Urethane-modified polyisocyanurate rigid foam

Abstract From the Canadian patent

Improved crack-free rigid cellular polyisocyanurate polymers are disclosed that are derived from the reaction of an organic polyisocyanate combination comprising two particular types of polymethylene polyphenyl polyisocyanates (a) and (b), a trimerization catalyst minor, amount of a polyol, a surfactant and an inert volatile, blowing agent having a boiling point from about 30°C to about 90°C. The novel rigid foams are particularly useful in preparing high molded bodies of foam by making multiple pours or lifts on top of each other in a mold. The resultant molded body comprises a multiple of molded parts firmly fused to each other and crack-free. Such high molded bodies and process therefor …