Patent US4161409A successfully refreshed from Google Patents.
US4161409A
Expired / Lapsed
US
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Corrosion inhibitive pigment
Assignee: Individual
•
Filing: 1978-03-06
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Granted: 1979-07-17
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Expires: 1998-03-06
Abstract
Abstract A chromium chromate complex, obtained by partial reduction of chromic acid in aqueous media with an organic reducing agent, is converted to pigment form by evaporating the resulting aqueous composition to dryness and sub-dividing the obtained solid mass to suitable size. The obtained pigment, with or without intimately associated extenders, incorporated in a conventional vehicle, serves as a corrosion inhibitor in metal coating compositions.
Inventors
- 👤 Louis Schiffman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:53
CPC Classifications
C; C09; C09D; C09D5/00; C09D5/08; C09D5/082; C09D5/084; C09C; C09C1/00; C09C1/34; C09C1/346; C01; C01P; C01P2004/00; C01P2004/60; C01P2004/61
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
78 words
The method of preparing a corrosion-inhibiting pigment which comprises reacting a hexavalent chromium compound in aqueous solution with a water soluble oxidizable organic compound containing an active hydroxyl, aldehyde or carbonyl group at a temperature below 95° C. and under conditions to reduce 5 to 70% of the hexavalent chromium compound to lower valent state, evaporating the resulting aqueous reaction product to dryness at a temperature below 150° C., and pulverizing the dried product to pigment size range.
Claim 2
Independent Claim
78 words
The method of preparing a corrosion-inhibiting pigment which comprises reacting a hexavalent chromium compound in aqueous solution with a water soluble oxidizable organic compound containing an active hydroxyl, aldehyde or carbonyl group at a temperature below 95° C. and under conditions to reduce 5 to 70% of the hexavalent chromium compound to lower valent state, evaporating the resulting aqueous reaction product to dryness at a temperature below 150° C., and pulverizing the dried product to pigment size range.
Claim 3
Dependent Claim
32 words
The method as defined in claim 1 wherein a 20-50% solution of chromic acid is employed and reacted with methanol wherein the mols of methanol to chromic acid is less than 1:1.
Claim 4
Dependent Claim
14 words
The method as defined in claim 1 wherein the oxidizable organic compound is formaldehyde.
Claim 5
Dependent Claim
14 words
The method as defined in claim 1 wherein the oxidizable organic compound is furfural.
Claim 6
Dependent Claim
22 words
The method as defined in claim 1 wherein 25 to 65% of the hexavalent chromium compound is reduced to lower valent state.
Claim 7
Dependent Claim
40 words
Corrosion inhibiting composition comprising a chromium chromate pigment wherein said chromium chromate contains 95 to 30% of the total chromium therein in hexavalent state, said pigment being essentially free of corrosive anions and also substantially free of extraneous heavy metals.
Claim 8
Dependent Claim
40 words
Corrosion inhibiting composition comprising a chromium chromate pigment wherein said chromium chromate contains 95 to 30% of the total chromium therein in hexavalent state, said pigment being essentially free of corrosive anions and also substantially free of extraneous heavy metals.
Claim 9
Dependent Claim
17 words
Corrosion-inhibiting composition as defined in claim 6 wherein said pigment is dispersed in a film-forming organic vehicle.
Claim 10
Dependent Claim
13 words
Composition as defined in claim 7 wherein said vehicle comprises a drying oil.
Claim 11
Dependent Claim
16 words
Composition as defined in claim 7 wherein said vehicle comprises at least one synthetic resin base.
Claim 12
Dependent Claim
20 words
Composition as defined in claim 7 wherein said vehicle comprises a water emulsion of at least one synthetic resin base.
Claim 13
Dependent Claim
14 words
Composition as defined in claim 10 wherein said vehicle comprises an acrylate emulsion system.
Claim 14
Dependent Claim
20 words
Composition as defined in claim 6 wherein said chromium chromate is intimately associated with finely divided insoluble inorganic extender material.
Claim 15
Dependent Claim
13 words
Composition as defined in claim 12 wherein said extender material comprises magnesium silicate.
Claim 16
Dependent Claim
14 words
Composition as defined in claim 12 wherein said extender material comprises finely divided talc.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-07-16 | 1983-01-15 | 1983-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-07-16 | 1987-01-15 | 1987-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-07-16 | 1991-01-15 | 1991-07-17 | $7700.00 | Window Closed / Lapsed |