| 摘要 |
PURPOSE: To obtain an azo pigment, having a bright hue, finished in an extremely soft particle form and good in dispersibility in coating materials, etc., by heat-treating a crude azo pigment together with a specific compound. CONSTITUTION: (A) A crude azo pigment, together with (B) an aromatic compound having a water-soluble group [preferably in an amount of 10-300wt.% based on the component (A)], is heat-treated at >=80 deg.C temperature for a sufficient time to convert the crystal of the component (A) into a pigmentary form. The component (B) is then dissolved in water with (C) an alkaline aqueous solution to separate the resultant product. Furthermore, the component (A) is preferably an acetoacetanilide-based pigment or a naphthol-based pigment having a benzimidazolone group in the structure thereof and the component (B) is preferably a hydroxynaphthalene or its derivative, especiallyα-naphthol,β-naphthol, a halide, a sulfonated or a carboxylated substance of theα-naphthol orβ-naphthol or a mixture thereof.
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