Production manner null of halogen content resistance to flame resin foaming

摘要

PURPOSE:To produce an expansion-molded article free from discoloration at a lower molding temperature than conventional injection molding process, by mixing phthalic anhydride to azodicarbonamide used as a foaming agent, adding the mixture to a halogen-containing flame-retardant resin and injection-molding the obtained resin composition. CONSTITUTION:A halogen-containing flame-retardant resin (e.g. polystyrene, ABS, polyamide, polyester, etc., compounded with a bromine-based flame- retardant, etc., a vinyl chloride resin, etc.) is mixed with a mixture of (A) 0.3-0.7wt% azodicarbonamide and (B) 0.5-4% phthalic anhydride and the resultant resin composition is injection-molded to obtain the objective expansion- molded article. The discoloration of the expansion-molded article hardly occurs because the amine generated above the decomposition initiation temperature of the component A reacts first with phthalic anhydride to inhibit the dehalogenation of the resin.