The present invention provides a heat-sensitive recording material which has improved thermal responsiveness and improved stability of the print part and the background in comparison to conventional heat-sensitive recording materials that contain a non-phenolic compound as a color developer. The present invention provides a heat-sensitive recording composition which contains a color former, a color developer and a stabilizer, wherein: N-[2-(3-phenylureido)phenyl]benzenesulfonamide or N-(p-toluenesulfonyl)-N-(3-p-toluenesulfonyloxyphenyl) urea is contained as the color developer, and 1,3-diphenyl urea is contained as the stabilizer.

Disclosed is a heat-sensitive recording material containing at least an undercoat layer and a heat-sensitive recording layer in this order on a support, the undercoat layer containing hollow particles, a binder, and an inorganic pigment I, the heat-sensitive recording layer containing a leuco dye and a developer, wherein (A) the heat-sensitive recording layer contains 5-(N-3-methylphenyl-sulfonamide)-N,N-bis-(3-methylphenyl)-isophthalic acid diamide as a stability improver, or (B) the heat-sensitive recording layer contains 5-(N-3-methylphenyl-sulfonamide)-N,N-bis-(3-methylphenyl)-isophthalic acid diamide as the developer and contains a pigment with an oil absorption of 130 ml/100 g or less as an inorganic pigment II.

The invention relates to a heat-sensitive recording material. A heat-sensitive recording material, comprising a carrier substrate and a heat-sensitive, colour-forming layer that contains at least one colour former and at least one phenol-free colour developer, is characterised in that said at least one colour developer is a compound of formula (I) where Ar.sub.1 and Ar.sub.2 are a phenyl group and/or a C.sub.1-C.sub.4-alkyl substituted phenyl group. The invention also relates to a method for producing this heat-sensitive recording material and to the use, in a heat-sensitive recording material, of the colour developer of formula (I) that is present in said heat-sensitive, colour-forming layer.

##STR00001##

A thermosensitive recording body has at least a thermosensitive recording layer and a topcoat layer formed on a substrate. The substrate consists of a transparent film. At least the thermosensitive recording layer and the topcoat layer includes a diffuse reflection suppressor component that suppresses diffuse reflection of light from particles constituting the thermosensitive recording layer and the topcoat layer.

The present invention provides a heat-sensitive recording material having a high recording density, excellent plasticizer resistance in recorded portions, and excellent resistance to thermal background fogging in high-temperature environments. The heat-sensitive recording material includes a heat-sensitive recording layer containing a specific sulfonamide compound.

A composition for forming a visually discernible color, the use of this composition for producing a heat-sensitive recording material, the corresponding heat-sensitive recording material includes a substrate and this composition, and a process for producing the heat-sensitive recording material.

The purpose of the present invention is to provide a thermosensitive recording medium with an increased gloss in the blank and printed portions, excellent color developing sensitivity and excellent printing run-ability, particularly excellent printing run-ability at high-speed printing. Provided is a thermosensitive recording medium having a thermosensitive recording layer comprising a colorless or pale colored basic leuco dye and an electron accepting color developing agent, an intermediate layer and a gloss layer as an outermost layer in this order on a substrate, wherein the intermediate layer is formed by containing a carboxyl group-containing resin and the gloss layer is formed by containing a long chain alkyl group-containing resin and an emulsion type silicone copolymer resin. The long chain alkyl group-containing resin is preferably an acrylic resin containing long-chain alkyl group(s) and the silicone copolymer resin is preferably a silicone-acryl copolymer resin and/or a silicone-urethane copolymer resin.

A heat-sensitive recording material including a web-shaped substrate having a front side and an opposite reverse side, and at least one heat-sensitive recording layer on either or both of the sides of the web-shaped substrate.

The heat-sensitive recording layer contains a color acceptor having a combination at least consisting of one, two, three or more than three color acceptor (compounds) of formula (1)

##STR00001## where R is alkyl, and of at least one secondary color acceptor comprising lactic acid oligomers conforming to formula (3)

##STR00002##

The present invention provides a heat-sensitive recording material which has improved thermal responsiveness and improved stability of the print part and the background in comparison to conventional heat-sensitive recording materials that contain a non-phenolic compound as a color developer. The present invention provides a heat-sensitive recording composition which contains a color former, a color developer and a stabilizer, wherein: N-[2-(3-phenylureido)phenyl] benzenesulfonamide or N-(p-toluenesulfonyl)-N-(3-p-toluenesulfonyloxyphenyl) urea is contained as the color developer, and 1,3-diphenyl urea is contained as the stabilizer.

A highly marketable reversibly thermochromic composition that provides a black color during color development by using a fluoran derivative having a specific structure as an electron-donating color-developing organic compound, turns colorless during decoloration, and is excellent in contrast between a colored state and a decolored state and a microcapsule pigment encapsulating the same. A reversibly thermochromic composition including: (a) a fluoran derivative having a specific structure as an electron-donating color-developing organic compound; (b) an electron-accepting compound; and (c) a reaction medium which reversibly induces an electron transfer reaction between the component (a) and the component (b) in a specific temperature range, and a reversibly thermochromic microcapsule pigment encapsulating the same.