Patent US3444145A successfully refreshed from Google Patents.
US3444145A
Expired / Lapsed
US
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Process for preparing stable polysulfones
Assignee: Shell USA Inc
•
Filing: 1965-02-11
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Granted: 1969-05-13
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Expires: 1985-02-11
Abstract
No abstract record available.
Inventors
- 👤 Edward A Youngman
- 👤 Ronald S Bauer
- 👤 Kenneth C Dewhirst
- 👤 Howard V Holler
- 👤 Hans E Lunk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:01
CPC Classifications
C; C08; C08G; C08G75/00; C08G75/20; C08G75/205; C08G75/22
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2365122A
Cited
US2585583A
Cited
US2864809A
Cited
US3336272A
Cited
US3336273A
Cited
US3336274A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-05-12 | 1972-11-11 | 1973-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-05-12 | 1976-11-11 | 1977-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-05-12 | 1980-11-11 | 1981-05-13 | $7700.00 | Window Closed / Lapsed |