Pigmentary synthesis of quinacridone solid solutions
US5457203A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 15, 1993 |
| Grant date | Oct 10, 1995 |
| Priority date | — |
| Expiry date | Sep 15, 2013 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09B48/00
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A general method for the direct preparation of pigmentary quinacridone solid solutions is disclosed. The disclosed process comprises oxidizing a mixture of dihydroquinacridones directly to a pigmentary quinacridone solid solution wherein the oxidation is carried out by heating a reaction mixture comprising the dihydroquinacridone mixture, an alkali metal hydroxide, a water miscible organic solvent, water and effective mounts of an oxidizing agent and a particle growth inhibitor. In addition, an analogous process useful for the direct pigmentary synthesis of .alpha.-quinacridone is disclosed. The pigments prepared by the disclosed processes do not require additional particle-size reducing after treatments in order to be useful as pigments.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.