Incorporation of pigment derivatives in quinacridone processes
US5713999A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 29, 1996 |
| Grant date | Feb 3, 1998 |
| Priority date | — |
| Expiry date | Apr 29, 2016 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09B67/0036
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
This invention relates to a process for the preparation of quinacridone pigments by PA1 (a) heating, at a temperature of about 80.degree. C. to about 145.degree. C., a reaction mixture containing PA2 (i) 2,5-dianilinoterephthalic acid, a 2,5-dianilino-3,6-dihydroterephthalic acid ester, and/or a derivative thereof, PA2 (ii) about 3 to about 15 parts by weight, per part of component (a)(i), of a dehydrating agent, and PA2 (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-3,6-dihydroterephthalic acid ester or a derivative thereof, reaction step (a) additionally comprises an oxidation step; PA1 (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; PA1 (c) isolating the quinacridone pigment; PA1 (d) optionally, conditioning the quinacridone pigment; and PA1 (e) optionally, blending the resultant pigment with one or more quinacridone derivatives.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.