EP3060408B1 - Method for forming at least one three-dimensional structure on at least one surface of a substrate and transfer film - Google Patents

Description

The present invention relates to a method for forming at least one three-dimensional structure on at least one surface of a substrate, in particular a value or security product or a precursor of a valuable or security product. Such value or security documents may be, for example, a personal document, a check card, a non-personalized authorization card, such as a ticket or a means of payment, or a value or security element intended for product assurance.

Value or security products, in particular securities or security documents, serve to verify the identity of a person or thing or a claim, for example, for payment of a sum of money or for the issue of a product or service. For this purpose, it must be ensured that the product can not be imitated, counterfeited or falsified with considerable effort. The product therefore contains security features whose imitation is extremely difficult or even practically impossible. For example, the product, such as banknotes, consists of a not readily available material. Additionally or alternatively, security features may be formed by special colors, for example luminescent or optically variable colors, optical elements such as holograms, tilt images, kinegrams, lens or prism arrays, also guilloches, mottling fibers, security threads and others. Furthermore, it is also necessary that the value or security documents are easy to produce and that they can be detected by visually impaired persons.

In DE 33 14 327 C1 discloses a method of making a badge with highly stamped customer related data.

In EP 2 161 314 B1 For example, a method of generating an authentication mark on a recording medium is described. To generate the authentication mark, a marking material is first applied to an intermediate transfer element in an image area, so that a marking material image is produced. The marking material is one ultraviolet curable phase change ink composition. Thereafter, a predetermined amount of additional marking material is applied to the authenticating image area to increase the amount of marking material. Thereafter, the applied marking material is transferred from the intermediate transfer member to the recording medium. And finally, the marking material is cured on the recording medium so that the fixed marking material forms a tactually perceptible authentication mark.

Furthermore, in DE 10 2008 001 712 A1 a system for producing tactile structures on printed products specified. For this purpose, a sheet-fed press is used with multiple printing units. To create the tactile structures are on the signatures by radiation expandable pressure layers (bulking colors or paints), which is acted upon by means of laser marking devices.

Out DE 41 10 801 C1 a film printing method is known in which firstly the surface of the substrate to be printed is provided with an adhesive layer at the locations provided for printing, before a transfer film composed of a carrier film and a transfer layer adhering thereto via a release layer is placed under pressure on the substrate, and in which the transfer film adheres partially or flatly to the substrate. In order to produce a permanent connection between the substrate and the transfer layer, the substrate with the transfer layer thereon is exposed in a process step following the film support to a contact pressure which substantially exceeds the pressure during the film application.

In particular, for the production of tactile features, the known methods are extremely expensive. Especially in the case of EP 2 161 314 B1 described method for generating an authentication mark, it is necessary to apply the authentication material for each feature by means of a printing process on the substrate separately. In particular, the production of tactile structures in which a minimum height is required, the application is tedious and time-consuming. In addition, the materials required for these processes are expensive.

In US Pat. No. 7,410,551 B1 there is described a method according to the preamble of claim 1 which is a thermal marking method enabling the design of an article. For this purpose, a multilayer structure with a support layer, a decorative layer and arranged therebetween and curing radiation exposure paint layer is brought into contact with the object to be designed and the multilayer structure under pressure on the support layer at the point at which the decorative layer and the paint layer are transferred to the article should be pressed on the object. The support layer is peeled off and the lacquer layer is radiation-cured.

In EP 1 897 700 A2 there is provided a hot embossing method in which a transfer sheet of a support sheet is provided with a release liner on which a thin thermoplastic resin, then an aluminum sheet and thereon an adhesive layer are disposed. The transfer film is transferred to a substrate, for example a banknote. The transmission is limited to the range of pressure transmission by means of a pressure plate. The carrier layer with the non-transferred film components is removed again.

A security sticker from a stamping foil is in DE 10 2007 005 416 A1 specified. This sticker is also partially transferred by means of a stamp on a substrate. The present invention has for its object to provide a method for forming three-dimensional structures, which in particular should be palpable / felt, the is easy to carry out and that allows to achieve a sufficient fineness of the structures to be formed. The palpable structure should preferably be produced on a value or security document formed of polycarbonate or containing this material, in particular a polycarbonate card.

The above objects are achieved according to the present invention with the method of forming at least one three-dimensional structure on at least one surface of a substrate. The invention is particularly suitable for producing tactile structures on a value or security product. The value or security product may be a value or security document or security element, i. an element which is connected, for example, with an object to be protected against counterfeiting, forgery or falsification, for example a sticker, label or the like.

Insofar as the term "value or security product" is used in the description and in the claims of the present application, this includes, for example, a passport, identity card, driver's license or another ID card or an access control card, a vehicle registration document, vehicle registration document, visa, check, Means of payment, in particular a banknote, a check, bank, credit or cash card, customer card, health card, chip card, a company card, proof of entitlement, membership card, gift or shopping voucher, bill of lading or other proof of entitlement, tax stamp, postage stamp, ticket, (Spiel -) To identify a token, adhesive label (for example for product protection) or another ID document. Such products are value or security documents. As a product according to the invention is also a security element (transfer element) to understand that has a security feature according to the present invention and that can be permanently connected to an object to be protected, such as a sticker, label or the like. The product may be, for example, a smart card. The security or value document may be in ID 1, ID 2, ID 3, or any other format, such as a booklet form, such as a passport-like item. The value or security product is generally a laminate of several document layers, which are connected in register under the influence of heat and under increased pressure. These products should meet the standardized requirements, for example ISO 10373, ISO / IEC 7810, ISO 14443. The product layers consist, for example, of a carrier material which is suitable for lamination.

The value or security product can be formed from a polymer selected from a group comprising polycarbonate (PC), in particular bisphenol A polycarbonate or a polycarbonate, formed on the basis of a geminally disubstituted
Dihydroxydiphenylcycloalkane, polyethylene terephthalate (PET), its derivatives such as glycol-modified PET (PETG), polyethylene naphthalate (PEN), polyvinyl chloride (PVC), polyvinyl butyral (PVB), polymethyl methacrylate (PMMA), polyimide (PI), polyvinyl alcohol (PVA), polystyrene (PS ), Polyvinylphenol (PVP), polypropylene (PP), polyethylene (PE), thermoplastic elastomers (TPE), in particular thermoplastic polyurethane (TPU), acrylonitrile-butadiene-styrene copolymer (ABS) and derivatives thereof, and / or paper and / or cardboard and / or glass and / or metal and / or ceramics. In addition, the product can also be made of several of these materials. It preferably consists of PC or PC / TPU / PC. The polymers may be either filled or unfilled. In the latter case they are preferably transparent or translucent. If the polymers are filled, they are opaque. The above information relates both to films to be joined together and to liquid formulations applied to a precursor, such as a protective or topcoat. The product is preferably prepared from 3 to 12, preferably 4 to 10, films. The films may also carry print layers. A laminate formed in this way can finally be coated on one or both sides with the protective or topcoat or with a film. In particular, the film may be a volume hologram, a film with a surface hologram (for example a kinegraphic element) or a scratch-resistant film. Overlay layers formed in this way protect a security feature arranged underneath and / or give the document the required abrasion resistance.

As used in the specification and claims of the present application, the term "pattern" is to be understood as meaning a somewhat distributed distribution of tactile impression-imparting elements on one or more surfaces, resulting in a self-contained representation, for example Image, picture element, characters, including Braille, in particular Braille, or an alphanumeric character, symbol, crest, line, formula or the like. The pattern is formed by the claimed three-dimensional structures. The structures may additionally give an optical impression, in particular if they have a contrasting color, including black, gray or white, to the color of the substrate in the region of the elevations or depressions of the substrate. For this purpose, the material forming the three-dimensional structures is colored by means of customary colors (dyes, pigments).

As far as in the description and in the claims of the present application, the term 'pattern element' is called, it is to be understood as a component / element of a pattern, wherein the pattern elements can be separated from each other or merge seamlessly into each other. A pattern element serves as the smallest structural element for forming the pattern, with all pattern elements forming the pattern. The pattern element is a three-dimensional structure in the form of a raised or indentation on a substrate surface. The pattern elements, when separated from each other, may each have a circular (dot-shaped), rectangular, square, hexagonal or other shape and a size / diameter of, for example, 1 to 100 μm. The pattern elements can also merge into each other, so that no regular structural elements are formed. For example, a Braille character corresponding to an alphanumeric character may represent a pattern, while the individual character elements constituting a Braille character in the known 3x2 matrix each form a pattern element.

As far as the terms 'raster' and 'rasterized' are used in this description and in the claims, this is to be understood as a decomposition of an image into individual pattern elements, which are typically arranged regularly, for example in lines or in another regular arrangement , The pattern elements may be arranged, for example, in a honeycomb arrangement or in a row arrangement with pattern elements offset from one another or not offset from one another.

As far as in the description and in the claims a term in the singular is called, for example 'foil element', 'three-dimensional structure', 'surface of the substrate', etc., the term in the context is meant simultaneously in the plural, so for example, 'foil elements' , 'three-dimensional structures', 'surfaces of the substrate', etc., unless expressly stated otherwise. The same applies in the opposite case.

1. a. Bereitstellen des Substrats sowie eines strukturbildenden Materials in Form einer (strukturbildenden) Folie,
2. b. Mechanisches Trennen mindestens eines Folienelements von solchen Folienteilbereichen, die dem mindestens einen Folienelement nicht entsprechen (d.h. von dem Rest der Folie), und
3. c. Unlösbares (untrennbares) Verbinden des mindestens einen Folienelements mit der mindestens einen Oberfläche des Substrats in jeweils einem Adhäsionsbereich des Substrats, wobei das mindestens eine Folienelement durch lokales Applizieren eines Löse- oder Quellmittels für das strukturbildende Material der Folie und/oder für das Material des Substrats in dem mindestens einen Adhäsionsbereich mit der mindestens einen Oberfläche des Substrats unlösbar verbunden wird.

The method according to the invention serves to form at least one three-dimensional structure on at least one surface of a substrate. It comprises the following process steps:

1. a. Providing the substrate and a structure-forming material in the form of a (structure-forming) film,
2. b. Mechanically separating at least one film element from those film part regions which do not correspond to the at least one film element (ie from the rest of the film), and
3. c. Insoluble (inseparable) bonding of the at least one film element to the at least one surface of the substrate in each case an adhesion region of the substrate, wherein the at least one film element by locally applying a solvent or swelling agent for the structure-forming material of the film and / or for the material of the substrate in which at least one adhesion region is non-detachably connected to the at least one surface of the substrate.

As a result, the at least one film element forms the at least one three-dimensional structure on the at least one surface of the substrate.

The above process steps may all take place simultaneously, or some of these process steps may be performed simultaneously and others in succession, or all process steps may be performed sequentially. If some or all of the process steps are performed one after the other, then in one of many ways of successive steps they may occur in sequence in a particular order. For example, the method steps (b) (mechanical separation of at least one film element of film subregions that do not correspond to the at least one film element) and (c) (indissolubly bonding the at least one film element to the at least one surface of the substrate in each adhesion region of the substrate) according to the invention preferably take place simultaneously after the substrate and the structure-forming film has been provided (method step (a)), when the mechanical separation is carried out for example in the sense of a stamping process. Alternatively, the method steps (b) and (c) after the provision of the substrate and the structure-forming film (method step (a)) but also take place sequentially and that by first the film element is mechanically separated from the film member not corresponding film portions (method step (b )) and this separated film element is then inextricably bonded to the substrate surface in the adhesion region (process step (c)). If at least some of the mentioned method steps are carried out successively, they are preferably run through in the above-mentioned order.

The three-dimensional structure forms a security feature on the value or security product. This security feature can be tactile. But there is also the possibility that it is not tactile. If it is palpable, it must have a minimum height. For example, the height may be at least about 30 μm, more preferably at least 100 μm, most preferably at least 300 microns, amount. Suitably, the security feature is not higher than a few millimeters, for example not higher than 3 mm, preferably not higher than 2 mm, more preferably not higher than 1 mm and most preferably not higher than 750 μm. In this case, a person can feel the structure. For example, the structure may be in the form of braille, in particular braille. However, it is also possible to form tactile structures with a different coding, for example a regular pattern or a certain roughness in the form of unevenly (randomly) arranged structures. All of these structures allow a person to perceive the structure by palpation. If the three-dimensional structures are not palpable because they do not have sufficient height, for example about 150 μm, for the scanning against the substrate surface, they can be detected by machine, for example with a scanning device or optically by means of grazing illumination.

In particular for the formation of structures perceptible by a human being, the method according to the invention is well suited, since it is very easy to carry out and does not require expensive and expensive materials and devices for applying the materials. To produce the structures, these are formed from the structure-forming material by completely transferring the material in the area to be transferred (adhesion area) to the substrate and fixing it there. The fixation leads to a permanent connection of the transferred material element with the substrate surface. For fixing a force is applied to the material element (pressure application, impact method) to impose it on the substrate surface. In contrast to the thermal transfer printing method in which a temperature-sensitive ink-coated transfer ribbon is interposed between the substrate and a thermal printhead and only the ink is transferred from the transfer ribbon to the substrate due to thermal and mechanical stress by the thermal printhead, but not the color-carrying ribbon , the structure-forming film arranged between a tool and the substrate is completely transferred onto the substrate in the case according to the invention. The process corresponds to a punching process in which the film element to be transferred is punched out of the structure-forming film (ie completely removed) and transferred to the substrate. This enables a very precise generation even of very small film elements, which are placed on a precisely positioned position on the substrate and connected there with it inseparably. The process is consequently fast, since the structural height required for the production of tactile three-dimensional structures is achieved by a simple choice of the film thickness suitable for this purpose. The material will regardless of the target height of the structure, it is preferable to transfer it to the substrate surface in one step, although it is also possible to build a second structure having a second height thereon after creating a first structure having a first height thereon, the first height and the second height being equal or may be different to either increase the feature height or to create a more complex structure. It is therefore not necessary to use the structures as in the case of EP 2 161 314 B1 to build successive process described. An advantage over an embossing method is also that even sensitive substrates can be easily provided with the three-dimensional structures: For example, it would not be possible with a stamping process, a value or security document that contains an internal electrical circuit, which may also include an electronic semiconductor device to structure with a stamping process. Because the circuit and in particular the electronic semiconductor device and their connections can be damaged or even destroyed in this process. By contrast, the process according to the invention is much gentler and does not affect these components.

The tool (s) used to transfer the film elements to the substrate may be configured to screen the film elements, ie, to punch and transfer them in small pattern elements. In this way, any three-dimensional patterns can be generated on the substrate. Therefore, it is possible to produce the three-dimensional structure not only in a single configuration for a larger totality of substrates common to all of these substrates but also to form an individual configuration of the three-dimensional structure for each individual substrate. Thus, the three-dimensional structures can also be embodied in the form of individualizing, in particular personalizing, markings, ie in the form of markings that reproduce, for example, individualizing data of a person or a thing to which the value or security document is assigned. For example, in this way, the name or another characteristic of the person in plain text or in coded form may be displayed in three dimensions. As such, the three-dimensional pattern can encode information. For example, the three-dimensional marking can be represented by alphanumeric characters or, more preferably, in Braille, in particular Braille. Thus, the three-dimensional structure can represent an authentication feature. Furthermore, it is also possible to provide an entire group of similar value or security documents with the same structure, for example Banknotes with a value label. In addition, the three-dimensional structure may also be a verification or authentication feature.

In a preferred development of the present invention, the at least one film element in the non-detachable connection with the at least one surface of the substrate is in direct contact with the at least one surface of the substrate. In the transfer of the film element to the substrate surface, therefore, no adhesion promoter (adhesive) or any other additional substance is provided between the film element and the substrate surface for connection to the substrate. The film itself has in this preferred embodiment of the invention, at least on the side no adhesion promoter, which is brought into contact with the substrate. Thus, the film element comes in direct contact with the substrate surface. The film element lies flat on the substrate surface after the transfer. The avoidance of additional material between the film element and the substrate surface allows inter alia a better and stronger connection of the film element on the substrate surface. Preferably, a monolithic connection is formed between the two connection partners, i. a connection in which the individual connection partners no longer exist separately after the connection has been formed, because the two connection partners are no longer separated by an interface. Such an intimate connection is achieved in particular by a firm contact pressure of the film element on the substrate surface.

In a further preferred development of the present invention, the at least one film element is non-releasably connected by local pressing in the at least one adhesion region to the at least one surface of the substrate and also by heating. This is particularly advantageous if the structure-forming material is a thermoplastic material, so that it melts at least partially when heated. For example, the tool used for pressing and / or separating can also be used for the heating. The tool is supplied with heat, which then passes it on to the film element, or the tool is designed to generate the heat itself, for example via a resistance heater or an ultrasonic vibration device. Alternatively, it is also possible to use a separate tool for the heating, for example an electromagnetic radiation source, for example a laser device, whose radiation is absorbed in the film element so that it heats up. For this purpose, the film element may contain special absorber agents, in particular substances selectively absorbing in the infrared spectral range (thermosensitive substances). These are preferably located in a region in the structure-forming film or the film element, which is arranged adjacent to the contact side with the substrate surface. In this case, the film element may first be brought into contact with the substrate surface and then the contacted film element may be heated and optionally additionally pressed onto the substrate surface. Before or subsequently, the film residue can be mechanically separated from the area of the structure-forming film corresponding to the film element. If the heating takes place by means of electromagnetic radiation, it can be passed through a contact pressure element. The pressing element must be transparent / translucent for the electromagnetic radiation for this purpose.

According to the invention, the at least one film element is permanently connected in the at least one adhesion region by local application of a chemical agent which acts as a solvent or swelling agent for the structure-forming material of the structure-forming film and / or as a solvent or swelling agent for the substrate material. Instead of, or in addition to, heat application used in the above-described procedure for non-releasably bonding the film element to the substrate surface, this compound can be prepared by the chemical action on the contacted surfaces of the structure-forming film and the substrate. For this purpose, the solvent or swelling agent can be matched to the film material and / or to the substrate material. If a polycarbonate-containing material is preferably used for the structure-forming film or the film is formed from a polycarbonate, can be used as a solvent or swelling agent one of in DE 10 2007 052 947 A1 specified solvents are used, which are specified there as a solvent for the existing based on a polycarbonate ink (corresponding to the specified there component B). Therefore, this document is hereby incorporated in full in the disclosure of the present application, but at least to the extent of the solvents mentioned there. The following solvents or swelling agents are therefore used with particular preference: aliphatic, cycloaliphatic, aromatic hydrocarbons and liquid organic esters.

The solvent or swelling agent is applied by a tool to the film element, preferably when the latter is already in contact with the substrate surface. By solving or swelling of the film material, this connects in an excellent manner with the material of the substrate on the surface thereof. The tool used to press the Foil element and / or for mechanically separating the film element from the rest of the structure-forming film, may additionally be adapted to apply the solvent or swelling agent. For this purpose, this tool has outlet openings for the chemical agent, for example nozzles, which are connected to a reservoir for the solvent or swelling agent.

In order for the solvent or swelling agent to reach the contact surface between the film element and the substrate surface, it may furthermore preferably be provided that the structure-forming material of the film has cavities which completely penetrate the film. These cavities are designed so that a solvent or swelling agent, which is applied to a film side, which is opposite to a contact side of the film with the at least one surface of the substrate, can pass through the film and reach the contact side of the film.

The cavities can be introduced during the production of the structure-forming film or only afterwards.

In the former case, the film may be provided during extrusion with a blown material, the outgassing at elevated temperature and produces the cavities. Alternatively, inorganic or organic materials which have a porosity may also be incorporated in the polymer material of the transfer film, for example silicon dioxide or aluminum oxide, which may be present in the form of nanoscale particles. Alternatively, larger particles with correspondingly small cavities can be used, for example zeolites. Such filled materials are exemplary in DE 10 2010 035 890 A1 specified. This document shows a process for producing a microporous film. In this case, a particulate material is extruded into a film. The particles have defined cavities. It may be, for example, zeolites or fullerenes. According to another in DE 10 2010 035 890 A1 specified manufacturing method, a suspension of polymer particles, such as PC particles, applied to a film carrier. The liquid components of the suspension are then evaporated so that the remaining PC particles combine to form a porous film. Therefore, this document is hereby incorporated in full, at least in any case with regard to the production of such materials in the disclosure of the present application. Alternatively, a foamed composition of a resin emulsion may be used. Such a manufacturing method with an acrylic ester resin is in DE 600 36 341 T2 described. That's why this one too Document hereby incorporated in full, at least in any case with regard to the production of such a polymer material, in the disclosure of the present application. Insofar as polymers other than acrylic ester resins are used for such a process, for example PC or PET, appropriate adjustments to be made by a person skilled in the art are required. These materials can be made using the resin emulsion as well as foaming agents, foam stabilizers and thickeners.

If the cavities are formed only after the formation of the structure-forming film, they can be produced by perforation processes, for example by laser drilling (laser ablation, either thermally with a CO ₂ laser or by photolytic decomposition of the polymer material with a UV (excimer) laser. For example, the film material may be porous.

The cavities may be formed by holes, depressions, cavities, channels, pores, recesses, cavities and the like. In particular, the cavities have a size in the micrometer range, i. the diameter / thickness of the cavities is in the range from 1 μm to 1000 μm, preferably in the range from 1 μm to 500 μm and very particularly preferably in the range from 1 μm to 100 μm. In principle, the cavities can also be smaller: their size can be, for example, at least 50 nm and more preferably at least 100 nm and a maximum of 1000 μm, more preferably a maximum of 500 μm and most preferably a maximum of 100 μm.

In a further preferred embodiment of the present invention, the structure-forming material according to a matrix (a grid) on the at least one surface of the substrate is connected pointwise inseparable, so that the film elements corresponding to these dot surfaces are transferred to the substrate surface. This makes it possible to form any three-dimensional structures on the substrate surface.

In a further preferred development of the present invention, the structure-forming film has a thickness of 50 to 250 μm. However, the film thickness can also be larger or smaller, that is to say for example at least 30 μm or at least 75 μm or at least 100 μm or at least 250 μm or at least 500 μm. Regardless of the minimum thickness values mentioned above, the film thickness can also be a maximum of 3000 μm or a maximum of 1000 μm or a maximum of 500 μm or a maximum of 250 μm or a maximum of 100 μm. The maximum film thickness is essentially limited by the fact that arbitrarily thick film elements from the structure-forming Material can not be separated out with the desired fineness. The structures made with such a film accordingly have the stated height. Structures formed with such a height are tangible.

In a further preferred development of the present invention, the film has at least one dye or at least one pigment. The dye or pigment may preferably be absorbing and / or luminescent in the visible spectral range. The dye or the pigment can be in the film or as a layer, for example as a print layer, on the film.

In a further preferred development of the present invention, the structure-forming film has regularly arranged thin regions, so that the at least one film element is mechanically separated along thin regions which surround the film element from film subregions which do not correspond to the at least one film element (the film residue). As a result, the film element can be separated very easily and precisely from the rest of the structure-forming film because the thin areas represent desired separation points. Between the thin areas are raised areas. The grid of the thin regions and the raised regions preferably extends over the entire surface of the structure-forming film. By providing the film with thin areas, which represent a weakening of the film material, the film can preferably tear along these areas, so that the film element can thus be mechanically separated easily. As a result, a controlled shaping of the film elements is also achieved. If there are no such thin regions, the mechanical separation could be a problem, especially if the structure-forming film is relatively thick. If more complex-shaped film elements are to be connected to the substrate surface, the thin areas allow the formation of a more regular edge profile of the film elements, because the film elements are separated along the thin areas acting as tear lines. If the thin regions are arranged, for example, in a hexagonal grid (honeycomb structure), a regular edge structure of the film elements corresponding to this grid results on the substrate surface. Through targeted shaping of the tear lines, therefore, different edge structures are available. This variability can be used to identify the particular document or document type because the edge structure of the transferred sheet elements can be analyzed. The thin areas preferably form in a structure-forming film a multiplicity of bordered grid cells, which are particularly preferred are arranged regularly. The film elements may be formed by one or more such grid cells.

In a preferred first embodiment of this development of the present invention, the thin areas in producing the structure-forming film material are formed by a material structure in the areas outside the thin areas, i. in the raised areas, generated. In a preferred second embodiment of this development, the thin areas are produced only after the production of the foil material by material removal or material deformation. These approaches can also be combined. If the thin areas are only produced after the production process by material deformation, a stamping method can be used for this purpose in a further development of the present invention. If the thin areas are produced by material removal after the production process, a chemical etching method or a corona etching method can be used for this purpose in an alternative development. If the thin regions are already produced before the production process, a further printing process, for example a screen printing process, can be used for this purpose in a further development of the present invention. The printing process produces a reinforced layer outside the thin areas by applying material. As a result, the thickness of an application (foil) element is locally reduced in the thin areas.

If the thin areas are produced by means of a printing process by applying material outside these areas, for example a by means of electromagnetic radiation, such as UV radiation, curable polymer, such as a Cyanoacrylatlack be applied in a layer, so that sets a reduced thickness of the application element in the thin areas ,

If the thin regions are produced by material deformation by means of an embossing process, the structure required for producing the thin regions can be, for example, by means of ultrasound and / or by introducing heat and temperature increase and applying a pressing pressure with a tool, for example an embossing punch or a stamping plate / embossing plate be pressed into a fusible polymer layer, such as polycarbonate, and the structure produced subsequently be fixed by cooling or by curing of the polymer caused by electromagnetic radiation. For example, the polymer layer can melt locally. For example, a thermoplastic Polymer layer can be used, which is molded under temperature increase by means of the tool.

If the thin regions are formed by material removal after fabricating the pattern-forming film, such as by a chemical etching process, an etchant may act, for example, on a metal layer that is part of the pattern-forming film by thinning the metal layer in the areas where the metal layer is thinned should be removed locally (demetallization). For this required methods and, for example, chemical etchants are known in the art. If the material to be thinned is not a metal, but a layer or foil of another material, the etchant must be adjusted accordingly. As a further alternative for a removal method for producing the thin areas, the corona etching method can be used. Other ablation methods are evaporation (for example with an IR laser), laser ablation by decomposition of the material (for example with a UV laser) and chemical etching with suitable etchants.

The thin regions preferably do not extend completely through the structure-forming film. They are two-dimensionally rastered, ie formed in a preferably regular two-dimensional arrangement. Accordingly, the intervening raised areas are regularly, ie rasterized arranged. The thin areas may be formed, for example, by continuous trenches or by mutually spaced depressions or perforations. The trenches may additionally have perforations. The thin areas can either be formed exclusively by trenches, for example, have a uniform depth, or in addition to trenches with uniform depth perforations that completely penetrate the material of the film. Alternatively, there may be only perforations or trenches of varying depth or other types of thin areas. The cavities, recesses, recesses, recesses, openings, hollows and the like forming the thin regions are preferably in a regular one-dimensional or two-dimensional arrangement. For example, the thin areas may be formed in the form of a square, rectangular, parallelogram-like, hexagon-shaped, or even curved, borderline groups crossing each other at a predetermined arbitrary angle. Grid cells are formed by the grid of the thin areas (grid cells between the thin areas form pixels in a raised form, so that a pixelated film formed by the thin areas in grid form is formed). The pixels can be 'punctiform' or in the form of stripes or in some other form raised above the thin areas. The minimum dimensions of the grid cells are predetermined by the desired fineness of the film element. The more precisely the contours of the film element are to be traced, the finer the grid of the thin areas must be formed. For example, the grid has raster cells with lateral dimensions of 50 μm to 500 μm, preferably of 70 μm to 200 μm. The width of the thin areas is irrelevant to their function of weakening the material of the structure-forming film. However, the width is given by the chosen production method. The depth of the depressions or similar is determined by the total thickness of the film. The residual thickness (total thickness of the film minus the total depth of the recesses [in the case of thin regions on both sides of the film minus the sum of the mutually opposite recesses]) should be so small that the film preferably tears easily only in the thin regions. For example, the residual thickness may be 5 μm to 200 μm, more preferably 30 μm to 100 μm.

In a further preferred development of the present invention, the structure-forming material is polycarbonate or contains at least polycarbonate. Alternatively, the structure-forming material may also be or contain PET.

In a further preferred embodiment of the present invention, the substrate is a value or security product or a precursor of a value or security product.

Since the process steps are successively executable, various tools can be used to perform them: To apply a pressure for the non-detachable connection of the film element with the substrate surface, a thermal comb can be used, as it is also used in thermal (transfer) pressure. A thermal ridge has a plurality of juxtaposed pistons, which are preferably arranged equidistant from each other. Alternatively, a printhead used as in a conventional dot-matrix printer may be used. In particular, for the generation of Braille font, the pixels are arranged in a 3 x 2 matrix, for example, for each line three superimposed printing tools, such as stamps are provided. The individual film elements are separated by means of such printing tools preferably with a punching process of the structure-forming film (isolated). The individual tools of the thermal ridge or print head can be controlled individually. Alternatively, of course, individual dies or stamping plates or sheets can be used. Preferably These are heated. If the fixation of the film elements to be made by electromagnetic radiation, this transparent / translucent tools are used. If the heat is to be supplied via vibration devices, a corresponding ultrasound generator is to be provided, the ultrasound energy of which is mechanically coupled into the tools. A targeted supply of a solvent or swelling agent for connecting the film element to the substrate surface is to be provided at the location at which the film element is pressed onto the substrate surface. For this purpose, a respective suitable dispenser is available. The supply of the solvent or swelling agent is also controlled separately, unless the supply is possible via capillary forces.

For the application of film elements to different locations on the substrate, a device suitable for this purpose has a holder of the substrate and optionally a feed device for the substrate and a movement device which allows a relative movement between the substrate and the print head or stamp.

Fig. 1:

eine schematische isometrische Darstellung eines Wert- oder Sicherheitsdokuments in Form einer Identitätskarte;

Fig. 2:

eine schematische Schnittansicht der Identitätskarte entlang der Linie I-I in einem Ausschnitt;

Fig. 3:

eine schematische Schnittdarstellung eines Substrats und einer darüber angeordneten strukturbildenden Folie zusammen mit einem Werkzeug zum Übertragen und Fixieren eines Folienelements auf der Substratoberfläche; (A) Anfangszustand des Substrats und der Folie mit einem Werkzeug in der Ausgangsstellung; (B) das Werkzeug drückt die Folie im Bereich des Folienelements gegen die Substratoberfläche; (C) das Werkzeug stanzt das Folienelement aus der Folie aus, drückt das Folienelement gegen die Substratoberfläche und fixiert es auf dieser; (D) das Werkzeug fährt in die Ausgangsstellung;

Fig. 4:

eine schematische Querschnittsansicht des Werkzeuges mit dem ausgestanzten Folienelement auf dem Substrat in einer ersten Ausführungsform (Wärmeapplikation);

Fig. 5:

eine schematische Querschnittsansicht des Werkzeuges mit dem ausgestanzten Folienelement auf dem Substrat in einer zweiten Ausführungsform (Applikation eines Löse- oder Quellmittels), erste Variante;

Fig. 6:

eine schematische Querschnittsansicht des Werkzeuges mit dem ausgestanzten Folienelement auf dem Substrat in der zweiten Ausführungsform (Applikation eines Löse- oder Quellmittels), zweite Variante;

Fig. 7A

eine schematische Querschnittsansicht einer pixelierten Folie mit durch Dünnbereiche getrennten erhabenen Bereichen;

Fig. 7B, C

schematische Draufsichten auf ein sukzessive mit Rasterzellen versehenes Substrat;

Fig. 8

schematische Draufsicht auf eine pixelierte Folie;

Fig. 9

schematische isometrische Darstellung der Übertragung von einzelnen Rasterpunkten von einer strukturbildenden Folie (Fig. 9A) auf ein Substrat (Fig. 9B);

Fig. 10

schematische Darstellung der Herstellung einer mit Kavitäten versehenen strukturbildenden Folie.

The present invention is explained in more detail below with reference to figures, wherein the illustrated examples are merely exemplary in nature and do not represent a limitation on the scope of the described invention. They show in detail:

Fig. 1:

a schematic isometric view of a value or security document in the form of an identity card;

Fig. 2:

a schematic sectional view of the identity card along the line II in a section;

3:

a schematic sectional view of a substrate and an overlying structure-forming film together with a tool for transferring and fixing a film element on the substrate surface; (A) initial state of the substrate and the film with a tool in the home position; (B) the tool pushes the film in the region of the film element against the substrate surface; (C) the tool punches the foil element out of the foil, presses the foil element against the substrate surface and fixes it thereon; (D) the tool moves to the starting position;

4:

a schematic cross-sectional view of the tool with the punched-out sheet member on the substrate in a first embodiment (heat application);

Fig. 5:

a schematic cross-sectional view of the tool with the punched-out film element on the substrate in a second embodiment (application of a solvent or swelling agent), the first variant;

Fig. 6:

a schematic cross-sectional view of the tool with the punched-out film element on the substrate in the second embodiment (application of a solvent or swelling agent), second variant;

Fig. 7A

a schematic cross-sectional view of a pixelated film with separated by thin areas raised areas;

Fig. 7B, C

schematic plan views of a successive gridded substrate;

Fig. 8

schematic plan view of a pixelated film;

Fig. 9

schematic isometric representation of the transmission of individual halftone dots of a structure-forming film ( Fig. 9A ) on a substrate ( Fig. 9B );

Fig. 10

schematic representation of the preparation of a provided with cavities structure-forming film.

In the figures, like reference numerals designate elements having the same function or like elements.

The substrate 100 to be provided with a three-dimensional structure may be a value or security document or a security element, which may be applied, for example, as a sticker to an article to be secured, for example a value or security document and firmly connected thereto. The security or security document may be a personal document such as a passport, identity card, access badge or the like, a check card or banknote or other document. All examples below are described as representative of other types of documents based on such a card.

In Fig. 1, 2 is representative of other such products, an identity card 100 shown, which has been assembled, for example, as a laminate of a plurality of inner polymer layers 140. For example, the polymer layers may consist of PC and / or PET. The individual layers may be unfilled or filled with fillers. In the latter case, they are opaque, otherwise transparent. The layers may preferably be connected together in such a way that they form a monolithic block which can not be split in practice. In Fig. 2 For illustration only, the layers still separated before lamination are shown visibly. In the finished laminate, the interfaces are no longer visible. The outer layers 150 of the card may consist of a protective lacquer which has been applied to the card after lamination. The protective varnish is transparent, so that underlying information is visible from the outside.

The card 100 has an upper side 101 and a lower side 102. On the top there are a face image 110 of the card owner and four data fields, namely a first data field 120, a second data field 130 with card and owner data in plain text and a third data field 125 and a fourth data field 135 with the card and owner data in Braille, for example Braille. The third data field indicates the data of the first data field in braille, and the fourth data field also indicates the data of the second data field in braille. The data in the first and in the second data field are produced by printed layers which lie on an outer layer of the document, but immediately below the outer protective lacquer layer 150. Braille is formed by the method according to the invention.

• Ausgehend von dem Substrat 100 und einer strukturbildenden Folie 200, beispielsweise einer beispielsweise 150 µm dicken weißen opaken PC-Folie, die oberhalb der Oberfläche 101 des Substrats und im Wesentlichen parallel zu dieser angeordnet ist, wird ein Stanzwerkzeug 300 oberhalb der Stelle auf der Substratoberfläche in Position gebracht, auf der ein erhabener Rasterpunkt 400 (Fig. 3D), beispielsweise mit kreisrunder Fläche auf der Substratoberfläche angeordnet und fixiert werden soll (Fig. 3A). Dieser Anfangszustand entspricht Verfahrensschritt (a) des erfindungsgemäßen Verfahrens (Bereitstellen des Substrats sowie eines strukturbildenden Materials in Form einer Folie).

The sequence of the method according to the invention is shown schematically in FIG Fig. 3 reproduced:

• Starting from the substrate 100 and a structure-forming film 200, for example, a, for example, 150 micron thick white opaque PC film, which is disposed above the surface 101 of the substrate and substantially parallel to this, a punching tool 300 is above the location on the substrate surface in Position on which a raised grid point 400 ( Fig. 3D ), for example, with a circular surface on the substrate surface to be arranged and fixed ( Fig. 3A ). This initial state corresponds to process step (a) of the process according to the invention (provision of the substrate and of a structure-forming material in the form of a film).

In order to transfer a film element 210 of the structure-forming film 200 onto the substrate surface 101, the stamping tool 300 is then lowered onto the structure-forming film so that it presses the film down onto the substrate surface ( Fig. 3B ). By exercising a sufficient punching pressure P on the film, the punching tool punches the foil element 210 out of the foil so that the foil (the foil residue 230) is again transferred into the spaced-apart state ( Fig. 3C ). This process corresponds to process step (b) of the process according to the invention (mechanical separation of the film element from film subregions which do not correspond to the at least one film element).

The film element 210 is located between the end face 310 of the punching tool and the substrate surface 101. By exerting the pressing pressure P on the film element 210 and by heat generation W by the tool ( Fig. 4 ) and / or inventive application of a solvent or swelling agent M through the film element ( Fig. 5 . 6 ), the film element is fixed on the substrate surface, ie there inextricably linked. This process corresponds to process step (c) of the process according to the invention (non-detachable bonding of the film element to the surface of the substrate 100 in an adhesion region 160 of the substrate). This connection takes place by direct contact between the material of the film element and the substrate surface, without there being a bonding agent therebetween. Finally, the tool is lifted off the fixed film element again and transported to the starting position ( Fig. 3D ).

For non-detachable fixing of the film element 210 on the substrate surface 101, therefore, in addition to the application of the mechanical pressing pressure P, heat W can be transferred to the film element ( Fig. 4 ). For this purpose, the tool may be designed to generate the heat required for this purpose, for example via a resistance heater or by means of an ultrasonic generator (a piezoelectric crystal) (not shown), and to transfer to the film element. If the structure-forming film 200 and thus the film element consists of a thermoplastic material, for example of PC or PET, this is at least partially melted by the temperature increase generated during the heat transfer and in this way bonds firmly to the substrate surface. This process can be further assisted by the substrate 100 also containing on the surface a thermoplastic material which at least partially melts under the conditions used.

In accordance with the invention, instead of heat W, a solvent or swelling agent M is applied. The structure-forming film 200 is in this case provided with through-passing cavities 220 which, for example, are laser-ablated in the structure-forming film have been introduced. As a result, a solvent or swelling agent applied from above can penetrate through the film element 210 so that it reaches the underside 215 of the film element, ie, up to the contact surface between the film element and the substrate surface 101 (FIG. Fig. 5 ). After the film element has been punched out by means of the punching tool 300, the solvent or swelling agent is injected from the tool into the film element, for example through corresponding nozzle openings 320 in the stamping surface 310. The solvent or swelling agent penetrates through the cavities to the underside 215 of the film element and connects this there with the substrate 100, while the film element is pressed firmly onto the substrate surface. If the film element as well as the substrate consist of or contain PC, the solvent or swelling agent may be, for example, methyl acetate.

Instead of separately introduced cavities 220, through cavities, openings, channels or the like produced in a different manner may be provided in order to guide the solvent or swelling agent M from the top to the bottom 215 of the film element 210. Such an example in Fig. 6 shown. The film element 210 used there is formed from a multiplicity of grains, for example granules, which are joined together in a baking process. At the grain boundaries are still left cavities, which allow the passage of the solvent or swelling agent. This foil element is porous.

In yet another embodiment, the film may also be present as an open-pored foam. The preparation of such materials is known.

In order that the film element 210 can be separated from the film residue 230 without problems and, in particular, with good edge sharpness, the structure-forming film can also be pixelated, i. be provided with thin areas.

A structure-forming film 200 according to a first embodiment of this development of the present invention is in Fig. 7A shown in the clipping. The film has a carrier layer 240 and raised regions (raster cells) 250, which are separated from one another by thin regions 260. Furthermore, a separating layer 295 is located between the carrier layer and the raised areas. The carrier layer may be, for example, a PET film and the separating layer may be a silicone layer. The raised areas may be formed of PC, for example. One or more raster cells finally form the film element 210 to be transferred to the substrate 100. The carrier layer and the separating layer may be in the form of a band be. Alternatively, the structure-forming film can also be formed without a separating layer, so that together with the raised areas, these bearing areas of the carrier layer are also punched out and transferred to the substrate surface.

So that the film element 210 is transferred to the substrate 100 as precisely as possible in the desired pattern structure, the thin regions 260 are provided. The thin areas define the grid cells 250 lying between them. In the present case, the thin areas on the film 200 form a honeycomb-like structure of narrow trenches 260 with the grid cells 250 arranged therebetween (pixelized film). The thin areas penetrate the film element completely, but do not reach into the carrier layer and possibly the separating layer ( Fig. 7A ). The thin areas are formed in the film in a regular arrangement, namely in a two-dimensional gridded arrangement. A possible example of such a pixelated film is in Fig. 8 shown. In this example, the spacing of adjacent thin areas and the size of the grid cells are constant. In order to produce the raised areas and thin areas on the carrier and the separating layer, the structure-forming material can be structured, for example, in an embossing process. Alternatively, the structure-forming material in the thin regions may be partially removed, for example by a polymer etching process. For example, polyimide can be removed with an alkaline solution. For this purpose, an etching mask is used which prevents polymer material from being removed even in the areas which are not to be removed. The etching masks are removed again after the generation of the thin regions.

The raised areas 250 of the Fig. 7A shown film 200 are then as in Fig. 3 shown brought into contact with the substrate 100. The backing sheet 240 faces up to the tool 300, and the raised portions are aligned with the substrate surface 101. After separating a raised area from the foil remainder 230 and fixing this area on the surface 101 of the substrate 100, a pixel or halftone dot 400 results there (FIG. Fig. 7B ). After applying another pixel, a substrate with two pixels 400, 400 'is obtained ( Fig. 7C ). Alternatively, to form a film element 210, it is of course also possible for a plurality of raised areas to be applied simultaneously to the substrate surface, which together form a film element.

The use of a pixelated film has the additional advantage for the method according to the invention, in which, in addition to the pressing pressure by the tool, a solvent or swelling agent to insoluble Connecting the film element is supplied to the substrate surface, that the solvent or swelling agent can easily penetrate through the thin areas in the film layer. However, so that the solvent or swelling agent can penetrate to this layer, also the carrier layer 240 and the separating layer 295 are provided with cavities.

Thus, only the parts of the patterning film 200 adhere to the substrate surface 101, which are in the adhesion region 160 and which correspond to the pattern to be formed.

In a further embodiment of this development of the present invention, a structure-forming film 200 is formed which has thickened regions 250 of a polymer film, for example a PC film, and intervening thinner regions 260 in a specific pattern ( Fig. 9 ). The material of the thickened regions may be substantially the same as the material of the polymer film. For this purpose, the material for the thickened areas, for example in the form of a paint can be printed on the polymer film, for example by a screen printing process. The raised areas serve to form surveys 400 for braille on a value and / or security document. For this purpose, the grid spacing of the elevations corresponds to the spacing of the dots in the Braille dot pattern which is customary for Braille writing. For repetitive plotting of dot patterns on documents, such a tape may be produced ( Fig. 9A ).

The tape is pressed with the elevations on the surface 101 of the substrate 100 and non-detachably connected to the substrate by means of heat and / or under the action of a solvent or swelling agent or in some other way. A foil element 210 in this case corresponds exactly to a survey. This is located in an adhesion region 160 on the substrate surface. The material of the structuring film between the bumps, i. in the thin areas, ruptures relatively easily, since the polymer film itself can be relatively thin. Therefore, the film elements in the entire film thickness including the elevations are transferred to the substrate surface. Since relatively thick point elevations 400 can be formed on the substrate surface with the film, a tactile element, in particular information in the form of Braille writing, can be generated on the substrate surface in this way.

• Eine Suspension 280 von Polymerteilchen 270, beispielsweise PC-Teilchen, wird auf einen umlaufenden Folienträger 500, beispielsweise auf eine Metallfolie, aufgegossen. Anschließend werden alle Flüssigkeitsanteile 290 der Suspension verdampft, sodass sich die zurückbleibenden Polymerteilchen miteinander verbinden und sich die mit durchgehenden Kavitäten 220 zwischen den Polymerteilchen versehene strukturbildende Folie 200 ausbildet. Anschließend kann die strukturbildende Folie von dem Folienträger abgehoben werden, sodass eine durchgehende Kavitäten aufweisende Polymerfolie gebildet wird. Die Polymerteilchen können in der Suspension teilweise angelöst sein, um beim Verdunsten der flüssigen Bestandteile ein Anhaften der Polymerteilchen aneinander zu verbessern. Außerdem können die Polymerteilchen an der Oberfläche reaktive Gruppen aufweisen, um eine nachträgliche Vernetzung zu bewirken, sodass der Schichtbereich einen festen inneren Zusammenhalt hat.

In Fig. 10 FIG. 2 schematically illustrates a method for producing cavities 220 between polymer particles 270 in a structure-forming film 200:

• A suspension 280 of polymer particles 270, for example PC particles, is poured onto a circumferential film carrier 500, for example on a metal foil. Subsequently, all the liquid portions 290 of the suspension are evaporated, so that the remaining polymer particles combine with each other and the structure-forming film 200 provided with through cavities 220 between the polymer particles is formed. Subsequently, the structure-forming film can be lifted off the film carrier so that a continuous cavities-containing polymer film is formed. The polymer particles may be partially dissolved in the suspension to enhance adherence of the polymer particles to each other upon evaporation of the liquid components. In addition, the polymer particles may have reactive groups on the surface to effect post-crosslinking so that the layer region has a firm internal cohesion.

List of reference numbers:

100

Substrate, identity card

101

upper substrate surface, upper card surface, upper side

102

lower substrate surface, lower card surface, underside

110

facial image

120

first data field

125

third data field

130

second data field

135

fourth data field

140

internal polymer layers

150

outer protective layer, protective lacquer layer

160

Adhesion area on the substrate

200

(structure-forming) film

210

film element

215

Bottom of the film element, contact side of the film

220

wells

230

Film residue, not the film element corresponding film sections

240

support layer

250

grid cells

260

thin areas

270

polymer

280

Suspension of polymer particles

290

Liquid components

295

separating layer

300

(Punching) tools

310

End face of the punching tool

320

nozzle opening

400

Halftone dot, pixel, three-dimensional structure

400 '

Halftone dot, pixel, three-dimensional structure

500

Foil carrier, metal foil

M

Dissolving or swelling agent

P

Press printing

W

heat generation

Claims (12)

1. Method for forming at least one three-dimensional structure (400,400') on at least one surface (101) of a substrate (100), comprising the following steps:

   a. provision of a substrate (100) and of a structure-forming material in the form of a film (200),

   b. mechanical separation of at least one film element (210) from film part regions (230) which do not correspond to the at least one film element (210), and

   c. non-releasable connection of the at least one film element (210) to the at least one surface (101) of the substrate (100) in each case in one adhesion region (160) of the substrate (100),

   with the result that the at least one film element (210) forms the at least one three-dimensional structure (400, 400') on the at least one surface (101) of the substrate (100),
   characterised in that, in the method step (c), the at least one film element (210), by local application of a solvent or swelling agent (M) for the structure-forming material of the film (200) and/or for the material of the substrate (100), is non-releasably connected in the at least one adhesion region (160) to the at least one surface (101) of the substrate (100).
2. Method according to claim 1, characterised in that the at least one film element (210), with the non-releasable connection with the at least one surface (101) of the substrate (100), comes in direct contact with the at least one surface (101) of the substrate (100).
3. Method according to any one of the preceding claims, characterised in that the at least one film element (210), by local application of pressure in the at least one adhesion region (160) and heating, is non-releasably connected to the at least one surface (101) of the substrate (100).
4. Method according to any one of the preceding claims, characterised in that the structure-forming material of the film (200) comprises cavities (220) which penetrate it, such that solvent or swelling agent (M) applied on a side of the film (200) opposite a contact side (215) of the film (200) with the at least one surface (101) of the substrate (100), will penetrate through the film (200) and can reach the contact side (215) of the film (200).
5. Method according to any one of the preceding claims, characterised in that the structure-forming material of the film (200) is non-releasably connected point by point, in accordance with a matrix, on the at least one surface (101) of the substrate (100).
6. Method according to any one of the preceding claims, characterised in that the film (200) has a thickness from 50 to 150 µm.
7. Method according to any one of the preceding claims, characterised in that the structure-forming material of the film (200) exhibits regularly arranged thin regions (260), such that the at least film element (210) is mechanically separated along thin regions (260) arranged on the film element (210) from film part regions (230) which do not correspond to the at least one film element (210).
8. Method according to any one of the preceding claims, characterised in that the structure-forming material is or at least contains polycarbonate.
9. Method according to any one of the preceding claims, characterised in that the substrate (100) is formed from polycarbonate or at least contains this.
10. Method according to any one of the preceding claims, characterised in that the three-dimensional structures (400, 400') encode an item of information.
11. Method according to any one of the preceding claims, characterised in that the three-dimensional structures (400, 400') form elements of a script for the blind.
12. Method according to any one of the preceding claims, characterised in that the substrate (100) is a value product or security product, or a preliminary product of a value product or a security product.

Images