JP2011257679A - Optical sheet and anti-counterfeit paper - Google Patents

Abstract

[PROBLEMS] To provide an "arbitrary color" at an "arbitrary position" in a hologram manufacturing process, and a pattern in which an embossed layer is colored, a pattern of an embossed layer pattern, and a reflection that remains without being removed by a demetalization process To provide an anti-counterfeit optical sheet in which the registration of the three layer patterns completely coincides and an anti-counterfeit paper using the anti-counterfeit optical sheet.
An optical sheet having a metal reflective layer on an embossed layer forming an optical element, and further provided thereon a plurality of colored layers having different colors. The anti-counterfeit optical sheet is transferred to a sheet of paper.
[Selection] Figure 1

Description

  The present invention is a thread (also referred to as a strip, a filament, a thread, a safety band, etc.) suitable for a field where anti-counterfeiting that is an optical sheet is desired, a transfer foil, a manufacturing method thereof, and an optical sheet thereof Anti-counterfeit paper made of threaded paper with thread or transfer foil transferred or engraved, anti-counterfeit printed matter such as securities, banknotes, etc., and method for determining authenticity of anti-counterfeit paper or anti-counterfeit printed matter About.

  The thread is also effective for aesthetic design outside the field of anti-counterfeiting measures, and is also suitable for providing a product with excellent decorativeness in the field of clothing and the like. In particular, the thread according to the present invention has a metal thin film layer patterned according to a desired character or pattern, which is one of the important elements leading to a suitable effect in the above-mentioned field. A typical patterning method for the metal thin film layer is a so-called demetalizing process.

  For securities such as banknotes and gift certificates, and for public documents and identification cards such as passports and driver's licenses, a medium having a fine structure, often called a hologram, is given for the purpose of preventing forgery. In recent years, counterfeit goods of securities including banknotes have been given examples of counterfeit holograms that imitate the appearance, and the anti-counterfeit effect of silver holograms with aluminum deposition generally called embossed type is It tends to decline.

  As one means for obtaining a higher anti-counterfeit effect, a technique for imparting a color other than silver to a hologram has already been implemented. One is a technology that colors the embossed layer that forms the diffractive structure of the hologram with a dye, and uses evaporated aluminum as a reflective layer to give a metallic luster such as gold instead of silver, such as Nigerian Naira banknotes. In addition to national banknotes, it is also used in holograms for gold cards for credit cards.

  However, with this existing technology, when a demetalization process is performed to remove a part of the reflective layer by etching, the embossed layer where the reflective layer has been removed will also be colored, resulting in both design and anti-counterfeiting effects. It will be lacking. In fact, none of the golden holograms and gold credit cards used in some African and European countries has been demetallized (Patent Document 1).

  The other is a technology that processes the embossed layer as usual and replaces the deposited metal with a metal such as copper or tin that has a metallic luster other than silver, which is demetalized in the form of a striped hologram on a Hungarian forint banknote. Copper was used as a deposition layer for a period of time. Unlike the technique of coloring the embossed layer, this has the advantage that the metal layer can be etched and demetalized as in the case of aluminum deposition as described above. However, the durability of copper against corrosion and the like has become a problem with respect to aluminum, so the banknotes in the country have now been changed to stripe holograms that have been subjected to demetallization processing of aluminum deposition. In addition, this technology has a limitation that it is not possible to select a color other than the specific luster of metal.

As described above, there are the problems of "Able to give color but no position selectivity" and "A point selectivity by etching but only a single color can be given and is inferior to conventional products" Embossed holograms are silver-colored with a metallic luster of aluminum and those that have been subjected to demetalization, those that have a metallic luster other than silver due to a colored embossed layer, but that have not been demetalized, Other than aluminum, it can be broadly classified into those having a single-color metallic luster other than silver and having been demetallized. However, although it can be colored, it is limited to a single color.

  An anti-counterfeit paper called “threaded paper” in which a thread is formed in a paper layer is well known. Since the threaded paper requires a very advanced technique for manufacturing, it has a great effect in preventing forgery, and as is well known, it is often used for banknotes in various countries.

  There are two types of threaded paper, one of which is threaded into the paper and not exposed to the paper surface, and the other is a part of the thread on the paper surface. It is called “paper with open window thread” exposed intermittently.

  The former is a method for producing paper that is not exposed on the surface. The nozzle is inserted into the flow of the stock in the slice part of the long paper machine, and the thread is fed while water is passed through the nozzle to form the paper formed on the paper network. A method is known in which threads are drawn in a rat (Patent Document 2).

  Further, a method is known in which a thread insertion device is installed in the stock flowing out of the flow box of the long paper machine, and the thread is made while the thread and the stock are not in contact with each other by airflow (Patent Document 3). ).

  Or, using a circular paper machine with two or more layers, using two or more layers of paper, a thread with an uneven inner wall is used to feed the threads between the paper layers, and the threads are made between the paper layers. And the like have been proposed (Patent Document 4).

JP 2003-226085 A Japanese Patent Laid-Open No. 51-130309 JP-A-2-169790 Japanese Patent Publication No. 5-40080

  The present invention solves such problems of the prior art, and the problem is that the “arbitrary position” is given to the “arbitrary position” in the hologram manufacturing process, and the embossed layer is colored. Pattern, embossed layer pattern pattern, and anti-counterfeit optical sheet using the anti-counterfeit optical sheet, in which the registration of the three patterns of the reflective layer pattern that has not been removed by the demetalization process completely coincides To provide paper.

As a means for solving the above-mentioned problems, the invention according to claim 1 is characterized in that a metal reflective layer is provided on an emboss layer forming an optical element, and a plurality of colored layers having different colors are provided thereon. An optical sheet characterized by the above.

  The invention according to claim 2 is the optical sheet according to claim 1, wherein the light transmittance of the colored layer is in the range of 70 to 90%.

  The invention according to claim 3 is the optical sheet according to claim 1 or 2, wherein the metal reflective layer is formed only in the colored layer region.

  According to a fourth aspect of the present invention, there is provided the optical according to any one of the first to third aspects, wherein a protective layer is provided on the metal reflective layer, the embossed layer, and the colored layer. It is a sheet.

  According to a fifth aspect of the present invention, there is provided an anti-counterfeit paper characterized in that the optical sheet according to any one of the first to fourth aspects is transferred onto a paper sheet.

  According to the present invention, it becomes possible to give an embossed hologram a metallic luster other than silver in an arbitrary place with an arbitrary number of colors, and it is also possible to demetalize an arbitrary place. It is possible to manufacture a hologram that is colored only in the reflective layer and has been subjected to demetalization while maintaining high durability.

  In addition, since holograms with a metallic luster other than silver, which were often made in a single color, can be manufactured in two or more colors, it is possible to determine the authenticity by visual inspection than holograms with metallic luster only in silver. However, it becomes easier for the general public, and the ease of authenticity determination is dramatically improved.

  By making it possible to produce finely colored patterns, such as gold demetalized holograms, it can be used as an improved version of the non-golden demetalized holograms that have been used in the banknote industry. It becomes. In addition, by realizing multicolor expression, it is possible to impart design characteristics that are superior in terms of design to the hologram. By arbitrarily adjusting the color of the ink to be colored, it is possible to improve both the freedom in the design and the difficulty of reproduction (forgery prevention effect).

It is a conceptual diagram explaining an example of embodiment which shows the manufacturing process of the multicolor hologram transfer foil of this invention. It is a conceptual diagram explaining an example of embodiment of the forgery prevention paper using the multicolor hologram thread of this invention. It is a conceptual diagram explaining an example of embodiment of the forgery prevention paper using the stripe type | mold and patch type "spot" transfer foil which consist of a multicolor hologram of this invention.

  The multicolor hologram stripe type transfer foil 15 is manufactured by a process as shown in FIG. A shows a state in which a release layer 11 is provided on the substrate 1, and a surface relief hologram is thermally transferred to the embossed layer 2 coated thereon, and a reflective layer 5 is formed on the surface of the embossed pattern portion 3. The colored layer 6 can be laminated on the embossed pattern portion 3 by a printing method in a plurality of times, and a plurality of colors can be laminated so that the hologram layer has three or more colors. The colored layer 6 is used as a resist, and the reflective layer 5 in the non-embossed pattern portion is removed.

  B shows a state in which the peeling adhesive layer 13 and the substrate 1 are laminated, and C shows a state in which the peeling layer 11 and the substrate 1 are peeled from the embossed layer. D was irradiated with ultraviolet rays from the substrate 1 to photocur the release adhesive layer 13 to obtain a photocured release adhesive layer 18, and then the substrate 1 was peeled off to produce a multicolor hologram stripe transfer foil 15. .

  FIG. 2 shows a plane in an example of an embodiment of the anti-counterfeit paper 19 using the multicolor hologram thread 14 and a cross section of the multicolor hologram security thread portion 14, and the thread is engraved on the paper. Are intermittently exposed from the window opening 10 on the surface of the paper 9.

  FIG. 3 shows a plane of an example of an anti-counterfeit paper embodiment using stripe-type and patch-type “spot” transfer foils using multicolor holograms and a cross section of stripe-type transfer foil 15 using multicolor hologram security. The transfer foil is adhered to the surface of the anti-counterfeit paper 19 by the adhesive layer 12.

  Substrate (2) is semi-synthetic or synthetic resin film of cellophane, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polyphenylene ether, liquid crystal polymer, polyvinyl chloride, polyester, polyamide, polycarbonate, polyethyl methacrylate, polystyrene, etc. Can be used as a single layer or a composite. Furthermore, it is preferable to select a material that does not melt or soften in the drying zone of the paper machine, and usually has a property of not sticking at 90 to 110 ° C. If the thickness of the base material is too thin, various processing becomes difficult, and if it is too thick, when the thread is made between the paper layers, the thickness of the paper partially increases and causes various problems. The thickness of the substrate is preferably 5 μm to 25 μm.

  In the state of the anti-counterfeit paper 19 or the anti-counterfeit printed matter in which the thread is engraved between the paper layers, the base material (2) is preferably not visually recognized from the appearance. A substrate can be mentioned. Even a very lightly colored chromatic substrate can be used if the object of the present invention can be achieved. In the present invention, as a representative example, a transparent polyester film having a large physical strength and being chemically stable can be suitably used.

  The relief-type hologram or the relief-type diffraction grating is composed of a fine concavo-convex pattern by heating and pressing the embossed layer 2 using a relief-type press plate composed of a fine concavo-convex pattern forming a hologram or a diffraction grating, respectively. The embossed pattern portion 3 is duplicated.

  The metal used for the reflective layer 5 is typically aluminum, but in addition to this, a simple substance or a mixture of metals such as tin, zinc, iron, nickel, chromium and cobalt can be used. The thickness of the metal deposition layer is usually 250 to 1000 angstroms.

  The colored layer 6 is formed by forming an ink mainly composed of a coloring material and a resin into a desired pattern using an appropriate printing technique. As coloring materials, not only coloring dyes and pigments, but also fluorescent materials, pearl pigments, and materials that absorb in the infrared and ultraviolet regions can be used. Can be easily formed. The colored layers 6 may have the same hue or different hues. Moreover, this base material is immersed in an alkaline aqueous solution or an acidic aqueous solution (that is, subjected to a demetalizing process), and the reflective layer 5 made of metal vapor deposition in a portion other than the colored layer 6 is dissolved.

  The colored layer 6 can be provided by offset printing, gravure printing, screen printing, flexographic printing, inkjet printing, or the like. Usually, the printing thickness is 0.5 μm to 3 μm.

  The transmittance of the main peak of the colored layer is preferably in the range of 70 to 90%. If it is 90% or more, the coloring is difficult to visually recognize, and if it is 70% or less, the reflected light from the metal reflection layer is shielded and difficult to visually recognize. The transmittance can be measured with a spectrophotometer.

If necessary, other target layers such as an anchor layer for improving the adhesion between the protective layer 8 and the interlayer and an adhesive layer for stably providing threads in the paper can be provided as appropriate. Acrylic for demetalizing processing Series resins can be used. If an example of a composition of the protective layer 8 is shown, acrylic polyol resin (MCA4039 (made by DIC Corporation) 15 weight part), isocyanate hardening | curing agent (Duranate 24A100 (made by Asahi Kasei Corporation) 5 weight part), methyl ethyl ketone (40 weight) Part), toluene (30 parts by weight), and polyethylene wax (additive 180 (manufactured by Toyo Ink Manufacturing Co., Ltd.) 10 parts by weight).

  As a material of the adhesive layer 12, a general adhesive material can be used as long as it does not affect the substrate 1. For example, vinyl chloride-vinyl acetate copolymer, polyester polyamide, acrylic, butyl rubber, natural rubber, silicone, polyisobutyl adhesive layer alone or alkyl methacrylate, vinyl ester, acrylonitrile, styrene, vinyl monomer Necessary additives such as coagulation components such as unsaturated carboxylic acids, hydroxy group-containing monomers, acryl nitriles, and other reforming components, polymerization initiators, plasticizers, curing agents, curing accelerators, and antioxidants What was added according to it can be used.

  Using the micro slitter device, the security thread 14 of the present invention is completed by slitting with a predetermined width according to a conventional method. The width of the thread is usually 0.5 mm to 10 mm.

  An example of a method for manufacturing the paper 9 will be described. The preparation of paper stock is mainly made of paper pulp such as softwood bleached kraft pulp (NBKP), hardwood bleached kraft pulp (LBKP), softwood bleached sulfite pulp (NBSP), thermomechanical pulp (TMP), beater, disc refiner, etc. Beating treatment using this, various fillers such as clay, kaolin, calcium carbonate, titanium dioxide, aluminum hydroxide, paper strength enhancer, sizing agent, yield improver, antifoaming agent, coloring dye, coloring pigment, A paper material is prepared by appropriately using a fluorescent whitening agent, a fixing agent, and the like.

  The anti-counterfeit paper 19 of the present invention can be manufactured using a conventionally known method. As described above, there are roughly two types of paper with security thread 14. One is a type in which the security thread 14 is engraved inside the paper and is not exposed on the surface of the paper, and the other is “paper with open window thread” in which a part of the thread is intermittently exposed on the paper surface. It is called. The anti-counterfeit paper 19 of the present invention may be any of these, but “paper with open window thread” exhibits the features of the security thread 14 of the present invention to the maximum extent.

  In the former method, the nozzle is inserted into the flow of the stock in the slice portion of the long net paper machine, the thread is fed while water is passed through the nozzle, and the thread is formed in the web formed on the paper net. , A method in which a thread insertion device is installed in the stock flowing out of the flow box of the long net paper machine, and the thread is made in a non-contact state by an air flow. Using a circular mesh paper machine with two or more layers, sending threads between paper layers using pipes with irregularities on the inner wall, and making threads between paper layers, etc. Can be adopted. Needless to say, methods other than these methods may be employed in the present invention.

The transfer foils 15 and 16 are transferred onto the surface of the anti-counterfeit paper 19 with the base material 1 removed via the adhesive layer 12. The peeling layer 11 is provided on the substrate 1, and the embossed layer 2 is formed thereon by coating. The embossing, the reflecting layer 5 formation, the colored layer 6, and the etching process of the reflecting layer 5 without the colored layer 6 are the process of manufacturing a thread. Is the same. After the pattern formation, a release adhesive layer 13 is provided, and the release adhesive layer 13 is photocured by irradiating ultraviolet rays from the substrate 1 to obtain a photocured release adhesive layer 18.
The urethane acrylate adhesive UV-7008B (manufactured by Nippon Synthetic Chemical Co., Ltd.) was used as the material of the release adhesive layer 13 forming the meta-cured release layer 18, but it exhibits good release characteristics and abrasion resistance.

[Manufacture of stripe transfer foil]
As a substrate, a 12 μm thick transparent polyester film (manufactured by Toray Industries, Inc.) was used, and metal aluminum was deposited on both sides in accordance with a conventional method using a vacuum vapor deposition device by 50 nm (nanometers). An alkali resistant resin ink layer colored using a gravure printing machine was provided on metal aluminum. Blue coloring layer (100 parts by mass of acrylic resin for demetalizing processing is mixed with 20 parts by mass of blue dye: Oreosol Blue (manufactured by Sumitomo Chemical)) Red coloring layer (red dye: Oreosol First Red (Sumitomo Chemical) 15 parts by mass)) Yellow colored layer (yellow dye: Oreosol Firth Yellow 2G (manufactured by Sumitomo Chemical Co., Ltd.) 20 parts by mass) Green colored layer (green dyes: Oreosol Blue and Oreosol Firth Yellow 2G) (Each 15 parts by mass each) and a non-colored layer (a single acrylic resin for demetalizing processing) are formed.

  Then, according to a conventional method, an aluminum hydroxide aqueous solution was used to carry out a demetalizing process, followed by washing with water, drying and winding up on a roll. Further, an ethylene-vinyl acetate-based heat-sensitive adhesive was applied to one surface with a thickness of 1.5 μm using a gravure coater to form an adhesive layer. Next, a stripe transfer foil having a width of 2 mm was produced using a micro slitter. The stripe transfer foil is wound around a bobbin.

  The stock was prepared by adding 25 parts by mass of NBKP and 75 parts by mass of LBKP to 350 ml freeness. S. F. This was beaten into 10 parts by weight of white clay, 5 parts by weight of titanium dioxide, paper strength enhancer: 0.4 parts by weight of Polystron (manufactured by Arakawa Chemical Industries), and sizing agent: Size Pine E (manufactured by Arakawa Chemical Industries). An appropriate amount of 1.0 part by mass and a sulfuric acid band is added to prepare a paper stock.

  The stripe transfer foil produced in Example 1 was transferred to a forgery prevention paper. The obtained anti-counterfeit paper can observe a hologram having metallic luster, red, blue, yellow and green colors.

DESCRIPTION OF SYMBOLS 1 ... Base material 2 ... Embossed layer 3 ... Embossed pattern part 4 ... Non-embossed pattern part 5 ... Reflective layer 6 ... Colored layer 7 ... Demeta part 8 ... Protection Layer 9 ... Paper 10 ... Window opening 11 ... Release layer 12 ... Adhesive layer 13 ... Release adhesive layer 14 ... Security thread 15 ... Stripe type transfer foil 16 ... Patch-type “spot” transfer foil 17... UV ray 18 .. Photocured release adhesive layer 19. Anti-counterfeit paper X... Security thread cross section Y... Stripe type transfer foil cross section

Claims (5)

  An optical sheet comprising a metal reflective layer on an embossed layer forming an optical element, and further provided thereon a plurality of colored layers having different colors.   The optical sheet according to claim 1, wherein the light transmittance of the colored layer is in the range of 70 to 90%.   The optical sheet according to claim 1, wherein the metal reflective layer is formed only in the colored layer region.   The optical sheet according to any one of claims 1 to 3, wherein a protective layer is provided on the metal reflective layer, the embossed layer, and the colored layer.   An anti-counterfeit paper, wherein the optical sheet according to any one of claims 1 to 4 is transferred to a paper sheet.