Method for producing quinacridone solid-solution pigment, pigment dispersion, and ink-jet ink

Abstract

A quinacridone solid solution pigment that allows a colored product to have high chroma and a properly yellowish hue and has a controlled particle diameter, and a method for producing the quinacridone solid solution pigment. In the method, a water-containing crude quinacridone solid solution is produced by a co-cyclization reaction of a diarylaminoterepththalic acid and a dialkylarylaminoterephthalic acid in polyphosphoric acid, then the resulting water-containing crude quinacridone solid solution having a mass ratio of unsubstituted quinacridone to a 2,9-dialkylquinacridone of 85:15 to 60:40 is dried, thereby obtaining a powdery, crude quinacridone solid solution having a water content of less than 1%. Then, the resulting powdery, crude quinacridone solid solution is heated in a liquid medium that does not dissolve the crude quinacridone solid solution. Also, a pigment dispersion liquid and an inkjet ink each containing the obtained quinacridone solid solution pigment are provided.

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