JP2024057565A - Recording materials - Google Patents

Abstract

[Problem] To provide a recording material having excellent storage stability (water resistance, plasticizer resistance, oil resistance, and alcohol resistance) in the printed part. [Solution] A recording material containing a compound represented by the following general formula (1) TIFF2024057565000034.tif33168 (in formula (1), R1 represents a linear or branched alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 14 carbon atoms. R2 represents a hydrogen atom, or a linear or branched alkyl group having 1 to 4 carbon atoms), a thermal recording layer containing the recording material, and a thermal recording paper having the thermal recording layer. [Selected Figure] None

Description

The present invention relates to a recording material that has excellent storage stability of the color-developed recording area.

There are many known scientific color-developing systems that use energy such as heat, pressure, and light. Among them, color-developing systems consisting of a two-component color-developing system of a leuco dye, which is a dye precursor, and a color developer that develops color when it comes into contact with the leuco dye, are widely used in recording materials. For example, a thermal recording material is generally made by dispersing a leuco dye and a color developer such as a phenolic compound into fine particles, mixing the two, adding additives such as binders, sensitizers, fillers, and lubricants, and applying the resulting coating liquid to paper, film, synthetic paper, etc., and by heating, one or both of the leuco dye and the color developer melt and come into contact with each other, resulting in a chemical reaction that produces a colored record (print).

To color such thermal recording materials, a thermal printer with a built-in thermal head is used. Compared to other recording methods, thermal recording methods have the following features: (1) no noise is generated during recording; (2) no development or fixing is required; (3) maintenance is free; and (4) the machines are relatively inexpensive. For these reasons, thermal recording methods are widely used in applications such as lotteries, facsimiles, computer output, printers such as calculators, medical measurement recorders, automatic ticket vending machines, and thermal recording labels. As applications expand, thermal recording materials are used in a variety of environments, and therefore the color recording materials are required to have heat resistance, moisture resistance, water resistance, light resistance, oil resistance, alcohol resistance, plasticity resistance, etc.

Generally, color-developing compounds having phenolic hydroxyl groups have high color-developing ability, and many bisphenol-based compounds, such as those shown in Patent Documents 1 to 6, have been reported for their high color-developing density. However, the use of phenol-based compounds such as 2,2-bis(4-hydroxyphenylpropane) (bisphenol A) described in Patent Document 1, for example, is problematic due to endocrine problems, and non-phenol-based color-developing compounds that do not contain a phenol structure are in demand. As non-phenol-based color-developing compounds, diphenylurea-based, sulfonylurea-based, and amide-based color-developing compounds, such as those shown in Patent Documents 7 to 16, have been reported. However, the compounds described in these documents have a problem in that they cannot simultaneously achieve durability under hydrophilic conditions such as water resistance and alcohol resistance, and durability under hydrophobic conditions such as oil resistance and plasticizer resistance, and therefore there are certain limitations to the expansion of their uses, and there is a strong demand for the development of thermal recording materials with excellent storage stability.

U.S. Pat. No. 3,539,375 Japanese Patent Application Laid-Open No. 57-11088 Japanese Patent Application Laid-Open No. 60-208286 Japanese Patent Application Laid-Open No. 60-13852 JP 2004-9593 A Japanese Patent Publication No. 7-12749 JP 2002-532441 A International Publication No. 2014/080615 International Publication No. 2017/111032 Patent No. 2803078 Patent No. 7027199 International Publication No. 2021/041600 International Publication No. 2016/052592 International Publication No. 2000/014058 Patent No. 2666655 International Publication No. 2019/044462

The present invention aims to provide a recording material that has excellent storage stability in the printed area.

As a result of intensive research into achieving the above object, the inventors discovered that a recording material containing a compound having a specific structure provides a heat-sensitive recording layer that is excellent in water resistance, plasticizer resistance, oil resistance, and alcohol resistance, and that the compound also has an excellent effect of improving the storage stability of the color developer, leading to the completion of the present invention. Note that in this application, "(Numerical value 1) to (Numerical value 2)" indicates that the upper and lower limits are included.

That is, the present invention is
[1] The following general formula (1)

(In the formula (1), R ₁ represents a linear or branched alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 14 carbon atoms; R ₂ represents a hydrogen atom, or a linear or branched alkyl group having 1 to 4 carbon atoms),
[2]
The following general formula (2)

(in general formula (2), R ₃ represents a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, a linear or branched alkoxy group having 1 to 4 carbon atoms, a cyano group, or a halogen atom, and n represents an integer of 1 to 5),
[3] A compound represented by the following formula (18):

[4] A color developer represented by the general formula (1) according to the above [1].
[5] A color developer represented by the general formula (2) according to [2] above.
[6] A color developer represented by formula (18) according to the above [3].
[7] A recording material containing the compound according to any one of [1] to [3] above.
[8] The recording material according to any one of [1] to [3] above, further comprising a color developer.
[9] The color developer according to [8] above is selected from the group consisting of N-(2-(3-phenylureido)phenyl)benzenesulfonamide (formula (3) below), 3-(3-phenylureido)phenyl=4-methylbenzenesulfonate (formula (4) below), 3-(3-tosylureido)phenyl=4-methylbenzenesulfonate (formula (5) below), 1,3-diphenylurea (formula (6) below), 3-(3-phenylureido)benzenesulfonamide (formula (7) below), N ¹ ,N ³ a recording material which is at least one of compounds represented by the following formula (8) such as 3,3'-di-m-tolyl-5-(N-(m-tolyl)sulfamoyl)isophthalamide (formula (8) below), 3,3'-diallyl-4,4'-dihydroxydiphenylsulfone (formula (9) below), 4,4'-dihydroxydiphenylsulfone (formula (10) below), 4-hydroxy-4'-isopropoxydiphenylsulfone (formula (11) below), 4-allyloxy-4'-hydroxydiphenylsulfone (formula (12) below), 2,4'-dihydroxydiphenylsulfone (formula (13) below), 2,2-bis(4-hydroxyphenylpropane) (formula (14) below), N-(2-(3-phenylureido)phenyl)acetamide (formula (15) below), 4,4'-bis(3-tosylureido)diphenylmethane (formula (16) below), and formula (17) below;

[10] A thermosensitive recording layer comprising the recording material according to any one of [7] to [9] above.
[7] A thermal recording paper having the thermal recording layer according to [10] above.
[8] An ink containing the recording material according to any one of [7] to [9] above.
Regarding.

The compound represented by general formula (1) provides a thermal recording material with excellent storage stability of the printed area.

The present invention relates to a compound represented by the following general formula (1). The compound has excellent effects both as a color developer and as a storage stability improver that improves the storage stability of the printed portion.

In general formula (1), R ₁ represents a linear or branched alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 14 carbon atoms. Specific examples of the alkyl group represented by R ₁ in general formula (1) include linear methyl, ethyl, n-propyl, and n-butyl groups, preferably methyl or ethyl groups, and branched isopropyl, isobutyl, sec-butyl, and t-butyl groups, preferably isopropyl groups.

The aryl group represented by R ₁ in general formula (1) is not particularly limited as long as it has 6 to 12 carbon atoms, but is preferably an aryl group having 6 to 10 carbon atoms, and specific examples thereof include a phenyl group and a naphthyl group, and is preferably a phenyl group.

The aryl group represented by R ₁ in the general formula (1) may have a substituent. The substituent of the aryl group represented by R ₁ in the formula (1) may be a linear or branched alkyl group having 1 to 4 carbon atoms, and a methyl group is preferred. The number of the substituents of the aryl group represented by R ₁ in the general formula (1) is not particularly limited as long as it is equal to or less than the number of the sites that can be substituted (5 in the case of a phenyl group, and 7 in the case of a naphthyl group). The substitution position of the substituent of the aryl group represented by R ₁ in the general formula (1) is also not particularly limited. In this specification, the term "substituted aryl group" means an aryl group in which a hydrogen atom of the aryl group is substituted with an alkyl group or the like, and the term "unsubstituted aryl group" means an aryl group in which a hydrogen atom of the aryl group is not substituted with a substituent or the like.

In general formula (1), R ₂ represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. Specific examples and preferred examples of the linear or branched alkyl group having 1 to 4 carbon atoms represented by R ₂ in general formula (1) include the same specific examples and preferred examples of the alkyl group represented by R ₁ in general formula (1). The substitution position of R ₂ in general formula (1) is not particularly limited, but is preferably either of the carbon atoms adjacent to the carbon atom bonded to the nitrogen atom on the benzene ring specified in the center of general formula (1).

The compound represented by the general formula (1) is preferably a combination of the above-mentioned preferred embodiments of R ₁ and R _2. That is, the compound represented by the general formula (1) is preferably a compound represented by the following general formula (2).

In general formula (2), _R3 represents a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, a linear or branched alkoxy group having 1 to 4 carbon atoms, a cyano group, or a halogen atom; and n represents an integer of 1 to 5.

Specific examples and preferred examples of the linear or branched alkyl group having 1 to 4 carbon atoms represented by R ₃ in general formula (2) include the same specific examples and preferred examples of the alkyl group represented by R ₁ in general formula (1).

Specific examples of the alkoxy group represented by _R3 in general formula (2) include linear methoxy, ethoxy, n-propoxy and n-butoxy groups, preferably methoxy or ethoxy groups, and branched isopropoxy, isobutoxy, sec-butoxy and t-butoxy groups, preferably t-butoxy groups.

In general formula (2), n is an integer from 1 to 5, preferably from 1 to 3, and more preferably 1.

In the general formula (2), when R ₁ is a phenyl group and n=1, the substitution position is preferably the 2-, 3- or 4-position of the phenyl group, more preferably the 2- or 4-position, and even more preferably the 4-position.

In the present invention, the most preferred compound of general formula (1) is the compound represented by the following formula (18):

Other specific examples of compounds represented by general formula (1) are listed below, but are not limited to these.

The compound represented by the general formula (1) can be produced by combining known synthesis methods. An example of a synthesis flow is described below, but the method for producing the compound represented by the general formula (1) is not limited to this synthesis flow. Note that _R1 and _R2 in the following synthesis flow are the same as _R1 and _R2 in the general formula (1).

First, in "STEP 1," 2-nitroaniline represented by formula [1-1] is reacted with a sulfonic acid chloride represented by formula [1-2] in the presence or absence of a base to obtain a compound represented by formula [1-3].

In the next step, STEP 2, the compound represented by formula [1-3] obtained in STEP 1 is reduced to obtain a compound represented by formula [1-4].

Finally, in "STEP 3", the compound represented by formula [1-4] obtained in STEP 2 is reacted with a diisocyanate compound represented by formula [2-1] in the presence or absence of a base to obtain a compound represented by general formula (1).

The base optionally used in STEPs 1 and 3 includes, for example, inorganic bases such as sodium hydroxide, potassium hydroxide, sodium hydrogen carbonate, sodium carbonate, potassium hydrogen carbonate, potassium carbonate, and cesium carbonate; and organic bases such as triethylamine, diisopropylethylamine, pyridine, and dimethylaminopyridine. The amount of these bases used is preferably 1 to 3 times the molar amount of the compound represented by formula [1-1].

The reactions in STEPs 1 to 3 are preferably carried out in a solution state in which the raw materials and intermediates are dissolved in a solvent. The solvent that can be used in the reaction is not particularly limited as long as it does not affect the reaction, but examples of the solvent include amide compounds such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; halogenated hydrocarbon compounds such as methylene chloride and chloroform; aromatic hydrocarbon compounds such as benzene, toluene, and xylene; ether compounds such as dioxane, tetrahydrofuran, anisole, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and diethylene glycol diethyl ether; nitrile compounds such as acetonitrile; ketone compounds such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; ester compounds such as ethyl acetate and butyl acetate; sulfone compounds such as sulfolane; sulfoxide compounds such as dimethyl sulfoxide; and alcohol compounds such as methanol, ethanol, and isopropyl alcohol. These may be used alone or in combination.

The reducing agent used in STEP 2 is not particularly limited as long as it does not affect the sulfonyl group, but examples include hydrogen, iron powder, and hydrazine. When hydrogen or hydrazine is used, a catalyst such as palladium/carbon or iron chloride/carbon may also be used.

The reaction temperature for SETP 1 to 3 is usually -78 to 110°C, preferably 0 to 100°C, and the reaction time is usually 10 minutes to 24 hours.

In the present invention, other color developers may be used in combination. These other color developers may be any color developers generally used in pressure-sensitive recording paper or heat-sensitive recording paper, and examples of such color developers include α-naphthol, β-naphthol, p-octylphenol, 4-t-octylphenol, p-t-butylphenol, p-phenylphenol, 1,1-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)propane (also known as bisphenol A or BPA, formula (14) above), 2,2-bis(4-hydroxyphenyl)butane, 1,1 ... 4,4'-diphenyl)cyclohexane, 4,4'-thiobisphenol, 4,4'-cyclo-hexylidene diphenol, 2,2'-bis(2,5-dibromo-4-hydroxyphenyl)propane, 4,4'-isopropylidenebis(2-t-butylphenol), 2,2'-methylenebis(4-chlorophenol), 4,4'-dihydroxydiphenylsulfone (formula (10) above), 4-hydroxy-4'-methoxydiphenylsulfone, 2,4'-dihydroxydiphenylsulfone (formula (13) above) ), 4-hydroxy-4'-isopropoxydiphenyl sulfone (the above formula (11)), 4-allyloxy-4'-hydroxydiphenyl sulfone (the above formula (12)), 3,3'-diallyl-4,4'-dihydroxydiphenyl sulfone (the above formula (9)), 4-hydroxy-4'-ethoxydiphenyl sulfone, 4-hydroxy-4'-butoxydiphenyl sulfone, 4-hydroxy-4'-benzyloxydiphenyl sulfone, bis(4-hydroxyphenyl)methyl acetate, bis(4-hydroxy phenolic compounds such as 2,4-dihydroxy-2'-methoxybenzanilide, benzyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, dibenzyl 4-hydroxyphthalate, dimethyl 4-hydroxyphthalate, ethyl 5-hydroxyisophthalate, 3,5-di-t-butylsalicylic acid, 3,5-di-α-methylbenzylsalicylic acid, aromatic carboxylic acid derivatives such as aromatic carboxylic acids or polyvalent metal salts thereof, N Examples of the acid amide derivatives include ¹ ,N ³ -di-m-tolyl-5-(N-(m-tolyl)sulfamoyl)isophthalamide (the above formula (8)), and sulfonylurea derivatives include N-(2-(3-phenylureido)phenyl)benzenesulfonamide (the above formula (3)), 3-(3-phenylureido)phenyl=4-methylbenzenesulfonate (the above formula (4)), 1,3-diphenylurea (the above formula (6)), 3-(3-phenylureido)benzenesulfonamide (the above formula (7)), N-(2-(3-phenylureido)phenyl)acetamide (the above formula (15)), 3-(3-tosylureido)phenyl=4-methylbenzenesulfonate (the above formula (5)), and 4,4′-bis(3-tosylureido)diphenylmethane (the above formula (16)).

Other examples of color developers include diphenyl urea derivatives such as the compound represented by formula (17) (such as color developer compound UU manufactured by Chemipro Chemical Co., Ltd.), which are also used as storage stability improvers.

One embodiment of the recording material of the present invention contains a compound represented by general formula (1) and a color-forming compound, and optionally contains other color developers, sensitizers, binders, fillers, and other additives.

The content of each component in the recording material of the present invention is, in terms of mass ratio to the solid content in the recording material, usually 1 to 70 mass % of the compound represented by the above general formula (1), preferably 5 to 50 mass %; usually 1 to 50 mass % of the color-developing compound, preferably 5 to 30 mass %; usually 1 to 80 mass % of the sensitizer, usually 1 to 90 mass % of the binder, usually 30 mass % or less of the storage improver, usually 80 mass % or less of the filler; and usually 30 mass % or less of other additives (lubricants, surfactants, defoamers, ultraviolet absorbers, etc.).

In addition, in the recording material of the present invention, the compound represented by general formula (1) is usually used in an amount of 0.5 to 20 parts by mass, and preferably 1 to 5 parts by mass, per 1 part by mass of the color-forming compound.

As described above, the compound represented by formula (1) has the effect of improving the storage stability of the printed portion when used in combination with other color developers, so in other embodiments, the recording material of the present invention also contains other commonly used color developers.

When the compound represented by formula (1) is used as a storage stability improver, the content of each component in the recording material of the present invention is, in terms of mass ratio relative to the solid content in the recording material, usually 1 to 90 mass % of the compound represented by formula (1), preferably 5 to 50 mass %; usually 1 to 70 mass % of the color developer, preferably 5 to 50 mass %; usually 1 to 50 mass % of the color-forming compound, preferably 5 to 30 mass %; usually 1 to 80 mass % of the sensitizer, usually 1 to 90 mass % of the binder, usually 80 mass % or less of the filler; and usually 30 mass % or less of each of the other additives (lubricant, surfactant, defoamer, UV absorber, etc.).

When the compound represented by formula (1) is used as a storage stability improver, the mass ratio of the compound represented by formula (1) to other color developers in the recording material of the present invention is usually formula (1):other color developers = 95:5 to 5:95, and preferably 3:1 to 1:9. Depending on the combination with other color developers, 1:1 to 1:9 is also preferable.

In addition, in the recording material of the present invention, the other color developer is usually used in an amount of 0.5 to 20 parts by weight, preferably 1 to 5 parts by weight, per part by weight of the color-forming compound. In addition, the storage stability improver having a compound represented by general formula (1) as a main component is usually used in an amount of 0.1 to 20 parts by weight, preferably 0.1 to 10 parts by weight, per part by weight of the other color developer.

The color-forming compound preferably used in the recording material of the present invention is not particularly limited as long as it is generally used in pressure-sensitive recording paper or heat-sensitive recording paper.
Examples of the color-developing compound include fluoran-based compounds, triarylmethane-based compounds, spiro-based compounds, diphenylmethane-based compounds, thiazine-based compounds, lactam-based compounds and fluorene-based compounds, with fluoran-based compounds being preferred.

Specific examples of fluoran compounds include 3-diethylamino-6-methyl-7-anilinofluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3-(N-methyl-N-cyclohexylamino)-6-methyl-7-anilinofluoran, 3-(N-ethyl-N-isopentylamino)-6-methyl-7-anilinofluoran, 3-(N-ethyl-N-isobutylamino)-6-methyl-7-anilinofluoran, 3-[N-ethyl-N-(3-ethoxypropyl)amino]-6-methyl-7 -anilinofluoran, 3-(N-ethyl-N-hexylamino)-6-methyl-7-anilinofluoran, 3-dipentylamino-6-methyl-7-anilinofluoran, 3-(N-methyl-N-propylamino)-6-methyl-7-anilinofluoran, 3-(N-ethyl-N-tetrahydrofurylamino)-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-(p-chloroanilino)fluoran, 3-diethylamino-6-methyl-7-(p-fluoroanilino)fluoran, 3-[N-ethyl-N-(p-tolyl)amino]-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-(p-toluidino)fluoran, 3-diethylamino-7-(o-chloroanilino)fluoran, 3-dibutylamino-7-(o-chloroanilino)fluoran, 3-diethylamino-7-(o-fluoroanilino)fluoran, 3-dibutylamino-7-(o-fluoroanilino)fluoran, 3-diethylamino-7-(3,4-dichloroanilino)fluoran, 3-pyrrolidino No-6-methyl-7-anilinofluoran, 3-diethylamino-6-chloro-7-ethoxyethylaminofluoran, 3-diethylamino-6-chloro-7-anilinofluoran, 3-diethylamino-7-chlorofluoran, 3-diethylamino-7-methylfluoran, 3-diethylamino-7-octylfluoran, and 3-[N-ethyl-N-(p-tolyl)amino]-6-methyl-7-phenethylfluoran, etc. are included, and 3-dibutylamino-6-methyl-7-anilinofluoran is preferred.

Specific examples of triarylmethane compounds include 3,3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (also known as crystal violet lactone or CVL), 3,3-bis(p-dimethylaminophenyl)phthalide, 3-(p-dimethylaminophenyl)-3-(1,2-dimethylaminoindol-3-yl)phthalide, 3-(p-dimethylaminophenyl)-3-(2-methylindol-3-yl)phthalide, and 3-(p-dimethylaminophenyl)-3-(2-phenylindol-3-yl)phthalide. Examples include 3,3-bis(1,2-dimethylindol-3-yl)phthalide, 3,3-bis(1,2-dimethylindol-3-yl)-5-dimethylaminophthalide, 3,3-bis(1,2-dimethylindol-3-yl)-6-dimethylaminophthalide, 3,3-bis(9-ethylcarbazol-3-yl)-5-dimethylaminophthalide, 3,3-(2-phenylindol-3-yl)-5-dimethylaminophthalide, and 3-p-dimethylaminophenyl-3-(1-methylpyrrol-2-yl)-6-dimethylaminophthalide.

Specific examples of spiro compounds include 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3,3'-dichlorospirodinaphthopyran, 3-benzylspirodinaphthopyran, 3-propylspirobenzopyran, 3-methylnaphtho-(3-methoxybenzo)spiropyran, 1,3,3-trimethyl-6-nitro-8'-methoxyspiro(indoline-2,2'-benzopyran), and the like.
Specific examples of diphenylmethane compounds include N-halophenyl-leucoauramine, 4,4-bis-dimethylaminophenyl benzhydryl benzyl ether, and N-2,4,5-trichlorophenyl leucoauramine.
Specific examples of thiazine compounds include benzoyl leuco methylene blue, p-nitrobenzoyl leuco methylene blue, and the like.

Specific examples of lactam compounds include rhodamine B anilinolactam, rhodamine B p-chloroanilinolactam, and the like.
Specific examples of fluorene-based compounds include 3,6-bis(dimethylamino)fluorene spiro(9,3')-6'-dimethylaminophthalide, 3,6-bis(dimethylamino)fluorene spiro(9,3')-6'-pyrrolidinophthalide, and 3-dimethylamino-6-diethylaminofluorene spiro(9,3')-6'-pyrrolidinophthalide.
These color-forming compounds may be used alone or in combination.

Sensitizers (heat-fusible compounds) preferably used in the recording material of the present invention include waxes such as animal and vegetable waxes and synthetic waxes, higher fatty acids, higher fatty acid amides, higher fatty acid anilides, naphthalene derivatives, aromatic ethers, aromatic carboxylic acid derivatives, aromatic sulfonic acid ester derivatives, carbonic acid or oxalic acid diester derivatives, biphenyl derivatives, terphenyl derivatives, sulfone derivatives, aromatic ketone derivatives, aromatic hydrocarbon compounds, etc.

Examples of waxes include wood wax, carnauba wax, shellac, paraffin, montan wax, oxidized paraffin, polyethylene wax, and oxidized polyethylene; examples of higher fatty acids include stearic acid and behenic acid; examples of higher fatty acid amides include stearic acid amide, oleic acid amide, N-methylstearic acid amide, erucic acid amide, methylol behenic acid amide, methylene bisstearic acid amide, and ethylene bisstearic acid amide; examples of higher fatty acid anilides include stearic acid anilide and linoleic acid anilide; examples of naphthalene derivatives include Examples of aromatic ethers include 1,2-diphenoxyethane, 1,4-diphenoxybutane, 1,2-bis(3-methylphenoxy)ethane, 1,2-bis(4-methoxyphenoxy)ethane, 1,2-bis(3,4-dimethylphenyl)ethane, 1-phenoxy-2-(4-chlorophenoxy)ethane, 1-phenoxy-2-(4-methoxyphenoxy)ethane, 1,2-diphenoxymethylbenzene, and diphenyl glycols, etc.; aromatic carboxylic acid derivatives include, for example, p-hydroxybenzoic acid benzyl ester, p-benzyloxybenzoic acid benzyl ester, and terephthalic acid dibenzyl ester; aromatic sulfonic acid ester derivatives include, for example, p-toluenesulfonic acid phenyl ester, phenylmesitylenesulfonate, 4-methylphenylmesitylenesulfonate, and 4-tolylmesitylenesulfonate; carbonic acid or oxalic acid diester derivatives include, for example, diphenyl carbonate, oxalic acid dibenzyl ester, oxalic acid di(4-chlorobenzyl) ester, and oxalic acid di( 4-methylbenzyl) esters; biphenyl derivatives include, for example, p-benzylbiphenyl and p-allyloxybiphenyl; terphenyl derivatives include, for example, m-terphenyl; sulfone derivatives include, for example, p-toluenesulfonamide, benzenesulfonanilide, p-toluenesulfonanilide, 4,4'-diallyloxydiphenyl sulfone, and diphenyl sulfone; aromatic ketone derivatives include, for example, 4,4'-dimethylbenzophenone and dibenzoylmethane; and aromatic hydrocarbon compounds include, for example, p-acetotoluidine.

Specific examples of binders that are preferably used in the heat-sensitive material of the present invention include water-soluble or (meth)soluble binders such as methyl cellulose, methoxy cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose, cellulose, polyvinyl alcohol (PVA), carboxyl group-modified polyvinyl alcohol, sulfonic acid group-modified polyvinyl alcohol, silyl group-modified polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, polyacrylic acid, starch and its derivatives, casein, gelatin, water-soluble isoprene rubber, alkali salts of styrene/maleic anhydride copolymers, and alkali salts of iso(or diiso)butylene/maleic anhydride copolymers. ) acrylic acid ester copolymers, styrene/(meth)acrylic acid ester copolymers, polyurethane, polyester polyurethane, polyether polyurethane, polyvinyl acetate, ethylene/vinyl acetate copolymer, polyvinyl chloride, vinyl chloride/vinyl acetate copolymer, polyvinylidene chloride, polystyrene, styrene/butadiene (SB) copolymer, carboxylated styrene/butadiene (SB) copolymer, styrene/butadiene/acrylic acid copolymer, acrylonitrile/butadiene (NB) copolymer, carboxylated acrylonitrile/butadiene (NB) copolymer, hydrophobic polymer emulsions such as colloidal silica and (meth)acrylic resin composite particles, etc.

Specific examples of storage stability improvers that can be used in combination with the present invention include 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 2,2'-ethylidenebis(4,6-di-tert-butylphenol), 4,4'-thiobis(2-methyl-6-tert-butylphenol), 4,4'-butylidenebis(6-tert-butyl-m-cresol), 1-[α-methyl-α-(4'-hydroxyphenyl) 1,1,3-tris(2-methyl-4-hydroxy-5-cyclohexylphenyl)butane, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, tris(2,6-dimethyl-4-tert-butyl-3-hydroxybenzyl)isocyanurate, 4,4'-thiobis(3-methylphenol), 4,4'-dihydroxy-3,3',5,5'-tetrahydroxy-3,3' ... hindered phenol compounds such as tetrabromodiphenyl sulfone, 4,4'-dihydroxy-3,3',5,5'-tetramethyldiphenyl sulfone, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 1,4-diglycidyloxybenzene, 4,4'-diglycidyloxydiphenyl sulfone, 4-benzyloxy Examples of the epoxy compounds include 4'-(2-methylglycidyloxy)diphenylsulfone, diglycidyl terephthalate, cresol novolac epoxy resins, phenol novolac epoxy resins, and bisphenol A epoxy resins; N,N'-di-2-naphthyl-p-phenylenediamine; sodium or polyvalent metal salts of 2,2'-methylenebis(4,6-di-tert-butylphenyl)phosphate; and bis(4-ethyleneiminocarbonylaminophenyl)methane. For example, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 2,2'-ethylidenebis(4,6-di-tert-butylphenol), 4,4'-thiobis(2-methyl-6-tert-butylphenol), 4,4'-butylidenebis(6-tert-butyl-m-cresol), 1-[α-methyl-α-(4'-hydroxyphenyl)ethyl]-4-[α',α'-bis(4'-hydroxyphenyl)ethyl]- diphenyl)ethyl]benzene, 1,1,3-tris(2-methyl-4-hydroxy-5-cyclohexylphenyl)butane, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, tris(2,6-dimethyl-4-tert-butyl-3-hydroxybenzyl)isocyanurate, 4,4'-thiobis(3-methylphenol), 4,4'-dihydroxy-3,3',5,5'-tetrabromodiphenylsulfone, 4,4'-dihydroxy-3,3', Hindered phenol compounds such as 5,5'-tetramethyldiphenyl sulfone, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 1,4-diglycidyloxybenzene, 4,4'-diglycidyloxydiphenyl sulfone, 4-benzyloxy-4'-(2-methylglycidyloxy)diphenyl sulfone, diterephthalic acid Examples of such epoxy compounds include glycidyl, cresol novolac epoxy resins, phenol novolac epoxy resins, and bisphenol A epoxy resins; N,N'-di-2-naphthyl-p-phenylenediamine; sodium or polyvalent metal salts of 2,2'-methylenebis(4,6-di-tert-butylphenyl)phosphate; bis(4-ethyleneiminocarbonylaminophenyl)methane; and diphenylsulfone-bridged compounds represented by the following formula (19) or mixtures thereof. In formula (19), a is an integer from 0 to 6.

Specific examples of fillers that can be used in combination with the recording material of the present invention include calcium carbonate, magnesium carbonate, magnesium oxide, silica, white carbon, talc, clay, alumina, magnesium hydroxide, aluminum hydroxide, aluminum oxide, barium sulfate, polystyrene resin, urea-formalin resin, etc.

Other additives that can be used in combination with the recording material of the present invention include, for example, higher fatty acid metal salts such as zinc stearate and calcium stearate, which are used for purposes such as preventing thermal head wear and sticking, ultraviolet absorbers such as phenol derivatives, benzophenone compounds, and benzotriazole compounds, which are used to impart antioxidant and anti-aging effects, and various surfactants and defoamers.

Next, the method for preparing the recording material and thermal recording paper of the present invention will be described. The compound represented by general formula (1) and/or the color developer, which are essential components of the recording material of the present invention, and the color-forming compound are pulverized and dispersed in a dispersing machine such as a ball mill, attritor, or sand mill together with a binder or, if necessary, other additives to prepare respective dispersions (usually, when pulverization or dispersion is performed in a wet manner, water is used as a medium), and the dispersions are mixed together to prepare a coating liquid for the recording material, which is then coated on a support such as paper (plain paper, wood-free paper, coated paper, etc. can be used), a plastic sheet, or synthetic paper with a bar coater, blade coater, etc. so that the dry weight is usually 1 to 20 g/ ^m2 , and then dried to obtain a thermal recording paper having a thermal recording layer containing the recording material of the present invention.
In this specification, the category of "thermosensitive recording paper" includes a support other than paper on which a thermosensitive recording layer is provided.

If necessary, an intermediate layer may be provided between the heat-sensitive recording layer and the support, or an overcoat layer (protective layer) may be provided on the heat-sensitive recording layer. The intermediate layer or overcoat layer (protective layer) may be formed, for example, in the same manner as in the preparation of the coating solution for the recording material described above, by pulverizing and dispersing the components required for the intermediate layer or overcoat layer together with a binder or other additives used as necessary to prepare a coating solution, and then coating the solution so that the dry weight is usually about 0.1 to 10 g/ ^m2 , and drying the solution.

The coating liquid (dispersion) of the recording material of the present invention described above can also be incorporated into general writing instrument inks or inkjet inks. For example, writing instrument inks can be prepared by mixing a dispersion of the recording material with a water-based ink containing water as a solvent, a water-soluble organic solvent, a thickener, a lubricant, an anti-rust agent, a preservative, or an antibacterial agent, etc., appropriately blended depending on the application, or an oil-based ink containing a main solvent such as polypropylene glycol, polybutylene glycol, or polyoxypropylene diglyceryl ether, a resin, a lubricant, an anti-rust agent, a preservative, or an antibacterial agent, etc., appropriately blended depending on the application.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the examples, "parts" means parts by mass, and "%" means % by mass.

Example 1 (Compound No. 30 in Table 1 (hereinafter referred to as "No. 30"))
(Step 1) Synthesis of intermediate compound 1 represented by the following formula (100-4) 75 parts of 2-nitroaniline (Tokyo Chemical Industry) represented by the following formula (100-1), 129 parts of p-toluenesulfonyl chloride represented by the following formula (100-2), and 110 parts of pyridine (Junsei Chemical) were added to 420 parts of methyl isobutyl ketone, and the mixture was stirred at 100°C until p-toluenesulfonyl chloride was completely reacted. The reaction solution was cooled to room temperature, and then stirred for 1 hour to precipitate crystals. The precipitate was removed by liquid filtration, and the obtained filtrate was concentrated, and methanol was added to precipitate crystals. The precipitated crystals were collected by filtration, washed with methanol, and dried to obtain 80 parts of a yellow solid of intermediate compound 1 (4-methyl-N-(2-nitrophenyl)benzenesulfonamide) represented by the following formula (100-4).

(Step 2) Synthesis of intermediate compound 2 represented by the following formula (101-3) 50.0 parts of intermediate compound 1 obtained in step 1, 7.3 parts of activated carbon, and 7.6 parts of iron (III) chloride hexahydrate were added to 500.0 parts of methanol, and the mixture was heated to reflux temperature. Then, 45.0 parts of hydrazine monohydrate (Tokyo Chemical Industry) represented by the following formula (101-1) was added dropwise, and the mixture was stirred under reflux for 3 hours. The filtrate obtained by removing the activated carbon by liquid filtration was concentrated to precipitate crystals. The precipitated crystals were filtered, washed with a 30% aqueous methanol solution, and dried to obtain 32.0 parts of a pale yellow solid of intermediate compound 2 (N-(2-aminophenyl)-4-methylbenzenesulfonamide) represented by the following formula (101-3).

(Step 3) Synthesis of No. 30 (Formula (102-2)) 8.0 parts of intermediate compound 2 obtained in step 2 was added to 80.0 parts of ethyl acetate and stirred at room temperature. Then, 2.3 parts of 2,4-tolylene diisocyanate (Tokyo Chemical Industry Co., Ltd.) represented by the following formula (102-1) was added dropwise, and the mixture was stirred at room temperature for 1 hour to precipitate crystals. The precipitated crystals were filtered off, washed with ethyl acetate, and dried to obtain 8.0 parts of a white solid of compound (No. 30) represented by the following formula (102-2).

Example 2 and Comparative Examples 1 to 5 (Preparation of Coating Solution for Recording Material and Preparation of Thermal Recording Paper Having a Thermal Recording Layer Containing the Recording Material)
(Preparation of Liquid [A] (Developer Dispersion Liquid))
Using a multi-beads shocker (model: PV1001(S)) manufactured by Yasui Kikai Co., Ltd.,
No. 30 obtained in Example 1, the formulas (3) to (5), (10) and N,N'-di-[3-(p-toluenesulfonyloxy)phenyl]urea (the following formula (20)) described in Patent Documents 2, 7 to 9, and 16, and other components were mixed in the compositions described in Table 7, and ground and dispersed for 1 hour to prepare solutions [A] (A-1 to A-6), respectively.

The “other components” used in solution [A] are as follows:
PVA aqueous solution: 20% aqueous solution of Gohsenex L-3266 (manufactured by Mitsubishi Chemical Corporation) SF104: Surfynol 104PG-50 (50% propylene glycol solution of Surfynol 104 manufactured by Nissin Chemical Industry Co., Ltd.)

(Preparation of solution [B])
A mixture of the following composition was pulverized and dispersed using a sand grinder so that the median particle size measured with a laser diffraction/scattering type particle size distribution measuring device LA-950 (manufactured by Horiba, Ltd.) was 1 μm, thereby preparing a dispersion liquid [B] of a color-forming compound.

PSD-290 35 parts PVA aqueous solution 40 parts Water 25 parts

The components used in solution [B] are as follows:
PSD-290: 2-anilino-6-dibutylamino-3-methylfluoran (manufactured by Nippon Soda Co., Ltd.)
PVA aqueous solution: 15% aqueous solution of Gohsenex L-3266 (manufactured by Mitsubishi Chemical Corporation)

(Preparation of Coating Solution for Recording Material)
The above obtained liquid [A], liquid [B] and other components were mixed in the composition shown in Table 8 to prepare a coating liquid for the recording material.

Details of the components other than the liquid [A] and the liquid [B] used in the coating liquid for the recording material are as follows.

Calcium carbonate dispersion: 67% aqueous dispersion of calcium carbonate (YCC-FD, manufactured by Yabashi Kogyo Co., Ltd.) PVA dispersion: 15% aqueous dispersion of polyvinyl alcohol (PVA-110, manufactured by Kuraray Co., Ltd.) St-Zn dispersion: 27% aqueous dispersion of zinc stearate (manufactured by GOO Chemical Co., Ltd.)

Example 3 and Comparative Examples 6 to 10 (Preparation of Thermal Recording Paper)
The coating solutions of the recording materials obtained in Example 2 and Comparative Examples 1 to 5 were each coated on a sheet of wood-free paper having a basis weight of 50 g/ ^m2 so that the dry weight was 5 g/ ^m2 , and then dried to prepare thermal recording papers of the present invention and for comparison. The water resistance, plasticizer resistance, oil resistance, and alcohol resistance were evaluated as follows.

(Water resistance evaluation)
Using a thermal printer (TH-M2/PP) manufactured by Okura Engineering Co., Ltd., printing was performed on each of the thermal recording papers obtained in Example 3 and Comparative Examples 6 to 10 with a pulse width of 1.4 msec, and the printed matter was immersed in water and left for 24 hours, then removed and dried. Using a colorimeter manufactured by X-Rite, product name "eXact", the reflection density of the colored part of the thermal recording paper before and after immersion was measured under the conditions of Illuminant C as the light source, Status A as the density standard, and a viewing angle of 2 degrees.
Reflection density after immersion/Reflection density before immersion×100
The remaining rate (%) of the colored portion was calculated using the formula above, and the water resistance was evaluated according to the following evaluation criteria. A higher remaining rate means better water resistance. The results are shown in Table 9.
Evaluation criteria: A: Residual rate of 90% or more; B: Residual rate of 85% or more but less than 90%; C: Residual rate of 80% or more but less than 85%; D: Residual rate of less than 80%

(Plasticizer resistance evaluation)
Both the recording layer side and the back side of each thermal recording paper printed in the same manner as in the "Water Resistance Evaluation" were covered with a double layer of PVC wrap (product name: Denka Wrap Fresh, manufactured by Denka Polymer Co., Ltd.) and left at 40°C for 2.5 hours, after which the PVC wrap was removed. Using the same method and formula as in the "Water Resistance Evaluation of Thermal Recording Paper" above, the remaining rate (%) of the colored portion before and after leaving at 40°C for 2.5 hours was calculated, and the plasticizer resistance was evaluated according to the following evaluation criteria. A higher remaining rate means better plasticizer resistance. The results are shown in Table 9.
Evaluation criteria: A: Residual rate of 85% or more; B: Residual rate of 75% or more but less than 85%; C: Residual rate of 50% or more but less than 75%; D: Residual rate of less than 50%.

(Oil resistance evaluation)
Cottonseed oil (Tokyo Chemical Industry Co., Ltd.) was applied to the printed area of each thermal recording paper printed in the same manner as in the "Water Resistance Evaluation" above, and the paper was left at room temperature for 1.5 hours, after which the cottonseed oil was wiped off. Using the same method and formula as in the "Water Resistance Evaluation of Thermal Recording Paper" above, the residual rate (%) of the colored area before and after leaving the paper at room temperature for 1.5 hours was calculated, and the oil resistance was evaluated according to the following evaluation criteria. A higher residual rate means better oil resistance. The results are shown in Table 9.
Evaluation criteria: A: Residual rate of 95% or more; B: Residual rate of 85% or more but less than 95%; C: Residual rate of 65% or more but less than 85%; D: Residual rate of less than 65%.

(Alcohol resistance evaluation)
Each thermal recording paper printed in the same manner as in the "Water Resistance Evaluation" was immersed in a 20% ethanol aqueous solution, left at room temperature for 2 hours, and then removed and dried. Using the same method and formula as in the "Water Resistance Evaluation of Thermal Recording Paper" above, the remaining percentage (%) of the colored portion before and after leaving at room temperature for 2 hours was calculated, and the alcohol resistance was evaluated according to the following evaluation criteria. A higher remaining percentage means better alcohol resistance. The results are shown in Table 9.
Evaluation criteria: A: Residual rate 100% or more; B: Residual rate 80% or more but less than 100%; C: Residual rate 60% or more but less than 80%; D: Residual rate less than 60%.

The results of the water resistance test, plasticizer resistance test, oil resistance test and alcohol resistance test clearly show that the thermal recording paper of the example using the compound of the present invention is superior in all the categories of water resistance, plasticizer resistance, oil resistance and alcohol resistance to the thermal recording paper of the comparative example using the compounds described in Patent Documents 2, 7 to 9 and 16, and there is no bias.

Examples 4 to 51 and Comparative Examples 11 to 25 (Preparation of Coating Liquid for Recording Material)
(Preparation of Liquid [A] (Developer Dispersion Liquid))
Using a Multi-Beads Shocker (model: PV1001(S)) manufactured by Yasui Kikai Co., Ltd., the compounds represented by the above formulas (3) to (17) described in Patent Documents 1 to 15 and other components were mixed in the compositions shown in Table 10, and ground and dispersed for 1 hour to prepare each of the [A] solutions ([A-(3)] to [A-(17)]). The other components other than [A] solution were the same as those in [A] solutions in Example 2 and Comparative Examples 1 to 5.

(Preparation of Liquid [B] (Dispersion Liquid of Color-Developing Compound))
Liquid [B] was prepared using the same composition and preparation method as liquid [B] in Example 2 and Comparative Examples 1 to 5.

(Preparation of Liquid [C] (Dispersion of Storage Quality Improver))
Using a multi-beads shocker (model: PV1001(S)) manufactured by Yasui Kikai Co., Ltd., No. 30 obtained in Synthesis Example 1 and other components were mixed in the composition shown in Table 11, and ground and dispersed for 1 hour to prepare solution [C]. The other components used in solution [C] were the same as those in solution [A].

The [A] liquid, [B] liquid, and [C] liquid obtained above, and other components were mixed in the compositions shown in Table 12 to prepare coating liquids for recording materials (Examples 4 to 51 and Comparative Examples 11 to 25). The compositions and types of [A] liquid used in the examples are shown in Table 13, and the compositions and types of [A] liquid used in the comparative examples are shown in Table 14. The other components other than [A] liquid, [B] liquid, and [C] liquid are the same as those in the coating liquids for recording materials in Example 2 and Comparative Examples 1 to 5. In addition, in the comparative examples, [A] liquid was used in place of [C] liquid, so the final amount of [A] liquid used was [A] liquid + [C] liquid.

Examples 52 to 97 and Comparative Examples 26 to 39 (Preparation of Thermal Recording Paper)
The coating solutions of the recording materials obtained in Examples 4 to 51 and Comparative Examples 11 to 25 were each coated on a piece of fine paper having a basis weight of 50 g/ ^m2 so that the coating weight when dried was the amount shown in Table 12, and then dried to prepare thermal recording papers of the present invention and comparative examples. The water resistance, plasticizer resistance, oil resistance, and alcohol resistance were evaluated as follows.

(Water resistance evaluation)
Using a thermal printer (TH-M2/PP) manufactured by Okura Engineering Co., Ltd., printing was performed on each of the thermal recording papers obtained in Examples 53 to 100 and Comparative Examples 41 to 55 with a pulse width of 1.4 msec, and the printed matter was immersed in water and left for 24 hours, then removed and dried. Using a colorimeter manufactured by X-Rite, product name "eXact", the reflection density of the colored part of the thermal recording paper before and after immersion was measured under the conditions of Illuminant C as the light source, Status A as the density standard, and a viewing angle of 2 degrees.
Reflection density after immersion/Reflection density before immersion×100
The remaining rate (%) of the colored portion was calculated using the formula above, and the water resistance was evaluated according to the following evaluation criteria. A higher remaining rate means better water resistance. The results are shown in Tables 15 and 16.
Evaluation criteria: A: Residual rate 100% or more; B: Residual rate 95% or more but less than 100%; C: Residual rate 90% or more but less than 95%; D: Residual rate less than 90%

(Plasticizer resistance evaluation)
Both the recording layer side and the back side of each thermal recording paper printed in the same manner as in the "Water Resistance Evaluation" were covered with a double layer of PVC wrap (product name: Denka Wrap Fresh, manufactured by Denka Polymer Co., Ltd.), and the paper was left at 40°C for 2.5 hours, after which the PVC wrap was removed. Using the same method and formula as in the "Water Resistance Evaluation of Thermal Recording Paper" above, the remaining rate (%) of the colored portion before and after leaving the paper at 40°C for 2.5 hours was calculated, and the plasticizer resistance was evaluated according to the following evaluation criteria. A higher remaining rate means better plasticizer resistance. The results are shown in Tables 15 and 16.
Evaluation criteria: A: Residual rate of 80% or more; B: Residual rate of 70% or more but less than 80%; C: Residual rate of 45% or more but less than 70%; D: Residual rate of less than 45%.

(Oil resistance evaluation)
Cottonseed oil (Tokyo Chemical Industry Co., Ltd.) was applied to the printed area of each thermal recording paper printed in the same manner as in the "Water Resistance Evaluation" above, and the paper was left at room temperature for 1.5 hours, after which the cottonseed oil was wiped off. Using the same method and formula as in the "Water Resistance Evaluation of Thermal Recording Paper" above, the remaining rate (%) of the colored area before and after leaving the paper at room temperature for 1.5 hours was calculated, and the oil resistance was evaluated according to the following evaluation criteria. A higher remaining rate means better oil resistance. The results are shown in Tables 15 and 16.
Evaluation criteria: A: Residual rate of 80% or more; B: Residual rate of 70% or more but less than 80%; C: Residual rate of 50% or more but less than 70%; D: Residual rate of less than 50%.

(Alcohol resistance evaluation)
Each thermal recording paper printed in the same manner as in the "Water Resistance Evaluation" was immersed in a 20% ethanol aqueous solution, left at room temperature for 2 hours, and then removed and dried. Using the same method and formula as in the "Water Resistance Evaluation of Thermal Recording Paper" above, the remaining percentage (%) of the colored portion before and after being left at room temperature for 2 hours was calculated, and the alcohol resistance was evaluated according to the following evaluation criteria. A higher remaining percentage means better alcohol resistance. The results are shown in Tables 15 and 16.
Evaluation criteria: A: Residual rate 100% or more; B: Residual rate 85% or more but less than 100%; C: Residual rate 70% or more but less than 85%; D: Residual rate less than 70%.

The results of the water resistance test, plasticizer resistance test, oil resistance test and alcohol resistance test are summarized in Tables 15 and 16 below. A rating of D indicates that the performance is insufficient for practical use and that it is difficult to use in applications where the material is exposed to the corresponding conditions. From the results in Tables 15 and 16, it is clear that the thermal recording paper of the example using the compound of the present invention is superior in all of the categories of water resistance, plasticizer resistance, oil resistance and alcohol resistance, and there is no bias, compared to the thermal recording paper of the comparative example using a commonly used color developer alone.

Examples 98 to 99 and Comparative Example 40 (Preparation of Thermal Recording Paper)
The coating solutions of the recording materials obtained in Examples 37 to 38 and Comparative Example 25 were each coated on a fine paper having a basis weight of 50 g/ ^m2 so that the coating weight when dried was the amount shown in Table 12, and then dried to prepare thermal recording papers of the present invention and Comparative Examples. The plasticizer resistance and oil resistance were evaluated as follows.

(Plasticizer resistance evaluation)
Both the recording layer side and the back side of each of the thermosensitive recording papers of Examples 97, 98 and Comparative Example 40 printed in the same manner as in the "Water Resistance Evaluation" were covered with a double layer of PVC wrap (product name: Denka Wrap Fresh, manufactured by Denka Polymer Co., Ltd.), and the paper was left at 45°C for 24 hours, after which the PVC wrap was removed. Using the same method and formula as in the "Water Resistance Evaluation of Thermosensitive Recording Paper" above, the residual rate (%) of the colored portion before and after leaving the paper at 45°C for 24 hours was calculated, and the plasticizer resistance was evaluated according to the following evaluation criteria. A higher residual rate means better plasticizer resistance. The results are shown in Table 17.
Evaluation criteria: A: Residual rate 60% or more B: Residual rate 50% to less than 60% C: Residual rate less than 50%

(Oil resistance evaluation)
Cottonseed oil (Tokyo Chemical Industry Co., Ltd.) was applied to the printed area of each of the thermal recording papers of Examples 97, 98 and Comparative Example 40, which had been printed in the same manner as in the "Water Resistance Evaluation" above, and after leaving the paper at room temperature for 24 hours, the cottonseed oil was wiped off. Using the same method and formula as in the "Water Resistance Evaluation of Thermal Recording Paper" above, the residual rate (%) of the colored area before and after leaving the paper at room temperature for 24 hours was calculated, and the oil resistance was evaluated according to the following evaluation criteria. A higher residual rate means better oil resistance. The results are shown in Table 17.
Evaluation criteria: A: Residual rate 60% or more B: Residual rate 50% to less than 60% C: Residual rate less than 50%

The results in Table 17 show that the thermal recording paper of the example using the compound of the present invention has superior plasticizer resistance and oil resistance when exposed to plasticizers and oils for a long period of time, compared to the thermal recording paper of the comparative example using only the color developer represented by formula (17).

Claims (11)

The following general formula (1)

(In general formula (1), R ₁ represents a linear or branched alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 14 carbon atoms. R ₂ represents a hydrogen atom, or a linear or branched alkyl group having 1 to 4 carbon atoms.)
A compound represented by the formula: The following general formula (2)

(In formula (2), _R3 represents a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, a linear or branched alkoxy group having 1 to 4 carbon atoms, a cyano group, or a halogen atom, and n represents an integer of 1 to 5.)
A compound represented by the formula: A recording material containing the compound according to claim 1 or claim 2. The recording material according to claim 3, further comprising a color developer. The developer is N-(2-(3-phenylureido)phenyl)benzenesulfonamide (formula (3) below), 3-(3-phenylureido)phenyl=4-methylbenzenesulfonate (formula (4) below), 3-(3-tosylureido)phenyl=4-methylbenzenesulfonate (formula (5) below), 1,3-diphenylurea (formula (6) below), 3-(3-phenylureido)benzenesulfonamide (formula (7) below), N ¹ ,N ³ 5. The recording material according to claim 4, which is any one or more of the compounds represented by the following formula (8), 3,3'-di-m-tolyl-5-(N-(m-tolyl)sulfamoyl)isophthalamide (formula (8) below), 3,3'-diallyl-4,4'-dihydroxydiphenyl sulfone (formula (9) below), 4,4'-dihydroxydiphenyl sulfone (formula (10) below), 4-hydroxy-4'-isopropoxydiphenyl sulfone (formula (11) below), 4-allyloxy-4'-hydroxydiphenyl sulfone (formula (12) below), 2,4'-dihydroxydiphenyl sulfone (formula (13) below), 2,2-bis(4-hydroxyphenylpropane) (formula (14) below), N-(2-(3-phenylureido)phenyl)acetamide (formula (15) below), 4,4'-bis(3-tosylureido)diphenylmethane (formula (16) below), and the compounds represented by the following formula (17).

A heat-sensitive recording layer comprising the recording material according to claim 3. A heat-sensitive recording layer comprising the recording material according to claim 4. A thermal recording paper having the thermal recording layer according to claim 6. A thermal recording paper having the thermal recording layer according to claim 7. An ink containing the recording material according to claim 3. An ink containing the recording material according to claim 4.