| 摘要 |
PURPOSE:To prevent mixing of colors from occurring in developed color images formed at a high temperature, by a construction wherein a high-temperature color forming layer comprises a color developer, an intermediate layer comprises an alcohol decolorizing agent, and a low- temperature color forming layer comprises a leuco dye and a specified thiourea derivative. CONSTITUTION:The high-temperature color forming layer, the intermediate layer comprising a decolorizing agent and the low-temperature color forming layer are sequentially laminated on a base in this order. A leuco dye and a color developer based on an organic acid, an inorganic acid or a phenol are incorporated in the high-temperature color forming layer, while an alcohol decolorizing agent is incorporated in the intermediate layer, and a leuco dye and a thiourea derivative of the formula, are incorporated in the low-temperature color forming layer, whereby a leuco multicolor thermal recording material free of mixing of colors in developed color images formed at a high temperature can be obtained. The low-temperature color forming layer is subjected to color development by low energy, while both of the color forming layers are subjected to color development by high energy. With the alcohol decolorizing agent provided in the intermediate layer, when impressed energy is suitably controlled, it is possible to subject the low-temperature color forming layer to decolorization and subject only the high-temperature color forming layer to color development. Accordingly, by changing the impressed energy, it is possible to obtain multicolor images with extremely favorable color separation. |
