JPH04261892A - Thermal recording material - Google Patents

Abstract

PURPOSE:To prevent the lowering of whiteness due to the reduction of the particle size of the thermal color forming component in a thermal recording layer and the adhesion of contaminant to a thermal head in a thermal recording material. CONSTITUTION:In a thermal recording material having a support, a thermal recording layer (containing a dye precursor, a developer and a binder) and the undercoat layer formed between the support and the thermal recording layer and containing a filler and a binder, the filler in the undercoat layer contains basic calcium carbonate and a powder with oil absorbency (JIS K 5101) of 80ml/100g or more.

Description

Description: [0001] The present invention relates to a heat-sensitive recording material with excellent recording sensitivity. More specifically, the present invention relates to a heat-sensitive recording material that has high whiteness and is excellent in recording sensitivity at least in terms of lees adhesion to a recording head. [0002] Thermal recording method has been highly praised for its advantages, such as being able to obtain colored images simply by heating, and the ability to make this recording device relatively simple and compact. It is widely used as a recording method. Particularly in recent years, facsimile machines using such heat-sensitive recording methods have been
As printer equipment continues to improve, high-speed recording, which was previously considered difficult, is now possible. As the speed of such devices increases, the heat-sensitive recording materials used therein are required to further improve the recording sensitivity, and many proposals have been made in this regard. Such heat-sensitive recording materials are generally made by forming a heat-sensitive recording layer containing a binder and a thermochromic substance as a single layer or multiple layers on a support such as paper, plastic film, or synthetic paper. used. In order to improve the recording sensitivity of the heat-sensitive recording material having the above-mentioned structure, conventional methods include 1) addition of a low melting point thermofusible substance, 2) improvement of surface smoothness, and 3) addition of a coloring component-dye precursor. Efforts have been made to increase the amount of color developer, color developer, and sensitizer, but all of these methods increase the adhesion of molten components in the heat-sensitive recording layer to the thermal head, causing printing problems. It had the following drawbacks. Therefore, in order to eliminate such drawbacks, as a means of improving recording sensitivity without increasing the amount of coloring component, it is necessary to reduce the average particle diameter of the thermal coloring component particles to 2.0 μm or less. It is proposed to make it smaller (
JP-A No. 57-476983, etc.). [0006] The fine particles of such thermal coloring components (particularly zero
．． (7 μm or less), the recording sensitivity is dramatically improved. However, the color of the dispersion becomes black, and the whiteness of the recording paper using it is extremely reduced.
It is known that storage for months or half a year causes problems such as a decrease in whiteness, and as a result, it loses its practical value as a recording paper. [0007] As a method for preventing the reduction in whiteness due to the formation of fine particles of thermally colored components, it has been proposed to increase the temperature during dispersion to prevent the reduction in whiteness (JP-A-54-9
No. 8253), which had the disadvantage of easily inducing agglomeration of the dispersion and was not practical. [0008] It has also been proposed to prevent a decrease in whiteness by adjusting the pH of the dye dispersion to 8 to 11 (Japanese Unexamined Patent Application Publication No. 1983-1995).
6-40585), the average particle size of the thermal coloring component is 0.
If the diameter is less than 7 μm, the effect is small, and the solubility of the dye in water increases, which has the disadvantage that the whiteness tends to decrease. [0009] In addition, as methods other than the above, there is a method of adding amines to the coating liquid (Japanese Patent Publication No. 48-101943), a method of adding acetylene alcohol or acetylene glycol (Japanese Patent Publication No. 58-34307). ),
and a method of dispersing a thermochromic component together with a water-soluble polymer to seal the active interface of the dispersed material during pulverization (JP-A-5
No. 4-70056, Japanese Patent Publication No. 45-14039, Japanese Patent Application Laid-Open No. 48-17344), etc., but all of these methods have been proposed to reduce the average particle size of the thermally colored component that is the dispersant. When the particles become fine particles with a diameter of 0.7 μm or less, it is not a very effective method, and when a heat-sensitive coloring layer coating solution containing these particles is applied onto a substrate, whiteness decreases, and whiteness decreases over time. It was not a practical technology because it had drawbacks such as causing problems. [0010]Also, a method of keeping the pH of the coating liquid alkaline has been proposed (Japanese Unexamined Patent Application Publication No. 11141/1989), but this method increases the solubility of the color developer in water in the coating liquid and reduces the whiteness. The disadvantage was that it actually decreased. [0011] Also, methods of adding basic inorganic pigments (JP-A-49-90142, JP-A-63-67184)
No. 1-209182, JP-A No. 2091-1
No. 92986) has been proposed, but all of these methods have the drawback of causing a decrease in sensitivity, which is thought to be due to reaction with the color developer. Furthermore, 1 to 5% of calcium carbonate or calcium hydroxide is added to the intermediate layer between the heat-sensitive recording layer and the support.
Method using calcium carbonate containing (JP-A-63-63
7184, Japanese Patent Application Laid-Open No. 2-178082), however, this method does not have a sufficient effect of preventing a decrease in whiteness, especially when the thermal coloring component has fine particles with an average particle size of 0.7 μm or less. There was a drawback that no effect was observed and the sensitivity was significantly lowered. [0013] As mentioned above, in conventional heat-sensitive recording materials, there is a problem in that the whiteness of the recording material decreases when the thermal coloring component is made into fine particles in order to obtain high recording sensitivity. There was a point. The present invention solves the above-mentioned problems and provides a high-quality heat-sensitive recording material that exhibits less adhesion of residue to a thermal head, high recording sensitivity, and excellent continuous recording performance. Means for Solving the Problems The present inventors provided an undercoat layer containing a filler and a binder between a support and a heat-sensitive recording layer, and as a binder for this undercoat layer, The present invention has been completed by discovering that the above-mentioned problems can be solved by using a product containing basic calcium carbonate and powder having an oil absorption amount of a specific value or more as components. That is, the heat-sensitive recording material of the present invention comprises a support, a substantially colorless dye precursor formed on at least one surface of the support, and a dye precursor which is reacted with the paint precursor under heating. a heat-sensitive recording layer containing a color developer and a binder that develops the color; and an undercoat layer formed between the support and the heat-sensitive recording layer and containing a filler and a binder; The filler in the undercoat layer is basic calcium carbonate and 80ml/ml measured according to JISK 5101.
It is characterized by containing as a main component powder having an oil absorption amount of 100 g or more. [Function] In the heat-sensitive recording material of the present invention, the undercoat layer provided between the support and the heat-sensitive recording layer contains basic calcium carbonate together with a powder having an oil absorption amount of a specific value or more. By this, the pH of the surface of the undercoat layer can be stably maintained at a slightly alkaline level, thereby suppressing the coloring reaction between the acidic color developer component in the heat-sensitive recording layer and the dye precursor, resulting in high whiteness. can be held stably. The above-mentioned effect of suppressing the color development reaction of the present invention and the effect of maintaining high whiteness associated with it are particularly remarkable when the particle size of the dispersed particles of the color developer and dye precursor in the heat-sensitive recording layer is 0.7 μm or less. It is demonstrated in This is thought to be because the reactivity of the particle interface increases due to the miniaturization of the color forming component particles, and it becomes strongly influenced by the layer below the heat-sensitive recording layer, that is, the undercoat layer. In particular, when 3-(N-isoamyl-N-ethylamino)-6-methyl-7-anilinofluorane is used as the dye precursor, the above-mentioned effects of the undercoat layer of the present invention are significantly exhibited. is recognized. The basic calcium carbonate used in the present invention has the following chemical formula: Ca3(CO3)2(OH)2.1.5H2O, but its anhydride may be used. [0019] Such basic calcium carbonate is a plate-like crystal, and is disclosed in Japanese Patent Application Laid-Open Nos. 60-71523 and 1982-
No. 32130, JP-A-62-113718, and Paper and Pulp Technology Times (July 1988 issue, pp. 29-32)
etc. are disclosed. Basic calcium carbonate is a compound that is different from ordinary calcium carbonate (CaCO3) both in its chemical structure and in its chemical and physical properties. Basic calcium carbonate is also a different substance from different mixtures of normal calcium carbonate and calcium hydroxide. That is, in the present invention, if ordinary light calcium carbonate alone or a simple mixture of light calcium carbonate and calcium hydroxide is used instead of basic calcium carbonate, the above effects of the present invention cannot be obtained. [0021] Basic calcium carbonate in the present invention,
Oil-absorbing powder has excellent absorption properties for scum generated during heat-sensitive coloring operations.Although the mechanism of this scum absorption is not fully understood, when forming the undercoat layer, basic carbonic acid Some of the calcium dissolves in water,
The calcium ions generated thereby form weak bonds between the oil-absorbing powders during drying of the coating layer, resulting in the formation of an undercoat layer with relatively high porosity, and a large number of microscopic particles. The pores are thought to promote the high oil absorption of the oil-absorbing powder as well as the absorption of scum generated during thermochromic recording operations. In the heat-sensitive recording layer of the present invention, the support is
Can be selected from paper, plastic film, synthetic paper, metal foil, and composite laminates thereof, and generally has a basis weight of 3
A sheet material having a weight of 0 to 80 g/m2 and a thickness of 30 to 80 μm is used. [0023] An undercoat layer is formed on at least one side of the support. This undercoat layer contains a filler and a binder as main components. In the present invention, the undercoat layer filler is basic calcium carbonate powder and JIS K 51
The main component is powder having an oil absorption amount of 80 ml/100 g or more according to the 01 method. [0024] In the present invention, the oil-absorbing powder contained in the undercoat layer is 80 ml/100 g or more, preferably 80 ml/100 g or more, preferably 80 ml/100 g or more.
Preferably, it contains at least one of inorganic and organic pigments having an oil absorption of ~150 ml/100 g, such as calcined clay, calcium carbonate, silicic acid, aluminum silicate, white carbon, magnesium carbonate, and urea-formaldehyde resin filler. . If the oil absorption amount is less than 80 ml/100 g, the resulting heat-sensitive recording material will have insufficient dregs adhesion prevention properties. The total weight of basic calcium carbonate and oil-absorbing powder in the undercoat layer of the present invention is preferably 70 to 95% of the total solid weight of the undercoat layer. Moreover, the content of basic calcium carbonate in the undercoat layer of the present invention is preferably 0.5 to 50%, more preferably 1 to 20%, based on the weight of the oil-absorbing powder. As the binder contained in the undercoat layer of the present invention, generally known water-soluble polymer substances and aqueous emulsions are used. Specifically, polyvinyl alcohol, methyl cellulose, hydroxyethyl cellulose, starch,
Starch derivative, styrene-maleic anhydride copolymer,
Isobutylene-maleic anhydride copolymer, polyamide,
At least one selected from SBR latex, polystyrene-acrylic acid ester emulsion, polyvinyl acetate emulsion, etc. is used. [0027] Generally, the weight of the undercoat layer is 0.5 to 15 g/
m2 (dry) is preferred. The undercoat layer is provided between the support and the heat-sensitive recording layer. That is, in order to form the undercoat layer, it is sufficient to prepare a coating liquid containing the above-mentioned filler and a binder, apply this to the desired surface of the support, and dry it. As a coating method for the undercoat layer, known coating methods such as an air knife method, a blade method, a gravure method, a roll rotor method, a spray method, a dip method, a bar method, and an extrusion coating method can be used. In the heat-sensitive recording material of the present invention, a heat-sensitive recording layer is formed on the undercoat layer. This heat-sensitive recording layer contains a substantially colorless dye precursor, a color developer that reacts with the dye precursor under heating to develop color, and a binder. Dye precursors used in the present invention include those used in general pressure-sensitive recording paper, heat-sensitive recording paper, etc., such as (1) triarylmethane compounds, such as 3,3
(2) Diphenylmethane compounds, such as 4,4'-bis-dimethylaminobenzhydrin benzine ether, N-2,4,5- (3) xanthene compounds such as rhodamine B-anilinolactam, 3-
diethylamino-7-dibenzylaminofluorane, 3
-diethylamino-7-butylaminofluorane, 3-
Diethylamino-7-(2-chloroanilino)fluorane, 3-piperidino-6-methyl-7-anilinofluorane, 3-ethyl-tolylamino-6-methyl-7-anilinofluorane, 3-cyclohexyl-methylamino- 6-Methyl-7-anilinofluorane, 3-diethylamino-6-chloro-7-(β-ethoxyethyl)aminofluorane, 3-diethylamino-6-chloro-7-(
γ-chloropropyl)aminofluorane, 3-ethyl-
It can be selected from isoamylamino-6-methyl-7-anilinofluorane, 3-dibutylamino-7-chloroanilinofluorane, and the like. The dye precursor is generally present in the heat-sensitive recording layer in an amount of 5 to 20% based on its total dry weight.
It is preferable that it is contained in a proportion of . [0030] These may be used alone or as a mixture of two or more. The dye precursor is appropriately selected and used depending on the purpose and desired properties of the heat-sensitive recording material, but 3-dibutylamino-6-methyl-7-anilinofluorane is particularly used because it has an excellent effect of improving sensitivity through fine particle formation. ,3
-(N-isoamyl-N-ethylamino)-6-methieu-7-anilinofluorane is preferably used. As the color developer used in the present invention, phenol derivatives and aromatic carboxylic acid derivatives are preferred, and bisphenols are particularly preferred. Preferred phenols include p-octylphenol, p-tert-butylphenol, and p-tert-butylphenol.
Phenylphenol, 1,1-bis(p-hydroxyphenyl)propane, 2,2-bis(p-hydroxyphenyl)pentane, 1,1-bis(p-hydroxyphenyl)hexane, 2,2-bis(p- hydroxyphenyl)hexane, 1,1-bis(p-hydroxyphenyl)
Examples include -2-ethyl-hexane, 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane, and dihydroxydiphenyl ether. Preferred aromatic carboxylic acid derivatives include p-hydroxybenzoic acid, butyl p-hydroxybenzoate, 3,5-di-tert-butylsalicylic acid,
Examples thereof include 3,5-di-α-methylbenzylsalicylic acid and polyvalent metal salts of the above-mentioned carboxylic acids. It is generally preferable that the color developer is contained in the heat-sensitive recording layer in a proportion of 5 to 40% based on the weight of the dye precursor. In the heat-sensitive recording material of the present invention, surfactants, polyacrylamide, polyvinylpyrrolidone, polyvinyl alcohol, styrene-maleic anhydride copolymer, etc. are added to the heat-sensitive recording layer within a range that does not impair the effects of the present invention. Water-soluble synthetic polymer compounds such as hydroxyethyl cellulose, starch derivatives, gelatin, and water-soluble natural polymer compounds or their derivatives such as casein may be used, and various auxiliary agents such as antifoaming agents may be added. I can do it. Preferably, at least one of the dye precursor dispersion and the color developer dispersion is prepared using various wet crushers such as a sand grinder, an attritor, a ball mill, and a cobo mill. It is preferable that the average particle size of is 0.7 μm or less. In the present invention, when preparing a paint for a heat-sensitive recording layer, separately prepared dispersions of a dye precursor and a color developer are mixed with each other, and a sensitizer, a sensitizer,
Add inorganic pigments, waxes, metallic soaps, and if necessary, ultraviolet absorbers, antioxidants, or latex binders. There is no problem in adding the above additives during the dispersion operation of each dispersion. Waxes contained in the heat-sensitive recording layer include paraffin wax, carnauba wax, microcrystalline wax, polyethylene wax, and
Higher fatty acid amides such as stearic acid amide, ethylene bisstearamide, higher fatty acid esters, etc. can be used, and the content thereof is preferably 5 to 20% based on the dry weight of the heat-sensitive recording layer. As the metal soap, higher fatty acid polyvalent metal salts, ie, zinc stearate, aluminum stearate, calcium stearate, and zinc oleate can be used, and the content thereof is based on the dry weight of the heat-sensitive recording layer.
It is preferably 5 to 20%. Inorganic pigments include kaolin, calcined kaolin, talc, waxite, diatomaceous earth,
Calcium carbonate, aluminum hydroxide, magnesium hydroxide, magnesia, titanium oxide, barium carbonate, etc. can be used, and the content thereof is preferably 5 to 30% based on the dry weight of the heat-sensitive recording layer. As a sensitizer, p-benzylbiphenyl,
Dibenzyl terephthalate, phenyl 1-hydroxy-2-naphthoate, dibenzyl oxalate, di-adipate
o-chlorobenzyl, 1,2-di(3-methylphenoxy)ethane, di-p-chlorobenzyl oxalate, bis(p-methylbenzyl) oxalate, etc. can be used, and the content thereof is determined in the heat-sensitive recording layer. 5-40 for the dry weight of
% is preferable. [0040] As the binder used in the heat-sensitive recording layer,
Commonly water-soluble materials include polyvinyl alcohol, hydroxyethyl cellulose, hydroxypropyl cellulose, ethylene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer, polyacrylic acid, and starch. , casein, gelatin, etc. In addition, for the purpose of imparting water resistance to these binders, water resistance imparting agents may be added, or hydrophobic emulsions, specifically styrene-butadiene rubber lux,
Acrylic resin emulsion etc. can also be added. Generally, the content of the binder in the heat-sensitive recording layer is preferably 5 to 15% based on the dry weight of the heat-sensitive recording layer. Generally, the weight (dry) of the heat-sensitive recording layer is 3
It is preferable that it is 8 g/m2. [0042] To form the heat-sensitive recording layer, a coating solution containing the above-mentioned components may be prepared, coated on the undercoat, and dried. As this coating method, known coating methods such as an air knife method, a blade method, a gravure method, a roll coater method, a spray method, a dip method, a bar method, and an extrusion method can be used. [Examples] Next, the present invention will be explained in more detail with reference to Examples, but these are not intended to limit the scope of the present invention. In addition, unless otherwise specified, "part" in the examples is "
Parts by weight. Example 1 An undercoat layer coating solution was prepared by the following method. Growth
minutes
quantity water

10
0 parts Calcined clay (trademark: manufactured by Ancilex Engelhardt, 100 parts)
Oil absorption amount 90ml/
100g)
Basic calcium carbonate (manufactured by Chichibu Lime Co., Ltd.,
5th part
Oil absorption: 7
0ml/100g) 10 parts of 10% polyvinyl alcohol aqueous solution (trademark: GL05, manufactured by Nippon Gosei Co., Ltd.) [0045] After dispersing the above composition in a homogenizer for 5 minutes, 150 parts of 10% polyvinyl alcohol (GH17) aqueous solution was mixed therewith. An undercoat layer coating solution was prepared. [0046] This undercoat layer coating liquid was applied to the felt side of a high-quality paper having a basis weight of 50 g/m2 so that the dry coating amount was 7 g/m2, and dried to form an undercoat layer. On the other hand, a coating solution for a heat-sensitive coloring layer was prepared according to the following steps. First, dispersions A and B having the following compositions were prepared, and these dispersions were used to prepare a coating solution for forming a heat-sensitive recording layer. ■Preparation of dispersion A
minutes
Amount 3-(N
-isoamyl-N-ethylamino)-
10 copies
Anilinofluorane

Polyvinyl alcohol 10% aqueous solution
30 parts (molecular weight 500, degree of saponification 90%)

Di(p-methylbenzyl) oxalate
20 parts water

40 parts of this composition was charged into a vertical sand mill (manufactured by Imex Corporation, Sand Grinder), and a diameter of 1.2
A dispersion and refinement operation using glass beads of 0.6 mm in diameter was performed for 30 minutes, and then the composition was charged into a horizontal sand mill (Ultra Visco Mill manufactured by Imex), and dispersion was carried out using glass beads of 0.6 mm in diameter as a dispersion medium. The micronization operation was performed for 120 minutes, and the average particle size of the dispersed particles was set to 0.5 μm. ■Preparation of dispersion B
minutes
Amount 2,2-
Bis(p-hydroxyphenyl)propane
20 parts 10% polyvinyl alcohol aqueous solution
20 copies
(Molecular weight 500, degree of saponification 90%)

water

60 parts of this composition was dispersed in the same manner as in the preparation of dispersion A, and the average particle size of the dispersed particles was 0.5 μm. ■Preparation of heat-sensitive recording layer coating solution The above dispersion A
100 parts, and 100 parts of dispersion B, 40 parts of calcium carbonate, and 100 parts of 10% polyvinyl alcohol aqueous solution.
A coating solution was prepared by mixing the two parts and stirring. [0051] This coating solution is applied onto the undercoat layer so that the coating amount after drying is 6.5 g/m2, and dried to form a heat-sensitive coloring layer, which is then calendered to form a heat-sensitive recording paper. was manufactured. The recording sensitivity, whiteness, and dregs absorbency of the heat-sensitive recording paper thus obtained were measured and evaluated. [0053] For measuring the particle diameters of the dispersed particles in Dispersions A and B, LPA-3000/3100 manufactured by Otsuka Electronics Co., Ltd. was used. [0054] In measuring recording sensitivity, NEC Corporation
Manufactured high-speed facsimile: Nefax 23, standard chart No. 2 of the Institute of Image Electronics Engineers. 2, and the color density at that time was measured using a Macbeth densitometer RD-914, and this measured value was taken as a value representative of the recording sensitivity of the thermal recording paper. A Hunter whiteness meter (using a blue filter) was used to measure the whiteness. [0056] To evaluate the waste absorbability, a high-speed facsimile Nefax 23 manufactured by NEC Corporation was used and the standard chart No. 1 of the Institute of Image Electronics Engineers was used. 2, print 1000 sheets,
At this time, the amount of debris adhering to the thermal head was visually evaluated. The test results are shown in Table 1. Example 2 The same operations and measurements as in Example 1 were carried out. However, the coating solution for the undercoat layer was prepared as follows. Growth
minutes
quantity water

10
0 parts Silica (Trademark: Fine Seal S
P-10
100 copies
Manufactured by Tokuyama Soda Co., Ltd., oil absorption 150ml/10
0g) Basic calcium carbonate (Chichibu Lime Co., Ltd.)
5th part

Oil absorption: 70ml/100g) 10% polyvinyl alcohol aqueous solution
10 copies
After dispersing this composition with a homogenizer for 5 minutes, add 1
150 parts of a 0% polyvinyl alcohol aqueous solution was mixed to prepare an undercoat layer coating solution. The test results are shown in Table 1. Comparative Example 1 The same operations and measurements as in Example 1 were carried out. However, the coating solution for the undercoat layer was prepared as follows. Growth
minutes
quantity water

10
0 parts Calcined clay (trademark: Ansilex)
100 parts 10% polyvinyl alcohol aqueous solution
10 parts This composition was dispersed for 5 minutes using a homogenizer, and then 50 parts of a 10% polyvinyl alcohol aqueous solution was mixed thereto to prepare an undercoat layer coating solution. The test results are shown in Table 1. Comparative Example 2 The same operations and measurements as in Example 1 were carried out. However, the coating solution for the undercoat layer was prepared as follows. Growth
minutes
quantity water

10
0 parts Magnesium hydroxide (trademark: P
TH-10
100 copies
Manufactured by Asahi Kasei, oil absorption: 60ml/100g)
Basic calcium carbonate (Chichibu Lime Co., Ltd.)
5th part
Oil absorption: 70ml/100g) 10% polyvinyl alcohol aqueous solution
10 parts This composition was dispersed for 5 minutes using a homogenizer, and then 150 parts of a 10% polyvinyl alcohol aqueous solution was mixed thereto to prepare an undercoat layer coating solution. The test results are shown in Table 1. Comparative Example 3 The same operations and measurements as in Example 1 were carried out. However, the coating solution for the undercoat layer was prepared as follows. Growth
minutes
quantity water

10
0 parts Calcined clay (trademark: Ansilex)
100 parts light calcium carbonate (
Trademark: Callite SA
10 parts Manufactured by Shiraishi Central Research Institute Co., Ltd., oil absorption: 60ml/100g) 10
% polyvinyl alcohol aqueous solution
10 copies
This composition was dispersed for 5 minutes using a homogenizer, and then 150 parts of a 10% polyvinyl alcohol aqueous solution was mixed thereto to prepare an undercoat layer coating solution. The test results are shown in Table 1. Comparative Example 4 The same operations and measurements as in Comparative Example 1 were carried out. However, the average particle diameter of the dispersed particles when preparing dispersions A and B was 1.0 μm. The test results are shown in Table 1. [Table 1] [Effects of the Invention] The heat-sensitive recording material of the present invention has excellent recording sensitivity, high whiteness, and little residue adhesion to the head.
It has excellent performance in practical use.

Claims (1)

[Claims] 1. A support; and at least one of the supports.
a heat-sensitive recording layer formed on the surface and containing a substantially colorless dye precursor, a color developer that reacts with the dye precursor under heating to develop a color, and a binder; an undercoat layer formed between the heat-sensitive recording layer and containing a filler and a binder; the filler in the undercoat layer is basic calcium carbonate; A heat-sensitive recording material characterized by containing as a main component a powder having an oil absorption amount of 100 g or more.