PROCESS FOR PREPARING RIGID POLYURETHANE FOAMS

摘要

Process for the preparation of a rigid polyurethane or urethane-modified polyisocyanurate foam in the presence of a blowing agent mixture comprising cyclopentane and a certain amount of other organic compounds as co-blowing agents, the saturated vapour pressure of said co-blowing agents in bar at Tuse (v.p.) complying with the following equation (I): v.p. >/= 0.7 bar x Tuse/298 DEG K x C/100 wherein C is the mole % of said co-blowing agent in gaseous form on the total blowing agent mixture in the gaseous phase after foaming and Tuse is the temperature in DEG K at which the foam is used.