| 摘要 |
PURPOSE:To obtain a thermal recording material showing little fading of images due to oils or fingerprints and having excellent thermal response characteristics, by using a monoester compound of bis(4-hydroxyphenyl)sulfone of a specified formula as a color developer. CONSTITUTION:A monoester compound of bis(4-hydroxyphenyl)sulfone of formula (I), wherein R1 is hydrogen or methyl, is used as a color developer, in a thermal recording material utilizing a color forming reaction between a leuco dye and the color developer. The compound ensures excellent stability of a developed color image part, and rarely generate image deterioration due to temperature or moisture or image fading due to a plasticizer, oil or the like. A color developer consisting of a known phenolic substance, inorganic or organic acidic substance or derivative thereof may be jointly used, if required. The color develops are preferably used in an amount of 2-6pts.wt. per 1pts.wt. of the leuco dye, and the color developer of formula (I) is not less than 20wt% based on the total amount of the color developers, preferably, not less than 50wt%. |
