Preparation of pigmentary form of quinacridone pigments
US4455173A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 16, 1982 |
| Grant date | Jun 19, 1984 |
| Priority date | — |
| Expiry date | Apr 16, 2002 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09B67/0022
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
Pigmentary grade quinacridone pigments are prepared from crude quinacridone by conversion to aggregated low crystallinity quinacridones followed by milling the aggregated low crystallinity quinacridone in the presence of a liquid which wets the pigment and can improve the crystallinity of quinacridone at 10.degree. to 60.degree. C. Suitable quinacridones include ##STR1## and mixtures thereof with up to 15 wt. % of ##STR2## where R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 R.sup.6 are hydrogen, fluorine, chlorine, bromine, methyl or methoxy; R.sup.7, R.sup.9 and R.sup.10 are hydrogen or chlorine; and R.sup.8 is hydrogen, chlorine, bromine, nitro, alkyl groups of 1 to 5 carbon atoms, alkoxy groups of 1 or 2 carbon atoms or benzoylamino, and m is an integer of from 1 to 4.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.