JP6307817B2 - Fraud detection labels and labeled items - Google Patents

Description

  The present invention relates to a fraud detection label.

  The forgery prevention medium is used to prevent forgery of securities, branded products, certificates, personal authentication media, and the like, and has a function of proving that it is a genuine product.

  In recent years, since special optical effects can be distinguished at a glance, forgery prevention structures using optical elements such as diffraction gratings and holograms and special inks are used for various articles. The anti-counterfeit structure is manufactured in the form of an anti-counterfeit film, an anti-counterfeit sticker, an anti-counterfeit transfer foil, or the like, and is used by being attached to securities, brand products, certificates, personal authentication media, and the like.

  Many of these pasted anti-counterfeit structures have been subjected to measures for detecting fraud such as tampering and reuse.

  For example, Patent Document 1 proposes an anti-counterfeit sticker having a solvent coloring layer that develops color when the sticker is peeled off with various solvents. Moreover, in patent document 2, it has the peelable adhesive sheet for concealing a volume hologram layer, and the adhesive for adhere | attaching a volume hologram layer to a to-be-adhered body, The peeling strength between each laminated | stacked layers By adjusting the volume hologram layer, the volume hologram layer can be visually observed by re-peeling the label after bonding to the adherend, and the volume hologram layer having a volume hologram layer that cohesively breaks when attempting to peel the volume hologram layer. Labels have been proposed. Patent Document 3 proposes a hologram brittle seal in which a hologram layer or the like is laminated on a base material that has been partially surface-treated to improve adhesion, and the hologram layer is partially peeled and broken when peeling is attempted. ing.

JP 2009-134528 A Patent No. 4097128 Japanese Patent No. 3684653

  However, in the sticker of Patent Document 1, when the solvent coloring layer is peeled off or dissolved and removed, there is no history of the sticker being peeled off by the solvent. In other words, when the optical element such as the diffraction grating or the hologram or the portion holding the special ink is taken out without being damaged, there remains a problem that the sticker is illegally reused.

  In addition, the labels and seals of Patent Document 2 and Patent Document 3 provide a sufficient effect when physical peeling is attempted, but the effect is sufficient for the method of dissolving the adhesive layer using a solvent. is not.

  The present invention has been made paying attention to the above circumstances, and it is an object of the present invention to provide a fraud detection label that can easily detect fraudulent use that is reused after the label attached to the article has been peeled off once. And

The invention according to claim 1 of the present invention is a fraud detection label having an optically variable layer on one surface of a substrate and an adhesive layer on the other surface,
The optical change layer is formed from a composition for forming an optical change layer comprising a mixed resin of a first resin and a second resin having a number average molecular weight of 2.5 to 5 times that of the first resin, and a solvent,
The form of the optically variable layer is divided into two regions, a first region and a second region having a visible light transmittance of 5% or more lower than the first region,
In addition, when the optically changing layer is in contact with the solvent that dissolves at least one of the first and second resins and the entire region of the optically changing layer is the third region, the third region is in contact with the solvent. It is a fraud detection label characterized by showing a higher visible light transmittance than the previous second region.

In the invention according to claim 2, the first region is a region where the first resin and the second resin are in a compatible state,
The fraud detection label according to claim 1, wherein the second region is a region where the first resin and the second resin are in an incompatible state.

In the invention according to claim 3, the blending ratio (in terms of mass) of the first resin in the mixed resin is such that the mixed resin shifts from compatible to incompatible with the unit mass of the solvent. When the critical ratio of the first resin is C1 (%), is it in the range of C1 (%) to C1-10 (%),
Alternatively, when the critical ratio of the first resin at the time of transition from incompatible to compatible is C2 (%), the range is from C2 (%) to C2 + 10 (%). Or it is the fraud detection label of 2.

  The invention according to claim 4 is the fraud detection label according to any one of claims 1 to 3, wherein the number average molecular weight of the first resin is in the range of 50,000 to 100,000. It is.

  Further, in the invention according to claim 5, the optically changeable layer is formed so that the third region is in contact with the solvent from a state in which the first region is transmissive and the second region is impermeable. The fraud detection label according to any one of claims 1 to 4, wherein the fraud detection label exhibits transparency.

  The invention according to claim 6 is the fraud detection label according to any one of claims 1 to 5, wherein the first resin is a cellulose derivative.

  The invention according to claim 7 is the fraud detection label according to any one of claims 1 to 6, wherein a coating layer is laminated on at least a part of the optically variable layer.

  The invention according to claim 8 is an article with a label, wherein the fraud detection label according to any one of claims 1 to 7 is pasted through the adhesive layer.

  According to the first aspect of the present invention, in the mixed resin contained in the optically variable layer forming composition, the difference between the number average molecular weight of the first resin and the number average molecular weight of the second resin is 2.5. By making it 5 times, a big difference arises in the melt | dissolution rate of said two resin with respect to a solvent, and it will be in an incompatible state. As a result, when the composition for forming an optically variable layer is applied and dried to form the optically variable layer, a mottled pattern can be developed due to a difference in visible light transmittance due to a difference in light scattering.

In addition, a mottled pattern is formed in the optically changing layer between the first region and the second region having a visible light transmittance of 5% or more lower than that of the first region, so The entire region (third region) can exhibit a higher visible light transmittance than the second region before immersion in the solvent.

  That is, using the label on which the optically changing layer is formed, the form change before and after the solvent immersion with respect to the label can be easily confirmed visually.

According to claim 1 , the first region is a region where the first resin and the second resin are in a compatible state, and the second region is a phase where the first resin and the second resin are out of phase. By being in a molten state, the optically variable layer can be easily mottled .

According to claim 2 , the blending ratio (in terms of mass) of the first resin in the mixed resin is determined when the mixed resin shifts from compatible to incompatible with the unit mass of the solvent. When the critical ratio of the first resin is C1 (%), the range is from C1 (%) to C1-10 (%), or the first resin is changed from incompatible to compatible. When the limit ratio is C2 (%), the optical change layer can be easily mottled by setting the range from C2 (%) to C2 + 10 (%).

According to claim 3 , by setting the number average molecular weight of the first resin in the range of 50,000 to 100,000, the number average molecular weight of the second resin is 10,000 to 500,000. The selection range of the resin and the second resin is widened, and the design of the composition for forming an optically variable layer is facilitated.

Further, according to claim 5 , by using the first resin as a cellulose derivative, the resin generally used for the adhesive layer is set to a value close to the solubility parameter (δ) of a solvent that easily dissolves and swells. And the dissolution of the mixed resin can be facilitated.

  According to the present invention, the mottled optically changing layer can be provided with a label capable of fraud detection because the entire layer exhibits uniform permeability after being immersed in the solvent. In addition, by attaching the label of the present invention to an article, it is possible to easily detect whether or not peeling with a solvent has been attempted, and reuse and tampering can be prevented in advance.

It is sectional drawing which shows schematically the fraud detection label which concerns on the 1st Embodiment of this invention. It is the top view which looked at the label shown in FIG. 1 from the front side. It is the top view which looked at the state after immersing and drying the label shown in FIG.1 and FIG.2 in the solvent from the front side. It is sectional drawing which shows schematically the fraud detection label which concerns on the 2nd Embodiment of this invention. It is the top view which looked at the label shown in FIG. 4 from the front side. It is the top view which looked at the state after immersing and drying the label shown in FIG.4 and FIG.5 in the organic solvent from the front side. It is sectional drawing which shows schematically the fraud detection label which concerns on the 3rd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In addition, the same referential mark is attached | subjected to the component which exhibits the same or similar function through all the drawings, and the overlapping description is abbreviate | omitted.

FIG. 1 is a cross-sectional view schematically showing a label according to the first embodiment of the present invention. FIG. 2 is a plan view of the label shown in FIG. 1 as seen from the front side, that is, the observer side. FIG. 3 is a plan view showing an example of a state after the label shown in FIGS. 1 and 2 is immersed in a solvent. The label according to the first embodiment is a label having the most basic configuration of the present invention. A label 10 shown in FIG. 1 includes a label substrate 2, and an optically changing layer 1 is provided on one surface thereof, and an adhesive layer 8 is provided on the other surface.

  The substrate 2 that can be used in the present invention is preferably a plastic film, and examples thereof include PET (polyethylene terephthalate), PEN (polyethylene naphthalate), and PP (polypropylene). Depending on the application and purpose, paper, synthetic paper, plastic multilayer paper, resin-impregnated paper, or the like can be used as a substrate. However, it is preferable to use a material that is less deformed or deteriorated due to heat, pressure, or the like when the optically changing layer 1 is provided. The optical change layer 1 is not necessarily provided so as to be in direct contact with the base material 2, and an intermediate layer or the like (not shown) may be provided between the base material 2 and the optical change layer 1.

  The adhesive layer 8 is for attaching the label 10 to an article. The adhesive layer 8 can be formed of an adhesive mainly composed of polyester resin, urethane resin, acrylic resin, vinyl chloride resin, or the like. The adhesive layer 8 can be formed by a known method such as a gravure printing method or a screen printing method.

  The optically variable layer 1 is composed of a composition for forming an optically variable layer containing a mixed resin of a first resin and a second resin, which have greatly different number average molecular weights, and a solvent, and the number average molecular weight of the second resin is the first. 2.5 to 5 times the resin is preferable.

  Further, the optically changing layer 1 has a mottled pattern in which the first region 3 and the second region 4 having a visible light transmittance of 5% or more are mixed (FIG. 2).

  Also, as shown in FIG. 3, after the optical change layer 1 is immersed in a solvent capable of dissolving at least one of the first and second resins, the entire region (third region 5) of the optical change layer 1 is obtained. ), The mottled pattern disappears, and uniform transmittance with a value higher than the visible light transmittance of the second region is exhibited. Here, immersing in a solvent is assumed to be an action in which the label 10 of the present invention having the optical change layer 1 is attached to an article and then immersed in a solvent to peel off the label 10.

  As described above, the fraud detection label 10 of the present invention has the optically changing layer 1 formed on one surface of the base material 2 shown in FIG. A mottled pattern caused by the difference in visible light transmittance with the region 4 is exhibited. And when this label 10 is immersed in the solvent which melt | dissolves one of 1st resin or 2nd resin, as shown in FIG. 3, said mottled pattern will lose | disappear and the optical change layer 1 whole (3rd area | region 5). ) Exhibits uniform permeability. Such a change in the state of the optically variable layer 1 before and after immersion in the solvent can be easily confirmed visually, and unauthorized use of the label 10 can be detected.

  Note that the mottled pattern generated by the difference in the visible light transmittance between the first region 3 and the second region 4 has a visible light transmittance of 5% or more in the second region 4 than the visible light transmittance in the first region 3. Preferably it is low. If the difference in visible light transmittance between the two regions is 5% or less, it is difficult to visually confirm the mottled pattern.

  In order to make it easier to visually confirm the state change from the mottled pattern before the solvent immersion by the first region 3 and the second region 4 to the uniform permeability of the third region after the solvent immersion. For example, the first region 3 before the solvent immersion is transparent, the second region 4 is opaque, and the third region 5 after the solvent immersion is highly transparent (transparent). Specifically, it is control of the compatibility of the first resin and the second resin forming the optically variable layer 1 with respect to the solvent, and the produced label is incompatible before the solvent immersion, and is compatible after the solvent immersion. To change. That is, it becomes possible by controlling the blending ratio of the mixed resin in the optical change layer forming composition for forming the optical change layer 1.

  Here, that the first resin and the second resin are “compatible” means that a mixed resin solution obtained by dissolving or dispersing a mixed resin of the first resin and the second resin in an organic solvent, or the mixed resin solution. The mixed resin solid material obtained by drying means a state that does not have light scattering properties and is transparent. The visual turbidity method is simple and reliable for determining whether the mixed resin solution or the mixed resin solid is compatible or incompatible. For example, when the mixed resin solution (the composition for forming an optically variable layer) containing the first and second resins is transparent, or when the film prepared by drying the mixed resin solution is transparent, both resins Can be determined to be compatible.

  In the case of visual observation, in the present invention, the resolution of the human eye is considered to be as large as the wavelength of visible light (about 500 nm). That is, when transparent, it is guaranteed that the concentration and composition are uniform, that is, compatible even at wavelengths longer than the visible light wavelength. On the other hand, when the mixed resin solution or the mixed resin solid is opaque, it is determined that the sample is incompatible. The reason for becoming opaque is that the concentration and composition are not uniform because the first and second resins are incompatible.

  When the optically variable layer 1 is formed in a state where the first resin and the second resin are not compatible, that is, the blending ratio of the first resin and the second resin locally in the optically variable layer 1 When the balance is lost and the two resins are incompatible with each other and are opaque in the local region and formed with a mottled pattern as a whole, the optically changing layer 1 has the above solvent with respect to the label 10. In the process where the solvent comes into contact with the solvent and is volatilized, the balance of the mixing ratio of the first resin and the second resin, which are incompatible, is relaxed, and the compatible state Thus, a state transparent to visible light appears.

  A difference in the number average molecular weight between the first and second resins affects one factor for causing such a phenomenon. That is, when the difference in number average molecular weight is small, the difference in the dissolution rate of each resin with respect to the solvent is small, the balance of the blending ratio of the first resin and the second resin is locally broken, and both resins are in an incompatible state. However, in the process from solvent contact to volatilization, the balance of the blending ratio of the first resin and the second resin is relaxed, and it is likely to be in a compatible state. Conversely, when the difference in number average molecular weight is large, the difference in the dissolution rate of each resin in the solvent is large, and a mottled pattern that becomes incompatible is likely to appear, but in the process from solvent contact to volatilization. The balance of the blending ratio of the first resin and the second resin is not easily relaxed, and it is difficult to achieve a compatible state.

  Furthermore, in a preferred embodiment, the ratio (mass%) of the first resin in the mixed resin composed of the first resin and the second resin is a content ratio at which these mixed resins are incompatible with each other. When the ratio is increased to a range from C1 (%) to C1-10 (%) of the first resin changing from compatible to incompatible, or these mixed resins are incompatible It is preferable that it is in the range from the critical ratio C2 (%) to C2 + 10 (%) of the first resin that changes from to compatible.

  The number average molecular weight of the first resin is preferably 50,000 to 100,000, and the number average molecular weight of the second resin is preferably 10,000 to 500,000. If the number average molecular weight is in this range, the first resin and the first resin The selection range of the two resins is widened, and the design of the composition for forming an optically variable layer is facilitated.

  Specifically, for example, a cellulose derivative such as “Celnova BTH1 / 2” nitrocellulose (NC) resin (number average molecular weight 70,000) manufactured by Asahi Kasei Kogyo Co., Ltd. can be used as the first resin. Further, as the second resin, “Dianar BR-118” acrylic resin (number average molecular weight 190,000) manufactured by Mitsubishi Rayon Co., Ltd. can be used. Here, the number average molecular weight can be measured by an osmotic pressure method, a viscosity method, a light scattering method, or the like.

  By the way, the dissolution rate of a resin in a certain organic solvent is mainly determined by the number average molecular weight of the resin, but is known to depend on crystallinity, polarity and solubility parameters.

  In general, a resin material having a high number average molecular weight has a low dissolution rate, and a resin material having a low number average molecular weight has a high dissolution rate. For example, in a chain polymer (resin), the longer the molecular chain (the higher the number average molecular weight), the greater the attractive force between the polymer molecules, making it difficult to disentangle and disperse the molecular chain from the solvent molecules. In addition, the attractive force between polymer molecules increases as the surface where the polymer molecules contact each other, that is, as the polymer molecule orientation is ordered (crystalline). Therefore, in a chain polymer, the higher the number average molecular weight (degree of polymerization) and the higher the ratio of crystallinity, the more difficult it is to dissolve in the solvent.

Another factor that determines the solubility of the resin is its affinity with solvent molecules. For example, polar polymers tend to be soluble in polar solvents and tend not to dissolve in nonpolar solvents, and nonpolar polymers tend to be reversed. A factor for determining the strength of the affinity is a solubility parameter (SP value) δ. This δ value is expressed by the following formula. In principle, the closer the δ value between the polymer and the solvent molecule, the higher the solubility.
δ ² = ΔE / V
Here, ΔE is the evaporation energy and V is the molar volume.

  That is, in order to increase the dissolution rate in a certain solvent A, a resin having a solubility parameter close to that of the solvent A may be selected. On the other hand, in order to decrease the dissolution rate in the solvent A, the solubility parameter is different from that of the solvent A. What is necessary is just to select resin.

  For example, main δ values of resin materials include vinyl acetate (9.1), polymethyl methacrylate (9.2), vinyl chloride (9.3), vinyl acetate (9.4), nitrocellulose (10.1). ), Methacrylate resin (10.7), cellulose acetate (11), cellulose diacetate (11.4), polystyrene (8.6 to 9.7) and the like are disclosed in known literatures. Further, as main δ values of the solvent, cyclohexane (8.2), butyl acetate (8.5), toluene (8.9), ethyl acetate (9.1), methyl ethyl ketone (9.3), tetrahydrofuran (9 .5), acetone (10), ethyl alcohol (12.7), water (23.4) and the like are disclosed in known literatures.

  As described above, the solvent capable of dissolving at least one of the first and second resins corresponds to a solvent capable of dissolving or swelling the adhesive layer 8 so that the label 10 can be peeled from the article in the adhesive layer 8. Usually, such a solvent is an organic solvent and can dissolve both the first and second resins, regardless of the difference in dissolution rate. Examples of such a solvent include acetone, methyl ethyl ketone, ethyl acetate, ethyl alcohol, benzene, toluene, perchlorethylene, or a mixture thereof.

  When the label 10 of the present invention is immersed in the above-mentioned solvent and then dried, the optically variable layer 1 changes as shown in FIGS. That is, as shown in FIG. 2, the first region 3 and the second region 4 before the solvent immersion have a visible light transmittance difference of 5% or more between the two regions, so that a mottled pattern can be visually confirmed. Moreover, as shown in FIG. 3, after the solvent immersion, the entire region (third region 5) shows uniform permeability, and the difference in the optically changing layer 1 before and after the solvent immersion can be easily confirmed visually. , Can detect unauthorized use of labels.

Thus, the optically variable layer 1 appropriately selects the difference between the number average molecular weights of the first and second resins, the resin ratio that is compatible and incompatible, the dissolution rate, the crystallinity, the polarity, the solubility parameter, and the solvent. Thus, the optically variable layer 1 is formed in an incompatible state and can be in a compatible state when the resin is re-dissolved with a solvent (solvent immersion). The optical change layer 1 can be formed by a known printing technique such as gravure printing, flexographic printing, screen printing, or offset printing, but is not limited thereto.

  FIG. 4 is a cross-sectional view schematically showing a label according to the second embodiment of the present invention. FIG. 5 is a plan view of the label shown in FIG. 4 as viewed from the front side. FIG. 6 is a plan view showing an example of a state after the labels shown in FIGS. 4 and 5 are immersed in an organic solvent.

  The label 11 shown in FIG. 4 is provided on the printing layer 6 provided partially and on the entire surface in addition to the optical change layer 1 provided partially, the base material 2 and the adhesive layer 8 made of a transparent material. The optical reflection layer 7 is included. Typically, the optically changing layer 1 is provided so as not to overlap the printed layer 6, and the optical reflecting layer 7 is interposed between the substrate 2 and the adhesive layer 8.

  The print layer 6 is a layer that is provided in an arbitrary color and in the form of a pattern such as letters and pictures in order to give information to be transmitted. The printing layer 6 is formed using, for example, ink. As this ink, offset ink, letterpress ink, gravure ink and the like can be used depending on the printing method, and for example, resin ink, oil-based ink and water-based ink can be used depending on the difference in composition. Further, depending on the difference in the drying method, for example, an oxidation polymerization type ink, a permeation drying type ink, an evaporation drying type ink, and an ultraviolet curable ink can be used.

  Moreover, as the printing layer 6, you may use the functional ink from which a color changes according to the illumination angle or observation angle of light. Examples of such functional inks include optically variable ink, color shift ink, and pearl ink.

  Alternatively, the printing layer 6 may be formed by electrophotography using toner. In this case, for example, a toner is prepared in which colored particles such as graphite and pigment are adhered to plastic particles having charging properties. The printed layer can be formed by transferring the toner to the base material by using static electricity caused by charging, and heating and fixing the toner.

  Further, a diffractive structure forming layer or a holographic image forming layer may be provided as the printing layer 6 to give information by diffracted light or a hologram image.

The optical reflection layer 7 is a layer provided for easily observing the mottled pattern formed on the optical change layer 1. Examples of materials that can be used include materials having a high refractive index such as TiO ₂ , Si ₂ O ₃ , SiO, Fe ₂ O ₃ , and ZnS, or Al, Sn, Cr, Ni, Cu, and the like that have a high light reflection effect. A metal material such as Au can be used. The film thickness is preferably 10 to 500 nm, and a forming method such as a vacuum evaporation method or a sputtering method is used.

  The optical reflection layer 7 may be provided on the entire surface, or may be partially provided so as to correspond to the shape of characters, pictures, and the like. When it provides partially, since design property improves and processing becomes complicated, it becomes possible to provide a higher forgery prevention effect.

As a method of partially providing the optical reflection layer 7, a method in which an optical reflection layer is provided after a soluble resin is partially formed, and the soluble resin and the optical reflection layer in that portion are washed and removed. A metal thin film layer is used as the reflective layer, and after the metal thin film layer is partially provided using an acid-resistant or alkali-resistant resin, the metal thin film is dissolved by acid or alkali, or by light exposure. Alternatively, after applying a resin material that is difficult to dissolve and exposing through a mask having a desired pattern, unnecessary portions are removed by washing or etching. The above is an example, and the method of forming the optical reflection layer is not limited to these, and a known technique can be used as appropriate.

  A label 11 shown in FIG. 5 shows a state before being immersed in an organic solvent, and a label 11 shown in FIG. 6 shows a state after being immersed in an organic solvent.

  In the label 11 shown in FIG. 5, the optically changing layer 1 is partially provided. In the partially provided optically changing layer 13, the first region 3 and the visible light transmittance are thereby reduced. The second region 4 lower by 5% or more is partially formed and has a mottled pattern. Further, the base material 2 has a visible light transmission property, and a star pattern formed by the printing layer 6 and the characters “TOPPN PRINTING” can be observed. it can.

  In the label 11 shown in FIG. 6, the mottled pattern disappears from the partially provided optical change layer 13 and is changed to the transparent third region 5. In the label 11 of FIG. 6, it can be easily confirmed visually that the mottle pattern disappears and a clear change occurs compared to the label 11 of FIG. 5.

  FIG. 7 is a cross-sectional view schematically showing a fraud detection label according to the third embodiment of the present invention. The label 12 shown in FIG. 7 includes a coating layer 9 in addition to the optically changing layer 1, the base material 2, the adhesive layer 8, the printing layer 6, and the optical reflecting layer 7 provided on the entire surface or a part thereof. The label 12 in FIG. 7 has a configuration in which a coating layer 9 is further provided on the top of the label 11 in FIG.

  The covering layer 9 needs to be made of a material that dissolves or permeates the organic solvent in a solvent that changes the optically changing layer 1 from a mottled pattern to a transparent state. For example, when the solvent is a methyl ethyl ketone / toluene mixed solvent, materials that can be selected as the coating layer 9 are acrylic resin and cellulose acetate butyrate resin that can be dissolved in the methyl ethyl ketone / toluene mixed solvent or permeate the methyl ethyl ketone / toluene mixed solvent. Is mentioned.

  By using a coating layer, it is possible to enhance the physical properties such as surface resistance and durability of the label according to the application and purpose, while maintaining the function when the label is peeled off using a solvent. It is. It is also possible to adjust the physical strength and surface friction coefficient of the layer by appropriately adding additives such as filler and wax to the coating layer.

  Although the label according to the embodiment of the present invention has been described in detail above, other processes and configurations are possible. For example, in order to improve the adhesion between the respective layers, corona treatment, plasma treatment and / or primer coating may be performed. Furthermore, in order to improve the designability, it is possible to color each layer, or to form a multilayer interference film by forming a multilayer optical reflection layer. Moreover, the structure etc. which incorporated the inlet with an IC chip are also possible.

  Hereinafter, the present invention will be described in detail with specific examples. In the following examples, “part” means mass part, and “ratio” means mass ratio.

<Example 1>
A transparent PET film having a thickness of 50 μm was used as the label substrate 2, and an ink composed of the following composition was partially provided on one side by a screen printing method to form a printing layer 6.

<Print layer ink>
(Yellow ink for graphics)
High molecular methacrylic (PMMA) resin 2 parts Low viscosity nitrocellulose 12 parts Yellow pigment 3 parts Cyclohexanone 10 parts.
(Black ink for characters)
High molecular methacrylic (PMMA) resin 2 parts Low viscosity nitrocellulose 12 parts Carbon black 3 parts Cyclohexanone 10 parts.

  Next, a composition for forming an optical change layer shown below for forming the optical change layer 1 is formed on the surface of the substrate 2 on the side where the print layer 6 is formed by a gravure printing method. It formed so that it might become.

<Composition for optical change layer formation>
Acrylic resin (Dyanal BR-118 number average molecular weight 190,000) 0.45 parts Nitrocellulose (Celnova BTH1 / 2 average molecular weight 70,000) 0.55 parts Acetone / toluene (ratio 1/1) mixed solvent 10 parts

  Thereafter, aluminum was formed on the other surface of the substrate 2 as the optical reflection layer 7 so as to have a film thickness of 50 nm by vacuum deposition. Furthermore, as the adhesive layer 8, an ink made of the following composition was provided on the entire surface by a gravure printing method so as to have a thickness of 10 μm, and a label 11 shown in FIGS. 4 and 5 was obtained.

<Adhesive layer composition>
Polyester adhesive 40 parts Ethyl acetate 60 parts.

<Example 2>
Except that the coating layer 9 was formed on the entire surface of the optically variable layer 1 so as to have a thickness of 1.2 μm by a gravure printing method using a coating layer forming composition having the following composition, the same as in Example 1. The label 12 shown in FIG.

<Composition for forming coating layer>
Acrylic resin 10 parts (Methyl ethyl ketone / toluene mixed solution, ethyl acetate, perchlorethylene soluble)
Polyethylene wax 0.5 part Methyl alcohol 90 parts

<Comparative Example 1>
A label was produced in the same manner as in Example 1 except that the composition for forming an optically variable layer comprising the following composition was used.

<Composition for optical change layer formation>
Acrylic resin 0.45 parts (Dianal RB-52, number average molecular weight 850,000)
Nitrocellulose 0.55 parts (Sernova BTH1 / 2, number average molecular weight 70,000)
10 parts of acetone / toluene (ratio 1/1) mixed solvent

<Comparative example 2>
A label was produced in the same manner as in Example 1 except that the composition for forming an optically variable layer comprising the following composition was used.

<Composition for optical change layer formation>
Acrylic resin 0.65 parts (Dianal RB-79, number average molecular weight 70,000)
Nitrocellulose 0.35 parts (Sernova BTH1 / 2, number average molecular weight 70,000)
Acetone / toluene (ratio 1/1) mixed solvent 10 parts

<Comparative Example 3>
A label was produced in the same manner as in Example 1 except that the composition for forming an optically variable layer comprising the following composition was used.

<Composition for optical change layer formation>
0.45 part of polyester resin (manufactured by Unitika Ltd., Eritail UE3201, number average molecular weight 10,000)
Nitrocellulose 0.55 parts (Sernova BTH1 / 2, number average molecular weight 70,000)
Acetone / toluene (ratio 1/1) mixed solvent 10 parts

<Evaluation>
The labels obtained in Examples 1 and 2 and Comparative Examples 1 to 3 were affixed to high-quality paper having a thickness of about 200 μm, and this was mixed with a mixed solvent of methyl ethyl ketone / toluene (mass ratio 1/1), methyl ethyl ketone, ethyl acetate, par After immersing in each solvent of chloroethylene for a few seconds, the solvent was volatilized by exposure to the atmosphere. The surface state of the label before and after immersion in the solvent was visually observed to evaluate fraud detection. The results are shown in Table 1 below.

<Comparison result>
It was confirmed that the surface of the labels of Example 1 and Example 2 changed to a transparent pattern after immersion in the solvent, regardless of the solvent. On the other hand, the label surface of Comparative Example 1 was transparent with no mottled pattern obtained before soaking with any solvent, and the entire surface became cloudy after soaking with the solvent. Similarly, the label surface of Comparative Example 2 remained transparent before and after immersion in the solvent. Furthermore, the label surface of Comparative Example 3 remained a mottled pattern before the immersion in the solvent and remained unchanged after the immersion in the solvent.

  According to the present invention, there is provided a label that can detect peeling due to a solvent and thus prevent tampering and reuse. By attaching this label to a necessary article, it is possible to prevent the counterfeiting or falsification of securities, branded products, certificates, personal authentication media, etc., and to give a function of proving authenticity.

  DESCRIPTION OF SYMBOLS 1 ... Optical change layer, 2 ... Base material, 3 ... 1st area | region, 4 ... 2nd area | region, 5 ... 3rd area | region, 6 ... Printing layer, 7 ... Optical reflection layer, 8 ... Adhesive layer, 9 ... Covering layer 10, 11, 12, label, 13, partially provided optically variable layer

Claims (7)

A fraud detection label having an optically changing layer on one side of the substrate and an adhesive layer on the other side,
The optical change layer is formed from a composition for forming an optical change layer comprising a mixed resin of a first resin and a second resin having a number average molecular weight of 2.5 to 5 times that of the first resin, and a solvent,
The form of the optically variable layer is divided into two regions, a first region and a second region having a visible light transmittance of 5% or more lower than the first region,
The first region is a region where the first resin and the second resin are in a compatible state,
The second region is a region where the first resin and the second resin are in an incompatible state,
And, if the entire region of the optically changing layer is a third region after the optically changing layer is in contact with the solvent that dissolves the first and second resins, the third region is in contact with the solvent before the third region is in contact with the solvent. The fraud detection label characterized by showing visible light transmittance higher than a 2nd area | region. The blending ratio (in terms of mass) of the first resin in the mixed resin is the critical ratio of the first resin when the mixed resin shifts from compatible to incompatible with the unit mass of the solvent as C1 ( %) Is within the range of C1 (%) to C1-10 (%),
Or, a limit ratio of the first resin at the time of transition to the non-phase melt-et compatibilization when the C2 (%), according to claim 1, characterized in that the C2 (%) is in the range of C2 + 10 (%) The fraud detection label described in. The fraud detection label according to claim 1 or 2 , wherein the number average molecular weight of the first resin is in the range of 50,000 to 100,000. The optically changeable layer is characterized in that the third region shows transparency after coming into contact with the solvent from the state where the first region shows transparency and the second region shows transparency. Item 12. The fraud detection label according to any one of Items 1 to 3 . The fraud detection label according to any one of claims 1 to 4 , wherein the first resin is a cellulose derivative. Fraud detection label according to any one of claims 1 to 5, characterized in that the coating layer is laminated on at least a portion of said optical change layer. A labeled article, wherein the fraud detection label according to any one of claims 1 to 6 is pasted through the adhesive layer.

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