Multilayer structure for transporting or storing hydrogen

Abstract

The present invention provides a multilayer structure configured for transporting, distributing, or storing hydrogen. [Solution] A multilayer structure comprising a sealing layer (1) and at least one composite reinforcing layer (2) from the inside out, wherein the sealing layer comprises a layer (a) made of a composition mainly comprising a short-chain polyamide thermoplastic polymer, an impact-resistant modifier of more than 15% and up to 50% by weight, or mainly a semi-crystalline long-chain polyamide thermoplastic polymer, an impact-resistant modifier of up to 50% by weight relative to the total weight of the composition, and a plasticizer of up to 3% by weight relative to the total weight of the composition, a hydrogen barrier layer made of PVDF or EVOH, and a layer (b) (=layer (a)), the innermost part of the composite reinforcing layer (2) is wound around the sealing layer (1), 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 polymer P1j, where j=1 to m, and m is the number of reinforcing layers.

Description

Technical Field

[0001] This patent application relates to a multilayer composite structure for transporting, distributing or storing hydrogen, particularly for distributing or storing hydrogen, and a method for producing the same structure.

Background Art

[0002] Hydrogen tanks are currently attracting a great deal of attention from a number of manufacturers, especially in the automotive sector. One of the required goals is to propose further low-emission vehicles. Therefore, it is aimed to gradually replace internal combustion engine vehicles, 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, the battery may need to protect it from impacts and from the external environment, which can be at 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 cells of the battery and to prolong its life. Conversely, for example in winter, it may be necessary to raise the temperature of the battery in order to optimize its operation.

[0004] Furthermore, electric vehicles still suffer from several problems today, namely battery range, the use of rare earth metals in these batteries, non-renewable resources, charging times much longer than the time taken to fill a tank, and the problem of electricity generation to enable battery charging in various countries.

[0005] Therefore, hydrogen is an alternative to electric batteries since hydrogen can be converted into electricity by a fuel cell and thus supply power to an electric vehicle.

[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 made of fibers (glass, aramid, carbon), 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 a severe external attack.

[0008] The liner must possess certain principle characteristics:

[0009] Potential conversion methods include extrusion blow molding, rotational molding, injection molding, or extrusion.

[0010] Low hydrogen permeability, or in fact, the permeability of the liner, is a crucial factor in limiting hydrogen leakage from the tank.

[0011] Good mechanical properties (fatigue) at low temperatures (-40 to -70°C)

[0012] Heat resistance at 120°C

[0013] 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 overheat more significantly, then reach a temperature of about 100°C.

[0014] The performance and safety of hydrogen tanks can be evaluated at the Reference European Laboratory (GasTeF: Hydrogen Tank Test Facility), as described by Galassi et al. (World hydrogen energy conference 2012, Onboard compressed hydrogen storage: fast filing experiments and simulations, Energy Procedia 29 (2012), pp. 192-200).

[0015] The first generation of Type IV tanks used high-density polyethylene (HDPE) based liners.

[0016] 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.

[0017] Polyamide PA6-based liners have been under development for many years.

[0018] Nevertheless, PA6 has the disadvantage of having low resistance to cold.

[0019] Application US2014 / 008373 relates to a lightweight storage cylinder for high-pressure compressed gas, having a liner surrounded by a restraining layer, The line, First inner layer of impact-resistant modified polyamide (PA) that comes into contact with gas, A thermoplastic outer layer in contact with the restraining layer, and This document describes a cylinder that includes an adhesive bonding layer between a first impact-resistant improved PA inner layer and an outer thermoplastic layer.

[0020] French patent application FR2923575 describes a tank for storing fluid under high pressure, comprising metal end pieces at each of its ends along its axis, wherein a liner surrounds the end pieces, and a structural layer made of thermosetting resin-impregnated fibers surrounds the liner.

[0021] 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.

[0022] 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 project]

[0023] These problems are solved by providing the multilayer structure of the present invention configured for transporting, distributing, or storing hydrogen.

[0024] Throughout this specification, the terms “liner” and “sealing sheath” have the same meaning.

[0025] The present invention therefore provides a multilayer structure configured for transporting, distributing and storing hydrogen, more specifically for storing hydrogen, comprising, from inside to outside, a sealing layer (1) and at least one composite reinforcing layer (2), The aforementioned sealing layer is applied from the inside outwards. A layer (a) consisting of a composition, wherein the composition is A short-chain polyamide thermoplastic polymer with a Tm of more than 160 °C, specifically more than 170 °C, measured according to ISO 11357-3:2013, More than 15% and up to 50% of an impact modifier, or Or A long-chain semi-crystalline polyamide thermoplastic polymer with a Tm of more than 160 °C, specifically more than 170 °C, measured according to ISO 11357-3:2013, Up to 50% of an impact modifier, especially less than 15% of an impact modifier, specifically up to 12% of an impact modifier, based on the total weight of the composition, Up to 3% of a plasticizer based on the total weight of the composition, Mainly comprising layer (a), Optionally a layer of a binder, Specifically a hydrogen barrier layer made of a fluoropolymer, specifically PVDF or EVOH, preferably EVOH, Optionally a layer of a binder, A layer (b) consisting of a composition, wherein the composition is A short-chain polyamide thermoplastic polymer with a Tm of more than 160 °C, specifically more than 170 °C, measured according to ISO 11357-3:2013, Mainly comprising more than 15% and up to 50% of an impact modifier, or Or A long-chain semi-crystalline polyamide thermoplastic polymer with a Tm of more than 160 °C, specifically more than 170 °C, measured according to ISO 11357-3:2013, Up to 50% of an impact modifier, especially less than 15% of an impact modifier, specifically up to 12% of an impact modifier, based on the total weight of the composition, Up to 3% of a plasticizer based on the total weight of the composition, Mainly comprising layer (b), The innermost said composite reinforcing layer (2) is wound around the sealing layer (1), 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 polymer P1j, where j=1 to m, and m is the number of reinforcing layers, and more specifically comprises an epoxy resin or epoxy-based resin.

[0026] PVDF is equivalent to polyvinylidene fluoride.

[0027] EVOH is equivalent to ethylene vinyl alcohol.

[0028] Advantageously, the Tm of the short-chain polyamide thermoplastic polymer is greater than 200°C, as measured according to ISO 11357-3:2013.

[0029] The inventors have therefore unexpectedly found that by using a sealing layer comprising impact modifiers and plasticizers in proportions limited to above and below the barrier layer, and a composite matrix comprising different polymers, particularly epoxy resins or epoxy-based resins, and the composite being wrapped around the sealing layer with two significantly impact-modified short-chain semicrystalline polyamide thermoplastic polymers or long-chain semicrystalline polyamide thermoplastic polymers, it is possible to achieve a structure suitable for transporting, distributing, or storing hydrogen, particularly an increase in the maximum temperature of use, which can reach up to 120°C, and thus an increase in the tank filling rate. [Modes for carrying out the invention]

[0030] "Multilayer structure" should be understood to mean a tank consisting of several layers, namely a sealing layer comprising at least three layers, and at least one reinforcing layer, more specifically a single reinforcing layer.

[0031] A multilayer structure is therefore understood to exclude pipes or tubes.

[0032] The tank may be for mobile storage of hydrogen, i.e., on a truck for transporting hydrogen, on a vehicle for transporting hydrogen and supplying hydrogen to 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.

[0033] In the first modification, the short-chain or long-chain polyamide thermoplastic polymer in layer (a) excludes polyether block amide (PEBA).

[0034] Polyether block amides (PEBA) are copolymers having amide units (Ba1) and polyether units (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: - A polycondensation of at least one diamine, wherein the diamine is preferably selected from linear or branched aliphatic diamines, or mixtures thereof. - A polycondensation of at least one carboxylic acid diacid, wherein the diacid is preferably selected from linear or branched aliphatic diacids, or mixtures thereof, and corresponds to an aliphatic repeating unit selected from the units XY obtained from the polycondensation. The diamine and the diacid each contain 4 to 36 carbon atoms, preferably 6 to 18 carbon atoms. The polyether unit (Ba2) is derived in particular from at least one polyalkylene ether polyol, in particular from a polyalkylene ether diol.

[0035] In the second modification, the composition of layer (a) lacks a nucleating agent.

[0036] Nucleating agents are known to those skilled in the art, and the term refers to substances that, when incorporated into a polymer, form nuclei for the growth of crystals in a molten polymer.

[0037] These can be selected from, for example, microtalc, carbon black, silica, titanium dioxide, and nanoclay.

[0038] In the third variation, the short-chain or long-chain polyamide thermoplastic polymer of layer (a) excludes polyether block amide (PEBA), and the composition of layer (a) lacks a nucleating agent.

[0039] In the fourth variation, the short-chain or long-chain polyamide thermoplastic polymer in layer (b) excludes polyether block amide (PEBA).

[0040] In the fifth variation, the composition of layer (b) lacks a nucleating agent.

[0041] In the sixth variation, the short-chain or long-chain polyamide thermoplastic polymer of layer (b) excludes polyether block amide (PEBA), and the composition of layer (b) lacks a nucleating agent.

[0042] In the seventh variation, the short-chain or long-chain polyamide thermoplastic polymers of layer (a) and layer (b) exclude polyether block amide (PEBA).

[0043] In the eighth variation, the compositions of layer (a) and layer (b) lack a nucleating agent.

[0044] In the ninth variation, the short-chain or long-chain polyamide thermoplastic polymers of layer (a) and layer (b) exclude polyether block amide (PEBA), and the compositions of layer (a) and layer (b) lack a nucleating agent.

[0045] In one embodiment, the multilayer structure consists of a sealing layer and a reinforcing layer.

[0046] 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).

[0047] In one embodiment, PA11 is excluded from the composition of layer (a).

[0048] In one embodiment, PA11 is excluded from the composition of layer (b).

[0049] In one embodiment, PA11 is excluded from the composition of layer (a) and the composition of layer (b).

[0050] 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.

[0051] If several reinforcing layers are present, the polymers will differ.

[0052] 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.

[0053] 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.

[0054] When there is only one sealing layer and one composite reinforcement layer, it thus becomes a multilayer structure of two layers (the sealing layer is considered a single layer), and these two layers can then come into direct contact with each other and adhere to each other, especially since the composite reinforcement layer is wrapped around the sealing layer.

[0055] If several composite reinforcing layers are present, the outermost layer (b) of the sealing layer, and thus the layer opposite to the layer in contact with hydrogen, may or may not be bonded to the innermost layer of the composite reinforcing layer.

[0056] Other composite reinforcement layers may or may not be bonded to each other.

[0057] Other sealing layers may or may not be bonded to each other.

[0058] Advantageously, there is only one sealing layer and one reinforcing layer, and they do not adhere to each other.

[0059] Advantageously, there is a single sealing layer and a single reinforcing layer that are not bonded to each other, and the reinforcing layer consists mainly of a fibrous material in the form of continuous fibers impregnated with a composition mainly comprising at least one polymer P1j, more specifically an epoxy resin or epoxy-based resin.

[0060] In one embodiment, there is only one sealing layer and one reinforcing layer, which are not bonded to each other, and the reinforcing layer consists of a fibrous material in the form of continuous fibers impregnated with a composition mainly containing a polymer P1j, which is an epoxy resin or epoxy-based resin.

[0061] The term "epoxy-based" throughout this specification means that epoxy is equivalent to at least 50% by weight of the matrix.

[0062] Regarding the sealing layer and the thermoplastic polymers of layers (a) and (b): Each of the layers (a) and (b) consists mainly of a composition comprising at least one short-chain semicrystalline polyamide thermoplastic polymer or a long-chain semicrystalline polyamide thermoplastic polymer.

[0063] The term "short chain" means that polyamides have between 4 and fewer than 8 carbon atoms per nitrogen atom, specifically between 6 and fewer than 8 carbon atoms.

[0064] The term "long chain" means that the polyamide has eight or more carbon atoms per nitrogen atom, preferably more than nine, and more specifically more than ten.

[0065] 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.

[0066] 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.

[0067] If the polyamide is long-chain, the composition of layer (a) may also include up to 50% by weight of an impact modifier and / or up to 3% by weight of a plasticizer and / or up to 5% of an additive, relative to the total weight of the composition.

[0068] The additives, excluding the nucleating agent, 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, excluding the nucleating agent, may be selected from antioxidants, heat stabilizers, UV absorbers, light stabilizers, lubricants, inorganic fillers, flame retardants, dyes, carbon black, and carbonaceous nanofillers.

[0069] The other polymer may be another semicrystalline thermoplastic polymer or a different polymer, in particular EVOH (ethylene vinyl alcohol).

[0070] Advantageously, the composition of layer (a) mainly comprises the long-chain polyamide thermoplastic polymer, 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 3% of a plasticizer, and 0 to 5% by weight of an additive, the totality of the components of the composition being equal to 100%.

[0071] Advantageously, the composition of layer (a) mainly consists of the long-chain polyamide thermoplastic polymer, 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 3% of a plasticizer, and 0 to 5% by weight of an additive, and the totality of the components of the composition is equal to 100%.

[0072] In one embodiment, a single dominant polymer is present in the sealing layer.

[0073] In one embodiment, the composition of layer (a) includes 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, based on the total weight of the composition.

[0074] In one embodiment, the composition of layer (a) lacks a plasticizer.

[0075] In another embodiment, the composition of layer (a) 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 of layer (a) is free of plasticizers.

[0076] In yet another embodiment, the composition of layer (a) comprises 0.1 to 50% by weight, particularly 0.1 to less than 15% by weight of an impact modifier and 0.1 to 1.5% by weight of a plasticizer, based on the total weight of the composition.

[0077] The composition of layer (a), if the polyamide is short-chain, also includes, in terms of weight, more than 15% and up to 50% impact modifiers and / or up to 3% plasticizers and / or up to 5% additives, relative to the total weight of the composition.

[0078] The additives, excluding the nucleating agent, 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, excluding the nucleating agent, may be selected from antioxidants, heat stabilizers, UV absorbers, light stabilizers, lubricants, inorganic fillers, flame retardants, dyes, carbon black, and carbonaceous nanofillers.

[0079] The other polymer may be another semicrystalline thermoplastic polymer or a different polymer, in particular EVOH (ethylene vinyl alcohol).

[0080] Advantageously, the composition of layer (a) mainly comprises the short-chain polyamide thermoplastic polymer, more than 15% to 50% by weight of an impact modifier, particularly 20% to 50% by weight of an impact modifier, more specifically 30% to 40% by weight of an impact modifier, 0% to 3% of a plasticizer, and 0% to 5% by weight of an additive, the totality of the components of the composition being equal to 100%.

[0081] Advantageously, the composition of layer (a) mainly consists of the short-chain polyamide thermoplastic polymer, more than 15% to 50% by weight of an impact modifier, particularly 20% to 50% by weight of an impact modifier, 0 to 3% of a plasticizer, and 0 to 5% by weight of an additive, and the totality of the components of the composition is equal to 100%.

[0082] In one embodiment, a single dominant polymer is present in the sealing layer.

[0083] In one embodiment, the composition of layer (a) includes an impact-resistant modifier, comprising more than 15% to 50% by weight of the impact-resistant modifier, particularly 20% to 50% by weight of the impact-resistant modifier, based on the total weight of the composition.

[0084] In one embodiment, the composition of layer (a) lacks a plasticizer.

[0085] In another embodiment, the composition of layer (a) 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 of layer (a) is free of plasticizers.

[0086] In yet another embodiment, the composition of layer (a) 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, and 0.1 to 1.5% by weight of a plasticizer.

[0087] With respect to layer (b), it has the same properties as those detailed above for layer (a), whether with respect to short-chain polyamides or long-chain polyamides.

[0088] The polyamide of layer (a) and the polyamide of layer (b) may be the same or different, and in detail they are the same.

[0089] Short-chain and long-chain semi-crystalline polyamide thermoplastic polymers "Polyamide thermoplastic polymers" or "semi-crystalline polyamide thermoplastic polymers" refer to materials that are generally solid at ambient temperature. These materials soften as the temperature rises, specifically after passing the glass transition temperature (Tg), and may exhibit clear melting when they pass what is called the melting point (Tm). When the temperature drops below the crystallization temperature, they become solid again.

[0090] Tg, Tc, and Tm are determined by differential scanning calorimetry (DSC) in accordance with standards 11357-2:2013 and 11357-3:2013, respectively.

[0091] 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).

[0092] The nomenclature used to define polyamides is 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.

[0093] Polyamides may be homopolyamides, copolyamides, or mixtures thereof.

[0094] In one embodiment, the thermoplastic polymer is a long-chain aliphatic polyamide, that is, a polyamide having an average number of carbon atoms of 8 or more, preferably more than 9, and more specifically more than 10, per nitrogen atom.

[0095] In detail, long-chain aliphatic polyamides are: Polyamide 11 (PA11), polyamide 12 (PA12), polyamide 1010 (PA1010), polyamide 1012 (PA1012), polyamide 1212 (PA1012), or mixtures thereof, or copolyamides thereof, more specifically selected from PA11 and PA12.

[0096] More specifically, polyamide 11 (PA11), polyamide 12 (PA12), polyamide 1012 (PA1012), polyamide 1212 (PA1012), or mixtures thereof, or copolyamides thereof, in particular PA11 and PA12.

[0097] In one embodiment, the long-chain aliphatic polyamide is: Polyamide 12 (PA12), polyamide 1010 (PA1010), polyamide 1012 (PA1012), polyamide 1212 (PA1012), or mixtures thereof, or copolyamides thereof, more specifically selected from PA12.

[0098] In another embodiment, the long-chain aliphatic polyamide is: Polyamide 12 (PA12), polyamide 1012 (PA1012), polyamide 1212 (PA1012), or mixtures thereof, or copolyamides thereof, more specifically selected from PA12.

[0099] In one embodiment, the thermoplastic polymer is a short-chain aliphatic polyamide, i.e., a polyamide having 4 to less than 8, more specifically 6 to less than 8, carbon atoms per nitrogen atom.

[0100] In detail, the short-chain aliphatic polyamide is selected from PA6, PA66, and PA6 / 66.

[0101] When welding is required, there are various methods for welding components made of polyamide thermoplastic polymers. Therefore, contact or non-contact heating blades, ultrasonic, infrared, vibration, rotation of the component to be welded, or even laser welding may be used.

[0102] 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.

[0103] The impact resistance modifier is advantageously comprised of a polymer, more specifically a polyolefin, 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.

[0104] In one embodiment, PEBA is excluded from the definition of an impact modifier.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] In the copolymers mentioned above, (meth)acrylic acid can be chlorided with Zn or Li.

[0113] 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.

[0114] 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.

[0115] The copolymers (B1) and (B2) mentioned above can be copolymerized by statistical or sequential methods and have linear or branched structures.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] Advantageously, the permeable composition lacks core-shell particles or core-shell polymers.

[0121] 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.

[0122] 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.

[0123] Regarding plasticizers The plasticizer may be one commonly used in polyamide-based compositions.

[0124] 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.

[0125] 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.

[0126] The preferred plasticizer is n-butylbenzenesulfonamide (BBSA).

[0127] 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.

[0128] Of course, it is possible to use a mixture of plasticizers.

[0129] Regarding the composite reinforcement layer and polymer P1j Polymer P1j may be a thermoplastic polymer or a thermosetting polymer.

[0130] One or more composite reinforcement layers may be present.

[0131] 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 P1j, where j corresponds to the number of layers present.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] The composition may further comprise impact resistance modifiers and / or additives.

[0136] Apart from nucleating agents, additives may be selected from antioxidants, heat stabilizers, UV absorbers, light stabilizers, lubricants, inorganic fillers, flame retardants, plasticizers, and dyes.

[0137] Advantageously, the composition mainly consists of the thermoplastic polymer P1j, 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.

[0138] The at least one dominant polymer in each layer may be the same or different.

[0139] In one embodiment, a single dominant polymer is present in at least the composite reinforcement layer and does not adhere to the sealing layer.

[0140] In one embodiment, each reinforcing layer comprises the same type of polymer, more specifically, an epoxy resin or epoxy-based resin.

[0141] Polymer P1j Thermoplastic polymer P1j Thermoplastics, or thermoplastic polymers, generally refer to materials that are solid at ambient temperature. These can be semi-crystalline or amorphous, more specifically semi-crystalline, and they soften as the temperature rises, more specifically after passing the glass transition temperature (Tg). If amorphous, they flow at higher temperatures, or if semi-crystalline, they may exhibit a sharp transition when passing the so-called melting point (Tm). They become solid again when the temperature drops below the crystallization temperature Tc (for semi-crystalline materials) and below the glass transition temperature (for amorphous materials).

[0142] Tg, Tc, and Tm are determined by differential scanning calorimetry (DSC) in accordance with standards 11357-2:2013 and 11357-3:2013, respectively.

[0143] The number-average molecular weight (Mn) of the thermoplastic polymer 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).

[0144] Examples of semi-crystalline thermoplastic polymers suitable for the present invention include: Copolymers, such as polyamide-polyether copolymers, and more specifically polyamides, including aromatic and / or alicyclic structures, polyester, Polyaryl ether ketone (PAEK), Polyetheretherketone (PEEK), Polyetherketoneketone (PEKK), Polyetherketone etherketone ketone (PEKEKK), Polyimide, more specifically polyetherimide (PEI) or polyamide-imide, Polylylsulfone (PSU), more specifically polyallylsulfone, for example, polyphenylsulfone (PPSU), Polyethersulfone (PES).

[0145] Semicrystalline polymers, and more specifically polyamides and their semicrystalline copolymers, are preferred.

[0146] The nomenclature used to define polyamides is described in detail on page 3 (Tables 1 and 2) of the ISO standard 1874-1:2011 "Plastiques -- Materiaux polyamides(PA) pour moulage et extrusion -- Partie 1: Designation" and is well known to those skilled in the art.

[0147] Polyamides may be homopolyamides, copolyamides, or mixtures thereof.

[0148] 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.

[0149] 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.

[0150] 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.

[0151] Thermosetting polymer P1j The thermosetting polymer is selected from epoxy resins or epoxy-based resins, polyesters, vinyl esters and polyurethanes, or mixtures thereof, in particular epoxy resins or epoxy-based resins.

[0152] Advantageously, each composite reinforcing layer consists of a composition containing the same type of polymer, in particular an epoxy resin or an epoxy-based resin.

[0153] The composition containing the polymer P1j is permeable to radiation suitable for welding.

[0154] In another embodiment, the composite reinforcing layer is wound around the sealing layer without any subsequent welding.

[0155] Regarding the binder The binder is an adhesive composition as described in EP2098580, namely - at least one polyamide designated A, having an average number of carbon atoms per nitrogen atom designated CA of from 4 to <8.5>, advantageously from 4 to 7, - at least one polyamide designated B, having a melting point of 180 °C or higher and an average number of carbon atoms per nitrogen atom designated CB of from 7 to 10, advantageously from 7. <5> to 9.5, - at least one polyamide designated C, having an average number of carbon atoms per nitrogen atom designated CC of from 9 to 18, advantageously from 10 to 18, and may be an adhesive composition containing At least 50% by weight of the composition is formed of one or more polyamides selected from polyamides A, B and C, The melting enthalpy of the weight-average mass of these polyamides inside the composition is greater than 25 J / g (DSC), The average number of carbon atoms per nitrogen atom of polyamides A, B and C further satisfies the following strict inequality: CA < CB < CC.

[0156] The binders include, for example, a composition based on 50% copolyamide 6 / 12 (70 / 30 weight ratio) having Mn 16,000, and a composition based on 50% copolyamide 6 / 12 (30 / 70 weight ratio) having Mn 16,000, a composition based on maleic anhydride-grafted PP (polypropylene) known as Mitsui's Admer QF551A, PA610 (having Mn 30,000 as separately defined) and 36% PA6 (having Mn 28,000), and 1.2% organic stabilizers (Great Lakes' 0.8% phenol Lowinox 44B25, Ciba's 0.2% phosphite Irgafos 168, Ciba's 0.2% anti-UV Tinuvin Compositions based on 312, PA612 (having Mn 29,000 as otherwise defined) and 36% PA6 (having Mn 28,000 as otherwise defined) and 1.2% organic stabilizers (0.8% phenol Lowinox 44B25 from Great Lakes, 0.2% phosphite Irgafos 168 from Ciba, and 0.2% anti-UV Tinuvin from Ciba), PA610 (having Mn 30,000 as otherwise defined) and 36% PA12 (having Mn 35,000 as otherwise defined), as well as 1.2% organic stabilizers (0.8% phenol Lowinox 44B25 from Great Lakes, 0.2% phosphite Irgafos 168 from Ciba, and 0.2% anti-UV Tinuvin from Ciba) A composition based on (consisting of 312), 40% PA6 (having Mn 28,000 and as otherwise defined), 40% PA12 (having Mn 35,000 and as otherwise defined), and 20% functionalized EPR Exxelor VA1801 (Exxon) and 1.2% organic stabilizer (consisting of 0.8% phenol Lowinox 44B25 of Great Lakes, 0.2% phosphite Irgafos 168 of Ciba, and 0.2% anti-UV Tinuvin 312 of Ciba), or 40% PA6.The composition may be, but is not limited to, those based on 10 (having Mn 30,000 and as otherwise defined), 40% PA6 (having Mn 28,000 and as otherwise defined), 20% impact modifier, ethylene / ethyl acrylate / anhydrous type (MFI6 at 190°C under 2.16 kg) in a weight ratio of 68.5 / 30 / 1.5, and 1.2% organic stabilizer (consisting of 0.8% phenol Lowinox 44B25 from Great Lakes, 0.2% phosphite Irgafos 168 from Ciba, and 0.2% anti-UV Tinuvin 312 from Ciba).

[0157] Regarding the barrier layer The term "barrier layer" refers to a layer that has low permeability and good resistance to hydrogen; in other words, the barrier layer slows down the passage of hydrogen into other layers of the structure, or even further out of the structure. The barrier layer, therefore, makes it possible to prevent, first and foremost, too much hydrogen from being lost into the atmosphere by diffusion, and thus make it possible to avoid explosion and combustion problems.

[0158] These barrier materials may be low-carbon polyamides, i.e., polyphthalamides having an average number of carbon atoms (C) per nitrogen atom (N) of less than 9, preferably semi-crystalline, and having a high melting point, and / or non-polyamide barrier materials, such as highly crystalline polymers, for example, copolymers of ethylene and vinyl alcohol (hereinafter referred to as EVOH), or further, functionalized fluorinated materials, such as functionalized polyvinylidene fluoride (PVDF), functionalized copolymers of ethylene and tetrafluoroethylene (ETFE), functionalized copolymers of ethylene, tetrafluoroethylene and hexafluoropropylene (EFEP), functionalized polyphenylene sulfide (PPS), and functionalized polybutylene naphthalate (PBN). If these polymers are not functionalized, an intermediate binder layer may then be added to obtain good adhesion within the MLT structure.

[0159] Of these barrier materials, those richest in EVOH, particularly vinyl alcohol comonomer, and those with improved impact resistance are particularly beneficial because they are less likely to produce fragile structures.

[0160] In other words, the term "barrier layer" means that the barrier layer is highly impermeable to hydrogen, and more specifically, that the hydrogen permeability at 23°C is less than 75 cc.mm / m2.24h.atm at 23°C under 0% relative humidity (RH).

[0161] Penetration is (cc.mm / m 2 It can also be expressed as 0.24hPa.

[0162] The permeability must then be 101,325 times greater.

[0163] Regarding the structure The multilayer structure thus includes a sealing layer and at least one composite reinforcing layer wrapped around the sealing layer, which may or may not be bonded to each other.

[0164] Advantageously, the sealing layer and the reinforcing layer do not adhere to each other and are composed of different polymers.

[0165] However, the aforementioned different polymers may be of the same type.

[0166] Therefore, since the sealing layer consists of a composition containing an aliphatic polyamide, the composite reinforcing layer then consists of a composition containing a different aliphatic polyamide than that of the sealing layer (for example, PA11 in the sealing layer and PA12 in the reinforcing layer, or vice versa), or the composite reinforcing layer consists of a composition containing a polyamide, such as a semi-aromatic polyamide, rather than an aliphatic one, so as to position a high Tg polymer as the matrix of the composite reinforcing.

[0167] In one embodiment, the sealing layer includes, from inside to outside, layer (a), optionally a binder layer, a barrier layer, optionally a binder layer, and layer (b).

[0168] The binder layers may be identical or different.

[0169] In one embodiment, the sealing layer includes, from inside to outside, layer (a), a barrier layer, a binder layer, and layer (b).

[0170] In one embodiment, the sealing layer includes, from inside to outside, layer (a), a binder layer, a barrier layer, optionally a binder layer and layer (b).

[0171] In one embodiment, the sealing layer includes, from inside to outside, layer (a), a binder layer, a barrier layer, and layer (b).

[0172] In one embodiment, the sealing layer includes, from inside to outside, layer (a), optionally a binder layer, a barrier layer, a binder layer, and layer (b).

[0173] In one embodiment, the sealing layer includes, from inside to outside, layer (a), a barrier layer, a binder layer, and layer (b).

[0174] In one embodiment, the sealing layer includes, from inside to outside, layer (a), a binder layer, a barrier layer, a binder layer, and layer (b).

[0175] The sealing layer may include one or more other layers made of thermoplastic polymer below layer (a), and one or more other layers made of thermoplastic polymer above layer (b).

[0176] In one embodiment, the sealing layer consists of layer (a), a barrier layer, a binder layer, and layer (b), arranged from the inside out.

[0177] In one embodiment, the sealing layer consists of, from inside to outside, layer (a), a binder layer, a barrier layer, and optionally a binder layer and layer (b).

[0178] In one embodiment, the sealing layer consists of layer (a), a binder layer, a barrier layer, and layer (b), arranged from the inside out.

[0179] In one embodiment, the sealing layer consists of, from inside to outside, layer (a), optionally a binder layer, a barrier layer, a binder layer, and layer (b).

[0180] In one embodiment, the sealing layer consists of layer (a), a barrier layer, a binder layer, and layer (b), arranged from the inside out.

[0181] In one embodiment, the sealing layer consists of layer (a), a binder layer, a barrier layer, a binder layer, and layer (b), arranged from the inside out.

[0182] The multilayer structure may include up to 10 composite reinforcing layers having different properties.

[0183] Advantageously, the multilayer structure includes 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 composite reinforcing layers.

[0184] Advantageously, the multilayer structure includes one, two, three, four, or five composite reinforcing layers.

[0185] Advantageously, the multilayer structure includes one, two, or three composite reinforcing layers.

[0186] Advantageously, these consist of compositions each containing the same polymer.

[0187] Advantageously, these consist of compositions each containing the same type of polymer.

[0188] Advantageously, these consist of compositions each containing a different polymer.

[0189] In one embodiment, the multilayer structure includes a sealing layer and several reinforcing layers, wherein the reinforcing layers adjacent to the sealing layer are wound around the sealing layer, and the other reinforcing layers are wound around directly adjacent reinforcing layers.

[0190] In one advantageous embodiment, the multilayer structure comprises a single sealing layer and a single composite reinforcing layer, the reinforcing layer being wound around the sealing layer.

[0191] Advantageously, in this latter embodiment, the polyamide of layer (a) and / or (b) is a short-chain aliphatic polyamide, specifically selected from PA6, PA66 and PA6 / 66, or a long-chain aliphatic polyamide, specifically selected from PA1010, PA1012, PA1212, PA11 and PA12, particularly PA11 and PA12, and the polymer P1j is an epoxy resin or epoxy-based resin.

[0192] Advantageously, in this latter embodiment, the polyamide of layers (a) and (b) is a short-chain aliphatic polyamide, specifically selected from PA6, PA66 and PA6 / 66, or a long-chain aliphatic polyamide, specifically selected from PA1010, PA1012, PA1212, PA11 and PA12, particularly PA11 and PA12, and the polymer P1j is an epoxy resin or epoxy-based resin.

[0193] Advantageously, in this latter embodiment, the polyamide of layer (a) is a short-chain aliphatic polyamide, specifically selected from PA6, PA66 and PA6 / 66, the polyamide of layer (b) is a long-chain aliphatic polyamide, specifically selected from PA1010, PA1012, PA1212, PA11 and PA12, particularly PA11 and PA12, and the polymer P1j is an epoxy resin or epoxy-based resin.

[0194] Advantageously, in this latter embodiment, the polyamide of layer (a) is a long-chain aliphatic polyamide, specifically selected from PA1010, PA1012, PA1212, PA11 and PA12, particularly PA11 and PA12; the polyamide of layer (b) is a short-chain aliphatic polyamide, specifically selected from PA6, PA66 and PA6 / 66; and the polymer P1j is an epoxy resin or epoxy-based resin.

[0195] Advantageously, in this latter embodiment, the polyamide of layer (a) and / or (b) is a short-chain aliphatic polyamide, specifically selected from PA6, PA66 and PA6 / 66, or a long-chain aliphatic polyamide, specifically selected from PA1010, PA1012, PA1212, PA11 and PA12, particularly PA11 and PA12, and the polymer P1j is a long-chain aliphatic polyamide, specifically selected from PA1010, PA1012, PA1212, PA11 and PA12, particularly PA11 and PA12, or a semi-aromatic polyamide, specifically selected from 11 / 5T, 11 / 6T, or 11 / 10T polyamides, MXDT / 10T, MPMDT / 10T and BACT / 10T.

[0196] Advantageously, in this latter embodiment, the polyamides of layers (a) and (b) are short-chain aliphatic polyamides, specifically selected from PA6, PA66 and PA6 / 66, or long-chain aliphatic polyamides, specifically selected from PA1010, PA1012, PA1212, PA11 and PA12, particularly PA11 and PA12, and the polymer P1j is a long-chain aliphatic polyamide, specifically selected from PA1010, PA1012, PA1212, PA11 and PA12, particularly PA11 and PA12, or semi-aromatic polyamides, specifically selected from 11 / 5T, 11 / 6T, or 11 / 10T polyamides, MXDT / 10T, MPMDT / 10T and BACT / 10T.

[0197] Advantageously, in this latter embodiment, the polyamide of layer (a) and / or (b) is a short-chain aliphatic polyamide, more specifically selected from PA6, PA66 and PA6 / 66, and the polymer P1j is a long-chain aliphatic polyamide, more specifically selected from PA1010, PA1012, PA1212, PA11 and PA12, particularly PA11 and PA12, or a semi-aromatic polyamide, more specifically selected from 11 / 5T, 11 / 6T, or 11 / 10T polyamides, MXDT / 10T, MPMDT / 10T and BACT / 10T.

[0198] Advantageously, in this latter embodiment, the polyamides of layers (a) and (b) are long-chain aliphatic polyamides, more specifically selected from PA1010, PA1012, PA1212, PA11 and PA12, particularly PA11 and PA12, and the polymer P1j is a long-chain aliphatic polyamide, more specifically selected from PA1010, PA1012, PA1212, PA11 and PA12, particularly PA11 and PA12, or a semi-aromatic polyamide, more specifically selected from 11 / 5T, 11 / 6T, or 11 / 10T polyamides, MXDT / 10T, MPMDT / 10T, and BACT / 10T.

[0199] Advantageously, in this latter embodiment, the polyamide of layer (a) is a short-chain aliphatic polyamide, specifically selected from PA6, PA66 and PA6 / 66; the polyamide of layer (b) is a long-chain aliphatic polyamide, specifically selected from PA1010, PA1012, PA1212, PA11 and PA12, particularly PA11 and PA12; the polymer P1j is a long-chain aliphatic polyamide, specifically selected from PA1010, PA1012, PA1212, PA11 and PA12, particularly PA11 and PA12; or a semi-aromatic polyamide, specifically selected from 11 / 5T, 11 / 6T, or 11 / 10T polyamides, MXDT / 10T, MPMDT / 10T and BACT / 10T.

[0200] Advantageously, in this latter embodiment, the polyamide of layer (a) is a long-chain aliphatic polyamide, specifically selected from PA1010, PA1012, PA1212, PA11 and PA12, particularly PA11 and PA12; the polyamide of layer (b) is a short-chain aliphatic polyamide, specifically selected from PA6, PA66 and PA6 / 66; the polymer P1j is a long-chain aliphatic polyamide, specifically selected from PA1010, PA1012, PA1212, PA11 and PA12, particularly PA11 and PA12; or a semi-aromatic polyamide, specifically selected from 11 / 5T, 11 / 6T, or 11 / 10T polyamides, MXDT / 10T, MPMDT / 10T, and BACT / 10T.

[0201] All combinations of these two types of layers are therefore within the scope of the present invention, provided that at least the innermost composite reinforcing layer is wrapped around the sealing layer, and the other layers are either bonded to each other or not.

[0202] Advantageously, in the multilayer structure, each reinforcing layer is composed of a polymer P1j of the same type, more specifically an epoxy resin or epoxy-based resin.

[0203] Advantageously, polyamide P1j is identical in all reinforcing layers.

[0204] 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.

[0205] The aforementioned outer layer is a second reinforcing layer, but it is permeable, which allows text to be placed on the structure.

[0206] Regarding fibrous materials The fibers that make up the aforementioned fibrous material are, in detail, inorganic, organic, or plant fibers.

[0207] Advantageously, the fibrous material may or may not be sized.

[0208] 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.

[0209] 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 matrix is ​​semi-crystalline, they have a Tg higher than the Tm of the polymer or thermoplastic polymer matrix 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 point Tm higher than the Tg of the polymer or thermoplastic polymer mixture constituting the pre-impregnation matrix, or if the thermoplastic polymer matrix mixture is semi-crystalline, they have a melting point Tm higher than the Tm of the polymer or thermoplastic polymer matrix 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.

[0210] The fibrous material may be cloth, string, or woven fabric made of fibers.

[0211] This could be considered equivalent to a fiber that uses a supporting thread.

[0212] 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.

[0213] 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.

[0214] Preferably, the fibrous material is selected from glass fibers, carbon fibers, basalt fibers or basalt-based fibers, or mixtures thereof, and more specifically from carbon fibers.

[0215] This is used in the form of one roving or several rovings.

[0216] In another aspect, the present invention relates to a method for producing the above-defined multilayer structure, characterized by comprising the step of preparing a sealing layer by extrusion blow molding, rotational molding, injection molding and / or extrusion.

[0217] In one embodiment, the method for generating a multilayer structure includes the step of filament winding a reinforcing layer defined above around a sealing layer defined above.

[0218] All the characteristics detailed above also apply to methods. [Examples]

[0219] [Example 1] The hydrogen permeability of PA11 liner and the liner of the present invention was tested at 23°C. The 2 mm sealing layer (liner) having five layers according to the present invention, which constitutes the tank of the present invention, was obtained by extrusion blow molding at a temperature suitable for the properties of the different thermoplastic resins used.

[0220] The liner has the following structure: PA11 / / binder / / EVOH / / binder / / PA11, each having a layer with the following thicknesses (900 μm / / 50 μm / / 100 μm / / 50 μm / / 900 μm).

[0221] PA11 is a polyamide 11 with a Mn (number-average molecular weight) of 45,000. Its melting point is 190°C, and its enthalpy of melting is 56 kJ / m³. 2 That is the case.

[0222] The binder is Tieflex S442 (registered trademark), sold by Arkema.

[0223] EVOH is an EVOH of the EVAL FP101B type (Eval) containing 32% ethylene.

[0224] When a composite reinforcement made of epoxy resin or epoxy-based resin is wound onto a liner, a wet filament winding method is then used, which involves winding fibers around the liner, these fibers having been previously pre-impregnated in a liquid epoxy bath or epoxy-based liquid bath. The reservoir is then polymerized in an oven for 2 hours.

[0225] The permeability of a liner made of PA11 and the liner of the present invention is measured according to a test, which involves flashing the upper surface of a film made of PA11 or consisting of five layers of the present invention with a test gas (hydrogen), and measuring the flow diffusing through the lower film by gas chromatography, with the vector gas being nitrogen.

[0226] The experimental conditions are presented in Table 1. TIFF2026076155000001.tif129170

[0227] The results are shown in Table 2, demonstrating that the liner of the present invention has much lower permeability than that of a liner made of PA11. TIFF2026076155000002.tif56170

[0228] Penetration is (cc.mm / m 2 It can also be expressed as 0.24hPa.

[0229] The permeability must then be 101,325 times greater.

Claims

1. A multilayer structure configured for transporting, distributing, and storing hydrogen, particularly for storing hydrogen, comprising a sealing layer (1) and at least one composite reinforcing layer (2) from the inside out. The aforementioned sealing layer is applied from the inside outwards. A layer (a) made of a composition, the composition is Short-chain aliphatic polyamide thermoplastic polymers whose Tm is measured according to ISO 11357-3:2013 and is above 160°C, specifically above 170°C. It mainly contains impact-resistant modifiers in amounts of more than 15% and up to 50%, or Long-chain semicrystalline aliphatic polyamide thermoplastic polymers whose Tm is measured according to ISO 11357-3:2013 and is above 160°C, specifically above 170°C. Impact modifiers up to 50% by weight, particularly impact modifiers up to less than 15% by weight, and more specifically, impact modifiers up to 12% by weight, relative to the total weight of the composition. Up to 3% by weight of plasticizer relative to the total weight of the composition. Layer (a) mainly contains A binder layer can be optionally selected. In particular, a hydrogen barrier layer made of a fluoropolymer, especially PVDF or EVOH, preferably EVOH. A binder layer can be optionally selected. A layer (b) comprising a composition, the composition is Short-chain aliphatic polyamide thermoplastic polymers whose Tm is measured according to ISO 11357-3:2013 and is above 160°C, specifically above 170°C. It mainly contains impact-resistant modifiers in amounts exceeding 15% and up to 50%, or Long-chain semicrystalline aliphatic polyamide thermoplastic polymers whose Tm is measured according to ISO 11357-3:2013 and is above 160°C, specifically above 170°C. Impact modifiers up to 50% by weight, particularly impact modifiers up to less than 15% by weight, and more specifically, impact modifiers up to 12% by weight, relative to the total weight of the composition. Up to 3% by weight of plasticizer relative to the total weight of the composition. Layer (b) mainly contains Includes, The innermost composite reinforcing layer (2) is wrapped around the sealing layer (1), 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 polymer P1j, where j = 1 to m, and m is the number of reinforcing layers, and more specifically comprises an epoxy resin or epoxy-based resin, in a multilayer structure.

2. The multilayer structure according to claim 1, characterized in that layer (a) and layer (b) contain the same polyamide.

3. The multilayer structure according to claim 1, characterized in that layer (a) and layer (b) contain different polyamides.

4. The multilayer structure according to any one of claims 1 to 3, characterized in that the polyamide of layer (a) and / or (b) is a long-chain aliphatic polyamide, more specifically selected from PA11, PA12, PA1010, PA1012, and in particular PA11 or PA12.

5. The multilayer structure according to any one of claims 1 to 3, characterized in that the polyamide of layer (a) and / or (b) is a short-chain aliphatic polyamide, and is more specifically selected from PA6, PA66 and PA6 / 66.

6. The multilayer structure according to any one of claims 1 to 5, characterized in that each reinforcing layer contains the same type of polymer, more specifically, an epoxy resin or epoxy-based resin.

7. A multilayer structure according to any one of claims 1 to 6, characterized by having a single reinforcing layer.

8. The multilayer structure according to any one of claims 1 to 6, characterized in that the polymer P1j is more specifically PA1010, PA1012, PA1212, PA11, and PA12.

9. The multilayer structure according to any one of claims 1 to 8, characterized in that the polymer P1j is an epoxy resin or an epoxy-based resin.

10. The multilayer structure according to any one of claims 1 to 9, characterized in that the multilayer structure comprises a single reinforcing layer and a sealing layer, the polyamide of layer (a) and / or (b) is a short-chain aliphatic polyamide, more specifically selected from PA6, PA66 and PA6 / 66, or a long-chain aliphatic polyamide, more specifically selected from PA1010, PA1012, PA1212, PA11 and PA12, particularly PA11 and PA12, and the polymer P1j is an epoxy resin or epoxy-based resin.

11. The multilayer structure according to any one of claims 1 to 9, characterized in that the multilayer structure comprises a single reinforcing layer and a sealing layer, the polyamide of layer (a) and / or (b) is a short-chain aliphatic polyamide, more specifically selected from PA6, PA66 and PA6 / 66, or a long-chain aliphatic polyamide, more specifically selected from PA1010, PA1012, PA1212, PA11 and PA12, particularly PA11 and PA12, and the polymer P1j is a long-chain aliphatic polyamide, more specifically selected from PA1010, PA1012, PA1212, PA11 and PA12, particularly PA11 and PA12, or a semi-aromatic polyamide, more specifically selected from 11 / 5T or 11 / 6T or 11 / 10T polyamide, 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, more particularly from 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, and the layer is the outermost layer of the multilayer structure.

14. A method for producing a multilayer structure according to any one of claims 1 to 13, comprising the step of preparing a sealing layer by extrusion blow molding, rotational molding, injection molding and / or extrusion.

15. A method for producing the multilayer structure according to claim 14, characterized by comprising the step of filament winding the reinforcing layer according to claim 1 around the sealing layer according to claim 1.

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