Provided are thermochromic color-memorizing composition and thermochromic color-memorizing microcapsule pigment encapsulating the same, the thermochromic color-memorizing composition including: (a) an electron-donating color-developing organic compound; (b) an electron-accepting compound; and (c) an ester compound represented by the following formula (1) as a reaction medium which controls color reaction between the components (a) and (b): ##STR00001##

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##

[Problems] An object of the present invention is to provide: thermochromic color-memory composition which effectively expresses a property of being capable of interchangeably memorizing and retaining colors and is thus applicable to various fields; and thermochromic memory microcapsule pigment encapsulating the same. [Means for Solution] Provided are thermochromic color-memory composition and thermochromic color-memory microcapsule pigment encapsulating the same, the thermochromic color-memory composition comprising: (a) a component composed of an electron-donating color-developing organic compound; (b) a component composed of an electron-accepting compound; and (c) a reaction medium which comprises an ester compound represented by the following Formula (1) and controls color reaction between the components (a) and (b): ##STR00001##
(wherein, R represents an alkyl group having 4 to 22 carbon atoms, a cycloalkylalkyl group having 5 to 12 carbon atoms, a cycloalkyl group having 4 to 8 carbon atoms or an alkenyl group having 4 to 22 carbon atoms; X represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms or a halogen atom; and n represents 0 or 1).

Provided are thermochromic color-memory composition and thermochromic color-memory microcapsule pigment encapsulating the same, the thermochromic color-memory composition including: (a) a component composed of an electron-donating color-developing organic compound; (b) a component composed of an electron-accepting compound; and (c) a component composed of an ester compound represented by the following Formula (1) as a reaction medium which controls color reaction between the components (a) and (b): ##STR00001##
(wherein, R represents an alkyl group having 3 to 18 carbon atoms or an aliphatic acyl group having 3 to 18 carbon atoms; X represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 or 2 carbon atoms or a halogen atom; Y represents a hydrogen atom or a methyl group; and Z represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 or 2 carbon atoms or a halogen atom).

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.

Provided are thermochromic color-memory composition and thermochromic color-memory microcapsule pigment encapsulating the same, the thermochromic color-memory composition including: (a) a component composed of an electron-donating color-developing organic compound; (b) a component composed of an electron-accepting compound; and (c) a component composed of an ester compound represented by the following Formula (1) as a reaction medium which controls color reaction between the components (a) and (b):

##STR00001##

(wherein, R represents an alkyl group having 3 to 18 carbon atoms or an aliphatic acyl group having 3 to 18 carbon atoms; X represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 or 2 carbon atoms or a halogen atom; Y represents a hydrogen atom or a methyl group; and Z represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 or 2 carbon atoms or a halogen atom).

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 description is given of a heat-sensitive recording material, comprising phenol-free organic color developers, more particularly comprising a color developer mixture comprising phenol-free organic color developers, of a heat-sensitive recording layer and also of a coating composition for producing it, of the use of the heat-sensitive recording material, of the use of an organic color developer of a formula I for improving the resistance of the printed image of a heat-sensitive recording material, and of a method for producing heat-sensitive recording material.