JP3121359B2 - Thermal recording material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording material, and more particularly, to a heat-sensitive recording material having improved properties by providing an elastic layer between a support and a heat-sensitive coloring layer.

[0002]

2. Description of the Related Art Recently, various recording materials have been researched, developed, and put to practical use in the information recording field in accordance with social demands such as diversification and increase of information, resource saving, and non-pollution. Above all, the heat-sensitive recording material is (1) a color image is recorded simply by heating, and a complicated developing step is not required; (2) a relatively simple and compact apparatus can be used for recording ; The obtained recording material is easy to handle and the maintenance cost is low. (3) In many cases, paper is used as a support. In this case, not only the support cost is low but also the obtained material is obtained. Because of the advantages such as the feel of the recording material being close to that of plain paper, the fields of computer output, printers such as calculators, recorders for medical measurement, low and high-speed facsimile, automatic ticket vending machines, thermal copying, POS Widely used in the stem of the label field and the like.

The above-mentioned thermosensitive recording material is usually produced by applying and drying a thermosensitive coloring layer solution containing a coloring component capable of causing a coloring reaction by heating on a support such as paper, synthetic paper or synthetic resin film. The heat-sensitive recording material thus obtained is heated by a hot pen or a thermal head to record a color image. Conventional examples of such a heat-sensitive recording material include, for example, Japanese Patent Publication No. 43-4160.
Or the heat-sensitive recording material disclosed in JP-B-45-14039. However, such a conventional heat-sensitive recording material has, for example, a low thermal response, and does not provide a sufficient color density during high-speed recording. . As a method for remedying such a defect, for example, Japanese Patent Application Laid-Open No. S49-38424 discloses the use of a nitrogen-containing compound such as acetamide, stearamide, m-nitroaniline, dinitrile phthalate, etc.
No. 06746 discloses an acetoacetic anilide disclosed in
JP-A-3-11036 discloses N, N-diphenylamine derivatives, benzamide derivatives and carbazole derivatives, and JP-A-53-39139 discloses alkylated biphenyls and biphenylalkanes and JP-A-56-144193.
In the publication, a p-hydroxybenzoic acid ester derivative,
Methods for increasing the speed and increasing the sensitivity by adding each of them are disclosed, but at present, no satisfactory results have been obtained by any of the methods. As another method, Japanese Patent Application Laid-Open No. 56-164890 discloses a method in which a leuco dye having a high melting point is made amorphous to lower the melting point and increase the sensitivity. However, since the surface of the amorphized dye is activated and has high reactivity, there is a problem that the fogging or background fog of the thermosensitive coloring liquid or the thermosensitive recording material is large and the whiteness is poor.

Therefore, in order to suppress background fog and enhance dynamic color development sensitivity, the thermal conductivity of the support is set to 0.04 Kca.
1 / mh ° C. or lower (Japanese Patent Laid-Open No. 55-164192) or providing a layer mainly composed of fine hollow sphere particles on a support (Japanese Patent Laid-Open Nos. 59-5093 and 59-225).
No. 987) and a method using non-foamable fine hollow particles of 5 μm or less made of a thermoplastic resin for the intermediate layer (Japanese Patent Application Laid-Open No. 62-5886).
Has been proposed.

[0005]

However, the heat-sensitive recording materials proposed in the above-mentioned JP-A-55-164192 and JP-A-59-5093 have insufficient foaming properties and are not suitable for wall materials. In some cases, the thermal head may not have sufficient heat insulating properties, or the thermal head may have insufficient adhesion to the heat-sensitive recording material. The thermal recording material proposed in Japanese Patent Application Laid-Open No. Sho 62-5886 does not produce satisfactory results.

Accordingly, an object of the present invention is to provide a thermosensitive recording material which is excellent in dot reproducibility and can obtain a clear recorded image.

[0007]

According to the present invention, an elastic layer and a thermosensitive coloring layer mainly composed of a leuco dye and a developer which causes the leuco dye to develop color when heated are successively laminated on a support. A heat-sensitive recording material comprising:
A heat-sensitive recording material having a hardness of 90 or less as measured by a C-type hardness meter according to IS K6301 is provided.

That is, in the present invention, an elastic layer is provided between the support and the heat-sensitive coloring layer, and the heat-sensitive recording material is JIS K6301.
, The adhesion between the thermal head and the thermosensitive recording material is improved, and a clear recorded image with good dot reproducibility can be obtained. .

When an elastic layer is provided between the support and the thermosensitive coloring layer to obtain a thermosensitive recording material capable of obtaining a high-density recorded image with a small amount of energy, the thermal sensitivity of the thermosensitive recording material is affected. One of the factors is the adhesion between the thermal head and the thermal recording material. However, there is a correlation between the adhesiveness and the elasticity (in other words, hardness) of the heat-sensitive recording material. When the hardness is less than a certain value, the adhesiveness with the thermal head becomes good, and as a result, the heat-sensitive recording material Has good thermal sensitivity and dot reproducibility. The heat-sensitive recording material of the present invention,
Hardness of 90 with a C-type hardness meter according to JIS K 6301
The following is shown. When the hardness is more than 90, the adhesiveness of the head is reduced, and the dot reproducibility, the thermal sensitivity and the like are deteriorated.

As a method for improving the elasticity of the thermosensitive recording material, it is conceivable to improve the elasticity with a support, a thermosensitive coloring layer, an overcoat layer, or the like, but each has a main function and impairs this function. It is extremely difficult to improve the elasticity without using the same. Therefore, in the present invention, an elastic layer is provided between the support and the heat-sensitive coloring layer.To improve the elasticity of the heat-sensitive recording material, many holes are provided in the elastic layer, and when this space is pressurized. It is important that the material deforms into a non-pressurized shape and recovers under non-pressure.

[0011] As one of the methods for forming the elastic layer of the present invention,
There is a method of forming an elastic layer having improved elasticity by containing ² g / m ² or more of resin particles having a hollowness of 80% or more. In addition,
Here, the hollowness is a ratio of the outer diameter to the inner diameter of the hollow particles, and is expressed by the following formula.

The hollow resin particles used in the present invention have a resin shell and contain air or other gas inside.
Hollow particles that are already in a foamed state and have a hollowness of 8
If it is less than 0%, the elasticity cannot be improved within the practical hollow particle adhesion amount (about 30 g / m ² ) even if the content is ² g / m ² or more. On the other hand, if the amount of the hollow particles attached to the elastic layer is less than 2 g / m ² , the elasticity of the thermosensitive recording material cannot be improved.

As another method of forming the elastic layer, a porous silica having a bulk density of 0.15 g / cc or less is prepared at 15 g / m ^2.
There is a method of forming an elastic layer having the above-mentioned content and having improved elasticity. The bulk density referred to here is JIS K510
It is a value measured based on 1.

The porous silica used in the present invention is a silica having pores on its surface and has a bulk density of 0.15 g / c.
If it exceeds c, the elasticity cannot be improved within the practical pigment adhesion amount (about 30 g / m ² ) even if it is contained in an amount of 15 g / m ² or more. On the other hand, when the amount of the porous silica adhered to the elastic layer is less than 15 g / m ² , the elasticity of the thermosensitive recording material cannot be improved.

Although the two methods of forming the elastic layer have been described above, the method is not limited to the two methods as long as the elastic layer is improved in its elasticity by forming many voids.

In order to provide the elastic layer on a support, the resin hollow particles or porous silica are dispersed in water together with a known binder such as a water-soluble polymer or an aqueous polymer emulsion. It is obtained by applying to a surface and drying.

In the present invention, the binder used for forming the elastic 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 ethylcellulose, sodium polyacrylate,
Polyvinylpyrrolidone, acrylamide / acrylate copolymer, acrylamide / acrylate /
Examples include methacrylic acid terpolymer, alkali salt of styrene / maleic anhydride copolymer, alkali salt of isobutylene / maleic anhydride copolymer, polyacrylamide, sodium alginate, gelatin, casein and the like. Examples of the aqueous polymer emulsion include latexes such as styrene / butadiene copolymer, styrene / butadiene / acrylic copolymer, vinyl acetate resin, vinyl acetate / acrylic acid copolymer, and styrene / acrylic acid ester copolymer. And emulsions of acrylate resin, polyurethane resin and the like.

In the elastic layer of the present invention, together with the resin hollow particles or the porous silica and the binder,
If necessary, auxiliary additives commonly used in this type of heat-sensitive recording material, for example, fillers, heat-fusible substances, surfactants and the like can be used in combination. In this case, specific examples of the filler and the heat-fusible substance include various substances described below in relation to the thermosensitive coloring layer component.

Further, in order to smooth the surface of the elastic layer formed on the support as described above, the flat surface may be smoothed by calendering after forming the elastic layer.

The leuco dye used in the thermosensitive coloring layer of the present invention may be used alone or as a mixture of two or more kinds. As such a leuco dye, those applied to this kind of thermosensitive material may be arbitrarily applied. For example, leuco compounds of dyes such as triphenylmethane type, fluoran type, phenothiazine type, auramine type, spiropyran type and indolinophthalide type are preferably used. Specific examples of such leuco dyes include, for example, those shown below.

3,3-bis (p-dimethylaminophenyl) -phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (also known as crystal violet lactone), 3,3-bis ( (p-dimethylaminophenyl) -6-diethylaminophthalide,
3,3-bis (p-dimethylaminophenyl) -6-chlorophthalide, 3,3-bis (p-dibutylaminophenyl) phthalide, 3-cyclohexylamino-6-chlorofluoran, 3-dimethylamino-5,7 -Dimethylfluoran, 3-diethylamino-7-chlorofluoran, 3-diethylamino-7-methylfluoran, 3-
Diethylamino-7,8-benzfluoran, 3-diethylamino-6-methyl-7-chlorofluoran, 3-
(Np-tolyl-N-ethylamino) -6-methyl-
7-anilinofluoran, 3-pyrrolidino-6-methyl-7-anilinofluoran, 2- {N- (3'-trifluoromethylphenyl) amino} -6-diethylaminofluoran, 2- {3 6-bis (diethylamino)-
Lactam 9- (o-chloroanilino) xanthylbenzoate, 3-diethylamino-6-methyl-7- (m-trichloromethylanilino) fluoran, 3-diethylamino-7- (o-chloroanilino) fluoran, 3-di- n-butylamino-7- (o-chloroanilino) fluoran, 3-N-methyl-N, n-amylamino-6-
Methyl-7-anilinofluoran, 3-N-methyl-N
-Cyclohexylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-anilinofluoran, 3- (N, N-diethylamino) -5
-Methyl-7- (N, N-dibenzylamino) fluoran, benzoylleucomethylene blue, 6'-chloro-
8'-methoxy-benzoindolino-spiropyran, 6 '
-Bromo-3'-methoxy-benzoindolino-spiropyran, 3- (2'-hydroxy-4'-dimethylaminophenyl) -3- (2'-methoxy-5'-chlorophenyl) phthalide, 3- (2 '-Hydroxy-4'-dimethylaminophenyl) -3- (2'-methoxy-5'-nitrophenyl) phthalide, 3- (2'-hydroxy-4'-diethylaminophenyl) -3- (2'-methoxy -5'-
Methylphenyl) phthalide, 3- (2′-methoxy-4 ′)
-Dimethylaminophenyl) -3- (2'-hydroxy-4'-chloro-5'-methylphenyl) phthalide, 3-
(N-ethyl-N-tetrahydrofurfuryl) amino-
6-methyl-7-anilinofluoran, 3-N-ethyl-N- (2-ethoxypropyl) amino-6-methyl-
7-anilinofluoran, 3-N-methyl-N-isobutyl-6-methyl-7-anilinofluoran 3-morpholino-7- (N-propyl-trifluoromethylanilino) fluoran, 3-pyrrolidino- 7-m-trifluoromethylanilinofluoran, 3-diethylamino-5
-Chloro-7- (N-benzyl-trifluoromethylanilino) fluoran, 3-pyrrolidino-7- (di-p-
(Chlorophenyl) methylaminofluoran, 3-diethylamino-5-chloro-7- (α-phenylethylamino) fluoran, 3- (N-ethyl-p-toluidino)
-7- (α-phenylethylamino) fluoran, 3-
Diethylamino-7- (o-methoxycarbonylphenylamino) fluoran, 3-diethylamino-5-methyl-7- (α-phenylethylamino) fluoran, 3
-Diethylamino-7-piperidinofluoran, 2-chloro-3- (N-methyltoluidino) -7- (pn-
Butylanilino) fluoran, 3- (N-methyl-N-
Isopropylamino) -6-methyl-7-anilinofluoran, 3-di-n-butylamino-6-methyl-7-
Anilinofluoran, 3,6-bis (dimethylamino)
Fluorene spiro (9,3 ')-6'-dimethylaminophthalide, 3- (N-benzyl-N-cyclohexylamino) -5,6-benzo-7-α-naphthylamino-4'
-Bromofluorane, 3-diethylamino-6-chloro-7-anilinofluoran, 3-diethylamino-6
Methyl-7-mesitidino-4 ′, 5′-benzofluoran, 3-N-methyl-N-isopropyl-6-methyl-
7-anilinofluoran, 3-N-ethyl-N-isoamyl-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7- (2 ′, 4′-dimethylanilino) fluoran etc.

As the color developer used in the thermosensitive coloring layer of the present invention, various compounds having an electron-accepting property, or an oxidizing agent, for coloring the leuco dye upon contact are applied. Such materials are conventionally known, and specific examples thereof include the following.

4,4'-isopropylidene diphenol, 4,4'-isopropylidenebis (o-methylphenol), 4,4'-secondarybutylidenebisphenol 4,4'-isopropylidenebis (2-tertiary) Butylphenol), zinc p-nitrobenzoate,
1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid, 2,2- (3,4′-dihydroxydiphenyl) propane, bis (4-hydroxy-3 -Methylphenyl) sulfide, 4- {β- (p-methoxyphenoxy) ethoxy} salicylic acid, 1,7-bis (4-hydroxyphenylthio) -3,5-dioxaheptane, 1,5-bis (4- (Hydroxyphenylthio) -5-oxapentane, monobenzyl phthalate monocalcium salt,
4,4'-cyclohexylidenediphenol, 4,4 '
-Isopropylidenebis (2-chlorophenol),
2,2'-methylenebis (4-methyl-6-tert-butylphenol), 4,4'-butylidenebis (6-
Tert-butyl-2-methyl) phenol, 1,
1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,1,3-tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) butane, 4,4 ′ -Thiobis (6-tert-butyl-2-methyl) phenol, 4,4'-diphenolsulfone, 4-isopropoxy-4'-hydroxydiphenylsulfone, 4-benzyloxy-4'-hydroxydiphenylsulfone, 4,4 '-Diphenol sulfoxide, isopropyl P-hydroxybenzoate,
Benzyl P-hydroxybenzoate, benzyl protocatechuylate, stearyl gallate, lauryl gallate, octyl gallate, 1,3-bis (4-hydroxyphenylthio) -propane, N, N′-diphenylthiourea,
N, N'-di (m-chlorophenyl) thiourea, salicylanilide, methyl bis- (4-hydroxyphenyl) acetate, benzyl bis- (4-hydroxyphenyl) acetate, 1,3-bis (4-hydroxycumyl) )benzene,
1,4-bis (4-hydroxycumyl) benzene, 2,
4'-diphenol sulfone, 2,2'-diallyl-4,
4'-diphenolsulfone, 3,4-dihydroxyphenyl-4'-methyldiphenylsulfone, zinc 1-acetyloxy-2-naphthoate, 2-acetyloxy-
Zinc 1-naphthoate, zinc 2-acetyloxy-3-naphthoate, α, α-bis (4-hydroxyphenyl)-
α-methyltoluene, antipyrine complex of zinc thiocyanate, tetrabromobisphenol A, tetrabromobisphenol S, 4,4′-thiobis (2-methylphenol), 4,4′-thiobis (2-chlorophenol) and the like.

In the heat-sensitive coloring layer of the present invention, various conventional binders can be appropriately used for applying the leuco dye and the color developing agent on the elastic layer. And the same as those exemplified in the application of the elastic layer.

Further, in the thermosensitive coloring layer of the present invention, if necessary, together with the leuco dye and the developer,
Auxiliary additives commonly used in this type of heat-sensitive recording material, for example, fillers, heat-fusible substances, surfactants and the like can be used in combination. In this case, as the filler, for example,
Calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay,
In addition to inorganic fine powders such as talc and surface-treated calcium and silica, organic fine powders such as urea-formalin resin, styrene / methacrylic acid copolymer, and polystyrene resin can be used. Examples of the active substance include higher fatty acids or esters, amides or metal salts thereof, various waxes, condensates of aromatic carboxylic acids and amines, phenyl benzoate, higher linear glycols, 3,4- 50 of dialkyl epoxy-dialkyl hexahydrophthalate, higher ketones and other heat-fusible organic compounds
Those having a melting point of about 200 ° C. are mentioned.

In the present invention, a layer containing a filler, a binder, a heat-fusible substance or the like may be provided as an intermediate layer between the elastic layer and the thermosensitive coloring layer, if necessary. In this case, specific examples of the filler, the binder, and the heat-fusible substance include those similar to those exemplified in relation to the thermosensitive coloring layer or the elastic layer.

Further, in the heat-sensitive recording material of the present invention, it is possible to provide a protective layer on the heat-sensitive coloring layer for the purpose of improving the matching property of a thermal head or the like and further improving the preservability of a recorded image. In this case, the above-mentioned filler, binder, surfactant, and heat-fusible substance can also be used as components constituting the protective layer.

The heat-sensitive recording material of the present invention is produced, for example, by applying the above-mentioned coating liquid for forming each layer on a suitable support such as paper, synthetic paper, plastic film and the like, followed by drying. Applied in the recording field.

[0029]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The parts and percentages shown below are based on weight.

Example 1 [Solution A] 20 parts of 3-di-n-butylamino-6-methyl-7-anilino 20 parts of a 10% aqueous solution of polyvinyl alcohol 20 parts of water

[Solution B] 1,5-bis (4-hydroxyphenylthio) -3-10 parts Oxapentane 10% aqueous solution of polyvinyl alcohol 25 parts Calcium carbonate 15 parts Water 50 parts

The mixture composed of the above compositions was dispersed using a sand mill so that the average particle diameter was 2.5 μm or less, to thereby prepare [Solution A] and [Solution B].

[Liquid C] Plastic spherical hollow particle dispersion (solid content: 32%) 50 parts (average particle diameter: 5 μm, hollowness: 92%) Styrene / butadiene copolymer latex (solid content: 47.5%) 5 parts Water 50 Department

An elastic layer forming solution was prepared by stirring and dispersing the mixture having the above-mentioned composition, and this was mixed with a commercially available high-quality paper (with a basis weight of 52 g).
/ M ² ), dried and then applied to a weight of 5 g / m ² after drying, and dried at 50 ° C. for 1 minute to obtain an elastic layer coated paper.

Next, the above [Solution A] and [Solution B] were mixed and stirred at a weight ratio of 1:10 to prepare a thermosensitive coloring layer forming solution, and this was coated on the surface of the above-mentioned elastic layer coated paper. And dried at 50 ° C. for 1 minute to form a thermosensitive coloring layer, and then a Beck smoothness of 50 g / m ² was applied.
The heat-sensitive recording material of the present invention was obtained by a calendering treatment for 0 to 1,000 seconds.

Example 2 A heat-sensitive recording material of the present invention was obtained in the same manner as in Example 1, except that after forming the elastic layer-coated paper in Example 1, the paper was heated at 140 ° C. for 1 minute.

Example 3 In place of the plastic spherical hollow particle dispersion in [Liquid C] of Example 1, a porous silica dispersion (solid content: 3%) was used.
2%, bulk specific gravity 0.143g / cc, average particle size 1.5μ
m, an oil absorption of 150 ml / 100 g), and stirred and dispersed in the same manner as in Example 1 to prepare a coating solution for the elastic layer, and after drying on a surface of a commercial high-quality paper (basis weight: 52 g / m ² ), the weight was 20 g / m ^2.
m ² was applied and dried to obtain an elastic layer-coated paper.

Further, after providing a thermosensitive coloring layer on the elastic layer coated paper in the same manner as in Example 1, the Bekk smoothness was 500 to
A calendering treatment was performed for 1,000 seconds to obtain a heat-sensitive recording material of the present invention.

Example 4 After forming the elastic layer coated paper in Example 3, the Beck smoothness was 5
A heat-sensitive recording material of the present invention was obtained in the same manner as in Example 3, except that the calendering treatment was performed so that the time became 00 to 1,000 seconds.

Comparative Example 1 Plastic spherical hollow particles (Mitsui Toatsu Co., Ltd .: SPMM-HS, solid concentration 32%) were used in place of the plastic spherical hollow particle dispersion in [Liquid C] of Example 1. Except for the above, a thermal recording material for comparison was obtained in the same manner as in Example 1.

Comparative Example 2 A heat-sensitive recording material for comparison was obtained in the same manner as in Example 1 except that after forming the elastic layer-coated paper in Example 1, the paper was heated at 140 ° C. for 5 minutes.

Comparative Example 3 A comparative example was prepared in the same manner as in Example 3 except that after forming the elastic layer-coated paper in Example 3, the paper was subjected to a calendering treatment so that the Bekk smoothness became 1,000 to 2,000 seconds. A heat-sensitive recording material was obtained.

Comparative Example 4 In place of the plastic spherical hollow particle dispersion in [Liquid C] of Example 1, a plastic spherical hollow particle dispersion (solid content: 32%, average particle diameter: 0.4 μm, hollowness: 7%)
5%) to obtain a comparative thermosensitive recording material in the same manner as in Example 1.

Comparative Example 5 Instead of the porous silica dispersion in [C solution] of Example 3, a porous silica dispersion (solid content: 32%, bulk specific gravity: 0.1%) was used.
155 g / cc, average particle size 2.7 μm, oil absorption 135
(ml / 100 g) to obtain a comparative thermosensitive recording material in the same manner as in Example 3.

Each of the heat-sensitive recording materials obtained as described above was tested for dynamic color sensitivity and dot reproducibility. The test was performed as follows. Using a thermal printing tester with a thin-film head manufactured by Matsushita Electronic Components Co., Ltd., head power 0.45 w / dot, line recording time 20 msec / l, scanning line density 8 × 3.85 dots / m
Under m conditions, pulse widths of 0.3, 0.4, 0.5 and 0.
6msec and print density is measured by Macbeth densitometer R
It was measured by D-914. Table 1 shows the results. Also,
At the same time, the image was visually evaluated for dot reproducibility. The evaluation results are shown in Table 2 together with the hardness measurement results of the thermosensitive recording material using a C-type hardness meter according to JIS K6301.

[0046]

[Table 1]

[0047]

[Table 2]

From the results of Tables 1 and 2, it can be seen that the thermosensitive recording material of the present invention has excellent dot reproducibility and a clearer image than the thermosensitive recording material of Comparative Example.

[0049]

According to the heat-sensitive recording material of the present invention, an elastic layer is provided between the support and the heat-sensitive coloring layer, and the JIS of the heat-sensitive recording material is provided.
Since the hardness of the C-type hardness meter according to K6301 is 90 or less, the adhesion to the thermal head during printing is improved, and the dot reproducibility is excellent.
In addition, a clear recorded image can be obtained.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akie Murofushi 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (56) References JP-A-63-299975 (JP, A) JP-A Sho 64-82983 (JP, A) JP-A-1-285383 (JP, A) JP-A-2-116591 (JP, A)

Claims (3)

(57) [Claims] 1. A thermosensitive recording material comprising a support and an elastic layer, and a thermosensitive coloring layer mainly composed of a leuco dye and a developer which causes the leuco dye to develop a color when heated. A heat-sensitive recording material, wherein the material has a hardness of 90 or less as measured by a C-type hardness meter according to JIS K6301. 2. The heat-sensitive recording material according to claim 1, wherein the elastic layer contains ² g / m ² or more of hollow resin particles having a hollowness of 80% or more. 3. The heat-sensitive recording material according to claim 1, wherein the elastic layer contains 15 g / m ² or more of porous silica having a bulk density of 0.15 g / cc or less.