Polyamide Resin Foam

摘要

1,178,784. Cross-linked polyamide foams. TOYO RAYON K.K. 14 Feb., 1968 [18 Feb., 1967; 15 May, 1967], No. 7326/68. Headings C3C and C3G. A foam comprises a polyamide having a gel percentage (which is defined in the Specification) of at least 40% by wt., cross-linked by graft polymerization with an organic compound having at least two double bonds in the molecule and has at least 50% by vol. of closed cells, an average cell size of 10-800 Á and a density of 0À02-0À5. The foam may be prepared by mixing the polyamide, the organic compound and a heat decomposable foaming agent at a temperature higher than the softening point of the polyamide, irradiating the mixture with 0À5-30 megarads of ionizing rays and heating the mixture to foam the polyamide. The polyamide may be a copolymer of #-caprolactam and hexamethylene diammonium adipate and/or sebacate with optionally lauryl lactam, polylauryl lactam or polycaprolactam. The organic compound may be diallyl phthalate, maleate, adipate, sebacate, succinate, or itaconate; diethylene glycol diacrylate, triailyl cyanurate, N,N1 - methylenebisacrylamide, N,N1 - hexamethylenebisacrylamide, N,N1 - phenylenebismethacrylamide, N - methyl - N - allylacrylamide, or N,N1 - diphenyl - or propyl - N,N1 - hexamethylenebisacrylamide. The foaming agent may be azodicarbonamide, barium azodicarboxylate, trihydrazino - sym - triazine, hydrazodicarbonamide, 4,41 - oxybis (benzenesulphonylsemicarbazide) or N,N1 -dinitrosorentamethylene tetramine. The ionizing rays may be electron or gamma rays. The foam may be in the form of a sheet.