| 摘要 |
PROBLEM TO BE SOLVED: To obtain a heat-sensitive recording material having high sensitivity and hardly causing blackening in unclored part in moist heat and excellent in image storing property. SOLUTION: In a heat-sensitive recording material having a heat-sensitive coloring layer normally containing colorless or pale coloring compound and a color-developing compound capable of coloring the coloring compound by heating, the heat-sensitive recording material contains crystal of a 3,3'-diaryl-4,4'- dihydroxydiphenyl sulfone which is a crystal form having >=149 deg.C DSC (Te) and characterized by X ray diffraction figure having peaks at least at 7.2 deg. and 22.0 deg. diffraction angle (2θ) in X ray powder diffraction method by Cu-Kα beam as the color developing compound. |
