Patent US2588051A successfully refreshed from Google Patents.
US2588051A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of cellulose esters
Assignee: Akzo Nobel UK PLC
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Filing: 1950-07-10
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Granted: 1952-03-04
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Expires: 1970-07-10
Abstract
No abstract record available.
Inventors
- 👤 Eric P Sharman
- 👤 Donald L Wilson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:27
CPC Classifications
C; C08; C08B; C08B3/00; C08B3/22; C08B3/24
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
110 words
IN A PROCESS FOR THE PRODUCTION OF SECONDARY CELLULOSE ACETATE BY ACETYLATING CELLULOSE IN THE PRESENCE OF METHYLENE CHLORIDE TO FORM A CELLULOSE TRIACETATE SOLUTION CONTAINING FROM 50 TO 60 PER CENT OF METHYLENE CHLORIDE AND HYDROLYSING THE CELLULOSE TRIACETATE WHILE STILL IN SOLUTION TO A SECONDARY CELLULOSE ACETATE, THE IMPROVEMENT WHICH COMPRISES DISTILLING METHYLENE CHLORIDE FROM THE SOLUTION BEFORE THE HYDROLYSIS IS COMPLETED TO REMOVE FROM 45 TO 60 PER CENT BY WEIGHT OF THE METHYLENE CHLORIDE AND TO DECREASE THE METHYLENE CHLORIDE CONTENT TO FROM 30 TO 45 PER CENT BY WEIGHT BASED ON THE WEIGHT OF THE ORIGINAL SOLUTION, WHEREBY THE TIME FOR HYDROLYSIS IS SUBSTANTIALLY REDUCED.
Claim 2
Dependent Claim
110 words
IN A PROCESS FOR THE PRODUCTION OF SECONDARY CELLULOSE ACETATE BY ACETYLATING CELLULOSE IN THE PRESENCE OF METHYLENE CHLORIDE TO FORM A CELLULOSE TRIACETATE SOLUTION CONTAINING FROM 50 TO 60 PER CENT OF METHYLENE CHLORIDE AND HYDROLYSING THE CELLULOSE TRIACETATE WHILE STILL IN SOLUTION TO A SECONDARY CELLULOSE ACETATE, THE IMPROVEMENT WHICH COMPRISES DISTILLING METHYLENE CHLORIDE FROM THE SOLUTION BEFORE THE HYDROLYSIS IS COMPLETED TO REMOVE FROM 45 TO 60 PER CENT BY WEIGHT OF THE METHYLENE CHLORIDE AND TO DECREASE THE METHYLENE CHLORIDE CONTENT TO FROM 30 TO 45 PER CENT BY WEIGHT BASED ON THE WEIGHT OF THE ORIGINAL SOLUTION, WHEREBY THE TIME FOR HYDROLYSIS IS SUBSTANTIALLY REDUCED.
References Cited (Backward Citations)
GB337366A
Cited
US1990625A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1955-03-04 | 1955-09-03 | 1956-03-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1959-03-04 | 1959-09-03 | 1960-03-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1963-03-04 | 1963-09-03 | 1964-03-04 | $7700.00 | Window Closed / Lapsed |