Abstract: Disclosed is a heat-sensitive recording material comprising a support; a heat-sensitive recording layer formed over the support and containing a color forming material, a color developing material which forms a color on contact with the color forming material and a pigment which is about 80 to about 400 ml/100 g in oil absorption according to JIS K 5101 and about 3 to about 15 .mu.m in average particle size; and an overcoat layer formed over the heat-sensitive recording layer and comprising a binder and a pigment, wherein the pigment is used in an amount of about 0.5 to about 3.0 parts by weight per part by weight of the binder and the coating amount of the overcoat layer is about 0.3 to about 2.0 g/m.sup.2 on dry basis.

Abstract: Disclosed is a heat-sensitive recording material comprising a support and a heat-sensitive recording layer, characterized in that an intermediate layer is formed between the support and the heat-sensitive recording layer wherein the intermediate layer comprises a pigment having an apparent specific gravity of about 0.7 g/cm.sup.3 or less and a polymeric substance having a glass transition temperature of 0.degree. C. or lower as a binder.

Abstract: In order to produce a heat-sensitive record material having high speed recordability without fogging a heat-sensitive record material having a heat-sensitive record layer coated thereon is passed through a nip between a metal roll and an elastic roll of 42.degree. to 69.degree. Shore-D hardness defined by ASTM Standard, D-2240 at a nip pressure enough to obtain a Bekk smoothness of 150 seconds or above on the record layer surface.

Abstract: A heat-sensitive material comprising a support having formed thereon a heat-sensitive recording layer, which has a high whiteness and is suitable for use in high-speed recording, is disclosed. The heat-sensitive recording layer comprises a colorless or pale-colored basic dye and a color developing material that, when heated, reacts with the basic dye to form a color, wherein the heat-sensitive recording layer further comprises at least one heat-fusible material having a melting point in the range of 70.degree. C. to 140.degree. C. and selected from the compounds represented by following formulae (I) to (VI): ##STR1## wherein R.sub.1, R.sub.2, R.sub.5, R.sub.6, and R.sub.7 independently represent a phenyl group, a benzyl group, or a tolyl group, each of which groups may be substituted with a halogen atom; and R.sub.3 and R.sub.

Abstract: A thermal recording paper having formed on a paper support a color generating layer containing a color former and a color developer that contacts the color former to generate a color, wherein the back side of the paper is treated with an inorganic salt, an anionic high molecular weight electrolyte, an electroconductive metallic compound, alumina sol, or silica sol, and has a surface electrical resistivity of not more than 5.times.10.sup.11 ohms at 25.degree. C. and 40% RH.

Abstract: The color developing layer of a heat-sensitive record material comprising(a) electron donating color forming material,(b) acceptor which is reactive with said color forming material to develop a color,(c) a heat fusible material having a melting point with in the range of 60.degree. C. to 200.degree. C., and(d) oil absorptive pigment having an oil absorption within the range of at least 80 ml/100 g said pigment existing in said color developing layer in the form of finely divided particles each having a coating thereon, said coating being formed of said color forming material, said acceptor or said heat fusible material.

Abstract: In a heat-sensitive record material comprising a base sheet and a color developing layer formed thereon, a pigment having an oil absorption within the range of 80 to 800 ml/100 g is additionally included in the color developing layer.

Abstract: In a heat-sensitive record material comprising a base sheet having a color developing layer which includes finely divided particles of chromogenic material and finely divided particles of acceptor, a heat fusible material having a relatively low melting point is included in said finely divided particles of chromogenic material and/or said finely divided particles of acceptor.

Abstract: In a heat-sensitive record material comprising a base sheet and a color developing layer formed thereon, a pigment having an oil absorption within the range of 80 to 800 ml/100 g is additionally included in the color developing layer.