There is provided a technique for producing a quinacridone solid solution pigment, the technique making it possible to obtain a quinacridone solid solution pigment which produces a colored product having high chroma and a bluish hue, more preferably which has controlled particle diameters. Specifically, a method for producing a quinacridone solid solution pigment, the method including a crude quinacridone solid solution production step of subjecting a diarylaminoterepththalic acid and a dialkylarylaminoterephthalic acid to a co-cyclization reaction in polyphosphoric acid, thereby obtaining a water-containing crude quinacridone solid solution containing a solid solution of an unsubstituted quinacridone and a 2,9-dialkylquinacridone, the solid solution containing water, a drying step of drying the water-containing crude quinacridone solid solution to reduce the water content to less than 1% and obtain a powdery, crude quinacridone solid solution, and a pigmentation step of heating the powdery, crude quinacridone solid solution in a liquid medium that cannot dissolve the crude quinacridone solid solution.

There is provided a technique for producing a quinacridone solid solution pigment, the technique making it possible to obtain a quinacridone solid solution pigment which produces a colored product having high chroma and a bluish hue, more preferably which has controlled particle diameters. Specifically, a method for producing a quinacridone solid solution pigment, the method including a crude quinacridone solid solution production step of subjecting a diarylaminoterepththalic acid and a dialkylarylaminoterephthalic acid to a co-cyclization reaction in polyphosphoric acid, thereby obtaining a water-containing crude quinacridone solid solution containing a solid solution of an unsubstituted quinacridone and a 2,9-dialkylquinacridone, the solid solution containing water, a drying step of drying the water-containing crude quinacridone solid solution to reduce the water content to less than 1% and obtain a powdery, crude quinacridone solid solution, and a pigmentation step of heating the powdery, crude quinacridone solid solution in a liquid medium that cannot dissolve the crude quinacridone solid solution.

There is provided a technique for producing a quinacridone solid solution pigment, the technique making it possible to obtain a quinacridone solid solution pigment which produces a colored product having high chroma and a bluish hue, more preferably which has controlled particle diameters. Specifically, a method for producing a quinacridone solid solution pigment, the method including a crude quinacridone solid solution production step of subjecting a diarylaminoterepththalic acid and a dialkylarylaminoterephthalic acid to a co-cyclization reaction in polyphosphoric acid, thereby obtaining a water-containing crude quinacridone solid solution containing a solid solution of an unsubstituted quinacridone and a 2,9-dialkylquinacridone, the solid solution containing water, a drying step of drying the water-containing crude quinacridone solid solution to reduce the water content to less than 1% and obtain a powdery, crude quinacridone solid solution, and a pigmentation step of heating the powdery, crude quinacridone solid solution in a liquid medium that cannot dissolve the crude quinacridone solid solution.

An object to be achieved by the present, invention is to provide a quinacridone pigment having hue that is yellowish and clear and having excellent storage stability, wherein the quinacridone pigment can be advantageously used in an ink-jet ink and the like. Provided is a quinacridone solid solution pigment comprising at least C. I. Pigment Violet 19 and C. I. Pigment Red 122, wherein the ratio of a diffraction peak intensity at a diffraction angle 2 of 14.80.2 to a diffraction peak intensity at a diffraction angle 2 of 11.90.2 is 1.20 or less, as measured by X-ray diffractometry with respect to the quinacridone solid solution pigment.

The present invention relates to a technique for providing a quinacridone solid solution pigment, by which a quinacridone solid solution pigment that allows a colored product to have high chroma and a properly yellowish hue, and suitably, that has a controlled particle diameter and has the above-described, desired hue can be obtained. The present invention provides a method for producing a quinacridone solid solution pigment, wherein a diarylaminoterepththalic acid and a dialkylarylaminoterephthalic acid are subjected to a co-cyclization reaction in polyphosphoric acid, thereby obtaining a water-containing crude quinacridone solid solution such that water is contained in a solid solution having a mass ratio of unsubstituted quinacridone to a 2,9-dialkylquinacridone of 85:15 to 60:40; the water-containing crude quinacridone solid solution obtained above is dried in a drying step, thereby obtaining a powdery, crude quinacridone solid solution having a water content of less than 1%; and the powdery, crude quinacridone solid solution is heated in a liquid medium that does not dissolve the crude quinacridone solid solution in a pigmentation step, and the present invention also provides a pigment dispersion liquid and an inkjet ink each containing the obtained quinacridone solid solution pigment.

There is provided a technique for producing a quinacridone solid solution pigment, the technique making it possible to obtain a quinacridone solid solution pigment which produces a colored product having high chroma and a bluish hue, more preferably which has controlled particle diameters. Specifically, a method for producing a quinacridone solid solution pigment, the method including a crude quinacridone solid solution production step of subjecting a diarylaminoterepththalic acid and a dialkylarylaminoterephthalic acid to a co-cyclization reaction in polyphosphoric acid, thereby obtaining a water-containing crude quinacridone solid solution containing a solid solution of an unsubstituted quinacridone and a 2,9-dialkylquinacridone, the solid solution containing water, a drying step of drying the water-containing crude quinacridone solid solution to reduce the water content to less than 1% and obtain a powdery, crude quinacridone solid solution, and a pigmentation step of heating the powdery, crude quinacridone solid solution in a liquid medium that cannot dissolve the crude quinacridone solid solution.

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.