US3050508A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing pure polyvinyl alcohol
Assignee: Hoechst AG
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Filing: 1959-12-08
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Granted: 1962-08-21
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Expires: 1979-12-08
Abstract
No abstract record available.
Inventors
- 👤 Starck Werner
- 👤 Kahrs Karl-Heinz
- 👤 Ehmann Werner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 06:57
CPC Classifications
C; C08; C08F; C08F8/00; C08F8/12; C08J; C08J5/00; C08J5/18
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
159 words
A PROCESS FOR THE MANUFACTURE OF POLYVINYL ALCOHOL IN A POWDERY FILTERABLE FORM ADAPTABLE TO WASHING IN COLD WATER WITHOUT SWELLING AND CONTAINING NO MORE THAN 11.5 PERCENT OF UNHYDROLYZED ACYL GROUPS, WHICH PROCESS COMPRISES SAPONIFYING AN ESTER OF POLYVINYL ALCOHOL AND AN ALIPHATIC MONOCARBOXYLIC ACID HAVING 1 TO 10 CARBON ATOMS AT A TEMPERATURE IN THE RANG E BETWEEN 10*C. AND 120*C. IN A SAPONIFICATION MIXTURE OF 0.1 TO 10 PERCENT BY WEIGHT OF AT LEAST ONE STRONG ACID AS A SAPONIFICATION CATALYST, 0.5 TO 15 PERCENT BY WEIGHT OF WATER, THE BALANCE BEING A MIXTURE OF SAID ESTER AND A WATER-MISCIBLE AND ACID-MISCIBLE SOLVENT WHICH IS INERT TO SAID CARBOXYLIC ACID AND WHICH IS A NON-SOLVENT FOR POLYVINYL ALCOHOL, SAID ESTER BEING PRESENT AS 1 TO 50 PERCENT BY WEIGHT OF SAID SOLVENT IN THE ESTER-SOLVENT MIXTURE, WHEREBY POLYVINYL ALCOHOL IS PRECIPITATED IN POWDERY FORM WITH THE SIMULTANEOUS FORMATION OF FREE CARBOXYLIC ACID FROM THE ESTER SAPONIFIED.
Claim 2
Dependent Claim
159 words
A PROCESS FOR THE MANUFACTURE OF POLYVINYL ALCOHOL IN A POWDERY FILTERABLE FORM ADAPTABLE TO WASHING IN COLD WATER WITHOUT SWELLING AND CONTAINING NO MORE THAN 11.5 PERCENT OF UNHYDROLYZED ACYL GROUPS, WHICH PROCESS COMPRISES SAPONIFYING AN ESTER OF POLYVINYL ALCOHOL AND AN ALIPHATIC MONOCARBOXYLIC ACID HAVING 1 TO 10 CARBON ATOMS AT A TEMPERATURE IN THE RANG E BETWEEN 10*C. AND 120*C. IN A SAPONIFICATION MIXTURE OF 0.1 TO 10 PERCENT BY WEIGHT OF AT LEAST ONE STRONG ACID AS A SAPONIFICATION CATALYST, 0.5 TO 15 PERCENT BY WEIGHT OF WATER, THE BALANCE BEING A MIXTURE OF SAID ESTER AND A WATER-MISCIBLE AND ACID-MISCIBLE SOLVENT WHICH IS INERT TO SAID CARBOXYLIC ACID AND WHICH IS A NON-SOLVENT FOR POLYVINYL ALCOHOL, SAID ESTER BEING PRESENT AS 1 TO 50 PERCENT BY WEIGHT OF SAID SOLVENT IN THE ESTER-SOLVENT MIXTURE, WHEREBY POLYVINYL ALCOHOL IS PRECIPITATED IN POWDERY FORM WITH THE SIMULTANEOUS FORMATION OF FREE CARBOXYLIC ACID FROM THE ESTER SAPONIFIED.
References Cited (Backward Citations)
US2360308A
Cited
US2569470A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1965-08-20 | 1966-02-19 | 1966-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1969-08-20 | 1970-02-19 | 1970-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1973-08-20 | 1974-02-19 | 1974-08-21 | $7700.00 | Window Closed / Lapsed |