| 摘要 |
559,676. Polyamides. DU PONT DE NEMOURS & CO., E. I. July 2, 1941, No. 8324. Convention date, July 2, 1940. [Class 2 (iii)] The stiffness, durability &c. of filaments, bristles, films, coatings and like bodies made from polyamides of the kind described in Specifications 461,236 and 461,237 is improved by treatment with substances containing one or more groups -N =C =X, where X is sulphur or oxygen, e.g. isocyanate or isothiocyanates, preferably diisocyanates. The treatment consists in the immersion of the polyamide body in the pure isocyanate, at 80-140‹C. or immersion in the isocyanate diluted with toluene or like hydrocarbon solvents followed by heating at 180-220‹C. Catalysts, e.g. metallic driers may be used to accelerate the reaction. Specification 504,344 also is referred to.
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