Rigid polyisocyanurate foams are prepared by (a) bringing together on a continuously advancing conveyor an organic polyisocyanate, a minor amount of a polyester polyol, a blowing agent and, in an organic solvent, a catalyst mixture comprising: (i) a salt of a low molecular weight carboxylic acid selected from the group consisting of an alkali metal salt and an alkaline earth metal salt and mixtures thereof, and (ii) a tertiary amine, the amount of the salt of the low molecular weight carboxylic acid being sufficient and the molecular weight of the carboxylic acid of the salt being sufficiently low to provide a firm foam having a nonfriable surface, and (b) foaming the foam-forming mixture.
硬质聚异
氰脲酸
酯泡沫的制备方法是:(a) 在连续推进的传送带上将有机多
异氰酸酯、少量聚
酯多元醇、发泡剂和在有机溶剂中的
催化剂混合物混合在一起,
催化剂混合物包括:(i) 低分子量
羧酸盐,该盐选自碱
金属盐和碱土
金属盐及其混合物组成的组,以及 (ii) 三级胺,低分子量
羧酸盐的用量要足够大,盐的
羧酸分子量要足够低,以提供具有不易碎表面的坚固泡沫;(b) 将发泡混合物发泡。