US3836574A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the manufacture of film-and fiber-forming polyesters
Assignee: Hoechst AG
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Filing: 1973-06-20
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Granted: 1974-09-17
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Expires: 1993-06-20
Abstract
Abstract FILM-AND FIBER-FORMING POLYESTERS, OPTIONALLY ALSO POLYESTERS SUITABLE FOR THE PROCESSING OF PLASTIC ARTICLES, ARE PREPARED STARTING FROM DIOLS AND DICARBOXYLIC ACID/DICARBOXYLIC ACID ALKYL ESTER MIXTURE, IN WHICH THE PROPORTION OF THE NUMBER OF FREE CARBOXYL GROUPS SO THAT OF THE ESTERIFIED CARBOXYL GROUPS IS AT LEAST 60:40. THESE STARTING SUBSTANCES ARE REACTED TO FORM THE BIS-DIOL-DICARBOXYLIC ACID ESTERS AND THEIR LOWER OLIGOMERS, AND THESE SUBSTANCES ARE THEN POLYCONDENSED IN KNOWN MANNER TO FORM HIGH MOLECULAR WEIGHT POLYESTERS. PREFERABLY, POLYETHYLENETEREPHTHALATE IS PREPARED ACCORDING TO THIS PROCESS.
Inventors
- 👤 E Achsel
- 👤 S Sommer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:35
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/78
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) | 1977-09-16 | 1978-03-18 | 1978-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-16 | 1982-03-18 | 1982-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-16 | 1986-03-18 | 1986-09-17 | $7700.00 | Window Closed / Lapsed |