AQUEOUS DISPERSIONS OF MICROPARTICLES HAVING A NANOPARTICULATE PHASE AND COATING COMPOSITIONS CONTAINING THE SAME

摘要

The present invention is directed to an aqueous dispersion of microparticles comprising nanoparticulates, and to methods of preparing the dispersion, as well as to compositions containing such dispersions. The dispersion is prepared by (a) providing a plurality of nanoparticulates having an average particle size of 300 nanometers or less; (b) admixing the nanoparticulates with a solventborne water-disperable polymer or with (1) one or more polymerizable ethylenically unsaturated monomers; and/or (2) a mixture of one or more polymerizable unsaturated monomers with one or more polymers; and/or (3) one or more polymers, to form an admixture; (c) subjecting the admixture to high stress shear conditions in the presence of either an organic solvent or an aqueous medium to particularize the admixture into microparticles; and (d) optionally, polymerizing the ethylenically unsaturated monomers under free radical polymerization conditions.