Patent ID: 8034322

Claim:
A process for preparing an aqueous polyurethane dispersion suitable for use in personal care products, comprising: 1) preparing a prepolymer according to the formula: wherein R 1 represents a bivalent radical of a polycarbonate polyol, R 2 represents a radical of an aliphatic or cycloaliphatic polyisocyanate, R 3 represents a radical of a low molecular weight diol, optionally substituted with ionic groups, n is from 1 to 5, and m is >1; by reacting: 1a) at least one polycarbonate polyol, 1b) one or more aliphatic or cycloaliphatic polyisocyanates, and 1c) at least one low molecular weight diol optionally substituted with ionic groups; 2) reacting the prepolymer with at least one monohydroxyl-functional polyalkylene oxide with a number average molecular weight equal to or less than about 3,000; 3) chain-extending the prepolymer with 3a) at least one chain extender according to the formula: H 2 N—R 4 —NH 2 wherein R 4 represents an alkylene or alkylene oxide radical not substituted with ionic or potentially ionic groups, and 3b) at least one chain extender selected from the group consisting of the sodium salt of N-(2-aminoethyl)-2-aminoethane sulfonic acid and compounds according to the formula: H 2 N—R 5 —NH 2 wherein R 5 represents an alkylene radical substituted with ionic or potentially ionic groups, in the presence of an organic solvent to form a polyurethane; 4) dispersing the polyurethane in water; and 5) removing the organic solvent, resulting in an aqueous polyurethane dispersion; wherein the radical of the monohydroxyl-functional polyalkylene oxide constitutes between about 0.1 wt. % to about 5 wt. % of the polyurethane.