Patent US3157618A successfully refreshed from Google Patents.
US3157618A
Expired / Lapsed
US
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Oxides of tin as catalysts in the preparation of polyesters
Assignee: PPG Industries Inc
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Filing: 1959-03-31
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Granted: 1964-11-17
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Expires: 1979-03-31
Abstract
No abstract record available.
Inventors
- 👤 Bras Louis R Le
- 👤 Donald F Stahr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 03:10
CPC Classifications
C; C08; C08G; C08G18/00; C08G18/06; C08G18/28; C08G18/40; C08G18/42; C08G63/00; C08G63/02; C08G63/12; C08G63/16; C08G63/20; C08G63/78; C08G63/82; C08G63/85
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
114 words
A METHOD OF PREPARING A POLYMERIC POLYESTER WHICH COMPRISES FORMING A MIXTURE OF: (A) A FREE ALCOHOL CONTAINING AT LEAST TWO HYDROXYL GROUPS; (B) A FREE CARBONYL COMPOUND SELECTED FROM THE CLASS CONSISTING OF A DICARBOXYLIC ACID AND THE ANHYDRIDE THEREOF, SAID ALCOHOL AND SAID COMPOUND CONSISTING OF ATOMS OF CARBON, HYDROGEN AND OXYGEN, THE ALCOHOL BEING PRESENT IN AN AMOUNT TO PROVIDE A POLYESTER HAVING A HYDROXYL VALUE IN A RANGE BETWEEN 40 AND 700; AND (C) STANNOUS OXIDE, AND HEATING THE MIXTURE TO A TEMPERATURE TO EVOLVE WATER AND TO FORM SAID POLYMERIC POLYESTER BY DIRECT ESTERFICATION REACTION, HEATING BEING CONTINUED UNTIL AN ACID VALUE OF LESS THAN ABOUT 3 IS ATTAINED.
Claim 2
Independent Claim
114 words
A METHOD OF PREPARING A POLYMERIC POLYESTER WHICH COMPRISES FORMING A MIXTURE OF: (A) A FREE ALCOHOL CONTAINING AT LEAST TWO HYDROXYL GROUPS; (B) A FREE CARBONYL COMPOUND SELECTED FROM THE CLASS CONSISTING OF A DICARBOXYLIC ACID AND THE ANHYDRIDE THEREOF, SAID ALCOHOL AND SAID COMPOUND CONSISTING OF ATOMS OF CARBON, HYDROGEN AND OXYGEN, THE ALCOHOL BEING PRESENT IN AN AMOUNT TO PROVIDE A POLYESTER HAVING A HYDROXYL VALUE IN A RANGE BETWEEN 40 AND 700; AND (C) STANNOUS OXIDE, AND HEATING THE MIXTURE TO A TEMPERATURE TO EVOLVE WATER AND TO FORM SAID POLYMERIC POLYESTER BY DIRECT ESTERFICATION REACTION, HEATING BEING CONTINUED UNTIL AN ACID VALUE OF LESS THAN ABOUT 3 IS ATTAINED.
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) | 1967-11-17 | 1968-05-18 | 1968-11-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1971-11-17 | 1972-05-18 | 1972-11-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1975-11-17 | 1976-05-18 | 1976-11-17 | $7700.00 | Window Closed / Lapsed |