Patent US3749697A successfully refreshed from Google Patents.
US3749697A
Expired / Lapsed
US
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Poly(ethylene terephthalate)polyester with lower diethylene glycol content
Assignee: Eastman Kodak Co
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Filing: 1971-12-02
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Granted: 1973-07-31
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Expires: 1991-12-02
Abstract
Abstract FORMATION OF CONTAMINANT DIETHYLENE GLYCOL BY-PRODUCT DURING MANUFACTURE OF POLY(ETHYLENE TEREPHTHALATE) PREPOLYMER BY ESTER EXCHANGE OF DIMETHYL TEREPHTHALATE AND ETHYLENE GLYCOL IN THE PRESENCE OF A CATALYST MIXTURE IS MINIMIZED BY INCLUDING LITHIUM ACETATE DIHYDRATE AS AN ESSENTIAL INGREDIENT IN THE CATALYST MIXTURE WHEN THE CATALYST MIXTURE CONSISTS OF ZINC ACETATE DIHYDRATE OR ANTIMONY TRIOXIDE, ALONE OR TOGETHER, AS THE CATALYST OR CATALYSTS FOR SAID MANUFACTURE.
Inventors
- 👤 K Barkey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:47
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/78; C08G63/82; C08G63/83; C08G63/80
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) | 1976-07-30 | 1977-01-29 | 1977-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-30 | 1981-01-29 | 1981-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-30 | 1985-01-29 | 1985-07-31 | $7700.00 | Window Closed / Lapsed |