Stabilized dispersion of cross-linked polymer particles

Claim 1

A stable dispersion containing crosslinked polymer particles characterized in that they are formed by reactions comprising addition polymerization of: (a) between about 0.5 and about 20 weight percent each of a first and second monomer selected from (i) first and second ethylenically unsaturated monomers each bearing functionality capable of crosslinking reaction with the other or (ii) first and second monomers, wherein said first monomer bears ethylenic unsaturation and functionality capable of crosslinking reaction with other functionality present on said second monomer, said second monomer bearing at least two functional groups of said other functionality and bearing no ethylenic unsaturation; and (b) between about 99 and about 60 weight percent of at least one other monoethylenically unsaturated monomer. in the presence of (I) an organic liquid which is a solvent for the polymerizable monomers, but a non-solvent for the resultant polymer, and (II) polymeric dispersion stabilizer, wherein the reaction is carried out at elevated temperatures such that the dispersion polymer is first formed and then is crosslinked, said dispersion stabilizer comprising, on the average, more than one long hydrocarbon chain and at least one vinyl unsaturation and being the reaction product of: (A) an adduct bearing pendant hydroxyl groups and being the reaction product of: (a) long chain hydrocarbon molecules bearing a carboxyl group and no other reactive group; and (b) polyepoxide resin having (i) at least two epoxide groups and (ii) a number average molecular weight of between about 140 and 3000, reacted in amounts so as to provide greater than about 1.0 mole of said long chain hydrocarbon molecules bearing a carboxyl group for each mole of said polyepoxide resin; and (B) ethylenically unsaturated monoisocyanates, wherein said adduct and said ethylenically unsaturated monoisocyanates are reacted in amounts so as to provide at least about 1.0 mole of said monoisocyanate for each mole of said polyepoxide resin employed in said stabilizer formation.