Patent US3560446A successfully refreshed from Google Patents.
US3560446A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the production of high molecular weight polyimides from urethanes
Assignee: Bayer AG
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Filing: 1968-07-30
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Granted: 1971-02-02
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Expires: 1988-07-30
Abstract
Abstract A PROCESS FOR THE PRODUCTION OF POLYMIDES BY REACTION OF CARBAMIC ACID ESTERS AND CYCLIC DICARBOXYLIC ACID ANHYDRIDES AT EMPERATURES OF FROM 0 TO 450*C.
Inventors
- 👤 Wilfried Zecher
- 👤 Rudolf Merten
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:06
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/12; C08G73/1003
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) | 1974-02-01 | 1974-08-03 | 1975-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-01 | 1978-08-03 | 1979-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-01 | 1982-08-03 | 1983-02-02 | $7700.00 | Window Closed / Lapsed |