Process for rigid polyurethane foams

摘要

Process for preparing rigid polyurethane or urethane-modified polyisocyanurate foams by reacting an organic polyisocyanate with a polyfunctional isocyanate-reactive component comprising more than 2 % by weight of water and from 5 to 50 % by weight of polyester polyols of average functionality below 3, especially crude polyester polyols.