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 and 200.degree.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.