PIGMENT COMPOSITION AND METHOD FOR PRODUCING THE SAME

PROBLEM TO BE SOLVED: To provide C.I. Pigment Red 185 displaying specific red color by β-type crystal structure and forming a colored product having excellent fluidity when mixed with a resin or the like, and to provide a simple method for producing the pigment. SOLUTION: The pigment composition comprises a surfactant and the C.I. Pigment Red 185 having 1.0-2.5 average aspect ratio and the β-type crystal structure, and the method comprises simultaneously dropping a diazonium salt water solution or a water dispersion of 1-amino-2-methoxy-5-methylbenzene-4-sulfonic acid methylamide and a water solution or a water dispersion of 5-(2'-oxy-3'-naphthoyl-amino)-benzimidazolone into water containing a surfactant and a pH buffer, wherein the pH buffer concentration is adjusted to be 0.1-2.0%, so as to perform coupling reaction and then the obtained is made into the pigment in an aqueous medium. COPYRIGHT: (C)2004,JPO