US3817931A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the production of polyesters
Assignee: Imperial Chemical Industries Ltd
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Filing: 1972-01-06
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Granted: 1974-06-18
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Expires: 1992-01-06
Abstract
Abstract POLYESTERS ARE PREPARED BY POLYCONDENSATION OF A BIS(DIHYDRIC ALCOHOL) ESTER OF AROMATIC DICARBOXYLIC ACID USING A DEFINED CATALYST WHICH IS PRODUCED BY REACTING A HYDROXYL BEARING SUPPORT MATERIAL (E.G. ALUMINA) WITH A METAL COMPOUND. THE CATALYST MAY BE GRANULAR AND IN THIS FORM IS FILTERABLE FROM THE PRODUCT POLYMER.
Inventors
- 👤 E Brooks
- 👤 A Morris
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 20:04
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/78; C08G63/82
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) | 1977-06-17 | 1977-12-17 | 1978-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-17 | 1981-12-17 | 1982-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-17 | 1985-12-17 | 1986-06-18 | $7700.00 | Window Closed / Lapsed |