Dic Corporation

Soetrisno Misawa

Shinichi Okada

Yoshinosuke Shimamura

Yukihiko Kawaharada

Atsuo Kobayashi

Hiroyuki Buei

Masahiro Kido

A highly efficient method is provided for producing a water-based ink for ink jet recording with which the number of coarse particles in a water-based pigment dispersion liquid is significantly reduced, dispersed particles are made finer, the dispersion stability is improved, the storage stability is improved, and high discharge stability is achieved when a water-based ink for ink jet recording is produced. Particularly, provided is a method for producing a water-based pigment dispersion liquid, the method including kneading a mixture containing a quinacridone type pigment (a), a styrene-acrylic acid type copolymer (c), a basic compound (d), and a polyoxyalkylene glycol or its derivative (e) to prepare a pigment dispersion that is solid at room temperature and mixing a aqueous medium and the pigment dispersion to decrease the viscosity and liquefy the pigment dispersion.

Method for producing water-based pigment dispersion liquid and water-based ink for ink jet recording

Disclosed are an ink jet recording water-based ink having excellent long-term storage stability and ejection stability at a pigment concentration greater than or equal to a certain level and a simple and efficient method for producing such a water-based ink. The present invention provides an ink jet recording water-based ink in which the total content of polyvalent metals as impurities in the water-based ink is not more than 1.2 ppm in terms of 1 mass % of a pigment concentration. Furthermore, the present invention provides a method for producing an ink jet recording water-based ink; the method enables efficient production of the above-mentioned ink jet recording water-based ink through a contact treatment with a particulate chelating resin in which each resin particle contains both an alkali metal-bonded chelating group and a hydrogen-bonded chelating group.

Ink jet recording water-based ink and method for producing the same

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Jakarta, Indonesia

Soetrisno Misawa