JPH03184892A - Thermal recording material - Google Patents

Abstract

PURPOSE:To obtain a thermal recording material excellent in the image stability to oil or a plasticizer and also excellent in running properties by adding satin white to a recording layer and adding polyvinyl alcohol to an overcoat layer. CONSTITUTION:The use ratio of the color former and coupler in a recording layer is appropriately selected according to the kinds of the color former and the coupler and water is used as a dispersing medium and the color former and the coupler are together or separately dispersed by a stirring grinder such as a sand grinder while an adhesive and various auxiliaries are added thereto to prepare a coating solution. The obtained coating solution is applied to raw paper and dried to obtain a thermal recording material. An overcoat layer containing polyvinyl alcohol is provided on the thermal recording material after the thermal layer is formed. At this time, silicon modified polyvinyl alcohol is used to make oil resistance or plasticizer resistance especially excellent.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field" The present invention relates to a heat-sensitive recording medium, and particularly to a heat-sensitive recording medium that has excellent stability of recorded images and good recording running properties.

"Prior Art" Conventionally, thermal recording materials capable of developing color using thermal energy of a thermal head are well known. Such heat-sensitive recording media are relatively inexpensive, the recording device is compact, and maintenance is relatively easy, so they are used not only as recording media for facsimiles and various calculators, but also in a wide range of fields such as heat-sensitive recording media. . However, it has problems in fingerprint resistance and solvent resistance, and has the disadvantage that, for example, when the recording layer comes into contact with human sebum or solvent, the recording density decreases and unnecessary coloration called background fog occurs.

As a method to overcome these drawbacks, a method is proposed in which an aqueous emulsion of a resin having film-forming ability and chemical resistance is coated on the heat-sensitive recording layer (Japanese Patent Laid-Open No. 12834/1983).
7), a method of applying a water-soluble polymer compound such as polyvinyl alcohol (Japanese Utility Model Publication No. 125354/1983), and the like have been proposed. However, the current situation is that improvements come with new drawbacks, and that satisfactory results are not necessarily obtained.

For example, when applying a water-based resin coating on a heat-sensitive recording layer, it is necessary to limit the drying temperature to avoid coloring of the recording layer due to high-temperature drying, which inevitably results in insufficient curing of the resin layer and A phenomenon in which the recording head and the resin layer stick together occurs.

In addition, tack thermal paper for barcodes, whose demand has been increasing recently for PO3, is required to be resistant to oil and plasticizers contained in vinyl chloride film, and high-quality thermal recording materials that can meet these demands are required. The current situation is that this has not yet been achieved.

``Problems to be Solved by the Invention'' The present invention aims to obtain a heat-sensitive recording material that does not cause adhesion to the recording head and has extremely excellent stability of recorded images against oil, plasticizers, etc. .

"Means for Solving the Problems" The present inventors have developed a heat-sensitive recording medium in which a recording layer containing at least a coloring agent and a coloring agent that causes the coloring agent to develop color when heated, and an overcoat layer are sequentially provided on a support. The present inventors have discovered that these objects can be very effectively achieved by containing satin white in the recording layer and polyvinyl alcohol in the overcoat layer, and have completed the present invention. Ta.

"Function" The present invention has an important feature in that the heat-sensitive recording layer contains satin white and the overcoat layer contains polyvinyl alcohol. When a heat-sensitive recording medium is formed with such a structure, In particular, it shows excellent performance in oil resistance and plasticizer resistance.

The reason for such excellent performance is not necessarily clear, but the reason why it exhibits such excellent performance is that Sachin Why 1 contained in the heat-sensitive layer
~ and the polyvinyl alcohol contained in the overcoat layer gel at the interface, making it difficult for the overcoat layer paint to penetrate into the heat-sensitive layer when applying the overcoat layer paint, resulting in an overcoat layer with excellent barrier properties. It is thought that this is because it can be obtained.

Sachin white used in the heat-sensitive layer of the present invention is an artificial pigment obtained by reacting aluminum sulfate and calcium hydroxide, and its chemical composition is generally 3CaOHAl2
It is expressed as O3.3CaSO4' 328zO, and its composition ratio changes depending on the mixing ratio of raw materials.

The proportion of Sachin White in the heat-sensitive layer is determined depending on the target recording density and the type of polyvinyl alcohol in the overcoat layer to be combined, and is not necessarily limited to 0.5 to 30% by weight. %, preferably in the range of 2 to 10% by weight.

In the present invention, the color forming material constituting the heat-sensitive recording layer is not particularly limited, and any combination that causes a color reaction due to the thermal energy generated by the heat-sensitive head can be used. For example, colorless or light-colored materials can be used. Combinations of basic dyes and inorganic or organic acidic substances, combinations of higher fatty acid metal salts such as ferric stearate and phenols such as gallic acid, diazonium compounds, coupler compounds, and basic atmosphere during thermal melting. Examples thereof include heat-sensitive recording materials obtained in combination with the compounds shown in Table 1.

However, the combination of a colorless or light-colored basic dye and an acidic substance has extremely excellent recording properties, and the effects of the present invention are fully demonstrated.
Particularly preferred. Various kinds of colorless to light-colored basic dyes are known, and the following are exemplified.

3.3-bis(p-dimethylaminophenyl)6-dimethylaminophthalide, 3,3-bis(p-dimethylaminophenyl)phthalide, 3-(p=nidimethylanophenyl)-3-(12-dimethylindole) -3-yl)phthalide, 3-(p-dimethylaminophenyl)-3-(
2-methylindol-3-yl)phthalide, 3.3-
Bis(1,2-dimethylindol-3-yl)5-dimethylaminophthalide, 3,3-bis(1゜2-dimethylindol-3-yl)-6-dimethylagonoklide, 3,3-bis( 9-Ethylcarbazol-3-yl)-6-dimethylaminophthalide, 3,3-bis(2-
phenylindol-3-yl)-6-dimethylaminophthalide, 3-p-dimethylaminophenyl-3-(1
-Methylpyrrol-3-yl)-6-'; triallylmethane dyes such as methyla5-nophthalide, 4.4'bis-dimethylaguinobenzhydrylbenzyl ether, N-
Halophenyl-leukoolamine, N-245-1-I
Diphenylmethane dyes such as J chlorophenyl leuco auramine, thiazine dyes such as benzoyl leucomethylene blue and p-nitrobenzoyl leucomethylene blue, 3-methyl-spiro-dinaphthopyran, 3-ethyl-
Spiro-dinaphthopyran, 3-phenyl-spiro-dinaphthopyran, 3-hensyl-spiro-dinaphthopyran, 3
Spiro dyes such as -methyl-naphtho(6'-methoxybenzo)spiropyran, 3-propyl-spirodibenzopyran, Rhoda 5-B-anilinolactam, Rhoda Dan (
Lactam dyes such as p-nitroanilino)lactam, rhodapoly(0-chloroanilino)lactam, 3-dimethylamino-7-medoxyfluoran, 3-diethylamino-6-medoxyfluorane, 3-diethylamino 7
-Medoxyfluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-6,7-dimethylfluorane, 3-(N
-ethyl-P-)luidino)-7methylfluorane, 3
-diethylamino-7-N-acetyl-N-methylaminofluorane, 3-diethylamino-7-N-methylaminofluorane, 3-diethylamino-7-dibenzofluorane, 3-diethylamino-7-N-methyl-
N-hensilua 5nofluorane, 3-diethyl 7mi/-
7-N-chloroethyl-N-methylaminofluorane,
3-diethylamino-7-N-diethylaminofluorane, 3-(N-ethyl P-)luidino)-6-methyl-7
-phenylaminofluorane, 3-(N-ethyl-p-
toluidino)-6-methyl-7-(p-1-luidino)
Fluoran, 3-diethylamino-6-methyl-7phenylaminofluoran, 3-dibutylamino-6-methyl-7-phenylaminofluoran, 3-dipentylamino-6-methyl-7-phenylaminofluoran, 3
-diethylamino-7-(2-carpomethoxyphenylamino))fluorane, 3-(N-ethyl-N-isoamylamino)6-methyl-7-phenylaminofluorane, 3-(N-cyclohexyl-N-methyl amine) 6
-Methyl-7-phenylaminofluorane, 3-pyrrolidino-6-methyl-7-phenylaminofluorane, 3
-piperidino-6-methyl-7phenylaminofluorane, 3-diethylamino-6-methyl-7-xylidinofluorane, 3-diethylamino-7-(o-chlorophenylamino)fluorane, 3-dibutylamino-7- (
Fluoran dyes such as 0-chloroanilino[)) fluoran, 3-pyrrolidino-6-methyl-7-P-butylphenylaminofluoran, etc.

In addition, various inorganic or organic acidic substances are known that color when they come into contact with basic colorless dyes. substance, 4
-tert-butylphenol, 4-hydroxydiphenoxide, α-naphthol, β-naphthol, 4-hydroxyacetophenol, 4-tert-octylcatechol, 2゜2'-dihydroxydiphenol, 2,2
'-methylenebis(4-methyl-6tert-isobutylphenol L4,4'-isopropylidenebis(2
tert-butylphenol), 4. 4'-5ec
Butylidene diphenol, 4-phenylphenol, 4
．． 4'-isopropylidene diphenol (bisphenol A), 4-hydroxyphenyl 4'-isopropoxyphenylsulfone, 2゜2'-methylenebis(4-chlorophenol), Hyde I''quinone, 4.4'-cyclohexyl Phenolic compounds such as dendiphenol, hensyl 4-hydroxybenzoate, dimethyl 4-hydroxyphthalate, hydroquinone monohensyl ether, novolac type phenolic resin, phenol polymer, benzoic acid, p-tert-butylbenzoic acid, trichlorobenzoic acid , terephthalic acid, 3-sec-butyl 4-hydroxybenzoic acid, 3-cyclohexyl 4-hydroxybenzoic acid,
3,5-dimethyl-40 hydroxybenzoic acid, salicylic acid, 3-isopropylsalicylic acid, 3-tert-butylsalicylic acid, 3-benzylsalicylic acid, 3-(α-methylhensyl)salicylic acid, 3-chloro-5-(α-methylbenzyl ) salicylic acid, 3,5-di-tert-butylsalicylic acid, 3-
Aromatic carboxylic acids such as phenyl-5-(α,α-dimethylbenzyl)salicylic acid, 3,5-di-α-methylhensylsalicylic acid, and these phenolic compounds, aromatic carboxylic acids such as zinc, magnesium, aluminum, calcium. , organic acidic substances such as salts with polyvalent metals such as titanium, manganese, tin, and nickel.

In the heat-sensitive recording material of the present invention, the ratio of the color former and color former in the recording layer is appropriately selected depending on the type of color former and color former used, and is not particularly limited. For example, when using a basic colorless dye and an acidic substance,
In general, 1 to 50 parts by weight, preferably 1 to 10 parts by weight, of acidic substances are used per part by weight of basic colorless dye.

To prepare a coating solution containing these substances, the coloring agent and the coloring agent are generally dispersed together or separately using water as a dispersion medium using a stirring/pulverizing machine such as a ball mill, attritor, or sand grinder, and then applied. Prepared as a liquid.

This coating liquid contains starches, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, gum arabic, and adhesives.
Polyvinyl alcohol, diisobutylene/maleic anhydride copolymer salt, styrene/maleic anhydride copolymer salt,
Ethylene/acrylic acid copolymer salt, styrene/acrylic acid copolymer salt, styrene/butadiene copolymer emulsion, etc. accounts for 10 to 40% by weight of the total solids, preferably 15% by weight.
It is used in an amount of about 30% by weight.

Furthermore, various auxiliary agents can be added to the coating liquid.
For example, dispersants such as sodium dioctyl sulfosuccinate, sodium dodecylbenzenesulfonate, sodium lauryl alcohol sulfate, alginates, fatty acid metal salts, ultraviolet absorbers such as benzophenone and triazole, and other antifoaming agents. , fluorescent dyes, colored dyes, and the like. If necessary, lubricants such as zinc stearate, calcium stearate, polyethylene wax, carnauba wax, paraffin wax, and ester wax, and sensitizers as described below can also be used in combination. For example, caproic acid amide, capric acid amide, palmitic acid amide, stearic acid amide, oleic acid amide,
Erucic acid ado, linoleic acid ado, linoleic acid ado, N-methylstearic acid ado, stearic acid anilide, N-methyloleic acid amide, henzanilide, linoleic acid anilide, N-ethylcapric acid amide , N-
Butyl lauric acid amide, N-octadecyl acetamide, N-oleic acid acetate, N-oleylbenzamide, N-stearylcyclohexylamide, polyethylene glycol, 1-benzyloxynaphthalene, 2-penzyloxynaphthalene, 1-hydroxynaphthoene Acid phenyl ester, 1,2-diphenoxyethane, l.

■3 4-diphenoxybutane, 1,2-bis(3-methylphenoxy)ethane, 1.2-bis(4-methoxyphenoxy)ethane, 1-phenoxy-2(4-chlorophenoxy)ethane, ■-phenoxy C2-(4-methoxyphenoxy)ethane, 1-(2-methylphenoxy)-2
-(4-methoxyphenoxy)ethane, dibenzyl terephthalate, dibenzyl oxalate, di(4-methoxyphenoxy)ethane,
4-Methylhensyl Lp-benzyloxybenzoic acid benzyl ester, p-hensylbiphenyl, 1,5-bis(p-methoxyphenoxy)-3oxa-bencune, 1
, 4-bis(2-vinyloxyethoxy)henzen, p
-biphenyl p-tolyl ether, hensyl-p-methylthiophenyl ether, etc. In addition, various pigments other than Sachin White, such as inorganic and organic pigments such as kaolin, clay, talc, calcium carbonate, calcined clay, titanium oxide, diatomaceous earth, fine particulate anhydrous silica, activated clay, and aluminum hydroxide, etc. It can also be added.

4 Paper, plastic film, synthetic paper, etc. are used as the support in the thermosensitive recording material of the present invention.

The coating method for the recording layer is not particularly limited, and it can be formed according to conventionally well-known and commonly used techniques, such as bar coating, air knife coating, rondo blade coating, pure blade coating, short dwell coating, etc. It is formed by coating and drying. In addition, when a plastic film is used as a support, the coating efficiency can be increased by subjecting the surface to a treatment such as corona discharge or electron beam irradiation.

The amount of coating liquid to be applied is not particularly limited, but is usually 2 to 2 g/ryf in terms of dry weight, preferably 3 g/ryf.
The range is approximately 10 g/rd.

The heat-sensitive recording material of the present invention is provided with an overcoat layer containing polyvinyl alcohol on the heat-sensitive recording layer as described above, and examples of the polyvinyl alcohol include the following.

Completely saponified or partially saponified polyvinyl alcohol, acetoacetyl-modified polyvinyl alcohol, carboxyl-modified polyvinyl alcohol, sulfonic acid-modified polyvinyl alcohol, olefin-modified polyvinyl alcohol,
Nitrile it polyvinyl alcohol, amide modified polyvinyl alcohol, pyrrolidone modified polyvinyl alcohol, silicon modified polyvinyl alcohol, etc. Among these polyvinyl alcohols, an overcoat layer using silicon-modified polyvinyl alcohol is more preferable because it exhibits particularly excellent properties such as oil resistance and plasticizer resistance. In addition, 2
Of course, it is also possible to use more than one type of polyvinyl alcohol in combination, or to use other water-soluble resins and aqueous emulsions to the extent that the desired effects of the present invention are not inhibited. The coating liquid for the overcoat layer contains various auxiliary agents, as well as the heat-sensitive layer paint.
For example, dispersants, ultraviolet absorbers, antifoaming agents, fluorescent dyes, coloring dyes, etc. can also be added.

In addition, if necessary, lubricants such as zinc stearate, calcium stearate, polyethylene wax, carnauba wax, kaolin, clay, talc, =16 calcium carbonate, calcined clay, titanium oxide, diatomaceous earth, fine particulate anhydrous silica, activated clay, water Inorganic pigments such as aluminum oxide and organic pigments can also be added.

Further, in order to further improve the water resistance and plasticizer resistance of the overcoat layer, a curing agent may be added to the paint forming the overcoat layer. Such curing agents include glyoxal, methylolmeladan, potassium persulfate,
Examples include ammonium persulfate, sodium persulfate, ferric chloride, magnesium chloride, boric acid, fragrant bread, and ammonium chloride.

The coating solution for forming the overcoat layer is generally prepared as an aqueous coating solution, and if necessary, it is thoroughly mixed using a mixing/stirring machine such as a mixer, attritor, ball 5, or roller. After being dispersed, it is coated onto the heat-sensitive recording layer using various known coating devices and dried. After coating, the overcoat layer can also be cured by irradiation with ultraviolet rays or electron beams.

The coating amount of the coating liquid forming the overcoat layer is not particularly limited, but is 0.1 g/rr? If it is less than 20 g/rrf, the desired effect of the present invention cannot be sufficiently obtained, and if it exceeds 20 g/rrf, the recording sensitivity of the heat-sensitive recording medium may be significantly reduced.
~20 g/rd, preferably 0.5-10 g/n
(Adjusted within a certain range.

In addition, if necessary, super calender treatment is applied after coating the heat-sensitive recording layer or overcoat layer to improve image quality.
It is also possible to improve recording density.

Furthermore, when base paper is used as a support, recording density and sensitivity can be increased by providing an undercoat layer consisting of an adhesive and a pigment, and providing a heat-sensitive recording layer thereon. Furthermore, in order to eliminate the influence of oil, plasticizer, etc. from the back surface, a back barrier layer made of adhesive and pigment can be provided on the back surface of the recording medium. As adhesives and pigments used in these undercoat layers and back barrier layers, those used in the heat-sensitive layer described above can be used.

Furthermore, various known techniques in the field of heat-sensitive recording material manufacturing may be added as necessary, such as applying an adhesive treatment to the back surface of the recording material and processing it into an adhesive tape.

"Example" The present invention will be described in more detail with reference to Examples below, but the present invention is of course not limited to these.

Further, unless otherwise specified, parts and percentages in the examples indicate parts by weight and percentages by weight, respectively.

Example 1 ■ Preparation of liquid A 3-(N-ethyl-N-isoamyl))6-methyl-7-phenylaminofluorane 40 parts 1.2-bis(3-methylphenoxy)ethane 100 parts Methyl cellulose 5% aqueous solution 50 parts water
150 parts of this composition was ground with a sand grinder until the average particle size was 2 μm.

■ Solution B Preparation 9 4-Hydroxyphenyl-4'-isopropoxyphenylsulfone 100 parts Methylcellulose 5% aqueous solution 30 parts Water
150 parts of this composition was ground with a sand grinder until the average particle size was 2 μm.

■ Formation of recording layer 340 parts of liquid A, 280 parts of liquid B, 10% oxidized starch aqueous solution 2
50 parts of a 27% aqueous dispersion of Sachin White (trade name: 5W-B, manufactured by Shiraishi Calcium Co., Ltd.) were mixed and stirred to prepare a coating liquid. The resulting coating liquid was applied as a support onto a base paper weighing 46 g per square meter so that the coated amount after drying was 4.5 g/rd, and dried to obtain a heat-sensitive recording material.

■ Formation of overcoat layer After the heat-sensitive layer has been formed, a coating liquid having the following composition is applied to the heat-sensitive recording material so that the coating amount after drying is 3 g/bo, dried, and further coated with a super calender. A heat-sensitive recording material having an overcoat layer was obtained by smoothing treatment.

0 Polyvinyl Alcohol C Product Name: P V A l 1
7. 10% aqueous solution of kaolin (manufactured by Kuraray) 500 parts 60% aqueous dispersion of kaolin 80 parts Zinc stearate 3
0% dispersion (product name: Hydrin Z-7, manufactured by Chukyo Yushi Co., Ltd.) 7 parts 40% aqueous solution of glyoxal 1 part wetting agent (product name: Rapizol B-80, manufactured by NOF Corporation)
0.1 parts Example 2 A thermosensitive recording material was obtained in the same manner as in Example 1, except that a coating liquid having the following composition was applied as an overcoat layer and dried.

Acetoacetyl modified polyvinyl alcohol (Product name: Z
-200, manufactured by Nippon Gosei Kagaku Co., Ltd.) 10% aqueous solution
500 parts 60% aqueous dispersion of kaolin 80 parts 30% dispersion of zinc stearate (
Product name: Hydrin Z-7, manufactured by Middle East Yushi Co., Ltd.) 7
1 part 40% aqueous solution of glyoxal 1 part Wetting agent (trade name: Ravisol B-80, manufactured by NOF 1 Jyusha Co., Ltd.) 0.1 part Example 3 As an overcoat layer, a coating liquid having the following composition was applied and dried. A thermosensitive recording material was obtained in the same manner as in Example 1.

Silicon-modified polyvinyl alcohol (product name: R2105,
417 parts of a 12% aqueous solution of kaolin (manufactured by Kuraray) 80 parts of a 60% aqueous dispersion of kaolin 30% of zinc stearate
7. Manufactured by Middle East Oil Co., Ltd.) 7 parts glyoxal 40
% aqueous solution 1 part wetting agent (trade name Niupizol B
-80, manufactured by NOF Corporation) 0.1 part Example 4 A thermosensitive recording material was obtained in the same manner as in Example 1, except that a coating liquid having the following composition was applied as an overcoat layer and dried.

Silicon-modified polyvinyl alcohol (product name: R2105,
417 parts Aluminum hydroxide (product name: HALi2, manufactured by Showa Kinzoku Co., Ltd.) 48 parts 30% dispersion of zinc stearate (product name: Hydrin Z-7, manufactured by Chukyo Yushi Co., Ltd.) 7 40% aqueous solution of glyoxal
1 part Wetting agent (trade name: Rapizol B-80, manufactured by NOF Corporation) 0.1 part Example 5 In the preparation of liquid A of Example 4, 3-(N-ethyl-N-
A thermosensitive recording material was obtained in the same manner as in Example 4, except that 3-dibutylamino-6-methyl-7-phenylaminofluoran was used instead of 3-dibutylamino-6-methyl-7-phenylaminofluoran.

Example 6 Formation of undercoat layer A coating solution having the following composition was applied to a base paper weighing 46 g per square meter so that the coating amount after drying was 8.5 g/rrr, and dried to form a support having an undercoat layer. did.

3 Calcined clay (trade name: Ansilex) 100 parts Styrene-butadiene copolymer latex (50% concentration) 14 parts 10% dispersion of polyvinyl alcohol 30 parts Water
A heat-sensitive recording material was obtained in the same manner as in Example 5 except that 200 parts of the above support was used.

Comparative Example 1 A heat-sensitive recording material was obtained in the same manner as in Example 1, except that the satin white in the heat-sensitive recording layer of Example 1 was replaced with heavy calcium carbonate.

Comparative Example 2 A heat-sensitive recording material was obtained in the same manner as in Example 1, except that the satin white in the heat-sensitive recording layer of Example 1 was replaced with kaolin.

Comparative Example 3 A thermosensitive recording material was obtained in the same manner as in Comparative Example 1, except that the overcoat coating liquid in Example 3 was used.

4 Comparative Example 4 A heat-sensitive recording material was obtained in the same manner as in Example 1, except that a coating liquid having the following composition was used as the overcoat coating liquid.

15% aqueous solution of etherified starch 333 parts 60% aqueous dispersion of kaolin 80 parts 30% dispersion of zinc stearate (trade name: Hydrin Z-7, manufactured by Middle East Yushi Co., Ltd.) 7 parts 40% aqueous solution of glyoxal
1 part Pizol 13-80 (manufactured by Nihon Yushi Co., Ltd.) 0
．． Using 1 part of the 10 types of heat-sensitive recording materials thus obtained,
It was recorded using PANAFAXIIF-5B and the following evaluations were performed, and the results are shown in Table 1.

"Running performance (sticking characteristics)" Evaluation was made based on the running performance when recording with PANAFAX U F-5E and the noise during recording.

"Recorded Density" The maximum density of the obtained recorded image was measured with a Macbeth densitometer (manufactured by Macbeth, Model RD-100R).

"Solvent Resistance" 5 Methyl ethyl ketone was dropped, and the fading resistance of the recorded image was visually evaluated.

"Oil resistance" Salad oil was dropped onto the recorded image, left indoors for one day, and its fading resistance was visually evaluated.

"Plasticizer Resistance" A vinyl chloride film containing a plasticizer was layered on the recorded image and left indoors for 3 days, and its fading resistance was visually evaluated.

The evaluation criteria for running properties, solvent resistance, oil resistance, and plasticizer resistance were as follows.

“Evaluation criteria” ◎−−−−−−−−−−−−−○−m−−−−−・
−11−−−△−1−−−・−−−m−− It was a heat-sensitive recording material with excellent image stability against oils, plasticizers, etc., as well as excellent recording density and runnability.

=26 Table 1 27

Claims (2)

[Claims] (1) A heat-sensitive recording material in which a recording layer containing at least a color former and a color former that causes the color former to develop color when heated, and an overcoat layer are sequentially provided on a support, and the recording layer contains Sachin White. 1. A heat-sensitive recording material characterized in that the overcoat layer contains polyvinyl alcohol. (2) The heat-sensitive recording material according to claim 1, wherein the polyvinyl alcohol in the overcoat layer is a modified polyvinyl alcohol containing silicon atoms in the molecule.