Process for producing 4,4'-Diamino-1,1'-dianthraquinonyl pigments
US5416263A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 10, 1993 |
| Grant date | May 16, 1995 |
| Priority date | — |
| Expiry date | May 10, 2013 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09B1/005
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
4,4'-Diamino-1,1'-dianthraquinonyl compounds which are obtained in a known manner and which are easy to agglomerate or aggregate owing mainly to their too fine particle size are conditioned by heating an aqueous suspension consisting essentially of the 4,4'-diamino-1,1'-dianthraquinonyl compound and water in the presence or absence of a mineral acid or an alkali. The thus obtained 4,4'-diamino-1,1'-dianthraquinonyl pigments are used in paints, printing inks, coloring of plastics and the like. The aqueous suspension is preferably prepared by desulfonating a 4,4'-diamino-1,1'-dianthraquinonyl-3,3'-disulfonic acid compound in a mineral acid such as sulfuric acid and then mixing the desulfonation reaction mixture with water or by once isolating the resulting 4,4'-diamino-1,1'-dianthraquinonyl compound and mixing the isolated compound with water.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.