JP5601145B2 - Security thread, manufacturing method thereof, and security paper - Google Patents

Description

  The present invention relates to an anti-counterfeit security paper used in banknotes, securities and the like, and a method for manufacturing the same.

  2. Description of the Related Art Conventionally, banknotes and securities are used as security for preventing forgery by threading paper. For example, if a hologram is used for the thread, it is adopted as a forgery prevention technique by taking advantage of the fact that it is difficult to reproduce by color copy or image capture by a scanner. This is mainly used for visual authenticity determination. Normally, when the security is provided, a window is opened to prevent the paper layer from overlapping the front surface of the security when the thread is inserted in order to improve visibility.

  On the other hand, as a method for performing verification with a reader provided in ATM or the like, there is a method of providing a magnetic layer on a thread. For example, Patent Document 1 proposes a method of providing a magnetic bar code on a thread. Patent Documents 2 and 3 propose a method of performing authenticity determination by reading magnetic information using a plurality of layers of magnetic material or a plurality of threads.

  Further, in Patent Document 4, as a method for improving security, a black layer such as a magnetic layer is provided in a pattern on aluminum vapor deposition, and a security functional layer such as liquid crystal is provided on the aluminum vapor deposition etched away. Proposed. According to this, a black part and a transparent part are partly obtained, and a thread having an optical effect peculiar to liquid crystal is obtained on the entire upper surface.

Japanese Patent Laid-Open No. 11-245569 JP 2002-266290 A JP-A-2005-232617 US Pat. No. 7,179,393

However, in the above-described technique, since an optical effect with a black background is observed, the overall optical effect is dark. In addition, when the thread is rolled into the paper, the security function layer is positioned on the surface side of the base material. Therefore, the banknote that is premised on long-term use becomes an uneasy factor in terms of durability. Furthermore, even if the liquid crystal layer is applied on the black layer, the liquid crystal layer is not oriented and the optical effect is not obtained. Therefore, after the liquid crystal is applied on another orientation film and oriented, the black layer is interposed via the adhesive layer. There is a problem that a procedure such as pasting is necessary, which is complicated and increases the manufacturing cost.
The present invention has been made paying attention to the above points, and an object thereof is to provide a security thread having a simple structure and a bright gloss.

In order to solve the above-mentioned problems, the invention described in claim 1 of the present invention is such that a metallic gloss thin film layer is partially formed on one surface of a transparent substrate, and the metal gloss thin film layer is formed on the metal gloss thin film layer. A black or dark magnetic layer having the same shape as the surface of the glossy thin film layer is laminated in contact with the interface, an ultraviolet fluorescent light emitting layer is laminated on the magnetic layer, and ultraviolet light is partially applied to the ultraviolet fluorescent light emitting layer. A security thread characterized by laminating an absorption layer is provided.
Next, the invention described in claim 2 is characterized in that the magnetic layer uses a vinyl chloride-vinyl acetate-maleic acid copolymer resin as a binder with respect to the structure described in claim 1. .

In the following, the invention described in claim 3, to the structure according to claim 1 or claim 2, wherein the transparent substrate, characterized in that it is a multi-layer thin film formed by laminating thin films.
Next, in the invention described in claim 4 , an optical layer made of liquid crystal is applied to the other surface of the transparent substrate with respect to the configuration described in any one of claims 1 to 3 , It is characterized by being oriented.
Next, the invention described in claim 5 is the structure described in any one of claims 1 to 4, wherein each of the magnetic layer, the ultraviolet fluorescent light emitting layer, and the ultraviolet absorbing layer is chlorinated. A vinyl-vinyl acetate-maleic acid copolymer resin is used as a binder.

Next, according to the sixth aspect of the present invention, a metallic glossy thin film layer is provided on the entire surface of a transparent substrate, and then a black or dark magnetic layer is provided on the entire surface to form an alkaline or acidic etching solution. A method for manufacturing a security thread is provided, wherein the metallic luster thin film layer is partly removed by immersion in the substrate and an ultraviolet fluorescent light emitting layer is provided on the entire surface.
Next, the invention described in claim 7 is obtained by rolling the security thread according to any one of claims 1 to 5 into a sheet with the other surface of the transparent substrate as a surface. The security paper characterized by the above is provided.

  According to the security thread of the present invention, when viewed from the other surface side of the transparent substrate, the black of the magnetic layer is concealed by the metallic glossy thin film layer, and the security thread has a bright gloss feeling. In addition, when fluorescent light is emitted with black light, fluorescent light emission can be observed in a portion where the metallic glossy thin film layer does not exist.

It is a structure explanatory view of a security thread according to an embodiment based on the present invention. It is another structure explanatory drawing of the security thread based on embodiment based on this invention. It is another structure explanatory drawing of the security thread based on embodiment based on this invention. It is a typical sectional view of security paper. It is explanatory drawing of a security paper.

Embodiments of the present invention will be described below with reference to the drawings.
(Security thread)
As shown in FIG. 1, the security thread 1 of the present embodiment has a metallic luster thin film layer 3, a magnetic layer 4, and an ultraviolet fluorescent light emitting layer 5 in this order on one surface (lower surface in FIG. 1) of the transparent substrate 2. It is configured by stacking.
The transparent substrate 2 serves as a support for the metallic luster thin film layer 3 and the magnetic layer 4, and a known plastic material or paper material can be used, but generally availability, cost, In view of strength, it is preferable to use a polyethylene terephthalate (hereinafter abbreviated as PET) film having a thickness of about 3 to 50 μm. However, the transparent substrate 2 is not limited to this. If necessary, an optical effect layer such as a hologram may be provided between the transparent substrate 2 and the metallic luster thin film layer 3. Of course, in order to provide adhesion between these layers, a known anchor agent or corona treatment may be provided.

Further, as the transparent substrate 2, a multilayer optical film in which very thin films are laminated can be used. The multilayer optical film can be used in the same manner because various colors are observed when the angle is changed by interference between light reflected at the boundary between different layers and is basically colored and transparent.
The metallic luster thin film layer 3 is a layer that can be removed by etching. For example, a vapor deposition film of a thin film of aluminum or tin can be used. After the etching, the part without the magnetic layer 4 described below is removed, so-called demetallization. That is, the metallic luster thin film layer 3 is partially formed on one surface of the transparent substrate 2.

  The magnetic layer 4 is a layer formed by using conventionally known magnetic powder and a binder resin as main components and acting as a mask layer in the etching of the metallic glossy thin film layer 3. Further, as a material of the magnetic layer 4, a colorant such as carbon black may be added as necessary. Examples of magnetic powder include hard magnetic materials such as iron, γ-iron oxide, magnetite, Co-coated γ-iron oxide, barium ferrite, strontium ferrite, and alnico, as well as nickel, permalloy, sendust, and carbonyl iron. A soft magnetic material can also be used, and the material is not limited to this. In the case of a hard magnetic material, magnetic recording can be performed on itself. In the case of a soft magnetic material, the presence or absence can be detected by applying a magnetic bias. The binder resin must be a resin that is suitable for etching, has good metal adhesion, and does not deteriorate its adhesion even when magnetic powder is added. As a binder resin that satisfies this requirement, there is a vinyl chloride-vinyl acetate-maleic acid copolymer resin. In addition to this resin system, it was confirmed that the function as a mask layer was remarkably lowered by adding a magnetic powder to reduce the mask effect or reduce the adhesion. The ratio between the magnetic powder and the binder is determined by the balance with the layer thickness, but can be set in the range of 0.5 / 1 to 4/1, preferably 1/1 to 2/1. Further, the layer thickness can be set from 0.5 μm to 20 μm, preferably from 1 μm to 5 μm, and any layer thickness may be used as long as a magnetic output that can be read by the magnetic reader is obtained. Moreover, you may use as a two-component curable ink using an isocyanate type hardening | curing agent as needed.

The ultraviolet fluorescent light-emitting layer 5 is formed by applying an ink in which a conventionally known phosphor that emits visible light when excited by ultraviolet light is dispersed in a binder. Examples of the phosphor include green phosphors, yellow phosphors, red phosphors, and blue phosphors that emit green, yellow, red, and blue visible light. As the binder, a conventionally known resin material can be used, but a resin having good adhesion between both the magnetic layer 4 and the substrate 2 in contact is preferable. For example, in addition to vinyl chloride-based resins such as vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic acid copolymer resin, vinyl chloride-vinyl acetate-vinyl alcohol copolymer resin, polyester resin, urethane Resins such as resin can be used.
When the security thread 1 having the above-described configuration is viewed from the other surface (upper surface in FIG. 1) of the transparent base material 2, the black of the magnetic layer 4 is hidden by the metallic thin film layer 3 and has a bright gloss feeling. It becomes a security thread. In addition, when the fluorescent light is emitted with black light, the fluorescent light emission can be observed in a portion where the metallic luster thin film layer 3 does not exist.

(Another security thread)
Next, another security thread according to the present embodiment will be described with reference to FIG.
As shown in FIG. 2, the security thread 1 has an ultraviolet absorption layer 6 partially formed on the ultraviolet fluorescent light-emitting layer 5 in the structure shown in FIG. Other structures are the same as those of the security thread shown in FIG.
When the ultraviolet absorption layer 6 is not provided, the entire back surface (lower surface side) emits fluorescence. On the other hand, in the case where the ultraviolet absorbing layer 6 is present, only the portion where the ultraviolet absorbing layer 6 is present does not emit fluorescence, and pattern-like light emission occurs. The ultraviolet absorbing layer 6 is obtained by adding an ultraviolet absorber to a binder. As the ultraviolet absorber, for example, a benzotriazole-based absorbent or a benzophenone-based absorbent can be used.

(Another security thread)
Next, another security thread according to the present embodiment will be described with reference to FIG.
As shown in FIG. 3, the security thread 1 is obtained by forming an optical layer 7 made of liquid crystal on the surface side (upper surface side) of the transparent substrate 2 with respect to the structure shown in FIG. 1. Other structures are the same as those of the security thread shown in FIG. Moreover, you may provide the ultraviolet absorption layer 6 like FIG.
The optical layer 7 of the present embodiment is a cholesteric liquid crystal layer. Usually, since a PET film is stretched and molecularly oriented, it can be naturally oriented by applying a cholesteric liquid crystal thereon to obtain a unique optical effect.

(Security thread manufacturing method)
Next, a method for manufacturing a security thread according to this embodiment will be described.
An optical effect layer such as a hologram is provided on the transparent substrate 2 as necessary, and the metallic gloss thin film layer 3 is provided thereon by a vapor phase coating method such as vapor deposition or sputtering.
Next, the magnetic layer 4 is printed on the metallic glossy thin film layer 3 with a desired pattern, and then the metallic glossy thin film layer 3 exposed by etching is removed. By doing in this way, the shape of the metallic luster thin film layer 3 and the magnetic layer 4 can be matched completely, and the black or dark magnetic layer 4 can be concealed when viewed from the transparent substrate 2 side.
Next, if necessary, an ultraviolet fluorescent light emitting layer 5 and an ultraviolet absorbing layer 6 are provided, and a cholesteric liquid crystal layer 7 is provided on the back surface side (upper surface side) of the transparent substrate 2.
Thus, the security thread 1 can be obtained.

(Security paper)
Next, the security paper 11 of this embodiment in which the security thread 1 is inserted will be described.
As shown in FIG. 4, the security paper 11 is composed of the thread 1 sandwiched between a paper 12 on the back surface having no window opening and a paper 13 on the front surface having a window opening.

In order to provide the security paper having the configuration shown in FIG. 4, the paper 12 is first made to have an appropriate thickness, and then the paper 13 having a window is made. And according to the position of the window of the paper 13, the thread | sled 1 can be piled up on the paper 12, and the paper 13 previously made can be piled up, and it can obtain by the method of fully taking out moisture and drying.
When the security thread 1 is rolled in, the surface (the lower surface in FIG. 1) provided with the magnetic layer 4 of the transparent base 2 is directed to the back side of the paper 12 that does not have a window opening. FIG. 5 is a plan view seen from the paper 13 side.

A 25 μm-thick PET film (Lumirror 25T60, manufactured by Toray Industries, Inc.) was used as the transparent substrate 2, and aluminum was provided thereon with a thickness of 50 nm to form a metallic glossy thin film layer 3. Next, a magnetic ink composed of the following “composition of magnetic layer ink” was provided in a thickness of 2 μm by the gravure printing method to form a magnetic layer 4.

"Composition of magnetic layer ink"
・ Magnetite magnetic powder MG-7000 (Mitsui Metal Mining Co., Ltd.) 15 parts by weight ・ Vinyl chloride-vinyl acetate-maleic acid copolymer resin Solvein M5
(Nissin Chemical Industry Co., Ltd.) 5 parts by weight ・ Methyl ethyl ketone 40 parts by weight ・ Toluene 40 parts by weight

  The coated product on the magnetic layer 4 prepared above is taken out by dipping in a 2% sodium hydroxide solution at 55 ° C. for 10 seconds, neutralized with dilute hydrochloric acid, washed with tap water, and demetallized into the shape of the magnetic layer 4 An intermediate product was obtained. In this state, when viewed from the PET film surface side, the metallic luster of the shape of the magnetic layer 4 was observed, and from the magnetic layer surface side, the black color of the magnetic layer was observed. In both cases, the pattern of the magnetic layer 4 was observed as it was.

Next, an ultraviolet fluorescent light-emitting layer ink having the following composition of “ultraviolet fluorescent light-emitting layer ink” was provided on the same surface in a thickness of 2 μm by a gravure printing method, thereby forming an ultraviolet fluorescent light-emitting layer 5.

“Composition of UV fluorescent layer ink”
・ Green phosphor 3 parts by weight ・ Vinyl chloride-vinyl acetate-maleic acid copolymer resin Solvein M5
(Nissin Chemical Industry Co., Ltd.) 17 parts by weight ・ Methyl ethyl ketone 40 parts by weight ・ Toluene 40 parts by weight

  The security thread 1 was cut out by slitting to 5 mm width from the thread raw material thus obtained. Using this thread 1, the size of the window opening was 8 mm wide and 10 mm high, and paper was made by hand so that three windows were provided at 10 mm intervals, and sufficiently dehydrated and dried to obtain security paper 21. . The final size of the security paper 11 was 16 cm × 8 cm. This is shown in FIG. When black light was irradiated from the PET film side, green fluorescence was observed from the hole in the metallic thin film layer 3.

In Example 1, an ultraviolet fluorescent light emitting layer was provided, and an ultraviolet absorbing layer ink composed of “the composition of the ultraviolet absorbing layer ink” was patterned in a thickness of 5 μm by screen printing (plate: 150 lines, sol thickness 20 μm). The ultraviolet absorption layer 6 was obtained.
"Composition of UV absorbing layer ink"
・ Ultraviolet absorber Tinuvin P (manufactured by BASF) 3 parts by weight ・ Vinyl chloride-vinyl acetate-maleic acid copolymer resin Solvein M5
(Nissin Chemical Industry Co., Ltd.) 27 parts by weight ・ Cyclohexanone 70 parts by weight

The following was scraped into paper in the same manner as in Example 1 to obtain a security thread. When black light was irradiated from the open side of the window, green fluorescent light emission was observed from the vacant hole of the metallic luster thin film layer 3. Further, when the black light was irradiated from the surface without the open window on the back surface, the fluorescence emission was weak only at the portion where the ultraviolet absorption layer 6 was printed, and the fluorescence emission was obtained in a pattern.

  It was produced in the same manner as in Example 1 except that the transparent substrate 2 in Example 1 was changed to a multilayer film (manufactured by Toyobo Co., Ltd.).

A cholesteric liquid crystal layer composed of “the composition of the cholesteric liquid crystal layer” was provided on the back side of the transparent substrate 2 of Example 1 with a thickness of 2 μm using a wire bar coater.

"Composition of cholesteric liquid crystal layer"
・ Nematic liquid crystal Paliocolor LC242 (manufactured by BASF) 50 parts by weight ・ Chiral agent Paliocolor LC756 (manufactured by BASF) 5 parts by weight ・ UV polymerization initiator Irgacure 369 (manufactured by BASF) 3 parts by weight ・ Methyl ethyl ketone 42 parts by weight

A unique optical effect was obtained in which the cholesteric liquid crystal was aligned along the orientation of the PET film and the color changed when tilted. Further, when black light was irradiated from the cholesteric liquid crystal layer side, green fluorescent light emission could be observed from the hole portion of the metallic glossy thin film layer 3 under the optical effect of the cholesteric liquid crystal layer 7.

DESCRIPTION OF SYMBOLS 1 Security thread 2 Transparent base material 2 Base material 2 Transparent base material 2 Example 3 Metal gloss thin film layer 4 Magnetic layer 4 Magnetic layer 5 Ultraviolet fluorescent light emitting layer 6 Ultraviolet absorption layer 7 Optical layer (cholesteric liquid crystal layer)
11 security paper 12 paper 13 paper

Claims (7)

A metallic luster thin film layer is partially formed on one surface of the transparent substrate, and a black or dark magnetic layer having the same shape as the surface shape of the metallic luster thin film layer is in contact with the metallic luster thin film layer on the interface. A security thread characterized in that an ultraviolet fluorescent light emitting layer is laminated on the magnetic layer , and an ultraviolet absorbing layer is partially laminated on the ultraviolet fluorescent light emitting layer.   The security thread according to claim 1, wherein the magnetic layer uses vinyl chloride-vinyl acetate-maleic acid copolymer resin as a binder. The security thread according to claim 1 or 2, wherein the transparent substrate is a multilayer thin film formed by laminating thin films . The security thread according to any one of claims 1 to 3, wherein an optical layer made of liquid crystal is applied and oriented on the other surface of the transparent substrate. 5. Each of the magnetic layer, the ultraviolet fluorescent light emitting layer, and the ultraviolet absorbing layer uses vinyl chloride-vinyl acetate-maleic acid copolymer resin as a binder. The security thread according to claim 1.   A metallic gloss thin film layer is provided on the entire surface of a transparent substrate, and then a black or dark magnetic layer is partially provided on the transparent substrate. The metallic gloss thin film layer is partially removed by immersion in an alkaline or acidic etching solution. And a method of manufacturing a security thread, further comprising providing an ultraviolet fluorescent light emitting layer on the entire surface.   A security paper, wherein the security thread according to any one of claims 1 to 5 is rolled into a paper with the other surface of the transparent substrate as a front surface.

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