JP2001018534A - Thermosensitive recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermosensitive recording material which presents an image excellent in high shelf stability of an image part and in resistances to a plasticizer and oil, in particular. SOLUTION: In a thermosensitive recording material having on a substrate a thermosensitive color developing layer constituted mainly of leuco dye and a developer developing the leuco dye in heating, a compound expressed by the formula is used as the developer. In the formula, X denotes a bivalent functional group, Y an alkyl, aralkyl or aryl group and R a hydrogen atom or an alkyl, nitro, carboxyl or hydroxyl group.

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 having excellent image storability.

[0002]

2. Description of the Related Art A thermosensitive recording material generally comprises a support provided with a thermosensitive coloring layer mainly comprising an electron-donating colorless or light-colored dye precursor and an electron-accepting developer. By heating with a head, hot pen, laser light, etc.,
A dye precursor and a developer react instantaneously to obtain a recorded image. Japanese Patent Publication No. 43-4160, Japanese Patent Publication No. Sho 4
It is disclosed in JP-A-5-14039. Such a heat-sensitive recording material has advantages such that recording can be obtained with a relatively simple device, maintenance is easy, and noise is less generated.In recent years, computers, facsimile machines, ticket vending machines, label printers, It is used in a wide range of fields as recording materials for recorders and the like.

However, a heat-sensitive recording material using such an electron-donating dye precursor and an electron-accepting color developer has excellent properties such as good appearance, good touch, and high color density. On the other hand, the recorded image area comes into contact with plastics such as polyvinyl chloride, etc., and is decolorized by plasticizers and additives contained in the plastics, or comes into contact with chemicals contained in foods, cosmetics, etc. In addition, there is a disadvantage that the storage stability as a recording material is inferior, for example, the recorded image portion is easily decolored or the background portion is colored.

[0004] As means for realizing high storage stability of recorded images, use of a highly reliable color developer has been conventionally proposed. For example, JP-A-58-82788 and JP-A-60-13852 propose phenol sulfone compounds, and JP-A-62-169681 proposes substituted salicylic acid compounds. When a compound is used as a color developer, the fastness of the image area to a plasticizer, oil and the like is insufficient. Further, as a compound for overcoming the high plasticizer resistance of an image, JP-A-9-26756
No. 6 proposes a diamic acid derivative and a metal salt thereof. Even these compounds were not at satisfactory levels.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-sensitive recording material having high preservability of an image area, particularly excellent plasticizer resistance and oil resistance, in view of the above-mentioned prior art. is there.

[0006]

According to the present invention, there is provided a heat-sensitive recording material having a heat-sensitive color-forming layer comprising, as a main component, a leuco dye and a color developing agent for developing the leuco dye upon heating. A heat-sensitive recording material is provided wherein at least one compound represented by the following general formula (1) is used as a color developer.

Embedded image (Wherein, X represents a divalent functional group, Y represents an alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, and R represents a hydrogen atom, an alkyl group, a nitro group, a carboxyl group. , Represents a hydroxyl group.)

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

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In the compound represented by the general formula (1) used as a color developer in the present invention, the divalent group represented by X is a carbonyl group, a sulfonyl group, an aromatic hydrocarbon or an aliphatic hydrocarbon. A derived divalent group, one or more heteroatoms in the main chain, a carbonyl group, a sulfonyl group,
Ester bond, divalent group derived from an aliphatic hydrocarbon containing an aromatic ring, at least one hetero atom, carbonyl group, sulfonyl group, ester bond, alkylene, aliphatic containing a hetero atom in the main chain And a divalent group derived from two aromatic hydrocarbons linked by a hydrocarbon.

Further specific examples include the following functional groups. An alkylene group having 2 to 12 carbon atoms, a phenylene group,
Xylylene group,

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Further, as the group represented by Y represented by the general formula (1), an alkyl group having 1 to 4 carbon atoms, a benzyl group,
Examples include a hydroxybenzyl group and a phenyl group.

In the present invention, a compound represented by the general formula (2) wherein R is a hydrogen atom is preferred as a compound represented by the general formula (1). This compound has a particularly remarkable effect on the above-mentioned problems.

Embedded image (In the formula, X and Y are the same as those in the general formula (1).)

Specific examples of the compound represented by the general formula (1) or (2) of the present invention include the following (Tables 1 to 6), but the present invention is not limited thereto. It is not something to be done.

[0013]

[Table 1]

[0014]

[Table 2]

[0015]

[Table 3]

[0016]

[Table 4]

[0017]

[Table 5]

[0018]

[Table 6]

The basic dye precursor (leuco dye) used in the present invention can be used alone or as a mixture of two or more kinds. As such a leuco dye, those applied to a heat-sensitive material are optional. For example, the following can be mentioned. 3,3-bis (p-dimethylaminophenyl) phthalide, 3,3-
Bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3-diethylamino-6-methyl-7-
Anilinofluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3-N-methyl-N-butylamino-6-methyl-7-anilinofluoran, 3-
N-methyl-N-propylamino-6-methyl-7-anilinofluoran, 3-N-ethyl-N-propylamino-6-methyl-7-anilinofluoran, 3-N-methyl-N- Amylamino-6-methyl-7-anilinofluoran, 3-N-ethyl-N-amylamino-6-methyl-7-anilinofluoran, 3-N-ethyl-N-
Isoamylamino-6-methyl-7-anilinofluoran, 3-N-hexyl-N-isoamylamino-6-methyl-7-anilinofluoran, 3-N-methyl-N-
Cyclohexylamino-6-methyl-7-anilinofluoran, 3-N-ethyl-N-furanylmethylamino-
6-methyl-7-anilinofluoran, 3-diethyl-
N-butylamino-7- (2′-fluoroanilino) fluoran, 3-pyrrodilyl-7-dibenzylaminofluoran, 3-bis (diphenylamino) fluoran, 3
-Diethylamino-7- (2'-chloroanilino) fluoran, 3-diethylamino-6-chloro-7-anilinofluoran, 3-dibutylamino-7- (2'-chloroanilino) fluoran, 3-diethylamino-7-chloro Fluoran, 3-diethylamino-6-methyl-7
-Chlorofluorane, 3-N-methyl-N-cyclohexylamino-6-chlorofluoran, 3-diethylamino-6-methyl-7- (2 ', 4'-dimethylanilino) fluoran, 3-diethylamino-7 -Dibenzylaminofluoran, 3-butylamino-7- (2'-chloroanilino) fluoran, 3-diethylamino-6-
Ethoxyethyl-7-anilinofluoran and the like.

In the present invention, in addition to being used alone as a color developer, it can be used in combination with a conventionally known color developer and used for other purposes such as a sensitizer.
Specific examples of conventionally known color developers used at that time include the following. 4,4'-isopropylidenebisphenol, 4,4'-isopropylidenebis (o
-Methylphenol), 4,4'-sec-butylidenebisphenol, 4,4'-isopropylidenebis (2
-Tert-butylphenol), zinc p-nitrobenzoate, 1,3,5-tris (4-tert-butyl-3)
-Hydroxy-2,6-dimethylbenzyl) isocyanuric acid, 2,2- (3,4-dihydroxyphenylpropane), bis (4-hydroxy-3-methylphenylsulfide), 4- (β- (p- Methoxyphenoxy) ethoxy) salicylic acid, 1,7-bis (4-hydroxyphenylthio) -3,5-dioxaheptane, monobenzyl phthalate monocarboxylic acid, 4,4′-cyclohexylidenebisphenol, 4,4 '-Isopropylidenebis (2-chlorophenol), 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 4,4'-butylidenebis (6-tert-butyl-2-methyl) phenol, , 1,3-Tris (2
-Methyl-4-hydroxy-5-cyclohexyl) butane, 4,4'-thiobis (6-tert-butyl-2-
Methyl phenol) 4,4′-diphenol sulfone,
4-benzyloxy-4'-hydroxydiphenylsulfone, 4-isopropyloxy-4'-hydroxydiphenylsulfone, 4,4'-diphenolsulfoxide, isopropyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, benzyl protocatechuate , Stearyl gallate, 1,3-bis (4-hydroxyphenylthio) propane, 1,3-bis (4-hydroxyphenylthio) -2-hydroxypropane, N, N-diphenylthiourea, N, N-di (M-chlorophenylthiourea), salicylanilide, 5-chlorosalicylanilide, methyl bis (4-hydroxyphenyl) acetate, benzyl bis (4-hydroxyphenyl) acetate, 1,3-bis (4-hydroxycumyl) ) Benzene, 1,4-bis (4-h Rokishikumiru) benzene,
2,4'-diphenol sulfone, 2,2'-diallyl-4,4'-diphenol sulfone, 3,4-dihydroxy-4'-methyldiphenyl sulfone, α, α-bis (4-hydroxyphenyl)- α-methyltoluene,
4,4′-thiobis (2-methylphenol), 4,
4'-thiobis (2-chlorophenol) and the like.

In the present invention, various heat-fusible substances can be used alone or as a mixture of two or more kinds as a sensitivity improver and a lubricant. Specific examples thereof include the following. Fatty acids such as stearic acid and behenic acid, fatty acid amides such as stearic acid amide and palmitic acid amide, zinc stearate, aluminum stearate, calcium stearate, zinc palmitate,
Metal salts of fatty acids such as zinc behenate, p-benzylbiphenyl, terphenyl, triphenylmethane, benzyl p-benzyloxybenzoate, β-benzyloxynaphthalene, β-naphthoic acid phenyl, 1-hydroxy-2-
Phenyl naphthoate, methyl 1-hydroxy-2-naphthoate, diphenyl carbonate, benzyl terephthalate, 1,4-dimethoxynaphthalene, 1,4-diethoxynaphthalene, 1,4-dibenzyloxynaphthalene,
1,2-diphenoxyethane, 1,2-bis (4-methylphenoxyethane), 1,4-diphenoxy-2-butene, 1,2-bis (4-methoxyphenylthio) ethane, dibenzoylmethane, 1,4-diphenylthiobutane, 1,4-diphenylthio-2-butene, 1,3-bis (2-vinyloxyethoxy) benzene, 1,4-bis (2-vinyloxyethoxy) benzene, p- (2 −
Vinyloxyethoxy) biphenyl, p-aryloxybiphenyl, dibenzoyloxymethane, dibenzoyloxypropane, dibenzyldisulfide, 1,1-
Diphenylethanol, 1,1-diphenylpropanol, p-benzyloxybenzyl alcohol, 1,3-
Phenoxy-2-propanol, N-octadecylcarbamoyl-p-methoxycarbonylbenzene, N-octadecylcarbamoylbenzene, 1,2-bis (4-methoxyphenoxy) propane, 1,5-bis (4-methoxyphenoxy) -3- Oxapentane, dibenzyl oxalate, bis (4-methylbenzyl) oxalate, bis (4-chlorobenzyl) oxalate, 1,4-diacetylbenzene, 4-acetylbiphenyl, 4-propionylbiphenyl, 3,4,5- Trimethoxybenzoic acid, 3,
Methyl 4,5-trimethoxycinnamate, N-benzylsuccinimide, N- (2-methylphenyl) -succinimide, NO-dibenzoyl-2-aminoethanol, NO-di-p-toluene Sulfonyl-2-aminoethanol, p-toluenesulfonic acid phenoxyethyl ester, benzenesulfonic acid phenoxyethyl ester, diphenylcarbamate, 2-chloroacetoacetanilide, hippuric acid 4-methylbenzyl ester, 1,4
-Dihydroxybenzene dimethyl carbonate, 4,
4′-dihydroxydiphenylsulfone dimethyl carbonate, N-benzylidenebenzhydrazide, N-benzylidene-p-toluenesulfonylhydrazide, 1-phenyl-2-methylsulfonylanethanone, 1-phenyl-2-phenylsulfonylanethanone, 1- ( 4-methylphenyl) -2-methylsulfonylanethanone, 4-phenyl-4-oxobutanoic acid methyl ester, 4- (4-
Methylphenyl) -4-oxobutanoic acid isopropyl ester, 4- (4-methylphenyl) -4-oxobutanoic acid benzyl ester and the like.

In preparing the heat-sensitive recording material of the present invention, in addition to the above-described developer, leuco dye, and heat-fusible substance, various materials commonly used for forming the heat-sensitive recording material are used. It can be used as appropriate. Examples thereof include binders for binding various materials on a support or the like in the heat-sensitive recording layer, and these can be used alone or in combination of two or more. Are as follows.

Polyvinyl alcohol, modified polyvinyl alcohol, starch and its derivatives, methoxycellulose,
Hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose, cellulose derivatives such as ethyl cellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylamide / acrylate copolymer,
Acrylamide / acrylic ester / methacrylic acid terpolymer, styrene / maleic anhydride copolymer alkali salt, isobutylene / maleic anhydride copolymer alkali salt, polyacrylamide, modified polyacrylamide,
Water-soluble polymers such as methyl vinyl ether / maleic anhydride copolymer, carboxy-modified polyethylene, polyvinyl alcohol / acrylamide block copolymer, melamine-formaldehyde resin, urea-formaldehyde resin, sodium alginate, gelatin, casein, polyvinyl acetate, Polyurethane, styrene / butadiene copolymer, styrene / butadiene / acrylic copolymer, polyacrylic acid, polyacrylate, polymethacrylate, vinyl chloride / vinyl acetate copolymer, polybutyl methacrylate, polyvinyl butyral, polyvinyl Emulsions such as acetal and ethylene / vinyl acetate copolymer.

These may be used alone or as a mixture, and may be cured by adding a crosslinking agent (curing agent) if necessary. The crosslinking agent (curing agent) in this case reacts with the binder, and examples thereof include a glyoxal derivative, a methylol derivative, an epichlorohydrin derivative, an epoxy compound, and an aziridine compound.

Specific examples of the pigment used alone or in combination of two or more in the heat-sensitive recording material include the following. Inorganic fine powders such as silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, kaolin, calcined kaolin, talc, and surface-treated silica. Organic fine powders such as urea-formalin resin, styrene / methacrylic acid copolymer, polystyrene resin, vinylidene chloride resin, styrene / acrylic copolymer, and plastic hollow hollow fine particles.

Further, the heat-sensitive recording material of the present invention may optionally contain a pigment, a binder, a crosslinking agent, a lubricant, etc. on the heat-sensitive coloring layer for the purpose of improving the head matching property and the writing property on the recording material. It is possible to provide a protective layer as a component,
In this case, as the pigment, binder, crosslinking agent, and lubricant, the above-described pigment, binder, crosslinking agent, and lubricant (a heat-fusible substance) can be used alone or in combination of two or more.

In the present invention, the general formula (1)
Or a compound represented by (2) the content of the case of using the heat-sensitive coloring layer, 1 to 10 g / m ² in dry weight, preferably is 1 to 5 g / m ² suitably.

In the present invention, an undercoat layer containing a pigment, a binder and the like as a main component can be provided between the support and the thermosensitive coloring layer. The undercoat layer functions as a heat insulating layer, and improves sensitivity by efficiently utilizing thermal energy from a thermal head or the like. As the pigment and the binder resin constituting the undercoat layer, the above-mentioned pigments and binder resins can be used alone or in combination of two or more. In this case, it is desirable to use plastic spherical hollow fine particles as the pigment.

The above-mentioned "plastic spherical hollow fine particles" are fine hollow particles having a thermoplastic resin as a shell, containing air or other gas therein and already in a foamed state, and having an average particle diameter of 0. 0.2 to 20 μm. If the average particle diameter (particle diameter) is smaller than 0.2 μm, there is a problem in production such as difficulty in obtaining an arbitrary hollow ratio, and there is a problem in cost.
When the particle size is larger than m, the surface smoothness after coating and drying is reduced, so that the adhesion to the thermal head is reduced and the effect of improving the thermal sensitivity is reduced. Therefore, it is preferable that the particles have a particle diameter in the above-mentioned range and a small variation in the particle diameter.

Further, in consideration of the heat insulating effect, the hollow spherical particles of the plastic preferably have a hollow ratio of 40% or more, more preferably 90% or more. When the hollow ratio is low, the heat energy from the thermal head is released to the outside of the heat-sensitive recording material through the support because the heat insulating effect is insufficient, and the effect of improving the thermal sensitivity is poor. Here, the "hollow ratio" is a ratio of the outer diameter to the inner diameter of the hollow fine particles, and is represented by the following formula. Hollow ratio (%) = (inner diameter of hollow fine particles) / (outer diameter of hollow fine particles) × 100

As described above, the plastic hollow spherical fine particles have a thermoplastic resin as a shell. Examples of the resin include polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyacrylate, and polyacrylate. Examples thereof include acrylonitrile, polybutadiene, and copolymer resins thereof. Among these, a copolymer resin mainly containing vinylidene chloride and acrylonitrile is particularly preferable.

In the present invention, the binder resin used for forming the undercoat layer is appropriately selected from conventionally known water-soluble polymers and / or aqueous polymer emulsions. Specific examples thereof include, as water-soluble polymers, for example, polyvinyl alcohol, starch and derivatives thereof, methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose,
Cellulose derivatives such as ethyl cellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylamide / acrylate copolymer, acrylamide / acrylate / methacrylic acid terpolymer, styrene / maleic anhydride copolymer alkali salt, isobutylene / Maleic anhydride copolymer alkali salt, polyacrylamide,
Examples include sodium alginate, gelatin, casein and the like. Examples of the aqueous polymer emulsion include latexes such as styrene / butadiene copolymer and styrene / butadiene / acrylic copolymer, vinyl acetate resin, vinyl acetate / acrylic acid copolymer, and styrene / acrylic ester copolymer. And emulsions of acrylate resin, polyurethane resin and the like.

In the undercoat layer, together with the plastic spherical hollow fine particles and the binder resin, if necessary, auxiliary additives commonly used in this type of heat-sensitive recording material, for example, fillers, heat-fusible materials, etc. Substances, surfactants, pressure coloring inhibitors and the like can be used in combination. In this case, specific examples of the filler and the heat-fusible substance include those described above in relation to the heat-sensitive coloring layer component. When plastic spherical hollow fine particles are used for the undercoat layer, other inorganic pigments can be added for the purpose of improving the matching property with the thermal head.

A layer containing a pigment, a binder, a heat-fusible substance and the like can be provided as an intermediate layer between the undercoat layer and the thermosensitive coloring layer, if necessary. Furthermore,
The heat-sensitive recording material of the present invention improves the head matching property at the time of printing, improves the storage stability of the recorded image, and improves the writing property on the recording material and the printing property.
It is also possible to provide a protective layer on the thermosensitive coloring layer. In this case, as the components constituting the protective layer, the above-mentioned filler, binder resin, heat-fusible substance and the like can be used.

In the heat-sensitive recording material of the present invention, a back layer mainly composed of a pigment, a binder resin, a crosslinking agent and the like can be provided on the back surface of the support. Also in this case, the pigment, the binder resin, and the lubricant (a heat-fusible substance) are used as the pigment, the binder resin, and the lubricant.

As a support of the heat-sensitive recording material of the present invention,
In addition to ordinary paper (acidic paper, neutral paper), it is possible to arbitrarily use one that can be applied and processed, for example, synthetic paper,
Polymer films and the like can be mentioned.

In addition, in obtaining the heat-sensitive recording material of the present invention, in addition to the above, additional components commonly used in this type of heat-sensitive recording material, for example, a surfactant, a pressure-coloring inhibitor and the like can be used in combination. .

The heat-sensitive recording material of the present invention can be used in any field where a heat-sensitive recording material is conventionally used. Specific examples include facsimile paper, food POS labels, industrial barcode labels, linerless labels, ticket paper, magnetically attached paper, CAD paper, and transparent sensitivity films.

It is not clear why the heat-sensitive recording material using the compound represented by the general formula (1) or (2) has high plasticizer resistance and high oil resistance. It is considered to have contributed. When two or more aromatic carboxylic acids are contained in one molecule, the molecular weight increases, and the solubility in nonvolatile solvents such as oils and plasticizers decreases. By having a secondary amide group as a partial structure in the molecule, compatibility with the dye is improved.

[0040]

Next, the heat-sensitive recording material of the present invention will be described in more detail with reference to examples. The following parts and percentages are all based on weight.

Synthesis Example 1 (Synthesis of Specific Example Compound 7) 15 g of phthalic anhydride was dispersed in 200 ml of acetic acid, and 18 g of 4,4-bis (N-benzylamino) diphenylmethane was added to the dispersion in three portions. And stirred at room temperature for 3 hours. The reaction mixture was poured into 1000 ml of water, stirred at room temperature, and the precipitated white crystals were filtered and washed with water. The white crystals were dispersed again in 1000 ml of water, and a 10% aqueous sodium hydroxide solution was added dropwise to dissolve the white crystals, followed by filtration. A 10% aqueous hydrochloric acid solution was added dropwise to the obtained filtrate to precipitate white crystals. The obtained white crystals were washed with water and dried under reduced pressure to obtain 18 g of white crystals.
The melting point was 126-131 ° C.

Synthesis Example 2 (Synthesis of Compound 9) 15 g of phthalic anhydride was dispersed in 200 ml of acetic acid, and 19 g of 4,4-bis (N-benzylamino) diphenyl sulfide was added to the dispersion in three portions. And at room temperature
Stirred for hours. The reaction mixture is poured into 1000 ml of water,
After stirring at room temperature, the precipitated white crystals were filtered and washed with water. The white crystals were dispersed again in 1000 ml of water, and 1
A 0% aqueous sodium hydroxide solution was added dropwise to dissolve the white crystals, followed by filtration. A 10% aqueous hydrochloric acid solution was added dropwise to the obtained filtrate to precipitate white crystals. The obtained white crystals were washed with water and dried under reduced pressure to obtain 19 g of white crystals.
Obtained. Melting point was 128-134 ° C.

Synthesis Example 3 (Synthesis of Compound 17) 15 g of phthalic anhydride was dispersed in 200 ml of acetic acid, and 19 g of 4,4-bis ((N- (P-hydroxybenzylamino)) diphenylmethane was added to the dispersion. The reaction mixture was stirred at room temperature for 3 hours.
The mixture was added to 0 ml, stirred at room temperature, and the precipitated white crystals were filtered and washed with water. This white crystal was again subjected to 1000 m of water.
and 10% aqueous sodium hydroxide solution was added dropwise to dissolve the white crystals, followed by filtration. A 10% aqueous hydrochloric acid solution was added dropwise to the obtained filtrate to precipitate white crystals. The obtained white crystals were washed with water and dried under reduced pressure to obtain 19 g of white crystals. Melting point was 193-198 ° C.

Example 1 A mixture having the following composition was dispersed in a magnetic ball mill [A
Liquid] to [liquid D]. [Solution A] 3-N, N-dibutylamino-6-methyl-7-anilinofluoran 10 parts 10% aqueous solution of polyvinyl alcohol 10 parts Water 30 parts [Solution B] Specific compound 7 10 parts 10% aqueous solution of polyvinyl alcohol 10 parts Water 30 parts [liquid C] P527 (silica gel manufactured by Mizusawa Chemical) 10 parts 10% aqueous solution of polyvinyl alcohol 10 parts water 30 parts [liquid D] zinc stearate 10 parts 10% aqueous solution of polyvinyl alcohol 10 parts water 30 parts

Further, a mixture having the following composition was stirred and dispersed with a disper to prepare a solution E. [E Solution] Non-foamable plastic micro hollow particles (solid content 24%, average particle size 3 μm, hollowness 90%) 40 parts Styrene / butadiene copolymer latex 10 parts Water 50 parts

Next, a coating solution for the thermosensitive coloring layer and a coating solution for the undercoat were prepared in the following mixing ratio using [Solution A] to [Solution E]. (Thermosensitive coloring layer coating solution) [Solution A]: [Solution B]: [Solution C]: [Solution D] = 1: 4:
4: 0.5 (undercoat coating liquid) [E liquid]: [C liquid] = 2: 1

<Coating of Each Layer> Commercial high quality paper (basis weight 60 g)
/ M ² ) (undercoat coating solution) was applied and dried to a dry weight of 3 g / m ² to obtain an intermediate coated paper (paper coated with an undercoat layer). On the undercoat layer, a thermosensitive coloring layer coating solution was applied and dried such that the dry weight of the leuco dye was 0.5 g / m ² to form a thermosensitive coloring layer. Thereafter, calendering was performed at a pressure of 10 kg / cm ² to obtain a heat-sensitive recording material of the present invention.

Example 2 A thermosensitive recording material was obtained in the same manner as in Example 1 except that the specific compound 9 was used in place of the specific compound 7 in the [solution B] of Example 1.

Example 3 A heat-sensitive recording material was obtained in the same manner as in Example 1 except that the specific compound 17 was used in place of the specific compound 7 in [B solution] of Example 1.

Comparative Example 1 The procedure of Example 1 was repeated, except that 2,2-bis (4-hydroxyphenyl) propane (bisphenol A) was used in place of compound 7 of Example 1. In the same manner, a thermosensitive recording material was obtained.

Comparative Example 2 A heat-sensitive recording material was prepared in the same manner as in Example 1 except that 4-hydroxy-4'-isopropoxydiphenylsulfone was used in place of Compound 7 in Example B [Solution B]. I got

The following test was performed on the heat-sensitive recording material prepared as described above. Table 2 shows the results. Head power 0.68 W / dot, 1-line recording time 10 ms / line, scanning line density 8 × 3.85 dots /
mm with a pulse width of 0.9 ms, and the printed image area is printed with PVC wrap film (Shin-Etsu Polymer)
Were placed on each other, and the image density was measured with a Macbeth densitometer, and the plasticizer resistance was evaluated. In addition, cotton seed oil was applied to the test piece printed in the same manner, and the image density after standing at 40 ° C. for 16 hours was measured with a Macbeth densitometer to evaluate oil resistance.

[0053]

[Table 7] From the results in Table 2, it is clear that the heat-sensitive recording material of the present invention is excellent in plasticizer resistance and oil resistance of an image.

[0054]

The heat-sensitive recording material of the present invention has a heat-sensitive coloring layer using the compound represented by the formula (1) or (2) as a color developer.
It has excellent oil resistance.

Claims (2)

[Claims] 1. A thermosensitive recording material having a thermosensitive coloring layer comprising, as a main component, a leuco dye and a color developing agent for coloring the leuco dye on heating on a support, wherein the color developing agent is represented by the following general formula (1) A heat-sensitive recording material comprising at least one compound represented by the formula (1): Embedded image (Wherein, X represents a divalent functional group, Y represents an alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, and R represents a hydrogen atom, an alkyl group, a nitro group, a carboxyl group. , Represents a hydroxyl group.) 2. The developer according to claim 1, wherein the color developer is at least one compound represented by the following general formula (2).
The heat-sensitive recording material as described. Embedded image (In the formula, X represents a divalent functional group, and Y represents an alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group.)