| 摘要 |
PURPOSE:To obtain a thermal recording material of high quality excellent in continuous recording properties by a method wherein the mean particle size of at least one of a color forming dye precursor and a developer is set to a specific value or less and a water-soluble high-molecular substance is added to an undercoat layer and the pH of the surface of the dry film of the water-soluble high-molecular substance is specified. CONSTITUTION:The mean particle size of at least one of a color forming dye precursor and a developer is set to 0.7mum or less and the undercoat layer between a thermal recording layer and a support contains a water-soluble high-molecular substance and the surface pH of the dry film of the water-soluble high-molecular substance itself is set to 4-9. Since the water-soluble high-molecular substance is uniformly present in the undercoat layer, the contact area with the thermal recording layer becomes large and the suppressing effect of color forming reaction is increased and the water-soluble high-molecular substance has large effect on the prevention of the lowering of whiteness. When the surface pH of the dry film of the water-soluble high-molecular substance is within the range of 4-9 even if the surface pH of the undercoat layer lowers, the effect of the water-soluble high-molecular substance is developed. When the mean particle size of at least one of the color forming components is set to 0.7mum or less, the compounding effect thereof is markedly developed and large effect is developed in the enhancement of whiteness. |
