Electrical cables and accessories comprising an insulating system including solid fillers based on a cross-linked polymer

Abstract

The invention relates to an electrical cable (10) comprising a conductive core (7) and an insulating system (9) surrounding said conductive core (7), and wherein the insulating system comprises at least one layer (8) comprising a polymer matrix (11) in which solid particles (3) of cross-linked polymer, advantageously derived from recycling, are dispersed. Single figure

Description

Title of the invention: Electrical cables and accessories comprising an insulating system including solid fillers based on a cross-linked polymer

[0001] The invention relates to the field of electrical cables of the type comprising an insulating system surrounding an electrically conductive element (also referred to by the generic term "conductive core") and accessories associated with such cables. More specifically, the invention relates to a new type of insulating system comprising a particular solid filler, which may advantageously be derived from recycling.

[0002] Many electrical cables manufactured and used worldwide consist of one or more elongated conductive elements forming a conductive core and an insulating system surrounding this conductive core. Cable accessories incorporating an insulating system are also known. For the purposes of this description, cable accessories include the well-known splicing (connection between two cables), distribution (connection between a primary cable and several distribution cables), and termination (at the end of a single cable) devices. Many cable and cable accessory insulation systems are based on one or more cross-linked layers (deposited around the conductive core for a cable and around the connection or termination for an accessory).Typically, these insulating systems are based on at least one cross-linked polymer material, notably a cross-linked polyolefin such as, for example, cross-linked polyethylene (XLPE) and / or an elastomer. In general, the insulating system for electrical cables is formed by hot extrusion of a thermosetting composition.

[0003] Such extrusion necessarily results in the formation of waste, particularly production waste or extruder purge waste. This waste contains cross-linked polymers that cannot be reused and / or reshaped by conventional thermomechanical extrusion and / or injection processes and constitutes waste that is only minimally or not at all recovered, except for energy production, for example, from XLPE purges. For the most part, this waste is destined for costly disposal in specialized facilities that meet environmental standards.

[0004] Similarly, the insulating system of end-of-life electrical cables also constitutes waste containing cross-linked polymer materials which also need to be treated (inerting of end-of-life electrical cables).

[0005] A major drawback of crosslinked polymer materials is that they are not directly recyclable, unlike thermoplastic polymers which can They can be reshaped by heating. Due to their cross-linking, cross-linked polymer materials have a fixed three-dimensional structure that cannot be modified by heat treatment.

[0006] One object of the present invention is to provide a way to eliminate the need to process scrap and waste based on the aforementioned cross-linked polymers, thereby avoiding the associated costs, for example during cable manufacturing (processing of production scrap and purges) or subsequently, during the inerting of end-of-life electrical cables.

[0007] To this end, the present invention proposes a means of valorizing scrap and waste based on crosslinked polymers.

[0008] To this end, the present invention proposes to reduce to solid particles the crosslinked polymers of the type present in the aforementioned scrap and waste, and to use the crosslinked polymer particles thus obtained as a solid particulate filler in insulating layers of electrical cable or electrical cable accessories.

[0009] More specifically, the present invention relates to an electrical device equipped with an insulating system, said device being an electrical cable or an accessory for an electrical cable, and wherein the insulating system of the device includes at least one layer comprising a polymer matrix in which solid particles of cross-linked polymer are dispersed.

[0010] According to a first aspect, the invention relates to a device of this type which is an electrical cable comprising a conductive core and an insulating system surrounding said conductive core, and in which the insulating system comprises at least a polymer matrix in which solid particles of cross-linked polymer are dispersed.

[0011] For the sake of brevity, the layer of the insulating system comprising the solid particles of crosslinked polymer according to the invention is designated in this description by the generic term "composite polymer layer".

[0012] Unexpectedly, the inventors have now demonstrated that solid particles based on crosslinked polymers, in particular based on XLPE, obtained for example by grinding materials from waste materials from the preparation of crosslinked layers of cables and / or crosslinked insulating layers of cables at the end of their life, can be used as particulate solid fillers in insulating layers of electrical cables or electrical cable accessories.

[0013] The invention takes advantage of this interest in solid particles based on crosslinked polymers. In this context, the invention notably allows for the preservation and / or protection of the environment by providing an outlet for the valorization of crosslinked polymer materials which, from a state of waste with no intrinsic value, or even associated with a cost for its treatment (inerting, incineration), pass, as a result of the invention, into a state of high value-added product.

[0014] In the cable according to the invention, the insulating polymer layer present in the insulating system comprises cross-linked polymer particles as a solid filler. These particles comprise (or are entirely made up of) at least one cross-linked polymer material. Advantageously, these are particles of a recycled polymer material, which are generally obtained from the grinding and / or micronization of waste or scrap based on one or more cross-linked polymers (in particular, scrap obtained during the preparation of an electrical cable or end-of-life cable waste).

[0015] Regardless of their exact nature, the crosslinked polymer particles are dispersed throughout the volume—in particular throughout the entire volume—of the polymer matrix of the layer. This dispersion within the volume of the polymer matrix is ​​preferably homogeneous.

[0016] Furthermore, the solid charge particles that are dispersed in the matrix preferably have a median size d50 in mass and / or a median size d50 in volume of between 10 and 1000 pm, this median size d50 in mass and / or in volume typically being between 50 and 700 pm, for example between 100 pm and 500 pm.

[0017] In this description: The term "conducting core" of an electrical cable refers to an elongated electrically conductive element extending substantially axially along the longitudinal axis of an electrical cable, or a set of such elongated electrically conductive elements (which may be bundled together, for example, in the form of a strand). An elongated electrically conductive element within the conducting core typically comprises a material that carries the electric current, for example, a metal, particularly copper or aluminum, or one of their alloys. The material constituting an elongated electrically conductive element within the conducting core preferably has a resistivity at 20°C less than or equal to approximately 1.7 x 10⁶ Ωm, and preferably less than or equal to 1.7 x 10⁸ Ω.Approximately m, - the terms "under" and "below" define the relative position of a first element or first polymer layer with respect to a second element or second polymer layer. The first element or first polymer layer is located under / below the second element or second polymer layer, which is positioned between the second element or second polymer layer and the conductive core. The terms "under" and "below" are therefore understood in the axial direction of the cable, with the conductive core as the reference: when the description refers to a first layer deposited on the conductive core and under a second layer, this means that the first layer surrounds the core and the second layer surrounds the first layer (and the core it contains). The terms "under" and "below" indicate relative positions and do not imply that a layer deposited under another is necessarily in direct physical contact with it. - The expression "around the conductive core" refers to the relative position of an element, particularly a polymer layer, with respect to the conductive core. The element or polymer layer covers the conductive core, although this element or polymer layer is not necessarily in direct contact with the conductive core. One or more elements or layers may or may not be interposed between the conductive core and the polymer layer. - The expression "directly covering" defines the position of a first element or first polymer layer with respect to a second element or second polymer layer, whereby the first element or first polymer layer is directly above the second element or second polymer layer, without any other element or polymer layer being interposed between the first element or first polymer layer and the second element or second polymer layer.

[0018] Throughout this text, the terms "recycled material," "recycled polymer material," and "recycled cross-linked polymer material" refer to a material, a polymer, and a cross-linked polymer recovered from post-consumer waste and / or industrial waste, and which therefore no longer constitute waste. "Post-consumer waste" is understood to mean an object that has become obsolete or is at the end of its life, that is, an object that has completed a use cycle or life cycle and is intended for disposal. "Industrial waste" is understood to mean production by-product that has not completed such a use cycle. According to the invention, industrial waste can be production waste or extrusion purge.

[0019] The particle size of the solid filler used according to the invention can be evaluated prior to the dispersion of said solid filler in the polymer matrix, by any method known per se. The median size (d50) by mass of the particles of the particle composition intended to form said solid filler is determined by successive sievings, in particular by successive sievings on vibrating sieves of decreasing mesh size and analysis by mass or volume of the particles retained on each of the sieves, the median size (d50) by mass or volume of the particles of the particle composition intended to form said solid filler corresponding to a particle size such that 50% (by mass or volume) of the particles of the composition have a size greater than or equal to the median size and 50% (by mass or volume) of the particles of the composition have a size less than or equal to the median size.In some embodiments, the size in number, mass, or volume of the particles in the particle composition intended to form said solid charge can be determined by laser diffraction. In some embodiments, the size in number, mass, or volume of the particles in the... The composition of particles intended to form said solid charge can be determined by morpho-granulometric analysis using 2D imaging with image recognition.

[0020] Preferably, to determine a median size (d50) by mass, the aforementioned method of successive sievings (the so-called "sieve method") is used according to the invention.

[0021] When it comes to determining a median size by volume, the preferred method is that which involves the analysis of the particle size distribution, in particular by the aforementioned methods.

[0022] The size dlO in mass or in volume of the particles of the particle composition intended to form said solid charge corresponds to a particle size such that 90% (in mass or in volume) of the particles of the composition have a size greater than or equal to the size dlO and 10% (in mass or in volume) of the particles of the composition have a size less than or equal to the size dlO.

[0023] The size d90 in mass or in volume of the particles of the particle composition intended to form said solid charge corresponds to a particle size such that 10% (in mass or in volume) of the particles of the composition have a size greater than or equal to the size d90 and 90% (in mass or in volume) of the particles of the composition have a size less than or equal to the size d90.

[0024] The size d99 in mass or in volume of the particles of the particle composition intended to form said solid charge corresponds to a particle size such that 1% (in mass or in volume) of the particles of the composition have a size greater than or equal to the size d99 and 99% (in mass or in volume) of the particles of the composition have a size less than or equal to the size d99.

[0025] According to certain embodiments, at least 100%, or at least 90%, or at least 80%, or at least 70%, or at least 60%, or at least 50%, or at least 40%, or at least 30%, or at least 20%, or at least 10% by mass or by volume, particles of at least one crosslinked polymer material have a larger dimension between 10 pm and 1000 pm.

[0026] According to certain embodiments, 100%, or at least 90%, or at least 80%, or at least 70%, or at least 60%, or at least 50%, or at least 40%, or at least 30%, or at least 20%, or at least 10% by mass or by volume, particles of at least one crosslinked polymer material have two dimensions greater than one smaller dimension, the two dimensions greater than the smaller dimension each being between 10 pm and 1000 pm, the two dimensions greater than the smaller dimension extending along directions orthogonal to each other and orthogonal to the direction of the smaller dimension.

[0027] According to certain embodiments, at least 100%, or at least 90%, or at least 80%, or at least 70%, or at least 60%, or at least 50%, or at least 40%, or at least 30%, or at least 20%, or at least 10% by mass or volume, particles of at least one crosslinked polymer material have three dimensions extending along three directions orthogonal to each other, the three dimensions being between 10 pm and 1000 pm, in particular between 50 and 500 pm, and for example between 100 and 500 pm.

[0028] According to some embodiments, the particles of at least one crosslinked polymer material are micronized particles.

[0029] In some embodiments, said solid charge is formed of particles with a median size d50 by mass and / or volume not exceeding 1000 µm. In some embodiments, said solid charge is formed of particles with a median size d50 by mass and / or volume between 10 µm and 1000 µm, in particular between 50 and 500 µm, and for example between 100 and 500 µm. In some embodiments, said solid charge is formed of particles with a median size d50 by mass and / or volume between 100 µm and 200 µm. In some embodiments, said solid charge is formed of particles with a median size d50 by mass and / or volume between 200 µm and 300 µm. According to some embodiments, said solid charge is formed of particles of median size d50 in mass and / or volume, between 300 pm and 400 pm.In some embodiments, the solid charge is formed of particles with a median size d50 by mass and / or volume, between 400 µm and 500 µm. In these embodiments, the solid charge is formed of particles with a median size d90 by mass and / or volume, on the order of 500 µm. In these embodiments, the solid charge is formed of particles with a median size d99 by mass and / or volume, on the order of 630 µm. In some embodiments, the solid charge is formed of particles with a median size d50 by mass and / or volume, between 500 µm and 600 µm. In some embodiments, the solid charge is formed of particles with a median size d50 by mass and / or volume, between 600 µm and 700 µm. According to some embodiments, said solid charge is formed of particles of median size d50 in mass and / or volume, between 700 pm and 800 pm.According to some embodiments, said solid charge is formed of particles with a median size d50 by mass and / or volume, between 800 pm and 900 pm. According to some embodiments, said solid charge is formed of particles with a median size d50 by mass and / or volume, between 900 pm and 1000 pm.

[0030] The particle size of said solid filler dispersed in the polymer matrix of the composite polymer layer can be determined by any method known per se. The particle size of at least one cross-linked polymer material of said solid filler of the composite polymer layer can be assessed by direct visual observation of at least one cross-section (transverse, longitudinal, or beveled) of the insulating system of the electrical cable or electrical cable accessory, or by means of a magnifying optical device. It can be measured in a Indirectly, by acquiring digital images of such a section and analyzing the acquired images, a median size in number can be deduced from these measurements.

[0031] According to certain embodiments, at least 50%, or at least 55%, or at least 60%, or at least 65%, or at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95%, or at least 96%, or at least 97%, or at least 98%, or at least 99%, in particular 100% by number, of the particles of at least one crosslinked polymer material of said solid filler of the composite polymer layer are particles having a larger dimension between 10 pm and 1000 pm, in particular between 50 and 500 pm, and for example between 100 and 500 pm.

[0032] According to certain embodiments, at least 50%, or at least 55%, or at least 60%, or at least 65%, or at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95%, or at least 96%, or at least 97%, or at least 98%, or at least 99%, in particular 100% by number, of the particles of at least one crosslinked polymer material of said solid filler of the composite polymer layer are particles having a larger dimension between 10 pm and 500 pm.

[0033] According to certain embodiments, at least 50%, or at least 55%, or at least 60%, or at least 65%, or at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95%, or at least 96%, or at least 97%, or at least 98%, or at least 99%, in particular 100% by number, of the particles of at least one crosslinked polymer material of said solid filler of the composite polymer layer are particles having a larger dimension between 10 pm and 50 pm.

[0034] According to certain embodiments, at least 50%, or at least 55%, or at least 60%, or at least 65%, or at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95%, or at least 96%, or at least 97%, or at least 98%, or at least 99%, in particular 100% by number, of the particles of at least one crosslinked polymer material of said solid filler of the composite polymer layer are particles having a larger dimension between 50 pm and 100 pm.

[0035] According to certain embodiments, at least 50%, or at least 55%, or at least 60%, or at least 65%, or at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95%, or at least 96%, or at least 97%, or at least 98%, or at least 99%, in particular 100% by number, of the particles of at least one crosslinked polymer material of said solid filler of the composite polymer layer are particles having a larger dimension between 100 pm and 150 pm.

[0036] According to certain embodiments, at least 50%, or at least 55%, or at least 60%, or at least 65%, or at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95%, or at least 96%, or at least 97%, or at least 98%, or at least 99%, in particular 100% by number, of the particles of at least one crosslinked polymer material of said solid filler of the composite polymer layer are particles having a larger dimension between 150 pm and 200 pm.

[0037] According to certain embodiments, at least 50%, or at least 55%, or at least 60%, or at least 65%, or at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95%, or at least 96%, or at least 97%, or at least 98%, or at least 99%, in particular 100% by number, of the particles of at least one crosslinked polymer material of said solid filler of the composite polymer layer are particles having a larger dimension between 200 pm and 250 pm.

[0038] According to certain embodiments, at least 50%, or at least 55%, or at least 60%, or at least 65%, or at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95%, or at least 96%, or at least 97%, or at least 98%, or at least 99%, in particular 100% by number, of the particles of at least one crosslinked polymer material of said solid filler of the composite polymer layer are particles having a larger dimension between 250 pm and 300 pm.

[0039] According to certain embodiments, at least 50%, or at least 55%, or at least 60%, or at least 65%, or at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95%, or at least 96%, or at least 97%, or at least 98%, or at least 99%, in particular 100% by number, of the particles of at least one crosslinked polymer material of said solid filler of the composite polymer layer are particles having a larger dimension between 300 pm and 350 pm.

[0040] According to certain embodiments, at least 50%, or at least 55%, or at least 60%, or at least 65%, or at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95%, or at least 96%, or at least 97%, or at least 98%, or at least 99%, in particular 100% by number, of the particles of at least one crosslinked polymer material of said solid filler of the composite polymer layer are particles having a larger dimension between 350 pm and 400 pm.

[0041] According to certain embodiments, at least 50%, or at least 55%, or at least 60%, or at least 65%, or at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95%, or at least 96%, or at least 97% or at least 98% or at least 99%, including 100% by number, of the particles of at least one crosslinked polymer material of said solid filler of the composite polymer layer are particles having a larger dimension between 400 pm and 450 pm.

[0042] According to certain embodiments, at least 50%, or at least 55%, or at least 60%, or at least 65%, or at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95%, or at least 96%, or at least 97%, or at least 98%, or at least 99%, in particular 100% by number, of the particles of at least one crosslinked polymer material of said solid filler of the composite polymer layer are particles having a larger dimension between 450 pm and 500 pm.

[0043] According to certain embodiments, at least 50%, or at least 55%, or at least 60%, or at least 65%, or at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95%, or at least 96%, or at least 97%, or at least 98%, or at least 99%, in particular 100% by number, of the particles of at least one crosslinked polymer material of said solid filler of the composite polymer layer are particles having a larger dimension between 50 pm and 400 pm.

[0044] According to certain embodiments, at least 50%, or at least 55%, or at least 60%, or at least 65%, or at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95%, or at least 96%, or at least 97%, or at least 98%, or at least 99%, in particular 100% by number, of the particles of at least one crosslinked polymer material of said solid filler of the composite polymer layer are particles having a larger dimension between 100 pm and 300 pm.

[0045] According to certain embodiments, the particles of the solid filler based on crosslinked polymer material are particles having a relatively isotropic morphology. In this context, the particles of the solid filler based on crosslinked polymer material may, for example, have, along three directions orthogonal to each other (two by two), dimensions such that any ratio of two dimensions along two orthogonal directions is between 10:1 and 10:1, and more advantageously between 1:5 and 5:1, in particular between 1:4 and 4:1, for example between 1:3 and 3:1, or even between 1:2 and 2:1.

[0046] According to some embodiments, the particles of the solid filler based on crosslinked polymer material are all particles having a substantially isotropic morphology of this type.

[0047] According to certain embodiments, the solid particles of cross-linked polymer acting as solid filler in the cable of the invention do not comprise lamellar particles, the lamellar particles having: - two principal dimensions, called orthogonal dimensions, extending along two principal directions orthogonal to each other and orthogonal to a third direction of the particles, - a smaller dimension, specifically a thickness, transversely extending along the third direction of the particles, each of these orthogonal dimensions being greater than the said third dimension (or thickness), and, - two ratios, called form factors, between each of the two orthogonal dimensions and said third dimension (or thickness), at least one of said form factors being greater than 10.

[0048] According to certain embodiments, the solid particles of crosslinked polymer serving as solid filler in the cable of the invention are based on at least one crosslinked polymer material, advantageously recycled, which is preferably chosen from the group consisting of: - cross-linked polyethylene (XLPE), - crosslinked ethylene-propylene and ethylene-propene copolymers (“Ethylene Propylene Rubber”, EPR), in particular peroxide-crosslinked ethylene-propene copolymers, - chlorinated polyethylene (CPE) cross-linked, -crosslinked silicones, - crosslinked ethylene-vinyl acetate (EVA, "Ethylene-Virryl Acetate") copolymers, - crosslinked ethylene-vinyl copolymers (EVM, Ethylene-Vinyl Monomer), - crosslinked butadiene and acrylonitrile copolymers (NBR, "Nitrile Butadiene Rubber"), - crosslinked ethylene, propene and diene terpolymers (Ethylene-Propylene-Diene Monomer, EPDM), in particular ethylene, propene and diene terpolymers (Ethylene-Propylene-Diene Monomer, EPDM) crosslinked with peroxide or sulfur, - crosslinked mixtures of these polymers, in all proportions.

[0049] According to some embodiments, said at least one crosslinked polymer material is a crosslinked polyethylene (XLPE) or an ethylene, propene and diene terpolymer (Ethylene-Propylene-Diene Monomer, EPDM) which can, for example, be crosslinked by a peroxide.

[0050] According to some embodiments, the crosslinked polymer material of the solid filler is crosslinked by a crosslinking agent such as a peroxide, for example dicumyl peroxide, di-tert-butyl peroxide, cumene hydroperoxide or 1,3-bis(tert-buty Iperoxy isopropyl)benzene.

[0051] In certain embodiments, said at least one crosslinked polymer material is a polymer material crosslinked by a chemical crosslinking agent, such as sulfur, a peroxide, or a silane, or by radiation. In certain embodiments, at least one crosslinked polymer material is an olefinic copolymer or terpolymer comprising at least one copolymerizing monomer bearing a crosslinking group.

[0052] According to certain embodiments, the composite polymer layer of the electrical cable according to the invention is formed by applying—in particular by extrusion—a composite polymer composition comprising a quantity of said solid particles chosen such that said solid particles are present in the composite polymer composition with a mass proportion of between 1% and 50%. Mass proportion means the ratio, expressed as a percentage, of the mass of said solid filler to the mass of the composite polymer composition.

[0053] According to some of these preferred embodiments, the composite polymer layer is formed by applying a composite polymer composition comprising an amount of said solid filler chosen so that said solid filler is present in the composite polymer composition with a mass proportion between 1% and 25%.

[0054] According to some of these preferred embodiments, the composite polymer layer is formed by applying a composite polymer composition comprising an amount of said solid filler chosen so that said solid filler is present in the composite polymer composition with a mass proportion between 1% and 5%, in particular 1%, 2%, 3%, 4% or 5%.

[0055] According to some of these preferred embodiments, the composite polymer layer is formed by applying a composite polymer composition comprising an amount of said solid filler chosen so that said solid filler is present in the composite polymer composition with a mass proportion between 5% and 10%, in particular 5%, 6%, 7%, 8%, 9% or 10%.

[0056] According to some of these preferred embodiments, the composite polymer layer is formed by applying a composite polymer composition comprising an amount of said solid filler chosen so that said solid filler is present in the composite polymer composition with a mass proportion between 10% and 15%, in particular 10%, 11%, 12%, 13%, 14% or 15%.

[0057] According to some of these preferred embodiments, the composite polymer layer is formed by applying a composite polymer composition comprising an amount of said solid filler chosen so that said solid filler is present in the composite polymer composition with a mass proportion between 15% and 20%, in particular 15%, 16%, 17%, 18%, 19% or 20%.

[0058] According to some of these preferred embodiments, the composite polymer layer is formed by applying a composite polymer composition comprising an amount of said solid filler chosen so that said solid filler is present in the composite polymer composition with a mass proportion between 20% and 25%, in particular 20%, 21%, 22%, 23%, 24% or 25%.

[0059] According to some of these preferred embodiments, the composite polymer layer is formed by applying a composite polymer composition comprising an amount of said solid filler chosen so that said solid filler is present in the composite polymer composition with a mass proportion between 25% and 30%, in particular 25%, 26%, 27%, 28%, 29% or 30%.

[0060] According to some of these preferred embodiments, the composite polymer layer is formed by applying a composite polymer composition comprising an amount of said solid filler chosen so that said solid filler is present in the composite polymer composition with a mass proportion between 30% and 35%, in particular 30%, 31%, 32%, 33%, 34% or 35%.

[0061] According to some of these preferred embodiments, the composite polymer layer is formed by applying a composite polymer composition comprising an amount of said solid filler chosen so that said solid filler is present in the composite polymer composition with a mass proportion between 35% and 40%, in particular 35%, 36%, 37%, 38%, 39% or 40%.

[0062] According to some of these preferred embodiments, the composite polymer layer is formed by applying a composite polymer composition comprising an amount of said solid filler chosen so that said solid filler is present in the composite polymer composition with a mass proportion between 40% and 45%, in particular 40%, 41%, 42%, 43%, 44% or 45%.

[0063] According to some of these preferred embodiments, the composite polymer layer is formed by applying a composite polymer composition comprising an amount of said solid filler chosen so that said solid filler is present in the composite polymer composition with a mass proportion between 45% and 50%, in particular 45%, 46%, 47%, 48%, 49% or 50%.

[0064] According to some of these embodiments, the composite polymer layer is formed by applying a composite polymer composition comprising a quantity of said solid filler chosen so that said solid filler is present in the composite polymer composition with a mass proportion greater than 50%.

[0065] According to certain embodiments, the composite polymer layer is an electrically insulating composite polymer layer. The term "electrically insulating composite polymer layer" or "electrically insulating layer" means a composite polymer layer whose electrical conductivity can be at most 1.108 S / m (siemens per meter), in particular at most 1.109 S / m (siemens per meter), preferably at most 1.10 10 S / m (siemens per meter), more preferably at most 1.10 12 S / m (siemens per meter), measured at 25 °C in direct current.

[0066] According to certain embodiments, the polymer matrix of the composite polymer layer is a thermoplastic electrically insulating polymer matrix. The polymer material forming the thermoplastic electrically insulating polymer matrix of the composite polymer layer may be a homopolymer, a copolymer, or a terpolymer exhibiting thermoplastic properties. Such a polymer material may be selected from the group consisting of polyolefins, polyurethanes, polyamides, polyesters, polyvinyls, or halogenated polymers such as fluoropolymers (e.g., polytetrafluoroethylene, PTFE) or chlorinated polymers (e.g., polyvinyl chloride, PVC). Such a polyolefin may be selected from ethylene polymers and propylene polymers.Examples of ethylene polymers include linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE).

[0067] Such a polyolefin can be selected from ethylene and vinyl acetate (EVA) copolymers, ethylene and butyl acrylate (EBA) copolymers, ethylene and methyl acrylate (EMA) copolymers, ethylene and 2-hexylethyl acrylate (2HEA) copolymers, ethylene and alpha-olefin copolymers such as, for example, polyethylene-octene (PEO), ethylene and propylene (EPR) copolymers, ethylene / ethyl acrylate (EEA) copolymers, or ethylene and propylene (EPT) terpolymers such as, for example, ethylene-propylene-diene monomer (EPDM) terpolymers.

[0068] According to certain embodiments, the polymer matrix of the composite polymer layer is a crosslinked electrically insulating polymer matrix. The polymer material forming the crosslinked electrically insulating polymer matrix of the composite polymer layer may be a crosslinked polyolefin. It may be a crosslinked ethylene homopolymer such as, for example, crosslinked high-density polyethylene (HDPE), crosslinked medium-density polyethylene (MDPE), a cross-linked low-density polyethylene (LDPE), cross-linked linear low-density polyethylene (LLDPE) or cross-linked very low-density polyethylene (VLDPE) or a mixture of such polymers.

[0069] This may be a crosslinked copolymer of ethylene and at least one short-chain α-olefin, such as, for example, propene, but-l-ene, hex-l-ene and / or oct-1-ene. It may be a copolymer of ethylene and an α-olefin such as an ethylene-octene copolymer (PEO) or an ethylene-butene copolymer (PEB). It may be a crosslinked LLDPE (Linear Low-Density Polyethylene) copolymer. It may be an ethylene-propylene elastomer (EPR), an ethylene-propylene-diene monomer terpolymer (EPDM), an ethylene-vinyl ester copolymer, an ethylene-vinyl acetate (EVA) copolymer, an ethylene-butyl acetate (EBA) copolymer, or an ethylene-ethyl acetate (EEA) copolymer. It may also be an ethylene-acrylate copolymer such as an ethylene-butyl acrylate (EBA) copolymer or an ethylene-methyl acrylate (EMA) copolymer.It may be a functionalized olefin polymer, polypropylene, a propylene copolymer and any mixture of these polymers, homopolymers, copolymer and / or terpolymers.

[0070] According to some embodiments, the polymer material forming the crosslinked electrically insulating polymer matrix of the composite polymer layer is crosslinked by a crosslinking agent such as a peroxide, for example dicumyl peroxide, di-tert-butyl peroxide, cumene hydroperoxide or 1,3-bis(tert-butylperoxyisopropyl)benzene.

[0071] According to certain embodiments, the composite polymer layer is a semiconducting composite polymer layer. The term "semiconducting composite polymer layer" or "semiconducting layer" means a layer whose electrical conductivity may be strictly greater than 1.108 S / m (Siemens per meter), preferably of at least 1.103 S / m, and preferably may be less than 1.103 S / m, measured at 25°C in direct current.

[0072] In these embodiments, the semiconducting composite polymer layer includes a conductivity-enhancing additive such as carbon black, carbon nanotubes, graphene or a mixture thereof.

[0073] According to certain embodiments, the polymer matrix of the composite polymer layer is a thermoplastic semiconducting polymer matrix. The polymer material forming the thermoplastic semiconducting polymer matrix of the composite polymer layer may be a homopolymer, a copolymer, or a terpolymer exhibiting thermoplastic properties. Such a polymer material may be selected from the group consisting of polyolefins, polyurethanes, polyamides, polyesters, polyvinyls, or halogenated polymers such as fluoropolymers. (e.g., polytetrafluoroethylene, PTFE) or chlorinated polymers (e.g., polyvinyl chloride, PVC). Such a polyolefin can be chosen from ethylene polymers and propylene polymers. Examples of ethylene polymers include linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE).

[0074] Such a polyolefin can be selected from ethylene and vinyl acetate (EVA) copolymers, ethylene and butyl acrylate (EBA) copolymers, ethylene and methyl acrylate (EMA) copolymers, ethylene and 2-hexylethyl acrylate (2HEA) copolymers, ethylene and alpha-olefin copolymers such as, for example, polyethylene-octene (PEO), ethylene and propylene (EPR) copolymers, ethylene / ethyl acrylate (EEA) copolymers, or ethylene and propylene (EPT) terpolymers such as, for example, ethylene-propylene-diene monomer (EPDM) terpolymers.

[0075] According to certain embodiments, the polymer matrix of the composite polymer layer is a crosslinked semiconducting polymer matrix. The polymer material forming the crosslinked semiconducting polymer matrix of the composite polymer layer may be a crosslinked polyolefin. It may be a crosslinked ethylene homopolymer such as, for example, crosslinked high-density polyethylene (HDPE), crosslinked medium-density polyethylene (MDPE), crosslinked low-density polyethylene (LDPE), crosslinked linear low-density polyethylene (LLDPE), or crosslinked very low-density polyethylene (VLDPE), or a mixture of such polymers.

[0076] It may be a crosslinked copolymer of ethylene and at least one short-chain α-olefin, such as, for example, propene, but-l-ene, hex-l-ene and / or oct-1-ene. It may be a copolymer of ethylene and an α-olefin such as an ethylene-octene copolymer (PEO) or an ethylene-butene copolymer (PEB). It may be a crosslinked LLDPE (Linear Low-Density Polyethylene) copolymer. It may be an ethylene-propylene elastomer (EPR), an ethylene-propylene-diene monomer terpolymer (EPDM), an ethylene-vinyl ester copolymer, an ethylene-vinyl acetate (EVA) copolymer, an ethylene-butyl acetate (EBA) copolymer, or an ethylene-ethyl acetate (EEA) copolymer. It may also be an ethylene-acrylate copolymer such as an ethylene-butyl acrylate (EBA) copolymer or an ethylene-methyl acrylate (EMA) copolymer.It may be a functionalized olefin polymer, polypropylene, a propylene copolymer and any mixture of these polymers, homopolymers, copolymer and / or terpolymers.

[0077] According to these embodiments, the polymer material forming the crosslinked semiconducting polymer matrix of the composite polymer layer is crosslinked by a crosslinking agent such as a peroxide, for example dicumyl peroxide, di-tert-butyl peroxide, cumene hydroperoxide or 1,3-bis(tert-butylperoxyisopropyl)benzene.

[0078] In certain embodiments, the micronized particles of said solid feed are particles micronized by grinding and / or micronization—in particular, cold micronization—of waste comprising at least one cross-linked polymer material. In certain embodiments, the micronization is shear micronization—for example, carried out using a disc micronizer, a pin micronizer, or a knife micronizer—impact micronization, for example, carried out in a hammer micronizer, or air jet micronization. Such grinding and / or micronization of waste comprising at least one cross-linked polymer material is adapted to form a powder of micronized particles suitable for incorporation into, in particular to constitute, said solid feed.

[0079] In some embodiments, the micronized particles of said solid feedstock are particles micronized by grinding and / or micronizing a recycled crosslinked polymer material previously cooled to a temperature below its glass transition temperature. In some embodiments, the recycled crosslinked polymer material is previously cooled in liquid nitrogen.

[0080] According to certain embodiments, the composite polymer layer is a low-voltage insulating composite polymer layer in which the polymer matrix is ​​a peroxide-crosslinked ethylene-propylene-diene monomer (EPDM) terpolymer base and in which said solid filler comprises mineral particles, in particular chalk (CaCO3) particles with an average diameter of approximately 1 µm. According to these embodiments, particles of at least one crosslinked polymer material, advantageously recycled, in particular crosslinked polyethylene (XLPE) particles, are present in a mass proportion of approximately 10% in the insulating composite polymer layer.

[0081] According to certain embodiments, the composite polymer layer is a low-voltage insulating composite polymer layer in which the polymer matrix is ​​a linear low-density polyethylene (LLDPE) base crosslinked with a silane and in which said solid filler comprises crosslinked polyethylene (XLPE) particles, the crosslinked polyethylene (XLPE) particles being in a mass proportion of between 2.5% and 50% in the insulating composite polymer layer. According to these embodiments, the crosslinked polyethylene (XLPE) particles are in a mass proportion of approximately 2.5%, or approximately 5%, or approximately 7.5%, or approximately 10%, or approximately 25%, or approximately 50%, in the insulating composite polymer layer.

[0082] According to another aspect, the present invention relates to an electrical device equipped with an insulating system according to the invention, which is an accessory for an electrical cable.

[0083] Such an accessory according to the invention comprises an insulating system that includes at least one insulating layer comprising a polymer matrix in which solid particles of cross-linked polymer are dispersed. These solid particles act as solid fillers in the insulating system of the accessory and are preferably such as those described for a cable according to the invention. Thus, they advantageously consist of particles of at least one cross-linked polymer material, advantageously recycled. Furthermore, the particles advantageously have a median size d50 by mass and / or a median size d50 by volume of between 10 and 1000 µm, in particular between 50 and 500 µm, for example between 100 and 500 µm.

[0084] According to some embodiments, the particles of at least one crosslinked polymer material of said solid filler are micronized particles.

[0085] According to some embodiments, the accessory for electrical cable is a junction or termination for electrical cable.

[0086] The invention also extends to a method of manufacturing a device (cable or cable accessory) according to the invention, comprising the insulating system including an insulating layer of the invention, this method comprising: a step of applying a layer of an insulating system, this step including an incorporation of solid particles of crosslinked polymer into a polymer matrix and the application of the composite polymer composition obtained in particular by extrusion where the solid particles of crosslinked polymer were preferably obtained in a prior step of grinding and / or micronizing a waste comprising at least one crosslinked polymer material.

[0087] It should be noted that the insulating system of the invention comprises, among other possible constituents, solid particles of cross-linked polymer within the polymer matrix. The insulating system may, of course, include other additives in the polymer matrix in addition to the solid particles of cross-linked polymer, for example, mineral fillers, plasticizers, or stabilizers. Additives other than solid particles of cross-linked polymer may be added to the polymer matrix: - in whole or in part before the solid particles of cross-linked polymer; and / or - in whole or in part after the solid particles of cross-linked polymer; and / or - in whole or in part simultaneously with all or part of the solid particles of cross-linked polymer.

[0088] In other words, some additives can be pre- or post-added and others added in a mixture with solid particles of crosslinked polymer, and, according to some conceivable modes, the solid particles of crosslinked polymer can be added in several stages, with or without pre-, post- or co-addition of additives.

[0089] Optionally, the electrical device is an electrical cable comprising a conductive core and an insulating system surrounding said conductive core, and in which the insulating system comprises at least one layer comprising a polymer matrix in which solid particles of cross-linked polymer are dispersed.

[0090] Optionally, in this electrical cable, the solid particles of crosslinked polymer are obtained from grinding and / or micronizing waste or scrap based on one or more crosslinked polymers.

[0091] Optionally, in this electrical cable, the solid particles of crosslinked polymer have a median size d50 in mass and / or volume between 10 pm and 1000 pm, for example between 50 and 500 pm.

[0092] Optionally, in this electrical cable, the solid particles of crosslinked polymer are based on at least one crosslinked polymer material selected from the group consisting of: - cross-linked polyethylene (XLPE), - crosslinked ethylene-propylene and ethylene-propene (EPR) copolymers, in particular peroxide-crosslinked ethylene-propene copolymers, - crosslinked chlorinated polyethylene (CPE), - crosslinked silicones, - crosslinked ethylene and vinyl acetate (EVA) copolymers, - crosslinked ethylene vinyl copolymers (EVM), - crosslinked butadiene and acrylonitrile (NBR) copolymers, - crosslinked ethylene, propene and diene terpolymers (EPDM), and - their mixtures in all proportions.

[0093] Optionally, in this electrical cable, the layer including the solid particles of crosslinked polymer of the electrical cable is formed by applying a composite polymer composition comprising an amount of said solid particles chosen so that said solid particles are present in the composite polymer composition with a mass proportion between 1% and 50%.

[0094] Optionally, in this electrical cable, the layer is an electrically insulating layer.

[0095] Optionally, in this electrical cable, the layer is a semiconducting layer.

[0096] Optionally, in this electrical cable, the polymer matrix of the layer is a thermoplastic polymer matrix.

[0097] Optionally, in this electrical cable, the polymer matrix of the layer is a cross-linked polymer matrix.

[0098] The invention also relates to a method for manufacturing a device such as the one mentioned above, this method comprising: a step of applying a layer of an insulating system, this step including an incorporation of solid particles of crosslinked polymer into a polymer matrix and the application of the resulting composite polymer composition, for example in particular by extrusion.

[0099] Optionally, the solid particles of crosslinked polymer are obtained in a prior step of grinding and / or micronizing waste comprising at least one crosslinked polymer material.

[0100] Other features and advantages of the present invention will become apparent from the description of the non-limiting examples of an electrical cable according to the invention, an accessory for an electrical cable according to the invention, and a manufacturing method according to the invention with reference to the single figure.

[0101] [Fig-1] Fig. 1 is an illustrative flowchart of a manufacturing process for a electrical cable according to the invention.

[0102] A method according to the invention is a method for manufacturing an electrical cable 10 comprising a conductive core 7 and an insulating system 9 extending coaxially around the conductive core 7, the insulating system 9 comprising at least one composite polymer layer 8 comprising a polymer matrix 11 and a filler, called solid filler 3, dispersed in the volume of the polymer matrix 11.

[0103] In a process according to the invention, waste 1 comprising at least one cross-linked polymer material that is neither recoverable nor recyclable in a conventional thermomechanical process is collected. This may involve the collection of an end-of-life electrical cable insulation system, or the collection of production waste or extruder purge waste. The waste is collected by any means known to those skilled in the art. In the case of an end-of-life electrical cable or accessory, the electrical cable and / or accessory is / are subjected to a preliminary separation and sorting step of its main constituents, during which the metals constituting the conductive core, a metallic screen, and / or a metallic reinforcement are separated from the non-metallic materials.The collected and sorted waste is then subjected to a second step of progressive grinding of the collected waste (step 1), supplemented by at least one micronization step adapted to form a powder of globular particles with a median size between 100 µm and 1000 µm. The second micronization step can be carried out by any known means, such as, for example, a disc micronizer for shear micronization, a hammer micronizer for impact micronization, or an air jet micronizer. In some embodiments, at least one second step of grinding and successive micronization is carried out at room temperature, for example, in liquid nitrogen. A solid feed (step 3) in the form of a powder is obtained.

[0104] The process according to the invention comprises a step 4 of dispersing the solid filler 3 in a polymer matrix 11. This dispersion step 4 can advantageously be carried out under heat using a single-screw or twin-screw extruder or a mixer so as to form a composite polymer composition 5 in which said solid filler 3 is distributed substantially homogeneously in the polymer matrix 11. This dispersion step 4 is carried out so as to form an extrudable composite polymer composition 5.

[0105] In a subsequent extrusion step 6, the composite polymer composition 5 is extruded or co-extruded around a conductive core 7 formed of one or more elongated conductive metallic elements, for example, aluminum or copper, so as to form a composite polymer layer 8. The composite polymer layer 8 may be extruded in contact with the conductive core 7 or in contact with a layer interposed between the conductive core 7 and the composite polymer layer 8. An insulating system 9 is thus formed by extrusion, comprising said composite polymer layer 8 surrounding the conductive core 7 and the electrical cable 10. There is nothing to prevent the dispersion step 4 of the solid filler 3 in the polymer matrix 11 from being carried out during the extrusion step 6 by adding said micronized solid filler using a dosing device for said solid filler.

[0106] In a particular embodiment, not shown but legible in [Fig. 1], a method for manufacturing an accessory for an electrical cable comprises the successive steps 2 of grinding and micronizing a waste material 1, step 4 of dispersing the solid filler 3 in a polymer matrix 11 and forming the composite polymer composition 5, this dispersion being able to be carried out in one or more steps, with or without pre-, co-, or post-addition of additives other than the solid filler 3. In this unshown embodiment, the composite polymer composition 5 can be used to manufacture an accessory for an electrical cable. EXAMPLES

[0107] EXAMPLE 1 - INCORPORATION OF MICRONIZED XLPE IN AN XLPE INSULATOR

[0108] Micronized XLPE

[0109] Micronized XLPE (mXLPE) is a powder obtained by shearing XLPE in a disc micronizer. The median particle diameter d50 of the micronized XLPE powder, determined by the vibrating sieve method, is between 400 µm and 500 µm. d90 is 500 µm and d99 is less than 630 µm.

[0110] Incorporation of micronized XLPE particles into a low-voltage insulation mixture

[0111] Micronized XLPE particles are incorporated into a low-voltage insulation composition consisting of: - of LLDPE with a melt flow index of 3.3g / 10min, 190°C, 2.16 Kg supplemented by a stabilizing mixture of dye and antioxidant, - of a crosslinking composition based on vinyltrimethoxysilane (VTMO) formulated, by substitution of a mass fraction of LLDPE supplemented by the same mass of micronized XLPE particles (compositions (B) to composition (G) according to Table 1 below). [Tables 1] Low voltage insulation composition ABCDEFG Complemented LLDPE, % by mass 100 97.5 95 92.5 90 75 50 Micronized XLPE, % by mass 0 2.5 5 7.5 10 25 50 Table 1

[0112] The reference insulation composition (A), free from micronized XLPE particles, is composed of: - 98.8% by mass of an LLDPE blend comprising 0.6% by mass of stabilizing masterbatch, and - 1.2% by mass of said crosslinking composition.

[0113] Implementation: Low levels of micronized XLPE (mXLPE), compositions (B) to (D)

[0114] Step 1:

[0115] A masterbatch (MM mXLPE 25%) comprising a mass proportion of 75% of complemented LLDPE (composition (A)) and a mass proportion of 25% of micronized XLPE is first produced in a twin-screw extruder according to the following temperature profile 140 / 150 / 160 / 170 / 170 / 180 / 180 / 190 / 200 / 200°C, the screw rotation speed being 100 rpm and the extruder outlet flow rate being 10 Kg / h.

[0116] Step 2 The masterbatch (MM mXLPE 25%) obtained at the twin-screw extruder outlet at the stage 1 is diluted in LLDPE supplemented with the colorant and antioxidant stabilizing mixture (0.6% by mass) to achieve the stated mass proportions of mXLPE and supplemented LLDPE mixture, ranging from 2.5% to 7.5%. The dilution is carried out in a twin-screw extruder according to the following temperature profile: 140 / 150 / 160 / 170 / 170 / 180 / 180 / 190 / 200 / 200°C, with a screw rotation speed of 100 rpm and an extruder outlet flow rate of 10 kg / h of the diluted mixture.

[0117] Step 3 Each diluted mixture obtained at the outlet of the twin-screw extruder in step 2 is brought into contact and maintained in contact for impregnation with said crosslinking composition. in mass proportion of 1.2% relative to the mixture diluted for 12 hours at room temperature.

[0118] Step 4 Strips with a thickness of 1 mm are extruded in a single screw extruder according to the following temperature profile 25 / 110 / 160 / 180 / 190 / 200 / 210 / 210°C, barrier screw, the screw rotation speed being 25 rpm.

[0119] Step 5 The resulting strips were subjected to forced crosslinking in water heated to a temperature of 63°C for a period of 24 hours.

[0120] Implementation: High levels of micronized XLPE (mXLPE), compositions (E) to (G)

[0121] Step 1 Compositions (E), (F), and (G) are made by mixing supplemented LLDPE (composition (A)) with a stabilizing mixture of dye and antioxidant (0.6% by mass) and micronized XLPE in quantities chosen to achieve the stated mass proportions of micronized XLPE and supplemented LLDPE, ranging from 10% to 50%. The mixing is carried out in a twin-screw extruder according to the following temperature profile: 140 / 150 / 160 / 170 / 170 / 180 / 180 / 190 / 200 / 200°C, with a screw rotation speed of 100 rpm and a flow rate of 10 kg / h of the diluted mixture at the extruder outlet. Similar results can be obtained according to the following extrusion temperature profile: 140 / 150 / 160 / 170 / 170 / 180 / 180 / 190 / 200 / 200°C.

[0122] Step 2 Each diluted mixture obtained at the outlet of the twin-screw extruder in step 2 is brought into contact and kept in contact for impregnation with said crosslinking composition in mass proportion of 1.2% relative to the diluted mixture for 12 hours at room temperature.

[0123] Step 3 Strips with a thickness of 1 mm are extruded in a single screw extruder according to the following temperature profile 25 / 110 / 160 / 180 / 190 / 200 / 210 / 210°C, barrier screw and screw rotation speed being 25 rpm.

[0124] Step 4 The resulting strips were subjected to forced crosslinking in water heated to a temperature of 63°C for a period of 24 hours.

[0125] Characterization of the Properties of the Composite Materials Obtained - Results The properties of the composite materials obtained were analyzed and compared with the specifications of a low-voltage XLPE insulator. The results are given in Table 2 below. [Tables 2] Properties ABCDEFG HST under load, % 35% 40% 35% 40% 35% 40% 35% HST without load, % 0% 0% 0% 0% 0% 0% 0% TSP, MPa 33.4 ± 23.2 ± 22.9 23.0 19.4 16.4 12.4 1.7 2.5 ±0.6 ±1.5 ±1.2 ±0.7 ±0.9 EB, % 602 545 526 527 527 454 339 ±13 ±24 ±17 ±25 ±12 ±10 ±25 Aging 33.4 22.9 23.2 22.1 19.3 17.1 13.3 TSP, MPa ±1.2 ±2.9 ±1.8 ±0.7 ±2.0 ±1.1 ±1.1 Aging A TSP, MPa 0% -1% +1% -4% -1% +4% +7% Aging 562 511 506 485 487 448 327 EB, % ±11 ±37 ±18 ±10 ±34 ±25 ±35 Aging A EB, % -7% -6% -4% -8% -8% -1% -4% Density, g / cm3 0.91 0.91 0.91 0.91 0.91 0.91 0.91 Water content, mg / cm3 / / / / 0.02 0.02 0.03 MFI, g / 10 min 3.3 2.6 2.4 2.2 2.1 0.8 0 Table 2

[0126] The elongation under stress test (“Hot Set Test”, HST) is carried out at a temperature of 200°C under 0.2 MPa, as defined according to standard NF EN 60811-2-1;

[0127] The tensile strength peak test (“Tensile Strength Peak”, TSP) is carried out at a rate of 250 mm / min, as defined according to Standard NF EN 60811-1-1;

[0128] The elongation at break test (“Elongation at Break”, EB) is carried out at a rate of 250 mm / min, as defined according to Standard NF EN 60811-1-1;

[0129] The analysis of the mechanical properties after thermal aging is carried out at a rate of 250 mm / min after exposure for 168 hours at a temperature of 135°C;

[0130] Water absorption analysis is performed after exposure to 85°C for 335 hours;

[0131] The Melt Flow Index (MFI) before crosslinking is measured at a temperature of 190°C under a stress of 2.16 kg. For composition "G", the MFI is 0.5 g / min under a stress of 5 kg.

[0132] The hot elongation tests (HST) are compliant and unchanged from the specifications. The incorporation of mXLPE does not disrupt the crosslinking of the mixtures. Incorporating up to 50% by mass of mXLPE in the mixtures leads to a decrease in mechanical properties, which nevertheless remain compliant with the specifications. Resistance to thermal aging and water absorption are not affected. Finally, an increase in viscosity is observed upon the addition of mXLPE. This increase remains small up to levels of 10% by mass.

[0133] EXAMPLE 2

[0134] Incorporation of micronized XLPE into an EPDM insulation

[0135] Micronized XLPE Micronized XLPE (mXLPE) is a powder obtained by shearing XLPE in a disc micronizer. The median particle diameter d50 of the micronized XLPE powder, determined by the vibrating sieve method, is between 400 µm and 500 µm.

[0136] Incorporation of micronized XLPE particles into a low-voltage insulation mixture Micronized XLPE (mXLPE) particles are incorporated into a mixture formulated to form a low-voltage insulator based on peroxide-crosslinked ethylene-propylene-diene monomer (EPDM) and comprising a 60% mass content of chalk particles with an average diameter of 1 µm in the mixture. The formulated mixture further includes a plasticizer, stabilizers, and an inorganic filler.

[0137] Micronized XLPE (mXLPE) particles are incorporated into the formulated mixture comprising by mass: - 40% EPDM base blend, - 60% of chalk particle charge with an average diameter of 1 pm, by replacing a mass fraction of the chalk particle charge with the same mass of micronized XLPE particles (Table 3). [Tables 3] AB EPDM, % by mass 40 40 Chalk particles (D50: Ipm) 60 50 Micronized XLPE, % by mass 0 10 Table 3

[0138] Implementation Mixtures (A) and (B) are produced in three successive steps: Incorporation of the various raw materials, including mXLPE, in a mixer internal (18 min, discharge at 105 °C), then resumption of mixing on an external mixer (twin cylinders) at 105 °C, then cross-linking under pressure at 180 °C, for a duration equal to 2 times the optimal curing time plus 4 minutes, (duration 2*t90+4miiï)

[0139] Characterizations: The properties of the composite materials obtained were analyzed. The results are given in Table 4 below. [Tables 4] AB Crosslinking, ts2 (s) 63 80 Crosslinking, t90 (min) 7.41 10.0 Mooney viscosity, ML (MU) 32 48 Mechanical properties, TSP, MPa 7.2 6.5 Aging TSP, MPa 7.9 6.6 Aging, ATSP, % 10 2 Aging, AEB, % 5 3 Cold resistance, elongation, mg / cm2 277 148 Table 4

[0140] The hardening of the composite materials “A” and “B” is monitored for 30 minutes at a temperature of 180°C.

[0141] “ts2” (scorch time) corresponds to the time required to increase the viscosity of crosslinking of 0.2 Nm;

[0142] “t90” (curing time) corresponds to the time required to reach 90% of the final crosslinking;

[0143] The Mooney viscosity test is carried out at 100°C.

[0144] The tensile strength peak (TSP) test carried out at a rate of 250 mm / min, as defined according to Standard NF EN 60811-1-1

[0145] The analysis of mechanical properties (TSP, EB) after thermal aging is carried out at a rate of 250 mm / min after exposure for 168 hours at a temperature of 135°C.

[0146] Replacing a fraction corresponding to 10% by mass of chalk with a corresponding fraction of 10% by mass of micronized XLPE maintains properties that meet the expected specifications for the insulation. Thermal aging is not affected by this replacement.

[0147] The composite polymer layer conforms to the specifications for the insulating system of an electrical cable. The composite polymer layer of the electrical cable according to the invention makes it possible to convert end-of-life used electrical cable insulating systems and / or scrap, in particular production scrap or purging scrap from an extruder, constituting waste that is not recyclable by conventional thermomechanical extrusion and / or injection processes, into high value-added components suitable for use in a manufacturing process for electrical cables and / or electrical cable accessories and to enable the manufacture of electrical cables and / or accessories with satisfactory mechanical, insulating or semiconducting properties.The invention also enables the recycling of such waste and its recovery in applications aimed at the manufacture of electrical cables and / or accessories, and promotes a circular approach - in particular of cross-linked polymer waste which is not recyclable in conventional thermomechanical processes - and reduction of waste from the production of electrical cables.

Claims

Demands

1. Electrical device equipped with an insulating system, said device being an electrical cable or an accessory for an electrical cable, and wherein the insulating system of the device includes at least one layer comprising a polymer matrix in which solid particles of cross-linked polymer are dispersed.

2. Electrical device according to claim 1, which is an electrical cable (10) comprising a conductive core (7) and an insulating system (9) surrounding said conductive core (7), and in which the insulating system comprises at least one layer (8) comprising a polymer matrix (11) in which solid particles (3) of crosslinked polymer are dispersed.

3. An electrical device (10) according to claim 2, wherein the solid particles (3) of crosslinked polymer are obtained from grinding and / or micronizing waste or scrap based on one or more crosslinked polymers

4. Electrical device (10) according to claim 2 or 3, wherein the solid crosslinked polymer particles (3) have a median size d50 in mass and / or volume between 10 pm and 1000 pm, for example between 50 and 500 pm.

5. An electrical device (10) according to any one of claims 2 to 4, wherein the solid crosslinked polymer particles (3) are based on at least one crosslinked polymer material selected from the group consisting of: - crosslinked polyethylenes (XLPE), - crosslinked ethylene-propylene, ethylene-propene (EPR) copolymers, in particular peroxide-crosslinked ethylene-propene copolymers, - crosslinked chlorinated polyethylenes (CPE), - crosslinked silicones, - crosslinked ethylene-vinyl acetate (EVA) copolymers, - crosslinked ethylene-vinyl (EVM) copolymers, - crosslinked butadiene-acrylonitrile (NBR) copolymers, - crosslinked ethylene-propene-diene terpolymers (EPDM), and - mixtures thereof. proportions.

6. Electrical device (10) according to any one of claims 2 to 5, wherein the layer (8) includes the solid particles of crosslinked polymer of the

7.

8.

9.

10.

11.

12.

13. electrical cable (10) is formed by applying a composite polymer composition comprising a quantity of said solid particles (3) chosen so that said solid particles (3) are present in the composite polymer composition (8) with a mass proportion between 1% and 50%. Electrical device (10) according to any one of claims 2 to 6, wherein the layer (8) is an electrically insulating layer. Electrical device (10) according to any one of claims 2 to 6, wherein the layer (8) is a semiconducting layer. Electrical device (10) according to claim 7 or 8, wherein the polymer matrix of layer (8) is a thermoplastic polymer matrix. Electrical device (10) according to claim 7 or 8, wherein the polymer matrix of layer (8) is a cross-linked polymer matrix. Electrical device (10) according to claim 1, the electrical device being a junction or termination for an electrical cable. A method for manufacturing a device according to claim 1, said method comprising: a step of applying a layer of an insulating system, this step including an incorporation of solid particles of crosslinked polymer into a polymer matrix and the application of the resulting composite polymer composition, for example in particular by extrusion. Process according to claim 12, wherein the solid particles of crosslinked polymer are obtained in a prior step of grinding and / or micronizing waste comprising at least one crosslinked polymer material.