| 摘要 |
This invention relates to a process for the preparation of quinacridone pigments by (a) heating, at a temperature of about 80.degree.C to about 145.degree.C, a reaction mixture containing (i) 2,5-dianilinoterephthalic acid, a 2,5-dianilino-6, 13-dihydroterephthalic acid ester, and/or a derivative thereof, (ii) about 3 to about 15 parts by weight, per part of component (a)(i), of a dehydrating agent, and (iii) about 0.1 to about 15 percent by weight, based on component (a)(i), of one or more non-quinacridone pigments, with the proviso that if component (a)(i) is a 2,5-dianilino-6, 13-dihydroterephthalic acid ester or a derivative thereof, reaction step (a) additionally comprises an oxidation step; (b) drowning the reaction mixture from step (a) by adding said reaction mixture to about 3 to about 15 parts by weight, per part of component (a)(i), of a liquid in which the quinacridone pigment is substantially insoluble; (c) isolating the quinacridone pigment; (d) optionally, conditioning the quinacridone pigment; and (e) optionally, blending the resultant pigment with one or more quinacridone derivatives.
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