US3520852A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of preparing polyimides of styrene-maleic anhydride polymers
Assignee: Sinclair Research Inc
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Filing: 1967-10-19
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Granted: 1970-07-21
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Expires: 1987-10-19
Abstract
No abstract record available.
Inventors
- 👤 Richard J Pratt
- 👤 Robert J Conboy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 08:24
CPC Classifications
C; C08; C08F; C08F8/00; C08F8/30; C08F8/32; C08F2800/00; C08F2800/10; C08F2810/00; C08F2810/50
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-07-20 | 1974-01-19 | 1974-07-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-07-20 | 1978-01-19 | 1978-07-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-07-20 | 1982-01-19 | 1982-07-21 | $7700.00 | Window Closed / Lapsed |