Patent ID: 6911487

Claim:
A process for making a polymer dispersion, comprising (a) forming a mixture of an isocyanate-terminated prepolymer substantially devoid of acid or ionic groups and at least one monomer having at least one site of polymerizable carbon-carbon unsaturation and which monomer is a liquid or solid at room temperature, the prepolymer being soluble in the monomers at the relative proportions that are present; (b) dispersing the mixture into an aqueous phase under conditions sufficient to form an aqueous dispersion of a plurality of stabilized droplets that have an average diameter of no greater than about 1000 nm and contain both the prepolymer and the monomer(s), and (c) subjecting the dispersion from step (b) to conditions sufficient to polymerize the monomer(s) and chain-extend said prepolymer in a single step to form a plurality of hybrid polymer/polyurethane particles having an average diameter of no greater than about 1000 nm dispersed in said aqueous phase, and wherein the hybrid particles have a particle size that differs from the size of the stabilized droplets formed in step (b) by no more than 10%.