| 摘要 |
PURPOSE:To provide a thermal recording material having high sensitivity and excellent background whiteness, by containing a leuco dye and a developer in different layers and forming an intermediate layer mainly made of a heat- meltable substance having a m.p. in a specific range between both layers before applying heat-treatment at temp. equal to or higher than the m.p. of the intermediate layer. CONSTITUTION:A heat-meltable substance having a m.p. of 70 to 130 deg.c is applied between a leuco dye layer and a developer layer to form an intermediate layer and heat-treatment is applied at temp. equal to or higher than the m.p. of the intermediate layer to convert the intermediate layer to a uniform thin barrier layer and not only background fog is prevented but also the rapid reaction of the leuco dye with the developer at the time of heating is enabled. When the m.p. of the heat-meltable substance is lower than 70 deg.C, background fog during preservation becomes large and, on the contrary, when higher than 130 deg.C, it is not acceptable because color forming sensitivity becomes inferior. |
