Patent US3709877A successfully refreshed from Google Patents.
US3709877A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the sulfation of cellulosic ethers
Assignee: Johnson and Johnson
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Filing: 1972-03-07
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Granted: 1973-01-09
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Expires: 1992-03-07
Abstract
Abstract A PROCESS FOR MANUFACTURING SULFATED ALKALI CELLULOSE ETHERS BY REACTING TOGETHER CELLULOSIC ETHERS AND SULFATING AGENTS IN AN ORGANIC DILUENT MEDIUM. THE REACTED MIXTURE IS THEN COMBINED WITH WATER TO FORM A MOTHER LIQUOR FROM WHICH THE SULFATED CELLULOSE ETHERS ARE PRECIPITATED. BY CAREFULLY CONTROLLING THE CONCENTRATION PARAMETERS OF THE MOTHER LIQUOR, A PRODUCT WILL PRECIPITATE WHICH CAN BE CAST INTO A FILM CAPABLE OF RAPIDLY DISSOLVING IN WATER. SPECIFICALLY, THE MOTHER LIQUOR SHOULD BE CONTROLLED TO MAINTAIN A PH OF AT LEAST ABOUT 3.8 AND A CATION CONCENTRATION OF A PRESCRIBED LEVEL.
Inventors
- 👤 D Tunc
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:59
CPC Classifications
C; C08; C08B; C08B11/00; C08B11/20; C08B11/22; C08B13/00
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) | 1976-01-09 | 1976-07-10 | 1977-01-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-09 | 1980-07-10 | 1981-01-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-09 | 1984-07-10 | 1985-01-09 | $7700.00 | Window Closed / Lapsed |