| 摘要 |
<p>PURPOSE:To produce the subject composition forming a thick-printed part having a large hue and a deep color, excellent in transparency and gloss and useful, e.g. as a pigment for printing ink see, by adding humic acid, etc., to a reaction solution before synthesis of a red azo pigment and treating the pigment therewith. CONSTITUTION:The objective composition is produced by adding preferably 0.1-5wt.% (based on red azo pigment) humic acid or salt thereof to a reaction solution before synthesis of a red azo pigment obtained, e.g. by coupling a diazo compound such as 2-chloro-4-aminotoluene-5-sulfonic acid with beta-naphthol, etc., or to a dye or pigment slurry after synthesis and treating the pigment therewith.</p> |
