| 摘要 |
PROBLEM TO BE SOLVED: To improve the image preservation property and the coloring sensitivity by a method wherein a thermosensitive coloring agent contains an isocyanate compound, a colorless or slightly colored electron donating dye precursor and a hydroxyl group-cotaining compound. SOLUTION: This thermosensitive coloring agent contains an isocyanate compound, a colorless or a slightly colored electron donating dye precursor, hydroxyl group-containing compound which is represented by the formula. Then, the isocyanate compound is an isocyanate adduct body of which the melting point is 40 deg.C or higher. In the formula, Y1 indicates either one of -SO2 -, -(S)q -, -0-, -CO-, and -CH(COOY2 )-. (q is 1 or 2. Also, Y2 is an alkyl group.) (m), (n) each are integers of 0-3, and (m+n)>=1 is formed. Also, the hydrogen atom of the benzene ring may be replaced by a fatty compound residue which may have halogen atom or a substituent, or an inorganic compound residue. |
