US3705890A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cellulose carbonates and methods for their preparation
Assignee: Ranks Hovis McDougall Ltd
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Filing: 1970-12-14
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Granted: 1972-12-12
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Expires: 1990-12-14
Abstract
Abstract CELLULOSE CARBONATE IS PREPARED BY REACTING CELLULOSE OR A 6-SUBSTITUTED CELLULOSE, E.G. METHYL CELLULOSE, HYDROXYETHYL CELLULOSE, CARBOMETHYL CELLULOSE AND DIETHYLAMINOETHYL WITH AN ALKYL OR ARYL CHLOROFORMATE.
Inventors
- 👤 Sidney Alan Barker
- 👤 John Frederick Kennedy
- 👤 Charles John Gray
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 06:42
CPC Classifications
C; C08; C08B; C08B7/00; C08B11/00; C08B11/20; C08B13/00; C08B15/00; C08B15/05; C08B15/06; C08B3/00; C08B3/14; C08B3/22; C08B5/00; C12; C12N; C12N11/00; C12N11/02; C12N11/10; C12N11/12; C13; C13K; C13K1/00; C13K1/06
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) | 1975-12-12 | 1976-06-12 | 1976-12-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-12-12 | 1980-06-12 | 1980-12-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-12-12 | 1984-06-12 | 1984-12-12 | $7700.00 | Window Closed / Lapsed |