| 摘要 |
PROBLEM TO BE SOLVED: To reduce the lowering of the developed color density of a diazo thermal recording sheet and to realize high background whiteness and excellent raw preservability by using a specific diazonium salt compd. as a diazo compd. and using a specific compd. as a coupling component. SOLUTION: The diazo compd. on the support of a recording layer is set to a diazonium salt compd. represented by formula I and a coupling component is set to a compd. represented by formula II. In the formula I, R1 -R3 are an alkyl group, an aralkyl group or an aryl group. In the formula II, R4 -R7 are respectively a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, an alkyloxy group, an aryloxy group, alkylthio group, an arylthio group, an acyl group, an alkoxycarbonyl group, an acyloxy group, a carbamoyl group, a sulfamoyl group, a halogen atom, a cyano group or a nitro group. Therefore, the lowering of developed color density can be reduced. |
