Patent US2628919A successfully refreshed from Google Patents.
US2628919A
Expired / Lapsed
US
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Production of titanium dioxide pigments
Assignee: Wyeth Holdings LLC
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Filing: 1949-12-22
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Granted: 1953-02-17
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Expires: 1969-12-22
Abstract
No abstract record available.
Inventors
- 👤 Jr Charles A Tanner
- 👤 Daniel C Hall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 01:47
CPC Classifications
C; C09; C09C; C09C1/00; C09C1/36; C09C1/3692; C09C3/00; C09C3/04; C09C3/041; C09C3/06; C09C3/063; C01; C01P; C01P2006/00; C01P2006/40; C01P2006/60
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
110 words
A METHOD OF PRODUCING A TITANIUM DIOXIDE PIGMENT OF IMPROVED ELECTRICAL RESISTANCE AND OF IMPROVED TEXTURE, WHICH COMPRISES: WET MILLING AND HYDROCLASSIFYING AN AQUEOUS ALKALINE SLURRY OF CALCINED TITANIUM DIOXIDE CONTAINING WATERSOLUBLE SALTS TO FORM AN AQUEOUS SUSPENSION OF DEFLOCCULATED TITANIUM DIOXIDE PIGMENT PARTICLES, DISSOLVING IN SAID SLURRY AT LEAST SUFFICIENT OF A WATER-SOLUBLE BARIUM COMPOUND TO FLOCCULATE SAID PARTICLES IN SAID SLURRY; ADJUSTING THE PH OF THE FLOCCULATED SLURRY TO SUBSTANTIAL NEUTRALITY; FILTERING SAID SLURRY; WASHING THE FILTER FAKE WITH A WATER SUBSTANTIALLY FREE FROM POLYVALENT METAL CARTIONS UNTIL THE SPECIFIC ELECTRICAL RESISTANCE OF THE TITANIUM DIOXIDE IS AT LEAST 25,000 OHMS; AND DRYING AND PULVERIZING THE FILTER CAKE.
Claim 2
Independent Claim
110 words
A METHOD OF PRODUCING A TITANIUM DIOXIDE PIGMENT OF IMPROVED ELECTRICAL RESISTANCE AND OF IMPROVED TEXTURE, WHICH COMPRISES: WET MILLING AND HYDROCLASSIFYING AN AQUEOUS ALKALINE SLURRY OF CALCINED TITANIUM DIOXIDE CONTAINING WATERSOLUBLE SALTS TO FORM AN AQUEOUS SUSPENSION OF DEFLOCCULATED TITANIUM DIOXIDE PIGMENT PARTICLES, DISSOLVING IN SAID SLURRY AT LEAST SUFFICIENT OF A WATER-SOLUBLE BARIUM COMPOUND TO FLOCCULATE SAID PARTICLES IN SAID SLURRY; ADJUSTING THE PH OF THE FLOCCULATED SLURRY TO SUBSTANTIAL NEUTRALITY; FILTERING SAID SLURRY; WASHING THE FILTER FAKE WITH A WATER SUBSTANTIALLY FREE FROM POLYVALENT METAL CARTIONS UNTIL THE SPECIFIC ELECTRICAL RESISTANCE OF THE TITANIUM DIOXIDE IS AT LEAST 25,000 OHMS; AND DRYING AND PULVERIZING THE FILTER CAKE.
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) | 1956-02-17 | 1956-08-18 | 1957-02-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-02-17 | 1960-08-18 | 1961-02-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-02-17 | 1964-08-18 | 1965-02-17 | $7700.00 | Window Closed / Lapsed |