Process for the production of β type copper phthalocyanine pigment and a use thereof

A process for the production of a β type copper phthalocyanine pigment having an average primary crystal diameter of 80±40 nm and a primary crystal aspect ratio of 2.0±1.0 and having a crystallite diameter of 22±5 nm in the direction perpendicular to a monoclinic β (200) plane, a crystallite diameter of 27±5 nm in the direction perpendicular to a β (001) plane and a crystallite diameter of 15±5 nm in the direction perpendicular to a β (010) plane,

• which process comprises,
• the step (A) of dry-milling a crude copper phthalocyanine having a purity, based on a sulfuric acid dissolution method, of 97 to 100% and a primary crystal diameter of 0.5 to 100 μm at a temperature of 180 to 50° C., to prepare an α/β mixed crystal type copper phthalocyanine having an α ratio of 5 to 35%, and
• the step (B) of treating a dry-milled product obtained in the step (A) with a water-miscible organic solvent,
• wherein 0.1 to 20% by weight of at least one compound selected from the group consisting of a compound of the formula (1), a compound of the formula (2) and a compound of the formula (3) is added to the dry-milled product before, during or after the step (B),
• MePc—{X—(CH2)kNR1R2}n (1)
• in which Me represents H2, Cu, Fe, Co, Ni, Zn, AlOH or FeOH, Pc represents a phthalocyanine residue, X represents CH2, CH2NHCOCH2, CO, SO2, CH2NH, CH2NHCOCH2NH, CONH or SO2NH, k is an integer of 0 to 6, R1 and R2 are each independently a hydrogen atom or an substituted or non-substituted alkyl or alkenyl group having 1 to 18 carbon atoms or R1 and R2 together form a five-membered or six-membered ring which may further contain a nitrogen atom, and n is an integer of 1 to 4,
• in which Me and Pc have the same meanings as those in the formula (1), Y is a halogen atom, an alkyl group, a nitro group, an amino group, a sulfone group or a carboxylic group, q is an integer of 1 to 3 and m is an integer of 0 to 4,
• MePc—(SO3−N+R5R6R7R8)p (3)
• in which Me and Pc have the same meanings as those in the formula (1), R5, R6, R7 and R8 are each independently a hydrogen atom, a substituted or non-substituted alkyl or alkenyl group having 1 to 30 carbon atoms or a polyoxy lower alkyl or alkenyl group, provided that at least one of R5, R6, R7 and R8 is an alkyl or alkenyl group having at least 10 carbon atoms or a polyoxy lower alkyl or alkenyl group, and p is an integer of 1 to 8.