Fiber pattern transfer method

Abstract

To provide a method for manufacturing an anti-counterfeiting medium that is difficult to copy and counterfeit by using a fiber pattern.SOLUTION: A method for transferring a fiber pattern includes: a substrate selection step of selecting a substrate subjected to embossing or material alteration processing by laser beam in a predetermined wavelength range; a fiber sheet selection step of selecting a fiber sheet that permits transmission of the laser beam in the predetermined wavelength range; and a transfer step of transferring a fiber pattern inherent in the fiber sheet by putting the selected fiber sheet on the selected substrate and by irradiating the laser beam in the predetermined wavelength range to the fiber sheet.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for easily transferring a fiber arrangement or fiber distribution (hereinafter referred to as a "fiber pattern") onto a plastic plate or a metal plate. [Background technology]

[0002] Security printed materials (hereinafter referred to as "security printed materials") that require anti-counterfeiting effects, such as banknotes, passports, securities, identification cards, cards, and passes, are each equipped with various measures (hereinafter referred to as "anti-counterfeiting measures") to prevent counterfeiting, alteration, or tampering.

[0003] As a counterfeit prevention measure, the base of the product is made of a plastic or metal plate. substrate (below" substrate Many methods have been proposed to verify the authenticity of a particular fiber pattern by creating a unique fiber pattern and comparing it with a pre-registered authentic fiber pattern.

[0004] Counterfeit prevention measures using the aforementioned fiber patterns include: substrate At least part of the above discloses a method for determining authenticity by forming a unique information section consisting of a fiber pattern on an identification material made of a light-absorbing substance having a narrow-band light absorption peak, and comparing the absorption peak wavelength in the unique information section with the absorption peak wavelength of a genuine product (see, for example, Patent Document 1).

[0005] Also disclosed is an information identification sheet in which fibrous or flat pieces having absorption in the infrared region are incorporated into a support so as to form a fiber pattern, and the fiber pattern of the pieces in the support is made visible by irradiating the information identification sheet with infrared light having a wavelength of 500 to 1500 nm, which can be read or recorded, and the information of the fiber pattern can be repeatedly identified (for example, Patent Document 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-306058 [Patent Document 2] Japanese Patent Application Publication No. 10-269333 Summary of the Invention [Problem to be solved by the invention]

[0007] However, although the technologies of Patent Documents 1 and 2 have excellent confidentiality because they use special inks and fibers, they are expensive because the fibers are special, and special equipment is required to form the fiber pattern.

[0008] The present invention solves the above-mentioned problems and provides a method for transferring a fiber pattern in a simple manner without using special materials or special equipment. [Means for solving the problem]

[0009] The present invention is a fiber pattern transfer method characterized by comprising a substrate selection step (S1) of selecting a substrate to be textured or have its material altered by laser light in a predetermined wavelength range; a fiber sheet selection step (S2) of selecting a fiber sheet that transmits laser light in the predetermined wavelength range; and a transfer step (S3) of placing the selected fiber sheet on the selected substrate, irradiating the fiber sheet with laser light in the predetermined wavelength range, and transferring the fiber pattern unique to the fiber sheet.

[0010] In the present invention, the fiber sheet has a basis weight of 14.0 g / m 2 The method for transferring a fiber pattern is characterized in that the paper is: [Effects of the Invention]

[0011] The fiber pattern transfer method of the present invention can easily form a fiber pattern on a plastic plate or a metal plate without using special materials or special equipment.

[0012] Furthermore, by using an embossing plate made with the fiber pattern of the present invention, complex fiber patterns can be made efficiently. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is an example showing a fiber pattern transfer method of the present invention. [Figure 2] An example diagram showing an embodiment of the substrate selection step (S1) and the fiber sheet selection step (S2) [Figure 3] An example diagram showing an embodiment of the transfer step (S1) [Figure 4] An example of the fiber pattern after transfer DETAILED DESCRIPTION OF THE INVENTION

[0014] The following description will discuss embodiments of the present invention with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described below, and various other embodiments are also encompassed within the scope of the technical concept set forth in the claims.

[0015] (Fiber pattern transfer method) The fiber pattern transfer method of the present invention, which is explained with reference to Figure 1, is a fiber pattern transfer method characterized by comprising a substrate selection step (S1) of selecting a substrate to be textured or material-altered by laser light in a predetermined wavelength range, a fiber sheet selection step (S2) of selecting a fiber sheet that transmits laser light in the predetermined wavelength range, and a transfer step (S3) of placing the selected fiber sheet on the selected substrate, irradiating the fiber sheet with laser light in the predetermined wavelength range, and transferring the fiber pattern unique to the fiber sheet.

[0016] (Substrate selection process (S1)) The substrate selection step (S1) is a step of selecting a substrate made of metal or resin that can be processed to have irregularities or have its material altered by a laser beam in a predetermined wavelength range.

[0017] (laser light in a specified wavelength range) In the present invention, the laser light in a predetermined wavelength range is a visible light laser in the visible wavelength range of 380 nm to 750 nm or a near-infrared laser (hereinafter referred to as "IR laser") having a wavelength range of 760 nm to 1100 nm. Laser light in the ultraviolet, mid-infrared, or far-infrared wavelength range cannot be used because the fiber sheet described below will be destroyed by heat. As the visible light laser, known visible lasers such as argon lasers and semiconductor lasers can be used as long as the substrate is processed to have irregularities or to alter its material. As long as the substrate is processed to have irregularities or to alter its material, known IR lasers such as fiber lasers, YAG lasers, near-infrared lasers, and semiconductor lasers can be used.

[0018] (substrate) The substrate is not particularly limited as long as it is made of a material that can be textured or altered by laser light in a predetermined wavelength range, and known materials can be used. Examples of metals include known metal materials such as aluminum, copper, and stainless steel, and known thermoplastic resin sheets such as polycarbonate (PC), polyethylene terephthalate glycol (PETG), polyvinyl chloride (PVC), and acrylonitrile-butadiene-styrene copolymer resin (ABS resin). Furthermore, to improve the efficiency of laser light in a predetermined wavelength range, a thermoplastic resin sheet containing a visible light absorbing material or an infrared absorbing material, or a substrate coated with ink containing a visible light absorbing material or an infrared absorbing material, may be used.

[0019] (visible light absorbing material) Next, the visible light absorbing material will be described. As the visible light absorbing material, a material having an absorption wavelength range in the visible light region of 380 nm to 750 nm can be used. For example, cyanine dyes, polymethine dyes, squarylium dyes, porphyrin dyes, phthalocyanine dyes, subphthalocyanine dyes, rhodamine dyes, oxonol dyes, quinone dyes, azo dyes, xanthene dyes, etc. can be used. Among these, known materials such as cyanine dyes and porphyrin dyes can be used. For example, a substrate can be used in which an ink film is formed on a metal or thermoplastic resin sheet by screen printing, gravure printing, intaglio printing, etc., using an ink in which the material is dispersed in a powder or pigment in a varnish, etc.

[0020] Also, known thermoplastic resin sheets such as polycarbonate (PC) containing a visible light absorbing material, polyethylene terephthalate glycol (PETG), polyvinyl chloride (PVC), and acrylonitrile-butadiene-styrene copolymer resin (ABS resin) can be used.

[0021] (Infrared absorbing material) Next, the infrared absorbing material will be described. As the infrared absorbing material, a material having an absorption wavelength range in the near-infrared region of 700 nm to 1100 nm can be used, and examples thereof include a material formed by using a known material such as a glass-based powder containing carbon and diphosphorus pentoxide (PO) as the main component and containing either or both of iron oxide and copper oxide, and applying an ink in which the infrared absorbing material powder or pigment is dispersed in a varnish or the like to a metal or a thermoplastic resin sheet or the like that does not have infrared absorbing properties by screen printing, gravure printing, intaglio printing, or the like.

[0022] Also, known thermoplastic resin sheets such as polycarbonate (PC) containing an infrared absorbing material, polyethylene terephthalate glycol (PETG), polyvinyl chloride (PVC), and acrylonitrile-butadiene-styrene copolymer resin (ABS resin) can be used.

[0023] (Fiber sheet selection process (S2)) The fiber sheet selection step (S2) is a step (S2) of selecting a fiber sheet that transmits laser light in the same predetermined wavelength range as the laser light in the predetermined wavelength range of the substrate selected in the substrate selection step (S1). The reason for selecting a fiber sheet that transmits laser light in the same wavelength range is to focus the laser light in the predetermined wavelength range as it passes through the fiber, and transfer the fiber pattern to the selected substrate.

[0024] (fiber sheet) The fiber sheet may be any fiber sheet that transmits laser light in a predetermined wavelength range. Examples of such fiber sheets include leaves of plants such as corn, abaca, wheat, barley, rice, hemp, sorghum, sugarcane, pineapple, kenaf, sisal, jute, banana, and tea leaves, as well as paper, nonwoven fabric, and other known fiber sheets with fiber patterns made from plant fibers, wood fibers, or resin fibers. It is preferable that the paper, nonwoven fabric, and other materials that absorb or reflect laser light in a predetermined wavelength range, such as clay, kaolin, or titanium oxide, be coated, or that no additives be used. Treated paper, such as coated paper, is not suitable. The basis weight of the fiber sheet is 14.0 g / m. 2 If the thickness exceeds this range, it will be difficult to transmit laser light in a predetermined wavelength range, making it difficult to transfer the fiber pattern.

[0025] (Transfer process (S3)) The transfer step (S3) is a step in which a selected fiber sheet is placed on a selected substrate, and the fiber sheet is irradiated with laser light in a predetermined wavelength range to transfer the fiber pattern specific to the fiber sheet as laser marks. Note that laser marks refer to changes in the material of the substrate caused by the laser light (carbonization, discoloration) or irregularities consisting of minute depressions.

[0026] (Placed) When placing the fiber sheet on the substrate, it is preferable that there be no gaps between the substrate and the fiber sheet. If there are gaps, it will be difficult to accurately transfer the fiber pattern of the fiber sheet to the substrate. Therefore, it is recommended to use an adhesive, pressure-sensitive adhesive, etc. to adhere the substrate and the fiber sheet to a range in which the laser light in the specified wavelength range is not affected by absorption or reflection, etc.

[0027] (irradiation) The laser beam is irradiated onto the entire surface or a portion of the fiber sheet placed on the substrate with laser beams in the aforementioned predetermined wavelength range. The average power P (unit: W) of the laser beam is not particularly limited as long as it does not affect the fiber sheet, but is, for example, 0.5 to 30 W, preferably 1 to 20 W. When the laser beam is a pulsed laser, its repetition frequency is not particularly limited, but is 1 to 400 kHz, more preferably 50 to 100 kHz.

[0028] The irradiation speed of the laser light may be adjusted as appropriate depending on the type of fiber sheet and substrate, productivity, and the depth of the recesses of the fiber pattern to be transferred to the substrate (laser marks). For example, the moving speed of the laser light spot is 0.5 to 10 m / s, preferably 1 to 6 m / s. Setting the speed within this range is preferable because industrial productivity (drawing speed) can be achieved.

[0029] The fibers that make up the fiber sheet have the property of transmitting laser light. Therefore, when laser light is irradiated onto the fiber sheet, the laser light is focused as it passes through the fibers that make up the fiber sheet, and the fiber pattern, which is the shape and distribution of the fiber sheet, is transferred to the surface of the substrate as laser marks.

[0030] In the case of paper, the plant fibers (cellulose) that make up the raw material for fiber sheets are intertwined in an irregular manner without any controlled positional relationships, resulting in a random mesh structure that is stacked in layers across the thickness to form "paper." The randomly intertwined structure created by the plant fibers makes it impossible to intentionally create an identical copy. This pattern can therefore serve as unique information for each piece of paper (similar to a human fingerprint, also known as a paper pattern), improving counterfeit prevention measures.

[0031] For example, a metal plate is processed to have a concave and convex shape to form an embossing plate with a fiber pattern in the concave portion, and the embossing plate is used to print a plastic substrate A fiber pattern may be formed on the plastic. substrate By reproducing the appearance and texture of paper, which is a fiber pattern, onto the surface of a card, it is possible to inexpensively create multiple copies of the same fiber pattern. The embossing plate used for this process transfers the shape and distribution of the actual paper fibers, making it difficult to counterfeit the same pattern. substrate On the other hand, the fiber pattern may be transferred according to the present invention and combined with personal information to form a forgery prevention medium.

[0032] In addition, to determine whether the fiber pattern after transfer is genuine or not, an image of the fiber pattern of the genuine product, density data due to fiber entanglement, position data of feature points due to fiber entanglement, etc. can be used. By recording the feature amounts of the genuine product in advance, known determination techniques can be used, such as matching with image data or comparing the feature amounts to determine whether they are within a standard value. [Example]

[0033] The present invention will be described below with reference to the accompanying drawings, but the present invention is not limited to these examples.

[0034] As shown in Figure 2(a), in the substrate selection step (S1), a stainless steel plate (1) with a smoothly polished surface was selected as the substrate, and an embossing plate (A1) onto which a fiber pattern was transferred was prepared. Also, as shown in Figure 2(b), in the fiber sheet selection step (S2), a fiber sheet with a basis weight of 7.3 g / m2 was selected. 2 The paper (2) (ash-burned paper) was selected. The fiber pattern (3) of paper (2) had the fiber shape and distribution shown in the enlarged diagram indicated by the dotted line.

[0035] As shown in Figure 3(a), in the transfer process (S3), paper (2) was attached to the surface of stainless steel plate (1) using a water-based adhesive diluted with tap water, and then left to dry naturally. Next, as shown in Figure 3(b), a Keyence YVO4 laser marker was used to emit laser light (4) in the near-infrared wavelength range (1064 nm wavelength), and the laser light (4) was irradiated (5) onto a portion of the paper (2) from the paper (2) side of the stainless steel plate (1) to which the paper (2) was attached. The processing conditions for the laser light (4) were: laser power 50%, scan speed 600 mm / s, Q-switch frequency 60 kHz, scan pitch 0.042 mm, and 10 irradiations.

[0036] Next, as shown in Figure 4, after irradiation with the laser beam (4), the paper (2) was peeled off from the surface of the stainless steel plate (1), and the processed state of the area (5) irradiated with the laser beam was confirmed. As shown in the enlarged partial view indicated by the dotted line, the surface of the stainless steel plate (1) in the area irradiated with the laser beam (5) had a fiber pattern (3), which represents the fiber shape and distribution of the paper (2), transferred onto it. Furthermore, the fiber pattern (3) on the stainless steel plate (1) irradiated with the laser beam (4) left linear processing marks with a concave cross section in the areas where the fibers were present, confirming that it had been successfully processed into an embossed plate (A1).

[0037] Next, using the prepared embossing plate (A1), it was confirmed whether the same fiber pattern (3) could be transferred to a resin plate. A polycarbonate sheet was used as the resin plate, and the embossing plate (A1) was thermocompressed onto the surface of the polycarbonate sheet (185°C, 2.5 MPa, 30 seconds). After thermocompression bonding, the image data of the fiber pattern (3) on the embossing plate (A1) was compared with the image data of the fiber pattern (3) transferred to the surface of the polycarbonate sheet by pattern matching. They were identical, confirming that the fiber pattern (3) on the surface of the polycarbonate sheet had been successfully transferred. [Explanation of symbols]

[0038] A1 embossed version 1 stainless steel plate 2. Paper 3 Fiber Pattern 4. Laser light 5. Area irradiated with laser light

Claims

1. a substrate selection step of selecting a substrate to be subjected to roughening or material modification processing using laser light in a predetermined wavelength range; a fiber sheet selection step of selecting a fiber sheet that transmits laser light in the predetermined wavelength range; A fiber pattern transfer method comprising a transfer step of placing the selected fiber sheet on the selected substrate, irradiating the fiber sheet with laser light in the specified wavelength range, and transferring the unique fiber pattern of the fiber sheet to the substrate.

2. The fiber sheet has a basis weight of 14.0 g / m ２ 2. The method for transferring a fiber pattern according to claim 1, wherein the paper is:

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