Kao Corporation

Takehiro Tsutsumi

Koji Azuma

Ryuma Mizushima

Isao Tsuru

Nobushige Tanaka

Michitaka Sawada

Nobuyuki Takizawa

Kenji Kaida

Shigemi Wakabayashi

Shigeki Nagashima

Makoto Sakakibara

Kuniyasu Kawabe

Koichi Nakamura

Shinichi Sata

Hiroshi Mizuhata

Yukihiro Nakano

Hirotaka Takeno

Tadashi Sakuma

Yuki Hidaka

Tetsuya Ueno

Kazunari Takemura

Toshiya Iwasaki

Masato Hoshi

Akira Umada

Hitoshi Hosokawa

Katsuhiko Inada

Kohji Azuma

Tooru Sugawara

The present invention relates to a process for producing a toner for electrophotography which is excellent in dispersibility of a colorant in the toner and capable of considerably improving an image density, as well as a toner for electrophotography which is produced by the process. There is provided a process for producing a toner for electrophotography which includes the step of mixing a dispersion of colorant-containing polymer particles with a dispersion of resin particles containing substantially no colorant to aggregate the colorant-containing polymer particles and the resin particles, wherein the polymer contains a constitutional unit derived from a salt-forming group-containing monomer (a) and a constitutional unit derived from an aromatic ring-containing monomer (b).

Process for producing toner for electrophotography

The present invention relates to crosslinked core/shell polymer particles containing a pigment which are usable in a water-based ink for ink-jet printing and exhibit excellent optical density and gloss and are prevented from suffering from occurrence of bronzing, wherein the polymer particles each include a core portion and a shell portion which are respectively made of a crosslinked polymer, and a weight ratio of the pigment to the pigment-containing crosslinked core/shell polymer particles [(weight of the pigment/weight of the pigment-containing crosslinked core/shell polymer particles)&#xd7;100] is from 25 to 75. The present invention further relates to a water dispersion and a water-based ink for ink-jet printing which contain the crosslinked core/shell polymer particles and a process for producing crosslinked polymer particles.

Crosslinked core/shell polymer particles

The present invention relates to (A) a water dispersion for ink-jet printing including particles of a waster-insoluble crosslinked polymer which contain a colorant, and a water-insoluble organic compound, wherein the water-insoluble crosslinked polymer is (1) a polymer produced by crosslinking a water-insoluble polymer with a crosslinking agent; (2) a polymer produced by crosslinking 100 parts by weight of the water-insoluble polymer with 0.5 to 9.5 parts by weight of the crosslinking agent; or (3) a polymer having a weight-average segment molecular weight of from 1,400 to 20,000 as calculated from [(weigh-average molecular weight of the water-insoluble polymer)/(number of molar equivalents of the crosslinking agent to be reacted with 1 mol of the water-insoluble polymer+1)]; (B) an ink for ink-jet printing containing the above water dispersion which is excellent in gloss and storage stability; and (C) particles of the water-insoluble crosslinked polymer.

Water-based inks for ink-jet printing

There are provided a water dispersion for ink-jet printing which contains a water dispersion of particles of a vinyl polymer or a polyester-based polymer which contain a colorant (B), and a water-insoluble organic compound (A) except for aliphatic acid derivatives; a water-based ink containing the water dispersion; a print obtainable by printing images or characters with the water-based ink; and a process for producing the water dispersion. Also, there are provided an ink set for ink-jet printing containing two or more kinds of inks having different colors from each other wherein the inks each contain a water dispersion of particles of a vinyl polymer or a polyester-based polymer which contain a colorant (B), and a water-insoluble organic compound (A) except for aliphatic acid derivatives; and a process for producing a print using the ink set. The water-based ink can provide multi-order color images or composite black images which exhibits a high optical density and is excellent in gloss and image clarity.

A water dispersion for inkjet printing which contains polymer particles containing a colorant. The polymer constituting the polymer particles is produced by the copolymerization of a monomer mixture in the presence of a-methylstyrene dimer. The water dispersion for inkjet printing and a water-based ink for inkjet printing containing the water dispersion exhibit excellent jetting properties and a high optical density.

Water-based ink for inkjet printing

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

Provided are a water dispersion for ink-jet printing, wherein it is a water dispersion of water-insoluble graft polymer particles containing a colorant; the above graft polymer contains a principal chain having a constitutional unit derived from a vinyl base monomer and a side chain which is derived from a macromer containing an aromatic ring and having a polymerizable functional group at one end; both of the Log P values of the above principal chain and the above side chain are positive; and a difference between both falls in a specific range, and a water-based ink containing the same. The above water-based ink is excellent in a discharge stability, a storage stability, a heat stability and a water resistance.

Water dispersion for ink-jet printing

The present invention relates to a water dispersion for ink jet recording, comprising water-insoluble vinyl polymer particles containing a colorant, wherein the water-insoluble vinyl polymer is a water-insoluble vinyl polymer obtained by polymerizing a monomer mixture comprising: wherein Rrepresents a hydrogen atom or a methyl group, Rrepresents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms or a phenyl group whose hydrogen atom may be substituted with an alkyl group having 1 to 9 carbon atoms and m denotes a number from 65 to 100;

Water dispersion for ink jet recording

The invention provides a process for producing a water dispersion for ink jet recording,which comprises the following steps 1 and 2:

Aqueous ink for ink jet recording

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

A water-based ink comprising an aqueous dispersion of polymer particles made of a water-insoluble vinyl polymer containing a colorant, wherein the water-insoluble vinyl polymer is prepared by polymerizing a monomer composition comprising a specific monomer A such as a monomer A1 represented by the formula (I): wherein Ris hydrogen or methyl, Ris hydrogen, alkyl or alkylphenyl, and n is 1 to 30; a monomer having a salt-forming group; and a monomer copolymerizable with the monomer A and the monomer having a salt-forming group. The water-based ink can be suitably used as a water-based ink for inkjet recording and the like.

Water-based ink

There are provided a water dispersion for ink-jet printing comprising colorant-containing water-insoluble graft polymer particles in which the water-insoluble graft polymer contains a main chain which is a polymer chain containing a constitutional unit derived from a salt-forming group-containing monomer (a) and a constitutional unit derived from an aromatic ring-containing (meth)acrylate monomer (b), and a side chain which is a polymer chain containing a constitutional unit derived from a hydrophobic monomer (c); a water-based ink for ink-jet printing using the water dispersion; and an ink-jet printing method using the water-based ink. In accordance with the present invention, printed images or characters formed on a coated paper are excellent in gloss, image clarity and image clarity property including both of the image clarity and the gloss, and printed images or characters formed on an ordinary paper exhibit a high print density.

An aqueous dispersion for inkjet recording containing colorant-containing water-insoluble vinyl polymer particles dispersed in water, wherein the water-insoluble vinyl polymer contains a constitutive unit derived from a styrenic macromer (a) which has a polymerizable functional group at one end, wherein the styrenic macromer (a) has a number-average molecular weight of from 1000 to 5000 and a molecular weight distribution (weight-average molecular weight/number-average molecular weight) of from 1.0 to 2.5; and a water-based ink for inkjet recording containing the aqueous dispersion. The aqueous dispersion is capable of realizing a water-based ink for inkjet recording, which has excellent storage stability, a high optical density, and gives a high gloss.

Aqueous dispersion for inkjet recording

A water-based ink containing an aqueous dispersion of water-insoluble vinyl polymer particles containing a pigment, wherein the water-insoluble vinyl polymer is prepared by copolymerizing a monomer mixture containing (a) a monomer having a salt-forming group, (b) a monomer having a long-chain alkyl group, (c) a macromer, (d) a monomer having a polyoxyalkylene group, and (e) a monomer copolymerizable with the monomer having a salt-forming group (a), the monomer having a long-chain alkyl group (b), the macromer (c) and the monomer having a polyoxyalkylene group (d). The water-based ink can be suitably used, for instance, as a water-based ink for inkjet recording and the like.

An ink set comprising at least one anionic chromatic colored ink and at least one cationic chromatic colored ink; and a recording process comprising the step of printing with an ink set comprising at least one anionic chromatic colored ink and at least one cationic chromatic colored ink. The ink set can be suitably used for a printer for inkjet recording or the like.

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Wakayama, Japan

Takehiro Tsutsumi