US3578700A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing poly (beta-lactone) prepolymers
Assignee: Shell USA Inc
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Filing: 1968-03-29
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Granted: 1971-05-11
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Expires: 1988-03-29
Abstract
Abstract POLY(BETA-LACTONE) PREPOLYMERS HAVING A MOLECULAR WEIGHT OF FROM ABOUT 200 TO 10,000 AND WHICH ARE ESPECIALLY SUITABLE AS INITIATORS FOR THE POLYMERIZATION OF POLY(BETA-LACTONES) ARE PREPARED BY REACTING A BETALACTONE AND PREFERABLY AN ALPHA,ALPHA-DIALKYL-BETA-PROPIOLACTONE WITH A NUCLEOPHILIC AGENT AS HEREINAFTER MORE FULLY DESCRIBED SUCH AS THE TERTIARY PHOSPHINES, IN A MOLAR RATIO OF 20:1 TO 1:40.
Inventors
- 👤 Arie Klootwijk
- 👤 Willem Bergwerf
- 👤 Willem M Wagner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:38
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/78; C08G63/82; C08G63/823
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) | 1974-05-10 | 1974-11-09 | 1975-05-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-10 | 1978-11-09 | 1979-05-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-10 | 1982-11-09 | 1983-05-11 | $7700.00 | Window Closed / Lapsed |