US3721576A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mark forming record materials and process for their use
Assignee: Appvion LLC
•
Filing: 1971-10-01
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Granted: 1973-03-20
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Expires: 1991-10-01
Abstract
Abstract A PRESSURE-SENSITIVE RECORD UNIT AND A MARK-FORMING UNIT ARE DISCLOSED WHICH EMPLOY A CHROMOGENIC MATERIAL OF NORMALLY COLORLESS FORM HAVING THE STRUCTURAL FORMULA: 1''-R,2''-(R1-NH-),3''-R,4''-R,6''-((C2H5-)2N-),4,5,6,7-(CL)4- SPIRO(PHTHALAN-1,9''-XANTHEN-3-ONE WHEREIN R IS HYDROGEN, AN ALKYL RADICAL HAVING 1 TO 4 CARBON ATOMS PER R GROUP OR CHLORINE AND R1 IS HYDROGEN, AN ALKYL RADICAL HAVING 1 TO 4 CARBON ATOMS PER R1 GROUP OR PHENYL.
Inventors
- 👤 S Farber
- 👤 A Wright
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:04
CPC Classifications
B; B41; B41M; B41M5/00; B41M5/124; B41M5/132; B41M5/136; B41M5/145; B41M5/1455; C; C09; C09B; C09B11/00; C09B11/04; C09B11/10; C09B11/24
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) | 1976-03-19 | 1976-09-18 | 1977-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-19 | 1980-09-18 | 1981-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-19 | 1984-09-18 | 1985-03-20 | $7700.00 | Window Closed / Lapsed |