Patent ID: 6635706
Filing Date: 2003-10-21
Classification: C08F,C08G,C09D,Y10S

Abstract:
A stable precrosslinked, urethane-acrylic hybrid polymer dispersion formed by:(a) blending: (i) an isocyanate terminated urethane prepolymer which is the reaction product of monomeric diisocyanate and active hydrogen containing materials having from 1.8 to 3.0 active hydrogens per molecule and molecular weight of 62 to 5000, and having an NCO content of 1.0 to 1.9% by weight. (ii) a polyisocyanate equal to 0.5 to 20 % of the solids by weight of (i) and (ii) and having an average isocyanate functionality of less than 4.0, and (iii) one or more vinyl monomers inert to isocyanate functionality, and (b) reacting 0 to 100% of the isocyanate groups of the urethane prepolymer (i) and polyisocyanate (ii) in blend (a) with a monofunctional active hydrogen containing vinyl monomer, and (c) dispersing (b) into water, (d) chain extending residual isocyanate groups of the prepolymer with one or more active hydrogen containing compounds, and (e) reacting the vinyl groups of the blend by free radical polymerization.