JP2010230785A - Authenticity identification object - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To resolve the problem, wherein the light reflected from a reflective thin film formed on a relief hologram deteriorates the visibility and discrimination of cholesteric liquid crystal and makes it difficult to discriminate an authenticity identification object, having the cholesteric liquid crystal and the relief hologram laminated. <P>SOLUTION: A color pattern layer devised to prevent reflected light on the interface between the relief hologram and the reflective thin film formed on the relief hologram from being strong, as well as, being diffracted to become return light is provided between the relief hologram and the reflective thin film and at a position facing the cholesteric liquid crystal; and thereby the visibility of the cholesteric liquid crystal is improved and the precision of authenticity determination is improved. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an authenticity identifier that makes it possible to distinguish between an object obtained by forgery or falsification based on an unauthorized intention and an authentic object. The present invention also relates to a product in which such an authenticity identifier is processed into a label form or transfer sheet form suitable for application to an article.

  In the present specification, “part” indicating the formulation is based on mass. The “hologram” includes a hologram and a hologram having a light diffractive function such as a diffraction grating.

  (Main use) The main use of the hologram sheet of the present invention is a hologram sheet used in the field of anti-counterfeiting. Specifically, when used as a counterfeit such as a credit card, the card holder That may cause damage to the credit card company, driver's license, employee ID card, membership card, ID card, entrance examination voucher, passport, banknote, gift certificate, point card, stock certificate, securities, lottery ticket There are horse tickets, bankbooks, boarding tickets, pass tickets, air tickets, admission tickets for various events, play tickets, prepaid cards for public transportation and public telephones.

Each of these is an information recording body that holds information having economic or social value, and it is desirable to have a function that can identify the authenticity of the recording body for the purpose of preventing damage caused by forgery. .

In addition to these information recording media, expensive products such as luxury watches, luxury leather products, precious metal products, jewelry, etc., often referred to as luxury brand products, or storage of such expensive products. Boxes and cases can also be forged. In addition, mass-produced products of famous brands, such as audio products, electrical appliances, etc., or tags that are hung on them are also subject to forgery.

Furthermore, a storage body in which music software, video software, computer software, game software, or the like, which is a copyrighted work, or cases thereof can also be forged. In addition, it is desirable that products such as printer toner, paper, and the like in which supplies to be replaced are limited to genuine materials have a function of identifying their authenticity for the purpose of preventing damage caused by forgery.

(Background technology)
Conventionally, for the purpose of preventing forgery of information recording bodies and the above-mentioned various articles (collectively referred to as authenticity identification objects), it is said that they have manufacturing difficulties due to the precision of their structures. Often, holograms are applied as authenticity distinguishable. However, since the hologram manufacturing method itself is known and can be precisely processed by that method, when the hologram is merely for visual judgment, there is no difference between a genuine hologram and a forged hologram. It is difficult to distinguish.

  These authentic identification objects, in particular, articles that have been subjected to hologram images in a label form or transfer form, are not only used for authentic identification of visual confirmation of hologram images, but also by using a new authenticity identification method. There is a need to identify the authenticity of.

(Prior art)
In order to meet these requirements, an authenticity discriminator having a light selective reflection layer that is laminated on a hologram and reflects only one of the left-handed polarized light and the right-handed polarized light in the incident light is proposed. It was. (For example, refer to Patent Document 1.)
As this light selective reflection layer, cholesteric liquid crystal is used, and the anti-counterfeiting property is enhanced by a method of confirming using a polarizing plate or the like.

  However, as described in Patent Document 1, since the reflectance of the reflective thin film layer on the hologram forming layer is high, the light that is transmitted without being reflected by the cholesteric liquid crystal layer (complementary light of selective reflected light) Reflecting on the reflective thin film layer and returning to the cholesteric liquid crystal layer again (hereinafter referred to as return light), this return light becomes a noise component when observing the cholesteric liquid crystal and is added to and mixed with the selectively reflected light. However, the color tone was not the original color of the liquid crystal, and it was even difficult to see and identify.

For this reason, in Patent Document 1, a contrivance is made such that the reflective thin film layer is partially formed or removed, and the liquid crystal layer is visually recognized in a portion that is not formed or removed. In this formation or partial removal method, a thin film is formed through a pattern mask having a shielding portion and an opening, and a thin film is not formed on a substrate in a portion having the shielding portion, or a water-soluble resin pattern is used. Utilizing this method, a reflective thin film layer is formed on the entire surface of the substrate including the water-soluble resin pattern, and only the portion with the water-soluble resin pattern is removed with an aqueous solution, etc., and the reflective thin film layer is patterned. It is shown.

The former places a pattern mask on the substrate, forms a thin film from the pattern mask to the substrate, forms a thin film only at the opening of the pattern mask, and then removes the pattern mask to form a partial thin film. However, there are disadvantages in that not only the pattern mask creation work and its installation / removal work are complicated, but also the pattern position accuracy is insufficient.

In the latter, pattern printing is performed with a water-soluble ink in which a water-soluble resin or a water-swellable resin is dissolved or dispersed in a portion to be removed, and a reflective thin film layer is formed on the entire surface, and then water, acid or alkaline is formed on the surface. The water-soluble resin pattern is removed by contacting with an aqueous solution, and the reflective thin film layer where the water-soluble resin pattern is laminated is removed, thereby reflecting the portion where the water-soluble resin pattern is not laminated. The reflective thin film layer is formed in a pattern while leaving the conductive thin film layer, and the operation is very complicated.

  Furthermore, there is a method for absorbing a part of the complementary color light and improving the degree of freedom in design by providing an adhesive layer containing a coloring dye or a coloring pigment in the portion from which the reflective thin film layer has been removed. Although it has been proposed, only a part of the complementary color light is absorbed, and the complementary color light causes interfacial reflection at the interface between the transparent resin layer and the pressure-sensitive adhesive layer, resulting in a design effect such as a combination of a colored layer and a liquid crystal layer. Has the disadvantage that it cannot be fully extracted.

JP 2007-90538 A

  Accordingly, the present invention has been made to solve such problems. The purpose is to create an authentic discriminator that is less discriminative in the discriminability of the cholesteric liquid crystal layer due to the lamination of the cholesteric liquid crystal layer and the hologram forming layer, can sufficiently bring out the combination effect with the colored layer, and can easily identify the authenticity. Is to provide.

To solve the above problem,
The first aspect of the authenticity identifier of the present invention is:
A cholesteric liquid crystal layer is provided on at least a part of one surface of the transparent substrate, a transparent resin layer having a hologram relief on the other surface of the transparent substrate, and a part on the hologram relief, A reflective thin film is provided so that a colored pattern layer having a refractive index difference of 0.05 or more with respect to the transparent resin layer is provided at least at a position facing the cholesteric liquid crystal layer, and follows the colored pattern layer and the hologram relief. A layer is provided.

According to the authenticity identifier of the first aspect,
A colored pattern layer having a refractive index difference of 0.05 or more from the hologram forming layer is provided between the transparent resin layer having the hologram relief and the reflective thin film layer, at least at a position facing the cholesteric liquid crystal layer. Therefore, of the light (observation light) incident on the cholesteric liquid crystal for observation, the predetermined light is first reflected by this liquid crystal layer (selective reflected light), and other light (complementary color of reflected light and Is transmitted through the liquid crystal layer, reaches the reflective thin film layer, and is reflected by this layer. In the portion where the colored pattern layer is provided, the colored pattern layer This complementary color light is absorbed over a predetermined wavelength range (meaning an absorption wavelength determined by a color pigment or dye), and hologram diffracted light having a characteristic color tone (reproducing a hologram) ) As is reflected. Therefore, this hologram reproduction image has its characteristic color tone.

The light reflected by the reflective thin film layer usually reproduces a hologram reproduction image by the observed light (meaning no change in color tone).
Since the image formation positions of these hologram reproduction images are completely overlapped, a color tone in which the “characteristic color tone” and the color tone of the observation light are mixed is obtained.
Accordingly, the color tone is uniquely determined by the color tone of the colored pattern and the closing ratio (area ratio between the reflective thin film layer and the colored pattern).
Furthermore, the reflective thin film layer also exhibits a color tone that depends on the material of the thin film layer, such as a metal or a metal compound (for example, aluminum that is a full-wavelength reflection type that looks visually white to grayish white) The reflection intensity has wavelength dependency and is not reflected uniformly with respect to all wavelengths.) Therefore, the reflection intensity is reflected by partial absorption of light by the constituent metal or metal oxide. The color of light changes.
The reproduced hologram image has a unique color tone by overlapping these color tones.
Interfacial reflection at the interface between the transparent resin layer having a hologram relief and the colored pattern layer occurs when there is a difference in the refractive index of the layer in contact (even with a difference of 0.01), and becomes stronger as the refractive index difference increases. Reflects (differs fairly strongly at a difference of 0.05 or more). The intensity of this reflection varies depending on the wavelength of incident light and the incident angle as light to be observed.

In order for the hologram reproduction image from the colored pattern portion and the hologram reproduction image from the reflective layer thin film layer portion to overlap with each other as a hologram image with high accuracy (meaning that there is little optical distortion, blur, etc.) It is desirable that the light is reflected in a substantially dotted manner so that reflected light (also referred to as diffracted light) is emitted almost uniformly from any part of the hologram relief, and the pattern covering the hologram relief and the area ratio of closing each are uniform.
Of course, theoretically, due to the "hologram (relief) redundancy", even if the observation light is applied to a small part of the hologram (relief), a normal hologram relief should be reproduced. This level is not sufficient for use, and the above-mentioned consideration is necessary because the determination ease when the reproduced image is visually confirmed and high determination accuracy are obtained. .
Synthetic inorganic pigments: white pigments (zinc white), natural inorganic pigments: brown pigments such as amber and senna, calcium carbonate, kaolin, pearl pigments (which exhibit a unique and tasty color when combined with cholesteric colors), etc. , Lead white, titanium dioxide), red pigment (red lead, iron oxide red), yellow pigment (yellow lead, chrome yellow, zinc yellow), blue pigment (ultramarine blue, prussian blue), ceramic pigment or azo Pigments, polycyclic pigments: quinancridon, perinone, quinophthalone, phthalocyanine, indanthrene, quinacridone, etc. Lake pigments: Lake Red C, Wootung Red, etc., natural dyes: Akane, Eye, Turmeric, etc. Synthetic dyes : Alizanin, indigo, etc. are used, but the resin layer of the colored pattern containing these pigments and dyes has interface reflection. To Ku, the difference between the refractive index of the transparent resin layer is 0.05 or more, preferably, to use a 0.2 or higher.

Since the refractive index difference between the transparent resin having a hologram relief and the resin constituting the colored pattern has an upper limit as long as it is a resin, the refractive index difference is limited to 0.5. Of course, when an inorganic material having a high refractive index is mixed, the “refractive index of the resin layer” is apparently high, but the interface reflection in the present invention is directly applied to the transparent resin layer having a hologram relief and the relief. There is an upper limit because the reflection is at the interface with the resin surface that is in contact (a material with a high refractive index mixed as a filler is not in contact because there is a slight distance from the interface). Since the depth of the hologram relief itself is only about 0.1 μm, the properties of the resin contributing to the interface reflection here are also almost determined on the interface.
When the material of the reflective thin film is a metal, it has a “complex refractive index” (refers to the refractive index of the metal and has high reflectivity at the interface with the resin layer) and is reflective. high. Moreover, the metal oxide etc. used as a transparent reflective thin film also have a high refractive index. Therefore, in order to balance the colored pattern, it can be controlled by adjusting the area ratio of the reflective thin film and the colored pattern layer.

That is, it controls the interface reflection between the transparent resin layer having a hologram relief, the reflective thin film layer and the colored pattern layer, and has a unique color tone that is reproduced at a different angle when observing the cholesteric liquid crystal. The hologram reproduction image can be made more characteristic, and anti-counterfeiting and design properties are expected to be improved.
As the transparent resin layer having the hologram relief, a thermoplastic resin such as an acrylic resin or a thermosetting resin such as an epoxy-modified unsaturated polyester resin resin is used. Therefore, the resin used for the colored pattern layer is more refracted. It is desirable to use a high-rate melamine or epoxy resin.

  The pigment particle size is usually about 0.01-5 μm, desirably 0.1 μm-0.5 μm, and is added to the above resin by about 10-50% and used after sufficiently dispersing. For the purpose of improving the property and making the side of the colored pattern forming surface in contact with the thin film a rough surface, one having a thickness of 1 μm to 5 μm can also be used.

The formation method of the colored pattern layer is not required to use a complicated operation such as partial removal of the thin film described above, and an appropriate method can be used for the formation pattern such as an offset printing method, a gravure printing method, a screen printing, or the like. .
However, in order to form a fine pattern such as a halftone dot having a size of several tens of μm to several mm, a stainless screen printing method that has high printing position accuracy and does not cause bleeding of the printing pattern is desirable.
In addition, when the position is aligned with the formation pattern of the cholesteric liquid crystal layer (when synchronized), it is desirable to use the same formation method as that of the cholesteric liquid crystal layer. Furthermore, a flexographic printing method can be used in order to make the formation thickness relatively thick and suppress bleeding and ink sag. The thickness to be formed is adjusted according to the characteristics of the pigment / dye used and the amount added, but is usually about 2 to 20 μm.

Further, the second aspect of the authenticity identifier of the present invention is:
In the first half hologram relief, the portion of the hologram pattern in contact with the colored pattern layer is different from the portion of the hologram pattern in contact with the reflective thin film layer.
According to the authenticity identifier of the second aspect,
In the initial hologram relief, an authenticator can be provided in which the hologram pattern is different between the portion in contact with the colored pattern layer and the portion in contact with the reflective thin film layer.
That is, the imaging position of the hologram image reproduced from the colored pattern layer portion and the hologram image reproduced from the reflective thin film layer portion and the content of the reproduced image are different.
This is achieved by forming two holograms in a predetermined pattern at the time of hologram relief formation, forming a colored pattern according to this distribution, and then forming a reflective thin film layer on the entire surface including the colored pattern. can do.
In this way, in addition to the selectively reflected light of the cholesteric liquid crystal, it is possible to observe a holo-hologram image that is imaged at a predetermined direction position and a colored hologram image that is imaged at another predetermined position. The prevention is improved.
Further, by making the holograms corresponding to the respective parts different, it is possible to set without adjusting the difference in the reflected light intensity.
Further, when the surface of the reflective thin film layer that contacts the colored pattern layer is a rough surface, among the complementary color light, the light that has been transmitted without being absorbed by the colored pattern layer is scattered without being totally reflected by the reflective thin film layer surface. be able to. This can reduce noise and, as a result, improve visibility. The rough surface means that the cross-sectional shape is irregular irregularities, and thus the light reflected by the surface becomes scattered light.

As a method of roughening the colored pattern layer, a method of roughening using a coloring pattern forming method and a method of increasing the pigment size to be used may cause the pigment to push up or jump out of the surface of the colored pattern layer. There is a method to roughen the surface. As a method using the forming method, there is a method of performing embossing having a rough surface pattern after pattern formation or roughening a mesh used in silk screen printing. As a method for enlarging the pigment size, if the size of the pigment / dye or other extender pigment is set to be about the thickness of the colored pattern layer, the pigment protrudes from the formation surface after forming the colored pattern, resulting in a rough surface.
In any embodiment, the constituent order of the layers may be a transparent base material, a cholesteric liquid crystal, a hologram forming layer, and a reflective thin film layer.

  According to the authenticity identifier of the present invention, there is little deterioration in the discriminability of the cholesteric liquid crystal layer due to the lamination of the cholesteric liquid crystal layer and the hologram forming layer, the design is improved, and the authenticity can be easily identified visually. An authenticity identifier is provided.

It is sectional drawing of the authenticity identification body A which shows one Example of this invention. It is sectional drawing of authenticity identification body A 'which shows the other Example of this invention.

  (Transparent Substrate) The transparent substrate 1 used in the present invention can be reduced in thickness, and can withstand mechanical strength and processing when manufacturing authenticity identifiers A and A ′. Those having solvent resistance and heat resistance are preferred. Since it depends on the purpose of use, it is not limited, but 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. .
The thickness of the transparent substrate 1 is usually 5 to 250 μm, but when considering the sneak light from the reflective thin film layer 3, it is preferably 5 to 50 μm, particularly 5 to 25 μm.

  (Transparent resin layer having hologram relief: also referred to as hologram forming layer) As the transparent resin material for constituting the hologram forming layer 2 of the present invention, various thermoplastic resins, thermosetting resins, or ionizing radiation curing are used. Can be used. Thermoplastic resins include acrylic ester resins, acrylamide resins, nitrocellulose resins, or polystyrene resins. Thermosetting resins include unsaturated polyester resins, acrylic urethane resins, epoxy-modified acrylic resins, and epoxy-modified unsaturated resins. A polyester resin, an alkyd resin, a phenol resin, etc. are mentioned.

These thermoplastic resins and thermosetting resins can be used alone or in combination of two or more. One or more of these resins may be cross-linked using various isocyanate resins, or various curing catalysts, for example, metal soap such as cobalt naphthenate or zinc naphthenate may be blended. Or peroxide such as benzoyl peroxide and methyl ethyl ketone peroxide for initiating polymerization with heat or ultraviolet light, benzophenone, acetophenone, anthraquinone, naphthoquinone, azobisisobutyronitrile, or diphenyl sulfide good.

Examples of the ionizing radiation curable resin include epoxy acrylate, urethane acrylate, acrylic-modified polyester, etc., for the purpose of introducing a crosslinked structure into such an ionizing radiation curable resin or adjusting the viscosity, A monofunctional monomer, a polyfunctional monomer, or an oligomer may be blended and used.

In order to form the hologram forming layer 2 using the above resin material, it can be directly formed by developing the photosensitive resin material by performing interference exposure of the hologram. It is preferable to perform molding by using a replica or a plating mold thereof as a replica mold and pressing the mold surface against the layer of the resin material.

When thermosetting resin or ionizing radiation curable resin is used, curing is performed by heating or ionizing radiation irradiation while keeping the uncured resin in close contact with the mold surface, and then cured by peeling after curing. The fine irregularities of the relief hologram can be formed on one side of the layer made of a transparent resin material. A diffraction grating forming layer having a diffraction grating formed in a pattern by a similar method can also be used as the optical diffraction structure.

  A hologram is a recording of interference fringes due to interference of light between object light and reference light in an uneven relief shape. For example, a laser reproduction hologram such as a Fresnel hologram, a white light reproduction hologram such as a rainbow hologram, There are color holograms utilizing the above principle, computer generated holograms (CGH), holographic diffraction gratings and the like. Further, like a machine readable hologram, the reproduction light may be converted into data by a light receiving unit and transmitted as predetermined information, or authenticity determination may be performed.

In order to precisely create fine irregularities, not only optical methods, but also electron beam lithography equipment can be used to create precisely designed relief structures that produce more precise and complex reproduction light. Good. The relief shape is designed to have a pitch, depth, or specific periodic shape of the unevenness according to the wavelength (range) of the light or light source for reproducing or reproducing the hologram, the direction and the intensity of reproduction or reproduction. The pitch (period) of the unevenness depends on the reproduction or reproduction angle, but is usually 0.1 μm to several μm, and the depth of the unevenness is a factor that greatly affects the reproduction or reproduction intensity, but is usually 0.1 μm. ˜1 μm.

As in the case of a single diffraction grating, when the unevenness of exactly the same shape is repeated, the more the adjacent unevenness is the same, the greater the intensity of interference of the reflected light and the stronger the intensity. Converge. The blur in the diffraction direction is also minimized. When the individual points of the image converge to the focal point, such as a stereoscopic image, the convergence accuracy to the focal point is improved, and the reproduced or reproduced image becomes clear.
Furthermore, in the case of a transparent metal compound thin film, the upper and lower surfaces of the thin film have the same relief shape, and the more uniform the distance between the surfaces (that is, the film thickness), the higher the reproduction or reproduction strength. growing.

  The hologram relief shape is shaped (also referred to as replication) by using an original plate on which diffraction gratings and interference fringes are recorded in a concavo-convex shape as a press die (referred to as a stamper), and the transparent substrate 1 and the reflective thin film layer 3. The uneven pattern of the original plate can be duplicated by superimposing the original plate on top of each other and heat-pressing both of them with an appropriate means such as a heating roll. The hologram pattern to be formed may be single or plural.

In order to accurately reproduce the above-mentioned extremely fine shape and to minimize distortion and deformation such as heat shrinkage after replication, the original plate is made of metal and replicated at low temperature and high pressure.
For the original plate, a metal having high hardness such as Ni is used. After a Cr or Ni thin film layer is formed on the surface of a glass master or the like formed by optical imaging or electron beam drawing or the like by vacuum deposition or sputtering, Ni or the like is electrodeposited (electroplating, electroless plating) Further, it can be made by peeling the metal after forming 50 to 1000 μm by composite plating or the like.
The duplication method uses a flat plate type or a rotary type, the linear pressure is 0.1 ton / m to 10 ton / m, and the duplication temperature is usually 60 ° C. to 200 ° C.

(Reflective thin film layer) In the present invention, the reflective thin film layer 3 is formed on the hologram relief surface of the hologram forming layer 2. Since this thin film layer needs to reflect incident light, it is not particularly limited as long as it is a thin film layer having a higher refractive index than that of the hologram forming layer 2.
The reflective thin film layer 3 may be either a metallic glossy reflective layer such as a metal thin film formed by a vacuum thin film method or the like, or a transparent reflective layer. When provided, it is preferable because the design of the authenticity identification object can be confirmed through the transparent reflective layer.
As a transparent reflective layer, since the optical refractive index is different from that of the hologram forming layer 2 with a substantially colorless and transparent hue, it is possible to visually recognize the glitter of a hologram or the like even though there is no metallic luster, A transparent hologram can be produced. For example, a thin film having a higher refractive index than that of the hologram forming layer 2, such as ZnS, TiO ₂ , Al ₂ O ₃ , Sb ₂ S ₃ , SiO, SnO ₂ , ITO, and the like are available.

Preferably, it is a metal oxide or nitride, specifically, Be, Mg, Ca, Cr, Mn, Cu, Ag, Al, Sn, In, Te, Ti, Fe, Co, Zn, Ge, Pb. Cd, Bi, Se, Ga, Rb, Sb, Pb, Ni, Sr, Ba, La, Ce, Au, and other oxides or nitrides, and the like can be exemplified by a mixture of two or more thereof. Also, a general light-reflective metal thin film such as aluminum can be used as a transparent reflective layer when it has a thickness of 20 nm or less and becomes transparent.
The transparent metal compound is formed on the hologram relief surface of the hologram forming layer 2 by vapor deposition, sputtering, ion plating, CVD (to the thickness of about 10 to 2000 nm, preferably 20 to 1000 nm, similarly to the metal thin film. It may be provided by a vacuum thin film method such as a chemical vapor deposition method.

(Cholesteric Liquid Crystal) The cholesteric liquid crystal layer 4 used in the present invention is only required to have light selective reflectivity, and further, either left circularly polarized light or right circularly polarized light is applied to incident light from the observation side. It may have light selective reflectivity to reflect. Also, by applying these in combination, the determination method can be complicated, and a more sophisticated authenticity identifier can be obtained.
Cholesteric liquid crystals include cholesterol halides, monocarboxylic acid cholesterol esters, monocarboxylic acid sitosterol esters, benzoic acid derivative cholestanol esters, dibasic acid dicholesteryl esters, main chain liquid crystal polymer compounds, side chain liquid crystal polymers Examples thereof include molecular compounds and rigid main chain type liquid crystal polymer compounds.

  More specifically, for example, cholesteryl chloride, cholesteryl acetate, cholesteryl nonanoate, methyl carbonate, ethyl cholesterol, cholesteryl p-methoxybenzoate, sitosteroyl benzoate, sitosteroyl p-methyl benzoate, cholestanyl benzoate, 10, 12- Docosadiin dicarboxylic acid dicholesteryl ester, 8,12-eicosadicarboxylic acid dicholesteryl ester, 10,12-pentacosadiin dicarboxylic acid dicholesteryl ester, dodecadicarboxylic acid dicholesteryl ester, 12,14-hexacosadiin dicarboxylic acid Dicholesteryl ester, 4- (7-cholesteryloxycarbonylheptyloxy) phenoxyoctanoic acid cholesteryl ester, L-glu Min acid -γ- benzyl / L-glutamate -γ- dodecyl copolymers and the like.

  Further, cholesteryl formate, cholesteryl acetate, cholesteryl propionate, cholesteryl butyrate, cholesteryl pentanate, cholesteryl hexanate, cholesteryl heptanoate, cholesteryl octanate, cholesteryl nonanoate, cholesteryl decanate, cholesteryl decanate (cholesteryl laurate) Cholesteryl myristate, cholesteryl palmitate, cholesteryl stearate, cholesteryl oleate, cholesteryl oleyl carbonate, cholesteryl linoleate, cholesteryl 12-hydroxystearate, cholesteryl mercaptan, cholesterol chloride, cholesteryl fluoride, cholesteryl bromide, cholesteryl iodide, etc. Can be mentioned.

Preferably, a mixture of three kinds of alkylcholesterol (for example, cholesterol nanoate) and cholesteryl halide (for example, cholesterol chloride) cholesteryl oleyl carbonate is used, and these three types of liquid crystals are used so as to be used at room temperature. Is common.
In addition, it is not limited to the compound shown here, Moreover, these cholesteric liquid crystal compounds can be used 1 type or in mixture of 2 or more types.
As a liquid crystal compound in which a chiral compound is added to a nematic liquid crystal compound, 4-substituted benzoic acid 4′-substituted phenyl ester, 4-substituted cyclohexanecarboxylic acid 4′-substituted phenyl ester, 4-substituted cyclohexane Carboxylic acid 4′-substituted biphenyl ester, 4- (4-substituted cyclohexanecarbonyloxy) benzoic acid 4′-substituted phenyl ester, 4- (4-substituted cyclohexyl) benzoic acid 4′-substituted phenyl ester, 4- (4- Substituted cyclohexyl) benzoic acid 4'-substituted cyclohexyl ester, 4-substituted 4'-substituted biphenyl, 4-substituted phenyl 4'-substituted cyclohexane, 4'-substituted cyclohexane, 2- (4-substituted phenyl) -5-substituted pyridine For example, “Palio Color LC242” (manufactured by BASF And the like can be used.

Particularly preferably, a liquid crystal compound having a cyano group or a fluorine atom at least at one end of the molecule is used, and various suitable chiral agents are added to these liquid crystal compounds. As the chiral compound, “CB-15”, “C-15” (manufactured by BDH), “CM-21”, “CM-22”, “CM-19”, “CM-20”, “CM” (Above, manufactured by Chisso Corporation), "S1082", "S-811", "R-811" (above, manufactured by Merck), "Palio Color LC756" (produced by BASF), and the like.
Further, a cholesteric liquid crystal having no cholesterol group in which a group having an asymmetric carbon is introduced into a terminal group of a nematic liquid crystal obtained by organic synthesis, or a mixed liquid crystal in which a Schiff nematic liquid crystal is added to a cholesterol derivative is also used. Furthermore, halogen substitution products and esterified products of natural cholesterol (cholesteryl benzoate, cholesteryl chloride, cholesteryl oleate, cholesteryl nonanoate, and the like are also suitable.

As a method for providing these cholesteric liquid crystals, they can be formed using a normal printing method or coating method as a solvent-based, water-based, or solvent-free system. More preferably, the synchronism of the formation position can be enhanced by using the same means as the colored pattern layer forming method. When the same pattern is formed, the plate making method can be the same. In particular, after the colored pattern layer is provided on the transparent substrate, this position can be used as a timing mark (print positioning mark) to form a liquid crystal layer or to reproduce a hologram relief.
Alternatively, the liquid crystal may be formed using an ink encapsulated with a resin film such as gelatin. The encapsulated product has excellent physical properties (toughness, wear resistance, heat resistance, etc.) as well as workability at the time of manufacture, and prevents problems such as liquid seepage, and is used in the present invention. It is particularly suitable for the required hygiene.

The shape and thickness of the cholesteric liquid crystal layer 4 need to be appropriately optimized according to the purpose of use of the authenticity identifier. Furthermore, since it can be set to several tens of μm as a hidden character like a micro character, the thickness corresponding to each individual, that is, from several μm to 50 μm, while maintaining selective reflectivity, It shall be optimal.
When the cholesteric liquid crystal layer 4 is provided, an alignment treatment such as providing the following alignment film may be performed in advance. 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 is formed by applying a solvent solution of these resins to the surface of the layer forming the cholesteric liquid crystal layer 4 by an appropriate application method and drying, followed by rubbing with a cloth, a brush, or the like. To do.

(Colored pattern layer)
In the present invention, the colored pattern layer 5 is formed on the hologram relief surface of the hologram forming layer 2 at a position at least facing the cholesteric liquid crystal layer 4.
In order to generate interface reflection between the hologram forming layer 2 and the colored pattern layer 5, a resin layer constituting the hologram forming layer 2 and the colored pattern layer 5 having a refractive index difference of 0.05 or more is used. More preferably, it is 0.20 or more.

  That is, polymethyl methacrylate (refractive index n = 1.50), polybenzyl methacrylate (n = 1.57), cellulose nitrate (n = 1.54), methyl cellulose (n = 1.50), polystyrene (n = 1) .60), polyethylene terephthalate (n = 1.64), polyvinyl chloride / vinyl acetate (n = 1.54), melamine resin (n = 1.56), epoxy resin (n = 1.61), phenol resin (N = 1.60) or a mixture thereof can be used as appropriate.

  As the coloring pigment, any of the above-mentioned pigments and dyes having absorptivity with respect to a predetermined wavelength region of light to be observed (visible light) can be used. From the refractive index, calcium carbonate (n = 1.58) , Barium carbonate (n = 1.6), mica (n = 1.58), ultramarine (n = 1.57), bitumen (n = 1.56) silicon compound system (n = 1.45 to 1.60) Those having a high refractive index such as) are preferred.

A particle size of 0.01 to 0.1 μm is preferable, but secondary aggregation tends to occur, and redispersion treatment or the like needs to be performed. The addition amount is determined by the balance with the thickness formed by an appropriate formation pattern formation method such as an offset printing method, a gravure printing method, etc., but usually 10% to 50% addition is preferable, dissolved in an appropriate solvent, It is formed to a thickness of 2 to 20 μm.
Since the dye has little influence on the refractive index of the resin to be used, a dye having excellent dispersibility and solubility with the resin to be used can be used.
After the coloring pattern is formed, the surface of the coloring pattern can be roughened by heating and pressing with a metal stamper having irregularities with a surface roughness of 1.0 μm or more. In addition to this colored pigment, the colored pattern layer can also be roughened by using extender pigments such as calcium carbonate and titanium dioxide having a particle size of 1.0 μm or more. This roughening scatters excess light that has also passed through the colored pattern.

Further, the authenticity identification body of the present invention can be further labeled with a pressure-sensitive adhesive or a transfer sheet by applying an adhesive.
In this case, as the pressure-sensitive adhesive, any conventionally known solvent-based or water-based pressure-sensitive adhesives such as vinyl acetate resin, acrylic resin, vinyl acetate-acrylic copolymer, vinyl acetate-vinyl chloride copolymer, ethylene-acetic acid are used. Examples include vinyl copolymers, polyurethane resins, and rubber resins such as natural rubber and chloroprene rubber.
Natural latex such as natural rubber latex, natural rubber latex obtained by graft polymerization of natural rubber with styrene, especially methacrylic acid methyl, in particular, to make natural material composition What was produced from the raw material may be used and formation thickness, a formation method, etc. are selected suitably.

Moreover, as an adhesive agent, since it is for ensuring the adhesiveness with respect to various articles | goods, what has good adhesiveness with the reflective thin film layer 4, and can adhere | attach an adherend firmly. preferable. Specific examples include vinyl chloride resins, vinyl acetate resins, vinyl chloride-vinyl acetate copolymer resins, acrylic resins, polyester resins, polyurethane resins, polyamide resins, and rubber-modified products. Appropriately selected from the above can be used, and these can be used alone or in a mixture of two or more, and if necessary, hard resin, plasticizer, and other additives can be added and used. The formation thickness, the formation method, and the like are appropriately selected.

Example 1
As a transparent substrate 1, a cholestic liquid crystal layer 4 having a thickness of 5 μm was formed on the surface of a 25 μm PET film by gravure printing into a “mark of 20 mm height” mark, and then cured with ultraviolet rays.
・ <Cholesteric liquid crystal composition>
Bicolor LC242 37 parts by weight Bicolor LC756 2 parts by weight UV polymerization initiator 1 part by weight Toluene 60 parts by weight

By applying an acrylic resin (n = 1.44) to the surface opposite to the surface on which the above-mentioned printing of the PET film is performed, the mold surface of the relief hologram duplication mold is heated and cured while being in contact, A relief hologram was formed to obtain a hologram forming layer 2 having a thickness of 20 μm. On top of that, the colored pattern layer 4 having the following composition is formed using the above gravure method and the same gravure plate, and the colored pattern layer 4 having a thickness of 5 μm (a monochromatic pattern having a height of 1 mm. A thin film portion 2 was obtained.
・ <Coloring pattern composition>
The above melamine resin resin composition (n = 1.56) 30 parts by weight Ultramarine 10 parts by weight extender pigment 5 parts by weight toluene 55 parts by weight

On the surface on which the relief hologram is shaped and on the surface of the colored pattern layer 4, AL is vacuum-deposited to form the reflective thin film layer 3 having a thickness of 100 nm.
When the obtained authenticity identifier is viewed from the observation side, the seven colored liquid crystals of the ☆ mark can be seen, and by changing the observation angle, it is possible to recognize a blue hologram reproduction image that is slightly lighter in color than the colored layer. The authenticity was easily determined.

(Example 2)
Example 2 was obtained in the same manner as in Example 1 except that two types of relief holograms were arranged in a pine pattern and the colored pattern was tuned so as to cover the one type of hologram portion. However, the proportion of the pine pattern is the same. When the obtained authenticity identifier is viewed from the observation side, the seven colored liquid crystals of the ☆ mark can be seen. When the viewing angle is changed, the reproduced hologram image has the same color as the colored layer and is reflective at a different angle. Another hologram having a color tone similar to that of the thin film could be recognized, and the authenticity could be easily determined with high accuracy by visual inspection.

(Comparative example)
A comparative example was obtained in the same manner as in Example 1 except that a melamine resin (n = 1.56) was used for the hologram forming layer 2 and the same resin was used for the colored pattern layer 5. When the obtained authenticity identifier is viewed from the observation side, the seven colored liquid crystals marked with a ☆ mark can be seen. If the angle of observation is changed, only one type of reflective thin film and similar color hologram reproduction image can be recognized. In addition, the reflected light from the reflective thin film and the reflected light returning after passing through the colored pattern were conspicuous, and the liquid crystal appearance was insufficient, which was judged to be insufficient for authenticity confirmation.

A, A ′ Authenticity discriminator 1 Transparent substrate 2 Transparent resin layer having hologram relief (hologram forming layer)
3 reflective thin film layer 4 cholesteric liquid crystal layer 5 colored pattern layer

Claims (2)

  A cholesteric liquid crystal layer is provided on at least a part of one surface of the transparent substrate, a transparent resin layer having a hologram relief on the other surface of the transparent substrate, and a part on the hologram relief, A reflective thin film is provided so that a colored pattern layer having a refractive index difference of 0.05 or more with respect to the transparent resin layer is provided at least at a position facing the cholesteric liquid crystal layer, and follows the colored pattern layer and the hologram relief. An authenticity identifier provided with a layer.   2. The authenticity identification body according to claim 1, wherein the hologram pattern of the portion in contact with the colored pattern layer is different from the portion of the hologram pattern in contact with the reflective thin film layer in the initial hologram relief.

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