JP2008049548A - Authenticity judging medium and article having the same, authenticity judging medium label, authenticity judging medium transfer sheet and authenticity judging medium transfer foil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an authenticity judging means which easily judges forgery, falsification or the like and, in addition, disables easy forgery. <P>SOLUTION: The authenticity judging medium has: an optical selectively reflecting layer having selectively reflecting properties for reflecting either a left-handed circularly polarized light or a right-handed circularly polarized light in incident light; a patterned layer, which reverses the rotational direction of the incident light; a holographed layer, and a reflecting layer in this order. The optical selectively reflecting layer, the patterned layer, the holographed layer and the reflecting layer are permeable to visible light and, at the same time, the reflecting layer has a refractive index, which is different from that of the holographed layer, to the visible light. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a medium for determining authenticity that can easily determine counterfeiting and falsification, and is difficult to counterfeit, and an article having the medium for determining authenticity. Furthermore, the present invention relates to a true / false determination medium label including the authenticity determination medium, a true / false determination medium transfer sheet, and a true / false determination medium transfer foil.

  For example, credit cards, deposit and saving cards, various types of cash vouchers, identification cards, and the like cause various troubles if they are forged or altered and used illegally. Therefore, in order to prevent damage caused by forgery or tampering, it is desirable to have a function that can identify the authenticity of itself. In addition, for example, luxury products such as wristwatches, leather products, precious metal products, jewelry, especially, what are said to be luxury brand products, audio products, electrical appliances, music software recorded on media, video software, game software, Computer software and the like are also subject to counterfeiting, and similarly, it is desirable to have a function that can identify authenticity.

  Conventionally, latent image patterns and holograms are frequently used for the purpose of enabling authenticity identification of various articles including the above-mentioned articles. The latent image pattern cannot be visually recognized in a normal state but can be visually recognized under specific conditions. Therefore, the latent image pattern can be used for authenticity determination and is also effective for preventing forgery. Further, the hologram has a manufacturing difficulty due to the precision of its structure, and therefore has a great effect of preventing forgery.

In recent years, an authenticity determination body having a cholesteric liquid crystal layer has been proposed as an alternative to a hologram (see Patent Document 1). Further, an authenticity determination medium combining a latent image pattern and a hologram (Patent Document 2) and an authenticity determination medium combining a latent image pattern and a cholesteric liquid crystal layer (see Patent Document 3) have also been proposed.
JP 2000-25373 A JP 2005-91786 A JP 2005-22231 A

  In the authenticity determination body described in Patent Document 1, the determination unit is still formed of an embossed hologram. According to the embossed hologram, although it is possible to form a precise pattern, the contact time between the embossed mold and the material to be embossed is made sufficiently long in order to sufficiently reproduce the unevenness of the hologram engraved in the embossed mold. Therefore, it is difficult to shorten the manufacturing time, and the manufacturing process of the embossing mold itself has a large number of steps, so that it is difficult to change the pattern of the determination unit.

  On the other hand, in the authenticity determination media described in Patent Documents 2 and 3, since the determination unit is formed of a latent image pattern formed of nematic liquid crystal or smectic liquid crystal, pattern formation or pattern change of the determination unit is easy. Furthermore, since the authenticity determination medium can perform both authenticity determination based on the latent image pattern and authenticity determination based on the reflectivity of the liquid crystal layer and the hologram layer in the background, the security is high and the anti-counterfeiting effect is high. Have However, in recent years, forgery means are becoming more sophisticated, and more effective forgery prevention means are required.

  Under such circumstances, it is an object of the present invention to provide a true / false determination means that can easily determine forgery or falsification and that cannot be easily counterfeited.

Means for achieving the object is as follows.
[1] A light selective reflection layer having a light selective reflection property that reflects either left circular polarization or right circular polarization of incident light, a pattern layer in which the rotation direction of incident light is reversed, a hologram forming layer, and a reflection layer. A medium for authenticity determination in this order,
The light selective reflection layer, the pattern layer, the hologram forming layer, and the reflection layer have transparency to visible light, and
The reflection layer is a true / false determination medium having a refractive index different from that of the hologram forming layer with respect to visible light.
[2] The medium for authenticity determination according to [1], wherein the light selective reflection layer is a cholesteric liquid crystal layer.
[3] The medium for authenticity determination according to [1] or [2], wherein the pattern layer is a smectic liquid crystal layer or a nematic liquid crystal layer.
[4] The authenticity determination medium according to any one of [1] to [3], wherein the reflective layer further includes a base layer on a surface opposite to the surface having the hologram forming layer.
[5] The authenticity determination medium according to [4], wherein the base layer is a colored layer.
[6] The authenticity determination medium according to any one of [1] to [5], and an authenticity layer having an adhesive layer on a surface opposite to the surface having the light selective reflection layer of the authenticity determination medium. False label media label.
[7] The medium label for authenticity determination according to [6], wherein the adhesive layer is a colored layer.
[8] A medium transfer sheet for authenticity determination having a substrate having a peelable surface and a medium label for authenticity determination according to [6] or [7],
The medium transfer sheet for authenticity determination, wherein the surface opposite to the surface having the adhesive layer of the medium label for authenticity determination and the peelable surface of the base material face each other.
[9] A medium transfer foil for authenticity determination having the heat-sensitive adhesive layer, the medium for authenticity determination according to any one of [1] to [5], and a base film in this order.
[10] An article having the authenticity determination medium according to any one of [1] to [5] in a visible manner.

  According to the authenticity determination medium of the present invention, authenticity determination based on the latent image pattern, authenticity determination based on the reflectivity of the light selective reflection layer of the background and the pattern of the hologram layer, and true / false determination based on the color change of the light selective reflection layer. A false determination can also be made.

Hereinafter, the present invention will be described in more detail.

[Authentication medium]
The authenticity determination medium of the present invention includes a light selective reflection layer having a light selective reflection property that reflects either left circularly polarized light or right circularly polarized light in incident light, a pattern layer in which the rotation direction of incident light is reversed, It has a hologram forming layer and a reflective layer in this order. The light selective reflection layer, the pattern layer, the hologram formation layer, and the reflection layer are transmissive to visible light, and the reflection layer has a refractive index different from that of the hologram formation layer with respect to visible light. Have. In the present invention, the “authentication medium” refers to a medium that can be used to discriminate between genuine products, counterfeit products, and falsified products. In the present invention, “having transparency with respect to visible light” means that the transmittance of visible light (wavelength: 380 nm to 780 nm) is, for example, 50% or more.

  The light selective reflection layer and the pattern layer are visible light transmissive. Therefore, when the authenticity determination medium of the present invention is observed from the light selective reflection layer side under natural light, the color change of the light selective reflection layer and the pattern of the hologram (formed by the hologram formation layer and the reflection layer) can be observed. However, the pattern layer is not visible at all or is only very unclear and becomes a latent image.

When a circularly polarizing plate is superimposed on the authenticity determination medium of the present invention, the pattern layer can be recognized as a clear image by the following mechanism according to the reflectivity of the light selective reflection layer.
For example, when the light selective reflection layer has the property of selectively reflecting right circularly polarized light, the entire true / false determination medium is colored in the color of the reflected light from the light selective reflection layer when the right circularly polarizing plate is overlapped and observed. Visible in state. For example, when the light selective reflection layer is a cholesteric liquid crystal layer, it appears colored based on the helical pitch of the cholesteric liquid crystal layer.
On the other hand, when the left circularly polarizing plate is overlapped and observed, incident light is not reflected by the light selective reflection layer but is transmitted through the layer. Since the light transmitted through the light selective reflection layer has its rotation direction reversed in the pattern layer, reflection from the pattern layer occurs. The authenticity determination medium of the present invention has a hologram forming layer and a reflective layer on the background of the pattern layer. By arranging a reflective layer (hologram formed by a hologram forming layer and a reflective layer) on the background of the pattern layer, it is possible to clearly recognize the image formed by the pattern layer. If the reflected light from the pattern layer is buried in the reflected light from the hologram, the pattern layer cannot be recognized as an image. Therefore, in the present invention, the hologram forming layer and the reflective layer are made visible light transmissive. Since the hologram formed in this way becomes visible light transmissive, the reflected light from the pattern layer can be visually recognized without being disturbed by the reflected light from the hologram as described above, and the pattern layer is recognized as a clear image. It becomes possible to do.
Although the aspect in which the light selective reflection layer selectively reflects right circularly polarized light has been described above, the present invention is not limited to the above aspect. When the light selective reflection layer has the property of selectively reflecting the left circularly polarized light, the color of the reflected light of the light selective reflection layer can be recognized by observing the left circular polarizing plate in an overlapping manner. By observing the polarizing plate in an overlapping manner, the pattern layer can be recognized as a clear image.
In addition, as a polarizing plate for visually confirming the pattern layer, any of a linear polarizing plate, a left circular polarizing plate, and a right circular polarizing plate may be used. Thus, the reflectivity of the light selective reflection layer can also be observed.

  The color of the light selective reflection layer changes depending on the viewing angle. However, when a hologram located under the light selective reflection layer reflects without transmitting visible light, the light selective reflection is caused by the influence of the reflected light from the hologram. It becomes difficult to visually recognize the color of the layer. On the other hand, since the hologram included in the authenticity determination medium of the present invention is visible light transmissive, the color change of the light selective reflection layer can be easily visually recognized without being disturbed by the reflected light from the hologram. Therefore, it is also possible to make a true / false determination by visually changing the color of the light selective reflection layer. Further, it is possible to obtain an authenticity determination medium having an excellent aesthetic appearance by utilizing the color tone of the light selective reflection layer. Furthermore, in the authenticity determination medium of the present invention, the authenticity determination can be performed based on the hologram pattern formed by the hologram forming layer and the reflective layer.

As described above, the authenticity determination medium of the present invention can perform authenticity determination based on the latent image pattern, the reflectivity and color change of the light selective reflection layer, and the hologram pattern. In addition, the fact that authenticity can be determined by the latent image pattern and the reflectivity of the light selective reflection layer cannot be easily identified visually, and is effective in preventing forgery.
Moreover, in the authenticity determination medium of the present invention, the material for forming each layer is generally difficult to obtain and the layer formation is not easy, so that the anti-counterfeiting effect is extremely high. Furthermore, having a complicated layer structure as described above is also effective in preventing forgery.
Thus, according to the present invention, it is possible to provide an authenticity determination medium that is easy to determine authenticity and that has an excellent anti-counterfeit effect.
Next, details of each layer included in the authenticity determination medium of the present invention will be described.

Pattern Layer The pattern layer is not particularly limited as long as it has visible light transparency and a property of inverting incident light, and can be formed from a known material. The pattern layer is preferably a smectic liquid crystal layer or a nematic liquid crystal layer. Here, the smectic liquid crystal layer is a layer containing smectic liquid crystal molecules, and the nematic liquid crystal layer is a layer containing nematic liquid crystal molecules, and the liquid crystal molecules are oriented so that incident light is inverted. Can be shown. As the liquid crystal molecules, liquid crystal molecules that can be used in a cholesteric liquid crystal layer to be described later can be used. In general, liquid crystal materials are difficult to obtain, and advanced alignment techniques are required. Therefore, it is effective for preventing forgery that the pattern layer is a liquid crystal layer.

  The liquid crystal layer can be formed by printing an ink composition containing liquid crystal molecules, preferably an ink composition comprising a solvent solution of these liquid crystal molecules, in a pattern by various printing methods. A liquid crystal layer can be obtained by applying and drying the ink composition on a substrate having orientation and a light selective reflection layer, and in particular a nematic liquid crystal layer on the light selective reflection layer which is a cholesteric liquid crystal layer. In the case of laminating the pattern layer, it is preferable to apply and dry the ink composition on a substrate or alignment film having orientation in order to satisfactorily align liquid crystal molecules in the pattern layer. Further, the liquid crystal molecules in the layer can be aligned by applying the ink composition on the alignment film and drying it.

The base material pattern layer can be directly laminated on the light selective reflection layer, but as described above, the pattern layer is formed directly on one surface of the base material or through an alignment film, and light is applied to the other surface. The selective reflection layer is preferably formed directly or via an alignment film. Details of the alignment film will be described later.
As the base material, a plastic base material having visible light permeability and a base material having little retardation are desirable. Specific examples include polyethylene terephthalate (PET), polycarbonate, polyvinyl alcohol, polysulfone, polyethylene, polypropylene, polystyrene, polyarylate, triacetyl cellulose (TAC), diacetyl cellulose, polyethylene-ethyl vinyl alcohol, and the like.

Alignment film An alignment film may be formed between the light selective reflection layer and the pattern layer. In this case, the alignment film plays a role of aligning the liquid crystal molecules in the pattern layer and the liquid crystal molecules in the light selective reflection layer to impart desired light reflectivity. Further, as described above, an alignment film can be formed on the surface of the substrate. Further, an alignment film can be formed between the hologram forming layer and the pattern layer in order to align the liquid crystal molecules in the pattern layer.
The alignment film is visible light transmissive and may be any material that can be generally used as an alignment film. For example, polyvinyl alcohol resin (PVA), polyimide resin, or the like can be used. The alignment film can be formed by applying a solvent solution of these resins by an appropriate application method and drying, followed by rubbing with a cloth, a brush, or the like. The alignment film functions as an adhesive layer when a substrate film, a pattern layer, a light selective reflection layer, or a hologram forming layer is selected as the alignment film, while the alignment film functions as an adhesive layer. The alignment film functions as a release layer. If the alignment film functions as a release layer, it can be used as a transfer foil. Also, for example, when used as a label in the configuration of a light selective reflection layer / base material / alignment film (peeling layer) / pattern layer / hologram forming layer / reflection layer / adhesive layer, if you try to peel it off after applying it to the object Since the top of the release layer is peeled off, it is difficult to peel off the whole medium for authenticity determination, and the base material is peeled off, so that the label cannot be reattached. Therefore, the function of the alignment film as a release layer is effective for preventing falsification.
However, since the liquid crystal layer can align liquid crystal molecules in the layer without an alignment film depending on the physical properties of the lower layer, the alignment film is not essential. For example, when a substrate made of a stretched film (for example, a PET film) is used, molecules in the liquid crystal layer can be aligned without an alignment layer. In this case, the same effect as described above can be obtained by providing a release layer on at least one surface of the substrate. Moreover, when laminating | stacking a light selective reflection layer and a pattern layer without a base material or an alignment film, a peeling layer can also be provided in the interface of both layers. As this release layer, for example, acrylic resin, vinyl chloride-vinyl acetate copolymer resin, polyester resin, polymethacrylate resin, polyvinyl chloride resin, cellulose resin, silicone resin, chlorinated rubber, casein, various surfactants, One or a mixture of two or more of metal oxides can be used. Among these, an acrylic resin having a molecular weight of about 20,000 to 100,000, or an acrylic resin and a vinyl chloride-vinyl acetate copolymer resin having a molecular weight of 8000 to 20000, and a polyester resin having a molecular weight of 1,000 to 5,000 as an additive. It is particularly preferable that the composition comprises ˜5% by weight. In particular, it is preferable that the peeling force between the pattern layer and the light selective reflection layer is 1 to 5 g / inch (90 ° peeling). Moreover, it is preferable that the thickness exists in the range of 0.1 micrometer-2 micrometers from surfaces, such as peeling force and foil cutting.

  Furthermore, the same effect as described above can also be obtained by easily peeling the surface of the substrate facing the light selective reflection layer and / or the surface facing the pattern layer. Some transparent films that can be used as the base material exhibit an adhesive strength that can be laminated with other layers, but usually a treatment for improving the adhesive strength is performed. Therefore, by not using this adhesive strength improving treatment or adjusting the degree thereof, by using a transparent film whose surface adhesive strength is intentionally lowered (easily peeled), The adhesive strength of can be reduced. If such a transparent film is used as a base material, since it peels on the easily peeled surface, the same effect as described above can be obtained.

  Examples of the adhesive strength improving treatment include corona discharge treatment, plasma treatment, flame treatment, primer coating treatment, and saponification treatment. Any processing can be performed using a known apparatus and method. The treatment conditions can be appropriately set so that an adhesive force can be applied to the surface of the base film so that it can be peeled off from the surface when it is peeled off. In addition, when a film having an adhesive strength that can be bonded to other layers even if untreated, such as a polyethylene terephthalate film, is used as a base material, it is peeled off from the base material surface by not performing the adhesive strength improving treatment. be able to.

Further, if the film thickness of the base film is excessively reduced or the components are adjusted and the strength of the base material itself is intentionally reduced, an external force is applied to the article to which the authenticity determination medium of the present invention is applied. If the medium is peeled off, the base material is destroyed, so that the light selective reflection layer and the pattern layer are separated. Also by this, the same effect as described above can be obtained.
As described above, providing a fragile portion (a layer included in the authenticity determination medium and a portion having the lowest strength among the interfaces between layers) between the light selective reflection layer and the pattern layer is to prevent forgery and falsification. It is valid.

Light selective reflection layer The light selective reflection layer may have any visible light transparency and light selective reflection that reflects either left circular polarization or right circular polarization of incident light, A cholesteric liquid crystal layer is preferred. Here, the cholesteric liquid crystal layer is a layer containing cholesteric liquid crystal molecules. In general, liquid crystal materials are difficult to obtain, and advanced alignment techniques are required. Therefore, if the light selective reflection layer is a cholesteric liquid crystal layer, a high forgery prevention effect can be obtained.

  When the light selective reflection layer is a cholesteric liquid crystal layer, a liquid crystal material to be used is not particularly limited, and a known material can be used. The cholesteric liquid crystal layer can be formed by dissolving a cholesteric liquid crystal material in an appropriate solvent, applying it by various printing methods, and drying it. At this time, an ultraviolet-polymerizable composition is prepared using a polymerizable cholesteric liquid crystal, and the obtained ultraviolet-polymerizable composition is applied by various printing methods, and after drying, it is polymerized by irradiation with ultraviolet rays. You can also.

  Specifically, as a material for forming the cholesteric liquid crystal layer, a three-dimensionally crosslinkable liquid crystalline polymerizable monomer molecule or polymerizable oligomer molecule can be used. A layer containing cholesteric liquid crystal molecules can be obtained by adding an arbitrary chiral agent to a predetermined polymerizable monomer molecule or polymerizable oligomer molecule.

  Examples of the three-dimensionally crosslinkable monomer molecule include a mixture of a liquid crystal monomer and a chiral compound as disclosed in, for example, JP-A-7-258638 and JP-T-10-508882. As a more specific example, for example, liquid crystalline monomers represented by the following general chemical formulas (1) to (11) can be used. In the case of the liquid crystalline monomer represented by the general chemical formula (11), X is preferably an integer in the range of 2 to 5.

  Moreover, as a chiral agent, a chiral agent as shown, for example by the following general chemical formula (12)-(14) can be used. In the case of the chiral agent represented by the general chemical formulas (12) and (13), X is preferably an integer in the range of 2 to 12, and in the case of the chiral agent represented by the general chemical formula (14), X Is preferably an integer in the range of 2-5.

  When oligomer molecules are used, a cyclic organopolysiloxane compound having a cholesteric phase as disclosed in, for example, JP-A-57-165480 can be used. For example, a cholesteric liquid crystal layer can be obtained by adding about several to 10% of a chiral agent to polymerizable monomer molecules or polymerizable oligomer molecules.

  In the true / false determination medium of the present invention, since the hologram located in the lower layer of the light selective reflection layer is visible light transmissive, the true / false determination by the color tone change of the light selective reflection layer is not hindered by the reflected light from the hologram. There is also an advantage that the color tone of the light selective reflection layer can be utilized. In particular, the liquid crystal layer can express a variety of colors by adjusting the type of liquid crystal molecules used, the amount of chiral agent added, etc., but liquid crystal materials are generally difficult to obtain, and advanced manufacturing techniques are required. Since it is required, it is difficult to reproduce the color of the liquid crystal layer. Therefore, as described above, it is effective for preventing counterfeiting that the hologram can be made visible light transmissive so that the color of the light selective reflection layer can be utilized. The cholesteric liquid crystal layer can be formed as a layer having a substantially uniform thickness, but can also be a pattern layer in which a pattern is formed depending on the presence or absence of the layer or a difference in thickness. The pattern layer can be formed using various printing methods.

The light selective reflection layer may be formed of two or more layers having different light reflectivities. For example, the light reflectivity can be changed by changing the thickness of a plurality of cholesteric liquid crystal layers or forming each layer using liquid crystal materials having different spiral pitches. When a cholesteric liquid crystal layer is formed from an ultraviolet polymerizable composition using a polymerizable cholesteric liquid crystal as described above, a polymerizable nematic liquid crystal and a chiral agent are used in combination, and at this time, the polymerizable nematic liquid crystal and the chiral agent are used. Cholesteric liquid crystal layers having different helical pitches can be formed by preparing and using ultraviolet polymerizable compositions having different blending ratios with the agent. Even when two or more kinds of cholesteric liquid crystal layers are provided in this way, each cholesteric liquid crystal layer can be formed as a layer having a substantially uniform thickness, but a pattern is formed depending on the presence or absence of the layer and the difference in thickness. It can also be a pattern layer. The pattern layer can be formed using various printing methods.
For example, both have light reflectivity that selectively reflects right circularly polarized light, but if two light selective reflection layers formed of different liquid crystalline compositions are laminated, the authenticity is determined via the right circularly polarizing plate. When the medium for use is observed, it is visually recognized in a colored state of the reflected light of the two light selective reflection layers, and when it is observed through the left circularly polarizing plate, the pattern layer is visible.

Hologram-forming layer The hologram-forming layer may be a layer having visible light transparency, and can be produced by forming fine relief irregularities of a relief hologram on one side of a layer made of a transparent resin material. Various resin materials such as various thermosetting resins, thermoplastic resins, and ionizing radiation curable resins can be selected as the transparent resin material for constituting the hologram forming layer. Examples of the thermosetting resin include unsaturated polyester resins, acrylic urethane resins, epoxy-modified acrylic resins, epoxy-modified unsaturated polyester resins, alkyd resins, and phenol resins. Examples of the thermoplastic resin include acrylate resin, acrylamide resin, nitrocellulose resin, and polystyrene resin. These resins can be used alone or as two or more types of copolymers. These resins may be used alone or in combination with two or more kinds of isocyanate resins, metal soaps such as cobalt naphthenate and zinc naphthenate, peroxides such as benzoyl peroxide and methyl ethyl ketone peroxide, benzophenone, acetophenone, anthraquinone, naphthoquinone, A heat or ultraviolet curing agent such as azobisisobutyronitrile or diphenyl sulfide may be blended. Examples of the ionizing radiation curable resin include epoxy acrylate, urethane acrylate, and acrylic-modified polyester. Other monofunctional or polyfunctional monomers, oligomers and the like can be conjugated to such ionizing radiation curable resins for the purpose of adjusting the cross-linking structure and viscosity.

  The hologram forming layer can be directly formed by developing the photosensitive resin material by performing interference exposure of the hologram. However, a relief hologram prepared in advance or a duplicate thereof, or a plating mold thereof is duplicated. Molding can also be performed by using it as a mold and pressing the mold surface against the resin material. When a thermosetting resin or ionizing radiation curable resin is used, it is cured by heating or irradiation with ionizing radiation while the uncured resin is kept in close contact with the mold surface, and the cured transparent film is peeled off after curing. The fine irregularities of the relief hologram can be formed on one side of the layer made of the resin material. In the present invention, a diffraction grating forming layer having a diffraction grating formed in a pattern by a similar method is also included in the hologram forming layer. A combination of the hologram forming layer and the diffraction grating forming layer is referred to as an optical diffraction structure layer.

Reflective Layer The reflective layer may be a layer having visible light transparency and a refractive index different from that of the hologram forming layer with respect to visible light. By the visible light transmissive hologram forming layer and the reflective layer, a visible light transmissive hologram can be formed, and the effects described above can be obtained.

  The refractive index of the reflective layer may be larger or smaller than the refractive index of the hologram forming layer, but the difference in refractive index between the two is preferably 0.1 or more, and preferably 0.5 or more. More preferably, it is 1.0 or more.

The reflective layer can be formed by a known method such as sublimation, vacuum deposition, sputtering, reactive sputtering, ion plating, electroplating, etc. along the fine irregularities of the relief hologram. Examples of the material constituting the reflective layer include titanium oxide (TiO ₂ ), zinc sulfide (ZnS), and Cu • Al composite metal oxide. In addition, a metal thin film having a thickness of 20 nm or less can also be used as the reflective layer because it has visible light permeability. As the material constituting the metal thin film, Al, Cr, Ti, Fe, Co, Ni, Cu, Ag, Au, Ge, Mg, Sb, Pb, Cd, Bi, Sn, Se, In, Ga, or A metal such as Rb, or an oxide or nitride of the metal can be used, and a reflective layer made of a metal thin film can be formed by combining one or more of these metals. Among these, Al, Cr, Ni, Ag, Au, or the like is particularly preferable.

Underlayer It is also possible to provide an underlayer on the surface of the reflective layer opposite to the surface having the hologram forming layer. As described above, in the authenticity determination medium of the present invention, the hologram is visible light transmissive. Therefore, since the color of the base layer can be visually recognized without being blocked by the hologram, a medium for determining authenticity of various colors by combining the color of the light selective reflection layer described above by adding a desired color to the base layer Can be obtained. Moreover, the visibility of a light selective reflection layer and a hologram can also be improved by providing a colored layer as a base layer. In addition, it is also possible to attach a design such as characters and figures to the underlayer. The underlayer can be formed from a material constituting an adhesive layer described later. In any case, the base layer having a desired color tone can be obtained by adding an appropriate amount of pigment, dye or the like. As pigments to be added, inorganic pigments such as Gunjo, Cadmium Yellow, Bengala, Chrome Yellow, Lead White, Titanium White, Carbon Black, and other organic pigments such as azo, triphenylmethane, quinoline, anthraquinone, phthalocyanine, etc. As dyes, azo dyes, anthraquinone dyes, indigoid dyes, sulfur dyes, triphenylmethane dyes, xanthene dyes, xanthene dyes, alizarin dyes, acridine dyes, quinoneimine dyes (azine dyes, oxazine dyes, thiazine dyes) , Thiazole dyes, methine dyes, nitro dyes, nitroso dyes, and the like. The density | concentration of the dye and pigment to add can be adjusted according to a desired color tone.

  The authenticity determination medium of the present invention may have a layer other than the above-mentioned layers at an arbitrary position, if necessary. For example, it can also have a well-known protective layer and various functional layers.

  In the authenticity determination medium of the present invention, the thickness of each layer is appropriately set and is not particularly limited. For example, the light selective reflection layer has a thickness of 0.1 to 30 μm, a pattern layer. Is 0.1 to 20 μm, the hologram forming layer is 0.1 to 20 μm, and the reflective layer is 1 to 10,000 nm. Moreover, when providing a base material, an alignment film, and a base layer, the thickness of a base material is 3-250 micrometers, for example, the thickness of an alignment film is 0.05-20 micrometers, for example, and the thickness of a base layer is 0. It can be 1-50 micrometers.

[Authentication media label, authenticity media transfer sheet]
Furthermore, the present invention relates to a true / false determination medium label of the present invention and a true / false determination medium label having an adhesive layer on a surface opposite to the surface having the light selective reflection layer of the true / false determination medium. The authenticity determination medium label can be produced by laminating an adhesive layer on the authenticity determination medium of the present invention. The pressure-sensitive adhesive layer is not particularly limited, and can be formed using a known adhesive such as an acrylic adhesive, a natural rubber adhesive, a synthetic rubber adhesive, or a silicone rubber adhesive. The pressure-sensitive adhesive layer is preferably a heat-sensitive adhesive layer or a pressure-sensitive adhesive layer. The thickness of the adhesive layer can be, for example, about 0.1 to 40 μm. The pressure-sensitive adhesive layer can also function as the above-described underlayer, but an adhesive layer can be provided separately from the above-described underlayer.

  Further, the medium label for authenticity determination may be provided with a release paper on the adhesive layer in order to protect the adhesive layer until use. As the release paper, for example, a material obtained by coating a base material such as paper or film with a silicon-based resin, wax, paraffin, or the like can be used. The medium label for authenticity determination can be used after being cut into an appropriate size by die cutting or the like.

  Furthermore, the present invention relates to a true / false determination medium transfer sheet having a substrate having a peelable surface and the true / false determination medium label of the present invention. In the authenticity determination medium transfer sheet, the surface opposite to the surface having the adhesive layer of the authenticity determination medium label and the peelable surface of the base material face each other. A well-known thing can be used as a base material which has a peelable surface.

  The medium label for authenticity determination and the medium transfer sheet for authenticity determination of the present invention can be applied to various articles. The label is applied by sticking the pressure-sensitive adhesive layer toward the article serving as the adherend, and the transfer sheet is bonded to the article side serving as the adherend. It can be applied by peeling the material.

[Media transfer foil for authenticity determination]
Furthermore, this invention relates to the medium transfer foil for authenticity determination which has a heat sensitive adhesive layer, the authenticity determination medium of this invention, and a base film in this order. The transfer foil can be produced by providing a heat-sensitive adhesive layer on one surface of the authenticity determination medium of the present invention and providing a base film on the other. In the transfer foil, it is preferable that the heat-sensitive adhesive layer is provided on the reflective layer, and the base film is provided on the light selective reflection layer. The transfer foil may adhere the medium for authenticity determination and the adherend of the present invention by bringing the heat-sensitive adhesive layer and the adherend into contact with each other and applying heat from the base film side. it can.

  The base film is not particularly limited as long as it has resistance to heat and pressure applied during thermal transfer. For example, polyethylene film, polypropylene film, polyethylene fluoride film, polyvinylidene fluoride film, polyvinyl chloride film, polyvinylidene chloride film, ethylene-vinyl alcohol copolymer film, polyvinyl alcohol film, polymethyl methacrylate film, polyether sulfone film Polyether ether ketone film, polyamide film, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer film, polyester film such as polyethylene terephthalate film, and transparent resin film such as polyimide film can be used.

  The heat-sensitive adhesive layer can be formed using a known thermocompression adhesive. Examples of such an adhesive include ethylene-vinyl acetate copolymer resin (EVA), polyamide resin, polyester resin, polyethylene resin, ethylene-isobutyl acrylate copolymer resin, butyral resin, polyvinyl acetate and its copolymer resin, Cellulosic resin, polymethyl methacrylate resin, polyvinyl ether resin, polyurethane resin, polycarbonate resin, polypropylene resin, epoxy resin, phenol resin, styrene butadiene styrene block copolymer (SBS), styrene isoprene styrene block copolymer (SIS) Further, thermoplastic resins such as styrene ethylene butylene styrene block copolymer (SEBS) and styrene ethylene propylene styrene block copolymer (SEPS) can be used. Among these, a layer that can be heat-sealed at a temperature of 180 ° C. or lower is preferable, and an ethylene-vinyl acetate copolymer resin (EVA) having an acetic acid content of 25% or more is preferably used.

  The said transfer foil can also have a peeling layer between a base film and the medium for authenticity determination of this invention. Thereby, it becomes possible to remove a base film after thermocompression bonding. As the release layer, for example, acrylic resin, vinyl chloride-vinyl acetate copolymer resin, polyester resin, polymethacrylate resin, polyvinyl chloride resin, cellulose resin, silicone resin, chlorinated rubber, casein, various surfactants, metal From an oxide or the like, one or a mixture of two or more can be used. Among them, an acrylic resin having a molecular weight of about 20,000 to 100,000, or an acrylic resin and a vinyl chloride-vinyl acetate copolymer resin having a molecular weight of 8,000 to 20,000, and a polyester resin having a molecular weight of 1,000 to 5,000 as an additive is used. It is particularly preferable that the composition comprises ˜5% by weight. Moreover, it is preferable that the said peeling layer is a thing from which the peeling force between the said base film and a reflection layer will be 1-5 g / inch (90 degree peeling). Moreover, it is preferable that the thickness exists in the range of 0.1 micrometer-2 micrometers from surfaces, such as peeling force and foil cutting.

  The authenticity determination medium of the present invention can be applied to various articles in the form of the label, sheet, transfer foil and the like as described above. The article to which the authenticity determination medium of the present invention is applied can be various articles that are required to prevent forgery and tampering. Specifically, cash certificates such as gift certificates, securities, stock certificates, tickets, various cards such as credit cards, prepaid cards, ID cards, tickets, banknotes, passports, identification cards, public competition voting tickets, video software, personal computers Authenticity determination seals used in software, etc., threaded paper such as thread paper.

  The authenticity determination medium of the present invention can be applied to an article that is an authenticity determination target so as to be visible. Here, “visually visible” means that the existence of the authenticity determination medium can be recognized from the outside. FIG. 1 shows a specific example of an article having the authenticity determination medium of the present invention so as to be visible.

  FIG. 1 (a) is an information recording body capable of authenticity determination, having the authenticity determination medium of the present invention on a part of the surface. The information recording body is a sheet-like material based on paper, plastic sheet, etc., for example, as shown in FIG. Information such as a pattern is formed and recorded by means such as printing.

  In FIG. 1B, the medium for authenticity determination of the present invention is built in a sheet-like material in advance so that it can be visually recognized, and a concave opening that does not become a through-hole in paper or a plastic sheet. And a medium for determining authenticity can be seen from the opening. In order to facilitate the application of the authenticity determination medium, for example, it is cut into a very narrow width of about 0.5 mm to 5 mm (vertically long thread shape in FIG. 1B). Can be applied by providing an opening in the layer constituting the surface layer and sandwiching a thread-like authenticity determination medium between the layers of the sheet-like material. In the thread-like authenticity determination medium, if necessary, the surface of the base material is colored with a dark color or the like for the purpose of improving the visibility when irradiated with circularly polarized light, and is incorporated in a sheet-like material. In order to ensure adhesion between the thread-like authenticity determination medium and the sheet-like material in the state, an adhesive layer, preferably a heat-sensitive adhesive layer, is preferably laminated on one side or both sides. Such a sheet-like material to which a medium for authenticity determination is applied is suitable for use in an information recording medium, particularly a printed matter having a cash voucher or other economic value.

  Hereinafter, the present invention will be described with reference to examples. However, this invention is not limited to the aspect shown in the Example.

[Example 1]
(1) Formation of light selective reflection layer (cholesteric liquid crystal layer) Prepare a PET film, apply cholesteric liquid crystal ink on the entire surface of one side, and dry it to develop a cholesteric liquid crystal phase. Thus, a cholesteric liquid crystal layer having a thickness of 2 μm that reflects only the right circularly polarized light was formed.

(2) Formation of the pattern layer By performing gravure printing on the surface opposite to the surface on which the light selective reflection layer of the PET film is formed using a polymerizable nematic liquid crystal ink, drying, and then irradiating with ultraviolet rays, Letters and designs were formed to obtain a pattern layer having a thickness of 2 μm.

  A transparent ultraviolet curable resin composition is applied onto the surface on which the pattern layer is formed, and the transparent ultraviolet curable resin composition is cured by irradiating with ultraviolet rays while the mold surface of the relief hologram replication mold is in contact. Then, a relief hologram was formed, and then ZnS was vacuum-deposited on the surface of the relief hologram to form a visible light transmissive reflective layer having a thickness of 400 nm.

When the authenticity determination medium obtained by the above process was observed from the light selective reflection layer printing surface side, the latent image could hardly be observed, but the color change of the cholesteric liquid crystal layer was visible. Moreover, the pattern of the hologram was also confirmed.
Further, when the right circularly polarizing plate was superimposed on the obtained authenticity determination medium, it became a bright state colored based on the helical pitch of the cholesteric liquid crystal layer. However, no latent image was observed in this state. On the other hand, when the left circularly polarizing plate was overlapped and observed, the latent image could be clearly recognized. The outline of the above is shown in FIG.

[Example 2]
An adhesive layer (transparent or black) was provided on the reflective layer of the authenticity determination medium obtained in Example 1 by adhesive processing, and punching was performed to obtain an authenticity determination medium label.

[Example 3]
The authenticity determination medium obtained in Example 1 was rolled into a paper so that the light selective reflection layer was positioned on the surface side, and a thread paper was obtained.

[Example 4]
A colored underlayer was provided on the reflective layer of the authenticity determination medium obtained in Example 1, and then the paper was cut into a paper so that the light selective reflection layer was located on the surface side to obtain a thread paper.

The specific example of the article | item which has the authenticity determination medium of this invention visibly is shown. The outline of the latent image visual recognition method in Example 1 is shown.

Claims (10)

A light selective reflection layer having a light selective reflection property that reflects either left circular polarization or right circular polarization of incident light, a pattern layer that reverses the rotation direction of incident light, a hologram formation layer, and a reflection layer in this order A medium for authenticity determination,
The light selective reflection layer, the pattern layer, the hologram forming layer, and the reflection layer have transparency to visible light, and
The reflection layer is a true / false determination medium having a refractive index different from that of the hologram forming layer with respect to visible light. The authenticity determination medium according to claim 1, wherein the light selective reflection layer is a cholesteric liquid crystal layer. The authenticity determination medium according to claim 1, wherein the pattern layer is a smectic liquid crystal layer or a nematic liquid crystal layer. The authenticity determination medium according to any one of claims 1 to 3, wherein the reflective layer further includes a base layer on a surface opposite to the surface having the hologram forming layer. The medium for authenticity determination according to claim 4, wherein the base layer is a colored layer. The authenticity determination medium according to any one of claims 1 to 5, and an authenticity determination having an adhesive layer on a surface opposite to the surface having the light selective reflection layer of the authenticity determination medium. Media label. The authenticity determination medium label according to claim 6, wherein the adhesive layer is a colored layer. A medium transfer sheet for authenticity determination having a substrate having a peelable surface and a medium label for authenticity determination according to claim 6 or 7,
The medium transfer sheet for authenticity determination, wherein the surface opposite to the surface having the adhesive layer of the medium label for authenticity determination and the peelable surface of the base material face each other. A medium transfer foil for authenticity determination having a heat-sensitive adhesive layer, the medium for authenticity determination according to any one of claims 1 to 5, and a base film in this order. An article having the authenticity determination medium according to any one of claims 1 to 5 in a visible manner.

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