US4026977A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of anisotropic semi-permeable membranes of polyaryl ether/sulphones
Assignee: Rhone Poulenc SA
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Filing: 1972-05-19
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Granted: 1977-05-31
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Expires: 1992-05-19
Abstract
Abstract Anisotropic sulphonated polyaryl ether/sulphone membranes having good salt rejection and flow rates making them particularly suitable for use in osmosis and ultrafiltration are provided by casting a solution of the polymer on a support, immersing the supported film in a coagulating bath and then recovering the film, in which:
Inventors
- 👤 Jack Bourganel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:43
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/06; B01D71/66; B01D71/68; B01D67/00; B01D67/0002; B01D67/0009; B01D67/0011; B01D67/0016; B01D67/00165; C; C08; C08L; C08L81/00; C08L81/06; B01D2323/00; B01D2323/08; B01D2323/081; B01D2323/15; B01D2323/16; B01D2323/219; B01D2323/22
Claims Analysis
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References Cited (Backward Citations)
US3567810A
Cited
US3615024A
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US3709841A
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US3551331A
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US3592672A
Cited
US3691068A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-05-30 | 1980-11-29 | 1981-05-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-30 | 1984-11-29 | 1985-05-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-30 | 1988-11-29 | 1989-05-31 | $7700.00 | Window Closed / Lapsed |