Patent US3741940A successfully refreshed from Google Patents.
US3741940A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the preparation and recovery of esterified copolymers containing maleic anhydride
Assignee: Gulf Research and Development Co
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Filing: 1971-05-20
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Granted: 1973-06-26
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Expires: 1991-05-20
Abstract
Abstract THIS INVENTION RELATES TO A METHOD OF RECOVERING THE PARTIALLY ESTERIFIED PRODUCT OF CERTAIN POLYANHYDRIDES, SUCH AS 1-HEXENE-MALEIC ANHYDRIDE COPOLYMERS, FROM SOLUTION WITH THE ESTER CONTENT SUBSTANTIALLY UNCHANGED BY MAINTAINING THE TEMPERATURE DURING THE RECOVERY AT ALL TIMES BELOW ABOUT 80*C. IN THE CASE OF THE METHYL ESTERIFIED COPOLYMERS CONTAINING AT LEAST SOME DIESTER GROUPS, NYDROLYSIS TO CONVERT A PORTION OF THE ESTER GROUPS TO ACID GROUPS OCCURS READILY AT AMBIENT TEMPERATURE UPON CONTACT OF THE COPOLYMERS WITH WATER.
Inventors
- 👤 W Heilman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 20:55
CPC Classifications
C; C08; C08F; C08F8/00
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-25 | 1976-12-25 | 1977-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-25 | 1980-12-25 | 1981-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-25 | 1984-12-25 | 1985-06-26 | $7700.00 | Window Closed / Lapsed |