Recording system utilizing phthalide derivatives as colorless chromogenic material
US4641160A · kind A · utility
7Cited by
4References
1Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Nov 2, 1984 |
| Grant date | Feb 3, 1987 |
| Priority date | — |
| Expiry date | Nov 2, 2004 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB41M5/327
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A new phthalide derivative useful as a colorless chromogenic material has the general formula: ##STR1## wherein R.sub.1 to R.sub.10, X.sub.1, X.sub.2, Y.sub.1, Y.sub.2, Z, a and b have the same meaning as defined hereinbefore.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.