POLYURETHANE DISPERSIONS WITH HIGH ACID CONTENT

摘要

A polyurethane dispersion prepared by: A) forming an isocyanate functional prepolymer containing acid functional groups by reacting a first polyol, a second polyol having carboxylic acid functionality and a polyisocyanate; and optionally B) reacting an amino acid with the prepolymer. The dispersion is used in coating compositions that include (i) the above-described polyurethane dispersion and (ii) a cross-linking agent for the polyurethane which does not contain free isocyanate groups. The coating composition is used to coat substrates by: (a) mixing components (i) and (ii); and (b) applying the mixture to a surface of the substrate.