Patent US2607771A successfully refreshed from Google Patents.
US2607771A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of cellulose esters
Assignee: Acordis UK Ltd
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Filing: 1950-07-15
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Granted: 1952-08-19
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Expires: 1970-07-15
Abstract
No abstract record available.
Inventors
- 👤 Groombridge Walter Henry
- 👤 Fisher James Wotherspoon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 13:52
CPC Classifications
C; C08; C08B; C08B3/00
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
117 words
A PROCESS FOR THE CONTINUOUS PRODUCTION OF CELLULOSE ACETATE, WHICH COMPRISES BRINGING INTO CONTACT WITH CELLULOSE AND ACETYLATION MIXTURE COMPRISING ACETIC ANHYDRIDE, A DILUENT THEREFOR WHICH IS A NON-SOLVENT FOR THE CELLULOSE ACETATE AND IS PRESENT IN AMOUNT SUCH THAT THE ACETYLATION MIXTURE AS A WHOLE IS A NON-SOLVENT FOR THE CELLULOSE ACETATE, AND A CATALYST FOR THE ACETYLATION, REMOVING THE ACETYLATION MIXTURE FROM THE CELLULOSE AND IMMEDIATELY REPLACING IT BY FURTHER ACETYLATION MIXTURE HAVING SUBSTANTIALLY THE SAME INITIAL COMPOSITION, ADDING TO AT LEAST THE GREATER PART OF THE ACETYLATION MIXTURE WHICH HAS BEEN REMOVED FROM THE CELLULOSE SUFFICIENT KETENE TO RESTORE ITS CONTENT OF THE ACETIC ANHYDRIDE, AND EMPLOYING THE ACETYLATION MIXTURE AGAIN IN THE PROCESS.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1955-08-19 | 1956-02-18 | 1956-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1959-08-19 | 1960-02-18 | 1960-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1963-08-19 | 1964-02-18 | 1964-08-19 | $7700.00 | Window Closed / Lapsed |