Multilayer structure for transporting or storing hydrogen

Abstract

The present invention provides a multilayer structure configured for transporting, distributing, or storing hydrogen. [Solution] The multilayer structure comprises at least one sealing layer and at least one composite reinforcing layer from the inside out, with the innermost composite reinforcing layer welded to the outermost adjacent sealing layer. The sealing layer is made of a composition mainly comprising at least one semicrystalline polyamide thermoplastic polymer, an impact modifier, and a plasticizer, and the at least one polyamide thermoplastic polymer in each sealing layer may be the same or different, and at least one of the composite reinforcing layers is made of a fibrous material in the form of continuous fibers impregnated with a composition mainly comprising at least one semicrystalline polyamide polymer, and the number of carbon atoms per amide functional group of the polyamide in the outermost adjacent sealing layer differs by up to 20% from the number of carbon atoms per amide functional group of the polyamide in the innermost reinforcing layer.

Description

Technical Field

[0001] The present patent application relates to a multilayer composite structure for transporting, distributing or storing hydrogen, in particular for distributing or storing hydrogen, and to a method for producing said structure.

Background Art

[0002] Hydrogen tanks currently attract a great deal of attention from numerous manufacturers, especially in the automotive sector. One of the goals being pursued is to propose additional low-emission vehicles. Accordingly, it is aimed to gradually replace vehicles with internal combustion engines, such as gasoline or diesel vehicles, with electric or hybrid vehicles including batteries. Batteries have been found to be relatively complex vehicle components. Depending on the positioning of the battery in the vehicle, it may be necessary to protect the battery from impacts and from the external environment, which can have extremely high temperatures and variable humidity. It may also be necessary to avoid any risk of fire.

[0003] Furthermore, it is important that their operating temperature does not exceed 55°C, in order not to damage the battery cells and to prolong their service life. Conversely, for example in winter, it may be necessary to increase the temperature of the battery to optimize its operation.

[0004] Furthermore, electric vehicles still suffer from several problems today: battery range, the use of rare earth metals in these batteries, non-renewable resources, charging times that are much longer than the time required for tank refueling, as well as the problem of electricity generation to enable battery charging in various countries.

[0005] Therefore, hydrogen is a substitute for electric batteries, since hydrogen can be converted into electricity by fuel cells, thereby powering electric vehicles.

[0006] Hydrogen tanks typically consist of a metal liner (or sealing layer) that must protect hydrogen from permeation. One type of tank that is conceivable is called Type IV, which is based on a thermoplastic liner with a composite wrapped around it.

[0007] The fundamental principle is to separate the two essential functions of sealing and mechanical strength and manage them independently of each other. In this type of tank, the liner (or sealing sheath) made of thermoplastic resin is combined with a reinforcing structure consisting of fibers (glass, aramid, carbon) wrapped in a thermoplastic or thermosetting matrix, also known as a reinforcing sheath or layer, which allows it to operate at much higher pressures while reducing weight and avoiding the risk of explosion in the event of severe external impact.

[0008] Liner has a certain principle characteristic: Potential conversion methods include extrusion blow molding, rotational molding, injection molding, or extrusion. Low hydrogen permeability, or in fact, the permeability of the liner, is a crucial factor in limiting hydrogen leakage from the tank. Good mechanical properties (fatigue) at low temperatures (-40 to -70°C), It must be heat resistant up to 120°C.

[0009] In practice, it is necessary to increase the filling rate of the hydrogen tank, which should be roughly equivalent to that of a fuel tank for an internal combustion engine (about 3 to 5 minutes). However, this increase in rate causes the tank to heat up more significantly, then reaching a temperature of about 100°C.

[0010] The first generation Type IV tanks used a high-density polyethylene (HDPE) based liner.

[0011] However, HDPE has the disadvantage of having too low a melting point and too high a hydrogen permeability, which presents a problem in terms of heat resistance, preventing an increase in tank filling speed.

[0012] Polyamide PA6-based liners have been under development for many years.

[0013] Nevertheless, PA6 has the disadvantage of having low resistance to cold.

[0014] WO18155491 describes a hydrogen transport component having a three-layer structure, the inner layer comprising PA11, 15 to 50% impact modifier, and 1 to 3% plasticizer, or a composition lacking plasticizer, the composition having hydrogen barrier properties, good flexibility at low temperatures, and durability. However, this structure is suitable for pipes for transporting hydrogen, but not for storing hydrogen.

[0015] Therefore, on the one hand, it is necessary to optimize the matrix of the composite so as to optimize the mechanical strength of the composite matrix at high temperatures, and on the other hand, it is still necessary to optimize the materials including the sealing sheath so as to optimize the operating temperature of the sealing sheath. Thus, any change in the choice of materials of the composition including the sealing liner that is carried out should not cause a significant increase in the manufacturing temperature of this liner (extrusion blow molding, injection molding, rotational molding, etc.) compared to those practiced today. [Overview of the Initiative]

[0016] These problems are solved by providing the multilayer structure of the present invention configured for transporting, distributing, or storing hydrogen.

[0017] Throughout this specification, the terms “liner” and “sealing sheath” have the same meaning.

[0018] The present invention relates to a multilayer structure configured, in particular for storage, for transporting, distributing, and storing hydrogen, It includes at least one sealing layer (1) and at least one composite reinforcing layer (2) from the inside out, The innermost composite reinforcement layer (2) is welded to the outermost adjacent sealing layer (1). The sealing layer (1) is made of a composition, and the composition is At least one semicrystalline polyamide thermoplastic polymer P1i, where i = 1 to n, and n is the number of sealing layers excluding polyether block amide (PEBA), Impact modifiers up to 50% by weight relative to the total weight of the composition, particularly impact modifiers up to less than 15% by weight, and more specifically, impact modifiers up to 12% by weight. The composition mainly contains up to 1.5% by weight of plasticizers relative to the total weight of the composition. The at least one polyamide thermoplastic polymer in each sealing layer may be the same or different. The present invention relates to a multilayer structure in which at least one of the composite reinforcing layers is made of a fibrous material in the form of continuous fibers impregnated with a composition, the composition mainly comprises at least one semicrystalline polyamide polymer P2j, where j=1 to m, and m is the number of reinforcing layers, and the number of carbon atoms per amide functional group of the polyamide in the outermost adjacent sealing layer (1) differs by up to 20% from the number of carbon atoms per amide functional group of the polyamide in the innermost reinforcing layer (2).

[0019] The inventors have therefore unexpectedly found that the use of a semicrystalline polyamide thermoplastic polymer P1i, more specifically a short-chain or long-chain semicrystalline polyamide thermoplastic polymer P1i, containing a limited proportion of impact modifiers and plasticizers for a sealing layer, and a semicrystalline thermoplastic polymer P2j for the matrix of a composite material, wherein the composite material is welded to the sealing layer, and the two polymers P1i and P2j of the sealing layer adjacent to the composite reinforcement layer differ by up to 20% in the number of carbon atoms per amide functional group, makes it possible to achieve a structure suitable for transporting, distributing, or storing hydrogen, more specifically a structure suitable for storing hydrogen, and an increase in the maximum operating temperature, which can reach up to 120°C, and thus makes it possible to increase the tank filling rate. [Modes for carrying out the invention]

[0020] "Multilayer structure" means a tank that includes or consists of several layers, namely several sealing layers and several reinforcing layers, or one sealing layer and several reinforcing layers, or several sealing layers and one reinforcing layer, or one sealing layer and one reinforcing layer.

[0021] A multilayer structure is therefore understood to exclude pipes or tubes.

[0022] Polyether block amide (PEBA) is a copolymer having an amide unit (Ba1) and a polyether unit (Ba2), wherein the amide unit (Ba1) is a unit obtained from at least one amino acid, or a unit obtained from at least one lactam, or: - Polycondensation of at least one diamine, wherein the diamine is preferably selected from linear or branched aliphatic diamines, or mixtures thereof, and - corresponds to an aliphatic repeating unit selected from units X.Y obtained by polycondensation of at least one dicarboxylic acid, said dicarboxylic acid being preferentially selected from linear or branched aliphatic dicarboxylic acids, or mixtures thereof, said diamine and said dicarboxylic acid contain 4 to 36 carbon atoms, advantageously 6 to 18 carbon atoms, said polyether unit (Ba2) is derived in particular from at least one polyalkylene ether polyol, in particular a polyalkylene ether diol. In one embodiment, the composition of the constituents of said sealing layer is free of a nucleating agent.

[0023] Nucleating agents are known to those skilled in the art, and the term refers to a substance which, when incorporated into a polymer, forms nuclei for crystal growth in the molten polymer.

[0024] These may be selected, for example, from microtalc, carbon black, silica, titanium dioxide and nanoclays.

[0025] In another embodiment, the composition of the constituents of said sealing layer is free of a nucleating agent and a plasticizer.

[0026] In one embodiment, said structure also lacks an outermost layer adjacent to the outermost layer of a composite reinforcement made of polyamide polymer.

[0027] In one embodiment, said multilayer structure consists only of two layers, a sealing layer and a reinforcing layer.

[0028] The one or more sealing layers are the innermost layer relative to the composite reinforcing layer that is the outermost layer.

[0029] The tank may be a tank for mobile storage of hydrogen, i.e., on a truck for transporting hydrogen, on a vehicle for transporting hydrogen and supplying hydrogen-based fuel cells, for example, on a train for supplying hydrogen, or on a drone for supplying hydrogen, but it may also be a tank for fixed storage of hydrogen at a base for distributing hydrogen to vehicles.

[0030] Advantageously, the sealing layer (1) does not leak hydrogen at 23°C, i.e., the hydrogen permeability at 23°C is less than 500 cc.mm / m2.24h.atm at 0% relative humidity (RH).

[0031] In one embodiment, the one or more sealing layers are mainly At least one polyamide thermoplastic polymer P1i, where i=1 to n, where n is the number of sealing layers excluding polyether block amide (PEBA) and PA11, and is semi-crystalline. It consists of a composition containing [the specified element].

[0032] The composite reinforcement layer(s) are wrapped around the sealing layer by polymer-impregnated fiber ribbons (or tapes or rovings), which are deposited, for example, by filament winding.

[0033] If several layers are present, the polymers may be different.

[0034] If the polymer of the reinforcing layer is identical, several layers may be present, but advantageously, a single reinforcing layer is present, and this reinforcing layer has at least one full wrap around the sealing layer.

[0035] Even when a single layer is present, several continuous, complete windings can be fabricated around the sealing layer, forming the single layer.

[0036] This fully automated process, well known to those skilled in the art, makes it possible to select a winding angle for each layer that will give the final structure the ability to withstand internal pressure loads.

[0037] If several sealing layers are present, only the innermost layer of the sealing layer will be in direct contact with hydrogen.

[0038] If only one sealing layer and a composite reinforcement layer are present, then a multilayer structure of two layers is formed, and these two layers are then welded to each other, that is, they are in direct contact with each other and adhere to each other.

[0039] If several sealing layers and / or several composite reinforcing layers are present, the outermost layer of the sealing layer, and therefore the layer opposite the layer in contact with hydrogen, is welded to the innermost layer of the composite reinforcing layer, and thus directly contacts and adheres to one another.

[0040] The other composite reinforcement layers also bond to each other.

[0041] The other sealing layers also adhere to each other.

[0042] Advantageously, there is only one sealing layer and one reinforcing layer, and they are not welded to each other.

[0043] Regarding sealing layers (multiple layers possible) and thermoplastic polymer P1i One or more sealing layers may be present.

[0044] Each of the aforementioned layers consists of a composition mainly comprising at least one thermoplastic polymer P1i, where i corresponds to the number of layers present, and i is between 1 and 10, more specifically 1 and 5, and especially 1 and 3, with a preference being i=1.

[0045] The term "primarily" means that at least one of the polymers is present in an amount greater than 50% by weight of the total weight of the composition.

[0046] Advantageously, the at least one dominant polymer is present in an amount of more than 60% by weight, particularly more than 70% by weight, more specifically more than 80% by weight, and more specifically 90% by weight or more, based on the total weight of the composition.

[0047] The composition may also contain up to 50% by weight of impact modifiers and / or plasticizers and / or additives based on the total weight of the composition.

[0048] The additives may be selected from other polymers, antioxidants, heat stabilizers, UV absorbers, light stabilizers, lubricants, inorganic fillers, flame retardants, dyes, carbon black, and carbonaceous nanofillers. In particular, the additives may be selected from antioxidants, heat stabilizers, UV absorbers, light stabilizers, lubricants, inorganic fillers, flame retardants, dyes, carbon black, and carbonaceous nanofillers.

[0049] In one embodiment, the nucleating agent is excluded from the additives.

[0050] In another embodiment, the nucleating agent is excluded from the additives, in which case the composition also lacks a plasticizer.

[0051] The other polymer may be another semicrystalline thermoplastic polymer or a different polymer, in particular EVOH (ethylene vinyl alcohol).

[0052] Advantageously, the composition mainly comprises the thermoplastic polymer P1i, 0 to 50% by weight of an impact modifier, particularly 0 to less than 15% of an impact modifier, more specifically 0 to 12% of an impact modifier, 0 to 1.5% of a plasticizer, and 0 to 5% by weight of an additive, the totality of the components of the composition being equal to 100%.

[0053] Advantageously, the composition mainly consists of the thermoplastic polymer P1i, 0 to 50% by weight of an impact modifier, particularly 0 to less than 15% of an impact modifier, more specifically 0 to 12% of an impact modifier, 0 to 1.5% of a plasticizer, and 0 to 5% by weight of an additive, and the total amount of the constituent components of the composition is equal to 100%.

[0054] Advantageously, the composition mainly comprises the thermoplastic polymer P1i, 0 to 50% by weight of an impact modifier, particularly 0 to less than 15% of an impact modifier, more specifically 0 to 12% of an impact modifier, 0 to 1.5% of a plasticizer, and 0 to 5% by weight of an additive, the totality of the components of the composition being equal to 100%.

[0055] Advantageously, the composition mainly consists of the thermoplastic polymer P1i, 0 to 50% by weight of an impact modifier, particularly 0 to less than 15% of an impact modifier, more specifically 0 to 12% of an impact modifier, 0 to 1.5% of a plasticizer, and 0 to 5% by weight of an additive, and the total amount of the constituent components of the composition is equal to 100%.

[0056] Advantageously, the composition mainly comprises the thermoplastic polymer P1i, 0 to 50% by weight of an impact modifier, particularly 0 to less than 15% of an impact modifier, more specifically 0 to 12% of an impact modifier, 0 to 5% of a plasticizer, and 0 to 5% by weight of an additive, the totality of the components of the composition being equal to 100%.

[0057] Advantageously, the composition mainly consists of the thermoplastic polymer P1i, 0 to 50% by weight of an impact modifier, particularly 0 to less than 15% of an impact modifier, more specifically 0 to 12% of an impact modifier, 0 to 5% of a plasticizer, and 0 to 5% by weight of an additive, and the total amount of the constituent components of the composition is equal to 100%.

[0058] The at least one dominant polymer in each layer may be the same or different.

[0059] In one embodiment, a single dominant polymer is present in at least the sealing layer that adheres to the composite reinforcement layer.

[0060] In one embodiment, the composition comprises 0.1 to 50% by weight, particularly 0.1 to less than 15% by weight, and more specifically 0.1 to 12% by weight, of the total weight of the composition, of an impact-resistant modifier.

[0061] In one embodiment, the composition lacks a plasticizer.

[0062] In another embodiment, the composition comprises 0.1 to 50% by weight of an impact modifier, particularly 0.1 to less than 15% by weight, and more specifically 0.1 to 12% by weight of an impact modifier, relative to the total weight of the composition, and the composition lacks a plasticizer.

[0063] In yet another embodiment, the composition comprises, with respect to the total weight of the composition, 0.1 to 50% by weight of an impact modifier, particularly 0.1 to less than 15% by weight of an impact modifier and 0.1 to 1.5% by weight of a plasticizer.

[0064] Semicrystalline polyamide thermoplastic polymer P1i "Thermoplastic" or "semicrystalline polyamide thermoplastic polymer" refers to a material that is generally solid at ambient temperature, softens as the temperature rises, specifically after passing its glass transition temperature (Tg), may completely melt above a temperature called its melting point (Tm), and becomes solid again when the temperature falls below its crystallization temperature.

[0065] Tg, Tc, and Tm are determined by differential scanning calorimetry (DSC) in accordance with standards 11357-2:2013 and 11357-3:2013, respectively.

[0066] The number-average molecular weight (Mn) of the semicrystalline polyamide thermoplastic polymer is preferably in the range of 10,000 to 85,000, particularly 10,000 to 60,000, preferably 10,000 to 50,000, and even more preferably 12,000 to 50,000. These Mn values ​​can correspond to an intrinsic viscosity of 0.8 or higher when determined in m-cresol according to standard ISO 307:2007, but by changing the solvent (using m-cresol instead of sulfuric acid at a temperature of 20°C).

[0067] The nomenclature is used to define polyamides as described in ISO standard 1874-1:2011 "Plastiques - Materiaux polyamides(PA) pour moulage et extrusion - Partie 1: Designation", particularly on page 3 (Tables 1 and 2), and is well known to those skilled in the art.

[0068] Polyamides may be homopolyamides, copolyamides, or mixtures thereof.

[0069] In one embodiment, the thermoplastic polymer is a short-chain semicrystalline aliphatic polyamide, i.e., a polyamide with an average number of carbon atoms up to 9 per nitrogen atom, or a long-chain aliphatic polyamide, i.e., a polyamide with an average number of carbon atoms greater than 9, preferably greater than 10, per nitrogen atom.

[0070] In detail, the short-chain aliphatic polyamide is selected from PA6, PA610, PA612, and PA6 / polyolefin mixtures.

[0071] More specifically, the long-chain aliphatic polyamides are selected from polyamide 11 (PA11), polyamide 12 (PA12), polyamide 1010 (PA1010), polyamide 1012 (PA1012), polyamide 1212 (PA1012), or mixtures thereof or copolyamides thereof, more specifically from PA11 and PA12.

[0072] In one embodiment, the long-chain aliphatic polyamide is selected from polyamide 12 (PA12), polyamide 1010 (PA1010), polyamide 1012 (PA1012), polyamide 1212 (PA1012), or mixtures thereof or copolyamides thereof, particularly PA12.

[0073] In another embodiment, the semicrystalline polyamide thermoplastic polymer is a semicrystalline semi-aromatic polyamide, more specifically, a semicrystalline semi-aromatic polyamide with an average number of carbon atoms of more than 8, preferably more than 9, per nitrogen atom and a melting temperature of 240°C to less than 280°C.

[0074] Advantageously, semicrystalline polyamides are semi-aromatic polyamides, particularly semi-aromatic polyamides of formula X / YAr as described in EP1505099, specifically semi-aromatic polyamides of formula A / XT (wherein A is a unit obtained from an amino acid, a unit obtained from a lactam, and the formula (Ca diamine)(Cb diacid), where a represents the number of carbon atoms in the diamine and b represents the number of carbon atoms in the diacid, and a and b are each selected from units between 4 and 36, preferably between 9 and 18), where the unit (Ca diamine) is selected from linear or branched aliphatic diamines, alicyclic diamines and alkyl aromatic diamines, and the unit (Cb diacid) is a unit selected from linear or branched aliphatic diacids, alicyclic diacids and aromatic diacids.

[0075] XT represents a unit obtained from the polycondensation of Cx diamine and terephthalic acid, where x represents the number of carbon atoms in the Cx diamine, and x is between 5 and 36, preferably between 9 and 18, and has formulas A / 5T, A / 6T, A / 9T, A / 10T or A / 11T, in particular, where A is a polyamide as defined above, and in detail polyamides include PA MPMDT / 6T, PA11 / 10T, PA 5T / 10T, PA 11 / BACT, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA 11 / BACT / 6T, PA 11 / MPMDT / 6T, PA 11 / MPMDT / 10T, PA 11 / BACT / 10T, PA The chainring can be selected from either 11 / MXDT / 10T or 11 / 5T / 10T.

[0076] In detail, the semi-aromatic semi-crystalline polyamides are selected from polyamides 11 / 5T, 11 / 6T, or 11 / 10T, MXDT / 10T, MPMDT / 10T, and BACT / 10T.

[0077] T corresponds to terephthalic acid, MXD corresponds to m-xylylenediamine, MPMD corresponds to methylpentamethylenediamine, and BAC corresponds to bis(aminomethyl)cyclohexane. The semi-aromatic polyamides defined above have a Tg of 80°C or higher.

[0078] Advantageously, each sealing layer consists of a composition containing the same type of polyamide.

[0079] The composition containing the polymer P1i may be black and can absorb radiation suitable for welding performed after the composite reinforcing layer is wrapped around the sealing layer.

[0080] When welding is required, there are various methods that enable the welding of elements made of polyamide thermoplastic polymers. Thus, contact or non-contact heating blades, ultrasonic, infrared, induction, vibration, rotation to weld one element to the other, or even laser welding can be used.

[0081] In detail, the welding of polyamide thermoplastic polymer elements by laser welding may require that the two elements to be welded have different properties with respect to radiation, specifically laser radiation. One of these elements must be transparent to radiation, specifically laser radiation, and the other must absorb radiation, specifically laser radiation. The radiation, specifically laser radiation, passes through the transparent portion and then reaches the absorbing element, where it is converted into heat. This causes the contact area between the two elements to melt, and thus welding occurs.

[0082] In the case of carbon fibers, it is preferable to melt the interface during removal.

[0083] To make them absorbent, various additives, such as carbon black, are known to be added, which causes the polymer to turn black and absorb radiation suitable for welding.

[0084] In one embodiment, welding is performed by a system selected from laser, infrared (IR) heating, LED heating, induction or microwave heating, or high-frequency (HF) heating.

[0085] When welding is performed by laser welding, composition P1i contains a carbonaceous filler.

[0086] When welding is performed by induction, composition P1i contains metal particles.

[0087] Advantageously, welding is performed using a laser system.

[0088] Regarding impact resistance modifiers The impact modifier may be any impact modifier, as long as it is a polymer that has a coefficient lower than that of the resin and has good adhesion to the matrix in order to dissipate crack energy.

[0089] The impact resistance modifiers are advantageously composed of polymers, more specifically polyolefins, having a flexural modulus of less than 100 MPa and a Tg (inflection point of a DSC thermogram, measured according to standard 11357-2) below 0°C, as measured according to standard ISO 178.

[0090] In one embodiment, PEBA is excluded from the definition of an impact modifier.

[0091] The polyolefins used as impact modifiers may be functionalized or unfunctionalized, or may be a mixture of at least one functionalized polyolefin and / or at least one unfunctionalized polyolefin. For simplicity, polyolefins are denoted as (B), functionalized polyolefins as (B1), and unfunctionalized polyolefins as (B2) below.

[0092] Unfunctionalized polyolefins (B2) are classically homopolymers or copolymers of alpha-olefins or diolefins, such as ethylene, propylene, 1-butene, 1-octene, and butadiene. Examples include: - Polyethylene, specifically LDPE, HDPE, LLDPE (linear low-density polyethylene), VLDPE (very low-density polyethylene), and metallocene polyethylene homopolymers and copolymers. - Propylene homopolymer or copolymer, - Ethylene / alpha-olefin copolymers, such as ethylene / propylene, EPR (abbreviation for ethylene-propylene-rubber), and ethylene / propylene / diene (EPDM), - Styrene / ethylene-butene / styrene (SEBS), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), styrene / ethylene-propylene / styrene (SEPS) block copolymers, - A copolymer in which the proportion of comonomers of ethylene and at least one product selected from salts or esters of unsaturated carboxylic acids, such as alkyl (meth)acrylates (e.g., methyl acrylate), or vinyl esters of saturated carboxylic acids, such as vinyl acetate (EVA), can reach 40% by weight.

[0093] Functionalized polyolefins (B1) can be polymers of alpha-olefins having reaction units (functional groups), such reaction units being acids, anhydrides, or epoxy functional groups. For example, the aforementioned polyolefins (B2) can be mentioned, which are grafted, copolymerized, or ternary polymerized by unsaturated epoxides, e.g., glycidyl (meth)acrylate, or by carboxylic acids or their corresponding salts or esters, e.g., (meth)acrylic acid (which can be completely or partially neutralized by metals, e.g., Zn), or even by carboxylic acid anhydrides, e.g., maleic anhydride. Functionalized polyolefins are, for example, PE / EPR mixtures, the ratio of which to weight can vary widely, e.g., from 40 / 60 to 90 / 10, and the mixtures are co-grafted with anhydrides, particularly maleic anhydride, according to graft rates of, for example, 0.01 to 5% by weight.

[0094] The functionalized polyolefin (B1) may be selected from the following (co)polymers grafted with maleic anhydride or glycidyl methacrylate, with grafting rates of, for example, 0.01 to 5% by weight: - Copolymers containing, for example, 35 to 80% by weight of ethylene, PE, PP, ethylene and propylene, butene, hexene or octene, - Ethylene / alpha-olefin copolymers, such as ethylene / propylene, EPR (abbreviation for ethylene-propylene-rubber), and ethylene / propylene / diene (EPDM), - Styrene / ethylene-butene / styrene (SEBS), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), styrene / ethylene-propylene / styrene (SEPS) block copolymers, - Ethylene and vinyl acetate copolymer (EVA) containing up to 40% by weight of vinyl acetate, - Ethylene and alkyl (meth)acrylate copolymers containing up to 40% by weight of alkyl (meth)acrylate, - Ethylene and vinyl acetate (EVA) and alkyl (meth)acrylate copolymers containing up to 40% by weight of comonomers.

[0095] Functionalized polyolefins (B1) can also be selected from ethylene / propylene copolymers (products described in EP-A-0,342,066) with monoamine polyamides (or polyamide oligomers) condensed with propylene, mainly grafted with maleic anhydride.

[0096] Functionalized polyolefin (B1) may also be a coat or terpolymer of at least the following units: (1) ethylene, (2) an alkyl (meth)acrylate or vinyl ester of a saturated carboxylic acid, and (3) an anhydride, such as maleic anhydride or (meth)acrylic acid, or an epoxy, such as glycidyl (meth)acrylate.

[0097] Examples of the latter type of functionalized polyolefin include the following copolymers, where ethylene is preferably equivalent to at least 60% by weight, and ter monomers (functional groups) are equivalent to, for example, 0.1 to 10% by weight of the copolymer: - Ethylene / alkyl (meth)acrylate / (meth)acrylic acid or maleic anhydride or glycidyl methacrylate copolymer, - Ethylene / vinyl acetate / maleic anhydride or glycidyl methacrylate copolymer, - Ethylene / vinyl acetate or alkyl (meth)acrylate / (meth)acrylic acid or maleic anhydride or glycidyl methacrylate copolymer.

[0098] In the copolymers mentioned above, (meth)acrylic acid can be chlorided with Zn or Li.

[0099] The term “alkyl(meth)acrylate” in (B1) or (B2) refers to C1 to C8 alkyl methacrylates and acrylates, and may be selected from methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethyl-hexyl acrylate, cyclohexyl acrylate, methyl methacrylate and ethyl methacrylate.

[0100] Furthermore, the previously cited polyolefin (B1) may also be crosslinked by any suitable method or agent (diepoxy, diacid, peroxide), and the term functionalized polyolefin also includes the previously cited polyolefin and a mixture of difunctional reagents that can react with them, such as diacids, dianhydrides, and diepoxys, or a mixture of at least two functionalized polyolefins that can react together.

[0101] The copolymers (B1) and (B2) mentioned above can be copolymerized by statistical or sequential methods and have linear or branched structures.

[0102] The molecular weight, MFI index, and density of these polyolefins may also vary widely, as those skilled in the art are aware. MFI, an abbreviation for melt flow index, is a measure of fluidity in the molten state. It is measured according to standard ASTM 1238.

[0103] Advantageously, the non-functionalized polyolefin (B2) is selected from polypropylene homopolymers or copolymers, any ethylene homopolymer or copolymer, and higher alpha-olefin comonomers, such as butene, hexene, octene, or 4-methyl-1-pentene. Examples include PP, high-density PE, medium-density PE, linear low-density PE, low-density PE, and very low-density PE. It is known to those skilled in the art that these polyethylenes are produced by the "free radical" method, the "Ziegler" catalyst method, or more recently, by a "metallocene" catalyst.

[0104] Advantageously, the functionalized polyolefin (B1) is selected from any polymer comprising alpha-olefin units and units having polar reactive functional groups such as epoxy, carboxylic acid, or carboxylic acid anhydride functional groups. Examples of such polymers include terpolymers of ethylene, alkyl acrylate, and maleic anhydride or glycidyl methacrylate, such as Lotader® from the applicant, or polyolefins grafted with maleic anhydride, such as Orevac® from the applicant, as well as terpolymers of ethylene, alkyl acrylate, and (meth)acrylic acid. Homopolymers or copolymers of polypropylene grafted with carboxylic acid anhydrides and then condensed with polyamide or monoamine polyamide oligomers may also be mentioned.

[0105] Advantageously, the composition constituting the sealing layer(s) lacks polyether block amide (PEBA). In this embodiment, PEBA is therefore excluded from the impact resistance modifier.

[0106] Advantageously, the permeable composition lacks core-shell particles or core-shell polymers.

[0107] A core-shell particle should be understood as a particle in which the first layer forms the nucleus, and all subsequent layers form their respective shells.

[0108] Core-shell particles are obtained by a method having several steps, including at least two steps. Such methods are described, for example, in documents US2009 / 0149600 or EP0,722,961.

[0109] Regarding plasticizers The plasticizer may be one commonly used in polyamide-based compositions.

[0110] Advantageously, a plasticizer with good thermal stability is used so as not to form fumes during the steps of mixing different polymers and transforming the resulting composition.

[0111] In detail, this plasticizer is Benzenesulfonamide derivatives, such as n-butylbenzenesulfonamide (BBSA), ethyltoluenesulfonamide (ETSA), N-cyclohexyltoluenesulfonamide, and ortho and para isomers of N-(2-hydroxypropyl)benzenesulfonamide (HP-BSA), Hydroxybenzoate esters, for example, 2-ethylhexyl p-hydroxybenzoate (EHPB) and 2-decylhexyl p-hydroxybenzoate (HDPB), Esters or ethers of tetrahydrofurfuryl alcohol, for example, oligoethyleneoxytetrahydrofurfuryl alcohol, Esters of citric acid or hydroxymalonic acid, such as oligoethylene oxymalonate It can be selected from the following.

[0112] The preferred plasticizer is n-butylbenzenesulfonamide (BBSA).

[0113] Another, and more specifically, preferred, plasticizer is N-(2-hydroxypropyl)benzenesulfonamide (HP-BSA). In fact, the latter has the advantage of preventing the formation of deposits ("die smears") in the extrusion screw and / or die during the extrusion conversion step.

[0114] Of course, it is possible to use a mixture of plasticizers.

[0115] Regarding composite reinforcement layers and polymer P2j Polymer P2j is a semicrystalline polyamide thermoplastic polymer, and the semicrystalline polyamide thermoplastic polymer has the same definition as described above.

[0116] One or more composite reinforcement layers may be present.

[0117] Each of the aforementioned layers consists of a fibrous material in the form of continuous fibers impregnated with a composition mainly comprising at least one thermoplastic polymer P2j, where j corresponds to the number of layers present.

[0118] j ranges from 1 to 10, more specifically from 1 to 5, and especially from 1 to 3, with j=1 being the preferred value.

[0119] The term "primarily" means that at least one of the polymers is present in an amount greater than 50% by weight of the total weight of the matrix of the composition and the composite.

[0120] Advantageously, the at least one dominant polymer is present in an amount of more than 60% by weight, particularly more than 70% by weight, more specifically more than 80% by weight, and more specifically 90% by weight or more, based on the total weight of the composition.

[0121] The composition may further comprise impact resistance modifiers and / or additives.

[0122] Additives may be selected from antioxidants, heat stabilizers, UV absorbers, light stabilizers, lubricants, inorganic fillers, flame retardants, plasticizers, and dyes.

[0123] In one embodiment, the additives exclude the nucleating agent.

[0124] Advantageously, the composition mainly consists of the polyamide thermoplastic polymer P2j, 0 to 15% by weight of an impact modifier, more specifically 0 to 12% by weight of an impact modifier, and 0 to 5% by weight of an additive, with the total amount of the constituent components of the composition equal to 100% by weight.

[0125] Advantageously, the composition mainly consists of the polyamide thermoplastic polymer P2j, 0 to 15% by weight of an impact modifier, more specifically 0 to 12% by weight of an impact modifier, and 0 to 5% by weight of an additive, with the total amount of the constituent components of the composition equal to 100% by weight.

[0126] Advantageously, the composition mainly consists of the polyamide thermoplastic polymer P2j, 0 to 15% by weight of an impact modifier, more specifically 0 to 12% by weight of an impact modifier, and 0 to 5% by weight of an additive, with the total amount of the constituent components of the composition equal to 100% by weight.

[0127] Advantageously, the composition mainly consists of the polyamide thermoplastic polymer P2j, 0 to 15% by weight of an impact modifier, more specifically 0 to 12% by weight of an impact modifier, and 0 to 5% by weight of an additive, with the total amount of the constituent components of the composition equal to 100% by weight.

[0128] The at least one dominant polymer in each layer may be the same or different.

[0129] In one embodiment, each reinforcing layer contains the same type of polyamide.

[0130] Polymer P2j Polyamide thermoplastic polymer P2j "Thermoplastic" or "semicrystalline polyamide thermoplastic polymer" refers to a material that is generally solid at ambient temperature, softens as the temperature rises, specifically after passing its glass transition temperature (Tg), may completely melt above a temperature called its melting point (Tm), and becomes solid again when the temperature falls below its crystallization temperature.

[0131] Tg, Tc, and Tm are determined by differential scanning calorimetry (DSC) in accordance with standards 11357-2:2013 and 11357-3:2013, respectively.

[0132] The number-average molecular weight Mn of the polyamide thermoplastic polymer P2j is preferably in the range of 10,000 to 40,000, and more preferably in the range of 10,000 to 30,000. These Mn values ​​can correspond to an intrinsic viscosity of 0.8 or higher when determined in m-cresol according to standard ISO 307:2007, but by changing the solvent (using m-cresol instead of sulfuric acid at a temperature of 20°C).

[0133] The nomenclature is used to define polyamides as described in ISO standard 1874-1:2011 "Plastiques - Materiaux polyamides(PA) pour moulage et extrusion - Partie 1: Designation", particularly on page 3 (Tables 1 and 2), and is well known to those skilled in the art.

[0134] Polyamides may be homopolyamides, copolyamides, or mixtures thereof.

[0135] In one embodiment, the thermoplastic polymer is a short-chain semicrystalline aliphatic polyamide, i.e., a polyamide with an average number of carbon atoms up to 9 per nitrogen atom, or a long-chain aliphatic polyamide, i.e., a polyamide with an average number of carbon atoms greater than 9, preferably greater than 10, per nitrogen atom.

[0136] In detail, the short-chain aliphatic polyamide is selected from PA6, PA610, PA612, and PA6 / polyolefin mixtures.

[0137] More specifically, the long-chain aliphatic polyamides are selected from polyamide 11 (PA11), polyamide 12 (PA12), polyamide 1010 (PA1010), polyamide 1012 (PA1012), polyamide 1212 (PA1012), or mixtures thereof or copolyamides thereof, more specifically from PA11 and PA12.

[0138] In one embodiment, the long-chain aliphatic polyamide is selected from polyamide 12 (PA12), polyamide 1010 (PA1010), polyamide 1012 (PA1012), polyamide 1212 (PA1012), or mixtures thereof or copolyamides thereof, particularly PA12.

[0139] In another embodiment, the semicrystalline polyamide thermoplastic polymer is a semicrystalline semi-aromatic polyamide, more specifically, a semicrystalline semi-aromatic polyamide with an average number of carbon atoms of more than 8, preferably more than 9, per nitrogen atom and a melting temperature of 240°C to less than 280°C.

[0140] Advantageously, semicrystalline polyamides are semi-aromatic polyamides, particularly semi-aromatic polyamides of formula X / YAr as described in EP1505099, specifically semi-aromatic polyamides of formula A / XT (wherein A is a unit obtained from an amino acid, a unit obtained from a lactam, and the formula (Ca diamine)(Cb diacid), where a represents the number of carbon atoms in the diamine and b represents the number of carbon atoms in the diacid, and a and b are each selected from units between 4 and 36, preferably between 9 and 18), where the unit (Ca diamine) is selected from linear or branched aliphatic diamines, alicyclic diamines and alkyl aromatic diamines, and the unit (Cb diacid) is selected from linear or branched aliphatic diacids, alicyclic diacids and aromatic diacids.

[0141] XT represents a unit obtained from the polycondensation of Cx diamine and terephthalic acid, where x represents the number of carbon atoms in the Cx diamine, and x is between 5 and 36, preferably between 9 and 18, and has formulas A / 5T, A / 6T, A / 9T, A / 10T or A / 11T, in particular, where A is a polyamide as defined above, and in detail polyamides include PA MPMDT / 6T, PA11 / 10T, PA 5T / 10T, PA 11 / BACT, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA 11 / BACT / 6T, PA 11 / MPMDT / 6T, PA 11 / MPMDT / 10T, PA 11 / BACT / 10T, PA The chainring can be selected from either 11 / MXDT / 10T or 11 / 5T / 10T.

[0142] In detail, the semi-aromatic semi-crystalline polyamides are selected from polyamides 11 / 5T, 11 / 6T, or 11 / 10T, MXDT / 10T, MPMDT / 10T, and BACT / 10T.

[0143] T corresponds to terephthalic acid, MXD corresponds to m-xylylenediamine, MPMD corresponds to methylpentamethylenediamine, and BAC corresponds to bis(aminomethyl)cyclohexane. The semi-aromatic polyamides defined above have a Tg of 80°C or higher.

[0144] Regarding the structure The multilayer structure thus comprises at least one sealing layer and at least one composite reinforcing layer, the innermost reinforcing layer being welded to the outermost sealing layer and thus adhering to each other.

[0145] All existing sealing layers are bonded to each other, and all existing reinforcing layers are bonded to each other.

[0146] In one embodiment, the Tm of the polyamide of the outermost adjacent sealing layer (1) differs from that of the polyamide of the innermost reinforcing layer (2) by up to 30°C, as measured according to ISO 11357-3:2013.

[0147] In another embodiment, the Tg of the polyamide in the outermost adjacent sealing layer (1) differs from that of the polyamide in the innermost reinforcing layer (2) by up to 30°C, as measured according to ISO 11357-2:2013.

[0148] Advantageously, the Tm and Tg of the polyamide in the outermost adjacent sealing layer (1) differ from those of the polyamide in the innermost reinforcing layer (2) by up to 30°C.

[0149] In one embodiment, each sealing layer contains the same type of polyamide, and each reinforcing layer contains the same type of polyamide.

[0150] The multilayer structure may include up to 10 sealing layers and up to 10 composite reinforcing layers of different properties.

[0151] It is clear that the aforementioned multilayer structure is not necessarily symmetrical and therefore may contain more sealing layers than composite layers, or vice versa, but alternating layers and reinforcing layers cannot exist.

[0152] Advantageously, the multilayer structure includes 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 sealing layers and 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 composite reinforcing layers.

[0153] Advantageously, the multilayer structure includes one, two, three, four, or five sealing layers and one, two, three, four, or five composite reinforcing layers.

[0154] Advantageously, the multilayer structure includes one, two, or three sealing layers and one, two, or three composite reinforcing layers.

[0155] In one embodiment, the multilayer structure includes a single sealing layer and several reinforcing layers, wherein the reinforcing layers adjacent to the sealing layer are welded to the sealing layer, and the other reinforcing layers are wound directly around adjacent reinforcing layers.

[0156] In another embodiment, the multilayer structure includes a single reinforcing layer and several sealing layers, the reinforcing layer being welded to the adjacent sealing layers.

[0157] In one advantageous embodiment, the multilayer structure comprises a single sealing layer and a single composite reinforcing layer, the reinforcing layer being welded to the sealing layer.

[0158] Advantageously, in the multilayer structure, each sealing layer is made of a composition containing the same type of polyamide polymer P1i.

[0159] Advantageously, the polyamide P1i is identical in all sealing layers.

[0160] Advantageously, the polymer P1i is a short-chain aliphatic polyamide, more particularly selected from PA6, PA610, PA612 and PA6 / polyolefin mixtures, or a long-chain polyamide, more particularly selected from PA1010, PA1012, PA1212, PA11 and PA12, more particularly selected from PA11 and PA12, or a semi-aromatic polyamide, more particularly selected from polyamide 11 / 5T, 11 / 6T, 11 / 10T, MXDT / 10T, MPMDT / 10T and BACT / 10T.

[0161] Advantageously, in the multilayer structure, each reinforcing layer is composed of a composition containing the same type of polyamide polymer P2j.

[0162] Advantageously, the polyamide P2j is identical in all reinforcing layers.

[0163] Advantageously, the polymer P2j is a short-chain aliphatic polyamide, more particularly selected from PA6, PA610, and PA612; or a long-chain polyamide, more particularly selected from PA1010, PA1012, PA1212, PA11, and PA12; or a semi-aromatic polyamide, more particularly selected from polyamide 11 / 5T, 11 / 6T, 11 / 10T, MXDT / 10T, MPMDT / 10T, and BACT / 10T.

[0164] Advantageously, in the multilayer structure, each sealing layer is made of a composition containing the same type of polyamide polymer P1i, and each reinforcing layer is made of a composition containing the same type of polyamide polymer P2j.

[0165] Advantageously, the polymer P1i may be a short-chain aliphatic polyamide, more particularly selected from PA6, PA610, PA612 and PA6 / polyolefin mixtures, or a long-chain polyamide, more particularly selected from PA1010, PA1012, PA1212, PA11 and PA12, more particularly selected from PA11 and PA12, or a semi-aromatic polyamide, more particularly selected from polyamide 11 / 5T, 11 / 6T, 11 / 10T, MXDT / 10T, MPMDT / 10T and BACT / 10T. The polymer P2j is an aromatic polyamide, wherein the polymer P2j is a short-chain aliphatic polyamide, more particularly selected from PA6, PA610, and PA612; or a long-chain polyamide, more particularly selected from PA1010, PA1012, PA1212, PA11, and PA12; or a semi-polyamide aromatic polyamide, more particularly selected from polyamide 11 / 5T, 11 / 6T, 11 / 10T, MXDT / 10T, MPMDT / 10T, and BACT / 10T.

[0166] In one embodiment, the multilayer structure consists of a single reinforcing layer and a single sealing layer, wherein the polymer P1i is a short-chain aliphatic polyamide, more particularly selected from PA6, PA610, PA612 and PA6 / polyolefin, or a long-chain mixture, more particularly selected from PA1010, PA1012, PA1212, PA11 and PA12, more particularly selected from PA11 and PA12, or a semi-aromatic polyamide, more particularly polyamide 11 / 5T, 11 / 6T, 11 / 10T, MXDT / 10T, MPMDT / 10T The polymer P2j is a semi-aromatic polyamide selected from BACT / 10T, wherein the polymer P2j is a short-chain aliphatic polyamide, more specifically selected from PA6, PA610, PA612, or a long-chain polyamide, more specifically selected from PA1010, PA1012, PA1212, PA11, and PA12, more specifically selected from PA11 and PA12, or a semi-aromatic polyamide, more specifically selected from polyamide 11 / 5T, 11 / 6T, 11 / 10T, MXDT / 10T, MPMDT / 10T, and BACT / 10T.

[0167] In one embodiment, the multilayer structure consists of a single reinforcing layer and a single sealing layer, wherein the polymer P1i is a short-chain aliphatic polyamide, more specifically selected from PA6, PA610, PA612 and PA6 / polyolefin mixtures, and the polymer P2j is a short-chain aliphatic polyamide, more specifically selected from PA6, PA610, and PA612.

[0168] In one embodiment, the multilayer structure consists of a single reinforcing layer and a single sealing layer, wherein the polymer P1i is a short-chain aliphatic polyamide, more particularly selected from PA6, PA610, PA612 and PA6 / polyolefin mixtures, and the polymer P2j is a long-chain aliphatic polyamide, more particularly selected from PA1010, PA1012, PA1212, PA11 and PA12, more particularly selected from PA11 and PA12.

[0169] In one embodiment, the multilayer structure consists of a single reinforcing layer and a single sealing layer, wherein the polymer P1i is a short-chain aliphatic polyamide, more specifically selected from PA6, PA610, PA612 and PA6 / polyolefin mixtures, and the polymer P2j is a semi-aromatic polyamide, more specifically selected from polyamides 11 / 5T, 11 / 6T, 11 / 10T, MXDT / 10T, MPMDT / 10T and BACT / 10T.

[0170] In one embodiment, the multilayer structure consists of a single reinforcing layer and a single sealing layer, wherein the polymer P1i is a long-chain aliphatic polyamide, more specifically selected from PA1010, PA1012, PA1212, PA11 and PA12, and more specifically selected from PA11 and PA12, and the polymer P2j is a short-chain aliphatic polyamide, more specifically selected from PA6, PA610 and PA612.

[0171] In one embodiment, the multilayer structure consists of a single reinforcing layer and a single sealing layer, wherein the polymer P1i is a long-chain aliphatic polyamide, more particularly selected from PA1010, PA1012, PA1212, PA11 and PA12, and more particularly selected from PA11 and PA12, and the polymer P2j is a long-chain aliphatic polyamide, more particularly selected from PA1010, PA1012, PA1212, PA11 and PA12, and more particularly selected from PA11 and PA12.

[0172] In one embodiment, the multilayer structure consists of a single reinforcing layer and a single sealing layer, wherein the polymer P1i is a long-chain aliphatic polyamide, more specifically selected from PA1010, PA1012, PA1212, PA11 and PA12, more specifically selected from PA11 and PA12, and the polymer P2j is a semi-aromatic polyamide, more specifically selected from polyamides 11 / 5T, 11 / 6T, 11 / 10T, MXDT / 10T, MPMDT / 10T and BACT / 10T.

[0173] In one embodiment, the multilayer structure consists of a single reinforcing layer and a single sealing layer, wherein the polymer P1i is a semi-aromatic polyamide, more specifically selected from polyamides 11 / 5T, 11 / 6T, 11 / 10T, MXDT / 10T, MPMDT / 10T, and BACT / 10T, and the polymer P2j is a short-chain aliphatic polyamide, more specifically selected from PA6, PA610, and PA612.

[0174] In one embodiment, the multilayer structure consists of a single reinforcing layer and a single sealing layer, wherein the polymer P1i is a semi-aromatic polyamide, more specifically selected from polyamides 11 / 5T, 11 / 6T, 11 / 10T, MXDT / 10T, MPMDT / 10T, and BACT / 10T, and the polymer P2j is a long-chain aliphatic polyamide, more specifically selected from PA1010, PA1012, PA1212, PA11, and PA12, more specifically selected from PA11 and PA12.

[0175] In one embodiment, the multilayer structure consists of a single reinforcing layer and a single sealing layer, wherein the polymer P1i is a semi-aromatic polyamide, more specifically selected from polyamides 11 / 5T, 11 / 6T, 11 / 10T, MXDT / 10T, MPMDT / 10T and BACT / 10T, and the polymer P2j is a semi-aromatic polyamide, more specifically selected from polyamides 11 / 5T, 11 / 6T, 11 / 10T, MXDT / 10T, MPMDT / 10T and BACT / 10T.

[0176] Advantageously, the multilayer structure further comprises at least one outer layer made of a fibrous material consisting of continuous glass fibers impregnated with a permeable amorphous polymer, the outermost layer of the multilayer structure.

[0177] The aforementioned outer layer is a second reinforcing layer, but it is permeable, which allows text to be placed on the structure.

[0178] Regarding fibrous materials The fibers that make up the aforementioned fibrous material are, in detail, inorganic, organic, or plant fibers.

[0179] Advantageously, the fibrous material may or may not be sized.

[0180] The fibrous material may therefore contain up to 3.5% by weight of an organic material (of the thermosetting or thermoplastic resin type), which is called sizing.

[0181] Inorganic fibers include, for example, carbon fibers, glass fibers, basalt or basalt-based fibers, silica fibers, or silicon carbide fibers. Organic fibers include thermoplastic or thermosetting polymer-based fibers, such as semi-aromatic polyamide fibers, aramid fibers, or polyolefin fibers. Preferably, these are amorphous thermoplastic polymer-based, and if the thermoplastic polymer mixture is amorphous, they have a Tg higher than the glass transition temperature Tg of the polymer or thermoplastic polymer mixture constituting the pre-impregnation matrix, or if the thermoplastic polymer mixture is semi-crystalline, they have a Tg higher than the Tm of the polymer or thermoplastic polymer mixture constituting the pre-impregnation matrix. Advantageously, these are semi-crystalline thermoplastic polymer-based, and if the thermoplastic polymer mixture is amorphous, they have a melting temperature Tm higher than the Tg of the polymer or thermoplastic polymer mixture constituting the pre-impregnation matrix, or if the thermoplastic polymer mixture is semi-crystalline, they have a melting temperature Tm higher than the Tm of the polymer or thermoplastic polymer mixture constituting the pre-impregnation matrix. Therefore, there is no risk of melting during impregnation by the thermoplastic matrix of the final composite in the organic fibers constituting the fibrous material. Plant fibers include natural linen, hemp, lignin, bamboo, silk, spider silk in particular, sisal hemp, and other cellulose fibers, in particular viscose. These plant fibers may be used alone, treated with a coating layer, or coated to promote adhesion and impregnation of a thermoplastic polymer matrix.

[0182] Textile materials can be cloth, string, or woven fabrics made from fibers.

[0183] This could be considered equivalent to a fiber that uses a supporting thread.

[0184] These component fibers can be used individually or in mixtures. Therefore, organic fibers can be mixed with inorganic fibers to pre-impregnate them with thermoplastic polymer powder, forming a pre-impregnated fibrous material.

[0185] Organic fiber yarns can have several basis weights. These can further have several shapes. The component fibers of a fibrous material can also take the form of a mixture of these reinforcing fibers having different shapes. The fibers are continuous fibers.

[0186] Preferably, the fibrous material is selected from glass fibers, carbon fibers, basalt fibers or basalt-based fibers, or mixtures thereof, particularly carbon fibers.

[0187] This is used in the form of one roving or several rovings.

[0188] In another aspect, the present invention relates to a method for manufacturing a multilayer structure defined above, characterized by comprising the step of filament winding a reinforcing layer defined above around a sealing layer defined above.

[0189] All the characteristics detailed above also apply to methods. [Examples]

[0190] In all examples, the tank is obtained by rotationally molding the sealing layer (liner) at a temperature suitable for the properties of the thermoplastic resin used.

[0191] In the case of composite reinforcements, a fibrous material (tape) previously impregnated with thermoplastic resin is used. This tape is deposited by filament winding using a robot with a 1500W laser heater at a speed of 12 m / min, and there is no polymerization step.

[0192] Example 1 (Counterexample): A Type IV hydrogen storage tank consisting of epoxy composite reinforcement (Tg100℃), T700SC31E carbon fiber (manufactured by Toray), and a PA11 sealing layer.

[0193] Example 2: A Type IV hydrogen storage tank consisting of a T700SC31E carbon fiber PA11 composite reinforcement (manufactured by Toray) and a PA11 sealing layer.

[0194] The tanks thus obtained are subjected to a cyclic pressure test with pressures fluctuating between 10 and 800 bar. Water is used to apply the pressure. The test is stopped after 10,000 cycles.

[0195] Next, a strip approximately 1 cm wide is cut from the tank. Then, the adhesion between the liner and the composite material is measured by initiating a peel test at the interface and using a traction machine. The peel strength is expressed in N / cm strip width. In Example 1, peeling is observed at a value of 3 N / cm. In Example 2, the force reaches over 30 N / cm.

Claims

1. A multilayer structure configured to transport, distribute, and store hydrogen, particularly for storage, It includes at least one sealing layer (1) and at least one composite reinforcing layer (2) from the inside out, The innermost composite reinforcement layer (2) is welded to the outermost adjacent sealing layer (1). The sealing layer (1) is made of a composition, At least one semicrystalline polyamide thermoplastic polymer P1i, where i = 1 to n, and n is the number of sealing layers excluding polyether block amide (PEBA), Impact modifiers up to 50% by weight relative to the total weight of the composition, particularly impact modifiers up to less than 15% by weight, and more specifically, impact modifiers up to 12% by weight. Plasticizer up to 1.5% by weight relative to the total weight of the composition It mainly includes, The at least one polyamide thermoplastic polymer in each sealing layer may be the same or different. At least one of the composite reinforcing layers is made of a fibrous material in the form of continuous fibers impregnated with the composition, the composition mainly comprises at least one semicrystalline polyamide polymer P2j, where j = 1 to m, and m is the number of reinforcing layers. A multilayer structure in which the number of carbon atoms per amide functional group of the polyamide in the outermost adjacent sealing layer (1) differs by up to 20% from the number of carbon atoms per amide functional group of the polyamide in the innermost reinforcing layer (2).

2. The multilayer structure according to claim 1, characterized in that the Tm of the polyamide in the outermost adjacent sealing layer (1) differs from that of the polyamide in the innermost reinforcing layer (2) by up to 30°C, as measured according to ISO 11357-3:2013.

3. The multilayer structure according to claim 1, characterized in that the Tg of the polyamide in the outermost adjacent sealing layer (1) differs from that of the polyamide in the innermost reinforcing layer (2) by up to 30°C, as measured according to ISO 11357-2:2013.

4. The multilayer structure according to claim 2 or 3, characterized in that the Tm and Tg of the polyamide in the outermost adjacent sealing layer (1) differ from the Tm and Tg of the polyamide in the innermost reinforcing layer (2) by up to 30°C.

5. A multilayer structure according to any one of claims 1 to 4, characterized in that each sealing layer contains the same type of polyamide.

6. A multilayer structure according to any one of claims 1 to 4, characterized in that each reinforcing layer contains the same type of polyamide.

7. The multilayer structure according to claim 5 or 6, characterized in that each sealing layer contains the same type of polyamide, and each reinforcing layer contains the same type of polyamide.

8. A multilayer structure according to any one of claims 1 to 4, characterized by having a single sealing layer and a single reinforcing layer.

9. The multilayer structure according to any one of claims 1 to 8, characterized in that the polymer P1i is a short-chain aliphatic polyamide with an average number of carbon atoms up to 9 per nitrogen atom, more particularly a short-chain aliphatic polyamide selected from PA6, PA610, PA612 and PA6 / polyolefin mixtures, or a long-chain aliphatic polyamide with an average number of carbon atoms greater than 9, preferably greater than 10 per nitrogen atom, more particularly a long-chain aliphatic polyamide selected from PA1010, PA1012, PA1212, PA11 and PA12, more particularly PA11 and PA12, or a semi-aromatic polyamide, more particularly a semi-aromatic polyamide selected from polyamide 11 / 5T, 11 / 6T, 11 / 10T, MXDT / 10T, MPMDT / 10T and BACT / 10T.

10. The multilayer structure according to any one of claims 1 to 8, characterized in that the polymer P2j is a short-chain aliphatic polyamide with an average number of carbon atoms up to 9 per nitrogen atom, more particularly a short-chain aliphatic polyamide selected from PA6, PA610, and PA612, or a long-chain aliphatic polyamide with an average number of carbon atoms greater than 9, preferably greater than 10 per nitrogen atom, more particularly a long-chain aliphatic polyamide selected from PA1010, PA1012, PA1212, PA11, and PA12, more particularly PA11 and PA12, or a semi-aromatic polyamide, more particularly a semi-aromatic polyamide selected from polyamide 11 / 5T, 11 / 6T, 11 / 10T, MXDT / 10T, MPMDT / 10T, and BACT / 10T.

11. The polymer P1i is a short-chain aliphatic polyamide with an average number of carbon atoms up to 9 per nitrogen atom, more specifically PA6, PA610, PA612, or PA6 / polyolefin mixture, or a long-chain aliphatic polyamide with an average number of carbon atoms greater than 9, preferably greater than 10, per nitrogen atom, more specifically PA1010, PA1012, PA1212, PA11, PA12, more specifically PA11 or PA12, or a semi-aromatic polyamide, more specifically a semi-aromatic polyamide selected from polyamide 11 / 5T or 11 / 6T or 11 / 10T, MXDT / 10T, MPMDT / 10T, and BACT / 10T, and the polymer P2j is a nitrogen The multilayer structure according to claim 9 or 10, characterized in that it is a short-chain aliphatic polyamide with an average number of carbon atoms up to 9 per atom, more particularly selected from PA6, PA610, and PA612, or a long-chain polyamide with an average number of carbon atoms of more than 9, preferably more than 10 per nitrogen atom, more particularly selected from PA1010, PA1012, PA1212, PA11, and PA12, more particularly selected from PA11 and PA12, or a semi-aromatic polyamide, more particularly selected from polyamide 11 / 5T, 11 / 6T, 11 / 10T, MXDT / 10T, MPMDT / 10T, and BACT / 10T.

12. The multilayer structure according to any one of claims 1 to 11, characterized in that the fibrous material of the composite reinforcing layer is selected from glass fibers, carbon fibers, basalt fibers or basalt-based fibers, or mixtures thereof, particularly carbon fibers.

13. The multilayer structure according to any one of claims 1 to 12, wherein the structure further comprises at least one outer layer made of a fibrous material consisting of continuous glass fibers impregnated with a permeable amorphous polymer, the layer being the outermost layer of the multilayer structure.

14. A method for manufacturing a multilayer structure according to any one of claims 1 to 13, characterized by comprising the step of welding a reinforcing layer according to claim 1 to a sealing layer according to claim 1.