Recording medium and exterior member

Abstract

A recording medium according to one embodiment of this disclosure is provided with a recording layer containing a leuco dye as a color-developing compound; a first barrier film that is disposed on a first surface and a second surface of the recording layer, the second surface being opposite the first surface, in order to suppress intrusion of moisture and / or oxygen; and a second barrier film that is chemical resistant and is disposed so as to extend continuously over a lateral surface of the recording layer, at least from a peripheral section of the first surface to a peripheral section of the second surface of the recording layer.

Description

Technical Field

[0001] The present disclosure relates to a recording medium having one or more recording layers and an exterior member including the same.

Background Art

[0002] For example, Patent Document 1 discloses a reversible thermosensitive recording medium in which the front and back surfaces of a core film onto which island-shaped reversible thermosensitive recording portions are transferred are each protected by an overlay film.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] By the way, the above-described recording medium can be used as an exterior member. When the recording medium is used as an exterior member of, for example, an electronic device, durability and high designability that do not impair the appearance of the electronic device are required. In particular, in the end portion structure of the recording medium, durability and designability often trade off with each other, and compatibility between them is desired.

[0005]

[0006] A recording medium according to an embodiment of the present disclosure includes a recording layer containing a leuco dye as a color-forming compound, a first barrier film provided on one surface of the recording layer and the other surface facing the one surface to suppress the incorporation of at least one of moisture and oxygen, and a second barrier film having chemical resistance and continuously provided on the side surface of the recording layer from the peripheral portion of at least one surface of the recording layer to the peripheral portion of the other surface. Further, the second barrier film contains an ultraviolet curable resin, and the ultraviolet curable resin is an organic-inorganic hybrid material. The organic-inorganic hybrid material has a silsesquioxane skeleton represented by the compositional formula [(RSiO 1.5 )n . 。

[0007] The exterior member according to an embodiment of the present disclosure includes at least a support substrate provided with a recording medium, and this recording medium has the same components as the recording medium of the above-described embodiment of the present disclosure.

[0008] In the reversible recording medium and the exterior member according to an embodiment of the present disclosure, a first barrier film for suppressing the intrusion of at least one of moisture and oxygen is provided on one surface and the opposing other surface of the recording layer, and further, a second barrier film having chemical resistance is continuously provided on the side surface of the recording layer from the side surface of the recording layer and the peripheral portion of one surface of the recording layer to the peripheral portion of the other surface. The second barrier film contains an ultraviolet curable resin, and the ultraviolet curable resin is an organic-inorganic hybrid material. The organic-inorganic hybrid material has a silsesquioxane skeleton represented by the compositional formula [(RSiO 1.5 ) n . 。This suppresses the intrusion of environmental contaminants into the recording layer and reduces the non-display area at the outer edge of the recording layer.

Brief Description of the Drawings

[0009]

Figure 1A

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Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The following description is a specific example of the present disclosure, and the present disclosure is not limited to the following aspects. Also, the present disclosure is not limited to the arrangement, dimensions, dimensional ratios, etc. of each component shown in each figure. The order of description is as follows. 1. Embodiment (Recording medium in which the side surface of the recording layer is covered with a barrier film having chemical resistance) 1-1. Configuration of the recording medium 1-2. Manufacturing method of the recording medium 1-3. Recording and erasing methods of the recording medium 1-4. Function and effect 2. Modification example 2-1. Modification Example 1 (Example in which the side surface is an inclined surface) 2-2. Modified Example 2 (Example with an additional hard coat layer) 2-3. Modified Example 3 (Example where the entire recording layer is covered with a chemical-resistant barrier film) 2-4. Modified Example 4 (Example where multiple recording layers are stacked) 2-5. Modified Example 5 (Example where the recording layer contains multiple types of color-forming compounds) 3. Application Examples 4. Examples

[0011] <1. Embodiment> FIG. 1A schematically shows an example of the cross-sectional structure of a recording medium (recording medium 1) according to an embodiment of the present disclosure. FIG. 1B schematically shows an example of the planar structure of the recording medium 1 shown in FIG. 1A. FIG. 1A shows a cross-section along the line I-I shown in FIG. 1B. The recording medium 1 is a recording medium capable of reversibly or irreversibly recording and erasing information by heat, and is used, for example, in the printing part of an Integrated Circuit (IC) card, a wearable terminal such as a wristwatch, or the decoration of an automobile.

[0012] (1-1. Configuration of the recording medium) On the front surface (surface S1) and the back surface (surface S2) of the recording layer 11 of the recording medium 1, first barrier films 14 and 15 are provided via adhesive layers 12 and 13, respectively. In other words, the recording medium 1 has a configuration in which, for example, the first barrier film 14, the adhesive layer 12, the recording layer 11, the adhesive layer 13, and the first barrier film 15 are laminated in this order. In the recording medium 1 of the present embodiment, a second barrier film 16 is further provided on the side surface S3 of the recording layer 11 including the adhesive layers 12 and 13 and the first barrier films 14 and 15. This second barrier film 16 has chemical resistance, and specifically, as shown in FIGS. 1A and 1B, for example, with respect to the four side surfaces (surface S3) of the recording layer 11 having a rectangular shape, for example, from the peripheral edge of the surface (surface S1, precisely, the first barrier film 15 provided on the surface (surface S1) side of the recording layer 11) of the recording layer 11 to the peripheral edge of the back surface (surface S2, precisely, the first barrier film 14 provided on the back surface (surface S2) side of the recording layer 11) of the recording layer 11, it is continuously provided.

[0013] The recording layer 11 is capable of reversibly or irreversibly recording and erasing information by heat. The recording layer 11 of the present embodiment is configured using, for example, a material that can control a decolorized state and a colored state and enables stable repeated recording. Specifically, the recording layer 11 is formed by dispersing, for example, a color-forming compound, a color-developing / diminishing agent, and a photothermal conversion agent in a polymer material, for example. The film thickness of the recording layer 11 (hereinafter simply referred to as thickness) is, for example, 1 μm or more and 10 μm or less.

[0014] As the color-forming compound, for example, a leuco dye is used. Examples of the leuco dye include existing dyes for thermal paper. Specifically, as an example, a compound shown in the following formula (6) and containing, for example, a group having electron-donating properties in the molecule can be mentioned.

[0015]

Chemical formula

[0016] The color-forming compound is not particularly limited and can be appropriately selected according to the purpose. Specific color-forming compounds include, in addition to the compounds represented by the above formula (6), for example, fluoran compounds, triphenylmethane phthalide compounds, azaphthalide compounds, phenothiazine compounds, leucoauramine compounds, and indolinophthalide compounds. In addition, for example, 2-anilino-3-methyl-6-diethylaminofluorane, 2-anilino-3-methyl-6-di(n-butylamino)fluorane, 2-anilino-3-methyl-6-(N-n-propyl-N-methylamino)fluorane, 2-anilino-3-methyl-6-(N-isopropyl-N-methylamino)fluorane, 2-anilino-3-methyl-6-(N-isobutyl-N-methylamino)fluorane, 2-anilino-3-methyl-6-(N-n-amyl-N-methylamino)fluorane, 2-anilino-3-methyl-6-(N-sec-butyl-N-methylamino)fluorane, 2-anilino-3-methyl-6-(N-n-amyl-N-ethylamino)fluorane, 2-anilino-3-methyl-6-(N-iso-amyl-N-ethylamino)fluorane, 2-anilino-3-methyl-6-(N-n-propyl-N-isopropylamino)fluorane, 2-anilino-3-methyl-6-(N-cyclohexyl-N-methylamino)fluorane, 2-anilino-3-methyl-6-(N-ethyl-p-toluidino)fluorane, 2-anilino-3-methyl-6-(N-methyl-p-toluidino)fluorane, 2-(m-trichloromethylanilino)-3-methyl-6-diethylaminofluorane, 2-(m-trifluoromethylanilino)-3-methyl-6-diethylaminofluorane, 2-(m-trichloromethylanilino)-3-methyl-6-(N-cyclohexyl-N-methylamino)fluorane, 2-(2,4-(Dimethylamino)-3-methyl-6-(diethylamino)fluoran, 2-(N-ethyl-p-toluidino)-3-methyl-6-(N-ethylanilino)fluoran, 2-(N-ethyl-p-toluidino)-3-methyl-6-(N-propyl-p-toluidino)fluoran, 2-anilino-6-(N-n-hexyl-N-ethylamino)fluoran, 2-(o-chloroanilino)-6-(diethylamino)fluoran, 2-(o-chloroanilino)-6-(dibutylamino)fluoran, 2-(m-trifluoromethylanilino)-6-(diethylamino)fluoran, 2,3-dimethyl-6-(dimethylamino)fluoran, 3-methyl-6-(N-ethyl-p-toluidino)fluoran, 2-chloro-6-(diethylamino)fluoran, 2-bromo-6-(diethylamino)fluoran, 2-chloro-6-(dipropylamino)fluoran, 3-chloro-6-(cyclohexylamino)fluoran, 3-bromo-6-(cyclohexylamino)fluoran, 2-chloro-6-(N-ethyl-N-isoamylamino)fluoran, 2-chloro-3-methyl-6-(diethylamino)fluoran, 2-anilino-3-chloro-6-(diethylamino)fluoran, 2-(o-chloroanilino)-3-chloro-6-(cyclohexylamino)fluoran, 2-(m-trifluoromethylanilino)-3-chloro-6-(diethylamino)fluoran, 2-(2,3-dichloroanilino)-3-chloro-6-(diethylamino)fluoran, 1,2-Benzoyl-6-diethylaminofluorane, 3-Diethylamino-6-(m-trifluoromethylanilino)fluorane, 3-(1-Ethyl-2-methylindol-3-yl)-3-(2-ethoxy-4-diethylaminophenyl)-4-azaphthalide, 3-(1-Ethyl-2-methylindol-3-yl)-3-(2-ethoxy-4-diethylaminophenyl)-7-azaphthalide, 3-(1-Octyl-2-methylindol-3-yl)-3-(2-ethoxy-4-diethylaminophenyl)-4-azaphthalide, 3-(1-Ethyl-2-methylindol-3-yl)-3-(2-methyl-4-diethylaminophenyl)-4-azaphthalide, 3-(1-Ethyl-2-methylindol-3-yl)-3-(2-methyl-4-diethylaminophenyl)-7-azaphthalide, 3-(1-Ethyl-2-methylindol-3-yl)-3-(4-diethylaminophenyl)-4-azaphthalide, 3-(1-Ethyl-2-methylindol-3-yl)-3-(4-N-n-amyl-N-methylaminophenyl)-4-azaphthalide, 3-(1-Methyl-2-methylindol-3-yl)-3-(2-hexyloxy-4-diethylaminophenyl)-4-azaphthalide, 3,3-Bis(2-ethoxy-4-diethylaminophenyl)-4-azaphthalide, 3,3-Bis(2-ethoxy-4-diethylaminophenyl)-7-azaphthalide, 2-(p-Acetylanilino)-6-(N-n-amyl-N-n-butylamino)fluorane, 2-Benzylamino-6-(N-ethyl-p-toluidino)fluorane, 2-Benzylamino-6-(N-methyl-2,4-dimethylanilino)fluorane, 2-Benzylamino-6-(N-ethyl-2,4 - Dimethylamino) fluoran, 2 - Benzylamino - 6 - (N - methyl - p - toluidino) fluoran, 2 - Benzylamino - 6 - (N - ethyl - p - toluidino) fluoran, 2 - (Di - p - methylbenzylamino) - 6 - (N - ethyl - p - toluidino) fluoran, 2 - (α - Phenylethylamino) - 6 - (N - ethyl - p - toluidino) fluoran, 2 - Methylamino - 6 - (N - methylanilino) fluoran, 2 - Methylamino - 6 - (N - ethylanilino) fluoran, 2 - Methylamino - 6 - (N - propylanilino) fluoran, 2 - Ethylamino - 6 - (N - methyl - p - toluidino) fluoran, 2 - Methylamino - 6 - (N - methyl - 2,4 - dimethylanilino) fluoran, 2 - Ethylamino - 6 - (N - ethyl - 2,4 - dimethylanilino) fluoran, 2 - Dimethylamino - 6 - (N - methylanilino) fluoran, 2 - Dimethylamino - 6 - (N - ethylanilino) fluoran, 2 - Diethylamino - 6 - (N - methyl - p - toluidino) fluoran, 2 - Diethylamino - 6 - (N - ethyl - p - toluidino) fluoran, 2 - Dipropylamino - 6 - (N - methylanilino) fluoran, 2 - Dipropylamino - 6 - (N - ethylanilino) fluoran, 2 - Amino - 6 - (N - methylanilino) fluoran, 2 - Amino - 6 - (N - ethylanilino) fluoran, 2 - Amino - 6 - (N - propylanilino) fluoran, 2 - Amino - 6 - (N - methyl - p - toluidino) fluoran, 2 - Amino - 6 - (N - ethyl - p - toluidino) fluoran, 2 - Amino - 6 - (N - propyl - p - toluidino) fluoran, 2 - Amino - 6 - (N - methyl - p - ethylanilino) fluoran, 2 - Amino - 6 - (N - ethyl - p - ethylanilino) fluoran, 2 - Amino - 6 - (N - propyl - p - ethylanilino) fluoran, 2 - Amino - 6 - (N - methyl - 2,4 - dimethylanilino) fluoran, 2 - Amino - 6 - (N - ethyl - 2,4 - dimethylanilino) fluoran, 2 - Amino - 6 - (N - propyl - 2,4 - dimethylanilino) fluoran, 2 - Amino - 6 - (N - methyl - p - chloroanilino) fluoran, 2 - Amino - 6 - (N - ethyl - p - chloroanilino) fluoran, 2 - Amino - 6 - (N - propyl - p - chloroanilino) fluoran, 1,Examples include 2 - benzo - 6-(N - ethyl - N - isoamylamino) fluoran, 1,2 - benzo - 6 - dibutylamino fluoran, 1,2 - benzo - 6-(N - methyl - N - cyclohexylamino) fluoran, and 1,2 - benzo - 6-(N - ethyl - N - toluidino) fluoran. In the recording layer 11, the above - mentioned compound may be used alone as the color - forming compound, or two or more thereof may be used in combination.,

[0017] The color - developing / color - fading agent is for example for developing a colorless color - forming compound or for fading a color - forming compound showing a predetermined color. Examples of the color - developing / color - fading agent include phenol derivatives, salicylic acid derivatives, and urea derivatives. Specifically, for example, compounds having a salicylic acid skeleton represented by the following general formula (7) and containing an electron - accepting group in the molecule can be mentioned.,

[0018] [Chemical formula] (X is any one of - NHCO -, - CONH -, - NHCONH -, - CONHCO -, - NHNHCO -, - CONHNH -, - CONHNHCO -, - NHCOCONH -, - NHCONHCO -, - CONHCONH -, - NHNHCONH -, - NHCONHNH -, - CONHNHCONH -, - NHCONHNHCO -, - CONHNHCONH -. R is a linear hydrocarbon group having 25 or more and 34 or less carbon atoms.)

[0019] Examples of the developer and color reducer include, among others, 4,4'-isopropylidene bisphenol, 4,4'-isopropylidene bis(o-methylphenol), 4,4'-sec-butylidene bisphenol, 4,4'-isopropylidene bis(2-tert-butylphenol), zinc p-nitrobenzoate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid, 2,2-(3,4'-dihydroxydiphenyl) propane, bis(4-hydroxy-3-methylphenyl) sulfide, 4-{β-(p-methoxyphenoxy) ethoxy} salicylic acid, 1,7-bis(4-hydroxyphenylthio)-3,5-dioxaheptane, 1,5-bis(4-hydroxyphenylthio)-5-oxapentane, monobenzyl phthalate monocalcium salt, 4,4'-cyclohexylidene diphenol, 4,4'-isopropylidene bis(2-chlorophenol), 2,2'-methylene bis(4-methyl-6-tert-butylphenol), 4,4'-butylidene bis(6-tert-butyl-2-methyl) phenol, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,1,3-tris(2-methyl-4-hydroxy-5-cyclohexylphenyl) butane, 4,4'-thiobis(6-tert-butyl-2-methyl) phenol, 4,4'-diphenol sulfone, 4-isopropoxy-4'-hydroxydiphenyl sulfone (4-hydroxy-4'-isopropoxydiphenyl sulfone), 4-benzyloxy-4'-hydroxydiphenyl sulfone, 4,4'-diphenol sulfoxide, isopropyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, benzyl protocatechuate, stearyl gallate, lauryl gallate, octyl gallate, 1,3-bis(4-hydroxyphenylthio)-propane, N,N'-diphenylthiourea, N,N'-di(m-chlorophenyl)thiourea, salicylanilide, methyl bis(4-hydroxyphenyl) acetate, benzyl bis(4-hydroxyphenyl) acetate, 1,3-bis(4-hydroxychumyl) benzene, 1,4-bis(4-hydroxychumyl) benzene, 2,4'-diphenol sulfone, 2,2'-diallyl-4,4'-diphenol sulfone, 3,4-dihydroxyphenyl-4'-methyldiphenyl sulfone, zinc 1-acetoxy-2-naphthoate, zinc 2-acetoxy-1-naphthoate, zinc 2-acetoxy-3-naphthoate, α,α-bis(4-hydroxyphenyl)-α-methyltoluene, antipyrine complex of zinc thiocyanate, tetrabromobisphenol A, tetrabromobisphenol S, 4,4'-thiobis(2-methylphenol), 4,4'-thiobis(2-chlorophenol), dodecylphosphonic acid, tetradecylphosphonic acid, hexadecylphosphonic acid, octadecylphosphonic acid, eicosylphosphonic acid, docosylphosphonic acid, tetracosylphosphonic acid, hexacosylphosphonic acid, octacosylphosphonic acid, α-hydroxydodecylphosphonic acid, α-hydroxytetradecylphosphonic acid, α-hydroxyhexadecylphosphonic acid, α-hydroxyoctadecylphosphonic acid, α-hydroxyeicosylphosphonic acid, α-hydroxydocosylphosphonic acid, α-hydroxytetracosylphosphonic acid, dihexadecyl phosphate, dioctadecyl phosphate, dieicosyl phosphate, didocosyl phosphate, monohexadecyl phosphate, monooctadecyl phosphate, monoicosyl phosphate, monodocosyl phosphate, methylhexadecyl phosphate, methyloctadecyl phosphate, methyleicosyl phosphate, methyldocosyl phosphate, amylhexadecyl phosphate, octylhexadecyl phosphate and laurylhexadecyl phosphate, etc. may be mentioned. In the recording layer 11, the above compound may be used alone as a developer / fading inhibitor, or in combination of two or more kinds.,

[0020] The photothermal conversion agent absorbs light in a predetermined wavelength range in the near-infrared region, for example, and generates heat. As the photothermal conversion agent, it is preferable to use a near-infrared absorbing dye that has an absorption peak in the range of 700 nm or more and 2000 nm or less in wavelength and has almost no absorption in the visible region. Specifically, for example, compounds having a phthalocyanine skeleton (phthalocyanine-based dyes), compounds having a naphthalocyanine skeleton (naphthalocyanine-based dyes), compounds having a squarylium skeleton (squarylium-based dyes), metal complexes such as dithio complexes, diimonium salts, aminium salts, and inorganic compounds can be mentioned. Examples of the inorganic compounds include graphite, carbon black, metal powder particles, cobalt tetroxide, iron oxide, chromium oxide, copper oxide, metal oxides such as titanium black and ITO, metal nitrides such as niobium nitride, metal carbides such as tantalum carbide, metal sulfides, or various magnetic powders. In addition, a compound having a cyanine skeleton (cyanine-based dye) having excellent light resistance and heat resistance may be used.

[0021] Note that excellent light resistance means not decomposing during laser irradiation. Excellent heat resistance means that, for example, when formed into a film together with a polymer material and stored at 150 °C for 30 minutes, for example, there is no change of 20% or more in the maximum absorption peak value of the absorption spectrum. Examples of such compounds having a cyanine skeleton include those having at least one of a counter ion selected from SbF6, PF6, BF4, ClO4, CF3SO3, and (CF3SO3)2N and a methine chain containing a 5-membered ring or a 6-membered ring in the molecule.

[0022] The cyanine dye preferably has both a counter ion as described above and cyclic structures such as a 5-membered ring and a 6-membered ring in the methine chain. However, if it has at least one of them, sufficient light resistance and heat resistance are ensured. A material having excellent light resistance and heat resistance does not decompose during laser irradiation as described above. As a means for confirming light resistance, for example, there is a method of measuring the peak change of the absorption spectrum during a xenon lamp irradiation test. If the change rate during 30 minutes of irradiation is 20% or less, it can be determined that the light resistance is good. As a means for confirming heat resistance, for example, there is a method of measuring the peak change of the absorption spectrum during storage at 150 °C. If the change rate after a 30-minute test is 20% or less, it can be determined that the heat resistance is good.

[0023] The polymer material is preferably one in which the color-forming compound, the color-developing / fading agent, and the photothermal conversion agent are easily and uniformly dispersed. Further, the polymer material preferably has high transparency in order to obtain high visibility of the information written in the recording layer 11. For example, those having high solubility in organic solvents are preferred. Examples of the polymer material include thermosetting resins and thermoplastic resins. Specifically, for example, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, ethyl cellulose, polystyrene, styrene copolymers, phenoxy resins, polyesters, aromatic polyesters, polyurethanes, polycarbonates, polyacrylic esters, polymethacrylic esters, acrylic copolymers, maleic polymers, polyvinyl alcohol, modified polyvinyl alcohol, hydroxyethyl cellulose, carboxymethyl cellulose, and starch.

[0024] The recording layer 11 is configured to contain at least one kind of each of the above color-forming compound, color-developing / fading agent, and photothermal conversion agent. The color-forming compound and the color-developing / fading agent contained in the recording layer 11 are preferably, for example, color-forming compound:color-developing / fading agent = 1:2 (weight ratio). The amount of the photothermal conversion agent varies according to the film thickness of the recording layer 11. Further, the recording layer 11 may be configured to contain various additives such as a sensitizer and an ultraviolet absorber in addition to the above materials.

[0025] The adhesive layers 12 and 13 are for bonding the recording layer 11 and, for example, the first barrier films 14 and 15 that cover the front surface (surface S1) and the back surface (surface S2) of the recording layer 11. The adhesive layer 12 is provided on the back surface (surface S2) side of the recording layer 11, and the adhesive layer 13 is provided on the front surface (surface S1) side of the recording layer 11, respectively. Similar to the polymer material constituting the recording layer 11, the adhesive layers 12 and 13 preferably have high transparency in order to obtain high visibility of the information written on the recording layer 11. For example, those having high solubility in organic solvents are preferred. Examples of the materials for the adhesive layers 12 and 13 include adhesives such as acrylic, urethane, epoxy, and silicone. The adhesive layers 12 and 13 may be provided on both sides of a base material such as PET as a support or may be only an adhesive without a base material. Alternatively, the adhesive layers 12 and 13 may be formed by laminating sheet-like materials, or may be formed by applying a solution dissolved in an organic solvent and then drying it to form an adhesive layer.

[0026] The first barrier films 14 and 15 are for suppressing the entry of moisture, oxygen, or both into the recording layer 11. The first barrier films 14 and 15 have the same planar shape as the recording layer 11. The first barrier film 14 covers the back surface (surface S2) of the recording layer 11, and the first barrier film 15 covers the front surface (surface S1).

[0027] The first barrier films 14 and 15 preferably have a water vapor transmission rate of 0.001 g / m 2 / day or more and 10 g / m 2 / day or less. Also, similar to the polymer material constituting the recording layer 11 and the adhesive layers 12 and 13, the first barrier films 14 and 15 preferably have high transparency in order to obtain high visibility of the information written on the recording layer 11. Examples of such first barrier films 14 and 15 include laminated films in which an inorganic oxide film is provided on a base material made of a plastic film. The first barrier films 14 and 15 constituted by the laminated film of the plastic film and the inorganic oxide film cover the recording layer 11 such that, for example, the inorganic oxide film is on the side of the recording layer 11 (inside) and the plastic film is on the outside.

[0028] As the base plastic film, for example, an industrial plastic film can be used, and it can be formed using at least one of polyethylene terephthalate (PET), polycarbonate (PC), and polymethyl methacrylate (PMMA). The thickness of the plastic film is preferably, for example, 5 μm or more and 100 μm or less.

[0029] As the inorganic oxide film, for example, a silicon oxide film (SiO x film), an aluminum oxide film (AlO x film), and a silicon nitride film (SiN x film), a single-layer film or a laminated film using at least one of them can be mentioned. The thickness of the first barrier films 14, 15 is preferably, for example, 10 nm or more and 1 μm or less.

[0030] The second barrier film 16 is for preventing environmental contaminants from entering the recording layer 11 and seals the ends of the recording layer 11, the adhesive layers 12, 13, and the first barrier films 14, 15. Specifically, the second barrier film 16 is, for example, provided continuously from the peripheral edge of the upper surface (surface 15S) of the first barrier film 15 provided on the surface (surface S1) side of the recording layer 11 to the peripheral edge of the lower surface (surface 14S) of the first barrier film 14 provided on the back surface (surface S2) side of the recording layer 11 with respect to the four side surfaces (surface S3) of the recording layer 11 having a rectangular shape. Note that examples of environmental contaminants include human sweat, hand cream, sunscreen cream, etc.

[0031] The second barrier film 16 preferably has high transparency in order to obtain high visibility of the information written on the recording layer 11, similar to the polymer material constituting the recording layer 11, the adhesive layers 12 and 13, and the first barrier films 14 and 15. Further, the second barrier film 16 preferably has heat resistance, and more preferably has chemical resistance. Also, the second barrier film 16 preferably has durability with a hardness of 6H or more, for example. This hardness of 6H is the pencil hardness in the JIS standard (hardness test (pencil method) according to JIS K5600-5-4), and is obtained from a scratch test in which a pencil of known hardness is pressed against the coating film to measure the hardness.

[0032] Such a second barrier film 16 can be formed using, for example, an ultraviolet curable resin or a thermosetting resin. As the ultraviolet curable resin, for example, an organic-inorganic hybrid material can be cited as an example. Specifically, for example, it is preferable to use an organic-inorganic hybrid material having a silsesquioxane skeleton represented by the composition formula [(RSiO 1.5 ) n . This makes it possible to prevent the intrusion of environmental contaminants into the recording layer 11 without degrading the appearance of the recording medium 1. The silsesquioxane skeleton is represented by, for example, the following formulas (1) to (5). In formulas (1) to (5), R is an organic group, and examples thereof include a radical polymerizable acryloyl group, a radical polymerizable methacryloyl group, and a cationic polymerizable oxetanyl group.

[0033]

Chemical formula

[0034]

Chemical formula

[0035] As described above, the second barrier film 16 is continuously provided from the peripheral edge of the upper surface (surface 15S) of the first barrier film 15 provided on the surface (surface S1) side of the recording layer 11 to the peripheral edge of the lower surface (surface 14S) of the first barrier film 14 provided on the back surface (surface S2) side of the recording layer 11. The cross-section of the second barrier film 16 in the Y-axis direction on the side surface (surface S3) has a curved surface shape as shown in FIG. 1, for example. The thickness of the second barrier film 16 is preferably, for example, 16 μm or more and 33 μm or less. Further, when the cross-section of the second barrier film 16 in the Y-axis direction has a curved surface shape as shown in FIG. 1, its maximum thickness (t1) is preferably 33 μm or less.

[0036] Furthermore, the end of the second barrier film 16 extends to a part (peripheral edge) of the upper surface (surface 15S) of the first barrier film 15 and a part (peripheral edge) of the lower surface (surface 14S) of the first barrier film 14. The width (w) of the extending portion of the second barrier film 16 on the upper surface (surface 15S) of the first barrier film 15 and the lower surface (surface 14S) of the first barrier film 14 is preferably less than 50 μm, which is the limit of human visual recognition, for example, starting from the ends of the first barrier films 14 and 15, and more preferably 33 μm or less. Also, the thickness (t2) of the second barrier film 16 extending to the second barrier film 16 on the upper surface (surface 15S) of the first barrier film 15 and the lower surface (surface 14S) of the first barrier film 14 is preferably 10 μm or less, for example.

[0037] The recording medium 1 can be used as a printing portion of an IC card, an electronic device such as a wearable terminal, a wearable display, a portable device, or a decorative member (exterior member) such as a building, although details will be described later. In this case, the recording medium 1 can be bonded, for example, as shown in FIG. 3, onto a support substrate 21 via an adhesive layer 22. The support substrate 21 is, for example, a housing of an electronic device. As the adhesive layer 22, for example, the materials mentioned for the adhesive layers 12 and 13 can be used. Also, if the support substrate 21 has high visibility such as glass or a highly transparent resin plate, it may have a structure that forms the outermost surface of various application devices.

[0038] (1-2. Manufacturing Method of Recording Medium) The recording medium 1 of this embodiment can be manufactured, for example, using a coating method. FIG. 2 is a flowchart showing an example of the manufacturing method of the recording medium 1. Note that the manufacturing method described below is an example, and it may be manufactured using other methods.

[0039] First, for example, polyvinyl acetate is dissolved as a polymer material in a solvent (for example, methyl ethyl ketone). A developer / fading agent, a color-forming compound, and a photothermal conversion agent are added to and dispersed in this solution. Thereby, a paint for a recording medium is obtained. Subsequently, this paint for a recording medium is applied onto a support substrate 21 at a thickness of, for example, 3 μm and dried at, for example, 70° C. to form a recording layer 11. Next, a thermosetting acrylic resin dissolved in an organic solvent, for example, is applied onto the front surface (surface S1) and the back surface (surface S2) of the recording layer 11 at a thickness of, for example, 10 μm and then dried to form adhesive layers 12 and 13 (step S101).

[0040] Subsequently, a first barrier film 14 having a SiO2 film formed thereon using, for example, a CVD method on a plastic film is bonded to the back surface (surface S2) of the recording layer 11 via the adhesive layer 12. Similarly, a first barrier film 15 having a SiO2 film formed thereon using, for example, a CVD method on a plastic film is bonded to the front surface (surface S1) of the recording layer 11 via the adhesive layer 13 (step S102).

[0041] Next, a second barrier film 16 is formed on the side surface (surface S3) of the recording layer 11 including the adhesive layers 12, 13 and the first barrier films 14, 15, for example, using the following method (steps S103, S104). First, a liquid ultraviolet curable resin is applied to a glass substrate with good flatness to a predetermined film thickness using a bar coater. Subsequently, the ultraviolet curable resin applied on the glass substrate is transferred by pressing the side surface (surface S3) of the recording layer 11 including the adhesive layers 12, 13 and the first barrier films 14, 15 against it (step S103). Then, for example, using an ultraviolet curing device equipped with a high-pressure mercury lamp, while purging with nitrogen (N2) gas, ultraviolet rays (UV light) are irradiated onto each side surface (surface S3) for a predetermined time to cure the ultraviolet curable resin (step S104). Thereby, the recording medium 1 shown in FIG. 1 is completed.

[0042] (1-3. Method for Recording and Erasing on Recording Medium) In the recording medium 1 of the present embodiment, for example, recording and erasing can be performed as follows.

[0043] First, the recording layer 11 is heated to a temperature at which the color-developing compound fades, for example, 120°C, and is preliminarily set in a faded state. Next, near-infrared rays with adjusted wavelength and output are irradiated onto a desired position of the recording layer 11, for example, by a semiconductor laser or the like. Thereby, the photothermal conversion agent contained in the recording layer 11 generates heat, and a color-forming reaction (color-developing reaction) occurs between the color-developing compound and the color-developing / diminishing agent, and the irradiated portion develops color.

[0044] On the other hand, when fading the colored portion, it is irradiated with near-infrared rays with energy sufficient to reach the fading temperature. Thereby, the photothermal conversion agent contained in the recording layer 11 generates heat, and a fading reaction occurs between the color-developing compound and the color-developing / diminishing agent, the color of the irradiated portion disappears, and the recording is erased. Also, when erasing all the recordings formed on the recording layer 11 at once, the recording medium 1 is heated to a temperature sufficient to fade it, for example, 120°C. Thereby, the information recorded on the recording layer 11 is erased at once. After that, by performing the above-described operations, repeated recording on the recording layer 11 becomes possible.

[0045] Unless the color development reaction and the color fading reaction such as the irradiation and heating of the near-infrared rays described above are performed, the colored state and the colorless state are maintained.

[0046] (1-4. Action and Effect) In the recording medium 1 of the present embodiment, first barrier films 14 and 15 that suppress the incorporation of at least one of moisture and oxygen are provided on the front surface (surface S1) and the back surface (surface S2) of the recording layer 11 via adhesive layers 12 and 13, respectively. Further, a second barrier film 16 having chemical resistance is provided from the peripheral edge of the upper surface (surface 15S) of the first barrier film 15 provided on the front surface (surface S1) side of the recording layer 11 to the peripheral edge of the lower surface (surface 14S) of the first barrier film 14 provided on the back surface (surface S2) side of the recording layer 11 so as to be continuously provided on the side surface (surface S3) of the recording layer 11 including the adhesive layers 12 and 13 and the first barrier films 14 and 15. As a result, it is possible to reduce the non-display area at the outer edge of the recording layer 11 while suppressing the intrusion of environmental contaminants into the recording layer 11. This will be described below.

[0047] In recent years, the development of display media to replace printed matter has been underway, and as one of them, a recording medium capable of reversibly recording and erasing information by heat has attracted attention. Such a recording medium generally includes a color-forming compound having electron-donating properties, a color-developing / fading agent having electron-accepting properties, and a matrix polymer. Further, by adding a photothermal conversion agent to the recording medium, recording and erasing can be performed by irradiating light of a specific wavelength. The recording medium is assumed to be used for, for example, printing on IC cards and labels, as well as for decorating the surface of the housing of electronic devices and for the interior and exterior decoration of buildings.

[0048] In the recording medium, for example, a leuco dye is used as a color former. However, in such a recording medium, there is a problem that the optical color density in the vicinity of the end face decreases due to the intrusion of moisture and oxygen from the end face, resulting in a decrease in display quality. As a method for solving this problem, for example, a method of putting the recording medium in a packaging bag made of a gas barrier laminate and adhering the outer peripheral portion by heat welding can be considered. Further, a method of sandwiching the recording medium with a barrier layer and sealing the end face with a two-component curable adhesive can be considered. Alternatively, a method of sealing the moisture-proof film at the recovery end of the recording medium with a resin film and a laminating agent can be considered. However, when the above method is used, there is a possibility that a sealing width will be formed on the end face of the recording medium, resulting in a decrease in designability.

[0049] Further, in the recording medium as described above, for example, there is a possibility that the display quality deteriorates due to discoloration or the like caused by the adhesion of environmental contaminants such as human sweat, hand cream, and sunscreen cream. This is presumably due to cracks on the surface generated around the processed portion when the recording medium is processed into a predetermined size and shape in the manufacturing process of the recording medium, and the intrusion of chemicals from the processed end portion.

[0050] On the other hand, in the present embodiment, first barrier films 14 and 15 for suppressing the intrusion of at least one of moisture and oxygen are provided on the front surface (surface S1) and the back surface (surface S2) of the recording layer 11 via adhesive layers 12 and 13, respectively. Further, a second barrier film 16 having chemical resistance is continuously provided on the side surface (surface S3) of the recording layer 11 including the adhesive layers 12 and 13 and the first barrier films 14 and 15. Further, the second barrier film 16 extends to a part of the upper surface (surface 15S) of the first barrier film 15 and a part of the lower surface (surface 14S) of the first barrier film 14 so as to cover the respective peripheral portions. As a result, it is possible to reduce the sealing width of the outer edge portion that becomes the non-display area of the recording medium 1 and prevent the intrusion of environmental contaminants from cracks generated on the side surface (surface S3) and the peripheral surface of the first barrier films 14 and 15.

[0051] As described above, in the recording medium 1 of the present embodiment, the front surface (surface S1) and the back surface (surface S2) of the recording layer 11 are covered with the first barrier films 14 and 15, and the side surfaces (surface S3) of the recording layer 11 including the adhesive layers 12 and 13 and the first barrier films 14 and 15 and the peripheral portions of the first barrier films 14 and 15 are covered with the second barrier film 16 having chemical resistance. Therefore, the intrusion of environmental contaminants from cracks generated on the side surface (surface S3) and the peripheral surface of the first barrier films 14 and 15 is reduced. As a result, it is possible to improve the durability of the display quality and the designability. Therefore, it is possible to provide an electronic device or a decorative member having excellent design.

[0052] Next, modified examples (modified examples 1 to 5) of the present disclosure will be described. Hereinafter, the same components as those in the above embodiment will be denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0053] <2. Modified Example> (2-1. Modified Example 1) FIG. 4 schematically shows an example of a cross-sectional configuration of a recording medium (recording medium 2) according to Modified Example 1 of the present disclosure. In the above embodiment, an example in which the recording layer 11 including the adhesive layers 12 and 13 and the first barrier films 14 and 15 has a side surface (surface S3) substantially perpendicular to the plane direction (XZ direction) of the recording layer 11 is shown. However, the side surface (surface S3) may be, for example, an inclined surface with an obtuse angle on the surface (surface S1) side of the recording layer 11 as shown in FIG. 4. The inclined side surface (surface S3) is formed, for example, by processing the recording medium 2 using a laser.

[0054] In the recording medium 2 of this modification example, the curved surface shape of the second barrier film 16 on the side surface (surface S3) has different curvatures on the front surface (surface S1) side and the back surface (surface S2) side of the recording layer 11. Specifically, for example, as shown in FIG. 4, the cross section of the recording layer 11 including the adhesive layers 12 and 13 and the first barrier films 14 and 15 has a trapezoidal shape, and when the length of the lower base (back surface (surface S2) side) is larger than the length of the upper base (front surface (surface S1) side), the curvature on the back surface (surface S2) side has a larger curvature than that on the front surface (surface S1) side. Also, in this embodiment, the second barrier film 16 on the side surface (surface S3) has the maximum thickness on the back surface (surface S2) side of the recording layer 11.

[0055] Thus, even in the recording medium 2 in which the side surface (surface S3) of the recording layer 11 including the adhesive layers 12 and 13 and the first barrier films 14 and 15 is an inclined surface, the same effects as those in the above embodiment can be obtained. Also, as in this modification example, by making the side surface (surface S3) an inclined surface and attaching the first barrier film 14 side to the support substrate 21 or the like, there is an effect that peeling or damage of the recording medium 2 due to catching at the end can be suppressed. Also, there is an effect that it is easy to control the film thickness of the second barrier film 16.

[0056] Note that in FIG. 4, an example in which the length of the back surface (surface S2) side of the recording layer 11 is larger than the length of the front surface (surface S1) side is shown, but the shape may be such that the length of the front surface (surface S1) side of the recording layer 11 is larger than the length of the back surface (surface S2) side.

[0057] (2-2. Modification Example 2) FIG. 5 schematically shows an example of the cross-sectional shape of a recording medium (recording medium 3) according to Modification Example 2 of the present disclosure. A hard coat layer 17 may be further provided on the first barrier film 15 on the front surface (surface S1) side of the recording layer 11.

[0058] When the recording medium is disposed on the outermost surface, the hard coat layer 17 serves to protect against cutting, scratching, indentation, solvents, etc. on the surface. The hard coat layer 17 is formed by including, for example, an ultraviolet curable acrylic resin, a melamine resin, or a urethane resin. The thickness of the hard coat layer 17 is preferably, for example, 1 μm or more and 20 μm or less.

[0059] Furthermore, another optical thin film may be provided between the first barrier film 15 and the hard coat layer 17. Examples of the other optical thin film include a UV absorption layer. The UV absorption layer is formed by including, for example, an ultraviolet absorber, and is for absorbing ultraviolet rays (for example, having a wavelength of 200 nm or more and 500 nm or less) contained in external light or the like to reduce the exposure of the recording layer 11 to ultraviolet rays. The ultraviolet absorber has absorption in a wavelength range of 500 nm or less, and examples thereof include triazine, benzotriazole, benzophenone, and the like.

[0060] Thus, by providing the hard coat layer 17 on the surface (surface S1) side of the recording layer 11, in addition to the effects of the above-described embodiment, it becomes possible to prevent deterioration of the recording layer 11 due to ultraviolet rays, solvents, or physical impact, and it becomes possible to further improve the durability of the display quality.

[0061] (2-3. Modification 3) FIG. 6 schematically shows an example of a cross-sectional configuration of a recording medium (recording medium 4) according to Modification 3 of the present disclosure. In the above-described embodiment, an example in which the second barrier film 16 is continuously provided from the peripheral edge portion of the upper surface (surface 15S) of the first barrier film 15 to the peripheral edge portion of the lower surface (surface 14S) of the first barrier film 14 on the side surface (surface S3) of the recording layer 11 including the adhesive layers 12 and 13 and the first barrier films 14 and 15 is shown, but the second barrier film 16 may cover the entire surfaces of the first barrier films 14 and 15.

[0062] The second barrier film 16 that covers the first barrier film 14 can also serve as, for example, the above-described hard coat layer 17.

[0063] Thus, in addition to the side surface (surface S3) of the recording layer 11 including the adhesive layers 12 and 13 and the first barrier films 14 and 15, by providing the second barrier film 16 on the entire surfaces of the first barrier films 14 and 15, in addition to the effects of the above-described embodiment, an effect is achieved in that information can be uniformly recorded or erased up to the end portions of the recording layer 11. Further, since the interface between the first barrier film 15 and the second barrier film 16 on the surface of the recording medium 4 disappears, the visibility can be improved. Further, it becomes possible to further reduce the permeation (infiltration) of moisture into the recording layer 11.

[0064] (2-4. Modified Example 4) FIG. 7 schematically shows a cross-sectional configuration of a recording medium (recording medium 5) according to Modified Example 4 of the present disclosure. In the above-described embodiment and the like, an example having a single-layer recording layer 11 was shown, but a recording layer (recording layer 31) may be provided with a plurality of layers. The recording medium 5 of this modified example is different from the above-described embodiment in that it has a recording layer 31 having a laminated structure in which, for example, three layers (first layer 31A, second layer 31B, and third layer 31C) are laminated. Intermediate layers 32 and 33 are provided as heat insulating layers between the respective layers 31A, 31B, and 31C constituting the recording layer 31.

[0065] The recording layer 31 is, for example, capable of reversibly recording and erasing information by heat, and has a configuration in which, for example, the first layer 31A, the second layer 31B, and the third layer 31C are laminated in this order. The first layer 31A, the second layer 31B, and the third layer 31C are formed by dispersing a color-developing compound exhibiting different colors, a color-developing / diminishing agent corresponding to each color-developing compound, and a photothermal conversion agent that absorbs light in different wavelength ranges and generates heat, for example, in a polymer material.

[0066] Specifically, the first layer 31A is composed of, for example, a color-developing compound that develops cyan color (for example, color-developing compound A), a corresponding developing / fading agent (for example, developing / fading agent A), and a photothermal conversion agent that absorbs infrared rays with a wavelength of λ1 and exhibits photothermal conversion (for example, photothermal conversion agent A). The second layer 31B is composed of, for example, a color-developing compound that exhibits magenta color (for example, color-developing compound B), a corresponding developing / fading agent (for example, developing / fading agent B), and a photothermal conversion agent that absorbs infrared rays with a wavelength of λ2 and generates heat (for example, photothermal conversion agent B). The third layer 31C is composed of, for example, a color-developing compound that exhibits yellow color (for example, color-developing compound C), a corresponding developing / fading agent (for example, developing / fading agent C), and a photothermal conversion agent that absorbs infrared rays with a wavelength of λ3 and generates heat (for example, photothermal conversion agent C). The wavelengths λ1, λ2, and λ3 are different from each other, whereby a display medium capable of multi-color display can be obtained.

[0067] In addition, for the photothermal conversion agent, it is preferable to select a combination of materials having a narrow light absorption band and not overlapping with each other, for example, in the range of 700 nm or more and 2000 nm or less in wavelength. Thereby, it becomes possible to selectively develop or fade a desired layer among the first layer 31A, the second layer 31B, and the third layer 31C.

[0068] The thicknesses of the first layer 31A, the second layer 31B, and the third layer 31C are preferably, for example, 1 μm or more and 20 μm or less respectively, and more preferably, for example, 2 μm or more and 15 μm or less. This is because if the thickness of each of the layers 31A, 31B, and 31C is less than 1 μm, there is a possibility that sufficient color development density cannot be obtained. Also, when the thickness of each of the layers 31A, 31B, and 31C is greater than 20 μm, the heat utilization amount of each of the layers 31A, 31B, and 31C increases, and there is a possibility that the color development property and the color fading property deteriorate.

[0069] In addition, similar to the above-described recording layer 11, the first layer 31A, the second layer 31B, and the third layer 31C may be composed of, in addition to the above materials, various additives such as a sensitizer and an ultraviolet absorber.

[0070] Furthermore, in the recording layer 31 of this modified example, intermediate layers 32 and 33 are provided between the first layer 31A and the second layer 31B, and between the second layer 31B and the third layer 31C, respectively. The intermediate layers 32 and 33 are formed using, for example, a general-purpose polymer material having light transmissivity. Specific materials include, for example, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, ethyl cellulose, polystyrene, styrene copolymer, phenoxy resin, polyester, aromatic polyester, polyurethane, polycarbonate, polyacrylate, polymethacrylate, acrylic copolymer, maleic polymer, polyvinyl alcohol, modified polyvinyl alcohol, hydroxyethyl cellulose, carboxymethyl cellulose, and starch. Note that the intermediate layers 32 and 33 may be formed to contain various additives such as an ultraviolet absorber.

[0071] Also, the intermediate layers 32 and 33 may be formed using an inorganic material having light transmissivity. For example, by using porous silica, alumina, titania, carbon, or a composite thereof, etc., the thermal conductivity is lowered and the heat insulation effect is high, which is preferable. The intermediate layers 32 and 33 can be formed, for example, by the sol-gel method.

[0072] The thickness of the intermediate layers 32 and 33 is preferably, for example, 3 or more and 100 μm or less, and more preferably, for example, 5 μm or more and 50 μm or less. If the thickness of the intermediate layers 32 and 33 is too thin, a sufficient heat insulation effect cannot be obtained, and if it is too thick, the thermal conductivity deteriorates or the light transmissivity decreases when the entire recording medium 2 is uniformly heated.

[0073] Furthermore, the side surface (surface S3) of the recording layer 31 including the adhesive layers 12 and 13 and the first barrier films 14 and 15 may be an inclined surface, for example, in the same manner as the recording medium 2 in Modified Example 1. Also, a hard coat layer 17 or the like may be provided on the first barrier film 15 in the same manner as the recording medium 3 in Modified Example 3. Furthermore, in the same manner as the recording medium 4 in Modified Example 4, the entire surface of the first barrier films 14 and 15 may be covered with the second barrier film 16.

[0074] In the recording medium 5 of this modification example, for example, recording and erasing can be performed as follows. Here, the case where the recording layer 31 is laminated with the first layer 31A, the second layer 31B, and the third layer 31C that exhibit cyan, magenta, and yellow, respectively, as described above will be described as an example.

[0075] First, heat the recording layer 31 (the first layer 31A, the second layer 31B, and the third layer 31C) to a temperature at which it fades, for example, 120°C, and make it fade in advance. Next, irradiate an arbitrary portion of the recording layer 31 with infrared rays having arbitrarily selected wavelengths and outputs, for example, by a semiconductor laser or the like. Here, when causing the first layer 31A to develop color, irradiate the first layer 31A with infrared rays having a wavelength λ1 with energy such that the first layer 31A reaches the color-developing temperature. As a result, the photothermal conversion agent A contained in the first layer 31A generates heat, and a color-developing reaction (coloring reaction) occurs between the color-forming compound A and the color-developing / dyeing agent A, and cyan develops in the irradiated portion. Similarly, when causing the second layer 31B to develop color, irradiate the second layer 31B with infrared rays having a wavelength λ2 with energy such that the second layer 31B reaches the color-developing temperature. When causing the third layer 31C to develop color, irradiate the third layer 31C with infrared rays having a wavelength λ3 with energy such that the third layer 31C reaches the color-developing temperature. As a result, the photothermal conversion agents B and C contained in the second layer 31B and the third layer 31C generate heat, respectively, and a color-developing reaction occurs between the color-forming compound and the color-developing / dyeing agent, and magenta and yellow develop in the irradiated portions, respectively. In this way, by irradiating an arbitrary portion with infrared rays of the corresponding wavelength, recording of information (for example, a full-color image) becomes possible.

[0076] On the one hand, when erasing the first layer 31A, the second layer 31B, and the third layer 31C that have been colored as described above, each layer 31A, 31B, 31C is irradiated with infrared light of a wavelength corresponding to each layer at an energy level sufficient to reach the erasing temperature. As a result, the photothermal conversion agents A, B, and C contained in the first layer 31A, the second layer 31B, and the third layer 31C generate heat respectively, and a decolorization reaction occurs between the color-forming compound A and the color-developing / decolorizing agent A, between the color-forming compound B and the color-developing / decolorizing agent B, and between the color-forming compound C and the color-developing / decolorizing agent C. The color of the irradiated portion disappears and the recording is erased. Also, when erasing all the recordings formed on the recording layer 31 at once, by heating the recording layer 31 to a temperature at which all of the first layer 31A, the second layer 31B, and the third layer 31C are decolorized, for example, 120 °C, the information recorded on the recording layer 31 (the first layer 31A, the second layer 31B, and the third layer 31C) is erased all at once. After that, by performing the above-described operations, repeated recording on the recording layer 31 becomes possible.

[0077] As described above, in this modified example, for example, three kinds of layers (the first layer 31A, the second layer 31B, and the third layer 31C) containing a color-forming compound (color-forming compound A, color-forming compound B, color-forming compound C) that exhibits yellow, magenta, or cyan respectively, a corresponding color-developing / decolorizing agent (color-developing / decolorizing agent A, color-developing / decolorizing agent B, color-developing / decolorizing agent C), and a photothermal conversion agent (photothermal conversion agent A, photothermal conversion agent B, photothermal conversion agent C) having mutually different absorption wavelengths are formed and laminated. Thereby, it becomes possible to provide the recording medium 5 capable of multi-color recording.

[0078] (2-5. Modified Example 5) In the above-described modified example 4, the recording medium 5 having a multilayer structure in which a plurality of layers (the first layer 31A, the second layer 31B, and the third layer 31C) exhibiting mutually different colors are formed as the recording layer 31 and laminated was shown. However, for example, a recording medium (recording medium 6) capable of multi-color display can be realized even with a single-layer structure.

[0079] FIG. 8 shows a recording layer 41 formed by mixing three types of microcapsules 41a, 41b, and 41c, each containing a color-forming compound (color-forming compound A, color-forming compound B, color-forming compound C) that exhibits different colors (e.g., cyan (C), magenta (M), and yellow (Y)), a color-developing / decolorizing agent (color-developing / decolorizing agent A, color-developing / decolorizing agent B, color-developing / decolorizing agent C) corresponding to each color-forming compound, and a photothermal conversion agent (photothermal conversion agent A, photothermal conversion agent B, photothermal conversion agent C) that absorbs light in different wavelength ranges and generates heat. This recording layer 41 can be formed, for example, by dispersing the microcapsules 41a, 41b, and 41c in a polymer material, such as the constituent material of the recording layer 11 described above, and coating it on the support substrate 21. Note that it is preferable to use, for example, the material that constitutes the intermediate layers 32 and 33 for the microcapsules 41a, 41b, and 41c that encapsulate the above materials.

[0080] As described above, in this modification, for example, a color-forming compound (color-forming compound A, color-forming compound B, color-forming compound C) that exhibits yellow, magenta, or cyan, a corresponding color-developing / decolorizing agent (color-developing / decolorizing agent A, color-developing / decolorizing agent B, color-developing / decolorizing agent C), and a photothermal conversion agent (photothermal conversion agent A, photothermal conversion agent B, photothermal conversion agent C) having different absorption wavelengths are respectively encapsulated in the microcapsules 41a, 41b, and 41c, and these are dispersed in a polymer material to form the recording layer 41. As a result, it becomes possible to provide the recording medium 3 capable of multi-color recording having a single-layer structure.

[0081] In the above-described embodiments and Modification 4, etc., examples of forming the recording layer 11 and the recording layer 31 (the first layer 31A, the second layer 31B, and the third layer 31C) using a single (one type) color-forming compound are shown, but the present invention is not limited thereto. The recording layers 11 and 31 (the first layer 31A, the second layer 31B, and the third layer 31C) may be formed by mixing and using a plurality of types of color-forming compounds that exhibit different colors.

[0082] In a recording medium, it is difficult to perform color reproduction of Japan color's CMY (cyan, magenta, yellow) using a single color-forming compound (leuco dye). Further, since the photothermal conversion agent has a slight tint, the tint of the recording layers 11 and 31 changes slightly depending on the type and content of the photothermal conversion agent. Developing a color-forming compound each time for this slight change significantly reduces the production efficiency.

[0083] Therefore, by forming the recording layer 11 and the recording layer 31 (the first layer 31A, the second layer 31B, and the third layer 31C) by mixing a plurality of types of color-forming compounds (color-forming compound A, color-forming compound B, color-forming compound C), it becomes possible to reproduce various colors including Japan color's CMY. For example, cyan can be reproduced by mixing a color-forming compound that exhibits blue and a color-forming compound that exhibits green at a predetermined ratio. Magenta can be reproduced by mixing a color-forming compound that exhibits red and a color-forming compound that exhibits orange at a predetermined ratio.

[0084] <3. Application Examples> Next, application examples of the recording media (recording media 1 to 6) described in the above embodiments and modification examples 1 to 5 will be described. The above recording media 1 to 6 are applicable to various electronic devices or parts of clothing. Examples of various electronic devices include so-called wearable terminals such as watches (wristwatches) and headphones. In addition, examples of various electronic devices include wearable displays such as head-up displays and head-mounted displays, portable devices such as portable music players and portable game machines, robots, or refrigerators and washing machines. The type of electronic device is not particularly limited. Examples of clothing include bags, clothes, hats, helmets, glasses, and shoes. Further, not limited to electronic devices and clothing, for example, as a decorative member, it can also be applied to the interior and exterior of automobiles, the interior and exterior of walls of buildings, the exterior of furniture such as desks, the interior and exterior of walls of buildings, the exterior of furniture such as desks, etc. Note that the configurations of the electronic devices and the like described below are merely examples, and the configurations can be changed as appropriate.

[0085] (Application Example 1) Figures 9A and 9B show the appearance of an IC card with a rewrite function. In this IC card, the surface of the card is the printing surface 110, and for example, a sheet-like recording medium 1 or the like is attached to form it. By arranging the recording medium 1 or the like on the printing surface 110, as shown in Figures 9A and 9B, drawing, rewriting, and erasing can be appropriately performed on the printing surface. Here, an IC card is taken as an example, but it is not limited to this. For example, it can also be applied to identity cards and the like.

[0086] (Application Example 2) Figure 10A shows the external appearance configuration of the front of a smartphone, and Figure 10B shows the external appearance configuration of the back of the smartphone shown in Figure 10A. This smartphone includes, for example, a display unit 210, a non-display unit 220, and a housing 230. For example, on one surface of the housing 230 on the back side, a recording medium 1 is provided as an exterior member of the housing 230. As a result, as shown in Figure 10B, various color patterns can be displayed on the housing 230. Here, a smartphone is taken as an example, but it is not limited to this. For example, it can also be applied to notebook personal computers (PCs), tablet PCs, and the like.

[0087] (Application Example 3) Figures 11A and 11B show the appearance of a bag. This bag has, for example, a storage portion 310 and a handle 320. For example, a recording medium 1 is attached to the storage portion 310. Various characters and patterns are displayed on the storage portion 310 by the recording medium 1. Also, by attaching the recording medium 1 or the like to the handle 320 portion, various color patterns can be displayed, and the design of the storage portion 310 can be changed from the example in Figure 11A to the example in Figure 11B. It is possible to realize an electronic device that is also useful in the fashion field.

[0088] (Application Example 4) FIG. 12 shows a configuration example of a list band that can record, for example, the ride history and schedule information of attractions in an amusement park. This list band has belt portions 411 and 412, and an information recording portion 420. The belt portions 411 and 412 have, for example, a belt shape, and their ends (not shown) are configured to be connectable to each other. For example, a recording medium 1 is attached to the information recording portion 420, and in addition to the ride history MH2 and schedule information IS (IS1 to IS3) of the attractions, for example, an information code CD is recorded. In the amusement park, an admission person can record the above information by holding the list band in front of a drawing device installed at various places such as a ride reservation spot for an attraction.

[0089] The ride history mark MH1 indicates the number of attractions that an admission person wearing the list band has ridden in the amusement park. In this example, as the admission person rides an attraction, more star marks are recorded as the ride history mark MH1. Note that the present invention is not limited to this, and for example, the color of the mark may change according to the number of attractions that the admission person has ridden.

[0090] The schedule information IS indicates the schedule of the admission person in this example. In this example, information on all events including the events reserved by the admission person and the events held in the amusement park is recorded as schedule information IS1 to IS3. Specifically, in this example, the name of the attraction (Attraction 201) for which the admission person has made a ride reservation and the scheduled ride time are recorded as schedule information IS1. Also, the event in the park such as a parade and its scheduled start time are recorded as schedule information IS2. Further, the restaurant reserved in advance by the admission person and the scheduled meal time are recorded as schedule information IS3.

[0091] The information code CD records, for example, identification information IID for identifying the list band and website information IWS.

[0092] (Application Example 5) FIG. 13A shows the appearance of the upper surface of an automobile, and FIG. 13B shows the appearance of the side surface of the automobile. As described above, the recording medium 1 etc. of the present disclosure can display various information and patterns on each part by being provided on the vehicle body such as, for example, the bonnet 611, the bumper 612, the roof 613, the trunk cover 614, the front door 615, the rear door 616, and the rear bumper 617. Further, the recording medium 1 etc. can display various patterns by being provided on the interior of the automobile, for example, on the steering wheel, dashboard, etc.

[0093] (Application Example 6) FIG. 14 shows the appearance of a cosmetic container. This cosmetic container has, for example, a housing portion 710 and a lid 720 that covers the housing portion 710. For example, the recording medium 1 is attached to at least one of the front and back surfaces of the lid 720. The lid 720 is decorated with, for example, a pattern, a color pattern, or characters as shown in FIG. 14 by this recording medium 1. The pattern, color pattern, or characters etc. of this lid 720 can be rewritten and erased by, for example, a drawing and erasing device installed in a sales store.

[0094] <4. Examples> Next, the examples of the present disclosure will be described in detail.

[0095] (Experimental Example 1) First, a recording layer (corresponding to the recording layer 11) is formed using the manufacturing method described above, and 0.01 g / m is applied to its front and back surfaces 2A barrier film (corresponding to the first barrier films 14 and 15) composed of a laminated film of a plastic film and an inorganic oxide film having a water vapor transmission rate of / day was bonded via an adhesive layer (corresponding to the adhesive layers 12 and 13), respectively. Subsequently, an organic-inorganic hybrid resin (SILPULUS manufactured by Nippon Steel Chemical & Material Co., Ltd.) was applied onto a glass substrate with a film thickness of 8 μm using a bar coater (SELECTROLLER manufactured by OSP Co., Ltd.). By pressing the side surface of the recording layer including the barrier film and the adhesive layer against the organic-inorganic hybrid resin on this glass substrate, the organic-inorganic hybrid resin was transferred to form a barrier film (corresponding to the second barrier film 16). Thereafter, using an ultraviolet curing device equipped with a high-pressure mercury lamp (HB400E-1 manufactured by Sen Special Light Source Co., Ltd., wavelength: 365 nm, illuminance: 10 mW / cm 2 ), while purging with nitrogen (N2) gas, each side was irradiated with UV light of about 150 seconds for a total of 1500 mj / cm 2 to cure the organic-inorganic hybrid resin and produce a recording medium.

[0096] (Experimental Example 2) In Experimental Example 2, a recording medium was produced in the same manner as in Experimental Example 1 except that the organic-inorganic hybrid resin was applied onto the glass substrate with a film thickness of 16 μm.

[0097] (Experimental Example 3) In Experimental Example 3, a recording medium was produced in the same manner as in Experimental Example 1 except that the organic-inorganic hybrid resin was applied onto the glass substrate with a film thickness of 22 μm.

[0098] (Experimental Example 4) In Experimental Example 4, a recording medium was produced in the same manner as in Experimental Example 1 except that the organic-inorganic hybrid resin was applied onto the glass substrate with a film thickness of 33 μm.

[0099] (Experimental Example 5) In Experimental Example 5, a recording medium was produced in the same manner as in Experimental Example 1 except that the organic-inorganic hybrid resin was applied onto the glass substrate with a film thickness of 53 μm.

[0100] (Experimental Example 6) In Experimental Example 6, a recording medium was produced in the same manner as in Experimental Example 1, except that modified acrylate A was applied onto a glass substrate with a film thickness of 30 μm instead of the organic-inorganic hybrid resin.

[0101] (Experimental Example 7) In Experimental Example 7, a recording medium was produced in the same manner as in Experimental Example 6, except that modified acrylate A was applied onto a glass substrate with a film thickness of 60 μm.

[0102] (Experimental Example 8) In Experimental Example 8, a recording medium was produced in the same manner as in Experimental Example 6, except that modified acrylate A was applied onto a glass substrate with a film thickness of 90 μm.

[0103] (Experimental Example 9) In Experimental Example 9, a recording medium was produced in the same manner as in Experimental Example 6, except that modified acrylate A was applied onto a glass substrate with a film thickness of 120 μm.

[0104] (Experimental Example 10) In Experimental Example 10, a recording medium was produced in the same manner as in Experimental Example 1, except that modified acrylate B was applied onto a glass substrate with a film thickness of 30 μm instead of the organic-inorganic hybrid resin.

[0105] (Experimental Example 11) In Experimental Example 11, a recording medium was produced in the same manner as in Experimental Example 10, except that modified acrylate B was applied onto a glass substrate with a film thickness of 60 μm.

[0106] (Experimental Example 12) In Experimental Example 12, a recording medium was produced in the same manner as in Experimental Example 10, except that modified acrylate B was applied onto a glass substrate with a film thickness of 90 μm.

[0107] (Experimental Example 13) In Experimental Example 13, a recording medium was produced in the same manner as in Experimental Example 10, except that modified acrylate B was applied onto a glass substrate with a film thickness of 120 μm.

[0108] The chemical resistance of Experimental Examples 1 to 13 was evaluated. Also, the appearance of Experimental Examples 1 to 5 was evaluated.

[0109] (Evaluation of Chemical Resistance and Appearance) First, the recording media prepared in Experimental Examples 1 to 13 above were observed. Subsequently, sunscreen cream (Mentholatum Sunplay Super Block d, manufactured by Rohto Pharmaceutical Co., Ltd.) was applied as a chemical to the surface of the recording medium, and then it was stored in a thermostat at a temperature of 60°C and a humidity of 80% for 24 hours. After that, it was returned to room temperature and the sunscreen cream was wiped off and observed. For chemical resistance, it was evaluated based on the presence or absence of discoloration before and after holding at a constant temperature by visual inspection. For appearance, the visibility of the information written in the recording layer was evaluated by visual inspection. Table 3 summarizes the evaluation results of the chemical resistance of Experimental Examples 1 to 13 and the appearance of Experimental Examples 1 to 5. When no discoloration was confirmed and the information written in the recording layer could be clearly visually recognized, it was rated as A. When discoloration was confirmed and the information written in the recording layer could not be clearly visually recognized, it was rated as B.

[0110]

Table 1

[0111] From Table 1, in Experimental Examples 1 to 5 in which a side barrier film (second barrier film) was formed using an organic-inorganic hybrid resin, good evaluation results for chemical resistance and appearance were obtained in Experimental Examples 2 to 3 with a coating film thickness of 16 μm to 33 μm. In Experimental Example 1 with a coating film thickness of 8 μm, discoloration was confirmed in the recording layer after holding at a constant temperature. In Experimental Example 5 with a coating film thickness of 53 μm, the visibility decreased. On the other hand, in Experimental Examples 6 to 13 in which a side barrier film (second barrier film) was formed using modified acrylates A and B, discoloration of the recording layer was confirmed in all cases after holding at a constant temperature regardless of the film thickness. From the above, it was found that the side barrier film (second barrier film) is preferably formed using an organic-inorganic hybrid resin, and the preferred film thickness is 16 μm to 33 μm.

[0112] The present disclosure has been described above by way of embodiments, Modification Examples 1 to 5, Application Examples, and Examples. However, the present disclosure is not limited to the aspects described in the above embodiments and the like, and various modifications are possible. For example, in the above embodiments and the like, a recording layer having reversibility (for example, the recording layer 11) has been shown as an example, but writing to the recording layer may be irreversible.

[0113] Further, it is not necessary to include all the components described in the above embodiments and the like, and other components may be further included. For example, a reflective layer may be provided on the back surface (surface S2) of the recording layer 11. Thereby, clearer color display becomes possible. This reflective layer may be provided in contact with the surface S2 of the recording layer 11, or may be provided via an adhesive layer 12, first barrier films 14, 15, or the like. Furthermore, the materials and thicknesses of the above-described components are merely examples and are not limited to those described.

[0114] Furthermore, in Modification Example 5 above, an example of performing multicolor display in a single-layer structure using microcapsules has been shown, but the present invention is not limited to this. For example, it can also be performed by a fibrous three-dimensional structure. The fiber used here preferably has a so-called core-sheath structure composed of a core portion containing a color-developing compound exhibiting a desired color, a developer / fading agent corresponding thereto, and a photothermal conversion agent, and a sheath portion that covers the core portion and is composed of a heat insulating material. By forming a three-dimensional structure using a plurality of types of fibers having a core-sheath structure and containing color-developing compounds exhibiting different colors, a recording medium capable of multicolor display can be produced.

[0115] Also, in the above embodiments and the like, examples of causing color development and color erasure of each recording layer using a laser have been shown, but the present invention is not limited to this. For example, it may be performed using a thermal head.

[0116] Note that the effects described in this specification are merely examples and are not limiting, and there may be other effects.

[0117] Note that the present disclosure can also adopt the following configuration. According to the present technology having the following configuration, since the second barrier film having chemical resistance is continuously provided on the side surface of the recording layer from the side surface of the recording layer and the peripheral portion of one surface of the recording layer to the peripheral portion of the other surface, while suppressing the intrusion of environmental contaminants into the recording layer, the non-display area at the outer edge of the recording layer is reduced. Therefore, it becomes possible to provide a recording medium having excellent display quality durability and design. (1) A recording layer containing a leuco dye as a color-forming compound, A first barrier film provided on one surface of the recording layer and the other surface facing the one surface, suppressing the incorporation of at least one of moisture and oxygen, A second barrier film having chemical resistance and continuously provided on the side surface of the recording layer from at least the peripheral portion of the one surface of the recording layer to the peripheral portion of the other surface comprises The second barrier film contains an ultraviolet curable resin The ultraviolet curable resin is an organic-inorganic hybrid material The organic-inorganic hybrid material has a silsesquioxane skeleton represented by the compositional formula [(RSiO 1.5 ) n . Recording medium. (2) The recording medium according to (1) above, wherein the film thickness of the second barrier film covering the side surface of the recording layer is 16 μm or more and 33 μm or less. (3) The recording medium according to (1) or (2) above, wherein the surface of the second barrier film covering the side surface of the recording layer has a curved surface. (4) The recording medium according to (3) above, wherein the maximum film thickness of the second barrier film covering the side surface of the recording layer is 33 μm or less. (5) The recording medium according to (3) or (4) above, wherein the second barrier film on the side surface of the recording layer has different curvatures on the one surface side and the other surface side. (6) The thickness of the second barrier film extending on the one surface is 10 μm or less, and the recording medium according to any one of (1) to (5) above. (7) The width of the second barrier film extending on the one surface and the other surface is 33 μm or less from the end of the recording layer, and the recording medium according to any one of (1) to (6) above. (8) The surface hardness of the second barrier film is 6H or more, and the recording medium according to any one of (1) to (7) above. (9) The silsesquioxane skeleton is represented by any one of the following formulas (1) to (5), Any one of (1) to (8) above the recording medium described in.

Chemical formula

Chemical formula

[0118] This application claims priority based on Japanese Patent Application No. 2019-239314 filed with the Japan Patent Office on December 27, 2019, and incorporates the entire contents of this application by reference.

[0119] Those skilled in the art can conceive of various modifications, combinations, sub-combinations, and changes according to design requirements and other factors, but it is understood that they are included within the scope of the appended claims and their equivalents.

Claims

1. A recording layer containing a leuco dye as a color-forming compound, A first barrier film provided on one surface of the recording layer and the other surface opposite to the one surface, suppressing the incorporation of at least one of moisture and oxygen, A second barrier film having chemical resistance and continuously provided on the side surface of the recording layer from the peripheral portion of the one surface of the recording layer to the peripheral portion of the other surface, The second barrier film contains an ultraviolet curable resin, The ultraviolet curable resin is an organic-inorganic hybrid material, The organic-inorganic hybrid material has a silsesquioxane skeleton represented by the composition formula [(RSiO 1.5 ) n ] A recording medium.

2. The film thickness of the second barrier film covering the side surface of the recording layer is 16 μm or more and 33 μm or less. The recording medium according to claim 1.

3. The surface of the second barrier film covering the side surface of the recording layer has a curved surface. The recording medium according to claim 1.

4. The maximum film thickness of the second barrier film covering the side surface of the recording layer is 33 μm or less. The recording medium according to claim 3.

5. The second barrier film on the side surface of the recording layer has different curvatures on the one surface side and the other surface side. The recording medium according to claim 3.

6. The film thickness of the second barrier film extending on the one surface is 10 μm or less. The recording medium according to claim 1.

7. The width of the second barrier film extending on the one surface and the other surface is 33 μm or less from the end of the recording layer. The recording medium according to claim 1.

8. The second barrier film has durability with a hardness of 6H or more. The recording medium according to claim 1.

9. The silsesquioxane skeleton is represented by any one of the following formulas (1) to (5), and the recording medium according to claim 1. 【Chemical formula 1】 【Chemical formula 2】

10. The side surface of the recording layer is inclined, and the recording medium according to claim 1.

11. The first barrier film has a water vapor transmission rate of 0.001 g / m ２ / day or more and 10 g / m ２ / day or less, and the recording medium according to claim 1.

12. On the first barrier film provided on one surface of the recording layer, there is further provided at least one of an ultraviolet absorption layer and a hard coat layer, and the recording medium according to claim 1.

13. The recording layer is composed of a plurality of layers exhibiting different colors, and the recording medium according to claim 1.

14. The recording layer has one or both of a reversible recording layer and an irreversible recording layer, and the recording medium according to claim 1.

15. At least, a support substrate provided with a recording medium is provided, The recording medium is, A recording layer containing a leuco dye as a color-developing compound, A first barrier film provided on one surface of the recording layer and the other surface facing the one surface, suppressing the incorporation of at least one of moisture and oxygen, It has chemical resistance and a second barrier film continuously provided on the side surface of the recording layer from the peripheral portion of at least the one surface of the recording layer to the peripheral portion of the other surface, The second barrier film contains an ultraviolet curable resin, The ultraviolet curable resin is an organic-inorganic hybrid material, The organic-inorganic hybrid material has a silsesquioxane skeleton represented by the compositional formula [(RSiO1.5)n]. Exterior member.

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