JP2005059267A - Thermal recording material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal recording material with high thermal stability and excellent in preservility in raw state and in storing properties in a dark place. <P>SOLUTION: The thermal recording material comprises a diazonium salt and a coupler on a substrate, wherein the diazonium salt is at least one compound selected from compounds of general formulae (1) and (2), and a thermal recording layer furthermore comprises a molten salt. In the general formulae (1) and (2), R<SP>1</SP>-R<SP>2</SP>are each an alkyl group, an aryl group or an aralkyl group; R<SP>3</SP>-R<SP>6</SP>are each a hydrogen atom or a monovalent substituent, but at least one of R<SP>3</SP>-R<SP>6</SP>are -N<SB>2</SB><SP>+</SP>X<SP>-</SP>; R<SP>7</SP>-R<SP>8</SP>are each an alkyl group or an aryl group; R<SP>9</SP>-R<SP>12</SP>are each a hydrogen atom or a monovalent substituent, but at least one of R<SP>9</SP>-R<SP>12</SP>are -N<SB>2</SB><SP>+</SP>X<SP>-</SP>; and X<SP>-</SP>is a counter anion. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a heat-sensitive recording material comprising a diazonium salt and a coupler as color forming components.

  Thermal recording materials that record images by supplying heat with a thermal head or the like are widely used because they are relatively inexpensive, their recording devices are simple and reliable, and no maintenance is required. Under such circumstances, in recent years, there has been a great demand for higher performance such as higher image quality and improved storage stability, and research on color density, image quality, storability, and the like of thermosensitive recording materials has been conducted intensively.

  Many heat-sensitive recording materials using a diazonium salt as a color forming component have been developed, and the color density, image quality and storage stability have been improved. A diazo color-forming thermosensitive recording material containing a diazonium salt encapsulates the diazonium salt in a microcapsule and forms an image by thermal printing, and then thermally decomposes and fixes the diazonium salt in the unprinted area with light. As a result, storability (image storability) as a recording material can be greatly improved.

  In addition, the density of the image recorded after the storage time may be lower than the density of the image immediately after printing. The density ratio of the image before and after storage is called raw storage, and improving the raw storage is one of the major issues.

  Further, the dye produced in the heat-sensitive recording layer may be gradually decomposed by an external stimulus such as light, heat and oxygen, and the optical density may be lowered. Further, the optical density may be lowered by the phase change of the dye molecule aggregate or the refractive index change of the mixture in the recording layer. In this way, the decrease in optical density occurs even when the image is stored with the light blocked, and when the recorded image is stored with the light blocked, the density ratio before and after the storage is determined as the dark storage property of the image. That's it. In heat-sensitive recording materials, in particular, improving the dark storability of images is also a major issue.

  In order to solve these problems, heat-sensitive recording materials using specific diazonium salts have been proposed. However, the thermal stability is not always sufficient, resulting in a decrease in raw storage and a decrease in background whiteness due to diazo decomposition products. (For example, refer to Patent Document 1).

  On the other hand, ionic liquids have attracted attention in recent years. An ionic liquid has a feature that it has almost no vapor pressure, a relatively low viscosity, and high heat resistance. As a heat-sensitive recording material using an ionic liquid, for example, a silver salt photothermographic color photosensitive material containing an ionic liquid as a constituent element is known (for example, see Patent Documents 2 and 3).

However, even with these heat-sensitive recording materials, there is a problem that deterioration of dark storage stability cannot be sufficiently suppressed while having sufficient raw storage properties, and improvement of raw storage properties and dark storage properties is achieved. Development of such a heat-sensitive recording material is desired.
JP 2002-326457 A US Pat. No. 6,531,270 US Pat. No. 6,531,273

An object of the present invention is to provide a heat-sensitive recording material that has high thermal stability and excellent raw storage properties and suppresses a decrease in density during storage in a dark place.

  <1> A thermosensitive recording material having a thermosensitive recording layer containing a diazonium salt and a coupler that develops color by reacting with the diazonium salt on a support, wherein the diazonium salt is represented by the following general formula (1). The heat-sensitive recording layer is a heat-sensitive recording material characterized in that it is at least one selected from the compounds represented by formula (2) and the compound represented by the general formula (2), and the heat-sensitive recording layer further contains a molten salt.

〔一般式（１）中、Ｒ¹およびＲ²は、それぞれ独立して、アルキル基、アリール基またはアラルキル基を表す。Ｒ³，Ｒ⁴，Ｒ⁵およびＲ⁶は、それぞれ独立して、水素原子、または一価の置換基を表す。但し、Ｒ³，Ｒ⁴，Ｒ⁵およびＲ⁶のうち少なくとも一つは、−Ｎ₂ ⁺Ｘ^-を表す。Ｘ^-は対アニオンを表す。〕

[In General Formula (1), R ¹ and R ² each independently represents an alkyl group, an aryl group, or an aralkyl group. R ³ , R ⁴ , R ⁵ and R ⁶ each independently represents a hydrogen atom or a monovalent substituent. However, at least one of R ³ , R ⁴ , R ⁵ and R ⁶ represents —N ₂ ⁺ X ⁻ . X ⁻ represents a counter anion. ]

〔一般式（２）中、Ｒ⁷およびＲ⁸は、それぞれ独立して、アルキル基またはアリール基を表す。Ｒ⁹，Ｒ¹⁰，Ｒ¹¹およびＲ¹²は、それぞれ独立して、水素原子、または一価の置換基を表す。但し、Ｒ⁹，Ｒ¹⁰，Ｒ¹¹およびＲ¹²のうち少なくとも一つは、−Ｎ₂ ⁺Ｘ^-を表す。Ｘ^-は対アニオンを表す。〕

[In General Formula (2), R ⁷ and R ⁸ each independently represents an alkyl group or an aryl group. R ⁹ , R ¹⁰ , R ¹¹ and R ¹² each independently represents a hydrogen atom or a monovalent substituent. However, at least one of R ⁹ , R ¹⁰ , R ¹¹ and R ¹² represents —N ₂ ⁺ X ⁻ . X ⁻ represents a counter anion. ]

  <2> The molten salt is at least one selected from an imidazolium salt, a pyrazolium salt, a pyridinium salt, a pyrimidinium salt, a pyrazinium salt, a thiazolium salt, an oxazolium salt, a tetraalkylammonium salt, and a tetraalkylphosphonium salt. <1> The heat-sensitive recording material as described above.

  <3> The heat-sensitive recording material according to <1>, wherein the molten salt is at least one selected from compounds represented by the following general formulas (3) to (5).

〔一般式（３）中、Ｒ²¹およびＲ²²は、それぞれ独立して総炭素数１〜３０のアルキル基、総炭素数７〜４０のアラルキル基を表す。Ｒ²³，Ｒ²⁴およびＲ²⁵は、それぞれ独立して、水素原子、ハロゲン原子、総炭素数１〜１０のアルキル基を表す。Ｒ²¹，Ｒ²²，Ｒ²³，Ｒ²⁴およびＲ²⁵で表されるアルキル基およびアラルキル基は、ハロゲン原子、アルコキシ基、アリールオキシ基、アルコキシカルボニル基、またはアシルオキシ基で置換されていてもよい。Ｙ^-は対アニオンを表す。〕

[In General Formula (3), R ²¹ and R ²² each independently represent an alkyl group having 1 to 30 carbon atoms and an aralkyl group having 7 to 40 carbon atoms. R ²³ , R ²⁴ and R ²⁵ each independently represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 10 carbon atoms. The alkyl group and aralkyl group represented by R ²¹ , R ²² , R ²³ , R ²⁴ and R ²⁵ may be substituted with a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group or an acyloxy group. Y ⁻ represents a counter anion. ]

〔一般式（４）中、Ｒ²⁶は総炭素数１〜３０のアルキル基または総炭素数７〜４０のアラルキル基を表す。Ｒ²⁷，Ｒ²⁸，Ｒ²⁹，Ｒ³⁰およびＲ³¹はそれぞれ独立して、水素原子、ハロゲン原子、総炭素数１〜１０のアルキル基を表す。Ｒ²⁶，Ｒ²⁷，Ｒ²⁸，Ｒ²⁹，Ｒ³⁰およびＲ³¹で表されるアルキル基およびアラルキル基は、ハロゲン原子、アルコキシ基、アリールオキシ基、アルコキシカルボニル基、またはアシルオキシ基で置換されていてもよい。Ｙ^-は対アニオンを表す。〕

[In General Formula (4), R ²⁶ represents an alkyl group having 1 to 30 carbon atoms or an aralkyl group having 7 to 40 carbon atoms in total. R ²⁷ , R ²⁸ , R ²⁹ , R ³⁰ and R ³¹ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms. The alkyl group and aralkyl group represented by R ²⁶ , R ²⁷ , R ²⁸ , R ²⁹ , R ³⁰ and R ³¹ are substituted with a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group or an acyloxy group. Also good. Y ⁻ represents a counter anion. ]

〔一般式（５）中、Ｒ³²，Ｒ³³，Ｒ³⁴およびＲ³⁵は、それぞれ独立して総炭素数１〜３０のアルキル基または総炭素数７〜４０のアラルキル基を表す。Ｒ³²，Ｒ³³，Ｒ³⁴およびＲ³⁵は、ハロゲン原子、アルコキシ基、アリールオキシ基、アルコキシカルボニル基、またはアシルオキシ基で置換されていてもよい。Ｚは、窒素原子またはリン原子を表す。Ｙ^-は対アニオンを表す。〕

[In General Formula (5), R ³² , R ³³ , R ³⁴ and R ³⁵ each independently represents an alkyl group having 1 to 30 carbon atoms or an aralkyl group having 7 to 40 carbon atoms. R ³² , R ³³ , R ³⁴ and R ³⁵ may be substituted with a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group or an acyloxy group. Z represents a nitrogen atom or a phosphorus atom. Y ⁻ represents a counter anion. ]

  <4> The thermosensitive recording material according to <1> to <3>, wherein the diazonium salt and the molten salt are encapsulated in the same microcapsule.

  <5> The heat-sensitive recording material according to the above <1> to <4>, wherein the microcapsule comprises polyurethane and / or polyurea.

  According to the present invention, it is possible to provide a heat-sensitive recording material having high thermal stability and excellent raw storability and excellent storability in a dark place.

《Thermal recording material》
The heat-sensitive recording material of the present invention has on a support a heat-sensitive recording layer containing a diazonium salt and a coupler that develops color by reacting with the diazonium salt, and the diazonium salt is represented by the following general formula (1). And at least one selected from the compounds represented by formula (2), and the heat-sensitive recording layer further contains a molten salt.

〔一般式（１）中、Ｒ¹およびＲ²は、それぞれ独立して、アルキル基、アリール基またはアラルキル基を表す。Ｒ³，Ｒ⁴，Ｒ⁵およびＲ⁶は、それぞれ独立して、水素原子、または一価の置換基を表す。但し、Ｒ³，Ｒ⁴，Ｒ⁵およびＲ⁶のうち少なくとも一つは、−Ｎ₂ ⁺Ｘ^-を表す。Ｘ^-は対アニオンを表す。〕

[In General Formula (1), R ¹ and R ² each independently represents an alkyl group, an aryl group, or an aralkyl group. R ³ , R ⁴ , R ⁵ and R ⁶ each independently represents a hydrogen atom or a monovalent substituent. However, at least one of R ³ , R ⁴ , R ⁵ and R ⁶ represents —N ₂ ⁺ X ⁻ . X ⁻ represents a counter anion. ]

〔一般式（２）中、Ｒ⁷およびＲ⁸は、それぞれ独立して、アルキル基またはアリール基を表す。Ｒ⁹，Ｒ¹⁰，Ｒ¹¹およびＲ¹²は、それぞれ独立して、水素原子、または一価の置換基を表す。但し、Ｒ⁹，Ｒ¹⁰，Ｒ¹¹およびＲ¹²のうち少なくとも一つは、−Ｎ₂ ⁺Ｘ^-を表す。Ｘ^-は対アニオンを表す。〕

[In General Formula (2), R ⁷ and R ⁸ each independently represents an alkyl group or an aryl group. R ⁹ , R ¹⁰ , R ¹¹ and R ¹² each independently represents a hydrogen atom or a monovalent substituent. However, at least one of R ⁹ , R ¹⁰ , R ¹¹ and R ¹² represents —N ₂ ⁺ X ⁻ . X ⁻ represents a counter anion. ]

  The heat-sensitive recording material of the present invention comprises at least one selected from the compound represented by the above general formula (1) and the compound represented by the general formula (2) as a diazonium salt (hereinafter referred to as “diazonium salt in the present invention”). ) And a molten salt can be used together to achieve both excellent raw and dark storability.

  The heat-sensitive recording material of the present invention comprises at least one heat-sensitive recording layer on a support, and may further have other layers such as a protective layer, a light transmittance adjusting layer, and an intermediate layer.

(Thermosensitive recording layer)
The heat-sensitive recording layer in the present invention comprises at least the diazonium salt in the present invention, a coupler that reacts with the diazonium salt to cause color development, and the molten salt in the present invention, and may further include other components.

-Diazonium salt-
The diazonium salt in the present invention has low thermal decomposability and can improve the thermal stability of the produced thermosensitive recording material, that is, the raw storage stability, and stably forms a high density image without depending on environmental conditions. can do. The diazonium salt compound in the present invention is a compound represented by at least one of the following general formulas (1) and (2).

In the general formula (1), R ¹ and R ² each independently represents an alkyl group, an aryl group, or an aralkyl group. The alkyl group, aryl group and aralkyl group may be unsubstituted or substituted, and the substituents in the case of being substituted include a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group and an acyloxy group. , An amide group and a carbamoyl group are preferred.

Specifically, the alkyl group represented by R ¹ and R ² is preferably an alkyl group having 1 to 30 carbon atoms, and more preferably an alkyl group having 1 to 20 carbon atoms. For example, methyl group, ethyl group, isopropyl group, n-butyl group, t-butyl group, isopentyl group, 3-pentyl group, t-amyl group, n-hexyl group, cyclohexyl group, n-octyl group, t-octyl Group, 2-ethylhexyl group, isononyl group, n-dodecyl group, hexadecyl group, 3,5,5-trimethylhexyl group, octadecyl group, benzyl group, (4-ethoxyphenyl) methyl group, N, N-diethylcarbamoylmethyl Group, N, N-dibutylcarbamoylmethyl group, 1- (N, N-dibutylcarbamoyl) ethyl group and 2-methoxyethyloxy group are preferable, butyl group, hexyl group, benzyl group, N, N-dibutylcarbamoylmethyl group 1- (N, N-dibutylcarbamoyl) ethyl group is particularly preferred.

  As the aryl group, an aryl group having 6 to 40 carbon atoms is preferable, and an aryl group having 6 to 20 carbon atoms is more preferable. Specifically, phenyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-phenylphenoxy group, 4-chlorophenyl group, 2-methoxyphenyl group, p-methoxyphenyl, 3- Ethoxyphenyl group, 4-butoxyphenyl group, 2,4-diethoxyphenyl group, 2,5-dibutoxyphenyl group, 4-phenoxyphenyl group, naphthyl group, 4-dibutylcarbamoylphenyl group, 4-dibutylsulfamoyl A phenyl group, p- (2-ethylhexyloxy) phenyl group, 2,5-dimethylphenyl group, 2,6-dimethoxyphenyl, and 2,4-di-t-amylphenyl group are preferable, phenyl group, 2-methyl Phenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-chlorophenyl group, 2-methoxyphenyl , 3-ethoxyphenyl group, 4-butoxyphenyl group are particularly preferable.

  As the aralkyl group, an aralkyl group having 7 to 30 carbon atoms is preferable, and an aralkyl group having 7 to 20 carbon atoms is more preferable. Specific examples include benzyl group, 4-methoxybenzyl group, 2-methylbenzyl group, phenethyl group, 4-chlorobenzyl group, 2,4-dichlorobenzyl group, and the like. Of these, a benzyl group, a 4-chlorobenzyl group, and a 2,4-dichlorobenzyl group are preferable.

In the general formula (1), R ³ , R ⁴ , R ⁵ and R ⁶ each independently represents a hydrogen atom or a monovalent substituent. Examples of the monovalent substituent include a halogen atom, alkyl group, aryl group, alkoxy group, aryloxy group, alkylthio group, arylthio group, alkoxycarbonyl group, acylamino group, carbamoyl group, cyano group, alkylsulfonyl group, arylsulfonyl Group, sulfamoyl group and diazonio group are preferable, and more preferably a halogen atom, alkyl group, aryl group, alkoxy group, aryloxy group, alkylthio group, arylthio group, acylamino group, sulfonylamino group or diazonio group, At least one of R ³ , R ⁴ , R ⁵ and R ⁶ represents a diazonio group (—N ₂ ⁺ X ⁻ ). Moreover, it is preferable that at least one of R ³ , R ⁴ , R ⁵ and R ⁶ represents an alkoxy group or an aryloxy group.

The alkyl group or aryl group represented by R ³ , R ⁴ , R ⁵ and R ⁶ has the same meaning as the alkyl group or aryl group represented by R ¹ , and preferred specific examples are also the same.

The halogen atom represented by R ³ , R ⁴ , R ⁵ and R ⁶ is preferably a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, more preferably a fluorine atom or a chlorine atom.

The alkoxy group represented by R ³ , R ⁴ , R ⁵ and R ⁶ may be unsubstituted or substituted, and is preferably an alkoxy group having 1 to 30 carbon atoms in total, having 1 carbon atom in total. More preferred are ˜20 alkoxy groups. Specifically, for example, methoxy group, ethoxy group, propoxy group, butoxy group, hexyloxy group, 2-ethylhexyloxy group, 3,5,5-trimethylhexyloxy group, octyloxy group, decyloxy group, 2-phenoxy An ethoxy group, 2- (3,5-di-t-butylphenoxy) ethoxy group, dibutylcarbamoylmethoxy group, hexadecyloxy group, and octadecyloxy group are preferable, methoxy group, ethoxy group, butoxy group, hexyloxy group, 2 -Ethylhexyloxy group, 3,5,5-trimethylhexyloxy group, 2-phenoxyethoxy group, and dibutylcarbamoylmethoxy group are more preferable.

The aryloxy group represented by R ³ , R ⁴ , R ⁵ and R ⁶ may be unsubstituted or substituted, and is preferably an aryloxy group having 6 to 30 carbon atoms in total. An aryloxy group having a number of 6 to 20 is more preferable. Specifically, for example, phenoxy group, tolyloxy group, 4-chlorophenyloxy group, 4-acetamidophenyloxy group, 2-butoxyphenyloxy group, 2-benzoylaminophenyloxy group, 2,5-dimethoxy-4-nitro Phenyloxy group and 3-octyloxyphenyloxy group are preferable, phenoxy group, tolyloxy group, 4-chlorophenyloxy group, 4-acetamidophenyloxy group, 2-butoxyphenyloxy group, 2,5-dimethoxy-4-nitrophenyl An oxy group is more preferable.

The alkylthio group represented by R ³ , R ⁴ , R ⁵ and R ⁶ may be unsubstituted or substituted, and is preferably an alkylthio group having 1 to 30 carbon atoms in total, having 1 carbon atom in total. More preferred are ˜20 alkylthio groups. Specifically, for example, methylthio group, ethylthio group, butylthio group, hexylthio group, 2-ethylhexylthio group, 3,5,5-trimethylhexylthio group, octylthio group, decylthio group, 2-phenoxyethylthio group, 2 -(3,5-di-t-butylphenoxy) ethylthio group, dibutylcarbamoylmethylthio group, hexadecylthio group, octadecylthio group are preferred, methylthio group, ethylthio group, butylthio group, hexylthio group, 2-ethylhexylthio group, 3, More preferred are 5,5-trimethylhexylthio group, 2-phenoxyethylthio group, and dibutylcarbamoylmethylthio group.

The arylthio group represented by R ³ , R ⁴ , R ⁵ and R ⁶ may be unsubstituted or substituted, and is preferably an arylthio group having 6 to 30 carbon atoms in total, having 6 carbon atoms in total. More preferred are ˜20 arylthio groups. Specifically, for example, phenylthio group, tolylthio group, 4-chlorophenylthio group, 4-acetamidophenylthio group, 2-butoxyphenylthio group, 2-benzoylaminophenylthio group, 2,5-dimethoxy-4-nitro Phenylthio group and 3-octyloxyphenylthio group are preferable, phenylthio group, tolylthio group, 4-chlorophenylthio group, 4-acetamidophenylthio group, 2-butoxyphenylthio group, 2,5-dimethoxy-4-nitrophenyl More preferred is a thio group.

The acylamino group represented by R ³ , R ⁴ , R ⁵ and R ⁶ may be unsubstituted or substituted, and is preferably an acylamino group having 1 to 30 carbon atoms in total, having 1 carbon atom in total. More preferred is an acylamino group of ˜20. Specifically, for example, formylamino group, acetylamino group, butyrylamino group, lauroylamino group, benzoylamino group, toluoylamino group, phenoxyacetyl group, (4-methoxyphenoxy) acetyl group, 2 ′, 4 ′ -Dichlorobenzoylamino group, 2 ', 4'-di-t-amylbenzoylamino group, acetylmethylamino group, benzoylmethylamino group, acetylbenzylamino group are preferred, acetylamino group, butyrylamino group, benzoylamino group, toluene More preferred are an oilamino group, a phenoxyacetyl group, a 2 ′, 4′-di-t-amylbenzoylamino group, an acetylmethylamino group, a benzoylmethylamino group, and an acetylbenzylamino group.

The alkoxycarbonyl group represented by R ³ , R ⁴ , R ⁵ and R ⁶ may be unsubstituted or substituted, and is preferably an alkoxycarbonyl group having 2 to 30 carbon atoms in total. A C2-C20 alkoxycarbonyl group is more preferable. Specifically, for example, methoxycarbonyl group, ethoxycarbonyl group, butoxycarbonyl group, phenoxycarbonyl group, (2-ethylhexyl) oxycarbonyl group, hexyloxycarbonyl group, octyloxycarbonyl group, (4-methoxyphenyl) oxycarbonyl Group is preferable, and a methoxycarbonyl group, an ethoxycarbonyl group, a butoxycarbonyl group, and a phenoxycarbonyl group are particularly preferable.

The carbamoyl group represented by R ³ , R ⁴ , R ⁵ and R ⁶ may be unsubstituted or substituted, and is preferably a carbamoyl group having 1 to 30 carbon atoms in total, having a total carbon number of 1 More preferred are -20 carbamoyl groups. Specifically, for example, carbamoyl group, N-phenylcarbamoyl group, N-butylcarbamoyl group, N, N-dimethylcarbamoyl group, N, N-diethylcarbamoyl group, N, N-dibutylcarbamoyl group, N, N- Dihexylcarbamoyl group, N, N-diphenylcarbamoyl group, N-methyl-N-phenylcarbamoyl group, N-ethyl-N-phenylcarbamoyl group, N-methyl-N-tolylcarbamoyl group, morpholinocarbonyl group, piperidinocarbonyl group N, N-bis (2-methoxyethyl) carbamoyl group is preferable, and N, N-diethylcarbamoyl group, N, N-dibutylcarbamoyl group, and N-methyl-N-phenylcarbamoyl group are particularly preferable.

The alkylsulfonyl group represented by R ³ , R ⁴ , R ⁵ and R ⁶ may be unsubstituted or substituted, and is preferably an alkylsulfonyl group having 1 to 30 carbon atoms in total. A C1-C20 alkylsulfonyl group is more preferable. Specifically, for example, a methylsulfonyl group, an ethylsulfonyl group, a butylsulfonyl group, a hexylsulfonyl group, and a benzylsulfonyl group are preferable, and a methylsulfonyl group and a benzylsulfonyl group are particularly preferable.

The arylsulfonyl group represented by R ³ , R ⁴ , R ⁵ and R ⁶ may be unsubstituted or substituted, and is preferably an arylsulfonyl group having 6 to 30 carbon atoms in total. An arylsulfonyl group having a number of 6 to 20 is more preferable. Specifically, for example, phenylsulfonyl group, 4-methylphenylsulfonyl group, naphthylsulfonyl group, 4-methoxysulfonyl group, 4-chlorophenylsulfonyl group are preferable, methylsulfonyl group, phenylsulfonyl group, 4-methylphenylsulfonyl group. Is particularly preferred.

The sulfamoyl group represented by R ³ , R ⁴ , R ⁵ and R ⁶ may be unsubstituted or substituted, and is preferably a sulfamoyl group having 1 to 30 carbon atoms in total. More preferred are ˜20 sulfamoyl groups. Specifically, for example, sulfamoyl group, N-phenylsulfamoyl group, N, N-dimethylsulfamoyl group, N, N-diethylsulfamoyl group, N, N-dibutylsulfamoyl group, N, N-dihexylsulfamoyl group, N, N-diphenylsulfamoyl group, N-methyl-N-phenylsulfamoyl group, N-ethyl-N-phenylsulfamoyl group, N-methyl-N-tolylsulfur group Famoyl group, morpholinosulfonyl group, piperidinosulfonyl group, N, N-bis (2-methoxyethyl) sulfonyl group are preferable, sulfamoyl group, N-phenylsulfamoyl group, N, N-dibutylsulfamoyl group N, N-diphenylsulfamoyl group and N-methyl-N-phenylsulfamoyl group are particularly preferable.

The diazonio group represented by R ³ , R ⁴ , R ⁵ and R ^{6 can} be represented by —N ₂ ⁺ X ⁻ , and X ⁻ represents a counter anion. However, at least one of R ³ , R ⁴ , R ⁵ and R ⁶ represents a diazonio group (—N ₂ ⁺ X ⁻ ).
X ⁻ represents a counter anion. The counter anion may be either an inorganic anion or an organic anion.
As the inorganic anion, for example, hexafluorophosphate ion, borohydrofluoric acid ion, chloride ion, and sulfuric acid ion are preferable, and among them, hexafluorophosphate ion and borohydrofluoric acid ion are particularly preferable. Further, as the organic anion, for example, polyfluoroalkylcarboxylate ion, polyfluoroalkylsulfonate ion, aromatic carboxylate ion, aromatic sulfonate ion, and ions described in Japanese Patent Application No. 2002-108919 are preferable, Among these, polyfluoroalkylcarboxylate ions, polyfluoroalkylsulfonate ions, and ions described in Japanese Patent Application No. 2002-108919 are particularly preferable.

  Furthermore, the diazonium salt in the present invention is particularly preferably a compound represented by the following general formula (6).

〔一般式（６）中、Ｒ¹³，Ｒ¹⁴およびＲ¹⁶は、それぞれ独立して、総炭素数１〜２０のアルキル基、または総炭素数６〜３０のアリール基、または総炭素数７〜３０のアラルキル基を表し、ハロゲン原子、アルコキシ基、アリールオキシ基、アルコキシカルボニル基、アシルオキシ基、アミド基またはカルバモイル基が置換していてもよい。Ｒ¹⁵およびＲ¹⁷は、それぞれ独立して、水素原子、総炭素数１〜１０アルキル基またはハロゲン原子を表す。Ｘ^-は対アニオンを表す。〕

[In General Formula (6), R ¹³ , R ¹⁴ and R ¹⁶ are each independently an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, or 7 to 7 carbon atoms. 30 represents an aralkyl group, which may be substituted with a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an amide group or a carbamoyl group. R ¹⁵ and R ¹⁷ each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a halogen atom. X ⁻ represents a counter anion. ]

In General Formula (6), R ¹³ , R ^14, and R ¹⁶ are each independently an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, or 7 to 30 carbon atoms. An aralkyl group of which may be substituted by a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an amide group or a carbamoyl group.

  The alkyl group having 1 to 20 carbon atoms is preferably an alkyl group having 1 to 16 carbon atoms. Specifically, methyl group, ethyl group, butyl group, hexyl group, octyl group, 2-ethylhexyl group, 3,5,5-trimethylhexyl group, dodecyl group, octadecyl group, (4-ethoxyphenyl) methyl group, Preferable examples include N, N-diethylcarbamoylmethyl group, N, N-dibutylcarbamoylmethyl group, 1- (N, N-dibutylcarbamoyl) ethyl group, 2-methoxyethyloxy group and the like. Of these, a butyl group, hexyl group, N, N-diethylcarbamoylmethyl group, N, N-dibutylcarbamoylmethyl group, and 1- (N, N-dibutylcarbamoyl) ethyl group are particularly preferable.

  The aryl group having 6 to 30 carbon atoms is preferably an aryl group having 6 to 20 carbon atoms. Specifically, phenyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-phenylphenoxy group, 4-chlorophenyl group, 2-methoxyphenyl group, 3-ethoxyphenyl group, 4 -Butoxyphenyl group, 2,4-diethoxyphenyl group, 2,5-dibutoxyphenyl group, 4-phenoxyphenyl group, naphthyl group, 4-dibutylcarbamoylphenyl group, 4-dibutylsulfamoylphenyl group, 2, A 4,6-tris (trifluoromethyl) phenyl group and the like are preferable. Of these, a phenyl group, a 2-methylphenyl group, a 3-methylphenyl group, a 4-methylphenyl group, a 4-chlorophenyl group, a 2-methoxyphenyl group, a 3-ethoxyphenyl group, and a 4-butoxyphenyl group are particularly preferable.

  The aralkyl group having 7 to 30 carbon atoms is more preferably an aralkyl group having 7 to 20 carbon atoms. Specific examples include benzyl group, 4-methoxybenzyl group, 2-methylbenzyl group, phenethyl group, 4-chlorobenzyl group, 2,4-dichlorobenzyl group, and the like. Of these, a benzyl group, a 4-chlorobenzyl group, and a 2,4-dichlorobenzyl group are preferable.

In General Formula (6), R ¹⁵ and R ¹⁷ each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a halogen atom.
The alkyl group having 1 to 10 carbon atoms is preferably an alkyl group having 1 to 8 carbon atoms, and specifically, methyl group, ethyl group, butyl group, hexyl group, octyl group, 2-ethylhexyl group. , (4-ethoxyphenyl) methyl group, and the like. Of these, a methyl group, an ethyl group, and a butyl group are particularly preferable.

The halogen atom represented by R ¹⁵ or R ¹⁷ is preferably a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, and more preferably a fluorine atom or a chlorine atom.

X ⁻ represents a counter anion. The general formula X ^- is in the general formula (1) X ^- are those same as the.

In the general formula (2), R ⁷ and R ⁸ each independently represents an alkyl group or an aryl group. The alkyl group, aryl group and aralkyl group may be unsubstituted or substituted, and the substituents when substituted are a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group. , An amide group and a carbamoyl group are preferred.

Specifically, the alkyl group represented by R ⁷ and R ⁸ is preferably an alkyl group having 1 to 30 carbon atoms, and more preferably an alkyl group having 1 to 20 carbon atoms. For example, methyl group, ethyl group, n-propyl group, isopropyl group, normal butyl group, isobutyl group, t-butyl group, pentyl group, cyclopentyl group, isopentyl group, 3-pentyl group, t-amyl group, n-hexyl Group, cyclohexyl group, heptyl group, n-octyl group, t-octyl, 2-ethylhexyl group, decyl group, n-dodecyl group, octadecyl group, 2-hydroxyethyl group, 2-benzoyloxyethyl group, 2- (4 -Butoxyphenoxy) ethyl, benzyl, allyl, methoxyethyl, ethoxyethyl, dibutylaminocarbonylmethyl, isononyl, hexadecyl are preferred.
Among these, a C1-C18 alkyl group is preferable, and a methyl group, an ethyl group, a normal propyl group, a normal butyl group, an isobutyl group, a decyl group, an octyl group, a benzyl group, and a methoxyethyl group are particularly preferable.

  As the aryl group, an aryl group having 6 to 40 carbon atoms is preferable, and an aryl group having 6 to 20 carbon atoms is more preferable. Specifically, phenyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-phenylphenoxy group, 4-chlorophenyl group, p-methoxyphenyl group, p- (2-ethylhexyl). Siloxy) phenyl group, 2-methoxyphenyl group, 3-ethoxyphenyl group, 4-butoxyphenyl group, 2,4-diethoxyphenyl group, 2,5-dibutoxyphenyl group, 4-phenoxyphenyl group, naphthyl group, Preferred examples include 4-dibutylcarbamoylphenyl group, 4-dibutylsulfamoylphenyl group, 2,5-dimethylphenyl group, 2,6-dimethoxyphenyl group, 2,4-di-t-amylphenyl group and the like. Of these, a phenyl group, a 2-methylphenyl group, a 3-methylphenyl group, a 4-methylphenyl group, a 4-chlorophenyl group, a 2-methoxyphenyl group, a 3-ethoxyphenyl group, and a 4-butoxyphenyl group are particularly preferable.

In the general formula (2), R ⁹ , R ¹⁰ , R ¹¹ and R ¹² each independently represent a hydrogen atom or a monovalent substituent. Examples of the monovalent substituent include a halogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an alkylsulfonyl group, an arylsulfonyl group, and a diazonio group.

The halogen atom represented by R ⁹ , R ¹⁰ , R ¹¹ and R ¹² is preferably a chlorine atom, a bromine atom or an iodine atom.

The alkyl group represented by R ⁹ , R ¹⁰ , R ¹¹ and R ¹² may be unsubstituted or may have a substituent. Examples of the substituent that can be introduced into the alkyl group include a phenyl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, a cyano group, a carboxylic acid group, and a sulfonic acid group. And heterocyclic groups are preferred.
Specifically, the alkyl group represented by R ⁹ , R ¹⁰ , R ¹¹ and R ¹² is preferably an alkyl group having 1 to 30 carbon atoms in total, for example, a methyl group, an ethyl group, a normal propyl group, isopropyl Group, normal butyl group, isobutyl group, pentyl group, cyclopentyl group, hexyl group, cyclohexyl group, heptyl group, octyl group, 2-ethylhexyl group, decyl group, dodecyl group, octadecyl group, 2-hydroxyethyl group, 2-benzoyl group Preferable examples include oxyethyl group, 2- (4-butoxyphenoxy) ethyl group, benzyl group, allyl group, methoxyethyl group, ethoxyethyl, and dibutylaminocarbonylmethyl group.
Among these, a C1-C20 alkyl group is preferable and a methyl group, an ethyl group, a normal propyl group, a normal butyl group, a decyl group, a benzyl group, and a methoxyethyl group are especially preferable.

The aryl group represented by R ⁹ , R ¹⁰ , R ¹¹ and R ¹² may be unsubstituted or may have a substituent. Examples of the substituent that can be introduced into the aryl group include a phenyl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, a cyano group, a carboxylic acid group, and a sulfonic acid group. And heterocyclic groups are preferred.
Specifically, the aryl group represented by R ⁹ , R ¹⁰ , R ¹¹ and R ¹² is preferably an aryl group having 6 to 30 carbon atoms in total, such as a phenyl group, a 4-chlorophenyl group, and a 4-methylphenyl group. 4-butoxyphenyl group is preferable.

The alkoxy group represented by R ⁹ , R ¹⁰ , R ¹¹ and R ¹² may be unsubstituted or may have a substituent. Examples of the substituent that can be introduced into the alkoxy group include a phenyl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, a cyano group, a carboxylic acid group, and a sulfonic acid group. And heterocyclic groups are preferred.
Specifically, the alkoxy group represented by R ⁹ , R ¹⁰ , R ¹¹ and R ¹² is preferably an alkoxy group having 1 to 30 carbon atoms in total, for example, methoxy group, ethoxy group, propyloxy group, butoxy Group, 3-pentyloxy group, 2-ethylhexyloxy group, hexyloxy group, octyloxy group, 3,5,5-trimethylhexyloxy group, dodecyloxy group, octadecyloxy group, 2-ethoxyethoxy group, 2-chloro Preferred examples include ethoxy group, 2-phenoxyethoxy group, benzyloxy group, ethoxycarbonylmethoxy group, butoxycarbonylmethoxy group, dibutylaminocarbonylmethoxy group, and diethylaminocarbonylmethoxy group.

The aryloxy group represented by R ⁹ , R ¹⁰ , R ¹¹ and R ¹² may be unsubstituted or may have a substituent. Examples of the substituent that can be introduced into the aryloxy group include a phenyl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, a cyano group, a carboxylic acid group, and a sulfonic acid. Groups and heterocyclic groups are preferred.
Specifically, the aryloxy group represented by R ⁹ , R ¹⁰ , R ¹¹ and R ¹² is preferably an aryloxy group having 6 to 30 carbon atoms in total, such as a phenoxy group, a 4-chlorophenoxy group, 2- Preferable examples include methylphenoxy group, 4-methoxyphenoxy group, 4-cyanophenoxy group, 4-ethoxycarbonylphenoxy group, 4-dibutylaminocarbonylphenoxy group, and 3,5-dichlorophenoxy group.

The alkylthio group represented by R ⁹ , R ¹⁰ , R ¹¹ and R ¹² may be unsubstituted or may have a substituent. Examples of the substituent that can be introduced into the alkylthio group include a phenyl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, a cyano group, a carboxylic acid group, and a sulfonic acid group. And heterocyclic groups are preferred.
Specifically, the alkylthio group represented by R ⁹ , R ¹⁰ , R ¹¹ and R ¹² is preferably an alkylthio group having 1 to 20 carbon atoms in total, for example, methylthio group, ethylthio group, butylthio group, cyclohexylthio group. Preferred examples include a group, an octylthio group, a 2-ethylhexylthio group, a dodecylthio group, a 2-hydroxyethylthio group, and a benzylthio group.
Among these, a C1-C15 alkylthio group is preferable and a methylthio group, an ethylthio group, a butylthio group, and an octylthio group are especially preferable.

The arylthio group represented by R ⁹ , R ¹⁰ , R ¹¹ and R ¹² may be unsubstituted or may have a substituent. Examples of the substituent that can be introduced into the arylthio group include a phenyl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, a cyano group, a carboxylic acid group, and a sulfonic acid group. And heterocyclic groups are preferred.
Specifically, the arylthio group represented by R ³ , R ⁴ , R ⁵ and R ⁶ is preferably an arylthio group having 6 to 20 carbon atoms in total, such as a phenylthio group, a 2-butoxycarbonylphenylthio group, Preferred examples include 2-chlorophenylthio group, 4-chlorophenylthio group, and 4-methylphenylthio group.

The alkylsulfonyl group represented by R ⁹ , R ¹⁰ , R ¹¹ and R ¹² may be unsubstituted or have a substituent. Examples of the substituent that can be introduced into the alkylsulfonyl group include a phenyl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, a cyano group, a carboxylic acid group, and a sulfonic acid. Groups and heterocyclic groups are preferred.
Specifically, the alkylsulfonyl group represented by R ⁹ , R ¹⁰ , R ¹¹ and R ¹² is preferably an alkylsulfonyl group having 1 to 20 carbon atoms in total, for example, a methylsulfonyl group, a butylsulfonyl group, an octyl group. Preferable examples include a sulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, and perfluoroethanesulfonyl group.

The arylsulfonyl group represented by R ⁹ , R ¹⁰ , R ¹¹ and R ¹² may be unsubstituted or may have a substituent. Examples of the substituent that can be introduced into the arylsulfonyl group include a phenyl group, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, a cyano group, a carboxylic acid group, and a sulfonic acid. Groups and heterocyclic groups are preferred.
Specifically, the arylsulfonyl group represented by R ⁹ , R ¹⁰ , R ¹¹ and R ¹² is preferably an arylsulfonyl group having 6 to 30 carbon atoms in total, such as a phenylsulfonyl group, 2-chlorophenylmethylsulfonyl. Preferred examples include a group, 2-chlorophenylsulfonyl group, 4-chlorophenylsulfonyl group, and 4-chlorophenylmethylsulfonyl group.

The diazonio group represented by R ⁹ , R ¹⁰ , R ¹¹ and R ^{12 can} be represented by —N ₂ ⁺ X ⁻ , and X ⁻ represents a counter anion.
X ⁻ represents a counter anion. The counter anion may be either an inorganic anion or an organic anion.
As the inorganic anion, for example, hexafluorophosphate ion, borohydrofluoric acid ion, chloride ion, and sulfuric acid ion are preferable, and among them, hexafluorophosphate ion and borohydrofluoric acid ion are particularly preferable. Further, as the organic anion, for example, polyfluoroalkylcarboxylate ion, polyfluoroalkylsulfonate ion, aromatic carboxylate ion, aromatic sulfonate ion, and ions described in Japanese Patent Application No. 2002-108919 are preferable, Among these, polyfluoroalkylcarboxylate ions, polyfluoroalkylsulfonate ions, and ions described in Japanese Patent Application No. 2002-108919 are particularly preferable.

  Among the diazonium salts represented by the general formula (2), a diazonium salt represented by the following general formula (9) is more preferable, and a diazonium salt represented by the following general formula (10) is more preferable.

In General Formula (9), R ⁷ and R ⁸ each independently represents an alkyl group or an aryl group. R ¹⁹ , R ²⁰ and R ²¹ each independently represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an alkylsulfonyl group or an arylsulfonyl group. X ⁻ represents a counter anion.

In the general formula (9), R ⁷ and R ⁸ has the same meaning as R ⁷ and R ⁸ in the general formula (2), and preferred examples are also the same. R ¹⁹ , R ²⁰ , R ²¹ and X ⁻ are the same as those exemplified for R ⁹ , R ¹⁰ and R ¹² in the general formula (2), and preferred examples are also the same.

In general formula (10), R ⁷ and R ⁸ each independently represents an alkyl group or an aryl group. R ¹⁹ and R ²¹ each independently represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an alkylsulfonyl group or an arylsulfonyl group. R ²² represents an alkyl group or an aryl group. X ⁻ represents a counter anion.

In the general formula (10), R ⁷ and R ⁸ has the same meaning as R ⁷ and R ⁸ in the general formula (2), and preferred examples are also the same. R ¹⁹ , R ²¹ and X ⁻ are the same as those exemplified for R ⁹ and R ¹² in the general formula (2), and preferred examples are also the same.

The alkyl group represented by R ²² may be unsubstituted or substituted. Examples of the substituent that can be introduced into the alkyl group include a phenyl group, a halogen atom, an alkoxy group, and an aryloxy group. An alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, a cyano group, a carboxylic acid group, a sulfonic acid group, and a heterocyclic group are preferred.
Specifically, the alkyl group represented by R ²² is preferably an alkyl group having 1 to 30 carbon atoms in total, such as a methyl group, an ethyl group, a normal propyl group, an isopropyl group, a normal butyl group, an isobutyl group, and a normal pentyl group. Group, isopentyl group, 3-pentyl group, cyclopentyl group, hexyl group, cyclohexyl group, heptyl group, octyl group, 2-ethylhexyl group, 3,5,5-trimethylhexyl group, decyl group, dodecyl group, octadecyl group, 2 -Hydroxyethyl group, 2-benzoyloxyethyl group, 2- (4-butoxyphenoxy) ethyl group, benzyl group, allyl group, methoxyethyl group, ethoxyethyl, dibutylaminocarbonylmethyl, diethylaminocarbonylmethyl group are preferred. .

The aryl group represented by R ²² may be unsubstituted or substituted, and examples of the substituent that can be introduced into the aryl group include a phenyl group, a halogen atom, an alkoxy group, and an aryloxy group. An alkoxycarbonyl group, an acyloxy group, an acylamino group, a carbamoyl group, a cyano group, a carboxylic acid group, a sulfonic acid group, and a heterocyclic group are preferred.
Specifically, the aryl group represented by R ²² is preferably an aryl group having 6 to 30 carbon atoms, and preferably a phenyl group, a 4-chlorophenyl group, a 4-methylphenyl group, and a 4-butoxyphenyl group. Can be mentioned.

  The diazonium salt of the present invention can be produced by a known method. That is, it can be obtained by diazotizing the corresponding aniline using sodium nitrite, nitrosylsulfuric acid, isoamyl nitrite or the like in an acidic solvent.

The method for synthesizing the diazonium salt in the present invention will be described with reference to the compound represented by the general formula (6). The compound represented by the general formula (6) can be synthesized as follows using a compound represented by the following general formula (7) as a raw material.

In the general formula ^{(7), R 13, R} 14, R 15, R 16 and R ¹⁷ are each the same meaning as ^{R 13, R 14, R 15} , R 16 and R ¹⁷ in the general formula described above (6) The preferred embodiment is also the same. R ¹⁸ represents a hydrogen atom or an acyl group. The acyl group is preferably an acyl group having 1 to 30 carbon atoms. For example, formyl group, acetyl group, propionyl group, pivaloyl group, butyroyl group, 4-phenoxybutyroyl group, benzoyl group, (4-ethoxyphenyl) ) Carbonyl group, (2-butoxyphenyl) carbonyl group, (4-chlorophenyl) carbonyl group and the like are preferable, and acetyl group, pivaloyl group, benzoyl group and (4-chlorophenyl) carbonyl group are particularly preferable.

First, the compound represented by the general formula (7) can be synthesized using the compound represented by the general formula (8) as a starting material. R ¹³ in the general formula ^{(8), R 14, R} 15, R 16, R 17 and R ^18, R ¹³ in the general formula ^{(7), R 14, R} 15, R 16, R 17 and R ¹⁸ And preferred specific examples are also the same.

  The following conditions can be applied to the synthesis of the compound represented by the general formula (7). The synthesis reaction here is an oxidation reaction. As the oxidizing agent, chlorine, bromine, iodine, sulfonyl chloride, or sulfuryl chloride is preferable, and bromine is most preferable from the viewpoint of handling and yield. The amount of the oxidizing agent used is preferably 90 to 130%, particularly preferably 100 to 110%, in terms of a molar ratio with respect to the compound represented by the general formula (8). If the amount of the oxidizing agent is small, the raw material remains, and if it is large, the side reaction product may increase.

  The solvent used in the reaction is not particularly limited as long as it does not react with an oxidizing agent, and acetic acid, propionic acid, acetonitrile, chloroform, methylene chloride, ethyl acetate, and chlorobenzene are preferable. In particular, acetic acid, chloroform, and methylene chloride are preferable from the viewpoint of yield. A mixed solvent of these solvents can also be used. The amount of the solvent used may be such that the raw material dissolves. However, if the concentration is high, the viscosity increases and the stirring efficiency decreases, and the volume efficiency decreases at a low concentration. Therefore, the compound represented by the general formula (8) to be used The range of 100-2000% is preferable with respect to the mass of, and more preferably 200-500%. What is necessary is just to select reaction temperature in the range of -10-120 degreeC. In general, the reaction is completed faster as the temperature is higher. However, since the present synthesis method reacts quickly even at room temperature or lower, it is preferably performed in the range of −5 to 35 ° C. in terms of yield. When acetic acid is used as a solvent, it is preferably carried out at 10 ° C. or higher in order to prevent crystallization of acetic acid.

  Synthesis of the compound represented by the general formula (8) is described in “Organic Functional Group Preparations Volume II” (Stanley R. Sandler, Wolf Karo (1971) Academic Press, Inc.), “New Experimental Chemistry Course 14”. Synthesis and Reaction III "((1976) Maruzen Co., Ltd.), J. Chem. Chem. Soc. (C) (1967) p. It can be synthesized by a known method such as 2212-2220.

In synthesizing the diazonium salt in the present invention from the compound represented by the general formula (7), in the case of —NHR ¹⁸ (R ¹⁸ = acyl group), it is converted into —NH ₂ and used. The conversion can be performed under acidic conditions or basic conditions. The acid to be added is hydrochloric acid, sulfuric acid, alkylsulfonic acid, or arylsulfonic acid, and the base to be added is sodium hydroxide, potassium hydroxide, or calcium hydroxide. Is preferred. Compounds that generate an acid upon addition are also preferred, and acetyl chloride and propionyl chloride are preferred. As the reaction solvent, water, methanol, ethanol, propanol, butanol, and acetic acid are preferable, and a mixed solvent thereof is also preferable. The reaction temperature is preferably between room temperature and the boiling point of the solvent, but is preferably performed at a high temperature of 50 ° C. or higher from the viewpoint of reaction rate and solubility.
In the case of —NHR ¹⁸ (R ¹⁸ = hydrogen atom), the compound can be synthesized by diazotization using sodium nitrite, potassium nitrite, nitrosylsulfuric acid, isoamyl nitrite or the like in an acidic solvent.

The diazonium salt in the present invention may be either an oily substance or a crystalline state, but is preferably in a crystalline state in terms of handleability. Moreover, this diazonium salt may be used individually by 1 type, and can also be used together 2 or more types.
In the heat-sensitive recording layer, the content of the diazonium salt in the present invention, preferably in the range of 0.02 to 5 g / m ^2, in the range in particular of 0.1-4 g / m ² in terms of color density Is preferred.

  In addition, the diazonium compound can be stabilized by forming a complex compound using zinc chloride, cadmium tin chloride or the like for stabilizing the diazonium salt.

  Hereinafter, specific examples (Exemplary Compounds A-1 to A-103) of the diazonium salt in the present invention are shown. However, the present invention is not limited to these.

  The heat-sensitive recording material of the present invention has a structure in which the heat-sensitive recording layer according to the present invention is laminated with a heat-sensitive recording layer containing a known diazonium salt and coupler, or an electron-donating colorless dye and an electron-accepting compound as a color forming component. It may be.

Examples of the known diazonium salt include diazonium salts represented by the following general formula (A).
Ar-N ₂ ⁺ X ^1- ... formula (A)
[In General Formula (A), Ar represents a substituted or unsubstituted aryl group, and X ¹⁻ represents an acid anion. ]

  The diazonium salt represented by the general formula (A), like the compound represented by the general formula (1), is a compound that undergoes a coupling reaction with a coupler (described later) by heating to cause color development and decomposes by light. It is. The maximum absorption wavelength of these can be controlled by the position and type of the substituent in the Ar portion.

  Ar in the general formula (A) represents a substituted or unsubstituted aryl group. The aryl group represented by Ar is preferably an aryl group having 6 to 30 carbon atoms, such as a phenyl group, a 2-methylphenyl group, a 2-chlorophenyl group, a 2-methoxyphenyl group, a 2-butoxyphenyl group, 2- (2-ethylhexyloxy) phenyl group, 2-octyloxyphenyl group, 3- (2,4-di-t-pentylphenoxyethoxy) phenyl group, 4-chlorophenyl group, 2,5-dichlorophenyl group, 2, 4,6-trimethylphenyl group, 3-chlorophenyl group, 3-methylphenyl group, 3-methoxyphenyl group, 3-butoxyphenyl group, 3-cyanophenyl group, 3- (2-ethylhexyloxy) phenyl group, 3, 4-dichlorophenyl group, 3,5-dichlorophenyl group, 3,4-dimethoxyphenyl group, 3- (dibutyla Roh carbonyl) phenyl group, 4-cyanophenyl group, 4-methylphenyl group, a 4-methoxyphenyl group,

4-butoxyphenyl group, 4- (2-ethylhexyloxy) phenyl group, 4-benzylphenyl group, 4-aminosulfonylphenyl group, 4-N, N-dibutylaminosulfonylphenyl group, 4-ethoxycarbonylphenyl group, 4 -(2-ethylhexylcarbonyl) phenyl group, 4-fluorophenyl group, 3-acetylphenyl group, 2-acetylaminophenyl group, 4- (4-chlorophenylthio) phenyl group, 4- (4-methylphenyl) thio- 2,5-butoxyphenyl group, 4- (N-benzyl-N-methylamino) -2-dodecyloxycarbonylphenyl group and the like can be mentioned. These groups are alkyl groups, alkoxy groups, alkylthio groups, aryl groups, aryloxy groups, arylthio groups, acyl groups, alkoxycarbonyl groups, carbamoyl groups, carboamido groups, sulfonyl groups, sulfamoyl groups, alkyloxy groups, cyano groups. A group, an amino group, a substituted amino group, a halogen atom, a heterocyclic group, a sulfonamide group, a ureido group, a halogen group, a heterocyclic group, or the like, or may be further substituted.

  Specific examples of diazonium forming the diazonium salt represented by the general formula (A) include 4- (p-tolylthio) -2,5-dibutoxybenzenediazonium, 4- (4-chlorophenylthio) -2, 5-dibutoxybenzenediazonium, 4- (N, N-dimethylamino) benzenediazonium, 4- (N, N-diethylamino) benzenediazonium, 4- (N, N-dipropylamino) benzenediazonium, 4- (N -Methyl-N-benzylamino) benzenediazonium, 4- (N, N-dibenzylamino) benzenediazonium, 4- (N-ethyl-N-hydroxyethylamino) benzenediazonium, 4- (N, N-diethylamino) -3-Methoxybenzenediazonium, 4- (N, N-dimethylamino) -2-methoxy Zendiazonium, 4- (N-benzoylamino) -2,5-diethoxybenzenediazonium, 4-morpholino-2,5-dibutoxybenzenediazonium, 4-anilinobenzenediazonium, 4- [N- (4-methoxy) Benzoyl) amino] -2,5-diethoxybenzenediazonium, 4-pyrrolidino-3-ethylbenzenediazonium, 4- [N- (1-methyl-2- (4-methoxyphenoxy) ethyl) -N-hexylamino]- 2-hexyloxybenzenediazonium, 4- [N- (2- (4-methoxyphenoxy) ethyl) -N-hexylamino] -2-hexyloxybenzenediazonium, 2- (1-ethylpropyloxy) -4- [ Di- (di-n-butylaminocarbonylmethyl) amino] benzenediazoniu , 2-benzylsulfonyl-4-[N-methyl-N-(2-octanoyloxy ethyl)] aminobenzene diazonium, and the like.

X ¹⁻ represents an acid anion, and the acid anion includes a polyfluoroalkylcarboxylic acid having 1 to 9 carbon atoms, a polyfluoroalkylsulfonic acid having 1 to 9 carbon atoms, boron tetrafluoride, tetraphenylboron, hexa Examples thereof include fluorophosphoric acid, aromatic carboxylic acid, and aromatic sulfonic acid. Among these, hexafluorophosphoric acid is preferable in terms of crystallinity.

The maximum absorption wavelength λ _max of the known diazonium salt may be appropriately selected depending on the layer to be used, but is preferably 450 nm or less, more preferably 290 to 440 nm. When the λmax is within the above range, it is possible to prevent raw storability from being lowered, image fixing properties and image storability to be lowered, and hue deterioration in combination with a coupler described later. it can.

  The diazonium salt preferably has a solubility in water of 1% by mass or less and a solubility in ethyl acetate of 5% by mass or more when the number of carbon atoms is 12 or more. In addition, a diazonium salt may be used individually by 1 type, and 2 or more types can also be used together according to the objectives, such as hue adjustment.

-Molten salt-
The heat-sensitive recording layer in the present invention contains a molten salt. In the present invention, the “molten salt” includes structural features of a cation composed of an organic compound containing a hetero atom and an anion formed by dissociation of an inorganic acid, an organic acid or the like.

  In the present invention, any molten salt satisfying the above definition can be used without particular limitation. From the viewpoint of compatibility with an organic compound such as a diazonium salt in the present invention, an imidazolium salt, a pyrazolium salt, a pyridinium salt, It is preferably at least one selected from pyrimidinium salts, pyrazinium salts, thiazolium salts, oxazolium salts, tetraalkylammonium salts, and tetraalkylphosphonium salts, among which imidazolium salts, pyridinium salts, and tetraalkylammonium salts are more preferable. Imidazolium salts are particularly preferred.

  Moreover, the molten salt which can be used suitably for this invention can be represented by following General formula (3) to (5).

〔一般式（３）中、Ｒ²¹およびＲ²²は、それぞれ独立して総炭素数１〜３０のアルキル基、総炭素数７〜４０のアラルキル基を表す。Ｒ²³，Ｒ²⁴およびＲ²⁵は、それぞれ独立して、水素原子、ハロゲン原子、総炭素数１〜１０のアルキル基を表す。Ｒ²¹，Ｒ²²，Ｒ²³，Ｒ²⁴およびＲ²⁵で表されるアルキル基およびアラルキル基は、ハロゲン原子、アルコキシ基、アリールオキシ基、アルコキシカルボニル基、またはアシルオキシ基で置換されていてもよい。Ｙ^-は対アニオンを表す。〕

[In General Formula (3), R ²¹ and R ²² each independently represent an alkyl group having 1 to 30 carbon atoms and an aralkyl group having 7 to 40 carbon atoms. R ²³ , R ²⁴ and R ²⁵ each independently represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 10 carbon atoms. The alkyl group and aralkyl group represented by R ²¹ , R ²² , R ²³ , R ²⁴ and R ²⁵ may be substituted with a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group or an acyloxy group. Y ⁻ represents a counter anion. ]

〔一般式（４）中、Ｒ²⁶は総炭素数１〜３０のアルキル基または総炭素数７〜４０のアラルキル基を表す。Ｒ²⁷，Ｒ²⁸，Ｒ²⁹，Ｒ³⁰およびＲ³¹はそれぞれ独立して、水素原子、ハロゲン原子、総炭素数１〜１０のアルキル基を表す。Ｒ²⁶，Ｒ²⁷，Ｒ²⁸，Ｒ²⁹，Ｒ³⁰およびＲ³¹で表されるアルキル基およびアラルキル基は、ハロゲン原子、アルコキシ基、アリールオキシ基、アルコキシカルボニル基、またはアシルオキシ基で置換されていてもよい。Ｙ^-は対アニオンを表す。〕

[In General Formula (4), R ²⁶ represents an alkyl group having 1 to 30 carbon atoms or an aralkyl group having 7 to 40 carbon atoms in total. R ²⁷ , R ²⁸ , R ²⁹ , R ³⁰ and R ³¹ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms. The alkyl group and aralkyl group represented by R ²⁶ , R ²⁷ , R ²⁸ , R ²⁹ , R ³⁰ and R ³¹ are substituted with a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group or an acyloxy group. Also good. Y ⁻ represents a counter anion. ]

〔一般式（５）中、Ｒ³²，Ｒ³³，Ｒ³⁴およびＲ³⁵は、それぞれ独立して総炭素数１〜３０のアルキル基または総炭素数７〜４０のアラルキル基を表す。Ｒ³²，Ｒ³³，Ｒ³⁴およびＲ³⁵は、ハロゲン原子、アルコキシ基、アリールオキシ基、アルコキシカルボニル基、またはアシルオキシ基で置換されていてもよい。Ｚは、窒素原子またはリン原子を表す。Ｙ^-は対アニオンを表す。〕

[In General Formula (5), R ³² , R ³³ , R ³⁴ and R ³⁵ each independently represents an alkyl group having 1 to 30 carbon atoms or an aralkyl group having 7 to 40 carbon atoms. R ³² , R ³³ , R ³⁴ and R ³⁵ may be substituted with a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group or an acyloxy group. Z represents a nitrogen atom or a phosphorus atom. Y ⁻ represents a counter anion. ]

In General Formula (3), R ²¹ and R ²² each independently represent an alkyl group having 1 to 30 carbon atoms and an aralkyl group having 7 to 40 carbon atoms. From the viewpoint of compatibility with the compound contained in the thermosensitive recording layer. In general formula (3), it is preferable that any one of R ²¹ and R ²² is an alkyl group having 1 to 4 carbon atoms, and it is particularly preferable that either one is a methyl group.
In the general formula (3), the alkyl group having 1 to 30 carbon atoms represented by R ²¹ and R ²² is preferably an alkyl group having 1 to 20 carbon atoms. Examples of the alkyl group include methyl group, ethyl group, isopropyl group, n-butyl group, isopentyl group, 3-pentyl group, t-amyl group, n-hexyl group, cyclohexyl group, n-octyl group, and t-octyl group. , 2-ethylhexyl group, isononyl group, n-dodecyl group, n-tetradecyl group, hexadecyl group, n-octadecyl group and the like, and methyl group, n-octyl group, n-dodecyl group and n-tetradecyl group are preferable. .

The total carbon number 7 to 40 aralkyl group represented by R ²¹ and R ²² in the general formula (3) is preferably an aralkyl group having a total carbon number 7 to 25. Examples of the aralkyl group include a benzyl group, an α-methylbenzyl group, a phenethyl group, a 2-phenylvinyl group, and a (2-pyridinyl) methyl group, and an α-methylbenzyl group is preferable.

In general formula (3), R ²³ , R ²⁴ and R ²⁵ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms.
Examples of the halogen atom represented by R ^{23 to} R ²⁵ in the general formula (3) include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and among them, a fluorine atom and a chlorine atom are preferable.

In the general formula (3), the alkyl group having 1 to 10 carbon atoms represented by R ^{23 to} R ²⁵ is preferably an alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group include methyl group, ethyl group, isopropyl group, n-butyl group, isopentyl group, 3-pentyl group, t-amyl group, n-hexyl group, cyclohexyl group, n-octyl group, and t-octyl group. , 2-ethylhexyl group, isononyl group, n-dodecyl group, hexadecyl group and the like, and methyl group, ethyl group and isopropyl group are preferable.

The alkyl group and aralkyl group represented by R ^{21 to} R ²⁵ may be substituted with a substituent. As the substituent, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, or an acyloxy group is preferable.

The counter anion represented by Y ⁻ in the general formula (3) may be either an inorganic anion or an organic anion.
Preferred examples of the inorganic anion include hexafluorophosphate ion, tetrafluoroborate ion, trifluoromethanesulfonate ion, bis (trifluoromethanesulfone) imide ion, and the like. Hexafluorophosphate ion or bis (trifluoromethanesulfone) ) Imide ions are particularly preferred.
As the organic anion, polyfluoroalkylcarboxylic acid ions, polyfluoroalkylsulfonic acid ions, arylcarboxylic acid ions, arylsulfonic acid ions, or ions described in the specification of Japanese Patent Application No. 2002-108919 are preferable. Fluoroalkylcarboxylate ions, polyfluoroalkylsulfonate ions, or ions described in the specification of Japanese Patent Application No. 2002-108919 are particularly preferred.

In General Formula (4), R ²⁶ represents an alkyl group having 1 to 30 carbon atoms or an aralkyl group having 7 to 40 carbon atoms.
In the general formula (4), the alkyl group having 1 to 30 carbon atoms and the aralkyl group having 7 to 40 carbon atoms represented by R ²⁶ are alkyl groups represented by R ²¹ or R ²² in the general formula (3). And the same meaning as that of the aralkyl group.

In the general formula (4), R ²⁷ , R ²⁸ , R ²⁹ , R ³⁰ and R ³¹ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms.
In the general formula (4), the halogen atom represented by R ^{27 to} R ³¹ and the alkyl group having 1 to 10 carbon atoms are the same as the halogen atom and the alkyl group represented by R ^{23 to} R ²⁵ in the general formula (3). It is synonymous and a preferable aspect is also the same.

The alkyl group and aralkyl group represented by R ^{26 to} R ³¹ may be substituted with a substituent. As the substituent, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, or an acyloxy group is preferable.

The counter anion represented by Y ⁻ in the general formula (4) is synonymous with the counter anion represented by Y ⁻ in the general formula (3), and the preferred embodiment is also the same.

In the general formula (5), R ³² , R ³³ , R ³⁴ and R ³⁵ represent an alkyl group having 1 to 30 carbon atoms or an aralkyl group having 7 to 40 carbon atoms.
The alkyl group having 1 to 30 carbon atoms and the aralkyl group having 7 to 40 carbon atoms represented by R ^{32 to} R ³⁵ in the general formula (5) are represented by R ²¹ or R ²² in the general formula (3). Are the same as the alkyl group and aralkyl group, and the preferred embodiments are also the same.

The alkyl group and aralkyl group represented by R ^{32 to} R ³⁵ may be substituted with a substituent. As the substituent, a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, or an acyloxy group is preferable.

  In General formula (5), Z represents a nitrogen atom or phosphorus, and a nitrogen atom is preferable.

The counter anion represented by Y ⁻ in the general formula (5) is synonymous with the counter anion represented by Y ⁻ in the general formula (3), and the preferred embodiment is also the same.

  Although the specific example (Exemplary compound C-1 to F-10) of the molten salt in this invention is given to the following, this invention is not limited to this.

-Coupler-
The heat-sensitive recording layer according to the present invention contains a coupler (coupling component) that reacts with the diazonium salt described above to develop a color when heated. As the coupler, any compound can be used as long as it can form a dye by coupling with the diazonium salt in a basic atmosphere and / or a neutral atmosphere, and is appropriately selected within a range suitable for the purpose such as hue. can do.

  Examples of the coupler include resorcin, phloroglucin, sodium 2,3-hydroxynaphthalene-6-sulfonate, sodium 2-hydroxy-3-naphthalenesulfonate, 2-hydroxy-3-naphthalenesulfonic acid anilide, 2-hydroxy- 3-naphthalenesulfonic acid morpholinoamide, 2-hydroxy-3-naphthalenesulfonic acid morpholinopropylamide, 2-hydroxy-3-naphthalenesulfonic acid-2-ethylhexyloxypropylamide, 2-hydroxy-3-naphthalenesulfonic acid-2- Ethylhexylamide, sodium 1-hydroxy-8-acetylaminonaphthalene-1,6-disulfonate, 1-hydroxy-8-acetylaminonaphthalene-8,6-disulfonic acid dianilide, 1-hydroxy-2- Fluoroenoic acid morpholinopropylamide, 1,3-dihydroxynaphthalene, 2,2-dihydroxynaphthalene, 2,3-dihydroxy-6-naphthalenesulfonic acid anilide, 2-hydroxy-3-naphthoic acid morpholinopropylamide, 2-hydroxy-3 -Naphthoic acid anilide, 2-hydroxy-3-naphthoic acid-2'-methylanilide, 2-hydroxy-3-naphthoic acid ethanolamide, 2-hydroxy-3-naphthoic acid octylamide, 2-hydroxynaphthoic acid morpholinoethylamide 2-hydroxynaphthoic acid piperidinopropylamide, 2-hydroxynaphthoic acid piperidinoethylamide,

2-hydroxy-3-naphthoic acid-N-dodecyl-oxy-propylamide, 2-hydroxy-3-naphthoic acid tetradecylamide, 6-methoxy-2-hydroxy-3-naphthoic acid anilide, 6-ethoxy-2- Hydroxy-3-naphthoic acid anilide, 6-methoxy-2-hydroxy-3-naphthoic acid morpholinopropylamide, 6-methoxy-2-hydroxy-3-naphthoic acid-2-hydroxyethylamide, acetanilide, acetoacetanilide, 2- Chloro-3- (2,4-di-1-amylphenoxypropylaminocarbonyl) -piparoylacetanilide, benzoylacetanilide, 1-phenyl-3-methyl-5-pyrazolone, 1- (2 ′, 4 ′, 6 ′ -Trichlorophenyl) -3-benzamido-5-pyrazolone, 1- 2 ', 4', 6'-trichlorophenyl) -3-anilino-pyrazolone, mention may be made of 1-phenyl-3-phenylacetamide-5-pyrazolone and the like.

Said coupler may be used individually by 1 type, and may use 2 or more types together.
The content of the coupler in the thermosensitive recording layer is preferably 0.1 to 30 parts by mass with respect to 1 part by mass of the diazonium salt.

-Other ingredients-
In the heat-sensitive recording material of the present invention, as described above, in addition to a combination of a diazonium salt and a coupler (diazo coloring system) as a coloring component, a combination of an electron donating dye precursor and an electron accepting compound (leuco coloring system) ) Can also be used. For example, when the heat-sensitive recording material has a heat-sensitive recording layer composed of a plurality of layers on a support, at least one layer constituting the heat-sensitive recording layer can be formed as a leuco color developing layer.

  Examples of the electron donating dye precursor include triarylmethane compounds, diphenylmethane compounds, thiazine compounds, xanthene compounds, spiropyran compounds, and the like. And xanthene compounds are preferred.

  Specific examples include the following compounds. For example, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (ie crystal violet lactone), 3,3-bis (p-dimethylamino) phthalide, 3- (p-dimethylaminophenyl) -3- (1,3-dimethylindol-3-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (2-methylindol-3-yl) phthalide, 3- (o-methyl-p- Diethylaminophenyl) -3- (2-methylindol-3-yl) phthalide, 4,4′-bis (dimethylamino) benzhydrin benzyl ether, N-halophenylleucooramine, N-2,4,5- Trichlorophenyl leucooramine, rhodamine-B-anilinolactam, rhodamine (p-nitroanilino) lactam, rho Min -B- (p-chloroanilino) lactam, 2-benzylamino-6-diethylaminofluoran, 2-anilino-6-diethylaminofluoran,

2-anilino-3-methyl-6-diethylaminofluorane, 2-anilino-3-methyl-6-cyclohexylmethylaminofluorane, 2-anilino-3-methyl-6-isoamylethylaminofluorane, 2- (o -Chloroanilino) -6-diethylaminofluorane, 2-octylamino-6-diethylaminofluorane, 2-ethoxyethylamino-3-chloro-2-diethylaminofluorane, 2-anilino-3-chloro-6-diethylaminofluorane Benzoyl leucomethylene blue, p-nitrobenzyl leucomethylene blue, 3-methyl-spiro-dinaphthopyran, 3-ethyl-spiro-dinaphthopyran, 3,3′-dichloro-spiro-dinaphthopyran, 3-benzylspirodinaphthopyran, 3-propyl -Spiroge Nzopiran, and the like.

The amount (coating amount) of the electron donating dye precursor in the heat-sensitive recording layer is preferably 0.1 to ² g / m ² in the heat-sensitive recording layer.

  Examples of the electron-accepting compound include phenol derivatives, salicylic acid derivatives, hydroxybenzoic acid esters, etc. Among them, bisphenols and hydroxybenzoic acid esters are particularly preferable.

  Specific examples include the following compounds. For example, 2,2-bis (p-hydroxyphenyl) propane (ie, bisphenol A), 4,4 ′-(p-phenylenediisopropylidene) diphenol (ie, bisphenol P), 2,2-bis (p-hydroxy) Phenyl) pentane, 2,2-bis (p-hydroxyphenyl) ethane, 2,2-bis (p-hydroxyphenyl) butane, 2,2-bis (4′-hydroxy-3 ′, 5′-dichlorophenyl) propane 1,1- (p-hydroxyphenyl) cyclohexane, 1,1- (p-hydroxyphenyl) propane, 1,1- (p-hydroxyphenyl) pentane, 1,1- (p-hydroxyphenyl) -2- Ethyl hexane, 3,5-di (α-methylbenzyl) salicylic acid and polyvalent metal salts thereof, 3,5-di (tert-butyl) E) Salicylic acid and its polyvalent metal salt, 3-α, α-dimethylbenzylsalicylic acid and its polyvalent metal salt, butyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, 2-ethylhexyl p-hydroxybenzoate, p-phenylphenol, p-cumylphenol, and the like.

  The content of the electron-accepting compound in the heat-sensitive recording layer is preferably 0.1 to 30 parts by mass with respect to 1 part by mass of the electron-donating dye precursor.

  An organic base is preferably added to the heat-sensitive recording layer for the purpose of accelerating the coupling reaction between the diazonium salt and the coupler. The organic base is preferably contained in the thermosensitive recording layer together with the diazonium salt and the coupler, and may be used alone or in combination of two or more.

  Examples of the organic base include nitrogen-containing compounds such as tertiary amines, piperidines, piperazines, amidines, formamidines, pyridines, guanidines and morpholines. JP-B-52-46806, JP-A-62-20082, JP-A-57-169745, JP-A-60-94381, JP-A-57-123086, JP-A-58. -1344791, JP-A-60-49991, JP-B-2-24916, JP-B-2-28479, JP-A-60-165288, JP-A-57-185430 Things can also be used.

  Among them, in particular, N, N′-bis (3-phenoxy-2-hydroxypropyl) piperazine, N, N′-bis [3- (p-methylphenoxy) -2-hydroxypropyl] piperazine, N, N′-bis [3- (p-methoxyphenoxy) -2-hydroxypropyl] piperazine, N, N′-bis (3-phenylthio-2-hydroxypropyl) piperazine, N, N′-bis [3- (β-naphthoxy)- 2-hydroxypropyl] piperazine, N-3- (β-naphthoxy) -2-hydroxypropyl-N′-methylpiperazine, 1,4-bis {[3- (N-methylpiperazino) -2-hydroxy] propyloxy} Piperazines such as benzene, N- [3- (β-naphthoxy) -2-hydroxy] propylmorpholine, 1,4-bis (3-morpholino- -Hydroxy-propyloxy) benzene, morpholines such as 1,3-bis (3-morpholino-2-hydroxy-propyloxy) benzene, N- (3-phenoxy-2-hydroxypropyl) piperidine, N-dodecylpiperidine, etc. Of these, pyridines such as piperidine, triphenylguanidine, tricyclohexylguanidine and dicyclohexylphenylguanidine are preferred.

  The organic base content in the heat-sensitive recording layer in the case where an organic base is contained as desired is preferably 0.1 to 30 parts by mass with respect to 1 part by mass of the diazonium salt.

  In addition to the above organic base, a sensitizer can be added to the heat-sensitive recording layer for the purpose of promoting the color development reaction. A sensitizer is a substance that increases the color density during heat recording or lowers the minimum color temperature, and lowers the melting point of couplers, organic bases, diazonium salts, etc., or lowers the softening point of the capsule wall. Thus, a diazonium salt, an organic base, a coupler and the like are easily reacted.

  Specifically, low melting point organic compounds having moderately aromatic groups and polar groups in the molecule are preferable, for example, p-benzyloxybenzoic acid benzyl, α-naphthylbenzyl ether, β-naphthylbenzyl. Ether, β-naphthoic acid phenyl ester, α-hydroxy-β-naphthoic acid phenyl ester, β-naphthol- (p-chlorobenzyl) ether, 1,4-butanediol phenyl ether, 1,4-butanediol-p- Methyl phenyl ether, 1,4-butanediol-p-ethylphenyl ether, 1,4-butanediol-m-methylphenyl ether, 1-phenoxy-2- (p-tolyloxy) ethane, 1-phenoxy-2- ( p-ethylphenoxy) ethane, 1-phenoxy-2- (p-chlorophenoxy) ethane, p- Down Jill biphenyl, and the like.

The heat-sensitive recording layer can contain a binder, and the binder can be appropriately selected from known water-soluble polymer compounds and latexes.
Examples of the water-soluble polymer compound include methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, starch derivatives, casein, gum arabic, gelatin, ethylene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, polyvinyl Alcohol, epichlorohydrin modified polyamide, isobutylene-maleic anhydride salicylic acid copolymer, polyacrylic acid, polyacrylic acid amide and the like, and modified products thereof may be mentioned. Examples of the latexes include styrene-butadiene rubber latex, methyl acrylate- Examples thereof include butadiene rubber latex and vinyl acetate emulsion.

Further, for the purpose of improving fastness to light and heat of a color image or reducing yellowing due to light in an unprinted part (non-image part) after fixing, it contains the following known antioxidants and the like. It is also preferable.
Examples of the antioxidant include, for example, European Patent Publication Nos. EP 223739, 309401, 309402, 309551, 310552, 455416, and German Patent No. 3435443, JP-A-54-48535, JP-A-62-262047, JP-A-63-113536, JP-A-63-163351, JP-A-2-262654, JP-A-2-71262. JP-A-3-121449, JP-A-5-61166, JP-A-5-119449, US Pat. No. 4,814,262, US Pat. No. 4,980,275, and the like.

  In the present invention, the usage form of other components such as couplers, organic bases, and sensitizers is not particularly limited. For example, (1) a method of using a solid dispersion, (2) a method of using an emulsion dispersion (3) A method in which the polymer is dispersed and used, (4) a method in which the latex is dispersed and used, and (5) a method using microencapsulation.

(Method for producing microcapsules)
In the present invention, the diazonium salt in the present invention is preferably encapsulated in a microcapsule in order to improve the raw storage property of the heat-sensitive recording material due to the diazonium salt and also improve the whiteness of the background. The diazonium salt and the molten salt in the present invention are preferably encapsulated in the same microcapsule. The microcapsule is preferably a thermoresponsive microcapsule containing polyurethane and / or polyurea.

  As a method of microencapsulating the diazonium salt in the present invention together with the molten salt in the present invention, a conventionally known method can be used. For example, the oil phase is prepared by simultaneously dissolving or dispersing the diazonium salt represented by the general formula (1) and the molten salt in the present invention in a low-boiling organic solvent that is hardly soluble or insoluble in water. At this time, the molten salt in the present invention is preferably added so as to be 70% by mass or more with respect to the total mass of nonvolatile components (excluding the diazonium salt) contained in the formed microcapsules, and is 75% by mass or more. Is more preferable. The obtained oil phase is mixed in an aqueous phase in which a water-soluble polymer is dissolved, emulsified and dispersed by means such as a homogenizer, and then heated to heat the polymer at the oil droplet interface between the oil phase / aqueous phase. Preferable examples include an interfacial polymerization method that causes a formation reaction to form a microcapsule wall of a polymer substance. This interfacial polymerization method can form capsules with a uniform particle diameter within a short time, and can obtain a recording material excellent in raw storability.

  Here, the term “non-volatile” does not necessarily mean that it does not volatilize at all, but refers to the extent that the abundance cannot be substantially ignored in calculating the mass of components in the capsule after the thermosensitive recording material is completed. Therefore, the “total mass of non-volatile components in the microcapsule excluding the diazonium salt” is a compound that does not dissolve or disperse in water among all the components encapsulated in the microcapsule and has a boiling point of 100 ° C. or higher. It is the total mass of the components, and does not contain volatile components such as a low boiling point solvent (for example, ethyl acetate) that are substantially absent after completion of the thermosensitive recording material. This does not include the capsule wall material component.

  Examples of the low boiling point solvent include acetate ester, methylene chloride, and cyclohexanone. As the non-volatile component, phosphoric acid ester, acrylic acid ester, methacrylic acid ester and other carboxylic acid ester, fatty acid amide, diarylethane, chlorinated paraffin, alcohol solvent, phenol solvent, ether solvent, monoolefin solvent, An epoxy-type solvent etc. are mentioned.

Specific examples of the high boiling point solvent include tricresyl phosphate, trioctyl phosphate, octyl diphenyl phosphate, tricyclohexyl phosphate, dibutyl phthalate, dioctyl phthalate, dilaurate phthalate, dicyclohexyl phthalate, butyl olefinate, diethylene glycol benzoate , Dioctyl sebacate, dibutyl sebacate, dioctyl adipate, trioctyl trimellate, acetyl triethyl citrate, octyl maleate, dibutyl maleate, isoamylbiphenyl, chlorinated paraffin, diisopropylnaphthalene, 1,1′-ditolylethane, 2, 4-ditertiaryamylphenol, N, N-dibutyl-2-butoxy-5-tertioctylaniline, 2-ethylhexyl hydroxybenzoate, poly Examples include ethylene glycol.
Of these, phosphate ester solvents, carboxylic ester solvents, and diarylethane are particularly preferable.

  As the above-mentioned high boiling point solvent, those having unsaturated fatty acids are particularly desirable, and α-methylstyrene dimer and the like can be mentioned. Examples of the α-methylstyrene dimer include “MSD100” manufactured by Mitsui Toatsu Chemical Co., Ltd. . Furthermore, you may add carbonization inhibitors, such as a hindered phenol and a hindered amine, to the said high boiling point solvent.

  Examples of the water-soluble polymer include water-soluble polymers such as polyvinyl alcohol, such as polyvinyl alcohol, silanol-modified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, amino-modified polyvinyl alcohol, itaconic acid-modified polyvinyl alcohol, styrene-anhydrous maleic acid. Acid copolymer, butadiene-maleic anhydride copolymer, ethylene-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer, polyacrylamide, polystyrene sulfonic acid, polyvinyl pyrrolidone, ethylene-acrylic acid copolymer, Examples include gelatin. Of these, carboxy-modified polyvinyl alcohol is preferred.

  The water-soluble polymer may be used in combination with a hydrophobic polymer emulsion or latex. Examples of the emulsion or latex include styrene-butadiene copolymer, carboxy-modified styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, and the like. At this time, a conventionally known surfactant or the like may be added as necessary.

  Examples of the polymer material constituting the microcapsule wall include polyurethane, polyurea, polyamide, polyester, polycarbonate, aminoaldehyde resin, melamine resin, polystyrene, styrene-acrylate copolymer resin, styrene-methacrylate copolymer resin, and gelatin. And polyvinyl alcohol. Among these, polyurethane / polyurea resin is particularly preferable.

  For example, when polyurethane / polyurea is used as a capsule wall material, a microcapsule wall precursor such as polyisocyanate is encapsulated and mixed in an oily medium (oil phase) serving as a core material, and the microcapsule wall precursor is further mixed. After mixing a second substance (for example, polyol, polyamine) that reacts with the aqueous solution into a water-soluble polymer aqueous solution (aqueous phase), the obtained oil phase is emulsified and dispersed in the aqueous phase. By further heating, the polymer formation reaction proceeds at the oil droplet interface, and the microcapsule wall can be formed.

  Specific examples of the polyvalent isocyanate compound are shown below. However, the present invention is not limited to these. For example, m-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-tolylene diisocyanate, 2,4-tolylene diisocyanate, naphthalene-1,4-diisocyanate, diphenylmethane-4,4′-diisocyanate, 3,3′- Diphenylmethane-4,4′-diisocyanate, xylene-1,4-diisocyanate, 4,4′-diphenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, propylene-1,2-diisocyanate, butylene-1,2-diisocyanate, Cyclohexylene-1,2-diisocyanate,

Diisocyanates such as cyclohexylene-1,4-diisocyanate, triisocyanates such as 4,4 ′, 4 ″ -triphenylmethane triisocyanate, toluene-2,4,6-triisocyanate, 4,4′-dimethyl Tetraisocyanates such as phenylmethane-2,2 ′, 5,5′-tetraisocyanate; adducts of hexamethylene diisocyanate and trimethylolpropane; adducts of 2,4-tolylene diisocyanate and trimethylolpropane; Examples thereof include an isocyanate prepolymer such as an adduct of range isocyanate and trimethylolpropane, an adduct of tolylene diisocyanate and hexanetriol, and the like. Moreover, you may use these 2 or more types together as needed. Of these, particularly preferred are those having three or more isocyanate groups in the molecule.

  The above-described method can also be applied to microencapsulation of the known diazonium salt, electron-donating colorless dye, and the like. In the method of microencapsulation, as an organic solvent for dissolving the above-described coupler (and electron accepting compound), organic base, other components such as a sensitizer, and the microcapsule wall precursor and the second substance that reacts therewith The same organic solvent as described above is used.

  As a particle size of a microcapsule, 0.1-2.0 micrometers is preferable and 0.2-1.5 micrometers is more preferable.

(Multicolor thermal recording material)
Hereinafter, a specific configuration aspect of the multicolor heat-sensitive recording material will be described.
The heat-sensitive recording material of the present invention is a monochromatic heat-sensitive recording material having a single heat-sensitive recording layer on a support, and a multi-color heat-sensitive recording material having a heat-sensitive recording layer having a multilayer structure in which a plurality of single-color recording layers are laminated. Either may be sufficient.

  In particular, in the case of a full-color heat-sensitive recording layer composed of three layers of cyan color development, yellow color development, and magenta color development, the three layers on the support are all composed of a diazo color development system or closest to the support. Thermal recording in which the first recording layer is composed of a leuco color developing system combining an electron donating dye and an electron accepting compound, and the second and third recording layers are composed of a diazo coloring system. Material is preferred. Further, it is preferred that the recording layers of each hue are laminated so that cyan, magenta and yellow are developed in order from the support side. In particular, the present invention includes the microcapsules enclosing the diazonium salt in the present invention and the molten salt in the present invention. As such a heat-sensitive recording layer, a layer that develops yellow is optimal.

The heat-sensitive recording material of the present invention can be configured, for example, in the modes shown in the following (a) to (c). That is,
(A) a photofixable recording layer (first recording layer (A layer)) containing a diazonium salt having a maximum absorption wavelength of 365 ± 40 nm and a coupler that reacts with the diazonium salt to cause coloration on the support; And a photofixable recording layer (second recording layer (B layer)) containing a diazonium salt having a maximum absorption wavelength of 420 ± 40 nm and a coupler that reacts with the diazonium salt to develop a color. A recording material having a layer, and a light transmittance adjusting layer and a protective layer provided on the layer as necessary,

  (B) On a support, a recording layer containing an electron donating dye and an electron accepting compound (first recording layer (A layer)), a diazonium salt having a maximum absorption wavelength of 365 ± 40 nm, and the diazonium salt A photo-fixable recording layer (second recording layer (B layer)) containing a coupler that reacts and colors, a diazonium salt having a maximum absorption wavelength of 420 ± 40 nm, and a coupler that reacts with the diazonium salt and colors And a light-fixing type recording layer (third recording layer (C layer)) and a recording layer formed by laminating in this order, and a light transmittance adjusting layer and a protective layer on the layer as necessary Recording material,

  (C) a photofixable recording layer (first recording layer (A layer)) containing a diazonium salt having a maximum absorption wavelength of 350 nm or less on the support and a coupler that causes a color reaction with the diazonium salt; A light-fixing type recording layer (second recording layer (B layer)) containing a diazonium salt having a maximum absorption wavelength of 365 ± 40 nm and a coupler that reacts with the diazonium salt to develop a color; and a maximum absorption wavelength of 420 ± 40 nm. A photofixable recording layer (third recording layer (C layer)) containing a certain diazonium salt and a coupler that reacts with the diazonium salt to develop a color, and has a recording layer formed by laminating in this order, A recording material provided with a light transmittance adjusting layer and a protective layer as required on the layer.

The method for multicolor recording will be described below with respect to (b) or (c).
First, the third recording layer (C layer) is heated to cause the diazonium salt and coupler contained in the layer to develop color. Next, after irradiation with light having an emission center wavelength of 430 ± 30 nm to decompose and photofix the unreacted diazonium salt contained in the C layer, the second recording layer (B layer) is sufficiently colored. Heat is applied to color the diazonium salt and coupler contained in the layer. At this time, the C layer is also strongly heated at the same time, but the diazonium salt has already been decomposed (photofixed), and the color development ability is lost, so no color is developed. Furthermore, after irradiating light with an emission center wavelength of 360 ± 20 nm, the diazonium salt contained in the B layer was decomposed and photofixed, and finally, sufficient heat was applied to develop the first recording layer (A layer). To develop color. At this time, the recording layers of the C layer and the B layer are also strongly heated at the same time. However, since the diazonium salt has already been decomposed and the coloring ability is lost, no color is developed.

  Further, when all the recording layers (A layer, B layer, and C layer) are diazo type recording layers, the B layer and the C layer need to be subjected to photofixing after color development. For the A layer on which image recording is performed, it is not always necessary to perform optical fixing.

  The light source for fixing used for light fixing can be appropriately selected from known light sources such as various fluorescent lamps, xenon lamps, mercury lamps and the like. It is preferable to use a light source whose spectrum substantially matches the absorption spectrum of the diazonium chloride used for the recording material.

(Other layers)
The heat-sensitive recording material of the present invention preferably has a heat-sensitive recording layer comprising a single layer or a plurality of layers on the support, and further comprises other layers such as a light transmittance adjusting layer and a protective layer. Can do.

-Light transmittance adjustment layer-
The light transmittance adjusting layer contains an ultraviolet absorber precursor and does not function as an ultraviolet absorber before irradiation with light having a wavelength in a region necessary for fixing, so that the light transmittance is high, and the light fixing type thermosensitive recording layer is formed. When fixing, the wavelength of the region necessary for fixing is sufficiently transmitted, and the visible light transmittance is high, so that the fixing of the heat-sensitive recording layer is not hindered. This ultraviolet absorbent precursor is preferably contained in the microcapsule.
Examples of the compound contained in the light transmittance adjusting layer include compounds described in JP-A-9-1928.

The ultraviolet absorber precursor functions as an ultraviolet absorber by reacting with light or heat after the light irradiation of the wavelength of the region necessary for fixing by light irradiation of the thermosensitive recording layer is completed. Most of the light having the wavelength in the region necessary for fixing the region is absorbed by the ultraviolet absorber, the transmittance is lowered, and the light resistance of the heat-sensitive recording material is improved, but there is no visible light absorption effect. The light transmittance is substantially unchanged.
At least one light transmittance adjusting layer can be provided in the heat sensitive recording material, and most preferably, it is formed between the heat sensitive recording layer and the outermost protective layer. You may make it also use. The characteristics of the light transmittance adjusting layer can be arbitrarily selected according to the characteristics of the thermosensitive recording layer.

A coating liquid for forming a light transmittance adjusting layer (light transmittance adjusting layer coating liquid) is obtained by mixing the above-described components. The light transmittance adjusting layer coating solution can be formed by coating by a known coating method such as a bar coater, an air knife coater, a blade coater, or a curtain coater. The light transmittance adjusting layer may be applied simultaneously with the heat-sensitive recording layer or the like. For example, the heat-sensitive recording layer may be applied, and after the heat-sensitive recording layer is dried, the heat-sensitive recording layer may be applied on the layer. Good.
The dry coating amount of the light transmittance adjusting layer, 0.8~4.0g / m ² is preferred.

-Protective layer-
The protective layer contains a pigment, a lubricant, a surfactant, a dispersant, a fluorescent brightener, a metal soap, a hardener, an ultraviolet absorber, a crosslinking agent and the like together with a binder.
The binder is within the range not impairing barrier properties and workability, for example, polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, starches, gelatin, gum arabic, casein, styrene-maleic anhydride copolymer hydrolyzate, An ethylene-maleic anhydride copolymer hydrolyzate, isobutylene-maleic anhydride copolymer hydrolyzate, polyvinyl alcohol, modified polyvinyl alcohol, polyacrylamide, and the like can be appropriately selected for use.

In addition to the above, other binders include synthetic rubber latex, synthetic resin emulsion, and the like, for example, styrene-butadiene rubber latex, acrylonitrile-butadiene rubber latex, methyl acrylate-butadiene rubber latex, vinyl acetate emulsion, and the like. .
As content of the said binder, 10-500 mass% is preferable with respect to the pigment in a protective layer, and 50-400 mass% is more preferable.

  For the purpose of further improving the water resistance, it is effective to use a crosslinking agent and a catalyst for promoting the reaction in combination. Examples of the crosslinking agent include epoxy compounds, blocked isocyanates, vinyl sulfone compounds, aldehyde compounds. , Methylol compounds, boric acid, carboxylic acid anhydrides, silane compounds, chelate compounds, halides, and the like, and those capable of adjusting the pH of the coating solution for forming the protective layer to 6.0 to 7.5 are preferable. Examples of the catalyst include known acids and metal salts, and those that can adjust the pH of the coating solution to 6.0 to 7.5 as described above are preferable.

  As the pigment in the protective layer, all known organic or inorganic pigments can be used. Specifically, calcium carbonate, aluminum hydroxide, barium sulfate, titanium oxide, talc, wax, kaolin, calcined kaolin, amorphous Silica, colloidal silica, urea formalin resin powder, polyethylene resin powder, benzoguanamine resin powder and the like. These can be used alone or in admixture of two or more.

Examples of the lubricant preferably include zinc stearate, calcium stearate, paraffin wax, and polyethylene wax.
The surfactant is used to form a uniform protective layer on the thermosensitive recording layer. Preferred examples of such surfactants include sulfosuccinic acid-based alkali metal salts and fluorine-containing surfactants. Specific examples include di- (2-ethylhexyl) sulfosuccinic acid and di- (n-hexyl). ) Sodium salts such as sulfosuccinic acid and ammonium salts.

The coating solution for forming the protective layer (protective layer coating solution) is obtained by mixing the above-described components. Furthermore, you may add a mold release agent, a wax, a water repellent, etc. as needed.
The heat-sensitive recording material of the present invention can be formed by applying a protective layer coating solution on a heat-sensitive recording layer formed on a support by a known coating method. Examples of the known coating method include a method using a bar coater, an air knife coater, a blade coater, a curtain coater and the like. However, the protective layer may be applied simultaneously with the heat-sensitive recording layer and the light transmittance adjusting layer.For example, after applying the coating liquid for forming the heat-sensitive recording layer and once drying the heat-sensitive recording layer, the protective layer is formed on the layer. It may be formed by coating.

The dry coating amount of the protective layer is preferably ^{0.2~7g / m 2, 1~4g / m} 2 is more preferable. When the dry coating amount is 0.2 to 7 g / m ² , the water resistance and heat sensitivity are excellent. You may perform a calendar process after application | coating formation of a protective layer as needed.

-Intermediate layer-
When the thermosensitive recording layer is composed of a plurality of layers, it is preferable to provide an intermediate layer between the recording layers. The intermediate layer may further contain pigments, lubricants, surfactants, dispersants, fluorescent brighteners, metal soaps, ultraviolet absorbers and the like in various binders as in the protective layer. As the binder, the same binder as the protective layer can be used.

(Support)
Examples of the support constituting the heat-sensitive recording material of the present invention include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), triacetyl cellulose (TAC), paper, plastic resin laminated paper, and synthetic paper. In order to obtain a transparent thermosensitive recording material, it is necessary to use a transparent support. Examples of the transparent support include polyester films such as polyethylene terephthalate and polybutylene terephthalate, cellulose triacetate films, polypropylene, and the like. Examples thereof include synthetic polymer films such as polyolefin films such as polyethylene.

  The support can be used alone or in combination. As thickness of the said synthetic polymer film, 25-300 micrometers is preferable and 100-250 micrometers is more preferable.

  The synthetic polymer film may be colored in an arbitrary hue. As a method of coloring the polymer film, a method of kneading a dye in advance with a resin before forming the film and forming it into a film, a dye having an appropriate solvent Examples thereof include a method of preparing a coating solution dissolved in 1 and applying and drying the same on a transparent and colorless resin film by a known coating method, for example, a gravure coating method, a roller coating method, a wire coating method, or the like. Among them, a polyester resin such as polyethylene terephthalate or polyethylene naphthalate kneaded with a blue dye is preferably formed into a film and subjected to heat treatment, stretching treatment and antistatic treatment.

  The above heat-sensitive recording layer (recording layer), protective layer, light transmittance adjusting layer, intermediate layer, etc. are formed on the support by blade coating, air knife coating, gravure coating, roll coating coating, spray coating, It can be formed by applying a coating solution for forming each layer by a known coating method such as a dip coating method or a bar coating method and then drying it.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the following description, “part” means “part by mass” unless otherwise specified.

[Example 1]
<< Synthesis of Exemplary Compound A-3 >>
23.7 g of the following compound A-3- (a) was dissolved in 100 ml of methanol, 21 ml of concentrated hydrochloric acid was added and refluxed for 3 hours, and then cooled to 0 ° C. A solution consisting of 4.1 g of sodium nitrite and 10 ml of water was added dropwise to the resulting solution, and the mixture was stirred at 10 ° C. for 0.5 hour. Then, 12.9 g of potassium hexafluorophosphate was added to the reaction mixture, and the mixture was stirred at room temperature for 1 hour. Stir for hours. Further, 200 ml of water was added for crystallization. The precipitated crystals were collected by filtration, washed with water, and then recrystallized from a mixed solvent of ethyl acetate and isopropanol. The obtained crystal was dried to obtain 27.5 g of exemplary compound A-3.

The obtained exemplary compound A-3 was identified by ¹ H-NMR. The data is shown below.
1H-NMR (CDCl ₃ ) δ; 8.01 (s, 1H), 7.24-7.40 (m, 5H), 6.32 (s, 1H), 5.34 (s, 2H), 4 .37 (m, 1H), 3.32 (t, 2H), 1.55-1.74 (m, 6H), 1.43 (m, 2H), 0.96 (t, 3H),. 89 (t, 6H)
Further, the maximum absorption wavelength λmax in the ultraviolet-visible absorption spectrum in methanol was 412 nm, and the extinction coefficient ε was 1.5 × 10 ⁴ .

<Production of thermal recording material>
(1) Preparation of gelatin solution for preparing coating solution <Preparation of phthalated gelatin aqueous solution>
Phthalated gelatin (trade name: MGP gelatin, manufactured by Nippi Collagen Co., Ltd.) 32 parts, 1,2-benzothiazolin-3-one (3.5% methanol solution, manufactured by Daitokemix Co., Ltd.) 0.914 parts, ion 367.1 parts of exchange water was mixed and dissolved at 40 ° C. to obtain a phthalated gelatin aqueous solution.

<Preparation of alkali-treated gelatin aqueous solution>
25.5 parts of alkali-treated low ion gelatin (trade name: # 750 gelatin, manufactured by Nitta Gelatin Co., Ltd.), 1,2-benzothiazolin-3-one (3.5% methanol solution, manufactured by Taito Chemix Co., Ltd.) ) 0.729 parts, calcium hydroxide 0.153 parts, and ion-exchanged water 143.6 parts were mixed and dissolved to obtain an alkali-treated gelatin aqueous solution.

(2) Preparation of yellow thermosensitive recording layer solution <Preparation of diazonium salt compound-encapsulated microcapsule solution (a)>
To 18.1 parts of ethyl acetate, 4.7 parts of the following diazonium compound (A-3), 2.56 parts of monoisopropylbiphenyl, 5.1 parts of diphenyl phthalate and 1.92 parts of the above exemplified compound C-6 and diphenyl 0.6 parts of (2,4,6-trimethylbenzoyl) phosphine oxide (trade name: Lucillin TPO, manufactured by BASF Japan Ltd.) was added and dissolved uniformly. A mixture of xylylene diisocyanate / trimethylolpropane adduct and xylylene diisocyanate / bisphenol A adduct (trade name: Takenate D119N (50 mass% ethyl acetate solution), Mitsui Takeda Chemical ( 8.6 parts) was added to obtain a mixed solution (I).
Separately, 16.3 parts of ion-exchanged water and 0.41 part of Scraph AG-8 (50% by mass, manufactured by Nippon Seika Co., Ltd.) are added to 58.6 parts of the above phthalated gelatin aqueous solution, and the mixed liquid (II) is added. Obtained.

  The mixed solution (I) was added to the mixed solution (II), and the mixture was emulsified and dispersed using a homogenizer (manufactured by Nippon Seiki Seisakusho). 20 parts of water was added to the obtained emulsion to make it uniform, and then ethyl acetate was removed. Thereafter, 4.1 parts of ion exchange resin Amberlite IRA68 (manufactured by Organo Corporation) and 8.2 parts of Amberlite IRC50 (manufactured by Organo Corporation) were added to the emulsion and further stirred. Thereafter, the ion exchange resin was removed, and the concentration was adjusted so that the solid content of the capsule solution was 20%, whereby a diazonium salt compound-encapsulating microcapsule solution (a) was obtained.

<Preparation of coupler compound emulsion (a)>
33.0 parts of ethyl acetate, 9.9 parts of the following coupler compound, 9.9 parts of triphenylguanidine (manufactured by Hodogaya Chemical Co., Ltd.), 4,4 ′-(m-phenylenediisopropylidene) diphenol (trade name: 20.8 parts of bisphenol M (manufactured by Mitsui Petrochemical Co., Ltd.), 3,3,3 ′, 3′-tetramethyl-5,5 ′, 6,6′-tetra (1-propyloxy) -1,1 '-Spirobisindane 3.3 parts (manufactured by Sankyo Chemical Co., Ltd.), 4- (2-ethylhexyloxy) benzenesulfonic acid amide (manac Co., Ltd.) 13.6 parts, 4-n-pentyloxybenzene Dissolve 6.8 parts of sulfonic acid amide (Manac Co., Ltd.) and 4.2 parts of calcium dodecylbenzenesulfonate (trade name: Pionein A-41-C, 70% methanol solution, Takemoto Yushi Co., Ltd.). The mixed liquid (III) It was.
Separately, 107.3 parts of ion-exchanged water was mixed with 206.3 parts of the above alkali-treated gelatin aqueous solution to obtain a mixed liquid (IV).

The mixed solution (III) was added to the mixed solution (IV), and the mixture was emulsified and dispersed using a homogenizer (manufactured by Nippon Seiki Seisakusho Co., Ltd.). After stirring the obtained coupler compound emulsion, the concentration was adjusted so that the solid content concentration was 26.5% by mass.
Furthermore, 9 parts of SBR latex (trade name: SN-307, 48% solution, manufactured by Sumika Aves Latex Co., Ltd.) with a concentration adjusted to 26.5% are added to 100 parts of the coupler compound emulsion. Then, the mixture was uniformly stirred to obtain a coupler compound emulsion (a).

<Preparation of coating liquid (a)>
The diazonium salt compound-encapsulated microcapsule liquid (a) and the coupler compound-emulsified liquid (a) are mixed so that the mass ratio of the encapsulated coupler compound / diazo compound is 2.2 / 1, and thermal recording is performed. A layer coating solution (a) was obtained.

(3) Preparation of coating solution for each layer other than heat-sensitive recording layer <Preparation of coating solution for intermediate layer>
Alkali-treated low ion gelatin (trade name: # 750 gelatin, Nitta Gelatin Co., Ltd.) 100.0 parts, 1,2-benzothiazolin-3-one (3.5% methanol solution, Daitokemix Co., Ltd.) 2.86 parts, 0.5 parts of calcium hydroxide, and 521.643 parts of ion-exchanged water were dissolved to obtain a gelatin aqueous solution for preparing an intermediate layer.
10.0 parts gelatin aqueous solution for preparing the intermediate layer, 0.05 parts sodium 4-[(4-nonylphenoxy) trioxyethylene] butylsulfonate (2.0% by mass aqueous solution, Sankyo Chemical Co., Ltd.) , 1.5 parts of boric acid (4.0% by mass aqueous solution), 0.19 part of polystyrenesulfonic acid (partially potassium hydroxide neutralized) aqueous solution (5% by mass), 4% by mass aqueous solution of the following compound (J) 3 .42 parts, 1.13 parts of a 4% by weight aqueous solution of the following compound (J ′) and 0.67 parts of ion-exchanged water were mixed to obtain a coating solution for an intermediate layer.

<Preparation of coating solution for light transmittance adjusting layer>
-Preparation of UV absorber precursor microcapsule solution-
14.5 parts of [2-allyl-6- (2H-benzotriazol-2-yl) -4-t-octylphenyl] benzenesulfonate as an ultraviolet absorber precursor in 71 parts of ethyl acetate, 2,5-di ( t-octyl) hydroquinone 5.0 parts, tricresyl phosphate 1.9 parts, α-methylstyrene dimer (trade name: MSD-100, manufactured by Mitsui Chemicals, Inc.) 5.7 parts, calcium dodecylbenzenesulfonate (trade name) 0.45 part of Pionein A-41-C (70% methanol solution), Takemoto Yushi Co., Ltd.) was dissolved and dissolved uniformly. Add 54.7 parts of xylylene diisocyanate / trimethylolpropane adduct (trade name: Takenate D110N (75% by mass ethyl acetate solution), manufactured by Mitsui Takeda Chemical Co., Ltd.) as capsule wall material to the above mixture, and uniformly The mixture was stirred to obtain an ultraviolet absorber precursor mixed solution (VII).
Separately, 52 parts of itaconic acid-modified polyvinyl alcohol (trade name: KL-318, manufactured by Kuraray Co., Ltd.) is mixed with 8.9 parts of a 30% by mass phosphoric acid aqueous solution and 532.6 parts of ion-exchanged water, and an ultraviolet absorber precursor. A PVA aqueous solution for a microcapsule solution was prepared.

  The ultraviolet absorbent precursor mixture liquid (VII) was added to 518 parts of the PVA aqueous solution for the ultraviolet absorbent precursor microcapsule liquid, and the mixture was emulsified and dispersed using a homogenizer (manufactured by Nippon Seiki Seisakusho Co., Ltd.). 254.1 parts of ion exchange water was added to the obtained emulsion and stirred. Thereafter, 94.3 parts of ion exchange resin Amberlite MB-3 (manufactured by Organo Corp.) was added and further stirred. Thereafter, the ion exchange resin was removed, and the concentration was adjusted so that the solid concentration of the capsule liquid was 13.5%. To this capsule solution 859.1 parts, carboxy-modified styrene butadiene latex (trade name: SN-307, (48% by mass aqueous solution), manufactured by Sumitomo Nougatac Co., Ltd.) 2.416 parts, and ion-exchanged water 39.5 parts were mixed. Thus, an ultraviolet absorber precursor microcapsule solution was obtained.

-Preparation of coating solution for light transmittance adjusting layer-
1000 parts of the above-mentioned ultraviolet absorber precursor microcapsule liquid, fluorine-based surfactant (trade name: Megafac F-120, 5 mass% aqueous solution, Dainippon Ink and Chemicals, Inc.) 5.2 parts, 4 mass% water 7.75 parts of sodium oxide aqueous solution and 73.39 parts of sodium (4-nonylphenoxytrioxyethylene) butyl sulfonate (manufactured by Sankyo Chemical Co., Ltd., 2.0 mass% aqueous solution) are mixed, and the light transmittance adjusting layer A coating solution was obtained.

<Preparation of coating solution for protective layer>
-Preparation of polyvinyl alcohol solution for protective layer-
160 parts of vinyl alcohol-alkyl vinyl ether copolymer (trade name: EP-130, manufactured by Denki Kagaku Kogyo Co., Ltd.), mixed liquid of sodium alkyl sulfonate and polyoxyethylene alkyl ether phosphate ester (trade name: Neoscore CM-57 , (54 mass% aqueous solution), manufactured by Toho Chemical Co., Ltd.) 8.74 parts and 3832 parts of ion-exchanged water were mixed and dissolved to obtain a uniform polyvinyl alcohol solution for a protective layer.

-Preparation of pigment dispersion for protective layer-
Barium sulfate (trade name: BF-21F, barium sulfate content 93% or more, manufactured by Sakai Chemical Industry Co., Ltd.) 8 parts anionic special polycarboxylic acid type polymer activator (trade name: Poise 532A (40 mass) % Aqueous solution), manufactured by Kao Co., Ltd.) 0.2 parts and ion-exchanged water 11.8 parts were mixed and dispersed in a dynomill to prepare a pigment dispersion for protective layer. To 45.6 parts of the barium sulfate dispersion, 8.1 parts of colloidal silica (trade name: Snowtex O (20 mass% aqueous dispersion), manufactured by Nissan Chemical Co., Ltd.) was added to obtain a dispersion. .

-Preparation of matting agent dispersion for protective layer-
1,2-benzisothiazolin-3 (2H) -one aqueous dispersion (trade name: PROXEL BD, IC) was added to 220 parts of wheat starch (trade name: wheat starch S, manufactured by Shinshin Food Industry Co., Ltd.). I) (trade name) 3.81 parts and ion-exchanged water 1976.19 parts were mixed and dispersed uniformly to obtain a protective layer matting agent dispersion.

-Preparation of coating blend liquid for protective layer-
Fluorosurfactant (trade name: Megafac F-120, 5% by weight aqueous solution, Dainippon Ink & Chemicals, Inc.) 40 parts, (4-nonylphenoxytrioxyethylene) 1000 parts of the above-mentioned polyvinyl alcohol solution for protective layer ) 50 parts of sodium butyl sulfonate (manufactured by Sankyo Chemical Co., Ltd., 2.0% by weight aqueous solution), 49.87 parts of the pigment dispersion for the protective layer, 16.65 parts of the matting agent dispersion for the protective layer, stearin 48.7 parts of zinc acid dispersion (trade name: Hydrin F115, 20.5 mass% aqueous solution, manufactured by Chukyo Yushi Co., Ltd.) was uniformly mixed to obtain a coating blend liquid for protective layer.

(4) Production of support with undercoat layer <Preparation of undercoat layer solution>
Enzymatically decomposed gelatin (average molecular weight: 10,000, PAGI viscosity: 15 mP, PAGI jelly strength: 20 g) 40 parts of ion-exchanged water and stirred and dissolved at 40 ° C. to prepare a gelatin aqueous solution for an undercoat layer.
Separately, 8 parts of water-swelling synthetic mica (aspect ratio: 1000, trade name: Somasif ME100, manufactured by Coop Chemical Co., Ltd.) and 92 parts of water were mixed and then wet-dispersed with Viscomill, and the average particle size was 2.0 μm. A mica dispersion was obtained. Water was added to the mica dispersion so that the mica concentration was 5% by mass and mixed uniformly to prepare a desired mica dispersion.
Next, 120 parts of water and 556 parts of methanol were added to 100 parts of the 40% by weight gelatin aqueous solution at 40 ° C. and stirred sufficiently, and then 5 parts by weight of the mica dispersion 208 parts were added and stirred sufficiently. 9.8 parts of 66 mass% polyethylene oxide type surfactant were added. Then, the liquid temperature was kept at 35 to 40 ° C., and 7.3 parts of an epoxy compound gelatin hardener (trade name: Denacol EX80, manufactured by Nagase Kasei Kogyo Co., Ltd.) was added, and an undercoat layer coating solution (5.7 % By weight) was prepared.

<Preparation of support with undercoat layer>
LBPS 50 parts LBPK 50 parts wood pulp is beaten to 300 cc (300 cm ³ ) Canadian freeness with a disk refiner, epoxidized behenamide 0.5 parts, anionic polyacrylamide 1.0 parts, aluminum sulfate 1.0 parts In addition, 0.1 part of polyamide polyamine epichlorohydrin and 0.5 part of cationic polyacrylamide were added at an absolute dry weight ratio to the pulp, and a base paper having a basis weight of 114 g / m ² was made with a long net paper machine, and the thickness was 100 μm by calendering. Adjusted.
Next, after corona discharge treatment was performed on both sides of the base paper, polyethylene was coated to a resin thickness of 36 μm using a melt extruder to form a resin layer consisting of a mat surface (this surface is called the back surface). Next, using a melt extruder on the side opposite to the surface on which the resin layer is formed, a 10% by mass of anatase-type titanium dioxide and a polyethylene containing a trace amount of ultramarine are coated so that the resin thickness is 50 μm and the glossy surface is formed. A resin layer was formed (this surface is called a front surface). After the corona discharge treatment of the polyethylene resin-coated surface of the back surface, aluminum oxide (trade name: Alumina Sol 100, manufactured by Nissan Chemical Industries, Ltd.) / Silicon dioxide (trade name: Snowtex O, Nissan Chemical Industries ( Co., Ltd.) = 1/2 (mass ratio) was dispersed in water, and 0.2 g / m ^{2 was} applied by weight after drying. Next, the front surface of the polyethylene resin-coated surface was subjected to corona discharge treatment, and then the undercoat liquid was applied to obtain a support with an undercoat layer.

(5) Production of thermosensitive recording material <Coating of coating solution for each thermosensitive recording layer>
From the bottom on the support with the undercoat layer, the intermediate layer coating solution, the thermosensitive recording layer coating solution (a), the light transmittance adjusting layer coating solution, and the protective layer coating solution 4 in this order. The layers were applied simultaneously and dried to obtain a thermosensitive recording material (T-1).

[Example 2]
A thermosensitive recording material (T-2) was prepared in the same manner as in Example 1 except that the following diazonium salt compound (A-4) was used instead of the diazonium salt compound (A-3) used in Example 1. Obtained.

[Example 3]
In Example 1, the following diazonium salt compound (A-31) was used in place of the diazonium salt compound (A-3), and the above exemplified compound C-17 was used in place of the exemplified compound C-6. In the same manner as in Example 1, a thermosensitive recording material (T-3) was obtained.

[Example 4]
In Example 1, a thermosensitive recording material (T-4) was obtained in the same manner as in Example 1 except that the exemplified compound D-15 was used instead of the exemplified compound C-6.

[Example 5]
A heat-sensitive recording material (T-5) was obtained in the same manner as in Example 1 except that Example Compound E-7 was used instead of Example Compound C-6 in Example 1.

[Comparative Example 1]
A thermosensitive recording material (H-1) was obtained in the same manner as in Example 1 except that “diphenyl phthalate” was used in place of Exemplified Compound C-6 in Example 1.

[Comparative Example 2]
A heat-sensitive recording material (H-3) was obtained in the same manner as in Example 1 except that the following diazonium salt compound (B) was used instead of the diazonium salt compound (A-3) in Example 4.

[Evaluation]
The following evaluation was performed for each heat-sensitive recording material obtained from the above. The results are shown in Table 1.

(1) Raw storage (thermal stability)
Each heat-sensitive recording material before recording was forcibly stored (forced test) for 72 hours under an environmental condition of 60 ° C./30% relative humidity. Thereafter, the thermal recording material forcibly stored and the thermal recording material not forcibly stored are applied to the thermal head using a thermal head (KST type) manufactured by Kyocera Corporation so that the recording energy is 23 mJ / mm ^2. The voltage and pulse width were determined, and each thermal recording material was thermally printed to form a yellow image. After image formation, each heat-sensitive recording material after printing was irradiated for 25 seconds under an ultraviolet lamp having an emission center wavelength of 365 nm and an output of 40 W.
Next, the maximum density of the image portion colored yellow was measured using X-rite 310TR (manufactured by Nippon Flat Equipment Co., Ltd.), and a non-forced thermal recording material (D ¹ ) and a forced storage thermal recording material ( D ²⁾ the maximum concentration concentration ratio of the ^{(D 2 / D 1 × 100} (%)) was determined.

(2) Dark storage stability The heat-sensitive recording material was thermally recorded by the same method as in (1) above and stored for 72 hours at 23 ° C./52% relative humidity, and at 35 ° C./80% relative humidity. The color density of the yellow image with the compulsory storage (forced dark storage) for 72 hours was measured using an X-rite 310TR (manufactured by Nippon Flat Equipment Co., Ltd.), and a non-forced dark storage thermal recording material (D ³ ) And the thermosensitive recording material (D ⁴ ) having been subjected to forced dark storage, the maximum density ratio (D ⁴ / D ³ × 100 (%)) was determined.

As can be seen from the results of Table 1 above, it can be seen that the heat-sensitive recording materials of the examples in which the diazonium salt compound of the present invention and the molten salt of the present invention are used are excellent in both raw and dark storability. .
On the other hand, the heat-sensitive recording material of Comparative Example 1 that did not use the molten salt in the present invention has particularly low dark storage stability. Further, Comparative Example 2 that did not use the diazonium salt in the present invention has raw storage stability. It was very low.

Claims (5)

A thermosensitive recording material having a thermosensitive recording layer containing a diazonium salt and a coupler that develops color by reacting with the diazonium salt on a support, wherein the diazonium salt is a compound represented by the following general formula (1) And at least one selected from the compounds represented by formula (2), and the heat-sensitive recording layer further contains a molten salt.

[In General Formula (1), R ¹ and R ² each independently represents an alkyl group, an aryl group, or an aralkyl group. R ³ , R ⁴ , R ⁵ and R ⁶ each independently represents a hydrogen atom or a monovalent substituent. However, at least one of R ³ , R ⁴ , R ⁵ and R ⁶ represents —N ₂ ⁺ X ⁻ . X ⁻ represents a counter anion. ]

[In General Formula (2), R ⁷ and R ⁸ each independently represents an alkyl group or an aryl group. R ⁹ , R ¹⁰ , R ¹¹ and R ¹² each independently represents a hydrogen atom or a monovalent substituent. However, at least one of R ⁹ , R ¹⁰ , R ¹¹ and R ¹² represents —N ₂ ⁺ X ⁻ . X ⁻ represents a counter anion. ]   The molten salt is at least one selected from imidazolium salts, pyrazolium salts, pyridinium salts, pyrimidinium salts, pyrazinium salts, thiazolium salts, oxazolium salts, tetraalkylammonium salts, and tetraalkylphosphonium salts. The heat-sensitive recording material according to claim 1. The heat-sensitive recording material according to claim 1, wherein the molten salt is at least one selected from compounds represented by the following general formulas (3) to (5).

[In General Formula (3), R ²¹ and R ²² each independently represent an alkyl group having 1 to 30 carbon atoms and an aralkyl group having 7 to 40 carbon atoms. R ²³ , R ²⁴ and R ²⁵ each independently represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 10 carbon atoms. The alkyl group and aralkyl group represented by R ²¹ , R ²² , R ²³ , R ²⁴ and R ²⁵ may be substituted with a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group or an acyloxy group. Y ⁻ represents a counter anion. ]

[In General Formula (4), R ²⁶ represents an alkyl group having 1 to 30 carbon atoms or an aralkyl group having 7 to 40 carbon atoms in total. R ²⁷ , R ²⁸ , R ²⁹ , R ³⁰ and R ³¹ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms. The alkyl group and aralkyl group represented by R ²⁶ , R ²⁷ , R ²⁸ , R ²⁹ , R ³⁰ and R ³¹ are substituted with a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group or an acyloxy group. Also good. Y ⁻ represents a counter anion. ]

[In General Formula (5), R ³² , R ³³ , R ³⁴ and R ³⁵ each independently represents an alkyl group having 1 to 30 carbon atoms or an aralkyl group having 7 to 40 carbon atoms. R ³² , R ³³ , R ³⁴ and R ³⁵ may be substituted with a halogen atom, an alkoxy group, an aryloxy group, an alkoxycarbonyl group or an acyloxy group. Z represents a nitrogen atom or a phosphorus atom. Y ⁻ represents a counter anion. ]   The heat-sensitive recording material according to claim 1, wherein the diazonium salt and the molten salt are encapsulated in the same microcapsule.   The heat-sensitive recording material according to any one of claims 1 to 4, wherein the microcapsules comprise polyurethane and / or polyurea.