| 摘要 |
PROBLEM TO BE SOLVED: To produce aβ-form copper phthalocyanine pigment having excellent pigment dispersibility by wet-grinding a reaction mixture containing an organic solvent solution of crude copper phthalocyanine produced in an organic solvent and removing the organic solvent from the obtained suspension. SOLUTION: A solvent (e.g. alkylbenzene) is mixed with a mixture comprising phthalic anhydride and an aromatic polybasic acid (e.g. trimellitic anhydride) represented by the formula (wherein R<1> to R<4> are each H, carboxyl or the like; and A and B are each carboxyl, carbamoyl or the like) in a molar ratio of 90/10 to 99.7/0.3, and about 0.8-1.3mol, per 4mol of phthalic anhydride, of a copper compound (e.g. CuCl), about 4-26mol of urea or the like and about 0.01-0.04 equivalent of a catalyst (e.g. ammonium molybdate) are added to the above mixture. The resulting mixture is reacted by heating to about 180 deg.C under agitation, the formed reaction mixture is cooled and dispersed to prepare a crude copper phthalocyanine solution having a concentration of about 10-30%. After the dispersion is wet-ground with, e.g. a ball mill, and the solvent is removed from the obtained dispersion by steam distillation, and the precipitate is filtered, washed with water and dried to obtain aβ-form copper phthalocyanine pigment.
|
