US2604477A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Leuco sulfuric acid esters of trianthrimide carbazole dyestuffs and method for producing the same
Assignee: Imperial Chemical Industries Ltd
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Filing: 1947-11-18
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Granted: 1952-07-22
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Expires: 1967-11-18
Abstract
No abstract record available.
Inventors
- 👤 Coffey Samuel
- 👤 Fairweather David Alexan Whyte
- 👤 Slinger Frank Hayhurst
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:59
CPC Classifications
C; C09; C09B; C09B9/00; C09B9/02
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
48 words
A PROCESS FOR THE PRODUCTION OF THE LEUCO SULFURIC ESTER DYESTUFF OF 1:1'':5:1:1''''-TRIANTHRIMIDE-2:2'':6:2''''-CARBAZOLE CHARACTERIZED IN THAT THE FORMATION OF THE LEUCO SULFURIC ESTER IS CARRIED OUT IN THE PRESENCE OF A NON-VATTABLE COMPOUND SELECTED FROM THE GROUP CONSISTING OF AMIDES OF CARBOXYLIC AND SULPHONIC ACIDS HAVING THE FORMULA
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) | 1955-07-22 | 1956-01-21 | 1956-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1959-07-22 | 1960-01-21 | 1960-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1963-07-22 | 1964-01-21 | 1964-07-22 | $7700.00 | Window Closed / Lapsed |