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AssigneeDIC Corporation
InventorsYoshiharu Ootoshi, Masayoshi Takahashi, Yuuichi Ayuta
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The present invention provides a method for producing a pigment composition for a printing ink, which involves the step of dry-milling crude copper phthalocyanine using calcium carbonate having a specific property; a pigment composition for a printing ink; and a method for producing a printing ink using the pigment composition. Specifically, the present invention provides a method for producing a pigment composition for a printing ink, which involves the step of dry-milling crude copper phthalocyanine and calcium carbonate having a primary particle diameter of 20 to 1500 nm in the absence of a resin for a printing ink; a pigment composition produced by the method; and a method for producing a printing ink, which includes the steps of heating a mixture of a pigment composition, a resin for a printing ink and a solvent for the printing ink, and wet-milling the heated mixture.
A pigment composition for a printing ink, comprising an aggregate of copper phthalocyanine particles, characterized in that (1) the copper phthalocyanine particles include two or more kinds of crystal forms, (2) the aggregate contains the calcium carbonate particles therein, and (3) a resin for a printing ink does not substantially exist in the aggregate,
Dependencies are inferred from the claim text.