US3656986A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Chrome pigments
Assignee: Imperial Chemical Industries Ltd
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Filing: 1970-05-11
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Granted: 1972-04-18
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Expires: 1990-05-11
Abstract
Abstract Chrome pigments of improved durability, especially to atmospheric sulphurous acid, are obtained by adding to a stirred aqueous suspension of a chrome pigment at an initial pH between 1.8 and 8.0 a source of silicate ions, a source of trivalent antimony ions, and an organic hydroxy acid, and adjusting the pH to between 5 and 10.5 by addition of a water-soluble basic compound.
Inventors
- 👤 Charles Harold Buckley
- 👤 John Mitchell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:50
CPC Classifications
C; C09; C09C; C09C1/00; C09C1/14; C09C1/20; C01; C01P; C01P2006/00; C01P2006/90
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
24 words
A process as claimed in claim 1 wherein the pH is adjusted to between 5 and 9 by addition of a water-soluble basic compound.
Claim 2
Dependent Claim
29 words
A process as claimed in claim 1 wherein the amount of the source of silicate ions provides silica in amount between 2 and 5 percent of the chrome pigment.
Claim 3
Dependent Claim
20 words
A process as claimed in claim 1 wherein the silica provided is 3.5 percent of the weight of chrome pigment.
Claim 4
Dependent Claim
34 words
A process as claimed in claim 1 wherein the amount of the source of trivalent antimony ions provides antimony calculated as Sb2O3 in amount between 2 and 5 percent of the weight of pigment.
Claim 5
Dependent Claim
23 words
A process as claimed in claim 1 wherein the antimony calculated as Sb2O3 provided is 3 percent of the weight of chrome pigment.
Claim 6
Dependent Claim
25 words
A process as claimed in claim 1 wherein the amount of hydroxy acid is from 3 to 10 percent of the weight of chrome pigment.
Claim 7
Dependent Claim
16 words
A process as claimed in claim 1 wherein the hydroxy acid is an Alpha -hydroxy acid.
References Cited (Backward Citations)
US3434857A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-04-18 | 1975-10-18 | 1976-04-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-18 | 1979-10-18 | 1980-04-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-18 | 1983-10-18 | 1984-04-18 | $7700.00 | Window Closed / Lapsed |