| 摘要 |
PROBLEM TO BE SOLVED: To provide a multicolor thermal recording material which shows outstanding shelf life and developes a vivid red color at a low temperature. SOLUTION: This multicolor thermal recording material consists of a support, two or more different types of dye precursor which are formed on the support and develop colors of different tones from each other, and a thermal color developing layer containing a color developing compound which causes the precursors to develop colors through a chemical reaction with the precursors under heat. The thermal color developing layer contains at least, one type of red color developing dye precursor selected between 3-diethylamino-7- phenoxyfruoran and 3-(N-ethyl-N-isoamylamino)-7-phenoxyfruoran. In addition, a solution containing a polyvalent isocyanate compound as a solvent and the dye precursor, as a dissolved substance, which develops a color of different tone from the red color developing dye precursor, is emulsified and dispersed in water, and then the polymerization reaction of the polyvalent isocyanate compound is accelerated. Consequently, a composite microparticle is obtained and this obtained composite microparticle is added to the thermal color developing layer. |
