| 摘要 |
PROBLEM TO BE SOLVED: To obtain a heat-sensitive recording material, in which a color developing sensitivity is high and a photo-fixation is possible and a discoloration is less, by a method wherein a protective layer containing at least one kind of compounds selected form the group consisting of aluminum oxide, aluminum hydroxide, zinc oxide and zinc hydroxide is provided on the surface of a heat- sensitive recording layer. SOLUTION: In order to prevent the whiteness of a heat-sensitive color developing layer containing an oxidative color developing type leuco dye, oxide and photo-reducer from lowering under highly humid state, a protective layer containing at least one kind of compounds selected from the group consisting of aluminum oxide, aluminum hydroxide, zinc oxide and zinc hydroxide. By acting these compounds, which are amphoteric compound, as base, a color developing system is prevented from turning into acid condition, resulting in suppressing unnecessary color development from occurring. The blending amount of the compounds is preferably 5-80wt.% to the solids in the protective layer. Further, the compound is preferably used in the shape of fine solid particles or colloid particles having the particle diameter of 5-200nm. |
