| 摘要 |
PURPOSE:To obtain a thermal recording material having high sensitivity and showing little image fading or fingerprint fading, by using specified leuco dyes in combination. CONSTITUTION:At lest one fluoran compound of formula I, wherein R1 is 1-10C alkyl, R2 is 1-4C alkyl, R3 is 1-4C alkylene, R4 is hydrogen, methyl or halogen, and X is halogen or trifluoromethyl, and at least one fluoran compound of formula II, wherein R5 is 1-10C alkyl, R6 is 1-10C alkyl, cycloalkyl or subst. or unsubst. phenyl, R7 is hydrogen, methyl or halogen, and Y is hydrogen, halogen or trifluoromethyl, are used as leuco dyes, in a thermal recording material comprising as main constituents a normally colorless of light-colored leuco dye and a color developer capable of developing the color of the dye when being heated on a base. |
