Kao Corporation

Shigeki Nagashima

Nobuyuki Takizawa

Yasuhiro Doi

Takehiro Tsutsumi

Yukihiro Nakano

Yasushi Ito

Koji Azuma

Hirotaka Takeno

Yuki Wakabayashi

Michitaka Sawada

Hiroki Kubo

The present invention relates to a water dispersion for ink-jet printing including two kinds of carbon blacks (a) and (b) and a water-insoluble polymer which adheres to a surface of the respective carbon blacks (a) and (b), wherein the carbon black (a) has an acid group content of from 0 to 200 &#x3bc;mol/g and the carbon black (b) has an acid group content of more than 200 &#x3bc;mol/g but not more than 1000 &#x3bc;mol/g, and a difference between acid group contents of the carbon blacks (a) and (b) is from 100 to 1000 &#x3bc;mol/g, and a water-based ink for ink-jet printing which contains the water dispersion. The water-based ink is excellent in image density, fixing property, high lighter fastness, image uniformity, ejection reliability and storage stability.

Water-based ink for ink-jet recording

The present invention relates to a water-based ink for ink-jet printing which not only satisfies a high optical density but also exhibits an excellent high lighter-fastness; a water dispersion used for the water-based ink; and a method for producing a print using the water-based ink. There are provided a water dispersion for ink-jet printing comprising (i) (A-1) polymer particles containing a colorant, (B) polymer particles and (C) the water-insoluble organic compound, or (ii) (A-2) self-dispersible pigment, (B) polymer particles and (C) the water-insoluble organic compound; a water-based ink containing the water dispersion; and a method for producing a print using the water-based ink.

Water-based inks for ink-jet printing

The present invention relates to a water-based ink for ink-jet printing which not only satisfies a high optical density but also exhibits excellent high lighter-fastness and gloss; and a water dispersion used for the water-based ink. There are provided a water dispersion for ink-jet printing containing (A) a self-dispersible pigment, (B) self-emulsifiable polymer particles containing a constitutional unit derived from a salt-forming group-containing monomer, and (C) emulsion polymer particles; and a water-based ink containing the water dispersion.

A polymeric dispersant containing a vinyl polymer having a constitutional unit represented by the following formula 1: wherein Ris a hydrogen atom or a methyl group, Rand Rmay be the same or different and are each independently an alkylene group having from 2 to 18 carbon atoms or an arylene group having from 6 to 18 carbon atoms, Ris an alkylene group having from 4 to 18 carbon atoms or an arylene group having from 6 to 18 carbon atoms, Mand Mmay be the same or different and are each independently a hydrogen atom or a cation, k and m may be the same or different and are each independently a number from 0 to 20, and L is a number from 1 to 20, with the proviso that L is 2 or more when k is zero. The polymeric dispersant is used for the production of a water dispersion for ink-jet printing. The water dispersion for ink-jet printing is used for the production of a water-based ink for ink-jet printing.

Polymeric dispersants

An ink set comprising a black ink and a color ink, wherein the black ink comprises an aqueous dispersion of water-insoluble vinyl polymer particles containing an oil-soluble black dye or carbon black, the vinyl polymer particles have an ionicity opposite to that of the color ink, and the vinyl polymer comprises a water-insoluble vinyl polymer prepared by copolymerizing (a) a salt forming group-containing monomer, (b) a monomer represented by the formula (I):CH&#x2550;C(R)COO(RO)R&#x2003;&#x2003;(I)wherein Ris hydrogen atom or a lower alkyl group, Ris a divalent hydrocarbon group which may have a hetero-atom, Ris a monovalent hydrocarbon group which may have a hetero-atom, and p is a number of 1 to 60, (c) a macromer, and (d) a monomer copolymerizable with these monomers. The ink set can be used as an ink set for inkjet recording, which is excellent in not only fixing abilities and water resistance, but also bleeding resistance and jettability, and can form very clear printouts.

Ink set

The present invention relates to an aqueous ink for ink jet printer recording including a water dispersion of water-insoluble vinyl polymer particles containing carbon black, wherein the carbon black has a volatile content of 5% or less at 950&#xb0; C. and includes at least two kinds of carbon black differing from each other in at least one of a primary particle diameter, a specific surface area and a DBP absorption amount.

Aqueous ink for ink jet printer recording

The present invention relates to an aqueous ink for ink jet recording and a water dispersion for ink jet recording, including water-insoluble vinyl polymer particles containing a colorant, the water-insoluble vinyl polymer being a water-insoluble vinyl polymer obtained by polymerizing a monomer mixture of: wherein Rrepresents a hydrogen atom or a lower alkyl group, Rrepresents an alkylene group having 2 to 18 carbon atoms or an alkylene group having 2 to 4 carbon atoms in which a phenyl group is substituted for a hydrogen atom thereof, n denotes a number from 2 to 30 and Rrepresents a straight or branched alkyl group having 8 to 30 carbon atoms;

Water dispersion and ink jet recording ink

A water-based ink composition comprising (A) an aqueous medium; (B) at least one colorant selected from the group consisting of (i) polymer particles comprising a dye or pigment and a water-insoluble polymer, and (ii) a self-dispersible pigment; and (C) a specific compound A. The water-based ink composition is used for inkjet printing.

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Wakayama, Japan

Shigeki Nagashima