Abstract: Low density polyurethane foams having improved resistance to degradation of properties of compression set and flexibility when exposed to elevated temperatures and pressures are made by reacting a polyisocyanate of about 2.3 to 2.7 functionality at an isocyanate index of about 1.0 with a blend of polyols, catalysts, blowing agents and the like in which the polyols are a mixture of a polyether polyol having a molecular weight of at least 5,000 and a polymer polyol, and the catalysts are a mixture of a major portion of an amine catalyst and a minor portion of a metal catalyst. The foams made by this invention are particularly well suited for use as components of sport shoes that are asembled by vulcanization.

Abstract: A method for the manufacture of shock attenuating, low rebound polyurethanes in which polyols are reacted with polyisocyanates having a functionality of at least 2.3 at an isocyanate index of from about 65 to about 90.