| 摘要 |
520,263. Polyamides. DU PONT DE NEMOURS & CO., E. I. Oct. 28, 1938, No. 31200. Convention date, Nov. 9, 1937. [Class 2 (iii)] Refers to diamine-dibasic acid polyamides, as described in Specification 461,237, and consists in converting the half-made polyamide to a superpolyamide by heating the former in the solid state and preferably in finely-divided condition to a polymerizing temperature which is below (preferably 2-20‹C.) the melting-point, as determined by the fusion method in the absence of oxygen. In an example hexamethylene diammonium adipate, with a little adipic acid and hexamethylene diammonium acetate and water is heated to 225‹C. in an autoclave and the half-made polymer so prepared is then heated in the solid state to 259‹C. The invention may be applied to mixtures of polyamides, interpolymers, or polyamide compositions containing modifying agents, e.g., plasticizers, resins, pigments, dyestuffs, &c. Specifications 474,999, 495,790 and 506,125 also are referred to. |
