| 摘要 |
PURPOSE:To enhance the sensitivity of the title recording material and to reduce the fading or whitening of a recording image, by using 4-hydroxyphthalic dimethyl ester and/or a specific compound as a coupler and providing an undercoat layer containing the specific compound in adjacent relation to a thermal layer. CONSTITUTION:A thermal color forming layer containing a leuco dye and a coupler as main components is provided to a support. As the coupler, 4- hydroxyphthalic dimethyl ester and/or a compound represented by formula I (wherein R1 is a 1-8C alkyl group, a cycloalkyl group, a substituted or unsubstituted aryl group or a substituted or unsubstituted aralkyl group. As a substituent, a halogen atom or an alkoxy group is designated and an undercoat layer containing a compound represented by formula II (wherein R2 is the same meaning as R1) is provided between the support and the thermal color forming layer in adjacent relation to the thermal color forming layer. The compound represented by the formula II prevents the recrystalization of 4-hydroxyphthalic dimethyl ester and the compound represented by the formula I in the color forming part where both compounds are present in an eutectic state and, therefore, prevent a browning or whitening phenomena. |
