Dainippon Ink and Chemicals, Incorporated

Dic Corporation

Kazuhiro Kaneko

Hiromichi Arakawa

Hiroshi Harada

Shinichi Okada

Yoshinosuke Shimamura

Sadahiro Inoue

Shigehiro Tanaka

Akio Kumagai

Hideaki Kaji

Ritsuko Small

Disclosed is an ink composition for jet printer, comprising a pigment, a film forming resin and an organic solvent, the film forming resin being an acrylic copolymer containing, as a monomer unit, at least one of compounds represented by the general formulas (1) and (2): wherein Rrepresents a hydrogen atom or a methyl group; Rrepresents an alkylene group having 2 to 12 carbon atoms which may be linear or branched; and Rand Reach independently represents a hydrogen atom, an alkyl group, an alkenyl group or an aryl group, and the sum of the number of carbon atoms of Rand Ris from 4 to 12, or Rand Rform a saturated or unsaturated hydrocarbon group which is a five-membered ring formed by combination of the Rand R; and wherein Rrepresents a hydrogen atom or a methyl group; Rrepresents an alkylene group having 2 to 12 carbon atoms which may be linear or branched; and X represents a group selected from the group consisting of groups represented by the general formulas (3) to (9).

Ink composition for jet printer

A process is provided for producing aqueous pigment dispersions for ink-jet recording in which fine pigments are stably dispersed and such a state can be maintained for a long period of storing. Moreover, a process is provided for producing aqueous pigment dispersions for ink-jet recording in which the time required for production such as dispersing time is short, and the production efficiency is high. The process for producing aqueous pigment dispersions for ink-jet recording includes a first step of kneading (1) a styrene-acrylic type resin with a styrene type monomer unit of 50 to 90 mass %, and at least one unit selected from an acrylic monomer unit and methacrylic monomer unit, having an acid value of 50 to 300, (2) a pigment, (3) a basic compound, and (4) a humectant to produce a solid colored kneaded product, and a second step of dispersing the solid colored kneaded product in an aqueous medium comprising water or water and humectant.

Process for producing aqueous pigment dispersions for ink-jet recording

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Osaka, Japan

Kazuhiro Kaneko