Patent US3459640A successfully refreshed from Google Patents.
US3459640A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the purification of lactams
Assignee: Teijin Ltd
•
Filing: 1966-04-06
•
Granted: 1969-08-05
•
Expires: 1986-04-06
Abstract
No abstract record available.
Inventors
- 👤 Shigemitsu Tsunawki
- 👤 Yutaka Furusawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 06:54
CPC Classifications
C; C07; C07D; C07D201/00; C07D201/02; C07D201/12
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
US2605261A
Cited
US2667483A
Cited
FR1317839A
Cited
US3156683A
Cited
US2405969A
Cited
GB757406A
Cited
GB850437A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-08-04 | 1973-02-03 | 1973-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-08-04 | 1977-02-03 | 1977-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-08-04 | 1981-02-03 | 1981-08-05 | $7700.00 | Window Closed / Lapsed |