PROCESS FOR THE PRODUCTION OF HARD POLYURETHANE FOAMS

摘要

Method for the preparation of rigid polyurethane foams Rigid polyurethane foams are prepared by the reaction of 1) polyisocyanates with 2) compounds of a molecular weight of from 150 to 1500, having at least two hydrogen atoms active towards isocyanates and which one tertiary nitrogen atom in the molecule, in the presence of 3) hydrofluoroalkanes as foaming agents as well as optionally in the presence of 4) other auxiliary substances and additives known per se.