JP5278679B2 - Optical element seal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical element sticker excellent in the effect of an OVD (optically variable device), which facilitates determination of authenticity by visual check, the sticker capable of preventing from being reused by sticking after the sticker once stuck is peeled, and preventing an adhesive layer portion from remaining on the adherend when the sticker is peeled. <P>SOLUTION: The optical element includes an optical variable device (OVD) layer, a deformation layer and an adhesive layer, successively layered on one surface of a support, and includes a release layer partially between the support and the OVD layer. In the optical element, an adhesive force A between the adhesive layer and an adherend when the optical element is laminated to the adherend is greater than the adhesive force B between the support and the release layer portion. The OVD layer, the deformation layer and the adhesive layer deform by a force smaller than the adhesive force A, and the total fracture strength of the OVD layer, the deformation layer and the adhesive layer is greater than the adhesive force A. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an optical element seal using OVD whose color and image change depending on the direction of light including a hologram used for authentication of brand protection and the like.

  In recent years, multilayer thin films that can express stereoscopic images and special decorative images using light interference, and produce a color change (color shift) depending on the viewing angle by overlapping thin films with different holograms, diffraction gratings, and optical properties. Such an optical variable element (OVD) is being developed. These OVDs have an excellent decorative effect in order to give a unique impression such as a stereoscopic image and color shift, and have been used for general printed materials such as various packaging materials, picture books, catalogs, and the like.

  Further, since this OVD requires advanced manufacturing technology, it is formed and used as a part of or on the entire surface of credit cards, securities, certificates, etc. as effective forgery prevention means. Recently, in addition to securities, it is affixed to sports equipment, computer parts and other electrical product software, etc., as an authentication sticker that proves the authenticity of the product, and as a seal sticker that is affixed to the package of those products Has also become widely used.

  These authentication seals and seal seals are expected to be illegally reused after being peeled off and then replaced with a fake product. For this reason, brittle types that are destroyed when peeled have been proposed. For example, Patent Document 1 discloses a hologram label in which a volume hologram forming layer, a brittle layer, and an adhesive layer are sequentially formed. This is a configuration in which a brittle layer using a brittle material is provided in a part of the seal configuration, and when peeled off, the brittle layer breaks and remains on the adhesive layer (adhered body) side, and the hologram is destroyed. Further, Patent Document 2 discloses a configuration in which a part having strong adhesion and a part having weakness (peeling layer) are provided between the layers constituting the seal, and the part having weak adhesion peels off when peeled off. The hologram remains destroyed on the adhesive layer (adhered body) side.

  However, any of the above-described configurations is a configuration in which peeling or breakage occurs between layers or layers, and the seal is broken by separating it into the adhesive layer side and the support side. There was a drawback that the adhesive layer portion remained on the adherend and the adherend was soiled. In general, there are many high-value and high-value applications for authentication seals and seal seals, and dirt due to seal residues has been strongly demanded to improve the product value.

  On the other hand, in Patent Document 3, an OVD layer and an adhesive layer are laminated on a support with a deformable layer made of a polymer material having flexibility, and an interlayer adhesive strength between the support and the OVD layer is increased. An anti-replacement seal that is set to be greater than the adhesive strength of an adhesive layer to an adherend is disclosed. According to this, when the replacement is performed, the OVD layer constituting a part of the OVD layer is deformed into an unrecoverable state, and can be peeled from the adherend without leaving a part of the adhesive layer or the like. However, in this configuration, a thin OVD forming layer forming material formed so as to sandwich the deforming layer on the support is molded into a relief pattern by a roll embossing method or the like to form an OVD forming layer. Since the reproducibility of the relief pattern varies as a cushion, there is a problem that the optical effect of OVD cannot be fully exhibited.

Noto 2032258 Japanese Patent Laid-Open No. 08-152842 JP 2006-178277 A

  The present invention has been made in view of the above situation, has excellent OVD effect, facilitates visual judgment of authenticity, can prevent re-applying of a sticker once peeled off, It is an object to provide an optical element seal in which an adhesive layer portion does not remain on an adherend when peeled.

The invention according to claim 1 of the present invention is an optical element in which an optically variable element (OVD) layer, a deformation layer, and an adhesive layer are sequentially laminated on one side of a support, wherein the support and the OVD layer are An adhesive force A between the adhesive layer and the adherend when the optical element is bonded to the adherend has an adhesive force between the support and the peelable layer portion. B from rather large, adhesive force a of the adherend and the adhesive layer is an optical element seal being less than the adhesion C between the layers.

  In the invention according to claim 2 of the present invention, the OVD layer, the deformable layer, and the adhesive layer are deformed with a force smaller than the adhesive force A, and the OVD layer, the deformable layer, and the adhesive layer are deformed. 2. The optical element seal according to claim 1, wherein the total breaking strength is greater than the adhesive force A. 3.

  The invention according to claim 3 of the present invention is the optical element seal according to claim 1 or 2, wherein the deformable layer is made of a polymer material having a breaking elongation of 100% or more.

  The optical element seal of the present invention has a structure in which an OVD layer, a deformation layer, and an adhesive layer are sequentially laminated on one side of a support, and has a release layer in a part between the support and the OVD layer. The adhesive force A between the adhesive layer and the adherend when bonded to the adherend is greater than the adhesive force B between the support and the release layer portion. Therefore, if it tries to peel, since a deformation | transformation layer will elongate and it will produce a deformation | transformation, the OVD image of the part which provided the peeling layer will be destroyed, and the resticking use after peeling of the seal | sticker once stuck can be prevented. Since the deformed layer having a high cushioning property is applied after the OVD layer is formed and the OVD effect layer is formed, the reproducibility of a relief pattern such as a hologram is good without reducing the workability of the conventional OVD formation.

  In the optical element seal of the present invention, the OVD layer, the deformable layer, and the adhesive layer are deformed with a force smaller than the adhesive force A, and the total breaking strength of the OVD layer, the deformable layer, and the adhesive layer is greater than the adhesive force A. Since it is large, the OVD can be destroyed without separating the seal on the adhesive layer side and the support side. Therefore, the OVD can be destroyed at the time of replacement without leaving the adhesive layer on the adherend.

  Further, in the optical element seal of the present invention, the deformation layer is made of a polymer material having a relatively high breaking strength with a breaking elongation of 100% or more. Because it leaves traces of peeling, it is useful for verifying unauthorized use and preventing it.

Schematic which shows an example of the basic composition of the optical element seal | sticker of this invention in a cross section. The schematic diagram explaining destruction of OVD in the cross section at the time of peeling the optical element seal | sticker of this invention from a to-be-adhered body.

  An optical element seal of the present invention will be described below with reference to the drawings based on one embodiment.

  As shown in FIG. 1, the optical element seal 11 of the present invention comprises a support 1, a release layer 2, an OVD layer 3 composed of an OVD formation layer 31 and an OVD effect layer 32, a deformation layer 4, and an adhesive layer 5 sequentially laminated. It has become. The release layer 2 is smaller than the area of the OVD layer 3 and is partially formed.

  First, the mechanism of OVD destruction that occurs when the optical element seal of the present invention is peeled off from the adherend will be described. FIG. 2A is a schematic cross-sectional view showing a state in which the optical element seal is affixed to an adherend, and FIGS. 2B, 2C, and 2D show the state when the optical element seal is peeled off. It is the cross-sectional schematic explaining the destruction of OVD which arises.

  As shown in FIG. 2 (b), the part without the release layer 2 is peeled between the adhesive layer 5 and the adherend 6. Here, “adhesive strength between the adhesive layer and the adherend” A is “adhesive strength between the support and the OVD layer” C-1, “adhesive strength between the OVD layer and the deformable layer” C-2, and “deformation”. It is necessary to be smaller than the adhesive force C between the respective layers in “Adhesive force between layers and adhesive layer” C-3. That is, A <C.

  Next, as shown in FIG. 2C, in the portion where the release layer 2 is formed, “adhesive strength between the adhesive layer and the adherend” A is “adhesive strength between the support and the release layer portion” B. Since it is larger, peeling occurs between the support 1 and the release layer 2 before the adhesive layer 5 and the adherend 6 are peeled off. In this case, A> B.

  Next, as shown in FIG. 2D, when the adhesive layer 5 is peeled off from the adherend 6, the OVD layer 3, the deformable layer 4, and the adhesive layer 5 are deformed, and the OVD is destroyed. In this case, the OVD layer, the deformable layer, and the adhesive layer are required to have a capability of sufficiently deforming (extending) with a force smaller than the “force for peeling the adhesive layer from the adherend (ie, adhesive force A)”. In addition, “the sum of the breaking strengths of the OVD layer, the deformation layer, and the adhesive layer” D needs to be larger than the adhesive force A. That is, A <D.

That is, the conditions of the optical element seal of the present invention can be summarized in the following (1) to (4). By satisfying this condition, the OVD is destroyed when the optical element seal of the present invention is peeled off from the adherend by the above-described mechanism, and the adhesive layer is also adhered without separating the seal on the adhesive layer side and the support side. I will not leave it in my body.
(1) “Adhesive strength between adhesive layer and adherend” A> “Adhesive strength between support and release layer” B
(2) “Adhesive strength between adhesive layer and adherend” A <“Adhesive strength between layers” C
Here, C is “adhesive force between the support and the OVD layer” C-1, “adhesive force between the OVD layer and the deformable layer” C-2, and “adhesive force between the deformable layer and the adhesive layer” C-3. It is.
(3) “Adhesive strength between adhesive layer and adherend” A <“total breaking strength of OVD layer, deformable layer and adhesive layer” D
(4) “Force to peel adhesive layer from adherend (ie, adhesive force A)>“ Force to deform OVD layer, deformable layer, and adhesive layer ”

Here, the adhesive strength A is, for example, a T-type peeling at a speed of 100 ± 10 mm / min between the attached optical element seal of the present invention and the adherend under conditions of a temperature of 23 ± 2 ° C. and a relative humidity of 50 ± 5% Is a measured value. The adhesive strength B, adhesive strength C-1, adhesive strength C-2, and adhesive strength C-3 are determined by the presence or absence of delamination between the respective layers at the time of the T-type peeling, and the breaking strength D is the T-type. The magnitude of the adhesive strength A is determined based on whether or not the layer is broken at the time of peeling. Depending on the adherend to which the optical element seal of the present invention is applied and the use environment, the measurement conditions for the above-mentioned adhesive force A can be changed as appropriate. The optical element seal of the invention becomes possible.

Next, the configuration and materials of the optical element seal of the present invention will be described.

  The support 1 preferably has heat resistance and strength that is not softened and deformed by the heat pressure at the time of manufacturing the seal, and can be used that is less likely to be deformed as compared to the material of the deformation layer described later. As the material, one or more synthetic resins or natural resins selected from polyvinyl chloride, polyester, polycarbonate, polymethyl methacrylate, polystyrene, polyethylene, polyethylene terephthalate, polyethylene naphthalate, polypropylene, polyvinyl alcohol, etc. And a laminated sheet obtained by laminating these films. From the viewpoint of mechanical strength, heat resistance, dimensional stability and cost, a biaxially stretched polyethylene terephthalate (PET) film can be preferably used. The thickness is preferably about 16 to 50 μm in consideration of operability and workability.

The release layer 2 is partially formed on the support 1. As a material to be used, a material that can be easily peeled is used, and is appropriately selected based on the material used for the support. In addition, as conditions of the material used here, the above-mentioned (1) “adhesive strength between the adhesive layer and the adherend” A> “adhesive strength between the support and the release layer portion” B satisfies this condition. Is used. Furthermore, if the area where the release layer is provided is large, the force to peel off the adhesive layer and adherend corresponding to the area is applied to the OVD layer, the deformable layer, and the adhesive layer, and is easily broken. It is preferable. Although the design differs depending on the strength of each layer, the area is preferably 50% or less in total with respect to the support 1, and the pattern of each release layer is preferably 25 mm ² or less.

  Next, the OVD layer 3 will be described. OVD is an image using light interference and diffraction, and is a display body that causes a color shift in which the color changes depending on the representation of a stereoscopic image and the viewing angle. Of these, relief holograms (diffraction gratings) and multilayer thin film systems are generally widely used.

  An OVD layer 3 of the optical element seal of the present invention shown in FIG. 1 is a layer provided with a relief hologram (diffraction grating), and has a two-layer structure of an OVD formation layer 31 and an OVD effect layer 32. It has become.

  First, a relief hologram (diffraction grating) is produced by forming a fine uneven pattern of a hologram (diffraction grating) on the OVD forming layer 31 by hot pressure and replicating the pattern. This fine concavo-convex pattern is produced, for example, by producing a relief-type master plate having a fine concavo-convex pattern by an optical photographing method, and then replicating a nickel press plate by electroplating from this master plate, This press plate is heated and then pressed against the surface of the OVD forming layer. Therefore, thermoformability is required, and the above-mentioned condition (2) “Adhesive force between adhesive layer and adherend” A <“Adhesive force between support and OVD layer” C-1 is required. Therefore, a material that adheres sufficiently to the support 1 is used.

  Specific materials used for the OVD forming layer 31 include thermoplastic resins, thermosetting resins, ultraviolet rays or electron beam curable resins, and more specifically acrylic resins, epoxy resins, celluloses. Polyurethane added as a crosslinking agent to thermoplastic resins such as vinyl resins, vinyl resins, acrylic polyols and polyester polyols having reactive hydroxyl groups, and crosslinked urethane resins, melamine resins, phenol resins, etc. It is formed of a thermosetting resin, an ultraviolet ray such as epoxy (meth) acryl, urethane (meth) acrylate, or an electron beam curable resin, or a mixture thereof. These are dissolved in a solvent, or are applied and formed in a thickness of 3 to 10 μm on one side of a support without solvent and using a known coating method such as a gravure method.

The OVD effect layer 32 is made of a material having a refractive index different from that of the polymer material constituting the relief surface in order to increase the diffraction efficiency of the OVD image. As a material to be used, high refractive index materials such as TiO ₂ , Si ₂ O ₃ , SiO, Fe ₂ O ₃ , and ZnS having different refractive indexes, Al, Sn, Cr, Ni, Cu, and Au having a higher reflection effect are used. These materials can be used, and these materials can be used alone or in layers. These materials are formed by a well-known thin film forming technique such as vacuum deposition or sputtering, and the film thickness varies depending on the application, but is about 5 to 1000 nm. In addition to these methods, a method of coating a coating material in which metal flakes are dispersed is also provided, and the coating can be partially provided.

  On the other hand, a multi-layer thin film type OVD is composed of multi-layer thin film layers having different optical characteristics, and is laminated as a metal thin film, a ceramic thin film, or a composite thin film formed by combining them. For example, when thin films having different refractive indexes are stacked, a high refractive index thin film and a low refractive index thin film may be combined, or a specific combination may be stacked alternately. These are appropriately selected based on optical properties such as refractive index, reflectance, and transmittance, weather resistance, interlayer adhesion, and the like, and are laminated as a thin film to form a multilayer thin film. As a forming method, a normal vacuum deposition method or a sputtering method capable of controlling the film thickness, the film forming speed, the number of stacked layers, or the optical film thickness (= n · d, n: refractive index, d: film thickness), etc. Is formed.

  Next, the deformable layer 4 is a layer provided to deform when the optical element seal 11 is peeled off, and to destroy the OVD. Therefore, while it is desired to be sufficiently deformed, it must be designed so as not to be cut by the force of peeling. Condition (3) “Adhesive strength between adhesive layer and adherend” A <“Total breaking strength of OVD layer, deformation layer, and adhesive layer” D and Condition (4) “Adhesive layer from adherend It is necessary to use a material that satisfies the peeling force (ie, adhesive force A)> “force that deforms the OVD layer, deformable layer, and adhesive layer”. The deformable layer is a soft and tenacious material, and the stress obtained by stress-strain measurement -Strain curves with low modulus of elasticity and yield value or flat part and very large elongation are applicable. The elongation at break is at least 20% or more. Particularly, in order to ensure OVD fracture at the time of peeling of the optical element seal of the present invention, those having a break elongation of 100% or more are particularly preferable. Although the breaking strength depends on the performance of the other layers, those having a breaking strength of 30 Mpa or more are preferable. Examples of such a material that is sufficiently deformed and has a high breaking strength include a highly flexible polymer resin. Examples thereof include rubber resins such as natural rubber, isoprene rubber, styrene-butadiene rubber, and butyl rubber, and urethane resins. , Polyester resin, vinyl chloride-vinyl acetate copolymer and the like. Moreover, in order to make this layer difficult to break, it is preferable to provide a thickness of 2 to 50 μm.

  Next, the adhesive layer 5 is a layer for adhering and fixing the optical element seal to the adherend, and a known adhesive resin can be used. Agents are preferably used. Examples include natural rubber, isoprene rubber, styrene-butadiene rubber, rubber adhesives such as butyl rubber, acrylic adhesives such as ethyl acrylate and butyl acrylate, urethane adhesives, and the like. It consists of Further, this layer also needs to satisfy the above-mentioned condition (3) “Adhesive strength between adhesive layer and adherend” A <“total breaking strength of OVD layer, deformable layer and adhesive layer” D. It is necessary to select materials that are difficult to do.

  The above is the simplest configuration of the optical element seal of the present invention. This structure is a basic structure, and each layer is colored, or a printing layer is provided between the layers to improve the design, and it is possible to verify ultraviolet / infrared light emitting ink, infrared absorbing ink, etc. It is also possible to appropriately form a printing layer using anti-counterfeit ink and enhance the anti-counterfeit effect according to the purpose.

  Specific examples of the present invention will be described below.

<Example 1>
First, a release layer coating having the following composition was partially applied to a support composed of a transparent polyethylene terephthalate (PET) film having a thickness of 38 μm by a gravure method to form a release layer having a thickness of 0.5 μm. Next, an OVD forming layer paint having the following composition was applied by a gravure method to form an OVD forming layer having a thickness of 5 μm. Thereafter, an OVD relief pattern was formed by a roll embossing method, and an Al deposition thin film layer having a film thickness of 0.05 μm was provided thereon as a OVD effect layer by using a vacuum deposition method to form an OVD layer. Thereafter, a deformed layer paint having the following composition is applied on the Al vapor-deposited thin film layer using a comma coating method to form a deformed layer having a thickness of 10 μm. At the same time as forming the adhesive layer, release paper was laminated on the adhesive layer to produce the optical element seal of Example 1.
[Peeling layer paint]
-Acrylic resin 15 parts by mass-Methyl ethyl ketone 60 parts by mass-Toluene 25 parts by mass [OVD forming layer paint]
・ Vinyl chloride-vinyl acetate copolymer 15 mass parts ・ Urethane resin 10 mass parts ・ Methyl ethyl ketone 50 mass parts ・ Toluene 25 mass parts
[Deformation layer paint]
-Urethane resin (100% elongation at break) 10 parts by mass-Methyl ethyl ketone 60 parts by mass-Toluene 20 parts by mass
[Adhesive layer paint]
・ Acrylic adhesive 40 parts by mass ・ Isocyanate curing agent 5 parts by mass ・ Ethyl acetate 45 parts by mass ・ Toluene 10 parts by mass

<Comparative Example 1>
An optical element seal of Comparative Example 1 in which an OVD was formed by the same method as that of the same material except that the deformation layer by the deformation layer paint in Example 1 was removed was produced.

The optical element seal pieces according to Example 1 and Comparative Example 1 obtained as described above were each attached to a box (adhered body) made of an acrylic resin sheet, and an attempt was made to remove the seal. In addition, after sticking a sticker, it preserve | saved at normal temperature for 1 day, Then, the peeling test was done. Table 1 shows the results.

  As shown in Table 1, in the case of Example 1, the OVD was reliably destroyed due to the large deformation of the deformation layer. However, in Comparative Example 1, no deformation occurred, and the OVD could be peeled without being destroyed. It was.

  As described above, the optical element seal of the present invention has a structure in which the deformable layer extends and deforms when it is peeled off, and the OVD image is destroyed. Therefore, the seal is separated into the adhesive layer side and the support side. Therefore, the OVD can be destroyed without leaving the adhesive on the adherend.

DESCRIPTION OF SYMBOLS 1 ... Support body 2 ... Release layer 3 ... OVD layer 31 ... OVD formation layer 32 ... OVD effect layer 4 ... Deformation layer 5 ... Adhesion layer 6 Substrate

Claims (3)

An optical element formed by sequentially laminating an optically variable element (OVD) layer, a deformation layer, and an adhesive layer on one side of a support, having a release layer in a part between the support and the OVD layer, wherein said adhesive layer when the optical element bonded adherend adhesion a between the adherend is, the support and rather greater than the adhesive force B of the release layer portion, wherein said adhesive layer to be An optical element seal characterized in that the adhesive strength A of the adherend is smaller than the adhesive strength C between the respective layers .   The OVD layer, the deformable layer, and the adhesive layer are deformed with a force smaller than the adhesive force A, and the total breaking strength of the OVD layer, the deformable layer, and the adhesive layer is larger than the adhesive force A. The optical element seal according to claim 1.   The optical element seal according to claim 1, wherein the deformable layer is made of a polymer material having a breaking elongation of 100% or more.

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