JPH1178252A - Thermal recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal recording material excellent in color forming properties, reduced in background fog against heat and excellent in plasticizer resistance and oil resistance. SOLUTION: In a thermal recording material wherein a thermal color forming layer based on a colorless or light-colored color forming compd. and a coupling compd. capable of allowing the color forming compd. to form a color at a time of heating is provided on a support, 2,4'-dihydroxydiphenylsulfone as the coupling compd., 2-(2'-hydroxy-5'-methylphenyl)benzotriazole as a hot-melt compd. (sensitizer) and synthetic paraffin wax as a stabilizer are added to the thermal color forming layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a heat-sensitive recording material. More specifically, the present invention relates to a heat-sensitive recording material which has excellent coloring properties, has little background fogging, and has good storage stability such as plasticizer resistance and oil resistance.

[0002]

2. Description of the Related Art A thermosensitive recording material is prepared by separately dispersing a developer such as a leuco dye and a phenolic substance into fine particles, and then mixing the two, and then adding a binder, a sensitizer, a filler, Additives such as lubricants to form a coating solution, applied to a support such as paper, film, synthetic paper, etc.The chemicals that occur when one or both of the leuco dye and the developer are melted and contacted by heating A color recording is obtained by the reaction, and a sheet-like thermosensitive recording material is usually prepared. A thermal printer with a built-in thermal head or the like is used for coloring the heat-sensitive recording sheet. This thermal recording method has the following advantages: (1) no noise is produced during recording,
(2) No need for development and fixing, (3) Maintenance-free, (4) Relatively inexpensive machines, etc., the facsimile field, computer output, printer field such as calculator, medical measurement Widely used in the field of recorders, automatic ticket vending machines, and labels for heat-sensitive recording.

[0003] Among these fields of use, the use of labels for POS systems in retail stores, supermarkets, and the like, and the use of station automation systems for tickets are increasing. In these applications, it is desired to further improve the storability of a color image.

In recent years, the demand for high-speed recording has been further increased, and the development of a heat-sensitive recording material capable of sufficiently coping with high-speed recording has been strongly desired. The disadvantage of fogging is more likely to appear. Conventionally, various methods have been proposed to improve thermal responsiveness and further improve image storability, but a satisfactory method has not yet been established.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the disadvantages of the prior art. That is, it is an object of the present invention to provide a heat-sensitive recording material that has high sensitivity, has little background fogging, and has good storage stability such as plasticizer resistance and oil resistance.

[0006]

Means for Solving the Problems The present inventors have made various studies to achieve the above object, and as a result, completed the present invention. That is, the present invention relates to (1) a heat-sensitive recording material comprising a support provided with a colorless or pale-colored color-forming compound and a heat-sensitive color-forming layer containing, as a main component, a color-developing compound capable of coloring the color-forming compound when heated. And 2,4 ′ as the color-developing compound.
-That dihydroxydiphenyl sulfone is contained in a heat-sensitive color-forming layer containing 2- (2'-hydroxy-5'-methylphenyl) benzotriazole as a heat-fusible compound (sensitizer) and synthetic paraffin wax as a stabilizer; (2) a heat-sensitive recording material according to (1), wherein the melting point of the synthetic paraffin wax is 100 to 130 ° C .; and (3) an intermediate layer between the heat-sensitive coloring layer and the support. The present invention relates to the heat-sensitive recording materials (1) and (2), which are provided.

[0007]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, 2,4'-dihydroxydiphenylsulfone is used as a color-forming compound and a color-developing compound, and 2- (2'-hydroxy-) is used as a sensitizer.
5'-methylphenyl) benzotriazole, synthetic paraffin wax as a main component as a stabilizer, and thermosensitive coloring with a binder and other necessary fillers, heat-soluble compounds, lubricants, surfactants and the like as shown below. The layers are adjusted. 2,4′- based on 1 part by weight of the color-forming compound
Dihydroxydiphenyl sulfone is 0.5 to 10 parts by weight, preferably 1 to 5 parts by weight, and 2- (2'-hydroxy-5'-methylphenyl) benzotriazole is 0.1 to 10 parts by weight.
5 to 20 parts by weight, preferably 2 to 10 parts by weight, synthetic paraffin wax 0.1 to 10 parts by weight, preferably 0.1 to 10 parts by weight.
5 to 5 parts by weight are suitable. In forming the thermosensitive coloring layer in the present invention, the coloring compound is 1 to 50% by weight, and 2,4′-dihydroxydiphenyl sulfone is 1 to 5% by weight.
50% by weight, 2 to 40% by weight of 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 1 to 30% by weight of synthetic paraffin wax, and 1 to 9 of binder
0% by weight, the filler and the heat-fusible compound are each 0 to 80% by weight, and the other lubricants, surfactants, etc. are each in an arbitrary ratio,
For example, each is used in an amount of 0 to 30% by weight. The weight% is the weight ratio of each component in the thermosensitive coloring layer.

The synthetic paraffin wax used in the present invention is a synthetic wax obtained by a Fischer-Tropsch synthesis method or the like. Among these, the appearance is a white liquid, and the average molecular weight is 100 to 2,000, preferably 6
Those having properties of from 00 to 800 and a melting point of from 100 to 130 ° C are preferred. Incidentally, synthetic paraffin wax is generally C _n H
It is a compound represented by the chemical formula of _{2n + 2} .

In the present invention, the amount of the above-mentioned material to be applied on the support or the intermediate layer provided on the support is 1 to 40 g / m ² , preferably 5 to 15 g / m ² in dry weight. To form a thermosensitive coloring layer.
Further, a protective layer or the like can be provided on the thermosensitive coloring layer.

Examples of the color-forming compound used in the heat-sensitive coloring layer are not particularly limited as long as they are generally used for pressure-sensitive recording paper or heat-sensitive recording paper. As a specific example,
Examples include fluoran compounds, triarylmethane compounds, spiro compounds, diphenylmethane compounds, thiazine compounds, lactam compounds, and fluorene compounds.

The fluoran compounds include, for example, 3-
Diethylamino-6-methyl-7-anilinofluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3- (N-methyl-N-cyclohexylamino) -6-methyl-7-anilino Fluoran, 3- (N
-Ethyl-N-isopentylamino) -6-methyl-7
-Anilinofluoran, 3-isobutylethylamino-
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- (p-toluidine Noethylamino)
-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7- (p-toluidino) fluoran, 3-diethylamino-7- (o-chloroanilino)
Fluorane, 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-6-methyl-7-anilinofluoran, 3-diethylamino-6-chloro -7-ethoxyethylaminofluoran, 3-diethylamino-6-chloro-7-anilinofluoran, 3-diethylamino-
7-chlorofluorane, 3-diethylamino-6-chloro-7-methylfluoran, 3-diethylamino-7-
Methylfluoran, 3-diethylamino-7-octylaminofluoran, 3-diethylamino-7-phenylfluoran, 3- (p-toluidinoethylamino) -6
-Methyl-7-phenethylfluoran and the like.

Examples of the tolylmethane compound include 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (also known as crystal violet lactone or CVL) and 3,3-bis (p-dimethylamino). Phenyl) phthalide 3- (p-dimethylaminophenyl) -3- (1,2-dimethylaminoindole-3
-Yl) phthalide, 3- (p-dimethylaminophenyl) -3- (2-methylindol-3-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (2-
Phenylindol-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-dimethyl Aminophthalide, 3-p-dimethylaminophenyl-3- (1-
Methylpyrrole-2-yl) -6-dimethylaminophthalide and the like.

Examples of the spiro compounds include 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3,3'-dichlorospirodinaphthopyran,
Benzylspirodinaphthopyran, 3-propylspirobenzopyran, 3-methylnaphtho- (3-methoxybenzo) spiropyran, 1,3,3-trimethyl-6-nitro-8'-methoxyspiro (indoline-2,2'- Benzopyran) and the like, as diphenylmethane compounds, for example, N-halophenyl-leuco auramine,
4-bis-dimethylaminophenylbenzhydrylbenzyl ether, N-2,4,5-trichlorophenylleucouramine and the like; thiazine compounds such as benzoylleucomethylene blue and p-nitrobenzoylleucomethylene blue; Examples of the fluorene-based compound include rhodamine B anilinolactam and rhodamine B-p-chloroanilinolactam, and examples of the fluorene-based compound include 3,6-bis (dimethylamino) fluorenespiro (9,3 ′)-6. '-Dimethylaminophthalide, 3,6-bis (dimethylamino) fluorenespiro (9,3')-6'-pyrrolidinophthalide,
3-dimethylamino-6-diethylaminofluorenespiro (9,3 ')-6'-pyrrolidinophthalide and the like. These color-forming compounds are used alone or in combination of two or more.

In the present invention, examples of the binder that can be used in providing the intermediate layer, the thermosensitive coloring layer, and the protective layer include 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, polyvinylpyrrolidone, polyacrylamide, polyacrylic acid, starch and derivatives thereof, casein, gelatin, water-soluble isoprene rubber, styrene / maleic anhydride copolymer alkali salt, iso Water-soluble materials such as alkali salts of (or diiso) butylene / maleic anhydride copolymer or polyvinyl acetate, vinyl chloride / vinyl acetate copolymer, polystyrene Polyacrylate, polyurethane, styrene / butadiene (SB) copolymer, carboxylated styrene / butadiene (SB) copolymer, styrene / butadiene / acrylic acid-based copolymer, composite particles of colloidal silica and acrylic resin, etc. And the like.

Examples of the filler that can be used include calcium carbonate, magnesium carbonate, magnesium oxide, silica, white carbon, talc, clay, alumina, magnesium hydroxide, aluminum hydroxide, aluminum oxide, barium sulfate, polystyrene resin, and urea. Formalin resin and the like can be mentioned.

Examples of the heat-fusible compound that can be used include waxes such as animal and plant waxes and synthetic waxes, higher fatty acids, higher fatty acid amides, higher fatty acid anilides, acetylated aromatic amines, naphthalene derivatives, aromatic ethers, and the like. Aromatic carboxylic acid derivatives, aromatic sulfonic acid ester derivatives, carbonic acid or oxalic acid diester derivatives,
Biphenyl derivatives, terphenyl derivatives, and the like that are solid at room temperature and have a melting point of about 70 ° C. or more can be used.

Examples of waxes include wood wax, carnauba wax, shellac, paraffin, montan wax,
Paraffin oxide, polyethylene wax, polyethylene oxide and the like, as higher fatty acids, for example, stearic acid,
Examples of higher fatty acid amides such as behenic acid include stearic acid amide, oleic acid amide, N-methylstearic acid amide, erucic acid amide, methylolbehenic acid amide, methylolstearic acid amide, methylenebisstearic acid amide, and ethylenebisstearin Acid amides and the like; higher fatty acid anilides such as stearic acid anilide and linoleic acid anilide; acetylated aromatic amines such as acetotoluide; naphthalene derivatives such as 1-benzyloxynaphthalene and 2-benzyloxynaphthalene; Benzyloxynaphthalene, 1-hydroxynaphthoic acid phenyl ester and the like include aromatic ethers such as 1,2-diphenoxyethane, 1,4
-Diphenoxyethane, 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 and the like include aromatic carboxylic acid derivatives such as benzyl p-hydroxybenzoate,
Examples of aromatic sulfonic acid ester derivatives include benzyl p-benzyloxybenzoate and dibenzyl terephthalate, for example, p-toluenesulfonic acid phenyl ester, phenylmesitylene sulfonate,
-Methylphenyl mesitylenesulfonate and the like are carbonic acid or oxalic acid diester derivatives, for example, diphenyl carbonate, dibenzyl oxalate, dioxalate (4
-Methylbenzyl) ester, oxalic acid di (4-chlorobenzyl) ester and the like, as biphenyl derivatives,
For example, p-benzylbiphenyl, p-allyloxybiphenyl and the like are terphenyl derivatives such as m-
Terphenyl and the like are each exemplified.

Other additives such as a lubricant such as zinc stearate, calcium stearate, and aluminum stearate, a surfactant, an antifoaming agent, and an ultraviolet absorber are added as required.

When an intermediate layer is provided between the heat-sensitive color-forming layer and the support, the color-forming properties become better. The coating material for the intermediate layer is prepared by using the above-mentioned filler and binder as main components and, if necessary, using a crosslinking agent, various surfactants, and the like. Filler: binder 20: 1 to 1: 5, preferably 10: 1 to 1
Used in a 1: 1 weight ratio. In general, the filler is preferably an organic polystyrene resin, acrylic resin, polyolefin resin, benzoguanamine resin, melamine resin, urea-formalin resin, or the like having high heat insulation, and preferably has an average particle size of 0.4 to 2 μm.

In order to enhance the effect of the binder, it is preferable to use a crosslinking agent in combination. Examples of the crosslinking agent that can be used include glyoxal, formalin, borax, aziridine, dialdehyde starch, melamine resin, polyethyleneimine resin, polyamide / epichlorohydrin resin, ketone / aldehyde resin, epoxy resin, glycine, glycidyl ester, glycidyl ether, Ketene dimer, dimethylol urea, ammonium chloride, magnesium chloride, calcium chloride, aluminum sulfate, magnesium sulfate,
Examples include calcium hydroxide and zirconium ammonium carbonate.

The heat-sensitive recording material of the present invention is prepared by using the above-mentioned materials, for example, by the following method. That is, the filler and the binder and, if necessary, the crosslinking agent by a conventional method,
A wetting agent, an antifoaming agent, etc. are mixed and dispersed through water or an organic solvent such as toluene, IPA, etc. to prepare an intermediate layer coating solution.
It is applied on a support such as a plastic sheet or synthetic paper by a dry weight of 1 to 40 g / m ² , preferably 5 to 20 g / m ^{2 by a} bar coater, a brane coater or the like, and dried to form an intermediate layer. Next, the color-forming compound, 2,4'-dihydroxydiphenylsulfone, and 2- (2'-hydroxy-5'-methylphenyl) benzotriazole are separately ball milled together with a binder or other additives as necessary. After pulverized and dispersed by a disperser such as an attritor or a sand mill (when water is used for pulverization and dispersion, water is usually used as a medium), the mixture is mixed to prepare a thermosensitive coloring layer coating solution, Usually, the dry weight is 1
To 40 g / m ² by using the same coating method as that for forming the intermediate layer (the ratio of the color-forming compound to the color-developing compound is
Usually, the weight-to-weight ratio is 2: 1 to 1:10) and dried to form a heat-sensitive coloring layer to obtain the heat-sensitive recording material of the present invention. If necessary, an overcoat layer may be provided on the thermosensitive coloring layer.

According to the present invention, 2,4'-dihydroxydiphenylsulfone is used as a color-developing compound, and 2- (2'-hydroxy-5'-methylphenyl) benzotriazole and a synthetic paraffin wax are further contained in the thermosensitive coloring layer. The heat-sensitive recording material is superior in color development and less fogged, and has good storage stability such as plasticizer resistance and oil resistance as compared with conventionally known materials.

[0023]

EXAMPLES The present invention will be described in more detail with reference to Examples, but it should not be construed that the present invention is limited thereto. In the examples, "parts" indicates parts by weight.

Example 1 (Formation of Intermediate Layer) An intermediate layer coating solution having the following ratio was prepared and dried on a high-quality paper having a basis weight of 50 g / m ² and a weight of 8 when dried.
g / m ² and then applied and dried to form an intermediate layer. 166 parts of a 48% polystyrene fine particle dispersion liquid (average particle size: 0.5 μm) 40 parts of a 40% styrene / acrylate copolymer emulsion 50 parts of water 34 parts

(Formation of thermosensitive coloring layer) A mixture having the following composition was pulverized and dispersed using a sand grinder so that the average particle size became 2 μm or less, and [A] solution, [B] solution,
[C] The solution was prepared. [A] Solution: 3-dipentylamino-6-methyl-7-anilinofluorene 30 parts 25% PVA aqueous solution 20 parts Water 50 parts [B] Solution: 2,4'-dihydroxydiphenylsulfone 30 parts 25% PVA aqueous solution 20 Part water 50 parts [C] liquid: 2- (2'-hydroxy-5'-methylphenyl) benzotriazole 30 parts 25% PVA aqueous solution 20 parts water 50 parts

Next, the respective adjustment solutions are mixed at the following ratio to prepare a coating solution for the heat-sensitive coloring layer. The coating solution is coated on the above-mentioned intermediate layer so as to have a dry weight of about 7 g / m ² , dried and dried. A coloring layer is obtained. [A] solution 14 parts [B] solution 27 parts [C] solution 27 parts 30% synthetic paraffin wax dispersion (melting point 108 ° C) 11 parts 30% ethylene acrylic acid copolymer sodium salt 13 parts water 8 parts (protective layer Further, a coating solution for the protective layer having the following ratio is applied on the thermosensitive coloring layer so as to have a dry weight of 3 g / m ² and dried to obtain the thermosensitive recording material of the present invention. 15% carboxyl group-modified PVA aqueous solution 100 parts 20% colloidal silica dispersion 25 parts 30% glyoxal aqueous solution 1 part

[0027] Example 2 in place of the intermediate layer coating solution of Example 1, the intermediate layer coating solution was adjusted to a basis weight of 50 g / weight of dry the fine paper of m ² is 15 g / m ² composed of the following proportions Is applied and dried to form an intermediate layer, and then the heat-sensitive recording material of the present invention is obtained in the same manner as in Example 1. 30% polymethyl methacrylate fine particle dispersion (average particle diameter: 1 μm) 133 parts 40% styrene / acrylate copolymer emulsion 100 parts Water 17 parts

Example 3 In place of the solution [A] in Example 1, a 30% 3-dibutylamino-6-methyl-7-anilinofluorane dispersion, which was similarly ground and dispersed, was used. Similarly, the heat-sensitive recording material of the present invention is obtained.

Example 4 The heat-sensitive recording material of the present invention was prepared in the same manner as in Example 1 except that a 30% ethylene acrylic acid copolymer ammonium salt was used instead of the 30% ethylene acrylic acid copolymer sodium salt of Example 1. obtain.

Example 5 A heat-sensitive recording material of the present invention was obtained in the same manner as in Example 1 except that the coating solution of the thermosensitive coloring layer of Example 1 was used in place of the coating solution of the thermosensitive coloring layer of Example 1. [A] liquid 14 parts [B] liquid 27 parts [C] liquid 27 parts 30% synthetic paraffin wax dispersion (melting point 108 ° C) 11 parts 48% modified styrene / butadiene copolymer latex 8 parts water 13 parts

Comparative Example 1 A mixture [D] was prepared by pulverizing and dispersing a mixture having the following composition using a sand grinder so that the average particle diameter became 2 μm or less. [D] solution: 2- (2'-hydroxy-3 ', 5'-di-tert-butyl-phenyl) benzotriazole 30 parts 25% PVA aqueous solution 20 parts Water 50 parts Instead of the solution [C] of Example 1, Example 1 using solution [D]
In the same manner as in the above, a heat-sensitive recording material for comparison is obtained.

Comparative Example 2 A 30% polyethylene wax dispersion (melting point 110 ° C.) was used in place of the 30% synthetic paraffin wax dispersion (melting point 108 ° C.) of Example 1, and a heat-sensitive material for comparison was prepared in the same manner as in Example 1. Obtain the recording material.

Tables 1 and 2 show the quality performance of the heat-sensitive recording materials of the present invention and the comparative examples obtained as described above.

[0034]

[Table 1] Table 1. Quality performance test Ground 1) Color density 2) Color density 3) Heat resistance 4) Heat resistance 5) Example 1 0.04 1.70 1.41 0.12 0.30 Example 2 0.04 1.67 1 .39 0.15 0.35 Example 3 0.04 1.72 1.36 0.11 0.34 Example 4 0.04 1.69 1.42 0.18 0.38 Example 5 0.04 1.67 1.39 0.14 0.33 Comparative Example 1 0.04 1.70 0.98 0.15 0.32 Comparative Example 2 0.04 1.69 1.40 0.38 1.31

[0035]

[Table 2]

The methods of the quality performance tests listed in Tables 1 and 2 above are as follows. 1) Background: An uncolored sample was measured using a Macbeth reflection densitometer RD-9.
Value measured with type 14. 2) Coloring density: Macbeth reflection density of a printed portion of a sample printed using a commercially available POS label printer at normal printing energy. 3) Coloring density: Macbeth reflection density at the printing portion when printing was performed with the printing energy used at high speed of the printer. 4) Heat resistance: Macbeth reflection density of a sample formed by applying a hot plate at 100 ° C. for 1 ^{second at} a printing pressure of 1 kg / cm ² . 5) Heat resistance: Macbeth reflection density of a sample in which a hot plate at 110 ° C. was applied at a printing pressure of 1 kg / cm ² for 1 second to form a color. 6) Plasticizer resistance: The sample printed by the above printer was converted to PV
The afterimage ratio (%) of the density of the printed portion after leaving the C-wrap film on both sides at room temperature for 24 hours under a load of 300 g / cm ² . 7) Oil resistance: The residual image rate (%) of the density of the printed area after applying salad oil on a sample printed by the above printer and leaving it at room temperature for 24 hours.

As is clear from the table, the heat-sensitive recording material of the present invention has excellent coloring properties and heat resistance of the background against heat.
It has excellent storage stability such as plasticizer resistance and oil resistance in the colored portion.

[0038]

EFFECT OF THE INVENTION As a color developing compound, 2
A heat-sensitive recording material containing 4'-dihydroxydiphenyl sulfone as a heat-fusible compound, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, and a synthetic paraffin wax in a heat-sensitive coloring layer has a high coloring property. It is excellent, has little background covering on heat, and has excellent preservability such as plasticizer resistance and oil resistance in the color-developed portion.

Claims (3)

[Claims] 1. A thermosensitive recording material comprising a support having thereon a colorless or light-colored color-forming compound and a heat-sensitive color-forming layer mainly composed of a color-developing compound capable of coloring the color-forming compound when heated. 2,4'-dihydroxydiphenylsulfone as a heat-soluble compound, and 2- (2'-hydroxy-5'-methylphenyl) benzotriazole and a synthetic paraffin wax as a heat-fusible compound in a thermosensitive coloring layer. Heat-sensitive recording material. 2. A synthetic paraffin wax having a melting point of 100 to 100.
The heat-sensitive recording material according to claim 1, wherein the temperature is 130 ° C. 3. The heat-sensitive recording material according to claim 1, wherein an intermediate layer is provided between the heat-sensitive coloring layer and the support.