US3767455A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Treatment of oxide pigments
Assignee: Tronox Pigment UK Ltd
•
Filing: 1971-01-08
•
Granted: 1973-10-23
•
Expires: 1991-01-08
Abstract
Abstract Titanium dioxide pigment is coated with one or more substances selected from hydroxides, hydrous oxides, phosphates, and basic sulphates, and the coated pigment is subjected to hydrothermal pressure treatment by being maintained at a temperature of at least 50*C. in contact with liquid water, with a total ambient pressure of greater than one atmosphere.
Inventors
- 👤 M Claridge
- 👤 P Cowe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 14:49
CPC Classifications
C; C09; C09C; C09C1/00; C09C1/34; C09C1/346; C09C1/22; C09C1/24; C09C1/36; C09C1/3692; C09C3/00; C09C3/006; C09C3/04; C09C3/06; C09C3/063; C01; C01P; C01P2004/00; C01P2004/80; C01P2004/82; C01P2004/84; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/2993
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
32 words
A process according to claim 1, wherein an aqueous mixture including the coated pigment is sealed in a closed vessel and thereafter heated to the treatment temperature to produce a superatmospheric pressure.
Claim 2
Dependent Claim
24 words
A process according to claim 1, wherein the coated pigment is maintained at a temperature of at least 150*C. in said hydrothermal pressure treatment.
Claim 3
Dependent Claim
20 words
A process according to claim 1, wherein the duration of the said hydrothermal pressure treatment is at least 15 minutes.
Claim 4
Dependent Claim
20 words
A process according to claim 1, wherein the duration of the said hydrothermal pressure treatment does not exceed 2 hours.
Claim 5
Dependent Claim
37 words
A process according to claim 1, which includes the step of conveying the hydrothermally-treated pigment to apparatus for carrying out a further process step, the superatmospheric pressure in the treatment vessel being utilized in effecting said conveyance.
Claim 6
Dependent Claim
20 words
A process as claimed in claim 1 which comprises the step of milling said pigment after said hydrothermal pressure treatment.
Claim 7
Dependent Claim
22 words
A process according to claim 2, wherein a quantity of gas is introduced into the treatment vessel to augment the ambient pressure.
Claim 8
Dependent Claim
15 words
A process according to claim 4, wherein the said duration is at least 30 minutes.
Claim 9
Dependent Claim
33 words
A process according to claim 6, which includes the step of washing the coated pigment prior to the hydrothermal pressure treatment, and wherein the said further process step comprises spray drying the pigment.
Claim 10
Dependent Claim
34 words
An oxide pigment bearing a hydrothermally -pressure -treated coating comprising at least one substance selected from the group consisting of hydroxides, hydrous oxides, phosphates, and basic sulphates prepared by the process of claim 1.
References Cited (Backward Citations)
US2150235A
Cited
US3015573A
Cited
US3086877A
Cited
US3515566A
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US3382042A
Cited
US3468689A
Cited
US3488204A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-22 | 1977-04-23 | 1977-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-22 | 1981-04-23 | 1981-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-22 | 1985-04-23 | 1985-10-23 | $7700.00 | Window Closed / Lapsed |