US4082905A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of iron oxide pigments with improved resistance to oxidation
Assignee: Bayer AG
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Filing: 1977-05-16
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Granted: 1978-04-04
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Expires: 1997-05-16
Abstract
Abstract An Fe 3 O 4 iron oxide black pigment having incorporated therein up to about 50 mole percent of γ-Fe 2 O 3 plus Me Fe 2 O 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 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° 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.
Inventors
- 👤 Bernd Stephan
- 👤 Franz Hund
- 👤 Wilhelm Holznagel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:25
CPC Classifications
C; C09; C09C; C09C1/00; C09C1/22; C09C1/24; G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70626; G11B5/70642; G11B5/70647; G11B5/70678; G11B5/70684; C01; C01P; C01P2004/00; C01P2004/80; C01P2004/82; C01P2004/84; C01P2006/00; C01P2006/32; C01P2006/37
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
91 words
An Fe 3 O 4 iron oxide black pigment having incorporated therein up to about 50 mole percent of γ-Fe 2 O 3 plus MeFe 2 O 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 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° C.
Claim 2
Dependent Claim
91 words
An Fe 3 O 4 iron oxide black pigment having incorporated therein up to about 50 mole percent of γ-Fe 2 O 3 plus MeFe 2 O 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 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° C.
Claim 3
Dependent Claim
25 words
A pigment as claimed in claim 1, wherein the coating comprises at leasst one of zinc hydroxide, zinc phosphate, zinc phosphite, aluminum phosphate and silica.
Claim 4
Dependent Claim
30 words
A pigment as claimed in claim 2, having a stability to oxidation with air greater than about 190° C, the coating being present in about 0.2 to 5% by weight.
Claim 5
Dependent Claim
30 words
A pigment as claimed in claim 2, having a stability to oxidation with air greater than about 210° C, the coating being present in about 0.2 to 5% by weight.
Claim 6
Dependent Claim
119 words
A process for the aftertreatment of an Fe 3 O 4 iron oxide black pigment having incorporated therein up to about 50 mole percent of γ-Fe 2 O 3 plus Me Fe 2 O 4 (wherein Me is at least one of magnesium, manganese, cobalt, nickel, aluminum, chromium, titanium, copper, zinc and cadmium) which comprises forming an aqueous suspension of the pigment, dissolving an inorganic compound in the suspension, adding to the suspension a material which reacts with the inorganic compound to form an insoluble inorganic compound which precipitates onto said pigment as a coating in a quantity of from about 0.1 to 10% by weight and removing the pigment provided with the precipitated coating from the aqueous phase.
Claim 7
Dependent Claim
119 words
A process for the aftertreatment of an Fe 3 O 4 iron oxide black pigment having incorporated therein up to about 50 mole percent of γ-Fe 2 O 3 plus Me Fe 2 O 4 (wherein Me is at least one of magnesium, manganese, cobalt, nickel, aluminum, chromium, titanium, copper, zinc and cadmium) which comprises forming an aqueous suspension of the pigment, dissolving an inorganic compound in the suspension, adding to the suspension a material which reacts with the inorganic compound to form an insoluble inorganic compound which precipitates onto said pigment as a coating in a quantity of from about 0.1 to 10% by weight and removing the pigment provided with the precipitated coating from the aqueous phase.
Claim 8
Dependent Claim
56 words
A process as claimed in claim 5, wherein the soluble inorganic compound is a compound of at least one of zinc, aluminum or silica and the material added to the suspension forms at least one of zinc hydroxide, zinc phosphate, zinc phosphite, aluminum phosphate and silica in about 0.2 to 5% by weight of the pigment.
Claim 9
Dependent Claim
11 words
An inorganic dispersion pigmented with a pigment according to claim 1.
Claim 10
Dependent Claim
11 words
An organic dispersion pigmented with a pigment according to claim 1.
Claim 11
Dependent Claim
10 words
A magnetogram support carrying a pigment according to claim 1.
References Cited (Backward Citations)
US3873461A
Cited
US3931025A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-04-03 | 1981-10-03 | 1982-04-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-04-03 | 1985-10-03 | 1986-04-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-04-03 | 1989-10-03 | 1990-04-04 | $7700.00 | Window Closed / Lapsed |