US3679636A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Formation of aromatic polyamides in gammabutyrolactone as mutual solvent for aromatic diamines,and 2,6-lutidine
Assignee: Celanese Corp
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Filing: 1969-09-26
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Granted: 1972-07-25
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Expires: 1989-09-26
Abstract
Abstract AROMATIC DIAMINES AND AROMATIC DIACID HALIDES ARE REACTED TO FORM HIGH-MOLECULAR WEIGHT POLYAMIDES IN A MUTUAL SOLVENT SYSTEM COMPRISING ANHYROUS GAMMABUTYROLACTONE AND AT LEAST ONE AMINE ACID ACCEPTOR, E.G., 2,6-LUTIDINE.
Inventors
- 👤 Elliot A Vogelfanger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:42
CPC Classifications
C; C08; C08G; C08G69/00; C08G69/02; C08G69/26; C08G69/32
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) | 1975-07-25 | 1976-01-24 | 1976-07-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-25 | 1980-01-24 | 1980-07-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-25 | 1984-01-24 | 1984-07-25 | $7700.00 | Window Closed / Lapsed |