Process for preparing a substantially pure gamma phase quinacridone pigment of large particle size
US6402829B1 · kind B1 · utility
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10Claims
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Key dates
| Filing date | Dec 20, 2000 |
| Grant date | Jun 11, 2002 |
| Priority date | — |
| Expiry date | Dec 20, 2020 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09B67/0027
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
An improved process for producing a substantially pure gamma phase a quinacridone pigment or pigment derivative involving preparing an aqueous slurry of a crude quinacridone in the presence of caustic alkali and a non-polar, water immiscible solvent; and heating said slurry at a temperature above about 120° C.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.