| 摘要 |
PURPOSE:To obtain a developed 2-color image in accordance with heating conditions by using only one kind of color forming components, by utilizing the first color forming reaction of a leuco dye based on fluoran and a phenolic acidic substance and the second color forming reaction of the leuco dye, the acidic substance and an aliphatic amine compound. CONSTITUTION:A fluoran compound of formula I (wherein each of R<1> and R<2> is hydrogen or a 1-10C alkyl group, and each of Y<1> and Y<2> is hydrogen or a polar substituent group such as Cl or CF3), a phenolic compound such as gallic acid or salicylic acid, and an aliphatic primary or secondary amine compound of formula II (wherein each of R<5> and R<6> is hydrogen, a 1-30C alkyl group, an amino-substituted alkyl group or the like) in a quantity of 1-20pts.wt. per 1pts.wt. of the leuco dye are applied to a base together with an ordinary binder and auxiliary additive components to produce a thermal color forming layer. When the color forming layer is heated to a low temperature, the color reaction of only the leuco dye and the phenolic substance is induced, and when the layer is heated to a high temperature, the second color reaction of the leuco dye, the phenolic substance and the amine compound is induced to form a color different from that of the former color reaction. |
