JPH06210959A - Thermal recording medium - Google Patents

Abstract

(57) [Summary] [Object] The present invention provides a heat-sensitive recording medium having excellent printability for an aqueous ink without deteriorating necessary properties such as recording properties and storage stability. In a thermosensitive recording medium comprising a thermosensitive recording layer and a protective layer which are sequentially laminated on at least one side of a support, the protective layer is represented by a water-soluble or water-dispersible polymer compound and the following general formula (1). A thermal recording medium containing at least one mica selected from the compounds described below. (Na, Li) _m Mg _n Li _6-2n-m Si ₄ O ₁₀ (F, OH) ₂ (1) [wherein m is a number in the range of 1/3 to 1 and n is 2 to 8/3] [Effect] Since the thermal recording medium of the present invention has the effect of being excellent in printability for water-based ink,
In particular, ticket papers, pass tickets, prepaid cards, P
It can be applied to a wide range of applications such as OS labels.

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 on a water-based ink on its surface, and in particular, ticket papers such as tickets and pass tickets, cards such as prepaid cards, and POS (Point of Point). Sales) The present invention relates to a thermal recording medium that can be applied to labels such as labels.

[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 developer which reacts with the leuco dye to develop a color is disclosed in JP-B-45-45.
Published in No. 14035, etc., it has been widely put into practical use. To perform recording on this heat-sensitive recording medium, a thermal printer or the like having a built-in thermal head is used. Compared to other conventional recording methods, such a thermal recording method has less noise during recording, does not require development and fixing, is maintenance-free, is relatively inexpensive and compact in equipment, and produces colors It is widely used as computer output, facsimile, recorder paper for calculators and various measuring machines, and ticket paper for automatic ticket vending machines because it has a very clear image.

As described above, conventional thermal recording media used for various purposes are required to have not only recording characteristics but also image storage stability such as chemical resistance and water resistance. As proposed in Japanese Patent Laid-Open No. 188392 and others, it has a structure in which a protective layer is provided on the heat-sensitive recording layer. The composition of such a protective layer is generally a water-soluble or water-dispersible polymer compound to which various additives such as pigments are added. 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 field of labels such as POS labels and ticket paper such as tickets, and in particular, in tickets, stamps using water-based ink are used instead of conventional scissors. The ticket inspection method is adopted.

However, although the conventional thermosensitive recording media have been fully examined for their recording characteristics, chemical resistance, water resistance and the like as described above, they are not suitable for printing such as ink absorption, drying and fixing properties for water-based ink. Printability was poor as little consideration was given. That is, a water-soluble resin such as polyvinyl alcohol that has been conventionally used as a protective layer does not provide sufficient printability for water-based inks, and further, in order to improve blocking resistance under high humidity conditions, an emulsion type Since water absorption is suppressed by using a resin or a water-proofing agent to suppress water absorption, it has an adverse effect on printability with respect to water-based ink, which has an adverse effect. In addition, it is possible to improve the absorbability of the water-based ink by increasing the addition amount of the pigment, but the transparency of the protective layer is lowered and the sharpness of the image of the thermosensitive recording layer is lowered. Will end up. in this way,
In the conventional thermal recording medium, the printability of the water-based ink cannot be satisfied, and a heat-sensitive recording medium having excellent printability of the water-based ink at the same time as good recording characteristics and image storability is desired. is there.

[0005]

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

[0006]

The present invention provides a thermosensitive recording medium in which a thermosensitive recording layer and a protective layer are sequentially laminated on at least one surface of a support, and the protective layer is a water-soluble or water-dispersible polymer. A thermal 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) [wherein m is a number in the range of 1/3 to 1 and n is 2 to 8/3] Represents]

The following compounds can be exemplified as the mica represented by the above general formula (1) used in the protective layer in the present invention. 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 (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 ion of naturally occurring mica is replaced with sodium ion or lithium ion, and has a swelling property in water. In the present invention, the term mica is used to include vermiculite and montmorillonite. Mica used in the present invention is, for example, “M
E-100 "(made by Corp Chemical)," Smectite SWF "(made by Corp Chemical)," Smectite SW "
It is marketed under the trade name of N "(made 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 is composed of at least the mica represented by the above general formula (1) and a water-soluble or water-dispersible polymer compound. Examples of such polymer compounds include 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, and the like, which may be used alone or Used as a mixture. Among these, preferable polymer compounds include blending properties with mica, printability for aqueous ink, and the like, carboxyl-modified polyvinyl alcohol, polyvinyl alcohol-based resins such as polyvinyl alcohol, water-soluble polyvinyl acetal resin, polyvinylpyrrolidone, and the like. Is exemplified. In addition, in the present invention, in order to obtain excellent water resistance, it is preferable to use a water resistant agent such as polyamide epoxy resin, melamine resin, melamine formaldehyde resin, polyamide resin, glyoxal, and chrome alum.

In the present invention, in order to obtain more excellent coatability (barrier property), chemical resistance, water resistance and the like, among the above-mentioned polymer compounds and water-proofing agents, carboxyl-modified polyvinyl alcohol and polyamide epoxy resin are combined. It is particularly preferable to use. Here, the carboxyl-modified polyvinyl alcohol is a polyvinyl alcohol having one free acid type carboxyl group or a carboxyl group having a metal salt form in the molecule. These carboxyl-modified polyvinyl alcohols can be obtained, for example, by saponifying a copolymer of vinyl acetate and (meth) acrylic acid, fumaric acid, maleic acid, itaconic acid or the like. The polyamide-epoxy resin is a compound having a glycidyl group in the molecule obtained by reacting a polyamide resin obtained by condensation of an alkylpolyamine compound and an alkyldicarboxylic acid with epichlorohydrin, and is, for example, SPARAMINE A3 manufactured by Toho Chemical Industry.
01 (trade 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 a cross-linking agent, the reaction proceeds even at room temperature, where it is difficult to cross-link with a general cross-linking agent, and good water resistance and coating property can be given to the protective layer. In the case of a heat-sensitive recording material such as the present invention, a high temperature cannot be applied to cure the cross-linking agent, and therefore 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 a good room temperature crosslinking property. The amount of polyamide epoxy resin added to the protective layer is 5 to 10 relative to 100 parts by weight of the carboxyl-modified polyvinyl alcohol in terms of solid content in the protective layer.
0 parts by weight is preferable, and 30 to 80 parts by weight is particularly preferable. If the amount of the polyamide epoxy resin added is 5 parts by weight or less, not only the crosslinking reaction time will be required, but also the coating properties may be insufficient, and more excellent barrier properties, chemical resistance and water resistance may not be obtained. On the other hand, if the blending ratio exceeds 100 parts by weight, the epoxy group in the polyamide epoxy resin may react with the leuco dye and the thermosensitive layer may be colored, which is not preferable.

Further, in the protective layer of the heat-sensitive recording medium of the present invention, various pigments such as clay, talc, diatomaceous earth, alumina, calcium carbonate, and the like may be added in order to obtain matching property with the heat-sensitive head. Calcium sulfate, zeolite, cellulose fine powder, polyethylene fine powder, silicone resin fine powder, phenol resin fine powder, benzoguanamine resin fine powder, etc. can be used, and lubricants such as zinc stearate and calcium stearate, fluororesin, and silicone grease. A release agent such as the above can be used.

In the protective layer having the above composition,
The content of mica is 5 to 60% by weight based on the total solid content in the layer.
Is preferable, and 20 to 50% by weight is particularly preferable. If the content of mica is less than 5% by weight, sufficient printability for water-based ink cannot be obtained.
If it exceeds 5% by weight, the barrier property of the protective layer may be deteriorated and chemical resistance and water resistance may not be sufficiently obtained. In the present invention, by forming the protective layer as described above,
It is possible to obtain good printability for water-based ink without impairing the properties such as coating property, chemical resistance, and water resistance required for the protective layer.

Next, the heat-sensitive recording layer in the present invention will be described. The heat-sensitive recording layer contains a colorless or light-colored leuco dye and a color developer that develops the color of 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-dibenzylaminofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 3-piperidino-6-methyl-7-anilinofluorane, 3-cyclohexylmethylamino-6- Methyl-7-anilinofluorane, 3-ethylisoamylamino-6-methyl-7
-Anilinofluorane, 3-diethylamino-7- (о
-Chloroanilino) fluorane, 3-dibutylamino-
7- (o-chloroanilino) fluorane and the like, but not limited thereto. Further, as the color developer which reacts with the leuco dye to develop 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′-cyclohexylidene diphenol, 2,2-bis (2,5-)
Dibromo-4-hydroxyphenyl) propane, 4,
4'-isopropylidene bis (2-t-butylphenol), 2,2'-methylenebis (4-chlorophenol), 4,4'-thiodiphenol, 4,4'-sulfonyldiphenol, benzoic acid, salicylic acid, There are derivatives such as gallic acid, but not limited to these.

As the binder used in the heat-sensitive recording layer, various water-soluble or water-dispersible polymer compounds are used, and polymer compounds that can be used in the protective layer can be appropriately used. . Furthermore, in the thermosensitive recording layer,
Various heat-fusible substances can be added as necessary 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 stearic acid amide, animal waxes such as beeswax and shellac wax,
Vegetable wax such as carnauba wax, mineral wax such as montan wax, paraffin wax, microcrystalline wax, higher fatty acid, ester of higher fatty acid, aromatic carboxylic acid ester such as dimethyl terephthalate, diphenyl phthalate, alkylnaphthalene derivative, alkyldiphenyl Derivatives, alkyl terphenyl derivatives and the like are used. Furthermore, in the heat-sensitive recording layer, inorganic and organic pigments as a filler, such as clay, talc, diatomaceous earth, alumina, calcium carbonate,
Calcium sulfate, zeolite, cellulose fine powder, polyethylene fine powder, silicone resin fine powder, phenol resin fine powder, benzoguanamine resin fine powder and the like can be added to improve the sharpness of the color image. In addition, various surfactants, antifoaming agents, antioxidants, and ultraviolet absorbers can be added as required.

The heat-sensitive recording layer in the present invention has the composition as described above, and a coating material comprising the above-mentioned leuco dye, a color developer and a binder, and other compounds added as necessary is provided on a support. Although it is provided by coating and drying, such a paint is a dispersion liquid pulverized by a disperser such as a media type wet disperser, and the particle size of the leuco dye, the color developer or the like to be dispersed. Is 5 μm or less, particularly preferably 3
It is desirable that the thickness be less than or equal to μm in terms of recording characteristics.

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,
Woven fabrics, non-woven fabrics, and composites of these 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 prepared by dispersing or dissolving the materials for forming each layer described above is used for roll coating method, blade coating method, spray coating method. , Air knife coating method, rod bar coating method and the like. The preferable coating amount of the heat-sensitive recording layer and the protective layer is 2 in the heat-sensitive recording layer.
It is 10 to 10 g / m ² , and more preferably 5 to 8 g / m ² . Similarly, the protective layer is also preferably about ² to 10 g / m ² , but more preferably 3 to 8 g / m ² .

The thermal recording medium of the present invention may further comprise an under layer between the support and the thermal recording layer to enhance the smoothness of the surface of the support and improve the sharpness of image quality. You can Further, by providing a back layer on the surface of the support opposite to the surface on which the thermosensitive recording layer is provided, it is possible to prevent the penetration of various chemicals from the back surface of the thermosensitive recording medium and eliminate the need for the thermosensitive recording layer. It is possible to prevent coloring and erasing of recorded images. The under layer and the back layer are formed by mainly using various water-soluble or water-dispersible polymer compounds that are binders used in the thermosensitive recording layer, and by adding pigments and various additives as necessary. can do. The coating amount of both the under layer and the back layer is 0.5 to 10 g / m ²
A degree is preferable. It is also possible to further improve the surface smoothness by applying a calendar treatment after coating the under layer.

Further, in the heat-sensitive recording medium of the present invention, by providing the magnetic recording layer between the support and the heat-sensitive recording layer or on the surface of the support on which the heat-sensitive recording layer is not provided, excellent printing with water-based ink is possible. The heat-sensitive magnetic recording medium having suitability can be used in a wide range of applications as ticket papers such as boarding tickets, pass tickets, and parking tickets. The magnetic recording layer is formed of, for example, γ-Fe ₂ O ₃ , Fe ₃ O ₄ , Co-γ-F.
Preparation of magnetic materials such as e ₂ O ₃ and BaO.6Fe ₂ O ₃ by kneading / dispersing a suitable binder resin, for example, a polymer compound such as polyester resin or polyurethane resin, various additives, solvents, etc. The coating composition may be applied on a support, dried, and set. As a method at this time, 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 abrasion resistance and heat resistance can be provided by using an ultraviolet curable binder or an electron beam curable binder in the magnetic recording layer. When the heat-sensitive recording layer is provided on the magnetic recording layer, it is preferable to provide a hiding layer for hiding the coloring of the magnetic recording layer between the magnetic recording layer and the heat-sensitive recording layer.

[0020]

EXAMPLES The present invention will be described in detail below with reference to examples. In addition, all the numbers showing the composition represent parts by weight. Example 1 In order to produce a coating material for a heat-sensitive recording layer, the following composition [A] was used.
A dispersion liquid including [B] and [C] was prepared. [A] liquid-3-dibutylamino-6-methyl-7-anilinofluorane 30 parts-Methylcellulose aqueous solution (solid content concentration 5%) 50 parts-Water 20 parts [B] liquid-4-isopropoxy-4 ' -Hydroxydiphenyl sulfone 30 parts-Polyvinyl alcohol aqueous solution (solid content concentration 5%) 50 parts-Water 20 parts [C] liquid-Kaolin 40 parts-Polyvinyl alcohol aqueous solution (solid content concentration 5%) 40 parts-Water 20 parts

[A] to [C] obtained as described above
A coating material for the heat-sensitive recording layer having the following composition was prepared by using the dispersion liquid of No. 1, and a dry weight of 7 g / m ^{2 was applied to} a wood free paper having a basis weight of 60 g / m ^2.
And a thermal recording layer was provided. -[A] liquid 30 parts- [B] liquid 90 parts- [C] liquid 100 parts-Polyvinyl alcohol aqueous solution (solid content concentration 10%) 150 parts Next, a coating material having the following composition was prepared as a protective layer,
The above thermal recording layer was coated so as to have a dry coating amount of 4 g / m ² , to prepare a thermal recording medium of the present invention. -Carboxyl-modified polyvinyl alcohol aqueous solution 100 parts (trade name "Gothenol T330", manufactured by Nippon Synthetic Chemical Industry Co., Ltd., solid content concentration 10%)-Polyamide epoxy resin 12 parts (trade name "Sparamine A301", manufactured by Toho Chemical Co., solid content Concentration 30%)-Swelling mica water dispersion 84 parts (trade name "ME-100", manufactured by Corp Chemical Co., solid content concentration 5%)-[C] liquid 10 parts-Zinc stearate water dispersion (solid) Minute concentration 10%) 5 parts

Example 2 A protective layer coating material having the following composition was used, except that
A thermal recording medium of the present invention was produced in exactly the same manner as in Example 1. -Carboxyl-modified polyvinyl alcohol aqueous solution 100 parts (trade name "Gothenol T330")-Polyamide epoxy resin (trade name "Sparamine A301") 12 parts-Swellable mica water 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 that the following composition was used as the protective layer coating material.
A thermal recording medium of the present invention was produced in exactly the same manner as in Example 1. -Carboxyl-modified polyvinyl alcohol aqueous solution 100 parts (trade name "Gothenol T330")-Polyamide epoxy resin (trade name "Sparamine A301") 12 parts-Swellable mica water dispersion (trade name "ME-100") 168 parts-Stearin Aqueous dispersion of zincate (solid content 10%) 5 parts

Example 4 Except that the coating composition for the protective layer having the following composition was used,
A thermal recording medium of the present invention was produced in exactly the same manner as in Example 1. -Carboxyl-modified polyvinyl alcohol aqueous solution 80 parts (Product name "Gothenol T330")-Polyamide epoxy resin (Product name "Sparamine A301") 10 parts-Swellable mica water dispersion (Product name "ME-100") 168 parts-Stearin Aqueous dispersion of zinc oxide (solid content concentration 10%) 4 parts Example 5 A coating composition for the protective layer having the following composition was used, except that
A thermal recording medium of the present invention was produced in exactly the same manner as in Example 1. -Polyvinyl alcohol aqueous solution (solid content concentration 10%) 100 parts-Melamine-based resin water-proofing agent 4.5 parts (trade name "SUMIREZ SR613", Sumitomo Chemical Co., Ltd., solid content concentration 80%)-Swelling mica water dispersion Liquid (trade name "ME-100") 80 parts- [C] liquid 10 parts-Aqueous dispersion of zinc stearate (solid content 10%) 5 parts

Example 6 Exactly the same as in Example 1 except that a smectite aqueous dispersion (trade name "SWN", manufactured by Cope Chemical Co., solid concentration 5%) was used as the swelling mica in the coating material for the protective layer. To produce the thermal recording medium of the present invention. Example 7 The present invention was carried out in the same manner as in Example 2 except that a smectite aqueous dispersion (trade name "SWF", manufactured by Corp Corp., solid content concentration 5%) was used as the swellable mica in the coating material for protective layer. A heat-sensitive recording medium of was prepared.

Example 8 A thermosensitive recording medium of the present invention was prepared in exactly the same manner as in Example 3 except that a smectite aqueous dispersion (trade name "SWN") was used as the swelling mica in the protective layer coating material. Example 9 A thermosensitive recording medium of the present invention was produced in exactly the same manner as in Example 4 except that a smectite aqueous dispersion (trade name "SWN") was used as the swelling mica in the protective layer coating material.

Example 10 A high-quality paper of 137 g / m ² was used as a support, and a magnetic recording layer coating composition having the following composition was previously used on the surface opposite to the surface on which the heat-sensitive recording layer was provided. A thermosensitive recording medium of the present invention having a magnetic recording layer was produced in exactly the same manner as in Example 1 except that the recording layer was provided.・ Barium ferrite (coercive force 3000 oersted, average particle size 0.6 μm) 100 parts ・ Polyester resin (Byron 200, manufactured by Toyobo Co., Ltd.) 40 parts ・ Carbon black (Mitsubishi Carbon # 40, manufactured by Mitsubishi Kasei) 5 parts ・Lecithin 2 parts-Methyl ethyl ketone 150 parts-Toluene 180 parts

Example 11 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 3 was used as the protective layer coating material. 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 protective layer coating material. 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 protective layer coating material.

Comparative Example 1 A protective layer coating material having the following composition was used, except that
A thermal recording medium for comparison was prepared in exactly the same manner as in Example 1. -Carboxyl-modified polyvinyl alcohol aqueous solution 100 parts (trade name "Gothenol T330")-[C] liquid 20 parts-Aqueous dispersion of zinc stearate (solid content concentration 10%) 5 parts Comparative Example 2 The following composition for a protective layer paint Except that I used
A thermal recording medium for comparison was prepared 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 A protective layer coating material having the following composition was used, except that
A thermal recording medium for comparison was prepared in exactly the same manner as in Example 1. -Carboxyl-modified polyvinyl alcohol aqueous solution 100 parts (trade name "Gothenol T330")-Polyamide epoxy resin (trade name "Sparamine A301") 12 parts-Serum (trade name "Microclean", Dowa Mining Co., Ltd.) 4.2 parts -[C] liquid 10 parts-Aqueous dispersion of zinc stearate (solid content 10%) 5 parts Comparative Example 4 The same as Example 1 except that the protective layer coating material having the following composition was used. To prepare a thermal recording medium for comparison. -Carboxyl-modified polyvinyl alcohol aqueous solution 100 parts (trade name "Gothenol T330")-Polyamide epoxy resin (trade name "Sparamine A301") 1.7 parts-Calcium carbonate 4.2 parts- [C] liquid 10 parts-Zinc stearate 5 parts of aqueous dispersion (solid concentration 10%)

The thermal recording media obtained in Examples 1 to 13 and Comparative Examples 1 to 4 were evaluated for each item 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 printer manufactured by Matsushita Electronic Components Co., Ltd.
Recorded with, and the density of the black solid part is Macbeth reflection densitometer RD-
The recording density was evaluated by measuring at 914. <Printability> Using a stamp with water-based ink,
Ten seconds after the stamp was printed on the protective layer, the printed part was rubbed with a fingertip to evaluate the drying property and the fixing property. ○: Prints that are hardly printed due to friction, △: Prints that are fairly printed, ×: Prints that are hardly printed and cannot be put to practical use
And

<Blocking resistance> Under the environment of 30 ° C. and 80% RH, 20 thermal recording media are stacked and a load of 60 is applied.
After standing for 24 hours under the condition of kg / m ² , a blocking test of the coated surface was conducted. When there was almost no blocking and there was no problem in practical use, it was marked with ◯, and when blocking occurred, it was marked with x. <Barrier Property of Protective Layer> Methyl alcohol was applied to the surface of the protective layer to test the chemical resistance of the protective layer. In the case of poor barrier property, methyl alcohol penetrates and reaches the heat-sensitive recording layer to generate color, so the barrier property of the protective layer was evaluated visually. The case where no color development was observed at all was evaluated as ◯, and the case where color development was observed was evaluated as x.

[0032]

[Table 1] As is clear from Table 1, the thermosensitive recording medium of the present invention is an excellent thermosensitive recording medium having good printability for water-based ink without deteriorating the characteristics such as recording characteristics, blocking property and barrier property. It was confirmed that there is. Also,
The thermosensitive magnetic recording media obtained in Examples 10 to 13 were applied to a vending machine for cash vouchers further having a thermosensitive recording mechanism, and predetermined magnetic information was written, read, and the balance display amount 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 it has good printability for water-based ink without deteriorating necessary characteristics such as recording characteristics, chemical resistance, water resistance and blocking resistance. It is a thing. Further, by providing a magnetic recording layer on the thermosensitive recording medium of the present invention, as a thermosensitive magnetic recording medium having excellent printability for water-based ink, for example, a wide range of applications such as ticket, pass ticket, parking ticket, etc. Can be used for.

Claims (4)

[Claims] 1. A thermosensitive recording medium comprising a thermosensitive recording layer and a protective layer which are sequentially laminated on at least one surface of a support,
A thermal 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) [wherein m is a number in the range of 1/3 to 1 and n is 2 to 8/3] Represents] 2. The thermosensitive recording medium according to claim 1, wherein the proportion of the mica compounded 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 carboxyl-modified polyvinyl alcohol, and a polyamide epoxy resin is also used as a crosslinking agent. recoding media. 4. The heat-sensitive material according to claim 1, wherein a magnetic recording layer is provided between the support and the heat-sensitive recording layer or on the surface of the support on which the heat-sensitive recording layer is not provided. recoding media.