Recording media, laminates, cards, electronic devices, booklets, passports, and wearable devices

Abstract

Provided is a recording medium in which it is possible to suppress any change in color gamut.　The recording medium comprises a plurality of color-generating layers and at least one diffusion-suppressing layer. Each of the color-generating layers contains a coloring compound that donates electrons, a developer that receives electrons, and a matrix resin. The diffusion-suppressing layer is provided between adjacent color-generating layers and is capable of suppressing any diffusion of the coloring compound between the adjacent color-generating layers when the recording medium is heated.

Description

[Technical Field]

[0001] This disclosure concerns recording media 、 Laminate equipped with it , cards, electronic devices, booklets, passports and wearable devices Regarding. [Background technology]

[0002] In recent years, as an alternative to printed materials, recording media comprising a color-developing layer containing an electron-donating color-developing compound and an electron-accepting color developer have been developed. Patent Document 1 discloses a recording medium in which multiple color-developing layers are laminated. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2018 / 092488 Brochure [Overview of the project] [Problems that the invention aims to solve]

[0004] However, in recording media with multiple color-producing layers stacked on top of each other, the color gamut can change. Therefore, there is a need to suppress changes in the color gamut.

[0005] The purpose of this disclosure is to provide a recording medium that can suppress changes in color gamut. 、 Laminate equipped with it , cards, electronic devices, booklets, passports and wearable devices The objective is to provide. [Means for solving the problem]

[0006] To address the aforementioned issues, this disclosure The first aspect of The recording medium relating to this is Multiple color-developing layers, At least one diffusion suppression layer and Equipped with, The coloring layer comprises an electron-donating coloring compound, an electron-accepting color developer, and a matrix resin. The diffusion suppression layer is provided between the adjacent color-developing layers. The diffusion suppression layer contains an ultraviolet-curable resin or a thermosetting resin. At least one adhesive layer is provided between the diffusion-suppressing layer and one of the adjacent color-developing layers. The diffusion-suppressing layer can suppress the diffusion of color-developing compounds between adjacent color-developing layers when the recording medium is heated.

[0007] The recording medium relating to the second aspect of this disclosure is Multiple color-developing layers, At least one resin layer and Equipped with, The coloring layer comprises an electron-donating coloring compound, an electron-accepting color developer, and a matrix resin. The resin layer is provided between the adjacent coloring layers. The resin layer contains an ultraviolet-curable resin or a thermosetting resin. At least one adhesive layer is provided between the resin layer and one of the adjacent color-developing layers. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a perspective view of a laminate according to the first embodiment of this disclosure. [Figure 2] Figure 2 is a cross-sectional view along the line II-II in Figure 1. [Figure 3] Figure 3 is a cross-sectional view of the recording medium. [Figure 4] Figure 4 is a cross-sectional view of the recording medium. [Figure 5] Figure 5 shows the test apparatus for the 90-degree peel test. [Figure 6] Figure 6 is a graph showing an example of data obtained from a 90-degree peel test. [Figure 7] Figure 7 is a cross-sectional view of a laminate according to the second embodiment of this disclosure. [Figure 8] Figure 8 is a cross-sectional view of a modified example of the second embodiment of the present disclosure. [Figure 9] Figure 9 is a cross-sectional view of a modified example of the second embodiment of the present disclosure. [Figure 10] Figure 10 is a cross-sectional view of a modified example of the second embodiment of the present disclosure. [Figure 11]Figure 11 is a cross-sectional view of a modified example of the second embodiment of the present disclosure. [Figure 12] Figure 12 is a cross-sectional view of a modified example of the second embodiment of the present disclosure. [Figure 13] Figure 13 is a cross-sectional view of a modified example of the second embodiment of the present disclosure. [Figure 14] Figure 14 is a cross-sectional view of a modified example of the second embodiment of the present disclosure. [Figure 15] Figure 15 is a cross-sectional view of the recording medium. [Figure 16] Figure 16 is a cross-sectional view of the recording medium. [Figure 17] Figure 17 is a cross-sectional view of the recording medium. [Figure 18] Figure 18 is a cross-sectional view of the recording medium. [Figure 19] Figure 19 is a cross-sectional view of the recording medium. [Figure 20] Figure 20 is a cross-sectional view of the recording medium. [Figure 21] Figure 21 is a cross-sectional view of the recording medium. [Figure 22] Figure 22 is a cross-sectional view of the recording medium. [Figure 23] Figure 23A is a plan view of the front of the smartphone. Figure 23B is a plan view of the back of the smartphone. [Figure 24] Figure 24 is a perspective view of a notebook personal computer. [Figure 25] Figure 25 is a perspective view of a cosmetic container. [Figure 26] Figure 26 is a perspective view of the booklet. [Figure 27] Figure 27 is a graph showing the measurement results of the peel strength of the sample. [Figure 28] Figure 28 is a cross-sectional view of the recording medium. [Modes for carrying out the invention]

[0009] Embodiments of this disclosure will be described in the following order. In all the figures of the embodiments described below, the same or corresponding parts will be denoted by the same reference numerals. 1. First Embodiment (Example of a Laminate) 1.1 Structure of the Laminate 1.2 Recording medium configuration 1.3 Method for manufacturing laminates 1.4 Method for recording laminated structures 1.5 Action and Effects 2. Second Embodiment (Example of a Laminate) 2.1 Structure of the Laminate 2.2 Method for manufacturing laminates 2.3 Action and Effects 3. Variations 4. Reference Examples and Embodiments

[0010] <1 First Embodiment> [1.1 Structure of the Laminate] Figure 1 is a perspective view of a laminate 10 according to a first embodiment of the present disclosure. Figure 2 is a cross-sectional view taken along line II-II in Figure 1. The laminate 10 comprises, in order, a base material 11, an adhesive layer 12, a recording medium 20, an adhesive layer 13, and an overlay layer 14. The laminate 10 may be a card such as a security card, a financial settlement card (e.g., a credit card, a cash card, etc.), an ID card (e.g., an employee ID, a membership card, a student ID, etc.), or a personal transaction card (e.g., a prepaid card, a point card, etc.) (hereinafter referred to as "security card, etc.").

[0011] (base material) The base material 11 is a support that supports the recording medium 20. The base material 11 may be a card. The base material 11 may have a color such as white. The base material 11 may have a design, picture, photograph, text, or a combination of two or more of these (hereinafter referred to as "design, etc.") printed on one main surface of the base material 11 on the side where the recording medium 20 etc. is provided.

[0012] The base material 11 includes, for example, plastic. The base material 11 may optionally contain at least one selected from the group consisting of colorants, antistatic agents, flame retardants, and surface modifiers.

[0013] The plastic includes, for example, at least one selected from the group consisting of ester resins, amide resins, olefin resins, vinyl resins, acrylic resins, imide resins, styrene resins, and engineering plastics. If the substrate 11 contains two or more resins, these two or more resins may be mixed, copolymerized, or laminated.

[0014] Ester resins include, for example, at least one selected from the group consisting of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyethylene terephthalate-isophthalate copolymer, and terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer. Amide resins include, for example, at least one selected from the group consisting of nylon 6, nylon 66, and nylon 610. Olefin resins include, for example, at least one selected from the group consisting of polyethylene (PE), polypropylene (PP), and polymethylpentene (PMP). Vinyl resins include, for example, polyvinyl chloride (PVC).

[0015] Acrylic resins include, for example, at least one selected from the group consisting of polyacrylate, polymethacrylate, and polymethyl methacrylate (PMMA). Imide resins include, for example, at least one selected from the group consisting of polyimide (PI), polyamideimide (PAI), and polyetherimide (PEI). Styrene resins include, for example, at least one selected from the group consisting of polystyrene (PS), high-impact polystyrene, acrylonitrile-styrene resin (AS resin), and acrylonitrile-butadiene-styrene resin (ABS resin). Engineering plastics include, for example, at least one selected from the group consisting of polycarbonate (PC), polyarylate (PAR), polysulfone (PSF), polyethersulfone (PES), polyphenylene ether (PPE), polyphenylene sulfide (PPS), polyetherketone (PEK), polyether-etherketone (PEEK), polyphenylene oxide (PPO), and polyethersulfite.

[0016] (Recording medium) The recording medium 20 is configured to change its coloring state in response to an external stimulus. This change in coloring state allows, for example, a design to be recorded on the recording medium 20. The external stimulus is a laser beam. From the viewpoint of improving anti-counterfeiting properties, it is preferable that the change in coloring state is irreversible. That is, it is preferable that the recording medium 20 is write-once, meaning that a design can be written to it only once.

[0017] The recording medium 20 is provided on one main surface of the substrate 11, with an adhesive layer 12 sandwiched between the substrate 11 and the recording medium 20. The recording medium 20 may be in the form of a film. The recording medium 20 has substantially the same shape and substantially the same size as one main surface of the substrate 11.

[0018] (Overlay layer) The overlay layer 14 is provided on the recording medium 20 and covers the recording medium 20. An adhesive layer 13 is sandwiched between the recording medium 20 and the overlay layer 14. The overlay layer 14 protects the internal components of the laminate 10 (i.e., the recording medium 20) and maintains the mechanical reliability of the laminate 10.

[0019] The overlay layer 14 is film-like. The overlay layer 14 is transparent. The overlay layer 14 contains plastic. Examples of plastic materials include those similar to those used for the base material 11. A design or pattern may be printed on at least one main surface of the overlay layer 14.

[0020] (Adhesive layer) Adhesive layer 12 is provided between the substrate 11 and the recording medium 20, and bonds the substrate 11 and the recording medium 20 together. Adhesive layer 13 is provided between the recording medium 20 and the overlay layer 14, and bonds the recording medium 20 and the overlay layer 14 together. Adhesive layers 12 and 13 are transparent. Adhesive layers 12 and 13 contain a thermal adhesive. The thermal adhesive contains a thermosetting resin. The thermosetting resin includes, for example, at least one selected from the group consisting of epoxy resins and urethane resins. The curing temperature of the thermal adhesive is preferably in the temperature range of 100°C to 120°C from the viewpoint of reducing damage to the recording medium 20.

[0021] [1.2 Recording medium configuration] Figure 3 is a cross-sectional view of the recording medium 20. The recording medium 20 comprises a substrate 21, an intermediate layer 32A, a color-developing layer 24, an intermediate layer 32B, a color-developing layer 27, an intermediate layer 32C, and a color-developing layer 30 in this order. More specifically, the recording medium 20 comprises a substrate 21, an adhesive layer 22, a diffusion-suppressing layer 23, a color-developing layer 24, an adhesive layer 25, a diffusion-suppressing layer 26, a color-developing layer 27, an adhesive layer 28, a diffusion-suppressing layer 29, and a color-developing layer 30 in this order. The recording medium 20 may further comprise a protective layer 31 on the color-developing layer 30, as shown in Figure 3. The recording medium 20 may further comprise an intermediate layer 32D between the color-developing layer 30 and the protective layer 31, as shown in Figure 4. More specifically, the recording medium 20 may further comprise an adhesive layer 33 and a diffusion-suppressing layer 34 between the color-developing layer 30 and the protective layer 31, as shown in Figure 4. The base material 21 faces the adhesive layer 12, and the protective layer 31 faces the adhesive layer 13.

[0022] (base material) The substrate 21 is a support for supporting the color-developing layers 24, 27, 30, etc. Preferably, the substrate 11 is made of a material that has excellent heat resistance and excellent dimensional stability in the planar direction. The substrate 21 may have either light-transmitting or light-non-transmitting properties. The substrate 21 may be a rigid substrate such as a wafer, or a flexible thin-layer glass, film, or paper. By using a flexible substrate 21, a flexible (bendable) recording medium 20 can be realized.

[0023] Examples of constituent materials for the base material 21 include inorganic materials, metallic materials, or plastics. Examples of inorganic materials include silicon (Si) and silicon dioxide (SiO₂). X ), silicon nitride (SiN X ) and aluminum oxide (AlO X It includes at least one selected from the group consisting of ) etc. Silicon oxide includes glass and spin-on glass (SOG), etc. Metal materials include, for example, at least one selected from the group consisting of aluminum (Al), nickel (Ni), stainless steel, etc. As for plastics, materials similar to those of the base material 11 can be exemplified.

[0024] Furthermore, a reflective layer (not shown) may be provided on at least one main surface of the substrate 21, or the substrate 21 itself may also function as a reflective layer. Having such a configuration in the substrate 21 enables clearer color display.

[0025] (Middle class) The intermediate layer 32A is provided between the substrate 21 and the color-developing layer 24. The intermediate layer 32A can bond the substrate 21 and the color-developing layer 24 together. The intermediate layer 32A can provide thermal insulation between the substrate 21 and the color-developing layer 24, and may also suppress the diffusion of the constituent materials between the substrate 21 and the color-developing layer 24. The intermediate layer 32A comprises an adhesive layer 22 and a diffusion-suppressing layer 23. The adhesive layer 22 is adjacent to the substrate 21, and the diffusion-suppressing layer 23 is adjacent to the color-developing layer 24.

[0026] The intermediate layer 32B is provided between the color-developing layer 24 and the color-developing layer 27. The intermediate layer 32B can bond the color-developing layer 24 and the color-developing layer 27 together. The intermediate layer 32B can provide thermal insulation between the color-developing layer 24 and the color-developing layer 27, and may also suppress the diffusion of the constituent materials between the color-developing layer 24 and the color-developing layer 27. The intermediate layer 32B comprises an adhesive layer 25 and a diffusion-suppressing layer 26.

[0027] The intermediate layer 32C is provided between the color-developing layer 27 and the color-developing layer 30. The intermediate layer 32C can bond the color-developing layer 27 and the color-developing layer 30 together. The intermediate layer 32C can provide thermal insulation between the color-developing layer 27 and the color-developing layer 30, and may also suppress the diffusion of the constituent materials between the color-developing layer 27 and the color-developing layer 30. The intermediate layer 32C comprises an adhesive layer 28 and a diffusion-suppressing layer 29.

[0028] The intermediate layer 32D is provided between the color-developing layer 30 and the protective layer 31. The intermediate layer 32D can bond the color-developing layer 30 and the protective layer 31 together. The intermediate layer 32D can provide thermal insulation between the color-developing layer 30 and the protective layer 31, and may also suppress the diffusion of the constituent materials between the color-developing layer 30 and the protective layer 31. The intermediate layer 32D comprises an adhesive layer 33 and a diffusion-suppressing layer 34.

[0029] (Coloring layer) The color-developing layers 24, 27, and 30 are configured to change their color state in response to external stimuli such as laser light or heat. The color-developing layers 24, 27, and 30 are constructed using materials that allow for stable recording and control of the color-developing state. The color-developing layers 24, 27, and 30 include an electron-donating color-developing compound, an electron-accepting color developer corresponding to the color-developing compound, a matrix polymer (binder), and a photothermal conversion material. The color-developing layers 24, 27, and 30 may optionally include, in addition to the above materials, at least one additive selected from the group consisting of, for example, sensitizers and ultraviolet absorbers.

[0030] The color-developing layers 24, 27, and 30 contain color-developing compounds with different color hues. That is, the color-developing compounds contained in the color-developing layers 24, 27, and 30 exhibit different colors in the color-developed state. For example, the color-developing compound contained in color-developing layer 24 exhibits a cyan color in the color-developed state. For example, the color-developing compound contained in color-developing layer 27 exhibits a magenta color in the color-developed state. For example, the color-developing compound contained in color-developing layer 30 exhibits a yellow color in the color-developed state. The photothermal conversion materials contained in color-developing layers 24, 27, and 30 absorb laser light in different wavelength ranges (for example, different near-infrared laser light) and generate heat.

[0031] The thickness of each color-developing layer 24, 27, and 30 is preferably 1 μm to 20 μm, and more preferably 2 μm to 15 μm. If each color-developing layer 24, 27, and 30 has a thickness of 1 μm or more, sufficient color density can be obtained. On the other hand, if each color-developing layer 24, 27, and 30 has a thickness of 20 μm or less, it is possible to suppress the excessive heat utilization of each color-developing layer 24, 27, and 30. Therefore, deterioration of color development can be suppressed.

[0032] (color-forming compound) The color-producing compound is, for example, a leuco dye. The leuco dye may be, for example, an existing dye for thermal paper. A specific example is a compound represented by the following formula (1), which contains an electron-donating group in its molecule.

[0033] [ka]

[0034] There are no particular restrictions on the color-developing compounds, and they can be appropriately selected depending on the purpose. Specific examples of color-developing compounds include, in addition to the compound shown in formula (1) above, fluorane compounds, triphenylmethanephthalide 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-(Nn-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-(Nn-amyl-N-methylamino)fluorane, 2-anilino-3-methyl-6-(N-sec-butyl-N-methylamino)fluorane, 2-anilino-3-methyl-6-(Nn-amyl-N-ethylamino)fluorane, 2-anilino-3-methyl-6-( N-iso-amyl-N-ethylamino)fluorane, 2-anilino-3-methyl-6-(Nn-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-dimethylanilino)-3-methyl-6-diethylaminofluorane, 2-(N-ethyl-p-toluidino)-3-methyl-6-(N-ethylanilino)fluorane, 2-(N-ethyl-p-toluidino)-3-methyl-6-(N-propyl-p-toluidino)fluorane, 2-anilino-6-(Nn-hexyl-N-ethylamino)fluorane, 2-(o-chloroanilino)-6-diethylaminofluorane, 2-(o-chloroanilino)-6-dibutylaminofluorane, 2-(m-trifluoromethylanilino)-6-diethylaminofluorane, 2,3-dimethyl-6-dimethylaminofluorane, 3-methyl-6-(N-ethyl-p-toluidino)fluorane, 2-chloro-6 -Diethylaminofluorane, 2-bromo-6-diethylaminofluorane, 2-chloro-6-dipropylaminofluorane, 3-chloro-6-cyclohexylaminofluorane, 3-bromo-6-cyclohexylaminofluorane, 2-chloro-6-(N-ethyl-N-isoamylamino)fluorane, 2-chloro-3-methyl-6-diethylaminofluorane, 2-anilino-3-chloro-6-diethylaminofluorane, 2-(o-chloroanilino)-3-chloro-6-cyclohexylaminofluorane, 2-(m-trifluoromethylanilino)-3-chloro-6-diethylaminofluorane, 2-(2,3-dichloroanilino)-3-chloro-6-diethylaminofluorane, 1,2-Benzo-6-diethylaminofluorane, 3-diethylamino-6-(m-trifluoromethylanilino)fluorane, 3-(1-ethyl-2-methylindole-3-yl)-3-(2-ethoxy-4-diethylaminophenyl)-4-azaphthalide, 3-(1-ethyl-2-methylindole-3-yl)-3-(2-ethoxy-4-diethylaminophenyl)-7-azaphthalide, 3-(1-octyl- 2-methylindole-3-yl)-3-(2-ethoxy-4-diethylaminophenyl)-4-azaphthalide, 3-(1-ethyl-2-methylindole-3-yl)-3-(2-methyl-4-diethylaminophenyl)-4-azaphthalide, 3-(1-ethyl-2-methylindole-3-yl)-3-(2-methyl-4-diethylaminophenyl)-7-azaphthalide, 3-(1-ethyl-2-methylin Dol-3-yl)-3-(4-diethylaminophenyl)-4-azaphthalide, 3-(1-ethyl-2-methylindole-3-yl)-3-(4-Nn-amyl-N-methylaminophenyl)-4-azaphthalide, 3-(1-methyl-2-methylindole-3-yl)-3-(2-hexyloxy-4-diethylaminophenyl)-4-azaphthalide, 3,3-bis(2-ethoxy-4-diethylaminophenyl) Phenyl)-4-azaphthalide, 3,3-bis(2-ethoxy-4-diethylaminophenyl)-7-azaphthalide, 2-(p-acetylanilino)-6-(Nn-amyl-Nn-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-dimethylanilino)fluorane, 2-benzylamino-6-(N-methyl-p-toluidino)fluorane, 2-benzylamino-6-(N-ethyl-p-toluidino)fluorane, 2-(di-p-methylbenzylamino)-6-(N-ethyl-p-toluidino)fluorane, 2-(α-phenylethylamino)-6-(N-ethyl-p-toluidino)fluorane, 2-methylamino-6-(N-methylanilino)fluorane, 2-methylamino-6-(N-ethylanilino)fluorane, 2-methylamino-6-(N-propylanilino)fluorane , 2-ethylamino-6-(N-methyl-p-toluidino)fluorane, 2-methylamino-6-(N-methyl-2,4-dimethylanilino)fluorane, 2-ethylamino-6-(N-ethyl-2,4-dimethylanilino)fluorane, 2-dimethylamino-6-(N-methylanilino)fluorane, 2-dimethylamino-6-(N-ethylanilino)fluorane, 2-diethylamino-6-(N-methyl-p-toluidino)fluorane, 2-diethylamino-6-(N-ethyl-p-toluidino)fluorane, 2-dipropylamino-6-(N-methyl Fluoranilino)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-ethylanilino)fluoran (Tyl-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)fluorane, 1,2-benzo-6-dibutylaminofluorane, 1,2-benzo-6-(N-methyl-N-cyclohexylamino)fluorane, and 1,2-benzo-6-(N-ethyl-N-toluidino)fluorane. Each of the color-developing layers 24, 27, and 30 may contain one of the above color-developing compounds alone, or two or more.

[0035] (Color developer) A color developer is used, for example, to develop the color of a colorless color-developing compound. The color developer may be in particulate form. Examples of color developers include at least one selected from the group consisting of phenol derivatives, salicylic acid derivatives, and urea derivatives. Specifically, examples include hydroxybenzoic acid type compounds shown in formula (2) below, which contain an electron-accepting group in the molecule. The hydroxybenzoic acid type compound may also be a bis(hydroxybenzoic acid) type compound.

[0036] [ka] (However, X is one of the following: -NHCO-, -CONH-, -NHCONH-, -CONHCO-, -NHNHCO-, -CONHNH-, -CONHNHCO-, -NHCOCONH-, -NHCONHCO-, -CONHCONH-, -NHNHCONH-, -NHCONHNH-, -CONHNHCONH-, -NHCONHNHCO-, and -CONHNHCONH-. R is a linear hydrocarbon group having 25 to 34 carbon atoms.)

[0037] The bonding positions of the hydroxyl group (-OH), carboxyl group (-COOH), and -XR group in formula (2) are not limited. For example, a hydroxybenzoic acid type compound may have a structure in which the hydroxyl group and carboxyl group are bonded to the ortho position of benzene, i.e., a salicylic acid skeleton.

[0038] (Matrix polymer) The matrix polymer (matrix resin) preferably functions as a binder. The matrix polymer is preferably one in which the color-developing compound, color developer, and photothermal conversion material can be homogeneously dispersed. Examples of matrix polymers include at least one selected from the group consisting of thermosetting resins and thermoplastic resins. Specifically, examples include at least one selected from the group consisting of polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate copolymer resins, ethylcellulose resins, polystyrene resins, styrene copolymer resins, phenoxy resins, polyester resins, aromatic polyester resins, polyurethane resins, polycarbonate resins, polyacrylic acid ester resins, polymethacrylate resins, acrylic acid copolymer resins, maleic acid polymer resins, polyvinyl alcohol resins, modified polyvinyl alcohol resins, hydroxyethylcellulose resins, carboxymethylcellulose resins, and starch.

[0039] The matrix polymer preferably contains a polycarbonate resin. The inclusion of a polycarbonate resin in the matrix polymer improves the light resistance of the surface of the recording medium 20. Here, a polycarbonate resin is a resin having at least a carbonate group (-O-(C=O)-O-) as a structural unit in its main chain. Therefore, it may also have other structural units in addition to the carbonate group in its main chain.

[0040] The ratio of the color developer to the total amount of the color developer and matrix resin is, for example, less than 18% by mass, preferably 17% by mass or less, or 16% by mass or less. When the ratio of the color developer is less than 18% by mass, the adhesion between the color development layers 24, 27, and 30 and the layers adjacent to the color development layers 24, 27, and 30 (especially the diffusion suppression layers 23, 26, 29, and 34 (see Figure 15)) can be improved.

[0041] The ratio of the color developer to the total amount of the matrix resin is measured as follows: The composition of the color developer and matrix polymer in color layers 24, 27, and 30 is measured by mapping using a Fourier transform infrared spectrophotometer (micro FTIR). Alternatively, it can be calculated by measuring the weight of each while dissolving them in an appropriate organic solvent, taking advantage of the difference in solubility between the color developer and the matrix polymer.

[0042] From the viewpoint of improving the adhesion between the color-developing layers 24, 27, and 30 and the layers adjacent to them (especially the diffusion-suppressing layers 23, 26, 29, and 34 (see Figure 15)), it is preferable that the matrix polymer content in the color-developing layers 24, 27, and 30 be 84% by mass or more. From the viewpoint of suppressing a decrease in the color development of the color-developing layers 24, 27, and 30, the matrix polymer content is preferably 50% by mass or more and 70% by mass or less, more preferably 58% by mass or more and 65% by mass or less. When the matrix polymer content is 50% by mass or more and 70% by mass or less, it is preferable to select layers adjacent to the color-developing layers 24, 27, and 30 to obtain good adhesion.

[0043] The matrix polymer content in color-developing layers 24, 27, and 30 is measured as follows: The composition of the developer and matrix polymer in color-developing layers 24, 27, and 30 is measured by mapping using a Fourier transform infrared spectrophotometer (micro FTIR). Alternatively, it can be calculated by measuring the weight of each while dissolving them in an appropriate organic solvent, taking advantage of the difference in solubility between the developer and the matrix polymer.

[0044] (Photothermal conversion material) Photothermal conversion materials are, for example, materials that absorb light in a predetermined wavelength range in the near-infrared region and generate heat. Preferably, the photothermal conversion material is a near-infrared absorbing dye that has an absorption peak in the wavelength range of 700 nm to 2000 nm and has almost no absorption in the visible region. Specifically, examples include at least one selected from the group consisting of compounds having a phthalocyanine skeleton (phthalocyanine dyes), compounds having a squarylium skeleton (squarylium dyes), and inorganic compounds. Examples of inorganic compounds include at least one selected from the group consisting of metal complexes such as dithio complexes, diimonium salts, aminium salts, and inorganic compounds. Examples of inorganic compounds include at least one selected from the group consisting of graphite, carbon black, metal powder particles, cobalt tetroxide, iron oxide, chromium oxide, copper oxide, titanium black, metal oxides such as ITO (Indium Tin Oxide), metal nitrides such as niobium nitride, metal carbides such as tantalum carbide, metal sulfides, and various magnetic powders. In addition, compounds having a cyanine skeleton with excellent lightfastness and heat resistance (cyanine dyes) may be used. Here, excellent lightfastness means that the compound does not decompose under the usage environment, for example, when exposed to light from a fluorescent lamp. Excellent heat resistance means that, for example, when formed into a film with a polymer material and stored at 150°C for 30 minutes, the maximum absorption peak value of the absorption spectrum does not change by more than 20%. Examples of compounds having such a cyanine skeleton include those having at least one of the following counterions in the molecule: SbF6, PF6, BF4, ClO4, CF3SO3, and (CF3SO3)2N, and a methine chain containing a five-membered ring or a six-membered ring. In the first embodiment, it is preferable that the cyanine skeleton compound used in the recording medium 20 has both one of the above counterions and a cyclic structure such as a five-membered ring or a six-membered ring in the methine chain, but sufficient lightfastness and heat resistance are ensured if at least one of them is present.

[0045] Furthermore, it is preferable to select a photothermal conversion material that has a narrow light absorption band in the wavelength range of 700 nm to 2000 nm, and in which the light absorption bands of the color-developing layers 24, 27, and 30 do not overlap with each other. This makes it possible to selectively color a desired layer among the color-developing layers 24, 27, and 30.

[0046] (Diffusion suppression layer) The diffusion-suppressing layer 23 is provided between the substrate 21 and the color-developing layer 24, and can suppress the diffusion of substances (e.g., color-developing compounds, etc.) between the substrate 21 and the color-developing layer 24, and can also provide insulation between the substrate 21 and the color-developing layer 24. The diffusion-suppressing layer 26 is provided between the color-developing layer 24 and the color-developing layer 27, and can suppress the diffusion of substances (e.g., color-developing compounds, etc.) between the color-developing layer 24 and the color-developing layer 27, and can also provide insulation between the color-developing layer 24 and the color-developing layer 27. The diffusion-suppressing layer 29 is provided between the color-developing layer 27 and the color-developing layer 30, and can suppress the diffusion of substances (e.g., color-developing compounds, etc.) between the color-developing layer 27 and the color-developing layer 30, and can also provide insulation between the color-developing layer 27 and the color-developing layer 30. The diffusion suppression layer 34 is provided between the color-developing layer 30 and the protective layer 31, and can suppress the diffusion of substances (e.g., color-developing compounds, etc.) between the color-developing layer 30 and the protective layer 31, and can also provide heat insulation between the color-developing layer 30 and the protective layer 31.

[0047] The diffusion-suppressing layers 23, 26, 29, and 34 are, for example, layers containing amorphous resin or crystalline resin. The diffusion-suppressing layers 23, 26, 29, and 34 include, for example, general translucent polymer materials. Specific materials include, for example, at least one selected from the group consisting of acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate copolymer resins, ethylcellulose resins, polystyrene resins, styrene copolymer resins, phenoxy resins, polyester resins, aromatic polyester resins, polyurethane resins, polycarbonate resins, polyacrylic acid ester resins, polymethacrylate ester resins, acrylic acid copolymer resins, maleic acid polymer resins, polyvinyl alcohol resins, modified polyvinyl alcohol resins, hydroxyethylcellulose resins, carboxymethylcellulose resins, and starch. The diffusion-suppressing layers 23, 26, 29, and 34 may also contain various additives, such as ultraviolet absorbers. The diffusion-suppressing layers 23, 26, 29, and 34 may be films containing a light-transmitting polymer material.

[0048] The diffusion-inhibiting layers 23, 26, 29, and 34 are preferably UV-curable resin layers or thermosetting resin layers. The UV-curable resin layer contains a UV-curable resin composition that has undergone a polymerization reaction and solidified. More specifically, for example, the UV-curable resin layer contains a polymer of a polymerizable compound and a polymer initiator that has undergone a structural change by generating active species upon irradiation with external energy (ultraviolet light). The UV-curable resin composition includes, for example, at least one selected from the group consisting of radical polymerization type UV-curable resin compositions and cationic polymerization type UV-curable resin compositions. The UV-curable resin composition may optionally contain at least one selected from the group consisting of sensitizers, fillers, stabilizers, leveling agents, defoamers, and viscosity modifiers. The UV-curable resin composition may be a UV-curable resin composition for hard coats. The UV-curable resin composition may be an acrylic-based UV-curable resin composition.

[0049] UV-curable resin compositions are classified into two types based on their reaction mechanism: radical polymerization and cationic polymerization. In radical polymerization, radicals are generated from the initiator upon UV absorption, and acrylate resins or acrylate monomers containing acryloyl groups in their molecules undergo radical polymerization. Special functional groups such as acryloyl groups can be detected by FT-IR. Alternatively, the radical polymerization agent can be detected by sublimation using GC-MS. Generally, the radical polymerization agent is added in excess to ensure sufficiently rapid polymerization. In cationic polymerization, the initiator generates acid upon UV absorption, and vinyl monomers, cyclic ethers, etc., initiate cationic polymerization. Special functional groups such as vinyl groups, ether groups, and epoxy groups can be detected by FT-IR. Radical polymerization is preferred due to cost and the high selectivity of monomers, but cationic polymerization is also acceptable.

[0050] The thermosetting resin layer contains a thermosetting resin composition that has undergone a polymerization reaction and solidified. In the case of thermosetting resin compositions, epoxy groups can also be detected by FT-IR. UV-curing types are advantageous for coatings because they allow for rapid and uniform curing of the composition and a higher degree of crosslinking. The degree of crosslinking can be determined by dissolving the polymer portion and calculating the monomer ratio of the resulting components.

[0051] The diffusion-suppressing layers 23, 26, 29, and 34 may contain a translucent inorganic material. For example, using porous silica, alumina, titania, carbon, or composites thereof is preferable because it has low thermal conductivity and a high heat-insulating effect. The diffusion-suppressing layers 23, 26, 29, and 34 can also be formed, for example, by the sol-gel method.

[0052] The thickness of the diffusion-suppressing layers 23, 26, 29, and 34 is preferably 3 μm to 100 μm, more preferably 5 μm to 50 μm. If the thickness of the diffusion-suppressing layers 23, 26, 29, and 34 is 3 μm or more, sufficient diffusion-suppressing effect and heat insulation effect can be obtained. On the other hand, if the thickness of the diffusion-suppressing layers 23, 26, 29, and 34 is 100 μm or less, a decrease in light transmittance can be suppressed. Furthermore, a decrease in the bending resistance of the recording medium 20 can be suppressed, making it less likely for defects such as cracks to occur.

[0053] The diffusion-suppressing layer 26 can suppress the diffusion of substances (e.g., color-developing compounds) between adjacent color-developing layers 24 and 27 when the recording medium 20 is heated. The diffusion-suppressing layer 29 can suppress the diffusion of substances (e.g., color-developing compounds) between adjacent color-developing layers 27 and 30 when the recording medium 20 is heated. The diffusion-suppressing layer 23 can suppress the diffusion of substances (e.g., color-developing compounds) between adjacent substrate 21 and color-developing layer 24 when the recording medium 20 is heated. The diffusion-suppressing layer 34 can suppress the diffusion of substances (e.g., color-developing compounds) between adjacent color-developing layer 30 and protective layer 31 when the recording medium 20 is heated. The heating temperature of the recording medium 20 is preferably 120°C to 200°C or 160°C to 200°C. Here, the heating temperature of the recording medium 20 is the temperature measured on the surface of the laminate 10 or the recording medium 20.

[0054] The diffusion of chromogenic compounds (e.g., leuco dyes) can be measured using TOF-SIMS. The molecular weight of the chromogenic compound is determined from the chromogenic layers 24, 27, and 30 using LC-MS or similar methods. Then, the measurement area is extracted, and the recording medium 20 is etched in the film thickness direction by sputtering, extracting the spectrum corresponding to the molecular weight of the chromogenic compound. Next, the change in the molecular fragment intensity of the chromogenic compound is compared before and after heating, in comparison with the chromogenic layers 24, 27, and 30.

[0055] The pencil hardness of the surfaces of the diffusion-inhibiting layers 23, 26, 29, and 34 is preferably 2B or higher, more preferably H or higher. When the pencil hardness of the surfaces of the diffusion-inhibiting layers 23, 26, 29, and 34 is 2B or higher, the crosslinking density of the diffusion-inhibiting layers 23, 26, 29, and 34 is high, resulting in high density and further suppression of substance diffusion through the intermediate layers 32A, 32B, 32C, and 32D. For example, when the pencil hardness of the surfaces of the diffusion-inhibiting layers 26 and 29 is 2B or higher, the diffusion of the color-developing compound through the intermediate layers 32B, 32C, and 32D can be further suppressed. Therefore, the change in hue of the color-developing layers 24, 27, and 30 during long-term storage can be further suppressed. As the diffusion-inhibiting layers 23, 26, 29, and 34 having the above-mentioned pencil hardness, ultraviolet-curable resin layers or thermosetting resin layers are preferred.

[0056] The pencil hardness of the surface of the diffusion-suppressing layer 23 is measured as follows: First, the laminate 10 is disassembled to expose the surface of the diffusion-suppressing layer 23. Next, the pencil hardness of the surface of the diffusion-suppressing layer 23 is measured in accordance with JIS K5600-5-4. This measurement is performed in a standard atmosphere with a temperature of 23±1℃ and a relative humidity of 50±5%. The pencil hardness of the surfaces of the diffusion-suppressing layers 26, 29, and 34 is measured using the same procedure as the pencil hardness of the surface of the diffusion-suppressing layer 23.

[0057] The diffusion-inhibiting layers 23, 26, 29, and 34 are preferably resin layers that do not have tackiness. This improves the diffusion-inhibiting effect of the diffusion-inhibiting layers 23, 26, 29, and 34.

[0058] The Young's modulus of the diffusion-suppressing layers 23, 26, 29, and 34 is preferably 10 MPa or higher, more preferably 100 MPa or higher, and even more preferably 2000 MPa or higher, in a standard atmosphere with a temperature of 23±1°C and a relative humidity of 50±5%. When the Young's modulus of the diffusion-suppressing layers 23, 26, 29, and 34 is 10 MPa or higher, the effect of the diffusion-suppressing layers 23, 26, 29, and 34 in suppressing material diffusion can be improved.

[0059] The Young's modulus of the diffusion-suppressing layers 23, 26, 29, and 34 is measured as follows: Using a tensile testing machine, the Young's modulus is determined from the ratio of the tensile stress within the tensile proportional limit of the material to the corresponding strain.

[0060] The diffusion-suppressing layers 23, 26, 29, and 34 are preferably resin layers with a glass transition temperature of 130°C or higher. Having a glass transition temperature of 130°C or higher improves the diffusion-suppressing effect of the diffusion-suppressing layers 23, 26, 29, and 34. From the viewpoint of improving the diffusion-suppressing effect, the diffusion-suppressing layers 23, 26, 29, and 34 may be resin layers that are solid at room temperature and do not have a phase transition point within the range of 25°C to 300°C.

[0061] The glass transition temperatures of the diffusion-suppressing layers 23, 26, 29, and 34 are measured as follows: The glass transition temperatures of the diffusion-suppressing layers 23, 26, 29, and 34 are measured by obtaining the peak shift of the thermal history using thermogravimetric differential thermal analysis (TG-DTA).

[0062] (Adhesive layer) The adhesive layer 22 is provided between the substrate 21 and the diffusion suppression layer 23, and bonds the substrate 21 and the diffusion suppression layer 23 together. The adhesive layer 25 is provided between the color development layer 24 and the diffusion suppression layer 26, and bonds the color development layer 24 and the diffusion suppression layer 26 together. The adhesive layer 28 is provided between the color development layer 27 and the diffusion suppression layer 29, and bonds the color development layer 27 and the diffusion suppression layer 29 together. The adhesive layer 33 is provided between the color development layer 30 and the diffusion suppression layer 34, and bonds the color development layer 30 and the diffusion suppression layer 34 together.

[0063] The adhesive layers 22, 25, 28, and 33 contain an adhesive. The adhesive includes, for example, at least one selected from the group consisting of acrylic resins, silicone resins, urethane resins, epoxy resins, and elastomer materials. The adhesive layers 22, 25, 28, and 33 may also be optical adhesive sheets such as OCA (Optical Clear Adhesive).

[0064] (protective layer) The protective layer 31 is for protecting the surface of the recording medium 20 and is formed using, for example, at least one of ultraviolet-curable resins and thermosetting resins. The protective layer 31 is preferably a hard coat layer. The thickness of the protective layer 31 is, for example, 0.1 μm or more and 20 μm or less. In addition to the function of protecting the surface of the recording medium 20A, the protective layer 31 may also have the function of cutting ultraviolet rays incident on the coloring layers 24, 27, and 30. In this case, the protective layer 31 may include a resin layer and a UV-cut layer. Specifically, for example, the protective layer 31 may sequentially provide a resin layer, a UV-cut layer, an adhesive layer, and a substrate on one main surface of the coloring layer 30. The resin layer includes, for example, at least one of ultraviolet-curable resins and thermosetting resins. The resin layer is preferably a hard coat layer.

[0065] (Average peel strength between layers) The average peel strength at the interfaces between each layer constituting the laminate 10 is preferably 3.5 N / cm or more, more preferably 4.0 N / cm or more, even more preferably 4.5 N / cm or more, and particularly preferably 5.0 N / cm or more. When the average peel strength at the interfaces between each layer is 3.5 N / cm or more, peeling at the interfaces between each layer constituting the laminate 10 can be suppressed. Therefore, the anti-counterfeiting and anti-tampering properties of the laminate 10 can be improved. Here, each layer constituting the laminate 10 may include each layer constituting the recording medium 20.

[0066] The average peel strength of at least one interface among the interfaces included in the recording medium 20 may preferably be less than 3.5 N / cm, and more preferably less than 3.0 N / cm. When the laminate 10 is disassembled, the recording medium 20 disassembles, making it difficult to remove and use the recording medium 20.

[0067] If the average peel strength of at least one interface among those included in the recording medium 20 is less than 3.5 N / cm, then the average peel strength of the interface between the substrate 11 and the recording medium 20, and the average peel strength of the interface between the recording medium 20 and the overlay layer 14 are preferably 3.5 N / cm or more, more preferably 4.0 N / cm or more, even more preferably 4.5 N / cm or more, and particularly preferably 5.0 N / cm or more. As a result, when the laminate 10 is disassembled, the recording medium 20 is easily damaged, making it difficult to remove and use the recording medium 20.

[0068] In the recording medium 20, the average peel strength of at least one interface among the interfaces between adjacent color-developing layers 24 and 27, and between adjacent color-developing layers 27 and 30, is preferably less than 3.5 N / cm, more preferably less than 3.0 N / cm. If the average peel strength of the recording medium 20 is less than 3.5 N / cm, when the laminate 10 is disassembled, the recording medium 20 will disassemble between the color-developing layers 24 and 27, or between the color-developing layers 27 and 30, making it difficult to remove and use the recording medium 20.

[0069] If the average peel strength of at least one interface among the interfaces between adjacent color-developing layers 24 and 27, and between adjacent color-developing layers 27 and 30 is less than 3.5 N / cm, then the average peel strength of the interface between the substrate 11 and the recording medium 20, and the average peel strength of the interface between the recording medium 20 and the overlay layer 14 are preferably 3.5 N / cm or more, more preferably 4.0 N / cm or more, even more preferably 4.5 N / cm or more, and particularly preferably 5.0 N / cm or more. As a result, when the laminate 10 is disassembled, the recording medium 20 is easily damaged, making it difficult to remove and use the recording medium 20.

[0070] The average peel strength at the interface between each layer is determined by performing a 90-degree peel test. Since the method for measuring the average peel strength at the interface between each layer is the same, only the method for measuring the average peel strength at the interface between the substrate 11 and the recording medium 20 will be described below with reference to Figure 5.

[0071] First, the laminate 10 is cut into strips 10 mm wide and 100 mm long to prepare test pieces 60, which are left in a standard atmosphere of 23 ± 1 °C and 50 ± 5% relative humidity for 24 hours or more. Hereinafter, the laminate portion of the test piece 60 above the interface between the base material 11 and the recording medium 20 will be referred to as the adherend 61. Next, at one end of the test piece 60 in the longitudinal direction, a notch is made between the base material 11 and the adherend 61 using a sharp blade such as a cutter, and the adherend 61 is peeled off in the longitudinal direction for a length of 20 mm to create a gripping area. Then, the side of the test piece 60 facing the base material 11 is fixed to the test stand 71 with a strong adhesive. As for the adhesive, one with sufficiently high adhesive strength is selected so that the base material 11 does not peel off from the test stand 71 when measuring the peel strength between the base material 11 and the adherend 61, such as 3M's Scotch® strong adhesive tape. Figure 5 shows an example where the tension member 62 is used as a gripping space. However, if there is sufficient stroke before the adherend 61 is clamped by the clamping device (metal plate) 63, the adherend 61 may be clamped directly without using the tension member 62. The tension member 62 is a strip of film with sufficient strength so as not to elongate or break during the measurement of the peel strength. In addition, one end of the tension member 62 is attached to the adherend 61 with sufficiently high adhesive force so as not to peel off from the adherend 61 during the measurement of the peel strength.

[0072] Next, the gripping portion of the tensile member 62 is passed between a pair of movable rolls 73A and 73B of the jig 72, and then the gripping portion is clamped and fixed by 10 mm or more using the clamping device (metal plate) 63 of the SV-55C 2H tensile and compression testing machine manufactured by Imada Seisakusho Co., Ltd. The movable rolls 73A and 73B serve as the fulcrum for peeling during the 90-degree peel test. Next, the 90-degree peel test is performed using the tensile and compression testing machine, and the test force [N / cm] and stroke [mm] are monitored as voltage values, for example, using a data logger manufactured by Keyence Corporation, converted to force, and stored in memory as CSV output data. The above 90-degree peel test is performed at a tensile speed of 5 mm / sec. under standard conditions of a temperature of 23 ± 1°C and a relative humidity of 50 ± 5%. The stroke is set to 50 mm or more.

[0073] The above 90-degree peel test is performed a total of three times. The point where the peel strength is stable (the position where the force rises gradually) is used as the starting point (0 mm), and the CSV output data from that point to a relative distance of 50 mm is arithmetic mean to calculate the average value. This allows the average peel strength between the substrate 11 and the recording medium 20 (adhered object 61) to be determined. However, points where the peel force suddenly drops (spikes) are excluded from the CSV output data. Figure 6 shows an example of data obtained from the 90-degree peel test.

[0074] (Combination of materials for the base material and overlay layer) From the viewpoint of improving adhesion, it is preferable that the base material 11 and the overlay layer 14 contain the same type of resin material. The resin material may be a thermoplastic resin. From the viewpoint of environmental consideration, it is preferable that the base material 11 and the overlay layer 14 contain polycarbonate (PC) resin or polyethylene terephthalate (PET) resin. From the viewpoint of improving durability, it is preferable that the base material 11 and the overlay layer 14 contain polycarbonate (PC) resin or polyvinyl chloride (PVC) resin. From the viewpoint of improving adhesion, environmental consideration, and durability, it is preferable that the base material 11 and the overlay layer 14 contain polycarbonate (PC) resin.

[0075] The presence of the same type of resin material in the substrate 11 and the overlay layer 14 can be confirmed, for example, as follows: First, the substrate 11 and the overlay layer 14 are removed from the laminate 10. Next, the IR spectra of the substrate 11 and the overlay layer 14 are obtained by infrared absorption spectroscopy (IR). Then, by comparing the obtained IR spectra of each layer, it is confirmed that the substrate 11 and the overlay layer 14 contain the same type of resin material. Furthermore, the types of resin materials contained in the substrate 11 and the overlay layer 14 can be identified using the acquired IR spectra of each layer.

[0076] [1.3 Method for manufacturing laminates] Hereinafter, an example of a method for manufacturing the laminate 10 according to the first embodiment of this disclosure will be described.

[0077] First, a thermosetting resin is applied to the substrate 11 as a thermal adhesive to form an adhesive layer 12. Next, the recording medium 20 is placed on the adhesive layer 12. Then, a thermosetting resin is applied to the recording medium 20 as a thermal adhesive to form an adhesive layer 13, and then an overlay layer 14 is placed on the adhesive layer 13. Next, the resulting laminate is sandwiched between metal plates and heated and pressurized to heat-cur the adhesive layers 12 and 13. The temperature applied to the laminate during heat curing is preferably 100°C to 120°C from the viewpoint of reducing damage to the recording medium 20. This yields the desired laminate 10. The adhesive layer 13 may also be formed by applying a thermosetting resin to the overlay layer 14, and then placing the overlay layer 14 on the recording medium 20 with the coating film in between. Alternatively, the adhesive layer 13 may be formed by bonding a sheet, which has been previously formed by applying a thermosetting resin to the separator, to the overlay layer 14 or the recording medium 20 by means of thermal lamination or the like.

[0078] [1.4 Recording Method for Laminated Structures] In the laminate 10 according to the first embodiment, patterns and the like can be recorded on the recording medium 20 as follows. Here, the case in which the color-developing layers 24, 27, and 30 exhibit cyan, magenta, and yellow colors, respectively, will be described as an example.

[0079] For example, infrared light having a specified wavelength and output is irradiated onto the recording medium 20 via the overlay layer 14 using a semiconductor laser or the like. When coloring the color-developing layer 24, infrared light with wavelength λ1 is irradiated onto the color-developing layer 24 with an energy sufficient to cause the color-developing layer 24 to reach its color-developing temperature. As a result, the photothermal conversion material contained in the color-developing layer 24 generates heat, causing a color reaction (color development reaction) to occur between the color-developing compound and the color developer, and the irradiated area develops a cyan color. Similarly, when coloring the color-developing layer 27, infrared light with wavelength λ2 is irradiated onto the color-developing layer 27 with an energy sufficient to cause the color-developing layer 27 to reach its color-developing temperature. When coloring the color-developing layer 30, infrared light with wavelength λ3 is irradiated onto the color-developing layer 30 with an energy sufficient to cause the color-developing layer 30 to reach its color-developing temperature. As a result, the photothermal conversion materials contained in the color-developing layer 27 and the color-developing layer 30 generate heat, causing a color reaction between the color-developing compound and the color developer, resulting in magenta and yellow colors appearing in the irradiated area, respectively. In this way, by irradiating any area with infrared light of the corresponding wavelength, it becomes possible to record patterns (for example, full-color patterns).

[0080] [1.5 Actions and Effects] As described above, the laminate 10 according to the first embodiment includes an intermediate layer 32B containing a diffusion suppression layer 26 between the color-developing layer 24 and the color-developing layer 27, and an intermediate layer 32C containing a diffusion suppression layer 29 between the color-developing layer 27 and the color-developing layer 30. The diffusion suppression layer 26 can suppress the diffusion of the color-developing compound between the color-developing layer 24 and the color-developing layer 27 when the recording medium 20 is heated. The diffusion suppression layer 29 can suppress the diffusion of the color-developing compound between the color-developing layer 27 and the color-developing layer 30 when the recording medium 20 is heated. This makes it possible to suppress changes in the color gamut of the recording medium 20.

[0081] In the laminate 10 according to the first embodiment, the substrate 11 and the recording medium 20 are bonded together by an adhesive layer 12 containing a thermal adhesive, and the recording medium 20 and the overlay layer 14 are also bonded together by an adhesive layer 12 containing a thermal adhesive. This allows for a strong bond between the substrate 11 and the recording medium 20, and between the recording medium 20 and the overlay layer 14. Therefore, the anti-counterfeiting properties of the laminate 10 can be improved. Furthermore, the tamper-proof properties of the laminate 10 can also be improved. Thus, the security of the laminate 10 can be improved.

[0082] Since the recording medium 20 is equipped with color-developing layers 24, 27, and 30, it can convert photographic images and the like of a laminated body 10 such as a plastic security card into full color. Since the laminate 10 includes the full-color recording medium 20 in a portion of its surface, costs can be reduced compared to the case where the full-color recording medium 20 is included across the entire surface of the laminate 10. Since the recording medium 20 is enclosed inside the laminate 10, the effect of moisture on the recording medium 20 can be reduced.

[0083] <2 Second Embodiment> [2.1 Structure of the Laminate] Figure 7 is a cross-sectional view of a laminate 40 according to a second embodiment of the present disclosure. The laminate 40 differs from the laminate 10 according to the first embodiment in that it does not have adhesive layers 12 and 13, and the substrate 11 and the recording medium 20 and the recording medium 20 and the overlay layer 14 are bonded together by fusion.

[0084] In the second embodiment, it is preferable that the base material 11, the first main surface of the recording medium 20, the second main surface of the recording medium 20, and the overlay layer 14 contain a thermoplastic resin as the plastic. By including a thermoplastic resin in the base material 11, the first main surface of the recording medium 20, the second main surface of the recording medium 20, and the overlay layer 14, the interlayer adhesion strength due to fusion can be strengthened. From the viewpoint of reducing damage to the recording medium 20, it is preferable that the thermoplastic resin is capable of heat-sealing the interlayers of the laminate 40 in a temperature range of 120°C to 200°C.

[0085] The substrate 11, the first main surface of the recording medium 20, the second main surface of the recording medium 20, and the overlay layer 14 may contain the same type of thermoplastic resin, or they may not contain the same type of thermoplastic resin. If the substrate 11, the first main surface of the recording medium 20, the second main surface of the recording medium 20, and the overlay layer 14 do not contain the same type of thermoplastic resin, one or more parts of the substrate 11, the first main surface of the recording medium 20, the second main surface of the recording medium 20, and the overlay layer 14 may contain a different type of thermoplastic resin than the other parts, or each of the substrate 11, the first main surface of the recording medium 20, the second main surface of the recording medium 20, and the overlay layer 14 may each contain different types of thermoplastic resin.

[0086] When the substrate 11, the first main surface of the recording medium 20, the second main surface of the recording medium 20, and the overlay layer 14 contain the same type of thermoplastic resin, it is preferable that the substrate 11, the first main surface of the recording medium 20, the second main surface of the recording medium 20, and the overlay layer 14 contain at least one selected from the group consisting of semicrystalline thermoplastic resins and amorphous thermoplastic resins, from the viewpoint of improving interlayer adhesion strength by fusion.

[0087] The semi-crystalline thermoplastic resin includes, for example, at least one selected from the group consisting of polypropylene (PP), polyethylene (PE), polyacetal (POM), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), and polyether ether ketone (PEEK).

[0088] The amorphous thermoplastic resin includes, for example, at least one selected from the group consisting of ABS resin, polycarbonate (PC), polymer alloy of ABS resin and PC (hereinafter referred to as "ABS / PC polymer alloy"), AS resin, polystyrene (PS), polymethyl methacrylate (PMMA), polyphenylene oxide (PPO), polysulfone (PSU), polyvinyl chloride (PVC), polyetherimide (PEI), and polyethersulfone (PES).

[0089] If the substrate 11, the first main surface of the recording medium 20, the second main surface of the recording medium 20, and the overlay layer 14 do not contain the same type of thermoplastic resin, it is preferable that the substrate 11, the first main surface of the recording medium 20, the second main surface of the recording medium 20, and the overlay layer 14 contain an amorphous thermoplastic resin from the viewpoint of improving interlayer adhesion strength by fusion.

[0090] The following combinations of amorphous thermoplastic resins are preferred for the two adjacent layers of the laminate 40. If one of the two adjacent layers of the laminate 40 contains ABS resin, it is preferable that the other layer contains at least one selected from the group consisting of ABS / PC polymer alloy, polycarbonate (PC), AS resin, polystyrene (PS), polymethyl methacrylate (PMMA), and polyvinyl chloride (PVC).

[0091] If one of two adjacent layers of the laminate 40 contains an ABS / PC polymer alloy, it is preferable that the other layer contains at least one selected from the group consisting of ABS resin, polycarbonate (PC), and polymethyl methacrylate (PMMA).

[0092] If one of two adjacent layers of the laminate 40 contains AS resin, it is preferable that the other layer contains at least one selected from the group consisting of ABS resin, polystyrene (PS), polymethyl methacrylate (PMMA), and polyphenylene oxide (PPO).

[0093] If one of two adjacent layers of the laminate 40 contains polymethyl methacrylate (PMMA), it is preferable that the other layer contains at least one selected from the group consisting of ABS resin, ABS / PC polymer alloy, AS resin, and polyphenylene oxide (PPO). If one of two adjacent layers of the laminate 40 contains polyphenylene oxide (PPO), it is preferable that the other layer contains at least one selected from the group consisting of polycarbonate (PC), AS resin, polystyrene (PS), and polymethyl methacrylate (PMMA).

[0094] If one of two adjacent layers of the laminate 40 contains polysulfone (PSU), it is preferable that the other layer contains polycarbonate (PC). If one of two adjacent layers of the laminate 40 contains polyvinyl chloride (PVC), it is preferable that the other layer contains ABS resin.

[0095] [2.2 Method for manufacturing laminates] Hereinafter, an example of a method for manufacturing the laminate 40 according to the second embodiment of this disclosure will be described.

[0096] First, a recording medium 20 is placed on one main surface of the base material 11, and then an overlay layer 14 is placed on the recording medium 20. Next, the resulting laminate is sandwiched between metal plates and heated and pressed to heat-seal the base material 11 and the recording medium 20, and the recording medium 20 and the overlay layer 14. The temperature applied to the laminate during heat sealing is preferably between 130°C and 200°C, from the viewpoint of reducing damage to the recording medium 20 and achieving sufficient fusion strength. This yields the desired laminate 40.

[0097] [2.3 Effects] As described above, in the laminate 40 according to the second embodiment, the substrate 11 and the recording medium 20 and the recording medium 20 and the overlay layer 14 are fused together. This allows for a strong bond between the substrate 11 and the recording medium 20 and between the recording medium 20 and the overlay layer 14. Therefore, the anti-counterfeiting properties of the laminate 40 can be improved. Furthermore, the tamper-proof properties of the laminate 40 can also be improved. Thus, the security of the laminate 40 can be improved.

[0098] <3 Variations> (Variation 1) In the first and second embodiments, examples were described in which the recording medium 20 covers the entire surface of the first main surface of the substrate 11. However, as shown in Figure 8, the recording medium 20 may have perforations 20HL. In Figure 8, the laminate 40 is shown as an example in which the recording medium 20 has perforations 20HL, but the laminate 10 may also be the recording medium 20 having perforations 20HL.

[0099] The hole 20HL penetrates the recording medium 20 in the thickness direction. Patterns applied to the substrate 11 may be visible through the hole 20HL, and the functions of the substrate 11 may be expressed through the hole 20HL. A transparent resin layer or the like may be fitted into the hole 20HL to ensure the flatness of one main surface of the recording medium 20. However, the hole 20HL may be in a hollow state.

[0100] (Modification 2) The laminate 40 according to the second embodiment may include an intermediate layer 15 between the substrate 11 and the recording medium 20, as shown in Figure 9. Alternatively, the intermediate layer 15 may be included between the recording medium 20 and the overlay layer 14, as shown in Figure 10. Considering the visibility of the recording medium 20, it is preferable that the laminate 40 includes an intermediate layer 15 between the substrate 11 and the recording medium 20. The intermediate layer 15 may contain, for example, an IC (Integrated Circuit) chip 15A. The intermediate layer 15 may be, for example, a film or an adhesive layer.

[0101] The laminate 10 according to the first embodiment may include an intermediate layer 15 between the substrate 11 and the adhesive layer 12, between the adhesive layer 12 and the recording medium 20, between the recording medium 20 and the adhesive layer 13, or between the adhesive layer 13 and the overlay layer 14.

[0102] (Variation 3) The laminate 40 according to the second embodiment may include a fine-printed layer 16 between the substrate 11 and the recording medium 20, as shown in Figure 11. Alternatively, the laminate may include a fine-printed layer 16 between the recording medium 20 and the overlay layer 14, as shown in Figure 12. Considering the visibility of the recording medium 20, it is preferable that the laminate 40 includes a fine-printed layer 16 between the substrate 11 and the recording medium 20. The fine-printed layer 16 has, for example, a predetermined fine-printed pattern. The fine-printed pattern may be a background pattern or the like.

[0103] The laminate 10 according to the first embodiment may include a fine printing layer 16 between the substrate 11 and the adhesive layer 12, between the adhesive layer 12 and the recording medium 20, between the recording medium 20 and the adhesive layer 13, or between the adhesive layer 13 and the overlay layer 14.

[0104] (Modification 4) In the second embodiment, the laminate 40 may have a barrier layer 17 on its side, as shown in Figure 13. The barrier layer 17 may cover the entire side of the laminate 40, as shown in Figure 13, or it may cover a part of the side of the laminate 40, for example, the side of the recording medium 20, as shown in Figure 14. The barrier layer 17 can protect the side of the laminate 40.

[0105] The barrier layer 17 is, for example, an ultraviolet-curable resin layer or a thermosetting resin layer. By providing the barrier layer 17 on the side surface of the laminate 40, it is possible to suppress the intrusion of moisture and other substances into the recording medium 20 and its subsequent deterioration. The laminate 10 according to the first embodiment may also be provided with the barrier layer 17 on the side surface.

[0106] (Variation 5) In the first and second embodiments, an example was described in which the recording medium 20 comprises three color-developing layers (color-developing layers 24, 27, and 30). However, the recording medium 20 may also comprise a single color-developing layer. In this case, the recording medium 20 may comprise a substrate, an adhesive layer, a color-developing layer, and a protective layer in this order. The color-developing layer may exhibit black color in the color-developed state.

[0107] Furthermore, the recording medium 20 may have more than three color-developing layers (i.e., two color-developing layers or four or more color-developing layers). In this case as well, intermediate layers may be provided between adjacent color-developing layers. Each of the multiple color-developing layers may exhibit a different hue from the others in the color-developing state. That is, the color-developing compounds contained in each of the multiple color-developing layers may exhibit a different hue from the others in the color-developing state. The photothermal converters contained in each of the multiple color-developing layers may have different absorption wavelength peaks from each other.

[0108] (Modification Example 6) In the first and second embodiments, the color developer may contain a compound represented by the following formula (3). [Chemical Formula] (However, in formula (3), X 0 is a divalent group containing at least one benzene ring. Y 01 , Y 02 are each independently a monovalent group. n01 and n02 are each independently an integer from 0 to 5. When n01 is an integer from 2 to 5, Y 01 may be the same as or different from each other. When n02 is an integer from 2 to 5, Y 02 may be the same as or different from each other. Z 01 , Z 02 are each independently a hydrogen-bonding group.)

[0109] X 0 By including at least one benzene ring, the melting point can be increased compared to the case where X 0 is an aliphatic hydrocarbon group (e.g., a normal alkyl chain), so the color retention property during storage at high temperature and high humidity (hereinafter referred to as "high temperature and high humidity storage property") can be improved. From the viewpoint of improving the high temperature and high humidity storage property and heat resistance, it is preferable that X 0 contains at least two benzene rings. The high temperature and high humidity storage property is, for example, the storage property in an environment of 80°C and 60% RH. When the heat resistance is improved, the resistance of the recording medium 20 to severe processes (e.g., heat pressing or integral molding using a molten resin, etc.) is improved. When X 0 contains at least two benzene rings, the at least two benzene rings may be condensed. For example, naphthalene or anthracene, etc. may be used.

[0110] Z 01 , Z 02Because each of these groups is independently a hydrogen bonding group, the color developers tend to remain somewhat cohesive through hydrogen bonding, thereby improving the stability of the color developers within the color development layers 24, 27, and 30. In this specification, a hydrogen bonding group means a functional group that contains an atom capable of forming hydrogen bonds with other functional groups or atoms present in other compounds.

[0111] The color developer preferably contains a compound represented by the following formula (4). [ka] (However, in equation (4), X 1 Y is a divalent group containing at least one benzene ring. 11 , Y 12 , Y 13 , Y 14 Each of them is an independent, unequal basis. Z 11 , Z 12 Each of these is an independent hydrogen bonding group.

[0112] X 1 X contains at least one benzene ring. 1 Since the melting point can be increased compared to when it is an aliphatic hydrocarbon group (e.g., a normal alkyl chain), the high-temperature, high-humidity storage characteristics can be improved. From the viewpoint of improving high-temperature, high-humidity storage characteristics and heat resistance, X 1 However, it is preferable that it contains at least two benzene rings. 1 If it contains at least two benzene rings, at least two benzene rings may be fused together. For example, it may be naphthalene or anthracene, etc.

[0113] Z 11 , Z 12 Because each of these groups is independently a hydrogen bonding group, the color developers tend to remain somewhat cohesive through hydrogen bonding, thereby improving the stability of the color developers within the color development layers 24, 27, and 30.

[0114] When formulas (3) and (4) contain hydrocarbon groups, these hydrocarbon groups are a general term for groups composed of carbon (C) and hydrogen (H), and may be saturated hydrocarbon groups or unsaturated hydrocarbon groups. Saturated hydrocarbon groups are aliphatic hydrocarbon groups that do not have multiple carbon-carbon bonds, and unsaturated hydrocarbon groups are aliphatic hydrocarbon groups that have multiple carbon-carbon bonds (carbon-carbon double bonds or carbon-carbon triple bonds).

[0115] If formulas (3) and (4) contain a hydrocarbon group, the hydrocarbon group may be in the form of a chain or may contain one or more rings. The chain may be linear or branched, having one or more side chains, etc.

[0116] (X containing one benzene ring) 0 , X 1 ) X in equation (3) 0 and X in equation (4) 1 This is, for example, a divalent group containing one benzene ring. This divalent group can be represented, for example, by the following formula (5). [ka] (However, in equation (5), X 21 It can be there or not, X 21 If X 21 X is a divalent group. 22 It can be there or not, X 22 If X 22 R is a divalent group. 21 is a single-valued base. n21 is an integer from 0 to 4. If n21 is an integer from 2 to 4, then R 21 These elements may be identical or different. (* indicates a connection point.)

[0117] In equation (5), X relative to the benzene ring 21 and X 22 The bonding position of X is not limited. That is, X relative to the benzene ring. 21 and X 22The bond position may be the ortho, meta, or para position.

[0118] The above divalent group containing one benzene ring is preferably represented by the following formula (6) from the viewpoint of improving high-temperature and high-humidity storage characteristics. [ka] (However, in equation (6), R 22 is a single-valued base. n²² is an integer from 0 to 4. If n²² is an integer from 2 to 4, then R 22 These elements may be identical or different. (* indicates a connection point.)

[0119] X in equation (3) 0 If is a divalent group containing one benzene ring, then in formula (6), Z relative to the benzene ring 01 and Z 02 The bonding position is not limited. That is, Z relative to the benzene ring. 01 and Z 02 The bond position may be the ortho, meta, or para position.

[0120] X in equation (4) 1 If is a divalent group containing one benzene ring, then in formula (6), Z relative to the benzene ring 11 and Z 12 The bonding position is not limited. That is, Z relative to the benzene ring. 11 and Z 12 The bond position may be the ortho, meta, or para position.

[0121] (X 21 , X 22 ) X in equation (5) 21 , X 22Each of these groups can be independently a divalent group and is not particularly limited, but examples include hydrocarbon groups which may have substituents. The hydrocarbon groups are preferably in a chain form. When the hydrocarbon groups are in a chain form, the melting point of the color developer can be reduced, so that the color developer dissolves upon irradiation with laser light and the color-developing compound becomes easier to color. From the viewpoint of reducing the melting point of the color developer, among the chain-like hydrocarbon groups, a n-alkyl chain is particularly preferred.

[0122] The number of carbon atoms in the hydrocarbon group, which may have substituents, is, for example, 1 to 15, 1 to 13, 1 to 12, 1 to 10, 1 to 6, or 1 to 3.

[0123] X in equation (5) 21 , X 22 When the normal alkyl group is a normal alkyl group, the number of carbon atoms in the normal alkyl group is preferably 8 or less, more preferably 6 or less, even more preferably 5 or less, and particularly preferably 3 or less, from the viewpoint of high-temperature storage stability. When the number of carbon atoms in the normal alkyl group is 8 or less, the length of the normal alkyl group is short, so thermal disturbance is less likely to occur in the color developer during high-temperature storage, and the site that interacted with the color-developing compound such as leuco dye during color development is less likely to detach. Therefore, the color-developing compound such as leuco dye is less likely to lose its color during high-temperature storage, thus improving high-temperature storage stability.

[0124] Examples of substituents that a hydrocarbon group may have include halogen groups (e.g., fluorine groups) or alkyl groups having halogen groups (e.g., fluorine groups). A hydrocarbon group that may have substituents may be one in which some of the carbon atoms of the hydrocarbon group (e.g., some of the carbon atoms in the main chain of the hydrocarbon group) are substituted with an element such as oxygen.

[0125] (R 21 ) R in equation (5) 21 This can be any monovalent group and is not particularly limited, but examples include a halogen group or a hydrocarbon group which may have substituents.

[0126] Halogen groups include, for example, fluorine (-F), chlorine (-Cl), bromine (-Br), or iodine (-I).

[0127] The number of carbon atoms in the hydrocarbon group, which may have substituents, is, for example, 1 to 15, 1 to 13, 1 to 12, 1 to 10, 1 to 6, or 1 to 3.

[0128] Examples of substituents that a hydrocarbon group may have include halogen groups (e.g., fluorine groups) or alkyl groups having halogen groups (e.g., fluorine groups). A hydrocarbon group that may have substituents may be one in which some of the carbon atoms of the hydrocarbon group (e.g., some of the carbon atoms in the main chain of the hydrocarbon group) are substituted with an element such as oxygen.

[0129] (R 22 ) R in equation (6) 22 R can be any monovalent group and is not particularly limited, but examples include a halogen group or a hydrocarbon group which may have a substituent. The halogen group and the hydrocarbon group which may have a substituent are R in formula (3) above, respectively. 21 It is similar to that.

[0130] (X containing two benzene rings) 0 , X 1 ) X in equation (3) 0 and X in equation (4) 1 This is, for example, a divalent group containing two benzene rings. This divalent group can be represented, for example, by the following formula (7). [ka] (However, in equation (7), X 31 It can be there or not, X 31 If X 31 X is a divalent group. 32 It can be there or not, X 32 If X 32 X is a divalent group.33 may or may not exist, X 33 if exists, X 33 is a divalent group. R 31 , R 32 are each independently a monovalent group. n31 and n32 are each independently an integer from 0 to 4. When n31 is an integer from 2 to 4, R 31 may be the same as or different from each other. When n32 is an integer from 2 to 4, R 32 may be the same as or different from each other. The * mark represents a bonding site.)

[0131] In formula (7), the bonding positions of X 31 and X 32 to the benzene ring are not limited. That is, the bonding positions of X 31 and X 32 to the benzene ring may be any of the ortho, meta, and para positions. Similarly, in formula (7), the bonding positions of X 32 and X 33 to the benzene ring are not limited. That is, the bonding positions of X 32 and X 33 to the benzene ring may be any of the ortho, meta, and para positions.

[0132] The divalent group containing two benzene rings is preferably represented by the following formula (8) from the viewpoint of improving the high-temperature and high-humidity storage characteristics.

Chemical formula

[0133] X in equation (3) 0 If is a divalent group containing two benzene rings, then in formula (8), Z relative to the benzene rings 01 and X 34 The bonding position is not limited. That is, Z relative to the benzene ring. 01 and X 34 The bond position may be the ortho, meta, or para position. Similarly, in formula (8), Z relative to the benzene ring 02 and X 34 The bonding position is not limited. That is, Z relative to the benzene ring. 02 and X 34 The bond position may be the ortho, meta, or para position.

[0134] X in equation (4) 1 If is a divalent group containing two benzene rings, then in formula (8), Z relative to the benzene rings 11 and X 34 The bonding position is not limited. That is, Z relative to the benzene ring. 11 and X 34 The bond position may be the ortho, meta, or para position. Similarly, in formula (8), Z relative to the benzene ring 12 and X 34 The bonding position is not limited. That is, Z relative to the benzene ring. 12 and X 34 The bond position may be the ortho, meta, or para position.

[0135] (X 31 , X 32 , X 33 ) X in equation (7) 31 , X 32 , X 33 Each of these can be a divalent group, and is not particularly limited, but an example would be a hydrocarbon group which may have substituents. The hydrocarbon group is X in formula (5) above.21 , X 22 It is similar to that.

[0136] (X 34 ) X in equation (8) 34 X in formula (5) above can be any divalent group and is not particularly limited, but an example is a hydrocarbon group which may have substituents. 21 , X 22 It is similar to that.

[0137] (R 31 , R 32 ) R in equation (7) 31 , R 32 R can be any monovalent group and is not particularly limited, but examples include a halogen group or a hydrocarbon group which may have substituents. The halogen group and the hydrocarbon group which may have substituents are R in formula (5) above, respectively. 21 It is similar to that.

[0138] (R 33 , R 34 ) R in equation (8) 33 , R 34 R can be any monovalent group and is not particularly limited, but examples include a halogen group or a hydrocarbon group which may have substituents. The halogen group and the hydrocarbon group which may have substituents are R in formula (5) above, respectively. 21 It is similar to that.

[0139] (Y 01 , Y 02 ) Y in equation (3) 01 , Y 02 Each of these is independently, for example, a hydrogen group (-H), a hydroxyl group (-OH), a halogen group (-X), a carboxyl group (-COOH), an ester group (-COOR), or a hydrocarbon group which may have a substituent.

[0140] Halogen groups include, for example, fluorine (-F), chlorine (-Cl), bromine (-Br), or iodine (-I).

[0141] The number of carbon atoms in the hydrocarbon group, which may have substituents, is, for example, 1 to 15, 1 to 13, 1 to 12, 1 to 10, 1 to 6, or 1 to 3.

[0142] Examples of substituents that a hydrocarbon group may have include halogen groups (e.g., fluorine groups) or alkyl groups having halogen groups (e.g., fluorine groups). A hydrocarbon group that may have substituents may be one in which some of the carbon atoms of the hydrocarbon group (e.g., some of the carbon atoms in the main chain of the hydrocarbon group) are substituted with an element such as oxygen.

[0143] In equation (3), (Y 01 ) n01 one of the following, and / or (Y 02 ) n02 It is preferable that one of them is a hydroxyl group (-OH). (Y 01 ) n01 one of the following, and / or (Y 02 ) n02 One of these groups is a hydroxyl group (-OH), which improves label quality and lightfastness.

[0144] (Y 11 , Y 12 , Y 13 , Y 14 ) In equation (4), Y relative to the benzene ring 11 and Y 12 The bonding position is not limited. That is, Y relative to the benzene ring. 11 and Y 12 The bond position of can be any of the ortho, meta, or para positions. Similarly, in formula (4), Y relative to the benzene ring 13 and Y 14 The bonding position is not limited. That is, Y relative to the benzene ring. 13 and Y 14The bond position may be any of the ortho, meta, or para positions. In formula (4), Y for one of the benzenes 11 and Y 12 The bond position of and Y relative to the other benzene 13 and Y 14 The bonding position may be the same as or different from that of the two elements.

[0145] Y in equation (4) 11 , Y 12 , Y 13 , Y 14 Each of these is independently, for example, a hydrogen group (-H), a hydroxyl group (-OH), a halogen group, a carboxyl group (-COOH), an ester group (-COOR), or a hydrocarbon group which may have a substituent. The halogen group and the hydrocarbon group which may have a substituent are Y in formula (3) above, respectively. 01 , Y 02 It is similar to that.

[0146] In equation (4), Y 11 and / or Y 13 It is preferable that it is a hydroxyl group (-OH). 11 and / or Y 13 The presence of a hydroxyl group (-OH) improves both label quality and lightfastness.

[0147] (Z 01 , Z 02 ) Z in equation (3) 01 , Z 02 These are, independently of each other, for example, urea bonds (-NHCONH-), amide bonds (-NHCO-, -OCHN-), or hydrazide bonds (-NHCOCONH-). From the viewpoint of improving high temperature and high humidity storage characteristics, Z 01 , Z 02 It is preferable that it is a urea bond. 01 If it is an amide bond, the nitrogen contained in the amide bond may be bonded to benzene, or the carbon contained in the amide bond may be bonded to benzene. 02If the bond is an amide bond, the nitrogen contained in the amide bond may be bonded to benzene, or the carbon contained in the amide bond may be bonded to benzene.

[0148] (Z 11 , Z 12 ) Z in equation (4) 11 , Z 12 These are, independently of each other, for example, urea bonds (-NHCONH-), amide bonds (-NHCO-, -OCHN-), or hydrazide bonds (-NHCOCONH-). From the viewpoint of improving high temperature and high humidity storage characteristics, Z 11 , Z 12 It is preferable that it is a urea bond. 11 If it is an amide bond, the nitrogen contained in the amide bond may be bonded to benzene, or the carbon contained in the amide bond may be bonded to benzene. 12 If the bond is an amide bond, the nitrogen contained in the amide bond may be bonded to benzene, or the carbon contained in the amide bond may be bonded to benzene.

[0149] (Specific examples of color developers) X in equation (3) 0 and X in equation (4) 1 A color developer containing one benzene ring specifically includes, for example, at least one selected from the group consisting of compounds represented by the following formulas (9-1) to (9-6). [ka]

[0150] X in equation (3) 0 and X in equation (4) 1 A color developer containing two benzene rings specifically includes, for example, at least one selected from the group consisting of compounds represented by the following formulas (10-1) to (10-8). [ka]

[0151] (Example 7) In the first and second embodiments, examples were described in which the laminates 10 and 40 include a recording medium 20 (see Figure 3). However, the laminates 10 and 40 may also include a recording medium 20A shown in Figure 15 instead of the recording medium 20.

[0152] The recording medium 20A comprises a base material 21, an adhesive layer 22, a color development layer 24, an intermediate layer 35A, a color development layer 27, an intermediate layer 35B, a color development layer 30, an intermediate layer 35C, and a protective layer 36 in this order. More specifically, the recording medium 20A comprises a base material 21, an adhesive layer 22, a color development layer 24, a diffusion suppression layer 26, an adhesive layer 25, a color development layer 27, a diffusion suppression layer 29, an adhesive layer 28, a color development layer 30, a diffusion suppression layer 34, an adhesive layer 33, and a protective layer 36 in this order.

[0153] Intermediate layer 35A is the same as intermediate layer 32B of the recording medium 20, except that the diffusion suppression layer 26 is adjacent to the color development layer 24 and the adhesive layer 25 is adjacent to the color development layer 27. Intermediate layer 35B is the same as intermediate layer 32C of the recording medium 20, except that the diffusion suppression layer 29 is adjacent to the color development layer 27 and the adhesive layer 28 is adjacent to the color development layer 30. Intermediate layer 35C is the same as intermediate layer 32D of the recording medium 20, except that the diffusion suppression layer 34 is adjacent to the color development layer 30 and the adhesive layer 33 is adjacent to the protective layer 36.

[0154] The protective layer 36 comprises, in order, an ultraviolet-curable resin layer 36A, a UV-cut layer 36B, an adhesive layer 36C, and a substrate 36D on one main surface of the intermediate layer 35C. The ultraviolet-curable resin layer 36A can protect the surface of the recording medium 20A. The ultraviolet-curable resin layer 36A may also function as a diffusion-inhibiting layer and / or a diffusion-preventing layer. The UV-cut layer 36B can cut ultraviolet rays incident on the color-developing layers 24, 27, and 30.

[0155] The adhesive layer 36C can bond the UV-cut layer 36B and the substrate 36D. Examples of materials for the adhesive layer 36C include those similar to those used for adhesive layers 22, 25, 28, and 33. The substrate 36D can support the UV-curable resin layer 36A, the UV-cut layer 36B, and the adhesive layer 36C. The substrate 36D can protect the surface of the recording medium 20A. Examples of materials for the substrate 36D include those similar to those used for substrate 11.

[0156] From the viewpoint of improving adhesion, it is preferable that the matrix polymer contained in the color-developing layer 24 and the resin material contained in the diffusion-suppressing layer 26 contain the same type of resin material. From the viewpoint of improving adhesion, it is preferable that the matrix polymer contained in the color-developing layer 27 and the resin material contained in the diffusion-suppressing layer 29 contain the same type of resin material. From the viewpoint of improving adhesion, it is preferable that the matrix polymer contained in the color-developing layer 30 and the resin material contained in the diffusion-suppressing layer 34 contain the same type of resin material.

[0157] From the viewpoint of improving adhesion, it is preferable that the matrix polymer contained in the color-developing layer 24 and the resin material contained in the diffusion-suppressing layer 26 contain amorphous resin. From the viewpoint of improving adhesion, it is preferable that the matrix polymer contained in the color-developing layer 27 and the resin material contained in the diffusion-suppressing layer 29 contain amorphous resin. From the viewpoint of improving adhesion, it is preferable that the matrix polymer contained in the color-developing layer 30 and the resin material contained in the diffusion-suppressing layer 34 contain amorphous resin.

[0158] From the viewpoint of improving adhesion, the matrix polymer contained in the color-developing layer 24 and the resin material contained in the diffusion-suppressing layer 26 preferably contain a crystalline resin. From the viewpoint of improving adhesion, the matrix polymer contained in the color-developing layer 27 and the resin material contained in the diffusion-suppressing layer 29 preferably contain a crystalline resin. From the viewpoint of improving adhesion, the matrix polymer contained in the color-developing layer 30 and the resin material contained in the diffusion-suppressing layer 34 preferably contain a crystalline resin.

[0159] (Variation 8) The laminate 10, 40 may include a recording medium 20B shown in FIG. 16 instead of the recording medium 20 (see FIG. 3). The recording medium 20B is different from the recording medium 20 in that it includes a protective layer 36 instead of the protective layer 31. The protective layer 36 is as described in Modification Example 7. As shown in FIG. 28, the recording medium 20B may further include an adhesive layer 81 between the coloring layer 30 and the protective layer 36. The adhesive layer 81 bonds the coloring layer 30 and the protective layer 36 together. By providing the adhesive layer 81 between the coloring layer 30 and the protective layer 36, the adhesion between the coloring layer 30 and the protective layer 36 can be improved. The adhesive layer 81 may be an optical adhesive sheet such as an OCA (Optical Clear Adhesive). Examples of the adhesive included in the adhesive layer 81 can be the same materials as the adhesive layers 22, 25, 28, 33. In FIGS. 16 and 28, an example in which the recording medium 20B includes a base material 21 and an intermediate layer 32A is shown, but the recording medium 20B may not include the base material 21 and the intermediate layer 32A.

[0160] (Modification Example 9) The laminate 10, 40 may include a recording medium 20C shown in FIG. 17 instead of the recording medium 20 (see FIG. 3). The recording medium 20C is different from the recording medium 20A in that it includes intermediate layers 37A, 37B, 37C instead of the intermediate layers 35A, 35B, 35C. The recording medium 20C may not include the base material 21 and the adhesive layer 22.

[0161] The intermediate layer 37A comprises a diffusion-suppressing layer 26A and an adhesive layer 25 in order on one main surface of the color-developing layer 24. The diffusion-suppressing layer 26A comprises a resin layer 26A1 and an ultraviolet-curable resin layer 26A2 in order on one main surface of the color-developing layer 24. The resin layer 26A1 is provided between the color-developing layer 24 and the ultraviolet-curable resin layer 26A2. The resin layer 26A1 can improve the adhesion between the color-developing layer 24 and the ultraviolet-curable resin layer 26A2. The resin layer 26A1 contains the same type of resin material as the matrix polymer contained in the color-developing layer 24. For example, if the color-developing layer 24 contains a polycarbonate-based resin as the matrix polymer, then the resin layer 26A1 contains a polycarbonate-based resin. The ultraviolet-curable resin layer 26A2 is the same as the ultraviolet-curable resin layer of the diffusion-suppressing layer 26 in the first embodiment.

[0162] The intermediate layer 37B comprises a diffusion-suppressing layer 29A and an adhesive layer 28 in order on one main surface of the color-developing layer 27. The diffusion-suppressing layer 29A comprises a resin layer 29A1 and an ultraviolet-curable resin layer 29A2 in order on one main surface of the color-developing layer 27. The resin layer 29A1 is provided between the color-developing layer 27 and the ultraviolet-curable resin layer 29A2. The resin layer 29A1 can improve the adhesion between the color-developing layer 27 and the ultraviolet-curable resin layer 29A2. The resin layer 29A1 contains the same type of resin material as the matrix polymer contained in the color-developing layer 27. For example, if the color-developing layer 27 contains a polycarbonate-based resin as the matrix polymer, then the resin layer 29A1 contains a polycarbonate-based resin. The ultraviolet-curable resin layer 29A2 is the same as the ultraviolet-curable resin layer of the diffusion-suppressing layer 29 in the first embodiment.

[0163] The intermediate layer 37C includes a diffusion suppression layer 34A and an adhesive layer 33 on one main surface of the color developing layer 30 in this order. The diffusion suppression layer 34A includes a resin layer 34A1 and an ultraviolet curable resin layer 34A2 on one main surface of the color developing layer 30 in this order. The resin layer 34A1 is provided between the color developing layer 30 and the ultraviolet curable resin layer 34A2. The resin layer 34A1 can improve the adhesion between the color developing layer 30 and the ultraviolet curable resin layer 34A2. The resin layer 34A1 includes the same type of resin material as the matrix polymer contained in the color developing layer 30. For example, when the color developing layer 30 includes a polycarbonate resin as the matrix polymer, the resin layer 34A1 includes a polycarbonate resin. The ultraviolet curable resin layer 34A2 is the same as the ultraviolet curable resin layer of the diffusion suppression layer 34 in the first embodiment.

[0164] The reason why the resin layer 26A1 is provided between the color developing layer 24 and the ultraviolet curable resin layer 26A2 is as follows. When the color developing layer 24 includes a particulate developer, the particulate developer is distributed on the surface of the color developing layer 24. Therefore, when the color developing layer 24 and the ultraviolet curable resin layer 26A2 are adjacent to each other, there is a possibility that the adhesion decreases. As described above, when the resin layer 26A1 is adjacent to the color developing layer 24 and the resin layer 26A1 includes the same type of resin material as the matrix polymer contained in the color developing layer 24, the adhesion at the interface other than the portion where the developer is distributed can be improved. Therefore, it is possible to compensate for the decrease in adhesion due to the particulate developer.

[0165] The reason why the resin layer 29A1 is provided between the color developing layer 27 and the ultraviolet curable resin layer 29A2, and the reason why the resin layer 34A1 is provided between the color developing layer 30 and the ultraviolet curable resin layer 34A2 are the same as the reason why the resin layer 26A1 is provided between the color developing layer 24 and the ultraviolet curable resin layer 26A2.

[0166] (Modification 10) The laminates 10 and 40 may have a recording medium 20D shown in Figure 18 instead of the recording medium 20 (see Figure 3) in the laminate 10. The recording medium 20D differs from the recording medium 20A in that it has intermediate layers 38A, 38B, and 38C instead of intermediate layers 35A, 35B, and 35C.

[0167] The intermediate layer 38A comprises a diffusion suppression layer 26B and an adhesive layer 25 sequentially on one main surface of the color development layer 24. The diffusion suppression layer 26B comprises an adhesive layer 26B1 and an ultraviolet-curable resin layer 26B2 sequentially on one main surface of the color development layer 24. The adhesive layer 26B1 is provided between the color development layer 24 and the ultraviolet-curable resin layer 26B2. The adhesive layer 26B1 can bond the color development layer 24 and the ultraviolet-curable resin layer 26B2. By providing the adhesive layer 26B1 between the color development layer 24 and the ultraviolet-curable resin layer 26B2, the reduction in adhesion due to the color developer contained in the color development layer 24 can be compensated for. Examples of materials for the adhesive layer 26B1 include the same materials as those used for adhesive layers 22, 25, 28, and 33.

[0168] The intermediate layer 38B comprises a diffusion suppression layer 29B and an adhesive layer 28 sequentially on one main surface of the color development layer 27. The diffusion suppression layer 29B comprises an adhesive layer 29B1 and an ultraviolet-curable resin layer 29B2 sequentially on one main surface of the color development layer 27. The adhesive layer 29B1 is provided between the color development layer 27 and the ultraviolet-curable resin layer 29B2. The adhesive layer 29B1 can bond the color development layer 27 and the ultraviolet-curable resin layer 29B2. By providing the adhesive layer 29B1 between the color development layer 27 and the ultraviolet-curable resin layer 29B2, the reduction in adhesion due to the color developer contained in the color development layer 27 can be compensated for. Examples of materials for the adhesive layer 29B1 include materials similar to those used for adhesive layers 22, 25, 28, and 33.

[0169] The intermediate layer 38C comprises a diffusion suppression layer 34B and an adhesive layer 33 sequentially on one main surface of the color development layer 30. The diffusion suppression layer 34B comprises an adhesive layer 34B1 and an ultraviolet-curable resin layer 34B2 sequentially on one main surface of the color development layer 30. The adhesive layer 34B1 is provided between the color development layer 30 and the ultraviolet-curable resin layer 34B2. The adhesive layer 34B1 can bond the color development layer 30 and the ultraviolet-curable resin layer 34B2. By providing the adhesive layer 34B1 between the color development layer 30 and the ultraviolet-curable resin layer 34B2, the reduction in adhesion due to the color developer contained in the color development layer 30 can be compensated for. Examples of materials for the adhesive layer 34B1 include the same materials as those for the adhesive layers 22, 25, 28, and 33.

[0170] (Variation 11) The laminates 10 and 40 may include a recording medium 20E shown in Figure 19 instead of the recording medium 20 (see Figure 3). The recording medium 20E differs from the recording medium 20A in that it includes intermediate layers 39A, 39B, and 39C instead of intermediate layers 35A, 35B, and 35C. The recording medium 20E may not include a base material 21 and an adhesive layer 22.

[0171] The intermediate layers 39A and 39B are films. Preferably, the films are films that have undergone an easy-adhesion treatment. Examples of film materials include those similar to those used for the substrate 11. Examples of easy-adhesion treatments include priming, active energy ray irradiation, plasma treatment, corona treatment, vapor deposition, etching, and sandblasting. One or more of these can be selected. The priming treatment may be a priming treatment using a resin, silane coupling agent, or tetraalkoxysilane.

[0172] By providing an easily adhesive-treated film as an intermediate layer 39A between the color-developing layer 24 and the color-developing layer 27, the reduction in adhesion caused by the color developer contained in the color-developing layer 24 can be compensated for. By providing an easily adhesive-treated film as an intermediate layer 39B between the color-developing layer 27 and the color-developing layer 30, the reduction in adhesion caused by the color developer contained in the color-developing layer 27 can be compensated for.

[0173] The intermediate layer 39C is an adhesive layer. Examples of materials for the adhesive layer include those similar to those used for adhesive layers 22, 25, 28, and 33. By providing the adhesive layer as the intermediate layer 39C between the color-developing layer 30 and the protective layer 36, the reduction in adhesion caused by the color developer in the color-developing layer 30 can be compensated for.

[0174] (Example 12) The laminates 10 and 40 may have a recording medium 20F shown in Figure 20 instead of the recording medium 20 (see Figure 3). The recording medium 20F differs from the recording medium 20E in Modification 11 in that it has an intermediate layer 41B instead of an intermediate layer 39B.

[0175] The intermediate layer 41B comprises a resin layer 41B1 and a resin layer 41B2 in order on one main surface of the coloring layer 27. The resin layer 41B1 contains the same type of resin material as the matrix polymer contained in the coloring layer 27. For example, if the coloring layer 27 contains a polycarbonate-based resin as the matrix polymer, then the resin layer 41B1 contains a polycarbonate-based resin. The resin layer 41B2 is a film. The film is preferably a film that has been treated for easy adhesion. Examples of the film material include materials similar to those of the substrate 11.

[0176] As described above, the resin layer 41B1 is provided between the color development layer 27 and the resin layer 41B2, which compensates for the decrease in adhesion caused by the color developer contained in the color development layer 27.

[0177] (Example 13) The laminates 10 and 40 may have a recording medium 20G as shown in Figure 21 instead of the recording medium 20 (see Figure 3). The recording medium 20G differs from the recording medium 20E in Modification 11 in that it has an intermediate layer 38A instead of the intermediate layer 39A and also has a base material 42.

[0178] The intermediate layer 38A is as described in Modification Example 10 (see FIG. 18). The base material 42 is provided adjacent to the other surface of the color developing layer 24. The base material 42 is a film subjected to an easy adhesion treatment. As the material of the film, materials similar to those of the base material 11 can be exemplified.

[0179] (Modification Example 14) The laminate 10, 40 may include a recording medium 20H shown in FIG. 22 instead of the recording medium 20 (see FIG. 3). The recording medium 20H is different from the recording medium 20A in that it includes intermediate layers 42A, 42B instead of the intermediate layers 35A, 35B.

[0180] The intermediate layers 42A, 42B are adhesive layers. As the material of the adhesive layer, materials similar to those of the adhesive layers 22, 25, 28, 33 can be exemplified.

[0181] (Modification Example 15) In the first and second embodiments and their modification examples, examples in which the laminates 10, 40 are applied to cards have been described. However, the laminates 10, 40 may be applied to medical supplies, automotive parts, automobiles, toys, foods, cosmetics, ornaments, documents (e.g., passports, etc.), exterior members, or housings of electronic devices, etc. Specific examples of exterior members include, for example, interior or exterior finishes of building walls, etc., or exterior finishes of furniture such as desks. Specific examples of electronic devices include personal computers (hereinafter referred to as "PCs"), mobile devices, mobile phones (e.g., smartphones), tablet computers, display devices, imaging devices, audio devices, game devices, industrial instruments, medical devices, robots, or wearable terminals. Specific examples of wearable terminals include ornaments such as watches (wristwatches), bags, clothes, hats, glasses, or shoes.

[0182] Hereinafter, specific examples in which the laminates 10, 40 are applied to smartphones, notebook personal computers, and cosmetic containers will be described.

[0183] (Example of a smartphone) Figure 23A shows the front view of the smartphone 100, and Figure 23B shows the rear view of the smartphone 100 shown in Figure 23A. The smartphone 100 comprises, for example, a display unit 111 and a housing 112. A recording medium 20 is provided on the rear side of the housing 112. The housing 112 is made of a laminate. This laminate is the same as any of the laminates 10, 40 relating to the first and second embodiments and their variations, except that the base material has the shape of the smartphone 100 housing. This improves the anti-counterfeiting properties of the smartphone 100.

[0184] (Example of a laptop PC) Figure 24 shows the external configuration of the notebook PC 200. The notebook PC 200 comprises a computer body 210 and a display 220. The computer body 210 comprises a casing 211, a keyboard 212, a wheel / pad operation section 213, and click buttons 214 and 215. A recording medium 20 is provided in the casing 112. The casing 211 is made of a laminate. This laminate is the same as any of the laminates 10 and 40 relating to the first and second embodiments and their variations, except that the base material has the shape of the notebook PC 200 casing. This improves the anti-counterfeiting properties of the notebook PC 200.

[0185] (Example of a cosmetic container) Figure 25 shows the external appearance of the cosmetic container 300. This cosmetic container 300 comprises a storage compartment 311 and a lid 312 that covers the storage compartment 311. A recording medium 20 is provided on the lid 312. The lid 312 is made of a laminate. This laminate is the same as any of the laminates 10, 40 relating to the first and second embodiments and their variations, except that the base material has a shape corresponding to the lid 312. This improves the anti-counterfeiting properties of the cosmetic container 300.

[0186] (Example of a passport) Figure 26 shows the appearance of booklet 400. Booklet 400 is a passport. A passport is an example of a booklet-type identification document. Booklet 400 comprises a plurality of sheets 410. The plurality of sheets 410 are saddle-stitched. A recording medium 20, etc., is provided on at least one or both sides of a sheet 410. A photograph, etc., is drawn on the recording medium 20, etc. A sheet 410 is the same as any of the laminates 10, 40 according to the first and second embodiments and their variations. In this case, the base material 11 may be paper or the like.

[0187] Although embodiments and modifications of the present disclosure have been described in detail above, the present disclosure is not limited to the embodiments and modifications described above, and various modifications based on the technical idea of ​​the present disclosure are possible.

[0188] For example, the configurations, methods, processes, shapes, materials, and numerical values ​​listed in the above-described embodiments and modifications are merely examples, and different configurations, methods, processes, shapes, materials, and numerical values ​​may be used as needed. The configurations, methods, processes, shapes, materials, and numerical values ​​of the above-described embodiments and modifications can be combined with each other, as long as they do not deviate from the spirit of this disclosure.

[0189] In the numerical ranges described stepwise in the embodiments and modifications described above, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range. Unless otherwise specified, the materials exemplified in the embodiments and modifications described above can be used individually or in combination of two or more.

[0190] Furthermore, this disclosure may also adopt the following configuration. (1) Multiple color-developing layers, At least one diffusion suppression layer and Equipped with, The color-developing layer comprises an electron-donating color-developing compound, an electron-accepting color developer, and a matrix resin. The diffusion suppression layer is provided between adjacent color-developing layers. The diffusion-suppressing layer is a recording medium that can suppress the diffusion of the color-developing compound between adjacent color-developing layers when the recording medium is heated. (2) Further comprising at least one adhesive layer, The recording medium according to (1), wherein the adhesive layer is provided between the diffusion-suppressing layer and the color-developing layer. (3) The recording medium according to (1) or (2), wherein the average peel strength between each layer of the recording medium is 3.5 N / cm or more. (4) The recording medium according to (1) or (2), wherein the average peel strength between adjacent color-developing layers is less than 3.5 N / cm. (5) The recording medium according to any one of (1) to (4), wherein the matrix resin comprises a polycarbonate resin. (6) The recording medium according to any one of (1) to (5), wherein the heating temperature is 120°C or higher and 200°C or lower. (7) The recording medium according to any one of (1) to (6), wherein the heating temperature is 160°C or more and 200°C or less. (8) The recording medium according to any one of (1) to (7), wherein the diffusion suppression layer is a resin layer that does not have tackiness in a standard atmosphere with a temperature of 23±1°C and a relative humidity of 50±5%. (9) The recording medium according to any one of (1) to (8), wherein the Young's modulus of the diffusion suppression layer is 100 MPa or more. (10) The recording medium according to any one of (1) to (9), wherein the Young's modulus of the diffusion suppression layer is 2000 MPa or more. (11) The recording medium according to any one of (1) to (10), wherein the diffusion suppression layer is a resin layer having a pencil hardness of F or higher. (12) The diffusion suppression layer is a recording medium according to any one of (1) to (11), wherein the glass transition temperature is 130°C or higher. (13) The diffusion-suppressing layer comprises an amorphous resin, as described in any one of (1) to (12). (14) The diffusion-suppressing layer comprises a crystalline resin, as described in any one of (1) to (12). (15) The recording medium according to any one of (1) to (14), wherein the diffusion suppression layer comprises an ultraviolet curing resin. (16) A recording medium described in any one of items (1) to (15), Substrate and Overlay layer and Equipped with, The recording medium is a laminate provided between the substrate and the overlay layer. (17) The laminate according to (16), wherein the substrate and the recording medium are bonded together by fusion or thermal adhesive, and the recording medium and the overlay layer are bonded together by fusion or thermal adhesive.

[0191] <4 Reference Examples and Examples>

[0192] The present disclosure will be described in detail below with reference examples and embodiments, but the present disclosure is not limited to these reference examples and embodiments.

[0193] [Reference example 1-1] First, an adhesive layer was placed on the substrate, and then an overlay layer was placed on top of the adhesive layer to obtain a laminated structure. Next, this laminated structure was heated and pressurized at a temperature of 120°C to bond the substrate and the overlay layer via the adhesive layer. As a result, the desired laminate was obtained.

[0194] The following materials were used as the substrate, adhesive layer, and overlay layer. Overlay layer: 50 μm thick polycarbonate film (hereinafter referred to as "PC film"). Adhesive layer: 5 μm thick epoxy resin layer (thermosetting resin layer) Base material: PC film with a thickness of 25 μm

[0195] [Reference example 1-2] A laminate was obtained in the same manner as in Reference 1-1, except that the following materials were used as the base material and overlay layer. Overlay layer: 50 μm thick polyvinyl chloride film (hereinafter referred to as "PVC film"). Base material: 25μm thick PVC vinyl film

[0196] [Reference example 1-3] A laminate was obtained in the same manner as in Reference 1-1, except that the following materials were used as the base material and overlay layer. Overlay layer: 50 μm thick polyethylene terephthalate film (hereinafter referred to as "PET film"). Substrate: PET film with a thickness of 25 μm

[0197] [Reference example 1-4] A laminate was obtained in the same manner as in Reference 1-1, except that the following materials were used as the base material and overlay layer. Overlay layer: PET film with a thickness of 50 μm Base material: PC film with a thickness of 25 μm

[0198] [Reference examples 2-1, 2-2, 2-3, 2-4] A laminate was obtained in the same manner as in Reference Examples 1-1, 1-2, 1-3, and 1-4, except that the base material and overlay layer were sequentially laminated to obtain a laminated structure, and then this laminated structure was heated and pressurized at a temperature of 180°C to fuse the base material and overlay layer together.

[0199] [evaluation] The adhesion, environmental friendliness, and durability of the laminate obtained as described above were evaluated as follows.

[0200] (Adhesion) First, the average peel strength between the substrate and the overlay layer was measured. This average peel strength was measured using the method for measuring the average peel strength of a laminate described in the first embodiment. Next, the measured average peel strength was evaluated according to the following criteria. The evaluation results are shown in Table 1. ◎: The average peel strength between the substrate and the overlay layer is 5.0 N / cm or higher. ○: The average peel strength between the substrate and the overlay layer is 3.5 N / cm or higher. ×: The average peel strength between the substrate and the overlay layer is less than 3.5 N / cm.

[0201] (Environmental considerations) The environmental friendliness of the laminate was evaluated according to the following criteria. The evaluation results are shown in Table 1. ○: There is no possibility of harmful substances (especially dioxins) being generated when processing laminates with inadequate equipment. ×: Processing laminates with inadequate equipment may generate harmful substances (especially dioxins).

[0202] (durability) The durability of the laminate was evaluated according to the following criteria. The evaluation results are shown in Table 1. ○: No change in appearance (warping) occurs after heating. ×: If a change in appearance (warping) occurs after heating.

[0203] [Table 1]

[0204] The following can be seen from Table 1. By bonding the substrate and overlay layer using a thermosetting resin or fusion bonding, good adhesion can be obtained. From the viewpoint of improving adhesion, it is preferable to bond the substrate and the overlay layer by fusion. From an environmental perspective, it is preferable to use PC film or PET film as the base material and overlay layer. From the viewpoint of improving durability, it is preferable to use PC film or PVC film as the base material and overlay layer. From the viewpoint of environmental friendliness and improved durability, it is preferable to use PC film as the base material and overlay layer.

[0205] (Examples 1-3) First, a recording medium having the layer configuration shown in Figure 15 was fabricated by stacking the layers shown in Table 2. Next, a laminate was obtained in the same manner as in Reference Example 2-1, except that the recording medium was sandwiched between the substrate and the overlay layer. The interface of the recording medium was also bonded by a heating and pressing process after stacking the substrate, intermediate layer, and overlay layer.

[0206] (Example 4) A laminate was obtained in the same manner as in Example 1, except that a recording medium having the layer configuration shown in Figure 22 was fabricated by stacking each layer shown in Table 3.

[0207] (Example 5) A laminate was obtained in the same manner as in Example 1, except that a recording medium having the layer configuration shown in Figure 17 was fabricated by stacking each layer shown in Table 3.

[0208] (Example 6) A laminate was obtained in the same manner as in Example 1, except that a recording medium having the layer configuration shown in Figure 18 was fabricated by stacking each layer shown in Table 3.

[0209] (Example 7) A laminate was obtained in the same manner as in Example 1, except that a recording medium having the layer configuration shown in Figure 19 was fabricated by stacking each layer shown in Table 4.

[0210] (Example 8) A laminate was obtained in the same manner as in Example 1, except that a recording medium having the layer configuration shown in Figure 20 was fabricated by stacking each layer shown in Table 4.

[0211] (Example 9) A laminate was obtained in the same manner as in Example 1, except that a recording medium having the layer configuration shown in Figure 19 was fabricated by stacking each layer shown in Table 4.

[0212] (Example 10) A laminate was obtained in the same manner as in Example 1, except that a recording medium having the layer configuration shown in Figure 21 was fabricated by stacking each layer shown in Table 4.

[0213] [evaluation] The adhesion and durability of the laminate obtained as described above were evaluated as follows.

[0214] (Adhesion) First, the average peel strength between each layer of the laminate was measured. This average peel strength was measured using the method for measuring the average peel strength of a laminate described in the first embodiment. Next, the measured average peel strength was evaluated according to the following criteria. The lowest average peel strength between each layer of the laminate is shown in Tables 2, 3, and 4. The location of the interface with the lowest average peel strength is also shown in Tables 2, 3, and 4. ○: The average peel strength between each layer is 3.5 N / cm or higher. ×: At least one of the average peel strengths between each layer is less than 3.5 N / cm.

[0215] (Anti-counterfeiting) The anti-counterfeiting properties of the laminate were evaluated according to the following criteria. ○: Satisfies at least one of the following conditions (1) and (2). ×: Does not meet either condition (1) or condition (2) below. Condition (1): The average peel strength between each layer of the laminate is 3.5 N / cm or higher. Condition (2): The interface with the lowest average peel strength is located between the color-developing layers.

[0216] (Maximum color intensity OD) First, the maximum color OD of the laminate was measured using the eXact spectrophotometer (manufactured by X-Rite). Next, the color development was evaluated according to the following criteria. The evaluation results are shown in Tables 2, 3, and 4. ○: The maximum color rendering OD is 1.0 or higher. The standard is an OD value of 1.0, which is the value at which a person can be recognized when drawing a person. ×: The maximum color OD is less than 1.0. When the OD value is less than 1.0, it becomes difficult to recognize people when drawing them.

[0217] (Color gamut retention rate after heating) First, using the eXact spectrophotometer and densitometer, the colored and uncolored areas of the recording medium before and after heating were measured. * b * The color gamut was measured and calculated. The color gamut retention rate after heating was determined from the color gamut before and after heating. Next, the color gamut retention rate after heating was evaluated according to the following criteria. The evaluation results are shown in Tables 2, 3, and 4. ○: The color gamut retention rate after heating is 80% or higher. ×: The color gamut retention rate after heating is less than 80%. Furthermore, a color gamut retention rate of 80% or higher ensures sufficient color representation when depicting people.

[0218] [Table 2]

[0219] [Table 3]

[0220] [Table 4]

[0221] Details of each component listed in Tables 2, 3, and 4 are as follows. PC: PC film PET: PET film Easy-adhesion treated PET: PET film treated with an easy-adhesion process (manufactured by Mitsubishi Chemical Corporation, Diafoil® registered trademark) OCA: Optical Clear Adhesive UV Resin: UV-curable resin layer (acrylic resin layer for hard coating) Matrix polymer layer: A resin layer (specifically, a polycarbonate-based resin layer) composed of the same type of polymer as the matrix polymer contained in the adjacent coloring layer. Coloring layer Y1: A coloring layer containing a yellow leuco dye, a color developer, and a polycarbonate resin, wherein the polycarbonate resin content in the coloring layer is 58% by mass. Coloring layer Y2: A coloring layer containing a yellow leuco dye, a color developer, and a polycarbonate resin, wherein the polycarbonate resin content in the coloring layer is 68% by mass. Coloring layer C1: A coloring layer containing a cyan-coloring leuco dye, a color developer, and a polycarbonate resin, wherein the polycarbonate resin content in the coloring layer is 65% by mass. Coloring layer C2: A coloring layer containing a cyan-coloring leuco dye, a color developer, and a polycarbonate resin, wherein the polycarbonate resin content in the coloring layer is 75% by mass. Coloring layer M1: A coloring layer containing a magenta-colored leuco dye, a color developer, and a polycarbonate-based resin, wherein the polycarbonate-based resin content in the coloring layer is 58% by mass. Coloring layer M2: A coloring layer containing a magenta-colored leuco dye, a color developer, and a polycarbonate-based resin, wherein the polycarbonate-based resin content in the coloring layer is 68% by mass.

[0222] From Tables 2, 3, and 4, the following can be seen. If the intermediate layer between the color-developing layers is composed of a matrix polymer layer, an UV-curable resin layer, and an adhesive layer, the adhesion between the color-developing layer and the intermediate layer can be improved (see evaluation results in Example 5). If the intermediate layer between the color-developing layers is composed of an adhesive layer, an UV-curable resin layer, and another adhesive layer, the adhesion between the color-developing layer and the intermediate layer can be improved (see evaluation results in Examples 6 and 10). When the intermediate layer between the color-developing layers is composed of a matrix polymer layer and a film, the adhesion between the color-developing layer and the intermediate layer can be improved (see evaluation results in Example 8). If the intermediate layer between the color-developing layers is made of an easily adhesive treated film, the adhesion between the color-developing layer and the intermediate layer can be improved (see evaluation results in Examples 9 and 10).

[0223] (Reference examples 3-1~3-5) Samples were obtained by laminating a 25 μm thick PC film, a 5 μm thick polycarbonate resin-containing layer, and a 25 μm thick PC film, then heating and pressurizing them at 180°C to fuse them together. The polycarbonate resin-containing layer used had the composition shown in Table 5.

[0224] (Adhesion) First, the average peel strength between each layer of the sample was measured. This average peel strength was measured using the method for measuring the average peel strength of a laminate described in the first embodiment. Next, the measured average peel strength was evaluated according to the following criteria. ○: The average peel strength between each layer is 3.5 N / cm or higher. ×: At least one of the average peel strengths between each layer is less than 3.5 N / cm. The evaluation results are shown in Table 5 and Figure 27. Note that the average peel strength listed in Table 5 represents the average peel strength between the polycarbonate resin-containing layer and the PC film.

[0225] [Table 5]

[0226] Details of each component and material listed in Table 5 are as follows: Matrix polymer: Polycarbonate-based resin Chromogen: Compound represented by formula (3)

[0227] Table 5 and Figure 27 show that when the ratio of the developer to the total amount of the developer and matrix polymer is less than 18% by mass, the peel strength can be increased to 3.5 N / cm or higher. [Explanation of symbols]

[0228] 10, 40 laminated 11, 21, 51 Base material 12, 13 Adhesive layer 13A, 16A Accommodation Section 14 Overlay Layer 15 Middle Class 15A IC chip 16 Fine printing layer 17 Barrier layer 20, 20A, 20B, 20C, 20D, 20E, 20F, 20G, 20H, 50 recording media 20HL hole 22, 25, 28, 33 Adhesive layer 23, 26, 29, 34, 26A, 29A, 34A, 26B, 29B, 34B Diffusion suppression layer 24, 27, 30 Color-developing layers 26A1, 29A1, 34A1 resin layer 26A2, 29A2, 34A2, 26B2, 29B2, 34B2 UV curable resin layer 26B1, 29B1, 34B1 Adhesive layer 31, 36 protective layer 32A, 32B, 32C, 35A, 35B, 35C, 37A, 37B, 37C, 38A, 38B, 38C Intermediate layer 36A UV curable resin layer 36B UV-cut layer 36C Adhesive layer 36D base material 60 test specimens 60A, 60B Adherent 61 Tensile members 62 Clamping device 71 Test bench 72 Jigs 73A, 73B Movable Roll 100 Smartphones 200 Notebook Personal Computers 300 cosmetic containers 400 booklets

Claims

1. Multiple color-developing layers, At least one diffusion suppression layer and Equipped with, The color-developing layer comprises an electron-donating color-developing compound, an electron-accepting color developer, and a matrix resin. The diffusion suppression layer is provided between adjacent color-developing layers. The diffusion-suppressing layer comprises an ultraviolet-curable resin or a thermosetting resin. At least one adhesive layer is provided between the diffusion-suppressing layer and one of the adjacent color-developing layers. The diffusion-suppressing layer is a recording medium that can suppress the diffusion of the color-developing compound between adjacent color-developing layers when the recording medium is heated.

2. The recording medium according to claim 1, wherein the average peel strength between each layer of the recording medium is 3.5 N / cm or more.

3. The recording medium according to claim 1, wherein the average peel strength between adjacent color-developing layers is less than 3.5 N / cm.

4. The recording medium according to claim 1, wherein the matrix resin includes a polycarbonate-based resin.

5. The recording medium according to claim 1, wherein the heating temperature is 120°C or higher and 200°C or lower.

6. The recording medium according to claim 1, wherein the heating temperature is 160°C or more and 200°C or less.

7. The recording medium according to claim 1, wherein the diffusion suppression layer is a resin layer that does not have tackiness in a standard atmosphere with a temperature of 23±1°C and a relative humidity of 50±5%.

8. The recording medium according to claim 1, wherein the Young's modulus of the diffusion suppression layer is 100 MPa or more.

9. The recording medium according to claim 1, wherein the Young's modulus of the diffusion suppression layer is 2000 MPa or more.

10. The recording medium according to claim 1, wherein the diffusion suppression layer is a resin layer having a pencil hardness of F or higher.

11. The recording medium according to claim 1, wherein the diffusion suppression layer has a glass transition temperature of 130°C or higher.

12. The recording medium according to claim 1, wherein the diffusion suppression layer comprises an amorphous resin.

13. The recording medium according to claim 1, wherein the diffusion suppression layer comprises a crystalline resin.

14. Multiple color-developing layers, At least one resin layer and Equipped with, The color-developing layer comprises an electron-donating color-developing compound, an electron-accepting color developer, and a matrix resin. The resin layer is provided between adjacent color-developing layers. The aforementioned resin layer includes an ultraviolet-curable resin or a thermosetting resin. A recording medium having at least one adhesive layer between the resin layer and one of the adjacent color-developing layers.

15. The recording medium described in claim 1, Substrate and Overlay layer and Equipped with, The recording medium is a laminate provided between the substrate and the overlay layer.

16. The laminate according to claim 15, wherein the substrate and the recording medium are bonded together by fusion or thermal adhesive, and the recording medium and the overlay layer are bonded together by fusion or thermal adhesive.

17. A card comprising the laminate according to claim 15 or 16.

18. The card according to claim 17, wherein the card is a security card, a financial settlement card, an ID card, or a personal transaction card.

19. An electronic device comprising a recording medium according to any one of claims 1 to 14.

20. A booklet comprising the recording medium described in any one of claims 1 to 14.

21. A passport comprising the recording medium described in any one of claims 1 to 14.

22. A wearable terminal comprising the recording medium described in any one of claims 1 to 14.

Images