| 摘要 |
PURPOSE:To ensure a high sensitivity, to prevent decoloration from occurring on contact with a plasticizer, an oil or the like and to prevent ground fogging from occurring under hot and humid conditions, by a method wherein a 2,3- dihydroxynaphthalene compound is used jointly as a color developer, and one of said compound and a metallic compound is incorporated in an undercoat layer, while the other is incorporated in a thermal color forming layer. CONSTITUTION:One of a 2,3-dihydroxylnaphthalene compound and a metallic compound is incorporated in an undercost layer while the other is incorporated in a thermal color forming layer, in a thermal recording material comprising an undercoat layer and a thermal color forming layer laminated in this order on a base. The metallic compound may be, for example, an oxide of iron, copper, zinc or the like, a hydroxide of such a metal, or a salt of such a metal with an organic acid such as benzoic acid. The naphthalene compound as the color developer is used in an amount of not less than 20wt% based on the total weight of color developers, preferably, not less than 50wt%. The metallic compound is used in an amount of 0.2-5.0pt.wt. per 1pt.wt. of the naphthalene compound. |
