whole  process -must  be  fol- 
lowed through  accurately  and 
thoroughly. 

Every  step  of  the  way— design- 
ing, mold  making,  molding, 
and  finishing-calls  for  the  high- 
est skill  and  experience,  plus 
the  proper  plant  facilities  for 
efficient  production.  Combined, 
these  operations  can  result  in 
quality  molding... plastics  that 
'measure  up"  in  performance, 
appearance  and  cost. 
MACK  experience  and  proven 
methods,  plus  three  completely 
equipped  plants,  offer  plastic 
molding  that  qualifies.  Your  in- 
quiries are  solicited;  address 
Mack  Molding  Company,  Inc., 
100  Main  Street,  Wayne,  N.  J. 


MOLDED 
EXCELLENCE 


MACK  PLANT  AT 
ARLINGTON,  VERMONT 


-  MACK  PLANT  AT 
WATERLOO,  P.O.,  CANADA 


MACK  PLANT  AT    • 
WAYNE,  NEW  JERSEY 


SALES 


IN       PRINCIPAL      CITIES 


OCTOBER  1946 


Why?  At  the  core  of  almost  every  plastic 
problem  is  the  mold.  Vital  factors  in  the 
finished  plastic  part  are  determined  by  how 
well  the  mold  is  engineered.  Constructions 
of  cavities  —  single  or  multiple,  the  use  of 
wedges,  pins  or  complicated  inserts,  holding 
to  extremely  close  tolerances  —  calls  for 
tested  skill  and  long  experience. 

Every  mold  at  Industrial  from  the  simplest 
to  the  most  complex  is  backed  by  twenty-five 
years  of  experience  in  die  making  for 
compression  molding.  For  precision  molds 
that  assure  plastic  parts  of  rigid  tolerance 
and  uniform  high  quality,  Specify  Industrial. 


tiw*Bl , 


Molt 


n  Street 


908  lo** 


.Chicago  ".  «'inoit 
.    sou*  B««<».  <"dion° 


ri..\srn'ti 


OCTOHKK   IHIfi 


AMI     ICA 


It  took  the  American  conception  of 
mass  production  to  put  America  on 
top  .  .  .  and  it  takes  WORK  to  keep 
America  on  the  way  UP!  Free  enter- 
prise that  makes  practical  use  of  great 
technological  advances*  and  multi- 
plies the  benefits  for  everyone,  is  the 


American  way  to  maintain  progress. 
Let's  work  like  Americans,  for  there's 
great  work  to  be  done  .  .  .  together! 


*  Technological  advances  in  creation  of  essential  papers 
for  industry,  and  in  adapting  them  to  efficient  processing, 
are  available  through  MOSINEE.  Call  for  MOSINEE 
paper  technicians! 


PAPER 

MILLS 

COMPANY 


MOSINEE  •  WISCONSIN 


Please  address 

your  letter 

11  Attention 

Dept.  #" 


OCTOBER  1946 


PLASTICS 


ITS  SUPERIOR  QUALITIES  CAN  OPEN  NEW  MARKETS 
AND  HOLD  EXISTING  CUSTOMERS  .  .  . 

Have  you  fully  explored  the  market  for  the  many  products  which  can  be 
made  of  Plaskon  Melamine  Molding  Compound? 

Similar  to  Plaskon  Urea  Molding  Compound  in  molding  properties,  Plaskon 
Melamine  can  easily  be  handled  through  existing  molds  and 

There  are  many  uses  for  articles  made  from  Plaskon  Melamine  Compound 
such  as  buttons,  hardware,  tableware,  special  electrical  devices,  cosmetic 
containers,  closures,  etc. 

Its  exceptional  resistance  to  acids,  alkalies  and  heat,  very  low  moist 
absorption,  and  highly  advantageous  electrical  properties  all  lend  tli< 
selves  to  the  development  of  sales  in  many  fields  of  application. 

Ask  the  Plaskon  representative  about  the  unusual  properties  and  sales 
opportunities  of  Plaskon  Melamine  Molding  Compound. 


PLASKON 


MOLDED    COLOR 


Plaskon  Melamine  Molded  Color  dishware  is  used  by  all  airlines  indicated  here.  Set  pictured  is  in  the  service  of  Pan  American  World  Airways  System. 


me  ideal  applications  of  Plaskon  Jttdamine 


Plaskon  Melamine  Molded  Color  is  used 
for  containers  and  closures  by  a  wide 
range  of  cosmetic  manufacturers. 


(top)  Refrigerator  and  stove  handles  of  Plaskon 
Melamine  Molded  Color. 

(bottom)    Electrical  connectors   of  Plaskon 
Melamine  Molded  Color. 


(top)  Distinctive  closures  of  any  size,  shape  or  coll 
can  be  economically  molded  of  Plaskon  Melamin, 

(bottom)  Millions  of  Plaskon  Melamine  MoldedCoh 
buttons  are  used  for  garment  service  and  enhancemen 


ii 
GERING  ScoteA  jo*  1/au  .... 

FOLLOW-THROUGH  depends  upon  proper  coordination;  action  and 
reaction  perfected  by  training  and  experience.   That  is  the  kind  of  fol- 
low-through you  can  expect  when  Gering  "goes  to  bat"  for  you  in  re- 
processing plastic  residues  or  providing  dependable  powders  for  ther- 
moplastic molding. 


WEARS  of  familiarity  with  thermoplastics  have 
*  sharpened  our  skill,  developed  our  resource- 
fulness to  the  point  where  we  can  provide  you 
the  maximum  values  you  need  in  prime  or 
rejuvenated  plastics.  And  Time  has  demon- 
strated our  unquestioned  integrity. 


Writ.  n>  for  d.tolli! 

Telephone:  CRanford  6-2900 


12 


vfit  oj     lllnylc  I'M  (C7irpiMo/wix/i 
PLASTICS 


if  conversion 


OCTOBER  1946 


[ENOLITE  laminated  plastit 


provides  low  dielectric  losses- 
high  operating  efficiency 


Low-loss    relay    spacers  made  of 
Phenolite  laminated  plastic  serve 
more  efficiently  because  of  the 
exceptionally  low  power  fac- 
tor of  this   remarkable 
insulating    material. 


FOR  electrical  applications,  you're  assured  of  reduced  losses  and  improved  per- 
formance with  Phenolite  laminated  plastic.  Especially  suitable  for  insulation  in  both 
high  and  low  voltage  applications,  it  possesses  a  low  power  factor  at  high  frequencies, 
and  has  an  unusually  low  moisture  absorption.  Its  electrical  properties  change  but  very 
little,  even  when  exposed  to  high  humidity  over  long  periods. 


PHENOLITE'S  rare  combination  of  properties — physical,  mechanical  and  chem- 
ical— makes  it  broadly  adaptable  for  efficient,  economical  use  in  many  industries. 
Light  in  weight  (about  half  that  of  aluminum),  it  is  exceptionally  resilient  and 
high  in  impact  strength  ...  is  resistant  to  abrasion  . . .  possesses  good  machinabil- 
ity  .  .  .  resists  heat  and  moisture  .  .  .  and  is  not  affected  by  solvents  and  oils. 

THERE  are  many  ways  in  which  this  versatile  material  can  serve  efficiently  and 
economically  in  your  products  or  plant  equipment.  For  complete  information, 
write  to  — 


NATIONAL   VULCANIZED    FIBRE   CO 


PHENOLITE  laminated  plastic  ia 
available  in  sheets,  roda  and  tubes 
in  sizes  and  grades  to  suit  your 
requirements.  Write  for  valuable 
illustrated  handbook  outlini  ng 
specifications  and  us«s.It'sFREE, 
of  course. 


Wilmington  99,    Delaware 


Offices  in  Principal  Cities 


OCTOBER  1946 


PLASTICS 


13 


MINIMAL 


VIBRATION    EFFECTS 


Mechanical  vibration  should  not  effect  the  control  point  of  a  reliable  tem- 
perature control  device.  The  FENWAL  THERMOSWITCH  Control  em- 
ploys an  extremely  light  and  stiff  bridge  structure  which  resists  vibration 
and  produces  an  extremely  high  natural  frequency  —  far  above  vibration 
frequencies  encountered  in  industrial  applications.  The  spring  gradient  of 
the  element  assembly  is  non-linear,  therefore  the  entire  system  has  no 
natural  resonance. 

Chart  shows  the  amount  of  motion  in  the  switch  element  assembly  of  a 
FENWAL  THERMOSWITCH  Control  compared  to  Type 
1  and  Type  2  Thermostats  —  when  experimentally  sub- 
jected to  an  oscillatory  motion  of  1  10"  at  2000  cycles  per 
minute. 

The  ability  of  the  THERMOSWITCH  Control  to  hold  to 
set-point  under  severe  vibration  has  led  to  its  use  in  large 
quantities   in   aircraft   and   railroad   applications   as   well   as 
many  other  applications  of  all  types.  This  and  other  unique 
features    of    the    FENWAL    THERMOSWITCH    Control 
make   it   the   ideal   temperature   regulating   unit.    Apply   its 
advantages  to  your  temperature  control  applications.  Com- 
plete   information    in     the    Thermotechnics    Booklet    which    includes    the 
"Fourteen  Facts  in  FENWAL's  Favor"  —  sent  upon  request. 


i-OURTEEN    FACTS   IN 
FENWAL'S   FAVOR 


— Fast  reaction   time 

— Large    heat    sensitive    area,    small 

heat    storage 

— Short  heat  transfer   path 
— Small   temperature   differential 
— Built-in   temperature  anticipation 
6  — Enclosed   assembly 
— Minimal   vibration   effects 
— Tamper-proof  and   sealed 
— Rugged    construction 
— Adjustable      over      wide      temper- 
ature  range 
11. — Minimum    siie 

. — Directly      responsive      to      radiant 

heat 

. — Uniform     sensitivity     over     adjust- 
able  temperature   range 
. — Readily   installed 

*»•  fl  of  *•  "Fourt««n  Facts  in  FENWAL's  Favor' 


FENWAL  INCORPORATE: 

57    PLEASANT     STREET 

ASHLAND        MASSACHUSETT! 

Thermotechnics  for  Complete  Temperature  Regulation 


14 


OCTOKKK   1!M< 


FOR  YOU  ! 


An  interesting  Decimal  Chart  that  saves  time;  gives  diameter, 
area  and  circumference  of  circles,  and  surface  and  volume 
of  spheres,  for  each  additional  fractional  increment  (1/64) 
of  diameter.  4-page  folder,  3-ring  punched.  Yours  upon 
request  on  your  company  letterhead. 


Handles  Materials  Handling 

With  Bonny  at  the  controls  of  one  of  our  ma- 
terials handling  trucks  (we  call  'em  jeeps) — 
look  out!  Because  materials  really  get  some 
fancy  handling  and  so  does  any  unwitting  on- 
looker when  Bonny's  at  the  controls. 

Actually,  this  modern  method  of  materials 
handling  is  just  one  of  the  many  examples  of 
our  modern  plant — keeping  modern  and 
efficient.  Our  jeeps  pack  vital  raw  materials 
neatly — right  up  to  the  ceiling  (when  we 
have  "em) — using  every  cubic  foot  of  storage 
space.  Then,  when  our  molding  machines  get 
empty,  busy  jeeps  hand  down  the  raw  mate- 
rials needed  to  fill  up  hungry  hoppers. 

We  think  efficient  handling  of  raw  materials 
is  one  of  the  important  parts  of  efficient 
molding. 

What  can  we  mold  for  you? 


BOONTON  MOLDING  COMPANY 

MOLDERS  OF  MOST  PLASTICS  BY  MOST  METHODS 


FOR  OVER  25  YEARS 
CUSTOM  ENGINEERS 
OF  MOLDED  PLASTICS 


122  EAST  42nd  ST.,  NEW  YORK  17 


SUITE  1716-P 
MURRAY  HILL  6-8540 


FACTORY— BOONTON,  New  Jersey 


OCTOBER  1946 


PLASTICS 


15 


16 


Pl.ASTiCS 


(HTOHKK  1HJ6 


Crefa 


WHEN  YOU  INVEST  IN  HIGH  FREQUENCY  HEAT 


"VVTHEN  you  invest  in  high  frequency  heat, 
^*  make  sure  of  full  benefits  from  this  elec- 
tronic technique  of  heating  plastics  material  for 
molding.  Get  a  dependable  high  frequency  heat- 
ing unit.  Get  a  Thermex  Red  Head. 

Thermex  ability  to  "take  it"  has  been  a  matter 
of  record  for  years.  Thermex  was  the  first  prac- 
ticable industrial  high  frequency  dielectric  heat- 
ing equipment  put  on  the  market.  The  first  Ther- 
mex units  installed  are  still  going  strong.  Built 
by  the  organization  that  has  been  specializing 
in  dielectric  heating  equipment  since  the  begin- 
ning, the  Thermex  Red  Heads  of  today  are  bound 
to  be  more  efficient  and  dependable  than  ever. 

If  you  are  converting  or  expanding  your  mold- 
ing facilities,  if  you  are  building  a  new  plant, 
find  out  about  Thermex  Red  Heads.  They  con- 
stitute the  most  complete  line  of  high  frequency 
heating  units  for  the  plastics  industry.  Mail  the 
coupon  or  contact  Girdler  branch  offices  at  1 50 
Broadway,  New  York  7;  228  N.  LaSalle  Street, 
Chicago  1;  1836  Euclid  Avenue,  Cleveland  15. 


The  Girdler  Corporation.  Thermex  Division. 

Dept.  PM- 10,  Louisville  1.  Ky. 
Pltase   »end   complete   information   about   Thermex. 


Name Title 

Wrm  Name 

\dtln\\ . 


THE  FIRST  INDUSTRIAL 

HIGH  FREQUENCY  DIELECTRIC 

HEATING  EQUIPMENT 

•Trade  Marie  Reg.  V.  S.  Pat.  Of. 


OCTOBER  1946 


PLASTICS 


17 


PLASTICS 


WHEN  TIIK  Bound  Brook  plant  of  the  Bakelite 
Corj>oratioii  was  hit  by  a  strike  early  last  month, 
the  importance  of  plastics  materials  for  production 
in  many  industries  was  first  realized.  The  New  York 
Times,  for  example,  ran  a  long  story  on  its  first  busi- 
ness page,  beginning:  "Manufacturers  of  automobiles, 
refrigerator-,  communication-  equipment  and  devices 
used  in  the  housing  industry  faced  yesterday  a  new 
obstacle  in  getting  their  full  production  lines  into  full 
-wing — a  shortage  of  component  parts  made  of  various 
type  plastics  .  .  ." 

The  report  went  on  to  quote  molders  as  saying  that 
their  supplies  of  raw  material  would  be  exhausted 
within  three  to  ten  days,  and  to  itemize  a  considerable 
number  of  products  for  which  phenolic  molding  pow- 
der and  polystyrene  were  required. 

While  we  deplore  this  and  other  strikes  in  the  plastics 
industry  and  hope  for  quick  settlements,  we  cannot 
help  noting  that  this  report  in  the  Times  and  other 
newspapers  had  at  least  the  value  of  making  the  pub- 
lic realize  the  significance  of  plastics  in  the  all-over 
production  picture.  It  made  them  aware  of  the  fact 
that,  beyond  the  lurid  popular  notions  of  plastics  doo- 
dads and  fantasies  made  in  some  never-never  land, 
there  are  any  number  of  honest-to-goodness  everyday 
products  in  which  some  plastics  material  plays  a  vital 
part.  The  public  heard — straight  out — about  phenolic 
molding  powder  and  polystyrene ;  the  technical  terms 
which  are  such  a  bugaboo  in  our  informative  labeling 
campaign  were  not  denatured  for  popular  consumption. 
We  hope  it  will  not  take  such  catastrophes  as  strikes 
to  make  the  public  aware  of  the  other  types  of  plastics 

and  of  their  significance  in  our  industrial  life. 
*     *     * 

A    XICWS  release  from  Washington,  D.  C,  reveals 
the  regrettable  information  that  the  patenting  of 
new  inventions  is  being  delayed  by  over  a  year  and 
that  more  than   120,000  applications  now  await  action 
by  the  patent  office. 

According  to  this  charge — made  in  a  public  letter  by 
the  president  of  the  Patent  Office  Society,  an  organi 
/ation  of  inventors,  patent  attorneys,  and  others  in- 
terested in  the  patent  system-  the  princi|>al  cause  of 
the  hold-up  can  be  traced  back  to  the  removal  during 
the  war  of  a  vital  part  of  the  patent  office  from  the 
Commerce  Department  in  Washington  to  Richmond. 
Va.  Whenever  record-  were  needed  ill  one  office,  they 
were  often  found  to  be  at  the  other  or  in  transit  l>e- 
tween  the  two  offices.  Conflicting  rumors  and  state- 
ments that  the  Richmond  office  wa-  to  he  moved  back 
to  Washington  added  to  the  confusion. 

Although  there  is  little  excuse  for  the  inefficiency. 
the  situation  would  not  be  -o  extreme  if  fewer  crack- 


pot  ideas  were  cluttering  up  the  files  and  retarding  the 
consideration  of  worthy  inventions  and  developments. 
The  public  building  administration  is  planning  to 
move  the  Richmond  force  back  this  fall  to  temporary 
quarters  31/*  miles  from  the  main  office  in  Washing- 
ton. Let  us  hope  that  this  change  and  an  expected 
reduction  from  the  number  of  patent  applications 
which  deluged  the  office  in  war  time  will  aid  in  clear- 
ing away  the  backlog  and  rendering  faster  service. 

*  *     * 

THE  ENGINE  in  the  automobile  has  been  so  im- 
proved that  it  performs  more  useful  work  |*T 
gal  of  gasoline  than  it  used  to,  but  to  attain  real  effi- 
ciency of  the  vehicle  as  a  whole  we  might  well  l>e 
spending  more  effort  on  reducing  its  weight.  This 
could  be  accomplished  by  making  it  smaller,  but  that 
apparently  is  out  as  far  as  the  American  public  is 
concerned.  However,  there  is  no  general  opposition  to 
a  reduction  in  the  weight  of  the  materials  used  in  the 
manufacture  of  the  automobile. 

In  this  connection,  the  article  on  page  50,  which 
discusses  the  development  and  manufacture  of  a  lami- 
nated plastics  auto  body,  is  of  considerable  intere.-t. 
Without  speculating  one  way  or  the  other  on  the 
sibilities  for  low-cost  mass  production  of  such  an  auto- 
mobile, we  believe  that  the  experiment  represents  a 
step  in  the  right  direction. 

*  *     * 

THERE  IS  no  doubt  that  one  of  the  chief  virtues 
of  plastics  is  their  light  weight.  In  this  conned  inn, 
two  of  their  leading  non-wood  competitors  are  alumi- 
num and  magnesium.  Trade  sources  estimate  that  1 '  .• 
billion  Ibs  of  aluminum  will  be  consumed  in  the 
ending  May,  1947,  and  that  the  production  of  magne- 
sium for  the  same  period  will  be  about  five  time.-  the 
highest  pre-war  rate. 

Aluminum  is  said  to  be  firmly  established  in  kitchen- 
ware  and  household  appliances.  New  and  sugge-ted 
u-e-  read  in  part  like  a  list  for  plastic-  :  Venetian  blinds, 
golf  clubs,  fruit  crates,  foil  wrappers,  wheelbarrow-, 
heating  and  ventilating  ducts  and  business  machines. 

.Magnesium  i-  being  used  or  contemplated  for  seats, 
landing  gears,  and  engine  parts  .in  transport  planes, 
machine  parts  in  the  textile  industry,  griddles,  broom 
and  brush  handles,  clothes  baskets,  lawntnowers,  wheel 
barrows,  hods,  baseball  masks,  golf  bags,  fishing  rod 
.  skiis,  canoe-  and  hand  tools. 

Whether  plastics,  magnesium,  or  aluminum  pro\r- 
better  for  a  specific  use  will  depend  on  the  degree  of 
weight  saving  desired  or  needed;  other  pro|>ertii 
quired,  such  as  insulating  value  and  resistance  t< 
io-ioii:  or  by  a  combination  of  properties  offering  the 
end  user  the  most  at  the  lowest  price.  i  M> 


18 


PLASTICS 


OCTOBER  1916 


How  to 
Pin  Down 
Production 
Costs ! 


In  1921  plastics  molding  schedules 

jumped  from  a  slow  crawl  to  a  sharp  run  overnight,  as 
semi-automatic  presses  with  knockout  pins  first  came  into 
use.  A  Kurz-Kasch  engineer  shares  much  of  the  credit! 


T 


OMORROW'S  improved  molding  practices  will 

grow  out  of  bright  ideas  simmering  today  in  some  progressive  molding 
plant— paying  dividends  to  the  customers  whose  production  will  bene- 
fit before  the  crowd. 

New  production  ideas  have  been  an  old  Kurz-Kasch  habit  since  the 
birth  of  the  plastics  industry.  See  how  they'll  benefit  you— send  for  your 
free  booklet,  "A  Businessman's  Guide  to  the  Molding  of  Plastics"— on 
your  business  letterhead,  please. 

Kurz-Kasch 


For  Over  29  Years 

Planners  and  Molders  in  Plastics 


Kurz-K.asch,  Inc.,  1413  S.  Broadway,  Dayton  1,  Ohio.  Export  Offices:  89  Broad  Street,  New  York,  N.  Y. 
Branch  Sales  Offices:  New  York  •  Chicago  •  Detroit  •  Los  Angeles  •  Dallas  •  St.  Louis  •  Toronto,  Canada. 


OCTOBER  1946 


PLASTICS 


19 


These  pictures  show  some  of  the 
men  and  equipment  in  the  new 
mold  shop  added  to  Amos  facilities. 


FO*  ciecrmcAi  AfPUANCti 


fj  Jij     £/ 


offlCf  MACHINES  0>  IMDUSTtML  lOUirMIKT 


IATKIIOOM  PUTVUIS   i.  Miticu.  MCISSOMK'^V. 


\ 


A  completely  new  and  modern  tool  plant  in  Indianapolis  .  .  , 
with  more  new  machinery  to  make  molds  for  Amos  .  .  , 
and  four  of  the  best  mold -makers  in  the  plastics  industry 
to  control  this  most  important  factor  in  your  plastic  mold- 
ing job— that's  the  latest  addition  to  constantly  enlarging 
Amos  facilities. 

To  do  your  plastic  molding  jobs  exactly  right,  Amos  insists  thai 
your  molds  must  be  engineered  and  built  right— from  begin* 
ning  to  end! 

Complete  and  rigid  control  of  your  molding  job,  from  engineering 
and  mold-making  to  production  and  finishing  . . .  with  every 
step  handled  by  broadly  experienced  plastics  engineers  and 
specialists  who  excel  in  creating,  tooling  and  producing  in- 
jection molded  parts  and  products— that's  the  service  Amoi 
offers  YOU!  Just  send  your  drawings  or  write  us  what  you 
have  in  mind  to  be  molded  in  plastics— Amos  u-ill  do  it  right! 

AMOS  MOLDED  PLASTICS   •    EDINBURGH,  INDIANA 

Divliion  of  Amoi- Thompson  Corporation 


20 


OCTOBER  l!Uh 


Core  being  inserted  in  cold  cavity  of  die  mounting 
which  casts  "Tenite  II"  theater  marquee  letters. 
Mounting  installed  on  machine  permits  changes  of 
cores  and  cavities  in  10  min.  (Left,  foreground) 
ejector  plate,  core  and  cavity  used  to  cast  an  "E" 


(Jack 


ALTHOUGH  it  may  appear  to  a  given  molder  occasion- 
ally— especially  when  things  are  going  extremely  bad 
— that  he  is  bearing  the  cross  for  the  whole  plastics  industry, 
there  is  no  doubt  that  his  trials  and  tribulations  are  being 
paralleled  in  similar  plants  all  over  the  country.  At  other 
times,  when  things  are  going  smoothly  and  he  feels  that  the 
gods  are  smiling  on  him  with  special  favor,  there  is  also  no 
doubt  that  his  accomplishments  and  successes  are  being  ap- 
proximated or  duplicated  throughout  the  nation.  This  simi- 
larity of  experience  and  accomplishments  stimulate  competi- 
tion, which  in  turn  spurs  the  development  of  better  products, 
improved  processes,  and  faster  production. 

With  these  facts  in  mind,  let  us  look  at  some  of  the  activi- 
ties of  Plastic  Die  &  Tool  Corp.  of  Los  Angeles,  whose  prob- 
lems and  successes  characterize  in  varying  degrees  the  de- 
velopment of  the  injection  molding  industry  as  a  whole. 
Three  of  the  engineering  and  molding  jobs  of  which  this 
concern  is  proud  include  the  production  of  theater  marquee 
characters,  the  molding  of  a  screw  thread  without  loose 
inserts,  and  the  designing  and  production  of  a  number  of 
multiple  cavity  dies  (including  one  with  49  cavities  to  pro- 
duce an  assembly  with  moisture  tight  contacts)  which  are 
said  to  give  unusual  performance. 

Molding  by  Plastic  Die  &  Tool  Corp.  of  cellulose  ace- 
tate butyrate  alphabetical  characters  for  theater  marquees  in- 
volves 45  interchangeable  molds.  There  are  two  fonts  of 
letters,  numerals,  and  punctuation  marks.  One  font  is  10" 
high  for  names  of  featured  films  and  prominent  actors.  The 
other  is  4}^"  high  for  prepositions,  conjunctions,  and  an- 
nouncements of  secondary  importance. 

Many  more  molds  would  have  been  required  if  the  en- 


gineers had  not  arranged  cavities  for  certain  letters  and 
punctuation  marks  so  that  the  maximum  space  within  the 
mold  mounting  was  utilized.  As  it  was,  an  unusual  mold 
mounting  was  specially  constructed. 

Large  letters  and  numerals  are  shot  one  at  a  time,  ex- 
cept the  /  character,  two  of  which  are  produced  in  a  double 
cavity  die.  Hyphens  are  molded  alongside  the  letter  7. 
Commas  and  quotation  marks  are  of  identical  design,  as  one 
becomes  the  other  by  inverting  the  character  on  the  marquee 
rack.  Three  commas  (or  quotes)  and  one  period  are  molded 
in  a  single  shot. 

For  the  larger  set  of  characters  it  was  necessary  to  fabri- 
cate eight  numeral  molds  from  2  to  9.  The  7  letter  serves 
for  the  1  numeral  and  the  O  letter  for  the  0  numeral. 

Thus  35  cavities  were  machined  for  the  large  characters. 
Of  these  26  were  for  letters,  eight  for  numerals,  and  one  for 
punctuation  marks. 

Experience  in  designing  molds  for  the  large  alphabet 
helped  in  engineering  the  small  one.  In  one  form  five  small 
letters  are  cast  at  a  shot.  This  is  the  mold  which  contains 
the  letter  I,  since  it  occupies  a  small  space.  Except  those 
which  are  molded  with  punctuation  marks,  the  other  small 
letters  and  numerals  are  cast  four  in  a  die. 

Of  importance  equal  to  the  arrangement  of  cavities  was 
the  fabrication  of  a  master  mold  mounting  which  would  per- 
mit quick  changes  of  dies  and  cores  without  taking  the 
mounting  out  of  the  machine.  The  solution  arrived  at  pro- 
vides a  mounting  which  permits  changes  to  be  made  in  10 
min. 

These  rapid  changes  are  done  with  detachable  rails,  edges 
of  which  extend  inwards  to  clamp  the  cavities  and  cores. 


OCTOBER  1946 


PLASTICS 


21 


Die    with    49    cavities    injection    molds    six    eight  pan 
vinyl  assemblies,  each  a  component  lor  a  nasal  spray 


Cold  hall  ol  49-cavity  die.  with  raised  ejector  plate 
and   the  die's  41   ejector  pin*  in  advanced   position 

The  rails  arc  loosened  or  tightened  with  three  Allen  cap 
screws  mi  each  side  of  the  mounting.  Keyways,  cut  in  the 
flat  bed  of  the  mounting,  correspond  with  half-rods  ma- 
chined into  backs  of  cavities  and  cores  to  help  keep  the 
latter  in  position. 

Sometimes  1000  of  a  character  are  cast  at  OIK-  setting. 
Hut  .is  individual  letter  orders  seldom  run  into  so  large  a 
number,  the  ability  to  change  cavities  quickly  has  Woine 
an  important  factor  in  economical  production. 

With  the  wide  variety  of  -liajK-s  presented  by  the  letters, 
all  of  which  are  formed  in  the  same  master  mold  mounting. 
the  matter  of  ejecting  the  casts  was  solved  by  drilling  105 
elector  pin  holes  in  the  mounting.  Hy  this  device  it  merely 
is  in  .  •  ctor  pins  in  the  mounting  where 

they  Ix'-t  suit  the  s|ia|x-  of  the  ejector  plate  for  each  cavity. 
.  li\eness  of  the  design  and  readability  of  the  letters, 
coupled  with  the  glamor  imparted  by  cellulose  acetate  buty- 
ratc,  have  prompted  theater  operators  to  adopt  plastics  mar- 
quee characters  on  a  widespread  scale.  The  first  two  of  these 
influences  >tem  from  careful  designing.  They  didn't  iiM 
happen.  AS  the  cliaractrrs  were  to  IK-  backlighted  on  mar- 


Portions  ol  four-cavity  die  which  casts  ends  oi  fish- 
ing reel,  and  both  sides  ol  one  ol  the  ends  oi  reel 

ijuees,    the   effect   of   light    transmitted    through    tin 
colored  material  was  studied  exhaustively.    Numerous  trials 
of  the  material  in  the  form  of  sheets,  which  had  been 
different   treatments,   therefore   were  conducted. 

Out  of  this  research  was  develo|K-d  a  large  letter  shaded 
so  as  to  give  the  illusion  of  three  dimensions.  The  shading 
is  achieved  by  means  of  two  thicknesses  of  the  molde«: 
rial.  One  portion  ol  the  letter  is  '  *"  thick,  another  segment 
1/16"  thick.  It  was  deemed  inadvisable  to  shade  small 
letters,  lest  their  readability  IK'  reduced. 

Further  emphasis  is  giieii  shaded  areas  by  a  U-ad  molded 
at    the    separation    line    U-twcen    heavy    and    thin    sections. 
Heads  al-o  are  located  oil  both  large  and  small  cha- 
wherever    they    will    add    to    the    three-dimensional 
Edges  $i"  deep  are  molded  around  margins  of  all  cha- 
to  give  the  ap)K-arance  of  weight  ami  solidity 

Still  further  beauty  was  molded  into  ever)   ch.u.i.  • 
lightly  stippling  the  dies  with  a  hand  punch.      I  In-  tiealment 
imparted  a  frosted  effect,  which  causes  the  letters  to  sparkle 
like  radiant  jewels. 

1  abricatioii  of  molds  for  the  III"  ~ei  ies  ami  the  mounting 


11 


s 


(KTOBKK 


>r  all  the  characters,  including  machine  work  and  hand 
X)ling,  consumed  6500  man  hours.  The  cost  for  metal 
nd  time  was  approximately  $29,000.  The  same  work  for 
ie  4l/2r'  series  required  1100  man  hours  and  an  outlay  of 
5000.  With  these  molds  production  has  been  speeded  to 
5  shots  an  hour. 

Much  consideration  led  to  selection  of  Tenite  II  Formula 
18-A  for  this  undertaking.  It  was  apparent  that  the  letters, 
esides  transmitting  light,  had  to  have  high  resistance  to 
loisture  absorption,  temperature  extremes,  and  violet  ray 
ttack.  Further,  they  had  to  have  sufficient  impact  strength, 
theater  employees  often  drop  the  letters  from  step  ladder 
eight  to  the  sidewalk  while  changing  movie  titles. 

Another  motivating  factor  was  that  the  material  is  fur- 
ished  in  a  wide  color  range.  At  the  start  of  production  a 
rilliant  crimson  was -chosen  for  molding  all  the  characters, 
ilore  recently  the  firm  has  cast  numerous  alphabets  in 
merald. 

Lugs  in  the  form  of  hooks,  also  of  Tcnitc  II,  are  cemented 
i  slots  molded  on  backs  of  the  letters.  These  engage  a 
ellulose  acetate  butyrate  rack,  which  is  injection  molded 
or  installation  on  marquees.  Being  transparent  and  color- 
ess,  the  lugs  and  racks  transmit  light  without  casting  un- 
esirable  shadows.  The  union  of  lugs  and  letters  is  accom- 
lished  with  Tcnitc  II  No.  5575  cement  applied  by  dip  and 
rush. 


Reel  designed  for  the  surf  fisherman's  use  has  both 
ends  injection  molded  of  cellulose  acetate  butyrate 

Thread  on  the  inside  of  a  "Kodachrome"  slide  viewer 
neck  is  injection  molded  without  unscrewing  an  insert 


Two  types  of  lugs  are  fabricated.  Those  used  on  evenly 
balanced  letters  are  cast  in  a  24  cavity  mold.  For  the  letters 
F-J-I-L-P-T,  which  have  single  perpendicular  bars,  and  the 
unbalanced  figures  4-7,  a  special  lug  with  an  elongated  brac- 
ing elbow  is  provided.  This  special  brace,  which  is  as  long 
as  the  full  width  of  the  character,  prevents  unevenly  poised 
characters  from  leaning  out  of  position  when  on  display. 

To  expedite  marquee  changes,  frequently  used  words  are 
assembled  permanently  in  characters  from  the  4J4"  font. 
These  combinations  are  cemented  on  strips  of  clear  cellu- 
lose acetate  butyrate. 

Screw-Thread  Development 

While  the  firm's  theater  symbols  are  known  throughout 
the  country,  its  screw  thread,  made  without  unscrewing  a 
core,  is  so  new  that  it  is  in  use  on  only  a  few  products. 

This  development,  for  which  patent  has  been  applied,  pre- 
sents the  appearance  of  two  male  threads.  Molding  one  of 
these  on  the  external  portion  of  a  round  shape  presents  no 
problem.  The  other  thread,  molded  upon  the  inner  surface 
of  a  barrel,  involves  a  less  known  principle. 

Applied  to  the  interior  of  a  hollow  cylinder,  the  thread 
makes  less  than  one  circumference.  It  is  molded  at  the 
parting  line  of  the  cores.  Thus  the  method  of  production 
is  the  same  as  in  fabricating  an  internal  bead.  In  this  case, 
however,  it  is  a  severed  or  disjoined  bead,  the  two  ends  of 
which  curve  out  of  line  with  each  other. 

When  the  mold  opens,  the  cast  is  pushed  from  the  core 
by  the  ejector  stripper  ring  usually  employed  in  production 
of  barrel  shapes. 

Plastic  Die  &  Tool  has  used  this  thread  on  a  utility  dis- 
penser manufactured  under  the  firm's  trade  name  Durabrite. 
The  item  is  designed  for  hand  use  in  home  or  shop.  It 
either  pours  or  scatters  salt,  soda,  flour  or  other  powders. 

The  dispenser  is  molded  with  Tenite  II  in  three  parts — 
top,  barrel,  and  base.  The  base  and  barrel  are  fastened 
permanently  with  acetone  into  which  powdered  cellulose 
acetate  butyrate  has  been  mixed  to  establish  great  bonding 
power.  The  top,  which  is  removable  to  permit  loading,  is 
held  in  place  by  the  unusual  screw  thread. 

Because  the  dispenser  frequently  is  shaken  while  dis- 
charging contents,  threads  .05"  wide  and  .05"  deep  were 
molded  to  provide  a  strong  clamping  surface.  The  internal 
one  is  .025"  short  of  the  circumference  of  the  barrel  interior. 
Its  ends  are  tapered  slightly.  Thus  it  escapes  deformity 
when  the  barrel  is  ejected  from  the  mold.  It  closes  in  less 
than  one  complete  revolution. 

Machining  of  this  die,  which  included  milling  the  threads. 


Core  of  die  which  molds  internal  thread  on  utility  dispen- 
ser in  same  manner  as  that  of  Kodachrome  viewer  (left) 


Ejector  plates,  core*  and  cavities  used  in  the  injection  molding  of  small  and  large  letters  for  theater  marquees,  in  cellulose  acetate  butyrate 


took  900  man  hours.  Die  production  cost  amounted  to  $3700. 

Another  application  of  the  injection  molded  thread  \\a* 
in  a  Kodachrome  slide  viewer  fabricated  for  Chromato- 
scope  Co.,  Los  Angeles.  A  thread  1/16"  wide  and  .03"  deep 
runs  three  times  around  the  lens  barrel,  which  screws  into 
a  round  hole  on  the  top  of  a  box-like  structure.  Width  of 
this  thread  makes  for  quick  focusing. 

Inside  the  neck  of  the  box,  the  opposite  thread  resembles 
two  short  lugs,  one  molded  on  each  side  of  the  circular 
opening.  They  are  so  slanted  that  if  they  were  continued 
around  the  hole  they  would  form  a  complete  thread.  Again 
the  internal  threads  are  formed  at  the  parting  line  of  the 
mold  and  are  ejected  like  the  dispenser  barrel.  Tenite  II  in 
a  mahogany  tone  is  utilized  for  this  operation. 

Casting  of  the  slide  viewer  is  done  with  a  10  cavity  mold, 
which  produces  two  units  of  a  five  part  assembly  at  a  shot. 
Fabrication  time  of  the  die  was  nearly  1000  man  hours.  Cost 
was  approximately  $4000. 

Knds  of  a  surf  casting  fishing  reel,  made  of  transparent 
red  Tenite  II  for  Aerco  Corp.,  Hollydale.  Calif.,  presented 
a  variety  of  interesting  problems.  Mountings  for  the  gear 
train  had  to  be  held  to  close  tolerances.  Yet  the  original 
pattern  had  several  thickne**c*,  which  would  cure  at  an 
uneven  rate.  The  driving  end  of  the  reel  had  six  cored 
hole*,  three  recessed  holes,  and  two  metal  insert*  for  drive 
k'-Mr  -.  The  opposite  end  had  two  cored  holes,  eight  m  • 
hole*.  .in<l  OIK-  metal  insert.  To  add  further  complication*. 
•  ral  build-ups  were  nece**ary  to  provide  clearance. 

F.nginecr*  of  Pla*tic  Die  &  Trxil  met  the*e  probK-m*  l>\ 
•j;ning  cross  sectional  thicknc**e*  of  both  parts  to  bring 
them  into  a*  close  uniformity  a*  pn**ible.  My  -o  doing  the 
shrinkage  expected  in  molding  could  IK-  calculated  ac- 
curately and  allowance*  made  in  machining  the  cavitie*. 
However,  a*  few  liln-rties  as  possible  were  taken  in  dc*ign 
change*,  a*  the  end*  hail  to  lit  gear  train*  which  already  had 
Ix-en  fabricated.  ()bviou*ly  no  changes  could  IK-  made  in 
position  or  type  of  hole*  and  in 


24 


Although  six  critically  positioned  metal  inserts  had  to  be 
loaded  for  each  shot,  a  four  cavity  die  to  cast  two  units  of 
two  parts  was  machined.  To  prevent  deforming  the  part*, 
six  ejector  pins  were  used  for  the  driving  ends  and  five  for 
the  reverse  ends. 

Fabrication  of  the  die  required  800  man  hours.  The  co*t 
in  engineering,  metal,  and  workmanship  was  slightly  in  ex- 
cess of  $3200.  Despite  time  for  loading  inserts,  production 
of  the  reel  ends  now  is  proceeding  at  the  rate  of  55  shot*,  or 
220  parts,  an  hour. 

Speeding  Production  with  Multiple  Cavity  Dies 

To  meet  competition  by  increasing  production  speeds,  this 
firm  recently  has  fabricated  several  multiple  cavity  dies 
which  have  distinguished  themselves  by  unusual  perform- 
ances. One  of  these,  a  mold  to  produce  some  of  the  com- 
ponents of  a  new  type  nasal  sprayer,  the  Jetomuer,  for  I'al- 
mar  Co.,  Los  Angeles,  has  49  cavities. 

This  multiple  cavity  die  forms  six  complete  units  of  an 
eight  part  assembly.  It  also  molds  one  additional  valve 
seat,  '/£"  in  diameter  and  5/16"  in  length,  which  is  in  ex  cry 
unit.  Fabricators  foresaw  that  this  valve  seat.  U-cau 
very  small,  frequently  would  disappear  in  the  assembling 
process.  Hence  the  extra  part  is  molded  with  each  *hot  to 
cover  the  incidence  of  lo**. 

As  the  parts  are  those  which  form  ami  direct  the  s| 
the  job  obviously  had  to  be  a  precision  operation.     '1  he 
danger  of  distortion  in  ejecting  so  many  *mall  part- 
one  mold  wa*  very  great.     Therefore  41   ejector  pin*  \\ere 
built  into  the  die.     In  addition  an  automatic  ejecto: 
xxa*  m*tallcd  to  cli*plarc  24  of  the  smaller  piece-.     The  mold 
also  has  a  coring   mcchani*in   on   the   end*   of   \\hich   are 
needlelike  |>oint*  to  e*tabli*h  spray  hole*  in  the  no//]e*. 

Despite  the  many  intricacie*.  the  die  wa*  producer 
of  $6,450  in  slightly  le**  than  l.W  man  hour*. 

lloxxever,   another   precaution   \\a*   adopted    to   hold   the. 
minute  part*  to  .IHl.V  tolerance*.     Thi*  XN.I*  the  lunl'l 

•  •ntinurd  on  page  100) 


(HTOBKK  1916 


Airplane  control  wheels  dip/ted  in  Tenite  gel  lacquer  by  Scott  Aviation  Corp. 

Tenite  Gel  Lacquer  Coats  Airplane  Control  Wheels 


I'luin   imutli'ii    titiil  liantllf   (left)  gets   thick 
plastic  coating  ii-ith  Tcnitffifl  lacquer  (right). 


A  few  dips  in  Tenite  gel  lacquer 
produced  the  hard,  lustrous,  touch- 
pleasant  surface  of  these  airplane 
control  wheels.  The  lacquer,  made 
by  dissolving  Tenite  pellets  of  the 
desired  color  and  opacity  in  suit- 
able solvents,  provides  the  alumi- 
num castings  of  the  wheels  with  an 
economical  finish  much  thicker 
than  can  be  obtained  by  the  same 
number  of  dips  in  ordinary  lacquers. 

Tenite  gel-lacquer  coatings  are 
continuous,  with  complete  absence 
of  the  parting  line  which  appears 
on  molded  products.  They  may  be 


applied  to  wood  as  well  as  to  metal, 
and  to  certain  plastics,  including 
articles  molded  from  scrap  of  mixed 
colors.  Among  the  products  which 
can  be  coated  are  handles  of  kitch- 
en utensils  and  tools,  towel  bars, 
and  long  bars  which  are  beyond  the 
capacity  of  a  machine  for  covering 
by  injection  molding. 

For  information  concerning  the 
preparation  of  gel  lacquer  from 
Tenite  pellets,  write  to  TENNESSEE 
EASTMAN  CORPORATION  (Subsidi- 
ary of  Eastman  Kodak  Company), 
KINGSPORT,  TENNESSEE. 


TENITE    AN   EASTMAN  PLASTIC 


Granular  polyethylene  which  is  being  placed  into  hopper  is 
picked  up  by  sprue  which  passes  it  through  machine  and  also 
heats  it.  Die  at  end  of  machine  regulates  size  and  shape  of 
finished  product.  Right,  another  view  of  completed  cable 
coming  out  ol  the  extruder  on  its  way  to  the  cooling  bath 


Insulating 

High  Frequency  Cables 


'u   r^inalana     lll[.  ^J\rueqer  ana    L^arl  _Xr. 

Dir.    of    Research  Mgr.    Synthetics    Div. 

American   Phenolic  Corporation 


IN  RADIO,  radar  and  television,  in  the  broadcasting, 
transportation  and  communications  fields,  wherever 
electronics  are  used,  plastics  dielectric  cables  are  giving 
excellent  service  in  a  hundred-and-one  high  frequency  appli- 
cations. 

Shortly  before  1937,  engineers  foresaw  a  rapid  expansion 
in  the  field  of  electronics.  The  war  greatly  accelerated  this 
advancing  trend  and  made  imperative  the  immediate  produc- 
tion of  vast  quantities  of  flexible  cable  and  component-  to 
supply  urgent  military  and  naval  requirements.  The  im- 
provement of  manufacturing  techniques  and  wider  applica- 
tion became  one  of  the  most  important  phases  of  electronics 
re-earch. 

1-ortunately,  the  steady  improvement  in  the  production 
and  use  of  high  frequency  cable  which  took  place  during  the 
war  years  could  IK-  instantly  converted  to  the  servicing  of 
the  needs  of  industry  once  peace  came,  anil  the  extensive 
array  of  electronic  device-,  and  applications  restricted  to  \\ar 
11  i  have  now  been  released  for  unrestricted  commercial 
<  •\ploitation. 

Back  in  1W7,  the  engineering  and  fabrication  departments 
of  the  American  Phenolic  <  orporation  (  Ainphenol  )  intro- 
duced one  of  the  very  first  plastics  high  frcqcncy  cables. 
Ibis  was  the  |H>lvstyrcnc  U-aded  cable,  and  its  ingenious 
"beaded"  construction  wa-  a  radical  improvement  over  any 
similar  product  available  at  that  time.  The  Ix-ad-  were  mold 


ed  from  pure,  transparent  polystyrene.     The  cable  had 
cellent  dielectric  properties,  could  be  bent  on  a  short  ra< 
and  operated  safely  at  temperatures  up  to  190°F.    The  01 
standing  advantage  of  this  cable  was  that  because  the  e 
trical  field  lay  entirely  between  two  conductors,  radial 
«as  practically  eliminated.    Then.  too.  surrounding  objec 
such  as  large  masses  of  metal,  had  no  effect  on  t! 
line  and  there  was  no  pick-up  of  spurious  current-,  -ncl 
static  or  radiations,  from  other  electrical  circuit-. 

For  a   good   many   uses,   where   low    capacity   and   h 
efficiency  are  required,  polystyrene  beaded  cable  i-  excellenl 
Such  present-day  low  capacity  applications  as  photo  , 
cells  and  photostat  tubes,  for  example,  use  beaded  call 
This  type  of  cable  is  not  practical  for  some  Use-,  li. 
In-cause   the  air   |x>ckets   In-twecn   the   "In-. id-"   |x-rmit  CO 
densation  under  certain  conditions.     In  the  ca-e  of  aircra 
for  instance,  tcm|xTatnre  variations  would  permit  nioi-u 
to  collect  in  these  |«K'ket-  anil  thus  effect  a  short  circuit. 

\-  a  rc-ult  nl   this  additional  need,  a  new   cable,  a  SO 
dielectric  co|x>lenc  cable,  which  excluded  these  .111 
was  developed,    t  opolcne  is  a  copolymer  of  polyisobrityleOJ 
It  has  extremely  low -loss  dielectric  characteristics  and   il 
many  other  ways  its  dielectric  qualities  are  -imilar  t. 
nl  polystyrene.     It  i-  al-o  an  outstanding  cable.  IK-C.; 
its  mechanical  ruggrdtn  '-in  from  moisture  ab-orp 

lion,  and  improved  termination  in  assembling,  mounting  am 


I*I..\STI<-S 


(KTOKKK  1941 


connecting.  This  cable  offers  a  wide  variety  of  uses  in 
equipment  built  for  high  frequency  or  microwave  operation, 
such  as  is  required  for  television,  frequency  modulation,  test 
equipment,  lead-in  transmission  lines  of  standard  broadcast 
installations  and  many  other  applications. 

But  undoubtedly  one  of  the  most  highly  perfected  cables 
in  use  today  is  the  polyethylene  dielectric  cable.  Polyethy- 
lene has  many  outstanding  characteristics  and  advantages 
not  possessed  by  polystyrene  and  copolene.  This  cable  per- 
mits the  maximum  utilization  of  polyethylene's  dielectric 
qualities.  Its  bending  radius  is  ten  times  the  outside  cable 
diameter  and  may  be  maintained  over  a  wide  range  of 
temperatures.  Polyethylene  is  readily  extruded  to  form  a 
solid,  flexible  cable  dielectric  of  low  moisture  absorption. 
The  cable's  tough,  resilient  plastics  vinyl  'outer  jacket  is 
highly  practical  and,  of  course,  meets  A-N  requirements 
and  specifications.  This  outer  vinyl  jacket  is  characterized 
by  its  low  water  absorption,  and  it  is  totally  unaffected  by 
exposure  to  or  contact  with  alkalis,  acids,  oils  or  gasoline. 

Few  manufactured  products  are  subject  to  the  elaborate 
and  extensive  tests  through  which  polyethylene  dielectric 
cable  is  put,  in  order  to  insure  its  uniform  quality  and  per- 
formance. Strict  end-to-end  uniformity  is  maintained 
throughout  the  entire  manufacturing  process.  This  is 
accomplished  by  precision  extrusion,  accurate  temperature 
control,  constant  process  inspection  and  micrometer  gauging 
standards. 

The  wires  used  in  most  polyethylene  cables  are  copper, 
although  frequently,  where  additional  strength  is  required, 
copper  clad  steel  is  employed.  Frequently,  too,  tinned  and 
silver  coated  copper  wires  are  used.  Whatever  the  metal 
used,  however,  the  process  of  extruding  the  polyethylene 
over  the  wire  is  similar.  Standard  extruding  machines  are 
employed,  but  great  care  is  taken  to  make  certain  that  over- 
all dimensions  and  the  centering  of  the  electric  conductor 
are  maintained  within  a  predetermined  range  of  ±  .005  to 
.0005".  The  cable  is  put  on  reels  as  it  comes  from  the 
extruding  machines,  and  automatic  rolling  micrometers  keep 
constant  vigil  on  the  tolerance  of  the  cable,  coincidental 
with  the  extruding  process. 

The  next  step  in  the  production  of  polyethylene  dielectric 
cable  is  the  braiding  or  weaving  of  a  copper  wire  over  the 
dielectric,  in  order  to  form  a  return  circuit.  And  after  this 
has  been  done,  a  jacket  is  placed  on  the  cable.  This  is 
usually  of  vinyl,  but  it  is  frequently  polyethylene ;  in  either 
case,  it  is  extruded  over  the  braiding.  Sometimes,  where 
weather  resistance  is  not  important  and  the  cable  is  to  be 
used  for  interior  applications  with  no  danger  of  moisture 
penetration,  a  cotton  jacket  is  applied  by  means  of  a  process 
similar  to  wire  braiding.  The  cable  is  then  ready  for 
shipment. 

From  the  very  first  extruding  process  through  the  jacket- 
ing of  the  cable,  when  it  is  ready  to  go  to  the  customer,  poly- 
ethylene cable  is  subjected  to  18  different  tests  and  to  the 
most  demanding  conditions  it  could  meet  in  actual  use. 
Every  5,000  feet  of  the  cable  is  checked  at  every  step  in  its 
manufacture  to  guarantee  uniform  and  accurate  fabrication. 
Performance  ratings  and  extensive  repeated  testing  checks 
such  important  factors  as  proper  size  and  quality  of  inner 
conductors,  accuracy  of  dielectric  O.D.,  absence  of  voids  in 
dielectric,  close  centering  of  inner  conductor,  proper  size 
and  quality  of  braided  shielding,  correct  overall  O.D.,  close 
centering  of  outer  jacket  and  proper  cable  markings.  . 

These  tests  are  made  in  the  laboratory  on  random  samples 
of  cable,  and  similar  tests  and  controls  are  used  throughout 
the  various  processes.  The  cable  is  further  checked  for  such 
important  quality  factors  as  nominal  impedance,  velocity  of 
propagation,  attenuation  at  ultra  high  frequency,  nominal 
capacitance,  low  capacitance  unbalance,  absence  of  cracks 
and  fractures  of  dielectric  on  cold  bend  test,  close  centering, 
(Continued  on  page  99) 


Continuous  rolling  micrometer  constantly  gauges  the 
high  frequency  cable  to  assure  accurate  dimensions 


Cable  is  placed  over  arbor  ten  times  its  diameter 
with  weight  on  each  end  to  determine  heat  stability. 
Below,  constant  testing  oi  electrical  properties  of 
the  finished  cable  assembly  assures  high  quality 


OCTOBER  1946 


27 


Shaver  Holder 
Uses  Plastics 

JVew  accessory  is  decorative, 
compact  and  simple  in  design 


An  exploded  view  ol  the  new  "Plaslcon" 
streamlined  holder  shows  its  various 
molded  components:  the  case,  frame, 
latch,  switch  pin.  spool  and  ratchet 


; 


:*      /-' 


Designed  by  Raymond 
Loewy  Associates  to  har- 
monize in  line  and  color  with 
the  latest  Schick  models, 
the  new  Shaverest  is  formed 
to  accommodate  any  Schick 
Shaver  regardless  ol  age 


HAVINd  used  plastics  with  outstanding  success  in  its 
electric  shaver.  Schick,  Inc.,  repeated  itself  once  more 
when  it  developed  an  entirely  new  product — the  "Shaverest." 
a  recently-marketed  device  for  mounting  the  shaver  per- 
manently and  conveniently  in  the  bathroom.  Again,  having 
found,  in  the  development  of  the  shaver,  that  close  collabo- 
ration In-tween  itself,  the  molder,  and  designer  was  invalu- 
able (see  "The  Schick  Shaver — A  Case  History,"  p/off/c», 
April,  1946),  the  company  has  followed  the  same  procedure 
with  the  Shaverest. 

The  designers  who  fashioned  the  Schick  Super  and  Col- 
onel modi-Is,  Raymond  I^oewy  Associates,  were  called  in  to 
work  out  the  styling  of  the  Shave-rest.  The  first  condition 
that  influenced  their  thinking  was  that  the  product  wa-  es- 
sentially an  accessory  to  the  shaver  and  not  an  independent 
article.  Its  size,  shape,  decorative  motifs  and  functional 
structure  were  therefore  determined  by  the  shaver.  Since 
the  must  logical  place  to  keep  a  shaver  within  reach  and 
reaih  for  use  at  all  time^,  is  the  bathroom  wall  near  the 
mirror,  the  Shaverest  was  styled  as  an  appropriate  bath- 
room fixture  with  this  location  in  mind.  Simplicity,  com- 
pactness, and  ea-e  of  maintenance  were  primary  design 
consideration-.. 

Aiming  that  the  Slum-rest  would  lie  N>ught  by  owner^ 
of  a  Si-hick  shaver,  it  was  designed  to  harmoiii/e  in  line 
ami  color  with  the  latent  SII|RT  and  Colonel  model-.  At  tin- 


same  time,  it  was  formed  to  accommodate  any  Schick  shaver 
regardless  of  age.  The  holder  is  molded  of  ivory  I'laskon 
urea  formaldehyde,  with  touches  of  maroon  for  the  auto- 
matic current  and  cord  control  buttons.  ( >rnamental  grooves 
and  other  decoration  have  been  eliminated  to  simplify  the 
problem  of  keeping  the  stationary  wall-rest  clean.  Two 
flanges  or  arms  molded  to  complement  the  contours  of  the 
shaver  form  the  cradle.  Not  only  does  this  form  secure  the 
shaver  in  the  holder,  but  it  also  makes  possible  cftortles* 
removal  at  all  times. 

Easily  Installed 

Installation  is  a  simple  matter,  the  Shaverest  ln-ing 
designed  with  slats  which  lit  a  fixed  wall  spring  bracket. 
Although  the  union  i-  secure,  the  Shaverest  can  be  renuncd 
from  the  wall  bracket  easily. 

The  40-inch  plug-in  retractable  cord  for  the  sha\ei  i- 
\\ounil  upon  a  reel  concealed  within  the  Shaverest.  thcteln 
eliminating  a  loose  dangling  cord  which  would  have  to  U- 
wound  by  hand  before  and  after  using  the  Shaver.  Another 
advantage  of  tin-  safe  reeling  method  is  the  protection  al- 
fordcil  to  the  plug  and  cord  union.  With  a  slight  pull,  the 
cord  can  IK-  drawn  out  to  the  desired  length  and  held  there 
by  a  trigger  Mop.  After  shaving,  tin-  cord  is  reeled  ii|> 
automatically  at  a  touch  of  the  cord  control  button  on  the 
side  of  the  Sh.iM-re-i  I  he  cord  is  plugged  in  at  all  times, 


I'l.ASTH  s 


(HTOHKR 


p 


"Robots  At  Work"  is  a  30-minute  color 
and  sound  16  mm.  motion  picture  photo- 
graphed in  full  color  Kodachrome,  with 
narration  by  Lowell  Thomas.  It  had  its 
premier  at  the  National  Plastics  Exposi- 
tion in  New  York— has  been  previewed 
by  only  a  few  selected  groups. 

This  film  tells  the  story  of  compression 
molding,  from  hand  to  completely  auto- 
matic production  methods.  It  shows  typi- 
cal pieces  and  cost  studies  on  parts  suit- 
able for  automatic  molding — points  out 
why  and  when  this  is  the  most  economical 
method  for  molding  many  different  parts. 
It  shows  automatic  closure  presses  pro- 
ducing thousands  of  bottle  caps  per  hour. 
Installation  "shots,"  equally  impressive, 
are  shown  from  various  plants. 

"Robots  At  Work"  is  new,  colorful,  in- 
structive, entertaining — and  prints  are 
now  available,  loaned  for  showing  be- 
fore company  groups,  technical  societies, 
engineering  schools  and  colleges. 

T&tOe  £>*  *  foe&Mf  and  please  give  a 
choice  of  two  or  three  dates  if  possible. 

F.  J.  STOKES  MACHINE  COMPANY 

6040  Tabor   Road,  Philadelphia  20,  Pa. 


COMPLETELY  AUTOMATIC 
PLASTICS  MOLDING 


•  NEW  30-MINUTE  16  MM.  SOUND  FILM 

•  IN  BRILLIANT  KODACHROME 

•  NARRATED  BY  LOWELL  THOMAS 


MOLDING  EQUIPMENT 


Eft 


"Ploskon"  Shaverest  case*  are  molded  in  a  4-cavity  compres- 
sion mold.  Note  thinness  of  flash  at  bottom  of  cradle  in 
case  at  extreme  left.  (Right)  frames  in  center  are  ready  to 
be  taken  from  mold  and  placed  in  cooling  fixture  at  left 


and  the  electric  current  is  turned  on  as  the  button  is  re- 
lieved of  the  weight  of  the  shaver.  When  the  shaver  is 
replaced,  the  current  is  cut  off  immediately. 

Beyond  its  advantages  in  protecting  the  shaver,  in  con- 
serving shelf  space,  and  in  housing  the  shaver  in  a  conven- 
ient location,  it  is  a  decorative  addition  to  the  bathroom. 

While  the  Shaverest  was  in  process  of  designing,  suc- 
cessive drawings  were  shown  to  Plastic  Manufacturers,  Inc., 
of  Stamford,  Conn.,  the  molding  company  which  was  going 
to  produce  the  unit.  When  the  final  three-dimensional  plas- 
tilene  model  was  made,  that,  too,  was  submitted  to  the 
molder  for  suggestions  which  might  facilitate  production 
of  the  finished  article.  This  consultation  proved  fully  fruit- 
ful, according  to  executives  of  Plastic  Manufacturers,  Inc., 
who  provided  the  following  data  on  the  molding  techniques 
which  were  used. 

The  Shaverest  is  made  up  of  six  molded  parts:  case, 
frame,  spool,  ratchet,  latch  and  switch  pin.  The  case,  as 
stated  above,  is  made  from  urea  formaldehyde  and  is  molded 
in  a  four-cavity  compression  mold  on  a  350-ton  press  which 
has  a  line  pressure  of  1000  psi,  and  two  pills  are  placed  in 
each  cavity  after  being  electronically  preheated  in  a  Thermal 
unit. 

The  inside  of  the  cradle  is  molded  by  using  a  loose  mold 
part.  Since  the  Schick  name  had  to  be  placed  on  the  top 
edge,  it  was  necessary  to  have  the  mold  section  continue  up 
around  the  edge  of  the  piece.  This  loose  mold  section  is  at- 
tached to  the  ejector  pins  and  stays  in  the  mold  at  all  times. 
In  operation,  these  loose  sections  are  forced  up  by  the  ejec- 
tor pins,  thus  raising  the  molded  parts  out  of  the  cavity. 
These  parts  are  then  easily  pulled  off  by  hand.  The  oper- 
ating temperature  of  the  die  is  maintained  between  280° 
and  290°  F. 

Removal  of  Flash 

The  flash  around  the  outer  periphery  of  the  part  is  eas- 
ily removed  at  the  press,  leaving  the  flash  around  the  cradle 
to  be  removed  by  a  rotary  file.  The  flash  from  the  hole  in 
the  top  and  the  slots  in  the  skirts  is  later  removed. 

The  frank-  is  also  molded  of  urea,  on  a  500-ton  semi- 
automatic transfer  press.  The  mold  is  a  four-cavity  plunger 
type,  and  a  temperature  of  280°-290°  F  is  maintained. 
Transfer  pressure  on  the  material  is  about  11,000  psi.  The 
Mash  around  the  outer  edge  is  easily  removed  at  the  press, 
and  the  gate  is  later  removed  by  sanding.  There  is  very 
little  other  Mash  to  be  removed. 

After  these  parts  are  removed  from  the  press,  they  are 
put  in  a  special  cooling  fixture,  designed  by  the  inoldets. 


in   which  the  parts  are  held  in  place  by  the  air  pressure. 

As  anticipated  on  this  part,  transfer  flow  of  the  tire. 

a  problem,  but  it  was  easily  solved  by  a  socialized  technique. 

This  part  lent  itself  very  well  to  transfer  molding  be- 
cause of  its  shape  and  the  large  number  of  small,  cored-nut 
blind  holes.  It  was  originally  designed  with  serratimis 
around  the  outer  edge,  but  these  were  omitted  to  allow  for 
greater  ease  in  molding  and  Iwcausc  it  was  felt  that  the 
serrations  would  catch  dirt  after  the  Shaverest  was  mounted 
on  the  wall.  To  avoid  warpage.  additional  draft  was  added  to 
some  surfaces.  Electronically  heated  preforms  are  :iK 
in  molding  this  part. 

The  switch  pin  is  made  on  an  eight-cavity  plunger  type 
mold  on  a  50-ton  semi-automatic  transfer  press.  The  mate- 
rial, a  maroon-colored  phenolic,  is  automatically  pre- 
formed and  electronically  preheated  before  it  is  placed  in 
the  pot.  The  transfer  pressure  on  the  material  is  6000  psi, 
and  the  die  is  maintained  at  a  temperature  of  about  330°  F. 

The  gates  on  this  pin  are  so  small  that  the  parts  can  be 
broken  off  from  the  runners  at  the  press,  and  the  only  addi- 
tional operation  required  is  tumbling  to  remove  the  flash. 

Because  of  the  customer's  desire  to  have  the  rounded  end 
of  this  pin  free  of  any  mark-,  the  mold  was  originally 
designed  with  the  ejector  pins  under  the  runners  only. 
While  this  method  was  satisfactory  for  ejecting  the  part, 
it  was  found  that  vents  had  to  be  added  to  the  bottom  of  the 
cavities  because  the  parts  had  burnt  spots  due  to  trapped 
gases.  Since  this  was  more  or  less  anticipated,  it  was  a 
simple  matter  to  add  ejector  pins  in  the  bottom  of  the  cax  ity 
which  could  act  as  vents. 

The  spool  is  plunger  molded  on  a  four-cavity  mold  on  a 
50-ton  semi-automatic  transfer  press.  The  molding  com- 
pound is  a  brown  phenolic  which,  again,  is  automatically 
preformed  and  electronically  preheated.  Here,  too,  the  gate 
is  so  small  that  it  can  be  broken  off  at  the  machine,  and  the 
only  other  finishing  required  is  tumbling  to  remove  the  flash. 
To  eliminate  warpage,  the  pieces  are  placed  in  the  cooling 
fixture  at  the  machine. 

The  ratchet  is  similar  to  the  spool  and  is  asscniM< 
it  by  self-tapping  screws  to  form  the  complete  reel  assem- 
bly.  It  is  molded  and  finished  in  the  same  way  as  the  s|x>ol. 
The  material  used  is  a  phenolic  grade  with  greater  strength. 

Finally,  there  is  the  latch,  which  is  run  on  an  eight-- 
plunger type  mold  on  a  50-ton  semi-automatic  transfei 
The  molding  operation  is  similar  to  that  used  in  making 
the  spool.   Here  again  the  gates  arc  so  small  and  are  !• 
in  such  a  place  that  the  parts  ran  IK-  broken  oil"  the  runners 
at  the  machine  and  then  tumbled  t"  rem-ixe  the  flash.      i  M> 


30 


r  i.  AST  ic  s 


(MTOKKK   n 


mai troll    makes 


SEAMS 


on  products  like  these 


STRONG  AS  MATERIAL  ITSELF" 


".  .  .  since  they  are  fabricated  by  elec- 
tronic heat  sealing,  they  are  extremely 
durable  ,  .  .  their  welded  pressuretight 
seams  are  as  strong  as  the  plastic  mate- 
rial itself  . . ." 

-Bakelite  Review,  July,  1946. 


IHERMATRON  sealing  makes  the  seams  in  these  fast-selling 
beach  toys  air-tight,  water-tight— and  as  strong  as  the  durable 
plastic  of  which  they're  made. 

THERMATRON  replaces  stitching  . . .  eliminates  adhesives  and 
solvents  .  .  .  increases  the  product's  tensile  strength.  THERMA- 
TRON bonds  dissimilar  materials,  too.  THERMATRON  electronic 
sealing  is  the  fast  low-cost,  modern  way  to  seal  and  seam  hand- 
bags, cushions,  mattresses,  shower  curtains,  garment  bags, 
beach  toys,  raincoats,  shoes  and  many  other  fabricated  plastic 
products.  Literally  hundreds  of  fast-selling  new  plastic  and  ply- 
wood products  have  been  made  possible  by  THERMATRON. 

In  plastic  molding,  THERMATRON  decreases  curing  cycle  50  to 
75%,  cuts  costs  way  down  . .  .  prolongs  mold  life,  assures  better 
cure,  less  internal  stress,  uniform  density  and  high  gloss  without 
blistering  and  flow  marks.  High  paid;  highly  trained  operators 
are  not  required  for  THERMATRON. 

Find  out  for  yourself  what  THERMATRON  can  do  for  YOU. 
See  our  new  8-page  booklet,  "Electronic  Heating  and  Sealing 
With  the  THERMATRON",  which  illustrates  and  describes  the 
use  of  industrial  electronic  heat  generators  for  the  preheating 
and  sealing  of  plastics,  plywood  and  various  other  dielectric 
_^^^  materials.  Described  in  detail  are  several 

—       ^m     ^^^^^^^         types   of  standard   THERMATRON   elec- 
^^1  ^^        tronic  equipment,  complete  with  ovens 

l^fl  and  presses  now  being  used  on  the  pro- 

duction line  and  in  the  laboratory-  Write 
on  your  letter-head  for  your  copy  of 
•       "Electronic  Heating  and  Sealing  With  the 
THERMATRON"  today. 

Thermalron  feam:  water-tight.  Address  Dept.  T—  16 

air-tight— and  quicker  to  make. 


Stitched  teams  puncture  material, 
decreaie   product  strength. 


•  ti4vriiirfl.ro.nl      DIVISION 

RADIO  RECEPTOR  COMPANY,  INC. 

Since  1922  in  Radio  and  E/ecfronics 

251  West  19th  Street    /£$\    New  York  11,  N.Y. 


Midwest  Sales  &  Service:  Zephyr  Electronics,  Chicago 


'OCTOBER  1946 


PLASTICS 


31 


Thirty  heated  punches  oi  die  soften  spots  on  grille  and  flow  plastics,  fastening  wire  screen  securely 

Special  Fixtures  Speed 


J4erl>ert   Ck 


aJ<? 


Post-Mold 


Cemented  gear  shift  knobs,  set  on  a  rotating  drum, 
pass  under  belt  applying  pressure  while  cement  sets 


IT  IS  commonly  ^'ii<l  that,  when  plastics  moldings  come 
from  the  mold,  they  are  practically  ready  for  use.  But 
the  tjualifying  word  practically  ran-ly  receives  much  empha- 
sis. Moldcrs  arc  well  aware  that  Hash  or  runner-,  always 
have  to  be  removed  and  that  there  is  often  one  or  more 
other  operations  to  perform  In-fore  moldings  are  usable.  In 
fact,  many  plants  devote  as  much  space  to  finishing  opera- 
tions as  for  making  the  moldings,  if  not  more. 

In  the  molding  department  at  the  Ford  River  Rouge  plant 
there  is  ample  proof  of  this  statement.  A  large  area  is 
devoted  to  finishing  o|K-ratioiis  on  the  moldings  produced 
in  some  forty  presses  arid  twenty  injection  molding  machines. 
as  described  in  plottlct.  September,  1946.  Press  operators 
often  perform  a  part  of  the  cleaning  but  rarely  have  time 
to  do  it  all  and,  as  a  rule,  do  not  operate  machines  other 
than  molding  machines. 

I'lastics  molding-  u-ed  in  I-ord.  Mercury  and  Lincoln 
ignition  systems  require,  in  many  cases,  not  only  removal 
of  flash  but  other  machine  operations.  Most  (,f  the  machi- 
ning is  (|uite  simple  and  is  usually  done  with  standard  ma- 
chine tools.  Such  work  is  not  described  here.  Considera- 
tion is  centered  in  this  article  upon  operations  on  injection 


32 


(MTOKKK 


Hood  pull  handles  move  around  dial  as  three  wheels  set 
at  various  angles  remove  flash,  polish  exposed  surfaces 


Machining 


moldings   that   will   fulfill   both   functional   and   decorative 
purposes. 

Generally  cut  from  runners  by  molding  machine  opera- 
tors, these  injection  moldings  are  sometimes  usable  imme- 
diately, but  many  require  debossing  of  letters,  polishing,  or 
other  finishing  operations,  and  still  others  have  to  be  as- 
sembled to  mating  parts  of  plastics  or  metal. 

A  typical  example  is  the  "stamping"  (debossing)  of  the 
name  Ford  on  molded  acetate-butyrate  horn  buttons.  This 
is  done  in  a  press  equipped  with  an  electrically  heated 
punch  and  a  dial  fixture.  A  ribbon  of  cellophane  coated 
with  a  pigmented  plastics  composition  in  a  color  that  con- 
trasts with  that  of  the  button  is  arranged  tor  automatic 
feed  below  the  punch.  As  the  latter  is  lowered,  it  presses 
the  ribbon  into  the  molding.  That  portion  of  the  ribbon 
gripped  between  the  punch  and  the  molding  adheres  to  the 
recess  formed  by  the  punch  letters  and  sticks  to  the  molding 
in  the  depressions.  The  remainder  of  the  ribbon  feeds  out 
and  is  scrapped. 

This  machine  operates  automatically  except  for  loading 
and  unloading  the  buttons  (or  knobs,  which  are  done  in 
the  same  way  but  with  a  different  dial  fixture  made  to  fit 
them )  by  the  operator.  He  merely  places  the  buttons  on 
the  individual  fixtures  attached  to  the  dial,  which  indexes 
around  past  the  punch  and  returns  the  marked  moldings  to 
the  unloading  position.  The  operator's  hands  are  well  away 
from  the  punch  and  he  does  not  have  to  watch  it,  as  both 
dial  and  punch  motions  are  automatic  and  positively  syn- 
chronized. Up  to  1000  parts  an  hour  are  handled  through 
this  machine. 

Hood  pull  handles,  produced  in  16-cavity  molds,  are  cut 
from  gates  by  the  molding  machine  operator  but,  to  remove 
any  light  flash  along  the  parting  line  and  to  improve  surface 
finish  by  polishing,  the  moldings  are  fed  through  a  Ham- 
mond polisher.  On  the  bed  of  this  machine  is  a  dial  with 
seven  heads  that  turn  slowly  about  their  own  axes  as  the 
dial  carries  them  around  under  three  wheels  set  to  polish 
all  surfaces  of  the  moldings. 

All  the  operator  does  is  to  load  and  unload  the  parts  which 
fit  over  spindles.  This  is  done  well  away  from  the  wheels, 
and  all  dust  is  drawn  off  through  hoods  that  fit  over  half 
of  each  wheel.  About  30  pieces  a  minute  are  polished  on 
this  machine. 

Subsequently,  the  handles  are  fed  through  a  fixture  in 


Press  with  indexing  drum  fixture  and  side  recesses  for  hood  pull   handles  forces  metal  shanks  into  cored  holes.     Right, 
dial  fixture  passes  horn  buttons  under  a  heated  stamp   above  a  plastics  ribbon,   where   "Ford"  trademark  is  imprinted 


The  press   ram  forces  metal   ring   bushings  into   ventilator 
handle  escutcheons  after  molding  and  ring  are  set  by  hand 

a  light  press  for  insertion  of  ;i  plated  steel  shank.  Kach 
shank  has  the  inserted  end  grooved  circuniferentially  in 
such  a  way  that  sharp  edges  prevent  the  shank  from  pulling 
out.  The  shanks  could  be  molded  into  the  pull  handle  hut 
this  would  slow  the  molding  cycle  greatly  and  is  done  much 
more  rapidly  in  the  fixture. 

Each  molding  is  placed  in  a  side  socket  of  an  index  in;; 
drum  and  a  shank  is  inserted  in  a  slot  above  the  molding. 
As  the  parts  are  indexed  under  the  press  ram.  it  lowers 
automatically  and  presses  the  shank  home.  Again,  the 
operator  does  only  loading  and  unloading  and  works  with 
his  hands  well  away  from  the  punch  so  that  there  is  no 
accident  hazard.  Parts  are  run  through  a*  fast  as  they 
can  lie  loaded  and  unloaded. 

Punch  press  is  equipped  with  a  die  that  holds  instrument 
panel  molding  while  a  punch  pierces  hole  formerly  cored 


Ring-shape  metal  bushing*  are  applied  to  ventilator  win 
(low  handle  escutcheons   in  a   similar  operation.     Another 
dial   fixture   is  used,  and  the  insert   is  forced  home  by  the 
press   ram  after   indexing  to  the   position   below   the   ram. 
All  the  operator  does  is  to  load  and  unload  the  part--,  mucl 
;i-   in  other  operations  described. 

Ford  instrument  panel*  are  among  the  larger  injection 
molded  part*  produced  in  this  plant.  Initially,  a  hole  was 
cored  by  a  pin  near  one  end  of  each  molding  hut.  a*  the 
plastics  (lowed  around  the  core,  it  left  a  blemish  that  looked 
like  a  crack  in  the  molding.  A*  the  hole  was  through  a  thin 
section  and  could  IK-  pierced  (punched)  easily  without  a  re- 
*tilting  blemish,  the  original  method  wa*  replaced  by  punch- 
ing. 

The  hole  is  made  in  a  simple  die   in  an  ordinary  punch 
pre**  *etup.     The  die  merely  clamp*  the  part  -ecureh 
it  is  placed  by  hand  and  pilots  the  punch  a*  it  de*cetid*  to 
pierce  the   hole.      In  thi*  ca-c,   the   pre**   i*  controlled   by  a 
pair  of  push  buttons  and.  a*  the  thumb  of  each  hand 
to  press  the  buttons,  the  hand*  must  In-  away  from  the  die 
;md  punch,  providing  the  desired  *afety  precaution*.     Again, 
the  s|>ced  of  operation  depends  u|>on  the  ability  of  the  opera- 
tor to  put  the  moldings  in  place  and  remove  them.  a- 
o|K-ration  is  nearly  instantaneous.     By  having  the  molding 
properly  supported,  any  tendency  for  it  to  crack  under  punch 
impact  is  avoided. 

As  explained  in  a  prior  article,  Ford  radio  grille*  arc 
injection  molded,  the  grille  having  bow-shaped  bars  with 
openings  between.     Before  the  grille  i*  a**embled  to  the  in- 
strument panel,  a  screen  of  fine  mesh  must  IK-  applied  to  tin- 
rear  surface  of  the  grille.     This  screen  prevent*  particle*  ot 
dirt  or  insects  from  passing  through  the  opening*  hut  <!,*•* 
not  interfere  with  sound  from  the  speaker  passing  th- 
in  addition,   it   masks  parts   of  the   set   that   could  1" 
otherwise  through  grille  o|>emngs. 

Fastening  Screen 

The  screen  must  be  well  fastened  to  prevent  vibrations 
set  up  by  sound  waves.  To  fasten  it  with  screw*  would  be 
a  slow  job,  but  it  can  be  fastened  by  applying  localized  heat 
to  soften  the  plastics  in  small  spots  on  the  rear  surface  of 
the  grille  and  by  exerting  at  these  spots  enough  pre**nre 
to  cause  some  of  the  pla*tic*  to  How  through  the  » 
freeze  and  lock  the  screen  to  the  plastics.  Thi*  i*  done,  of 
course,  without  marring  the  outer  surface  of  the  grille,  only 
the  inner  and  hidden  face  being  affected. 

Screen  is  provided  cut  to  si/e  and  with  o|<ciiing*  for  lug- 
and  bosses  that  are  molded  on  the  inner  face  of  the  grille  for 
convenience  in  fastening  the  grille  to  the  instrument  panel. 
The  initial  fastening  of  the  screen  i*  done  with  a  soldering 
iron,  which  is  pressed  again*!  the  inner  face  of  the  screen  by 
hand.  No  solder  is  used,  of  course,  but  the  plastic*  -often* 
and  flows  and  then  cools  to  prevent  the  screen  from  shifting 
in  the  following  operation. 

Final  Securing 

Final  fa-tcning  i*  done  in  a  die  placed  in  a  light  pre**.  In 
the  lower  half  of  the  die.  curved  to  grille  contour,  then-  i* 
merely  a  cu-hion  of  *oft  a-lx'-to-  -heel  against  which  the 
grille  is  laid  and  held  against  shifting. 

I  he  up]K-r  die  contain*  thirty  heated  point*  or  punche- 
*o  di*po*cd  as  to  bear  on  the  desired  fa-tcning  points  when 
the  die  i*  clo-ed.  Aside  from  the  punches,  the  up|K-r  die 
has  at«mt  the  contour  of  the  inner  lace  of  the  grille  and  the 
punche-  arc  *o  placed  that,  a*  the  die  i>  closed,  all  punches 
bear  at  the  -a me  time. 

To   heat    the    punche*.    the    up|ier    die    ha*    electric 
ridge  heating  element*  and.   when   the  die   i*   lowered,   the 
pla-tic-  i*  healed  and   Hows  only  where  the  punche- 
contact  at  ,*H  point-  and  apply  heat  and  pre— urc  to  the  grille-. 
It   require*  only  a  few    -ccond-  t"  put  each  grille  in  place. 
( (  unliniifii  OH  page  96) 


(KTOHKR 


Kubkrrmaid  products  lAou'n  rourtrnv  of  The  Wnnster  Rubber  Co.,  W water ,  OAio 


These  household  products  are  representative  of  the  colored  sample  of  compounded  stocks,  or  for  color 

•vide  variety  of  articles  that  may  be  made  in  brilliant  or  compounding  information,  please  write  Dept.     HP-1, 

delicate  colors  from  HYCAR  synthetic  rubber.  And—  B.  F.  Goodrich   Chemical  Company,  Rose  Building, 

idequate  quantities  of  HYCAR  are  now  available.  For  Cleveland  15,  Ohio. 


*»  v.  I  r.i.  Of. 
IARGEST    PRIVATELY    PRODUCED    BUTADIENE    TYPE 


B.  E  Goodrich  Chemical  Company 


A  DIVISION  OF 
THE  B.f.  GOODRICH  COMPANY 


N  PLASTICS 
ND  METAL 


PLASTICS,  metals  and  plastic- 
metal  combinations  are  opening 
new  fields  in  design  as  illustrated 
by  this  assembly  made  by  Auto-Lite. 
The  spoke  retainer,  made  of  thermo 
setting  plastic,  carries  chrome-plated 
stampings  at  each  end  and  hidden 
inserts  to  hold  the  jewel-like,  three 
dimensional,  thermo-plastic  center  horn  button. 
Another  example  of  craftsmanship  combined  with 
utility  ...  all  available  under  one  roof  at  the 
Bay  Manufacturing  Division  of  Auto-Lite. 

THE  ELECTRIC  AUTO-LITE  COMPANY 

D.ttoit  2,  Mich.  Box  Mo/»/r-ortvr«io  0-viwo"  Boy  City,  Mich. 


Tun*  In  tht  Auto-lit*  Radio  Show  Starring  Dick   Haym.l 
Ev»ry  Thuridoy  Nicjhl.  9,00  P.M.-E.T.  on  CoS 


W^T 


Fig.  1.  Free-flowing  vinyl  compound  was  required  to  lock  firmly  around  iron  insert,  core  of  accelerator  pedal 

Molded  Vinyls  Solve 
Many  Problems 

Elastomerics  possess  properties  which  make  possible 
a  variety  of  formulations,  and  wide  range  of  prices 


p/ostics  Field  Editor 


rHE  accelerated  use  of  vinyl  films  and  sheets  in  the  past 
two  years  is  perhaps  the  most  sensational  single  devel- 
ipment  in  an  industry  which  is  replete  with  sensations.    So 
liVctive  are  these  plastics  for  the  many  familiar  applica- 
tions to  which  they  have  been  put  that  there  is  no  question 
put  that  they  will  be  permanent.     This  happy  development 
las  had  one  negative  aspect,  in  that  it  has  tended  to  put  the 
'nolded  vinyl  plastics  in  the  background.    At  least,  there  are 
many  end-users  of  plastics  who  have  heard  very  little  about 
jhem. 

1  Yet  intensive  'research  has  been  going  on  in  this  field,  and 
pne  of  the  major  producers  has  been  steadily  allocating  a 
Substantial  portion  of  its  resins  to  molding  compounds, 
^pi  cially  of  the  elastomeric  variety.  While  the  rigid 
vinyls  also  have  their  distinctive  uses,  as  for  phonograph 
records,  they  do  not,  in  some  applications,  have  a  clean-cut 
idvantage  over  competitive  materials,  including  other  types 
Df  plastics.  But  the  elastomerics  have  the  virtues  of  the 


rigid  variety — good  tensile  strength,  dimensional  stability, 
resistance  to  water  and  chemicals,  dielectric  strength — and, 
in  addition,  a  unique  resistance  to  abrasion  and  flexibility. 
They  can  indeed  be  molded  to  any  degree  of  elasticity,  and 
toughness  depending  on  the  formulation,  with  a  durometer 
ranging  from  55  to  100;  and  they  can  be  finished  with  a 
high  gloss  like  the  rigid  vinyls.  Both  types  have  an  un- 
limited color  range,  though  the  elastomerics  cannot  be  had 
in  as  clear  transparents  as  the  rigid. 

Whereas  the  rigid  vinyls  are  unfilled  and  unplasticized, 
the  elastomers  can  be  filled  with  clay,  calcium  carbonate, 
aluminum  hydrates,  lead  and  other  metallic  powders,  and 
treated  with  many  kinds  of  plasticizers.  These  additives 
make  possible  the  varied  formulations  referred  to  above,  as 
well  as  a  wide  range  in  price,  for  the  enumerated  fillers 
cost  from  1  to  65c  per  Ib,  and  the  usable  plasticizers  from 
6  to  60c. 

This  article  will  deal  with  several  elastomeric  vinyl  items 


.KTOBER  1946 


PLASTICS 


37 


Fig.  2.  Hand  hold  (upper  right)  is  used  to  remove  brake 
pedal  covers,  with  undercuts,  from  press  after  molding 


Fig.  3.  Undercuts,  flexible  and  rigid  sections,  were  prob- 
m  molding  Eureka  vacuum  cleaner  brush  holder 


which  have  been  produced  by  the  Hungerford  Plastics  Cor- 
poration which  will  give  the  reader  an  idea  of  the  problems 
these  plastics  can  solve. 

Fig.  1  shows  a  two-cavity  shot  of  an  accelerator  pedal  in 
which  vinyl  plastics  have  replaced  rubber.  As  in  the  con- 
ventional pedal,  the  core  is  of  metal.  Since  the  vinyls  won't 
conveniently  bond  with  this  insert,  the  problem  was  how  to 
lock  it  securely  in  place.  The  second  problem  was  to  obtain 
a  formulation  having  the  maximum  wear  and  oil  resistance. 

A  solution  to  the  first  problem  was  found  in  a  formulation 
which  quickly  flows  around  the  insert  in  the  die.  By  means 
of  holes  punched  in  the  insert,  the  vinyl  is  pinned  from 
the  back  to  the  under  surface,  and  at  no  fewer  than  14  points 
the  material  forms  overlaps  against  the  insert,  thus  making 
.1  -trotig  locking  device.  Two  of  the  points  serve  also  as 
locating  points,  and  one  of  these  two  is  in  a  knob-like  pro- 
jection of  the  plastics  (at  lower  right  in  Fig.  1),  where  the 
accelerator  pedal  arm  is  subsequently  pressed  in,  the  hole 
being  undcrsi/e  t<>  make  a  tight  fit. 

As  thr  illustration  shows,  each  piece  is  double-gated,  bc- 

th«-    plastics    h.i-    to    Mow    through    small   aperture--. 

According  to  Jack  Sandier,  chief  chemist  of  HiuiKcu'nnl.  it 

is  desirable  for  most  vinyls  to  be  molded  with  double  gates 

because  it  is  important  to  get  the  material  into  the  mold  as 


rapidly  as  possible,  and  also  because  this  permits  the  prodt 
tion  of  heavy  sections  with  undercuts. 

A  point  of  interest  in  the  die  design  is  that  the  metal  ins< 
is  held  in  place  by  hinge  ears.  Because  of  the  length  <>f  t 
insert  plate,  locating  points  are  needed  to  position  it  ac- 
curately and  to  prevent  it  from  wobbling  during  the  molding 
cycle. 

It  was  important  to  calculate  the  pressure  to  exert  on  the 
material  in  order  to  keep  it  from  filling  the  under  side  of 
the  plate  and  to  flow  it  where  it  was  wanted — on  the  upper  I 
side.    Also,  the  plastics  had  to  be  kept  off  the  hinge  ears  and 
yet  made  to  flow  over  the  reinforcing  flange.     After  due 
experimentation,  a  pressure  of  14,000-16,000  psi  was  ar- 
rived at.    The  parts  are  molded  in  an  8-oz  Reed-PrentlH 
machine,  the  back  temperature  of  the  cylinder  being  35"    F 
and  the  front  temperature,  300°.    Of  the  4.7  oz  of  molding 
compound  used,  42  oz  go  into  the  pieces  produced  in  the) 
two-cavity  mold.    Something  will  be  said  later  on  about  the  j 
re-use  of  the  material  forming  the  gates,  runners  and  sprues. 

Undercuts  No  Hindrance  to  Molding 

In  the  molding  of  the  brake  pedal  covers  (Fig.  2),  which 
are  later  pressed  on  to  the  pedal  body,  the  problems  were. 
first,  to  flow  around  a  fairly  deep  undercut,  and,  second,  to 
provide  for  a  means  of  stripping  them  off  the  mold  at  the 
end  of  the  cycle.  The  same  freely  flowing  formulation  as 
was  used  for  the  accelerator  pedal  was  the  answer  to  the 
first  problem.  Extra-heavy  runners  and  gates  were  tlv 
tion  to  the  second,  together  with  a  hand-hold  molded  in 
(shown  in  upper  right  hand  of  the  illustration)  by 
of  which  the  snot  could  be  yanked  out  of  the  mold.  Thanks 
to  the  elasticity  of  the  material,  the  undercuts  do  not  anchor 
the  shot  so  strongly  as  to  resist  this  pull,  and  the  thickness 
of  the  section  prevents  distortion. 

Although  both  the  accelerator  pedal  and  the  brake  cover 
pedal  are  produced  in  a  black  compound,  there  is  a  pos- 
sibility of  styling  these  utilitarian  parts  in  brighter  colors  to 
harmonize  with  the  general  color  scheme  of  the  car.  If  that 
seems  a  little  far-fetched,  a  bright  color — red,  for  example — 
could  still  be  used  even  for  the  strictly  utilitarian  purpose 
of  being  more  strikingly  visible. 

The  brush  holder  used  in  the  well-known  Eureka  vacuum 
cleaner  is  made  of  an  elastomeric  vinyl  compound.  This  is 
illustrated  in  Fig.  3.  In  the  sectional  view  shown  at  the 
right,  the  varying  thickness  of  the  piece  can  be  seen,  n 
as  the  two  undercuts,  one  of  the  outside  just  below  the 
collar,  where  the  brush  is  locked  in  the  assembled  cleaner, 
and  one  inside  under  the  collar,  necessitated  by  the  shape  of 
the  piece  and  its  function.  The  thin  section  measures  .068*, 
while  the  heavier  sections  grade  up  to  .475".  The  task, 
then,  was  to  mold  a  piece  the  body  of  which  was  thick  and 
fairly  rigid,  and  the  neck  fairly  flexible  so  that  the  brush 
could  be  forced  on  over  it. 

To  meet  all  these  conditions,  a  more  rigid  type  of  elas- 
tomer was  formulated,  and  to  prevent  the  thin  neck  from 
being  too  stiff  the  compound  was  loaded  with  calcium  car- 
bonate filler,  which  also  brought  down  the  cost. 

hi  another  product,  Hungerford  also  was  faced  with  the 
problem  of  molding  a  combination  thin  section  (.021' 
thick  section  (.125").    This  was  a  tee  for  the  sun  still  made 
by  the  Watertight  Fastener  Co.,  which  also  had  to 
maximum  clarity  and  meet  a  load  test  of  75  Ib.    'I  h. 
.195"  high  and  .708"  at  its  widest  point,  and  another  pi 
was  to  get  a  hole  in  its  narrow  neck 

This  was  solved  by  a  die  so  constructed  that  there  was  no 
tl.ish  around  the  thin  section. 

The  tees  are  molded  in  30-cavity  dies,  on  a  molding  cycle 
of   1')  sec.     It  is  interesting  to  note  that  the  cotupai 
produced  this  small   unit  on  an  8-oz  machine,  each 
requiring  so  little  material  ( 1,200  are  obtained  from  a  pound 
i  (  .'iitiHiifd  on  page  76) 


38 


I'hASTICS 


OCTOBER  1346 


CHEAT 


•SSES 


PLASTICS 
INJtCTUIN 
MOLDING 


PLASTICS  INJECTION  PRESSES 

offer  these  advantages  •  Economical  Produc- 
tion •  Versatile  Performance  •  Simplified 
Operation  •  Lower  Mold  Costs  •  Low  Orig- 
inal Investment. 

Custom  molders,  manufacturers,  laboratories 
and  schools  are  finding  these  1  oz.  molders 
extremely  practical — well  suited  for  a  wide 
range  of  production  and  research  requirements. 


FOR  THESE 
FREE    BULLETINS 

which  illustrate  and  de- 
scribe the  Van  Dorn 
Plastics  Injection  Presses 
and  their  applications. 


CLEVELAND    4,    OHIO 


2683     EAST    79TH    STREET 


OCTOBER  1946 


PLASTICS 


39 


Compression  Mold  Design 


/  /y°'"1   \J"  '^ono  Part  II.   Cavity  structure,   parting  line 

position  and  ejection  method  influence  mold  performance 


COMPRESSION  molds  may  be  made  in  one  of  several 
ways.  The  various  cavities  may  be  machined  (1) 
into  one  block  of  steel;  (2)  in  individual  blocks,  and  set 
into  the  holes  in  the  chase;  or  (3)  in  individual  blocks  and 
then  doweled  and  screwed  to  a  base  plate  or  die  -hex-.  The 
method  selected  will  depend  on  the  si/e  and  shape  of  the 
piece,  the  number  of  cavities  in  the  mold,  and  the  amount 
of  production  scheduled  for  the  mold. 

On  small  molds  it  is  usually  chca]icst  to  machine  tin- 
several  cavities  out  of  i>m-  Mock  of  steel  <  Fig.  1  i.  The 
punches  are  then  bolted  and  doweled  to  the  tup  plate,  and 
the  two  halves  are  lined  up  with  guide  pins.  The  two 
disadvantages  of  this  system  are  the  danger  of  warping 
•  if  the  cavity  plate  in  hardening  and  the  expense  of  re|«iir 
ing  a  damaged  cavity. 

To  overcome  these  undesirable  features,  a  multicavity 
mold  is  often  made  with  tli<-  -evctal  cavities  machined  into 
blocks  which  arc  then  set  into  holes  Ixircd  or  milled  into  the 
or  cavity-retaining  plate  (  l-'ig.  _'i.  The  individual 
cavities  are  hardened,  but  the  cha-c  remains  soft  and  the 
guide  pins  slide  in  hardened  Im-lnni;,  which  are  pi 


into    the   chase.      This   construction   eliminates   danger   ofj 
war  page   in  the  plate   in  heat   treating  and  makes  possible 
the   replacement  of  damaged  cavities.     If  hobbed  cavities 
are  to  be  used,  this  type  of  construction  is  the  only 
tical   answer  to  the  problem. 

Sometimes  on  short  run  jobs  mold  cost  is  lowered  !>y» 
omitting  the  cavity-retainer  plate  and  bolting  and  doweling 
the  cavities  to  a  base  plate  or  die  shoe  (Fig.  3).  This 
construction  should  be  used  with  caution  as  there  is  con- 
siderable danger  of  producing  poorly  aligned  moldings 
caused  by  spring  in  the  long  unsupported  guide  pins.  Also 
heating  is  not  as  uniform  as  with  the  other  method-  »f 
construction,  and  longer  cures  will  be  the  penalty  for  the 
saving  in  mold  cost 

When  laying  out  the  cavity  and  punch  for  a  compn 
mold,  the  designer  must  be  constantly  alert  for  pitfalls  which 
if  overlooked  may  cause  c\re-si\e  dicmaking  cost-  oi 
iliiction    troubles       lie    should    visuali/e    the    methods    the 
toolmakcr   will   use  to  make   the   various  parts,  and   ti\    to 
make   his  design    -n  a-  to  av.nil   time  consuming   methods 
and   operations   whenever   |*>ssjble.      l-'or  example,  tl 


40 


I*  LAST  it'S 


OCTOBER  I'M* 


*Over  a  quarter  of  a  Century 


Hong 


Michiga 

Learned 
the 


aided 


f 

'*  PLASTICS 


Many  years  ago  we  graduated  from  the  primary  classes  of  the  school  of 
plastics.    Today,  Michigan  Molded,   for  all  its  small   size  —  indeed, 
BECAUSE  of  this   modest  size  —  furnishes   a  consistent,   magnificent 
standard  of  quality,  plus  versatility,  in  extrusion,  injection  and  compres- 
sion!   Yes,  MICHIGAN  MOLDED  is  an  old-timer  with  visionary  eyes  — 
versed  deeply  in  the  craft  of  plastics,  knowing,  as  well,  how  important  it 
is  to  STAY  SMALL  in  order  to  furnish  each  customer  with  the  highest 
degree  of  attention!    Today,  with  a  vast  backlog  of  orders,  Michigan 
Molded  is  not  too  busy  to  give  sincere  and  earnest  consideration  to  your 
plastic  requirements.     We   prosper   by   developing  and   producing   new 
applications,  and  always  enjoy  solving   new   customer   problems.     You 
are  assured  of  personalized  consideration  at  Michigan  Molded. 


ICHIGAN 

OLDED   PLASTICS,  INC 


OCTOBER  1946 


PLASTICS 


41 


—  PUfKHPiATt 


—  CAVITY  PLA 


BACKING  PLATS 


mot*  OUT  PM 


SfCTIOM   A-A 


Fig.    1.     A   four-cavity   compression  mold — of   the   flash 
type — with   cavities   machined   into   one   block   of   steel 


TOO  STCAM 
PLATf 


STIAM 
CHANHtL. 


omw-^l 

~ 


3D 


a 


Fig.  2.    Cavities  may  be  machined  into  separate  blocks, 
which  are  then  set  into  chase  (sectional  view  sketched) 


Fig.  3.    As  third  method,  the  cavities  and  punches  may 
be  set  on  a  die  shoe  and  bolted  and  doweled  to  plates 


of  small  endmills  in  deep  narrow  grooves  is  difficult,  and 
the  filing  and  polishing  required  after  the  machining  is 
extremely  tedious.  Often  a  pieced-up  or  laminated  cavity 
construction  will  result  in  a  cheaper,  better  running  mold. 
It  is  usually  cheaper  to  set  in  the  bottom  of  a  cavity  which 
has  considerable  detail  than  to  attempt  to  machine  it  in  the 
solid  block  way  down  in  the  cavity  where  milling  i:-  diffi- 
cult, measuring  uncertain,  and  polishing  impossible. 
Sketches  in  Fig.  4  are  examples  of  pieced-up  cavities. 

Compression  molding  develops  high  pressures  in  the 
molding  material  as  it  flows  around  the  cavity,  and  the 
designer  must  be  on  the  lookout  for  weak  sections  in  the 
mold  cavity  or  punch  (Fig.  5,  left).  Such  edges  arc 
likely  to  appear  on  the  punch.  Fig.  5,  center,  shows  a 
condition  which  frequently  occurs  in  the  design  of  molds 
for  electrical  outlet  plugs,  etc.  Here  the  punch  must  ex- 
tend out  beyond  the  piece,  and  a  corresponding  core  print 
must  be  placed  in  the  cavity  to  receive  it.  Radii  on  the 
top  half  of  a  piece  will  also  cause  bad  corners  on  the 
punch  (Fig.  5,  right),  and  redesign  must  be  resorted  to 
unless  the  type  of  mold  can  be  changed. 

Before  the  final  design  is  made  for  any  mold,  the  piece 
design  should  be  carefully  studied  with  a  thought  to  redesign 
it  to  make  it  more  moldable  and  to  keep  the  mold  cost  down. 
The  piece  designer  should  be  consulted,  and  his  perm 
requested  to  incorporate  desired  changes.  This  redesign- 
ing may  often  save  the  customer  much  time  and  money, 
and  it  should  never  be  overlooked. 

When  beginning  the  mold  layout,  the  position  of  the 
parting  line  will  have  to  be  determined.  Although  it  is 
usually  located  so  that  the  mold  works  as  simply  as  possi- 
ble, occasionally  simplicity  of  operation  of  the  mold  and 
lower  mold  cost  will  be  sacrificed  for  a  location  which 
facilitates  cleaning  of  the  flash.  Also  close  tolerano 
difficult  to  hold  across  the  parting  line,  and  this  will  some- 
times determine  its  location. 

On  most  part  designs  the  logical  position  of  the  parting 


Fig.  4.    Since  grooves  In  bottom  of  cavity  are  difficult  to  machine,  measure  accurately,  and  polish,  either  the  con- 
struction in  center  or  at  right  should  be  used,  depending  on  design  of  piece.    Pieced  up  cavities  are  often  cheaper 


42 


OCTOBER  1916 


DOTTfO  LINC  SHOWS  IMCOBBCCT  DISItM 
tVfAK  EDGC  ON  0UHCN 
\ 


COBOECT     ' 
COfSTBl/CT/Ot, 


Fig.  5.  Construction  at  left  gives  a  weak  section  in  punch.  Here,  the  solution,  depending  on  design  of  the  piece  and 
the  material  used,  is  (1)  to  redesign  the  mold  so  that  horizontal  flash  (broken  lines)  strengthens  the  punch  or  (2)  to 
invert  mold  so  that  grooves  come  in  the  cavity  as  in  Fig.  4.  In  center  sketch,  punch  extends  into  core  print  in  cavity 
to  form  outside  chamfer,  thus  avoiding  a  weak  corner.  Bad  construction  at  extreme  right  weakens  corner  of  the  punch 


line  is  obvious,  but  sometimes  the  various  factors  must 
be  carefully  weighed  before  the  mold  design  is  started.  If 
inserts  are  to  be  molded  into  the  piece,  it  is  well  to  design 
the  mold  so  that  the  inserts  are  in  the  bottom  half  whenever 
possible.  Inserts  in  the  top  half  of  the  mold  may  fall  from 
their  pins  as  the  mold  closes,  thus  causing  rejects  or 
possibly  damage  to  the  mold. 

Election  Methods 

The  problem  of  ejecting  the  casting  from  the  mold  is 
an  important  one,  and  often  means  the  difference  between 
a  good  molding  job  and  a  continual  headache  for  the 
production  department. 

Knockout  pins  are  the  usual  method  of  ejection  on  com- 
pression molds  (Fig.  6).  They  may  be  either  in  the  top 
or  bottom  half  of  the  die,  as  most  presses  are  designed  to 
use  either  a  top  or  bottom  ejector  mechanism.  Molds 
with  top  knockouts  are  to  be  preferred,  as  the  surface 
formed  by  the  punch  is  usually  the  non-appearance  surface 
of  the  piece,  and  marks  left  by  the  knockout  pins  on  this 
side  are  therefore  not  objectionable.  Also,  when  the  pieces 
are  knocked  off  the  punch,  they  fall  free  of  the  top  half 
and  can  be  caught  by  a  piece  of  board  as  they  drop  (Fig.  7), 
thus  speeding  up  the  operation  of  the  mold. 

However,  piece  design  is  often  such  that  the  pieces  will 
tend  to  stick  in  the  cavity  half  as  the  mold  opens.  In  this 
case  the  designer  will  have  to  specify  bottom  knockouts. 
This  is  especially  true  of  deep-draw  jobs  where  suction 
holds  the  piece  in  the  cavity.  When  this  is  the  case,  the 
pins  will  have  to  be  in  the  bottom,  and  the  marks  left  by 
them  will  have  to  be  cleaned  off  after  molding  if  they  are 
considered  objectionable. 

Often  the  end  of  the  knockout  pin  can  be  decorated  in 
such  a  way  that  its  mark  on  the  molding  is  not  objection- 
able. In  many  cases  the  designer  can  make  the  castings 
stick  on  the  punch  by  calling  for  undercuts  or  reverse 
draft  on  the  punch  (Fig.  8).  These  pickups  must  not 
be  too  deep  or  the  piece  may  crack  when  the  ejector  pins 
knock  it  off  the  punch.  Their  depth  is  usually  established 
by  trial  and  error  as  they  can  easily  be  deepened  by  a  hand 
grinder  if  they  prove  inadequate. 

Elector  Pins  for  Mold  Halves 

The  design  of  some  pieces  is  such  that  the  mold  designer 
cannot  be  sure  which  half  of  the  mold  the  castings  will 
remain  in  as  it  opens.  In  this  case  he  should  design  the 
mold  with  ejector  pins  in  both  top  and  bottom  halves.  This 
will  add  to  the  cost  of  the  die,  but  may  avoid  much  loss 
of  production. 

The  knockout  pins  should  be  carefully  located,  and  should 

be  ample   in   size  and  number  to  eject  the  piece  without 

warping  it  or  breaking  through  thin  wall  sections.     Small 

diameter  pins  tend  to  push  through,  causing  rejects,  and 

(Continued  on  page  73) 


~LT 


CiAMP  SLOT  GWD£  PIN  BUSHIHG 


Fig.  6.    Compression  mold  with  both  top  and  bottom  knockout 
pins.    Proper  ejection  is  an  important  phase  of  mold  design 


OCTOBER  1946 


PLASTiCS 


43 


No  matter  in  what  direction  compact  is  turned,  one  or  more  ol 
it*  flame-polished  facets  always  appears  to  be  ablaxe  with  light 


Fabricating  Acrylic  Compacts 

Machining  plays  an  important  role  in  turning  out  attractive 
methyl  methacrylate  face  powder  compacts  of  high  quality 


u 

0 


ert  C.    L,l 


o6e 


Al.'l  I  lOl't  ill  injection  molding  has  made  enormous 
strides,  there  are  nevertheless  a  number  of  products 
in  which  fabrication  still  plays  an  important  role.  Usually 
the  articles  produced  by  the  two  different  processes  are  not 
competitive,  the  machined  item  naturally  falling  into  a 
higher  price  category.  A  case  in  point  is  the  face  powder 
compact,  which  has  been  injection  molded  in  a  wide  variety 
of  good  designs,  but  is  also,  in  a  more  limited  quantity, 
produced  by  fabrication.  One  such  quality  job  has  been 


The  three  milling  cutters  are  cam-operated  as  compact 
hall,  vitible  on  light  spindle,  is  rotated  between  them 


achieved  by  Frank  P.  Bucklein,  Los  Angeles,  utilizing  an 
optical  grade  of  cast  acrylic  which  is  prepared  by  casting 
Ix-'twecn  Pyrex  plates  and  requires  three  weeks  to  set. 

This  material  is  free  of  internal  stresses,  contains  no  ph- 
ticizer,  and  will  neither  warp  nor  deform  under  ordinary 
service  conditions.  It  has  excellent  "plastics  memory." 
which  is  a  desirable  quality  when  precision  construction  15 
required,  rendering  impermanent  any  slight  deformation 
caused  by  machining,  polishing,  joining  or  dyeing. 

Mr.    Rucklfin  has   found   highspeed    steel   cutting 
very  practical  for  tlii>  work,     ("hip  clearance  is  expedited 
and  clean  .-hop  condition-   in-tired  by  utilizing  blower-  to 
carry  pla-tic-  chips  away  from  the  cutting  machine  tool  beds. 

After  -awing  the  -heel  pla-tic-  to  shajie.  the  lir-t  opera- 
tion  in  producing  the  compact  is  face-lxiring  of  the  l>ottoin 
half  to  form  the  powder  container,  and  of  the  tip|xM  half  M 
receive  the  mirror  or  metal  plaque  in-ert.  1  hi-  i-  done  on 
a  special  machine  de-igned  by  Itucklein.  It  is  only  • 
-ary  to  seat  the  compact  half  on  a  lace-plate  and  pull  a 
lever.  Automatic  stops  prevent  boring  too  deeply.  The 
machine  i-  powered  by  two.  1  hp  motors — one  for  the  upper 
and  one  for  the  lower  -pindlc-. 

Facet  Cuffing 

The  -rcond  o|MT.itioii  i-  cutting  facet-,  the  |xttlern  of 
which  i-  identical  to  that  n-ed  in  diamond  cutting.  I  Imv 
with  an  eight-sided  compact,  twenty-four  facet-,  eight  in 
each  of  three  plane-,  are  nece— ary.  In  the  automata 
chine  which  Hucklein  designed  for  this  o|»-ration.  there  are 
three  facet  cutter-  mounted  in  the  plane  of  the  required  cut- 
ting angle.  Ihc-c  an-  cam-operated,  moving  in  and  out  .1- 
the  coni|>act  half  rotate-  under  the  cutting  blade-.  <  iilti-r 
(Continued  on  page  71 ) 


44 


OCTOKKK   1"U> 


THE 


CHAMP 


Heats  6  Pounds  (96  ozs.)  in  ONE  MINUTE 


Whenever  you  see  the  THERMAL!  Diamond  on  an 
HF  Healing  Unit,  you  can  bet  your  last  dollar  on 
the  vfmocf  in  performance. 

We'll  gladly  give  you  technical  and  engineering 
data  about  every  size  THERMALL  Unit  Users  say 
that  we  are  conservative  in  our  power  ratings. 
They  tell  us  that  THERMALL  HF  Heating  Units 
consistently  deliver  more  than  rated  power;  preheat 
faster  than  we  claim. 

Time  after  time,  users  have  said  they  were  "amazed 
at  THERMALL  performance." 

If  you  have  a  pre-heating  or  molding  problem  of 
any  kind  and  want  technical  advice  or  assistance 
— write  us.  We  will  assist  you  by  assigning  one 
of  our  technical  representatives  to  your  problem 
without  obligation. 

When  you  want  a  job  done  day  in — day  out,  re- 
member that 

THERMALL  means  PERFORMANCE 


WRMILl  THERNALL  THERMAU 

Hornet  Bantam  Champ 


The  THERMALL  Chomp  occupies  only 
20x30  inches  of  your  floor  space.  Heals 
96  ounces  compound  to  molding  temper- 
ature in  1  minute.  Completely  portable. 

Bulletin  S  gives   specifications   and   details   of 
all  THERMALL  HF  Units.    It's  free,  on  request. 

W.      T.      LA      ROSE      &      ASSOCIATES 

635  Second  Avenue  Troy,  New  York 

Representative,  in  All  Principal  Cities 
Export:  Omni  Products  Corp..  40  East  34th  St..   New  York   16.   N.  Y. 


OCTOBER  1946 


PLASTICS 


45 


Motion  in 


e  mi 


Table-sized  Christmas  tree  adorned  with  colorful  "Noma 
Bubble-Lites"    forms    a    strikingly    effective    centerpiece 


hi>u-r>  ;i  Miiall  bulb.  These  components  are  permanently 
assembled  in  a  single  unit. 

The  glass  "candle,"  made,  filled  and  sealed  at  the  com- 
pany's Bubble-Lite  plant  in  Peru,  Ind.,  is  a  vial  containing 
a  low-boiling-point  liquid  which  bubbles  under  the  heat 
generated  by  the  bulb  just  beneath  it,  the  bubbles  rising 
to  a  partial  vacuum  above  the  liquid  level.  The  light  from 
the  bulb  is  transmitted  up  through  liquid,  bubble  and  glass 
to  the  flame-shaped  tip  of  the  vial,  supplying  a  candle-flame 
effect  at  the  top.  At  present,  the  liquid  used  is  clear  trans- 
parent, but  research  is  being  conducted  toward  achieving 
liquids  of  transparent  color  that  will  not  fade  under  light 
and  heat,  with  the  purpose  of  producing  a  striking  and  un- 
usual effect  when  the  vari-colored  "candles"  are  placed  upon 
the  tree. 

The  light  bulb  dissipates  about  4.5  w,  which  is  sufficient 
to  provide  a  light  brilliant  enough  for  transmission  through 
the  two-toned  plastics  base,  as  well  as  upward  through  the 
vial,  and  to  offer  an  amount  of  heat  which  will  be  adequate 
to  cause  the  liquid  to  boil,  thus  providing  the  bubbles  that 
supply  the  unique  and  distinctive  "animation"  feature  to 
these  unusual  lights. 

Plastics  was  found  to  be  a  perfect  medium  for  the  base, 
which  is  an  assembly  of  two  cemented  shells  of  different 
color.  Stanley  K.  Bindman,  manager  of  the  firm's  injection 
molding  plant,  pointed  out  that  a  number  of  definite  re- 
quirements controlled  the  choice  of  the  plastics  material  for 
the  base  in  which  the  bulb  is  housed  and  from  which  the 
bubble  vial  extends.  For  one  thing,  the  material  had  to 
endure,  without  distortion,  the  heat  developed  within  the 
base  by  the  bulb. — an  ambient  temperature  reaching  about 
140°  F,  with  a  relatively  slow  rate  of  dissipation.  Also,  in 


AN  EFFECT  of  animation  to  enhance  the  color  and 
beauty  of  modern  lighting  for  Christmas  trees  will  be 
provided  this  year  in  an  innovation  to  be  marketed  by  the 
Noma  Electric  Corp.,  of  New  York.  Called  Bubble-Lite, 
it  is  said  to  be  the  first  successful  achievement  of  motion 
in  Christmas  tree  lighting  that  is  integral  with  the  light 
it-i-lf.  Several  years  of  experimentation  by  the  company 
preceded  the  development,  which  has  been  a  project  of 
I  li-nri  Sadacca,  who  is  president  of  Noma  and  its  many  sub- 
-icliaries. 

The  Bubble-Lite  is  to  be  marketed  as  an  individual  light, 
fur  use  in  any  series-type  15  v  Christmas  tree  light-socket, 
and  in  a  complete  string,  or  set,  of  nine  Bubble-Lite  units. 
J'i-i-ph  II.  Ward,  executive  vice  president  of  Noma,  states 
that  although  the  production  of  these  lights  for  the  current 
year  is  limited,  it  is  expected  that  full  production  will  be 
achieved  next  year. 

The  effect  of  a  Christmas  tree  trimmed  with  the  new 
lights  is  one  of  shinirrK-ring,  lively  color.  And  plastics  has 
been  an  outstanding  factor  in  making  this  development 
feasible.  Bubble-Lite  consists  of  a  candle-shaped  glass  tube 
in  which  bright  bubbles  are  continually  wavering  upward, 
the  tube  being  mounted  in  a  two-toned  plastics  base  tli.it 


46 


Lower  hall  ol  cellulose  acetate  shell  holds  elec- 
tric bulb:  glass  vial  is  pressed  into  upper  hall 


OCTOBER  19-16 


Christinas  Tree  Lighting 

Enhancement  of  the  color  and  beauty  of  traditional  decoration 
for  Yuletide  trees  is  offered  in  a  new  lighting:  achievement 


order  to  provide  the  maximum  of  translucency,  the  shell 
had  to  be  thin — about  .030"  at  its  thinnest  section — which, 
in  turn,  brought  up  the  problem  of  impact  and  flexural 
strength.  The  colors  transmitted  through  the  shell  had  to 
be  warm,  bright  and  clear.  Ease  of  molding  and  facility 
of  assembly  were  especially  important  factors  in  large-scale 
production  such  as  was  required.  Experimentation  over  a 
considerable  period  of  time  demonstrated  that  this  variety 
of  requirements  was  best  met,  at  the  time,  by  cellulose  ace- 
tate. As  a  thermoplastic,  this  material  had  the  additional 
advantage  of  lending  itself  to  a  shrink-fit  operation  con- 
templated in  connection  with  assembly. 

Basic  Color  Group 

The  two-tone  shell  pairs  of  the  Bubble-Lite  base  are 
selected  from  the  following  color  group :  Red,  blue,  yellow, 
green  and  orange.  Other  secondary  shades  are  to  be  added 
to  the  line,  according  to  present  p'ans.  At  the  company's 
injection  molding  plant,  where  mo^t  of  the  production  for 
the  base  is  handled,  the  shells  are  injection  molded  in  16- 
cavity  and  22-cavity  molds.  In  view  of  the  high  rate  of 
output  required,  additional  production  is  supplied  by  the 
Bridgeport  Molded  Products  Co.,  Bridgeport,  Conn.,  and 
the  Gemloid  Corp.,  Elmhurst,  N.  Y.  The  shells  are  fluted 
along  their  outer  surface,  in  a  design  intended  to  break  up 
the  transmitted  light  into  variations  of  light  and  shade;  it 
also  provides  additional  surface  area  for  dissipating  the  heat 
developed  within  the  material. 

No  machining  is  involved  at  any  point  in  the  production 
or  assembly  of  the  Bubble-Lite  base,  even  at  the  gate  break- 
off  point.  This  is  largely  due  to  the  design  of  the  mold. 
Flash  at  the  parting  line  is  obviated  by  very  narrow  lands 
at  the  cavities  and  by  high  clamping  pressure.  A  small, 


thin  gate  entering  the  molded  piece  at  the  end  of  a  flute- 
channel  results  in  no  appreciable  gate  mark  being  left  on  the 
piece  when  it  is  broken  away  from  the  runner.  Also  molded 
into  each  shell  are  six  vent  openings,  1/16"  in  diam,  and  six 
slots  in  the  neck  of  the  upper  shell.  The  shells  measure 
about  1  YI."  in  diam  by  y%"  in  height. 

There  are  three  main  steps  in  assembly  of  the  Bubble-Lite 
components:  Vial  base  to  upper  shell,  bulb  to  lower  shell, 
and  shell  to  shell.  For  mounting  of  the  vial  in  the  upper 
base-half,  the  neck  of  the  shell  is  expanded  by  immersion  in 
hot  water,  the  vial  is  inserted  in  the  hole,  and  the  neck  is 
permitted  to  cool  to  a  shrink-fit  around  the  vial  base.  The 
bulb  is  inserted  into  the  neck  of  the  lower  shell  and  is 
bonded  to  it  by  a  specially  developed  cement.  The  two 
assembled  units  are  then  joined  by  an  acetone  bond  of  the 
upper  to  lower  shells,  which  are  self-aligning  by  means  of 
three  round  locating  pins  molded  into  the  upper  shell.  Jigs 
are  now  being  designed  in  order  to  make  possible  more  rapid 
assembly. 

Other  Plastics  Parts 

In  addition  to  use  in  the  body  of  the  product,  plastics  are 
also  utilized  in  two  elements  of  the  complete  string  of  nine 
lights.  The  socket,  or  husk,  for  each  light,  and  the  plug  (a 
three-way  device  for  parallel  connection  of  two  additional 
strings)  are  compression-molded  of  phenol  formaldehyde  at 
Noma's  compression  molding  plant  in  Holyoke,  Mass.  These 
two  items  have  long  been  standard  in  the  company's  line  of 
Christmas  tree  lighting  products.  The  firm  is  also  looking 
forward  to  the  possibility  of  being  able  to  utilize  polyvinyl- 
chloride-covered  wire  in  production  of  these  lighting  units, 
as  soon  as  its  Ansonia  Electric  Co.  division  is  enabled  to 
increase  production  facilities.  END 


Entering  molded  piece  at  rim  of  a  flute-channel,  small 
thin  gate  leaves  practically  no  mold  mark  when  removed 


OCTOBER  1946 


PLASTICS 


A  nine-unit  string  of  "Bubble-Lites,"  in  which  light  and 
heat  combine  to  produce  effect  of  shimmering  loveliness 

47 


HAVE  YOU  A  PRODUCT  THAT  NEEDS 


COLORFUL    plastic  CONTAINERS 


ARE 


write  for  details  to 
CONTAINER  DIVISION  of- 


USE  CLEAMIITE  —  th.  "S«l.ty 

BM«  "  PU.tic  (or  .  r.«l 
"pick-up"  In    Packaging   .   .  . 


j 
/ 


from  the  beginning 


WE   START   FROM   YOUR   IDEA,   DESIGN, 
BLUEPRINT,   YOUR   MOLD   OR   OUR   OWN  — 


and  be 
all  the  way  through! 

THE  RIGHT  DESIGN 

• 

THE  RIGHT  MATERIALS 


THE  RIGHT  DIES 


THE  RIGHT  METHODS 


EXTRUSION 

and 

INJECTION 
MOLDINGS 

[  write  for  details  to  MOLDING   DIVISION  of-| 


CiLLiiPLASTic  CORPORATION 


ORP. 


PLASTIC    CONTAINERS 


PLASTIC    PRODUCTS 

46     AVENUE    I  NEWARK    5.  N.  J. 

»iw   ro»r  omci-»jo  HUM  AVIMUI  wisr  coAir.   CONTAINIR    SIRVICI   COMPANY,  ics   ANCIIIS   if.  CAI 


48 


OCTOHKK    1'Mti 


i 


fl 


1     S 

"'_«  3  S  ft  3  .M  -8 
"3   *   «  '      t.   _ 


Sleek  looking  and  modern,  new  car  body  is  molded  in  two  pieces,  one 
consisting  of  hood  and  front  fenders,  other  of  rear  deck  and  fenders 


Auto  Body  Designed 
for  Plastics 

Quickly  and  economically  formed  and  easily  repaired,  laminated 
car  bodies  may  have  many  advantages  over  steel   counterparts 


THE  long-time  dream  of  the  automotive  industry,  a  five- 
passenger  car  with  plastics  body,  has  been  prototyped 
in  Hollywood  by  laminating  Owens  Corning  ECC-1 1-162 
FibergUu  with  Selectron  5003,  a  styrene  polyester  furnished 
by  Columbia  Chemicals  Division  of  Pittsburgh  Plate  Glass 
Company. 

Made  in  two  pieces,  one  consisting  of  hood  and  front  fen- 
ders, the  other  including  rear  deck  and  fenders,  the  parts 
weigh  104  Ib  in  plastics  as  compared  with  approximately  520 
Ib  if  fabricated  of  steel. 

Aside  from  cost,  one  of  the  questions  always  raised  about 
a  plastics  body  is :  What  about  repairs  ?  To  this,  Howard 
Darrin,  the  designer,  who  has  styled  custom  autos  in 
Europe  and  this  country  for  20  years,  gives  the  explicit 
answer  of  experience. 

The  front  section  was  smashed  during  road  tests.  Where 
it  was  crumpled,  the  dents  were  pushed  into  contour  and 
recoated  with  a  thick  paste  of  the  laminating  resin.  A  16" 
fracture  was  corrected  by  laminating  three  layers  of  Fiber- 
glas  to  the  underside.  The  tear  was  filled  with  paste  and  a 
cure  in  sunshine  effected  in  10  min.  Surface  grinding 
smoothed  the  rupture,  after  which  the  piece  was  repainted. 

Time  for  the  repair  was  2'/3  hr.  Cost  was  $27,  as  com- 
pared with  an  estimated  $60  if  the  part  had  been  of  metal. 
Should  it  have  been  necessary  to  replace  the  entire  front 
section,  the  cost  would  have  been  but  $80. 

Many  Advantages 

Other  advantages  pointed  out  by  W.  B.  Goldsworthy. 
president  of  Industrial  Plastics  Corp.,  Gardcna,  Calif.,  which 
fabricated  the  two  body  parts  and  performed  the  repair,  are 
that  the  parts  are  quickly  and  easily.  .1-  well  as  economically, 
formed.  They  possess  high  strength  with  low  weight  ratio, 


have  dimensional  stability,  are  highly  impact  resistant  and 
are  not  subject  to  crystallization  or  fatigue  as  with  metal. 
In  addition,  they  are  resistant  to  moisture  absorption,  weath- 
ering and  attack  by  ultra  violet  ray. 

As  they  are  of  one  piece,  there  are  no  riveted  fender  or 
other  sections  to  work  loose.  The  usual  rattles  of  approxi- 
mately 15  different  metal  stampings  are  eliminated. 

Ten  work  days  were  required  to  fabricate  the  two  large 
prototype  parts,  with  eight  of  them  given  to  production  of 
the  female  plaster  molds  in  which  they  were  shaped.  These 
were  made  from  two  full-scale  plaster  mockups  provided 
by  the  designer.  Both  mockups  were  made  to  outside  mold 
lines,  which  facilitated  and  speeded  the  fabrication  of  the 
dies. 

Resin,  into  which  a  sunshine-cure  catalyst  had  been  mixed, 
was  applied  by  paddle  and  brush  to  the  Fiberglas  ply.  \Yhen 
thoroughly  impregnated,  these  sheets  were  placed  in  the 
molds  and  hand-pressed  to  contour. 

Each  layer  of  laminate  was  given  20  min  to  cure  in  warm 
sunlight,  after  which  the  runs  were  sanded  and  buffed  to 
provide  even  surfaces  for  the  following  ply. 

In  this  manner  four  .015"  layers  of  laminate  produced 
parts  .070"  thick.  Holes  for  lamps,  locks  and  license  plate 
brackets  were  routed  with  a  band  saw. 

Metal  hinge  bars  wore  laminated  into  the  plastics  struc- 
ture, thereby  providing  high  strength,  and  eliminating  riv- 
et-, or  \*At-.  which  trnil  to  wear  loose  and  become  noi 
rough  highway^. 

The  resin  was  clear,  which  ii<-c.---it;»tcd  coating  with  or- 
dinary automobile  lacquer.  (ioliUworthy  said  that  -ImuM 
the  prototype  lead  to  mass  production  a  colored  resin  may 
.  As  an  alternative,  a  clear  resin  would  be  colored 
i  i  .'iitinutd  on  page  69) 


()( TOHKK  1946 


MEYERCORD  DECAIS 

offer  the  added  sales-appealing 

CHARM 

that   attracts   more 

CUSTOMERS 

to  your  products  —  at  low  cost! 


Attractively  decorated  merchandise  produces 
more  consumer  sales  volume  .  .  .  with  greater 
profit  to  maker  and  dealer  alike.  Decorate  with 
durable  Meyercord  Decals  at  a  fraction  of  hand- 
painting  time  and  cost.  Manufacturers  are  in- 
vited to  submit  samples  for  expert  deco- 
rating recommendations. 


I 


b?=/&5£& 

w*  ^2ik%. 


Ex*cutiv*t:  Send  for  this  new 
D«col    Decoration    Catalog. 
(Firm  letterheads,  pleas*) 


Stock  designs  are  avail- 
able for  immediate  delivery. 
Exclusive  designs  can  be  pro- 
duced to  specifications  on  request. 
Address  inquiries  to  Dept.84-.10 


OCTOBER  1946 


PLASTICS 


51 


Button*  and  novelties,  beautiful  in  color  and  finish,  are  made  of  casein  by  the  American  Plastics  Corp. 

Know  Your  Caseins 

Part  I.    Discussion   of  chemical  structure  and  preparation   of 
casein/  development  of  casein  plastics  in  Germany  and  England 


e>ljr. 


.  brother 


PLASTICS  made  from  casein  are  used  for  most  coat 
and  suit  buttons  today.  Casein  bonds  much  plywood  and 
is  used  in  the  production  of  the  best  coated  papers.  Yet  few 
users  and  a  small  proportion  of  the  general  public  know 
what  casein  is  and  where  it  comes  from. 

The  milk  of  mammals  is  designed  by  nature  to  contain 
all  the  food  elements  in  readily  assimilable  form  essential 
to  the  proper  growth  of  infants  of  the  species.  Amonp  these 
elements,  the  "body  builders"  are  the  proteins  albumin, 
globulin,  and  casein,  the  last  being  present  in  largest 
amount.  Average  cow's  milk  contains  about  three  per  cent 
casein.  Albumin  and  globulin  are  water  soluble,  while  casein 
is  water  insoluble,  existing  in  fresh  sweet  milk  in  very 
finely  dispersed  condition,  somewhat  like  the  fine  carbon 
particles  in  smoke.  Upon  souring  of  the  milk,  this  condition 
changes,  the  particles  of  casein  aggregating  to  form  clots 
or  curds,  which  separate  from  the  liquid  as  solid.  Thu-. 
"cottage  cheese"  is  essentially  casein  in  a  form  familiar  to 
everyone. 

Just  as  cow's  milk  is  predominantly  the  quantity  milk  of 
commerce  in-  this  country,  so  casein  derived  from  cow's 
milk  is  the  industrial  casein  and  is  generally  so  understood. 
Vegetable  proteins  are  sometimes  incorrectly  called  caseins. 
As  mentioned  above,  casein  is  a  protein  or,  more  correctly, 
a  mixture  of  proteins.  Proteins  are  among  the  most  com- 
plex of  the  organic  or  carbon  compounds,  and  casein  is 
among  the  more  complex  proteins,  known  as  phospho-pro- 
teins.  Until  recently,  it  was  considered  a  single  more-or-lcss 
homogeneous  compound,  but  it  is  now  known  to  consist  of 


two  or  more  different  proteins  of  about  the  same  solubility, 
so  they  coagulate,  dissolve,  and  react  in  general  together  as 
though  a  single  compound. 

The  proteins  are  so  complicated  in  structure  and  reac- 
tions that  it  has  been  possible  to  begin  to  get  something 
like  a  reasonable  picture  of  them  only  recently  by  applica- 
tion of  such  modern  techniques  as  X-ray  diffraction,  sedi- 
mentation by  the  ultracentrifuge,  ionic  mobilities  by  electro- 
phoresis,  electron  microscopic  examination,  and  the  like.  And 
on  the  interpretation  of  this  modern  data  the  expert--  are 
not  always  in  agreement.  For  the  present  treatment  the 
highly  technical  aspects  of  the  subject  need  not  be  pre- 
sented ;  instead,  an  effort  will  be  made  to  give  a  compara- 
tively simple  picture  understandable  to  everyone.  This  will 
be  an  over-simplification,  but  it  is  justified  if  it  enables 
readers  who  lack  the  background  to  follow  more  technical 
discussions  to  get  a  reasonably  clear  picture  of  casein  and 
thus  be  able  to  understand  its  industrial  development  and  to 
appreciate  its  strong  and  weak  characteristics  in  industn.il 
application-. 

The  units  or  "building  blocks"  for  casein,  as  for  all  pro- 
teins, are  the  alpha  amino  acids.  These  are  compounds  in 
which  the  four  bonds  of  one  of  the  carbon  atoms  are  at- 
tached to  a  — COOH  group  (organic  acid),  a  — NHi  group 
(organic  ammonia),  a  — H  (hydrogen),  and  any  one  of 
some  twenty-odd  groups,  including  another  acid  group,  an- 
other ammonia  (amine),  hydroxyl,  phenol,  etc.  Reaction 
between  the  acid  group  of  one  amino  acid  and  the  alpha 
amino  group  on  another,  repeated  over  and  over,  is  the 


P  I.  AST  I  <  S 


OCTOBER  1916 


liechanism  by  which  the  protein  molecule  is  built  up.  The 
leaction  between  an  organic  acid  and  an  organic  ammonia 
lamine)  produces  an  amide  — CO — NH — ;  hence  proteins 
Inay  be  considered  polyamides,  although  they  are  usually 
I  ailed  polypeptides.  The  reaction  producing  the  "backbone" 
lif  the  protein  chain  molecule  taking  place  on  one  end  of 
Jhe  amino  acids  leaves  the  other  ends  extended  as  side- 
l-hains  around  the  backbone,  and  in  these  are  found  the 
reactive  portion  of  the  protein  molecule. 

The  normal  relaxed  condition  of  a  chain  or  string  is  not 
extended  linearly,  but  rather  irregularly  curled  and  twisted, 
unless  it  is  held  by  the  imposition  of  a  force.  The  same  ap- 
pears true  of  the  submicroscopic  protein  molecules.  Al- 
r.hough  these  are  chains,  they  appear  not  to  have  linear  ori- 
jntation  unless  bonds  or  attractions  exist  between  different 
:hains  tending  to  hold  them  more  or  less  extended.  This 
:ondition  appears  to  exist  in  such  proteins  as  hair,  wool, 
rtoofs,  claws,  feathers,  and  horn.  These  are  known  as  fi- 
arous  proteins  and  are  the  most  stable  and  resistant  to 
change  and  reaction  of  all  proteins.  In  the  absence  of  inter- 
chain bonding,  there  appears  to  be  a  certain  amount  of 
intrachain  bonding  or  attraction  between  the  reactive  groups 
in  the  side  chains  of  the  molecule  itself,  which  tends  to  hold 
or  even,  perhaps,  intensify  the  balled-tip,  snarled  condition 
of  the  chain.  These  protein  molecules  appear  by  physical 
chemical  measurements  to  be  in  roughly  spherical  or  globu- 
ar  shape  and  are  accordingly  known  as  globular  or  cor- 
puscular proteins.  They  are  not  as  stable  or  as  resistant 
:o  change  or  reaction  as  the  fibrous  proteins  are.  They 
dissolve  readily  in  alkaline,  salt  water,  and  acid  solutions, 
and  some  are  even  soluble  in  neutral  water.  Casein  and 
other  food  proteins,  such  as  vegetable  and  egg  proteins,  are 
globular  proteins. 

'reparation  of  Casein 

Casein  is  prepared  by  agglomeration  of  the  particles  in 
milk  and  separation  from  the  soluble  constituents  by  filtra- 
ion  and  washing.  It  has  been  noted  that  the  simple  souring 
of  milk  produces  this  result,  which  is  due  to  the  formation  of 
actic  acid  by  the  action  of  bacteria  upon  the  lactose,  or  milk 
sugar.  The  addition  of  lactic  acid,  or  any  other  acid  such  as 
muriatic,  sulphuric,  acetic,  etc.,  to  fresh  milk  will  cause  the 
:oagulation  of  the  casein  in  curds.  The  action  of  the  enzyme 
•ennin,  obtained  from  the  lining  of  calves'  stomachs,  upon 
sweet  fresh  milk  causes  the  casein  to  coagulate  in  a  firm 
clot  or  jelly,  which  on  aging  gradually  toughens  and  exudes 
whey.  This  can  be  speeded  by  the  addition  of  calcium 
chloride  to  the  milk  after  the  addition  of  the  enzyme.  A 
popular  milk  dessert,  known  as  "junket,"  used  to  be  pre- 
pared in  this  way,  and  rennin  coagulated  casein  is  the  base 
for  the  preparation  of  some  types  of  cheese. 

Any  fat  present  in  the  milk  will  be  present  in  the  coagu- 
lum,  however  formed;  hence  skim  milk,  as  fat-free  as  pos- 
sible, is  always  used  for  industrial,  non-food  casein  produc- 
tion. The  other  constituents  of  milk — lactose,  albumin,  glob- 
ulin and  minerals,  with  the  exception  of  rennin-coagulated 
casein,  as  will  be  shown — are  water  soluble,  so  remain  in 
the  whey  if  the  coagulation  is  properly  done  and  the  curd 
carefully  washed.  It  would  appear  that  a  product  of  reason- 
able purity  and  good  uniformity  could  be  expected  on  large 
scale  as  well  as  laboratory  scale  of  preparation. 

This  has  not  been  generally  true  in  the  past  for  a  very 
good  and  readily  appreciated  reason.  It  has  been  noted  that 
whole  milk  contains  an  average  of  about  three  percent  case- 
in. This  figure  will  be  slightly  higher  in  skim  milk,  but  it 
is  still  much  too  low  to  make  the  collection  and  transporta- 
tion of  such  a  high  proportion  of  dead  weight  water  eco- 
nomically feasible  when  scattered  through  the  country  on 
small  farms.  The  farmers  were  shown  how  to  coagulate 
the  casein  in  their  skim  milk  with  acid,  these  coagula  were 


picked  up  periodically  and  brought  to  central  processing 
plants  and  processed  to  casein,  but  the  products  under  these 
conditions  could  not  be  expected  to  be  uniform  and  they 
were  not.  During  this  period,  an  Argentine  self-soured 
casein  was  imported  and,  although  it  left  much  to  be  desired, 
it  was  reasonably  uniform,  so  it  came  to  be  the  standard  in 
many  industries  using  casein  solutions.  The  domestic  picture 
is  much  changed  for  the  better  today  with  the  many  large 
milk  processing  plants,  and  the  quality  and  uniformity  of 
caseins  produced  are  in  general  quite  satisfactory. 

Caseins  are  named  for  the  coagulant  used  or  the  method 
of  preparation.  Thus,  a  casein  resulting  from  muriatic  acid 
coagulation  is  called  muriatic  casein;  from  sulphuric  acid, 
sulphuric  casein;  from  natural  souring  of  the  milk,  self- 
soured  or  lactic  casein;  from  rennin,  rennet  casein,  and  it" 
made  by  the  grain  curd  method,  a  modification  of  the  muri- 
atic acid  treatment,  grain  curd  casein.  In  addition,  a  casein 
prepared  from  buttermilk  is  so  named,  because  although  the 
casein  itself  is  a  self-soured  or  lactic  casein,  it  is  usually 
contaminated  with  considerably  more  butter  fat  than  the 
regular  process  lactic  casein,  making  it,  for  some  applica- 
tions, somewhat  less  desirable. 

Difference  Between  Various  Caseins 

The  greatest  difference  between  these  caseins  is  between 
the  acid  coagulated,  as  a  group,  and  the  rennet  casein,  as 
would  be  expected.  The  acid  caseins  are  all  readily  soluble 
in  alkaline  water  solutions  and  have  comparatively  low  ash 
content,  two  percent  or  less,  while  rennet  casein  is  soluble 
only  with  considerable  difficulty  and  has  an  ash  content  of 
around  seven  and  a  half  percent,  which  analyses  have  shown 
to  be  almost  entirely  calcium  or  lime  phosphate.  Rennet 
casein,  therefore,  would  not  be  recommended  for  applica- 
tions requiring  solutions  of  casein.  Its  principal  application, 
as  will  be  shown,  is  in  the  preparation  of  plastics,  where  it  is 
processed  entirely  in  the  solid  state.  The  acid  caseins  find 
wide  applications  from  alkaline  water  solutions,  for  which 
they  are  well  suited.  There  appears  to  be  some  difference  in 
viscosities  or  "body"  of  solutions  made  from  lactic  or  from 
the  other  acid  caseins,  but  it  remains  to  be  demonstrated 
whether  this  is  an  actual  difference  or  one  such  as  ap- 
peared to  exist  between  sulphuric  and  muriatic  caseins  and 
which  was  found  to  be  a  difference  caused  by  mineral  con- 
stituents, as  shown  by  ash  analyses,  rather  than  by  any 
difference  resulting  from  the  acid  used  in  coagulation.  It 
should  be  constantly  remembered  that  these  caseins  are  ex- 
(Continued  on  page  94) 

Casein  coagulation  and  treatment  unit  at  Hercules  Powder  Co. 


OCTOBER  1946 


PLASTICS 


53 


Components  of  high  frequency  product!,  mad*  oi  "Textolite  1422"  by  Industrial  Products  Co..  evidence  adaptability  of  material 

"Textolite"  Offers 

Insulating  Advantages 


UNUSUAL  heat  resistance,  and  machinability  to  close 
tolerances,  are  among  qualities  listed  for  Textolite 
1422,  a  new  cast  plastics  announced  by  the  Plastics  Divisions 
of  General  Electric  Co.,  Pittsfield,  Mass.  These  character- 
istics, say  G-E  chemists,  make  the  new  material  particularly 
adaptable  for  use  as  an  insulator  in  electrical  connectors  and, 
with  its  other  attributes,  in  manufacture  of  television,  fre- 
quency-modulation radio  and  radar  sets,  and  in  many  other 
ultra  high-frequency  insulating  applications. 

Textolite  1422  possesses  a  very  low  power  factor,  with 
;m  AS'IM  distortion  of  105°  to  113°  C,  and,  according  to  its 
manufacturer,  can  be  used  in  many  fields  where  compression 
and  injection  molded  plastics  are  not  sufficiently  suitable 
because  of  close  tolerance  requirements,  or  do  not  have 
the  necessary  combination  of  heat  resistance  and  electrical 
properties.  The  material  is  also  applicable  to  small  quan- 
tity production,  and  machines  readily  enough  to  be  adapt- 
.ililr  to  automatic  and  semi-automatic  fabricating  equipment. 

Tests  of  this  plastics  material  are  said  to  have  indicated 
that  under  the  light  loads  commonly  encountered  in  con- 
nector assemblies,  it  will  hold  its  shape  up  to  a  temperature 
of  200°  C  and.  when  fully  loaded,  will  surpass  the  highest 
operating  temperatures  recommended  for  R(i  type  coaxial 
cables.  At  this  temperature,  the  material  does  not  flow,  but 
becomes  flexible,  returns  to  normal  rigidity  when  cool. 

The  use  of  Textolite  1422  is  recommended  by  the  ( icneral 
Klcctric  (  o.  Tor  structural  components  in  high-frequency 
equipment  where  the  lowest  power  factor  is  required  and 
where  operating  temperatures  prevent  using  polystyrene. 

A  dielectric  constant  at  3000  me  of  2.4  to  2.5,  and  a  power 


Possibilities  in  a  variety  of 
insulating  applications  are 
seen  for  new  cast  plastics 

factor  at  3000  me  of  0.0006  to  0.0009,  are  characteristics 
which,  in  addition  to  its  heat  resistance,  provide  this  plastics 
with  application  potentialities  for  connector  beads,  ultra- 
high  frequency  antennae,  oscillator  coils,  stand-off  insulators 
and  rigid  coaxial  spacers. 

In  certain  uses  where  the  finished  product  must  be  able  t< 
withstand  considerable  strain  and  abuse  under  severe  service 
conditions,  the  physical  properties  of  the  new  material  art 
s.-ud  to  render  it  eminently  suitable.  It  has  a  specific  gravity 
of  1.045  to  1.050;  tensile  strength  of  8000  to  10.000  JIM; 
flexural  strength,  15,000  to  18,000  psi  (ASTM-D638- 
42T)  ;  compressive  strength,  18,500  to  19.000  psi  (ASTM- 
D649-42T) ;  impact  strength,  0.25  to  0.35  (ASTM-D256- 
43T)  ;  and  Rockwell  hardness.  H -scale  of  68  to  72.  \\  .itei 
absorption  (ASTM-D570-42),  less  than  0.005%. 

It  is  described  as  being  unaffected  by  mineral  acids,  alka- 
lies, alcohol,  aliphatic  hydrocarbons,  or  mineral  oil.  Slighl 
swelling  is  produced  by  chlorinated  hydrocarbons  and 
ketones,  aromatic  hydrocarlxms  causing  ^ir.iicr  swelling, 

Other  possible  uses  for  Tcxtolite-1422  arc  suggested  by 
its  chemical  inertness  which  may  make  it  applicable  for  in- 
spection w  imlott  s  (in  machinery  and  chemical  equipment 
rollers  for  plating,  tanks,  or  for  electrode  suppoi  t  si 


54 


FLAfSTiCS 


OCTOBER  1946 


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The  How  and  Why 
of  Mechanical  Testing1 


Shape  oi  specimen,  moisture  content,  temperature,  speed 
of  applying   pull,   are   factors  affecting   tensile   strength 


/?       /    A     AfL    / 

\^jerara  _/T.  ^^rlberl 

Salet  and  Development  Engineer 

National  Vulcaniied   Fibre  Co. 


IN  SKI.K<  I  ING  plastics  for  the  manufacture  of  a  product, 
one  of  the  first  considerations  is  its  strength.  This  is 
usually  of  the  greatest  importance  because  many  plastics  of 
varying  properties  arc  available  and  there  is  usually  one 
which  is  Ix-st  suited  for  the  application.  Many  plastics 
possess  excellent  mechanical  properties,  fully  comparable  to 
tho~e  of  other  matt-rials,  which  allow  them  to  l>c  used  a- 
structural  parts  where  the  greatest  of  mechanical  strengths 
are  required.  The  purpose  of  this  article  is  to  discuss  the 
significance  of  the  various  mechanical  properties  and  the 
test  methods  for  measuring  them. 

Tensile  strength  is  a  measure  of  how  much  pull  can  IK' 
exerted  on  a  solid  material  Ix-fore  it  breaks.     It  is  deter- 
mined  by   cl.impini;   a    sjM-cimen    in   the   jaws   of   a    !• 
machine  and  noting  the  numlx-r  of  pounds  of  pull  required 
to  break   it.      I  his  divided  by  the   square   inch  area  of  the 


specimen  at  the  breaking  point  is  the  tensile  strength  of  the 
material.  If  a  1/16"  thick  by  1"  wide  specimen  broke  under 
a  pull  of  620  Ib,  its  tensile  strength  would  be  620  divided 
by  .062,  or  10,000  Ib  per  sq  in  (usually  written  psi). 

The  breaking  pull  of  a  tensile  specimen  is  affected  by  such 
factors  as  the  shape  of  the  specimen,  its  moisture  content, 
speed  of  applying  the  pull,  temperature,  etc.  In  order  to 
eliminate  variations  due  to  these  numerous  factors,  the 
tensile  test,  as  well  as  all  other  tests,  is  made  according  to 
a  standard  procedure.  Such  standards  are  formulated  only 
after  all  factors  that  influence  the  final  results  are  carefully 
considered  by  a  technical  organization  composed  of  both 
plastics  manufacturers  and  users — a  committee  of  the 
American  Society  for  Testing  Materials  (ASTM). 

Tensile  strength  is  easily  tested  and  is  extremely  useful  to 
the  producer  to  control  the  quality  of  his  finished  product 
and  to  determine  the  uniformity  of  his  raw  materials.  It 
aKo  serves  to  help  improve  his  manufacturing  processes  so 
as  to  make  higher  quality  products.  The  end-user,  for  his 
part,  can  effectively  use  the  test  to  determine  whether  the 
material  he  is  buying  is  suitable  for  a  given  application,  es- 
pecially now  when  substitute  materials  must  be  used.  Also, 
knowing  the  tensile  strength,  the  designer  can  make  better; 
and  cheaper  products. 

Compressive  Strength 

Compressive  strength  is  a  measure  of  how  much  load  or' 
push  must  be  applied  to  a  material  to  break  it.  This  test  is; 
performed  by  making  an  inch-high  pile-up  of  sheet  speci-j 
metis  1"  by  1"  and  noting  how  many  pounds  of  force  must 
be  applied  before  it  breaks.  The  breaking  or  crushing  load 
in  pounds  divided  by  the  area  of  the  pile-up  in  square  inches 
is  the  compressive  strength  expressed  in  psi. 

This  test  is  especially  useful  when  plastics  designers  are< 
looking  for  a  material  that  would  be  subjected  to  com-! 
pressive  forces  or  loads  as  would  occur,  for  instance,  in, 
furniture  casters  and  artificial  legs. 

A  measure  of  how  much  bending  or  flexing  load  a  plastics 
can  resist  before  it  breaks  is  its  flexural  strength.    This  test  I 
is  made  by  placing  a  bar  specimen  on  two  supports  and 
flexing  it  with  a  force  applied  at  a  point  equidistant  between 
the  supports.    The  flexing  load  is  slowly  increased  at  a  uni- 
form rate  until  the  bar  specimen  breaks.  With  the  breaking 
load  in  pounds,  the  dimensions  of  the  cross  section  of  the] 
bar,  expressed  in  inches,  and  the  number  of  inches  between  , 
the  supports,  the  flexural  strength  is  calculated  by  a  simple  . 
algebraic  formula. 

When  a  plastics  bar  specimen  is  flexed  as  occurs  during 
this  test,  one  surface  is  stretched,  that  is,  put  under  tensile 
-tn-ss.  while  the  other  surface  is  compressed.    The  surface 
of  the  specimen  in  flexure  which  breaks  first  is  the  one  that  | 
is  stretched,  that  is,  the  one  subjected  to  a  pulling  or  tensile 
stress.      In    general,    therefore,    the    tensile    and    flexural 
strengths  are  related.    The  flexural  strength  of  many  plas- 
tu-s  is  usually  about  one  and  three-quarters  to  two  times  as  | 
great  as  their  tensile  strength. 

The  flexural  .strength  test  is  perhaps  made  more 
than  other  mechanical  tests  on  plastics,  chiefly  because  of  ] 
the  ease  of  prcparinp  the  samples  and  the  simple  equipment 
needed  to  make  the  test.    The  producer  of  plastics  relies  on 
it  to  tell  him  how  uniform  his  material  is  from  batch  to 
hatch  and  what  the  proper  cure  of  a  new  formulation  should 


.-,6 


I'l.ASTICS 


OCTOHKR  1916 


14,000 


"'000 


12,000 


Uj 

1 

<0 


11,000 


1 


•  10,000 


01  234 

SPEED  OF  LOAD  APPLICATION  (IN./M 

Variation  of  the  flexuial  strengths  of  polystyrene 


S,v, 


In  determining  impact  strength,  by  the  Izod  method, 
the  specimen  is  clamped  at  one  end  in  a  vertical 
position,  with  the  hammer  striking  the  exposed  end 


be  to  obtain  the  maximum  strength  from  it.  The  con- 
sumer must  know  the  flexural  strength  of  his  plastics  mate- 
rial so  that  he  can  economically  design  his  product.  There 
are  few  plastics  parts  that  are  not  normally  subjected  to 
bending  stresses. 

The  resistance  of  a  material  to  shock  or  suddenly  applied 
loads  is  its  impact  strength.  A  high  impact  material  rapidly 
equalizes  the  concentrated  stresses  that  it  receives  with  a 
shock  load,  without  breaking.  A  low  impact  strength  mate- 
rial, on  the  other  hand,  is  one  which  breaks  because  it  cannot 
absorb  or  equalize  shock  loads.  It  is  said  to  be  brittle.  The 
impact  strength  test  is  not  made  with  slowly  applied  loads, 
as  are  used  for  the  static  tests  such  as  tensile,  compressive 
and  flexural,  but  instead  by  a  rapid  blow  from  a  pendulum 
type  hammer.  Impact  strength  is  expressed  mathematically 
as  foot-pounds  of  energy  (work)  required  to  break  the  bar 
specimen  divided  by  the  width  of  the  bar. 


10 

9 
V 

?  a 


0         2         4          6          8          10        12        14         16          18        20 
MOISTURE  CONTENT  (%) 

Variation  of  impact  strength  of  vulcanized  fibre  plastics 


There  are  two  recognized  methods  for  determining  the 
impact  strength  of  solid  materials,  namely,  Izod  (canti- 
lever) and  Charpy  (simple  beam).  In  the  Izod  method  the 
specimen  is  mounted  as  a  cantilever,  that  is,  clamped  at  one 
end  in  a  vertical  position,  with  the  hammer  striking  the  ex- 
posed end.  In  the  Charpy  test  the  bar  specimen  is  placed  in 
a  horizontal  position  against  end  supports  and  is  struck  by 
the  hammer  at  its  center.  There  is  no  definite  correlation 
between  Izod  and  Charpy  impact  strength  values  made  on 
specimens  of  the  same  material. 

Shock  Tests  for  Laminates 

Impact  tests  of  laminated  sheet  materials  are  made  with 
the  hammer  striking  the  specimen  either  flatwise  (perpen- 
dicular to  the  laminations)  or  edgewise  (parallel  to  the  lam- 
inations). In  the  latter  case,  the  sheet  test  bar  is  usually 
notched,  that  is,  a  groove  is  filed  or  machined  in  the  bar  at 
a  specified  place.  The  notch  combines  with  the  speed  of  the 
striking  hammer  to  produce  a  concentration  of  stress.  For 
a  notched  bar  specimen  the  impact  strength  is  expressed  as 
"foot-pounds  per  inch  of  notch." 

It  is  interesting  to  note  that  there  is  no  known  relation- 
ship between  static  and  impact  strength  of  plastics.  Two 
materials,  for  instance,  may  have  approximate  values  of 
static  strengths,  such  as  tensile,  flexural,  and  compression, 
but  entirely  different  impact  strengths.  This  is  well  illus- 
trated by  comparing  the  properties  of  two  grades  of  lami- 
nated phenolics,  Grade  X  (paper  base)  and  Grade  C  (cloth 
base.)  The  static  test  properties  of  both  grades  are  almost 
identical,  whereas  the  impact  strength  of  one  is  five  times 
that  of  the  other. 

Since  impact  is  a  measure  of  shock  resistance,  this  test  is 
made  on  plastics  materials  intended  for  use  on  parts  that 
will  be  struck,  dropped,  or  otherwise  given  shock  stresses. 
Typical  applications  are  the  telephone  receiver  (which  often 
is  dropped  on  the  floor),  insulating  parts  of  switches,  and 
gears  whose  teeth  are  subjected  to  severe  shock  stresses 
when  their  driving  motors  suddenly  start. 

A  plastics  that  is  considered  for  an  application  in  which 
it  will  be  subjected  to  heat  should  not  soften  or  distort  at 
the  operating  temperatures  required  or  generated.  The  heat 
distortion  point  is  determined  by  noting  the  temperature  at 
which  a  bar  specimen  resting  on  supports  4"  apart,  with  a 
(Continued  on  page  69) 


OCTOBER  1946 


PLASTICS 


57 


Ladies  Apparel  Adopts  Plastics 


"Syntilile"  pinafore,  durable,  diaphanous,  eye-catching, 
gives  an  idea  of  plastics'  possibilities  in  dress  design 


e 


, 


WHAT  ARE  believed  to  be  the  first  sports  dresses  ever 
manufactured  entirely  from  vinyl  film,  were  displayed 
by  A!ir<-  nf  <  'alifornia  at  a  recent  fashion  show  in  San  Fran- 
cfoco. 

At  the  present  time  these  garments  are  still  showpieces, 
since  a  great  deal  of  development  work  re-mains  to  be  done 
before  full-scale  production  is  practical.  The  widespread 
interest  shown  in  this  innovation,  by  the  public  and  by  the 
garment  trade,  however,  indicates  that  developments  will 
undoubtedly  continue  until  an  all  plastics  wardroti. 
reality. 

(  )iw   of   the   largest   dress   manufacturers   on   the   Pacific 

ami  serving  a  national  market,  Alice  of  California 
decided  t"  investigate  tin-  possibilities  nf  plastics  films  bc- 

thcy  offered  a   source  of   fresh,   new   styles  for  the 

•ilar  i-niistimer  demand  met  by  this  manufacturer. 
'I  he  firm  is  a  volume  producer  I  JO  .(MM)  units  per  \- 

tial  ami  sports  apparel  designed  for  California  wear, 
and  its  fashion*  etnphasi/e  informality.  Company  officials 
felt  that  all  plastics  fabrics  would  tit  into  this  picture,  since 


Attractive  dresses  of  vinyl  film 
show  promise  of  wide  popularity 
\vith  both  designer  and  wearer 


they  are  colorful,  easy  to  keep  clean,  and  will  shed  water. 
Transparency  was  considered  an  advantage,  making  it 
possible  to  produce  varied  effects  when  worn  over  colored 
or  patterned  slips,  enhancing  color  and  style  of  the  garment 
worn  beneath,  besides  contributing  to  the  "bare  look"  which 
ha-  Income  fashionable. 

When  the  designers  obtained  some  samples  to  work  with, 
other  advantages  came  to  light.  Probably  of  first  importance 
is  the  fact  that  plastics  films  have  no  "grain"  (warp  and 
weft)  which  is  characteristic  of  woven  material.  This  means 
a  minimum  of  waste  in  cutting  patterns,  since  pieces  of  any 
shape  can  be  cut  from  the  yardage  in  any  direction.  Inas- 
much as  there  are  no  threads,  plastics  fabrics  do  not  ravel, 
which  makes  hemming  unnecessary.  The  films  were  also 
found  to  be  very  strong,  stretching  under  strain  but  re- 
turning to  their  original  shape.  They  lie  flat  without  i 
ing — a  factor  as  important  to  the  designer  as  to  the  <] 
buyer.  The  all-plastics  fabrics  gather  easily  and  drape 
beautifully,  and  the  designers  had  no  difficulty  in  assembling 
them  with  other  material. 

Two  of  the  garments  modeled  were  fabricated  by  sewing 
with  conventional  equipment.  Seams  are  tight,  even  and 
strong.  The  experience  of  the  operators  indicates,  however, 
that  the  plastics  materials  available  at  present  do  not  lend 
themselves  to  commercial  dress  production  by  this  method. 
The  fabrics  did  not  go  smoothly  through  the  machines. 
Trouble  in  the  form  of  softening  and  sticking  was  en- 
countered at  the  pressure  foot  and  where  the  material 
passes  close  to  a  lamp  used  to  light  the  working  area.  This 
was  overcome  by  increasing  the  distance  between  lamp  and 
work  and  reducing  the  speed  of  operation.  While  the 
adjustments  are  not  difficult,  any  appreciable  increase  in 
completion  time  brings  costs  to  above  acceptable  limits. 

The  Singer  Sewing  Machine  Co.  has  developed  a  high- 
frei|iiency  electronic  bonding  machine  which  might  do  much 
to  overcome  this  difficulty.  Built  and  operated  on  much 
the  same  principle  as  a  sewing  machine,  it  forms  an  almost 
invisible  seam  at  speeds  up  to  thirty  feet  a  minute.  This 
development,  incidentally,  is  one  of  the  strongest  indications 
of  the  tremendous  increase  expected  in  the  use  of  pi 
fabrics. 

The  other  major  drawbacks  of  all-plastics  d: 
observed  by  the  company,  are  problems  for  the  raw  material 
suppliers  to  solve.    The  materials  display  a  tender 
adhere  to  a  wearer's  skin  after  being  worn  for  a  few  hours. 
They  do  not  permit  air  circulation,  and  will  produce  .• 
ing  of  suffocation  unless  designed  to  allow  plenty  of  venti- 
lation,    l-'or  easier  fabrication  ami  to  make  them  pi. 
for  wear  under  all  normal  conditions,   the   firm  lx  i 
that    the    films    should    remain    stable    over   a   temperature 
range  wider  than  that  now  provided. 

The   creations   exhibited    nevertheless    indicate    that    the 

potentialities   of   vinyl   films    in   the   apparel   field   an    icady 

for   expansion.     These    styles    were    carefully    designed    to 

ilj/e   on    the   unique    features   of   plastics   and    to 

i,-    for    their    present    limitations.      \    lacy  ap|« 

pinafore  manufactured  from  .Vywff/f/i-  is  a  particularly  good 

(Continued  on  page  94) 


58 


PLASTICS 


(MTOBKK 


I 


DO  ^°u 


Ytavea 


;tV°u 


d\V*c 
-  \trt° 


OUR  ORGANIZATION  WILL 


TO  SOLVE 


PROBLEMS  iN 


We  invite  you 

to  use  the  facilities  of  the 

INTERNATIONAL  PLASTIC  HARMONICA  CORP 

makers  of  the  famous  MAGNUS 
all-plastic  harmonica 


INTERNATIONAL  PLASTIC  HARMONICA  CORPORATION  •  44  DICKERSON  STREET  •  NEWARK  4,  N.  J. 
OCTOBER  1946  PLASTICS  59 


f. 


,.  rang*  ol 

»«' 

•  -ceu  U  us . 
v»ign  on  one  «h««t  ot  the  . 

>heet 

natvd  ov*:  • 

• 


• 


- 

]ackei< 

clothesline  mad 
sogprop). 


ored  frames  of 
protective  eye  masks  made  by  Standard  Safety 
Equipment  Co.  ore  of  injection  molded  cellulose 
acetate.  Adjustable  headband  is  also  ol  plastics 


injection  molded  cellulose  acetate  section*  are 
used  by  Tbs  Emeloid  Co.,  inc.,  In  a  novel  appli- 
cation to  iotra^wastebaskets  and  magazine  racks, 
which  combine  useful  and  decorative  qualities 

Colorful  plastics  "Veiofiim"  produced  by  Firestone 
Tire  &  Rubber  Co.  is  fashioned  into  a  novelty,  rain 
proof  hat  with  streamers  which  can  be  released  tc 
protect  coiffure  and  shoulder*  from  sudden  shower* 

An  ingenious  new-type  garment  hanger  which  can 
bo  adjusted  to  size,  thus  meeting  individual  re 
quiremeats,  utilize*  phenolic  plastics  combine 
a  light  weight  and  conserv 


Walking1 

Plastics  ''shoe  ventilators" 
have  combatted  the  humidity 
usually  generated  inside 
shoes  and  its  resultant  ills 


Ljrant 


Various  developments  ol  "Vent-O-Sole" 
include  "Saran"  plies  bound  in  by  cot- 
ton; plies  stitched  along  edges;  plies 
with  nylon,  heat-sealed:  and  finally. 
"Saran"  plies  heat-sealed  along  edges 


FOOT  comfort  is  a  factor  in  the  comfort  of  the  entire 
human  body,  and  has  a  definite  effect  on  the  efficiency, 
well-being  and  nerves  of  the  individual.  Anything  that 
adds  to  foot  comfort  is  accordingly  of  interest  to  most  peo- 
ple— particularly  to  those  in  the  industrial  field,  or  to  any 
persons  who  must  be  on  their  feet  a  great  part  of  the  time. 

In  this  connection,  the  versatility  of  plastics  has  again 
been  demonstrated  in  the  form  of  a  "shoe  ventilator,"  made 
of  Saran  (vinylidene  chloride).  Originally  developed  for 
Army  use  during  the  war,  by  Frank  Dale,  these  shoe 
ventilators  were  worn  by  thousands  of  American  soldiers, 
in  jungle  boots  and  other  military  footwear. 

Illustration  of  the  value  of  this  plastics  ventilator  for 
civilian  use,  as  well,  is  provided  in  the  recent  experience 
of  an  industrial  plant  in  the  middle-Atlantic  States,  where 
acid  seepage  from  walls  and  floors  (due  to  the  nature  of 
the  plant's  operations)  had  resulted  in  foot  troubles  for  the 
workers,  with  a  consequent  high  rate  of  absenteeism.  This 
seepage  penetrated  the  best  and  toughest  of  safety  shoes. 
The  use  of  rubber  overshoes  and  boots  was  tried,  but  this 
footwear  eventually  deteriorated  in  presence  of  the  acid, 
and,  in  addition,  contributed  to  greater  dampness  of  the 
workers'  feet,  causing  more  foot  ailments  and  increased 
absenteeism. 

Seeking  some  means  of  alleviating  the  condition,  which 
.teemed  about  to  cause  a  production  crisis,  the  company 
found  that  the  plastics  shoe  ventilator*  were  bring  intro- 


duced to  the  market  through  the  Dale  Vent-O-Sole  Co., 
which  had  been  organized  by  Frank  Dale.  A  rush  order 
resulted  in  the  company's  being  quickly  supplied  with  a 
quantity  of  the  civilian-type  ventilators  sufficient  to  equip 
the  work  shoes  of  all  of  the  plant's  employees.  Within  a 
matter  of  days,  the  company  reported  that  the  foot  ail- 
ineiit*  of  its  workers  had  disappeared.  And  although  the 
acid-seepage  conditions  have  since  been  remedied,  the  shoe 
ventilators  have  been  adopted  by  the  plant  as  standard 
equipment  for  its  workers'  shoes. 

Advantages  Resulting 

The  plant  mentioned,  like  others,  has  also  found  that  a 
number  of  corollary  advantages,  besides  decrease  of  ab- 
senteeism, result  from  correction  of  the  actual  foot  ills — 
such  advantages  as  less  fatigue  and  nervous  irritability 
among  workers,  etc. 

The  original  development  of  this  shoe  ventilator,  which 
is  to  be  known  as  Dale  l'ent-O-Sole,  was  begun  early  in 
the  war.  Athlete's  foot,  blisters,  and  kindred  foot  ailments. 
all  traceable  to  insufficient  air  within  the  >hoos  of  trainees 
at  Army  camps,  were  found  to  be  a  major  cause  of  incapac- 
it;iti"ti  of  tluiM-  trainees.  It  accordingly  became  impera- 
tive to  tinil  >ome  means  of  protecting  soldiers'  feet  from 
the  rubbing  of  the  leather  in  heavy  Army  shoe*  anil  boots, 
which  chafed  and  irritated  feet  damp  with  perspiration.  It 
has  been  saiil  that  the  rubber-soled  "jungle  boot"  alone  was 


PLASTICS 


OCTOBER  1946 


On  Air.. 


responsible  for  incapacitation  of  almost  as  many  men  as 
were  lost  in  combat  during  the  war. 

Dale,  who  at  that  time  was  a  consultant  to  the  Quarter- 
master Corps  on  procurement  of  products  needing  special 
development,  began  work  on  the  problem,  after  making  a 
preliminary  study  of  the  causes  of  the  soldiers'  foot  ail- 
ments; it  was  obvious  that  the  requirement  was  for  some 
method  of  overcoming  the  humidity  usually  generated  inside 
shoes. 

His  first  efforts  were  with  innersoles  of  horsehair,  tail- 
ored to  fit  inside  the  shoes,  and  porous  enough  to  provide 
at  least  a  modicum  of  air  underneath  the  feet.  Unfor- 
tunately, however,  the  horsehair,  despite  being  rubberized, 
proved  to  have  an  affinity  for  insects. 

Dale  next  investigated  the  merits  of  a  plied-up  innersole 
of  woven  material  having  longitudinal  threads  of  cotton, 
with  cross-threads  of  vinylidene  chloride.  But  while  the 
plastics  strands  proved  effective  in  repelling  moisture,  dirt, 
and  odor,  and  resisting  compression,  the  cotton  strands  re- 
tained too  many  of  the  characteristics  of  all-cotton  inner- 
soles — moisture  absorption  and  consequent  dampness,  odor 
after  continued  wear,  susceptibility  to  contamination  from 
dirt  and  fungi,  and  so  on. 

Plied-up  vinyl  chloride-acetate  woven  fabrics  were  also 
tried  for  the  innersoles,  but  were  discarded  because  the  fila- 
ments proved  too  brittle  under  constant  flexing,  and  the 
heat-sealed  portions  showed  a  tendency  to  separate  too 
quickly. 

Dale's  next  effort  was  with  a  plied-up  innersole  of  six 
layers  of  Lumite  (woven  vinylidene  chloride),  which,  as 
insect  screening,  was  already  being  used  by  the  Army  in 
humid  jungle  areas.  He  experimented  with  a  cotton  fabric 
binder  to  hold  the  layers  in  place,  but  again  found  that  too 
many  of  the  disadvantages  of  the  natural  cotton  fibres  were 
retained  in  the  binder.  The  difficulty  lay  in  finding  some 
means,  other  than  natural-fibre  fabrics  or  thread,  of  hold- 
ing the  plied-up  layers  of  the  all-plastics  innersole  in  place. 

Even  cementing  the  plastics  layers  had  failed ;  water  and 
moisture  broke  or  distorted  the  seals.  Pressing  with  a  hot 
iron  produced  too  compact  a  mass  or,  with  less  heat,  too 
tenuous  a  bond. 

Heat  Scaling 

A  casual  experiment  with  a  match  produced  the  final 
answer.  Dale  held  a  few  pieces  of  the  fabric  together  in 
his  fingers,  then  exposed  the  sides  to  the  flame,  pressing 
them  together  while  still  hot.  When  they  cooled,  an  in- 
tegral bond  between  the  pieces  of  plastics  fabric,  along  the 
edges,  had  resulted.  The  way  was  thus  prepared  for  pro- 
ducing the  all-plastics  innersoles,  on  a  major  scale. 

At  first,  experimental  pairs  of  five  plied-up  layers  of  the 
fabric  were  sealed  with  a  soldering  iron.  Special  machin- 
ery to  speed  production  was  then  developed,  including  click- 
ing machines  to  cut  the  layers  of  fabric,  automatically,  to 
desired  sizes.  Still  another  machine  was  developed  to  cut 
the  fabric  and  seal  the  plies  simultaneously.  Difficulties 
were  encountered  in  use  of  this  machine,  however,  in  a 
tendency  toward  carbonization  of  the  plastics  on  the  cut- 
ting edges. 

Now,  in  the  company's  Brooklyn  plant,  improved  ma- 
chines are  being  used  to  bring  the  edges  of  the  plied-up 
fabric  for  each  innersole  to  their  approximate  softening 
point  of  between  240°  and  280°  F,  then  sealing  them. 

Literally  millions  of  pairs  of  the  innersoles  were  provided 
for  American  troops.  At  one  time  during  the  war,  20,000 


pairs  were  also  supplied  under  Lend-Lease  for  coal  miners 
in  England,  whose  foot  ills  were  crippling  production  of 
vitally  needed  fuel.  So  successful  were  these  ventilators  in 
cutting  down  absenteeism  that  the  English  government 
asked  the  U.  S.  Treasury  Department  for  an  additional 
6,000,000 — an  order  which  could  not  be  filled  due  to  the 
short  supply  of  Saran. 

As  their  use  expands  beyond  the  industrial  market,  to 
sportsmen,  athletes  and,  in  general,  to  people  who  are  on 
their  feet  a  great  deal,  Dale  envisions  a  postwar  America 
walking  literally  "on  air"  with  feet  thereby  protected  in 
the  same  manner  as  those  of  chickens  on  ultra-modern 
poultry  farms.  Keeping  the  feet  of  chickens  off  the  ground 
averts  the  causes  of  99%  of  poultry  diseases.  Similarly,  a 
person  walking  on  the  air  provided  by  the  grids  of  woven, 
contamination-proof  plastics  fabrics  is  protected  from  fungi 
and  other  conditions  which  foster  podiatric  difficulties. 

Protection  for  Indefinite  Periods 

This  theory  is  borne  out  by  tests  conducted  by  the  U.  S. 
Army  Medical  Corps,  in  which  Army  doctors  found  that 
healthy  feet  in  fungi-laden  shoes  will  contract  athlete's  foot 
in  a  few  hours.  When  the  feet  are  protected  by  a  layer  of 
sterile  cloth,  the  affliction  develops  in  just  the  time  required 
for  its  fungi  to  penetrate  the  fabric.  The  plastics  shoe 
ventilators,  however,  are  said  to  protect  the  feet  for  in- 
definite periods  of  time.  Also,  the  constant  ventilation 
which  they  provide  serves  to  ward  off  the  humid  foot  con- 
ditions in  which  fungi  thrive  after  reaching  the  flesh. 

Heretofore,  a  standard  treatment  for  athlete's  foot  has 
(Continued  on  page  97) 


CROSS     SECTION. 
CAN'T     COMPACT. 


Cross  section  oi  plastics  innersole  which  allows  iree 
circulation  oi  air  from  heel  to  toe.  Below,  first  ex- 
periments: cotton  with  filler;  vinyl  and  cotton  surface 
with  cotton  batting  inside,  oilcloth  binder  on  edge; 
vinyl  and  cotton,  without  the  filler  and  cotton  binding 


OCTOBER  1946 


PLASTICS 


63 


J  L    » 
nVBarH  **•*, 


Polyethylene-coated  antenna   parts  make  test   plane   radio   impervious  to  extreme  discharges  (St.  Elmo's  Fir*  in  circles) 


Preventing  Precipitation  Static 


Polyethylene  coatings  applied  to 
external  radio  parts  of  aircraft 
prevent  precipitation  static 


Squeaks  and  screech**  are  barred  Iiom  this  cargo  plane's 
radio  room  by  polyethylene  on  external  wires  and  tubing 


e  .  w. 


, 


OF  NOVEL  interest  is  the  use  of  polyethylene  to  prevent 
precipitation  static  from  interfering  with  the  opera- 
tion of  aircraft  radio  sets.  Whereas  calls  for  plastics  to 
afford  covering  from  rain,  snow,  and  other  of  nature'* 
phenomena  are  commonplace,  in  this  aviation  communica- 
tion equipment  discovery  plastics  has  been  chosen  a*  pro- 
tection not  only  from  the  tangible  eroding  weather  nutter 
but  from  an  unseen  repercussion  of  it. 

Precipitation  static  is  the  disturbance  in  aircraft  radio  ami 
other  communications  equipment  reception  provoked  by 
discharges  of  excess  electricity  which  occur  when  the  plain 
i*  Hying  in  or  near  precipitation  areas.  Heretofore  when 
the  discharges  occurred,  noises  like  the  frying  of  eggs  or 
dumping  of  coal  or  a*he*  were  prominent  in  the  pilot 
phones,  and  the  reception  of  message-  or  -ignaK  would  In- 
hampered  to  such  an  extreme  that  the  radio  might  a-  well 
have  been  turned  off. 

Now,  however,   thanks  to  the   practical   application   oi 
polyethylene,  precipitation  static  di-turhances  are  of  little 
consequence.   Actually,  with  use  of  the  new  synthetic  mate 
rial,  precipitation  static  is  never  cx|wrienced  though  it  IK- 
in  a  (Hitrntial   slate  at  all  time*. 

Polyethylene  will  Ix-  applied  to  all  e\|x>*eil  i.ulio  antenna 


64 


PI.ASTtt'S 


<>(  TOHKK 


m,  easy  My  to 


OUT  of  the  war  has  come  one  bless- 
ing—  a  lesson   in  thrift  for  mil- 
lions of  those  who  never   before  had 
learned  to  save. 

Enrolled  under  the  Payroll  Savings 
Flan  in  thousands  of  factories,  offices, 
and  stores,  over  27  million  American 
wage  earners  were  purchasing  "E" 
Bonds  alone  at  the  rate  of  about  6 
billion  dollars  worth  a  year  by  the  time 
V-J  Day  arrived. 

With  War  Bond  Savings  automati- 
cally deducted  from  their  wages  every 
week,  thrift  was  "painless"  to  these 
wage  earners.  At  the  end  of  the  war, 
many  who  never  before  had  bank  ac- 
counts could  scarcely  believe  the  sav- 
ings they  held. 

The  moral  was  plain  to  most.  Here 
was  a  new,  easy  way  to  save;  one  as 
well  suited  to  the  future  as  to  the  past, 
llesult:  Today,  millions  of  Americans 
are  continuing  to  buy,  through  their 
Payroll  Savings  Plan,  not  War  Bonds, 
but  their  peacetime  equivalent —  U.  S. 
Savings  Bonds. 


From  war  fo  peace!  War  Bonds  are  now 

known  as  U.  S.  Savings  Bonds,  bring  the  same 
high  return— $25  for  every  $18.75  at  maturity. 


Out  of  pay — into  nest  eggs!  A  wage  earner 
can  choose  his  own  figure,  have  it  deducted 
regularly  from  earnings  under  Payroll 
Savings  Plan. 


New  homes  to  own!  Thousands  of  new 
homes,  like  this,  will  be  partially  paid  for 
through  Bonds  wisely  accumulated  during 
the  next  five  to  ten  years. 


Keeping  cost  of  living  in  check!  Buying 
only  needed  plentiful  goods  and  saving  the 
money  which  would  bid  up  prices  of  scarce 
goods  keeps  your  cost  of  living  from  rising. 
Save  automatically-—  regularly. 


Savings  chart.  Plan  above  shows  how  even 
modest  weekly  savings  can  grow  into  big 
figures.  Moral:  Join  your  Payroll  Savings 
Plan  next  payday. 


SAV£  THE  MM  WAY... 

st/y  YOUR  BOWS 

JHROVW  PAYROLL  SAVINGS 


Contributed  by  this  magazine  in  co-operation 
with  the  Magazine  Publishers  of  America  as  a  public  service. 


OCTOBER  1946 


I'LASTMCS 


65 


A  "B-17"  which  flew  into  northern  storm  areas  to  put 
polyethylene  to  the  acid  test  of  extremely  bad  weather 


parts  of  forthcoming  airplanes,  and  also  to  the  antenna  parts 
which  pass  through  the  fuselage  and  part-way  inside  the 
plane,  thus  insuring  that  the  electric  discharge  on  the  outer 
exposed  parts  of  the  airplane  can  not  touch  or  affect  any 
function  of  the  radio. 

The  research  which  resulted  in  the  recent  proposal  of  the 
remedial  plastics  application  began  in  1929.  At  that  time, 
the  Navy's  dirigible  USS  Los  Angeles  acted  as  a  laboratory 
for  operational  testing  of  an  electric  field  meter,  an  in>tru 
ment  which  measured  the  voltage  of  electrical  fields  around 
airborne  objects. 

Investigation  revealed  that  vertical  convective  current* 
are  generally  found  in  areas  where  aerial  electrical  phe- 
nomena existed,  and  the  field  meter  was  tested  for  its  ability 
to  measure  electric  fields  accurately  enough  to  warn  lighter- 
than-air  crews  of  the  imminence  of  up-  and  down-drafts 
which  might  strike  the  dirigible  and  cause  extreme  damage. 

Later,  this  instrument  graduated  to  work  in  the  field  of 
precipitation  static,  a  field  in  which  its  perfector,  Dr.  Ross 
Gunn,  head  physicist  at  the  Naval  Research  Laboratory, 
became  interested  during  the  thirties 


Dr.  Gunn  and  his  fellow  workers  found  that  rain-  and 
snow-static  is  separate  from  static  provoked  by  lightning, 
in  sound  effect  as  well  as  in  origin.  Putting  it  technically,  a 
nearby  atmospheric  electric  field  resulting  from  charged 
clouds  or  particles  in  the  air  striking  the  aircraft  oau>e> 
static  electricity  to  build  up  on  the  plane's  surface  in  exiv~-, 
of  the  dielectric  strength  of  the  adjacent  air. 

When  this  occurs,  the  accumulation  of  electricity  dis- 
charges into  the  surrounding  air.  The  effect  of  the  nearby 
discharge  of  excess  current  results  in  malfunction  of  radio 
sets  and  precipitation  static  occurs. 

"St.  Elmo's  Fire,"  a  flame  appearing  along  the  lines  of 
discharge,  is  at  the  extremities  having  the  smallest  radii 
of  curvature  such  as  trailing  edge  of  wings  and  empennage, 
pilot  tubes,  propeller  tips,  and  antennae. 

The  "fire"  never  actually  touches  the  plane.  It's  just  off 
the  aircraft  and  does  no  physical  harm.  The  real  danger  of 
the  discharge  of  excess  electricity  lies  in  the  blocking  out  of 
radio  transmissions  by  the  directly  resulting  precipitation 
static.  Intensity  of  the  disturbance  varies  proportionally 
with  the  speed  of  the  plane  and  the  amount  of  precipitation 
or  area  of  electric  field  incurred. 

In  a  clear  atmosphere  small  static  charges  accumulated 
by  an  aircraft  are  negligible.  In  an  area  of  precipitation, 
however,  three  conditions  may  produce  an  accumulation  of 
electricity  enough  to  warrant  corrective  action :  one,  fric- 
tion caused  by  striking  pellets  of  rain  or  snow;  second, 
striking  particles  divided  into  charged  fragments  upon  im- 
pact with  the  plane's  surface;  and,  last,  drafts  in  the  electric 
field  associated  with  thunderstorm*.  It  was  the  problem 
provoked  by  these  three  conditions  which  Dr.  ( iiinn 
attacked. 

Worst  static  being  on  long  flights  to  northern  areas  where 
precipitation  is  heaviest  the  year  round,  experimental  work 
was  centered  on  Northwest  Airlines'  route  between  Minne- 
apolis and  Fairbanks,  Alaska,  with  a  laboratory  at  Naval 
Air  Station.  Minneapolis.  There  the  Merlin-like  scientists, 
acting  under  government  controlled  secrecy,  set  up  a  giant 
generator  in  a  hangar  and  daily  shot  a  1,200,000  volt  cur- 
rent across  twenty  feet  of  space  to  a  suspended  multi- 
engined aircraft.  Results  were  precipitation  static. 

Having  successfully  simulated  precipitation  static,  the 
scientists  began  searching  for  a  preventive.  A  covering 


66 


In  naval  air  station  hangar,  a   1.200.000  Tolt  generator    (background)  simulated  precipitation  static  lor  test  purpose* 

PLASTICS  OCTOBER  1946 


Test  installation  of  polyethylene-covered  antennae  wire  on 
a  United  Air  Lines  "Mainliner  230"  shows  good  insulation 

for  the  antenna  that  would  successfully  prevent  any  elec- 
trical disturbance  from  entering  inside  and  travelling  the 
course  of  the  antenna  into  the  radio  set  was  needed. 

After  a  long  process  of  elimination,  polyethylene  was 
chosen  for  the  covering.  Tests  and  practice  have  shown 
that  the  material  will  afford  clear  reception  for  communi- 
cations equipment  if  it  remains  intact  and  without  puncture. 

The  "Sacred  Cow,"  President  Truman's  personal  plane, 
is  equipped  with  the  plastics,  and  Lt.  Col.  Henry  T.  Meyers, 
the  pilot,  reports  that  on  a  recent  trip  across  the  North 
Atlantic  when  bad  weather  caused  all  other  flights  to  detour 
south,  the  plane  went  through  without  trouble.  Snow  or 
some  other  form  of  precipitation  was  encountered  on  80% 
of  the  trip.  Though  on  several  occasions  the  corona  dis- 
charge completely  covered  the  windshield  and  sparks  were 
visible  on  other  parts  of  the  aircraft,  there  was  never  the 
slightest  interference  with  radio  reception  on  any  frequency. 

Though  the  President's  plane  is  one  of  the  first  to  put  the 
plastics  to  actual  use,  polyethylene  has  been  used  for  testing 
purposes  on  a  number  of  aircraft  for  some  time  at  Minne- 
apolis. A  B-25,  a  PV ,  and  a  B-17  have  all  been  used  in 
the  hangar  and  flight-tested.  A  small  twin-engined  Beech- 
craft  plane  is  now  being  flown  around  the  country  introduc- 
ing the  new  discovery  by  showing  it  in  practice. 

The  Beechcraft  is  equipped  with  an  automatic  charger 
capable  of  exerting  a  positive  or  negative  charge  of  350,000 
volts.  It  is  also  equipped  with  a  mechanism  which  changes 
the  antenna  for  the  radio  from  regular  to  polyethylene- 
covered  as  desired. 

Interested  investigators  may  listen  over  one  of  a  set  of 
six  earphones  within  the  plane  and  thus  ascertain  for  them- 
selves the  great  value  of  the  plastics  coating. 

The  application  of  polyethylene  to  prevent  electrical  dis- 
turbances from  causing  poor  reception  in  radios  is  not 
limited  to  aviation  set-ups. 

The  polarized  ethylene  is  merely  an  impregnable  sub- 
stance so  far  as  static  disorders  are  concerned.  It  allows  the 
metal  enclosed  antenna  to  pick  up  electrical  sound  waves 
in  a  normal  fashion  and  still  place  a  restraint  on  the  re- 
percussion of  electrical  discharges  nearby.  This  results  be- 
cause the  plastics  is  treated  to  be  non-conductive.  Covering 
the  antenna  so  that  there  is  no  contact  point  for  the  elec- 
trical discharge  precludes  the  possible  reception  trouble. 

The  original  ethylene  material  is  treated  in  the  usual 
polarizing  manner.  It  is  in  a  pliable  form  when  placed  on 
the  antenna.  Aircraft  are  to  be  equipped  with  three-six- 
teenths inch  coats  on  all  antenna  parts. 

Polyethylene  is  transported  to  aircraft  factories  in  hard- 
ened bulk  form,  but  a  heat  treatment  restores  its  pliability. 

At  the  present  time  the  Federal  Telephone  and  Telegraph 
Co.  of  New  Jersey  has  the  contract  for  all  government  use 
of  the  material.  Potential  greater  range  for  the  usage  of 
the  material  will  bring  about  more  agents  probably  in  the 
next  few  months.  END 


—  a  sure  cure 
for  that 

Plastic  Molding 
Headache 


TRADE   MARK 


The  principals  of  Kuhn  &  Jacob,  being 
experienced  tool  makers  themselves,  are 
well  qualified  to  help  you  solve  your  mold- 
ing problem. 

They  are  experts  in  their  line,  who 
learned  plastic  molding  in  the  early  days. 
The  experience  they  accumulated  is  back 
of  every  order  produced  by  this  firm. 

K  &  J  is  a  controlled  molding  service,  be- 
cause designing,  mold  making  and  mold- 
ing are  all  done  in  the  same  plant.  Put  that 
unusual  molding  problem  up  to  K  &  J. 

KUHN  &  JACOB 

MOLDI  NG&TOOLCO. 

1200   SOUTHARD   STREET,   TRENTON,  N.  J. 

CONTACT  TELEPHONE-TRENTON  S391 


THE  K  &  J 
REPRESENTATIVE 
NEAREST  YOU 


S.  C.  ULLMAN,  S5  W.  42NO  ST.,  NEW  YORK.  N.  Y. 
TELEPHDNE-PENN  3-0346 


T.  WYLER.  BOX  126,  STRATFORD,  CONN. 
TELEPHONE  -  STRATFORD  6-4496 


OCTOBER  1946 


PLASTICS 


67 


TAPS  ALL 
PLASTICS 

Cuts  deep,  smooth, 
Clean  threads  with- 
out chipping  holes. 


HOLTXTE 


Burnished 
vith  Slotted 
>rHOLTITE- 
hillips  Recessed 

Heads. ..All  Styles 


SCREW 


Pilot  point  ir. 
serted  in  hole 
aligns  screw 
for  straight 
driving 


A  practical,  production-proved  hardened  screw  that 
actually  fops  its  own  perfect  mating  threadt  in  any  ma- 
terial! In  plaitici  it  cuts  deep,  smooth  threads  without  chip- 
ping material  around  edges  of  hole,  or  bulging  hole  per- 
imeter upwards  in  laminated  plastics  with  paper  or  clolh 
fillers.  Length  of  thread  that  can  be  tapped  by  this  remark- 
able screw  is  many  limes  greater  than  its  own  diameter. 
Open  slot  ship  reservoir  readily  free*  tough,  gummy,  non- 
metallic  curlings  to  prevent  binding  and  reduce  driving 
torque  and  effort.  Send  for  samples  and  descriptive  folder. 


CONTINENTAL 

SCREW  COMPANY 

New  Bedford.  Massachusetts.U.S. A 


Originally   developed   in  the   form  of   label   holders   for 
packaging  machinery,  "Clastic"  has  many  potentialities 


Laminated 
Label-Holders 
are  Versatile 


AM().\(i  the  new  applications  for  plastics  which  not 
only  are  of  interest  and  significance  in  themselves  hut 
also  for  the  potentialities  which  they  suggest,  is  the  use  of  a 
F«'frer<;/<w-reinforced  Laminae  resin  laminate  in  the  manu- 
facture of  label  holders  for  packaging  machinery.  Known 
as  Clastic,  the  laminate  is  a  product  of  Laminated  Plastic-. 
Inc.,  Cleveland,  Ohio,  who  developed  the  holders  for  the 
N'ew  Jersey  Machine  Co. 

Because  the  new  laminate  can  be  laid  up  and  formed  in 
inexpensive  molds  at  very  low  pressures,  it  fulfilled  the 
first  major  qualifications  demanded  for  this  application, 
namely  economical  production  on  short  runs.  It  also  met 
the  requirments  of  strength,  wtarability,  and  appearance. 

Clastic  has  also  been  used  in  making  racks  for  holding 
automotive  bearings  during  electroplating,  and  fixture 
holding  irregular  shapes  for  drilling,  sanding,  or  buffing. 

Potential  applications,  according  to  Roger  B.  Whit* 
Laminated    Plastics,   include  contoured  parts  where  hand- 
worked iiu-tal  is  very  expensive  and  where,  though  now  used, 
wood   (  machined  or  hand-worked  to  shape)   fails  to  resist 
wear  satisfactorily  or  to  maintain  the  required  degree  of 
dimensional  -.lability.     Kxamples  of  Mich  uses  arc  guides  or 
runways  ancl  siipimrts  for  feeding  or  holding  all  sorts  of 
I>:irts   during  processing,  especially   where  the   guides  or  ' 
runways  must  be  handled  often  in  the  changing  of  setups  or 
must  remain  dimensionally  -t.il>]<-. 

White  believes  also  that  foundry  patterns  can  be  made 
lighter,  tougher,  and  probably  cheaper  than  from  metal 
becauM-  the  new  laminate  is  so  light  and  tough  and  can  lie 
molded  to  ^hape  over  a  wood  model  without  machining. 

Among  IIM--  currently  in  the  development  stage.  I-ami- 
uated  ri.i~ti.-~  lists  the  following:  (  1  i  short  run  contoured 


(is 


PLASTICS 


(HTOHKK   1916 


parts  where  expensive  dies  would  be  required  to  produce 
drawn  sheet  metal  parts;  (2)  contoured  parts  which  would 
otherwise  be  produced  as  thin  wall  aluminum  and  magne- 
sium castings  especially  where  the  wall  thickness  specified 
is  more  than  needed  simply  because  of  casting  requirements ; 
(3)  electrical  applications  where  a  combination  of  physical 
strength  and  insulating  properties  are  needed  beyond  those 
obtainable  with  conventional  materials;  and  (4)  chemical 
applications  where  suitable  metal  or  rubber  parts  would 
be  too  expensive  or  short  lived  or  both.  END 

Auto  Body  in  Plastics 

(Continued  from  page  50) 


by  dyes  or  pigments.  Either  procedure  would  eliminate  lac- 
quering and  would  provide  a  body  of  lasting  color. 

In  the  prototype  the  doors  are  of  steel,  merely  because 
these  were  fabricated  before  it  was  determined  to  utilize  a 
plastics  body.  For  further  prototype  or  mass  production, 
the  plan  is  to  employ  plastics  doors,  fabricated  like  the  body 
sections,  with  hinges  and  locks  installed  after  the  method 
for  mounting  the  hinge  bars. 

If  the  car  goes  into  mass  production,  Goldsworthy  says 
a  press  operation,  using  male  and  female  dies,  will  speed 
fabrication  of  either  body  section  to  6  min. 

To  provide  a  highly  scratch  resistant  body,  his  plan  is  to 
laminate  a  tough  outer  layer  of  thermosetting  material,  or 
possibly  a  vinyl  thermoplastic,  in  the  color  desired.  This 
not  only  would  eliminate  lacquering,  but  would  give  a  sur- 
face from  which  dust,  grit  and  grease  could  be  removed 
with  a  cleaning  rag  and  detergents,  and  which  would  take 
a  high  polish.  The  veneer  would  be  matched  to  the  color  of 
the  underlying  material. 


However,  there  are  problems  yet  to  be  overcome.  '1  he 
body  must  be  proved  with  use,  and  the  public  must  be  edu- 
cated to  this  plastics  application.  Tooling  would  have  to  be 
revolutionized,  with  the  old  tooling  for  metal  parts  scrapped 
in  favor  of  the  plastics  development. 

The  prevailing  shortage  in  dyes  and  pigments  must  be 
relieved;  or  should  a  water  clear  plastics  material  continue 
to  be  used  for  the  lamination,  a  special  primer  and  lacquer, 
which  is  suited  to  a  plastics  surface,  will  then  have  to  be 
developed. 

It  is  conceded  that  the  plastics  body  has  played  a  princi- 
pal role  in  reducing  the  weight  of  the  car.  The  overall 
prototype  machine  weighs  2400  Ib  as  compared  with  3000- 
3500  Ib  for  other  cars  of  like  dimensions  and  power.  If  the 
vehicle  gets  into  mass  production,  Darrin  declares  that  it 
can  sell  in  the  $2000  bracket.  END 


Mechanical  Testing 

(Continued  from  page  57) 


<> mimmni e 


load  of  Sl/2  Ib  applied  at  the  center,  distorts  or  sags  .010".  An 
oil  bath  supplies  the  heat  at  such  a  rate  that  the  specimen 
temperature  increases  1°  C  every  two  minutes. 

1  hermoplastics  have  a  "low  heat  distortion"  character- 
istic (100° — 180°  F)  whereas  thermosetting  materials  have 
a  "high  heat  distortion"  characteristic  (not  under  325°  F). 
This  is  why  thermoplastics  are  much  more  limited  in  their 
applications  than  thermosetting  plastics,  many  of  which  are 
continuously  used  in  temperatures  up  to  275°  F. 

Even  at  room  temperature  some  plastics  flow  or  creep 
considerably  under  steady  pressures.  This  is  commonly 
known  as  "cold  flow."  Where  a  plastics  is  supported  by 
rivets  or  bolts,  a  steady  pressure  is  exerted  on  it  under  the 


DESIGNED  FOR  EXPERIMENTAL  AND  PRODUCT  EXTRUDING 

Rugged  is  the  word  to  describe  this 
compact  and  highly  efficient  Royle 
continuous  extruding  machine.  It  em- 
braces all  of  the  characteristics  re- 
quired for  larger  and  heavier  extrusion 
processes. 

Primarily  designed  to  become  an  in- 
tegral part  of  laboratory  equipment — 
the  technician  can  be  sure  that  his 
experiments  will  parallel  actual  product 
extruding — the  Royle  #\  is  an  efficient 
producer  of  such  commercial  products 
as  tubes,  rods,  fine  wire  insulation, 
mono-filament  and  thread  coating. 

JOHN     ROYLE     &     SONS 

Pioneered   the   Continuous    Extrusion    Process    in    1880 

PATERSON  3,  NEW  JERSEY 

Lot  Angeles.  Cat. 

H.M.  Royal,  Inc. 

L*f*y>ttt2l6l 


James  Day  (Ma- 
chinery) Ltd. 

London,  England 
REgent  2430 


Home  Office 

B.  H.  Davis 

J.  W.  Van  Riper 

SHerwood  2-8262 


Akron,  Ohio 
J.   C.  Clinelelter 
University  3726 


OCTOBER  1946 


PLASTMCS 


69 


Tensile  and  Impact  Strengths  of  Some  Plastics  Materials 

(Average  Values) 

Edgewise 
Teniilj  Strength  Impact  Strength 

(psi)  (H-lb-in.  of  notch  liod) 


Phenolic  laminate  (Grade  XX). . 
Phenolic  laminate  (Grade  C). . . 

Vulcanized  fiber 

Melamine  "Fibergloi"  laminate . 
Hard  rubber 


.    9.000 0.5 

.10.000 3.5 

.10,000 5.0 

.33,000 10.0 

.    4,000 0.5 

Polyttyrene 7,000 0.4 

Methyl  methocrylate 7,000 0.4 

Nylon 10,000 0.9 

lignin  laminate 1 0,000 0.7 

Ca»ein 10,000 1.0 

Phenolic  molding  (no  filler) 8,000 0.4 

Resin  fibres 1  5,000 1.3 

Urea  formaldehyde 12,000 0.3 


heads  of  the  irts  and  bolts.  This  steady  pressure  causes 
flow  in  son  plastics  to  be  so  appreciable  that  in  a  rela- 
tively -hi if  time  the  part,  as  well  as  the  parts  it  supports, 
becomes  l<>"sc.  At  elevated  temperatures  this  creep  or  cold 
flow  is.  nf  course,  amplified. 

Cold  tlnw  is  measured  by  subjecting  a  Yi"  high  pile-up 
of  preconditioned  specimens,  cut  l/i"  by  y2"  sq,  between 
parallel  anvils  1"  by  1"  ^\  of  a  testing  machine,  under  a 
constant  load,  and  noting  the  flow  or  deformation  in  24  hr. 
The  testing  machine  is  placed  in  an  air-conditioned  room  to 
eliminate  the  effects  tit"  moisture  and  temperature  variations. 

It  is  interesting  to  note  that  plastics  which  have  a  "high 
heat  distortion"  characteristic  also  have  a  high  resistance 
to  "cold  flow,"  while  "low  heat  distortion"  plastics  have 
little  resistance  to  "cold  flow"  or  creep.  This  means  that 


only    the   thermosetting   plastics   are   used    in   applu 
where   Itmsi-ning   til"   the   riveted    part   cannot   lie   tolerated. 

The  moisture  absorbed  from  the  air  materially  affects 
the  mechanical  (and  electrical)  properties  of  some  plastics. 
Naturally,  then,  a  thorough  knowledge  of  tlu  ••:-, 

pickup  til"  tile  plastics  should  be  known  before  it  is  finally 
selected  for  a  specific  application.  To  make  a  rapid,  simple 
and  reproducible  test  of  how  much  moisture  a  material  \\ill 
absorb  from  humid  air  when  in  use.  a  sample  is  weighs 
on  a  sensitive  balance,  then  immersed  in  water  for  a  dew 
nite  immersion  time.  The  weight  of  absorbed  water  is  noted 
and  expressed  as  a  percentage  of  its  original  weight.  This 
value  is  known  as  its  water  absorption.  The  amount  of  wa* 
ter  and  hence  moisture  that  is  absorbed  depends  upon  the 
shape  and  size  of  the  specimen.  This  is  especially  so  in  the 
case  of  laminated  plastics  because  the  rate  of  absorpti"ii  is 
very  different  through  its  edges  than  through  its  natural 
surfaces.  The  AS  I'M  Standard  Method  for  water  absorp- 
tion definitely  specifies  the  specimen  shape  and  dimensions 
for  all  types  of  plastics  and  in  the  three  laminate  form: — 
sheet,  tube  and  rod. 

The  water  absorption  test  is  a  criterion  of  cure  and  is 
used  to  determine  proper  cure  of  many  thermosetting 
rials,  both  laminates  and  molding  powders,  especially  the 
ureas.     It   is   further  an  excellent   indication  of  the  extent 
to  which  the  material  will  change  its  electrical  pro) 
w  hen  exposed  to  humid  air. 

These  fundamental  tests  for  determining  the  mechanical 
strength  and  other  properties  of  plastics  materials  are  not 
difficult  or  time  consuming.  They  serve  the  designer  with 
sufficient  information  to  select  the  proper  plastics  for  hi» 
application,  whether  it  be  subjected  to  flexing,  pullit 
shock  li Kills.  MI 


\MI.IM: 
.m:imu; 

RESIN 


THI  KMOI'I   Wl  1C 

MOI  mv; 


CIBANITE 

\ 

SI'KCI  M.I  /I    I)   I' I    \STIC 

I OM     1  MH  STKI  \l       \  M) 

ELECTRICAL    USES 


HIGH  DIELECTRIC  VALUE 
HIGH  TENSILE  STRENGTH  -  LOW  LOSS  FACTOR 

LOW  WATER  ABSORPTION 

EXCEPTIONAL  ELECTRIC  STABILITY 

GOOD  MACHINING  PROPERTIES 

Literature  available  on  request 


<:IB\  PKOIH  CIS  COUr..  77  Kix-r  St..  1 1,, I.., km.  V  J. 


70 


OCTOKKK   H 


I 


Fabricating  Acrylic  Compacts 

(Continued  from  page  44) 


feed  is  automatic,  and  stops  are  provided  so  that  each  facet 
will  be  of  predetermined  area  and  depth.  A  hopper  beneath 
the  milling  cutters  catches  all  chips  and  feeds  them  into  the 
blower  system. 

The  third  production  step  includes  several  grinding  opera- 
tions to  form  and  bevel  the  hinge  block,  and  to  grind  a 
space  in  the  compact  body  for  the  opening  thumb  release. 
In  grinding,  an  AA-46-J6-V-10  white  silicon  carbide  wheel 
of  medium  grit  size  is  used. 

A  two-spindle  drill  mounted  on  a  two-way  lathe  bed  is 
used  for  drilling  the  pin  hole  in  the  hinge  and  hinge  block. 
The  hole  is  first  drilled  from  one  side,  then  reamed  from  the 
other,  insuring  precision  alignment. 

During  initial  production,  each  plastics  component  used 
in  the  compact  was  hand-polished.  This  method  was  not 
only  time-consuming,  but,  despite  the  fineness  of  the  polish- 
ing compounds,  failed  to  yield  a  microscopically  smooth 
surface.  The  process  was  therefore  replaced  by  flame 
polishing.  An  oxy-acetylene  flame  is  run  swiftly  over  the 
surface  of  the  plastics,  fusing  it  to  an  ultra-smoothness  and 
high  reflectivity,  while  the  edges  remain  sharp  and  clean-cut. 
With  hand-polishing,  uniform  precision  of  all  edges  is  not 
aways  possible. 

A  solvent  type  of  cement  was  originally  used  in  gluing 
the  hinge  blocks  to  the  upper  half  of  the  compact.  This 
step  is  now  performed  by  means  of  a  welding  process  simi- 
lar to  that  described  in  the  article,  "Acrylics  Can  Be 
Welded"  (p/osWcs.  November  1944).  The  half  of  the 
compact  and  hinge  blocks  are  jigged  into  position,  and  an 
electrically  heated  plate  is  inserted  between  the  interfaces 
to  be  welded.  At  exactly  the  right  instant,  the  heated  plate 
is  withdrawn  and  the  softened  interfaces  brought  together. 
This  provides  a  welded  joint  superior  in  strength  to  that 
obtained  by  ordinary  cementing  processes. 

Prior  to  final  assembly,  those  compacts  which  are  to  be 
colored  are  dyed.  Here,  too,  a  departure  from  the  conven- 
tional method  is  employed.  Instead  of  the  usual  plastics 
dyeing  compounds,  Mr.  Bucklein  utilizes  one  which  is  used 
for  dyeing  woolen  fabric.  Dye  temperature  is  maintained 
at  180°  F.  Time  required  for  immersion  of  the  plastics  in 
the  dye  varies  with  the  color  desired,  some  shades  being 
transmitted  in  an  instantaneous  dip,  others  needing  up  to 
1  min. 

Color  penetration  is  slight,  but  this  has  been  found  to  be 
immaterial  when  optical-quality  acrylic  is  used,  because  of 
the  "light-piping"  qualities  of  this  plastics.  In  illustration 
of  this  point,  Mr.  Bucklein  shattered  a  large  chip  from  a 
half  compact  which  had  been  dyed.  The  eye  could  not 
detect  that  the  broken  surfaces  were  uncolored.  In  fact, 
he  admits  that  he  has  often  trimmed  compact  halves  after 
dyeing,  without  affecting  the  color  quality.  (See  "How 
To  Make  The  Most  Of  Acrylics"  plastics.  June  1945). 

The  appearance  of  the  finished  compact  is.  perhaps,  the 
best  argument  in  favor  of  precision  workmanship  and  high 
quality  materials.  Despite  the  direction  in  which  the  com- 
pact is  turned,  one  or  more  of  the  flame-polished  facets 
appears  to  be  blazing  with  light.  Throughout  the  body  of 
the  compact,  scintillating  pinpoints  of  light  twinkle  and  dis- 
appear, only  to  reappear  in  a  burst  of  brilliance  when  the 
compact  is  moved. 

Minor  refinements  also  add  to  the  value  of  the  product. 
A  ring  insert  surrounding  the  powder  compartment  fits 
snugly  into  the  compact  top  when  closed,  effectively  pre- 
venting powder  leakage.  When  exterior  mirrors  are  used, 
they,  as  well  as  all  of  the  interior  mirrors,  are  of  a  blue- 
surface  variety,  thus  reducing  unwanted  reflection.  END 


H  COMPLETE  PUB" 

M.  «W»  «*«»  *»  * 


TO  YOUR  SPECIFICATIONS 

For  over  forty  years  we  have  been  leaders  in  the  design 
and  manufacture  of  component  parts  for  leading 
Refrigerator,  Stove,  Furniture,  Appliance  and  Cabinet 
industries.  We  specialize  in  custom  molding  by  the 
injection,  compression  or  transfer  method  in  any  ther- 
mosetting  or  thermoplastic  material.  A  complete  ser- 
vice from  one  source  to  serve  your  needs  —  at  no 
extra  cost. 

RESEARCH  — 

Highly  experienc- 
ed research  engi- 
neers to  deter- 
mine the  material  best  suited 
for  your  needs  as  to  strength, 
utility  and  beauty. 


ENGINEERING— 
Here  is  where  the 
correct  tools,  pre- 
cision dies  and 
molds  are  developed  to  pro- 
duce the  best  job,  efficiently 
and  economkally. 


MOLDING    —   A 

complete  depart- 
ment equipped 
with  the  latest 
and  most  modern  presses  and 
molding  equipment  —  for 
Injection,  Compression  or 
Transfer  molding. 


DESIGN  —  A  thor- 
ough study  is  made 
as    to    the    utility, 
shape  and  color  of 
the  plastic  part  that  will  best 
harmonize  with  the  style  and 
design  of  your  product. 


TOOL  AND  MOLD 
MAKING    —   This 

department,  manned 
by     expert     crafts- 
makes     the    necessary 
tools  and   molds  to  produce 
the  finished  product. 


men, 


INSPECTION 
AND  SHIPPING 

Each  individual 
piece  is  carefully 
inspected  for  uniformity,  col- 
or and  finish.  All  parts  are 
carefully  wrapped  and  packed 
for  utmost  protection. 


//  you  are  planning  the  use  oj  plastic  parts  in  your 
products,  it  will  be  advantageous  for  you  to  investi- 
gate our  complete  service.  Write  or  phone  us  about 
your  needs. 


NATIONAL   LOCK 
COMPANY 

Plastics   Division 

ROCKFORD,    ILLINOIS 


OCTOBER  1946 


I'LASTtCS 


71 


Polydichlorostyrene  "DCS" 
A  JVew  Thermoplastic 


GKKATKk  n-M-tance  l<>  heat  than  any  other  thermo- 
pla^tic  has  and  outstanding  electrical  properties  are 
claimed  for  polydichlorostyrene  recently  developed  by  The 
Mathieson  Alkali  Works.  This  molding  powder  is  a  polymer 
of  dichlorostyrene,  a  modified  styrene,  which  combines  the 
good  features  of  styrene  together  with  excellent  heat  re- 
Mstance,  increased  hardness,  increased  resistance  to  cold 
flow,  and  greater  dimensional  stability.  It  differs  from  other 
chlorine  containing  plastics  materials  in  that  the  two  chlo- 
rine atoms  are  firmly  bound  to  the  benzene  ring  and  are  not 
released  until  mnlmstion  temperatures  are  reached.  Even 
after  ignition,  the  combustion  is  not  self-supporting,  and  the 
pla-tics  may  l>e  termed  self-extinguishing. 

Resistance  to  Heat 

Molflod  parts  of  DCS  can  be  boiled  indefinitely,  and 
normal  steam  sterilization  cycles  do  not  cause  softening  or 
distortion.  Tests  have  indicated  that  maximum  service  temp 
of  220°  F  are  possible  without  loss  of  dimensional  stability. 

Easily  molded  by  standard  commercial  injection  molding 
machines,  this  thermoplastic  molding  powder  requires  slight- 
ly higher  cylinder  temp  than  most  styrene  formulations. 
The .  recommended  range  is  420-500°  F,  using  medium  to 
high  molding  pressures. 

The  ASTM  (D648-41T)  Distortion  Under  Heat  Tempera- 
ture of  DCS  is  230-248°  F.  This  factor  combined  with  its 
low  water  absorption  and  unlimited  range  of  color  possibili- 
ties extends  the  economies  and  high  production  rates  of  in- 
jection molding  techniques  well  into  fields  of  application 
formerly  limited  to  thermosetting  materials. 

Mold  shrinkage  of  polydichlorostyrene  is  normally  in  the 
range  of  0.002  in/in,  so  that  it  lends  itself  to  parts  which 


complex  shapes  with  critical  dimensions  or  to 
with  intricate  inserts.    Small  inserts  are  rigidly  held,  and 
weld-line  failures  for  large  insert  pieces  are  minimized. 

Polydichlorostyrene  is  odorless  and  tasteless.  It  ha>  i-x- 
cellent  resistance  to  hydrochloric  acid,  nitric  acid,  sulfuric 
acid,  ammonium  hydroxide,  sodium  hydroxide  dilute  and 
concentrated  at  room  temp.  Gain  in  weight  was  less  than 
0.1%  when  immersed  in  sulfuric  acid  of  1.26  specific  gravity 
at  90°  C  for  48  hr.  It  is  unaffected  by  the  lower  alcohols, 
aliphatic  hydrocarbons,  glycols,  and  vegetable  oils.  It  is 
soluble  in  aromatic  hydrocarbons,  chlorinated  hydrocarbons, 
some  esters,  some  ethers,  and  some  ketones. 

In  mechanical  and  electrical  properties  it  resembles  sty- 
rene except  that  it  has  greater  hardness.  Its  dielectric  con- 
stant and  power  factor  are  practically  constant  over  a  range 
of  frequencies  from  1  X  102  to  3  X  10s  cycles. 

Color  Possibilities 

Transparent  and  colorless,  DCS  may  be  colored  to  any 
desired  shade  by  the  addition  of  dyes  and  pigments.  It  is 
available  at  present  only  in  the  natural  clear  powder. 

Among  the  many  uses  for  which  the  new  molding  po\\<l<-r 
is  expected  to  find  application  are  in  many  household  articles 
such  as  strainers,  funnels,  handles,  stoppers,  plumbing  fix- 
tures ;  industrial  equipment  where  chemical  and  hot  water 
resistance  are  of  importance;  electrical  parts;  and  surgical 
and  medical  appliances. 

Currently,  DCS  is  to  be  had  only  in  semi-commercial 
quantities.  ^  \n 


This  article  is  based  on  a  paper  presented  by  L.  E.  Russell  of  The  M.ithir 
son  Alkali  Works,  Inc.,  at  a  meeting  of  the  Chicago  Section  of  thr 
of  Plastics  Engineers,  Inc.,  on  Sept.  3. 


PROPERTIES  OF   POLYDICHLOROSTYRENE  "DCS- 


GENERAL 

Specific  gravity 1.39 — 1 .40 

Specific  volume,  ex.  in./lb 1 9.8 — 1 9.9 

MECHANICAL 

Tentile  strength,  psi 6,500 — 8,500 

Compretsive  strength,  psi 1  3,000—20,000 

Flexural  strength,  psi 7,500 — 1  5,000 

Impact  itrength,  ft.  Ib./in.  notch 

(  Vi  »   '/i  bar  liod  test,  machined  notch) 0.30—0.60 

Rockwell  hardness. . .  M90 — M100 


ELECTRICAL 

Dielectric  strength,  volts  per  mil  (short  time) 370 

Dielectric  constant,  60  cycles 2.64 — 2.66 

Dielectric  constant,  1 0'  cycles 2.64 — 2.66 

Dielectric  constant,  10*  cycles 2.64 — 2.66 

Power  factor,  60  cycles 0.0003—8 

Power  factor,  10"  cycles 0.0003 — 8 

Power  factor,  I0«  cycles 0.0003—8 

OPTICAL 

Refractive  mde«,  N/0  25    C 1 .62—1 .64 

Clarity Transparent 

Color  possibilitiet Unlimited 


THERMAL 

Resistance  to  heat,    F  (continuous) 21  2 — 230 

Diitortion  under  heat,     F 230 — 250 

Burning  rate Self-extinguishing 


STABILITY 

Water  absorption,  '  ,   after  immersion 

24  hr.,  Vi  thickness 0.02 — 0.04 

Effect  of  sunlight Yellows  slightly 


FABRICATING  AND  MOLDING  DATA 

Molding  qualities Good 

Machining  qualities Good 

Effect  on  metal  Inserts Inert 

Compression  molding  temp..    F 325 — 400 

Compression  molding  pressure,  psi 1,000 — 5,000 

Compression  rotto 2.1—2.4 

Injection  molding  temp..    F 375 — 500 

Injection  molding  pressure,  psi 1 0,000—30,000 

Mold  shrinkage,  in./in.  (injection) 0.001—0.005 

EFFECT  OF  CHEMICALS 

Not  affected  by  weak  or  strong  acids    weak  or  strong  alkalis.  Soluble  In 
aromanV  and  chlorinated  solvents. 


PI.\STI<  * 


(MTOHKK  1'Mfi 


Compression  Mold  Design 

{Continued  from  page  43) 


i 


also  break  very  easily  under  the  pressure  required  to  eject 
some  castings.  Therefore,  the  pins  should  be  as  large  as 
is  consistent  with  the  design  of  the  piece.  Three-sixteenths 
or  one-quarter  of  an  inch  diameter  should  be  considered 
the  minimum  whenever  possible.  If  small  pins  are  the  only 
solution  they  should  be  reinforced,  as  shown  in  Fig.  9. 

The  ejector  pin  bars  should  always  be  equipped  with 
return  pins  (Fig.  6).  These  make  certain  that  the  knock- 
out pins  will  be  returned  to  their  normal  position  as  the 
mold  closes.  If  this  is  not  done,  there  is  danger  that  the 


L 


MOLDINGS 

PUNCH  HALF 
BOAKD  fLACCO 

£"""7*  Berive  CN  TO 

II 

n  u  u  u  u  u 

LII  n  n  ii  AI  • 

FROM  PUHCH 

CATCH  MOLDINGS 
CAVITY  HALF 

^^/yyy^y^ 

MOLD  OPCN 

Fig.  7.    Pieces  knocked  o«  punch  fall  free  of  top  mold  half 


n 


\ 


^VA 


^PICK-UP  60OOV£ 


\ 

KMOCK  OUT  PIN 


Fig.  8.    Pickup  grooves  make  casting  stick  for  top  ejection 


ALLOW  roe 

SUFFICIENT  fTffOfC 
TO  IJfCT  CASTIHS 


Fig.  9.    Construction  used  to  strengthen  weak  knockout  pins 


PLASTICS 


EEEEj 


WE    BOY 


Thermoplastic  Scrap- 
Rejected  Molded  Pieces 

__  Obsolete  Molding 
Powders-and  pay 
highest  prices 


WE   SEtt 


to  tit  Y°ur 


needs 


Your  scrap  ior 
WE  SPECIALIZE  in  cus- 
tom grinding,  magneto- 
ing.  separating  an« 

re-working- 


CELLULOSE  ACETATE    .    POLYSTYRENE    •    METHYL  METHACRYIATE 

A.BAMBERGER 

CORPORATION 

44     HEWES     STREET,     BROOKLYN     11,     N.     Y. 
PHONE:  EVERGREEN  7-3887  •  CABIE:  CHEMPROD  BROOKLYN 


CELLULOSE  ACETO  •  BUTYRATE 


POLYVINYL  RESINS,  ETC 


OCTOBER  1946 


PLASTICS 


73 


Fig.  10.     Mold  where  stripper  plate  accomplishes  ejection 

cavitir-  ur  ]iutiches  may  IK-  dented  by  the  pins  as  the  mold 
eloM  >.  thereby  causing  e.x|K'M>ive  die  repairs. 

(  >ii  many  compression  molds  ejection  is  better  accom- 
plisheil  by  a  stripper  plate  than  by  knockout  pins.  Such 
a  mold  is  shown  in  Fig.  1"-  On  small  jobs  the  stripper  plate 
is  hardened,  but  on  multicavity  molds  it  is  usually  left  soft, 
and  the  stripping  is  done  with  hardened  bushings  pressed 
in  the  plate  and  held  in  place  by  a  backing  plate.  The 


Fig.  11.     Bottom  half  of  compression  mold  showing  support 

stripper  plate  is  operated  by  pins  extending  down  from 
the  knockout  bars,  and  rides  on  guide  pins  which  are  a 
press  fit  in  the  pin  plate  and  a  slide  tit  in  the  stripper 
plate  and  cavity  plate.  The  stripper  is  equipped  with  straps 
to  stop  its  downward  motion  after  it  has  dropped  far 
enough  to  clear  the  pieces  from  the  punches.  This  stripper- 
plate  type  of  ejection  gives  a  good  running  mold;  elimi- 
nates warping,  broken  pins,  and  cracked  castings,  often 
encountered  in  the  use  of  knockout  pins;  and  therefore 
often  offsets  the  higher  die  cost  usually  encountered. 

Whether  the  mold  is  designed  for  knockout  pins  or  strip- 
per plate  ejection,  the  parallels  which  support  the  mold 
must  be  high  enough  to  allow  the  knockout  bar  to  come 
far  enough  forward  to  completely  clear  the  casting  from 
the  cavity  or  punch.  Also,  the  designer  must  remember 
that  molding, pressures  are  large  and  may  bend  the  die 
plates  if  this  knockout  area  is  not  supported  in  the  center 
by  additional  bars  (Fig.  11).  TO  BE  CONTINUED 


THE  CEE-BEE  MFG.  CO. 

PLASTIC   SLITTING,  CUTTING   &   SHEETING    PROBLEMS    SOLVED 


We  slit  all  types  of  plastic  materials  including  cellophane,  acetates,  etc., 

from  1/16  inch  to  75  inches  in  width. 
We  interleave  plastics. 

We  are  equipped  to  slit  up  to  100,000  yds.  per  day. 
Prompt  service. 
Storage  space  available — Equipped  with  railroad  siding. 


WE  ALSO  SHEET  PLASTIC  MATERIALS  FOR  PRESS 
.POLISHING  USED  IN  THE  LADIES  HANDBAG  4  SHOE 
TRADES  AND  FOR  ALL  OTHER  PURPOSES. 

Write  to  Us  About  Your  Plastics  Cutting.  Slitting  and  Sheeting  Problems 

T.I.  Iv.  7-1331 

76  N.  4th  ST.  BROOKLYN   11,  N.  Y. 


74 


f»l.  .t.STI  *  * 


0<  TOHKK    I1' It. 


(Attractive,   expensive   looking,   corde-type   handbags   can  be 
[produced  at  modest  cost  by  home  users  of  "Plasticraft"  thread 


Art  Needlework 
Goes  Modern 


y   ff^arb 


a ra    V-Jaer 


NEXT  time  you  see  gleaming  plastics  thread  follow  a 
steel  crochet  hook  out  of  a  sewing  bag,  don't  blink. 
Art  needlework,  distinguished  branch  of  traditional  handi- 
craft, is  going  modern.  For  Plasticraft,  spooled  extruded 
vinyl  resin  monofilament,  is  being  featured  on  most  of  the 
counters  of  the  country's  5,000  art  needlework  departments 
in  stores  and  shops,  and  needlecrafters  are  making  fashion- 
able corde  type  crocheted  handbags. 

Product  of  the  18-year-old  Paragon  Art  and  Linen  Co., 
Inc.,  the  new  material  for  crocheting  retails  at  $1  per  spool 
of  200  yards.  After  purchasing  lining  materials,  crochet 
hook,  and  the  Plasticraft,  cost  of  a  home-made  purse  re- 
main.s  under  $5,  although  the  equivalent,  sold  by  the  stores, 
would  cost  as  much  as  eight  times  that  price,  it  is  said. 

The  needlework  company  has  designed  several  styles  of 
bags,  models  of  which  are  made  available  to  retailers  at 
low  cost.  These  are  displayed  in  the  art  needlework  depart- 
ments together  with  the  instruction  books  and  sheets  issued 
by  Paragon  and  the  spools  of  Plasticraft  in  black,  brown, 
navy,  red  and  white. 

Because  Paragon  Corde  (40%  rayon,  60%  cotton)  had 
been  a  phenomenal  seller  for  handbags  and  hats,  the  com- 
pany experimented  with  plastics  extrusions  which  could  be 
worked  in  the  same  way,  but  which  would  offer  long-wear 
advantages.  Chief  problem  was  to  find  a  monofilament  plia- 
ble enough  to  be  worked  without  hurting  the  crocheter's 
hands.  Most  threads  were  found  to  be  too  wiry.  Another 
problem  was  to  find  a  thread  which  would  not  snarl  and 
knot  up  while  being  crocheted. 

Plasticraft  was  introduced  and  according  to  the  company 
"is  proving  a  spectacular  success."  It  is  expected  to  be 


Continental  Plastics  Corporation 


CONTINENTAL 

PLASTICS  CORPORATION 


308   WEST   ERIE   STREET 


CHICAGO   10,  ILL. 


OCTOBER  1946 


PLASTICS 


75 


GRAYS  HARBOR  OFFERS 
THESE  OPERATING  ADVANTAGES 

/  ABUNDANT  SUPPLY  OF  "PLASTIC  TYPE"  TIMBER 

/  SUPPLIES    OF   WASTE   MATERIAL    FROM    EXISTING 
MILLS 

</  HIGH  GRADE  INDUSTRIAL  WATER  SUPPLY 

I/  BONNEVILLE  ELECTRIC  POWER  FOR  INDUSTRIAL 
PURPOSES 

•  EXCELLENT  TRANSPORTATION  -  HIGHWAY,  RAIL, 
SEA  AND  AIR 

i/  SURPLUS  OF  EFFICIENT  LABOR 

* 

FOREST-BASED  PLASTIC  PRODUCTION  NEEDS 
THESE  ADVANTAGES  FOR  SUCCESSFUL  OPERATION 
-THEY  ARE  AVAILABLE  NOW  AT  GRAYS  HARBOR. 
DIRECTLY  TRIBUTARY  TO  ABERDEEN  AND  HO 
OUIAM  STANDS  A  HUGE  BACKLOG  OF  PLASTIC 
TYPE  TIMBER  AGGREGATING  SOME  TWELVE  BIL- 
LIONS OF  FEET.  ACCORDING  TO  U.  S.  FOREST  SER- 
VICE SURVEYS,  THIS  TIMBER  GROWS  FASTER  AND 
BIGGER  THAN  ANYWHERE  ELSE  IN  THE  UNITED 
STATES.  UNDER  SUSTAINED  YIELD  CUTTING,  IT 
WILL  PRODUCE  A  HUGE  CROP  OF  BASIC  MATERIAL 
FOR  WOOD  PLASTICS  FOR  ALL  TIME  TO  COME. 

YOUR  OPERATING  PROBLEMS  CAN  BE  ANSWERED 
AT  GRAYS  HARBOR.  WRITE  FOR  SPECIFIC  INFOR- 
MATION, OR,  IF  YOU  PREFER,  A  PERSONAL  REPRE- 
SENTATIVE WILL  CALL  ON  YOU 

i  Seattle 
•  Tocoma 


Hoquiam   ^     ^  Aberdeen 

GRAYS   HARBOR 


Portland 


GRHVS  HORROR 

HI        ° 

Spontored  by 
GRAYS   HARBOR   INDUSTRIES,  INC. 

ABERDEEN,  WASHINGTON 


mo-t  popular  for  spring  .-nul  -ummer  u-e  both  in  bag-  and 
hats. 

An  average  of  three  spools  is  required  to  make  a  hag. 

•r  chain  stitching,  slip  stitching  single,  double  and  treble  , 
crocheting  as  directed,  the  instruction-  tell  the  amateu 
maker  how  to  cut  buckram  and  lining  cloth,  sew  gussets^H 
achieve  shape,  and  finish  with  a  zipper,  crocheted  button 
and  loop,  or  plastics  clasp.    Most  needle  worker,  are  said  tfl 
be  able  to  make  a  bag  of  this  type  in  several  ,;. 

Hal  models  and  instruction  sheets  are  being  worked  on  I 
at   present  by   the  company'-   design   department.          •  \D 


Molded  Vinyls  Solve  Problems 

(  ( 'ontinufd  from  page  38) 


of  molding  comiNuindi  that  two  knobs  were  designed  to 
bring  up  the  weight  of  the  shot.  One  of  these  knobs,  as  in 
the  brake  pedal  cover  job,  is  used  to  strip  the  -hot  from 
the  press. 

I'ldin  it>  own  experience  in  molding  the  elastomeric  vinyl 
compounds,  Hungerford  has  established  the  nece-sity  of 
certain  precautions.  First  of  all,  it  is  important  to  t;uard 
against  the  breaking  off  of  the  sprue  in  the  sprue  bushing, 
for  it  is  difficult  to  get  it  out  if  it  does  break.  Positive 
ejection  overcomes  this  difficulty.  In  the  design  of  the  sprue 
bushing,  a  negative  draft  or  taper  is  created  which  cau-e- 
pressure  on  the  ejection  pin.  This  enables  it  to  lock  and  to 
be  pulled  out  as  required,  by  means  of  a  hook  sprue  puller. 
The  main  part  of  the  sprue  in  the  stationary  part  of  the 
mold  has  a  positive  taper. 

A  second  desideratum  is  to  overfeed  the  molding  com- 
pound, in  order  to  effect  a  good  finish  and  avoid  scuff  marks 
on  the.  molded  piece.  If  only  a  little  more  than  an  exactly 
weighed  shot  is  used,  the  finish  i-  likely  to  be  less  smooth, 
and  scuff  marks  may  show. 

Whether  a  filled  or  unfilled  compound  is  used,  it  is  im- 
portant to  watch  the  flash.  The  parting  line  should  be  in- 
tact, and  maximum  clamping  pressure  employed. 

When  light  color-  are  run,  it  is  desirable  to  have  a  lower 
back  temperature  in  the  cylinder — say,  _'7'i  1  .  a-  against  a 
nozzle  temperature  of  300°  F. 

Most  vinyls  are  formulated  with  a  lubricant  to  ease  their 
flow  through  the  heating  cylinder  and  to  effect  mold  release, 
so  that  there  i-  no  need,  generally  speaking,  for  an  external 
mold  relea-e. 

Thermal  breakdown  of  the  compound  in  the  die  must  be 
avoided  since  hydrochloric  acid  is  formed,  which  would 
react  with  the  steel.  A  stainless  steel  has  been  found  best 
a-  die  material  to  resist  such  chemical  action. 

It  wa-  noted  or  implied  in  several  of  the  examples  cited 
above  that  a  considerable  amount  of  the  charge  was  "lo-t" 
in  the  sprue-,  runner-  and  gate-.  This  material,  it  has  been 
fmmd.  can  be  re-run  by  itself  or  mixed  with  virgin  com- 
pound, with  gcxnl  re-ult-. 

Finally,  it  may  be  noted  that  when  a  pre—  ha-  Itecn  used 
for  molding  the  vinyl  compound-  and  a  run  i-  to  be  made 
with  acetate,  it  i-  necessary  to  purge  the  cylinders  with 
acetate  In-fore  going  into  production.  END 


7fi 


T*«  lor  tun  still,  produced  with  specially  mad*  die 
i*  I.. 1ST  H'S  OCTOBKR  1946 


WHAT'S 


I 


PLASTIC  S 


X-Ray  Photometer 

General  Electric  Company 

1  River  Rd.,  Schenectady  5,  N.  Y. 

A  new  instrument  which  is  said  to  be  nondestructive  to  most 
materials,  indicates  and  records  concentration  of  one  chemical 
element  in  the  presence  of  others  in  solids,  liquids  or  gases,  by 
measuring  the  change  in  absorption  of  X-rays  between  a  sample 
and  a  standard. 

This  X-ray  photometer  can  be  used  for  determining  hydro- 
carbon, chlorine  or  fluorine  content  of  plastics ;  sulphur  content 
of  oil ;  and  various  other  applications.  Sensitivity  of  this  method 
of  analysis  varies  from  0.01%  to  1%,  depending  upon  the  differ- 
ence in  atomic  numbers  of  the  components  making  up  the  speci- 
mens. 

A  standard  control  cabinet  72"  by  28"  by  20"  houses  the 
unit (587) 


operator  are  those  of  starting,  opening  and  loading  the  mold 
cavities (588) 


Hydraulic  Presses  for  Molding 

Pomona  Machine  Works 
Pomona,  Calif. 

Of  two  models  of  molding  presses  now  available  in  sizes  up 
to  300  tons,  the  first  has  a  downward  acting  ram,  with  the  pull- 
back  cylinder  and  ram  located  at  the  top  of  the  press.  The  second 
model  has  an  upward  acting  ram,  with  the  pull-back  cylinder 
located  either  at  the  bottom  or  at  the  top.  If  desired,  it  may  be 
provided  with  both. 

These  presses  are  semi-automatic  in  operation.  The  mold 
remains  in  the  press,  and  the  operating  cycle  may  be  established 
in  advance  of  the  actual  operation.  The  only  functions  of  the 


Miniature  Thermostat 

Mechanical  Industries  Production  Company 
235  Ash  St.,  Akron,  Ohio 

A  perfectly  sealed  thermostat  especially  designed  in  size  and 
shape  for  molding  in  rubber  and  various  plastics  materials,  the 
Mighty  Mite  is  built  to  withstand  the  toughest  kind  of  treatment 
without  changing  its  temp  setting;  is  pre-set  to  temp  specifica- 
tions; has  J/jj"  silver  contacts;  and  gives  extra  safety  and  heat 
control  accuracy. 

Exceptionally  small,  thin,  durable  and  lightweight,  this  ther- 


In  rapidly  moving  times  such  at  these,  keeping  up 
with  every  latest  development  in  one's  field  is  a 
"must."  In  order  to  simplify  for  our  readers  the  task 
of  obtaining  detailed  information  regarding  the  new 
products,  processes  and  trade  literature  described 
herein,  plastics  has  keyed  each  item  in  this  section 
with  a  number,  and  has  provided  the  name  and  ad- 
dress of  the  manufacturer  «r  producer  of  each. 

Mention  of  the  key  number,  and  of  the  issue  of 
plastics  in  which  the  news  item  appeared,  will  serve 
as  quick  identification  of  the  product  when  writing 
the  individual  manufacturer  or  producer  for  further 
details. 


(pLcuJticA.  ^hamdaiinq. 


Expressly  designed  for 
granulating  the  various 
types  of  plastic  materials 

Advanced  design  features  enable 
Cumberland  machines  to  perform  at 
maximum  efficiency  the  special  cut- 
ting required  by  plastics  materials. 
Machines  are  made  in  two  styles: 
smaller  machines.  No.  0,  No.  Vi  and 
No.  P/2  as  at  right  (No.  '/2  illus- 
trated). Style  of  large  machines  as  at 
left  with  retractable 
knife  block  for  maxi- 
mum accessibility  (18" 
Machine  illustrated). 

Request  illustrated 
CATALOG  NO.  200 

CUMBERLAND  ENGINEERING  CO. 

Dept.  B — Box  216,  Providence,  R.  I. 


OCTOBER  1946 


PLASTl CS 


Specify  MICCROPLATE  Super-Finish  ...  the  finest  of 

HARD  (HRomium 

PIBTIHC  FOR  PLRSTIC 
HIOIDS  RHD  DIES 


MICCROPLATE  Super-Firmh  it  a  new  improved  hard 
chromium  plating  technique  developed  by  specialist*  of 
the  Michigan  Chrome  and  Chemical  Company  ...  It 
produces  high-luster  castings  —  eliminates  repolishing, 
corrosion,  pitting  and  discoloration  —  prevents  material 
adhesion,  facilitates  material  flow,  reduces  wear  and 
preserves  mold  finish. 

Send  your  molds  and  dies  for  M/CCftOPLATf  Super- 
Fin^.  All  work  guaranteed.  24  HOUR  SERVICE! 


D»v*fop*d  ond  Manufatturvd  by 


MICHIGAN    CHROME    and 
CHEMICAL    COMPANY 

6342  East  Jefferson  Avenue 
Detroit  7,  Michigan 


AQUA        PLASTIC        DYE 


Patent  Pending 


H, 


Lere  is  a  Permanent  dye  in  Water 
solution!  Developed  especially  for  your  clear  plastics. 
AQUA  PLASTIC  DYE  has  these  outstanding  features: 
(a)  Ease  of  application —30  to  60  seconds  immersion  in  200°  F 
water  to  which  dye  has  been  added  (b)  color  deposits  evenly 
(c)  plastic  retains  polished  luster  (d)  fire  hazard  eliminated 
(e)  no  unpleasant  or  toxic  odors. 


GREAT  AMERICAN 
COLOR  CO. 

25)2   w.il    N.nth   Sir.. I, 
lot  Ang./.i  6.  California 

N.w  York  ».p  Pfoif.ci  Or*  4 
Suppfy  Co.,  Oc«on  Go'*,  Ntw 
J*r\*y  Chicago  Kmp:  Acm«  ffolhci 
SuppV  Co.,  133  Chicago  Ay.  . 
fvonifon,  llltno't 

Alto  monvrocfurinp  o 
compf.r.  fin*  ol  told  dip  df.i 


AQUA  PLASTIC  DYES  in  IS  boiic 
colort  for  any  of  150  lowly  po«f*l 
Of  brilliant  snad.i  in  a  mott*r  of 
i.cond»  Highly  r*comm*nd*d  for 
m*lhocrylot*»,  nitrotvft.  oc«lot«t. 
oc.tobuty  rat»»,  .lhy  I  c.llulot.  and 
vinyl  chloride. 

Olh.r  CHEAT  AMERICAN  prod 
uclt  includ«  mGAMCCC,  o  Sion- 
burning"  buffing  compound  for 
ploilici:  ANNEALING  COM- 
POUND which  cr.oi.i  a  bond 
ttrongvr  than  th.  ploitic  ill. If 
LAMINATING  COLORS,  a  c.m.nl 
with  color  —  no  air  bubbUt.  no 
tlr.oki 


mostat  has  wide  applications  in  the  electrical  field.  It  is  tamper-, 
dust-  and  water-proof.  Having  a  fibreglass  insulation,  it  is  im- 
pervious to  effects  of  humidity  or  freezing  weather.  Its  sealed 
tubular  construction  withstands  great  external  pressure,  will 
neither  bend  nor  break. 

Standard  model  is  pre-set  for  fixed  temp  up  to  300°.    Other 
models  are  available  for  settings  up  to  600° (589) 


Flat  Lapping  Machine 

Spitfire  Tools.  Inc. 

2933  N.  Pulaski  Rd.,  Chicago  41,  111. 

Among  the  many  uses  of  the  new  Spitfire  Precision  Flat  Lap- 
ping Machine  are  precision  flat  lapping  of  machine  and  tool  parts, 
flat  sliding  surfaces,  flat  rotating  surfaces,  air-tight  and  liquid- 
tight  seals,  and  flat  surfaces  on  plastics  molds,  die-casting  molds 
and  drawing  dies. 

It  is  possible  to  obtain  a  surface  finish  as  fine  as  2  rms  micro- 
inches.  On  single  pieces,  the  product  is  laid  on  the  revolving 
circular  lapping  plate  and  the  operator  directs  its  motion  man- 
ually. Production  lapping  is  done  rapidly  by  using  standard  or 
special  holders  to  suit  particular  requirements. 

Kxtra  standard  or  special  lapping  plates  for  various  uses  are 
available  which  are  easily  put  on  and  taken  off  the  machine  with- 
out tools  of  any  kind,  as  no  fasteners  are  necessary  to  hold  the 
plate  on  the  machine (590) 


Small  Sixe  Mixer 

Parrel-Birmingham  Co.,  Inc. 
25  Main  St.,  Ansonia,  Conn. 

A  new  small  size  mixer,  the  1A,  has  been  added  to  this  com- 
pany's line  of  production  units  for  the  plastics  and  rubber 
industries. 

Steel  mixing  rotors  are  cored  for  circulation  of  temperature- 
regulating  medium,  coated  with  abrasion-resistant  metal  on  their 
peripheries,  and  fitted  with  end-thrust  adjustment.  Sides  of 
mixing  chamber  can  be  either  the  spray-cooled  type,  or  cored 
type  arranged  for  either  heating  or  cooling.  Find  frames  are  of 
heavy  castings  fitted  with  bronze  bushings  for  the  main  bearings 
which  are  provided  with  pressure  grease  lubrication. 

A  potentiometer  pyrometer,  which  has  a  thermocouple  in  direct 
contact  with  the  batch  to  provide  accurate  temp  readings 
throughout  entire  mixing  cycle,  provides  accurate  control  of 
temp  during  mixing  operation.  A  telechron-operated  timing  de- 
vice flash-signals  the  operator  each  time  an  ingredient  is  to  be 
added  to  the  batch,  thus  assuring  uniformity  in  successive 
batches (591) 


Abrasive  Items 

Detroit  Mold  Engineering  Co. 

6686  E.  McNichols  Rd.,  Detroit  12.  Mich. 

Three  additions  to  its  line  of  abrasives  has  been  announced 
by  this  company  as  being  available  for  immediate  delivery.  The 
first  is  an  abrasive  powder  packaged  in  contamination-proof 
containers.  This  abrasive  is  rapid-cutting  used  dry  or  with 
kerosene  and  imparts  a  high  luster. 

The  second  item  is  a  mold  polishing  compound  which  is  a 
ilispcrsion  of  silicon  carbide  abrasive  in  an  oil  carrier. 

A  stock  of  coated  abrasives  in  a  size  specifically  made  for 
bench  use  in  a  mold  shop  is  the  third  product.  The  cloth  is  put 
up  in  50-yd  rolls  2"  wide.  This  abrasive  cloth  is  said  to  be 
unique  for  its  long  life  and  heat  resistance,  qualities  obtained  by 
coating  each  abrasive  grain  with  a  layer  of  resin (592) 


SPEED  PRODUCTION. LOWER  DYEING  COSTS 


Two-Spindle  Borer 

Moak  Machine  and  Tool  Company 
Port  Huron,  Michigan 

A  completely  enclosed  Silrcr  Top  which  permit-  movement  of 
the  head  to  any  |H,Mtion  in  a  90°  arc  and  adjustment  of  the 
spindles  from  1-1/16"  to  12"  apart,  is  an  important  feature  of 
the  two-spindle  radial  borer  which  ha*  recently  IH-OII  designed  to 
meet  the  demands  of  the  plastics,  furniture,  light  metal  and  allied 
Industries. 

Right  hand  spindle  i-  stationary,  left  hand  spindle  is  adjustable. 
and  speed  can  IH-  varied  from  11)00  to  4000  rpin  to  imure  maxi- 
mum pnxhiction  cliiciciicy  regardlcs*  of  M/C  of  hole. 

A  new  type  of  foot  treadle  in  which  a  quadrant  allow* 
to  move  the  table  in  a   straight   line  eliminates   much   ol    the 


78 


FM.AST1C& 


OCTOHKR  191B 


drudgery  of  conventional  foot  feed  machines.  Raising  and  lower- 
ing the  table  does  not  change  the  position  or  adjustment  of  the 
treadle. 

Spindles  operate  freely  in  anti-friction  bearings  with  elimina- 
tion of  all  gears (593) 


Attachments  Convert  Presses 

The  Hy-Speed  Press  Co. 

1715  W.  Lake  St.,  Chicago  12,  111. 

A  set  of  attachments  which  will  convert  a  conventional  hydrau- 
lically  operated  transfer  press  into  a  vertical  injection  mold- 
ing machine  in  a  few  hours  has  been  devised.  This  equipment  is 
available  for  transfer  presses  which  range  from  SO  to  400-ton 
capacity.  The  capacity  of  the  converted  unit  will  vary  in  direct 
proportion  to  that  of  the  original  unit.  Attachments  are  easily 
removable,  so  that  the  press  can  be  used  again  as  a  transfer 
molding  unit (594) 


Low-Range  Tester 

W.  C.  Dillon  &  Company,  Inc. 

5410  W.  Harrison  St.,  Chicago  44,  111. 

Especially  built  for  lighter  materials  or  small  finished  items, 
this  new  tester  has  4  separate  capacities  incorporated,  each  avail- 
able instantly,  and  shown  individually  on  its  large  dial:  0-10  Ib 
in  1-oz  dial  divisions  ;  0-25  Ib  in  2-oz ;  0-50  Ib  in  4-oz ;  and  0-100 
Ib  in  8-oz.  Its  lower  grip  travel  is  continuously  variable  from 
9"  to  19"  per  min.  It  also  offers  Yz  to  1%  accuracy,  pendulum 
action,  max-load  reading,  elongation  gauge,  stress-strain  recorder, 
and  other  features. 

Overall  height  of  the  unit  is  fi.V :  net  weight,  162  Ib (595) 


For  Marking  and  Code  Dating 

Adolph  Gottscho,  Inc. 

1  Hudson  St.,  New  York  13,  N.  Y. 

Portable  and  adjustable,  the  Markomatic  No.  9C  is  said  to  be 
adaptable  to  mark  objects  on  almost  any  conveyor  and  packag- 
ing or  material  handling  machine. 

This  unit  may  mark  as  frequently  as  80  imprints  per  min.  Ob- 
ject speed  may  be  up  to  100  ft  per  min,  and  a  moving  object  re- 
ceives its  imprint  from  a  flat  die  without  smudge  or  blur.  By 
merely  placing  the  Markomatic  No.  9C  and  locating  the  switch, 
marking  is  placed  precisely  on  the  object.  Regular  spacing  be- 
tween or  indexing  of  objects  is  not  required,  and  no  development 
is  necessary. 

This  unit  stands  50"  high (596) 


High-Speed  Dissolver 

The  Cowles  Company 
Cayuga,  N.  Y. 

Operating  on  a  new  high-speed  principle  that  introduces  com- 
ponents of  laminar  flow  and  interface  shear,  a  new  high-speed 
dissolver  has  proved  to  be  from  2  to  20  times  faster  on  standard 
dissolving  and  dispersing  operations  by  exposing  broad  areas  of 
molecular  contact  between  the  solvent  and  solute,  and  subjecting 
every  particle  of  material  being  treated  to  molecular  tension  and 
scrubbing  action. 

Of  the  two  models  now  in  production,  one  has  the  tank  per- 
manently incorporated  in  the  unit  with  capacities  of  100  to  500 
gal.  The  other  has  an  elevating  head,  designed  for  use  with 
user-furnished  portable  tanks (597) 


New  Electronic  Woodwelder 

Shortwave  Plastic  Forming  Co. 
2921  Alameda  St.,  Burbank,  Calif. 

Designed  particularly  to  enable  the  wood-working  industry  to 
work  to  best  advantage  with  the  new  plastics  adhesives,  the 
IVoodwclder  is  said  to  establish  an  entirely  new  principle  in  the 
electronic  curing  of  synthetic  resin  glue  lines.  Whereas  in 
ordinary  high  frequency  equipment  it  is  necessary  to  place  elec- 
trodes on  each  side  of  the  glue  line  for  curing  purposes,  the 
Woodivelder  need  only  be  applied  to  the  face  surface. 

When  placed  on  the  face  surface,  this  unit  will  cure  the  glue 
line  through  stock  as  far  as  1"  distant  from  the  electrodes. 
Current  is  transmitted  from  one  electrode  down  through  the  glue 
line  and  back  up  to  the  other  electrode,  thus  effecting  a  complete 
circuit  and  curing  the  resin  adhesive (  598 ) 


How  DME  Standardized 
Service  Gives  You  .  .  . 

FAST 
DELIVERY 

.  .  .  On   Mold   Parts  and 

Mold   Makers'  Supplies 

FROM  TWO  PLANTS! 

10  MINUTES  after  your  order  is  received  we  start 
filling  it.  We  have  most  everything  you  need 
in  stock  ...  READY  FOR  QUICK  DELIVERY 
FROM  OUR  DETROIT  OR  NEW  JERSEY  PLANTS. 


Standard 
Mold   Bases 

Wide  range  of 
standard  mold 
bases  and  parts 
.  .  .  will  save  you 
money,  i ncrease 
production.  Write 
today  for  catalog. 


Complete  Line 

of 
Mold   Makers'  Supplies 

•  EJECTOR   PINS 

•  SOCKET  HEAD  SCREWS 

•  FLAT  HEAD  SOCKET 

CAP  SCREWS 

•  LEADER   PINS 

•  LEADER  PIN  BUSHINGS 

•  DOWEL  PINS 

•  SHOULDER  SCREWS 

•  SOCKET  SET  SCREWS 

•  SPRUE  REAMERS 

•  TAPERED  MILLING  CUTTERS 

•  ABRASIVES  Tapered 

Milling 

WRITE    TODAY    FOR    FREE 

.    CATALOG:  DEPT.  PI 


DETROIT    MOLD 
ENGINEERING    COMPANY 

DETROIT   12        •        MICHIGAN 
HILLSIDE  (Near  Newark)  N.  J. 


OCTOBER  1946 


PLASTICS 


79 


EXPIRING  PATENTS 

brought  to  you 
each  week  by 

'PUBLIC 
DOMAIN 


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•&  2.  SIMPLIFIED  DRAWING 

ft  3.  MASTER  INDEX  TO  SAVE  YOU  TIME 

The  boll-point  fountain  pen,  the  double-edged  razor  blade,  aspirin,  • 
the  Stillion  wrench,  are  just  a  few  products  that  were  once  patented  j 
.  .  .  and  then  made  millions  after  their  patents  expired.  PUBLIC  ! 
DOMAIN  makes  it  easy  for  you  to  And  widely-used  items  such  as  these, 
as  well  as  obscure  ones  for  your  own  exploitation  without  payment  of 
royalties  or  license  fees.  It  is  o  practical  working  tool  and  a  valuable 

source  of  sound  ideas. 

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weeks    for    $10     Subscribe  now. 


SCIENTIFIC  PUBLISHING  CORPORATION 


Literature  Review 

High-Speed  Tableting  Machine 

Watson-StiUmon   Co. 
Hoselle.  N.  I. 

Its  100-ton  capacity  hydraulic  high-speed  tableting  mad; 
described  in  Bulletin  A'o.  643A  recently  issued  by  the  manufac- 
turer.    Illustrations,  specifications,  and  diagrammatic  drawings 
of  the  unit  are  included >  5"1'  i 

Engineering  and  Holding  Services 

Plastic  Manufacturers,  IDC. 
Fairfield  Ave  ,  Stamford,  Conn. 

A  folder  containing  bulletins  which  outline  briefly  the  com- 
pany's  facilities  for  molding  plastics,  and  tin-  services  they  offer: 
design  engineering,  mold  making,  molding  processes,  and  a--tm- 
bly.  Photographs  of  some  of  their  typical  molded  parts  and 
assemblies,  with  descriptions,  are  included (600) 


Reference  Chart  for  Bushings 

Creative  Plastics  Corporation 
963  Kent  Ave..  Brooklyn  S.  N.  Y. 

A  carefully-diagrammed  and  tabulated  chart  and  mechanical 
drawings  of  its  phenolic  insulating  grommet  bushings  is  now 
available  from  the  manufacturer.     The  chart  covers  all  dimen- 
sions, including  collars,  and  ranges  from  ft"  in    dia.  t. 
in   dia <  601 ) 

Bulletin  Describes  New  Plasticizer 

Armour  Chemical  Div.,  Armour  and  Co. 
1355  W.  31«t  St.,  Chicago  9.  111. 

The  use  of  aliphatic  nitrites  as  plasticizers  for  polyvinyl 
chloride-acetate  copolymers,  polystyrene  resins,  etc.,  is  discussed 
in  the  recently-issued  technical  bulletin  "The  Arneels  as  Plasti- 
cizers." 


Catalog  of  Clamping  Tools 

Knu-Vise,  Inc. 

2200  Eighth  St.,  Detroit  16.  Mich. 

A  16-page  condensed  compilation  of  its  general  catalog  has 
been  issued  by  this  company.  The  new  booklet  describes  and 
diagrams  each  classification  of  the  clamping  devices  produced 
!>y  Knu-Vise 


Induction  Motor 

The  Louis  Allis  Co. 
Milwaukee  7,  Wis. 

Rullclin  No.  720  fully  describes  construction  and  feature*  <.i 
this  company's  Type  OG  (protected  type)  Standard  Squirrel 
Cage  Induction  Motor.  Interesting  photographs  a<id  typical 
applications  for  the  unit  are  included  in  the  12-page  attractive 
bulletin (604) 


Plastics  Heating  Ovens 

The  G.  S.  Blodgett  Co.,  Inc. 

SO  Lakeside  Ave..  Burlington,  Vt. 

Four-page  file-size  folder  describes  the  application  ot 
gas-fired  ovens  in  the  plastics  industry.     Some  of  the  operations 
which  they  perform  arc  curing,  heat  molding,  drying  and  pla»- 
tici/ing  of  preforms,  preform  heating  of  acrylic  resins.  impriK- 
nation,  etc.    These  ovens  are  claimed  to  provide  controlled 
speedily  and  conveniently 


614  WEST  49th  STREET 


NEW  YORK  IV,  N.  Y. 


i 


Automatic  Turning  Machine 

The  Monarch  Machine  Tool  Co. 
Sidney,  Ohio 

Describing  the  new  I  ni-Matic  lathe  currently  KOMIR  into  pro- 
duction, Bullflin  \fi.   I7i>l  use-,  a  succession  of  photographs  to 
illustrate    the    various    inai Innint    ~ct  ups    possible       I  Utlru.il 
features  ami  timing  devices  incorporated  in  the  new   lathe  are 
•lisi  nssed. 

This  attractive  .'«>  pan"1  1'iilli-tin  is  reproduced  in  three  colors. 
and  is  spiral  bound  for  convenience  in  handling  ,  UK.I 


so 


PI.ASTMCS 


(MTOUEK   1946 


ENGINEERING 

Jlett&i 

By  LEWIS   WINNER 

Market  Research  Engineer 

Bonding  Processes 

The  development  of  bonding  techniques  has  been  of  major 
importance  to  plastics  progress,  providing  a  wide  variety  of 
plastics  materials  with  characteristics  of  glass,  metal,  cloth 
and  wood.  Bonding  processes  have  also  contributed  to  the  im- 
provement of  equipment  and  components,  particularly  in  the 
electrical  field.  The  efficiency  of  commutators,  fuse  panels, 
sockets  and  electric  irons  has  been  materially  improved  because 
of  advanced  plastics  bonding. 

Recently,  a  new  form  of  lightweight  aircraft-storage  battery 
construction  was  evolved  with  a  plastics-aluminum  sheet-bonding 
process.  The  process,  developed  by  Joseph  Charles  Duddy, 
Philadelphia,  permits  coating  of  an  aluminum  container  with 
a  copolymer  of  vinyl  chloride  and  vinyl  acetate  resulting  in  a 
metallic  unit  that  is  said  to  be  acid  and  alkali  resistant,  abra- 
sion resistant,  and  to  display  quite  a  high  dielectric  characteristic. 

In  previous  attempts  to  use  lightweight  aluminum  containers 
a  rubber  lining  was  employed  to  prevent  metallic  corrosion. 
This  procedure,  however,  proved  not  only  to  be  very  expensive 
but  produced  a  battery  that  was  quite  heavy. 

The  plastics  lining  is  applied  by  spraying.  In  preparing  |he 
surfaces  for  spraying,  the  aluminum  is  dipped  into  a  solution 
of  phosphoric  acid  which  etches  the  aluminum  and  provides  a 
deposit  of  aluminum  phosphate  as  a  base  for  coating.  To  this 
treated  surface  a  prime  coat  of  resin  paint  is  applied  by  spray- 
ing at  an  air  pressure  of  80  to  100  psi  or  a  paint  pressure  of  2 
to  5  psi.  This  resin  paint  consists  of  solvent  naphtha,  benzine, 
xylol  or  toluol,  chlorinated  rubber,  and  titanium  and  silica  pig- 
ments. After  the  initial  coat  dries,  an  intermediate  coat  is  ap- 
plied to  form  a  bond  or  adhesive  base.  This  intermediate  coat- 
ing consists  of  a  vehicle  of  approximately  60%  butyl  acetate  and 
40%  methyl  isobutyl  ketone;  vinyl  solids,  and  a  pigment  con- 
sisting of  sand,  titanium  oxide,  lithopone  and  graphite.  To 
keep  this  film  soft,  a  plasticizer  is  added ;  dibutyl  phthalate,  60  cc 
per  gal  of  solution.  The  intermediate  coat  is  sprayed  on  with  an 
air  pressure  of  approximately  40  psi  and  a  paint  pressure  of  IS 
psi. 

To  these  lining  bases  are  applied  three  seal  coatings.  The 
first  coat  consists  of  14%  to  17%  of  vinyl  solids,  3.5%  of  ap- 
proximately dibutyl  phthalate  and  79.5%  to  82.5%  of  mesityl 
oxide  solvent.  This  is  applied  at  the  relatively  low  air  pressure 
of  20  to  40  psi.  After  the  coating  has  dried,  the  second  seal 
is  applied ;  22%  of  vinyl  solids,  4.5%  of  dibutyl  phthalate,  .75% 
carbon  black,  and  72.75%  of  mesityl  oxide.  This  is  sprayed 
on  with  an  air  pressure  of  about  30  to  40  psi.  After  drying, 
a  third  seal,  using  the  same  materials  as  in  the  second  seal,  is 
sprayed  on.  The  container  is  then  air-dried  for  from  8  to  24 
hr,  and  baked  at  a  temp  of  approximately  200 °F  for  from  \l/i 
to  2  hr.  This  is  a  low-temperature  bake  to  rid  the  coating  of 
any  excess  solvent.  Since  the  temperature  is  below  the  boiling 
point  of  the  solvent,  some  solvent  is  retained,  and  it  is  this 
which  acts  as  a  plasticizer  and  provides  the  coating  with  ab- 
rasion-resistance and  toughness. 

Under  test  this  lining  was  found  to  withstand  a  voltage  stress 
of  at  least  500  v,  a.c. 

New  Antistatic  Treatment 

Antistatic  control  in  plastics  has  been  an  intriguing  subject. 
prompting  the  development  of  several  interesting  solutions.  In 
one  procedure,  antistatic  treatments  have  been  applied  to  fila- 
ments, fibres,  yarns,  woven,  knitted  and  felted  fabrics,  prepared 
from  water-insoluble  vinyl  resins,  formed  by  the  polymerization 
of  at  least  one  vinyl  compound  including  a  vinyl  halide.  The 
process,  based  on  a  discovery  by  William  N.  Stoops,  South 
Charleston,  West  Va.,  provides  for  a  treatment  with  one  or 
more  highly  basic  water-dispersible  polyalkylene  polyamines 
having  average  macromolecular  weights  of  at  least  300.  (The 
molecular  weights  of  the  polymers  are  determined  by  the  ebul- 


available  m  m 

beautiful  cola •••,  and 

for  every  purpose. 


l)o  not  accept  substitutes. 
There  is  only  one  plistk 
—CELLO-PLAtTlC. 


Brings  New  Colorful  Beauty  ana  Durable  Protection  to 
FLOORS  *  WOODWORK  *  WALLS  *  EXTERIORS 


Plastic  is  now  prepared  in 
liquid  paint  form  for  use  in 
home,  office,  store,  and  facto ry . 
This  has  come  about  through 
the  formulation  of  synthetic 
resins  with  specially  processed 


oils  combined  with  the  finest 
paint  pigments.  ACello- Plastic 
product  is  available  for  almost 
any  type  of  finish  or  surface. 
Does  not  chip  or  crack! 


BRILLIANT*  SMOOTH  *  TOUGH  *  DURABLE 

Fl  OOR*i  Cello-Plastic  /transparent/  is  i  non-skid  plastic 
ri»wwi*<*  finish  for  all  types  of  floors.  This  amaring  new 
treatment  gives  floors  a  "cellophane-like"  Plastic  finish.  Eliminates  pores  that 
absorb  dirt,  thus  making  floors  easy  to  clean.  Ideal  for  all  surfaces  including 
wood,  concrete,  linoleum,  asphalt,  tile  rubber,  composition,  etc.  Eliminate* 
waxing  and  polishing.  Unexcelled  for  marine  use. 

EXTERIOR      Tll's  m°dern  finish  is  a  severely  tested  product 
™  **    I    fc  IV  I   w  •*     that  surpasses  old  fashioned  type  house  paints. 

Pigmented  with  Titanium  Dioxide,  the  whitest  and  best  covering  pigment. 

combined  with  kettle  processed  linseed  oils  and  plastic  resins,  it  makes  a  rich, 

colorful,  lasting  coating.  Makes  homes  and  buildings  outstanding.  For  use  on 

wood,  stucco,  brick  or  shingle. 

INTERIOR     Brings  new  glamour  into  homes — protect  floors, 
1   *•*•**•*    woodwork,   furniture,  etc.,  with  its   long-lasting, 
"cellophane-like"  Plastic  finish.  Easy  to  apply — flows  smoothly — leaves  no 
brush  marks — self  leveling. 

Inquiries  from  Exporters  and  Dealers  Solicited 

Product  liability  underwritten  by  tne  of  America's 
largest  insurance  companies. 


CELLO-PLASTIC  CHEMICAL  CO. 

417-419  BLVD.  OF  ALLIES,  PITTSBURGH  19,   PA. 


OCTOBER  1946 


PLASTICS 


81 


BINZOYI 


ROXIDI 


lioscopic  method,  by  measuring  the  boiling  point  elevation 
known  amounts  of  polymers  in  solution  in  methyl  alcohol,  ge 
erally  in  amounts  forming  a  3Vc  to  6%  solution  of  the  polymer.] 

In  applying  an  antistatic  treatment  to  dyed  hosiery,  knit 
from  vinyl  resin  yarns,  the  hosiery  was  immersed  for  45 
in  an  aqueous  solution  of  0.2%  of  a  polyethylene-mine  havin 
an  average  molecular  weight  of  900,  0.5%  of  a  sodium  salt 
the  sulfate  ester  of  3,  with  9  diethyltridecanol-6  as  the 
ting  agent     Temperature   of   solution   was   between   60° 
65° C.     After  the  treatment  the  hosiery  appeared  to  be 
static  even  after  ten  washings  with  soap  and  water.    The  re 
used  iii  the  hosiery  was  produced  by  the  conjoint  poly 
tion  of  vinyl  chloride  and  vinyl  acetate. 

Wetting   agents   that   may   be   used   in   this   process    inch 
sodium  hexadecyl  sulfate,  sodium  lauryl  sulfate  and  lauryl 
cohol. 

It  is  said  that  this  treatment  does  not  substantially  redu 
tensile  strength,  flexibility,  elasticity  or  resistance  to  chemical, 
bacterial  and  fungus  sources. 

Scratch-Resistance 

With  the  successful  production  of  clear  glass-like  plastics  in 
varied  forms,  the  need  for  scratch-resistant  surface  control  be- 
came extremely  important,  prompting  the  development  of  sewH 
eral  effective  treatment  methods.  Of  current  interest  is  a 
process  developed  by  Max  F.  Bechtold,  Wilmington.  1  'el .  for 
use  on  methyl  methacrylate  polymer  sheets.  Mr.  Bechtold 
secures  a  scratch- resistant  surface  by  applying  a  solution  of 
ethyl  silicate,  hydrolyzed  with  an  amount  of  water  equal  to  at 
least  15''<  of  the  weight  of  the  ethyl  silicate,  and  a  vinyl  acetate 
polymer  containing  1  part  by  weight  to  1-99  parts  of  the  silicate 
content  of  the  solution. 

In  previous  methods  it  was  not  possible  to  secure  complete 
scratch  resistance  because  of  the  inherent  softness  of  the 
organic  coating  materials,  and  the  molecular  weakness  and 
porosity  of  the  resulting  deposits. 

In   preparing   a   scratch-resistant   sheet,   the   sheet   is   dipped 
into  the  coating  solution  for  two  min.,  and  then  drains 
dried  for  about  8  min.  in  a  room  with  relative  humidity  01 
The  coated  sheet  is  then  placed  between  sheets  of  chromium- 
plated  polished  steel.    This  sandwich  is  inserted  in  a  mold  and 
the  mold  is  placed  between  the  heated  platens    (155°C)    »i   a 
hydraulic  press.     A  pressure  of  1110  psi  is  immediately  applied 
to  the  sandwich  by  rapidly  closing  the  platens,  which  will  cool 
to  about   140' C  shortly   after  the   mold  is   inserted.   In-ca 
the  heat  absorbed  by  the  mold,  although  a  heat-input  control 
can  be  used  to  return  the  temperature  to  150"C  in  approxii 
5  min. 

When  this  temperature  is  reached,  the  heat  is  turned  off  and 
the  mold-sandwich  assembly  and  platens  cooled  to  80° C  within 
25  min.     The  pressure  is  then  released  and  the  sandwich 
srmMed. 

Another  method  uses  a  sheet  of  heat-treated  methyl  met! 
late  plasticized  with  10%  dibutyl  phthalate  and  cleaned  with  a 
lint-free  cloth  dampened  with  nicthanol.  The  sheet  is  immersed 
in  the  coating  solution,  which  lias  aged  M  to  90  hr.  for  15  min, 
and  withdrawn  by  a  mechanical  windup  at  a  uniform  rate  of 
per  min.  The  coated  sheet  is  then  withdrawn  into  air  at  2t  <  . 
i  dative  humidity,  and  permitted  to  drain  and  dry  for  20  min. 

The  coated  resin  sheet  is  now  mounted  between  <\r\ 
plates,  and  the  sandwich   is   wrapped   in   paper  and  placed   in  a 
flexible  Lair  which  can  be  evacuated  and  will  withstand  hot  oil 
under  pressure.     This  bag  is  evacuated  to  about  25"  of  mercury, 
sealed  off  and  placed  in  an  auttx-lave  heated  and  cooled  by  circu- 
lating oil.     The  bag-sandwich  assembly  is  then  subjected  to  a 
heating-run-cooling  hot -pressing  cycle.     Kemoval  from  the  bag 
follows  and  the  sandwich  is  allowed  to  cool  in  room  air. 
a!«Mit  1  min,  the  sandwich  units  dissassemhle  s|>oiitanrous|\.  <l»e 
in  differences  in  thermal  contraction 

In  one  test,  the  surface  of  a  treated  sheet,  scoured  will 
wool  ami  allowed  to  remain  in  a  hot  water  bath   (60°C)   for 
.?(i«l  hours,  still  retained  its  clear-glass  qualities. 

finishing,  spraying,  squeegeeing  or  dipping  may  also  be  used 
lo  apply  the  coating  solution  When  dipping,  it  is  usually  diffi- 
cult to  control  the  coating  thickness.  However,  a  controlled 
withdrawal-rate  procedure  can  be  applied.  (  oatings  of  from 
US  to  5  microns  have  JXTII  found  to  IK-  surprisingly  cfi 
for  scratch  resistance.  The  coatings  have  also  proved  useful 
in  minimi/ing  snrfai  ••  static  cli,, 


Pf,  ANTICS 


(HTOIiKK  1916 


overseas 


Indicative  of  the  rate  of  progress  of  Great  Britain's  plastics 
industry  in  recent  years  are  some  notable  figures  revealed  re- 
cently by  a  leading  British  plastics  authority.  Compiled  on  the 
basis  of  statistical  data  available  to  date,  these  figures  show  that 
while  the  industry's  prewar  capital  investment  of  $20,000,000  has 
grown  to  well  over  $100,000,000,  its  annual  production  output 
within  the  same  period  of  time  has  increased  from  27,000  metric 
tons  to  something  like  80,000  metric  tons. 

Measured  against  Britain's  population  total  of  some  45,000,000, 
these  comparative  figures  indicate  a  per  capita  gain  in  consump- 
tion of  plastics  from  1.1  Ib,  prewar,  to  approximately  2.9  Ib, 
postwar. 

According  to  this  authority,  the  rapid  expansion  in  British 
plastics  consumption  is  due  partly  to  war-stimulated  develop- 
ments in  plant  facilities  for  converting  raw  materials  into  pow- 
ders, resins  or  manufactured  goods  and  partly  to  aggressive 
promotion  and  merchandising,  on  the  part  of  manufacturers,  job- 
bers and  dealers. 

Travel  Applications 

A  new  plastics  has  been  developed  as  the  result  of  numerous 
experiments  and  tests,  conducted  in  Clyde  shipbuilding  yards  to 
obtain  a  material  suitable  to  replace  wooden  deck  plankings  in 
ocean-going  vessels. 

Said  to  be  springy  underfoot,  restful  to  the  eye  in  sunglare. 
fireproof,  and  impervious  to  temperature,  climatic  conditions,  oil 
and  grease,  the  new  planking  material  is  already  being  fitted  into 
a  number  of  ships,  including  the  32,000-ton  luxury  liner  Maure- 
tania. 

The  crack  British  "Golden  Arrow"  boat  train  connecting  Eng- 
land with  France  now  includes  an  all-plastics  railway  buffet  car. 

Designed  by  the  British  Bakelite  Company's  Industrial  design 
unit,  the  car  is  a  converted  Pullman  coach  fitted  with  laminated 
plastics  walls,  partitions,  bars  and  tables,  transparent  plastics 
display  cases  and  lighting  fittings  and  curtains  of  translucent 
vinyl. 

The  still  comparatively  small  British  metal-plastics  furniture 
industry  is  thriving.  A  new  factory  was  recently  added  for 
the  exclusive  production  of  20th  century  styled  furniture,  by 
Hunting  Aviation  Ltd.,  in  Caernavon,  Wales. 

Designed  for  the  most  part  with  restraint,  beauty  and  dignity, 
this  new  type  of  furniture  is  rapidly  establishing  a  reputation  for 
itself. 

As  the  result  of  a  prolonged  series  of  successful  experiments 
with  rubberized  rayon  plastics  tire-casings,  cotton  may  be  ousted 
from  automobile  tires. 

Extensive  tests  undertaken  by  a  prominent  British  tire  manu- 
facturer provided  conclusive  evidence,  it  is  reported,  that  rubber- 
ized rayon  tires  strengthened  by  plastics  are  stronger  and  more 
heat  resistant  than  the  cotton-strengthened  type. 

Polystyrene  Foil 

P  British  Xylonite  Ltd.,  the  original  producer  of  Polystyrene 
(Distrene)  is  now  engaged  in  the  manufacture  of  small  quantities 
of  this  material  in  the  form  of  rolls  of  foil  ranging  from  s/z" 
to  12"  in  width  and  from  2/1000"  to  8/1000"  in  thickness. 

The  company  claims  that  because  of  the  extraordinarily  fine 
dimensions  in  which  polystyrene  foil  can  be  made  it  is  destined 
eventually  to  replace  mica,  glass  and  gutta-percha  as  the  insula- 
tion material  in  high  precision  electric  and  radio-electronic  equip- 
ment. 

Novel  Uses 

A  new  use  for  plastics  was  found  by  Misha  Black,  industrial 
designer,  while  designing  a  lightweight,  easily  transportable  and 
adjustable  travel  information  unit  for  the  London  Passenger 
Transport  Board. 


Fast-working  Armour  Abrasives  Mean  More  Production! 

Today's  growing  demand  for  plastic  products 
calls  for  volume  production.  To  get  it  you  need 
the  fastest  tools  and  the  best  abrasives  possible. 

For  better,  faster  finishing  ...  in  removing  flash 
and  parting  lines,  in  smoothing  rough  spots  and 
mold  defects— in  any  sanding  operation ...  there  are 
specialized  ARMOUR  ABRASIVES  designed  to  do 
a  better  job  at  less  cost.  They  are  available  in  rolls,  belts, 
discs,  sheets  and  in  special  forms  for  special  jobs. 

It  will  pay  you  to  call  on  Armour's  experienced 
technicians.  They  will  gladly  help  you  choose  the 
abrasives  and  methods  which  do  your  jobs  best. 


ARMOUR 


WORKS 


Division  of  Armour  and  Company       •       1355  W.  31st  St.,  Chicago  9,  III. 


OCTOBER  1946 


rt.ASTMCS 


83 


FASHIONS 
A  BETTER 
HANDBAG 


Handbags  woven  of  SARAN  BY  NATIONAL  are  meeting 
enthusiastic  response  in  the  nation's  smartest  specialty  shops. 
Creations  such  as  this  one  by  Garay  &  Company,  New  York, 
are  fashioned  in  a  variety  of  color  combinations  and  inter- 
effing  textures.  SARAN  fabrics  won't  stain  or  soil  easily  .  .  . 
need  only  a  damp  cloth  to  keep  them  clean  and  fresh.  This 
is  but  one  of  many  similar  applications  in  which  SARAN  BY 
NATIONAL  has  scored  a  huge  successl 

Who*  possibilities  docs  SARAN  hold  for  your  prod- 
uct? Our  technical  facilities  are  available  for  study 
and  suggestion.  Write  today) 


/TV 


NATIONALS? 


For  PANTOGRAPHIC  ENGRAVING 

ON  PLASTICS 

Panto      Engraven, 

rugged  and  precision-built, 
for  accurate  and  clean-cut 
engraving  on  plastic 
and  metal  products. 
Depth    Regulator, 
available    with    all 
models,  produces  a 
uniform  depth  ol  engraving 
on    Irregular    and    curved 
surfaces.     Forming    Guide, 
on  the  UE-3  only,  for  use 

Model  UE  3.  spherical,  and 

Also  lighter  fjf          beveled  surfaces. 

UE.  UE-2. 

Engraving  cutters,  master  copy  type,  fixtures,  and  end- 
less round  belts,  lor  all  types  ol  engraving,  die  and 
mold-cutting  machines. 

MODEL  CG  GRINDER 
for  quick  and  accurate 
sharpening  of  engraving 
and  routing  cutters. 

»  Catalog 
on  request 

H.  P.  PREIS  ENGRAVING  MACHINE  COMPANY 
HIE  SUMMIT  STREET  NEWARK  4.  MEW  JERSEY 


PANTO  MARKING  EQUIPMENT 


The  unit  consists  "i  a  thin  veneer  cast  ut  r  :u-  plastics  ph 
l*>ii(lrd  to  a  metal  backing  by  a  re-in  adhesive  and  has  in- 
brightly  colored,  toned  and  enameled  plastic*  sliding  |>ancl  indi- 
slunviiiK  traffic  maps,  time-table-.,   routes   and  incidental 
information  of  use  to  passengers. 

Designed  with  an  eye  to  mass  production,  this  unit  is  to  be 
installed  in  London  tube  trains,  buses,  trolley-buses  and  coaches. 

A  novel  range  of  temperature-indicating  changeable  paints,  for 
controlling  and  checking  heat-treatment  in  plastics  molding  ma- 
chinery, has  been  developed  by  Synthetic  &  Industrial  Finishes 
Ltd..  Watford,  Herts. 

Called  Thcrmindfx,  these  paints  change  color  at  pre-deter- 
mined  melting  points  appropriate  to  the  working  temperatures 
of  articles  to  which  they  are  applied,  indicating  visually  whether 
or  not  proper  heat-treatment  has  been  effected. 

New   Developments 

Plastics  coins  are  now  being  issued  to  the  British  occupation 
forces  in  Germany. 

Stamped  out  of  tough  phenolic  sheet  material,  the  coins  are 
all  of  small  denominations  and  probably  represent  the  first  plas- 
tics currency  in  recorded  history. 

Britain's  austere  Royal  Mint,  however,  is  playing  no  part  in 
the  venture:  a  private  plastics  manufacturing  company  is  re- 
si*msible  for  this  production. 

Western  Incubators  Ltd.,  East  Hanningfield,  Kssex.  has  an- 
nounced that  a  plastics  egg  incubator  has  been  added  to  the  line 
of  products  manufactured  by  that  company 

Developed  in  co-operation  with  British  Industrial  Plastic- 
Ltd.,  of  London,  the  new  incubator  is  completely  enclosed  within 
a  urea-bonded  plastics  housing  for  protection  against  atmospheric 
conditions,  mold,  vermin,  etc. 

Coal  By-Product  from  U.  S. 

Britain's   acute   shortage  of  coal    wa«    recently   spotlighted    in 
an  interesting  admission  made  by  H.  V.   Potter,  managing  di- 
rector of  British  Bakclite  Ltd..  at  the  annual  general  me.  • 
his  company  in  London. 

Mr.  Potter  said  that  his  company's  activities  were  now  so 
seriously  handicapped  by  the  shortage  of  various  raw  materials, 
particularly  phenol,  that  it  lias  IH-CII  necessary  to  itn|>ort  phenol 
from  America,  despite  its  being  a  by-product  of  coal. 

Swedish   Plastics   Federation  Formed 

As  a  result  of  marked  expansion  of  the  plaMics  industry  in 
Sweden  during  the  war.  and  the  accompanying  increase  oi  the 
number  of  companies  and  individuals  interested  in  the  held,  an 
organization  has  been  formed  by  a  number  of  plastics  manufac- 
turers in  that  country  "to  deal  with  matters  of  common  in:- 
1  Srcnska  Konstharlslorfniniifii  (The  Swedish  I' 
Federation)  and  more  readily  identified  as  SPF.  this  group  was 
founded  in  February  1946  by  about  80  companies,  reprcscntum 
molders.  fabricators,  manufacturers  and  suppliers  of  raw  ma- 
terials, synthetic  resins  and  glues,  molding  jimvders  and  com- 
pounds, and  laminated  materials  Manufacturers  of  molding  and 
injection  machinery  have  also  become  memlx-rs  of  the  organi/a- 
tion. 

Harry  Xystroin.  managing  director  of  the  Swedish  Mc.ttual 
Mfrs.  Association,  was  elected  president  of  the  SPF  for  the 
year  1'M'i.  with  I-'.rik  Killandcr,  managing  director  of  the  Skansa 
Attikfahrikens  Agentur  A  I'..  .1-  \  it  e  president,  and  the  Uwrd  of 
director-  consists  of  1"  incmlx'rs  representing  different  branches 
of  the  trade.  Jan  E.  Janson  is  executive  secretary 

The  aims  of  the  organization  include  working  for  continued 
improvement  of  the  technical  standard  of  the  indnsttv  :  working 
mit  standards  for  various  types  of  pla-lic-  and  estahlishmrnt  of 
.1  i. -111111011  nomenclature  for  the  industry;  and  dissemination  .-i 
reliable  information  concerning  pla-tic-  material-,  to  c.iii-umer- 
and  to  the  technical  trade 

V.iiions  r.immitlcr-  i'.r  stndx  .if  problem-  in  the  tield.  ami  for 
following  development  of  the  indti-try.  have  been  established 
within  the  SIM- 

Announcing  that  it  plans  to  t>e  of  service,  wherever  |H>SM< 
.ill  compaiiie-  and   individuals   interested  in  pla-lic-  and   : 
lie-Id-,  in  Sweden,  the  new    Federation  advi-e-  that  contact  with 
v.iti.-iis   research   institutions   ami   <  lovernment   deparlmn  • 
•Ji-lied   for   the  en  ordinal!-'  .irch  and   - 

.11  In 


s 


(HTOBKH   I!)  16 


PROBLEMS  in 


plastics 


Problems  and  questions  may  be  submitted 
to  this  department  for  answering  by  the  tech- 
nical editors  or  specialists  in  the  industry. 

For  advertising  purposes,  we  are  desirous  of  having  molded 
a  paperweight,  with  our  company  trademark  on  it.  Is  there  a 
thermoplastic  material  which  has  a  specific  gravity  of  2  or  over, 
and  also  has  good  shock  resistance?  J.E.,  San  Francisco,  Calif. 

Vinylidene  chloride  ("Saran")  has  the  highest 
specific  gravity  available  for  a  thermoplastic,  fr-om 
1.65  to  1.75.  Its  impact  strength  ranges  from  about 
0.3  to  1. 

There  are  other  thermoplastics  ivhich  offer  much 
hit/her  impact  strengths  (such  as  ethyl  cellulose, 
ivhose  impact  strength  ranges  from  0.6  to  11.5),  but 
the  specific  (/rarity  of  this  material  is  lower  than 
that  of  "Saran." 

*  *     * 

We  are  desirous  of  producing  inexpensive  cast  novelties  which 
will  resist  chipping  and  breaking  more  than  articles  made  of 
plaster  of  Paris,  hut  which  could  be  used  in  making  similar  items. 
What  material  do  you  suggest?  L.H.L.,  Toledo,  Ohio. 

We  think  a  cnmhinittiun  plastics  resin-plaster  of 
Paris  material  ivmtld  satisfactorily  fill  your  needs. 

*  *     * 

What  plastics  material  do  you  advise  to  be  used  for  outdoor 
furniture  that  will  withstand  considerable  punishment,  and  which 
could  he  left  outdoors  in  all  weather  without  harmful  effects? 

D.B.G.,  Lima,  Ohio 

A  plastics  ic'iV/i  fibrous-glass  reinforcement  would 
probably  best  fill  the  requirements  you  set  forth. 

*  *     * 

\\  hat  types  of  coatings  are  applied  to  cloth,  and  what  are  the 
methods  of  application?  J.K.,  Argo,  111. 

There  are  six  general  types  of  coatings  as  applied 
to  cloth:  cellulose  ester,  such  as  nitro-cellulose, 
ethyl  cellulose,  cellulose  acetate,  cellulose  aceto- 
butyrate;  vinyl  resin  coating,  such  as  copolymcrs 
of  vinyl  acetate  and  vinyl  chloride,  polyrinyl  butyral 
mill  polyvinyl  alcohol;  oil  coating;  oil  in  resin  coat- 
ing, as  varnish  cambric  and  coaling  for  laminated 
plastics;  starch  and  casein;  and  rubber  and  syn- 
thetic rubber  coatings. 

There  are  four  methods  of  applying  coatings  to 
cloth:  spreader  or  doctor  knife  coating,  calendering, 
dipping,  and  rolling. 


ATTENTION- RECORD  MANUFACTURERS! 

New  INDUSCO  75  Ton  and  100  Ton  Semi-Automatic  Phonograph  Record 
Pressing  Units,  Comprising  Presses,  Pumps,  Motors,  Hydraulic,  Steam 
and  Water  Valves,  Automatic  Timers  and  All  Accessories.  The  75  Ton 
Units  for  10"  and  12"  Shellac  and  10"  Vinylite  Records,— the  100  Ton 
Units  for  12"  Vinylite  Records.  Prompt  Deliveries. 

New  INDUSCO  157  Ton  and  400  Ton  Hobbing  Presses,  12"  Daylight, 
Hardened  Steel  Anvils,  Each  Complete  with  Either  Hand  or  Power 
Driven  Pump  with  Necessary  Piping  and  Accessories. 

New  INDUSCO  75  Ton,  100  Ton,  175  Ton  and  225 
Ton  Molding  Presses,  Platen  Sizes  from  12"  t  12" 
up  to  30"  x  24".  Daylight  Openings  to  Suit. 

Various  Sizes  and   Capacities  of   Used,   Guaran- 
teed, and   New   Presses,   Pumps,  Accumulators. 
Prompt  Deliveries.     Full  Details  on   Request. 

Write.  Wire.  Phone 

INDUSTRIAL    EQUIPMENT   COMPANY 

873  Brood  Street  Nework  2,  New  Jersey 


Specialties 


OCTOBER  1946 


PLASTICS 


Co/cf-forgecf 
af  a  saving 


If  you  need  a  special 

rivet,  nail  or  threaded  part— and  soon— we  can  make  it  for 
you.  Cold-forging  offers  you  not  only  surprisingly  quick 
delivery,  but  a  substantial  saving  as  well. 

Steel,  Stainless  Steel,  Monel,  Brass,  Copper,  Bronze,  Alumi- 
num and  Aluminum  Alloys  are  everyday  materials  to  us. 
A  varied  stock  of  sizes  and  metals  is  available  to  serve  you. 

Both  economy  of  manufacture  and  strength  of  product  are 
obtainable  by  using  cold-headed  parts.  Send  us  a  sketch  or 
sample  of  your  part.  No  obligation.  Ask  for  free  catalog. 

JOHN  HASSALL,  INC. 

160  CLAY  STREET 
BROOKLYN   22,   N.   Y. 

Special  nails,  rivets,  screws 

and  threaded  parts 

85 


INJECTION  MOLDING 


The  versatile  capacity  o/  the  Reed-Prentite 
luM-U  Ox.  injection  molding  machine  healer  it 
well  illustrated  by  ihne  products. 

The  To>  •  '  *  Scat  body  (  a  ihot  weighing  over 
22  Or)  i*  produced  on  a  W  per  hour  cycle  by 
Eclipse  NoMvd  Products  COL,  Milwaukee,  for  the 
Hamilton  Mfg.  G*,  Two  Riven,  W  iHotuin. 

Another  Urge  plank  product,  the  hair 
dner  throud  (a  22  OL  shot),  is  made  by  the  same 
moldcn  for  the  Rilling  Corp..  Minneapolis,  on  a 
cycle  of  Approximately  39  per  hour. 

A  complete  range  of  machine  sizes  b  avail- 
able in  4.  6.  8.  12,  16  and  22  Oi-  capacities.  For  in- 
formation  and  descriptive  circular  write  Dept.  U. 


IK  mil's  uistST  •mncTiuis  ir  IIIICTIIR  MLIIK  MICIIRES 


tl/l 


rror 


VUe 


lize  in  tne  hard 


e  specialize  in 
chromium  platina  of  pla&tic 
lds  ana  dieA  to  a 


mou 


mirror 


CHROME  SERVICE 


Save  It  with  Chromium 

9350  GRINNELL  AVE.      •      DETROIT  13,  MICH. 
Plaza  3164 

1926         Ow  30th  Y«*r  at  D.p.n<UbU  Swrio*          1946 


Statistical  Data 

PLASTICS  and  synthetic  resin  shipments  and  consumption  for 
June,  as  reported  by  the  Bureau  of  the  Census,  fell  about 
UM>  million  pounds  below  the  total  poundage  for  May.  the  lirst 
time  since  February  that  a  monthly  total  was  less  than  that  of  a 
preceding  month.  Xot  only  was  the  59,297,130  Ib  figure  for 
June  umli-r  the  total  for  May,  but  it  also  was  lower  than  that 
fur  April  by  over  a  million  and  a  half  pound>. 

Only  in  a  comparatively  few  categories  were  there  inert-,. 
June,  namely:  (1)  cellulose  acetate  and  mixed  ester  plastics 
sheets,  including  all  gauges;  (2)  phenolic  and  other  tar  acid 
rt-Miis  used  for  laminating ;  (3)  phenolic  and  other  tar  acid  resin 
nuilding  materials;  (4)  polystyrene;  and  (5)  vinyl  mnldiuii  and 
extrusion  materials. 

Phenolic  and  other  tar  acid  resin  molding  materials  and  poly- 
-tyrene  are  still  making  sizable  increases.  The  former  took 
ijuite  a  jump  in  May,  and  June  shipments  and  consumption  ran 
about  700,000  Ib  above  those  for  May.  Polystyrene,  whir 
200,000  Ib  higher  in  May  than  in  April,  increased  nearly  480,000 
Ib  in  June. 

Molding  and  extrusion  materials  constitute  some  36,000,000 
Ib  of  the  59,297,130  Ib  total,  leaving  the  remaining  23,000.000  Ib 
to  be  accounted  for  by  resins  used  in  sheets,  rods,  and  tubes ;  in 
laminating;  adhesives ;  film;  textile  and  paper  coating:  and  mis- 
cellaneous uses.  Over  a  third  of  the  total  or  molding  and  ex- 
trusion compounds  is  supplied  by  phenolic  and  other  tar  acid 
resin  molding  materials,  which  in  June  reached  14,lfil/o4  Ib. 

The  statistics  below  represent  the  shipments  and  consumption 
of  plastics  and  synthetic  resins  as  reported  by  77  manufacturing 
companies  and  company  departments.  Data  for  synthetic  re»ins 
for  protective  coatings  are  not  included.  Shipments  include  data 
for  plastics  and  resins  manufactured  by  the  reporting  companies 
or  company  divisions  and  shipped  to  outside  users.  Consumption 
refers  to  the  plastics  and  resins  manufactured  and  used  by  the 
reporting  companies  or  company  divisions. 


Plastics  and  Synthetic  Resins  Shipments 
and  Consumption  (Ib) 


June 

May 

Hem 

1946 

194e 

Celtuloie  acetate  and  mixed  ester  plastics' 

Sheets 

Continuous  (under  .003  gauge)  

690,011 

627,583 

Continuous  (.003  gauge  and  upward).  .  .  . 

751,572 

591,277 

All  other  sheets,  rods,  and  tubes  

384,765 

424,612 

6,742,790 

7,251,398 

Nitrocellulose  plastics' 

Sheets  

864,420 

907,550 

Rods  and  tubes  

564,629 

624,857 

Phenolic  and  other  tor  acid  resins 

2,573,412 

1,809,303 

Adhesives  (dry  basis)  

996,569 

1,317,144 

Molding  materials'  

14,161,634 

13,453,292 

All  other  (dry  bam]'  

4,818,844 

5.437,693 

Urea  and  melamine  resins 

Adhesives  (dry  basis)  

2,596,207 

3,477,621 

Textile  and  paper  treating  (dry  basis)  

886,620 

890,270 

All  other  (dry  boils)-'  

145,115 

262,132 

Polystyrene'  

5,639,484 

5,159,798 

Vinyl  resins 

Sheeting  and  film'  

1,857,160 

2,375,298 

Textile  and  paper  coating  resins  (resin  con- 

tent)   

1,234,522 

1,397,337 

Molding  and  extrusion  materials  (resin  con- 

tent)   

4,978.168 

4,665,924 

Adhesives  (resin  content)'  \ 
All  other  (resin  content)'  

42,369,412 

•2.187,521 

Miscellaneous  plastics  and  resins 

Molding  and  extrusion  materials'-'  

4,850,236 

5,537.499 

All  other  (dry  basis)',*  

2,191,560 

2,837.187 

TOTAL  .......................  59,297.1  30     61.235.30J 


, 
*CofM*o*  b*  ihcrwft 


H«ri,  plaii»en»M,  and  •  tt*«d*f»    lfxciud*l  data  for  protective  coaling  r*tiM. 
ihcrwft  »*porot«lr  wtthov*  dbclo»ing  op*rationi  of  individual  *%*abl*»hm*nti. 
of  •«ttmoU,   2.8%   for  !••!.    4nclwd»i  data   for  »ftivl  c*Hwlot».  WTM  o*4 
m«Jomin*,  ocryfk  ocM, 
data  for  p*froUvm  rrt 


crrlfc  odd. 


. 

otrffeg  and   •strut.oo  ma'***!*. 
r**in*.   i*litvr*t,  and  mitc*1lon«ov« 


I*  I.. 1ST  I CS 


(XTOHKR   PMfi 


INDUSTRY  HIGHLIGHTS 


A  surface  coating  which  consists  of  very  finely  cut  particles 
of  cellophane  is  now  being  produced  by  Rayon  Processing  Co.  of 
R.  I.,  Inc.  Called  "cellophane  spangles,"  the  coating  imparts 
distinctive  sparkle  to  any  surface  to  which  it  is  applied,  due  to 
reflection  of  light.  Designed  to  be  used  in  applications  where 
flock  is  generally  employed,  these  "spangles"  can  also  be  applied 
to  textiles  by  dot  printing,  in  a  similar  manner.  A  distinctive 
crystalline  effect  is  achieved  when  the  material  is  used  as  a 
novelty  filler  for  colored  transparent  plastics. 


Recent  acquisition  of  the  Shoberg  Tool  Co.,  manufacturer 
of  precision  tools,  instruments  and  machines,  has  been  announced 
by  Barnes  &  Reinecke,  Inc.,  industrial  designers  and  engineers, 
Chicago. 

Supplementing  the  organization's  present  machine  shop,  and 
providing  additional  facilities  for  the  manufacture  of  the  special 
tools  and  machines  designed  for  clients,  purchase  of  the  Shoberg 
plant  is  part  of  the  Barnes  &  Reinecke  company's  expansion  pro- 
gram. 

It  is  further  announced  that  Fred  P.  Shoberg,  founder  of  the 
recently-acquired  company,  will  continue  as  president  of  Shoberg 
Tool  Co.,  a  Division  of  Barnes  &  Reinecke. 


A  change  of  address  has  been  announced  by  A  &  B  Plastics 
Co.,  Chicago,  which  is  now  located  at  936  W.  Madison  St. 


Operation  of  the  Feller  Engineering  Co.,  Pittsburgh,  has  been 
taken  over  by  Lake  Erie  Engineering  Corp.,  Buffalo,  N.  Y. 
Activities  of  the  former  Pittsburgh  concern  are  to  be  carried  on 


by  the  Lake  Erie  company  as  its  Feller  Engineering  Division, 
with  K.  Feller  as  general  manager,  headquartering  in  the  Empire 
Bldg.,  Pittsburgh. 


Advising  that  expansion  of  business  has  made  necessary  the 
acquisition  of  larger  quarters,  The  Towne  Mfg.  Co.,  New  Haven, 
Conn.,  has  announced  its  move  to  210  Meadow  St. 


New  chemical  engineering  facilities  for  the  investigation  of 
new  industrial  processes  and  products  on  a  pilot-plant  scale 
have  been  installed  at  Battelle  Institute,  Columbus,  O.,  and  it  is 
expected  that  additional  equipment  will  be  completed  by  the  end 
of  1946.  Laboratory  facilities  at  the  Institute  are  available  to 
organizations  interested  in  new  processes. 


Conversion  of  the  wartime  estef  plant  of  Reichold  Chemicals, 
Inc.,  Detroit,  to  the  manufacture  of  a  new  type,  low-priced  pure 
phenolic  resin,  has  been  virtually  completed,  according  to  advices 
from  the  company. 

The  announcement  adds  that  recent  technical  developments, 
inaugurated  during  the  conversion,  have  increased  efficiency  of 
operation  at  the  plant,  thereby  considerably  increasing  yields  of 
resin,  and  that  this,  plus  speeded-up  processing,  has  more  than 
doubled  the  company's  output  of  the  resin,  known  as  No.  2100 
Stiper-Beckatite. 


Opening  of  a  new  technical  laboratory  at  719  First  Avc., 
New  York  City,  has  been  announced  by  Witco  Chemical  Co.  It 
is  to  be  under  the  direction  of  Dr.  L.  H.  Cohan,  formerly  director 


More 


ACCURATE 
Service 


and  we  mean  it  ...  BECAUSE  ...  in 
our  NEW  PLANT  we  have  loads  of  extra 
elbow  room  .  .  .  AND  a  larger  staff  of 
competent  engineers  and  designers  .  .  . 
there  are  a  greater  number  of  expert  crafts- 
men .  .  .  AND  TOO  there  it  our  usual  high 
standard  of  quality  production  .  .  .  ALL 
UNDER  ONE  BIG  ROOF.  This  means 
.  .  .  more  ACCURATE  SERVICE  to  meet 
the  accumulated  needs  of  our  many  cus- 
tomers' Compression  and  Transfer  Molding 
Jobs  .  .  .  AND  PERHAPS  .  .  .  your  prob- 
lem too  .  .  .  why  not  call  us  to-day  .  . 
NO  OBLIGATION. 


ACCURATE 


MOLDING 
CORPORATION 


35-20     48th    AVENUE 
LONG  ISLAND  CITY  1 ,  N.  Y. 


OCTOBER  1946 


r L.  isrtcs 


87 


SLITTING 
CUTTING 

and  Rewinding  of  All 

•PLASTIC  FILM  and 
•COATED  MATERIALS 

from  l  ie"  and  Upward  in  Width 

•  PINKING 
•SCALLOPING 

•  FANCY  EDGES 

•  WELTING 

•  HEAT  SEALING 

Complete  Service 

INQUIRIES  AND  PROBLEMS 
ATTENDED  PROMPTLY 

WRITE  OR  PHONE  Now.' 

BENJAMIN  GOODMAN.. 

69  FIFTH  AVE.,  N.Y.  C. 


ALGONQUIN   4 


MECHANICAL 


RE-DESIGN 
for  PLASTICS  PARTS 

Sometimes    a    minor    change    in    design    enables 
you   to  increase  production  and   lower  molding 
coitt.   Small  changes  frequently  result  in  prod- 
uct improvement. 

We  are  old  hands  at  mechanical  re-deiign- 
ing.  Our  more  than  quarter  century  eipe- 
rience  may  help  you  overcome  problems. 


Con 


out   obligation,    is   wel- 


11   iullrtlf  r>4  without 


ckore*.     It  trlli  of  our  monr   i«rvic*i 


llm  \in  111:11 


MIW  YORK  10.  N.  Y. 


•  •f  rc-earch  lor  Continental  Carbon  Co.  a  Witco  subsidiary,  and 
the  announcement  adds  that  equipment  include-  the  most  modern 
of  facilities  for  studies  in  plastics,  paint,  nihber  and  general  chem- 
ical work. 


Announced  as  a  war-time  research  development  of  the  >..in- 
pany's  elastomer  division.  Electro-Technical  I'ruducts.  Inc., 
Nutley,  X.  )..  has  introduced  Elastomer  \<>.  10?.  de-critv, 
rubber-like  plastics  comix mnd.  The  new  product  is  available  in 
the  form  of  a  free-flowing,  viscous  material  having  a  100% 
solid  content  which  will,  it  is  said,  cure  and  |Milymeri/e  In  the 
simple  application  of  heat  without  pressure,  will  neither  shrink 
nor  expand  during  curing  process,  and  will  take  finest  detail-  of 
a  mold. 

Elastomer  No.  105.  according  to  its  makers,  has  unusual 
rc-i-taiice  to  most  solvents,  including  aromatic  hydrocarUins, 
oils,  acids,  alkalies,  and  water,  will  retain  its  flexibility  even  at 
extremely  low  temperatures,  and  will  not  sustain  a  flame 


Opening    of    a    branch    office    in    Los    Angeles    ha-    U-en 
announced  by  Velveray  Corp.,  New  York  City.    Harold  Harris 
is  manager  of  the  new  branch,  where  he  will  introduce,  to  the 
wc-t  coast  area,  the  company's  exclusive  Fuscprint  prcx  • 
plastics  film  printing. 

In  the  Velveray  company's  process,  which  is  said  to  employ 
an  entirely  new  technique,  printed  plastics  films  are  produced  hy 
means  of  specially  developed  equipment  which  fuses  the  design 
into  the  film,  utilizing  a  combination  of  inks  and  suitable  solvent-. 
The  design  thus  applied  will  neither  crack  nor  wear  off,  having 
become  an  integral  part  of  the  film.  Temporary  location  of  the 
Los  Angeles  establishment  was  announced  as  609  S.  (Irand  St. 


A  change  of  name  has  been  announced  for  Unexcelled  Mfg. 
Co.,  Inc.,  hy  Wildcy  C.  Kickerson.  chairman  of  the  board  of 
directors.  The  company  is  now  to  IK-  known  as  Cncxcelled 
Chemical  Corp.,  the  change  having  been  made  in  order  to  de- 
scrilie  more  accurately  it-  enlarged  scope  of  activities,  which 
now  include  the  manufacture  of  paint,  varnish,  plastic-,  indus- 
trial finishes,  and  various  other  products.  C.  Russell  Maci  • 
has  heen  elected  president  of  the  corporation,  succeeding  Thumas 
Jardine  who  has  Ix-come  vice  chairman  of  the  board. 


A  sales  and  business  otVice  has  In-en  opened  at   1700  Walnut 
St.,  Philadelphia,  by  Hcydcn  Chemical  Corp.,  N'.   Y. 


Recent  announcement  ha-  been  made  of  the  resignation  of 
Ku-sell  A  Wallace  from  the  Celane-e  Corp.  of  America,  whert 
lie  wa-  formerly  in  charge  of  pla-tic-  and  chemical  c\i>ort-.  to 
In-come  a  partner  in  the  firm  of  Dussi-Wallace  \  Co.  at  <><>  K. 
42nd  St.,  New  York  City.  The  newly-formed  partnership  i-  to 
act  a-  the  American  branch  "t"  several  large  enterpri-es  in  -outh- 
ca-tcrn  Europe,  the  Near  East  and  Latin  America,  representing 
plastic-,  chemical  and  electrical  line-.  The  announcement  add- 
that  Mr.  Wallace  will  organi/c  the  pla-tic-  department  of  the 
new  company,  covering  the  full  range  of  |>la-tic-  material-,  mold- 
ing and  fabricating  equipment. 


Convenience   and   efficiency   are   cmlxidicd   in   an   umi-nal 
method  of  obtaining   full   and  detailed   information   from   manu- 
facturer-   who   are   contemplating    n-e   of    pla-tii-    m.iteri.il-    in 
their   rc-|x-ctivc   products.      I— ucd  by   Creative   Plastic-   Corp. 
Mrooklyn,   N.   Y.,  this  is  designated  as  a  "quiz  sheet"  anil  c«m- 
n  qiie-tiotis.  couched  in  nun  -technical  term-      Ity  its 
n-e.    the    manufacturer    can    -upply    enough    information    on    his 
product    in   enable    tin-    I  name    (  'urination's   eiigineit-    to   de 
i  iile   whether  or  imt    pla-tii  -    will   !»•  adaptable  to  the  nuimlac 
Hirer's  requirement-  and  if  -o.  which  pla-lic-  -hoiild  In-  u-ed 


Formation  of  an  e\|«irt  division,  to  Ix-  |i«-atcd  at  11  \\e-t 
4Jnd  St.  New  Y..rk  I  tty.  h.i-  IK-I-H  announced  by  the  <.  S 
Hlodgctt  (o.  Inc.  Hurlingtim,  Yt  .  maker  nf  various  typei  of 

The    new    divi-ion    will    Ix-    under    the    managcm- 
Richard  Ki-cmiiaiin  l".x|>«>t< 


A  new  firm  for  the  -ale  of  special  equipment  in 

nig   ha-   recentl  .ini/itl  by   W.    II     David-' 


I'L.iXTH ' 


OCTOKKK   l«il« 


H.  K.  Serncr.  The  firm  plans  to  specialize  in  the  fields  of 
solvent  extraction,  agitation,  solvent  recovery,  mixing,  distilla- 
tion, special  heat  exchange  process  and  special  furnace  design. 
Offices  are  located  in  the  Commercial  Trust  Bldg.,  Philadelphia, 
and  at  342  Madison  Ave.,  New  York  City. 


A  new  plastics  mold  polishing  service  is  being  offered  by 
Acme  Scientific  Co.,  Chicago,  which  advises  that  the  new  method 
is  based  primarily  on  lapping  and  optical  polishing.  Said  to 
provide  a  uniform  finish  even  into  deep  recesses  and  close  to 
corners,  use  of  these  mechanical  processes  is  described  as  assur- 
ing improvement  and  faster  delivery  at  no  increased  cost. 


Preliminary  data  has  recently  been  released  on  a  new 
thermosetting  silicone  resin  developed  by  Dow  Corning  Corp., 
for  use  in  formulating  exceptionally  heat-and-moisture-resistant 
paints  having  a  hard,  mar-resistant  surface.  Designated  as  DC 
804.  the  new  product  is  especially  indicated  by  its  makers  for  use 
in  formulating  white  finishes  having  properties  between  those  of 
ceramic  coatings  and  ordinary  organic  paints. 


Formation  of  Plastomic  Products  Co..  Inc.,  with  plant  and 
sales  offices  at  25-11  30th  Ave.,  Astoria,  N.Y.,  has  been  an- 
nounced. A.  H.  Menkin,  formerly  chief  engineer  of  the  chemical 
and  plastic?  division,  Century  Lighting,  Inc.,  is  president  of  the 
new  corporation,  which  plans  manufacture  and  distribution  of 
plastics  toys,  hobbycraft,  and  novelty  items.  Other  officers  elected 
include  R.  J.  Taplinger,  treasurer,  and  H.  L.  Edsall,  secretary. 


Plastics'  use  in  umbrellas  is  finding  increasing  favor,  and  in 
overcoming  rod  breakages,  several  designers  have  used  ex- 
tremely resilient  ribbed  plastics  bars,  having  found  that  it  is 
possible  to  produce  plastics  ribs  which  are  more  flexible  than 
the  metal  ribs,  and  are  applicable  to  the  storm-type  of  reversible 
umbrella.  Breakage  was  kept  at  a  minimum  through  flexibility 
of  these  new  ribs. 


A  series  of  informative  articles  on  plastics  is  being  published 
by  The  J.  L.  Hudson  Co.,  Detroit  department  store,  in  its  house 
organ,  The  lludsonian.  Feeling  that  with  new  plastics  and  plas- 
tio  textiles  appearing  so  rapidly  on  the  market,  it  is  sometimes 
difficult  for  sales  personnel  in  shops  to  keep  fully  informed  as  to 
the  quality,  characteristics  and  potentialities  of  the  new  mer- 
chandise, the  company  has  adopted  this  method  of  keeping  its 
personnel  as  up  to  date  as  possible  on  new  developments  in 
plastics. 

Beginning  in  the  July  issue  of  the  house  organ  with  a  discus- 
sion of  vinyl  plastics,  the  series  is,  according  to  announcement, 
scheduled  to  continue  with  articles  on  other  plastics  as  well  as 
natural  fabrics,  Sanforising,  synthetic  rubber,  glass  fibre  fabrics, 
and  weaves.  Kach  item  is  to  be  discussed  from  the  standpoint  of 
history  of  its  development,  its  chemical  components,  properties, 
current  and  potential  uses. 


Recent  report  from  Libbey-Owens-Ford  Glass  Co.  advises 
that  the  company's  production  of  plate  glass,  window  glass,  and 
plastics  has  been  at  near-capacity  levels  during  the  second 
quarter  of  1946.  despite  current  shortages  of  raw  materials  and 
supplies. 


An  indication  of  the  "plastics  consciousness"  of  the  American 
public  is  felt  by  the  B.  F.  Goodrich  Co.  to  be  evidenced  in  the 
unexpectedly  heavy  demand  for  a  new  type  of  clothesline  recently 
introduced  by  that  company.  A  departure  from  the  familiar 
woveii^  cotton  line,  the  new  product  has  a  jacket  of  white,  Good- 
rich Koroscttl  around  a  high-tenacity  rayon  cord  core,  the  com- 
bination providing  a  number  of  advantageous  qualities  to  the  user. 

A  recently-formed  company,  Hadley.  Ryder  &  Pederson, 
design  consultants,  with  offices  to  be  located  in  Hartford,  Conn., 
has  been  announced.    Its  principals  are  Donald  L.  Hadley,  form- 
:rly  design  consultant  for  Westinghouse  Electric  Corp.,  Carleton 
Ryder  and  Nicholas  F.  Pederson,  previously  co-ordinator  of 
apparatus  design  and  technical  supervisor,  respectively,  of  the 
General  Electric  Co.,  who  resigned  from  those  positions  in  June 
I  this  year  for  the  purpose  of  forming  their  present  organization. 


An  important 

event  in  the 

field   of 

plastics 


EXPERIMENTAL  PLASTICS 
and  SYNTHETIC  RESINS 

By  G.  F.  D'ALELIO 

formerly  Vice-President  in  Charge  of  Research, 
Pro-phy-lactic  Brush  Company 

No  comparable  book  exists  for  chemists  and 
chemical  engineers  in  the  field  of  plastics.  It 
is  completely  modern,  providing  invaluable 
data  nowhere  else  available  in  a  single  volume. 
EXPERIMENTAL  PLASTICS  AND  SYN- 
THETIC RESINS  contains  almost  100  experi- 
ments and  27  test  methods  for  plastics.  Prac- 
tically all  of  the  well-known  resins  and  plas- 
tics which  can  be  prepared  readily,  even  in  a 
small  laboratory,  have  been  included. 
EXPERIMENTAL  PLASTICS  AND  SYN- 
THETIC RESINS  is  not  intended  as  a  book 
of  instructions  on  manufacturing  procedures. 
Rather,  it  aims  to  demonstrate  the  chemical 
reactions  used  in  the  preparation  of  plastics 
materials.  It  gives  the  essential  principles  and 
chemical,  laws  governing  the  important  plas- 
tics of  today.  Many  of  the  results  obtained  in 
these  experiments  can  be  used  directly  in  indus- 
trial production.  Others  need  only  further 
study  for  development  into  industrial  products. 
Dr.  D'Alelio's  reputation  as  a  brilliant  scien- 
tist in  the  plastics  field  fully  guarantees  to 
industry  and  the  chemical  profession  the 
character  and  reliability  of  this  book. 
1946  186  Pages  $3.00 

ON  APPROVAL  COUPON 
JOHN  WILEY  &  SONS.  INC. 

440  Fourth  Ave..  New  York  16.  N.  Y. 

Please  send  me  a  copy  of  D'Alelio's  EXPERIMENTAL 
PLASTICS  AND  SYNTHETIC  RESINS  on  ten  days'  ap- 
proval. If  I  desire  to  keep  the  book,  I  will  remit  $3.00 
plus  postage;  otherwise  I  will  return  the  book  postpaid. 

P-10-46 
Name     . 


Address 

City    

Employed   By 


State 


(Approval  offer  not  valid  outs idt  I'.  .S.  utnl  C.n 


OCTOBER  1946 


I'LASTICS 


89 


WE  ore  now  granting  license 
and  furnishing  equipment  for 
making  this  sensational  new 
folded  plastic  box. 

Protection,  reuse  and  display 
combine  in  these  rigid  boxes 
that  are  made  from  cellulose 
acetate  or  vinylite  and  which 
require  no  cement  or  solvent 
to  hold  them  together. 

THE  BOX  THAT'S  NEVER  THROWN  AWAY 

.1011  \    II.   OXLEY  CO. 

Maiinla€-iiir.-r  A    l»e->l|(ner 
WATKRTOWX 


PERFECT  PLASTIC  PRODUCTS 
NEED 

PERFECT  MOLDS 


"Salco  Master"  Service  with  its  fine  engineer- 
ing department,  comprehensive  shop  equip- 
ment, and  skilled  die  makers,  hand  and  panto- 
graph engravers  is  in  position  to  turn  out  the 

PERFECT  MOLD 
whether  for  precision  or  ornamental  plastics 

ior 

Injection  Molds — Hobs  and  Hobbings 

Pantograph  Engraving  in  Molds 

Steel  Type  and  Dies  for 

Stamping  Plastics 


SCHOOER  &  LOMBARD  STAMP  &  DIE  CO.,  INC. 

112-111    LAFAYETTE   ST..   N.w    York    13.   N.   Y. 


Harry  H.  Purvis,  general  manager  of  Chicopee  Mfg.  Corp.'s 
new  J.umitf  plant,  Cornelia,  Ga.,  reports  transfer  of  the  following 
personnel  from  the  company's  Gainesville  establishment,  as  mem- 
bers of  the  executive  staff  :  J.  L.  Hall,  plant  manager  ;  Charles 
Rudolph,  head  of  research  and  development;  W.  T.  Torgeson, 
office  manager. 

*     »     * 

Mil-hard  S.  Morse,  president  of  National  Research  Corp..  Bo* 
tun.  has  announced  that  Hartley  Rowe  has  been  elected  to  the 
board  of  directors  of  that  organization.  Mr.  Rowe,  who  i-  vice 
president  and  chief  engineer  of  United  Fruit  Co.  of  Bo«1 
also  a  director  of  Reed- Prentice  Corp.,  and  of  Scott  8.  \ViIli:ims, 
Inc. 

»     »     » 

Wallace  L.  Nahin  has  been  appointed  manager  of  the  in- 
dustrial plastics  division  of  the  Clarvan  Corp.,  Milwaukee.  U'is.. 
where  he  will  develop  and  promote  new  industrial  uses  of  flexible 
plastics  tilms  and  rigid  plastics  sheets,  involving  the  company's 
own  processes  of  electronic  welding,  die  cutting,  molding,  etc. 


W.  L.  Nahin 


P.  M.  Dinkins 


W.  Sandberg 


P.  M.  Dinkins  has  been  made  president  and  a  director  of  Jef- 
ferson Chemical  Co.,  Inc.,  an  organization  formed  in  November 
1944  by  American  Cyanamid  Co.  and  The  Texas  Co.  for  produc-  ! 
tion  of  chemicals  from  petroleum  and  petroleum  gases  Its  hrst 
plant,  now  under  construction  at  Port  Nechcs,  Tex.,  is  to  pro- 
duce intermediate  chemicals  for  use  in  the  plastics,  synthetic 
nihhi-r.  textile  and  other  industries. 

*  *     • 

J.   K.   Harm's,  president  of  Barnes  &  Keinecke.   Inc..  I'l 
has  made  announcement  of  the  appointment  of  William  Sand- 
berg  to  the  (Mission  iif  advertising  manager  of  that  organization 

*  »     * 

John  O.  Forster  has  tx-comc  chief  engineer  of  Aircraft  "• 
Products  I'd.  Inc..  l-ong   Island  City.  N.  V. 

«     »     • 

A  division  which  will  specialize  in  tlic  development  oi  hydraulic 
equipment,  with  W.  H.   Marsh  as   general   manager,   ha- 
estalilishcil  by  the  Rockwell  Mfg.  Co.  Pittsburgh. 
«     •     • 

J.  W.   Barnett   h.is   resigned   the   presidency   of    Harnctt.    Inc, 
Atlanta,  da.,  to  become  plastics  consultant.  tnaniifacti:- 
sentativc   ami    -airs   engineer  for   a   croup  of   companies    r 
Southern  -• 

*  •     • 

K.  -tin  nirnt  of   Everett  G.  Ackart.  chief  cnginin    • 
iliiPont  <le  Nmioiirs  &  Co.,  and  appointment  of  Granville  M. 
Read    as    his    successor,    has    U-cn    announced    l>\    the    I  >n 


l-'oiir  newly  rnatrd   s.ili  •«   |H.S(S  .md   n-.n  i.mm  iwnt   •>! 
tin     lompaiiy's    s;iles    .irras    m    New    Kngland    and    two    in    the 
South,  have  IHTII  announced  by  The  Mathievm    \lkali   \\.nks. 
New    York    I  itv      In   one   of   the   southern  areas.   Harold   R. 
Dinge«  has  U-i-n  namrd  disirnt   sales  manager,  headquartering 


r  i.  \  s  T  1 1  * 


OCTOHKR   1 


in  Charlotte,  N.  C.  He  will  be  assisted  by  O.  J.  Theobald, 
Jr  Company  sales  activities  in  parts  of  Tennessee,  Alabama 
and  Georgia  will  be  in  charge  of  Fred  O.  Tilson,  appointed 
district  sales  manager  for  that  area,  with  headquarters  in  Chat- 
tanooga. In  Providence,  William  H.  Eastburn  has  been  ap- 
pointed district  sales  manager  for  the  company's  newly  denned 
New  England  sales  area. 

*  *     * 

Richard  F.  Muller  has  been  named  manager  of  the  New 
Orleans  district  office  of  Allis-Chalmers  Mfg.  Co.,  succeeding 

F.  W.  Stevens  who  has  been  appointed  special  representative 
for  the  company  in  the  New  Orleans  office. 

*  *     * 

John  R.  Brown,  Jr.,  has  become  director  of  chemical  research 
of  the  Proton  laboratory,  Pro-phy-lac-tic  Brush  Co.,  Florence, 
Mass.  Mr.  Brown,  whose  background  and  experience  in  the 
chemistry,  plastics  and  synthetic  rubber  fields  have  been  exten- 
sive, was  previously  instructor  of  chemical  engineering  at  Massa- 
chusetts Institute  of  Technology. 

*  *     * 

Robert  E.  Segerdell  has  been  appointed  office  manager  of 
the  San  Francisco  office  of  Hercules  Powder  Co.  Thomas  E. 
Brown  has  become  assistant  superintendent  of  the  company's 
plant  at  Bacchus,  Utah. 

*  *    * 

Paul  C.  Grimes,  formerly  New  England  representative  for 

G.  S.  Blodgett  Co.,  Inc.,  Burlington,  Vt.,  which  makes  a  variety 
of  ovens,  has  been  named  midwestern  representative  for  the  com- 
pany, and  will  have  his  headquarters  in  Chicago. 

*  *     * 

M.  L.  Macht,  technical  service  representative  of  the  plastics 
department,  E.  I.  du  Pont  de  Nemours  &  Co.,  has  been  elected 
vice  chairman  of  Committee  D-20  of  the  American  Society  for 
Testing  Materials,  which  handles  development  of  tests  and  speci- 
fications for  plastics.  He  has  been  associated  with  Du  Font's 
plastics  department  since  1925. 

*  *     * 

Pennsylvania  Salt  Mfg.  Co.  has  announced  recent  personnel 
additions,  as  follows :  To  its  research  and  development  depart- 
ment, I.  R.  Mockrin  and  W.  A.  Blum;  and  W.  A.  Millsaps, 
A.  J.  Baldi,  and  Miss  A.  L.  Nicholson  to  the  technical  staff 
at  the  company's  Whitemarsh  research  laboratories. 

*  *     * 

Emil  G.  Holmberg  has  been  appointed  consulting  metallurgist 
for  Alloy  Steel  Products  Co.,  Linden,  N.  J. 

*  *     * 

Announcement  has  been  received  of  the  death,  on  August  10, 
of  Milton  Rowley,  Sr.,  president  of  Keystone  Brass  Works. 

*  *     * 

Dr.  L.  B.  Sebrell,  director  of  research  for  the  Goodyear  Tire 
&  Rubber  Co.,  has  announced  that  Warren  W.  Burr  will  head 
the  section  handling  development  of  the  company's  protective 
coatings  and  Plinlite  resins. 

*  *     * 

Announcement  has  been  received  of  the  resignation  of  Law- 
rence M.  Brown  from  the  vice-presidency  of  Electronic  Corp. 
of  America  and  of  E.C.A.  International  Corp.  to  organize  the 
Rich-Marc  Mfg.  Co.,  Inc.,  which  will  manufacture  plastics  and 
metal  radio  components  and  electronic  equipment.  Offices  and 
factory  of  the  new  company  are  to  be  at  42  West  28th  St.,  New 
York  City. 

*  *    * 

J.  R.  Thompson,  who  has  been  associated  with  the  B.  F. 
Goodrich  Co.  since  1930,  has  been  named  Denver,  Col.  district 
manager  of  the  company's  industrial  products  sales  division,  it  is 
announced  by  E.  F.  Tomlinson,  division  general  manager.  In  this 
post,  Mr.  Thompson  succeeds  John  Gulledge  who  has  been 
acting  district  manager  in  Denver  but  is  being  assigned  other 
duties  in  the  industrial  products  division. 

*  *     * 

Walter  B.  Briggs,  formerly  manager  of  the  power  trans- 
mission division  of  Ideal  Industries,  Inc.,  has  been  appointed 
general  manager  of  the  power  transmission  division,  Lovejoy 
Flexible  Coupling  Co.,  Chicago. 


-to Hold  Plastic 
Parts  in  Secure 
Position  in  Jigs 
and  fixtures 


The  illustration  above  \ 
shows  how  eight  No.  250  \ 
De-Sta-Co  Clamps  hold 
work  in  position  in  vacuum 
fixture  while  clear  Plexiglass 
is  formed  into  navigator's 
astrodome  for  aircraft.  One 
of  many  applications  for 
De-Sta-Co  in  the  working 
of  plastics,  plywood  and 
other  materials. 

Whether  it's  forming,  sawing, 
grinding,  gluing,  milling — any 
operation  where  accuracy  is 
vital— De-Sta-Co  Clamps  will 
promote  time-saving  efficiency 
in  production  or  assembly. 
Greatly  simplify  the  building 
of  jigs  and  fixtures. 

Holding  pressure  is  positive, 
uniform,  gentle.  Automati- 
cally maintained  .  .  .  instantly 
released. 

Catalog  No.  45describes  com- 
plete line  of  De-Sta-Co  Clamps 
—  suggests  many  time-saving 
uses.  Write  for  your  copy. 


MODEL  605 


2O5-A 


=  382 


OCTOBER  1946 


PLASTICS 


91 


OPEN 

TIME 

AVAILABLE 


PLASTIC    MOLDS 

PLASTIC  SERVICE  ENGINEERING 

2567  WEST  GRAND  BLVD. 
DETROIT  8,  MICH.  DEPT.  21  Tyler  7-2055 


Caty 

COLOR 
YOUR   PLASTICS! 

REZ-N-DYE* 

(COLD  OIF  DYE) 

NO  HEAT  I—  NO  MIXING! 

Fast  Color*  all  plastics  in  a  matter  of  seconds  or  min- 
utes depending  on  depth  of  shade  desired.  Simply 
immerse  in  dye.  rinse  in  water,  wipe  dry.  Polishing 
does  not  afiect  color. 

21  Different  Colors  $*2  Gallon  F.  0.  B.  Factory 

Mottling  Compound  fcr  TORTOISE  SHELL  Efftet  $3.00  Of 

SCHWARTZ  CHEMICAL  CO. 


326-328  Wttl  70th  Str.»t. 


N.w  York  23,  N.  Y. 

•  If.d.    Murk 


"RCZ-N-KLECN"  INSTANTLY  removes  all  foreign  sub- 
•tancw  bora  Luctt*  and  Pl»xigla« 

"REZ-N-OLUE"  New!  lmpro**dt  Water  White.  P.I 
l*ct  tot  einMaling  most  everything 
to  plastic*. 


.Annual  Meeting  of  New  England  Section,  SPI 

The  Xcw  Kngland  Section  of  the  Society  of  the  Plastic-  In- 
dustry, Inc.,  plans  to  hold  its  annual  meeting  <>n  October  17  and 
IS  .it  K(|iiinox  House.  Maiu-liester.  N't.  The  program  include-  a 
series  of  ti-clinical  papers  especially  prepared  for  the  com. 
which  are  to  be  presented  in  morning  sessions,  with  afternoons 
held  open  for  sports  and  Green  Mountain  tour*.  \V.  1!  Wallace, 
Mack  Molding  Co.,  Arlington.  \'t..  is  conference  chairman. 

Scheduled  s|>cakers.  and  tin-  topics  which  they  have   sel 
are:     Frank    H.    Carman,   general    manager    Plastic    Mali  rials 
Manufacturers   Association.   Inc..   "Review   of   Plastic   Ma- 
Supply  Outlook ;"  James  Bailey,  vice  president  and  director  of 
research.  Plax  Corp..  "Kxtruding  Acrylics:"  Uicster  M    RoMiins, 
vice  president.   Aridye  Corp.,  division   of   Interchemical   i  .irp., 
"Printing  on   Vinyl  Film:"  C.  A.   I.ydecker.  president.   I' 
Kc.ll  Leaf  Ci>..  Inc..  "Roll  Leaf  Stampings  on  Plastics" 


Jo/nV  Golf  Outing 

>l.onsored  jointly  by  the  metropolitan  chapters  of  the  ."• 
of  the   Plastics   Industry  and  the  Society  of  Plastics   Fngineen, 
a   golf  outing   was   held  on   September   10  at   the   Oak    Ridge 
Country  Club.  Purchase,  X.  V.    Jack  Lein  was  chairman  of  the 
arrangements  committee. 


Cleveland  Sections  of  SPE,  ASTE,  to  Meet 

The  first  Fall.  I'M'),  meeting;  of  the  Cleveland  section  of  the 
Society  of   Plastics   Kngineers  was  announced  for  Septem! 
to  IK'  at  the  Cleveland  Club,  preceded  by  a  dinner. 

Among  the  speakers  scheduled  for  the  meeting  were  A  K. 
Morse,  midwt'stern  representative  of  Reed- Prentice  Corp..  on  the 
topic  of  "Injection  Equipment";  (iregg  Langemeyer,  superintendj 
em.  The  Pioneer  Mold  Co.  -.(leaking  on  "Recent  Trends  in  Mold 
Design";  and  "Hill"  Johnson,  of  Plastics  Knginccring.  Inc., 
whose  subject  was  "Metluxls  in  the  Mold  Shop" 

Following  the  regular  meeting,  a  meeting  of  all  of  the  com- 
mittees of  the  Section  was  scheduled,  for  presentation  ,,f  plans 
for  the  entire  forthcoming  year 

(  ictolHT  IS  has  Ix-en  scheduled  as  the  date  of  the  second  Fall 
meeting,  at  Allerton   Hotel,   to  lx'  held   jointly  with  the  i 
land  chapter  of  the  American  Society  of  Tool  F.ngin- 
s|>eakers  have  Ix-cn  announced  as  Cordon  It.  Thaycr.  pla-tics  re- 
search engineer.  Dow  Chemical  Co.  and  Russell  Ilradshaw.  plas- 
tic- engineer,  of  the  same  company. 


Plastics  Club  of  U.  S.  Meets 

The  first  fall  meeting  of  The  Plastics  Club  of  the  United  State! 
was  held  on  Septemlx-r  10  at  the  Hotel  Pennsylvania.  Xcw  York 
l  ity.  Aims  and  future  programs  of  the  club  were  discussed. 


St.  Louis  Chapter  of  SPE 

A  dinner  meeting  at  the  DeSoto  Hotel,  on  Scptcn.' 
p.irt    of   the   opening   program   of   fall   and   winter   activir 
ipter  of  the  Society  of  Plastics  l-.ngr 

Scheduled  guest   s|x-aker   was    I     C    Ka/imier.   Amos    Molded 
PlaMiis   (  ii..    Edinburgh,    Iml.   whose   topic    wa»   annoui. 
"The  Ini|Kirtance  of  Kngineering  and  Selling." 


ASME  Fall  Meeting 

The  I'M' i  fall  meeting  of  the  Amen  Mechanical 

Fnginccrs  was  announced  for  September  A'.  <  tctolx-r  1.  J  and  .', 
at    the    Hotel    Statler.    llo-lon.      A    well-rounded    program    was 
scheduled   for   the    lour   days,   with    -.nine   J<l   techin. 
spoilsornl  li\    prolessi.inal  divisions  of  th.  !   to  a 

comprehensive  range  of  pertinent  topics 


92 


s 


OCTOHKK   n 


Change  of  Exhibit  Half  for  SPE  Exposition 

The  Society  of  Plastics  Engineers  has  announced  that  the 
Third  Annual  National  Meeting  and  Exhibit  of  that  organiza- 
tion, scheduled  for  January  28  through  February  2,  1947,  in 
Chicago,  will  be  held  at  Drill  Hall,  Navy  Pier,  instead  of  at  the 
Coliseum,  as  originally  planned.  The  SPE  Convention,  which 
will  take  place  concurrently  with  the  exposition,  is  to  be  at  the 
Congress  Hotel,  Chicago,  according  to  announcement. 

A  few  revisions  in  listing  of  committee  personnel  have  also 
been  announced ;  Robert  G.  Chollar,  National  Cash  Register  Co., 
Dayton,  is  vice  chairman  of  the  meetings  committee,  serving 
with  chairman  W.  L.  Hess ;  Harry  J.  McGowan,  Bakelite  Corp., 
Detroit,  is  chairman  of  the  budget  and  finance  committee ;  and 
Michael  H.  Froelich,  plastics  magazine,  Chicago,  is  vice  chair- 
man of  the  publicity  committee,  of  which  J.  A.  Boyajian  is  the 
chairman;  L.  H.  Amrine  is  chairman,  registration  committee. 


Packaging  Machinery  Executives  Meet 

The  fourteenth  annual  meeting  of  the  Packaging  Machinery 
Mfrs.  Institute  was  announced  by  Frank  B.  Fairbanks,  president 
of  the  organization,  for  September  29  and  October  1  at  the 
Shawnee  Country  Club,  Shawnee-on-Delaware,  Pa.  Program 
and  arrangements  were  in  charge  of  George  W.  von  Hofe,  presi- 
dent of  the  New  Jersey  Machine  Corp.,  assisted  by  John  P. 
Corley,  vice  president  of  Miller  Wrapping  &  Sealing  Machine 
Co.,  Chicago.  Oscar  W.  Wikstrom,  president  of  U.  S.  Auto- 
matic Box  Machinery  Co..  Boston,  headed  the  sports  committee. 


ASTE  Convention 

The  semi-annual  national  convention  of  the  American  Society 
of  Tool  Engineers  will  be  held  at  the  William  Perm  Hotel. 
Pittsburgh,  October  10  to  12.  An  extensive  and  carefully- 
planned  program  features  technical  sessions,  meetings,  and  a 
number  of  tours  through  modern  industrial  plants. 


Schedule  of  4STM  Fail  Meetings 

Various  committee  and  district  meetings,  and  technical  session-. 
scheduled  for  the  Fall  of  1946  by  the  American  Society  for  Test- 
ins;  Materials,  have  been  announced.  In  addition  to  the  meeting 
of  Committee  D-3  on  gaseous  fuels,  to  be  held  in  Atlantic  City 
on  October  7,  there  is  to  be  a  four-day  series  of  committee  meet- 
ings held  there,  at  the  Chalfonte-Haddon  Hall,  from  October  14 
to  17,  which  includes  Committee  D-20  on  plastics,  October  14,  15 ; 
Committee  D-14  on  adhesives,  October  IS,  16;  and  Committee 
D-9  on  electrical  insulating  materials,  October  16,  17. 

A  featured  address  to  be  given  during  the  four-day  series  is 
one  by  Dr.  W.  O.  Baker,  Bell  Telephone  Laboratories,  Inc., 
scheduled  for  October  15.  Dr.  Baker's  topic  has  been  announced 
as  "Cohesion,  Adhesion,  and  Structure  of  Polymers,"  which  will 
cover  results  of  extensive  X-ray  di  (Traction  studies  on  plastics. 

Committee  K-3  on  chemical  analysis  is  to  meet  at  Washington, 
D.  C.  on  October  IS;  Committee  D-13  on  textile  materials,  at 
the  Park  Centra!  Hotel,  New  York  City,  October  IS,  17  and  18; 
Committee  B-4  on  electrical  heating  and  resistance  alloys,  at  the 
Chalfonte-Haddon  Hall,  Atlantic  City,  October  30,  31  and 
November  I. 

The  Southern  California  district  meeting  of  the  organization 
is  planned  for  October  29,  in  Los  Angeles;  and  the  Detroit 
district  meeting  in  Detroit  on  November  13. 


WE  ARE  PRINCIPALS  ACTING   IN  OUR   OWN   BEHALF   WILLING    1O 


PAY   YOU 

IMMEDIATE 


CASH 


For  ASSETS  or  CAPITAL  STOCK  of  ... 

•  INDUSTRIAL  PLANTS 

•  MFG.  DIVISIONS  or  UNITS 

All  transactions  held  in  strictest  confidence.  Personnel 
retained  wherever  possible 

ADDRESS:  Box  1241  147  W.  42  St.,  New  York  18,  N.  Y. 


IN  GOLD,  SILVER  OR  COLORS 


PLASTIX 


A  NEW  PENCIL  for  a   NEW   INDUSTRY 

Ordinary  pencils  won't  mark  .  .  .  ink  runs  and 
labels  fall  off  the  average  smooth,  glossy  plastic 
surface.  Blaisdell  PLASTIX  Pencils  were  made 
for  the  purpose.  Their  marks  are  brilliant,  legible, 
waterproof  and  permanent,  yet  easy  to  remove 
with  a  damp  cloth.  Try  one  and  prove  it  yourself. 

Made  in  7  colors: 

1064-T  White  1068-T  Blue  1070-T  Yellow 

1065-T  Crimson  Red  1069-T  Red  1071-T  Green 

1073-T  Black 
Order  from  your  deo/er  or —    *e«».  u.  s.  p»t.  Off. 

Mail  this  caution  for  FREE  SAMPLE 

Ji/aisde/7'  PENCIL  COMPANY 

141  Berkley  St.,  Philadelphia  44,  Pa.,  Dept.  PL- 3 
Send  me  sample  of  No 


OCTOBER  1946 


PLASTICS 


93 


IF  YOU  WANT  OUTLETS 
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or   General    Merchandising   and    Novelties 

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{W*  UUI  Cmrry  Our  <>:~    -Ir.ounc.  if  rf.r.iigry) 

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AfSOCIATIS 
FACTORY    RIPMSENTATIVIS    AND    MSTRIIUTOKS 

•J  E.  ADAMS  ST.  CHICAGO  3,  ILL 


FOR  SALE 

3  Triplex  Hydraulic  Pumps  with  7'/2  h.p.  Gen- 
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pounds.    Delivery  15  gal.  low  pressure,  5  gal. 
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GEORGE  STEINER  COMPANY 
1220  W.  Lake  Street  Chicago,  Illinois 

Haymarlcet  6027 


General  Trucking  to  All  Part*  of  Greater  New  York  and 
Vicinity.  Full  or  Part  Loads  Solicited.  General  Knowledge 
in  the  Handling  of  All  Plastics  Materials.  Fully  Insured. 

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EXpress   1000 

DISIONMS    PLASTIC   MOLDS    BUILDERS 

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FOR  SALE- 


N*w  &    Uied    Hydraulic    Equipment.      Consultant.    Engineering 
•  nd    Repair    Service       Send    us   your   inquiries, 

AARON   MACHINERY  CO. 

41  Cro.br  St..  N.  T.  C.    U  I.I.  Canal  6-0421 


ROUTER  BITS— FORM  CUTTERS  and 
MACHINES  for  HIGH  SPEED  CON- 
TOUR and  STRAIGHT  CUTTING  PLASTICS 

SfnJ  lor  Ctlflog  No.  41 

EKSTROM,  CARLSON  &  CO. 

Mil   Railroad   A»».  ROCKFORO.  ILL. 


PLASTIC    CEMENT 

Fait   Drying,   vastly    applied,    no   pr«»»r«    reqyired 

For  mounting  pUitic  !t»ms  on  display  cards. 

end  plastic  aitambty. 

Avulthl*    immodnttly    in    DA*   a*O*    fi»»    gtllo*    CeVIS. 

TEXON     INDUSTRIAL     CORP.L^  ' 


r 


Ladies  Apparel  Adopts  Plastics 

(Continued  from  page  58) 


example  of  what  can  be  done.  Large  arm  openings,  a  deep 
"vee"  back,  and  an  open  bodice  permit  air  circulation.  The 
problem  of  inserting  buttonholes  has  been  obviated  by  tin- 
use  of  ties  (elastic  drawstrings  served  the  same  purpose 
for  the  other  garment  exhibited).  The  film  was  supplied 
in  an  overall  pattern  of  white  figures  on  a  transparent 
background.  In  discussing  the  dress,  spectators  remarked 
its  possible  use  at  the  beach  or  swimming  pool,  for  wear 
over  a  bathing  suit.  Representing  consumers  and  com- 
mercial buyers,  observers  were  unanimous  in  praising  the 
innovation  as  a  forward  step  and  in  expression  of  hope  that 
it  would  be  followed  up. 

Harold  Gudnason,  vice-president  and  general  manager 
of  Alice  of  California,  feels  that  all-plastics  fabrics  may 
have  great  influence  on  the  future  of  the  garment  industry. 

"Plastics  are  new,  and  the  public  is  greatly  interested," 
he  said.  "They  apparently  offer  a  combination  of  certain 
wearing  and  handling  qualities  impossible  to  attain  with 
other  fabrics — opening  up  new  ranges  of  possibilities  to 
the  fashion  designer.  Meanwhile,  a  great  deal  of  mutual 
development  work  is  necessary.  Perhaps  we  will  find  the 
currently  available  materials  more  satisfactory  as  we  be- 
come more  familiar  with  them.  At  the  same  time,  the 
plastics  industry  should  try  to  understand  our  problems 
and  work  with  us  to  overcome  them.  I  believe  that  the 
results  of  such  cooperation  would  be  exceedingly  worth- 
while— particularly  here  in  California  where  styling  for 
outdoor  living  is  so  important." 


Know  Your  Caseins 

(Continued  from  fni/t'  •*•'  I 


tremely  complicated  systems,  made  up  of  two  or  more  com- 
plexes, and  that  we  do  not  yet  possess  enough  information 
regarding  them  to  be  able  to  predict  or  account  for  their 
behavior  under  all  condition-. 

The  casein  curd,  prepared  by  either  acid  coagulation  m 
by  enzyme  activity,  is  dried  at  not  much  above  room  tem- 
peratures in  order  to  insure  a  light  colored  product,  which, 
in  the  case  of  the  acid  casein-,  "ill  readily  dissolve  in  al- 
kaline water  solution-.  The  granular  product,  with  an 
average  equilibrium  moisture  content  of  8%  to  12%,  is 
ground  through  hammer  mills  and  screened  to  produce  the 
casein  of  commerce. 

The  relative  <|uantitative  |x>sitioii  of  industrial  casein  as  a 
byproduct  of  the  dairy  industry  i<  indicated  by  figures  pub- 
lished in  "Agricultural  Statistics  1944"  of  the  U.S.  Depart- 
ment of  Agriculture.  In  Table  452,  the  total  domestic  milk 
production  in  1'UJ  i-  -houn  to  have  U-en  122,066  million 
pounds  and  in  Table  4M.  that  of  casein.  4J.268.000  pound-. 
This  could  re-ult  from  the  1.54(1  million  jtounds  listed  in  Ta- 
ble 45_'  a-  "All  other  u-e-  and  to  balance,"  but  there  arc 
doubtle-s  i|iiantities  of  -kirn  milk  not  listed  as  such  which  are 
normally  surplus  over  and  alx.ve  all  that  are  Used  for  food 
and  feed  purpose-  and  freijuently  are  wasted.  The  practical 
utilization  of  larger  amount-  of  this  surplus  and  waste  skim 
milk  is  of  considerable  ini|xirtance  to  the  dairy  industry 
and  to  the  farm  economy.  This  has  brrn  recognized  in  the 
I'.  S.  Department  of  Agriculture,  and  a  research  ptoKram 
has  IK-CII  instituted  at  the  Ma-tern  Kcgioiial  Research  Lab- 
oratory directed  to  improvements  in  the  manufacture  and 
utili/ation  of  casein.  Promising  results  in  several  lines  of 
this  investigation  have  already  U-en  rc|x>rted. 

The   casein   plastic-    ( .,j/,;,'i//i    ua-   developed    in   <  Icrinany 


94 


f LAST n  s 


(KTOHKK   19  16 


about  1900  and  is  in  consequence  the  second  plastics  to  have 
been  produced  commercially.  The  development  was  based 
upon  the  fact  that  casein  treated  with  formaldehyde  was 
stabilized  to  a  degree  permitting  the  production  of  solid 
pjeces — such  as  buttons,  combs,  and  ornaments — that  would 
not  craze  or  shatter  spontaneously.  The  process  of  manu- 
facture, as  perfected  after  several  years  of  development,  con- 
sisted in  mixing  rennet  casein,  ground  to  40  to  80  mesh, 
with  water  to  give  a  total  moisture  content  of  about  40% 
and  in  feeding  this  powder  to  worm  extruders,  which  con- 
verted the  powder  to  soft  rods.  These  were  finished  as  rods 
by  immersion  in  about  4%  formaldehyde  solution,  or,  if 
sheets  were  required,  the  soft  rods  were  cut  into  6"  to  10" 
lengths,  laid  out  within  suitable  frames,  and  hot  pressed  in 
multiple  opening  hydraulic  presses,  chilling  under  pressure 
before  removal.  The  sheets  were  then  immersed  in  the  same 
formaldehyde  bath  as  the  rods.  The  material  was  kept  im- 
mersed in  the  formaldehyde  bath  until  the  formaldehyde  had 
penetrated  and  reacted  with  the  casein  completely,  a  matter 
of  weeks  or  months,  depending  upon  the  thickness  of  the 
sheet  and  diameter  of  the  rod.  A  rod  of  an  inch  diameter 
required  about  six  months.  Upon  completion  of  the  "hard- 
ening" as  the  formaldehyde  treatment  was  called,  the  mate- 
rial was  seasoned  or  dried  to  remove  excess  water  and  for- 
maldehyde. To  prevent  surface  hardening,  this  required 
controlled  humidity  conditions,  moderate  temperatures,  and 
time  about  equal  to  that  of  the  hardening  period.  The  sheets 
and  rods  were  then  straightened  (the  seasoning  always 
caused  considerable  warpage)  by  very  careful  pressing  in 
heated  presses,  where  they  were  cooled  while  being  main- 
tained under  pressure.  Then  the  rods  were  '"trapped"  or 
ground  to  uniform  diameter  on  centerless  grinders,  and  tin- 
material  was  ready  for  delivery  to  the  fabricators. 

From  sheets  the  objects  were  cut  with  saws,  tubular  for 
round  pieces,  such  as  buttons,  or  band  or  jig  saws  for 
straight  edge  objects.  The  blanks  were  turned,  if  circular, 
or  milled,  sawed,  ground,  etc.,  to  the  finished  state :  "ashed" 
with  wet  pumice  powder,  on  a  rag  buff  for  large  objects,  in 
tumbling  barrels  for  small,  to  remove  tool  marks  and  sur- 
face blemishes ;  and  polished  on  buff  or  in  the  tumbling 
barrel,  as  with  ashing,  with  tripoli  wax.  The  blanked  out 
sheet  material  and  all  turnings  were  waste,  the  material  be- 
ing non-thermoplastic,  and  this  amounted  to  as  much  as  50% 
at  times.  The  tough,  horny  material,  like  practically  all 
plastics,  is  a  very  poor  conductor  of  heat,  hence  inclined  to 
burn  off  the  sharp  cutting  edges  of  all  tools.  Attempts  to 
process  the  material  in  rod  form  through  automatic  screw 
machines  met  with  universal  failure  for  this  reason. 

Although  Galalith.  lirinold,  X eolith,  and  other  European 
casein  plastics  were  apparently  used  quite  satisfactorily  as 
combs,  piano  keys,  electrical  and  lighting  fixtures,  and  in 
numerous  other  fields,  it  was  found  after  painful  and  costly 
experience  to  be  suitable  in  this  country  for  buttons  and 
small  ornamental  objects  only.  This  may  have  been  due  to 
difference  in  climatic  conditions,  the  sudden  temperature 
and  humidity  changes  in  parts  of  this  country  causing  warp- 
age,  fracture,  and  failure  in  the  material  not  experienced  in 
the  more  uniform  climatic  conditions  of  Europe.  Casein 
plastics  objects  are  beautiful  in  color  and  finish,  being  pro- 
duced in  all  shades,  solid  transculent  or  opaque  colors,  and 
streaked  and  mottled  effects.  They  are  fairly  tough  and 
strong  when  they  contain  about  8%  to  12%  moisture,  but 
become  brittle  whenever  this  is  materially  reduced.  Their 
weakness  is  the  tendency  to  absorb  water,  15%  to  25%  on 
a  24  hour  immersion,  with  an  attendant  lack  of  permanence 
and  stability.  It  will  also  be  noted  that  the  costly  process  of 
manufacture  and  fabrication  would  not  readily  fit  into  the 
modern  plastics  picture. 

This  process  was  materially  improved  about  1928  when  a 
button  manufacturer  joined  a  casein  plastics  plant  directly 


complete 
plastic 
display 
fabrication 


satile 
plastic 
ing  in 
now. 


Printloid  produced  this 
plastic  lipstick  display 
for  a  leading  national 
manufacturer  of  cos- 
metics. It  presented 
unusual  problems  of 
design  and  manufac- 
1  ture.  Utilizing  its  ver- 
fabricating  facilities,  Printloid  devised  a 
product  both  functional  in  use  and  appeal- 
appearance.  Consult  with  our  design  staff 


DEPT.  P 
93  MERCER  STREET.  NEW  YORK  12,  N.  Y. 

at  P    I    a    x    f    i    e  Built' 


Complete  facilities  for  Custom  Molding  all  available 
Plastic  Materials  by  Compression,  Transfer,  High  Speed, 
and  Injection. 

WATERBU'RY     COMPANIES,    INC. 

Formerly    Waterbitry    Button    Co..   Est,    1812 

Dept.   S,  WATERBURY.  CONNECTICUT 


OCTOBER  1946 


I'LASTiCS 


95 


PLASTICS 


PROBLEMS    AND    PROCESSES 
2nd   edition,    by   Mo.sperq.r   t    P.pp.r 

Thr   book  conn  m»lnlj    FABRICATION.    «!*>   otldn   anil   ph»lr»l   rhar- 
•curtolln  of   all    tjpw   of   pUnla.      All    tool.,    r-iuipni-ni    «n.l    .unpiir. 
•ii  mill   en  Illiulratni  ud  described.     Working  *lth  plutln.  wood  and 
•Ma!   explained   and    Illiutratrd.     Kormlni .    si,»i.in.-.    suHu-mc;    MMI-I, 
ln«:    AntrabUU:    DMlau    for    Flaxlri:    llmnct      Uld    Mx-hlnr  Work    I'roli 
IMM   etc.      UODMM.    «X».    W   prodlrni    plain.    l.M    lllu,li»n.,i,.      jr.    .!. 
•Una,   rloth.      TiiU   book    U   nrnhHt    hj    th«-   cia(t%mrn    and    tuanufaclurvr. 
MONEY  BACK  GUARANTEE.     Only...  S3. 50  post  paid. 

MODERN    TECHNICAL    BOOK    CO. 
DEPT.    M   P    L..   55   Wait   42nd   St..    Niw   York    18.    N.    Y. 

rtraat   nod    me    coplr*    rUVSTM  s.    I'llnr.l  i  M  -    AMI    rr:., 

KneloMd  nntl  I O  «irk  D  moon  order  O  ca«h.    Plm*  and  D  C.O.D. 

iplua  frrl. 

NA.Mt.         

AllllKKs.s     

CITY  /..INK  STATE 


ANDREW    C.    KARLSTAD 

INDUSTRIAL  DESIGNER 

COMPLETE    PRODUCT    DESIGN   I   ENGINEERING    SERVICE 


414.  VEKTUHA  CANYON  AVE. 
•HONE— STATE  4-S4« 


SHERMAN  OAKS,  CALIF. 
(A  SUBURB  OF  LOS  ANGELES) 


DUALL  MOLDING  CORP. 

Injection    an4    Compression    Moljers 

T«ys — Novelties 

Ornamentel   Plastic! 

and    Metal   Specieltiet 

Complete   Ted    Room    Facilities 

2*7-271  Wychoff  St.         Brooklyn.  N.  Y.        MAI*  5-182° 


— "KRIEGR-O-DIP"— 

HOT    AND   COLD 

Dyes  tor  All  Types  o(  Plastics 
Menufactu  -ed   By 

KRIEGER   COLOR   &   CHEMICAL  CO. 

Member  ol  the  S.P.I. 

Tel.  Hillside  7361  6531   Santa  Monica  Blvd. 

HOLLYWOOD    38.    CALIF. 


Plastic  Molds  Designed,  Engineered  and 

Built  by  Specialists.     Infection  Molding 

Time  Available. 

WOLF-SCHRAGER   CORPORATION 

1412  Auquitina  Avenue.  Far  Rockaway,  New  York 

Call:  Far  Rockaway  7-1 555 


BUSINESS  OPPORTUNITY 

PLASTICS  PRODUCTION   ENGINEER 

Iw  nfTtjr«-»l  Ilium'  ml  in!  fr*-*!  "with  «ir  without  r;i|'lt;il  III- 
v<-Kttii' nt"  In  m-w  "i-|ii«"iK"  Ar<-.'i"  IIH>II|I|>-C|  plaxtlr*  or- 
Kanlzatlon.  amply  flniincfl.  .\i-i'ln-:ttit  must  be  well 
'I  In  up  in  il.it.  pi  ...In.  t  |. .11  i.  .  hiiniif  >-xi-i-pl  il'-- 
olKnlnic  nii'l  .IT  t  work. 

I'.ox    111-      ,    I'l.istli-...    Is:,   N.    Wiilmnll.   ChlniKn    1.    III. 


i w  ATED 

>PINTEn    J*-^iP 


Topflight  Tool  Co. 


PLASTIC  MACHINERY 

£.//  CA-6  2500 


nMTK)  IA«  DIVD1ON 

Hum  no.  tow,  rA, 


MOVING 


mi  oio  triuiif " 
KASILOVSKY 


Trvckmon  and  Mailer  liggert 


'RUCKING,  INC. 

1 39  Grand  St..  N.  V.  C. 


to  lii-~  button  factory  anil  a  casein  j>1;istic>  manufacturer  en- 
tered the  button  business.  Tlu--e  two  ^rou]>~  ik-\elu|>eil  the 
tcchni(|in-  i>i  extruding  alum  tanneil  casein  r«xU.  irnni  which 
lmttoii>  in  i--.eiitially  tlu'ir  t'nial  ~lia|K-  are  turned  liy  auto- 
matic screw  machines.  All  turning  are  reworked,  hence 
there  i^  no  waste.  The  buttons  are  immersed  in  formalde- 
hyde baths,  but  are  thin  in  section,  and  the  |>enetratii>n  and 
reaction  require  only  a  few  day-.  1  he  formaldehyde  cured 
buttons  are  then  drilled  in  automatic  drills,  jxilished.  fin- 
ished, sorted,  and  shipped.  By  this  process,  the  cost  of  case- 
in buttons  has  Inren  reduced  to  the  point  where  vegetable 
ivory  buttons  for  suits  and  overcoats  could  not  compete,  and 
the  latter  have  now  been  almost  completely  replaced  by  the 
more  beautiful  casein  plastics  buttons.  |u«t  prior  to  tlv 
war,  nearly  5000  tons  of  casein  plastics  buttons  were  pro- 
duced annually  in  this  country. 

The  war  did  not  help  the  casein  plastics  industry  in  this 
country.  The  price  of  casein,  its  principal  raw  material. 
rose  from  12-15  cents  per  pound  (rennet  casein  normally 
commands  a  little  higher  price  than  acid  caseins,  to  34}4< 
a  pound.  Worse  than  this,  casein  plastics  buttons  failed  to 
meet  the  specifications  of  the  I'.  S.  Army  and  .Navy  and.  in 
consequence,  the  button  manufacturers  were  forced  to  equip 
for  and  to  produce  buttons  of  urea-formaldehyde,  melamine- 
formaldehyde,  or  phenol -formaldehyde  to  receive  intern- 
ment contracts  and  war  priorities.  In  consequence,  produc- 
tion of  casein  plastics  fell  to  a  reported  6.000.1  XX I  ]b  for  l'M4. 
It  is  anticipated  that  recovery  back  to  the  prewar  production 
figure  will  be  difficult,  because  the  casein  plastic*  button 
manufacturers  are  equipped  to  produce  the  molded  syn- 
thetic resin  buttons  now  and.  unless  the  casein  button  offers 
greater  economies,  increased  business,  or  some  other  strong 
attraction,  much  of  the  former  civilian  trade  will  be  filled 
by  the  resin  buttons.  The  development  of  an  improved 
plastics,  which  could  be  molded  and  would  IK-  economically 
practical,  from  casein  would  change  this  picture  materially. 
Research  directed  towards  improvement  of  water  resistance 
and  of  plastics  How  is  under  way  at  the  present  time  in  Ixith 
<  lovernment  and  private  laboratories. 

The  British  casein  plastics  I-^riiwid  is  reported  in  quite  a 
different  |x>sition.  Not  only  did  this  material  -*-rve  satis- 
factorily as  uniform  buttons,  but  it  replaced  numerous  other 
more  critical  plastics.  This  is  no  doubt  due  in  part  to  tin- 
different  climatic  conditions  prevalent  in  the  British  Me* 
and  in  part  to  somewhat  less  exacting  standards  than  are 
established  m  this  country.  TO  UK  IONTIN 


Special  Fixtures  for  Machinery 

<  (  niitiiiiit-il  /roiii  f'iii/c  34  i 


close  tin-  press,  effect  the  fastening  of  the  screen,  and  O|H-II 
(he  press  with  the  o|H-ration  completed.  Moreover,  .t  very 
secure  fastening  is  effected. 

Kuril  gear  shift   knobs  are  of  fairly   large  diameter  and. 
if  molded  solid,  would  have  thick  sections  that   w.>ui 
slowly  and  take  longer  to  mold.  Ix'-iilr-  requiring   more  of 
the   rather  ex|K-lisi\e  aceto  bntyrate   plastics   iis,-,|  and   run 
ning  the  risk  of  unsightly  shrink  marks.    For  these  HM-IHI*. 
the  knobs  are  molded  in  two  parts.  Ixith  hollow.    <  Mie  con- 
tains a  IMISS  with  the  hole  for  the  metal  shank,  over  which  the 
knob  is  fitted  subsequently,  and  the  other  is  merely  a  cap. 

I  hese  two  elements  are  cemented  together  and  held  under 
pressure  while  the  cement  dries.  .\  thin  layer  of  the  cement, 
made  by  dissolving  ]•  bntytate  in  solvent,  i-  |xmred 

onto  a  tray  and.  In-fore  each  jmir  of  moldings  is  put  together. 
-.lie-  i.f   them   is  dipped   into  the  thin   layer  of  cement   in  the 
.ml   picks   up  enough   of   the   cement    to   make   .1 

lollll 

I •  m.illy.  the  assembly   is   placed   in  mi> 


96 


I*  /.  .t  *  T 1 1  •* 


IMTOKKK    I'M., 


'  cesses  in  a  drum  that  is  turned  slowly  in  a  special  machine 
that  applies  pressure  to  the  knobs  while  the  cement  dries. 
Over  a  portion  of  the  drum  circumference  runs  a  flexible 
belt  held  under  tension  by  an  idler  pulley.  As  the  drum  car- 

[ries  the  knobs  under  the  belt,  the  latter  applies  pressure  to 
each  knob  and  it  remains  under  pressure  until  it  nears  the 
unloading  position,  where  contact  with  the  belt  ceases. 

Two  men  do  cementing,  loading  and  unloading  and,  when 
the  knobs  reach  the  unloading  station,  the  cement  has  dried 
and  the  assemblies  are  ready  to  be  removed,  after  which  the 
recesses  they  occupied  are  refilled.  Thus,  the  operation  is 

l  continuous  and  rapid,  but  yields  the  desired  results. 

These,  of  course,  are  only  a  few  of  the  more  uncommon 
operations  that  follow  molding,  but  they  make  use  of  rapid 
and  efficient  methods  and  equipment,  some  of  which  are 
unusual.  The  net  results  are  low  labor  cost  per  piece  and 
uniformity  in  processing,  making  for  products  that  serve 
their  purposes  well.  END 


Walking  on  Air  .  .  . 

(Continued  from  faye  63) 


included  discarding  of  contaminated  shoes  after  a  cure  has 
been  effected.  The  plastics  innersoles  permit  wearing  of 
such  contaminated  shoes,  provided  that  stockings  are  thor- 
oughly sterilized.  Tests  similar  to  those  made  by  the  U.  S. 
Army  Medical  Corps  were  conducted  by  Sears  Roebuck 
-Co.'s  test  laboratory  before  the  company's  stores  were 
authorized  to  buy  the  product. 

In  the  course  of  these  tests,  both  the  Army  and  Sears 
Roebuck  traced  a  cause  of  blisters  to  moist  stockings  which, 
coupled  with  warmth  and  friction,  induced  a  condition  espe- 
cially conducive  to  chafing.  This  follows  a  theory  that  foot 
perspiration,  in  the  humid  conditions  existing  inside  the 
shoes,  condenses  on  the  fabric  of  the  hosiery,  where  in 
the  natural  course  of  evaporation,  it  undergoes  a  change 
from  an  acid  to  a  salt,  with  altered  chemical  constituency — 
and  consequently  becomes  a  fertile  breeding  place  for  fungi. 

Constant  interior  ventilation  of  the  shoes,  as  provided 
by  using  plastics  ii.nersoles,  prevents  such  condensation  and 
^evaporation  by  eliminating  the  original  humidity. 

As  another  proof  of  their  ventilating  efficacy,  it  was 
found  by  army  doctors  and  others  that  workers  on  dusty 
Hi ii us  frequently  discovered  that  even  though  their  stock- 
ings remained  clean,  an  accumulation  of  dust  formed  in 
the  toes  of  their  shoes.  The  dust  drawn  in  by  air  suction 
which  accompanies  the  flexing  action  of  the  shoe  and  ven- 
tilators sifts  through  the  woven  fabric  to  the  shoe  sole, 
where  it  does  not  come  into  direct  contact  with  the  sock. 

\  standard  demonstration  of  the  manner  in  which  the 
shoe  ventilators  function  is  to  sprinkle  talcum  powder  on 
a  wearer's  sock  above  the  edge  of  the  shoe,  at  the  heel. 
After  the  wearer  has  walked  for  about  30  minutes,  most 
of  the  talcum  powder  is  found  in  the  shoe's  toe,  proving 
that  the  ventilator  allows  free  circulation  of  air  to  the  very 
tip  of  the  toes. 

Although  the  product  is  being  produced  in  five-ply  thick- 
nesses at  present,  expansion  to  thinner  innersoles  for  or- 
dinary dress  shoes  is  contemplated,  as  soon  as  increased 
supplies  of  the  fabric  and  additional  manufacturing  facili- 
ties are  available. 

Dale's  plans  include  moving  the  company  to  Newark, 
X.  I.,  location  of  the  Davis  Emergency  Equipment  Co., 
which  handles  industrial  distribution  of  the  product. 

In  the  meantime,  however,  the  five-ply  plastics  shoe  ven- 
tilators are  also  being  used  successfully  by  such  persons  as 
doctors,  dentists,  policemen,  mail  carriers,  barbers,  and 
others  who  spend  long  hours  on  their  feet — at  work  or  play. 


ORIGINALITY  WITH  ROOTS 


Clever  in  devising  forms,  assembly  and  effects  in  all 
types  of  plastics  for  products,  displays  and  containers. 
Cleverness  that  is  deep-rooted  in  long  experience,  in 
exceptional  facilities  and  in  competent  manpower. 
The  kind  of  cleverness  which  combines  the  ability  to 
create  with  the  ability  to  produce  economically, 
efficently  and  in  quantity.  That  is  the  service  we  have 
to  offer  —  originality  deep-rooted  in  practicability. 


INDUSTRIAL  CHEMICAL  CO. 

ElKINS  STREET,   SO.   BOSTON   27,  MASS 


PICTURE  OF  AN 

EXPEDIENT' 


'Often  the  hardest  way  to  do  a  simple  thing 

Has  the  rush  of  reconversion  caught  you  using 
expedients?  ...  If  so,  there  is  probably  a  place  in  your 
production  line  for  plastics.  .  .  .  Replace  those  critical 
items  with  plastics  instead  of  substandard  materials. 

R.E.C.  can  offer  you  quick,  practical  advice.  Our 
engineers  have  had  long  and  diversified  experience  in 
all  phases  of  plastic  planning  and  production.  R.E.C. 
will  gladly  help  you  —  whether  you  are  now  using,  or 
planning  to  use,  a  plastic  part. 

Simply  send  us  a  blueprint,  sketch,  or  sample,  and 
the    quantity    required  —  we'll    send    you    a    prompt 
"quote."  This  service  is  absolutely  without  charge. 
Address  Dept.  1258. 


OCTOBER  1946 


PLASTICS 


97 


4dvertiser 

Aaron  Machinery  Co 
Accurate    Molding   Corporation 
American  Decalcomania  Co.,  Inc. 
American  Molding  Powder  A 

Chemical   Corp 

Amos  Molded   Plastics 
Armour  and   Company     - 
Austin  Tool  a  Mlg.  Co 


Agency  fag* 


4dverfl«er 


xlgency 


Page 


Rothschild   Advertising   Agency 

Charles  Silver  A  Company 

H.  W.  Fairfai  Advertising  Agency.. 

Sidener  and  Van  Riper,  Inc 

Foota,  Cone  A  Balding 


Bambergtr,  A. 
Blaildel"  Pencil    Co 
Boonton    Maiding    Company 
Brllhert.  Arnold,  Ltd 

C.«  !..  Mfg.  Co..  Th. 

Cello-Plastic  Chemical  Co 

Celluplastic  Corporation 
Ciba  Product!  Corp     . 
Continental  Pl«tici  Corporation. 

Continental  Screw  Company 

Cumberland  Engineering  Co 


«7 
,    li 


20 
83 
•4 

73 


H    W.  Fairfai  Advertising  Agency 
Richard  A.  Foley  Advertising  Agency     . 

.The  Franklin   Fader  Company   15 

Henri  Le  Mothe  Agency  Back  Cover 

74 

The   McCarty  Company  81 

.  M.  C.  Diednch  Advertising 48 

.  Cory  Snow    Inc 70 

.Jim  Duffy,  Inc 75 

Rossi  I   Hirshson  U 

Richard  Thorndike  Precision  Advertising  77 


Detroit  Mold  Engineering  Co.   ...   Charles  M.   Gray   1   Associates  . 

Detroit  Stamping   Co Charles  Schweim  Company 

Duall   Molding  Corp Gunn-Mears  Advertising  Agency 

Ekstrom,  Carlson  a  Co 

Electric  Auto-Lite  Company,  The. 

Fenwel  Incorporated  

Fisher  Chemical  Company 


91 

n 


»al  Electric  Co 

Gering  Products,  Inc.       

Girdler  Corporation,  The 

Gits  Molding  Corporation 

Goodman,  Benjamin.  Inc 

Goodrich,  1    F..  Chemical  Co. 
Grays  Harbor   Industries,   Inc.   ... 
Great  American  Color  Company 


Haisall,  John.  Inc 

Henry's   Trucking    Company 
Hydraulic  Press  Mfg.  Co,  Th. 

Industrial   Equipment  Company  . 
Industrial  Molded  Products  Co. 
International   Plastic   Harmonica 
Corp 


Karlstad,  Andrew  C. 

Kingsley  Gold  Stamping  Machine 

Co 

Kirk.   F.   J.   Molding   Company... 
Krasilovtky.  David  <  Samuel. 

Trucking,  Inc 

Krieger  Color  1  Chemical  Co.  ... 


Cummings-Brand  A  McPherton M 

Ruthrauff  A  Ryan,  Inc 35 

Cory  Snow,   Inc.    14 

.Freiwald  A  Coleman  Advertising 82 

Benton  A  Bowles,  Inc S 

.M.  C.  Diedrich  Advertising 12 

Roche.  Williams  *  Cleary.  Inc 17 

.Merchandising  Advertisers  82 

Griswold-Eshleman  Co.  .  3e.  Second  Cover 

.Frederick  E.  Baker  and  Associates 76 

Bod ine  A  Meissner  Advertising 78 

.Anderson,  Davis  t  Ptatte,  Inc.  ... 
The  Jay  H.   Maish  Company 


85 

«4 
3 


.Louis  F.  Herman  Advertising  Agency...  85 
Wesley   E.   Sharer  a   Associates 8 


.Marcel  Schulhoff  1  Company 


...59 


Continental   Advertising   Service 93 

Cory   Snow,    Inc.  80 


Warren  P.  Fehlman  Agency H 


MANUFACTURER  WANTED 

to  mold  and  merchandise  new  line  of  patented 

WHISTLING  BALL  TOYS 

on  royalty  basis. 

Sampla  available  for  inspection 

Box  99,  '•',   PLASTICS,  185  N.  Wabash  Ave., 
Chicago 


EXTRUSION  DEPARTMENT  SUPERINTENDENT 

Knowledge  estimating,  dies,  production  control,  machines. 
Able  to  produce  to  close  tolerances.  Salary  and  commission. 
Progressive  eitrusion,  compression  and  injection  molder.  Reply 

Box  113,  C  O  PLASTICS,  185  N.  Wabash  Ave. 
CHICAGO   1.   ILLINOIS 


I  Oil    SALE 

Ml'-  I  H  K    MOID-    lo,    <\/.\;     Two  30 
lni<-i  lion  MnliN.    Pri\.  ii<-  IIUIIIT. 
lt.,v     III    r   a    Pla.llr.,    18.%    X.    «.,!..  .-I, 
1  hlmtfn.  III. 


\>. 


Kuhn  A  Jacob  Molding  A  Tool  Co..Eldridge-Northrop,  Inc 47 

Kurz-Kasch,    Inc Kircher,  Helton  A  Collert I?, 

La  Rose.  W.  T..  A  Associates Aldridge  A  Preston  Advertising 45 

Mack    Molding   Company George  Homer  Martin 7 

Magnetic    Plastics   Company Gregory  House,  Inc W 

Meyircord   Company,  The    C.  C.  Fogarty  Company 51 

Michigan  Chrome  A  Chemical  Co.. Karl  G    Behr  Advertising  Agency 78 

Michigan  Molded  Plastics,  Inc.  . .  .Wallace-Lindeman,  Inc 41 

Modern  Technical  Book  Company                                   H 

Mosinee    Paper  Mills  Company Klau-Van     Piatersom-Dunlap    Associates, 

Inc * 

National    Lock    Company L.  W.  Ramsey  Company 71 

National  Plastic  Products  Co.,  The  The  Joseph  A    Wilner  Company 84 

National  Vulcanized  Fibre  Co John  Gilbert  Craig  Advertising 13 

Nicholl  Hard  Chrome  Service 84 

Northern  Industrial  Chemical  Co.  .The  Callaway  Associates  «7 

Oiley,  John  H..  Company W 

Pennsylvania  Coal  Products  Co.  ...Lee  Murray  Advertising i 

Plaskon  Division,  Libbey-Owens- 

Ford  Glass  Company Meldrum  A  Fewsmith 10,  II 

Plastic  Service  Engineering *2 

Preis,  H.  P.,  Engraving  Machine 

Company  W.  O.  Nettleton  t  Associates M 

Printloid,  Inc Reiss  Advertising  IS 

Radio  Receptor  Company,  Inc.  ...O.  S.  Tyson  A  Company.  Inc.  31 

R  E  C  Mfg.  Corp Cory    Snow,    Inc 17 

Reed-Prentice  Corporation  Howard  Wesson  Company M 

Rohm  A  Haas  Company Newell-Emmett  Company  55 

Royle,  John,  A  Sons 41 

Schoder  A  Lombard  Stamp  A  Die 

Co..   Inc » 

Schwartz  Chemical  Co Walter  Wiley  Advertising.  Inc 12 

Scientific   Publishing  Corporation.  .The  Gravenson  Company,  Inc.  80 

Sleqel,   M.   8.,  Associates Craig  E.  Dennison  Advertising  Agency,  • 

Steiner,    George,   Company 14 

Stokes,  F.  J.,  Machine  Co McLain  Organization    21 

Strieker  Brunhuber  Co Aldridge  A  Preston  Advertising 81 

Tennessee  Eastman  Corporation Kenyon  A  Eckhardt,  Inc.  21 

Teion  Industrial  Corp.       M 

Topflight  Tool  Company Yorktowne   Advertising   Agency 

Van  Dorn  Iron  Works  Co.,  The The  Hubbell  Advertising  Agency 11 

Waterbury  Companies,  Inc Manternach.  Inc U 

Wiley.  John,  A  Sons,  Inc Ray-Hirsch   A   Waterston 

Wolf-Schrager  Corporation    

Worcester  Moulded  Plastics  Co.       C    Jerry  Spaulding,  Inc Third  Cover 

Wrigley,  Wm.  Jr.,  Company Ruthrauff  A  Ryan,  Inc 


CLASSIFIED  ADVERTISING 


PLASTICS.  SUrt  your  own  business  Immediately  with  I500-J600  capital. 
Complete  equipment  for  permanently  plastic  laminating  all  types  valu- 
able papers,  photos.  Identlflcatlon  cards,  badges.  He.  Write  for  free 
folder.  ITeco  Incorporated.  958  E.  81st  St.,  Los  Angeles  1.  Calif. 


FOR  SALE:  McNeil  t  ox.  Injection  molding  machine — hand  operated. 
Never  used.  Also  Z5t  IDS.  luclte.  Bernate  Products  Incorporated,  20! 
East  Third  Street,  kit.  Vemon,  New  York. 

FOR  SALE:  Plastic  Scrap  Granulator  No.  H  Cumberland  Complete 
with  S  H.P.  Motor,  completely  new.  Sydney-Thomas  Corp..  2351  Ferguson 
Road.  Cincinnati  5.  Ohio. 

A  WONDERFUL  opportunity  to  forge  ahead  with  a  growing  con< 
offered  by  an  Ohio  Custom  Molder  whose  business  Is  expanding  rapidly. 
There  Is  an  Immediate  opening  for  a  young  engineer  who  wants  to  progress 
and  whose  eiperlence  covers  designing  of  compression  and  Injection  moMi,l 
Please  state  fully  your  (tuallflcatlons  and  Indicate  salary  desired  Box  114, 
•  -  Plastics.  1M  N.  Wabash  Avenue.  Chicago  1.  III. 

FOR   RALE :    Plastic  molding  plant  compression   type  with   annual  sain 

IKiienilal  of  KiOO.OWl  to  J7!>0.000  In  large  mldweslern  city  In  good  labor 

area.  Inspection  Invited.  Box  116.  %  Plastlci.  185  N.  Wabash  Av«.. 
fhlragn  I.  Ill 

«  \MM>      i-lasilr    mold    tor    :.    nil*    Radio    Receiver    cabinet, 
photographs  dimensioned  and  priced.    Box  117,  %  Plastics,  1S5  N.  W.l.ish 

AM-  .    Chi,. it"    1.    Ill 

Ml  I P  WANTED 

-i  i-i  KIM  t  M'l  NT  for  small  progressive  Injection  molding  plant  In  Wl«- 
runsln  Must  be  practical  roan  Stale  previous  experience,  age,  salary 
desired.  Box  1M.  %  Plastics.  185  N.  Wabash  Avenue.  Chicago  1.  111. 


HP1CIAL18TB  on  plastic  battery  case  manufacture  Important 
organization  requires  outside  as»l«lanre  Work  on  fee  basis.  Stale  quali- 
fications siieclalty.  background  ami  references.  Box  lit.  '<  Plastics, 
IH  N.  Wai-ash  Avenue.  Chicago  1.  Ill 


!•  LAST  it'S 


(KTOHKK   1946 


In  most  operating  rooms,  surgeons  wear  rubber-soled  shoes 
or  other  insulating  footwear  as  a  precaution  against  highly 
dangerous  static  sparks  in  the  ether-charged  atmosphere. 
With  rubber  footwear,  excessive  foot  perspiration  and  con- 
sequent corollary  troubles  frequently  resulted.  The  plas- 
tics Shoe  Ventilators,  however,  as  was  discovered  by  a 
group  of  surgeons  in  a  mid-west  clinic,  are  efficient  pro- 
tection against  foot  ills  which  were  formerly  caused  by 
continued  use  of  the  rubber  footwear. 

Another  outstanding  advantage,  because  of  the  material's 
non-absorptive  qualities,  is  that  the  ventilators  are  readily 
cleanable  with  soap  and  water.  The  fact  that  its  resiliency 
combats  the  compacting  which  occurs  with  other  woven 
materials,  making  the  ventilators  practically  wear-proof,  is 
described  as  an  additional  feature. 

Dale  is  planning  also  to  expand  the  uses  of  Lumite 
fabric  to  various  parts  of  women's  apparel,  as  soon  as  suf- 
ficient supplies  of  the  fabric  and  of  fabricating  equipment 
become  available. 

These  apparel  items  include  the  pads  used  to  fill  out 
shoulders ;  under  arm  shields  to  protect  dresses  from  pers- 
piration stains,  and  the  pads  used  by  some  women  to  aug- 
ment their  natural  bust  contours.  These  products  are  at 
present  being  made  of  cotton  batting  encased  in  rayon  or 
nylon,  or  of  plied-up  layers  of  cotton  fabric  similarly  en- 
cased. 

In  shoulder  pads,  the  plastics  fabric  can  be  plied  up  to 
the  same  thicknesses  as  those  currently  provided  by  cotton, 
at  the  same  time  providing  the  features  of  air  circulation, 
lightness  and  easy  cleanability  which  distinguish  the  shoe 
ventilators.  The  pads  should  be  particularly  desirable  in 
the  summertime,  it  is  believed,  when  conventional  shoulder 
pads  might  be  conducive  to  excessive  warmth  and  perspira- 
tion. 

The  same  advantages  are  claimed  for  the  dress  shields, 
with  an  additional  benefit  in  the  fact  that  possibility  of 
stains  from  perspiration  salts  is  eliminated.  The  shields 
avert  formation  of  perspiration  by  removing  conditions  of 
warmth  and  humidity  which  foster  it. 

The  bust  pads  will  be  piled  up  in  the  same  manner  as  that 
used  for  shoulder  pads  and  dress  shields;  they  will  then  be 
heated  sufficiently  to  permit  shaping  in  the  form  of  cups. 
Once  formed  in  this  manner,  it  is  said  that  they  will  retain 
their  shape  indefinitely.  They,  too,  will  have  the  advan- 
tages of  lightness,  coolness  due  to  more  ventilation,  easy 
cleanability  and  long  wear.  END 


Insulating  High  Frequency  Cables 

(Continued  from  page  27) 


minimum  displacement  of  inner  conductor  on  flow  test, 
unbroken  sequence  of  high  quality  of  inner  conductors  and 
outer  shields  and  absence  of  corona  effect  at  high  voltage. 

A  brief  description  of  two  of  the  tests  exemplifies  the 
quality  demanded  in  high  frequency  cable.  In  the  cold  bend 
test,  a  sample  of  the  cable  is  subjected  to  a  temperature  of 
— 40°C  for  two  hours  and  then  bent  over  a  mandril  ten  times 
the  outside  cable  diameter.  If  either  the  jacket  or  the 
polyethylene  cracks,  the  cable  is  rejected. 

In  another  test,  to  determine  heat  deformation,  the  cable 
is  placed  in  a  heating  unit  and  held  at  a  temperature  of  98°C 
(205°F)  for  7J/2  hr  with  weights  on  the  center  conductor. 
The  cable  is  then  inspected  by  fluoroscopic  X-ray  to  locate 
any  deformations,  and  particularly  to  see  whether  the  inner 
conductor  has  left  dead  center.  This  center  wire-core  must 
remain  within  10%  of  dead  center,  which  permits  a  toler- 
ance, in  some  cases,  of  approximately  ±  .005". 

The  importance  of  high  frequency  cable  cannot  be  empha- 
sized too  greatly,  for  upon  it  depends  the  fulfillment  of  the 


•  Cerlain  plastics  withstand  heat 
better  than  others.  Some  are  particu- 
larly adapted  for  jobs  that  must  with- 
stand wear.  Others  are  best  for  ma- 
chining and  threading.  •  The  secret 
V  of  success  in  plastics  is  in  knowing 

V          the  right  plastic  to  use  for  the  job  at 
\         hand.  •  Ask  us  to  help  you  see  what 
\        plastics  can  do  in  your  business. 

• »>X       •  Just  send  photo,  sample  or  specifi- 

>.    cations,  and  we'll  tell  you  quickly  if 
\  it  can  be  made  in  moulded  plastics. 


THE  MAGNETIC  PLASTICS  CO. 

1900   EUCLID   BUILDING      •      CLEVELAND   15,   OHIO 


MANUFACTURERS     OF 


ANY     COLOR  ANY    FlOW 


OCTOBER  1946 


i'LASTlCS 


99 


Ingenious  New 

Technical  Methods 


To  Help  You  with  Your 
Reconversion  Problems 


New  Micro  Square  Instantly  Checks 
Right  Angles  to  One  10,000th  Inch! 


Ideal  for  precision  testing,  the 
Aero  Micro-Sine  Square  quickly 
and  accurately  checks  right  angle 
work  to  I/ 10,000th  inch  within 
a  given  distance.  Its  standard  in- 
dicator dial  instantly  registers 
error,  location  of  error,  and 
amount  of  correction  required. 
Designed  for  tool  and  die  shops, 
machine  shops  and  testing  labo- 
ratories, it  also  provides  a  stand- 
ard for  checking  master  squares, 
triM|ii.irc.-s  and  tools. 

The  Aero  Micro- Sine  Square  is 
very  simple  to  operate,  saves 
hours  of  time.  Made  of  hardened 
cool  steel,  in  ground  and  lapped 
precision  construction.  Available 
in  two  types:  (I)  Standard  pre- 
cision gauge  in  tenths,  (2)  Lever 
indicator  in  thousandths.  Both 
complete  with  master  checking 
blocks  and  carrying  cases. 

On  precision  jobt, requiring  a  stat- 
ic position  and  mental  alertness, 
workers  undergo  nervous  tension 
which  often  results  in  fatigue. 
Tests  have  shown  that  the  act  of 
chewing  helps  relieve  tension — 
helps  workers  stay  alert,  thus  in- 
creasing their  efficiency  to  do 
more  accurate  work.  For  this  rea- 
son, many  plant  owners  urge 
workers  to  chew  Wrigley's  Spear- 
mint Gum  on  this  type  of  job. 

You  can  fit  cnmplfti  information  from 

Aero  Ttol  and  Dii  Vorla 
4))4  BnaJtmj,  Cbitagt  40.  ////*»» 


Standard  Indicator  Dial 


promi.M-  nl'  tlu-  entire  electronic*  industry  and  all  it*  related 
off-hoot-,  from  television  broadcasting  anil  reception  to 
tnUtfportation.  In  each  of  these  field-.  Amphenol  ha-  engi- 
neered cable-  designed  to  answer  the  -|>ecitic  problem-  it 
HUM--.  A  recent  development  in  television,  lor  example,  is 
Amphenol's  Turn- Lead  TraiiMiiission  Line,  which  carries 
signals  from  antenna  to  KM  and  television  with  minute  loss. 
Made  of  polyethylene  dielectric,  it  is  unaffected  by  acid*, 
alkali-  and  oils,  it  can  remain  flexible  in  temperature-  a-  low 
as  — 70°K.  and  it  doe-  not  Ix-come  brittle  even  after  continu- 
oti-  aging  in  sunlight. 

Still  another  plastic-  high  frequency  cable  application 
which  -hould  come  into  widespread  ti-e  in  the  future  i-  the 
Ampin-mil  I'a— eiiger  Car  Antenna.  I  lie  time  ha-  come 
again  when  the  nation'-  railroad-  will  Ix-  occupied  with  pro 
vicling  lietter  service  and  with  making  rail  travel  more 
plea-ant  and  luxurious  than  it  ha-  ever  IK-CII.  In  the 
approaching  era  of  coni|x-ting  for  customer-favor,  the  ability 
to  offer  noise-free,  home-like  radio  reception  in  railroad 
passenger  cars  will  IK-  a  definite  -ales  argument. 

Radio  reception  on  moving  train-  pre-ents  problem-  that 
are  probably  unparalleled  elsewhere  in  the  radio  field.  \ 
sensitive  receiver  i-  also  sensitive  to  interfering  volt.ii;i--.  •>! 
which  there  are  many  in  railroading.  The  new  antenna  vir- 
tually eliminate-  noi-e.  mainly  by  complete  insulating  of  the 
antenna  and  -hielded  lead-in.  It  keep-  nut  electrical  dis- 
turbance- from  within  the  train  itself,  from  communications 
and  power  line-  jmrallel  to  the  right-of-way  and  from  over- 
head power  lines  on  electrified  roads.  It  also  eliminates 
-tatic  electricity  discharged  hy  particles  of  dust,  coal  dust, 
-and  and  -now.  In  addition,  the  antenna  i-  completely 
weatherproof  in  it-  housing  of  polyethylene,  which  also  pro- 
vides protection  to  personnel  and  radio  equipment  in  ca-e 
a  power  line  should  fall  across  the  antenna. 

These  aie.  of  course,  hut  two  tiny  corners  in  the  vast  field 
of  electronics,  but  they  are  good  examples  of  the  importance 
of  high  frec|iiency  cable-.  They  are  also  further  reminders 
of  the  manner  in  which  plastics  is  helping  to  harness  the 
forces  of  nature  in  the  service  of  mankind.  KND 


Progress  in  Injection  Molding 

(Continued  from  [>agc  24) 


A*   89 


a  -pecial  cylinder,  which  maintains  a  constant  tcni|x-raturc 
of  .sdO"  F.  A  z-nickel  lining  eliminates  jiossibility  of  cor- 
rosion and  a  copper  jacket  evenly  distributes  the  heat. 

Selection  of  material  for  this  precision  operation  de- 
manded careful  weighing  of  the  nuinerou-  requirement-. 
Stability  in  molding  and  curing  was  of  great  ini|>ortaiK-e. 
Kurthcr.  the  spray  assembly  had  to  IK-  resistant  to  moisture 
absorption  ami  inert  to  alcohol  and  many  chemical-  Km 
these  rea-on-  a  vinyl  pla-tic-  wa-  adopted,  of  a  milk  white 
color. 

A    trail-parent    acrylic    cover    for    the    nasal    tip   al 
injection    molded    in    a    -ixcaxity    die    to   complete    the   as- 
sembly. 

Another  mold  fabricateil  by  the   l.o-  Angeles  firm  made 
full  use  of  die  capacity  in  forming  nine  electric  -w  itch  plates 
with  one  -hot.     This  wa-  done  with  runner-  .Md"  w  i. 
Mi"   clcep.     The    timid    wa-    machined    with    -uch    accuracy 
that  scarcely  any  flash  i-  found  when  it  o|ien-  to  dischari 
the   part-. 

Switch  plate-  in  several  designs  were  ca-t  by  thi-  oper. 
tioll.      The  die  could  have  held   1(1  of  the  Usual  ••!/>•.  but  om 
wa-  twice  the  u-ual  dimcn-ion-  a-   it   w.i-  designed   lor  a 
double  switch. 

An  ixory  jmly-tyrctic  wa-  u-ed  for  the  plate-.      I'o  h 
stability,  high  dielectric  strength  and  resistance  to  alcohol  or 
chemical  attack-.  Plastic  I  Me  \    1'iml  u-e-  -iich  )HI|\-|, 
as  /  uslrun  and  \fvr.in  for  work  of  this  character.  i  MI 


100 


I*I..\STH  * 


(MTOHKR 


Information 


We   weigh    the   value    of   production    in 
terms  of  quality,   quantity,   and   prompt 
delivery  to  the  customer  exactly  when 
needed.    As    the    largest    plant    in    the 
East  devoted  to  Custom  Injection  Mould- 
ing   exclusively,    our    service    is    com- 
plete   from    product    engineering    to 
final  inspection.  We  design  and  build 
our  own  dies,  and  maintain  a  daily 
24    hour    moulding    schedule,    with 
the    capacity   and    ability   to    meet 
your    most    detailed    requirements. 
Because  we  are  custom  moulders, 
our  entire  organization  including 
expert  engineers,  designers  and 
moulders  is  integrated  with  your 
plans.    Isn't   this   worth    looking 
into? 


Vudfom  Jriuetfion  tSvloutdina 

WORCESTER  MOULDED  PLASTICS  CO. 

14  HYGEIA  STREET,  WORCESTER  8,  MASS. 

IT  East  42nd  St.,   New  York   IT,   N.   Y. 
120  West  Chippewa   St.,   Buffalo   2,  N.   Y. 


Arnold  Brilhart  Ltd.  a*  licensee 
of  the  GITS  CRYSTAL-SEAL  proce* 
'/f^/'/r  for  additional  information. 


ARNOLD         BRILHART        LTD. 

435  Middleneck  Rd.    •    Great  Neck,  N.  Y.    •    Phone  Great  Neck  4054 


VEMBER 
1946 


Y.A 


THIS  year's  Christmas  tree  lights  made  by  Noma  will  feature  wire  insulation  made 
from  GEON.  They  will  be  safer  because  the  insulation  is  self-extinguishing  in  case 
of  fire.  The  strings  will  be  lighter  weight,  easier  to  handle  because  the  insulation  is 
thinner,  smoother,  more  flexible,  than  old-fashioned  insulation.  They  will  last  longer 
because  the  insulation  resists  wear,  aging,  heat,  and  flexing — won't  ever  get  gummy,  crack, 

or  peel  from  the  wire. 

These  properties,  plus  resistance  to  oil>  and 
greases,  foods  and  chemicals,  water,  aciil-. 
mildew,  sunlight,  and  most  other  normally 
destructive  factors,  have  made  versatile 
GEON  the  ideal  material  for  literally 
hundreds  of  products  in  the  home 
and  in  industry. 

GEON  can  be  pressure  or  injection 

molded,  extruded,  calendered  or  cast  into  sheet  or  film,  applied  as  a  coating  to 
textiles,  fibres,  and  papers.  Products  made  from  GEON  may  be  brilliantly  or 
delicately  colored,  flexible  or  rigid,  clear  or  opaque.    While  we  make  no 
finished  products  from  GEON,  we'll  be  glad  to  work  with  you  on  special 
applications.  Just  write  Dept.  U-ll,  B.  F.  Goodrich  Chemical  Company, 
Rose  Building,  Cleveland  15,  Ohio.  In  Canada:  Kitchener,  Ontario. 


B.  F.  Goodrich  Chemical  Company 


*  0»v*«0»«0> 
T»«  ».  f.  OCOWH.M  CO 


DON'T  LET  SIZE  OR 


EIGHT  LIMIT  YOU! 

PLASTICS 
APPLICATIONS! 


icilications  ol  part  illustrated  above:  Projected  Areo  —  153  squore  inches;  Weight  —  18  ounces, 
iduction  —  30  pieces  per  hour,  Molder  —  The  Standard  Products  Company 


This  polystyrene  refrigerator  compartment  door  is  typical  of  large 
area  moldings  now  being  produced  with  H-P-M  multi-chamber  in- 
jection machines.  Due  to  the  ease  of  removing  finished  parts  from 
the  machine,  the  H-P-M  downward-acting  hydraulic  mold  clamp 
has  proven  far  superior  for  production  molding  of  large  parts.  Also 
molds  are  more  accessible  for  positioning  inserts.  The  injection  of 
material  at  more  than  one  source  provides  practically  unlimited 
injection  capacity  design. 

If  you  are  anticipating  the  production  of  large  area  parts,  beyond 
the  scope  of  standard  single  chamber  injection  machines,  H-P-M 
welcomes  the  privilege  of  studying  your  particular  requirements. 

For  your  smaller  jobs,  H-P-M  offers  you  a  standard  line  of  4,  9 
and  16  ounce  capacity  "all-hydraulic"  injection  machines,  which 
can  be  delivered  promptly  from  stock. 

THE    HYDRAULIC    PRESS    MFG.    COMPANY 

Mount  Gi/ead,  Ohio,  U.  S.  A. 


Branch  Of(ic«j  in  New  York,  Philadelphia,  Cleveland,  Cincinnati, 
Detroit,   and    Chicago.    Representatives    in    other   principal    cities. 


NJECTION  MACHINE! 

OR       MOLDING       PLASTIC 


November,   1  946 


plastics 


in  this  issue 

Plastics  Dominate  New  Aircraft  Interiors Gilbert  C.  Close  15 

"Topping"  Vinyl  Sheet Mel  Meyers  18 

Laminating  for  Glare- Proof  Surfaces Jack  D.  Stratton  20 

Models  Aid  Design David  H.  Rubin  24 

Edgelighting  Murals  30 

Building  Better  "Shakers" V.  E.  Gibbens  32 

Aircraft  Feature  New  Laminates 34 

Designing  Functional  Furniture Louise  Sanders  37 

How  Plastics  Combine  With  Die  Castings Herbert  Chase  40 

"Plexon"  Styles  Millinery 46 

Building  Scale  Models  With  Vinyls M.  Church  50 

Plastics  Cases  for  Museum  Specimens 52 

Color  Is  Added  to  Plastics  Tableware 56 

Know  Your  Caseins,  Part  II Dr.  George  H.  Brother  58 

Compression  Mold  Design,  Part  III John  G.  Robb  62 

How  Phenolic  Resins  Combat  Corrosion 64 

Extrusions  Take  on  New  Jobs 66 

"Engineering"  a  Plastics  Toy 74 

Small  Pump  Gives  Big  Output 84 

Decorating  Greeting  Cards Philip  Pollack  90 


departments 


Plastics  in  Perspective 12      People    81 

On  the  Drafting   Board 49 

I'l.i-n.  -  at  Work 54 

What's  New  in  Plastics 69 

Literature   Review    70 

Knii nrer in c.  News  Letter 72 

Industry   II itUixl.t-   80 


Association   Activities   83 

I'la-tics.  Overseas    93 

The  Plastics  Library 95 

Statistical  Data    99 

Problems  in  Plastics 100 


COPYRIGHT,   1944 


ZIFF-DAVIS  PUBLISHING  COMPANY 


Editorial  Offices.  185  N.  Wsbash  Ave..  Chicago  I.  III. 

WILLIAM  B.  ZIFF 
Chairman  of  Ike  Board  and  PmbUikrr 

B.  G.  DAVIS 
President 

i.  .if.  .1/1     GEORGE  BERNER.  Adferliiing  and  Sales  Director 
MICHAEL  H.  FROELICH.  Editorial  Director 
H.  |.   MORCANROTH.  Production  Director 
H.  G.  STRONG.  <  irculation  Director 
ARTHUR  T.  PULLEH.  Secretary  Treasurer  HERMAN  R.  BOUIN,  An  Director 


Clrcul<He»l 


VOLUME  5,  NUMBER  5 

IDITOKIAL     STAff 

MICHAEL  H.  FROELICH 

Editor 
WILLIAM  SCHACK 

h'ieid   Editor 

M.  CHURCH 

Associate   Editor 

LILA  SHAFFER 

A  isociott   Editor 

G  AITHER   LITTRELL 

Writ  Coast  Editor 

FRED   H  AMLIN 
H'aihington  Editor 

rHAB'-">  A.  SCOGLAND 

Consulting  Technical  Editor 

WALTER   STTINHARD 

Staff  Photographer 

ARTHUR  E.  H  AUG 

Staff  Photographer 

SYDNEY  BARKER 

Art  Editor 


JAMES  A.  CERBONE 
Emit  en  Advertising  Manager 

ROY  E.  UNDER 
tlidweit  Advertising  Manager 


CHARLES  H.  TIGHE 
Manager,  Eastern  Division 

WILLIAM  L.   PINNEY 
Manager,   Western  Division 

BRANCH      OFFICES 

NEW  YORK  (1) 
Empire  State  Bldf..  Wl  7-tt»0 

LOS  ANGELES  (U) 
Hi  5.  Hill  St..  TUcker  9213 

WASHINGTON   (4) 
International  Blag.,  EXErntive  lit! 

TORONTO 
21  King  Street,  East 

LONDON  (W.i) 

Zif -Davis.  Limited 

Grampians  Bldg.,  Western  Gate 


COVER 

A  colorful  assortment  ol 
the  new  molilure  proof 
sail  and  pepper  dispen- 
sers, made  ol  "Plaskon." 
now  being  marketed  by 
Ihe  Sonette  Plastics  Co. 
Photo  by  Arthur  E.  Hauq 


Other  Zitt-Davis  Publicetioni:  Hying,  Popular  Photography.  Radio  News.   Radio-Electronic   Engineering. 


mfttertftl     «• 

— *---Jjt»t{ 


PLASTICS 


NOVKMHKK   1946 


tf* 


'+&+ 


with  the 


famousThermexdra^er 


these  advantages: 


Get  a 


THERMEX  Red  Heads  are  a  product  of  The  Girdler  Corporation, 

Thermex  Division,  Louisville  1,  Kentucky.    District  Offices: 

150  Broadway,  New  York  City  7,  New  York 

228  North  LaSalle  Street,  Chicago  1,  Illinois 

1836  Euclid  Avenue,  Cleveland  15,  Ohio 


Widest  range  of  fully  developed  models  from  which 
to  fit  your  needs 

Developed  especially  for  the  plastics  industry 

Compactly  designed  to  fit  present  press  layouts 

Dual  timer  control 

Every  model  portable 

Easy  to  install 

Completely  self-contained 

Dependable 

Simple  to  use 

With  the  exclusive  sliding  drawer  heating  compartment 

Automatic  signal  light 

Automatic  resetting  timer 

Convenient  working  height 

Accessible  control  panels 

Large  load  area  that  takes  small  and  large  preforms 

Warp-proof  load  drawer 

Adequate  metering 

Overload  and  underload  protection 

Automatic  safety  switches  on  sliding  drawer  and 
maintenance  doors 

Air-gap  with  all  loads 

Maximum  uniformity  of  heat 

Condensation  moisture  eliminated 

Efficient  air  cooling  system 

Rugged  construction 

Heavy-duty  copper  plated  cabinet 

Maximum  protection  against  radiation  leakage 

Economical  power  consumption 

Service  by  fully  qualified,  factory-trained  specialists 


THERMEX  and  RED  HEAD 
Trade  Marts  Reg.U.S.Pat.Off. 


NOVEMBER  1946 


PLASTICS 


W;  „<>„>  MOTLETONE  9,w  „ 

*utf±/t  .  .  .  faulu 

Use  metal . . .  plastic  ...  or  wood  —  with  Motletone  a  single  spray-coat  application 
gives  it  that  lustrous  hammered  finish  effect  that's  so  popular  today.  What's  more, 
your  regular  spraying  equipment  does  100%  of  the  job.  Because  of  its  smooth  yet 
hammered-like  appearance,  Motletone  tends  to  hide  weld  marks,  scratches  or 
other  small  defects,  and  that  means  fewer  rejects  and  additional  savings  of  pro- 
duction time. 

This  new,  durable  M&W  production  finish  is  now  available  in  a  complete  range 
of  colors,  formulated  for  either  baking  or  air-drying  schedules.  Write  for  Technical 
Data  Bulletin  108  and  sample  color  cards  or  arrange  to  have  an  M&W  technical 
consultant  discuss  your  own  requirements  with  you. 


PIONEERS 
IN   mOTECTION 


u  avet 


MAASV  &  WALDSTEIN  COMPANY 


NEWARK  4, 
NEW  JERSEY 


1658  Carroll  Avenue.  Chicago  12          •          6  Jersey  Street,  Boston  15          *  J0751   Venice  Blvd.,  Lot  Angelei  34 

PRODUCERS    OF    LACQUERS,    ENAMELS,    SYNTHETICS    AND    SPECIALIZED    PRODUCTION    FINISHES 


- 


PI..\STH'9i 


NOVKMHKR  194fl 


STOKES 

Preform  Pres 


Choice  of  the  Plastics  Industry 
Since  Its  Beginning 


STOKES  Preform  Presses  are  preferred  equipment  in 
modern  molding  plants.  They  meet  present-day  de- 
mands for  larger  preforms  ...  for  rugged  machines  that 
withstand  hard  service  in  long  production  runs.  They  offer 
a  wide  choice  of  equipment  from  which  to  select  presses 
to  best  meet  individual  requirements. 
For  Large  Preforms  up  to  4"  dia  ,  the  heavy-duty  Stokes 
No.  280  is  recommended  ...  a  toggle-type  press,  with 
4"  die  fill,  applying  up  to  80  tons  pressure.  Other  presses 
are  available  for  pressures  from  100  to  300  tons  capacity. 
For  Large  Output  use  a  Rotary  type  press  .  .  .  makes 
balls  or  standard  shapes  up  to  1  3/16"  dia.  at  300  to  350 
per  min.  We  build  eight  different  models  and  sizes  of  this 
type  press  with  output  up  to  1000  per  minute. 
For  Genera/-Purpose  Preforming  we  offer  versatile  Single 
Punch  Presses,  readily  changed  from  one  job  to  another. 
Four  models.  The  "R"  machine  shown  has  2"  die  fill, 
makes  preforms  up  to  2'/2"  dia.  at  production  rates  up 
to  50  per  minute. 

Stokes  Preform  Presses  are  rugged,  of  semi-steel  con- 
struction, with  working  parts  thoroughly  protected  from 
dust.  Equipped  with  Automatic  Excess  Pressure  Release, 
to  prevent  jamming.  Easily  adjusted  for  preform  hardness 
and  weight. 

F.     J.     STOKES     MACHINE     CO. 
6040  Tabor  Road  Philadelphia  20,  Pa. 


SEE  "ROBOTS  AT  WORK" 

...  a  new,  colorful,  instructive,  entertaining  16  mm.  sound  motion 
picture  that  tells  the  story  of  Completely  Automatic  Plastics  Molding. 

It  shows  compression  molding  from  hand  to  completely  automatic 
production  methods.  Photographed  in  full  Kodachrome.  Narrated  by 
Lowell  Thomas.  Running  time  30  minutes. 

Prints  are  now  available,  loaned  for  showings  before  company  groups, 
technical  societies,  engineering  schools  and  colleges. 

Write  for  a  booking,  giving  a  choice  of  two  or  three  dates  if  possible. 


GENERAL  PURPOSE 


HIGH  PRODUCTION 


HEAVY  DUTY 


AUTOMATIC 
TABLETTINO  EQUIPMENT 


NOVEMBER  1946 


PLASTICS 


DESIGNED      AND      ENGINEERED      AT      NO.      1      PLASTICS      AVENUE 


MOLDED   PLASTIC  STANDS  THE  TEST  OF  TIME 


LEATHER  watchstraps  just  couldn't  take  the  beating  of  jungle 
conditions.  They  rotted  in  no  time.  And  too  many  irreplaceable 
watches  were  being  lost  in  the  field  during  the  war. 

The  Hamilton  Watch  Company  asked  General  Electric  if 
plastics  could  do  something  to  solve  this  serious  problem. 

Nylon  was  selected  as  the  material  because  it  is  impervious 
to  sweat  .  .  .  fungus  ...  rot  ...  salt  water.  But  nylon  had 
never  before  been  molded,  like  this.  A  special  new  nylon 
molding  compound  had  to  be  obtained.  Then  No.  I  Plastics 
Avenue  specified  the  processes  whereby 
molded  nylon  watchstraps  could  be  pro- 
duced economically  in  quantity. 

This  is  one  more  case  of  plastics  en- 
gineered to  the  job  doing  what  no  other 
known  material  can  do.  If  you  have  a 
problem  that  plastics  might  solve,  bring 
it  to  General  Electric.  G.  E.  is  the  world's 
largest  manufacturer  of  finished  plastics 
products.  Plastics  Divisions,  Chemical 


EVERYTHING  IN 


Department,  General  Electric  Company,  1  Plastics  Avenue, 
Pittsfield,  Massachusetts.  Whv  not  send  for  the  new  illustrated 
booklet,  "  What  Are  Plastics?" 

G-E  Complete  Service  — Everything  in  Plastics 

Backed  by  52  years  of  experience,  we've  been  designing  and  manu- 
facturing plastics  products  ever  since  1894.  C-E  Research  works  continu- 
ally to  develop  new  materials,  new  processes,  new  applications. 

No.  1  Plastics  Av«nu«__comp|cte  plastics  scnicc  -engineering, design 
and  mold-making.  Our  own  industrial  di- 
and  engineers,  working  together,  create  plas- 
tics parts  that  are  both  scientifically  sound  .md 
good-looking.  Our  own  toolrooms  are  manned 
by  skilled  craftsmen— average  precision  mold 
experience,  12  years. 

All  types  of  plastics.  Facilities  for  compref 
sion,  injection,  transfer  and  cold  molding  .  . 
for  both  high  and  low  pressure  laminating  . , 
for  fabricating.  And  General  Electric  Quality 
Control  —  a   byword    in    industry  —  means   I 
many  as   160  inspections  and  analyses  for  • 
single  plastic  part. 


GENERALS  ELECTRIC 


General  Electric  plastics  factories  art  located  in  Fort  Wayne,  Ind.,  Meriden.  Conn..  Scranlon,  Pa.,  Taunion.  ttrst  Lynn,  and  Pittsfield,  Mast, 
8  PLASTICS  NOMvMHKK    I'Ufi 


Football 


isn't  played 


Clad  in  track  suit,  what  chance  would  a  player 
have  against  a  team  equipped  with  the  "armored" 
togs  of  football! 

In  many  phases  of  production  involving  paper 
.  .  .  essential  industrial  papers,  that  is ...  it  also 
becomes  vital  to  provide  proper  physical  and 
chemical  characteristics  to  withstand  "unneces- 
sary roughing".  Modern  MOSINEE  papers  for 
the  plastics  industry,  for  instance,  are  engineered 
specifically  for  plastics  requirements.  For  the 
electrical  industry  and  other  mechanical  applica- 
tions, MOSINEE  paper  characteristics  are  pro- 


MOSINEE  •  WISCONSIN 


track  trunks 


vided  for  maximum  arc  resistance,  high  dielectric 
strength,  low  moisture  absorption,  high  strength- 
weight  ratio.  For  other  products  and  processes, 
MOSINEE  creates  special  stretching  papers,  high 
tensile,  high  fold  and  tear  resistance,  high  absorp- 
tion or  moisture  repellency  papers  . . .  controlled 
maximum-minimum  pH,  and  other  scientifically 
created  papers  . . .  dependable  in  uniformity  and 
performance. 

MOSINEE  paper  technicians  are  prepared  to 
equip  the  paper  you  need  with  characteristics  that 
improve  product  and  production.  Call  MOSINEE. 


PAPER 

MILLS 

COMPANY 


Please  address 

your  letter 

Attention 

Dept.  E" 


WVEMBER  1946 


PJLASTI  CS 


w/f/i  IfSS  DOWN-TIME 


and  FEWER  REJECTS! 


This  highly  versatile  new  Defiance 
Plastic  Preform  Press  solves  a  wide 
range  of  preform  problems— for  many 
shapes  and  sizes.  It  does  the  \o\>  faster. . . 
with  greater  accuracy . . .  and  lower  costs! 
Built  for  high-speed  production — 
with  advanced  Defiance  features  de- 
signed by  plastics  engineers  for  the  plastics 
industry.  Die  and  color  changes  in 
30  minutes— not  4  or  5  hours.  Also, 
you  can  adjust  density  and  fill  while 
machine  operates.  Assures  high  uni- 
formity of  weight  and  density— with 
fewer  rejects,  small  flash,  less  handling 
and  filing.  Easy  to  clean.  Precision- 
built  for  utmost  dependability.  Write 
for  latest  bulletins.  Defiance  Machine 
Works,  Inc.,  Defiance,  Ohio. 


DEFIANCE 

PLASTIC  PREFORM   PRESS 


Dtfitmu  Pl*ml — ohrrc  >ccu»cr  11 
ihe  watchword  throughout  operation*. 


In  utemhlini  Offline*  Clinic  Pre»»e»— experi- 
enced engineer*  keep  •  watchful  eye  on  preciiion. 


10 


Uhoritory  letting  pliy*  »n  important  part  in 
Dchantc  production. 

NOVEMHKK  1946 


In  the  famous 
LIONEL  ELECTRIC  TRAINS 


Molded  by  the  Lionet  Corporation 

0  Lionel  Electric  Trains  are  back— with  new  features  that  will  delight  the  heart  of  every  youngster  and  railroad  fan.  And 
playing  an  important  part  in  this  happy  return  is  Chemaco  Ethyl  Cellulose,  chosen  for  car  bodies  because  of  its  lightness 
and  resistance  to  impact.  Even  when  roughly  handled,  these  Lionel  cars  will  not  break  or  dent.  The  colors  go  all  the  way 
through,  except  on  the  tank  car,  on  which  aluminum  paint  has  been  applied.  In  addition,  Chemaco  Polystyrene,  because 
of  its  excellent  electrical  insulation  properties,  is  used  as  part  of  the  magnetic  coupler  and  as  a  base  strip  beneath  the  motor. 
Thus  Chemaco  Molding  Powders  are  adding  a  modern  "plus"  to  a  popular  mass  production  line.  Chemaco  engineers  and 
Chemaco  Molding  Powders  (Ethyl  Cellulose,  Cellulose  Acetate  and  Polystyrene)  are  ready  to  assist  you  in  meeting  your 
problems.  Your  inquiries  will  receive  prompt  attention. 


Ckemaco 


A    subsidiary    of    Manufacturers    Chemical    Corporation 
Berkeley    Heights.    N.    J.     •     Branch   Office   in   Cleveland 


NOVEMBER  1946 


11 


p 


IASTICS 


As  "WE  go  to  press,  negotiations  are  at  a  stalemate 
between  the  Society  of  the  Plastics  Industry  and 
the  Society  of  Plastics  Engineers  on  the  question  of 
this  year's  plastics  exposition.  The  original  plan  of  the 
engineers'  group  calls  for  a  show  in  January,  while 
the  management  group  scheduled  an  exhibition  for 
May.  Last  year,  when  the  two  groups  held  expositions 
and  sessions  in  Detroit  and  in  New  York,  the  duplica- 
tion was  somewhat  tough  on  the  exhibitors  so  far  as 
expense  and  time  were  concerned.  But  at  least  the 
plastics  industry  was  presented  to  different  publics. 
This  year,  however,  both  shows  are  scheduled  for  Chi- 
cago, cancelling  out  that  benefit,  leaving  only  the  cost 
and  the  trouble,  and  the  situation  becomes  a  purely 
intra-industry  matter.  Chicagoans  do  not  care  who 
stages  the  show ;  neither  do  the  industrial  visitors  and 
other  end-users  of  plastics  materials  who  will  make  the 
trip  to  Chicago  from  all  over  the  country.  All  they  are 
interested  in,  is  seeing  everything  the  plastics  world 
has  to  offer,  and  in  seeing  it  all  at  one  time.  It  is  there- 
fore up  to  the  industry  to  resolve  its  own  dilemma. 

This  is  not  easy.  Enormous  prestige  attaches  to  such 
an  exposition,  and  there  is  also  the  important  fact  that 
it  can  be  profitable.  Thus,  the  stakes  are  high,  and  it  is 
to  nobody's  discredit  that  a  rivalry  should  have  arisen 
virtually  accidentally,  due  to  the  war  situation  and  the 
lack  of  integration  in  our  youthful  industry.  If  there 
is  no  question  of  blame,  the  fact  remains  that  it  is  to 
the  best  interests  of  the  industry  that  there  be  a  single 
exposition.  A  compromise  seems  to  be  in  order. 

This  might  well  be  the  occasion,  at  the  same  time,  to 
effect  a  complete  understanding  as  to  the  differentiation 
of  function  of  the  two  societies.  A  basic  agreement  al- 
ready exists — that  the  SPE  is  an  organization  of  pro- 
fessional men,  as  individuals,  corresponding  to  the 
Society  of  Automotive  Engineers,  while  the  SPI  is  a 
management  group,  with  membership  open  to  companies 
rather  than  individuals,  corresponding  to  the  Automo- 
bile Manufacturers  Association. 

Nevertheless,  in  practice,  due  to  the  rapid  war-time 
growth  of  both  the  societies  and  the  industry,  there  has 
been  considerable  overlapping  of  function.  The  threat 
of  a  dual  exposition  is  only  the  most  critical  example 
of  it.  But  in  bringing  matters  to  a  head,  it  may  pave 
the  way  to  a  clear-cut  resolution  of  the  entire  situation. 
That,  in  our  opinion  and  in  the  judgment  of  most  well- 
wishers  of  the  industry,  is  exactly  what  is  necessary  if 
both  organizations  are  to  offer  the  industry  they  repre- 
sent  tin-  IM-.I  iii  e\er>  thing  it  deserves  and  has  earned. 

'Hie  industry  is  entitled  to  a  fair  shake,  and  there  is 
no  real  good  sound  reason  why  it  should  not  get  it,  HIM 
as  other  great  industries  d<>  from  their  technical  and 


trade  associations  which  have  learned  how  to  function 

without  encroaching  on  one  another's  territory. 

*  *     * 

THE  SUMMER  season  is  over,  and  the  fall  season  is  on. 
In  the  plastics  business,  that  means  something  new 
every  day.  If  there  isn't  a  local  SPI  meeting,  there's 
a  local  SPE  meeting;  if  the  SPE  engine  is  idling,  the 
Plastics  Club  is  carrying  on.  If  it's  none  of  these,  some 
manufacturer  is  staging  a  first  public  showing  of  his 
product.  All  this  keeps  us  plastics  journalists  hopping 

— and  we  love  it ! 

*  *     * 

WE'RE  pleased  to  find  some  of  the  major  plastics 
trade-names  getting  into  the  newspapers  in  a 
free-and-easy  way  which  suggests  that  the  reader  is 
perfectly  familiar  with  them.  Right  on  page  one  of  the 
New  York  Times'  account  of  the  rescue  of  the  passen- 
gers on  the  Belgian  airliner  which  recently  crashed  at 
Gander,  Newfoundland,  was  a  reference  to  "a  stretcher 
carrying  one  of  the  survivors  was  lifted  gingerly  into 
the  Plexiglas  nose  of  the  (rescuing)  helicopter.  .  .  ." 
In  the  Times,  the  name  was  not  even  printed  with  a 
capital  "p"  and  in  italics,  which  is  our  style,  but  in  plain 
upper  and  lower  case  type  like  the  rest  of  the  text. 
Also,  it  was  spelled  with  two  s's ;  but  then,  there  are  a 
lot  of  people  in  the  trade  who  make  that  mistake,  too. 

*  *     * 

IN  CONNECTION  with  the  wave  of  labor  strikes  now 
sweeping  the  country,  it  seems  to  us  that  much  of 
the  trouble  and  the  long  and  costly  process  of  litigation 
could  probably  be  avoided  if  the  provisions  of  labor 
contracts  were  not  so  ambiguously  worded  or  altogether 
silent  on  some  points,  but  were  carefully  phrased  to 
meet  all  contingencies. 

In  an  effort  to  offer  helpful  assistance  in  drafting  a 
contractual  provision  in  future  lalx»r-capital  negotia- 
tions, the  Society  of  the  Plastics  Industry  offers  a 
Model  Clause  concerning  Sunday  and  holiday  over- 
time pay,  to  be  incorporated  in  every  contract.  This 
contains  a  specific  listing  of  holidays  observed  by  the 
company;  whether  or  not  regular  compensation  is  to 
be  made  on  those  dates ;  rate  of  overtime  compensation ; 
payment  for  holidays  when  the  employee  is  aliment  oil 
the  preceding  day;  and  several  other  factors  in  the 
matter  of  holiday  pay  where  controversy  could  arise. 

Such  a  clause  is  certainly  worthy  of  study,  and  in- 
clusion of  similar  articles  in  contracts  would  do  much 
toward  promoting  more  peaceful  relationships  between 
labor  and  capital,  with  business  on  a  happier  and  more 
profitable  scale,  by  letting  each  -ide  know  beforehand 
•ly  where  they  stand  concerning  all  possible  pn>b- 
lems  and  differences  which  might  il 


12 


I*  I.  1ST  1 1  S 


MM  I  MHKR   1946 


How  to  Tune  in 
on  Cost  Cuts! 


Molded  plastic  knobs  and  dials  for  radio — common  now,  but 
not  when  we  introduced  the  first  complete  line  of  stock  parts  back 
in  1922.  Here's  another  Kurz-Kasch  "first"  that  paid  off! 


E, 


VERYBODY'S  shortcut  to  the  production  economies  of  to- 
morrow is  somebody's  pet  bright  idea  today.  There's  a  time  lag  before 
that  idea  gets  around.  Meanwhile,  if  you're  the  lucky  customer  of  the 
originating  molder,  look  at  the  pretty  competitive  position  you'll  be  in! 

\  We've  done  this  for  Kurz-Kasch  customers  time  and  time  again— and 
e're  resolved  to  keep  on  doing  it,  as  our  past  and  present  performance 
light  suggest.  So  let's  get  acquainted.  Send  for  your  copy  of  our  free 
llustrated  booklet,  "A  Businessman's  Guide  to  the  Molding  of 
lastics"— on  your  letterhead,  please. 

Kurz-Kasch 


For  Over  29  Years 

Planners  and  Molders  in  Plastics 


Kurz-Kasch,  Inc.,   1413  S.  Broadway,  Dayton  1,  Ohio.  Export  Offices:  89  Broad  Street,  New  York,  N.  Y. 
Branch  Sales  Offices:  New  York  •  Chicago  •  Detroit  •  Los  Angeles  •  Dallas  •  St.  Louis  •  Toronto,  Canada. 


)VEMBER  1946 


PLASTICS 


13 


RIGHT! 


of  nei  MACNINII  o«  miasreiAi  i«ui««irr 


MT..OOM  fllTIMK  V^,  MIOKM. 


Looking  at  these  refrigerator  defrosting  frays  you  see  an  Amos 
job  as  it  comes  from  the  molding  machine— before  the  sprue 
is  removed— and  the  finished  product  .  .  .  done  exactly  right! 

The  material  is  non-shattering,  clear  polystyrene,  accepted  by 
the  refrigerator  industry  for  its  resistance  to  cold  and  moisture. 
This  is  an  interesting  example  of  Amos  quality  control  in 
plastic  parts  production.  Here  is  accuracy  in  mold-making, 
dose  supervision  in  finishing,  economy  at  every  step. 
Your  own  plastic  parts  or  products  will  receive  the  same 
interested  attention  in  the  fully-equipped  and  capably-staffed 
Amos  plant.  Your  product  reputation  is  in  good  hands  at 
Amos.  Just  send  your  drawings  or  write  us  what  you  have  in 
mind.  Amos  will  do  it ...  right! 

AMOS    MOLDED    PLASTICS    •    EDINBURGH,    INDIANA 

Divltion  of  Amot-ThompKX!  Corpof  olk>« 

oitic  Molding  Plants  in  fh«  /noWry 


14 


I'LASTtCS 


\{}\  KM  HK  It    1!'H 


Section  of  display  mockup  built 
by  Douglas  Aircraft  offers  view 
of  interior  of  the  DC-6  "Sleep- 
er" which  utilizes  a  variety  of 
plastics  in  its  cabin  fittings.  The 
United  Air  Lines  and  other  trans- 
port companies  will  probably 
adopt  this  design  in  future  models 


Plastics  Dominate  JVew 


Prime  requirements  for  wearability,  ease  of  maintenance,  fire 
resistance,  are  fulfilled  by  application  of  plastics  materials 


<7 


C.  CL 


oSe 


INDUSTRIAL  designers  and  engineers  responsible  for 
the  interior  cabin  fittings  of  the  new  Douglas  DC-6 
Sleeper  airplane  used  good  logic  in  selecting  plastics  ma- 
terials, which,  according  to  E.  Gilbert  Mason,  industrial  de- 
sign consultant,  were  chosen  only  when  it  was  felt  that  they 
would  serve  better  than  any  other  materials  available.  There 
are  more  than  1,000  separate  plastics  pieces  on  this  new 
plane  in  approximately  300  different  kinds  of  parts. 

When  a  plastics  material  was  considered,  it  had  to  meet 
three  prime  requirements — wearability,  fire  resistance,  and 
ease  of  maintenance.  This  is  a  complete  departure  from  the 
general  idea  that  plastics  are  used  because  they  are  light  and 
cheap.  Despite  the  rigid  yardsticks  determining  acceptance, 
the  number  of  plastics  applications  in  the  DC-6  cabin  in- 
terior is  most  extensive. 

Floor  covering  in  the  combination  entrance-buffet,  on 
the  flight  deck,  and  in  the  forward  and  aft  lounge  sections, 

Acrylic  partitions  dividing  lounge  from  cabin  area  add  a 
feeling  of  spaciousness;  table  tops  are  melamine  laminates 

NOVEMBER  Iftdfi  is 


Luxurious  lounges,  a  feature  of  the  new  DC-6.  are  effi- 
ciently planned  to  offer  the  utmost  in  comfort.  Right, 
view  of  deluxe  galley  facilities.  Sidewall  and  ceiling 
coverings  are  of  stretched  vinyl  coated  fabrics  embossed 
and  colored  to  match  color  schemes.  Methyl  methacryl- 
ate«  are  used  for  double  pane  windows  and  light  shield 


is  vinyl  chloride  calendered  sheet  laminated  integrally  with 
a  Yt,"  foam  rubber  backing.  The  covering  is  anchored  to  the 
floor  with  mastic  adhesive.  Douglas  will  provide  this  ma- 
terial in  any  color  desired,  and  with  a  finish  which  simulates 
a  "pebbled"  carpet.  Cushioning  effects  of  the  foam  rubber 
backing  increase  the  illusion  of  high-grade  worsted  carpet- 
ing material.  It  is  long-wearing,  scuff-and-fire-resistant,  and 
easily  cleaned.  An  extruded  vinyl  base  molding  is  employed 
to  fair  the  floor  covering  with  the  sidewalls  of  the  cahin. 
Here,  also,  the  quality  of  scuff-resistance  prompted  selection 
of  this  material. 

Cabin  wainscoting  material  from  floor  to  window  sill 
is  a  vinyl-coated  fabric  with  an  embossed  grain  effect. 
Papreg,  a  high-strength  phenolic-impregnated  paper  lami- 
nate, serves  as  backing  for  the  wainscot,  and  forms  a  hot 
air  duct  leading  from  floor  to  window  level.  Vinyl-coated 
fabric  is  used  in  many  other  cabin  applications,  including 
overall  wall  and  ceiling  coverings  for  both  lounge  sections 
and  for  the  entrance-buffet  section,  covering  for  the  seat 
fairings,  for  curtains,  berth  ladder  steps,  and  others.  Ease 
of  maintenance,  in  that  the  vinyl  material  can  be  washed 
without  removal  from  the  airplane,  its  fire-resistance,  wear- 
ability,  and  the  fact  that  it  can  be  produced  in  any  desired 
color,  and  with  various  decorative  effects,  were  factors  re- 
sponsible for  the  numerous  applications. 

AII-Platt!c*  Windows 

Windows  of  the  airliner,  both  panes  and  frames,  are  of 
plastics  materials.  The  frames  arc  constructed  using  ESES 
(pronounced  "essess")  Hardboard,  a  hard  rubber -like  ma- 
trrial  with  a  low  degree  of  thermal  conductivity  and  very 
good  forming  characteristics.  This  material  can  be  o>m 
pounded  in  the  colors  necessary  to  conform  with  any  de- 
sired cahin  color  layout.  It  has  high  insulation  value,  both 
for  sound-proofing  and  for  temperature  differentials.  The 
double  window  panes  are  of  transparent  acrylic,  spaced  ap- 
proximately Vt."  apart  and  hermetically  scaled  with  acrylic 
edge  strip-,  cemented  in  place.  Construction  of  the  pane 
prevents  fogging,  and  at  the  same  time  provides  ample 
strength  for  cahin  pressurizing. 

The  panels  separating  the  club  lounge  and  main  cabin 
areas  are  constructed  either  of  impregnated  plywood  or 
transparent  acrylic,  at  may  be  required.  The  transpaimt 
panels  lend  xparioiisness  to  the  cabin  interior — a  p-yrlio 
loirieally  advantageous  factor  in  minimi/ing  the  tcdioii>nes- 
of  !"iic  \- 


Aside  from  basic  constructional  employment,  plastics  ;ire 
used  for  many  of  the  cabin  fittings  and  conveniences.  In- 
direct cabin  lighting  is  furnished  by  means  of  an  inverted 
l'--haped  Fiberglas-doth  light  trough  with  incurled  edges, 
behind  which  light  sources  are  concealed,  so  that  light  rt-arh- 
ing  the  cabin  is  reflected  from  the  cream-white  trough  in- 
terior. The  trough  edges  are  transparent,  and  covered  by  an 
extension  of  the  ceiling  fabric,  blending  it  translucently  \\  ith 
the  source  of  illumination. 

All  other  lights,  including  individual  seat  lights,  berth 
lights  and  lounge  lights,  are  of  plastics  construction,  utiliz- 


Innovalions    are    these    acrylic    coat    hangers    with    com- 
pany name  plate,  and  transparent  plastics  magazine  racks 


16 


NOVKMIIKR   1946 


ing  acrylic  globes.  They  are  carefully  spaced  to  provide  local 
illumination  without  bothering  other  passengers. 

Seats  and  berths  are  provided  with  plastics  compartments 
to  hold  literature,  makeup  or  shaving  kits,  and  other  acces- 
sories. Most  of  these  compartments  are  equipped  with  a 
transparent  vinyl  cover,  making  it  possible  to  see  what  is  in 
the  compartment  and  avoid  leaving  personal  belongings  be- 
hind. The  main  literature  rack,  available  to  all  passengers, 
is  of  Papreg  construction  with  cast  acrylic  magazine  pocket 
covers  for  easy  identification  of  the  contents. 

Stewardess  call-buttons,  seat  incline-control  buttons,  and 
other  passenger-convenience  buttons  are  either  of  cast 


phenolic  or  molded  melamine.  Garment  hangers  are  of  trans- 
parent acrylic  embossed  with  the  name  of  the  airline.  The 
control-buttons  in  the  lavatories  are  a  newly  developed  prod- 
uct, made  of  a  translucent  acrylic  material  and  identified  by 
a  flush-type  colored  inlay.  Considerable  research  was  neces- 
sary before  the  color  inlay  feature  could  be  used,  as  there 
was  a  tendency  for  the  color  to  diffuse  into  the  translucent 
body  of  the  button. 

Mirrors  are  of  acrylic,  and  vary  in  size  from  full-length 
to  the  small  makeup  mirrors  in  each  berth.   Table  tops  used 
in  the  club  lounge  sections  are  of  Formica-type  laminate, 
(Continued  on  page  75) 


Comfortable  berths  in  air-conditioned  cabins  provide 
additional  conveniences  in  the  form  of  plastics  van- 
ity kits  with  acrylic  mirrors,  and  transparent  vinyl 
pockets.  Below,  all  the  comforts  of  home  are  offered 
to  the  present-day  air  traveler.  The  lounges  use  a 
variety  of  plastics  materials  for  various  applications 


"Topping" 
Vinyl  Sheet 

mi 


Snakeskin  and  alligator  finishes,  made  possible 
by  new  method  of  topping  vinyl  sheet,  compare 
favorably  with  genuine  snakeskin.  The  handbag 
shown  is  sold  at  the  loan  Barrie  store.  New  York 


ANEW  method  of  topping  vinyl  sheet  which  mechan- 
izes a  hitherto  hand-dominated  procedure  has  been 
developed  by  Martin  Silverman,  president  of  the  Plastic 
Printing  Corporation,  of  Brooklyn,  N.  Y.,  with  the  co- 
operation of  the  Aridye  Corporation,  of  Fairlawn,  N.  J. 
Entirely  automatic  from  feed  to  finish,  the  new  process  has 
greatly  increased  the  production  rate  for  this  type  of  print- 
ing on  vinyl  and  has,  at  the  same  time,  effected  an  improve- 
ment in  quality. 

Strictly  speaking,  and  as  used  in  this  discussion,  "topping" 
is  the  application  of  color  and  finish  on  vinyl  sheet.  Print- 
ing on  thin  vinyl  film  (in  the  popular  4-gauge,  for  example) 
has  already  been  made  automatic  in  several  processes — 
roller  printing  among  them — but  printing  on  heavy  sheet, 
notably  18  to  22  gauge,  which  has  been  in  demand  for  a 
multitude  of  applications,  has  presented  a  number  of  prob- 
lems that  have  caused  production  to  be  confined  to  largely 
manual  procedures.  The  two  most  prevalent  of  these  are 
spraying  and  spongeing  or  wiping. 

The  completely  automatic  process  adopted  at  the  Plastic 
Printing  Corporation  plant  reduces  manual  operations  to 
mounting  the  feed-roll  and  demounting  the  rewind-roll. 
The  production  rate  difference  between  this  method  and  tin- 
older  ones  may  be  gleaned  from  the  fact  that,  with  spraying, 
it  takes  1  hr  to  top  a  50  yd  roll  of  36"  width,  whereas  the 
new  method  does  the  same  job  in  7  min. 

In  current  processes,  there  are  intermittent  halts  in  opera- 
tion to  permit  time  for  drying  of  the  ink,  usually  through 
oxidation.  In  the  new  method,  drying  takes  place  rapidly 
enough  to  permit  a  multi-color  job  to  be  fed  directly  and 
continuously  through  successive  print  rollers.  A  new  fast- 
drying  ink  developed  for  the  purpose  by  Aridye  is  mainly 
responsible  for  this.  It  consists  of  a  dispersion  of  specially 


pigment  colors  in  an  organic  solvent  solution  of  a 
copolymer  of  vinyl  chloride  and  vinyl  acetate.     A  special 
dulling  ink  has  also  been  formulated  to  provide  a  matte 
finish,  which  is  in  strong  demand  for  many  application- 
Adhesion  of  ink  to  sheet  achieved  by  the  new  process  i| 
high.     There  is  apparently  considerable  penetration,  for  a 
(Continued  on  page  75) 


18 


/'  /    t 


Dark  back  side  shows  through  on  surface  ol  "topped"  strip 
STH'S  NOVKMKKR   194 


• 


A  new 
hookup  with 

TENITE 


1  his  popular-priced  crystal  microphone 
housing  is  just  one  of  the  many  new  postwar 
products  that  have  been  made  more  durable, 
practical,  and  attractive  with  Tenite. 

The  sturdy  Tenite  case  is  built  to  stand  up 
under  the  hard  wear  of  home -recording  and 
public-address  use.  Since  Tenite  is  light  in 
weight,  the  microphone  is  easily  used  as  a 
hand  model,  as  well  as  on  desk  or  table.  The 
gray  color  (matched  perfectly  to  the  designer's 
specifications)  can't  chip  or  peel,  because  it 
goes  all  the  way  through  the  plastic.  A  whisk 
of  a  damp  cloth  is  sufficient  to  clean  the 
smooth,  pleasant-to-touch  Tenite  surface. 

Tenite  can  be  molded  at  the  fastest  speed 
possible  with  plastics — thereby  greatly  help- 
ing to  increase  production  and  cut  costs  in 
the  manufacture  of  many  articles.  Finishing 
operations  are  reduced  to  a  minimum,  since 
a  high  natural  luster  is  imparted  to  Tenite 
from  the  polished  molds. 

Investigate  the  possibility  of  molding 
or  extruding  your  product  of  Tenite.  For 
complete  information,  write  to  TENNESSEE 
EASTMAN  CORPORATION  (Subsidiary  of 
Eastman  Kodak  Co.),  KINGSPORT,  TENN. 


Tenite  cases  for  Comet  microphones  are  molded  by  Sobenite,  Inc.,  for  Electro -f'oice.  Inc. 


TENITE 


AN  EASTMAN  PLASTIC 


Laminating  for 
Glare-Proof  Surfaces 

New  finish  for  cellulose  acetate  sheets  eliminates  surface  reflection, 
thus  permitting  clear  view  of  laminated  object  and  relieving  eyestrain 


Laminated  tags  are  removed  from  the  press  and  separated 
with    a    paper    cutter    prior    to    die-cutting    in    oval    shape 


<2).  St 


ilk 


A  sh»«t  of  celluloee  acetate  i»  placed  over  credit  caidi 
which  are  spaced  evenly  apart,  preparatory  to  laminating 


rait  on 


POSSIBILITIES  for  the  gift  and  art  fields  are  presented] 
in  photographs  and  art  prints  laminated  in  cellulose] 
acetate  sheets  with  a  non-reflecting  surface.  By  eliminating] 
halation,  the  photos  and  prints  can  be  seen  without  di-tor- 
ticm.  from  any  angle,  and  the  appearance  not  only  of  these, 
but  also  of  water  colors  and  charcoal,  chalk  and  ci 
drawings,  is  greatly  enhanced.  Their  protection  from  wrin- 
kling, cracking,  folding,  blurring,  or  moisture-absorption  is 
another  important  feature  provided  by  this  method. 

A  number  of  applications  of  this  finish  have  been  made  at 
Kirk  Plastic  Co.,  Los  Angeles,  which  for  years  has  special- 
ized in  sandwiching  papers  of  various  sorts  between  cellul<  ^e 
sheets  with  glossy  surface.  Since  beginning  exploration  of] 
possibilities  of  the  non-glare  surface,  however,  this  method] 
has  been  used  for  many  laminated  paper  or  cloth  items,! 
other  than  pictures,  which  require  a  non-reflecting  surface. 

Various  office  forms,  particularly  those  to  which  frequent 
reference  must  be  made,  have  received  this  treatment,  which 
eliminates  eyestrain  to  such  degree  that  clerks  have  !•<•< -n 
enabled  to  speed  up  their  work  to  a  great  extent.  Forms  fof 
which  this  finish  has  proved  effective  include  statistical 
graphs  and  tables,  such  as  withholding  and  sales  tax  charts. 
Protection  from  excessive  handling  has  thereby  been  af- 
forded the  printed  paper  within  the  sandwich,  and  its 
readability  has  been  considerably  improved. 

As  the  surface  of  this  laminate  is  microscopically  rotiu'h 
and  irregular,  it  lends  itself  to  marking  by  lead  pencil :  tln>e 
marks  may  be  quickly  and  easily  removed  with  an  ordinary 
eraser. 

Used  Like  Slate 

This  type  of  lamination  has  accordingly  been  used  in 
xi  ime what  the  same  manner  as  a  slate.    When  the  sheet  has 
been  filled  with  writing  it  is  cleared  with  an  eraser,  and  is 
then  ready  for  another  notation.     Because  of  this  char- 
acteristic, the  non-glare  surface  has  been  applied  to  lamina- 
tions of  daily  appointment  memos.  daily  production  r< 
and  blanks  on  which  hotel  telephone  operators  nighth 
the  hour-  to  awaken  guests  on  the  following  morning. 

Moisture-resistant    characteristics    of    this    lamination 
coupled  with  its  slatelike  writing  surface,  prompted  tli> 
Angeles  Flood  Control  District  to  use  large  quant  ii 
printed  form-,  treated  by  the  process.     Its  engineers  carry 
these   laminated   blanks   when   making   inspection--,   which 
frequently  take  place  during  heavy  dii\ui|Hiiirs  of  rain.      1  lie 
department  no  longer  need  contend  with  water 
ports,  and  after  the  information  contained  on  the  laminated 
forms  has  been  cnpied  for  tiling,  the  same  forms  arc  «•!• 
of  pencil  marks  and  are  reissued  to  held  engineets  sim-i-  this 
type  of  record  can  be  used  repeatedly  without  deteriorating; 

Some  progress  also  has  been  made  in  laminating  filmy 
fabric,  and  sili  i  or  printed  ( >//of/i<jn.-.  ln-twecn 

cellulose  a-  .-els  for  lamp  shade  material.    The  non- 


PI.. \srirti 


M>\  KMKKR   1946 


Completed  sandwich  being  loaded  into  one  of  five  open- 
ings of  hydraulic  laminating  press  used  at   Kirk   plant 


Operators  align  laminated  badges  on  chain  belt  leading 
to   die   cutter,   where   an   electric    solenoid   trips   the    die 


glare  finish  is  applied  to  the  surface  designed  for  the  inner 
part  of  the  shade,  with  a  high  gloss  for  the  outer  surface. 

The  frosted  effect  on  the  interior  diffuses  illumination  and 
provides  a  soft  backlighting  which  enhances  the  design  and 
color  of  the  material  used  as  the  inner  ply. 

Kirk  achieves  its  non-glare  surfaces  by  using  a  chrome 
steel  plate,  in  which  minute  pits  are  formed  by  nitric  acid 
in  the  manner  in  which  a  steel  engraving  is  made.  This 
plate  is  placed  in  the  laminating  press  against  the  cellulose 
acetate  sheet,  upon  which  each  microscopic  crater  rim  em- 
bosses itself,  establishing  a  surface  which  cannot  produce 
annoying  light  reflection. 

Another  type  of  non-glare  surface  is  established  by  insert- 
ing a  sheet  of  fabric  between  the  cellulose  acetate  and  the 
usual  smooth  chrome  steel  plate  used  in  laminating.  The 
weave  of  the  cloth  is  then  pressed  into  the  heated  thermo- 
plastic material. 

Chintz,  cretonne,  or  inexpensive  cotton  dress  goods  are 
particularly  effective  for  this  purpose.  Silks  and  satins,  being 
more  closely  woven,  create  scarcely  noticeable  impressions. 
Low  priced  grades  of  cloth  are  generally  used,  as  the  same 
piece  of  fabric  seldom  can  be  applied  satisfactorily  for  more 
than  two  laminations.  The  pressure  and  heat  flatten  the 
weave  to  such  extent  that  it  can  no  longer  impress  its  outline 
upon  the  cellulose  acetate.  New  pieces  of  fabric  are  therefore 
constantly  being  used  as  replacements. 

Less  suitable  for  laminations  of  paper  where  high  read- 
ability is  essential,  the  fabric-like  surface  has  been  used 
mainly  when  sandwiching  prints  for  book  and  menu  covers. 
The  impression  of  the  criss-cross  weave  is  pleasing  to  the 
touch  and  provides  an  artistic  effect. 

The  same  fabric-like  surface  on  cellulose  acetate  sheets 
has  proved  helpful  in  establishing  bonds  with  textiles  or 
woods,  as  glue  and  cement  will  adhere  to  the  criss-cross 
indentations.  The  practice  has  been  utilized  to  fabricate 
book  covers  when  velour  or  plush  was  to  be  cemented  to  a 
cellulose  acetate  backing.  It  also  has  been  applied  when  the 
thermoplastic  sheets  were  to  be  bonded  to  wood  blocks,  as  in 
packaging  devices  or  novelty  merchandise. 

While  laminations  in  which  paper  is  the  central  ply  of  the 
three-piece  sandwich  have  progressed  for  nearly  two  decades 
at  Kirk's,  the  greatest  strides  in  new  developments  have  been 
made  in  the  past  two  years. 

One  of  the  largest  production  fields  in  which  non-glare, 


fabric-impressed  or  gloss  surfaces  have  recently  been  used, 
is  in  laminating  cellulose  acetate  menus.  The  change  from 
the  frequently  grease-spotted,  finger-marked  bill  of  fare 
formerly  found  in  some  restaurants,  with  its  frayed  edges 
and  bent  corners,  has  been  a  welcome  one  to  diners.  And 
when  one  considers  the  OPA  estimate  of  25,000,000,000 
restaurant  meals  served  in  this  country  during  the  year  of 
1945  alone,  the  importance  of  menus  that  will  endure  the 
impact  and  stress  of  restaurant  handling  becomes  notable. 

Laminations  of  printed  paper  between  transparent  cellu- 
lose acetate  sheets  also  have  been  employed  for  travel  books, 
catalogs,  sample  kits,  sales  campaign  folders  and  numerous 
other  items  of  comparable  size.  Similarly,  they  have  been 
utilized  in  production  of  such  smaller  pieces  as  business 
cards,  plant  workers'  badges,  hotel  and  pocket  key  tags, 
credit  cards,  price  markers  and  lodge  identifications. 

The  process  may  be  applied  to  advantage  wherever  per- 
manency, cleanability,  neatness,  resistance  to  grease  absorp- 
tion, and  high  optical  qualities  are  essential.  Clearness  of 
the  cellulose  acetate  sheets  and  the  true  images  which  they 
render  to  the  eye  make  the  lamination  as  easily  readable  as 
was  the  page  when  it  came  from  the  printing  press. 

Cellulose  nitrate  sheets  were  originally  used  in  this  field, 
but  some  time  ago  the  firm  switched  mainly  to  acetates ;  it 
now  utilizes  Monsanto's  Vuepak  or  Eastman's  Kodapak  for 
most  of  its  purposes. 

Flexible  and  Adherent  Qualities 

These  transparent  thermoplastic  sheets  possess  high  flex- 
ibility and  will  adhere  under  heat  and  pressure,  without 
cement.  Their  weight  is  light;  usually  .005"  sheets  are 
used,  making  a  lamination  of  .010"  thickness  plus  the  thick- 
ness of  the  compressed  internal  layer  of  printed  paper. 

Operations  of  this  type  are  performed  in  a  hydraulic 
press  which  exerts  750  to  850  psi.  The  heating  and  cooling 
cycle  is  approximately  12  min.  A  heat  of  275°  F  is  built  up 
in  approximately  5  min  by  circulation  of  steam  through  the 
press  platens.  When  this  heat  has  been  registered  by  the 
pyrometer,  the  steam  is  cut  and  cold  water  is  circulated 
through  the  platens  to  accelerate  cooling. 

Despite  these  general  practices,  it  is  customary  to  make 
several  trial  runs  to  determine  the  maximum  heat  which 
paper  and  ink  will  bear  in  the  specific  operation  without 
deteriorating. 


NOVEMBER  1946 


PLASTICS 


21 


Wooden  clothespins  clamp  sheet  acetate  overlays  as  pins 
arc  affixed  with  acetone  application  to  employee  badges 


The  press  used  at  Kirk's  has  five  openings,  all  handling 
24"  by  26"  laminations.  Frequently,  five  sandwiches  are 
placed  in  an  opening.  Loaded  to  capacity,  the  press  per- 
forms 25  laminations  in  a  12  min  cycle.  As  3  min  is  the 
usual  time  allowed  for  unloading  and  loading,  the  press  is 
capable  of  four  cycles  an  hour.  Four  to  twelve  workers  are 
required  to  prepare  the  sandwiches,  the  number  depending 
on  whether  small  or  large  items  are  being  fabricated. 

Regardless  of  their  size,  the  printed  paper  sheets  are  laid 
end  to  end  and  side  by  side  between  acetate  sheets  as  large 
as  the  press  will  accommodate.  The  paper  sheets  are  spaced 
sufficiently  apart  to  leave  suitable  margins  when  cut.  At 
least  1/16"  margins  should  be  allowed  to  effect  the  neces- 
sary edge  seal  and  to  present  the  best  appearance. 

Each  sandwich  is  pressed  between  chrome  steel  plates 
which  must  be  free  of  scratches  or  other  surface  impairment. 
The  steel  plates  are  in  direct  contact  with  the  cellulose  ace- 
tate, and  any  imperfections  in  their  surfaces  will  be  em- 
bossed on  the  product. 

On  both  sides  of  the  steel  plates,  three  layers  of  flannel 
padding  or  two  sheets  of  ordinary  blotting  paper  are  placed, 
to  distribute  the  pressure.  Outside  of  these  pads  1/16" 
copper  plates  are  inserted  to  stabilize  the  sandwiches  as 
pressure  is  exerted. 

For  cutting  and  trimming  to  size  after  lamination,  an 
ordinary  30"  straight  edge  paper  knife  of  the  photo-lal>ora 
tory  type  may  be  employed.    But  in  mass  production,  Kirk 
utilizes  a  die-cutting  machine  equipped  with  a   solenoid 
which  trips  the  die  at  the  rate  of  1600  cuts  an  hour.    An 
applicatii.n  of  acetone  to  the  transparent  margins  inc- 
their  clarity  and  smoothes  their  trimmed  edges. 

Credit  Cards  Preserved 

( )il  company  credit  cards  make  up  a  large  volume  in  this 
type  of  priHlm-tiiin.  Although  thrxc  arc  carried  on  the  per- 
son for  a  year  at  a  time  they  arc-  in  virtually  as  good  cmuli- 
tion  at  the  end  of  the  year  as  when  issued. 

Sonic  items  require  heavier  protecting  material.  I  or 
hotel  key  tag*  .030"  thick  cellulose  acetate  sheets  are  sand 
wichcd  on  either  side  of  printed  cards.  Cost  of  the  acetate 
key  tag  i»  approxinwtely  three  time*  that  of  the  old  red 
pressed  fibre.  Rut  it  continues  in  service  indefinitely,  and 
•lot  brtvl.  buckle  or  split  like  its  tibrc  predecessor.  It 


moisture  absorption,  and  when  scratched,  or  showing 
signs  of  use,  it  is  customary  with  hotels  to  dip  the  tags  ir 
acetone,  which  restores  the  original  lustre  and  clarity.  Too 
checks,  baggage  and  camera  tags  and  identifying  plates  foi 
machinery  are  fabricated  with  .005",  .01 5"  and  .030"  plastics 
Photos  are  sometimes  overlaid  on  the  printed  paper  be 
neath  the  thermoplastic  sheet.  They  may  be  affixed  will 
rubber  cement,  \\hich  vulcanizes  under  the  heat  and  pre^un 
oi  the  lamination.  Ordinary  library  paste  and  F.astman'; 
dry  mounting  tissue  also  serve  as  adhesives  for  this  purpose 
Certain  glues  tend  to  discolor  the  photo. 

Tamper-Proof  Badges 

B.  L.  Hyde,  owner  and  general  manager  of  Kirk's,  state: 
that  Douglas  Aircraft  Co.  during  the  war  ordered  250,00( 
tamper-proof  badges  for  workers.  To  facilitate  production 
450,000  detachable  sections  held  by  interlocking  rivets  wen 
required. 

By  means  of  the  detachable  sections  one  badge  replace< 
240  types  previously  used.  Workers  retained  their  origina 
time-clock  numbers,  imprinted  on  their  badges,  when  shift 
ed  from  one  department  to  another.  Their  change  in  wor 
classification  necessitated  merely  a  removal  of  the  detach 
able  section  and  its  substitution  with  another. 

Ran  Miller,  Kirk's  industrial  designer,  estimated  Doug 
las  saved  $250,000  a  year  through  this  economy.  \Vhil< 
prices  vary  for  different  operations,  employee  badges  wit: 
detachable  sections  are  fabricated  at  an  average  price  of  25 
a  unit. 

As  with  most  of  such  laminations,  acetone  is  usually  ap 
plied  to  edges  of  employee  badges  after  trimming.  Saddle 
back  pins  are  affixed  with  a  sheet  acetate  overlay  to  whic 
the  same  solvent  has  been  applied. 

Moisture-and-oil-resistant  laminated  price  tags  for  foo 
stores  and  meat  markets  are  fabricated  with  one  .015"  print 
ed  cellulose  acetate  ply,  the  inked  side  of  which  is  ovcrlaii 
with  a  sheet  of  .0088"  Cellophane.  In  use,  these  are  thrus 
upright  in  cottage  cheese,  wet  salads  or  ground  meats.  Hyd 
points  out  that  the  Cellophane  sheet  complies  with  pure  foo 
laws  of  many  communities  as  it  seals  the  ink  from  contac 
with  edibles. 

Changeable  price  numerals,  similarly  laminated,  ar 
slipped  under  punched-up  points  in  the  acetate-CYMo/>fom 
piece  to  enable  the  market  operator  to  keep  abreast  of  vary 
ing  market  quotations.  Heat  and  pressure  in  sandwichin 
Cellophane  to  printed  acetate  are  approximately  the  same  a 
those  used  in  the  acetate-paper  lamination. 

Heavier  Laminations 

i  onim'nations  of  paper  and  acetate  may  be  built  to  grca 
thickness  and  stiffness  by  using  heavier  acetate  sheets  or  b 
increasing  the  number  of  acetate  layers.  Cellulose  acctat 
sheets  adhere  to  each  other  under  this  treatment,  as  they  d 
to  printed  paper  or  cardboard.  With  these  thicker  lamina 
tions,  interesting  third  dimensional  optical  effects  may  b 
achieved. 

One  of  the  heaviest  of  these  jobs  \\:is  the  fabrication  o 
dials  for  ship  signal  systems.  Sheets  .O1'"  thick  were  use 
to  produce  a  lamination  more  than  .18"  thick.  To  exclud 
moisture  and  salt  spray,  clear  plastics  edges  of  considcrahl 
uidth  were  left  around  holes  for  brackets  and  gage  pinion 
ami  around  the  outer  margins. 

Such  gages  have  clear  optical  properties  and  their  thir 
dimensional  effect  gives  an  illusion  of  greater  thirknesr 
Miller  said  that  tests  under  different  lighting  condition 
proved  them  more  easily  readable  than  metal  ones  in  ever 
instance.  They  also  have  the  advantage  of  being  cleanabl 
with  soap  and  water.  Polishing,  required  for  bra 
eliminated. 

Printed    cotton    fabrics,    sheer    materials,    chintzes    an 
rayons  sometimes  may  be  laminated  without  fading  at  heat 
••:ntn,-<i  .'»  f-iin. 


mm 


ri.  \srit  s 


PLASTICS  INJECTION  PRESSES 

offer  these  advantages  •  Economical  Produc- 
tion •  Versatile  Performance  •  Simplified 
Operation  •  Lower  Mold  Costs  •  Low  Orig- 
inal Investment. 

Custom  molders,  manufacturers,  laboratories 
and  schools  are  finding  these  1  02.  molders 
extremely  practical — well  suited  for  a  wide 
range  of  production  and  research  requirements. 


FOR  THESE 
FREE    BULLETINS 

which  illustrate  and  de- 
scribe the  Van  Dorn 
Plastics  Injection  Presses 
and  their  applications. 


2683     EAST    79TH     STREET 


CLEVELAND     4,     O 


NOVEMBER  1946 


PLASTICS 


23 


Accuracy  ol  scale,  authentic!!) 
oi  detail,  weight,  and  elimina 
lion  of  assembly  operations  ii 
production,  were  some  ol  th« 
problems  to  be  studied  in  exe 
cuting  models  of  units  of  c 
cellulose  acetate  toy  trair 
which  is  soon  to  be  placed  or 
market  by  Ardee  Plastics.  Inc 


Models  Aid 
DESIGN 


M.    Kuiin 


6»n.   Mgr.,   Condor   PUittcl   Company 


THE  maker  of  plastics  models  is  being  increasingly 
called  upon  for  services  which,  only  a  short  time  ago, 
were  not  considered  within  the  range  of  his  functions.  This 
is  true  especially  where  the  model  maker  is  a  mold  maker  as 
well.  One  of  the  most  important  of  these  "side  services" 
and  the  one  that  seems  to  be  having  a  particularly  rapid 
development  lies  in  the  field  of  product  design.  That  is. 
normally,  the  function  of  the  plastics  designer  or  the  product 
engineer.  But  the  fact  remains  that  many  a  manufacturer 
of  plastics  items  has  come  to  expect  the  model  maker  not 
only  to  advise  him  on  design,  but  to  redesign  and,  if  neces- 
sary, to  design  from  scratch. 

This  development  has  its  origin  in  the  rapid  increase  in 
the  number  of  manufacturers  of  plastics  items  in  the  l.i-t 
year  or  two.  A  great  number  of  them,  though  by  no  means 
all.  begin  with  limited  financial  means  and,  in  by  far  most 
cases,  of  even  more  limited  knowledge  of  plastics  and 
plastics  processing.  In  any  case,  for  one  reason  or  another, 
many  of  them  tend  to  place  the  design  problem  in  the  lap  of 
the  model  and  mold  maker.  Sinn-  this  trend  may  well  con- 
tinue for  some  time,  it  is  well  for  the  model  maker  to  be 


24 


awake  to  the  situation  and  prepare  to  inert  it.  At  the  saml 
time,  he  will,  in  the  process.  1K.  familiarizing  the  manufac- 
turer with  both  the  pn-sihilities  and  the  limitations  of  pi; 
tics  product  production. 

Four  products  have  Ix-en  selected  for  this  disciis-ion  td 
illustrate  the  design  problem  that  is  presented  to  the  model 
maker  and  the  type  of  information  that  would  he  helpful  id 
providing  the  manufacturer  with  background  km>wl. 
coneeiving  hi^  item  and  planning  for  its  design  and  product] 
lion.  All  of  them  are  brand  new.  Two  are  inst  about  !••  Iw 
marketed,  two  are  still  in  the  premarketing  stage,  l-'.ach  o£ 
them  exemplified  a  different  stage  of  conception  and  desiJ 
at  the  time  the  problem  was  handed  to  us  prepai.it"tv  to 
making  a  model  and  then  a  mold. 

The  first  product^  we  -lull  take  up  are  the  models  of  thj 
locomotive  ami  coal  ear  of  a  cellulose  acetate  toy  train  which 
•lit  to  IK-  placed  on  the  market  by  Ardee  Plastics,  Inc., 
nf  New  York.  Put  l»efore  us  were  certain  definite  require- 
ments rather  than  design  specifications.  These  require1 
meiits  were  that  the  design  be  for  a  train  of  the  period  l')20> 
1930,  that  it  be  to  scale,  that  detail  be  accurate,  that  the  nnitl 


NOVKMHKK   1941 


'The  Outstanding  Development 


FOR  MAKING 


Sealed  Plastic  Product 


LIKE  THESE! 


100%  water-proof,  air-light  plastic  mitten-liner,  THERMATRON- 
sealed  by  Clarvan.  "Enthusiastically  received  .  .  .  constantly 
increasing  sales,"  Clarvan  reports.  Electronically  welded  seams 
eliminate  stitches,  add  strength. 


Plasticoid  Crib  Sheet  with  corners 
electronically  welded  with  THER- 
MATRON. "Ideal  construction  for 
perfect  fit,"  says  Clarvan,  "Dura- 
bility far  superior  to  any  other 
design." 


*R«g.  Trod«  Mark 


Again  a  famous  manufacturer  reports  enthusias- 
tically on  THERMATRON  for  making  water-tight,  air-tight 
seams  on  plastic  products.  Again  this  enthusiasm  is  backed 
up  with  an  order  for  more  THERMATRON  equipment!  Again 
a  story  of  how  THERMATRON  improved  products,  stepped 
up  sales,  PROFITS! 

Investigate  THERMATRON.  You  can  make  seams  in  plastic 
products  strong  as  the  material  itself.  You  can  increase 
product's  tensile  strength,  eliminate  stitching,  adhesives, 
solvents.  You  can  open  up  possibilities  for  hundreds  of  new 
profit-making  plastic  specialties  .  .  .  with  THERMATRON. 

THERMATRON  electronic  sealing  is  the  fast,  modern,  low- 
cost  way  to  seam  handbags,  Cushions,  shower  curtains,  beach 
toys,  raincoats,  shoes  .  .  .  many  other  plastic  products,  too. 

THERMATRON  Dielectric  Heaters,  self-contained  and  ready 
to  use,  are  also  available  to  molders  for  heating  plastic  pre- 
forms, plywood,  rubber,  and  for  general  purpose  use. 

Write  on  your  letterhead  for  your  free  copy  of  "Electronic 
Heating  and  Sealing  With  the  Thermatron."  This  8-page 
bulletin  illustrates  and  describes  in  detail  THERMATRON 
industrial  electronic  heat  generators  for  sealing  and  pre- 
heating. Address  Dept.  T-22 


'•  IB  «Mr*n«*  troii 


DIVISION 


B^       RADIO  RECEPTOR  CO.,  INC. 

Since  1 922  in  Radio  and  Electronics 
251  West  19th  Street 
New  York  11,  N.  Y. 

Midwest  Sales  &  Service:  Zephyr  Electronics,  Chicago 


NOVEMBER  1946 


PLASTtCS 


25 


Several  tricky  problems  were  involved  in  designing  an 
all-plastics  coin-holder  purse.  This  item  is  a  radi- 
cal departure  from  the  usual  zippered  leather  holder 


be  of  a  certain  weight  and  that  no  assembly  operations  be 
involved  in  any  unit  of  the  train. 

Since  the  design  was  left  to  us,  a  certain  amount  of  re- 
search was  necessary,  mainly  a  study  of  drawings  and  pho- 
tographs of  regular  trains  in  use  during  the  specified  period, 
many  of  which,  incidentally,  are  still  operating  today.  The 
design  finally  decided  upon  was  not  a  composite  -of  types, 
but  a  definite  style  of  train  in  use.  A  model  of  cellulose  ace- 
tate was  then  made  and  checked  for  scale  dimensions, 
authenticity  of  detail  and  weight.  Since  the  detail  was,  on 
the  whole,  quite  intricate  for  so  small  an  object,  both  bob- 
bing and  mold  problems  had  to  be  continually  kept  in  mind 
in  making  the  model.  Even  at  that,  a  careful  finishing  job 
was  required  in  making  the  hob.  The  ordinary  two-part 
split  mold  was  out  of  the  question,  for  such  a  mold  would 
have  been  plagued  with  undercuts  in  several  directions.  The 
model  was  therefore  prepared  with  a  cam-action  die  in 
prmpeet 

The  toy  train  affords  an  example  of  a  design  problem  for 
which  definite  predesign  requirements  were  set  by  the  man- 
ufacturer. Submitted  to  us  at  a  somewhat  less  advanced 
stage  of  Conception  was  a  cellulose  acetate  coin  holder  which 
i>  al»iut  to  IH-  marketed  by  the  Herens  1'la-tic-.  Corp..  of 


Thii   simple   redesign   ol   original   conception   ol  a   scratch 
pad  deck  tray  avoided  complicated  mold  design  problems 


Brooklyn,  N.  Y.  The  Berens  firm  told  us  that  they  wanted  I 
coin  purse  which  (1)  would  be  all-plastics,  in-tead  of  I 
combination  of  plastics  and  leather,  (2)  would  be  a  ratlioa 
departure  from  the  usual  zippered  leather-cased  variety  aw 
(3)  would  contain  a  provision  for  the  half-dollar  in  additioi 
to  the  usual  compartmentation  for  dimes,  pennies,  nickel 
and  quarters.  In  the  course  of  designing  the  item,  wi 
decided  to  provide  for  bills  also. 

The  chief  reason  why  there  had  been  no  provision  fa 
half-dollars  in  the  usual  coin-holder  purse  was  mainly  tha 
the  addition  of  a  half-dollar  compartment  in  the  same  ele 
ment  and  in  the  same  plane  would  have  made  the  purse  toi 
large  and  unwieldy.  We  therefore  created  a  separate  ele 
ment  for  the  half-dollar,  making  this  as  flat  as  possible  ii 
order  not  to  increase  appreciably  the  over-all  thickn 
the  purse. 

Design  Requirements 

With  this  functional  matter  taken  care  of,  an  analysis  a 
the  design  requirements  showed  the  following:  (1)  I -nut 
the  point  of  view  of  appearance  and  for  the  elimination  of  i 
separate  fabricating  and  assembly  operation  at  the  point  a 
closure  of  the  purse,  the  clasp  must  be  molded  intejjrallj 
with  the  lids.  The  clasp  had  to  have  positive  closure  ii 
order  to  function  properly.  This  problem  was  solve' 1  l>j 
providing  a  small  frictional  nib  on  the  flat  under-siirface  o 
the  clasp.  (2)  In  addition  to  the  space  for  bills  inside  one 
of  the  lids,  provision  had  to  be  made  to  hold  the  bills  again 
falling  out  when  the  purse  was  opened.  This  meant  a  cli] 
of  some  kind  to  act  as  a  clasp  against  the  folded  bills, 
self-clasp  was  not  economically  feasible,  so  that  a  M-i>arat 
clement  was  indicated.  This,  in  turn,  meant  an  anchor 
the  clip.  The  problem  was  solved  by  working  into  the  dc-j 
sign  of  one  lid  a  small  niche  into  which  the  tensioned  end 
the  clip  could  be  inserted  with  a  single  finger-prc-sur« 
movement  in  the  course  of  assembly.  (3)  The  hinges  ha 
to  be  accurately  fitted.  (4)  The  shanks  of  the  coin  con 
partmcnts  had  to  have  either  a  positive  lit  or  a  barrier  to 
prevent  the  coins  from  dropping  out.  The  requirement  in 
this  instance  was  met  by  designing  tiny  nibs  into  the 
tremc  upper  ends  of  the  shank  channels  to  offer  friction 
passage  for  the  coins  at  that  point  with  free  jugate  along 
the  rest  of  the  channel. 

'I  he  total  design  included,  for  molding  purposes,  two  lids 


26 


f LAST MfS 


NOVKMKKR  194( 


The  Magic  of  Resins 

lies  unsuspected  in  scores  of  Sales  Successes 


rYOUR  HOME  has  insulation 
that  keeps  it  cooler  in  sum- 
mer, warmer  in  winter,  and  re- 
duces your  fuel  bill,  it  is  prob- 
ably "mineral  wool"  (mineral 
or  glass  fibres  in  the  form  of 
wool,  wool  bats,  blankets  or 
boards)  held  to  form  by  a  binder 
of  synthetic  resin. 

Resins  make  better  binders 
and  glues.  Resins  make  plastics. 
From  laminated  golf  clubs  to 
radios,  from  printing  inks  to 


NOVEMBER  1946 


resin-bonded-plywood  airliners, 
lower  manufacturing  costs  and  in- 
creased saleability  of  hundreds  of 
products  have  resulted  from  the 
use  of  resins. 


the  possible  appli- 
cations and  advantages  of  Interlake 
Phenolic  Resins  and  Molding  Com- 
pounds. Allow  us  to  work  with  you. 


IMIKIAKB 

CHEMICAL 

Corporation 

•    PRODUCTS     FROM    COAL    • 


INTEKIAKE  CHEMICAL  CORPORATION 
1935  UNION  COMMERCE  BUILDING 
CLEVELAND  14  •  OHIO 


PLASTtCS 


27 


a  channeled  coin  element,  a  tension-held  half-dollar  element 
and  two  thin  decorative  plaques.  These  were  all  to  be  in- 
cluded on  the  same  mold,  so  that  an  entire  purse  (less  as- 
sembly) could  be  produced  in  a  single  shot.  To  meet  the 
problem  of  the  equivalent  of  opposing  undercuts  at  several 
points,  a  five-cam  mold  construction  was  used.  Assembly 
was  reduced  to  insertion  of  the  hinge  pin,  insertion  of  the 
bill  clip  and  acetone  application  of  the  plaques  on  the  lids, 
and  simple  jigs  were  designed  for  the  quick  handling  of 
these  operation-..  What  we  feel  was  one  of  the  most  result- 
ful  elements  of  the  solution  of  these  various  problems  was 
that  the  manufacturer,  who  kept  in  touch  with  proceedings 
all  the  way  through,  gained  a  new  and  appreciative  insight 
into  the  complex  factors  involved  in  what  had  initially 
seemed  to  him  to  be  a  comparatively  simple  requirement. 

Good  Design 

An  exemplification  of  good  design  from  a  functional 
standpoint,  but  of  problem-generating  design  from  the  angle 
of  mold  design  principles  is  that  of  the  scratch-paper  desk- 
tray.  This  was  submitted  to  us  by  Mel  Meyers,  a  feature 
writer  for  plattlct,  who  visualized  the  required  mold  as  be- 
ing of  rather  interesting  cam  design.  He  recognized  the 
mold  problems  involved,  however,  and,  after  a  thorough 
discussion  of  the  economics  of  production  and  of  mold 
amortization,  he  agreed  with  us  that  the  cost  of  a  complex 
mold  would  not  be  justified  under  the  circumstances.  A 
change  in  design  for  the  model  was  therefore  made. 

When  he  put  the  first  sketch  before  us,  he  described  his 
purposes  as  follows:  In  the  usual  form  of  scratch-paper  tray, 
the  walls  are  vertical  on  three  sides,  with  a  wide  opening  in 
the  fourth  through  which  the  paper  is  drawn  out  of  the  tray. 
When  the  paper  is  drawn,  it  is  tripped  against  the  ribs  on 
either  side  of  the  wide  aperture.  This  tripping  causes  the 
paper  to  buckle  over  and,  occasionally,  to  slip  out  of  the 
hand.  This  is  especially  true  when  the  stack  of  scratch- 
sheets  in  the  tray  is  low.  His  intention  was  to  obviate  this 
tripping  by  providing  a  smooth  upward  slide  for  withdrawal 
of  the  paper,  with  a  relatively  narrow  aperture  functioning 
only  for  a  thumb-hold  and  not  for  egress  of  the  paper.  For 
hi-  -  pec  i  fie  purposes,  there  was  no  fault  to  be  found  with 


the  design.  The  trouble  was,  however,  that  the  arched  fronl 
and  back  walls  complicated  the  mold  design  and  made  i'oi 
correspondingly  high  mold  cost.  The  simple  redesign  illus- 
trated disposed  of  this  problem  without  seriously  altering 
the  effectiveness  of  the  product's  function.  The  two  curvet 
walls  were  brought  straight,  but  the  angle  of  incline,  aboul 
30°  off  the  horizontal,  was  retained. 

Redesign  of  Dice  Spinner 

Occasionally  it  is  hard  to  shake  a  customer  out  of  a  pre 
conceived  design  when  he  is  convinced  that  he  is  on  the  righ' 
track,  and  when,  a-  it  happens,  we  are  certain  that  he  is  not 
The  dice-spinner  illustrated  offers  an  example.   Fortunately 
the  cii-tomer'-  persistence  was  accompanied  by  a  sen-e  o 
humor.    The  drawing  had  been  made  by  the  customer  him 
self  who,  while  he  was  no  draftsman,  was  able  to  make  him 
self  clear  on  paper.     The  device  was  a  dice-spinner  for  a 
new  game,  and  a  requirement  of  the  game  was  that  only  the 
player  spinning  the  dice  was  to  see  the  result  of  the  throw 
at  the  time  of  the  spin.    The  drawing  shows  a  top  view  am 
a  cross-section  of  the  cup,  with  a  cross-section  of  the  cup 
holder  which  contains  the  bearing  hole  for  the  cup'-  pin 
shaft.    There  are  four  vertical  ribs  in  the  side  wall  of  the 
cup  and  it  was  in  these  rihs  that  the  crux  of  the  trouble  lay. 
The  ribs  were  intended  to  trip  the  dice  as  they  whirled  in 
the  cup. 

We  pointed  out  that  the  centrifugal  force  of  the  spin  would 
throw  the  dice  up  to  the  top  of  the  side-wall  at  the  point 
where  it  joined  the  transparent  covering  disc  and  they 
would  then  lodge  against  a  rib,  where  they  would  stay  until 
the  spin  died  down  and  permitted  them  to  slide  hack  to  the 
floor  of  the  cup.  Thus  there  would  be  no  tripping  of  the  dice. 
The  customer  was  certain  that  his  principle  was  correct,  s< 
much  so  that,  contrary  to  our  advice,  he  ordered  us  to  p 
ceed  with  a  model. 

A  few  test  whirls  of  the  model  proved  our  original  con 
tention:  there  was  no  tripping  of  the  dice.  Still  convincee 
that  his  rib  principle  was  right,  the  customer  then  >aid  that 
if  the  cup  were  made  to  revolve  in  a  vertical  plane,  centrifu 
gal  force  would  be  countered  by  gravity,  the  dice  would  go 
(Continued  on  page  92) 


Drawing  of  dice  spinner,  and  model.  Below,  model  in  the 
vertical  plane  having  proved  unworkable,  device  was  sue 
cessiully  redesigned  in  horitontal  plane,  with  wire  trip- 
per. Molding  difficulties  are  not  involved  in  new  design 


!•  I.. \STlfS 


NOYKMHKK   1946 


I 


plastics  i  resint 


STAN  DARD 

OF 
PURITY 


tttt  products 


CALCIUM  A 


a(C,H,0, 


synthetic  organic* 


Pharmaceuticals 


varnishes 


new  product? 


Quality  by  the  Carload 


B&A  Purified  Calcium  Acetate  in  commercial 
quantities  .  .  .  another  example  of  the  ability  of 
General  Chemical  Company's  Baker  &  Adamson 
Division  to  produce  quality  by  the  carload  in 
supplying  the  fine  chemical  needs  of  American 
Industry. 


Here  is  a  quality  chemical  .  .  .  assaying 
min.  Ca(C2H302)2<H;!0  .  .  .which  is  far  superior 
to  ordinary  acetate  of  lime  for  the  manufacture 
of  pharmaceuticals,  plastics,  food  products  and 


other  commodities  where  high  purity  of  process 
materials  is  indispensable. 

Many  are  the  established  applications  of  this 
B&A  Fine  Chemical.  Perhaps  it  has  a  place  in 
your  process  too.  If  so,  let  us  know  your  require- 
ments now.  And  remember— whether  you  need 
purified  Calcium  Acetate  in  bottle,  drum,  or  even 
carload  lots— Baker  &  Adamson  can  supply  it 
promptly  and  steadily.  That's  important  when 
your  production  schedules  press. 


NOVEMBER  1946 


GENERAL   CHEMICAL   COMPANY 

BAKER  &  ADAMSON  DIVISION 


40    RECTOR    STREET.    NEW    YORK    6.    N.    Y.  •• 


Sales  and  Ttchnical  Service  Offices :  Albany*  •  Atlanta  •  Baltimore  •  Birmingham*  •  Boston  •  Bridgeport 
Buffalo*  •  Charlotte*  •  Chicago*  •  Cleveland*  •  Denver  •  Detroit*  •  Houston  •  Kansas  City 
Los  Angeles*  •  Minneapolis  •  New  York*  •  Philadelphia*  •  Pittsburgh*  •  Providence  •  St.  Louis* 

San  Francisco*    •    Seattle    •    Wen atchee  (Wash. )    •    Yakima  (Wash.) 

In  Wisconsin :   General  Chemical  Wisconsin  Corporation,   Milwaukee,   Wis. 

In  Canada :  The  Nichols  Chemical  Company,  Limited   •   Montreal*    •   Toronto*   *   Vancouver 


SETTING       THE       PACE 


IN       CHEMICAL       PURITY       SINCE       1882 

•  Complete  stocks  carried  here. 


PLASTICS 


29 


Each  of  the  new.  edgelighted  "Plexiglas"  murals  in   Hole!  Sheraton  Lounge  depicts  a  scene  of  old  New  York 

Edgelighting  Murals 


ONE  OF  the  features  of  the  Plexiglas  "Dream  Suite" 
which  Rohm  &  Haas  Company  sent  on  a  nation-wide 
exhibition  tour  last  year  has  stepped  out  of  the  dream  and 
become  a  reality.  From  a  designer's  project,  the  Plc.rii/las 
murals  which  were  such  a  striking  part  of  the  suite  have 
HI  UK-  intu  production,  and  fourteen  of  them  have  been  in- 
stalled in  the  lounge  of  the  Sheraton  Hotel,  New  York  City. 
where  they  were  officially  unveiled  on  October  1.  They  were 
designed  and  executed  by  the  Endicott  Corporation,  of  Bos- 
ton, Mass. 

The  murals  arc  produced  on  a  single  sheet  of  Plexiglas, 
although  it  is  possible  to  use  two  or  more  sheets,  each  con- 
taining part  of  the  design.  The  picture  in  the  Sheraton 
murals  is  achieved  with  various  techniques.  There  are 
scribed  lines  in  various  depths,  a  wide  cut  giving  the  maxi- 
mum light,  and  tine  lines  supplying  the  effect  of  a  wood  en- 
graving. In  one  of  the  murals  a  three-dimensional  tree  trunk 
is  achieved  by  a  sensitive  gradation  of  thickness  and  length 
of  the  cuts,  which  is  in  effect  a  drawing  in  light  and  shade. 
Other  portions  arc  painted  in  green,  red,  yellow  and  other 
color  tones,  each  reflecting  its  own  hue.  Cloud  and  similar 
fluffy  mass  effects  may  be  obtained  by  rubbing  steel  wool 
over  the  desired  area.  When  edge-lighted,  the  complete 
scene  appears  in  light  and  color  as  well  as  in  three  dimen- 
sions; hence  the  term  "painting  in  light,"  which  has  been  ap- 
plied to  the  medium. 

Ranging  in  sire  from  30"  by  40"  to  36"  by  48",  each  mural 
is  individually  mounted  in  a  shadow  box.  ami  illumination 
is  furnishrd  by  fluorescent  tubes  concealed  within  the  box 
frames.  Since  the  designs  reflect  most  of  the  light  playnl 
on  them,  the  murals  are  used  not  only  as  decorations,  but  to 
supplement  the  regular  lighting,  as  well. 

The  method  of  design  and  fabrication  of  the  Sheraton 
(Conliimfd  on  page  96) 


A  "Plexiglas"  panel,  on 
which  is  engraved  a  de- 
sign to  be  edgelighted 


"Masonite"  die  stock, 
used  to  form  a  back- 
ground for  the  design 


C  Light  filter  of  tinted 
plastics  for  color  ef- 
fect on  engraved  lines 


D  Fluorescent  light  source 
applied  at  edge  of  mural 
to  suit  space  and  design 


E  Center  alignment  of  light 
source  with  "Plexiglas"  pan- 
el for  maximum  brilliance 


F  Air  space  to  permit  ex- 
pansion and  contraction 
of  the  "Plexiglas"  panel 


G  I'on  support  frame  for 
mounting  and  contain- 
ing the  finished  panel 


H  Hanger  stud  which  per- 
mits plastics  lo  hang 
free,  to  avert  warping 


J  Felt  gaskets  keep  out 
dust,  allow  expansion 
within  the  Iron  frame 


30 


PL.ltiTH  * 


N0\  KMHKH    I! 


p^^  ^^^  Y^^x 


Light-weight  -  Resilient 

NATIONAL 

VULCANIZED    FIBRE 
protects  against  shock  and  strain 
...  in  products  or  plant  equipment 


If  it's  a  rugged  material  you  want  to  protect  your  prod- 
ucts or  plant  equipment  against  shock  and  strain 
— you're   sure   of  getting   it   in   tough,    durable 
National  Vulcanized  Fibre! 

One  of  the  strongest  materials  per  unit  weight 
known,  this  versatile,  hard  vulcanized  fibre  can  "take 
it"  in  every  way.  Resilient  and  light  in  weight 
(about  half  that  of  aluminum),  it  has  outstanding 
impact,  tensile  and  dielectric  strength  ...  is 
extremely  resistant  to  wear  and  abrasion  .  .  . 
and  is  machined  and  formed  easily,  economically. 
You  get  all  this  and  toughness,  too,  in  National 
Vulcanized  Fibre. 

To  be  sure  of  improved  performance  for  your 
products  or  plant  equipment,   let  a  trained 
National  engineer  show  you  how  this  rugged 
material  can  be  readily  adapted  to  your 
production.  Write  for  information. 


^"•lH^mmks  must  be  built  to  "take"  the 
•  1ft rd  knocks  to  which  they're  sub- 
jected. That's  why  so  many  of  them 
— including  U.  S.  Army  foot  lockers 
—  are  made  of  rugged  National 
Vulcanized  Trunk  Fibre. 


NATIONAL  VULCANIZED  FIBRE  COMPANY 


Wilmington  99,  Delaware 


Offices  in  Principal  Cities 


NOVEMBER  1946 


PLASTICS 


31 


Buildin 


The  new  "Plaskon"  dispensers  come  in  a  variety  of  attrac- 
tive colors,  operate  with  precision,  and  insure  a  fully 
controlled  flow  ol  condiment.  Right,  cross-sectional  view 


New-type  moisture-proof  salt  am 
pepper   dispensers   avoid   cakin* 
insure  ample  supply  of  con  dim  en  J 


THE  proverbial  better  mousetrap  is  more  than  rivaled  in 
functional  values  by  recently  developed  salt  and  pepper 
dispensers  which  owe  much  to  plastics  for  their  durability 
and  quality  of  performance.  Now  being  marketed  by  the 
Sonette  Plastics  Company,  Chicago,  the  new  dispensers  do 
away  with  the  nuisance  of  shaking  and  caking,  and  always 
insure  an  ample  supply  of  the  condiment  regardless  of  the 
humidity. 

Somewhat  similar  to  previous  plastics  dispensers  oper- 
ating on  the  plunger  principle,  this  new  device  is,  however, 
o.iiM<lered  superior  because  of  (1)  the  type  of  plastics  ma- 
terials tiM-d  in  its  construction,  (2)  the  instrument-like  pre- 
rision  and  efficiency  with  which  it  operates,  and  (3)  the 
moisture-proof  vacuum  seal  which,  by  keeping  the  salt  (or 
pepper)  free  from  exposure  to  dampness,  insures  a  fully 
controlled  flow  under  the  worst  conditions  of  external  hu- 
midity. 

Principle  of  the  dispenser  is  simple.    A  button  at  the  top 

Valve  assembly  stems  are  cut  Irom  rod  stock  extruded 
from   transparent   "Tenite   II".    Average  length   is   27i 


is  attached  to  and  controls  a  stem,  to  which  is  attached  at  thi 
lower  end  a  rubber  valve  secured  to  the  stem  by  friction  ;itx 
vacuum.    The  valve  seats  on  the  outer  edge  of  the  oprniiqf 
in  the  center  of  the  bottom  cap.    When  the  stem  is  pu>lie 
down,  by  means  of  the  button,  the  valve  is  also  pushed  dowi 
and  away  from  its  contact  with  the  bottom  cap  which  MK  \v 
into  the  housing  containing  the  condiment.     Flicking  tli 
button   with  the  forefinger  dispenses  a   small   amount 
material.     More  abundant  quantities  may  be  released  by 
increasing  the  time  the  button  is  kept  depressed. 

The  dispenser  does  not  have  to  be  held  upside  down 
tapped  or  shaken.    The  shape  of  the  valve  and  the  design 
of  the  valve  seat  prevents  the  salt  from  releasing   in  I 
stream.     Instead,  the  salt  is  cascaded  in  a  circular  patter 
over  a  considerable  area,  the  extent  of  which  depend*, 
course,  on  the  height  at  which  the  dispenser  is  held  ah 
the  food  to  be  seasoned,  the  manual  procure  u~ed,  and 
angle  at  which  the  dispenser  is  held. 

A  spinning   fixture  screws  bottom  cap  and  housing  to- 
gether    another  step  in  assembly  process  at  Foster  Co. 


Better  "Shakers 


u      V.    C*.    LjibbenA 


Double  action  springs  used  to  hold  valve  firmly  seated 
against  opening  in  bottom  cap  are  inserted  into  housing 


Filling  the  dispenser  is  easy.  The  valve  stem  and  valve 
are  depressed  with  the  button,  the  valve  is  pulled  off  the 
stem,  the  cap  is  unscrewed  and  removed,  and  the  housing 
is  filled  with  the  desired  seasoning  material.  Disassem- 
bling, filling,  and  reassembling  can  be  done  very  quickly. 

Sonettes,  as  the  new  "salts  and  peppers"  are  called,  con- 
sist of  housing,  bottom  cap,  button,  valve  assembly  stem, 
valve  and  springs.  The  housing  is  compression  molded,  in 
a  50-ton  press,  from  Plaskon  urea  formaldehyde  by  the 
Breyer  Molding  Co.,  Chicago.  Unlike  the  housings  in 
older  dispensers  of  the  same  general  type,  which  were  two- 
piece  jobs,  the  present  housing  is  molded  in  one  piece  except 
for  the  bottom  cap.  Advantages  claimed  for  urea  formal- 
dehyde over  the  thermoplastics  used  in  older  housings  in- 
clude greater  heat  resistance,  dimensional  stability,  strength, 
and  durability  insured  by  a  %"  wall  thickness.  Many  of 
the  older  housings  failed  to  maintain  dimensions,  and  warp- 
ing soon  resulted  in  unsatisfactory  service.  Urea  formalde- 
hyde is  likewise  praised  for  its  color  depth  and  color  fast- 
ness, and  the  molded  housing  is  said  to  have  been  designed 
so  as  to  eliminate  crevices  or  lodging  places  where  dirt  can 
collect. 

The  bottom  cap,  molded  in  multicavity  compression  molds, 
is  also  made  of  urea  formaldehyde.  The  cap  is  threaded  for 
screwing  into  the  housing.  Considerable  accuracy  in  mold- 
ing is  required  because  it  is  essential  that  nearly  perfect 
concentricity  be  maintained.  It  is  necessary  to  exercise 
great  care  in  maintaining  alignment  of  plunger  cavity  with 
relation  to  the  valve  seat. 

The  button  is  made  on  an  automatic  screw  machine  from 
rod  stock  extruded  of  Tenite  II  (cellulose  acetate  butyrate) 
by  Superior  Plastics  Co.,  Chicago.  This  material  com- 
bines suitable  flexibility,  machinability,  and  satisfactory  soft- 
ening point,  and  extrudes  to  close  tolerance.  The  hole  in 
the  button  is  held  to  a  tolerance  of  ±.0005"  in  diameter. 
Holes  are  drilled  in  groups  with  diameters  ranging  from 
.121"  to  .124".  Valve  assembly  stems  are  fitted  to  the  but- 


A  rubber  valve  is  placed  on  end  of  stem,  and  the  unit 
is  inserted  into  the  case  through  a  hole  in  bottom  cap 

tons  to  give  a  press  fit.  In  order  to  obviate  effect  of  creep- 
age,  the  button  is  also  glued  on  the  stem  to  insure  perma- 
nency of  the  fit.  Buttons  must  be  perfectly  concentric  in 
order  to  insure  accurate  seating  of  the  valve  and  insure 
smooth  operation.  They  are  manufactured  by  the  Redmer 
Sons  Co.,  Chicago,  half  in  white  for  salt  and  half  in  black 
for  pepper. 

Valve  assembly  stems  are  cut  from  rod  stock  extruded 
from  transparent  Tenite  II  by  Superior  Plastics  Co.,  to  a 
tolerance  of  ±  .002".  They  are  cut  at  machine  gun  speed 
in  a  cutter  which  was  specially  designed  for  the  job  by  the 
Sonette  Plastics  Company  and  which  is  said  to  have  only 
one  moving  part.  A  collar  is  put  on  the  stem  before  the 
button  is  press  fitted  into  place  in  order  to  seal  the  spring 
mechanism  and  prevent  disassembly  when  the  valve  is  re- 
moved for  re-filling. 

The  springs  used  to  hold  the  valve  firmly  seated  against 
the  opening  in  the  bottom  cap,  through  which  dispensing  is 
accomplished,  are  made  of  stainless  steel  to  resist  rust  and 
corrosion.  Valves  are  compression  molded  in  a  multiple 
cavity  mold  from  a  special  pure  food  rubber  compounded 
to  resist  salt,  abrasion,  and  surface  checking  due  to  ozone. 

The  assembling  of  these  various  parts  into  the  completed 
product  is  being  done  by  the  Foster  Company  of  Chicago. 

Although  the  Sonette  Plastics  Company  is  making  dis- 
pensers also  in  metal,  it  favors  plastics,  especially  for  the 
housing  and  the  bottom  cap,  because  plastics  have  low  ther- 
mal conductivity,  are  not  conducive  to  the  condensation  of 
moisture,  and  do  not  attract  moisture  on  the  inside,  thus 
keeping  the  salt  from  caking.  Plastics  also  offer  color  pos- 
sibilities not  available  in  metal,  weigh  much  less  than  metal, 
and  unlike  metal  do  not  corrode. 

Sonettes  are  now  being  made  in  black,  white,  and  six 

Fiesta  colors — yellow,  red,  blue,  ivory,  orange,  and  green. 

A  combination  being  marketed  has  a  red  housing  with  a 

gold  cap,  and  plastics-lined  gold  and   rhodium  dispensers 

(Continued  on  page  79) 


NOVEMBER  1946 


PLASTICS 


33 


Toil  cone  of  the   XB  35   is   fabricated  completely 
from  "Fiberglas"  impregnated  with  liquid  slyrene 


Aircraft 
Feature  JVew 

Laminates 


Laminated  plastic*  vertical  antenna  malt  used  on 
new  Northrop  bomber  hat  balsa  core,  is  36    long 


DESPITE  a  smlden  me-ea-e<l  -upp'y  of  a'uniinum,  mag 
nesium,  and  other  war-critical  metals,  development  o 
all  plastics  aircraft  parts  continues  as  a  major  activity  ir 
the  Process  Laboratories  at  Northrop  Aircraft  Company 
This  research  is  founded  on  a  logical  basis — extensive  tot: 
have  proved  that  plastics  are  better  suited  to  certain  appli- 
cations than  are  any  of  the  metals. 

One  material  that  is  receiving  considerable  attention  at 
this  time  is  a  plastics  laminate  fabricated  by  impregnating 
a  Fiberglas  with  liquid  styrene.  The  high  strength,  shock 
resistance,  abrasion  resistance,  and  low  strength  weight 
ratio  of  this  material  are  distinct  assets  when  parts  must  tx 
strong,  rigid,  and  of  minimum  weight.  Recently-developec 
parts  using  this  material  include  various  types  of  antenna 
masts,  compass  loops,  fairings,  fuel  tank  backings,  and  heat 
insulating  washers.  Many  of  these  parts  are  installed  it 
the  new  Northrop  Flying  Wing  Bomber. 

The  Fiberglas-styrene  parts  are  formed  either  by  low 
pressure  lamination,  or  by  the  vacuum-pressure  process 
Polymerization  of  the  styrene  after  impregnation  is  ex 
pedited  by  heating  to  265°  F,  and  by  use  of  technical  lauroy 
peroxide,  a  soluble  catalyst. 

Various  Antenna  Masts 

Several  types  of  antenna  mast  are  being  produced.  Thes« 
are  not  only  stronger  than  metal  masts  of  equal  weight,  bu 
are  immune  to  fatigue  cracks  caused  by  continuous  high 
amplitude  vibrations.  This  type  of  failure  is  common  with 
metal  mast  installations.  The  laminated  plastics  masts  are 
sufficiently  strong  and  rigid  as  formed,  and  require  no  sup 
plementary  bracing. 

One  of  the  masts,  approximately  10"  long,  is  anchoret 
to  the  airplane  by  y2"  bolts  inserted  through  the  laminate. 
The  installation  more  than  meets  the  3-10-lb  design  re 
quirements.  The  high  dielectric  properties  of  the  laminate 
makes  possible  anchorage  of  the  aerial  wire  directly  to  the 
mast  without  use  of  supplementary  insulators. 

A  second  mast,  36"  long,  tapering  from  4J4"  at  the  base 
to  2Yt"  at  the  tip,  and  \y*"  thick,  utilizes  a  balsa  core. 
When  supported  at  both  ends,  this  mast  will  uphold  a  tesl 
weight  of  1200  Ibs.  It  is  attached  to  the  airplane  by  "casting" 
it  in  a  magnesium  base,  using  styrene,  with  walnut  Hour 
filler  as  the  cementing  material. 

All  antenna  masts  are  formed  by  the  vacuum-pressure 
process.  The  impregnated  glass  cloth  is  laminated  on  at 
ordinary  plaster  male  core  which  can  be  easily  shattered 
and  removed  when  the  mast  is  finished.  The  bag  material 
is  very  thin,  transparent  polyvinyl  alcohol  sheeting.  The 
laminated  mast  assembly  is  wrapped  in  the  sheeting,  then 
the  sheeting  edges  are  sealed  with  moisture.  This  Iwj 
material  adequately  withstands  the  necessary  forming  tem- 
peratures and,  when  the  part  is  completed,  can  be  torn  away 
and  discarded.  It  is  economical,  and  convenient  to  use. 

The  compass  loops  and  fairings  are  formed  in  the  same 
manner.  The  high  dielectric  properties  of  the  Fibfr<ilas- 
styrene  combination  are  distinctly  advantageous  in  all  types 
of  radio  installation.  A  prior  development  at  Northrop  was 
use  of  this  material  for  forming  the  radar-enclosing 
of  the  P-61  Black  Widow  night  fighter. 

All-Plottlc*   fairings 

The    artificial    fairings    are    used    at    variou 
throughout  the  airplane.    One  important  application 
of  an  all-plastics  fairing  for  the  trailing  antenna.     Thi! 
fairing  must  operate  in  full  slipstream  during  flight,  and 
must  withstand  continuous  vibration  without  supplementary 
supports. 

The  tank  barking  sheets.  IIM-(|  a-  supports  for  larp 
tank  installations  m  the  .Y/?-.?5,  are  of  the  same  l-'il>rrril,is- 
styrrno  combination,  and  are  formed  by  low  pressure  lami- 
nation.    Three   layers  ,,f   the   impregnated  glass  cloth  are 
i  (  :»ttinnrd  OH  page  85) 


34 


Product  of  TELEX,  Inc.,  Minneapolis,  Minn. 


TELEX 


tells  an  impressive 


PLASKON 


story 


The  TELEX  under-pillow  speaker  is  a  new  and  extremely 
rugged  electro-magnetic  sound  generating  unit.  It  is  de- 
signed for  normal  sound  reproduction  when  placed  under 
a  pillow,  or  as  a  personal  radio  soft  speaker  not  requiring 
headphones.  Thousands  already  are  in  use  in  hospitals, 
hotels,  homes,  Pullman  cars,  bus  lines,  air  lines  and  other 
places  where  soft,  high-fidelity  radio  reproduction  is  desired. 

The  TELEX  under-pillow  speaker  is  an  ideal  application 
of  Plaskon,  using  almost  every  one  of  the  many  advantages 
of  this  versatile  plastic  material.  The  beautiful,  rich-looking 
case  is  strong  and  shock-proof,  not  easily  damaged,  and 
adequately  protects  the  enclosed  electrical  mechanism.  The 
vibrating  sound-generating  surface  is  inductively  coupled 
to  the  electro-magnetic  structure.  The  absence  of  cemented 
connections  assures  clear,  rattle-free  performance  ^hiough- 
out  the  life  of  the  instrument.  The  hermetically  sealed, 
continuous  housing  makes  it  impossible  for  the  user  to 
tinker  or  tamper  with  the  operating  elements. 

Plaskon  Molded  Color  makes  this  TELEX  unit  warm  and 
friendly  to  the  touch.  The  gleaming,  colorful,  non-porous 
surface  will  not  tarnish,  check  or  corrode.  It  is  impervious 


to  the  action  of  oils,  greases,  alcohol,  acetone  and  other 
common  solvents. 

Plaskon  materials  have  distinctive  features  that  give  them 
wide-spread  application  in  the  electrical,  cosmetic,  drug, 
garment  and  many  other  industrial  fields.  We  shall  be  glad 
to  help  you  adapt  the  many  advantages  of  these  versatile 
materials  to  your  manufacturing  and  merchandising 
needs.  Write  for  free  illustrated  book  on  Plaskon  plastics. 


MOLDED    CO  LOR 


5PREF 


Wtt 


EVER  hear  of  a  vacuum  cleaner — so  big  — 
it  spreads   out   over  an  entire  plant  ? 
Well  ...  we  have  one  at  Boonton. 

Walking  through  the  plant  with  important 
papers  means  you'd  better  bypass  the  spot 
Bonny  Boonton's  decided  to  tidy  up.  For 
otherwise,  you  might  have  difficulty  retriev- 
ing your  belongings  from  the  vacuum  system! 
One  huge  unit  -piped  to  the  remotest  cor- 
ners of  the  plant,  supplies  suction  for  instant 
cleaning  wherever  it's  needed. 

And — a  clean  plant  means  clean  machines, 
and  clean  machines  mean  clean  raw  materials, 
dust-free  and  clean  molded  parts. 

Do  you  like  such  molded  parts?  Then  see  us. 


<r 


BOONTON  MOLDING  COMPANY 

HOLDERS  OF  MOST  PLASTICS  BY  MOST  METHODS 


FOR  OVER  25  YEARS 
CUSTOM  ENGINEERS 
OF  MOLDED  PLASTICS 


122  EAST  42nd  ST.,  NEW  YORK  17  • 


SUITE  1714  f 
MURRAY  HILL  t  1)40 


FACTORY-BOONTON.  New  Jersey 


Portable  molded  plastics  units  are  designed  on 
simple  classic  lines,  can  be  arranged  to  serve 
double  duty  as  bookcase  and  part  partition, 
combined  in  many  ways  to  fit  available  space 


Designing 
Functional  Furniture 


Problem  of  too  tew  closets  could  be  solved  with  portable  units  which 
offer  concealed  space  and  yet  add  to  appearance  of  room 


oL 


oui6e 


PLACE  for  everything,  and  everything  in  its  place" 
is  an  old  saying,  which  has  never  been  more  per- 
tinent than  now,  when  those  long-heralded  model  homes 
with  all  built-in  conveniences  are  still  in  the  future  and  we 
are  grateful  for  the  old  home  or  apartment,  with  its  too  few 
closets  and  limited  storage  space. 

A  portable,  molded  plastics  unit  which  will,  in  a  sense, 
constitute  its  own  "place"  in  these  otherwise  crowded 
quarters,  could  be  combined  in  a  variety  of  ways  to  fit  any 
available  space.  Designed  on  simple,  classic  lines,  it  would 
be  flexible  enough  to  fit  into  traditional  as  well  as  modern 
decor.  ' 

No  Technical  Difficulty 

With  many  presses  in  the  plastics  industry  already  turning 
out  large  molded  pieces,  and  heavier  presses  being  made, 
there  is  no  technical  difficulty  in  the  way.  Molding  such 
items  in  quantity  would  inaugurate  a  new  price  level  within 
the  reach  of  modest  incomes.  Cost  of  the  molds  and  all  in- 
itial investment  would  soon  be  amortized  by  the  quantities 
produced  and  sold,  for  the  demand  for  such  an  item  is  very 
real. 

The  urgency  for  finding  extra  cupboard  space  or  a  dual- 
purpose  piece  of  furnishing  suggests  the  simple  idea  of 
individual  units,  molded  of  plastics,  as  shown  in  the  accom- 
panying sketches.  They  can  be  acquired  piece  by  piece, 


according  to  room  needs  and  individual  taste,  are  small 
enough  to  carry  about  and  are  easy  to  assemble.  They  lend 
themselves  to  artistic  arrangement  in  any  part  of  the  house 
and,  because  of  their  small  size,  will  fit  into  an  odd  nook  or 
corner  and  glorify  wall  space  which  is  too  small  for  any- 
thing else. 

The  units  are  designed  in  two  sizes.  The  smaller  book- 
case size  is  open-faced  and  convenient  for  storing  books, 
small  household  gadgets  and  ornaments.  The  larger  type  is 
actually  a  deep  cubicle  equipped  with  hinged  door;  airtight 
and  dust-proof,  it  is  suitable  for  storing  large  pieces  of 
household  goods. 

Strong  and  Durable 

Both  units  are  molded  of  high  impact  material,  possessing 
structural  strength  and  durability.  Any  one  of  the  raw 
material  manufacturers  will  advise  on  the  material  best 
suited  to  this  type  of  article  and  the  molding  methods.  Mold 
costs  might  average  about  $6000  to  $8000  for  a  single-cavity 
mold,  although  prices  on  molds  would  vary,  according  to 
material  used  and  engineering  intricacies. 

The  small  unit  or  bookcase  type  measures  about  12"  by 
10"  by  8"  and  accommodates  eight  to  ten  books  or  their 
equivalent  in  bulk.  The  unit  is  light  in  weight  and  has 
dimensional  stability.  These  open-face  units  are  developed 
by  compression  molding  of  gleaming  jet-black  phenolic,  with 
fine  gold  tracery  outlining  the  carved  section  of  upper  edge. 
The  lower  edge  of  the  bottom  wall  has  a  metal  insert,  mold- 
ed with  the  case,  which  fits  into  the  grooved  section  on  the 
upper  edge  of  the  corresponding  unit  and  is  concealed  under 


NOVEMBKR  1946 


rLASTMCS 


37 


Most    rooms   contain   odd   corners   which   can   hold 
molded  units,  providing  much  needed  storage  space 


the  narrow  cuff.    This  simple  interlocking  device  keeps  the 

i  inbled  units  firm. 

Units  intended  for  the  base  are  selected  without  the  lower 
metal  insert.  The  wall  thickness  throughout  is  3/16".  Inner 
surface  of  units  are  rounded,  which  facilitates  cleaning  and 
prevents  dust  collecting  in  the  cracks.  In  any  event,  the-.- 
units  are  easily  cleaned,  requiring  only  a  damp  cloth  to 
remove  all  grime. 

A  little  ingenuity  in  grouping  these  individual  units  not 
only  adds  a  distinctive  note  to  any  room,  but  provides  it  with 
a  quota  of  storage  space,  as  well. 

For  bathroom  and  nursery,  delicate  pastels  to  blend  in 
with  lighter  furnishings  are  suggested.  Several  units 
stacked  in  the  nursery  would  be  handy  for  baby  accessories. 
Either  the  small  or  larger  unit  illustrated  here  offer  extra 
space  for  towels  and  cosmetics.  The  laundry,  garage,  pan- 
try, play-room,  patio  or  boathouse — each  could  have  its  share 
of  these  handy,  compact  cupboards. 


These  small  units  can  he  arranged  to  do  double  duty 
bookcase  and  part  partition.    They  can  be  banked  agains 
the  sides  of  the  fireplace  or  flush  with  the  wall.    AnotheJ 
idea  would  be  to  stack  some  of  the  small  units  in  an  uneve 
grouping  in  the  foyer  for  guest  wardrobe  u-.-.     Hat-  an 
handbags  or  rubbers  could  easily  be  stored  there  and  kep| 
available. 

The  larger  cubicles  might  be  developed  in  a  rich  cuinahaJ 
red,  with  a  dull  finish.  There  is  also  a  slight  hint  of  Chinese] 
in  this  simple  design  consisting  of  a  shallow  depn 
spherical  in  shape.  Molding  one  unit  with  the  desifl 
raised  and  slightly  convex  and  a  corresponding  unit  witlj 
the  same  design  concave,  an  ingenious  dovetailing  would 
ensue  and  keep  the  units  firmly  interlocked.  This  could  be 
carried  further  by  molding  this  design  on  the  sides,  a 

Low  pressure  molding  is  suggested  for  this  size,  whidj 
measures  14"  square  and  is  deep  and  roomy  enough  t. 
individual  pieces  of  clothing,  blankets  and  winter  tiling! 
safely  mothproof,  as  well  as  holding  phonograph  recnrds 
games,  children's  toys  and  other  article-  which  accumulate 
in  every  home. 

Modern  Coffee  Tobies 

Two  pairs  of  the  larger  units  set  a  few  feet  apart,  am 
supporting  a  large  slab  of  plate  glass,  form  one  of  the  new 
elongated  coffee  tables.     The  interior  of  these  four  unite 
would  be  useful  as  a  place  in  which  to  keep  magazin 
periodicals. 

Needless  to  say,  every  room  with  its  varying  wall  space 
and  contour  would  suggest  new  way-  to  arrange  these  units, 
and   many    varied   effects   are   possible   by    intereha: 
colors. 

The  "all-purpose  room,"  as  portrayed  in  the  accompany- 
ing sketches  and  featured  so  much  in  all  new  home  planning, 
has  a  distinct  affinity  for  all-purpose  furnishings,  and  -ince 
the  uncluttered  and  spacious  room  is  increasing  in  popular- 
ity, everything  should  be  done  to  concentrate,  in  a  fe\\  pieces 
of  furniture,  all  that  is  needed  for  use  and  comfort.    To  this 
end  a  dual  functional  table  is  depicted,  which  tie-  in  per- 
fei-tly   with  the  general   styling  of  room  and  companion 
pieces.    It  opens  gently  and  easily  directly  in  half,  revealing 
two  large  compartments  within  the  roomy  cabinet  ba- 
of  wood,  complete  with  dishes  and  linens.     Openr 
shutting  are  controlled  by  a  gate  hinge  which  holds  - 
apart  when  open,  and  is  concealed  in  the  groove  on  the 
lower  edges  of  cabinet  when  the  table  is  closed. 

The  choice  in  material  for  the  table  top  is  decorative 
1'arku'ood.  in  which  the  resin  impregnation  prescr- 
natural  softness  and  warmth  of  the  wood  veneer,  yet 
hard  glossy  finish  which  is  resistant  to  alcohol  and  ci| 
burns.     The  top  of  the  cabinet  is  envisaged  in  lipl 
lEngland  birch  for  contract  with  the  base  which  bear-  tl 
-ame  Chinese  motif  that  appears  in  the  built-in-. 


A  unique  ume  lot  two  portable  units  would  be  to  Ml  them  a 
lew  ieet  apart  supporting  a  large  §lab  of  gla«i.  thus  lorn 
Ing   a   modern-styled    coHee   table.    A   dual    lunetional   table 
opens   easily,   directly   in   hall,   to  house   dishes   and   linens 


M 


f  •  I .  \  S  T  1 1  - 


N()\  KMHKK 


A  BETTER  VIEW  WITH 


Passengers  like  these  new  Gray  Motor  Line 
buses  because  they  take  the  neck-craning 
out  of  sightseeing  in  the  Canadian  Rockies. 
And  unobstructed  vision  is  easily  provided 
with  curved  sheets  of  cry  stal-clear  PLEXIGLAS. 

5  PLEXIGLAS — made  famous  through  its  war 
use  on  every  type  of 
Army  and  Navy  plane 
— can  be  easilv  formed 


Only  Rohm  &  Haas  Makes 

Plexiglas 

Acrylic  Plastic  Sheets 
and  Molding  Powders 


to  fit  in  withjyour  new  bus  designs.  Its  excep- 
tional strength,  and  resistance  to  shattering 
and  weathering  assure  permanent  trans- 
parency and  long  service  life. 

|J  We'll  be  glad  to  give  you  information  or 
technical  assistance.  Call  or  write  our  nearest 
office:  Philadelphia,  Detroit,  Los  Angeles, 
Chicago,  New  York.  Canadian  Distributor: 
Hobbs  Glass,  Ltd.,  London,  Ontario. 


PLEXIGLAS  is  a  trade-mark,  Reg.  U.S.  Pat.  Off. 


ROHM    &    HAAS    COMPANY 

»ASHIi\CTON    SQUARE.     PHILADELPHIA     5.     PA. 

Manufacturers  of  Chemicals  including  Plastics .      Synthetic  Insecticides       Fungicidts     .  [nifties       Chemicals  lot  the  Lt  M*u(  Tf  iliis.  [nzmei»nr«.  Rubber  and  other  Industries 


Dark  colored  elements  in 
these  products  are  oi  phen- 
olic plastics  which  serve 
as  dielectrics,  while  die 
cast  housings  add  strength 


How  Plastics  Combine  With 
Die  Castings  &,  ju*  &„„ 


ANY  comprehensive  survey  of  the  uses  of  plastics  makes 
it  apparent  that  the  metal-working  industry  is  the 
outstanding  customer  for  molded  plastics  products.  This  is 
partly  because  plastics  and  metals  have  different  and  often 
directly  opposite  properties  and  one  is  frequently  needed  to 
supplement  the  other.  In  many  cases,  the  metal  component 
needed  is  most  economically  fabricated  as  a  die  casting. 
hence  die  castings  and  plastics  moldings  often  are  used  in 
close  and  mutually  beneficial  association. 

It  follows  that  the  accomplished  designer,  especially  of 
consumer  plastics  moldings  and  die  ca-tiiiK-,  must  know  how 
these  products  are  used  to  advantage  in  combination.  There 
is,  of  course,  a  degree  of  competition,  but  it  is  much  less 
important  than  the  supplementary  possibilities.  It  happens 
that  the  same  basic  machine-  u-ed  fur  injection  molding  arc 
applied  also  (with  different  heating  arrangements)  for  die 
casting,  benefiting  both  die  casters  and  plastics  molders.  A 
few  fabricators  make  both  classes  of  parts. 

The  following  arc  some  of  the  significant  difference-  U- 
tween  die  casting-  ami  pl.-f.ties  moldings: 

(1)  Plastics  are  good  dielectrics  and  somewhat  poor  heat 
conductors;  die  castings  are  good  heat  conductor-  and  fair  to 
good  as  electrical  conductor-. 

Many  pla-tic-  are  trans|xarcnt  or  translucent  ( though 
others  are  opaque)  :  die  castings  are  always  opaque. 

(3)  Most  plastic-  are  colorful  ami  require  no  applied  tin 
ish,  as  a  rule;  die  ca-tings  have  only  metallic  colors  them- 
selves but  can  IK-  given  organic  coating-  of  any  color  or  can 
be  plated  readily. 

(4)  Mo»t  plastics  arc  relatively  low  in  strength  and  some- 


Die  coil  components  combine  with  translucent  "Tenite"  tin 
ger  grips  and  escutcheons  in  Chrysler  window  regulators 


40 


!•  I.  AST  II   * 


\u\  I  MUKK    l'«Ki 


YOU'VE  EVERYTHING  TO  GAIN  JLJf 
GETTING  IN  TOUCH  Wl 


OR  THE 
PRINGS 
YOU   NEED 


Ask  us  to  make  your 
springs  for  you.  Find  out  for 
yourself  that  we're  pleasant 
people  to  do  business  with  .  .  . 
that  we  make  your  springs  exactly 
the  way  you  want  them  . . .  and  that  —  here 
at  Accurate  —  you  receive  intelligent  coop- 
eration, quality   workmanship  and   on -time   deliveries. 

If  you  need  engineering  help,  you'll  discover  that  our 
engineers  can  quickly  help  you  determine  the  right 
spring  for  your  job.  Perhaps  our  engineers  can  improve 
your  product's  performance  through  proper  spring  appli- 
cation. You  can't  lose. 

ACCURATE  SPRING  MANUFACTURING  CO. 

3828    West  Lake  Street     •     Chicago  24,  Illinois 


NOVEMBER  1946 


PLASTICS 


41 


An  assortment  of  automobile  accessories  having  colorful  molded  plastics  handles  attached  to  plated  metal  components 


what  brittle;  die  castings  have  much  greater  strength  and 
toughness. 

(5)  Most  plastics  are  comparatively  soft  and  thermoplas- 
tics become  softer  at  moderately  elevated  temperatures ;  die 
castings  are  harder  and  the  most  used  types  are  affected 
little  by  temperatures  up  to  300°  F  or  higher. 

(6)  Plastics  are  not  subject  to  surface  corrosion  but  few 
types  are  recommended  for  continuous  exterior  exposures: 
die  castings  are  subject  to  tarnishing  and  other  surface 
corrosion  unless  coated  but  otherwise  are  little  affected  by 
exterior  exposures,  in  which  they  are  widely  used. 

(7)  Die  castings  are  much  more  stable  dimensionally  than 
nir.st  plastics. 

(8)  Most  plastics  are  much  lighter  in  weight  per  unit  of 
volume   than   die   ca.sting>:    but    the    strength-weight    ratio 
favors  the  die  i-.-i-.ting*  in  some  cases. 

With  these  and  other  differences  (which  vary  in  degree, 
depending  ujwm  which  specific  type  of  plastics  is  compared 
with  which  die  cast  alloy  i,  it  i>  i|tiitc  logical  to  combine  the 
two  classes  of  products,  applying  each  where  its  good  prop- 
erties are  desired  and  avoiding  each  where  disadvantages 
are  serious  or  outweigh  advantages. 

Die  castings  are  often  used  with  plastics  when  the  latter 
are  required  as  electric  insulators.  In  such  instances,  the  die 
casing  commonly  serves  as  the  primary  structural  or  -u]i 
porting  element  (generally  to  add  strength  and  stiffness  or 
U>th)  and  the  plastic-  act-  a*  the  dielectric.  In  addition,  it 
often  provides  a  desirable  contrast  in  color,  especially  for 
exposed  application^. 

In  the  die  cast  and  plated  electric  range  panel  illustrated, 
for  example,  there  are  cored  recesses  for  switch  handles  of 
white  plastics  and  for  a  translucent  plastics  button  in  front 
of  a  hidden  pilot  light.  Back  of  the  panel  are  mounted  mold- 


Rear  deck  emblem  and  direction  signal,   with  die  cast 
frame  and  letters  and  some  transparent  red  acrylic  parts 


Speed   nuts   fit  over  integral   projections  to  fasten   die  cast 
letters   to   transparent   plastics  element   on   direction   signal 


42 


srirti 


NOVKMHKR  1946 


Buick   rear  deck  emblem   and   direction   signal  unit  has  a  die  cast   frame   with  inserts  of 
transparent  red  acrylic.  The  rear  tail  light  serves  decorative  as  well  as  utilitarian  purpose 


Die  cast  horn  ring  has  deep  red  plastics  covers  for  spokes.  Other  exposed  surfaces  are  plated 


ed  plastics  switch  bodies  containing  brass  terminal  and  cop- 
per switch  elements.  There  is  also  a  molded  light  socket 
base. 

The  panel  itself  could  have  been  molded  from  plastics,  but 
then  would  have  lacked  the  strength  and  dimensional  stabil- 
ity of  the  zinc  die  casting  and  also  the  plated  finish  desired 
to  harmonize  with  other  trim  on  the  range.  Both  of  the 
louver  sections  at  the  ends  are  also  die  cast  and  plated  and 
are  hinged  to  the  main  panel.  These  sections  conceal  outlets 
that  also  involve  plastics  dielectric  components. 

Die  castings  and  plastics  are  also  combined  effectively 
where  the  latter  serves  as  dielectric.  In  these  cases,  the  die 
castings  act  as  supports  or  housings  or  both  and  provide 
extra  strength  as  well  as  pleasing  contrast,  some  being 
plated.  Threads  are  readily  die  cast  and  make  for  con- 
venience in  assembly,  but  threads  for  screws  are  usually 
tapped,  often  in  holes  cored  to  size. 

There  are  uncounted  cases,  of  course,  in  which  die  cast- 
ings and  plastics  are  combined  for  decorative  effect.  The 
plastics  commonly  provides  color  or  transparency,  and  the 
die  castings,  often  handsomely  plated  and  lending  color  con- 
trast, also  adds  strength  and  stiffness.  In  the  case  of  handles 


and  knobs,  the  plastics  is  pleasanter  to  touch,  largely  because 
it  is  smooth  and  is  not  a  good  heat  conductor  and  so  has  an 
agreeable  "feel." 

Products  such  as  the  automobile  accessories  are  examples 
of  applications  of  this  type,  the  knobs  and  handles  being 
colorful  plastics  and  the  metal  components  chiefly  die  cast- 
ings that  are  well  plated.  Similar  comments  apply  to  in- 
terior automobile  window  regulators,  such  as  those  which  are 
made  for  Chrysler.  Finger  discs  and  escutcheons  are  in 
Tenite  translucent  ivory,  the  crank  being  die  cast  and  plated. 

Adds  Color  and  Strength 

Most  interior  door  handles  are  die  cast  and  plated  but 
often  have  molded  plastics  escutcheons.  Ford,  however,  has 
used  a  dipped  plastics  coating  on  door  handles  and  other  die 
cast  interior  hardware,  adding  color  and  giving  the  feel  of 
plastics  but  providing  the  stronger  core  of  die  cast  zinc  alloy. 

Considerable  experimental  work  has  been  done  and  some 
production  parts  have  been  made  in  which  plastics  materials 
are  injection  molded  over  die  cast  cores.  A  strong  and 
enduring  product  results,  but  the  coating  has  to  be  rather 
thick  and  the  product  is  somewhat  expensive,  partly  because, 


NOVEMBER  1946 


PLASTtCS 


43 


Panel  lor  electric  range  is  die  cast  and  plated,  equipped  with  plastics   switch   handles  and   bases   lor   dielectric 


components 


in  addition  to  a  die  lor  making  the  die  cast  core,  there  must 
be  provided  also  an  injection  mold  in  which  the  die  casting 
is  held  as  an  insert  while  the  plastics  is  molded  around  it. 
In  consequence,  both  die  and  processing  costs  are  rather 
high. 

Another  way  of  doing  a  somewhat  similar  job  is  illustrat- 
ed here  in  the  refrigerator  handle.  In  this  instance,  a 
channel-shape  plastics  part  is  injection  molded  and  later  is 
applied  over  a  die  cast  core  which  happens  to  be  made  in  the 
>ame  plant  (Central  Die  Casting  Corp.).  Shown  in  this 
illustration  is  a  gate  of  two  die  cast  cores.  The  latter  have 
cored  holes  for  fastening  screws  and  the  die  casting  also  pro- 
vides added  strength.  Again,  the  plastics  adds  color  and  a 
smooth  "warm"  surface  pleasant  to  the  touch. 

Still  another  tv|>e  of  refrigerator  handle  combine-  a 
molded  plastics  latch-operating  portion  pivoted  to  the  plated 
die  cast  handle  which  takes  the  stress  of  operating  a  heavy 
door. 

All  American  automobile  manufacturers,  who  are  among 


Til*  gate   ol   two   die  caul   core*  oi  a   refrigerator    handle 
o»er  which  to  applied  molded  channel-shaped  plastic*  part 


the  most  progressive  and  efficient  metal  workers,  make 
extensive  use  of  plastics  for  interior  trim  as  on  instrument 
panels  and  steering  wheels,  for  example,  but  are  still  larger 
users  of  die  castings.  1946  Oldsmobiles  have  nearly  the 
entire  instrument  panel  die  cast,  but  some  contrasting  plas- 
tics parts  are  applied.  Ford  uses  plastics  panels  and  applies 
die  cast  parts. 

Hubs  and  Horn  Rings 

Not  a  few  cars  have  steering  wheels  with  molded  plastics 
rims,  but  hubs  and  horn  rings  are  die  cast  and  plated.  In 
some  cases  the  hub  has  a  transparent  plastics  cap  that  is 
painted  on  its  under  surface  after  filling  in  name  or  emblem 
recesses  that  show  in  a  contrasting  color.  Most  horn  rings 
are  now  entirely  die  cast,  but  an  older  die  cast  model  had 
spokes  covered  with  plastics  moldings  in  color.  These 
moldings  included  integral  projections  on  the  under  side  and. 
after  these  were  passed  through  holes  in  the  die  cast  and 
plated  spider,  the  projections  were  softened  and  spread  with 
a  hot  iron  to  effect  a  permanent  fastening. 

Die  castings,  too,  are  often  provided  with  integral  studs 
which,  after  passing  through  some  mating  component 
(sometimes  made  of  plastics),  are  spun  or  riveted  over,  or 
speed  nuts  are  applied.  This  is  done  on  the  Buick  rear 
direction  signal  which  has  a  die  cast  frame  with  in-, 
transparent  red  acrylic  (one  of  the  few  types  of  plastics  that 
withstand  exterior  exposure  indefinitely).  Individual  letters 
are  die  cast  and  plated  and  have  studs  that,  after  Ix-ing 
passed  through  holes  in  the  plastics  parts,  are  fastened  with 
speed  nuts. 

Nearly  all  automobile  radiator  emblems  include  plate  /inc 
alloy  die  casting  or  are  entirely  die  cast  but  some  have  trans- 
parent acrylic  inserts.  Here  again  the  plastics  aids  in  the 
decorative  effect,  and  the  die  casting  provides  a  strong 
contrasting  support. 

In  Household  Appliances 

Many  household  appliances  arc  among  the  products  that 
combine  die  castings  and  plastics  effectively.  Hoover  sweep- 
ers, for  example,  have  die  cast  aluminum  main  housin. 
which  there  is  a  phenolic  molding  that  covers  part  of  the 
motor.  This  molding  has  a  vinyl  light  window  There  are 
several  other  die  cast  and  molded  parts  in  this  and  other 
sweepers,  ami  their  accessories  also  include  both  die  castings 
and  molded  plastics. 

Numerous  makers  of  washing  machines  use  molded  plas- 
tic- agitators.  These  are  commonly  snp|>oited  on  a  die  ca-t 
post  fastened  to  a  gear  housing  that  is  often  die  cast.  Many 
other  parts  of  such  machine-  are  either  molded  or  die  ca-t. 
It  is  quite  common  to  tin.!  a  die  casting  supporting  and 
supplementing  the  molded  plastics  part. 

on  page  91 ) 


44 


NOVKMKKK   1946 


Lower  Tool  Costs 


FEWER  CAVITIES 


Increased  Production 


SHORTER  CYCLE 


Precision  Quality 

CONSOLIDATED-CONTROLLED 


Thif  handle  (A,  6)  and 
tocker  (C)  are  components  of 
a  home  hair-waving  unit. 
They  were  plunger  molded  for 
HAIGAR  INC.,  CHICAGO. 


The  handle  halves  (A,  B)  and  socket  (C)  of  this 
appliance  were  plunger  molded  of  general  pur- 
pose phenolic- in  production  quantities -in  less 
time  —  with  fewer  cavities  —  and  at  less  cost  than 
conventional  methods! 

Plunger  molding,  the  newer  approach  to  faster. 


onsolidated 


MOLDED  PRODUCTS 

309  CHERRY  STREET,  SCRANTON  2,  PA. 


more  economical  and  none-the-less  precise  process- 
ing, permits  the  molding  in  place  of  inserts  [Note 
Threaded  Insert  in  Socket  (C)].  Elements  when 
assembled  as  a  unit  (D),  exemplify  precision  mold- 
ing at  its  best! 

Of  prime  importance  is  the  fact  that  the  customer 
is  well  pleased  ...  his  product  well  served.  As  a 
result  of  this  and  countless  other  Consolidated- 
solved  problems,  we  invite  the  opportunity  to 
apply  our  know-how  to  any  and  all  custom  mold- 
ing assignments.  Should  you  be  planning  in  plas- 
tics, your  inquiry  will  be  appreciated. 


PRODUCT  DEVELOPMENT  •  MOID  DESIGN  •  MOID  CONSTRUCTION  •  PLUNGER  MOLDING    •  TRANSFER  MOLDING  •  INJECTION  MOLDING  •  COMPRESSION  MOLDING 
Ironcfiol:  NEW  YORK,  1790  Broadway  •  CHICAGO,  549  W  Rando/ph  Si  •  DETROIT,  550  Maccofceei  lido   •  CLEVELAND,  «oU  Protpecr  Av   •  BRIDGEPORT,  II  Roily  Ridge  Dr. 


VOVEMBER  1946 


PLASTICS 


45 


The  softly  swirled  folds  of  Rose 
Saphire's  large  beret,  made  of 
multi-stripped  "Plexon"  yam. 
are  unaffected  by  summer  rains 


Soft  white  of  hat  is  accentuated 
by  brilliant  colors  of  "feather" 
trim,  in  thi*  Florence  Reichman 
all-plastics  slick  Breton  sailor 

Cone-shaped,  with  a  duff  brim, 
a  stunning  John-Frederics  hand- 
crocheted  hat  portrays  the  ver- 
satility of  new  "Plexon"  yarn 


Acmf 

•  ••   •    . 


Styles  Millinery 


TOP  FLIGHT  millinery  designers  are  now  making  some 
of  their  most  fashionable  hats  of  Plexon,  the  plastics 
coated  yarn,  which,  as  the  1941  annual  report  of  the  Smith- 
sonian Institute  predicted,  already  has  ".  .  .  found  many 
interesting  and  technical  applications  in  the  textile  indus- 
try." Fashion  accessories  now  being  made  of  Plexon  in- 
clude, in  addition  to  hats :  belt-,  purses,  neckwear,  gloves 
and  shoes. 

1'lexon  is  playing  a  big  role  in  adding  to  the  smart  ap|>ear- 
ance  of  today's  well-dressed  woman,  and  indication-  point 
to  still  further  use  of  this  material  in  future  apparel. 

This  plastics  coated  yarn,  which  is  used  as  a  woven 
fabric  and  may  also  be  crocheted  and  knitted  by  hand, 
twisted,  braided,  knotted,  is  waterproof,  colorfast,  resistant 
to  perspiration  and  dirt,  immune  to  oil  and  grease,  and  is 
cleaned  by  wiping  off  with  a  damp  cloth.  Production  of 
I'lcxiin  was  necessarily  limited  during  the  war.  but  i-  now- 
increasing.  The  present  color  range  is  wide — 120  beauti- 
ful shades — and  many  smart  designs  in  fabrics  are  being 
woven. 

Used  in  Varied  Models 

The  handsome  appearance  of  Plexon  and  its  durability, 
together  with  the  unusual  facility  with  which  the  material 
can  be  handled,  makes  it  of  particular  interest  to  top 
ranking  designers  who  are  always  eager  for  g<xxl  new 
fabrics.  The  hat  collections  by  such  style-setters  as  John- 
Frederics,  Hattie  Carnegie,  Florence  Reichman  and  Rose 
Saphire,  each  bears  the  unmistakable  stamp  of  its  creator: 
and  is  made  in  as  great  a  variety  of  models  and  style-  a- 
though  many  different  types  of  fabrics  had  been  used. 

The  pleasure  of  working  with  Plexon  is  attested  to  by 
these  master  milliners.     Hattie  Carnegie  says  "/'/r.n>n  is 
wonderful  to  work  with  .  .  .  you  can  make  anythiii. 
of  it." 

John-Frederics  likes  Plexon  because  ".  .  .  it  -tay-  put 
and  doesn't  stretch  ...  it  isn't  affected  by  steam." 

Florence  Reichman  says,  "Plexon.  in  a  myriad  of  ways 
replaces  the  straw  fabrics  that  we  have  used  for  so  many 
years  .  .  .  because  it  requires  no  sizing  and  does  not  turn 
color  when  exposed  to  the  sun  .  .  .  and  it  is  not  affected 
by  water.  It  is  pliable  and  drapeable  and  light  in  weight 
.  .  .  It  has  really  been  fun  to  work  with  a  material  tliat  i- 
in  such  perfect  accord  with  a  new  world  wliieli  more  and 
more  will  depend  on  man-made  material-  to  supplant  na- 
ture's resources." 

Easily  Formed 

Mi--  Saphire  think-.  "/'/<MOII  i-  exc|in-ite  to  work   with. 
It  folds  and  drapes  to  the  ex.iet  foini  you  wi-h  to  give  it 
and  can  be  molded  anil  M<x-ke<l.     I'  v  to  work  with 

that  it  is  actually  a  time--avitiir  material.     In  all  nr 
perience  with  straw  cloths,  which  this  approximates,  I  have 
toiind  none  that  can  e<|ua!   I'lfxon  for  Ix-auty.  lustre  and; 
(jiiick  response  to  the  needle."  >  M> 

46  NOVEMBER   1!U« 


YOU  HAVE  A 


DIFFICULT  PROBLEM 


IN  PRECISION 


BO* 


We  invite  you 

to  use  the  facilities  of  the 

INTERNATIONAL  PLASTIC  HARMONICA  CORP. 

makers  of  the  famous  MAGNUS 

all-plastic  harmonica. 


INTERNATIONAL  PLASTIC   HARMONICA  CORPORATION  .  44  OICKERSON    STREET  •  NEWARK  4,  N.  J. 
NOVEMBER  1946  PLASTICS  47 


jo* 


f     SOLVENT 

1<te*l 


SHATTERPROOF       SEAMLESS 
FEATHERLITE       IMPRINTED  DURING 

MANUFACTURING  PROCESS 


INJECTION  &  EXTRUSION 


CH 


We  do  custom  molding  in  volume 
for  clients  who  value  quality  plus 
production  performance. 


INJECTION 

MACHINES 

with   capacity 

up   to   22  oz. 


Use 


containers 


.  U.  S  P«l.  OH. 


for    DRUGS          TOOLS          SUNDRIES 
GAUGES       HARDWARE       NOVELTIES 
DENTAL    and    SPORTING    GOODS 
SEEDS  -  -  INSTRUMENT  PARTS       LUBRI- 
CANTS     OINTMENTS  and  SPECIALTIES 

CLEARSITE      The  Safety  Base  Plastic 


EXTRUSION  MOLDING 

To  customer's  specification,  e.g., 
ROD,  TUBING,  TRIM,  etc.  MANU- 
FACTURERS OF  VICTOSEAL  one 
of  America's  outstanding  Vinyl 
materials. 


WtiU  to  CONTAINER  DIVISION 


Write  to  INJECTION  MOLDING 

&  EXTRUSION  DIVISION  - 


CELLUPLASTIC  C(]RPORATIOII 


PLASTIC     CON  TAI  NERS 

A  NO 

PLASTIC     PKODUC  TS 


SO      AVENUE     L 


NEWARK     S      N      J 


rot*  orfici-tio  nun  AVI 


48 


ff*f..lftTf  <  * 


M>\  i.MHKl 


4* 


a  •=   -s 


o>  js    o    « 


SG  £    «  3 


Mir 


V 


»  wW-. 


Entire  villages,  in  miniature,  can 


by  community  planners,  using  new  type,  vinyl  building  sets 


Building  Scale  Models 


COMBINING  the  features  of  a  creative  toy  with  the  func- 
tional qualities  df  scale-modeling  equipment,  a  build- 
ing set  which  is  being  introduced  by  Du  Page  Plastics  Co., 
Chicago,  utilizes  vinyl  plastics  throughout.  This  article 
gives  a  detailed  description  of  the  components  and  ba>ic 
steps  in  the  construction  of  these  miniature  buildings. 

The  idea  was  originally  conceived  by  Emil  Ibach  and  de- 
veloped with  tin-  assistance  of  A.  Kip  Livingston,  his  part- 
ner in  the  Du  Page  company.  Mr.  Ibach,  who  was  at  one 
time  a  building  contractor,  had  formed  a  hobby  of  making 
miniature  houses  and  other  structures,  and  it  occurred  to 
him  that  scale  models  which  could  be  assembled  and  disas- 
sembled in  the  same  manner  as  are  construction  set  toys  for 
youngsters,  would  have  distinct  advantages. 

A  long  period  of  planning  and  experimentation  preceded 
production  of  the  finished  set,  however.  The  idea  called  for 
use  of  a  lightweight  material  which  would  be  attractive  and 
colorful,  would  not  swell  or  warp,  and  could  easily  be  kept 
clean  so  as  to  retain  its  fresh  appearance  after  excessive 
handling.  Several  materials  were  tried,  and  discarded  for 
various  reasons,  and  eventually,  rigid  vinyl  molding  pla- 
tics  were  decided  upon  as  being  most  suitable  for  the  pur- 
pose, because  the  material  can  be  injection  molded  to 
exceptionally  close  tolerances,  has  excellent  dimensional  sta- 
liility,  low  mold  shrinkage  providing  high  dimensional  ac- 
curacy and  size  control,  low  percentage  of  water-absorption, 
resistance  to  chemicals,  is  non-flammable  and  non-toxic. 

Many  Application*  Foreseen 

A  wi'lr  iisr  of  the  building  sets  is  foreseen  by  their 
makers,  in  industrial,  home,  and  community  planning.  Not 
only  houses,  but  scl-  -id  a  \.u 

other  structures  can  be  built  in  miniature  to  make  visual  an 
architect's  plans,  the  ideas  of  potential  hotnr-buildrrs,  dec- 


orators, industrial  planners,  and  others.  It  is  also  possjhl 
for  an  architect  to  build  the  scale  model  of  a  project  aiv 
then  draw  his  plan  from  the  completed  model.  Tin-  |>.nt 
are  scaled  J4"  to  the  ft.  this  proportion  bavins,'  been  de 
cided  upon  by  the  designers  of  the  set  as  being  in  confoi  mir 
with  most  architects'  plans. 

Engineers  and  manufacturers  can  build  an  entire  factof] 
in   miniature,  with   provisions  for  machine  locatioi 
working  space  determined  by  this  means  before  actual  build 
ing  is  begun.     Communities  may  be  planned  in  this  fashiol 
and  the  zoning,  traffic  and  other  details  thus  worked  ou 
in  advance.     And  in  the  fields  of  visual  education, 
craft,  and  table-top  photography,  the  manufacture 
plastics  building  sets  feel  that  there  are  outstanding 
tunities  for  use  of  the  diminutive  construction  pan- 
an  educational  toy,  they  believe  that  it  will  be  aeon, 
tbnsiastic  acceptance. 

"•ricks  and  Sticks" 

The    sets   are   comprised   of   tiny   plastics    "bricks"   am 
smooth,  slender  dowels  made  of  wood  in  various  lent 
The  full-size  bricks  are  14"  long  by  %"  high  atK 
wide,  and  there  are  half-size  bricks  for  "e\cnmi:  "it"  v 
next  to  doors  or  windows,  accurately  titling  corners. 
permitting  full  bricks  to  "lap"  wherever  possible.     11 
,d-o  curved,  or  quarter-arc  brick-,  for  rounded  structure! 
The  dowels  are  .130"  in  diam.     A  baseboard  which  is  part 
each  set  is  made  of  MasoHitc  perforated  b\  i  hoi 

.125"  in  diam  ami    ;  '  apart,  in  an  overall  criv 

pattern. 

First  step  in  construction  of  a  miniature  structun 

.11  of  dowels  ;l,  required  by  the  individual  plan,  in 
the  holes  in  the  ba-rlnurd  I  :u  h  of  the  tiny  molded  brie 
contains  holes  .1  15"  in  diam.  which  have  a  raised  collar  < 


PI.  AST  it'.S 


NON  KMHKK   194 


Insertion  of  dowels  in  perforated  baseboard  is  first  step  in   construction  of  a  miniature  building.  Plastics  bricks  are 
slipped  over  dowels  in  prescribed  order,  with  doors,  windows  and  other  parts  added.   Placing  of  roof  is  fina^  procedure 


Adaptability  of  plastics  to  a  widening  range  of  applications  is 
further  evidenced  in  their  utilization  in  a  new  type  of  scale- 
modeling  set,  which  has  a  variety  of  uses  in  structural  planning 


With  Vinyls 


8  W 


, 

plastics  Associate  Editor 


:  underside  and  a  recessed  collar  at  top.  The  bricks  are 
[>ped  over  the  dowels  and  collars  interlock,  holding  pieces 
:urely  in  place  as  construction  progresses.  There  are  two 
les  in  the  full-size  bricks,  one  in  the  half-size.  A  notched 
*ss,  or  slot,  is  molded  into  either  end  of  the  full-size 
ck  to  fit  doors  and  windows.  Specially  designed  half- 
cks  are  provided  to  hold  shutters  in  place. 
Rafters,  ridgepole  and  roofing  are  also  of  rigid  vinyl ;  the 
gepole  is  in  sections  which  dovetail  together,  and  fits  into 
X)ves  in  rafters,  locking  them  firmly  in  place,  and  the 
sties,  roof  "shingles"  have  molded  projections  on  under- 
es  which  set  into  the  rafter  grooves. 

Fhe  roofing  components  supplied  differ  with  the  particu- 
type  of  building  model  to  be  erected.  They  include  parts 
flat  roofs;  coping  roofs;  and  hip  (or  slanted)  roofs  with 
res.  Chimneys,  as  in  actual  construction,  are  built  up 
m  the  foundation. 

\pparently  nothing  has  been  overlooked  in  the  planning 
these  building  sets — there  are  chimney  caps,  window 
tes,  shutters,  and  various  other  parts,  all  injection  molded 
the  Du  Page  company's  plant  in  Lombard,  Illinois.  Clear 
yl  is  used  for  windows,  and  for  "glass  bricks"  simulating 
«e  used  in  ultra-modern  home  building.  The  opaque 
cks  are  furnished  in  either  red  or  white,  while  doors, 
ifing  material,  window  boxes  and  other  parts  may  be  of 
e,  green,  red  or  white.  Sets  do  not  include  landscaping 
terial. 

Mien  completed,  the  structures  are  strong  and  durable; 
y  can,  however,  easily  be  disassembled,  so  that  the  parts 
reusable  any  number  of  times  and  provide  a  wide  va- 
ty  of  models,  thus  making  it  possible  for  planners  to 
ninate  guess-work  by  rebuilding  as  many  times  as  neces- 
y,  with  the  miniature  components,  to  attain  the  effect 
ired  in  ultimate,  actual  building. 


The  sets  are  sold  in  kits,  ranging  from  the  small  set  which 
contains  materials  for  constructing  one  building,  to  a  set 
which  holds  components  for  five  different  structures.  Each 
kit  contains  a  blueprint  of  directions,  and  a  construction 
and  idea  handbook.  Supplementary  parts  are  obtainable  in 
accessory  kits,  each  containing  a  specific  number  of  the  tiny 
building  components.  According  to  the  company's  plans,  all 
kits  are  to  be  available  in  leading  department  stores  through- 
out the  country. 

Based  on  sound  construction  principles,  these  Du  Page 
building  sets  supply  a  further  illustration  of  the  variety  of 
uses  to  which  plastics  can  be  put.  END 


The  scale  model  of  a  Cape  Cod  type  house  and  garage  provides 
a   clear  idea  of  what   the  actual  finished  home   will   look   like 


DVEMBER  1946 


51 


Cellulose  acetate  enclosures  used  by  the  Division  of 
Education.  Los  Angeles  County  Museum,  permit  perfect 
view  of  sturfed  bird  specimens,  while  also  protecting 
them  from  damage  and  rough  handling  by  students 


The  cases  are  formed  in  jigs;  overlapping  ends  and 
top*  are  temporarily  bonded  with  acetone,  pending 
electrical  welding.  Metal  rod  is  used  to  clamp  over- 
lapped ends  in  place  as  solvent  effects  a  jointure 


Plastics  Cases 


For  Museum  Specimens 


IN"   (IKI)KK  to  protect  valuable  mounted  specimens  of 
California  hirdlife  from  rough  handling  by  children  in 
ornithology  classes,  tin-  l.os  Angeles  County  Museum  now 
encloses  each   specimen    in   a   transparent,   welded   case  of 
l.umarith  l.-Klfi. 

I'.eforc  adoption  of  this  practice,  tin-  museum  experienced 
heavy  losses  in  its  feathered  educational  displays,  which 
are  loaned  to  public  schools.  The  taxidermy  was  of  siu-h 
fidelity  that  children  were  prone  to  fondle  the  mounted  birds, 
and  some  months  ago  it  In-came  apparent  that  a  barrier  nin-t 

•   up. 

Russell  J.   Smith,  curator  of  the  division  of  education, 
ordered  experimentation  with  several  materials.     An  en- 
•  •nt  having  100%  visibility  and  easy  cleanability.  was 
sought.     The  enclosure  had  also  to  be  practically  unbreak- 
able. HOD- flammable,  light  in  weight  and  easy  to  fabricate. 

I'o  meet  these  requirements  Karl  Suchomel,  musetin 
artist,   started  working  with   sheet-  of  l.umarith   (cellulose 
"OJ"  and  .IKI.V  thick.     These  sheets,  supplied  by 
Transparent  Products  Co.,  Los  Angeles,  lend  themselves  to 
rapid,  simple  fabrication.     The  cases  are  formed   in  jigs, 
where  overlapping  ends  and  the  top  an-  joined,  temporarily, 
with   McKesson  &  K»hhin«  acetone.     I- ventiially.  the  join- 
.ire  welded  with  a  specially  designed  electric  soldi-ring 
iron. 


Children  now  may  study  the  stuffed  birds  at  close  rang 
but  although  they  may  handle  the  light,  tough  cases  at  w  il 
they  cannot  touch  the  fragile  contents.  One  specimen  ma 
endure  indefinitely,  traveling  from  school  to  school  as  use  0 
the  plastics  cases  has  eliminated  the  need  for  cxtensU 
duplications  previously  made  by  the  museum's  taxiderm 
department  to  provide  replacements  for  numerous  mine 
study  pieces. 

An  ordinary  hinged  knife,  of  the  type  used  by  photogrt 
pliers,  is  used  to  cut  the  sheets.  Sidewalls  are  shaped  aroufj 
5-ply  birchwood  bases.  An  overlap  of  "4"  to  '  /'.  dependin 
mi  si/e  of  the  case,  is  marked  off  when  the  sheets  arc  movi 
to  another  jig  for  a  brush  application  of  the  transnarcj 
acetone  for  temporary  bonding  of  the  vertical  sidew^ 
jointures. 

Two  Lutnarith  strips,  %"  or  J4"  wide,  are  bonded  wi 
acetone  at  top  of  the  sidcwall  as  reinforcements.  After  fjT 
inner  strip  i-  applied,  an  untrimmcd  sheet,  with  extendiol 
selvage,  is  sealed  with  acetate  to  form  a  roof.  I'se  of  tB 
wooden  base  inside  the  structure  .ml-  m  establishing  t|| 
o\al  shape. 

The  outside  reinforcing  strip  next  goes  into  place,  as  ' 

structure  is  rotated   -lowly  on  a  turntable        \   weight   s(al 

ili/cs  the  unfinished  I'a-e  during  the  process.     The  base  thf 

i  (  ,,nliniied  «tt  f<i<1f  89) 


I*  I.  \STI1 


Sconce  i*t 


When  GERING 

"carries  the  ball" 

Fast  Action 

and 

Sound  Thinking 
Score  for  You 

In  plastics,  as  in  football,  there 
are  barriers  and  shifting  obstacles 
to  avoid  or  evade  that  require 
generalship  and  resourcefulness. 


What  to  do  in  rejuvenating  molding  pow- 
ders to  the  goal  of  prime  dependability 
and  utility,  and  how  to  do  it  with  unusual 
economies  is  an  important  ingredient  in 
GERING  teamwork  and  technique. 

Your  so-called  "waste",  converted  by  the  Gering 
touch  to  vitalized  usefulness,  is  restored  to  an 
exceptional  degree  for  re-use. 


Write  us  regarding  your  requirements 
Telephone:  CRanford  6-2900 


NOVEMBER  1946 


oj  ^IlLarjic  in    C//ter»HO/mis/te 
PLASTICS 


converson 


53 


Ktrumenls  mode  by  musician  BUIy  G!o-~  ran  -<  * 
tsom  o  .grand  piano  10  a  full  sel  oi  clarinets, 
all  soid  lo  possess  ciear:  true  tonal 


Fashioned    oi    ci^ai    octi 
coospass    and    prouacioi    has 
tot  draftsmen,  home.   oHic*.   a 
Easy  to  use.  it  can  be  cairied 


Th«  smartly  modem  desiyn  ol  o   ploi  '-,,  i 
precision-mode    by    Airiold    Biiihoit    JLltt^ 
fribules    o    striking    and    <itsunct>  ••      to 
hciimonize   with   today's  home  dec&rohvi     ^> 


Blade-long   handle,   oi   dear   poiy3tyren< 
ouiding  edge  far  adjustable  sleel  blade 
botd  knits"  made  by  Hain 


COLOR  is  Added  to 
Plastics  Tableware 


The  soft,  pastel  shades  ol  "Melmac" 
dishes  impart  tone  harmony  to  a 
breakfast  table  setting.  This  eye- 
appealing,  lightweight  tableware 
is  available  in  several  different 
shades  designed  to  blend  with  any 
decorative  scheme,  and  will  add  a 
cheery,  colorful  note  wherever  used 


PLASTICS  tableware  in  rainbow  hues,  introduced  during 
recent  months  by  Watcrtown  Mfg.  Co.,  Watertown, 
Conn.,  has  proved  to  be  an  attractive  innovation.  Molded 
of  American  Cyanamid's  Melmac  (nielamine  formaldehyde  > 
in  four  pastel  shades — rose,  blur,  green,  and  yellow — this 
colorful  Watertown  Ware  supplements  the  ivory-toned 
dishes  in  which  the  line  was  initially  introduced. 

Melaminc  dishes  are  not  exactly  new;  the  ivory-colored 
-«-t-  were  used  extensively  by  the  U.  S.  Navy  during  the 
war,  and  have  received  favorable  postwar  response  in  the 

imer  market,  according  to  the  report. 
1  his  tableware  is  not  intended  to  replace  or  to  compete 
with  fine  china  or  porcelain  for  formal,  dinner-table  use; 
it  does,  however,  possess  distinct  advantages  for  such  use 
as  picnicwarc,  on  houseboats,  for  outdoor  dining  in  gen- 
eral, infant  feeding,  and  breakfast  or  dinette  sets.  In  the 
first  place,  mrlamine  tableware  will  not  chip,  crack  or  craze 
iitnlcr  ordinary  conditions  of  \IM- ;  <  HinUTs  department 
store.  New  York,  has  advertised  it  as  being  "almost  un- 
breakable." It  is  beat-resistant,  so  that  it  can  be  washed 
and  sterilized  in  automatic  machines;  it  is  odorless,  taste- 
less, and  light  in  weight,  and  it  is  inexpensive.  This  com- 
bination of  properties  makes  it  highly  practical  for  the  pur- 


listed  above,  and,  in  addition,  gives  it  possibilities 
for  use  in  restaurants,  cafeterias,  hotels,  trains,  boat-. 
schools,  kindergartens,  and  institutions  such  as  hospitals, 
etc.  A  "high-chair"  set  for  infants  features  an  8-inch  plate. 
a  I io\\  I.  and  an  8-oz  milk  mug. 

Its  lack  of  decorative  qualities  has  been  felt  by  its  makers 
to  be  a  handicap   (most  people  apparently  preferring  the 
patterned  decoration   which   generally  adonis  chinav 
This  problem  has  In-eti  tinder  consideration,  and   it    is   IM-- 
lieved  that  a  satisfactory  solution  will  exentiially  IK-  worked 

Milt. 

The  attractiveness  of  the  new  pastel-toned  ll'utrrti>-cn 
ll'urf.  however,  seems  hardly  to  require  cmlx-llishnient. 
The  colors  are  soft  and  harmonious,  and  blend  gracefully 
with  each  other.  A  20-piece  set  consisting  of  four  each 
of  dinner-size  plates,  bie.-nl  and  butter  plates,  cups,  snuc<  rflj 
and  deep  liowls,  combines  the  four  shades.  One  plate  is 
yellow,  one  blue,  one  rose,  and  one  green,  and  this  is  con- 
tinued through  the  other  -,M,.,.|I  pieces  of  the  set.  so  that 
a  rose-colored  cup  may  rest  m  a  saucer  of  the  same  shade, 
or  may  1«-  combined  with  the  green,  yellow,  or  bine  saucer. 
and  the  other  pieces  may  be  similarly  matched  or  combined, 
i  (  nH/iHi/ri/  nn 


I*  I.. \STI1  '.«•• 


\()\  KMHKK    ]<Mfi 


is/STRONG? 


producf  rr 


PHE  impact  strength  of  a  producf  may  be  the  final  test  of  whether  or 
not  it  will  do  the  job  for  which  «  was  designed.  Here  at  Watertown  we 
don't  guess  at  a  product's  strength  —  scientific  instruments  measure  it 
exactly!  On  the  testing  machine  shown  above,  an  Izod  impact  test  is  being 
conducted  on  a  molded  shape  tb  determine  its  impact  strength.  This  is  only 
one  of  the  many  plastic  tests  and  services  you'll  receive  from  Watertown's 
designers,  engineers  and  chemists  when  you  call  upon  them  to  help  you 
plan  new  products  and  prgduct  improvements. 

SEE  HOW  OUR  COMPLETE  CUSTOM  MOLDING  SERVICE  WILL  SOLVE  VOUR  PLASTIC  PROBLEMS 

Writ*  THE  WATERTOWN/MANUFACTURING  COMPANY,  Wotertown,  Connecticut. 
BRANCH  OFFICE-Cleve/and.   SALES  OFFICES- 
New  York,  Chicago,  Detroit  Milwaukee 
and  Hawaii.  / 


NOVEMBER  1946 


PLASTICS 


57 


E> 


American  Plastics  offers  beautiful  decorative  effects  in  casein  buttons  and  novelties 

JCnow  Your  Caseins 

Part  II.   Applications  for  this  material  include  its  use  in 
finishing  paper  and  leather  ,  in  adhesives,  as  a  paint  base 


Dr.    Ljeorae  ^A/.   Kjroln 


ner 


CASEIN  FIBERS  were  first  produced  commercially  in 
Italy  anrl  were  called  Lanital  (Italian  wool).  In  this 
country  numerous  groups  have  worked  on  the  development, 
principal  among  whom  art-  the  I'.  S.  Department  of  Agri- 
culture, both  in  the  Bureau  of  Dairy  Industry  and  at  the 
•n   Regional  Research   laboratory,  and  the  National 
I>airy  Products  Company.  The  latter  is  in  production  on  a 
:  fiber  known  n*.  .  I  mint  on  a  scale  reported  to  be  around 
5.000,000  lb  annually.     1  he  K.istern  Regional  Research  Lab- 
oratory has  announced  the  development,  on  a  laboratory 
scale,  of  a  casein  bristle  that  is  reported  suitable  for  re- 
placement of  the  non-available  long  hog  bristles  in  oil-paint 
brad 

Acid  caseins  are  used  for  fiber  preparation,  the  first  step 
IK-HII;  the  preparation  of  a  thick,  high  viscosity  alkaline 
-nlntii'ti.    ThU  is  forced  out  or  extruded  through  tiny 
holes  in  a  'Spinncrcttc."  under  tl  •   ~alt-and 

arid  water  solution,  much  the  same  as  viscose  in  the  produc- 
tion of  viscose  rayon.    The  acid  coagulates  the  casein  in 


PI, 


filler  form  and  these  fibers  (50  to  5000  fibers  are  spun  from 
the  spjnucrette  simultaneously)  are  then  .stretched,  further 
chemically    treated    (usually    with    formaldehyde 
other  tanning  agent),  and  dried. 

Properties  of  Casein  Fibers 

ein  fibers  have  many  good  properties  and  arc  finding 
useful  application,  but  they  are  not  wool  (even  though  Imth 
wool  and  casein  are  proteins  and  the  casein  itlxT  resembles 
wool  in  appearance  and  feel)  and  they  should  not  be  con- 
sidered a  wool  replacement  or  substitute.  They  arc  soft. 
good  heat  insulators,  somewhat  resilient,  felt  well,  and  take 
acid  dyes  readily  to  produce  beautiful  color  effects.  When 
dry.  their  tensile  strength  is  about  70-80';  that  of  wool,  but 
when  wet.  falls  to  around  20%  that  of  wool.  In  consent; 
they  are  used  in  mixture  with  wool,  cotton,  or  rayon  in 
textile  fabrics  in  such  amounts  as  to  impart  desirable  dec- 
orative or  physical  properties  without  seriously  impairing 
the  strength  and  durability  of  the  fabric.  They  are 


NO VI  MBKR   15)46 


eutd,  Sfode  Sfaafte 

Extrusions 


Yardley  has  in  stock  a  large  number  of  extru- 
sion dies  for  both  rigid  and  elastomeric  thermo- 
plastic materials. 

Before  ordering  a  special  extrusion  why  not 
check  our  stock  shapes.  If  we  don't  already 
have  what  you  require,  our  complete  die  and 
mold  shop  can  supply  your  needs. 

•^•^^••^•••••••^^••^••••••••••••H 


A  R  D  L  E  Y 


142   PARSONS   AVE. 


COLUMBUS   15.   OHIO 


d.ri    o*    SARAN.    CELLULOSE   ACETATE,    BUTYRATE.    POLYSTYRENE.    STYRALLOY   and   VINYLS     Al.o   Injection    and    Camprxilan    Maldfef. 


NOVEMBER  1946 


PLASTICS 


59 


Assortment  of  buttons  and  buckles  made  of  casein  evidences 
attractiveness  of  these  products  from  this  protein  material 


used  100%  as  inner  linings  for  garment--,  when-  tlu-ir 
strength  is  adequate  and  their  insulating  properties  are  use- 
ful, and  in  mixture  with  animal  fur  for  felt  hat-. 

Intensive  research,  both  by  i  invcrntnental  and  private 
agencies,  is  being  conducted  at  the  present  time  to  develop 
so-called  synthetic  protein  fibers  having  specific  useful  prop- 
erties, not  only  from  casein,  but  also  from  such  other  pro- 
teins as  soybeans,  corn,  peanuts,  egg  white,  and  chicken 
feathers.  It  is  anticipated  results  from  this  work  will  es- 
tablish these  fibers,  as  has  been  the  case  with  plastic-.  <m 
their  own  and  not  as  substitutes  for  other  established  fillers. 

Casein  Adhetives 

The  adhesive  value  of  proteins  has  long  been  well  known, 
as  evidenced  by  the  widespread  and  long  use  of  animal  glue, 
derived  from  the  hides  and  bones  of  animal-.  Milk  curds 
have  been  used  as  adhe-ive-  as  far  hack  into  antiquity  a- 
therc  are  records,  but  the  large  scale  n-e  of  casein,  as  such, 
as  an  adhesive  in  industry  date-  from  World  War  I.  At 
that  time  there  was  need  of  a  light  weight  material  of  ade- 
quate strength  for  airplane  propeller  blades.  Wood  lami- 
nate-, with  the  alternate  plies  a--emtiled  cross  grained  and 
bonded  with  animal  glue,  were  tried,  but  the  glue  lacked 
necessary  water  resistance.  It  was  found  that  a  ca-ein  ad- 
hesive containing  lime  in  the  mixture  became  water  insol- 
uble upon  drying,  thus  giving  a  bond  of  materially  improved 
water  resistance.  For  the  airplanes  of  that  day.  this  was 
adequate,  and  propellers  cut  from  casein  bonded  plywood 
were  extensively  used. 

The  advantages  of  a  product  such  as  plywood,  which  had 
all  the  good  features  of  wood  yet  was  stronger  I  the  c: 
grain  of  alternate  plie-  producing  a  unit  with  no  grain  i  and 
capable  of  easily  being  made   into  panels   wider   than  any 
board,   caused   the   development    of   a    large    new    industry, 
which  today  is  playing  an  im|x>rt;mt  part  in  the  production 
of  structural   materials.    Acid  caseins  are  used  m  alkaline 
water  solutions,  along  with  lime,  and  numerous  other  om 
stitiient-.   such  as  sodium   silicate,  sodium  thioiide.  copper 
or  manganese  -.tit-,  etc       I  lie  adlic-ivc  is  applied  by  glue 
spreaders,  and  the  plies  arc  assembled  in  a  pie—  and  ! 
until  set-up  or  clamped  and  held  until  the  ca-cin-liin 
action   is 

I'lywiHxl  bonded  with  casein,  although  more  water  i 
ant   than  that  Ixmdcd   with   animal   glue,   i-   not   water   and 
mold  resistant  enough  for  exterior  ;    n-e   wh- 

will  com.-  in  continual  contact  with  water  For  interior  u-e 
it  has  proved  \.-ry  n-cfiil.  and  its  light  weight  ami  strength 


render  it  valuable  for  use  in  forms  into  which  concrete  is 
poured.  The  development  of  the  synthetic  resin-  urea-for- 
maldehyde and  phenol-formaldehyde  as  plywood  bonding 
agents  have  made  possible  plywood  applications  ca-ein 
bonded  plywood  could  not  fill,  but  casein  and  soyU-an 
bonded  plywood  continue  to  be  used  in  the  larger  volume 
because  of  their  lower  cost.  It  has  been  proposed  to  use 
casein  and  dried  blood  (I".  S.  Pat.  2.368,4661  in  mixture 
with  and  extender  for  phenolic  resin  in  plywood  bonding. 
Reduced  time  and  temperature  of  cure  and  material  cost 
reductions  are  claimed  to  result  without  serious  impairment 
of  stability  and  water  resistance. 

Casein  adhesives  are  usually  found  on  the  market  in 
dry  powder  form,  with  all  the  solid  constituents  present  in 
proper  proportions.  To  prepare  for  use,  the  powder  is 
merely  mixed  with  the  right  amount  of  water  and  stirred 
until  perfectly  smooth  and  uniform.  The  chemical  reaction 
In-tween  the  casein  and  lime  is  slow  enough  at  usual  room 
temperatures  to  give  good  working  life  to  the  adhesive  alter 
it  has  been  mixed,  but  of  course  the  adhesive  in  the  glue 
pot,  as  in  the  glue  lines  between  the  plies,  will  set-up  in 
time  and  become  insoluble  in  water.  In  this  respect  ca-cin 
adhesives  differ  from  animal  glues  and  more  nearly  re- 
.semble  the  synthetic  resins. 

Casein  Paints 

The  same  casein-lime  reaction  that  make-  ca-ein  the 
most  stable  protein  adhesive  also  makes  it  the  best  protein 
base  for  the  so-called  cold  water  paints.  These  are  largely 
used  for  interior  wall  decoration  and  for  the  improvement  in 
cleanliness  and  effective  light  in  factory  room-.  The  im- 
proved "calcimine"  used  on  home  walls  and  which  is  some- 
times represented  as  "washable,"  is  made  with  casein  binder, 
as  are  the  finishes  in  white  or  light  cream  colors  periodically 
applied  to  the  walls  of  most  efficient  and  well  lighted  fac- 
tories. Application  may  be  by  brush  or  spray  gun.  Drying 
is  by  evaporation  of  the  water,  during  which  the  casein-lime: 
reaction  goes  to  completion  and  the  paint  is  -et.  The  func- 
tion of  the  casein  is  that  of  binder,  to  fix  and  hold  the  pig- 
ment of  the  mixture  firmly  and  evenly  in  place  on  the  wall 
surface.  The  reaction  with  lime  render-  the  ca-cin  water 
iii-olublc;  hence  in  this  sense  the  finish  i-  washable.  It  is 
more  resistant  to  water  than  the  earlier  calcimine-,  which 
relied  upon  glue  or  starch  for  binders,  but  related  wa-liings 
with  water  will  loosen  it  as  will  the  application  of  any 
moderately  strong  caustic  solution. 

\ciil  ca-ein-  are  u-ed  in  casein  paints,  which  are  pi  • 
like  the  adhesives  as  mixed  jxiwdcr-  requiring  only  admix- 
ture with  the  pro]»cr  amount  of  water  for  use.     Bc-iilc-  the 
ca-ein.  lime,  and  pigment,  these  mixture-  usually  contain  a 
picscrvativc   to  discourage  liactcrial  action  on  the  r 
agents   designed    to    improve   the   water    resistance    beyond 
that  of  the  simple  casein-lime  mixture,  and  agents  to  reduce 
the   surface   tension  of  the   tilm   surtace  alter   the   paint   has 
been  applied,  so  any  brush  marks  or  other  irregularities  will 
smooth  out  In-fore  drying.     These  are  usually  light  oil-,  -uch 
a-  pine  oil  or  oil  of  citronclla.  u-ed  in  quantities  so  small 
they  may  IK-  incorporated  with  the  dry  powdered   mixture 
without    appreciable    physical    effect.       I'.ecan-e    of    tlv 
oi-i  of  all  -olid  ingredients,  the  simplicity  of  mixing  proce-l 
dure  (the  dry  powder  is  usually  mixed  by  grinding  constit- 
uents together  in  ball  mills  i  and  the  fact  that  the  vein 
water,  cold  water  paints  are  comparatively  low   in  c.i-l.     It  is 
therefore  practical   to  apply  them  frequently   with   re-tilting  j 
brightening  and  freshening  of  the  room-       I  he  died  of  this  ; 
U|H>II   morale   is  definitely   favorable. 

in  has  IOIIK  Ix-cn  used  in  finishing  leather  for  ahin 
If   hides   and    skin-    had    perfect    -nrfa 
when  brought  to  the  tanneries  and  if  the  gram  sitrf:i 
hair    side   after    removal    of   the    hair  I    stitfered    no   damac 
(('annulled  on  f,i,/. 


60 


I*  I.. 1ST  I  4  s 


N0\  KMMK.K    I!' I 


delivery? 


AT  MIDLAND  IT'S  FASTER  THAN 
A  CAT  CAN  HAVE  KITTENS! 


This  wall  socket  hobbed  cavity  by  Midland  incorpo- 
rates two  narrow  "T"  projections  raised  3/16  inches 
above  the  cavity  surface.  By  using  hobbed  cavities  of 
this  type  in  place  of  the  conventional  insert  cavities, 
all  unsightly  parting  lines  were  eliminated  and  in 
addition  to  improving  appearance,  the  hobbing  was 
accomplished  at  only  a  fraction  of  the  cost  of  cavity 
duplication  by  machining  methods. 


Yes,  actually!  It  takes  a  cat  nine  weeks — and  on 
most  hobbed  cavity  jobs  we  do  a  lot  better  than 
that!  Our  skilled  craftsmen,  our  machining, 
engraving  and  hobbing  equipment  are  working 
constantly,  accurately  on  a  schedule  that  means 
delivery  of  hobbed  cavities  in  a  matter  of  weeks 
— not  months.  Whenever  you  order  from  Midland 
you  are  assured  the  kind  of  accurate,  uniform, 
perfectly  finished  hobbed  cavities  that  only  skill 
and  experience  can  provide. 

So  if  limited  molding  capacity  and  long  quoted 
delivery  are  holding  you  back,  grab  the  problem 
by  its  neck  and  bring  it  to  Midland  where 
delivery  is  shaved  to  a  cat's  whisker. 

For  a  clear  picture  of  our  equipment  and  our 
know-how,  write  for  a  copy  of  "Shaping 
Tomorrow  Today."  Better  still,  send  your 
blueprints! 


MIDLAND  DIE  AND  ENGRAVING  COMPANY 

1800  W.  BERENICE  AVENUE      •       .       •       CHICAGO  13,  ILLINOIS 

Makers  of  Plastic  Molds    •    Die  Cast  Molds    •    Engraved  Dies    •    Steel  Stamps    •    Hobbings    •    Pantagraph  Engraving 


NOVEMBER  1946 


PLASTICS 


61 


Compression  Mold  Design 


Fig.   1.     Heat  transfer  on  deep  draw  molds  should  be  channeled 

Part  III.  Mold  heating,  flash, 
threads,  undercuts,  side  holes, 
are  some  cavity  design  problems 
met  in  producing  unusual  parts 


(John    Lj. 


STEAM  C HAH Ntt. 


CAVITY 


C<  IMPRESSION  molds  require  heat  in  order  that  th 
compound  can  cure  and  set  up  rigid  enough  to  b 
ejected.  While  hand  molds  receive  their  heat  from  th 
press  platens,  the  semi-automatic  mold  should  have  MUM 
provision  for  heating  built  into  the  die.  The  mo>t  comino 
method  of  heating  molds  is  the  use  of  steam,  and  both  to 
and  bottom  of  the  die  should  be  drilled  with  sufficient  chat 
nel>  to  permit  good  circulation  of  the  steam  and  even  di- 
tribution  of  the  heat  to  the  various  cavities.  On  most  mole1 
the  main  plates  are  drilled,  but  on  deep  draw  jobs  it  i-  advi- 
able  to  supply  several  rows  of  channels  in  the  cavity  ha 
and  the  punch,  if  large,  should  not  depend  on  tran-ier 
heat  from  the  top  plate,  but  should  be  channeled  I  Fig.  1 

Steam  channels  should  be  close  together.     About 
center-to-center  is  desirable,  and  four  inches  should  be  con 
sidered  the  maximum  spacing.     The  location  of  heatm 
channels  is  especially  important   in  molds  to  be  used   i 
molding  urea  materials  as  uneven  heating  can-e-  burning 


OUT 

4 


IN 


ooo  o 


8 -CAVITY  MOLD  IN  AND 

OUT   AT  BACK  OF  PRESS 


O 


o 
oto 


o 


O' 

o 


o 
o 


IS -CAVITY    MOLD    IN    AND 
OUT     AT    BACK  Of  PRESS 


OUT  . 


:t 


OOO 


•PLU6-IN  LINS 

-PLOW  of  STEAM 


Z-CAVITY  MOLD   IN  AND 
OUT  AT  BACK  Of  f>#CSS 


Fig.  4.    Precautions  in  the  design  of  guide  pins 

vhich  is  very  apparent  on  the  pastel  colors.  For  this  type 
)f  work  dimension  B  should  not  exceed  two  times  dimen- 
Bon  A  (Fig.  2). 

Care  should  be  taken  in  laying  out  heating  channels  to 
iee  that  the  inlet  and  outlet  are  not  located  so  as  to  inter- 
ere  with  the  stripping  mechanism  of  "the  press  or  the 
:lamping  slots  when  the  die  is  mounted.  Channels  must 
llso  be  located  so  that  they  do  not  interfere  with  knockout 
>r  guide  pin  holes,  and  this  consideration  must  be  kept  in 


Fig.  5.     External  threads  molded  by  split  rings 

mind  when  laying  out  the  cavities  on  a  multi-cavity  mold. 
Fig.  3  shows  several  patterns  for  cavity  and  steam  chan- 
nel layouts. 

The  two  halves  of  the  mold  should  be  lined  up  by  means 
of  guide  pins.  These  are  usually  four  in  number  and  of 
ample  size,  at  least  three-quarter  inch  diameter  and  some- 
times one  inch  or  an  inch  and  a  half,  depending  on  the 
size  of  the  mold  and  the  accuracy  required  in  alignment  of 
(Continued  on  page  95) 


80TTOM  HALf 
~Of  MOLD  IH 


BOTTOM  HALF  Of 
MOLD  SLIDES  OUT 


FOa  UNSCROVIN6 


BOTTOM  HALF 
/  Of  MOLD 


MOVING  t>0ESS 
^  PLATEN 


Fig.  6.    To  permit  easier  access  for  unscrewing  Fig.  7.    Split  molds  are  used  for  molding  some  parts 

NOVEMBER  1946  PLASTICS  63 


Extruding  laminated  coating  material  onto  interior  surfaces  ol  a  sheet  iron  acid  valve.    Right,  valve  after  application  ol 
coating.  Non-seizure  between  coated  valve  and  valve  seat  testifies  to  surface  hardness  of   material   after   polymerization 

How  PHENOLIC  RESINS 
Combat  Corrosion 

New  successes  in  the  field  of  an ti -corrosion  treatment  of  metals  are 
now  being  made  possible  with  the  use  of  plastics  materials 


PLASTICS  materials  are  leading  the  way  to  new  suc- 
cesses in  tin-  field  of  ant i -corrosion  treatment  of  metals. 
Since  earliest  recorded  history,  man  has  been  combating 
corrosion  by  the  application  of  protective  surface  coatings. 
The  early  Chinese  used  tung  oil,  and  Egyptian  records  make 
repeated  mention  of  linseed  oil  as  a  protective  medium. 
I  Vspite  this  historical  record,  corrosion  prevention  was  an 
empirical  science  until  early  in  the  twentieth  century,  when 
synthetic  finish  materials  were  developed.  Since  that  date, 
lung  strides  have  IK-CD  made.  But  we  still  have  far  to  go. 
The  annual  corrosion  bill  for  American  industry  alone  is 
estimated  at  more  than  $2,000,000,000. 

James  l.ithgow.  of  Los  Angeles,  who  has  been  working  in 
the  anti-corrosion  field  for  20  years,  has  developed  a  series 
of  formulations  of  phenolic*  dispersed  in  alcohol  which  are 
proving  effective.  It  has  been  found  that  any  application  of 
importance  requires  the  individual  attention  and  cx|>criencc 
of  a  trained  corrosion  engineer  for  best  results.  It  is  a  high- 
ly specialized  field,  and  must  cope  with  widely  varying  con- 
ditions. A  coating  that  will  serve  well  under  sprciiic  me- 
chanical and  chemical  conditions  may  have  to  IK-  modified 
when  it  is  used  lor  other  purpose*.  The  l.ithgow  company 
therefore  does  not  sell  its  products  directly  but  only  through 
its  nwn  engineering  service. 

The  materials  it  use*  today,  all  modified  phenolic*,  con- 
sist of  an  U.K.  Scries  of  spray  coatings,  an  I..  Scries  of 
g*  that  may  Ix-  sprayed  or  applied  by  laminating  or 
extruding,  and  a  phenolic  impregnating  coni|M>und  for  *a|. 
xaging  all  type*  of  \>"-  -ig*.  I  he  impregnation 

:<|ilication  of  the  coating  materials,  is  carried 
•  •tit  by  the  company  in  its  own  shop*,  in  equipment  specifical- 
igned  for  tin*  ty|«-  of  work. 

The    plastics    .  ...iting    material*    employed    have    the    ail- 


vantage  that  it  is  only  necessary  to  clean  the  metal  prior  U 
application.  No  binders,  primers  or  inhibitive  uudeicnat; 
are  required,  as  they  arc  by  organic  finishing  matei  i.ds 
Thus,  the  entire  thickness  of  the  coating  serves  the  -m 
purpose  of  corrosion  prevention.  The  degree  of  pro' 
provided  permits  articles  to  be  manufactured  from  iron  .-m< 
steel,  rather  than  the  more  costly  inert  metals  such  as  stain 
less  steel,  aluminum  or  magnesium. 

H.R.  Series  Sprayed  On 


the 


64 


I*  I.. \STI1  S 


NOVKMKKK 


specimens,  coated  with  an  equal  thickness  of  ordinary  baked 
enamel,  wore  through  after  1500  cycles.  In  shear  tests, 
jsing  a  Taber  Plastic  Shear-Hardness  Tester,  the  coating 
ivas  several  hundred  per  cent  superior  to  any  baked  enamels 
ivailable. 

In  another  laboratory  magnesium  panels,  coated  with  the 
.-arious  H.R.  Series  plastics,  withstood  5000  hr  of  exposure 
n  a  regulation  salt  spray  cabinet.  Most  ordinary  paints 
md  enamels  will  give  less  than  72  hr  protection  under  the 
;ame  conditions. 

1.  Series  Have  New  Qualities 

The  L.  Series,  insofar  as  application  is  concerned,  offer 
something  new  in  plastics  coating.  They  may  be  applied 
either  by  spraying,  laminating  or  extruding,  and  in  thick- 
icsses  ranging  from  0.10"  to  3/16".  Like  the  H.R.  Series, 
:he  basic  constituent  of  the  L.  Series  is  a  phenolic,  but  a 
iller  is  employed  to  provide  the  desired  characteristics. 

Three  modifications  of  the  L.  Series  laminated  coatings 
ire  available.  One  modification  exhibits  high  acid  re- 
sistance, another  high  caustic  resistance,  and  the  third 
•esistance  to  high  temperatures.  The  high  temperature  coat- 
ng,  under  highly  acidic  conditions,  will  give  maximum 
>rotection  at  temperatures  in  excess  of  500°  F. 

Next  to  corrosion  resistance,  the  outstanding  quality  of 
he  laminated  coating  is  said  to  be  its  resistance  to  impact. 
V  500  Ib  casting  dropped  five  ft  onto  the  bottom  of  an 
lectroplating  tank  dented  but  did  not  break  the  plastics 
:oating.  A  test  panel  coated  %"  thick  may  be  beaten  with 
L  heavy  hammer  without  injury  to  the  laminated  material. 

Application  of  the  L.  Series  may  be  in  single  coat  form, 
>r  in  multiple  coats  until  the  desired  thickness  is  obtained, 
lence  the-  designation  "laminated."  When  excessively  thick 


coats  are  required,  such  as  are  used  to  protect  the  interior 
surfaces  of  large  acid  vats,  the  material  may  be  extruded 
onto  the  clean  metal  surface,  using  a  putty  knife  or  similar 
tool. 

Despite  recent  advances  in  foundry  practice,  a  good  many 
castings  are  still  produced  that,  while  sufficiently  strong,  are 
extremely  porous.  This  porosity  makes  such  products  as 
valves,  pipes,  and  similar  fluid-carrying  components  utterly 
useless.  In  the  past  (and  currently)  a  silicate  impregnation 
process  was  used  to  reclaim  these  parts,  but  this  process  was 
never  overly  successful.  Here  again  plastics  prove  their 
superiority. 

Using  a  phenolic  impregnating  material,  pressurized  and 
polymerized  in  specially  designed  apparatus,  the  Lithgow 
company  claims  to  return  from  90  to  98%  of  porous  casting 
rejects  entirely  fit  for  use.  Here  again  the  modifying  ma- 
terials, pressure,  and  polymerization  temperatures  are  a 
trade  secret. 

In  an  actual  test,  a  single  large  bronze  valve  designed  to 
operate  at  125  psi  fluid  pressure  leaked  badly  at  less  than  50 
psi.  After  impregnation,  no  leakage  occurred  at  400  psi.  In 
another  instance,  a  batch  of  600  defective  Dural  castings 
were  submitted  for  treatment.  After  treatment,  98%  of 
the  castings  were  acceptable.  Both  the  Army  and  Navy  will 
accept  castings  that  have  been  reclaimed  by  the  plastics 
impregnation  process. 

Men  familiar  with  the  work  are  certain  that  anti-corrosion 
applications  are  destined  to  offer  the  plastics  industry  a  huge 
new  outlet  for  materials.  Unlike  various  manufacturing 
processes  that  require  molding  and  extruding  operations, 
anti-corrosion  work  is  not  limited  by  the  size  or  scope  of 
the  project.  They  may  be  applied  with  equal  effectiveness 
on  objects  from  peanut  size  to  railroad  bridges.  _  END 


PARTS   FOR   ELECTRICALLY   ILLUMINATED    DIAGNOSTIC 
INSTRUMENTS  MOLDED  BY  AUBURN  FOR  WELCH  ALLYN 


AUBURN'S 

Plastics  Gallery 

Auburn  molded  plastics  have  served  American 
industry  for  the  last  70  years.  Auburn  "know- 
how"  is  the  product  of  that  experience  ...  it  is  the 
extra  value  you  get  when  you  choose  Auburn  as 
your  custom  molder. 


AUBURN  BUTTON  WORKS,  INC. 

fOUNDID   IN    1176   •   AU1URN,  NIW  YOIK 


AUBURN    ENGINEERED    PLASTIC    PRODUCTS 

Compreiiion,  Transfer,  and  Injection  Molding 
Automatic  Rotary  Molding  for  Matt  Production 
Extruded  Vinyl  or  Acetate  Tubes  and  Shapes 
Cellulate  Nitrate  Rods,  Sheets,  Molded  ParU 
Complete  Mold  Sho 


iVOVEMBER  1946 


PLASTiCS 


65 


EXTRUSIONS 

Take  on  JVe  w  Jobs 


Complexity  of  shapes  now  possible  with  extrusion  process 
indicates  further  opportunities  /or  important  applications 


THE  intricate  nature  of  some  of  the  profiles  now  being 
fabricated  have  expanded  the  opportunities  for  plastics 
extrusions.  Continued  practice  has  led  to  the  economic 
production  of  many  complex  shapes.  Sections  now  being 
fabricated  Avould  a  few  years  ago  have  been  deemed  too 
difficult  to  undertake.  These  developments  indicate  that  the 
field  still  holds  many  large  opportunities  for  important  ap- 
plications. 

Progressive  steps  which  have  brought  this  about  include 
improved  plastics  materials,  better  die  production,  conveyor 
shaping,  curing,  post-machining  and  the  application  of  laws 
governing  hydraulics. 

In  addition,  the  extruder  has  discovered  that  it  is  better 
to  alter  an  unextrudable  profile  than  to  undertake  one  which 
is  beyond  the  realm  of  present-day  technique.  Obviously, 
such  procedure  would  be  handled  only  in  consultation  with 
the  design  engineer,  for  extrusions  are  seldom  complete 
items  in  themselves.  Usually  they  are  parts  of  assemblies 
and  must  fit  into  the  scheme  of  the  whole. 

For  this  reason,  the  extruder  constantly  finds  himself 
confronted  with  the  problem  of  fabricating  a  part,  which  re- 
sembles something  already  made  of  metal,  glass,  fiber,  rub- 
ber or  other  materials. 

The  wide  variety  of  available  plastics  and  the  accumulated 
knowledge  pertaining  to  extrusions  enables  him  to  overcome 
most  of  these  difficulties  with  possibly  a  few  changes  in 
design.  These  changes  however  must  be  of  such  nature 
that  a  suitable  working  part  be  furnished. 

At  an  incentive  the  plastics  fabricator  has  the  advantage 
of  being  able  to  produce  a  precise  item  embodying  durability, 

!.|x-;il  and  perhaps  novelty.     In  addition,  the  pi. 
material  which  he  selects  may  possess  resistance  to  attacks 
of  weathering,  chemical-.,  acids  atid  alcohol  far  higher  than 
that  of  the  previously  used  substances. 

The  Plastic  Process  Co.,  Los  Angeles,  of  winch   1 
Kotkin  is  owner,  has  introduced  its  own  methods,  developed 
some  of  its  own  machinery,  engineered  new  designs,  fabri- 
cated its  own  products  arid  engaged  in  experimentation  to 
overcome  seemingly  inMtnm mutable  problems. 

For  instance,  a  table  edge.  1"  wide  with  a  }&"  tenon  for 
.11  in  tin-  table  wood,  due  to  its  unusual  shape  in- 


volved fabrication  of  several  dies  before  a  suitable  one  wa 
made.  It  was  necessary  to  experiment  with  heats,  coolin 
and  the  position  of  the  conveyor  in  relation  to  the  die  orifice 
Tenite  II  (H2)  (cellulose  acetate  butyrate)  eventually  \va 
utilized  for  this  job  because  of  the  material's  resistance  t 
moisture,  its  stability  and  its  attractive  appearance. 

A  curve  in  the  grooved  vertical  edge,  extruded  horizon 
tally,  was  controlled  by  depressing  the  conveyor  3"  beloi 
the  height  of  the  die.  The  depression  was  effected  13"  fron 
the  orifice.  Higher  elevations  caused  the  material  to  flatten 
while  lower  elevations  exaggerated  the  curvi 

Thus,  any  tendency  to  warp  was  avoided,  and  the  >• 
was  held  to  a  nearly  uniform  width.   A  variable  of  phi-  o 
minus  5%,   indiscernible  optically  and  permissible   in  thi 
case,  was  attributed  to  slightly  fluctuating  heat-  in  <!<• 
cylinders. 

Heats,  however,  were  held  close  to  350°  F  for  tin- 
cylinder,  300°  F  for  front  cylinder  and  400°  F  for  the 
Higher  temperatures  thinned  the  material  to  a  point  when 
the  profile  became  unstable.  The  die  heat  produced  a  hij-l 
gloss,  acting  like  a  lubricant  which  caused  the  material  ti 
flow  smoothly  through  the  orifice. 

Heat-  for  this  operation  were  approximately  those  us 
for  the  majority  of  Plastic  Process'  extrusions  of  the  -.in 
dimensions.     Larger  extrusions  require  greater  heat,  and 
smaller  ones,  less  heat.    I'stial  heats  employed  by  Theodore 
W.  Kerr,  production  engineer,  are:  Rear  cylinder  34n    to 
400°  F;  front  cylinder  .'50°  to  350"  F;  die  350°  to  450°  F.| 

To  maintain  a  right-angled  position  for  the  table  edg 
tenon,  this  portion  was  run  on  the  conveyor  between  a  -eric 

'"  rollers.    These  were  8"  apart,  three  on  a  side,  spac 
evenly  but  .not  opposite  each  other,  for  a  distance  of 
The  nearest  roller  was  20"  from  the  die. 

Curing   Variable  Thickness  Section 

( 'uring  of  this  c\tni~ion  with  its  varying  thicknesses 
-••ntrd   another    problem,   eventually   solved   by   trial 
I  he  cure  in  the  thicker  tenon  was  accelerated  by  fine 

vhich  blew   straight  down.     Purposely,  no  air 
ilinvted  on  thinner  parts  of  the  profile. 

Shape  el.  uch  as  grooves  in   the   tenon 

grip  the  wood   mortise  and   two  parallel  channels  for 


|| 


PLASTICS 


NOVKMKKK   HI  16 


For  Versatility  in  Plastic  Molding 

[  you  can  Depend  on  GRIGOLEIT 


For  19  years  we've  supplied  many  nationally 
prominent  manufacturers  with  parts  and  trim  for 
their  products.  The  versatility  of  our  facilities  and 
our  molding  experience  enable  us  to  create  unusual 
design  or  standard  plastic  items. 
For  reasonably  early  availability,  we  offer  an  ex- 
tensive "standard"  line  of  handles,  knobs  and 
other  parts  for  stoves,  furniture  and  household 


appliances;  also  a  large  "stock"  line  of  closures 
for  foods,  drugs  and  cosmetics. 
We  also  maintain  a  complete  custom-molding  serv- 
ice in  thermo-plastic  and  thermo-setting  plastics. 
Operating  our  own  metal  and  tool  shops,  we  are 
able  to  insure  perfect  blending  of  plastics  and 
metal. 

Write  for  1946  Catalog 


THE    GRIGOLEIT   COMPANY 


744    E.   NORTH    STREET  DECATUR    8O,   ILLINOIS 

NOVEMBER  1946  PLASTICS  67 


appeal,  were  accomplished  by  the  die.  A  die  orifice  nearly 
twice  the  size  of  the  section  was  developed  after  trials  and 
errors.  The  speed  of  the  conveyor  drew  the  extrusion  to 
>ize. 

Machining  operations  for  the  original  die  orifice  con- 
sumed 23  work  hours.  Twenty  more  hours  were  expended 
in  trials  on  the  machine  and  in  enlarging  the  orifice  to  its 
ultimate  dimension-. 

Intensive  Cooling  for  Complex  Profile 

Extrusion  of  a  cellulose  acetate  butyrate  holder  for 
changeable  theater  marquee  letters,  a  development  of 
Theater  Specialtic-.  I.»-  Angeles,  involved  specially  de- 
signed rollers  to  aid  in  establishing  the  shape  of  nine  pro- 
jections. These  legs  varied  from  J4"  to  5/16"  in  length, 
and  were  designed  to  hold  back-lighted  sign  letters  and  the 
,'l;t--  behind  the  letters.  To  stabilize  the  numerous  legs, 
rollers  were  grooved  in  exact  conformity  with  one  side  of 
the  complex  profile. 

Experimentation  showed  that  24  rollers  were  needed  in 
the  series.  Twelve  operated  above,  and  the  same  number 
below,  the  conveyor.  They  were  placed  opposite  each  other 
in  pairs,  spaced  2"  apart. 

To  produce  a  well-balanced  section,  cooling  was  expedited 
not  only  by  the  usual  air  jets,  but  by  every  auxiliary  blower 
which  could  be  brought  into  action  in  the  limited  curing 
area.  The  cure  thereby  was  effected  when  the  section  had 
traveled  3'  from  the  die. 

Hardening  was  further  accelerated  by  using  Tcnite  II 
(H5),  which  has  a  high  softening  point.  The  material  also 
was  chosen  for  its  service  in  the  out-of-doors.  It  stands  up 
in  a  wide  range  of  temperatures  and  is  highly  resistant  to 
moisture  absorption. 


Several  dies  were  tried  before  a  satisfactory  one  was  pro 
duced.  Eventually,  a  die  lOfr  larger  than  the  section  wa: 
adopted.  The  conveyor  was  run  proportionately  faster  thai 
the  extrusion  to  stretch  the  profile  to  the  required  dimensions 

Fabrication  of  the  initial  die  consumed  40  work  hours 
Subsequent  experimentation  to  develop  a  die  10rc  largei 
than  the  profile  required  60  additional  hours  on  the  machine 
and  in  the  die  shop. 

An  example  of  design  suited  both  to  performance  and  pro 
duction  is  the  firm's  transparent  channel  molding  for  mirroi 
and  picture  frames.  The  molding,  for  which  patent  ha- 
been  applied,  is  essentially  a  transparent  cellulose  acetat< 
veneer,  Tenite  II  (H2),  which  snaps  over  a  strip  of  decora 
live  fabric  or  paper,  laid  over  the  frame-wood. 

Naturally,  the  colorful  background  may  be  changed  at 
will,  as  it  becomes  a  simple  process  to  remove  and  replace 
the  plastics  covering.  Fabric  or  paper  Ix-tu-ath  the  molding 
may  match  draperies  or  wall  coverings,  or  may  be  chosen  to 
harmonize  with  the  color  scheme  of  the  surroundings. 

Protruding  from  the  molding,  a  flange  holds  the  picture 
glass  in  place.  The  same  flange  will  also  secure  another 
parallel  strip  of  identical  extrusion,  thereby  establishing  a 
plastics  rectangle  within  the  first  one.  In  this  manner, 
frames  of  extreme  width  may  be  assembled,  with  sometimes 
four  or  five  moldings  nesting  one  within  another.  By  add- 
ing strip  after  strip  of  molding,  massive  effects  may  he 
achieved. 

In  designing  this  plastics  section,  which  has  numenais 
grooves,  five  channels,  three  legs  and  two  beads,  care  was 
taken  to  provide  a  profile  which  lent  itself  to  accuracy  in  the 
extrusion  process.  The  two  vertically  extruded  U-L;S  \ve-re 
run  on  the  conveyor  between  rollers  to  establish  shades 
No  obstacle  was  presented  by  the  beads,  which  jut  from 
(Continued  on  page  87) 


OUR    SPECIALTY 

LARGE PARTS  INJECTION  M°ULDED 

OUR  ENGINEERS  ARE  EXPERTS  IN  ORIGINAL  DESIGN,  AND  WILL  ASSIST 
YOU  IN  WORKING  OUT  YOUR  SPECIAL  PROBLEMS  WITHOUT  OBLIGATION 


LATEST  EQUIPMENT  INCLUDES  j  2-16  oz.  •  M2  oz.  •  1-9  oz.  and  2-4  oz.  PRESSES 

Manufacturing:  Vacuum  cleaner  parts,  hypodermic  syringes  and  caps, 

coat  hangers,  hair  curlers,  soap  boxes,  tract  holders, 
tool  handles,  and  various  other  articles. 

For  complete  service  from  an  idea  to  a  manufactured  part,  call  or  write  to 


MAU1.&E&S  -  SPECIALISTS    IN   LARCE   CASTINGS 
273O    WEST    IZrn    ST..-  E  RI  E,  PENNA. 

PLASTICS  NOVKMHKR  194 


' 


PLASTICS 


Modifications  for  Preco  Press 

Preco  Incorporated 
Los  Angeles,  California 

The  manufacturer  of  the  Preco  Hydraulic  Press,  to  meet  a 
growing  demand  among  its  users  for  a  wide  range  of  production 
and  industrial  testing  uses,  has  developed  several  important 
modifications  for  the  press. 

The  Preco  unit  is  now  available  in  platens  measuring  8ft" 
by  12".  These  are  furnished  either  with  1500  w  electrical  heat- 
ing elements  which  give  fast  heat  acceleration,  or  for  steam 
heating.  Triple  platens  which  double  the  press  capacity  by  per- 
mitting work  to  be  inserted  above-  and  below  an  intermediate 
platen,  also  are  available  in  both  8"  by  8"  standard  size,  and  the 
new  size. 

Platens  can  be  supplied  for  steam  operating,  or  the  press  can 
be  supplied  to  hook  into  a  hydraulic  system (607) 


For  Injection  Molding 

Dorr-Patterson  Engineering  Co. 
Detroit,  Mich. 

250-ton  down  acting  4- 
column  press  has  a  12" 
stroke  to  which  is  attached 
a  hydraulically  actuated  in- 
jector for  plastics  molding. 
Press  is  operated  by  a  2- 
pressure  dickers  hydraulic 
system  in  conjunction  with 
a  prefill  system.  This  is  said 
to  permit  rapid  stroke  at 
low  pressure  and  a  holding 
pressure  during  curing  cy- 
cle without  an  excessive 
amount  of  electrical  power. 

Transfer  of  heat  from  the 
molds  is  dispelled  by 
grooved  steel  plates  bolted 
to  the  moving  platen  and 
lower  bolster. 

An  assembly  consisting  of 
a  plastics  injector  within  a 
2-section  frame  is  mounted 
on  wheels  that  travel  on  a  tube  track.  This  unit  is  moved  in 
and  out  of  the  die  by  a  fabricated  steel  differential  cylinder 
mounted  on  the  front  side  of  the  press. 

In  operation,  the  press  first  comes  down  and  closes  the  die  at 
a  given  pressure.  The  injector  then  contacts  the  mold  and  be- 
gins to  fill  the  cavity.  When  injector  pressure  overcomes  in- 
jector holding  pressure,  electric  power  to  injector  motor  is  shut 
off.  When  molded  parts  have  been  vulcanized  for  the  required 
period  of  time,  injector  is  retracted  from  the  mold,  press  is 
opened  and  molded  parts  removed  from  die.  This  reverse  pro- 
cedure may  be  automatic  or  semi-automatic (608) 


Forming-Drawing  Presses 

Indiana  Foundry,  Machine  &  Supply  Co. 
Marion,  Indiana 

Two  new  machines  developed  for  use  in  the  molding,  draw- 
ing, swaging  and  forming  of  thermoplastic  sheet  materials  of 
varying  thicknesses,  are  compressed  air  actuated  double  acting 
cylinder  type  units  controlled  by  double  action  foot  valve.  Speed 
of  press  closure  is  variable,  dependent  upon  easy  manipulation  of 
foot  valve  control. 

The  No.  420  press,  24"  by  24"  in  size,  is  equipped  with  a  7" 
diam  steel  mandrel  mounted  to  the  cylinder  piston  with  proper 
hole  settings  drilled  for  mounting  the  male  die  plunger.  Ad- 
justable arms  mounted  to  the  mandrel  are  guided  by  heavy  ma- 
chined vertical  posts. 

The  No.  624  press  is  said  to  be  particularly  adaptable  for 
accommodating  large  dies  used  in  the  forming  or  drawing  of 


large  sheet  areas,  with  the  slower  commensurate  press  action  re- 
quired. Size  is  48"  by  24".  This  model  has  a  steel  movable 
platen  mounted  to  the  cylinder  piston  and  guided  by  four  heavy 
machined  vertical  posts. 

Both  units  have  a  normal  working  pressure  of  from  75  to  100 
psi.  Normal  capacity  of  No.  420  is  Y*  ton,  while  that  of  No. 
624  is  one  ton (609) 


New  Resaw  Attachment 

The  DoAll  Company 
Minneapolis  4,  Minn. 

A  new  Resaw  attachment 
for  use  on  the  company's 
Zephyr  Model  36  bolts  onto 
the  column  of  the  handsaw, 
and  when  not  in  use  swivels 
out  of  the  way  so  that  the 
saw  can  be  used  for  other 
applications. 

Heavily  constructed  for 
positive  feeding  and  vibra- 
tion dampening,  it  has  a 
variable  speed  drive  which 
allows  the  operator  com- 
plete control  over  the  rate 
of  feed  ranging  from  0  to  30 
ft  per  min. 

During  full  capacity  of 
the  machine,  accuracy  of  the 
attachment  is  such  that  the 
variation  from  absolute 
squareness  in  cuts  is  less  than  0.002". 

This  unit  is  operated  electrically  on  4  feed  rollers.  A  calibrated 
wheel  indexes  cuts (610) 


For  Induction  and  Dielectric  Heating 

Induction  Heating  Corporation 
New  York  3,  N.  Y. 

A  recent  development  especially  designed  to  meet  the  need  of 
laboratories  for  a  rapid  and  dependable  source  of  heat  for  a  wide 
variety  of  heating  applications,  the  Tlicr-iiinnic  M-285C  electronic 
heating  generator  is  a  single,  dual-purpose  unit,  suitable  for  both 
induction  (metal)  and  dielectric  (non-metal)  heating  operations. 
Two  separate,  interchangeable  oscillator  sections — one  for  each 
type  of  heating — are  provided  with  the  unit.  Changeover  from 
one  section  to  another  is  accomplished  by  merely  removing  one 
section  and  replacing  it  with  the  other.  The  induction  oscillator 
feeds  into  a  radio-frequency  output  transformer,  while  the  dielec- 
tric oscillator  feeds  through  coaxial  cables  to  heating  electrodes. 

A  few  of  the  applications  for  this  high  frequency  generator 


To  simplify  for  our  readers  the  task  of  obtaining 
detailed  information  regarding  the  new  products,  proc- 
esses and  trade  literature  described  herein,  plastics 
offers  the  prepaid  postcard  inserted  here. 

Keeping  up  with  every  latest  development  in  one's 
field  is  a  "must."  Speeded  production,  and  the  com- 
petitive drive  toward  lower  manufacturing  costs  require 
that  all  avenues  leading  to  a  solution  of  these  prob- 
lems be  explored  thoroughly. 

Each  item  in  this  section  is  keyed  with  a  number, 
which  should  be  entered  on  the  postcard,  to  expedite 
identifying  the  exact  product,  process  or  publication 
about  which  information  is  desired. 


NOVEMBER  1946 


I'LASTl  CS 


fi9 


when  operating  as  a  dielectric  heating  unit  include:  preheating 
and  polymerizing  of  plastics  ;  wood  gluing  and  laminating  :  textile 
processing ;  evaporation  of  liquids ;  rapid  and  uniform  heating 
for  producing  desired  chemical  reactions i  <>1 1  i 


Temperature  Record 

Weston  Electrical  Instrument  Corporation 
Newark.  New  Jersey 

Available  in  two  mod- 
els. _V7M  and  221" ,  the 
Ma.r-Min  is  claimed  by 
its  manufacturer  to  fill 
the  need  for  a  low-cost 
device  which  will  pro- 
vide an  accurate  record 
of  high  or  low  tempera- 

^sw  V^B^  lures  on  chemical  equip- 

^^taK^^  ment,  ovens,  etc..  as  well 

(•H^HI  as    in   many   processing 

operations. 

The  new  all-metal  thermometer  has  an  auxiliary  red  index 
xvhich  is  manually  set  by  a  finger  knob  which  protrudes  from 
the  center  of  the  scale  glass.  When  a  record  of  the  lowest 
temp  is  desired,  index  is  placed  to  the  low  side  of  the  temp  point- 
er Pointer  will  move  index  to  lowest  temp  reached  during  any 
operating  period,  and  index  will  remain  at  that  low  point  until 
manually  reset.  For  record  of  highest  temp  reached,  procedure  is 
reversed 


Bag  Heat-Sealer 

Heat  Seal-It  Co. 
Philadelphia.  Pa. 

Recently  placed  on  the  market,  a  compact  sealing  unit  which 
is  designed  to  seal  all  types  of  thermoplastic  bags  and  envelopes 
is  power-operated,  and  has  an  automatic  mechanism  which  folds 
the  top  of  each  bag  as  it  is  sealed  in  one  fast,  simple  operation. 

More  efficient  hydraulic  type  of  thermostatic  heat  control  which 
azures  proper  temperature  at  all  times;  adjustable  shafts  which 
jicrmit  setting  of  feeding  level  at  most  convenient  height  from 
table  or  conveyor ;  f<x)t  pedal  clutch  control  that  moves  easily ; 
and  heavy  duty  gear  head  electric  motor,  are  said  to  be  some 
outstanding  features.  The  unit  is  equipped  with  8"  wide  crimp 
jaws  which  will  s,-al  hags  u|>  to  7  ' C>1.?) 


All-Purpose  Bench  Saw 

Flexsaw  Manufacturing  Company 

Port  Austin.  Michigan 

Especially  adapted  to  cutting  I'lf.ri- 
nliif.  l.ucilf.  and  other  thcrmoplas 
lic->,  a-,  well  as  wood,  the  new  bench 
saw  /• /i-.r.tdjc  is  claimed  to  be  ex- 
tremely accurate  in  producing  straight 
and  bevel  cut-off,  straight  and  bevel 
rip.  and  miter  and  compound  miter. 
It  can  also  be  used  for  polishing, 
grooving,  and  other  work. 

According  to  the  manufacturer,  six 
easily  made  adjustments  provide  lor 
rigid  positioning  of  the  blade  to  make 
almost  any  cut  |x>ssible. 

l-lf.rsiitc  is  capable  of  cutting  ma- 
il-rial  .?"   thick,   and   up  to    15"    wide. 

A  one  lip  motor  mounted  on  a  frame  supplies  power,  while  a 

flexible  shaft   drives  the  saw  which  eliminates   motor   interi'cr 

ence.  ... 


High  Temperature  Heating 

Blow  Knox  Division 
Pittsburgh.  Pennsylvania 

\  n«-w  method  of  high  temperature  heating,  the  /./,-,  <r,i-J'n/i,.r 
llfiiltmi  \\.tlfin.  combines  the  advantages  of  electric  and  /»•>:(•• 
Ihrrm  heating.  The  unit  is  self-mntained.  rcquin  s  >-..,  Uiilers. 
furnace  settings,  or  external  piping.  I'niform  heat  is  provided 
can  be  c|o.,|v  .  ..ntro||r,|  at  any  temp  ranging  between 
IIKI  K  and  700"  F.  ('onstrm  li..n  is  i-xplosion  resistant,  and  it  is 
claimed  that  the  unit  ran  be  used  with  safely  in  ha/ardous  at 
nvwpherr!* 


Literature  Review 


Protective  Strip  Coatings 

Tennessee  Eastman  Corporation 
Kmgsport.  Tenn. 

A  new   leaflet  titled  "Protective  Strip  Coatings  of   Kastman 
Cellulose  Acetate  Butyrate"  describes  in  detail  the  preparation 
and  application  of  continuous,  tough  coatings  to  be  used  for  the 
protection  of  metal  parts  against  corrosion  and  abrasion 
coatings  are  said  to  IK-  easily  stripped  from  coated  objects. 

Description  of  preparation  of  the  dip,  and  dipping,  som- 
equipment  and  ingredients,  and  prices  of  the  strip-coating  coni- 
l»>sitions  are  included ( <>!>> 


Micarta  Bearings  for  Steel  Mills 

Westinghouse  Electric  Corporation 
Pittsburgh.  Pennsylvania 

Special  features  of  Micarla  fabric  base  bearings,  their  1 
life,  increased  power  savings,  better  holding  of  gauge,  lev, 
justments  and  shutdowns,  and  increased  tonnage,  are  contained 
in  a  new  12-page  booklet.  No.  B-3776,    Performance  curves  and 
tables  are  used  to  describe  and  compare  the  four  grades  of  .Ui- 
carta,  and  recommended  applications  of  each  grade  are  listed. 
Photographs    showing    installation,    and   information    regarding 
ordering,  are  also  included ( '.17 


Non-Metallic  Basic  Materials 

Continental-Diamond  Fibre  Company 
Newark,  Delaware 

New   bulletin   GF  33  contains   valuable   information   . 
non-metallic  basic  materials  produced  by  the  company  :  /'IJMIOI 
Dilffto.    I'ulfaitl.    (V/nrim.   Micabond,   Dilfctcnf.     Of   especial 
interest  is  a  center  spread  comparative  chart  showing  e!< 
and     mechanical     properties    of    the     various     />i/,v/i>     sheet 
grades 


Jar  Mills  and  Rolling' Machines 

Abbe  Engineering  Co. 
New  York.  New  York 

Catalog  No.  63,  recently  issued,  contains  detailed  informal  in 
regarding  the  operation  ami  specifications  of  A  bin'  jar  mills 
many  other  models,  which  are  now  In-ing  produced  by  th 
company ( <>!'>) 


Die  Cutting  Process 

Accurate  Steel  Rule  Die  Mlrs 
New  York.  New  York 

A  process  of  die  cutting  which  has  recently  proven  successful 
in  many  industries  is  described  in  the  "Die  (.'utters  Manual" 
This  method  is  said  to  be  suitable  for  cutting  flat,  soft  and  semi- 
soft  sheets  to  any  flat  si/e  or  sha|ie.  Materials  now  lieing  sat- 
isfactorily cut  by  this  process  include:  plastics,  cork,  paper. 
leather,  and  many  others  .........................  <  :  <  i 


Multiple  Drilling  Machinery 

B.  M.  Root  Company 
York.  Pennsylvania 

Two  bulletins  covering  multiple  drilling  machinery    win. 
application  to  the  plasti.  s  industry  are  now   available. 

Hullflin  \i>.  "Nos  d.  si  riln-s  a  multiple  spindle  automat- 
semi-automatic  drill  with  an  K-ft  drilling  length.     This  n 
wa«  built  especially  for  drilling  plasi- 

Htillftin    '•  -hows  a  machine  which  is  used  with  mul- 

tiple spindle  drill  heads  for  Imring  holes  in  cluster*  at  one  time. 
Ilns    unit    performs    equally    well    on    plastics    nutcii:ils 

wood 


70 


NOVEMBER   i''Hi 


Sometimes  you  can  break  a  good  rule! 


It's  usually  a  wise  rule  not  to  plan  a  chicken  dinner 
before  the  eggs  are  hatched. 

But  not  always! 

If  the  "chicken  dinner"  represents  your  future,  and 
the  "eggs"  are  financial  nest  eggs— go  ahead  and  plan ! 

Especially  if  your  nest  eggs  are  U.  S.  Bonds — all  the 
War  Bonds  you  have  bought— all  the  Savings  Bonds  you 
are  buying.  For  your  government  guarantees  that  these 
will  hatch  out  in  just  10  years. 

Millions  of  Americans  have  found  them  the  safest, 


surest  way  to  save  money  .  .  .  and  they've  proved  that 
buying  Bonds  on  the  Payroll  Savings  Plan  is  the  easiest 
way  to  pile  up  dollars  that  anyone  ever  thought  of. 

So  keep  on  buying  Savings  Bonds.  Buy  them  at 
banks,  post  offices,  or  on  the  Payroll  Plan.  You'll  be 
building  real  financial  security  for  yourself,  your  family, 
and  your  business. 

Best  of  all,  you  can  count  your  chickens  before  they're 
hatched  .  .  .  plan  exactly  the  kind  of  future  you  want, 
and  get  it! 


SAV£  THE  EASY  WAY...  BUY  YOUR  BONDS  THROUGH  PAYROLL  SAVINGS 


Contributed  by  this  magazine  in  co-operation 
with  the  Magazine  Publishers  of  America  as  a  public  service. 


NOVEMBER  1946 


PLASTtCS 


71 


ENGINEERING 


By    LEWIS    WINNER 

Market   Research   Engineer 

New  Base  Plastics  and  By-Products 

Mounting  shortages  of  resins  and  the  resulting  increased  de- 
mand for  resin  scrap  have  prompted  the  development  of  many 
unique  reworking  processes  that  have  provided  effective  new 
base  plastics  and  highly  practical  by-products  such  as  cements. 
fillers  and  coatings.  Many  researchers  have  been  able  to  secure 
an  unusually  wide  variety  of  by-products.  Henry  T.  Neumann, 
N'ew  York,  for  instance,  has  developed  an  acrylic  resin-scrap 
process  \vhii-h  provides  organic  fillers  and  cements,  binders  and 
a  flexible  wear-resistant  lacquer. 

In  the  Neumann  method,  an  acrylic  type  resin  is  dissi>K,il 
in  a  volatile  organic  solvent  (benzene)  and  the  resulting  organic 
solution  applied  to  an  exposed  surface.  The  benzene  evaporates, 
dei»  >siting  a  horny  solid  substance,  which  is  softer  and  more 
flexible  than  the  original  material.  It  has  been  found  that  the 
concomitant  use  of  alcohol  accelerates  the  dissolving  action  ; 
methyl  alcohol,  butyl  alcohol,  cetyl  alcohol,  etc.  In  a  dissolving 
tr>t  JOOO  cc  of  ethyl  alcohol  and  7000  cc  of  benzene  were  used 
t.i  ilis>olve  about  half  a  kilogram  of  resin  scrap.  The  use  of  this 
type  solvent  for  454  gms  of  scrap  provides  a  molasses-type  solu- 
tion. 

The  solution  can  be  used  as  a  cement  or  as  a  bond  for  those 
plastics  which  may  be  softened  by  the  solvent.  It  can  also  be 
used  as  a  lacquer  which  may  be  either  clear  or  colored.  A 
change  in  the  proportions  of  alcohol  and  benzene  will  also  pro- 
vide an  opaque  or  semi-opaque  lacquer.  It  is  said  that  these 


lacquers  will  not  chip  or  break  even  when  the  surfaces  to  which 
they  are  applied  are  sharply  bent 

The  solution  may  also  be  used  to  fabricate  self-form-maintain- 
ing  fibrous  articles  from  paper  or  cloth.  In  the  production  of 
paper  articles  a  sheet  of  paper  is  coated  with  the  solution.  The 
surface  of  the  sheet  is  then  allowed  to  dry,  and  is  processed  for 
shape.  Zinc  chloride  can  be  used  as  the  retardant;  about 
to  2  hr  time  is  required  for  full  setting. 

Neumann's  process  of  dissolving  more  or  less  scrap  in  a  solu- 
tion, comprising  a  fixed  ratio  of  two  or  more  solvents  to  increase 
or  decrease  the  viscosity  of  the  solution,  is  contrary  to  ordinary 
practice.  Usually  a  greater  quantity  of  the  dissolving  agent, 
such  as  benzene,  is  added.  In  Neumann's  procedure  both  dis- 
solving and  accelerating  agents  are  added.  Neumann  >a\>  that 
he  has  found  that  where  the  ratio  between  the  alcohol  and 
benzene  is  varied,  the  transparency  of  the  deposit  product  varies 
correspondingly.  If  benzene  alone  is  used,  the  deposit  is  cU-ar 
and  transparent,  and  when  alcohol  is  used  in  a  ratio  of  two 
parts  out  of  nine,  the  result  is  still  a  clear,  transparent  product. 
However,  as  the  ratio  increases,  the  deposit  first  becomes  cloudy 
and  finally  opaque.  If  the  ratio  is  reversed,  using  ~(KXi 
alcohol  to  2000  cc  of  benzene,  a  highly  opaque  product  will  be 
produced. 

Color  in  Plastics 

Few  plastics  problems  have  prompted  such  active  reseai 
has  color.  The  two  forms  of  application  (direct  pigment,  and 
coating)  have  been  the  subject  of  many  debates.  One  school  of 
researchers  believes  that  the  use  of  pigments  throughout  the 
plastics  provides  the  most  effective  color  results,  while  the  other 
school  states  that  coatings  can  provide  the  same  color  control 
in  a  more  flexible  and  economical  manner.  A  recent  cellulose 
acetate  butyrate  coating  development  by  Charles  Bogin.  Terre 
Haute,  Indiana,  discloses  that  top  lacquer  coatings  are  more 
economical  than  the  expensive  pigments,  since  inex]>cnsive  tillers 
can  be  used  for  coloring. 

In  Bogin's  process,  for  coating  cellulose  acetate  pla-tir*.  tlic 


CONVERT    YOUR 


HYDRAULIC  PRESS  INTO  A 
VERTICAL  PLASTIC  INJECTION 
MOLDING  PRESS  IN  A  FEW  HOURS 

Unit  is  easily  removed  and  your  press  reconverted  to  a  hydraulic 
press.  We  require  the  dimensions  of  your  press  between  posts, 
front  to  back,  and  left  to  right,  daylight,  size  of  ram,  and  ram 
pressure  used. 

The  following  chart  will  show  the  capacity  of  your  press  at 
30,000  psi  injection  pressure. 


400  »o-  HY-ifffD  pren  wn*  36"«32'  /Voleni,  43'  da, 
light,  pi  if  on  type  rom  Conrt'tfd  into  a  34  of.  infection 
mocnme  of  o  coif  of  14500  'or  comp/cto  converiion. 


Ton» 

Or 

Molding  eree  tq.  tn. 

SO 

2 

7  to    20 

75 

3 

10  to    30 

100 

4 

IS  to    40 

ISO 

b 

20  to    60 

200 

8 

25  tc     8C 

250 

10 

30  to  100 

300 

12 

40  to  120 

400 

16 

60  to  180 

FLUID  POWER  AIR  OPERATED  PUMP 

185  gallon!  per  minute  et  200  pit   3000  pi!  accumulated   presiure   cuti 

in  et  200  poundt  automatically.    Unit  ii  in  e   it«el  cabinet  with  ell  th« 

controli  on   the   front   penel. 

4207  N.  Spauldinq  Avc. 
Chicago  18.  Illinois 


PLASTICS  MACHINERY 

FRED   M.   JERNT 


Independence    6145 


72 


\o\  KMHKK  nut; 


cellulose  acetate  butyrate  is  dissolved  in  a  solvent  mixture  that 
is  not  a"  solvent  for  cellulose  acetate — the  lower  nitroalkanes, 
ketone  compounds  and  the  lower  aliphatic  alcohols.  While  some 
of  the  various  materials  in  the  groups  are  solvents  for  cellulose 
acetate,  this  property  can  be  checked  by  adding  substantial 
amounts  of  diluents  such  as  butyl  acetate,  toluene  or  high  solv- 
ency naphtha.  Cellulose  acetate  butyrate  with  a  high  acetyl  and 
a  low  butyryl  content  is  preferred  by  Bogin. 

In  previous  methods,  nitrocellulose  and  ethyl  cellulose  have 
been  used  as  coatings.  These  materials  proved  to  be  unsatis- 
factory because  of  their  high  affinity  for  the  plasticizers  present 
in  the  cellulose  acetate  plastics.  This  undesirable  property  caused 
the  outer  coating  to  absorb  the  plasticizers,  resulting  in  a  tacky, 
soft  surface.  Cellulose  acetate  lacquers  were  also  tried,  but  did 
not  prove  successful  because  the  solvent  mixtures  incorporated 
in  the  lacquer  often  attacked  the  surfaces,  which  caused  wrin- 
kling. 

In  preparing  a  typical  coating  lacquer,  Bogin  used :  Cellulose 
acetate  butyrate  (acetyl  content  29%,  butyryl  content  15%),  8  g; 
1 — nitropropane,  25  cc ;  butyl  acetate,  25  cc ;  ethyl  acetate,  25  cc ; 
and  toluene,  25  cc. 

Bogin's  coating  films  are  said  to  withstand  aging  tests  at  a 
temperature  of  100°  F  in  an  atmosphere  having  humidity  of  be- 
tween 85%  and  95%.  The  concentration  of  cellulose  acetate 
butyrate  may  vary  from  4  to  10  gm  for  each  100  cc  of  solvent 
mixture  used. 

New  Vinyl  Chloride  Process 

A  unique  method  of  manufacturing  vinyl  chloride  has  been  de- 
veloped by  Herbert  M.  Stanley,  Tadworth,  England.  Stanley 
has  reacted  acetylene  and  hydrogen  chloride  at  an  elevated 
temperature  in  the  presence  of  a  mercuric  chloride  catalyst  sup- 
ported on  active  carbon  and  suspended  in  an  inert  liquid  diluent 
such  as  a  hydrocarbon  or  halogenated  hydrocarbon.  The  diluent 
provides  accurate  temperature  control  of  the  reaction  medium. 
Diluents  that  can  be  used  include  paraffin  oil,  di-isopropylbenzene, 
and  others. 

In  former  methods,  the  liquid  diluent  was  omitted.  Accord- 
ingly, the  reaction  was  strongly  exothermic,  causing  a  loss  of 
mercury.  Overheating  also  resulted,  producing  secondary  reac- 
tions. 

In  preparing  one  type  of  vinyl  chloride,  Stanley  used  thirty 
parts  of  active  carbon  impregnated  with  six  parts  of  mercuric 
chloride.  After  drying,  the  resulting  catalyst  was  suspended  in 
300  parts  of  di-isopropylbenzene.  The  suspension  was  then  filled 
into  a  packed  tower  and  a  mixture  of  acetylene  and  hydrogen 
chloride  fed  through  the  tower  with  temperature  maintained  at 
135°  C.  The  exit  gases  were  then  led  through  a  reflex  con- 
denser, yielding  sixteen  parts  of  vinyl  chloride  per  hr,  75%  of  the 
introduced  acetylene  being  converted  into  vinyl  chloride. 

Insulation  Characteristics 

When  plastics  was  first  applied  as  a  cable  insulation  many 
years  ago,  electrical  engineers  were  skeptical  about  the  electrical 
and  mechanical  stress  characteristics.  Extensive  tests  convinced 
the  engineers  of  the  acceptability  of  plastics  as  an  insulating 
medium,  and  that  it  provided  properties  that  were  comparable  to 
those  of  rubber  and  impregnated  insulation  covers.  Efforts  to 
improve  the  insulating  value  of  plastics  have  continued  and  today 
there  are  many  plastics  materials  which  are  considered  not  only 
equal,  but  superior  to  the  standard  type  of  insulating  coverings. 

An  excellent  example  of  this  progress  appears  in  a  recent  de- 
velopment by  Hugh  J.  Cameron,  Gary,  Indiana,  who  has  com- 
pounded polystyrene  and  polyisobutylene  to  provide  a  rubber-like 
coating  which  has  high  electrical-insulating  properties. 

Cameron  has  overcome  the  difficulty  of  combining  polystyrene 
and  polyisobutylene  by  using  differential  rolls  heated  to  at  least 
300°  F  by  steam  within  the  rolls.  Polystyrene  is  fed  through  the 
rolls  peripherally  to  cover  the  slower  roll  and  then  a  smaller 
amount  of  solid  polyisobutylene  is  added.  This  process  provides 
an  elastic,  rubber-like  sheet.  The  polystyrene  should  have  a  flow 
time  of  at  least  120  sec.  for  a  flow  of  1.5"  in  a  Rossi-Peekes 
plastometer  at  130°  C  and  at  pressure  of  1000  psi.  The  polyiso- 
butylene solid  should  have  a  molecular  weight  of  at  least  60,000. 

The  softness  of  the  sheet  depends  upon  the  proportions  of  the 
two  polymers  used,  and  upon  the  degree  of  polymerization  of 
each  of  those  polymers.  END 


Ingenious  New 

Technical  Methods 


To  Help  You  with  Your 
Reconversion  Problems 


NewTh read  Ring  Gage  Starts  Round 
Stays  Round  With  Every  Adjustment! 

Employing  a  new  principle  of 
design,  the  Woodworth  Thread 
Ring  Gage  closes  in  round  within 
.0002  maximum  after  .005  ad- 
justment. It  offers  greater  accu- 
racy and  stability  since  size 
adjustment  is  controlled  along 
thread  helix  angle.  Threads  are 
held  securely  in  alignment  after 
adjustment,  due  to  unique  adjust- 
ment means.  Wear  is  distributed 
over  full  circumference  for  all 
resettings,  thus  increasing  life 
of  gage. 

Positive  adjustment  makes  it  Woodworth  Thread  Ring  Gage 
almost  impossible  to  change  set- 
ting with  ordinary  knocks.  Posi- 
tive identification  by  a  green 
"go"  gage  and  red  "not  go" 
gage  saves  operator  time.  Alu- 
minum alloy  outer  body  cuts 
weight  in  half,  to  reduce  oper- 
ator fatigue  and  increase  sensi- 
tivity. 

To  also  reduce  fatigue  on  pre- 
cision jobs,  many  plant  owners 
make  chewing  gum  available  for 
workers.  Tests  show  that' the  act 
of  chewing  aids  in  relieving  ten- 
sion, which  is  often  the  cause  of 
fatigue.  These  tests  further  reveal 
that  chewing  Wrigley's  Spear- 
mint Gum,  for  instance,  helps 
workers  stay  alert,  thus  increases 
their  efficiency  to  do  more  accu- 
rate work. 

You  can  get  complete  information  from 

N.  A.  Woodworth  Company 

1300  East  Nine  Mile  Road 

Detroit  20,  Michigan 

AA-94 


NOVEMBER  1946 


PLASTICS 


73 


"Engineering"  a  Plastics  Toy 


Good    design    is    apparent    in    the    all-plastics    "Mickey 
Mouse  Viewer."  made  by  Craftsmen's  Guild.  Hollywood 


Ingenuity  and  careful  designing 
are  combined  in  production  of 
a  durable,  and  instructive  toy 


which  an-  joined  by  means  of  a  solvent  type  acetate  cement. 
A  flexible,  translucent  matte-finish  I.innaritli  sheet  replaces 
the  conventional  ground  glass  viewing  screen,  thereby  de- 
creasing cost  and  danger  of  breakage. 

The  lir>t  viewers  were  produced  with  an  ordinary  glass 
magnifying  lens,  but  in  an  effort  to  reduce  costs,  a  plastics 
lens  was  substituted.  The  first  plastics  lens  used  was  a 
transparent  acrylic,  but  it  was  discovered  that  the  plasti- 
ci/.er  employed  in  the  acetate  shell  would  diffuse  into  the 
plastici/er  in  the  acrylic,  clouding  the  lens  and  reducing 
its  brightness  and  efficiency.  It  was  then  discovered  that 
a  transparent  I.umarilli  lens  offered  the  solution,  since  the 
same  plastici/er  was  used  in  both  lens  and  viewer  body, 
and  no  diffusion  would  take  place.  The  lens  remained 
clear  and  bright  indefinitely. 

Production  of  Lens 

I'he  acetate  lens  is  produced  by  injection  molding.  Ten 
lenses  are  produced  in  a  single  shot.  The  high  finish  main- 
tained on  the  mold  surfaces  eliminates  the  necessity  of  post- 
molding  lens-grinding,  and  results  in  a  product  of  exception- 
al optical  efficiency,  clarity  and  resolving  power.  In  fact, 
it  is  superior  to  many  of  the  cheaper  glass  lenses  used  in 
this  type  of  product.  When  finished,  the  lens  is  approxi-  ' 
niately  ft"  in  diameter,  l/i"  thick  through  the  center,  and 
ta|H-rs  to  an  edge  thickness  of  1/16". 

Thus,  despite  the  low  cost  of  the  toy  product,  the  manu- 
facturers can  place  it  on  the  market  in  full  confidence  that 
it  will  equal  in  quality  similar  products  retailing  for  several 
times  the  price.  In  evidence  of  what  good  engineering  can  i 
accomplish  along  this  line,  the  Guild  is  now  called  upon  to 
produce  2J,(XX(  ft  of  16  mm  colored  film  strips  each  day.  to 
keep  pace  with  market  demands.  KND 


ECONOMICAL  and  sturdy  toys  are  a  "natural"  for 
the  plastics  industry.  But  in  successful  production  of 
these  simplified  products,  the  fundamentals  and  principles 
of  plastics  engineering  are  just  as  important  as  they  are  in 
production  of  more  highly  complicated  industrial  products. 
The  toy  maker  who  attempts  in  a  haphazard  fashion  to  turn 
out  plastics  "what-nots,"  will  in  most  instances  be  doomed 
to  early  failure. 

This  is  particularly  so  in  the  case  of  educational  or  semi- 
educational  toys,  ill-signed  to  stimulate  the  imagination  and 
to  train  the  minds  and/or  fingers  of  children  in  constructive 
work  and  thinking. 

\  variety  of  toys  of  this  type  have  been  produced,  but 
some  of  them  have  been  so  poorly  designed  or  so  carelessly 
constructed  that  their  life  in  the  hands  of  an  average,  active 
child  has  been  of  extremely  short  duration. 

Into  many  others,  however,  have  gone  ingenuity  and  de- 
signing backed  by  knowledge  and  experimentation,  to  pro 
duce  sturdy,  dependable   toys  which  could   withstand  hard 
•   and  continue  to  function  efficiently. 

Well-Engineered  Product 

<  Mie   example   of   a    well-engineered    yet    economical    all 
plastics  product   is  the  Mitkc\    WHIM,-   /  'irr.r;.  produced  hv 
the  Craftsmen's  <  iuild.   Hollywood.  Califoinia.     This  little 
gadget   retails  for  $1,  and  sales   volume   to  date   itnl 
what   can   be   accomplished    in   the   way   of   a    well  designed 
product. 

The  shell  of  the  viewer  is  of  colored  cellulose  acetate. 
reinforced  in  such  a  manner  that  a  single  half,  prior  i 
M-inhly.  will   withstand,  without  breaking,  the  weight   of  .1 
large  num.     The  shell  i*  injection  molded  m  two  halves. 


Body  halves  oi  viewer  are  molded  eight  at  a  time. 
Below,  lenses  which  are  produced  ten  to  a  single 
mold  shot  require  no  post-molding  lens-grinding, 
due  to  high  finish  maintained  on  mold  surfaces 


74 


i*  I.. 1ST  1 1  * 


NOVEMBER  lit  It; 


I 


Plastics  in  Aircraft  Interiors 

(Continued  from  page  17) 


highly  resistant  to  cigarette  burns  and  other  marring.  Lug- 
gage "as  well  as  cargo  compartments  in  the  DC-6  are  lined 
with  phenolic-impregnated  Fibcrglas-doth,  ideally  suited  to 
the  application  because  of  its  strength,  lightness,  and  im- 
pact resistance. 

Plastics  Used  in  the  DC-6 

Following  is  a  list  of  the  22  distinct  chemical  types  of 
plastics,  or  their  variations,  and  the  general  manner  of  their 
use  in  the  DC-6: 

CELLULOSE  NITRATES:  disks  for  fabric   surface  hole  rein- 
forcement ;  dope 
!  CELLULOSE  ACETATES:  drain  boards  for  hydraulic  systems; 

molded  parts 

•CELLULOSE  ACETATE  BUTYRATE:  trim  strips 
Yn.cANiZED  FIBRE:  locking  devices;  electrical  insulation 
PHENOLICS:  molded,  cost  and  laminated  parts 
ALKYDS  :  surface  coatings 

MKI.A MIXES:  electrical  molded  parts;  decorative  laminates 
POLYAMIDES:  washers;  anchor  nuts;  sealants 
THIOKOLS:  fuel  tank  sealants 
SILICONES:  lubricants;  high  temperature  rubber  sealants  and 

insulators 

POLYVINYL  ACETATES  :  paints  and  inks 
POLYVINYL  CHLORIDES:  extrusions;  coatings 
POLYVINYL  CHLORIDE  ACETATES:  extrusions;  coatings 
POLYVINYL  BUTYRAL  :  interlayer  in  safety  glass 
ACRYLICS:  windows;  mirrors;  light  lenses 
POLYETHYLKXES:  electrical  parts 
POLYSTYRENES:  battery  acid  jars  and  separators;  electrical 

molded  parts 

NATURAL  PLASTICS  (SHELLAC)  :  electrical  insulation 
JU-TADIENE-STYRENE  CopOLYMER :  sponge  rubber;  tubing; 

window  frames 

l!i  TADiENE-AcRYLONiTRiLE  COPOLYMER :  fuel  tank  sealant 
I'OI.YCHLORO  BUTADIENE:  hose;  sponge  rubber  carpet  pads 
BrTADiENE-IsoBUTYLENE  COPOLYMER  :  inner  tubes. 

As  pointed  out  by  R.  J.  Considine,  Douglas  plastics  engi- 
neer and  assistant  to  Mason,  e\ery  application  of  plastics  in 
the  cabin  serves  a  definite  functional  purpose. 

With  every  possible  material  to  choose  from,  and  with 
economy  only  a  secondary  objective,  the  record  number  of 
plastics  applications  in  the  DC-6  cabin  evidences  the  fact 
that  these  materials  are  no  longer  classified  as  substitutes, 
but  have  entered  a  phase  where  the  value  of  their  distinctive 
characteristics  is  demonstrated.  END 


"Topping"  Vinyl  Sheet 

(Continued  from  page  18) 


rough  razor-blade  test  made  in  connection  with  this  dis- 
cussion showed  that  topping  can  not  be  scraped  clean  with- 
out taking  some' of  the  vinyl  with  it. 

The  processed  film  as  it  arrives  for  topping  may  have 
any  of  a  number  of  previously  applied  surface  finishes, 
smooth  or  embossed.  Embossed  materials,  which  are  the 
most  frequently  used,  come  in  a  variety  of  treatments : 
ribbed,  striated,  calf,  snakeskin  (including  python  and  rattle- 
snake), "lizigator"  and  others.  The  sheet  may  come  previ- 
ously processed  in  one  color  to  be  topped  with  another,  so 
that  each  surface  presents  a  different  tone — black  on  one 
side  and  red  on  the  other,  for  instance.  An  especially 


THERE  ARE 

TWO  SIDES 

TO  EVERY  STORY 


YOU  may  be  a  plastic  buyer 
who  is  looking  for  the  best  in 
such  stock  items  as  picture  frames, 
door  plates,  drawer  pulls  ot 
cable  clamps 

OR  you  may  be  a  manufacturer 
who  is  looking  for  a  reliable, 
complete  custom-molding  service 

IN  EITHER  CASE,  the  record  of 
Continental  Plastics  Corporation 
insures  the  finest  in  precision 
craftsmanship,  originality  and 
economy. 


Send  or  bring  in  your  sample 
product  or  blue  prints  for  tin 
honest  and  accurate  appraisal. 


CONTINENTAL 

PLASTICS  CORPORATION 


308   WEST   ERIE   STREET 


CHICAGO   10,   ILL. 


NOVEMBER  1946 


PLASTICS 


75 


valuable  feature  of  the  new  process  is  its  ability  to  top  the 
ridge-  of  an  intricately  embossed  material  and  leavt-  the 
depressions  either  devoid  of  topping,  as  in  a  lizigator  effect, 
or  in  pronounced  lighter  shade,  as  in  th.  nake>kin-. 

Variation*  of  light  and  -hade  of  this  character  have  hitherto 
required  long,  careful  and  tedious  hand  manipulation. 

I  he  heart  of  the  automatic  method  of  topping  vinyls  lies 
in  the  print  rollers,  developed  by  Silverman.  and  the  Aridye 
inks.  The  inks  are  mixed  at  the  Silverman  plant.  Color 
matching  to  specifications  is  a  fairly  tricky  procedure  for, 
when  ink  is  applied  to  processed  vinyls,  the  material  appre- 
ciably affects  the  shade.  To  be  certain  of  a  match  and  to 
facilitate  the  matching  process,  the  testing  of  ink  on  vinyl 
is  conducted  under  production  conditions. 

In  the  mechanical  set-up.  Silverman  has  radically  modified 
a  textile  type  of  roller  printer  for  his  purpose.  The  vinyl 
sheet  is  fed  directly  from  feed-roll  to  print  rollers,  from 
which  it  travels  to  an  overhead  heating  chamber,  by  means 
of  which  some  35  yds  of  material,  at  any  given  instant,  are 
being  subjected  to  variations  of  heat  that  drive  off  the 
-olvent  in  the  ink  and  bake  the  pigment  into  the  material. 
The  material  is  then  cooled  to  normal  temperature  to  elimi- 
nate all  tackiness  and  to  bring  the  vinyl  back  to  its  original 
state  liefore  it  is  rewound,  ready  for  shipment.  The  entire 
process  is  continuous. 

Among  the  many  current  applications  of  processed  vinyls 
topped  in  this  fashion  are  upholstery,  for  both  home  and 
automobile  furnishings,  and  handbags.  Luggage  covered 
with  heavy-gauge  vinyl  is  on  the  way,  as  are  vinyl-uppered 
shoes.  The  possibilities  of  using  the  material  as  a  wall 
covering  are  being  explored,  with  the  main  experimentation 
being  conducted  at  present  in  the  development  of  means  of 
adhesion  between  vinyl  and  wall.  END 


Know  Your  Caseins 

i  (  ontinucd  from  page  ' 


during  the  tannery  operations,  all  leather  could  be  tinislux 
with  dyes  and  top  coats  only,  as  in  aniline  leather,  th 
quality. 

However,  the  surfaces  are  seldom  anything  like  perfect 
and  frequently  they  are  further  damaged  in  proc. 
tanning.  In  order  to  cover  up  the  irregularities  as  much 
as  possible  and  to  produce  leather  of  uniform  color  shade 
and  appearance,  all  leather  is  finished  before  it  leaves  the 
tannery.  The  finishing  operation  consists  in  applying  to 
the  grain  surface  of  the  leather  successive  coats  01 "'leather 
finish  until  the  desired  level  of  uniformity  is  attained.  The 
leather  finish  consists  essentially  of  pigment  of  the  desired 
shade,  casein,  and  other  protein  binders  in  alkaline  water 
solution,  with  preservatives  and  leveling-off  agents.  In 
other  words,  a  typical  leather  finish  is  practically  the  same 
as  a  cold  water  paint,  except  that  lime  is  not  always  ,,-cd 
with  the  casein  (formaldehyde  or  some  agent  capable  of 
liberating  formaldehyde  is  usually  present)  and  there  i« 
usually  a  mixture  of  proteins,  rather  than  casein  alone.  The 
mixture  contains  such  proteins  as  blood  albumin.  >i 
buniin.  and  glue.  The  casein  Used  is  an  acid  casein.  N 
tine  self-soured  being  the  most  generally  specified  until 
quite  recently  because  of  the  lack  of  uniformity  in  domestic 
caseins.  The  top  coats,  applied  after  the  pigment  finish  has 
established  level  uniformity,  are  applied  to  produce  luster 
and  consist  in  wax  emulsions  and  egg  albumin.  Th. 
polish  is  brought  out  by  mechanical  friction,  by  brushes,  or 
by  the  glass  glazing  unit. 

Casein  is  present  in  a  number  of  shoe  shop  preparatio 


'US 


THE  GEE-BEE  MFG.  CO. 

PLASTIC   SLITTING,   CUTTING   &   SHEETING    PROBLEMS    SOLVED 


We  slit  all  types  of  plastic  materials  including  cellophane,  acetates,  etc., 

from  1/16  inch  to  75  inches  in  width. 
We  interleave  plastics. 

We  are  equipped  to  slit  up  to  100,000  yds.  per  day. 
Prompt  service. 
Storage  space  available — Equipped  with  railroad  siding. 


WE  ALSO  SHEET  PLASTIC  MATERIALS  FOR  PRESS 
POLISHING  USED  IN  THE  LADIES  HANDBAG  &  SHOE 
TRADES  AND  FOR  ALL  OTHER  PURPOSES. 

Write  to  Us  About  Your  Plastics  Cuffing.  Slitting  and  Sheeting  Problems 

T.I.  Iv.  7-1331 

76  N.  4th  ST.  BROOKLYN   11,  N.  Y. 


76 


I*  I.. \STI1   * 


\"\  I  MUKK    1'Hfi 


used  in  the  manufacture  of  shoes  from  leather.  Many  rubber 
latex  cements  contain  casein  as  an  emulsifier  and  stabilizer 
for  the  rubber  latex  particles.  Bottom  paints,  used  to  cover 
up  blemishes  and  defects  in  the  sole  leather  on  the  shoe 
bottom,  are  frequently  just  cold  water  paints  with  a  casein 
base,  modified  for  the  special  application.  In  many  wax 
emulsions,  casein  is  used  as  the  dispersing  and  stabilizing 
agent.  In  all  these  applications,  acid  caseins  are  used. 

The  largest  industrial  non-food  application  of  casein  is 
in  the  preparation  and  finishing  of  paper.  It  is  probably 
the  best  because  in  this  field  the  fact  that  casein,  a  protein, 
has  rather  poor  comparative  water  resistance  is  of  little 
importance.  The  water  resistance  of  paper  itself  is  not 
good,  nor  is  it  expected  to  be,  and  that  of  the  casein-lime 
mixture  is  as  good  or  better.  The  requirements  are  for  a 
material  with  good  adhesive  properties,  which  casein  cer- 
tainly has.  to  bind  the  fibers  together  to  make  paper  (size) 
or  to  bind  white  pigment  to  paper  surfaces  (coatings). 
Casein  and,  more  recently,  soybean  protein  have  done  very 
well  mixed  with  rosin  soaps  to  bind  the  pulp  fibers  together 
and  thus  to  build  stronger  papers.  By  suitable  modifica- 
tions, paper  for  use  as  towels  can  be  given  increased 
strength  when  wet. 

There  has  been  a  steadily  growing  demand  for  paper 
finished  so  as  to  reproduce  colors  and  half  tones  faithfully 
and  sharply.  This  is  largely  the  result  of  keener  competition 
and  of  sharper  advertising  to  attract  and  hold  the  public 
interest.  Casein  coated  paper  stands  almost  alone  and  su- 
preme as  the  nearly  perfect  paper  for  this  purpose.  The  Na- 
tional Geographic  Society  Magazine  has  been  printed  on 
casein  coated  paper  for  years.  Also  art  prints  and  fre- 
quently maps  where  accuracy  and  sharpness  of  detail  are 
desirable  are  printed  on  casein  coated  paper.  So  satisfac- 
tory has  been  the  application  of  casein  in  this  field  that  the 


t 


PARKWOOD  TRIO! 


PARKWOOD   HI-DEN 


A  quality  compreg  for  industrial  applications.  Park* 
wood  Hi-Den  is  made  from  selected  wood,  impregnated, 
laminated  and  compressed  to  provide  the  characteris- 
tics required  for  your  specific  operation. 

Parkwood  Hi-Den  is  ideal  where  great  tensile  strength 
combined  with  light  weight  are  required.  It  also  pro- 
vides dimensional  stability,  corrosion  and  scratch 
resistance,  dielectric  qualities  and  remarkable  work- 
ability. Use  it  for  precision  jigs,  tools,  forming  blocks 
and  holding  fixtures. 


PARKWOOD   DECORATIVE 


A  beautifully  decorative  laminated  plastic  with  a  wide 
range  of  uses  Available  in  plain  colors  or  in  a  choice  of 
designs.  Widely  used  for  lable  tops  and  work  surfaces 
because  of  its  moisture  and  solvent  resistant  qualities. 


PARKWOOD   ACETATE 


This  highly  specialized  laminated  material  appeals  to 
the  novelty  manufacturer  because  of  its  versatility. 
It  may  be  cut,  stamped  and  worked  easily.  Its  natural 
wood  finishes  have  made  it  a  favorite. 


Consult  our  product  development  department  if  you're  planning  to  produce 
products  in  which  any  Parkwood  material1!  may  be  useful.  There's  no 
obligation,  of  course. 


PARKWOOD  CORPORATION 


K&J 

molds  the  Barrel 
of  this  toy 
Rapid  Fire  Gun 


The  barrel  of  this  improved,  toy  machine  gun,  made  by  the 
Baldwin  Manufacturing  Co.,  is  of  gleaming  Bakelite,  in- 
suring a  most  realistic  and  attractive  appearance, — the 
first  time  that  a  toy  gun   barrel   has  been   made  of 
plastic.  Accurate  K.  &  J.  molds  guarantee  the  proper 
position  of  the  necessary  holes  and  slots,  as  shown  in 
the  illustration. 

The  production  of  such  pieces  by  the  hundreds 
of  thousands  is  a  common  thing  at  K.  &  J., 
where     mold-designing,     mold-making     and 
molding  are  all  done  under  one  roof. 

Why   not  discuss  your  next  molding   job 
with  a  K.  &  J.  representative? 


KUHN&JACOB 

MOLDING    &   TOOL    CO. 

1200   SOUTHARD    STREET,   TRENTON   8,    N.  J. 
CONTACT          TELEPHONE  -  TRENTON  5391 


THE  K  &  J 
REPRESENTATIVE 
NEAREST  YOU 


W  A  K  E  F  I  E  L  D, 


MASS. 


S.  C.  ULLMAN,  55  W.  42ND  ST..  NEW  YORK,  N.  Y. 
TELEPHONE -PENN  3-0346 

WM!  T.  WYLER,  BOX  126.  STRATFDPO,  CONN 
TELEPHONE  -STRATFORD  6-4496 


NOVEMBER  1946 


I'l.ASTMCS 


77 


WE   BUY 


Thermoplastic  Scrap  - 
Rejected  Molded  Pieces 
..Obsolete  Molding 

Powders-and  pay 

highest  prices 


WE   SELL 


Reconditioned  molding 
powdersGUARANTEED 


to  fit  y°ur 


needs 


Your  scrap  ior  you 
WE  SPECIALIZE  in  cus- 
tom grinding,  magnetiz- 
ing, separating  and 

reworking. 


ctuiiosE  icnm  *  HLTSHHRE  .  NETIYI  nETiumm 

A.BAMBERGER 

CORPORATION 

44    HIWIS    STKIIT.     •ROOKLYN     II,    N.    '.. 
fHONl  rVMGUMN  /  J8«7  •  CAItt  CMfMMOD  MOOKtrN 


amount  used  has  varied  from  U-tween  half  and  three  quar- 
ters of  all  domestic  casein  in  indu.strial  non-food  use.-.  For- 
merly  the  Argentine  self-soured  casein  wa-  -|>ecitied  by  the 
paper  trade,  because  of  lack  of  uniformity  in  the  domestic 
caseins,  but  today  the  domestic  acid  caseins  are  being  u-ed 
very  extensively  and  generally  quite  satisfactorily.  Soybean 
and  other  proteins  have  been  unable  to  replace  casein  to  any 
extent  as  a  paper  coating  binder  because  of  their  darker 
color.  Improvement  of  this  usually  results  in  loss  of  ad- 
hesive strength,  so  casein  remain.-  the  best  protein  for  both 
color  and  stiength.  Starch  has  good  color  but  lack-  the 
water  resistance  of  casein,  so  it  does  not  appear  a-  a  -crious 
competitor. 

Conclusion 

Casein,  the  protein  produced  from  cows'  milk,  pro-em-  a 
very  good  picture  of  how  materials  find  their  industrial 
levels,  in  the  long  run,  as  the  result  of  performance  ami  not 
of  bally  hoo  and  wishful  thinking.  Casein,  a  protein,  has 
poor  water  resistance  as  compared  with  synthetic  re-ins. 
cellulose  derivatives,  and  other  plastics  materials.  Its  field 
of  usefulness  as  a  plastics  or  as  a  surface  coating  i-  re- 
stricted to  those  applications  where  water  resistance  is  com- 
paratively unimportant.  And  in  this  field,  paper  coatings 
and  leather  finishes,  it  dominates.  As  the  only  indu-trial 
application  for  rennet  casein,  plastics  buttons  have  been  -uc- 
ee— fully  developed.  The  water  resistance  of  the  material  is 
adequate  for  ordinary  use,  and  its  beauty  and  possible  dec- 
orative effects  are  unsurpassed.  But  to  remain  as  a  • 
in  the  plastics  picture,  means  must  be  found  to  mold  ca-ein 
comparable  with  other  plastics  and,  at  the  same  time,  im- 
prove its  water  resistance,  with  attendant  improvement  in 
stability  and  permanence.  i  M> 


Clare-Proof  Surfaces 

(Continued  from  patie  -- I 


CIUIIISC  U(ll      IIITIITC 


MlHIRYl  ItSIHS.  tfC. 


as  high  as  300°  F.  The  higher  heat,  when  feasible,  is  rec- 
ommended to  drive  the  pla-tics  material  into  the  wea\.  , if 
the  cloth.  But  trial  runs  to  determine  the  heat  at  which  the 
fabrics'  color  will  deteriorate  should  be  undertaken. 

In  another  preliminary  test  the  fabric  is  exposed  to  the 
sun  for  at  least  three  consecutive  days.  Practice  has  shown 
that  sun-fast  colors  usually  hold  under  the  higher  laminating} 
temperature. 

Colorful  textiles  with  attractive  designs  are  also  Ix-ing 
used  in  increasing  extent  as  the  inner  ply  for  cove- 
advertising  brochures  and  books  of  similar  nature.    Textiles, 
of  cour-e.  have  been  utilized  in  this  way  for  some  time  when 
laminating  coasters  and  runner-. 

Another  application  of  cloth  as  the  inner  ply  was  in  pn 
duction  of  company  arm  band-.     Silk  -crccn-printed  cotton 
yardage,  laminated  between  cellulose  acetate  sheet-,  is  rapid- 
ly replacing  the  old  style  embroidered  chevron.     The  new 
product   i-  smarter  looking,  has  high  optical   pro|x-rtic-.  is 
virtually  tear  proof,  is  cleanable  with  -oap  ami  wat<-< 
resists  moi-ture  and  grease  absorption. 

(•animations  of  colored  acetate  ply  In-twoon  clear   -beets 
of  the  same  material  have  had  numerous  application-.    Pur- 
ing  the  war  waterproof  color  filters  wore  fabricated  by  th 
method  for  Navy  landing  signal-.     Made  in  smaller  ditm-n- 
-loii-  and  gicater  color  range,  sandwiched  tillers  wei. 
by  visual  education  classes  to  study  chromatic  blend-  formed!] 
by  light  transmission. 

Anothci  '••!   wa-  in  clear  cellulose  acetate  waffl 

protectors  for  placement  behind  electric  -witch  pi 
punched  with  a  die  to  cone-pond  with  th. 
plate'-  -crew   hole-  and  control  handle  o|K-ning. 

I 'tin-ess  printing  on  opaque  or  Iran-parent  cellulose  ni- 
ii. id-  -audwiched  In-twcen  laminated  i'fU»f>liaH?  ha-  bad 


NOVKMHKR   1«M6 


wide  utilization  in  bookmarks  and  business  cards.  Trans- 
parent overlays  of  this  type  for  municipal  maps  aid  police 
departments  in  keeping  ever-changing  records  concerning 
whereabouts  of  radio  cars  and  patrolmen. 

In  classrooms  these  transparent  overlays  operate  on  the 
principle  of  a  slide  rule  for  studies  of  variable  graphs  and  to 
obtain  three-dimensional  effects. 

New  channels  are  constantly  opening  for  the  laminating 
field.  Recently,  the  sandwiching  of  Kodachrome  film  be- 
tween cellulose  acetate  sheets  was  undertaken.  An  outer 
ply  of  .005"  furnished  flexural  strength  and  adequate  protec- 
tion for  frequent  use  of  the  film.  A  heavier  ply  of  .030" 
provided  rigidity  comparable  to  that  of  a  glass  lantern  slide. 

Another  new  operation  was  the  laminating  of  gold-plated 
metal  membership  cards  issued  by  a  club.  Sheets  of  .015" 
:ellulose  acetate  w-ere  used  on  both  sides  of  the  metal.  As 
metal  is  not  damaged  by  high  laminating  temperatures,  con- 
siderable latitude  in  temperature  was  permitted,  which 
speeded  the  process.  END 


Building  Better  "Shakers" 

(Continued  from  foge  33) 


1 

j 


ire  also  available.  The  dispensers  in  their  various  colors 
ind  combinations  are  available,  whether  in  plastics  or  plas- 
ics-lined  metal,  in  either  classic,  streamlined,  or  modern- 
stic  designs.  Also  available  are  dispensers  engraved  with 
'arious  insignia  and  monograms  as  well  as  decorative  decal- 
:omanias  furnished  by  the  Meyercord  Company,  Chicago. 

Although  the  new  dispensers  are  priced  slightly  higher 
han  conventional  salt  and  pepper  shakers  and  previous 
ilastics  makes  of  the  controlled  plunger  type,  the  public,  ac- 
ording  to  officials  of  the  company,  not  only  approves  and 
s  willing  to  pay  for  the  added  quality,  but  also  has  not  been 
Isillusioned  by  misuses  of  plastics  with  which  they  are 
amiliar.  In  making  the  new  thermosetting  moisture-proof 
fcpensers,  the  policy  of  sacrificing  production  speeds  to 
uality  proves,  according  to  H.  H.  Bashore,  general  man- 
ger, to  have  been  wisely  adopted. 

The  standard-sized  table  sets  of  salt  and  pepper  dispens- 
rs  constitute  the  first  items  of  a  series  of  domestic  dispens- 
rs  planned  by  the  Sonette  Plastics  Company.  Models 
ave  been  made  of  large  dispensers  of  salt  and  pepper  for 
•eneral  kitchen  use,  of  small  individual  dispenser  sets  for 
:sc  by  airlines  and  steamship  lines,  and  of  large  dispensers 
ar  the  dispensing  of  powders,  liquids,  and  other  cosmetics 
ir  dressing  table  use.  Additional  products  are  in  earlier 
levelopmental  stages.  END 


PRECISION  RAM  TYPE  NO.  7-B 

VERTICAL  UNIVERSAL 

MILLING  MACHINE 


•  Flexible 

•  Sturdy 

•  Universal 


Easy  to  operate 
One  set  up 
All  angles 
quickly  obtained 


•  Four  Sizes 

•  Four  Types 


•   Adaptable  to  all 
Milling  Machines 


for  further  information 
write  Dept.  P 


Button  is  cemented  to  stem  after  springs  are  inserted 


H.  LEACH    MACHINERY    CO. 

387    CHARLES    ST.  PROVIDENCE    4,    R.    I. 

AGENTS      IN      All      PRINCIPAL      CITIES 


NOVEMBER  1946 


PLASTICS 


79 


INDUSTRY  HIGHLIGHTS 


Plastics  material  manufacturers  arc  continuing  their  po>t- 
war  expansion  program,  which  is  expected  to  total  at  least 
$125,000,000  by  1948,  despite  the  program's  being  retarded  by 
strikes  and  shortages  of  basic  chemical  elements,  according  to 
Frank  K.  Carman,  general  manager.  Plastics  Materials  Manu- 
facturers Association,  in  a  talk  delivered  on  October  18  at  a 
meeting  of  the  New  England  section.  Society  of  the  Plastics 
Industry,  in  Manchester.  N't. 

Substantial  increases  in  production  of  most  plastics  supplies 
were  noted  by  Mr.  Carman,  including  that  of  thermoplastic 
molding  powders  (exclusive  of  vinyls)  which  is  now  more 
than  one  and  one-half  times  that  of  1945;  and  increase  of  pro- 
duction of  thermosetting  molding  powders  which,  in  August 
of  this  year,  had  exceeded  1945  production  figures  by  40%.  The 
plastics  molding  industry,  he  said,  considered  as  a  unit  appears  to 
be  using  all  types  of  materials  at  double  the  rate  attained  in  1941, 
and  4S'i  greater  than  the  rate  of  1945.  On  the  basis  of  r-ti- 
mates  from  PMMA  members,  plans  for  additional  facilities  are 
now  under  way  to  provide  total  molding  materials  in  quantities 
approximately  two  and  one-half  times  the  amount  available 
in  1945. 

He  stated,  however,  that  present  or  pending  shortages  of 
phenol,  cresols  and  crcsylic  acids,  phthalic  anhydride,  urea  and 
formaldehyde,  glycerine,  plasticizers,  benzol  and  alcohol,  cot- 
ton ItntiTs.  pigments  and  lubricants,  are  part  of  the  cumulative 
effect  of  the  coal  and  steel  strikes  and  of  recent  strikes  in  the 
l.asic  chemical  industries,  and  with  regard  to  plasticizers.  In- 
warned  that  "Some  industry  members  predict  that  supplies  will 
be  even  more  critical  in  1947,  when  increased  resin  production 


A  new  silicone  paint  which,  it  is  claimed,  will  afford  life- 
time finish  for  automobiles,  refrigerators,  electric  ranges,  and 
hospital  equipment,  is  being  developed  at  the  General  Electric 
chemical  department  in  Schencctady.  according  to  recent  an- 
nouncement. 

Tests  of  the  paint,  which  is  still  in  the  developmental  stage  at 
the  General  Electric  plant,  are  said  to  have  indicated  that  the 
silicone  product  is  highly  resistant  to  severe  weather  conditions, 
chemicals,  and  heat,  and  that  it  possesses  various  other  desirable 
characteristics  such  as  resistance  to  discoloration  frequently 
i  aiiscd  by  hot  grease  or  oils,  fruit  juices,  iodine  and  other  chem- 
icals. 

Other  silicone  products  in  process  of  development  at  the  G.E 
chemical  department,  according  to  company  officials,  include  sili- 
cone resins.  oi|>,  greases,  and  rubber.  Although  the  production 
of  silicones  by  the  company  at  present  is  on  a  pilot  plant  scale, 
operation  of  General  Electric'-,  new  factory,  now  under  con- 
struction at  NVaterford.  \.  Y..  for  the  manufacture  of  silicones, 
will,  according  to  recent  announcement.  Ix-gin  some  time  after 
the  first  of  the  coming  year. 


the  first  IliKir  is  to  he  used  for  storage  of  molding  powder,  an 
plans  call  for  installation  of  a  two-way  conveyor  system  K-twee 
the  first  floor,  and  the  third  floor  of  the  company's  present  plan 


The  sixth  chapter  of  the  technical  handbook  being  developed 
by  the  S.,.i<tv  of  the  I'lastics  Industry  is  to  be  released  early  in 

•  Imi:   to  announcement   from  the  Society. 

Titled   "Design  of   Molded  Articles,"  this  chapter   is  divided 

into  v,-.  Hon.  following  basic  principles  of  the  subject  with  which 

;s.   "offering   a  complete   presentation   of   design   problems 

and  their  solution  in  the  average  plant."     It  was  prepared  by  a 

committee  of  twelve  authorities  in  pi. 


A  new  company,   Vermont  I'l.Mi. •«.   Inc..  has  been   formed 

by   A.    D.    Hayes   and    N'ewell  Curtis,   at    Montpelicr.    N't.    to 

produce   plastic*   clothespins    in  various   i,,l,,rs.    for   distribution 

through   department   and  chain  stores   in   the  area  east   of   the 

'!'!•' 

A  year'*  lease,  with  option  to  purchase,  has  been  taken  by 
Worcester   Moulded   Plastics  Co.  N\ 

••rick  building,  according  to  announcement.     The  building 
will  provide  thr  company  with   |r,.imi  .idditi-.tul  si|   it  of 


Formation  of  the  Taco  NVest  Corp.,  Chicago,  has  been  ai 
nounced.  with  Theodore  A.  Cohen  as  president,  and  Richard  Y 
NN'est.  secretary-treasurer.  The  new  company,  which  is  locate 
at  2620  South  Park  Ave.,  plans  manufacture  and  marketing  < 
automatic  electronic  control  devices  in  the  fields  of  combustio 
control,  gas  analysis,  pyrometry,  process  control  and  allied  aj 
paratus. 


Several  types  of  1'nlystnl.  a  self-hardening  glue,  have  Re- 
produced on  a  large  scale  in  an  I.  G.  Farbcn  plant,  in  German) 
according  to  report  from  the  U.  S.  Department  of  Commero 
Wood  joints  made  with  Polystol  are  described  as  having  U-e 
found  strong  enough  to  meet  requirements  for  the  German  ait 
craft,  automobile,  and  shipbuilding  industries,  and.  according  t 
the  manufacturer,  the  glue  is  not  brittle,  and  is  resistant 
or  to  boiling  water. 

The  Polystals  are  made  from  Desmodurs  and  Desmopkit 
which  are  also  produced  by  I.  G.  Farben,  the  Desmodurs  bea 
polyfunctional  isocyanates,  and  the  Desmophens,  polyesters  pre 
pared  by  esterification  of  adipic  and  phthalic  acid  with  trihydrox 
alcohols  such  as  glycerins,  or  with  dihydroxy  alcohols.  The* 
preparations,  when  mixed  with  each  other,  form  solid  compound 
of  high  molecular  weight. 

Another  I.  G.  Farben  product  is  an  expanded  plastic-  calle 
Mfillofrcn,  based  on  the  reaction  of  a  Desmodur  with 
iiii>f>hen  containing  some  carboxyl  groups.    According  to  dc-ciip 
tion.  liberation  of  carbon  dioxide  results  in  expansion  of  tl 
to  form  a  material  with  a  cellular  structure.     The  material  ha 
been  found  to  have  limited  uses  for  sound  insulation  and  for  hea 
insulation  at  low  temperatures. 


Development  of  a  new   plastics   material,  to  be  known  a 
Injropakc.  has  been  announced  by  Chas.  Fischer  Co,  I'.r.-.klyr 
X.  Y.     Similar  in  appearance  to  other  plastics,  and  avail 
several  colors,  this  new  material,  according  to  its  manufactur 
<TS.  will  transmit  visible  light  only  and  at  the  same  time  selec- 
tively absorb  light  waves  known   to  be  harmful  in  overdoses- 
sin  h  as  the  infrared  and  ultraviolet  rays.     A  variety  of  applica 
tions  foreseen  by  the  company  for  Injrupake  include  spoi  • 
gles.  automobile  windshields,  sun  visors,  industrial  goggK-  .nx 
windows,   packaging    foil,   insulating   material   in   buildii 
others. 


Synthetic  enamels  and  clear  finishes,  said  to  hake  in  a  matW 
of  seconds,  have  been  developed  by  M.ias  \  \\al.lstein  Cfl 
Newark,  X.  J.  Called  l:lashdur.  these  new  products  are  (H 
signed  to  aid  in  reducing  production  schedules  to  a  minimum  fa 
manufacturers  of  compacts,  lipstick  cases,  lighters,  and  <>th« 
items  where  a  hard,  tough  and  fast-baking  finish  of  this  type] 
desired. 


Establishment  oi  a  new  sales  office  at  140  Federal  St.. 
ton.  has  IH.-CII   rc|>ortcd  by  The   H.   F.   Goodrich  Chemical 
NY.  I).  I.ahcy  and  J.  J.   Hreen.  who  formerly  hcadquari- 
New    York  City,  will  IK-  sales  representatives  for  the  comp 
Geon  thermoplastics  in   Itoston  and  the  Xew   England  territor 


Report  of  purchase  from  the  NN'AA.  by  Package  Machined 

I  the  plant  at  Fast   Long  meadow.  Mass  .  occupied  !• 
.\  \Vhitne>  Aircraft  during  the  war.  has  been  received.    Acqud 
lion  of  the  plant,  it  is  estimated,  will  triple  the  company's  maBJ 
1:1.11  luring  space  and  permit  considerably  increased  i  inploymcfl 
Plans  of  Package  Machinery  Co..  according  to  re|mrt,  arc  M 
hdation  of  its  operations  at  the  new   plant,  eliminating  thl 
subcontracting  of  a  large  amount  of  work,  which  had  t- 
been  made  necessary   by   lack   of   sj>acc  in  the  company's   pre- 
viously-occupied i|tiarlcr« 


80 


ri. 


NOVEMBER   194 


Creation  of  a  new  plastics  production  division  in  the  B.  F. 
Goodrich  Co.,  with  Bert  S.  Taylor  as  factory  manager,  has 
been  announced.  Mr.  Taylor  has  been  general  superintendent 
of  Goodrich's  processing  division  for  more  than  eight  years,  with 
direction  of  processing  of  plastics  in  the  company's  Akron  plants  ; 
Robert  H.  Wattleworth  has  been  named  to  succeed  him  in 
that  position.  In  his  new  post,  Mr.  Taylor  will  have  charge  of 
the  new  plastics  processing  plant  being  built  by  Goodrich  near 
Marietta,  O. 

*  *     * 

Charles  A.  Jeanson,  III,  has  been  appointed  western  sales 
manager  of  the  Lumite  Division,  Chicopee  Mfg.  Corp. 

*  *     * 

Dr.  F.  L.  Minnear  has  assumed  charge  of  development  and 
research  in  the  field  of  plastics  for  Shellmar  Products  Corp.,  and 
will  headquarter  at  the  company's  plant  in  Mt.  Vernon,  Ohio. 


B.  S.  Taylor 


C.  A.  Jeanson,  III 


F.  L.  Minnear 


Homer  W.  Derby  has  been  appointed  works  accountant  of 
General  Electric  Co.'s  new  laminated  plastics  plant  at  Coshocton, 
0.,  having  previously  served  in  a  similar  capacity  at  the  com- 
pany's plastics  factory  at  Lynn,  Mass.,  which  is  being  transferred 
to  Coshocton. 

*  *     * 

Mogens  H.  Bendixsen,  who  has  been  associated  with  the 
export  division,  Owens-Illinois  Glass  Co.,  for  the  past  six  years, 
has  resigned  to  become  vice  president  of  Melvin  Pine  &  Co.,  New 
York  exporting  firm.  He  will  have  charge  of  the  company's 
Toledo  office,  which  acts  as  export  managers  for  manufacturers 
of  industrial  and  building  specialties,  machinery  and  processing 
equipment. 

*  *     * 

Personnel  appointments  recently  announced  by  E.  A.  Clare, 
president  of  Athol  Mfg.  Co.,  Athol,  Mass.,  are  those  of  Fred 
E.  Wilcock  to  the  post  of  assistant  treasurer  of  the  company, 
and  Robert  M.  Tyler  to  that  of  assistant  sales  manager. 

*  *     * 

James  D.  Greensward  has  been  named  assistant  to  William 
C.  Johnson,  vice  president  of  the  general  machinery  division  of 
Allis-Chalmers  Mfg.  Co.,  Milwaukee. 

Other  recent  personnel  appointments  within  the  company,  in- 
clude those  of  James  R.  Reed  to  manager  of  the  commercial 
research  department ;  Jerome  F.  Fitzsimmons  to  supervisor 
in  charge  of  research ;  and  Anson  J.  Bennett,  Jr.,  who  has 
been  made  supervisor  in  charge  of  sales  analysis. 

*  *     * 

Joseph  H.  Fulmer,  formerly  connected  with  the  Ethyl  Cor- 
poration and  Sharpies  Chemicals,  has  joined  the  engineering  de- 
partment of  Pennsylvania  Salt  Mfg.  Co. 

Louis  M.  Kuilema,  formerly  district  sales  manager  at  the 
company's  Cincinnati  office,  has  been  placed  in  charge  of  the 
\VJMimsin  territory  as  district  sales  manager;  Charles  W. 
Dermitt  has  succeeded  Mr.  Kuilema  in  Cincinnati. 

*  *     * 

Among  personnel  appointments  recently  announced  by  Koppers 
Co.  Inc.,  Pittsburgh,  are  the  following:  Vice  president  Dan  M. 
Rugg  to  general  manager  of  the  company's  new  chemical  di- 


eve/up 

TO  YOUR  SPECIFICATIONS 

For  over  forty  years  we  have  been  leaders  in  the  design 
and  manufacture  of  component  parts  for  leading 
Refrigerator,  Stove,  Furniture,  Appliance  and  Cabinet 
industries.  We  specialize  in  custom  molding  by  the 
injection,  compression  or  transfer  method  in  any  ther- 
mosetting  or  thermoplastic  material.  A  complete  ser- 
vice from  one  source  to  serve  your  needs  —  at  no 
extra  cost. 


RESEARCH  — 

Highly  experienc- 
ed research  engi- 
neers to  deter- 
mine the  material  best  suited 
for  your  needs  as  to  strength, 
utility  and  beauty. 


ENGINEERING— 

Here  is  where  the 
correct  tools,  pre- 
cision dies  and 
molds  are  developed  to  pro- 
duce the  best  job,  efficiently 
and  economically. 


MOLDING   —  A 

complete  depart- 
ment equipped 
with  the  latest 
and  most  modern  presses  and 
molding  equipment  —  for 
Injection,  Compression  or 
Transfer  molding. 


DESIGN  —  A  thor- 
ough study  is  made 
as  to  the  utility, 
shape  and  color  of 
the  plastic  part  that  will  best 
harmonize  with  the  style  and 
design  of  your  product. 


TOOL  AND  MOLD 
MAKING  —  This 
department,  manned 
by  expert  crafts- 
men, makes  the  necessary 
tools  and  molds  to  produce 
the  finished  product. 


INSPECTION 
AND  SHIPPING 

Each  individual 
piece  is  carefully 
inspected  for  uniformity,  col- 
or and  finish.  All  parts  are 
carefully  wrapped  and  packed 
for  utmost  protection. 


//  you  are  planning  the  use  of  plastic  parts  in  your 
products,  it  will  be  advantageous  for  you  to  investi- 
gate our  complete  service.  Write  or  phone  us  about 
your  needs. 


NATIONAL   LOCK 
COMPANY 

Plastics   Division 

ROCKFORD,    ILLINOIS 


NOVEMBER  1946 


PLASTICS 


81 


COMPLETE 
MOLDS 


lor  injection 
and  compression 
molding 


SERVING    THE     PLASTICS     INDUSTRY 

We  ipecioliie  exclutively  in  moldi.  hobi.  bobbed  coviliei, 
and  ileel  ilompt  S«nd  u>  you'  moil  .niricoie  dtngni.  your 
iough«tf  mold  making  problem.  Your  d«iign  or  blueprint 
will  be  reproduced  to  the  flneil  prtcition  detail* 


TAPS    •    MOSS    •    DIES    •    STAMPS  fO»   PIASTICS 

SOSSNER 

141     GRAND     STRIET.     NIW     YORK     13 


vision  ;  vice  president  J.  N.  Forker  to  general  manager  of  the 
now  tar  products  division;  J.  C.  Macon,  Jr.,  general  sales  man- 
ager of  the  tar  sales  department,  handling  sales  of  tar  product-  and 
coated  products  of  the  company.  T.  C.  Keeling  has  been  named 
sales  manager  of  the  chemical  division. 

Vice  president  W.  Reed  Morris  has  become  general  m:, 
of  the  company's  new  gas  and  coke  division  ;  vice  president  J.  F. 
Byrne  has  received  special  assignments  for  the  engineering  and 
construction  division;  \ice  president  M.  T.  Herreid  has  IK 
made  manager  of  Koppers'  plants  at  Granite  City,  111.,  anil  St. 
Paul,  Minn.  George  M.  Walker  has  become  manager  of  the 
control  section. 


George    R.    Vila,    formerly    assistant    development    ma 
Naugatuck  Chemical  Division  of  United  States  Rubber  Co..  has 
become  sales  manager  for  the  company's  plastics  products,  rub- 
ber dispersions,  latex,  and  Loiol.    He  will  make  his  headquarters 
at  the  chemical  division's  plant  in  Xaugatuck,  Conn. 


D.  M.  Rugg 


J.  N.  Forker 


G.  R.  Vila 


Reginald  Rockwell,  who  was  assistant  general  mana. 
the  paper  makers  chemical  department  of  Hercules  Powder  Co, 
has  been  appointed  general  manager  of  that  department.  su< 
ing  Ralph  B.   McKinney,  who  died  on  September  21. 
»     *     * 

Thomas  B.  Tomkinson,  controller  of  The  B.  F.  Goodrich 
Co.,  since  1927  and  one  of  its  directors  from  1928  to  194*1.  has 
announced  his  intention  of  retiring  on  December  31,  194<>. 

*  *     * 

Dr.   E.  J.  Jacob  has   recently  joined  the  research   staff  of 
Plastics  Guild  Corp..  New    York,  to  assist  in  the  compam 
pansion  program,  according  to  announcement   made  by   ( >    <  >. 
Brant,  president. 

*  *     * 

S.  Leon  Kaye,  formerly  associated  with  Consolidated  Molded 

I    Products  Corp.  and   Universal   Plastics  Corp.,  has  formed  the 

Kaye  Plastics  Corp.,  at  Stclton,  N.  J. 

*  *    * 

\nnounccmcnt  has  been  received  from  E.  I.  du  Pont 
de  Nemours  &  Co.  of  the  retirement  of  Roberts  W.  Brakaw, 
•ary  and  a  director  of  The  Celastic  Corp.,  a  partly-owned 
Du  Pont  -iihsidiary.  He  is  being  succeeded  by  Benedict  Van 
Voorhis,  manager  of  procurement  for  the  Du  Pont  plastics  dej 
partmcnt. 

Walter  A.  Miller,  who  was  formerly  sales  manager  of  the 
product-  division.  Du   Pont  plastics  department,  has  been  • 
dir. .  tor  of  sales  of  that  division. 

*  •     * 

The   II     K     Porter   Co..   Inc..    Pitt-burgh,  ha-  announced   that 
C.    R.    Dobson    has    Ix-en    elected    vice    pre-ident    ill    chai 
operation   for  the   company. 

Clyde  O.  DeLong  ha-  IK-CII  named  merchandise  mana. 
the  industrial  products  sales  divi-ion  of  The  H.  F.  (inudrich  CoJ 
succeeding  Fred  A.  Lang,  recently  apixiinted  general  managed 
of  the  company'-  newly  created  shoe  products  -ale-  division. 

*  •     e 

Recently  announced  l>y  I'clanese  Corp.  of  America  i-  the  a 
\aiircmcnt  of  John  J.  Keville,  Jr.,  to  the  po-t  of  dire 
product  application  of  the  company's  plastics  division.     Frank 
Sanford  lias  been  appointed  to  raoond  Mr    Keville  a-  a- 
dirertor  of  -ale-  of  the  plastic-  ilivi-ion'-  molding  n 
IMttmrnl 


82 


NOVKMHKR    1!Mfi| 


Autumn  Meeting,  SPI  Midwest  Chapter 

November  7  and  8  have  been  announced  as  the  dates  for  the 
lutumn  meeting  of  the  midwest  chapter  of  the  Society  of-  the 
Plastics  Industry,  to  be  held  at  French  Lick,  Indiana. 

Scheduled  for  presentation  in  morning  technical  sessions  of 
he  meeting  are  the  following  technical  papers :  "Teflon,"  pre- 
;ented  by  E.  B.  Yelton,  E.  I.  du  Pont  de  Nemours  &  Co.,  Inc. 
(plastics,  July  1946)  ;  "Plastics  Materials  Outlook,"  by  Frank 
barman,  Plastics  Materials  Manufacturers  Ass'n. ;  "Roll  Leaf 
stamping  on  Plastics,"  by  C.  A.  Lydecker,  Peerless  Roll  Leaf 
~o. ;  and  "Printing  on  Vinyl  Film,"  by  Chester  M.  Robbins, 
Vridye  Corp. 

Members  of  the  meeting  committee  are :  Norman  Anderson, 
jeneral  Molded  Products,  Inc. ;  Charles  F.  Elmes,  Elmes  Engi- 
leering  Works ;  Marvin  M.  Lane,  Croname,  Inc. ;  and  W.  K. 
Voodruff,  Celanese  Plastics  Corp. 


few  York  SPE  Section 

The  first  regular  meeting  of  the  newly  formed  New  York 
ection  of  the  Society  of  Plastics  Engineers  was  held  at  the 
iotel  Sheraton  on  September  18,  presided  over  by  Robert  Brin- 
:ema,  president.  Featured  speaker  was  Clinton  Blount,  vice 
iresident  of  Bakelite  Corp.,  who  put  the  shortage  of  plastics  in 
ts  proper  perspective  by  citing  the  shortages  in  other  materials. 

Mr.  Blount  displayed  some  items  produced  by  low  pressure 
nolding,  to  illustrate  how  new  developments  were  constantly 
xpanding  in  plastics  usages.  He  was  introduced  by  William  T. 
,'ruse.  executive  vice  president  of  the  SPI. 


1STM  Announces  Annual  Meetings 

Dates  for  the  1947  national  meetings  of  the  American  Society 
or  Testing  Materials  have  been  announced  by  that  organization. 

The  1947  spring  meeting  and  committee  dates  have  been  sched- 
iled  for  February  24  to  28,  at  the  Benjamin  Franklin  Hotel, 
'hiladelphia.  Technical  feature  of  this  meeting  is  to  be  a  sym- 
'Osium  on  testing  and  evaluation  of  paints  and  paint  materials, 
aider  the  joint  sponsorship  of  the  society's  Committee  D-l  on 
aint,  varnish,  lacquer  and  related  products,  and  the  ASTM 
'hiladelphia  district.  The  society  hopes  to  have  the  dedication 
xerdses  and  open  house  at  its  new  headquarters  building  in 
'hiladelphia  during  that  week. 

June  16  to  20  have  been  selected  as  dates  for  the  organization's 
ftieth  annual  meeting,  at  the  Chalfonte-Haddon  Hall  hotel, 
Atlantic  City. 


iPE  Changes  Exposition  Dates 

Announcement  has  been  made  by  the  Society  of  Plastics 
Engineers  that  the  dates  for  its  Third  Annual  Exposition  have 
een  changed  to  January  25  through  January  31,  1947.  Technical 
leeting  dates  are  January  27  to  31,  at  the  Congress  Hotel. 


Vestern  New  England  SPE  Officers 

Mario  Petretti.  general  manager  of  the  plastics  division,  Noma 
Electric  Co.,  Holyoke,  Mass.,  has  been  elected  president  of  the 
Bcently-organized  Western  New  England  section  of  the  Society 
f  Plastics  Engineers.  Other  officers  are:  Frank  J.  Donahue, 
lonsanto  Chemical  Co.,  Indian  Orchard,  Mass.,  vice  president ; 
leorge  W.  Carlson,  Arrow,  Hart  &  Hageman  Co.,  Hartford, 
'onn.,  treasurer:  and  J.  T.  F.  Bitter,  Parker  Stamp  Works, 
lolyoke,  secretary. 

The  section  includes  Vermont,  New  Hampshire,  western 
lassaclmsetts,  and  northern  Connecticut. 


RES f  ARCH  tfatfrtt  it 
t*  you*  need  EXACTLY 


FILFLOC — Pure  cotton  flock  of    FABRIFIL — Uniformly  prepared 
surpassing  cleanliness  and   uni-    macerated  cotton  fabric  for  ex- 
formity.  tra  strength. 

Request     Samples     and    Prices 
of  these  DEPENDABLE  Fillers 


RAYON  PROCESSING  CO. 

45    TREMONT    ST.,  CENTRAL    FALLS,    RHODE     ISLAND 


of  K.I. 

INC. 


Gotta*  4ilU*A  (o*  PtatiicA 


JOVEMBER  1946 


PLASTICS 


83 


/Ji  ZaAif,  Al  1 

COLOR 
YOUR   PLASTICS! 

REZ-N-DYE* 

(COLO  DIP  DYE) 

NO  HEAT!— NO  MIXING! 

Fast  Colors  all  plastics  in  a  matter  ol  seconds  or  min- 
utes depending  on  depth  of  shade  desired.  Simply 
immerse  in  dye,  rinse  in  water,  wipe  dry.  Polishing 
does  not  affect  color. 

21  Different  Colors  s*5  Gallon  F.  0.  B.  Factory 

Mottling  Compound  for  TORTOISE  SHELL  Efftct  53.00  Qt. 

SCHWARTZ  CHEMICAL  CO. 


326-328  West  70th  Street. 


•REZ-N-KLEEN" 

REZN    GLUE- 


New  York  23,  N.  Y. 
•Trad.  Mark 


INSTANTLY  removes  all  foreign  sub- 
stances from  Lucile  and  Plexiglas. 

New!  Improved!  Water  White.  Per- 
fect for  cementing  most  everything 
to  plastics. 


WE'LL  MAKE  IT 

Whenever  the  problem  of  selecting  a  plastic 
molder  arises  consult  KIRK  first.  The  variety  of 
products  we've  produced  is  your  assurance  that 
you'll  be  right  with  KIRK. 

Don't  fuss  with  problems  in  plastics  .  .  .  refer 
them  to  KIRK.  The  service  is  camp/ere  and 
dependable. 

••tall  Slere  Buyer*  I  Aik  about  fail- 
•effing,  profitable  proowcti  by  KIRK. 

m  F.  J.  KIRK  MOLDING  CO. 

I    I  I  I    CUNTON,        MASSACHUSETTS 


"Midget"  pump  develops  pressures  up  to  5000  psi  and  40  hp 


Small  Pump 
Gives  Biff  Output 


IN'  KKKI'IN't'i  with  the  mcxlern  machine  designer'-  objec- 
tive to  produce  more  work  from  a  minimum  area  of  floci 
space  and  a  minimum  number  of  pounds  of  metal.  Super- 
draulic  Corporation,  Dearborn,  Mich.,  has  produced  a 
"midget"  pump  that  develops  pressures  up  to  5000  p-i  and  40 
hp,  although  it  is  only  9"  in  diam. 

Ideally  suited  in  application  to  plastics  molding  machin- 
ery, the  pump  is  available  in  two  types — one  for  constant 
delivery,  another  for  controlled  variable  delivery  \\ith  lin- 
ger volume  control.  If  desired  any  one  of  a  number  of 
other  controls  are  available,  including  automatic  pressure 
compensator. 

Briefly,  the  pump,  a  radial-type  plunger  pump,  is  arrang 
-o  that  centrifugal  forces  at  speeds  of  more  than  HHI  rpin 
maintain  the  plunger  roller-  in  contact  with  an  elliptical  ren 
action  ring.  Plungers  are  fitted  to  cylinders  in  a  rotor  in 
one  or  more  banks  of  11  plungers  per  bank. 

The  rotor  turns  on  a  fixed  central  pintle  which  ha-  -un- 
able ducts  and  port-  for  directing  the  oil  intake  into  tho-e 
cylinder-  pa-sing  through  two  opposite  <|iiadrants  of  the 
stationary  rings  (Which  can  be  compared  with  cam  ring-) 
and  al-o  for  delivering  the  oil  out  of  the  cylinder-  pa--mg 
through  tbe  op]x>-ing  i|uadrants. 

Kach   plunger  makes  two  inlet  and  two  delivery   si 
|H-r  revolution,  operating  within  a  maximum  range  of  tra\el 
of  ')   lo".     Plungers  are  universally  attached  to  an  eijiiali/- 
ing  axle,  journalizing  two  rollers  approximately  1  V  diam. 
which  roll  on  the  elliptical  ring-. 

Tin-  coii-triiction  provides  ample  In-aring  area-  for  the 
plunger  load  conipi incut-  exerted  radially  and  rotath 
the  axle-K-aring  surfaces-  and  in-ure-  zero  -ide-loadini;  .<f 
the  plunger.  A-  insurance  again-t  failure  of  the  plungers 
to  return  when  o]>erated  In-low  the  s)K-ed  at  which  centri- 
fugal force  is  adequate  (about  UK)  rpm  I  a  simple  spring 
tv|K-  plunger  return  mean-  i-  incor|xi|-atcd. 

In  the  variable-delivery  ty|x-  of  pump,  two  bank- 
plunger-    each    are    arranged    in    a    -ingle    rotor    with    the 
plunger-  in  the  two  bank-  in  parallel  relation.     Kach  ]• 
parallel  cylinder-  i-  in  ojx-n  communication  by  mean-  of  a 
drilled  pa-sige  in  the  rotor. 

The  plunger   lollei-  "I   e.ieh  bank  roll  again-t  a   s«-| 
elliptical     reaction     ring.        The    two    ring-    are 


NOVKMBKK   I1' IK 


mounted  in  the  pump  housing  and  are  geared  together 
through  bevel  gears  and  pinions  so  that  they  rotate  in  oppo- 
Mte  directions  in  response  to  rotation  of  the  volume  control 
ipinion. 

In  connection  with  the  hydraulic  motor  applications  of  the 
Superdraulic  pump  principle,  three  lobe  cam  rings  instead 
of  elliptical  reaction  rings  have  been  specified,  thereby  pro- 
viding three  plunger  strokes  per  revolution  and  providing 
a  high  reaction  angle  for  high  starting  torque. 

In  design  of  the  new  pump,  Superdraulic  engineers  have 
been  guided  by  four  major  principles — first,  the  necessity 
for  balance  between  the  pintle  and  the  rotor  and  the  plung- 
ers and  the  rotors ;  second,  that  the  plunger  actuating  mech- 
anism must  provide  a  maximum  number  of  plungers  per 
pump  while  the  plungers  must  make  two  displacement 
strokes  per  pump  revolution  instead  of  the  conventional  sin- 
gle stroke. 

Third  requirement  was  the  necessity  for  simple,  sensitive, 
manual  and  automatic  volume  controls  which  could  be  in- 
terchangeably employed. 

The  fourth  is  that  the  pump  structure  be  designed  to 
withstand  thousands  of  hours  of  operation  even  on  the 
lightest  hydraulic  oils. 

The  new  Superdraulic  pump  is  said  to  eliminate  the  neces- 
sity for  costly  and  cumbersome  intensifiers  and  accumula- 
tors in  obtaining  its  high  pressures.  It  also  generates  the 
desired  tonnage  for  hydraulic  presses  without  the  aid  of 
large  cylinder  assemblies.  The  pump  provides  a  full  range 
of  applications,  since  the  delivery  at  1200  rpm  ranges  from 
0  to  17  gallons  per  minute.  Greater  delivery  is  possible 
through  multiple  unit  installations. 

Leakage  is  the  principal  source  of  heat  in  some  high 
pressure  pumps  and  results  in  a  reduction  of  over-all  ef- 
ficiency. Its  effect  is  minimized  as  speeds  increase.  In 
the  radial-type  pump  leakage  is  used  to  lubricate  axles, 
rollers  and  the  joint  between  the  plunger  and  the  axle. 
This  is  accomplished  by  drilled  holes  which  provide  pas- 
sages from  the  slots  to  the  "tongue"  which  fits  into  a  mating 
slot  in  the  axle,  thereby  providing  a  path  for  lubrication  of 
moving  parts. 

In  addition,  a  small  circulating  oil  pump  is  incorporated 
in  the  variable  delivery  pump  assembly  for  the  purpose  of 
circulating  oil  direct  from  the  oil  tank  through  the  pump 
housing  back  to  the  tank.  This  provides  sufficiently  low 
pump  housing  temperatures  when  heat  conditions  are  at 
the  maximum  at  full  pressure,  zero  delivery.  END 


r 

a""" ' 


Aircraft  Feature  New  Laminates 

(Continued  from  page  34) 


1 

_J 


fcueegeed  together  on  a  sheet  of  aluminum  coated  with 
plastics  parting  lacquer.  A  second  sheet  of  aluminum,  simi- 
larly coated,  completes  the  "sandwich."  The  "sandwich" 
assembly  is  then  placed  between  heavy  Kirksite  dies  which 
have  been  preheated.  Weight  of  the  Kirksite,  plus  supple- 
mentary lead  ingots,  produces  the  necessary  laminating 
pressure  of  approximately  15  psi.  Complete  polymerization 
of  the  styrene  is  accomplished  at  265°  F  in  30  min.  When 
production  demands  warrant,  Northrop  engineers  plan  to 
use  hydraulic  presses  with  heated  platens  for  producing 
this  tank  backing  material. 

The  plastics  laminate  has  proved  far  superior  to  aluminum 
in  this  backing  application.  It  is  lighter  and  stronger  than 
the  metal  which  it  replaces,  can  be  produced  either  flat  or 
in  corrugated  form,  and  in  military  aircraft  will  withstand 
>r»j  rctile  penetration  without  appreciable  weakening  or 
tearing. 

The  heat  insulating  washers  are  approximately  2"  in 
lia,  and  washers  with  as  many  as  50  laminations  have  been 


PLASTICS 


85 


IN  GOLD,  SILVER  OR  COLORS 


FOR 

DURABLE 
UPHOLSTERY 
FABRICS 


Fabrics  woven  of  SARAN  BY  NATIONAL 
combine  beauty  and  intense  color  with  rugged 
durability.  SARAN  fabrics  won't  absorb  dirt 
or  grease  are  not  affected  by  acids, 

alcohol  and  most  other  chemicals.  For  furni- 
ture, auto  seat  covers  and  many  similar  prod- 
ucts. SARAN  has  opened  the  door  to  new 
and  wider  markets 


produced.  Due  to  the  thermosetting  nature  of  the  photic: 
used,  the  washer-  may  be  subjected  to  high  heat,  withou1 
injury.  At  the  same  time,  the  low  heat  conductivity  of  th< 
material  acts  to  supply  superior  insulation  between  hot  en- 
gine mounts  and  the  airframe  proper. 

Other  all-plastics  components  developed  specifically  foi 
the  XB-35  include  the  largest  free-blown  methacrylate  bub- 
ble canopy  ever  completed.  This  is  located  on  the  uppei 
portion  of  the  leading  edge,  and  forms  the  entire  canopj 
cover  for  the  pilot's  compartment.  It  measures  111".  Th« 
Northrop  F-15  camera  plane  has  a  two-piece,  free-blowi 
canopy  of  the  same  material,  measuring  145". 

Perhaps  the  best  illustration  of  the  cost-and-weight-sav 
ing  possibilities  of  plastics  in  aircraft  is  the  carburetor  in 
take  air  duct.  This  part,  approximately  2'  wide,  1'  thick 
and  5'  long,  is  now  being  made  completely  of  lamin;itec 
Fiberglas-styrene.  The  original  component,  made  of  alunii 
num,  weighed  23J^  Ib  and  cost  $355  to  produce;  the  lami 
nated  part  weighs  7'/i  Ib  and  its  production  cost  is  $65. 

A  new  plastics  laboratory  for  research  is  currently  utulei 
construction  at  Northrop.  Company  design  engineers' an 
fully  convinced  that  plastics  have  a  definite  place  in  ftitun 
aircraft  construction,  not  as  a  substitute  material,  but  a: 
the  best  material  available  for  certain  types  of  installations 
They  are  attacking  the  problem  from  the  logical  angle  o 
carefully  controlled  research  and  development.  i  M 


Color  in  Plastics  Tableware 

(Continued  from  page  56) 


Carson,  Pirie,  Scott  &  Co.,  Chicago,  is  among  the  depart 
ment  stores  offering  this  set,  which  it  reports  as  being  t 
fast-moving  item. 

Greater  popularity  is  evidently  enjoyed  by  the  pastel 
toned  dishes  than  by  the  original,  ivory-colored  sets. 

The  distribution  of  Watertown  Ware  is  handled  bj 
George  I.,  \\eigl  &  Co.,  New  York  City,  which  ha 
ducted  an  interesting  merchandising  campaign  on  the  ]>n  «l 
uct.  In  order  to  familiarize  the  consumer  with  molamiw 
tableware,  this  distributor  worked  out  a  co-operative  adver 
tising  campaign  with  some  of  the  large  department  Mores 
including  Macy's,  Best  &  Co.,  Gimbel's,  and  Blooming 
dale's,  in  New  York ;  ( i.  Fox,  in  Hartford,  Conn.;  Maiulel's 
and  Carson,  Pirie,  Scott  &  Co.,  in  Chicago,  and  others. 

In  addition,  advertisements  have  been  placed  in  man 
zincs  which  have  special  appeal  to  the  home-maker 
as  Good  Housekeeping,  Parents,  etc.    In  all  of  these  i 
the  copy  spotlights  the  fact  that  these  dishes  are  m. 
plastics.    And  to  stress  the  possibilities  of  Watcrlown  II  ard 
for  outdoor  use.  publicity  was  released  by  the  V. 
pany  to  such  publications  as  Yachting,  and  Boat  &  I 
men  I  AY 

There  were  also  the  publicity  stories  which  appeared  I 
the  women's  pages  of  outstanding  daily  new-paper-,  tcllin 
the  story  of  this  mrtamine  tableware:  the  \\cigl  tin 
feels  that  publicity  of  this  type  has  excellent  "pulling  |" 

Furthering  the   merchandising  campaign,  the  agci 
tin    company  have  conducted  surveys  of  the  potential  marj 
kets  for  melaminc  dishes,  ajld  consultation-  with  ofti, 
various   industrial  organizations.     For  example,  they  di-J 
!  dii.-ctly  with  purchasini:  agents  of  commercial  ship- 
ping lines  the  most  efficient  means  of  fulfilling  the  lines 
requirement    in   this   regard.      State    institution-   aloi 
o.i ding  to  one  market  survey,  have  annual  budget-  adding 
Up  to    -e\eral    million   dollar-   for    purcha-e   oi    chinauare 
which   in   itself   indicate-  a   large   jxitential   market   for   th< 
pl.-i-t  \nd   till-,  with   the  addition  of   van. ill 

potential   market-,   provide-  a   really  outstanding  sco; 

Me  sales  of  this  merchandise.  '  '•' 


M 


PLASTICS 


NOVKMHKK 


Extrusions 

(Continued  from  page  68) 


either  side  of  one  leg  end.  Being  small,  they  cured  quickly, 
thus  minimizing  danger  of  deformation  on  the  conveyor. 

Fabrication  time  for  the  original  die  took  30  hours ;  prov- 
ing time  occupied  twice  that  length  of  time. 

Another  extrusion  job  in  which  utility  and  sane  produc- 
tion profiles  are  combined,  is  the  firm's  linoleum  and  wall 
board  molding  (patent  pending).  Formed  in  two  strips  of 
Tenite  II  (H2),  subsequently  to  be  snapped  together,  high 
moisture  resistance  is  established. 

Used  in  lieu  of  conventional  pressed  hardboard  base- 
boards, the  strips  are  also  highly  resistant  to  abrasion,  chip- 
ping or  cracking.  However,  the  color  runs  all  the  way 
through,  insuring  permanent  beauty.  Flexibility  facilitates 
installation,  and  resiliency  permits  snapping  the  upper  strip 
to  the  lower  one,  which  is  nailed  in  place. 

Nail  heads  are  concealed  by  the  snap-on  section,  which 
makes  it  feasible  for  inexperienced  craftsmen  to  perform  the 
installation.  As  nail  heads  are  hidden,  puttying  is  avoided. 

Curves  in  wider  sections  are  held  true  by  lowering  the 
conveyor  as  in  extruding  the  table  edge.  While  legs  are 
bent  in  the  forms  of  hooks  and  tongues,  the  projections  are 
small,  and  cure  rapidly.  But  because  a  good  fit  was  essen- 
tial to  the  interlocking  principle  of  the  device,  air  jets  are 
applied  directly  to  these  small  parts. 

Thirty-six  hours  were  expended  in  fabricating  each  of  the 
original  dies ;  proving  time  was  about  25  hours  for  each. 

In  extruding  a  patented  interlocking  strip,  a  closure  for 
cabinets,  somewhat  like  a  roll  top  desk  curtain  (see  "Hous- 
ing Looks  to  Plastics,"  plastics,- May  1946),  the  main  prob- 
lem was  to  prevent  warping  of  the  sections.  Until  the  design 


was  perfected,  this  tendency  manifested  itself  in  four  direc- 
tions— up  and  down,  and  right  and  left,  as  the  material 
moved  on  the  conveyor. 

Unlike  a  desk  curtain,  the  closure  is  an  all-plastics  assem- 
bly, with  no  fabric  backing  to  stabilize  the  slats.  Each  strip 
hinges  upon  its  two  neighbors,  and  the  assembled  curtain 
doubles  upon  itself,  disappearing  into  recesses  at  tops  of 
cabinets.  It  also  rolls  into  a  compact  bundle. 

Experimentation  showed  that  the  tendency  to  warp  could 
be  attributed  to  varying  thicknesses  in  the  section.  Kerr 
overcame  this  difficulty  by  redesigning.  All  sections  eventu- 
ally were  held  to  as  nearly  uniform  thickness  as  was  com- 
patible with  engineering  requirements.  The  new  design 
cured  evenly,  without  special  air  jets.  Original  die  fabrica- 
tion took  40  hours;  proving,  because  of  changes,  100  hr. 

As  with  many  extrusions,  design  development  underwent 
several  phases.  Originally,  a  curved  strip  was  designed, 
with  a  hook  arid  bulb  hinge.  The  heavy  nature  of  the  bulb 
caused  it  to  warp,  and  the  lightness  of  the  hook  invited 
deformities  during  the  cure. 

To  overcome  warping,  the  material  was  reduced  by  ex- 
truding the  bulb  over  a  mandril,  as  in  fabricating  a  tube. 
But  thinness  of  the  material  then  tended  toward  uneven 
distribution,  resulting  in  numerous  rejections.  Further,  on 
application  the  hook  disjoined  itself  from  the  bulb  in  per- 
forming sharp  curves,  as  when  rolled  compactly. 

Several  design  revisions  were  made,  until  the  present 
strip  was  developed  in  Tenite  II  (H5),  chosen  for  its  rigid- 
ity and  appearance.  The  smooth-working,  dependable  ex- 
trusion lends  itself  to  several  interlocking  applications.  In 
addition  to  being  applied  both  horizontally  and  vertically  as 
a  desk  and  cabinet  closure,  it  has  been  fitted  into  wardrobe 
trunks,  stood  vertically  to  form  a  rigid  lamp  pedestal  and  has 
been  fashioned  into  the  external  sides  of  a  handbag. 

An  outstanding  example  of  economy  in  extrusions  was  the 


SPECIALISTS  IN  SILVERING 

r 

With  over  10  years'  experience  in  specialized 

/ 

silvering  to  exacting  military  and  custom 
specifications.  We  are  prepared  to  deliver  high 
quality  and  uniformity  of  finish  on  molded  and 
fabricated  plastics. 

Inquiries  will  receive  friendly  and  prompt 

attention. 


NEW  JERSEY  SPRAYED  PRODUCTS  CO.,  INC. 

250  MILL  STREET 
BELLEVILLE  9,  NEW  JERSEY 

-rrt    r-i-n   u»Nh.  irs*          f»^l   I   f-\  Jl  I   10      A      1    ^^**^"** 


TELEPHONES:  BELLEVILLE  2- 


|4062 


NOVEMBER  1946 


PLASTICS 


87 


complete 
plastic 
display 
fabrication 


Like  sparkling  crystal,  this 
attractive  lucite  display  stand 
represents  a  distinctive  achiev- 
rnent  in  plastic  design,  fabrica- 
tion, assembly  and  engraving. 
It  is  a  typical  example  of  Print- 
loid's  versatile  ability  to  pro- 
duce outstanding  display  units 
for  some  of  America's  leading 
firms. 


DtfT.  P 
93  MERCER  STREET,  NEW  YORK  12.  N.  Y. 


trk  your  A  a  lex 

WITH  MOULDED  PLASTICS 


•  Moulded  Plastics  —  put  to 
use  wisely  —  can   cut  your 
manufacturing   costs,  sparlc 
your  sales. 

•  It's  our  business  to  select 
the  right  plastic  for  the  job 
at  hand  —  transform  that  raw 
plastic  into  a  finished  product 
which  will  meet  your  demands 
for  greater  sales  appeal, greater 
strength  and  durability. 


•  Your  work  at  Magnetic 
Plastics  is  custom  moulded 
by  the  finest  craftsmen  to 
your  precise  needs  or  spec- 
ifications. 

•  Perhaps  there's  a  plastic 
answer  to  your  problem. 
Just  send  photo,  sample  or 
drawings,  and  we'll  tell  you 
quickly  if  it  can  be  made 
in  moulded  plastics. 


mOtff  PLASTICS 


1»00   tUCUD    BUIIDINO      •      CIEVUAND    15.  OMK 


production  of  grommets  for  Douglas  Aircraft.  Thirty-nine 
different  grommets  were  produced  through  three  dies  cost- 
ing merely  $150  each — a  total  of  $450. 

The  grommets,  for  use  in  sheet  metal  bulkheads  through 
which  is  passed  a  wire,  or  bundles  of  wire,  were  required  in 
13  varying  ring  diameters  ranging  from  3/16"  to  3".  Fur- 
ther, the  ring  diameters  were  required  with  three  different 
grooves  to  suit  as  many  variable  bulkhead  thickne-*e*. 
Three  external  designs  were  specified. 

To  effect  the  economy,  Kerr  fabricated  three  profiles  to 
meet  external  design  requirements.  Each  had  the  smallest 
groove  dimension  for  its  design.  As  extrusions  came  from 
the  machine,  they  were  cured  in  form  of  coil  springs. 

\\hen  grommets  with  larger  grooves  were  desired,  the 
extrusion  was  pulled  across  a  circular  saw  blade,  which 
machined  the  niche  to  proper  size.  To  achieve  variable  ring 
dimensions,  the  coiled  extrusion  was  wrapped  around  a  man- 
dril of  the  specified  diameter,  and  cut. 

The  cutting  involved  a  compound  angle.  To  simplify  in- 
stallation and  eliminate  gaps  which  would  furnish  inade- 
quate protection  for  bundles  of  fine  wire,  the  cut  was  slanted 
against  the  diameter  and  diagonalled  against  the  circumfer- 
ence of  the  extrusion. 

In  this  manner,  a  large  number  of  small  quantities  \va* 
provided,  economically.  The  wide  versatility  of  the  three 
extrusions  represented  a  considerable  financial  saving  as 
compared  with  thirty-nine  different  mold  dies,  which  other- 
wise might  have  been  necessary.  Making  of  the  first  dies, 
and  their  proving,  consumed  approximately  12  hours  each. 

I'M;  of  Tenite  II  (H2)  provided  great  improvement  over 
rubber  or  fibre  tubing  previously  utilized  by  Douglas  for 
grommets.  Rubber  grommets  had  been  dislodged  by  fric- 
tion and  were  subject  to  extreme  wear  from  vibration  and 
flexing  when  in  contact  with  wire  bundles.  Fibre  tubing 
called  for  expensive  tooling,  and  was  confined  to  small 
diameters  because  of  the  large  amount  of  force  necessary  in 
forming.  The  nature  of  fibre  also  required  bench  installa- 
tion before  assembly  of  part*. 

Douglas  found  that  the  cellulose  acetate  butyrate  grommet 
could  be  quickly  and  easily  installed  or  removed.  It  is  not 
dislodged  by  friction  or  vibration,  is  lightweight,  durable. 

In  extruding  beads  for  necklaces,  light  tubing  for  chil- 
dren's pea  shooters,  suit  case  handles  or  similar  consumer 
knick-knacks,  about  any  acetate  with  wide  color  range  will 
do. 

Tubular  novelties  are  extruded  after  the  manner  of  fab- 
ricating pipe,  which  is  to  force  the  heated  material  around  a 
mandril  in  a  circular  die.  Air  pressure  in  the  tubing  sup- 
port* the  shape  and  assists  in  cooling.  l'*ually  a  die  of 
larger  diameter  than  the  specification  is  employed.  Speed 
<if  the  conveyor  exercises  tension  which  stretches  the  ex- 
trusion to  size. 

Once  the  tube  is  cured,  it  may  be  cut  to  required  length*. 
For  beads,  J4"  tube  may  be  cut  into  1/16"  sections.    \ 
methods  of  stringing  beads  produce  variable  necklace  de- 
signs. 

In  fabricating  tubes,  Kerr  finds  that  seven  variables  may 
be  considered.  These  arc :  Speed  of  extruder ;  rear  cylinder 
heat:  front  cylinder  heat;  die  heat;  conveyor  *|>ced  ;  con- 
veyor height  in  relation  to  the  die :  and  air  pressure  in  the 
tube.  However,  different  combinations  of  these  variables 
may  produce  identical  result*. 

If  speed  of  tin'  extruder  screw  i>  increased,  all  heat*  must 
be  raised.  The  required  temperatures  are  thus  transmitted 
to  the  resin,  imw  passing  more  rapidly  through  the  machine] 
<>liviou-.ly,  the  conveyor  *|>ecd  11111*1  IK-  stepped  tip  pn.pi 
tionately,  to  draw  the  more  rapidly  extruded  tube  to  li 

If  a  pipe  of  greater  wall  thickness  is  to  U-  i';dn  trat 

mum  practice  to  speed  the  extruder,  lower  the  three 
heats,  reduce  air  pre**ure  anil  leave  conveyor  *i>eed 
unchanged. 

Another  variable,  which  would  not  affect  tube  *i/< 


vs 


IT  tSTf <  * 


NOVKMHKK   1H46 


reduce  air  pressure  in  the  tube  while  increasing  die  heat. 
With  hotter,  more  pliable  material,  less  air  pressure  is  need- 
ed to  hold  the  tube  to  roundness  and  diameter. 

It  is  also  usual  to  carry  tubular  structures  on  rollers  some 
distance  from  the  die.  Such  rollers  help  in  establishing 
shape  by  being  grooved  to  contour  of  the  tubing,  and  they 
also  expose  the  tube  evenly  to  the  air.  It  cools  throughout 
its  circumference,  with  minimized  danger  of  warpage. 
When  partly  cured  tubing  contacts  the  flat  conveyor  belt,  a 
flat  under-side  may  result. 

Piano  type  hinges  in  plastics  materials  represent  one  of 
the  commonest  extrusions.  They  consist  of  a  flat  strip,  with 
a  tube  at  one  side  for  the  hinge  pin.  Lobes  and  screw  holes 
are  punched  in  post  machining.  Through  use  of  Lumarith 
X  and  Tenite  II  (H2),  Plastic  Process  has  produced  hinges 
with  tensile  strength  of  115  Ib  per  linear  inch. 

Due  to  the  great  amount  of  die-proving,  it  is  economical 
for  a  plant  to  operate  its  own  machine  shop  in  close  prox- 
imity to  its  extruding  equipment.  Plastic  Process  avoids 
time  lags  by  having  the  two  departments  in  the  same  room. 

An  understanding  of  the  laws  of  hydraulics  is  helpful  in 
die  production.  Like  fluids,  heated  resins  being  molten  will 
funnel  through  tapered  orifices  more  readily  than  through 
square-shouldered  holes. 

In  casting  a  rod  with  a  thin  wing  at  one  side,  it  is  practice 
to  square  the  shoulder  for  the  rod  orifice  and  to  taper  the 
wing  portion  of  the  die.  The  flow  is  thus  expedited  in  the 
thinner  flat  portion,  where  otherwise  it  might  be  retarded. 

As  liquids  flow  in  round  streams,  this  characteristic  in 
heated  plastics  materials  is  overcome  by  machining  con- 
caved sides  into  die  orifices  for  square  extrusions.  As  the 
cure  takes  place,  the  material  flows  into  the  desired  square 
form.  The  same  procedure  is  sometimes  followed  in  ex- 
truding an  L-form,  or  various  other  thick,  flat-sided  profiles. 

While  the  company  used  Tenite  II  for  extrusions  de- 
scribed herein,  it  utilizes  many  other  thermoplastics,  as  well. 
Among  these  are  Styron  (polystyrene)  for  high  dielectric 
strength  and  end  use  in  elevated  temperatures,  Ethocel 
(ethyl  cellulose)  for  impact,  Geon  (vinyl  resins)  for  flexibil- 
ity and  chemical  resistance,  and  acrylics  for  certain  purposes 
requiring  high  optical  properties. 

In  making  extrusion  progress,  the  firm  has  developed  its 
own  method  of  dyeing  cellulose  acetate  granules  prior  to 
extrusion,  but  is  withholding  announcement  on  the  process, 
pending  grant  of  a  patent.  Likewise,  the  company  is  at 
present  keeping  "under  wraps"  its  method  for  rounding 
edges  of  necklace  beads,  and  an  automatic  extrusion  cutting 
machine.  END 


f 

JFui.iiiii.- 


Plastics  Cases  for  Museums 

(Continued  from  page  5J  i 


is  removed  from  its  temporary  shaping  position,  the  perch 
and  bird  are  fastened  to  it  and  it  is  then  tacked  in  its  per- 
manent location. 

For  electrical  welding  of  jointures,  the  special  soldering 
iron  has  a  tapering  point.  Heat  is  radiated  from  the  iron's 
larger  diameters,  which  helps  prevent  the  point  from  burn- 
ing the  material.  As  a  further  precaution  against  over- 
heating, the  available  110  v  current  is  reduced  by  a  150  w 
lamp.  Welding  is  performed  on  another  turntable. 

Extending  roof  selvages  are  trimmed  by  hand  shears, 
after  which  welded  jointures  are  run  down  on  a  4"  grinder 
of  mixed  carborundum  and  sandstone.  At  low  speed,  the 
small  abrasive  wheel  develops  only  a  slight  heat. 

Welds  are  next  buffed  with  fine  sandpaper.  Wherever 
surfaces  appear  to  be  roughened  in  grinding  or  sanding,  a 
brush  treatment  of  acetone  is  applied.  The  solvent  cuts 
projections  in  rough  surfaces,  thereby  restoring  the  ma- 
terial's optical  property.  END 


Do  not  accept  itibslitHtcs. 
There  is  ml)  onephstic 
—CELLO. PLASTIC. 


N0w  available  in  many 

beautiful  colon  and 

for  every  purpose. 


Brings  New  Colorful  Beauty  and  Durable  Protection  to 
FLOORS*  WOODWORK*  WALLS  *  EXTERIORS 

oils  combined  with  the  finest 
paint  pigments.  ACello- Plastic 
product  is  available  for  almost 


Plastic  is  now  prepared  in 
liquid  paint  form  for  use  in 
home, office,  store, and  facto ry . 
This  has  come  about  through 
the  formulation  of  synthetic 
resinswithspeciallyprocessed 


any  type  of  finish  or  surface. 
Does  not  chip  or  Crack! 


BRILLIANT*  SMOOTH  *  TOUGH*  DURABLE 

FOR  FIOOP<»  Cello-Plastic  ^transparent/  is  I  non-skid  plastic 
Wl*.  rtvWKa  finish  foraU  tvpes  Of  floors.  Thi,  amazing  new 
'««njem  gives  floors  a  "cellophane-like"  Plastic  finish.  Eliminates  pores  thai 
absorb  dirt,  thus  making  floors  easy  to  clean.  Ideal  for  all  surfaces  including 
wood,  concrete,  linoleum,  asphalt,  tile  rubber,  composition,  etc.  Eliminate* 
u'timg  ana  foltshint.  Unexcelled  for  marine  use. 

EXTERIOR      T*"s  mo<*ern  finish  is  a  severely  tested  product 
k     that  surpasses  old  fashioned  type  house  paints. 

I  lamented  with  Titanium  Dioxide,  the  whitest  and  best  covering  pigment, 
combined  with  kettle  processed  linseed  oils  and  plastic  resins,  it  makes  a  rich, 
colorful,  lasting  coating.  Makes  homes  and  buildings  outstanding.  For  use  on 
wood,  stucco,  brick  or  shingle. 

INTERIOR     Brings  new  glamour  into  homes — protect  floors, 
„     .  woodwork,  furniture,  etc.,  with  its  long-lasting. 

cellophane-like  Plastic  finish.  Easy  to  apply— flows  smoothly— leaves  no 
brush  marks — self  leveling. 

Inquiries  from  Exporters  and  Dealers  Solicited 

Product  liability  under-written  by  one  of  America's 
largest  insurance  companies. 


CELLO-PLASTIC  CHEMICAL  CO. 

417-419  BLVD.  OF  ALLIES,  PITTSBURGH  19,   PA. 


NOVEMBER  1946 


PLASTtCS 


OPEN 

TIME 

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AMERICAN   PHOTOCOPY   EQUIPMENT   CO. 
2M»  N.  CUrV  St..  I>pC  PA  1 1*.  Chk»c°  1 4.  III. 


LETTERS.  ORDERS.  DRAWINGS. 

TRACINGS.  SPECIFICATIONS. 

INVOICES.  RECEIPTS.  CHARTS. 

HUE  PRINTS.  CONTRACTS. 

(over  100  others) 


Alio  continuou* 
tabintt  modtli  for 


Greeting  cards,  made  by  Wilhamsburg  Publishing  Co..  fea- 
ture typical   decorative  attachments  oi  acetate  or  nitrate 


Decorating 
Greeting  Cards 


AMERICA'S  MOST  WIDELY  USED  PHOTOCOPY  EQUIPMENT 


STARTING  before  the  war,  the  vogue  for  use  of  plastics 
in  the  greeting  card  industry  has  gained  rapid  impetus, 
although  temporarily  retarded  by  lack  of  materials  during 
the  war  years.  As  supplies  become  more  plentiful,  however, 
it  is  exacted  that  there  will  l>e  an  increase  in  decoration  on 
the  more  exix.-n.sive  greeting  cards,  as  well  as  on  the  novelty 
cards. 

Cellulose  acetate  or  cellulose  nitrate  are  used  for  attach- 
ments of  this  type.  They  are  generally  die-cut  from  sheets 
rather  than  molded,  and  are  made  in  such  form*  as  miniature 
candles,  birthday  cakes,  charms,  cigarettes,  valentine  hearts, 
and  a  variety  of  others. 

The  color  and  lightweight  qualities  of  plastics  render 
them  particularly  adaptable  for  greeting  card  requirements, 
and  their  ease  of  handling  and  manipulation  constitute-  ,m 
important  factor  in  a  mass-production  industry  where  every 
attachment  must  IK-  affixed  by  hand.  Contrast  of  color-  ami 
liackurouml  is  eye-catching,  and  the  embossed,  glistening 
surface  creates  a  bas-relief  effect  that  makes  the  card 
outstanding. 

\tt.ielitiieiit-  are  cut  in  male  or  female  dies  made  of  steel, 
bnm/e  or  other  non-ferrous  metal.  Forming  and  cutting 
comprise-  a  single  o|XTation.  the  plastics  being  preheated  on 
licit  plates.  The  cards  are  die-cut  and  flanges  or  tab 

I   under   the  die-cut   so  that  they  are  concealed,  the 
surface  bulging  outward. 

The   sheet    method   of   attachment    i-   a   compromise,    tor 
economical  reasons.     A  much  better  method  would  be  injec- 
tion molding,  which  would  provide  the  attachment  with  a 
flat    posterior   and   a   bulging   anterior   side — and   the   back 
could  U-  pasted  to  the  card  without  necessity  for  flanges  or! 
t.ilis.  uist  as  tlat  attachments  are  pasted  with  liquid  a< 
I  be  cost  of  injection  molding,  however,  is  still  considered 
prohibitive  lor  this  purp.  \erage  order  for  greeting 

cards  runs  to  approximately  50,000  pieces,  which  is  20% 


I'I..\STH'S 


NOVKMHKK   1946 


less  than  the  minimum  volume  needed  to  pay  for  the  cost 
of  molding. 

As  it  is,  the  cost  of  plastics  attachments  is  15%  to  20%  of 
the  cost  of  the  entire  product,  including  application.  Adding 
the  attachment  generally  increases  the  retail  price  of  the 
card  by  100%.  Thus  the  price  of  a  five-cent  card  jumps  to 
ten  cents  when  plastics  are  added,  cost  of  the  attachment 
being  $3  to  $4  per  thousand.  A  sheet  of  15-gauge  acetate 
costs  about  75  if ;  it  can  therefore  be  readily  appreciated  that 
molding  would  pay  only  for  rare,  high-priced  items  on  the 
dollar-a-card  level,  as  the  cost  of  the  die  alone  would  exceed 
the  value  of  the  average  order. 

According  to  Arthur  Frisch,  industrial  designer  and  man- 
ufacturer of  specialties  in  this  field,  cost  is  the  only  barrier 
to  expanded  use  of  plastics  in  the  greeting  card  industry. 
Yet  even  this  limitation  has  not  kept  the  buying  public  from 
registering  a  heavy  preference  for  this  type  of  greeting  and 
novelty  card. 

Plastics  are  also  used  in  the  form  of  frosted  and  clear 
Cellophane  to  form  windows  and  "peep-holes."  S.  Shannon, 
of  Greeting  Card  Industries,  says  that  plastics  would  be  a 
welcome  improvement  on  the  pulverized  glass  used  to  repre- 
[sent  snowflakes  on  Christmas  cards.  The  glass  particles 
cut.  and  can  be  rubbed  off  too  easily. 

There  is  a  type  of  novelty  card  that  specializes  in  unusual 
effects  and  is  distinct  from  greeting  cards  in  function  and 
appearance.  One  example  is  a  card  to  which  is  affixed  a 
miniature  cellulose  acetate  phonograph  record,  3"  wide, 
which  can  be  removed  and  played  on  a  phonograph,  selec- 
tions being  appropriate  to  the  occasion,  such  as  "Happy 
Birthday  To  You."  The  records  cost  3<f  each.  Plastics 
charms  of  all  sorts  fall  into  this  category,  these  items  being 
slanted  to  a  more  confined  market  than  is  the  greeting  card. 

The  potential  market  for  plastics  in  the  industry  is  not 
relatively  large,  but  executives  state  that  it  is  growing.  The 
industry  itself  has  expanded  impressively  since  about  1933, 
having  been  started  about  1900  and  reaching  a  volume  peak 
in  1936.  After  a  recession,  business  picked  up  again,  and  hit 
(a  new  high  in  1937. 

The  war  years  spurred  demand  to  unprecedented  levels. 
Some  15,000,000  people  were  "dislocated"  by  work  in  war 
industries.  Greeting  cards  went  to  relatives  and  friends 
who  had  out-of-town  jobs;  wedding  anniversary,  birthday, 
Christmas,  illness  and  convalescence  cards — all  were  in  de- 
mand. There  was  a  veritable  avalanche  of  greeting  cards  of 
[all  sorts  to  members  of  the  armed  forces. 

Shannon  foresees  increased  demand  for  plastics  in  the 
industry  in  the  immediate  future ;  quantity  production  will 
lower  cost  per  piece,  he  added,  and  he  stressed  the  willing- 
ness of  the  greeting  card  industry  to  co-operate  with  the 
plastics  industry  in  creating  new  ideas.  The  possibilities  of 
plastics  in  this  connection  have  hardly  been  tapped,  -he 
stated,  for  the  eye-appeal  of  plastics  makes  it  desirable  not 
only  as  an  application  to  the  card  but  also  for  packaging, 
racks,  and  display  stands  of  a  decorative  nature.  END 


\\ 


Plastics  and  Die  Castings 

(Continued  from  page  44) 


Most  radios,  whether  console,  portable  or  automobile 
models,  have  molded  plastics  components,  some  used  in  close 
association  with  die  castings.  This  is  especially  true  in  au- 
tomatic tuning  units  for  automobile  radios  and  in  sets  which 
include  record  players  and  changers.  Makers  of  changers 
are  very  largely  dependent  upon  die  cast  components,  but 
they  also  put  molded  plastics  to  good  use,  especially  as 
dielectric  and  decorative  elements.  The  closely  related  juke 
box  is  replete  with  both  plastics  and  die  castings,  applied 
bull i  as  interior  and  as  exterior  components. 

Manufacturers    of    business    machines    invariably    make 


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PLASTICS 


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molded  plastics  and  die  castings  serve  their  needs  eftec 
lively,  often  for  scores  of  parts  and  with  the  two  type 
of  products  in  quite  close  association.  Strictly  mechanica 
parts  are  likely  to  be  die  cast,  but  where  a  dielectric  i 
needed  or  a  colorful  or  transparent  exposed  part  is  wanted 
plastics  are  applied  effectively  and  economically. 

Even  makers  of  machine  tools  and  of  other  machines,  M 
as  those  for  the  textile  industry,  are  applying  molded  plastic; 
and  die  cast  parts,  in  control  units,  for  example,  to  supple 
ment  other  components.  Usually,  the  plastics  serve  eithei 
as  dielectric  elements  or  as  buttons  or  handles  that  are  color- 
ful  and  agreeable  to  the  touch.  Die  castings,  however,  in 
eluding  gears,  cams,  hand  wheels,  ht>u>inj;s.  dials,  pullies  am 
elements  of  control  units,  serve  as  mechanical  components 

It  would  not  be  difficult  to  multiply  specific  examples  o 
plastics  and  die  casting  applications  in  the  fields  already 
mentioned,  as  well  as  in  others,  but  those  cited  above  provide 
ample  evidence  that  the  two  classes  of  parts  each  suppleinen 
the  other  in  most  useful  and  effective  combinations.  1  lit 
metal-working  industry  buys  and  applies  plastics  molding' 
in  prodigious  quantities.  It  fabricates  and  uses  die  casting 
for  its  own  needs.  Occasionally  one  type  of  part  displaces 
the  other  but  much  more  often  the  two  classes  of  product; 
supplement  each  other,  for  the  benefit  of  all  concerned.  ENI 


Models  Aid  Design 

(Continued  from  /><!(;<•  JS  i 


SQUARING  SHEARS  •  ARBOR  PRESSES  •  FOOT  PRESSES 
92  f*f,..«Tfrs 


only  partway  up  and  then  fall,  and  the  whirling  ribs  wouk 
trip  them  each  time  they  reached  bottom.  Here  again,  w 
pointed  out  that  if  the  spin  were  strong  enough  to  cause  trip 
ping,  it  would  also  be  strong  enough  to  generate  a  cent r if u 
gal  force  that  would  overcome  gravity  and  the  dice  \\ouk 
again  lodge  against  a  rib  and  be  carried  over  and  around 
And,  if  that  were  true,  the  same  tiling  would  happen 
fore — no  tripping.  The  customer,  however,  was  as  sure  of  hi: 
ground  as  ever,  and  so  we  adapted  the  model  to  incorporate 
his  requirement  for  a  spin  in  a  vertical  plane  by  providing  a 
new  L-shaped  base.  What  we  had  predicted,  hapix'iied  :  an 
trifugal  force  acted  in  the  same  way  as  in  the  first  model,  ex 
cept  that  one  die  was  tripped  once  at  the  start  of  the  spin 

That  left  the  customer  convinced  and  the  design  joh  ii 
our  hands.  \Ye  retained  all  the  contours  and  dimensional 
requirement  of  the  original,  but  eliminated  the  ril> 
hole  was  drilled  through  the  center  of  the  pin-shaft  of  the 
cup,  the  hole  being  small  enough  in  diameter  not  to  ailed 
the  In-ariiiR  of  the  shaft-end  in  the  hole  of  the  cup-holder  in 
order  not  to  appreciably  reduce  the  spinnaliility.  A  •-teel  pin 
thin  enough  for  a  loose  lit  was  inserted  through  the  hole 
in  the  cup's  pin-shaft,  wa^  anchored  in  the  bottom  of  the 
cup-holder  and  was  I  "-bent  over  the  top  to  arrive  al 
and  extend  down  near  the  side-wall  of  the  cup.  This  -teel 
pin  remains  rigid  and  fixed,  while  the  cup  revolve*, 
action  is  this:  When  the  cup  U  set  spinning,  the  di. 
centrilugally  thrown  up  again*!  ihe  intersection  of  *ide- 
\\all  and  covering  di*c.  They  are  lodged  there  and  are 
therefore  carried  around  with  the  spin.  When  they  n-.icli 
tin'  fixed  *teel  pin.  they  are  tripped  and  thrown  oil  into 
the  tioor  of  the  cup.  Since  the  cup  is  still  revolving,  the 
dice  are  again  thrown  up  to  the  *ide-wall,  are  again  carried 
around  to  the  steel  pin  and  are  again  tripped.  And  the 
action  rejx-at*  it*elf  until  the  spin  slow.*  down. 

There  arc  no  molding  difficulties  involved  in  this  design, 
but  we  pointed  out  to  the  customer  that  the  cost  per  piece 
would  be  comparatively  high  lx-cau*e  of  the  amount  of 
material  involved  and  IK-C.IU-C  of  the  fabrication  of  the  pin 
and  the  n«  *emhly  o|x-rations.  The  customer  felt. 

however,  that  he  now  had  exactly  what  he  wanted  and, 
since  hi*  tame  was  not  intended  to  IK-  popular-pi  iced,  the 
production  co*t  wa»  not  of  great  si^mlic.ii 


N<>\  KMMKK    I'M 


' 


overseas 


Research  and  development  work  on  polyvinyl  chloride  for 
footwear  continues  in  Britain,  with  some  progress  in  the 
production  of  suitable  plasticized  sheeting  and  appropriate  ad- 
hesives  for  cementing.  The  most  useful  cements  are  neoprene 
in  the  form  of  latex  and  hycars  (butadiene-acrylates)  in 
solvent  solutions.  Unfortunately,  the  supply  position  of  both  satis- 
factory polyvinyl  chlorides  and  cements  prevents  the  carrying 
out  of  large  scale  development  work  by  the  footwear  industry, 
despite  pressure  being  exerted  by  the  Board  of  Trade.  When 
considering  the  slow  progress  made  in  the  use  of  polyvinyl 
chloride  compositions  for  outer  soles  and  heels,  it  is  necessary 
to  take  into  account  the  somewhat  destructive  criticism  of  the 
shoe  trade  and  the  antipathy  towards  plastics  shown  by  certain 
manufacturers.  This  attitude  is  due  almost  entirely  to  the  dis- 
couraging results  obtained  in  the  past  when  no  really  satisfac- 
tory cements  were  available,  as  well  as  to  the  variable  physical 
FToperties  of  the  polyvinyl  chloride  sheeting.  Shoe  manufac- 
turers have  pointed  out  that  in  comparison  with  rubber  com- 
positions, plastics  show  a  greater  tendency  to  deform  under 
stress  and  have  ageing  properties  inferior  to  those  of  rubber. 
A  recent  report  on  leather  substitutes,  issued  by  the  Ministry  of 
Supply,  contains  an  analysis  of  the  results  of  wearing  tests  car- 
ried out  on  plastics,  from  which  it  is  apparent  that  polyvinyl 
chloride  uppers  have  not  proved  very  satisfactory,  although 
polyvinyl  chloride  molded  soles  and  heels  give  results  as  good 
as  the  finest  rubber.  According  to  the  official  report,  whereas  the 
plastics  polyvinyl  chloride  molded  soles  and  heels  were  worn 
for  several  months  with  little  sign  of  wear,  soles  and  heels 
made  from  polyvinyl  chloride  sheets  were  only  fairly  satisfac- 
tory. Incidentally,  the  general  experience  in  the  trade  is  that 
heels  made  of  this  plastics  wear  only  about  half  as  well  as  soles 
of  the  same  material. 

Vinyls  for  Shoe  Uppers 

Turning  briefly  to  shoe  uppers,  a  good  deal  of  interest  is  be- 
ing shown  in  polyvinyl  chloride  and  polyvinyl  chloride-acetate 
sheeting  for  tips  and  quarters,  and  in  the  use  of  polyvinyl  chloride 
pastes  for  the  coating  of  textiles  for  the  uppers.  It  is  considered 
in  trade  circles  that  the  pastes  probably  offer  more  promise 
than  does  the  plasticized  sheeting.  The  main  criticism  of  the 
latter  for  uppers  is  that  it  becomes  soft  and  inclined  to  flow  at 
high  temperatures,  and  exhibits  a  tendency  to  crack  at  low 
temperatures. 

Although  the  vinyl  polymers  are  not  the  only  materials  re- 
ceiving attention  in  the  British  shoe  trade  they  may  be  said  to 
be  the  most  interesting,  and  offer  the  greatest  promise,  al- 
though competent  authorities  agree  that  in  their  present  form 
they  seem  unlikely  to  be  serious  competitors  of  sole  and  upper 
leathers.  It  is  interesting  to  note  a  strong  trend  towards  the 
use  of  polyvinyl  chloride-acetate  fabric  reinforced  material  and 
vinyl  copolymer  yarns  for  knitting  into  nets  or  weaving  into 
fabrics.  These  nets  and  fabrics,  made  mostly  of  Vinyon  have 
received  favorable  notice  and  commendation  from  the  footwear 
trade  because  of  their  great  strength,  low  moisture-and-dirt- 
absorbency  and  pleasing  appearance. 

It  may  accordingly  be  said  that  the  polyvinyl  chloride  section 
of  the  British  plastics  industry  has.  to  a  large  extent,  lost  its 
enthusiasm  for  footwear  applications,  due  to  the  difficulties  of 
producing  exactly  the  right  kind  of  materials  and  adhesives, 
and  because  supplies  of  this  plastics  can  be  so  readily  sold  in 
more  remunerative  markets.  Added  to  this  is  the  fact  that  the 
footwear  industry  is  not  yet  convinced  that  vinyl  polymers  and 
copolymers  can  fill  their  specific  needs,  and  a  doubt  exists  as  to 
readiness  with  which  repairs  to  polyvinyl  chloride  soles  can  be 
made. 

Research  and  development  work  on  polyvinyl  chloride  for 
footwear  have  not,  however,  come  to  a  standstill  in  Britain,  but 
the  plastics  industry  does  not  now  regard  this  particular  ap- 


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plication  as  being  of  major  importance.  Until  such  time  as 
supplies  of  leather  and  rubber  are  released  from  controls,  there 
will  be  a  steady  tonnage  of  vinyl  polymers  used  for  soling, 
those  parts  of  uppers  which  are  subject  to  considerable  abrasion. 
and  ornamental  purposes  (such  as  tapes,  braids,  trimmings,  and 
others).  Polyvinyl  chloride  pastes  and  fibres  are  likely  to  be 
in  greater  demand  than  the  sheet  material. 

Multi-Color  Printing  Process  in  Scotland 

The  use  of  plastics  sheeting  for  shoe  uppers  makes  particularly 
interesting,  to  the  footwear  industry,  a  technique  newly  devel- 
oped in  Scotland,  for  multicolor  printing  of  plastics  sheeting. 
The  metluxl  is  described  by  manufacturers  in  the  plastics  field 
in  Britain  as  "a  major  achievement  in  the  printing  of  plastic-." 
Clifford  Carter,  textile  printer,  of  Paisley,  is  responsible  for  the 
development;  his  firm,  Artistic  Textile  Printers  Ltd.,  is  IMW 
going  into  increased  bulk  production  at  Kilmarnock. 

Previous  to  this  development,  three-color  printing  on  textile- 
was  regarded  in  Scotland  as  the  maximum,  and  register  and 
other  details  required  perfecting.  Although  it  was  known  that 
the  technique  of  multicolor  printing  had  been  perfected  by  Amer- 
ican technicians,  the  results  of  the  new  Scottish  process  are  said 
to  be  superior  in  artistic  presentation  to  the  products  which  have 
reached  Scotland  from  American  sources. 

The  method  employs  a  photographic  screen  and  airbrush,  hand- 
oi>erated,  which  permits  deposit  on  the  plastics  sheeting  of  pre- 
cisely the  amount  of  material  required,  so  that  flaking  of  the 
color,  or  harming  the  basic  material,  are  eliminated.  The  mate- 
rial most  favored  is  polyvinyl  chloride  sheeting,  but  any  fabric 
coated  with  this  resin  could  be  satisfactorily  handled;  the  process 
also  gives  excellent  results  on  nylon. 

The  company  is  working  as  commission  printers,  undertaking 
work  for  firms  having  suitable  materials,  and  a  great  demand  for 
its  services  has  been  evidenced  by  firms  prepared  to  adopt  this 
form  of  decoration  for  their  products.  An  index  to  possible  cost 
is  given  in  the  price  quoted  for  other  articles  produced ;  a  scarf, 
used  for  headcovering,  and  decorated  with  a  floral  or  other  motif, 
would  cost  21-  for  printing  alone.  Cost  of  a  decorated  tablecloth 
would  be  from  6/-  upwards,  depending  upon  the  amount  of  work 
involved.  It  is  claimed,  however,  that  the  cost  will  be  competi- 
tive with  that  of  any  other  hand-produced  decorative  effect. 


Additional  interesting  data  on  the  plastics  picture  in  Britain  is 
|.n--ented  in  an  account  by  Henry  \V.  HardiiiR.  who  has  recently 
returned  from  a  business  trip  through  England  and  France. 

Mr.  Harding,  president  of  the  Manufacturers'  Chemical  Corp. 
and  its  subsidiary,  Chemaco  Corp.,  Berkeley  Heidii-,  N.I. 
went  abroad  in  an  advisory  capacity  at  the  request  of  certain 
large  manufacturers  of  plastics  material  in  Britain,  as  well  as 
to  make  a  survey  of  the  new  developments  and  techniques  in 
the  industry-  He  reports  finding  optimism  generally  high  among 
British  molders  and  plastics  material  manufacturers,  although 
due  to  concentration  on  production  of  war  equipment  only,  during 
the  past  several  years,  some  aspects  of  progress  in  plastics  for 
civilian  consumption  were  necessarily  neglected.  Polystyrene,  he 
states,  is  in  very  limited  use  there,  and  cellulose  acetate,  acrylics 
ami  vinyls,  are  widely  used  but  not  in  great  volume,  their  cost 
varying  from  50%  to  300%  higher  than  cost  in  the  United  States. 

Extensive  projects  are  afoot  in  Britain,  says  Mr.  Harding,  to 
expand  production  of  the  basic  chemicals  for  plastic-  through 
the  formation  of  British- American  companies,  and  by  t! 
\uierican  production  methods. 

One  of  the  most  interesting  phases  of  the  British  pla-tic-  iii- 
.lustry  noted  by  Mr.  Harding  was  the  comprehensive  educational 
schemes  which  are  reaching  fruition  there  and  should  be  definitely 
e-tabli-lu-d  tlii-  year,  according  to  indication-.  \  omiprclien-ivc 
program  ot  this  sort,  launched  by  the  Institute  of  the  Plastics 
Industry,  is  designed  to  inform  both  the  manufacturer  and  the 
public  of  the  new  materials  in  the  "ever-expanding  plastics  fam- 
ily" ;  information  as  to  properties,  uses  and  limitations  of  plastics 
materials  is  supplied  through  this  program. 

The  Rritish  manufacturers  are  now  working  closely  with  sup- 
pliers of  raw  materials  to  expedite  developments  and  techniques 
in  plastics,  and  many  companies  have  allocated  substantial 
amounts  of  capital  for  new  laboratories  and  research  projects, 
while  several  contemplate  entering  American  markets 


94 


FHE  PLASTICS  INDUSTRY 

3y  Barrett  L  Crandall 

A  monograph  prepared  by  the  former  director  of  public  rela- 
tions, Society  of  the  Plastics  Industry,  this  is  one  of  a  series, 
inaugurated  by  the  publisher,  of  75  occupational  booklets,  each 
of  which  is  concerned,  separately,  with  a  basic  American  industry. 

Intended  for  use  in  connection  with  guidance  activities  wher- 
ever general  counseling  work  is  conducted,  and  for  individual 
reference  purposes  in  the  choice  of  a  career,  the  series  aims  to 
provide  not  only  an  over-all  picture  of  the  industry  treated  in 
its  pages,  but  also  specialized  information. 

Contained  in  the  pages  of  this  authoritatively  written  booklet 
are  'he  following  sections,  supplying  concise  and  comprehensive 
data:  (I)  The  Development  of  Plastics;  (II)  Make-up  of  the 
Plastics  Industry,  which  is  broken  down  into  sub-sections  on 
material  manufacturers,  molders,  fabricators,  and  laminators ; 
(III)  Forming  and  Fabricating  of  Plastics,  which  deals  with 
material  manufacturing  and  the  various  types  of  molding,  as  well 
as  fabricating  and  laminating;  (IV)  Sales;  (V)  Plastics  Ma- 
terials; (VI)  Personnel  in  the  Plastics  Industry;  and  sections 
VII  to  X  are  concerned  with  Wages,  Schools,  Trade  Asso- 
ciations, and  Trade  Papers,  while  section  XI  is  a  bibliography. 

A  feature  of  the  booklet  is  an  Analytical  Index  of  Occupations, 
which  has  been  especially  designed  to  assist  in  easily  locating 
nformation,  in  the  booklet,  on  the  type  of  employment  offered 
ly  the  plastics  industry.— Bellman  Publishing  Co.,  Inc.  Boston 
Mass.,  37  pages,  $1.00. 


Compression  Mold  Design 

(Continued  from  page  63) 


1 


the  piece   in  question.     These  pins  will   be  a  press   fit   in 
one  half  and  a  slide  tit  in  hardened  bushings  in  the  other. 

:  General  practice  presses  the  pins  in  the  top  half  so  that 

hey   extend  down  and   lead  the   punches   into  the   cavity. 

There  is  always  danger  that  flash  may  fall  into  the  bushing 

ioles   in  the  lower  half,  and  for  this  reason  these  should 
never  be  blind  holes,  as  an  accumulation  of  this  material 
will  eventually  cause  damage  to  pin  or  bushing.     For  this 
reason  the  hole  should  be  opened  to  the  outside  (Fig.  4) 
permit  escape  of  dirt  or  flash. 
Mash  also  tends  to  work   into  screw  heads  exposed  to 

he  parting  line  of  the  mold.     For  this  reason  screw  heads 

ihould  be  away  from  the  parting  line. 

Besides  the  standard  types  of  compression  molds  already 
discussed,  there  are  special  forms  used  to  meet  unusual 
problems  such  as  threads,  undercuts,  side  holes,  etc.  Threads 

ire  often  molded  on  plastics  pieces.     If  these  threads  are 
external,  they  can  be  molded  by  split  rings  (Fig.  5).     In 

his  case  the  splits  are  ejected  and  the  molding  is  removed. 

f  piece  design  is  such  as  to  permit  the  casting  being  un- 
screwed from  the  cavity,  the  thread  may  be  cut  into  the 

olid  cavity  and  the  molding  unscrewed  from  it  by  means 
of  electric  screw  drivers  or  other  devices.     On  this  type 
mold   the   half   containing   the   threads   is   often    pulled 

orward  out  of  the  press  to  permit  easier  access  for  un- 
screwing (Fig.  6). 

Internal  threads  are  usually  unscrewed.  Piece  design 
is  often  such  that  the  threads  are  on  the  punch  half,  which 


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ADDRESS 

CITY      .  STATE      . 


100-8    oi      Reed  -  Prentke    plailic 

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IN  centers  where  plastic  injection  molding  is  showing  exceptional  growth.  Reed -Prentice 
machines  keep  pace  with  the  expansion  of  the  industry.  Ready  acceptance  of  this  equipment 
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Outstanding  Rced-Prentice  leadership  is  due  to  such  machine  features  as  modern  design, 
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THE   WORLD'S    LARGEST    MANUFACTURERS    OF   INJECTION    MOLDING    MACHINES 


PLASTICS 


95 


PLASTICS 


PROBLEMS   AND    PROCESSES 


2nd  Mjilioa.  by    Miiup«rgcr  t>.    Pepper 

Tb.    h~*    cacm    railnlr    FABRICATION.    .1.0    orilln    >IK)    phr>lnl    rtur- 
•  rltrMIri     at     all     IJPM    l4     pUili.i      All     !.-.!>.     tqulpmrnl     and     luptilltl 
ilrxiliu-.l     W,  rklne    tilth    plaitln.    wood   «ml 
.1      >-.  rnilnK.    Muplnl  :    Kurfarlin  :    Flnl.hins: 
and    Marhlrw-W..rk    IT.J.I.mu.    Me. 
pUln.     r,l     llhi-  i.-ilcni.    rluth. 

an.!  manufarturrr- 


ry    »r«    Illiulratn)    an. 
•Mil    rtplaliwtl    ant    llluiin 

tot    P..O.    ««•.    «1    pcutl. 
TtiU  book   1.   r.> 


HONEY  BACK  GUARANTEE.  01, 


S3.  SO  KMt  mid. 


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ADOBE** 

CITY 


PLASTIC  EXTRUDERS  WANTED 

Sizes  2*/2  inch  diameter  screw  and 
larger,  with  either  cross-head  or  straight- 
head  accessories. 

Write  BOX  115,  e/o  PLASTICS 
185  N.  Wabash  Ave.,  Chicago  1,  Illinois 


INJECTION    MOLDING 

Speelaliits  on  short  production  Jobs  and  experimental  work. 
Open  Capacity  at  present. 

Alto 
Compression   Molding — Plastic  Fabricating. 


PLASTIC  PRODUCTS  CO. 


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Wycboff  St.         Brooklyn.  N.  Y.         MAm  5-182? 

ANDREW    C.    KARLSTAD 

INDUSTRIAL  DESIGNER 

COMPLETE    PRODUCT    DESIGN   &   ENGINEERING    SERVICE 


4144  VENTURA  CANYON  AVE. 
PHONE— STATE  • 


SHERMAN  OAKS.  CALIF. 
(A  SUIURI  OF  LOS  ANGELES) 


ROUTER  BITS— FORM  CUTTERS  and 
MACHINES  for  HIGH  SPEED  CON- 
TOUR and  STRAIGHT  CUTTING  PLASTICS 

5»««f  lot  C  ailot  No,  41 

EKSTROM,  CARLSON  &  CO. 

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AUSTIN  TOOL  &  MFG.  CO. 

1859  E.  63rd  STREET       -:-       CLEVELAND  3.  OHIO 

EXpr««   1000 

PLASTIC  MOLDS  iinioas 

(?»OT<1«OBS   Wl'tMl   41 


can  be  slid  out  and  tipped  to  a  vertical  position  for  UIIM.-I  ow- 
ing. On  molds  where  the  piece  is  unscrewed,  no  knock- 
out pins  are  necessary.  On  certain  jobs  such  a-  bottle 
caps,  a  round  glass  container  thread  is  used.  This  thread 
may  be  so  designed  that  moldings  need  not  be  unset 
but  can  be  forced  off  the  punch  by  use  of  a  stripper  platej 
This  saves  considerable  time  in  the  operation  of  such  molds. 

Pieces  which  will  not  draw  from  the  usual  type  mold 
because  of  undercuts  or  side  bosses  are  molded  in  what 
are  known  as  split  molds  (Fig.  7).  Here  the  split>  are 
ejected,  pried  apart,  and  the  molding  is  removed.  'I 'hose 
splits  may  be  half-round  pieces  fitting  into  a  round  tain-red 
hole  in  the  chase,  or  they  may  be  rectangular  wedges  fitting 
into  tapered  grooves  milled  into  the  chase. 

There  are  many  other  special  problems  of  cavity  desigl 
to  produce  unusual  parts.  To  cover  these  thoroughly  would 
be  beyond  the  scope  of  this  article.  In  most  case- 
piece  is  a  problem  to  be  solved  by  the  ingenuity  and  exi*-ri- 
ence  of  the  designer,  but  in  all  cases  this  ingenuity  must 
be  backed  by  a  thorough  understanding  of  the  fundament* 
principles  of  mold  design  and  molding  technique.  i  NU 


Edgelighting  Murals 

(Continued  from  page  30) 


murals  is  an  excellent  example  of  integration  between  .1  de- 
signer's ideas  and  a  fabricator's  methods.   Mrs.  Mary  Morri 
son  Kennedy,  consulting  director  of  the  Sheraton   llnti 
chain,  was  responsible  for  the  general  subject  matte > 
of  the  shadow  boxes,  and  for  the  amount  and  intensity  06 
color.  Artists  of  the  Endicott  Corporation  designed  and  cxeH 
cuted  each  panel. 

After  an  initial  agreement  on  design  and  size,  -kctc 
were  submitted  on  black  paper,  with  white  lines  to  indi 
the  engraving  and  shading  effect.    Color  was  applied 
these  drawings  in  order  to  show  the  general  theme  prior 
engraving  the  Plexiglas.  A  model  of  a  shadow  box  \\ 
graved,  painted,  and  shown  for  approval.   At  this  time,  t" 
light  source  was  decided  upon  in  accordance  with  the  d 
mauds  of  each  drawing  and  subject.  Since  light  governs 
intensity  and  effect  of  the  mural,  the  light  source  was 
primary  importance.    Fluorescent  tubes  were  used  U-ca 
of  their  evenness  of  illumination  and  low  heat  output.   I.i 
ing  arrangements,  as  well  as  shadow  box  construction,  \v< 
engineered  by  the  Endicott  company. 

These  murals  are  illustrative  of  only  one  of  many 
sible  applications  for  edge-lighting.   I'nder  the  direction 
Henry  F.  Pearson,  the  Product  Design  laboratory  of  Ron 
&  Haas  Company  has  evolved  various  edge-lighting  effi 
Mr.  Pear-oil  was  primarily  responsible  for  the  develo 
of  three-dimensional  murals  and  radiant  walls,  and  In- 
enlarged  the  application  of  this  edge-lighting  principle 
interior  decoration  and  architecture.    At  the  opening  of  t 
Sheraton  Lounge,  he  showed  some  of  its  |mssihilities. 

For  example,  some  of  the  engraving  can  IK-  placed 
front  and  back  of  all  except  the  top  sheet.    The  back  surf, 
of  each  -heel  reflects  more  light,  but  the  reduced  brillia: 
of  front-surface  reflection  may  be  useful  in  certain  <1< 
Paint  and  engraving  may  U-  combined  for  still  further 
lication  of  the  result.    The  distant-.-  lietween  the  sheets 
be  varied,  or  each  sheet  may  IK-  of  a  different  thickness, 
some  cases,  according  to  Mr.  I'e.ii-on.  the  designer  may  li 
it   de-irable   to  cut   out    section-   from   one  or   more   of  t 
-beet-.     If  color   i-  added  to  the  edge  tbn-   formed,  light 
plea-ing  tint  can  IK-  thrown  on  some  other  part  of  the  de-i 

Tin-  color  of  a  |>ainted  -virface  al-o  In-ar-  a  relation-hip 
the  light  tran-mis-ion  from  the  /'/i'.nV//iJ.t  sheet.    When  li; 
-trike-  a  painted  design.  Mime  of  it  is  ab-orU-d.  -omc  esca 
from  tin-  -beet  and  raii-e-  the  design  to  glow,  and  tin- 
continue-  to  navel  within  the  plastics.    If  too  much  light 

NOVEMBER  1916J 


absorbed  by  the  paint,  there  will  be  a  decrease  in  the  light 
intensity  of  the  design.  Paint  applied  to  a  panel  should  there- 
fore be  fairly  light  in  color  and  should  not  occupy  too  great 
a  proportion  of  the  surface. 

Some  sort  of  backing  for  an  edge-lighted  panel  is  often 
desired.  It  need  consist  of  nothing  more  than  a  single  sheet 
of  paper  or  other  opaque  material,  and  any  color  or  design 
may  be  chosen.  Such  a  background,  being  unattached  to 
the  sheet,  remains  unlighted  when  a  design  is  illuminated. 

Here  again,  the  originality  of  the  designer  can  be  used 
to  produce  almost  endless  variations  in  the  effect.  By  hav- 
ing the  background  color  match  that  of  the  design  painted 
311  the  plastics,  the  pattern  can  be  made  to  appear  or  disap- 
pear as  the  light  is  turned  on  or  off.  . 

In  engraving  or  painting  a  Plexiglas  sheet,  the  entire 
surface  cannot  be  covered  and  still  be  edge-lighted  satis- 
factorily. The  design  must  be  intermittent,  to  allow  reflec- 
:ion  of  the  light  back  and  forth  between  the  surfaces,  other- 
wise it  is  largely  diffused  from  the  sheet  through  the  portion 
)f  the  design  nearest  the  source. 

One  of  the  difficulties  in  edge-lighting  designs  is  in  provid- 
ng  sufficient  illumination  over  a  large  area.  There  is  no 
single  solution  to  this  problem.  Although  each  separate  case 
•equires  individual  handling,  there  are  some  considerations 
.vhich  may  be  applied  effectively  in  many  instances.  The 
:hickness  of  the  material  is  of  primary  importance  since  the 
vider  the  edge,  the  greater  the  quantity  of  light  entering. 

The  character  of  the  edge  through  which  the  light  enters 
:he  Plexiglas  sheet  is  also  important.  It  should  be  polished, 
ind  be  at  right  angles  with  the  sheet  surface.  A  rough, 
)eveled,  or  wavy  surface  will  transmit  light  into  the  ma- 
:erial  at  angles,  some  of  which  will  permit  it  to  escape  im- 
nediately. 

The  light  source  is  of  primary  importance  in  edge-lighting, 
experiments  have  shown  that  the  ideal  source  is  a  line 
ilament  lamp,  with  the  edge  of  the  plastics  as  close  to  the 
ight  source  as  possible.  In  practical  application,  however, 
ise  of  a  filament  source  of  this  type  meets  with  objection 
>ecause  of  the  heat  developed.  Moreover,  line  filament  lamps 
ire  not  readily  available  in  the  lengths  required  for  many 
.pplications.  Because  of  these  limitations,  line  filament 
amps  have  been  generally  replaced  with  fluorescent  tubes, 
vhich  produce  a  lower  intensity  of  illumination,  since  only 

comparatively  small  amount  of  light  from  a  tube  can  be 
[irected  into  the  edge  of  the  Plexiglas.  The  tubes  are  also 
iractically  free  from  heat  and  are  available  in  satisfactory 
engths. 

When  more  intense  light  is  desired  and  fluorescent  tubes 
ire  not  practical,  special  methods  of  lighting  with  hot  fila- 
nent  lamps  may  be  devised.  Line  filament  lamps  could  be 
ised  by  separating  the  Plexiglas  from  the  tube  with  a  piece 
"  tempered  glass.  The  lamps  should  be  placed  at  a  focus 
a  metallic  reflector,  having  a  radius  of  about  one-third 
nore  than  that  of  the  tube.  This  reflector  should  be  brought 
ip  around  the  tube,  completely  enclosing  it  except  for  a  deep 
lot  at  the  top.  A  piece  of  tempered  glass,  placed  in  this 
.lot  in  contact  with  the  tube,  provides  the  base  on  which 
he  Plexiglas  rests.  This  arrangement  secures  most  of  the 
ighting  value  of  the  line  filament  lamp  without  exposing 
he  plastics  to  undue  heat  hazard. 

While  edge-lighting  opens  a  wide  field  for  decorative  and 
irchitectural  uses,  there  are  certain  limitations  on  its  ap- 
)lication.  Obviously,  dirt  and  scratches  on  the  acrylic  ma- 
erial  disturb  the  surface  as  do  paint  or  engraving,  and  pro- 
luce  defacement  which  will  be  edge-lighted  with  the  design. 
iVhen  edge-lighting  is  used  where  the  plastics  is  exposed  to 
;onsiderable  scratching  or  soiling,  it  is  sometimes  desirable 
o  cover  the  panels  with  a  protective  sheet  of  glass. 

Plexiglas  and  the  edge-lighting  principle  lend  themselves 
test  to  basic  clear  colors  with  simplicity  of  design.  In  de- 
igning Plexiglas  murals,  the  most  satisfactory  effects  are 
trained  with  few  lines,  and  an  "open"  technique.  END 


One  of  a  leriej  covering  Wonders  of 
(he  World.  Con  you  name  some  of 
the  others?  Watch  NOICO'J  next  ad. 


THE  Hanging  Gardens  of  Babylon,  built  over 
2500  years  ago,  were  an  outstanding  archi- 
tectural achievement.  This  'Wonder'  is  probably 
one  of  the  best  remembered.  Nosco  has  achieved 
remarkable  results  by  properly  designing  and 
engineering  plastic  products.  If  you  are  now 
using  or  contemplating  the  use  of  plastics,  write 
Nosco  where  Ingenuity  is  For  Sale. 


NOSCO 


o  I  v  f  s  i  o  H     or 

i  *  T  i  o  N  A  L    o  a  o  *  M    urn*   to 


'.  «t  >  I      PA 


For  PANTOGRAPHIG  ENGRAVING 

ON  PLASTICS 


for 


Panto     Engravers, 

rugged  and  precision-built, 
accurate  and  clean-cut 
engraving  on  plastic 
and  metal  products. 
Depth    Regulator. 
available    with    all 
models,   produces  a 
uniform  depth  of  engraving 
on    irregular    and    curved 
surfaces.     Forming    Guide. 
on  the  UE-3  only,  for  use 

Model  UE-3.  on  curved,   spherical,   and 

Also  lighter  60  beveled  surfaces. 

models  UE,  UE-2. 

Engraving  cutters,  master  copy  type,  fixtures,  and  end- 
less round  belts,  for  all  types  of  engraving,  die  and 
mold-cutting  machines. 


MODEL    CG    GRINDER 

for  quick  and  accurate 
sharpening  of  engraving 
and  routing  cutters. 

»  Catalog 
on  request 


H.  P.  PREIS  ENGRAVING  MACHINE  COMPANY 
151E  SUMMIT  STREET  NEWARK  4,  NEW  JERSEY 


PANTO  MARKING  EQUIPMENT 


I'LASTtCS 


97 


Accurate  Spring  Manufacturing  Ce. 
T.  Gray,  lac. 


American  Photocopy  Equipment  Co. 
Arthur  MeyerhoU  4  Company 

Amos  Molded  Plastics 

Sidener  and  Van  Riper.  Inc 

Arrow  Plastics,  Inc. 

Power  ad  Company,  The 

Auburn  Button  Works.  Inc. 
Charles  I.  RumriU  4  Company 

Austin  Tool  &  Mia.  Co. 


41 
14 

65 
96 


Bamberger,  A. 

H.  W.  Fairfax  Advertising  Agency 


Kaisd.il  Pencil  Co. 

Richard  A.  Folty  Advertising  Agency 

Boice-Crane  Company 

Wendl  Advertising  Agency 

Boonlon  Molding  Company 
The  Franklin  Fader  Company 

Brilhait.  Arnold.  Ltd. 

Henri  Le  Nolhe  Agency 


n 

•3 
99 
36 
Back  Cover 

76 

89 


Cee-Bee  Mia.  Company.  The 

Cello-Plastic  Chemical  Co. 
The  McCarry  Company 

Celluplastic  Corporation 
M.  C.  Dirdrich  Advertising 

Chemaco  Corporation 

R    T.  O'Connell  Company 

Consolidated  Molded  Products  Corporation 
Waller  I.  Gallagher  Advertising 

Continental  Plastics  Corporation 
lira  Cutty  Company 

Cumberland  Engineering  Co. 

Richard  Tborndike  Precision  Advg. 


Dale  VentO  Sole,  Inc. 
Brad-Vern,  Van  Diver  4  Carlyle 

Defiance  Machine  Works.  Inc. 
Beeson.folJer  Reichert.  Inc. 

Duall  Molding  Corporation 
Gann-Mears  Advertising  Agency 


,  Carlson  &  Co. 

Cnmmings-Brand  4  McPherson.  Advg. 

Famco  Machine  Co. 

Western  Advertising  Agency 

General  Chemical  Company 
Afherton  6  Currier,  lac. 

General  Electric  Company 
Benlon  4  Bowles.  Inc. 


45 
75 
100 

95 
10 
96 

96 
92 

29 
8 


Gerinq  Products.  Inc. 
M.  C    Diedrich  Advertising  S3 

Girdler  Corporation,  The 
Roche,  Williams  4  Cleary,  lac.  5 

Goodrich.  B.  F  .  Chemical  Co. 
GriswoJd-Eshleman  Co..  The      Second  Cover 

Grays  Harbor  Industries.  Inc. 
Frederick  E.  Baker  and  Associates 

Great  American  Color  Company 
Bodine  4  Meiuner  Advertising 

Grigoleit  Company.  The 

Mace  Advertising  Agency,  Inc. 

Hydraulic  Press  Mfg.  Co.,  The 
lay  H.  Maish  Company,  The. . 

Industrial  Equipment  Company 
Louis  F.  Herman  Advertising  Agency 

Interlace  Chemical  Corporation 
Stanley  POaum  Associates 

International  Plastic  Harmonica  Corp. 
Marcel  Schulhoti  4  Company 

Karlstad,  Andrew  C 

Kingsley  Gold  Stamping  Machine  Co. 
Continental  Advertising  Service 

Kirk.  F.  J.,  Molding  Co. 

Cory  Snow,  Inc 


91 


.93 


67 


94 


27 


47 


96 


86 


84 


Krieger  Color  S  Chemical  Co. 
Warren  P.  Fehlman  Agency 

Kuhn  6  Jacob  Molding  &  Tool  Company 
Eldridge-Northrop.  Inc 

Kurz-Kasch.  Inc. 

Kircher.  Helton  4  Collet! 

Leach.  H..  Machinery  Co. 
Joseph  Maxlield  Company 

Maas  &  Waldstein  Company 
Doyle.  Kitchen  4  McCormick.  Inc. 

Magnetic  Plastics  Co.,  The 

Gregory  House  Advertising.  Inc. 

Midland  Die  4  Engraving  Co. 
Behel  4  Waldie  4  Briggs 

Missouri.  The  State  of 
Poffs-Turnbuii  Co 

Modern  Technical  Book  Company 

Mosinee  Paper  Mills  Company 

Kiau-Van  Pieterson-Dunfap  Associates.  Inc. 

National  Lock  Company 
L    W.  Ramsey  Company 

National  Organ  Supply  Co. 
P.  W.  Price.  Advertising 

National  Plastic  Products  Co.. 

The  Joseph  A.  Wilner  Company 


94 


13 


79 


61 

85 
96 


National  Vulcanised  Fibre  Co. 
Joan  Gilbert  Craig  Advertising 31 

New  Jersey  Sprayed  Products  Co..  Inc.  87 

Oxley,  John  H..  Company 
Allied  Advertising  Agency  92 

Park  wood  Corporation 
Cory  Snow,  inc.    .  .  .  77 

Plaskon  Division,  Libber-Owens-Ford  Glass 

Company 
Mekfrum   4  Fewsmilh  35 

Plastics  Machinery  72 

Plastic  Products  Co. 
A.  F.  Ligotti  Advertising  96 

Plastic  Service  Engineering 90 

Preis.  H.  P.,  Engraving  Machine  Company 
W.  O.  Nettleton  4  Associates  97 

Presque  Isle  Plastics,  Inc.  68 

Printloid.  Inc. 
Reiss  Advertising    .... 


Radio  Receptor  Company,  Inc. 

O.  S.  Tyson  4  Company,  Inc 

Rayon  Processing  Co.  of  R.  I..  Inc. 
Richard  Thorndike  Precision  Advg.        83.  34 

Reed-Prentice  Corporation 
Howard  Wesson  Company 

Rohm  &  Haas  Company 
Newell-Emmeft  Company    . 

Schwartz  Chemical  Co. 

Walter  W.  Wiley  Advertising,  Inc. 

Sieqel.  M.  B..  Associates 

Craig  E.  Dennison  Advertising  Agency 

Sossner 
Ehrlich  4  Neuwirth 

Stokes.  F.  I.,  Machine  Company 
McLain  Organisation.  Inc. 

Tennessee  Eastman  Corporation 
Kenyan  4  Eckhardl.  Inc 

Van  Dorn  Iron  Works  Co..  The 
Hubbell  Advertising  Agency.  The 


Watertown   Manufacturing  Company,  The 
R.  T.  O'Connell  Company 


Worcester  Moulded  Plastics  Co. 
C.  Jerry  Spaulding,  Inc. 


57 
Third  Cover 


IF  YOU  WANT  OUTLETS 
CONTACT  US 

Anything    pertaining    to    Smoker*    Articles 

or    General    Merchandising    and    Novelties 


We  Contact  Jobbers  and  Chain  Store  and 
Department  Stores  from  Coast  to  Coast! 


(IT.  VIII  Cmrrj  Our  Own  /fecvunu  (/ 
*      *      * 

M.  B.  SIEGEL 

ASSOCIATfS 
•  ACTOIV   IIPIISSNTATIVII   AND   DIJT1I8UTOBS 

63  E.  ADAMS  ST.  CHICAGO  3.  ILL 


81 

Wrigley,  Wm..  Jr..  Company 
Rulhraufl  4  Ryan.  Inc. 

73 

97 

o..  The 
Hnpany 

86 

Yardley  Plastics  Co. 
Byer  4  Bowman  Advertising  Agency 

59 

CLASSIFIED  ADVERTISING 


KIK  SALE:     Injection  Moulding  Machln.' 

Its*  thsn  s  year  old.    M»y  be  seen  In  operation 

Inc.,  «  Water  St..  Attlcboro.  Mass. 


.  II  !•  M      l.alcil  mod*),  j 
Standard  Plastics  Co.J 


METALLIZING  on  plastics  of  all  types  and  glassware,  perfume  tmtile 
dlshev    Outstanding  eipert  with  many  Tears'  practical  eiperiencejle«iln 

"'.  Wabash  ." 


•M  connection.    Bo*  118.  %  Plastic*.  185  N. 


i  Are  .  Chlcav 


FOR  HALE:     Dayton  Air  Compressor  *5  K-S1.    Two  stage  7H  HP    thr*«J 
phsw  «0  cycle.  «0  roll  AC  motor.     Mounted  on  80  gallon  AKMK  tank. 
Magnetic  Starter  anrt  s  ......  .mtrol     New—  Tncrsted  -Immediate  DellTery.] 

Sydney  -Thomas  Corp..  1351  Ferguson  Rosd,  Cincinnati  5.  Ohio. 

PLART1C  EXTRUDING.  Oezlble  or  rigid,  open  capacity  for  all  ex 
tubing.  rod«,  channel!  and  belling     We  «uppl;  all  materlal—yonr  Inquiry 
Intlted     Auorlated  Machinery  *  Products  Co  .  60  Branford  Plac. 
arl>.   N    J  _ 

_  SITUATIONS    WANTED  _  _ 

i   MKMKM.S      IU«     materials      Import    purrhaslng  —  export        Top    Mm    of 


world-known  Houae,  over  5  Team  In  prenent  employ.  41   yra.. 
ilepemlable.   wlihe<<  to   Join  ethics),    aggrenilre.   financially   strong  organl 
/•lion      Hoi    11  ••    '.    l'l«Mli'«.   l»r>  N     W.ila.h   Are  .  Otllcagn  1.   Ill 


Fight  TUBERCULOSIS 
BUY  Christmas  Seals 


N 


f» I.  A  S \T 1 1  '9t 


NOVKMBKR 


Statistical  Data 


JULY  shipments  and  consumption  of  66,160,824  Ib  of  plastics 
and  synthetic  resins  as  reported  by  the  Bureau  of  the  Cen- 
sus, reveal  a  gain  of  approximately  10%  over  the  June  total  of 
59,323,484  Ib. 

Gains  were  evident  in  every  category  except  the  phenolic  and 
other  tar  acid  laminating  resins  and  the  cellulose  acetate  and 
mixed  ester  continuous  sheets  of  .003  gauge  and  upward.  The  phe- 
nolics  and  other  tar  acid  resins  employed  in  laminating,  adhe- 
sives,  and  in  molding  materials  with  a  total  of  22,705,714  Ib 
constitute  l/j  of  the  total  consumed.  The  vinyl  resins,  in  all  forms 
and  applications,  are  next  with  12,096,229  Ib;  followed  by  cellu- 
lose acetate  and  mixed  ester  plastics,  9,050,081  Ib ;  polystyrene, 
5,746,830  Ib;  urea  and  melamine,  4,938,983  Ib;  nitrocellulose 
plastics,  1,523,777  Ib;  and  miscellaneous  plastics  and  resins,  10,- 
099,210  Ib. 

Gains  in  Consumption 

The  molding  and  extrusion  processes  used  about  38,000,000  Ib 
representing  50%  of  the  total,  the  balance  distributed  in  lam- 
inating, adhesives,  textile  and  paper  treating  and  in  other  mis- 
cellaneous uses.  The  urea  and  melamine  resins,  with  an  increase 
over  June  of  25%  and  the  vinyls  with  a  rise  of  13%  showed 
their  heaviest  gains  in  the  use  of  resins  for  treating  and  coating 
textiles  and  paper.  Polystyrene  continues  to  show  a  substan- 
tial increase  from  month  to  month. 

The  statistics  below  represent  the  shipments  and  consumption 
of  plastics  and  synthetic  resins  as  reported  by  77  manufacturing 
companies  and  company  departments.  Data  for  synthetic  resins 
for  protective  coatings  are  not  included.  Shipments  include  data 
for  plastics  and  resins  manufactured  by  the  reporting  companies 
or  company  divisions  and  shipped  to  outside  users.  Consumption 
refers  to  the  plastics  and  resins  manufactured  and  used  by  the 
reporting  companies  and  company  divisions. 


Plastics  and  Synthetic  Resins  Shipments 
and  Consumption  (Ib) 


Item 


July 
1946 


June 
1946 


Cellulose    acetate    and    mixed    ester    plastics' 
Sheets 

Continuous  (under  .003  gauge) 770,495  690,01 1 

Continuous  (.003  gauge  and  upward.  .  .  .  687,416  751,572 

All  other  sheets,  rods  and  tubes 425,370  384,765 

Molding  and  extrusion  materials 7,166,800  *6,735,990 

Nitrocellulose  plastics' 

Sheets 921,163  864,420 

Rods  and  tubes 602,614  564,629 

Phenolic  and  other  tar  acid  resins 

Laminating  (dry  basis) 2,338,486  2,573,412 

Adhesives  (dry  basis) 1,199,637  996,569 

Molding  materials' 14,190,536  14,161,634 

All  other  (dry  basis)' 4,977,055  4,818,844 

Urea  and  melamine  resins 

Adhesives  (dry  basis) 3,371,475  2,596,207 

Textile  and  paper  treating  (dry  basis) 1,303,859  886,620 

All  other  (dry  basis)2 263,649  145,115 

Polystyrene1 5,746,830  5,639,484 

Vinyl  resins 

Sheeting  and  film' 2,107,886  1,857,160 

Textile  and  paper  coating  resins  (resin  content)  1,624,203  1,234,522 

Molding  and  extrusion  materials  (resin  content)  5,398,1  94  4,978,168 

Adhesives  (resin  content)' \  „ 

All  other  (resin  content)2 /  "2,965,946  '2,402,566 

Miscellaneous  plastics  and  resins 

Molding  and  extrusion  materials',  3 6,403,457  4,850,236 

All  other  (dry  basis)2,  « 3,695,753  2,191,560 


TOTAL 66,1  60,824      59,323,484 


*  Revised.   'Includes   fill 
Coating  resins. 


Fillers,   plastlcizers   and    extenders.  2Excludes   data   for   protective 

Coating  resins.  ^Cannot  be  shown  separately  without  disclosing  operations  of  individual 
establishments.  -"Proportion  of  estimate,  2.9%  or  less.  ^Includes  data  for  ethyl  cellulose, 
urea  and  melamine,  acrylic  acid  and  miscellaneous  molding  and  extrusion  materials. 
6lncludes  data  for  petroleum  resins,  acrylic  acid,  ester  resins,  mixtures  and  miscellaneous 
jynthetic  materials. 


The  Ideal  Power  Tools 
for  the  Plastic  Industry 


Boice-Crane  Drill  Presses  in  use  at  General  Industries,  Elyria,  Ohio 

Boice-Crane  Power  Tools  have  been  designed  for  ready  adapt- 
ability to  a  wide  range  of  projects.  Thus,  fewer  machines  are 
needed  to  meet  all  your  requirements. 

Sturdily  built,  production  proved,  and  safety-engineered, 
Boice-Crane  tools  are  available  for  scores  of  machining  and 
finishing  operations.  There  are  band  saws  and  jig  saws  for 
straight  and  contour  cutting,  and  equipment  for  drilling,  rout- 
ing, tapping,  shaping,  surface  and  end  grinding  (removing 
flash),  surfacing,  polishing,  etc. 

k/f/7e  for  free  48-page  catalog. 

BOICE-CRANE   COMPANY 

972  Central  Avenue        •  Toledo  6,  Ohio 


Drill  Presses 
Belt  Sanders 
Spindle  Sanders 


Jig  Saws 
Band  Saws 
Jointers 


Lathes 

Spindle  Shapers 
Thickness  Planers 


INJECTION 
MOLDING 


OW  PLASTICS  INC.       PASSA1C.  N.  J 


NOVEMBER  1946 


PLASTICS 


PROBLEMS 


in  plastics 


Problems  and  questions  may  be  submitted 
to  thii  department  for  answering  by  the  tech- 
nical editors  or  specialists  in  the  industry. 

We  are  interested  in  replacing  the  glass  shields  used  in  fluor- 
<--i-< -in  tubing  with  a  lightweight  plastics.  Cost  is  no  considera- 
tion. What  plastics  material  do  you  suggest  as  being  suitable 
for  this  purpose?  /  I.  M..  Wilmette,  III. 

.  I  ri</irf  vinyl  or  an  acrylic  would  be  satisfactory. 

*  *     * 

We  have  just  been  able  to  purchase  a  large  quantity  lot  of 
rigid  "vinyl  scrap  which  we  plan  to  use  in  the  manufacture  of 
several  of  our  novelty  products.  However,  we  are  wondering 
if  this  material  could  also  be  used  in  the  production  of  our  lamp- 
shades, which  we  have  heretofore  satisfactorily  made  of  cellulose 
acetate.  J.  E.,  San  Francisco,  Calif. 

(I'r  i»-r>nM  not  adinse  that  you  use  rigid  innyl  for 
lampshades.  The  normal  heat  produced  by  an  electric 
bulb  icould  distort  this  plastics  material. 

*  *     * 

As  manufacturers  of  shampoos  and  other  hair  lotions,  we  arc 
desirous  of  having  a  container  made  for  our  products  which  will 


be  both  lightweight  and  unbreakable.  Is  there  a  plastics  material 
which,  in  addition  to  having  these  characteristics,  will  n-sii-t  the 
volatile  oils  and  the  alcohol  contained  in  our  produ. 

E.  B.  Y.,  Highland  Park,  X.  J. 
Polyethylene  would  best  fit  your  requirements. 

*  *     * 

What  is  the  coating  which  is  put  on  plastics  beads  to  make 
them  simulate  pearls:  H.  B.  F.,  Houston,  i 

This  is  a  "pearl  essence"  which  is  made  up  of  herring 
scales,  which  are  purified  and  incorporated  in  a  viscous 
plastics  base. 

*  *    * 

In  metal  plating  of  plastics,  what  is  the  purpose  of  sand-blast- 
ing the  plastics?  J.  S.,  Tucson.   Ari/ 

This  is  done  to  remove  the  natural  gloss  of  the  plastics 
so  that  there  is  better  adhesion  between  it  and  the  metal. 
Small  plastics  parts  can  be  tumbled  to  accomplish  this, 
but  larger  parts  must  be  sand-blasted. 

*  *     * 

I  have  been  experimenting  with  acetate  film  in  the  preserva- 
tion of  documents,  but  have  had  occasional  trouble  with  the  film 
adhering  to  the  surface  of  the  press.    Can  you  give  me  a  i 
for  this?  M.  D.  K.,  Tampa.  Fla 

You  may  be  using  a  film  U'hich  is  more  highly  plasti- 
cized  than  regular  sheet  stock  cut  from  blocks.  In  this 
case,  you  would  be  likely  to  encounter  sticking. 

*  «    * 


In  injection  molding  an  acetate  piece,  we  incur  an 
amount  of  sticking  in  the  die.    Can  you  offer  a  solution  to  this 
difficulty?  M.  B.  F..  NYw  York.  X.  V. 

Various  factors  should  be  considered  in  attemptinn 
to  solve  your  problem.  The  die  itself  may  be  at  fault 
line  l<>  undercuts,  damaged  surface,  or  an  incorrectly 
designed  knockout.  You  may  be  using  a  poor  lubri- 
cant. the  material  may  be  too  soft  and  you  may  be 
holding  pressures  too  loini.  thereby  preventing  the 
usual  amount  of  shrinkaiie. 


Expressly  designed  for 
granulating  the  various 
types  of  plastic  materials 

Advanced  design  features  enable 
Cumberland  machines  to  perform  at 
maximum  efficiency  the  special  cut- 
ting required  by  plastics  materials. 
Machines  are  made  in  two  styles: 
smaller  machines.  No.  0,  No.  l/i  and 
No.  1  '/2  as  at  right  (No.  Vt  illustrated). 
Style  of  large  machines  as  at  left 
with  retractable  knife 
block  for  maximum 
accessibility  (18"  Ma- 
chine illustrated). 

Request  illustrated 
CATALOG  NO.  200 

CUMBERLAND  ENGINEERING  CO. 

Oep  '.  t     Eex  216,  PrevMente,  R.  I. 


100 


rrlnt»«l  in  ' 

PI.  AST  14 


N0\  KMHKR    1946 


INSTEAD  OF  HP  TAKE  WMP 

•  HEADACHE  POWDER 


Costly  reinspection,  the  headache  and  liability 
to  so  many  production  schedules,  is  eliminated 
completely  at  the  source  and  never  plagues  a 
Worcester  Moulded  customer.  As  Custom  Injection 
Moulders  exclusively,  we  inspect  every  unit,  just 
as  thoroughly  as  if  the  product  were  our  own. 
Employees  are  trained  in  every  fundamental  of 
inspection  —  visualizing,  detection  of  flaws  in 
material  and  finish,  checking  precision  tolerances. 
When  they  reach  you,  your  parts  or  products 
are  letter  perfect.  For  a  happy  ending  to  pro- 
duction problems  in  plastics,  you'll  find  it  pays 
to  start  with  Worcester  Moulded  Plastics,  the 
largest  firm  of  its  kind  in  the  East. 


(gwdtiMn  Jriuecti&n  v/ttoatavrui 

WORCESTER  MOULDED  PLASTICS  CO. 

14  HYGEIA  STREET,  WORCESTER  8,  MASS. 

17   East  42nd  St.,   New   York   17,  N.  Y. 
130  West  Chippewa   St.,   Buffalo   2,  N.   Y. 


The  aboW  key  set  handles  are 
molded  of  Celanese  Celcon  for  Stand- 
ard Pressed  Steel  Co.  of  Jenkintown.  Pa. 

These  unusual  kits  are  proving 
extremely  popular. 


in  compression,  injection,  transfer 
molding  and  precision   machining. 


ARNOLD  BRILHART  LTD. 


Middl«n<?ck  Rd.  Great  Ncck.N.V.  n»*e-.  Great-  Neck  40  54 


EC  EMBER 
1946 


m 


VW 


.- 


Now  they're  making 
highway  markers  from  GEON 


Another  interesting  application  for 
GEON  raw  materials 

THOSE  highway  markers— mure  properly  known  as 
"traffic  paint  protectors"— are  lightweight,  easy  to 
handle.  They're  permanently  colored,  unaffected  by  sun, 
rain,  air,  heat,  cold,  paint,  oil,  or  any  one  of  hundreds 
of  normally  destructive  factors.  They're  sufficiently 
resilient  that  they  won't  break  when  dropped  from 
truck  to  painted  line.  Nor  will  they  harm  a  tire  if  acci- 
dentally struck  by  a  car.  It  was  possible 
to  mold  them  from  one  of  the  GEON 
polyvinyl  materials  in  such  a  way  that 
they  .stack  easily,  yet  always  land  in  the 
right  position  when  dropped  from  the 
paint  truck. 

These  properties,  plus  many  others. 


have  made  versatile  GEON  the  ideal  material  for  liter- 
ally hundreds  of  products  in  the  home  and  in  industry 
—shower  curtains  and  fly  swatters— upholstery  and 
floor  tiles— clothing  and  luggage— wire  insulation  and 
acid  tank  linings. 

And  GEON  can  be  pressure  or  injection  molded,  i-x- 
truded,  calendered  or  cast  into  sheet  or  film.  In  solu- 
tion or  latex  forms  it  can  be  applied  as  coatings  for 
fabrics  and  fibres  of  all  kinds  as  well  as  for  paper  and 
cardboard.  Products  made  from  GEON  may  he  flexible 

or  rigid,  clear  or  opaque,  brilliantly  or 

delicately  colored. 

I  <>r  more  information  about 
GEON,  please  write  Dept.  U-12.  B. 
F.  Goodrich  Chemical  (.'omp.mv. 
Rnxi-  l!u:  Mini;.  Cleveland  15,  Ohio. 
In  (  .in. nl. i:  Km  lu  MIT.  Ontario. 


B.  F.  Goodrich  Chemical  Company 


A  DIVISION  O» 
TMt  B  f  GOOO'":- 


SIZE  FOR  MOST  MOLDIHG  JOBSi 


_____  Due  to  its  versatility  In  molding  both 

small  and  large   parts  on  a   profitable  basis,  the  H-P-M 
ounce    Injection    machine    Is    the    molder's    "production    standard". 

H-P-M's  new  nine  ounce  injection  machine  incorporates  many  im- 
proved operating  features  including  fast  plasticization  with  direct  electric 
heat,  gravity  type  material  feed  and  simplified  electrical  circuit.  Speed  of 
each  reciprocating  machine  member  has  been  greatly  increased,  resulting 
in  materially  lowering  overall  cycle  time. 

The  H-P-M  nine  ounce  injection  machine  is  a  completely  integrated 
unit.  In  addition  to  the  major  machine  members/  all  hydraulic  pumps, 
valves,  and  controls  are  designed  and  built  by 
H-P-M.  Undivided  responsibility  to  the  user  is 
thereby  guaranteed,  investigate  the  outstanding 
production  features  of  this  new  H-P-M  nine  ounce 
"all-hydraulic"  unit.  Write  today  on  your  company 
letterhead  for  a  free  copy  of  H-P-M  Bulletin  45O3 
describing  this  versatile  9  oz.  molding  machine. 

THE  HYDRAULIC    PRESS   MFG.    COMPANY 
Mount  Gilead,  Ohio,  U.  S.  A. 

(ranch  ofli«t  In  New  T.tk,    Philadelphia,    Cleveland,   Cincinnati. 
Detroit    and    Chicago,     ftepretentativet   in  other   Principal  Citlen. 


ECTION  MACHINES 

OR    MOLDING    T  H  £  R  M  O  -  P  L  A  5  T  I  C  S 


Chairman  of  the  Board  and  Publisher 
WILLIAM  ».  ZIFF 

Prtsuirnl 
I.  6.  DAVIS 

Secretary-  Treasurer 
ARTHUR  T.  PULLEN 

\  icf-Presidenls 

GEORGE  IERNER 
Advertising  and  Salei  nirtrtor 

MICHAEL  H.  FROELICH 
Kditorial  Dirrclor 

H.  J.  MORGANROTH 
Production  Dirtrtor 

H.  6.  STRONG 

I'.irrulation  IHrrclor 


DECEMBER    •    1946 


\rl  Director 
HERMAN  R.  BOLLIN 


THE  COVER:  Attractiva  Chriitmai  Ir.t  orna- 
mantj  art  mad*  by  Schwab  (  Frank.  Inc.,  of 
fhair  "Frostai"  foam  styrana  (a  Dow  poly- 
ilyrana).  and  told  by  Frank  Paptr  Product! 
Co.,  undar  tradanama  of  "Whita  Christmas" 


IDITORIAL 

Kdilor 
MICHAEL  H.  FROELICH 

Pirld  Kdilor 
WILLIAM  SCHACK 

Auoruttr  r'dilnri 

M    CHURCH 

LILA  SHAFFER 

Writ  (MU!  Kdilor 
GAITHER  LITTRELL 

Hajnino/on  r.<iil>.r 
FRED  HAMLIN 

f  ifniultiitij  Terhniral  Kdilor 
CHARLES  A    SCOGLAND 

Art  Kdilor 
SYDNEY   BARKER 

Staff  PhototrapHrri 

ARTHUR   E    HAUG 

WALTER  STEINHARD 


ADVERTISING 

JAMES  A.  CERIONE 
r.mtrrn  Adrrrlitinf  \lanagrr 

ROY  E    UNDER 
WidW»W  Adrrrluint  Manafr 


in  this  issue 

Know  Your  Low  Pressure  Resins 

Richard  J.  Francis  anil  (lore  E.  Harmi 

(lonipuct  Efficiency  in  Housing 

\l'hat  About  Plastics  in  Shoes? Rnss  Anth»n\ 

Electric  Brush  Features  Plastics 

Protecting  Aircraft   Radar  >>-!•  in- Laurence  O.  Hau/>l.  Jr. 

Extruding  Acrylics James  Haiti  \ 

End-Use  Testing  of  Plastics  Films John  II  .-/XT 

Precision  M..lilm-  I'licnolics S.  A..  W<i.\«.  -~ 

Unusual  Molding  Oeatcs  Radio  Dial C.arl  Simnnsim 

\  inyl  Printing  Plates  Reduce  Ink  Costs I'hil  Hu*kirk 

1  .iiiiiii.iiin-  with  Melamine  Resins T.  H  aln-r  N<»/>/<> 

Heat  Sealing  Plastics  Films r'n-il  Kolili-r 

(ilosure  Performs  Double  Duty 

A  New  Cover  Does  An  Old  Job Philip  P,,lln,k 

Packaging  Test  Meets  Requirements 

A  Df-i^iii-r  Sets  An  Example 

Hand   Marking  Plastic-'  in  Color 

Phcnolics  Replace  Sheet  Steel 

2  ()z  Injection  Press .• 

Mold    I  .-in  1 1. -i  i  inn-  I   i  ml  ml 

departments 

IM.i-iirs  in  Perspective 10 

i  in    the    Drafting    Board 43 

1'1.,-iio.  at  Work 56 

Whal'ii  New  i"  I'la-lir- 71 

I  il.-ralurr  Review 72 

Anoriulion    Art ivilie> 


13 
18 

20 
26 
28 
30 
:i4 
,iH 
to 
44 
4<> 

:>d 
on 

(.2 

1.1 
<•« 

,'!') 

•Ill 


New»  Letter 
Industry    Hi|(hli|Eht- 
People 

Plaxlir*  Overi-ea^ 
The  Pl.i.lir-   I  il.r.ir> 
-i.,li-ii..il  Data 


1«H 


I'rohlriiK.  in  I'la^irs 102 


T.  KaMlrrn  Ditition 
HARLES  R.  TI6HE 

\ltinngrr.    \\rilrrn  /liruion 
WILLIAM   L.    PINNtY 


•  RANCH    OMICIS 

NEW  YORK (H 

Kmfirr  Slalr  Hid*.  »l  7-O'MO 

LOS  AN6ELES  (Ml 

*/i  ,V    11,11  XI  .    ri  rl, 

WASHINGTON   141 
ional  HU,  .  K  \rrulit*  ISO* 

TORONTO 
.'/   ^  inf  Str~1.  Kmit 

LONDON 

.  Ud  .  i.rnn,,,,*.i  111.1, 
l~,dn».   H   S 


COPYRIGHT  It4i 

ZIFF  DAVIS   rUILISHING  COMPANY 

Editorial  Officas.   IK  North  Wabaih  A»a  ,  Chicago  I.  III. 
VOLUME  I     •     NUMIER  4 


Marnbcr 

Audit   luraau  of 

Circulations 


In  addition  to  manual  convenience,  the  famous  Thermex 
drawer  assures  precise  heating  and  a  steady  working 
pace  for  the  operator.  At  the  end  of  each  heating 
cycle,  timer  automatically  resets  to  zero.  Signal  light 
turns  off,  and  the  unit  is  ready  for  the  next  load. 


The  famous  Thermex  drawer  makes  possible  a  highly 
desirable  air  gap  between  material  and  electrodes. 
This  greatly  increases  uniformity  of  heat  in  non-uniform 
materials,  and  reduces  moisture  condensation  by  per- 
mitting proper  circulation  of  air  around  electrodes. 


The  famous  Thermex  drawer  provides  a  large  load 
area  which  permits  maximum  use  of  the  ability  of  high 
frequency  heat  to  uniformly  penetrate  masses  of  mate- 
rial. Drawer  holds  one  large  preform  or  many  small 
ones.  It  is  not  necessary  to  load  preforms  on  top  of 
each  other. 


Designed  around  the  famous  Thermex  drawer,  every 
Thermex  unit  for  the  plastics  industry  is  not  only  simple 
to  operate  but  also  simple  to  install.  Completely  self' 
contained,  Thermex  Red  Heads  can  be  easily  rolled 
into  position  and  from  place  to  place  as  needed. 


Designed  around  the  famous  Thermex  drawer,  com- 
pletely self-contained  Thermex  Red  Heads  do  a  big 
job  with  a  pronounced  absence  of  overall  bulk.  Every 
model  fits  into  present  press  layouts.  You  can  convert 
to  high  frequency  heating  without  upsetting  and  re- 
building your  plant. 


The  famous  Thermex  drawer— master  feature 
of  high  frequency  heating  for  plastics 


npHERMEX  high  frequency  heating  equip- 
A  ment  for  the  plastics  industry  is  dis- 
tinguished from  all  others  by  the  sliding 
drawer  heating  compartment.  This  master 
feature  is  the  key  to  many  THERMEX  fea- 
tures. All  told,  they  give  you  the  line  of 
high  frequency  heating  equipment  that's 
first  for  modern,  efficient,  self-contained 
material  handling  design. 

It's  the  most  complete  line  of  fully  de- 
veloped, convenient,  portable  high  fre- 
quency heating  units  for  plastics.  There's 
a  THERMEX  Red  Head  to  fit  your  needs. 


And  backed  by  the  experience  of  the  organ- 
ization which  developed  the  first  practica- 
ble industrial  high  frequency  dielectric 
heating  equipment,  every  THERMEX  Red 
Head  is  dependable. 

If  you're  going  to  convert  to  the  high 
frequency  preheating  of  plastic  materials, 
find  out  about  THERMEX  Red  Heads. 

Write  to  The  Girdler  Corporation,  Ther- 
mex Division,  Louisville  1,  Kentucky. 
District  offices:  150  Broadway,  New  York 
City  7;  228  North  La  Salle  Street,  Chi- 
cago 1;  1836  Euclid  Avenue,  Cleveland  15. 


The  First  Industrial  High  Frequency  Dielectric  Heating  Equipment 


THERMEXand  REDHEAD—  Trade  Marki  Ken.   V   S.  Pal.  Of 


FIRST 
WITH  THE  MOST 
ADVANTAGES: 


f 

1     The  Famous  Thermex  Drawer 
*    Dual  Timer  Control 
Portability 
Dependability 

Automatic  Signal  Light 
Automatic  Resetting  Timer 
Convenient  Working  Height 
Accessible  Control  Panels 
Large  Load  Area 
Warp  -proof  Load  Tray 
Adequate  Metering 

Overload-Underload  Protection 
Automatic  Safety  Switches 
Air  Gap  with  All  Loads 
Rugged  Construction 
Compact  Design 
Heavy  Duty  Cabinet 
Economical  Use  of  Power 

DECEMBER  1946 


PLASTICS 


STOKES  MOLDING  IS  TfalMf  dutwtafic 


because 


Thc  Piece  Operates 

The  elusive 
ing  the  piece 
means  that  Stokes 
Molding  Machi 
ly  automatic 

Passuthr°U 
trap.  Should  a 

any 


ic 
^ 

sensitive 
ject 


lhe  machine 


**"  °nd  usted  and  auto 

ffiiC*n^ontroUed.  An  auto 
ScpusU  combines  mechan-    | 
action  to  eject  pieces 


Stolcef  Model  235  SO-Ton  Automatic 
Molding  Preii.  Covered  by  U.  S. 
and  ioreign  patent*. 


AUTOMATIC  MOLDING   is  foolproof,  flexible,  economical 


The  above  and  other  Stokes  developments  provide 
molding  presses  that  are  reliable,  foolproof,  eco- 
nomical. An  unskilled  man  can  run  a  battery  of 
them.  These  machines  are  producing  a  wide  va- 
riety of  parts,  in  hundreds  of  shapes  and  sizes,  for 
•uch  diverse  products  as  electrical,  home  and  office 
appliances,  radio  and  electrical  equipment,  auto- 


motive accessories,  toys,  novelties,  many  others. 

Parts  produced  automatically  are  identical,  low 
in  flash  loss,  accurate  in  dimensions,  of  highest 
quality.  Investigate  Automatic  Molding. 

F.  J.  STOKES  MACHINE  COMPANY 

6O40  Tabor   Road.   Philadelphia   10,   P.nno. 


MOLDING  EQUIPMENT 


DKCKMKKK  1! 


•    ENGINEERED    AND    MOLDED    AT    NO.    I    PLASTICS    AVENUE 


A  clear  case  for  plastics 


•  Here's  the  battery  that  speaks  for 
itself.  Its  transparent  case  lets  you  see 
the  liquid-level  at  a  glance  .  .  .  and  a 
hydrometer,  molded  into  the  case,  tells 
the  charge.  It's  the  storage  battery  for 
the  G-E  self-charging  portable  radio. 
During  the  war,  plastics  battery  cases 
proved  their  value  in  walkie-talkies, 
storm  lamps,  and  other  military  items. 
For  this  Willard  storage  battery,  the 
leakproof,  acid-resistant  case  is  injec- 
tion-molded to  exacting  specifications 
by  General  Electric.  The  material  is  poly- 


styrene—lighter than  glass  and  stronger 
than  hard  rubber.  G.  E.'s  complete 
plastics  service  covers  every  step  in 
the  design  and  manufacture  of  plastics 
products. 

Have  you  a  plastics  product  to  de- 
sign? Consult  General  Electric— world's 
largest  manufacturer  of  finished  plastics 
products.  We'll  be  glad  to  send  you  a 
new  booklet,  "What  Are  Plastics?" 
Write  Plastics  Divisions,  Chemical  De- 
partment, General  Electric  Company, 
1  Plastics  Avenue,  Pittsfield,  Mass. 


G-E  Complete  Service— 
Everything  in  Plastics 

BACKED   BY    52    TEARS    OF  EXPERIENCE. 

We've  been  designing  and  manufacturing 
plastics  products  ever  since  1894.  G-E  Re- 
search works  continually  to  develop  new 
materials,  new  processes,  new  applications. 

NO.  I  PLASTICS  AVENUE  — complete  plastics 
service — engineering,  design  and  mold-mak- 
ing. Our  own  industrial  designers  and  engi- 
neers, working  together,  create  plastics  parts 
that  are  both  scientifically  sound  and  good- 
looking.  Our  own  toolrooms  are  manned  by 
skilled  craftsmen — average  precision  mold 
experience,  12  years. 

ALL  TTPES  or  PLASTICS.  Facilities  for  com- 
pression, injection,  transfer  and  cold  molding 
...  for  both  high  and  low  pressure  laminating 
...  for  fabricating.  And  G-E  Quality  Control 
— a  byword  in  industry — means  as  many 
as  160  inspections  and  analyses  for  a  single 
plastic  part. 


GENERAL  11  ELECTRIC 


CO   4i-A18 

GENERAL    ELECTRIC    PLASTICS     FACTORIES     ARE     LOCATED    AT    SCRANTON,    PA.,    MERIDEN,    CONN. 
FORT  WAYNE,  IND.,  TAUNTON,   WEST  LYNN.  AND   PITTSFIELD.   MASS. 


DECEMBER  1946 


PLASTICS 


PENNSYLVANIA   COAL  PRODUCTS  COMPANY 


Manufacturer  of  Penacolite  Resins  and  Adhesives  and  Penocol  Chemicals 
8  PLASTH  S 


PETROLIA.  PENNSYLVANIA 


I)K(  KMHKK   194fi 


TOINV  3QONTON 

Helps"  Run  a  Test  / 


BONNY  BOONTON  in  the  lab  is  apt  to  give 
"help"  no  one  bargained  for.    'Specially  when 
she  decides  to  run  a  test  of  her  own! 

One  test  we  do  run  every  day  at  Boonton  (even 
when  Bonny's  on  hand )  is  what  we  call  the  "boiler 
feed  water  test."  You  know,  the  boiler  is  a  very 
important  factor  in  successful  plant  operation.  It 
provides  steam  to  heat  molds — pressure  to  operate 
hydraulic  presses. 

Development  of  certain  chemical  formations  in  the 
boiler  water  may  clog  up  pipes  or  corrode  them. 
Boonton's  daily  tests  assure  the  chemical  balance 
needed  to  prevent  costly  shut-downs. 

Such  extra  precautions  help  us  deliver  molded 
parts  on  schedule.  If  this  appeals  to  you,  see  us. 

t/\CC  •  We've  got  something  you  might  like  to 
have — a  special  Decimal  Chart,  3-ring  punched  to  fit 
your  notebook.  This  chart  gives  diameter,  area  and 
circumference  of  circles,  and  surface  and  volume  of 
spheres  for  each  additional  fractional  increment  (1/64) 
of  diameter.  Write  us  on  your  company  letterhead  for 
your  copy. 


f 


BOONTON  MOLDING  COMPANY 


MOLDERS  OF  MOST  PLASTICS  BY  MOST  METHODS 


FOR  OVER  25  YEARS 
CUSTOM  ENGINEERS 
OF  MOLDED  PLASTICS 


122  EAST  42nd  ST.,  NEW  YORK  17  • 


SUITE  17I6-P 
MURRAY  HILL  6-8540 


: 


FACTORY— BOONTON.  New  Jersey 


DECEMBER  1946 


PLASTICS 


SOME  EFFORT  has  been  made  in  the  past  few  weeks 
to  arrive  at  an  equitable  solution  to  the  problems 
involved  in  those  activities  of  SPI  and  SPE  which 
overlap.  \Ve  believe  both  organizations  are  extremely 
anxious  to  come  to  some  equitable  understanding  and, 
no  doubt,  each  has  approached  the  problem  with  art 
open  mind. 

To  date,  however,  notwithstanding  numerous  joint 
conferences,  no  tangible  meeting  of  the  minds  has  oc- 
curred. As  a  matter  of  fact,  the  two  organizations 
are  just  as  far  apart  today  as  they  were  when  discus- 
sions first  were  undertaken.  That  is  not  a  criticism  of 
either  organization  but  rather  a  testimonial  to  the  nu- 
merous problems  involved  and  the  difficulties  to  be  sur- 
mounted. Yet,  despite  these  problems,  the  conferees 
can  find  a  possible  guide  if  they  would  only  look  into 
the  record  and  study  the  experiences  of  certain  societies 
associated  with  some  of  the  major  industries  which  are 
to  be  found  in  this  country. 

Take,  for  example,  the  aircraft  industry  which,  like 
the  plastics  industry,  had  two  societies — a  group  repre- 
senting the  manufacturers  and  another  group  repre- 
senting the  engineers.  For  some  little  time  their  activi- 
ties so  overlapped  that  each  was  getting  in  the  other's 
way. 

Before  long,  leaders  of  both  societies  met  to  dis- 
cuss  their  problem,  and  they  finally  came  up  with  a 
solution  which  was  based  on  precedent — a  similar  sit- 
uation in  the  automotive  industry.  Taking  the  automo- 
bile industry  as  a  guide,  the  aircraft  industry  decided 
to  separate  its  function  into  a  management  group  and 
an  engineering  group. 

In  line  with  the  plan,  the  group  representing  manage- 
ment was  charged  with  the  responsibility  of  acting  as 
the  industry'-,  mouthpiece  in  Washington  for  national 
affairs  and  in  inter-industrial  activities.  It  performed 
i In  promotion  ;in<l  public  relations  for  the  industry  as 
a  whole,  and  it  ran  the  industry  show.  It  had  nothing 
i"  ilo  with  engineering  basically,  and  it  reserved  that 
imjxirtant  work  for  the  engineering  society.  That  divi- 
sion of  the  industry  was  charged  with  the  rrx|xinsihility 
of  fostering  engineering  development  only  and  of  con- 
ducting the  highly  iin|x>rtant  engineering  forums.  In 
addition,  it  publishes  a  maga/iiu-  in  which  only  highly 
technical  article--  appear.  The  management  group,  on 
the  other  hand,  publishes  the  industry's  annual,  or  did 
at  one  lime. 

This  is  the  logical  liasis  on  which  the  automotive  and 
aircraft  industries  function,  and  it  is  also  a  liasis  on 
which  other  technical  industries  in  the  country  func- 
tion Since  it  has  proved  its  worth  through  the  years, 


it  might  conceivably  present  a  model  with  which  the 
plastics  industry  can  reach  a  decision  on  what  to  do 
with  its  societies.  It  might  be  pointed  out  that  in  the 
long  run  the  reasons  motivating  a  clearer  cut  division 
of  responsibility  in  these  other  industrial  associations 
were  based  primarily  on  the  premise  that  the  industry 
should  be  the  greatest  beneficiary  of  what  activities  its 
associations  undertook. 

It  should  certainly  be  obvious  that  no  industry  can 
benefit  materially  when  its  major  associations  are  prac- 
tically in  conflict  with  each  other  on  major  issues.  The 
two  plastics  shows  scheduled  for  Chicago  are  typical 
of  what  could  happen  where  there  is  a  division  of 
thought  as  to  who  should  do  what.  No  real  tangible 
effort  seems  to  have  been  made  by  either  the  SPI  or 
the  SPE  at  this  time  to  give  up  any  of  the  jobs  that 
they  have  been  doing.  Yet,  sacrificing  something  by 
each  side  is  going  to  be  the  only  soltition  to  this  whole 
problem. 

We  do  not  intend  to  offer  the  experience  of  the  auto- 
motive and  aviation  industries  in  the  solutions  of  their 
problems,  as  panaceas  or  ideals  upon  which  the  plastics 
industry  can  build  its  own  associations.  We  do,  how- 
ever, point  them  out  in  the  hope  that  maybe  somewhere 
along  the  line  they  will  offer  a  guide  to  the  answers. 
For.  until  such  an  answer  is  found,  despite  all  the 
previous  efforts  expended  by  everylxidy  in  doing  a 
constructive  job,  the  plastics  industry  will  not  reap  all 
the  benefits  which  it  normally  looks  for  and  expects 
from  its  associations. 

*  *     * 

WHAT  EVERY  saleslady  should  know  :  According  to 
the  latest  DuPont  brochure  on  nylon,  that  word 
is  not  a  trade  name  but — hold  your  breath  now — "a 
generic  term  for  any  long-chain  synthetic  polymeric 
amide  which  has  recurring  amide  groups  as  an  integral 
part  of  the  main  polymer  chain,  and  which  is  capable 
of  being  formed  into  a  filament  in  which  the  structural 
elements  are  oriented  in  the  direction  of  the  axis  " 

*  *     * 

WE  VIEW  with  some  alarm  the  notion  of  many 
chemists  that,  because  of  the  importance  of  chem- 
istry in  modern  living,  they  are  individuals  somewhat 
set  apart  from  the  common  run  and  hence  can  make 
authoritative  pronouncements  about  philosophy,  poli- 
tics, literature,  and  any  other  subject  which  "swims  into 
their  ken." 

Shouldn't  we  tell  them  that  the  great  men  in  the 
development  of  chemistry  and  of  plastics  held  no  such 
delusions  -  i  xn 


10 


STI  t'9i 


DKCKMHKK   1946 


Squeeze  Play 


for  Better  Plastics 


Hobbing  is  a  good  economical  way  of  producing  many 
molds  for  plastics.  But  when  we  installed  a  bobbing  press  in  our  own 
plant,  back  in  1924,  the  idea  made  history.  Made  sense,  too.  It  gave  us  a 
unique,  complete  toolroom — with  full  control  over  all  mold  production. 


'HEN  AN  INDUSTRY  keeps  improving  production  techniques— 
keeps  producing  larger  pieces,  from  materials  of  more  universal  but 
more  precise  characteristics— and  keeps  doing  it  faster —that's  progress. 
What's  more,  that's  Plastics! 

We're  showing  you  our  contributions  to  progress  in  plastics  for  just 
one  reason.  These  ideas  all  benefitted  our  customers  before  they  became 
general  molding  practice.  They  paid  off— in  actual  figures. 

Why  not  give  your  firm— today— the  advantage  of  some  of  tomorrow's 
bright  ideas?  Send  for  your  free  copy  of  "A  Businessman's  Guide  to  the 
Molding  of  Plastics"— or  ask  for  a  Kurz-Kasch  engineer. 

Kurz-Kasch 


For  Over  29  Years 

Planners  and  Molders  in  Plastics 


Kur/-Kasch,  Inc.,   1413  S.  Broadway,  Dayton  1,  Ohio.  Export  Offices:  89  Broad  Street,  New  York,  N.  Y. 
Branch  Sales  Offices:  New  York  •  Chicago  •  Detroit  •  Los  Angeles  •  Dallas  •  St.  Louis  •  Toronto,  Canada. 


DECEMBER  1946 


PLASTICS 


11 


AMOS 

tUtt  <lt .  ,  , 

RIGHT! 


'  / 


?&  , 


'JS 


Transparent,  molded  escutcheon-plat* 
above  is  lacquer-coated  on  back  to  pro- 
duce a  beautiful,  mar-proof,  silver-like 
finish.  Finished  assembly  it  left 


WHITHIR       YOU     NliO 


OFFICI  MACNINCS  OK  IN005HIAL  COUir»[NT 


TOOL*  U»IO» 


0f  day/Any  £fo  Matt  f 
' 


It's  an  escutcheon  for  the  cold  control  on  a.  well-known  refrig- 
erator. Amos  molded  it  of  clear  polystyrene,  for  transparency, 
dimensional  stability,  and  resistance  to  moisture.  It  is  shaped 
to  fit  perfectly  all  curving  contours  in  the  throat-lining. 

Spray-coating  the  back  of  the  transparent  plate  with  a  special 
aluminum  lacquer  produced  a  permanent  silver-like  finish,  im- 
possible to  scratch  or  mar.  Thus,  Amos  delivered  a  molded 
plastic  escutcheon-plate  superior  in  beauty  and  in  utility.  In 
every  respect  Amos  did  the  job  right! 

Every  step  of  every  Amos  molding  job,  from  designing  to 
finishing,  is  handled  by  experienced  specialists  in  plastics 
engineering.  For  injection  molded  parts  and  products  that 
excel  in  design,  accuracy  of  molding,  and  quality  of  finishing, 
just  send  your  drawings  or  write  us  what  you  have  in  mind. 
Amos  will  do  it  right! 

AMOS    MOLDED    PLASTICS  •   EDINBURGH,  INDIANA 

Division  of  Amot-Thomptofi  Cofporotion 

On*  at  lh«  Moil  Modern  f  laitic  Molding  Plonli  In  lh«  lndu«h-y 


12 


I)K(  KMHKK  1946 


An  application  of  low  pressure 
molding  techniques  is  seen  in 
these  low  electrical  loss  lam- 
inates, which  are  produced  by 
Formica  Insulation  Co.,  and 
used  in  electronic  equipment 


Know  Your 


.    ^rranciA   ana 

Owens-Corning   Fiberglas  Corp. 


C-. 


Glass  cloth-resin  laminated  core  material,  in  shape  of  "fig- 
ure 8,"  is  produced  by  Cycleweld  Div.  of  Dodge  Motors  Co. 


THK  SUCCESSFUL  applications  of  low  pressure  mold- 
ing techniques  have  been  so  numerous  and  varied  that 
it  is  sometimes  difficult  to  fully  appreciate  the  vastly  broad- 
ened scope  of  the  niolder.  The  achievement  of  hitherto 
undreamed  of  moldings,  unusual  both  as  to  size  and  shape 
and  with  a  variety  of  physical  characteristics  is  largely  due 
to  the  excellence  and  effectiveness  of  the  low  pressure  resins. 
Two  broad  types  of  resins  are  generally  employed  in  low 
pressure  molding — the  polyesters  and  the  low  pressure  phcn- 
olics.  The  resins  composing  the  first  group  are  variously 
known  as  modified  alkyds.  alkyd  stymies,  allyls,  contact 
pressure  unsaturated  polyester  and  impression  molding  res- 
ins. The  low  pressure  phenolics  are  phenol  formaldehyde 
rrsins  tailor-tnade  to  mold  at  pressures  as  low  as  15  psi. 
They  are  available  as  water-alcohol  solutions  containing  (>()' ,, 
to  70%  solids  and  as  powders  suitable  for  dusting  on  a  rein- 
forcement and  for  molding  without  the  use  of  solvents. 

As  used  in  this  discussion  the  term,  unsaturated  polyester, 
describes  a  group  of  resins  relatively  new  to  the  plastics 
fabricator.  They  differ  from  the  older  and  better  known 


DECEMBER  1946 


13 


Skydyne  Sales  Co.  otters  sandwich  panels  with  sheet  alumi- 
num face*  and  core  materials  of  balsa  and  cellulose  acetate 

re-ins  in  several  respects:  (1)  They  are  supplied  in  a  fluid 
>tatr.  varying  in  viscosity  from  20  to  600,000  centipoises. 
(2)  L'ndcr  normal  curing  conditions  they  are  converted  to 
the  cured  state  without  the  evolution  of  volatiles  thereby 
making  it  possible  to  convert  100  Ib  of  uncured  resin  into 
100  Ib  of  cured  resin.  (3)  A  molded  part  with  good  physical 
properties  can  be  produced  without  the  necessity  for  apply- 
ing pressure  to  the  resin  during  the  curing  cycle. 

The  combination  of  new  properties  inherent  in  the  un- 
saturated  polyesters  has  invited  the  development  of  new 
molding  techniques  and  the  production  of  larger  plastics 
parts.  The  polyesters  are  transparent  and  clear  with  the 
exception  of  a  slight  to  sometimes  intense  straw  color.  Rea- 
sonably color-free  resins  are,  however,  available  for  exacting 
applications.  Vncured  polyesters  are  soluble  in  ketones  and 
aromatic  and  chlorinated  hydrocarbons.  Most  commonly 
used  solvents  are  acetone,  benzol  and  carbon  tetrachloride. 
in  that  order. 

Fabricators  are  cautioned  not  to  use  solvents  ;is  diluents 
for  the  uncured  resin;  for  if  traces  of  solvent  remain  they 
are  likely  to  volatilize  during  the  cure  and  so  produce  a 
porous  structure  in  the  finished  part.  If  a  diluent  is  needed 
to  thin  the  resin,  monomeric  styrene  is  recommended.  I'nder 
some  conditions  the  styrene  reacts  and  becomes  an  integral 
part  of  the  resin.  Whenever  added,  it  should  not  be  sub- 
jected to  a  flash  cure  which  may  cause  the  styrene  to  volatil- 
ize. Although  it  appreciably  speeds  up  the  rate  at  which  the 
resin  wets  out  the  reinforcement,  styrene  will  alter  the  prop- 
erties of  the  cured  resin;  and  since  the  manufacturers  add 
styrene  to  many  of  the  resins,  it  should  be  used  sparingly  and 
only  on  his  advice.  Monomeric  styrene  is  quite  volatile  ami 
h"iild  therefore  be  kept  in  a  closed  container. 

Types  of  Polyesters  Available 

There  are  throe  t\|>es  of  unsaturated  polyesters  available, 
the  rigid,  flexible  and  self-extinguishing  resins.  During 
cure  the  rigid  resins  convert  to  a  hard,  infusible  state.  As 
its  name  indicate-,  the  second  type  is  flexible  in  the  cured 
Mate.  These  are  miscible  in  all  proportions  with  the  rigid 
type  thereby  making  jxissililr  an  unlimited  number  of  coin 
hinations  with  intermediate  degrees  of  stiffness.  The  flcx- 
ilili-  re-ins  are  relatively  new  and  will  undoubtedly  find  con- 
siderable use  in  decorative  applications.  Virtually  all  the 
rigid  and  flexible  resins  burn  when  in  contact  with  a  flame; 
and  continue  to  burn,  although  at  a  slower  rate,  when  the 
flame  is  withdrawn.  Self-extinguishing  resins  burn  but  will 
cease  burning  as  soon  as  the  flame  is  withdrawn.  Self 
extinguishing  resins  arc  commercially  available  in  only  tin- 
rigid  type  of  rrsin. 


High  strength  ratio  and  heat  resistance  ol  "Phenopreg"  and 
"Fiberglas"  is  utilized  in  air  duct  and  scoop  lor  oil  cooler 


A  decorative  out-door  Christmas  bell  is  laminated  by  Indus- 
trial Plastics  ol  "Laminae  4201"  and  'TiDeiglas  Mat  T-34A 


14 


PLASTiCfi 


DECKMKKR  1946 


'I  he  initial  handling  of  the  resin  is  extremely  important. 
As  soon  as  it  is  delivered  to  the  fabricator  it  should  be 
stored  in  a  closed  container  and  placed  in  a  dry  room.  The 
storage  life  of  the  resin  depends  on  two  factors ;  ambient  tem- 
perature and  the  exclusion  of  daylight.  Low  temperatures 
prolong  storage  life  while  exposure  to  ultraviolet  light 
shortens  storage  life  of  styrene  containing  polyesters.  Gen- 
erally, if  the  resin  is  protected  from  ultraviolet  light  and  if 
the  ambient  temperature  of  the  resin  is  below  60°  F,  then  a 
,-tnrage  life  of  from  two  to  four  months  may  be  expected. 

The  contact  pressure  resins  cure  by  polymerization.  A 
slow  reaction  is  already  in  progress  when  the  fabricator  re- 
ceives his  resin ;  thus  accounting  for  its  finite  storage  life. 
The  addition  of  a  suitable  catalyst  will  speed  up  the  reaction 
rate  at  recommended  curing  temperatures  and  reduce  the 
cure  time  to  a  commercially  feasible  point.  Commonly  used 
catalysts  for  contact  pressure  resins  are  organic  peroxides ; 
tertiary  butyl  hydroperoxide  (Union  Bay  State  Co.,  Corn- 
bridge,  Mass.)  for  casting  operations  and  benzoyl  peroxide 
(Lticidol  Corp..  Buffalo,  N.  Y.)  for  laminating  operations. 


Damper  housing  and  damper,  showing  gear  motor  on  damp- 
er spline,  is  low  pressure  molded  by  Airply  Forming  Co. 


A  variety  of  combinations  of  plastics  resins  and   rein- 
forcing fillers  are  now  used  in  the  production  of  boats 


Tertiary  butyl  hydroperoxide  is  a  liquid  and  can  easily  be 
stirred  into  the  contact  pressure  resins.  Benzoyl  peroxide  as 
a  100%  active  material  in  granular  form  can  be  dissolved  in 
a  fairly  thin  resin  with  prolonged  stirring.  A  more  conve- 
nient form  of  the  catalyst  is  a  paste  composed  of  equal  parts 
of  benzoyl  peroxide  and  tricresyl  phosphate.  The  paste  will 
stir  into  the  resin  easily,  but  since  the  paste  contains  only 
50%  active  material,  twice  as  much  must  be  used.  The  addi- 
tion of  catalyst  reduces  the  storage  life  of  the  uncured  resin 
to  a  few  days. 

Curing  Resins 

Polyester  resins  are  converted  from  an  uncured  fluid  to 
a  useful  rigid  form  by  the  application  of  heat  supplied  either 
by  internally  heated  molds,  hot  air  (as  in  an  oven),  or  infra- 
red lamps.  Length  of  curing  time  depends  upon  the  time 
necessary  to  hold  the  resin  at  curing  temperatures  to  reach 
the  thermoset  state ;  this  may  vary  for  different  types  of 
resins.  Curing  temperatures  usually  range  from  200  to 
275°F.  At  higher  temperature's  and  with  heavier  concen- 
trations of  catalysts'  cure  time  is  reduced.  In  general,  slow 
cures  produce  somewhat  stronger  plastics  parts  than  rapid 
cures.  Each  resin  manufacturer  makes  definite  recommenda- 
tions about  catalyst  additions,  cure  temperatures,  and  cure 
times  for  his  product.  He  should  be  consulted  and  his  in- 
structions followed  for  best  results. 

As  a  polyester  resin  is  heated  at  the  start  of  the  cure 
cycle,  it  becomes  less  viscous  and  flows  readily,  but,  as  the 
polymerization  of  the  resin  progresses,  it  reaches  a  stage 
where  it  is  gelatinous  in  nature.  Additional  heating  will 
then  impart  the  desired  hardness  and  strength  to  the  plas- 
tics. Resins  of  this  group  do  not  require  pressure  dur- 
ing cure  to  obtain  finished  piece  with  excellent  qualities. 
Where  a  reinforcement  is  used  with  the  resin  some  pres- 
sure is  usually  used  during  the  cure  cycle.  An  interesting 
characteristic  of  the  unsaturated  polyester  resins  is  the 
liberation  of  considerable  self -generated  heat.  In  a  slow- 
cure  of  a  large  thin  piece  this  exothermic  heat  need  not  be 
considered  for  it  is  dissipated  into  the  surroundings  as  rap- 
idly as  it  is  liberated.  On  fast  cures  (5  min  or  less)  of  thin 
sections  (J4"  or  less)  and  also  in  relatively  slow  cures  of 
thicker  sections,  it  is  desirable  to  consider  this  exothermic 
heat  in  the  early  stages  of  the  design  work.  Properly  con- 
sidered, the  exothermic  heat  can  be  utilized  to  hasten  cure 
cycles  and  production.  Disregard  of  the  potentialities  of 
exothermic  heat  may  allow  the  resin  temperature  to  rise  con- 
siderably above  its  recommended  cure  temperature  thereby 
producing  a  molded  part  with  inferior  properties. 

The  effect  of  exothermic  heat  can  be  explained  by  exam- 
ining the  cure  cycle.  When  the  resin  is  slowly  raised  from 
room  temperature  to  its  recommended  curing  temperature, 


MILL    ROLL 


I~~              HOT 

AIR 

CHAMBER 

t\ 

n 

V  V                           I  \ 

J 

'^ 

)  ' 

»  ' 

i  r                          \  r 

1  =r 

COOLING 
ARCH 

|                  HOT 

AIR 

CHAMBER 

DOCTOR  KNIVES          DRYING    OVEN 


J 


REWIND 
ROLL 


VARNISH  COATING  PAN 
WITH    DIP    ROLL 

Two  side  coating,  dip-and-flow  method 


SQUEEZE 
ROLLS 


HOT  AIR  CHAMBER 

7~l TS TA- 


AIR CHAMBER 


COOLING 
ARCH 


REWIND 
ROLL 


DRYINJG   OVEN 

VARNISH  COATING  PAN 
WITH  DIP  ROLL 

Two  tide  coating,  squeeze-roll  method 


o 


HOT   AIR  CHAMBER 


HOT  AIR  CHAMBER 


DRYING    OVEN 

VARNISH 
COATING  PAN 

One  side  coating,  squeeze-roll  method 


[COOLING 
ARCH 


REWIND 
ROLL 


exothermic  heat  is  liberated  at  a  correspondingly  slow  rate 
and  is  dissipated  alni«>t  as  last  a-  it  is  liberated.  Thus,  the 
temperature  of  the  resin  follows  about  the  same  time-tem- 
perature cycle  as  the  heat  source.  When  it  finally  reaches 
its  normal  cure  temperature,  the  resin  has  already  advanced 
considerably  in  the  cure  cycle.  Further  heating  at  the  rec- 
ommended cure  temperature  completes  the  reaction,  although 
the  exothermic  heat  given  off  in  the  last  stages  of  the  reac- 
tion is  not  sufficient  to  heat  the  resin  appreciably  above  the 
mold  tem|>erature. 

Another  extreme  in  curing  conditions  appear-  in  a  pro- 
duction unit  when  resin  at  room  temperature  is  introduced 
into  a  heated  metal  mold.  In  this  case  the  film  of  resin  in 
immediate  contact  with  the  hot  mold  is  brought  rapidly  to 
the  mold  tctinx-rature.  The  film  of  resin  cures  rapidly,  and 
the  exothermic  heat  produced  raises  the  tem|ierattire  of  the 
n-siii  film  above  the  temperature  of  the  mold.  This  tempera- 
ture differential  causes  heat  to  flow  back  into  the  mold  ;  and 
the  higher  temperature  of  the  resin  film  c.ui-<  -  .1  more  rapid 
(low  of  heat  into  the  resin  beyond  the  film.  This  increase 
in  temperature  offers  a  convenient  and  rapid  method  of  -up 
plying  the  heat  necessary  to  bring  the  resin  up  to  its  curing 
temperature.  I-  miulative  and  as  this  reaction 

progrr >-«••.  through  the  resin,  the  temperature  oi 
rr-in  layer-  tends  to  become  progressively  higher.    To  some 


extent  this  tendency  can  be  counteracted  by  removal  of  heat 
through  the  mold,  and  therefore  it  is  desirable  to  have  the 
mold  made  of  a  material  having  a  high  coefficient  of  thermal 
conductivity  to  achieve  the  highest  buffering  action  from 
the  mold. 

In  the   following  table  are  listed  approximate  values  of 
thermal    conductivity    (K)    for    several    materials   at   room 
temix-ratiire.    The   values  are   in    H'IT"s  |wr  hr,  per   sc[  ft, 
per  in.  thickness.  JMT  degree  F: 

Aluminum  ..........................    14(>l 

Brass   ..............................     Tun 

I  "oncrete    ........................... 

Copper  .............................    -7"" 

l-'iU-r  i  .lass  Keinforccd  Plastics  ........ 


Iron    ..  ...................     4?n 

1  Master  of  Paris  ......................          4 

Steel    ...............................       .*»> 

It  seems  re.ison.iMe  to  assume  that  alxnit  the  same  iela- 
tiotiship  would  exist  in  the  conductivity  values  for  these  ma- 
terials in  the  curing  temperature  range  for  the  re-ins,  which 
is  usually  U-tween  _'.'?  K.  and  300"  F.  for  rapid  curing  con- 
ditions. If  so.  then  cop|x-r,  aluminum,  bra—,  ami  iron  would 
be  selected  for  mold  construction,  and  in  that  order.  Other 
(Continued  on  page  97) 


16 


i*  I.. \tiTH-9i 


m:<  KM  i  IKK 


Humiififipr-<-ontritl  flout,  cup,  ami  rap  m-.tltletl  fcv 
>m    l;,,l,Mrii's.  Inc..  for  Ciavluml  Humidifier  Cu. 


Transparent 

Tenite 
Float  Control 

The  heart  of  this  furnace -humidifier  control  is  a 
Tenite  float  encased  in  a  transparent  Tenite  cup. 

For  the  float,  the  designers  sought  a  material  light 
in  weight  and  dimensionally  stable,  which  would 
not  corrode,  leak,  or  waterlog.  For  the  outer  cup, 
they  wanted  a  substance  more  shock -resistant  than 
glass,  yet  transparent,  so  that  the  inside  water  level 
and  drip  feed  would  always  be  visible.  And  in  each 
instance,  they  found  the  right  combination  of  prop- 
erties in  Tenite.  Moreover,  this  plastic  offered 
economies  in  production,  because  of  the  speed  and 
accuracy  with  which  it  could  be  molded. 

The  properties  which  suit  Tenite  to  this  purpose 
have  led  to  its  use  in  many  similar  products,  such 
as  rain  gages,  manometers,  anti-freeze  testers,  and 
oil  feed  cups.  For  applications  in  other  fields, 
Tenite  provides  unlimited  color  possibilities,  elec- 
trical and  thermal  insulating  properties,  high  luster, 
and  a  surface  that  is  always  pleasant  to  the  touch. 
For  more  information  about  Tenite,  write  to 
TENNESSEE  EASTMAN  CORPORATION  (Subsidiary  of 
Eastman  KodakCompany),KiNCSPORT,TENNESSEE. 


TENITE  AN  EASTMAN  PLASTIC 


Building  Compact  Efficiency 


in  Housing 


Fuller  House  in  a  landscaped  setting.  Economy  was  sought  in 
material  conservation  rather  than  in  use  of  inexpensive  ma- 
terials. Plastics,  therefore,  contribute  much  to  its  design 


THE  IMMEDIATE  need  for  low-cost,  efficient  housing, 
produced  speedily  in  large  quantities  and  easily  trans- 
portable to  all  areas  where  demand  exists,  has  focussed  wide- 
spread interest  on  the  first  models  of  the  aluminum  Fuller 
House.  This  is  the  cylindrical  structure  hung  on  a  central 
mast,  which  was  designed  by  J.  Buckminster  Fuller,  who 
achieved  prominence  with  his  Dymaxion  house  nearly  20 
years  ago. 

In  order  to  produce  a  compact,  movable,  mass-produced 
house,  Fuller  engineers  figured  that  a  minimum  of  weight, 
with  a  maximum  of  efficiency  for  each  pound  of  weight,  was 
necessary.  Economy  was  to  be  sought  in  the  conservation  of 
materials,  rather  than  in  the  use  of  inexpensive  materials. 
Plastics,  therefore,  contribute  a  share  to  this  new  "design 
for  living." 

The  outstanding  plastics  application  is  the  completely  en- 
circling window,  comprised  of  300  sq  ft  of  methyl  meth- 
acrylate  sheet,  which  encloses  the  house.  Acrylic  is  admir- 
ably suited  to  the  particular  requirements  of  this  unusual 
type  of  construction.  A  lightweight  material  with  K<«M| 
impact  strength  was  necessary,  since  the  house  will  be 
packed  in  a  metal  container  16  ft  long  and  4J  j  ft  in  diameter, 
for  shipment,  and  a  material  which  might  break  or  shatter  in 
trans|M>rt  o>uM  not  t>c  used.  Good  tensile  strength  was  also 
required  of  the  window  material,  since  it  is  an  integral  struc- 
tural im-mU-r,  and  supported  in  tension  from  tin-  central 
mast. 

Assembly  It  Facilitated 

Furthermore,  the  same  material  which  so  adequately  per- 
forms these  design  functions  possesses  traits  which  facilitate 
lily  to  the  house  at  the  site.  Its  resilience  and  flex- 
ibility enable  each  of  the  twenty-five  panes  to  assume  the 
slight  curve  nere-ary  for  the  house  circumference  of  ap- 
proximately 113  ft,  without  forming.  Assembly  is  further 
expedited,  and  provision.,  for  future  replacement  insured,  by 
the  fact  that  acrylic*  can  be  drilled.  The  panes  are  thereby 


assembled  to  aluminum  moldings  horizontally  and  vertically 
with  removable  fasteners. 

Since  the  house  will  be  distributed  through  a  national 
chain  of  dealers,  service  will  be  provided  in  case  of  acci- 
dental damage.  Replacement  panes  will  be  carried  in  stock. 

In  addition,  buyers  will  be  instructed  in  maintenance  of 
the  acrylic  material  used  in  the  house,  such  as  the  \*-*i 
methods  of  cleaning  it  and  the  care  necessary  to  protect 
its  surface  from  scratches.  They  will  also  be  informed  of 
the  possible  fading  effects  of  actinic  rays,  which  acrylic 
transmits,  on  furniture  and  fabrics,  so  that  they  may  take 
the  necessary  precautions. 

Another  contemplated  use  of  acrylic  is  to  provide  dtist- 
free  enclosures  for  hat-racks  in  the  three  revolving-door 
closets  of  the  house. 

For  comfortable  summer  exposure,  the  acrylic  window- 
may  be  removed,  but  their  substitute  will  be  still  another 


"Fiberglas"  draw  curtains  and  built-in  traverse  rods. 
Curtains  lit  sweeping  contours  ol  the  300  square  leet 
ol  "Plexiglas"  window  encircling  the  Fuller  House.  Be- 
low, window  is  fastened  on  present  model  by  riveting 


18 


ri..\srt <  * 


I)K(  KMHKR  1946 


First  model  of  new-type,  portable, 
mass-produced  house  features  the 
extensive  use  of  various  plastics 
materials  in  its  component  parts 


plastics,  as  built-in  fresh-air  screens  of  olive  drab  I.innitc 
are  provided.  They  are  permanently  fixed  in  place,  sepa- 
rate from  the  windows,  and  are  rolled  down  when  not  in 
use.  The  screens  are  commercially  woven  from  Saran 
(vinylidene  chloride)  filaments  of  .012  diameter  in  a  No.  16 
mesh.  They  were  chosen  for  their  rust-  and  mildew-proof 
qualities. 

The  house  has  no  separate  inner  walls,  but  the  inside  of 
the  aluminum  "skin"  is  covered  with  Naugahyde,  a  nylon- 
coated  fabric  having  the  appearance,  feel,  and  flexibility 
of  leather.  It  is  also  fire-resistant. 

Coated  Steel  Doors 

Incorporated  in  the  prototype  models,  and  contemplated 
for  production  depending  upon  the  availability  of  materials, 
rare  Modernfold  interior  doors  which  open  and  close  like  an 
accordion.  These  are  of  steel,  coated  with  Fabrikoid.  The 
entire  door,  assembled  with  the  synthetic  fabric,  is  procured 
by  Fuller  from  sub-contractors. 

Continuous  built-in  traverse  rods  extend  around  the 
house,  and  draw  curtains  are  offered  as  extra  accessories. 
Thus  far,  Fibcrylas  curtains  are  contemplated. 

It  is  not  expected  that  the  houses  will  be  in  volume  pro- 
duction until  late  in  1946  or  early  1947,  and,  as  the  company 
states,  "availability  of  materials  in  a  fluctuating  market, 
and  final  test  reports,  may  yet  dictate  some  changes  in 
original  engineering  assumptions."  Therefore,  the  fore- 
going account  represents  the  extent  of  plastics  uses  already 
decided  upon  or  contemplated  in  the  Fuller  House.  The 
company  is  fully  cognizant  of  many  other  plastics  possi- 
bilities, and  believes  that  wider  use  of  plastics  than  that 
originally  planned  is  likely. 

The  bathroom,  which  is  at  present  being  stamped  from 
four  pieces  of  sheet  aluminum  and  features  built-in  medicine 
chest  with  mirror,  concealed  plumbing,  heating,  and  vent- 
ilating controls,  is  being  studied  by  Fuller  -engineers,  in 


Unusual  in  design,  "Modernfold"  steel  interior  doors  open 
and  close  like  an  accordion;   are  coated  with  "Fabrikoid" 

conjunction  with  the  outside  suppliers  and  fabricators  of 
these  parts,  to  determine  which  of  many  available  plastics 
can  be  used.  Also  projected  are  kitchen  knobs  and  handles 
in  various  plastics.  But  in  both  cases,  availability  of  mate- 
rials, as  well  as  their  properties,  will  determine  use. 

Other  possibilities  include  the  use  of  plastics  or  impreg- 
nated plywood  for  ceiling  gores,  window  $ills,  corrugated 
partitions  between  the  bedrooms  and, living  rooms,  and 
soundproof  subMances  in  closet  cnvc  wallb  and  m^Mp'slu-ll. 

Thus,  plastics  will  help  Mr.  Fuller  in  anotUttfjnempt  to 
demonstrate  his  contention  that  housing  has^BPace  in  the 
developing  pattern  of  mass  production  technology,  along 
with  automobiles,  refrigerators,  and  the  rest.  END 


Adding  dignity  and  beauty  to  the  bedroom,  aluminum  walls  beneath  the  windows  are  covered  with  "Nauga- 
hyde."   This   nylon-coated   fabric   has   the   appearance    and    feel    oi    leather,    is    flexible    and    fire-resistant 


(0 


Stunning  platform  pumps  of  "Velon"  brocade  evidence  the  beauty, 
softness  and  drapability  of  this  vinylidene  chloride-based   fabric 


What  About 


Footwear  offers  a  large  market;  but  first,  needs  of  the  industry  must 
be  thoroughly  analyzed,  and  new  materials  developed 


f< 


o6A 


*y 


WHI-'.X  the  plastics  manufacturer  studies  the  shoe  in- 
dustry as  a  potential  market,  he  sees  an  apparently 
promising  picture.  In  1942  and  in  1945  an  all-time  high  of 
500  million  pairs  of  shoes  were  produced;  in  1947  this  fig- 
ure is  expected  to  rise  to  600  million  pairs,  with  still  higher 
output  prohable  for  1948  and  1949.  These  figures  repre- 
sent a  market  using  about  15  billion  square  feet  of  shoe- 
ing materials  a  year.  If  plastics  comprised  only  10% 
"t  this  market,  that  would  indicate  an  outlet  for  150  million 
-<iuarc  feet  and,  figuring  even  at  the  current  leather  price  of 
,I!H. ut  30c  per  square  foot,  a  volume  of  about  $50,000,000. 

Hut  the  picture  is  not  so  bright  as  it  veins.  Shoe  manu- 
facturers today  arc  not  over  eager  to  welcome  plastics. 
I  hiring  the  war,  when  leather  was  scarce,  the  industry  em- 
braced plastics  aiming  other  substitutes — but  purely  as  MI!>- 
stitutcs.  However,  soon  after  the  first  plastics  shoes  were 
marketed,  consumer  and  retailer  complaints  filtered  in,  and. 
although  some  excellent  formulations  of  plastics  for  foot- 
-ubsequently  were  developed,  the  shoe  manufacturer  is 
-till  somewhat  susp 

The  reasons  are  plain.  First,  the  bulk  of  the  plastics 
used  in  war-time  footwear  \va*  not  specifically  and  properly 


formulated  foe  that  application.  It  is  estimated  that  lo> 
than  8%  was  expressly  manufactured  for  shoes.  Since  a 
large  part  of  the  remaining  92%  was  made  up  of  cable  scrap, 
it  is  not  surprising  that  performance  was  unsatisfactory. 
To  name  only  one  trouble,  the  non-porous  nature  of  the 
material  was  not  taken  into  account  in  the  construction  of 
the  shoe.  Like  patent  leather,  patent  plastics  prevents  the 
evaporation  of  sweat,  and  it  will  therefore  c;tu-e  painful 
drawing  of  the  feet  unless  an  interliner,  of  which  there  are 
several  good  ones  available,  is  built  into  the  shoe  to  absorb 
the  sweat.  Then,  too,  good  clear  colors  were  difficult  to 
obtain.  Yet  even  during  the  war,  plastic-  i;avi-  ^.\\\-' 
— in  quality  sli,«-,  selling  at  Sld.'i.s  (for  women)  ami 
(for  children).  Yet  the  average  shoe  manufacturer  still 
does  not  know  that  there  are  already  some  excellent  plastics 
for  footwear. 

Even  though  the  opinions  of  the  shoe  industry  regarding 
the  place  of  plastics  in  the  shoes  of  tomorrow  are  grounded 
largely  on  misinformation  or  lack  of  information,  and  on  the 
performance  of  unsuitable  formulations,  if  the  plastics 
manufacturer  is  to  realize  the  tremendous  potential  market 
in  shoes,  he  must  certainly  be  acquainted  w  ith  what  the  shoe 
industry  is  thinking  ami  doing  alxnit  plastics.  What  is  to 
be  said  in  this  article  about  the  shoe  industry's  attitude  is 
based  upon  a  number  of  polls  conducted  amoni:  shoe  manu- 
facturers, supplier*,  retailers,  and  consumers;  interviews 


20 


I*  I.. 1ST  11   * 


I)K(  KMHKR  1946 


N, 


O,  we  didn't  dream  about  ghosts  or  sheep;  we  dreamed  about  that  future 
time  when  we'd  have  the  pride  and  pleasure  of  soliciting  your  business. 
We  dreamed  about  the  sales  story  we'd  tell  .  .  .  how  Michigan  Molded  engineers 
could  alertly  assist  you  in  designing  your  product  in  plastic  or  suggesting  minor 
changes  to  lower  cost  or  enhance  utility. 

We  dreamed  about  how  we'd  outline  Michigan  Molded's  complete  facilities  .  .  . 
small  enough  to  give  your  order  individual  attention  .  .  .  competent  to  do  a  major 
production  job. 

We  hope  the  time  of  dreaming  is  near  an  end  .  .  .  that  we  may  soon  be  able  to  make 
this  solicitation  a  reality. 


]y[lCHIGAN  ]y[()LDED  PlASTICS,  INC. 


DECEMBER  1946 


I'LASTiCS 


DEXTER 
MICHIGAN 

21 


Vinyl  tips  are  shown  being  cut  by  hand  to  the  pattern 

with  leading  members  of  the  shoe  industry ;  a  study  of  com- 
ments in  the  shoe  trade  press;  and  an  analysis  of  plastics 
footwear,  war-time  and  present. 

Plastics  were  only  one  type  of  the  very  great  number  of 
materials  that  rushed  in  during  the  war  to  fill  the  gap  caused 
by  the  leather  shortage.  There  were  rope  soles.  weak-fibered 
plastics,  imitation  leathers,  crude  compositions,  and  several 
other  synthetic  materials.  Some  of  them,  including  a  few 
of  tin-  plastics,  gave  satisfactory  performance,  but  most 
ranged  from  poor  to  abominable. 

The  consumer  complaints  against  them  were  due  not  only 
to  discomfort  and  unsatisfactory  wear  but  also  to  the  ex- 
orbitant prices  often  charged.  The  government  (WPB) 
finally  had  to  intervene  and  establish  a  basic  standard  of 
quality  for  non-rationed  shoes.  In  addition,  the  Bureau  of 
Standards,  trying  to  counteract  these  poor  substitutes,  de- 
vised an  oil  treatment  for  leather  soles  to  increase  their  wear 
25  to  35%.  The  consumer,  getting  more  wear  out  of  his 
leather  shoes,  could  "resist"  the  purchase  of  non-rationed 
slim--,  that  much  longer. 

The  shoe  manufacturers  and  retailers  were  the  target  of 
much  abuse  for  making  and  selling  these  shoes,  which  were 
glutting  the  war-time  market.  Yet  they  had  no  alternative, 
for  all  essential  materials  were  scarce.  Production  of  non- 
rationed  shoes,  the  bulk  of  which  were  composed  in  some 
part  of  synthetic  materials,  was  4.715,000  pairs  in  1942,  36,- 
483.CKHI  pairs  in  1<M3,  and  in  1944  leaped  to  the  phenomenal 
figure  of  69,000,000  pairs,  or  15  times  the  194J  output. 

Most  manufacturers  refused  to  stamp  their  brand  or  com- 
pany name  on  non-rationed  shoes,  which  were  considered  a 
"necessary  evil."  Almost  everything  not  leather  was  classi- 
lied  as  er.tat:.  and  plastics  also  fell  into  this  category  when 
a  good  deal  of  scrap  was  hastily  thrown  into  the  ring  in  a 
reckless  scramble  to  cash  in  on  the  leather  shortage  and  ex- 
c.-cdmgly  heavy  demand  for  shoe-.  Thus  it  was  this  second- 
rat.-  team  of  plastics  in  the  tield  that,  in  the  shoe  industry's 
opinion,  was  representative  of  this  class  i,f  materials. 

Plastics  were  found  acceptable  for  some  |>ar|s  of  the  shoe: 
the  heel,  toe  box.  tongue,  trimmings  and  decorative  fea- 
tures. They  served  practicably  and  helpfully  here.  Hut 
where  most  war-time  plastics  failed  IH-C.III-C  of  the  misuse  of 
scrap  was  in  the  uppers  ami  s,,lc-  of  the  shoes—the  pails 
comprising  about  90%  ot  the  total  materials  used.  Since 
these  parts  would  of  course  comprise  the  bulk  of  the  |HIS( 
war  market  potential  for  any  new  material,  plastic,  had  got 
off  to  a  bad  start. 

Perhaps  the  best  insight  into  the  shoe  industry's  attitude 


toward  footwear  plastics  is  gleaned  from  the  actual  opinions 
of  leading  men  in  every  branch  of  the  industry.  This  writer 
has  had  scores  of  interviews  with  such  men  and  summarizes 
their  thinking  herewith. 

The  shoe  manufacturers  are  almost  unanimously  in  tavor 
of  leather  for  shoes,  whether  in  the  soles,  uppers  or  any 
other  important  portion.  There  is  no  antagonism  toward 
plastics,  only  unconcealed  caution.  One  manufacturer  ex- 
pressed the  feeling  common  to  most:  "Leather  has  proved 
itself.  Plastics  haven't  yet.  Leather  is  a  sure  thing  as  re- 
gards workability,  merchandising,  price,  and  consumer 
satisfaction.  Plastics  aren't — yet.  Kight  now  we're  going 
along  on  the  old  theory  that  a  bird  in  the  hand  is  worth  two 
in  the  hush.  We're  taking  leather  as  first  choice  when  we 
can  get  it.  We're  taking  plastics  only  as  second  choice,  or 
because  we  have  no  alternative.  But  we  all  know  that 
chemistry  can  perform  little  miracles  with  plastics — so 
meanwhile  we're  keeping  an  open,  receptive  and  hopeful 
mind  toward  plastics." 

In  a  poll  of  shoe  manufacturers  and  suppliers  conducted 
by  Hide  rr  Leather  cr  Shoes,  the  question  was  asked  :  "With 
which  of  the  following  materials— plastics,  leather,  and 


Normally,  tip*  are  stamped  out  on  a  "clicking"  machine 


A  perforated  vinyl  tip  Is  machine-sewn  to  leather  vamp 


22 


PLASTICS 


DKCKMIIKK 


synthetics  other  than  plastics — will  there  be  more  experi- 
mental work  in  the  future  than  in  the  past?"  Of  those 
interviewed,  61.5%  thought  there  would  be  more  research 
in  plastics  than  ever  before;  49.5%,  in  leather;  and  45%, 
in  other  synthetics. 

In  another  poll,  the  same  group  was  asked :  "Do  you  be- 
lieve the  following  materials  will  be  increased  or  de- 
creased ?"  The  answers : 

No 
Increased  Decreased  Opinion 

Soles  (%)  (%)  (%) 

Plastics    70.7 26.5 2.8 

Rubber   49.6. . . .'.  .34.5 15.9 

Synthetic  other  than  plastics.  .45.1 44.3 10.6 

Textile  composition 7.1 71.7 21.2 

Rope  7.1 74.3 18.6 

Wood    4.3 79.6 16.1 

Uppers 

Plastics    27.4 46.0 26.6 

Fabric    35.4 45.1 19.5 

As  a  whole  the  manutacturers  are  wary — not  so  much 

with  plastics  for- soles  as  for  uppers.   The  fault  behind  the 


"Lasting"  machine  pulls  edges  of  entire  shoe  over  last 


muddle  and  wariness  lies  largely  with  the  plastics  manufac- 
turers. They  have  been  slow  in  establishing  and  promoting 
reliable  shoe  plastics  by  brand  name.  They  have  failed  to 
familiarize  the  shoe  manufacturer  and  retailer  with  the 
structure  and  composition  of  their  materials,  or  to  present 
factual  and  dependable  data  on  actual  tests.  They  have 
concentrated  on  sales  promotion  based  chiefly  on  the  merits 
of  their  shoe  products  but  concealing  the  shortcomings,  and 
thus  hampering  the  progress  and  acceptance  of  plastics  in 
this  field  by  repeated  disappointments. 

They  have  failed  to  make  a  thorough  study  of  the  re- 
quirements of  a  plastics  for  footwear;  that  is,  they  have 
mistakenly  considered  the  shoe  as  a  static  article  like  a 
toothbrush  or  bridge  lamp,  when  actually  it  is  subject  to 
such  conditions  as  stresses,  abrasions,  flexing,  heat,  cold, 
humidity,  perspiration,  water,  grit,  dyes,  and  acids.  In  short, 
a  shoe  material  must  be  tremendously  adaptable.  This  is  one 
of  the  major  arguments  of  the  leather  men — that  leather,  a 
product  of  hides  and  skins,  is  a  natural  covering  for  the  foot, 
containing  every  essential  feature  of  adaptability  to  the  pe- 
culiar conditions  surrounding  the  foot. 

The  retailers,  who  were  the  principal  target  of  wartime 
consumer  complaints  against  the  many  unsatisfactory  types 
of  non-rationed  footwear,  are  even  more  skeptical  of  the 
"synthetics"  shoe.  Most  strongly  favor  leather  footwear. 
There  is  no  hostility  to  plastics  but,  like  the  shoe  manufac- 
turers, the  retailers  are  waiting  for  plastics  to  prove  them- 
selves, to  come  out  of  the  experimental  stage. 

Consumer  Must  Be  Satisfied 

The  buyer  for  one  national  shoe  retail  chain  stated,  "Our 
business  is  to  sell  shoes,  and  it  makes  no  appreciable  differ- 
ence what  they're  made  of  as  long  as  they  give  full  consumer 
satisfaction.  If  and  when  plastics  can  assure  us  of  this, 
we'll  be  in  the  market  for  plastics  shoes." 

Another  important  chain  store  buyer  said,  "Plastics  have 
some  exceptionally  appealing  assets,  especially  for  women's 
shoes,  in  their  style,  color  and  design  possibilities.  But  we 
can't  jeopardize  comfort,  wear,  workmanship  and  other  es- 
sential shoe  requirements  simply  for  style  values.  If  plastics 
can  give  us  an  all-round  satisfaction,  then  you  can  count  us 
as  a  good  customer." 

The  retailers  feel  an  obvious  and  warrantable  caution 
against  any  repetition  of  war-time  experiences  with  non- 
rationed  shoe  types,  and  thus  hesitate  to  gamble  more  than 
absolutely  necessary  on  unknown  shoe  materials. 

One  prominent  retailer  expressed  an  interesting  and  im- 


Toe  is  given  shape  from  last  by  "toe  wiping"  machine  Tacks  are  removed,  welt  pulled  into  position  for  soles 

DECEMBER  1946  PLASTICS  23 


There  con   be  no  complaints  about  the   lack   of   pliability  of  shoe  tipping  made  of   vinyl.    At   right,   samples   ol 
attractive   nylon   shoes   illustrate   the   adaptability   of   this    popular    plastics    material    to    a    variety    of    styles 


portant  point :  "How  can  we  sell  plastics  shoes  to  customers 
when  the  majority  of  customers  don't  know  anything  about 
plastics  shoes?  They  hesitate  to  buy  a  'cat  in  the  bag." 
They're  sticking  to  brand  names,  and  almost  no  plastics 
shoe  product  has  a  well-known  brand  name.  I  think  one  of 
the  big  jobs  of  the  plastics  people  is  to  sell  the  consumer  on 
plastics  before  selling  us.  When  the  consumer  is  receptive 
to  the  product  and  ready  to  buy,  we'll  be  ready  to  sell." 

He  cited  the  case  of  Neolite  soles  (advertised  as  "not 
rubber,  not  leather,  not  fabric,  not  plastic").  The  Goodyear 
Tire  &  Rubber  Company,  manufacturers  of  Neolite  soles  and 
heels,  have  sponsored  a  nation-wide  consumer  advertising 
campaign,  determined  to  make  Neolite  a  household  word. 
The  advertising  agency  handling  the  account  recently  told 
this  writer  that  this  consumer  approach  had  worked  out 
splendidly.  The  consumer,  having  been  familiarized  with 
the  product,  was  a  receptive  customer  when  the  retailer 
presented  these  shoes  for  sale.  Meanwhile,  other  advertising 
was  directed  to  the  shoe  manufacturer  to  use  these  soles,  and 
to  the  retailers  to  stock  these  shoes — all  based  on  the  ar- 
gument that  the  consumer  was  familiar  with  the  product 
and  hence  did  not  have  to  be  further  educated  and  sold  on  it. 

A  similar  approach  and  promotion  is  needed  for  plastics 
shoe  materials  if  they  are  to  make  more  substantial  and 
rapid  headway  with  the  shoe  retailer.  The  objective  is  to 
make  the  selling  of  plastics  shoes  easier  for  the  retailer. 
Plastics  promotion  should  not  be  left  in  his  hands.  His  job 
is  to  sell  shoes,  not  plastics  or  leather  or  fabrics. 

Value  of  Trodenames 

Brand  names  will  be  of  great  importance.  N'ylon  is  an 
instance  in  point.  The  new  nylon  footwear,  recently  intro- 
duced at  the  Boston  Shoe  Show,  made  an  instant  hit.  The 
word  nylon  is  certain  to  guarantee  ready  consumer  accep- 
tance of  this  brand  of  footwear.  In  fact,  orders  at  the  show 
were  so  heavy  for  nylon  shoe  fabrics  that  the  company  (In- 
ternational Fabrics  Corp.)  had  to  place  all  orders  on  a 
tightly  rationed  basis  after  the  first  day.  Every  member  of 
the  -.hoc  industry  knew  that  because  nylon  was  so  firmly  im- 
planted in  the  consumer  mind  these  shoes  would  practically 
M-ll  themselves. 

Without  the  help  of  brand  nan»c*,  without  informational 
.ti'K  to  manufacturer  and  retailer,  some  plastics  are  never- 
theless making  an  entering  wedge  in  tin-  shoe  market  \- 
a  decorative  veneer  for  women's  heels,  the  demand  runs  into 
many  millions.  For  tipping  and  soles  on  children'^  ~ln«-s. 
the  demand  i*  aKo  great,  for  plastics  tipping  outlasts  thr 
shoe  and  there  are  plastics  soles  which  (ititwr.u  the  leather 
upper*  and  several  pairs  of  rubber  hcrls.  ( >iu-  distributor 


has  orders  for  10,000,000  plastics  soles  for  women's  and 
children's  shoes  for  1946 ;  and  he  can't  take  any  more  orders 
because  that  is  all  of  the  material  he  can  get.  Another  dis- 
tributor expected  to  sell  2,000.000  high  gloss  vinyl  shoe  up- 
pers ("patent  plastic")  in  the  first  quarter  of  1946— his  total 
allocation.  These  are  attractive  figures,  but  they  are  noth- 
ing more  than  an  entering  wedge  in  view  of  the  potentiali- 
ties already  referred  to. 

Assets  and  Liabilities 

Plastics  enter  the  post-war  market  with  .sonic  definite 
assets  and  liabilities.  Their  principal  assets  are  wearing 
qualities,  color  possibilities,  styling  and  design  potentialities, 
variety  of  textures  and  finishes,  and  resistance  to  surface 
abrasion. 

Their  principal  liabilities  at  present,  according  to  shoe  in- 
dustry opinion,  are  lack  of  porosity;  lack  of  essential  plia- 
bility and  flexibility;  inability  to  retain  the  original  shape 
of  the  shoe  under  foot  stresses  and  wear ;  discomfort  to  the 
foot;  softening  under  heat  and  cracking  under  cold  (this 
heat  and  cold  are  the  ordinary  conditions  associated  with  tin- 
foot)  ;  and  workability,  which  means  adaptability  to  factory 
shoemaking  operations  such  as  stitching,  nailing,  cementing, 
tacking,  lasting,  buffing,  hammering,  and  drying. 

Perhaps  no  other  plastics  article  demands  such  special  i/ed 
attention  and  treatment  as  footwear.  The  many  problems 
peculiar  to  footwear  require  a  specific  study  by  any  manu- 
facturer or  supplier  providing  materials  for  the  shoe  in 
dustry.  The  leather  manufacturer  knows  these  problem* 
intimately;  the  manufacturers  of  various  common  shoe  fab- 
rics are  likewise  familiar  with  these  problems;  and  also 
the  manufacturers  of  wood  lasts,  of  chemical  dyes,  and  other 
allied  trades  products.  But  the  average  plastics  manufac- 
turer lias  attempted  to  crash  the  shoe  field  without  an  inti- 
mate knowledge  of  the  special  features  and  qualities  re- 
quired of  his  product.  Because  of  this  unpreparedness  he 
has  been  rebuffed  and  will  continue  to  be  rebuffed  as  long 
as  he  believes  that  no  special  equipment  or  preparedness  is 
necessary  to  make  a  material  used  in  footwear.  At  le.i-t 
one  plastics  materials  manufacturer,  however,  has  taken  a 
step  in  the  right  direction  by  appointing  distributors  with  a 
history  in  shoes  of  over  60  years. 

The  entire  problem  simmers  down  to  this:  at  present. 
plastics'  strong  point*  with  the  shoe  industry  arc  the  fashion 
asjiects:  its  weak  points  are  the  construction  a-|xvts.  The 
obvious  objective,  then,  is  to  overconrc  the  alleged  and  real 
shortcoming* — to  provide  I'la^tic-  which  will  make  the  shoe 
fit  well,  feel  well,  nmmifacturr  well,  and  retain  its  shape. 
•  •nlintifd  OH  f.' 


24 


I)K(  KMHKK  194fi 


MANPOWER 

AT  WORK 

BOOSTS 
PURCHASING  POWER! 


Records  of  the  average  income  of  all  wage-earners 
for  the  past  quarter  century  show  an  increase 
of  150%  in  "real"  hourly  earnings  .  .  .  "real" 
weekly  earnings  nearly  doubled.  Many  industries 
exceed  the  "average".  Industry's  ability  to  create 
better  products  that  improve  living  standards, 
and  industry's  ability  to  pay  higher  wages  and 
higher  taxes,  come  solely  through  increased 
production.  Slow-downs,  or  idleness,  reverse 
the  advances.  Most  people  know,  and  admit, 
these  facts.  Many  need  to  be  reminded  often. 


MOSINEE  paper  technicians  are  helping  manufacturers  improve  their  products  and  production.  Call  MOSINEE. 


MOSINEE 


MOSINEE  •  WISCONSIN 


PAPER 

MILLS 

COMPANY 


DECEMBER  1946 


PLASTICS 


Please  address 

your  letter 

"Attention 

Dept.  8" 


25 


Electric  Brush  Features  Plastics 


"Gyro"  brush  packed  in  a  colorful 
individual  display  carton  of  heavy 
gauge  cellulose  acetate  film.  Hole 
in  case  permits  escape  of  motor 
heat  when  brush  is  in  operation. 
Right,  diversified  plastics  com- 
ponents of  new  electric  hair  brush 


A  LIBERAL  and  intelligent  use  of  plastics  is  illustrated 
in  a  new  powered  electric  hair  brush  now  being  made 
available  by  C.yra.  Inc..  New  York.  This  -brush  of  a  thou- 
sand tinkers."  planned  in  cooperation  with  the  engineering 
staff  of  Shaw  Insulator  Company,  utilizes  molded  and  lami- 
nated phetiolics,  ethyl  cellulose,  cellulose  acetate  butyrate 
and  nylon,  each  of  these  materials  having  been  chosen  for  a 
specific  contribution  to  the  efficiency  and  appearance  of  the 
Imishcd  pnxluct. 

The  brush,  which  weighs  \2y,  07  complete  with  exten- 
sion cord,  produces  a  gentle  scalp  massage.  <  iyratory  mo- 
tion is  ini|)artcd  by  the  motor  to  a  phenolic  plate.  The 
bristle  housing,  clipped  to  this  plate,  receives  this  circular 
impulse  and  transmits  it  to  the  bristle  ends,  which  rotate 
at  high  s|x-cds  varying  with  the  load  on  the  line  supplying 
current  for  the  motor. 

Material  Requirement* 


aal  stability  is  an  outstanding  requirement  in 
the  choice  of  a  material  for  the  housing  and  handle,  since 
(Hissible  variations  of  this  part  induced  by  continued  Use 
uould  ]»•  serious  in  a  mechanism  motivated  by  gyrating  ac- 
tion. The  narrow  space  between  the  brush  cover  and  the 
gyrating  plate  must  IK-  accurately  maintained.  To  meet  this 
requirement,  (fir  on  ethyl  cellulose  was  chosen.  This  ma- 
terial. maroon-colored,  provides,  in  addition  to  the  requisite 
dinK-nsi.iii.il  stability,  an  outer  housing  which  is  attractive. 
warm  to  the  touch  ami  which  possesses  sufficiently  high  im- 
pact strength  to  resist  breakage.  Its  easy  tm.ldability  also 

r  l  lends   it. 

Small  orifices  in  a  raised  section  of  the  back  permit  the 
escape  of  motor  heat. 


Wise  choice  of  outstanding 
properties  of  four  plastics 
materials  are  exemplified 
in  a  new  type  of  hair  brush 


The  gyrating  plate  is  a  compression  molded  phenolic 
chosen  for  its  rigidity,  insulating  properties  and  adaptability 
to  the  inclusion  of  live  threaded  brass  inserts  in  the  molded 
piece.  The  mold  makes  provision  for  two  small  holes  and 
two  grooves  which  seat  the  clips  attaching  the  bristle  hous- 
ing  to  the  gyrating  plate. 

Dimensional  stability  of  a  high  order  is  called  for  in  thU 
plate  since  it  gyrates  in  a  very  small  freeway  and  In-caiisc 
the  plate  directly  receives  the  gyrating  action  set  up  by  the 
motor.  It  must  also  withstand  the  heat  generated  by  the 
motor. 

The  same  is  true  of  the  armature  lx-aring  sup|x>rt.  which 
is  transfer  molded  of  cotton  flock  filled  phenolic.  Here, 
dimensional  stability  bulks  even  larger,  since  it  is  all-im- 
portant that  the  alignment  of  the  rapidly  rotating  motor 
parts  IK-  maintained.  Transfer  molding  was  chosen  In-cau^c 
it  permits  the  part  with  the  necessary  holes  for  mounting 
to  IK-  easily  molded. 

Ill  the  motor  itself.  pa|K-r  base  phenolic  laminates 
as  armature  ends,  ami  a  linen  base  laminate  acts  as  an  in- 
sulating piece  on  the  cam  lever. 

/••in/.-  //  (cellulose  acetate  butyrate  i  was  the  brush- 
maker's  choice  for  the  bristle  housing  block  as  the  plastics 
•litcd  for  the  drilling  and  stapling  operations  of  bristle 
insertion.  In  addition,  the  material's  clarity  and  tians- 
parency  seem  ideally  suited  to  a  sanitary  device.  I  he 
which  is  injection  molded.  ii'<  a  slot  at  each  end 

(Continued  on  page  81 ) 


I'L.iSTl  <  * 


I)K(  KMBKR  1946 


Hes  Safe. . . 


WITH 


^j-ystal-clear  PLEXIGLAS  forms  pro- 
tective guards  that  add  safety  with- 
out lessening  visibility.  These  guards 
eliminate  devices  that  cut  down 
the  visibility  of  the  work,  and  at 
the  same  time  give  the  worker  a 
comfortable  feeling  of  security. 

PLEXIGLAS,  although  exceptionally  strong 
and  sturdy,  is  as  clear  as  the  finest  optical 
glass,  and  this  transparency  is  lasting. 

A  guard  of  PLEXIGLAS  protects  hands 
against  sharp  instruments  and  eyes  from  flying 
particles.  Dirt  is  easily  removed  with  soap  and  water. 

You  can  form  guards  of  PLEXIGLAS  to  meet  your 
specific  needs.  Supplied  in  sheets,  this  acrylic  plastic 
is  easily  shaped  with  simple  tools  in  your  own 
shop.  We'll  be  glad  to  tell  you  how  .  .  . 
or  recommend  a  fabricator  in  your  vicinity. 


Plexiglas 


PLEXIGLAS  is  a  trade  mark, 
Reg.  U.  S.  Pat.  Off. 


Only  Rohm  &  Haas  makes   PI CX  1^1  (IS 
Acrylic  Plastic  Sheets  and  Molding  Powders 


ROHM    &    HAAS    COMPANY 


r/fSH/iVGrOJV    SQUARE.     PHILADELPHIA     S.    PA. 

Mnuftcliiren  gl  Councils  including  PDitics  .     SyniMic  litucucilM       fun|icilts   .   (nirmei       Cninncnit  l»t  me  leather.  Ttitiie.  tiumtlnrt.  Rubber  and  oiher  industries 


I 


Rugged  plastics  radome  efficiently  houses  nose  radar  system  ol  Lockheed  "PV-2" 


Protecting 


Multiplicity  of  ventral  radomes  on  Consolidated  "PB4Y  2" 


Systems 


THE  CHAJ.I.KN'i  IK  of  providing  aircraft  radar  systems 
with  a  protective  housing  of  high  strength,  stringent 
electrical  properties  and  light  weight  has  lieen  successfully 
met  by  the  use  of  radomes  produced  of  low-pressure  lamin- 
ated plastics. 

Kadomes  were  installed  on  many  Army  and  Naval  air- 
craft, utilizing  a  wing,  or  undor-thc-wing  installation  in 
which  the  radome  made  up  hall'  the  covering  of  a  package 
installation.  Some  aircraft  had  dorsal  or  top-side  radomes 
while  others  have  used  ventral  or  In-lly-typo  radomes.  All 
an-  made  in  various  si/es,  with  the  largest  single  section 
ever  molded  constituting  half  a  radome:  the  complete  1.1 
dome  weighed  approximately  4<NI  Id.  was  l.V  long,  8'  wide 
and  3>$'  deep. 

Radome  Design  and  Production  Problems 

A  host  of  itn|Nirtant  requirements  had  to  !*•  met  in  pro- 
ducing a  satisfactory  radome.  Despite  (light  loads,  gun 
Mast,  rocks  thrown  by  the  no-,-  wheel  on  take-off  and 

DEC  KMBKR  1946 


Installing  radar  equipment  in  the  Northrop  "Black  Widow" 

Low  pressure  laminated  radomes 
offer  high  strength,  superior 
electrical  qualities,  lightness 


M  oLaurence 


Lx.  ^rraupt,  ^r. 


even  empty  shell  cases  from  nose  guns,  the  radome  was  to 
remain  intact  and  substantially  undamaged.  Rapid  pro- 
duction methods,  long  life  and  ease  of  replacement  were 
essential.  The  most  important  consideration  was  that  the 
radome  should  offer  a  minimum  of  interference  with  the 
efficiency  of  the  radar  performance. 

A  research  and  development  program  was  instituted  by 
the  Radiation  Laboratory  at  the  Massachusetts  Institute  of 
Technology  and  the  Naval  Aircraft  Factory  in  Philadelphia 
to  examine  new  materials  and  production  techniques. 

From  fabric-covered  wooden  frames  and  molded  plywood, 
the  research  program  progressed  to  special  formulations  of 
the  acrylics,  urea-formaldehyde  laminated  cotton  and  Fiber- 
glas,  alkyd-styrene-copolymer  laminated  Fiberglas,  and  spe- 
cial forms  of  polystyrene  and  low  moisture  absorption  syn- 
thetic fillers.  Thin  laminates  of  alkyd-styrene  resin  and 
Fiberglas  and  polystyrene  fibre  (Polyfibre)  molded  to  a  den- 
sity of  0.9  were  suitable  for  most  small  radomes  housing  10 
cm  radars.  Larger  radomes  required  new  techniques  in 


production  to  withstand  the  higher  stresses,  for  bulkheads 
were  not  feasible  inside  a  radome. 

Thick  sections  of  molded  Polyfibre  were  discarded  be- 
cause of  excessive  weight.  Sandwiches  using  resin  foamed 
between  molded  Fiberglas  faces  in  matching  male  and  fe- 
male molds  had  to  be  eliminated  as  the  ease  of  tooling, 
characteristic  of  the  low-pressure  laminating  process,  was 
lost.  Rubber  foamed  in  place  had  the  same  disadvantage.  Ex- 
panded rubber  boards  used  as  a  core  between  previously 
cured  Fiberglas  skins  were  excellent,  but  for  the  adhesive 
which  adversely  affected  the  electrical  performance. 

A  technique  was  then  devised  to  treat  the  rubber  boards 
with  a  catalyst  wash.  This  made  possible  the  curing  of 
alkyd-styrene  laminates  in  contact  with  the  rubber,  either 
in  a  single  cure,  or  in  several  successive  cures.  Simple 
tooling  was  again  possible,  but  difficulty  was  encountered 
in  maintaining  a  constant  thickness  of  the  rubber  board. 
Oddly  enough,  a  material  developed  for  another  purpose 
proved  to  be  nearly  ideal  for  radome  use.  The  Fiberglas 
honeycomb  sandwich  construction  produced  experimentally 
at  Wright  Field  was  excellent  for  radomes.  It  was  rushed 
into  production  before  V-J  day  but  did  not  reach  combat. 

Electrical  Factors 

The  problem  of  material  and  production  difficulties  was 
complicated  by  the  essential  requirement  of  reducing  to  a 
minimum  the  electrical  interference  of  the  radome.  The 
maximum  range  or  seeing  distance  of  the  radar  system 
would  often  be  greatly  reduced  because  of  only  partial  trans- 
mission of  power  through  the  radome.  Also,  there  were 
angles  at  which  the  radome  prevented  reception  of  signals. 
Incorrect  angular  readings  were  obtained  on  actual  targets, 
and  spurious  signals  were  produced  which  hid  smaller  tar- 
gets. 

The  effect  of  the  introduction  of  material  into  the  radar 
transmission  path  (see  diagram)  shows  the  reduction  in 
power  transmission  which  results  from  the  introduction  of 
various  thicknesses  of  material  having  different  dielectric 
constants.  The  dielectric  constants  of  various  radome  mate- 
rials at  3  cm  are  given  in  the  accompanying  table.  The 
reader  will  notice  that  a  material  having  a  dielectric  con- 
stant of  2  would  have  about  90%  transmission  if  it  were 
%  wavelength  thick  or  if  it  were  J/2  wavelength  thick. 
Radomes  were  made  in  both  thicknesses,  the  %  wavelength 
thickness  corresponding  to  about  0.10"  and  being  used  for 
wing  radomes ;  and  the  */2  wavelength  thickness  correspond- 
ing to  approximately  0.40",  and  in  use  for  nose  radomes. 

(Continued  on  page  86) 
Nose  radome  blends  into  smooth  lines  of  Lockheed  "P-82" 


DECEMBER  1946 


29 


Extruding- 
Acrylics 


Vice-President  and  Research  Director 
PUi  Corporation 


Drop  of  carbon  tetrachloride  causes  almost  immediate  cracking  in  unannealed  acrylic  rod;  annealed  rod  is  unaffected 

Special  techniques  and  equipment  are  required  in  the 
extrusion  of  smooth,  lustrous,  bubble-free  acrylics 


THK  F.X  TRl'SION  of  tin-  acrylic  resins  is  very  similar 
to  tin-  extrusion  of  otlu-r  thermoplastics  except  in  two 
major  respects:  (1)  The  acrylics  at  temperatures  necessary 
to  give  a  good  surface  and  structure  are  prone  to  develop 
bubbles  due  to  the  breakdown  of  the  plastics  into  the  gas 
monomer:  (Jl  They  are  premium  materials  requiring  rela- 
tively high  standards  of  clarity,  color  and  dimensional  tol- 
erance to  justify  their  use  in  major  applications.  Moreover. 
the  extruded  product  must  limit  its  price  hecause  it  corn- 
petr-,  directly  with  the  beautifully  clear  forms  and  sizes  so 
readily  produced  by  the  casting  method.  However,  the  field 


Fig.  1.    Use  of  a  breaker  plat*  and  screens  with  a  short 
die  close  to  end  of  screw  may  result  In  chain  bubble* 


for  extruded  shapes  is  sufficiently  large  ami  attractive  to 
lorm  the  basis  for  a  lucrative  business. 

The  success  of  the  extruder  depends  first  of  all  upon 
obtaining  a  molding  powder  into  which  the  manufacturer 
has  incorporated  the  necessary  ijtiality.  This  is  particularly 
true  in  the  case  of  the  methacrylatcs  In-cau-e  they  mti-t  IK- 
ha/e  free,  very  low  in  color  and  must  give  a  finished  product 
with  a  lustrous  surface. 

Fortunately,  the  manufacturer-  have  performed  excellent- 
ly and  it  is  only  on  rare  occasions  that  ott'-color  or  dirty 
jxiwder  is  received.  However,  decided  differences  do  exi-I 
in  varying  lots.  Some  are  extruded  with  a  glos-icr  -urface 
than  others,  some  are  yellowish-green  while  still  others 
are  yellow  ish-amher.  In  long  pieces,  there  is  alway-  ;i 
tendency  toward-  (Inline--,  a-  compared  to  the  appearance  of 
ca-t  rod. 

Bubble  Trouble 

The  tir-t  -tumbling  block  experienced  by  the  extruder  i- 
bubble  trouble.  The  ordinary  attempt  to  eliminate  the  diffi- 
culty by  drying  the  molding  powder  i-  rarely  successful. 
Attempts  to  eliminate  hubbies  by  dropping  the  temperature 
rail-e  -o  much  back  pre--nre  that  most  extruders  will  not 
pull  the  load.  The  u-e  of  a  breaker  plate  ami  sen-en-  with 
a  short  die  close  to  the  end  of  the  -crew  i-  likely  to  result 
ri  chain  bubbles  such  a-  shown  in  Fig.  1.  The  bubble- 
apparently  form  at  the  end-  of  the  grid  hctwcen  the  hole- 


30 


I'l.ASTi  fS 


DECEMBER  194fi 


O   0s."  ~& 


THE    VAN     DORN     IRON    WORKS    CO 


DECEMBER  1946 


31 


PRESSURE  P 

MAY  BE  ATTACHED 


F~CS 


F=TTR2P 


(1)  Jacketed  pressure  chamber 

(2)  Stuffing  box 

(3)  Adjustable  hold-back 


Fig.  2.  Auxiliary  pressure  chamber  to  inhibit  bubbles. 
Friction  of  3  plus  2  must  balance  "F."  or  the  plastics 
will  either  stretch  and  be  blown  out.  or  it  will  pile  up 


END  ZONE 


Fig.  3.    The  pressure  drop  and  flow  procedure  of  heavily 
filled  materials  as  they  go  through  a  cylindrical  die 

in  the  breaker  plate  where  pressure  is  low  due  to  the  short 
die,  and  where  there  are  regions  of  slow  movement  of  ma- 
terial Ix-tween  the  holes  in  the  breaker  plate.  Streamlining 
the  breaker  plate  helps  but  will  not  entirely  eliminate  the 
trouble.  A  long  die  gives  a  higher  back  pressure  on  the 
breaker  plate;  this  will  eliminate  hubbies  at  the  die  but 
they  may  reappear  some  distance  from  the  die,  although 
more  generally  distributed  throughout  the  extrusion  and 
with  less  of  the  chain  effect  apparent. 

\  -oon  as  the  acrylic  leaves  the  die  one  can  observe  the 
usual  formation  of  bubbles.  Kxccpt  in  very  thin  sections, 
cooling  of  the  plastics  will  not  stop  or  delay  the  formation 
of  the  bubbles.  It  has  been  observed  that  a  definite  time  is 
required  for  the  bubbles  to  form.  The  time  is  much  longcr 
for  a  low  tcni|>crature,  stiff  material  than  it  is  for  a  hotter 
one.  It  is  doubtless  influenced  by  the  viscosity  of  the  plas- 
tics, but  there  are  other  factors  also.  Th,.  gas  is  dissolved 


o  o 


Fig.  4.  Diagram  of  an  extrusion  molding  die  showing  vac- 
uum bubbles  and  flow  lines,  due  to  shrinkage.  It  is  dif- 
ficult to  prevent  a  lew  vacuum  bubbles  forming  near  sprue 


32 


in  the  plastics  at  high  pressure  and  is  in  this  state  similar 
to  the  dissolved  crystals  in  an  undercooled  liquid.  A  break 
in  the  structure  must  be  present  before  the  gas  phase  can 
separate  out  in  the  form  of  bubbles.  A  minute  speck  of 
foreign  matter  can  offer  such  a  break  and  hence  dirt  in  the. 
powder  can  start  bubbles.  Moreover,  just  as  stirring  an 
undercooled  liquid  will  cause  instant  crystal  formation,  the 
friction  along  the  surfaces  of  the  breaker  plate  will  cause 
the  instant  formation  of  bubbles  on  the  back  of  the  breaker 
plate  under  low  pressure  conditions  as  in  Fig.  1.  It  is 
apparent  then  that  both  the  machine  setup  and  the  powder 
itself  are  factors  in  the  formation  of  bubbles. 

Some  years  ago,  the  Plax  laboratories  investigated  the 
time-temperature  characteristics  of  bubbling  in  several  kinds 
of  methacrylate.  A  rod  of  bubble-free  extruded  material 
was  placed  in  a  controlled  temperature  bath  and  held  at 
various  temperatures.  Both  the  bath  and  the  container  were 
transparent  so  that  the  specimen  was  clearly  visible.  Results 
reveal  that  several  minutes  are  required  for  bubbles  to  form 
at  the  lowest  practicable  extrusion  temperatures. 

A  similar  set  of  observations  under  superimposed  pres- 
sures indicated  that  a  constant  pressure  of  merely  20  psi 
on  the  hot  plastics  would  prevent  bubble  formations.  It 
would  seemingly  be  simple  to  extrude  into  a  back  pressure 
chamber  but  actual  experience  dictated  otherwise — 1 
shows  such  a  chamber  which  may  be  filled  with  liquid  or 
gas  and  has  a  right  hand  end  attached  directly  to  the  die. 
Because  the  plastics  is  soft,  pressure  P  sets  up  a  hydrostatic 
pressure  in  all  directions  within  the  plastics  as  shown  by 
the  little  cube  of  material.  At  each  end  of  the  chamber, 
the  material  passes  through  a  stuffing  box  or  its  equivalent 
into  a  region  of  atmospheric  pressure.  The  force  F  acting 
on  the  rod  would  be  vR2P  where  ir/?2  is  the  area  of  the  rod. 
If  the  right  end  is  connected  to  the  die,  the  plastics  will  be 
forced  into  the  extruder,  but  the  friction  of  the  stuffing 
box  2  and  holdback  3  must  exactly  equal  /•'  or  the  rod  will 
either  stretch  and  be  blown  out  or  will  refuse  to  move  and 
pile  up  inside  the  chamber. 

The  back  pressure  chamber  was  superseded  by  the  Plax 
Lubofilm  method  which  will  be  described  later. 


Direct  Extrusion 

It  is  admitted  that  plastics  are  rhcological  materials  and 
that  they  do  not  follow  the  simple  laws  of  viscous  flow. 
Nevertheless,  the  departure  from  truly  viscous  flow  is  not 
so  great  but  that  some  interesting  conclusions  can  be  drawn 
from  assumptions  l>ased  on  viscous  flow.  These  lead  to  the 
conclusion  that  the  flow  through  a  simple  smooth  tube  or 
die  is  something  like  that  shown  in  Fig.  3.  Here,  the 
flow  takes  place  from  left  to  right.  At,  and  near,  the  left 
hand  end,  the  hydrostatic  pressure  P,  is  so  great  that  the 
material  is  locked  against  the  wall  and  cannot  slip.  Move- 
ment must  take  place  by  shear  within  the  material  and  a 
line  of  molecules  along  the  line  of  P,  at  a  certain  instant 
would  move  to  the  right  and  sometime  later  have  the  para- 
bolic shape  as  indicated.  Nearer  the  exit  of  the  die.  at  /',. 
the  friction  against  the  die  is  reduced  to  such  an  extent  that 
some  slip|>age  IK-CUTS  which  reduces  the  severity  of  the  para- 
Ixilic  flow  as  here  shown.  Very  near  the  die  at  /'.  an 
anomalous  region  of  instability  results  so  that  heavily  filled 
materials  are  likely  to  develop  a  pattern  of  cracks.  I  lu-sc 
cracks  are  susceptible  even  in  such  plastics  as  jxilystyrene 
and  acetate  and  to  a  lesser  extent  in  the  mcthacrylatcs.  In 
most  plastics  they  cause  a  line  matte  surface,  obvious  in 
jHilyslyrene  when  extruded  at  a  low  tcnijK-ratiirc  and  present 
as  a  smoky  dulling  of  the  surface  in  methariylatcs  when  ex- 
truded at  a  very  low  tcni|>crature.  The  dulling  remains  on 
the  surface  if  the  plastics  is  rapidly  cooled  near  the  dir  but 
the  surface  will  clarify  a  slmrt  distance  after  leaving  the  die 
if  the  surface  is  allowed  to  -\;\\  hot. 


DECEMRKK  1946 


REHEATER  SECTION 
USED  HERE  IF  ROD 
IS  TO  BE  DRAWN  DOWN 


WATER  COOLED 
HOPPER  SECTION 


AUTOMATIC 
KNIFE 


1\       PRESSURE  GAGE 
SAFETY    STOP 


Fig.  5.  The  Plax  Lubofilm  process  of  continuous  extrusion,  which  has  been  working  successfully.  Bub- 
bling cannot  occur  in  the  die  because  of  the  high  back  pressure  while  the  plastics  material  is  in  it. 


.The  effect  of  high  rates  of  extrusion  is  to  cause  an  ap- 
parent drop  in  the  viscosity  of  the  plastics.  The  combined 
results  of  the  flow  and  the  viscosity  changes  tend  to  make 
the  material  puff  up.  Both  polystyrene  and  the  extrusion 
grades  of  methacrylate  show  this  effect  very  decidely,  where- 
as such  plastics  as  highly  filled  materials  and  Styraloy  show 
it  to  a  far  lesser  extent.  The  phenomenon  of  puffing-up 
is  particularly  troublesome  when  dies  are  designed  for  heavy 
section  complicated  shapes. 

There  are  three  divisions  of  extrusion :  the  direct  or  co- 
ordinated method,  the  semi-positive  and  the  positive  method. 

In  the  direct  method,  it  is  necessary  to  design  a  die  to 
give  the  proper  shape ;  then  to  co-ordinate  the  speed  of  the 
extrusion,  the  speed  of  the  take  off  device,  to  control  the 
cooling  (to  prevent  warping)  and  to  provide  innumerable 
gadgets  to  prevent  the  extrusion  from  sagging  out  of  shape. 

In  the  semi-positive  method  the  most  important  surface 
or  surfaces  is  controlled  by  a  mold.  Typical  examples  are 
the  blowing  process  where  the  outer  surface  is  controlled 
by  a  mold  and  the  tube  sizer  method  of  extruding  tubing. 
In  both  cases,  any  variations  affect  only  the  wall  thickness. 

The  positive  method  is  one  in  which  all  surfaces  are  con- 
trolled by  some  sort  of  mold  with  the  resulting  part  always 
an  exact  replica  of  the  mold.  Variations  may  result  in  some 
rejects  but  it  is  not  necessary  to  co-ordinate  a  varied  assort- 
ment of  apparatus  to  produce  a  good  part.  Typical  examples 
are  injection  molding,  transfer  molding  and  extrusion  mold- 
ing. 

Positive  Methods  of  Extrusion 

EXTRUSION  MOLDING:  This  method  utilizes  a  mold  to 
give  the  desired  shape.  It  is  useful  primarily  to  produce 
very  large  pieces  which  may  be  either  complicated  or  simple. 
If  the  piece  is  large,  it  is  usually  necessary  to  heat-cycle  the 
mold  in  order  to  eliminate  flow  lines.  Large  pieces  require 
20  to  30  min.  to  fill  the  mold  and  a  back  pressure  of  inert 
gas  at  a  medium  pressure  is  necessary  to  prevent  excessive 
bubbling.  The  mold,  when  full,  must  be  cooled  from  the 
farthest  end  away  from  the  sprue  and  the  gate  must  be  kept 
hot  so  that  the  shrinkage  can  be  taken  up  by  fresh  hot  mate- 
(Continitcd  on  page  66) 


PLASTICS  INLET 


Die 


Fig.  6.    A  system  of  cooling  plastics  under  pressure,  in 
order  to  achieve  a  heavy  extrusion  which  is  bubble-free 


(AB)  Force  supplied  by  motor 

(BC)  Force  required  to  move  plastics 


(1)  Stationary  nozzle 

(2)  Oscillating  lubricated  slipper  plates 

(3)  Guides 

(4)  Continuously  extruded  plastics 

(5)  Stationary  side  plates 


Fig.  7.     The  Plax  Slipper  Die  method  is  useful  in  extrud- 
ing methyl  methacrylate  slab  stock  or  rectangular  shapes 


DECEMBER  1946 


PLASTICS 


33 


B 


SIDE 


Fig.  1.     Suggested  construction  of  device  (or  evaluating  tendency  of  plastics  film  to  deform  under  heat  and  pressure 

End-Use  Testing  of  Plastics  Films 

There  is  acute  need  to  standardize  testing  of  end  products; 
various  types  of  equipment  are  suggested  for  this  purpose 

Welter 


THE  NEED  for  standard  toting  procedure  based  <>n 
end-use  of  plastic*,  film  and  sheeting  commonly  used 
for  shoes,  handbags,  upholstery  matt-rials  and  shower  cur- 
tains is  acute  to-day;  particularly  when  an  unfavorable  sup- 
ply-demand ratio  encourages  the  sale  of  inferior  materials 
with  little,  or  no  responsibility,  for  quality  assumed  by  the 
sheet  material  manufacturer  and  the  fabricator. 

Visual  itis]K-ction  of  plastics  sheeting  can  do  little  more 
than  establish  surface  quality,  which  has  Ix-en  surprisingly 
uniform.  A  reasonably  acute  sense  of  smell  will  readily 
detect  the  presence  of  those  plastici/ers  which  will  render 
it  objectionable.  Hut  visual  and  olfactory  in-|H-ction  cannot 
prophesy  whether  the  sheeting  will  IK-  returned  to  the  mer- 
chandiser by  an  irate  customer  whose  handbag  or  shoe- 
ha\e  sjilit.  melted  or  failed,  t'nhappily.  in  such  cases,  the 
fabricator  is  not  equipjied  to  determine  the  source  of  trouble. 

These  failures  can  only  IK-  detected  by  laboratory  tests 
based  on  conditions  encountered  in  actual  use— conditions 
under  which  the  failure  actually  occurred. 

The  present  uncertain  quality  of  many  plastics  sheeting 
and  lilm  cannot  IK-  permitted  to  exist  for  much  longer  with- 
out serious  consequences  to  l>oth  merchandiser  and 
rials  manufacturers.  The  responsibility  for  quality  control 
of  such  materials  should.  jK-rbaps.  rest  laigely  with  the  large 
materials  manufacluiet  s  themselves — The  Hakelite  ' 


Fig.  2.     Flexing  device  consist*  ol  members  that 
pet  mil  constant  flexing  ol  sample  without  stretch 


. 
(«r  Ihr  Ki.hrr 


MiTK      I  hi.  .tmlT  wa»  mwfc  bir  th»  author  umUr  Ihc  »u»| 
Pmnrr  I  ••.  (""«  .hirh  h»  recrnlly  tr.iBi»-,|  i.,  ir.tmir  Im  lanrc  cnn.ult- 


!•  I.  \STtCS 


DECKMBKR  1946 


MAKES  POSSIBLE  THIS  NEW  DEVELOPMENT  IN  SILVER  CHEST  DESIGN 


Vt  A  sparkling  new  note  in  home  decoration  is  the  distinctive 

Marshall- White  Silverware  Chest  of  Plaskon  Molded  Color  .  .  . 

high  in  utility  value  .  .  .  beautiful  as  polished  ivory,  and  very 

complementary  to  the  most  distinguished  silver  service. 

Here  again  is  an  excellent  example  of  the  versatility  of  Plaskon 

plastics.  In  no  other  type  of  material  would  it  have  been  possible 

to  secure  such  glowing  color  .  .  .  such  freedom  of  design  .  .  .  such 

low  mass  production  costs. 

Plaskon  can  be  molded  into  almost  any  practical  shape  or  size  of 

product.  The  clear,  brilliant  tones  of  Plaskon  offer  wide  oppor- 


PLASKON 


tunities  for  specialized  product  design  in  both  the  consumer  and 
industrial  fields. 

Plaskon  colors  are  uniform  and  unchanging,  because  they  are 
solid,  permanent  color  through  and  through.  The  hard,  non- 
porous  surface  of  molded  Plaskon  will  not  tarnish,  check  or 
corrode.  It  remains  warmly  glowing  through  the  years  .  .  .  can 
be  washed  as  often  as  desired  ...  is  strong  and  shock-resistant. 
There  is  an  extremely  wide  range  of  advantages  in  Plaskon*  urea- 
formaldehyde  and  melamine-formaldehyde  plastics,  making  them 
highly  adaptable  to  many  requirements.  Write  for  illustrated  book. 

•Trade  Mark  Reg.  U.S.A. 

PLASKON  DIVISION  •  LIBBEY  •  OWENS  •  FORD  GLASS  COMPANY 

2106  Sylvan  Ave.,  Toledo,  Ohio  •  In  Canada:  Canadian  Industries,  ltd.,  Montreal,  P.O. 


N 


v 


RESERVE  SPACE  NOW  FOR  MARCH  DIRECTORY  ISSUE 


At   NO  EXTRA  COST  to  Advertisers 


Over  14,000  Key  Men  in  Plastics 


And  now  it's  the  Third  Annual  Plastics 
Directory — brought  completely  up-to-date — 
more  than  ever  the  ha-ic.  v  ear-round  l.u\in- 
guide  for  the  entire  plastics  industry. 

Again,  Plastics  Annual  Directory  will  he, 
published  as  the  March  issue  of  Pla>lics. 
It  will  he  received  by  Plastics  total  circula- 
tion of  1  1,873,  of  which  13.2  !.*>  is  net  paid 
\IU!  .  .  .  a  circulation  concentrated  on  key 

men   in    the   pla.-lics 
industry   and   in    12 


end-Ming  industries  .  .  .a  circulation  which 
is  a  direct  influence  on  specifications  and 
purchases  in  this  faslest-grow  ing  field.  \gain. 
this  12-inonths  assured  readership  is  avail- 
ahle  to  Plastics  advertisers  nt  no  t:\lrn  ro>f. 

Be  sure  of  an  till-hnwr  audience  for  your 
advertising — //•»•  must  iinftorlnnl  IIH-H  in  />/»i>- 
licx — hy  being  sure  to  reserve  space  in  I'l.i-- 
lie- Third  \nniial  Directory  NOW.  Rcscrm- 

i*  r/osc  l-'i-lirimrv  I. 


A     ZIP  F.DAVIS    #    PUBLICATION 

I8.">  V  \\.il..i-li   \\riiui-.  <  Im  .1^.1  I.  HIiiKii- 

Ni  i.     Y"rk        •        \\.l-lllll^tnll        «        I  .11-      \llp-lr-       «        I  olli|..|l       .         I.. I. .III.. 


PLYING- PLASTICS  -RADIO  NEWS  .RADIO-ELECTRONIC  ENGINEERING  .  POPULAR   PHOTOGRAPHY 


FOLD  LINE 


F 

*            B 

f 

E 

- 

Wf  1 

I 

D 

I       : 

OP£N 


CLOSED 


Fig.  3.    A  method  of  standard  sample  preparation,  and  fold- 
ing action  of  the  sample  in  the  machine  during  operation 

The  B.  F.  Goodrich  Chemical  Co.,  U.  S.  Rubber,  Firestone, 
etc.,  but  except  in  one  case  these  manufacturers  do  not  con- 
vert the  plastics  resin  (vinyl)  into  sheeting,  and  hence  have 
little  control  over  the  composition  of  the  finished  product. 
True,  most  of  them  issue  printed  instructions  which  are  often 
ignored  and  they  also  carefully  check  their  resins  in  their 
own  laboratories,  but  such  tests  have  relatively  little  relation 
to  end-use.  The  values  obtained  are  not,  it  is  here  claimed, 
a  reliable  indication  of  how  the  materials  will  perform  in  the 
hands  of  the  average  consumer.  This  leaves  the  merchan- 
diser in  the  situation  where  he  can  look  only  to  himself  for 
help  in  establishing  the  quality  of  those  plastics  materials 
he  has  on  his  shelves. 

Manufacturers  Should  Be  Informed 

Even  accurate  information  obtained  from  end-use  testing 
can  be  of  slight  value  unless  it  is  brought  to  the  attention  of 
materials  manufacturers  and  fabricators  alike,  so  that  de- 
sirable qualities  may  be  improved  and  shortcomings  elimi- 
nated. The  materials  manufacturer  knows  little  of  the  mer- 
chandiser's "returned-goods"  department,  but  it  is  there  that 
his  serious  attention  should  be  directed.  The  performance 
of  plastics  sheeting  today  will  determine  whether  it  has  won 
a  permanent  place  in  industry  or  whether  it  will  be  brusquely 
pushed  aside  in  favor  of  leather  when  the  supply  once  again 
becomes  plentiful. 

For  the  reasons  discussed  above  and  for  many  others  too 
involved  for  discussion  here,  it  is  proposed  that  simple  equip- 
ment be  devised  that  will  duplicate  as  closely  as  possible  con- 
ditions encountered  in  actual  use  that  are  responsible  for 
failures.  Such  equipment  should  be  utilized  to  evaluate  suit- 
able samples  used  in  the  manufacture  of  over-the-counter 
merchandise,  and  each  sample  graded  against  a  standard  that 


niu>t  lie  established  experimentally.  Both  fabricator  and 
manufacturer  should  be  acquainted  with  these  results.  The 
proposed  equipment  does  not  now  exist,  as  far  as  is  known, 
for  the  reason  that  end-use  testing  has  not  been  sufficiently 
emphasized,  but  it  can  be  basically  simple.  The  purpose  of 
this  report  is  to  urge  that  the  plastics  industry's  interest  be 
aroused  in  pursuing  the  aims  discussed  herein.  Here,  in 
short,  is  an  opportunity  to  set  up  improved  standards,  de- 
signed to  bear  directly  upon  merchandising. 

End-Use  Tests 

An  examination  of  plastics  handbags  and  shoes  in  "re- 
turned goods"  discloses  that  the  most  common  reasons  for 
rejection  in  order  of  approximate  frequency  are  as  follows: 

( 1 )  Deformation  under  heat  and  pressure. 

(2)  Offsetting — transfer  of  stains  from  varnishes,  lac- 
quers, printing  inks,  etc.,  as  the  result  of  long  contact. 

(3)  Plasticizer  migration — softening  of  furniture  finishes 
after  prolonged  contact. 

(4)  Discoloration,  yellowing  and  ageing  resulting  from 
improper  compounding,  and  observed  only  in  the  light  col- 
ored patents. 

(5)  Cracking — resulting  from  sudden  extreme  tempera- 
ture variations. 

Besides  the  above  noted  reasons  for  rejection,  there  are 
other  tendencies  that  should  be  carefully  examined.  It  is 
suggested  that  standards  of  tensile  strength,  flammability, 
elastic  recovery,  and  seam  strength  be  established.  Follow- 
ing is  a  detailed  discussion  of  reasons  for  rejections  found 
in  "returned-goods"  together  with  drawings  and  descrip- 
tions of  devices  for  testing  that  may  prove  useful  in  evaluat- 
ing plastics  film  and  sheet  destined  for  consumer  products. 

(Continued  on  page  83) 


Fig.  4.    A  box  with  insulated  walls,  in  which  the  test- 
ing device  (Fig.  1)  is  placed  during  testing  procedure 


DECEMBER  1946 


PLASTiCS 


37 


An  assortment  of  typical  parti  which  must  be  molded  to  clo*e  precision  tolerances 


INDUSTRY  today  is  turning  more  to  phenolic  molded 
parts  in  all  types  of  instruments.  Whether  it  be  a  simple 
thermostat  or  a  complicated  control  device,  some  of  the  most 
essential  parts  are  often  molded  from  the  phenol  formalde- 
hydes. It  appear-,  that  the  trend  is  more  and  more  toward 
these  materials.  However,  one  obstacle  retarding  an  even 
greater  use  of  phenolics  is  that  it  is  difficult  to  hold  dimen- 
sional tolerances  found  practical  in  metals. 

For  many  years  the  custom  molder  offered  his  molding 
facilities  to  every  one.  His  was  a  very  competitive  field 
and  so  he  had  little  opportunity  to  spend  time  and  money  in 
research  on  molding  to  close  tolerances.  Certain  standard-. 


The  "M  10"  periscope  head,  illustrating  close  align- 
ment ol  parts  necessitating  close  molding  tolerances 


Precision 


Chief  Process  Engineer 
Minneapolis-Honeywell   Regulator  Company 


have  been  established  for  the  plastics  industry  as  practical] 
tolerances  for  phenolics.  We  definitely  agree  with  these' 
.standards. 

There  is  a  small  ]>erc-entagi-  of  parts  which  fall  into  a  soine- 
uhat  different  category  than  average  molding.  These  are 
parts  which  are  plentifully  evident  in  the  instrument  and  o,n- 
trol  field.  The  design  engineer  knows  that  if  he  wen-  .ilile 
to  hold  certain  tolerances  mi  the  plastics  parts  he  might  be 
able  to  save  a  considerable  cost  in  the  instrument.  Tin-  is 
the  type  of  molding  we  should  like  to  discuss.  It  has  been 
proved  that  when  I'ound  necessary,  cnmentional  tolerances 
of  ±  .003  per  in.  rotild  K-  cut  to  ±  .0015  per  in.,  and  these 
dimension-,  maintained  under  normal  conditions. 

We  feel  that  precision  molding  is  going  to  be  a  very  im- 
IM.rtant  |>art  of  the  plastic-  industry,  and  we  know  that  a 
KH-.it  deal  of  research  has  IK-CII  done  on  this  subject  during  i 
the  last   lew   year-.     Many  large  concerns  doing  their  own  I 
molding  are  demanding  closer  tolerances,  hut  the  advantages 
gained  by  this  increased  precision  must  l>c  carefully  bal- 
anced against  the  increased  cost  of  molded  parts. 

NOTE:  Thi"  article  ii  haned  on  a  paper  prorated  at  the  annual  mertinl  I 
of  the  American  Society  ol  Mechanical  Kniinecri. 


.18 


IQlfi 


Many  elements  enter  into  so-called  precision  molding. 
Strangely  enough,  a  deeply-rooted  tendency  on  the  designer's 
part  is  that  he  specifies  as  much  tolerance  as  possible  on  all 
dimensions.  He  should  use  fractional  dimensions  wherever 
possible  and  put  close  tolerances  only  where  they  are  abso- 
lutely required.  Holding  dimensions  to  ±.0015  per  in.  on  a 
few  dimensions  is  not  too  difficult. 

Accurate  Mold  Dimensions 

Another  important  criterion  is  that  the  mold  be  as  accu- 
rate as  a  good  moldmaker  can  make  it.  To  get  a  12  to  16 
cavity  production  mold  to  print  on  all  dimensions  is  not  very 
easily  done  even  with  tolerances  of  ±  .005"  on  mold  draw- 
ings. Cut  a  few  of  these  mold  tolerances  to  ±  .002"  and  the 
mold  cost  may  readily  double.  Considering  that  some  molds 
may  have  30  to  40  dimensions  to  hold  in  each  cavity  one 
realizes  that  chances  of  getting  correct  dimensions  on  all 
cavities  are  very  slim. 

From  our  own  experience  we  have  found  very  few  multi- 
ple cavity  molds  that  can  be  made  to  pass  on  every  dimen- 
sion. For  this  reason  we  have  gone  to  a  smaller  number  of 
cavities  where  we  have  to  hold  close  tolerances  on  the  parts. 
To  make  2  or  4  cavities  correct  is  very  possible.  The  mold- 
ing cost  goes  way  up,  but  this  can  usually  be  justified  by  the 
advantage  of  closer  dimensions. 

The  uniformity  of  bulk  factor  and  moisture  content  is  very 
important.  That  is,  uniformity  throughout  the  batch  and 
also  from  batch  to  batch.  If  mold  dimensions  are  correct  and 
material  uniform,  we  find  that  we  can  vary  the  density  and 
dimensions  of  castings  considerably,  both  in  compression  and 
transfer  type  molds.  Various  other  elements  also  enter  into 
this  type  of  molding,  such  as  preheating  of  powder,  mold 
temperature,  time.  etc. 

Post  conditioning  of  molded  parts  is  being  utilized  when 


Mold  for  "M-4"  periscope  head  is  of  laminated  construction 

These  molds  were  actually  made  to  lamination  die  toler- 
ances. The  clearance  between  force  and  cavity,  the  flash 
escapes,  landings  etc.,  were  held  to  ±.001"  and  everything 
was  polished  to  a  mirror  finish.  The  cost  of  this  work  may 
seem  quite  unnecessary  but  we  know  now  that  this  made  it 
possible  for  us  to  do  the  job.  The  theory  was  that  the  back 
pressure  of  the  mold  was  determined  by  the  fit  around  the 
force  and  flash  escapes.  If  some  cavities  did  permit  mate- 
rial to  escape  more  freely  than  others  the  back  pressure 
varied,  thus  also  varying  the  density  of  the  casting  and  the 
shrinkage.  (Continued  on  page  81) 


Molding  Phenolics 

Mold  construction,  moisture  content  and  uniformity  of  materials, 
and  preheating,  are  some  factors  requiring  careful  consideration 


some  extreme  dimension  must  be  held.    This  amounts  to 
after-baking  of  parts  so  after  shrinkage  is  accelerated. 

We  would  like  to  illustrate  the  procedure  that  was  used 
to  control  dimensions  on  the  M4  and  M10  periscope  heads. 
We  lived  with  these  moldings  for  several  years,  and  had  a 
chance  to  find  out  what  it  was  possible  to  do.  The  M4  head 
was  6.437"  (+.000;  —.010)  long.  It  had  14,  4X36  holes 
cast  in  it.  The  holes  had  a  tolerance  of  ±.003"  on  1.437  cen- 
ters. This  tolerance  was  required  as  the  plastics  part  had  to 
match  the  countersunk  holes  on  a  stamped  window  frame. 
This  tolerance  would  not  usually  worry  anyone,  but  we 
found  ourselves  in  need  of  12,  4-cavity  molds.  To  make  48 
identical  compression  cavities  with  an  overall  tolerance  of 
(+.000;  - — .010)  on  a  6.437"  dimension,  meant  very  ac- 
curate workmanship.  The  only  way  we  could  see  any  chance 
of  holding  the  mold  dimensions  to  within  the  limits  required, 
was  to  go  to  the  laminated  type  of  mold  construction.  This 
permitted  us  to  grind  almost  everything  after  hardening. 
The  worst  problem  was  when  the  hole  to  hole  distance 
changed  in  hardening,  using  up  almost  the  whole  part  toler- 
ance in  the  mold.  We  were  forced  to  leave  holes  undersize 
and  jig  bore  them  with  carbaloy  tools  after  hardening. 


Two-cavity  "M-10"  periscope  head  mold  in  the  press.    Shape 
of  this  part  was  such  that  transfer  molding  was  necessary 


DECEMBER  1946 


39 


From  the  outset.  F.dward  Heck,  chief  engineer  of  tlie 
Sinkn  Manufacturing  and  Tool  Co..  the  molders.  and  Rich- 
ard \\Yavrr.  Mi|KTvising  tool  engineer  of  Hallicraitcrs.  were 
aware  of  an  exacting  task  requiring  the  molding  of  compli- 
cated sections  of  several  half  spheres,  cones  and  triangles. 
And.  most  difficult  of  all,  the  upper  half  of  the  section  had 
to  contain  a  transparency,  perfect  in  quality,  for  indicator 
and  dial  face  which  necessitated  the  elimination  of  material 
flow  stresses. 

Alter  a  series  of  tests,  it  was  decided  that  the  escutcheon 
l>e  made  of  an  injection  molded  methyl  methacrylate.  Km- 
ploying  a  mold  with  a  highly  polished  top  section  for  the 
transparent  portion  of  the  piece,  Heck  used  a  center  shot 
without  a  cold  slug,  thereby  eliminating  the  material  stn -s> 
lines  and  a  costly  trimming  jol>.  Karly  experimentation  re- 
vealed, however,  that  a  fast  molding  cycle  of  45  sec  caused 
a  warping  in  the  center  of  the  section.  On  the  other  hand. 
the  machine  would  not  eject  the  piece  at  a  sl,,u  cycle  of 
\l/i  min. 

Arbor  Press  Holds  Shape 

The  piece  was  molded  successfully  after  Heck  struck  upon 
the  solution  of  molding  it  in  a  one  cavity  mold,  with  Kith 
mold  sections  water-cooled,  at  a  temp  of  160°  F.  The 
material  temp  was  held  closely  to  420°  F.  Using  a  molding 
cycle  of  one  min,  the  piece  was  ejected  and  the  sprue  removed 
from  the  piece  part  as  closely  as  possible.  The  piece  was 
then  placed,  face  down,  on  a  water-cooled  contour  plate  in 
an  arbor  press.  Pressure  was  applied  to  the  terminal  of 
the  sprue  to  insure  the  molding's  remaining  flat  during  th? 
cooling  cycle.  One  piece  was  molded  at  a  time. 
(Continued  on  f°9e  88) 


Molded   main  tuning  dial  escutcheon  of  Hallicrafteri  radio 
model.     Lett,  escutcheon  with  sprue  at  it  comet  from  press 


Unusual  Molding  Creates 
Radio  Dial 


CorlSi 


•imonSon 


FKKKDOM  of  design  through  plastics  is  playing  an  in- 
creasingly important  role  in  post-war  expansion  and 
development  of  the  radio  manufacturing  field.  This  trend, 
prevalent  for  some  time  in  the  manufacturing  of  home  re- 
ceivers, is  rapidly  gaining  followers  in  the  field  of  high 
frequency  radio  equipment. 

The  llallicrafters  Company  of  Chicago,  manufacturer  of 
high  frequency  communications  receivers,  is  today  making 
generous  use  of  various  plastic-  materials  in  its  entire  line 
of  jH.st -war  reccix. 

One  |>»st  war  radio,  llallicrafters  Model  S  .V  /.'.  ami  one 
of  its  parts  in  particular,  the  main  tuning  dial  escutcheon, 
provided  plastics  \\itli  an  Opportunity  to  reveal  its  remark- 
able adaptability.  Although  the  development  of  this  es 
cutcheon  posed  several  problems  the  I  lallicrafters'  engin- 
eers are  in  agreement  that  the  Use  of  plastics  offered  the  only 
solution  from  the  standpoint  of  production  cost  and  the  sim- 
plicity of  handling  a  one-piece  section  on  the  assembly  line. 
Preliminary  to  production  it  was  discovered  in  comparative 
cost  studies  that  the  handling  of  a  two-piece  unit,  con 
-tructril  of  glass  and  metal,  was  considerably  higher  than 
the  one-pi-  >i..n. 


40 


Dial  escutcheon  is  placed  in  water-cooled  contour  plate 
ol  arbor  press  to  retain  Its  shape  during  cooling  cycle 


DECEMBER 


General  Chemical  Fluorine  Research  Presents-- 


THE  CATALYST  TO 

CHART  NEW  COURSES  FOR  AMERICAN  INDUSTRY 


Boron  Fluoride  Etherate  .  .  .  valuable  cata- 
lytic chemical  of  wide  ranging  potentiali- 
ties for  American  Industry! 

This  new  liquid  fluorine  compound  has 
a  multitude  of  uses.  Technical  literature— 
filling  volumes — contains  extensive  data  on 
the  reactions  catalyzed  by  BF3  as  well  as 
by  its  complexes  with  other  organic  mole- 
cules. Repeated  reference  is  made  to  its 
superiority  to  other  catalysts  since  reac- 
tions are  moderated  and  fewer  undesirable 
by-products  result. 

Outlined  at  right  are  some  of  the  prin- 


cipal applications  for  HI-'  as  a  catalyst.  Per- 
haps they  indicate  ways  in  which  you  can 
utilize  a  chemical  of  these  characteristics  in 
your  development  or  production  program. 
Boron  Fluoride  Etherate  is  commercially 
available  in  drums.  For  full  information, 
contact  General  Chemical  Company,  Flu- 
orine Division,  40  Rector  Street,  New  York 
6,  N.  Y.  When  writing,  if  you  outline  your 
proposed  application  for  this  new  catalyst, 
the  technical  experts  of  our  Fluorine  Divi- 
sion can  work  with  you  toward  an  early 
solution  of  your  problem. 


GENERAL    CHEMICAL    COMPANY 

40  RECTOR  STREET,  NEW  YORK  6,  N.  Y. 

Half*  and  Technical  Service  Office*:  Atlanta  -  Baltimore  •  Birmingham  (Ala. ) 
Boston  .  Bridgeport  (Conn.)  •  Buffalo  .  Charlotte  (N.  C.)  •  Chicago 
Cleveland  •  Denver  •  Detroit  •  Houston  .  Kansas  City  .  Los  Angeles 
Minneapolis  •  New  York  •  Philadelphia  -  Pittsburgh  •  Providence  in.  I.) 
Han  Francisco  •  Seattle  •  St.  Louis  •  Vtlca  (N.  Y.)  •  Wenatchee 

Yakima  (Wash.) 

In  Wisconsin:  General  Chemical  Wisconsin  Corporation,  Milwaukee,  Wis. 

In  Canada:  The  Nichols  Chemical  Company.  Limited 

Montreal    >  Toronto   •   Vancouver 


ies 


>O.BF3 


Mol.  Wt. 
Melting  Pt. 
Boiling  Pt. 
Spec.  Or. 
%BF,, 


141.9 

Less  than  — 60°C 

125-C 

1.14al25°C 

47.8%  min. 


BASIC     CHEMICALS 


Some  of  the  Principal  Reactions 
Catalyzed  by  BF3 

It  Polymerization  of  unsaturated 
compounds  such  as  olefins,  diolefins, 
vinyl  ethers,  fatty  oils,  and  terpenes. 
The  products  may  be  solid  polymers 
useful  as  plastics  or  liquids  as  in  the 
bodying  of  drying  oils  for  paints  and 
varnishes. 

2.  Condensation  of  aromatic  nuclei 
with  olefins  and  diolenns,  paraffins, 
and  olefins,  and  aromatic  nuclei  or 
olefins  with  acids. 

3.  As  a  cyclizing  agent  for  rubber. 
T.  As  an  esterification  catalyst. 

5.  As  a  catalyst  in  the  synthesis  of 
aliphatic  acids  from  alcohols  and 
carbon  monoxide. 

O.  As  a  promoter  and  dehydrating 
agent  in  the  sulfonation  and  nitra- 
tion of  aromatic  compounds. 


DECEMBER  1946 


PLASTICS 


41 


s 


IZE  IS  Basic— 


S3 

^ 


\ 


But   if   protection, 

color   and   visibility 
are   factors, 

there  is   nocontainer 

quite  so  satisfactory;   so   rugged, 
-^attractive   and    economical   as 


4. 


/ 


PACKAGE  DESIGN  EXPERTS 
ARE   AT    YOUR    SERVICE 


SHATTERPROOF 

SEAMLESS 

FEATHERLITE 

imprinted  during 
manufacturing  process 


-J 


XTEUSION  &  INJECTION 


tiled, 


nines  are 


G/imfjle  .  .  . 


We  have  a  good  deal  more  to  offer  than  our  high 
grade  machines  which  produce  top-quality  Thermo- 
plastics. To  these  we've  added  many  important  little 
improvements.  Those  who  have  us  do  their  moldings 
like  our  ability  to  solve  out-of-the-ordinory  plastic 
problems.  Perhaps  you  would,  also! 

FLEXIBLE  OR  RIGID  RODS— TUBING- 
BELTING— STRIP  and  SPECIAL  SHAPES 
by  EXTRUSION 


WEST  COAST  REPR. :  Container  S«rvic«  Co.,  Lot  Ang»l»i  27,  C«l 

CANADIAN  REPR.:  PUifcc  Supply  Co..  MontiMl  2.  Quebec 

MEXICAN  REPR     M«nu«l  Uon  Or!»g«.  218.  KUxico  D.F 

SO  A  CENT  AMERICAN  REPR    C  Civil*  A  Co .  2  W  45th  St..  N  Y  City 


Simple   or  intricate  products   or  parts 
up  to  22  oz.  per  $hof  by  INJECTION. 


CELLUPLASTIC  CoRPonATion 


PLASTIC     CONTAINERS 

A  NO 

PLASTIC     PRODUCTS 


SO      AVENUE     I 


NEWARK     5      N.    J 


ICI-4JO    K 


42 


I)K(  KMHKK   HMfi 


*  c 


£  5 


Vinyl  Printing 


"Rogers"   board    molding   blank    is   placed   over   the   elec- 
trotype   pattern     before    being     inserted     into     the     press 


The   finished   matrix,    which   is   an   exact    female   mold   of 
the   electrotype   pattern,   emerges   from  the   molding   press 


8,  Pl.i 


A\K\V  advantage  claimed  for  vinyl  printing  plates  is 
an  estimated  10%  saving  in  ink  consumption,  re- 
ported at  the  1946  American  Newspaper  Publishers  Asso- 
ciation Mechanical  Conference  in  Pittsburgh.  This  econ- 
omy derives  from  the  fact  that  vinyl  resin  takes  up  less  ink 
and  hence  tin-  paper  cannot  absorb  more  than  is  necessary 
to  do  the  job.  In  color  printing,  where  ink  cost  is  high,  this 
is  a  factor  which  naturally  assumes  a  considerable  amount 
"I  importance. 

Vinyl  plates  combine  lightness  and  durability  with  a 
-tandard  of  reproduction  more  accurate  and  more  economi- 
cal in  certain  respects  than  electrotypes  and  stereotype-.  In 
national  advertising,  for  example,  where  multiple  duplica- 
tion of  plates  and  low  shipping  weight  are  important,  vinyl 
plates  arc  rapidly  pushing  to  the  fore. 

The  printing  form  is  used  to  make  an  electrotype  pattern 
from  which,  in  turn,  the  female  mold  or  matrix  is  molded. 
In  making  the  plates,  two  plastics  are  used,  thermosetting 
phenolic  for  the  female  mold  and  thermoplastic  vinyl  copo- 
lymcr  for  the  plate  itself.  The  original  pattern  must  !«• 
carefully  examined  for  possible  defects,  such  as  liatter.-d 
type,  shallowness  of  open  area,  or  for  shoulders  on  illti- 


Tile  matrix  blank  is  phenolic  Kni/,-r.s  board  with  a  sprayed 
surface  of  phenol  formaldehyde.  This  is  placed  over  the 
I'.itt.-rii  in  tin-  lM-d  of  a  hydraulic  press  e<|tiip|ied  with  stoj.s 
whose  thickness  control  the  final  depth  of  the  mold.  The 
•red  with  a  thin  metal  protection  plate.  If 
the  pattern  is  uniiMially  deep  some  oin-iators  u-r  a  phenolic 
molding  powder  -iinilar  in  coni|Hisition  to  that  of  the  face 
of  the  matrix  blank.  The  powder  is  sprinkled  over  the  pat- 
tern and  levelled  (lush  with  the  printing  surface.  Since  the 
pattern  is  preheated,  it  is  necessary,  when  the  (M.wiler  is 


used  to  hustle  the  assembly  into  the  press  to  avoid  pre-cur- 
ing.  The  press,  top  and  bottom  platens  heated  to  300°  F, 
is  closed  at  low  pressure  for  Yi  to  3  min  to  permit  the 
phenolic  resin  to  soften.  Time  and  temperature  nu 
cording  to  the  particular  job.  At  the  correct  point,  the  prc" 
is  opened  l/i"  to  permit  any  vapors  to  escape  and  then  the 
pressure  is  quickly  increased  to  600  psi  or  more.  Pressures 
up  to  1700  psi  are  not  unusual.  In  from  8  to  10  min.  the 
resin  cures,  and  when  the  press  is  opened  the  hardened 
matrix  can  IK-  stripped  from  the  pattern  and  used  to  make 
the  actual  vinyl  printing  plate. 

The  matrix  is  placed  in  the  bed  of  the  press  and  cm 
with  granular  vinyl  molding  powder,  with  a  vinyl  sheet 
sometimes  used  as  a  backing.  Some  operators  recommend 
a  heat-conditioning  of  the  vinyl  materials  at  150°-160°  F 
over  a  90-min  period,  at  least.  A  full  day's  supply  can  In- 
conditioned  at  one  time,  since  a  12  hr  exposure  to  that  tem- 
perature is  not  harmful. 

Hear  Is  Evenly  Penetrated 

A  phenolic  panel  of  the  same  thickness  as  the  matrix 
covers  the  assembly,  so  that  heat  will  penetrate  evenly  from 
both  sides.  Tin-  vinyl  (xmder  i-  softened  by  heat,  anil  then 
pressure  is  applied,  which  runs  up  to  1700  psi  for  full-|Kige 
si/es.  The  whole  assembly,  including  the  upper  insulating 
lanel.  is  transferred  to  a  light  press  with  water-on. led 
platens  for  chilling,  after  which  the  finished  plate  is  slrip]K-d 
from  the  mold.  The  process  takes  from  .^  to  4  min. 

I  i.  facilitate  the  stripping  o|x-ration  with  both  matrix 
and  printing  plate,  colloidal  graphite,  brushed  on  and  |M>|- 
isheil.  is  sometimes  used  as  a  lubricant.  \Vhcrc  undercut 
etchings  are  included  in  the  |iattern.  this  is  necessary.  Tin- 
making  of  the  plates  requires  extreme  care,  since  any  dela- 
tions from  the  norm,  especially  with  regard  to  temperature-, 
will  result  in  a  faulty  plate. 

Some  minor  limitations  aie  set  by  vinyl  plates.  <  Irdinary 
steel  routing  tools  must  IK-  replaced  by  ( 'iirrWoy  or  a  similar 
alloy  since  steel  tool-  are  subject  to  rapid  wearing.  Much 
of  this  substitution  can  be  eliminated,  however,  by  careful 


II 


I*  I.. 1ST  1 1'ti 


DKCKMIIKK   I 'UK 


Plates  Reduce  Ink  Costs 


Granulated    vinyl    molding    compound    is    sprinkled    onto 
matrix  and  leveled.  Insulator  is  placed  over  the  powder 


Except   for  trimming,  vinyl   plate   comes   off   matrix   ready 
for  use.    Routing  marks  are  still  visible  in  the  final  plate 


Accurate  and  economical  reproduction,  durability,  and  light 
weight,  are  the  outstanding  qualities  of  vinyl  printing  plates 


preparation  of  the  original  pattern  to  eliminate  the  necessity 
for  the  routing  operation.  Benzol  or  acetone  will  attack 
the  vinyl  plates  and  so  cannot  be  used  as  cleaning  agents, 
but  kerosene,  gasoline  and  naphtha  are  suitable. 

The  Reilly  Electrotype  Company,  the  largest  producer  of 
vinyl  plates  for  national  advertisers  and  one  of  the  oldest 
electrotype  firms,  began  experimenting  with  plastics  plates 
in  1920,  but  the  experiments  were  dropped  because  the  ma- 
terials available  at  that  time  were  not  adequate.  Work 
was  resumed  in  1938  and  plastics  plates  were  put  in  produc- 
tion in  1942.  Output  has  steadily  increased  until  now  vinyl 
plates  represent  a  substantial  proportion  of  the  company's 
ad  plate  business. 

The  scales  are  further  balanced  by  the  reduced  ink  con- 
sumption reported  by  Eugene  Williamson,  of  Williamson 
and  Company,  Caldwell,  N.  J.,  as  noted  above. 

During  the  war  vinyl  printing  plates  were  distributed  by 
the  government  to  the  presses  of'  the  underground  move- 
ments inside  Europe ;  they  were  transported  by  air  and 
dropped  from  planes  at  the  desired  point.  The  overseas  edi- 
tion of  Time  magazine  made  extensive  use  of  the  plates;  it 
being  much  simpler  to  ship  them  and  print  the  magazines  in 
Europe  rather  than  to  ship  the  magazines  themselves.  As 
a  result  the  achievement  of  a  simultaneous  appearance  of 
domestic  and  foreign  editions  was  realized. 

But  wherever  large  scale  duplication  and  light  weight  are 
not  factors,  as,  for  example,  in  the  mass-printing  of  books, 
vinyl  plates  are  not  used.  Since  no  duplication  of  plates  is 
involved  in  book  printing,  set  type  being  used  for  short 
runs  and  electros  for  longer  runs,  the  inherent  advantages 
of  vinyl  plates  cannot  be  utilized  economically. 

A  development  which  indicates  another  eventual  use  of 
(Continued  on  f".ige  65) 


Finished   print   is   an   exact    facsimile   of   the   original    en- 
graving   and    faithful    reproduction    of    the    original    type 


DECEMBER  1946 


45 


An  attractive  assortment  of  various  types  of  decorative 
patterns  which  are  available  with  melamine  laminates 


THE  development  of  new    synthetic  resins  has  always 
been  closely  followed  by  fabricators  and  processors  with 
a  view  towards  utilizing  their  specialized  properties  for  a 
variety  of  applications. 

In  1942  the  Plastics  Division  of  Fabricon  Products,  Inc. 
undertook  to  investigate  the  melamines  as  impregnates  for 
paper  and  fabric  in  industrial  and  decorative  laminates. 
Their  laboratory  tests  showed  that  laminates  made  of  mela- 
mine impregnated  paper  and  fabric  were  highly  resistant  to 
solvents,  and  abrasion,  possessed  excellent  electrical  prop- 
erties, especially  arc  and  track  resistance  and  were  unusually 
clear  and  colorless. 

Hew  Series  of  Laminates 

I'tili/ing  several  ty|H-s  of  melamine  resin  the  Fabricon 
company  produced  a  new  scries  of  laminating  materials 
known  as  Phcnopreg  Ml<  which  were  widely  used  during 
the  war  in  electrical  and  graphic  panels. 

In  the  production  of  electrical  panel  stock  a  number  of 
sheets  of  melamine  impregnated  paper  arc  placed  between 
polished  stainless  steel  plates  and  pressed  tx-twcen  the  heated 
platens  of  a  hydraulic  laminating  press.  The  length  of  time 
required  for  the  heating  process  is  dependent  upon  the  thick- 
f  the  laminate  produced.  After  heating,  the  platens  are 
<••» iled  so  that  optimum  qualities  of  gloss  and  hardness  in  the 
laminate  and  minimum  of  warpagc  can  be  realized. 

<  ienerally,  graphic  laminates  arc  produced  by  laminating 
a  printed  sheet  of  paper  between  a  translucent  surface  sheet 
and  an  opaque  background  of  cither  white  or  colored  paper. 
The  translucent  surface  sheet  pnxluces  an  abrasion  resistant 
surface  so  that  the  final  laminate  is  a  durable  product  ideally 
employed  in  signs,  markers,  instruction  |>ancls,  wiring  and 
oiling  charts,  advertising  displays,  etc. 

I  hese  panels  are  resistant  to  ml.  water,  solvents  of  many 

types,  and  may  be  easily  wiped  clean  of  grease  or  dirt. 

il  methods  of  producing  graphic  laminates  are  used, 

all  based  on  the  principle  of  having  the  printed  diagram,  or 

tinder  a  high  rrsin  content  paper  layer  which  is  highly 

translucent  or  transparent  and  over  an  opaque  background 


Laminating 

with 

Melamine  Resins 


Good  electrical  properties, 
high  resistance  to  solvents, 
distinguish  melamine  laminates 


W«A~  VUt. 

Manager,   Plastics   Division 
Fabricon   Products.   Inc. 


so  that  the  printing  stands  out  by  contrast.  The  printing  inks 
employed  must  be  color  fast  to  the  pH  of  the  melamine  resin, 
resistant  to  the  heat  of  the  laminating  operation,  bleed-proof 
during  lamination,  and  light-fast  in  the  final  product.  The 
vehicle  or  varnish  base  of  the  printing  ink  must  be  carefully 
selected  to  eliminate  possible  decomposition  of  the  vehicle 
at  the  laminating  temperature,  otherwise  a  blistering  will 
occur  over  the  printed  areas.  The  Ink  Division  of  Fabricon 
Products,  Inc.,  initiated  a  development  program  to  produce 
satisfactory  printing  inks  to  be  used  in  graphic  laminates 
and  now  manufactures  I'hcnoprint  Inks  for  that  purpose. 

The  various  methods  employed  in  producing  graphic 
laminates  are  shown  in  the  accompanying  illustration-..  Fig. 
1  shows  a  technique  most  applicable  to  small  production 
rims  and  tin-  simultaneous  production  of  various  si/es  ,  >f 
panels,  inasmuch  as  the  copy  sheets  are  unimpregnatcd  and 
standard  materials  are  employed  regardless  of  the  nature  of 
the  diagram  or  copy.  By  employing  this  method  the  lami- 
nator  can  purchase  standard  grades  of  laminating  materials 
in  any  quantity  and  can  then  have  the  absorbent  paper 
printed  with  various  designs,  copy  and  colors  by  a  local 
printing  establishment.  In  the  laminating  operation  several 
different  types  of  panels  may  be  fashioned  in  one  o|>eiation 
into  one  large  laminate  which  then  can  be  sawed  into  the 
individual  laminates.  By  employing  the  proper  layout  dur- 
ing assembly  of  the  laminating  materials,  the  trim  waste 
may  be  reduced  to  a  minimum.  After  being  sawed  into  in- 
dividual panels,  the  laminates  may  IK-  further  finished  by 
sanding  the  edges  and  drilling  holes  for  mounting 

Fig.  J  illustrates  a  process  which  requires  the  printing 
to  be  in  reverse  on  the  printed  sheet.  After  printing,  the 
paper  is  impregnated  to  the  proper  resin  content  and  treated 
to  the  proper  volatile  content  for  laminating  at  the  specified 
ptesstirc.  The  printing  anil  impregnating  njx-rations  are 
carried  out  with  paper  in  a  continuous  web  or  roll  form  be- 
<  .nise  it  i-  economical  and  lends  itself  readily  to  large  pro- 
duction runs. 

In  Fig.  3,  the  technique  is  similar  to  that  in  Fig.  J.  except 
that  the  former  employs  printing  in  regular  type  on  the 


46 


r  i.  AST  11  • 


I)l.(  KMHKK    I'Urt 


mm 

•'--''tv.-s;. 


'/• 

'./* 


******* 


Industrial's  staff  of  technical  experts  are  particularly 
qualified  to  discuss  problems  in  the  development' 
and  production  of  your  plastic  product.  Their  experts 
know  intimately  from  long  experience  all  phases  of 
the  compression  molding  process.  They  can  assist 
you  in  design,  fit,  finish,  color  and  type  of  material. 
From  deep  draw  units  to  shallow  flat  surfaces  our 
methods  produce  uniformly  high  volume  within 
extremely  close  tolerances.  Whatever  the  nature  of 
your  design  problem,  Industrial's  staff  can  help  you. 
Write  today. 


MOLDED  PRODUCTS  CO. 

2035  W.  Charleston  Street,  Chicago  47,  Illinois 


INDUSTRIAL 

South  Bend  Representative:  Krueger  Sales  &  Engineering  Co.,  P.  O.  Box  419,  South  Bend,  Ind. 


DECEMBER  1946 


PLASTICS 


47 


A 
B 

C 
D 

E 
F 
G 

H 


3  to  7  mil  high  resin  content  melamine  impregnated 
translucent  overlay 

Thin  unimpregnated  absorbent  paper,  printed  with  copy 
or  design  in  "Phenoprint"  inks 

Heavy  melamine  resin  impregnated  opaque  paper  to 
provide  background  for  printed  copy.  Can  be  white  or 
colored 

Phenolic  resin  impregnated  barrier  sheet 

Phenolic  resin  impregnated  core  stock.  Number  of 
sheets  varied  to  produce  desired  thickness 

Phenolic  resin  impregnated  barrier  sheet 

Heavy  melamine  resin  impregnated  opaque  paper 

3  to  7  mil  high  resin  content  melamine  impregnated 
translucent  overlay 


Fig.  1.    Technique  most  applicable  to  small  production  runs 
and  the  simultaneous  production  of  various  sizes  of  panels 

opaque  paper,  which  is  then  impregnated  with  melamine 
resin.  The  latter  method  has  one  point  of  superiority  in  that 
offset  of  the  printing  ink  is  not  particularly  objectionable, 
whereas  the  first  two  methods  described  require  complete 
elimination  of  offset  by  proper  make-ready  and  the  use  of 
-lip  -beets  or  spray  offset  eliminators. 

A  discussion  of  the  above  mentioned  technical  terms  and 
the  printing  procedure  will  show  the  inordinate  care  and 
skill  which  go  to  make  up  but  one  phase  of  the  laminating 
process. 

In  tin-  process  of  printing,  the  methods  employed  are  such, 
that  the  wet  ink  of  the  printed  sheet  or  web  of  paper  comes 
into  intimate  contact  with  the  back  of  the  next  sheet  printed, 
or  into  contact  with  the  next  round  of  paper  as  the  roll  is 
being  wound  up  after  the  printing  process.  As  a  re-tilt,  tin 
wet  ink  tends  to  smudge  on  to  the  back  of  the  next  printed 
sheet  or  the  next  round  of  paper.  The  smudging  of  ink  is 
known  as  offset.  In  order  to  eliminate  it.  various  devices  arc 
employed:  such  as  placing  between  the  sheets  of  printed 
paper,  a  sheet  of  light  weight,  absorbent  paper  which  will 
absorb  the  excess  ink.  These  slip  sheets,  as  they  are  known. 
are  removed  from  the  stack  of  printed  sheets  of  paper  after 
the  ink  has  dried.  Sometimes,  the  printed  surface  is  sprayed 
by  means  of  an  air  spray  with  a  mist  of  starch  solution 
which  falls  on  the  printed  surface  and  prevent-,  the  next 
sheet  of  paper  from  intimately  contartiiiK  the  wet  ink  of  the 
printed  area.  The  fine  layer  of  starch  particles  is  not  ap- 


parent on  the  printed  surface  and  does  not  detract  from  the 
appearance  of  the  printed  sheet.  This  is  described  as  sfrav 
offset  elimination.  By  properly  adjusting  the  ink  feed  of  the 
printing  press  and  the  amount  of  pressure  of  the  printed 
sheet  against  the  type  face,  it  is  possible  to  reduce  to  a 
minimum  the  amount  of  excess  ink  applied  to  the  printed 
sheet.  In  the  printing  trade,  this  regulation  of  ink  and  tin- 
amount  of  pressure  applied  in  printing  operation-  i-  termed. 
make-ready. 

It  is  particularly  important  that  no  materials  be  added  to 
printing  inks  which  have  been  found  satisfactory,  unle--  n 
is  positively  known  that  such  additive-  will  not  affect  the 
quality  and  properties  of  the  printed  surface.  It  is  a  com- 
mon practise  in  printing  and  pressrooms  for  the  press  op- 
erators to  add  materials  to  inks  to  make  them  run  better.  It 
has  been  found  that  many  of  tlie-e  common  additive-  have  a 
marked  and  detrimental  effect  on  the  printed  -beet  when 
employed  in  laminated  panels. 

Whereas  the  methods  shown  in  Fig.  2  and  3  employ  a 
balanced  construction  favoring  a  minimum  of  warpage, 
the  technique  illustrated  in  Fig.  1  does  not,  because  of  an 
extra  sheet  in  the  top  surface  of  the  assembly.  This  may 
produce  a  slight  warpage  of  the  finished  laminate,  in  some 
cases.  However,  there  are  applications  where  even  pro- 
nounced warpage  is  not  considered  objectionable  and  in 
these  instances  the  melamine  impregnated  sheets  may  be 
eliminated  from  the  bottom  side  of  the  panel.  There  are 
many  applications  where  the  panels  are  adhered  to  a  sub- 
structure by  adhesive  materials  and  in  these  instances  the 
panel  remains  flat,  regardless  of  its  unbalanced  nature. 

The  barrier  sheet  show  n  in  all  illustrations  is  used  to  elim- 
inate bleed  through  the  phenolic  core  material  which  may 
result  if  the  volatile  content  is  excessive  for  the  laminating 


3  to  7  mil  translucent  paper,  high  melamine  content, 
printed  on  underside  with  "Phenoprint"  Inks  In  reverse 
type,  prior  to  impregnation 

Melamine  resin  Impregnated  opaque  paper  to  serve  as 
background  for  copy  or  design 

Phenolic  resin  Impregnated  paper  barrier  sheet 


B 
C 
D 

E 
F 
G 


Phenolic   resin   impregnated   core   stock.     Number 
sheets  varied  to  produce  desired  thickness 

Phenolic  resin  Impregnated  paper  barrier  sheet 
Melamine  resin  Impregnated  opaque  paper 
3  to  7  mil  translucent  paper,  high  resin  content 


of 


Fig.   2.     Illustration  of  a  process  which  requires  the 
printing  to  be  In  reverse  on  the  finished  printed  sheet 


48 


I'LASTK'S 


I)K(  K.MHKK  1946 


pressure  employed.  The  use  of  a  low  volatile  content 
phenolic  resin  impregnated  paper  will  act  as  a  barrier  to 
the  resin  flow  of  the  core  material  and  thus  eliminate  any 
staining  of  the  surface  sheets. 

In  addition  to  the  applications  mentioned  previously, 
graphic  laminates  are  produced  for  instrument  and  gauge 
dials,  game  boards,  permanent  charts  and  conversion  tables, 
production  equipment  numbers,  and  such  specialized  appli- 
cations as  wiring  indices  on  electrical  terminal  blocks  and 
panels.  In  the  latter  application  a  standard  panel  or  block 
can  be  made  a  custom  job  in  small  quantities  by  using  a 
small  strip  of  graphic  laminate  fastened  to  the  standard 
panel  or  block. 

Anything  which  can  be  reproduced  by  a  printing  plate 
may  be  produced  in  the  form  of  a  graphic  laminate  in  vari- 
ous colors  at  no  greater  expense  than  the  cost  of  a  printing 
plate,  the  printing  and  the  paper  and  ink. 

Decorative  Laminates 

An  ideal  application  of  the  melamines  is  in  the  produc- 
tion of  decorative  types  of  laminates.  Their  clarity  and 
abrasion  and  solvent  resistance  have  found  wide  favor  as 
table,  bar  and  counter  tops,  door  and  wall  panels,  shelves, 
place  mats,  etc. 

The  decorative  type  of  laminate  is  produced  by  the  assem- 
bly of  materials,  as  illustrated  in  Fig.  4,  followed  by  the 
application  of  heat  and  pressure  as  previously  described.  In 
the  cigarette-proof  type  of  laminate  a  sheet  of  metal  foil  is 
included  in  the  assembly  as  well  as  sheets  of  specially  treated 
paper  to  serve  as  a  bonding  material  for  the  metal  foil.  The 
metal  foil  being  highly  conductive,  dissipates  the  heat,  and 
in  preventing  localized  concentration  of  heat  in  the  laminate 
reduces  the  possibility  of  blistering.  The  printed  pattern, 
or  design,  is  usually  produced  by  rotogravure  printing  in 
the  form  of  a  continuous  pattern.  By  virtue  of  the  perfection 
achieved  by  this  method  of  printing  it  is  possible  to  repro- 
duce cloth,  crystal,  woodgrains  and  other  designs  which 
very  closely  duplicate  the  original  material.  By  combining 
the  technique  employed  in  decorative  and  graphic  laminates, 
it  is  possible  to  produce  laminates  which  have  a  standard 
background  overprinted  with  a  special  insignia  or  trade- 
mark. This  would,  for  example,  make  it  possible  to  produce 
economically  a  table  top  for  a  hotel,  airline,  railroad  or 
country  club  having  a  conventional  pattern,  or  solid  color, 
for  a  background  in  combination  with  the  organization's 
well  recognized  escutcheon  as  an  integral  part  of  the  general 
layout.  This  method  of  producing  custom  decorative  lam- 
inates is  relatively  lower  in  cost  than  the  more  conventional 
method  of  inlaying  the  various  colors  by  making  cutouts 
in  the  base  color  and  inserting  a  die  cut  of  the  same  size, 
but  of  a  different  color.  Techniques  shown  in  either  Fig.  1 
or  3  of  lay-up  assembly  of  graphic  laminates  can  be  employed 
for  the  production  of  customer  designs  in  decorative  lam- 
inates ;  the  choice  of  method  being  dependent  upon  the  pro- 
duction quantity  involved.  The  custom  decorative  laminates 
are  serving  as  coasters,  food  trays,  radio  cabinets  showing 
the  manufacturer's  trademark,  confectionary  menu  boards 
to  match  the  soda  bar  top  and  display  racks  and  easels. 

Another  type  of  laminate  which  illustrates  a  combination 
of  techniques  is  the  translucent  decorative  or  translucent 
graphic  type  of  melamine  laminate.  In  this  type  of  panel 
a  decorative  print  is  laminated  under  an  overlay  sheet  with 
a  backing  of  melamine  translucent  paper  which  results  in  a 
laminate  of  high  translucency  permitting  the  print  to  stand 
out  to  good  advantage  if  the  panel  is  lighted  in  the  back. 
Translucent  decorative  panels  are  being  considered  for 
lighted  window  displays,  counter  easels  with  fluorescent 
lamps  as  a  source  of  light  and  in  sales  displays,  where  the 
panels  may  be  renewed  at  definite  intervals  by  rotating  sets 
(Continued  on  page  94) 


DECEMBER  1946 


B 
C 
D 
E 

F 
G 


3  to  7  mil  translucent  paper,  high  melamine  resin  content 

Melamine    resin    impregnated    opaque    paper,    printed 
with  "Phenoprint"  inks,  prior  to  impregnation 

Phenolic  resin  impregnated  barrier  sheet,  low  volatile 

Phenolic    resin    impregnated   core   stock.      Number    of 
sheets  varied  to  produce  desired  thickness 

Phenolic  resin  impregnated  barrier  sheet,  low  volatile 

Melamine  resin  impregnated  opaque  paper 

3  to  7  mil  translucent  paper,  high  melamine  resin  content 


Fig.  3.    This  technique  is  superior  to  that  shown  in  Fig. 
1  and  2  in  that  offset  of  printing  ink  is  not  objectionable 


B 
C 

D 


3  to  7  mil  high  resin  content  translucent  overlay  paper 
to  increase  abrasion  resistance.  (Not  necessary  on 
solid  colors) 

Melamine  resin  impregnated  printed  opaque  paper  to 
produce  pattern  or  design 

Phenolic  resin  impregnated  barrier  sheet 

Phenolic  resin  impregnated  paper  for  core  or  backing. 
Number  of  sheets  varied  to  produce  desired  thickness 
in  final  laminate 


Fig.  4.     Decorative  laminate  is  usually  produced  in  unbal- 
anced lay-up  as  illustrated.    This  results  in  slight  warpage 


49 


Heat  Sealing-  Plastics  Films 

Proper  temperature  and  pressure  are  important  considerations 
for  obtaining  successful  electronic  welding  of  thermoplastics 


^jfred     ~J\on  Ic 


cr 


THE  JOININ'tl  nf  thermoplastic  materials  by  high  fre- 
quency heat  occupies  the  position  of  a  true  welding 
operation.  The  applied  heat  causes  the  plastics  to  Mitten  and 
the  surfaces  to  fuse  together.  This  fusion  takes  place  in  a 
temperature  range  which  depends  on  the  properties  of  the 
plastic>  and  is  affected  by  the  pressure  applied.  The  achieve- 
ment of  proper  welds  therefore  depends  on  the  attainment 
of  proper  temperature  at  the  interface  of  the  material  being 
joined,  with  a  simultaneous  application  of  proper  pressure. 

Fortunately,  the  amount  of  pressure  required  is  not  criti- 
cal. /  'inylite,  Koroseal  and  Saran  are  welded  with  pressures 
ranging  from  0.5  psi  to  pressures  in  excess  of  100  psi.  An 
increase  in  pressure  has  a  tendency  to  depress  the  range 
of  temperature  in  which  good  welds  can  be  obtained,  and 
aids  in  obtaining  clearly  defined  welds.  However,  high 
pressure  causes  more  pronounced  extrusion  at  the  edge  of 
the  electrodes  and  consequently  is  more  likely  to  cause  thin- 
ning of  the  welded  section.  This  extrusion  and  thinning 
can.  however,  be  controlled  by  careful  adjustment  of  the 
heating  time  and  the  power  applied.  Although  the  latitude 
of  total  pressure  permissible  is  quite  large,  no  such  wide 
tolerance  exists  in  the  distribution  of  pressure.  To  obtain 
uniform  seals  it  is  important  to  have  the  pressure  evenly 
distributed  over  the  entire  section  to.be  sealed.  Fairly  high 
total  pressure  is  recommended  for  thin  films  (.004")  while 
more  moderate  pressures  work  well  for  heavier  materials 
(.012"  and  up). 

In  contrast  to  the  wide  range  of  pressures  that  can  be 
used,  the  temperature  range  in  which  good  welds  can  be 


ftLHS 


>£Lfcraoot 


TIMt>  OfACHIO 


£«•••    "/in1 


Fig  1.  Flow  ol  heat  from  plastic*  to  electrode*  will  occur, 
which  IncreaMi  a*  temperature  ol  plastics  Increase*.  Fiq.  2 
center)  Temperature  Increase*  lor  different  rate*  ol  powei 
input.  Flq.  3  (bottom)  Circuit  delivering  power  to  electrode* 


produced  is  much  more  limited.  Of  course,  the  prcci-e 
temperature  existing  at  the  interface  of  the  materials  being 
joined  cannot  be  readily  measured.  This,  in  itself,  is  not  too 
great  a  disadvantage  as  long  as  it  is  kept  in  mind  that  a 
temperature  range  exists,  and  must  be  reached  in  order  for 
welding  to  take  place. 

The  temperature  of  the  plastics  between  two  electrodes  is 
a  function  of  the  applied  power,  and  of  the  duration  this 
power  has  been  applied.  An  analysis  of  the  heat  flow  in  such 
a  system  is  necessary  for  an  understanding  of  the  rise  of 
temperature  at  the  interface. 

Let  us  assume  that  both  the  plastics  and  the  electrodes 
shown  in  Fig.  1  are  at  the  identical  temperature  before  power 
is  applied.  Now,  once  power  is  applied  it  is  uniformly  gen- 
erated in  all  sections  of  the  plastics  with  an  increase  in 
teni|ierature.  However,  as  the  material  is  in  intimate  contact 
with  the  cold  electrodes  a  flow  of  heat  from  the  plastics  to 
the  electrodes  will  occur.  This  heat  flow  will  increase  as  the 
temperature  of  the  plastics  increases.  The  temperature  will 
consequently  increase  at  a  slower  and  slower  rate  until  a 
limiting  value  is  reached  at  which  point  the  heat-loss  equals 
the  heat  input.  Fig.  2  illustrates  qualitatively  the  manner  in 
which  the  temperature  increases  for  different  rates  of  power 
input. 

Danger  of  Overheating 

The  situation  pictured  in  the  graph  is  typical  where  the 
film  thickness  is  .004"  to  .012".  Let  us  assume  that  a  power 
input  of  n  watts  sq  in.  is  insufficient  to  secure  proper  weld- 
ing teni|K-rature,  no  matter  how  long  the  power  is  applied. 
For  a  power  input  of  2n  watts/sq  in.  the  limiting  tempera- 
ture lies  in  the  welding  range.  A  good  weld  can  IK-  obtained 
but  more  time  is  necessary.  Adjustment  for  this  condition  is 
least  critical  and  no  overheating  is  likely  to  take  place. 
When  the  rate  of  power  input  is  3n,  the  teni|icrature  range 
in  which  welding  will  take  place  is  very  i|iiick!y  reached. 
However,  the  time  will  have  to  be  adjusted  much  more 
carefully,  liecause  of  the  danger  of  overheating. 

In  practice,  the  situation  is  somewhat  less  critical  than 
would  appear  from  these  curves.  This  is  due  to  several 
reasons.  They  are:  gradual  heating  of  the  electrodes,  change 
in  power  factor  of  the  plastics  (usually  rises  with  the  tem- 
perature) and  change  of  power  input  because  of  changes  in 
the  capacity  of  the  electrode  system  (change  of  dielectric 
con-taut  and  extrusion  I. 

For  film  thickne-ses  of  .1(04"  to  .012"  the  power  lost  to 
the  electrodes  is  in  execs-  ,,i  the  power  actually  used  to  raise 
the  teni|X'rature  of  the  plastics.  The  heat  loss  to  the  elec- 
trodes is  approximately  inversely  proportional  to  the  thick- 
ness (1f  film  ti-ed.  The  necessary  minimum  power  input 
consequently  U-comes  larger  lor  thinner  films.  The  follow- 
ing figures  are  minimum  values  of  power  input  at  which 
seals  can  \tc  obtained  for  various  gauges  of  vinyl  film  (for 
joining  two  piece-  I  : 

&«uq.   (in)                                  Minimum  w«ttt   (2  in) 
.012  75—100 

.008  .  110—150 


.004 


.220—300 


It  is  advisable  to  use  rates  of  power  input  of  nearly  twice 
the  limiting  value  for  the  heavier  gauge  films,  in  order  to  oh 


50 


I'l.ASTICS 


I)K(  KMHKK  1946 


TO  ATTAIN  excellence  in 
plastic  molding,  many  steps- 
each  an  essential  part  of  the 
whole  process  — must  be  fol- 
lowed through  accurately  and 
thoroughly. 

Every  step  of  the  way— design- 
ing, mold  making,  molding, 
and  finishing-calls  for  the  high- 
est skill  and  experience,  plus 
the  proper  plant  facilities  for 
efficient  production.  Combined,.  ^ 
these  operations  can  result  ir 
quality  molding... plastics  ikat 
'measure  up"  in  performance, 
appearance  and  cost./ 
MACK  experience  and  proven 
methods,  plus  three  completely 
equipped  plants,  offer  plastic 
molding  that  qualifies.  Your  in- 
quiries are  solicited;  address 
Mack  Molding  Company,  Inc., 
100  Main  Street,  Wayne,  N.  J. 


MOLDED 
EXCELLENCE 


->*: 


ARLINGTON,  VERMONT 
-  MACK  PLANT  AT  MACK  PLANT  AT  ' 

^     'WATERLOO,  P.O.,  CANADA  WAYNE,  NEW  JERSEY    . 

SALES       OFFIC'ES       IN       PRINCIPAL 


DECEMBER  1946 


PLASTtCS 


51 


A  typical  oscillator  circuit  for  plastics  welding  equip- 
ment. Right,  the  lour-post  press  gives  good  alignment 
in  two  directions,  and  is  therefore  used  for  sealing 
products  where  large  rectangular  shapes  are  involved 


tain  welds  in  about  a  second.  For  the  lightest  gauges  the 
value  actually  used  need  only  be  slightly  larger  than  the 
limiting  figure.  Variations  in  the  properties  of  various  types 
of  vinyl,  total  pressure  used,  room  temperature,  etc.,  have 
some  effect  on  the  minimum  values  of  power  input. 

One  of  the  advantages  of  electronic  sealing  over  ordinary 
heat  sealing  methods,  is  the  fact  that  the  interface  of  the 
plastics  film  or  sheets  that  are  joined,  is  at  the  highest  at- 
tained temperature,  while  the  surfaces  adjoining  the  elec- 
trodes are  kept  relatively  cool.  L'sing  power  inputs  only 
slightly  above  the  minimum  values  produces  a  more  favor- 
;iM<-  temperature  gradient  across  the  plastics  than  that  ob- 
tained by  using  relatively  high  values  of  power  input.  How- 
ever, tests  show  that  the  effect  of  this  more  desirable  tem- 
perature gradient  on  the  quality  of  the  weld  is  not  very 
significant. 

Mechanical  Equipment  and  Electrodes 

The  function  of  mechanical  equipnicnt  used  in  plastics 
welding  is  to  provide  proper  and  even  pressure  to  the 
electrode  system.  It  also  must  be  designed  for  rapid  opera- 
tion as  it  is  inefficient  tc.  spend  more  time  setting  up  than 
is  actually  required  in  the  welding  operation  itself. 

The  use  of  air  cylinders  is  the  most  satisfactory  method 
of  obtaining  quick  operation,  reproducible  results  and  ease 
of  adjustment.  Three  inch  cylinders  supplied  with  coin- 
•  'I  air  at  from  JO-frf)  psi  arc  generally  adequate  for 
plastics  welding  operations.  The  pressure  should  be  ad- 
Me  by  means  of  a  diaphragm  type  valve.  The  use  of 
speed  valves  is  recommended  to  reduce  the  impact  of  tin- 
moving  electrode  and  prevent  possible  damage  to  the  plastics 
him. 

I  lu-  framr  holding  the  cylinder  and  guiding  the  movable 
platen  should  l>r  built  somewhat  heavier  than  the  mndi-i.it.- 
.|s.-.|  uoiil.l  indicate.  This  pjaitice  v\ill  improve 
'ii;niiH-nt  of  the  elect  rode*  and  assure  satisfactory  op- 
eration in  a  production  s,-t  up  Certain  type*  of  jigs  have 


been  used  with  good  results  in  production  welding.  The  fact 
that  the  electrodes  may  heat  to  nearly  200°  F  and  transmit 
heat  to  a  jig  must  be  considered  when  designing  for  especial- 
ly critical  jobs.  Warping,  as  well  as  expansion,  with  re- 
sultant jamming  problems,  must  be  avoided. 

It  is  recommended  that  the  entire  jig  be  operated  at 
ground  potential.  It  can  be  placed  on  top  of  a  suitably  de- 
signed generator,  or  on  a  heavy  metal  shelf,  attached  to  the 
generator.  While  not  really  necessary,  it  is  desirable  to 
copperplate  the  entire  jig. 

One  of  the  electrodes  is  attached  to  a  moving  metal  pla- 
ten and  then  grounded.  The  other  electrode  is  stationary 
and  very  conveniently  insulated.  A  flat,  Yi,"  thick  Mycalex 
plate  is  used  for  mounting  and  insulating  the  stationary 
electrode.  This  stationary  electrode  should  be  readily  re- 
movable, in  order  to  facilitate  changing  electrodes. 

Electrode  Design 

The  design  of  proper  welding  electrodes  is  actually  quite 
simple  if  certain  basic  precautions  are  observed.  It  is  im- 
portant to  realize  that  while  insufficiently  rugged  electrodes 
may  work  well  on  laboratory  samples,  they  will  not  be 
satisfactory  in  production. 

It  is  necessary  for  only  one  of  the  electrodes  (preferably 
the  stationary  electrode)  to  conform  to  the  shape  of  the 
desired  weld.  This  simplifies  the  problem  of  lining  up  the 


r 


r~ 

i tp' 

I  i 

I  I 

!: 


i « 


rri 


I'l.ASTI t  * 


I)K(  KMHKR  1946 


-  \t  \ 

•- 


ft 


IN  PLASTICS 
AND  METALS 


The  range  of  products  and 
parts  where  plastic  and 
niclals  can  be  combined 
to  decided  advantage  is 
growing  rapidly  .  .  .  costs 
are  cut  .  .  .  streamlined  design  becomes  prac- 
tical .  .  .  color  can  be  readily  incorporated. 
For  instance,  this  Auto-Lite  distributor  cap 
assures  the  highly  important  precision  posi- 
tioning of  the  metal  contacts,  provides  a 
high  insulation  factor,  gives  low-cost  con- 
struction .  .  .  and  even  this  utilitarian  item 
shows  the  modern  color  eye  appeal  possible 
through  plastics.  The  nipples  are  plastic, 
loo.  in  a  material  which  resists  both  ozone 
and  oil  in  breakdown  tests  far  surpassing 
any  normal  field  conditions. 

THE  ELECTRIC  AUTO-LITE  COMPANY 

Bay  Manufacturing    Division 

Detroit  1,  Michigan  ^^Bay  City,  Michigaij 


Distributor  cap  of  plastics  and 
metals,  nipples  of  Elastomeric 
plastic,  together  with  distribu- 
tor and  spark  plug  wires,-  all 
precision  manufactured  by 
Auto-Lite. 

• 

See  our  catalog  in  Sweet's 
File  for  Product  Designers. 


Tune  in  the  Auto-lite   Radio  Show  Starring   Dick  Haymes 
Every  Thursday  Night,  9=00   P.M.— E.T.  on   CBS 


AVAILABLE   NOW!  Versatile  stock 
designs  for  "ALL-SURFACE"  decoration 


WOOD 

Decorate  furniture, 
toys,  cribs,  hampers, 
novelties  with  decals. 


GLASS 

Decals  are  ideal  for  coast- 
ers, vases,  lamps,  tumblers. 


METAL 

Use  versatile  decals  on 
trap,  canister  sets,  bins 
and  waM»  baskets. 


ADD   NEW   "EYE-APPEAL" 
TO   YOUR   PRODUCT! 

Don't  let  "difficult  surfaces"  deprive  your  product  of  the  added 
sales-appeal  of  colorful  decorations!  The  Thayer  Company  of 
Gardner,  Mass.,  makers  of  this  smart,  upholstered  high  chair, 
successfully  apply  full  color  Meyercord  Decals  to  LEATHKRETTE! 
Regardless  of  the  surface  of  your  product,  whether  plain  or 
painted  wood,  metal,  glass  or  plastic— there's  a  colorful  Mcyorcord 
Decal  to  step  up  its  "eye-appeal."  And  they're  durable, 
washable,  resistant  to  acids,  alcohol  and  stains.  They're 
economical  and  easy  to  apply  at  production  line  speeds. 
Hundreds  of  stock  designs  are  available— right  now. 
Exclusive  designs  can  be  produced  on  request.  Send  a 
sample  of  your  product— or  a  description  of  its  finish  for 
expert  decorating  recommendations.  Address  Dept.  UI-12. 


PLASTIC 

Sinn-  plastic*  rrifuirt-  special  appli- 
cation. Submit  «ani|il<»  (ur  riximi- 
mrndrd  dccal. 


<tfe  MEYERCORD^ 

5323    WIST    IAKI    STRUT 

^  CHICAGO    44,    IL1INOIS  ^ 


World'i     Largutl     D»caltomania     Manufacturer 


The  open  throat  press  is  intended  chiefly  ior  sealing  in  a  single  line,  although  it 
may  also  be  used  for  sealing  in  two  directions  when  one  of  the  dimensions  is  small 


electrodes,  which  otherwise  can  be  quite  a  troublesome  fac- 
tor. 

Copper  is  the  most  satisfactory  electrode  material,  prin- 
cipally because  it  is  least  pitted  by  arcing  which  occasionally 
occurs.  Brass  is  also  suitable,  while  steel  is  not  recommend- 
ed unless  heavily  copper  plated. 

Uniform  pressure  is  of  extreme  importance  in  producing 
good  quality  welds.  Two  different  methods  may  be  used  to 
assure  uniform  pressure.  The  electrodes  may  be  construct- 
ed as  rigidly  as  possible  and  for  moderately  long  seals  a 
truss  type  structure  can  be  used  to  equalize  pressure.  The 
actual  welding  surfaces  should  be  milled,  or  still  better, 
ground  to  be  absolutely  flat.  The  jig  must  be  properly 
aligned  so  that  the  electrode  surfaces  are  parallel.  Little 
trouble  will  be  experienced  with  welds  of  less  than  10".  For 
very  short  welds  almost  any  straight  piece  of  metal  will 
make  a  suitable  electrode;  for  long  seals  (20"  or  more) 
however,  all  the  precautions  mentioned  must  be  observed. 
For  very  long  seals  it  may  be  advisable  to  use  a  series  of  air 
cylinders  to  assure  even  pressure. 

For  Equal  Pressure 

Another  way  of  achieving  equal  pressure  is  to  use  both 
a  rigid  and  a  flexible  electrode.  The  flexible  electrode  is 
made  of  flexible  metal  foil  and  is  supported  on  an  elastic 
cushion  which  forces  it  against  the  rigid  electrode  with  even 
pressure  along  its  entire  length. 

The  first  method  is  preferable  for  most  production  jobs. 
The  flexible  electrode  method  is  useful  for  making  samples 
in  the  laboratory  at  minimum  cost,  and  in  unusual  produc- 
tion jobs  where  it  may  be  extremely  difficult  to  achieve  uni- 
form pressure  with  rigid  electrodes. 

The  amount  of  extrusion  produced  during  welding  in- 


fluences the  strength  of  the  weld  and  the  appearance  of  the 
work.  Partial  control  of  the  amount  of  extrusion  can  be 
realized  by  careful  adjustment  of  time  and  power  input. 
However,  variations  in  line  voltage  and  heating  of  elec- 
trodes as  well  as  variations  in  the  plastics,  seriously  limit 
the  effectiveness  of  this  control.  The  use  of  stops,  is  the 
best  means  of  controlling  the  amount  of  extrusion.  For  light 
gauge  film,  stops  are  usually  not  required;  for  heavy  gauge 
material  they  are  strongly  recommended. 

A  Good  We/d 

Considerable  difference  of  opinion  exists  as  to  what  con- 
stitutes a  good  weld  for  plastics  films.  Some  favor  welds 
with  minimum  extrusion,  while  others  insist  on  so  much  ex- 
trusion that  the  thickness  of  the  weld  is  greater  than  the 
gauge  of  one  of  the  films  constituting  the  seal.  The  amount 
of  extrusion  or  oversealing  required  depends  on  the  material 
and  the  application  of  the  job.  Experience  shows  that  lap 
welds  are  stronger  when  a  moderate  amount  of  extrusion  is 
permitted  to  take  place.  Butt  welds,  however,  can  be  slightly 
undersealed,  especially  when  they  are  subject  to  tension 
only. 

Difficulties  are  frequently  experienced  in  welding  thin 
gauge  films  (.004").  This  is  understandable  when  one  real- 
izes that  necessary  power  input  increases,  but  that  total 
dielectric  strength  of  the  material  decreases  as  the  gauge  de- 
creases. Electrodes  of  low  heat  capacity,  thermally  insulated 
from  the  metal  of  the  jig  solve  the  problem — at  least  in  the 
laboratory.  Such  electrodes  can  be  made  by  placing  metal 
foil  on  Mycalex  bars.  Electrodes  so  constructed  permit  suc- 
cessful welding  of  films  down  to  .002  gauge.  The  power  re- 
quired is  considerably  below  the  minimum  that  would  have 
(Continued  on  page  91) 


DECEMBER  1946 


PLASTICS 


55 


i»    »*'  the    toller    and    hand 

T-ower. 
Clems.  menu- 

and    '  :i   three   separate 

sections.    Light  v. 

is  to  the  ease  of  handling  mower 


•tie-   case,    molded   by 
American  Molding  Co  .  i>  made  of  'Tenitr 

Hiy    and   transparent    red   cover 
slide*  l.jrward  and  down  on  pivots. 
n«niil  Merchandising  Co    handles  the        '•      .• 


Moni>  f>ak."  a  rigid  transparent  cellulose  acetate 

is  us,-  :,la|  packaging  ol  Chatham  baby  blankets 

where  it  aHords   sanitary  protection   and   enhances 
pastel  tones  ol  the  blankets.     Boxes  are  fabricated  by  No 
lonal  Transparent  Co.:  can  also  be  used  for  storing  blankets 


Smart  looking  military  brushes,  with  bristles  of  nylon 
set  in  methyl  methacrylate  backs,  provide  an  ex- 
ample  of  the  utilization  of  plastics  in  the  field  of 
toilet  articles.  Backs  are  cut  from  1%-inch  sheet 
and  hand  polished  by  Shoreham  Manufacturing  Co. 


Smoothly   fashioned   of   cellulose   acetate,   a    unique 
type   of    revolving    tie    rack   will   hold    sixteen    ties. 
yet  occupies  a  minimum  o)  space.  The  item,  desk 
and   manufactured  by  Thomas  Mfg.  Co..  is  dev  si 
to  eliminate  crowding  and  wrinkling,  by  having  each 
tie  hang  free  from  contact   with  other  ties   on   lack 


Clear  acrylic  has  been  used  to  make  a  graceful  and 
ultra-modern  desk  set  which  is  distinguished  by  its 
classic  simplicity  of  line.  The  pens  are  of  phenolic. 
Almac  Plastics,  Inc.,  designed  the  set.  which  is 
available  in  several  attractive,  harmonious  shades 


Shaped  like  a  modified  hour 
glass,  with  the  upper  cap 
serving  as  a  measuring  cup. 
this  cleverly  designed  closure 
can  be  used  to  measure 
ounces  of  bath  oil.  as  well  as 
to  efficiently  cap  the  bottle 


A  NOVEL  closure,  cleverly  designed  to  serve  also  as  a 
measuring  cup,  is  being  molded  by  Shaw  Insulator 
Company  for  Fountainlicad.  Inc..  manufacturers  of  toilet- 
ries, for  use  on  their  foaming  bath  oil. 

The  closure,  of  rose-pink  urea,  is  shaped  like  a  modified 
hour  glass,  with  the  upper  cavity  serving  ;is  the  measuring 
cup.  Its  color  blends  with  the  dark  green,  light  green  and 
amber  of  the  variously  scented  oils,  and  it-,  shape  smoothly 
harmonizes  with  that  of  the  cylindrical  bottle.  The  bottles 
are  individually  packaged  in  a  cellulose  acetate  display  box. 

Threaded  plug*  accomplish  molding  of  threads  on  neck  of  clo- 
sure.    Split  molds  form  handle  and  outer  surfaces  of  closure 


.effectively  setting  off  the  color  combination  of  closure  and 
oil,  and  the  anigraphic  printing  of  the  label. 

Compression  molding  is  expeditiously  done  in  an  eight- 
cavity  semi-automatic  press,  using  steam  oven  preheated 
preforms.  A  split  mold,  necessitated  by  the  undercut  sec- 
tion of  the  piece,  forms  the  outer  surfaces  of  the  closure 
and  a  handle.  The  handle  is  molded  with  a  small  hole  for 
convenient  tagging  of  the  bottle.  The  two  halves  of  the 
split  mold  are  retracted  by  an  air  cylinder. 

The  molding  of  threads  on  the  neck  of  the  closure,  which 
is  inside  a  projecting  lip,  is  accomplished  by  threaded  plugs. 
There  are  four  of  them  on  each  of  the  two  trays  which  slide 
in  and  out  of  the  mold ;  different  sets  being  used  for  the  vari- 
ous sizes  of  bottles — four,  eight  and  sixteen  fluid  ounces — 
which  vary  in  the  size  of  the  threads.  In  operation,  four 
plug  trays  are  used,  arranged  to  work  in  alternate  pairs,  two 
in  the  press  and  two  out  being  unloaded. 

I  he  plunger  section  holds  the  male  elements  which  form 
the  up|K-r  or  measuring  cup  cavity  of  the  closure.  These 
elements  arc  designed  to  add  another  feature  to  the  finished 
product — a  slight  undercut  provides  a  line  in  the  cup  in- 
dicating one  fluid  ounce,  which  is  half  the  full  capacity. 

Four  cams  on  the  plunger  section  are  beveled  so  that  thev 
grip  the  similarly  In-veiled  edges  of  the  mold  frame  when 
the  plunger  section  closes,  securely  locking  mold  halves. 

The  cost  of  the  cap,  including  a  cork  gasket  covered  with 
aluminum  foil,  is  about  eight  cents.  'I  his  is  high  in  com- 
•n  with  a  standard  closure,  but  the  manufacturer  be- 
lieves that  the  heightened  consumer  appeal  of  the  unique 
closure  combining  utility  with  decoi.iti\eness  justifies  the 
i-\|x-ns«-.  END 

58  I)K(  KMHKR  1946 


v\ 


demands  something  "on  the  ball".  . 

...  and  GERING 

has  plenty  as 
your  "anchor  man" 


"Know-how,"  based  on 
years  of  experience  and  re- 
search, have  given  us  years 
of  outstanding  marks  in  re- 
vitalizing plastic  scrap  and 
rejects  .  .  . 

"Standard  procedure"  is 
not  good  enough.  We  have 
learned  many  things  that 
are  not  in  the  books -on  how 
to  inject  added  value  to 
the  orphan  pounds  of  plas- 
tics that  never  go  to  market. 

Putting  them  in  your  profit 
parade,  by  outright  pur- 
chase or  by  giving  them  the 
rej  uvenating"GeringTouch" 
is  right  down  our  alley! 


Write  us  for  details;  or 

Telephone:  CRanford  6-2 9OO 


\lllaslers  oj  ^Illagic  in    C/ieriiio/uas/i 
DECEMBER  1946  PLASTtCS 


ic  conversion 


59 


1 


Transparent  and  adjustable  food  contain- 
er covers  such  as  those  made  by  Protex 
Products  Co.  are  oj  vinyl  film,  with  elas- 
tic edges  which  fit  closely  over  the  tops 
of  bottles,  jars  and  bowls,  permitting 
a  clear  view  of  the  contents  while  help- 
ing to  maintain  the  freshness  of  the  food 


id, 


A  JVew  Cover  Does 
An  Old  Job 


Vinyl  film  and  nylon  are  used  to  aid  in  preservation  and  sanitary 
protection  of  fresh  foods  to  be  stored  in  refrigerator  or  pantry 


FILMS  of  vinyl,  nylon  ami  polyethylene  arc  making  tin- 
life  of  the  busy  housewife  easier  by  serving  as  protec- 
tion  for  bowls,  toasters,  mixers,  milk  bottles  and  platters, 
as  well  as  wrappings  for  vegetables,  meal  ami  jHuiltry. 

Special  Qualifies  Aid  Protection 

The  special  (jiialitics  of  these  plastics  make  them  par 
ttmlarly  adaptable  for  this  purpose  for  they  are  waterproof, 
dtistproof,  greaseproof  ami  mmahsorU-nt.  Ami  they  can 
••asily  be  cleaned  with  warm  water  and  mild  soapsuds.  They 
also  are  durable,  and  do  not  crack  or  deteriorate  with 
changes  in  temperature;  they  are  odorless,  nun-toxic  and 
have  sufficient  elasticity  so  that  they  can  be  stretched  to  fit 
snugly  over  bowls  and  tiottlc  caps,  thus  providing  airtight. 
hygienic  protection.  Their  transluccncy  is  further  con- 


venience for  the  busy  maid  or  housewife,  for  it  permits  her 
to  see  what  the  wrapping  contain-. 

Protex  Products  Company  features  all-vinyl  covers  with 
elastic  edges  which  are  carefully  stitched  for  maximum 
sanitary  protection  of  bowls,  plates,  liottles  and  jars.  They 
are  made  in  sets  consisting  of  live  and  eight  pieces,  respec- 
tively, in  convenient  sizes  so  that  they  will  tit  snugly  over 
all  types  of  kitchen  containers,  from  milk  Unties  to  14" 
mixing  howls.  A  special  cover  for  an  18"  platter  for 
IHuiltry  or  sandwiches  is  also  available.  This  cover 
!  tn  s.-ive  time  Ix-cause  it  makes  unnecessary  the  trans- 
ferring of  food  to  other  dishes  for  storage  in  refrigerator 
and  pantry. 

Food  storage  bags  arc  ingeniously  designed  to  offer  the 
maximum  amount  of  storage  space  within  the  limits  of  the 


60 


I*  LAST  1 1  \S 


DKCKMIIKK  1946 


size  selected.  Square-shaped  and  smartly  tailored,  they 
have  wide  gussets  and  full  width  zippers  for  easy  accessi- 
bility. 

In  the  refrigerator,  food  carefully  preserved  and  pro- 
tected, but  clearly  visible  through  transparent  covering, 
helps  to  maintain  neatness.  These  food  bags  and  moisture- 
proof  covers  for  bowls,  platters  and  bottles  prevent  the 
foods  from  drying  out,  by  retaining  the  moisture  content. 
Butter,  cheese  and  raw  vegetables,  as  well  as  cooked  food, 
meats,  fish  and  fruit,  can  accordingly  be  kept  fresh  for  pro- 
longed periods  of  time. 

Preserves  Vitamin  Content 

In  addition  to  this  factor,  the  coverings  and  wrappers  are 
said  to  preserve  the  vitamin  content  of  the  foods.  From  the 
viewpoint  of  refrigerator  care,  airtight  coverings  aid  the 
housewife  by  preventing  infiltration  of  odors.  This  means 
less  work  in  keeping  the  refrigerator  clean  and  odorless. 

Besides  bowls,  bottles  and  foodstuffs,  various  kitchen  ap- 
pliances require  covering,  and  in  these  cases,  likewise,  plas- 
tics serve  admirably.  They  are  used  to  protect  mixers, 
toasters  and  coffee  makers  from  dust,  grease  and  grime. 
Protex  covers  are  well-styled  and  tailored,  have  plastics 
tape  bindings,  and  are  easy  to  fold  and  tuck  away  when  not 
in  use. 

Bland  Charnas  Co.  features  vinyl  food  bags  which  are 
heat-sealed,  claiming  that  this  results  in  less  strain  than 
machine  stitching.  Covers  are  available  at  present  only  in 
clear  and  frosted  finishes,  but  it  is  expected  that  various 
colors,  in  quantity,  will  make  their  appearance  in  the  near 
future. 

Retail  prices  for  these  vinyl  coverings  range  from  about 
59<f  for  a  five-piece  set  to  $1  for  an  eight-piece  set.  The 
food  storage  bags  cost  about  $1  for  medium  sizes,  $1.25 
for  large  sizes.  Covers  for  kitchen  appliances  range  from 
approximately  59  f  to  $1. 

Nylon  and  Polyethylene  Covers 

The  same  type  of  covers  and  wrappings  are  made  from 
nylon  fabric,  also.  The  Blossom  Mfg.  Co.  features  an 
eight-piece  nylon  set,  consisting  of  a  12"  by  12"  zipper  bag, 
a  4"  milk  bottle  cover,  two  5"  bowl  covers  and  four  other 
bowl  covers  (7",  9",  11"  and  13").  The  retail  price  of  the 
entire  "food-saver"  set  is  about  $1.98.  Although  they  are 
more  expensive  than  the  vinyl  covers,  demand  for  the  nylons 
is  described  as  "very  strong." 

Seal-Sac  covers,  which  are  made  of  B.  F.  Goodrich 
Koroseal,  have  a  wide  variety  of  uses.  They  are  available  in 
the  zippered  bags  for  meat,  vegetables,  pastries,  bread,  etc., 
in  bowl  cover  sets,  electrical  appliance  covers,  platter  covers, 
and  covers  for  cherished  chinaware — in  four  sizes,  each 
cover  holding  12  plates — from  bread-and-butter  size  to 
service  plates. 

A  newcomer  to  the  cover  and  wrapper  market  is  poly- 
ethylene. One  of  the  features  of  this  material  is  its  ex- 
tremely low  moisture-transmission  and  water-absorption 
rate.  It  has  excellent  impact  strength  and  does  not  tend  to 
crack  at  low  temperatures.  At  — 70°  F,  for  example,  it  is 
still  flexible  and  is  therefore  valuable  as  wrapping  for  re- 
frigerated meat,  or  meat  shipped  to  very  cold  regions. 

Its  price  range  is  between  that  of  the  vinyls  and  the 
nylons.  With  a  widening  market,  it  is  expected  that  mass 
production  will  lower  the  price  to  considerably  below  pres- 
ent levels.  Polyethylene  films  are  extruded  by  Visking 
Corp.  and  Plax  Corp. 

Demand  for  plastics  food-covers  and  wrappers  is  "high 
and  getting  higher,"  according  to  a  New  York  City  depart- 
ment store  executive,  who  stressed  the  importance  of  edu- 
cating the  public  regarding  the  hygienic  value  of  the  prod- 
ucts, adding  that  this  would  increase  demand  tenfold  in  a 
short  time.  END 


Platters  of  leftover  meat  or  other  edibles  will  retain  fla- 
vor and  moisture  longer  when  protected  by  vinyl  cover 


Square-shaped  bags  for  storage  of  fresh  vegetables,  fruit, 
meats,  or  fowl  have  slide  fastener  closure,  expansion  sides 


Easily   identifiable   through   transparent   plastics   cover, 
kitchen  appliances  are  kept  free  from  dust,  grease,  grime 


DECEMBER  1946 


PLASTICS 


61 


A  transparent 
ethyl  cellulose 
coating  provide* 
protective  pack- 
aging, reduces 
packaging  costs 
and  bulkineis 


Packaging  Test  Meets 
Re  quirem  en  ts 


Till-,    preservative   and    protective    capacities    of    ethyl 
cellulose  coatings,  as  well  as  their  commercial  use  as 
packaging  material,  were  given  a  dramatic  test  in  a  20,000- 
mile  round-the-world  flight  sponsored  by   Seal-Peel     I  in 
Detroit. 

The  flight  left  Detroit  on  September  30  for  NYw  York 
M.I  1'nited  Air  Lines  and  was  scheduled  to  be  back  in  I  ><•- 
troit  on  October  13,  after  circling  the  globe.  From  October 
14  to  17,  the  objects  to  be  shipped  were  featured  in  a  pi 

ti.,ii  .-it  Motel  Statler,  Detroit,  concurrently  with  other 
adaptations  of  the  Seal-Peel  protective  coating  formulation- 
These  formulations,  based  on  ethyl  cellulose,  arc  supplied 
in  different  compositions  which  meet  the  various  packaging 
problems. 

On  the  flight,  items  such  as  television  tubes,  precision  in- 
struments, blood  plasma,  and  others  equally  subject  to  break- 
age ami  spoilage  were  shipped,  with  Sfal.-l'eel  as  the  sole 
"packing"  material.  Kn  rout.-,  they  were  subjected  to  numer- 
ous climatic  changes  and  at  least  eight  cargo  transfers.  It  is 
claimed  that  this  method  reduces  packaging  cost  and  ship 
ping  hulk  by  as  much  as  two  thirds. 

The  packaging  o|wration  consists  simply  of  dipping  the 

in  the  molten  pla-tic,  material,  which  then  hardens  to 

form   a   protective   cuating  against    rust,   breakage,   fungus 

growth  and  other  shipping  hazards.    To  unpackage.  thccoat- 

mg  is  >|itifkly  and  easily  peeled  off.  END 


Metal  part  is  dipped  in  molten  "Seal-Peel"  plastics  which 
forms   coating.     Right,   coating   is   removed   by   stripping 


n 


PLASTICS 


I>K(  KMRKR  1946 


SEALS  PLASTICS 


replaces  stitching 


Faster •  Stronger-  Cheaper 


No  stitch-perforations  weaken  these  plastic  products  or  mar  their 
eye  appeal!  Like  hundreds  of  other  fast-selling  plastic  items,  their  seams 
are  electronically  welded  by  THERMATRON. 

No  adhesives  or  solvents!  THERMATKON  seals  plastic  seams  air-tight, 
water-tight  and  stronger  —  stronger  than  the  thermoplastic  material 
itself!  With  changeable  dies  machined  to  the  outlines  of  your  products, 
a  single  THERMATRON  makes  a  one-shot  operation  of  sealing  beach 
toys,  shoes,  mitten-iiners  —  hundreds  of  profitable  specialties.  For  rain- 
coats, shower  curtains,  etc.,  THERMATRON  economically  handles  seams 
up  to  72"  long  on  a  production  basis. 

Yes,  THERMATRON  bonds  dissimilar  materials,  too  — vinyl  to  rayon, 
acetate  to  cardboard,  zippers  to  vinyl  film  . . . 

COMPLETE  "PACKAGED"  UNITS! 

THERMATRON  electronic  sealing  units  are  complete  —  ready  to  connect 
to  regular  power  lines.  Compact  —  average  THERMATRON  takes  up  little 
floor  space. 

THERMATRON  dielectric  heaters,  self-contained  and  ready  to  use,  are 
available  to  molders  for  heating  plastic  pre-forms,  plywood,  rubber, 
and  for  general  purpose  use. 

SEND  YOUR  MATERIALS  FOR  TEST  WITHOUT  CHARGE 

Send  us  samples  of  the  materials  you  use.  We  will  test-seal  them  on 
THERMATRON  and  return  samples  promptly  with  full  report.  No 
obligation. 

GET  OUR  BULLETIN  "ELECTRONIC  HEATING  AND  SEALING  WITH  THE 
THERMATRON"  FOR  FULL  DETAILS 

Photos  and  detailed  specifications  on  THERMATRON  units  for  many 
types  of  sealing  and  pre-heating  use;  details  on  THERMATRON  mainte- 
nance service  and  guarantee. 


•Rag.  Trad*  Mark 


Type  K-3-S   THERMATRON 
HEATMASTER  JR."  electronic  sealer 


Handbag  makers  using  the  THERMATRON 
include  Kessler  Bag  (above).  Classy  Leather 
Goods,  Frtedman-Lobet,  Gaybrond  Bag,  Gold- 
lock  Bags,  New  York  Bag,  and  many  others. 


Suspenders  (below)  are  made  on  the  THERMA- 
TRON with  accessory  equipment  by  Tuck  Elec- 
tronic Corp. 


Stitched  seams  puncture 
material,  impair  product 
strength. 


THERMATRON  team: 
Stronger,  water-tight,  air- 
tight —  and  quick  to  make. 
Seams  as  narrow  at  '/u"- 
%"  ore  easily  obtainable. 


Address  Dept.   T-2/ 

DIVISION 


Thermatrom 
RADIO  RECEPTOR  COMPANY, 

Since  ? 922  in  Radio  and  Electronics 
251  West  19th  Street 

New  York  11,  N.  Y. 
Midwest  Sales  and  Service:  Zephyr  Electronics,  Chicago 


DECEMBER  1946 


PLASTICS 


63 


Designer  Pelzold'i  desk,  a  combination  of  plastics  and  wood,  is  part  of 
a  unqle  unit  incorporating  built-in  cabinets  and  drawers.  "Lucite"  drawer 
pulls  afford  simple  unity  when  mounted  on  the  adjoining  drawer  ends 


A  Designer  Sets  an  Example 

Attractive  blending  of  plastics  and  natural  materials  is 
reflected  in  new  office  which  is  comfortable  and  compact 


THH  NKK1)  of  a  new  office  for  (ieneral  Electric  de- 
signer William  B.  Petzold  and  his  staff  raised  the  in- 
teresting question  of  how  a  plastics  designer  would  express 
his  ideas  utilizing  plastics  for  his  own  use. 

Despite  space  limitations,  Mr.  Petzold  has  taken  advan- 
tage of  the  greater  freedom  allowed  him  in  the  absence  of 
the  usual  designer-client  relationship  to  fashion  for  him*elf 
an  office  which  reflects  a  tasteful  blending  of  pla*tic*  :m<l 
natunil  material*.  'I  In-  office,  which  is  located  at  One 
Plastics  Avenue,  Pittsfield,  Ma**.,  is  inviting,  comfortable 
ami  compact;  an  excellent  setting  for  selling  plastics  to  tin- 
designer's  clients.  The  color  scheme  is  predominately  gray. 
augmented  by  a  redwood  tone  on  a  rough-textured  wall. 
Tin-  n*e  of  trans|>arrnt  plastic*  is  particularly  attractive  in 
high-lighting  contrasts. 

Combining  Plastics  and  Wood 

I  hi-  office's  principal  unit  incorporates  the  designer's  de*k. 
built-in  storage  cabinet*  ami  drawer*:  provides  maximum 
working  surface  and  necessary  *lu-lving  facilities.  This 
unit  extends  in  a  gradually  widening  stiriace  acri.**  tl" 
ol  the  room,  hall  way  along  tin-  side  with  the  de*k  section 
projecting  into  tin-  center  ol  the  room.  It  i*  made  of  walnut 
with  a  li-K  laminated  pla*tic*  toil  and  a  tubular  *tip|Miit  oi 
the  *amc  material.  Individual  drawer  pull*,  fabricated  in 
l.ucile.  arc  mounted  on  adjoining  ends  of  the  drawers  to 
present  an  unbroken  line  from  top  to  Ixittom. 

The  fluorescent  lighting  scheme  is  a  smartly  designed  egg 
crate  pattern  of  walnut  dropped  two  feet  from  the  ceiling 
and  covering  approximately  three-fourth*  of  the  room.  l--ich 
24"  module  i*  covered  by  a  panel  of  a  <i-K  translucent 
laminated  plastics  which  gives  a  si.it.  even  ili*tribtition  of 
light 

Plastic*  in  the  furniture  am:  uc»  are  eMen*i\.-l> 


A   portion  of  the  new  General   Electric   office.     An   effec- 
tive combination   of   plastics   provides   beauty   and   utility 


.,1 


Pl.ASTH'ft 


DKCKMKKK  1946 


Built-in  wall  clock  has  "Lucite"  knobs  to  indicate  hours 

used.  A  sofa  of  foam  rubber  construction  is  covered  with 
black  Vinylite;  the  chairs  are  webbed  with  the  same  ma- 
terial. 

Other  accessories  include  a  built-in  wall  block  with  coni- 
cal Lucite  knobs  to  indicate  the  hour,  a  door-pull  fashioned 
of  the  same  material  from  the  designer's  initials  in  script, 
and  a  similarly  made  wall  plate  for  the  light  switch.  A 
Plexiglas  sheet  provides  the  transparent  portion  of  the  door 
leading  to  the  outer  secretarial  office.  END 


Vinyl  Printing  Plates 

(Continued  from  page  45) 


! 


vinyl  printing  plates  is  a  machine  for  curving  the  plate  for 
use  on  a  rotary  press.  The  principle  of  the  operation  is 
simple;  the  vinyl  plate  is  pre-heated  by  water  bath  or  hot 
plate  to  180°  F.  and  curved  by  a  mandrel  and  saddle  of  the 
proper  dimensions.  The  face  of  the  plate  is  protected  by  a 
cork  or  rubber  cushion. 

Specifically,  this  project  is  being  developed  for  printing 
comic  strips.  The  plastics  material  is  ideal  for  this  appli- 
cation since  all  three  of  its  basic  advantages  will  come  into 
play,  the  reported  saving  in  the  consumption  of  high-priced 
colored  inks  being  particularly  important.  A  disadvantage 
in  its  use,  however,  is  the  elevated  temperatures  generated 
by  high  speed  rotary  presses,  which  has  an  adverse  affect 
on  the  vinyl  plates  over  long  runs. 

Other  plastics  materials  in  addition  to  vinyl  copolymers 
have  been  used  as  printing  plates.  The  Johnson  Mat  and 
Stereotype  Company,  in  San  Francisco,  has  developed  prac- 
tical phenolic  printing  plates.  Plates  of  this  type  were  sup- 
plied to  such  customers  as  Standard  Oil,  of  California  and 
Safeway  Stores.  The  process  of  making  phenolic  plates  is 
similar  to  that  previously  described,  with  the  substitution  of 
phenolic  powder  and  phenolic  sheet  for  vinyl  in  the  final 
step. 

Cellulose  acetate  plates,  developed  by  the  Boutwell-Foster 
Company,  Birmingham,  Alabama,  are  also  in  use.  A  pat- 
ented mixture  of  acetate  and  inorganic  materials,  such  as 
white  lead  and  iron  oxide,  gives  a  plate  reported  to  have  a 
greater  resistance  to  cold  flow  than  others. 

But  thus  far,  the  greatest  measure  of  acceptance  has  been 
found  by  the  vinyl  printing  plates.  Some  of  the  advertise- 
ments distributed  nationally  on  vinyl  plates  are  those  for 
Raleigh  Cigarettes,  Pan  American  World  Airways,  Bank 
of  America,  Fleischmann  Distilling  Corp.,  California  Pack- 
ing Corporation,  Petri  Wine,  Nestle  Products,  etc.  END 


'     ***.-**" 
-  j-    ">^^^ 


^ 

The  plunger  and  cavity  molds  above  will 
produce  one  part  of  the  case  for  a  famous 
electric  shaver  .  .  .  Cook  precision  here 
assures  a  "close-shave  in  the  molding". 

Speaking  of  Cook  precision  .  .  .  it's  not 
at  all  confined,  it  can  be  found  in  Cook 
plastic  mold  design  and  Cook  plastic  mold 
engineering  as  well  as  Cook  plastic  mold 
manufacturing. 

Larry  Cook,  head  of  the  fine  group  of 
veteran  plastic  mold  makers  that  make  up 
New  England's  most  complete  plastic  mold 
shop,  will  gladly  advise  you  regarding 
your  plastic  mold  problems  .  .  .  the  advice 
is  free  but  the  results  can  save  you  dollars 
and  dollars! 


RENCE  H.  COOK,  Inc. 


65  Massasoit  Ave.,  East  Providence  14,  R.  J. 
TELEPHONE   EA.   3881 


DECEMBER  1946 


PLA8TMCS 


Extruding  Acrylic* 

(Continued  from  page  33) 


rial.    It  is  difficult  to  prevent  a  few  vacuum  bubbles  form- 
ing near  the  sprue,  as  shown  in  Fig.  4. 

The  mold  will  stick  to  the  material,  making  unloading 
difficult,  unless  it  is  well  polished  and  lubricated  but  it  is 
possible  to  remove  the  end  of  the  mold  if  it  is  a  plain  cylin- 
drical mold ;  and  by  means  of  the  extruder  pressure  to  push 
the  cooled  piece  partly  out  of  the  mold  in  successive  steps 
so  that  a  piece  much  longer  than  the  die  can  be  molded. 
Eventually,  however,  it  is  necessary  to  empty  the  mold,  clean 
and  relubricate  in  order  to  continue.  The  operation  requires 
expert  supervision. 

THE  PLAX  LUBOFILM  PROCESS  OF  CONTINUOUS  EXTRU- 
SION: A  positive  method  which  has  been  working  satis- 
factorily for  years  is  shown  in  diagram  in  Fig.  5.  The  die 
is  very  long,  and  is  held  at  any  desired  temperature  by  an 
automatically  controlled  heater.  The  material  is  supplied 
by  an  extruder,  a  crosshead  and  a  nozzle  into  the  die.  A 
lubricant  which  is  incompatible  with  the  particular  plastics 
being  extruded  is  forced  into  the  die  around  the  space  be- 
tween the  nozzle  and  the  die  wall  so  that  the  plastics  is  at 
all  times  sliding  on  a  film  of  lubricant.  The  lubricant  is  sup- 
plied at  high  pressure  through  a  system  of  piping  contain- 
ing a  filter  and  a  special  control  valve  which  gives  from  7  to 
20  drops  of  lubricant  per  min.  The  lubricant  permits  the 
material  to  slide  through  the  die  toward  the  outgoing  end 
which  is  provided  with  a  stuffing  box  and  a  relief  vent.  The 
pressure,  therefore,  drops  continuously  from  that  of  the 
extrusion  at  the  nozzle,  which  may  be  1000  psi  or  more,  to 
very  slight  pressure  at  the  stuffing  box.  The  friction  of  the 
latter  also  supplies  back  pressure  which  is  necessary  on  large 
diameters.  Because  the  film  of  lubricant  is  only  a  few 
thousandths  of  an  inch  thick  and  must  balance  the  pressure 
on  the  plastics  at  any  point,  the  plastics  is  formed  to  the 
exact  shape  of  the  die  and  cannot  either  pile  up  in  the  die 
or  neck  down  to  give  undersize  rod. 

The  output  of  the  die  is  limited  by  the  time  required  to 
chill  the  center  of  the  rod  to  a  point  where  vacuum  bubble- 
will  not  form  after  the  plastics  leaves  the  die.  Bubbling 
cannot  occur  in  the  die  because  of  the  high  back  pres-ure 
while  the  plastics  is  within  it.  The  dies  are  relatively  ex- 
pensive and  thus  far  only  simple  shapes  have  been  made. 

COOLED  MANDREL  DIE  FOR  TUBING:  To  make  a  heavy, 
bubble-free  extrusion  it  is  necessary  to  cool  the  plastics 
under  pressure.  This  can  be  done  by  the  system  shown  in 
Fig.  6.  A  series  of  hollow  mandrels  are  so  constructed  that 
each  can  he  screwed  into  the  other.  Tlie-<-  an-  then  passed 
through  a  jacketed  chamber  of  medium  length  completely 
filled  with  plastics  from  an  extruder.  The  mandrels  are 
kept  cool  by  a  stream  of  water  causing  a  frozen  film  of  plas- 
tic- t.>  form  on  the  mandrel.  The  thickness  of  this  frozen 
layer  increases  with  time  until  it  has  reached  the  desired 
thickness.  At  this  |M>itit,  a  die  -crapes  off  the  excels  plastics 
which  remains  in  the  chamber  and  the  frozen  tube  and  man- 


drel issue  from  the  die  opening.  Tlu-  mandrel  is  guided  at 
both  ends;  to  the  left,  (Fig.  6)  by  bushings  in  the  chamber 
and  to  the  right  by  a  sliding  guide  arrangement  so  that  tin- 
mandrel  is  held  reasonably  true  to  center.  The  mandrels 
are  later  stripped.  This  system  works  well  with  any  plas- 
tics which  is  heat  stable.  It  is  somewhat  slow  but  several 
units  can  be  attended  by  one  group  of  men  who  also  strip 
the  mandrels.  Simple  or  complicated  shapes  can  be  extruded. 

The  extrusion  speed  is  adjusted  by  a  valve  on  the  incom- 
ing material  from  the  extruder  and  the  mandrel  is  automat- 
ically carried  along  by  the  plastics.  The  exact  speed  is  not 
critical  since  the  die  is  heated  and  can  shave  off  quite  an 
excess  of  frozen  material. 

THE  PLAX  SLIPPER  DIE:  Another  positive  method  u-e 
ful  for  slab  stock  or  rectangular  shapes  is  shown  in  diagram 
in  Fig.  7.  Plastics  from  an  extruder  is  led  between  recip- 
rocating polished  plates  whose  stroke  is  somewhat  more 
than  half  the  width  of  the  slab  being  made.  Two  stationary 
guides  prevent  the  plastics  from  expanding  sidew. 
The  plates  are  flooded  with  a  lubricant  which  keeps  tin- 
plates  covered  with  a  film  at  all  times.  The  plates  are  forced 
to  move  by  a  motor  which  gives  the  motion  AB,  shown  in 
the  vector  diagram.  This  being  the  case,  any  little  tendency 
for  the  plastics  to  move  along  BC  results  in  a  relative 
movement  AC  against  the  slipper  plates.  Thus,  the  plastic- 
can  move  with  very  little  friction  through  the  die.  The 
resisting  force  of  the  die  is,  in  fact,  so  small  that  a  kick 
pressure  device  on  the  extruded  plastics  is  necessary  to 
insure  complete  filling  of  the  space.  The  slipper  die  is  cap- 
able of  extruding  pieces  held  very  accurately  to  size  but  it  i- 
slow  in  pounds  per  hour  since  it  is  necessary  to  chill  the 
material  all  the  way  through  before  it  passes  into  the  air. 
It  produces  continuous  lengths,  however,  and  requires  a 
minimum  of  supervision. 

Defects 

BUBBLES:  There  are  two  kinds  of  bubbles  encountered; 
namely,  general  bubbling  and  vacuum  bubbling. 

General  bubbling  is  apparent  as  small  fine  bubbles  due  to 
liberation  of  gas  during  the  time  the  plastics  is  soft  through- 
out. They  are  present  in  pieces  made  by  direct  extrusion 
and  develop  slowly  during  cooling.  The  bubbles  are  ^en 
erally  distributed  throughout  the  entire  section.  In  some 
cases  where  the  Plax  Lubofihn  system  was  used  the  forma- 
tion of  bubbles  was  due  to  extruding  through  the  die  into 
the  air  at  sucli  high  speed  that  the  center  of  the  rod  wa- 
st ill  hot.  These  bubbles  are  due  to  the  vacuum  created  when 
the  center  tries  to  shrink  as  it  cools  and  is.  therefore,  thrown 
into  hydrostatic  tension  since  the  outer  layers  are  already 
cool  and  cannot  shrink  correspondingly. 

CONTAMINATION  AND  POOR  FLOW:  Under  certain  condi- 
tions, sonic  of  the  material  may  break  down  and  thereby 
develop  different  flow  characteristics.  This  may  result  in  a 
lumpy  wrinkled  surface  on  the  extruded  piece  A  similar 
effect  results  when  two  plastics  of  the  same  kind  but  of  dif- 
ferent flow  characteristics  are  mixed  in  the  liop|x-r  or  when 
scrap  is  added  to  new  powder. 

PERIODIC    I.ixf-  ASH  <  ii\M.t-.  IN  TIIHKSFSS:    Fig.  8 


Fig.  8.    Chatter  mark*  and  screw  puUatiotu  in  tubing,  produced  when  an  e»truder  l»  delivering  material  Irregularly 
Fig    9,   10.   11.     Surface  lint,  which  cause  lack  of  luiter  on  lurlace*  ol  extruded  equare  rod.  round  rod.  and  tubing 


fifi 


I'l.ASTI  1'S 


m:<  KMHKK   1946 


illustrates  the  effect  produced  when  an  extruder  is  deliver- 
ing material  irregularly,  giving  one  cycle  each  revolution 
of  the  screw.  Sometimes,  this  may  be  caused  by  the  way 
the  thread  of  the  screw  bites  the  molding  powder  at  the 
hopper.  It  may  also  be  caused  by  the  difference  in  pres- 
sure caused  by  the  end  of  the  screw  if  the  die  is  very  close 
to  it.  In  other  cases,  a  weaving  action  of  the  extruder 
barrel  due  to  a  bent  screw  or  faulty  drive  may  be  the  offen- 
der. Fig.  8  is,  of  course,  a  particularly  bad  case.  The  screw 
beat  is  plainly  shown  by  illuminating  the  surface  by  a  beam 
of  light  at  grazing  angle.  A  number  of  vertical  lines  are 
also  clearly  visible,  they  occur  in  the  same  pattern  but  not 
in  the  same  frequency  as  the  screw  beat  and  therefore  could 
not  be  due  to  the  screw.  Actually,  they  were  found  to  be 
due  to  vibration  in  the  take  off  device.  Another  class  of 
surface  defects  is  sometimes  caused  by  heavy  vibration  in 
the  factory  which  shakes  the  piece  as  it  issues  from  the  die. 
The  vibration  set  up  by  a  heavy  passing  truck  or  the  thud 
of  a  heavy  casting  produces  a  certain  type  of  surface  defect. 

DULL  SURFACE  :  Quite  often  an  extruded  piece  of  methyl 
methacrylate  will,  at  a  distance,  appear  bright  and  lustrous 
but  will,  upon  close  examination,  present  a  somewhat  dulled 
surface.  Examination  under  a  microscope  reveals  surfaces 
such  as  shown  in  Fig.  9,  10,  and  11. 

Fig.  9  represents  the  side  of  a  square,  extruded  rod  mag- 
nified 20  dia.  Most  of  the  lines  are  only  a  few  hundred- 
thousandths  of  an  inch  deep.  The  die  was  highly  polished 
but  the  extrusion  temperature  was  very  low. 

Fig.  10  shows  the  side  of  a  round  rod  produced  by  direct 
extrusion.  It  appeared  medium  bright  but  buffing  was  re- 
quired to  give  a  high  luster. 

Fig.  11  is  a  magnified  reflection  from  the  side  of  an  ex- 
truded methacrylate  tube  which  appeared  quite  lustrous. 

On  several  occasions  it  was  noted  that  a  set  of  spicules 
developed  when  polystyrene  was  boiled  in  water.  These  are 
actually  small,  flattened  bubbles,  which  reflect  light  from 
their  surface  and  arrange  themselves  in  the  shear  planes  of 
the  material.  Mention  is  made  of  this  condition  because  it 
indicates  points  of  weakness  in  the  structure  which  are  also 
developed  by  the  action  of  certain  chemicals.  It  is  known 
that  chemicals  such  as  carbon  tetrachloride  and  amyl  acetate 
very  seriously  weaken  the  methacrylates. 

During  the  early  days  of  the  war,  attempts  to  cement  ex- 
truded methacrylate  shapes  to  cast  sheets  in  the  production 
of  bomber  noses  resulted  in  severe  cracking  and  crazing. 
Plax  studied  this  problem  and  found  that  like  polystyrene, 
the  methacrylates  required  annealing.  Placing  a  drop  of 
carbon  tetrachloride  into  a  hole  drilled  in  an  unannealed 
methacrylate  rod  produces  an  almost  instantaneous  cracking 
up  in  the  rod.  The  effect  of  one  drop  of  solvent  is  so  potent 
that  the  rod  actually  shatters.  Proper  annealing  will  prevent 
the  cracking  up  of  the  material  when  solvents  or  semi-sol- 
vents are  applied.  Hence,  pieces  which  are  to  be  machined 
or  cemented  should  be  annealed.  Plax  has  been  able  to 
machine  permanently  reliable  parts  of  intricate  design  from 
methacrylate  just  as  they  have  from  polystyrene. 

Summary 

The  extrusion  of  the  methacrylates  is  a  complicated  pro- 
cedure, embodying  the  co-ordination  of  many  processes. 

There  are  three  divisions,  the  direct  (and  uncertain),  the 
semi-positive  and  the  positive.  Only  the  latter  gives  con- 
sistently accurate  shapes,  but  the  number  of  shapes  is  limited. 

A  finished  product  of  extrusion,  if  it  is  to  be  machined  or 
cemented,  should  also  be  annealed. 

There  is  yet  much  to  be  learned  about  the  process  of  ex- 
truding methacrylate  and  it  is  hoped  that  this  article  may 
induce  others  to  add  to  the  rather  meager  fund  of  informa- 
tion on  the  subject.  END 

NOTE:  This  article  was  prepared  from  a  talk  delivered  at  the  recent 
New  England  Section  Meeting  of  the  Society  of  the  Plastics  Industry. 


SPEED  UP 


YOUR 


ASSEMBLING 


with 

HO1TITE 


SHEET  METAL 


Speed  Nuts  are  Speedier 

when  used  with  HOLTITE 
"Thread-Forming"  Screws 


By  cutting  perfect  mating  threads  in  any  material  as  they  are 
turned  in  drilled  or  molded  holes,  these  hardened  speed  fasten- 
ings eliminate  the  time,  cost  and  hazards  of  tapping  operations. 
Setting  up  tighter  they  resist  the  loosening  effects  of  vibration 
and  insure  strong,  enduring  fastening  of  parts  in  your  assembly. 

Our  Engineering  Staff  will  gladly  study  fastening  problems 
that  confront  you,  and  make  recommendations  for  the  most 
efficient  solution.  Frequently,  a  Special  fastening  designed  for 
the  specific  application,  eliminates  the  part  to  be  fastened  by 
including  it  in  its  design.  Thus,  an  extra  part  is  eliminated  and 
a  stronger  fastening  results. 


DECEMBER  1946 


PLASTICS 


Hand  Marking1 
Plastics  in  Color 


- 


Extra  eye   appeal  is  added  to  an  assortment   of  plastics  products  by  applying  colorful  hand  painted  designs 


AN'ENV  means  of  effectively  applying  a  broad  color 
range  of  marking*  to  plastics  materials  has  been  pro- 
duced by  I-"lcx|uil  1'nxluets,  Inc.,  New  York.  A  series  of 
colored  inks  and  a  molded  phenolic  applicator  now  make  it 
possible  to  hand  color  designs  and  lettering  on  various  tyjies 
of  plastics  sheets  and  film-,  and  on  molded  and  fabricated 
plastics  pnxlucts. 


Floquil  pen  barrels  are  being  removed  from  pressure  molds 


Seven  transparent  and  eight  opaque  colors  have  been 
tested  on  acetate,  nitrate,  vinyl,  acrylic  and  other  plastics 
with  good  results  with  the  exception  of  the  acetates  which 
fail  to  retain  the  transparent  colors  permanently.  The  work 
Kloquil  began  in  1938  to  develop  an  all-purpose  marking 
device  has  now  yielded  inks  which  are  --aid  to  dry  instanta- 
neously, to  IK-  waterproof,  sinudgeproof  and  abrasion  re- 
sistant. In  addition,  the  opaque  colors  are  highly  resistant 
to  fading  when  exposed  to  sunlight. 

Excellent  tise  of  the  |xTinanency  of  the  inks  is  being  made 
in  the  marking  of  cellophane  wrapped  frozen  foods.  Weight 
and  identification  notation  must  l>e  marked  on  the  outside 
of  the  package  since  the  moisture  condensation  often  ob- 
scures the  interior.  In  this  connection  the  pens  were  recom- 
mended by  the  I'.  S.  IViiartment  of  Agriculture  for  UM-  at 
North  Makota  State  College  of  Agriculture  to  demonstrate 
frozen  food  marking  to  students  this  past  summer. 

Coloring   Acrylic  Frames 

For  decorative  ap|x-al  the  l-'isk  Industries,  New  Yoik. 
tiscs  the  color  on  acrylic  frames  for  miniature  fine  art  an. I 
photographic  reproductions  which  can  IK-  worn  as  pendants 
and  clips  or  mounted  as  desk  ornaments.  Opaque  colors 
are  applied  with  a  brush,  while  the  phenolic  applicator  can 
IK-  used  with  the  transparent  colors. 

The  chemical  constituents  producing  the  desirable  prop- 
erties of  the  inks  posed  a  problem  in  the  choice  of  applic.it.. i 
material  and  design.  The  high  volatility  of  the  quick-dry- 
ing  inks  necessitated  an  applicator  with  heat  insulating  prop 
i-tties  and  close  fitting  joints  in  order  to  prevent  leakage 
and  excessive  va|mr  loss. 

Important   requirements,   al-n,   were  chemical    rcsi-- 


I'I..\STH   s 


I)K(  KMHKR  1946 


J"^  How  to  Avoid 

r/2fc£?Nft 


Saying  Money 


by  DAMNY  KAYE 


To  avoid  saving  money,  the  first  thing 
is  to  cut  off  all  your  pockets.  (Or  throw 
away  your  purse  and  keep  your  lipstick 
in  your  snood.)  Thus  you  will  have  to 
carry  your  money  in  your  hand.  Which 
will  insure  that  you — 1.  spend  it,  2.  lose  it, 
3.  get  it  taken  from  you — quicker! 


Also  to  be  avoided  like  crazy  are  piggy 
banks  and  sugar  bowls.  Keep  these  out  of 
your  home!  The  kiddies  in  particular  are 
victimized  by  such  devices,  often  saving 
quite  a  bale  of  moolah.  Be  stern  even  if  the 
little  ones  cry— remember  what  money 
could  do  for  them!  And  be  sure  to  avoid 
budgets.  It  is  best  to  draw  your  pay  and 
walk  down  Main  Street  buying  anything 
you  don't  particularly  hate. 


Above  all,  don't  buy  any  U.  S.  Savings  Bonds 
— or  it's  impossible  not  to  save  money!  These 
gilt-edged  documents  pay  fat  interest — 
4  dollars  for  3  after  only  10  years!  There  is 
even  an  insidiously  easy  scheme  called  the 
Payroll  Savings  Plan  by  which  you  buy  bonds 
automatically.  Before  you  catch  on,  you  have 
closets  full  of  bonds.  You  may  even  find 
yourself  embarrassed  by  a  regular  income! 
Get-gat-gittle! 


V 

#l^r//£fi4$y  WX.. 

^*^     ^x  >m  £0/w?  r//^^//  wy/e^a  ^4WiV65 


Contributed  bv  this  magazine  in  co-operation 
ivith  the  Magazine  Publishers  of  America  as  a  public  service. 


DECEMBER  1946 


PLASTiCS 


69 


and  good  fabricating  properties  tu  insure  precision  toler- 
ances. Many  plastics  and  metals  failed  for  a  variety  of 
reasons.  Aluminum  for  example,  while  suitable  in  many 
other  respects,  corroded  quickly  and  caused  the  colors  to 
change  in  the  pen,  and  many  plastics  dissolved  in  the  vola- 
tile solvents  present  in  the  inks.  But  rather  than  sacrifice 
any  desired  marking  effects  by  eliminating  offending  chem- 
ioals.  the  search  for  a  suitable  applicator  material  was 
continued  until  a  molded  phenolic  was  finally  chosen  as 
meeting  all  requirements. 

Tapered  Design 

Taking  advantage  of  the  excellent  molding  characterises 
of  the  phenol ics,  the  manufacturers  first  used  a  tapered  de- 
sign for  the  pen  barrel,  allowing  it  to  fit  snugly  into  a 
nickel-plated  brass  collar  that  holds  the  marking  nib.  This 
design  permits  a  gravity  feed  eliminating  the  threat  of 
leakage  which  is  possible  if  the  two  parts  were  threaded  and 
joined. 

The  applicator  proper  consists  of  three  parts,  the  barrel, 
a  small  button  which  seals  the  barrel  when  cemented  in  place, 
and  a  cap.  In  the  cap  is  a  felt  pad  to  absorb  any  excess  ink 
remaining  in  the  nib  when  the  applicator  is  not  in  use,  and 
an  air  vent  to  permit  the  escape  of  vapors.  The  metal  collar 
is  designed  to  fit  the  tapered  end  of  the  barrel  snugly  and 
is  clamped  about  the  nib  by  a  pre-set  pressure  which  acts 
as  a  flow  control.  The  barrel  holds  one-eighth  ounce  of 
fluid. 

The  applicator  has  been  found  suitable  by  several  fabri- 
cators as  a  container  for  solvents  used  in  sealing  acetate. 
The  lack  of  such  a  device  during  the  war  was  a  sharp 
handicap  to  the  users  of  this  type  of  cellulosic  film 
in  wrapping. 


A  new  model  applicator  has  already  been  designed  with  an 
untapered  barrel  which  is  sealed  at  one  end  in  the  mold- 
ing process,  thereby  eliminating  the  button  of  its  predecessor. 
A  brass  collar  insert  at  the  open  end  of  the  barrel  KTTCI 
to  seat  a  molded  nib  housing  which  tapers  at  both  ends  to 
receive  the  barrel  and  nib  collar.  The  nib  collar  remains 
unchanged. 

Greater  Convenience  in  Filling 

One  of  the  advantages  in  the  new  model  permits  greater 
convenience  in  filling  the  pen ;  the  entire  nib  housing  is 
removed  and  the  barrel  is  filled  through  the  wider  un- 
tapered opening.  In  addition,  the  nib  housing  is  to  be 
packed  with  felt  so  as  to  eliminate  "sweating"  of  ink  from 
the  nib  by  reducing  to  a  minimum  the  amount  which  reaches 
it  and  which  is  necessary  for  operation.  In  this  manner, 
too,  an  air-lock  will  be  created  between  the  ink  and  nib 
controlling  the  expanding  air  which  is  the  principal  cause 
of  "sweating." 

Shaw  Insulator  Company  molds  the  original  applicator  by 
hand  transfer  molding,  and  uses  vertical  compression  mold- 
ing for  the  newer  model. 

The  marking  pens  are  packaged  in  kits  which  vary  from 
one  containing  a  pen,  a  filler  and  a  nib,  to  one  containing 
six  pens,  six  transparent  colors,  a  bottle  of  solvent,  and  a 
full  set  of  twelve  nibs. 

The  components  of  the  felt  nib  sets  have  been  designed  ] 
especially  for  drawing  of  single  lines  of  varying  width,  or 
parallel  lines  of  varying  width,  with  a  single  stroke.  These 
are  particularly  useful  for  border  designs.  Transparent 
colors  only  are  supplied  in  the  kits,  while  the  opaque  colors, 
which  must  be  applied  by  means  of  a  brush,  are  purchased 
separately.  KNI> 


'•?• 


^•^^^^^^^^^ 
•MIOTACTURIRS  AND  PRODUCTION 
MOTORS  OF  THERMO  PIAST.C 
PARTS  AMD  PRODUCTS 


once  tubing- 

rt,ermo  ptasto  «or  volume  «.en 

FROS«X*-H  «ooH.  H   *«•— «  H  Ux*.  • 
Omoment,  and  *apev     -.„  *-.- 


70 


2941  I 

n..\sTi<  •* 


AVE.  .  DETRO.T  7,  M.CH. 


DKCEMBKR  1946 


WHAT'S 


PLASTICS 


Color  for  Injection  Molding  Powders 

Krieger  Color  &  Chemical  Co. 
Hollywood  38,  Calif. 

Called  Poly  Supra  Concentrate  molding  powder  dyes,  these 
new  products  can  be  used  to  color  either  clear  or  opaque  molding 
powders,  and  will  produce  clear  and  transparent  color  effects  on 
cellulose  acetate,  polystyrene,  methyl  methacrylate,  and  vinyl 
molding  powders,  according  to  announcement.  They  are  said  to 
be  color  fast,  and  available  in  a  number  of  shades,  all  of  which 
are  intermixable  for  further  variety  of  tints (622) 


All-Purpose  Press 

Clarendon  Mfg.  Co. 
Chicago  3,  111. 

A  newly  introduced,  hand-operated  bench-type  8-ton  hydrau- 
lic unit  of  modern  design,  the  S-K-W  press  is  announced  as  an 
ideal  molding  machine  for  all  types  of  experimental  and  short- 
run  production  work  on  thermosetting  plastics  material  and  ther- 
moplastics which  can  be  regulated  to  specialized  needs. 

Various  uses  and  applications  are  listed  for  this  machine,  in- 
cluding industrial,  home  workshop,  and  institutional  (for  test- 
ing and  investigation  work).  It  produces  both  plastics  and  rub- 
ber parts,  operates  under  varying  degrees  of  pressure  and  tem- 
perature for  testing  and  checking  materials,  parts  design,  mold 
design  and  for  production  of  a  number  of  kinds  of  short-run  jobs. 

The  S-K-W  press  is  compact,  sturdy  and  durable,  overall 
dimension  being  9l/2"  by  14"  by  26"  high,  and  having  a  mold- 
ing area  approximately  8  sq  in.  Ram  pressure  is  up  to  8  tons. 
Platens,  which  are  5-'/2"  in  diam,  are  electrically  heated  and 
thermostatically  controlled (623) 


All-Purpose  Grinding  Wheel 

The  DO-ALL  Co. 

Minneapolis  4,  Minn. 

The  new  Do-ALL  All-Purpose  grinding  wheel  will,  it  is  said, 
grind  any  kind  of  material,  including  hard  plastics,  and  various 
metals  from  annealed  steel  to  brass,  and  works  equally  well  for 
heavy  fast  roughing  cuts  and  fine  finishing,  producing  a  precision 
finish  comparable  to  that  of  a  300-grit  wheel. 

The  description  adds  that  the  wheel  can  be  used  on  all  types  of 
grinding  machines — surface  grinders,  centerless,  cylindrical,  tool 
grinders,  pedestal,  with  no  alteration  to  the  machine  being  neces- 
sary and  cutting  rate  being  limited  only  by  the  ability  of  the 
machine  itself.  It  is  also  said  that  because  of  unique  cutting 
crystals  and  method  of  bonding  used  in  the  Do-ALL  wheel, 
heavier  cuts  can  be  taken  without  sacrificing  surface  finish  or 
accuracy ;  and  that  the  bond  used  in  making  the  wheels  is  in- 
soluble and  prevents  them  from  weakening  from  use  of  coolants 
in  wet  grinding.  Open  structure  of  the  wheel  is  such  that  the 
work  remains  cool  even  when  dry  grinding.  The  effective  cut- 
ting edges  of  the  crystals  are  broken  down  at  a  very  slow  rate. 

These  wheels  are  available  in  three  types,  and  sizes  range  from 
1"  to  14"  in  diam  by  ;4"  to  3"  in  thickness (624) 


Portable  Rectifier  Unit 

W.  Green  Electric  Co. 
New  York,  N.  Y. 

Claimed  to  be  the  first  of  its  type  on  the  market,  a  new  portable 
rectifier  unit,  designated  as  Model  No.  725S1C,  has  been  an- 
nounced. 

This  rectifier  is  described  as  being  a  complete  DC  power 
supply  source,  with  a  capacity  of  ISOw,  incorporating  all  of  the 
standard  Green  Electric  features,  plus  exceptionally  light  weight 
and  portability;  recommended  by  its  makers  for  laboratory  and 
industrial  applications,  which  are  added  features  in  its  suitability 
for  laboratory  and  industrial  applications. 

The  cabinet  dimensions  of  the  unit  are  14"  by  14"  by  9",  and  it 
weighs  approximately  45  Ib.  Output  is  adjustable  from  0  to  6  v, 
and  has  a  continuous  capacity  of  25  amp. 

Among  features  listed  for  the  unit  are :  Single-phase  full  wave 


circuit,  using  quadruple  protected  selenium  rectifier  element 
which  is  said  to  have  "practically  unlimited  life;"  unit  is  con- 
vection cooled,  has  no  moving  parts,  operates  without  noise; 
heavy  duty  rubber  cord  and  plug  are  incorporated  to  match  any 
standard  AC  outlet ;  and  other  characteristics (625) 

Electronic  Tinier 

Photoswitch,  Incorporated 

Cambridge  42,  Mass.  .     . 

A  new  automatic  timer  for  intervals  from  1/20  sec  to  4  mm  is 
offered  by  its  makers  as  being  particularly  useful  for  process  con- 
trol and  machine  timing  when  long-life,  repeat-cycle  operation,  or 
precise  accuracy  is  a  prerequisite.  Accuracy  variation  is  said  to 
be  less  than  2%. 

This  new  timer,  Type  30HIJ,  is  described  as  providing  four 
basic  types  of  timing ;  interval,  delayed  action,  automatic  repeat, 
and  programming,  as  well  as  a  number  of  variations  of  these 
fundamental  types.  All  of  these  timing  combinations,  incorporat- 
ed in  the  one  timer,  can  be  utilized  by  changing  the  external 
connections  to  the  terminal  board.  In  addition  to  a  maximum 
time  interval,  selector  switch  provides  for  five  times  intervals. 

Flexibility  of  the  entire  unit ;  careful  design  of  basic  circuit  so 
that  it  is  self-compensating  for  changes  in  line  voltage ;  and  em- 
ployment of  only  one  tube  and  one  relay,  are  listed  among  the 
features  of  this  electronic  timer (626) 


For  Trimming  Flash 

Cread  Machinery  Co. 
Bridgeport,  Conn. 

Simple,  speedy  low-priced  machine  for  trimming  flash  from 
round  plastics  molding  is  lightweight  enough  so  that  it  can  be 
carried  from  press  to  press,  thus  allowing  the  operator  to  finish 
his  moldings  during  curing  time  of  the  press.  'The  molding  to  be 
trimmed  is  held  in  a  simple  two-piece  chuck  made  to  fit  the 
article.  This  is  fastened  to  the  faceplates  which  are  supplied  with 
the  machine.  A  slight  pressure  on  the  foot  pedal  closes  the 
chucks,  clamping  the  article  firmly,  then  engages  the  safety 
clutch  and  the  molding  is  revolved  at  the  desired  speed.  The 
flash  is  easily  removed  from  the  rotating  piece  by  means  of  a 
hand  file  without  excessive  cutting  of  the  flats,  which  is  fre- 
quently done  when  abrasive  belts  are  used (627) 

Interesting  Conveyor 

Island  Equipment  Corp. 
New  York  17,  N.  Y. 

A  new-type  conveyor,  recently  placed  on  the  market,  is  de- 
scribed as  a  quick,  positive,  safe  and  economical  means  of  con- 
veying material  from  machines. 

It  has  three  control  hand  wheels.  One,  for  quickly  adjusting 
height  of  the  2'  long  infeed  section  which  fits  closely  to  the  out- 
let of  the  extruder,  has  an  adjustable  up-and-down  movement  of 


To  simplify  for  our  readers  the  task  of  obtaining 
detailed  information  regarding  the  new  products,  proc- 
esses and  trade  literature  described  herein,  plastics 
offers  the  prepaid  postcard  inserted  here. 

Keeping  up  with  every  latest  development  in  one's 
field  is  a  "must."  Speeded  production,  and  the  com- 
petitive drive  toward  lower  manufacturing  costs  require 
that  all  avenues  leading  to  a  solution  of  these  prob- 
lems be  explored  thoroughly. 

Each  item  in  this  section  is  keyed  with  a  number, 
which  should  be  entered  on  the  postcard,  to  expedite 
identifying  the  exact  product,  process  or  publication 
about  which  information  is  desired. 


DECEMBER  1946 


PLASTICS 


71 


6"  from  center,  which  it  is  said  will  lit  "practically  any  need  or 
condition."  The  other  two  wheels,  located  in  different  positions, 
provide  convenient  operating  positions  for  the  travel  speed  of 
the  belt. 

The  machine,  which  lias  large  easy-rolling  casters  to  permit 
quick  and  easy  moving  of  the  equipment,  can  be  supplied  with 
variable  speed  units  from  300  rpm  maximum  to  0  rpm  minimum. 
It  i-  equipped  with  a  special  belt  to  withstand  the  heat  of  tin- 
pans  from  the  extruder (628) 


Versatile  "Electropunch" 

Black  6  Webster.  Inc. 
Boston.  Mass. 

Tliis  recently  introduced  hleftrofunch  occupies  less  than  a  foot 
of  bench  space,  and  has  a  variety  of  uses,  including  stapling, 
marking,  riveting,  piercing,  blanking,  forming,  and  drawing  on 
plastics,  light  metals,  fabrics,  leathers,  etc. 

It  is  described  as  being  simple  to  operate;  its  push  button  con- 
trol may  be  located  so  that  operation  is  automatic  when  work  is 
ted  into  the  machine.  It  is  easily  transportable,  weighing  only 
40  Ib;  a  variable  transformer  which  allows  a  wide  range  of  im- 
pact pressures  is  also  available  for  use  with  the  lilcctropunch. 

Overall  height  is  20",  with  base  6%"  by  9* ;  depth  of  throat, 
from  center  of  spindle,  is  4"  and  height  of  throat  8" (629) 

Protective  Packaging 

Progressive  Systems.  Inc. 
Chicago  1,  111. 

Known  as  I'lustic  Seal,  an  ethyl  cellulose  compound  for  pro- 
tective packaging  of  tools  and  precision  parts  against  rust,  cor- 
rosion and  physical  damage  is  available  in  solid  brick  form,  and 
requires  melting  before  dipping  operations.  According  to  de- 
scription, proper  coating  of  parts  may  be  obtained  at  a  tempera- 
ture of  375°  F;  melting  of  the  bricks  is  done  in  dipping  tanks 
especially  designed  for  1'lastic  Seal  compounds,  and  the  parts  to 
be  coated  are  merely  immersed  quickly  in  the  molten  plastics, 
thus  being  provided  with  a  tough,  corrosion-proof  coating  ap- 
proximately 1/16*  thick,  which  "sets  up"  in  about  30  sec.  The 
mating  is  transparent,  and  can  be  obtained  in  amber,  clear,  or 
various  colors (630) 


Compact  Shredding  Machine 

Universal  Shredder  Co. 
Saginaw.  Michigan 

Originally  designed  to  reduce  all  types  of  scrap  paper  to  ex- 
celsior for  packing,  a  fast-operating  shredding  machine  is  now 
being  used  to  process  or  reclaim  thermoplastic  materials  and 
paper  for  use  as  a  filler  in  low  pressure  molding (631) 


Small  Variable  Speed  Lathe 

Precise  Products  Co. 
Racine.  Wisconsin 

I  >cveloped  to  increase  accuracy  and  speed  in  grinding,  finishing 
and  polishing  small  products  made  of  plastics  and  other  mate- 
rials, this  high  speed  lathe  can  be  used  on  bench  or  table.  A 
conveniently  located  dial  controls  lathe  speeds,  which  are  variable 
from  0  to  40,000  rpm.  Power  unit  can  be  detached  and  used 
separately  as  a  hand  tool (632) 

New  Hydraulic  Pump 

Aldrich  Pump  Company 

Allnnlown,  Pa. 

Recently  designed,  and  scheduled  for  immediate  production, 
the  .ttiirich-l.\tle  Hydropricumatic  Power  Unit  is  operated  by 
a  vertical  double-acting  air  cylinder  and  piston  that  is  direct- 
co«mccted  to  the  upward-acting  pump  plunger  and  yoke-con- 
nected to  the  downward-acting  plunger.  On  hydraulic  demand, 
pump  start*  to  operate  and  continues  until  total  pressures  in 
air  and  hydraulic  sides  equalize. 

Power  is  derived  from  plant  air  pressure  or  from  a  small 
commercial  air  compressor  Various  pressures  can  be  obtained 
by  simple  adjustment  of  self-contained  air  pressure  reducing 
valve,  and  maintained  without  need  for  control  devices  or  l>y 
pass  valve  Pressures  up  to  JO.OOO  Ib  can  be  obtained  with  a 
maximum  air  pressure  oi  only  UN)  II. 

Huilt  for  low  volume,  high  pressure  service,  this  unit  is 
claimed  to  fx-  «imple,  economical  and  highly  efficient (633) 

72 


Literature  Review 

Concerning  "Kriston" 

B.  F.  Goodrich  Chemical  Co. 
Cleveland  14.  Ohio 

A  12-page  illustrated  u-chnical  bulletin  has  recently  been  re- 
leased, covering;  properties  and  processing  information  for 
Kriston,  the  company's  thermosctting  allyl  ester  casting  reMii 
which  is  manufactured  in  a  natural,  uncolored  nionomrr  form, 
as  a  pure,  crystalline  solid  at  ordinary  room  temperature,  melt- 
ing at  110°  to  a  clear  sirupy  liquid. 

The  bulletin  is  titled  "Kriston  Tliermusctting  Resin,"  and  lists 
and  describes  qualities,  characteristics,  and  uses  of  the  material 
together  with  concisely-presented  technical  data  concerning 
it.  (634) 


About  Nylon 

E.  I.  du  Pont  de  Nemours  &  Co.,  Inc. 

Wilmington.  Del. 

Availability,  in  limited  quantities,  of  its  first  booklet  on  nylon, 
since  the  war,  has  been  announced  by  the  company's  nylon  divi- 
sion. Explaining  how  nylon  was  invented  and  how  it  is  made, 
the  booklet  gives  suggestions  for  care  of  nylon  fabrics,  and  con- 
tains a  number  of  interesting  features,  including  a  section  deal- 
ing with  the  properties  of  nylon,  its  elasticity,  resiliency,  and 
various  other  |>ertinent  details. 

The  booklet  is  titled,  "About  Dupont  Nylon" (635) 


Descriptions  of  Two  New  Silicone  Fluids 

Dow  Corning  Corp. 
Midland.  Mich. 

A  recently-released  7-page  pamphlet  descrilK-s  the  company's 
DC702  and  DC703,  two  new  silicone  fluids  for  use  in  high 
vacuum  diffusion  pumps.  Chemical  structure  of  these  fluids  is 
explained,  and  details  on  forepressure,  ultimate  vacuum,  pumping 
speeds,  recovery  time,  and  effect  of  metals  are  included  in  the 
pamphlet.  A  table  of  physical  properties,  and  illustrative  graphs 
round  out  the  technical  information (636) 


Information  on  Glues 

I.  F.  Laucks.  Inc. 
Seattle.  Wash. 

This  is  an  informative  booklet  which  explains  the  basis  and 
various  uses  of  a  number  of  types  of  Laucks  glue,  giving  des- 
cription and  data  on  the  composition  of  the  phenol  formalde- 
hyde resin  glues,  urea  formaldehyde  resin  glues,  melamine  resin 
and  casein  glues,  and  soy  bean  glues. 

The  booklet  is  well  prepared,  and  explanations  are  clear  and 
concise.  12  pages  and  rover,  it  is  adequately  illustrated  with 
photographs,  sketches,  and  diagrams (637) 


Milling  Machine  Catalog 

The  Cincinnati  Milling  Machine  Co. 
Cincinnati.  Ohio 

An  attractive,  35-page  catalog,  recently  published,  gives  spe- 
cific information  on  the  company's  new  No.  2  MI  milling 
machines. 

Highlights  of  design  arc  listed,  and  the  catalog  has  been  care- 
fully prepared  to  provide  clear  and  concise  details  on  character- 
istics and  specifications  of  this  new  line  of  machines.  It  is 
illustrated  throughout  with  photographs,  and  dimensional  draw- 
ings and  sketches  are  provided  to  complete  description  in  fullest 
poxsiMc  detail (638) 

Switch  for  Manual  Safety  Control 

Micro  Switch 
Freepoit,  111. 

\ew  Data  Sheet  No.  38.  comprised  of  4  pages,  provides  data 
on  the  company's  KXK-2RQ4  switch,  devised  for  use  on  manu- 
ally-fed presses  to  reduce  operator  fatigue  and  to  provide  pro- 
tr.-ti.m  for  thr  operator. 

.\d\anlai:es  of  tlir  switch  are  explained,  characteristics  are 
listed,  Miid  diagrammatic  drawings  are  used  to  show  method  of 
attachment  and  operation  .  (639) 


DECEMBER   li 


SPI  Show  Committee  Meets 

The  committee  in  charge  of  the  2nd  National  Plastics  Exposi- 
tion of  the  Society  of  the  Plastics  Industry  held  its  first  meeting 
in  Chicago  on  October  24  to  plan  for  the  event,  which  is  sched- 
uled for  May,  1947,  at  the  Coliseum  in  Chicago.  A  change  in 
the  dates  for  the  exposition  was  decided  upon  at  the  meeting; 
originally  announced  as  May  S  to  11,  these  have  been  changed  to 
May  6  to  10. 

It  was  also  concluded  by  the  committee  that  because  of  the 
large  concentration  of  industry  in  the  Midwest  area,  the  SPI 
exposition  would  be  held  primarily  as  an  industrial  event. 

The  committee,  members  of  which  had  been  named  by  Neil  O. 
Broderson,  president  of  SPI,  consists  of  the  following:  Allan 
Fritzsche,  General  Industries  Co.,  chairman;  R.  E.  Blanchard, 
Stimsonite  AGA  Plastics  ;  Allan  Brown,  Bakelite  Corp. ;  Charles 
F.  Elmes,  Elmes  Engineering  Works ;  J.  R.  Hoover,  B.  F.  Good- 
rich Chemical  Co.;  J.  L.  Howie,  Jr.,  Grigoleit  Co.;  Elmer  E. 
Mills,  Elmer  E.  Mills  Corp.;  E.  J.  Pechin,  E.  I.  duPont 
deNemours  &  Co.,  Inc. ;  J.  W.  Stokes,  Chicago  Molded  Products 
Co.;  Paul  C.  Tietz,  The  Richardson  Co.;  J.  R.  Turnbull, 
Monsanto  Chemical  Co. 


Detroit  Rubber  6  Plastics  Group 

The  fall  dinner-meeting  of  the  Detroit  Rubber  &  Plastics 
Group,  Inc.,  was  held  at  the  Detroit-Leland  Hotel,  on  October 
18.  Featured  speaker  of  the  evening  was  Dr.  Arthur  V.  Tabol- 
sky,  professor  of  chemistry,  Princeton  University,  who  spoke 
on  the  subject  of  "Physical  Properties  and  Molecular  Structure 
of  Natural  and  Synthetic  Rubbers;"  the  talk  was  accompanied 
by  illustrative  slides. 


SPI  Midwest  Chapter  Elects  Officers 

The  autumn  meeting  of  the  Midwest  chapter,  Society  of  the 
Plastics  Industry,  was  held  at  French  Lick,  Ind.,  November  7 
and  8.  The  following  officers  were  elected:  Ralph  Blanchard, 
Stimsonite  Plastics,  secretary-treasurer;  Norman  Anderson, 
General  Molded  Products,  Inc.,  re-elected  chairman;  and  Wil- 
liam K.  Woodruff,  Celanese  Plastics  Corp.,  re-elected  vice- 
chairman. 

At  the  morning  technical  sessions,  the  speakers  and  topics  of 
address  were,  as  scheduled,  E.  B.  Yelton,  speaking  on  "Teflon ;" 
C.  A.  Lydecker,  "Roll  Leaf  Stamping  on  Plastics ;"  Chester  M. 
Kobbins,  "Printing  on  Vinyl  Film;"  and  Frank  Carman,  "Plas- 
tics Materials  Outlook." 

Featured  speakers  at  the  banquet,  which  took  place  on  the  eve- 
ning of  November  7,  were  Dr.  M.  H.  Bigelow,  director  of 
technical  service,  Plaskon  Div.,  Libbey-Owens-Ford  Glass  Co., 
who  talked  on  "German  Plastics" ;  and  Capt.  the  Rev.  Norman 
Rawson,  Hamilton,  Ontario.  Canada,  whose  address  was  titled 
"Beyond  Security." 


Materials  Handling  Exposition 

The  first  national  Materials  Handling  Exposition  has  been 
announced  for  January  14  to  17,  1947,  at  Public  Auditorium, 
Cleveland,  under  management  of  Clapp  &  Poliak,  Inc.,  New 
York. 

Various  systems  and  machinery  for  materials  handling  will  be 
shown  and  all  phases  of  materials  handling  will  be  discussed  dur- 
ing the  four-day  meeting,  according  to  announcement,  with 
special  consideration  for  problems  of  plastic  and  composition. 

The  policy  committee  of  the  exposition  is  headed  by  Earl  I. 
Burke,  manager  of  shipping,  Republic  Steel  Co. ;  others  listed  on 
the  committee  are  T.  O.  English,  assistant  chief  purchasing 
agent,  Aluminum  Co.  of  America;  and  Col.  Albert  B.  Drake, 
materials  handling  engineer,  of  Drake,  Stevenson,  Sheehan, 
Barclay,  Inc.,  New  York. 


Yes,  just  that!  The  accuracy  with  which 
the  earphones  of  this  Aviator's  Micro- 
phone Head-set  is  molded  is  what  helps 
to  make  it  possible  for  the  pilot  to  bring 
the  great  ship  home  "on  the  beam". 
Such  accuracy  is  paramount  at  KXJHN 
&  JACOB. 


Inside  view  of  molded  parts, 
showing  various  plane  surfaces 
and  cavities.  Clean, accurate 
molding  such  as  this  reflects  skill 
in  mold  making  and  production. 


KUHN&  JACOB 


MOLDING    &    TOOL    CO. 

1800      SOUTHARD      STREET,      TRENTON,      N.      J. 

TELEPHONE  -  TRENTON  5391 
CONTACT 
THE  K  &  J 
REPRESENTATIVE 
NEAREST  YOU 


S.  C.  ULLMAN,  55  W.  42NO  ST.,  NEW  YdRK.  N.  Y. 
TELEPHONE-PENN  3-0346 


WM    T.  WYLER.  BOX  126.  STRATFORD.  CONN. 
TELEPHONE- STRATFORD  6-4496 


DECEMBER  1946 


PLASTICS 


73 


ENGINEERING 


By   LEWIS   WINNER 

Moricvf   f»t»arch    £ngin»«r 

Development  of  Coatings 

When,  over  a  decade  ago,  it  was  learned  that  plastics  could 
be  used  to  surface  materials  (particularly  metals),  effectively, 
and  thus  substantially  improve  both  the  mechanical  structure 
and  physical  appearance,  industry  after  industry  began  to  adopt 
plastii  ••>  coatiiiK-.  as  a  standard. 

Originally,  thermoplastics  were  used  for  coatings.  Recently, 
however,  the  trend  has  been  to  baking  enamels  consisting  of 
thermosetting  resins  in  view  of  the  improved  surface  hardness 
provided.  Unfortunately,  the  thermosetting  resins  have  intro- 
duced the  problem  of  blistering,  resulting  from  very  rapid  setting 
and  maximum  hardness  after  a  short  baking  cycle,  the  blisters 
containing  bubbles  of  gas  trapped  in  the  hardened  film.  Al- 
though the  thermoplastics  coatings  were  not  as  sturdy,  they  were 
not  much  affected  by  blistering,  because  the  somewhat  lengthy 
baking  period  required  to  harden  the  surface  prevented  the 
escape  of  any  bubbles  of  entrained  gas. 

To  solve  the  problem,  George  R.  Hoover  and  Noble  E.  Hays, 
Middletown,  Ohio,  have  developed  a  pretreatment  method  for 
ferrous  sheet  metal,  in  which  they  pretreat  sheeting  that  has 
been  galvanized  by  passing  the  galvanized  sheets  through  a  solu- 
tion of  phosphoric  acid,  zinc  phosphate  and  an  oxidizing  agent 
such  as  sodium  nitrate.  This  bath  provides  a  coating  of  zinc 
phos|4iate  to  the  surface  of  the  sheet.  After  leaving  the  bath, 
through  a  set  of  rubber  squeeze  rolls,  the  sheets  are  passed  first 
through  a  cold  water  spray,  then  through  a  hot  water  spray  to 
rinse  off  any  soluble  salts  which  may  be  clinging  to  their  surface. 
They  are  then  passed  through  a  set  of  rubber  rolls  into  a  chromic 


acid  spray ;  a  solution  of  about  3  Ib  of  chromic  acid  per  100  gal 
of  water  at  180°  F.  In  the  final  step,  the  sheets  are  run  through 
another  set  of  squeeze  rolls  to  remove  any  excess  chromic  acid 
solution.  A  blast  of  hot  air  is  then  used  to  dry  the  surfaces. 

Bonderized  sheets  can  also  be  treated  to  prevent  blistering,  by 
using  a  heat  treatment.  In  this  method,  the  sheets  are  passed 
singly  or  in  groups  through  an  open-heated  furnace  equipped 
with  a  conveyer.  The  exact  temperature  of  heat  depends  upon 
the  extent  of  the  galvanized  coating.  Usually  from  450°  to 
500°  F  is  satisfactory  for  a  3  to  7-minute  cycle  range. 

Metal  sheets  treated  in  this  manner  can  be  used  with  such 
thermosetting  resins  as  urea  formaldehyde  and  phenol  aldehyde, 
and  the  glycerol  polybasic  acid  resins,  acetylene  derivatives  and 
polyolefin  resins. 

Hoover  and  Hays  state  that  once  the  pretreated  sheets  have 
been  freed  of  their  tendency  to  produce  blistering  they  never 
regain  it,  despite  normal  handling,  shipping  and  storage. 

Solvent  Problems 

In  the  course  of  investigating  plastics-coating  potentialities, 
research  engineers  used  polymerized  vinyl  compounds  as  a  coat- 
ing. They  discovered  that  these  compounds  were  stable  and  not 
readily  affected  by  concentrated  hydrochloric  or  hydrofluoric 
acids,  or  even  by  mixtures  of  potassium  dichromate  and  sulphuric 
acid.  This  was  found  to  be  particularly  true  of  resins  produced 
by  the  copolymerization  of  a  vinyl  halide  with  a  vinyl  ester  of  a 
lower  aliphatic  acid.  Unfortunately  though,  when  these  com- 
pounds were  applied  to  certain  metals  such  as  zinc,  iron  or  tin, 
at  high  temperatures,  rapid  decomposition  of  the  plastics  re- 
sulted. A  study  of  this  problem  revealed  that  solvents  in  the 
resin  prompted  compound  deterioration.  It  was  also  found  that 
because  of  the  solvents,  poor  color  stability  and  disagreeable 
residual  odors  resulted. 

Recently,  Glenn  H.  Morey,  Terre  Haute,  Ind.,  discovered  that 
the  alkyl  esters  of  levulinic  acid  arc  highly  effective  solvents, 
providing  a  coating  which  is  stable,  has  gcfcnl  color,  and  a  mild 
and  agreeable  odor.  Vinyl  resins  with  which  this  solvent  can 
be  used  include  those  having  a  molecular  weight  above  4000, 
which  are  insoluble  in  toluene.  Such  resins  are  produced  by  the 


SPECIALISTS  IN  SILVERING 


We   are   prepared   to  deliver  high  quality  and   uniform  finishes  on 
molded  and  fabricated  plastics. 

Our  increased  production  facilities  now  enable  us  to  handle  a  large 
volume  of  PLASTICS  MIRRORS. 

Our  new  technique  has  greatly  improved  the  color  values  on  plexiglas 
for  decorative  as  well  as  functional  purposes. 

Your  individual  plastic  silvering  problems  will  be  given  our  prompt 
attention. 


NEW  JERSEY  SPRAYED  PRODUCTS  CO.,  INC 

250  MILL  STREET 
BELLEVILLE  9,  NEW  JERSEY 


TELEPHONES:  BELLEVILLE  2- 


\  2232-3 
14062 


I)K(  KMHKR  1946 


copolymerization  of  a  vinyl  halide  (such  as  vinyl  chloride)  with 
a  vinyl  ester  (such  as  vinyl  acetate). 

In  preparing  the  solvent,  approximately  equimolecular  quanti- 
ties of  levulinic  acid  are  reacted  with  alcohol  in  the  presence  of 
a  catalytic  amount  of  a  mineral  acid,  such  as  sulphuric  acid. 
The  resulting  esters  are  then  purified  by  fractional  distillation. 
Any  of  the  alkyl  esters  of  levulinic  acid,  of  suitable  boiling 
points  and  rates  of  evaporation,  may  be  used  as  solvents. 

In  preparing  a  coating  with  this  solvent,  Morey  used  a  vinyl 
resin  copolymer  consisting  of  approximately  85%  vinyl  chloride 
and  15%  vinyl  acetate  (16  grams  per  100  cc)  ;  butyl  phthalate 
(2  grams  per  100  cc)  ;  ethyl  levulinate  (20%)  ;  ethyl  isobutyl 
ketone  (20%)  ;  and  toluene  (60%). 

Mold  Separation 

The  problem  of  mold-separation  from  a  plastics  article  is  one 
with  which  manufacturers  have  often  been  confronted.  This  is 
particularly  true  where  adhesive  qualities  of  volatile  solutions 
used  in  the  plastics  cause  the  product  to  adhere  to  the  mold. 

To  prevent  such  "product-to-mold"  adherence  and  facilitate 
stripping  of  the  product  from  the  mold  without  injury,  Zachary 
T.  Walter,  Los  Angeles,  Calif.,  has  developed  a  method  employ- 
ing lubricants  and  lubricant  coatings. 

Walter  first  applies  a  coating  of  a  lubricant,  such  as  petro- 
latum, to  the  mold.  Over  this  is  applied  a  thin,  flexible,  pre- 
formed insulating  sheet,  such  as  ethyl  cellulose  film,  with  a 
thickness  of  from  .001"  to  .003".  This  coating  does  not  interfere 
with  the  article  which  is  being  formed.  In  fact,  the  lining  may 
be  used  as  an  integral  part  of  the  product,  if  desired.  Such  a 
plastics  article  can  be  formed  by  superposing  successive  lamina- 
tions of  jute,  and  impregnating  with  a  colloidal  volatile  solution 
containing  ethylcellulose  and  the  necessary  solvents,  allowing 
each  successive  lamination  to  set  before  applying  the  next  one. 

Unique  Spinner 

With  the  development  of  attractively  colored,  sturdy  plastics 
has  come  a  trend  to  plastics  ware  of  the  pottery  and  ceramic 
type.  As  a  result  of  this  interest,  special  kinds  of  forming 
equipment  have  been  developed.  Recently,  William  J.  Baird 
and  Wm.  M.  Sparks  of  Birmingham  and  Inkster.  Mich.,  designed 
a  pottery  and  ceramic  ware  machine,  using  a  unique  type  spinner 
for  packing  and  troweling  the  plastics  material  into  the  mold. 

The  spinner's  external  shape  corresponds  to  the  inner  shape 
of  the  object  to  be  formed.  The  spinner  can  be  supported,  ro- 
tated, or  moved  axially  on  a  rotating  spindle.  On  the  lower 
end  of  the  spinner  body  is  a  nose  with  strips  or  bands  of  flat- 
tened surfaces  for  troweling  and  working  the  plastics  material. 

For  trimming  and  removing  the  flash  around  the  upper  edges 
of  the  object  being  molded,  the  upper  end  of  the  spinner  body  is 
provided  with  a  trimmer  flange  which  projects  outward,  as 
the  overhanging  rim  of  lateral  flange  protects  operator's  fingers. 

Treatment  for  Vulcanization 

Many  rubber-like  polymeric  plastics  items  are  non-tacky  and 
thus  are  not  readily  vulcanizable.  Such  plastics,  which  include 
a  2-aryl-l  alkene  and  an  alpha-beta  unsaturated  ketone,  copoly- 
mers  of  an  aliphatic  conjugated  diolefine  can  now  be  made  tacky 
by  means  of  a  process  developed  by  Robert  R.  Dreisbach,  Edgar 
C.  Britton  and  Walter  J.  LeFevre,  Midland,  Mich. 

The  desired,  rubber-like  condition  is  obtained  by  incorporating 
between  8%  and  20%,  by  weight,  of  a  tacky  copolymer  of  a 
diolefine,  a  2-aryl-l-alkene  and  an  unsaturated  ketone  to  the 
non-tacky  copolymer. 

The  tacky  type  of  copolymers  preferred  in  this  process  are 
those  composed  of  from  37%  to  65%,  by  weight,  of  an  aliphatic 
conjugated  diolefine,  20%  to  60%  of  an  unsaturated  ketone  and 
from  1%  to  30%  of  a  2-aryl-l-alkene.  These  compounds  are 
polymerized  while  in  an  aqueous  emulsion  which  is  of  a  pH 
value  below  3,  and  which  contains  an  iron  salt. 

Polymerization  is  carried  out  by  heating  the  emulsion  in  a 
closed  container  to  between  60°  and  100°  C,  until  from  85% 
to  95%,  by  weight,  of  the  polymerizable  compounds  have  been 
reacted.  This  takes  from  15  minutes  to  1  hr  heating  time. 

The  resultant  tacky  mixtures  can  be  compounded  with  vul- 
canization accelerators  and  plasticizing  agents.  Dreisbach,  Brit- 
ton  and  LeFevre  state  that  the  tacky  plastics  material  can  be 
applied  to  rayon,  cotton  or  other  materials,  and  vulcanized. 
After  this  operation  the  tackiness  disappears  and  the  rubber- 
like  material  remains  firmly  bonded  to  the  fabric.  END 


THERE  ARE 

TWO  SIDES 

TO  EVERY  STORY 


YOU  may  be  a  plastic  buyer 
who  is  looking  for  the  best  in 
such  stock  items  as  picture  frames, 
door  plates,  drawer  pulls  01 
cable  clamps 

OR  you  may  be  a  manufacturer 
who  is  looking  for  a  reliable, 
complete  custom-molding  service 

IN  EITHER  CASE,  the  record  of 
Continental  Plastics  Corporation 
insures  the  finest  in  precision 
craftsmanship,  originality  and 
economy. 


Send  or  bring  in  your  sample 
product  or  blue  prints  for  an 
honest  and  accurate  appraisal. 


CONTINENTAL 

PLASTICS  CORPORATION 


308  WEST   ERIE   STREET 


CHICAGO   10,   ILL. 


DECEMBER  1946 


PLASTICS 


75 


INDUSTRY  HIGHLIGHTS 


Volume  production  oi  prefabricated  homes  ••]  ahiiuinuin  and 
plastics  lor  temperate  climates  is  being  seriously  considered  by 
Consolidated  Vultee  Aircraft  C'orp.,  according  to  a  statement 
recently  made  by  Harry  \Yoodhcad.  president  of  the  corporation. 
He  added  that  the  company's  preliminary  studies  indicated  that 
"large-scale  production  of  homes  which  the  average  family  can 
afford  is  practical,  provided  that  problems  of  material  and 
equipment  supply  can  be  overcome." 


A  two-bedroom  home  of  the  type  contemplated  would  be 
equipped  with  a  refrigerator,  range,  hot  water  heater,  complete 
bathroom  and  kitchen  fixtures,  and  space  heating  equipment,  and 
would  fully  meet  all  existing  sanitation  and  fire  protection  stand- 
ards, said  Mr.  Woodhead. 

Any  objection  to  "stereoty|>ed  homes."  lie  explained,  would  be 
overcome  by  the  fact  that  the  exterior  appearance  of  the  struc- 
ture which  the  company  is  designing  can  be  modified  by  arrange- 
ment of  patio  walls  supplied  with  the  house,  and  by  variations 
in  color  schemes. 


The  second  revised  edition  of  "Plastics — The  Story  of  an 
Industry,"  is  now  ready  for  distribution,  according  to  announce- 
ment made  by  Xeil  O.  Broderson,  president  of  the  Society  of 
the  Plastics  Industry.  SPI  advises  that  demand  for  copies  of 
the  booklet  has  been  so  great  that  the  organization  is  making 
tirst  release  of  this  third  printing  to  universities  and  libraries 
which  have  requests  on  file.  Chief  purpose  of  the  booklet  is  ex- 
planation of  pertinent  phases  of  plastics  -the  various  chemicals 
ami  resins  and  their  applications  in  today's  world.  Diagrams 
and  a  2-pagc  color  plate  illustrate  methods  and  products,  and 
.flditioiis  to  the  work  include  data  on  recently  developed  mate- 
rials, as  well  as  on  innovations  in  plastics  production  and  experi- 
mentation. A  revised  listing  of  educational  institutions,  in  the 
I'nitcd  States  and  Canada,  approved  by  the  Society,  and  the 
plastics  courses  offered  the  academic  and  trade  school  student 
by  those  institutions. 


Recent  communication  from  Render  Co.,  Ltd.,  San  Fran- 
cisco, advises  that  the  stock  of  retiring  president  K.  G.  Danielson 
has  been  purchased  by  the  company.  Robert  Coleman  Gray,  who 
was  formerly  vice  president,  accordingly  become-  sole  stock- 
Ixildcr  and  assumes  presidency  of  the  reorganized  company.  The 
firm,  which  was  formed  in  1918  as  a  partnership  l>y  Mr.  Daniel- 
sot)  and  Thomas  15.  Gray,  father  of  the  new  president  of  the 
company,  pioneered  in  the  fields  of  electronics  ami  plastics 

Plan-  for  expansion  ot  Render's  activities  in  plastics,  radio. 
television,  and  allied  fields,  will  be  announced  in  the  near  future. 


Acquisition  ot  the  Smith- Davis  Paint  t  «>.  I  "-  Vugi-lc-.  has 
been  announced  by  Maa-  *  \YaId-trin  Co.  Newark.  N.  J.  Mann 
failure  of  industrial  finishes,  tr.nli  sale-  and  maintenance  sales 
paint*.  i»  to  lie  continued  by  the  new  ly-acquired  plant,  and  field 
aitivitirs  are  !••  IK-  carried  on  by  .  oinliiiiinit  s;iles  lone-  of  both 
organizations 

Two  newly  perfected  Imfting  com|>oun<U  arc  being  pro- 
duced by  Plastics  Masterpiece*.  Lot  Angeles.  Called  Lucy- 
I'ltx  and  Caly-Hak.  these  compounds,  it  is  claimed,  will  perform 
simultaneously  thr  operation-  of  grinding,  polishing,  and  waxing, 
in  most  in-t.m>  •  -  elimitiatitiB  th-  tor  previous  sanding 


Described  as  being  dustk-ss,  non-greasy  and  non-staining,  the 
new  products  are  said  to  be  fast-acting,  "non-burning"  to  the 
plastics,  and  productive  of  high  polish.  Lucy-Plex  is  especially 
recommended  by  its  makers  for  use  on  methyl  methacrylate 
plastics,  while  Caly-Rak  is  designated  as  being  particularly  suited 
for  use  on  phenol  formaldehydes,  and  cast  phenolics. 


In  recently  conducted  fatigue  tests  on  two  pieces  of  1/16"- 
thick  duraluminum,  cemented  together  with  a  new  type  of  plastics 
adhesive,  the  strength  of  the  metal,  under  bending  stress.-.  :- 
said  to  have  been  less  than  that  of  the  adhesive.  Repeated  alter- 
nating loads  up  to  5,000,000  load  cycles  were  applied  to  the  fifteen 
specimens  of  24ST  aluminum  alloy  used  in  the  tests,  and  in  all 
cases  but  one  the  adhesive  held,  while  the  metal  itself  fractured. 
The  tests,  designed  to  simulate  actual  service,  were  conducted  by 
the  Sonntag  Scientific  Corp.,  on  a  Model  SF-01-U  universal  test- 
ing machine  as  part  of  a  series  for  the  American  Society  of  Test- 
ing Materials.  Adhesives  used  were  Redux,  made  by  Resinous 
Products  &  Chemical  Co.,  and  Cycleweld,  a  product  of  Chrysler 
Corp. 

Opening  of  a  new,  suburban  studio  of  design  at  6831  \V. 
34th  St.,  Berwyn,  111.,  has  been  announced  by  Joseph  Palma,  Jr., 
industrial  designer,  who  advises  that  his  work  will  continue  to 
be  the  styling  of  products,  in  which  he  has  specialized  for  ten 
years. 


Construction  of  a  new  plant  building,  90  by  200  it.  is  part  of 
the  expansion  program  of  Kampa  Mfg.  Co.,  Milwaukee.  The 
new  structure,  together  with  a  4000  sq  ft  Quonset  type  warehouse 
lately  purchased  by  the  company,  will  provide  22,000  sq  ft  of 
space,  according  to  Edmund  Kampa,  president  and  founder  of  the 
tirm,  which  was  organized  in  1941. 

The  new  building  is  to  include  a  complete  tool  and  die  shop,  a 
display  room,  and  offices  for  production  personnel,  as  well  as 
equipment  for  the  injection  and  compression  molding  of  plastics 
and  machinery  for  molding  articles  of  rubber. 

The  firm  expects  to  increase  its  production  of  plumbing  sup- 
plies, towel  bars,  and  various  other  household  accessories. 

Exporting  to  South  Africa  and  to  South  America  has  recently 
been  begun  by  the  Kampa  Co.,  and  Mr.  Kampa  looks  forward  to 
increased  activity  for  his  lines,  in  both  of  those  markets. 


A  new  plastics  material  firm,  Thor  Kay  Productions,  has 
begun  operations  at  126-130  E.  59th  St.,  New  York  City,  headed 
by  K.  Thor  Kay,  display  artist  and  designer. 

Present  plans  of  the  company  include  processing  and  fabrica- 
tion of  plastics  for  counter,  window,  and  booth  displays ;  pack- 
aging and  gift  wrapping;  murals,  screens,  frames  and  other 
ornamental  applications.  In  addition,  the  firm  will  offer  con- 
sulting, designing,  technical  and  manufacturing  services,  and 
will  specialize  in  production  of  fluorescent  materials,  for  use  un- 
der ultra-violet  "black  light."  L.  G.  Balderston  is  art  director 
of  the  new  organization,  and  J.  M.  Gordon  laboratories  will 
act  as  technical  advisors 

Opening  of  what  is  said  to  be  the  first  plant  for  the  manu- 
facture of  liquid  urea  resin  adhesives  in  North  Carolina  has  been 
announced  by  the  Casein  Co.  of  American  Division  of  the  r...rdi  n 
Co.  The  new  plant  is  located  at  Kernersville. 

The  recently-formed  Dim- Plastics  Company,  New  York 
City,  will  engage  in  custom  and  proprietary  molding.  The  new 
concern,  which  is  located  at  227  \V.  64  St..  was  organized  by 
Mrs  l)i\ey  ltarr\  ( 'arr  in  partner-hip  with  Herman  Strully. 
and  is  at  present  producing  buttons  and  poker  chips. 


Rohm  ft  Hut  Co..  Philadelphia,  het  announced  that  due  lo 
increased  production,  it  hat  been  potiibl*  to  reduce  pricei  of 
th*  company'i  Pltitnr-M  ( modified  ttyrene  copolymer  mold- 
ing powder),  in  both  natural  and  colon,  effective  November 
I,  1946. 


76 


DECEMBER  1946 


Richard  E.  Booth  has  been  made  head  of  product  research 
section  of  Van  Doren,  Nowland  &  Schladermundt,  industrial 
designers,  New  York  and  Philadelphia. 

*  *     * 

A.  L.  Werner,  formerly  of  Pittsburgh  Plate  Glass  Co.,  indus- 
trial finishes  division,  has  joined  the  New  Jersey  Sprayed  Prod- 
ucts Co.,  Inc.,  Belleville,  N.  J.,  in  charge  of  development. 

*  *     * 

The  Porter-Cable  Machine  Co.,  Syracuse,  N.  Y.,  has  an- 
nounced the  death  of  Walter  A.  Ridings,  president  of  the  com- 
pany, on  October  17. 

*  *     * 

At  a  special  meeting  of  the  board  of  directors  of  Pro-phy-lac- 
tic  Brush  Co.,  Florence,  Mass.,  William  C.  Bird  was  elected 
president  of  the  organization.  Retiring  president  John  L.  John- 
ston, who  was  president  of  the  Lambert  Co.,  owner  of  the  entire 
capital  stock  of  Pro-phy-lac-tic  Co.,  was  elected  chairman  of  the 
board  of  the  latter-named  firm. 

*  *     * 

John  Lauterbach,  founder  of  the  Lauterbach  corporation, 
Toledo,  and  a  partner  with  his  son  in  the  firm  of  John  Lauter- 
bach &  Son,  Philadelphia,  died  on  November  1.  Mr.  Lauter- 
bach was  an  inventor  and  had  been  active  for  twenty-five  years 
in  the  plastics  field,  where  his  work  was  widely  known. 

*  *     * 

William  Volk  has  joined  the  insect  screen  sales  department, 


Lumitc  division  of  Chicopec  Mfg.  Corp..  and  will  have  his  head- 
quarters in  Columbus.  Ohio. 

*     *     * 

John  A.  Buckley,  formerly  associated  with  General  Electric 
Co.'s  lamp  department  at  Nela  Park.  Cleveland,  has  been  ap- 
pointed merchandise  sales  manager  for  the  company's  chemical 
department,  and  will  headquarter  in  Pittsfield.  Mass. 


I.  A.  Buckley 


L.  L.  Jones 


E.  M.  Linforth 


Lawrence  L.  Jones  has  been  named  superintendent  of  Gen- 
eral Electric's  new  factory  at  Anaheim,  Calif.,  which  is  to  be  . 
devoted  to  the  manufacture  of  Glyptal  alkyd  resins.     It  is  ex- 
pected that  production  at  the  new  plant  will  begin  before  the  end 
of  the  current  year. 

*  *     * 

Edward  M.  Linforth  has  become  head  of  the  design  section 
of  the  model  shop  at  Rohm  &  Haas'  plant  in  Bristol,  Pa.  He 
replaces  Henry  F.  Pearson,  who  resigned  September  1  to  act 
as  independent  design  consultant  on  applications  of  Plcxiglas. 

*  *     * 

Following  a  recent  meeting  of  its  board  of  directors,  Selec- 
tronic  Dispersions,  Inc.,  Montclair,  N.  J.,  has  announced  that 
William  C.  Appleton  has  become  president  and  a  director  of 
the  organization,  succeeding  Raymond  M.  Tierney,  resigned, 


More 


ACCURATE 
Service. 


and  we  mean  it  ...  BECAUSE  ...  in 
our  NEW  PLANT  we  have  loads  of  extra 
elbow  room  .  '.  .  AND  a  larger  staff  of 
competent  engineers  and  designers  .  .  . 
there  are  a  greater  number  of  expert  crafts- 
men .  .  .  AND  TOO  there  is  our  usual  high 
standard  of  quality  production  .  .  .  ALL 
UNDER  ONE  BIG  ROOF.  This  means 
.  .  .  more  ACCURATE  SERVICE  to  meet 
the  accumulated  needs  of  our  many  cus- 
tomers' Compression  and  Transfer  Molding 
Jobs  .  .  .  AND  PERHAPS  .  .  .  your  prob- 
lem too  .  .  .  why  not  call  us  to-day  .  . 
NO  OBLIGATION. 


ACCURATE 


MOLDING 
CORPORATION 


35-20    48th    AVENUE 
LONG  ISLAND  CITY  1 ,  N.  Y. 


DECEMBER  1946 


PLASTICS 


The  story  of  timber  in  the  Pacific  Northwest  is 
dramatic  and  well  known.  The  story  of  timber  and 
the  wood  plastics  industry  is  new . . .  and  vital! 

A  BACKLOG  Of  12  BILLION  FEET  OF  "PLASTIC 

TYPE"  TIMBER  IS  AVAILABLE  AT 

GRAYS  HARBOR  NOWI 

Think  of  the  tremendous  operational  advantages  of 
a  plant  located  in  the  GRAYS  HARBOR  area  in 
Washington  ...  a  surplus  of  raw  material  for  manu- 
facturing ...  a  huge  supply  of  industrial  water  .  .  . 
cheap  electric  power  .  .  .  efficient,  dependable  labor 
.  .  .  low  cost  transportation  by  land,  air  and  sea! 

Investigate  GRAYS  HARBOR  industrial  sites  for 
the  plastics  industry.  Detailed  information  pertinent 
to  your  specific  problems  is  available.  Well-financed 
civic  organizations  such  as  Grays  Harbor  Industries, 
IDC,  are  eager  to  cooperate  with  outside  capital  and 
management.  Write  to  the  address  below  for  infor- 
mation ...  or,  if  you  prefer,  a  personal  representative 
will  call  oa  you. 


GRHVS  HflRBOR 


Sponsored  By 

GRAYS  HARBOR  INDUSTRIES,  INC. 

ABERDEEN,  WASHINGTON 


who  lias  been  elected  secretary-treasurer.  Reuben  Kittenplan, 
former  secretary-treasurer,  will  remain  active  in  the  company's 
affairs.  Henry  Jenett  retains  the  office  of  vice  president  and 
general  manager.  Mr.  Applet  on  had  recently  resigned  from 
the  presidency  and  directorship  of  American  Viscose  Corp. 
*  *  » 

Herman  V.  Gaertner,  assistant  treasurer  of  the,  B.  F.  Good- 
rich Co.,  has  been  elected  controller  of  the  company.  following 
the  retirement  of  T.  B.  Tomkinson  which  \\ill  become  effective 
December  31,  1946. 


H.  V.  Gaertner  F.  C.  Zeisenheim 


R.  F.  Ohmer 


Fred  C.  Ziesenheim  has  been  appointed  sales  manager  of  the 
plastics  and  die  casting  machinery  divisions  of  Hydraulic  Press 
Mfg.  Co.,  Mi.  Gilead.  Ohio,  in  which  capacity  he  will  direct  the 
sales  and  assist  in  the  development  of  new  machines  for  these 
two  divisions. 

Robert  F.  Ohmer  has  been  appointed  vice  president  in  charge 
of  administration  for  the  company. 

*  *    * 

Dewey  &  Almy  Chemical  Co.  has  named  Stephen  B.  Neiley 
as  manager  of  the  company's  plant  at  Adams.  Ifus^  succeeding 
Paul  H.  Gill,  who  has  resigned. 

*  *     * 

George  A.  Hays  has  been  appointed  vice  president  and  gen- 
eral manager  of  the  Hinderliter  Tool  Co.,  Tulsa,  Okla.,  a  divi- 
sion of  H.  K.  Porter  Co.,  Inc. 

*  *    * 

The  Plaskon  Division,  Libbey-Owens-Ford  Glass  Co.,  has  an- 
nounced the  return  of  Carleton  Ellis,  Jr.,  from  service  in  the 
U.  S.  Navy,  to  the  post  of  manager  of  its  new  products  division. 
Dr.  Maurice  H.  Bigelow,  who  has  been  on  active  Army  duty, 
has  also  rejoined  the  Plaskon  Division  staff  as  director  of  tech- 
nical service. 


C.  Ellia.  Jr. 


Dr.  M.  H.  Biqelow 


M.  D.  Shenk 


Michael  D.  Shenk  has  been  appointed  chief  chemist  in  charge 
of  research  and  production  for  Peerless  Adhesive-  I'M  .  (  I 

•  •     • 

Heyden  Chemical  Corp.  New  York  City,  has  amumnred  the 
ap|Himtiiii-nt  of  Simon  Askin,  assistant  -  i  Assistant 

treasurer  of  the  company,  to  the  p»M  of  director  of  purchases. 

succeeding  Robert  P.  dould,  retired. 

•  •     • 

Albert  A.  Knauss.  formerly  of  the  Tulsa  district  office.  Allis- 
t  lialincrs  Mfg.  Co,  hav  Ix-comc  manager  of  the  n  unpam '»  Mini-t- 
in Memphis.  Trim.  Charles  F.  Codrington  has  tx-en  promoted 
from  assistant  to  the  manager,  to  the  position  of  sah  -  manager 
of  the  company's  blower  and  compressor  department. 

•  •     • 

Bjorkslen  laboratories,  Chicago,  has  announced  that  Dr.  C. 
Robert  Moulton  has  joined  thr  organisation's  staff,  in  the  ca- 
•v  of  research  associate. 


78 


i*  i.. \snrs 


I)i:<  KMKEK  1946 


overseas 


An  all-important  step  in  the  development  of  new  chemicals 
and  plastics,  from  oil,  has  just  been  taken  in  Great  Britain.  A 
new  $8,000,000  company,  called  Petrocarbon  Ltd.,  has  been 
formed  in  co-operation  with  the  British  Finance  Corporation 
for  Industry,  a  special  Government-sponsored  institution  estab- 
lished a  couple  of  years  ago  to  assist  in  the  reconstruction  of 
British  industry.  Operating  through  a  wholly-owned  subsidiary, 
named  Petrochemicals  Limited,  the  new  company  is  planning  to 
establish  in  the  Manchester  area,  within  the  next  few  years,  an 
industrial  estate  comprising  chemicals  and  plastics  factories 
grouped  around  a  central  plant  producing  basic  raw  materials 
by  the  Catarolc  process. 

Invented  by  the  world  famous  chemist,  Dr.  Chaim  Weizmann, 
and  brought  to  the  commercial  stage  by  Dr.  F.  Kind  of  the  Man- 
chester Oil  Refinery,  this  process  uses  naphtha  and  gas  oil  as 
its  principal  "filling  stock,"  and  is  claimed  to  be  the  only  method 
which  can  yield  the  full  range  of  aromatic  hydrocarbons  and 
olefinic  gases  which  form  the  basis  of  the  modern  chemical  in- 
dustry and  accordingly  of  the  plastics  industry. 

Plastics  fabrics,  synthetic  fibres,  varnishes,  rubbers,  dyestuffs, 
Pharmaceuticals,  cosmetics  and  insecticides  are  among  the  wide 
range  of  items  scheduled  for  production  in  the  Petrocarbon  group 
of  factories. 

Sugar-Based  Plastics 

According  to  the  annual  report  of  the  British  Colonial  Prod- 
ucts Research  Council,  a  semi-official  Governmental  body,  a  sig- 
nificant new  line  of  pure  chemical  research  has  opened  up  a  vast 
new  field  of  highly  promising,  plastics  raw  materials. 

Investigations  conducted  for  the  past  two  years  on  sucrose,  a 
cane  sugar  substance,  at  the  research  laboratories  of  Birmingham 
University's  Faculty  of  Science  by  Professor  Haworth,  eminent 
British  organic  chemist  and  Nobel  Prize  winner,  have  provided 
conclusive  evidence  that  cane  sugar  plantations  could  become, 
next  to  coal  and  oil,  an  outstanding  future  source  of  plastics  raw 
materials. 

Plastics  for  Display 

An  extension  in  the  usefulness  and  efficiency  of  transparent 
methyl  methacrylate  display  fittings  was  recently  demonstrated 
by  a  series  of  exhibition  shop  windows  in  London's  leading  West 
End  stores. 

Arranged  by  Fantom  Display  Ltd.,  in  co-operation  with 
George  Parnell  Ltd.,  and  others,  the  different  exhibits  tended  to 
create  an  illusion  of  being  suspended  in  the  air,  without  visible 
support. 

This  effect  was  achieved  through  the  application  of  precision 
engineering  methods  of  unit  construction  to  separate  fittings  and 
combinations. 

One  of  Britain's  foremost  plastics  designers,  Leori  Goodman, 
who  is  currently  experimenting  with  the  "edge  lighting"  and 
stereoscopic  effects  of  acrylic  resins,  appalled  by  the  inevitably 
high  material  waste  involved  in  methyl  methacrylate  display  de- 
signing, has  set  up  a  five-story  by-product  factory  for  the  ex- 
press purpose  of  making  cigarette  cases,  gift  boxes  and  orna- 
mental novelties  out  of  "left-overs." 

Staffed  by  plastics  experts  and  specialist  designers,  the  new 
factory  is  effectively  reducing  display  production  costs. 

British  movie  and  theatrical  producers,  too,  appear  to  be  mak- 
ing increasing  use  of  this  thermoplastic  for  film  and  stage  set- 
tings. 

Associated  British  Picture  Corporation's  latest  movie  ("Night 
Boat  to  Dublin"),  particularly,  makes  extensive  use  of  methyl 
metliacrylate  and  other  plastics  materials  for  harmonizing,  within 
a  general  color  scheme,  tables,  chairs,  wall  fixtures,  lighting  sys- 
tems, and  other  equipment. 

Similarly,  almost  the  whole  cast  of  a  new  stage  show,  cur- 


EEEEi 


WE   BOY 


Thermoplastic  Scrap- 
Rejected  Molded  Pieces 

_  Obsolete  Molding 
Powders-and  pay 
highest  prices 


WE    SEtt 


Reconditioned  molding 
^GUARANTEED 

to  lit  Y°ur  needs 


^^^ 

Your  scrap  ior  you 
WE  SPECIALIZE  in  cus- 
tom grinding,  magnetiz- 
ing, separating  and 

reworking. 


CELLULOSE  ACETATE    •    POLYSTYRENE    .    METHYL  METHACRUATE 

A.BAMBERGER 

CORPORATION 

44     HEWES     STREET,     BROOKLYN     11,     N.     Y. 

PHONE:  EVERGREEN  7-3887  •  CABLE.  CHEMPROD  BROOKLYN 


CELLULOSE  ACETO  •  BUTYRATE 


POLYVINYL  RESINS,  ETC. 


DECEMBER  1946 


PLASTICS 


79 


Plastics 


Jan.  25  thru  Jan  31 
Navy  Pier  •  Chicago 


•  The  SPE  Plastics  Show  will   be  the 
FIRST  held  in  Chicago. 

•  America's  leading  plastics  designers 
and  engineers  will  be  there! 

•  Special  educational  exhibits  and 
events  staged  expressly  by  SPE. 


SPE  Plastics  Show  Headquarters: 
Congress  Hotel,  Chicago.  500  Rooms 
Reserved!  Advance  reservations 
being  accepted. 


EXHIBITORS! 


Exhibit  spaces  still  available.  Write 

immediately  for  space  reservations, 

to: 

Society  of  Plastics  Engineers,  Inc. 

Theatre  Bldg. •Birmingham,  Mich. 


TOO    GOOD    TO    MISS! 


rently  running  at  one  of  London'*  West  End  theatre*,  wear* 
seamless  suits,  hats  and  footwear  made  from  a  new,  highly-pol- 
ished  bronze  colored  plastic-,  fabric  matt-rial. 

British   optical   instrument   makers  are  producing   U-iist 
binoculars,  cameras,  micron-opes  and  range-tinders,  made  fr.  mi 
methyl  tnethacrylatc  surface-coated  with  silica. 

And  an  enterprising  plastics  manufacturing  concern  has  pr.  •- 
duced  a  novel,  silica-hardened  12"-diameter  spherical  mirror 
from  the  same  thermoplastics  material,  for  which  it  claims  re- 
flecting properties  superior  to  those  of  glass,  as  well  as  con- 
siderable saving  in  grinding  and  shaping  operations. 

Acid-resistant  Plastics  Cement 

A  new  type  of  acid-resistant  plastics  powder  cement  is  \vi\\ 
being  manufactured  by  J.  H.  Sankey  &  Son,  Ltd.,  Ilford,  I- '.*-<  \  ; 
when  mixed  with  a  special  solution,  the  jxwder  forms  a  cement 
for  use  in  bedding  and  jointing  vitrified  bricks  and  tiles  in  the 
construction  of  acid-resistant  floors,  walls  and  tanks 

It  is  said  to  possess  exceptional  tensile  strength,  and  to  set  in 
12  hr,  withstanding  temperatures  up  to  1200°  C.  and  can  be 
stored  for  any  length  of  time  without  deterioration. 

Note  of  Caution 

A  warning  that  the  plastics  world  is  not  "just  around  the 
corner,"  or  the  plastics  industry  the  Eldorado  pictured  by  some 
enthusiasts,  was  recently  given  by  Sir  Herbert  Morgan,  chair- 
man of  the  British  Homophone  Company,  and  a  well-known 
commentator  on  British  plastics.  Addressing  shareholders  at  his 
company's  annual  general  meeting.  Sir  Herbert  emphasized  that 
the  industry's  future  lies  principally  in  branches  of  product  inn 
where  the  use  of  plastics  materials  lias  definite  competitive  or 
other  advantages  over  alternative  materials. 

Plastics  Developments  in  Australia 

.\  scanner  made  from  eight  specially  ground  sheets  of  I'frsffx 
acrylic  has  recently  been  constructed  for  the  Aircraft  Production 
Commission,  Australia,  by  Paul  &  Gray,  of  Melbourne,  makers 
of  acrylite  plastics.  Measuring  8'6"  long  by  50"  wide  and  3" 
deep,  it  is  designed  to  be  fitted  to  Lancaster  and  Tudor  bombers, 
and  is  said  to  be  the  largest  scanner  ever  made  from  1',-rsfc.r. 


"Perspex"  scanner  is  designed  lor  Australian  bombers 

The  same  firm  has  fabricated  a  radome  to  be  used  as  the  hous- 
ing for  the  oscillating  radar  antenna  for  aircraft.  Believed  to  be 
the  largest  ever  produced  in  the  Southern  hemisphere,  it  meas- 
ures 4'  -)"  in  diam.  liv  2'  deep,  with  a  flat  IS"  diam  at  hot  torn 

Originally  designed  as  a  "tear-drop."  the  difficulties  of  manu- 
facture caused  a  change  to  (he  form  of  a  sphere,  the  aerodynamic 
efficiency  of  which,  although  less  than  that  of  the  "tear-drop." 
was  not  sufficient  to  justify  the  expense  of  pnxlucing  the  orig- 
inally-planned type. 

The  material  usrd  «.i*  ,"  thick  1'trsftx  sheet ;  as  tlu-«c  »heet» 
measure  .18"  by  .%",  it  was  neci-*-ar\  to  join  lour  of  them  to- 
gether I iv  a  »p-cul  proc -ss  known  as  "dough  joining."  An 
•  «  t.iu>iii.il  container  w.i»  ^instructed  of  ' .',"  plywood  strengthened 
at  the  joints  to  provide  an  airtight  container.  The  -beet  «.<> 
clamped  to  the  container  by  <•  -clamps  and  a  coverplate.  \fter 
the  jointed  sheet  had  been  allowed  to  age,  it  wan  subjected  to  a 
temperature  of  MW  [•' ;  the  annealing  and  cooling  time  was 
approximately  I  lir.  When  the  r.nlome  was  cooled  the  flan 
trimmed  to  give  a  straight  side,  and  a  light  sandblast  finish  u.i- 
then  applied. 

The  radome  was  designed  by  J.  H.  Jordan  of  the  Council  of 
S.ii-nliii.  K.-i.mli.  mall-rial  ami I  dough-joining  supplied  by  Im- 
perial (  lii-mii al  IndiMrie.  ••!  \tistralia  It  New  /..il.ind  f  sn 


PI.  .\STI1  * 


I)K(  KMHKK  194(5 


Electric  Brush 

(Continued  from  page  26) 


1 


to  receive  the  clips  by  which  the  housing  is  attached  to  the 
gyrating  plate.  The  ready  removability  of  this  part  permits 
the  brush  to  be  easily  detached  for  convenience  in  cleaning. 

Nylon  bristles  with  their  qualities  of  long-lasting  firmness 
and  resistance  to  moisture  complete  the  product. 

Gyra  has  in  the  planning  stage  a  model  of  the  electric 
brush  with  a  decorative  acrylic  cover  and  brush  handle  at- 
tractively styled  for  feminine  use.  This  cover  is  the  only 
change  contemplated  for  the  new  model,  indicating  the  satis- 
factory performance  of  the  multiple  plastics  components. 

The  brush  is  to  be  distributed  by  specialty  and  depart- 
ment stores  throughout  the  country.  It  is  packaged  in  a 
heavy  gauge  acetate  film  display  box  which  fits  over  a  card- 
board base  faced  with  gilt  paper.  A  blue  cardboard  stand 
on  which  the  brush  rests  completes  a  package  making  use  of 
the  maroon  brush  back  and  the  blue  and  gold  of  the  carton 
to  display  the  product  to  advantage.  END 


f 


Precision  Molding  Phenolics 

(Continued  from  page  39) 


We  had  a  big,  unknown  factor  in  the  plastics  material, 
and  were  fully  aware  of  this.  We  mixed  and  rolled  every 
barrel  of  powder  before  preforming,  and  tried  to  maintain 
uniformity  in  every  operation.  In  spite  of  this,  when  we 
came  to  molding,  the  rejects  ran  high.  Despite  all  attempts 
to  improve  the  job  our  rejects  still  posed  a  problem.  We  felt 
that  everything  pointed  toward  non-uniformity  of  materials. 
This  was  finally  proved  when  one  supplier  came  through 
with  a  general  purpose  material  which  was  very  uniform. 
The  material  seemingly  was  similar  to  the  others  used,  but  it 
performed  much  better  and  reduced  the  number  of  rejects. 
We  do  not  know,  and  I  believe  that  even  the  supplier  did  not 
know  why  one  material  succeeded  and  others  failed.  Never- 
theless, this  was  proof  that  the  material  supplier  could  help 
the  industry,  even  if  material  prices  had  to  be  increased. 
When  dimensions  are  required,  material  cost  is  minor. 

Running  a  steady  cycle  both  on  preheating  and  curing 
was  found  to  be  of  extreme  importance.  All  presses  were 
operated  by  automatic  timers.  A  continuous  check  by  in- 
spectors warned  the  operator  whether  the  parts  were  chang- 
ing. The  operators  were  trained  to  change  dimensions  by 
various  methods.  By  a  combination  of  control  of  heat  and 
weight  this  6-7/16"  long  part  could  be  varied  up  to  .015"  in 
the  length. 

If  preforms  ran  heavy,  the  part  would  run  long  and  a  small 
portion  of  the  preform  was  broken  off  until  new  preforms 
were  made.  If  preforms  ran  light  a  tiny  preform  would  have 
to  be  added.  Almost  every  time  a  new  batch  of  material  was 
started  some  element  in  the  molding  cycle  had  to  be  adjusted. 
At  times  we  found  that  some  cavities  required  a  little  differ- 
ent weight  than  others.  This  could  be  caused  very  readily 
by  a  difference  in  the  temperature  in  two  cavities  side  by 
>idf,  if,  for  example,  steam  plates  became  water  logged  in 
places.  We  found,  also,  that  flash  escapes  were  slightly 
larger  than  those  in  the  other  cavities.  The  clearance  be- 
tween force  and  cavities  and  the  size  and  position  of  flash 
escapes  proved  to  be  very  important.  The  density  of  parts 
varied  with  these  factors. 

A  variation  in  temperature  or  preheating  time  usually 
would  affect  the  6.437"  dimension  instantly.  Various  types 
of  preheating  were  used.  The  electric  circulating  oven 
>o(.Miied  to  be  the  most  reliable.  The  average  preheat  time  to 
obtain  correct  shrinkage  was  10  inin  at  180°F.  Raising  the 


How  available  in  many 

beautiful  colors  and 

lor  every  purpose. 


Do  ml  acctplsuiistitittes. 
There  is  only  one  bltstk 
—CELLO.PLASTIC. 


Brings  New  Colorful  Beauty  and  Durable  Protection  to 
FLOORS*  WOODWORK*  WALLS  +  EXTERIORS 


Plastic  is  now  prepared  in 
liquid  paint  form  for  use  in 
home,  office,  store,  and  facto  ry . 
This  has  come  about  through 
the  formulation  of  synthetic 
resins  with  specially  processed 


oils  combined  with  the  finest 
paint  pigments.  ACello-Plastic 
product  is  available  for  almost 
any  type  of  finish  or  surface. 
Does  not  chip  or  Crack! 


BRILLIANT* SMOOTH*  TOUGH*  DUPABLE 

EOO    El  nrtDC    Cello-Plaslic  /transparent/  is  i  non-skid  plastic 
r\JK   TLWK9    finish  for  all  tvpes  of  floors.  This  amaring  new 

treatment  gives  floors  a  "cellophane-like"  Plastic  finish.  Eliminates  pores  that 
absorb  dirt,  thus  making  Boors  easy  to  clean.  Ideal  for  all  surfaces  includinu 
wood,  concrete,  linoleum,  asphalt,  tile  rubber,  composition,  etc.  Eliminates 
waxing  and  polishing.  Unexcelled  for  marine  use. 

EV  T  C  D  I  f\  D  This  modern  finish  is  a  severely  tested  product 
'V  I  C  I*  I  W  1%  tna|  surpasses  old  fashioned  type  house  paints. 
Picmenied  with  Titanium  Dioxide,  the  whitest  and  best  covering  pigment, 
combined  with  kettle  processed  linseed  oils  and  plastic  resins,  it  makes  a  rich, 
colorful,  lasting  coating.  Makes  homes  and  buildings  outstanding.  For  use  on 
wood,  stucco,  brick  or  shingle. 

IK!  T  C  D  I  f>  D     Brings  new  glamour  into  homes — protect  Boors, 
n  I  E  K  I  V/  K    woodwork,  furniture,  etc..  with  its  lonc-lasnng. 
"cellophane-like"  Plastic  finish.  Easy  10  apply— flows  smoothly— leaves  no 
brush  marks— self  leveling. 

Inquiries  from  Exporters  and  Dealers  Solicited 

Product  liability  underwritten  by  one  of  America's 
largest  insurance  companies. 


CELLO-PLASTIC  CHEMICAL  CO. 

417-419  BLVD.  OF  ALLIES,  PITTSBURGH  19,   PA. 


DECEMBER  1946 


PLASTtCS 


81 


temperature  in  the  oven  would  reduce  the  shrinkage,  lower- 
ing it  would  increase  shrinkage. 

High  frequency  preheating  was  also  used,  but  if  the  mate- 
rial were  heated  to  a  soft  condition  dimensions  varied  widely. 
In  preheating  to  a  high  temperature  in  the  high  frequency 
unit  the  shrinkage  was  increased.  This  wa-  <]iiite  natural 
a-  the  quick  preheat  did  not  dry  out  preform*  as  much  as  the 
dry  circulating  oven  did.  By  heating  preforms  more  slowly 
in  the  high  frequency  units  and  only  to  180°F  the  resulting 
dimension-  were  similar  to  those  obtained  from  the  dry  oven. 
The  shrinkage  in  these  parts  for  the  whole  length  and  the 
shrinkage  between  the  various  holes,  etc.,  was  found  to  be 
MTV  uniform.  If  a  flash  groove  appeared  to  permit  more 
material  to  escape  than  another,  it  always  showed  up  by  a 
slight  increase  in  shrinkage  between  the  holes  at  that  place. 

Many  millions  of  periscope  heads  were  molded  by  us  in 
this  way.  They  were  also  molded  successfully  by  several 
other  molders  on  the  same  dies. 

The  M10  periscope  head  was  approximately  7  in.  long  and 
was  molded  to  a  tolerance  of  (+.000; — .010).  This  part 
had  24,  6X36  holes  to  be  cored  for  self-tapping  screws.  The 
shape  of  the  part  was  such  that  we  were  forced  to  go  to 
transfer  molding  for  maintenance  reasons. 

Some  interesting  variations  showed  up  in  the  dimensions 
by  changing  the  speed  and  pressure  on  the  transfer  rams. 
While  using  conventional  electric  preheating  ovens  \\e 
could  vary  the  overall  length  by  only  .006"  to  .007".  We  had 
expected  a  shrinkage  of  .007"  to  .008"  per  in.  hut  found  that 
we  could  obtain  only  .005"  to  .006".  Going  to  high  fre- 
quency  preheat  we  managed  to  vary  this  7"  dimension  up  to 
.030".  Various  speeds  and  pressures  were  tried  to  find  the 
most  -table  conditions  for  molding.  The  idea  of  filling  a 
cavity  in  a  matter  of  2  or  3  sec  proved  most  undesirable 
in  thi-  case  as  the  -hrinkage  was  least  uniform.  For  best 


results  we  fdund  that  when  filling  cavities  in  15  to  IT  -<.v  on 
the  average,  the  dimension-  were  the  best.  It  wa-  nece—ary. 
at  times  to  employ  a  45  sec  transfer  time.  At  other  time-  we 
had  to  preheat  preforms  in  an  electric  oven  at  approximately 
150°F  before  placing  in  the  electronic  preheater:  as  the 
moisture  varies  in  the  preform,  the  loss  factor  changes  and 
this  variable  shows  up  in  the  use  of  electronic  preheating. 
In  this  case  the  operators  were  also  taught  how  to  change 
dimensions  when  required.  We  had  considerable  difficulty 
in  holding  this  7"  (+.000;— .010)  but  we  felt  that  if  we  had 
made  our  mold  to  a  lower  shrinkage  dimension  and  could 
have  used  dry  preheat  this  part  would  have  been  much  easier 
to  mold  to  size. 

When  it  comes  to  molding  to  close  tolerances  in  transfer 
molding  we  find  that  small  gates  are  desirable  only  on  small 
castings.  By  small  gates  we  refer  to  gate  thicknesses  of  .008" 
to  .020".  On  large  moldings  the  gate  size  must  be  large 
enough  to  be  able  to  distribute  the  back  pressure  evenly.  If 
part  of  the  material  starts  to  cure  before  the  cavity  is  full, 
the  shrinkage  will  vary  in  various  sections  of  the  part.  A- 
far  as  obtaining  any  snorter  cure  time  with  the  small  gates 
it  was  not  found  to  be  the  case,  probably  because  the  runners 
were  fairly  long. 

To  stabilize  dimensions  on  any  molded  part,  afterbaking 
is  used  to  a  great  extent.  Parts  are  placed  in  ovens  at  tem- 
peratures varying  with  the  type  of  material  used.  This 
process  improves  electrical  qualities  besides  accelerating 
warpage  and  aftershrinkage  which  will  always  occur  to  a 
certain  degree.  To  demonstrate  the  stability  possible,  sev- 
eral of  the  periscope  heads  mentioned  above  were  after- 
baked  and  were  given  very  careful  checks  at  intervals  over 
a  period  of  nearly  two  years.  Some  were  stored  at  room 
conditions,  others  placed  in  a  hot  boiler  room  and  some 
exposed  to  the  elements.  The  greatest  dimensional  change 


DESIGNED  FOR  EXPERIMENTAL  AND  PRODUCT  EXTRUDING 

Rugged  is  the  word  to  describe  this 
compact  and  highly  efficient  Royle 
continuous  extruding  machine.  It  em- 
braces all  of  the  characteristics  re- 
quired for  larger  and  heavier  extrusion 
processes. 

Primarily  designed  to  become  an  in- 
tegral part  of  laboratory  equipment — 
the  technician  can  be  sure  that  his 
experiments  will  parallel  actual  product 
extruding — the  Royle  #  I  is  an  efficient 
producer  of  such  commercial  products 
as  tubes,  rods,  fine  wire  insulation, 
mono-flament  and  thread  coating. 


JOHN     ROYLE     &     SONS 

fionttrtd    fk*    ConflniioiM    Eitrmion    frocut    In     1110 

PATERSON  3.  NEW  JERSEY 


tm»  Omt  (**• 
fhl««r»>   Ltd 
."<»".    tn|l>«4 
M...I    2410 


Horn*  OAr* 

II    M     Darii 

J.  W.  ' 


Akron.  OkU  LM  A 

I.   C.  dlmmur       H 
UNInnlty  >m 


Cll. 

.M.  in,  Im. 
LOtM    31*1 


I)K(  KMHKK   I1' Ml 


noted  during  this  test  amounted  to  .003"  on  a  7"  long  part. 
These  parts  were  molded  of  a  general  purpose  material. 
The  small  change  during  two  years  ageing  seems  incredible 
but  these  are  matters  of  record. 

To  repeat,  let  me  emphasize  that  precision  molding  is  not 
an  impossibility  but  such  precision  can  be  expected  only 
when  the  factors  of  part  design,  mold  design  and  construc- 
tion, uniformity  of  materials,  preheating,  correct  cycling  of 
operations  and  post  conditioning  are  properly  considered. 
With  the  automatic  molding  press  coming  into  its  own  so 
that  many  of  these  factors  are  uniformly  maintained  it  ap- 
pears that  a  large  part  of  the  responsibility  for  precision 
molding  will  rest  on  the  material  manufacturers.  END 


5111111 11 


End-Use  Testing 

{Continued  from  page  37) 


DEFORMATION  UNDER  HEAT  AND  PRESSURE:  A  plastics 
handbag  or  shoe,  when  placed  in  casual  contact  with  a  hot 
radiator,  will  melt,  for  that  is  the  nature  of  the  material — it 
is  thermoplastic.  But,  as  with  most  thermoplastics  in  general 
use  this  melting  point  can  be  raised  without  sacrifice  of  flexi- 
bility, by  means  of  technical  improvements. 

Fig.  1  illustrates  construction  and  operation  of  a  suggested 
testing  device.  An  aluminum  casting  as  shown  in  (a)  may 
fairly  be  assumed  to  represent  an  average  radiator  section. 
In  operation,  this  casting  is  placed  upon  an  electric  hot-plate 
having  thermostatic  control  accurate  to  within  ±3°  F.  This 
is  checked  at  point  (a)  by  means  of  a  thermocouple  leading 
to  a  potentiometer,  and  the  hot-plate  then  calibrated.  The 
heating  unit  should  be  used  in  conjunction  with  a  device 
carrying  suitable  test  pieces  of  the  material  6"  square,  which 
is  brought  in  contact  with  the  heating  element  for  a  pre- 
determined time.  The  sample  (d)  is  secured  against  the 
pad  (c)  by  means  of  clamps  (b)  against  stops  not  shown 
which  will  provide  even  tension  while  the  sample  is  under 
test.  The  pad  is  at  the  free  end  of  the  arm  (j)  which  has 
been  calibrated  in  Ib  and  oz  and  which  carries  a  weight  of 
established  mass  (k)  which  may  be  moved  along  the  arm 
(j)  and  firmly  clamped  in  position  where  desired.  The 
other  end  of  the  arm  (j)  is  pivoted  at  (i)  in  a  frictionless 
bearing  permitting  manual  movement  through  an  arc  of 
about  100°  from  the  horizontal  to  a  point  that  will  permit 
visual  inspection  of  the  sample  under  test. 

In  operation,  the  casting  (a)  is  brought  to  heat  (to  be 
determined)  and  checked  with  potentiometer.  Sample  is 
clamped  to  pad  while  arm  is  in  raised  position  (not  shown). 
Stop  watch  (1)  is  set  at  zero  and  is  started  by  trip-arm  (e) 
as  arm  is  placed  in  contact  with  heating  unit  (a),  where 
sample  is  left  for  predetermined  cycle.  At  the  end  of  this 
time,  arm  is  raised  and  visual  inspection  establishes  the 
absence  or  presence  of  deformation.  Cycle  is  repeated  until 
failure  is  noted.  Sample  may  then  be  rated  on  the  number  of 
cycles  endured  to  breakdown  or  on  the  time  required  to  effect 
the  same  result.  Thickness  of  sample  should  be  considered. 
OFFSETTING  :  Another  of  the  common  troubles  brought  to 
light  in  "returned  goods"  is  the  tendency  of  dyes,  paints,  pig- 
ments, etc.,  to  transfer  stains  to  light  colored  vinyl  film  or 
sheeting  after  prolonged  contact.  It  is  known  that  stains 
may  be  transferred  (offset)  from  painted  or  lacquered  sur- 
faces to  light  colored  vinyl  sheeting  without  visible  effect 
upon  the  paint.  Exactly  how  this  is  accomplished  is  not  quite 
clear  to  the  writer,  but  vapor  transfer  undoubtedly  takes 
place  between  the  two  surfaces,  inasmuch  as  they  both  con- 
tain volatiles  that  serve  to  keep  them  flexible.  Such  vapor  is 
usually  dissipated  into  the  atmosphere  but  when  a  plastics 
handbag  is  placed  upon  a  freshly  varnished  wooden  panel, 
there  seems  to  take  place  an  interchange  of  such  vapors  as 
one  or  both  of  the  surfaces  is  prepared  to  absorb.  Commonly, 


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vibration-free  on  needle,  tapered 
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and  is  lubricated  by  a  patented 
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trouble-free  operation. 

With  this  unit  all  holes  are  drilled 
at  one  pass,  and  valuable  time  is 
saved  by  the  elimination  of  in- 
dexing and  extra  handling.  It 
may  be  used  on  standard  drill 
presses,  or  furnished  as  a  com- 
plete hydraulic  machine  by  the 
factory. 

Another  time  saver,  as  well  as 
a  help  on  a  tedious  job,  is  chew- 
ing gum.  The  simple  act  of  chew- 
ing seems  to  make  the  work  go 
faster,  easier— helping  to  relieve 
worker's  fatigue— so  that  a  bet- 
ter piece  of  work  can  be  turned 
out  with  greater  safety.  Wrigley's 
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when  both  hands  are  busy— right 
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duced. 


You  can  get  complete  information  from 

Zagar  Tool,  Inc. 
23881  Lakeland  Blvd.,  Cleveland  11,  Ohio 


AA-99 


DECEMBER  1946 


PLASTICS 


83 


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this  results   in  unsightly  purple  or  yellow    stains  that  defy 
removal  without  tin-  destruction  of  the  surface  polish. 

An  approach  to  n  test  method  that  bears  directly  inx.n 
ond-use  is  somewhat  involved  in  this  case.  The  merchandise 
is  returned  to  the  store  with  no  reliable  record  of  how  the 
staining  occurred,  and  it  would  require  detailed  labor:u..i\ 
work  to  establish  the  active  vapor-borne  agent  responsible 
for  the  stain.  ( )nce  established,  this  would  reveal  little  more 
than  the  specific  chemical  responsible;  for  that  chemical  may 
exist  in  any  one  of  a  dozen  places  in  the  average  home,  from 
printing  inks  to  furniture  finishes.  It  seems  reasonable  to 
us  then,  that  an  approach  to  a  test  method,  in  this  case  (off- 
setting), lies  in  the  preparation  of  a  number  of  test  panels 
of  wood,  linoleum  and  metal  surfaces  which  are  finished 
with  typical  formulations  found  in  the  home.  Samples  of  the 
plastics  sheetings  under  test  would  be  clamped  or  weighted 
to  such  panels  for  predetermined  cycles  under  average  con- 
ditions of  temperature  and  humidity,  until  such  time  as  visual 
inspection  established  the  presence  of  offset  stains.  Or  an 
arbitrary  time  limit  may  be  established  at  which  point  those 
plastics  that  were  not  subject  to  offsetting  would  be  adjudged 
safe  and  so  described. 

I'I.ASTICIZER  MIGRATION  :  Sometimes  solvents  and  plasti- 
cizers  in  the  vinyl  sheeting  itself  can  damage  a  finely  finished 
piano,  radio  or  desk  if  a  plastics  handbag  is  left  lying  on 
them. 

The  test  panels  described  in  the  section  on  offsetting 
should  serve  as  well  to  establish  those  plastics  that  are  prone 
to  damage  furniture  through  plasticizers. 

DISCOLORATION  :  Several  instances  have  been  noted 
wherein  the  light-colored  plastics  patent  has  yellowed  with 
age.  In  one  example,  a  bag  made  up  of  three  stitched  panel- 
on  each  side,  the  center  panel  had  yellowed  considerably. 
This  had  undoubtedly  occurred  after  the  hag  had  been  made 
up,  and  yet  yellowing  had  not  occurred  on  either  of  the  end 
panels.  Erratic  compounding  is  indicated,  as  well  as  the 
tendency  of  some  light  plastics  patent  to  change  color  with 
time.  The  ASTM  describes  a  tentative  test  for  color-fast- 
ness of  plastics  wherein  samples  are  submitted  to  the  radia- 
tion of  a  (IK  sunlamp  of  uncertain  age.  This  test,  it  is  felt, 
has  little  merit,  as  has  already  lieen  pointed  out  to  the  Sl'l. 
since  the  radiation  from  such  a  lamp  varies  so  greatly  with 
its  age  as  to  render  the  results  inconclusive.  The  fadeometer. 
with  its  constant  source  of  radiation  (arc)  seems  to  be  a  far 
more  conclusive  test  method  and  one  which  has  given  11^ 
apparently  sound  results  over  long  periods. 

It  may  be  interesting  to  note  here  that  test  samples  of 
high-grade  luggage  leather  have  failed  in  the  fadeometer 
long  before  a  plastics  material  destined  for  the  same  end-use. 
It  is  suggested,  therefore,  that  the  fadeometer  In-  regarded 
as  providing  an  accelerated  color-fastness  test  for  pla-iu-- 
tilm  and  sheet  and  which.  |M>ssilily  with  some  allowance  for 
humidity,  approximates  end-use. 

i  HACKING:  Flex-te-ting  of  plastics  patents  indicate  that 
their  resistance  to  cracking  is  undoubtedly  higher  than  tin- 
old-fashioned  Japanned  patent  leather.  Yet  conditions  met 
with  in  end-use  indicate  that  even  this  may  not  IK-  good 
enough.  Examples  from  "returned-goods"  show  us  that 
some  formulations  fail  \i\ton  subjection  to  flexing  when  the 
article  is  brought  from  a  warm  room  into  zero  teiii|H-ratiire- 
in  the  course  of  normal  u-c. 

It  seems  logical  then  to  test  plastics  film  and  sheet  samples 
in  a  device  which  will   (lex   them  at  a  constant   rate  and 
iy  in  a  normal  atmosphere  as  regards  humidity,  but 
one  which  varies  in  teni|>erature  from  alxwt  100     1-   to  0 
Such  a  device  is  descnU-d  and  illustrated  in  this  article  . 

I  i  VMM  Mill  in     The  llanimability  of  plastics  film  used  in 

aprons,  drapes,  raincoats,  etc..  is  of  real  interest  and  should 

iblishcd  by  some  device  to  provide  .111  accurate  index 

of  this  trndeiu-y.     I  he  device  develo|H-d   for  testing  nap|>ed 

fabrics  is  truly  an  end  use  testing  machine,  and   it   is   sue. 


I*I..\ST1 1  * 


I)K(  KMHKK   1946 


gested  that  a  modification  of  this  same  machine  be  used  to 
rate  plastics  materials.  A  standard,  12"  sq  sample  of  the 
material  is  folded  in  a  jig  to  assume  a  standard  drape  which 
is  then  clamped  in  the  tester  where  it  is  ignited  by  a  con- 
trolled gas  flame.  The  time  differential  between  the  moment 
of  contact  with  the  flame  and  the  parting  of  a  cotton  thread 
ignited  by  the  burning  sample  may  be  used  as  the  rating. 

Flex-tester 

This  method  of  test  determines  the  number  of  flexions  that 
may  be  applied  to  a  specimen  of  flexible  plastics  film  in  an 
alternate  hot-cold  atmosphere  of  controlled  duration,  until 
failure  occurs. 

The  apparatus  consists  of  a  flexing  machine  bearing  the 
sample  under  test,  and  insulated  chamber  in  which  alternate 
hot  and  cold  atmospheric  changes  may  be  effected  which  are 
of  controlled  duration  in  time — the  entire  device  to  be  oper- 
ated in  a  room  of  normal  humidity. 

Fig.  2  shows  the  flexing  device  which  consists  of  mem- 
bers that  permit  of  constant  flexing  of  the  sample  without 
stretch,  but  which  accomplishes  a  folding  action  at  the  closed 
position.  Folded  sample  (a)  is  held  in  place  in  slots  in  both 
hammer  (d)  and  anvil  (b)  by  means  of  wedges  (e).  Flex- 
ing is  caused  by  the  movement  of  anvil  (b)  along  tie-rods 
(f ).  reciprocating  motion  being  transferred  from  crank  (h) 
through  connecting  rod  (g).  Electric  motor  (constant  speed 
induction  type)  bolted  to  frame  (1)  drives  crank  through 
worm  and  pinion.  Adjustment  of  the  nuts  (k),  etc.,  on  the 
tie-rods  (f)  permits  spacing  of  hammer  (d)  and  anvil  (b) 
so  that  at  the  closed  point  of  the  flexing  cycle  this  space  is  no 
less  than  four  times  as  thick  as  material  under  test  (a). 

Fig.  3  illustrates  a  method  of  standard  sample  prepara- 
tion, and  the  folding  action  of  the  sample  in  the  machine 
during  operation.  A  piece  of  film  or  sheeting  is  prepared  by 
stamping  out  of  stock  a  specimen  3j4"  long  by  2"  wide,  and 
this  is  folded  in  half  along  the  3y2"  axis,  without  creasing. 
As  many  such  samples  are  prepared  as  the  flexing  device 
can  accommodate.  They  are  secured  in  hammer  and  anvil 
(b,  d)  by  means  of  wedges  (e,  e),  or  similar  means.  The 
stroke  of  the  machine  is  constant,  but  the  distance  between 
the  hammer  (d),  and  the  anvil  (b),  is  adjusted  by  means  of 
the  tie-rod  nuts  on  the  anvil  end  of  the  machine  so  that  at 
the  top  of  the  "closed"  stroke,  it  is  no  less  than  four  times  the 
thickness  of  the  material  under  test. 

Fig.  4  illustrates  one  type  of  insulated  box  in  which  the 
device  described  in  Fig.  1  is  placed  during  the  test,  and  con- 
sists of  a  chamber  with  insulated  walls  (n),  having  two 
openings  (p,  q)  in  both  top  and  bottom  surfaces.  Top  open- 
ings are  not  shown.  Source  of  cold  air  (0°  F)  may  be  either 
a  container  of  dry  ice,  or  preferably  a  refrigerator  unit.  This 
source  is  connected  through  the  tube  (m)  to  one  of  the  holes 
in  the  top  of  chamber  (n.)  Insulated  slides  (u,  s)  are  so  con- 
structed that  they  slide  past  openings  on  top  and  bottom  of 
chamber  when  activated  by  means  of  beam  (t)  which  is 
powered  by  device  (w)  which  'controls  the  action  of  the 
beam  and  slides  to  provide  ventilation  cycles  of  predeter- 
mined length  and  frequency.  Heating  device  (r)  consists 
of  an  electric  heating  element  which  may  or  may  not  be  used 
in  conjunction  with  an  electric  blower,  and  which  is  con- 
nected to  one  of  the  holes  in  the  bottom  of  the  compartment 
(n).  In  the  position  shown  in  the  sketch  (3)  hot  air  from 
the  element  (r)  is  going  into  the  chamber  (n)  past  the 
rack  (o)  which  supports  the  flexing  device  shown  in  sketch 
(1),  but  which  is  not  shown  in  position  in  sketch  (3),  and 
out  through  the  hole  in  the  top  of  the  chamber  which  is  not 
connected  to  the  cold-air  source  (1).  At  the  end  of  this  hot 
air  cycle,  the  timing  device  (w)  actuates  the  slides  (s,  u) 
through  the  beam  (t)  so  that  the  top  slide  (s)  moves  to  the 
left,  closing  the  hole  through  which  the  heat  was  escaping 
and  the  hole  connecting  the  cold  air  source  when  the  cabinet 
is  open  to  offer  the  passage  of  cold  air  into  the  cabinet. 
At  the  same  time,  the  lower  slide  moves-to  the  right  closing 


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NATIONAL      DISTRIBUTORS 

H.  LEACH    MACHINERY    CO 

387     CHARLES    ST.  PROVIDENCE    4, 

AGENTS     IN      Alt      PRINCIPAL      CITIES 


DECEMBER  1946 


PLASTICS 


85 


LAMINATING  PRESS 

FOR  PRECISION  MOULDING  AND 
PRODUCTION  OF  SMALL  MOULDED 
PARTS  IN  LIMITED  QUANTITIES 

Built  to  commercial  press  standards  with  many  exclusive 
features  making  it  ideal  for  testing,  development,  laminat- 
ing and  actual  production  of 
plastic  products  on  small  jobs. 

Maximum  Opening  instantly 
available  by  means  of  synchro- 
nized handwheels,  without 
wrenches  or  special  tools. 

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contact  and  release  by 
means  of  vertical  hand- 
wheels. 

Handwheel  Pressure  Con- 
trol Valve  permits  pre-set- 
ting  to  any  desired  pressure 
or  gradual  change  of  pres- 
sure during  pressing  cycle. 

SPECIFICATIONS.  Platen  tin— 12"  x  12".  Ram  diam.— 7", 
3000  p.s.i.  developing  57  tons  pressure.  Daylight  opening  10". 
Steam  or  Electric  Hot  Plates  with  Chromalo>  Heaters  and  indi- 
vidual Fenwal  Thermostats  for  110  v.  A.C.  l'/2  H.  P.  Motor 
Hydraulic  Pumping  Unit.  Hand  operated  Hydraulic  Presses  in 
various  sizes  also  available. 

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the  hole  connected  to  the  heating  element,  and  opening  the 
hole  to  the  outer  atmosphere,  through  which  cold  air  flows 
from  the  chamber  by  mean>  of  convection. 

It  should  be  noted  that  the  Hex-tester  described  should 
not  operate  so  rapidly  as  to  build  up  an  appreciable  amount 
of  heat  in  the  material  under  test.  Such  a  rate  of  flexion  can 
be  determined  by  means  of  a  thermocouple  fastened  on  the 
inside  surface  of  the  material  which  will  register  operating 
temperatures  on  a  potentiometer.  The  thermocouple  she  mid 
be  attached  at  the  point  of  fold,  of  course.  The  machine 
should  then  be  set  to  operate  at  the  speed  at  which  such 
temperature  rise  will  not  introduce  an  unknown  destructive 
factor  into  the  test. 

There  is  no  doubt  that  further  research  in  "returned 
goods"  will  uncover  many  other  sources  of  trouble  with 
plastics  materials,  such  as  blooming,  crocking,  spewing,  etc. 
We  hope  the  foregoing  is  a  beginning  and  may  serve  to  stim- 
ulate discussion.  This  may  be  looked  upon  as  a  report  of 
work  in  progress, — no  more  and  no  less.  END 


Aircraft  Radar  Systems 

(Continued  from  page  29) 


»«!..,    t  OKI 


86 


These  figures  apply  to  the  3  cm  wavelength.  Actually,  the 
Polyfibre  radomes,  so  made,  had  a  transmission  higher  than 
90%  because  the  loss  tangent  of  molded  Polyfibre  is  less 
than  that  assumed  for  the  diagram  illustrated. 

The  loss  tangent  (roughly  equal  to  power  factor)  of  a 
material  determines  the  power  absorbed,  while  the  dielectric 
constant  determines  the  power  reflected  at  each  transition 
from  a  material  having  one  dielectric  constant  to  a  material 
having  a  different  dielectric  constant.  By  adjusting  the 
thickness  of  a  radome  wall  to  an  electrical  half  wavelength 
the  reflections  from  the  two  faces  cancel  out  and  give  tin- 
equivalent  of  zero  thickness,  except  for  the  power  absorbed 
when  the  loss  tangent  is  appreciable.  This  cancellation  ef- 
fect also  occurs  when  two  panels  of  moderate  thickness  are 
placed  about  a  quarter  wavelength  apart,  and  was  widely 
employed  in  the  double  wall  radomes  used  on  10  cm. 

Electrical  performance  is  closely  related  to  the  water  ab- 
sorption, thermal  expansion,  and  fungus  resistance  of  tin- 
plastics  employed.  The  dielectric  constant  of  many  radome 
materials  increases  about  ten  times  as  rapidly  as  the  weight 
when  exposed  to  water.  Even  more  serious  is  the  fact  that 
the  loss  tangent  increases  100  times  as  fast  as  the  weight. 
Thus,  only  materials  having  low  water  absorption  can  IK- 
satisfactorily  used  when  exposed  to  high  humidity  condi- 
tions. The  coefficient  of  thermal  expansion  of  the  radium- 
attachment  section  should  be  approximately  equal  to  that 
of  the  metal  part  to  which  it  is  attached;  by  choice  of  resin, 
laminating  material  and  the  percentage  of  resin  imprri;iu- 
tion,  this  can  usually  be  accomplished.  Most  copolyim-r 
resin  laminates,  even  with  cotton  filler,  will  not  support 
fungus  to  an  appreciable  degree  if  the  surface  is  non  IXMOUS. 

Sandwiches,  in  which  the  faces  are  made  of  high  strength 
laminates  and  with  a  core  of  low  density  material,  have  long 
been  under  consideration  as  aircraft  structures.  They  pro- 
vide the  highest  strength-weight  ratio  for  any  true  niono- 
coque  plastics  structure.  Sandwich  ty|x-  raciomcs,  repre- 
senting electrically  a  compromise  between  the  lull  \\.ivc 
length  construction  and  the  quarter-wave  spaced  double 
wall  construction,  found  wide  use  with  3  cm  radar  sy-tcin-. 
Provided  that  the  materials  used  have  sufficiently  low  los* 
tangents  to  keep  the  absorbed  power  loss  low.  and  have  low 
dielectric  constants  to  give  adequate  manufacturing  t-Oi-i 
am-i-s.  the  choice  of  plastics  can  IK-  made  on  a  basis  of 
structure  and  weight.  I-'or  given  materials  in  tin-  eon  ami 
ami  conditions  existing  with  rcsjK-ct  to  the  radar 
,  an  optimum  core  thickness  is  closely  related  !• 


I)K(  KMBKK  1946 


STI  t  * 


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s 
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a: 


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<      O     U.     t— 


BUSINESS    REPLY    ENVELOPE 

Pint  Claw  Permit  No.  336}     Sec.  510.  P.  L.  &  R.         CblcMo.  1U. 


plastics 

185  N.  WABASH  AVE. 
CHICAGO   1,   ILLINOIS 


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ELECTRICAL       THICKNESS 

* 

Power  transmission  vs.  electrical  thickness  (loss  tangent 
=  0.036  assumed).  "\"  =  wavelength;  "T"  =  thickness 
in  same  units  as  wavelengths;  "e"  =  dielectric  constant 

skin  thickness.  The  skin  thickness  may  be  varied  over  a 
fairly  wide  range  to  suit  structural  requirements. 

Where  it  is  possible  to  analyze  the  stresses  in  a  radome, 
the  conventional  methods  of  structural  design  may  be  ap- 
plied using  design  constants  obtained  on  samples  of  the 
materials  over  the  entire  range  of  operating  conditions  an- 
ticipated. All  too  often,  however,  experience  and  experi- 
mentation are  the  principal  design  essentials  because  of  the 
difficulty  in  analyzing  monocoque  structures.  It  is  neces- 
sary to  consider  the  strength  and  stiffness  of  any  design 
at  the  temperatures  encountered  in  service  use. 

In  the  manufacture  of  radomes  certain  processes  must  be 
controlled  more  closely  than  those  of  other  aircraft  parts. 
The  percentage  of  resin  impregnation  must  be  watched  and 
impregnated  fabric  used  immediately  or  stored  for  a  limited 
time  under  close  temperature  control  to  prevent  loss  of 
plastics  monomer  and  a  consequent  increase  in  the  dielectric 
constant  of  the  finished  laminate.  The  curing  cycle  must 
be  exactly  timed  for  the  same  reason. 

Precise  thickness  is  of  crucial  importance  in  radome 
design.  Accuracy  here  can  eliminate  reflected  power  loss 
by  cancellation  in  many  cases,  and  thus  the  thickness  of 
sandwich  skins  (even  to  the  point  of  limiting  fabric  over- 
lays to  measured  values)  and  the  overall  thickness  must  be 
carefully  checked.  In  the  finishing  process  the  amount  and 
type  of  paint  must  be  carefully  watched,  so  that  the  electrical 
performance  will  not  be  impaired.  (Zinc  chromate  has 
been  found  to  be  unsuitable  for  this  aircraft  part.)  The 
completed  radome  should  be  free  of  local  defects,  or  soft 
spots  and  should  present  an  appearance  which  inspires  pilot 
confidence. 

The  testing  of  power  transmission,  power  reflection  and 
antennae  pattern,  with  and  without  the  radome,  serve  to 
determine  how  nearly  invisible  the  radome  is  to  the  radar 
energy  passing  through.  Final  ground  testing  is  accom- 
plished by  photographs  of  the  scope,  or  radar  screen,  for 
system  operation  with,  or  without,  the  radome  over  the 
antenna.  With  a  poor  radome  most  of  the  distant  targets 
or  points  seen  by  the  radar  will  disappear.  Complete 
weatherometer  and  mechanical  tests  are  applied  to  deter- 
mine structural  adequacy.  Finally,  a  flight  test  with  the 
radome  installed  and  complete  with  gun  blasts  from  nearby 
armament  will  give  proof  of  structural  strength.  System 
performance  may  be  checked  during  the  flight  although 
there  is  no  absolute  standard  of  comparison  possible,  for  the 
radome  cannot  be  removed  in  flight  to  see  whether  it  is 
causing  targets  to  be  lost. 

With  the  radomes  available  today,  particularly  those 
fabricated  of  Fiberglas  honeycomb  sandwich  construction, 
it  is  possible  to  step  up  airplane  performance  by  covering 
all  antennae  with  streamlined  housings  or  by  sinking  the 
antennae  inside  the  airplane  behind  sturdy  laminated  sec- 
tions. A  military  aircraft  may  have  the  following  electrical 
equipment,  each  requiring  a  plastics  housing  or  section: 


TO  YOUR  SPECIFICATIONS 

For  over  forty  years  we  have  been  leaders  in  the  design 
and  manufacture  of  component  parts  for  leading 
Refrigerator,  Stove,  Furniture,  Appliance  and  Cabinet 
industries.  We  specialize  in  custom  molding  by  the 
injection,  compression  or  transfer  method  in  any  ther- 
mosetting  or  thermoplastic  material.  A  complete  ser- 
vice from  one  source  to  serve  your  needs  —  at  no 
extra  cost. 


RESEARCH  — 

Highly  experienc- 
ed research  engi- 
neers to  deter- 
mine the  material  best  suited 
for  your  needs  as  to  strength, 
utility  and  beauty. 


ENGINEERING— 
Here  is  where  the 
correct  tools,  pre- 
cision dies  and 
molds  are  developed  to  pro- 
duce the  best  job,  efficiently 
and  economically. 


MOLDING  —  A 
complete  depart- 
ment equipped 
with  the  latest 
and  most  modern  presses  and 
molding  equipment  —  for 
Injection,  Compression  or 
Transfer  molding. 


DESIGN  —  A  thor- 
ough study  is  made 
as  to  the  utility, 
shape  and  color  of 
the  plastic  part  that  will  best 
harmonize  with  the  style  and 
design  of  your  product. 


TOOL  AND  MOLD 
MAKING  —  This 
department,  manned 
by  expert  crafts- 
men, makes  the  necessary 
tools  and  molds  to  produce 
the  finished  product. 


INSPECTION 
AND  SHIPPING 

Each  individual 
piece  is  carefully 
inspected  for  uniformity,  col- 
or and  finish.  All  parts  arc 
carefully  wrapped  and  packed 
for  utmost  protection. 


//  you  are  planning  the  use  of  plastic  parts  in  your 
products,  it  will  be  advantageous  for  you  to  investi- 
gate our  complete  service.  Write  or  phone  us  about 
your  needs. 


NATIONAL   LOCK 
COMPANY 

Plastics   Division 

ROCKFORD,    ILLINOIS 


DECEMBER  1946 


PLASTICS 


87 


WATER  WHITE  TRANSPARENT 

Sticks  everything  to  everything.  Dries  fast  but  not  too 
fast  for  handling  large  pieces.  Now  used  extensively 
in  such  industries  as  handbags,  display  fixtures,  deco- 
rating, etc. 

A  mild  type  of  adhesive,  perfect  for  cementing  mirrors 
to  plastic  without  affecting  either,  also  leather,  cloth 
or  wood  to  plastics  or  to  each  other. 


TRIAL  GALLON 

Write  or  vv/'re 


.  R 


^r  B 


ORDER; 


SCHWARTZ  CHEMICAL  CO.,  Inc. 

326-328  West  70  Street,  New  York  23,  N.  Y. 


This  gauze  pad  dispenser,  made 
for  one  of  the  leading  surgical 
supply  houses,  illustrates  one  of 
the  many  unusual  plastic  dis- 
play assignments  executed  by 
Printloid. 

Consult  with  our  design  staff 
now. 


«  T  •  • 


M    .     .     .     . 


DIPT    P 
I)  MERCER  STREET.  NEW  YORK  12.  N  T 

r  •   j  •          PI    •  .  >    / « 


t»ili" 


Dielectric  Constant  and  Loss  Tangent 

Dielectric  Constant  Loss  Tangent 


Po/yfibre,  0.8  density 2.0 0.002 

Polystyrene,  clear 2.6 0.002 

Methyl  methacrylate 2.7 0.004 

Alkyd-styrene  copolymer,  clear 2.8 0.01 

Alkyd-styrene  Fibergfos  laminate 3.7 0.0 1  5 

Phenolic  or  orea  Fibergfai  laminate 5.0 0.06 


Meawri 
if  moitf. 


made  at  approximately  3  cm.  Individual  tamplei  may  vary,  particularly 


Radar  Altimeter,  Identification  Friend  or  Foe,  Navigation 
Radar,  Gunnery  k;t<l;ir,  VHF  communications,  anil  three  en- 
four  Radio  Countcrmeasures  systems.  One  may  well  ask 
why  the  entire  airplane,  or  at  least  a  large  part  of  it.  U  not 
made  of  plastics  with  Miitable  electrical  properties  and  de- 
sign  of  structure  ? 

While  much  can  and  is  being  done  to  use  available  ma- 
terials to  make  such  large  airplane  sections  perform  an  elec- 
trical housing  function,  future  developments  in  low  ]>re-- 
sure  laminating  materials  and  techniques  are  expected  to 
aid  substantially  in  advancing  this  work.  High  strength, 
together  with  reduced  weight,  low  dielectric  constant,  and  a 
low  loss  tangent  in  a  plastics  which  will  withstand  high  tem- 
peratures is  needed.  Improvements  in  bearing  strength  and 
means  of  attachment  will  go  far  to  remove  the  weight 
penalty  associated  with  plastics  in  the  minds  of  some  aero- 
nautical engineers. 

While  radomes  in  the  past  have  been  primarily  a  feature 
of  military  aircraft  and  may  be  expected  to  be  increasingly 
important  in  the  new  military  aircraft  they  will  undoubtedly 
prove  to  be  a  common  feature  of  commercial  aircraft.  Such 
aircraft  with  Radar  Altimeters,  Navigation  Radar,  and  tin- 
recently  announced  Teleran  and  Stratovision  are  indicative 
of  a  constant  peacetime  requirement.  FNH 


Radio  Dials 

(Continued  from  page  40) 


88 


The  molding,  which  did  not  incorporate  runners  or  fates 
from  the  sprue  to  the  piece  part,  was  done  on  an  eight-oz 
Reed-Prentice  machine,  using  a  super  plunger  in  No.  5 
setting.  Injection  pressure  was  9,000  psi.  The  only  finish- 
ing required  was  the  removal  of  the  sprue. 

Painting  of  the  piece,  which  weighs  4y2  oz,  also  posed 
somewhat  of  a  problem.  The  lower  portion  had  to  match 
perfectly  the  meter  case  made  of  molded  black  phenolic 
with  a  rigid  vinyl  window.  The  crystal  clear  upper  por- 
tion and  the  entire  vernier  indicator  window  were  market! 
and  the  matte  surface  sprayed  with  optical  black  paint.  A 
coat  of  clear,  non-gloss  lacquer  was  then  sprayed  on  to 
provide  added  surface  protection. 

Subsequently  the  ma«king  was  removed  from  the  upper 
portion  of  the  vernier  indicator  window  (which  serve-  t" 
illuminate  the  vernier  indicator)  and  from  the  clear  rim  of 
the  upper  part  of  the  escutcheon.  These  areas  were  thru 
sprayed  with  a  thin  translucent  coating  of  green.  This. 
color  was  chosen  to  match  the  green  vinyl  main  tuning  ami 
band  spread  dials. 

The  Hallicrafters  engineers  point  to  the  F.chophone  - 
of  new  home  receivers  as  evidence  of  the  accelerated  use  of 
plastics.     Plastics  components  in  their  radio  equipment  in 
I'Md  has  increased  l?d';   over  the  quantity  used  in  l'»41. 

The  development  of  the  tuning  dial  escutcheon  lias  been 
larticularly  rewarding  to  the  Hallicrafters  ( '«.  IM-I.M. 
realisation  of  lower  product  inn  costs,  simplicity  of  handling 
iim-.|..  >ns  on  the  production  line,  excellent  trans- 

parent qualities   for  dial  windows,  and  adherence  to  clo-i 
tolerances.  '  N|1 


DECKMKKK  1946 


Phenolics  Replace 
Sheet  Steel 


Smooth    lines,    absence   of    rough    edges   of    phenolic    cur- 
rency  tray,   offer  sharp   contrast   to   the   old   steel   version 


Molding  plastics  cash  box  saves 
time  used  in  steel  fabrication 


HERETOFORE,  the  utilization  of  plastics  for  office 
supplies  has,  in  most  cases,  been  limited  to  desk-top 
accessories  where  unusual  decorative  appeal  was  essential. 
Today,  however,  steps  are  being  taken  toward  a  wider  use 
of  plastics  in  utilitarian  supplies  and  heavy  duty  office  equip- 
ment. 

A  step  in  this  direction  has  been  taken  in  the  production 
of  a  series  of  phenol  formaldehyde  cash  box  currency  trays 
by  Moldmaster,  Inc.,  an  associate  firm  of  the  Art  Steel 
Corporation  of  New  York. 

Compression  molded  of  black  phenolic  by  the  Boonton 
Molding  Company,  Boonton,  New  Jersey,  the  Moldmaster 
trays  offer  a  number  of  distinct  advantages  over  the  old 
steel  trays.  Vastly  improved  appearance  has  been  achieved 
in  the  clean-cut  form  and  the  pleasing  color  contrast  of  the 
black  to  the  futura  grey  of  the  steel  cash  box  into  which  the 
tray  fits.  The  tray  is  warm  to  the  touch,  smoothly  con- 
toured, and  presents  no 'sharp  corners  or  rough  edges.  It 
does  not  require  painting  nor  is  it  subject  to  oxidation  as 
was  the  steel  tray.  And  within  the  same  dimensional  limits, 
the  new  tray  offers  10  to  12%  greater  capacity. 

Higher  Production  Cost 

The  production  cost  of  the  plastics  tray  is  approximately 
60%  higher  than  its  predecessor.  The  additional  cost,  in 
this  instance,  was  justified  by  improved  appearance  and 
durability  in  addition  to  the  release  of  the  Art  Steel  Com- 
pany's steel  fabricating  facilities  to  other  production — an 
important  consideration  for  a  plant  engaged  in  producing 
a  large  variety  of  office  equipment. 

An  idea  of  the  production  facilities  freed  by  this  one 
conversion  from  steel  to  plastics  may  be  gained  from  the  fact 
that,  besides  the  painting  job,  almost  40  individual  opera- 
tions are  involved  in  the  manufacture  of  the  steel  tray, 
among  them  blanking,  notching,  bending,  folding,  crimping 
and  welding. 

The  plastics  currency  trays  represent  not  only  the  im- 
provement of  an  individual  product,  but  also  the  start  of  an 
ambitious  program  introducing  plastics  in  utilitarian  office 
equipment.  Planned  by  Moldmaster,  for  merchandising 
through  Art  Steel,  a  number  of  projects  are  already  in  the 
pre-production  testing  stage  and  many  more  are  in  blue- 
print. Joseph  Burger,  head  of  both  firms,  is  of  the  opinion 
that  business  equipment,  to  meet  modernization  trends  and 
demands,  must  envision  greater  plastics  utilization.  END 


advantages 
Missouri: 


251   new  corporations 
nine  months  of  1 


Skilled  native  labor 


JRIIICM    •• 

Excellent  transportation 
facilities 


Rich  markets 

Wealth  of  naturalresources 

Low  cost  power 

350  communities  eager  to 

cooperate 

Whether  you're 

_  1  _.**   f\r 


DECEMBER  1946 


PLASTICS 


89 


The  Ideal  Machine 

for  PLASTIC  PARTS 

Excellent  for  Short-Run 

Production  and 
Experimental  Work 

The  All-Purpose  S-K-W  Press  may  be  the 
answer  to  your  production  problem.  Can 
be  used  for  hundreds  of  molding  needs. 
Produces  both  plastic  and  rubber  parts. 
Operates  under  varying  degrees  of  pres- 
sure and  temperature  for  testing  and 
checking  materials,  parts  design,  mold 
design,  and  for  production  of  many 
kinds  of  short-run  jobs.  The  ideal  ma- 
chine for  manufacturers,  custom  molders, 
laboratories,  home  workshops,  colleges, 
etc  Compact,  sturdy,  durable.  Operates 
qukkly,  accurately,  economically.  At- 
tractively priced.  Pays  for  Itself  In  a 
short  time. 

Platen    area    approximately    20    sq.    in. 
Sue   of   press   9'/j"xl4'x26"   high.    Ram 
pressure    up    to    8    tons. 
Write  Jor  Complete  Information 

CLARENDON  MFG.  CO. 

DIPT.  Z-D,   176   W.   ADAMS   STREET,    CHICAGO   3,   ILLINOIS 
REPRESENTATIVES   WANTED 


PROTECT  YOUR  HOME  PROM 

TUBERCULOSIS 


BUY 
CHRISTMflS-SEfiLS 


The  fight  against  tuberculosis  It  not 
wen  .  .  .  and  on*  of  the  mott  effec- 
tive means  you  can  use  to  join  th« 
fight  Ii  to  buy  and  uic  Christmas 
Seals.  The  funds  will  be  of  direct  help 


New  injection  machine  handles  wide  range  oi  small  parts 


2  Oz.  Infection  Press 


THE  FIRST  production  unit  under  its  own  name  was 
recently  presented  by  Hydraulic  Machinery,  Inc., 
Detroit,  Mich.,  to  the  plastics  industry.  Harry  L.  Wise, 
president,  claims  that  his  company's  2  oz.  injection  molding 
machine  has  several  novel  features  so  designed  by  Warren 
Gross  that  tyros  in  the  plastics  field  can  operate  the  machine 
easily  and  successfully.  • 

Particular  emphasis  is  placed  on  two  electronic  controllers 
which  regulate  chamber  and  nozzle  heat.  The  machine  panel 
upon  which  they  are  mounted  is  not  affected  by  machine 
vibration  and  is  said  to  guarantee  accuracy  of  ±2".  Cham- 
ber and  nozzle  temperatures  can  be  held  indefinitely. 

Mold  clamping  is  effected  by  using  toggle  action.  The 
mold  in  closed  position  conies  against  positive  stops  to  pre- 
vent misalignment.  They  are  made  of  steel  castings  and 
are  designed  with  a  safety  factor  of  6:1.  Platens  are  cast 
of  semi-cast  iron  and  are  stress  analyzed  with  a  safety  factor 
of  4:1.  There  is  a  \2'//'  clearance  between  the  strain  bars 
both  in  top  and  side-.  Platens  are  said  to  be  easily  adjust- 
able to  hold  a  die  of  a  minimum  of  $]/}"  to  a  max.  of  9J4". 

The  press  features  a  metering  device  which  is  designed 
to  allow  the  correct  amount  of  material  to  enter  the  injec- 
tion cylinder  and  which  is  easily  adjustable  for  different 
types  of  molds.  Maximum  pressure  of  the  injection  plunger 
is  28,400  psi  when  operating  at  1000  psi  line  pressures  and 
the  injection  stroke  has  a  3  sec  cycle  for  the  full  8  in. 

All  controls  arc  electric  and  are  located  in  one  panel 
including  switch  relays,  timers,  temperature  controllers  and 
motor  starter.  The  machine  is  so  dc Mailed  that  molds  or  the 
injection  cylinder  will  not  work  while  either  safety  gate  is 
open.  A  -ai'ety  -witch  is  located  on  the  front  platen  and  is 
actuated  by  the  closing  of  the  mold.  I'nlcss  nil  switch  is 
closed  the  injection  cylinder  will  not  operate. 

Although  the  machine  is  rated  at  2  oz,  it  has  actually  been 
designed  and  built  with  a  5<>fc  overload  capacity,  so  that  it 
is  capable  of  handling  a  wide  range  of  small  plastics  parts 
and  products.  It  appears  to  be  an.  ideal  machine  for  the 
production  of  small  units  of  automotive  body  ap|M>intmcnts, 
noveltie-.  not  inns  and  costume  ac. 

The  com|iany  plans  to  put  the  new  machine  into  immediate 
product ii MI.  i  n 


90 


I'l.ASTH  * 


I)K(  KMBKR  1946 


Heat  Sealing  Plastics  Films 

(Continued  from  page  55) 


1 


to  be  used  with  conventional  electrodes.  Construction  of  this 
type  is,  of  course,  not  very  rugged  and  does  not  stand  up 
well  in  production.  However,  there  are  instances  where  it  is 
the  only  means  of  doing  the  job. 

An  electrode  system  and  plastics  film  represent  a  load  of 
considerable  diversity.  Electrical  capacities  of  loads  found 
in  practical  jobs  range  from  5  to  500  mmf.  The  effective 
electrical  capacity  of  the  load  generally  increases  during  the 
heating  cycle.  This  effect  is  due  in  part  to  the  increase  of 
dielectric  constant  with  temperature,  which  occurs  in  most 
thermoplastic  materials.  The  principal  increase  in  capacity, 
however,  is  due  to  the  softening  of  the  material,  which  per- 
mits the  electrodes  to  move  closer  together. 

The  dielectric  strength  of  materials  at  high  frequency  is 
only  a  small  fraction  of  the  value  for  low  frequency.  No 
direct  relationship  seems  to  exist  between  the  dielectric 
strength  at  low  and  high  frequencies.  Materials  with  low 
power  factor  have  a  considerably  better  dielectric  strength 
at  high  frequency  than  those  of  high  power  factor.  The 
amount  of  individual  variation  which  exists  among  samples 
of  the  same  material  is  considerable.  For  example :  at  30  me 
two  pieces  of  .006"  Vinylite  will  sometimes  withstand  an  in- 
stantaneous voltage  of  1000  volts.  In  a  production  setup 
the  voltage  may  be  adjusted  to  about  600,  yet  occasional 
arc-through  will  occur.  Most  commercial  material  contains 
occasional  air  bubbles  and  pin  holes  and  if  these  defects  oc- 
cur too  frequently  arc-through  will  be  encountered  in  pro- 
duction. 

A  minimum  power  input  per  unit  area  is  necessary  to  pro- 
duce welds  in  any  time  (unless  foil  electrodes  are  used). 
It  follows  therefore  that  a  minimum  voltage  must  be  im- 
pressed across  the  electrodes.  At  a  given  voltage  and  fre- 
quency, the  power  absorbed  by  a  load  is  inversely  propor- 
tional to  the  distance  between  the  electrodes.  But  as  shown 
previously,  the  minimum  input  power  is  also  roughly  in- 
versely proportional  to  the  gauge  of  material  being  welded. 
On  this  basis  we  may  conclude  the  following:  The  minimum 
voltage  necessary  for  welding  is  almost  independent  of  the 
gauge  material  used.  (This  of  course  holds  only  for  the 
same  material  and  fairly  constant  frequency.)  For  Vinylite 
this  minimum  voltage  is  about  500  volts  at  25  me.  The 
value  for  Saran  is  somewhat  lower,  and  for  acetate,  some- 
what higher. 

It  is  now  possible  to  set  up  desirable  criteria  for  the  cir- 
cuit delivering  power  to  the  electrodes. 

The  following  is  to  be  accomplished: 

1.  Voltage  is  to  be  supplied  to  an  electrode  system  which 
may  range  in  capacity  from  5  to  500  mmf. 

2.  The  voltage  applied  to  this  system  shall  be  readily  con- 
trollable, and  be  capable  of  adjustment  from  a  minimum  of 
400  volts  to  a  maximum  of  1000  volts  or  more,  for  all  pos- 
sible values  of  load  capacity. 

3.  Small  changes  in  load  capacity  shall  not  have  a  drastic 
effect  on  the  voltage  applied  to  the  electrodes. 

4.  A  large  increase  in  load  capacity  shall  cause  a  sub- 
stantial reduction  in  electrode  voltage. 

The  circuit  shown  in  Fig.  3  is  capable  of  fulfilling  all  the 
conditions  set.  By  adding  a  permanent  fixed  capacity  to  50 
mmf  across  the  load,  the  ratio  of  possible  load  capacities 
has  been  decreased  considerably.  It  is  now  55  to  550  mmf. 
Let  us  assume  that  the  tank  voltage  in  a  practical  circuit  is 
3000  volts.  Then  the  minimum  capacity  in  series  with  the 
load  will  be  8.5  mmf  while  the  maximum  capacity  for  the 
series  condenser  is  225  mmf. 

This  large  capacity  ratio  cannot  readily  be  handled  with 
a  single  condenser,  but  calls  for  a  variable  condenser  which 


Rayco  Fillers  are 


to  suit  your  needs  EXACTLY 

So  much  depends  upon  getting 
the  filler  just  right  for  each  item 
to  be  molded!  Our  pioneering 
research  has  demonstrated  that 
small  adjustments  carefully  con- 
trolled,  can  yield  substantial  ben- 
efits in  the  finished  article.  We  make  GOOD 
fillers.  To  them  we  add  the  research  counsel  en- 
abling you  to  get  the  BEST  results. 

Request  Free  Working  Samples 


FILFLOC     Pure  Cotton  flock        *FABRIFIL  Uniformlyprepared 
of  surpassing  clean-  macerated  cotton 

liness  and  uniformity.  fabric  for  extra  strength. 

"Trademark   Reg.   No.  423571. 


RAYON  PROCESSING  CO. 


• 


gotten 


45  TREMONT  ST. 


CENTRAL  FALLS.  RHODE  ISLAND 


DECEMBER  1946 


PLASTICS 


91 


•^NORTHERN 

It's  your  custom  molder's  responsibility.  He  must  make 
the  part  right  ...  or  the  product  is  wrong!  When  you 
specify  Northern  you  gain  the  advantage  of  more  than 
37  years  of  experience  in  producing  plastics  for  all  type 
assemblies.  You  are  assured  of  precision  and  uniformity 
for  your  plastic  part,  which  means  quicker,  cleaner  as- 
sembly ...  a  better  all-over  job. 


INDUSTRIAL  CHEMICAL  CO. 

38    Years   of   Plastic    Molding   Experience 
7-11   ElKINS  ST.,  SO.   BOSTON  27,  MAiS. 


m  BOX 

THAT'S  NEVER 
THROWN  AWAY 


SENSATIONAL-  N£W 

WE  are  now  granting  license 
and  furnishing  equipment  for 
making  this  sensational  new 
folded  plastic  box. 

Protection,  reuse  and  display  com- 
bine in  these  rigid  boxes  that  are 
made  from  cellulose  acetate  or  viny- 
lite  and  which  require  no  cement  or 
solvent  to  hold  them  together. 

THE  BOX  THArS  NEVER  THROWN  AWAY 

JOHN  H.  OXLEY  co. 


8  CHURCH  STREET 

WATERTOWN          MASSACHUSETTS 


may  have  a  maximum  capacity  of' 1(10  mint'  and  provision 
for  plu^  in  vacuum  condenser*  ior  the  higher  ranges. 

Since  it  is  not  desirable  to  permit  small  changes  in  load 
capacity  during  the  heating  cycle  to  drastically  affect  the 
voltage  applied  to  the  electrodes,  it  is  apparent  that  separate 
tuning  of  the  load  circuit  is  not  practical.  This  statement 
does  not  intend  to  deny,  that  separately  tuned  circuits  have 
been  used  with  some  success  for  plastics  welding.  However, 
the  adjustment  of  the  system  becomes  rather  tricky  and  is 
not  likely  to  be  mastered  by  the  average  production  foreman. 
When  very  high  frequencies  are  employed  (60  me  and 
above)  as  in  electronic  sewing  machines,  separately  tuned 
load  circuits  have  to  be  used,  because  of  the  difficulty  of  put- 
ting the  load  directly  into  the  tank  circuit. 

K\  en  at  frequencies  of  25  to  30  me  the  wide  range  of  pos- 
sible tank  capacities  necessitates  careful  design  of  the  os- 
cillator  circuit.  The  frequency  is  subject  to  considerable 
variation,  but  this  cannot  be  prevented.  The  larger  C't  is 
made,  the  smaller  the  ratio  between  maximum  and  mini- 
mum tank  capacity  becomes.  Even  at  frequencies  of  25  to 
39  me  the  tank  capacity  cannot  be  too  large,  as  the  tank 
current  becomes  excessive  and  the  efficiency  falls  off.  Conse- 
quently, it  becomes  impossible  to  fully  meet  the  conditions 
obtaining  in  an  ideal  setup.  In  practice,  a  compromise  must 
lie  made  between  maximum  load  capacity  designed  for,  and 
the  frequency  desired.  It  has  been  the  writer's  experience 
that  at  a  frequency  of  30  me  the  largest  total  tank  capacity 
that  can  be  permitted  with  reasonable  efficiency  is  about  100 
nimf  (for  a  plate  voltage  of  about  2750).  At  a  frequency 
of  20  me  this  maximum  tank  capacity  is  about  200  mint'. 
(These  values  include  interelectrode  capacities  and  stray 
capacities.) 

Valuable  Design  Factors 

Stability  of  operation  and  freedom  from  parasitic  oscil- 
lations over  the  relatively  wide  range  of  frequencies  and 
tank  capacities  encountered  is  another  problem.  The  follow- 
ing design  factors  have  been  found  to  be  of  special  value : 

1.  The  variable  portion  of  the  tank  capacity  should  be 
across  the  entire  tank  inductance.   This  is  the  single,  most 
important  factor  in  the  prevention  of  parasitic*.. 

2.  The  use  of  a  separate  coil  for  grid  excitation  makes 
the  degree  of  excitation  a  function  of  the  tank  current, 
which  of  course,  is  subject  to  wide  variation.   The  voltage 
across  the  tank  circuit  is  not  affected  by  changes  in  fre- 
quency and  tank  capacity.   Consequently  the  grid  excitation 
voltage  should  !>e  made  a  fixed  fraction  of  the  total  tank 
voltage. 

3.  The  tank  capacity  should  be  lumped  as  far  as  |Ni**ihle. 
The  stray  capacities  in  the  circuit  should  be  held  to  a  mini- 
mum. 

4.  The  circuit  should  be  arranged  in  such  fashion  as  to 
IK-rmit  grounding  of  one  of  the  electrodes. 

5.  Parasitic   suppressors  do  more  harm  than   good   and 
should  be  avoided. 

Operating  Frequencies 

The  choice  of  the  proper  range  of  operating  frequencies  is 
determined  by  various  considerations.  There  is  no  one 
frequency  which  is  l>e*t  for  all  jobs.  A  suitable  compromise 
depending  on  the  general  pur|H>*c  of  the  equipment  must 
be  reached.  The  following  factors  warrant  consideration: 

1.  The  lightest  gauge  which  the  equipment  shall  l>e  able  to 
handle.  As  has  Ix-en  shown,  at  constant  frequency  about 
the  same  111111111111111  voltage  is  nccc*sary  for  a  wide  range  of 
film  thickness.  However,  the  amount  of  voltage  thai  can 
safely  l>e  applied  to  the  plastics  decreases  for  the  lighter 
gauges  of  film.  Increasing  the  frequency  permits  a  reduction 
of  the  minimum  vultage.  i  1'ouei  absorlicd  by  load  is  pro- 
jM>rtional  to  frequency  and  voltage.)  The  welding  of 
.1X14"  I'inylilf  \\ilh  a  reasonable  factor  requites  .1 

frequency  of  at  least  .VI  me.  l-'iltn  of  .'HIS  gauge  IK'S  can  !><• 


M 


l>i:<  KMHKR   1946 


welded  with  about  the  same  margin  of  safety  by  use  of  a  fre- 
quency of  18  me. 

2.  The  maximum  length  of  seal  that  is  to  be  produced  at 
one  time  limits  the  maximum  frequency  that  may  be  used. 
The  length  of  the  electrodes  should  not  be  greater  than  1/10 
the  wave  length  of  the  high  frequency  in  the  electrodes.  The 
reduction  of  the  wave-length  in  the  electrodes  is  proportion- 
al to  the  square  root  of  the  dielectric  constant  of  the  medium 
surrounding  the  electrodes.   At  30  me  32"  is  approximately 
the  maximum  length  of  seal  that  can  be  welded  at  one  time 
without  special  measures  to  equalize  the  voltage  along  the 
electrodes. 

3.  The  maximum  tank  capacity  that  can  be  handled  de- 
creases with  increasing  frequency.    The  physical  layout  of 
the  welding  system,  especially  the  maximum  length  of  leads 
to  the  electrodes,  limit  the  maximum  frequency  that  can  be 
used. 

4.  In   applications  where  the  duration'  of  welding  time 
must  be  reduced  to  a  small  fraction  of  one  second  (for  ex- 
ample, electronic  sewing  machines)  a  power  input  consid- 
erably above  the  minimum  values  must  be  used.  This  neces- 
sitates the  use  of  a  higher  frequency,  so  that  the  voltage  ap- 
plied need  not  be  excessive. 

Well  Filtered  Power  Supply 

In  all  equipment  designed  for  electronic  welding  of  plas- 
tics, it  is  essential  to  utilize  a  well  filtered  power  supply. 
The  power  input  to  the  load  depends  on  the  rms  voltage. 
Arc-through  is  determined  by  the  peak  voltage.  Proper  fil- 
tering will,  therefore,  permit  the  use  of  a  lower  frequency 
with  the  same  factor  of  safety,  or  the  use  of  the  same  fre- 
quency with  a  higher  margin  of  safety,  than  could  be  ob- 
tained with  an  unfiltered  power  supply.  END 


Plastics  in  Shoes 

(Continued  from  page  24) 


At  present  there  is  a  severe  shortage  of  leather  both  in  the 
U.  S.  and  in  all  foreign  countries.  In  many  foreign  coun- 
tries such  shoe  materials  as  wood,  fabrics,  seaweed,  fish- 
skins,  paper  and  feathers  are  being  used.  These  countries 
are  desperate  for  U.  S.  leather,  but  we  cannot  even  supply 
our  own  domestic  market. 

In  the  past  we  have  depended  largely  upon  imports  of 
rawstock  to  make  leather.  Now  most  of  these  former 
sources  of  supplies  have  drastically  reduced  their  exports 
of  rawstock  to  us.  For  example,  the  bulk  of  our  goatskins 
for  kid  shoes  was  imported  from  52  foreign  countries.  Due 
to  chaotic  changes  in  many  of  these  countries,  a  good  share 
of  these  imports  will  be  sharply  reduced  temporarily  or 
permanently.  In  1941  our  goatskin  leather  production  was 
over  45,000,000  skins.  In  the  year  1945  it  fell  below  30,- 
000,000. 

Scarcity  of  All  Leathers 

The  story  of  most  other  leathers  is  similar.  Foreign 
livestock  populations,  sorely  depleted  by  the  war,  will  re- 
quire five  to  ten  years  before  returning  to  normal  count. 
Some  countries  now  tan  their  own  rawstock,  thus  cutting 
deep  into  U.  S.  leather  production.  Australia  and  South 
America,  two  formerly  large  rawstock  exporters,  are  ex- 
amples. Moreover,  heavy  domestic  demands  for  leather  in 
these  countries  will  keep  much  of  the  finished  leather  supply 
there  instead  of  exporting  it  to  the  U.  S.,  or  some  will  be 


Expressly  designed  for 
granulating  the  various 
types  of  plastic  materials 

Advanced  design  features  enable 
Cumberland  machines  to  perform  at 
maximum  efficiency  the  special  cut- 
ting required  by  plastics  materials. 
Machines  are  made  in  two  styles: 
smaller  machines,  No.  0,  No.  l/z  and 
No.  1  Vz  as  at  right  (No.  Vz  illustrated). 
Style  of  large  machines  as  at  left 
with  retractable  knife 
block  for  maximum 
accessibility  (18"  Ma- 
chine illustrated). 

Request  illustrated 
CATALOG  NO.  200 

CUMBERLAND  ENGINEERING  CO 

Dept.  B— Box  216,  Providence,  R.  I. 


DECEMBER  1946 


PLASTICS 


93 


ELECTRONIC 
HEATSEALING 


Complete  line  of  equipment 
500  watts  to  5  k.w.  output 

Presses  and  Electrodes  de- 
signed to  your  requirements 

Quick  Delivery 
Rugged,  Guaranteed  Equipment 


PLASTIC  WELDING  CORP. 

407  Broomc  St.,  New  York  13,  N.  Y.— CA-6-1 227 


IF  YOU  WANT  OUTLETS 
CONTACT  US 

Anything    pertaining    to    Smokers    Articles 
or   General    Merchandising    and    Novelties 

*  *     * 

We  Contact  Jobbers  and  Chain  Store  and 
Department  Stores  from  Coast  to  Coast! 

(,Wm  trill  Cmrry  Our  »itn  Account  t  (f  JV«r*aMry) 

*  *       * 

M.  B.  SIEGEL 

ASSOCIATES 

FACTORY  UPtlSENTATIVEI  AND  DISTRIBUTORS 
63  E.  ADAMS  ST.  CHICAGO  3.  ILL 


DIRECT  TO 
PRINCIPALS. 

WE  ACT  IN 
OUR  OWN 
BEHALF  AND 
IN  THE 
STRICTEST 
CONFIDENCE 


CAS 


IN     LARGE    SUMS    AVAILABLE 
FOR    QUICK 

PURCHASE 

(OF  ASSETS  OR   CAPITAL) 
•  Industrial  Plant* 
.  Manufacturing  Divs. 

OR  UNITS 
Addrm: 
lot  1241.  147  W.  4]  S».,  N.  Y.  II.  N.  Y. 


sold  to  countries  other  than  the  U.  S.  whose  leather  shortage 
is  critical  and  whose  desperate  bids  are  sky  high. 

This  situation  is  expected  to  grow  even  more  intense.  In 
the  face  of  this  shortage  there  is  an  unprecedented  de- 
mand for  shoes.  If  suitable  materials  were  available,  the 
shoe  industry  could  perhaps  double  its  sales  today. 

There  is  a  limit  to  the  U.  S.  and  world's  leather  supply 
even  in  normal  times.  Actually,  there  has  never  been  enough 
leather,  and  this  shortage  has  become  more  intensified  over 
the  past  two  decades.  Thus,  any  new  shoe  material  would 
not,  in  the  real  sense  of  the  word,  compete  with  leather. 
There  is  plenty  of  room — actually  a  real  need — for  plastics 
in  the  shoe  field,  provided  they  meet  the  special  footwear 
requirements. 

Study  and  Research  Required 

This  is  an  opportunity  which  contains  a  possible  pitfall 
for  over-zealous  plastics  manufacturers.  They  are  gravely 
mistaken  if  they  think  they  can  throw  any  kind  of  plastics 
into  the  shoe  ring.  Despite  his  intense  need  for  materials, 
the  shoe  man  cannot  and  will  not  jeopardize  the  reputation 
of  his  firm  and  product  with  materials  which  fail  to  stand 
the  required  tests.  Moreover,  it  is  foolhardy  for  plastics 
men  to  injure  the  reputation  and  future  of  plastics  in  this 
field  by  making  and  selling  inferior  or  mediocre  plastics 
materials  for  shoes. 

The  logical  step,  in  this  writer's  opinion,  would  be  for 
the  plastics  manufacturers  to  organize  a  committee  to  study 
the  shoe  market  and  its  special  needs  and  requirements  :  then 
to  conduct  research  to  produce  the  types  of  plastics  for 
footwear  in  every  respect.  Such  an  approach  would  pay  off 
quickly  and  profitably  and  would  help  establish  a  vast  and 
permanent  new  market.  END 


Lamina  tin  ff  with  Melamine  Resins 

(Continued  from  page  49) 


of  panels  through  various  sales  district--  in  standard  easel 
frames.  This  type  of  display  is  of  particular  interest  to 
national  sales  organizations  having  a  large  number  of  prod- 
ucts merchandised  through  retail  outlets. 

The  melamine  laminates  possess  hard,  den-c  surfaces 
which  are  unusually  resistant  to  scratching  and  wearing. 
Applied  to  restaurant  counters  and  table  tops,  they  have 
been  exposed  to  service  wear  so  severe,  even  plate  glass  has 
been  badly  scratched.  To  aid  in  preserving  the  decorative 
or  printed  surfaces  of  the  laminate  and  to  increase  abrasion 
resistance  it  is  necessary  to  apply  an  overlay  sheet.  Although 
the  overlay  sheet  causes  a  slight  loss  of  definition  of  the 
printed  pattern  it  creates  an  appearance  of  depth  which  adds 
to  the  richness  of  the  finished  laminate. 

In  order  to  determine  the  effectiveness  of  overlay  sheet-. 
the  1  Mastics  Division  lalwratory  of  Fabricon  Products,  Inc., 
initiated  a  testing  program.  An  instrument  for  testing 
abrasion  by  revolving  a  sample  under  an  abrasive  wheel, 
while  automatically  counting  the  number  of  revolutions, 
was  employed  and  a  series  of  tests  conducted  on  unsui  • 
and  overlay  decorative  panels.  The  end  point  of  the  te-t  \\.i- 
arbitrarily  decided  to  be  that  point  at  which  the  pattern 
was  completely  abraded  or  obliterated.  Results  of  tbi--  te-t 
are  shown  in  the  following  table: 

No.  of  Revolution!  Required 

to  Obliterate  Pattern 
.  9.400 

.  .  .   81.609 

.131.121 


De»criplion  of  Te»»  Panel 

Tan  linen  deiign.  no  overlay  .. 
Tan  linen  design.  3  mil  overlay 
Tan  linen  deiign.  7  mil  overlay 


The  test  clearly  shows  that  the  abrasion  resistance  < 
curative  panels  i-  increased  by  the  u^e  of  an  overlay 


•M 


DKCKMHKR  1946 


and  that  this  increase  in  abrasion  resistance  is  proportional 
to  the  thickness  of  the  overlay  sheet  employed.  Therefore, 
the  use  of  an  overlay  sheet  is  necessary  if  a  high  quality 
abrasion  resistant  panel  is  to  be  required.  In  certain  types  of 
wall  panels,  and  in  applications  where  a  solid  color,  high 
resin  content  surface  sheet  is  used  for  the  top  layers  of  the 
laminate,  the  use  of  an  overlay  sheet  may  be  dispensed  with. 
In  addition  to  the  above  techniques  for  the  handling  of 
melamine  resin  treated  materials,  there  are  two  other  tech- 
niques which  merit  consideration.  The  first  of  these,  is  the 
molded  laminate  type  of  product,  where  the  final  laminated 
product  instead  of  being  a  flat  sheet  or  panel  is  molded  in 
curvature,  either  simple  or  compound.  The  same  funda- 
mentals are  applicable  in  production  of  molded  laminate  as 
in  flat  sheet  except  that  the  layup  or  material  assembly*  is 
usually  die-cut  to  pattern  to  produce  corners,  edges  or  de- 
pressions in  the  final  product.  Because  melamine  resjh 
treated  materials  tend  to  be  brittle  it  may  also  be  necessary, 
in  certain  instances,  to  plasticize  the  resin  treated  materials, 
either  by  the  use  of  steam  or  high  humidity,  or  the  use  of 
certain  chemicals  in  the  resin  varnish.  Considerable  de- 
velopment work  is  being  done  on  the  latter  by  several  or- 
ganizations and  more  efficient  plasticizers  will  probably  be 
available  in  the  not  too  distant  future. 

Molded  laminated  products  are  being  planned  and  are  in 
experimental  production  for  radio  cabinets  where  the  color 
effects,  superior  strength  values  and  ease  of  assembly  can  be 
employed  to  advantage.  Other  similar  applications  are  in- 
strument cases,  business  machine  covers,  food  trays,  etc.  The 
latter  product  has  been  found  superior  to  porcelain  enamel 
trays  because  they  are  lighter  in  weight,  do  not  chip  on  im- 
pact as  readily  as  enamel  trays,  and  because  the  use  of  color 
makes  the  display  of  food  appear  more  appetizing. 

The  other  technique  is  that  of  post-forming  in  a  manner 
similar  to  that  employed  in  the  post-forming  of  phenolic 
cloth  base  materials.  While  the  lattitude  is  not  yet  avail- 
able in  melamine  materials,  modifications  of  the  post-form- 
ing process  are  now  in  production  on  a  limited  scale.  One 
method  employed  is  the  partial  curing  of  the  laminate  in 
flat  sheet  form,  post-forming  and  then  final  curing  in  the 
post-formed'  shape. 

Although  a  rather  wide  range  of  temperatures  is  em- 
ployed in  curing  melamine  materials,  the  range  of  285°  F 
to  305°  F  is  generally  recommended.  The  time  required  at 
the  above  temperatures  is  directly  dependent  on  the  thick- 
ness to  be  laminated.  Overcure  of  melamine  will  not  result 
in  thermal  decomposition  of  the  resin.  Optimum  properties 
and  minimum  warpage  results  when  the  laminate  is  cooled 
under  pressure.  While  laminating  pressures  as  low  as  250 
psi  are  being  employed,  optimum  physical  properties,  gloss 
and  abrasion  resistance  and  minimum  warpage  are  ob- 
tained in  the  pressure  range  of  800  to  1200  psi.  END 


DON'T  MISS  JANUARY  plastics 

This  issue  will  introduce  three  new  regular  monthly 
features: 

1.  A  listing  of  stock  plastics  products,  and  their 
manufacturers.   Covered  in  this  first  series  are 
advertising  novelties  and  premiums,  and  items 
used  in  the  office  and  school. 

2.  A  descriptive  listing  of  kitchenware  and  uten- 
sils, and  their  sources  of  supply. 

3.  A  Buyers'  Needs  column  devoted  to  inquiries 
for  sources  of  finished  and  semi-finished  prod- 
ucts. 


of  REED-PRENTICE 

Plastic  Injection  Molding  Machines 

This  "spic  and  span"  plant  of  Plastic  Engineering,  Inc.,  in  Cleveland 
gives  a  true  impression  of  a  modern,  well-equipped  organization. 

It  is  only  natural  that  Reed-Prentice  injection  molding  machines  have 
been  selected  to  meet  their  rigid  requirements.  A  wide  range  is  offered  for 
your  selection  by  the  complete  line  of  Reed-Prentice  models  —  available  in 
4,  6,  8,  12,  16  and  22  Oz.  capacities.  Write  for  mold  and  machine  information 
to  Dept.  U. 

THE  WORLD'S   LARGEST   M»NUF«CTURERS   OF   INJECTION   MOLDING   MUCHIKES 


CLEAR,  BRILLIANT   LUSTER  FOR   ACRYLICS 

with 


GAMCO "  BUFFING  COMPOUND 


"GAMCO"  grinds  as  it  polishes,  often  eliminates  the 
need  for  any  sanding  between  sawing  and  polishing. 
Thus  a  safe,  fast  means  is  provided  for  giving  thermo- 
plastic synthetic  resins  a  truly  brilliant  luster. 


"GAMCO" 

features 


Will  not 'burn". 

Designed   especially   for   buffing 

acrylics. 

Lowers  cost  of  buffing. 

Contains  no   jeweler's  rouge  or 

grease. 

Melts   into   the   folds   of   the   buffer 

and  feeds  like  a  fountain  pen. 

Cannot  chemically  harm  plastic. 

Your  inquiries  will  receive  prompt  attention. 


Other  GREAT  AMERICAN  products  include  AQUA 
PLASTIC  DYE,  a  permanent  dye  in  water  solution; 
ANNEALING  COMPOUND,  which  creates  a  bond 
stronger  than  the  plastic  itself;  LAMINATING  COLORS, 
tortoise  shell  effect,  a  cement  with  color  —  no  air 
bubbles,  no  streaks.  Also,  a  complete  line  of  cold  dip  dyes. 

N.w    Yo.k    R«pr*»*nlotiv*  :     Plalticf 
Dy.  I  Supply  Co..  Ocvafl  Got*.  N.  J. 

Chicago  R.pl.l.nlal.v.     A.m.  Plolticl 

Evontton.  Ill' 

M.J.ICO    R.pr.l.ntativ.  :    Art.l   Profit. 

cot.  Alp.»  S,  Villa  Obrogon.  D.  F. 

Moxico. 

CUTS    BUFFING    TIME    IN    HALF— SAFELY 


DECEMBER  1946 


FLASTiCS 


95 


Precision-mode   fo  within   .001"  from    finest  steel. 
Durable   edges  that  cut  cleanly   and   easily. 
Uniform  highest  quality.   Will  fit  accurately. 


CLUB  RAZOR  &  BLADE  MFG.  CO.  •  34  GREEN  ST.  •  NEWARK  2,  N.  J. 


PLASTIC  EXTRUDERS  WANTED 

Sizes  2l/2  inch  diameter  screw  and 
larger,  with  either  cross-head  or  straight- 
head  accessories. 

Write  BOX  1 1 5,  c/o  PLASTICS 
185  N.  Wabash  Ave.,  Chicago  1,  Illinois 


"We  have  four  mills  available  for  hot  mixing  of 
your  plastic  compounds  to  specifications.  We  have 
facilities  for  returning  your  material  to  you  in  either 
strips,  sheets  or  granulated.  We  are  experienced  in 
mixing  ot  plastics  for  extrusion,  injection  molding 
and  paint  compounds.  Electronic  Rubber  Company, 
«»  Suriny-id.-  \\i-iim-,  StAiiiford,  Conn." 


MIALL  MOLDING  CORP. 

Injection  and  Compression   Molders 

Toys — Novelties 

Ornamental  Plastics 

and   Metal  Specialties 

Complete  Tool  Room  Facilities 

267-271   Wyckoff  St.          Brooklyn.  N.  Y. 


MAin  5-1829 


ROUTER  BITS— FORM  CUTTERS  and 
MACHINES  for  HIGH  SPEED  CON- 
TOUR and  STRAIGHT  CUTTING  PLASTICS 

-Vrnrf  lot   Cfltlog    No.   41 

EKSTROM,  CARLSON  &  CO. 

Ml*   Railroad   AT..  MOCKFORD.  ILL. 


TWO  OVI  N>  I  <n;  s\l.i; 

Klectrically  heated  8  feet  x  9  feet  x  8  feet.  Batch 
type  with  racks.  Foxboro  controls  and  recorder. 
Up  to  650  degree*  F.  Ready  for  asnembly. 

KOI'MIKV  LKAKIMi  CORPORATION 

i. H  i  hit. .1.1  sire.-t.  v-wnik.  \i-wjrrnrjr 


VIRGIN  ACETATE  MOLDING  POWDER 

STAPLE  SHADES 
FOR  EARLY  DELIVERY 


IRA   HARMON 


41*  Fifth  Avenue 


New  York.  New  York 


Close  temperature  control  oi  injection  molds  is  prom- 
ised through  use  of  new.  compactly  constructed  unit 


Mold  Temperature 
Control 


MERIDIAN  PLASTICS,  Inc.,  a  recently  formed  or- 
ganization, has  two  announcements  of  interest.  Fir-t, 
the  availability  of  a  highly  experienced  personnel  and  mod- 
ern equipment  for  injection  molding,  low  pressure  forming 
and  low  pressure  laminating  of  plastics.  Secondly,  the  de- 
velopment of  a  Temperature  Circulator  designed  primarily 
for  close  temperature  control  of  injection  molds. 

J.  E.  Wolfe  and  D.  L.  Davenport,  who  are  president  and 
vice-president,  respectively,  of  Meridian  Plastics,  claim  that 
their  new  unit  will  be  of  immense  value  to  molder-. 

The  newer,  more  intricate  moldings  utilizing  a  variety  ot 
specialized  plastics,  and  improved  techniques  emphasize  the 
need  for  a  more  accurate  control  of  critical  mold  tempera- 
tures. The  molder  of  thermoplastics  is  well  aware  of  tin-  im- 
portance of  close  control  of  mold  temperatures. 

If  temperature  variations  are  frequent  or  haphazard,  too 
hot  a  mold  may  cause  the  material  to  overflow,  with  an 
attendant  prolongation  of  the  cooling  time  in  the  mold.  Too 
cold  a  mold  will  result  in  poor  surfaces  or  even  freezing  of 
the  material  with  incomplete  filling  of  the  cavity. 

An  excellent  means  of  preventing  these  undesirable  fac- 
tors is  indicated  by  the  use  of  the  Meridian  Plastics  Co.'s 
('(instant  /  rw/vni/iin-  Circulator.  The  unit,  which  appears 
to  be  ruggedly  constructed,  is  made  up  of  two  tanks,  each 
containing  approximately  5l/2  gallons  of  heating  medium 
(water  or  oil).  They  are  mounted  on  a  welded  steel  frame 
which  is  fitted  on  swivel  steel  casters.  The  unit  is  wired 
for  220  volts  single  phase  type,  but  can  IK-  obtained  in  220 
volts,  three  phase.  Each  tank  is  equipped  with  7y3  kw 
specially  designed  heaters  so  that  the  oil  may  be  used  .it 
higher  temperatures,  and  water  n-ed  at  lower  temperatures. 
It  is  recommended  that  neoprene  hose  IK-  used  to  connect 
unit  and  mold  when  high  temperatures  arc  encountered. 

The  ( ~,>n.<taiH  I \-mfcrature  ( 'initiator  can  service  lx>th 
sides  of  the  die  at  the  same  time  and  hold  each  side  at  dif- 
ferent temperatures.  Its  UM-  i>roini-es  to  provide  a  precise 
method  of  determining  and  establishing  correct  die  tempera- 
tures SO  that  valuable  production  records  can  l>c  kept  for 
future  reference.  It  i-  intere-ting  to  note  that  the  unit 
tt-elf  acts  as  a  heat  exchange!  -inee  the  heating  elements 
have  sufficient  capacity  for  a  high  output  of  beat  when 
ary  to  bring  the  mold  to  temperature,  while  built-in 
beat  Insse-  insure  it-  losing  heat  where  reunited.  END 


1'I.ASTH  * 


DKCKMKKK   1946 


Know  You*  Low  Pressure  Resins 

(Continued  from  page  16) 

inmmnniii iimnin 

determining  factors  such  as  surface  hardness  and  an  inhibit- 
ing effect  on  some  resins  might  exclude  the  possibility,  of 
using  copper  and  brass,  leaving  the  choice  between  aluminum 
and  iron.  Molds  of  glass,  plaster,  and  reinforced  plastics  act 
as  pretty  fair  thermal  insulators. 

In  curing  a  thick  section  the  exothermic  heat  has  a  greater 
thickness  of  plastics  to  penetrate  before  it  reaches  the  mold. 
Thus,  the  thickness  of  the  plastics  becomes  the  factor  limit- 
ing the  rate  of  heat  transfer ;  and  since  heat  transfer  through 
plastics  is  slow,  the  thick  sections  must  be  cured  slowly. 

Reinforcements  in  the  resin  reduce  the  effect  of  the  exo- 
thermic heat  by  introducing  an  inert  material,  which  absorbs 
the  heat  necessary  to  bring  it  up  to  the  temperature  of  the 
resin. 

Low  Pressure  Phenolic  Resins 

Phenolic  resins  have  been  used  for  many  years  in  cast- 
ing and  for  high  pressure  molding  and  laminating.  More 
recently  phenolic  resins  which  mold  at  relatively  low  pres- 
sures (15  psi  and  higher)  have  been  made  available  to  the 
laminators.  These  low  pressure  phenolics  are  basically  the 
same  as  their  high  pressure  predecessors  and  cure  in  about 
the  same  temperature  range.  However,  two  basic  molding 
characteristics  have  been  changed  in  these  tailor  made  resins 
to  enable  the  fabricator  to  get  a  completely  satisfactory 
molded  part  while  using  relatively  low  molding  pressures. 

At  curing  temperature  these  low  pressure  phenolic  resins 
flow  at  a  lower  molding  pressure.  During  cure  they  liberate 
volatile  material  much  the  same  as  the  high  pressure  phenol- 
ics. However,  the  volatile  liberated  by  the  low-pressure 
phenolic  resins  can  be  handled  at  low  pressures  without  pro- 
ducing pin  holes  or  blisters  in  the  molded  plastics. 

Phenolic  resins  pass  through  three  distinct  stages,  A,  B 
and  C,  the  last  of  which  is  the  fully  cured  resin.  In  the  A 
stage  the  resin  is  soluble  in  alcohol  and  will  fuse.  This  is 
the  stage  in  which  the  resin  is  commonly  supplied  by  the 
manufacturer.  The  raw  materials  have  been  reacted  to  a 
carefully  controlled  point,  and  are  usually  dissolved  in  a 
water-alcohol  solvent. 

In  the  B  stage  the  resin  has  been  reacted  further.  It  is 
still  fusible,  but  its  solubility  in  alcohol  has  been  reduced 
to  a  low  point.  These  resins  are  dry  and  non-tacky. 

In  the  molding  cycle  the  resin  is  converted  from  the  B  to 
the  C  stage  by  further  reacting  the  resin.  In  the  C  stage 
the  resin  is  insoluble  and  infusible. 

Low  pressure  phenolic  resins  are  usually  available  as  60- 
70%  solutions  of  A  stage  resin.  Some  low  pressure  phenolics 
are  supplied  as  B  stage  powders  to  be  dusted  on  mat  types 
of  reinforcement  and  molded. 

Before  an  A  stage  resin  can  be  molded  satisfactorily,  it 
must  be  advanced  to  the  B  stage  as  a  separate,  preliminary 
operation.  This  is  done  by  applying  it  to  the  reinforcement 
and  advancing  the  cure  by  the  application  of  heat.  The 
solubility  of  the  A  stage  resin  and  the  ability  to  further 
dilute  it  offers  a  convenient  method  of  controlling  the  amount 
of  resin  picked  up  by  the  reinforcement  and  the  degrees  of 
impregnation.  The  application  of  an  A  stage  resin  to  a  rein- 
forcement with  the  use  of  heat  to  advance  the  resin  to  a 
B  stage  is  described  as  a  treating  operation.  Generally  it 
is  a  continuous  operation  with  the  reinforcement  passing  ( 1 ) 
through  a  dip  tank  where  it  picks  up  an  excessive  amount 
of  resin,  (2)  through  wiping  rods  or  metering  rolls  where 
the  excess  resin  is  removed,  and  (3)  through  a  hot  air  or 
infra-red  heated  oven,  where  the  resin  is  advanced  to  the 
B  stage. 

The  reaction  rate  of  any  specific  phenolic  resin  is  con- 


Q.  When  is  a  plastic  problem  not  a  problem? 

A.  When  the  plastic  moulder 
knows  the  right  plastic  to  use 
for  the  job  at  hand  and  has  the 
"know-how"  to  put  maximum 
beauty,  durability  and  sales 
appeal  into  the  finished  product. 

Magnetic  Plastics  are  that  kind 
of  plastic  moulders.  Perhaps 
there's  a  plastic  answer  to  your 
problem.  Just  send  sketch, 
sample  or  specifications  and 
we'll  tell  you  quickly  if  it  can 
be  made  in  moulded  plastics. 


MAGNETIC  PLASTICS  & 


/1900   EUCLID    BUILDING     •     CLEVELAND    15,  OHIO/ 


MANUFACTURERS    OF 


ANY     COLOR  ANY    FLOW 


DECEMBER  1946 


PLASTICS 


97 


ATTENTION -RECORD  MANUFACTURERS! 

New  INDUSCO  75  Ton  and  100  Ton  Semi-Automatic  Phonograph  Record 
Pruning  Units,  Comprising  Presses.  Pumps,  Motors,  Hydraulic,  Sttam 
and  Water  Valves,  Automatic  Timart  ana  All  Accessories.  Tha  75  Ton 
Units  lor  10-  and  IT  Shellac  and  IIT  Vinylite  Records.— the  100  Ton 
Units  for  12"  Vinylita  Racords.  Prompt  Deliveries. 

Naw  INDUSCO  157  Ton  and  400  Ton  Mobbing  Prauas,  12'  Dayliorrt. 
Hardanad  Staal  Anvils,  Each  Complete  with  Eithar  Hand  or  Power 
Drlvan  Pump  with  Ntcasury  Piping  and  Accessories 

Naw  INDUSCO  n  Ton  100  Ton,  ITS  Ton  and  22S 
Ton  Molding  Praisas,  Platan  Sizas  from  12"  •  12" 
up  to  30"  i  24".  Daylight  Openings  to  Suit. 

Various  Silas  and  Capacities  of   Usad,  Guaran- 
teed, and   Naw   Presses,   Pumps,   Accumulators. 
Prompt  Deliveries.     Full  Details  on   Request. 

Write.   Wire.   Pnone 

INDUSTRIAL   EQUIPMENT  COMPANY 

173  (rood   Street  Newark  2,  New   Jersey 


We  will  engineer  and  produce  your 
product  in  Plastic  at  a  minimum  of  cost. 

CUSTOM  INJECTION  MOLDING 
QUOTATIONS   UPON   REQUEST 

MIDLAND  PLASTIC  MOLDING  CO. 
1511  E.  Grove  Street  Midland.  Michigan 


WAITED 

TOOL   COMPANIES 

that  have  made  and  can  make  Injection  molds  for  doll 
.heads  and  doll  parts.  Prominent  large  doll  manufac- 
turer plan*  to  enter  field  of  plastic  molded  dolls,  and 
seeks  a  reliable  tool  company  to  do  all  tool  work. 

II. .»    I'M  «27.   l  i:;    \\     42  St. 


PATENTS  and  TRADE  MARKS 

'   ninl  i>n>flt  by  your  Idean.     Full  Information  on 
request      Prompt  expert  service.     32  years'  experience. 

LESTER  L  SARGENT 

Retrlsterrd  Patent  Lawyer 

Post  Office  Box  11SC 
111.1  K.  St..  N.  \V.  \\  ...i.Miui"".   D.  C. 


WANTED  TO  BUY: 

Phenolic    impregnated   scrap, 
rags  or  remnants. 

RAYON    PROCESSING    CO.,    OF    R.    I.,    INC. 
86  Tremont  St.,  Central  Falls,  R.  I. 


"KRIEGR-O-DIP" 

HOT  AND  COLO 
Dyei  lor  All  Typei  of  Plastic* 


Sy 

KRIEGER   COLOR   *   CHEMICAL  CO. 

Member  ol  Ihe  S.P.I. 

Tel.   Hlll.id.   7111  (5)1   ftanla   Monica  Blvd. 

HOLLYWOOD    M.    CALIF. 


AUSTIN  TOOL  &  MFG.  CO. 

1859  L  63rd  STREET       •:•       CLEVELAND  3.  OHIO 
EXpre»   1000 

DU40NUS  PLASTIC  MOLDS  •uiioas 

Q»OTsHoiH  W.tfcii,  41 


trolled  by  its  pH.  Usually  there  is  some  point  on  the  pH 
scale  where  the  phenolic  resin  cures  very  slowly.  A>  the 
pH  is  changed  in  either  way  from  this  neutral  point,  the 
resin  becomes  more  reactive  and  consequently  cures  more 
rapidly.  The  cure  rate  of  some  laminating  phenolic  resins 
cap  be  accelerated  by  adding  caustic  soda  to  the  A  static 
resins.  However,  a  few  of  the  laminating  phenolic  resins 
should  not  be  modified.  The  resin  manufacturer  can  supply 
definite  recommendations  on  the  advisability  of  modifying 
his  resins  to  accelerate  the  curing  rate. 

A  stage  phenolic  resins  are  best  stored  in  closed  cans  at 
70°F.  or  lower.  Phenolic  treated  cloth  (B  stage  resin)  can 
be  stored  for  a  month  or  two  at  storage  temperatures  up  to 
70°F.  To  maintain  the  proper  volatile  content  in  the  resin, 
the  treated  cloth  is  stored  in  specially  treated  vapor  re- 
sistant paper,  and  where  possible,  in  a  humidity  controlled 
room. 

The  curing  of  a  phenolic  resin  is  the  step  which  convt-n- 
it  from  the  B  to  the  C  stage.  In  the  B  stage  the  resin  is  dry 
to  the  touch  and  easily  handled.  Heat  reacts  the  resin  caus- 
ing it  to  cure.  Without  pressure,  the  volatiles  in  "boiling" 
out  of  the  phenolic  resin  cause  bubbling  which  in  turn  pro- 
duces pin  holes  and  blisters  in  the  finished  piece.  With 
pressure,  the  resin  flows  into  a  solid  mass  and  the  volatile 
is  kept  in  solution  in  the  resin  as  it  cures,  thus  giving  a 
satisfactory  plastics  part.  The  term  B  stage  resin  is  used 
to  define  a  rather  wide  range  of  volatile  contents  and  flow 
characteristics.  As  a  resin  is  further  advanced  into  the  B 
stage  in  the  treating  operation,  the  volatile  matter  and  the 
resin's  ability  to  flow  under  beat  and  pressure  are  reduced. 
The  ability  of  a  specific  resin  to  flow  is  increased  as  the 
volatile  material  is  increased.  However,  only  a  limited 
amount  of  volatile  can  be  tolerated  at  low  pressures  before 
pin  holes  and  blisters  appear  in  the  molded  part.  The  low 
pressure  resins  are  designed  specifically  to  supply  good  flow 
characteristics  at  low  volatile  contents. 

Tests  Determine  Molding  Qualities 

Two  tests  can  be  made  on  the  B  stage  resin  to  determine 
its  molding  characteristics.  In  the  first,  the  volatile  content 
can  be  determined  by  heating  in  a  hot  air  oven  with  mod- 
erate air  circulation.  The  B  stage  resin  can  be  heated  for 
10  min  at  320°F.  The  volatile,  recorded  as  per  cent  volatile 
matter,  is  calculated  as  follows : 

%  v  M. = initiai  "^^ Weight  x  100 

Initial  Weight 

For  glass-phenolic  combinations  molded  at  low  pressures, 
tlif  Y.M.  will  vary  from  3  to  5%.  For  cellulose-phenolic 
combinations  molded  at  low  pressure  the  V.M.  will  usually 
be  between  4  and  7%. 

In  the  second  test  for  flow  characteristics,  the  treated 
cloth  is  molded  between  flat  plate*.  The  amount  of  resin 
flashed  beyond  the  edge  of  the  cloth  is  measured  and  re- 
corded. This  test  is  particularly  valuable  when  the  treated 
cloth  is  molded  at  the  same  temperature  and  pressure  as 
that  which  will  be  used  in  the  final  molding  operation. 

There  are  no  sharp  lines  defining  the  range  in  which  these 
low  pressure  phenol  ics  can  be  molded.  Some  pressure  is 
required,  and  as  the  molding  pressure  is  increased  to  50  psi 
the  physical  properties  of  the  molded  plastics  parts  show 
marked  improvement.  As  the  molding  pressure  is  increased 
i  •  UK)  psi  the  physical  properties  of  the  molded  parts  arr 
improved,  but  not  as  rapidly.  The  molding  pressures  may 
be  extended  well  in  excess  of  100  psi  with  slight  inn 
ment.  However,  other  considerations,  particularly  molds 
and  molding  equipment  tend  to  keep  molding  pressures  be- 
tween 40  and  1"0  psi.  Curing  temperatures  are  in  the  same 
range  as  their  high  pressure  predecessors,  generally  275° F. 
to  325" F. 


98 


Fl.lSTH'X 


DECKMHKR  1946 


ENCYCLOPEDIA  OF  HYDROCARBON  COMPOUNDS 

Compiled   by  Dr.  Joseph   E.  Faraday 

This  is  the  opening  volume  of  the  first  encyclopedic  type  of 
work  in  English  on  the  compounds  of  carbon.  It  is  an  effort  to 
bring  up  to  date  and  arrange  in  simplified  and  condensed  form 
the  classical  German  works  of  Richter  and  Beilstein,  at  least  so 
far  as  the  hydrocarbons  are  concerned,  and  to  encourage  subse- 
quent compilations  of  the  other  organic  compounds. 

It  has  been  the  aim  of  the  editor  to  present  information,  where 
it  was  available,  on  the  molecular  formula,  expanded  structural 
formula,  the  various  names  by  which  a  compound  is  known,  its 
occurrence,  methods  of  preparation  (with  references  to  the  litera- 
ture), the  form  if  other  than  merely  liquid  or  solid,  the  melting 
point,  boiling  point,  freezing  point,  density,  solubility  in  organic 
solvents  and  other  outstanding  properties. 

As  it  works  out,  the  bulk  of  the  space  is  devoted  to  methods  of 
preparation.  These  are  not  given  in  detail,  but  the  basic  reaction 
is  indicated. 

The  encyclopedia  is  in  loose  leaf  form,  in  a  binder.  Supple- 
ments, to  be  issued  once  a  year,  will  provide  information  on  new 
compounds,  and  new  information  on  known  compounds. 

The  present  volume  covers  the  hydrocarbons  having  one  to 
five  carbon  atoms. — Chemical  Publishing  Co.,  Inc.,  Brooklyn, 

\.  y.,  $15. 


PLASTICS  HANDBOOK  FOR  PRODUCT  ENGINEERS 

Compiled  and  edited  by  John  Sasso 

A  collection  of  engineering  data  gathered  from  material  pre- 
pared by  especially  qualified  authorities  on  their  respective  sub- 
jects, and  is  devised  to  supply  the  reader  with  concise  informa- 
tion on  a  variety  of  phases  of  the  plastics  and  synthethic  rubber 
fields,  to  aid  the  engineer  who  is  considering  use  of  these  ma- 
terials in  new  product  designs. 

The  volume  is  divided  into  three  parts,  the  first  of  which  deals 
with  plastics  materials ;  there  are  five  chapters  in  the  section, 
covering,  respectively,  the  chemistry  of  plastics,  the  various 
plastics  materials  and  their  properties,  processing,  machining  and 
finishing,  and  recent  developments  and  techniques. 

The  second  section  is  concerned  with  design  of  plastics  prod- 
ucts, and  its  three  chapters  are  devoted  to  "Fundamental  Design 
Considerations,"  which  covers  a  number  of  factors  of  the  sub- 
ject, from  selection  of  material  to  design  for  appearance;  "Design 
Details,"  and  "Common  Faults,  Causes,  and  Remedies  in  Molded 
Plastics  Parts." 

Section  three  treats  with  rubberlike  materials  and  their  chem- 
istry and  application ;  seven  chapters  are  included  in  this  section, 
containing  data  on  natural  rubber,  synthetic  rubberlike  mate- 
rials, butyl  rubber,  butadiene-acrylonitrile,  GR-S  synthetic  elas- 
tomers, neoprene,  and  thiokol  polysulfide. — McGraw-Hill  Book 
Co.,  New  York,  N.  Y.,  468  pages,  $6. 


The  January  issue  of  plastics 

will  inaugurate  a  regular  monthly  feature  written  by  an  out- 
standing plastics  authority — Henry  W.  Harding,  president  of 
Chemaco  Corporation. 

This  will  be  an  interpretative,  up-to-the-minute  analysis  and 
commentary  on  events  of  interest — which  occur  not  only  in 
the  plastics  industry,  but  industry  in  general — as  they  affect 
the  plastics  field. 

Don't  miss  this  exciting,  new  presentation  of  current  events! 


FOR 

WEAR-DEFYING 

AUTO 

SEAT  COVERS 


Thanks  to  SARAN.  auto  seat  covers  have 
reached  a  new  high  in  wear-resistance  and  long 
life.  Fabrics  woven  of  SARAN  stand  up 
proudly  under  rough  treatment  .  .  .  are  not 
affected  by  dirt,  grease  and  chemicals  .  .  .  fulfill 
your  highest  expectations  for  beauty,  in  color 
and  texture. 


An  illustrated-  booklet  on  SARAN  BY 
NATIONAL  is  yours  for  the  asking. 
Please  write  on  your  company  letterhead. 


IN  GOLD,  SILVER  OR  COLORS 


DECEMBER  1946 


PLASTICS 


99 


Accurate  Molding  Corporation 

flolhschild  Advertising  Agency  77 

American  Molding  Powder  &  Chem.  Corp. 

H  W.  Fairfax  Advertising  Agency  97 

Ama*  Molded  Plastics 

Sidener  and  Van  Riper,  Inc  12 

Austin  Tool  &  Mlg.  Co.  98 

Bamberger,  A. 

H  W.  rairiax  Advertising  Agency.  Inc  79 

Boonton  Molding  Company 

The  Franklin  Fader  Company  3 

Bnlhart.  Arnold.  Ltd. 

Henri  Le  Motbe  Agency   .  .  .  Fourth  Cover 

C  Thru  Ruler  Company 

Post,  /ohnson  &  Livingston,  /nc. 
Cello-Plastic  Chemical  Co. 

The  McCar  fy  Company 
Celluplastic  Corporation 

M.  C.  Diedrich  Advertising 
Clarendon  Mfg.  Co. 

Lou  Hanqcl  Advertising  Agency 
Club  Razor  6  Blade  Mlg.  Co. 

Raymond  Advertising  Agency 
Continental  Plastics  Corporation 

lira  Duffy  Company. 
Continental  Screw  Company 

Rossi  4  Hirshson 
Cook,  Lawrence  H.,  Inc. 

George  T.  Metcalf  Co. 
Cumberland  Engineering  Co. 

Richard  Thorndize  Precision  Adv. 


Dale  Vent  O-Sole,  Inc. 

Brad-Vern,  Van  Diver  4  Car/yle.  /nc. 
Duall  Molding  Corporation 

Gunn-Mears  Advertising  Agency 

Ekstrom,  Carlson  &  Co. 

Cummings-Brand  4  McPherson 
Electric  Auto-Lite  Company,  The 

Rufhraufr  4  Ryan.  Inc. 
Electronic  Rubber  Company 

Foundry  Leasing  Corporation 
Frank  Paper  Products  Corporation 
Burke  BarfJert  Company 

General  Chemical  Company 

Afaerron  &  Currier.  Inc. 
General  Electric  Company 

Senior.  4  Bowles.  Inc.   . 


84 

.81 
42 
90 
96 
..75 

.67 
65 

.   93 

101 
96 

96 

53 
96 

96 
102 

..   41 
7 


Oering  Products,  Inc. 

M.  C.  Diedrich  Advertising  59 

Girdler  Corporation.  The 

Roche.  Williams  4  CJeary,  Jnc.  5 

Goodrich,  B.  F..  Chemical  Co. 

GriswoJd-EshJeman  Co.,  The  . .  Second  Cover 
Grays  Harbor  Industries,  Inc. 

Frederick  C.  Baker  and  Associates  78 

Great  American  Color  Company 

Bodine  4  Meissner  Advertising  95 


Harmon.  Ira   96 

Hydraulic  Press  Mfg.  Co.,  The 
lay  H.  Maish  Company,  The 3 

Industrial  Equipment  Company 

Louis  F.  Herman  Advertising  Agency  98 

Industrial  Molded  Products  Company 

WesJey  £.  Sharer  4  Associates  47 

Karlstad.  Andrew  C 100 

Kingsley  Gold  Stamping  Machine  Co. 

Continental  Advertising  Service 99 

Kirk,  F.  I.,  Molding  Co. 

Cory  Snow,  Jnc 84 

Krieger  Color  &  Chemical  Company 

Warren  P.  Fehlman  Agency 98 

Kuhn  &  Jacob  Molding  &  Tool  Company 

Eldridqe-Norlhrop.  lac 73 

Kurz-Kasch.  Inc. 

Kircher.  He/ton  4  CoUell 11 

Leach.  H..  Machinery  Co. 
Joseph  Maxheld  Company          .  65 

Mack  Molding  Company 

George  Homer  Martin 51 

Magnetic  Plastics  Company 

Gregory  House  Advertising,  Inc 97 

Meyercord.  Company,  The 

C.  C.  Fogarry  Company  36 

Michiaan  Molded  Plastics,  Inc. 

WaiJace-Lindeman,   /nc 21 

Midland  Plastic  Molding  Company  .  .  98 

Missouri  State  Division  of  Resources  4 
Development 

Potts-Turnbul/  Co 89 

Mosinee  Paper  Mills  Company 

KJdu-Van  Pieterson-Dun/ap  Assoc 25 

National  Lock  Company 
L.  W.  Ramsey  Company 87 


National  Plastic  Products  Company 

The  Joseph  A.  Wi/ner  Company 99 

New  Jersey  Sprayed  Products  Co..  Inc.  74 

Nicholl  Hard  Chrome  Service 84 

Northern  Industrial  Chemical  Company 

The  CaUaway   Associates  92 

Oxley,  John  H.,  Company 

Allied  Advertising  Agency 92 


Pennsylvania  Coal  Products  Company 

Lee  Murray  Advertising 8 

Plaskon  Division,  Ubbey-Owens  Ford  Glass  Co. 
Me /drum  &  Few  smith  35 

Plastic   Masterpieces    ,,  100 

Plastic  Welding  Company  94 

Printloid,  Inc. 

Weiss   Advertising    .88 

Radio  Receptor  Company,  Inc. 

O.  S.  Tyson  &  Company.  Inc.  63 

Rayon  Processing  Co.  of  R.  I.,  Inc. 

Richard  Thorndike  Precision  Advertising  9J.  98 
Reed-Prentice  Corporation 

Howard  Wesson  Company 95 

Rohm  4  Haas  Company 

Newell  Emmett  Company  .  27 

John  Royle  &  Sons B2 

Sargent,  Lester  L 98 

Schwab  &  Frank.  Inc. 

Burke  BartJeft  Company  70 

Schwartz  Chemical  Co. 

Walter  W.  Wiley  Adv.,  Inc 88 

Siegel,  M.  B.,  Associates 

Craig  £.  Dennison  Advertising  Agency  98 

Society  of  Plastic  Engineers 

Howard  D.  Sfeere  Advertising  80 

Stokes.  F.  J.,  Machine  Company 

McLain  Organization,  Inc.  6 

Stricker-Brunhuber  Company 

AJdridge-Preston   Advertising  86 

Tennessee  Eastman  Corporation 
Kenyan  &  Eckhardt,  Inc. 

Van  Dorn  Iron  Works  Company.  The 
UubbeU  Advertising  Agency,  The 31 

Williams  Apparatus  Company.  Inc 86 

Worcester  Moulded  Plastics  Company 

C.  /erry  SpauJding,  /nc Third  Cover 

Wm.  Wriglev  Jr.,  Company 

Ruthrautt  &  Ryan,  Inc 83 


17 


WANTED 

Company  to  extrude  with  vinyl  plastic  our 

wire  .030  diameter  .080  outside  in  quantities 

of  1,000,000  to  10,000,000  feet 

Wire  Box  120,  % 


PUitict 


IK  N.  Webeih  Avenue 


Chicago   I.  Illlnoit 


ANDREW    C.    KARLSTAD 

INDUSTRIAL  DESIGNER 

COMPUTE    PRODUCT   DESIGN   &   ENGINEERING    SERVICE 


4I4»  VENTURA  CANTON  AVE. 
PHONE— STATE  4-S4M 


SHERMAN  OAKS.  CALIF. 
(A  SUIUM  OF  LOS  ANGELES) 


~   W*  ore  irorfUo  eef  rkli  «w>irll  will,    - 

THE    SMALLEST   AD    IN    "PLASTICS" 

l»ri«d  lit  a  lottom  Center  o<  on*  o(  tke  Loi«   Pog»«. 

Write  today  lor  qeneroua  Iree  sample  cakea  ol  "LUCY  PLEX" 
and  "CATY  DAK"  plastic  buHinq  compounds.  Fail  Action,  hlqh 
optical  polish.  Non  burning.  Be  surprised!  Enclose  12c  poilaqe. 

—»    PLASTIC      MASTERPIECES— 
529  Wtst  Mincktsltr  »v»..  Lot  Ang.lti  44.  Cilll 


CLASSIFIED  ADVERTISING 


Foil  S.M.K  :  W.iNnu  Silllman  Hydraulic  preformed  press  with  wplfhlnc 
attachment.  Automatic,  used.  New  250  ton  semi-automatic  hydraullr 
molding  presses.  Immediate  drllrery.  Grant  Engineering  Co.,  1640  Pralrlr 
.\\<-  .  QUMSjl  IP,.  Ill 


HI'TloNS     WP-  .it.-  located   i!.  ..'"I  pl'.ini:  bMtjMsl  "Jili  Hi>-  V'"    V'ri,   11  ,• 
ton  Jobber*  market.     We  have  ample  space  and  can  financially   handlr 
distribution  or  representation.     Box  121,  %  Plastics,  185  N.  Wabash  Are.. 
Chicago  1.  HI. 


(•LAM  •HUM*!  KM  mdlai  Pluti  •  m.i  I;<H  •>.,  r  M,.:.IH,;  »•»«• 
Itsbed  M  years,  rlclntty  Trenton.  N.  J.,  offen  eicellent  future  to  execu- 
tlte-type.  college-trained  engineer  with  10  yean  practical  experience  siient 
preferably  In  rubber  and/or  plastics  Position  enulls  organizing  and  di- 
recting all  plant  serrlce  and  maintenance  facilities  such  as  drafting,  me- 
chanical, electrical  and  power  In  a  plant  normally  employing  604  person- 
I'lesse  write  fully,  giving  experience  and  salary  expected.  Box  122,  r, 
Plastics.  185  N.  Wabash  Are..  Chicago  1.  111.  _ 

FOR  BALK  :  Hydraulic  Press  :  Preco  Hydraulic  Laminating  and  Lib  Prat*. 

equipped  with  8*xl«-  platen,  electrirally  heated,  water  cooled,  brand  ne». 
Including  Moeller  Duplex  Dial  Thermometer*  ;  cost  $88000;  will  sell  for 
irtOO.OO  fob  Buffalo.  Write  Box  123.  %  Plastics.  185  N  Wahash  AIT  . 
Clilc«|ii<  1.  Ill  _ 
_  tITUATIOMi  WAMTtD  _ 

(  MKMICALS—  Haw  materials  Impart  purchasing  —  export  Top  Man  of 
world-known  House,  oter  i  years  In  present  employ.  41  yr»  .  sggresslif 
dependable,  wishes  to  Join  ethical,  aggressive,  financially  strong  organi- 
zation. Box  11*.  ',  I'lastlrs,  1S5  N.  Wabash  Are  ,  Chicago  I,  111. 


U.  S.  SAVINGS  BONDS 

STILL  YOUR  SUREST  WAY  TO 
SAVE   MONEY 

Buy  them!          Keep   them! 


inn 


I)K( -K.MKKK    li 


Statistical  Data 


A  GRAND  total  of  69,436,155  Ib  representing  the  shipments 
and  consumption  of  plastics  and  synthetic  resins  for  August 
1946  was  reported  by  the  Bureau  of  the  Census. 

There  is  a  strong  feeling  in  the  plastics  industry  that  the  peak 
figure  for  August  represents  a  truly  heroic  achievement  by  the 
materials  suppliers.  Output  for  the  balance  of  the  year  is  ex- 
pected to  drop  sharply  because  of  the  cumulative  effect  of  past 
strikes  and  restrictions  and  the  continuance  of  certain  retard- 
ing factors. 

Because  of  changes  in  several  divisions  of  the  Census  report 
accurate  comparisons  with  previous  months  is  not  possible.  How- 
ever, the  increase  for  the  phenolic  and  other  tar  acid  resins  is 
substantial.  The  nitrocellulose  plastics  increased  a  scant  few 
pounds  while  polystyrene  in  dropping,  failed  to  make  the  usual 
substantial  gains  of  the  past  few  months. 

The  statistics  below  represent  the  shipments  and  consumption 
of  plastics  and  synthetic  resins  as  reported  by  78  manufacturing 
companies  and  company  departments.  The  increase  in  the  number 
of  manufacturers  over  that  shown  in  the  previous  release  ( Series 
M19H-76)  is  due  to  the  inclusion  of  statistics  for  one  company 
not  previously  reporting.  (See  footnote  4  below.)  Data  for 
synthetic  resins  for  protective  coatings  are  not  included.  Ship- 
ments, for  the  purpose  of  this  report,  include  data  for  plastics 
and  resins  which  are  manufactured  by  the  reporting  companies 
or  company  divisions  and  shipped  to  outside  users.  Consumption 
refers  to  the  quantities  of  plastics  and  resins  which  are  manu- 
factured and  used  by  the  reporting  companies  or  company  divi- 
sions. Statistics  are  available  beginning  June  1945.  Data  for 
cellulose  plastics  products  only  are  available  for  earlier  periods. 


Plastics  and  Synthetic  Resins  Shipments 
'and  Consumption  (Ib) 


Item 


August 
1946 


July 
1946 


Cellulose  acetate  and  mixed  ester  plastics' 
Sheets 

Continuous  (under  .003  gauge) 601 ,625  770,495 

Continuous  (.003  gauge  and  upward) 519,286  687,416 

All  other  sheets,  rods  and  tubes 388,359  425,370 

Molding  and  extrusion  materials 7,242,206  7,166,800 

Nitrocellulose  plastics' 

Sheets 909,438  921,163 

Rods  and  tubes 629,477  602,614 

Other  cellulose  plastics' 1,118,257  1,451,488 

Phenolic  and  other  tar  acid  resins 

Laminating  (dry  basis) 3,068,525  2,338,486 

Adhesives  (dry  basis) 1,481,024  1,199,637 

Molding  materials' 14,640,213  14,190,536 

All  other  (dry  basis)3 5,949,009  4,977,055 

Urea  and  melamine  resins 

Adhesives  (dry  basis) 44,290,229  3,371,475 

Textile  and  paper  treating  (dry  basis) 1,475,196  1,303,859 

All  other  (dry  basis)  except  molding  material3,5  294,649  263,649 

Polystyrene' 5,725,860  5,746,830 

Vinyl  resins 

Sheeting  and  film1 2,426,090  2,107,886 

Textile  and  paper  coating  resins  (resin  content)  2,909,605  2,134,392 

Molding  and  extrusion  materials  (resin  content)  4,874,830  '5,511,569 

Adhesives  (resin  content)8 

All  other  (resin  content)3 2,733,266  2,972,245 

Miscellaneous  plastics  and  resins 

Molding  materials1,11 4,829,835  6,403,457 

All  other  (dry  basis)3,10 3,329,176  3,695,753 


TOTAL 69,436,155    68,242,175 

'Includes  fillers  plasticizers  and  extenders.  Includes  methyl  and  ethyl  cellulose  and 
related  plastics.  This  information  represents  a  combination  of  molding  and  extrusion 
materials  (statistics  previously  included  with  miscellaneous  molding  materials)  and  sheets 
rods  and  tubes  (statistics  previously  not  published).  Comparable  figures  for  "Other 
cellulose  plastics"  are  as  follows:  June,  1 ,1  37,802;  May,  1,106,419;  April,  1,063,984; 
March,  935,965;  February,  800,827;  January,  848,634.  ^Excludes  data  for  protective 
coating  resins.  4Data  for  one  company  not  previously  reporting  are  included;  however 
this  does  not  appreciably  affect  the  comparability  of  the  statistics  for  previous  months. 
5Urea  and  melamine  molding  materials  included  with  miscellaneous  molding  material}. 
''Dry  basis  including  necessary  coloring  material.  7Revised:  Statistics  for  months  prior  to 
July  1946  will  be  shown  in  a  subsequent  issue.  8Cannot  be  shown  separately  without 
disclosing  operations  of  individual  establishments.  'Includes  data  for  urea  and  melamine, 
acrylic  acid  and  miscellaneous  molding  materials.  Data  for  cellulose  molding  and  extru- 
sion materials  formerly  combined  with  this  item  are  naw  included  in  "Other  cellulose 
plastics."  Therefore  data  for  August  are  not  comparable  with  previous  months.  (See 
footnote  2.)  10lncludes  data  for  petroleum  resisn  acrylic  acid  ester  resins  mixtures  and 
miscellaneous  synthetic  materials. 


DOES  MORE  FOR  FOOT  COMFORT 

THAN  ANYTHING  IN  YEARS 

•  Heavy  Duty  ($1.25) 
is  for  safety  and 
other  work  and  sport 
shoes.  Medium  Duty 
($1.00)  is  for  street 
and  dress  shoes — U.  S. 
Army  and  British 
Government  bought 
millions  •  Woven 
plastic  •  Flows  air 
under  feet  •  Safe- 
guards against  ath- 
lete's foot  and  blis- 
ters •  Helps  prevent 
infection  •  Retards 
fungi  •  Keeps  feet 
dry  •  Rids  shoes  of 
perspiration  •  Reduces  fatigue  •  Guaranteed  •  Free  folder. 

For  additional  informa'ion  see  October  1946  issue  PLASTICS 

MAIL   THIS   COUPON 


DALE  VENT-O-SOLE,  INC. 

45  Halleck  St.,  Newark  4,  N.  J. 

On  your  Money-Back  Satisfaction  Guarantee  here's  (  )  $1.25 
Heavy  Duty  (  )$1.00  Medium  Duty  for  one  pair  of  shoe 
ventilators. 

My  shoe  size  is 

NAME 

ADDRESS 

CITY STATE 


t* 

SPECIFICATIONS 


ing  lines  .  .  .  compound  curves  and  contours  are 
features  of  design  in  a  mass-produced  plastic  product 
which  can  only  be  achieved  through  extraordinary  skill 
plus  infinite  patience  in  following  blueprint  speci- 
fications to  the  letter. 

At  KIRK  MOLDING  you'll  find  specialists  in  trans- 
lating the  original  blueprint  design  into  the  finished 
product.  When  you  specify  KIRK  MOLDING  as  the 
producer  of  your  plastic  product  —  whether  it  be  a 
consumer  item  or  a  vital  part  for  your  production  line  — 
you  can  depend  on  KIRK'S  fidelity  to  measure- 
ment details. 


Consult  KIRK  •"».*?* ,SlfStoBS»l^C^£ 

rtff-irt&s?1^^5  *r 


F.  J.  KIRK  MOLDING  CO. 

CLINTON,        MASSACHUSETTS 


DECEMBER  1946 


PLASTICS 


101 


PROBLEMS 


\n  plastics 


Problems  and  questions  may  b*  submitted 
to  this  department  for  answering  by  the  tech- 
nical editors  or  specialists  in  the  industry. 

We  are  desirous  of  obtaining  a  webbing  material  for  metal 
furniture,  such  as  is  used  outdoors  during  the  summer.  Is  there 
any  plastics  material  made  up  in  this  way  which  is  more  weather- 
resistant  than  canvas?  H.  B.,  New  York,  N.  Y. 

There  are  several  different  types  of  plastics  materials 
produced  for  this  purpose  which  are  far  stronger  than 
canvas  and  more  resistant  to  water.  Strips  of  both 
polyi-inylidene  chloride  and  polyethylene  have  been 
found  satisfactory. 

Plastics-coated  fabrics  have  also  been  used  for  this 
purpose,  especially  polyiinyl  butyral  on  canvas.  This 
gives  the  natural  fiber  of  the  fabric  a  high  abrasion 
resistance,  as  well  as  resistance  to  moisture. 


It  occurs  to  us  that  plastics  would  be  a  logical  material  to  be 
used-  in  the  production  of  doll  bodies.  Can  you  tell  us  whether 
this  is  being  done?  G.  T.,  St.  Augustine,  Fla. 


Although  this  would  seem  to  be  a  natural  application 
for  plastics,  so  far  as  we  know  there  are  no  plastics  doll 
bodies  on  the  market  at  present.  However,  sci>eral  of 
the  large  doll  manufacturers  are  now  working  on  the 
development  of  such  a  body. 

*     *     * 

By  what  method  can  polyethylene  sheeting  be  joined? 

S.  W..  Boston,  Mass. 

This  is  one  of  the  difficult  problems  posed  by  the 
relatively  new  polyethylene  or  polythene.  Although 
this  material  cannot  be  sealed  by  high  frequency  heat- 
ing, due  to  its  low  dielectric  loss,  it  can  be  sealed  by 
ordinary  heat  under  carefully  controlled  conditions, 
and  a  limited  range  of  specific  adhesives. 


We  have  heard  of  a  new  cold  molding  powder  which  is  avail- 
able in  colors.  Can  we  use  this  powder  in  molding  checkers  in 
an  ordinary  rotary  preforming  press?  M.  L.,  Independence,  Ore. 

No.  The  new  cold  molding  powders  require  special 
equipment  which  utilises  pressures  as  high  as  40flOO 

psi. 

*     *    » 

Please  tell  us  what  plastics  material  is  used  in  making  ping- 
pong  balls.  Who  are  the  manufacturers  of  this  material  ? 

D.  C,  New  York,  N.  Y. 

Ping-pong  balls  are  made  of  cellulose  nitrate,  the 
first  commercially  produced  plastics.  This  plastics  ma- 
terial is  supplied  to  fabricators  in  the  form  of  white, 
opaque  sheets,  generally  .020"  thick,  and  50"  by  20"  in 
sise.  Material  manufacturers  are:  Celanese  Plastics 
Corp.,  180  Madison  Ave.,  New  York;  E.  I.  du  Pont  de 
Nemours  6-  Co.,  Inc.,  626  Schuyler  Ave.,  Arlington, 
N.  /.;  Monsanto  Chemical  Co.,  Springfield,  Mass.; 
Nixon  Nitration  Works,  Nixon,  N.  J. 


DISTRIBUTED    BY 


Beautifully  formed,  glistening  white,  realistic,  snow-like  ornaments  of 
plastic.  Light  as  a  feather  and  unbreakable.  Available  in  a  variety 
of  shapes  and  styles — special  designs  made  to  order.  (See  front 
cover  of  this  issue)  .  .  .  "No-Kink"  plastic  telephone  and  electric 
appliance  cord  covers.  .  .  .  Plastic  switch  plate  shields  .  .  .  Other 
plastic  utility  items  and  novelties.  Write  for  catalog  sheers  and  prices. 


PLASTICS 


PAPER  PRODUCTS  CORPORATION 


2941    EAST    WARREN    •    DETROIT    7.    MICHIGAN 


PRINTED  IN  U.  S.  A 


102 


I)K(  KMHKK  1946 


WHYGOTOA 
CUSTOM    MOULDER? 

«^r     ^H 

•    fl  V    ^H  ^^      ' 

Moulding  for  others  is  our  sole  source  of  business.  We  neither  design, 

mould  nor  merchandise  a  single  item  of  our  own.  Your  products  are 
the  only  ones  we  produce.  Your  problems  are  the  only  ones  we  invite. 
Our  plant  is  the  largest  in  the  East  devoted  exclusively  to  custom  injec- 
tion moulding;  and  you,  as  a  customer,  receive  the  full  benefit  of  our 
specialized  experience,  our  complete  facilities  and  abundant  capacity. 
Maybe  there's  an  idea  here  for  you  when  the  question  of  developing 
a  new  product  or  improving  an  old  one  arises. 

A  small,  condensed,  illustrated  folder, 
which  further  explains  why  you  should 
go  to  a  custom  moulder,  is  yours  /or 
the  asking. 


WORCESTER  MOULDED  PLASTICS  CO. 

14  HYGEIA  STREET,  WORCESTER  8,  MASS. 

IT   East  42nd  St.,   New  York   IT,  N.  Y. 
130  West  Chippewj   St.,   Buffalo   2,  N.  Y. 


(e 


en  by  Eberhard   Faber 
package  by  Brilhart 


in   compression,  injection,  transfer 
in^1  and    precision  machining 


ARNOUO 


BOX     31      •     MINEOLA,     N.Y. 


\ 


Date  Due