Patent ID: 8703865
Filing Date: 2014-04-22
Classification: C09B,C09D

Abstract:
1. A method of producing an aqueous dispersion of polymer-encapsulated pigment, comprising the steps of: (a) preparing an aqueous pigment dispersion comprising at least one organic pigment P selected from the group consisting of azo, isoindolinone, isoindoline, anthanthrone, thioindigo, thiazineindigo, triarylcarbonium, quinophthalone, anthraquinone, dioxazine, phthalocyanine, quinacridone, quinacridonequinone, indanthrone, perylene, perinone, pyranthrone, diketopyrrolopyrrole, isoviolanthrone, and azomethine pigments, at least one surfactant T, and water; (b) providing a monomer miniemulsion stabilized by a hydrophobic organic compound having a water solubility at 20° C. of not more than 5×10 (c) producing a pigment-containing monomer miniemulsion by combining and homogenizing the aqueous pigment dispersion from step (a) and the monomer miniemulsion from step (b), and (d) polymerizing the pigment-containing monomer miniemulsion from step (c) in the presence of a polymerization initiator by heat or both to form the polymer-encapsulated pigment, wherein the polymer-encapsulated pigment has a homopolymer content of less than 5% by weight based on the total weight of the encapsulated pigment particles.