Polyisocyanurate rigid foams.

摘要

A method for the preparation of a polyisocyanurate foam which comprises reacting a polymethylene polyphenylene polyisocyanate composition with a polyfunctional active hydrogen compound in the presence of a trimerisation catalyst and an inert volatile blowing agent, the isocyanate index being at least 750 and the weight of polyisocyanate composition being at least 80 % of the combined weights of the polyisocyanate composition and active hydrogen compound.