JP2717756B2 - 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 medium having excellent printability for water-based ink on its surface, and more particularly to papers such as tickets and pass tickets, cards such as prepaid cards, and POS (Point of Point). The present invention relates to a heat-sensitive recording medium that can be applied to labels such as sales.

[0002]

2. Description of the Related Art In general, a heat-sensitive recording medium having a heat-sensitive recording layer mainly composed of a colorless or light-colored leuco dye and a color developer which reacts with the leuco dye when heated to form a color is disclosed in
Published in No. 14035, etc., and widely used. In order to perform recording on the thermosensitive recording medium, a thermal printer or the like having a built-in thermal head is used. Compared with other conventional recording methods, such a thermal recording method has no noise at the time of recording, does not require development and fixing, is maintenance-free, the equipment is relatively inexpensive and compact, and the resulting coloring is obtained. It is widely used as computer output, facsimile, recorder paper for calculators and various measuring machines, and ticket paper for automatic ticket vending machines.

Conventional thermal recording media used for various applications as described above are required to have not only recording characteristics but also storage stability of images such as chemical resistance and water resistance. As disclosed in JP-A-188392 and others, a protective layer is provided on the heat-sensitive recording layer. The composition of such a protective layer is generally a mixture of a water-soluble or water-dispersible polymer compound and various additives such as a pigment. In recent years, there has been a strong demand for printing with a water-based ink on the surface of the protective layer in the label field such as a POS label or in a ticket such as a ticket. In particular, in a ticket, a stamp using a water-based ink is used instead of the conventional scissors. The inspection method is adopted.

However, although the recording properties, chemical resistance, water resistance, etc. of the conventional heat-sensitive recording medium have been sufficiently studied as described above, the printing suitability such as ink absorbency, drying property, fixing property, etc. for aqueous inks is poor. Printability was poor because little was considered. That is, a water-soluble resin such as polyvinyl alcohol conventionally used as a protective layer does not provide sufficient printability for an aqueous ink, and furthermore, in order to improve blocking resistance under high humidity conditions, an emulsion-based resin is used. Since water absorption is suppressed by using a resin or a water-proofing agent to suppress water absorption, printing suitability for water-based ink is adversely affected, which has an adverse effect. Further, by increasing the amount of the pigment added, it is possible to improve the absorbability of the water-based ink. However, there is a problem that the transparency of the protective layer is reduced and the image clarity of the heat-sensitive recording layer is reduced. Would. in this way,
In conventional thermal recording media, the printability of aqueous inks cannot be satisfied, and there is a growing demand for thermal recording media having excellent printability of aqueous inks as well as good recording characteristics and image storability. is there.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has excellent printability for aqueous inks without impairing the recording characteristics and storage stability required for a heat-sensitive recording medium. That is, the present invention provides a heat-sensitive recording medium having ink absorbing, drying and fixing properties on the surface.

[0006]

According to the present invention, there is provided a heat-sensitive recording medium comprising a support and a heat-sensitive recording layer and a protective layer laminated on at least one side thereof, wherein the protective layer is a water-soluble or water-dispersible polymer. A thermosensitive recording medium comprising a compound and at least one mica selected from the compounds represented by the following general formula (1). _{(Na, Li) m Mg n} Li 6-2n-m Si 4 O 10 (F, OH) 2 (1) [ The number in the range of wherein, m is 1/3 to 1, n is 2-8 / 3 Represents]

The mica represented by the general formula (1) used for the protective layer in the present invention includes the following compounds. _{NaMg 2 LiSi 4 O 10 F 2} NaMg 2 LiSi 4 O 10 (OH) 2 NaMg 2.5 Si 4 O 10 F 2 NaMg 2.5 Si 4 O 10 (OH) 2 Na 2/3 Mg 7/3 Li 2/3 Si 4 O ₁₀ F ₂ (vermiculite) Na _2/3 Mg _7/3 Li _2/3 Si ₄ O ₁₀ (OH) ₂ (vermiculite) Na _1/3 Mg _8/3 Li _1/3 Si ₄ O ₁₀ F ₂ (montmorillonite Na _1/3 Mg _8/3 Li _1/3 Si ₄ O ₁₀ (OH) ₂ (montmorillonite) LiMg ₂ LiSi ₄ O ₁₀ F ₂ LiMg ₂ LiSi ₄ O ₁₀ (OH) ₂ Li _2/3 Mg _7/3 Li _2/3 Si ₄ O ₁₀ F ₂ Li _2/3 Mg _7/3 Li _2/3 Si ₄ O ₁₀ (OH) ₂ Li _1/3 Mg _8/3 Li _1/3 Si ₄ O ₁₀ F ₂ Li _{1 / 3} Mg _8/3 Li _1/3 Si ₄ O ₁₀ (OH) ₂

Generally, naturally occurring mica is represented by (K) _m Mg _n Li _6-2n-m Si ₄ O ₁₀ (OH) _{2 wherein} m and n have the same meanings as in formula (1). And has no swelling property. The specific mica represented by the general formula (1) used in the present invention has a structure in which potassium ions of naturally occurring mica are replaced with sodium ions or lithium ions, and has swelling properties in water. In the present invention, the term mica is used to include vermiculite and montmorillonite. The mica used in the present invention is, for example, “M
E-100 "(manufactured by Corp Chemical)," Smectite SWF "(manufactured by Corp Chemical)," Smectite SW "
N "(manufactured by Corp Chemical)
“ME-100” is NaMg ₂ LiSi ₄ O ₁₀ F ₂ ,
“Smectite SWF” is Na _1/3 Mg _8/3 Li _1/3 Si ₄
O ₁₀ F ₂ , “Smectite SWN” is Na _1/3 Mg _8/3 L
It has a composition of i _1/3 Si ₄ O ₁₀ (OH) ₂ .

The protective layer in the present invention comprises at least the mica represented by the general formula (1) and a water-soluble or water-dispersible polymer compound. As such a polymer compound, for example, polyvinyl alcohol, carboxyl-modified polyvinyl alcohol, other modified polyvinyl alcohol, polyvinylpyrrolidone, casein,
Gelatin, oxidized starch, isobutylene-maleic anhydride copolymer resin, diisobutylene-maleic anhydride copolymer resin, styrene-maleic anhydride copolymer resin, carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, polyvinyl acetate, poly ( Meta)
Acrylic resins, vinyl chloride-vinyl acetate copolymer resins, styrene-butadiene copolymer resins, acrylonitrile-butadiene copolymer resins, polyvinyl acetal resins, polyvinyl butyral resins, amide resins, etc. Used mixed. Among these, preferable polymer compounds include carboxyl-modified polyvinyl alcohol, polyvinyl alcohol-based resins such as polyvinyl alcohol, water-soluble polyvinyl acetal resins, polyvinyl pyrrolidone, and the like, from the viewpoints of blendability with mica, printability for aqueous ink, and the like. Is exemplified. In the present invention, in order to obtain excellent water resistance, it is preferable to use a water-resistant agent such as a polyamide epoxy resin, a melamine resin, a melamine formaldehyde resin, a polyamide resin, glyoxal, and chromium ban in combination.

In the present invention, in order to obtain better film properties (barrier properties), chemical resistance, water resistance, etc., a carboxyl-modified polyvinyl alcohol and a polyamide epoxy resin are combined among the above-mentioned polymer compounds and water-resistant agents. It is particularly preferable to use them. Here, the carboxyl-modified polyvinyl alcohol is a polyvinyl alcohol containing one free acid type carboxyl group or a carboxyl group having a form of a metal salt in the molecule. These carboxyl-modified polyvinyl alcohols can be obtained by, for example, saponifying a copolymer of vinyl acetate and (meth) acrylic acid, fumaric acid, maleic acid, itaconic acid, or the like. A polyamide epoxy resin is a compound having a glycidyl group in a molecule obtained by reacting an epichlorohydrin with a polyamide resin obtained by condensation of an alkylpolyamine compound and an alkyldicarboxylic acid, and is, for example, Sparamine A3 manufactured by Toho Chemical Industry.
01 (product name) can be used.

The polyamide epoxy resin as described above functions as a crosslinking agent for carboxyl-modified polyvinyl alcohol. By using a polyamide epoxy resin as the cross-linking agent, the reaction proceeds even at room temperature where cross-linking is difficult with a general cross-linking agent, and good water resistance and coating properties can be imparted to the protective layer. In the case of the thermosensitive recording medium of the present invention, since a high temperature cannot be applied for curing the cross-linking agent, the cross-linking agent used is required to react at room temperature. In that respect, polyamide epoxy resin, when used in combination with carboxyl-modified polyvinyl alcohol,
It is preferably used because it has good room temperature crosslinking properties. The amount of the polyamide epoxy resin added to the protective layer is 5 to 10 parts by weight based on 100 parts by weight of the carboxyl-modified polyvinyl alcohol in a solid content ratio in the protective layer.
0 parts by weight is preferable, and 30 to 80 parts by weight is particularly preferable. When the addition amount of the polyamide epoxy resin is 5 parts by weight or less, not only does it take a long time for the cross-linking reaction, but also the coating properties are insufficient, so that more excellent barrier properties, chemical resistance and water resistance may not be obtained. On the other hand, if the compounding ratio exceeds 100 parts by weight, the epoxy group in the polyamide epoxy resin may react with the leuco dye, causing the heat-sensitive layer to develop color, which is not preferable.

In the protective layer of the thermal recording medium of the present invention, various pigments such as clay, talc, diatomaceous earth, alumina, calcium carbonate, Use calcium sulfate, zeolite, cellulose fine powder, polyethylene fine powder, silicone resin fine powder, phenol resin fine powder, benzoguanamine resin fine powder, etc .; lubricity improvers such as zinc stearate and calcium stearate; fluororesins; silicone grease And the like.

In the protective layer having the composition as described above,
The mixing ratio of mica is 5 to 60% by weight in the total solid content of the layer.
It is particularly preferable that the content is 20 to 50% by weight. Here, if the mixing ratio of mica is less than 5% by weight, sufficient printability with respect to the aqueous ink cannot be obtained.
If the content is more than 10% by weight, the barrier properties of the protective layer may be reduced, and sufficient chemical resistance and water resistance may not be obtained. In the present invention, by forming the protective layer as described above,
Good printability for aqueous inks can be obtained without impairing properties such as film properties, chemical resistance, and water resistance required for the protective layer.

Next, the heat-sensitive recording layer of the present invention will be described. The heat-sensitive recording layer contains a colorless or light-colored leuco dye and a developer for developing the leuco dye as main components. Typical leuco dyes used include crystal violet lactone, 3-diethylamino-7-chlorofluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-cyclohexylamino-6-chlorofluorane, 3-diethylamino-7-dibenzylaminofluoran, 3-pyrrolidino-6-methyl-7-anilinofluoran, 3-piperidino-6-methyl-7-anilinofluoran, 3-cyclohexylmethylamino-6 Methyl-7-anilinofluoran, 3-ethylisoamylamino-6-methyl-7
-Anilinofluoran, 3-diethylamino-7- (о
-Chloroanilino) fluoran, 3-dibutylamino-
7- (о-chloroanilino) fluoran and the like, but are not particularly limited. Further, as the color developer which reacts with the leuco dye to form a color, α-naphthol, β
-Naphthol, 4-t-butylphenol, 4-t-octylphenol, 4-phenylphenol, 2,2-
Bis (p-hydroxyphenyl) propane, 2,2-bis (p-hydroxyphenyl) butane, 4,4′-cyclohexylidenediphenol, 2,2-bis (2,5-
Dibromo-4-hydroxyphenyl) propane, 4,
4′-isopropylidenebis (2-t-butylphenol), 2,2′-methylenebis (4-chlorophenol), 4,4′-thiodiphenol, 4,4′-sulfonyldiphenol, benzoic acid, salicylic acid, Derivatives such as gallic acid include, but are not limited to.

As the binder used for the heat-sensitive recording layer, various water-soluble or water-dispersible polymer compounds are used, and the polymer compound that can be used for the protective layer can be appropriately used. . Furthermore, in the thermosensitive recording layer,
Various heat-fusible substances can be added as needed to improve the recording sensitivity, and various fillers can be added to improve the image quality. Examples of these heat-fusible substances include organic compounds having an appropriate melting point, for example, higher fatty acid amides such as stearamide, beeswax, animal waxes such as shellac wax,
Vegetable waxes such as carnauba wax, mineral waxes such as montan wax, paraffin wax, microcrystalline wax, higher fatty acids, esters of higher fatty acids, aromatic carboxylic acid esters such as dimethyl terephthalate and diphenyl phthalate, alkyl naphthalene derivatives, alkyl diphenyl Derivatives, alkyl terphenyl derivatives and the like are used. Furthermore, in the heat-sensitive recording layer, inorganic and organic pigments as fillers, for example, clay, talc, diatomaceous earth, alumina, calcium carbonate,
By adding calcium sulfate, zeolite, cellulose fine powder, polyethylene fine powder, silicone resin fine powder, phenol resin fine powder, benzoguanamine resin fine powder, etc., the sharpness of a color image can be improved. In addition, various surfactants, defoamers, antioxidants, and ultraviolet absorbers can be added as needed.

The heat-sensitive recording layer in the present invention has the above-mentioned composition, and a coating material comprising the leuco dye, a color developer, a binder and other optional compounds is coated on a support. The coating is a coating liquid which is pulverized by a disperser such as a media type wet disperser, and has a particle size of a leuco dye, a developer, etc. Is 5 μm or less, particularly preferably 3 μm.
It is desirable from the viewpoint of recording characteristics that the thickness be not more than μm.

The support used in the heat-sensitive recording medium of the present invention includes paper, thermoplastic resin sheet, metal foil, metal plate,
Metal deposition sheet, metal fiber sheet, ceramic sheet,
The woven fabric, non-woven fabric, and composites thereof are not particularly limited. In the present invention, in order to form the heat-sensitive recording layer and the protective layer on the support, a coating solution obtained by dispersing or dissolving a material for forming each of the above-mentioned layers is subjected to a roll coating method, a blade coating method, and a spray coating method. It is performed by applying and drying by a method such as an air knife coating method and a rod bar coating method. The preferable coating amount of the heat-sensitive recording layer and the protective layer is 2 in the heat-sensitive recording layer.
10 to 10 g / m ² , more preferably 5 to 8 g / m ² . Similarly, the protective layer is suitably about ² to 10 g / m ² , more preferably 3 to 8 g / m ² .

The thermosensitive recording medium of the present invention may be provided with an underlayer between the support and the thermosensitive recording layer, if necessary, to improve the smoothness of the support surface and improve the sharpness of the image quality. Can be. Further, by providing a back layer on the surface of the support opposite to the surface on which the heat-sensitive recording layer is provided, it is possible to prevent various chemicals from penetrating from the back surface of the heat-sensitive recording medium, thereby making the heat-sensitive recording layer unnecessary. Coloring and decoloring of the recorded image can be prevented. The under layer and the back layer are mainly formed of various water-soluble or water-dispersible polymer compounds which are binders used in the heat-sensitive recording layer, and are formed by adding pigments and various additives as necessary. can do. The coating amounts of the under layer and the back layer are both 0.5 to 10 g / m ^2.
The degree is preferred. The surface smoothness can be further improved by performing a calendering process after the under layer is applied.

Further, the thermal recording medium of the present invention can provide excellent printing on water-based ink by providing a magnetic recording layer between the support and the thermal recording layer or on the surface of the support on which the thermal recording layer is not provided. As a suitable thermosensitive magnetic recording medium, it can be used for a wide range of uses, for example, as tickets such as a ticket, a pass, a parking ticket, and the like. The magnetic recording layer is made of, for example, γ-Fe ₂ O ₃ , Fe ₃ O ₄ , Co-γ-F
A magnetic substance such as e ₂ O ₃ or BaO · 6Fe ₂ O ₃ is prepared by kneading and dispersing with a suitable binder resin, for example, a polymer compound such as a polyester resin or a polyurethane resin, and various additives and solvents. What is necessary is just to apply and dry the applied paint on the support and to install it. In this case, various coating methods can be applied as in the case of providing the heat-sensitive recording layer and the protective layer. Further, a magnetic recording layer having excellent wear resistance and heat resistance can be provided by using an ultraviolet curable binder or an electron beam curable binder for the magnetic recording layer. When a heat-sensitive recording layer is provided on the magnetic recording layer, it is preferable to provide a hiding layer for hiding coloring of the magnetic recording layer between the magnetic recording layer and the heat-sensitive recording layer.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments. In addition, the number of parts indicating the combination is all parts by weight. Example 1 The following composition [A] was prepared for producing a coating material for a heat-sensitive recording layer.
A dispersion liquid consisting of [B] and [C] was prepared. [A] liquid ・ 30 parts of 3-dibutylamino-6-methyl-7-anilinofluoran ・ 50 parts of an aqueous methylcellulose solution (solid content concentration: 5%) ・ 20 parts of water [B] liquid ・ 4-isopropoxy-4 ′ -Hydroxydiphenyl sulfone 30 parts ・ Polyvinyl alcohol aqueous solution (solid content concentration 5%) 50 parts ・ Water 20 parts [C] solution ・ Kaolin 40 parts ・ Polyvinyl alcohol aqueous solution (solid content concentration 5%) 40 parts ・ Water 20 parts

[A] to [C] obtained as described above.
Of the following composition was prepared using the above dispersion liquid, and a dry weight of 7 g / m ^{2 was applied to} a high-quality paper having a basis weight of 60 g / m ^2.
And a heat-sensitive recording layer was provided.・ [A] solution 30 parts ・ [B] solution 90 parts ・ [C] solution 100 parts ・ Polyvinyl alcohol aqueous solution (solid content concentration 10%) 150 parts Next, a paint having the following composition was prepared as a protective layer.
Coating was performed on the heat-sensitive recording layer at a dry coating amount of 4 g / m ² to prepare a heat-sensitive recording medium of the present invention.・ 100 parts of carboxyl-modified polyvinyl alcohol aqueous solution (trade name “Gohsenol T330”, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., solid content concentration: 10%) ・ 12 parts of polyamide epoxy resin (trade name “Sparamine A301”, manufactured by Toho Chemical Company, solid content 84 parts of swellable mica aqueous dispersion (trade name "ME-100", manufactured by Corp Chemical Co., Ltd., solid content concentration 5%) 10 parts of [C] liquid 10 parts aqueous dispersion of zinc stearate (solid 5%

Example 2 Except that the following composition was used as the coating for the protective layer,
A thermosensitive recording medium of the present invention was produced in exactly the same manner as in Example 1.・ 100 parts of carboxyl-modified polyvinyl alcohol aqueous solution (trade name “Gohsenol T330”) ・ 12 parts of polyamide epoxy resin (trade name “Sparamine A301”) ・ 126 parts of swellable mica aqueous dispersion (trade name “ME-100”) 126 parts C] Liquid 5 parts-Aqueous dispersion of zinc stearate (solid content concentration 10%) 5 parts Example 3 Except for using the following composition as a protective layer paint,
A thermosensitive recording medium of the present invention was produced in exactly the same manner as in Example 1.・ Carboxy-modified polyvinyl alcohol aqueous solution 100 parts (trade name “Gohsenol T330”) ・ Polyamide epoxy resin (trade name “Sparamine A301”) 12 parts ・ Swellable aqueous mica dispersion (trade name “ME-100”) 168 parts ・ Stearin Aqueous dispersion of zinc acid (solid content 10%) 5 parts

Example 4 A coating composition for the protective layer having the following composition was used.
A thermosensitive recording medium of the present invention was produced in exactly the same manner as in Example 1.・ 80 parts of carboxyl-modified polyvinyl alcohol aqueous solution (trade name “Gohsenol T330”) ・ 10 parts of polyamide epoxy resin (trade name “Sparamine A301”) ・ 168 parts of swellable mica aqueous dispersion (trade name “ME-100”) 168 parts ・ Stearin Aqueous dispersion of zinc acid (solid content: 10%) 4 parts Example 5 Except that the following composition was used as the coating for the protective layer,
A thermosensitive recording medium of the present invention was produced in exactly the same manner as in Example 1.・ 100 parts of aqueous solution of polyvinyl alcohol (solid content 10%) ・ 4.5 parts of melamine resin waterproofing agent (trade name “SUMIREZ SR613”, manufactured by Sumitomo Chemical Co., Ltd., solid content 80%) ・ Swellable mica water dispersion 80 parts of liquid (trade name “ME-100”) 10 parts of [C] liquid 5 parts of aqueous dispersion of zinc stearate (solid content 10%)

Example 6 The procedure was the same as in Example 1 except that an aqueous dispersion of smectite (trade name “SWN”, manufactured by Corp Chemical Co., 5% solid content) was used as the swellable mica in the coating material for the protective layer. Thus, a thermosensitive recording medium of the present invention was produced. Example 7 The present invention was carried out in exactly the same manner as in Example 2, except that an aqueous dispersion of smectite (trade name “SWF”, manufactured by Corp Chemical Co., having a solid content of 5%) was used as the swellable mica in the coating material for the protective layer. Was prepared.

Example 8 A heat-sensitive recording medium of the present invention was produced in exactly the same manner as in Example 3, except that an aqueous dispersion of smectite (trade name “SWN”) was used as the swellable mica in the coating material for the protective layer. Example 9 A heat-sensitive recording medium of the present invention was produced in exactly the same manner as in Example 4, except that an aqueous dispersion of smectite (trade name “SWN”) was used as the swellable mica in the coating material for the protective layer.

Example 10 A high-quality paper of 137 g / m ² was used as a support, and a magnetic recording layer having a thickness of 13 μm was previously coated on the surface opposite to the surface on which the heat-sensitive recording layer was provided using a coating material for a magnetic recording layer having the following composition. Except that a recording layer was provided, a thermosensitive recording medium of the present invention having a magnetic recording layer was manufactured in exactly the same manner as in Example 1. 100 parts of barium ferrite (coercivity 3000 Oersted, average particle diameter 0.6 μm) 40 parts of polyester resin (Byron 200, manufactured by Toyobo Co., Ltd.) 5 parts of carbon black (Mitsubishi Carbon # 40, manufactured by Mitsubishi Kasei Co., Ltd.) Lecithin 2 parts ・ Methyl ethyl ketone 150 parts ・ Toluene 180 parts

Example 11 A heat-sensitive recording medium of the present invention having a magnetic recording layer was produced in exactly the same manner as in Example 10, except that the same coating material as in Example 3 was used as the coating material for the protective layer. Example 12 A thermosensitive recording medium of the present invention having a magnetic recording layer was produced in exactly the same manner as in Example 10, except that the same coating material as in Example 6 was used as the coating material for the protective layer. Example 13 A thermosensitive recording medium of the present invention having a magnetic recording layer was produced in exactly the same manner as in Example 10, except that the same coating material as in Example 8 was used as the coating material for the protective layer.

Comparative Example 1 Except for using the following composition as the coating for the protective layer,
A comparative thermosensitive recording medium was produced in exactly the same manner as in Example 1. -100 parts of a carboxyl-modified polyvinyl alcohol aqueous solution (trade name "Gohsenol T330")-20 parts of [C] liquid-5 parts of aqueous dispersion of zinc stearate (solid content: 10%) Comparative Example 2 The following composition as a coating for a protective layer Except that I used
A comparative thermosensitive recording medium was produced in exactly the same manner as in Example 1.・ Polyvinylpyrrolidone K-90 aqueous solution (solid content concentration 10%) 100 parts ・ [C] solution 20 parts ・ Zinc stearate aqueous dispersion (solid content concentration 10%) 5 parts

Comparative Example 3 Except that the following composition was used as the coating for the protective layer,
A comparative thermosensitive recording medium was produced in exactly the same manner as in Example 1.・ Carboxy-modified polyvinyl alcohol aqueous solution 100 parts (trade name “Gohsenol T330”) ・ Polyamide epoxy resin (trade name “Sparamine A301”) 12 parts ・ Seica (trade name “Microclean”, Dowa Mining Co., Ltd.) 4.2 parts -[C] solution 10 parts-Aqueous dispersion of zinc stearate (solid content concentration 10%) 5 parts Comparative Example 4 The same procedure as in Example 1 was carried out except that the coating material for the protective layer had the following composition. Thus, a heat-sensitive recording medium for comparison was prepared.・ Carboxy-modified polyvinyl alcohol aqueous solution 100 parts (trade name “Gohsenol T330”) ・ Polyamide epoxy resin (trade name “Sparamine A301”) 1.7 parts ・ Calcium carbonate 4.2 parts ・ [C] liquid 10 parts ・ Zinc stearate Aqueous dispersion (solids concentration 10%) 5 parts

With respect to the heat-sensitive recording media obtained in Examples 1 to 13 and Comparative Examples 1 to 4, each item was evaluated by the following methods, and the results are shown in Table 1. <Recording characteristics> Applied power 0.5 W / dot, pulse width 1.0 msec with a thermal printing device manufactured by Matsushita Electronic Components Co., Ltd.
And the density of the solid black portion is measured using a Macbeth reflection densitometer RD-
At 914, the recording density was evaluated. <Printability> Using a stamp using water-based ink,
Ten seconds after stamp printing on the protective layer, the printed portion was rubbed with a fingertip to evaluate dryness and fixability.も の: Printing was hardly obtained due to friction, か な り: Printing was considerable, ×: Printing was hardly obtained and was not practical.
And

<Blocking Resistance> In an environment of 30 ° C. and 80% RH, a stack of 20 thermosensitive recording media and a load of 60
The coating was left standing for 24 hours under the condition of kg / m ² , and a test for blocking of the coated surface was performed. A sample having almost no blocking and having no practical problem at all was rated as ○, and a sample having blocking occurred was rated as ×. <Barrier Property of Protective Layer> Methyl alcohol was applied to the surface of the protective layer, and a chemical barrier test of the protective layer was performed. In the case of poor barrier properties, methyl alcohol penetrates and reaches the heat-sensitive recording layer to form color. Therefore, the barrier properties of the protective layer were visually evaluated.も の indicates no color development, and x indicates color development.

[0032]

[Table 1] As is clear from Table 1, the heat-sensitive recording medium of the present invention is an excellent heat-sensitive recording medium having good printability for water-based inks without impairing properties such as recording properties, blocking properties, and barrier properties. It was confirmed that there was. Also,
The thermosensitive magnetic recording media obtained in Examples 10 to 13 were further applied to a ticket vending machine having a thermosensitive recording mechanism, in which predetermined magnetic information was written, read, and the balance indicated was applied to the thermosensitive recording surface. It was confirmed that there was no problem in practical use.

[0033]

The heat-sensitive recording medium of the present invention has an excellent effect that the printability to water-based ink is good without impairing the necessary properties such as recording properties, chemical resistance, water resistance and blocking resistance. Things. Further, by providing a magnetic recording layer on the heat-sensitive recording medium of the present invention, it can be widely used as a heat-sensitive magnetic recording medium having excellent printability for water-based ink, for example, as a ticket such as a ticket, a pass, a parking ticket, and the like. It can be used for.

Claims (4)

(57) [Claims] 1. A thermosensitive recording medium comprising a thermosensitive recording layer and a protective layer sequentially laminated on at least one surface of a support,
A thermosensitive recording medium, wherein the protective layer contains a water-soluble or water-dispersible polymer compound and at least one mica selected from the compounds represented by the following general formula (1). _{(Na, Li) m Mg n} Li 6-2n-m Si 4 O 10 (F, OH) 2 (1) [ The number in the range of wherein, m is 1/3 to 1, n is 2-8 / 3 Represents] 2. The thermosensitive recording medium according to claim 1, wherein the mixing ratio of the mica is 5 to 60% by weight based on the total solid content of the protective layer. 3. The heat-sensitive material according to claim 1, wherein the water-soluble or water-dispersible polymer compound is a carboxyl-modified polyvinyl alcohol, and a polyamide epoxy resin is used in combination as a crosslinking agent. recoding media. 4. The thermosensitive recording medium according to claim 1, wherein a magnetic recording layer is provided between the support and the thermosensitive recording layer or on a surface of the support where the thermosensitive recording layer is not provided. recoding media.