JPH09315008A - Thermal recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve coloring property, raw preservability, and stability of coloring image by using a compound shown by a specified formula as an electron accepting compound to be included in a thermal coloring layer. SOLUTION: In a thermal recording material formed by providing a thermal coloring layer which contains an electron donating colorless dye and an electron accepting compound a support body, a compound shown by a general formula is used as an electron accepting compound. In the formula R<1> is a hydrogen atom, an alkyl group or an aryl group, R<2> and R<4> are each a hydrogen atom, a cyano group, a carbamoyl group, an amino group, a urea group or a carbamoyl oxy group, R<3> is a hydrogen atom, an alkyl group, an aryl group, an alkyl oxy group, an alkyl oxy carbonyl group, carbamoyl group or the like. The electron accepting compound like this may be used together with another electron accepting compounds such as a phenol derivative, a phenol resin, a novolak resin, a metallic salt of aromatic carboxylic acid, an acid clay, and a bentonite.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording material, and more particularly to a heat-sensitive recording material having improved color developability, raw storability and stability of a color image.

[0002]

2. Description of the Related Art Recording materials using an electron-donating colorless dye and an electron-accepting compound are pressure-sensitive paper, thermal paper, photosensitive pressure-sensitive paper,
It is already well known as a heat-sensitive recording paper and a thermal transfer paper. For example, British Patent No. 2,140,449, US Patent Nos. 4,480,052 and 4,436,92
No. 0, JP-B-60-23992, JP-A-57-179
No. 836, No. 60-123556, No. 60-1235
No.57 and more. In particular, heat-sensitive recording materials are available in
-4160, Japanese Patent Publication No. 45-14039. These thermal recording systems have been applied to various fields such as facsimile, printer, and label, and the needs are expanding. However, since the heat-sensitive recording material has a drawback that fogging occurs due to a solvent and the like, and a color-forming body has a drawback that it undergoes discoloration due to oils and fats, chemicals, and the like,
In the fields of labels, slips, word processing paper, plotter paper, and the like, the commercial value has been significantly impaired.
The present inventors have investigated the electron-donating colorless dye and the electron-accepting compound, and have pursued the development of a good recording material and a recording material.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-sensitive recording material having good raw storability and stability of color image.

[0004]

The problem to be solved by the present invention is to provide a thermosensitive recording material comprising a support and a thermosensitive coloring layer containing an electron-donating colorless dye and an electron-accepting compound on the support. This is achieved by a heat-sensitive recording material characterized by using a compound represented by the following general formula I as the conductive compound. In the present invention, among the compounds represented by the general formula I, the compound represented by the general formula II is particularly preferable.

[0005]

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In the general formula I, R¹ Is a hydrogen atom, al
It represents a kill group or an aryl group. R ^Two , R^Four Are each
Independently hydrogen atom, cyano group, carbamoyl group, amino
Group, urea group, carbamoyloxy group, alkoxycal
Vamoyl group, nitro group, nitroso group, halogen atom,
Sylamino group, sulfonamide group, alkyloxycal
Bonyl group, acyl group, alkylsulfonyl group, aryl
Represents a sulfonyl group or a sulfamoyl group. R^Three Is water
Elementary atom, alkyl group, aryl group, alkyloxy group,
Alkyloxycarbonyl group, carbamoyl group, hydroxy
Group, amino group, urea group, carbamoyloxy group, al
Coxycarbamoyl group, acylamino group, alkylsulfur
Honyl group, arylsulfonyl group or sulfonamide
Represents a group. R in the general formula II¹ And R^Two Is defined above
It has the same meaning as the general formula I.

In the general formulas I and II, R ¹ , R ² and R
³ , R ⁴ and R ⁵ may further have a substituent. In the general formulas I and II, the alkyl group represented by R ¹ and R ³ is preferably an alkyl group having 1 to 10 carbon atoms, for example, methyl, ethyl, propyl, octyl, decyl, methoxyethyl, ethoxyethyl, methoxypropyl. , Methoxyethoxyethyl, ethoxycarbonylmethyl, 2
-Chloroethyl, 2- (1,3-dichloropropyl),
Examples include isopropyl, 3-heptyl, cyclopentyl, methylcyclohexyl, cyclohexyl, cyclodecyl, adamantyl, benzyl, phenethyl and the like.

In formulas I and II, the aryl group represented by R ¹ and R ³ is preferably an aryl group having 6 to 20 carbon atoms, and examples thereof include phenyl, tolyl, chlorophenyl, 1-naphthyl, 2-naphthyl and the like. Can be mentioned. In formulas I and II, the halogen atom represented by R ² and R ⁴ is preferably a chlorine atom or a bromine atom. In formulas I and II, the alkyloxy group represented by R ³ is preferably an alkyloxy group having 1 to 20 carbon atoms, for example, methoxy, ethoxy, propyloxy, methoxyethoxy, dodecyloxy, benzyloxy, paramethoxy. Benzyloxy and the like can be mentioned. In formulas I and II, the acyl group represented by R ² and R ⁴ is preferably an acyl group having 2 to 20 carbon atoms, and examples thereof include acetyl, caproyl, O-methyllactyl, cinnamoyl, palmitoyl, lauroyl and the like. .

In the general formulas I and II, R ² , R ³ and R
^The alkyloxycarbonyl group represented by ⁴ is preferably an alkyloxycarbonyl group having 2 to 20 carbon atoms, for example, methoxycarbonyl, ethoxycarbonyl,
t-Butyloxycarbonyl, benzyloxycarbonyl, decyloxycarbonyl and the like can be mentioned. In the general formulas I and II, the sulfamoyl group represented by R ² and R ⁴ is preferably a sulfamoyl group having 1 to 20 carbon atoms, for example, N-methylsulfamoyl, N, N-dimethylsulfamoyl, N -Phenyl sulfamoyl,
N-methyl-N-phenylsulfamoyl and the like can be mentioned. In formulas I and II, the amino group represented by R ² , R ³ , and R ⁴ is preferably an amino group having 1 to 20 carbon atoms, and examples thereof include dimethylamino, diethylamino, anilino, and N-benzyl-N-methyl. Amino etc. are mentioned.

In the general formulas I and II, R ² , R ³ and R
^The carbamoyl group represented by ⁴ has 2 to 20 carbon atoms.
Is preferred, and examples thereof include N, N-dimethylcarbamoyl, N-phenylcarbamoyl, N-benzyl-N-methylcarbamoyl and the like. In the general formulas I and II, the sulfonamide group represented by R ² , R ³ , and R ⁴ is preferably a sulfonamide group having 0 to 20 carbon atoms, and examples thereof include sulfonamide, N-methylsulfonamide, and N-phenyl. Examples thereof include enyl sulfonamide, N-benzyl sulfonamide, N-dodecyl sulfonamide and the like. In the general formulas I and II, R ² , R ³ , R
^The alkylsulfonyl group represented by ⁴ has 1 carbon atom.
The alkylsulfonyl group of -20 is preferable, and examples thereof include methylsulfonyl, benzylsulfonyl, 2-ethylhexylsulfonyl, phenethylsulfonyl and the like. In formulas I and II, the arylsulfonyl group represented by R ² , R ³ , and R ⁴ is preferably an arylsulfonyl group having 6 to 20 carbon atoms, and examples thereof include phenylsulfonyl, tolylsulfonyl, and phenoxyphenylsulfonyl. , Naphthylsulfonyl and the like.

In the general formulas I and II, R ² , R ³ and R
^The acylamino group represented by ⁴ has 2 to 20 carbon atoms.
Is preferably an acylamino group such as acetylamino,
Pivaloylamino, lauroylamino, stearoylamino, benzoylamino and the like can be mentioned. The general formula I,
In II, the urea group represented by R ² , R ³ and R ⁴ is preferably a urea group having 1 to 20 carbon atoms, and examples thereof include phenylurea, methylurea, p-methylphenylurea and benzylurea. . The general formula I,
In II, the carbamoyloxy group represented by R ² , R ³ and R ⁴ is preferably a carbamoyloxy group having 2 to 20 carbon atoms, and examples thereof include phenylcarbamoyloxy, methylcarbamoyloxy, p-methylphenylcarbamoyloxy. , Benzylcarbamoyloxy and the like.

In the general formulas I and II, R ² , R ³ and R
^{As the} alkoxycarbonylamino group represented by ⁴ ,
An alkoxycarbonylamino group having 2 to 20 carbon atoms is preferable, and examples thereof include benzyloxycarbonylamino, methoxycarbonylamino, and p-methylbenzyloxycarbonylamino.

Specific examples of the compounds represented by formulas I and II of the present invention are shown below, but the present invention is not limited thereto.

[0014]

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[0015]

[Chemical 6]

[0016]

[Chemical 7]

[0017]

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[0018]

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The electron-accepting compound of the present invention may be used alone or in combination of two or more kinds. Further, the compound represented by the general formula I or II according to the present invention and well-known phenol derivatives, phenol resins, novolac resins, metal-treated novolac resins, metal complexes, salicylic acid derivatives, aromatic carboxylic acids. You may use together with the electron-accepting compound, such as the metal salt, acid clay, and bentonite. Examples of these are Japanese Examined Patent Publication No. 40-9309.
Japanese Patent Publication No. 45-14039, JP-A No. 52-1404.
83, JP-A-48-51510, JP-A-57-21.
0886, JP-A-58-87089, JP-A-59-
11286, JP-A-60-176795, JP-A-6
1-95988, JP-A-63-65979, JP-A-6-72984, and JP-A-7-278098.

Examples of some of these are 4-t-butylphenol, 4-phenylphenol, 2,2'-dihydroxybiphenyl, 2,2-bis (4-hydroxyphenyl) propane (bisphenol. A) 2,2-bis- (4-hydroxyphenyl) butane, 1,1-bis (4-hydroxyphenyl) cyclohexane, bis- (3-phenyl-4-hydroxyphenyl) sulfone,
4-hydroxyphenyl-3 ', 4'-dimethylphenylsulfone, 4- (4-isopropoxyphenylsulfonyl) phenol, 4,4'-dihydroxydiphenylsulfide, 1,4-bis- (3'- (4′-hydroxycumyl)) benzene, 1,3-bis- (3 ′-(4′-hydroxycumyl)) benzene, 4,4′-thiobis (2-t-butyl-5-methylphenol) ,
1,1,3-tris (2-methyl-4-hydroxy-5
-Tert-butylphenyl) butane, 1,1-bis- (4-hydroxy-3-methyl-6-tert-butylphenyl) butane, 4,4'-dihydroxydiphenylsulfone, 4
-Benzylhydroxybenzoate, 3-phenyl-5-
(Α, α-dimethylbenzyl) salicylic acid, 3-cumyl-5-t-octylsalicylic acid, 3,5-di-t-butylsalicylic acid, 3-phenyl-5-t-octylsalicylic acid, 3-methyl-5-α -Methylbenzylsalicylic acid, 3-methyl-5-cumylsalicylic acid, 3,5-bis (α-methylbenzyl) salicylic acid, 3-cumyl-5-
Phenylsalicylic acid, 5-n-octadecylsalicylic acid, 4-pentadecylsalicylic acid, 3,5-bis (α,
α-dimethylbenzyl) salicylic acid, 3,5-bis-t
-Octylsalicylic acid, 4-β-dodecyloxyethoxysalicylic acid, 4-methoxy-6-dodecyloxysalicylic acid, 4-β-phenoxyethoxysalicylic acid, 4-
β-p-ethylphenoxyethoxysalicylic acid, 4-β
-P-methoxyphenoxyethoxysalicylic acid, 4-octyloxycarbonylaminosalicylic acid, 2-phenoxymethylcarbonylaminobenzoic acid, 4,4′-bis (N ′-(p-toluenesulfonylureido) diphenylmethane, and the like, and the like. And metal salts.

The above-mentioned electron-accepting compound is preferably used in an amount of 50 to 800% by weight of the electron-donating colorless dye,
More preferably, it is 100 to 500% by weight. When two or more electron-accepting compounds are used in combination, the compound represented by the general formula I or the general formula II according to the present invention is 30% or more,
It is particularly preferable that the content is 50% or more.

As the electron-donating colorless dye that can be used in the present invention, it is possible to use conventionally known ones. Specifically, triphenyl methanephthalide compounds, fluoran compounds, phenothiazine compounds, indolylphthalide compounds, leuco auramine compounds, rhodamine lactam compounds, triphenylmethane compounds, triazene compounds, spiropyrans. Examples thereof include various compounds such as system compounds, fluorene compounds, pyridine compounds and pyrazine compounds. Specific examples of the phthalides include US Reissue Patent No. 23,024, US Patent Nos. 3,491,111, and 3,491,112.
No. 3, ibid. 3, 491, 116 and ibid. 3, 509,
174, specific examples of fluoranes are disclosed in US Pat. No. 3,62.
No. 4, 107, No. 3, 627, 787, No. 3, 6
No. 41, 011, No. 3, 462, 828, No. 3,
681, 390, 3,920,510, 3,959,571, specific examples of spiropyrans are U.S. Pat. No. 3,971,808, pyridine compounds and pyrazine compounds are U.S. Pat. No. 3,775,424, No. 3,853,869, No. 4,246,318, and specific examples of fluorene compounds are described in JP-A-63-94878. In the present invention, the electron donating colorless dye represented by the following general formula III is particularly preferable.

[0023]

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In the formula, R ⁵ and R ⁶ each independently represent a hydrogen atom, an alkyl group or an aryl group, and R ⁵ and R ⁶ may combine with each other to form a heterocycle. R ⁷ and R ⁸ each independently represent a hydrogen atom, an alkyl group or an aryl group. R ⁹ represents a hydrogen atom, an alkyl group, an alkyloxy group or a halogen atom.

In the above general formula III, R ⁵ , R ⁶ ,
The substituents of R ⁷ , R ⁸ and R ⁹ may further have a substituent. In the general formula III, R ⁵ , R ⁶ , R
^The alkyl group represented by ⁷ , R ⁸ and R ⁹ has 1 carbon atom.
Preferred are alkyl groups of 10 to 10, for example, methyl, ethyl, propyl, octyl, decyl, methoxyethyl, ethoxyethyl, methoxypropyl, methoxyethoxyethyl, ethoxycarbonylmethyl, 2-chloroethyl,
2- (1,3-dichloropropyl), isopropyl, 3
-Heptyl, cyclopentyl, methylcyclohexyl,
Cyclohexyl, cyclodecyl, adamantyl, benzyl, phenethyl and the like can be mentioned. In the general formula III, the aryl group represented by R ⁵ , R ⁶ , R ⁷ , and R ⁸ is preferably an aryl group having 6 to 20 carbon atoms, and examples thereof include phenyl, tolyl, chlorophenyl, 1-naphthyl,
2-naphthyl and the like can be mentioned. In the general formula III, the halogen atom represented by R ⁹ is preferably a chlorine atom or a bromine atom. In the general formula III, the alkyloxy group represented by R ⁹ is preferably an alkyloxy group having 1 to 20 carbon atoms, and examples thereof include methoxy, ethoxy, propyloxy, methoxyethoxy, dodecyloxy, benzyloxy and paramethoxybenzyl. Oxy etc. are mentioned.

Illustrating some of these, 2-arylamino-3-H, halogen, alkyl or alkyloxy-6-substituted aminofluoranes are preferred. Specific examples include 2-anilino-3-methyl-6-diethylaminofluorane, 2-anilino-3-methyl-6- (N
-Cyclohexyl-N-methylamino) fluoran, 2
-P-chloroanilino-3-methyl-6-dibutylaminofluorane, 2-anilino-3-chloro-6-diethylaminofluorane, 2-anilino-3-methyl-6-
(N-ethyl-N-isoamylamino) fluoran, 2
-Anilino-3-methyl-6- (N-ethyl-N-dodecylamino) fluorane, 2-anilino-3-methoxy-6-dibutylaminofluorane, 2-o-chloroanilino-6-dibutylaminofluorane, 2 -Anilino-
3-pentadecyl-6-diethylaminofluorane, 2
-Anilino-3-ethyl-6-dibutylaminofluorane, 2-o-toluidino-3-methyl-6-diisopropylaminofluorane, 2-anilino-3-methyl-6
-(N-isobutyl-N-ethylamino) fluorane,
2-anilino-3-methyl-6- (N-ethyl-N-tetrahydrofurfurylamino) fluorane, 2-anilino-3-chloro-6- (N-ethyl-N-isoamylamino) fluorane, 2-anilino- 3-methyl-6-
(N-methyl-N-γ-ethoxypropylamino) fluorane, 2-anilino-3-methyl-6-N-ethyl-
N-γ-ethoxypropylaminofluorane, 2-anilino-3-methyl-6- (N-ethyl-N-γ-propoxypropylamino) fluorane, 2-anilino-3-
Methyl-6- (N-methyl-N-propylamino) fluorane and the like can be mentioned.

2-anilino-3-methyl-6-dialkylaminofluorane is particularly preferred, and 2-anilino-
3-methyl-6-dibutylaminofluoran, 2-anilino-3-methyl-6- (N-ethyl-N-propylamino) fluoran, 2-anilino-3-methyl-6-dihexylaminofluoran, 2-anilino -3-Methyl-6-diethylaminofluoran, 2-anilino-3-
Methyl-6- (N-ethyl-N-isoamyl) aminofluorane and 2-anilino-3-methyl-6- (N-ethyl-N-isobutyl) aminofluorane are particularly preferred.

As the sensitizer used in the present invention, those known as conventionally known sensitizers can be used. Specific examples thereof include aromatic ethers (particularly benzyl ethers, di (substituted phenoxy) alkanes), aromatic esters, oxalic acid esters and / or aliphatic amides, ureas or aromatic amides or ureas.
More specifically, compounds described in JP-A-58-57989, JP-A-58-87094, JP-A-63-39375 and the like can be mentioned.

As the binder used in the present invention,
A compound that is soluble in 5% by weight or more in water at 25 ° C. is preferable, and specifically, polyvinyl alcohol (including modified polyvinyl alcohol such as carboxy-modified, itaconic acid-modified, maleic acid-modified, and silica-modified), methyl cellulose, carboxy Examples thereof include methyl cellulose, starches (including modified starch), gelatin, gum arabic, casein, styrene-maleic anhydride copolymer hydrolyzate, polyacrylamide, and saponified products of vinyl acetate-polyacrylic acid copolymer. These binders are used not only during dispersion but also for the purpose of improving the coating strength. For this purpose, styrene / butadiene copolymer, vinyl acetate copolymer, acrylonitrile / butadiene copolymer, acrylic resin are used. Methyl acid-butadiene copolymer,
A latex-based binder of a synthetic polymer such as polyvinylidene chloride may be used in combination. If necessary, a crosslinking agent for an appropriate binder may be added according to the type of the binder.

Examples of the pigment used in the present invention include calcium carbonate, barium sulfate, lithopone, wax, kaolin, silica and amorphous silica. As the metal soap, higher fatty acid metal salts are used, and examples thereof include zinc stearate, calcium stearate, and aluminum stearate. Further, a surfactant, an antistatic agent, an ultraviolet absorber, an antifoaming agent, a conductive agent, a fluorescent dye, a coloring dye, and the like may be added as necessary.

The support used in the present invention should be selected from paper or coated paper in which pigment or latex is coated on the surface of paper, resin laminated paper, synthetic paper made from polyolefin resin, plastic film and the like. You can

If desired, a protective layer may be provided on the thermosensitive coloring layer. As the protective layer, those known as a protective layer for heat-sensitive recording materials can be used. Further, if necessary, a back coat layer may be provided on the surface of the support of the thermosensitive recording material opposite to the thermosensitive coloring layer. As the back coat layer, those known as the back coat layer of the thermal recording material can be used.

[0033]

【Example】

(Synthesis example) 3-Cyano-1-decyl-4-methyl-2-oxo-1
Synthesis of H, 2H dihydropyridine 24 g of decylamine was dissolved in 31.8 g of 28% methanol solution of sodium methoxide, and 19.7 g of ethyl acetoacetate and 15.0 g of methyl cyanoacetate were added to this solution. This mixed liquid was reacted at 60 ° C. for 6 hours. After the reaction was completed, the reaction solution was added to about 200 cc of an aqueous solution of about 10% hydrochloric acid to be neutralized. The obtained crystals were separated by filtration and recrystallized from methanol to give 3-cyano-1-decyl-4-
Methyl-2-oxo-1H, 2H dihydropyridine 1
0.0 g was obtained. The melting point was 136-138 ° C.

Example 1 As an electron-donating colorless dye,
2-anilino-3-methyl-6-dibutylaminofluorane, 3-cyano-1-ethyl-4-methyl-2-oxo-1H, 2Hdihydropyridine as an electron-accepting compound, and di (p) oxalate as a sensitizer. -Methylbenzyl) ester, 20 g each of which was dispersed with 100 g of a 5% aqueous solution of polyvinyl alcohol (Kuraray PVA-105) in a ball mill all day and night so that the average particle size was 1.5 μm or less, and each dispersion was obtained. Further, 80 g of calcium carbonate was dispersed with 160 g of a 0.5% sodium hexametaphosphate solution by a homogenizer to obtain a pigment dispersion liquid. 5 g of each of the dispersions prepared as described above was used as an electron-donating colorless dye dispersion, 5 g of an electron-accepting compound dispersion, 10 g of an oxalic acid di (p-methylbenzyl) ester dispersion, and 5 g of a calcium carbonate dispersion. Then, 3 g of a 21% zinc stearate emulsion was added to obtain a heat-sensitive coating liquid. This thermosensitive coloring layer coating solution is applied on a high-quality paper having a basis weight of 50 g / m ² by using a wire bar so that the dry weight of the coating layer is 5 g / m ² , and dried at 50 ° C. for 1 minute. I got

Example 2 3-Cyano-1-of Example 1
Instead of using ethyl-4-methyl-2-oxo-1H, 2Hdihydropyridine, a heat-sensitive coating solution was prepared using 3-cyano-1-decyl-4-methyl-2-oxo-1H, 2Hdihydropyridine. A thermal recording paper was obtained by the same method except for the above.

Example 3 3-Cyano-1-of Example 1
Instead of using ethyl-4-methyl-2-oxo-1H, 2H dihydropyridine, 3-carbonylamino-
A heat-sensitive recording paper was obtained by the same method except that the heat-sensitive coating liquid was prepared by using 1-ethyl-4-methyl-2-oxo-1H and 2H dihydropyridine.

Example 4 3-Cyano-1-of Example 1
Instead of using ethyl-4-methyl-2-oxo-1H, 2Hdihydropyridine, a heat-sensitive coating solution was prepared by using 3-cyano-1-ethyl-4-phenyl-2-oxo-1H, 2Hdihydropyridine. A thermal recording paper was obtained by the same method except for the above.

Example 5 3-Cyano-1-of Example 1
Instead of using ethyl-4-methyl-2-oxo-1H, 2Hdihydropyridine, 3-cyano-1-ethyl-4-phenyl-2-oxo-1H, 2Hdihydropyridine and 2,2-bis (4-hydroxy) A thermosensitive recording paper was obtained by the same method except that a thermosensitive coating liquid was prepared using a weight mixture such as phenyl) propane.

(Example 6) 3-cyano-1-of Example 1
Instead of using ethyl-4-methyl-2-oxo-1H, 2Hdihydropyridine, 3-cyano-1-ethyl-4-phenyl-2-oxo-1H, 2Hdihydropyridine and 4-β-p-methoxyphenoxy are used. A heat-sensitive recording paper was obtained by the same method except that the heat-sensitive coating liquid was prepared using a weight mixture such as cyethoxysalicylic acid.

Comparative Example 1 3-Cyano-1-of Example 1
Heat-sensitive by the same method except that a heat-sensitive coating solution was prepared by using 2,2-bis (4-hydroxyphenyl) propane instead of using ethyl-4-methyl-2-oxo-1H, 2Hdihydropyridine. I got the recording paper.

The thermal recording paper obtained as described above is
The surface was treated with a calender, and the smoothness was adjusted to a Beck smoothness of 300 ± 50 seconds to obtain a heat-sensitive recording material. To test the plasticizer resistance of heat-sensitive recording paper, use a Kyocera printing tester to print at a printing energy of 30 mJ / mm ² and lay the color on a commercially available polyvinyl chloride sheet. Discoloration (discoloration)
Was visually evaluated. In the heat resistance test, the image density was measured after the heat-sensitive paper, which was similarly printed and colored, was allowed to stand under high temperature drying conditions of 60 ° C. and 30% RH for 24 hours. Table 1 shows the above results.

[0042]

[Table 1]

[0043]

As is clear from the results shown in Table 1, the heat-sensitive recording material of the present invention does not cause fog coloration or decolorization of the color-developed portion due to the plasticizer, and has excellent heat resistance. ing.

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Claims (3)

[Claims] 1. A thermosensitive recording material comprising a support and a thermosensitive coloring layer containing an electron-donating colorless dye and an electron-accepting compound, wherein the electron-accepting compound is a compound represented by the following general formula I: A heat-sensitive recording material characterized by: Embedded image In the formula, R ¹ represents a hydrogen atom, an alkyl group or an aryl group. R ² and R ⁴ are each independently a hydrogen atom, cyano group, carbamoyl group, amino group, urea group, carbamoyloxy group, alkoxycarbamoyl group, nitro group, nitroso group, halogen atom, acylamino group, sulfonamide group, alkyloxy group. It represents a carbonyl group, an acyl group, an alkylsulfonyl group, an arylsulfonyl group or a sulfamoyl group. R ³ is a hydrogen atom, an alkyl group, an aryl group, an alkyloxy group, an alkyloxycarbonyl group, a carbamoyl group, a hydroxyl group, an amino group, a urea group, a carbamoyloxy group, an alkoxycarbamoyl group, an acylamino group, an alkylsulfonyl group, an arylsulfonyl group. Alternatively, it represents a sulfonamide group. 2. The electron-accepting compound is represented by the following general formula II:
The heat-sensitive recording material according to claim 1, which is a compound represented by: Embedded image In the formula, R ¹ represents a hydrogen atom, an alkyl group or an aryl group. R ² is a hydrogen atom, cyano group, carbamoyl group, amino group, urea group, carbamoyloxy group, alkoxycarbamoyl group, nitro group, nitroso group, halogen atom, acylamino group, sulfonamide group, alkyloxycarbonyl group, acyl group, It represents an alkylsulfonyl group, an arylsulfonyl group or a sulfamoyl group. 3. The electron donating colorless dye is represented by the following general formula I:
2. A compound represented by II.
Alternatively, the heat-sensitive recording material described in 2. Embedded image In the formula, R ⁵ and R ⁶ each independently represent a hydrogen atom, an alkyl group or an aryl group, and R ⁵ and R ⁶ may combine with each other to form a heterocycle. R ⁷ and R ⁸ each independently represent a hydrogen atom, an alkyl group or an aryl group. R ⁹
Represents a hydrogen atom, an alkyl group, an alkyloxy group or a halogen atom.