JP2013095127A - Medium for preventing recording information forgery and information recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a medium which differs in appearance from a conventional cholesteric medium, has a color shift effect and a circularly polarized light reflection characteristic which are unique to cholesteric materials, and allows a specific pattern to be formed thereon at low cost; and to provide a method for forming the specific pattern.SOLUTION: A medium for preventing forgery of recording information which includes at least a color shift information recording layer containing a first cholesteric layer, a black-ink absorbing layer, and a metallic reflective layer.

Description

  The present invention relates to an information recording / forgery prevention medium used for various articles and an information recording method for the medium.

  Anti-counterfeiting technology is used for various articles. For example, a bank note, a bond, a gift certificate, a check such as a check, or a securities. It is also used for various certificates such as credit cards, ID cards, official documents, and important documents. In recent years, it has been applied to various products and their packaging materials to ensure that the products are authentic. Needless to say, if these articles are inspected and proper anti-counterfeiting measures are taken, they are judged as genuine articles, and if no anti-counterfeiting measures are taken or improper measures are not accepted. It is determined as an authentic article.

  Such anti-counterfeiting means is generally divided into an overt technique and a covert technique.

  Overt technology is a technology that anyone can recognize as anti-counterfeiting technology and enable authenticity determination. For example, a diffractive structure such as a hologram observes a phenomenon known as a so-called cholesteric color in which the color or pattern changes depending on the viewing angle, or the color changes depending on the viewing angle due to the effect of the spiral structure of the cholesteric liquid crystal. The method of doing etc. can be illustrated.

  In the method shown in Patent Document 1, both of these diffractive structures and a cholesteric color using a cholesteric and absorbing layer are provided. Such a thing cannot reproduce the phenomenon by simple printing or color copying, and anyone can recognize its existence without requiring a special detector or skilled ability for authenticity determination. For this reason, for example, when a general consumer purchases a product, it can be determined whether or not the product is genuine.

  On the other hand, since its existence is obvious for a malicious person, it is easy to be targeted for forgery or forgery. For example, many forgeries have already been forged due to the improvement of technical capabilities of counterfeiting groups, and there are many products that can achieve similar color and pattern changes despite being poor products. In addition, a film close to a cholesteric color whose color changes depending on the viewing angle can be easily realized by a multilayer film used for high-grade packaging. By combining these, it is possible to create something similar in appearance.

  The covert technique is a technique in which the presence itself cannot be recognized unless there is a special detector or skill. For example, the effect of changing the appearance can be exemplified by layering a special filter. Since the cholesteric liquid crystal described above has a circularly polarized light due to its spiral structure, when the cholesteric liquid crystal reflects a right-handed circularly polarized light, the right-handed circularly polarized light is shielded and a left-handed circularly polarized light is transmitted. When such circularly polarizing filters are stacked, the cholesteric liquid crystal appears black, and when a circularly polarizing filter that transmits right-handed circularly polarized light and shields left-handed circularly polarized light is stacked, a conventional cholesteric color can be observed. As a result, the multilayer film described above does not have the ability to reflect such circularly polarized light, so that even if the multilayer film is forged to resemble a cholesteric color, the counterfeit product can be identified by the filter. is there. In addition, since humans cannot recognize polarized light, it is difficult to recognize that such a discrimination method using a filter exists.

  In addition, as an anti-counterfeiting method, it is proved that the product is genuine by using an old-fashioned method of printing a unique serial number on the product or using a machine reading code typified by a bar code to check against the database. There are techniques to do this.

  In the method disclosed in Patent Document 2, forgery prevention is implemented by embedding a digital watermark in an image.

  From the above, it is preferable that the forgery prevention medium has a mechanism capable of individually assigning a pattern such as a serial number and a digital watermark in addition to the above-described overt technique and covert technique.

  In addition, such media are often used in designs that allow the manufacturer's logo or product name to be recognized by the user, and have a high degree of freedom in design and design. Is preferred.

Japanese Patent No. 4778445 Japanese Patent Laid-Open No. 10-308870

  Among the background technologies described so far, cholesteric is a very useful anti-counterfeiting technology. As described above, not only has both the overt technology that changes color depending on the viewing angle and the covert technology that can discriminate the reflection of circularly polarized light by overlapping circularly polarizing filters, but cholesteric has many color shifting materials. Among them, the color change is particularly large, the appearance is vivid, and the design is excellent, but as mentioned above, it is possible to make the same appearance by using the multilayer film There is.

  In addition, as a method in which this cholesteric has information, in the invention shown in the above-mentioned Patent Document 1, there is a method of using a hologram image as a serial number, and this is to give a unique number to all small pieces of media. Has the problem of being too expensive and unsuitable.

  Therefore, in the present invention, it is difficult to produce a medium that looks like the above, and has a color shift effect and a circularly polarized light reflection characteristic peculiar to cholesteric, and can form an individual pattern at a low cost. An object is to provide a method of forming an individual pattern.

  That is, the invention described in claim 1 is the one showing the minimum configuration of the present invention, and is provided with a color shift information recording layer including at least a first cholesteric layer, a sumi absorption layer, and a metal reflection layer. An information recording forgery prevention medium characterized by the above.

  The invention according to claim 2 is one of the embodiments of the present invention, and in the information recording forgery preventing medium according to claim 1, the surface of the color shift information recording layer in contact with the metal reflective layer, and the variable color layer Is an information recording forgery prevention medium characterized by being provided so as to be in contact with each other.

  Invention of Claim 3 is one of the forms of this invention, and a variable color layer consists of at least a 2nd cholesteric layer and a black absorption layer, and it is provided so that a metal reflective layer and a 2nd cholesteric layer may contact | connect. This is an information recording forgery prevention medium characterized by the above.

  The invention described in claim 4 explains the characteristics of the first cholesteric layer and the second cholesteric layer in the configuration of the information recording forgery preventing medium described in claim 3, and the first cholesteric layer and the second cholesteric layer. The anti-counterfeit medium is characterized in that the first cholesteric layer of the circularly polarized light reflected from the light is left-handed polarized light or right-handed polarized light, and the second cholesteric layer is circularly polarized light opposite to the first cholesteric layer. .

  The invention according to claim 5 is characterized in that the color change of the first cholesteric layer and the second cholesteric layer in the information recording forgery prevention medium according to claim 3 or claim 4 is exactly the same. Information recording counterfeit prevention medium.

  The invention according to claim 6 is the information recording characterized in that the color change of the first cholesteric layer and the second cholesteric layer in the information recording forgery prevention medium according to claim 3 or 4 is different. It is an anti-counterfeit medium.

  The invention described in claim 7 is one of the forms for utilizing the information recording forgery preventing medium described in claims 1 to 6 and is opposite to the provision of the first cholesteric layer. The information recording counterfeit prevention sticker is characterized in that an adhesive layer is provided on the surface.

  The invention described in claim 8 is an embodiment of the present invention, and is an anti-counterfeit article in which the information recording anti-counterfeit sticker described in claim 7 is attached to the article.

  The invention according to claim 9 is one of the forms for utilizing the information recording forgery preventing medium according to claims 1 to 6, and the information recording forgery according to claims 1 to 6. In the prevention medium, an information recording forgery prevention transfer foil in which a support that can be separated by separation is provided so as to be in contact with the first cholesteric layer, and an adhesive is provided on a surface opposite to the support, It is an anti-counterfeit article formed by attaching to and peeling off the support.

  The invention according to claim 10 is one of the forms for utilizing the information recording / forgery prevention medium according to claims 1 to 6, and the information recording / forgery according to claims 1 to 6. In the prevention medium, an information recording forgery prevention foil is provided so that a support that can be separated by separation is in contact with a surface opposite to the first cholesteric layer.

  The invention according to claim 11 is one of the forms for utilizing the information recording / forgery prevention medium according to claims 1 to 6, and the information recording / forgery according to claims 1 to 6. In the prevention medium, a support that can be separated by separation is provided so as to be in contact with a surface opposite to the first cholesteric layer, and an information recording counterfeit is provided with an adhesive on the surface opposite to the support. Prevention transfer foil.

  The invention described in claim 12 shows a method for recording information on the information recording / counterfeit prevention medium, information recording / counterfeit prevention sticker, and anti-counterfeit article according to any one of the first to ninth aspects. The information recording / counterfeit prevention medium, the information recording / counterfeit prevention sticker, and the anti-counterfeit article according to claim 1 to claim 9 are irradiated with a laser to remove all or part of the color shift information recording layer. This is a recording method for recording information on a shift information recording layer.

  The invention described in claim 13 shows a method for recording information on the information recording anti-counterfeit foil described in claim 10, and is one of the forms for utilizing the method. The information recording forgery prevention foil is irradiated with a laser to remove the entire surface or a part of the color shift information recording layer to record information on the color shift information recording layer. This is an anti-counterfeit article containing information transferred to

  The invention according to claim 14 shows a method for recording information on the information recording forgery-preventing transfer foil according to claim 11, and is one of the forms for utilizing the method. Information formed by transferring information recorded on the color shift information recording layer to a sticker by irradiating the information recording forgery-preventing transfer foil with a laser to remove the entire surface or part of the color shift information recording layer. This is an anti-counterfeit article.

  As described above, according to one aspect of the present invention, two types of cholesteric color changes that are the same or different, a sumi absorption layer that does not transmit infrared wavelengths, a metal reflection layer, and a black absorption layer that transmits infrared wavelengths. , By irradiating a laser to the laminated medium laminated with the first cholesteric layer, the smear absorbing layer, the metal reflecting layer, the second cholesteric layer, and the black absorbing layer, the metal reflecting layer and the sumi absorbing layer are activated, The cholesteric layer, the smear absorbing layer, and the metal reflective layer can be removed and recorded as information. In other words, cholesteric sites where two or fewer types of color shift occur coexist in the same plane in a pattern, which has an appearance that conventional cholesteric media does not have, a color shift effect peculiar to cholesteric, and circular polarization reflection characteristics. A medium that can be individually formed at a low cost and an individual pattern forming method can be provided.

Sectional drawing explaining the layer structure of the color shift information recording layer which is the minimum structure of this invention. Sectional drawing explaining the layer structure of the information recording forgery prevention medium in which the variable color layer was provided in the color shift information recording layer. Sectional drawing explaining the layer structure of the information recording forgery prevention medium when a cholesteric is used for a variable color layer. The external view which shows a mode that the effect of the information recording forgery prevention medium after pattern removal is observed. Sectional drawing which shows an example of a layer structure of an information recording forgery prevention sticker. Sectional drawing which shows an example of a layer structure of information recording forgery prevention transfer foil. Sectional drawing which shows another information recording forgery prevention transfer foil structure. Sectional drawing which shows a mode that the color shift information recording layer was partially removed by infrared laser irradiation about the information recording forgery prevention sticker shown in FIG.

  As the information recording forgery prevention medium according to the present invention, a color shift information recording layer 10 composed of three types of layers, ie, a first cholesteric layer 101, a smear absorbing layer 102, and a metal reflective layer 103 as shown in FIG. Including a laminate as a constituent element.

  Here, the first cholesteric layer 101 has a feature that the color changes depending on the viewing angle and reflects right-handed or left-handed circularly polarized light. This is because a cholesteric liquid crystal having a helical molecular structure periodically reflects light having a wavelength corresponding to the pitch of the twisted structure because the refractive index of light periodically varies along the helical axis. by. Therefore, in the first cholesteric layer 101, it is possible to create a desired reflection color by controlling the pitch of the twisted structure. Then, by aligning these cholesteric liquid crystals, the respective molecules are uniformly arranged in layers, and the reflected lights are strengthened to reflect the color light as a whole. In addition, by arranging a black absorption layer having absorption in the visible light region on the back surface, the transmitted light is absorbed, and the reflected light is more emphasized, so that a so-called cholesteric color light can be confirmed. . Since the aligned cholesteric liquid crystal molecules have a helical structure, the reflected light is right-handed circularly polarized light or left-handed circularly polarized light. For this reason, the reflected light can be blocked by placing an appropriate circularly polarizing filter on the cholesteric liquid crystal layer. The cholesteric liquid crystal can be aligned by forming a layer on the alignment film. That is, it is possible to align by forming an alignment film on the substrate and forming a cholesteric liquid crystal layer on the alignment film. As the alignment film, a film obtained by rubbing a coating film of polyvinyl alcohol or polyimide can be used. Rubbing is possible using, for example, cotton or velvet. Moreover, it can also be made to orient in the direction of the shearing force by apply | coating, applying a shearing force. Or after forming a cholesteric liquid crystal layer, it can also align by applying a shearing force. In addition, the formed cholesteric liquid crystal layer can be oriented by irradiating polarized laser light, applying electrolysis or applying a magnetic field.

  In addition, this cholesteric liquid crystal layer is formed by applying a liquid crystal solution in which a liquid crystal substance having a nematic structure or a smectic structure, a chiral substance, a photopolymerizable polyfunctional compound and a polymerization initiator are mixed, and irradiating the coating film with ultraviolet rays. Can be formed. At this time, the chiral material bonds the liquid crystal materials to form the helical structure. Further, the photopolymerizable polyfunctional compounds are polymerized and cured to fix the cholesteric liquid crystal.

  In place of the liquid crystal material and the chiral material, an optical isomer liquid crystal material having an asymmetric carbon atom in the molecule is used, and the optical isomer liquid crystal material, the photopolymerizable polyfunctional compound, and the polymerization initiator are mixed. It is also possible to form a cholesteric liquid crystal layer by coating and irradiating with ultraviolet rays.

  In addition, the liquid crystal solution can be directly applied onto a substrate to form a cholesteric liquid crystal layer, or after forming a cholesteric liquid crystal layer on another support, an adhesive is used to form the substrate. The cholesteric liquid crystal layer may be formed on the substrate by bonding or transferring using a method such as lamination.

  Next, as the photopolymerizable polyfunctional compound, a polymerizable functional group, a polycondensable functional group, or a monomer or oligomer having two or more functional groups effective for polyaddition in the molecule can be used. In addition to this photopolymerizable polyfunctional compound, a monofunctional monomer or oligomer can be used in combination.

  Examples of the radical photopolymerizable polyfunctional monomer include trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, and the like. Examples of the radical photopolymerizable polyfunctional oligomer include polyurethane polyacrylate, epoxy resin polyacrylate, acrylic polyol polyacrylate, and the like. Examples of the radical photopolymerizable monofunctional monomer include alkyl (C1 to C18) (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, alkylene (C2 to C4) glycol (meth) acrylate, In alkoxy (C1-C10) alkyl (C2-C4) (meth) acrylate, polyalkylene (C2-C4) glycol (meth) acrylate, alkoxy (C2-C10) polyalkylene (C2-C4) glycol (meth) acrylate, etc. Can be mentioned. Moreover, an aromatic epoxy compound, an alicyclic epoxy compound, and a glycidyl ester compound can be used. A three-dimensional cross-linkable liquid crystal polyorganosiloxane can also be used.

  Subsequently, as the polymerization initiator, a radical photopolymerization initiator or a cationic photopolymerization initiator can be used. In addition to these photopolymerization initiators, a sensitizer and a peroxide can be used in combination.

  As the radical photopolymerization initiator, known ones such as acetophenone series such as α-hydroxyacetophenone series and α-aminoacetophenone series, benzoin ether series, benzyl ketal series, α-dicarbonyl series, α-acyl oxime ester series, etc. Specifically, α-aminoacetophenone, acetophenone diethyl ketal, benzyldimethyl ketal, α-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methylphenylpropanone, benzophenone, Michler's ketone, isopropylthioxanthone, benzophenone and N-methyl The combined use with diethanolamine etc. are mentioned. Conventionally known cationic photopolymerization initiators can be used without particular limitation, and more preferably, known cationic sensitizers and peroxides can be used in combination as appropriate. For example, allyl iodonium salt-α-hydroxyacetophenone, triallylsulfonium salt, metallocene compound-peroxide combined system, metallocene compound-thioxanthone combined system, metallocene compound-anthracene combined system, and the like.

  And as a coating apparatus utilized when apply | coating the liquid crystal solution which mixed these liquid crystal substance, a chiral substance, a photopolymerizable polyfunctional compound, and a polymerization initiator, a comma coater, a micro gravure coater offset, etc. can be used. The thickness may be 0.5 to 20 μm. The thickness is preferably 2 to 10 μm, and as the thickness increases, the reflectance on the cholesteric surface increases and the color is vividly developed. On the other hand, when removing the color shift information recording layer 10 with an infrared laser, a large amount of energy is required.

Further, when the coating film is irradiated with ultraviolet rays for polymerization, in order to prevent polymerization inhibition by oxygen, the oxygen gas concentration can be lowered and irradiated with ultraviolet rays in the presence of an inert gas such as nitrogen. Alternatively, it is possible to irradiate with ultraviolet rays after coating with an oxygen barrier coating. An example of the oxygen barrier film is polyvinyl alcohol.
Here, the smear absorbing layer 102 is a black layer that absorbs at least the visible light region. Cholesteric is necessary to develop a cholesteric color by having an absorption layer that absorbs visible light wavelengths on the back surface. There are two forms of the sumi absorption layer 102. The first form is a relatively thick form with a film thickness typically exceeding 1 μm, and the second form is a film thickness. Is a relatively thin film form. The first form needs not to transmit infrared wavelengths including the laser wavelength to be irradiated to remove the color shift information recording layer 10, while the second form absorbs the visible light region as described above. Any black layer may be used and may or may not transmit infrared wavelengths. These forms will be described in detail later.

  The metal reflection layer 103 is a metal reflection layer 103 that does not transmit at least the infrared wavelength region. Examples of the metal include aluminum, copper, iron, nickel, and cobalt. For example, the metal foil may be formed as a thin film by a vacuum deposition method, a sputtering method, wet plating, or a metal foil obtained by stretching the metal. May be formed by pasting with a known adhesive or pressure-sensitive adhesive, and the thickness is preferably about 10 nm to 20 μm. The metal reflective layer 103 is a layer that plays a main role when the color shift information recording layer 10 is removed by infrared laser irradiation.

  The color shift information recording layer 10 composed of these three kinds of minimum constituent elements activates the sumi absorption layer 102 and the metal reflection layer 103 by irradiating with an infrared laser, and the surface of each material and the atoms or molecules inside. The bond is broken and a phase change such as rapid melting, evaporation, or vaporization is generated, so that the first cholesteric layer 101 is blown away, and at the same time, the smear absorbing layer 102 and the metal reflective layer 103 are also removed. For this reason, since the color shift information recording layer 10 is removed when irradiated with an infrared laser, the color shift information recording layer 10 is actually used in a state of being supported by a base material or a patch.

  The condition under which the color shift information recording layer 10 is removed by the infrared laser depends on the film thickness of each layer, the form and state of the sumi absorption layer 102, and the total amount of energy given by the irradiated infrared laser. The energy for removing these layers is mainly generated by the sudden phase change of the metal reflection layer 103 by the infrared laser. However, the thickness of the Sumi absorption layer 102 or the first cholesteric layer 101 is thick or the layer is strong. If there is, the color shift information recording layer 10 cannot be removed.

  In addition, since the power of the infrared laser affects the speed at which the metallic reflective layer 103 undergoes a phase change, the stronger one can obtain more energy for removing the other layers. This may affect parts other than the recording layer 10. For this reason, the thinner the thickness of the smear absorbing layer 102 is, the less energy is required to remove the color shift information recording layer 10.

  Here, two forms of the sumi absorption layer 102 will be described. The first form is typically a thick form having a film thickness exceeding 1 μm, and it is necessary not to transmit infrared wavelengths including the laser wavelength to be irradiated in order to remove the color shift information recording layer 10. . As this, for example, there is a method of forming a film by printing a printing ink, in which a carbon black pigment is dispersed in a binder such as a polymer resin, by a gravure printing method, a screen printing method, an offset printing method, or the like. Instead of the carbon black pigment, an organic black pigment represented by aniline black, perylene black, or the like, or inorganic black containing chromium, manganese, iron, cobalt, copper, etc., titanium black, or the like may be used. Further, when the first cholesteric layer 101 is formed by transfer by lamination or the like, the smear absorbing layer 102 may be obtained by using a laminate adhesive material as a binder and previously dispersing the black pigment as mentioned above. . Alternatively, a layer that is black and does not transmit infrared wavelengths may be used as a result of providing a reflection layer on the structure forming layer that forms a fine structure and performing structure absorption.

  In such a form, the infrared wavelength is absorbed or reflected by the infrared laser, and the phase change is caused only by a black pigment or a small part where structure absorption is performed. Most of them are transparent and do not change with infrared wavelengths. Therefore, it is necessary to melt and vaporize the binder and the structure-forming layer that are in contact with the heat energy generated by the phase change of the black pigment or the like. This is a thin film, and it is good if the color shift information recording layer 10 can be removed only by the energy generated by the phase change of the metal reflective layer 103. However, for example, when using printing ink as described above, the smear absorbing layer 102 is sufficient In order to remove the color shift information recording layer 10, a thickness of the metal reflection layer 103 and a large irradiation laser power are required. Therefore, it is preferable that the black pigment content is as large as possible.

  Subsequently, in the case where the film thickness which is the second form of the sumi absorption layer 102 is 1 μm or less, even if the infrared wavelength including the laser wavelength irradiated for removing the color shift information recording layer 10 is transmitted, You don't have to. If the infrared wavelength is not transmitted, the phase change occurs due to absorption or reflection, similar to the first form of the smear absorbing layer 102, and the infrared laser reaches the metal reflecting layer 103 after the smear absorbing layer 102 is removed. . Even if the infrared wavelength is transmitted, if the film is sufficiently thin, it is possible to remove the smear reflection layer only with the energy generated by the phase change when only the metal reflection layer 103 is activated by the infrared laser. For this reason, infrared wavelengths may be transmitted.

  For example, after forming copper as the metal reflecting layer 103 by a vacuum deposition method or a sputtering method, the surface of the surface is made black by oxidizing with sodium chlorite or the like. By forming a copper oxide thin film, this thin film can be used as the Sumi absorption layer 102. Alternatively, after forming aluminum as the metal reflective layer 103 by a vacuum deposition method, a sputtering method, or the like, the surface is anodized using an anodic oxidation method, and then black coloring is performed. Alternatively, for example, black chrome plating, black nickel plating, black stainless coating, or the like by blackening treatment with other metals may be used.

  Up to now, the first and second forms of the sumi absorption layer 102 have been described with a typical value separated by a film thickness of 1 μm. However, when the metal reflection layer 103 is activated by an infrared laser, The color shift information recording layer 10 including the first cholesteric layer 101 can be classified only by the energy generated in the above. Therefore, strictly speaking, when the metal reflection layer 103 alone cannot be removed by activation with an infrared laser, the first form of the Sumi absorption layer 102 can be removed, and when it can be removed, the second form of the Sumi absorption layer 102 can be removed. is there.

  Here, a new form is demonstrated. FIG. 2 shows the color shift information recording layer 10 described so far in which the variable color layer 201 is provided so as to be in contact with the metal reflection layer 103. This variable color layer is a layer that has the function of changing the color depending on the viewing angle. By providing a black absorption layer on the back surface like a cholesteric or multilayer film, a color change like a cholesteric color occurs. By printing various color shift inks represented by pearl pigments dispersed in a binder by various printing methods such as gravure printing method, screen printing method, offset printing method, etc. It may be obtained, or it may be a color change due to multilayer thin film interference effect by multilayer deposition, or a diffractive structure is formed in the structure forming layer by hot-pressure embossing, and is representative of ZnS, TiO, etc. A high refractive index material that transmits the infrared wavelength is formed into a thin film by vacuum deposition or sputtering. Therefore, it may be obtained by creating a so-called transparent hologram, or excited by irradiating illumination represented by an ultraviolet lamp, emitting visible light or infrared wavelength, and transmitting infrared wavelength. By printing fluorescent inks obtained by dispersing fluorescent pigments in binders or dissolving fluorescent dyes with the same fluorescent properties by various printing methods such as gravure printing, screen printing, and offset printing The color change may be generated by irradiating excitation illumination.

Subsequently, a case where cholesteric is used for the above-described variable color layer 201 to form a second cholesteric layer will be described in detail.
A cholesteric color appears when a black absorption layer is provided on the back surface of the cholesteric, but the absorption layer at this time transmits infrared wavelengths including a laser wavelength to be irradiated to remove the color shift information recording layer 10. For example, as shown in FIG. 3, the second cholesteric layer 301 and the black absorbing layer 302 are made to be the variable color layer 201 so as to be in contact with the metal reflective layer 103 of the color shift information recording layer 10 as shown in FIG. 3. Is formed.

  For the black absorbing layer 302 that transmits infrared wavelengths including the laser wavelength irradiated to remove the color shift information recording layer 10, for example, black ink known as a color mixing smear can be used. This is obtained by printing printing ink in which a mixture of three types of pigments of cyan, magenta, and yellow is dispersed in a binder by various printing methods such as gravure printing, screen printing, and offset printing. IR black material used for the cover of the tip of a remote control, etc., which absorbs visible light wavelength and transmits black infrared light but is IR black pigment. Similar to the above-mentioned mixed color sumi, it may be obtained by dispersing in a binder and printing, or a printing ink obtained by dissolving an IR black dye may be obtained by printing in the same manner. By not forming this layer with a material that does not transmit infrared wavelengths, such as the Sumi absorption layer 102, it is possible to prevent the layer from being activated and removed when irradiated with an infrared laser.

  Although the second cholesteric layer 301 has the same color shift as that of the first cholesteric layer 101, the rotation direction of the circularly polarized light may be reversed, and the first cholesteric layer 101 Although the color shift is different, the rotation direction of the circularly polarized light may be the same, and the color shift is different from that of the first cholesteric layer 101, and the rotation direction of the circularly polarized light is also reversed. It may be configured.

The effects obtained by these configurations will be described in order.
First, a case will be described in which the second cholesteric layer 301 has the same color shift as that of the first cholesteric layer 101 but has a configuration in which the rotation direction of circularly polarized light is reversed.

  In such a configuration, it is difficult to visually distinguish the difference between the first cholesteric layer 101 and the second cholesteric layer 301 after partially removing the first cholesteric layer 101 with an infrared laser. However, since the rotation direction of the circularly polarized light is reversed, when the first and second cholesteric layers are observed with a circularly polarized filter that shields right-handed circularly polarized light and a circularly polarized light filter that shields left-handed circularly polarized light, One can observe the normal cholesteric color and the other can observe the appearance of black, so the pattern can be recognized from the contrast difference between the two. It is possible to provide a function like a so-called latent image. The same effect can be confirmed whether the filter is observed while being superimposed on the medium, or when the filter is viewed remotely with the filter close to the eyes.

  The second cholesteric layer 301 is formed by the same method as the first cholesteric layer 101 and the retardation layer having a retardation value of λ / 2 that rotates the phase difference by 180 degrees at the visible light wavelength. A layer in which a cholesteric layer formed using a material is in contact with each other to form a second cholesteric layer 301 can be considered. In this case, the retardation layer needs to be provided in contact with the metal reflective layer 103 side.

  As another method for forming the second cholesteric layer 301, a cholesteric material having a rotation direction of circularly polarized light opposite to that of the cholesteric material constituting the first cholesteric layer 101 is used, and a chiral is added. It is also conceivable to use an agent whose amount is adjusted so as to have a helical periodic pitch that has the same color shift as the first cholesteric layer 101.

  Next, a case will be described in which the second cholesteric layer 301 is configured to have the same rotational direction of circularly polarized light, although the color shift is different from that of the first cholesteric layer 101.

  In such a configuration, after the first cholesteric layer 101 is partially removed by an infrared laser, the appearance is very unique in that two different color shift regions are present in the same plane. Can be realized.

  In addition, when observed with a circularly polarizing filter, there are two choices of whether the entire surface is black or the same cholesteric color can be observed. Such two types of cholesteric layers have a feature that can be easily realized only by changing the amount of the chiral agent added to the cholesteric.

  Next, the case where the second cholesteric layer 301 is configured to have a color shift different from that of the first cholesteric layer 101 and the rotation direction of circularly polarized light is reversed will be described.

  In the case of such a configuration, after the first cholesteric layer 101 is partially removed by an infrared laser, two different types of color shift regions are present in the same plane as before. In addition to being able to realize a unique appearance, when the first and second cholesteric layers are observed with a circularly polarizing filter, one can observe the normal cholesteric color and the other is black. You can also In order to form such a second cholesteric layer 301, a cholesteric material adjusted to have different helical periodic pitches by changing the amount of chiral agent added while the rotational direction of circularly polarized light is the same, as described above. A method may be considered in which a second cholesteric layer 301 is formed by laminating and laminating a retardation layer having a retardation value of λ / 2 that shifts the phase of polarized light by 180 degrees at a visible light wavelength.

  As another method, the first cholesteric layer 101 is a cholesteric material in which the rotation direction of circularly polarized light is reversed, and different spiral periods are obtained by changing the amount of the chiral agent added to each cholesteric material. A cholesteric material adjusted to a pitch may be the second cholesteric layer 301.

  FIG. 4 exemplifying specific effects for such a configuration is shown in FIG. 4 where the second cholesteric layer 301 is reflected by the information recording forgery prevention medium 40 from which the color shift information recording layer 10 has already been partially removed by an infrared laser. The state where the circularly polarizing filter 41 which shields the circularly polarized light to be overlapped is shown.

  The first cholesteric layer 101 where the circularly polarizing filter 41 is not overlaid and the second cholesteric layer 301 where the color shift information recording layer 10 has been partially removed by an infrared laser and exposed are different color shifts. It can be visually recognized as a character pattern of “TP”.

  Further, since the circularly polarized light reflected by the first cholesteric layer 401 on which the circularly polarizing filter is superimposed is not shielded by the circularly polarizing filter, a color shift having an appearance similar to that of the first cholesteric layer 101 can be observed.

  On the other hand, the circularly polarized light reflected by the second cholesteric layer 402 on which the circularly polarizing filter is superimposed appears black because it is shielded by the circularly polarizing filter.

  A method of actually using the information recording / forgery prevention medium as described above will be described.

  By providing an adhesive layer on the opposite side of the first cholesteric layer 101 of the information recording / forgery prevention medium, it can be used as an information recording / forgery prevention sticker. In this case, the color shift information recording layer 10 can be partially removed by infrared laser irradiation before or after being attached to an article.

  FIG. 5 shows an example of the specific layer structure. Reference numeral 501 denotes a transparent substrate, which includes various materials such as a polyethylene terephthalate film, a polyethylene naphthalate film, a polypropylene film, a polyethylene film, a polymethyl methacrylate film, a polystyrene film, a nylon film, a polycarbonate film, an acrylic film, and a triacetyl cellulose film. A film can be used.

  Although the thickness can be used without limitation depending on various applications, it is preferably about 10 μm to 100 μm because it is a sticker application.

  A metal reflective layer 103 is formed on one surface of the transparent substrate 501, a laminate adhesive material in which a carbon black pigment is dispersed is formed as a sumi absorption layer 102, and the first cholesteric formed on the substrate in advance. After laminating and transferring the layer 101, the first cholesteric layer 101 is formed by peeling the substrate.

  In this way, the transparent laminate adhesive material 502 is formed on the surface of the transparent base material 501 on which the color shift information recording layer 10 is formed, on the opposite side of the color shift information recording layer 10, and the base material is preliminarily formed. After the second cholesteric layer 301 formed on the substrate is laminated and transferred, the black absorbent layer 302 is formed so as to be in contact with the second cholesteric layer 301 formed by peeling the base material, and then the adhesive layer By laminating 503, an information recording forgery prevention sticker can be created. Further, a separator may be attached to the adhesive layer 503 as necessary.

  The adhesive layer 503 is, for example, a single adhesive such as vinyl chloride-vinyl acetate copolymer, polyester polyamide, acrylic, butyl rubber, natural rubber, silicon, polyisobutyl, or alkyl methacrylate, vinyl ester, Aggregating components such as acrylonitrile, styrene, vinyl monomers, unsaturated carboxylic acids, hydroxy group-containing monomers, modifying components such as acrylonitrile, polymerization initiators, plasticizers, curing agents, curing accelerators, antioxidants What added the additive of these etc. as needed can be used. For the formation, a gravure printing method, an offset printing method, a screen printing method, or the like can be used.

Moreover, you may provide so that it may stick together by roll lamination using the adhesive member in which both surfaces were comprised with the film separator.

  For the transparent substrate 501, for example, when a film produced by stretching and having optical anisotropy, such as a polyethylene terephthalate film or a nylon film, is used, for example, the first cholesteric layer 101 and the second cholesteric layer 301. Are circularly polarized light in the same direction, the circularly polarized light reflected from the second cholesteric layer 301 has its polarization component changed by the transparent substrate 501, so when observed through a circularly polarizing filter, the first cholesteric layer 101 Is observed differently. For this reason, even if the color shifts of the first cholesteric layer 101 and the second cholesteric layer 301 are exactly the same, the difference can be confirmed by the circularly polarizing filter.

  On the other hand, when the transparent substrate 501 is an optically isotropic film such as an acrylic film or a triacetyl cellulose film, the polarization component of the circularly polarized light reflected from the second cholesteric layer 301 changes. Can be observed without any problem.

  Next, as a method of actually utilizing the information recording / counterfeit prevention medium, a description will be given of a foil configuration that has a support and is finally transferred to an article and peeled off.

  FIG. 6 shows a layer structure of an information recording forgery-preventing transfer foil in which the color shift information recording layer 10 is removed by an infrared laser after transferring and peeling the support.

  Reference numeral 601 in FIG. 6 denotes a support base material that serves as a support for the transfer foil that is peeled off after transfer. The material is a base material that can be peeled off from the first cholesteric layer 101, such as polyethylene terephthalate and polyethylene naphthalate, and is also oriented itself. Since this base material is peeled off after being transferred, it is not necessary to be transparent and the thickness can be freely used. The first cholesteric 101 is formed on the support base 601 and the sumi absorption layer 102 is laminated.

  Subsequently, after the metal reflective layer 103 is formed using a vacuum deposition method or the like, the alignment layer 602 is provided. The alignment layer 602 is for orienting the second cholesteric layer 301 to be provided later. Since the alignment layer 602 itself needs to be aligned, after the metal reflective layer 103 in contact with it is rubbed, for example, a nematic structure or smectic You may obtain by apply | coating the liquid crystal solution which mixed the photopolymerizable polyfunctional compound and the polymerization initiator to the liquid crystal substance which has a structure, and irradiating with an ultraviolet-ray and making it harden | cure. The film thickness at this time may be about 10 nm to 20 μm, and may be very thin if it is used only as an alignment film.

  In addition, when it is very thin, a chiral substance or the like may be mixed with the liquid crystal substance. Particularly, when the alignment layer 602 has a phase difference value of λ / 2 that shifts the phase of polarized light by 180 degrees at the visible light wavelength, it also has an effect of reversing the rotation direction of the circularly polarized light of the second cholesteric layer 301.

  Further, in order to obtain a more aligning force, a polyvinyl alcohol resin or a polyimide resin is applied as an alignment film so as to be in contact with the metal reflective layer 103, and after the rubbing treatment, the liquid crystal material is applied and cured. The alignment layer 602 may be used. On the orientation layer 602 thus obtained, the second cholesteric layer 301 can be oriented.

  Subsequently, an information recording forgery-preventing transfer foil made by laminating the black absorbing layer 302 and the adhesive layer 603 is affixed to the corresponding article, and the supporting base material 601 is peeled off. The recording layer 10 can be removed.

  The adhesive layer 603 varies depending on the object to be applied, but when transferred to paper, for example, an aliphatic hydrocarbon resin, an alicyclic hydrocarbon resin, an aromatic hydrocarbon resin, α-pinene and / or β -Hot melt adhesives such as terpene resin, rosin resin, hydrogenated rosin resin, styrene resin, coumarone / indene resin, etc., containing pinene as a component, with addition of carnauba wax as required Use. When affixing, for example, heat and pressure of about 120 to 180 degrees are applied.

  Another transfer foil configuration is shown in FIG. This configuration is a type in which the color shift information recording layer 10 is removed with an infrared laser before pasting and then transferred to the subject of pasting.

  This is because, in the order of the black base layer 302, the alignment layer 602, the second cholesteric layer 301, the metal reflection layer 103, the smear absorption layer 102, the alignment layer 602, the first cholesteric layer 101, and the adhesive layer 603. It is necessary to select a combination in which the black absorbent layer 302 and the supporting base material 601 are peelable. Since there is no need to orient the cholesteric as in the configuration shown in FIG. 6, a substrate that is not molecularly oriented may be used.

  Further, a peeling layer may be provided between the support base 601 and the black absorption layer 302. In the case of this configuration, the color shift information recording layer 10 corresponds to the metal reflective layer 103, the smear absorbing layer 102, the alignment layer 602, and the first cholesteric layer 101.

  In the case of this configuration, since the color shift information recording layer 10 can be patterned before sticking, since it can be patterned in advance at the stage of manufacturing the transfer foil, various patterns patterned into specific patterns can be used. This is an effective method when you want to affix it to various articles. In addition, since the confirmation of the phenomenon is performed from the attached article side, the article needs to be transparent. Moreover, in order to confirm circularly polarized light, it is necessary to pay attention to whether the article has optical anisotropy.

  Further, the adhesive layer 603 may be removed from the configuration illustrated in FIG. In that case, the adhesive layer 603 needs to be pasted on the article to be pasted in advance, but in the case of the configuration illustrated in FIG. 7, when the color shift information recording layer 10 is removed by an infrared laser, the adhesive layer 603 is removed. However, when the adhesive layer 603 is provided on the object to be pasted, this problem does not occur and the color shift information recording layer is formed by an infrared laser. The energy for removing 10 is also smaller.

  Finally, a method for removing the color shift information recording layer 10 with an infrared laser will be described.

  The laser to be irradiated is a near-infrared wavelength laser such as a CO2 laser or various solid-state lasers such as an Nd: YAG laser. An Nd; YAG laser having a wavelength of 1064 nm is preferable. As a pattern, a unique logo mark, a manufacturer name, a serial number, or a barcode corresponding to an object to which the medium is applied is used. Alternatively, a digital watermark obtained by encoding a specific code may be added to these images.

  When the color shift information recording layer 10 is removed, the removed matter is generated as debris. Therefore, the color shift information recording layer 10 is preferably directed downward as much as possible. In some cases, when infrared laser irradiation is performed with the color shift information recording layer 10 facing upward, a mechanism that collects debris soared by simultaneously introducing strong intake air and exhaust gas before it falls on the medium is collected. It is good to introduce.

  FIG. 8 is a cross-sectional view of the information recording counterfeit prevention sticker shown in FIG. 5 in which the color shift information recording layer 10 is partially removed by infrared laser irradiation.

  Although the present invention has been described assuming that the color shift information recording layer 10 is removed by irradiation with an infrared laser, the wavelength of the laser for removing the color shift information recording layer 10 is in the infrared region. It is not necessary to limit to this, and other wavelengths can be used. Since it is preferably outside the visible light region, an ultraviolet laser can be used. For example, an excimer laser, various solid-state lasers, mode-locked lasers, or the like may be used.

  In that case, the Sumi absorption layer 102 needs to absorb the visible light wavelength uniformly, and further absorb or reflect the wavelength in the ultraviolet region including the laser wavelength to be utilized, and the black absorption layer 302 absorbs the visible light wavelength uniformly. However, it is necessary to transmit the ultraviolet region. The other layers also need to transmit wavelengths in the ultraviolet region including the laser wavelength to be utilized, but the basic design purpose has been described above.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the spirit of the present invention.

Examples of the present invention will be described below.
A first cholesteric ink having the following composition was applied to a 16 μm thick polyethylene terephthalate film using a wire bar, and adjusted to a thickness of 3 μm after drying and curing, and dried at 80 ° C. for 1 minute. After that, the first cholesteric layer was obtained by curing by irradiation with 500 mJ with a high-pressure mercury lamp.

<First cholesteric ink composition>
Nematic liquid crystal (Paliocolor LC242) [manufactured by BASF] 30 parts by weight Chiral agent (Paliocolor LC756) [manufactured by BASF] 1.5 parts by weight Polymerization initiator (Irgacure 184) [manufactured by BASF] 1.5 parts by weight Solvent (Methyl ethyl ketone) 67 parts by weight Subsequently, with respect to the black ink having the following composition, the ink adjusted so that the film thickness after drying becomes 3 μm is applied using a wire bar and dried at 100 ° C. for 1 minute. The Sumi absorption layer was obtained. Further, after aging for 12 hours in an 80 ° C. environment, an aluminum film having a thickness of 50 nm was formed on the surface of the Sumi absorption layer by a resistance heating vacuum deposition method.

<Black ink composition>
90 parts by weight of black ink (NEWLP super black) [manufactured by Toyo Ink Manufacturing Co., Ltd.] 10 parts by weight of curing agent (LP super hardener) [manufactured by Toyo Ink Manufacturing Co., Ltd.] After adjusting the film thickness to 3 μm using a wire bar and drying at 100 ° C. for 2 minutes, rubbing cloth FINE PUFF YA-20-R (manufactured by Yoshikawa Chemical Co., Ltd.) The entire surface was rubbed in a uniaxial direction.

On this surface, the liquid crystal ink shown below was applied using a wire bar so that the film thickness after drying and curing was 1.5 μm, dried at 30 ° C. for 5 minutes, and then applied to a high-pressure mercury lamp. Then, an alignment layer was obtained by curing with irradiation of 1000 mJ.

<Alignment film ink>
Polyvinyl alcohol resin (Povar 117) [manufactured by Kuraray Co., Ltd.] 10 parts by weight Solvent (isopropyl alcohol) 4.5 parts by weight Solvent (water) 85.5 parts by weight <Liquid crystal ink>
Liquid crystal (UCL-008) [manufactured by Dainippon Ink & Chemicals, Inc.] 30 parts by weight Polymerization initiator (Irgacure 184) [manufactured by BASF] 1.5 parts by weight Solvent (methyl ethyl ketone) 34.25 parts by weight Solvent (toluene) 34. 25 parts by weight Furthermore, the second cholesteric ink shown below was applied, dried and cured under the same procedure and conditions as when the first cholesteric ink layer was obtained to obtain a second cholesteric layer having a thickness of 3 μm.

<Second cholesteric ink composition>
Nematic liquid crystal (Paliocolor LC242) [manufactured by BASF] 30 parts by weight Chiral agent (Paliocolor LC756) [manufactured by BASF] 2.0 parts by weight Polymerization initiator (Irgacure 184) [manufactured by BASF] 1.5 parts by weight Solvent (Methyl ethyl ketone) 66.5 parts by weight Subsequently, the mixed color Sumi ink shown below was applied using a wire bar so that the film thickness after drying was 3 μm, and dried at 100 ° C. for 1 minute to obtain black. An absorbent layer was obtained.

<Color mixing sumi ink>
90 parts by weight of mixed color ink (FL KONSUMI) [manufactured by Toyo Ink Manufacturing Co., Ltd.] Curing agent (LP super curing agent) [manufactured by Toyo Ink Manufacturing Co., Ltd.] 10 parts by weight Further, for the adhesive shown below, the film thickness after drying is 5 μm. What was adjusted so that it may become was apply | coated using the wire bar, and it dried at 80 degreeC for 2 minute (s), and obtained the contact bonding layer.

<Adhesive composition>
Polyolefin resin (Aurolen 100) [Nippon Paper Chemical Co., Ltd.] 20 parts by weight Silica particles (Silo Hovic 505) [Fuji Silysia Co., Ltd.] 5 parts by weight Solvent (toluene) 75 parts by weight After the foil is cut into stripes with a width of 10 mm, it is laminated on a coated paper with a basis weight of 90 kilograms while applying a temperature of 160 degrees and appropriate pressure, and then transferred by peeling the polyethylene terephthalate film that is the support substrate. Went.

  After printing the pattern of the gift certificate on such coated paper by offset printing on the part other than the transfer foil, it is cut to the size of the gift certificate and fixed on the fixing base, and the transfer foil portion is compressed with compressed air in the horizontal direction. Using YVO4 laser marker MD-V9610A (manufactured by Keyence Corporation) while jetting, under conditions of output 60%, scan speed 2000 mm / s, switch frequency 100 Hz, logo mark, OCR font serial number and GS1 standard data bar pattern The transfer foil color shift information recording layer was removed.

  The information record forgery-preventing transfer foil part of the gift certificate obtained in this way looks green from the front when irradiated with the laser, and red when not irradiated with the logo mark, serial number, and bar. The code etc. could be confirmed visually. When viewed from an angle, the laser-irradiated part appeared blue and the non-irradiated part appeared green. In addition, when the circularly polarized filter is overlapped, the laser irradiated part looks black, and by photographing with the CCD camera installed at the tip of the camera, the OCR font serial number obtained as a high contrast image, The barcode data could be read.

  The present invention is affixed and transferred to various certificates such as banknotes, bonds, gift certificates, checks and other securities, securities, credit cards, ID cards, official documents, important documents, and various products and their packaging materials. As a result, it is possible to provide information on the safety of the affixed product and information on counterfeit products by guaranteeing that the product is authentic and collating the information given individually with the database via the Internet. Or can be used for various services.

10 ... Color shift information recording layer 40 ... Information recording anti-counterfeit medium already partially removed by laser,
41... Circularly polarizing filter 101... First cholesteric layer 102... Sumi absorption layer 103.. Metal reflection layer 201.. Variable color layer 301.. Second cholesteric layer 302. First cholesteric layer 402 overlaid with filter, second cholesteric layer 501 overlaid with circular polarizing filter, transparent substrate 502, laminated adhesive material 503, adhesive layer 601, support substrate 602・ Orientation layer 603 ・ ・ Adhesive layer

Claims (14)

Including at least a first cholesteric layer, a smear absorbing layer, and a metal reflective layer,
An information recording forgery prevention medium, characterized in that a color shift information recording layer is provided. In the information recording forgery prevention medium according to claim 1,
An information recording forgery prevention medium, characterized in that a variable color layer is provided so as to be in contact with a surface of the color shift information recording layer in contact with the metal reflective layer. In the information recording forgery prevention medium according to claim 2,
An information recording counterfeit prevention medium, wherein the variable color layer is composed of at least a second cholesteric layer and a black absorbing layer, and is provided so that the metal reflective layer and the second cholesteric layer are in contact with each other. In the information recording forgery prevention medium according to claim 3,
Circularly polarized light reflected from the first cholesteric layer and the second cholesteric layer, wherein the first cholesteric layer is left-handed polarized light or right-handed polarized light, and the second cholesteric layer is circularly polarized light opposite to the first cholesteric layer. Information recording counterfeit prevention medium. In the information recording forgery prevention medium according to claim 3 or 4,
An information recording forgery preventing medium characterized in that the first cholesteric layer and the second cholesteric layer have the same color change. In the information recording forgery prevention medium according to claim 3 or 4,
A medium for preventing forgery of information recording, characterized in that the color change between the first cholesteric layer and the second cholesteric layer is different. In the information recording forgery prevention medium according to any one of claims 1 to 6,
An information recording counterfeit prevention sticker characterized in that an adhesive layer is provided on the opposite side of the first cholesteric layer.   An anti-counterfeit article obtained by sticking the information recording anti-counterfeit sticker according to claim 7 to an article. In the information recording forgery prevention medium according to any one of claims 1 to 6,
A peelable and separable support is provided so as to be in contact with the first cholesteric layer, and an information recording forgery prevention transfer foil provided with an adhesive layer on the surface opposite to the support is attached to the article, An anti-counterfeit article characterized by peeling a support. In the information recording forgery prevention medium according to any one of claims 1 to 6,
An information recording forgery-preventing foil, wherein a peelable and separable support is provided so as to be in contact with a surface opposite to the first cholesteric layer. In the information recording forgery prevention medium according to any one of claims 1 to 6,
An information recording characterized in that a peelable and separable support is provided in contact with the surface opposite to the first cholesteric layer, and an adhesive layer is provided on the surface opposite to the support. Anti-counterfeit transfer foil.   By irradiating a laser on the information recording / counterfeit prevention medium, the information recording / counterfeit prevention sticker, and the anti-counterfeit article according to any one of claims 1 to 9, the whole or a part of the color shift information recording layer is removed, A recording method comprising recording information on a color shift information recording layer.   The information recording forgery prevention foil according to claim 10 is irradiated with a laser to remove the entire surface or a part of the color shift information recording layer, whereby information is recorded on the color shift information recording layer. An anti-counterfeit article containing information, wherein the article is transferred to an applied patch.   The information recording forgery-preventing transfer foil according to claim 11 is irradiated with a laser to remove all or part of the color shift information recording layer, thereby recording information on the color shift information recording layer into a patch An anti-counterfeit article containing information characterized by being transferred.

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