JP3300795B2 - Thermal recording medium - 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 high gloss and little deterioration in glossiness.

[0002]

2. Description of the Related Art Conventionally, a thermosensitive recording method in which a color image is obtained by contacting both color forming substances by heat utilizing a color reaction between a color forming agent and a color forming agent which forms a color upon contact with the color forming agent. The body is well known. Such a thermosensitive recording medium is relatively inexpensive,
Further, since the recording device is compact and maintenance is relatively easy, it is used not only as a recording medium for facsimile machines and various computers, but also in a wide range of fields such as heat-sensitive labels. In recent years, with the diversification of uses of the heat-sensitive recording medium, development of a heat-sensitive recording medium having strong gloss has been demanded in order to enhance the aesthetic appearance and increase the commercial value. As a method for obtaining such a thermosensitive recording medium, Japanese Patent Application Laid-Open No. 62-279980 discloses a thermosensitive recording method in which an overcoat layer mainly composed of an electron beam curable resin or an ultraviolet curable resin is provided on an intermediate layer mainly composed of a water-soluble resin. Although the body is described, new disadvantages such as a decrease in glossiness under high humidity conditions have been found, and improvements thereof have been demanded.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a thermosensitive recording medium which has a particularly high gloss and has a small decrease in gloss even when exposed to high humidity conditions.

[0004]

Means for Solving the Problems The present inventors have made intensive studies on solving the above-mentioned drawbacks. As a result, a heat-sensitive recording layer containing a color former and a color former, a silyl group-modified polyvinyl alcohol, When the thermosensitive recording medium is constituted by sequentially providing an intermediate layer containing kaolin and / or aluminum hydroxide as a main component and an overcoat layer containing an electron beam-curable resin as a main component and cured by irradiation with an electron beam , It has been found that the following problems can be achieved, and the present invention has been completed.

[0005]

According to the present invention, a heat-sensitive recording layer containing a color former and a color former, an intermediate layer containing silyl group-modified polyvinyl alcohol and kaolin and / or aluminum hydroxide as main components, and electron beam curing are provided on a support. In a thermosensitive recording medium provided with an overcoat layer containing a conductive resin as a main component in order, the ratio of the silyl group-modified polyvinyl alcohol and kaolin and / or aluminum hydroxide used in the intermediate layer is not particularly limited, but the silyl group-modified is particularly preferred. 6 kaolin and / or aluminum hydroxide to polyvinyl alcohol
It is desirable to adjust in the range of 0 to 150% by weight. When the use ratio of the specific pigment exceeds 150% by weight, the gloss after forming the overcoat layer is reduced, and when the pigment is less than 60% by weight, the gloss may be reduced when exposed to high humidity conditions. .

The silyl group-modified polyvinyl alcohol used for the intermediate layer in the present invention is not particularly limited, but a polymerization degree of 400 to 2800, a saponification degree of 70 or more, and a monomer having silicon such as organosiloxane of 0.1 to 0.1 are preferred. Those having 5 mol% are preferred. The average particle diameter of kaolin and aluminum hydroxide is preferably 3 μm or less, more preferably 2 μm or less. In the present invention, the combination of the color former and the color former contained in the heat-sensitive recording layer is not particularly limited, and any combination may be used as long as the two are brought into contact by heat to cause a color reaction. Examples thereof include a combination of a colorless or pale-colored basic dye and an inorganic or organic acidic substance, and a combination of a higher fatty acid metal salt such as ferric stearate and a phenol such as gallic acid. However, a combination of a basic dye and an acidic substance is particularly preferably used in terms of recording characteristics.

Various types of colorless or light-colored basic dyes are known, and examples thereof include the following. 3,3
-Bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3,3-bis (1,2-dimethylindol-3-yl) -5-dimethylaminophthalide,
Triallylmethane dyes such as 3,3-bis (1,2-dimethylindol-3-yl) -6-dimethylaminophthalide;

Diphenylmethane dyes such as 4,4'-bis-dimethylaminobenzhydryl benzyl ether, N-halophenyl-leuco auramine, N-2,4,5-trichlorophenyl leuco auramine, benzoyl leucomethylene blue, p Thiazine dyes such as nitrobenzoyl leucomethylene blue, 3-methyl-spiro-
Spiro dyes such as dinaphthopyran and 3-propyl-spiro-dibenzopyran; lactam dyes such as rhodamine-B-anilinolactam, rhodamine (p-nitroanilino) lactam and rhodamine (o-chloroanilino) lactam;

3-dimethylamino-7-methoxyfluoran, 3-diethylamino-6-methoxyfluoran,
3-diethylamino-6-methyl-7-chlorofluoran, 3-diethylamino-6,7-dimethylfluoran, 3- (N-ethyl-p-toluidino) -7-methylfluoran, 3-diethylamino-7- N-acetyl-
N-methylaminofluoran, 3-diethylamino-7
-N-methylaminofluoran, 3-diethylamino-
7-N-diethylaminofluoran, 3- (N-ethyl-p-toluidino) -6-methyl-7-phenylaminofluoran, 3- (N-ethyl-p-toluidino) -6
-Methyl-7- (p-toluidino) fluoran, 3-diethylamino-6-methyl-7-phenylaminofluoran, 3- (N-ethyl-N-isoamylamino) -6
-Methyl-7-phenylaminofluoran, 3- (N-
Cyclohexyl-N-methylamino) -6-methyl-7
-Phenylaminofluoran, 3-diethylamino-6
-Methyl-7-xylidinofluoran, 3-diethylamino-7- (o-chlorophenylamino) fluoran,
3-dibutylamino-7- (o-chlorophenylamino) fluoran, 3-pyrrolidino-6-methyl-7-p
-Fluoran dyes such as butylphenylamino fluoran and the like.

Various inorganic or organic acidic substances which are colored upon contact with a basic colorless dye are also known.
For example, activated clay, acid clay, attapulgite, bentonite, colloidal silica, inorganic acid substances such as aluminum silicate 4-hydroxydiphenoxide, β-naphthol, 2,
2'-methylenebis (4-methyl-6-tert-butylphenol), 4,4'-isopropylidenebis (2-te
rt-butylphenol), 4,4'-sec-butylidenediphenol, 4-phenylphenol, 4,4'-isopropylidenediphenol (bisphenol A),
2,2'-methylenebis (4-chlorophenol),
Hydroquinone, 4,4'-dihydroxydiphenylsulfone, 2,4'-dihydroxydiphenylsulfone,
Phenolic compounds such as 4,4'-cyclohexylidene diphenol, benzyl 4-hydroxybenzoate, dimethyl 4-hydroxyphthalate, hydroquinone monobenzyl ether, novolak phenolic resin, and phenolic polymer;

P-tert-butylbenzoic acid, 3-cyclohexyl-4-hydroxybenzoic acid, 3,5-dimethyl-
4-hydroxybenzoic acid, salicylic acid, 3-isopropylsalicylic acid, 3-tert-butylsalicylic acid, 3-benzylsalicylic acid, 3- (α-methylbenzyl) salicylic acid, 3-chloro-5- (α-methylbenzyl) salicylic acid, , 5-Di-tert-butylsalicylic acid, 3-phenyl-5- (α, α-dimethylbenzyl) salicylic acid,
Aromatic carboxylic acids such as 3,5-di-α-methylbenzylsalicylic acid, and their phenolic compounds, aromatic carboxylic acids and polyvalent compounds such as zinc, magnesium, aluminum, calcium, titanium, manganese, tin and nickel Examples thereof include organic acidic substances such as salts with metals.

In the heat-sensitive recording material of the present invention, the ratio of the color former to the color former in the recording layer is appropriately selected according to the type of the color former or the color former to be used. When a basic dye and an acidic substance are used, it is generally 100 to 70% by weight, preferably 100% by weight, based on the basic dye.
About 400% by weight of acidic substances are used.

The preparation of a coating liquid containing these substances is generally carried out by dispersing the color former and the color former together or separately using a stirring / pulverizer such as a ball mill, an attritor or a sand mill using water as a dispersion medium. Prepared.

In such a coating liquid, for example, starches, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, gelatin, casein, gum arabic, polyvinyl alcohol, diisobutylene / maleic anhydride copolymer salt, styrene / maleic anhydride Acid copolymer salt, ethylene / acrylic acid copolymer salt,
A styrene / acrylic acid copolymer salt, a styrene / butadiene copolymer emulsion or the like is used in an amount of about 10 to 40% by weight, preferably about 15 to 30% by weight of the total solid.

Furthermore, various auxiliaries can be added to the coating liquid, such as sodium dioctyl sulfosuccinate, sodium dodecylbenzene sulfonate, sodium lauryl alcohol sulfate, sodium alginate, metal salts of fatty acids, etc. A benzophenone-based or triazole-based ultraviolet absorber, an antifoaming agent, a fluorescent dye, a coloring dye, a storage stability improving agent, and the like are added as necessary.

Lubricants such as zinc stearate, calcium stearate, polyethylene wax, carnauba wax, paraffin wax, ester wax, etc.
Inorganic pigments such as kaolin, clay, talc, calcium carbonate, calcined clay, titanium oxide, diatomaceous earth, fine anhydrous silica, activated clay, etc., and stearamide, stearic methylenebisamide, oleic amide, palmitic amide, and perfume oleic acid Amide, coconut fatty acid amide,
Di-p-methylbenzyl oxalate, 1,2-di (4-
Sensitizers such as phenoxy) ethane, p-benzylbiphenyl and 2-naphthylbenzyl ether can also be added.

Examples of the support include papers such as high-quality paper, art paper, and coated paper; plastic films such as polyethylene, polyester, polyvinyl chloride, polystyrene, and nylon; and sheets obtained by laminating plastic on paper; Synthetic paper manufactured by a film method or a fiber method is used.

The method for applying the coating liquid for the recording layer is not particularly limited. For example, a bar coater, an air knife coater, a rod blade coater,
Coating and drying are performed by a suitable coating machine such as a pure blade coater or a short dwell coater. When a plastic film is used as the support, the surface can be subjected to a treatment such as corona discharge or electron beam irradiation to increase the coating efficiency. The amount of the coating liquid is not particularly limited, and is usually ² to 12 g / m ² , preferably 3 to 12 g / m ² in terms of dry weight.
It is adjusted in the range of about 10 to 10 g / m ² .

In the heat-sensitive recording material of the present invention, an intermediate layer containing silyl group-modified polyvinyl alcohol and kaolin and / or aluminum hydroxide as main components is provided on the heat-sensitive recording layer thus formed. In addition to the silyl group-modified polyvinyl alcohol, other water-soluble resins or water-dispersible resins can be used in combination as long as the desired effect is not impaired. For example, completely or partially saponified polyvinyl alcohol, acetoacetylated polyvinyl alcohol, carboxy-modified polyvinyl alcohol, amide-modified polyvinyl alcohol obtained by saponifying a copolymer of vinyl acetate with amides such as acrylamide and methacrylamide, acetic acid Polyvinyl alcohols such as pyrrolidone-modified polyvinyl alcohol obtained by saponifying a copolymer of vinyl and N-vinylpyrrolidone, cellulose derivatives such as methylcellulose, ethylcellulose, hydroxyethylcellulose and carboxymethylcellulose, casein, gum arabic, oxidized starch, ether Starches, such as esterified starch, dialdehyde starch, esterified starch,
Styrene-butadiene copolymer emulsion, vinyl acetate-vinyl chloride-ethylene copolymer emulsion, methacrylate-butadiene copolymer emulsion and the like.

Further, a curing agent such as glyoxal, methylol melamine, potassium persulfate, ammonium persulfate, sodium persulfate, ferric chloride, magnesium chloride, boric acid, ammonium chloride, etc. is added to the coating solution for forming the intermediate layer. Lubricant such as zinc stearate, calcium stearate, stearic acid amide, polyethylene wax, carnauba wax, paraffin wax, ester wax, etc., sodium dioctyl sulfosuccinate, sodium dodecylbenzene sulfonate, sodium lauryl alcohol sulfate as required Surfactants such as sodium salts, alginates, and fatty acid metal salts, and various assistants such as benzophenone-based and triazole-based ultraviolet absorbers, defoamers, fluorescent dyes, and coloring dyes can also be appropriately added.

The coating liquid for forming the intermediate layer is generally prepared as an aqueous coating liquid, and if necessary, sufficiently mixed and dispersed by a mixing stirrer such as a mixer, an attritor, a ball mill, a roll mill, etc. It is applied on the heat-sensitive recording layer by a coating device. After the application, curing and drying may be performed by irradiating ultraviolet rays or electron beams. When a curing agent is used in combination, the curing agent can be applied not only in the coating liquid for forming the intermediate layer but also separately from the coating liquid for forming the intermediate layer. There is an advantage that there is no need to worry about life and a strong curing agent can be selected.

The coating amount of the coating solution for forming the intermediate layer is not particularly limited, but if it is less than 0.1 g / m ² , the desired effects of the present invention cannot be sufficiently obtained.
If the amount exceeds g / m ² , the recording sensitivity of the thermosensitive recording medium may be significantly reduced.
/ M ² , preferably in the range of about 0.5 to 10 g / m ² .

Further, if necessary, a similar coating layer may be provided on the back side of the thermosensitive recording medium to further improve the storability. Further, various known techniques in the field of heat-sensitive recording materials can be added as necessary, such as providing an undercoat layer on the support, applying a pressure-sensitive adhesive treatment to the back surface of the recording material, and processing the pressure-sensitive adhesive label.

By increasing the smoothness of the surface of the intermediate layer, a recording medium having a high recording density and gloss can be obtained. When the body is a plastic film or synthetic paper, the time is 500 seconds or more, more preferably 1600 seconds or more.
It is desirable to adjust it to 0 seconds or more, more preferably 300 seconds or more.

In the thermosensitive recording medium of the present invention, an overcoat layer containing an electron beam-curable resin as a main component is provided on the intermediate layer thus formed. The electron beam-curable resin forming the overcoat layer is as follows. The listed prepolymers and monomers are exemplified.

(A) aliphatic, alicyclic, and araliphatic poly (meth) acrylates of dihydric to hexavalent polyhydric alcohols and polyalkylene glycols; (b) aliphatic, alicyclic, araliphatic and aromatic Poly (meth) polyhydric alcohol in the form of alkylene oxide added to polyhydric alcohol of group 2 to 6
Acrylate; (c) Poly (meth) acryloyloxyalkyl phosphate ester; (d) Polyester poly (meth)
Acrylate; (e) Epoxy poly (meth) acrylate; (f) Polyurethane poly (meth) acrylate; (g)
(H) polysiloxane poly (meth) acrylate; (i) a vinyl- or diene-based low polymer having a (meth) acryloyloxy group in a side chain and / or a terminal; a) Prepolymers such as the oligoester (meth) acrylate modified products described in (a) to (i).

Examples of the monomer include (a) a carboxyl group-containing monomer represented by an ethylenically unsaturated mono- or polycarboxylic acid and a carboxylate-containing monomer such as an alkali metal salt, an ammonium salt or an amine salt thereof. Monomer;
(b) amide group-containing monomers represented by vinyl lactams such as ethylenically unsaturated (meth) acrylamide or alkyl-substituted (meth) acrylamide, N-vinylpyrrolidone; (c) aliphatic or aromatic vinyl sulfone Sulfonic acid group-containing monomers represented by acids and their sulfonic acid group-containing monomers such as alkali metal salts, ammonium salts and amine salts; (d) hydroxyl group-containing monomers represented by ethylenically unsaturated ethers and the like; (E) amino group-containing monomers such as dimethylaminoethyl (meth) acrylate-2-vinylpyridine;

(F) a quaternary ammonium base-containing monomer;
(g) alkyl esters of ethylenically unsaturated carboxylic acids;
(h) monomers containing nitrile groups such as (meth) acrylonitrile; (i) styrene; (j) esters of ethylenically unsaturated alcohols such as vinyl acetate and (meth) allyl acetate; (k) containing active hydrogen Mono (meth) acrylates of alkylene oxide addition polymers of compounds; (l) ester group-containing bifunctional monomers represented by diesters of polybasic acids and unsaturated alcohols; (m) compounds containing active hydrogen A bifunctional monomer consisting of a diester of an alkylene oxide addition polymer and (meth) acrylic acid;

(N) Bisacrylamide such as N, N-methylenebisacrylamide; (o) Bifunctional monomer such as divinylbenzene, divinylethylene glycol, divinylsulfone, divinylether, divinylketone; (p) polycarboxylic acid (Q) a polyfunctional monomer comprising a polyester of an alkylene oxide addition polymer of a compound containing active hydrogen and (meth) acrylic acid; And (r) polyfunctional unsaturated monomers such as trivinylbenzene. In addition, two or more kinds of the above-mentioned electron beam curable resins may be used in combination.

In the resin component, in addition to the above prepolymers and monomers, calcium carbonate, barium carbonate, zinc carbonate, zinc oxide, aluminum oxide, titanium dioxide, silicon dioxide, aluminum hydroxide, barium sulfate, zinc sulfate, Inorganic pigments such as talc, kaolin, clay, calcined clay, and colloidal silica, and pigments obtained by treating these inorganic pigments with organic acids, styrene microballs, nylon powder, polyethylene powder, urea / formalin resin powder, cellulose acetate powder, poly Organic pigments such as methyl methacrylate powder, fluorine resin powder, epoxy resin powder, benzoguanamine resin powder, raw starch granules, non-electron beam curable resin, defoamer, leveling agent,
Additives such as a lubricant, a surfactant, a plasticizer, and an ultraviolet absorber can be appropriately added.

Further, a fluorescent dye, a coloring dye, a fluorescent pigment,
It is also possible to increase the coloring effect of the colored layer by adding a coloring pigment, etc., and by adjusting the type and blending ratio of various additives, a thermosensitive recording material having a wide range of surface properties from matte to high gloss Can be formed. In addition,
Examples of the non-electron beam curable resin include an acrylic resin, a silicone resin, an alkyd resin, a fluorine resin, a butyral resin, and the like.

The above-mentioned resin component is sufficiently mixed by a suitable mixing stirrer such as a mixer, and then applied on the intermediate layer by various known methods. If necessary, the resin component is heated. The viscosity can also be adjusted. The amount of coating is not necessarily limited, but may be 0.1 g / m
^If it is less than ² , the desired effect of the present invention cannot be sufficiently expected, and 1
Since the recording sensitivity of the recording material obtained exceeds the 0 g / m ² may be decreased, 0.1~20g / m ^2, and more preferably is adjusted from 1 to 5 g / m ^2.

The amount of the irradiated electron beam is 0.1 to 15 Mrad,
More preferably, the range is about 0.5 to 10 Mrad. By the way, if it is less than 0.1 Mrad, the resin component cannot be sufficiently cured, and excessive electron beam irradiation exceeding 15 Mrad may cause coloration or discoloration of the thermosensitive recording medium. In the case of paper, the paper strength may be reduced. The electron beam irradiation method may be, for example, a scanning method, a curtain beam method, a broad beam method, or the like.
About 100 to 300 KV is appropriate.

The heat-sensitive recording material of the present invention having the overcoat layer thus obtained can be further subjected to a smoothing treatment using a super calender or the like to further improve the recording density and the recording density unevenness.

[0035]

The present invention will be described in more detail with reference to the following Examples, but it should be understood that the present invention is by no means restricted thereto. In addition, unless otherwise specified, parts and% in the examples indicate parts by weight and% by weight, respectively.

Example 1 Formation of undercoat layer Fired clay [trade name: Ansilex, manufactured by EMC] 1
00 parts, 15 parts of styrene-butadiene copolymer latex (solid content: 50%), 1 part of polyvinyl alcohol
0% aqueous solution of 30 parts, and consists of 200 parts of water mixed, stirred was coated amount after drying on a high-quality paper coating liquid basis weight 50 g / m ² is applied and dried so that 8 g / m ² obtained by To form an undercoat layer.

Solution A Preparation A composition consisting of 10 parts of 3- (N-ethyl-N-isoamylamino) -6-methyl-7-phenylaminofluoran, 5 parts of a 5% aqueous solution of methylcellulose, and 30 parts of water is sand-milled. It was pulverized until the average particle size became 1 μm.

Solution B Preparation 20 parts of 4-hydroxy-4′-isopropoxydiphenyl sulfone, 5 parts of a 5% aqueous solution of methylcellulose, and 55 parts of water
Part by weight of a composition comprising
m.

Formation of heat-sensitive recording layer 45 parts of solution A, 80 parts of solution B, 50% aqueous 20% starch oxide solution
And 10 parts of water were mixed and stirred, and 50 g of the coating liquid was prepared.
/ M ² base paper was dried so that the coating amount after drying was 6 g / m ² to form a heat-sensitive recording layer.

Formation of Intermediate Layer On the obtained heat-sensitive recording layer, 1000 parts of a 10% aqueous solution of silyl group-modified polyvinyl alcohol [trade name: R1130, manufactured by Kuraray Co., Ltd.], kaolin [trade name: UW-90, manufactured by Engelhart Co., Ltd.] An intermediate layer coating solution composed of 100 parts and 400 parts of water is applied and dried so that the applied amount after drying is 4 g / m ^2, and is further subjected to a smoothing treatment with a super calender to have a Beck smoothness of 500 seconds. Formed an intermediate layer

Formation of Overcoat Layer An electron beam curable resin [trade name: GRANDIC] is formed on the intermediate layer.
EB 0227, manufactured by Dainippon Ink and Chemicals, Inc.] so that the dry coating amount is 4 g / m ^2, and then an electron curtain type electron beam irradiation device [CB: 150 type, ES
(Manufactured by I Company) at an irradiation dose of 1.5 Mrad to cure the resin component, thereby obtaining a thermosensitive recording medium having an overcoat layer.

Example 2 A heat-sensitive material was prepared in the same manner as in Example 1, except that aluminum hydroxide (trade name: Heidilite H42, manufactured by Showa Denko KK) was used instead of kaolin in forming the intermediate layer of Example 1. A recording was obtained.

Example 3 In the formation of the intermediate layer of Example 1, instead of 1000 parts of a 10% aqueous solution of a silyl group-modified polyvinyl alcohol, 850 of a 10% aqueous solution of a silyl group-modified polyvinyl alcohol was used.
Resin obtained by grafting acrylamide or acrylic acid to a part of polyvinyl alcohol and a commercial product [trade name: Papyrrole F73]
6, manufactured by Showa Denko KK], and a thermosensitive recording medium was obtained in the same manner as in Example 1 except that 100 parts of a 15% aqueous solution was used.

COMPARATIVE EXAMPLE 1 The procedure of Example 1 was repeated except that a 10% aqueous solution of completely saponified polyvinyl alcohol (trade name: PVA117, manufactured by Kuraray Co., Ltd.) was used instead of the 10% aqueous solution of silyl group-modified polyvinyl alcohol. Was obtained in the same manner as in Example 1.

Comparative Example 2 In forming the intermediate layer in Example 1, a 10% aqueous solution of modified starch (trade name: Petrocoat C-8, manufactured by Nichiren Chemical Co., Ltd.) was used instead of the 10% aqueous solution of silyl group-modified polyvinyl alcohol. A thermosensitive recording medium was obtained in the same manner as in Example 1 except that

Comparative Example 3 Thermal recording was performed in the same manner as in Example 1 except that calcium carbonate (trade name: Softon 1500, manufactured by Bihoku Powder Chemical Co., Ltd.) was used instead of kaolin in forming the intermediate layer of Example 1. I got a body. Comparative Example 4 In the formation of the intermediate layer of Example 1, the applied amount after drying a 10% aqueous solution of a silyl group-modified polyvinyl alcohol was 2 g.
/ M ^2, and a heat-sensitive recording material was obtained in the same manner as in Example 1 except that the coating was dried.

The thermal recording medium thus obtained was subjected to the following quality tests, and the results are shown in Table 1.

[Recording Density] Thermal Sensitivity Evaluation Machine [Okura Electric Co., Ltd.
TH-PMD type, applied energy 0.3 mJ / do
t, an applied pulse width of 1.4 ms], a recording density of a recording image obtained by recording with a Macbeth densitometer [RD, manufactured by Macbeth Co., Ltd.
-914 type] Measured in visual mode.

[Gloss] Untreated, 40 ° C., 90%
The glossiness of the surface of the thermosensitive recording medium after standing for 24 hours under the condition of RH was measured using a goniophotometer (a gloss meter G, manufactured by Murakami Color Research Laboratory).
M-3D) at an incident angle of 60 degrees. (The higher the value, the higher the gloss.)

[0050]

[Table 1]

[0051]

As is clear from the results shown in Table 1, the heat-sensitive recording material of the present invention is a heat-sensitive recording material having a high surface gloss and a small decrease in gloss even when exposed to high humidity conditions.

Claims (2)

(57) [Claims] 1. A heat-sensitive recording layer containing a color former and a color former on a support, an intermediate layer containing silyl group-modified polyvinyl alcohol and kaolin and / or aluminum hydroxide as main components, and an electron beam-curable resin. With electron beam
A heat-sensitive recording material, wherein an overcoat layer cured by irradiation is sequentially provided. 2. A method according to claim 1, wherein the content of kaolin and / or aluminum hydroxide is at least 60 with respect to the silyl group-modified polyvinyl alcohol.
2. The thermosensitive recording medium according to claim 1, wherein the content is in the range of 150% by weight.