EP1798054A2 - Coded optically active security features - Google Patents

Abstract

A security mark for a data carrier, identity document, securities documents, packaging etc. incorporates an active optical feature together with a full-area or partial reflector- or mirror-layer. The security mark further incorporates an optically active element in the register, or a colored or transparent metal link layer. The metal link layer is a partial layer. The security mark has two or more metal link layers of different thickness (100-1000 nm). The reflector- or mirror layers cover the area fully or in part and are oxides of Al, Cu, Fe, Ag, Au, Pt, Pd, Sn Cr Ni or Zn and are applied e.g. as a pattern, lines, motifs or guilloche. Further claimed is a foil material bearing a commensurate security mark, and the use of the security mark in security documents, data carriers, labels, packaging and similar.

Description

The invention relates to security elements and security features, which optionally have an optically active element and a colored coding, processes for their preparation and their use.

Data carriers and documents of value, such as banknotes, identification papers or the like, or packaging materials for sensitive goods, such as electronic components, pharmaceutical products and the like, are provided with security elements, for example in the form of threads, strips, tapes, patches or other formats, for verifiability of their authenticity. The information and encodings, such as electrical conductivity, magnetic encodings, holograms or diffractive structures, characters, patterns, recesses, color and / or luminescent effects or sequences and the like having these security features, are becoming increasingly complex and expensive for increased security against counterfeiting achieve and make an exact replica almost impossible.

However, the complex information, encodings and the like, which have these security features, are usually difficult to see visually or a simple optical recognition or verifiability is not desirable. In such security features of the third stage, the verification is only complicated by machine or by special equipment possible in order to verify the authenticity of the corresponding data carrier, the value document or the packaging.

In many cases, however, it is advantageous to provide an additional visually unambiguous and recognizable feature on the data carrier, the valuable document or the packaging, which serves not only as an optional additional security feature. Furthermore, if necessary, an unambiguous assignment of the data carrier, the value document or the packaging, For example, be provided for a particular place of origin, a particular value or content, a particular brand or the like.

The object of the invention was to propose a security element which has a colored metallic or metallic appearing coding and optionally an optically variable feature.

The invention therefore relates to a security element for uniquely assignable identification and identification of data carriers, value documents and / or packaging and the like, comprising a carrier substrate, characterized in that the security element optionally an optically active feature and at least one full or partial reflector or mirror layer and has at least one in the register to the optically active element or to another security feature applied colored or transparent metal compound layer.

Another object of the invention is a film material, characterized in that it comprises a security feature, optionally an optically active feature and at least one full or partial reflector or mirror layer and at least one in register with the optically active element or to another security element applied colored or transparent metal compound layer.

In particular, in conjunction with a reflector or mirror layer results in the transparent or colored metal layer, regardless of the viewing angle, a clear color impression.

Transparent carrier foils, for example, preferably made from Pl, PP, MOPP, PE, PPS, PEEK, PEK, PEI, PSU, PAEK, LCP, PEN, PBT, PET, PA, PC, COC, are used as the carrier substrate for the security feature according to the invention. POM, ABS, PVC in question. The Carrier films preferably have a thickness of 5 to 700 .mu.m, preferably 5 to 200 .mu.m, particularly preferably 5 to 50 .mu.m.

The security feature may include an optically active feature. Optically active features are diffraction structures, diffraction structures, nanostructures, holograms, kinegrams and the like. Such structures can be produced, for example, by embossing the corresponding structure in a radiation-curable, for example UV-curable or thermoplastic lacquer.

In this case, all known embossing methods can be used.

In a preferred embodiment, the carrier substrate is coated with a radiation-curable lacquer in a coating process such as, for example, a screen-printing, gravure or flexographic printing process. The coating can be selective or full-surface.

The radiation-curable lacquer can contain, for example, a radiation-curable lacquer system based on a polyester, an epoxy or polyurethane system containing 2 or more different photoinitiators known to the person skilled in the art, which can initiate curing of the lacquer system to varying degrees at different wavelengths. Thus, for example, a photoinitiator can be activated at a wavelength of 200 to 400 nm, the second photoinitiator then activatable at a wavelength of 370 to 600 nm. Sufficient difference should be maintained between the activation wavelengths of the two photoinitiators to prevent over-excitation of the second photoinitiator while the first photoinitiator is activated. The region in which the second photoinitiator is excited should be in the transmission wavelength range of the carrier substrate used. For the main cure (activation of the second photoinitiator) electron radiation can also be used.

As a radiation-curable varnish, a water-thinnable varnish can also be used. Preference is given to polyester-based paint systems.

The impression of the surface structure, ie the diffraction, diffraction or relief structure, for example, at controlled temperature by means of a die or using a stamping die in the radiation-curable lacquer layer, which was pre-cured by activation of the first photoinitiator to the gel point and at the time of molding in this stage is located.
If a water-dilutable radiation-curable lacquer is used, it is optionally possible to precede predrying, for example by means of IR radiators.

The layer thickness of the applied radiation-curable lacquer can vary depending on the requirements of the end product and thickness of the substrate and is generally between 0.5 and 50 .mu.m, preferably between 1 and 10 .mu.m, more preferably between 1 and 5 .mu.m.

The impression of the surface structure takes place in register for the coating of the carrier substrate, wherein a tolerance of +/- 0.5 mm can be maintained. This is achieved by register control

Subsequently, the carrier material or the embossed element is partially printed with a soluble in a solvent color. In this case, the printed image is selected so that only a part of the optically active structure, or another security element is covered by the subsequent application of a layer of a metal compound.

The application of the paint can be done by any method, for example by gravure printing, flexographic printing, screen printing, digital printing and the like. The paint or ink used is soluble in a solvent, preferably water, but it may be a color soluble in any solvent, for example in alcohol, esters and the like may be used. The color or the colored lacquer can be customary compositions based on natural or artificial macromolecules. The soluble color may be pigmented or unpigmented. As pigments, all known pigments can be used. Particularly suitable are TiO ₂ , ZnS, kaolin and the like. In order to further improve the dissolution of the covered ink layer, it is also possible to apply a thin pigmented ink layer or a pure pigment layer over the whole surface or register, the thickness of this layer being approximately 0.01-5 μm.

Suitable coating materials are metal compounds, for example oxides or sulfides. Examples of metal compounds are oxides or sulfides (or chromates) of metals, in particular TiO ₂ , Cr oxides, ZnS, ITO, Bi oxide, ATO, FTO, ZnO, Al ₂ O ₃ , Zn chromate, Fe oxides, CuO and the like, or silicon oxides.
Optionally, the metal compounds may also be doped with rare earth metals. This gives in addition to the desired color in addition a luminescent effect. Furthermore, for example, copper color pigments such as azurite or malachite can be vapor-deposited.

The layer thickness of the (vapor-deposited) layer essentially depends on the desired color and is usually between 100 and 1000 nm, preferably 100 to 500 nm.
The metal compound can be applied in one or more layers, wherein the layer thickness determines the resulting color impression.

Thus, for example, a Bi oxide layer approximately at least 160-230 nm thick, as well as a TiO ₂ layer blue transparent, a ZnS layer green, a Cd layer yellow, an Al layer in conjunction with Fe ₂ O ₃ orange to purple , where the hue is controlled by the energy input. Will Cu evaporated under oxygen excess, the coating appears blue. Evaporated ZnO appears reddish transparent.

The coating is applied in a PVD or CVD process. In a PVD process, the coating is applied under vacuum (to 10 ^-12 mbar, preferably 10 ^-2 to 10 ^-6 mbar) at a temperature dependent on the vapor pressure and the thickness of the applied coating on the carrier substrate, for example by thermal evaporation, arc or Electron beam evaporation deposited. Another possibility is the application of the coating by AC or DC sputtering, wherein, depending on the thickness of the layer to be applied and the material used, the corresponding method is selected.

In a CVD process, by mixing the substance to be applied with a gas, plasma or with an activation gas, for example CO, CO ₂ , oxygen, silanes, methane, ammonia and the like, for example: caused by a ion beam, a chemical reaction and the resulting material deposited on the carrier. In this way, several reactive layers can be applied simultaneously or in parallel, on the carrier substrate creates a color effect.

Optionally, the layer bearing the optically active feature is previously treated by means of an inline plasma, corona or flame process, and then the coating according to the invention is applied either inline or in a subsequent process step in a PVD or CVD process, sputtering or the like.
High-energy plasma, for example Ar or Ar / O ₂ plasma, cleans the surface of possibly existing toning residues. As a result, the adhesion of the partial or full surface coatings is further improved. In this case, even for a partial application, the necessary sharp delimitation of the contours of the recesses, for the necessary precision the coding is necessary achieved. At the same time, the surface is activated. In this case, terminal polar groups are generated on the surface.

Optionally, simultaneously with the application of the plasma or corona or flame treatment, a thin metal or metal oxide layer can be applied as adhesion promoter, for example by sputtering or vapor deposition. Particularly suitable are Cr, Al, Ag, Ti, Cu, TiO ₂ , Si oxides or chromium oxides. This adhesion promoter layer generally has a thickness of 0.1 nm to 5 nm, preferably 0.2 nm to 2 nm, particularly preferably 0.2 to 1 nm.

In a further step, the paint application is removed by means of a solvent, optionally combined with a mechanical action. By detaching the paint application with the areas of the coating above the paint application, the desired partial coating is obtained.

In a further step, the described process can be repeated using one or more further different metal compound layers, in those areas that were not covered by the first layer or at least partially overlapping to these areas.
In this case, when viewed in transmitted or reflected light respectively, the pure shades as well as mixed colors can be generated.

Preferably, the application takes place in register, for example with an insetter method.

The coating of metal compounds can additionally have respectively defined features, for example recesses in the form of patterns, characters, lines, guilloches and the like.
Subsequently, the structure described is provided with a reflector or mirror layer. This reflector or mirror layer is made preferably of a metallic layer, for example, Al, Cu, Fe, Ag, Au, Pt, Pd, Sn, Cr, Ni, Zn, and the like.
Preferably, the optical density of the reflector or mirror layer is greater than 1.5 OD.

The coating is preferably applied in a PVD or CVD process, but it is also possible to apply it in a known printing process. If this reflector or mirror layer is to be applied only partially, the method is preferably carried out analogously to the method described above for applying a partial metal compound layer using a solvent-soluble ink.

Furthermore, coding can take place by defined application of different partial metal compound layers.

In this case, for example, in one embodiment, different metal compound layers can be applied in one plane. Preferably, these layers are then combined with a full-surface reflector or mirror layer. As a result, multicolored appearing holograms, kinegrams, nanostructures, diffraction structures and the like can be generated.

In a further embodiment, such multicolor holograms can also be produced by applying a metal compound layer in different layer thicknesses.

In a further embodiment, for example, different hologram motifs with different metal compound layers or different layer thicknesses of the same metal compound layer can be deposited. As a result, the different motifs, different colors.

The metal compound layers, as well as the reflector or mirror layer may be applied over the entire surface or partially, with unique combinations resulting from different combinations.

Furthermore, the carrier substrate can already have defined functional layers or such functional layers can subsequently be applied to the carrier substrate. These layers may, for example, have certain chemical, physical and also optical properties.

The optical properties of a further layer can be visualized by visible dyes or pigments, luminescent dyes or pigments which fluoresce or phosphoresce in the visible, in the UV region or in the IR region, effect pigments, such as liquid crystals, bronzes and / or heat-sensitive inks or pigments influence. These can be used in all possible combinations. In addition, phosphorescent pigments can also be used alone or in combination with other dyes and / or pigments.

Furthermore, it is also possible for partial electrically conductive layers to be present on the substrate, or to be applied subsequently, for example electrically conductive polymeric layers or conductive paint or lacquer layers.

To adjust the electrical properties of the applied color or the applied paint, such as graphite, carbon black, conductive organic or inorganic polymers, metal pigments (for example, copper, aluminum, silver, gold, iron, chromium and the like), metal alloys such as copper-zinc or Copper-aluminum or amorphous or crystalline ceramic pigments such as ITO, ATO, FTO and the like can be added. Furthermore, it is also possible to use doped or non-doped semiconductors, such as, for example, silicon, germanium or doped or undoped polymeric semiconductors or ionic conductors such as amorphous or crystalline metal oxides or metal sulfides can be used as an additive. Furthermore, polar or partially polar compounds such as surfactants, or nonpolar compounds such as silicone additives or hygroscopic or non-hygroscopic salts can be used or added to the paint for adjusting the electrical properties of the layer.

As a layer with electrical properties, a partial metal layer can also be applied, wherein the partial application can be effected by means of an etching process (application of a full-surface metal layer and subsequent partial removal by etching) or by means of a demetallization process.

Furthermore, an electrically conductive polymer layer can also be applied as the electrically conductive layer. The electrically conductive polymers may be, for example, polyaniline or polyethylenedioxythiophene. Particular preference is given to using PEDT / TS as the electrically conductive polymer.

To produce a layer having magnetic properties, paramagnetic, diamagnetic and also ferromagnetic materials such as iron, nickel, barium and cobalt or their compounds or salts (for example oxides or sulfides) may be used. Especially suitable are Fe (II) and Fe (III) oxides, barium or cobalt ferrites, rare earths and the like.

It is also possible to add the magnetic ink used, for example carbon black or graphite, whereby a simultaneously magnetic and also electrically conductive layer can be produced particularly advantageously in a defined coding by the method according to the invention.

Furthermore, the inventive security elements or film materials can be provided with a protective lacquer layer on one or both sides. The protective lacquer may be pigmented or unpigmented, using as pigments all known pigments or dyes, for example TiO ₂ , ZnS, kaolin, ATO, FTO, aluminum, chromium and silicon oxides or, for example, organic pigments such as pthalocyanine blue, i-indolid yellow, dioxazine violet and the like can be used. Furthermore, luminescent dyes or pigments which fluoresce or phosphoresce in the visible, in the UV range or in the IR range, effect pigments such as liquid crystals, pearlescent, bronzes and / or multilayer color change pigments and heat-sensitive inks or pigments can be added. These can be used in all possible combinations. In addition, luminescent pigments can also be used alone or in combination with other dyes and / or pigments.

Furthermore, the security element according to the invention may be provided on one or both sides with a hot or cold seal adhesive or a self-adhesive coating for application to or at least partial embedding in a substrate, which adhesive or adhesive coatings may be pigmented.

Furthermore, the security element according to the invention with one or more carrier substrates, which optionally have functional and / or decorative layers, optionally be laminated using a laminating adhesive, which laminating adhesive can also be pigmented.

The security element according to the invention is characterized by high light resistance of the color impression achieved and high security against counterfeiting. Since reflecting colors result according to the invention, the security feature according to the invention can not be reproduced by color copying The security element according to the invention can be used as easily recognizable security feature or authenticity or identification feature on data carriers, labels, in particular value documents, such as identity cards, cards, banknotes, on packaging materials in the pharmaceutical, electronics or food industry, original spare parts for cars, vehicles, aircraft become.

In the case of packaging, both the packaging and the product packed therein or, if appropriate, information which is packed with information, such as technical data sheets, instructions for use, assembly instructions and the like, are advantageously provided with a coating having a security feature with a defined color impression. As a result, both the integrity of the packaging and a possible manipulation of the contents of the packaging can be determined.

Claims (13)

Security element for uniquely assignable identification of data carriers, value documents and / or packaging and the like, characterized in that the security element optionally an optically active feature and at least one full or partial reflector or mirror layer and at least one in the register to the optically active element or to another Having security element applied colored or transparent metal compound layer. A security element according to claim 1, characterized in that the metal compound layer is a partial layer. Security element according to one of claims 1 or 2, characterized in that the security element has two or more metal compound layers. Security element according to one of claims 1 to 3, characterized in that the metal compound layer (s) has different thickness (s). Security element according to one of claims 1 to 4, characterized in that the reflector or mirror layer is a full-surface layer. A security element according to claim 1, characterized in that the metal compound layer is a full-surface layer. Security element according to one of claims 1 to 6, characterized in that the reflector or mirror layer is a partial layer. A security element according to any one of claims 1 to 7, characterized in that the metal compound layer has a thickness of 100 to 1000 nm. A security element according to any one of claims 1 to 8, characterized in that the metal compound layer of one or more layers of an oxide selected from the group of oxides of Al, Cu, Fe, Ag, Au, Pt, Pd, Sn, Cr, Ni, or Zn exists. A security element according to any one of claims 1 to 9, characterized in that the metal compound layer is in the form of patterns, characters, lines, guilloches. A security element according to any one of claims 1 to 10, characterized in that the metal compound layer is present in full tone, in halftone, or screened. Film material, characterized in that it has a security feature which optionally has an optically active feature and at least one full or partial reflector or mirror layer and at least one in the register to the optically active element or to another security element applied colored or transparent metal compound layer. Use of the security element according to one of claims 1 to 11 as security features in or on valuable documents, data carriers, labels, packaging and the like.