EP1966338A1

EP1966338A1 - Label with improved antiforgery security

Info

Publication number: EP1966338A1
Application number: EP06819899A
Authority: EP
Inventors: Arne Koops; Sven Reiter
Original assignee: Tesa SE
Current assignee: Tesa SE
Priority date: 2005-12-19
Filing date: 2006-12-04
Publication date: 2008-09-10
Also published as: WO2007071546A1; US20080290648A1; JP2009520222A; CN101331201A; KR20080078715A; DE102005061124A1

Abstract

The invention relates to a label with improved antiforgery security, comprising an adhesive layer applied to the lower face of the support layer. The invention in is characterized in that in or on the bare face of the adhesive layer a plurality of discrete inclusions are present which contain at least one reversibly detective additive. When the label is bonded to a base, the discrete inclusions are forced into the adhesive mass to such a degree that the layers of the label present above the inclusions are deformed, thereby forming haptically distinguishable and optically visible bumps in the surface of the upper support layer.

Description

description

Label with increased counterfeit security

The invention relates to a label with increased security against forgery from a carrier layer, in particular lacquer layer, very particularly from duroplastic lacquer for laser marking, wherein on the lower side of the carrier layer, an adhesive layer is present.

For the identification of parts on vehicles, machines, electrical and electronic devices increasingly technical labels are used, such as nameplates, as tax labels for process flows as well as warranty and Prüf piaketten.

In many cases, these applications inherently include the requirement for a more or less pronounced degree of counterfeit security. This counterfeiting security applies ostensibly for the period of attachment and the entire useful life on the part to be marked. Removal or manipulation should only be possible with destruction or visible, irreversible change.

In order to increase the counterfeiting security of the labels even more, the demand has been increasingly placed on the labels themselves to contribute to safety through a special design.

In particularly sensitive fields of application, a security level must also apply to the production of the labels. Too easy procurement and labeling of such labels as well as the production of plagiarism would allow unauthorized persons the unauthorized distribution of articles. However, this additional security against counterfeiting must not preclude subsequent identification of the glued label for originality by means of a fast, clear, simple and non-destructive method.

Labeling by means of laser labels is becoming more and more important in the automotive industry, especially for high quality markings. In this way, information and instructions such as tire pressure or fuel type for the future user on a variety of components of the car are placed. Even in the upstream production stages, important production data can be transported via a laser label.

For this application, the label can be labeled with a barcode. With a suitable reader, an assembly team has the opportunity to read information about the model, color and special features from the barcode directly on the production line.

In addition to this standard information, sensitive safety data such as chassis and identification numbers are also placed on the vehicle by means of labels. In the event of theft or accident, this information is of great importance for tracing the vehicle and manufacturing stages.

Due to the high cost of a laser marking machine compared to conventional label printing systems, direct imitation of the sign set is not possible for many criminal organizations. Counterfeits made by conventional printing techniques are easily recognizable visually. For this reason, many attempts are made to replace the signage of vehicles and to re-apply to other vehicles.

A peeled-off tag can easily give a stolen vehicle another identity (new chassis number). Retracing the vehicle is as good as impossible.

The label material used must therefore, as far as possible counterfeit-proof, to counter manipulation attempts. It may not detach from the bonding substrate without being destroyed.

In particular, it must not be possible to glue a detached label back to another surface without this manipulation becoming visible. Additional safety can be achieved through the high brittleness of the material in combination with high bond strengths. The adhesive force of the material on the primer plays a major role. It is decisive for the resistance to a manipulation attempt by detachment.

In addition to the standard material, there are modified labels that are to make it impossible to imitate the material by further security features such as embossing, holograms or a permanent UV footprint.

Powerful controllable lasers for baking markings such as fonts, encodings and the like are widespread. Amongst others, the following requirements apply to the material to be labeled:

• It should be easy to label.

• It should be achieved a high spatial resolution.

• It should be as simple as possible in the application.

• The decomposition products should not be corrosive.

In addition, special features are required for special cases:

• The characters produced by means of texturing should be so rich in contrast that they can be read error-free even over unfavorable conditions over long distances.

• High temperature resistance should be given, for example up to over 200 ° C.

• Good resistance to weathering, water and solvents is desired.

Known materials used for this, such as printed paper, anodised aluminum, painted sheet metal or PVC films, do not meet all of these requirements.

In DE G 81 30 861 a multilayer label of a thin and a thick self-supporting, opaque pigmented lacquer layer is disclosed. Both layers consist of an electron beam-hardened solvent-free applied paint, wherein the layer thicknesses are different. The labeling of the label takes place in that with the help of a laser, the upper thinner paint layer is burned away, so that the lower thicker lacquer layer becomes visible, the lower layer preferably having a contrasting color to the former.

This lettering is a type of engraving, which eliminates the manipulation possibilities as with traditional printing with inks and inks. The label is set by the raw materials used and the manufacturing process so brittle that removal of the same from the adhesive substrates is almost always possible only with destruction.

Such laser labels are used especially for a rational and variable labeling for the production of sign sets. These sets of signs contain the complete number of labels that are required, for example, in a motor vehicle on components subject to mandatory labeling (VIN plate, signs about tire pressure, boot load, characteristics of engines and units, etc.).

With regard to protection against counterfeiting, a laser film, as known from DE G 81 30 861 and obtainable, for example, as tesa 6930® from the company tesa, due to its very brittle product structure offers good prerequisites for documenting possible manipulation attempts and thus thwarting them.

The laser-printed label can only be removed at a very high cost and under certain conditions in a non-destructive way from its original bonding substrate.

This effort is so high that the said label all common Ablösbarkeitsprüfungen of the main testing institutions such as "Examination of factory plates from plates, sheets and films and their attachment by gluing" by the Federal Motor Transport Authority and "Marking and Labeling System Materials MH 18055" by Underwriters Laboratories Inc. easily exists.

This certified counterfeit security, which is always to be seen in relation to the effort required for the manipulation, must face increasing demands with regard to "tamper-evident" .This means that it should be documented with the aid of a glued laser label that the marked component is Since, as already mentioned, the laser film as well as laser marking systems are freely available on the market, there is a possibility for organized crime on a large scale.Stolen vehicles can with the help of the hardware and the freely available laser film with new Be equipped labels that are barely distinguishable from the actual original labels or not at all.

EP 0 645 747 A shows a laser-inscribable multilayer label material which comprises a first layer, a second layer differing optically from the first layer, wherein the first layer is laser-irradiated in accordance with a desired font or print image to visualize the surface the second layer is removable. Between the layers, a transparent plastic film forming a carrier layer is furthermore arranged.

DE 44 21 865 A1 shows a Einschichtlaseretikett of a carrier layer made of plastic, which contains an additive which shows a color change under laser irradiation. The carrier layer is coated on one side with a self-adhesive, which is optionally covered with a release paper or a release film.

DE 199 09 723 A1 has disclosed a security film which has a carrier layer in which an identification medium is contained. With the help of a non-contact labeling process, the diffusion properties of this identification medium can be specifically selectively and locally changed. If the security film labeled in this way is adhered to a workpiece, the identification medium diffuses toward the substrate surface, where it causes a detectable reaction. In this case, this diffusion or reaction takes place only in those areas of the substrate surface in which the diffusion capability was triggered or not hindered by the inscription process. Thus, the security film allows a clear labeling and identification of the workpiece.

The security film is labeled by means of a non-contact method. Thus, even in the factory environment a dirt-resistant, fast, flexible variable labeling can be achieved. The labeling of the security film - and thus the change of the diffusion properties of the identification medium - can be done in particular by means of electromagnetic radiation. Particularly advantageous for inscribing the security film is the use of a laser, with the help of both a temperature and a light-sensitive labeling can be done (the term "light" in this case, the entire laser-accessible area of the electromagnetic spectrum). Lasers have the additional advantage of enabling high-contrast labels with any choice of pattern, allowing rapid changes to the labeling pattern and being able to be used reliably in the factory environment.

For all of the above labels there is a high anti-counterfeiting security after application to an object, because the labels can be labeled only with technically sophisticated, thus expensive and therefore not accessible to all lasers, so that the equipment to copy the above labels or change can, at least in the past, for the most part, be more expensive than the product of interest. Furthermore, often causes the high brittleness of the material in manipulation and removal attempts destruction of the label.

With the technical progress, however, such lasers have become increasingly cheaper, so that the purchase of these, especially for larger products such as motor vehicles, the u.a. are provided in the engine room for labeling with such a label, in a growing number of cases worthwhile. Then the production of unauthorized plagiarism by the easy and freely accessible procurement of laser etiquette pre-material and inter-current widespread use of laser marking equipment is greatly simplified.

When using flat, sharp blades, it is also possible to separate labels completely from the substrate. Especially on plastic substrates such as polyethylene or polypropylene shows the bond between adhesive and substrate weaknesses.

Despite increased adhesion to metallic or painted substrates, it is also possible there to replace part of the labels without destruction by using special tools. A special blade tool can be placed under the label at a shallow angle. By careful cutting movements, it is possible to raise an edge, creating a so-called grip. In this way one creates an attack point, which simplifies a detachment. Furthermore, there is the constant requirement in addition to the prevention of counterfeiting and the prevention of plagiarism, the particular to be used in automotive label customization and to deliver exclusively to the customer.

This individualization must fulfill two important criteria, namely

• the label must be easily and quickly identifiable and

• the label must not be adjustable.

By means of these two criteria one can ensure that only the authorized entity, in this case the automobile operator, is able to define and mark components as originals.

Initial attempts to individualize the carrier material of the label are disclosed in DE 199 04 823 A1. Here, a method for producing a film is described in which initially a support carrier film is embossed by means of an embossing tool, wherein the embossing tool has holographic structures. Subsequently, a film is produced on the embossed support carrier film, so that at least one hologram appears on the film.

From DE 197 46 998 A1 laser label with at least one layer of plastic is known, which is coated on one side with a self-adhesive, wherein the plastic is incorporated for reversible magnetic or electrical marking suitable additive or a suitable for reversible optical marking additive, wherein the additive by means of electron beams, X-rays, in particular by visible light, especially by IR or UV rays recognizable, in particular made visible.

The object of the invention is to provide a label which meets the above requirement of improved security against counterfeiting, in particular to increase the security against forgery of laser-writable films to the extent that a glued label is hardly destructible even with the help of a cutting tool, but especially not again can be glued without this manipulation is detectable or detectable, and this continues to be particularly high contrast, high resolution, high temperature resistance and easy to use has.

This object is achieved by a label as described in the main claim. The subject of the dependent claims are particularly advantageous embodiments of the subject invention and the use thereof.

Accordingly, the invention relates to a label with increased security against forgery from at least one carrier layer, wherein an adhesive layer is present on the lower side of the carrier layer. In or on the exposed side of the adhesive layer, there are several discrete inclusions containing at least one reversibly detectable additive.

In a first preferred embodiment of the invention, the reversibly detectable additive in the discrete inclusions of the adhesive layer is an additive and / or optical detection suitable for magnetic and / or electrical detection, the additive being electron beams, X-rays, especially visible light, especially IR or UV rays visible, in particular made visible.

The discrete inclusions are preferably on the exposed side of the

Adhesive layer applied, in particular printed or coated.

The inclusions are preferably applied in regular patterns. It is possible,

To transfer lines, fields, pictures, logos, fonts etc. in different sizes and types.

Further preferably, the inclusions are arranged on the label pre-material, from which the labels are punched, arranged that in the individual stamped labels in the edge region punched inclusions are present, which are thus visible or accessible from the outside.

Particularly regular lines and line patterns create characteristic patterns of "luminous dots" on the edges of the labels and are particularly cost-effective and cost-saving Detection unit, usually a source of illumination, at the edge of the label to recognize a characteristic of colors and geometries pattern.

Further preferably, when the label is adhered to a substrate, the discrete inclusions are pressed into the adhesive in such a way that the layers of the label located above the inclusions deform so that haptically perceptible and optically visible impressions result in the surface of the upper carrier layer of the label.

The discrete inclusions are essentially formed by a polymer matrix, preferably varnishes, particularly preferably cationic UV varnishes. In a particularly advantageous embodiment, it is the cationically curable UV varnish SICPA 360076 from SICPA, Aarberg. Furthermore, suitable as printing varnishes SICPA 36-2 series cationic or UV flexographic coatings based on cycloaliphatic epoxy resins, the latter make up more than 30 wt .-% in the formulation of the coatings.

The height of the inclusions is in particular 1 to 20 microns, more preferably 0.5 to 20 microns. Preferably, the inclusions are printed on a liner which lays the adhesive, or directly on the adhesive layer.

As additives in the inclusions coloring particles are suitable, which may be fine color pigments or visible particles in the order of 0.1 to 5 mm. When using daylight fluorescent inks, the "fingerprint" can be recognized without assistance, which is why color pigments or particles are used which do not absorb in the area of visible light and are therefore invisible.The color pigments only become visible when the label is illuminated with a lamp of suitable wavelength stimulated and glow characteristic.

Furthermore, photoluminescent (phosphorescent) or fluorescent pigments can be used which are excited only or predominantly by UV radiation and emit in the visible region of the spectrum (for a review see, for example, Ullmann's Enzyklopadie der technischen Chemie, 4th Edition, 1979, Verlag Chemistry). However, IR-active luminescent pigments are also known. Examples of systems with UV fluorescence are xanthenes, coumarins, naphthalimides, etc., which are sometimes referred to in the literature under the generic term "organic phosphors" or "optical brighteners". The addition of a few percent of the relevant phosphors is sufficient, and in particular the integration into a solid polymer matrix is favorable in terms of luminosity and stability. For example, formulations with RADGLOO pigments from Radiant Color NV / Holland or Lumilux® CD pigments from Riedel-de-Haen can be used. Also inorganic phosphors are suitable. As photoluminescent substances, especially with the emission of light in the yellow range, metal sulfides and oxides, usually in combination with suitable activators, have proved favorable. These are available, for example, under the trade name Lumilux® N or as luminescent pigments improved in terms of stability, luminosity and persistence under the trade name LumiNova® from Nemoto / Japan.

In addition to stimulated by IR radiation color pigments or UV-active systems are also suitable in principle, phosphors, etc. by electron beams, X-rays. be stimulated.

These dyes / pigments listed by way of example are incorporated into the formulation of the preferred lacquer layer as polymer matrix in amounts of 0.1 to 50% by weight, preferably 1 to 25% by weight, very particularly preferably 7% by weight ,

When selecting the color pigments, care must be taken that they are sufficiently stable for the production process of the labels and do not change irreversibly in the process conditions (if appropriate, thermal drying, electron beam or UV curing). It is advantageous for long-term use of the labels that these most sensitive phosphors are embedded and protected in a polymer matrix of the inclusions.

In further advantageous embodiments, substances are used which can be detected magnetically or electrically, as well as thermochromic pigments which reversibly change color when the temperature changes. In an advantageous embodiment of the invention, the label consists of a) carrier layer made of plastic, b) contains an additive which shows a color change under laser irradiation, and the c) is coated on one side with an adhesive which d) optionally with a Release paper or a release film is covered.

The carrier layer preferably has a thickness of 10 to 200 .mu.m, in particular from 50 to 100 .mu.m.

Suitable carrier layers consist of plastics such as polyesters, poly (meth) acrylates, polycarbonate and polyolefins, as well as radiation-curable systems such as unsaturated polyesters, epoxy, polyester and urethane acrylates, which are also used for UV printing inks, in particular those of a base polymer according to US Pat DE G 81 30 816, namely aliphatic urethane acrylate oligomers.

Suitable additives are, in particular, color pigments and metal salts, in particular copper hydroxide phosphate or else iriodin, a pearlescent pigment, such as is commercially available from Merck. These additives are the base polymer (as described for example in DE G 81 30 861) in particular of the order of a few parts per thousand to a maximum of 10 wt .-%, preferably in amounts of 0.1 to 10 wt .-%, in particular of 0, 5 to 5 wt .-% based on the total weight of the carrier layer, admixed. After production of sheet material by known methods such as extrusion, casting, coating, etc., optionally with subsequent radiation-chemical crosslinking, such films are coated with the adhesive layer.

When using the standard laser, especially the widespread Nd-YAG solid-state laser with a wavelength of 1, 06 microns, takes place at the impact of the laser on the material surface, a color change or a color change instead, and it will get sharp, high-contrast labels and markings.

In a further advantageous embodiment, the carrier layer consists of a lacquer, in particular of a cured lacquer, preferably a radiation-cured lacquer, particularly preferably of an electron beam-cured lacquer Polyurethane acrylate varnish. In an alternative embodiment, the carrier layer is made of a polybutylene terephthalate.

Further preferably, on the upper side of the lacquer layer, ie the side opposite the side, is applied to the adhesive layer, an outer, in particular self-supporting, opaque pigmented lacquer layer preferably applied solvent-free, which is then in particular electron beam hardened.

The upper lacquer layer, formed by a cured, ie crosslinked, lacquer, preferably has a thickness of 1 to 20 .mu.m, in particular 5 to 15 .mu.m, the lacquer layer preferably having a thickness of 20 to 500 .mu.m, in particular 30 to 100 .mu.m.

In principle, four types of paint can be used, provided that their stability is sufficient, for example, acid-curing alkyd melamine resins, addition-curing polyurethanes, free-radical curing styrofoam and the like. However, radiation-curing paints are particularly advantageous, since they cure very quickly without lengthy evaporation of solvents or the action of heat. Such paints have been described for example by A. Vrancken (color and paint 83.3 (1977) 171).

Both paint layers have in a preferred embodiment against each other a maximum color contrast.

For the label according to the invention preferably consists of an opaque upper layer, which can be easily burned by a laser beam, a lower layer, in particular in a contrasting color to the first, wherein the lower layer is such that it is not easily burned by the laser beam.

In a further advantageous embodiment, a color with a fluorescent or phosphorescent additive is printed either on the lacquer layer or on the second lacquer layer, in such a way that the color layer between the two lacquer layers in the finished label.

In the case of two-layer and multi-layer labels, a suitable additive can be incorporated into the lacquer layer relevant for the writing. The outer lacquer layer itself, for example for the glossy type plates, thus remains unchanged, only at the Laser engraving exposes the lacquer layer partially at the points of the inscription. If color pigments, colored particles, colored fibers, etc. are present in the underlying, for example, white lacquer layer, these become visible at the engraved areas.

Also suitable as additives are the additives already mentioned in detail above.

These exemplary dyes / pigments are incorporated into the formulation of the respective lacquer layer in amounts of from 0.1 to 50% by weight, preferably from 1 to 25% by weight, very particularly preferably at 7% by weight.

After stamping / laser cutting the desired label geometries and the final inscription by laser beam with lettering, barcodes, logos, etc., the label is in its final form. When incorporating, for example, long-luminescent pigments into the lacquer layer, the label, after appropriate stimulation of the luminescent pigments, has a characteristic afterglow in the region of the laser inscription and at the edges, which permits easy and rapid identification as original label. Apart from the special light source and, if necessary, a screen against disturbing ambient light, no further complex equipment is necessary - after the test the label remains unchanged.

It is also possible to incorporate substances which can be detected magnetically or electrically in the lacquer layers mentioned, as well as thermochromic pigments which reversibly change color when the temperature changes.

In addition, offers as an additional hidden security level to add substances in the carrier layer, which lead to an electrical conductivity of the layer. With suitable measuring devices, which are portable, easy to use and inexpensive to procure, and suitable electrodes can be determined on the bonded label directly the conductivity of the paint layer. The electrodes are stopped at two different points A and B of the carrier layer, and a voltage is applied. In the presence of a continuous electrical conductivity between A and B, a current flow can be measured, which may have a characteristic value depending on the type and amount of the additive used. Because even with Use of the label directly on metals, the lacquer layer is separated from the conductive metal by the electrically insulating adhesive layer, no erroneous measurements are to be feared.

A counterfeiting by subsequent manipulation is particularly excluded by the fact that the conductivity measurement can be done not only from edge to edge of the labels, but between any points exposed by erosion.

So that a conductivity can be detected here, the complete carrier layer must be consistently three-dimensionally conductive. Such a laser-inscribable label can be produced by adding electrically conductive substances to the formulation of the preferred lacquer layer; This can be done in addition to the previous pigments or at least partially in replacement of the existing pigments in order to maintain the good processing properties of the paint pastes. In principle, electrically conductive metallic, organic, polymeric and inorganic substances are suitable as conductive additives, the use of metals being preferred. Especially for white or light lacquer layers, the own color of the conductive additive has to be considered for the selection. Conductive carbon black is also suitable, but only for black or dark paint layers.

In order to ensure a good conductivity, a minimum limit concentration of additive should be ensured, so that sufficient particles are present in the lacquer layer to make contact and to have contact with each other. If this limit concentration is undershot, a conductive path from A to B is no longer ensured in the three-dimensional structure of the base layer. Preference is therefore given to using metallic particles, preference being given to fibers having a high length to cross-sectional ratio, since in this case it is possible to ensure three-dimensional conductivity at lower concentrations than with spherical particles; In addition, the color change of the lacquer layer with the fibers is smaller. The metals used are preferably cost-benefit considerations copper, iron, aluminum and steel and their alloys, but also expensive, highly conductive metals such as silver, gold are suitable. The fiber dimensions are 0.1 to 50 mm in length and cross sections of 1 to 100 .mu.m, with preference being given to using metal fibers having a diameter of 2 to 20 .mu.m with a cross-sectional to length ratio of about 1: 100 to 1: 1000. Such fibers are in the 0.5 to 25 wt .-%, preferably 2 to 10 wt .-% in the known recipe homogeneously incorporated and coated according to DE G 81 30 861 and cured.

After adhesive coating and covering with release paper, label material is available which can be labeled with a laser beam. By removing the upper lacquer layer, the lettering of the lacquer layer is exposed in the area of the laser inscription - when a voltage is applied via suitable electrode contacts at two different points A and B of these inscriptions, a conductivity is measured which is characteristic for the lacquer layer and among other things by quantity and Type of conductive additive is determined. Thus, it is possible to produce customized label pre-material via defined recipes.

Further preferred is an embodiment of the label, which consists of at least one lacquer layer, obtainable in that on a printed or embossed support carrier film, the lacquer layer is preferably applied without solvent and then cured. The printing or embossing of the support carrier film produces a negative impression on the visible surface of the first lacquer layer of the label according to the invention.

The printing of the support carrier film takes place in particular by the flexographic printing process, because the UV flexographic printing process has a very high degree of freedom with regard to the design of geometries and can provide good print quality, especially for web-like materials from paper to film at the lowest possible price. With this technology, it is possible to transfer lines of fields, images, logos, fonts, etc. of different size and type from the cliche to the printing substrate.

In order to achieve a visible and sensible impression on the laser label later, the print should have a height of 0.1 μm to 15 μm. Preferably, a height of 1 to 5 microns to choose. Also, the pressure impression and -ausprägung can be varied by the course of the pressure points.

To realize the invention, the other conventional printing methods can be used, which are known as high-pressure process. These include book and screen printing. It is particularly preferred if the impression of the printed support carrier foil in the first lacquer layer is present as a depression of 0.1 to 15 μm, preferably of 1 to 5 μm.

The embossing of the support carrier film can be made, for example, with a embossing plate (available from Gerhardt) in different thicknesses or depths. The embossing depth depends on the set embossing pressure, which acts on the magnetic cylinder used in the embossing process and the type of counterpressure cylinder. A jacket of the impression cylinder (for example, with tesaprint ® or with a polyester film) causes a strong embossing.

Furthermore, the embossing tool used can have holographic structures, so that the structure is formed on the lacquer layer and results in at least one hologram.

The side of the stamping tool facing the stamping material is thus shaped such that a structure is produced which contains a diffraction grating or a holographic image.

Since the hologram is formed in the paint layer itself, a harmful multi-layer structure is not given, and the diffraction grating thus produced has the same durability and chargeability as the paint layer itself.

In an advantageous embodiment, the support carrier film consists of a duroplastic or thermoplastic material which is permanently embossed, in particular of polyester or polyamide.

In a further advantageous embodiment, an identification medium is contained in the carrier layer.

With the help of laser, the diffusion properties of this identification medium can be selectively selectively and locally changed. If the carrier film thus labeled adhered to a workpiece, the identification medium diffuses toward the substrate surface and there causes a detectable reaction. In this case, this diffusion or reaction takes place only in such inclusions of the substrate surface, in which the diffusion process was triggered or not hindered by the inscription process. Thus, the carrier layer allows a unique labeling and identification of the workpiece.

As identification medium, a substance is selected which triggers a detectable reaction on the substrate. For this purpose, the identification medium must be adapted to the material properties of the substrate. Thus, the identification medium may contain a dye, which is adapted to the substrate and which locally diffuses into the substrate surface and dyes it. Alternatively, the identification medium may include a substance that undergoes a chemical reaction with the substrate surface. Of particular interest in this case are reactions in which the substrate surface is locally removed or locally inflated, so that the lettering of the substrate can be detected optically or else tactually after removal of the film. In particular, an identification medium containing a corrosive substance is recommended for the marking of metallic substrates.

To increase theft protection, it may be advisable to choose an identification medium whose influence on the underlying substrate is not visible to the naked eye. This can be achieved with an identification medium which influences the absorption and reflection properties of the substrate, for example only in the UV or IR range, but not in the visible range.

The substrate contains no visible traces of the label. The affected areas still contain the marking, which can be detected by informed security forces simply with the help of, for example, a UV or IR viewing device. In particular, the identification medium can be chosen such that the detectability, for example the UV fluorescence, only occurs at certain wavelengths of the test light.

For industrial use of the carrier layer, in particular in the automotive industry, the film must have a high degree of robustness against temperature and light influences. These requirements can best be met if the security film has physical barriers which inhibit the diffusion of the identification medium in the blank state of the carrier layer.

During the labeling process these barriers are locally destroyed or weakened, so that in the so weakened areas a selective Diffusion of the identification medium can take place. In order to achieve a high temperature or light resistance of the label, the temperatures or light intensities required for the destruction of the barriers must be substantially higher than those to which the object to be marked in use - even under extreme environmental conditions - subject.

Such a diffusion inhibition of the identification medium, which can be canceled by a non-contact labeling can be advantageously realized by a micro-encapsulation of the identification medium in the carrier layer. The identification medium is enclosed in capsules whose walls are made, for example, of wax and / or fat and can be broken up, for example, by the local influence of heat in the affected areas of the film, so that the identification medium contained therein escapes and, when in contact with the Substrate - can diffuse into this or react with it.

A particularly high temperature resistance of the lettering can be achieved if the barrier is formed by a barrier layer which is arranged areally between the carrier layer and an adhesive layer and which prevents the identification medium from emerging from the carrier layer when the film is unlabeled. By labeling the carrier layer, the barrier layer is locally broken, so that the identification medium at these breakthrough sites escape locally from the carrier layer and diffuse into the adhesive layer. The areas of the barrier layer which remained intact in the inscription effectively prevent the diffusion of the identification medium and thus a reaction in these non-inscribed areas.

On the one hand, it is possible for the carrier layer to represent a type of matrix in which the identification medium is embedded. Alternatively, the substance of the carrier layer itself may represent the identification medium, so that the carrier layer consists of identification medium.

The carrier layers of the label are preferably labeled by means of a contactless labeling process. Thus, even in the factory environment a dirt-resistant, fast, flexible variable labeling can be achieved. The Labeling of the carrier layer can be carried out in particular by means of electromagnetic radiation.

Particularly advantageous for inscribing the carrier layer is the use of a laser, by means of which both a temperature-sensitive and a light-sensitive inscription can take place (the term "light" in this case encompasses the entire range of the electromagnetic spectrum which is accessible to the laser) the added benefit of enabling high-contrast captions with any choice of pattern, allowing rapid changes in the caption pattern, and being process reliable in the factory environment.

The adhesive layer can be composed of a pressure-sensitive adhesive and / or hot-melt adhesive and a heat-activatable reactive adhesive.

In one embodiment of the label, the pressure-sensitive adhesive and / or hot-melt adhesive are mixed with the heat-activatable reactive adhesive in the adhesive layer.

Further advantageous in the adhesive layer of the pressure-sensitive adhesive and / or hot melt adhesive and activatable by heat reactive adhesive are arranged alternately in strips.

In addition to the strip-shaped arrangement of the adhesive but also any other arbitrary partial geometric arrangements and shapes are possible, in particular punctiform, with varying distances of the adhesive, etc.

The selection of the arrangement depends on the particular purpose and location of the label.

The heat-activatable reactive adhesive preferably comprises i) a thermoplastic polymer in a proportion of 30 to 90% by weight, in particular 50% by weight, ii) one or more tackifying resins in an amount of 10 to 70% by weight, in particular 50 wt .-%, wherein the resins in particular to

Epoxy resins with hardeners, optionally also accelerators, and / or

Iii) optionally silver-plated glass spheres, iv) optionally metallised particles, v) optionally difficult or non-deformable spacer particles which do not melt at the reactivation temperature.

The preferred thermoplastic polyurethanes (TPU) are known as reaction products of polyester or polyether polyols and organic diisocyanants such as diphenylmethane diisocyanate. They are composed of predominantly linear macromolecules. Such products are usually commercially available in the form of elastic granules, for example from Bayer AG under the trade name "Desmocoll".

By combining TPU with selected compatible resins, the softening temperature can be sufficiently lowered. In parallel, there is even an increase in adhesion. As suitable resins, for example, certain rosin, hydrocarbon and coumarone resins have been found.

Alternatively, the softening temperature reduction can be achieved by the combination of TPU with selected bisphenol A and / or F based epoxy resins and a latent curing agent.

The chemical crosslinking reaction (based on epoxides or phenolic resin condensation) of the resins at elevated temperature achieves high strengths between the reactive adhesive and the surface to be bonded.

The addition of the reactive resin / hardener systems also leads to a lowering of the softening temperature of the above-mentioned polymers, which advantageously lowers their processing temperature and speed. The reactive adhesive is a self-adhesive product at room temperature or slightly elevated temperatures. When the product is heated, it also reduces the viscosity in the short term, allowing the product to wet even rough surfaces.

The compositions of the reactive adhesive can be widely varied by changing the nature and content of the raw material. Likewise, further product properties such as, for example, color, thermal or electrical conductivity can be achieved by targeted additions of dyes, mineral or organic fillers, for example silicon dioxide, and / or carbon or metal powders. The optionally contained in the reactive adhesive and / or the adhesive or hot melt balls and / or soft conductive particles allow conductivity in the z-direction, is also possible in the xy plane.

The pressure-sensitive adhesive and / or hot-melt adhesive is, for example, a pressure-sensitive adhesive, as disclosed in DE 15 69 898 C. The content of the entire disclosure of this document is thus part of this invention.

For example, an acrylate adhesive with 25 to 35 g / m ² composition is applied.

Due to the inventively designed adhesive layer, there is no impairment of the label. The physical and chemical resistance are not changed.

From the application point of view, the label does not suffer any loss of inscribability with a laser, readability of the information.

Further preferably, in the case of an inflexible carrier layer between the carrier layer and the adhesive layer, a reversibly flexible compensation layer is present, which softens or melts firmly at temperatures of up to 50 ° C. and at higher temperatures, and is able to compensate for occurring stresses.

Preferably, the compensation layer is made of thermoplastic materials such as polyvinyl acetate or polyamide.

Also suitable are all plastics consisting of linear or thermolabelled crosslinked polymer molecules, for example polyolefins, vinyl polymers, polyesters, polyacetals, polycarbonates or also polyurethanes and ionomers.

In addition, thermoplastics for the compensation layer can also be thermoplastically processable plastics with pronounced entropy-elastic properties, the so-called thermoplastic elastomers. The properties of the compensation layer can be varied widely by adding plasticizers, fillers, stabilizers and other additives as well as by fiber reinforcement.

The compensation layer can be coated from solution or drawn in as a film between the carrier layer and the adhesive.

The compensation layer preferably has a layer thickness of 0.2 to 20 μm. In a further preferred embodiment, the basis weight is 0.5 to 5 g / m ² .

The compensation layer is able to compensate for the stresses occurring in particular within the label, especially at high temperatures, by softening or melting them from a certain temperature range. Due to this plastic behavior, the stresses within the compensation layer are reduced. The label is thus flexible at high temperatures.

If the label or the substrate then cool again, the compensation layer changes to the solid state, so that the bond strength of the label is in no way impaired.

The melting and subsequent solidification of the compensation layer can be repeated almost as often as desired.

A further advantage of the invention is that the application possibilities can be defined via the properties of the compensation layer, for example the temperature at which the melting process begins.

The label according to the invention is distinguished by a multiplicity of advantages which were unforeseeable for the person skilled in the art.

• The labels are easy to recognize after application, they are visually visible and palpable.

• The identification is possible without aids, ie an authenticity check can be carried out without UV, IR lamps etc. • Since identification is clear, the risk of misjudgment is low.

• The label is hardly removable from the substrate.

• The label can not be re-glued without this manipulation being detectable.

After appropriate excitation of the (luminescent) pigments results in a characteristic

Afterglow in the area of the label margins, which is a light and fast

Identification as original label allowed.

After the second gluing, so the manipulation, results from the

Change of inclusions containing the additives another picture, so that the

Manipulation is immediately detectable.

Except the special light source and if necessary a privacy shield against disturbing

Ambient light is no further expensive equipment necessary.

Furthermore, in most cases, the haptic impression of the discrete

Inclusions in the label surface disappear, leaving a second

Security feature in the label is realized. The discrete inclusions are usually severed so that most of them are in the subsoil

Adhesive remains.

With reference to the figures described below, a particularly advantageous embodiment of the invention is explained in more detail, without wishing to restrict this unnecessarily.

Show it

1 shows the label with two carrier layers, on the lower side of the one carrier layer an adhesive layer is present, on which a plurality of discrete inclusions are printed,

Figure 2 shows the label of Figure 1 after the label on a

Substrate has been glued together with the impression of the inclusions in the surface, FIG. 3 shows the label according to FIG. 1 after the label has been peeled off the substrate by means of a sharp knife,

Figure 4 shows the label of Figure 1, after the label has been peeled off the ground by means of a sharp knife and at the same time the inclusions are affected.

In the figure 1, the structure of a label according to the invention is shown.

In the label there is a second lacquer layer 10 on the thicker lacquer layer 20, and this on a layer of an adhesive 40th

On the adhesive coating 40, a plurality of discrete inclusions 30 are printed, which consist of a polymer, in particular a paint, are present in the detectable additives.

When printing on the label, care has been taken to ensure that in the edge area of the label

Label punched inclusions 30 are present, which are thus visible or accessible from the outside.

FIG. 2 differs from FIG. 1 only insofar as the label has been bonded to a substrate 50.

The discrete inclusions 30 are pressed into the adhesive 40 in such a way that the layers of the label located above the inclusions 30 deform so that haptically perceptible and optically visible impressions 11 result in the surface of the upper carrier layer of the label.

FIG. 3 shows the label according to FIG. 1 after the label has been peeled off the substrate by means of a sharp knife. The knife thereby forcibly cuts through the adhesive coating 40, at the same time also the inclusions 30 are separated, so that parts of the inclusions 30 are in the adhesive 40a remaining on the label (30a), while the other parts 30b together with the other part of the adhesive 40b on Underground.

A detection of the additives in the inclusions 30a shows, when the label has been bonded again for another reason, that the amount of additives has become significantly lower, and in particular no longer with the originally present Quantity in the label of Figure 1 matches. Furthermore, the geometry of the discrete inclusions 30 has changed due to the "smearing", also an indication that a third party has manipulated the label.

After all

The expert can only conclude that has been manipulated on the label of Figure 3, that is, the label was peeled off and glued again.

Finally, the haptic impressions 11 of the discrete inclusions 30 in the label surface have disappeared.

In FIG. 4, the polymer matrix of the inclusions 30 is set in such a way that, as the inclusions 30 are severed, they are plastically deformed due to the shear stresses generated by the knife.

Although the inclusions 30 have been severed such that nearly the entire volume of each inclusion 30a has remained on the label, re-adhering the label without it being detectable is still impossible. The inclusions 30a have deformed due to the said stress in such a way that the image of the additives emerging by means of a detector no longer corresponds to the image as provided by the label according to FIG.

In the following example, a particularly advantageous label is to be disclosed, which is produced using a printed support carrier film, so that imprints arise on the label surface, which result in a further high safety factor.

example

The support carrier film to be printed, here a 50 μm polyester film, was printed on a UV flexo printing unit from SMB, subsequently UV-cured using a spotlight from G & W. The pressure level was between 1 and 5 microns. A cationic-curable UV varnish SICPA 360076 from SICPA, Aarberg, which is tinted blue, was used. By adding 5% by weight of cylinder repellent, the ink is optimized for processing.

The coating of the two polyurethane acrylate layers (laser layers) took place wet in wet, that is to say the upper functional layer (black) and the lower contrast layer (white) were coated on one another without prior curing of the black layer (advantage after curing high interlaminate adhesion). The black layer was coated directly onto the printed substrate and the white layer then onto the black layer.

The coating of the black layer was carried out via a Mehrwalzenauftragswerk (due to the lower and more precise layer thickness of 5 to 15 microns), and the white layer was coated over a doctor blade (100 to 160 microns). The paints were solvent-free "100%" systems based on aliphatic polyurethane acrylates, and the properties (viscosity) were adjusted by means of reactive diluents and copolymers hardened by electron beam curing at 80 KGy and 240 KeV laser stock.

The adhesive (pressure-sensitive adhesive according to DE 15 69 898 A1) was coated from a solution by means of a doctor blade (35 g / m ² ) and subsequently thermally crosslinked. The coating took place on the release film (liner). Only at the end of the laser pre-material was laminated together with the adhesive.

The printed backing sheet was removed, a negative impression of the geometry was recessed in the top coat.

Claims

claims

1. label with increased security against forgery of at least one carrier layer, wherein on the lower side of the carrier layer, an adhesive layer is present, characterized in that in or on the exposed side of the adhesive layer a plurality of discrete inclusions are present, which contain at least one reversibly detectable additive, wherein preferably with the bonding of the label on a substrate, the discrete inclusions are pressed into the adhesive in such a way that the layers of the label located above the inclusions deform, so that haptically perceptible and optically visible impressions result in the surface of the upper carrier layer of the label.

2. Label according to claim 1, characterized in that the carrier layer consists of a lacquer, in particular of a cured lacquer, preferably a radiation-cured lacquer, particularly preferably of an electron-beam-cured polyurethane acrylate lacquer.

3. Label according to claims 1 or 2, characterized in that on the lacquer layer, a second lacquer layer is applied, which is then cured.

4. Label according to at least one of claims 1 to 3, characterized in that the lacquer layer has a thickness of 20 to 500 .mu.m, in particular 30 to 100 microns and / or the second lacquer layer has a thickness of 1 to 20 .mu.m, in particular 5 to 15 microns.

5. Label according to claims 3 or 4, characterized in that both lacquer layers have mutually maximum color contrast.

6. Label according to at least one of the preceding claims, characterized in that the reversibly detectable in the discrete inclusions of the adhesive layer additive is a suitable for magnetic and / or electrical detection additive and / or optical detection, wherein the additive by means of electron beams, X-rays, in particular by visible light, especially by IR or UV rays recognizable, in particular made visible.

7. Label according to at least one of the preceding claims, characterized in that the discrete inclusions are applied to the exposed side of the adhesive layer, in particular printed or coated.

8. Label according to at least one of the preceding claims, characterized in that the discrete inclusions are formed substantially of varnish, preferably cationic UV varnishes.

9. Label according to at least one of the preceding claims, characterized in that between the carrier layer and adhesive layer, a flexible compensation layer is present.

10. Use of a label according to at least one of the preceding claims in the automotive industry