Patent US3554976A successfully refreshed from Google Patents.
US3554976A
Expired / Lapsed
US
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Preparation of copolyesters
Assignee: EIDP Inc
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Filing: 1968-07-24
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Granted: 1971-01-12
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Expires: 1988-07-24
Abstract
Abstract UNIFORM COMPOSITION IN POLY(ETHYLENE TEREPHTHALATEAZELATE) IS ACHIEVED BY PREFORMING DIHYDROXYETHYL TEREPHTHALATE, DETERMINING ITS CONCENTRATION OF DIETHYLENE GLYCOL, AND ADDING A QUANTITY OF PREFORMED DIHYDROXYETHYL AZELATE DETERMINED BY REFERENCE TO A TERNARY GRAPH OF GLASS TRANSITION TEMPERATURE DEPRESSION.
Inventors
- 👤 Charles F Hull
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 13:37
CPC Classifications
C; C08; C08J; C08J11/00; C08G; C08G63/00; C08G63/02; C08G63/12; C08G63/16; C08G63/18; C08G63/181; C08G63/183; C08J2367/00; C08J2367/02
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) | 1974-01-11 | 1974-07-13 | 1975-01-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-11 | 1978-07-13 | 1979-01-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-11 | 1982-07-13 | 1983-01-12 | $7700.00 | Window Closed / Lapsed |