Security graphic element, data carrier containing the security graphic element, and method for producing the data carrier

Abstract

The invention relates to a security graphic element applied to part or all of a substrate that is opaque or transparent in visible light, the element comprising at least one printed area of a first type (2a, 3a) having a layer of a first ink applied thereon, and at least one printed area of a second type (2b, 3b) having a layer of a second ink applied thereon, the layer of the first ink and the layer of the second ink containing, either the same or a different, at least one iridescent pigment, and furthermore, the layer of the second ink contains at least one IR absorbing agent.

Description

[0001] Security graphic element, data carrier containing the security graphic element, and method for producing the data carrier

[0002] Technical Field

[0003] The invention relates to a security graphic element applied to a non-transparent or transparent substrate in visible light, a data carrier containing the security graphic element divided into at least two areas printed with different ink compositions, and a method for producing the data carrier. The graphic element serves as a security feature against counterfeiting or forgery, wherein IR-absorbing substances are used in the print layer, providing an effect visible during verification using devices equipped with an infrared (IR) light source, preferably in the near-infrared (NIR) range.

[0004] Background of the Invention

[0005] Valuable products, particularly valuable documents and / or secured products, means of identification, and security items such as banknotes, checks, vouchers, passports, driving licenses, tickets, identification documents, certificates of authenticity, and licenses, as well as tax stamps, security packaging, and other secured documents are vulnerable to copying, counterfeiting, and partial unauthorized modification by counterfeiters. Valuable products, data carriers, and documents of this type are protected against the above-mentioned threats by being equipped with a certain number of security features, visible and invisible to the naked eye, which serve to verify their authenticity.

[0006] Methods are known for providing security documents with optically variable features that cannot be reproduced, for example, by a photocopier or scanner, and more importantly, features that are not visible to the naked eye but are identified by means of IR light sources, especially NIR, in the process of their verification. There is still a need for improvement of such features, the identification of which is carried out using special devices containing an IR or NIR radiation source. It is especially desirable to develop security graphic elements suitable for fast, mass, machine verification of authenticity, which is achieved by giving the documents distinct, contrasting features.

[0007] Security features applied to data carriers using IR-absorbing inks (IR absorbers, preferably NIR absorbers) are a known feature of document security. They are applied in the form of microprints, relief backgrounds, ornaments, or other graphic elements. The printing utilizes inks employed in offset, intaglio, screen printing, letterpress, and other printing technologies. IR absorption by a given chemical compound means that under the influence of IR light of a specific wavelength, usually in the range of 750 nm to 1400 nm, the ink allows achieving an effect not observed in visible light (VIS) during normal observation. The IR-absorbing material absorbs electromagnetic radiation with a wavelength in the range from 750 to 1400 nm, more preferably from 800 to 1400 nm. IR absorbers are known, which, when added to inks, enable to reach printed areas that are invisible or do not show color attenuation when observed in IR readers. In visible light, under normal use, such printed areas are visible and / or are characterized by an intense color.

[0008] For the purposes of the invention, various known available chemical compounds can be used, which constitute an additive to inks or ready-made ink compositions having IR light absorption properties. IR-absorbing inks are becoming increasingly readily available on the commercial market, and therefore also available to potential counterfeiters, which creates the need for further development of this type of solution.

[0009] State of the Art

[0010] European patent application EP2087170A2 discloses a sheet containing a substrate and a security device having at least one zone with an interference effect, wherein said security device further comprises at least one tactile recognition element located in the same area as said zone with an interference effect. The zone with the interference effect contains as interference elements iridescent pigments, especially selected from among pearl mass extracts, pigments plastiques, and mica-based pigments and mixtures thereof, preferably mica coated with titanium dioxide, and / or liquid crystal-based pigments and / or a film containing one or more dielectric layers arranged between one or more reflective metal layers. Lead salts are mentioned as iridescent pigments, as well as TiCh-coated mica, also with another metal oxide, e.g., marketed by Merck AG under the name "Iriodin®".

[0011] Also, European patent application EP2203313 A2 discloses the use of iridescent pigments in a security sheet containing an iridescent security mark visible on the surface of the sheet, wherein said mark comprises at least two zones, each of which exhibits an iridescent effect, and said zones are colored in normal observation with the naked eye, and at least one of said zones contains iridescent pigments that are practically colorless in normal observation and which exhibit an opalescent effect visible only in oblique observation.

[0012] International patent application WO2013185950A1 discloses a process for producing a security feature comprising a tactile pattern, wherein said method comprises the steps of applying multiple layers of ink compositions to a substrate. These layers can be made of metameric inks. Metameric inks consist of a pair of inks formulated so that they look identical under one set of lighting conditions and / or viewing conditions but which differ and appear as different colors when any factor influencing the observed color is changed. An example of metameric colorants consists of a two-component system, i.e., a radiation- curable basecoat and a radiation-curable topcoat, one of which is made of an optically variable ink and the other of a fixed-color ink, i.e., a material with a fixed reflectance, wherein the optically variable component and the fixed-color component have a matching color at one angle and different colors at all other angles.

[0013] International patent application WO2019219250A1 discloses inks for printing security features on documents that can be machine-verified. Security inks are disclosed containing one or more IR absorbing materials selected from the group consisting of crystalline, anhydrous iron(II) orthophosphates of the general formula Fe3(PO4)2 and having the crystal structure of gratonite, crystalline, anhydrous iron(II) metal orthophosphates, crystalline, anhydrous iron(II) metal phosphonates, crystalline, anhydrous iron(II) metal pyrophosphates, crystalline, anhydrous iron(II) metal metaphosphates of the general formula FeaMetb(POc)d, wherein said security ink is an oxidation-drying security ink, a UV-curable security ink, a UV-Vis curable security ink or a combination thereof.

[0014] Security printed graphic elements containing inks with IR-absorbing components are also known from European patent applications EP1981719A1, EP1790701 and EP2027218A1.

[0015] In the field of security document printing, iridescent pigments are therefore known. This type of pigment is a transparent ink with a pearlescent sheen that gives the graphic element made with it the effect of variable color intensity depending on the viewing angle.

[0016] Pairs of inks (two inks) exhibiting a metameric effect are also known. The effect is visible when the graphic element is made using a pair of (chemically) different inks, which are almost indistinguishable under normal lighting, but exhibit color differences under different light, often in infrared radiation or under a red optical filter.

[0017] In the solutions described above, either iridescent pigments or chemical substances that are IR absorbers are used, or these components are applied in layers, however the combined use of these components in compositions of two inks (pairs of inks) to obtain a metameric effect is not described.

[0018] Essence of the Invention

[0019] The object of the invention is to provide a multi-level, previously unknown security graphic element, verified in a specific way, at a given IR wavelength and to achieve high contrast for the observed graphic elements during verification, which is desired in automatic data carrier verification methods. The object of the present invention is therefore to propose a security graphic element creating an anti-xerox security effect and / or a metameric effect in IR light. Also, the object is to propose a data carrier containing such a security graphic element and a method for its production.

[0020] The present invention refers to a security graphic element, applied to part or all of a nontransparent or transparent substrate in visible light, comprising at least one printed area of the first type, on which a layer of the first ink is applied, and at least one printed area of the second type, on which a layer of the second ink is applied, wherein the layer of the first ink and the layer of the second ink contain, the same or different, at least one iridescent pigment, and furthermore, the layer of the second ink contains at least one IR absorbing agent.

[0021] In an exemplary embodiment of the invention, the security graphic element is in the form of a single graphic image composed of a printed area of the first type and a printed area of the second type, or the printed area of the first type and the printed area of the second type, which constitute independent graphic images, or the printed area of the first type and the printed area of the second type constitute component elements of a complex graphic image.

[0022] In another embodiment, the security graphic element consists of multiple printed areas of the first type and multiple printed areas of the second type, which form a single graphic image, or constitute independent graphic images or constitute component elements of a complex graphic image.

[0023] In yet another embodiment, in the security graphic element, the iridescent pigment contained in the layer of the first ink and in the layer of the second ink is transparent or partially transparent in light incident perpendicularly to the substrate, while with a change in the observation angle it exhibits a color change in the form of a pearlescent sheen, the intensity of which depends on the observation angle.

[0024] In a further embodiment, in the security graphic element, the area of the first type has a different color than the area of the second type.

[0025] In yet another embodiment, in the security graphic element, the area of the first type contains an iridescent pigment of a different color in the layer of the first ink than the iridescent pigment contained in the layer of the second ink in the area of the second type.

[0026] Preferably, in the security graphic element, the iridescent pigment is a pigment based on natural or synthetic mica or mixtures thereof.

[0027] Preferably, in the security graphic element, the IR absorbing agent is selected from the group comprising tin-antimony grey cassiterite, copper(II) pyrophosphate, copper(II) pyrophosphate hydrate, dicopper phosphate hydroxide, SiCh coated mica, and tin-antimony grey cassiterite.

[0028] In another embodiment, the security graphic element constitutes an image of positive and / or negative aplas.

[0029] Also, the invention refers to a data carrier comprising a non-transparent or transparent substrate in visible light and applied to part or all of its surface, at least one security graphic element, characterized by the features presented above.

[0030] Moreover, the invention refers also to a method of producing a data carrier, in which at least one security graphic element, divided into areas, is printed by screen printing on part or all of the surface of a non-transparent or transparent substrate in visible light, wherein on at least one area of the first type, a layer of the first ink is applied by printing, and on at least one area of the second type, a layer of the second ink is applied by printing, wherein the layer of the first ink and the layer of the second ink contain, the same or different, at least one iridescent pigment, and furthermore, the layer of the second ink contains at least one IR absorbing agent.

[0031] Definitions

[0032] The expression "data carrier" according to the invention is understood to mean all documents, such as banknotes, personal documents, driving licenses, checks, securities, tickets, passports, as well as other valuable and secured documents that are carriers of secure information storage.

[0033] The substrate may be, for example, a paper substrate, paper-like and / or paper-like materials such as Teslin, fabric, non-woven fabric, multilayer composite substrate, polymeric, including polypropylene (PP) and / or polyamide (PA), as well as a hybrid background based on a combination of paper and polymer. The substrate may be transparent, colored, nontransparent.

[0034] The terms "first," "second," used in the description and in the patent claims are used to distinguish similar elements and not to describe a sequential or chronological order. It should be understood that the terms used in this way are interchangeable under appropriate circumstances, and that the embodiments of the invention described herein have the ability to operate in sequences other than those described or illustrated herein. According to the invention, it is possible that the security graphic element will contain an area of the first type and an area of the second type, as well as the first and second inks. It is also possible that the security graphic element will contain an area of the first type and an area of the second type, as well as subsequent areas of the first type and areas of the second type, and compositions thereof.

[0035] By printed area of the first type is meant, for the purposes of the invention, an area printed with a layer of the first ink forming a specific graphic image or a fragment thereof and the printed area of the second type is an area printed with a layer of the second ink, also forming a defined graphic image or a fragment thereof.

[0036] "Iridescent ink" refers to a transparent ink with a pearlescent sheen. A graphic element made with this ink is characterized by variable intensity, depending on the viewing angle.

[0037] The "metameric effect" refers to a graphic element made using a pair of (chemically) different inks that are nearly indistinguishable under normal lighting but exhibit color differences under different light (often in infrared radiation or under a red optical filter).

[0038] "Apla" refers to a plane entirely printed with a single ink of any color, without halftoning (without halftone dots). The result is a uniform printed surface.

[0039] For better understanding, the embodiments described in the following examples are reduced to essential basic information, and the illustrations presented in the figures are highly schematic and do not reflect real-world conditions. In particular, the proportions shown in the drawings do not correspond to real-world conditions and serve illustrative purposes only. It should be emphasized that the drawings also do not reflect the actual colors of the security element placed on the data carrier. The colors in the drawings serve only to distinguish individual elements presented in these drawings. In practical implementation, significantly more complex patterns and images, either in color or monochrome, can be used. The information provided in the following examples can be replaced by complex graphic and textual information.

[0040] The examples present preferred embodiments, but the invention should in no way be limited thereto. In particular, the different embodiments are not limited to use in the described form. For improved effects, combinations thereof are possible.

[0041] Brief description of the figures

[0042] The subject of the invention in an exemplary embodiment is shown in the drawing, in which:

[0043] Fig. 1 shows the data carrier with the applied security graphic element in the first embodiment, wherein the graphic element contains two areas printed with two types of ink, both ink types contain the same iridescent pigment, and one of the inks additionally contains an IR absorber, the upper part of Fig. 1 shows the view in visible light (VIS), and the lower part of Fig. 1 shows the view in IR light at a wavelength of 850 nm. Fig. 2 shows the data carrier with the applied security graphic element in the second embodiment, wherein the graphic element contains two areas printed with two types of ink, both ink types contain an iridescent pigment, but of different types, and one of the inks additionally contains an IR absorber, the upper part of Fig. 2 shows the view in visible light (VIS), and the lower part of Fig. 2 shows the view in IR light at a wavelength of 850 nm.

[0044] The following description provides examples of implementing the security graphic element, the data carrier, and the method of producing the data carrier having areas and ink compositions with different parameters described in this invention, thereby achieving various data carrier security effects. It should be strongly emphasized, however, that the examples described below are not intended to limit the scope of protection, but only to illustrate one of the many possible applications of this invention. This invention applies wherever a security graphic element with an anti -xerographic security effect and / or a metameric effect in IR light is required.

[0045] Detailed Description of the Invention

[0046] The data carrier comprises a non-transparent or transparent substrate in visible light, made of materials selected from the group comprising paper, cardboard, composite substrate, multilayer substrate, polycarbonate, polypropylene, polyethylene, PVC, polystyrene, fabrics, and non-woven fabrics, and having at least one security graphic element applied to its surface or both surfaces, bottom and top. The security graphic element 1 consists of at least two types of printed areas, i.e., it contains at least one printed area of the first type 2a, 3 a, on which a layer of the first ink is printed, forming a specific graphic image or a fragment thereof, e.g., in the form of a horizontal stripe (Fig. 1, Fig. 2), and at least one printed area of the second type 2b, 3b, on which a layer of the second ink is printed, also forming a defined graphic image or a fragment thereof, e.g., in the form of a second horizontal stripe, parallel to the first stripe (Fig. 1, Fig. 2). Between the area of the first type 2a, 3a, and the area of the second type 2b, 3b, or above and below these areas, there are fields 4, which can be unprinted, i.e., constitute the clean substrate of the data carrier, or can be printed using a different printing technique, a different ink, or the same printing technique. The area of the first type 2a, 3a and the area of the second type 2b, 3b are shaped so that they surround shaped surface fragments 5 (areas of clean, unprinted substrate or printed by another printing technique, another ink or the same printing technique) forming a set of letters (inscriptions, as shown in Fig. 1 and Fig. 2). The shaped surface fragments 5 are specifically defined sections covered neither by the first ink layer nor the second ink layer. They can essentially take any shape: letters, digits, filled or empty geometric shapes, fancy shapes, etc. The layer of the first ink and the layer of the second ink contain, the same or a different, at least one iridescent pigment. Furthermore, one of these layers, i.e., the layer of the second ink, contains at least one IR absorbing agent. Thus, the two mentioned ink layers always differ at least in that only one of them contains an IR absorber.

[0047] Exemplary data carriers with applied security graphic elements are shown in Fig. 1 and Fig. 2, which are in the form of a table with two rows, in which the same data carrier with the same security graphic element is shown in visible light VIS (first row) and in IR light with a wavelength of 850 nm (second row).

[0048] The figures illustrate, for illustrative purposes, in a top view, the visual effect achieved on data carriers equipped with security graphic elements, divided into at least two areas shown as lighter horizontal background stripes surrounding elements, in this case exemplary inscriptions, which are created by leaving the darker substrate unprinted in these places, which is visible in visible light (VIS), with the first area printed with the first ink shown in the upper part of each illustration with the visible inscription "Iris4Note®" (unprinted substrate fragments), and the second area printed with the second ink shown in the lower part of each illustration with the visible inscription "Metameric4Note®" (unprinted substrate fragments).

[0049] In Fig. 1, in the first embodiment of the invention, under visible light conditions (VIS, first row) the two areas in the form of the upper and lower background stripes are transparent or partially transparent in light incident perpendicularly to the substrate, whereas with a change in the viewing angle, they exhibit the same color change (a pearlescent sheen effect, the intensity of which depends on the viewing angle), i.e., the upper part of the illustration in VIS light, in the section of the horizontal background stripe, and the lower part of the illustration in the section of the horizontal background stripe have the same shade. Inks with the same iridescent pigment were used to print these areas. The identical appearance of these stripe sections of the background surrounding the unprinted parts of the substrate cannot be observed in 850 nm IR light (lower part of Fig. 2); on the contrary, the IR detector allows for detecting differences between the two areas covered with the two inks used as a pair of metameric inks.

[0050] In Fig. 2, in the second embodiment of the invention, under visible light conditions (VIS, first row), the two areas in the form of the upper and lower background stripes have indeed different colors, provided by printing with inks containing different iridescent pigments, i.e., the upper part of the illustration in VIS light, in the section of the horizontal background stripe has a yellow (yellowish) color, and the lower part of the illustration in the section of the horizontal background stripe has a green (greenish) color. Showing these two colors is not possible due to the black and white illustrations. The colors of the two different iridescent pigments are not observable (disappear) in 850 nm IR light (bottom part of Fig. 2). The IR detector allows detecting differences between the two areas covered with the two inks used as a pair of metameric inks.

[0051] The layer of the first ink and the layer of the second ink constitute layers of water-based inks, UV-curable inks, or solvent-based inks. The selection of the appropriate ink depends on the type of substrate, its absorbency, the printing machines used, etc. It is advantageous in the present invention to apply the ink layers using screen printing technology.

[0052] The basic components of water-based inks, i.e., the water base in water-based inks usually contains: one or more resins, for example selected from the group comprising acrylic resins, styrene-acrylic resins, polyurethane resins, copolymers thereof and mixtures thereof; and further components, i.e., defoamer, for example selected from the group comprising modified polysiloxane compounds; surface modifying additives selected from the group comprising polyether-modified polydimethylsiloxane; thickener, for example selected from the group comprising polyurethane-based associative thickeners (HEUR), acrylic-based associative thickeners (HASE), acrylic-based non-associative thickeners (ASE), polyether- based associative thickeners (HMPE); pH stabilizer, for example 2-amino-2-methyl-l- propanol (CAS: 124-68-5), co-solvent, for example selected from the group comprising glycols and glycol ethers, surfactants, for example selected from the group comprising fluorosurfactants; and pigment stabilizer, for example silica (CAS: 112945-52-5).

[0053] UV-curable inks, preferably for the purposes of the present invention cationic inks, usually contain one or more resins selected from the group comprising cycloaliphatic epoxides and monofunctional oxetanes; and further components, i.e., reactive diluent selected from the group comprising vinyl monomers; thickener selected from the group comprising cellulose esters; photoinitiators selected from the group comprising type I and II photoinitiators, cationic sulfonium, iodonium photoinitiators and mixtures thereof; surface additives selected from the group comprising polyether siloxane copolymer; defoamers selected from the group comprising polyolefin-based substances and copolymers thereof; ethyl 3 -ethoxypropionate - EEP (CAS: 763-69-9); propylene carbonate (CAS: 108-32-7); oligomers selected from the group comprising epoxy acrylates; and rheological additive, for example based on organophilic bentonites.

[0054] Solvent-based inks typically contain as a base 3 -methoxybutyl acetate (CAS: 4435-53-4), 2- methoxy-1 -methylethyl acetate (CAS: 108-65-6), l-ethylpyrrolidin-2-one (CAS: 2687-91- 4), 2-pyrrolidone (CAS: 616-45-5), naphtha, light aromatic hydrocarbons (CAS: 64742-95- 6), hydrodesulfurized heavy naphtha (CAS: 64742-82-1), 1 -methoxypropan -2-ol (CAS: 107-98-2), e.g., these can be commercially available bases supplied by Printcolor, Sericol.

[0055] The above-mentioned known exemplary ink bases are modified for the purposes of the invention by adding an iridescent pigment or pigments and an IR absorber or absorbers to obtain appropriate ink compositions for producing layers applied in designated areas of the security graphic element.

[0056] Despite the modification of the ink composition, it is desirable to obtain inks with the same color, which only differ in the addition of the IR absorber. Wherein, in the second variant of the invention, the inks are deliberately of different colors. The infrared absorbing chemical compound can be included in the printing ink composition which has an identical color to the second printing ink composition which does not contain the infrared absorbing chemical compound. In order to prepare a pair of metameric inks, an infrared absorbing chemical compound is added to a printing ink base, which is associated with obtaining a specific color of the ink. The color of the second printing ink base is adjusted to be identical to the composition of the first ink. This is achieved, for example, by adding matching iridescent pigments. In this way, the pair of inks under the conditions of normal visual assessment by a recipient not equipped with any special verification device is identical or very similar, difficult to distinguish in terms of color. The two ink compositions can then be applied to the substrate on selected parts of the planned graphic image so that the resulting image elements form a uniform whole - the division of the image into sections covered with the first ink and sections covered with the second ink will not be visible to the naked eye. However, when verifying the resulting image using an IR detector, only the part of the image containing the infrared absorbing chemical compound is visible.

[0057] With the use of a pair of inks exhibiting metamerism, it is possible to obtain different variants of graphic images. The images can be divided into parts, inscriptions can be created, which will be partially invisible in the IR detector, or patterns can be created that cause the image to be divided into stripes, checkerboards, etc.

[0058] According to the invention, the data carrier includes a security graphic element in the form of a layer applied (printed) onto the data carrier substrate, this layer comprises a base ink composition, such as inks selected from the group comprising aqueous inks, UV-curable inks (preferably cationically cured), and solvent-based inks, in accordance with the formulations described above.

[0059] The iridescent pigments used in the ink layers on the data carrier according to the invention are preferably pigments based on natural or synthetic mica or mixtures thereof, in micronized form, with a particle size in the range from 3 to 70 pm, preferably from 4 to 60 pm or from 4 to 50 pm, for example in the ranges: from 5 to 25 pm, from 4 to 32 pm, from 5 to 35 pm, from 6 to 48 pm, from 8 to 48 pm, from 10 to 60 pm. Exemplary iridescent pigments can be selected from the Iriodin®, Pyrisma® series supplied by Merck or from the Mearlin®, Lumina® series supplied by SunChemical.

[0060] The iridescent pigment is present in the ink composition in an amount of 8 to 25% by weight, preferably 10 to 20% by weight, for example 10 to 14% or 12 to 16% or 15 to 20% relative to the final weight of the ink composition containing all components.

[0061] The IR absorber present in the applied ink layers is preferably selected from the group of compounds comprising tin-antimony grey cassiterite (CAS: 68187-54-2), copper(II) pyrophosphate (CAS: 10102-90-6), copper(II) pyrophosphate hydrate (CAS: 15191-80-7), dicopper phosphate hydroxide (CAS: 12158-74-6), SiCh coated mica (SiCh - CAS: 14808- 60-7) and tin-antimony grey cassiterite (tin-antimony grey cassiterite - CAS: 68187-54-2). The chemical compound absorbing IR radiation is present in the ink composition in an amount of 2 to 8% by weight, preferably 3 to 6% by weight, relative to the final weight of the ink composition containing all components.

[0062] Thus, the data carrier according to the invention contains a security graphic element in the form of a layer applied to a substrate, wherein this layer contains, as a basic base, a known ink as discussed exemplarily above, and specific additives - an iridescent pigment and, on part of the security graphic element, also an IR absorber.

[0063] A chemical substance absorbing IR light (IR absorber) for the purposes of the invention is understood to mean partially absorbing IR light, and thus, for example, it absorbs less than 90% of IR light. IR light absorbing substances are known, these can be organic or inorganic compounds. IR absorption preferably occurs in the wavelength range from 750 to 1400 nm. Detection is therefore possible in the near-infrared range, for example in the range from 800 to 1300 nm, for example in the range from 800 to 1200 nm.

[0064] Infrared (IR) absorbing materials should preferably not absorb the visible range (400 nm to 700 nm) so as not to interfere with the visual effects achieved by the inks used. It is advantageous that they have a high reflectance coefficient of light in visible light. Detectors, which devices operating quickly and massively are equipped with, often rely on a very clear difference in the reflectance coefficient for selected wavelengths in the VIS and NIR ranges, and it is important to observe maximum contrasts between these optical conditions.

[0065] The NIR absorbing component at the time of detection ensures that the area covered with the ink containing it (area of the second type) has a gray to black color, which is due to the amount of IR absorber added. The higher the concentration of NIR absorber in the ink, the darker the shade upon detection.

[0066] Printing with iridescent inks is advantageous because they exhibit a pearlescent sheen effect, the intensity of which depends on the viewing angle in visible light. In addition, an IR absorber is added to one of the inks to obtain metamerism in IR, which enhances the quality of the security features. The iridescent pigment is added to the ink to achieve an anti- xerographic security effect. The products according to the invention are manufactured using screen printing technology. Examples of embodiments of the invention

[0067] The data carrier, according to the invention, comprises a paper substrate, or a polymeric substrate (polycarbonate, PVC, PET), on which two different ink compositions are applied on a flat or rotary sheet-fed or rotary web-fed screen printing machine, in at least one pass, using at least one printing module. The printed elements may have the same graphic design.

[0068] In an exemplary embodiment of the invention, the layer of the first ink (in the first area) and the layer of the second ink (in the second area) contain the same iridescent pigment, and in another embodiment of the invention, the layer of the first ink (in the first area) and the layer of the second ink (in the second area) contain different iridescent pigments, i.e., the layer of the first ink contains a first iridescent pigment, and the layer of the second ink contains a second iridescent pigment. In this embodiment of the invention, the first iridescent pigment and the second iridescent pigment differ from each other and have different colors. The layer of the second ink always contains a chemical substance that absorbs IR radiation.

[0069] Example 1 :

[0070] A security graphic element containing two print areas was applied to a paper substrate, and in the second variant to a PC substrate, by screen printing. On the first print area, a part of the security graphic element was applied by printing with the first ink, thereby forming a layer of the first ink. On the second print area, another part of the security graphic element was applied by printing with the second ink, thereby forming a layer of the second ink. The first ink and the second ink constitute a pair of inks with metameric properties. The first ink and the second ink contain the same iridescent pigment, which is transparent or partially transparent in light incident perpendicularly to the substrate, and exhibits the same color when the observation angle is changed. In addition, the second ink contains a chemical substance that absorbs radiation in the near-infrared range (NIR). Inks Al, A2 and Cl, C2 with the compositions indicated in Table A and Table C were used. Prints made with this second ink absorb IR rays in the range from 750 nm to 1400 nm. As a result, two print areas exhibiting a metameric effect are obtained - in the visible range (VIS), the area containing the layer of the first ink and the area containing the layer of the second ink are almost indistinguishable, and in infrared radiation (NIR) these two areas exhibit a color difference. The discussed Example 1 is shown schematically in Fig. 1. The upper part of Fig. 1 shows a top view of the security graphic element in visible light (VIS), and the lower part of Fig. 1 shows a top view of the security graphic element during verification using an IR detector.

[0071] The fact of IR radiation absorption (both in NIR and the entire IR) by part of the print was verified using devices equipped with, for example, filters for visible radiation reflected from the sample (e.g., ProjektinaDocubox, Regula, commercial so-called ATMs), so that the print absorbing IR radiation will appear on the image recorded by the camera as having a gray to black "color" regardless of the color it had in visible light. In this case, the part of the print made with the ink not containing a chemical substance that absorbs IR radiation will be invisible or a slight glow will be visible. On the other hand, the print made with the ink containing a chemical substance that absorbs IR radiation will be visible.

[0072] Example 2:

[0073] Analogously to Example 1, a security graphic element containing two print areas was applied to a paper or polymeric substrate by screen printing, wherein the resulting ink layers differ in the color of the iridescent pigment used. Inks Bl, B2 and DI, D2 with the compositions indicated in Table B and Table D were used. The discussed Example 2 is shown schematically in Fig. 2, wherein inks Bl, B2 were used.

[0074] Below are indicated different pairs of inks, i.e., different variants of the arrangement of two inks exhibiting metamerism in IR, contained in the security graphic element.

[0075] As an ink base, known ink components as described above were used. The IR absorber used is indicated in the last row of the tables.

[0076] As the iridescent pigment, commercially available pigments Pyrisma Yellow T30-20 Color Space Yellow (Merck), Pyrisma Green T30-24 Color Space Green (Merck) based on mica were used.

[0077] Table A

[0078] A pair of water-based inks, Al and A2, containing the same iridescent pigment.

[0079] Table B

[0080] A pair of water-based inks, Bl and B2, differing in their iridescent pigment.

[0081] Table C

[0082] A pair of cationically UV-cured inks, Cl and C2, containing the same iridescent pigment.

[0083] Table D

[0084] A pair of cationically UV-cured inks, DI and D2, differing in their iridescent pigment.

Claims

Patent Claims1. A security graphic element, applied to part or all of a substrate that is opaque or transparent in visible light, comprising at least one printed area of a first type (2a, 3a) having a layer of a first ink applied thereon, and at least one printed area of a second type (2b, 3b) having a layer of a second ink applied thereon, wherein the layer of the first ink and the layer of the second ink contain, either the same or different, at least one iridescent pigment, and further wherein the layer of the second ink contains at least one IR absorbing agent.

2. The security graphic element according to claim 1, characterized in that it is in the form of a single graphic image composed of the printed area of the first type (2a, 3 a) and the printed area of the second type (2b, 3b), or the printed area of the first type (2a, 3 a) and the printed area of the second type (2b, 3b) constitute independent graphic images, or the printed area of the first type (2a, 3a) and the printed area of the second type (2b, 3b) constitute component elements of a complex graphic image.

3. The security graphic element according to claim 1 or 2, characterized in that it consists of multiple printed areas of the first type (2a, 3a) and multiple printed areas of the second type (2b, 3b), which form a single graphic image, or constitute independent graphic images, or constitute component elements of a complex graphic image.

4. The security graphic element according to claim 1 or 2 or 3, characterized in that the iridescent pigment contained in the layer of the first ink and in the layer of the second ink is transparent or partially transparent in light incident perpendicularly to the substrate, while with a change in the observation angle, it exhibits a color change in the form of a pearlescent sheen, the intensity of which depends on the observation angle.

5. The security graphic element according to any one of claims 1 to 4, characterized in that the area of the first type (3a) has a different color than the area of the second type (3b).

6. The security graphic element according to claims 1 to 5, characterized in that the area of the first type (3a) contains, in the layer of the first ink, an iridescent pigment of a different color than the iridescent pigment contained in the layer of the second ink in the area of the second type (3b).

7. The security graphic element according to any one of claims 1 to 6, characterized in that the iridescent pigment is a pigment based on natural or synthetic mica or mixtures thereof.

8. The security graphic element according to any one of claims 1 to 7, characterized in that the IR absorbing agent is selected from the group comprising tin-antimony grey cassiterite, copper(II) pyrophosphate, hydrated copper(II) pyrophosphate, dicopper phosphate hydroxide, mica coated with SiO2, and tin-antimony grey cassiterite.

9. The security graphic element according to any one of claims 1 to 8, characterized in that it constitutes an image of positive and / or negative aplas.

10. A data carrier comprising a substrate that is opaque or transparent in visible light and having at least one security graphic element applied to part or all of its surface, characterized in that the security graphic element (1) comprises at least one printed area of the first type (2a, 3 a) having a layer of the first ink applied thereon, and at least one printed area of the second type (2b, 3b) having a layer of the second ink applied thereon, wherein the layer of the first ink and the layer of the second ink contain, the same or different, at least one iridescent pigment, and further wherein the layer of the second ink contains at least one IR absorbing agent.

11. The data carrier according to claim 10, characterized in that the security graphic element (1) is in the form of a single graphic image composed of the printed area of the first type (2a, 3 a) and the printed area of the second type (2b, 3b), or the printed area of the first type (2a, 3 a) and the printed area of the second type (2b, 3b) constitute independent graphic images, or the printed area of the first type (2a, 3 a) and the printed area of the second type (2b, 3b) constitute component elements of a complex graphic image.

12. The data carrier according to claim 10 or 11, characterized in that the security graphic element (1) consists of multiple printed areas of the first type (2a, 3a) and multiple printed areas of the second type (2b, 3b), which form a single graphic image, or constitute independent graphic images, or constitute component elements of a complex graphic image.

13. The data carrier according to claim 10 or 11 or 12, characterized in that the iridescent pigment contained in the layer of the first ink and the layer of the second ink is transparent or partially transparent in light incident perpendicularly to the substrate, while, with a change in the observation angle, it exhibits a color change in the form of a pearlescent sheen, the intensity of which depends on the observation angle.

14. The data carrier according to any one of claims 10 to 13, characterized in that the area of the first type (3a) has a different color than the area of the second type (3b).

15. The data carrier according to any one of claims 10 to 14, characterized in that the area of the first type (3a) contains, in the layer of the first ink, an iridescent pigment of a different color than the iridescent pigment contained in the layer of the second ink in the area of the second type (3b).

16. The data carrier according to any one of claims 10 to 15, characterized in that the iridescent pigment is a pigment based on natural or synthetic mica or mixtures thereof.

17. The data carrier according to any one of claims 10 to 16, characterized in that the IR absorbing agent is selected from the group comprising tin-antimony grey cassiterite, copper(II) pyrophosphate, hydrated copper(II) pyrophosphate, dicopper phosphate hydroxide, mica coated with SiO2, and tin-antimony grey cassiterite.

18. The data carrier according to any one of claims 10 to 17, characterized in that the security graphic element (1) constitutes an image of positive and / or negative aplas.

19. The data carrier according to any of claims 10 to 18, characterized in that the area of the first type and / or area of the second type completely surrounds unprinted fragments of the substrate surface.

20. A method of manufacturing a data carrier, in which at least one security graphic element (1), divided into areas, is printed by screen printing on part or all of the surface of an opaque or transparent substrate in visible light, wherein a layer of the first ink is applied,by printing, on at least one area of the first type (2a, 3a), and a layer of the second ink is applied, by printing, on at least one area of the second type (2b, 3b), wherein the layer of the first ink and the layer of the second ink contain, the same or different, at least one iridescent pigment, and further wherein the layer of the second ink contains at least one IR absorbing agent.

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