JP4853056B2 - Authenticity determination medium and article having the same, authenticity determination medium label, authenticity determination medium transfer sheet, and authenticity determination medium transfer foil - Google Patents

Description

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

  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, holograms are frequently used for the purpose of enabling authenticity identification of various articles including the above articles. In recent years, an authenticity determination body having a cholesteric liquid crystal layer has been proposed as an alternative to a hologram (see, for example, Patent Document 1).

  However, in the authenticity determination body described in Patent Document 1, the determination portion 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. In addition, it is difficult to shorten the manufacturing time, and the manufacturing process of the embossing mold itself has a large number of steps, and thus there is a disadvantage that it is difficult to change the pattern of the determination unit.

Therefore, the inventors have difficulty in shortening the manufacturing time when forming the determination part with an embossed hologram, and there are many steps during the manufacture of the embossed mold, making it difficult to change the pattern of the determination part. As a true / false determination medium that can eliminate this problem, cholesteric liquid crystals with different hues when layered with right-handed circularly polarized light and layered with left-handed circularly polarized light are stacked via a retardation layer. A medium for determination was proposed (see Patent Document 2). The medium for authenticity determination described in Patent Document 2 can perform authenticity determination by showing different hues when, for example, the right circularly polarizing plate is overlapped with the left circularly polarizing plate, and is high. It has security. In addition, since liquid crystal materials are generally difficult to obtain, the effect of preventing forgery is great. However, since counterfeiting means are becoming increasingly sophisticated in recent years, more effective forgery prevention means are required.
JP 2000-25373 A JP 2005-297449 A

  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 first light selective reflection layer having a light reflecting property that reflects either left circular polarization or right circular polarization of incident light, a phase difference layer, and left circular polarization and right circular polarization of incident light A true / false determination medium having a second light selective reflection layer having light reflectivity for reflecting any one of
It has a fragile portion between the first light selective reflection layer and the second light selective reflection layer, and
The fragile portion may authenticity determination medium characterized Rukoto included in the retardation layer.
[2] The authenticity determination medium according to [1], wherein the second light selective reflection layer has a center wavelength of reflected light different from a center wavelength of reflected light reflected from the first light selective reflection layer. .
[ 3 ] The retardation layer comprises at least two layers,
The authenticity according to [ 1 ] or [2] , wherein the fragile portion is any one of the layers included in the retardation layer, or a surface facing the other layer of the layer included in the retardation layer. Judgment medium.
[ 4 ] Any one of [1] to [ 3 ], further comprising a hologram layer on a surface opposite to the surface facing the retardation layer of the first light selective reflection layer or the second light selective reflection layer. The medium for authenticity determination.
[ 5 ] The medium for authenticity determination according to [ 4 ], further including a reflection layer on a surface of the hologram layer opposite to the surface facing the light selective reflection layer.
[ 6 ] An authenticity determination medium label having an authenticity determination medium according to any one of [1] to [ 5 ] and an adhesive layer on at least one surface of the authenticity determination medium.
[ 7 ] A medium transfer sheet for authenticity determination having a substrate having a peelable surface and a medium label for authenticity determination according to [ 6 ],
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.
[ 8 ] 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.
[ 9 ] An article having the authenticity determination medium according to any one of [1] to [ 5 ] in a visible manner.

  The authenticity determination medium of the present invention can be separated between two light selective reflection layers when it is to be peeled off after being applied to an article. Therefore, it cannot be reused as a medium for authenticity determination after peeling, has high security, and is extremely effective in preventing forgery and tampering.

Hereinafter, the present invention will be described in more detail.
[Authentication medium]
The authenticity determination medium of the present invention includes a first light selective reflection layer having a light reflectivity that reflects either left circularly polarized light or right circularly polarized light in incident light, a retardation layer, and incident light. A medium for authenticity determination having a second light selective reflection layer having light reflectivity for reflecting either left circularly polarized light or right circularly polarized light in this order, the first light selective reflection layer and the second light selective reflection layer It has a fragile portion between the light selective reflecting layer, and the fragile portion is, Ru contained in the retardation layer. In the present invention, “authentication medium” refers to a medium that can be used to discriminate between genuine products, counterfeit products, and falsified products. In addition, the “fragile portion” refers to a portion having the lowest strength among the layers included in the authenticity determination medium and the interface between the layers.
Since the medium for authenticity determination of the present invention has a fragile portion between two layers, if it is applied to an article and then peeled off by applying an external force, the first light selective reflection layer and the second light are separated from the fragile portion as a boundary. The reflective layer is separated. Therefore, only the medium is peeled from the genuine product to which the authenticity determination medium of the present invention is applied, and the peeled medium can be prevented from being applied to a counterfeit product or a tampered product.
Details of the authenticity determination medium of the present invention will be described below.

Light selective reflection layer The first light selective reflection layer and the second light selective reflection layer both have light reflectivity for reflecting either left circularly polarized light or right circularly polarized light in incident light. In the authenticity determination medium of the present invention, two layers having such properties are arranged via a retardation layer.

  The phase difference layer is a layer that birefrings incident light to generate different phases depending on the polarization direction, thereby providing a phase difference. Birefringence is a phenomenon that occurs because the refractive index of a medium is not uniform depending on the polarization direction, and the phase difference σ of light transmitted through such a medium is given by σ = 2π (ne−no) d / λ. It is known. Here, ne is the extraordinary ray refractive index, no is the ordinary ray refractive index, d is the thickness of the medium, and λ is the wavelength of the light. That is, for a medium having a certain thickness d, the phase difference σ depends on the wavelength λ of light. When right circularly polarized light having a wavelength λ = 2 (ne-no) d is incident on the retardation layer, a phase difference σ = π (that is, ½ wavelength) is given while transmitting the right circularly polarized light. Therefore, the incident right circularly polarized light is converted into left circularly polarized light and emitted, and the incident left circularly polarized light is converted into right circularly polarized light and emitted.

  In the authenticity determination medium of the present invention, since the two light selective reflection layers are provided via a retardation layer, different colors are obtained when the right circularly polarizing plate and the left circularly polarizing plate are stacked. Indicates. It is preferable that the two light selective reflection layers have light reflectivity for reflecting circularly polarized light in the same direction as viewed from one side of the authenticity determination medium. Below, the authenticity determination method using the authenticity determination medium of this invention is demonstrated based on FIG.

FIG. 1 is a cross-sectional view showing an example of the authenticity determination medium of the present invention. In the embodiment shown in FIG. 1, each of the two light selective reflection layers has light reflectivity that reflects right circularly polarized light in incident light.
As shown in FIG. 1, when natural light is incident from the light selective reflection layer A side, the natural light includes right circularly polarized light and left circularly polarized light. Therefore, only the right circularly polarized light is selected by the action of the light selective reflective layer A. Is reflected. Therefore, when the right circularly polarizing plate is stacked on the light selective reflection layer A, this reflected light (right circularly polarized light) can be observed through the right circularly polarizing plate.
Further, of the natural light incident from the light selective reflection layer A side, the left circularly polarized light passes through the light selective reflection layer A without being reflected by the light selective reflection layer A. The transmitted left circularly polarized light is converted into right circularly polarized light through a retardation layer (“left → right” in the figure indicates conversion from left circularly polarized light to right circularly polarized light). The converted right circularly polarized light is reflected by the light selective reflection layer B. This reflected light (right circularly polarized light) is transmitted again through the retardation layer 2 and converted into left circularly polarized light (“right → left” in the figure indicates conversion from right circularly polarized light to left circularly polarized light. ). The converted left circularly polarized light is emitted through the light selective reflection layer A. Therefore, when the left circularly polarizing plate is superimposed on the light selective reflection layer A, the emitted light (left circularly polarized light) can be observed through the left circularly polarizing plate.
As described above, the authenticity determination medium shown in FIG. 1 can observe light having different processes as described above by using the right circularly polarizing plate or the left circularly polarizing plate alone. Although this property cannot be visually recognized, it can be easily discriminated using a polarizing plate, and is therefore effective for determining authenticity. Furthermore, it is preferable that the two light selective reflection layers have different center wavelengths of reflected light. If the center wavelength of the reflected light is different, the color of the reflected light observed when the right circularly polarizing plate is superimposed is different from the color of the reflected light observed when the left circularly polarizing plate is superimposed. Whether the plate is used or when the left circularly polarizing plate is used can also be used to make a true / false determination based on the difference in the color of the light, and a higher authentic product identification function can be obtained.

  In addition, when the two light selective reflection layers have reflectivity with respect to circularly polarized light in different directions, when either the right circularly polarizing plate or the left circularly polarizing plate is used individually, either one of the circularly polarizing plates is overlapped. In this case, no reflected light is observed and the color becomes black. Therefore, when one circularly polarizing plate is overlapped, reflected light is observed, but when the other circularly polarizing plate is overlapped, the reflected light is not observed. Can do.

  The light selective reflection layer is not particularly limited as long as it has the light reflectivity described above, and can be, for example, a cholesteric liquid crystal layer. A cholesteric liquid crystal layer is a layer containing cholesteric liquid crystal molecules, and can exhibit light reflectivity for reflecting either left circularly polarized light or right circularly polarized light in incident light. Note that the fact that the light selective reflection layer is a liquid crystal layer has an advantage that it is possible to make a true / false judgment by visually changing the color of the liquid crystal. In addition, liquid crystal materials are generally difficult to obtain, and a high degree of anti-counterfeiting effect can be obtained because a high degree of alignment technology is required.

  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. The cholesteric liquid crystal layer can be formed, for example, as a layer having a substantially uniform thickness on the retardation layer, but can also be a pattern layer in which a pattern is formed depending on the presence or absence of the layer and the thickness. The pattern layer can be formed using various printing methods.

  The light reflectivity of each of the two light selective reflection layers can be adjusted by changing the thickness of each cholesteric liquid crystal layer or forming each layer using liquid crystal materials having different helical 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.

Retardation layer The retardation layer is not particularly limited as long as it can birefring incident light, generate different phases depending on the polarization direction, and impart a phase difference, for example, a transparent film, a nematic liquid crystal layer, or It can be composed of a laminate of a nematic liquid crystal layer and a transparent film.

  The retardation layer can be composed of, for example, nematic liquid crystal, and can be formed by various printing methods using an ink composition containing nematic liquid crystal, preferably an ink composition comprising a solvent solution of nematic liquid crystal. it can. In addition, the retardation layer can be composed of only a nematic liquid crystal layer, or a laminate in which a nematic liquid crystal layer is laminated on the surface of a transparent film having orientation by itself can be used as the retardation layer. . Alternatively, a laminate obtained by laminating a nematic liquid crystal layer on a transparent film via an alignment film can be used as the retardation layer. Details of the alignment film will be described later.

  As the transparent film, a film having solvent resistance and heat resistance that can withstand processing when producing a medium for determining mechanical strength and authenticity is preferable. Although it is not limited because it depends on the purpose of use, a film-like or sheet-like plastic is preferable. For example, various plastic films such as polyethylene terephthalate (PET), polycarbonate, polyvinyl alcohol, polysulfone, polyethylene, polypropylene, polystyrene, polyarylate, triacetyl cellulose (TAC), diacetyl cellulose, and polyethylene / vinyl alcohol can be exemplified. . Among these, a polyethylene terephthalate film is preferable because it can be used alone as a retardation layer.

  When the light selective reflection layer is a cholesteric liquid crystal layer, an alignment film can be laminated on one side or both sides of the retardation layer as necessary. In addition, an alignment film can be used to align the nematic liquid crystal layer as described above. Any alignment film may be used as long as it can be generally used as an alignment film, such as polyvinyl alcohol resin (PVA) or polyimide resin. The alignment film can be formed by applying a solvent solution of these resins to a transparent film by an appropriate application method and drying, followed by rubbing with a cloth, a brush, or the like. Depending on the physical properties of the retardation layer, liquid crystal molecules in the cholesteric liquid crystal layer can be aligned without an alignment film, and thus the alignment layer is not essential. For example, when a stretched film (for example, a PET film) is used as the retardation layer, the liquid crystal molecules in the cholesteric liquid crystal layer can be aligned without an alignment film.

Fragile portion The authenticity determination medium of the present invention has a fragile portion between the first light selective reflection layer and the second light selective reflection layer. By having a fragile portion between both layers, when an external force is applied to an article to which the authenticity determination medium of the present invention is applied and the medium is peeled off, the first light selective reflection layer and the second light are separated from the fragile portion as a boundary. The selective reflection layer is separated. Thereby, it is possible to prevent the medium itself from being peeled off and reused for forgery or alteration. The fragile portion is a portion having the lowest strength among the layers included in the authenticity determination medium and the interface between the layers, and the strength can be appropriately set according to the strength of each layer and the adhesion strength between the layers. it can.

In the reference aspect, the fragile portion may be a release layer provided on at least one surface of the retardation layer. 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 retardation 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.

  As described above, in the authenticity determination medium of the present invention, an alignment film can be provided on one side or both sides of the retardation layer. If this alignment film has high tackiness, the alignment film functions as an adhesive layer, whereas if the tackiness is low, it functions as a release layer. Therefore, when an alignment film with low adhesiveness is used, the alignment film can function as a fragile portion. The tackiness (peelability) of the alignment film can be appropriately adjusted depending on the material used, the film thickness, and the like.

Furthermore, in the reference aspect, the weakened portion may be a surface of the retardation layer that faces the first light selective reflection layer and / or a surface that faces the second light selective reflection layer. By making the phase difference layer surface facing the first light selective reflection layer and / or the phase difference layer surface facing the second light selective reflection layer easy to peel, the surface can be made a fragile portion.

  Some transparent films that can be used for the retardation layer exhibit an adhesive strength that can be laminated with other layers, but usually a treatment for improving the adhesive strength is performed. Therefore, in the present invention, by using a transparent film in which the adhesive strength of the surface is intentionally lowered (easily peeled) by not performing this adhesive strength improving treatment or adjusting the degree thereof, the transparent film And the adhesive force with other layers can be reduced. If such a transparent film is used as a retardation layer, the easily peeled surface can function as a fragile portion.

  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 the surface of the retardation layer can be provided with an adhesive force that can be bonded to other layers but can become a fragile portion. In addition, when a film having an adhesive strength that can be adhered to other layers even if not treated, such as a polyethylene terephthalate film, is used as a retardation layer, the surface of the retardation layer is not treated by performing an adhesive strength improving treatment. It can function as a vulnerable part.

Further, false determination medium of the present invention, including the fragile portion in the phase difference layer. For example, the strength of the retardation layer can be intentionally reduced by excessively reducing the thickness of the retardation layer or adjusting the components. In this case, the retardation layer itself functions as a weak part. When a low-strength retardation layer is used in this way, the retardation layer is destroyed when an external force is applied to an article to which the authenticity determination medium of the present invention is applied to peel off the medium. The light selective reflection layer and the second light selective reflection layer are separated. Thereby, it is possible to prevent the medium itself from being peeled off and reused for forgery or alteration.

  As described above, when the retardation layer is composed of a plurality of layers, any one of the layers included in the retardation layer can be a fragile portion. For example, in the case where a laminate in which a nematic liquid crystal layer is laminated on a transparent film via an alignment film is used as a retardation layer, the alignment film can be made to function as a release layer (fragile portion) as a layer having a low adhesive force. it can. Moreover, when using the phase difference layer containing the transparent film by which the surface was easily peeled as mentioned above, the surface which opposes the other layers (alignment film, nematic liquid crystal layer, etc.) of a transparent film is made into a weak part. Can function.

Hologram Layer The authenticity determination medium of the present invention may further include a hologram layer on a surface opposite to the surface facing the phase difference layer of the first light selective reflection layer or the second light selective reflection layer. . By combining the light selective reflection layer and the hologram layer, security can be further improved.

  The hologram layer can be produced by forming the fine irregularities of the relief hologram on one side of a layer made of a transparent resin material. As a transparent resin material for constituting the hologram layer, various resin materials such as various thermosetting resins, thermoplastic resins and ionizing radiation curable resins can be selected. 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 are used alone or as two or more kinds of copolymers. In addition, these resins are used alone, or two or more kinds of various isocyanate resins, metal soaps such as cobalt naphthenate and zinc naphthenate, peroxides such as benzoyl peroxide, 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.

  In order to form a hologram layer using the above resin material, it can be directly formed by developing the photosensitive resin material by performing interference exposure of the hologram, but a relief hologram prepared in advance or a duplicate thereof. Alternatively, the plating can be performed by using a plating mold or the like as a replication 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 into a pattern by a similar method and having a pattern is also included in the hologram 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 authenticity determination medium of the present invention may further include a reflective layer on the surface of the hologram layer opposite to the surface facing the light selective reflection layer. The reflective layer can be formed along the fine irregularities of the relief hologram described above. As the reflective layer, either a reflective metal thin film or a transparent layer having a light refractive index different from that of the hologram layer can be used. When the former is used, an opaque hologram is used, and when the latter is used, A transparent hologram can be obtained, and in any case, a reflection hologram with improved visibility when viewed by illumination from the viewer side can be obtained.

The reflective layer can be formed by a known method such as sublimation, vacuum deposition, sputtering, reactive sputtering, ion plating, or electroplating.
The materials constituting the reflective metal thin film include Al, Cr, Ti, Fe, Co, Ni, Cu, Ag, Au, Ge, Mg, Sb, Pb, Cd, Bi, Sn, Se, In, Ga, Alternatively, metals such as Rb, or oxides or nitrides of these metals can be used, and a reflective 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, and the film thickness is preferably 1 nm to 10,000 nm, more preferably 2 nm to 200 nm.

As a material constituting the transparent layer having a light refractive index different from that of the hologram layer, a resin material of the hologram layer and a transparent material having a different light refractive index can be used. The refractive index of the light of the transparent material may be larger or smaller than the refractive index of the light of the resin of the hologram layer, but the difference in the refractive index of light with the hologram layer may be 0.1 or more. More preferably, it is 0.5 or more, and particularly preferably 1.0 or more. Specific examples of the material preferably used include titanium oxide (TiO ₂ ), zinc sulfide (ZnS), Cu · Al composite metal oxide, and the like. Since a metal thin film having a thickness of 20 nm or less also has transparency, it can be used as a material constituting a transparent layer having a light refractive index different from that of the hologram layer.

  The reflection layer can be provided on the entire surface of the hologram layer opposite to the surface facing the light selective reflection layer, but it can also be provided partially. By providing the reflective layer partially, a hologram image corresponding to the reflective layer portion can be obtained, so that a medium for authenticity determination with high decorativeness can be obtained. For example, when a water-soluble ink is provided in a pattern, and then a metal layer is provided and washed with water, the metal layer provided on the water-soluble ink is washed and removed, and metal deposition is performed only on the portion where the water-soluble ink did not exist Remain. Thereby, a reflective layer can be provided in a desired portion on the hologram layer. Alternatively, the reflective layer can be partially provided by providing a metal layer on the entire surface of the hologram layer, then providing a pattern layer (resist layer) with an acid-resistant or alkali-resistant resin, and etching. In this case, the metal vapor deposition film remains in the portion where the resist layer exists.

  In the authenticity determination medium of the present invention, by configuring each layer (light selective reflection layer, phase difference layer, etc.) positioned above the hologram layer so as to have a light transmittance that allows the hologram layer to be visually recognized, In addition to the difficulty in manufacturing based on the appearance and characteristics of the hologram, it is possible to determine authenticity by double means using the right circularly polarizing plate and the left circularly polarizing plate, respectively. Such an authenticity determination medium has an advantage that authenticity can be identified with higher reliability.

  In addition, when the medium for authenticity determination of the present invention is observed using a right circularly polarizing plate and when observed using a left circularly polarizing plate, the effect of seeing reflected light of different colors is further clarified. In order to improve the visibility of the hologram, for example, a resin layer colored in a dark color such as black is used on the lower layer side of each layer for the purpose of It is preferable to laminate a dark color layer. In the medium label for authenticity determination to be described later, a dark color layer may be laminated between the reflective layer and the adhesive layer, or a dark color colored in a dark color such as black instead of laminating a separate dark color layer. You may comprise an adhesion layer using an adhesive agent.

  Furthermore, the authenticity determination medium of the present invention can 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 set according to the use and is not particularly limited. The thickness of the first and second light selective reflection layers is, for example, 0.1-30 μm, preferably 1-15 μm, the thickness of the retardation layer is, for example, 0.5-200 μm, preferably 1-75 μm. When a hologram layer and a reflective layer are provided, the thickness of the hologram layer is, for example, 0.1-20 micrometers, Preferably it is 1-10 micrometers, and the thickness of a reflection layer can be 0.1-1500 nm, for example, Preferably it is 5-1000 nm.

[Media label for authenticity determination, Media label sheet for authenticity determination]
Furthermore, the present invention relates to an authenticity determination medium label having the authenticity determination medium of the present invention and an adhesive layer on at least one surface of the authenticity 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.

  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. When the authenticity determination medium of the present invention has a hologram layer (or further a reflection layer) as described above, it is preferable to provide a heat-sensitive adhesive layer on the hologram layer side and a base film on the other side. 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, the release layer described above can be used.

  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. 2 shows a specific example of an article having the authenticity determination medium of the present invention so as to be visible.

  FIG. 2 (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 medium 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.

  The one shown in FIG. 2 (b) is the one in which the medium for authenticity determination according to the present invention is built in a sheet-like material in advance so as to be visible, and is 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. For ease of application, the authenticity determination medium is cut into a very narrow width (for example, a vertically long thread shape in FIG. 2B), for example, in the case of paper. 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.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to the aspect shown in an Example.

[ Reference Example 1]
A cholesteric liquid crystal (20% toluene solution) was applied to a PET film (retardation layer), dried and UV cured to form a first light selective reflection layer. A PVA (peeling layer) was applied and dried on the back surface of this film, rubbed, and then a cholesteric liquid crystal (20% toluene solution) different from the above was applied, dried and UV cured to form a second light selective reflection layer. . A hologram resin was applied to the film, hologram processing was performed to form a hologram layer, and transparent deposition was further performed on the hologram layer to form a reflective layer. Observing the true / false judgment medium thus obtained from the first light selective reflection layer side, the color change effect of the cholesteric liquid crystal can be confirmed. When the right circularly polarizing plate is applied, it appears green, and when the left circularly polarizing plate is applied, it is red. Looked like.

[ Reference Example 2]
An alignment film (adhesive layer) was applied to the TAC film and rubbed, and then a nematic liquid crystal was applied to form a retardation layer. A cholesteric liquid crystal (20% toluene solution) was applied thereon, dried and UV cured to form a first light selective reflection layer. A PVA (peeling layer) was applied and dried on the back surface of this film, rubbed, and then a cholesteric liquid crystal (20% toluene solution) different from the above was applied, dried and UV cured to form a second light selective reflection layer. . A hologram resin was applied to the film, hologram processing was performed to form a hologram layer, and transparent deposition was further performed on the hologram layer to form a reflective layer. When the true / false determination medium thus obtained is observed from the first light selective reflection layer side, the color change effect of the cholesteric liquid crystal can be confirmed, and when the right circular polarizing plate is applied, it looks green, and when the left circular polarizing plate is applied. It looked red.

[ Reference Example 3]
An adhesive layer (transparent, black, etc.) was provided on the reflective layer of the authenticity determination medium prepared in Reference Examples 1 and 2, and punching was performed to obtain an authenticity determination medium label.
When the adhesive layer of the label obtained in Reference Example 3 was attached to the article, the label was peeled off when the label was peeled off. The peeled film appeared green when the right circularly polarizing plate was applied, but no reflected light was observed even when the left circularly polarizing plate was applied.

[Comparative example]
A cholesteric liquid crystal (20% toluene solution) was applied to a PET film (retardation layer), dried and UV cured to form a first light selective reflection layer. A cholesteric liquid crystal (20% toluene solution) different from the above was applied to the back surface of this film, dried and UV cured to form a second light selective reflection layer. A release layer and a hologram resin were applied to the second light selective reflection layer side of the film, and hologram processing and transparent vapor deposition were performed.
When the obtained film was observed from the first light selective reflection layer side, the color change effect of the cholesteric liquid crystal could be confirmed, and it looked green when the right circular polarizing plate was applied, and red when the left circular polarizing plate was applied. This film was subjected to adhesive processing and punching to form a label.
When it was going to peel after attaching the obtained label to articles | goods, it peeled in the peeling layer located in the lower layer of a 2nd light selective reflection layer. The peeled film appeared green when the right circular polarizer was applied, and red when the left circular polarizer was applied.

As described above, the authenticity determination medium according to the present invention has the first light selective reflection layer and the second light at the fragile portion (the peeling layer in the above reference example) as a boundary when it is peeled off after being applied to an article. The selective reflection layer is separated. For this reason, since the authenticity determination medium of the present invention cannot be peeled off from a genuine product and reused for a counterfeit product or a falsified product, it is extremely effective in preventing forgery and falsification.

It is sectional drawing which shows an example of the medium for authenticity determination of this invention. The specific example of the article | item which has the authenticity determination medium of this invention visibly is shown.

Claims (9)

A first light selective reflection layer having a light reflecting property that reflects either left circularly polarized light or right circularly polarized light in incident light, a phase difference layer, and either left circularly polarized light or right circularly polarized light in incident light. A medium for authenticity determination having a second light selective reflection layer having light reflectivity for reflecting one side in this order,
It has a fragile portion between the first light selective reflection layer and the second light selective reflection layer, and
The fragile portion may authenticity determination medium characterized Rukoto included in the retardation layer. The authenticity determination medium according to claim 1, wherein the second light selective reflection layer has a center wavelength of reflected light different from a center wavelength of reflected light reflected from the first light selective reflection layer. The retardation layer comprises at least two layers,
The fragile portion is either more any layer included in the retardation layer, or other layer facing the surface of the layers included in the retardation layer, for authenticity determination according to claim 1 or 2 Medium. The true layer according to any one of claims 1 to 3 , further comprising a hologram layer on a surface of the first light selective reflection layer or the second light selective reflection layer opposite to the surface facing the phase difference layer. False judgment medium. The authenticity determination medium according to claim 4 , further comprising a reflection layer on a surface opposite to a surface facing the light selective reflection layer of the hologram layer. A medium label for authenticity determination having an adhesive layer on at least one surface of the authenticity determination medium according to any one of claims 1 to 5 and the authenticity determination medium. A medium transfer sheet for authenticity determination having a base material having a peelable surface and a medium label for authenticity determination according to claim 6 ,
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 the heat-sensitive adhesive layer, the authenticity determination medium 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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