| 摘要 |
PURPOSE:To obtain excellent storage stability over a long period of time without generating precoupling, by using a salt formed of a specific guanidine derivative and a hydroxynaphthoic acid derivative. CONSTITUTION:A thermal recording layer containing a diazonium compound and at least one or more of a salt formed of a guanidine derivative represented by formula I and a hydroxynaphthoic acid derivative represented by formula II is provided to a support. In formulae I, II, R1, R2, R3, R4, R5 and R6 are an aryl group which may be substituted with an alkyl group, an alkoxyl group, a nitro group or a halogen atom; an aralkyl group which may be substituted with an alkyl group, an alkoxyl group, a nitro group or a halogen atom; an alkyl group; a cycloalkyl group or a hydrogen atom. The salt of these derivatives is formed by adding both derivatives in a solvent dissolving at least one of said derivatives, for example, alcohol in an almost equimolar ratio and refluxing the resulting solution for several hr. |
