Authenticity of printed materials

Abstract

The present invention provides a genuineness-determinating printed material in which the color-changing properties of a luminous material and the color change of visible emission caused by excitation light do not interfere with each other, and through the synergistic effect of both, machine readability is possible even with a small amount of light-emitting material, without hindering the visibility of the luminous material. [Solution] The present invention relates to a truth-discriminating printed material that performs truth-discrimination based on emission of excitation light in a predetermined wavelength range when a discrimination region formed by printing is irradiated with excitation light, wherein the discrimination region consists of a first luminous luminescent layer formed of a first luminous luminescent ink containing a luminescent element that emits light in a predetermined wavelength range different from the excitation light, and a luminous material whose reflectance peak wavelength is a first maximum wavelength, and the first maximum wavelength is different from at least one of the maximum wavelengths of a second maximum wavelength, which is the excitation peak wavelength of the excitation light, and a third maximum wavelength, which is the peak wavelength of emission from the luminescent element.

Description

Technical Field

[0001] The present invention relates to a genuine / fake discrimination printed matter using a light-emitting body.

Background Art

[0002] It is required to endow valuable printed matters such as banknotes, passports, stamps, postage stamps, securities, identity certificates, various tickets, security labels, etc. with advanced genuine / fake discrimination technologies.

[0003] Examples of genuine / fake discrimination technologies include a technology of forming a phosphorescent image with an ink containing a phosphorescent material and visually confirming the color change of the phosphorescent image according to the viewing angle, or a method of forming a luminescent image with a fluorescent ink containing a light-emitting body that emits fluorescence by irradiation with ultraviolet rays, visible light or infrared light, and reading the fluorescence of the luminescent image with a detector. Among these, in particular, a method of endowing a light-emitting body that emits light in the near-infrared region invisible to the human eye and discriminating the genuine / fake by detecting this emission with a reading device is highly confidential and effective.

[0004] As an example thereof, a fluorescent pigment whose fluorescence emission color tone changes by irradiation with ultraviolet rays or infrared rays, an anti-counterfeiting ink characterized by containing a phosphorescent material, and a printed matter using the anti-counterfeiting ink are disclosed (for example, refer to Patent Document 1).

Prior Art Documents

Patent Documents

[0007] Therefore, the present invention provides an ink and printed material that uses a luminescent material and a light-emitting element in combination, which allows for the machine to read even with a small amount of light-emitting element due to the synergistic effect of the two, without interfering with each other's properties of the luminescent material's color change and the visible emission color change caused by excitation light, and without hindering the visibility of the luminescent material. [Means for solving the problem]

[0008] The present invention relates to a truth-discriminating printed material that performs truth-discrimination based on emission of excitation light in a predetermined wavelength range when a discrimination region formed by printing is irradiated with excitation light in a predetermined wavelength range different from the excitation light, wherein the discrimination region consists of i) a first luminous luminescent layer formed of a first luminous luminescent ink containing a light-emitting element that emits light in a predetermined wavelength range different from the excitation light and a luminous material whose peak reflectance wavelength is a first maximum wavelength, or ii) a second luminous luminescent layer which is laminated with a first luminous layer formed of a first luminous ink containing a light-emitting element that emits light in a predetermined wavelength range different from the excitation light and a first luminous layer formed of a first luminous ink containing a luminous material whose peak reflectance wavelength is a first maximum wavelength, and the first maximum wavelength in i) or ii) is different from at least one of the maximum wavelengths of the excitation peak wavelength of the excitation light and the third maximum wavelength which is the peak wavelength of emission of the light-emitting element.

[0009] The present invention relates to a luminescent ink comprising a luminescent material that emits light in a predetermined wavelength range different from the excitation light when excited by excitation light in a predetermined wavelength range, a luminescent material, and a binder resin, characterized in that the first maximum wavelength, which is the peak wavelength of the reflectance of the luminescent material, is different from at least one of the maximum wavelengths of the excitation peak wavelength of the excitation light and the third maximum wavelength, which is the peak wavelength of the emission of light from the luminescent material.

[0010] The present invention relates to a luminous luminescent ink characterized in that the luminous material is a transparent pearl pigment with a reflectance of 45% or less at the wavelength of excitation light and the wavelength of emission of the light-emitting element. [Effects of the Invention]

[0011] The present invention provides a genuine-distinguishing printed material that, by using a combination of a luminous material and a light-emitting material, can increase the luminescence intensity with a small amount of light-emitting material through the synergistic effect of both, without interfering with the visibility of the color change of the luminous material or the machine readability of the light-emitting material. [Brief explanation of the drawing]

[0012] [Figure 1] Example of a printout for authenticity verification (A1) [Figure 2] An example diagram showing the spectral reflectance of pearl pigments. [Figure 3] Example of a printout for authenticity verification (A2 size) [Modes for carrying out the invention]

[0013] Next, embodiments for carrying out the present invention will be described, but the present invention is not limited thereto, and other embodiments are also included as long as they fall within the scope of the technical idea described in the claims.

[0014] (First embodiment) Figure 1 shows a genuine-false-discriminating printed material (A1) in the first embodiment. Figure 1(a) is a plan view of the genuine-false-discriminating printed material (A1). As shown in Figure 1(a), the genuine-false-discriminating printed material (A1) has a discrimination region (2) formed by a first luminous-emitting layer (6) on at least a part of the substrate (1). The margins of the substrate (1) other than the discrimination region (2) may have unique information (3) such as numbers, characters, or photographs, and a part of the unique information (3) may be laminated on the discrimination region (2) if it does not affect the luminescence of the discrimination region (2).

[0015] (discrimination area) The shape of the discrimination area (2) is not limited as long as it can be used for authenticity determination. It may be a figure, mark, etc. formed by solid printing or halftone printing, or it may be a letter, number, etc. It may be a line (curved line, straight line), a colored pattern, etc., or code information including a barcode or two-dimensional code. In addition, an overcoat may be applied to the entire surface of the substrate (1).

[0016] Next, Figure 1(b) shows a cross-sectional view of the authenticity-determining printed material (A1) at A-A' in the first embodiment. The first luminous emitting layer (6) is formed of a luminescent material that emits light in a predetermined wavelength range different from the excitation light, and a first luminous emitting ink containing a luminescent material that does not hinder the effects of the excitation light and emission.

[0017] (Luminous object) The light-emitting material that constitutes the first luminous light-emitting layer (6) is not particularly limited as long as it is a light-emitting material that emits light in a predetermined wavelength range different from the excitation light when excited by excitation light in a predetermined wavelength range, and known light-emitting materials can be used. The excitation light may be in the ultraviolet region, the visible light region, or the infrared region. Furthermore, the light-emitting material used in the present invention may be one type or two or more types may be mixed and used, and upconversion materials that are light-emitting materials that absorb near-infrared light and emit visible light are also included. Next, an example of a light-emitting material is given.

[0018] Examples of light-emitting materials include organic fluorescent materials such as arylamine derivatives, anthracene derivatives (phenylanthracene derivatives, etc.), pentacene derivatives, azole derivatives (oxadiazole derivatives, oxazole derivatives, triazole derivatives, benzoxazole derivatives, benzoazotriazole derivatives, etc.), thiophene derivatives (oligothiophene derivatives, etc.), carbazole derivatives, diene derivatives (cyclopentadiene derivatives, tetraphenylbutadiene derivatives, etc.), distyrylbenzene derivatives, distyrylpyrazine derivatives, distyrylarylene derivatives, stilbene derivatives, silole derivatives, and spiro compounds. Examples of phosphors and rare earth complexes include triphenylamine derivatives, trifumannylamine derivatives, pyrazoloquinoline derivatives, hydrazone derivatives, pyrazole derivatives, pyrazoline derivatives, pyridine derivatives, pyrrole derivatives (porphyrin derivatives, phthalocyanine derivatives, etc.), fluorene derivatives, phenanthroline derivatives, pyrene derivatives, phenanthrene derivatives, perinone derivatives, perylene derivatives, phenylene compounds, rhodamines, coumarin derivatives, naphthalimide derivatives, benzoxazinon derivatives, quinazolinone derivatives, quinophthalone derivatives, rubrene derivatives, quinacridone derivatives, and others.

[0019] Examples of inorganic fluorescent materials include ZnS:Ag,Al, CaMgSi2O6:Eu, and BaMgAl 10 O 17 :Eu, CaWO4, (SrCaBaMg)5(PO4)3Cl:Eu, ZnS:Cu,Al, LaPO4:Ce,Tb, Gd2O2S:Tb, BaAl 12 O 19 :Mn,Zn2SiO4:Mn,Y3Al5O 12 :Ce, (Y,Gd)BO3:Tb, Y2O2S:Eu, YVO3:Eu, Y2O3:Eu, (Y,Bi)VO4:Eu, (Y,Gd)BO3 :Eu, (ZnCd)S:Ag, ZnCd)S:Cu, Cd2B2O5:Mn, (SrMg)3(PO4)2:Mn, ZnS:Ag, etc.

[0020] As a light emitter that emits light in the infrared wavelength range, Nd 0.5 Yb 0.2 Na5(WO4)4 and Nd0.9 Yb 0.1 Na5(MoO4)4, Nd 0.1 Yb 0.1 Gd 0.1 Y 0.7 PO4, Li(Nd, Yb)P4O 12 , (Lu, Yb, Nd)2O2S, Ca k (D1)(A 1-x-y , Nd x , Yb y )2(RO4) m (D1 = Li, Ag, Al, Ga, In, A = Sc, Y, La, Gd, Lu, Al, Ga, In, R = Mo, W, V), Y 0.84 Yb 0.15 Er 0.01 F3, NaY 0.69 Yb 0.30 Er 0.01 F4, BaY 1.34 Yb 0.60 Er 0.06 F4, Y 0.74 Yb 0.25 Er 0.01 OCl, Y 0.65 Yb 0.35 Tm 0.001 F 3、 A 1-x-y Nd x Yb y PO4 (where A is at least one element selected from Al, Bi, B, In, Ga, Sc, Gd, Ce, Y, Lu, La, 0 ≦ x ≦ 0.9, 0 ≦ y ≦ 0.9, 0 < x + y ≦ 1), LiNdP4O 12、 E 2-r-s Nd r Yb s Ca(MoO4)8, RE2O2CO3:Nd (RE = La, Gd, Y), AQO3:X, Y, Z (A = Ca, Sr, Ba, Q = Ti, Zr, X = Nd, Yb, Y = Al, Ga, In, Z = Sc, Y, Gd, Lu, La), As an upconversion phosphor, Y 0.84 Yb 0.15 Er 0.01 F3, NaY 0.69 Yb 0.30 Er 0.01 F4, BaY 1.34 Yb 0.60 Er 0.06 F4, Y 0.74Yb 0.25 Er 0.01 OCl, Y 0.65 Yb 0.35 Tm 0.001 F 3、 CaAl2O 19 :Er 3+ ,Yb 3+ YTa7O 19 :Er 3+ ,Yb 3+ These include:

[0021] Other luminescent materials include cyanine dyes such as indocyanine-based green, PREX710 (xanthene-based), near-infrared fluorescent dyes (manufactured by Cosmo Bio Co., Ltd.), aminobenzopyranoxanthene-based dyes (ABPX), Donor-Acceptor-Donor (dAd) type dyes, N-hydroxysuccinimide, organic phosphors of TPA radical derivatives, single-walled carbon nanotubes, carbon oxide nanotubes, quantum dots such as PbS, PbSe, and HgSe / Te.

[0022] (Glitter material) The luminous material that constitutes the first luminous emitting layer (6) can be a material such as glass flakes, mica powder, metal oxide flakes, or liquid crystal flakes, or a pearl pigment. The pearl pigment is preferably one that imparts design appeal and does not hinder excitation light or luminescence, and is particularly preferably a transparent pearl pigment that is transparent under diffuse reflected light. The transparency of the transparent pearl pigment can be expressed by the ΔL value. The higher the ΔL value, the higher the transparency, and a ΔL value of 20 or more is sufficient. The ΔL value of the transparent pearl pigment is determined by the lightness L* of the coating included in the black / white coating test chart. The measurement is performed using a suitable measuring instrument in the CIEL*a*b* color space, for example, a colorimeter (a variable-angle spectrophotometer GCMS-3 manufactured by Murakami Color Technology Laboratory Co., Ltd.). The measurement is performed on the black and white coating test charts coated in each case, with a master tone angle of 45° / 0° (irradiation angle 45°, reception 0°). The L* value is determined by substituting it into the formula, ΔL value = (L*45° / 0° / white - L*45° / 0° / black). Transparent pearl pigments can be used, which are interference-type pearl pigments in which the core layer and coating layer are not colored. These include ULTIMICA (registered trademark) from Nippon Koken Kogyo Co., Ltd., Iriodin (registered trademark), Miraval (registered trademark), Xirallic (registered trademark), Colorstream (registered trademark) from Merck KGaA, SunMICA (registered trademark), SunGEM (registered trademark) from DIC Corporation, Luminagold (registered trademark) from Luminagold, and pearl pigments from Sandream Impact.

[0023] (First-generation luminescent ink) Next, the first luminescent ink will be described. The first luminescent ink consists of at least the aforementioned luminescent material, luminescent material, and binder component, and depending on the binder, various modifiers such as photopolymerization initiators, drying agents, dispersants, gelling agents, surfactants, and lubricants may be added.

[0024] (binder) Binders include thermoplastic resins such as acrylic, maleic acid, rosin, epoxy, silicone, and butyral; oils and fats such as linseed oil, olive oil, castor oil, and sunflower oil; higher fatty acids such as linoleic acid, linolenic acid, eleostearic acid, lauric acid, myristic acid, palmitic acid, stearic acid, phlomenic acid, and hebenic acid; esters such as fatty acid esters; amides such as stearinamide and oleinamide; polyamide resins, polyester resins, epoxy resins, polyurethane resins, acrylic resins, vinyl chloride resins, cellulose resins, polyvinyl resins, petroleum resins, ethylene-vinyl acetate copolymer resins, phenolic resins, styrene resins, rosin-modified resins, tervin resins, and other resins; natural rubber; and styrene-buta resin. UV-curing resins consisting of elastomers such as diene rubber, isoprene rubber, and chloroprene rubber, as well as oligomers and monomers of acrylates and methacrylates, and as heat-melting components, can be polyester resins, vinyl chloride-vinyl acetate copolymers, saturated copolymer polyesters, (meth)acrylic resins, modified olefin polymers, allyl resins, chlorinated olefin polymers, acid-modified chlorinated olefin polymers, unsaturated carboxylic acids, urethane resins, isocyanates, ethylene-methacrylic acid copolymer resins, higher fatty acid ester acrylic copolymer resins, resol-type phenolic resins, methylolated urea resins, methylolated melamine resins, polyvinyl alcohol, polyethylene oxide, polyacrylamide, carboxymethylcellulose, etc.

[0025] (Auxiliary agents / modifiers) As auxiliary agents, photopolymerization initiators such as benzyl ketal, α-hydroxyacetophenone, α-aminoacetophenone, alkylphenone compounds, acylphosphine oxide compounds, oxime ester compounds, and titanocene compounds can be used; photosensitizers such as thioxanthone, imidazole, coumarin type, pyrazoline type, thiophene type, naphthalene type, and oxazole type; thermal polymerization inhibitors such as hydroquinone and nitrosamine; acid generators such as sulfonium salts, iodonium salts, diazonium salts, and ferrocenium salts; polyvalent metals such as cobalt, manganese, cerium, zirconium, lead, iron, zinc, copper, vanadium, barium, and calcium; oil-soluble carboxylic acids such as naphthenic acid, octylic acid, resin acid, and tall oil fatty acid; and drying agents such as salts of resin acid can be used.

[0026] As waxes, natural waxes such as whale wax, beeswax, lanolin, carnauba wax, candelilla wax, and montane wax, as well as synthetic waxes such as paraffin wax, microcrystalline wax, oxide wax, ester wax, and low molecular weight polyethylene can be used.

[0027] Polyaminoamides, hydroxyl group-containing carboxylic acid esters, acrylic block copolymers, dispersants such as alkylol ammonium salts, siloxanes, acrylic surface modifiers, adhesion promoters with acidic groups, ketones, esters, alcohol-based leveling agents, silicone-based and polymer-based defoamers, and antioxidants such as 2,4,6-tri-tert-butylphenol can be used.

[0028] Furthermore, within limits that do not inhibit luminescence, functional materials such as organic or inorganic colored pigments, magnetic materials, and chromic materials, inorganic powders such as calcium carbonate, barium sulfate, silicon dioxide, mica, kaolin, talc, and zirconia, organic particles of polymers such as polystyrene, polymethyl methacrylate, (meth)acrylic acid esters, styrene, silicone, urethane, melamine, and cellulose, and copolymers of various resins, as well as organic-inorganic composite fine particles, may be incorporated. Considering detection for authenticity determination, binder components and pigments that do not absorb light in the wavelength range corresponding to the excitation wavelength and emission wavelength of the light-emitting element used for authenticity determination are preferred, and similar attention should be paid to the absorption characteristics of the photopolymerization initiator.

[0029] The type of the first luminous ink is not particularly limited and can be used as a known ink such as offset ink, letterpress ink, flexographic ink, screen printing ink, gravure ink, intaglio ink, inkjet ink, or coating liquid. The drying or polymerization method of the varnish material is also not particularly limited and can be a known method such as penetration drying, evaporation drying, oxidative polymerization, or ionizing radiation drying. It can also be in the form of a toner or ribbon that can be applied by electrostatic transfer or thermal transfer.

[0030] (Manufacturing method) The method for manufacturing the first luminous ink is not particularly limited as long as it is a manufacturing method that can uniformly mix the aforementioned components. When mixing the components in the method for manufacturing the first luminous ink, for example, a planetary mixer, tumbler, bead mill, sand mill, stirrer, agitator, mechanical homogenizer, ultrasonic homogenizer, paint shaker, V-type blender, Nauter mixer, three-roll mill, and other mixing equipment can be used.

[0031] (Printing method) The method for applying the first luminescent ink to the substrate (1) is not particularly limited, and any known method for applying the first luminescent ink can be used, such as offset printing, letterpress printing, flexographic printing, screen printing, gravure printing, intaglio printing, inkjet printing, electrostatic transfer, thermal transfer, and all types of coatings including gravure coating. A drying process is required for the fixing of the first luminescent ink to the substrate (1), but the drying method can be selected according to the characteristics of the binder. For example, in the case of water-based gravure ink, hot air drying or natural drying is used, and in the case of UV screen ink, curing is performed by ultraviolet irradiation.

[0032] (base material) The substrate (1) is not particularly limited as long as it does not interfere with the excitation characteristics and luminescence characteristics of the light-emitting material, or the luster of the luster material, and ordinary printing substrates such as paper and plastic can be used.

[0033] Furthermore, when authenticity is determined by luminescence, the detected luminescence intensity may be affected by the light absorption characteristics of the substrate (1). For example, various colors and materials may be used as the substrate (1), and the detected luminescence intensity will change depending on the spectral characteristics of the substrate (1). For example, if the substrate (1) is white, it will show a reflectance of 50% or more in the wavelength range of 400 nm to 1200 nm, but if the substrate (1) is black, it will show a reflectance of 5% or less. Even when the same first luminescent ink is applied, luminescence may be detectable on a white substrate but not on a black substrate. In this case, in order to ensure sufficient detection even on a black substrate, it is necessary to appropriately increase the amount of luminescent material added according to the substrate.

[0034] As an example, we will describe a flexographic print produced using a UV flexographic ink composed of 10% pearl pigment, 5% CI Pigment Yellow 180, a light-emitting element, UV flexo varnish, a photopolymerization initiator, and an antifoaming agent, printed using a 140 L / inch anilox roller. When printed on a white substrate, high-quality paper (Shiraoi, manufactured by Nippon Paper Industries Co., Ltd.), the light-emitting element was detectable by machine at a concentration of 0.1%. When printed on a black substrate, black coated paper (Luminacoat Black, manufactured by Oji F-Tex Co., Ltd.), the light-emitting element was not detectable by machine at a concentration of 0.1%, but became detectable when the concentration was 1% or higher. The detector used was a small, simple detector capable of detecting the presence or absence of infrared emission using a specific wavelength between 700 nm and 900 nm as excitation light; this detector will be referred to as Detector 1.

[0035] (Increased luminescence intensity) One method for enabling detection while suppressing the amount of light-emitting material is to enhance the light-scattering properties by mixing it with organic and inorganic powders to increase the light intensity. When the light-emitting material is to be made invisible and applied to a genuine-discrimination print (A1), or when there are limitations on particle size in the printing method, such as inkjet printing, fine particles such as inorganic powders like silicon dioxide and mica, or organic particles such as acrylic or copolymer can be mixed. When the design is to be enhanced, or when printing methods that can apply coarse particles, such as screen printing or coating, can be used, pearl pigments with high gloss metallic reflection or interference colors can be mixed. These can also be used in combination.

[0036] In this section, we will explain pearl pigments, which are luminous materials. Pearl pigments have soft, beautiful interference colors that depend on the angle, and are often used in packaging. Also, due to the beauty of their interference colors and their anti-copying properties, they are used in security products such as gift certificates. By combining pearl pigments with light-emitting materials, it is possible to provide a dual security function of the pearl pigment's function and the light-emitting material's machine-readable function. Furthermore, the combined effect of the pearl pigment and light-emitting material allows for machine detection with smaller amounts of each material. In particular, since packaging often uses a high-quality black substrate, the pearl pigment, which is highly visible on a black background, and the light-emitting material, whose detection intensity decreases on black, are a complementary and effective combination.

[0037] The blending ratio of the luminescent material in the first luminescent ink is 5% to 40%, with 5% to 15% being preferable, taking into account the visual effect of the luminescent material and its influence on the light-emitting material. Depending on the spectral reflectance of the substrate (1), if the ratio is less than 5%, the visual effect of the pearl pigment will be perceived as low, and if it exceeds 40%, the effect of enhancing the luminescence intensity will have already reached a saturation point, and it will also cause a decrease in the flow characteristics and drying properties of the first luminescent ink.

[0038] Furthermore, pearl pigments have a structure in which one or more metal oxides with different refractive indices, such as titanium dioxide, are coated on a core such as mica or silicon dioxide, and the interference color differs depending on the thickness of this coating layer. The spectral reflectance of these interference colors changes in a sinusoidal curve, and the maximum and minimum wavelengths and pitch differ depending on the interference color and layer configuration. Pearl pigments in general have the effect of enhancing luminescence intensity when mixed with light-emitting materials, but the luminescence effect can be further enhanced by appropriately combining the spectral characteristics of the pearl pigment with the absorption (excitation) and emission wavelengths of the light-emitting material.

[0039] This section describes specific examples of enhancing the luminescence effect by combining the spectral characteristics of pearl pigments with the absorption (excitation) and emission wavelengths of the light-emitting material. Figure 2 shows the spectral reflectance of pearl pigments with various interference colors on a black background. As mentioned above, the spectral reflectance changes in a sinusoidal curve, and the peak wavelength of reflection differs depending on the pearl pigment with each interference color. Hereafter, the peak wavelength of reflectance in the spectral reflectance curve of the pearl pigment will be described as the "first maximum wavelength". For the pearl pigments shown in Figure 2, there are multiple excitation peak wavelengths at 250-380 nm, 420-550 nm, 580-600 nm, and 740-830 nm, and a light-emitting material (Ca) with an emission peak at 920-1100 nm. k D1( A 1-x-y ,Nd x ,Yb y )2(RO4) m An example using the method described in Japanese Patent Publication No. 2011-21161 will be explained. Hereafter, the excitation peak wavelength of the light emitter will be referred to as the "second maximum wavelength," and the emission peak wavelength of the light emitter will be referred to as the "third maximum wavelength."

[0040] In this relationship between pearl pigment and light emitter, the luminescence enhancement effect is higher when at least one of the multiple excitation peak wavelengths—the second maximum wavelength (excitation light) and the third maximum wavelength (emission wavelength)—does not overlap with the first maximum wavelength. This is because the first maximum wavelength is the wavelength at which interference light is generated due to multiple reflections at the surface and interface of the pearl pigment. When the first and second maximum wavelengths overlap, the interference effect of the pearl pigment reduces the amount of excitation light irradiated onto the light emitter, resulting in weaker luminescence. Conversely, when the first and third maximum wavelengths overlap, the luminescence from the light emitter is attenuated and weakened due to the interference effect of the pearl pigment.

[0041] When at least one of the second maximum wavelength (excitation light) and the third maximum wavelength (emission wavelength) does not overlap with the first maximum wavelength, a higher emission effect can be obtained by suppressing the attenuation of the excitation light irradiated onto the emitter and the attenuation of the emission from the emitter. It is preferable that both the second and third maximum wavelengths do not overlap with the first maximum wavelength in order to obtain strong emission from the emitter.

[0042] As described above, in order to obtain a high luminescence effect from pearl pigments, it is preferable that the reflectance of the light-emitting material is low in the excitation wavelength range or emission wavelength range. Specifically, it is preferable that the reflectance of the pearl pigment in the excitation wavelength range or emission wavelength range of the light-emitting material is 45% or less. More preferably, the reflectance of the pearl pigment in the excitation wavelength range or emission wavelength range of the light-emitting material is 40% or less, and even more preferably 30% or less.

[0043] For example, the aforementioned light-emitting material (Ca k D1( A 1-x-y ,Nd x ,Yb y )2(RO4) m In the case described in Japanese Patent Publication No. 2011-21161, the spectral reflectance plotted on the circle in Figure 2 is preferred. When using orange light around 580 nm to 600 nm as the excitation light source among several excitation wavelengths, blue pearl pigment is effective because it is a wavelength range that is transmitted without multiple reflections at the pearl surface. When using 740 nm to 830 nm as the excitation light, green pearl pigment is advantageous for the same reason. Also, when using 980 nm to 1000 nm as the excitation light, or when the reflectance of both the excitation wavelength range and the emission wavelength range is to be low, two-color pearl pigment is advantageous. In particular, if there is no need to limit the interference color of the pearl pigment for aesthetic reasons, selecting an effective combination of pearl pigments according to the characteristics of the detector of the light emitter will result in a higher emission intensity.

[0044] Here, we have explained using the reflectance of pearl pigments of each interference color shown in Figure 2 as an example, but mica powder has a similar effect. By selecting and using materials that satisfy the above conditions for the light-emitting element and the luminous material used in the first luminous luminescent material, it is possible to produce a genuine-distinguishing printed material (1) with a high luminescence effect. Furthermore, liquid crystal pigments and glass flakes can be used as luminous materials within the range that satisfies the above reflectance conditions.

[0045] (authenticity determination) This document explains how to determine the authenticity of a printed document (A1). First, the optical changes caused by the luminous material are visually observed in the discrimination area (2) of the printed document (A1) under specular reflection to confirm that it is not a copy. Next, the emission of light in the discrimination area (2) is detected using an emission detector. The emission detector is not particularly limited; it should be able to excite the light-emitting material used and detect the emission. For example, if an ultraviolet-excited visible light-emitting material is used, an ultraviolet lamp can be used as the excitation light source and the emission can be detected with a luminance meter or similar device. If an infrared light-emitting material is used, it should be excited with an LED light source appropriate to the excitation characteristics of the light-emitting material, and a detector with high detection sensitivity at the emission wavelength should be used. A camera, which is an assembly of elements, can also be used, or visible light-emitting materials can be visually inspected. The determination of authenticity can be based on the presence or absence of visible light emission, or a numerical determination can be made by setting a criterion value for visible light emission.

[0046] (Second embodiment) Next, as a second embodiment that exhibits the same effects as the first embodiment, we will describe a genuine / false discriminatory printed material (A2) having a discriminatory region (2) consisting of a first light-emitting layer (4) formed from a first light-emitting ink containing a light-emitting element that emits light in a predetermined wavelength range different from the excitation light, and a second lustrous light-emitting layer (7) which is laminated with a first lustrous layer (5) formed from a first lustrous ink containing a lustrous material that does not inhibit the excitation light and light emission. In this second embodiment, the second lustrous light-emitting layer (7) is formed by laminating the first lustrous layer (5) on the first light-emitting layer (4), but the first light-emitting layer (4) may be laminated on the first lustrous layer (5).

[0047] Note that the light-emitting element used in the first light-emitting ink that forms the first light-emitting layer (4) and the glossy material used in the first glossy ink that forms the first glossy layer (5) are the same as in the first embodiment and are therefore omitted.

[0048] Next, examples of the present invention will be shown, but these examples do not limit the embodiments of the present invention.

[0049] (Example 1) As Example 1, we will describe the authenticity-determining printed material (A1) using Figure 1, similar to the first embodiment.

[0050] First, we prepared the first luminescent ink (J1 to J6) and the comparative example (1) inks with the formulations shown in Table 1.

[0051] [Table 1]

[0052] Next, using the first luminous luminescent inks (J1 to J6) and the inks of comparative example (1), the authenticity discrimination print materials (A1-1 to A1-6) and a comparison print material (B1) shown in Table 2 were prepared. Using a printing plate with a density of 70 L / cm², a discrimination region (2) consisting of the first luminous luminescent layer (6) was created on the substrate (1), which was high-quality paper (Shiraoi, manufactured by Nippon Paper Industries Co., Ltd.), by gravure printing as a gradient pattern with an area ratio of 20% to 100%.

[0053] [Table 2]

[0054] As shown in Table 2, the discriminative region (2) of the authenticity-distinguishing printed materials (A1-1 to A1-6) beautifully demonstrated the pearl effect corresponding to the interference color of each pearl pigment.

[0055] Next, as shown in Table 2, the emission of light in the discrimination region (2) was detected by detector 1 and detector 2. As the first discrimination method, presence or absence was detected using a small, simple detector 1. As the second discrimination method, the wavelength of the light source was different from that of the first discrimination method, and excitation light of a specific wavelength of 550 nm to 600 nm was irradiated, and the emission intensity was numerically evaluated using detector 2, which is capable of numerical evaluation.

[0056] As shown in Table 2, the authenticity-discriminating printed materials of Example 1 (A1-1 to A1-6) were detectable in areas with an area ratio of 40% or more. On the other hand, the comparative printed material (B1) of Comparative Example 1 could not be detected by infrared emission in areas with an area ratio of 40% or more, but was detectable in areas with an area ratio of 60% or more. In the second discrimination method, the authenticity-discriminating printed materials (A1-1 to A1-6) had a detection value of 50 or more, while the comparative printed material (B1) of Comparative Example 1 had a low detection value of approximately 10. By setting the threshold to, for example, "40", it is possible to distinguish between genuine and counterfeit items.

[0057] Next, the first glossy ink composition (J7) and the comparative example (2) were prepared using the formulations shown in Table 3.

[0058] [Table 3]

[0059] Next, using the first luminous luminescent ink (J7) and the ink of comparative example (2), a genuine / false discrimination print (A1-7) and a comparison print (B2) were prepared. Using a 55 L / cm anilox roller plate, a pattern consisting of halftone dots with an area ratio of 80% was formed by UV flexographic printing, and a discrimination region (2) consisting of the first luminous luminescent layer (6) was prepared on the substrate (1), which is black coated paper (Luminacolor black manufactured by Oji F-Tex Co., Ltd.).

[0060] In the authenticity-distinguishing printed material (A1-7), the discrimination area (2) showed a beautiful golden pearl color. In the comparative printed material (B2) of Comparative Example 2, it was almost impossible to see the discrimination area (2) on the black substrate.

[0061] Next, when the presence or absence of the discrimination region (2) was detected using a small, simple detector 1, light emission was detected in the discrimination region (2) of Example 2, but light emission was not detected in the discrimination region (2) of Comparative Example 2.

[0062] Thus, the authenticity-distinguishing printed materials (A1-1 to A1-7) in Examples 1 and 2 of the present invention are a technology that enables detection even on substrates with high light absorption, which is unfavorable for light emission detection, with only a small amount of light-emitting material added, and that can form authenticity-distinguishing printed materials (A1) with a high level of anti-copying effect due to pearl pigment and a high level of design. [Explanation of symbols]

[0063] A1, A2 Authenticity printed matter 1 Base material 2 Discrimination area 3. Unique Information 4. First light-emitting layer 5. The first luminous layer 6. First luminous emitting layer 7. Second luminous emitting layer

Claims

1. A printable material that performs authenticity determination based on emission of excitation light in a predetermined wavelength range when a discrimination area formed by printing is irradiated, The aforementioned discrimination region is i) A first luminescent layer formed by a first luminescent ink containing a light-emitting element that emits light in a predetermined wavelength range different from the excitation light, and a luminescent material whose peak reflectance wavelength is a first maximum wavelength, or ii) A second luminous emitting layer is formed by laminating a first luminescent ink containing a luminescent element that emits light in a predetermined wavelength range different from the excitation light, and a first luminous ink containing a luminous material whose peak reflectance wavelength is a first maximum wavelength. The first maximum wavelength in i) or ii) above is A truth-discrimination printed material characterized in that the second maximum wavelength, which is the excitation peak wavelength of the excitation light, and the third maximum wavelength, which is the peak wavelength of the emission of the light emitter, are different from at least one of the maximum wavelengths.

2. A luminescent ink comprising a mixture of a light-emitting element that emits light in a predetermined wavelength range different from the excitation light in a predetermined wavelength range, a luminescent material, and a binder resin, wherein A luminous luminescent ink characterized in that the first maximum wavelength, which is the peak wavelength of the reflectance of the luminous material, is different from at least one of the maximum wavelengths of the excitation peak wavelength of the excitation light and the third maximum wavelength, which is the peak wavelength of the emission of light from the light emitter.

3. The luminous material is a transparent pearl pigment having a reflectance of 45% or less at the wavelength of the excitation light and the wavelength of emission of the light emitter, as described in claim 2.

Images