US3640744A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Titanium dioxide of improved chalk resistance
Assignee: PPG Industries Inc
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Filing: 1969-02-28
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Granted: 1972-02-08
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Expires: 1989-02-28
Abstract
Abstract Pigmentary titanium dioxide, especially titanium dioxide containing coreacted aluminum and silicon, is heat treated and then given a hydrous metal oxide coating, e.g., an alumina and silica coating. The resulting pigment has good chalk resistance and good retention of optical properties, such as gloss, color and tint efficiency.
Inventors
- 👤 Albert Dietz
- 👤 Neil C Goodspeed
- 👤 Russell R May Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:22
CPC Classifications
C; C09; C09C; C09C1/00; C09C1/36; C09C1/3692; C09C3/00; C09C3/06; C09C3/063; C09C3/08; C09C3/12; C01; C01P; C01P2004/00; C01P2004/80; C01P2004/82; C01P2004/84
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
82 words
In the method of treating raw pigmentary titanium dioxide containing from about 1 to about 2.5 weight percent cooxidized alumina and from about 0.3 to about 0.75 weight percent cooxidized silica by coating said pigment with hydrous alumina and hydrous silica, the improvement which comprises increasing the photolytic stability of said pigment by heating said raw pigment at from about 600* to about 650* C. for from about 20 to about 30 minutes before coating said pigment with said hydrous metal oxide.
Claim 2
Dependent Claim
28 words
A method according to claim 2 wherein the total amount of hydrous metal oxide coating ranges from about 2 to about 20 weight percent, based on titanium dioxide.
Claim 3
Dependent Claim
28 words
A method according to claim 1 wherein said raw pigment is heated at from about 600* to about 650* C. for from about 20 to about 30 minutes.
Claim 4
Dependent Claim
28 words
A method according to claim 1 wherein the total amount of hydrous metal oxide coating ranges from about 2 to about 20 weight percent, based on titanium dioxide.
Claim 5
Dependent Claim
9 words
Pigmentary titanium dioxide prepared by the method of claim
Claim 6
Dependent Claim
10 words
Pigmentary titanium dioxide prepared by the method of claim 2.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-02-07 | 1975-08-09 | 1976-02-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-07 | 1979-08-09 | 1980-02-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-07 | 1983-08-09 | 1984-02-08 | $7700.00 | Window Closed / Lapsed |