Process for the preparation of organic pigments
US5491235A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 6, 1994 |
| Grant date | Feb 13, 1996 |
| Priority date | — |
| Expiry date | May 6, 2014 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09B48/00
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
This invention relates to a process for the preparation of quinacridone pigments comprising PA1 (a) heating, at a temperature of about 80.degree. C. to about 145.degree. C., a reaction mixture comprising PA2 (i) 2,5-dianilinoterephthalic acid or a 2,5-dianilinoterephthalic acid derivative having one or more substituents in at least one aniline ring, PA2 (ii) about 2 to about 10 parts by weight, relative to component (i), of a strong acid, and PA2 (iii) at least about 0.4 mole percent, relative to component (i), of iron in the form of an iron salt; PA1 (b) drowning the reaction mixture from step (a) by adding said reaction mixture to about 3 to about 15 pads by weight, relative to component (i), of a liquid in which the pigment is substantially insoluble; PA1 (c) isolating the quinacridone pigment; and PA1 (d) optionally, conditioning the quinacridone pigment.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.