US2021990A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of treating zinc sulphide or zinc oxide pigment
Assignee: American Zinc Lead and Smelting Co
•
Filing: 1933-06-19
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Granted: 1935-11-26
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Expires: 1953-06-19
Abstract
No abstract record available.
Inventors
- 👤 Harlan A Depew
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 11:45
CPC Classifications
C; C09; C09C; C09C1/00; C09C1/04; C09C1/06; C01; C01P; C01P2004/00; C01P2004/60
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) | 1938-11-25 | 1939-05-27 | 1939-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1942-11-25 | 1943-05-27 | 1943-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1946-11-25 | 1947-05-27 | 1947-11-26 | $7700.00 | Window Closed / Lapsed |