US2582049A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacture of cellulose triacetate
Assignee: Eastman Kodak Co
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Filing: 1950-06-03
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Granted: 1952-01-08
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Expires: 1970-06-03
Abstract
No abstract record available.
Inventors
- 👤 Carl J Malm
- 👤 Carlton L Crane
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:17
CPC Classifications
C; C08; C08B; C08B3/00; C08B3/06
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
162 words
A METHOD FOR PREPARAING A STABLE CELLULOSE ACEATATE HAVING AN ACETYL CONTENT OF AT LEAST 44.3 PERCENT WHICH COMPRISES ACETYLATING CELLULOSE WITH A MIXTURE COMPRISING ACETIC ANHYDRIDE AND SULFURIC ACID CATALYST, NEUTRALIZING 60-90 PER CENT OF THE SULFURIC ACID IN THE MASS WITH A NEUTRALIZING AGENT WHICH FORMS SULFATES INSOLUBLE IN ACETIC ACID, ADDING WATER TO BRING THE MASS TO AND NOT SUBSTANTIALLY BEYOND THE GLACIAL POINT WHILE THE MASS IS MAINTAINED AT A TEMPERATUER OF AT LEAST 110* F., COMPLETELY NEUTRALIZING FREE SULFURIC ACID PRESENT WHILE MAINTAING THE ELEVATED TEMPERATURE BY ADDING A NEUTRAILIZING AGENT WHICH FORMS SULFATES INSOLUBLE IN ACETIC ACID, NOT MORE THAN 10 PER CENT EXCESS OF THE NEUTRALIZING AGENT BEING EMPLOYED, ADDING 1 1/2-50 PER CENT (BASED ON THE LIQUID IN THE BATH) OF ACETIC ANHYDRIDE AND MAINTAINING AT 160-250* F. FOR A TIME WIHTIN THE RANGE OF 6-24 HOURS, SUFFICIENT TO IMPART THE DESIRED ACETYL, FOLLOWED BY SPEARATING THE HIGH ACETYL CELLULOSE ACETATE FROM THE MASS.
Claim 2
Independent Claim
162 words
A METHOD FOR PREPARAING A STABLE CELLULOSE ACEATATE HAVING AN ACETYL CONTENT OF AT LEAST 44.3 PERCENT WHICH COMPRISES ACETYLATING CELLULOSE WITH A MIXTURE COMPRISING ACETIC ANHYDRIDE AND SULFURIC ACID CATALYST, NEUTRALIZING 60-90 PER CENT OF THE SULFURIC ACID IN THE MASS WITH A NEUTRALIZING AGENT WHICH FORMS SULFATES INSOLUBLE IN ACETIC ACID, ADDING WATER TO BRING THE MASS TO AND NOT SUBSTANTIALLY BEYOND THE GLACIAL POINT WHILE THE MASS IS MAINTAINED AT A TEMPERATUER OF AT LEAST 110* F., COMPLETELY NEUTRALIZING FREE SULFURIC ACID PRESENT WHILE MAINTAING THE ELEVATED TEMPERATURE BY ADDING A NEUTRAILIZING AGENT WHICH FORMS SULFATES INSOLUBLE IN ACETIC ACID, NOT MORE THAN 10 PER CENT EXCESS OF THE NEUTRALIZING AGENT BEING EMPLOYED, ADDING 1 1/2-50 PER CENT (BASED ON THE LIQUID IN THE BATH) OF ACETIC ANHYDRIDE AND MAINTAINING AT 160-250* F. FOR A TIME WIHTIN THE RANGE OF 6-24 HOURS, SUFFICIENT TO IMPART THE DESIRED ACETYL, FOLLOWED BY SPEARATING THE HIGH ACETYL CELLULOSE ACETATE FROM THE MASS.
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) | 1955-01-07 | 1955-07-09 | 1956-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1959-01-07 | 1959-07-09 | 1960-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1963-01-07 | 1963-07-09 | 1964-01-08 | $7700.00 | Window Closed / Lapsed |