PLASTICS AND METALS — SCRIBNER 173 



The thermoplastic group is the one that constantly fills the head- 

 lines and carries most of the glamour today. It is the one that fur- 

 nishes the shoe soles, the shower curtains, the transparent food pack- 

 ages, and so on. In it are the acrylates of bomber-nose fame, styrene, 

 polyethylene, nylon, vinylidene chloride, and the vinyl family — a 

 most versatile group of chemical relatives who can do almost any- 

 thing, including belonging to either the thermosetting or thermo- 

 plastic class at the command of the chemist in charge. 



Then comes the cellulosic section, made up of cellulose acetate, cellu- 

 lose nitrate (the forefather of them all, but a frequent problem be- 

 cause of its inflammability), cellulose acetate butyrate, and ethyl 

 cellulose, one of the latest comers. These are not resins, but com- 

 pounds. Each has been loaded down with a lubricating agent, of 

 which the chemist has a list of a couple of hundred at his fingertips. 



Finally there is that catch-all class, the naturals. Nature uses 

 the same general formula that the plastics industry uses. All things 

 inanimate that grow consist of a filler (cellulose) and a binder (some 

 sort of lignin). That binder has tempted the chemist mightily ever 

 since plastics became good headline materials. Coffee, soy beans, 

 cashew nuts, walnuts, redwood, all have been found to have possi- 

 bilities. All seem to contain something resembling aldehydes or 

 phenols in their composition. They have been successful in coatings 

 and in large sheets for wall boards but the basic formula is not con- 

 sistent enough to show any particular promise in molding. 



If the field of competition between plastics and metals is small, the 

 question naturally comes up as to whether metals and plastics should 

 merely pass each other by with a nod. Definitely not. The main use 

 of plastics today and in the future is complementary to metals. 



Plastics must add to metals the characteristics that metals lack, 

 and they are already doing just this in many surprising ways. Plas- 

 tic quick-drying varnishes put the automobile into the low-price class 

 it had to hit if it wanted volume. Remember when it took weeks to 

 finish a repaint job? Busy weeks too, on the part of the painter, 

 weeks spent in rubbing down successive coats and careful drying in 

 between. Now the dipped or spray sections are dried progressively 

 in tunnels. Imagine, if you can, thousands of cars per day under the 

 old system. 



In automobile hardware we have the ideal illustration of the com- 

 bination of desirable qualities in metals and plastics — die-cast zinc 

 alloy cores for door handles covered with thermoplastic colors, warm 

 to the touch and everlasting, the strength and rigidity of the die- 

 cast metal counteracting the tendency of the plastic to droop in heat 

 or under too much pressure. Business machines of all kinds have 

 metal bases for rigidity, metal gears for small, strong sections, and 



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