Toyo Ink Manufacturing Company

Toyo Ink Mfg. Co., Ltd.

Takahiro Yuasa

Ataru Chiba

Ippei Imagawa

Kenzi Kitamura

A pigment composition obtainable by dry-milling an organic pigment in the presence of a resin for a printing ink, the resin being composed of a synthetic resin for a printing ink in an amount of 10 to 80 parts by weight per 100 parts by weight of the organic pigment and an aliphatic hydrocarbon resin which is extracted from gilsonite and has a softening point of 120 to 125&#xb0; C. in an amount of 0.1 to 5 parts by weight per 100 parts by weight of the organic pigment.

Pigment composition and printing ink containing the same

An azo pigment composition which forms a dispersion having high tinting strength and excellent clearness, transparency, fluidity and storage stability, and which is formed from a coupling reaction between a diazo component and a coupler component, and contains a compound represented by formula (I) ##STR1## wherein Q represents a diazo or coupler component moiety, A represents a divalent bonding group selected from a class consisting of --CONR'--, SO.sub.2 NR'--, --CH.sub.2 NH-- and --CH.sub.2 NHCOCH.sub.2 NH-- in which R' represents a hydrogen atom, alkyl group having 1 to 20 carbon atoms or aryl group,

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Tokyo, Japan

Takahiro Yuasa