Polyurethane-modified polyisocyanurate foam and method for producing the same

Abstract From the Canadian patent

A polyurethane-modified polyisocyanurate foam having an excellent heat-resistance and flame-resistance and a reduced smoke-generation, comprises a reaction product of a mixture containing (A) at least one polyisocyanate compounds; (B) at least one polyol compound including benzylic ether type phenolic resin of the formula (1): (1), wherein R=H , hydrocarbon, oxyhydrocarbon or halogen X = H, or methylol, the molar ratio methylol/H ? 1 m+n ? 2 and, m/m ? 1; p=1?3, (C) a trimerization catalyst and; (D) a, blowing agent, the ratio of the isocyanate equivalent of the isocyanate compound to the hydroxyl equivalent of the polyol compound being from 1.5 t 10.