Patent US3575948A successfully refreshed from Google Patents.
US3575948A
Expired / Lapsed
US
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Forming small particles of polypropylene by direct polymerization
Assignee: Hercules LLC
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Filing: 1968-03-29
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Granted: 1971-04-20
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Expires: 1988-03-29
Abstract
Abstract POLYPROPYLENE PARTICLES OF LESS THAN 15U ARE PREPARED BY DIRECT POLYMERIZATION USING A SPECIALLY TREATED CATALYST. THE SPECIAL CATALYST TREATMENT COMPRISES PRELIMINARILY TREATING A TRIVALENT TITANIUM CONTAINING CATALYST BY PLYMERIZING A SMALL AMOUNT OF ETHYLENE, PROPYLENE, OR BUTENE-1 THEREWITH AT ELEVATED TEMPERATURE.
Inventors
- 👤 Harry W Blunt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:59
CPC Classifications
C; C08; C08F; C08F110/00; C08F110/04; C08F110/06; Y; Y10; Y10S; Y10S526/00; Y10S526/903; Y10S526/907; Y10S526/909
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) | 1974-04-19 | 1974-10-19 | 1975-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-19 | 1978-10-19 | 1979-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-19 | 1982-10-19 | 1983-04-20 | $7700.00 | Window Closed / Lapsed |