Process for preparing a product comprising a flexible substrate with at least one patterned layer

Abstract

A patterned multilayer film is prepared from a flexible multilayer film comprising a support layer and at least one conductive layer. In the preparation process, the desired patterns are pre-printed in a raised manner on the support layer of the multilayer film and the conductive layer of the pre-printed multilayer film is subjected to a step of milling to selectively remove predetermined portions of this conductive layer, the predetermined portions having a structure corresponding to the pre-printed raised patterns.

Description

[0001] Title of the invention: Method for preparing a product comprising a flexible substrate with at least one patterned layer

[0002] The present invention relates to a method and device for preparing a product comprising a flexible substrate with at least one patterned layer.

[0003] A known process for manufacturing conductors and electrical components on substrates involves applying a layer of conductive material, illustratively a metal and / or a metal alloy and / or a doped resin, onto a substrate and then removing the undesirable parts of said layer by etching with chemical substances.

[0004] This process has many disadvantages, including the number of steps and the time required to complete it, as well as the use and management of the chemical substances used in the process.

[0005] EP1665912 and WO2022223539 describe similar processes that eliminate the need for chemical substances. In these processes, a printing plate presses the desired pattern onto a conductive top layer placed above a dielectric base layer, and a milling cylinder mechanically removes the raised pattern from the top layer, leaving the base intact. This mechanical removal of material from the conductive top layer, performed simultaneously with the pressing of the desired pattern onto the material, thus allows the desired conductive pattern to remain on the material.

[0006] Although these processes are advertised as particularly effective for creating conductive patterns on materials with a conductive layer, the simultaneous management of patterned dynamometer cylinders and milling equipment creates complexity in the implementation of the process while making some achievements difficult or even impossible.

[0007] Thus, improving a device and a process that facilitate the fabrication of a structure / pattern on a multilayered material, in a simple, fast, and reliable manner, remains a significant challenge to which the present invention advantageously responds, as explained in the remainder of the description of the invention. Description of the invention

[0008] The invention is defined by the independent claims.

[0009] Embodiments are presented in the dependent claims and in the description and figures.

[0010] According to a first aspect, the invention relates to a method for preparing a patterned multilayer film from a flexible multilayer film comprising a support layer and at least one conductive layer, wherein the support layer of the multilayer film is pre-printed in relief according to the desired patterns and the conductive layer of the pre-printed multilayer film is subjected to a milling step to selectively remove predetermined parts of this conductive layer, said predetermined parts having a structure corresponding to the relief preprints.

[0011] Therefore, it is the pre-printed relief that conditions the parts of the conductive layer that are removed during the milling stage.

[0012] In one execution mode, the thicknesses of the predetermined parts are variable.

[0013] This process makes it possible to do away with the patterned cliché cylinders of the earlier art in which the patterned cliché cylinders are presented in the form of a cylindrical support with a patterned envelope surface; with the patterns comprising raised parts which correspond to the parts of material which must be removed and hollow parts which correspond to the parts of material which must be retained.

[0014] Although this process requires two distinct steps, its implementation has proven simple, quick, and reliable, while also offering numerous other advantages. These include improved pattern accuracy and enhanced mechanical strength of the multilayer film, not only during the milling and transport stages but also, optionally, when the embossed designs are retained on the film, during subsequent uses. The process also allows for milling (and therefore pattern creation) near the ends of the multilayer film.

[0015] One advantageous aspect is that the process can be carried out continuously in the corresponding device.

[0016] Flexible multilayer film comprises a backing layer and at least one conductive layer. It can be supplied as a continuous roll or reel of tape or in sheets. Thus, multilayer film can advantageously be supplied from a roll or reel of tape or from a magazine containing a plurality of stacked sheets.

[0017] The support layer is advantageously made of a dielectric material.

[0018] The conductive layer is the layer of the flexible multilayer film that must have a pattern or structure.

[0019] Milling

[0020] The term "milling" refers to any suitable milling technique adapted to selectively remove predetermined portions of at least one conductive layer from a multilayer film. These predetermined portions of the conductive layer of said film thus represent the patterns and can also be of varying thicknesses, depending on whether it is desired to remove part, all, or all of the conductive layer and part of the thickness of the underlying layer (substrate). Milling utilizes a milling cutter that encompasses all rotating bodies having an abrasive surface or a milling envelope equipped with teeth, grains, or abrasive particles, such as sand, diamond particles, or other similar materials.

[0021] The milling cutter can advantageously be in the form of a milling cylinder, for example in the form of a cylindrical milling wheel, with cutting teeth extending along an axial direction of a cylinder envelope surface, for example helically or straight along the axial direction.

[0022] The patterns or structures produced in the multilayer film can vary both in the direction of advancement of the film in the device and in the transverse direction of said device.

[0023] Selective removal of predetermined portions of the conductive layer can be carried out in a single milling step or partially over several consecutive milling steps.

[0024] After the single milling step or the final milling step, at least part of the thickness of the conductive layer, the entire conductive layer, or the entire conductive layer and part of the thickness of the support layer, was cut out by selectively removing predetermined portions, revealing the desired patterns.

[0025] Since the multilayer film may advantageously include layers other than the support layer and the conductive layer, milling may also include the removal of material from other layers, such as one or more cover layers overlying the conductive layer or one or more underlying layers of the conductive layer.

[0026] In one embodiment, a single milling cutter will suffice to perform the single step or the plurality of milling steps.

[0027] As an alternative, a plurality of identical or different strawberries can be provided.

[0028] Since milling can cause temperature increases in the multilayer film, a cooling and / or lubrication station can be advantageous complements to the milling station to prevent damage to the multilayer film. For example, the cooling station might include a cooled cylinder or an air blade. Similarly, the lubrication station could consist of a spray system or a scraper system.

[0029] Support layer

[0030] The support layer is therefore advantageously made of a dielectric material. This support layer can itself be multilayered; it can thus include one or more dielectric films. The support layer, or more generally the dielectric material, can be made of paper or a plastic material, for example, paper, polyethylene terephthalate, polycarbonate, polyimide, and / or polyethylene polynaphthalate.

[0031] This support layer may advantageously have a thickness greater than or equal to 20 microns, for example greater than or equal to 35 microns. This support layer may advantageously have a thickness less than or equal to 200 microns, for example less than or equal to 100 microns.

[0032] In the illustration where the entire conductive layer and a portion of the backing layer have been cut away by selectively removing predetermined sections to reveal the desired patterns, it is obvious to those skilled in the art that the thickness of the backing layer will have been reduced in the areas of said patterns. To ensure the integrity of the film, and for illustrative purposes, at least 75% of the backing layer thickness, for example, at least 90% of said thickness, is retained.

[0033] Conductive layer

[0034] The conductive layer can advantageously be formed of one or more metals, a metallic alloy and / or a conductive polymer. It can consist of aluminium, copper, aluminium coated with copper, tin, gold, silver, nickel, carbon, and / or a corresponding alloy, for example a copper alloy or a copper-nickel alloy.

[0035] This conductive layer can advantageously have, before the milling stage, a thickness greater than or equal to 5 microns, for example greater than or equal to 40 microns.

[0036] This conductive layer can advantageously have, before the milling stage, a thickness less than or equal to 150 microns, for example less than or equal to 100 microns.

[0037] The multilayer film may also include one or more additional layers to the support and conductive layers.

[0038] For example, the conductive layer can be covered with a protective layer.

[0039] This protective layer can advantageously be made of a dielectric material, which will be advantageously selected from the dielectric materials already described for the support layer; this material may be the same as or different from that of the support layer. The presence of a protective layer or any other layer placed above the conductive layer to be milled will necessitate that it also be milled during the pattern creation process. The multilayer film may also include one or more additional conductive layers, the material of which will be advantageously selected from the conductive materials already described above for the conductive layer to be milled; this material may be the same as or different from that of the conductive layer to be milled.

[0040] The additional conductive layer(s) may have substantially the same thickness as the conductive layer to be milled, or a different thickness (lower or higher).

[0041] This additional conductive layer or layers can advantageously be arranged as an intermediate conductive layer sandwiched between the support layer and an additional intermediate dielectric layer. In this arrangement, the conductive layer to be milled is positioned above this intermediate dielectric layer.

[0042] Alternatively, the support layer can be placed between the conductive layer to be milled and the additional conductive layer.

[0043] The embossing stage consists of pre-printing the substrate layer of the multilayer film with the desired embossed pattern. Any suitable printing method can be used, provided it allows the embossed pattern to be created on the opposite side of the multilayer film, the side opposite the one that will be milled.

[0044] PRINTING PRODUCT

[0045] In one embodiment, the printed product can consist of 3D varnish; it can also consist of hot melt inks / glues (hardening at room temperature).

[0046] In one embodiment, the printing product comprises a thermoplastic material, for example a thermoplastic polymer, and optionally, a thermosetting material. This printing product, pre-printed on the opposite side of the multilayer film (relative to the side on which the milling will be performed), guarantees the design of the future milled pattern and therefore of the prepared patterned multilayer film.

[0047] For illustrative purposes only and not as a limitation, this printing product may consist of toner and / or ink and / or varnish; it is preferably dielectric.

[0048] For illustrative purposes only, and not as a limitation, in the case of a varnish, it can be solvent-based, water-based, or UV-cured. When it is UV-cured, it can be cross-linked using LEDs and / or UV radiation.

[0049] In one particular embodiment, the printing product is a UV ink and / or UV varnish comprising a thermosetting material as well as a thermoplastic material; the presence of at least one photoinitiator in the composition of the printing product is also preferred. It is the presence of this thermosetting material that characterizes the fact that the corresponding ink / varnish exhibits thermosetting behavior. In another particular embodiment, the pre-printed printing product (and therefore the pre-printed design) is crosslinked before the milling step. This can result in the polymer network of the printing product being at its optimum in terms of three-dimensional density through the reaction of all the photoinitiator sites.This can also result in thermosetting behavior, meaning that the thermosetting part of the varnish no longer has a glass transition temperature Tg but only a destruction temperature; thus, this thermosetting polymer present in the varnish will never become soft and will not develop a sticky surface because it will be completely dry to the touch.

[0050] Thus, according to certain embodiments, the claimed process includes, after the printing step of the printed product and before milling, an activation step (for example by means of UV rays) allowing the printing product (the ink and / or varnish) to be crosslinked.

[0051] The addition of a thermoplastic material to the printing product has improved the selective adhesion between the printed pattern and the multilayer film.

[0052] In a particular embodiment, the printing product, preferably of the ink / varnish type, comprises at least 5% by weight of thermoplastic material, for example at least 10% by weight, preferably at least 15% by weight. Even if high concentrations of thermoplastic material are conceivable, the printing product, preferably of the ink / varnish type, will preferably comprise less than 40% by weight, for example less than 30% by weight, preferably less than 25% by weight of thermoplastic material.

[0053] Thus, in a particular embodiment, the printing product, preferably of the ink / varnish type, comprises at least 60% by weight, for example at least 70% by weight, preferably at least 75% by weight of material intended to be thermosetting.

[0054] Thus, in an embodiment particularly applicable to varnishes / inks, the thermoplastic material is characterized by a Tg value of less than 60°C, for example less than 50°C, preferably less than 40°C.

[0055] Since the ink / varnish type printing product contains only limited amounts of thermoplastic material, it is evident that the Tg of the printing product after deposition (and crosslinking) will have a value that will be different from the Tg of the thermoplastic material contained in said product.

[0056] When the printing product is a toner, its thermoplastic content is generally greater than 30% by weight, greater than 40% by weight, or even greater than 50% by weight.

[0057] In a particular embodiment, the printing product is an ink or a varnish. After deposition / curing, this printing product is in the form of a film which is advantageously characterized by a Tg value between -20°C and 200°C, for example between 0°C and 200°C, for example between 10 and 50°C, for example between 15°C and 40°C.

[0058] In a particular embodiment, the printing product is a toner. After deposition, for example by xerography, this printed printing product is in the form of a film which is advantageously characterized by a Tg value between 0°C and 200°C, for example between 40°C and 120°C, for example between 40°C and 70°C.

[0059] The temperature (Tg) of the film in the printed / (cured) (varnish / ink / toner) product will be measured using any appropriate method. As an example, we will mention Differential Scanning Calorimetry (DSC), a well-established thermal analysis method for measuring various temperatures and transition states.

[0060] As an illustration, the polymer sample will be subjected to a temperature ramp of approximately 10°C / min, with the heat flux measured in watts. The glass transition temperature (Tg) marks the shift from the glassy to the rubbery state of the material, an endothermic phenomenon. Therefore, to determine the Tg value, one simply waits for a decrease in heat flux as a function of temperature and then uses a tangential method. The resulting value corresponds to the Tg of the polymer using the DSC method.

[0061] The sample used for the measurement may advantageously come from the material constituting the printed product after printing and curing.

[0062] In one embodiment, any UV varnish usable in the field of non-contact printing, and more particularly in the field of digital non-contact printing using piezoelectric printheads, can advantageously be used. Inkjet deposition is well known to those skilled in the art and can be carried out using a known inkjet deposition technique, preferably the drop-on-demand (DOD) technique, which consists of creating overpressure using a piezoelectric component that bends under the effect of an electrical voltage to reduce the volume of the ink reservoir and thus eject a drop of varnish.

[0063] While there are no strict restrictions on the choice of UV varnish suitable for inkjet deposition within the scope of the present invention, it is nevertheless advantageous to select certain characteristics to maximize the final result. Therefore, it is clear that preference will be given to UV varnishes compatible with inkjet nozzles.

[0064] This implies that the choice of non-contact UV varnish, preferably a UV varnish for inkjet nozzles (preferably for piezoelectric printheads), will preferably be based on one or more of the following criteria: - a varnish viscosity of less than 500 mPa.s at 25°C, preferably less than 200 mPa.s at 25°C, preferably less than 100 mPa.s at 25°C, for example less than 50 mPa.s at 25°C; and / or

[0065] - the absence in the varnish of components with a particle size greater than or equal to 50 µm, preferably the absence of components with a particle size greater than or equal to 10 µm, and even more preferably the absence of components with a particle size greater than or equal to 1 µm. Indeed, the varnishes used are preferably systematically filtered to guarantee the safety and reliable operation of the print heads; and / or

[0066] - a surface tension of the varnish between 10 mN / m and 50 mN / m at 25°C, preferably between 18 and 25 mN / m at 25°C in order to ensure efficient spreading on a wide range of substrates.

[0067] Thus, in certain embodiments, the varnish (for coating the surface of a substrate and deposited by inkjet) will have a composition that preferably meets one or more of the criteria indicated below: the presence of at least one monofunctional or difunctional acrylate curable monomer, or a mixture of two or more monofunctional and / or difunctional acrylate curable monomers, preferably in a content greater than 50% by weight, for example in a content between 60 and 85% by weight of the varnish; and / or the absence in the varnish of a urethane-based compound, and / or the absence in the varnish of an acrylate curable monomer of sole acrylate functionality and whose said functionality is greater than 3; and / or the presence of a photoinitiator, preferably in a content between 2 and 10% by weight of the varnish; and / or the presence of a surfactant, preferably in a content of between 0, 1 and 3% by weight of the varnish;and / or the presence of passive (non-reactive) resins, preferably in a content of between 5 and 20% by weight of the varnish; and / or the presence of modified acrylate amine, preferably in a content of between 2 and 10% by weight of the varnish; and / or the varnish composition being preferably solvent-free or preferably free of water and organic solvents such as, for example, methyl isobutyl ketone, methyl ethyl ketone, dimethyl ketone, isopropyl alcohol, isobutyl alcohol, n-butyl alcohol, ethyl acetate, n-butyl acetate, ethyl cellosolve, butyl cellosolve and other similar solvents.

[0068] According to one embodiment, the sum of the varnish components mentioned above will preferably represent at least 70% by weight of the varnish, preferably at least 85% by weight, for example at least 95% by weight, or even the entirety of the varnish.

[0069] According to a preferred, but not limiting, method of operation, the physical parameters of the components or composition of the UV-based varnish are determined at the indicated temperatures and under typical Earth surface pressure conditions, preferably on the order of one atmosphere (1013 m bar). Viscosity can thus be measured using a HAAKE Viscotester 550 viscometer equipped with a Cup NV and Rotor NV, which are well-known measuring instruments marketed by Thermo Fisher Scientific. This instrument incorporates a temperature control system connected to a thermostatically controlled bath, which maintains the varnish sample at a temperature of 25°C. Similarly, surface tension is measured using a DSA 100 tensiometer with the droplet method, marketed by KRÛSS Scientific.Particle size and conductivity are respectively measured using on the one hand a particle size measuring device called MASTERSIZER 2000, marketed by the company MALVERN, and on the other hand a CYBERSCAN CON 1 1 conductivity meter from EUTECH INSTRUMENTS with a reference measuring cell ECCONSEN91 W / 35608-50 whose cell constant is K=1 .0.

[0070] Among the curable monofunctional acrylate monomers that can advantageously be used in varnishes, examples include monoacrylates and / or compounds derived from said monoacrylates, taken individually or in mixtures of two or more of said compounds. For illustrative purposes, aliphatic alkyl monoacrylates and / or their derivatives, in particular aliphatic alkyl monoacrylates with more than five carbon atoms, and / or their derivatives, are examples. Aromatic alkyl monoacrylates and / or their derivatives, in particular aromatic alkyl monoacrylates with more than five carbon atoms, and / or their derivatives, are also examples.Examples include, but are not limited to, 2-(2-ethoxyethoxy) ethyl acrylate "EOEOEA", phenol ethoxylated monoacrylate, Cyclic Trimethylopropane Formal Acrylate "CTFA", F octyl e-decyl acrylate "ODA" (which also has the property of restricting surface tensions in varnish), tridecyl acrylate "TDA", octyl acrylate, isodecyl acrylate "IDA", 3,3,5 trimethyl cyclohexyl acrylate, iso octyl acrylate "IOA", isobornyl acrylate "IBA", 3,3,5 trimethyl cyclohexanol acrylate "TMCHA", tetrahydrofurfuryl acrylate "THFA", and / or a mixture of two or more of the aforementioned compounds.

[0071] Among the difunctional diacrylate curable monomers that can advantageously be used in varnishes, examples include diacrylates and / or compounds derived from said diacrylates, taken individually or in mixtures of two or more of said compounds. For example, aliphatic alkyl diacrylates and / or their derivatives, in particular aliphatic alkyl diacrylates with more than five carbon atoms, and / or their derivatives. Also for example, aromatic alkyl diacrylates and / or their derivatives, in particular aromatic alkyl diacrylates with more than five carbon atoms, and / or their derivatives.Examples include, but are not limited to, triethylene glycol diacrylate (TIEGDA), tripropylene glycol diacrylate (TPGDA), dipropylene glycol diacrylate (DPGDA), polyethylene glycol diacrylate, polypropylene glycol diacrylate, propoxylated neopentylglycol diacrylate, hexanediol diacrylate (HDDA), esterdiol diacrylate (EDDA), 3 Methyl 1,5 pentanediol diacrylate (MPDA), polybutadiene diacrylate (PBDDA), decanediol diacrylate (DDDA), tricyclodecanedimethanol diacrylate (TCDDMDA), tetraethylene glycol diacrylate (TTEGDA), and / or a mixture of two or more of the aforementioned compounds.

[0072] PRINTED PATTERN

[0073] Any suitable method can be used for embossing. Examples include, but are not limited to, screen printing, inkjet printing, xerography, etc. Depending on the specific method, the printed product is digitally printed, for example, by inkjet or xerography, preferably by inkjet printing. This inkjet printing allows for very precise embossing of areas or designs, depending on the composition of the printed product. Toner xerography is another option well known to those skilled in the art.

[0074] This printing step will therefore be advantageously digital, for example by inkjet printing of varnish / ink or by electrophotographic printing (xerography) of toner.

[0075] An advantageous feature of the claimed process and device is that the digitally printed relief pattern consists of a printing product (varnish / ink / toner) which is compatible in terms of surface tension with the support layer of the multilayer film (in particular with its porosity), resulting in a high resolution of the printed pattern which will generate high precision of the pattern when milling the opposite layer.

[0076] When the printing product is an ink or varnish, inkjet printing techniques with raised printing of the design will be preferred, for example using piezoelectric print heads, adapted according to the printing product.

[0077] The areas (and therefore the patterns) can advantageously be any kind of desired geometric shape; they can theoretically be made of different materials, for example inks and / or varnishes and / or toner, although it is preferable to use only one type of dielectric printing product when embossing.

[0078] In one embodiment, thanks to the illustrated printing techniques, the thickness of the printed product can advantageously be variable; this makes it possible to obtain a patterned film whose conductive characteristics are precisely controlled.

[0079] We will cite by way of illustration and not limitation a thickness of the film of printing product (ink / varnish / toner) deposited / dried and measured before milling equal to or greater than the thickness of conductive layer to be milled.

[0080] For illustrative purposes, the thickness of the printing product film is equal to or greater than 4 microns, for example equal to or greater than 5 microns, for example equal to or greater than 15 microns, for example equal to or greater than 40 microns; and / or a thickness of the printing product film (ink / varnish / toner) deposited / dried and measured before milling less than 250 microns, for example less than or equal to 100 microns.

[0081] Optionally, the embossing step is followed by a drying step at the end of which the thickness of the printed and dried printed product is equal to or greater than 4 microns, equal to or greater than 5 microns, equal to or greater than 15 microns, or equal to or greater than 40 microns.

[0082] Optionally, the embossing step is followed by a drying step at the end of which the thickness of the printed and dried print product is equal to or greater than the thickness of the conductive layer to be milled.

[0083] Optionally, the embossing step is followed by a drying step after which the thickness of the printed and dried printed product is less than 250 microns, or less than or equal to 100 microns.

[0084] Optionally, the thicknesses of the predetermined parts are variable.

[0085] Optionally, the printed product is digitally printed using inkjet printing.

[0086] According to a second aspect, the invention relates to a device for preparing a patterned multilayer film from a flexible multilayer film comprising a support layer and at least one conductive layer, the device comprising at least one embossing station in which the support layer of the multilayer film is pre-printed in relief according to the desired patterns and a milling station configured to selectively remove predetermined parts of this conductive layer from the pre-printed multilayer film, said predetermined parts having a structure corresponding to the embossed preprints.

[0087] The device is therefore configured in such a way that, during its use, the embossed pre-printing of the multilayer film generates a corresponding emboss on the opposite side of the film as it passes through the milling station, a corresponding emboss which can be selectively milled to produce the patterned multilayer film.

[0088] The process and device described in the aspects of the present invention can be used to produce the flexible patterned multilayer film.

[0089] Thus, according to a third aspect, the invention relates to a flexible multilayer patterned film prepared by the claimed process.

[0090] Thus, according to a fourth aspect, the invention relates to a flexible multilayer patterned film prepared using the claimed device.

[0091] The flexible patterned multilayer film can advantageously be used as an electronic component and therefore advantageously used in fields where electronic components are useful, for example for heating elements, radiators, LED lighting, cable harnesses, flexible printed circuits, etc.

[0092] Figures

[0093] [Fig. 1] Figure 1 represents an example of an embodiment of the device and the method for preparing a patterned multilayer film related to the invention.

[0094] [Fig.2] Figure 2 represents an example of an embodiment of the milling / cleaning device 7 and the corresponding process in relation to the invention.

[0095] [Fig.3] Figure 3 represents two examples of film production (FILM I and FILM II) related to the invention.

[0096] For illustrative purposes, Figure 1 describes the roll-to-roll device for the multilayer film in strip form and is read from right to left. It depicts a multilayer film unwinder 1, a preferred optional tape guide 2, a preferred optional registration device 3, a printing device 4 (preferably an inkjet system), a drying device 5, a preferred optional control device 6, a milling / cleaning device 7, a preferred optional tape guide 8, a preferred optional control device 9, a patterned multilayer film rewinder 10, and control means 11 for the device. These control means are preferably computer-based; these computer-based means advantageously control the various workstations and also collect information from the various sensors installed along the device in order to synchronize the successive steps.The registration device 3 may advantageously include a camera, sensor, and / or scanner to synchronize operations and, in particular, to position the embossed print using a computer file representing the design based on registration marks located on the film. The inkjet printing system 4 may include a print bar or a set of print heads operating in scanning mode. In scanning mode, the machine may include magazines (consisting of rollers that can move apart and together) to store a portion of the web (called "buffers") to allow continuous operation of the milling system. Preferably, the ink / varnish used is colored to facilitate optical verification of print quality with the control device 6.

[0097] The control device 9 allows for verification of the quality of the processed film production. It advantageously includes an optical control and / or a thickness control device.

[0098] The aforementioned computer means do not need to be detailed in this application and may, for example, be integrated into the device or housed in a separate device. The sensors provide, for example, information on film position, film configuration information, and information on areas to be printed and / or milled, and / or validation information following a correctly performed or incorrect operation. Certain information necessary for the implementation of the invention may also be pre-recorded in the computer means (for example, via input on an interface by an operator). Such information may, for example, concern the shape and / or dimensions of the films (e.g., their thickness), the location of the patterns to be printed and / or milled, the thickness of the ink and / or varnish layer, the drying power, etc., but it is generally preferred that sensors measure or verify such information.

[0099] In the illustration shown in Figure 1, the films are therefore unwound / rewound in a roll-to-roll device. Alternatively, the films awaiting printing can be in sheet form and are generally, in a manner known per se, placed in at least one input area, for example, an input magazine with a storage capacity defined according to the nature of the substrate and the printing requirements. In one embodiment, an input magazine is designed to accept several dozen, hundreds, or even thousands of substrates of varying nature, thickness, and dimensions (for example, but not limited to, formats with sides on the order of a centimeter, such as A10, or more precisely, credit card size; up to formats with sides on the order of several meters, such as AO or 2 x 2 meters).Once the printing process is complete, the substrates are directed to an output area, for example, stored in at least one output magazine, which typically has the same storage capacity as the input magazine. A suitable substrate transport system through the printing / milling stations is also included in this illustration.

[0100] By way of illustration, Figure 2 describes an example of an embodiment of the milling / cleaning device 7 and the corresponding method related to the invention. This device 7 advantageously comprises an input tension adjustment device 71 for the film to be milled, an output tension adjustment device 72 for the milled / cleaned film, a milling device 73, an optional and preferred cleaning device 74, an optional and preferred suction device 76, and a counter-pressure roller 75.

[0101] The milling / cleaning device 7 may advantageously include one or more milling rollers adjustable in speed and distance from the counter-pressure roller(s) 75. Several milling rollers allow for progressive milling which limits the risk of tear-out.

[0102] The milling / cleaning device 7 may advantageously include one or more cleaning systems composed, for example, of suction brushes or electrostatic systems.

[0103] The inlet tension adjustment device 71 for the milling film and the outlet tension adjustment device 72 for the milled / cleaned film are advantageously motorized. They assist in the movement of the film and allow its tension to be adjusted.

[0104] Figure 3 shows two examples of film production, FILM I on the left and FILM II on the right. The upper part of the figure shows the conductive layer of the film, which is thicker in FILM II. The lower part shows the raised varnish / ink patterns; the relief is of the same thickness in printed FILM I and of varying thickness in printed FILM II. In the middle is the film support layer.

[0105] In the lower part of the figure we can see the milled film with the conductive layer of the film in the upper part, selected parts of which (corresponding to the patterns of the relief prints) are milled, entirely in FILM I and sometimes partially in FILM II (depending on the variable thickness of the printed relief), and in the middle, the support layer of the film.

[0106] This application describes various technical features and advantages with reference to the Figures and / or various embodiments. Those skilled in the art will understand that the technical features of a given embodiment can in fact be combined with features of another embodiment unless the contrary is explicitly stated, or it is obvious that such features are incompatible, or that the combination does not provide a solution to at least one of the technical problems mentioned in this application. Furthermore, the technical features described in a given embodiment can be isolated from the other features of that embodiment unless the contrary is explicitly stated.

[0107] It should be obvious to those skilled in the art that the present invention allows for embodiments in many other specific forms without departing from the scope of the invention as claimed. Therefore, the present embodiments should be considered illustrative, but may be modified within the scope defined by the attached claims, and the invention should not be limited to the details given above.

Claims

Demands 1. A method for preparing a patterned multilayer film from a flexible multilayer film comprising a support layer and at least one conductive layer, characterized in that a pre-printed relief pattern is carried out on the support layer of the flexible multilayer film comprising the support layer and at least one conductive layer, and the conductive layer of the pre-printed multilayer film is subjected to a milling step to selectively remove predetermined parts of this conductive layer, said predetermined parts having a structure corresponding to the pre-printed relief patterns.

2. Method for preparing a multilayer film according to claim 1 in which the support layer is made of a dielectric material.

3. Method of preparing a multilayer film according to claim 2 in which the dielectric material is formed of paper or a plastic material, for example paper, polyethylene terephthalate, polycarbonate, polyimide and / or polyethylene polynaphthalate.

4. Method for preparing a multilayer film according to any one of the preceding claims wherein the support layer has a thickness greater than or equal to 20 microns, or even greater than or equal to 35 microns.

5. Method for preparing a multilayer film according to any one of the preceding claims wherein the support layer has a thickness less than or equal to 200 microns, or less than or equal to 100 microns.

6. Method for preparing a multilayer film according to any one of the preceding claims wherein the conductive layer is formed of one or more metals, a metallic alloy and / or a conductive polymer.

7. Method for preparing a multilayer film according to claim 6 wherein the conductive layer is made of aluminium, copper, aluminium coated with copper, tin, gold, silver, nickel, carbon, a corresponding alloy, a copper alloy, and / or a copper-nickel alloy.

8. Method for preparing a multilayer film according to any one of the preceding claims wherein, before the milling step, the conductive layer has a thickness greater than or equal to 5 microns, or greater than or equal to 40 microns.

9. Method for preparing a multilayer film according to any one of the preceding claims wherein, before the milling step, the conductive layer has a thickness less than or equal to 150 microns, or even less than or equal to 100 microns.

10. Method for preparing a multilayer film according to any one of the preceding claims wherein the milling step is carried out by means of a milling cutter (7) in the form of a milling cylinder, for example in the form of a cylindrical milling wheel, with cutting teeth extending along an axial direction of an envelope surface of the cylinder, for example helically or straight along the axial direction.

11. Method for preparing a multilayer film according to any one of the preceding claims wherein the embossing step is carried out using a printing product which is a 3D varnish.

12. Method for preparing a multilayer film according to any one of the preceding claims wherein the embossing step is followed by a drying step at the end of which the thickness of the printed and dried printed product is equal to or greater than 4 microns, equal to or greater than 5 microns, equal to or greater than 15 microns, or equal to or greater than 40 microns.

13. Method for preparing a multilayer film according to any one of the preceding claims wherein the embossing step is followed by a drying step at the end of which the thickness of the printed and dried printing product is equal to or greater than the thickness of the conductive layer to be milled.

14. Method for preparing a multilayer film according to any one of the preceding claims wherein the embossing step is followed by a drying step at the end of which the thickness of the printed and dried printed product is less than 250 microns, or less than or equal to 100 microns.

15. Method for preparing a multilayer film according to any one of the preceding claims wherein the thicknesses of the predetermined parts are variable.

16. Method for preparing a multilayer film according to any one of the preceding claims wherein the printed product is digitally printed by inkjet printing.

17. A method for preparing a multilayer film according to any one of the preceding claims, wherein the milling step includes a cooling step using a cooling station.

18. A method for preparing a multilayer film according to any one of the preceding claims, wherein the milling step includes a lubrication step using a lubrication station.

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