PURPOSE: To obtain a high color concentration without heat escaping from a heat-sensitive head to a supporter by providing a layer composed primarily of fine hollow spherical granules between the supporter and the heat-sensitive coloring layer in a heat-sensitive recording material.
CONSTITUTION: Fine hollow spherical granules (e.g., thermally expanded fine spheres, fine hollow glass powder, or fine hollow aluminosilicate powder) of a grain size of 10μm or less are dispersed in a binder (e.g., starch, casein, polyvinyl acetate, etc.) with water. The dispersion is coated on a supporter and dried to form an under layer, and then a heat-sensitive chromogenic substance and a binder are dissolved or dispersed in water to form a heat-sensitive coloring layer. As the heat-sensitive chromogenic substance, a composition composed of a combination of a compound with binary alcoholic hydroxyl groups, having a melting point of 100W180°C, sulfur, and an inorganic salt or acetate of a metal may be cited preferably.
NAGAMOTO MASANAKA