| 摘要 |
PROBLEM TO BE SOLVED: To provide a developer for colorable dyes comprising a novel allylidene bis-coumalin derivative and a thermal recording material having the excellent preservation stability of a colored image and sufficient coloring density by containing the developer. SOLUTION: A developer for colorable dyes comprises an allylidene bis- coumalin derivative which is given by a formula (wherein n is an integer of 1-3; R1 is a group selected from the group consisting of linear or branched alkyl, alkoxy, aralkyloxy, alkoxycarbonyl, aralkyloxycarbonyl, alkoxycarbonylalkyloxy, aralkyloxycarbonylalkyloxy, hydroxyl, carboxyl, nitrile, halogen, and methylenedioxy groups, which can be different from each other when n is 2 or more; R2 is a group selected from the group consisting of hydrogen, linear or branched alkyl, alkoxy, dialkylamino, and hydroxyl groups). A thermal recording material containing the developer is obtained. |
