METHOD FOR PRODUCING PIGMENT DISPERSION

PROBLEM TO BE SOLVED: To provide a pigment dispersion in which a commercially available pigment can be used and an aqueous coating or ink using the dispersion is excellent in long-term storage stability and provides a coating film or printed matter with a high optical density (OD), good scratch resistance and water resistance. SOLUTION: The method for producing the pigment dispersion comprises: (1) a first step of neutralizing with a base a part or all of acid groups in a resin which has a weight average molecular weight (Mw) in the range of 9,000-80,000 and has acid groups and then emulsifying or suspending the resin into an aqueous medium to obtain a resin dispersion having an average particle size of the resin in the range of 0.01-1 μm; (2) a second step of adding a pigment to the resin obtained in the first step and then grinding the mixture; and (3) a third step of further finely-dividing the ground matter obtained in the second step with a homogenizer. COPYRIGHT: (C)2005,JPO&NCIPI