FUNCTIONALIZED MATERIAL CONTAINING AN ELECTRONIC CIRCUIT PRINTED ON LEATHER AND ENCAPSULATED, ITS MANUFACTURE PROCESS AND ARTICLE CONTAINING SUCH MATERIAL

Abstract

A functionalized material (10) comprising a first layer (110) of leather having a first face (116) and a second face (112), said first face being printed with conductive ink (140, 141) deposited in a predetermined pattern, configured to form at least one electronic component or to electrically connect at least one electronic component, the material further comprising a second layer (120), bonded to the first face of the first layer, so as to encapsulate the conductive ink. A method for manufacturing such a functionalized material and an article comprising such a functionalized material. Figure for the abstract: [Fig 2]

Description

Title of the invention: FUNCTIONALIZED MATERIAL COMPRISING AN ELECTRONIC CIRCUIT PRINTED ON LEATHER AND ENCAPSULATED, 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 material comprising electrical tracks printed directly on a layer of leather and encapsulated between said layer of leather and another layer.

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

[0004] The prior art includes articles and equipment comprising electronic components covered by a layer of leather, such as antennas, switches and other human-machine interface elements, indicator lights, or 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. Leather thus functionalized can be used for integration into dashboards or steering wheels of motor vehicles, or into clothing items, for example.

[0005] Integrating electronic components into a leather article or equipment requires conductive tracks that serve as electrical connections to the electronic elements. These conductive tracks are usually applied to a thin layer of polymer, supplied in the form of a plastic sheet, which also serves as a substrate for the electronic components. This plastic polymer layer carrying the printed circuit board is then covered by a layer of leather, or sandwiched between two layers of leather to form the functionalized leather.

[0006] However, integrating a layer of plastic polymer into a functionalized leather article may result in a less pleasant feel. The polymer layer may also cause a noticeable thickening or alter the mechanical behavior of the Leather. If the leather is made stiffer, it can make the inside-out stitching process difficult—that is, folding the leather to sew a bag from the inside. If the leather is made thicker, it can make it difficult to pass through a calender. 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 does not require a polymer layer as a substrate for the conductive tracks of the electronic circuit it incorporates. The present invention further aims to provide a functionalized material with robust conductive tracks. The inventors have observed that conductive tracks printed on a layer of leather subjected to repeated mechanical deformation do not exhibit good durability. The conductive tracks degrade under stress, causing their electrical resistance to increase excessively, rendering them unusable, or they may break. The present invention aims, in particular, to overcome this limitation.

[0008] To this end, according to a first object, the invention relates to a functionalized material which comprises a first layer of leather having a first face and a second face, said first face being printed with a conductive ink deposited following a predetermined pattern, configured to form at least one electronic component or to electrically connect at least one electronic component, the material further comprising a second layer, glued against the first face of the first layer, so as to encapsulate the conductive ink.

[0009] It is emphasized that the electronic components can be formed, at least in part, by the conductive ink deposited on the first layer, for example in the case of an antenna, or the electronic components can be added parts.

[0010] The term "leather" refers to the material obtained from an animal skin through a tanning process. The leather obtained through tanning has two sides, the first side corresponding to the side of the skin where the hair was implanted, i.e. the top of the skin, and the second side corresponding to the side of the skin that was on the flesh side of the animal.

[0011] In the context of this application, the term "functionalized material" is used to designate a material comprising at least one layer on which is printed at least one conductive track, enabling that material to assume all or part of the function of an electronic device.

[0012] According to the invention, a conductive ink is deposited on the first layer of leather to form conductive tracks. The functionalized material according to the invention overcomes the previously described problem of track degradation. Conductive materials are created by applying a second layer of conductive ink to the first layer of leather after printing. This involves applying an adhesive to at least one of the layers to be bonded, and then pressing them together. The conductive tracks of the functionalized material, thus encapsulated, exhibit significantly improved durability. The electrical resistance of these conductive tracks does not increase beyond an acceptable threshold when the functionalized material is subjected to repeated mechanical deformation.

[0013] Thanks to these arrangements, the functionalized material is durable, that is to say that the electronic circuit which it encapsulates remains functional after several cycles of deformation and then release.

[0014] These provisions are particularly advantageous when the functionalized material is intended to be integrated into an object that is used frequently or even daily and that will be subjected to repeated mechanical stresses. A leather bag incorporating the functionalized material can be cited as an example.

[0015] The better performance of the conductive tracks after deformations of the leather, in particular repeated mechanical bending, could result from a distribution of the stress which is distributed between the first layer of leather and the second layer, when the functionalized material which is the subject of the invention is deformed.

[0016] Preferably, the functionalized material comprises conductive tracks encapsulated 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, that is to say, they can be deformed and then approximately return to their initial structure and retain their functionality.

[0017] Thus, "flexible" describes a functionalized material, a layer, a conductive track, or an electronic circuit that is not rigid, brittle, or stiff, but that bends, stretches, changes shape, or is subjected to external forces without breaking or losing its functionality when subjected to such external forces. A flexible circuit or electronic component, or a flexible conductive track, is understood to be an electronic circuit or conductive track 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 retain its conductivity even when deformed under a longitudinal strain stress of between 10% and 40%, between 10% and 30%, or between 10% and 20%.

[0018] In some embodiments, said second layer is a leather layer.

[0019] The inventors discovered that the nature of the second layer influences the previously described effect of preserving the conductive tracks. In particular, encapsulating the conductive tracks between two layers of leather gave results satisfactory on the preservation of conductive tracks and / or components formed by conductive tracks.

[0020] The rigidity of the material forming the second layer appears important for achieving the conductive track preservation effect. The inventors discovered that a fairly similar rigidity between the two layers allows for a better conductive track preservation effect. Young's modulus, also called the tensile modulus or longitudinal modulus of elasticity, is used to characterize this rigidity.

[0021] 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, preferably 0.2 GPa.

[0022] 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.

[0023] In some embodiments, the second layer is made of artificial leather, for example, artificial leather made of synthetic fibers bonded together by a resin. For example, the artificial leather is Alcantara artificial leather (registered trademark), which comprises layers of polyester synthetic fibers bonded together by the hot application of a polyurethane resin.

[0024] In 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.

[0025] 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.

[0026] In some embodiments, the second layer is reconstituted leather. The reconstituted leather can be made from ground leather fibers that are then glued together and / or glued onto a mesh or paper fiber.

[0027] In other embodiments, the second layer is a waxed canvas.

[0028] The present invention incidentally aims to integrate electronic components into the material while maintaining a pleasant feel. In order to achieve this result, the applicant company found it important that the user not perceive not by touch of the reliefs betraying the presence of the components under the leather, when using the functionalized material.

[0029] 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.

[0030] Thanks to these arrangements, the thickness of the functionalized material remains substantially the same, making it possible to avoid the presence of unpleasant reliefs to the touch.

[0031] In embodiments, the functionalized material comprises at least one light-emitting diode (LED) electrically connected to the conductive ink deposited on the first leather layer, 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.

[0032] These provisions allow the integration of light sources visible to the user into the functionalized leather.

[0033] In some embodiments, the conductive ink is printed onto the first layer of leather by screen printing.

[0034] Preferably, the conductive ink used to print the conductive tracks is an ink containing metallic particles such as silver or copper flakes in a retaining matrix, or carbon flakes / particles in a retaining matrix. Inks containing conductive particles with a different geometry, such as nanowires, may advantageously be used. The particles in these inks overlap when the ink is deposited on the leather, thus limiting the increase in electrical resistance during mechanical deformation of the functionalized material. Consequently, the conductive tracks formed by these inks exhibit greater durability. However, this type of ink has an intrinsically higher electrical resistance than solid materials.

[0035] In other embodiments, the conductive ink is printed onto the first leather layer by inkjet printing, gravure printing, or flexography. According to an alternative embodiment, a layer of conductive ink is deposited on the surface of the first leather layer, and then conductive tracks are formed by laser engraving the conductive ink deposit.

[0036] In some embodiments, the first leather layer is a layer of goatskin. Leathers from different animals do not have the same roughness, presumably due to different fiber structures and the presence of cavities that affect the electrical resistance of the conductive tracks. The Deposition of conductive track on a first layer of leather made from goatskin showed satisfactory results.

[0037] In embodiments, the first layer of leather, on which the conductive ink is printed, is a layer of grain leather obtained from splitting a leather.

[0038] In the leather industry, splitting is the process of separating the leather obtained after tanning into two layers, resulting in two pieces of leather of roughly the same size as the tanned leather, but thinner. Splitting produces a first layer called the grain of the leather and a second layer called the split leather. The split leather is the layer of leather obtained after splitting that includes the side of the hide that was on the flesh side of the animal. The grain of the leather is the layer of leather obtained after splitting that includes the side of the hide where the hair was embedded.

[0039] The split leather is therefore a layer of leather from the part of the hide located on the side of the animal's flesh and the grain leather is a layer from the part of the leather located on the side where the hairs were implanted.

[0040] Full-grain leather is generally denser than split leather. It is also considered more refined, being more durable than split leather and aesthetically pleasing. Split leather is less dense and less uniform, is generally less durable, and is considered aesthetically different from full-grain leather.

[0041] A layer corresponding to the grain of the leather can be a layer of full-grain leather or a layer of corrected grain leather. A layer of full-grain leather corresponds to a whole grain of leather, that is to say, whose surface has not been reworked, for example by sanding to remove imperfections. Conversely, a layer of corrected grain leather generally corresponds to a grain of leather that has been thinned by sanding or by other methods in order to remove imperfections in the leather.

[0042] Thus, according to a particular embodiment of the invention, the conductive ink is printed on a first layer of leather which is a grain of leather, that is to say a full grain leather or a corrected grain leather.

[0043] The inventors have determined that printing conductive ink on the grain of leather makes it possible to obtain conductive tracks of better quality, i.e. whose electrical resistance is less degraded when the functionalized material is subjected to deformations.

[0044] According to a second aspect, the invention relates to a method for manufacturing a functionalized material, the method comprising the following steps: - the supply of a first layer of leather comprising a first face and a second face, - the printing of conductive ink on the first side of the first layer of leather, to form at least one electronic component or to electrically connect at least one electronic component, - the supply of a second layer and - a step of gluing the second layer against the first face of the first layer, so as to encapsulate the conductive ink.

[0045] In some embodiments, the printing of the first side of the first layer of leather with conductive ink is carried out by a screen printing method which comprises the following steps: - the application of a screen printing mask against the first side of the first layer of leather, - the application of conductive ink onto the screen printing mask and the transfer of the ink through the mask to the first face of the first layer of leather by means of a roller or a squeegee and - the removal of the mask.

[0046] In some embodiments, annealing of the deposited conductive ink is necessary. Preferably, the annealing step is carried out by applying a stream of hot air to the conductive ink. The air stream is, for example, at a temperature between 85°C and 115°C, preferably between 95°C and 115°C, for a time between 6 and 10 minutes.

[0047] Thanks to this arrangement, annealing can be carried out by applying an airflow only to the areas where conductive ink has been deposited. This avoids heating other parts of the leather. It also makes it possible to perform the annealing step on large layers of leather, for example, on the order of one meter by one meter and containing multiple electronic circuits, without requiring a large oven.

[0048] Alternatively, annealing can be carried out using an infrared radiation source, which has similar advantages, or using a furnace.

[0049] The characteristics previously described with regard to the functionalized material which is the subject of the invention may advantageously be integrated into the manufacturing process of such a material, which is the subject of the present invention.

[0050] Since certain advantages, purposes and characteristics of the manufacturing process of a material that is the subject of the invention are identical to those already described above concerning said functionalized material, they are not recalled here.

[0051] 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.

[0052] By way of example, the article is a leather goods article which includes a functionalized leather having an antenna and forming part of the leather or lining of the leather goods article.

[0053] By way of example, the article is an interior decoration element of a vehicle which includes a functionalized leather forming a covering for an armrest or steering wheel, for example.

[0054] By way of example, the conductive ink forms or connects at least one electronic component chosen from among an antenna, a switch, a touch surface or other human-machine interface element, an indicator light or a display element.

[0055] Advantageously, the electronic component formed by the conductive tracks is an antenna enabling short-range wireless communication, for example, NFC (Near-Field Communication). 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.

[0056] 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

[0057] 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 the process which are the subject of the present invention, with reference to the accompanying drawings, in which:

[0058] [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.

[0059] [Fig.2] represents, schematically and in side view, a first particular embodiment of a functionalized material which is the subject of the invention.

[0060] [Fig.3] schematically represents a cavity-cutting step during the manufacture of a functionalized material according to a second particular embodiment of the invention.

[0061] [Fig.4] schematically represents the first leather layer of the second embodiment of the functionalized material, during its manufacture.

[0062] [Fig.5] schematically represents the step of bonding the functionalized material according to the second embodiment of the invention.

[0063] [Fig.6] represents, schematically and in cross-sectional view, the material functionalized according to the second embodiment of the invention.

[0064] [Fig.7] shows a photograph, taken from above, of the first layer of leather schematically represented in [Fig.4].

[0065] [Fig.8]] represents, schematically and in cross-sectional view, a second a particular embodiment of a functionalized material which is the subject of the invention.

[0066] [Fig.9] represents, schematically and in cross-sectional view, a third a particular embodiment of a functionalized material which is the subject of the invention.

[0067] [Fig. 10] represents, in the form of a logic diagram, a particular embodiment of a manufacturing process for a functionalized material that is the subject of the invention.

[0068] The reference numbers mentioned in the figures refer to: 10, 20, 30, 40 functionalized material 110, 210, 310, 410 first layer of leather 112, 212, 312, 412 second side of the first layer of leather 116, 216, 416 first face of the first layer of leather 120, 220, 320, 420 second layer 121, 221, 321, 421 first face of the second layer 122, 222, 322 second face of the second layer 140, 141, 240, 340, 440 conductive ink 250, 351, 352, 353 electronic component 454, 455, 456 light emitting diode 260 cavity 801 Laser Beam 910 grain leather 911 full bloom 912 outer surface of the leather grain 915 flower corrected 916 inner surface of the leather grain 920 leather split 921 outer surface of the leather grain 922 inner surface, or flesh side, of the leather crust DETAILED DESCRIPTION OF THE INVENTION

[0069] The present description is given by way of non-limiting grammar, each feature of an embodiment being able to be advantageously combined with any other feature of any other embodiment.

[0070] Figure [1] shows a side view of layers 910 and 911 resulting from the splitting of a cowhide.

[0071] Layer 910 is the grain of the leather; it is the part located on the side where the hairs were implanted, obtained after splitting the leather. It is shown here in When cut, revealing surface 912, which corresponds to the outermost layer of the epidermis, surface 912 is preferentially left exposed on a leather item, as it offers the most pleasant feel and can reveal the natural grain of the leather. Within the grain of 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 portion closest to the epidermis has been retained. On the other hand, corrected grain 915, which corresponds to a grain of leather whose thickness closest to the epidermis has been sanded to remove imperfections. The grain of leather 910 has a second side 916, which can be called the "corrected grain side" or "flesh side."

[0072] Layer 920 is the leather split, which is the part in contact with the animal's flesh, obtained after splitting the hide. The leather split 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.

[0073] Figure 2 shows a functionalized material 10 represented in a partially exploded view.

[0074] The material 10 comprises a first layer 110 of leather, preferably a grain leather layer, for example, a grain leather of the type illustrated in [Fig. 1]. The first layer 110 has a first face 116 and a second face 112. The second face 112 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 116 is the face opposite the second face. On the first face, a conductive ink 140, 141 has been deposited. This conductive ink forms electrically conductive tracks that form all or part of electronic components, or connect electronic components together, or connect electronic components to a current source.

[0075] The ink used to print the tracks may be an ink containing silver particles, copper particles, or graphite. For example, the conductive ink used is SILVER ELECTRON FLEX ink (registered trademark) containing silver particles, marketed by VFP Ink Technologies. For example, the conductive ink used is Nanopaint's BSInkO2NP ink (registered trademark) containing silver particles, marketed by nanoPAINT.

[0076] Two conductive tracks, 140 and 141, are shown here, without detailing the electronic circuit they form. This could be, for example, a switch, a touch surface, another human-machine interface element, an indicator light, a display element such as an LED matrix, or a combination of these elements.

[0077] The first leather layer 110 and the second layer 120 are shown here separately. To form the functionalized material, the two layers are joined together, preferably by means of an adhesive (not shown) and by bringing them into contact. A first face 121 of the second layer is thus brought into contact with the first face 116 of the first leather layer. The manufacture of the functionalized material will be better understood with regard to the description of the following figures, in particular with regard to [Fig. 10].

[0078] Preferably, the second layer 120 is made of leather, for example, full-grain or split leather. Alternatively, the second layer is made of another material. Preferably, this is a material with 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, or synthetic felt.

[0079] After the first leather layer is joined to the second layer, the conductive tracks are encapsulated. This operation increases the durability of the tracks, as demonstrated by durability tests carried out by the inventors. Durability tests

[0080] A durability test was carried out on conductive tracks printed on different substrates (layer or assembly of layers).

[0081] For each test, a test specimen was produced. The specimen is formed from a layer of the material to be tested and comprises a thin central section and two larger end sections. Prior to the test, a conductive track is printed on the central section. During the test, the two end sections of the specimen are held by clamps 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 the cylindrical solid applies a downward force at a right angle to the central section of the specimen, deforming it. At each cycle, a force of 0.5 Newtons is applied, after which the solid is lifted. The applied force causes a vertical displacement of 14 millimeters. Ten thousand cycles of deformation and release are performed during the test.

[0082] 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 resistance value measured during the test, divided by the initial resistance Ro, is denoted R / Ro. The maximum value R / Ro Max of the R / Ro ratio measured during the test indicates the degradation of the conductive tracks: the higher this value, the more degraded the tracks. Furthermore, a resistance measurement is taken 24 hours after the test to assess the capacitance of the conductive tracks. to regenerate during a rest period, that is, without new mechanical stresses applied to the test specimens.

[0083] Four test specimens are manufactured to perform the test: Two specimens consist of a single layer of split leather, respectively bovine and goatskin. On these specimens, the steps of applying a first layer and printing a conductive ink, as described opposite [Fig. 10], are carried out. Two other specimens are manufactured; on these, printing is performed on split leather according to the same steps as for the previous specimens, then during a step of applying a second layer, a second layer of grain leather is applied, and then the first and second layers are bonded together so as to encapsulate the conductive tracks.

[0084] The results of the durability test are presented in Table 1 below. For the test on a specimen with a single layer of bovine split leather, a very high R / Ro ratio (117) is achieved; the resulting resistance of the conductive track does not allow its use in an electrical circuit. As for the specimen with a single layer of goat split leather, the conductive track is irreparably damaged at the end of the test.

[0085] With regard to the test specimens having tracks encapsulated between two layers of bovine leather and between two layers of goatskin leather, much lower maximum R / Ro ratios are reached, respectively of 2.35 and 9.72. In addition, it is observed that the conductive tracks regenerate: the R / Ro ratios measured again 24h after the test reveal a return to the initial resistance for the encapsulated bovine leather test specimen, and a return to an R / Ro ratio of 2.87 for the encapsulated goatskin test specimen.

[0086] [Tables 1] R / Ro layer or layer assembly one day after the R / Ro Max test: Cowhide split 2.66 117; Cowhide encapsulated 1 2.35; Goathide split -; Goathide encapsulated 2.87 9.72

[0087] Figures 3, 4, and 5 illustrate the manufacturing steps of a particular embodiment of a functionalized material. The functionalized material 20 obtained at the end of these steps is illustrated in Figure 6.

[0088] The functionalized material 20 comprises a conductive ink 240 forming a spiral, illustrated in [Fig. 5], which serves as an antenna for a transponder 250 configured to communicate wirelessly using NFC technology (abbreviated from the English " Near Field Communication (NFC). Conductive ink 240 is printed onto a first face 221 of a first layer of leather 220. The transponder 250 is positioned on the first face 221 or attached to it. An electrical connection is made between the transponder 250 and the spiral of conductive ink. This connection can be made using conductive ink, conductive adhesive, or any other suitable electrical conductor. These steps result in a first layer of leather carrying an NFC antenna, as shown in [Fig. 4] and [Fig. 7]. Note that the thickness of the conductive ink deposit is greatly exaggerated here to make it visible.

[0089] At the same time, a second layer 220 is worked to create a cavity in it. According to the embodiment shown in [Fig. 3], the second layer is a layer of leather, for example, split leather, and a cavity 260 is formed in the leather by means of a laser beam 801 powerful enough to carve through the leather. Preferably, the cavity 260 is a blind hole, i.e., a non-through hole.

[0090] In other embodiments, at least one cavity is hollowed out in the second layer by other subtractive machining methods, such as sanding or milling.

[0091] In other embodiments (not shown), at least one cavity has been previously formed in the second layer by means of a press or a mold.

[0092] In some embodiments, cavities may be cut into the first leather layer and the second layer. Advantageously, these cavities may be aligned so as to be joined when the two layers are assembled.

[0093] As illustrated in [Fig.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 application of glue, the two layers are pressed together to obtain the final functionalized material shown in [Fig.6].

[0094] Figure 8 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. On one face of the first leather layer 310, conductive ink has been applied according to a predetermined pattern. It should be noted that, according to this configuration, the conductive tracks are printed on the first face 316 of the first grain leather layer, while allowing the second face 312 of the grain leather to be presented to the user of the functionalized material.

[0095] 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.

[0096] Figure 9 shows a particular embodiment of a functionalized material 40, which comprises a first leather layer 410 and a second layer 420. The functionalized material 40 is distinguished in that it comprises several light-emitting diodes 454, 455, and 456 electrically connected to conductive ink 440 deposited on a first face 416 of the first leather layer. The light-emitting diodes are housed in cavities provided in one of the layers 410 or 420.

[0097] 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 with each other, 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 makes it possible to integrate into the functionalized material 40 a display or an indicator, for example.

[0098] Figure 10 shows a flowchart illustrating a process for manufacturing a functionalized material.

[0099] The process 1000 includes a step 1005 of supplying a first layer of leather having a first face and a second face. Preferably, the first layer of leather is a grain leather.

[0100] The process 1000 includes a step 1010 of printing a conductive ink onto the first side of the first leather layer. This step is preferably carried out by screen printing; it allows for the formation of at least one electronic component and / or enables the electrical connection of at least one electronic component.

[0101] In the case where the printing of the first side of the first layer of leather with a conductive ink is carried out by a screen printing method, the printing may include the following steps: - the application of a screen printing mask against the first side of the first layer of leather, - the application of conductive ink onto the screen printing mask and the transfer of the ink through the mask to the first face of the first layer of leather by means of a roller or a squeegee and - the removal of the mask.

[0102] In some embodiments, annealing of the deposited conductive ink is necessary. Preferably, the annealing step is carried out by applying a stream of hot air to the conductive ink. The air stream is, for example, at a temperature between 85°C and 115°C, preferably between 95°C and 115°C, for a time between 6 and 10 minutes. In other embodiments, a conductive ink that dries at a temperature below 100°C, for example at a temperature of 60°C.

[0103] The process 1000 includes a step 1015 of supplying a second layer which is preferably a layer of leather, for example of split leather or of other materials whose rigidity is close to that of leather.

[0104] In some embodiments, the process 1000 comprises a step 1025 of excavating at least one cavity and a step 1030 of installing a component in the excavated cavity. This step has previously been described with reference to [Fig. 3] in particular.

[0105] The process 1000 includes a step 1040 of bonding the second layer to the first face of the first layer, so as to encapsulate the conductive ink. This step 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 to be bonded into contact and applying pressure.

Claims

Demands

1. A functionalized material (10, 20, 30, 40) characterized in that it comprises a first layer (110, 210, 310, 410) of leather having a first face (116, 216, 316, 416) and a second face (112, 212, 312, 412), said first face being printed with conductive ink (140, 141, 240, 340, 440) deposited in a predetermined pattern, configured to form at least one electronic component or to electrically connect at least one electronic component (251, 351, 352, 353, 454, 455, 456), the material further comprising a second layer (120, 220, 320, 420) bonded to the first face of the first layer, so to encapsulate the conductive ink.

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

3. Functionalized material according to claim 1, wherein said second layer is a layer which has a Young's modulus between 0.1 gigapascal and 0.8 gigapascal, preferably between 0.2 gigapascal and 0.6 gigapascal, preferably between 0.25 gigapascal and 0.55 gigapascal.

4. Functionalized material according to claim 1, 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 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.

6. Functionalized material according to any one of claims 1 to 5, comprising at least one light-emitting diode (454, 455, 456) electrically connected to the conductive ink deposited on the first leather layer, wherein the functionalized material comprises at least one through hole and wherein a translucent element configured to allow a glimpse of light emitted by at least one light-emitting diode is positioned in said through hole.

7. Functionalized material according to any one of claims 1 to 6, wherein the conductive ink is printed on the first leather layer by screen printing.

8. Functionalized material according to any one of claims 1 to 7, wherein the first layer of leather, on which the conductive ink is printed, is a layer of grain leather obtained from splitting a leather.

9. A method for manufacturing a functionalized material, the method being characterized in that it comprises the following steps: - providing a first layer of leather having a first face and a second face, - printing a conductive ink on the first face of the first layer of leather, to form at least one electronic component or to electrically connect at least one electronic component, - providing a second layer and - a step of gluing the second layer against the first face of the first layer, so as to encapsulate the conductive ink.

10. Leather article comprising a functionalized material according to any one of claims 1 to 8 or obtained by implementing the process for manufacturing a functionalized material of claim 9.

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