MANUFACTURING: Hot Rayon

Inside an automobile tire streaking along at 50 or 60 miles an hour, the temperature often hits 220° F. This heat bakes the cotton cord, makes the whole tire wear out. After years of searching for a heat-resisting fabric, several manufacturers have lately experimented with rayon. Unlike cotton, which grows weaker under heat, rayon grows stronger (up to about 175°); at 200° it has about 45% more tensile strength than cotton. Last month, a U. S. Rubber Co. subsidiary brought out the first rayon-cord passenger-car tire. Last week, Goodyear Tire & Rubber Co. followed suit.

Both U. S. Rubber’s and Goodyear’s rayon tires will sell for more than the similar articles made with cotton. But both companies claim that four-ply rayon is as sturdy as six-ply cotton. Should rayon ultimately prove more practical, U. S. cotton farmers will lose one of their biggest customers: last year the rubber industry bought some 283,750,000 lb. of cotton, used an average of 5 lb. per tire.