US2673202A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for the manufacture of high acetyl cellulose acetate
Assignee: Eastman Kodak Co
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Filing: 1951-11-14
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Granted: 1954-03-23
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Expires: 1971-11-14
Abstract
No abstract record available.
Inventors
- 👤 Carlton L Crane
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 23:09
CPC Classifications
C; C08; C08B; C08B3/00; C08B3/06
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
162 words
A METHOD OF PREPARING CELLULOSE ACETATE HAVING AN ACETYL CONTENT OF AT LEAST 44.4%, WHICH COMPRISES ESTERIFYING CELLULOSE AT A TEMPERATURE NOT EXCEEDING 90-200* F. WITH AN ESTERIFICATION BATH ESSENTIALLY CONSISTING OF ACETIC ANHYDRIDE, ACETIC ACID AND A SULFURIC ACID CATALYST, THE BATH CONTAINING SUFFICIENT ACETIC ANHYDRIDE TO SUPPLY 3-6 PARTS THEREOF PER PART OF CELLULOSE, AND TO ASSURE AT LEAST 10% OF ACETIC ANHYDRIDE IN THE BATH AT THE END OF THE ESTERIFICATION, THE SULFURIC ACID CATALYST BEING PRESENT IN A PROPORTION OF 0.2-2%, BASED ON THE WEIGHT OF THE CELLULOSE, AND THE RATIO OF ESTERIFICATION BATH TO CATALYST IN THE ESTERIFICATION BEING WITHIN THE RANGE OF 8:1 TO 15:1, AND WHEN THE ESTERIFICATION IS COMPLETED ADDING WATER TO THE MASS TO BRING IT TO, BUT NOT SUBSTANTIALLY BEYOND, THE GLACIAL POINT, WHILE RAISING THE TEMPERATURE THEREOF TO 140-190* F. AND NEUTRALIZING THE SULFURIC ACID THEREIN, FOLLOWED BY PRECIPITATION OF THE CELLULOSE ESTER IN WATER HAVING A TEMPERATURE OF 180-212* F.
Claim 2
Independent Claim
162 words
A METHOD OF PREPARING CELLULOSE ACETATE HAVING AN ACETYL CONTENT OF AT LEAST 44.4%, WHICH COMPRISES ESTERIFYING CELLULOSE AT A TEMPERATURE NOT EXCEEDING 90-200* F. WITH AN ESTERIFICATION BATH ESSENTIALLY CONSISTING OF ACETIC ANHYDRIDE, ACETIC ACID AND A SULFURIC ACID CATALYST, THE BATH CONTAINING SUFFICIENT ACETIC ANHYDRIDE TO SUPPLY 3-6 PARTS THEREOF PER PART OF CELLULOSE, AND TO ASSURE AT LEAST 10% OF ACETIC ANHYDRIDE IN THE BATH AT THE END OF THE ESTERIFICATION, THE SULFURIC ACID CATALYST BEING PRESENT IN A PROPORTION OF 0.2-2%, BASED ON THE WEIGHT OF THE CELLULOSE, AND THE RATIO OF ESTERIFICATION BATH TO CATALYST IN THE ESTERIFICATION BEING WITHIN THE RANGE OF 8:1 TO 15:1, AND WHEN THE ESTERIFICATION IS COMPLETED ADDING WATER TO THE MASS TO BRING IT TO, BUT NOT SUBSTANTIALLY BEYOND, THE GLACIAL POINT, WHILE RAISING THE TEMPERATURE THEREOF TO 140-190* F. AND NEUTRALIZING THE SULFURIC ACID THEREIN, FOLLOWED BY PRECIPITATION OF THE CELLULOSE ESTER IN WATER HAVING A TEMPERATURE OF 180-212* F.
References Cited (Backward Citations)
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US2000428A
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US2317767A
Cited
US2426982A
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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) | 1957-03-22 | 1957-09-21 | 1958-03-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-03-22 | 1961-09-21 | 1962-03-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-03-22 | 1965-09-21 | 1966-03-23 | $7700.00 | Window Closed / Lapsed |