| 摘要 |
PROBLEM TO BE SOLVED: To make color developing properties conspicuously high by setting the arithmetic mean particulate diameter of a microcapsule within a specified range and specifying the grain size distribution of a volume mean particulate diameter and setting the standard deviation of the volume mean particulate diameter within a specified range. SOLUTION: The arithmetic mean particulate diameter of a microcapsule it set within the range of 3-10μm. In the grain size distribution of the volume mean particulate diameter, the ratio of 25% dia. to 50% dia. integrated from the large particulate diameter side is 1.25 or less and the ratio of 75% dia. to 50% dia. is 0.75 or more. In addition, it is preferable to set the standard deviation value of the volume mean particulate diameter within the range of 1-2μm. A color coupler solution is adjusted by dissolving an electron donative color coupler in a hydrophobic solvent, and then is emulsified in water by the action of an emulsion dispersant. It is preferable to use a copolymer of isobutylene-maleic anhydride as an emulsion dispersant. The color coupler solution is emulsion-dispersed by stirring and mixing the color coupler solution with an aqueous emulsion dispersant solution to obtain en emulsion particle. |
