Method for producing a security element and security element

Abstract

A method for producing a security element (1) for securing data carriers or valuable documents, comprising the following steps: 1) providing a carrier substrate (2); 2) applying an embossing varnish (3), wherein the embossing varnish (3) has two areas with embossing structures (4), namely a microstructure (4a) and a diffractive structure (4b); 3) printing a soluble wash ink (5) such that the areas of the two embossing structures (4) are left unprinted. To ensure that the method is simple and economical, without negatively impacting counterfeit protection, the method according to the invention further comprises the following steps: 4) vapor deposition of a reflective layer (6) over the entire surface; 5) washing off the wash ink (5) together with the at least one layer arranged directly above the wash ink (5).

Description

AREA OF INVENTION

[0001] The present invention relates to a method for manufacturing a security element for securing data carriers or valuable documents, comprising the following steps: 1) Providing a carrier substrate; 2) Applying an embossing varnish, wherein the embossing varnish has two areas with embossing structures, namely a microstructure and a diffractive structure; 3) Printing a soluble wash ink such that the areas of the two embossing structures are left unprinted.

[0002] Furthermore, the present invention relates to a security element and to a data carrier or a document comprising the security element. STATE OF THE ART

[0003] Security features that include at least one optical element for securing data carriers or valuable documents are known from the prior art. These security features are integrated into the data carriers or valuable documents to increase their protection against forgery.

[0004] Data carriers or valuable documents are typically flat elements with two flat sides, and at least one security element can be arranged on one of these flat sides. Both the data carriers and the valuable documents can be partially transparent, in which case the security element can be located in this transparent section.

[0005] To increase protection against counterfeiting, security features in the prior art often have two optical elements.

[0006] Security devices with two optical elements are known from EP 3337675 A1. However, the manufacturing process described therein for such security devices is complex and, due to the large number of work steps and materials used, exhibits large tolerances with regard to precision and design. This not only negatively affects the counterfeit resistance of the security devices but also increases the reject rate, thereby negatively impacting the economic viability of the manufacturing process. PRESENTATION OF THE INVENTION

[0007] It is therefore an object of the present invention to provide a method for manufacturing a security element for securing data carriers or valuable documents that overcomes the disadvantages of the prior art. In particular, the method should be simple and economical without negatively affecting the counterfeit protection of the security element.

[0008] This task, in a process for manufacturing a security element to protect data carriers or valuable documents, comprises the following steps: 1) Providing a carrier substrate; 2) Applying an embossing varnish, wherein the embossing varnish has two areas with embossing structures, namely a microstructure and a diffractive structure; 3) Printing a soluble wash ink such that the areas of the two embossing structures are left unprinted; The invention solves this by further comprising the following steps: 4) full-surface vapor deposition of a reflective layer; 5) washing off the wash paint together with the at least one layer arranged directly above the wash paint.

[0009] Using the method according to the invention, a security element can be produced in a simple manner, particularly with a manageable number of steps, which is nevertheless correspondingly counterfeit-proof. Only one layer, namely the wash dye, needs to be applied precisely once.

[0010] The security element produced by the inventive method has two optical elements. To manufacture these, the embossing lacquer applied to the substrate has the two embossed structures. The embossing lacquer can be either thermoplastic or UV- or electron-beam curable. Radiation-curing embossing lacquers are particularly economical because, firstly, the embossing itself can be produced in-situ in the same process step in which the embossing lacquer is applied to the substrate, and secondly, in a (later discussed) transfer application of the security element, the desired transfer properties or adhesion can be adjusted by controlling the intensity of the radiation curing.

[0011] The embossing varnish can be applied to the entire surface of one side of the substrate, in which case a flat area of ​​the varnish is usually located outside the microstructure and the diffractive structure. However, the embossing varnish can also be applied only to partial areas of the substrate.

[0012] The imprinted structures consist of a microstructure and a diffractive structure. The imprinted structures can be adjacent to one another, or an area without an imprinted structure, i.e., a flat area, can exist between the different imprinted structures.

[0013] Within the scope of the present invention, a microstructure is understood to be a structure comprising an arrangement of protrusions and depressions forming microstructure elements, wherein the microstructure elements are characterized by a structure spacing of 1 micrometer or more. A structure spacing, also referred to as structure size, of 1 micrometer or more ensures, for example, in a safety element with such a microstructure, that this microstructure is largely achromatic, i.e., without disturbing color separation. Examples of such microstructures are micromirror structures, microlens structures, or other achromatic structures.

[0014] A diffractive structure, as used here, is understood to be a structure that diffractes incident light. This diffractive structure can be implemented, for example, as a line grating (one-dimensional) or a cross grating (two-dimensional). The dimensions of the grating-like structures, i.e., the spacing of the (one-dimensional) lines or (two-dimensional) protrusions, are on the order of the wavelength of the incident light, which is generally visible light. The diffractive structure can, for example, form a hologram, such as a surface texture hologram, or a kinegram. Diffractive structures also include those that actually have dimensions to produce diffraction effects, but whose arrangement makes them appear achromatic to the naked eye, as described, for example, in EP 4389444 A1.

[0015] The embossed varnish is then printed with the soluble wash ink in such a way that the two embossed structures form a recess in the wash ink, meaning that there is no wash ink directly over these embossed structures. Additional elements, such as mini- or micro-text, can also be printed in this process step.

[0016] The printing with the wash ink is preferably carried out using a gravure printing process, precisely aligning with the embossed structures.

[0017] The applied wash color later serves to structure the reflective layer.

[0018] Subsequently, the layer structure coated with the wash color is completely covered, i.e., both the areas with the wash color and the areas without (= embossed structures), with the reflective layer that will later serve as a reflector. In the areas of the embossed structures, the reflective layer conforms to the microstructure and the diffractive structure, so that the microstructure and the diffractive structure are preserved in the reflective layer. Preferably, the reflective layer is applied using a vacuum deposition process or by electron beam or sputtering.

[0019] In the subsequent demetallization step, the wash paint is washed away along with the layer directly above it, in this case, the reflective layer. This means that the area(s) of the overlying layer that are congruent with the area(s) of the wash paint and were previously applied to it are also washed away. The reflective layer remains in the area of ​​the two embossed structures. The resulting security element now has two optically active embossed structures, both of which carry the same reflector.

[0020] The safety element can be viewed in reflected and transmitted light. Reflected light viewing, as defined in the invention, involves illuminating the safety element from one side and viewing it from the same side. For example, the front of the safety element is illuminated and viewed. Transmitted light viewing, as defined in the invention, involves illuminating the safety element from one side and viewing it from another side, particularly the opposite side. For example, the back of the safety element is illuminated and the front of the safety element is viewed. Light thus passes through the safety element.

[0021] When viewed with reflected light, looking at the reflective layer, a micromirror effect is observed in the microstructure, and a hologram effect in the diffractive structure. Similarly, when viewed with reflected light, looking at the substrate, a micromirror effect is observed in the microstructure and a hologram effect in the diffractive structure, provided the substrate and embossing varnish are transparent. However, when viewed with transmitted light, no optical effect is visible in either the microstructure or the diffractive structure.

[0022] Preferably, both the substrate and the embossed structure are transparent. In particular, if the security element is not transferred and is to be viewed in reflected light from the side of the substrate or in transmitted light, it is essential that both the substrate and the embossed structure are transparent. Otherwise, no effects will be visible when viewed in reflected light from the side of the substrate or in transmitted light.

[0023] In general, it is noted here that the security element may be surface-treated, coated, or laminated on one or both surfaces, for example, coated or laminated with plastics, or painted, in order to protect the security features present on the security element against mechanical, physical, and / or chemical influences. A protective layer may, for example, be based on nitrocellulose, acrylates and their copolymers, polyamides and their copolymers, polyvinyl chlorides and their copolymers, or consist of a cross-linking lacquer. A protective layer may also be a film, particularly a plastic film, that is applied to the security element.

[0024] Furthermore, the security element can be coated with an adhesive layer on one or both sides to allow it to be attached to or embedded in a data carrier or valuable documents. This adhesive layer can be in the form of a heat seal, cold seal, or self-adhesive coating.

[0025] It is of course possible that the security element has more than two areas, i.e., three, four, or more areas, with each of these additional areas (i.e., the third area, fourth area, etc.) having an embossed structure. The additional areas can have the same embossed structure or different embossed structures than the first two areas, namely the microstructure and the diffractive structure.

[0026] In order to additionally generate a diverse color-shifting effect over the diffractive structure in an economical manner, one embodiment of the invention provides that the following steps are carried out between steps 4) and 5): 4a) Printing a soluble wash ink such that it is arranged only directly over the area of ​​the microstructure; 4b) full-surface vapor deposition of a dielectric layer; 4c) full-surface vapor deposition of an absorber layer.

[0027] In this process, an additional layer of wash ink is printed on, with the wash ink being placed directly over the microstructure coated with the reflective layer. Thus, the diffractive structure (and other areas) is not covered by the wash ink.

[0028] Subsequently, an optically variable coating comprising the dielectric layer and, above it, the absorber layer is vapor-deposited, both in those areas exhibiting a wash color and in those areas without a wash color, here the diffractive structure. Preferably, these two layers are each applied by electron beam or sputtering.

[0029] The wash paint is removed in a single demetallization step as described above. This means that the area(s) of the overlying layers that are congruent with the area(s) of the wash paint (which was applied in two steps) and were previously applied to the wash paint are also washed away.

[0030] The resulting safety element also has two optically active embossed structures, namely the microstructure with the reflective layer and the diffractive structure with the reflective layer, the dielectric layer and the absorber layer.

[0031] The layered structure directly above the diffractive layer is a thin-film arrangement that allows for the creation of a wide variety of color shift effects (e.g., magenta to green or green to blue), achieved through thin-film interference. The optical effect of the embossed structure combined with the overlying thin-film arrangement creates additional, non-reproducible effects, such as a motion effect with varying color impressions or a sense of depth.

[0032] As described above, a thin-film array typically comprises at least two sublayers: the dielectric layer and the absorber layer. The additional reflective layer on the other side of the dielectric layer, i.e., opposite the absorber layer with respect to the dielectric layer, reflects electromagnetic waves, such as visible light, and thus amplifies the interference effect. The dielectric layer serves as a spacer, if necessary between the reflective layer and the absorber layer. The color shift effect occurs when viewing the interference coating from the absorber layer side, i.e., when light passes through the absorber layer and onto the dielectric layer.

[0033] For the dielectric layer of the thin-film arrangement, dielectric materials with a refractive index of less than or equal to 1.65 are suitable, e.g., aluminum oxide (Al₂O₃), metal fluorides, for example, magnesium fluoride (MgF₂), aluminum fluoride (AlF₃), silicon oxide (SiOₓ), silicon dioxide (SiO₂), cerium fluoride (CeF₅), sodium aluminum fluorides (e.g., Na₃AlF₆ or Na₅Al₃F₁₄), neodymium fluoride (NdF₅), lanthanum fluoride (LaF₅), samarium fluoride (SmF₅), barium fluoride (BaF₂), calcium fluoride (CaF₂), lithium fluoride (LiF₅), low-refractive-index organic monomers and / or low-refractive-index organic polymers.

[0034] For the dielectric layer of the thin-film arrangement, dielectric materials with a refractive index greater than 1.65 are also suitable, e.g., zinc sulfide (ZnS), zinc oxide (ZnO), titanium dioxide (TiO₂), carbon (C), indium oxide (In₂O₃), indium tin oxide (ITO), tantalum pentoxide (Ta₂O₅), cerium oxide (CeO₂), yttrium oxide (Y₂O₃), europium oxide (Eu₂O₃), iron oxides such as iron(II,III) oxide (Fe₃O₄) and iron(III) oxide (Fe₂O₃), hafnium nitride (HfN), hafnium carbide (HfC), hafnium oxide (HfO₂), lanthanum oxide (La₂O₃), magnesium oxide (MgO), neodymium oxide (Nd₂O₃). Praseodymium oxide (Pr 6 O 11 ), samarium oxide (Sm 2 O 3 ), antimony trioxide (Sb 2 O 3 ), silicon carbide (SiC), silicon nitride (Si 3 N 4 ), silicon monoxide (SiO ), selenium trioxide (Se 2 O 3 ), tin oxide (SnO 2 ), tungsten trioxide (WO 3 ), high-refractive-index organic monomers and / or high-refractive-index organic polymers.

[0035] A metallic layer can be used as the absorber layer of the thin-film arrangement, which can be, for example, a pure metal layer or a layer containing metallic clusters. Preferably, the absorber layer comprises at least one metal from the group consisting of aluminum, gold, titanium, vanadium, cobalt, tungsten, niobium, iron, molybdenum, palladium, platinum, chromium, silver, copper, nickel, tantalum, tin and / or their alloys, for example gold / palladium, copper / nickel, copper / aluminum or chromium / nickel.

[0036] Preferably, the method according to the invention does not include any further steps between steps 1), 2), 3), 4), 4a), 4b), 4c) and 5).

[0037] Alternatively, the color-shifting effect can also be produced by means of two demetallization steps. Although this entails an additional process step, it further reduces the reject rate, as the safety element can be manufactured even more precisely. Therefore, in a further embodiment of the invention, the following steps are carried out after step 5): 5a) Printing a soluble wash ink such that the area above the diffractive structure is left unprinted; 5b) full-surface vapor deposition of a dielectric layer; 5c) full-surface vapor deposition of an absorber layer; 5d) washing off the wash paint together with the layers arranged directly above the wash paint.

[0038] In this variant, after the first demetallization step (described above), a wash color is printed on again, with the diffractive structure forming a recess in the wash color. This means that there is no wash color directly above the diffractive structure.

[0039] Here too, the printing of the wash ink is preferably carried out using a gravure printing process with precise registration to the embossed structures, in particular to the diffractive structure.

[0040] Subsequently, the dielectric layer and the overlying absorber layer are vapor-deposited, both in those areas with a wash color and in those areas without a wash color, here the diffractive structure. Preferably, these two layers are each applied by electron beam or sputtering.

[0041] The wash paint is then removed along with the layers directly above it in a further demetallization step. This means that the area(s) of the overlying layers that are congruent with the area(s) of the wash paint and were previously applied to the wash paint are also washed away.

[0042] The resulting security element also has two optically active embossed structures, namely the microstructure with the reflective layer and the diffractive structure with the reflective layer, the dielectric layer and the absorber layer.

[0043] Preferably, the method according to the invention does not include any further steps between steps 1), 2), 3), 4), 5), 5a), 5b), 5c) and 5d).

[0044] In order to additionally generate a diverse color shift effect over the microstructure in an economical manner, one embodiment of the invention provides that the following steps are carried out between steps 4) and 5): 4a) Printing a soluble wash color such that it is arranged only directly over the area of ​​the diffractive structure; 4b) full-surface vapor deposition of a dielectric layer; 4c) full-surface vapor deposition of an absorber layer.

[0045] In this process, an additional layer of wash ink is printed on, with the wash ink being placed directly over the diffractive structure coated with the reflective layer. Thus, the microstructure (and other areas) are not covered by the wash ink.

[0046] Subsequently, an optically variable coating comprising the dielectric layer and, above it, the absorber layer is vapor-deposited, both in those areas exhibiting a wash color and in those areas without a wash color, in this case, the microstructure. Preferably, these two layers are each applied by electron beam or sputtering.

[0047] The wash color is removed in a single demetallization step as described above.

[0048] The resulting security element also has two optically active embossed structures, namely the microstructure with the reflective layer, the dielectric layer and the absorber layer, and the diffractive structure with the reflective layer.

[0049] The layered structure directly above the microstructure is a thin-film arrangement, which allows for the creation of a wide variety of color shift effects (e.g., magenta to green or green to blue). These color shift effects are achieved through thin-film interference. The optical impression created by the embossed structure with the overlying thin-film arrangement produces an achromatic effect, similar to a micromirror effect, with varying color impressions depending on the viewing angle.

[0050] As described above, a thin-film array typically comprises at least two sublayers: the dielectric layer and the absorber layer. The additional reflective layer on the other side of the dielectric layer, i.e., opposite the absorber layer with respect to the dielectric layer, reflects electromagnetic waves, such as visible light, and thus amplifies the interference effect. The dielectric layer serves as a spacer, if necessary between the reflective layer and the absorber layer. The color shift effect occurs when viewing the interference coating from the absorber layer side, i.e., when light passes through the absorber layer and onto the dielectric layer.

[0051] The materials already described above are suitable for the dielectric layer and the absorber layer of the thin-film arrangement.

[0052] Preferably, the method according to the invention does not include any further steps between steps 1), 2), 3), 4), 4a), 4b), 4c) and 5).

[0053] To manufacture the safety element even more precisely, the color-shifting effect can also be achieved by means of two demetallization steps. Therefore, in a further embodiment of the invention, the following steps are carried out after step 5): 5a) Printing a soluble wash color such that the area above the microstructure is left unprinted; 5b) vapor deposition of a dielectric layer over the entire surface; 5c) vapor deposition of an absorber layer over the entire surface; 5d) washing off the wash color together with the layers arranged directly above the wash color.

[0054] In this variant, after the first demetallization step (described above), a wash color is printed on again, with the microstructure forming a recess in the wash color. This means that there is no wash color directly over the microstructure.

[0055] Here too, the printing of the wash ink is preferably carried out using a gravure printing process, with precise registration to the embossed structures, especially to the microstructure.

[0056] Subsequently, the dielectric layer and the overlying absorber layer are vapor-deposited, both in those areas with a wash color and in those areas without a wash color, in this case, the microstructure. Preferably, these two layers are each applied by electron beam or sputtering.

[0057] The wash paint is then removed along with the layers directly above it in a further demetallization step. This means that the area(s) of the overlying layers that are congruent with the area(s) of the wash paint and were previously applied to it are also washed away.

[0058] The resulting security element also has two optically active embossed structures, namely the microstructure with the reflective layer, the dielectric layer and the absorber layer, and the diffractive structure with the reflective layer.

[0059] Preferably, the method according to the invention does not include any further steps between steps 1), 2), 3), 4), 5), 5a), 5b), 5c) and 5d).

[0060] In order to ensure that the safety element is durable, a further embodiment of the invention provides that the method further comprises the following steps: 6) full-surface application of a protective layer.

[0061] As briefly mentioned above, the protective layer reliably protects the security element, particularly against environmental influences, and ensures its longevity. The protective layer can be a plastic film applied over the entire surface of the existing layers of the security element, for example, by bonding, such as with a fully applied laminating lacquer. Alternatively, the protective layer can be a coating or lacquer (especially a cross-linking lacquer) applied over the entire surface of the existing layers of the security element, and made, for example, from nitrocellulose, acrylates and their copolymers, polyamides and their copolymers, or polyvinyl chlorides and their copolymers.

[0062] This layered structure with a protective layer is particularly useful when the security element is not transferred but remains on the substrate.

[0063] If the security element is transferred after manufacture, then in a further embodiment of the invention it is provided that the following step is carried out between steps 1) and 2): 1a) full-surface application of a transfer layer.

[0064] The transfer layer is positioned between the substrate and the embossing lacquer, whereby the substrate is removed from the transfer layer during the transfer process. The transfer layer can remain either on the security element or on the substrate.

[0065] As mentioned above, instead of a separate transfer layer, the embossing varnish can be given transfer properties or adhesion, for example, through its composition and / or the type and intensity of its drying process, so that it can be detached from the substrate. In this way, a separate transfer layer and the process step for its production can be eliminated. The embossing varnish itself takes on the function of the transfer layer.

[0066] In order to be able to place the safety element on a desired substrate during the transfer process, a further embodiment of the invention provides that the method further comprises the following steps: 6) full-surface application of a heat-seal varnish.

[0067] During the transfer process, the carrier substrate is removed from the layer structure, which includes the transfer layer, the embossing varnish, the reflective layer, possibly the dielectric layer, as well as the absorber layer and the heat-seal varnish, and is arranged on a data carrier or a valuable document using the heat-seal varnish.

[0068] In one embodiment of the invention, the reflective layer is provided to be a metallic layer or an HRI layer.

[0069] If a metallic layer is used as a reflective layer, it preferably comprises at least one metal selected from the group consisting of aluminum, gold, chromium, silver, copper, tin, platinum, nickel, and their alloys, for example, nickel / chromium or copper / aluminum. It is also conceivable that the reflective layer contains a semiconductor, such as silicon. Finally, it is also conceivable that the reflective layer is produced by applying a printing ink with metallic pigments, preferably from a metal in the aforementioned group.

[0070] High Refractive Index (HRI) layers, which comprise a material with a refractive index greater than 1.5, can also be used as reflective layers. Such HRI layers, for example, contain dielectric materials with a refractive index greater than or equal to 1.65.B Zinc sulfide (ZnS), zinc oxide (ZnO), titanium dioxide (TiO₂), carbon (C), indium oxide (In₂O₃), indium tin oxide (ITO), tantalum pentoxide (Ta₂O₅), cerium oxide (CeO₂), yttrium oxide (Y₂O₃), europium oxide (Eu₂O₃), iron oxides such as iron(II,III) oxide (Fe₃O₄) and iron(III) oxide (Fe₂O₃), hafnium nitride (HfN), hafnium carbide (HfC), hafnium oxide (HfO₂), lanthanum oxide (La₂O₃), magnesium oxide (MgO), neodymium oxide (Nd₂O₃), praseodymium oxide (Pr₆O₁₁), samarium oxide (Sm₂O₃), antimony trioxide (Sb₂O₃), silicon carbide (SiC), silicon nitride (Si₃N₄), silicon monoxide (SiO₂), selenium trioxide (Se₂O₃), tin oxide (SnO₂), tungsten trioxide (WO₃), high-refractive-index organic monomers and / or high-refractive-index organic polymers. All of these materials can be vapor-deposited (especially the monomers and polymers).

[0071] Depending on the end use of the security element, special carrier substrates are used. For good adhesion of the embossing lacquer to the carrier substrate, appropriately coated or pretreated films can be used, or films with an adhesion promoter.

[0072] Therefore, in a further embodiment of the invention, it is provided that the carrier substrate is made of polyethylene terephthalate or of oriented polypropylene.

[0073] The preferred carrier substrate is made of polyethylene terephthalate.

[0074] If a permanent anchoring of the carrier substrate to the embossing varnish is desired, then polyethylene terephthalate films such as Hostaphan® RG films are preferably used, which have an optimal surface roughness and a special stretch ratio.

[0075] If oriented polypropylene, such as monoaxially oriented polypropylene (MOPP) or biaxially oriented polypropylene (BOPP), is used as a carrier substrate, then the use of a so-called adhesion promoter layer, for example a painted primer layer of 0.5 gr / m² < dry application has proven to be useful.

[0076] Such an adhesion promoter can also be used with a polyethylene terephthalate substrate.

[0077] If the security element is transferred or re-application to a second carrier substrate, so-called hot stamping foils, thermally activatable release coatings made of wax or silicone, or even untreated polyethylene terephthalate foils or oriented polypropylene foils have proven to be advantageous.

[0078] In principle, other flexible plastic films can also be used as a carrier substrate, if necessary with an adhesion promoter, for example made of polyimide (PI), polyethylene (PE), polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyetherketone (PEK), polyethyleneimide (PEI), polysulfone (PSU), polyaryletherketone (PAEK), polyethylene naphthalate (PEN), liquid crystal polymers (LCP), polyester, polybutylene terephthalate (PBT), polyamide (PA), polycarbonate (PC), cycloolefin copolymers (COC), polyoxymethylene (POM), acrylonitrile butadiene styrene (ABS), polyvinyl chloride (PVC), ethylene tetrafluoroethylene (ETFE), polytetrafluoroethylene (PTFE), polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF) and ethylene tetrafluoroethylene hexafluoropropylene fluoropolymer (EFEP).

[0079] The support substrate preferably has a thickness of 5-700 µm, preferably 5-200 µm, particularly preferably 5-50 µm.

[0080] In order to manufacture the embossing structures economically, a further embodiment of the invention provides that the two embossing structures are produced by means of a thermoplastic embossing process or by means of a radiation-curing embossing process.

[0081] If a thermoplastic embossing process is used, the thermoplastic embossing lacquer applied to the substrate is softened to a suitable temperature. The structures, i.e., the microstructure and the diffractive structure, are then embossed.

[0082] When a radiation-curing embossing process is used, a radiation-curing lacquer is applied using a roller application method, which may involve the use of special engraving rollers. Depending on the depth of the embossing structures, higher or lower quantities of lacquer are applied over the entire surface or partially, and the embossing is carried out in-line with precise registration. The power of the UV lamps is adjusted according to the thickness of the embossing lacquer layer and the depth of the embossing structures.

[0083] Furthermore, a security element for securing data carriers or valuable documents is provided, comprising a carrier substrate with an embossing varnish having two embossing structures, namely a microstructure and a diffractive structure. wherein according to the invention both embossing structures are provided with a reflective layer spatially aligned along the embossing structures, wherein the safety element is obtainable by the method according to the invention.

[0084] The safety element according to the invention has two optically active embossed structures, both of which carry the same reflector. In the microstructure area, a micromirror effect is observed when viewed in reflected light, and in the diffractive structure area, a hologram effect is observed when viewed in reflected light.

[0085] The security element according to the invention can be manufactured using a manageable number of work steps and is correspondingly counterfeit-proof despite the low manufacturing effort.

[0086] In a further embodiment of the invention, the diffractive structure above the reflective layer is provided with a dielectric layer and an absorber layer spatially aligned along the diffractive structure. The diffractive structure is retained in both the dielectric layer and the absorber layer.

[0087] In this version, the security element features a thin-film arrangement above the diffractive structure, enabling the creation of a wide variety of color-shifting effects (e.g., magenta to green or green to blue). These color-shifting effects are achieved through thin-film interference. The optical impression created by the embossed structure with the overlying thin-film arrangement generates additional, non-copyable effects, such as a motion effect with varying color impressions or depth perception, or a hologram in which the color changes depending on the viewing angle.

[0088] Above the microstructure lies only the reflective layer, so that when viewed in reflected light an achromatic effect, such as a micromirror effect, is present.

[0089] In a further embodiment of the invention, the microstructure above the reflective layer is provided with a dielectric layer and an absorber layer, both spatially oriented along the microstructure. The microstructure is retained in both the dielectric layer and the absorber layer.

[0090] In this version, the security element features a thin-film arrangement over the microstructure, which allows for the creation of a wide variety of color shift effects (e.g., magenta to green or green to blue). These color shift effects are achieved through thin-film interference. The optical impression created by the embossed structure with the overlying thin-film arrangement produces an achromatic effect, similar to a micromirror effect, with varying color impressions depending on the viewing angle.

[0091] Above the diffractive structure lies only the reflective layer, so that when viewed in reflected light, for example a hologram or a kinegram is visible.

[0092] Furthermore, it is intended that the security element will be used particularly in connection with data carriers or valuable documents; that is, the security element will be part of a valuable document or data carrier to increase protection against forgery. Of course, other applications of the security element are not excluded. BRIEF DESCRIPTION OF THE FIGURES

[0093] The invention will now be explained in more detail using exemplary embodiments. The drawings are exemplary and are intended to illustrate the inventive concept, but in no way to restrict it or even to represent it exhaustively. They show Figs. 1-3 show a longitudinal section through a first schematic embodiment for the production of a safety element according to the invention; Fig. 4 shows a longitudinal section through the safety element according to the invention of the first schematic embodiment; Fig. 5 shows a longitudinal section through a second schematic embodiment for the production of the safety element according to the invention; Fig. 6 shows a longitudinal section through a third schematic embodiment for the production of the safety element according to the invention; Fig. 7 shows a longitudinal section through a fourth schematic embodiment for the production of the safety element according to the invention; Fig. 8 shows a longitudinal section through a fifth schematic embodiment for the production of the safety element according to the invention; Fig. 9 shows a longitudinal section through a variant of the safety element according to the invention of the second or third embodiment.10. A longitudinal section through another variant of the safety element according to the invention with a transfer layer. WAYS TO IMPLEMENT THE INVENTION

[0094] A first embodiment for the production of a safety element 1 according to the invention is described in Fig. 1 bis Fig. 3 shown.

[0095] According to Fig. 1 A carrier substrate 2 in the form of a plastic film, e.g. made of polyethylene terephthalate, is coated over its entire surface with an embossing varnish 3. One surface of the embossing varnish 3 has two embossing structures 4, namely a microstructure 4a and a diffractive structure 4b. The embossing varnish is flat between the embossing structures 4.

[0096] A wash color 5 is printed onto the surface of the embossing varnish 3, which has the embossing structures 4, in such a way that the microstructure 4a and the diffractive structure 4b each form a recess in the applied wash color 5.

[0097] According to Fig. 2 The layer structure coated with the wash color 5 is fully coated with a reflective layer 6 by vapor deposition, whereby the reflective layer 6 adapts to the respective relief in the area of ​​the microstructure 4a and in the area of ​​the diffractive structure 4b.

[0098] According to Fig. 3 A demetallization step is carried out in which the printed wash ink 5 is washed off together with the reflective layer 6 directly above it. The reflective layer 6 remains in the area of ​​the microstructure 4a and in the area of ​​the diffractive structure 4b.

[0099] According to the Fig. 4 The safety element 1 of the first embodiment, as shown in the figure, is provided with a laminating varnish 9 and a protective layer 10. The safety element 1 has two optical elements: in the area of ​​the microstructure 4a, for example, a micromirror effect (when viewed with reflected light from above), and in the area of ​​the diffractive structure 4b, for example, a hologram effect. Even when viewed with reflected light from below, a micromirror effect would be visible in the area of ​​the microstructure 4a and a hologram effect in the area of ​​the diffractive structure 4b, for example, because the substrate 2 and the embossing varnish 3 are transparent. In transmitted light, the areas of the embossed structure 4, 4a, 4b would appear dark if the reflective layer 6 transmits less light than the adjacent areas without embossed structure 4, 4a, 4b, or no light at all.

[0100] Fig. 5 This represents a second schematic embodiment of the production of the safety element 1 according to the invention. The starting point here is the layer structure according to Fig. 2 , i.e., the carrier substrate 2, which is fully coated with the embossing varnish 3, wherein the surface of the embossing varnish 3 has the two embossing structures 4, 4a, 4b. The wash color 5 is located on the surface of the embossing varnish 3 such that the microstructure 4a and the diffractive structure 4b each form a recess in the applied wash color 5. The reflective layer 6 is located above the wash color 5 and above the embossing structures 4, 4a, 4b.

[0101] According to Fig. 5 A wash color 5 is now printed directly onto the area above the microstructure 4a. Subsequently, a dielectric layer 7 and then an absorber layer 8 are vapor-deposited over the entire surface of this layer structure, with both the dielectric layer 7 and the absorber layer 8 conforming to the relief in the area of ​​the diffractive structure 4b.

[0102] Then, just as in Fig. 2 / Fig. 3 A single demetallization step is performed in which the printed wash colors 5 are washed off together with the layers directly above them. In the region of microstructure 4a, only the reflective layer 6 remains, while in the region of diffractive structure 4b, the reflective layer 6, the dielectric layer 7, and the absorber layer 8 remain.

[0103] Fig. 6 Figure 1 shows a third schematic embodiment for the production of the safety element 1 according to the invention. The starting point here is the layer structure according to Figure 1. Fig. 3 , in which a demetallization step has already been carried out. The corresponding layer structure comprises the support substrate 2, the embossing varnish 3 and the reflective layer 6 located above the microstructure 4a and above the diffractive structure 4b.

[0104] A wash color 5 is printed onto the surface of the embossing varnish 3 or onto the reflective layer 6 in such a way that the diffractive structure 4b forms a recess in the applied wash color 5.

[0105] The layer structure coated with the wash color 5 is first fully coated with the dielectric layer 7 and then with the absorber layer 8 by means of vapor deposition, whereby the dielectric layer 7 and the absorber layer 8 adapt to the relief in the area of ​​the diffractive structure 4b.

[0106] In the third embodiment, a second demetallization step is then carried out in which the printed wash ink 5 is washed off together with the layers directly above it. In the region of the microstructure 4a, only the reflective layer 6 remains, while in the region of the diffractive structure 4b, the reflective layer 6, the dielectric layer 7 and the absorber layer 8 remain.

[0107] Fig. 7 Figure 1 shows a longitudinal section through a fourth schematic embodiment for the production of the safety element 1 according to the invention. The starting point here is the layer structure according to Figure 1. Fig. 2 , i.e., the carrier substrate 2 fully coated with the embossing varnish 3, wherein the surface of the embossing varnish 3 has the two embossing structures 4, 4a, 4b. The wash color 5 is located on the surface of the embossing varnish 3 such that the microstructure 4a and the diffractive structure 4b each form a recess in the applied wash color 5.

[0108] Above the wash color 5 and above the embossed structures 4, 4a, 4b is the reflective layer 6.

[0109] According to Fig. 7 A wash color 5 is now printed directly onto the area above the diffractive structure 4b. Subsequently, a dielectric layer 7 and then an absorber layer 8 are vapor-deposited over the entire surface of this layer structure, with both the dielectric layer 7 and the absorber layer 8 conforming to the relief in the area of ​​the microstructure 4a.

[0110] Then, just as in Fig. 2, Fig. 3 and Fig. 5 A single demetallization step is carried out in which the printed wash colors 5 are washed off together with the layers directly above them. In the region of the diffractive structure 4b, only the reflective layer 6 remains, while in the region of the microstructure 4a, the reflective layer 6, the dielectric layer 7 and the absorber layer 8 remain.

[0111] Fig. 8 Figure 1 shows a longitudinal section through a fifth schematic embodiment for the production of the safety element 1 according to the invention. The starting point here is the layer structure according to Figure 2. Fig. 3 , in which a demetallization step has already been carried out. The corresponding layer structure comprises the support substrate 2, the embossing varnish 3 and the reflective layer 6 located above the microstructure 4a and above the diffractive structure 4b.

[0112] A wash color 5 is printed onto the surface of the embossing varnish 3 or onto the reflective layer 6 in such a way that the microstructure 4a forms a recess in the applied wash color 5.

[0113] The layer structure coated with the wash color 5 is first fully coated with the dielectric layer 7 and then with the absorber layer 8 by means of vapor deposition, whereby the dielectric layer 7 and the absorber layer 8 adapt to the relief in the area of ​​the microstructure 4a.

[0114] Subsequently, in the fifth embodiment (just as in the third embodiment), a second demetallization step is carried out in which the printed wash ink 5 is washed off together with the layers directly above it. In the region of the diffractive structure 4b, only the reflective layer 6 remains, while in the region of the microstructure 4a, the reflective layer 6, the dielectric layer 7 and the absorber layer 8 remain.

[0115] Fig. 9 shows a variant of the safety element 1 according to the invention, of the second or third embodiment. According to Fig. 9 The resulting layer structure is provided with the laminating lacquer 9 and the protective layer 10. Here, too, the security element 1 has two optical areas, whereby (when viewed with reflected light from above) a micromirror effect occurs in the area of ​​microstructure 4a, for example, and the area of ​​diffractive structure 4b exhibits a hologram effect combined with a color-shifting effect caused by the thin-film arrangement. When viewed with reflected light from below, a micromirror effect would also be visible in the area of ​​microstructure 4a, and a hologram effect, but without a color-shifting effect, would be visible in the area of ​​diffractive structure 4b, for example, if the substrate 2 and the embossing lacquer 3 are transparent. In transmitted light, the areas of embossed structure 4, 4a, 4b would appear dark if the reflective layer 6 transmits less light than the adjacent areas without embossed structure 4, 4a, 4b, or no light at all.

[0116] The fourth and fifth embodiments also essentially correspond to the Fig. 9 However, the difference is that the thin-film arrangement is located in the region of microstructure 4a. In the region of microstructure 4a, for example, a micromirror effect combined with a color shift effect occurs, and the region of diffractive structure 4b exhibits, for example, a hologram effect.

[0117] The Fig. 10 , which shows another variant of the safety element 1 according to the invention of the second or third embodiment, corresponds with regard to the optically active embossing structures 4 of the Fig. 9 Thus, the manufacturing process of the optical elements of safety element 1 corresponds to the Fig. 10 to the in Fig. 5 oder Fig. 6 shown manufacturing process.

[0118] The fourth and fifth embodiments also essentially correspond to the Fig. 10 , however, with the difference that the thin-film arrangement is located in the region of microstructure 4a.

[0119] The in Fig. 10 However, the security element shown (1) has a significant difference from the one in Fig. 9 The security element 1 shown is transferable. For this purpose, a transfer layer 11 is arranged between the carrier substrate 2 and the embossing varnish 3. Furthermore, the layer structure is not provided with a laminating varnish 9 or a protective layer 10, but instead features a heat-seal varnish 12.

[0120] During the transfer application, the carrier substrate 2 is removed from the layer structure and the safety element 1 is placed on a desired substrate using the heat-seal lacquer 12. REFERENCE MARK LIST

[0121] 1 Safety element 2 Carrier substrate 3 Embossing lacquer 4 Embossing structure 4a Microstructure 4b Diffractive structure 5 Wash color 6 Reflective layer 7 Dielectric layer 8 Absorber layer 9 Laminating lacquer 10 Protective layer 11 Transfer layer 12 Heat seal lacquer

Claims

1. Method for producing a security element (1) for securing data carriers or valuable documents, comprising the following steps: 1) providing a carrier substrate (2); 2) applying an embossing varnish (3), wherein the embossing varnish (3) has two areas with embossing structures (4), namely a microstructure (4a) and a diffractive structure (4b); 3) printing a soluble wash ink (5) such that the areas of the two embossing structures (4) are left blank; characterized by the fact that The process further comprises the following steps: 4) full-surface vapor deposition of a reflective layer (6); 5) washing off the wash color (5) together with the at least one layer arranged directly above the wash color (5).

2. Method according to claim 1, characterized by the fact thatBetween steps 4) and 5) the following steps are carried out: 4a) printing a soluble wash color (5) such that it is arranged only directly over the area of ​​the microstructure (4a); 4b) vapor deposition of a dielectric layer (7) over the entire surface; 4c) vapor deposition of an absorber layer (8) over the entire surface.

3. Method according to claim 1, characterized by the fact that After step 5), the following steps are carried out: 5a) printing a soluble wash color (5) such that the area above the diffractive structure (4b) is spared; 5b) vapor deposition of a dielectric layer (7) over the entire surface; 5c) vapor deposition of an absorber layer (8) over the entire surface; 5d) washing off the wash color (5) together with the layers arranged directly above the wash color (5).

4. Method according to claim 1, characterized by the fact thatBetween steps 4) and 5) the following steps are carried out: 4a) printing a soluble wash color (5) such that it is arranged only directly over the area of ​​the diffractive structure (4b); 4b) vapor deposition of a dielectric layer (7) over the entire surface; 4c) vapor deposition of an absorber layer (8) over the entire surface.

5. Method according to claim 1, characterized by the fact that After step 5), the following steps are carried out: 5a) printing a soluble wash color (5) such that the area above the microstructure (4a) is spared; 5b) vapor deposition of a dielectric layer (7) over the entire surface; 5c) vapor deposition of an absorber layer (8) over the entire surface; 5d) washing off the wash color (5) together with the layers arranged directly above the wash color (5).

6. Method according to any one of claims 1 to 5, characterized by the fact that The procedure further includes the following steps: 6) full-surface application of a protective layer (10).

7. Method according to any one of claims 1 to 5, characterized by the fact that between steps 1) and 2) the following step is carried out: 1 a) full-surface application of a transfer layer (11).

8. Method according to claim 7, characterized by the fact that The procedure further comprises the following steps: 6) full-surface application of a heat-sealable lacquer (12).

9. Method according to any one of claims 1 to 8, characterized by the fact that the reflective layer (6) is a metallic layer or an HRI layer.

10. Method according to any one of claims 1 to 9, characterized by the fact that the carrier substrate (2) is made of polyethylene terephthalate or of oriented polypropylene.

11. Method according to any one of claims 1 to 10, characterized by the fact that the two embossed structures (4) are produced by means of a thermoplastic embossing process or by means of a radiation-curing embossing process.

12. Security element (1) for securing data carriers or valuable documents comprising a carrier substrate (2) with an embossing varnish (3) having two embossing structures (4), namely a microstructure (4a) and a diffractive structure (4b), characterized by the fact that Both embossing structures (4) are provided with a reflective layer (6) spatially aligned along the embossing structures (4), wherein the safety element (1) is obtainable by the method according to one of claims 1 to 11.

13. Safety element (1) according to claim 12, characterized by the fact that the diffractive structure (4b) above the reflection layer (6) is provided with a dielectric layer (7) spatially aligned along the diffractive structure (4b) and an absorber layer (8) spatially aligned along the diffractive structure.

14. Safety element (1) according to claim 12, characterized by the fact thatthe microstructure (4a) above the reflection layer (6) is provided with a dielectric layer (7) spatially aligned along the microstructure (4a) and an absorber layer (8) spatially aligned along the microstructure (4a).

15. Data carrier or security document comprising a security element (1) according to any one of claims 12 to 14.

Images