Preparation of α- β- and γ-copper phthalocyanine pigments

Claim 1

In a process for the production of alpha-copper phthalocyanine pigments which comprises reacting an orthodinitrilo compound of the general formula ##STR8## in which A forms an aryl or aromatic heterocyclic radical, X is a hydrogen or halogen atom or a nitro, amino, sulphonic acid, carboxylic acid, alkyl or alkoxy group and n is an integer from 1 to 4; and copper or a copper compound capable of providing the central metal atom of a phthalocyanine pigment at a temperature below 100° C. in the presence of an alkaline substance which is a hydroxide, oxide, peroxide, alkoxide or carbonate of an alkali metal or of an alkaline earth metal in a hydrophilic aliphatic organic solvent containing one or more hyroxy groups wherein the improvement whereby high quality pigments are obtained without need for acid-pasting or mechanical pulverization comprises adding as crystal form controller from the beginning of the reaction (a) 0.5% to 40% of an alpha-phase copper phthalocyanine pigment by weight based on the weight of pigment synthesized, or (b) 0.5% to 10% of a copper phthalocyanine derivative selected from the group consisting of chlorinated copper phthalocyanine, copper phthalocyanine sulfonic acid, 1,2,4-trichloro-3-phenoxy copper phthalocyanine or ##STR9##