Patent US2985636A successfully refreshed from Google Patents.
US2985636A
Expired / Lapsed
US
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Process for producing pure polyvinyl alcohol
Assignee: Consortium fuer Elektrochemische Industrie GmbH
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Filing: 1955-10-24
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Granted: 1961-05-23
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Expires: 1975-10-24
Abstract
No abstract record available.
Inventors
- 👤 Anselm Hans
- 👤 Smidt Jurgen
- 👤 Winkler Heinz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:08
CPC Classifications
C; C08; C08F; C08F8/00; C08F8/12; Y; Y10; Y10T; Y10T70/00; Y10T70/40; Y10T70/413; Y10T70/437; Y10T70/446; Y10T70/465; Y10T70/474; Y10T70/476
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
85 words
PROCESS FOR PRODUCING PURE POLYVINYL ALCOHOL BY SAPONIFYING A CARBOXYLIC ACID ESTER OF POLYVINYL ALCOHOL IN ADMIXTURE WITH WATER AND AN ACID CATALYST, CHARACTERIZED BY REMOVING THE LIBERATED CARBOXYLIC ACID FROM THE SAPONIFICATION MIXTURE BYU CONTINUOYS EXTRACTION DURING THE SAPONIFICATION WITH A NON-AQUEOUS SOLVENT WHICH IS IMMISCIBLE WITH THE POLYVINYL ALCOHOL SOLUTION AND WHICH IS SELECTED FROM THE GROUP CONSISTING OF ISOPROYL ETHER, 2-BUTANONE, 2-PENTANONE, METYL ISOBUTYL KETONED, ISOPHORONE, TRIBUTYL PHOSPHATE, AND MIXTURES THEREOF, WHICH READILY DISSOLVE SAID ACID WHILE DISSOLVING PRACTICALLY NO POLYVINYL ALCOHOL.
Claim 2
Dependent Claim
85 words
PROCESS FOR PRODUCING PURE POLYVINYL ALCOHOL BY SAPONIFYING A CARBOXYLIC ACID ESTER OF POLYVINYL ALCOHOL IN ADMIXTURE WITH WATER AND AN ACID CATALYST, CHARACTERIZED BY REMOVING THE LIBERATED CARBOXYLIC ACID FROM THE SAPONIFICATION MIXTURE BYU CONTINUOYS EXTRACTION DURING THE SAPONIFICATION WITH A NON-AQUEOUS SOLVENT WHICH IS IMMISCIBLE WITH THE POLYVINYL ALCOHOL SOLUTION AND WHICH IS SELECTED FROM THE GROUP CONSISTING OF ISOPROYL ETHER, 2-BUTANONE, 2-PENTANONE, METYL ISOBUTYL KETONED, ISOPHORONE, TRIBUTYL PHOSPHATE, AND MIXTURES THEREOF, WHICH READILY DISSOLVE SAID ACID WHILE DISSOLVING PRACTICALLY NO POLYVINYL ALCOHOL.
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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) | 1964-05-22 | 1964-11-21 | 1965-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-05-22 | 1968-11-21 | 1969-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-05-22 | 1972-11-21 | 1973-05-23 | $7700.00 | Window Closed / Lapsed |