Dainichiseika Color & Chemicals Mfg. Co., Ltd.

Yukio Kanbara

Kazuo Kanou

Keiji Nakajima

Masayuki Takahashi

Michiei Nakamura

Hiroyuki Shimanaka

Shotoku Takami

Shigeru Takarada

Kazutaka Aoki

Masahiko Aoba

Masayuki Kinnou

Chikamasa Nakamura

Takamitu Shinoda

A composite pigment of a bluish green color comprises copper phthalocyanine and aluminum phthalocyanine which are preferably in the form of a mixture or solid solution. The composite pigment can be produced by mixing copper phthalocyanine and aluminum phthalocyanine into a mixture and then converting said mixture into a pigment form. A coloring composition comprises at least a resin and a pigment which comprises copper phthalocyanine and aluminum phthalocyanine. The coloring composition can be produced by mixing copper phthalocyanine and aluminum phthalocyanine which have been independently comminuted, into a composite pigment, and then kneading the pigment and a resin such that the pigment is dispersed in the resin. An image recording substance is produced using the coloring composition. The image recording substance can be a dry developer of a fine powder form or a wet developer of a liquid form, an ink-jet ink, or a thermal transfer ink ribbon with the coloring composition coated on a film-shaped or sheet-shaped base material.

Composite pigments, coloring compositions, and image recording substances

A process is provided for producing a colored fine particulate composition by dissolving or dispersing a coloring matter or a coloring matter and charge control agent in a condensation-polymerized resin component and forming the resultant resin composition into fine particles. The coloring matter or the coloring matter and charge control agent are added to a raw material component for the production of the resin component, or to the resin component in a period from initiation to completion of polymerization of the resin component or while the resin component is in a molten state subsequent to the completion of the polymerization, whereby the coloring matter or the coloring matter and charge control agent are dissolved or dispersed in the resulting resin component. A colored composition obtained subsequent to the dissolution or the dispersion is cooled. The colored composition so cooled is then formed into fine particles.

Production process of colored fine particulate composition and colored fine particulate composition produced by the process

A pigment composition is composed of an intimate mixture of an organic pigment and a polymer. The content of the organic pigment is 75-95 wt. % based on the whole pigment composition. Monomers which form the polymer include 0-40 wt. % of styrene, 20-70 wt. % of a methacrylic ester and 20-50 wt. % of methacrylic acid. The total proportion of styrene, the methacrylic ester and methacrylic acid is at least 85 wt. % of the entire monomers. The pigment composition is prepared by mixing the organic pigment with an aqueous alkaline solution, which contains the polymer and an alkali metal salt, alkali metal hydroxide, lower amine or ammonium, to form an aqueous dispersion. The organic pigment and polymer are then subjected to coprecipitation, preferably, by lowering the pH of the aqueous dispersion beyond 7.0.

Pigment composition and preparation process thereof

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Tokyo, Japan

Yukio Kanbara