JP4743448B2 - Authenticity discriminator and authenticity discriminating structure transfer sheet - Google Patents

Description

  The present invention provides an authentic identification structure in which a cholesteric liquid crystal layer having fine irregularities of a light diffraction structure such as a hologram is accompanied by a heat resistance improving layer on the fine irregularities side, and an information recording medium such as cards and securities. The present invention relates to an authenticity identifier applied to a representative authenticity identification object, and a transfer sheet for producing such an authenticity identifier.

  Credit cards and savings cards, if forged and used, can damage the cardholder, card company or financial institution. Similarly, forgery is a problem, such as 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 medium holding information having economic or social value, and it is desired to have a function of identifying its authenticity 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 medium on 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 order to prevent damage caused by forgery, it is desirable that these have a function of identifying their authenticity.

  Conventionally, for the purpose of preventing counterfeiting of information recording media 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. In many cases, a hologram is applied as an authentic discriminating element (referred to as an authentic discriminating structure). However, the manufacturing method of the hologram itself is known, and when the hologram is merely a visual hologram, it is difficult to distinguish between a genuine hologram and a counterfeited hologram because it is originally precise. .

  A general hologram is formed using a synthetic resin, particularly an ultraviolet curable resin, and hologram interference fringes are formed as fine irregularities on the surface of the cured resin layer. Thus, the layer containing the light has a property of reflecting either the left circularly polarized light or the right circularly polarized light.Therefore, only when either the left circularly polarizing plate or the right circularly polarizing plate is used, the color can be seen. In addition, since the fine irregularities such as holograms can be formed on the surface of the layer, the authentic identification structure using the cholesteric liquid crystal layer as a layer for forming a light diffraction structure such as a hologram is made of synthetic resin or ultraviolet rays. Compared to the case where a curable resin is used, resistance to forgery prevention is increased, which is preferable. (See Patent Document 1)

However, the authentic identification structure comprising the above cholesteric liquid crystal layer has insufficient heat resistance compared to the authentic identification structure obtained by using a general hologram forming material. When applying the structure to the information recording medium while applying heat and pressure, the fine irregularities of the light diffractive structure such as holograms are easily lost by heating and pressurizing, and the authentic cholesteric liquid crystal layer is used. The authenticity identification object to which the sex identification structure is applied is also likely to have insufficient heat resistance of the authenticity identification structure.
JP 2000-25373 A

  In the present invention, an authenticity identification structure in which an optical diffraction structure such as a hologram made of a cholesteric liquid crystal layer is conventionally applied to heat resistance when applied to an authenticity identification object and to an authenticity identification object. It is an object to solve the problem of insufficient heat resistance later.

  In the present invention, a heat resistance improving layer made of an ionizing radiation curable resin or a low-temperature-treated thermosetting resin is provided on the fine concavo-convex side of the authentic identification structure formed of a cholesteric liquid crystal layer in which a light diffraction structure such as a hologram is formed as fine concavo-convex. By laminating and forming a concavo-convex structure having the same shape as the fine concavo-convex structure on the surface of the heat resistance improving layer, the above-mentioned problems could be solved.

According to a first aspect of the present invention, on the authenticity identification object, a heat resistance improving layer made of an ionizing radiation curable resin or a low-temperature-treated thermosetting resin and an optical diffraction on the surface of the authenticity identification object via an adhesive layer. The present invention relates to an authenticity discriminator having an authenticity discriminating structure characterized in that a cholesteric liquid crystal layer having fine irregularities of a structure is sequentially laminated.
The ionizing radiation curable resin is an electron beam curable resin or an ultraviolet curable resin, and the low-temperature treatment thermal effect resin is one that proceeds its heating and curing at a room temperature or a temperature of 50 degrees or less. The high temperature processing is not required.

According to a second aspect of the present invention, there is provided an authenticity identification structure according to the first aspect, wherein a protective layer is laminated on the opposite side of the cholesteric liquid crystal layer from which the heat resistance improving layer is laminated. It relates to an authenticity identifier.
According to a third aspect of the present invention, in the first or second aspect of the present invention, an authenticity identification body having an authenticity identification structure, wherein the authenticity identification object having the authenticity identification structure is an information recording medium. It is about.

According to a fourth aspect of the present invention, a transfer layer is laminated on a releasable surface of a releasable sheet-like substrate, and the transfer layer includes at least a protective layer and a release layer from the releasable sheet-like substrate side. A cholesteric liquid crystal layer having fine irregularities of a light diffraction structure on the surface opposite to the moldable sheet-like substrate side, a heat resistance improving layer made of an ionizing radiation curable resin or a low-temperature-treated thermosetting resin, and an adhesive layer are sequentially laminated. The present invention relates to an authenticity identification structure transfer sheet characterized by comprising the above structure.
The fifth invention relates to an authenticity identification structure transfer sheet according to the fourth invention, wherein a protective layer is laminated on the release sheet-like substrate side of the cholesteric liquid crystal layer.

  According to the first aspect of the present invention, the heat resistance of the cholesteric liquid crystal layer having fine irregularities such as holograms laminated on the authenticity identification object is made of an ionizing radiation curable resin or a low-temperature-treated thermosetting resin. Since the heat-improving layer is laminated, even when high temperature or high pressure is applied during transfer processing, fine irregularities such as holograms formed on the heat-resistant improving layer (depth 0.1 μm, period 1 μm or so) If there are fine fine irregularities, and even if these irregularities are slight, if they are deformed in conjunction with each other, an image such as a hologram is distorted and becomes undetectable when the hologram image is detected by a detector. The fine irregularities such as the hologram of the cholesteric liquid crystal layer in contact are difficult to disappear, and the authenticity identification function of the cholesteric liquid crystal layer having the fine irregularities such as the hologram is retained. It is possible to provide an authenticity identifier with improved durability against heat and pressure.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, since the protective layer is laminated on the side of the cholesteric liquid crystal layer without the fine irregularities, the physical and chemical properties of the surface of the authentic identification structure An authenticity identifier having high durability can be provided.
According to the invention of claim 3, in addition to the effect of the invention of claim 1 or claim 2, since the authenticity identification object is an information recording medium, the economic or social value possessed by the information recording medium Thus, it is possible to provide an authenticity identifier in which the authenticity of information having the above is ensured at a higher level.

According to the invention of claim 4, since the heat resistance improving layer is laminated on the fine irregularities of the cholesteric liquid crystal layer having fine irregularities such as holograms, if transfer is performed using this transfer sheet, In addition, it is difficult for the fine irregularities such as holograms to disappear, and the authentic identification function of the cholesteric liquid crystal layer having the fine irregularities such as holograms is retained, and thus the authenticity identification structure with improved tolerance of the authenticity identification function is achieved. It is possible to provide an authenticity identification structure transfer sheet that can be applied on an authenticity identification symmetric object.
According to the invention of claim 5, in addition to the effect of the invention of claim 4, an authenticity identification structure in which physical and chemical durability is improved by laminating a protective layer that can be the outermost layer after transfer. Can be provided on the authenticity-identifying symmetry object.

  FIG. 1 is a cross-sectional view of the authenticity identifier of the present invention. The authenticity identifier 1 of the present invention is basically a laminate in which an adhesive layer 3, a heat resistance improving layer 4, a cholesteric liquid crystal layer 5, and a protective layer 6 are sequentially laminated on an authenticity identification object 2. The cholesteric liquid crystal layer 5 has a structure, and has fine irregularities 5a having a light diffraction structure on the surface on the authenticity identification object 2 side.

The authenticity identification object 2 is the information recording medium or other various articles mentioned in the description of the prior art. Therefore, the material may be a composite made of plastic, cloth, paper, wood, leather, metal, stone, etc., or any combination thereof, depending on the article.
When the authenticity identification object 2 is an information recording medium, basically, paper, plastic, or a composite of paper and plastic is often used as a material. In the case of plastic alone, a plastic film, a plastic sheet, a single layer of a plastic plate, or a laminate of multiple layers can be used as a material.

Examples of the plastic include polyester such as polyvinyl chloride, polyethylene terephthalate (hereinafter may be abbreviated as PET) or polyethylene naphthalate, polycarbonate, polyamide, polyimide, cellulose diacetate, cellulose triacetate, polystyrene, acrylic, Examples of the resin include polypropylene, polyethylene, and ABS.

  A resin that does not contain chlorine and has excellent processability is preferably an amorphous polyester resin (for example, “PET-G” manufactured by Eastman Kodak Company). A blend resin of resin and polycarbonate resin is preferred. As this “PET-G”, for example, there is one in which the dicarboxylic acid component is terephthalic acid and the diol component is ethylene glycol / 1,4-cyclohexanedimethanol = 70/30 (mass ratio).

  When the authenticity identification object is a card such as a magnetic card, the thickness is preferably 0.76 mm. For example, a white plastic sheet having a thickness of 280 μm is used as a core sheet, and two sheets are stacked, and a transparent plastic sheet having a thickness of 100 μm is stacked on both sides as an oversheet, and laminated by hot pressing or the like ( A total thickness of 0.76 mm may be used.

When the authenticity identification object 2 is an information recording medium, usually various characters, designs, etc., or coloring may be applied by printing, coating, transfer, or the like. Taking a credit card as an example, the name of the card, the issuing company name, or the content itself may be a name often displayed by embossing, an item name of an expiration date, a notice, etc. As the symbol, there may be a symbol or a character characterizing the type of card.

  The adhesive layer 3 is made of vinyl chloride, vinyl acetate, vinyl chloride-vinyl acetate copolymer, acrylic, polyester, polyurethane, polyamide, or rubber-modified resin alone, or two or more kinds It is selected and used according to the material which comprises the heat-resistant improvement layer 4 and the authenticity identification target object 2 from the thing of a mixed system.

  As the cholesteric liquid crystal layer 5, it is possible to use any medium that exhibits optically selective reflectivity and circular polarization selectivity, such as a polymer film in which liquid crystal alignment is fixed, or a film in which cholesteric liquid crystal is dispersed in an appropriate resin. Although it is possible, a polymer film in which the liquid crystal alignment is fixed can be preferably used.

  Examples of the polymer film in which the liquid crystal alignment is fixed include a polymer film in which the low molecular liquid crystal is cholesterically aligned and then the low molecular liquid crystal is cross-linked by photoreaction or thermal reaction to fix the alignment. . As another example, a side chain type or main chain type thermotropic polymer liquid crystal was cholesterically aligned in a liquid crystal state and then cooled to a temperature below the liquid crystal transition point to fix the alignment state. A polymer film can be mentioned. Furthermore, a polymer film prepared by fixing the alignment state by gradually removing the solvent after cholesteric alignment of the side chain type or main chain type lyotropic polymer liquid crystal in a solution can also be used.

Examples of polymer liquid crystals that can be used for film production include side chain polymers such as polyacrylates, polymethacrylates, polysiloxanes, and polymalonates having liquid crystal forming groups in the side chains, and polyesters having liquid crystal forming groups in the main chain. , Main chain type polymers such as polyesteramide, polycarbonate, polyamide, and polyimide. If necessary, apply a cholesteric liquid crystal-containing ionizing radiation curable resin composition containing cholesteric liquid crystal in an ionizing radiation curable resin to an appropriate substrate, and irradiate the coating film with ionizing radiation. May be used. It can also comprise so that the base material when apply | coated may be peeled off.

  The cholesteric liquid crystal constituting the cholesteric liquid crystal layer has a regular twist so that the alignment structure of the liquid crystal molecules draws a spiral in the film thickness direction, and the pitch P of the spiral (necessary for rotating the liquid crystal molecules by 360 °) 2) of (1) selective reflectivity that strongly reflects light in a specific wavelength band of incident light, and (2) circular polarization selectivity. Shows two optical properties.

Since the selective reflectivity of (1) is limited to a specific wavelength range, the reflected light becomes a chromatic color with high color purity by appropriately selecting the pitch P of the cholesteric liquid crystal. Further, when the incident light is incident obliquely with respect to the normal line, the pitch P apparently decreases, so that the center wavelength λs shifts to the short wavelength side, and the bandwidth Δλ decreases. This phenomenon is called blue shift because the center wavelength λs shifts to the short wavelength side, and can be easily identified visually. For example, the reflected color of cholesteric liquid crystal that is colored red when observed from the normal direction (0 ° incidence position) is orange, yellow, green, blue-green, and blue as the viewing angle increases. Observe to change.

  The circularly polarized light selectivity of (2) refers to the property of reflecting only circularly polarized light in a specific rotational direction and transmitting circularly polarized light having the opposite rotational direction. Of the incident light, the circularly polarized light component in the same direction as the twist direction of the alignment structure of the cholesteric liquid crystal is reflected, and the rotational direction of the reflected light is also the same direction, while the circularly polarized light component rotating in the opposite direction is transmitted. Is a unique property unique to cholesteric liquid crystals. For example, in the case of a cholesteric liquid crystal having a right twist structure, right circularly polarized light is reflected, the reflected light remains right circularly polarized light, and left circularly polarized light is transmitted. Therefore, the cholesteric liquid crystal layer 5 is a layer that generates reflected light by reflecting only one of the left circularly polarized light and the right circularly polarized light in the incident light.

  In addition to the above two optical properties, the cholesteric liquid crystal layer 5 in the present invention has fine irregularities 5a of a light diffraction structure such as a hologram on the surface on the authenticity identification object 2 side. The shape of the fine unevenness 5a itself is obtained by phase-modulating each diffraction grating in an optical diffraction structure such as a hologram.

  FIG. 2 is a cross-sectional view for explaining the optical properties of the cholesteric liquid crystal layer 5 having the fine irregularities 5a of the present invention. Incident light I incident on the cholesteric liquid crystal layer 5 of the authenticity identifier 1 from a direction oblique to the normal (in the figure, a direction of about 40 ° with respect to the normal) is a protective layer of the cholesteric liquid crystal layer 5 Reflected light Ir is specularly reflected by the surface on the 6th side, and the circularly polarized light same as the reflected light Ir generates diffracted light Id in a direction different from the reflected light Ir due to the fine unevenness 5a. When the unevenness 5a is obtained by phase-modulating each diffraction grating in the hologram, a hologram image is generated.

  That is, the cholesteric liquid crystal layer 5 having the fine irregularities 5a of the present invention reflects only the left circularly polarized light or the right circularly polarized light on the surface on the protective layer 6 side and inside the cholesteric liquid crystal layer 5, and reflects it. Produce light. The circularly polarized light, which is the same as the reflected light, further reaches the fine unevenness 5a, and diffracted light Id in a direction different from the reflected light is generated in the fine unevenness 5a to form a hologram image.

  Therefore, when the reflected light Ir generated by the regular reflection of the incident light I on the surface of the cholesteric liquid crystal layer 5 on the protective layer 6 side is detected by using a detector, the incident light I passes through a circularly polarizing plate or is aligned with a linear polarizing plate. For example, when the cholesteric liquid crystal constituting the cholesteric liquid crystal layer 5 has a right-handed twisted structure through the phase difference film, if the right circularly polarizing plate is used, light is transmitted and detected by the detector, and the left circle If the polarizing plate is used, it is understood that the reflected light Ir is right circularly polarized light because the light is absorbed and the light is not detected by the detector.

Further, since the cholesteric liquid crystal layer 5 has selective reflectivity, it is possible to determine whether or not the cholesteric liquid crystal layer 5 has a reflection characteristic specific to the light source side or the detector side through a band pass filter that transmits a specific wavelength region. Yes.
Furthermore, the hologram image by the diffracted light Id diffracted in the direction different from the reflected light in the fine unevenness 5a can be detected using a detector.

The heat resistance improving layer 4 is laminated for the purpose of filling the fine irregularities 5a of the cholesteric liquid crystal layer 5 and eliminating the point where the fine irregularities 5a are easily lost by the heat and pressure applied to the cholesteric liquid crystal layer 5. With this lamination of layers, even if heat or pressure is applied to the cholesteric liquid crystal layer 5, the fine irregularities 5a do not disappear, and the heat resistance of the cholesteric liquid crystal layer 5 can be regarded as improved. In order to achieve this object, the heat resistance improving layer is preferably made of a material having higher heat resistance than the cholesteric liquid crystal layer 5. However, since the formation conditions of the heat resistance improving layer need to be such that the fine unevenness is not lost, the formation temperature is about room temperature or 50 ° C. or less.

The heat resistance improving layer 4 in this case is preferably made of a resin having a softening point higher than that of the cholesteric liquid crystal layer, but more realistically, the cholesteric liquid crystal layer 5 is 200. It is preferable that the resin does not lose the fine irregularities 5a of the cholesteric liquid crystal layer 5 even when the temperature reaches ℃.
Specific examples of the resin constituting the heat resistance improving layer 4 include a cured product of a thermosetting resin, and a cured product of an ionizing radiation curable resin. The ionizing radiation curable resin is an electron beam curable resin.

The thermosetting resin for constituting the heat resistance improving layer 4 includes urea resin, melamine resin, phenol resin, resorcinol resin, furan resin, epoxy resin, unsaturated polyester resin, polyurethane resin, polyimide, polyamideimide, polybenz Examples thereof include imidazole and polybenzothiazole.
As the ionizing radiation curable resin for constituting the heat resistance improving layer 4, ionizing radiation curable in which prepolymer, oligomer and / or monomer having a polymerizable unsaturated bond or an epoxy group is appropriately mixed in the molecule. It is preferable to use a resin composition. Ionizing radiation refers to electromagnetic waves or charged particle beams having energy quanta that can polymerize or crosslink molecules, and generally refers to electron beams.

Examples of prepolymers and oligomers in the ionizing radiation curable resin composition include unsaturated polyesters such as unsaturated dicarboxylic acid and polyhydric alcohol condensates, polyester methacrylate, polyether methacrylate, polyol methacrylate, melamine methacrylate, etc. Examples include methacrylates, polyester acrylates, epoxy acrylates, urethane acrylates, polyether acrylates, polyol acrylates, acrylates such as melamine acrylate, and cationic polymerization type epoxy compounds.

Examples of the monomer in the ionizing radiation curable resin composition include styrene monomers such as styrene and α-methylstyrene, methyl acrylate, 2-ethylhexyl acrylate, methoxyethyl acrylate, butoxyethyl acrylate, acrylic acid Acrylic esters such as butyl, methoxybutyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, methoxyethyl methacrylate, ethoxymethyl methacrylate, phenyl methacrylate, lauryl methacrylate, etc. Esters, 2- (N, N-diethylamino) ethyl acrylate, 2- (N, N-dimethylamino) ethyl acrylate, 2- (N, N-dibenzylamino) methyl acrylate, acrylic acid -2- (N, N-diechi Unsaturated substituted amino alcohol esters such as amino) propyl, unsaturated carboxylic acid amides such as acrylamide and methacrylamide, ethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol di Compounds such as acrylate, triethylene glycol diacrylate, polyfunctional compounds such as dipropylene glycol diacrylate, ethylene glycol diacrylate, propylene glycol dimethacrylate, diethylene glycol dimethacrylate, and / or two or more thiol groups in the molecule Polythiol compounds having, for example, trimethylolpropane trithioglycolate, trimethylolpropane trithiopropylate, pentaerythritol Examples include tetrathioglycolate.

Usually, as a monomer in an ionizing radiation curable resin composition, the above compounds are used alone or in combination of two or more as required. In order to give it, it is preferable that the prepolymer or oligomer is 5% by weight or more and the monomer and / or polythiol compound is 95% by weight or less.
When flexibility is required when the ionizing radiation curable resin composition is cured, it is preferable to reduce the amount of monomer or use an acrylate monomer having 1 or 2 functional groups. When wear resistance, heat resistance, and solvent resistance are required when the ionizing radiation curable resin composition is cured, an ionizing radiation curable resin is used such as using an acrylate monomer having three or more functional groups. A composition design is possible.

Here, 2-hydroxy acrylate, 2-hexyl acrylate, and phenoxyethyl acrylate are exemplified as those having one functional group. Examples of those having 2 functional groups include ethylene glycol diacrylate and 1,6-hexanediol diacrylate. Trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, having three or more functional groups
And dipentaerythritol hexaacrylate.
The heat resistance improving layer 4 is not limited in its hue, but has a light diffractive structure such as a hologram generated by the fine irregularities 5a of the cholesteric liquid crystal layer 5 when the dark color such as black is obtained by blending a dark dye or pigment such as black. It is preferable because visibility is increased. In addition, as thickness of the heat resistance improvement layer 4, 0.1 micrometer-5 micrometers are preferable, More preferably, it is about 0.5 micrometer-2 micrometers.

The protective layer 6 is laminated on the surface of the cholesteric liquid crystal layer 5 having the fine irregularities 5a opposite to the side where the fine irregularities 5a are present, and prevents the surface of the cholesteric liquid crystal layer 5 from being scratched or worn. It is provided for the purpose of improving the physical durability, or for the purpose of improving the chemical durability that protects from dirt, moisture, or various chemical substances. The protective layer 6 is not as effective as the heat resistant protective layer 5, but also has an effect of suppressing the disappearance of fine irregularities of the cholesteric liquid crystal layer 5 due to heat or pressure. Of course, it is not necessary to laminate the cholesteric liquid crystal layer 5 and the fine irregularities 5a of the cholesteric liquid crystal layer 5, but when the authenticity identifier 1 is used for a long period of time, it is laminated. Preferably it is.

  Examples of the material constituting the protective layer 6 include a cured product of a thermosetting resin or a cured product of an ionizing radiation curable resin, as in the case of forming the heat resistance improving layer 4 described above. Furthermore, a general thermoplastic resin can also be used, and the layer formation method is the same as in the case of the heat resistance improving layer 4. The thickness of the protective layer 6 is 0.1 μm to 10 μm, preferably about 0.5 μm to 5 μm.

  Examples of the thermoplastic resin that can constitute the protective layer 6 include rosin modified maleic acid resin, nitrocellulose, cellulose acetate, cellulose butylacetate, ethyl cellulose, saturated polyester resin, polyamide resin, chlorinated rubber, cyclized rubber, polyamide resin, polychlorinated resin. Mention may be made of vinyl resins, vinyl chloride / vinyl acetate copolymer resins, ethylene / vinyl acetate copolymer resins, chlorinated polypropylene or acrylic resins.

The authenticity identification body 1 of the present invention uses an authenticity identification object 2 as a base material, and an adhesive layer 3, a heat resistance improving layer 4, a cholesteric liquid crystal layer 5, and a protective layer 6 are sequentially laminated thereon. However, since it is necessary to form the fine irregularities 5a on the authentic identification object 2 side (also on the heat resistance improving layer 4 side) of the cholesteric liquid crystal layer 5, it is preferable to laminate them in the reverse order. .
Since the cholesteric liquid crystal layer 5 itself can also be obtained as a continuous film that can be wound, a protective layer 6 is laminated on one side of the cholesteric liquid crystal layer 5, and fine irregularities 5a are formed on the opposite side. A laminated body in which the heat resistance improving layer 4 and the adhesive layer 3 are laminated so as to cover the fine irregularities 5a is formed, and the obtained laminated body is used as an authenticity identification object 2 and an adhesive layer. Lamination can be performed by applying heat and pressure between the two so that the three sides become the authenticity identification object 2 side.

Or the laminated body which laminated | stacked the protective layer 6, the cholesteric liquid crystal layer 5 which has the fine unevenness | corrugation 5a in the heat resistance improvement layer 4 side, the heat resistance improvement layer 4, and the adhesive bond layer 3 is a transfer layer (it is also an authenticity identification structure). The transfer layer can also be laminated on the authenticity identification object 2 using the adhesive layer 3 by using such a transfer sheet.
FIG. 3 is a cross-sectional view showing an authenticity identification structure transfer sheet that enables transfer of such an authenticity identification structure. The authenticity identification structure transfer sheet 11 of the present invention has a protective layer 6, a cholesteric liquid crystal layer 5, and heat resistance on the release surface 12 a (the lower surface side in FIG. 3) on one surface of the release sheet upper substrate 12. The improvement layer 4 and the transfer layer 13 composed of the adhesive layer 3 are laminated in order, and the cholesteric liquid crystal layer 5 has a structure having fine irregularities 5a on the surface opposite to the releasable sheet-like substrate 12 side. Is.

As the releasable sheet-like substrate 12 which is a substrate sheet of a transfer sheet, polycarbonate, polyvinyl alcohol, polysulfone, polyethylene, polypropylene, polystyrene, polyarylate, polyethylene terephthalate, triacetyl cellulose, diacetyl cellulose, or polyethylene-vinyl alcohol A film of a resin such as a copolymer, which can be used as a base of a general transfer sheet, can be used with a thickness of about 2 to 100 μm, but may be outside this range. .
These plastic films are used in the form of a releasable surface by providing a releasable layer, if necessary, in relation to the material constituting the transfer layer 13, usually the protective layer 6. Further, the surface on which the protective layer 6 is formed has an appropriate release property, that is, has an appropriate adhesive force, but the transfer layer 13 can be peeled off smoothly in relation to the material constituting the protective layer 6. In the case of a releasable surface that can be carried out, it is used without providing a releasable layer.

The releasable layer provided for the purpose of imparting releasability to one side of the resin film is composed of a resin that adheres well to the resin film and provides an appropriate releasability surface, or such It is formed by adding a silicone resin, silicone oil, wax or the like to the resin for the purpose of improving peelability, and is usually formed to a thickness of about 1 to 5 μm.
A protective layer 6 is laminated on the releasable surface 12a of the releasable sheet-like substrate 12 described above. The materials to be used are as described above, and after preparing to have an appropriate viscosity suitable for application, it is applied by a known coating method, and the coated film after application is irradiated with ionizing radiation as necessary. The protective layer 6 can be laminated on the releasable surface 12 a of the releasable sheet-like substrate 12.

A cholesteric liquid crystal layer 5 is laminated on the surface of the protective layer 6 opposite to the releasable sheet-like substrate 12. In order to laminate the cholesteric liquid crystal layer 5, the materials described above may be used for lamination by applying and drying, or by separately laminating a separately produced cholesteric liquid crystal film using an adhesive or the like. You may laminate. Alternatively, the cholesteric liquid crystal layer may be laminated by coating using a cholesteric liquid crystal-containing ionizing radiation curable resin composition in which a cholesteric liquid crystal is blended in an ionizing radiation curable resin.

On the surface of the cholesteric liquid crystal layer 5 on the side opposite to the releasable sheet-like substrate side, fine irregularities 5a having a light diffraction structure such as a hologram are formed. In order to form the fine unevenness 5a, when the cholesteric liquid crystal layer 5 is thermoplastic, the cholesteric liquid crystal layer is pressed by pressing the uneven shape having a shape opposite to the desired fine unevenness 5a with heat and pressure. 5, it is preferable to form fine irregularities 5a having a light diffraction structure such as a hologram.
When the cholesteric liquid crystal layer 5 is formed using an ionizing radiation curable composition such as an ionizing radiation curable resin composition containing a cholesteric liquid crystal in which a cholesteric liquid crystal is blended in an ionizing radiation curable resin, a heat-resistant protective layer 5, the release sheet-like base material 12 laminated with the concave-convex mold is brought into intimate contact with such an ionizing radiation curable composition, and ionizing radiation is applied to the ionizing radiation curable composition as it is. The fine irregularities 5a can be formed by irradiating and curing.

When the protective layer 6 is composed of a cured product of an ionizing radiation curable resin and an ionizing radiation curable composition such as an ionizing radiation curable resin composition containing a cholesteric liquid crystal is used when forming the cholesteric liquid crystal layer 5. If the cholesteric liquid crystal layer 5 is to be formed after the protective layer 6 is completely cured, the adhesive force between the protective layer 6 and the cholesteric liquid crystal layer 5 may not be sufficiently improved. Accordingly, the curing of the protective layer 6 is still stopped in a half-cured state to such an extent that the adhesiveness of the surface is not lost, and the cholesteric liquid crystal-containing ionizing radiation curable resin is blended in the ionizing radiation curable resin. When an ionizing radiation curable composition such as a resin composition is applied on the protective layer 6 in a half-cure state, and the upper cholesteric liquid crystal layer 5 is cured while also serving as the curing of the lower protective layer 6, both layers It is preferable because it can be cured and sufficient adhesive strength between the two layers can be secured.

  The concavo-convex mold for forming the fine concavo-convex 5a may be planar or roller-shaped. The fine irregularities on one side of the concavo-convex type are produced as an original type obtained by phase-modulating a diffraction grating included in a hologram or a diffraction grating pattern (collectively referred to as an optical diffraction structure). For example, when a hologram is photographed, if a photoresist layer is subjected to interference exposure and developed, a relief type in which the grating is converted into irregularities can be obtained, so this can be made the original type. . In addition, when obtaining a hologram or diffraction grating pattern by calculation, a relief mold can be obtained by exposing and developing a photomask based on data obtained by converting phase information into mold depth information. This can be an original type.

  The obtained original mold is preferably a breeding plate so that the same fine irregularities can be pressed on a large area at a time by producing a replication mold by repeatedly performing plating or arranging them in the vertical and horizontal directions. Thus, it is used as a flat or roller-shaped uneven type. The heat resistance improving layer 4 is laminated so as to cover the side of the cholesteric liquid crystal layer 5 where the fine irregularities 5a are provided. In order to form the heat resistance improving layer 4 using a thermosetting resin, a main agent and a curing agent are mixed to prepare a thermosetting resin composition suitable for coating, and a cholesteric liquid crystal is formed by a known coating means. It apply | coats on the fine unevenness | corrugation 5a of the layer 5, and after application | coating, it heats and hardens as needed.

In order to form the heat resistance improving layer 4 using an ionizing radiation curable resin, a prepolymer,
After applying the ionizing radiation curable resin composition obtained by adding an oligomer and / or monomer, if necessary, with a photopolymerization initiator or a photopolymerization accelerator and mixing them, using a known coating means. This is done by irradiating the coating film with ionizing radiation. When the cholesteric liquid crystal layer 5 is composed of a cured product of an ionizing radiation curable resin, the cholesteric liquid crystal layer 5 serving as a lower layer during coating is half-cured to form ionizing radiation when forming the heat resistance improving layer 4. At the time of irradiation, the protective layer 6 and / or the cholesteric liquid crystal layer 5 serving as a lower layer may be completely cured. When both the protective layer 6 and the cholesteric liquid crystal layer 5 are made of a cured product of an ionizing radiation curable resin, both layers are in a half-cured state, and the ionizing radiation irradiation when forming the heat resistance improving layer 4 is performed. At this time, both the lower protective layer 6 and the cholesteric liquid crystal layer 5 may be completely cured.

Subsequently, the adhesive layer 3 is laminated on the heat resistance improving layer 4. As the material constituting the adhesive layer 3, the material already described is used, which is applied directly on the heat resistance improving layer 4 or laminated on a release paper (commonly called “separ paper”). It may be. This release paper is peeled off in advance when the authenticity identification structure is applied to the authenticity identification object.
The authenticity identification structure transfer sheet 11 is laminated with the adhesive layer 3 side facing the authenticity identification object 2 side, and the heat and pressure are applied by using a flat plate or roller-shaped hot press. By applying, the adhesive layer 3 is activated and bonded, and then the release sheet-like substrate 12 is peeled off, so that the light diffraction structure is formed on the surface opposite to the protective layer 6 and the protective layer 6 side from above. The authentic identification structure comprising the cholesteric liquid crystal layer 5 having the fine irregularities 5a, the heat resistance improving layer 4, and the adhesive layer 3 can be transferred onto the authentic identification object 2.

  Although the present invention basically has the above-described configuration, a layer that can be added in this field or a process may be added between the described layers. For example, corona discharge treatment for improving adhesion, lamination of an anchor layer or a primer layer, and the like. Further, in this specification, the release layer is in close contact with the plastic film, and it has been described with the intention of peeling between the release layer and the heat-resistant protective layer. A layer for adjusting the releasability may be added between the layers and the release layer may be separated. In addition, the authenticity identification body and the adhesiveness identification structure transfer sheet may be provided with an appropriately designed pattern or character as long as it can be seen from the outside, or may be colored. In particular, a colored layer, particularly a dark or dark colored layer, may be interposed between the adhesive layer 3 and the cholesteric liquid crystal layer 5.

The authenticity identification object 2 includes all of those listed in the prior art, but when the authenticity identification object 2 is an information recording medium that is highly likely to be used industrially, as described above. Of course, printing and embossing may be performed, but various elements, mainly information recording means, may be added depending on the application. Examples of such information recording means include magnetic recording layers, optical recording layers (including holograms), thermosensitive recording layers, thermosensitive decoloring layers, sublimation recording image receiving layers, and signature writable layers. Or an IC module or an LSI module. These may be added singly or in appropriate combination of two or more.

  (Example 1) An embossed hologram is formed on a cholesteric liquid crystal layer of a laminated film (manufactured by Mitsubishi Corporation, “CHS film”) in which a peelable protective layer and a cholesteric liquid crystal layer are laminated on a film having a release layer. Using the master mold, the unevenness of the hologram was formed using a press device comprising a heating roll and a pressure roll. Next, a black ink of a two-component curable polyurethane resin binder ("XEL detection mark black" / "XEL (D) cured by The Inktec Co., Ltd.") is formed on the entire surface on which the hologram unevenness is formed. Coating agent (isocyanate compound) = 100/5 mixture), the coating amount when dried is 1 g / m 2, and then aging is performed at a temperature of 50 ° for 36 hours to form a heat resistance improving layer. did.

  Further, an ink containing a vinyl chloride / vinyl acetate copolymer resin (“HS-ASV” manufactured by The Inktec Co., Ltd.) / “HS- 31 ”= 10/3 mixture), and the coating amount when dried was 3 g / m 2 to form a heat seal layer to obtain a transfer sheet. The transfer sheet obtained in this manner was stacked on a plastic card so that the heat seal layer side was in contact with it, thermally transferred under normal conditions, and when the film was peeled off, the hologram transferred onto the plastic card was sufficient. The hologram was not damaged by thermal transfer.

It is sectional drawing which shows an authenticity identification body. It is sectional drawing which shows the optical property of the cholesteric liquid crystal layer 5 of this invention. It is sectional drawing which shows an authenticity identification structure transfer sheet.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Authenticity identification body 2 Authenticity identification object 3 Adhesive layer 4 Heat resistance improvement layer 5 Cholesteric liquid crystal layer (5a; fine unevenness | corrugation)
6 Protective layer

Claims (5)

  On the authenticity identification object, a heat resistance improving layer made of an ionizing radiation curable resin or a low-temperature-treated thermosetting resin is provided on the authenticity identification object, and the surface on the authenticity identification object side has fine irregularities of a light diffraction structure. An authenticity identification body having an authenticity identification structure, wherein cholesteric liquid crystal layers are sequentially laminated.   The authenticity identification body having an authenticity identification structure according to claim 1, wherein a protective layer is laminated on the opposite side of the cholesteric liquid crystal layer from which the heat resistance improving layer is laminated.   3. The authenticity identification body having an authenticity identification structure according to claim 1 or 2, wherein the authenticity identification object having the authenticity identification structure is an information recording medium.   A transfer layer is laminated on the releasable surface of the releasable sheet-like base material, and the transfer layer includes a protective layer, a releasable sheet-like base material side, and a releasable sheet-like base material side. Has a structure in which a cholesteric liquid crystal layer having fine irregularities of a light diffraction structure on the opposite surface, a heat resistance improving layer made of an ionizing radiation curable resin or a low-temperature-treated thermosetting resin, and an adhesive layer are sequentially laminated. An authenticity identification structure transfer sheet characterized by: 5. The authenticity identification structure transfer sheet according to claim 4, wherein a protective layer is laminated on the releasable sheet-like substrate side of the cholesteric liquid crystal layer.

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