US3686116A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semi-permeable membranes and their use
Assignee: Rhone Poulenc SA
•
Filing: 1969-09-30
•
Granted: 1972-08-22
•
Expires: 1989-09-30
Abstract
Abstract POLYAMIDES OF DIAMINES WITH 5 - AMINO-ISOPHTHALIC ACID MAKE SEMI-PERMEABLE MEMBRANES OF GOOD STABILITY AND SALT REJECTION.
Inventors
- 👤 Andre Rio
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 05:44
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/06; B01D71/56
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
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) | 1975-08-22 | 1976-02-21 | 1976-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-22 | 1980-02-21 | 1980-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-22 | 1984-02-21 | 1984-08-22 | $7700.00 | Window Closed / Lapsed |