Patent US3767620A successfully refreshed from Google Patents.
US3767620A
Expired / Lapsed
US
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Melt stable polyketone compositions
Assignee: EIDP Inc
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Filing: 1971-11-24
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Granted: 1973-10-23
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Expires: 1991-11-24
Abstract
Abstract POLYKETONES DERIVED FROM DIPHENYL ETHER AND TEREPHTHALOYL AND ISOPHTHALOYL HALIDES BY FRIEDEL-CRAFTS SYNTHESIS HAVING SUPERIOR MELT STABILITY, AND A PROCESS FOR THEIR PREPARATION COMPRISING REDUCING XANTHYDROL ENDGROUPS TO XANTHENE GROUPS.
Inventors
- 👤 R Angelo
- 👤 R Darms
- 👤 R Wysong
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:15
CPC Classifications
C; C08; C08G; C08G61/00; C08G61/12; C08G61/127
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) | 1976-10-22 | 1977-04-23 | 1977-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-22 | 1981-04-23 | 1981-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-22 | 1985-04-23 | 1985-10-23 | $7700.00 | Window Closed / Lapsed |