Patent US3156012A successfully refreshed from Google Patents.
Patent US3753957A successfully refreshed from Google Patents.
US3753957A
Expired / Lapsed
US
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Process for preparing aromatic polyamides by condensation of an aromatic ester of an aromatic amino acid
Assignee: Celanese Corp
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Filing: 1971-12-09
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Granted: 1973-08-21
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Expires: 1991-12-09
Abstract
Abstract HIGH MOLECULAR WEIGHT AROMATIC LINEAR POLYAMIDES OF FIBER-FORMING GRADE ARE PREPARED BY CONDENSATION OF MONOMERIC AROMATIC ESTERS OF AROMATIC AMINO ACID TO FORM A SOLID OLIGMER, FOLLOWED BY SUBSEQUENT SOLID STATE POLYMERIZATION OF THE OLIGOMER TO PRODUCE HIGH VISCOSITY LINEAR AROMATIC POLYAMIDE. THE DESCRIBED PROCESS IS PARTICULARLY ADVANTAGEOUS ECONOMICALLY BECAUSE OF THE HIGH YIELD OF FIBER FILM AND COATING GRADE POLYMER COUPLED WITH THE ABILITY TO RECOVER THE BY-PRODUCT FOR RECYCLE TO FROM THE MONOMERIC AROMATIC ESTER STARTING MATERIAL.
Inventors
- 👤 R Jones
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:50
CPC Classifications
C; C08; C08G; C08G69/00; C08G69/02; C08G69/08; C08G69/12; 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) | 1976-08-20 | 1977-02-19 | 1977-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-20 | 1981-02-19 | 1981-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-20 | 1985-02-19 | 1985-08-21 | $7700.00 | Window Closed / Lapsed |