US3639328A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polymers of tetrafluoroethylene
Assignee: Imperial Chemical Industries Ltd
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Filing: 1968-07-01
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Granted: 1972-02-01
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Expires: 1988-07-01
Abstract
Abstract TETRAFLUOROETHYLENE IS POLYMERIZED IN AQUEOUS MEDIUM IN THE PRESENCE OF AN INTERNALLY UNSATURATED PERFLUOROALKENE HAVING THE FORMULA R1-C(-R2)=C(-R3)-R4 IN WHICH R1 AND R3 ARE PERFLUOROALKYL AND R2 AND R4 ARE FLUORINE OR PERFLUOROALKYL IN THE PRESENCE OF A WATER SOLUBLE ORGANIC PEROXIDE AS INITIATOR AND IN THE PRESENCE OF A HIGHLY FLUORINATED ALIPHATIC CARBOXYLIC OR SULFONIC ACID SALT AS EMULSIFIER.
Inventors
- 👤 John Michael Downer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:45
CPC Classifications
H; H01; H01B; H01B3/00; H01B3/18; H01B3/30; H01B3/44; H01B3/443; H01B3/445; C; C08; C08F; C08F14/00; C08F14/18; C08F14/26
Claims Analysis
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-31 | 1975-08-02 | 1976-02-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-31 | 1979-08-02 | 1980-02-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-31 | 1983-08-02 | 1984-02-01 | $7700.00 | Window Closed / Lapsed |