US3542871A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Purification of 4,4'-methylene dianiline by crystallization
Assignee: Pharmacia and Upjohn Co
•
Filing: 1968-07-29
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Granted: 1970-11-24
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Expires: 1988-07-29
Abstract
No abstract record available.
Inventors
- 👤 Edward J Thompson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 10:45
CPC Classifications
C; C08; C08G; C08G18/00; C08G18/06; C08G18/08; C08G18/10; B; B65; B65H; B65H49/00; B65H49/02; B65H49/04; B65H49/06; C07; C07B; C07B63/00
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US3367969A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-11-23 | 1974-05-25 | 1974-11-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-11-23 | 1978-05-25 | 1978-11-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-11-23 | 1982-05-25 | 1982-11-24 | $7700.00 | Window Closed / Lapsed |