Patent Publication Number: US-10325527-B2

Title: Label for forgery-proof identification of an object, and method

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is the National Stage of PCT/EP2016/057908 filed on Apr. 11, 2016, which claims priority under 35 U.S.C. § 119 of German Application No. 102015105594.5 filed on Apr. 13, 2015, the disclosure of which is incorporated by reference. The international application under PCT article 21(2) was not published in English. 
     The application relates to a label for identification of an object, as well as to a method for production of at least one such label. 
     In the most varied fields of technology, objects are produced, processed and/or processed further, used or sold, the surface of which objects is provided with a label, permanently or at least temporarily, for example for identification of the individual object, for example with a serial number or part number, or to indicate other properties, components, purposes of use, manufacturer data or customer data, or any other kind of information, or also simply in order to affix symbols. 
     For example, in the most varied fields of technology, objects are produced, processed and/or processed further, which objects are coated or are to be coated with a paint layer. The object can be covered or painted with a paint layer from all sides, for example, or at least one side of the object is coated with the paint layer, for example on the entire or full surface, or in any case over part of the surface. The outside or the visible outer surfaces of the object, in particular, are frequently painted, above all in the case of objects that are exposed to weathering or the color design of which is intentionally selected. 
     In order to be able to identify such painted objects using labels, in reliable and lasting manner, i.e. in forgery-proof manner, irreversibly and permanently, labels configured in suitable manner are required. 
     Suitable labels are required, in particular, for vehicles, particularly for motor vehicles and for their components, accessories, vendor parts and replacement parts, etc., for example in order to thereby affix serial numbers, vehicle identification numbers (VIN; [in English:] Vehicle Identification Number), and other origin and manufacturer information, as well as inspection and approval identification, in forgery-proof manner. 
     Such information, such as, for example, the vehicle identification number VIN, is applied using self-adhesive labels, in more or less forgery-proof manner, for example using labels that contain a laser-inscribed colored laser film or a black and white laser film. Such labels can, however, be manipulated, forged, removed and/or replaced with a different label, with fraudulent intentions. For example, it is generally not easily evident from the paint layer of a vehicle part or the surface of such an object, after a label has been removed, whether and where a label was previously affixed to it. 
     In some cases, labels are used that have an adhesive layer applied to their rear side, which layer is permeated with Lumogens, i.e. with luminescent substances. After the label has been removed by an unauthorized person, it is possible to detect, at least using a UV lamp, whether and where the label was situated on the layer of paint, particularly vehicle paint, or on the surface. However, furthermore conclusions beyond this are hardly possible, other than that a manipulation effort obviously took place. However, manipulation can also be carried out to the effect that the luminescent outline of such a label is imitated, i.e. subsequently produced on the vehicle paint of the vehicle part. It is then difficult to determine whether a true imprint of an authorized VIN label or only a forged or imitated VIN label imprint is involved. Furthermore, in the case of luminescent imprints, even of true VIN labels, the luminescence effect decreases after a relatively short time; typically within a few months, so that finally, the outline of the label disappears completely. 
     In addition, there are labels in which detection means for visible detection of common solvents, which have already been used for fraudulent removal of labels from the vehicle parts, are contained. However, such labels only provide proof of manipulation if a solvent was actually used during the manipulation attempt. 
     Therefore, up to the present, there has been no satisfactory, reliable, and lasting solution for forgery-proof and manipulation-proof identification of the surface of objects, for example for labeling of paint layers of painted objects, i.e. of paint surfaces. A better and more forgery-proof possibility for affixing labels is required, among other things, for vehicles and vehicle parts, i.e. for their surfaces painted with vehicle paint or car paint. It would be desirable to make more reliable and more lasting identification possibilities available for this purpose. 
     It is the task of the present invention to make available a label that makes possible reliable, lasting, and stable identification of the surface of objects, for example of paint surfaces of painted objects and, in particular, of paint surfaces of vehicles and vehicle parts. Furthermore, a method for the production of such labels is supposed to be made available. 
     This task is accomplished by means of the label according to claim  1  and by means of the method according to claim  16 . 
     The label according to claim  1  possesses an inscribable, for example laser-inscribable layer composite, in which a visible inscription for identification of an object, for example a vehicle part or another painted or also unpainted object can be formed. 
     The label furthermore possesses an adhesive film and an active substance that penetrates into the surface of an object and/or acts on it when it is brought into contact with a surface of an object. 
     The active substance can be, for example, an active substance that penetrates into the vehicle paint and/or acts on the vehicle paint when it is brought into contact with vehicle paint or with a vehicle part painted with vehicle paint. 
     In the following, for the sake of brevity, reference will no longer be made to just any objects, but rather only to paint surfaces, i.e. to object surfaces formed from paint layers and/or provided with them, particularly to painted surfaces of vehicles and vehicle parts. Therefore, in the further description of this application, it will not constantly be explicitly pointed out that in place of labels or active substances contained in them, which are intended for vehicle paint or for some other paint, labels and/or active substances for other types of object surfaces, for example unpainted surfaces, are also being considered. The label or its active substance merely needs to have a composition such that the active substance interacts with the surface of the object or its coating, i.e. with the material or the material component at the surface of the object or the surface of its coating. The above circumstances are always presumed in the following description, and will not be explicitly repeated every time. 
     The active substance is disposed on the rear side of the label, optionally on the adhesive film or also underneath it, i.e. at an even greater distance from the front side of the label. Furthermore, the label is configured, on its rear side, in such a manner that when the label is adhesively affixed to a vehicle part or to a painted object, the active substance selectively comes into contact with the vehicle paint in partial surface regions of the rear side of the label. In this regard, the partial surface regions or the partial surface region, particularly their/its outlines are structured in the form of a further, invisible identification, which is not directly evident when looking at the label, particularly not from the front side of the label. 
     Contact of the active substance with the paint layer on the vehicle (or with the object surface) therefore only takes place selectively and furthermore in such a manner that the action of the active substance on the vehicle paint or its penetration into the vehicle paint begins immediately after the label is adhesively affixed to the vehicle. For this purpose, suitable active substances can be used, which dissolve or at least partially dissolve the vehicle paint, i.e. initiate dissolution, or which, in any case, bring about a change on or in the paint layer and/or its surface, which change is detectable, visible or at least recognizable. The active substance does not necessarily need to bring about a change that immediately strikes the eye, such as discoloration, for example; it is sufficient if the action of the active substance on the vehicle paint or on the other material that forms the surface of the object or its coating has a composition such that a change can be recognized, at least by the trained eye of the dealer, for example vehicle dealer, or another expert. The label furthermore preferably has such a composition that the change in the vehicle paint, for example, starts to form immediately after the label is adhesively affixed to the vehicle part, i.e. not only when the label is removed. 
     Furthermore, the label preferably has a composition such that the identification in the vehicle paint or in the other material at the surface of the object or of the material of its coating continues to exist in lasting manner, and does not disappear again even after the label is removed. Furthermore, the label has a composition such that even after the label—or, in any case, its adhesive film and the layer composite disposed above it, to be inscribed or having been inscribed in visible manner—is removed, the action of the active substance on the vehicle paint continues, and preferably even more active substance can penetrate into and/or act on the vehicle paint or the other material of the object or its coating. 
     The label according to the embodiments of this application has a structured active substance layer that is configured not over the full area, but rather only over a partial area, i.e. is present only in one or in multiple partial surface regions of the basic label surface, and is therefore left out in the remaining part of the basic label surface. The remaining (basic) surface region of the label is therefore free of active substance, specifically over the entire layer thickness of the label or its layer composite. Therefore the contour of the inscription, identification or other item of information that can be transferred to the object and is preferably invisible, at first, is not predetermined by the contour of the label or its basic surface, but rather by the partial surface region(s) (i.e. its/their contour, location and/or size) in which active substance is present in the label. The distribution of active substance over the basic surface of the label, in terms of area, is therefore independent of or different from the contour of the label. Furthermore, it is independent of the contour of the first, visible inscription on or in the label. The further inscription preferably differs from the first, visible inscription, and is transferred or can be transferred when the label is adhesively applied, from the rear side of the label onto the object (either immediately or over a certain period of time). 
     Here, the basic label surface is understood to mean the surface area over which the label extends, and which results from the contour or the lateral dimensions of the label. If the label or its layer composite has punched-out regions or other recesses over its layer thickness, these recesses do not belong to the basic surface of the label, even if they are surrounded or encircled by the label or its basic surface. Furthermore, the rear side of the label, i.e. rear side of the label surface, with which the label can be dispensed onto the object in order to identify it, must be distinguished from the basic label surface. 
    
    
     
       Some exemplary embodiments will be described below, making reference to the figures. These show: 
         FIG. 1  a schematic top view of a label on an object, for example a vehicle part, 
         FIG. 2  a schematic cross-sectional view through a label, according to one embodiment, 
         FIG. 3  a detailed cross-sectional view which shows a futher structured layer of the label, 
         FIG. 4  a schematic cross-sectional view of an object provided with the label from  FIG. 2  or  FIG. 3 , particularly a vehicle part, 
         FIGS. 5A to 5C  the vehicle part from  FIG. 4  after removal of the label according to different embodiments, 
         FIG. 6  a schematic top view of the surface of the vehicle part from  FIG. 5A, 5B or 5C , 
         FIG. 7  an alternative example of a label, 
         FIG. 8  a first method for the production of a label composite, and 
         FIG. 9  a second method for the production of a label composite. 
     
    
    
       FIG. 1  shows a schematic top view of a partial piece of an object  35 , the surface of which is provided with a label  10 . The object can be a vehicle part  25 , for example; in particular, a vehicle part  25  painted with vehicle paint. The object can furthermore be an otherwise painted object  35 , i.e. covered or provided with a paint layer. The object can furthermore be another type of object, on the surface of which a label is to be affixed. The object can also be unpainted, for example. 
     Irregardless, in the following, when explaining the figures, for the sake of brevity only a vehicle part will be discussed. 
     The vehicle part  25  is preferably painted with a paint  20 , for example vehicle paint; accordingly, the surface of the vehicle part  25  is a painted surface, and the upper layer of the vehicle part  25  is a paint layer composed of vehicle paint  20 . Underneath that, a metal or a metal alloy, for example, is situated, of which the vehicle part or the object  35  or a significant part of it consists. 
     The adhesively attached label  10  carries a visible and directly readable inscription  5  on its front side  10   b , shown in  FIG. 1 , which inscription serves for identification of the vehicle part or of the entire vehicle or object, or it is at least intended for being inscribed with such an inscription. The inscription  5  or visible/readable identification is a vehicle identification number (VIN; Vehicle Identification Number) or another type of inspection or approval identification, alternatively test identification, manufacturer information, a replacement part number, a logo, a graphic element, or some other type of information, or a combination thereof. 
     The label  10  is preferably a laser-inscribed or laser-inscribable label. The layer composite  1  is preferably a laser-inscribable layer composite, and comprises a colored laser film  2 , for example. The adhesive layer, i.e. the adhesive film  3  of the label  10  is disposed on the rear side of the layer composite  1 . 
     In the case of a conventional label, the adhesive film  3  lies on the paint surface of the vehicle part  25  over the full area. In the case of the label  10  shown here, however, a further inscription or other type of identification, which is invisible or in any case cannot be recognized from the front without technical aids, and covered by the label itself, is worked into the label, on the rear side of the label and when the label is adhesively affixed to the vehicle part  25 , is transferred to the part or to its paint layer  21 , i.e. to the surface of the object  35  or its coating, and remains on the paint layer  20  of the vehicle part  25  or the surface even after the label has been removed, as an irreversible change. 
       FIG. 2  shows a schematic cross-sectional view of the label from  FIG. 1  according to a first exemplary embodiment. The layer sequence for implementation of the layer composite  1 , which incorporates the colored laser film  2  or—according to alternative embodiments—the other inscribable film—is only indicated schematically and will not be discussed in greater detail here. In the case of the label  10  from  FIG. 2 , a structured active substance layer  24  is disposed on the underside or rear side  10   a , which layer covers partial regions of the adhesive layer  3  from below. In  FIG. 2  and the subsequent figures, the dimensions, particularly the layer thicknesses, are not represented true to scale, and are shown in exaggeratedly large size, in part, for a clearer illustration. The structured active substance layer  24  disposed on the rear side  10   a  of the label  10  contains an active substance  4 , which is selected in such a manner that when it is brought into contact with vehicle paint, i.e. with a vehicle part painted with this paint, acts on the vehicle paint and/or penetrates into the vehicle paint. The active substance can particularly be a paint solvent or another medium that changes paint, furthermore substances that can be detected and are capable of diffusion in the vehicle paint, particularly substances with luminescence properties. The active substance  4  or the active substance layer  24  is disposed only in partial regions of the rear side  10   a  of the label, and forms a further, at first invisible identification, starting from the point in time that the label is dispensed, which identification is generally different from the visible inscription  5  on the front side  10   b  of the label  10 , and only appears or becomes recognizable for a trained eye when the label, which was adhesively affixed to the vehicle part  25  over a certain minimum period of time, which can be relatively short (for example a few months, weeks, days or even shorter; possibly a few seconds are sufficient), is removed from the vehicle part  25 . 
     The active substance  4  does not necessarily have to be an active substance that is intended for vehicle paint or for another paint, i.e. one that interacts or reacts with it, but rather merely needs to be selected and/or composed in such a manner that the active substance  4  interacts with and/or penetrates into the surface of the object  35  to be labeled or its coating, i.e. with the material or a material component at the surface of the object  35  or the surface of its coating. 
     Regardless, in the following explanations reference will be made only to active substances that interact with paint or vehicle paint or change it, for the sake of brevity. 
       FIG. 3  shows a more detailed cross-sectional view which additionally shows a further structured layer of the label, namely an ultra violet (UV) protection layer  26  and/or an adhesion-reducing layer  27  or a layer which combines these two properties in itself. For example, this is a layer that consists of UV protection paint  6  or at least contains it. For the sake of clarity, the representation is slightly magnified as compared with  FIG. 2 ; according to  FIG. 3 , the active substance layer  24  and the UV protection layer  26  or adhesion-reducing layer  27  are structured to have the same coverage, i.e. layer stacks of a double layer occur, with a lateral contour or structure that corresponds to the desired inscription to be left on the paint surface of the vehicle (for example a repeated sequence of letters XYZ; see  FIG. 6 ); for example to a manufacturer name of a vehicle manufacturer. 
       FIG. 4  shows a vehicle part  25  provided with the label  10  from  FIG. 2  or  FIG. 3 . Partial surface regions of the paint layer  20  come into contact with the active substance layer  24  on the rear side of the label, starting from the point in time when the label  10  is adhesively affixed, and are exposed to the action and/or penetration of the active substance  4  starting from this point in time. The active substance  4  is a paint solvent  4   a , for example, which locally dissolves the paint surface, initiates dissolution at the surface, liquefies it, dilutes it, or reacts with the material of the paint layer  20  or changes it. Pancreatin or N-methyl-2-pyrrolidone (NMP), for example, can be used as the active substance  4  or paint solvent  4   a . Alternatively, the active substance  4  can be a luminescence substance  4   b , particularly a fluorescence substance, which is able to diffuse or migrate within the vehicle paint layer  20 , as indicated in  FIG. 4 , in the paint layer composed of vehicle paint  20 , by means of active substance particles or active substance molecules represented in dot form. The surface pieces of the active substance layer  24  thereby serve for formation of lettering that is exposed or is to be exposed after removal of the label, for example manufacturer information or another identification or information listed above. 
       FIG. 5A  shows the vehicle part  25  from  FIG. 4  after removal of the label  10  according to a first embodiment of the label, in which the surface pieces of the active substance layer  24  come loose from the adhesive film  3  when the label  10  is pulled off, and remain adhering to the paint surface of the vehicle part  25 . Alternatively, the label  10  can also be configured in such a manner that the active substance layer regions  24  are pulled off from the vehicle paint  20  again, simultaneously with the label. In both cases, however, part of the active substance  4 , for example of the luminescence substance or the paint solvent, remains in the paint layer of the vehicle part, particularly close to the surface of the paint layer and in surface regions directly under and adjacent to the surface regions of the active substance layer  20 . As a result, a further inscription or identification, which can be detected either using aids such as UV lamps or—preferably particularly in the case of use of paint solvents such as pancreatin or NPM (N-methyl-2-pyrrolidone), for example—is recognizable for a trained eye, even without aids, occurs in the paint layer. The two paint solvents mentioned above furthermore have the advantage that their traces in the vehicle paint are almost impossible to remove. 
       FIG. 5B  shows a surface deformation in the vehicle paint, as it occurs locally due to the action of pancreatin or NMP on the paint surface there. In those surface regions that were previously covered by the active substance layer  24 , the paint surface of the vehicle paint  20  has become uneven as the result of the paint-dissolving effect. Typically, slight elevations occur at the edge of the surface regions covered with pancreatin or NMP, which elevations surround the surface piece treated with the active substance  4 ;  4   a , in each instance. In the surface regions previously covered with active substance, either the paint composition is changed, the layer thickness of the paint layer is slightly reduced, or the material of the paint layer  20  is changed in some other way, as indicated in  FIG. 5B . According to  FIG. 5B , when the label is pulled off, it is removed in its entirety; including the surface pieces of the structured active substance layer  24 . The exemplary embodiment according to  FIG. 4 , in combination with  FIG. 5A  (instead of  FIG. 5B ), in contrast, allows even subsequent action or penetration of further active substance  4  into the vehicle part  25  over a period of time, even after the label  10  was removed a long time ago. 
     According to the further development shown in  FIG. 3 , the structured double layer composed of active substance layer  24  and UV protection layer  26  (or, alternatively, of an adhesion-reducing layer  27 ) can also be transferred to the paint surface. Then the depressions shown in  FIG. 5B , surrounded by outer edge elevations, continue to be covered with the surface pieces of the structure active substance layer  24 , preferably also with the surface pieces of the UV protection layer  26  and/or the adhesion-reducing layer  27 , which are disposed above them, with the same coverage, even after removal of the label, as shown in  FIG. 5C . This has the advantage that even after removal of the label  10  from the paint layer of the vehicle part  25 , the remaining surface pieces of the active substance layer  24  continue to bring about the formation or stabilization of the inscription or other identification on the paint surface; furthermore, the active substance is protected against environmental influences by the protective layer  26 ;  27 , and thereby better preserved, over an even longer period of time. In the case of a UV protection layer  26 , instead of a paint solvent  4   a , luminescence substances  4   b , for example, can be protected against decomposition caused by UV radiation, particularly by direct or indirect sunlight. Even when using other protective layers, the respective active substance  4  can continue to develop its unreduced effect even after removal of the rest of the label, i.e. of the adhesive film  3  and of the layer composite  1 , on and/or in the paint layer of the vehicle part  25 . 
       FIG. 6  shows a schematic top view of an inscription or other identification, as an example, as it can be produced on and/or in the paint layer of the vehicle part, using the active substance  4 ;  4   a ;  4   b . The surface section shown in  FIG. 6  is, for example, a surface cutout of the basic label surface. In partial regions of the basic label surface, i.e. in partial surface regions  8 , which correspond to lettering or some other identification or part of it, the paint layer has been changed, for example deepened by means of a dissolution process that has at least taken place in the meantime, made less shiny or matte, discolored, made lighter or darker than in the untreated surface regions, or changed locally in some other way. In the example in  FIG. 6 , the partial surface regions  8 , which correspond to the surface pieces of the active substance layer  24  or its recesses, each form individual letters of a lettering (here: XYZ) that stands for a manufacturer name, as an example. The identification produced in this manner is configured, for example, in the form of a scatter print with a plurality of identical inscription fields  9 , or at least fields having the same content, here, for example, in the form of an arrangement of many repetitions of the lettering XYZ. The partial surface regions  8  of an individual inscription field  9  are, for example, letters or alphanumeric symbols, the outlines of which correspond to the edges of the surface pieces of the active substance layer (if applicable in addition to the UV protection layer  26  or other protective layer) or its recesses, which pieces were previously in contact are still in contact after removal of the label. The outlines correspond, for example, to the edge elevations shown in  FIG. 5B and 5C , as they are formed, for example, by means of the action of the paint solvents pancreatin or NMP (N-methyl-2-pyrrolidone). Alternatively, the partial surface regions  8  can be surface regions in which a luminescence substance has diffused into the paint layer and fluoresces when acted on by a UV lamp. The images of the contour or the surface content of the structured active substance layer  24 , shown in  FIGS. 2 to 6 , which are produced in the paint layer of the vehicle part, can also be the negative image of the inscription or of the motif, instead of an inscription or some other motif. 
       FIG. 7  shows an alternative example of a label. While in  FIG. 2 , the active substance  4  is disposed in the active substance layer  24  and thereby on the adhesive film  3 , stated more precisely underneath the adhesive film  3 , and in  FIG. 3 , the active substance  4  is contained even deeper, namely in the active substance layer  24 , at a distance from the adhesive film  3 , by means of the protective layer  26 ;  27 , the active substance  4  according to  FIG. 7  is situated in the adhesive film  3  itself. The adhesive film  3  is completely permeated with the active substance  4 ;  4   a ;  4   b , but the film itself is not configured over the full area, but rather only over a partial area on the rear side of the label. Therefore the adhesive layer  3 ;  24  that contains active substance itself forms that partial surface region  8  or those partial surface regions of the rear side of the label, where the active substance can penetrate into the surface of an object when it makes contact with the latter, for example .a paint layer of a vehicle part or some other paint-coated object. The remaining partial surface region of the basic label surface or rear side of the label, in which the adhesive layer  3 ;  24  that contains active substance is absent, in contrast leaves the surface of the object unchanged, i.e. does not act on the surface of the object. For this reason, no active substance of any kind can penetrate into or act on the surface of the object there, i.e. in the remaining partial surface region without an adhesive layer that contains active substance; not even, for example, under disadvantageous circumstances, such as elevated temperature, severe weathering or many years of use of the labeled object, which is invisibly identified under the label. 
     In those embodiments of this application in which the active substance or the active substance layer is disposed on the rear side of the label “underneath” the adhesive film, the formulation “underneath” means that—viewed from the top side of the label—the active substance or the active substance layer is disposed even deeper than the adhesive film. This means, in other words, that the active substance or the active substance layer—viewed from the top view of the rear side of the label—is disposed “on” the rear side of the label and/or “on” the adhesive film, either directly on it or (viewed from the rear side of the label) “above” the rear side of the label and/or of the adhesive film; for example, spaced apart from the adhesive film by the layer thickness of the UV protection layer. 
     The adhesive layer  3 ;  24  that contains active substance is therefore structured—analogous to the separate, additional active substance layer  24  of  FIGS. 2 and 3 —within the basic label surface, i.e. configured merely over a partial area instead of the full area. In this regard, the recesses in the adhesive layer  3 ;  24  that contains active substance from  FIG. 7  correspond to the non-covered regions of the rear side of the label between the surface pieces, i.e. partial regions  8  of the active substance layer  24  from  FIG. 2 or 3 . As a result, the same positive image occurs as that using the labels  10  of  FIGS. 2 and 3 , for example the positive image shown in  FIG. 6 . Likewise, however, a negative image can also be produced; for this purpose, the surface pieces of the layer  24  that contains active substance and its recesses must be interchanged with one another, in each instance, in  FIG. 7 . The same holds true analogously for the active substance layer  24  in  FIGS. 2 and 3 . 
     Typical layer thicknesses for the layers of the label shown in  FIGS. 2, 3, and 7  amount to 15 to 50 μm for the adhesive film  3 ; 2 to 20 μm for the (additional) active substance layer  24 ; and 5 to 50 μm for the protective layer  26  (if present), for example. Instead of a UV protection layer, the layer  26  can also be an anti-adhesion layer or adhesion-reducing layer  27 , which facilitates loosening of the surface pieces of the active substance layer  24  from the adhesive film  3  when the label is pulled off. The layer  26  can also combine these two functions in itself and then contain a UV protection paint  6 , as well as silicone or some other adhesion-reducing medium, for example. If an adhesive film that contains active substance is present, it can possess a layer thickness between 2 and 50 μm, for example. 
     For the remainder, the layer thicknesses can be suitably selected in accordance with the method and implementation of the respective printing process. The parting layer or the active substance layer, if application in combination with the intermediate layer (UV protection layer  26  and/or adhesion-reducing layer  27  composed of silicone, for example) can optionally be imprinted on the rear side  10   b  of the label or on the rear side  3   a  of the adhesive film  3 , particularly by means of flexographic printing. Alternatively, these layers or at least one of them can be imprinted onto a carrier film disposed under the rear side of the label, for example using screen printing, on the silicone-coated side of the carrier film. In the latter case, the layers  24 ;  26  come into contact with the rears side  3   a  of the adhesive film  3  when labels and carrier film are joined together. If a combined UV protection and anti-adhesion layer  26 ;  27  is present, this can contain a proportion of 20% to 40%, for example 30% silicone, and consist of UV protection paint for the remainder. 
       FIG. 8  schematically shows a first exemplary embodiment of a method for the production of a label composite, which composite comprises a label or a plurality of labels according to the present application. In the method, conventional materials, particularly a label film web  21  and a carrier film web  22 , are used; preferably as finished, prefabricated rolled goods, in which the carrier film web is already releasably adhesively affixed, with its front side, to the rear side of the label film web, i.e. onto its adhesive film. The label film web  21  is a conventional, prefabricated product for inscribable labels, for example, particularly for laser-inscribable labels. Accordingly, the label film web  21  preferably comprises a colored laser film  2  or a layer composite  1  comprising such a colored laser film, as it was already mentioned in connection with the above figures. The label film web  21  possesses an adhesive film  3  on its rear side. The carrier film web possesses a silicone coating on its front side, or some other coating that reduced adhesion or adhesive strength, thereby causing the carrier film to be adhesively affixed to the adhesive film in releasable manner. 
     In the method according to  FIG. 8 , an active substance layer  24 , which contains the active substance  4  for forming an additional, concealed identification on the vehicle parts to be labeled, is imprinted on the label film web  21  as a rear-side active substance layer  24 . For this purpose, the label film web  21  and the carrier film web  22  are temporarily separated from one another, over a partial piece of their length, in order to be able to imprint selectively chosen surface regions of the adhesive film  3 . Preferably, the printing process is carried out by means of flexographic printing, with other printing techniques also being fundamentally possible. According to  FIG. 8 , the active substance layer  24  is selectively imprinted onto surface regions of the rear side  10   a  of the label film web  21  using a printing roll  18 . 
     Therefore surface regions or surface pieces of the active substance layer  24 , which contain the active substance  4 , are formed on the rear side of the label. 
       FIG. 8  furthermore shows a further development, in which a UV protection layer  26 , which contains a UV protection paint, is also additionally imprinted onto the adhesive film  3 , specifically with the same coverage with the surface pieces of the active substance layer  24 . In this regard, first the surface pieces of the layer  26  are imprinted onto the respective surface regions of the adhesive film  3 , and afterward, the surface pieces of the active substance layer  24  are imprinted onto the rear side of the surface pieces of the layer  26 . Here, too, flexographic printing is preferably used. Subsequently, the rear side of the label film web  21  is dried using a dryer  19 , and finally, it is brought together again with the carrier film web  22 . In this process, the finished label composite  40  is formed, either as a rolled product (as shown) or as a sheet product, which can be fabricated; in this composite, the surface pieces of the active substance layer  24  and, if applicable, also surface pieces of the UV protection layer  26 , are disposed between the carrier film web  22  and the label film web  21 , i.e. between the carrier film  30  and the label  10 . The labels that are punched from the finished label composite  40  are therefore suitable for forming concealed identifiers in the paint layer of vehicles, in the paint layer on other objects or, in general, on the surface of any desired objects  35  or the surface of their coating. 
     In deviation from  FIG. 8 , an adhesion-reducing layer, for example a layer containing silicone, can be imprinted in place of the UV protective layer  26 , before the active substance layer  24  is imprinted on it. The active substance  4  is then not a luminescence substance  4   b , for example, but rather a paint solvent  4   a , such as pancreatin or NMP, for example. Furthermore, a layer that contains both a UV protection paint and silicone or another substance for reducing the adhesion to the adhesive film  3  can be printed as the layer  26 . Nevertheless, here the adhesion is stronger than the adhesion between the active substance layer  24  and the carrier film web  21 ; when the carrier film web is released during dispensing of the label, the active substance layer  24  therefore remains adhering to the label  10 . 
     According to a further modification of  FIG. 8 , an adhesive layer  3  that contains active substance is alternatively used in place of the separate, structured active substance layer  24  (and, if applicable, the layer  26 ), but this layer is imprinted only over part of the surface of the rear side  10   a  of the otherwise adhesive-free label film web  21 . In this modification, an adhesive film  3 ;  24  that contains active substance is used, i.e. one that itself already contains the active substance  4 . Therefore no diffusion of active substance into the paint layer of a labeled vehicle part, for example, is possible on the remaining surface regions of the (rear-side) basic label surface that is not coated with adhesive. The adhesive layer  3 ;  24  that contains active substance is structured laterally, i.e. within the respective basic label surface, and thereby predetermines the shape or contour of the further inscription, which is at first invisible. 
       FIG. 9  shows an alternative second method, in which the active substance layer  24  is imprinted onto the carrier film  30  or onto the carrier film web  22 . Preferably, screen printing is used as the printing technique. According to  FIG. 9 , the surface pieces or surface regions of the active substance layer  24  are imprinted onto the front side of the carrier film web  22  (for example by means of a corresponding printing screen  23 ), after the carrier film web  22  was separated from the label film web  21 . As compared with the figurative representation in  FIG. 9 , the same modifications are possible, which have already been described with reference to  FIG. 8 . Therefore pancreatin, NMP or some other paint solvent  4   a  can be contained in the active substance layer  24  as an active substance  4 , in place of a luminescence substance. Furthermore, instead of a separate active substance layer  24  under the adhesive layer, alternatively an adhesive layer  3 ;  24  that contains active substance but is structured can be imprinted onto the carrier film web  22 , particularly an adhesive film that already contains the active substance  4 ;  4   a ;  4   b.    
     If, according to  FIG. 9 , an active substance layer  24  is printed, and the active substance is a luminescence substance  4   b , a further development provides that surface pieces of a UV protection layer  26 , having the same coverage, are subsequently imprinted onto the surface pieces of the active substance layer  24 ; preferably, once again, by means of screen printing. The surface pieces or layer stacks that are produced are subsequently dried, and afterward, the label film web  21  and the carrier film web  22  imprinted on the front side are joined together again. As a result of the adhesive layer of the label film web  21  with the labels  10 , the printed layers or layer stacks  24 ;  26  now adhere to the rear side of the adhesive layer  3  more strongly, i.e. they are released from the carrier film together with the remaining parts of the label when the label is later pulled off the carrier film. The finished label composite  40 , just like that from  FIG. 8 , contains ready-to-use prefabricated labels according to the present application, where it is possible to prefabricate sheet products instead of rolled products, as well. 
     The label according to the embodiments explained in this application has a composition such that the further, preferably at first invisible inscription, identification or other item of information that is transferred to an object, onto its surface, by means of dispensing the label, results not from the contour of the label as a whole, but rather from the distribution of the active substance over the area, on or close to the rear side of the label. Furthermore, the label has a structure such that those surface regions in which no active substance is supposed to be able to penetrate into the object or act on it are free of active substance, specifically over the entire layer thickness of the label. This guarantees reliable transfer and thereby formation of a clearly outlined image of the original active substance distribution over the surface of the label (which image is clearly recognizable after removal of the label from the object), on or in the object or its surface, specifically even if the duration of action during which the label was dispensed onto the object was very short (for example only a few weeks), if the time period since removal of the label was very long (up to months or years) and/or if varying temperature influences, weathering influences or other influences have already made the readability or recognizability of the contours of the transferred (further) inscription on the object more difficult to ascertain. 
     The inscription, which is transferred to the object as intended, is an inscription that is latently present in the label, and is predetermined by means of the selective distribution of the active substance over the basic surface of the label or by the label surface. This inscription, identification or other item of information, along with the readable inscription that is visible on the front side, forms an additional, further inscription that is preferably not visible on the label; not even from the exposed rear side of the label. This inscription, identification or other item of information is transferred or at least can be transferred, as intended, when the label is adhesively affixed to an object, onto this object or its surface. Transfer of the further inscription does not already need to take place when the label is dispensed, but rather can happen during a longer period of time, if necessary, after the label has been dispensed, particularly since the label is often not intended just for staying on the object for a short time, but rather mostly for identifying the object over an extended period of time of several months or years, for example. The characteristic according to which the further inscription, identification or item of information formed by the structured active substance surface is transferred from the rear side of the label to the object when the label is adhesively affixed merely means that the further inscription, identification or item of information of the label becomes “transferable” to the object, i.e. the process of transfer to the object (by means of its action or penetration into its surface) can begin and/or does begin starting from the point in time when the label is adhesively affixed or dispensed. The period of time that is then required so that the further inscription is transferred to the object with sufficient clarity can be very short or, depending on the embodiment and the type of active substance, can also be a longer period of time, for example a period of several hours, days, weeks or possibly months. 
     REFERENCE SYMBOL LIST 
     
         
           1  layer composite 
           2  colored laser film 
           3  adhesive film 
           3   a  rear side 
           4  active substance 
           4   a  paint solvent 
           4   b  luminescence substance 
           5  inscription 
           6  UV protection paint 
           7  adhesion-reducing substance 
           8  partial surface region 
           9  inscription field 
           10  label 
           10   a  rear side 
           10   b  front side 
           18  printing roll 
           19  dryer 
           20  vehicle paint 
           21  label film web 
           22  carrier film web 
           23  printing screen 
           24  active substance layer 
           25  vehicle part 
           26  UV protection layer 
           27  adhesion-reducing layer 
           30  carrier film 
           35  object 
           40  label composite 
         VIN vehicle identification number