Patent US5463618A successfully refreshed from Google Patents.
US2969355A
Expired / Lapsed
US
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Method of preparing cellulose sulfate
Assignee: Eastman Kodak Co
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Filing: 1958-05-15
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Granted: 1961-01-24
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Expires: 1978-05-15
Abstract
No abstract record available.
Inventors
- 👤 Carl J Malm
- 👤 Martin E Rowley
- 👤 Gordon D Hiatt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 05:19
CPC Classifications
C; C08; C08B; C08B5/00; C08B5/14
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
81 words
A METHOD OF PREPARING CELLULOSE SULFATES WHOSE SODIUM SALTS ARE WATER SOLUBLE, WHICH COMPRISES SULFATING CELLULOSE BY REACTING THEREON FOR A TIME WITHIN THE RANGE OF APPROXIMATELY 40 MINUTES TO APPROXIMATELY 420 MINUTES WITH AN ESTERIFICATION BATH ESSENTIALLY CONSISTING OF A HOMOGENEOUS MIXTURE OF SULFURIC ACID, FATTY ACID OF 4-6 CARBON ATOMS AND WATER, THE LATTER IN AN AMOUNT 10-25% OF THE SULFURIC ACID UNTIL AN UNDISSOLVED CELLULOSE HYDROGEN SULFATE HAVING A COMBINED SULFUR CONTENT OF AT LEAST 3% IS OBTAINED.
Claim 2
Independent Claim
81 words
A METHOD OF PREPARING CELLULOSE SULFATES WHOSE SODIUM SALTS ARE WATER SOLUBLE, WHICH COMPRISES SULFATING CELLULOSE BY REACTING THEREON FOR A TIME WITHIN THE RANGE OF APPROXIMATELY 40 MINUTES TO APPROXIMATELY 420 MINUTES WITH AN ESTERIFICATION BATH ESSENTIALLY CONSISTING OF A HOMOGENEOUS MIXTURE OF SULFURIC ACID, FATTY ACID OF 4-6 CARBON ATOMS AND WATER, THE LATTER IN AN AMOUNT 10-25% OF THE SULFURIC ACID UNTIL AN UNDISSOLVED CELLULOSE HYDROGEN SULFATE HAVING A COMBINED SULFUR CONTENT OF AT LEAST 3% IS OBTAINED.
References Cited (Backward Citations)
US2714591A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1964-01-24 | 1964-07-25 | 1965-01-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-01-24 | 1968-07-25 | 1969-01-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-01-24 | 1972-07-25 | 1973-01-24 | $7700.00 | Window Closed / Lapsed |