Patent US3642828A successfully refreshed from Google Patents.
US3642828A
Expired / Lapsed
US
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Alkyl or halo substituted tetrahalofluorans
Assignee: Appvion LLC
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Filing: 1970-11-03
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Granted: 1972-02-15
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Expires: 1990-11-03
Abstract
Abstract 6''-((C2H5-)2-N-)SPIRO(PHTHALAN-1,9''-XANTHENE) WHEREIN EACH R1, R2, R3 OR R4 IS HYDROGEN, AN ALKYL RADICAL HAVING 1 TO 4 CARBON ATOMS OR CHLORINE AND AT LEAST ONE OF SAID R GROUPS IS AN ALKYL RADICAL OR CHLORINE. 3-(O=),4,5,6,7-TETRA(CL-),1''-R1,2''-R2,3''-R3,4''-R4, A CHROMOGENIC MATERIAL OF NORMALLY COLORLESS FORM IS DISCLOSED HAVING THE STRUCTURAL FORMULA:
Inventors
- 👤 Sheldon Farber
- 👤 Arthur John Wright
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 01:12
CPC Classifications
C; C09; C09B; C09B11/00; C09B11/04; C09B11/10; C09B11/24; B; B41; B41M; B41M5/00; B41M5/124; B41M5/132; B41M5/136; B41M5/145; B41M5/1455
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) | 1975-02-14 | 1975-08-16 | 1976-02-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-14 | 1979-08-16 | 1980-02-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-14 | 1983-08-16 | 1984-02-15 | $7700.00 | Window Closed / Lapsed |