US3832330A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polymerization of tetracarboxylic acid derivatives and urea or urethane derivatives of diamines
Assignee: Imperial Chemical Industries Ltd
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Filing: 1971-10-18
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Granted: 1974-08-27
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Expires: 1991-10-18
Abstract
Abstract MIXTURES OF AROMATIC TETRACARBOXYLIC DIANHYDRIDES AND URETHANE OR UREA DERIVATIVES OF AROMATIC DIAMINES AND SOLUBLE AND FUSIBLE PREPOLYMERS OBTAINED THEREFROM ARE USEFUL INTERMEDIATES FOR FABRICATING POLYMIDE ARTICLES.
Inventors
- 👤 C Turton
- 👤 D Dixon
- 👤 J Rose
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:04
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; 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) | 1977-08-26 | 1978-02-25 | 1978-08-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-26 | 1982-02-25 | 1982-08-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-26 | 1986-02-25 | 1986-08-27 | $7700.00 | Window Closed / Lapsed |