EP3302996B1 - Security element having a color-shifting effect - Google Patents

Description

The invention relates to a security element for value documents and data carriers with at least two different color shift effects, wherein when the viewing angle is changed, not only the color shift effect is recognizable but also an additional optical effect is created, according to the preamble of claim 1.

Security elements that exhibit a color shift effect are known.

Out of WO 02/18155 A method for the forgery-proof marking of objects is known, wherein the object is provided with a marking consisting of a first layer reflecting electromagnetic waves onto which a layer permeable to electromagnetic waves with a defined thickness is applied, after which this layer is followed by a third layer formed from metallic clusters.

Out of EP 1 716 007 B1 Security elements with optically variable layers that convey different color impressions under certain viewing angles and that have additional security levels in addition to this color shift effect in the color shift effect setup are known.

Out of WO 2006/040069 A A security element for protecting valuables with an optically variable layer is known, which also conveys different color impressions at different viewing angles. In addition, a semi-transparent color layer is arranged in a limited overlap area above the optically variable layer, the color impression of which is adapted to the color impression of the optically variable layer under predetermined viewing conditions.

Out of EP 2 420 391 A a security element with an optically variable layer that has different color impressions at different viewing angles is known, wherein a colored metallic layer is arranged in a defined area above or next to the optically variable layer, wherein the color impression of this layer is the color impression of the optically variable layer is adapted under a defined viewing angle.

Other relevant safety elements are from the WO2014/032238A1 , the WO2013/079542A2 , the DE69634139T2 , the WO2010/037638A2 , the WO2009/050448A1 , the DE102005011612A1 , the EP0105099A1 and the DE102010052665A1 known.

A security element of the type mentioned above is in the WO 2014/029263 A1 disclosed.

The object of the invention was to provide a security element which has at least two different colour shift effect areas and increased security against counterfeiting.

The invention therefore relates to a security element for banknotes, value documents and data carriers comprising a carrier substrate and a coating which has colour shift effects of the type mentioned at the outset, characterized by the features of the characterising part of claim 1.

Due to the different color shift effects arranged in the areas, which are selected according to the invention such that when the viewing angle changes, the original color of a first area appears and thus becomes visible in the adjacent area or in the area spaced apart from this first area or in an area at least partially overlapping this first area, the viewer has the impression that this color moves in a kind of rolling motion over the security element.

Carrier films, preferably flexible plastic films, for example made of PI, PP, MOPP, PE, PPS, PEEK, PEK, PEI, PSU, PAEK, LCP, PEN, PBT, PET, PA, PC, COC, POM, ABS, PVC, PTFE, ETFE (ethylenetetrafluoroethylene), PFA (tetrafluoroethylene-perfluoropropylvinylether-fluorocopolymer), MFA (tetrafluoromethylene-perfluoropropylvinylether-fluorocopolymer), PTFE (polytetrafluoroethylene), PVF (polyvinyl fluoride), PVDF (polyvinylidene fluoride), and EFEP (ethylene-tetrafluoroethylene-hexafluoropropylene-fluoroterpolymer) are suitable. The carrier films preferably have a thickness of 5 - 700 µm, preferably 5 - 200 µm, particularly preferably 5 - 50 µm. PET films are particularly preferably used as the carrier substrate.

A coating is applied to the carrier substrate, which consists of different color shift effect structures arranged next to one another in certain areas. According to the invention, these different areas are produced by printing color shift effect printing inks. Pigments that are suitable for the production of such printing inks are, for example, in WO00/31571 A , US$5,278,590 , US$5,135,812 disclosed.

Alternatively, the color shift effect can also be realized according to the invention by a layer structure containing an electromagnetic wave-reflecting layer, a polymeric or dielectric spacer layer and an absorption layer, for example a metallic layer or a layer formed from metallic clusters.

In this case, a layer that reflects electromagnetic waves is applied to the carrier substrate. This layer can preferably consist of metals, such as aluminum, gold, chromium, silver, copper, tin, platinum, nickel or tantalum, of semiconductors, such as silicon, and their alloys, for example nickel/chromium, copper/aluminum and the like, or of a printing ink with metal pigments. The thickness of the layer that reflects electromagnetic waves is preferably about 10 - 50 nm, although higher or lower layer thicknesses are also possible. The polymer or dielectric spacer layer that follows this can also be applied over the entire surface or preferably partially. However, several polymer or dielectric spacer layers can also be applied over the entire surface or partially.

These polymeric spacer layer(s) consist, for example, of conventional or radiation-curing, in particular U-curing, color or varnish systems based on nitrocellulose, epoxy, polyester, rosin, acrylate, alkyd, melamine, PVA, PVC, isocyanate, urethane or PS copolymer systems.

Layers made of S1O2, ZnS, MgF2, T'IO2 or Ta20s can be used as dielectric spacer layer(s).

The thickness of the spacer layer can be varied over a wide range, for example in a range from 10 nm to 3 µm in order to produce different coordinated color shift effects.

A full-surface or partial absorption layer made of metallic clusters is then applied to this spacer layer. The metallic clusters can consist of, for example, aluminum, gold, palladium, platinum, chromium, silver, copper, nickel, tantalum, tin and the like or their alloys, such as Au/Pd, Cu/Ni or Cr/Ni.

Alternatively, a full-surface or partial metallic layer can be applied as an absorption layer, whereby this layer can consist, for example, of metals such as aluminum, gold, chromium, silver, copper, tin, platinum, nickel or tantalum, or their alloys, for example nickel/chromium, copper/aluminium and the like, or a printing ink with metal pigments.

The areas with different color shift effects are applied next to each other. The areas can be arranged directly adjacent to each other, overlapping or in register with an unprinted area between the individual areas, whereby the unprinted area preferably takes up less than 50% of the width of a printed area.

The shape of the areas can vary; the areas can be designed as geometric shapes, in the form of waves, arrows, bars, stripes, characters, letters, numbers, symbols and the like.

The length of the areas is such that all areas can be viewed from the same viewing angle.

Lengths of about 0.5 to 25 mm have proven to be suitable, for example for areas in the shape of bars.

In a further embodiment, the areas can be printed in the form of a gradient in a defined area so as to overlap, i.e. the transition between the areas is soft and flowing and not along a sharp border.

• 1 , 2, 3 Bereiche mit unterschiedlichen Farbkippeffekten
• 4, 5, 6 farbige Druckschichten, die dem Farbeindruck des zugeordneten Farbkippeffektbereichs unter einem Betrachtungswinkel von 90° entsprechen
• 7 eine elektromagnetische Wellen reflektierende Schicht
• 8 eine polymere oder dielektrische Abstandsschicht mit unterschiedlicher Schichtdicke
• 9 eine Schicht gebildet aus metallischen Clustern oder eine metallische Schicht
• 7 ein Trägersubstrat
• 8 eine Absorptionsschicht zur Verstärkung des Farbkippeffekts
• 9 Aussparungen in der Farbkippeffektschicht
• 10 einen unbedruckten Bereich 11 eine Lackschicht mit einer optisch aktiven Struktur, beispielsweise eine Beugungsstruktur, ein Hologramm oder ein Oberflächenrelief.

In the Figures 1 to 10 exemplary embodiments are shown.

• 1 , 2, 3 areas with different color shift effects
• 4, 5, 6 colored printing layers that correspond to the color impression of the assigned color shift effect area at a viewing angle of 90°
• 7 a layer reflecting electromagnetic waves
• 8 a polymeric or dielectric spacer layer with different layer thickness
• 9 a layer formed from metallic clusters or a metallic layer
• 7 a carrier substrate
• 8 an absorption layer to enhance the colour shift effect
• 9 recesses in the colour shift effect layer
• 10 an unprinted area 11 a lacquer layer with an optically active structure, for example a diffraction structure, a hologram or a surface relief.

In Figure 1 an exemplary embodiment of a security element with three different color shift effects 1, 2, and 3 is shown.

When viewed at an angle of 90°, the target color, in this case a blue color, is only visible in the first area. If the security element is now tilted so that the viewing angle is around 60°, the blue color disappears from the first area and the target color appears in the second area. If the security element is tilted by a further 30°, i.e. so that the viewing angle is 30°, the blue color disappears from the second area and appears in the third area.

The safety element creates the impression of a movement effect of the target color (in this case blue) when tilted.

It is particularly advantageous if, as in this case, not only the color of the areas at a viewing angle of 90° is coordinated in the individual areas, but also the color at the other viewing angles.

If the areas are applied in the form of a gradient, the differences between the individual colors are softened by the color transitions and the movement of the target color tone is not abrupt but fluid.

In Figure 2 The simplest embodiment of the invention is shown.

The security element has two repeating areas , 2 with different color shift effects on a transparent carrier film. In Figure 2a is an embodiment analogous Fig.2 shown, but a further absorption layer 11 is provided below the color shift effect layers 1, 2, 3 to enhance the color shift effect. The absorption layer can be a layer made of an absorbent printing ink, preferably a dark, in particular black, printing ink or else a metallic layer or a layer made of a metal compound, for example of non-stoichiometric aluminum oxide or stoichiometric or non-stoichiometric copper oxide, which was applied, for example, by vapor deposition or sputtering.

In Fig.3 The embodiment is shown, which as in Fig.1 shown, has three different color shift effects 1 , 2, 3, which in this case were applied in an overlapping manner in some areas. The security element shows color gradient zones or a color gradient with overlapping areas 13.

In Figure 4 an embodiment is shown in which the sequence of the different areas 1, 2, 3 is arranged in opposite directions.

In Figure 5 A further preferred embodiment is shown. The areas 1, 2, 3 which have the different color shift effects are not implemented over the entire width of the security element; in the remaining area of the security element, a print layer 4, 5, 6 is applied, the color of which corresponds to the respective color shift effect area when viewed at an angle of 90°.

If the viewing angle is changed, the target color can be seen moving from one area to another in the area of the different color shift effects. No color change occurs in the area of the printing color. The color of the printing area remains unchanged and is then different to the color tone of the color shift effect area. Alternatively, the color of the color shift effect can initially correspond to the color impression of the printing color under any other viewing angle, with the effect described above then occurring analogously when the viewing angle is changed.

In Fig.6 an embodiment is shown in which recesses 12 in the form of numbers or symbols are provided in the color shift effect layer areas 1, 2. These recesses can be made by recesses in the color shift effect printing layer or, if the color shift effect layer is realized by a multilayer structure consisting of an electromagnetic wave reflecting layer, a spacer layer 8 and an absorption layer 9 made of a metallic layer or a layer formed from metallic clusters, by recesses in the electromagnetic wave reflecting layer 7 and/or the absorption layer 9τ

The recesses can be in the form of geometric shapes, characters, letters, numbers, lines or symbols and can be provided in one or more of the areas with different color shift effects. No recess is provided in the color shift effect layer area 3.

In Figure 7 an embodiment is shown in which the areas of different color shift effects 2, 3 are designed in arrow shape.

In Figure 8 An embodiment is shown in which the areas of different color shift effects 1, 2, 3 are designed in a wave shape. In the individual areas, recesses 12 in the form of letters are provided.

In Figure 9 an embodiment is shown in which the areas of different color shift effects 1, 2, 3 are separated from one another by an unprinted area 13. In addition, the carrier substrate has a lacquer layer of an optically active structure, for example a diffraction structure, a hologram, a surface relief or the like, under the layer with the areas of different color shift effects. This lacquer layer can optionally be combined with a reflection layer (not shown), for example a metallic reflective layer, which is not shown in Fig. 10.

In a further embodiment, the security element can also be designed as a transfer material, wherein the security element is then fixed to the object to be secured by means of an adhesive layer and the carrier substrate is then removed if necessary.

In this case, it may be advantageous to provide the carrier substrate with a release layer before applying the security features.

The security element according to the invention can also have further security features, which can be present in further layers. These security features can be located below or above the layer which has the color shift effect according to the invention, whereby care must be taken not to disturb the impression of the moving color shift effect.

Alternatively, the additional security features can also be printed in unprinted areas or instead of at least one of the Fig.5 The pressure ranges 4, 5, 6 shown may be provided.

These security features, for example, can have certain chemical, physical and also optical or optically active properties.

Paramagnetic, diamagnetic and also ferromagnetic substances such as iron, nickel and cobalt or their compounds or salts (e.g. oxides or sulfides) can be used to adjust the magnetic properties of a layer.

Particularly suitable are magnetic pigment paints with pigments based on Fe oxides, iron, nickel, cobalt and their alloys, barium or cobalt ferrites, hard and soft magnetic iron and steel types in aqueous or solvent-based dispersions. Examples of solvents that can be used are i-propanol, ethyl acetate, methyl ethyl ketone, methoxypropanol and mixtures thereof.

Preferably, the pigments are incorporated in acrylate polymer dispersions having a molecular weight of 150,000 to 300,000, in nitrocellulose, acrylate-urethane dispersions, acrylate-styrene or PVC-containing dispersions or in solvent-containing dispersions of this type.

The magnetic layer can also have a coding. Magnetic materials with the same coercivity and/or remanence as well as different coercivity and/or remanence can be used to form the coding.

In a further embodiment, the electromagnetically reflective metallic layer of the color shift effect setup can itself have magnetic properties. This is achieved, for example, by using a magnetic material such as Fe, Ni, Co.

To adjust electrical properties, such as conductivity, graphite, carbon black, conductive organic or inorganic polymers, metal pigments (such as copper, aluminum, silver, gold, iron, chromium and the like), metal alloys such as copper-zinc or copper-aluminum or even amorphous or crystalline ceramic pigments such as ITO and the like can be added. Furthermore, doped or non-doped semiconductors such as silicon, germanium or ion conductors such as amorphous or crystalline metal oxides or metal sulfides can be used as additives. Furthermore, polar or partially polar compounds such as surfactants or non-polar compounds such as silicone additives or hygroscopic or non-hygroscopic salts can be used or added to adjust the electrical properties of the layer.

The optical properties of the layer can be influenced by visible dyes or pigments, heat-sensitive colors or pigments. These can be used individually or in all possible combinations. Optically active features here include diffraction structures, diffraction gratings, kinegrams, holograms, DID ^® (0th order microstructures in combination with thin films).

These optically active features can be created, for example, by known UV embossing processes, such as those used in EP 1 310 381 A described or produced by hot stamping processes.

The optically active features can optionally be combined with a full-surface or partial reflection layer, for example with a metallic reflective layer or an HRI layer (high refractive index layer).

In order to anchor the security element in or on the value document, it is usually provided with an adhesive coating on one or both sides. This adhesive coating can be in the form of a hot-seal, cold-seal or self-adhesive coating. The adhesive can also be pigmented, whereby all known pigments or dyes can be used as pigments, for example T'IO2, ZnS, kaolin, ATO, FTO, aluminum, chromium and silicon oxides or, for example, organic pigments such as phthalocyanine blue, i-indolide yellow, dioxazine violet and the like. Furthermore, luminescent dyes or pigments that fluoresce or phosphoresce in the visible, UV or IR range, heat-sensitive colors or pigments can be added. These can be used in all possible combinations. In addition, luminescent pigments can also be used. used alone or in combination with other dyes and/or pigments.

If necessary, the security element can also be protected by one or more protective lacquer layers, which can be pigmented or unpigmented, or can be further refined, for example, by laminating or the like. If necessary, the security element can also be provided with an adhesive layer on one or both sides, for example with a cold or hot sealing layer or a self-adhesive coating.

The security elements according to the invention are therefore suitable, if appropriate after appropriate packaging, as security features in data carriers, in particular value documents such as identity cards, cards, banknotes or labels, seals and the like, but also as packaging material, for example in the pharmaceutical, electronics and/or food industries, for example in the form of blister films, folding boxes, covers, film packaging and the like.

For use as security features, the substrates or security elements are preferably cut into strips or threads or patches, whereby the width of the strips or threads can preferably be 0.05 - 10 mm and the patches preferably have average widths or lengths of 0.3 - 20 mm.

For use in or on packaging, the security element is preferably cut into strips, tapes, threads or patches, the width of the threads, strips or tapes preferably being 0.05 - 50 mm and the patches preferably having average widths and lengths of 2 - 30 mm.

Claims (11)

1. A security element for banknotes, value documents and data carriers, comprising a carrier substrate (7) and a coating which has color-shifting effects, wherein the coating has repeating regions (1, 2, 3) with different color-shifting effects, wherein the regions are in each case matched to one another in such a way that when the viewing angle is continuously changed, the original color of a first region first becomes visible in a region adjacent to this first region or in a region spaced apart from this first region or in a region at least partially overlapping this first region and, when the viewing angle is further changed, becomes visible in respectively further adjacent, spaced apart or overlapping regions, characterized in that

   the regions of different color-shifting effects (1, 2, 3) are formed by a printed layer of color-shifting effect printing ink or

   are formed in each case by a coating consisting of a layer reflecting electromagnetic waves, a spacer layer and an absorber layer.
2. The security element according to claim 1, characterized in that the regions of different color-shifting effects (1, 2, 3) are configured as geometric shapes or in the form of waves, arrows, bars, strips, characters, letters, numbers, symbols.
3. The security element according to claim 1 or 2, characterized in that the coating having different color-shifting effects (1, 2, 3) is not formed over the entire width of the security element.
4. The security element according to claim 3, characterized in that the security element, in the region that is not provided with the coating having different color-shifting effects, has a printed layer that in each case corresponds in terms of color to that of the region with the color-shifting effect when viewed at an angle of 90°.
5. The security element according to one of claims 1 to 4, characterized in that the sequence of the regions with different color-shifting effects is in opposite directions over the length of the security element.
6. The security element according to one of claims 1 to 5, characterized in that an absorption layer is provided under the coatings with different color-shifting effects to reinforce the color-shifting effect.
7. The security element according to one of claims 1 to 6, characterized in that recesses (9) in the form of geometric shapes, characters, letters, numbers, lines or symbols are provided in one or more of the regions with different color-shifting effects.
8. The security element according to one of claims 1 to 7, characterized in that it is provided with a protective lacquer coating on one or both sides.
9. The security element according to one of claims 1 to 8, characterized in that it is provided with an adhesive coating on one or both sides.
10. The security element according to one of claims 1 to 9, characterized in that it is configured as a transfer element.
11. A use of the security element according to one of claims 1 to 10 for embedding in and/or for application on value documents, data carriers or packaging.

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