Production of iron oxide pigments with improved resistance to oxidation
US4082905A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 16, 1977 |
| Grant date | Apr 4, 1978 |
| Priority date | — |
| Expiry date | May 16, 1997 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01P2006/37
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An Fe.sub.3 O.sub.4 iron oxide black pigment having incorporated therein up to about 50 mole percent of .gamma.-Fe.sub.2 O.sub.3 plus Me Fe.sub.2 O.sub.4 (wherein Me is at least one of magnesium, manganese, cobalt, nickel, aluminum, chromium, titanium, copper, zinc and cadmium) having a specific surface according to BET of greater than about 12 m.sup.2 /g, up to about 10% by weight of a substantially insoluble inorganic compound as coating and a stability to oxidation with air under standardized conditions of greater than about 130.degree. C. Advantageously the coating comprises at least one of zinc hydroxide, zinc phosphate, zinc phosphite, aluminum phosphate and silica, being precipitated onto the suspended pigment from a solution. The resulting pigments are of improved resistance to oxidation, rendering them especially useful for pigmenting inorganic and organic dispersions and for use on magnetogram supports.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.