US2539451A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preparing sulfuric acid esters of cellulose
Assignee: Eastman Kodak Co
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Filing: 1948-02-27
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Granted: 1951-01-30
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Expires: 1968-02-27
Abstract
No abstract record available.
Inventors
- 👤 Carl J Malm
- 👤 Carlton L Crane
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 02:54
CPC Classifications
A; A01; A01K; A01K97/00; A01K97/01; C; C08; C08B; C08B5/00; C08B5/14
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
109 words
A METHOD OF PREPARING CELLULOSE SULFATE WHICH COMPRISES FORMING, AND MIXING CELLULOSE THEREWITH, AT A TEMPERATURE OF 25-60* F., A BATH COMPRISING ISOPROPYL ALCOHOL, CONCENTRATED SULFURIC ACID, AMMONIUM SULFATE IN AN AMOUNT LESS THAN 8% OF THE BATH AND NOT MORE THAN 10% OF WATER, THE ISOPROPYL ALCOHOL-SULFURIC ACID CONSISTING OF 15-25% OF ISOPROPYL ALCOHOL AND 85-75% OF SULFURIC ACID, THE CELLULOSE BEING PRESENT IN THE PROPORTION OF ONE PART OF CELLULOSE TO 12-60 PARTS OF LIQUID, AND THE RATIO OF ALCOHOL-SULFURIC ACID TO CELLULOSE IN THE MASS BEING 4-30:1, AND CONTINUING TO MAINTAIN THE TEMPERATURE AT 25-60* F. UNTIL THE CELLULOSE HAS BEEN CONVERTED TO A CELLULOSE SULFATE.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-01-29 | 1954-07-31 | 1955-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-01-29 | 1958-07-31 | 1959-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-01-29 | 1962-07-31 | 1963-01-30 | $7700.00 | Window Closed / Lapsed |