| 摘要 |
PURPOSE:To especially enhance the fastnesses of a white background part and an image part, in a thermal color forming material by a new reaction system different from the reaction system of an electron donating colorless dye and an electron acceptive compd., by adding an indoxyl derivative represented by a specific general formula. CONSTITUTION:In thermal color forming material by a new reaction system different from the reaction system of an electron donating colorless dye and an electron acceptive compd., an indoxyl derivative represented by general formula wherein R<1> and R<2> may be same as or different from each other and are each hydrogen atom, an alkyl group or a substituted sulfonyl group and R<3>-R<6> may be same as or different from each other and are a hydrogen atom, an alkyl group, a substitutable amino group or a sulfonyl group and may be bonded mutually to form a ring). By this constitution, a thermal recording material especially improved in the fastness of a white background part and a developed color image is obtained. |
