PROCESS FOR PRODUCING AQUEOUS PIGMENT DISPERSION AND INK FOR INK-JET RECORDING

摘要

A process for highly efficiently producing an aqueous pigment dispersion containing an azo dye. The dispersion can retain a stable dispersion state over long and is suitable for use in inks for ink-jet recording. The process for aqueous pigment dispersion production comprises a liquefaction step in which a solid kneaded mixture obtained by mixing a solid kneaded mixture comprising one or more pigments (a) consisting mainly of an azo pigment, a styrene/acrylic acid copolymer (b), a basic compound (c), and a wetting agent (d1) with an aqueous medium is kneaded and water (e) and a wetting agent (d2) are added to the mixture being kneaded to thereby make the mixture liquid, the total amount of the wetting agent (d2) to be added in the liquefaction step being 0.5-40 mass% based on the solid kneaded mixture at the time of initiation of the liquefaction step.