Patent US2639281A successfully refreshed from Google Patents.
US2639281A
Expired / Lapsed
US
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Manufacture of carboxymethyl cellulose
Assignee: Acordis UK Ltd
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Filing: 1950-09-20
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Granted: 1953-05-19
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Expires: 1970-09-20
Abstract
No abstract record available.
Inventors
- 👤 Hodge Arthur
- 👤 Drewitt James Gordon Napier
- 👤 Downing John
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:02
CPC Classifications
C; C08; C08B; C08B11/00; C08B11/02; C08B11/04; C08B11/10; C08B11/12
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
92 words
PROCESS FOR THE MANUFACTURE OF CARBOXYMETHYL CELLULOSE WHICH COMPRISES IMPREGNATING CELLULOSE WITH CAUSTIC SODA BY IMMERSING THE CELLULOSE IN A CAUSTIC SODA SOLUTION OF CONCENTRATION 15%-33% AT A TEMPERATURE ABOVE 50* C., SUBJECTING THE IMPREGNATED CELLULOSE TO PRESSURE UNTIL THE MOLECULAR RATIO OF CAUSTIC SODA TO CELLULOSE, AS DETERMINED BY ANALYSIS, RECKONING THE CELLULOSE AS C6H10O5, IS BETWEEN 2.0 AND 3.1 MIXING A COMPOUND SELECTED FROM THE GROUP CONSISTING OF CHLORACETIC ACID AND SODIUM CHLORACETATE WITH THE ALKALI CELLULOSE SO OBTAINED, AND MILLING THE MIXTURE AT A TEMPERATURE KEPT BELOW 25* C.
Claim 2
Dependent Claim
92 words
PROCESS FOR THE MANUFACTURE OF CARBOXYMETHYL CELLULOSE WHICH COMPRISES IMPREGNATING CELLULOSE WITH CAUSTIC SODA BY IMMERSING THE CELLULOSE IN A CAUSTIC SODA SOLUTION OF CONCENTRATION 15%-33% AT A TEMPERATURE ABOVE 50* C., SUBJECTING THE IMPREGNATED CELLULOSE TO PRESSURE UNTIL THE MOLECULAR RATIO OF CAUSTIC SODA TO CELLULOSE, AS DETERMINED BY ANALYSIS, RECKONING THE CELLULOSE AS C6H10O5, IS BETWEEN 2.0 AND 3.1 MIXING A COMPOUND SELECTED FROM THE GROUP CONSISTING OF CHLORACETIC ACID AND SODIUM CHLORACETATE WITH THE ALKALI CELLULOSE SO OBTAINED, AND MILLING THE MIXTURE AT A TEMPERATURE KEPT BELOW 25* C.
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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) | 1956-05-18 | 1956-11-17 | 1957-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-05-18 | 1960-11-17 | 1961-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-05-18 | 1964-11-17 | 1965-05-19 | $7700.00 | Window Closed / Lapsed |