Thermographic recording compositions
AssigneeSociete Anonyme: Aussedat-Rey
InventorsClaude R. Riou, Jean F. Fayard
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Abstract
The invention relates to novel thermographic recording compositions. Novel color developers for thermographic compositions consist of the compounds of the formula: ##STR1## The invention is useful for recording supports for data generally, for example, computers, medical, etc.
Claims18
A thermographic composition comprising a color former and a color developer, wherein said color developer comprises a compound of the formula:
- ##STR12## wherein n is an integer of from 0 to 4;
- each R independently represents H, alkyl, NO.sub.2, halogen, aryl, NH.sub.2, OH, COOH, SO.sub.3 H, NR.sub.1 R.sub.2, COOR.sub.3, or OR.sub.4 ;
- wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are alkyl or aryl;
- X represents H, a group possessing a labile H capable of forming a stable anion by loss of a proton H.sup.+, and their salts of the formula ##STR13## in which Y represents X minus H and M.sup.+ represents a metal cation.
A method for providing a thermographic color change, said method comprising the step of heating a thermographic composition to a temperature sufficient to cause a color forming reaction between a color former and color developer therein, wherein said color developer comprises a compound to the formula:
- ##STR16## wherein n is an integer of from 0 to 4;
- each R independently represents H, alkyl, NO.sub.2, halogen, aryl, NH.sub.2, OH, COOH, SO.sub.3 H, NR.sub.1 R.sub.2, COOR.sub.3, or OR.sub.4 ;
- wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are alkyl or aryl;
- x represents H, a group possessing a labile H capable of forming a stable anion by loss of proton H.sup.+, and their salts of the formula ##STR17## in which Y represents X minus H and M.sup.+ represents a metal cation.
Dependencies are inferred from the claim text.