JP6175895B2 - Fraud detection label - 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 substrate that has been partially surface-treated to improve adhesiveness, and the hologram layer is partially peeled and destroyed when peeling is attempted. ing.

JP 2009-134528 A Japanese 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 fraud when peeling with a solvent is attempted in a state of being affixed to an article. And

According to a first aspect of the present invention, it comprises a base material, an adhesive layer provided on one surface side of the base material, and an optically variable layer provided on the other surface side of the base material. The optically variable layer is composed of a first resin and a second resin having one number average molecular weight of 5 times or more of the other number average molecular weight, and the first resin and the second resin. before contacting the solvent capable of dissolving at least one, in a first optical state showing a first visible light transmittance, the optically variable layer is in contact Oite, and the solvent after contact with the solvent The blending is changed from the blending of the first resin and the second resin in the previous, so that the first resin and the second resin are incompatible with each other. Change from a state in which the first resin and the second resin are incompatible with each other. By changing the state is a second visible light transmittance of the second optical the area of state and the first resin Blend, as occurs in the optical change layer a second resin shown wherein the door, the second visible light transmittance, the fraud detection label which is a first different visible light transmittance value of 5% or more for visible light transmittance is provided.

  According to the 2nd side surface of this invention, the fraud detection label which concerns on the said 1st side surface is affixed through the said adhesive layer, The labeled article characterized by the above-mentioned is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the label which can detect easily that peeling with the solvent was tried in the state affixed on the article | item, and can prevent reuse and tampering beforehand is provided.

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 organic 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 optical change layer 1 is provided on one surface thereof, and an adhesive layer 6 is provided on the other surface.

  The label substrate 2 is preferably made of a film, and for example, a plastic film such as PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PP (polypropylene) can be used. 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. In this case, the intermediate layer preferably has visible light permeability.

  The adhesive layer 6 is for attaching the label 10 to an article. The adhesive layer 6 can be formed of an adhesive mainly composed of polyester resin, urethane resin, acrylic resin, vinyl chloride resin, or the like. The adhesive layer 6 can be formed by a known method such as a gravure printing method or a screen printing method.

  The optically variable layer 1 contains two kinds of resins having greatly different number average molecular weights at a predetermined ratio. One resin (first resin) constituting the optically variable layer 1 has a first number average molecular weight, the other resin (second resin) has a second number average molecular weight, One of the first and second number average molecular weights is 5 or more times the other number average molecular weight. The optically changeable layer 1 is in the first optical state showing the first visible light transmittance as a whole in a normal state (a state immediately after the production of the label and not in contact with the solvent). However, the optically changeable layer 1 is in contact with a solvent capable of dissolving at least one of the first and second resins, and then is in the second optical state region 3 (FIG. 3) showing the second visible light transmittance. ) In the optically variable layer, wherein the second visible light transmittance is a visible light transmittance that is reduced by 5% or more from the first visible light transmittance. That is, the optically changeable layer 1 contains the first resin and the second resin at such a ratio that when it comes into contact with the solvent, it partially changes from the first optical state to the second optical state. It is a waste. Here, 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 6 so that the label 10 can be peeled from the article in the adhesive layer 6.

  Thus, after the optical change layer 1 in the first optical state of the fraud detection label 10 comes into contact with the solvent capable of dissolving at least one of the first and second resins, the optical change layer 1 In the optically changing layer 1 after contact with the solvent, the region 3 (FIG. 3) in the second optical state is locally generated and the visible light transmittance in both optical states is different by 5% or more. A mottled pattern is easily observed by visual inspection.

  A more effective aspect is a state where the first optical state is transparent to visible light, and the second optical state is opaque to visible light. That is, it is a change from a state in which the first and second resins are compatible to an incompatible (incompatible) state.

  Here, 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 The mixed resin solid substance obtained by drying the mixed resin solution has a light scattering property 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 containing the first and second resins is transparent, or when the film prepared by drying the mixed resin solution is transparent, it can be determined that both resins are compatible.

  In the case of visual observation, 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 why it becomes opaque is that the concentration and composition are not uniform due to the incompatibility of the first and second resins.

  When the optical change layer 1 is formed in a state where the first resin and the second resin are compatible, that is, the optical change layer 1 is formed in a state transparent to visible light. In this case, the optically changing layer 1 comes into contact with the solvent in an attempt to peel the label 10 from the article using the solvent, and the first resin is locally formed in the optically changing layer 1 in the process of volatilization of the solvent. The balance of the blending ratio between the second resin and the second resin is lost, and both resins shift to an incompatible state, become opaque in the local region, and exhibit a mottled pattern as a whole. Since the number average molecular weight of one of the first and second resins is not less than 5 times the number average molecular weight of the other, the dissolution rate of each resin with respect to the solvent is greatly different, and the mottle pattern is easily developed.

  In a preferred embodiment, the ratio of the first resin to the total mass of the first resin and the second resin (the content (% by mass) of the first resin) is based on the mass, and these mixed resins are compatible with each other. The range from the first boundary content C1 (%) to (C1-10) (%) that changes from compatible to incompatible when the content rate from soluble to incompatible content is increased. Preferably, these mixed resins are in the range from the second boundary content C2 (%) to (C2 + 10) (%) where the mixed resin changes from incompatible to compatible.

  As described above, one of the resins of the first and second resins has a number average molecular weight of 5 times or more of the other number average molecular weight, but the number average molecular weight of one of the first and second resins is The number average molecular weight of the other is preferably 40,000 to 800,000.

  For example, specifically, “Dianar BR-88” acrylic resin (number average molecular weight 480,000) manufactured by Mitsubishi Rayon Co., Ltd. can be used as the first resin.

  As the second resin, cellulose derivatives such as “CAB-381-20” cellulose acetate butyrate (CAB) resin (number average molecular weight 70,000) manufactured by EASTMAN 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.

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

  In general, a resin material having a high average molecular weight has a low dissolution rate, and a resin material having a low average molecular weight has a high dissolution rate. For example, in the case of a chain polymer (resin), the longer the molecular chain (the higher the average molecular weight), the greater the attractive force between the polymer molecules, making it difficult to disentangle and disperse the molecular chains 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 average molecular weight (degree of polymerization) and the higher the ratio of crystallinity, the less soluble it is 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.

  As main δ values of the resin material, vinyl acetate (9.1), polymethyl methacrylate (9.2), vinyl chloride (9.3), vinyl acetate (9.4), nitrocellulose (10.1), A methacrylate resin (10.7), cellulose acetate (11), cellulose diacetate (11.4), polystyrene (8.6 to 9.7) and the like are shown 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.

  For example, 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 contrary, in order to decrease the dissolution rate in the solvent A, a solubility parameter different from that of the solvent A is used. What is necessary is just to select resin.

  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 6 so that the label 10 can be peeled from the article in the adhesive layer 6. Usually, such a solvent is an organic solvent, and can dissolve both the first resin and the second resin, 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 contacted with such a solvent and then dried, the optically changing layer 1 on the fraud detection label 10 shown in FIG. 2 changes as shown in FIG. When the label 10 of FIG. 2 before the change is observed from the front side, that is, the observer side, typically, the optical change layer 1 has a visible light transmission property, and the substrate 2 through the optical change layer 1 is transparent. The surface can be visually confirmed. On the other hand, when the changed label 10 of FIG. 3 is observed from the front side, a region 3 having a visible light transmittance reduced by 5% or more is formed, and a mottled pattern is formed, whereby the base material 2 passes through the optical change layer 1. It becomes difficult or impossible to partially observe That is, it can be easily visually confirmed that the label 10 in FIG. 3 has a clear change compared to the label 10 in FIG.

  The optically variable layer can be formed by a known printing method 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.

  A label 11 shown in FIG. 4 includes a printing layer 4 and an optical reflection layer 5 in addition to the optical change layer 1, the substrate 2, and the adhesive layer 6. Typically, the printing layer 4 is provided so as to cover at least a part of the substrate 2, and the optical reflection layer 5 is interposed between the substrate 2 and the adhesive layer 6.

  The print layer 4 is a layer that is provided in an arbitrary color and in the form of a pattern such as a character or a picture, in order to give information to be transmitted.

  The printing layer 4 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 4, 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 4 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 4 to give information by diffracted light or a hologram image.

The optical reflection layer 5 is a layer provided in order to make it possible to easily observe the mottle pattern generated in 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 5 may be provided on the entire surface, or may be partially provided so as to correspond to the shape of characters, designs, 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 5, 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.

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

  In the label 11 shown in FIG. 5, since the optically variable layer 1 and the base material 2 have visible light transparency, when observed from the front side, the stars and the sun as the printed layer 4 are visually observed. In addition, the figure such as the moon and the character of the character string “SECURITY” can be observed, and the portion without the print layer 4 can be observed by the optical reflection layer 5.

  In the fraud detection label 11 shown in FIG. 6, the opaque region 3 is formed in the optical change layer 1 formed as a visible light transmission layer (transparent layer), and forms a mottled pattern. In the region where the opaque region 3 is formed, a graphic such as a star, the sun, and the moon as the printed layer 4 and the character of the character string “SECURITY” are partially or entirely hidden and difficult to observe or Impossible. In the label 11 of FIG. 6, it can be easily confirmed visually that the mottled pattern has a clear change 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. A label 12 shown in FIG. 7 includes a coating layer 7 in addition to the optical change layer 1, the substrate 2, the adhesive layer 6, the printing layer 4, and the optical reflection layer 5. The label 12 of FIG. 7 has a configuration in which a coating layer 7 is further provided on the optically variable layer 1 of the label 11 of FIG.

  The coating layer 7 needs to be made of a material that dissolves or permeates the organic solvent that causes the mottle pattern on the optically variable layer 1. For example, when the organic solvent is a methyl ethyl ketone / toluene mixed solvent, examples of materials that can be selected as the coating layer include acrylic and cellulose acetate butyrate that can be dissolved in the methyl ethyl ketone / toluene mixed solvent or permeate the methyl ethyl ketone / toluene mixed solvent. It is done.

  By using the coating layer, it is possible to enhance physical properties such as surface weather resistance and durability of the label according to the application and purpose while maintaining the function when the organic solvent is used to peel off the label. Is possible.

  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
Here, the label 11 shown in FIGS. 4 and 5 was produced.
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 4.

<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, on the surface of the substrate 2 on which the printed layer is formed, an ink composed of the following composition as an optically changing layer is formed on the entire surface by gravure printing so as to cover the printed layer and have a thickness of 2 μm. did.
<Optical change layer ink>
Acrylic resin (Dianal BR-88 number average molecular weight 480,000) 0.35 parts Cellulose acetate butyrate (average molecular weight 70,000) 0.65 parts Methyl ethyl ketone / 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 5 so as to have a film thickness of 50 nm by a vacuum deposition method. Furthermore, as the adhesive layer 6, an ink made of the following composition was provided on the entire surface so as to have a thickness of 10 μm by a gravure printing method, whereby a label 11 was obtained.
<Adhesive layer ink>
Polyester adhesive 40 parts Ethyl acetate 60 parts.

Example 2
A label 12 shown in FIG. 7 was produced in the same manner as in Example 1 except that the coating layer 7 was provided on the entire surface of the optically variable layer 1. That is, in the label manufacturing method according to Example 1, after the optical change layer 1 is formed, the entire surface of the coating layer 7 is coated with an ink composed of the following composition to a thickness of 0.5 μm by gravure printing. Formed.
<Coating layer ink>
Acrylic resin 10 parts Polyethylene wax 0.5 part Isopropyl alcohol 90 parts.

Comparative Example 1
A label was produced in the same manner as in Example 1 except that the layer was formed using an ink comprising the following composition instead of the optically variable layer 1.
<Ink>
Acrylic resin 2 parts Methyl ethyl ketone / toluene (ratio 1/1) mixed solvent 10 parts.

Comparative Example 2
A label was produced in the same manner as in Example 2 except that an ink comprising the following composition was used as the coating layer.
<Ink>
Polyamideimide resin 1 part Polyethylene wax 0.5 part Ethanol / N-methyl-2-pyrrolidone / toluene (ratio 0.4 / 0.3 / 0.3) mixed solvent 10 parts.

[Evaluation of fraud detection]
In the labels of Example 1, Example 2, Comparative Example 1, and Comparative Example 2, the optically changing layer was in a transparent state. Each label in this state was affixed on an article to be pasted (high quality paper having a thickness of about 200 μm) to obtain a labeled article. These labeled articles were immersed in a mixed solvent having a mass ratio of 1/1 to methyl ethyl ketone / toluene for several seconds, and then exposed to the atmosphere to evaporate the solvent, and the surface state of the label was confirmed.

  The label surfaces of Example 1 and Example 2 had a mottled pattern as shown in FIG. 6, and the pattern and characters of the printed layer were partially hidden, making observation difficult. On the other hand, the entire label surface of Comparative Example 1 became cloudy but did not have a mottled pattern. Further, no change occurred on the label surface of Comparative Example 2.

  In the above examples, a mixed solvent of methyl ethyl ketone and toluene was used as the solvent, but similar results were obtained with other organic solvents (acetone, methyl ethyl ketone, ethyl acetate, perchloroethylene).

  In addition to the resin combinations described above, labels were prepared using the resin combinations shown in Tables 1 to 3 below, and fraud detection was evaluated. In the table, “◯” indicates that the optically changed layer before being immersed in the solvent is compatible in the blending ratio, and “×” indicates that the optically changed layer before being immersed in the solvent. , Indicating that the blending ratio is incompatible. “Mn” indicates a number average molecular weight (unit: g / mol).

In addition, as for the combination of resins in which the result is a “mottled pattern”, as described above, the content value of the first resin in the total mass of the first and second resins increased this value. In the case where it is within the range from the first boundary content value C1 (%) to (C1-10) (%) that changes from compatible to incompatible, or when the previous value is increased If it is within the range from the second boundary content value C2 (%) to (C2 + 10) (%) that changes from incompatible to compatible, it is possible to cause a change from transparent to mottled pattern. . For example, in the case of a combination of cellulose acetate butyrate (CAB) and acrylic (BR-88), if the content value of cellulose acetate butyrate (CAB) in the total mass of these increases this value, it is not compatible. The first boundary content value C1 (%) that changes to incompatible is in the range of 50 to 70%. Therefore, if the first boundary content is within the range of C1 (%) to (C1-10) (%), it is possible to cause a change from transparent to a mottled pattern.

  As described above, according to the present invention, it is possible to detect peeling due to a solvent, and therefore, a label that can prevent tampering and reuse can be provided. 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 ... Label base material, 3 ... Area | region of 2nd optical state, 4 ... Printing layer, 5 ... Optical reflection layer, 6 ... Adhesive layer, 7 ... Covering layer 10, 11, 12 … Fraud detection label

Claims (9)

A substrate;
An adhesive layer provided on one surface side of the substrate;
An optically variable layer provided on the other surface side of the substrate;
The optically variable layer is composed of a first resin and a second resin in which one number average molecular weight is five times or more of the other number average molecular weight, and the first resin and the second resin. Before contacting with a solvent that dissolves at least one, in a first optical state showing a first visible light transmittance,
The optical change layer Oite after contact with the solvent, the formulation from the formulation of the first resin and the second resin before contacting the solvent is changed, whereby the first resin And the second resin is changed from a compatible state to an incompatible state, or the first resin and the second resin are changed from an incompatible state to a compatible state. it allows includes a first resin and said second resin Blend like region of the second optical state showing a second visible light transmittance is generated in the optical change layer,
The second visible light transmittance is a visible light transmittance value different from the first visible light transmittance by 5% or more.
Fraud detection label. In the optically variable layer, the content value of the first resin in the total mass of the first resin and the second resin increases the content value of the first resin on a mass basis. when obtained by the first from the first boundary content value C1 in which the resin and the second resin is changed from a state which is compatible to the state being insoluble (%) (C1-10) (% ) until it is within the scope of, or from the first second boundary content value resin and the second resin is changed to a state which is compatible from the state incompatible C2 (%) (C2 + 10 The fraud detection label according to claim 1, wherein the fraud detection label is within a range up to (%). The number average molecular weight of one of the first resin and the second resin is in the range of 50,000 to 100,000, and the other number average molecular weight is in the range of 40,000 to 800,000. The fraud detection label according to claim 1 or 2.   The first optical state is a state transparent to visible light, and the second optical state is an opaque state to visible light. The fraud detection label according to item 1.   The fraud detection according to any one of claims 1 to 4, wherein the optically variable layer is coated with a coating layer made of a material that dissolves in or permeates the solvent. label.   The fraud detection label according to any one of claims 1 to 5, wherein one of the first and second resins is a cellulose derivative.   The fraud detection label according to any one of claims 1 to 6, wherein an optical reflection layer is further provided between the base material and the adhesive layer. The fraud detection label according to claim 5 , wherein the covering layer is provided so as to cover at least a part of the optically variable layer.   A labeled article, wherein the fraud detection label according to any one of claims 1 to 8 is pasted through the adhesive layer.

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