Patent US2884423A successfully refreshed from Google Patents.
US2884423A
Expired / Lapsed
US
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Phthaloperine derivatives
Assignee: Imperial Chemical Industries Ltd
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Filing: 1956-10-05
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Granted: 1959-04-28
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Expires: 1976-10-05
Abstract
No abstract record available.
Inventors
- 👤 Wilkinson Donald Graham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:40
CPC Classifications
C; C09; C09B; C09B57/00
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
5 words
COLORING MATTER OF THE FORMULA:
Claim 2
Dependent Claim
5 words
COLORING MATTER OF THE FORMULA:
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) | 1962-04-27 | 1962-10-27 | 1963-04-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1966-04-27 | 1966-10-27 | 1967-04-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1970-04-27 | 1970-10-27 | 1971-04-28 | $7700.00 | Window Closed / Lapsed |