Patent US3721650A successfully refreshed from Google Patents.
US3721650A
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Reactive hydroxyalkyl-onium catalysts for synthesis of polyoxazolidones
Assignee: Alelio G D
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Filing: 1971-03-22
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Granted: 1973-03-20
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Expires: 1991-03-22
Abstract
Abstract A PROCESS FOR PREPARING POLYOXAZOLIDONES IS PROVIDED IN WHICH A POLYEPOXIDE IS REACTED WITH A POLYISOCYANATE IN THE PRESENCE OF CHEMICALLY REACTIVE HYDROXYALKYL-ONIUM CATALYSTS, SELECTED FROM THE CLASS OF AMMONIUM AND PHOSPHONIUM HALIDES HAVING AT LEAST TWO HYDROXYALKYL GROUPS. NOVEL POLYMERS ARE OBTAINED WHEN THESE NEW CATALYSTS CONTAINING TWO OR MORE HYDROXY GROUPS ARE CONDENSED WITH POLYISOCYANATES.
Inventors
- 👤 Alelio G D
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:06
CPC Classifications
C; C08; C08G; C08G18/00; C08G18/06; C08G18/08; C08G18/16; C08G18/166; C08G18/168; C08G18/003; C08G18/0804; C08G18/0809; C08G18/18; C08G18/1875; C08G59/00; C08G59/18; C08G59/40; C08G59/4007; C08G59/4014; C08G59/4028; Y; Y10; Y10S; Y10S528/00; Y10S528/905
Claims Analysis
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References Cited (Backward Citations)
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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) | 1976-03-19 | 1976-09-18 | 1977-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-19 | 1980-09-18 | 1981-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-19 | 1984-09-18 | 1985-03-20 | $7700.00 | Window Closed / Lapsed |