Process for producing dichlorodiketopyrrolopyrrole pigment of the alpha modification, dichlorodiketopyrrolopyrrole pigment of the alpha modification produced by the process, and coloring composition using the same

摘要

A process for producing dichlorodiketopyrrolopyrrole pigment of the α modification, which comprises wet milling crude dichlorodiketopyrrolopyrrole pigment wherein an α modification and a β modification coexist in the presence of a milling agent and a wetting agent, dichlorodiketopyrrolopyrrole pigment of the α modification obtained the process and a color composition which contains the pigment and a pigment carrier.