| 摘要 |
PURPOSE:To provide a thermal recording material having a high sensitivity and less susceptible to fading or blushing of recorded images, by using a combination of specified compounds as a color developer. CONSTITUTION:Compounds of general formulas (I), (II) and (III) are used in combination as a color developer, in a thermal recording material utilizing a color forming reaction of a leuco dye and the color developer. In formula (I), n represents 1 or 2. In formula (II), X represents a halogen, Y represents SO2 or -C(CH3)2-, m represents 1 or 2, and the groups X on the left and right benzene rings are at positions symmetrical with respect to Y. The compound of formula (I) has a melting respect to Y. The compound of formula (I) has a melting point of 100-150 deg.C and a high color developing capability, thereby ensuring high heat response characteristics and an excellent uniformity of developed color images. Though the compounds of formulas (II) and (III) have melting points much higher than that of the compound of formula (I), they form a eutectic when the three compounds are used in mixture, thereby preventing the compound of formula (I) from being recrystallized at a developed color part, so that the phenome non of fading or bushing is prevented from occurring. The color developer is used generally in an amount of 1-10pts.wt. per 1pts.wt. of the leuco dye. The color develop ing substances of formulas (I), (II) and (III) are used in a weight ratio of 1:1:1-10:1:1. |
