Process for producing polyisocyanurate foams

摘要

A process for producing polyisocyanurate foam which comprises reacting an organic polyisocyanate with a polyol and water in the presence of a halogen-free aliphatic phosphoric ester having a molecular weight of 140 to 270 and a trimerization catalyst. Polyisocyanurate foams having good adhesion to membrane such as paper, iron, aluminium, plywood and the like can be obtained without use of an volatile blowing agent such as CFCs, HCFCs and HFCs and even at low density according to the present process.