Optically variable security element, method of manufacture and stamping assembly

Abstract

The invention relates to an optically variable security element (20) for providing security for value documents. The security element has a feature layer (24) which comprises a first and a second feature area (30, 40) which are arranged in register with one another in a common plane. The first feature area (30) comprises a first intaglio lacquer layer made of a first intaglio lacquer (32), into which intaglio structures (34) are embossed which produce a first optical effect. The second feature area (40) comprises a second intaglio lacquer layer made of a second intaglio lacquer (42), into which intaglio structures (44) are embossed which produce a second, different optical effect. Here, the first and the second intaglio lacquer (32, 42) have both different curing properties and different optical properties. The invention also relates to a production method for such an optically variable security element as well as an intaglio assembly with a security element semi-finished product and a device for embossing intaglio structures.

Description

[0001] The invention relates to an optically variable security element for providing security for value documents and to a manufacturing method for such an optically variable security element. The invention further relates to an embossing assembly with a security element semi-finished product and a device for embossing an embossing structure.

[0002] Data carriers such as value documents or identity documents or other value documents such as luxury goods are often equipped with security elements for security purposes, which can verify the authenticity of the data carrier and at the same time serve as protection against unauthorized copying. The security elements can be designed, for example, as security threads embedded in banknotes, cover films for banknotes with holes, applied security strips, self-supporting transfer elements or also as feature areas printed directly on the value document.

[0003] At an earlier point in time, optically variable security elements were proposed which have two relief structures arranged at different height levels and each equipped with a color coating, which are embossed in a matching dyed embossing lacquer layer, see WO 2020 / 011390 A1, WO 2020 / 011391 A1 and WO 2020 / 011392 A1. However, in order to observe the lower relief structure, the observer here usually has to look through the embossing lacquer layer of the higher relief structure, so that the coloring of the embossing lacquer, in particular of the higher embossing lacquer layer, can form a greater restriction depending on the desired optical impression.

[0004] Starting from this, the technical problem addressed by the invention is to provide an optically variable security element of the type described at the outset with an attractive appearance and a high security against forgery and an advantageous manufacturing method for such an optically variable security element.

[0005] The technical problem is solved by the technical solution described below.

[0006] The invention provides an optically variable security element for providing security for value documents, having a feature layer which comprises a first and a second feature area arranged in register with one another in a common plane, wherein the first feature area comprises a first embossing lacquer layer made of a first embossing lacquer, in which embossing structures producing a first optical effect are embossed, and the second feature area comprises a second embossing lacquer layer made of a second embossing lacquer, in which embossing structures producing a different second optical effect are embossed, and the first and second embossing lacquers have both different curing properties and different optical properties.

[0007] To solve the stated technical problem, the present application comprises an optically variable security element, which can be used, inter alia, for providing security for value documents. The security element is provided with a feature layer, which comprises a first and a second feature area arranged in register with one another in a common plane.

[0008] The register arrangement of the feature areas here denotes, inter alia, an arrangement in which the first and the second feature area abut one another or are arranged at a predetermined, defined small distance from one another. The small distance is, inter alia, a distance of a few micrometers or tens of micrometers and not more than 100 pm and in some applications not more than 200 pm.

[0009] The first feature area comprises a first embossing lacquer layer made of a first embossing lacquer, into which embossed structures producing a first optical effect are embossed. The second feature area comprises a second embossing lacquer layer made of a second embossing lacquer, into which embossed structures producing a different second optical effect are embossed.

[0010] Here, the first and the second embossing lacquer have both different curing properties and different optical properties.

[0011] The different curing properties of the embossing lacquers can lie in different curing methods, which respectively effect the curing of the lacquer, i.e. inter alia for thermoplastic embossing lacquers physical drying or for radiation-hardening embossing lacquers radiation hardening. The different curing properties can also lie in different curing parameters in the same curing method, i.e. for example for thermoplastic embossing lacquers in different softening temperatures or for radiation-hardening embossing lacquers in different radiation types, radiation intensities or irradiation times. Radiation-hardening embossing lacquers comprise, inter alia, UV-hardening, IR radiation-hardening and electron beam-hardening embossing lacquers.

[0012] In a preferred design, the first and the second embossing lacquer are respectively formed by thermoplastic embossing lacquers having different softening temperatures, so that the embossing lacquers have different curing properties due to the different curing parameter "temperature". The difference in the softening temperatures is preferably greater than 10°C, preferably greater than 25°C, in particular greater than 50°C.

[0013] According to a further equally advantageous design, the first embossing lacquer is formed by a radiation-hardening embossing lacquer, in particular a UV-hardening embossing lacquer, and the second embossing lacquer is formed by a thermoplastic embossing lacquer. Thus, the first embossing lacquer can be hardened by radiation, while the second embossing lacquer can be embossed in an elevated temperature and cured on cooling, so that different curing methods effect the curing of the lacquer.

[0014] As different optical properties, the first and second embossing lacquer can in particular have different colors, different transparencies and / or different luminous properties. Here, the embossing lacquer is advantageously tinted with a gloss and is thus both colored and partially transparent.

[0015] The UV embossing lacquers and thermoplastic embossing lacquers (also referred to as thermoplastics) used generally have the properties described below, however, for particular applications, lacquers with different properties can also be used.

[0016] The usual UV embossing lacquers are first of all significantly more easily embossable than thermoplastic embossing lacquers. For UV embossing, for example, the embossing lacquer in liquid form can first be applied to the film. This can be achieved without the roller contact of the embossing mold. The film with the embossing lacquer is brought into contact with the embossing mold by means of a top roller, wherein the lacquer surface forms the structure of the embossing mold. In a theoretically infinitely slow process, without pressure, the lacquer simply flows into the structure and expels the air. In practice, however, the embossing process on the machine is not infinitely slow, so that at the time of embossing the lacquer is no longer able to expel the air completely in the preset time due to the too small pressing pressure. Thus, in practice, a certain embossing pressure is worked with if there are certain requirements on speed and bubble freedom. If no UV hardening is achieved, the lacquer flows again immediately after the film has been removed from the embossing mold after the contact with the embossing mold. In practice, however, the film has a certain wrapping on the embossing mold. If the film with the lacquer is brought into contact with the embossing mold by means of a top roller, the film generally no longer spontaneously moves away from the embossing mold. Downstream of the top roller, in a region which is otherwise pressureless, a UV radiator is arranged which crosslinks the UV lacquer during the time when the UV lacquer is still in contact with the embossing mold. The film is only removed from the embossing mold after this reaction. The entire process is generally run continuously. The lacquer thus solidified is generally a thermoset plastic.

[0017] Thermoplastic embossing is generally achieved differently from the described UV embossing. Thermoplastics are in solid form at room temperature and are accordingly not flowable, at increased temperatures the thermoplastics can be embossed at a certain temperature. At further increased temperatures the lacquer becomes sticky, thus limiting the useful embossability by standard embossing molds. However, if necessary, molds with a non-sticky coating can be used. In thermoplastic embossing, for example, the embossing punch can be heated, embossed at increased temperature and, if necessary, slightly cooled before demolding. In a roll-to-roll process, cooling is generally not achieved before demolding. Here, in the case of thermoplastic embossing, the film can for example be heated, if necessary, in contact with the embossing mold and embossed at the highest temperature and immediately demolded without reaching the sticky region of the thermoplastic. Heating up to the point at which the thermoplastic really becomes liquid is advantageously avoided.

[0018] In order to avoid the adhesion or rather the sticking of thermoplasts with a lower melting point, the embossing die advantageously is provided with a non-stick coating. Alternatively it can be provided that the unembossed embossing lacquer is metallized for avoiding the sticking or for ensuring that a thermoplastic with a higher melting point only becomes molten at a later point in time. This can be ensured, for example, by means of the crosslinking agents mentioned elsewhere (e.g. isocyanates) or also by radiation crosslinking. For example, two UV raw materials which can be embossed thermoplastically can be provided side by side, wherein one of the two formulations contains a photoinitiator. After the first embossing, an exposure can be carried out, in which case the demolding can be carried out later, since the lacquer in the solid state obtains the embossed structure even without contact with the embossing die. The melting point of the formulation containing the photoinitiator is thereby raised and can no longer be deformed under the previous embossing conditions. The second embossing can then be carried out. The second "thermoplastic" either is not crosslinked or is postcrosslinked by electron beam hardening, since the latter process can be carried out without the use of a photoinitiator. Alternatively, the second thermoplastic can also contain a photoinitiator, which does not react in the wavelength of the first radiation.

[0019] In addition to the already mentioned advantageous designs of the embossing lacquer, it is in principle also possible to use embossing lacquers which are hardened or crosslinked thermally instead of photochemically. For example, some embossing lacquers have a softening temperature T1 and a hardening temperature T2 > T1. Such embossing lacquers can be formed, for example, on the basis of acrylates with isocyanates.

[0020] Another method is to selectively heat one of the embossing lacquers. Here, regions with selectively excitable substances (excited in UV / visible / IR or electrically / capacitively / magnetically by an alternating field) selectively only cause the regions containing such substances to be heated. In this way, for example, two regions with UV embossing lacquer can also be provided and the regions are processed, in particular embossed, in succession.

[0021] It is advantageous if the embossed structures of the first and second embossing lacquer layer respectively contain structure elements with a structure size of between 30 μm and 200 μm, in particular between 50 μm and 150 μm, in said plane. One or both embossed structures advantageously contain as structure elements micromirror assemblies with directed reflecting mirrors, in particular with mirrors which do not diffract, and preferably with plane mirrors, concave mirrors and / or Fresnel mirrors.

[0022] The imprinted structures of the first and second imprinting layers can advantageously be directly connected to each other; however, it is also possible for a narrow transition region to exist between the imprinted structures of the first and second imprinting layers, in which the imprinting height and / or imprinting quality of one of the imprinted structures decreases. The transition region preferably has a width of less than 10 μm, particularly less than 5 μm. In the transition region, the shape of the imprinted structure can, for example, remain unchanged, but the height of the imprinted structure can decrease from a maximum value inside the feature region to a minimum value at the edge of the feature region adjacent to it. This minimum value can also be zero. In the transition region, the quality of the imprinted structure may also decrease compared to the interior of the feature region; for example, the structural elements of the imprinted portion may only be incompletely transferred to the imprinting enamel.

[0023] The embossed paint layers of the first and second feature regions are advantageously arranged side by side without gaps or overlaps.

[0024] The embossed structures of the first and second embossed enamel layers are advantageously located at substantially the same height, which in particular means that the difference in the average height of the two embossed structures does not exceed the height difference within each embossed structure.

[0025] In an advantageous extended design, the first and second embossed paint layers are provided with a common reflective coating, particularly a high-refractive or metallic coating.

[0026] According to an advantageous design, the anti-counterfeiting element has a carrier film that is easily deformable, particularly a carrier film with a thickness of less than 23 μm, preferably less than 19 μm, and especially preferably between 6 μm and 15 μm. As an easily deformable carrier film, a carrier film with a glass transition temperature Tg lower than the softening temperature of at least one thermoplastic embossing varnish of the feature layer is also advantageously considered.

[0027] According to another advantageous design, the anti-counterfeiting element includes a compensation layer that is flexible, especially elastic, at the softening temperature of at least one thermoplastic embossing varnish of the feature layer, i.e., capable of reversible deformation.

[0028] For example, the compensation layer can be formed of silicone rubber. Depending on the characteristics of the compensation layer, it may be advantageous to use it as an intermediate layer in a sandwich structure having a carrier film, a compensation layer, and a thin capping layer to ensure problem-free coatability through the final capping layer. The thin capping layer advantageously has a thickness of 3 to 6 μm, for example, 4.5 μm. The thickness of the compensation layer advantageously is between about 2 and about 20 μm.

[0029] The compensation layer can also be formed of or contain foam. Such compensation layers formed of or containing foam are particularly flexible and compressible, but often exhibit light scattering at the bubble boundaries and therefore generally have low transparency.

[0030] It goes without saying that optically variable anti-counterfeiting elements may include other layers, such as protective layers, overlays, or additional functional layers, machine-readable elements, primer layers, or heat-sealing coatings; however, these layers do not constitute the essential elements of this invention and are therefore not described in detail.

[0031] Anti-counterfeiting elements are advantageously anti-counterfeiting lines, especially window-type or swing-type anti-counterfeiting lines, tear lines, anti-counterfeiting tapes, anti-counterfeiting strips, patches or labels, which are applied to anti-counterfeiting paper, valuable documents or similar articles.

[0032] The present invention also includes a method for manufacturing an optically variable anti-counterfeiting element, wherein a feature layer is generated on a carrier, the feature layer comprising first and second feature regions arranged in a common plane and aligned with each other.

[0033] In the method, a first imprinting varnish layer made of a first imprinting varnish is applied to a first feature region and an imprinting structure that produces a first optical effect is imprinted onto the imprinting varnish layer.

[0034] A second embossing layer made of a second embossing varnish is applied to the second feature region, and a second embossing structure that produces a different second optical effect is embossed onto the embossing varnish layer.

[0035] Here, the following printing inks are applied as first and second printing inks, respectively, having different optical properties and different curing properties, and / or curing at different times. Currently, it is preferred to use printing inks with different curing properties, but if the printing inks cure at different times, printing inks with the same curing properties can also be used. For example, UV printing inks can be used as the first and second printing inks, respectively, and the first UV printing ink can be cured after UV printing before the second UV printing ink is applied, and the second UV printing ink can also be cured after UV printing. In this case, the printing inks cure at different times, but otherwise can have the same curing properties.

[0036] The advantageous method variant specifies that,

[0037] - A first imprinting layer made of a thermoplastic imprinting paint with a high softening temperature is applied to a first feature region, and a second imprinting layer made of a thermoplastic imprinting paint with a low softening temperature is applied to a second feature region.

[0038] - The first imprinting step is performed at a higher temperature, and a first imprinting structure is provided for the first imprinted paint layer.

[0039] - Next, a second imprinting step is performed at a lower temperature, and a second imprinting structure is configured for the second imprinting paint layer.

[0040] In other equally advantageous method variations, it is specified that...

[0041] - A first embossing layer made of thermoplastic embossing varnish is applied to a first feature region, and a second embossing layer made of radiation-cured embossing varnish is applied to a second feature region.

[0042] - The first imprinting step is performed at a higher temperature, and a first imprinting structure is provided for the first imprinted paint layer.

[0043] Next, a second imprinting step is performed at a lower temperature and under radiation, where a second imprinting structure is provided for the second imprinting paint layer, and the second imprinting paint layer is hardened.

[0044] In all variations of the method, in the first imprinting step, the first imprinting layer is imprinted and cured, while the second imprinting layer remains deformable and partially or completely flows after the first imprinting step.

[0045] Another advantageous method variant specifies that,

[0046] - A first embossing layer made of radiation-cured embossing varnish is applied to the first feature region, and a second embossing layer made of thermoplastic embossing varnish is applied to the second feature region.

[0047] - In the first imprinting step, a first imprinting structure is provided for the radiation-cured imprinting enamel, and the radiation-cured imprinting enamel is cured, and

[0048] - Next, the second imprinting step is performed, and a second imprinting structure is configured for the second imprinting paint layer.

[0049] Here, in the second imprinting step, the second imprinting structure is only transferred to the second imprinting enamel layer, but not to the first imprinting enamel layer.

[0050] A particular advantage is that, in the second imprinting step, a flexible imprinting die, a soft imprinting top roller, or a flexible compensation layer in the layered structure of the anti-counterfeiting element is used to transfer the second imprinting structure only into the second imprinting layer. This ensures that the imprinted portion in the second feature region is transferred into the second imprinting layer without damaging or destroying the existing first imprinting structure. As explained in detail below, for this purpose, the flexible imprinting die can deform within the area of ​​the hardened first imprinting structure, or the area with the hardened first imprinting structure can be sufficiently pressed into the soft imprinting top roller or the flexible compensation layer.

[0051] The present invention also includes an embossing assembly comprising:

[0052] - A semi-finished anti-counterfeiting element, for further processing into an optically variable anti-counterfeiting element of the type described above, the semi-finished anti-counterfeiting element having a feature layer comprising first and second feature regions arranged in a common plane and aligned with each other, wherein,

[0053] -- The first feature region comprises an imprinting enamel layer made of cured imprinting enamel, and an imprinted structure that produces the first optical effect is imprinted into the imprinting enamel layer, and

[0054] -- The second feature region contains a second embossing layer made of uncured embossing varnish.

[0055] -- Among them, the first and second imprinting paints have different curing properties and different optical properties, and

[0056] - A flexible embossing mold having a second embossing structure is preferably used to emboss the embossing structure that produces different second optical effects only onto the embossing paint layer with uncured embossing paint of the anti-counterfeiting element semi-finished product.

[0057] In this regard, flexible embossing molds can be made of silicone rubber.

[0058] Finally, the present invention also includes an imprinting assembly comprising:

[0059] - A semi-finished anti-counterfeiting element, for further processing into an optically variable anti-counterfeiting element of the type described above, the semi-finished anti-counterfeiting element having a feature layer comprising first and second feature regions arranged in a common plane and aligned with each other, wherein,

[0060] -- The first feature region comprises an imprinting enamel layer made of cured imprinting enamel, and an imprinted structure that produces the first optical effect is imprinted into the imprinting enamel layer, and

[0061] -- The second feature region contains a second embossing layer made of uncured embossing varnish.

[0062] -- Among them, the first and second imprinting paints have different curing properties and different optical properties, and

[0063] - A hard embossing die with a second embossing structure and a soft embossing top roller with a Shore hardness of less than 90, especially less than 85, are preferably used to emboss the embossing structure that produces different second optical effects only into an embossing paint layer with uncured embossing paint, by embossing the anti-counterfeiting element semi-finished product between the hard embossing die and the soft embossing top roller.

[0064] Other embodiments and advantages of the present invention are described below with reference to the accompanying drawings. For the sake of clarity, the views in these drawings are not presented to scale.

[0065] In the attached diagram:

[0066] Figure 1 A schematic diagram of a banknote with optically variable security features is shown.

[0067] Figure 2 A schematic diagram illustrates an anti-counterfeiting element having a carrier substrate, the carrier substrate having an embossed feature layer.

[0068] Figure 3 Four intermediate steps in manufacturing a security element with a feature layer using thermoplastic embossing paint with two different softening temperatures are shown in (a) to (d).

[0069] Figure 4 Four intermediate steps in manufacturing anti-counterfeiting elements with feature layers from thermoplastic embossing paint and UV embossing paint are shown in (a) to (d).

[0070] Figure 5 Intermediate steps in manufacturing anti-counterfeiting elements using flexible embossing molds are shown in (a) to (c).

[0071] Figure 6 (a) through (c) show intermediate steps in the manufacture of anti-counterfeiting elements using a combination of a hard embossing die and a soft embossing top roller.

[0072] Figure 7 (a) through (c) show intermediate steps in the manufacture of the anti-counterfeiting element, in which a flexible compensation layer is provided in the layered structure of the anti-counterfeiting element.

[0073] Figure 8 (a) through (d) illustrate intermediate steps in applying two different imprinting inks to a feature layer, wherein the imprinting inks do not exhibit registration ripples.

[0074] Figure 9(a) through (c) show intermediate steps in other variations of applying two different imprinting inks to a feature layer, wherein the imprinting inks do not have registration ripples.

[0075] Figure 10 (a) through (c) show an intermediate step in another variation of applying two different imprinting inks to a feature layer, wherein the imprinting inks do not have registration ripples.

[0076] Figure 11 Intermediate steps in applying and structuring UV imprinted coatings at high resolution are shown in (a) and (b).

[0077] Figure 12 Intermediate steps for applying two different imprinting inks to the feature layer without registration fluctuations are shown in (a) and (b).

[0078] Figure 13 Intermediate steps in a method for applying two different imprinting inks in alignment by mechanical layer removal are shown in (a) through (c), and

[0079] Figure 14 Intermediate steps in a method for applying two different imprinting inks in alignment by selectively removing the medium are shown in (a) through (d).

[0080] The invention will now be described using an anti-counterfeiting element for banknotes as an example. Therefore, Figure 1 A schematic diagram of a banknote 10 is shown, which has an optically variable security element 12 in the form of an adhesive transfer element. However, it is self-evident that the invention is not limited to transfer elements and banknotes, but can be used for all types of security elements, such as labels on goods and packaging, or for providing security for documents, certificates, passports, credit cards, health cards, or similar items. For banknotes and similar documents, in addition to transfer elements (such as patches with or without their own carrier layer), security threads or security strips can also be considered, for example.

[0081] Although the anti-counterfeiting element has a planar design, the anti-counterfeiting element 12 gives the observer a three-dimensional impression and simultaneously displays a binary color and effect change, for example, when the banknote 10 is tilted, wherein the three-dimensional visual object is viewed from a first viewing direction and is displayed in a first color and in a second viewing direction.

[0082] Such and numerous other visual effects can be advantageously produced by anti-counterfeiting elements in which two or more embossed paint layers are aligned side-by-side in a plane of the anti-counterfeiting element, each embossed paint layer being specifically equipped with different, independent embossing structures. In addition to the different embossing portions, the embossed paint layers also suitably possess other different characteristics, namely, particularly different visual characteristics, such as different colors, transparency, and / or luminescence. In this way, the optically variable effects produced by the embossing portions and the visual effects produced by the additional characteristics of the embossed paint layers can be perfectly aligned and matched.

[0083] To illustrate, Figure 2 The schematic diagram shows an anti-counterfeiting element 20, which has a carrier film 22 in the form of a transparent PET film, on which an embossed feature layer 24 is disposed. The feature layer 24 consists of an alternating sequence of feature regions 30, 40 having desired shapes and sizes (only one of these feature regions is respectively labeled), which are different from each other due to the different varnishing colors of the applied embossing paint layers 32, 42 and the different designs of the corresponding embossing structures 34, 44.

[0084] The embossed structures 34 and 44 of the two feature regions 30 and 40 are substantially at the same height in a common plane and are provided with a common reflective metal coating 26, such as a vapor-deposited aluminum layer. In this embodiment, the metallized embossed structure is leveled with a paint layer 28, and the anti-counterfeiting element can be adhered to the desired target substrate, such as banknote 10, via an adhesive layer 29. After adhesion, the carrier substrate 22 can be peeled off or retained in the anti-counterfeiting element as a protective film.

[0085] The anti-counterfeiting element 20 is designed to be observed through the varnished embossed paint layers 32 and 42. Here, the observer 14 looks through the embossed paint layer region 32 into the feature region 30 towards the metallized embossed structure 34, and in the feature region 40, looks through the embossed paint layer region 42 into the metallized embossed structure 44. For example, the embossed paint 32 can be varnished red and the embossed structure 34 can produce an arched view of the number "10" as a visual object, while the embossed paint 42 can be varnished green and the embossed structure 44 can produce an arched view of a badge as a visual object. These two visual objects can also be identifiable from different viewing directions. For example, from... Figure 2 As can be seen, the feature regions 30 and 40 are arranged side by side and aligned with each other, with the different color effects produced by the embossing paint layers 32 and 42 and the different visual objects produced by the embossing parts 34 and 44, without gaps or overlaps.

[0086] Now for reference Figure 3 and Figure 4The basic principles of the advantageous manufacturing of, for example, the feature layer 24 of the anti-counterfeiting element 20 will be explained in more detail. Figure 3 and Figure 4 Four intermediate steps in the manufacture of the anti-counterfeiting element 20 are shown in (a) to (d).

[0087] First, refer to Figure 3 (a) A carrier film 22, such as a transparent colorless PET film, is provided, and the desired feature areas 30 and 40 are coated with a thermoplastic embossing paint 32 or 42, respectively, having the desired color effect. Here, the thermoplastic embossing paints 32 and 42 are adapted to each other such that, in addition to their different colors, they also have different softening temperatures, thus allowing them to be embossed at different temperatures. For example, thermoplastic embossing paint 42 can be embossed at a lower temperature T2, while thermoplastic embossing paint 32 can only be embossed at a higher temperature T1>T2.

[0088] Subsequently, in the first imprinting step, the first imprinting mold 50 is used to equip the two imprinting paints 32 and 42 with the first imprinting structure 34. The first imprinting step is carried out at a relatively high temperature T1, such as... Figure 3 As shown in (b).

[0089] Then, the carrier film with the imprinted feature layer is cooled to a lower temperature T2 and demolded, thereby solidifying the imprinting varnish 32 in the feature region 30 with the pressed imprinted structure 34, while the imprinting varnish 42 remains deformable. Therefore, the imprinting varnish 42 will still partially or completely flow after demolding, and at most can only incompletely form or receive the first imprinted portion, as in... Figure 3 As shown by reference numeral 34' in (c).

[0090] exist Figure 3 (c) also shows a second embossing die 52 for the second embossing step, through which the second embossed structure 44 is embossed at a lower temperature T2 into the still deformable embossed varnish layer 42 of the feature region 40. The embossed structure 34 of the feature region 30 has been cured, and the embossed structure is no longer significantly affected by the second embossing step, especially due to the measures described in detail below.

[0091] After the second imprinting step, the carrier film with the feature layers of the two imprints is cooled to a temperature T < T2, for example, to room temperature, and the imprinting paint 42 in the feature region 40 is thus cured.

[0092] Feature layer 24 is obtained in this manner, which has desired double imprinted portions 34 and 44 registered with feature regions 30 and 40, such as Figure 3 As shown in (d). Subsequently, feature layer 24 can be metallized, as follows: Figure 2 As shown, orFigure 3 (d)'s intermediate product can be further processed in other ways into the desired anti-counterfeiting element.

[0093] In Figure 4 's design, instead of using two thermoplastic imprinting varnishes with different softening temperatures, one thermoplastic imprinting varnish 32 and one UV imprinting varnish 42 are used. Different from the design described below, in Figure 4 's design, the thermoplastic imprinting varnish is imprinted first, and then the UV imprinting varnish is imprinted. Although the UV imprinting varnish is generally easier to imprint than the thermoplastic imprinting varnish, with the use of a suitable imprinting varnish and / or under suitable conditions, an imprinting sequence such as Figure 4 can also be used.

[0094] Referring to Figure 4 (a), a carrier film 22, such as a transparent colorless PET film, is provided and coated in the feature area 30 with a thermoplastic imprinting varnish 32 and in the feature area 40 with a UV imprinting varnish 42, respectively, with desired different color effects.

[0095] Then, in the first imprinting step, under the imprinting conditions where the thermoplastic imprinting varnish 32 is imprintable, the first imprinting structure 34 is pressed in through the first imprinting die 50, as shown in Figure 4 (b). The imprinting conditions can include, for example, a temperature T1 of 120 °C and a high imprinting pressure.

[0096] Immediately, the carrier film with the imprinted feature layer is cooled to a lower temperature T2 < T1 and demolded, thereby curing the imprinting varnish 32 in the feature area 30. The lower temperature T2 can be, for example, T2 = 30 °C. Under the imprinting conditions of the first imprinting step, the UV imprinting varnish 42 is not imprinted. Therefore, after the first imprinting step, there is an imprinting varnish 32 provided with an imprinting structure 34 in the feature area 30, and an unimprinted UV imprinting varnish 42 in the feature area 40, as shown in Figure 4 (c).

[0097] In Figure 4 (c), a second imprinting die 52 is also shown. Through the second imprinting die, the second imprinting structure 44 is imprinted into the UV (ultraviolet) curable imprinting varnish layer 42 in the feature area 40 at the lower temperature T2 and under UV irradiation 54. By hardening the imprinting varnish layer 42 by means of radiation from a UV-LED, the heat input into the thermoplastic layer 32 can be minimized. Due to the lower temperature in the second imprinting step and due to the measures described in detail below, the already cured imprinting structure 34 in the feature area 30 is not significantly affected by the second imprinting step.

[0098] After the second imprinting step and UV curing, the imprinting paint 42 in the feature area 40 is also cured, therefore, as in Figure 3 In this manner, feature layer 24 is obtained, wherein the feature layer has desired double imprinted portions 34, 44 aligned with feature regions 30, 40, such as... Figure 4 As shown in (d).

[0099] In Figure 3 and Figure 4 In the design scheme described in relation to this, both imprinting layers 32 and 42 are already present on the carrier film in the first imprinting step. However, it is also possible to apply the layer to be imprinted later only after the layer to be imprinted first has been imprinted. In this case, it is also important that the imprinted portion of the layer imprinted first remains unchanged under the imprinting conditions of the layer imprinted later. Special measures are usually required for this, which are now referred to... Figures 5 to 7 To elaborate further.

[0100] One possibility to ensure that the embossed portion of the first embossed layer is not damaged or destroyed by subsequent embossing steps is to use a flexible embossing die for the second embossing.

[0101] according to Figure 5 The design scheme illustrates this point, in which feature layer 24 and Figure 4 The example similarly includes a feature region 30 with thermoplastic embossing varnish 32 on one side and a feature region 40 with UV embossing varnish 42 on the other side. The structures 34 or 44 to be embossed respectively have structural dimensions L1 or L2 of 50 μm to 150 μm in the plane. The structural height is typically on the order of a few micrometers.

[0102] exist Figure 5 In the modified scheme, the desired second imprinting structure 44 is first provided for the UV imprinting enamel 42, and then the UV imprinting enamel is cured, such as... Figure 5 As shown in (a). Thermoplastic embossing paint 32 can also be embossed, or as shown in (a). Figure 5 As shown in (a), thermoplastic embossing paint can maintain an unpressed structure due to flow.

[0103] Now, a first imprinted structure 34 is imprinted using a flexible imprinting die 60, the die having the desired imprinted structure 34 on its surface. The flexible imprinting die 60 is formed, for example, of silicone rubber and deforms over a length scale λ of several micrometers by a pressure tip. The characteristic region 40 with the already hardened UV imprinting varnish 42 causes a corresponding deformation 62 of the flexible imprinting die 60 during imprinting; thus, on the one hand, the hardened imprinting varnish region 42 is not damaged, but on the other hand, the imprinting varnish 32 in the characteristic region 30 can be imprinted with the imprinted structure 34, such as... Figure 5 As shown in (b).

[0104] Since the transition region 64, where the shape of the embossing die 60 changes drastically, has a size on the order of λ≪L1, L2, meaning that the transition region 64 is significantly smaller than the structural size of the embossing parts 34, 44, the potentially smaller, defective, or even missing embossing parts in the transition region 64 do not have a significant overall impact on the quality of the embossing structure 34 in the feature region 30.

[0105] Therefore, after the thermoplastic embossing paint 32 cools and the flexible embossing mold 60 is demolded, as... Figure 5 As shown in (c), the feature layer 24 is provided with double imprinted portions 34 and 44 with desired registration in the feature regions 30 and 40.

[0106] refer to Figure 6 Another possibility is to use a hard embossing die 70 in conjunction with a soft embossing top roller 72 and a suitable carrier film 74 in the anti-counterfeiting element.

[0107] In this design, Figure 6 The original situation shown in (a) is largely consistent with... Figure 5 Corresponding to the original situation in (a), the feature layer 24 exists on a suitable carrier film 74 as described in detail below, in which a thermoplastic imprinting varnish 32 is applied in the feature region 30 and a UV imprinting varnish 42 is applied in the feature region 40. Here, the desired imprinting portion 44 has already been provided for the UV imprinting varnish 42 in the first imprinting step. Here, the structures 34, 44 to be imprinted also have a structural dimension L1 or L2 between 50 μm and 150 μm in the plane.

[0108] In order to imprint the imprint structure 34 in the second imprinting step, Figure 6 The method uses a hard embossing die 70, which may be made of, for example, nickel. The hard embossing die 70 is particularly suitable for embossing thermoplastic paint 32, but... Figure 6 Compared to the flexible embossing mold 60, the hard embossing mold has a poorer ability to compensate for height differences.

[0109] To ensure that the already imprinted and hardened paint area 42 does not deform or become damaged during the second imprinting step, the fact that imprinting always requires a counter-pressure is utilized; this counter-pressure is typically applied by the imprinting top roller 72. As a unique feature, in Figure 6 The method uses a relatively soft imprinting top roller 72, which is composed of an elastomer with a hardness of less than 90 Shores, especially less than 85 Shores.

[0110] As in Figure 6As schematically shown in (b), in the second imprinting step, the hardened UV imprinting paint area 42 and the carrier film 74 are pressed together by the hard imprinting die 70 far enough into the soft imprinting top roller 72 so that the thermoplastic imprinting paint 32 can be imprinted without damaging or destroying the UV imprinting paint area 42.

[0111] After the thermoplastic embossing paint 32 cools and is demolded, the feature layer 24 thereby provides desired, aligned double embossed portions 34, 44 in the feature regions 30, 40, such as... Figure 7 As shown in (c).

[0112] As an alternative or supplement to using a soft impression top roller 72, the top roller can also be equipped with a structured surface that locally restricts the deformation of the top roller. For example, the surface can be divided into independent honeycombs with a characteristic size of λc≈25μm. Therefore, for example, when the structural sizes of the impression structures 34 and 44 are L1 and L2=100μm, it can be expected that multiple, especially nine, honeycomb segments can exert their ideal impression pressure, while adjacent segments deform strongly.

[0113] Returning to the advantageous characteristics of the carrier film 74, the carrier film must be sufficiently easily deformable under the imprinting conditions of the second imprinting step to allow for movement by the imprinting top roller 72. Figure 7 (b) shows the height compensation.

[0114] For this purpose, a very thin carrier film 74 can be used, preferably less than 23 μm, especially less than 19 μm, and particularly preferably between 6 μm and 15 μm. Alternatively or additionally, the carrier film 74 can also be adapted to the imprinting conditions in such a way that the glass transition temperature Tg of the carrier film is exceeded under the imprinting conditions of the second imprinting step, and the film thus becomes particularly easy to deform.

[0115] Another possibility for ensuring that the first imprinted layer is not damaged or destroyed under the imprinting conditions of the later imprinted layer is to provide a compensation layer 80 in the layer structure of the anti-counterfeiting element itself.

[0116] In order to illustrate, Figure 6 The layer structure of the anti-counterfeiting element to be manufactured is shown, wherein a compensation layer 80 is provided between the carrier film 22 and the feature layer 24. This compensation layer 80 is flexible, at least under the embossing conditions of the second embossing, and preferably has elastic properties. If it is specified that the optical effect of the anti-counterfeiting element is to be observed from the side of the embossed paint layers 32, 42, and therefore also through the compensation layer, the compensation layer is preferably transparent and designed to have low scattering effects. The compensation layer 80 can be specifically formed of silicone rubber, for example.

[0117] existFigure 7 The original case shown in (a) largely corresponds to Figure 7 In the original case of (a), in particular, feature layer 24 contains thermoplastic embossing paint 32 in feature region 30 and UV embossing paint 42 in feature region 40, and the desired embossing portion 44 has been provided for the UV embossing paint in the first embossing step.

[0118] The embossed structure 34 can then be embossed using a hard embossing die 70 in the second embossing step. This hard embossing die is particularly suitable for embossing thermoplastic paint 32. (See reference) Figure 8 As shown in view (b), the second embossing step of the thermoplastic paint 32 is performed at an elevated temperature where the compensation layer 80 is elastic. Therefore, the hardened UV embossing paint area 42 is partially pressed into the compensation layer 80 by the hard embossing mold 70. This prevents deformation or damage to the embossing structure 44 and simultaneously allows embossing of the embossing paint layer 32.

[0119] To ensure that the UV embossing area 42 is sufficiently indented, the thickness of the compensation layer 80 should be slightly greater than the height difference to be compensated, which is typically between 2 and 15 μm for a typical embossed microstructure 44. The compensation layer 80 can also advantageously be deformed such that, when the UV embossing area 42 is indented, the thermoplastic embossing area 32 is simultaneously pressed slightly upwards, thereby supporting a second embossing. Such deformation can be performed in a volume-invariant manner.

[0120] After the second imprinting step is completed and the thermoplastic imprinting paint 32 cools and is demolded, the deformation of the elastic compensation layer 80 subsides, thereby allowing the resulting feature layer 24 to be provided with desired, aligned double imprinted portions 34, 44 in the feature regions 30, 40, such as... Figure 8 As shown in (c).

[0121] The design schemes described so far are based on the condition that the embossing areas already registered in feature regions 30, 40 exist on the carrier film. Now, some advantageous possibilities are described for applying two or more different embossing areas in the feature layer, which do not have registration fluctuations and therefore ideally do not have unintentional gaps or overlaps.

[0122] This section first describes a variation utilizing surface energy or surface tension phenomena. Depending on the material of the carrier film used, it may be necessary to first coat the carrier film with a coating having appropriate surface energy. For this purpose, additional coatings may be required, such as a primer layer or a release layer (or release layer) for subsequent separation. Corona treatment, plasma treatment, or flame treatment of the film may also contribute to obtaining sufficient adhesion. In the following description, the carrier 90 is considered to be or comprises a suitable carrier film and may have been pretreated or coated with other layers accordingly to provide surface energy suitable for the respective method.

[0123] exist Figure 8 In the illustrated method variation, the carrier 90 is first printed in the feature region 40 with a formulation 42 by any method. This formulation is imprintable and, after drying, is hydrophilic, possessing the desired color or transparency in the feature region 40. In this design, the formulation is a UV imprinting varnish 42, which, after being printed into the feature region 40, is imprinted with an associated imprint structure 44 and finally cured by UV crosslinking, such as... Figure 8 As shown in (a). Here, the feature area 30 is initially uncoated and presents an area with a hydrophobic surface.

[0124] Then, the carrier film equipped with the UV imprinting paint is wetted with wetting agent 92 either online or in a separate process. During this process, only the characteristic regions 40 of the hydrophilic coating receive the wetting agent 92, while the hydrophobic characteristic regions 30 remain unwetted, such as... Figure 8 As shown in (b).

[0125] Then, a second layer of thermoplastic embossing varnish 32 is applied to the carrier film. For this purpose, in this embodiment, a printing roller 94 is used, on which the embossing varnish layer 32 is applied across its entire surface. Figure 8 As shown in (b). In order to apply the printing ink 32 only to the gaps 30 between the already coated areas 40, the surface of the printing cylinder 94 is equipped with a compressible element 96.

[0126] like Figures 5 to 7 As shown in (c), during the printing of the imprinting enamel layer 32, the compressible element 96 deforms due to the pressure tip generated by the hardened UV enamel layer 42, thereby causing the imprinting enamel 32 in the non-protruding feature area 30 to come into contact with the carrier 90 and be transferred there, without damaging the existing imprint structure 44. Although the UV imprinting enamel 42 in the feature area 40 also comes into contact with the imprinting enamel layer 32 during the printing process, the UV imprinting enamel is ink-repellent and does not accept the imprinting enamel 32 due to the previously applied wetting agent 92.

[0127] In this way, the thermoplastic embossing varnish 32 is deposited only in the feature areas 30 during the printing step, such as... Figure 9 As shown in (d), UV printing ink 42, which has been imprinted and cured, exists in the feature region 40. The intermediate product thus obtained can then be used, for example, regarding... Figure 9 It can be further processed as described, and the desired embossing portion can also be provided for the embossing layer 32. Instead of thermoplastic embossing paint, other UV embossing paints can also be used. Since the first embossing paint has already cured when printing other embossing paints, the other UV embossing paints can also have the same curing characteristics as the first embossing paint.

[0128] exist Figure 8 In a variation of the method, a soft top pressure roller 98 with a Shore hardness of less than 90, especially less than 85, is used to replace the compressible element in the printing cylinder.

[0129] exist Figure 9 The original case shown in (a) basically corresponds to Figure 9 The original state is shown, and a carrier 90 is coated in the feature regions 40 with a UV imprinting varnish 42, which is hydrophilic after curing. The UV imprinting varnish 42 is imprinted with the desired imprinted structure 44 and cured by UV crosslinking. The carrier film thus coated is then wetted online or in a separate process by a wetting agent 92, wherein only the feature regions 40 of the hydrophilic coating receive the wetting agent 92, while the uncoated feature regions 30 remain unwetting.

[0130] Subsequently, a second layer of thermoplastic impression coating 32 is applied to the entire surface of the printing cylinder 94. A soft top pressure roller 98 provides counter-pressure for the printing step, but due to its lower hardness (below 90 or 85 Shore A), the top pressure roller can be locally deformed by the pressure tip. (As in...) Figure 10 As schematically shown in (b), during the printing of the embossing layer 32, the hardened UV embossing area 42 and the carrier film 90 are gently pressed into the soft top pressure roller 98 by the printing roller 94, so that the thermoplastic embossing 32 in the feature area 30 comes into contact with the carrier film 90 and is transferred there, without damaging the existing embossing structure 44.

[0131] Although the UV embossing paint area 42 is also in contact with the embossing paint layer 32, it is ink-repellent due to the applied wetting agent 92 and therefore does not accept the embossing paint 32. Thus, by the printing step, a shape is formed having unembossed thermoplastic embossing paint 32 in the feature area 30 and embossed, hardened UV embossing paint 42 in the feature area 40, which can then be further processed as described above. Alternatively, other UV embossing paints can be used instead of thermoplastic embossing paints, since the first embossing paint has already cured when the other embossing paint is printed, and therefore the other UV embossing paints can also have the same curing characteristics as the first embossing paint.

[0132] In this variant, the carrier film 90 must be sufficiently malleable under the printing conditions of the second printing ink 32 to allow for printing via the top pressure roller 98. Figure 10 The height compensation shown in (b) can be achieved for this purpose, for example, by using a very thin carrier film 90 (thickness preferably less than 23 μm, especially 19 μm, especially between 6 μm and 15 μm) and / or by using a carrier film 90 with a low glass transition temperature that exceeds the printing conditions of the second imprinting ink, thus making the film particularly susceptible to deformation.

[0133] Another possibility is to incorporate a compensation layer 80 within the layered structure of the anti-counterfeiting element itself. (See reference) Figure 9 On the carrier film 22, a compensation layer 80 is arranged in the layer structure of the anti-counterfeiting element to be manufactured. This compensation layer is flexible at least under the printing conditions of the embossing paint layer 32, and preferably has elastic properties.

[0134] In addition to the compensation layer, Figure 10 The original situation shown in (a) is the same as Figure 10 Corresponding to the original case in (a), a carrier film 22 is shown with an applied compensation layer 80, for example made of silicone rubber, coated in the feature areas 40 by a UV imprinting varnish 42, which is hydrophilic after curing. The compensation layer may also be provided with a thin overlay to facilitate subsequent application of the imprinting varnish layers 32, 42 and / or to provide suitable surface energy. The UV imprinting varnish 42 is imprinted with the desired imprinted structure 44 and cured by UV crosslinking. The carrier film thus coated is then wetted online or in a separate process by a wetting agent 92, wherein only the hydrophilic coated feature areas 40 receive the wetting agent 92, while the uncoated feature areas 30 remain unwetting.

[0135] Then, a second layer of thermoplastic embossing varnish 32 is applied to the entire surface of the printing cylinder 94. For example... Figures 8 to 10As shown in (b), the compensation layer 80 is elastic under the printing conditions of the thermoplastic varnish 32, so the hardened UV embossing varnish area 42 is partially pressed into the compensation layer 80 by the printing roller 94. This prevents deformation or damage to the embossing structure 44 and allows the embossing varnish layer 32 to be applied precisely into the gap 30 between the UV embossing varnish areas 42 without any problems.

[0136] In order for the UV embossing area 42 to be pressed in far enough, the thickness of the compensation layer 80 should be slightly greater than the height difference that needs to be compensated, which is typically between 2 and 15 μm.

[0137] Although the UV embossing varnish area 42 is also in contact with the embossing varnish layer 32, the UV embossing varnish area is ink-repellent and therefore does not accept the embossing varnish 32 due to the applied wetting agent 92.

[0138] After the printing process is completed, the deformation of the elastic compensation layer 80 subsides, thereby forming a layer on... Figure 11 The desired shape shown in (c) has an unprinted thermoplastic embossed paint 32 in the feature region 30 and an embossed, hardened UV embossed paint 42 in the feature region 40, and the shape can be further processed as described above.

[0139] If a particularly high-resolution structuring of the UV embossed varnish layer 42 is required in the aforementioned shape, the embossed varnish layer 42 can also be applied in a residue-free embossing process, as described in principle in patent document EP 3 230 795 B1, instead of as in Figure 11 In the embodiments, the embossed paint layer 42 is printed in a structured manner.

[0140] In order to successfully perform this high-resolution, residue-free imprinting, the surface energy of the carrier, the surface energy of the imprinting die used, and the surface tension of the imprinting varnish must be matched.

[0141] refer to Figures 8 to 10 (a) In the method, UV embossing varnish 42 is first applied to the entire surface of the carrier 90. The structured embossing die 100 includes die regions 102, 104 with different height levels, the shape and size of which correspond to feature regions 30 (protruding die region 102) or 40 (recessed die region 104). The desired embossing structure 44 of the feature region 40 is arranged in the recessed die region 104, which is further away from the layer 42 to be embossed in subsequent embossing steps.

[0142] As the structured embossing die 100 approaches the entire, yet uncured, embossing varnish layer 42, the protruding region 102, due to its geometry, reduces the existing thickness of the embossing varnish layer 42 at that location through compression. More specifically, due to the wetting properties of the embossing varnish 42, the splitting coefficient, i.e., the interfacial energy between the carrier 90 and the embossing varnish 42, and between the embossing varnish 42 and the structured embossing die 100, becomes negative. Therefore, the embossing varnish 42 is withdrawn from the feature region 30 below the protruding die region 102 back into the feature region 40 below the recessed die region 104.

[0143] This tendency to wet and dewet is related not only to surface energy but also to layer thickness. Therefore, in the feature region 30, the protruding mold region 102 of the embossing die 100 locally causes residue-free dewetting of the embossing ink 42 upon approach. The embossing ink 42 collected in the feature region 40 is then embossed by the embossing structure 44 arranged in the recessed mold region 104.

[0144] Therefore, after the embossed paint 42 has cured, the carrier film 90 contains the desired high-resolution structure having embossed, cured UV paint regions 42 and uncoated feature regions 30 therebetween, such as... Figure 12 As shown in (b). Then, for example, further processing can be carried out, such as with... Figure 12 As described in the relevant text.

[0145] Based on other variations of methods that also utilize surface energy or surface tension phenomena, refer to Figure 12 (a) First, a layer of first imprint varnish 32 is printed on the carrier 90. The first imprint varnish has a particularly low surface energy after drying or cross-linking. The printed first imprint varnish 32 is imprinted and then dried or hardened. Here, the first imprint varnish 32 is applied in a structured manner, so that there are characteristic areas 30 with the first imprint varnish and uncoated characteristic areas 40 without the imprint varnish. It has proven advantageous here that the first imprint varnish 32 is applied to approximately half of the total area to be coated.

[0146] Subsequently, a second embossing paint formulation 42, which has low viscosity and high surface tension, is applied evenly to the entire surface. This is equivalent to... Figure 12 The intermediate step shown in (a) is as follows. The second type of printing ink formulation 42 can be a UV printing ink, especially a formulation that can be diluted with water, which may require physical drying before printing.

[0147] Due to its low viscosity and high surface tension, the second formulation 42 dewets from the first embossing varnish 32, which has a lower surface energy, such as... Figure 12 As indicated by arrow 110 in (a), therefore, after dewetting, a Figure 13The situation is shown in (b). In the case of... Figure 13 In the case of complete dewetting as shown in (b), the coating of the second imprint varnish formulation 42 can also be repeated multiple times, thereby continuously constructing a material with high surface tension in the feature region 40 until there is a sufficient amount of the second imprint varnish 42 for the desired second imprint.

[0148] In addition to the described utilization of surface energy and surface tension phenomena, there is also the advantageous possibility of applying two or more different imprinting paint layers side by side without registration fluctuations based on layer removal, now with Figure 13 and 14 These favorable possibilities will be described in more detail.

[0149] First refer to Figure 13 A first layer made of a first thermoplastic embossing paint 42 having a desired first color is applied to a carrier film 22 in a structured manner, and the first layer is dried. The application of the first embossing paint 42 is achieved in a structured manner within a pattern of the feature regions 40, but the first embossing paint has a layer thickness d1 greater than the final actual required layer thickness d0, such as... Figure 13 As shown in (a).

[0150] Then a second layer made of a second thermoplastic embossing paint 32 with the desired second color is applied to the entire surface. For example... Figure 13 As shown in (b), it is advantageous to apply a second embossing varnish 32 with a layer thickness d2 > d1, but in principle, it is also sufficient to apply a second embossing varnish with a layer thickness d2 > d0. The application of the second embossing varnish 32 can also be carried out in multiple steps and in combination with wiping or scraping steps, so as to keep the layer thickness of the second embossing varnish 32 on the first applied embossing varnish area 42 low.

[0151] After the second imprinting ink 32 has cured or physically dried, the resulting structure is mechanically removed to the desired layer thickness d0, for example, by milling the layer region 122 protruding beyond layer thickness d0 using milling 120. If the milling cutter 120 is set to the desired target layer thickness, in the simplest case, this target layer thickness can be milled to, in which the two imprinting inks 32 and 42 are precisely arranged side-by-side and exposed in the feature regions 30 and 40, such as... Figure 13 As shown in (c).

[0152] Fine-tuning and feedback in milling step 120 can be achieved by milling away material, i.e., removing material from layer region 122. For example... Figure 14As shown in (b), during milling, initially when the layer removal amount 124 is still small, only the higher portion of the second embossing varnish 32 material is removed; only when the layer removal amount is large is the material of the first embossing varnish 42 also removed. Therefore, the desired removal depth can be controlled by spectral analysis, or, if necessary, simply by checking the color of the milled material. This ensures that the excess portion of the second embossing varnish 32 present on the first embossing varnish area 42 is completely removed and reliably achieves the desired removal depth. Figure 14 The final position shown in (c).

[0153] exist Figure 14 In other design schemes, two different imprinting inks are used to produce feature layer 24, one of which is soluble in the removal medium and the other is insoluble in the removal medium.

[0154] First refer to Figure 14 (a) On the carrier film 22, a first-color UV imprinting varnish 42 is first applied in a structured manner to the feature areas 40. The UV imprinting varnish 42 is typically imprinted with the desired imprint structure 44 and then cured. The feature areas 30 located between the imprinting varnish areas 42 ideally remain completely uncoated.

[0155] Then a thermoplastic embossing varnish 32 with a second color is provided, for which there is a matching removal medium by which the dried embossing varnish 32 can be removed at a well-defined removal rate, but the removal medium does not dissolve the UV embossing varnish 42.

[0156] like Figure 14 As shown in (b), the second layer is applied evenly to the carrier film 22 by means of this imprinting varnish 32. The application can be performed, for example, by flexographic printing, in which a flexographic sleeve has pressed a considerable portion of the imprinting varnish 32 into the recesses 130 between the hardened UV imprinting varnish areas 42 under high pressure, and only a relatively small amount of ink remains on the imprinting varnish areas 42.

[0157] Directly after applying the printing ink 32, the ink is still liquid, so excess can be wiped or scraped off the printed film, particularly from the hardened printing ink areas 42. After the physical drying of the printing ink 32, the recesses 130 between the hardened UV printing ink areas 42 are partially filled, such as... Figure 14 As shown in (b). A coloring film (or colored film) 132 formed of the printing ink material is also usually present on the printing ink area 42.

[0158] like Figure 14As shown in (c), the embossing ink 32 is repeatedly applied and excess material is removed until the recess 130 is fully filled or even overfilled. This repetition improves the relationship between the degree of filling of the recess 130 and the undesirable hue 132 of the embossing ink area 42. Here, it may be desirable to change the color concentration of the embossing ink 32 during the gradual filling process, especially towards increasingly lower color concentrations, because during wiping or scraping, the hue of the corresponding penultimate application step will also decrease, thereby reducing the proportion of undesirable color on the embossing ink area 42.

[0159] After the final repetition of application and wiping or scraping, the thermoplastic embossing paint 32 is physically dried, thus forming... Figure 14 The situation shown in (c) is as follows.

[0160] The impression ink 32 is then developed using a suitable removal medium. The removal medium can be aqueous with a defined pH value, or it can be solvent-based. It may be necessary to expose the impression ink 32 before removal.

[0161] Once the printing ink 32 has been sufficiently removed by the removal medium to expose the printing ink area 42, the removal process is stopped, for example, by rinsing with another medium. The cured UV printing ink 42 is not removed by the removal medium of the printing ink 32, thus achieving exposure with high selectivity.

[0162] After the removal step is completed, a desired structure exists on the carrier film 22, the structure having a feature region 40 and a feature region 30 located therebetween, the feature region 40 having a first-color imprinted UV embossed paint layer 42, and the feature region 30 having a second-color unimprinted thermoplastic embossed paint layer 32, such as... ​ As shown in (d). Further processing can, for example, follow the methods already described.

[0163] exist ​ In this method, other thermoplastic printing inks can also be used instead of UV printing ink 42. These other thermoplastic printing inks may be insoluble in the removal medium of printing ink 32 from the outset, or they may contain a crosslinking agent that makes the other thermoplastic printing ink insoluble in the removal medium of printing ink 32, but at the time of the first printing, the crosslinking reaction of the crosslinking agent has not progressed to a level that could prevent printing. Such a crosslinking agent could be, for example, an isocyanate, wherein if printing is to be performed at a certain time after the coating step, the use of an aliphatic isocyanate will result in a slower reaction.

[0164] The application of the first embossing layer 42 can be achieved by applying the desired visual object in a structured manner onto the feature region 40. However, especially in the case of UV embossing paint, it is also possible to first apply the embossing layer across the entire surface and then structure the embossing layer as desired. The advantageous possibilities for this, particularly for high-resolution structuring of UV embossing paint layers, have already been described above. If a thermoplastic embossing paint is applied as the first embossing layer, it may be necessary to print at an elevated temperature or from the melt, provided the layer thickness is sufficient, to successfully achieve fine structuring.

[0165] Before and / or after imprinting the first imprinting layer 42, other method steps may be provided to transform the imprinting paint into a fixed and / or imprintable form. These steps may include, for example, an exposure step or an annealing step. A wet chemical treatment may also be provided, in which the imprinting paint is contacted with a liquid medium to achieve hardening or cross-linking.

[0166] List of reference numerals

[0167] 10 banknotes

[0168] 12 Anti-counterfeiting components

[0169] 14 Observers

[0170] 20 Anti-counterfeiting components

[0171] 22 Carrier membrane

[0172] 24 Feature Layer

[0173] 30 Feature Regions

[0174] 32 Embossing paint layer

[0175] 34 Embossing Structure

[0176] 34' Incompletely formed imprinted structure

[0177] 40 Feature Regions

[0178] 42 Embossing paint layer

[0179] 44 Embossing Structure

[0180] 50, 52 Imprinting Dies

[0181] 60 Flexible embossing molds

[0182] 62 Deformation section

[0183] 64 Transition Zone

[0184] 70 Hard Imprinting Die

[0185] 72 Soft Imprint Roller

[0186] 74 Carrier Membrane

[0187] 80 Compensation Layer

[0188] 90 carriers

[0189] 92 Wetting agent

[0190] 94 Printing Rollers

[0191] 96 Compressible elements

[0192] 98 Soft Imprint Roller

[0193] 100 Structured Imprinting Dies

[0194] 102 Prominent mold area

[0195] 104 Recessed mold area

[0196] 110 Remove moisture

[0197] 120 milling cutter

[0198] 130 concave area

[0199] 132 Toning Film

Claims

1. An optically variable security element for providing security for value documents, having a feature layer, which feature layer comprises first and second feature areas arranged side by side on the same level and in register with one another in a common plane, wherein - the first feature area comprises a first embossing lacquer layer made of a first embossing lacquer, into which embossing structures producing a first optical effect are embossed, and - the second feature area comprises a second embossing lacquer layer made of a second embossing lacquer, into which embossing structures producing a different second optical effect are embossed, and - the first and second embossing lacquers have both different curing properties and different optical properties.

2. The security element according to claim 1, characterized in that The first and second embossing lacquers are formed by thermoplastic embossing lacquers having different softening temperatures, respectively.

3. The security element according to claim 1, characterized in that The first embossing lacquer is formed by a radiation-hardening embossing lacquer, and the second embossing lacquer is formed by a thermoplastic embossing lacquer.

4. A security element according to any one of claims 1 to 3, characterised in that The first and second embossing lacquers have different colors, different transparencies and / or different luminosity.

5. A security element according to any one of claims 1 to 3, wherein the first and second layers are formed from a material which is substantially transparent to visible light. The embossing structures of the first and second embossing lacquer layers have structure sizes in the plane of between 30 μm and 200 μm, respectively.

6. A security element according to any one of claims 1 to 3, characterised in that Between the embossing structures of the first and second embossing lacquer layers there is a narrow transition area having less than 10 μm, in which the embossing height and / or the embossing quality of one of the embossing structures is reduced.

7. A security element according to any one of claims 1 to 3, wherein the first and second layers are formed from a material which is substantially transparent to visible light. The embossing lacquer layers of the first and second feature areas are arranged side by side without gaps and overlaps.

8. A security element according to any one of claims 1 to 3, wherein The first and second embossing lacquer layers are provided with a common enhancement reflection coating.

9. A security element according to any one of claims 1 to 3, wherein The security element has a deformable carrier film having a thickness of less than 23 μm, or a carrier film having a glass transition temperature Tg which is less than the softening temperature of at least one thermoplastic embossing lacquer of the feature layer.

10. A security element according to any one of claims 1 to 3, wherein The security element comprises a compensation layer which is flexible at the softening temperature of at least one thermoplastic embossing lacquer of the feature layer.

11. A method for manufacturing an optically variable security element, wherein Producing a feature layer on a carrier, which feature layer comprises first and second feature areas arranged side by side on the same level and in register with one another in a common plane, wherein in the method - a first embossing lacquer layer made of a first embossing lacquer is applied in the first feature area and embossing structures producing a first optical effect are embossed into the embossing lacquer layer, and - a second embossing lacquer layer made of a second embossing lacquer is applied in the second feature area and second embossing structures producing a different second optical effect are embossed into the embossing lacquer layer, and - wherein as first embossing lacquer and second embossing lacquer the following embossing lacquers are applied, which have both different optical properties and different curing properties, and / or are cured at different points in time.

12. The method according to claim 11, characterized in that - a first embossing lacquer layer made of a thermoplastic embossing lacquer having a higher softening temperature is applied in the first feature area and a second embossing lacquer layer made of a thermoplastic embossing lacquer having a lower softening temperature is applied in the second feature area, - the first embossing step is performed at a higher temperature and the first embossing lacquer layer is provided with first embossing structures here, and - the second embossing step is performed next at a lower temperature and the second embossing lacquer layer is provided with second embossing structures here.

13. The method according to claim 11, characterized in that - a first embossing lacquer layer made of thermoplastic embossing lacquer is applied in the first feature area and a second embossing lacquer layer made of radiation-hardening embossing lacquer is applied in the second feature area, - the first embossing step is performed at a higher temperature and the first embossing lacquer layer is provided with first embossing structures here, and - the second embossing step is performed next at a lower temperature and the second embossing lacquer layer is provided with second embossing structures here and hardened.

14. The method according to any one of claims 11 to 13, characterized in that In the first embossing step, the first embossing lacquer layer is embossed and solidified, while the second embossing lacquer layer remains deformable and flows partially or completely after the first embossing step.

15. The method according to claim 11, characterized in that - a first embossing lacquer layer made of radiation-hardening embossing lacquer is applied in the first feature area and a second embossing lacquer layer made of thermoplastic embossing lacquer is applied in the second feature area, and - the first embossing step is performed at a higher temperature and the first embossing lacquer layer is provided with first embossing structures here, and - the second embossing step is performed next at a lower temperature and the second embossing lacquer layer is provided with second embossing structures here and hardened.

16. The method of claim 15, wherein, In the second embossing step, second embossing structures are only transferred into the second embossing lacquer layer.

17. The method of claim 15 or 16, wherein, In the second embossing step, a flexible embossing die, a soft embossing top platen or a flexible compensation layer located in the layer structure of the security element is used in order to transfer second embossing structures only into the second embossing lacquer layer.

18. An embossing assembly comprising - a security element semi-finished product for further processing into an optically variable security element according to any one of claims 1 to 10, the security element semi-finished product having a feature layer comprising a first feature area and a second feature area arranged side by side at the same height and in register with each other in one common plane, wherein - the first feature area comprises an embossing lacquer layer made of solidified embossing lacquer, into which embossing structures producing a first optical effect are embossed, and - the second feature area comprises a second embossing lacquer layer made of uncured embossing lacquer, - wherein the first and second embossing lacquers have both different solidification properties and different optical properties, and - a flexible embossing die having second embossing structures for embossing embossing structures producing a second, different optical effect only into the embossing lacquer layer of the security element semi-finished product having uncured embossing lacquer.

19. The impression assembly of claim 18, wherein The flexible embossing die is formed from silicone rubber.

20. An embossing assembly comprising - a security element semi-finished product for further processing into an optically variable security element according to any one of claims 1 to 10, said security element semi-finished product having a feature layer comprising first and second feature areas arranged side by side on the same level and in register with each other in one common plane, wherein - the first feature area comprises a layer of embossing lacquer made of cured embossing lacquer, into which embossing structures producing a first optical effect are embossed, and - the second feature area comprises a second layer of embossing lacquer made of uncured embossing lacquer, - wherein the first and second embossing lacquers have both different curing properties and different optical properties, and - a hard embossing die having second embossing structures and a soft embossing top roller having a Shore hardness of less than 90 for embossing embossing structures producing a second, different optical effect only into the layer of embossing lacquer having uncured embossing lacquer in such a way that the security element semi-finished product is embossed between the hard embossing die and the soft embossing top roller.

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