| abstract |
A process for preparing polymer emulsion particles having pores therein, an outside diameter D of 0.1 to 5.0[ , an inside diameter d of 0.05 to 4.0μ , and a ratio (d/D) of 0.1 to 0.9 in dry condition, comprising the steps of forming core-shell emulsion particles from specific monomers by two-emulsion polymerizations, and swelling the core of the particles with water by hydrolyzing the vinyl acetate part of polymer (A), thereby inducing the hydroxyl groups therein, e.g., using an acidic material or a basic material at 50° to 100° C. The particles when use as a pigment in coating compositions provide excellent converage rate, brightness, gloss and water resistance. |