Patent US3689438A successfully refreshed from Google Patents.
US3689438A
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Cation exchange membranes and their preparation
Assignee: Rhone Poulenc SA
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Filing: 1971-03-29
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Granted: 1972-09-05
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Expires: 1991-03-29
Abstract
Abstract CATION EXCHANGE RESINS ARE MADE FROM CROSSLINKED POLY-P-VINYLPHENOLS CONTAINING CATION EXCHANGE GROUPS MIXED WITH AN INERT POLYMER.
Inventors
- 👤 Guy Bourat
- 👤 Rodolphe Margraff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:50
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/20; C08J5/22; C08J5/2206; C08J5/2218; C08J5/2231; C08J5/2243; C08L; C08L25/00; C08L25/18; C08J2325/00; C08J2325/18
Claims Analysis
Total Claims: 0
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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) | 1975-09-05 | 1976-03-06 | 1976-09-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-05 | 1980-03-06 | 1980-09-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-05 | 1984-03-06 | 1984-09-05 | $7700.00 | Window Closed / Lapsed |