Process for producing beta -form copper phthalocyanine pigment

摘要

The present invention is a method for preparing a beta -form copper phthalocyanine pigment comprising the steps of; dry milling crude copper phthalocyanine at a temperature between 110 DEG and 200 DEG C., and transforming an alpha -form crystal to a beta -form crystal by treating the resulting alpha - beta mixture of copper phthalocyanine in an organic solvent or a liquid mixture of water and an organic solvent. The preparation method of the present invention offers a beta -form copper phthalocyanine pigment at lower cost having equivalent or superior quality in color strength, clearness, fluidity and hue compared to the pigment produced by the conventional salt milling method.