Prepn. of polyurethane rigid foam

摘要

Process comprises combining an organic polyisocyanate, an organic polyol, a halogenated alkane expanding agent, a surfactant and a catalyst for reaction of the -OH and -NCO radicals. Prodn. of a digestion prod. soluble in acetone at ambient temp., permits recovery in an open tank of rigid foam of relatively reduced total density, high shear and compressive strength and flame retardancy. - The organic polyisocyanate is a polymer polyisocyanate, the polyol is a polyester or mixt. of polyester contg. 50 wt.% of a halogenated polyol consisting of chlorinated or brominated polyesters, with trichlorofluoromethane as expanding agent, alkoxylated silicone as surfactant, and an amine or tin catalyst.