METHOD FOR PRODUCING RIGID POLYURETHANE FOAM

摘要

A method for producing a rigid polyurethane foam, which comprises mixing (a) a polyisocyanate component with a polyol component comprising (b) a polyol mixture, (c) a catalyst and (d) a blowing agent, then foaming the mixture; wherein the polyisocyanate component (a) is polymethylenepolyphenyl polyisocyanate or a modified material thereof; the polyol mixture (b) comprises (b-1) a polyol which is produced by adding an alkylene oxide to an aliphatic amine and (b-2) an aromatic polyether polyol which is produced by using an aromatic amine, a Mannich base having an aromatic ring or a polyfunctional phenol as a starting material; the catalyst (c) is at least one metallic catalyst and the blowing agent (d) is an adduct of a primary or secondary amine compound with carbon dioxide. The method of the present invention is superior in initial activity and requires a small amount of raw materials.