Preparation of .gamma.-quinacridone pigment
US4197404A · kind A · utility
13Cited by
3References
4Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | May 8, 1978 |
| Grant date | Apr 8, 1980 |
| Priority date | — |
| Expiry date | May 8, 1998 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09B48/00
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
In a process for preparing pigmentary .gamma.-quinacridone by oxidizing .beta.-dihydroquinacridone with a mild alkali-stable oxidizing agent in a liquid medium consisting of alkali metal hydroxide, water and a polar, alkali-stable, water-soluble organic liquid, this invention provides for an improvement wherein the oxidation is conducted in the presence of 0.1% to 1% by weight of an o-carboxybenzamidomethyl quinacridone compound whereby the resulting .gamma.-quinacridone exhibits sufficiently high strength so that milling or solvent treatments to increase pigment strength are unnecessary.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.