Patent ID: 11066564

Abstract:
The present invention relates to a water-based pigment dispersion containing a polymer dispersant and a pigment, the polymer dispersant being prepared by crosslinking a carboxy group-containing water-insoluble polymer (A) with a water-insoluble polyfunctional epoxy compound, in which carboxy groups of the water-insoluble polymer (A) are at least partially neutralized by an alkali metal compound, and the water-based pigment dispersion satisfies the following conditions 1 to 3. The water-based pigment dispersion of the present invention can exhibit excellent redispersibility capable of suppressing solidification of the pigment or the polymer in ink ejection nozzles and can ensure good storage stability under high-temperature conditions. The conditions 1 to 3 are as follows: Condition 1: a value calculated according to the formula: {[100−(neutralization degree)−(crosslinking degree)]/100}×[acid value of water-insoluble polymer (A)] is from −30 to 30 mgKOH/g: Condition 2: a value calculated according to the formula: [(neutralization degree)/100]×[acid value of water-insoluble polymer (A)] is from 80 to 180 mgKOH/g; and Condition 3: a value calculated according to the formula: [(crosslinking degree)/100]×[acid value of water-insoluble polymer (A)] is from 80 to 180 mgKOH/g.