PROCESS FOR RIGID POLYURETHANE FOAMS

摘要

Process for preparing rigid polyurethane or urethane-modified polyisocyanurate foams comprising the step of reacting an organic polyisocyanate with a polyfunctional isocyanate-reactive component in the presence of a blowing agent mixture comprising from 50 to 90 % by weight of cyclopentane and from 10 to 50 % by weight of a mixture comprising isopentane and/or n-pentane and isobutane and/or n-butane wherein the weight ratio of isopentane and/or npentane over isobutane and/or n-butane is between 5/95 and 95/5.