Planar sealing element

Abstract

The present invention relates to a planar sealing element (1) for application onto a substrate (2), comprising a backing layer (3), an adhesive layer (8) for attachment to the substrate and at least one, preferably several, functional layer(s) (4) between the backing layer and the adhesive layer, wherein the at least one functional layer is a colour display layer (5), wherein the backing layer has a surface quality and / or the backing layer furthermore comprises an adhesion-controlling layer (6) as a further functional layer, such that the backing layer can be at least partially detached from the functional layer in order to bring the sealing element from a first state (9) into a second state (10), wherein the second state cannot be transferred to the first state, wherein the sealing element in the second state comprises a peeled-off layer (11), comprising at least the partially detached backing layer, and a residue (12), comprising at least parts of the adhesive layer and at least parts of the at least one colour display layer, and wherein the backing layer is produced from a translucent or transparent plastic, wherein according to the invention, the backing layer has nanostructures and / or microstructures (13) on at least one of its surfaces, wherein, when the peeled-off layer is arranged congruently on the residue, the peeled-off layer has, at least in a region in which no or only very small amounts of the at least one colour display layer adhere, a different colour impression in at least one region compared with the same region of the backing layer in the first state when viewed in the direction of the backing layer.

Description

[0001] FLAT SEALING ELEMENT

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a flat sealing element for application to a substrate, comprising a carrier layer and at least one, preferably several, functional layer(s), wherein the at least one functional layer is a color representation layer, wherein the sealing element further comprises an adhesive layer for attachment to the substrate, wherein the at least one functional layer is arranged between the carrier layer and the adhesive layer, wherein the carrier layer has a surface quality and / or the carrier layer further comprises an adhesion-controlling layer as a further functional layer, so that the carrier layer is at least partially detachable from the at least one functional layer in order to bring the sealing element from a first state into a second state, wherein the second state cannot be converted into the first state,wherein the sealing element in the second state comprises a peeled layer comprising at least the at least partially detached carrier layer and a residue comprising at least parts of the adhesive layer and at least parts of the at least one color representation layer, and wherein the carrier layer is made of a translucent or transparent plastic.

[0004] STATUS OF THE ART Sealing elements, e.g. sealing films, are already known in the state of the art. They are used for security purposes. In addition to protecting containers or packaging from unauthorized opening, flat sealing elements can also be used to cover confidential information. The confidential information could be, for example, a PIN code, an identity code or a hologram. The confidential information only becomes visible to the viewer when the carrier layer is removed. In addition, sealing films, which by their nature indicate detachment or repositioning, are also used for the tamper-proof fixing of security features such as holograms or product identity codes to a product or packaging.

[0005] Such sealing films known in the state of the art are also mostly made of plastic, but this is a smooth, shiny plastic that is usually transparent.

[0006] For example, AT 9365 U discloses a sealing film that clearly and irreversibly indicates the opening of a sealing element. The sealing film, or more precisely its carrier layer, is made of plastic, preferably polypropylene, with a smooth surface.

[0007] In sealing elements known in the prior art - including that of AT 9365 U - a color representation layer with a defined proportion of opaque white pigments is often used, which partially or completely separates from other layers when the sealing element is removed, thus leaving behind a clearly visible color change when the sealing element is glued back on. Since a color representation layer with opaque white pigments only produces a low opacity, a disadvantage of the sealing elements known in the prior art is that the residue of the sealing element only shows a slight color change when the carrier layer has been completely removed.

[0008] If, however, in the prior art, a strong color such as red or dark blue is used in the color representation layer, the changes in the residue are very clear, but in the glued-back state (when the peeled-off layer is arranged congruently on the residue) they are less easily recognizable and in particular not equally visible from all viewing angles, but sometimes only with difficulty, so that the untrained eye could overlook any manipulation.

[0009] OBJECT OF THE INVENTION

[0010] It is an object of the present invention to provide a flat sealing element with a translucent or transparent plastic carrier layer, which overcomes the disadvantages of the prior art and enables a change in the color impression similar to that achieved by a white-pigmented color layer, but without the application of such a layer, while at the same time achieving equally good or even improved security functions compared to sealing elements known in the prior art. Furthermore, a sealing element is to be provided with which color changes of the sealing element are more easily detectable upon manipulation of the sealing element than with sealing elements known in the prior art. SUMMARY OF THE INVENTION

[0011] The stated object is achieved by a flat sealing element according to claim 1.

[0012] Claim 1 is based on a flat sealing element for application to a substrate, comprising a carrier layer and at least one, preferably several, functional layer(s), wherein the at least one functional layer is a color representation layer, wherein the sealing element further comprises an adhesive layer for attachment to the substrate, wherein the at least one functional layer is arranged between the carrier layer and the adhesive layer, wherein the carrier layer has a surface quality and / or the carrier layer further comprises an adhesion-controlling layer as a further functional layer, so that the carrier layer is at least partially detachable from the at least one functional layer in order to bring the sealing element from a first state into a second state, wherein the second state cannot be converted into the first state, wherein the sealing element in the second state is a peeled-off layer,comprising at least the at least partially detached carrier layer, and a residue comprising at least parts of the adhesive layer and at least parts of the at least one color representation layer, and wherein the carrier layer is made of a translucent or transparent plastic.,

[0013] According to the invention, the carrier layer has nanostructures and / or microstructures at least on one of its surfaces, the peeled-off layer having, in at least one area in which no or only small portions of the at least one color representation layer adhere when the peeled-off layer is arranged congruently on the residue, a different color impression than the same area of ​​the carrier layer in the first state in any viewing direction of the carrier layer due to diffuse reflection by the nanostructures and / or microstructures.

[0014] The material of the carrier layer itself can generally be transparent or translucent. According to the invention, the transparency or translucency of the carrier layer is reduced by dif fuse reflection at the nano- and / or microstructures present on its surface, unless a functional layer is directly adhered to the carrier layer, which impedes or reduces this dif fuse reflection (also referred to as dif fuse scattering).

[0015] Due to the diffuse reflection caused by the nano- and / or microstructures, the color of a color representation layer on the residue, viewed through the peeled-off layer, no longer appears as intense in the second state as it did before the manipulation. Colors visible through translucent functional layers on the adhered substrate also no longer appear as intense in the second state, viewed through the peeled-off layer, as they did before the manipulation.

[0016] Due to the diffuse reflection, the change in the color impression (if at least one colored color representation layer is present, also referred to as color effect) is not only clearly visible at a steep viewing angle, as is the case with smooth carrier layers according to the prior art, but also at flat viewing angles, which makes manipulation of the sealing element easier to detect than with sealing elements known in the prior art.

[0017] It should be noted here that a changed color impression occurs regardless of whether the nanostructures and / or microstructures are present on the surface facing away from the functional layers or on the surface facing the functional layers. Because the second state cannot be converted into the first state, there will always be a gap between the removed layer and the residue when the removed layer is placed back on top of the residue.

[0018] The nanostructures and / or microstructures present on the surface of the carrier layer can be obtained by different manufacturing processes. So-called matting agents can be used, which are sprayed, painted, dipped, or printed onto the carrier layer. The matting agent contains additives comprising particles of different sizes, whereby after drying and evaporation of the solvent or through curing of the matting agent, an uneven surface is formed due to the existing nanostructures and / or microstructures. One suitable matting agent is fumed silicon dioxide, also called pyrogenic silicic acid.

[0019] Alternatively, the microstructures could also be created by embossing in the surface of the carrier layer, whereby the carrier layer is in a semi-solid state during embossing and then hardens. In this case, the nanostructures and / or microstructures are embossed directly on the surface of the carrier layer. Alternatively, a lacquer layer can be arranged on the carrier layer, which can be deformed in the liquid state to form the nanostructures and / or microstructures and only then hardens. As a further alternative, the microstructures could also be produced directly on the carrier layer or in a separate lacquer layer using UVC irradiation. Alternatively, the carrier layer could also be produced by casting, whereby a liquid or viscous plastic composition is poured into a mold.The mold contains the negative of the desired micro- and / or nanostructure geometry, so that these are retained accordingly on the cured film. After pouring, the film hardens and can then be removed and cut as desired.

[0020] Furthermore, it can be expected that similar effects to those achieved with the sealing element according to the invention, which has a carrier layer with nanostructures and / or microstructures arranged on the surface of the carrier layer, will also be obtained with inherently translucent carrier layers whose reduced transparency is attributable to the addition of additives during polymer production, i.e. which do not have any nanostructures and / or microstructures on the surface. Alternatively, bio-based and / or biodegradable plastics can be used which, due to their polymer composition or polymer structure, already have a roughened surface and / or turbidity.

[0021] Due to the roughness on the surface of the plastic caused by the existing nanostructures and / or microstructures, the carrier layer gives off a matte or cloudy impression, which is reduced by applying at least one functional layer directly to the carrier layer. The carrier layer then appears less matte or cloudy, i.e. more transparent, both when the at least one functional layer is applied to a surface of the carrier layer without nanostructures and / or microstructures, and when the at least one functional layer is applied to the surface of the carrier layer with nanostructures and / or microstructures. If the functional layers are applied directly to the side of the carrier layer where the nanostructures and / or microstructures are present during the manufacturing process, the cloudiness caused by these structures disappears almost completely. This design variant is explained in more detail below.

[0022] Particularly preferably, the carrier layer, if it is colorless, appears almost completely transparent after the application of the at least one functional layer. If the carrier layer is at least partially detached from the at least one functional layer, the carrier layer appears matt or less transparent again at the at least partially detached parts. This changed color impression of the detached carrier layer persists, even if the user attempts to reapply it to the residue.

[0023] It is noted that the nanostructures and / or microstructures can be present on the entire surface of the carrier layer, i.e. on the surface facing the functional layers and / or the surface facing away from the functional layers, or only on a section thereof. In other words, it can be provided that the nanostructures and / or microstructures are present over the entire area of ​​the carrier layer. Furthermore, it could be provided that the nanostructures and / or microstructures are present over the entire area of ​​the surface facing away from the functional layers and that the nanostructures and / or microstructures are sealed in certain areas, e.g. by means of a varnish.

[0024] The turbidity of the carrier layer provided with the nanostructures and / or microstructures can be used as a measure of the optical effect produced by the nanostructures and / or microstructures. The turbidity of a carrier layer according to the invention can be measured or determined, for example by measuring the turbidity according to the ASTM D 1003 or DIN ISO13468 standard for haze, or by measuring the gloss according to ASTM D2457. “Flat-area” in the context of the sealing element means that the width and length of the sealing element are considerably greater than the height or thickness. The sealing element is preferably a label, where the length and width are fixed, or an adhesive tape, i.e. where there is a tape with a defined width and the length can be fixed by the user.

[0025] The flat sealing element can be converted from a first state to a second state, wherein the conversion occurs by at least partially detaching the carrier layer from the functional layers. The result of this conversion from a first to a second state is a changed color impression. This is achieved by arranging a carrier layer that is not completely transparent but merely translucent, i.e., a carrier layer with a certain degree of opacity, on the functional layers in the first state.In order that the carrier layer can be transferred from a first state to a second state, the carrier layer of the sealing element according to the invention is designed in such a way that the carrier layer has a surface quality, in particular a suitable surface tension, so that the carrier layer can be at least partially detached from the at least one functional layer, and / or that the carrier layer comprises an adhesion-controlling layer as a further functional layer, so that the carrier layer can be at least partially detached from the at least one functional layer.

[0026] If an adhesion-controlling layer is to be used, the plastic film, which forms the carrier layer and generally has a low surface tension, is coated with a so-called top coat with a high surface tension. Only then are the desired areas of the plastic film coated with an adhesion-controlling layer to achieve the desired surface tension, which is in turn lower than that of the top coat.

[0027] The adhesion-controlling layer can be applied over the entire surface or in sections to form symbols, etc. and prevents the permanent connection of the carrier layer with the at least one functional layer that follows the adhesion-controlling layer.

[0028] The simplest embodiment of the planar sealing element according to the invention can essentially be described as follows: Between the carrier layer and the adhesive layer, only an adhesion-controlling layer and a color representation layer are arranged as functional layers, or only one color representation layer if the carrier layer has a specific surface quality, so that the carrier layer can be at least partially detached from the color representation layer.

[0029] In the second state, the sealing film according to the invention has a peeled-off layer comprising at least the carrier layer and a residue which remains adhered to the substrate and comprises at least the adhesive layer (or substantial parts thereof) and at least parts of the at least one color representation layer.

[0030] By removing the carrier layer a changed color impression is achieved. This means that in a first state of the flat sealing element the entire surface appears blue, for example, because the color representation layer is colored blue and is almost completely visible through the translucent plastic carrier layer. By removing the peeled off layer the sealing element is converted into a second state in which the color appearance of the residue is somewhat more intense. This results from the fact that the carrier layer will generally appear translucent, i.e. matt or cloudy, so that the color of the functional layers will naturally appear more intense without the carrier layer above it. The changed color impression according to the invention occurs, however, when the carrier layer is placed back on top of the residue so that it is congruent or...is glued back and the residue is viewed through the peeled-off layer: the colour of the residue then appears considerably lighter or paler or less intense than in the first state.

[0031] It goes without saying, however, that the said changed color impression naturally only occurs in those areas of the carrier layer in which no or only small portions of the at least one color representation layer adhere to the carrier layer in the second state. In the remaining areas, i.e. in those areas in which color continues to adhere, the changed color impression is not present or is only barely recognizable. Small portions means in particular that color residues can continue to adhere to the carrier layer after the transfer from the first to the second state.

[0032] A further advantage of the invention is that the colour effect in the second state, when the peeled-off layer is re-applied congruently to the residue, can be seen from different viewing angles. This distinguishes the sealing element according to the invention from those known from the prior art, where this colour effect can only be perceived from certain angles. For example, in the case of sealing elements known from the prior art with a smooth surface of the carrier layer, tampering, i.e. a peeled-off layer that has been re-applied to the residue, can sometimes be difficult to detect from certain viewing angles. The nano- and / or microstructures present on the carrier layer of the sealing element according to the invention, in turn, significantly improve visibility, so that the colour effect is clearly perceptible from all viewing angles.This means that in the case of sealing elements according to the invention, the colour difference between the first state and the second state is perceived to a greater extent, particularly at a viewing angle of less than 90°: the incident light is diffusely reflected by the nanostructures and / or microstructures present on the surface of the carrier layer, which are in any case exposed in the second state.

[0033] A further advantage is that the sealing element cannot simply be transferred from one substrate to another. If this were attempted, the tampering with the sealing element would inevitably cause the carrier layer to detach from at least one functional layer, at least in some areas, leaving a residue on the tampered substrate. An observer would then be able to recognize that the sealing element in question had been tampered with.

[0034] The plastic carrier layer can be colorless or appear colored. Additives without pigments and / or dyes can be mixed into the colors, allowing carrier layers to be produced with high translucency, or additives containing pigments and / or dyes can be used to reduce the translucency accordingly, allowing the optical appearance of the plastic to be varied.

[0035] Because the carrier layer is cloudy due to the nanostructures and / or microstructures, the carrier layer itself takes on the function of a color representation layer. Unlike conventional carrier layers made of completely transparent plastic without nanostructures and / or microstructures, it is therefore not necessary to first apply another color representation layer with white pigments and / or colored pigments and / or dyes as the first color representation layer; instead, the carrier layer can be used directly. Of course, the carrier layer could also be colored, which would give it a matte colored appearance due to the nanostructures and / or microstructures.

[0036] The removal and thus transfer of the sealing element into the second state can be facilitated by a tab. The tab can be an additional element arranged on the carrier layer or a part of the carrier layer, with the tab extending beyond the adhesive layer.

[0037] If it is desired that the peeled-off layer does not separate completely from the residue, an area can be provided, e.g. at the edge of the sealing element, in which no adhesion-controlling layer(s) is applied or in which no specific surface quality is present, so that the functional layers and adhesive layer bond inseparably with the carrier layer. Complete removal of the peeled-off layer is therefore only possible by applying greater force. The peeled-off layer therefore remains on the flat sealing element. This reduces the loss of the sealing element into the environment. The sealing element can therefore also be recycled.

[0038] The sealing element according to the invention can in principle be applied to any substrate to which the adhesive layer adheres. Depending on the nature of the substrate, the composition of the adhesive layer can therefore be adapted accordingly. Preferably, however, the substrate will be surfaces or packaging made of the packaging materials paper, cardboard, paperboard, corrugated cardboard, glass, plastic, metal or composites. However, if the carrier layer is made of plastic, it is advantageous that the substrate is also made of a plastic in order to enable joint disposal and thus recycling wherever possible.

[0039] In one embodiment of the invention, systematically arranged, particularly regular, nanostructures and / or microstructures are provided at least in certain regions. Systematically arranged nanostructures and / or microstructures include specifically designed elevations that, for example, together form an image, but also regular nanostructures and / or microstructures, which here are understood to mean, in particular, identical elevations periodically arranged in the plane of the sealing element.

[0040] A planned arrangement of the nanostructures and / or microstructures is of course made possible above all by production by embossing into the carrier layer itself or into a lacquer or polymer layer present on the carrier layer or by casting the carrier layer into a corresponding mold, as already described in detail above.

[0041] In order to be able to produce a carrier layer with at least partially planned nanostructures and / or microstructures in a particularly simple manner, one embodiment of the invention provides that the nanostructures and / or microstructures are embossed, preferably on a lacquer layer arranged at least in sections on the upper side of the carrier layer, in particular a UV-cured lacquer layer or polymer layer.

[0042] The creation of an embossing tool for imprinting the nanostructures and / or microstructures makes it possible to obtain planned structures of any desired pattern on the substrate. The arrangement of the nanostructures and / or microstructures can therefore be adapted as needed, as described in detail above. The embossing tool can also be provided in the form of a film containing these nanostructures and / or microstructures, which are transferred into the not fully cured lacquer.

[0043] In principle, however, the production of planned nanostructures could also be achieved with the help of an additional layer of lacquer that is painted or otherwise applied to the carrier layer.

[0044] In order to enable particularly simple production of the nanostructures and / or microstructures on the surface of the carrier layer without specially manufactured embossing rollers or molds, a further embodiment of the invention provides for randomly arranged nanostructures and / or microstructures to be present at least in some regions. These have randomly arranged elevations whose respective location in the plane of the sealing element cannot be determined in advance. A wide variety of methods, in particular simple ones, are used for this, such as spraying or painting on paints with additives that only permit a random arrangement of nanostructures and / or microstructures. The production of the nanostructures and / or microstructures in a random arrangement takes place in particular by spraying, painting or printing a matting agent onto the carrier layer or by dipping the carrier film into a matting agent.The particles present in the matting agent are thus arranged randomly.

[0045] These nanostructures and / or microstructures can also be produced by arranging a further layer with particles at least in sections on the upper side of the carrier layer, the particles of the further layer protruding at least in sections from the further layer in order to form the nanostructures and / or microstructures. This means that a further layer is applied to the carrier layer, by means of which the nanostructures and / or microstructures are formed. In order to produce the nanostructures and / or microstructures on the surface of the carrier layer, a further layer, preferably a lacquer layer, which comprises particles, is applied to the carrier layer at least in sections.During drying, the solvent evaporates at least partially, causing the particles to protrude from the further layer at least in sections and to form corresponding nanostructures and / or microstructures on the surface of the carrier layer.

[0046] In one embodiment of the invention, it is provided that the nanostructures and / or microstructures measured in the plane of the sealing element have a size of 50 nm to 200 pm, preferably 60 nm to 100 pm, particularly preferably 100 nm to 60 pm, in particular 500 nm to 60 pm.

[0047] If the nanostructures and / or microstructures have a size in this range, the color effect is particularly clearly visible.

[0048] For nanostructures and / or microstructures with a systematic arrangement, the size of the individual elevations is preferably in the range from 10 pm to 200 pm, in particular from 20 pm to 90 pm. For nanostructures and / or microstructures with a random arrangement, the size of the individual elevations is preferably in the range from 50 nm to 80 pm, in particular from 100 nm to 60 pm.

[0049] The mutual spacing of the individual elevations in the plane of the sealing element can be zero or smaller than the size of the individual elevation, in particular in the case of planned nanostructures and / or microstructures. The mutual spacing of the individual elevations in the plane of the sealing element can, however, also correspond to the size of the elevation or be a multiple of the size of the individual elevation, e.g. up to twice, three times, four times or up to ten times. When reference is made to regular nano- and / or microstructures, this generally refers to structures in which the individual structures occur with a uniform periodicity to one another. This means that the spacing between the individual nano- and / or microstructures is essentially the same. Particularly preferably, the extent of the individual structures normal to the plane of the sealing element is also essentially the same.

[0050] In one embodiment of the invention, it is provided that the nanostructures and / or microstructures, measured normal to the plane of the sealing element, have a size of more than 50 nm, preferably from 2 pm to 100 pm, particularly preferably from 3 pm to 50 pm.

[0051] Randomly arranged nanostructures and / or microstructures according to the invention typically have heights of 2 pm to 10 pm, e.g., around 6 pm. Planned nanostructures and / or microstructures according to the invention typically have heights of 3 pm to 30 pm.

[0052] Typically, carrier layers not according to the invention, i.e. a smooth film, only have elevations in the range of less than 50 nm, so that a height of the elevations according to the invention of more than 50 nm ensures the effect according to the invention.

[0053] In general, it should be noted that the turbidity measurement is, of course, carried out in the second state, i.e., when the carrier layer has been removed from the residue. The following describes that surface, i.e., side, of the carrier layer whose nanostructures and microstructures are relevant for the effect according to the invention. However, it cannot be ruled out that the other surface, i.e., the opposite side of the carrier layer, also has nanostructures and / or microstructures.

[0054] Sealing elements according to the invention preferably have on the carrier layer, in particular the side of the carrier layer on which the nano- and / or microstructures are arranged, a gloss of between 0% and 40%, which gloss is measured according to ASTM D2457, and a haze in the range from 30% to 100%, preferably however from 70% to 80%, which haze is measured according to ASTM D 1003 or DIN ISO13468.

[0055] In contrast, sealing elements not according to the invention have a gloss of between 50% and 100% on the carrier layer and a haze in the range of 0% to 20%.

[0056] In one embodiment of the invention, all layers are at least translucent, at least in a congruent surface area. The carrier layer is in any case translucent due to the nanostructures and / or microstructures and not completely transparent; the remaining layers, such as the functional layers and / or the adhesive layer, can be either completely transparent or also translucent.

[0057] Advantageously, such a design of the flat sealing element enables information on the substrate to still be recognizable or readable when the sealing element is applied to a substrate, for example, packaging or the like. Recognizable or readable means that the information can be recognized or read both by the naked eye of a human observer and, alternatively, with electronic assistance.

[0058] This embodiment of the invention makes it generally possible to read information or symbols which are arranged below the sealing element, i.e. between the adhesive layer and the substrate, e.g. the packaging. It is therefore not necessary to remove or open the sealing element in order to read the information. At the same time, the information remains readable even if the sealing element was removed, for example when the package was opened. It is a common requirement, often regulated by law, that information, in particular batch, expiry date and other codes must remain readable through the sealing or subsequent opening of the packaging and the sealing element. In addition, the information or symbolsThe symbol on the packaging is also protected against manipulation of the information, for example by erasing or overwriting, by the sealing element glued over it.

[0059] In order to be able to recognize the information, it is of course necessary that the layers are all at least translucent (and not opaque) in essentially the same surface area in order to then have the desired translucency in a congruent surface area.

[0060] The transparency or translucency of the functional layers or the adhesive layer is achieved by their internal transparent or translucent structure, and / or by the absence or the low proportion of color pigments and / or by the thickness of the layers.

[0061] If the at least one functional layer and the adhesive layer are transparent or translucent only in a congruent surface area, it is possible to recognize information placed on the substrate below this surface area, while at the same time the remaining part of the sealing element can be opaque. In particular, if all layers are at least translucent in at least one congruent surface area, it can be provided that all layers are colorless in at least one congruent surface area. The effect when the sealing element is opened is then based only on the turbidity changing at least in some areas.

[0062] The advantage of this embodiment is that only a transparent layer is used as the functional layer, or more precisely, as the color representation layer. Additional color pigments are not required to create the color effect or altered color impression according to the invention. This makes it possible to produce a particularly discreet sealing element that nevertheless exhibits the same good security properties.

[0063] In order to prevent information arranged on the substrate from being recognized or read by a sealing element and at the same time to be able to produce a particularly high contrast between the first and second state, a further embodiment of the invention provides that at least one functional layer is opaque at least in one surface area.

[0064] The complete opacity of one or more functional layers, at least in a congruent or essentially congruent area, ensures that information arranged on the substrate (in particular printed, embossed, etched, or fibered) cannot be recognized in the first state. However, a code applied to the functional layers, for example, could be recognized in the second state of the sealing element, i.e., when the peeled-off layer has been removed.

[0065] At the same time, the opaque functional layer(s) ensure that the contrast of the color effect according to the invention can be particularly clearly recognized. This means that the intense yet opaque coloring of at least one color-representation layer as a functional layer makes the change in the color impression of the carrier layer even more clearly visible after the sealing element has been converted from the first state to the second state.

[0066] If the flat sealing element is used with opaque functional layers, the sealing element appears particularly intensely colored in its first state, for example, dark blue or dark green. When the sealing element is then transferred to a second state and the peeled-off layer is again aligned with the residue, a particularly high-contrast color effect can be seen. The carrier layer is now noticeably changed in color, so that the color of the residue underneath appears considerably weaker or more cloudy. Such a pronounced color effect is very easy and quick to recognize for an observer.

[0067] To cover information, a preferred design is one in which a symbol is formed by a color representation layer sandwiched between two adhesion-controlling layers. The first adhesion-controlling layer triggers the color change by partially detaching the opaque carrier layer. The second adhesion-controlling layer separates the lower, transparent or translucent layers from the opaque color representation layer, which adheres to the carrier layer in the area where the information is to be exposed.

[0068] In particular, a metallic layer can be part of the functional layer which is opaque at least in one surface area. The metallic layer is produced, for example, by vapor deposition or printing. The metallic layer can therefore be part of a color representation layer and appears rather shiny in the first state. If the carrier layer is peeled off during conversion to the second state and placed back on top of the residue, the areas where the metallic layer is in the residue appear much more matt when viewed through the carrier layer. As a metallization layer, the metallic layer is typically 4 nm thick. This is generally used in conjunction with a transparent lacquer layer because it is transferred from a carrier to the flat sealing element.

[0069] In order to achieve particularly good stability of the sealing element, so that the process of application to a substrate is facilitated, in a further

[0070] According to an embodiment of the invention, an additional carrier layer is arranged between a functional layer and the adhesive layer or between two functional layers.

[0071] The further carrier layer can be made of paper or plastic. If additional security against tampering with heat or against pulling, twisting or moving is to be achieved, then a deformable, i.e. in particular stretchable, further carrier layer made of plastic is advantageous. Such deformable films can be made of polyolefins, polyester, polyurethane or mixtures of these plastic types. Plastics that are easily deformable are particularly advantageous in this context, e.g. CPP and blends of PE and PP. The desired deformability is determined during production of the plastics. For example, cast or one-sided oriented plastic films with a thickness of between 10 μm and 100 μm, particularly preferably 30 μm to 60 μm, are suitable for sealing elements according to this embodiment of the invention. I.e.the carrier layer is not deformable, whereas the further carrier layer is deformable. Due to the different deformability properties of the two carrier layers with regard to heat and / or mechanical loads, e.g. due to pulling, twisting, shifting, etc., the bond between the two carrier layers and the functional layers or the adhesive layer is weakened and / or at least partially broken. This thermal and / or mechanical load thus converts the sealing element into the second state, whereby a gap is formed between the carrier layer and the further carrier layer and an irreversibly changed color impression and effect arises. This means that due to the thermal and / or mechanical deformation of the further carrier layer, the carrier layer and the further carrier layer can no longer be arranged on top of one another exactly as in the first state.It is therefore particularly advantageous if the additional carrier layer is highly deformable. High tamper resistance against heat and / or mechanical stress such as pulling, twisting, shifting, etc. is enhanced if the deformable film is additionally equipped with predetermined breaking points.

[0072] In one embodiment of the invention, the carrier layer has nanostructures and / or microstructures on a surface facing away from the functional layers. The surface facing the functional layers does not need to have nanostructures and / or microstructures.

[0073] This means that in the first state the nano- or microstructures are not embedded in the functional layers, so that a diffuse reflection occurs on this surface and makes it appear matt. However, in the second state the carrier layer, where it has been detached from the color representation layer, appears even less transparent and the residue underneath it, if it is colored, appears even less color-intensive. So here too there is a change in the color impression according to the invention. One possible explanation for this is that light penetrates through the distance between the peeled-off layer and the residue, passes through the carrier layer and is diffusely scattered by its nano- or microstructures, so that to the observer the carrier layer, where it has been detached from the color representation layer, appears more cloudy, or the residue underneath it appears less color-intensive.Due to the diffuse scattering, this effect can be clearly perceived even at a flat viewing angle, for example. The nano- and / or microstructures present on the carrier layer of the sealing element according to the invention significantly improve visibility, so that the color effect is clearly perceptible from all viewing angles.

[0074] In a preferred embodiment of the invention, the carrier layer has nanostructures and / or microstructures on a surface facing the functional layers. This enables a particularly clearly recognizable changed color impression because the functional layers enclose the nanostructures and / or microstructures of the carrier layer in the first state of the sealing element, or the elevations of the nanostructures and / or microstructures are embedded in at least one of the functional layers. The surface of the carrier layer facing away from the functional layers does not need to have any nanostructures and / or microstructures.

[0075] In the first state, the carrier layer appears transparent, although it is actually translucent, so that the surface of the sealing element in the first state is no different from that of a sealing element with a smooth carrier film. When the sealing element is now transferred from the first state to the second, i.e., when the carrier layer is peeled off from the remaining sealing element, the translucency of the carrier layer is only visible because the nanostructures and / or microstructures are exposed and diffusely reflect the light.

[0076] As a rule, after the carrier layer has been removed, the imprint of the nanostructures and / or microstructures in the functional layers can be seen, i.e. in the second state, a negative of the nanostructures and / or microstructures can be seen in the residue. In addition, the nanostructures and / or microstructures exposed after removal can also be perceived haptically. The nanostructures and / or microstructures created on the surface of the functional layer cause diffuse reflections on the surface of the functional layers, so that they appear matt. This means that both the nanostructures and / or microstructures on the surface of the carrier layer and the nanostructures and / or microstructures on the functional layers and / or the adhesive layer, but in particular the color representation layer, cause clouding. Together, this reinforces the color impression of the sealing element in the second state. This means thatWhen the peeled-off layer is applied to the residue, the sealing element appears cloudier in the areas that have been partially detached from the carrier layer, and colors appear paler and less intense. However, the peeled-off layer and the residue themselves also exhibit cloudiness. This results in even better security properties of the sealing element.

[0077] Particularly in cases where all functional layers are colorless and translucent, or even transparent, at least in a congruent surface area, preferably entirely, the negative of the nanostructures and / or microstructures in the residue creates a visible matting effect. This enables the production of discrete sealing elements with a particularly transparent appearance, in which a changed color impression is clearly visible both in the reattached state and in the residue alone.

[0078] Bonding the residue and the removed layer is made more difficult by the presence of nano- and / or microstructures. It is virtually impossible to reapply the removed layer to the residue with such precision that the nano- and / or microstructures interlock. This means that there will always be a gap between the carrier layer, once removed, and the residue, causing the light to be diffusely reflected due to the nano- and / or microstructures.

[0079] The security against tampering arises because the carrier layer or the removed layer can no longer be bonded to the residue as tightly after removal as occurs during the manufacturing process. As a result, the color of a color representation layer viewed through the removed layer no longer appears as intense as before tampering, i.e. the viewer now perceives the sealing element as more cloudy. In order to be able to recognize this color effect, the removed layer must be placed essentially congruently on the residue again. This is achieved by pressing the removed layer back onto the residue.

[0080] It may happen that, in this embodiment of the sealing element according to the invention, the carrier layer does not completely separate from the remaining sealing element as desired, but rather portions of the color representation layer still adhere. However, this does not affect the inventive effect in the other areas where the carrier layer has separated as desired.

[0081] According to the above statements, in a preferred embodiment of the invention it is provided that in the first state the nanostructures and / or microstructures of the carrier layer are pressed at least in regions (i.e. at least for a partial region of the carrier layer) completely or partially into the at least one color representation layer, so that in the second state a negative of the nanostructures and / or microstructures can be seen in the residue.

[0082] In a further embodiment of the invention, it is provided that the nanostructures and / or microstructures of the carrier layer are arranged at least in some areas (i.e. at least for a partial area of ​​the carrier layer) in such a way that they produce a diffractive image in the second state.

[0083] Such an arrangement enables a special security effect because the diffractive image is not visible in the first state of the sealing element. Only when the sealing element is converted into the second state by peeling off the carrier layer can the diffractive image on the side of the carrier layer facing the functional layers be recognized by an observer. This means that in the simplest case, an observer only sees a colored or colorless surface on the sealing element in the first state. However, if the sealing element is converted into the second state by at least partially peeling off the carrier layer, the observer can see a diffractive image of any desired design on the carrier layer, more precisely where the nano and / or microstructures are located. Bonding the peeled off layer and the residue is even more difficult in this case.

[0084] In order to achieve a particularly high level of security against tampering, an additional or alternative embodiment of the invention provides for a further diffractive image to be recognizable in the residue. In this case, too, the diffractive image only becomes visible when the sealing element is converted into the second state and is only recognizable if the removed layer is not reapplied to the residue. The fact that a further diffractive image can only be recognized in the residue can create an incentive to carefully remove the sealing element and check for the presence of the diffractive image.

[0085] This means that after the sealing element has been converted into the second state, a diffractive image is visible on the peeled-off layer, namely where the nano- and / or microstructures are arranged on the carrier layer, and a further diffractive image can be seen on the residue. The diffractive image on the residue is accordingly formed by the negative of the nano- and / or microstructures. The particularly high level of manipulation resistance results from the fact that even if the peeled-off layer is no longer arranged on the sealing element, a diffractive image and thus the conversion to the second state is clearly recognizable.

[0086] Such a diffractive element can be manufactured by pouring a molten plastic composition into a mold. The mold contains the negative of the desired micro- and / or nanostructure geometry, so that these are retained accordingly on the cured film. After pouring, the film hardens and can then be removed and cut to size as a carrier layer as desired. The diffractive element can also be manufactured using systematically arranged nanostructures and / or microstructures.

[0087] In one embodiment of the invention, the sealing element further comprises a second adhesion-controlling layer between the carrier layer and the adhesive layer in order to separate at least parts of the at least one color representation layer when the carrier layer is detached and to allow them to adhere to the carrier layer. With such a construction of the sealing element, at least one symbol is created when the carrier layer is detached, wherein at least one defined area is separated from the at least one color representation layer by the at least two adhesion-controlling layers, which area forms the at least one symbol. This means that the at least one symbol recognizable in the second state of the planar sealing element remains hidden from a viewer before the sealing element according to the invention is opened for the first time and is only optically visible after the opening.

[0088] When the carrier layer is now removed, the color representation layer is separated from the carrier layer, or from the carrier layer in certain areas, and the desired symbol becomes visible. At least one symbol can then be visible in the second state on the removed layer and / or on the residue.

[0089] If the flat sealing element comprises additional color-representation layers and / or adhesion-controlling layers, the removed layer can be formed by the carrier layer and parts or entire additional functional layers. In the simplest case, the residue consists only of the adhesive layer and parts of a color-representation layer. If a sealing element has additional functional layers, the residue can also comprise additional layers or parts of layers.

[0090] In a further embodiment of the invention, it is provided that in the first state the nanostructures and / or microstructures of the carrier layer are pressed wholly or partly at least in regions (i.e. at least for a partial region of the carrier layer) into the one color representation layer and at least one further functional layer, so that in the second state a negative of the nanostructures and / or microstructures can be seen in the functional layers of the residue (i.e. for example in the color representation layer and the at least one further functional layer of the residue).

[0091] Because the nano- and / or microstructures are pressed not only into the uppermost functional layer, but also into those further below, an even stronger color effect is achieved when several adhesion-controlling layers separate the functional layers at different levels. This means that the color difference is even more pronounced for an observer in the first and second states of the sealing element due to the different surface structuring.

[0092] The negative of the nano- and / or microstructures of the carrier layer will be most pronounced in the uppermost functional layer, which is closest to the nano- and / or microstructures, i.e. will have the greatest depth, and will be increasingly less pronounced, i.e. less deep, in the following functional layers.

[0093] Such a sealing element structure also makes it possible to create complex security features such as multicolored symbols or three-dimensional symbols that are only visible when the sealing element is transferred to the second state. The advantage of this is that only one color representation layer is required, and the varying thicknesses of this layer allow for different color gradations to be visible.

[0094] Due to the different transfer depths of the reliefs from nano- and / or microstructures, the symbol contrast is visible even when the color representation layers, which are separated by the adhesion-controlling layers, are transparent. For embodiments where a negative of the nano- and / or microstructures remains in at least one translucent (in particular transparent), preferably additionally colorless functional layer of the residue, a metallic layer can be provided between this functional layer and the adhesive layer. This metallic layer increases the visibility of the nano- and / or microstructures in the residue as soon as the sealing element has been opened, i.e., has been placed in the second state.

[0095] According to one embodiment of the invention, the carrier layer has nanostructures and / or microstructures both on a surface facing away from the functional layers and on a surface facing the functional layers. By arranging nanostructures and / or microstructures on both sides, the effects of the embodiment with only nanostructures and / or microstructures on the surface facing away from the functional layers (and no nanostructures and / or microstructures on the surface facing the functional layers) and the embodiment with only nanostructures and / or microstructures on the surface facing the functional layers (and no nanostructures and / or microstructures on the surface facing away from the functional layers) can be combined.

[0096] In general, by arranging several color display layers and adhesion control layers accordingly, several symbols can be displayed simultaneously in several differently colored sub-areas.

[0097] It can thus be provided that the separated, defined area visible in the second state, i.e. the at least one symbol of the at least one color representation layer does not adhere directly to the carrier layer or to the adhesive layer, but can also adhere indirectly via one or more further functional layers arranged on the carrier layer or on the adhesive layer.

[0098] The functional layers produce something visually perceptible, e.g., a color or a code, or an effect is created, for example, by means of adhesion-controlling layers. This means that "functional layers" is the umbrella term for, for example, color representation layers and adhesion-controlling layers. However, the term functional layers can also refer to additional color representation layers, additional adhesion-controlling layers, or merely intermediate layers, such as fill layers. Of course, it is also possible that the functional layers are merely transparent.

[0099] The color representation layers, in turn, can comprise one or more buildup layers. This means that, depending on the color of a color representation layer, the color representation layer comprises one or more buildup layers, or a photographic image obtained from multiple layers or from screened colors. In particular, a color representation layer can contain a metallic layer that is, for example, vapor-deposited onto another functional layer.

[0100] It would be conceivable that the functional layers are preferably applied to one another using flexographic printing, screen printing, letterpress printing, gravure printing, offset printing or digital printing processes.

[0101] Only when the carrier layer is removed, i.e. when the surface is converted into a second state, does either a different color impression or even a symbol become visible. This means that in a first state of the flat sealing element, the color impression is different or that at least one symbol is not recognizable to an observer, but the sealing element always appears as a single-colored surface or as a multi-colored printed surface. However, the coloring or the lightening in the second state or the hidden symbols are unrecognizable.

[0102] The individual color representation layers can have different or identical colors; they can be opaque, semi-opaque, translucent, or transparent. A color representation layer could consist of sections of different colors, which could be arranged, for example, in stripes or grids, or in the form of images and / or patterns. A special case of the color representation layer contains no color particles and therefore appears colorless.

[0103] Furthermore, it is not excluded that the flat sealing element further comprises a code, wherein the code is part of the sealing element, preferably part of the functional layers arranged between the carrier layer and the adhesive layer, and / or part of the adhesive layer. A (further) code could otherwise also be located directly on the substrate, e.g., the packaging, and be visible through the sealing element or only become visible in the second state of the sealing element.

[0104] If it is to be prevented that the code cannot be read when it has not been removed, at least one of the color display layers can be opaque or contain an interference pattern, or the code can not stand out visually for other reasons, or the plastic of the carrier layer can have an opaque coating in surface areas, or the colored adhesive layer covers the code on a package.

[0105] In order to provide flat sealing elements that can be used as flexibly as possible, one embodiment of the invention provides for the sealing element to be a label. Labels are understood, in particular, to be adhesive labels used to secure valuables and their packaging, or to conceal codes or barcodes, or as carriers of forgery-proof security features.

[0106] To allow the user to determine the size of the sealing element themselves depending on the application, one embodiment of the invention provides for the flat sealing element to be an adhesive tape. An adhesive tape makes it possible to apply larger or longer sealing elements to a valuable object or its packaging, thereby making unnoticed tampering with the security even more difficult.

[0107] To enable a flat sealing element in the form of an adhesive tape to be rolled up, one embodiment of the invention provides that the sealing element further comprises a silicone-containing layer on the carrier layer on the side facing away from the functional layers. The presence of the silicone-containing layer makes it possible to roll up the adhesive tape onto a roll, since the silicone-containing layer prevents the outer side of the adhesive layer from adhering to the outer side of the carrier layer. Rolling up enables better and more space-saving storage.

[0108] In order to enable storage of the flat sealing element before use without reducing the adhesive properties of the adhesive layer, one embodiment of the invention provides that a siliconized cover layer made of paper or plastic is arranged on the adhesive layer on the side facing away from the functional layers to protect the adhesive layer.

[0109] This cover layer prevents the flat sealing element from sticking to any surface during storage, i.e., prior to use as a security measure. Such sticking could even render the flat sealing element unusable in the case of strong adhesion, because it can no longer be removed from the surface without impairing its function.

[0110] In order to be able to provide a particularly easily removable temporary cover of the adhesive layer, one embodiment of the invention provides that the cover layer is made of siliconized highly calendered paper or of siliconized polyethylene terephthalate.

[0111] Also provided is a system comprising a flat sealing element and a packaging object for goods. The sealing element corresponds to a sealing element as described in the embodiments of claims 1 to 20. The substrate mentioned in claims 1 to 20 is thus the packaging object.

[0112] Packaging for goods is particularly considered to be packaging made of paper, cardboard, carton, corrugated cardboard, metal, glass, composites or plastic that is suitable for packaging different types of goods. Examples of this include packaging for sensitive goods such as pharmaceuticals or technical devices, for which labelling and sealing are particularly important. However, other types of packaging or goods are of course not excluded. The flat sealing element could be used to indicate the opening of the packaging object and / or to securely attach counterfeit-proof features or object identification codes.

[0113] In one embodiment of the system, the invention provides that the functional layers and / or the adhesive layer are transparent or translucent in a congruent surface area, so that the recognition of information for goods applied beneath the adhesive layer on the surface of the packaging object is possible at least in a partial area. The information can therefore be recognized in the first state of the sealing element. Opening the sealing element is not necessary in order to be able to read the information. On the other hand, readability is also not impaired, or not significantly impaired, by opening or detaching the sealing element. This recognition and reading can take place with the naked eye of an observer or with machine assistance.

[0114] In another embodiment of the invention, it is provided that the functional layers and / or the adhesive layer have an opacity at least in a congruent surface area, so that the recognition of information for goods applied under the adhesive layer on the surface of the packaging object is not possible at least in a partial area.

[0115] SHORT DESCRIPTION OF THE CHARACTERS

[0116] The invention will now be explained in more detail using an exemplary embodiment. The drawings are exemplary and are intended to illustrate the inventive concept, but in no way restrict it or represent it exhaustively.

[0117] It shows:

[0118] Fig. 1 shows the schematic structure of a sealing element according to the invention with two adhesion-controlling layers;

[0119] Fig. 2A shows the first state of the flat sealing element of Fig. 1; Fig. 2B shows the second state of the flat

[0120] Sealing element of Fig. 1

[0121] Fig. 3 shows the second state of a planar sealing element according to the invention, wherein the nano- and / or microstructures are visible.

[0122] WAYS OF IMPLEMENTING THE INVENTION

[0123] Fig. 1 shows the roughly schematic structure of an embodiment of a flat sealing element 1 according to the invention, in which all successive layers are shown one below the other as an exploded view. The structure of a sealing element 1 according to the invention is described below in a first direction 25, beginning from the carrier layer 3 in the direction of the adhesive layer 8.

[0124] In general, it should be noted at this point that the layers or layer thicknesses as well as the nano- and / or microstructure shown in the figures do not correspond to the original size, but are shown greatly enlarged for illustrative purposes, if they are shown at all.

[0125] Viewed in the first direction 25, the adhesive layer 8 is the layer furthest away from the carrier layer 3, i.e. all functional layers 4 are arranged between the carrier layer 3 and the adhesive layer 8.

[0126] Viewed in a first direction 25, the carrier layer 3 serves as a color representation layer due to its matte appearance. The carrier layer 3 obtains this matte appearance, i.e. its cloudiness, from nano- and / or microstructures 13 present on a surface (not shown, see Fig. 3). These nano- and / or microstructures 13 cause a diffuse scattering of the light, as a result of which the carrier layer 3 appears cloudy. In the present embodiment of the invention, the nano- and / or microstructures 13 are arranged on the surface facing the functional layers 4. Of course, the nanostructures and / or microstructures 13 could also be present on the surface facing away from the functional layers 4 or on both surfaces.

[0127] The positive image of a V, which in the present embodiment of the sealing element 1 represents at least one symbol 18, is then applied to the carrier layer 3 or to the surface with the nanostructures and / or microstructures 13. The symbol 18 is applied as the first adhesion-controlling layer 6. In the present case, the adhesion-controlling layer 6 is a transparent release varnish with at least one silicone and / or at least one wax. The first adhesion-controlling layer 6 has the effect of reducing the surface tension, so that adjacent functional layers 4, in the present case the color representation layer 5, adhere less or not at all.

[0128] An intermediate layer 24 is further arranged on this adhesion-promoting, adhesion-controlling layer 6. This intermediate layer 24 is optional and therefore does not necessarily have to be present in every embodiment of the invention. The color representation layer 5 is then arranged as a further layer, the next functional layer 4, below the carrier layer 3.

[0129] Since the first adhesion-controlling layer 6 was applied only in the region of the symbol 18, i.e., the V, the color representation layer 5 and the intermediate layer 24 bond inseparably to the carrier layer 3 outside the V. These layers can subsequently no longer be separated from one another. In the region of the first adhesion-controlling layer 6, the layers 5, 24 bond to the carrier layer 3 only in a slightly detachable manner.

[0130] Next, the negative of the symbol 18, i.e., the V, is arranged as a further adhesion-controlling layer 7 on the color representation layer 5. Further layers may be present, such as further color representation layers and further adhesion-controlling layers.

[0131] Therefore, an additional color representation layer 17 can optionally be present beneath the adhesion-controlling layer 7 in order to obtain a particular color effect in the residue 12 (see Fig. 2) and / or to separate the additional color representation layer 17 from the adhesive layer 8 if no additional carrier layer 26 is present. An optional additional carrier layer 26 could also separate the adhesion-controlling layer 7 from the adhesive layer 8 if no additional color representation layer 17 is present.

[0132] Finally, the adhesive layer 8 is arranged.

[0133] The functional layers 4 are thus only partially inseparably connected to one another, while others or parts of functional layers 4 are only easily detachably connected to one another, namely where the two adhesion-controlling layers 6, 7 are located. The carrier layer 3 of the flat sealing element is made of polypropylene in this case, wherein the side facing the functional layers 4 was provided with nano- and / or microstructures during the production of the smooth polypropylene film. In the present case, this was achieved by embossing the nano- and / or microstructures 13 into a lacquer layer of the carrier layer 3 itself.

[0134] The substrate 2 (see Fig. 2) can be plastic, paper, cardboard, corrugated cardboard, metal, glass, or composites. If the substrate 2 is made of plastic, it is advantageous if it is also made of polypropylene or polyethylene, because then the flat sealing element 1 can be recycled together with the substrate 2 without significantly negatively impacting the recycled material.

[0135] The color representation layer 5 of the functional layers 4 is a commercially available printing ink or a commercially available varnish (UV-curing, solvent-based, or water-based varnish), which can also additionally contain a vapor-deposited metal layer, and the adhesion-controlling layers 6, 7 are a so-called transparent release varnish that comprises at least one silicone and / or at least one wax. However, a colorant and / or pigment can also be added to the release varnish, which is visible at different wavelengths or can be made visible with the aid of technical devices (e.g., UV lamp, IR lamp, etc.).

[0136] The adhesive layer 8 comprises a commercially available adhesive composition. In the present case, this is an acrylic-based or rubber-based pressure-sensitive adhesive, which can, for example, be dispersed, dissolved in a solvent, or applied as a rubber-based hot-melt adhesive or UV-curing hot-melt acrylate. Alternatively, a heat-seal adhesive could also be used to create a solid bond between the sealing element 1 and the surface of the substrate 2. The adhesive layer 8 serves to attach the flat sealing element 1 to any substrate 2. Preferably, the adhesion by means of the adhesive layer 8 to the substrate 2 of the sealing element 1 according to the invention is so strong that the sealing element 1 can only be detached from the substrate 2 by applying force.Instead of the first adhesion-controlling layer 6, however, the carrier layer 3 could have, at least in sections, a specific surface quality which reduces the surface tension per se, thereby preventing the functional layers 4 from adhering to the carrier layer 3.

[0137] In addition, the sealing element 1 can also comprise a siliconized cover layer on the side of the adhesive layer 8 facing away from the functional layers 4. However, the presence of such a siliconized cover layer is not mandatory. The siliconized cover layer can be made of siliconized, highly calendered paper or polyethylene terephthalate in order to enable the winding up of a sealing element 1. At the same time, the siliconized cover layer acts as a carrier for the sealing element 1 before it is adhered to the object to be sealed. In other words, the siliconized cover layer enables the storage and delivery of the sealing element in a first state.

[0138] Fig. 2 shows that the planar sealing element 1 according to the invention according to Fig. 1 is converted from a first state 9, see Fig. 2A, into a second state 10, see Fig. 2B. In the first state 9, the sealing element 1 according to the invention is glued to a substrate 2 and closed, i.e. it has not been tampered with and the symbol 18 is not recognizable to an observer. To an observer looking at the carrier layer 3 from the outside, the sealing element 1 therefore appears dark blue in its entirety, for example. Of course, it is not excluded that the sealing element 1 according to the invention in the first state 9 as well as in the second state 10 has other colors or color combinations or a metallic appearance due to a metal layer within or as part of a color representation layer 5. Furthermore, the sealing element 1 could also be completely colorless.

[0139] The nano- and / or microstructures 13 are transferred into the functional layers 4, wherein the depth of the transferred nano- and / or microstructures 13 decreases with increasing distance from the carrier layer 3. If, for example, two adhesion-controlling layers 6, 7 are used to dissolve a symbol 18 when converting from the first state 9 to the second state 10, then the nano- and / or microstructures 13 are transferred into the color representation layer 5 and the second adhesion-controlling layer 7 as a negative, to a greater extent into the color representation layer 5, which is arranged closer to the carrier layer 3, than into the subsequent second adhesion-controlling layer 7, which is correspondingly further away from the carrier layer 3.The varying degrees of negatives of the nano- and / or microstructures 13, due to the different distances between the individual layers and the carrier layer 3, lead to different reflections in the residue 12, resulting in different color impressions. However, the nano- and / or microstructures 13 can, in principle, also be transferred into the adhesive layer 8.

[0140] The carrier layer 3 has, on the surface facing the functional layers 4, nano- and / or microstructures 13 which, during production, are pressed into the functional layers 4 adjacent to this carrier layer 3. This pressing into the functional layers 4 is a consequence of the manufacturing process of the sealing element 1, in which production takes place layer by layer. The further the nano- and / or microstructures 13 protrude from the carrier layer 3 and the thinner the individual functional layers 4 are, the further the nano- and / or microstructures 13 are pressed into the adjacent functional layers 4. In the first state 9, the nano- and / or microstructures 13 of the carrier layer 3 are embedded or pressed into the adjacent intermediate layer 24 or the color representation layer 5. The nano- and / or microstructures 13 cannot therefore be detected and cannot fulfill their function, namely the creation of opacity.The sealing element 1 therefore appears considerably less cloudy in the first state 9 than in the second state 10 .

[0141] In principle, the nano- and / or microstructures 13 could also be present on the surface of the carrier layer 3 that faces away from the functional layers 4. In this case, the nano- and / or microstructures 13 are accordingly not embedded in the functional layers 4 in the first state 9. Furthermore, the nano- and / or microstructures 13 can also be present on both surfaces of the carrier layer 3, i.e., the surface facing the functional layers 4 and the surface facing away from the functional layers 4.

[0142] The sealing element 1 according to the invention is converted into a second state 10 by opening, see Fig. 2B. In the second state 10, both a residue 12 and an at least partially removed layer 11 are visible.

[0143] The residue 12 comprises the parts of the functional layers 4 and the adhesive layer 8 remaining on the substrate 2. The peeled-off layer 11 comprises the at least partially detached parts of the functional layers 4 and the carrier layer 3.

[0144] Because the nano- and / or microstructures 13 of the carrier layer 3 have been pressed into the adjacent functional layers 4 during the manufacturing process, a negative of the micro- and nanostructures 13 is present in the uppermost of these functional layers 4, in particular the color representation layer 5 closest to the carrier layer 3. Both the nano- and / or microstructures 13 in the carrier layer 3 and the nano- and / or microstructures 13 of the functional layers 4 formed thereby cause a diffuse reflection of the incident light, as a result of which both the peeled-off layer 11 and the residue 12 appear cloudy. The color effect is accordingly clearly visible.

[0145] As a result of the at least partial detachment of functional layers 4, the symbol 18 is now visible in the residue 12 or the peeled-off layer 11 due to the two adhesion-controlling layers 6, 7, which ensure an only easily detachable connection between the color representation layer 5 and the positive of the symbol 18, i.e. the V in the present case, as well as the carrier layer 3. This means that the first release lacquer layer 6 separates the carrier layer 3 and the color representation layer 5 from one another and ensures the color formation of the symbol 18. In the residue 12, the, for example, dark blue color representation layer can be seen as the positive of the symbol 18, which is now an even more intense dark blue, while the peeled-off layer 11 appears matt white in the area of ​​the symbol 18 and outside the symbol 18 the dark blue appears lighter than in the first state 9. It goes without saying that the symbol 18 can in principle have any desired shape.even several symbols 18 can be combined with each other.

[0146] However, the nano- and / or microstructures 13 also make it impossible to reapply the removed layer 11 to the residue 12 without being noticed. Manipulation is thus virtually impossible.

[0147] As already mentioned, it is not absolutely necessary for the adhesion-controlling layer 6 to be such. Instead of the adhesion-controlling layer 6, at least the surface of the carrier layer 3 facing the functional layers 4 could have a special surface quality which causes a low surface tension, so that permanent adhesion of the functional layers 4 to the carrier layer 3 is prevented. When a force is applied, when the carrier layer 3 is detached from the residue 12, the sealing element 1 would then also be able to be converted from a first state 9 into a second state 10, just as when an adhesion-controlling layer 6 is present. The creation of a symbol is not excluded even with carrier layers 3 with low surface tension. Here, an adhesion-controlling layer 6 is also used, which enables the carrier layer 3 to be printed on at the location of the symbol 18, i.e.increases the surface tension. Such adhesion-controlling layers that increase the surface tension are known to those skilled in the art.

[0148] If the peeled-off layer 11 were placed back onto the residue 12 so that it was congruent, the residue 12 would appear a lighter, dark blue when viewed through the symbol 18 of the peeled-off layer 11. This is due to the now clearly visible turbidity of the peeled-off layer 11 and the residue 12, which is each created by the now exposed nano- and / or microstructures 13. These diffusely scatter the incident light, which is why turbidity can be detected.

[0149] The sealing element 1 according to the invention does not necessarily have to have an opaque dark blue color representation layer 5 as in the previously mentioned example. Alternatively, the color representation layer 5 or, if appropriate, the color representation layers 5, 17 could also be transparent or translucent. It is also possible for the color representation layers 5, 17 to be colored transparent or colorlessly transparent. A changed color impression can also be determined when measuring these flat sealing elements 1, which can also be determined by means of a Delta E measurement. If the only color representation layer 5 is colorlessly transparent, this is the simplest possible embodiment of the present invention.

[0150] If it is desired that the peeled-off layer 11 does not separate completely from the rest of the flat sealing element 1, an area can be provided at the edge of the sealing element 1 in which area no adhesion-controlling layer 6, 7 is applied, so that the color representation layer 5 is inseparably bonded to the carrier layer 3. Complete removal of the peeled-off layer 11 is therefore only possible by applying greater force. The peeled-off layer 11 thus remains on the flat sealing element 1. This reduces the loss of the sealing element into the environment. The sealing element 1 can therefore also be recycled or reused as a material.

[0151] Furthermore, it would be conceivable for the flat sealing element 1 according to the invention to have a tab (not shown) which is connected to the carrier layer 3. Said tab makes it easier for a user to peel off the carrier layer 3 or to transfer the sealing film 1 according to the invention from the first state 9 to the second state 10.

[0152] Fig. 3 also shows an embodiment of a sealing element 1 according to the invention. The sealing element 1 is shown in the second state 10, as in the embodiment of Fig. 2B. In the present case, the carrier layer 3 has an additional lacquer layer or polymer layer, the surface of which contains the nanostructures and / or microstructures 13.

[0153] The sealing element 1 according to the embodiment of Fig. 3 has a peeled-off layer 11 and a residue 12. The peeled-off layer 11 comprises the carrier layer 3, the first color representation layer 5 and parts of the first adhesion-controlling layer 6 (see Fig. 1), the first adhesion-controlling layer 6 being applied only in the region of a symbol 18 formed as a rectangle and being arranged below the symbol 18 in Fig. 3. It is clearly visible that the color representation layer 5 has nano- and / or microstructures 13. The second adhesion-controlling layer 7 also has nano- and / or microstructures 13, these nano- and / or microstructures 13 being less pronounced than those on the upper side of the first color representation layer 5.This results from the fact that in the manufacturing process the first adhesion-controlling layer 6 is first applied and then the first color representation layer 5 is applied over it, and only then the second adhesion-controlling layer 7.

[0154] The residue 12 comprises the second adhesion-controlling layer 7 and the adhesive layer 8, as well as parts of the color representation layer 5. As can be clearly seen, the second adhesion-controlling layer 7 is arranged only in the area around the rectangular symbol 18. This arrangement of the two adhesion-controlling layers 6, 7 makes it possible to display the symbol 18 in the second state.

[0155] From Fig. 3 it can be seen that in the area where the peeled layer 11 has already been peeled off from the residue 12, nano- and / or microstructures 13 are also present. These nano- and / or microstructures 13 are a negative of the nano- and / or microstructures 13 of the carrier layer 3 or of the first color representation layer 5 (into which the nano- and / or microstructures 13 of the carrier layer 3 have been imprinted), which nano- and / or microstructures 13 are now also recognizable in an attenuated form on the second adhesion-controlling layer 7 around the symbol 18 in the residue 12. In the area of ​​the symbol 18 in the residue 12, the negative of the nano- and / or microstructures 13 is recognizable in a non-attenuated form, because there was previously direct contact with the carrier layer 3. The advantage of this is that in the residue

[0156] 12 by the presence of nano- and / or microstructures

[0157] 13 both on the first color representation layer 5 (in symbol 18) and on the second adhesion-controlling layer 7 (around symbol 18) the haze is increased because the presence of the nano- and / or microstructures 13 leads to diffuse reflection. The exposed nano- and / or microstructures 13 of the carrier layer 3 in symbol 18 in the peeled-off layer 11 also cause strong haze, while the nano- and / or microstructures 13 present in a weakened form on the underside of the peeled-off layer 11 in the color representation layer 5 also cause haze, albeit to a lesser extent.

[0158] In the embodiment of Fig. 3, it is also evident that the nano- and / or microstructures 13 are more pronounced in the area of ​​the black rectangle than in the surrounding white area. This achieves a further color effect and enhances the symbol contrast.

[0159] Sealing elements 1 according to the embodiment of Fig. 3 or sealing elements 1 according to the invention which correspond to Fig. 3 with the difference that the nano- and / or microstructures 13 are arranged on the surface of the carrier layer 3 facing away from the functional layers 4, were measured and compared with sealing elements known from the prior art, it being found that the color effect is significantly more recognizable with the sealing elements 1 according to the invention than with those of the prior art. To compare the sealing elements, the Delta E value (AE) was measured in the first state 9 and then in the second state 10. These measurements were carried out once against a white background and once against a black background.

[0160] The sealing element known from the prior art did not have any nano- and / or microstructures 13. Furthermore, for the sealing elements 1 according to the invention, one variant with an opaque color representation layer 5, one with a translucent color representation layer 5, and one with a transparent color representation layer 5 were each measured.

[0161] A Delta E value was obtained for each measurement. The Delta E values ​​obtained from the measurement in the second state were subsequently compared, with the counterpart of the sealing element from the prior art being compared with the one according to the invention.

[0162] Example 1 - Opaque sealing element with nano- and / or microstructures on the side facing the functional layers; measured on a white background

[0163] First, it was determined by how much more perceptible the effect is with the sealing elements 1 according to the invention than with one known from the prior art. For this purpose, the sealing element in the first state 9 was measured as a reference for the Delta E measurements. As a second reference value, the measurement was carried out in the area of ​​the adhesion-controlling layer in the second state 10. This showed that for all of the sealing elements 1 measured, the sealing elements 1 according to the invention have a significantly more pronounced color effect than the sealing elements known from the prior art.

[0164] For example, in a sealing element 1 according to the invention with opaque color representation layers 5, wherein the nanostructures and / or microstructures are arranged on the surface facing the functional layers 4, an approximately 4 times better effect was observed in the region of the adhesion-controlling layer 6 than in a sealing element with opaque color representation layers known from the prior art. The measurement was carried out on a white background.

[0165] In addition, a comparison of the color contrasts (or the symbol contrast) of sealing elements known from the prior art and sealing elements 1 according to the invention was determined by calculating the difference between measured Delta E values ​​in the region of the first adhesion-controlling layer 6 and in the region of the second adhesion-controlling layer 7, with the first state 9 of that sealing element 1 being used as the reference value. Such a comparison also shows that the color contrast between the two adhesion-controlling layers 6, 7 is considerably more pronounced in a sealing element 1 according to the invention. Thus, in a sealing element 1 according to the invention according to this example, a contrast between the symbols is perceived to be approximately 60 times stronger. The measurement was carried out on a white background.

[0166] Example 2 - Translucent sealing element with nano- and / or microstructures on the side facing the functional layers; measured on a black background

[0167] Furthermore, a sealing element 1 according to the invention was also measured, in which the nanostructures and / or microstructures 13 are arranged on the surface of the carrier layer 3 facing the functional layers 4, with translucent color layers. In the region of the first adhesion-controlling layer 6, a color effect approximately 18 times better than that of a comparable sealing element from the prior art could be measured. The measurement was performed on a black background.

[0168] When comparing the Delta E values ​​in the area of ​​the first adhesion-controlling layer 6 and the second adhesion-controlling layer 7 to determine the color contrast, a color contrast approximately 70 times better than that measured in comparison to sealing elements of the prior art was obtained.

[0169] Example 3 - Transparent sealing element with nano- and / or microstructures on the side facing the functional layers; measured on a black background

[0170] Furthermore, a sealing element 1 according to the invention was also measured, in which the nanostructures and / or microstructures 13 are arranged on the surface of the carrier layer 3 facing the functional layers 4, with transparent color layers. In the region of the first adhesion-controlling layer 6, a color effect approximately 12 times better than that of a comparable sealing element from the prior art could be measured. The measurement was performed on a black background.

[0171] When comparing the Delta E values ​​in the area of ​​the first adhesion-controlling layer 6 and the second adhesion-controlling layer 7 to determine the symbol contrast, a color contrast approximately 130 times better than that measured in comparison to sealing elements of the prior art was obtained.

[0172] Example 4 - Opaque sealing element with nanostructures and / or microstructures on the side facing away from the functional layers; measured on a white background. In addition, a sealing element 1 according to the invention was also measured, in which the nanostructures and / or microstructures 13 are arranged on the surface of the carrier layer 3 facing away from the functional layers 4, with translucent color layers, in which a color effect approximately 1.8 times better than a comparable sealing element from the prior art can be measured in the region of the first adhesion-controlling layer 6. The measurement was carried out on a white background.

[0173] When comparing the Delta E values ​​in the area of ​​the first adhesion-controlling layer 6 and the second adhesion-controlling layer 7 to determine the symbol contrast, a color contrast approximately 20 times better than that measured in comparison to sealing elements of the prior art was obtained.

[0174] Example 5 - Comparison of an opaque sealing element with nano- and / or microstructures on the side facing away from the functional layers and an opaque sealing element with nano- and / or microstructures on the side facing the functional layers;

[0175] In addition, a comparison was made between the symbol contrast generated by sealing elements 1 according to the invention, in which the nanostructures and / or microstructures 13 are arranged on the surface of the carrier layer facing away from the functional layers, and sealing elements 1 according to the invention in which the nanostructures and / or microstructures 3 are arranged on the surface of the carrier layer facing the functional layers. For this purpose, the ratio between the symbol contrasts of the two sealing elements 1 was used.

[0176] In the case of sealing elements according to the invention in which the nano- and / or microstructures 3 are arranged on the surface of the carrier layer facing the color layers and are fastened to a white background, the symbol contrast is approximately 2.5 times higher with an opaque color layer, approximately 1.5 times higher with a translucent color layer and approximately 3.5 times higher with a transparent color layer than in the case of sealing elements according to the invention which are fastened to the same white background and in which the nano- and / or microstructures 13 are arranged on the surface of the carrier layer 3 facing away from the functional layers.

[0177] In the case of sealing elements according to the invention in which the nano- and / or microstructures 13 are arranged on the surface of the carrier layer 3 facing the functional layers and which are fastened to a black background, the symbol contrast is approximately 40 times higher with an opaque color layer, approximately 10 times higher with a translucent color layer and approximately 5 times higher with a transparent color layer than in the case of sealing elements according to the invention which are fastened to the same black background and in which the nano- and / or microstructures 13 are arranged on the surface of the carrier layer 3 facing away from the color layers.

[0178] LIST OF REFERENCE SYMBOLS

[0179] 1 flat sealing element

[0180] 2 Underground

[0181] 3 Carrier layer

[0182] 4 functional layers

[0183] 5 Color representation layer

[0184] 6 first liability-controlling layer

[0185] 7 second liability-controlling layer

[0186] 8 Adhesive layer

[0187] 9 first state of the flat sealing element second state of the flat sealing element peeled layer

[0188] residue

[0189] Nanostructures and / or microstructures additional color representation layer

[0190] symbol

[0191] Intermediate layer first direction further carrier layer

Claims

A N S P R Ü C H E 1. A planar sealing element (1) for application to a substrate (2), comprising a carrier layer (3) and at least one, preferably several, functional layer(s) (4), wherein the at least one functional layer (4) is a color representation layer (5), wherein the sealing element (1) further comprises an adhesive layer (8) for attachment to the substrate (2), wherein the at least one functional layer (4) is arranged between the carrier layer (3) and the adhesive layer (8), wherein the carrier layer (3) has a surface finish and / or the carrier layer (3) further comprises an adhesion-controlling layer (6) as a further functional layer (4), so that the carrier layer (3) is at least partially detachable from the at least one functional layer (4) in order to bring the sealing element (1) from a first state (9) into a second state (10), wherein the second state (10) cannot be converted into the first state (9),wherein the sealing element (1) in the second state (10) comprises a peeled-off layer (11), comprising at least the at least partially detached carrier layer (3), and a residue (12), comprising at least parts of the adhesive layer (8) and at least parts of the at least one color representation layer (5), and wherein the carrier layer (3) is made of a translucent or transparent plastic, characterized in that the carrier layer (3) has nanostructures and / or microstructures (13) at least on one of its surfaces, wherein the peeled-off layer (11) in at least one area in which no or, only small portions of the at least one color representation layer (5) adhere when the peeled-off layer (11) is arranged congruently on the residue (12), due to diffuse reflection by the nanostructures and / or microstructures (13) has a different color impression than the same area of ​​the carrier layer (3) in the first state (9) in a viewing direction onto the carrier layer (3).

2. Flat sealing element (1) according to claim 1, characterized in that at least in some areas there are systematically arranged, in particular regular, nanostructures and / or microstructures (13).

3. Flat sealing element (1) according to claim 2, characterized in that the nanostructures and / or microstructures (13) are preferably embossed on a lacquer layer, in particular a UV-cured lacquer layer, arranged at least in sections on a surface of the carrier layer (3).

4. Flat sealing element (1) according to one of the preceding claims, characterized in that at least in some areas randomly arranged nanostructures and / or microstructures are present.

5. Flat sealing element (1) according to one of the preceding claims, characterized in that the nanostructures and / or microstructures measured in the plane of the sealing element (1) have a size of 50 nm to 200 pm, preferably 60 nm to 100 pm, particularly preferably 100 nm to 60 pm, in particular 500 nm to 60 pm.

6. Flat sealing element (1) according to one of the preceding claims, characterized in that the nanostructures and / or microstructures are normal to the plane of the sealing element (1) have a size of more than 50 nm, preferably from 2 pm to 100 pm, particularly preferably from 3 gm to 50 gm.

7. Flat sealing element (1) according to one of the preceding claims, characterized in that the carrier layer (3) has a turbidity in the range of 30 to 100%, preferably 70 to 80%.

8. Flat sealing element (1) according to one of the preceding claims, characterized in that all layers are at least translucent at least in a congruent surface area.

9. Flat sealing element (1) according to claim 8, characterized in that all layers are colorless at least in a congruent surface area.

10. Flat sealing element (1) according to one of the preceding claims, characterized in that at least one functional layer (4) is opaque at least in one surface area.

11. Flat sealing element (1) according to claim 10, characterized in that a metallic layer is part of at least one functional layer (4).

12. Flat sealing element (1) according to one of the preceding claims, characterized in that a further carrier layer is additionally arranged between a functional layer (4) and the adhesive layer (8) or between two functional layers (4).

13. Flat sealing element (1) according to one of the preceding claims, characterized in that the carrier layer (3) has nanostructures and / or microstructures on a surface facing away from the functional layers (4).

14. Flat sealing element (1) according to one of the preceding claims, characterized in that the carrier layer (3) has nanostructures and / or microstructures on a surface facing the functional layers (4).

15. Flat sealing element (1) according to claim 14, characterized in that in the first state (9) the nanostructures and / or microstructures of the carrier layer (3) are at least partially pressed into the at least one color representation layer (5) in whole or in part, so that in the second state (10) a negative of the nanostructures and / or microstructures can be seen in the residue (12).

16. Flat sealing element (1) according to claim 14 or 15, characterized in that the nanostructures and / or microstructures of the carrier layer (3) are arranged at least in regions such that they produce a diffractive image in the second state.

17. Flat sealing element (1) according to claim 16, characterized in that a diffractive image is further recognizable in the residue (12).

18. Flat sealing element (1) according to one of the preceding claims, characterized in that the sealing element (1) further comprises a second adhesion-controlling layer (7) between the carrier layer (3) and the adhesive layer (8) in order to Detaching the carrier layer (3) to separate out at least parts of the at least one color representation layer (5) and to allow them to adhere to the carrier layer (3).

19. Flat sealing element (1) according to one of claims 14 to 18, characterized in that in first state (9) the nanostructures and / or microstructures of the carrier layer (3) are pressed at least partially into the one color representation layer (5) and at least one further functional layer (4), so that in the second state (10) a negative of the nanostructures and / or microstructures in the color representation layer (5) and the at least one further functional layer (4) of the residue (12) is recognizable.

20. Flat sealing element (1) according to claim 13 and 14, characterized in that the carrier layer (3) has nanostructures and / or microstructures both on a surface facing away from the functional layers (4) and on a surface facing the functional layers (4).

Images