| 摘要 |
PURPOSE:To enhance the light fastness and storage stability of both of an image and a blank part by providing a thermal color forming layer containing a specific colorless or light-colored leuco dye and a developer on a support and adding a benzotriazole compound to said color forming layer. CONSTITUTION:A thermal color forming layer containing a specific colorless or light-colored leuco dye represented by formula I [wherein R1 is -N(C4H9)2 or -N(iso-C3H11)C2H5] and a developer represented by formula II [wherein R2 is -OCR(CH3)2 or -OH] is provided on a support and a color is formed by the contact of the leuco dye with the developer. Further, a benzotriazole compound represented by formula III (wherein R3, R4 and R5 are a halogen atom or a 1-8C alkyl group) is added to the thermal color forming layer. The leuco dye represented by the formula I has high sensitivity and excellent preservability and the developer represented by the formula II has high whiteness and excellent preservability and, by the addition of the compound represented by the formula III, background color development is prevented and sensitivity is kept. |
