JPH1016402A - Heat-sensitive recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve shelf stability and coloring properties by using a compound represented by a specified formula as an electron receptive compound in a heat-sensitive recording material with a heat recording layer containing an electron receptive colorless dye and an electron receptive compound. SOLUTION: In a heat-sensitive recording material used as a pressure-sensitive paper, a heat-sensitive paper or a photosensitive and pressure-sensitive paper and the like and having a heat-sensitive recording layer containing an electron donative colorless dye and an electron receptive compound on a substrate, a compound represented by a formula is used as the electron acceptive compound. In the formula, R<1> -R<3> represent hydrogen atom, alkyl, aryl, cyano, nitro or the like, and R<1> -R<2> can be bonded together to form a ring. The compounds represented by the formula can be used alone or in combination of at least two kinds, and the compound represented by the formula can be used combinedly with the electron receptive compound such as a phenol derivative phenol resin, novolak resin, metallized novolak resin, a metal complex or the like.

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 storage stability, 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 include pressure-sensitive paper, heat-sensitive 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
No.-4160 and 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 studied each of an electron-donating colorless dye and an electron-accepting compound, and have pursued the development of good recording material materials and recording materials.

[0003]

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

[0004]

An object of the present invention is to provide a thermosensitive recording material comprising a support and a thermosensitive recording layer containing a colorless electron-donating dye and an electron-accepting compound. This was achieved by a heat-sensitive recording material using a compound represented by the following general formula I as a receptive compound.

[0005]

Embedded image

In the formula, R ¹ , R ² and R ³ represent a hydrogen atom, an alkyl group, an aryl group, a cyano group, a nitro group, a halogen atom, an acylamino group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyl group, an alkylsulfonyl. Represents a group, an arylsulfonyl group, a sulfonamide group, an alkoxy group, an aryloxy group, a carbamoyl group, an amino group, a ureido group, a carbamoyloxy group, a sulfamoyl group, an alkylthio group, or an arylthio group.
R ¹ and R ² may combine to form a ring.

The substituents of R ¹ , R ² and R ³ in the general formula I may further have a substituent.

In the above general formula I, R ¹ , R ² , R ³
The alkyl group represented by 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), isopropyl, 3-heptyl, cyclopentyl, methylcyclohexyl, cyclohexyl, cyclodecyl, adamantyl, benzyl, phenethyl and the like.

In the general formula I, R ¹ , R ² , R ³
The aryl group represented by is preferably an aryl group having 6 to 20 carbon atoms, and examples thereof include phenyl, tolyl, chlorophenyl, 1-naphthyl, and 2-naphthyl.

In the above general formula I, R ¹ , R ² , R ³
Is preferably a chlorine atom or a bromine atom.

In the above formula I, R ¹ , R ² , R ³
The alkoxy group represented by is preferably an alkoxy group having 1 to 20 carbon atoms, and examples thereof include methoxy, ethoxy, propyloxy, methoxyethoxy, dodecyloxy, benzyloxy, and paramethoxybenzyloxy.

In the general formula I, R ¹ , R ² , R ³
The aryloxy group represented by the formula has 6 to 20 carbon atoms.
Aryloxy groups are preferred, for example, phenoxy, p
-Methoxyphenoxy, naphthyloxy and the like.

In the general formula I, R ¹ , R ² , R ³
The acyl group represented by is preferably an acyl group having 2 to 20 carbon atoms, and examples thereof include acetyl, caproyl, O-methyllactyl, cinnamoyl, palmitoyl, and lauroyl.

In the above general formula I, R ¹ , R ² , R ³
The alkoxycarbonyl group represented by
~ 20 alkoxycarbonyl groups are preferred, and examples include methoxycarbonyl, ethoxycarbonyl, t-butoxycarbonyl, benzyloxycarbonyl, decyloxycarbonyl and the like.

In the above general formula I, R ¹ , R ² , R ³
The aryloxycarbonyl group represented by is preferably an aryloxycarbonyl group having 7 to 20 carbon atoms,
For example, phenoxycarbonyl, p-methoxyphenoxycarbonyl, naphthyloxycarbonyl and the like can be mentioned.

In the above formula I, R ¹ , R ² , R ³
As the sulfamoyl group represented by
Is preferred, for example, N-methylsulfamoyl, N, N-dimethylsulfamoyl, N-phenylsulfamoyl, N-methyl-N-phenylsulfamoyl and the like are preferable.

In the above general formula I, R ¹ , R ² , R ³
As the sulfonamide group represented by
Is preferred, for example, benzenesulfonamide, N-methylbenzenesulfonamide, methanesulfonamide and the like.

In the above general formula I, R ¹ , R ² , R ³
The amino group represented by is preferably an amino group having 1 to 20 carbon atoms, for example, dimethylamino, diethylamino, anilino, N-benzyl-N-methylamino and the like.

In the above formula I, R ¹ , R ² , R ³
The carbamoyl group represented by is preferably a carbamoyl group having 2 to 20 carbon atoms, for example, N, N-dimethylcarbamoyl, N-phenylcarbamoyl, N-benzyl-N-methylcarbamoyl and the like.

In the above general formula I, R ¹ , R ² , R ³
As the alkylsulfonyl group represented by
Preferred are 20 alkylsulfonyl groups, for example, methylsulfonyl, benzylsulfonyl, 2-ethylhexylsulfonyl, phenethylsulfonyl and the like.

In the general formula I, R ¹ , R ² , R ³
The arylsulfonyl group represented by
Preferred are 20 arylsulfonyl groups, for example, phenylsulfonyl, tolylsulfonyl, phenoxyphenylsulfonyl, naphthylsulfonyl and the like.

In the above general formula I, R ¹ , R ² , R ³
The acylamino group represented by is preferably an acylamino group having 2 to 20 carbon atoms, for example, acetylamino, pivaloylamino, lauroylamino, stearoylamino, benzoylamino and the like.

In the above general formula I, R ¹ , R ² , R ³
The urea group represented by is preferably a ureido group having 1 to 20 carbon atoms, for example, phenylureido, methylureide, p-methylphenylureide, benzylureide and the like.

In the general formula I, R ¹ , R ² , R ³
Is preferably an alkylthio group having 1 to 20 carbon atoms, for example, methylthio, butylthio, methoxyethylthio and the like.

In the above general formula I, R ¹ , R ² , R ³
The arylthio group represented by is preferably an alkylthio group having 6 to 20 carbon atoms, for example, phenylthio, p-
Methylphenylthio, methoxyphenylthio and the like are preferred.

In the general formula I, R ¹ , R ² , R ³
As the carbamoyloxy group represented by
20 carbamoyloxy groups are preferred, for example, phenylcarbamoyloxy, methylcarbamoyloxy, p
-Methylphenylcarbamoyloxy, benzylcarbamoyloxy and the like are preferred.

In formula (I), when R ¹ and R ² form a ring, it is preferable to form a 5- or 6-membered ring. For example, a benzene ring, a cyclohexane ring, a cyclopentane ring and the like are preferable. These rings may further have a substituent such as an alkyl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, and an amino group.

Specific examples of the compound represented by the general formula I of the present invention are shown below, but the present invention is not limited thereto.

[0029]

Embedded image

[0030]

Embedded image

The compounds represented by the general formula I of the present invention may be used alone or in combination of two or more. Further, a compound represented by the general formula I according to the present invention, and a well-known phenol derivative, a phenol resin, a novolak resin,
A metal-treated novolak resin, a metal complex, a salicylic acid derivative, a metal salt of an aromatic carboxylic acid, an acid clay, an electron-accepting compound such as bentonite may be used in combination. These examples are disclosed in Japanese Patent Publication No. 40-9309, Japanese Patent Publication No.
No. 14039, Japanese Patent Application Laid-Open No. 52-140483,
JP-A-48-51510, JP-A-57-2108
No. 86, JP-A-58-87089, JP-A-5-87089
JP-A-9-11286, JP-A-60-176795, JP-A-61-95988, JP-A-63-65
979, JP-A-6-72984, JP-A-7-72984
It is described in detail in, for example, JP-A-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 electron-accepting compound used in the heat-sensitive recording material of the present invention is an electron-donating colorless dye of 50 to 800.
% By weight, more preferably 10% by weight.
0 to 500% by weight. When two or more electron-accepting compounds are used in combination, it is preferable that the compound represented by the general formula I according to the present invention be contained in an amount of 30% or more, particularly 50% or more.

Examples of the electron-donating colorless dyes used in the present invention include triphenylmethanephthalide compounds, fluoran compounds, phenothiazine compounds, indolylphthalide compounds, leucouramine compounds, rhodamine lactam compounds. Various compounds such as compounds, triphenylmethane compounds, triazene compounds, spiropyran compounds, fluorene compounds, pyridine compounds and pyrazine compounds can be mentioned. Specific examples of phthalides are described in U.S. Pat. No. Re. 23,024, U.S. Pat.
491,111, 3,491,112, 3,491,116 and 3,3
509,174, and specific examples of fluorans are described in U.S. Pat. Nos. 3,624,107 and 3,627,
No. 787, No. 3,641,011, No. 3,462,828, No. 3,681,39
0, 3,920,510, 3,959,571, and specific examples of spiropyrans are described in US Pat. No. 3,971,808, pyridine-based and pyrazine-based compounds. The compounds are described in U.S. Pat. No. 3,775,4.
No. 24, 3,853,869, 4,246,318, and specific examples of fluorene compounds are described in detail in JP-A-63-94878. . Of these, an electron-donating colorless dye represented by the general formula II is particularly preferred.

[0035]

Embedded image

In the formula, R ⁴ , R ⁵ , R ⁶ and R ⁷ each independently represent a hydrogen atom, an alkyl group or an aryl group. R ⁸
Represents a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom. Further, R ⁴ and R ⁵ , or R ⁶ and R ⁷ may be bonded to each other to form a ring.

In the general formula II, R ⁴ , R ⁵ , R
The substituents of ⁶ , R ⁷ and R ⁸ may further have a substituent.

In the general formula II, R ⁴ , R ⁵ , R
^The alkyl group represented by ⁶ , R ⁷ and R ⁸ 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, methylcyclohexanyl, cyclohexanyl, cyclodecanyl, adamantanyl and the like.

In the above general formula II, R ⁴ , R ⁵ , R
^The aryl group represented by ⁶ , R ⁷ and R ⁸ has 6 carbon atoms.
To 20 aryl groups are preferable, and examples thereof include phenyl, tolyl, chlorophenyl, 1-naphthyl and 2-naphthyl.

In the general formula II, the halogen atom represented by R ⁸ is preferably a chlorine atom or a bromine atom.

In the general formula II, the alkoxy group represented by R ⁸ is preferably an alkoxy group having 1 to 20 carbon atoms, such as methoxy, ethoxy, propyloxy, methoxyethoxy, dodecyloxy, benzyloxy, p- Methoxybenzyloxy and the like can be mentioned.

Among the electron-donating colorless dyes represented by the general formula II, 2-arylamino-3-H, halogen,
Alkyl or alkoxy-6-substituted aminofluorans are preferred. Examples of the electron-donating colorless dye represented by the general formula II include 2-anilino-3-methyl-6-diethylaminofluoran and 2-anilino-3-methyl-6.
-(N-cyclohexyl-N-methylamino) fluoran, 2-p-chloroanilino-3-methyl-6-dibutylaminofluoran, 2-anilino-3-chloro-6-
Diethylaminofluoran, 2-anilino-3-methyl-6- (N-ethyl-N-isoamylamino) fluoran, 2-anilino-3-methyl-6- (N-ethyl-N
-Dodecylamino) fluoran, 2-anilino-3-methoxy-6-dibutylaminofluoran, 2-o-chloroanilino-6-dibutylaminofluoran, 2-anilino-3-pentadecyl-6-diethylaminofluoran, 2- Anilino-3-ethyl-6-dibutylaminofluoran, 2-o-toluidino-3-methyl-6-diisopropylaminofluoran, 2-anilino-3-methyl-6- (N-isobutyl-N-ethylamino) Fluoran, 2-anilino-3-methyl-6- (N-ethyl-
N-tetrahydrofurfurylamino) fluoran, 2-
Anilino-3-chloro-6- (N-ethyl-N-isoamylamino) fluoran, 2-anilino-3-methyl-
6- (N-methyl-N-γ-ethoxypropylamino)
Fluoran, 2-anilino-3-methyl-6-N-ethyl-N-γ-ethoxypropylaminofluoran, 2-
Anilino-3-methyl-6- (N-ethyl-N-γ-propoxypropylamino) fluoran, 2-anilino-
3-methyl-6- (N-methyl-N-propylamino)
Fluoran and the like.

Particularly, 2-anilino-3-methyl-6-dialkylaminofluoran is preferable, 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) aminofluoran and 2-anilino-3-methyl-6- (N-ethyl-N-isobutyl) aminofluoran are preferred.

Known sensitizers can be used in the heat-sensitive recording material of the present invention. Examples of sensitizers are disclosed in
Compounds disclosed in JP-A-8-57989, JP-A-58-87094, JP-A-63-39375 and the like can be mentioned. Specifically, aromatic ethers (particularly, benzyl ethers, di (substituted phenoxy) alkanes), aromatic esters, oxalic esters, aliphatic amides, aliphatic ureas, aromatic amides, aromatic ureas, etc. Representative.

As the binder used in the heat-sensitive recording material of the present invention, a compound which is soluble in water at 25 ° C. in an amount of 5% by weight or more is preferable. Specifically, polyvinyl alcohol (carboxy-modified, itaconic-acid-modified, maleic acid-modified) Modified, silica-modified and other modified polyvinyl alcohols), methylcellulose, carboxymethylcellulose, starches (including modified starch), gelatin, gum arabic, casein, styrene-maleic anhydride copolymer hydrolyzate, polyacrylamide, acetic acid Saponified vinyl-polyacrylic acid copolymers and the like can be mentioned. These binders are used not only at the time of dispersion but also for the purpose of improving the strength of the coating film. For this purpose, styrene-butadiene copolymer, vinyl acetate copolymer, acrylonitrile-butadiene copolymer, acrylic Latex binders of synthetic polymers such as methyl acid-butadiene copolymer and polyvinylidene chloride can also 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 heat-sensitive recording material of the present invention include calcium carbonate, barium sulfate, lithopone, wax, kaolin, silica, and amorphous silica.

Examples of the metal soap used in the heat-sensitive recording material of the present invention include zinc stearate, calcium stearate, aluminum stearate and the like.

The heat-sensitive recording material of the present invention may optionally contain
A wax, a surfactant, an antistatic agent, an ultraviolet absorber, an antifoaming agent, a conductive agent, a fluorescent dye, a coloring dye and a pigment may be added.

Examples of the support used in the heat-sensitive recording material of the present invention include papers such as acidic paper and neutral paper, coated paper coated with pigments and the like, plastic film laminated paper obtained by laminating a plastic film such as polyethylene, Examples include synthetic paper made from polypropylene or polyester resin, and plastic films such as polyethylene terephthalate and polyethylene naphthalate.

In the method for producing a heat-sensitive recording material of the present invention, an electron-donating colorless dye, an electron-accepting compound, a sensitizer and the like are first mixed with a water-soluble polymer aqueous solution such as polyvinyl alcohol using a ball mill or a sand mill for several microns. Disperse to: The sensitizer is added to either or both of the electron-donating colorless dye and the electron-accepting compound, and is dispersed at the same time, or in some cases, a eutectic with the electron-donating colorless dye or the electron-accepting compound is prepared in advance. , May be dispersed. Next, these dispersions are mixed, and if necessary, a pigment, a surfactant, a binder, a metal soap, a wax, an antioxidant, an ultraviolet absorber and the like are added to obtain a coating solution for a heat-sensitive recording layer. The obtained heat-sensitive recording layer coating solution is coated on a support,
dry. The coating amount of the coating solution for the heat-sensitive recording layer is preferably from 1 to 15 g / m ² in a state where the coating solution layer is dried, and from ² to 10 g.
/ M ² is particularly preferred. Then, if necessary, smoothness is imparted by a calendering process to obtain a thermosensitive recording material.

The heat-sensitive recording material of the present invention includes a protective layer on the heat-sensitive recording layer, an undercoat layer between the support and the heat-sensitive recording layer, and a backcoat on the surface of the support opposite to the heat-sensitive recording layer. Layers can be provided. All of these layers can be provided using a known method.

Hereinafter, the present invention will be described in detail with reference to Examples of the present invention, but the present invention is not limited thereto.

[0053]

【Example】

(Synthesis Example) Synthesis of 7-hexyloxy-4-hydroxycoumarin 22.4 g of 5-hexyloxy-2-acetophenol
Was dissolved in 200 ml of tetrahydrofuran. 6.0 g of sodium hydride was slowly added to this solution at 30-50 ° C. After the addition, 35.4 g of diethyl carbonate was added, and 2
Refluxed for hours. After cooling the reaction solution, methanol was added slowly, and the mixture was further refluxed for 1 hour. 19.6 g of the desired product, 7-hexyloxy-4-hydroxycoumarin, was obtained. Yield 75%.

Example 1 2 as an electron donating colorless dye
-Anilino-3-methyl-6-dibutylaminofluoran, 6-methyl-4-hydroxy-2H-pyran-2-one as an electron accepting compound, di (p-methylbenzyl) oxalate as a sensitizer, 20g each for 100
g of 5% polyvinyl alcohol (Kuraray PVA-10)
5) Dispersed together with the aqueous solution in a ball mill all day and night to reduce the average particle size to 1.5 μm or less to obtain each dispersion. Also, 80 g of calcium carbonate was added to sodium hexametaphosphate 0.5%
The mixture was dispersed with a homogenizer together with 160 g of the solution to obtain a calcium carbonate dispersion. 5 g of an electron-donating colorless dye dispersion, 10 g of an electron-accepting compound dispersion, 10 g of di (p-methylbenzyl) oxalate dispersion, and 5 g of calcium carbonate dispersion were prepared as described above. And 3 g of a 21% zinc stearate emulsion was added to obtain a coating solution for a heat-sensitive recording layer. This solution was applied on a high-quality paper having a basis weight of 50 g / m ² using a wire bar so that the dry weight of the coating layer became 5 g / m ² ,
For 1 minute to obtain a heat-sensitive recording material.

[Example 2] 6-Methyl-4- of Example 1
Instead of using hydroxy-2H-pyran-2-one, 6-phenyl-4-hydroxy-2H-pyran-2
A heat-sensitive recording material was obtained in the same manner except that a coating solution for a heat-sensitive recording layer was prepared using -ON.

Example 3 6-Methyl-4- of Example 1
A heat-sensitive recording material was obtained in the same manner except that a coating solution for a heat-sensitive recording layer was prepared using 4-hydroxycoumarin instead of using hydroxy-2H-pyran-2-one.

Example 4 6-Methyl-4- of Example 1
A heat-sensitive recording material was obtained in the same manner except that a coating solution for a heat-sensitive recording layer was prepared using 7-hexyloxy-4-hydroxycoumarin instead of using hydroxy-2H-pyran-2-one.

Example 5 6-Methyl-4- of Example 1
Instead of using hydroxy-2H-pyran-2-one, 6-methyl-4-hydroxy-2H-pyran-2-one
A heat-sensitive recording material was obtained in the same manner except that an equivalent mixture of ON and 2,2-bis (4-hydroxyphenyl) propane was used to prepare a coating solution for the heat-sensitive recording layer.

Comparative Example 1 6-Methyl-4- of Example 1
A heat-sensitive recording material is prepared in the same manner except that a coating solution for a heat-sensitive recording layer is prepared using 2,2-bis (4-hydroxyphenyl) propane instead of using hydroxy-2H-pyran-2-one. I got

The heat-sensitive recording material obtained as described above is subjected to a surface treatment with a calender, and has a Beck smoothness of 300.
It was adjusted to be ± 50 seconds to obtain a heat-sensitive recording material. In the color development test of the heat-sensitive recording material, printing was performed at a printing energy of 10 mJ / mm ² using a printing tester manufactured by Kyocera, and color evaluation was performed. The raw storage stability is 2 ° C under the conditions of 60 ° C and 30% RH.
The whiteness of the background after standing for 4 hours was measured. Table 1 shows the above results.

[0061]

[Table 1]

[0062]

As is clear from the results shown in Table 1, the heat-sensitive recording material of the present invention has excellent performance in raw preservability and coloring.

Claims (2)

[Claims] 1. A thermosensitive recording material having a thermosensitive recording layer containing an electron-donating colorless dye and an electron-accepting compound provided on a support, wherein at least one of the electron-accepting compounds is represented by the following general formula I: A heat-sensitive recording material, which is a compound. Embedded image In the formula, R ¹ , R ² and R ³ represent a hydrogen atom, an alkyl group, an aryl group, a cyano group, a nitro group, a halogen atom, an acylamino group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyl group, an alkylsulfonyl group, an aryl Represents a sulfonyl group, a sulfonamide group, an alkoxy group, an aryloxy group, a carbamoyl group, an amino group, a ureido group, a carbamoyloxy group, a sulfamoyl group, an alkylthio group, or an arylthio group. R ¹ and R ² may combine with each other to form a ring. 2. The heat-sensitive recording material according to claim 1, wherein the electron-donating colorless dye is a compound represented by the following general formula II. Embedded image In the formula, R ⁴ , R ⁵ , R ⁶ , and R ⁷ each independently represent a hydrogen atom, an alkyl group, or an aryl group. R ⁸ represents a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom. R ⁴ and R ⁵ , or R ⁶ and R ⁷ may combine with each other to form a ring.