| 摘要 |
PURPOSE:To enhance preservation stability and oil resistance of a developed color image and a non-image area, by a method wherein a benzoic or naphthoic acid derivative having an acyloxy group adjacent to a carboxyl group is used as a color developer, and a zinc compound is added to a color forming layer. CONSTITUTION:Acyloxybenzoic or acyloxynaphthoic acid of the formula (wherein each of R<1>-R<8> is an alkyl group, an aryl group, an aralkyl group or the like; each of R<1>, R<3>, R<5> and R<7> may be halogen; n1 is an integer of 0-4; and each of n2-n4 is an integer of 0-6) is incorporated as a color developer into a thermal color forming layer forming material comprising an ordinary leuco dye together with a binder or the like, and a zinc compound such as zinc chloride or zinc propionate is further added to the material. The color developer and the zinc compound are used in the color forming layer in a total amount of 30- 80wt%, and the zinc compound is used in an amount of 0.1-10pts.wt., preferably 0.3-5pts.wt. per pt.wt. of the color developer. The leuco dye is used in an amount of 5-30wt% in the color forming layer. |
