US3658745A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Acetalated cross-linked polyvinyl alcohol hydrogels
Assignee: Massachusetts Institute of Technology
•
Filing: 1970-01-14
•
Granted: 1972-04-25
•
Expires: 1990-01-14
Abstract
Abstract AN ACETALATED CROSS-LINKED HYDROGEL CAPABLE OF IMBIBING WATER AND MICROMOLECULAR WATER SOLUTES AND EXCLUDING MACROMOLECULAR WATER SOLUTES BY THE PROCESS OF SWELLING UPON COOLING PREPARED BY REACTING A POLYMER CONTAINING A PLURALITY OF NEAR NEIGHBOR HYDROXYL GROUPS OR CONTAINING HYDROXYL GROUPS AND ETHER GROUPS, A MONOALDEHYDE AND A DIALDEHYDE, THE REAGENTS BEING INITIALLY IN A STATE OF HOMOGENEOUS AQUEOUS SOLUTION.
Inventors
- 👤 Edward W Merrill
- 👤 Patrick Seck-Lai Wong
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:40
CPC Classifications
B; B01; B01J; B01J20/00; B01J20/22; B01J19/00; B01J19/06; C; C08; C08F; C08F8/00; C08F8/48; C08J; C08J5/00; C08J5/18; Y; Y10; Y10S; Y10S524/00; Y10S524/916
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) | 1975-04-25 | 1975-10-25 | 1976-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-25 | 1979-10-25 | 1980-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-25 | 1983-10-25 | 1984-04-25 | $7700.00 | Window Closed / Lapsed |