JPH04201481A - heat sensitive recording material - Google Patents

Abstract

PURPOSE:To obtain a thermal recording material having high thermal response and recording density for higher sensibility, in which adhesion of print chips is suppressed, by forming an intermediate layer mainly comprising a capsule including air, a pigment having specified oil absorption and adhesives between a supporter and a thermal recording layer. CONSTITUTION:An intermediate layer mainly comprising capsules including air, a pigment having oil absorption of 80ml/100g or more and adhesives is formed between a supporter and a thermal recording layer. The mean capsule outside diameters of the air capsules extend over 20mum from 2mum. A pigment having oil absorption of 80ml/100g or more such as kaolin, calcined kaolin, calcium carbonate, magnesium carbonate, calcium oxide, magnesium oxide, a cellulose filler, etc., is selected arbitrarily and used as the pigment employed for the intermediate layer. Normally used various adhesives can be employed arbitrarily as adhesives used for the intermediate layer.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a thermal recording material that has excellent thermal responsiveness, high recording density, and less adhesion of printing residue to a thermal head.

[Conventional technology]

A heat-sensitive recording material, which has a heat-sensitive recording layer mainly composed of a reactant and co-reactant that causes a color-forming reaction when heated, is formed on a support by heating it with a heat head, a thermal pen, a laser beam, etc. It is possible to obtain recorded images. In addition, because records can be obtained using relatively simple equipment, it is easy to maintain, and it does not generate noise. It is used in a wide range of fields such as Particularly in the field of facsimile, demand for heat-sensitive methods has increased significantly, and they have become the mainstream recording method. Furthermore, with the spread of facsimiles, facsimile machines are becoming less expensive, energy efficient, and smaller.
Quality requirements for heat-sensitive recording materials are also becoming stricter. That is, there is a demand for high sensitivity and stable printing corresponding to the lower energy consumption of facsimile machines, in other words, it is required to develop colors with sufficient density even with small thermal energy, and to reduce the adhesion of printing scum to the thermal head. In order to meet these demands, we have developed the idea of effectively utilizing thermal energy and increasing sensitivity by providing an insulating effect to the intermediate layer, and we have developed microscopic hollow particles that expand thermally or foaming agents that generate gas when heated. Method of providing an intermediate layer mainly composed of a thermoplastic polymer (Japanese Patent Application Laid-Open No. 51-509
3, JP-A-59-171685, etc.) or a method using micro hollow particles (JP-A-60-248390, etc.)
Publications, etc.) have been proposed. However, the former method requires an inefficient heating and foaming process;
Furthermore, it is difficult to uniformly foam the foam, making it difficult to achieve uniform surface properties. As a result, a drawback arises in that the print quality lacks stability, and it is not possible to achieve both high sensitivity due to heat insulation and print quality. Also,
In the latter case, the porosity of micro hollow particles is low, and it is difficult to manufacture large particles that can have sufficient heat insulation properties, so they do not have sufficient heat insulation effects and cannot provide satisfactory thermal response. The current situation is that it is not. In addition, obtaining sufficient color density with a small amount of thermal energy by providing a heat insulating effect to the intermediate layer means increasing the melting amount of the coloring component with respect to the applied thermal energy, which reduces printing scum on the thermal head. When printing is performed for a long time, printing scum adhering to the thermal head may cause printing problems. Therefore, in response to the demands for high sensitivity and stable printing, it is desired to solve the contradictory problems of increasing the color density by increasing the melting amount of the coloring component and suppressing the generation of printing scum. is the current situation.

[Problem to be solved by the invention]

The present invention addresses the need for higher sensitivity, which could not be achieved with conventional techniques, and has high thermal responsiveness and recording density.
Furthermore, it is an object of the present invention to provide a heat-sensitive recording material with a small amount of adhesion of printing residue.

[Means to solve the problem]

In order to meet the demands for higher sensitivity and stable printing of heat-sensitive recording materials, the present inventors have proposed increasing the amount of heat supplied from the thermal head and increasing the amount of heat supplied from the thermal head by adding flexibility and heat insulation to the intermediate layer. In addition to preventing heat from escaping into the material, the molten coloring component quickly moves to the intermediate layer and away from the thermal head, suppressing the adhesion of printing scum, resulting in high sensitivity and stable printing. After thinking about the possibility of printing, and as a result of intensive study, we found that a capsule containing air between the support and the heat-sensitive recording layer and an oil absorption amount of 80 ml/'1. It has been found that high sensitivity and stable printing can be achieved by providing an intermediate layer mainly composed of a pigment and an adhesive having an OOg or more, and the present invention has been completed. The air-encapsulating capsule used in the present invention, that is, the air capsule, can be manufactured by using an encapsulation method known in the art. For example, U.S. Patent No. 2,800,457
The phase separation method from an aqueous solution as shown in Japanese Patent Publication No. 38-19574, Japanese Patent Publication No. 42-446, Japanese Patent Publication No. 42-771, etc. Legal, Special Publication No. 36-9168, Japanese Patent Publication No. 5
1n-situ method by polymerization of monomers as shown in Publication No. 1-9079, etc., British Patent No. 952807,
The melting and dispersion cooling method shown in the specification of the same No. 965074, etc., U.S. Patent No. 3111407, British Patent No. 93042
Although there are spray lying methods shown in Specification No. 2 and the like, the 1n-situ method is preferably used. One example of a method for manufacturing air capsules is to prepare a solution containing air bubbles of any size in advance, and then form a wall film around the air bubbles. Furthermore, it is possible to form a wall membrane after performing multi-step emulsification such as further emulsifying a solution containing air bubbles, but the capsule manufacturing method is not limited to these methods. As the wall film forming material, ceratin, gum arabic, starch, sodium alginate, ethyl cellulose, carboxyethyl cellulose, polyvinyl alcohol, polyethylene, polyamide, polyester, polyurethane, polyethyleneimine, melamine-formalin, etc. can be used. Since the air capsule according to the present invention has an arbitrary size and a very narrow particle outer diameter distribution, it is possible to adjust the amount of air introduced into the intermediate layer by adjusting the amount of the capsule. Additionally, the amount of air inside the capsule can be adjusted depending on the required insulation effect. That is, it is possible to produce air capsules with arbitrary particle outer diameters and wall thicknesses. Furthermore, since the content is air, it can be used without any environmental problems. The average capsule outer diameter of the air capsule used in the present invention is 2 μm or more and 20 μm or less, preferably 3 μm.
15 μm or more, more preferably 4 μm or more and 10 μm
m or less. If the average outer diameter of the air capsule is smaller than 2 μm, not only will the insulation effect not be achieved, but also the gaps between the particles will become too small and the molten material of the coloring component will migrate to the intermediate layer during printing. This may become a hindrance and cause an increase in the adhesion of printing residue to the thermal head. Also, 20
If it is larger than μm, even if calender treatment is performed after coating the heat-sensitive recording layer, it will not be sufficiently smoothed, high sensitivity will not be achieved, and printing quality will also deteriorate. Pigments used in the intermediate layer of the present invention include, for example, kaolin, calcined kaolin, calcium carbonate, magnesium carbonate, calcium oxide, magnesium oxide, titanium oxide, zinc oxide, natural silica, synthetic silica, aluminum hydroxide, urea-formalin. Oil absorption from pigments such as fillers and cellulose fillers is 80 m, 1/'100
g or more can be arbitrarily selected and used, and it is also possible to use two or more types in combination. If the oil absorption amount of the pigment is less than 80 ml/100 g, the melt of the coloring component will not move sufficiently to the intermediate layer during printing, resulting in increased adhesion of printing scum to the thermal head. The amount of air capsules added in the present invention is preferably 1 part to 100 parts, more preferably 20 parts to 50 parts, based on 100 parts of the pigment. If the amount of air capsules added is less than 1 part, a sufficient heat insulating effect cannot be obtained, and if it exceeds 100 parts, a sufficient absorption effect by the pigment cannot be obtained. As the adhesive used in the intermediate layer of the present invention, any of various commonly used adhesives can be used. For example, starches, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, gelatin, casein, polyvinyl alcohol, modified polyvinyl alcohol, polyacrylic acid sorter, acrylamide/'acrylic acid ester copolymer, acrylamide/'
Water-soluble adhesives such as acrylic acid ester/methacrylic acid ternary copolymer, alkali salt of styrene/maleic anhydride copolymer, alkali salt of ethylene/'maleic anhydride copolymer, polyvinyl acetate, polyurethane, Latexes such as polyacrylic acid ester, styrene/butadiene copolymer, acrylonitrile/butadiene copolymer, methyl acrylate/butadiene copolymer, ethylene/vinyl acetate copolymer, and the like can be mentioned. It is possible to further add various additives to the intermediate layer, such as surfactants, thermoplastics, etc. The heat-sensitive recording material used in the heat-sensitive recording layer of the present invention includes:
Any combination of reactants and co-reactants that causes a color-forming reaction when two or more components come into contact with each other due to heat is sufficient. For example, a combination of an electron-donating colorless dye precursor and an electron-accepting compound, or a combination of an imino compound and an electron-donating colorless dye precursor is sufficient. Examples include combinations with aromatic isocyanate compounds and combinations of higher fatty acid metal salts such as ferric stearate and phenols such as gallic acid. Further, any material used in heat-sensitive recording materials, such as heat-sensitive recording materials in which a diazonium compound, a coupler, and a basic substance are combined, can be used without particular limitation. Specific examples of heat-sensitive recording materials in which an electron-donating colorless dye precursor and an electron-accepting compound are combined for use in the heat-sensitive recording layer of the present invention are shown below. Specific examples of electron-donating colorless dye precursors include (1) triarylmethane compound 3.3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalite (crystal violet lactone); 3.3-bis(p-dimethylaminophenyl)phthalide, 3-(p-dimethylaminophenyl)-3-(1,2-
Dimethylindol-3-yl)phthalide, 3-(p-dimethylaminophenyl)-3-(2-methylindol-3-yl)phthalide, 3-(p-dimethylaminophenyl)-3-(2-phenylindole) −
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-bis(2-phenylindole-
3-yl)-5-dimethylaminophthalide, 3-p-dimethylaminophenyl-3-(t-methylpyrrole-2
-yl)-6-dimethylaminophthalide and the like. (2) Diphenylmethane compounds 4.4'-bis-dimethylaminophenylbenzhydrylbenzyl ether, N-2,4,5-4-lichlorophenyl leukoolamine, etc. (3) Xanthine compounds Rhodamine B anilinolactam, Rhodamine B-p-chloroanilinolactam, 3-diethylamino-7-dibenzylaminofluoran, 3-diethylamino-7-octylaminofluorane, 3-diethylamino-7 -Phenylfluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-6-chloro-7-methylfluorane, 3-diethylamino-7-(3,4-dichloroanilino)fluorane, 3-diethylamino- 7-(2-chloroanilino)fluoran, 3-diethylamino-6-methyl-7-anilinofluoran, 3-(N-ethyl-N-tolyl)amino-6-methyl-
7-anilinofluorane, 3-piperidino-6-methyl-7-anilinofluorane, 3-(N-ethyl-N-tolyl)amino-6-methyl-
7-phenethylfluorane, 3-diethylamino-7-(4-nitroanilinofluorane, 3-dibutylamino-6-methyl-7-anilinofluorane, 3-(N-methyl-N-propyl)amino- 6-Methyl-7-anilinofluorane, 3-(N-ethyl-N-isoamyl)amino-6-methyl-7-anilinofluorane, 3-(N-methyl-N-
cyclohexyl)amino-6-methyl-7-anilitofluorane, 3-(N-ethyl-N-tetrahydrofuryl)amino-6-methyl-7-anilinofluorane, and the like. (4) Thiazine compounds benzoylleucomethylene blue, p-nitrobenzoylleucomethylene blue, etc. (5) Spiro-based compounds 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3.3゛-dichlorospirodinaphthopyran, 3-benzylspirodinaphthopyran, 3-methylnaphtho-(3-methoxybenzo ) spiropyran, 3-propylspilobenzopyran, etc., and these can be used alone or in a mixture of two or more. Examples of electron-accepting compounds include phenol derivatives, aromatic carboxylic acid derivatives or their metal compounds, N,
N'-diarylthiourea derivatives and the like are used. Among these, particularly preferred are phenol derivatives, specifically p-phenylphenol, p-hydroxyacetophenone, 4-hydroxy-4°-methyldiphenylsulfone, 4-hydroxy-4°-isopropoxydiphenylsulfone, 4-Hydroxy-4'-benzenesulfonyloxydiphenylsulfone, 1.1-bis(p-hydroxyphenyl)propane, 1.1-bis(p-hydroxyphenyl)pentane, 1.1-bis(p-hydroxyphenyl) Hexane, 1.1-bis(p-hydroxyphenyl)cyclohexane, 2.2-bis(p-hydroxyphenyl)propane, 2.2-bis(p-hydroxyphenyl)butane, 2.2-bis(p-hydroxy phenyl)hexane, 1.1-bis(p-hydroxyphenyl)-2-ethylhexane, 2.2-bis(3-chloro-4-hydroxyphenyl)
Propane, 1.1-bis(p-hydroxyphenyl)-1-phenylethane, 1.3-di[2-(p-hydroxyphenyl)-2-propyl]benzene, 1.3-di[2-(3 ,4-dihydroxyphenyl)-
2-propyl]benzene, 1.4-di[2-(p-hydroxyphenyl)-2-propyl]benzene, 4.4°-dihydroxydiphenyl ether, 4.4
-dihydroxydiphenylsulfone, 3.3'-dichloro-4,4'-dihydroxydiphenylsulfone, 3.3'-diallyl-4,4'-dihydroxydiphenylsulfone, 3.3'-dichloro-4,4'- Dihydroxydiphenyl sulfide, 2.2-bis(4-hydroxyphenyl)methyl acetate, 2.2-bis(4-hydroxyphenyl)butyl acetate, 4.4'-thiobis(2-t-butyl-5-methylphenol) , bis(3-allyl-4-hydroxyphenyl)sulfone, 4-hydroxy-4'-isopropyloxydiphenylsulfone, 3,4-dihydroxy-4'-methyldiphenylsulfone, benzyl p-hydroxybenzoate, p-hydroxybenzoic acid Examples include chlorobenzyl acid, propyl p-hydroxybenzoate, butyl p-hydroxybenzoate, dimethyl 4-hydroxyphthalate, benzyl gallate, stearyl gallate, salicylanilide, 5-chlorosalicylanilide, and the like. Examples of adhesives used in the heat-sensitive recording layer include hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, starch derivatives, gelatin, casein, polyvinyl alcohol, modified polyvinyl alcohol, polyacrylic acid, acrylic amide/acrylic ester copolymer, Acrylic acid amide/acrylic ester/methacrylic acid ternary copolymer, styrene/maleic anhydride copolymer, ethylene/maleic anhydride copolymer,
Examples include isobutylene/maleic anhydride copolymer. Furthermore, a water-resistant agent (gelling agent, cross-linking agent) may be added for the purpose of imparting water resistance to these adhesives. The heat-sensitive recording layer contains pigments such as diatomaceous earth, talc, kaolin, calcined kaolin, calcium carbonate, magnesium carbonate, calcium oxide, magnesium oxide, titanium oxide,
Zinc oxide, natural silica, synthetic silica, aluminum hydroxide,
In addition, waxes such as N-hydroxymethylstearamide, stearamide, palmitic acid amide, etc. can be used as additives to further improve sensitivity. Naphthol derivatives such as 2-hensyloxynaphthalene, biphenyl derivatives such as p-benzylbiphenyl and 4-allyloxybiphenyl, 1.2-bis(3-methylphenoxy)ethane, 2.2'-bis(4
-methoxyphenoxy) diethyl ether, bis(4-
polyether compounds such as methoxyphenyl) ether,
Diphenyl carbonate, dibenzyl oxalate, di(p) oxalate
Carbonic acid or oxalic acid diester derivatives such as -chlorobenzyl) esters can be added. It is also possible to use a mixture of two or more of these additives. In addition, higher fatty acid metal salts such as zinc stearate and calcium stearate, paraffin, oxidized paraffin, polyethylene, polyethylene oxide, stearic acid amide, and waxes such as dregs and monowax are used to prevent head wear and stickiness. Further, a dispersant such as sodium dioctyl sulfosuccinate, an ultraviolet absorber such as a benzophenone type or a benzotriazole type, a surfactant, a fluorescent dye, etc. are added as necessary. The support used in the present invention is mainly paper, and raw materials normally used in paper making, such as wood pulp, synthetic valves, fillers, sizing agents, paper strength enhancers, and dyes, may be used as necessary. It is possible. Furthermore, synthetic paper, plastic film, nonwoven fabric, fabric, processed paper such as laminated sheet, or a composite of these materials may be used.

[Effect]

By using air capsules in the present invention, it is possible to provide the intermediate layer with an optimum heat insulation effect, and the thermal efficiency in the coloring reaction is extremely improved. In addition, by adding a pigment with an oil absorption of 80 ml/100 g or more, it is possible to increase the absorption of the gaps between the air capsules, which prevents printing scum from adhering to the thermal head. Conceivable.

【Example】

Next, the present invention will be explained in more detail with reference to Examples. Note that all parts and percentages shown below are based on weight. Further, unless otherwise specified, the value indicating the amount of smear is the amount of smear after drying. Example 1 ■ Preparation of foam capsules containing air Emulsification and dispersion was carried out while introducing air into a 10% aqueous solution of ethylene-maleic anhydride copolymer, and the average outer diameter was 7 μm.
bubbles were formed. 10 parts of urea, 1 part of resorcinol, and 200 parts of water were mixed with 100 parts of this solution to form a solution, and the pH was adjusted to 3.5 using an aqueous sodium hydroxide solution. Next, 2.5 parts of a 37% formaldehyde aqueous solution was added, the liquid temperature was maintained at 55° C., stirring was continued for 4 hours, and then the mixture was cooled to room temperature to complete the encapsulation. (2) Preparation of intermediate layer coating solution A mixture consisting of the following formulation was dispersed to prepare an intermediate layer coating solution. Air capsule (as solid content) 50 parts Calcined kaolin (Ann Rex, manufactured by Engelhard, oil absorption 110ml/100g) 100 parts Styrene-butadiene copolymer latex (50% water dispersion product) 36 parts Phosphate esterified starch ( MS-4600, Japan Food Processing Type, 10% aqueous solution) 90 parts water
78 parts ■ Preparation of heat-sensitive coating liquid A mixture consisting of the following formulations was ground and dispersed in a Santo Mill until the average particle size was approximately 1 μm, and [Liquid A] and [Liquid B] were prepared.
liquid] was prepared. [Liquid A] 3-(N-methyl-N-cyclohexyl)amino-6-
Methyl-7-anirite fluorane
40 parts 10% polyvinyl alcohol aqueous solution
20 parts water
40 parts [Liquid B] Bisphenol A 50 parts 2-
Benzyloxynaphthalene 50 parts 10% borihinyl alcohol soluble in water e 50 parts water
Then, using 100 parts of the prepared [liquid A] and [liquid B], a heat-sensitive coating liquid was prepared according to the following formulation. [Liquid A] 50 parts [B
Liquid] 250 parts Zinc stearate (40% dispersion) 25 parts 10% polyvinyl alcohol aqueous solution 216 parts Calcium carbonate
50 parts water
417 parts Each of the coating solutions thus prepared was smeared on a base paper having a basis weight of 40 g/d using a Meyer bar in the following amounts to prepare heat-sensitive recording materials. Intermediate layer: 4.0 g/m Heat-sensitive recording layer: 5.5 g/" [1 (Example 2) In Example 1, the outer shape of the air capsule was
A heat-sensitive recording material was produced in the same manner as in Example 1, except that the thickness was .mu.m and the composition of the intermediate layer was as follows. Air capsule (as solid content) 20 parts Calcined kaolin (manufactured by Ansilex, Engelhard) 100 parts Styrene-butadiene copolymer latex (50% water dispersion product)
28.8 parts phosphate esterified starch (
MS-4600, Japanese food processing type, 10% aqueous solution)
72 parts water
62.4 part Example 3 In Example 1, the capsule outer shape of the air capsule was 3μ.
A heat-sensitive recording material was produced in the same manner as in Example 1, except that m was used and the composition of the intermediate layer was as follows. Air capsule (as solid content) 100 parts Calcined kaolin (Ansilex, manufactured by Engelhardt) 100 parts Styrene-butadiene copolymer latex (50% water dispersion product)
48 parts phosphated starch (M
S-4600, Japanese food processing type, 10% aqueous solution)
120 parts water
104 parts Example 4 In Example 1, the capsule outer shape of the air capsule was 20
A heat-sensitive recording material was produced in the same manner as in Example 1, except that the thickness was .mu.m and the composition of the intermediate layer was as follows. Air capsule (as solid content) 3 parts Calcined kaolin (manufactured by Ansilex, Engelhard) 100 parts Styrene-butadiene copolymer latex (50% water dispersion product)
24.7 parts phosphated starch (
MS-4600, Japanese food processing type, 10% aqueous solution)
66 parts water
53° 6 parts Comparative Example 1 A heat-sensitive recording material was produced in the same manner as in Example 1 except that the composition of the intermediate layer was as follows. Air capsule (as solid content) 200 parts Calcined kaolin (Ansilex, manufactured by Engelhard) 100 parts Styrene-butadiene copolymer latex (50% water dispersion product)
72 parts phosphated starch (M
S-4600, Japanese food processing type, 10% aqueous solution)
180 parts water
156 parts Comparative Example 2 A heat-sensitive recording material was produced in the same manner as in Example 1 except that the composition of the intermediate layer was as follows. Air capsule (as solid content) 0.5 parts calcined kaolin (
Ansilex, manufactured by Engelhard) 100 parts styrene-butadiene copolymer latex (50% water dispersion product)
25.2 parts phosphated starch (
MS-4600, Japanese food processing type, 10% aqueous solution)
63 parts water
54.6 parts Comparative Example 3 A heat-sensitive recording material was prepared in the same manner as in Example 1, except that a coating liquid for an intermediate layer was prepared by dispersing a mixture having the following composition. ROPAQUE 0P-62 (Rohm & Haas styrene-acrylic hollow particle emulsion) (as solid content) 50 parts calcined kaolin (Ansilex, Engelbar 4D) 100 parts styrene-e-butadiene copolymer latex (50% water dispersion) product)
36 parts phosphate esterified starch (MS-4600, Japan Food Processing Type, 1096 aqueous solution)
90 parts water
78 parts Comparative Example 4 Oil absorption of 46 m instead of calcined kaolin in Example 1
A heat-sensitive recording material was prepared in the same manner as in Example 1 except that 1/100 g of kaolin was used. Comparative Example 5 A heat-sensitive recording material was produced in the same manner as in Example 1 except that a coating liquid for an intermediate layer was prepared by dispersing a mixture having the following composition. Calcined kaolin (manufactured by Ansilex and Engelhard) 100 parts Styrene-butadiene copolymer latex (50% water dispersion product)
24 parts phosphated starch (M
S-4600, Japanese food processing type, 10% aqueous solution)
60 parts water
52 copies The heat-sensitive recording material thus prepared was treated with a supercalender to give a Bekk smoothness of 300 to 400 seconds, and the recording density and printing residue were evaluated using a GmFAX tester. The results are shown in Table 1. . The tester used was a thermal head made by Taishoku Denki (TH-PMD) with a dot density of 8 dots/mm and a head resistance of 1045Ω, with a head voltage of 20cm and a power-on time of 0.
6ms and 1. Printing was performed at 2 ms, and the recording density was measured using a Macbeth RD-918 reflection densitometer. Also,
The adhesion of printing scum to the thermal head is caused by a head voltage of 20
V: The thermal head was smeared when solid printing was performed on two A4 samples using a current application time of 1.2 ms. Evaluation of printing residue in Table 1: ○, adhesion of printing residue is not observed. Δ: A small amount of printing residue is observed. ×: There is a lot of printing residue attached.

【Effect of the invention】

As is clear from the results in Table 1, the heat-sensitive recording material of the present invention has high thermal resistance and recording density, and also has a small amount of adhesion of printing scum.

Claims (1)

[Scope of Claims] 1. In a heat-sensitive recording material in which a heat-sensitive recording layer is provided on a support, a capsule containing air and a pigment having an oil absorption amount of 80 ml/100 g or more are provided between the support and the heat-sensitive recording layer. and a heat-sensitive recording material comprising an intermediate layer containing an adhesive as a main component. 2. The outer diameter of the capsule containing air is 2 μm or more and 20 μm.
The heat-sensitive recording material according to claim 1, characterized in that it is less than or equal to m.