US3775368A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Aromatic polymers of 2-bromo-8-hydroxy-5,5-dioxodibenzothiophen
Assignee: Imperial Chemical Industries Ltd
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Filing: 1972-01-31
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Granted: 1973-11-27
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Expires: 1992-01-31
Abstract
Abstract NEW AROMATIC POLYMERS COMPRISING UNITS OF THE FORMULA -O-(5,5-DI(O=)DIBENZOTHIOPHEN-8,2-YLENE)- AND COPOLYMERS COMPRISING SUCH UNITS AND OTHER UNITS SUCH AS -O-(1,4-PHENYLENE)-SO2-(1,4-PHENYLENE)- ARE OF HIGHER SOFTENING POINT THAN POLYMERS OF THE LATTER UNITS ALONE. THE NEW POLYMERS MAY BE MADE USING AN ALKALI METAL SALT OF 2-BROMO-8-HYDROXY-5,5-DIOXODIBENZOTHIOPHEN AS MONOMER OR BY REACTING 2,8-DIBROMO-5,5DIOXODIBENZOTHIOPHEN WITH AN EQUIVALENT AMOUNT OF AN ALKALI METAL HYDROXIDE OR A DI-(ALKALI METAL) SALT OF A BISPHENOL.
Inventors
- 👤 V Leslie
- 👤 A Newton
- 👤 J Rose
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 10:21
CPC Classifications
C; C07; C07D; C07D333/00; C07D333/50; C07D333/76; C08; C08G; C08G65/00; C08G65/34; C08G65/38; C08G75/00; C08G75/20; C08G75/23
Claims Analysis
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References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-26 | 1977-05-28 | 1977-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-26 | 1981-05-28 | 1981-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-26 | 1985-05-28 | 1985-11-27 | $7700.00 | Window Closed / Lapsed |