Functionalised material comprising an encapsulated electronic circuit under leather, method for manufacturing same and article comprising such a material

Abstract

The invention relates to a functionalised material characterised in that it comprises a first leather layer, a second layer, and at least one foil comprising a conductive metal, the at least one foil being cut or etched to form at least one electronic component or to form at least one conductive track electrically connecting at least one electronic component, wherein the foil is inserted between the first leather layer and the second layer, and wherein the first and second layers are bonded together so as to encapsulate the at least one foil comprising a conductive metal. The invention further relates to a method for manufacturing such a functionalised material. The invention further relates to a leather article comprising such a functionalised material.

Description

DESCRIPTION Title of the invention: FUNCTIONALIZED MATERIAL COMPRISING AN ELECTRONIC CIRCUIT ENCAPSULATED UNDER LEATHER, ITS MANUFACTURE METHOD AND ARTICLE COMPRISING SUCH A MATERIAL TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to the field of functionalized materials, that is to say materials which integrate conductive tracks and / or electronic components, such as antennas, switches, touch interfaces, etc.

[0002] The present invention relates more particularly to a functionalized material comprising electrical tracks encapsulated between a first layer of a first material, which is leather, and a second layer of a second material.

[0003] The present invention also relates to a method of manufacturing such a functionalized material and an article or device comprising such a functionalized material, for example a leather goods item or the leather covering of equipment present in the passenger compartment of a car. STATE OF THE ART

[0004] Prior art includes articles and equipment featuring electronic components covered with a layer of leather, such as antennas, switches and other human-machine interface elements, indicator lights, and display elements, among others. The purpose of covering this electronic material with leather is to functionalize the leather, which is valued for its appearance and pleasant feel. This functionalized leather can then be used to integrate into dashboards or steering wheels of automobiles, or into clothing items, for example.

[0005] Integrating electronic components into a leather item or piece of equipment requires conductive traces that serve as electrical connections to the electronic elements. These conductive traces are usually applied to a thin layer of polymer, supplied as a flexible plastic sheet, which also serves as a substrate for the electronic components. This polymer layer, which carries the printed circuit board, is then bonded to a layer of leather, or sandwiched between two layers of leather to form the functionalized leather. In this configuration, stresses applied to the functionalized leather, such as when it is folded or twisted, are transmitted to the traces. Conductive tracks are easily damaged when the leather is deformed. To prevent damage to these conductive tracks, it is known to position them in a part of the leather that will not be subjected to torsion or bending, for example, on a rigid dashboard. It is also known to use a flexible plastic sheet that is at least partially resistant to deformation. For example, flexible plastic sheets are made of polyethylene terephthalate (PET) or polyimides (PI).

[0006] Integrating a layer of plastic polymer into a functional leather item can result in a less pleasant feel. The polymer layer can also cause a noticeable thickening or alter the leather's mechanical behavior. If the leather becomes stiffer, it can make the inside-out stitching process—folding the leather to sew a bag from the inside—more difficult. If the leather becomes thicker, it can make it difficult to pass through a calender. Furthermore, the reduced resistance of polymers to the stresses and torsions inherent in the leather's flexible structure leads to premature degradation of the polymer pathways. Finally, integrating a polymer layer into the leather can make recycling the leather item more difficult and / or increase its carbon footprint. OBJECTS OF THE INVENTION

[0007] The present invention aims to provide a functionalized leather material that remains functional after multiple deformations related to its use. In certain embodiments, the present invention also aims to provide a functionalized leather material that does not include a solid plastic polymer layer as a support for the conductive metal tracks it incorporates.

[0008] To this end, according to a first objective, the invention relates to a functionalized material which comprises: - a first layer made of a primary material which is leather, - a second layer made of a different material, - at least one intermediate zone comprising a metallic track, which has been cut or engraved in a sheet comprising a conductive metal, and possibly at least one electronic component electrically connected to said metallic track, in which said intermediate zone is intercalated between said first layer and said second layer and in which said first and second layers are fixed together so as to encapsulate said metallic track and, if present, said electronic component.

[0009] The term "leather" refers to the material obtained from an animal hide through a tanning process. The leather obtained after tanning has two sides: one side corresponds to the side of the hide where the hair was embedded, i.e., the top of the hide, and the other side corresponds to the side of the hide that was on the flesh side of the animal.

[0010] In the context of this application, the term "functionalized" is used to designate a material comprising at least one electrically conductive metallic track, enabling that material to assume all or part of the function of an electronic device.

[0011] During the fabrication of said functionalized material, at least one metallic trace, previously cut from a metal sheet, is deposited by a transfer technique onto said first or second layer. Typically, said metal sheet is cut or etched to form one or more metallic traces. In some embodiments, the metallic trace itself forms an electronic component, such as an antenna.

[0012] Advantageously, the cutting of the metal sheet is carried out by laser engraving or by a chemical etching process.

[0013] For the purposes of this application, the term "sheet containing a conductive metal" is used to designate a sheet having a layer of electrically conductive metal or made of conductive metal, optionally supplied on a removable flexible substrate. The thickness of the sheet containing a conductive metal is preferably less than 200 micrometers, preferably less than 100 micrometers, and most preferably 50 micrometers or less. For example, the sheet containing a conductive metal is supplied in roll form having a 35-micrometer copper layer coated with a non-conductive acrylic adhesive, supplied on a removable silicone backing.

[0014] It is noted at this stage that the terms "conductive track", "metallic track" and "conductive metallic track" may be used interchangeably in this application.

[0015] According to a process that will be described later in this application, at least one metal track is interposed between the first leather layer and the second layer, and these two layers are bonded together so as to sandwich the metal track. For example, an adhesive is applied to one face of the first leather layer and / or to one face of the second layer before pressing the first and second leather layers together. Alternatively, the first and second leather layers are bonded together by calendering, embossing, stitching, or any other fastening method.

[0016] The inventors found that this arrangement offered good durability for the conductive tracks. Furthermore, the implementation of laser or chemical etching methods provides high repeatability in manufacturing at a reduced cost.

[0017] In some embodiments, the metal tracks integrated into the functionalized material are devoid of any plastic backing sheet. A "backing sheet" is defined as a solid sheet mechanically bonded to the metal tracks. In contrast, the metal tracks of the functionalized leather of the invention are held in place by the first and second layers pressed together and optionally by an adhesive or a dynamic contact layer applied between these two layers.

[0018] The inventors observed that the absence of a plastic backing sheet contributes to the durability of the conductive metal tracks. Indeed, when a plastic backing sheet is present, it acts as a force relay, transmitting the deformations undergone by the functionalized material to said conductive tracks. The provisions of the invention make it possible to eliminate the need for this plastic backing sheet and thus to attenuate the tensile and tensile forces experienced by the conductive tracks. The electrical resistance of these conductive tracks does not increase beyond an acceptable threshold when the functionalized material is subjected to repeated mechanical deformations.

[0019] These provisions are particularly advantageous when the functionalized material is intended to be incorporated into an object whose use implies that it will be subjected to repeated mechanical stresses. Examples include a leather bag incorporating the functionalized material, or a shoe or bracelet.

[0020] According to the invention, an intermediate zone is interposed between said first layer and said second layer. The intermediate zone comprises an electronic circuit formed by at least one metallic track, which has been cut or etched into a sheet comprising a conductive metal.

[0021] In some embodiments, the intermediate zone further comprises a dynamic contact layer allowing movement along the axis of the metallic track relative to the first layer and / or relative to the second layer.

[0022] The dynamic contact layer is preferably formed by depositing or applying a film of liquid or paste product in contact with the metallic track and forming an interface between the metallic track and at least one of the layers among the first layer and the second layer.

[0023] Advantageously, the dynamic contact layer allows the metallic track to slide within the plane of the intermediate zone, this plane being parallel to that of the first and second layers. These arrangements help to reduce the mechanical stresses applied by the first and / or second layers on the metallic track during deformation of the functionalized material.

[0024] In some embodiments, the dynamic contact layer is formed from a contact product selected from a pressure-sensitive adhesive, a latex, and an elastomer.

[0025] In some embodiments, the dynamic contact layer has a Young's modulus between 1 megapascal [MPa] and 1000 MPa, preferably between 1 MPa and 100 MPa.

[0026] In some embodiments, the foil containing a conductive metal comprises a conductive metal selected from copper, aluminum, gold, or silver. In other embodiments, the foil comprises an alloy containing a conductive metal selected from copper, aluminum, gold, or silver. For example, the alloy constituting the foil may be brass. Preferably, the foil is made of a conductive metal or an alloy containing a conductive metal, for example, selected from those mentioned above.

[0027] Advantageously, the metal sheet is formed from a metal or from a metal alloy that exhibits good corrosion resistance, notably copper, brass, or aluminum.

[0028] In some embodiments, said second layer is formed from a second material which is also leather.

[0029] The inventors discovered that the nature of the second layer influences the durability of the conductive tracks. In particular, encapsulating the conductive tracks between two layers of leather yielded satisfactory results in preserving the conductive tracks and / or the components formed by the conductive tracks.

[0030] The rigidity of the material forming the second layer appears important for preserving the conductive tracks. The inventors discovered that a similar rigidity between the first and second layers provides better protection for the conductive tracks. Young's modulus, also called the tensile modulus or longitudinal modulus of elasticity, is used to characterize this rigidity.

[0031] Thus, preferably, the Young's modulus of the second layer is equal to within 0.5 gigapascals (GPa) of the Young's modulus of the first leather layer. In other embodiments, the Young's modulus of the second layer is equal to within 0.4 GPa, 0.3 GPa, or 0.2 GPa of the Young's modulus of the first leather layer. In other words, the difference between the Young's modulus of the first leather layer and the Young's modulus of the second layer does not exceed 0.5 GPa, preferably 0.4 GPa, preferably 0.3 GPa, or preferably 0.2 GPa.

[0032] In embodiments said second layer is a layer which has a Young's modulus between 0.1 GPa and 0.8 GPa, preferably between 0.2 GPa and 0.6 GPa, preferably between 0.25 GPa and 0.55 GPa.

[0033] Advantageously, the first leather layer and the second layer both have a Young's modulus between 0.1 GPa and 0.8 GPa, preferably between 0.2 GPa and 0.6 GPa, preferably between 0.25 GPa and 0.55 GPa. In a particularly advantageous embodiment, the functionalized material comprises a dynamic contact layer as defined above, which has a Young's modulus between 1 MPa and 1000 MPa, preferably between 1 MPa and 100 MPa.

[0034] In some embodiments, said second layer is a layer formed from a material selected from: artificial leather, non-woven textile, natural or synthetic felt, reconstituted leather or oilcloth.

[0035] In some embodiments, the second layer is made of artificial leather, for example, artificial leather made of synthetic fibers bonded together with a resin. For example, the artificial leather is Alcantara [registered trademark], which comprises layers of polyester synthetic fibers bonded together by the hot application of a polyurethane resin.

[0036] In some embodiments, the second layer is a material belonging to the category of non-woven textiles, that is to say an assembly obtained by assembling natural or artificial textile fibers, without weaving or knitting.

[0037] In some embodiments, the second layer is a natural or synthetic felt. Natural felt is a non-woven textile made by pressing and boiling fibers, possibly combined with a chemical treatment. By extension, the term synthetic felt refers to certain non-woven fabrics containing synthetic fibers.

[0038] In some embodiments, the second layer is reconstituted leather. Reconstituted leather can be made from ground leather fibers that are then glued together and / or glued onto a mesh or paper fiber.

[0039] In other embodiments, the second layer is a waxed canvas.

[0040] Preferably, the functionalized material comprises metallic tracks formed in a sheet of conductive metal positioned between a first layer of soft leather and a second layer that is also flexible. The conductive tracks of the functionalized material are also flexible, meaning they can be deformed and then approximately return to their original structure and retain their functionality.

[0041] Thus, "flexible" describes a functionalized material, layer, conductive track, or electronic circuit that is not rigid, brittle, or stiff, but rather bends, stretches, changes shape, or is subjected to external forces without breaking or losing its functionality. A flexible circuit or electronic component, or a flexible conductive track, is one that does not break and retains its conductivity when bent, stretched, twisted, or otherwise deformed. For example, a flexible electronic circuit or conductive track can maintain its conductivity even when deformed under a longitudinal strain of between 10% and 40%, between 10% and 30%, or between 10% and 20%.

[0042] The present invention incidentally aims to integrate electronic components into the material while maintaining a pleasant feel. To achieve this, the applicant company determined that it was important for the user not to perceive any raised areas revealing the presence of the components beneath the leather when using the functionalized material.

[0043] Thus, in embodiments, at least one layer among the first leather layer and the second layer has at least one cavity configured to house at least part of an electronic component.

[0044] Thanks to these arrangements, the thickness of the functionalized material remains virtually constant, making it possible to avoid the presence of unpleasant textures.

[0045] In some embodiments, the intermediate zone comprises a metallic track, cut or engraved in a sheet comprising a conductive metal deposited on a polyurethane support layer.

[0046] Preferably, the polyurethane support layer is a polyurethane film less than 200 pm [micrometers] thick, preferably less than 100 pm, for example between 30 pm and 70 pm.

[0047] The inventors discovered that a polyurethane layer supporting the metal track, when deformed, generated significantly less stress on the metal track than the stresses generated by a support layer made of plastic polymers such as polyethylene terephthalate (PET) and polyimides (PI). Using a polyurethane support layer protects the metal track without generating excessive stress on the circuit through its own deformation.

[0048] In addition, the polyurethane layer supporting the metal track ensures easier handling of this track during the manufacturing operation of the functionalized material.

[0049] In some embodiments, the intermediate zone comprises a metallic track, cut or engraved in a sheet comprising a conductive metal, hot-pressed between two layers of polyurethane support.

[0050] Preferably, each of the polyurethane backing layers is a polyurethane film less than 200 µm thick, preferably less than 100 µm, for example, between 30 µm and 70 µm. For example, the two polyurethane backing layers each have a thickness of 50 µm. This thickness may vary during hot pressing of the layers together.

[0051] For example, the metal track is placed between two polyurethane films in a heat press for 20 seconds at 120°C.

[0052] In addition to the advantages already mentioned above for using a polyurethane backing layer, hot pressing between two polyurethane backing layers provides better protection for the metal track, which is protected on both sides. These measures also ensure even easier handling during the manufacturing of the functionalized material, as hot pressing secures the metal track between the two polyurethane layers.

[0053] In some embodiments, said first layer and second layer are fixed together on at least part of the perimeter of the intermediate zone and said metal track and, if present, said electronic component are not glued to said first and second layers.

[0054] In other words, the first and second layers are bonded together, for example by gluing, leaving a portion of the area between the first and second layers free of glue. The metal trace and any electronic component are placed in this area and are not glued to the first and second layers.

[0055] Thanks to these arrangements, the metal track and any electronic component are not fixed to these layers, allowing the metal track to slide within the plane of the intermediate zone. These arrangements reduce the mechanical stresses applied by the first and / or second layers to the metal track during deformation of the functionalized material.

[0056] In other words, the metal track and any electronic component are free between the first leather layer and the second layer.

[0057] Preferably, the said first layer and second layer are fixed together by means of an adhesive.

[0058] In some embodiments, said first layer and second layer are fixed together on at least part of the perimeter of the intermediate zone and said metal track, the polyurethane support layer(s) and, if present, said electronic component are not glued to said first and second layers.

[0059] This embodiment differs from the one previously described in that the metal track is deposited on a polyurethane support layer or hot-pressed between two polyurethane support layers. This embodiment is similar to the one previously described in that the metal track, any electronic component, and the polyurethane layer(s) are not bonded to the first and second layers. These arrangements allow the polyurethane layer(s) to slide within the plane of the intermediate zone and to reduce the mechanical stresses applied by the first and / or second layer to the metal track during deformation of the functionalized material.

[0060] In some embodiments, the functionalized material comprises at least one light-emitting diode (LED) electrically connected to a conductive track formed in the foil containing a conductive metal, and the functionalized material comprises at least one through-hole positioned to allow light emitted by at least one LED to be seen. Preferably, a translucent element is positioned in said through-hole.

[0061] These features allow for the integration of light sources visible to the user into the functionalized leather.

[0062] According to a second aspect, the invention relates to a method for manufacturing a functionalized material, which comprises: - a step of supplying at least one sheet containing a conductive metal - a cutting or engraving step of said sheet to form at least one conductive track or at least one electronic component - a step involving the supply of a first layer of leather and the supply of a second layer, - a step of positioning said cut or engraved sheet on said first layer of leather or said second layer and - a step of fixing said first layer of leather onto said second layer, so as to encapsulate at least one sheet comprising a conductive metal.

[0063] The goals, advantages and particular characteristics of the manufacturing process of a functionalized material that is the subject of the present invention being similar to those of the functionalized material that is the subject of the present invention, they are not recalled here.

[0064] In embodiments, the step of cutting or engraving said sheet to form at least one conductive track or at least one electronic component includes a step of cutting the sheet comprising a conductive metal by laser engraving.

[0065] In some embodiments, the step of cutting or engraving said sheet to form at least one conductive track or at least one electronic component includes a chemical etching step.

[0066] In some embodiments, the sheet containing a conductive metal is supplied on a first adhesive support.

[0067] In some embodiments, the manufacturing process includes a hot-pressing step of the metal track, cut or engraved in a sheet containing a conductive metal, between two layers of polyurethane support.

[0068] In embodiments, the positioning step of said cut or engraved sheet on said first leather layer or on said second layer includes a transfer of the sheet containing a conductive metal from the first adhesive support to said first leather layer or to said second layer by means of a second adhesive support, called "transfer support".

[0069] According to a third aspect, the invention relates to a leather article comprising a functionalized material which is the subject of the invention, or obtained by implementing the manufacturing process of a functionalized material which is the subject of the invention.

[0070] As an example, the article is a leather goods item which includes a functionalized leather with an antenna and forming part of the leather or lining of the leather goods item.

[0071] As an example, the item is an interior decoration element of a vehicle which includes functionalized leather forming a covering for an armrest or steering wheel, for example.

[0072] As an example, a conductive track formed in the sheet containing a conductive metal forms or electrically connects at least one electronic component chosen from an antenna, a switch, a touch surface or other human-machine interface element, an indicator light or a display element.

[0073] Advantageously, the electronic component formed by the conductive tracks is an antenna enabling short-range wireless communication, for example of the NFC type (short for "near-field communication," also called close-field communication, abbreviated NFC). Such an antenna makes it possible, for example, to communicate information relating to the origin of a leather good, to ensure its authenticity, or to record the identity of its owner.

[0074] The advantages, purposes and characteristics of a leather article being similar to those of the manufacturing process of a material which is the subject of the invention or to those of the material which is the subject of the invention, they are not recalled here. BRIEF DESCRIPTION OF THE FIGURES

[0075] Other advantages, purposes and particular features of the invention will become apparent from the following non-limiting description of at least one particular embodiment of the functionalized material and process that are the subject of the present invention, with reference to the accompanying drawings, in which:

[0076] [Fig 1] represents, in cross-section, layers of leather that can be used in particular embodiments of the functionalized material that is the subject of the invention. [Fig 2] represents, schematically, in perspective and in partial section, a first particular embodiment of a functionalized material which is the subject of the invention. [Fig 3] schematically represents a cavity-cutting step during the manufacture of a functionalized material according to a second particular embodiment of the invention. [Fig 4] schematically represents the first leather layer of the second embodiment of the functionalized material, during its manufacture. [Fig 5] schematically represents the step of fixing the functionalized material according to the second embodiment of the invention. [Fig 6] represents, schematically and in cross-sectional view, the material functionalized according to the second embodiment of the invention. [Fig 7] represents, schematically and in cross-sectional view, a third particular embodiment of a functionalized material that is the subject of the invention. [Fig 8] represents, schematically and in cross-sectional view, a fourth particular embodiment of a functionalized material that is the subject of the invention. [Fig 9] represents, in the form of a logic diagram, a first particular embodiment of a manufacturing process for a functionalized material that is the subject of the invention. [Fig 10] represents, in the form of step-by-step diagrams, the first particular embodiment of the manufacturing process of a functionalized material that is the subject of the invention. [Fig 11] schematically represents, in cross-section, a fourth particular embodiment of a functionalized material that is the subject of the invention.

[0077] The reference numbers mentioned in the figures refer to: 20, 30, 40, 50, 60 functionalized material 212, 312, 412, 512 second face of the pre¬ 601 intermediate zone, first layer of leather, 210, 310, 410, 510, 610 first layer in 216, 416, 516 first face of the first leather layer in leather 220, 320, 420, 520, 620 second layer 910 grain leather 221, 321, 421 first face of the second 911 full grain layer 912 outer surface of the leather grain 222, 322 second face of the second 915 corrected grain layer 916 internal surface of the leather grain 240, 340, 440, 540, 640 conductive track 920 leather split 250, 351, 352, 353 electronic component 921 outer surface of the leather grain 550, 650 Transponder 922 inner surface, or flesh side, of the 551 Leather-crusted bridge 454, 455, 456 light-emitting diode 930 engraving diagram 260, 561, 663, 562 cavity 955 adhesive support of the sheet includes 671, 672 Polyurethane films are both a conductive metal 801, 802 Laser beam 960 sheet containing a conductive metal DETAILED DESCRIPTION OF THE INVENTION

[0078] The present description is given by way of non-limiting attribution, each feature of an embodiment being able to be advantageously combined with any other feature of any other embodiment.

[0079] Figure 1 shows a side view of layers 910 and 920 resulting from the splitting of a cowhide.

[0080] Layer 910 is the grain of the leather; this is the part located on the side where the hair was embedded, obtained after splitting the hide. It is shown here in cross-section, revealing surface 912, which corresponds to the outermost layer of the epidermis. Surface 912 is preferably left exposed on a leather item, as it offers the most pleasant feel and can reveal the natural texture of the leather. Within the grain of the leather, two thicknesses can be distinguished. On the one hand, full grain 911, which corresponds to a grain of leather that has not been reduced in size or whose layer closest to the epidermis has been retained. On the other hand, corrected grain 915, which corresponds to a grain of leather whose layer closest to the epidermis has been sanded to remove imperfections. The 910 grain leather has a second side 916, which can be called the "corrected grain side" or "flesh side".

[0081] Layer 920 is the split leather, the part in contact with the animal's flesh, obtained after the hide has been split. The split leather has an outer surface 921 that was in contact with the grain of the leather before it was split, and an inner surface 922, previously attached to the animal's flesh.

[0082] Figure 2 shows a functionalized material 50, the object of the invention, represented in perspective view, in partial section. The functionalized material 50 It comprises a first layer 510 of leather, preferably a grain leather layer, for example, a goatskin grain leather of the type illustrated in Figure 1. The first layer 510 has a first face 516 and a second face 512. The second face 512 is intended to be visible to the user; preferably, it is the outermost layer of the epidermis, which may have characteristic leather textures. The first face 516 is the face opposite the second face 512.

[0083] The functionalized material comprises a conductive metal sheet. The conductive metal sheet was cut by laser engraving or chemical etching and then deposited onto the first leather layer 510 using a process that will be better understood from the description in Figures 9 and 10. The conductive metal sheet was cut in a spiral pattern to form a conductive track 540, which serves as an antenna for a transponder 550 configured for wireless communication using NFC (Near Field Communication). An electrical connection is made between the transponder 550 and the inner end of the spiral formed by the conductive track 540. This connection can be made using conductive ink, conductive adhesive, solder, or any other suitable electrical conductor.In addition, a second electrical connection is made between the transponder 550 and the outer end of the spiral formed by the conductive track 540. This second connection can be made by means of an electrical bridge 551, which overlaps the conductive track 540.

[0084] The functionalized material comprises a second layer 520. Preferably, the second layer 520 is made of leather, for example, full-grain or split leather. Alternatively, the second layer is made of another material. Preferably, this material has a rigidity close to that of leather. In some embodiments, the second layer is made of artificial leather, Alcantara artificial leather (registered trademark), natural felt, synthetic felt, reconstituted leather, or oilcloth. Preferably, the first and second layers do not contain any plastic polymers.

[0085] Note that, as illustrated in Figure 2, the sheet containing a conductive metal has been cut to form a circuit configured to function as an antenna. In other embodiments, the sheet containing a conductive metal can be cut to form any other arrangement of conductive tracks to perform other electronic circuit functions. Examples include a switch, a touch surface, another human-machine interface element, an indicator light, a display element such as an LED matrix, or a combination thereof. If necessary, any electronic component can be added to the functionalized material.

[0086] In some embodiments, the first leather layer 510 and the second layer 520 are joined together by means of an adhesive (not shown) and by contact. In all cases, when the first leather layer 510 and the second layer 520 are joined together, at least a portion of the first face of the second layer 520 is fixed to the first face 516 of the first leather layer 510.

[0087] The area between the first leather layer 510 and the second layer 520 is called the "intermediate zone." The conductive track 540 is located in this intermediate zone. Advantageously, the intermediate zone includes a dynamic contact layer formed by depositing or applying a film of liquid or paste-like material in contact with the conductive track 540 on one side, and in contact with the first layer 510 and the second layer 520 on the other. The conductive track 540 is thus "floating" within the dynamic contact layer.

[0088] Advantageously, a product that allows both the first layer of leather 510 and the second layer 520 to be fixed together and also serves as a product forming the dynamic contact layer will be implemented.

[0089] In one particular embodiment, the adhesive used for this dual purpose is a pressure-sensitive adhesive.

[0090] After the first leather layer is joined to the second layer, the conductive tracks are encapsulated, meaning they are completely covered. This process preserves the conductive tracks, as demonstrated by durability tests conducted by the inventors. Durability tests

[0091] A durability test was carried out on functionalized materials, the subject of the invention, on different substrates [layer assembly].

[0092] For each test, a test specimen was created. The specimen is formed from an assembly of the leather to be tested and consists of a thin central section and two larger end sections. During the test, the two end sections of the specimen are held by a support to maintain the specimen horizontally. A mechanical arm then brings a cylindrical solid with a radius of 5 mm into contact with the specimen. The lateral face of this solid applies a downward force at a right angle to the central section of the specimen, deforming it. At each cycle, a force is applied, and then the solid is lifted, allowing the specimen to return to its original shape. A force causing a vertical displacement of 2.9 millimeters is applied to the specimens. One thousand cycles of deformation and release are performed during the test.

[0093] Prior to the test, the initial electrical resistance Ro for each test specimen is measured. Throughout the test, the electrical resistance of the conductive track is measured. The ratio of the measured resistance during the test to the initial resistance Ro is called R / Ro. The maximum R / Ro value recorded during the test indicates the degradation of the conductive tracks: the higher this value, the more degraded the tracks.

[0094] In the first series of tests, two test specimens are prepared. The specimens are prepared by placing a track formed by laser cutting a sheet of metal between two layers of leather, using a process similar to that shown in Figures 9 and 10. These leather layers are then bonded together to encapsulate the conductive tracks. The first specimen has a conductive track formed by laser cutting a sheet of conductive metal encapsulated between two layers of bovine leather. The second specimen has a conductive track formed by laser cutting a sheet of conductive metal encapsulated between two layers of goatskin leather.

[0095] The results of the durability test are presented in Table 1 below. Note that the R / Ro Max ratio measured for each of the two tests presented in Table 1 is 1.022 and 1.027, respectively. These values ​​indicate that the resistivity of the conductive tracks varied very little during the test and that these tracks remain functional after the durability test.

[0096] [Table] Detailed description of certain manufacturing steps

[0097] Figures 3, 4, and 5 illustrate certain manufacturing steps of a particular embodiment of a functionalized material. The functionalized material 20 obtained after these steps is shown in Figure 6.

[0098] According to the example illustrated in Figure 4, the functionalized material 20 comprises a first layer 210 of leather having a first face 216 and a second face 216. The functionalized material 20 further comprises a conductive track 240. Preferably, the conductive track 240 is made of a sheet comprising a conductive metal prepared as described opposite Figure 2 and then deposited by the process described opposite Figures 9 and 10. The functionalized material further comprises an electronic component 250, which is, for example, a transponder. Note at this stage that the thickness of the conductive track 240 is greatly exaggerated to facilitate reading Figures 3 to 6.

[0099] In parallel with the preparation of the first layer, a second layer 220 is worked to create a cavity within it. According to the embodiment shown in Figure 3, the second layer is a layer of leather, for example, split leather, and a cavity 260 is formed in the leather using a laser beam 801 powerful enough to etch the leather. Preferably, the cavity 260 is a blind hole, that is, a non-through hole.

[0100] In other embodiments, at least one cavity is machined into the second layer by other subtractive machining methods, such as sanding or milling. In other embodiments [not shown], at least one cavity has been pre-formed in the second layer using a press or mold.

[0101] In some embodiments, cavities may be cut into the first leather layer and the second layer. Advantageously, these cavities may be aligned to fit together during the assembly of the two layers 210 and 220.

[0102] As illustrated in Figure 5, the first leather layer 210 and the second layer 220 are then placed side by side, taking care to align the components mounted on the first leather layer 210 with the cavities formed in the second layer 220. After applying glue, the two layers are pressed together to obtain the functionalized material shown in Figure 6.

[0103] In embodiments [not shown], the first leather layer 210 and the second layer 220 are held together without glue. In this case, other fastening methods may be used, such as stitching, embossing, or the application of fasteners such as staples. Functionalized material containing cavities

[0104] Figure 7 shows a particular embodiment of a functionalized material 30. The material 30 comprises a first layer 310 of leather, preferably grain leather, and a second layer 320 formed of split leather or grain leather. The second layer has several cavities that house electronic components 351, 352, and 353. At least one conductive track 340, formed by cutting a sheet containing a conductive metal, has been prepared. then deposited between the first and second layers, 310 and 320, then these layers were glued together so as to encapsulate track 340.

[0105] In other embodiments [not illustrated] the first layer and the second layer are both made of grain leather, full-grain leather or corrected grain leather.

[0106] Figure 8 shows a particular embodiment of a functionalized material 40, comprising a first layer 410 of leather and a second layer 420. The functionalized material 40 is distinguished by the fact that it includes several light-emitting diodes 454, 455, and 456 electrically connected to a conductive track 440 formed by a sheet of conductive metal cut by laser or chemical etching and then deposited between the first and second layers, 410 and 420, before these layers are bonded together. The light-emitting diodes are housed in cavities provided in one of the layers 410 or 420.

[0107] In addition, the second layer 420 has three through holes configured to house translucent elements 460, 461 and 462, configured to be placed opposite the diodes 454, 455, and 456, when the two layers, 410 and 420 are assembled together, and configured to allow a glimpse of light emitted by at least one light-emitting diode when the user looks at the external surface 422 of the functionalized material 40. This application allows the integration of a display or an indicator light, for example, into the functionalized material 40. Manufacturing process for a functionalized material

[0108] Figure 9 shows a flowchart illustrating a process 2000 for manufacturing a functionalized material. Figure 10 shows a series of diagrams illustrating the process 2000 for manufacturing a functionalized material. The functionalized material obtained by implementing this process is the functionalized material 50 already described in Figure 2. By implementing certain optional steps detailed below, this process also makes it possible to obtain a functionalized material 60, illustrated in Figure 11.

[0109] The process 2000 includes a step 2005 of supplying a sheet 960 containing a conductive metal. Preferably, the sheet 960 containing a conductive metal is supplied on a first adhesive support 955. For example, the sheet 960 containing a conductive metal is a 35-micron copper sheet coated with a solvent-based, thermosetting, non-conductive acrylic adhesive, supplied on a removable silicone support sheet.

[0110] The 2000 process includes a 2010 step of cutting or engraving the 960 sheet containing a conductive metal to form at least one conductive track or at least one electronic component.

[0111] In embodiments, step 2010 includes a laser engraving step of the sheet 960. A laser beam 802 is emitted onto the sheet 960 and progressively moved to cut a predetermined part of the sheet 960, following a predetermined engraving pattern 930. At the end of this engraving, part of the sheet 960 is removed and the remaining part forms one or more conductive tracks, for example a conductive track 540 forming a spiral is obtained at the end of the laser engraving.

[0112] In some embodiments, step 2010 includes a chemical etching step of the sheet 960. This step consists, for example, of applying a mask [not shown] to protect the parts of the sheet 960 to be retained, according to a predetermined etching pattern. An etching chemical configured to remove the unprotected parts of the sheet 960 is then applied. This etching chemical is, for example, ferric chloride. Following the chemical etching step, a spiral conductive track 540 can, for example, be obtained by applying a suitable etching pattern 930.

[0113] Process 2000 includes a step 2015 of supplying a first layer 510 of leather and supplying a second layer 520. The characteristics of these layers having already been described previously, they are not described again here.

[0114] In some embodiments, the process includes a step 2020 of mounting electronic components onto the cut or engraved sheet 960. According to the example illustrated in Figure 10, a transponder 550 is electrically connected to the inner end of the spiral formed by the conductive track 540 and electrically connected via a jumper 551 to the outer end of the spiral formed by the conductive track 540.

[0115] At this stage, according to a particular embodiment, the conductive track can be protected by adding two layers of polyurethane positioned on either side of the track so as to sandwich it with the electronic component(s), if present. A hot pressing step secures these two polyurethane layers in place. This embodiment will be better understood with reference to Figure 11 and its description.

[0116] The process 2000 includes a step 2025 of positioning the cut or engraved sheet 960 on the first layer 510 of leather or on the second layer 520.

[0117] According to the example illustrated in Figure 10, the conductive track formed in the laser-engraved sheet 960 is transferred onto the first leather layer 510. Advantageously, a transfer support 965 is used to pick up the conductive track 540 obtained by cutting the sheet 960. To do this, the transfer support is brought into contact with the conductive track 540 so that the conductive track adheres to the transfer support 965 and detaches from the adhesive support 955. Then, the assembly formed by the transfer support 965 and the conductive track 540 is pressed against the face 516 of the first leather layer 510. Finally, the support 965 is peeled away from the conductive track 540.11 It is understood that the adhesion with the conductive track 540 with the first adhesive support 955, with the second adhesive support [transfer support] and with the surface 516 of the first layer of leather must be provided to allow the transfer of the track 540 between these supports.

[0118] In some embodiments, the process 2000 includes a step 2030 of hollowing out a cavity in the first layer 510 of leather or in the second layer 520. For example, two cavities 561 and 562 are hollowed out on a first face 521 of the second layer 520. The second face 522 of the layer 522 is the face opposite the face 521; it is the face 522 that will be visible once the fixing step 2040 has been carried out.

[0119] The position and dimensions of these cavities are designed to house protruding elements mounted on the conductive track 540, in particular to house the electronic components 550 and 551. Thus, when mounting the first leather layer 510 with the second layer 520, care must be taken to align the hollowed cavity with the protruding elements that they are to house.

[0120] In some embodiments, process 2000 includes a step 2040 of depositing or applying a product forming a dynamic contact layer.

[0121] Step 2040 involves bringing a liquid or paste product into contact with the conductive track 540. Said product is deposited directly on the conductive track 540 or deposited on at least one of the first layers, 510 and 520, in order to form an interface between the metallic track 540 and at least one of the layers among the first layer 510 and the second layer 520.

[0122] This product is configured to form a dynamic contact layer allowing a sliding movement of the conductive track 540 relative to the first layer 510 and / or relative to the second layer 520. These arrangements make it possible to reduce the mechanical stresses applied by the first layer 510 and / or by the second layer 520 on the metal track 540 during the deformation of the functionalized material 50 during its use.

[0123] The process 2000 includes a step 2050 of fixing the first leather layer 510 to the second layer 520, so as to encapsulate the sheet 960 containing a conductive metal between the two layers. This step 2050 is carried out, for example, by applying a solvent-free leather adhesive to one or both surfaces to be bonded, using a brush or roller, then bringing the surfaces into contact and applying pressure.

[0124] In some embodiments during step 2050, leather adhesive is applied to the surfaces to be bonded, taking care not to apply adhesive to any area intended to receive the conductive track 540. According to this embodiment, if the conductive track 540 is protected by a polyurethane film or hot-pressed between two polyurethane films, then leather adhesive is applied to the surfaces to be bonded, taking care not to apply adhesive to the area intended to be in contact with the polyurethane. Thus, once the conductive track is encapsulated between the two layers, 510 and 520, the conductive track is "floating" between the two layers. This embodiment will be better understood in light of the embodiment described in Figure 11.

[0125] In some embodiments, step 2050 includes an embossing step, a sewing step or a step for applying fastening means to bond the first leather layer 510 with the second layer 520. Depending on the requirements, a combination of these different fastening means may be implemented without deviating from the invention. Functionalized material featuring a floating conductive track

[0126] Figure 11 shows a fourth particular embodiment of a functionalized material 60, the subject of the invention. The functionalized material 60 comprises a first layer 610 of leather and a second layer 620 also of leather.

[0127] The functionalized material 60 houses a conductive track 640 electrically connected to a transponder 650. During manufacturing, the conductive track 640 is obtained by cutting or etching a copper foil or a foil containing another conductive metal. The conductive track 640 is positioned on a first polyurethane film 671 with dimensions slightly larger than the conductive track 640, and then the transponder 650 is electrically connected to the conductive track by bonding it with an anisotropic conductive adhesive. Alternatively, the transponder 650 can be welded onto the conductive track 640. Finally, a second polyurethane film 672 is positioned on the conductive track 640 and the transponder 650, so as to sandwich these elements between the two polyurethane films 671 and 672, and then the whole is hot-pressed using a hot press, at 120°C, for 20 seconds.

[0128] During the manufacture of the functionalized material 60, only a portion of the leather layer 610 is coated with an adhesive 675, for example, a solvent-free leather adhesive. Another portion of the first leather layer 610, with dimensions at least equal to the dimensions of the assembly containing the conductive track 640 in the hot-pressed polyurethane, remains free of adhesive. The assembly containing the conductive track 640 in the hot-pressed polyurethane is placed on the portion of the leather layer free of adhesive, and then the second leather layer 620 is positioned over the first leather layer 610, so as to sandwich the conductive track 640 in the hot-pressed polyurethane. The leather layers 610 and 620 are pressed together to bond them.

[0129] It is emphasized that the layers of leather thus bonded together encapsulate the conductive track 640 in the hot-pressed polyurethane without the said conductive track or the polyurethane being bonded to the first layer of leather 610 or to the second layer of leather 620. The conductive track 640 in the hot-pressed polyurethane is positioned in an intermediate zone 601 delimited at the top and bottom by the leather layers 610 and 620 and on either side by the glue 675 hardened between the leather layers 610 and 620. The conductive track 640 thus positioned is "floating", or "free", that is to say not mechanically attached to the leather layers 610 and 620 and not bonded to these layers.

[0130] It is noted that, in figure 11, the thickness of glue 675 has been greatly exaggerated to facilitate understanding of the diagram.

[0131] Advantageously, as illustrated in Figure 11, the first leather layer 610 and / or the second layer 620 may include a cavity 663 with dimensions substantially larger than the dimensions of the assembly formed by the conductive track 640 in the hot-pressed polyurethane. The cavity 663 is intended to house this assembly. Durability tests - Test conditions

[0132] The inventors designed a durability test and implemented it on functionalized materials according to some of the embodiments described above. This durability test consists of the repeated bending of a fixed sample.

[0133] This durability test aims to simulate the repeated use of a leather item featuring a conductive track as described above. The conductive track serves as an antenna for a transponder configured to communicate wirelessly using NFC technology. Throughout the test, the NFC antenna, also called an NFC "TAG" (from the English "TAG", meaning "label"), is monitored.

[0134] The durability test designed by the inventors uses a VAMP flexometer, conforming to ISO 4643, as a test bench. The VAMP flexometer is typically used to assess crack formation in the flex zone of a shoe during use, in accordance with ISO 4643. This flexometer was originally designed to test the upper part of the shoe's upper, covering the front of the foot, known as the "vamp." The VAMP flexometer consists of several test stations, each with one fixed and one movable lug. Each movable lug is mounted on a slide and configured to perform a constant back-and-forth movement. The gap between the lugs is 28.5 mm + / - 1.0 mm in the open position and 9.5 mm + / - 0.5 mm in the closed position, for a total travel of 19 mm. Each fixed crampon and each mobile crampon has an identical inverted "V" shape with a rounded tip.In other words, each crampon consists of two long, relatively flat sections joined by a curved part. Each crampon is designed to grip (pinch) a piece of leather or other material.

[0135] During the durability test, rectangular samples (test specimens) measuring 7 centimeters by 4 centimeters are tested. A test sample is clamped at both ends, one on a fixed cleat and the other on a movable cleat. One end of the sample is clamped on the fixed cleat at the substantially flat long portion of the cleat, so that the first end of the sample lies flat within the fixed cleat. The second end of the sample is clamped on the movable cleat at the substantially flat long portion of the movable cleat, so that the second end of the sample lies flat within the movable cleat. This configuration differs from a commonly performed "VAMP" test. According to the durability test devised by the inventors, both ends of the sample are clamped flat so that the sample lies substantially flat when the fixed and movable cleats are separated.In contrast, during a "VAMP" test which is usually performed, the sample is folded along the entire length of the cleats so as to conform to the inverted "V" shape of the cleats.

[0136] The durability test of a conductive track as designed by the inventors makes it possible to reproduce the repeated deformations undergone by a flexible article, and particularly a leather article, during the life of said article.

[0137] Throughout the test, a constant back-and-forth movement of the moving crampon folds the leather sample upon itself, forming three creases: a central transverse crease in the center of the sample, and two lateral transverse creases on either side of the central crease. The creases are approximately parallel to each other. Each fold is approximately perpendicular to the axis of movement of the movable clip. Each sample has a conductive track used as an antenna for a transponder, together forming an NFC tag. The NFC tag is positioned at the center of the sample, and is therefore centered on the central transverse fold. The viability of the NFC tag is evaluated throughout the test. Durability testing - sample preparation

[0138] At least one of each of these types of samples is prepared for testing: - TAG-Cu-PU-bonded: Hot-pressed copper conductive track sandwiched between two polyurethane (PU) films, sample bonded to leather, - TAG-Cu-PU-floating: Hot-pressed copper conductive track between two PU films, "floating" sample not bonded to leather, - TAG-Al-PET-bonded: Conductive aluminum track mounted on a polyethylene terephthalate (PET) layer, sample bonded to leather and - TAG-Al-PET-floating: Conductive aluminum track mounted on a layer of polyethylene terephthalate (PET), "floating" sample not glued to leather.

[0139] All samples consist of two rectangular layers measuring 7 centimeters by 4 centimeters. The leather forming the layers is a full-grain black bull calf leather with a thickness of 1.2 mm.

[0140] The bonded TAG-Cu-PU samples consist of a conductive track obtained by laser-cutting a circular antenna pattern from a copper sheet with a thickness between 12 and 30 µm, and a transponder electrically connected to the conductive track by bonding with an anisotropic conductive adhesive. The bonded TAG-Cu-PU samples also include a bridge connecting the two ends of the conductive track forming the antenna. The bonded TAG-Cu-PU samples are prepared according to the steps detailed opposite the description in Figure 11, modified only in that, before encapsulating the hot-pressed conductive track between two polyurethane films, the entire surface of the leather is coated with leather adhesive, and then the leather layers are pressed together to bond them. In this configuration, the hot-pressed conductive track between two polyurethane films is bonded directly to the leather.

[0141] TAG-Cu-PU-floating samples are prepared in the same way as TAG-Cu-PU-bonded samples except that the hot-pressed conductive track between two polyurethane films is not bonded directly to the leather but encapsulated "floating" between the two layers of leather, as detailed in the description of Figure 11, above.

[0142] The TAG-Al-PET-bonded samples are off-the-shelf NFC tags that the inventors have encapsulated between two layers of leather. The NFC tags used are sold under the Sariputa brand name; they consist of a 35-micrometer-thick conductive aluminum track associated with an NTAG215 chip and protected by a polyethylene terephthalate (PET) plastic layer. During the mounting of the NFC tag between the two leather layers, the entire surface of the leather layers to be joined is coated with leather glue, and then the leather layers are pressed together, sandwiching the NFC tag and bonding the PET plastic layer to the leather.

[0143] The floating TAG-Al-PET samples use the same tags as the glued TAG-Al-PET samples. When mounting the NFC tag between two layers of leather, only a portion of the surface of the leather layers to be joined is coated with leather glue, around the perimeter of an area intended to receive the NFC tag. When the two leather layers are pressed together, the PET plastic layer is sandwiched between the two pressed leather layers, in an area free of leather glue. Thus, the NFC tag is not glued directly to the leather but encapsulated and "floating" between the two leather layers. Durability tests - Test results

[0144] The results of the durability tests, under the conditions described above, are presented below. The tested samples were subjected to cycles of spacing and re-spacing the studs at a frequency of 2 hertz until the NFC tag lost its viability or up to 100,000 cycles.

[0145] Throughout the test, the viability of the NFC tag is evaluated. The NFC tag is considered "viable" if it is readable using an NFC chip reader positioned on the test bench during operation. The NFC tag is considered "partially viable" when it can be read using a reader placed in contact with the flat sample outside the test bench. The NFC tag is considered "degraded" when it can be read using a reader placed in contact with the flat sample by pressing on the transponder (chip). Finally, the sample is considered "non-viable" if it is not readable at all using an NFC chip reader positioned in contact with the flat sample, even by pressing on the chip.

[0146] The viability of the NFC tag was verified every 2000 cycles.

[0147] The test results for samples with an NFC tag glued directly onto the leather are presented below in Table 2.

[0148] [Table 2]

[0149] Two samples of glued Cu-PU-TAG are tested; for these samples, total functionality (viable tag) is observed for 2000 and 4000 cycles respectively, followed by a total loss of functionality (non-viable tag), without observation of a partially viable or degraded intermediate state.

[0150] A single TAG-Al-PET-bonded sample is tested. For this sample, a partial viability of the TAG is immediately observed, which is maintained at least up to 4000 cycles, then a total loss of functionality beyond 4000 cycles.

[0151] The test results for samples with a "floating" NFC tag, i.e. not glued to the leather, are presented below in Table 3.

[0152] [Table 3]

[0153] Four floating TAG-Al-PET tags were tested. For each of these samples, the tag degrades or becomes non-viable after just 10,000 cycles. For floating TAG-Al-PET samples #2 and #3, the tag degrades immediately, after fewer than 2,000 cycles. For at least two of the four samples, the performance of the floating samples is better than that of the bonded TAG-Al-PET sample, which is completely degraded (non-viable) after only 4,000 cycles.

[0154] Five floating Cu-PU TAGs were tested. These samples showed particularly satisfactory performance, with tags remaining viable or partially viable until the end of the 100,000 cycles performed during the experiment. Only floating Cu-PU TAG sample #2 showed lower performance, with partial viability up to 30,000 cycles and a complete loss of viability after 50,000 cycles. Microscopic examination of floating Cu-PU TAG sample #2 revealed a probable defect during the bridge mounting step on the conductive track, during which excessive force was likely applied to the conductive track.

[0155] It is noted that TAG-Cu-PU have been tested beyond 100,000 cycles, and up to 200,000 cycles have also shown that their functionality was maintained throughout the test.

[0156] The tests carried out reveal that the tags (the assembly formed by the conductive track and the chip) glued against the leather undergo increased stress during the test which results in the metal of the antenna fracturing compared to the encapsulated "floating" tags between two layers of leather, i.e. without gluing the tag to said layers of leather.

[0157] Specifically, three of the five tested floating TAG-Cu-PU samples retained full (viable tag) or partial (partially viable tag) functionality throughout the entire test period of 100,000 cycles. A fourth floating TAG-Cu-PU sample remained partially viable for 90,000 cycles. In contrast, the two tested bonded TAG-Cu-PU samples experienced a total loss of functionality (non-viable tag) after only 2,000 and 4,000 cycles, respectively.

[0158] Thus, surprisingly, the inventors show that a glue-free structure between the layers of leather and the hot-pressed conductive track between two polyurethane films makes it possible to obtain a functionalized material whose conductive track, or more particularly whose NFC tag [conductive track and chip] is more robust and durable over time.

[0159] One possible explanation for this superior durability is that when the tag is fixed (glued), the leather transmits compression and extension stresses caused by the proximity of the two studs, and also undergoes compression and extension stresses resulting from the bending of the leather sample during flexing. Conversely, when the tag is free-floating (not glued), it is primarily subjected to bending and can deform freely. Consequently, a fixed tag withstands fewer cycles than a free-floating tag; in other words, it breaks sooner.

Claims

DEMANDS 1. Functionalized material characterized in that it comprises: - a first layer made of a primary material which is leather, - a second layer made of a different material, - at least one intermediate zone comprising a metallic track, which has been cut or engraved in a sheet comprising a conductive metal, and possibly at least one electronic component electrically connected to said metallic track, in which said intermediate zone is intercalated between said first layer and said second layer and in which said first and second layers are fixed so as to encapsulate said metallic track and, if present, said electronic component.

2. Functionalized material according to claim 1, wherein said second layer is formed in a second material which is also leather.

3. Functionalized material according to claim 1, wherein said second layer is a layer formed from a material selected from: artificial leather, non-woven textile, natural or synthetic felt, reconstituted leather or oilcloth.

4. Functionalized material according to any one of claims 1 to 3, wherein the difference between the Young's modulus of the first leather layer and the Young's modulus of the second layer does not exceed 0.4 gigapascal, preferably 0.2 gigapascal.

5. Functionalized material according to any one of claims 1 to 4, wherein the intermediate zone comprises a dynamic contact layer allowing movement along the axis of the metallic track relative to the first layer and / or relative to the second layer.

6. Functionalized material according to claim 5, wherein the dynamic contact layer is formed of a contact product selected from a pressure-sensitive adhesive, a latex and an elastomer.

7. Functionalized material according to one of claims 5 or 6, wherein the dynamic contact layer has a Young's modulus between 1 megapascal (MPa) and 1000 MPa, preferably between 1 MPa and 100 MPa.

8. Functionalized material according to any one of claims 1 to 7, wherein at least one layer among the first layer and the second layer has at least one cavity (260) configured to house at least part of an electronic component.

9. Functionalized material according to any one of claims 1 to 8, wherein the intermediate zone comprises a metallic track, cut or engraved in a sheet comprising a conductive metal deposited on a polyurethane support layer.

10. Functionalized material according to any one of claims 1 to 8, wherein the intermediate zone comprises a metallic track, cut or engraved in a sheet comprising a conductive metal hot-pressed between two layers of polyurethane support.

11. Functionalized material according to any one of claims 1 to 10, wherein said first layer and second layer are fixed together on at least a part of the perimeter of the intermediate zone and wherein said metal track and, if present, said electronic component are not glued to said first and second layers.

12. Functionalized material according to any one of claims 1 to 10, wherein said first and second layers are fixed together on at least a part of the perimeter of the intermediate zone and wherein said metal track, the polyurethane support layer(s) and, if present, said electronic component are not bonded to said first and second layers.

13. Functionalized material according to any one of claims 1 to 12, comprising at least one light-emitting diode (454, 455, 456) electrically connected to a conductive track formed in the foil comprising a conductive metal, in which the functionalized material comprises at least one through hole and in which a translucent element configured to allow a glimpse of light emitted by at least one light-emitting diode is positioned in said through hole.

14. A process for manufacturing a functionalized material, characterized in that it comprises: - a step of supplying at least one sheet containing a conductive metal - a cutting or engraving step of said sheet to form at least one conductive track or at least one electronic component - a step involving the supply of a first layer of leather and the supply of a second layer, - a step of positioning said cut or engraved sheet on said first layer of leather or said second layer and - a step of fixing said first layer of leather onto said second layer, so as to encapsulate at least one sheet comprising a conductive metal.

15. Method of manufacturing a functionalized material according to claim 14, wherein the step of cutting or engraving said sheet to form at least one conductive track or at least one electronic component comprises a step of cutting the sheet comprising a conductive metal by laser engraving.

16. Method of manufacturing a functionalized material according to claim 14, wherein the step of cutting or engraving said sheet to form at least one conductive track or at least one electronic component comprises a chemical etching step.

17. Method of manufacturing a functionalized material according to any one of claims 14 to 16, wherein the sheet comprising a conductive metal is supplied on a first adhesive support.

18. A method for manufacturing a functionalized material according to 17, wherein the positioning step of said cut or engraved sheet on said first leather layer or on said second layer involves a transfer of the sheet containing a conductive metal from the first adhesive support to said first leather layer or to said second layer by means of a second adhesive support, referred to as the "transfer support".

19. A method for manufacturing a functionalized material according to any one of claims 14 to 18, comprising a hot-pressing step of the metal track, cut or engraved in a sheet comprising a conductive metal, between two layers of polyurethane support.

20. Leather article comprising a functionalized material according to any one of claims 1 to 13 or obtained by implementing the process for manufacturing a functionalized material according to any one of claims 14 to 18.

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