US3579489A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polymerization of beta-lactones
Assignee: Shell USA Inc
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Filing: 1968-12-20
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Granted: 1971-05-18
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Expires: 1988-12-20
Abstract
Abstract THE MOLECULAR WEIGHT DISTRIBUTION AND HEAT STABILITY OF POLYLACTONES, PARTICULARLY POLY(BETA-LACTONES), ARE CONTROLLED BY POLYMERIZING THE LACTONES IN THE PRESENCE OF AN IONIC INITIATOR AND CERTAIN CHAIN-TRANSFER AGENTS SUCH AS ALPHA-HALO-KETONES, AND ALPHA-HALO-ALDEHYDES.
Inventors
- 👤 Willem M Wagner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:17
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/02; C08G63/06; C08G63/08
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) | 1974-05-17 | 1974-11-16 | 1975-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-17 | 1978-11-16 | 1979-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-17 | 1982-11-16 | 1983-05-18 | $7700.00 | Window Closed / Lapsed |