Thermal recorder

Abstract

The present invention aims to provide a thermal recorder with excellent transparency. The thermal recorder of the present invention is characterized by having a thermal layer containing a fatty acid-based wax. The fatty acid-based wax is preferably a solubilized fatty acid-based wax and / or an emulsion-type fatty acid-based wax. Furthermore, the fatty acid-based wax is preferably a solubilized fatty acid-based wax. Additionally, the solubilized fatty acid-based wax is preferably a solubilizing agent.

Description

Technology Field

[0001] The present invention relates to a thermal recording body. Background Technology

[0002] Thermal recording materials produce a recorded image by generating color through a chemical reaction caused by heating, such as with a thermal head. They are used in a wide range of applications, including as recording media for fax machines, automatic ticket machines, and scientific instruments, as well as for thermal recording labels and receipt paper for POS systems in retail stores.

[0003] In particular, when using thermal recorders as labels for food containers such as lunch boxes or as food packaging films, there is a problem in that the contents cannot be seen if an opaque thermal recorder is used; therefore, a thermal recorder with excellent transparency is required to allow the contents to be clearly seen.

[0004] As a thermal recorder with excellent transparency, for example, a thermal recorder is proposed in which the thermal recorder layer comprises a dispersant having a carboxyl group and a crosslinking agent having an epichlorohydrin-modified polyamide polyamine resin or an organic compound containing an oxazoline group as a main component, and it is disclosed that transparency is further improved by using a material with a fine particle size (for example, see Patent Document 1). Prior art literature

[0005] International Publication No. 2021 / 106076 The problem to be solved

[0006] However, the review of thermal recorders with excellent transparency was not yet sufficient, leaving room for further examination.

[0007] Accordingly, the objective of the present invention is to provide a thermal recorder with excellent transparency. means of solving the problem

[0008] As a result of careful consideration to solve the above problem, the inventors discovered that by incorporating a fatty acid-based wax into the thermal layer, a thermal recording material with excellent transparency can be provided. The present invention was completed based on these findings.

[0009] That is, the present invention provides a thermal recorder having a thermal layer containing a fatty acid-based wax. The thermal recorder has excellent transparency because the thermal layer contains a fatty acid-based wax.

[0010] The above fatty acid-based wax is preferably a solubilized fatty acid-based wax and / or an emulsion-type fatty acid-based wax. By having such a composition, transparency can be further improved.

[0011] Preferably, the above fatty acid-based wax is a solubilized fatty acid-based wax. By having such a composition, transparency can be further improved.

[0012] It is preferable that the above-mentioned solubilized fatty acid-based wax contains a solubilizing agent. By having such a composition, transparency can be further improved.

[0013] The thermal layer preferably contains a surfactant and / or a solvent. By having such a composition, transparency can be further improved.

[0014] The above thermal layer preferably further contains a wax other than a fatty acid-based wax, and also contains a wax with an average particle size of 1 μm or less. By having such a composition, transparency can be further improved.

[0015] It is preferable that the content ratio of the fatty acid-based wax is 0.1 mass% or more and 5 mass% or less with respect to 100 mass% of the dry mass of the thermal layer. By having such a composition, transparency can be further improved.

[0016] In addition, the present invention comprises a process for preparing a paint for a thermal layer using a solubilized fatty acid-based wax and / or an emulsion-type fatty acid-based wax, and

[0017] The present invention provides a method for manufacturing a thermal recorder comprising a process of forming a thermal layer by applying and drying the above-described thermal layer paint. A thermal recorder manufactured by such a method has excellent transparency. Effects of the invention

[0018] According to the present invention, a thermal recording material with excellent transparency can be provided. Brief explanation of the drawing

[0019] FIG. 1 is a schematic cross-sectional view showing one embodiment of a thermal recording body of the present invention. Specific details for implementing the invention

[0020] [Thermal Recorder]

[0021] The thermal recorder of the present invention is a thermal recorder having a thermal layer containing fatty acid-based wax.

[0022] The thermal recorder of the present invention may have a substrate or an anchor layer. When the thermal recorder of the present invention has a substrate and an anchor layer, it is preferable that the thermal recorder of the present invention has the substrate, the anchor layer, and the thermal layer in that order. In addition, the thermal recorder of the present disclosure may have layers other than the above layers. Examples of layers other than the above layers include a back coat layer, an intermediate layer, a top coat layer, etc.

[0023] Hereinafter, an embodiment of the thermal recording body of the present invention will be described in detail based on the drawings, but the present invention is not limited to each of the following embodiments.

[0024] FIG. 1 is a schematic cross-sectional view showing one embodiment of a thermal recording body of the present invention.

[0025] The thermal recording body (1) of the present embodiment is provided with a substrate (2), an anchor layer (3), and a thermal layer (4) in this order, as shown in FIG. 1.

[0026] (write)

[0027] In this embodiment, the substrate (2) functions as a support for the thermal recording body (1). Additionally, for the substrate (2), for example, a transparent synthetic resin film can be used. Examples of the transparent synthetic resin film include a polypropylene film, a polyethylene terephthalate film, a polystyrene film, a polycarbonate film, etc. Additionally, the transparent synthetic resin film may be a biaxially stretched film or a film having heat sealing properties. Furthermore, the substrate (2) may be a single layer or a multilayer. The thickness of the substrate (2) is, for example, preferably 5 μm to 150 μm, and more preferably 10 μm to 100 μm. A thickness within the above range is desirable because it provides excellent coating properties and transparency. In addition, among the above-mentioned materials, biaxially oriented polypropylene (OPP) film and heat-sealing polyethylene terephthalate (HS-PET) film may be preferably used in terms of improving transparency or imparting functionality.

[0028] (Anchor layer)

[0029] In this embodiment, the anchor layer (3) functions as a layer that increases the adhesion between the substrate (2) and the thermal layer (4). The material forming the anchor layer (3) is not particularly limited, and only a binder may be used. In addition, the anchor layer (3) may contain other components, such as pigments, for example. Also, if the anchor layer is not required, it may not be formed.

[0030] The binder included in the anchor layer (3) above is not particularly limited and may include, for example, modified styrene-acrylic resin, acrylic emulsion, styrene-acrylic copolymer, modified styrene-butadiene latex, styrene-butadiene copolymer (SBR), acrylic-butadiene-styrene copolymer, vinyl acetate resin, vinyl acetate-acrylic acid copolymer, polyurethane resin, etc. Here, acrylic means acrylic acid (salt) and acrylic acid ester, and acrylic acid (salt) means acrylic acid and acrylate.

[0031] As the above-mentioned binder, it is preferable to use one or more selected from the group consisting of modified styrene-acrylic resin, acrylic emulsion, styrene-acrylic copolymer, acrylic-butadiene-styrene copolymer, and vinyl acetate-acrylic acid copolymer, and it is more preferable to use one or more selected from the group consisting of modified styrene-acrylic resin and acrylic emulsion. Among these, when using the above-mentioned modified styrene-acrylic resin, a modified styrene-acrylic acid (salt) resin is preferred. These binders may be used individually or in combination of two or more types.

[0032] The salts in the above acrylates are not particularly limited and, for example, may be ammonium salts such as ammonia; alkanolamine salts such as triethanolamine, diethanolamine, monoethanolamine; alkylamine salts such as methylamine, ethylamine, diethylamine, and triethylamine; polyamine salts such as diethyleneamine and diethylenetriamine; alkali metal salts such as lithium, sodium, and potassium; alkaline earth metal salts such as magnesium and calcium; and polyvalent metal salts such as zinc and iron. Among these, ammonium salts are particularly preferred. These salts may be used alone or in combination of two or more types.

[0033] In addition, as binders other than those mentioned above, water-soluble polymers such as polyvinyl alcohol, starch and its derivatives, cellulose derivatives such as methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, and ethylcellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylamide-acrylic acid ester copolymer, acrylamide-acrylic acid ester-methacrylic acid terpolymer, styrene-maleic anhydride copolymer alkali salt, isobutylene-maleic anhydride copolymer alkali salt, polyacrylamide, sodium alginate, gelatin, and casein may be used. In addition, these binders may be used alone or in combination of two or more types.

[0034] The content ratio of the above binder is preferably 10 mass% or more, more preferably 20 mass% or more, even more preferably 50 mass% or more, even more preferably 70 mass% or more, even more preferably 80 mass% or more, and particularly preferably 90 mass% or more, with respect to 100 mass% of the dry mass of the above anchor layer (3). In addition, the content ratio of the above binder may substantially be 100 mass% with respect to 100 mass% of the dry mass of the above anchor layer (3). When the content ratio of the above binder is within the above range, it is desirable from the view that the adhesion between the substrate (2) and the thermal layer (4) is higher.

[0035] In addition, in this specification, "dry mass" means the mass of non-volatile components (solids) from which solvents (volatile components), such as water, contained in the paint or its raw materials have been removed by drying.

[0036] The coating amount (dry mass) of the above anchor layer (3) is, for example, preferably 0.3 g / m² 2 ~ 5.0 g / m² 2 and, more preferably 0.5 g / m 2 ~ 2.0 g / m² 2 am.

[0037] The thickness of the anchor layer (3) is, for example, preferably 0.3 μm to 5.0 μm, and more preferably 0.5 μm to 2.0 μm.

[0038] In this embodiment, when the amount and thickness of the anchor layer (3) are within the above range, it is preferable because the adhesion between the substrate (2) and the thermal layer (4) tends to be improved.

[0039] In this embodiment, when forming the anchor layer (3), the material for forming the anchor layer (3) can be selected according to the type of the substrate (2). For example, when a polypropylene film is used as the substrate (2), the anchor layer (3) preferably includes a modified styrene-acrylic resin as a binder, more preferably includes a modified styrene-acrylic acid (salt) resin, and more preferably includes a modified styrene-acrylic acid (ammonium salt) resin. In addition, the polypropylene film is particularly preferably a biaxially stretched polypropylene (OPP) film from the perspective of improving transparency or imparting functionality.

[0040] In addition, when a polyethylene terephthalate film is used as the above substrate (2), it is preferable that the anchor layer (3) includes an acrylic emulsion as a binder. As the acrylic emulsion, for example, a material commercially available under the name "AQUENCE EPIX BC AD81B" (manufactured by Henkel Japan Co., Ltd.) can be used. Furthermore, regarding the improvement of transparency and the imparting of functionality, a polyethylene terephthalate (HS-PET) film having heat sealing properties is particularly preferred for the above polyethylene terephthalate film. The combination of the above substrate (2) and the anchor layer (3) is preferred because the adhesion between the substrate (2) and the thermal layer (4) is further improved, and the transparency of the thermal recorder (1) tends to be further improved.

[0041] (Thermal layer)

[0042] In this embodiment, the thermal layer (4) functions as a layer that develops color upon heating. The thermal layer (4) contains at least a fatty acid-based wax.

[0043] In order to improve the transparency of the thermal recorder (1), it is desirable to use materials with a fine average particle size. By using materials with a fine average particle size, diffuse reflection of light by particles is suppressed, so the transparency of the thermal recorder (1) tends to improve.

[0044] In addition, in this specification, "average particle size" refers to the particle size (D50, median diameter) at 50% of the cumulative value in the particle size distribution measured by the laser diffraction and scattering method. The measurement of the average particle size by the laser diffraction and scattering method can be performed, for example, using the "MT3300EX-II" manufactured by Microtrack Bell. Hereinafter, "average particle size" refers to the median diameter measured by the above method.

[0045] The above fatty acid-based wax has the function of improving the transparency of the thermal recorder. Specifically, when forming the thermal layer (4), the fatty acid-based wax penetrates into the voids between particles of other components and seals the voids, thereby suppressing diffuse reflection of light in the voids, and as a result, it is presumed that the transparency of the thermal recorder is further improved. Examples of the above fatty acid-based waxes include fatty acids, fatty acid salts, fatty acid amides, fatty acid esters, etc. These fatty acid-based waxes can be used alone or in combination of two or more types.

[0046] Examples of the above fatty acids include, for instance, higher fatty acids having 10 to 22 carbon atoms. Examples of the above higher fatty acids include, for instance, higher saturated fatty acids having 10 to 22 carbon atoms such as capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, and behenic acid; and higher unsaturated fatty acids having 10 to 22 carbon atoms such as palmitoleic acid, oleic acid, elaidic acid, linoleic acid, and linolenic acid. These fatty acids may have substituents. Examples of the above substituents include hydroxyl groups.

[0047] Examples of the above fatty acid salts include, for instance, a salt obtained by neutralizing the above fatty acid. Examples of the above salts include, for instance, alkali metal salts such as lithium, sodium, and potassium; alkaline earth metal salts such as magnesium and calcium; and polyvalent metal salts such as zinc and iron. Specifically, examples of the above fatty acid salts include sodium stearate, potassium stearate, magnesium stearate, calcium stearate, zinc stearate, iron stearate, sodium oleate, potassium oleate, magnesium oleate, calcium oleate, zinc oleate, iron oleate, etc.

[0048] Examples of the above fatty acid amides include the amidation reaction product of the above fatty acid and ammonium or amine. Examples of the above amines include diamines such as ethylenediamine and hexamethylenediamine. Specifically, examples of the above fatty acid amides include capric acid amide, lauric acid amide, myristic acid amide, palmitic acid amide, stearic acid amide, arachidic acid amide, behenic acid amide, palmitoleic acid amide, oleic acid amide, elaidic acid amide, linoleic acid amide, linolenic acid amide, N,N'-ethylenebis(stearic acid amide), N,N'-hexamethylenebis(stearic acid amide), etc.

[0049] Examples of the above fatty acid esters include the esterification reaction product of the above fatty acid and a monohydric and / or polyhydric alcohol. Examples of the above monohydric alcohol and / or polyhydric alcohols include monohydric alcohols such as ethanol and propanol; polyhydric alcohols such as propylene glycol, glycerin, and sorbitol.

[0050] In the present embodiment, the fatty acid-based wax is preferably a solubilized fatty acid-based wax and / or an emulsion-type fatty acid-based wax, and more preferably a solubilized fatty acid-based wax. In this specification, a solubilized fatty acid-based wax means that it is soluble in a thermal layer or a paint for a thermal layer. By using the solubilized fatty acid-based wax and / or an emulsion-type fatty acid-based wax, the transparency of the thermal recorder tends to be improved. In particular, the solubilized fatty acid-based wax is soluble in a thermal layer or a paint for a thermal layer, and furthermore, the transparency of the thermal recorder tends to be improved.

[0051] The above-mentioned solubilized fatty acid-based wax may be soluble in the thermal layer or thermal layer paint as a fatty acid-based wax alone, or the fatty acid-based wax may be soluble in the thermal layer or thermal layer paint as a mixture thereof containing a solubilizing agent. Examples of the solubilizing agent include surfactants, solvents, and solvents used in thermal layer paints. Examples of the solvents in the thermal layer paint include organic solvents or water, and preferably water. Furthermore, if the above-mentioned solubilized fatty acid-based wax contains a solvent used in the thermal layer paint, it may contain a portion of the solvent or the entire amount of the solvent. From the perspective of ease of handling and solubilization, it is preferable that the above-mentioned solubilized fatty acid-based wax includes a fatty acid-based wax and a solubilizing agent. The above-mentioned solubilizing agent is preferably one or more selected from the group consisting of surfactants, solvents, and solvents used in thermal layer paints. In addition, as the above solubilizing agent, it is preferable to include a surfactant and / or a solvent and a part of the solvent of the paint for the thermal layer, and it is also preferable to include a surfactant and / or a solvent and not include the solvent of the paint for the thermal layer.

[0052] The fatty acid-based wax in the emulsion phase described above is a compound in which the fatty acid-based wax is self-emulsifying. It may be dispersed in the solvent of a thermal layer paint as a single component to form an emulsion phase, or it may be dispersed in the solvent of a thermal layer paint by means of a surfactant or the like to form an emulsion phase. Furthermore, in this specification, the fatty acid-based wax in the emulsion phase refers to a fatty acid-based wax that stably forms an emulsion. Furthermore, stably forming an emulsion means that, for example, when left standing for 24 hours at room temperature and atmospheric pressure, no change in state such as separation of components or precipitation is observed, and the emulsion state can be maintained.

[0053] In the present embodiment, the thermal layer (4) may contain other components other than the fatty acid-based wax, and may contain, for example, a dye, a developer, a filler, a binder, a dispersant, a crosslinking agent, a wax other than the fatty acid-based wax (other wax), a surfactant, a solvent, etc. Among these, it is preferable that the thermal layer (4) contains a surfactant and / or a solvent. The surfactant is not particularly limited and may be any component that has the function of improving the solubility of the fatty acid-based wax. Examples of the surfactant include anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, etc. These surfactants may be used alone or in combination of two or more types.

[0054] Examples of the above anionic surfactants include alkylbenzenesulfonic acid and / or its salt, alkylsulfonic acid and / or its salt, alkyl sulfate ester and / or its salt, alkyl ether sulfate ester and / or its salt, etc. Examples of the above anionic surfactant include an alkyl group having 10 to 22 carbon atoms. Examples of the above alkyl group include a saturated hydrocarbon group, an unsaturated hydrocarbon group, etc. The above alkyl group may have a substituent. Examples of the above substituent include a hydroxyl group, etc. Also, examples of the above salt include an ammonium salt such as ammonia; an alkanolamine salt such as triethanolamine; an alkali metal salt such as lithium, sodium, potassium, etc.; an alkaline earth metal salt such as magnesium, calcium, etc.; a polyvalent metal salt such as zinc, iron, etc.

[0055] Examples of the above nonionic surfactants include polyoxyethylene alkyl ether, polyoxypropylene alkyl ether, polyoxyalkylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene polyoxypropylene glycol, sorbitan alkyl ester, polyoxyethylene sorbitan alkyl ester, glycerin alkyl ester, polyoxyethylene glycerin alkyl ester, polyoxyethylene hardened castor oil, etc. The alkyl group having the above nonionic surfactant is not particularly limited and may include an alkyl group having 10 to 22 carbon atoms. Examples of the above alkyl group include a saturated hydrocarbon group, an unsaturated hydrocarbon group, etc. The above alkyl group may have a substituent. Examples of the above substituent include a hydroxyl group, etc.

[0056] The above solvent is not particularly limited and may be any component having the function of improving the solubility of the above fatty acid-based wax. Examples of the above solvents include glycol ethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether; glycols such as ethylene glycol, diethylene glycol, triethylene glycol, and propylene glycol; ethers such as diisopropyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, and 1,4-dioxane; alcohols such as methanol, ethanol, n-propanol, isopropanol, 2-ethylhexanol, and benzyl alcohol; and amines such as monoethanolamine, diethanolamine, and triethanolamine. Among these, from the perspective of handling and solubilizing fatty acid-based waxes, the solvent is preferably one or more selected from the group consisting of glycol ethers, glycols, ethers, and alcohols, more preferably one or more selected from the group consisting of glycol ethers and glycols, and even more preferably glycol ethers. When the solvent is a glycol ether, among them, diethylene glycol monobutyl ether is particularly preferred. These solvents may be used alone or in combination of two or more.

[0057] Furthermore, in this specification, compounds corresponding to fatty acid-based waxes and also corresponding to other components such as surfactants and solvents are classified only as fatty acid-based waxes and not as other components. Also, compounds that do not correspond to fatty acid-based waxes but may correspond to surfactants and solvents are classified only as surfactants and not as solvents.

[0058] The average particle size of the fatty acid-based wax is preferably 1.0 μm or less. It is preferable that the average particle size of the fatty acid-based wax be within the above range because the transparency of the thermal recorder (1) tends to be improved.

[0059] The content ratio of the fatty acid-based wax is preferably 0.1 mass% or more, more preferably 0.5 mass% or more, and even more preferably 1 mass% or more, with respect to 100 mass% of the dry mass of the thermal layer (4). In addition, the content ratio of the fatty acid-based wax is preferably 5 mass% or less, more preferably 4 mass% or less, and even more preferably 3 mass% or less, with respect to 100 mass% of the dry mass of the thermal layer (4). It is preferable that the content ratio of the fatty acid-based wax is within the above range because the transparency of the thermal recorder (1) tends to be further improved.

[0060] In addition, in this specification, "content ratio of fatty acid-based wax" means the content ratio of the total dry mass of the fatty acid-based wax and the dry mass of the solubilizer when the fatty acid-based wax contains a solubilizer. In addition, when the fatty acid-based wax is in the emulsion phase and contains a surfactant, it means the content ratio of the dry mass of the emulsion containing the surfactant.

[0061] In this embodiment, in order to further improve the long-term water resistance of the thermal recorder (1), it is preferable that the thermal layer (4) includes a wax other than the fatty acid-based wax (other wax). Examples of waxes other than the fatty acid-based wax may include polystyrene, polyethylene, paraffin, etc. Among these, in order to further improve the long-term water resistance and transparency of the thermal recorder (1), it is preferable that the wax other than the fatty acid-based wax be one or more selected from the group consisting of polystyrene and polyethylene, and polystyrene is more preferable. These waxes may be used alone or in combination of two or more types.

[0062] The average particle size of the wax other than the fatty acid-based wax is preferably 0.1 μm or more. In addition, the average particle size of the wax other than the fatty acid-based wax is preferably 1.0 μm or less, more preferably 0.6 μm or less, even more preferably 0.55 μm or less, even more preferably 0.4 μm or less, and particularly preferably 0.3 μm or less. It is desirable that the average particle size of the wax other than the fatty acid-based wax is within the above range because the transparency of the thermal recorder (1) tends to be further improved.

[0063] The content ratio of wax other than the fatty acid-based wax is preferably 0.1 mass% or more, more preferably 0.5 mass% or more, and even more preferably 1 mass% or more, with respect to 100 mass% of the dry mass of the thermal layer (4). In addition, the content ratio of wax other than the fatty acid-based wax is preferably 5 mass% or less, more preferably 4 mass% or less, and even more preferably 3 mass% or less, with respect to 100 mass% of the dry mass of the thermal layer (4). It is desirable that the content ratio of wax other than the fatty acid-based wax is within the above range, as this tends to further improve the transparency of the thermal recorder (1).

[0064] In the present embodiment, the types of wax contained in the thermal layer (4) are, for example, preferably 1 to 5 types, more preferably 1 to 2 types, and even more preferably 2 types. In addition, when the types of wax are 2 types, it is particularly preferable to contain one type each of fatty acid-based wax and polystyrene as the combination.

[0065] When the dry mass of the fatty acid-based wax is set to 1, the ratio of the dry mass of the wax other than the fatty acid-based wax (dry mass of the wax other than the fatty acid-based wax / dry mass of the fatty acid-based wax) is preferably 0.1 or higher, and more preferably 0.5 or higher. In addition, when the dry mass of the fatty acid-based wax is set to 1, the ratio of the dry mass of the wax other than the fatty acid-based wax (dry mass of the wax other than the fatty acid-based wax / dry mass of the fatty acid-based wax) is preferably 10 or lower, more preferably 5 or lower, and even more preferably 2 or lower. Furthermore, when the dry mass of the fatty acid-based wax is set to 1, the ratio of the dry mass of the wax other than the fatty acid-based wax (dry mass of the wax other than the fatty acid-based wax / dry mass of the fatty acid-based wax) is particularly preferably 1. It is desirable that the ratio of the dry mass of a wax other than the fatty acid-based wax to the dry mass of the fatty acid-based wax is within the above range, as this tends to improve the transparency and long-term water resistance of the thermal recorder (1).

[0066] The content ratio of the total amount of wax is preferably 0.2 mass% or more, more preferably 1 mass% or more, and even more preferably 1.5 mass% or more, with respect to 100 mass% of the dry mass of the thermal layer (4). Additionally, the content ratio of the total amount of wax is preferably 10 mass% or less, more preferably 8 mass% or less, and even more preferably 5 mass% or less, with respect to 100 mass% of the dry mass of the thermal layer (4). It is desirable that the content ratio of the total amount of wax is within the above range, as this tends to improve the transparency of the thermal recorder (1).

[0067] The above dyes include, for example, 3-dibutylamino-6-methyl-7-anilinofluorane, 3-(N-isobutyl-N-ethyl)amino-6-methyl-7-anilinofluorane, 3-(N-isopentyl-N-ethyl)amino-6-methyl-7-o-chloroanilinofluorane, 3-(N-ethyl-Np-toluidino)-6-methyl-7-anilinofluorane, 3-(N-ethyl-N-isopentyl)amino-6-methyl-7-anilinofluorane, 3-(N-ethoxypropyl-N-ethyl)amino-6-methyl-7-anilinofluorane, 3-(N-cyclohexyl-N-methyl)amino-6-methyl-7-anilinofluorane, 3-(N-methyl-Nn-propyl)amino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-p-toluidinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-8-methylfluorane, 3-diethylamino-7-(m-trifluoromethylanilino)fluorane, 3-diethylamino-7-(o-chloroanilino)fluorane, 3-diethylamino-7-chlorofluorane, 3-dibutylamino-6-methyl-7-bromofluorane, 3-dibutylamino-7-(o-chloroanilino)fluorane, 3-dipentylamino-6-methyl-7-anilinofluorane, 3-dimethylamino-5-methyl-7-methylfluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, crystal violet lactone, etc. may be used. These dyes may be used alone or in combination of two or more.

[0068] The average particle size of the dye is, for example, preferably 0.1 μm to 1.0 μm, more preferably 0.1 μm to 0.6 μm, even more preferably 0.1 μm to 0.55 μm, even more preferably 0.1 μm to 0.4 μm, and particularly preferably 0.1 μm to 0.3 μm. It is preferable that the average particle size of the dye be within the above range because the transparency of the thermal recorder (1) tends to be improved.

[0069] The content ratio of the above dye is preferably 5 mass% or more and 50 mass% or less with respect to 100 mass% of the dry mass of the above thermal layer (4), more preferably 8 mass% or more and 35 mass% or less, and even more preferably 10 mass% or more and 25 mass% or less.

[0070] The above-mentioned colorants include, for example, 4-hydroxyphenyl(4'-n-propoxyphenyl)sulfone, 3-[(3-phenylureido)phenyl]-4-methylbenzenesulfonate, N,N-di-[3-(p-toluenesulfonyloxy)phenyl]urea, 1,1-bis(p-hydroxyphenyl)cyclohexane, 1,1-bis(p-hydroxyphenyl)propane, 2,2-bis(p-hydroxyphenyl)propane, 2,2-bis(p-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 2,2'-methylenebis(4-chlorophenol), 2,2-bis(4-hydroxyphenyl)-4-methylpentane, 2,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxydiphenylsulfone, 4-hydroxy-4'-isopropoxydiphenylsulfone, 4-hydroxy-4'-methyldiphenylsulfone, 4-hydroxyphenyl-4'-benzyloxyphenylsulfone, 4-hydroxy-4´-allyloxydiphenylsulfone, bis(3-allyl-4-hydroxyphenyl)sulfone, poly(4-hydroxybenzoic acid), 4-benzyl hydroxybenzoate, 2,4-bis(phenylsulfonyl)phenol, α-{4-[(4-hydroxyphenyl)sulfonyl]phenyl}-ω-hydroxypoly (degree of polymerization n = 1 ∼ 7) (oxyethyleneoxyethyleneoxy-p-phenylenesulfonyl-p-phenylene)2,2-bis[(4-methyl-3-phenoxycarbonylaminophenyl)urea]diphenylsulfone, 3,5-bis(α-methylbenzyl)salicylic acid, Bis[4-(n-octyloxycarbonylamino)zinc salicylate], 4,4'-Bis(p-tolylsulfonylaminocarbonylamino)diphenylmethane, 4-hydroxybenzenesulfonanilide, 2'-(3-phenylureido)benzenesulfonanilide, N-(2-hydroxyphenyl)-2-[(4-hydroxyphenyl)thio]acetamide, N-(4-hydroxyphenyl)-2-[(4-hydroxyphenyl)thio]acetamide, 4-[[4-[4-[4-[[4-(1-methylethoxy)phenyl]sulfonylphenoxy]butoxy]phenyl]sulfonyl]phenol, 4-tert-butylphenol·formaldehyde polycondensate, N-(p-toluenesulfonyl)N'-(3-p-toluenesulfonyloxyphenyl)urea, 1-phenyl-3-(4-methylphenylsulfonyl)urea, etc., may be used. These developing agents may be used alone or in combination of two or more.

[0071] The average particle size of the above-mentioned developer is, for example, preferably 0.1 μm to 1.0 μm, more preferably 0.1 μm to 0.6 μm, even more preferably 0.1 μm to 0.55 μm, even more preferably 0.1 μm to 0.4 μm, and particularly preferably 0.1 μm to 0.3 μm. It is preferable that the average particle size of the above-mentioned developer is within the above range because the transparency of the thermal recorder (1) tends to be further improved.

[0072] The content ratio of the above-mentioned developer is preferably 20 mass% or more and 70 mass% or less with respect to 100 mass% of the dry mass of the above-mentioned thermal layer (4), more preferably 25 mass% or more and 60 mass% or less, and even more preferably 30 mass% or more and 50 mass% or less.

[0073] The above fillers may include, for example, kaolin, calcined kaolin, aluminum hydroxide, magnesium hydroxide, aluminum oxide, magnesium oxide, aluminum silicate, calcium carbonate, magnesium carbonate, titanium oxide, barium sulfate, silica gel, activated clay, talc, clay, diatomaceous earth, white carbon, zinc oxide, silicon oxide, colloidal silica, polystyrene resin particles, urea-formalin resin particles, polyolefin resin particles, etc. These fillers may be used individually or in combination of two or more types.

[0074] The average particle size of the above filler is, for example, preferably 0.1 μm to 1.0 μm, more preferably 0.1 μm to 0.6 μm, even more preferably 0.1 μm to 0.55 μm, even more preferably 0.1 μm to 0.4 μm, and particularly preferably 0.1 μm to 0.3 μm. It is preferable that the average particle size of the above filler is within the above range because the transparency of the thermal recorder (1) tends to be further improved.

[0075] The content ratio of the above filler is preferably 0.1 mass% or more and 30 mass% or less with respect to 100 mass% of the dry mass of the above thermal layer (4), more preferably 1 mass% or more and 20 mass% or less, and even more preferably 5 mass% or more and 15 mass% or less.

[0076] The above-mentioned binders include, for example, styrene-butadiene copolymer (SBR), polyvinyl alcohol, modified polyvinyl alcohol, starch, casein, gelatin, polyamide, polyacrylamide, modified polyacrylamide, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, hydroxypropylcellulose, polyvinyl acetate, polyacrylic acid ester, styrene-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer, diisobutylene-maleic anhydride copolymer, vinyl acetate-maleic anhydride copolymer, methylvinyl anhydride copolymer, isopropylene-maleic anhydride copolymer, styrene-butadiene copolymer, polyvinyl chloride, polyvinylidene chloride, vinyl chloride-vinyl acetate Copolymers, polyurethane, polystyrene, polyvinylpyrrolidone, acrylic acid esters, acrylonitrile, methyl vinyl ether, etc. may be used. These binders may be used alone or in combination of two or more types.

[0077] The content ratio of the above binder is preferably 5 mass% or more and 50 mass% or less with respect to 100 mass% of the dry mass of the thermal layer (4), more preferably 10 mass% or more and 40 mass% or less, and even more preferably 20 mass% or more and 30 mass% or less.

[0078] As the above-mentioned dispersant, a dispersant having a carboxyl group is preferred. As the above-mentioned dispersant having a carboxyl group, styrene-acrylic polymers such as styrene-acrylic acid (salt) polymers and styrene-acrylic acid ester polymers; styrene-maleic acid (salt) resins, styrene-maleic acid ester resins, etc. may be used. Among these, styrene-acrylic polymers are preferred, styrene-acrylic acid (salt) polymers are more preferred, and styrene-acrylic acid (ammonium salt) polymers are even more preferred. These dispersants may be used alone or in combination of two or more types.

[0079] The salt in the acrylate included in the dispersant having the above-mentioned carboxyl group is not particularly limited and may include, for example, ammonium salts such as ammonia; alkanolamine salts such as triethanolamine, diethanolamine, monoethanolamine; alkylamine salts such as methylamine, ethylamine, diethylamine, and triethylamine; polyamine salts such as diethyleneamine and diethylenetriamine; alkali metal salts such as lithium, sodium, and potassium; alkaline earth metal salts such as magnesium and calcium; and polyvalent metal salts such as zinc and iron. Among these, ammonium salts are particularly preferred.

[0080] The content ratio of the above dispersant is preferably 5 mass% or more and 30 mass% or less with respect to 100 mass% of the dry mass of the thermal layer (4), more preferably 7 mass% or more and 18 mass% or less, and even more preferably 10 mass% or more and 15 mass% or less.

[0081] As the above-mentioned crosslinking agent, for example, an epichlorohydrin-modified polyamide polyamine resin, an organic compound containing an oxazoline group, etc., may be used. These crosslinking agents may be used alone or in combination of two or more types.

[0082] The content ratio of the crosslinking agent is preferably 0.1 mass% or more and 10 mass% or less with respect to 100 mass% of the dry mass of the thermal layer (4), more preferably 0.3 mass% or more and 5 mass% or less, and even more preferably 0.5 mass% or more and 2 mass% or less.

[0083] When a dispersant having a carboxyl group is used as the above dispersant and an epichlorohydrin-modified polyamide-polyamine resin is used as the above crosslinking agent, in the above thermal layer (4), the azetidinium ring (AZR) in the epichlorohydrin-modified polyamide-polyamine resin, which is the crosslinking agent, reacts with the carboxyl group of the dispersant to form a crosslinked structure, and it is thought that the film-forming properties of the thermal layer (4) are improved by this crosslinked structure, and the voids contained in the thermal layer (4) are filled. As a result, since the transparency of the above thermal layer (4) is further improved, a thermal recorder (1) with superior transparency can be obtained.

[0084] In addition, when a dispersant having a carboxyl group is used as the above dispersant and an organic compound containing an oxazoline group is used as the above crosslinking agent, in the above thermal layer (4), the oxazoline group of the organic compound containing an oxazoline group, which is the crosslinking agent, reacts with the carboxyl group of the dispersant to form a crosslinking structure, and it is thought that the film-forming properties of the thermal layer (4) are improved by this crosslinking structure, and the voids contained in the thermal layer (4) are filled. As a result, since the transparency of the above thermal layer (4) is further improved, a thermal recorder (1) with superior transparency can be obtained.

[0085] The application amount (dry mass) of the above thermal layer (4) is, for example, preferably 0.5 g / m² 2 ~ 10.0 g / m² 2 is, and more preferably 1.0 g / m² 2 ~ 8.0 g / g / m 2 is, and more preferably 2.0 g / m2 ~ 6.0 g / g / m 2 is, and more preferably 3.0 g / m 2 ~ 6.0 g / m² 2 is, and more preferably 3.5 g / m 2 ~ 5.5 g / m² 2 is, and more preferably 4.0 g / m 2 ~ 5.0 g / m² 2 is, and particularly preferably 4.5 g / m² 2 It is desirable that the amount of coating is within the above range, as this tends to improve the transparency of the thermal recorder (1).

[0086] The thickness of the thermal layer (4) is, for example, preferably 2 μm to 6 μm, and more preferably 3 μm to 5 μm.

[0087] The thermal recording body (1) of the present embodiment has excellent transparency by having the above configuration.

[0088] For the thermal recording body (1) of the present embodiment, when the haze value of a laminate having the substrate (2) and the thermal layer (4) as end surfaces is measured by the method described in the example, it is preferably 40% or less, more preferably 38% or less, and even more preferably 37% or less. It is preferable that the haze value of the laminate having the substrate (2) and the thermal layer (4) as end surfaces be within the above range because the transparency is superior.

[0089] [Method for manufacturing a thermal recorder]

[0090] The method for manufacturing a thermal recorder according to the present invention is not particularly limited. For example, a thermal layer paint can be prepared by a known or conventional method by dispersing a component included in the thermal layer in a solvent such as water, then applying the obtained paint by a known or conventional method, and then drying by a known or conventional method.

[0091] (Preparation process)

[0092] In the preparation process, the thermal layer paint may be prepared by pre-dispersing all components in the same solvent. Alternatively, a colorant and a developer that react with each other may be prepared as separate dispersions, and then the two may be mixed to form the thermal layer paint. At that time, other components may be added to either the dispersion containing the dye or the dispersion containing the developer, or to both. The method of preparing the paint is not particularly limited and may include, for example, stirring, ultrasonic treatment, a ball mill, a bead mill, a sand mill, or a crushing treatment using a high-pressure homogenizer. These methods may be used individually or in combination of two or more types.

[0093] In the method for manufacturing a thermal recorder according to the present invention, it is preferable to include a process for preparing a thermal layer paint using a solubilized fatty acid-based wax and / or an emulsion-type fatty acid-based wax in order to further improve the transparency of the thermal recorder. Among these, it is more preferable to include a process for preparing a thermal layer paint using a solubilized fatty acid-based wax. By finely atomizing or solubilizing the fatty acid-based wax into an emulsion-type, the penetration of the fatty acid-based wax into the voids between particles of other components is further improved, and since the voids are further sealed, diffuse reflection of light in the voids is further suppressed, and as a result, it is presumed that the transparency of the thermal recorder is further improved.

[0094] The method for obtaining the above-mentioned solubilized fatty acid-based wax is not particularly limited and, for example, can be obtained by adding a solubilizing agent to the fatty acid-based wax and mixing. Regarding the above-mentioned solubilizing agent, all of the contents described in the [Thermal Recorder] section may be used. Furthermore, the method of mixing is not particularly limited and may include, for example, stirring, ultrasonic treatment, a ball mill, a bead mill, a sand mill, a crushing treatment using a high-pressure homogenizer, etc. These methods may be used individually or in combination of two or more types.

[0095] It is preferable that the above-mentioned solubilized fatty acid-based wax be a transparent liquid. For example, a transparent liquid solubilized fatty acid-based wax can be prepared by mixing the above-mentioned fatty acid-based wax with the above-mentioned solubilizing agent. Since such a solubilized fatty acid-based wax can further improve penetration into a thermal layer or a coating for a thermal layer, the transparency of the thermal recorder can be further improved. In addition, unlike an emulsion in which the wax exists as particles in the medium, this solubilized fatty acid-based wax does not have the wax existing as particles, so the transparency of the thermal recorder can be further improved.

[0096] (Coating process)

[0097] In the coating process, the method of applying the thermal layer coating obtained above may include applying it directly to the substrate or applying it to a release liner or the like and then transferring it to the substrate. The coating method is not particularly limited and may include, for example, air knife coating, verba blade coating, pure blade coating, rod blade coating, shot well coating, curtain coating, die coating, gravure coating, etc. In addition, these methods may be used individually or in combination of two or more types.

[0098] (Drying process)

[0099] The method of drying the paint applied above is not particularly limited and may include, for example, heat drying, room temperature drying, vacuum drying, etc. A thermal layer can be formed by drying the applied paint by these methods. In addition, these methods may be used individually or in combination of two or more types.

[0100] When the thermal recorder of the present invention has a layer other than the thermal layer, the above description may be applied as a method for forming the other layer. For example, as shown in FIG. 1, a method for manufacturing a thermal recorder (1) having a substrate (2), an anchor layer (3), and a thermal layer (4) in this order may be manufactured by forming an anchor layer (3) on the substrate (2) and then forming a thermal layer (4) on the anchor layer (3). As a method for preparing the paint for the anchor layer, each component included in the anchor layer (3) may be prepared by dispersing all of them in the same solvent beforehand, or if the components that react with each other are included, each component may be prepared as a separate dispersion and then mixed to prepare. The above preparation method is not particularly limited and may include, for example, stirring, ultrasonic treatment, a ball mill, a bead mill, a sand mill, a crushing treatment using a high-pressure homogenizer, etc. These methods can be used individually or in combination of two or more types. As a method for applying the anchor layer paint obtained above to the substrate (2), for example, a method of applying it directly onto the substrate (2) can be used. The method of applying the anchor layer paint is not particularly limited and may include, for example, air knife coating, verba blade coating, pure blade coating, rod blade coating, shot well coating, curtain coating, die coating, gravure coating, etc. Additionally, these methods can be used individually or in combination of two or more types. Subsequently, an anchor layer (3) can be formed on the substrate (2) by drying the anchor layer paint applied above. Examples of the drying methods include heat drying, room temperature drying, vacuum drying, etc. Additionally, these methods can be used individually or in combination of two or more types. Subsequently, a thermal layer (4) can be formed on the anchor layer (3) in the same order as above to obtain the thermal recorder (1) shown in FIG. 1.

[0101] In the method for manufacturing a thermal recorder according to the present invention, each layer may be applied simultaneously in multiple layers, for example by a curtain coater, or formed sequentially individually. Additionally, some layers may be applied simultaneously, and some layers may be formed sequentially individually.

[0102] Examples

[0103] The present invention will be explained more specifically below by way of examples, but the present invention is not limited by these examples, but is limited only by the description in the claims.

[0104] A thermal recorder having an anchor layer and a thermal layer laminated in this order on a substrate was manufactured by the following process.

[0105] (Example 1)

[0106] (Manufacture of thermal recorders)

[0107] <Anchor Layer>

[0108] An anchor layer coating was prepared by adding water to a modified styrene-acrylic acid (ammonium salt)-based resin (manufactured by BASF Japan Co., Ltd., product name: Johnkrill PDX7430) such that the dry mass was 10 mass%. The anchor layer coating was applied onto a biaxially stretched polypropylene (OPP) film (thickness: 40 μm) used as a substrate and subsequently dried, so that the coating amount was 0.5 to 2.0 g / m² as a dry mass. 2 An anchor layer with a thickness of 0.5 to 2 μm was formed.

[0109] <Thermal Layer>

[0110] A thermal layer paint prepared using water as a solvent at a dry mass of 23 mass%, such that the dry mass of each compounding material has the composition shown in Table 1, is applied onto the anchor layer and subsequently dried at 50°C, thereby achieving a coating amount of 4.0 g / m² as a dry mass. 2A thermal layer was formed, and the thermal recorder of Example 1 was manufactured. In addition, in Table 1, the values ​​of each compounding material represent the ratio of mass after drying (dry mass). Furthermore, unless otherwise specified, if the compounding material (fatty acid-based wax, etc.) contains a surfactant or a solvent, the values ​​of each compounding material in Table 1 represent the ratio of mass at the time of drying including the surfactant or the solvent.

[0111] In addition, as a compounding material, Wax 1 used was a solubilized fatty acid-based wax (manufactured by Nissin Chemical Research Institute, Inc., product name: R-053D). In addition, Wax 1 contained a fatty acid-based wax as a main component, an anionic surfactant and a polyoxyethylene alkyl ether as surfactants, and water as a solvent. In addition, Wax 1 was well soluble in water. In addition, the dye used was 3-dibutylamino-6-methyl-7-anilinofluorane with an average particle size of 0.15 μm, the developer used was 4-hydroxyphenyl(4'-n-propoxyphenyl)sulfone (manufactured by Mitsubishi Chemical Corporation, trade name: Tomilac KN) with an average particle size of 0.15 μm, the filler used was kaolin with an average particle size of 0.4 μm, the binder used was SBR with a glass transition temperature (Tg) of "-3 ℃", the dispersant used was a styrene-acrylic acid (ammonium salt)-based polymer, and the crosslinking agent used was an epichlorohydrin-modified polyamide-polyamine resin.

[0112] (Example 2)

[0113] A thermal recording body of Example 2 was prepared in the same manner as Example 1, except that in the thermal layer, wax 5 (polystyrene wax with an average particle size of 0.2 μm) was used as a wax other than fatty acid-based wax, and the amount of each compounding material was adjusted so that the dry mass of each compounding material was the composition shown in Table 1.

[0114] (Example 3)

[0115] A thermal recorder of Example 3 was prepared in the same manner as in Example 2, except that in the thermal layer, Wax 1 was changed to a fatty acid-based wax in the emulsion form of Wax 2 (manufactured by Chukyo Yuji Co., Ltd., trade name: Himicron L-271). Furthermore, Wax 2 contained 20 mass% to 30 mass% of fatty acid amide by dry mass as a main component, contained less than 1.0 mass% of triethanolamine by dry mass as a solvent, and contained water as a solvent. Additionally, Wax 2 was dispersible in water. Furthermore, the average particle size of the fine particles contained in the emulsion of Wax 2 was measured to be 0.87 μm.

[0116] (Example 4)

[0117] A thermal recorder of Example 4 was prepared in the same manner as in Example 2, except that in the thermal layer, Wax 1 was changed to a fatty acid-based wax in the emulsion form of Wax 3 (manufactured by Nissin Chemical Research Institute, Inc., product name: New Wax E-50). Furthermore, Wax 3 contained a fatty acid-based wax as a main component, solid paraffin as an other component in a dry mass of 10 mass% to 20 mass%, and water as a solvent. Additionally, Wax 3 was dispersible in water. Furthermore, the average particle size of the fine particles contained in the emulsion of Wax 3 was measured to be 0.18 μm.

[0118] (Example 5)

[0119] A thermal recorder of Example 5 was prepared in the same manner as in Example 2, except that in the thermal layer, Wax 1 was changed to Wax 4, a solubilized fatty acid-based wax. Wax 4 was prepared by adding 3 g of diethylene glycol monobutyl ether as a solvent to 1 g of solid obtained by heating the emulsion-phase fatty acid-based wax of Wax 3 (manufactured by Nissin Chemical Research Institute, Trade Name: New Wax E-50) to 50°C and distilling off the water, and this was used as a solubilized fatty acid-based wax. Furthermore, in Example 5, since the diethylene glycol butyl ether is treated as a solvent to solubilize the fatty acid-based wax, the value of Wax 4 in Example 5 of Table 1 represents the ratio of dry mass including the diethylene glycol butyl ether.

[0120] The above wax 1 and the above wax 4 were transparent liquids.

[0121] (Comparative Example 1)

[0122] A thermal recorder of Comparative Example 1 was prepared in the same manner as in Example 2 above, except that in the thermal layer, wax 1 was changed to wax 6 and wax 5 was changed to wax 7. In addition, the wax 6 used polyethylene wax with an average particle size of 1.3 μm, and the wax 7 used paraffin with a melting point of 46 °C and an average particle size of 0.3 μm.

[0123] By the above method, the thermal recorders of Examples 1 to 5 and Comparative Example 1 were prepared and used for measuring the haze values ​​below.

[0124] (Measurement of haze value)

[0125] In measuring the haze value, the haze value of each thermal recorder was measured by using a haze meter (manufactured by Nippon Denk Co., Ltd., product name: NDH7000) and measuring from the thermal layer side of the thermal recorder (a laminate having a substrate and a thermal layer as both ends) manufactured above. The results of the obtained haze values ​​for each thermal recorder manufactured in each example and each comparative example are shown in Table 1.

[0126] The above measurements were performed according to the method of JIS K7136:2000.

[0127]

[0128] From Table 1, the following could be confirmed.

[0129] The thermal recorders of Examples 1 to 5, which contain fatty acid-based wax as the wax in the thermal layer, had smaller haze values ​​than the thermal recorder of Comparative Example 1, which does not contain fatty acid-based wax; thus, it was confirmed that using fatty acid-based wax as the wax improves the transparency of the thermal recorder. In addition, compared to the thermal recorder of Example 4, which is obtained by using Wax 3, an emulsion-type fatty acid-based wax, the thermal recorder of Example 5, which is obtained by solubilizing Wax 3 with a solvent to form a solubilized fatty acid-based wax, had smaller haze values ​​and improved transparency. Although the detailed mechanism of action for the improvement in transparency caused by using the fatty acid-based wax after solubilization is unclear, it is presumed that this is because the penetration into the pores between the particles of the compounding material was further improved by solubilizing Wax 3, which existed as particles of a size visible to the naked eye.

[0130] As a summary of the above, the configuration of the present invention and its variations are described below.

[0131] [Note 1] A thermal recorder having a thermal layer containing fatty acid-based wax.

[0132] [Note 2] The above fatty acid-based wax is a thermal recorder described in Note 1, which is a solubilized fatty acid-based wax and / or an emulsion-type fatty acid-based wax.

[0133] [Note 3] The above fatty acid-based wax is a solubilized fatty acid-based wax, a thermal recording material described in any one of Notes 1 to 2.

[0134] [Note 4] The above-mentioned solubilized fatty acid-based wax is a thermal recording body described in any one of Notes 2 to 3, containing a solubilizing agent.

[0135] [Note 5] The above-mentioned solubilized fatty acid-based wax is a transparent liquid and is a thermal recording material described in any one of Notes 1 to 4.

[0136] [Note 6] The thermal layer described above is a thermal recorder described in any one of Notes 1 to 5, containing a surfactant and / or a solvent.

[0137] [Note 7] The thermal layer described in any one of Notes 1 to 6 is a heat-sensitive body that is additionally a wax other than the fatty acid-based wax and also contains a wax having an average particle size of 1 μm or less.

[0138] [Note 8] A heat-sensitive material described in Note 7, the wax other than the fatty acid-based wax described above is one or more of polystyrene, polyethylene, and paraffin.

[0139] [Note 9] A thermal recording body described in any one of Notes 1 to 8, wherein the content ratio of the fatty acid-based wax is 0.1 mass% or more and 5 mass% or less with respect to 100 mass% of the dry mass of the thermal layer.

[0140] [Note 10] A method for manufacturing a thermal recording body as described in any one of Notes 1 to 9, comprising the steps of: preparing a paint for a thermal layer using a solubilized fatty acid-based wax and / or an emulsion-type fatty acid-based wax; and forming a thermal layer by applying and drying the paint for a thermal layer.

[0141] [Note 11] A method for manufacturing a thermal recording body as described in any one of Notes 1 to 9, comprising a process of preparing a paint for a thermal layer using a transparent liquid solubilized fatty acid-based wax, and a process of forming a thermal layer by applying and drying the paint for the thermal layer.

[0142] Industrial applicability

[0143] Since the thermal recording body of the present invention has excellent transparency, it can be particularly advantageously used in applications where visibility of the contents is required, such as labels for food containers like lunch boxes or food packaging films. Explanation of the symbols

[0144] 1 : Thermal recorder 2 : Entry 3 : Anchor layer 4: Thermal layer

Claims

Claim 1 A thermal recording device comprising a substrate which is a transparent synthetic resin film and a thermal layer containing a solubilized fatty acid-based wax. Claim 2 In claim 1, the solubilized fatty acid-based wax is a thermal recording body containing a solubilizing agent. Claim 3 In claim 1, the solubilized fatty acid-based wax is a transparent liquid thermal recorder. Claim 4 A thermal recording body according to claim 1, wherein the average particle size of the solubilized fatty acid-based wax is 1.0 μm or less. Claim 5 In any one of claims 1 to 4, the thermal layer is a thermal recorder containing a surfactant and / or a solvent. Claim 6 A thermal recording body according to any one of claims 1 to 4, wherein the thermal layer is additionally a wax other than the solubilized fatty acid-based wax and also contains a wax having an average particle size of 1 μm or less. Claim 7 A thermal recording body according to claim 6, wherein the average particle size of the wax other than the solubilized fatty acid-based wax is 0.6 μm or less. Claim 8 A thermal recording body according to any one of claims 1 to 4, wherein the content ratio of the solubilized fatty acid-based wax is 0.1 mass% or more and 5 mass% or less with respect to 100 mass% of the dry mass of the thermal layer. Claim 9 A method for manufacturing a thermal recording body as described in any one of claims 1 to 4, comprising a process of preparing a paint for a thermal layer using a solubilized fatty acid-based wax, and a process of forming a thermal layer by applying and drying the paint for the thermal layer.

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