| 摘要 |
PURPOSE:An organic pigment is dissolved in a solvent together with a nonionic surfactant in the presence of a caustic alkali and water, precipitated by neutralization with an acid, combined with heteropolyacid, whereby the finely crushing of the coarse pigment, the purification of the pigment and the contact treatment between the primary particles and the surfactant are effected simultaneously through one-step operation. CONSTITUTION:An organic pigment, preferably quinacridone, azo or thioindigo, together with a nonionic surfactant, preferably of 15-20HLB, are dissolved in an aprotic polar solvent such as dimethylslufoxide, dimethylimidazolidinone, or N-methyl-2-pyrrolidone in the presence of a caustic alkali, preferably KOH, NaOH and water. Then, the pigment is precipitated by neutralizing the solution with an acid such as sulfuric acid or organic acid, then, heterpoly acid such as phosphotungstenic acid or tannic acid is added to the precipitate.
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