Process for preparing an alpha or beta form copper phthalocyanine pigment

摘要

A process for preparing an alpha or beta form copper phthalocyanine pigment which comprises dry milling a crude copper phthalocyanine followed by mixing with an aqueous emulsion comprising a liquid amine having from 3 to 20 carbon atoms which is insoluble in water or alkali and soluble in acid and a surfactant which is capable of emulsifying the liquid amine and subsequently acidifying the mixture to dissolve the amine.