| 摘要 |
The present invention relates to C. I. Pigment Red 254 for coloring, which can color an object to be colored so as to have a higher chroma than that with conventional technology and a production method for easily producing it. For the purpose, the inventors provide the production method for the pigment, wherein the intersection of mass tone DeltaH* and DeltaC* of a color coating film in an acrylic-melamine coating test is, on X-Y coordinate plane to which the DeltaH* is defined as the X-axis and the DeltaC* is defined as the Y-axis, within the surrounded region determined by specific three equations; and a production method for the pigment provides the production method of the pigment, including a process of heating crude pigment at 100-130 ° C. for 2-10 hours in an aprotic polar organic solvent which is strongly alkaline, which comprises the step of, prior to the heating process, beforehand, heating at 100-130 ° C. in neutral or weaker alkaline aprotic polar organic solvent, the mean particle diameter is finally larger than the mean particle diameter before heating.
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