US2639239A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heat-treated alkali-metal carboxymethyl cellulose and process of preparing it
Assignee: Hercules Powder Co
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Filing: 1950-11-18
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Granted: 1953-05-19
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Expires: 1970-11-18
Abstract
No abstract record available.
Inventors
- 👤 Edwin S Elliott
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:41
CPC Classifications
C; C08; C08B; C08B11/00; C08B11/20
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
130 words
A PROCESS FOR REDUCING THE SOLUBILITY OF A WATER-SOLUBLE ALKALI-METAL SALT OF CARBOXYMETHYLCELLULOSE HAVING BETWEEN ABOUT 0.5 AND ABOUT 1 CARBOXYMETHYL GROUP FOR EACH ANHYDROGLUCOSE UNIT IN THE CELLULOSE WHICH COMPRISES SUBJECTING THE SAID WATER-SOLUBLE SALT IN A SUBSTANTIALLY DRY AND FINELY-DIVIDED PARTICULATE FORM TO A TEMPERATURE BETWEEN ABOUT 130* C. AND ABOUT 210* C. UNDER TIME AND TEMPERATURE CONDITIONS WITHIN THE AREA ABC AS DEFINED ON THE APPENDED DRAWING TO FORM A HEAT-TREATED SALT OF REDUCED SOLUBILITY CHARACTERIZED BY THE FORMATION OF SEPARATE, DISCRETE, HIGHLY-SWOLLEN GEL PARTICLES SUBSTANTIALLY ALL OF WHICH HAVE DIAMETERS AT LEAST 2 1/2 TIMES, AND A SUBSTANTIAL MAJORITY OF WHICH HAVE DIAMETERS AT LEAST 10 TIMES THE DIAMETERS OF THE DRY PARTICLES WHEN SUSPENDED IN WATER HAVING PH VALUES BETWEEN ABOUT 6 AND ABOUT 10.
Claim 2
Dependent Claim
130 words
A PROCESS FOR REDUCING THE SOLUBILITY OF A WATER-SOLUBLE ALKALI-METAL SALT OF CARBOXYMETHYLCELLULOSE HAVING BETWEEN ABOUT 0.5 AND ABOUT 1 CARBOXYMETHYL GROUP FOR EACH ANHYDROGLUCOSE UNIT IN THE CELLULOSE WHICH COMPRISES SUBJECTING THE SAID WATER-SOLUBLE SALT IN A SUBSTANTIALLY DRY AND FINELY-DIVIDED PARTICULATE FORM TO A TEMPERATURE BETWEEN ABOUT 130* C. AND ABOUT 210* C. UNDER TIME AND TEMPERATURE CONDITIONS WITHIN THE AREA ABC AS DEFINED ON THE APPENDED DRAWING TO FORM A HEAT-TREATED SALT OF REDUCED SOLUBILITY CHARACTERIZED BY THE FORMATION OF SEPARATE, DISCRETE, HIGHLY-SWOLLEN GEL PARTICLES SUBSTANTIALLY ALL OF WHICH HAVE DIAMETERS AT LEAST 2 1/2 TIMES, AND A SUBSTANTIAL MAJORITY OF WHICH HAVE DIAMETERS AT LEAST 10 TIMES THE DIAMETERS OF THE DRY PARTICLES WHEN SUSPENDED IN WATER HAVING PH VALUES BETWEEN ABOUT 6 AND ABOUT 10.
Claim 3
Dependent Claim
74 words
A SUBSTANTIALLY DRY, PARTICULATE, HEATTREATED ALKALI-METAL SALT OF CARBOXYMETHYLCELLULOSE OF REDUCED SOLUBILITY MADE IN ACCORDANCE WITH THE PROCESS OF CLAIM 1 AND CHARACTERIZED BY THE FORMATION OF SEPARATE, DISCRETE, HIGHLYSWOLLEN GEL PARTICLES SUBSTANTIALLY ALL OF WHICH HAVE DIAMETERS AT LEAST 2 1/2 TIMES, AND A SUBSTANTIAL MAJORITY OF WHICH HAVE DIAMETERS AT LEAST 10 TIMES THE DIAMETERS OF THE DRY PARTICLES WHEN SUSPENDED IN WATER HAVING PH VALUES BETWEEN ABOUT 6 AND ABOUT 10.
Claim 4
Dependent Claim
36 words
AN AQUEOUS GEL SUSPENSION COMPRISING A HEAT-TREATED ALKALI-METAL SALT OF CARBOXYMETHYLCELLULOSE OF REDUCED SOLUBILITY, MADE IN ACCORDANCE WITH THE PROCESS OF CLAIM 1, SUSPENDED IN WATER HAVING A PH VALUE BETWEEN ABOUT 6 AND ABOUT 10.
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) | 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 |