To provide a method for producing an organic pigment composition in which organic pigment particulates are contained and the hydrophilicity or hydrophobicity of the particulates or secondary particles (aggregates) thereof can be simply switched without passing through a complicated process, and to provide an organic pigment composition obtained by the method.
There is provided a method for producing an organic pigment composition containing a crosslinked polymer compound obtained by crosslinking a crosslinkable polymer through a linking group and having a number average molecular weight of 1,000 or more and the organic pigment particulates. The method includes mixing a solution obtained by dissolving the crosslinked polymer compound and an organic pigment in a good solvent and a medium which is compatible with the good solvent and is a poor solvent to the organic pigment to form the organic pigment particulates in the mixed solution.
KATAYAMA AKIO
Wataru Sasaki
Naosuke Miyamae