POLYURETHANE PREPOLYMER COMPOSITIONS, FOAMS MADE THEREFROM AND METHODS OF MAKING EACH THEREOF

摘要

A polyisocyanate prepolymer composition is comprised of the reaction product of (a) a polyisocyanate having an average functionality of at least 2 and containing at least 20 percent by weight of a diisocyanate monomer, (b) a monohydric alcohol and (c) a polyol having an average hydroxyl functionality of at least 1.8 to at most 3.2, wherein the prepolymer composition has (i) an amount of isocyanate groups by weight sufficient to react with water in the absence of a supplemental blowing agent to make a foam, (ii) at most 10.0 percent by weight of the diisocyanate monomer and (iii) an amount of the polyisocyanate that is capped by the monohydric alcohol sufficient to prevent gelling of the prepolymer composition. The prepolymer composition may be formed by contacting (i) an organic polyisocyanate having an average isocyanate functionality of at least 2.0 and an amount of diisocyanate monomer of at least 20 percent by weight, (ii) a monohydric alcohol and (iii) a polyol having an average hydroxyl functionality of at least 1.8 to at most 3.2 for a time and temperature sufficient to form the prepolymer composition, wherein the organic polyisocyanate, monohydric alcohol and polyol are contacted at a ratio of NCO to hydroxyl of at least 2, to at most 5, and the monohydric alcohol and polyol are provided in a ratio of monohydric alcohol to polyol of at least 0.1, to at most 2, based upon the hydroxyl equivalence of the monohydric alcohol and polyol. The prepolymer composition may be reacted with water to form a polyurethane foam.