Sumitomo Chemical Company, Limited

Hideki Senba

Yoshiaki Hayashi

Hiroki Inoue

Keisuke Ito

Makoto Akita

A composition used for an ingredient of printing ink, which comprises an organic pigment and a pigment derivative represented by the formula (I) in the acid form: ##STR1## wherein D represents a residue of an organic pigment other than azo, R.sub.1 represents a hydrogen atom or an unsaturated aliphatic, saturated aliphatic or aromatic hydrocarbon group having 1 to 20 carbon atoms, R.sub.2 represents an unsaturated aliphatic, saturated aliphatic or aromatic hydrocarbon group having 1 to 20 carbon atoms, m represents a number of from 0 to 3 and n represents a number of from 1 to 4, provided that m+n is from 1 to 5.

Composition for printing inks

A pigment composition which comprises an organic pigment and a dioxazine pigment derivative represented by the following formula (I); ##STR1## wherein R.sub.1 and R.sub.2 each independently represents a substituted or unsubstituted and saturated or unsaturated aliphatic hydrocarbon group or aromatic hydrocarbon group, or R.sub.1 and R.sub.2 form a heterocyclic ring; L is an integer of 1-6; m is 0.5-3; and n is 0.5-3.5 provided that total of m and n is 1-5 or a salt thereof; and the pigment composition can be used with excellent pigment characteristics for various uses, and particularly, when they are used for paints or printing inks in the form of non-aqueous dispersion system, the dispersion system has lower dispersion viscosity and exhibits good flowability and there occurs no color segregation in the dispersion system and it has high coloring power and gives good prints or coats having good gloss and high transparency.

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Osaka, Japan

Hideki Senba