MANUFACTURE OF COLORING AGENT

PURPOSE:To easily obtain a coloring agent which is excellent in pigment dispersion and of which the maximum particle diameter of coarse pigment particles can readily be reduced to 30mum or smaller when used for coloring, e.g., thermoplastic resin, with improved productivity without the necessity for subsequent heating and kneading with three rolls, etc., hitherto required. CONSTITUTION:Manufacture of a coloring agent, in which a pigment, for example, wet cake of phthalocyanine pigment or powder carbon black and a wax dispersion prepared by dispersing a wax, for example, polyethylene wax in a dispersion medium comprising, e.g., water or a hydorphilic solvent are heated and kneaded to effect phase substitution (flushing), separated liquid material such as a dispersion medium is removed, and preferably further heating and kneading is performed while removing remaining liquid material; and manufacture of a coloring agent, in which the obtained coloring agent and a thermoplastic resin are heated and kneaded.