| 摘要 |
PURPOSE:To obtain a thermal recording material superior in shelf stability of image and resistance to fingerprint and enhanced in reliability with high sensitivity and little possibility of color development in a surface, by a method wherein an undercoat layer containing a novolak-type resin of paraphenylphenol is formed between a substrate and a thermal coloring layer adjacent to the thermal coloring layer. CONSTITUTION:A novolak-type resin of paraphenylphenol used in an undercoat layer is usually in the range of 0.1-5pts.wt., preferably 0.2-2pts.wt., to 1pt.wt. of a leuco dye; that of a softening point ranging 80-150 deg.C is used in view of color developing properties and raw shelf stability. The leuco dyes of one or more sorts are applied in a single or mixed form. A leuco compound of a dye such as triphenyl methane series and fluorane series is preferably used as the leuco dye. As a developer, the one made of a phenolic substance, an inorganic/organic acid substance, and the derivative therefrom can be employed generally in the range of 1-10pts.wt., preferably 2-6pts.wt., to 1pt.wt. of the leuco dye. |
