US3573132A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the preparation of polyimides
Assignee: Rhone Poulenc SA
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Filing: 1967-10-30
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Granted: 1971-03-30
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Expires: 1987-10-30
Abstract
Abstract IN PREPARING POLYIMIDES, APPROXIMATELY EQUIMOLECULAR QUANTITES OF A TETRACARBOXYLIC ACID DIANHYDRIDE AND A DIPRIMARY DIAMINE ARE MIXED WITH WATER AND DEPOSITED ON A SUPPORT. THE WATER IS SUBSEQUENTLY REMOVED AND THEN THE RESIDUAL MIXTURE OR SUPPORT IS HEATED TO 100* TO 400*C.
Inventors
- 👤 Maurice Ducloux
- 👤 Max Gruffaz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 10:14
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1003; C08G73/1007; C03; C03C; C03C25/00; C03C25/10; C03C25/24; C03C25/26
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) | 1974-03-29 | 1974-09-28 | 1975-03-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-29 | 1978-09-28 | 1979-03-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-29 | 1982-09-28 | 1983-03-30 | $7700.00 | Window Closed / Lapsed |