Multilayer structure for transporting or storing hydrogen

Abstract

The present invention relates to a multilayer structure for the transport, distribution and storage of hydrogen, in particular for the storage of hydrogen, comprising from the inside out a sealing layer (1) and at least one composite reinforcement layer (2), said sealing layer comprising from the inside out: a layer (a) consisting of a composition comprising mainly: a short-chain polyamide thermoplastic polymer, more than 15% and up to 50% by weight of an impact modifier, or mainly: a semi-crystalline long-chain polyamide thermoplastic polymer, up to 50% by weight of an impact modifier with respect to the total weight of the composition, up to 3% by weight of a plasticizer with respect to the total weight of the composition; optionally a binder layer; a hydrogen barrier layer, in particular made of a fluoropolymer, in particular PVDF, or EVOH; optionally a binder layer; a layer (b) consisting of a composition comprising mainly: a short-chain polyamide thermoplastic polymer, more than 15% and up to 50% by weight of an impact modifier, or mainly: a semi-crystalline long-chain polyamide thermoplastic polymer, up to 50% by weight of an impact modifier, up to 3% by weight of a plasticizer, said innermost composite reinforcement layer (2) being wound around said sealing layer (1) and at least one of said composite reinforcement layers consisting of a fibrous material in the form of continuous fibers impregnated with a composition comprising mainly at least one polymer P1j, j = 1 to m, m being the number of reinforcement layers.

Description

[Technical Field]

[0001] This patent application relates to the transportation (transportation), distribution, or storage of hydrogen, particularly to multilayer composite structures for the distribution or storage of hydrogen, and methods for manufacturing the same. [Background Technology]

[0002] Hydrogen tanks are currently attracting considerable attention from numerous manufacturers, particularly in the automotive industry. One goal is to develop vehicles that cause increasingly less pollution. Consequently, electric or hybrid vehicles, including batteries, are intended to gradually replace internal combustion engine vehicles such as gasoline or diesel cars. Batteries have proven to be relatively complex vehicle components. Depending on the battery's placement within the vehicle, protecting it from impacts and external environments with extreme temperatures and variable humidity is essential. Avoiding any risk of flame is also necessary.

[0003] Additionally, it is important that the operating temperature does not exceed 55°C to avoid damaging the battery cells and to maintain their lifespan. Conversely, for example, in winter, raising the battery temperature to optimize its operation may be necessary.

[0004] Moreover, electric vehicles still face several problems, namely battery range, the use of rare earth metals in these batteries, the fact that the resources used for them are not infinite, the recharging time being much longer than the time it takes to fill the tank, and the problem of electricity production in various countries to enable battery recharging.

[0005] Therefore, hydrogen is a viable alternative to electric batteries because it can be converted into electricity through fuel cells and thus power electric vehicles.

[0006] Hydrogen tanks often consist of a metal liner (or sealing layer) that must prevent hydrogen from leaking out. One type of tank, known as Type IV, is based on a thermoplastic liner wrapped around it with a composite material.

[0007] Their basic principle is to separate the two fundamental functions of sealing and mechanical strength and manage them independently. In this type of tank, a liner (or sealing jacket) made of thermoplastic resin is combined with a reinforcing structure made of fibers (glass, aramid, carbon), also known as a reinforcing jacket or layer, which allows operation at much higher pressures while reducing weight and avoiding the risk of explosive rupture in the event of a severe external attack.

[0008] Linings must have some basic characteristics:

[0009] The possibility of deformation (molding) through extrusion blow molding, rotational molding, injection molding or extrusion;

[0010] Low hydrogen permeability; in fact, the permeability of the lining is a key factor in limiting hydrogen loss from the tank.

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

[0012] Heat resistance at 120℃.

[0013] In practice, the following is necessary: ​​increase the filling speed of the hydrogen tank, which should be roughly equal to the filling speed of the fuel tank used for an internal combustion engine (about 3 to 5 minutes), but this increase in speed leads to a more significant heating of the tank, which then reaches a temperature of about 100°C.

[0014] The performance and safety of hydrogen tanks can be assessed using reference European laboratories (GasTeF: Hydrogen Tank Testing Facility), as described by Galasi et al. (World hydrogen energy conference 2012, Onboard compressed hydrogen storage: fast filing experiments and simulations, Energy Procedia 29, (2012) 192-200).

[0015] The first-generation Type IV tank used a lining based on high-density polyethylene (HDPE).

[0016] However, HDPE has the following drawbacks: it has a very low melting point and a high permeability to hydrogen, which raises new requirements for heat resistance and does not make it possible to increase the filling speed of the tank.

[0017] Liners based on polyamide PA6 have been developed for many years.

[0018] However, PA6 has the following disadvantages: it has low cold resistance.

[0019] US application 2014 / 008373 describes a lightweight storage cylinder for high-pressure compressed gases, the cylinder having a liner surrounded by a restraining layer, the liner comprising:

[0020] The first impact-modified polyamide (PA) inner layer in contact with the gas,

[0021] Thermoplastic outer layer in contact with the restraining layer; and

[0022] An adhesive bonding layer between the first impact-modified PA inner layer and the thermoplastic outer layer.

[0023] French application FR2923575 describes a tank for storing fluids under high pressure, which includes metal end members at each end along its axis, a liner surrounding the end members, and a structural layer of fibers impregnated with thermosetting resin surrounding the liner.

[0024] WO18155491 describes a hydrogen transport assembly with a three-layer structure, the inner layer of which is a composition consisting of PA11, 15 to 50% impact modifier, and 1 to 3% plasticizer, or none of the plasticizer, possessing hydrogen barrier properties, good flexibility, and durability at low temperatures. However, this structure is suitable for use in pipelines for transporting hydrogen but not for storing hydrogen.

[0025] Therefore, there remains a need to optimize the matrix of the composite to improve its mechanical strength at high temperatures, and to optimize the materials constituting the sealing sheath to improve its operating temperature. Consequently, any optional modifications to the composition of the materials constituting the sealing liner to be implemented must not result in a significant increase in the manufacturing temperature (extrusion blow molding, injection molding, rotational molding, etc.) of the liner compared to current practices.

[0026] These problems are addressed by providing a multilayer structure of the present invention intended for the transport, distribution or storage of hydrogen.

[0027] Throughout the instruction manual, the terms "lining" and "sealing sleeve" have the same meaning.

[0028] Therefore, the present invention relates to a multilayer structure intended for transporting, distributing and storing hydrogen, particularly for storing hydrogen, comprising, from the inside out, a sealing layer (1) and at least one composite reinforcing layer (2), the sealing layer comprising, from the inside out:

[0029] Layer (a) is composed of a composition, the composition mainly comprising:

[0030] Short-chain polyamide thermoplastic polymers, such as those with a Tm greater than 160°C, particularly greater than 170°C, as measured according to ISO 11357-3:2013,

[0031] Impact modifiers exceeding 15% and up to 50%,

[0032] Or mainly includes:

[0033] Long-chain semi-crystalline polyamide thermoplastic polymers, such as those with a Tm greater than 160°C, particularly greater than 170°C, as measured according to ISO 11357-3:2013.

[0034] The impact modifier accounts for up to 50% by weight of the total weight of the composition, particularly up to less than 15% by weight, and especially up to 12% by weight of the impact modifier.

[0035] Up to 3% by weight of plasticizer relative to the total weight of the composition;

[0036] Optional adhesive layer;

[0037] A hydrogen barrier layer, which is particularly made of a fluoropolymer, particularly PVDF, or EVOH, preferably EVOH;

[0038] Optional adhesive layer;

[0039] Layer (b) is composed of a composition that primarily comprises:

[0040] Short-chain polyamide thermoplastic polymers, such as those with a Tm greater than 160°C, particularly greater than 170°C, as measured according to ISO 11357-3:2013,

[0041] Impact modifiers exceeding 15% and up to 50%,

[0042] Or mainly includes:

[0043] Long-chain semi-crystalline polyamide thermoplastic polymers, such as those with a Tm greater than 160°C, particularly greater than 170°C, as measured according to ISO 11357-3:2013.

[0044] The impact modifier accounts for up to 50% by weight of the total weight of the composition, particularly up to less than 15% by weight, and especially up to 12% by weight of the impact modifier.

[0045] Plasticizer comprising up to 3% by weight relative to the total weight of the composition.

[0046] The innermost composite reinforcing layer (2) is wrapped around the sealing layer (1).

[0047] Furthermore, at least one of the composite reinforcing layers consists of a fibrous material in the form of continuous fibers impregnated with the composition, the composition mainly comprising at least one polymer P1j, particularly an epoxy resin or an epoxy-based resin, j = 1 to m, where m is the number of reinforcing layers.

[0048] PVDF corresponds to polyvinylidene fluoride.

[0049] EVOH corresponds to ethylene vinyl alcohol.

[0050] Advantageously, the Tm of short-chain polyamide thermoplastic polymers, as measured according to ISO 11357-3:2013, is greater than 200°C.

[0051] Therefore, the inventors unexpectedly discovered that using two heavily impact-modified short-chain semi-crystalline polyamide thermoplastic polymers, or long-chain semi-crystalline polyamide thermoplastic polymers including a limited proportion of impact modifiers and plasticizers, above or below the sealing layer, and using different polymers for the matrix of the composite, especially epoxy or epoxy-based resins (the composite is wrapped around the sealing layer), makes it possible to obtain a structure suitable for transporting, distributing, or storing hydrogen, and especially to increase the maximum operating temperature, which can be extended up to 120°C, thereby increasing the filling speed of the can.

[0052] "Multi-layer structure" should be understood to mean a tank comprising or consisting of: several layers, namely, a sealing layer comprising at least three layers and at least one reinforcing layer, particularly a single reinforcing layer.

[0053] Multi-layered structures are therefore understood to exclude pipes or tubes.

[0054] The tank can be a mobile storage tank for hydrogen on a truck used to transport hydrogen, on a car used to transport hydrogen and to supply hydrogen to fuel cells, such as on a train used to supply hydrogen or on a drone used to supply hydrogen, but it can also be a tank for static storage of hydrogen in a station used to distribute hydrogen to vehicles (vehicles).

[0055] In the first variant, the short-chain or long-chain polyamide thermoplastic polymer of layer (a) excludes polyether block amide (PEBA).

[0056] Polyether block amide (PEBA) is a copolymer having amide units (Ba1) and polyether units (Ba2), wherein the amide units (Ba1) correspond to aliphatic repeating units selected from: units obtained from at least one amino acid or units obtained from at least one lactam, or units XY obtained by polycondensation of:

[0057] - At least one diamine, said diamine preferably selected from linear or branched aliphatic diamines or mixtures thereof, and

[0058] - At least one carboxylic acid, wherein the carboxylic acid is preferably selected from:

[0059] Straight-chain or branched aliphatic diacids, or mixtures thereof,

[0060] The diamine and the diacid comprise 4 to 36 carbon atoms, advantageously 6 to 18 carbon atoms;

[0061] The polyether unit (Ba2) is particularly derived from at least one polyalkylene ether polyol, especially polyalkylene ether diol.

[0062] In the second variant, the composition of layer (a) does not contain a nucleating agent.

[0063] Nucleating agents are known to those skilled in the art, and the term refers to substances that, when introduced into a polymer, form nuclei for growing crystals in the molten polymer.

[0064] They can be selected from, for example, microtalc, carbon black, silica, titanium dioxide, and nanoclay.

[0065] 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) is free of nucleating agent.

[0066] In the fourth variant, the short-chain or long-chain polyamide thermoplastic polymer of layer (b) excludes polyether block amide (PEBA).

[0067] In the fifth variant, the composition of layer (b) does not contain a nucleating agent.

[0068] In the sixth variant, the short-chain or long-chain polyamide thermoplastic polymer of layer (b) excludes polyether block amide (PEBA) and the composition of layer (b) is free of nucleating agents.

[0069] In the seventh variant, the short-chain or long-chain polyamide thermoplastic polymers of layers (a) and (b) exclude polyether block amides (PEBA).

[0070] In the eighth variant, the composition of layers (a) and (b) does not contain a nucleating agent.

[0071] In the ninth variant, the short-chain or long-chain polyamide thermoplastic polymers of layers (a) and (b) exclude polyether block amides (PEBA), and the composition of layers (a) and (b) is free of nucleating agents.

[0072] In one embodiment, the multilayer structure comprises a sealing layer and a reinforcing layer.

[0073] Advantageously, the sealing layer (1) does not leak hydrogen at 23°C, that is, the hydrogen permeability at 23°C at 0% relative humidity (RH) is less than 500 cc.mm / m2.24h.atm.

[0074] In one embodiment, PA11 is excluded from the composition of layer (a).

[0075] In one embodiment, PA11 is excluded from the composition of layer (b).

[0076] In one embodiment, PA11 is excluded from the composition of layer (a) and the composition of layer (b).

[0077] The composite reinforcement layer (one or more) is wound around the sealing layer by, for example, a strip (or tape or roving) of polymer-impregnated fibers deposited via filament winding.

[0078] The polymers differ when several reinforcing layers are present.

[0079] When the polymer of the reinforcing layer is the same, several layers may exist, but it is advantageous to have a single reinforcing layer, which then has at least one complete wrap around the sealing layer.

[0080] This fully automated process, known to those skilled in the art, allows for the selection of winding angles layer by layer, which will provide the final structure with the ability to withstand internal pressure loads.

[0081] When there is only one sealing layer and one composite reinforcement layer, resulting in a double-layer multilayer structure (the sealing layer is considered a single layer), the two layers can adhere to each other and be in direct contact with each other, especially since the composite reinforcement layer is wrapped around the sealing layer.

[0082] When there are several composite reinforcement layers, the outermost layer (b) of the sealing layer and therefore the layer opposite to (opposite to) the layer in contact with hydrogen may or may not adhere to the innermost layer of the composite reinforcement layer.

[0083] Other composite reinforcement layers may or may not be adhered to each other.

[0084] Other sealing layers may or may not adhere to each other.

[0085] Advantageously, only one sealing layer and one reinforcing layer exist, and they do not adhere to each other.

[0086] Advantageously, only one sealing layer and one reinforcing layer exist and do not adhere to each other, and the reinforcing layer consists of a fibrous material in the form of continuous fibers impregnated with a composition mainly comprising at least one polymer P1j, particularly epoxy resin or epoxy resin.

[0087] In one embodiment, only one sealing layer and one reinforcing layer are present and do not adhere to each other, and the reinforcing layer consists of a fibrous material in the form of continuous fibers impregnated with a composition mainly comprising polymer P1j, wherein polymer P1j is an epoxy resin or an epoxy-based resin.

[0088] Throughout the specification, the term "epoxy group" means that the epoxy component comprises at least 50% by weight of the matrix.

[0089] Regarding the sealing layer and the thermoplastic polymers of layers (a) and (b)

[0090] Each of the layers (a) and (b) is composed primarily of a composition of at least one short-chain semi-crystalline polyamide thermoplastic polymer or a long-chain semi-crystalline polyamide thermoplastic polymer.

[0091] The term "short chain" refers to polyamides having 4 to less than 8, particularly 6 to less than 8, carbon atoms per nitrogen atom.

[0092] The term "long chain" means that the polyamide has a number of carbon atoms per nitrogen atom greater than or equal to 8, preferably greater than 9, and particularly greater than 10.

[0093] The term "major" means that the at least one polymer is present in more than 50% by weight relative to the total weight of the composition.

[0094] Advantageously, the at least one major polymer is present in more than 60% by weight, especially more than 70% by weight, particularly more than 80% by weight, and even more particularly greater than or equal to 90% by weight, relative to the total weight of the composition.

[0095] When the polyamide is long-chain, the composition of layer (a) may also include up to 50% by weight of impact modifier and / or up to 3% by weight of plasticizer and / or up to 5% by weight of additive relative to the total weight of the composition.

[0096] The additives may be selected from another polymer, antioxidants, heat stabilizers, UV absorbers, light stabilizers, lubricants, inorganic fillers, flame retardants, dyes, carbon black, and carbon nanofillers, excluding nucleating agents; in particular, the additives are selected from antioxidants, heat stabilizers, UV absorbers, light stabilizers, lubricants, inorganic fillers, flame retardants, dyes, carbon black, and carbon nanofillers, excluding nucleating agents.

[0097] The other polymers may be another semi-crystalline thermoplastic polymer or different polymers, especially EVOH (ethylene vinyl alcohol).

[0098] Advantageously, the composition of layer (a) comprises primarily the long-chain polyamide thermoplastic polymer, 0 to 50% by weight of an impact modifier, especially 0 to less than 15% by weight of an impact modifier, particularly 0 to 12% by weight of an impact modifier, 0 to 3% by weight of a plasticizer and 0 to 5% by weight of an additive, the sum of the components of the composition being equal to 100%.

[0099] Advantageously, the composition of layer (a) consists mainly of the long-chain polyamide thermoplastic polymer, 0 to 50% by weight of impact modifier, especially 0 to less than 15% by weight of impact modifier, particularly 0 to 12% by weight of impact modifier, 0 to 3% by weight of plasticizer and 0 to 5% by weight of additive, the sum of the components of the composition being equal to 100%.

[0100] In one embodiment, a single primary polymer is present in the sealing layer.

[0101] In one 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, especially 0.1 to 12% by weight, relative to the total weight of the composition.

[0102] In one embodiment, the composition of layer (a) does not contain plasticizers.

[0103] In 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, especially 0.1 to 12% by weight, and the composition of layer (a) is free of plasticizers relative to the total weight of the composition.

[0104] In 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, relative to the total weight of the composition.

[0105] When the polyamide is short-chain, the composition of layer (a) further includes an impact modifier of more than 15% by weight and up to 50% by weight relative to the total weight of the composition, and / or up to 3% by weight of plasticizer and / or up to 5% by weight of additive.

[0106] The additives may be selected from another polymer, antioxidants, heat stabilizers, UV absorbers, light stabilizers, lubricants, inorganic fillers, flame retardants, dyes, carbon black, and carbon nanofillers, excluding nucleating agents; in particular, the additives are selected from antioxidants, heat stabilizers, UV absorbers, light stabilizers, lubricants, inorganic fillers, flame retardants, dyes, carbon black, and carbon nanofillers, excluding nucleating agents.

[0107] The other polymers may be another semi-crystalline thermoplastic polymer or different polymers, especially EVOH (ethylene vinyl alcohol).

[0108] Advantageously, the composition of layer (a) comprises primarily the short-chain polyamide thermoplastic polymer, more than 15% to 50% by weight of an impact modifier, especially 20% to 50% by weight of an impact modifier, particularly 30% to 40% by weight of an impact modifier, 0% to 3% by weight of a plasticizer and 0% to 5% by weight of an additive, the sum of the components of the composition being equal to 100%.

[0109] Advantageously, the composition of layer (a) consists primarily of the short-chain polyamide thermoplastic polymer, more than 15% to 50% by weight of impact modifier, especially 20% to 50% by weight of impact modifier, 0% to 3% by weight of plasticizer and 0% to 5% by weight of additive, the sum of the components of the composition being equal to 100%.

[0110] In one embodiment, a single primary polymer is present in the sealing layer.

[0111] In one embodiment, the composition of layer (a) comprises more than 15% to 50% by weight of an impact modifier, particularly 20% to 50% by weight, relative to the total weight of the composition.

[0112] In one embodiment, the composition of layer (a) does not contain plasticizers.

[0113] In 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, especially 0.1 to 12% by weight, and the composition of layer (a) is free of plasticizers relative to the total weight of the composition.

[0114] In 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, relative to the total weight of the composition.

[0115] Regarding layer (b), it has the same properties as those described above for layer (a), whether for short-chain polyamides or long-chain polyamides.

[0116] The polyamide of layer (a) and the polyamide of layer (b) may be the same or different; in particular, they are the same.

[0117] Short-chain and long-chain semi-crystalline polyamide thermoplastic polymers

[0118] "Polyamide thermoplastic polymer" or "semi-crystalline polyamide thermoplastic polymer" refers to a material that is generally solid at ambient temperature, softens during temperature rise, particularly above its glass transition temperature (Tg), exhibits precise melting above its so-called melting point (Tm), and becomes solid again when the temperature drops below its crystallization temperature.

[0119] Tg, Tc, and Tm were determined by differential scanning calorimetry (DSC) according to standards 11357-2:2013 and 11357-3:2013, respectively.

[0120] The number-average molecular weight (Mn) of the semi-crystalline polyamide thermoplastic polymer is preferably in the range of 10,000 to 85,000, especially 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 greater than or equal to 0.8, as determined in m-cresol according to standard ISO 307:2007, but by changing the solvent (using m-cresol instead of sulfuric acid and at a temperature of 20°C).

[0121] The nomenclature used to define polyamides is described in ISO standard 1874-1:2011 “Plastiques–Matériaux polyamides (PA) pour moulage et extrusion–Partie 1:Désignation”, especially on page 3 (Tables 1 and 2) and is well known to those skilled in the art.

[0122] Polyamides can be homopolymers, copolymers, or mixtures thereof.

[0123] In one embodiment, the thermoplastic polymer is a long-chain aliphatic polyamide, i.e., a polyamide having an average number of carbon atoms per nitrogen atom greater than or equal to 8, preferably greater than 9, and particularly greater than 10.

[0124] Specifically, long-chain aliphatic polyamides are selected from:

[0125] Polyamide 11 (PA11), polyamide 12 (PA12), polyamide 1010 (PA1010), polyamide 1012 (PA1012), polyamide 1212 (PA1012), or mixtures thereof or copolyamides thereof, particularly PA11 and PA12.

[0126] More specifically, polyamide 11 (PA11), polyamide 12 (PA12), polyamide 1012 (PA1012), polyamide 1212 (PA1012), or mixtures thereof or their copolyamides, particularly PA11 and PA12.

[0127] In one embodiment, the long-chain aliphatic polyamide is selected from:

[0128] Polyamide 12 (PA12), polyamide 1010 (PA1010), polyamide 1012 (PA1012), polyamide 1212 (PA1012), or mixtures thereof or copolyamides thereof, particularly PA12.

[0129] In another embodiment, the long-chain aliphatic polyamide is selected from:

[0130] Polyamide 12 (PA12), polyamide 1012 (PA1012), polyamide 1212 (PA1012), or mixtures thereof or their copolyamides, particularly PA12.

[0131] In one embodiment, the thermoplastic polymer is a short-chain aliphatic polyamide, i.e., a polyamide having 4 to less than 8, particularly 6 to less than 8, carbon atoms per nitrogen atom.

[0132] Specifically, the short-chain aliphatic polyamides are selected from PA6, PA66, and PA6 / 66.

[0133] If welding is necessary, there are several methods that enable the welding of components made of polyamide thermoplastic polymers. Thus, contact or non-contact heating blades, ultrasonic, infrared, vibration, rotating one component against another, or even laser welding can be used.

[0134] Regarding impact modifiers

[0135] The impact modifier can be any impact modifier, as long as it is a polymer with a lower modulus than the resin and good adhesion to the matrix to dissipate cracking energy.

[0136] Impact modifiers are advantageously composed of polymers, particularly polyolefins, having a flexural modulus of less than 100 MPa as measured according to standard ISO 178 and a Tg of less than 0 °C (measured at the inflection point of a DSC temperature spectrum according to standard 11357-2).

[0137] In one implementation, PEBA is excluded from the definition of impact modifier.

[0138] The impact modifier may be a functionalized or non-functionalized polyolefin, or a mixture of at least one functionalized polyolefin and / or at least one non-functionalized polyolefin. For simplicity, the polyolefin is represented by (B), and functionalized polyolefins (B1) and non-functionalized polyolefins (B2) are described below.

[0139] Nonfunctionalized polyolefins (B2) are classically homopolymers or copolymers of α-olefins or dienes such as, for example, ethylene, propylene, 1-butene, 1-octene, and butadiene. As an example, the following may be mentioned:

[0140] - Homopolymers and copolymers of polyethylene, particularly LDPE, HDPE, LLDPE (linear low-density polyethylene), VLDPE (very low-density polyethylene) and metallocene polyethylene.

[0141] - Homopolymers or copolymers of propylene.

[0142] - Ethylene / α-olefin copolymers such as ethylene / propylene, EPR (an abbreviation for ethylene-propylene rubber) and ethylene / propylene / diene (ethylene propylene diene rubber) (EPDM).

[0143] - Styrene / ethylene-butene / styrene (SEBS), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), styrene / ethylene-propylene / styrene (SEPS) block copolymers.

[0144] - A copolymer of ethylene with at least one product selected from: salts or esters of unsaturated carboxylic acids such as alkyl methacrylates (e.g., methyl acrylate), or vinyl esters of saturated carboxylic acids such as vinyl acetate (EVA), wherein the proportion of comonomers may reach 40% by weight.

[0145] Functionalized polyolefins (B1) can be polymers of α-olefins having reactive units (functional groups); such reactive units are acids, anhydrides, or epoxy functional groups. As examples, the preceding polyolefin (B2) can be mentioned as being grafted or copolymerized or ternarily copolymerized by unsaturated epoxides such as glycidyl (meth)acrylate, or by carboxylic acids or corresponding salts or esters such as (meth)acrylic acid (which can be completely or partially neutralized by metals such as Zn), or even by carboxylic anhydrides such as maleic anhydride. Functionalized polyolefins are, for example, PE / EPR mixtures, whose weight ratios can vary widely, for example between 40 / 60 and 90 / 10, said mixtures being co-grafted with anhydrides, especially maleic anhydride, at a grafting rate of, for example, 0.01 to 5% by weight.

[0146] The functionalized polyolefin (B1) may be selected from the following (co)polymers grafted with maleic anhydride or glycidyl methacrylate, wherein the grafting rate is, for example, from 0.01 to 5% by weight:

[0147] -PE, PP, copolymers of ethylene with propylene, butene, hexene, or octene containing, for example, 35 to 80% by weight of ethylene;

[0148] 1) Ethylene / α-olefin copolymers such as ethylene / propylene, EPR (an abbreviation for ethylene-propylene rubber), and ethylene / propylene / diene (EPDM).

[0149] - Styrene / ethylene-butene / styrene (SEBS), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), styrene / ethylene-propylene / styrene (SEPS) block copolymers.

[0150] - A copolymer of ethylene and vinyl acetate (EVA) containing up to 40% by weight of vinyl acetate;

[0151] - Ethylene and (meth)acrylate copolymers containing up to 40% by weight of (meth)acrylate alkyl esters;

[0152] - A copolymer of ethylene with vinyl acetate (EVA) and alkyl (meth)acrylate containing up to 40% by weight of comonomers.

[0153] Functionalized polyolefins (B1) may also be selected from ethylene / propylene copolymers, wherein propylene, primarily grafted with maleic anhydride, is condensed with monoamine polyamides (or polyamide oligomers) (products described in EP-A-0,342,066).

[0154] Functionalized polyolefins (B1) may also be copolymers or terpolymers of at least the following units: (1) ethylene, (2) alkyl esters of (meth)acrylate or vinyl esters of saturated carboxylic acids, and (3) anhydrides such as maleic anhydride or (meth)acrylate or epoxy such as (meth)acrylate glycidyl ester.

[0155] As an example of the latter type of functionalized polyolefin, the following copolymers can be mentioned: wherein ethylene preferably accounts for at least 60% by weight of the copolymer and wherein the ternary comonomer (functional group) accounts for, for example, 0.1 to 10% by weight of the copolymer:

[0156] - Ethylene / (meth)acrylate alkyl ester / (meth)acrylic acid or maleic anhydride or glycidyl methacrylate copolymer;

[0157] - Ethylene / vinyl acetate / maleic anhydride or glycidyl methacrylate copolymer;

[0158] - Ethylene / vinyl acetate or (meth)acrylate alkyl ester / (meth)acrylic acid or maleic anhydride or glycidyl methacrylate copolymer.

[0159] In the aforementioned copolymers, Zn or Li can be used to salt (meth)acrylic acid.

[0160] The term “(meth)acrylate alkyl ester” in (B1) or (B2) means C1 to C8 alkyl methacrylate and C1 to C8 alkyl acrylate, and may be selected from methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, methyl methacrylate and ethyl methacrylate.

[0161] Furthermore, the polyolefins (B1) mentioned above can also be crosslinked by any suitable method or reagent (diepoxide, diacid, peroxide, etc.); the term functionalized polyolefin also includes the polyolefins mentioned above and mixtures of bifunctional reagents such as diacid, dianhydride, diepoxide, etc. that can react with these, or mixtures of at least two functionalized polyolefins that can react together.

[0162] The copolymers (B1) and (B2) mentioned above can be copolymerized in a statistical or sequential manner and have linear or branched structures.

[0163] The molecular weight, melt flow index (MFI), and density of these polyolefins can vary over a wide range, as those skilled in the art will know. MFI, an abbreviation for melt flow index, is a measure of fluidity in the molten state. It is measured according to the standard ASTM 1238.

[0164] Advantageously, the nonfunctionalized polyolefin (B2) is selected from homopolymers or copolymers of polypropylene and any ethylene homopolymer or copolymer of ethylene with higher α-olefin comonomers such as butene, hexene, octene, or 4-methyl-1-pentene. Examples of suitable polyolefins include PP, high-density PE, medium-density PE, linear low-density PE, low-density PE, and very low-density PE. These polyethylenes are known to those skilled in the art to be manufactured according to a "free radical" method, a "Ziegler" catalytic method, or more recently, a "metallocene" catalytic method.

[0165] Advantageously, the functionalized polyolefin (B1) is selected from any polymer comprising α-olefin units and units with polar reactive functional groups such as epoxy, carboxylic acid, or carboxylic anhydride functional groups. As examples of such polymers, terpolymers of ethylene, alkyl acrylates, and maleic anhydride or glycidyl methacrylate may be mentioned, for example, from the applicant's... Or via maleic anhydride-grafted polyolefins, such as those from the applicant. And terpolymers of ethylene, alkyl acrylates and (meth)acrylic acid. Homopolymers of polypropylene or copolymers of polypropylene grafted with carboxylic anhydride and then condensed with polyamide or monoamine polyamide oligomers may also be mentioned.

[0166] Advantageously, the composition constituting the sealing layer (one or more) does not contain polyether block amide (PEBA). In this embodiment, PEBA is therefore excluded from the impact modifier.

[0167] Advantageously, the transparent composition does not contain core-shell particles or core-shell polymers.

[0168] Core-shell particles must be understood as particles whose first layer forms the core and whose second or all subsequent layers form the corresponding shell.

[0169] Core-shell particles can be obtained by a process comprising at least two steps or several steps. Such methods are described, for example, in documents US2009 / 0149600 or EP0,722,961.

[0170] Regarding plasticizers:

[0171] The plasticizer may be a plasticizer commonly used in polyamide-based compositions (one or more).

[0172] Advantageously, a plasticizer with good thermal stability is used, which does not generate fumes during the steps of mixing different polymers and deforming the resulting composition.

[0173] Specifically, the plasticizer can be selected from:

[0174] Benzenesulfonamide derivatives, such as the ortho and para isomers of n-butylbenzenesulfonamide (BBSA), ethyl toluenesulfonamide (ETSA), N-cyclohexyl toluenesulfonamide, and N-(2-hydroxypropyl)benzenesulfonamide (HP-BSA),

[0175] Esters of hydroxybenzoic acid, such as 2-ethylhexyl p-hydroxybenzoate (EHPB) and 2-decyl hexyl p-hydroxybenzoate (HDPB),

[0176] Esters or ethers of tetrahydrofurfuryl alcohol, such as oligoethyleneoxytetrahydrofurfuryl alcohol, and

[0177] Esters of citric acid or hydroxymalonic acid, such as oligoethylene oxymalonic acid esters.

[0178] The preferred plasticizer is n-butylbenzenesulfonamide (BBSA).

[0179] Another more particularly preferred plasticizer is N-(2-hydroxypropyl)benzenesulfonamide (HP-BSA). In fact, the latter has the advantage of preventing the formation of deposits (“die drooling”) at the extruder screw and / or die during the deformation step of extrusion.

[0180] Of course, a mixture of plasticizers can be used.

[0181] Regarding the composite reinforcement layer and polymer P1j

[0182] Polymer P1j can be a thermoplastic polymer or a thermosetting polymer.

[0183] One or more composite reinforcement layers may exist.

[0184] Each of the layers is impregnated with a fibrous material in the form of a continuous fiber of the composition, the composition mainly comprising at least one thermoplastic polymer P1j, where j corresponds to the number of layers present.

[0185] j includes 1 to 10, especially 1 to 5, particularly 1 to 3, and preferably j = 1.

[0186] The term "major" means that the at least one polymer is present in more than 50% by weight relative to the total weight of the matrix of the composition and complex.

[0187] Advantageously, the at least one major polymer is present in more than 60% by weight, especially more than 70% by weight, particularly more than 80% by weight, and even more particularly greater than or equal to 90% by weight, relative to the total weight of the composition.

[0188] The composition may further include impact modifiers and / or additives.

[0189] Additives can be selected from antioxidants, heat stabilizers, UV absorbers, light stabilizers, lubricants, inorganic fillers, flame retardants, plasticizers, and dyes, except for nucleating agents.

[0190] Advantageously, the composition consists primarily of the thermoplastic polymer P1j, 0 to 15% by weight of an impact modifier, particularly 0 to 12% by weight of an impact modifier, and 0 to 5% by weight of an additive, the sum of the components of the composition being equal to 100 by weight.

[0191] The at least one main polymer in each layer may be the same or different.

[0192] In one embodiment, a single primary polymer is present at least in the composite reinforcement layer and does not adhere to the sealing layer.

[0193] In one embodiment, each reinforcing layer comprises the same type of polymer, particularly epoxy resin or epoxy-based resin.

[0194] Polymer P1j

[0195] Thermoplastic polymer P1j

[0196] Thermoplastic materials, or thermoplastic polymers, refer to materials that are generally solid at ambient temperature, can be semi-crystalline or amorphous, particularly semi-crystalline, and when amorphous they soften and flow at higher temperatures during temperature increases, particularly after exceeding their glass transition temperature (Tg), or when semi-crystalline they exhibit a rapid transformation above their so-called melting point (Tm), and become solid again when the temperature is lowered below their crystallization temperature Tc (for semi-crystalline) and below their glass transition temperature (for amorphous).

[0197] Tg, Tc, and Tm were determined by differential scanning calorimetry (DSC) according to standards 11357-2:2013 and 11357-3:2013, respectively.

[0198] The number-average molecular weight (Mn) of the thermoplastic polymer is preferably in the range of 10,000 to 40,000, more preferably 10,000 to 30,000. These Mn values ​​may correspond to an intrinsic viscosity greater than or equal to 0.8, as determined in m-cresol according to standard ISO 307:2007, but by changing the solvent (using m-cresol instead of sulfuric acid and at a temperature of 20°C).

[0199] As an example of a suitable semi-crystalline thermoplastic polymer in this invention, the following can be mentioned:

[0200] Polyamides, particularly those comprising aromatic and / or alicyclic structures, include copolymers such as polyamide-polyether copolymers.

[0201] Polyester,

[0202] Polyaryl ether ketone (PAEK),

[0203] Polyetheretherketone (PEEK)

[0204] Polyetherketoneketone (PEKK)

[0205] Polyetherketoneketone (PEKEKK)

[0206] Polyimides, particularly polyetherimides (PEI) or polyamide-imides,

[0207] Polysulfone (PSU), particularly polyarylsulfones such as polyphenylsulfone (PPSU),

[0208] Polyethersulfone (PES).

[0209] Semi-crystalline polymers, and especially polyamides and their semi-crystalline copolymers, are particularly preferred.

[0210] The nomenclature used to define polyamides is described in ISO standard 1874-1:2011 “Plastiques–Matériaux polyamides (PA) pour moulage et extrusion–Partie 1:Désignation”, particularly on page 3 (Tables 1 and 2) and is well known to those skilled in the art.

[0211] Polyamides can be homopolymers, copolymers, or mixtures thereof.

[0212] Advantageously, the semi-crystalline polyamide is a semi-aromatic polyamide, especially a semi-aromatic polyamide of formula X / YAr as described in EP1505099, particularly a semi-aromatic polyamide of formula A / XT, wherein A is selected from units obtained from amino acids, units obtained from lactams, and units corresponding to the formula (Ca diamine).(Cb diacid), wherein a represents the number of carbon atoms of the diamine and b represents the number of carbon atoms of the diacid, a and b are each between 4 and 36, advantageously between 9 and 18, 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;

[0213] XT represents a unit obtained by the polycondensation of Cx diamine and terephthalic acid, where x represents the number of carbon atoms in the Cx diamine, x being between 5 and 36, advantageously between 9 and 18, especially polyamides having the formula A / 5T, A / 6T, A / 9T, A / 10T, or A / 11T, where A is as defined above, and particularly polyamides selected from the following: PA MPMDT / 6T, PA11 / 10T, PA5T / 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 11 / MXDT / 10T, PA 11 / 5T / 10T.

[0214] T corresponds to terephthalic acid, MXD corresponds to m-phenylenediamine, MPMD corresponds to methylpentamethylenediamine, and BAC corresponds to bis(aminomethyl)cyclohexane. The semi-aromatic polyamides defined above particularly have a Tg greater than or equal to 80°C.

[0215] Thermosetting polymer P1j

[0216] The thermosetting polymer is selected from epoxy resins or epoxy-based resins, polyesters, vinyl esters and polyurethanes, or mixtures thereof, particularly epoxy resins or epoxy-based resins.

[0217] Advantageously, each composite reinforcing layer is composed of a composition comprising the same type of polymer, particularly epoxy resin or epoxy-based resin.

[0218] The composition comprising the polymer P1j is transparent to radiation suitable for welding.

[0219] In another embodiment, the composite reinforcement layer is wrapped around the sealing layer without any subsequent welding.

[0220] Regarding adhesives

[0221] The adhesive may be an adhesive composition as described in EP2098580, which comprises an adhesive composition including the following:

[0222] - At least one polyamide having an average number of carbon atoms per nitrogen atom, expressed as CA, between 4 and 8.5, advantageously between 4 and 7;

[0223] - At least one polyamide having a melting point greater than or equal to 180°C and an average number of carbon atoms per nitrogen atom, expressed as CB, between 7 and 10, advantageously between 7.5 and 9.5;

[0224] - At least one polyamide having an average number of carbon atoms per nitrogen atom, expressed as C, between 9 and 18, advantageously between 10 and 18;

[0225] At least 50% by weight of the composition is formed from one or more polyamides selected from polyamides A, B, and C.

[0226] The mass-weighted average melting enthalpy of these polyamides in the composition is greater than 25 J / g (DSC).

[0227] The average number of carbon atoms per nitrogen atom in polyamides A, B, and C further satisfies the following strict inequality: CA <CB<CC。

[0228] The binder may also be, for example, but not limited to, the following: a composition based on 50% of copolyamide 6 / 12 having 16,000 Mn (in a 70 / 30 ratio by weight) and 50% of copolyamide 6 / 12 having 16,000 Mn (in a 70 / 30 ratio by weight); a composition based on PP (polypropylene) grafted with maleic anhydride, known from Mitsui under the name Admer QF551A; a composition based on PA610 (having 30,000 Mn, and as otherwise defined) and 36% of PA6 (having 28,000 Mn) and 1.2% of an organic stabilizer (composed of 0.8% of phenolic Lowinox 44B25 from Great Lakes, 0.2% of phosphite Irgafos 168 from Ciba, and 0.2% of UV-resistant Tinuvin from Ciba). Compositions based on PA612 (having 29,000 Mn, and as otherwise defined) and 36% PA6 (having 28,000 Mn, and as otherwise defined) and 1.2% organic stabilizers (composed of 0.8% phenolic Lowinox 44B25 from Great Lakes, 0.2% phosphite Irgafos 168 from Ciba, and 0.2% UV-resistant Tinuvin 312 from Ciba); compositions based on PA610 (having 30,000 Mn, and as otherwise defined) and 36% PA12 (having 35,000 Mn, and as otherwise defined) and 1.2% organic stabilizers (composed of 0.8% phenolic Lowinox 44B25 from Great Lakes, and 0.2% phosphite Irgafos from Ciba). The composition comprises 168 and 0.2% of Tinuvin 312, an anti-UV compound from Ciba; based on 40% PA6 (with 28,000 Mn, and as otherwise defined), 40% PA12 (with 35,000 Mn, and as otherwise defined), 20% functionalized EPR Exxelor VA1801 (from Exxon), and 1.2% organic stabilizer (composed of 0.8% Lowinox 44B25 phenol from Great Lakes, 0.2% Irgafos 168 phosphite from Ciba, and 0.2% Tinuvin 312, an anti-UV compound from Ciba). Composition of 312; or based on 40% PA6.10 (having 30,000 Mn, and as otherwise defined), 40% PA6 (having 28,000 Mn, and as otherwise defined), and 20% by weight of an ethylene / ethyl acrylate / anhydride type impact modifier (MFI of 6 at 190°C at 2.16 kg), and 1.2% organic stabilizer (from 0.The composition consists of 8% Lowinox 44B25 (phenol from Great Lakes), 0.2% Irgafos 168 (phosphite from Ciba), and 0.2% Tinuvin 312 (UV-resistant from Ciba).

[0229] Regarding the barrier layer

[0230] The term "barrier layer" refers to a layer with low permeability and good resistance to hydrogen gas. In other words, the barrier layer slows down the flow of hydrogen into other layers of a structure or even to the outside of the structure. Therefore, the barrier layer is primarily designed to prevent excessive hydrogen loss into the atmosphere through diffusion, thereby avoiding explosion and combustion problems.

[0231] These barrier materials can be: low-carbon polyamides, i.e., in which the average number of carbon atoms (C) relative to nitrogen atoms (N) is less than 9, preferably semi-crystalline and having a high melting point; polyphthalamides and / or non-polyamide barrier materials such as highly crystalline polymers such as copolymers of ethylene and vinyl alcohol (hereinafter referred to as EVOH); or even 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 can be added to provide good adhesion within the MLT structure.

[0232] Among these barrier materials, EVOH is particularly beneficial, especially those richest in vinyl alcohol comonomers and those modified for impact resistance, because they enable the manufacture of less brittle structures.

[0233] In other words, the term "barrier layer" means that the barrier layer is highly impermeable to hydrogen; specifically, at 23°C and 0% relative humidity (RH), the permeability to hydrogen is less than 75 cc.mm / m2.24h.atm.

[0234] Permeability is also acceptable (cc.mm / m) 2 .24h.Pa) indicates.

[0235] Then the penetration rate must be multiplied by 101325.

[0236] About the structure

[0237] The multilayer structure therefore includes a sealing layer and at least one composite reinforcing layer wrapped around the sealing layer and which may or may not adhere to each other.

[0238] Advantageously, the sealing layer and the reinforcing layer do not adhere to each other and are composed of compositions comprising different polymers respectively.

[0239] However, the different polymers can be of the same type.

[0240] Therefore, since the sealing layer is composed of a composition including aliphatic polyamides, the composite reinforcement layer is composed of a composition including aliphatic polyamides different from those in the sealing layer (e.g., PA11 for the sealing layer and PA12 for the reinforcement layer, or vice versa), or the composite reinforcement layer is composed of a composition including a non-aliphatic polyamide and, for example, a semi-aromatic polyamide, to accommodate a high Tg polymer as the matrix of the composite reinforcement.

[0241] In one embodiment, the sealing layer comprises, from the inside out: layer (a), optionally an adhesive layer, a barrier layer, optionally an adhesive layer, and layer (b).

[0242] Multiple layers of adhesive can be the same or different.

[0243] In one embodiment, the sealing layer comprises, from the inside out: layer (a), a barrier layer, an adhesive layer, and layer (b).

[0244] In one embodiment, the sealing layer comprises, from the inside out: layer (a), an adhesive layer, a barrier layer, optionally an adhesive layer, and layer (b).

[0245] In one embodiment, the sealing layer comprises, from the inside out: layer (a), an adhesive layer, a barrier layer, and layer (b).

[0246] In one embodiment, the sealing layer comprises, from the inside out: layer (a), optionally an adhesive layer, a barrier layer, an adhesive layer, and layer (b).

[0247] In one embodiment, the sealing layer comprises, from the inside out: layer (a), a barrier layer, an adhesive layer, and layer (b).

[0248] In one embodiment, the sealing layer comprises, from the inside out: layer (a), an adhesive layer, a barrier layer, an adhesive layer, and layer (b).

[0249] The sealing layer may include one or more additional layers of thermoplastic polymer below layer (a) and one or more additional layers of thermoplastic polymer above layer (b).

[0250] In one embodiment, the sealing layer comprises, from the inside out, the following: layer (a), barrier layer, adhesive layer, and layer (b).

[0251] In one embodiment, the sealing layer comprises, from the inside out, the following: layer (a), an adhesive layer, a barrier layer, optionally an adhesive layer, and layer (b).

[0252] In one embodiment, the sealing layer comprises, from the inside out, the following: layer (a), adhesive layer, barrier layer, and layer (b).

[0253] In one embodiment, the sealing layer comprises, from the inside out, the following: layer (a), optionally an adhesive layer, a barrier layer, another adhesive layer, and layer (b).

[0254] In one embodiment, the sealing layer comprises, from the inside out, the following: layer (a), barrier layer, adhesive layer, and layer (b).

[0255] In one embodiment, the sealing layer comprises, from the inside out, the following: layer (a), adhesive layer, barrier layer, adhesive layer, and layer (b).

[0256] The multilayer structure may include up to 10 composite reinforcement layers with different properties.

[0257] Advantageously, the multilayer structure includes one, two, three, four, five, six, seven, eight, nine, or ten composite reinforcement layers.

[0258] Advantageously, the multilayer structure includes one, two, three, four, or five composite reinforcement layers.

[0259] Advantageously, the multilayer structure includes one, two, or three composite reinforcement layers.

[0260] Advantageously, they consist of compositions that each comprise the same polymer.

[0261] Advantageously, they consist of compositions that each comprise the same type of polymer.

[0262] Advantageously, they consist of compositions comprising different polymers.

[0263] In one embodiment, the multilayer structure includes a sealing layer and a plurality of 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 the directly adjacent reinforcing layers.

[0264] In one advantageous embodiment, the multilayer structure includes a single sealing layer and a single composite reinforcement layer, the reinforcement layer being wound around the sealing layer.

[0265] Advantageously, in this latter embodiment, the polyamide of layer (a) and / or (b) is: a short-chain aliphatic polyamide, particularly selected from PA6, PA66 and PA6 / 66; or a long-chain aliphatic polyamide, particularly selected from PA1010, PA1012, PA1212, PA11 and PA12, especially PA11 and PA12, and the polymer P1j is a resin or an epoxy resin.

[0266] Advantageously, in this latter embodiment, the polyamide of layers (a) and (b) is: a short-chain aliphatic polyamide, particularly selected from PA6, PA66 and PA6 / 66; or a long-chain aliphatic polyamide, particularly selected from PA1010, PA1012, PA1212, PA11 and PA12, especially PA11 and PA12, and the polymer P1j is a resin or an epoxy resin.

[0267] Advantageously, in this latter embodiment, the polyamide of layer (a) is a short-chain aliphatic polyamide, particularly selected from PA6, PA66 and PA6 / 66, and the polyamide of layer (b) is a long-chain aliphatic polyamide, particularly selected from PA1010, PA1012, PA1212, PA11 and PA12, especially PA11 and PA12, and the polymer P1j is a resin or an epoxy resin.

[0268] Advantageously, in this latter embodiment, the polyamide of layer (a) is a long-chain aliphatic polyamide, particularly selected from PA1010, PA1012, PA1212, PA11 and PA12, especially PA11 and PA12, and the polyamide of layer (b) is a short-chain aliphatic polyamide, particularly selected from PA6, PA66 and PA6 / 66, and the polymer P1j is a resin or epoxy resin.

[0269] Advantageously, in this latter embodiment, the polyamide of layer (a) and / or (b) is: a short-chain aliphatic polyamide, particularly selected from PA6, PA66 and PA6 / 66; or a long-chain aliphatic polyamide, particularly selected from PA1010, PA1012, PA1212, PA11 and PA12, especially PA11 and PA12, and the polymer P1j is a long-chain aliphatic polyamide, particularly selected from PA1010, PA1012, PA1212, PA11 and PA12, especially PA11 and PA12; or a semi-aromatic polyamide, particularly selected from 11 / 5T or 11 / 6T or 11 / 10T polyamide, MXDT / 10T, MPMDT / 10T and BACT / 10T.

[0270] Advantageously, in this latter embodiment, the polyamide of layer (a) and (b) are: short-chain aliphatic polyamides, particularly selected from PA6, PA66 and PA6 / 66; or long-chain aliphatic polyamides, particularly selected from PA1010, PA1012, PA1212, PA11 and PA12, especially PA11 and PA12, and the polymer P1j is a long-chain aliphatic polyamide, particularly selected from PA1010, PA1012, PA1212, PA11 and PA12, especially PA11 and PA12; or semi-aromatic polyamides, particularly selected from 11 / 5T or 11 / 6T or 11 / 10T polyamides, MXDT / 10T, MPMDT / 10T and BACT / 10T.

[0271] Advantageously, in this latter embodiment, the polyamide of layer (a) and / or (b) is a short-chain aliphatic polyamide, particularly selected from PA6, PA66 and PA6 / 66, and the polymer P1j is a long-chain aliphatic polyamide, particularly selected from PA1010, PA1012, PA1212, PA11 and PA12, especially PA11 and PA12; or a semi-aromatic polyamide, particularly selected from 11 / 5T or 11 / 6T or 11 / 10T polyamide, MXDT / 10T, MPMDT / 10T and BACT / 10T.

[0272] Advantageously, in this latter embodiment, the polyamide of layers (a) and (b) is a long-chain aliphatic polyamide, particularly selected from PA1010, PA1012, PA1212, PA11 and PA12, especially PA11 and PA12, and the polymer P1j is a long-chain aliphatic polyamide, particularly selected from PA1010, PA1012, PA1212, PA11 and PA12, especially PA11 and PA12; or a semi-aromatic polyamide, particularly selected from 11 / 5T or 11 / 6T or 11 / 10T polyamide, MXDT / 10T, MPMDT / 10T and BACT / 10T.

[0273] Advantageously, in this latter embodiment, the polyamide of layer (a) is a short-chain aliphatic polyamide, particularly selected from PA6, PA66 and PA6 / 66, and the polyamide of layer (b) is a long-chain aliphatic polyamide, particularly selected from PA1010, PA1012, PA1212, PA11 and PA12, especially PA11 and PA12, and the polymer P1j is a long-chain aliphatic polyamide, particularly selected from PA1010, PA1012, PA1212, PA11 and PA12, especially PA11 and PA12; or a semi-aromatic polyamide, particularly selected from 11 / 5T or 11 / 6T or 11 / 10T polyamide, MXDT / 10T, MPMDT / 10T and BACT / 10T.

[0274] Advantageously, in this latter embodiment, the polyamide of layer (a) is a long-chain aliphatic polyamide, particularly selected from PA1010, PA1012, PA1212, PA11 and PA12, especially PA11 and PA12, and the polyamide of layer (b) is a short-chain aliphatic polyamide, particularly selected from PA6, PA66 and PA6 / 66, and the polymer P1j is a long-chain aliphatic polyamide, particularly selected from PA1010, PA1012, PA1212, PA11 and PA12, especially PA11 and PA12; or a semi-aromatic polyamide, particularly selected from 11 / 5T or 11 / 6T or 11 / 10T polyamide, MXDT / 10T, MPMDT / 10T and BACT / 10T.

[0275] All combinations of these two layers are therefore within the scope of the invention, provided that at least the innermost composite reinforcing layer is wrapped around the sealing layer, and the other layers are either adhered to each other or not.

[0276] Advantageously, in the multilayer structure, each reinforcing layer is composed of a composition comprising the same type of polymer P1j, particularly epoxy resin or epoxy-based resin.

[0277] Advantageously, polyamide P1j is the same for all reinforcing layers.

[0278] Advantageously, the multilayer structure further includes at least one outer layer consisting of a fibrous material made of continuous glass fibers impregnated with a transparent amorphous polymer, the outermost layer of the multilayer structure.

[0279] The outer layer is a second enhancement layer, but it is transparent, which makes it possible to set text on the structure.

[0280] Regarding fiber materials

[0281] The fibers constituting the fibrous material are, in particular, mineral, organic, or plant fibers.

[0282] Advantageously, the fiber material may be sized or unsized.

[0283] The fibrous material may therefore include up to 3.5% by weight of organic material (thermosetting or thermoplastic resin type), referred to as sizing.

[0284] Mineral fibers include, for example, carbon fibers, glass fibers, basalt or basalt-based fibers, silica fibers, or silicon carbide fibers. Organic fibers include, for example, thermoplastic or thermosetting polymer-based fibers, such as semi-aromatic polyamide fibers, aromatic polyamide fibers, or polyolefin fibers. Preferably, they are based on amorphous thermoplastic polymers and have a higher glass transition temperature Tg than the latter when the polymer or thermoplastic polymer mixture constituting the preimpregnated matrix is ​​amorphous, or a higher glass transition temperature Tm than the latter when the polymer or thermoplastic polymer matrix constituting the preimpregnated matrix is ​​semi-crystalline. Advantageously, they are based on semi-crystalline thermoplastic polymers and have a higher melting point Tm than the latter when the polymer or thermoplastic polymer mixture constituting the preimpregnated matrix is ​​amorphous, or a higher melting point Tm than the latter when the polymer or thermoplastic polymer matrix mixture constituting the preimpregnated matrix is ​​semi-crystalline. Therefore, the organic fibers constituting the fibrous material do not pose a risk of melting during impregnation with the thermoplastic matrix of the final composite. Plant fibers include natural flax, hemp, lignin, bamboo, silk, especially spider silk, sisal, and other cellulose fibers, especially viscose. These plant fibers can be used virgin, treated, or coated to promote adhesion and impregnation with the thermoplastic polymer matrix.

[0285] Fiber materials can also be fabrics woven or spun from fibers.

[0286] It can also correspond to fibers with support lines.

[0287] These constituent fibers can be used alone or in mixtures. Thus, organic fibers can be mixed with mineral fibers to preimpregnate with thermoplastic polymer powder and to form preimpregnated fibrous materials.

[0288] Organic fiber bundles (strands) may have a certain weight. They may further have several geometries. The constituent fibers of the fibrous material may further take the form of a mixture of these reinforcing fibers with different geometries. The fibers are continuous fibers.

[0289] Preferably, the fiber material is selected from glass fiber, carbon fiber, basalt fiber or basalt-based fiber, or mixtures thereof, particularly carbon fiber.

[0290] It is used in the form of a single roving or several rovings.

[0291] According to another aspect, the present invention relates to a method for manufacturing a multilayer structure as defined above, characterized in that it includes the step of preparing a sealing layer by extrusion blow molding, rotational molding, injection molding and / or extrusion.

[0292] In one embodiment, the method for manufacturing a multilayer structure includes winding reinforcing filaments as defined above around a sealing layer as defined above.

[0293] All the characteristics detailed above also apply to the method described above. [Example]

[0294] Example 1: Testing the hydrogen permeability of PA11 lining and the lining of the present invention at 23°C.

[0295] The 2mm sealing layer (lining) of the can of the present invention, which has five layers, is obtained by extrusion blow molding at a temperature suitable for the properties of the different thermoplastic resins used.

[0296] The lining has the following structure:

[0297] PA11 / / Adhesive / / ​​EVOH / / Adhesive / / ​​PA11, the layer having the following corresponding thicknesses: (900μm / / 50μm / / 100μm / / 50μm / / 900μm).

[0298] PA11 is a polyamide 11 with a number-average molecular weight of 45,000 Mn. Its melting point is 190°C; its enthalpy of fusion is 56 kJ / m³. 2 .

[0299] The adhesive is Tieflex, sold by Arkema.

[0300] EVOH is EVAL FP101B type (from Eval) containing 32% ethylene.

[0301] If a composite reinforcement made of epoxy or epoxy resin is wound onto the lining, a wet-winding process is used. This process involves winding fibers around the lining, the fibers having been pre-impregnated in a bath of liquid epoxy or epoxy liquid. The mixture is then polymerized in an oven for 2 hours.

[0302] The permeability of the lining made of PA11 and the lining of the present invention was measured according to the following test: the test consisted of flushing the upper surface of the membrane made of PA11 or the five-layer membrane of the present invention with a test gas (hydrogen), and measuring the flow rate through the membrane in the lower portion flushed with carrier gas nitrogen by gas chromatography.

[0303] The experimental conditions are shown in Table 1:

[0304] [Table 1]

[0305]

[0306]

[0307] The results are shown in Table 2 and show that the lining of the present invention has a much lower permeability than the lining made of PA11.

[0308] [Table 2]

[0309]

[0310] The permeability can also be (cc.mm / m) 2 .24h.Pa) indicates.

[0311] The permeability must then be multiplied by 101325.

Claims

1. Multilayer structure intended for the transport, distribution and storage of hydrogen, comprising from the inside out a sealing layer (1) and at least one composite reinforcement layer (2), said sealing layer comprising from the inside out: a layer (a) consisting of a composition comprising mainly: a short-chain aliphatic polyamide thermoplastic polymer having a Tm greater than 160°C measured according to ISO 11357-3: 2013, more than 15% and up to 50% of an impact modifier, or mainly comprising: a long-chain semi-crystalline aliphatic polyamide thermoplastic polymer having a Tm greater than 160°C measured according to ISO 11357-3: 2013, up to 50% by weight of an impact modifier with respect to the total weight of the composition, up to 3% by weight of a plasticizer with respect to the total weight of the composition; optionally a tie layer; a hydrogen barrier layer; optionally a tie layer; a layer (b) consisting of a composition comprising mainly: a short-chain aliphatic polyamide thermoplastic polymer having a Tm greater than 160°C measured according to ISO 11357-3: 2013, more than 15% and up to 50% of an impact modifier, or mainly comprising: a long-chain semi-crystalline aliphatic polyamide thermoplastic polymer having a Tm greater than 160°C measured according to ISO 11357-3: 2013, up to 50% by weight of an impact modifier with respect to the total weight of the composition, up to 3% by weight of a plasticizer with respect to the total weight of the composition, said innermost composite reinforcement layer (2) being wound around said sealing layer (1), and at least one of said composite reinforcement layers consisting of a fibrous material in the form of continuous fibers impregnated with a composition comprising mainly at least one polymer P1j, j = 1 to m, m being the number of reinforcement layers.

2. Multilayer structure according to claim 1, characterized in that it is intended for the storage of hydrogen.

3. The multilayer structure according to claim 1, characterized in that said layer (a) consists of a composition comprising essentially: a short-chain aliphatic polyamide thermoplastic polymer having a Tm greater than 170°C.

4. The multilayer structure according to claim 1, characterized in that said layer (a) consists of a composition comprising essentially: a long-chain semi-crystalline aliphatic polyamide thermoplastic polymer having a Tm greater than 170°C.

5. The multilayer structure according to claim 1, characterized in that said layer (a) consists of a composition comprising essentially: up to 15% by weight of an impact modifier.

6. The multilayer structure according to claim 5, characterized in that said layer (a) consists of a composition comprising essentially: up to 12% by weight of an impact modifier.

7. Multilayer structure according to claim 1, characterized in that the hydrogen barrier layer is made of a fluoropolymer or EVOH.

8. Multilayer structure according to claim 7, characterized in that the hydrogen barrier layer is made of PVDF.

9. Multilayer structure according to claim 7, characterized in that the hydrogen barrier layer is made of EVOH.

10. The multilayer structure according to claim 1, characterized in that layer (b) consists of a composition comprising essentially: a short-chain aliphatic polyamide thermoplastic polymer having a Tm greater than 170°C.

11. The multilayer structure according to claim 1, characterized in that layer (b) consists of a composition comprising essentially: a long-chain semi-crystalline aliphatic polyamide thermoplastic polymer having a Tm greater than 170°C.

12. The multilayer structure according to claim 1, characterized in that layer (b) consists of a composition comprising essentially: up to 15% by weight of an impact modifier.

13. The multilayer structure according to claim 12, characterized in that layer (b) consists of a composition comprising essentially: up to 12% by weight of an impact modifier.

14. Multilayer structure according to claim 1, characterized in that at least one of said composite reinforcement layers consists of a fibrous material in the form of continuous fibers impregnated with a composition comprising mainly an epoxy resin or an epoxy-based resin.

15. Multilayer structure according to claim 1, characterized in that said layer (a) and said layer (b) comprise the same polyamide.

16. Multilayer structure according to claim 1, characterized in that said layer (a) and said layer (b) comprise different polyamides.

17. Multilayer structure according to one of claims 1 to 16, characterized in that the polyamide of layer (a) and / or (b) is a long-chain aliphatic polyamide.

18. Multilayer structure according to claim 17, characterized in that the polyamide of layer (a) and / or (b) is a long-chain aliphatic polyamide selected from the group consisting of PA 11, PA 12, PA 1010, PA 1012.

19. Multilayer structure according to claim 17, characterized in that the polyamide of layer (a) and / or (b) is a long-chain aliphatic polyamide selected from the group consisting of PA 11 or PA 12.

20. Multilayer structure according to any one of claims 1 to 16, characterized in that the polyamide of layer (a) and / or (b) is a short-chain aliphatic polyamide.

21. Multilayer structure according to claim 20, characterized in that the polyamide of layer (a) and / or (b) is a short-chain aliphatic polyamide selected from the group consisting of PA 6, PA 66 and PA 6 / 66.

22. Multilayer structure according to any one of claims 1 to 16, characterized in that each reinforcing layer comprises the same type of polymer.

23. Multilayer structure according to claim 22, characterized in that each reinforcing layer comprises an epoxy resin or epoxy-based resin.

24. Multilayer structure according to any one of claims 1 to 16, characterized in that it has a single reinforcing layer.

25. Multilayer structure according to any one of claims 1 to 16, characterized in that said polymer P1j is selected from the group consisting of PA 1010, PA 1012, PA 1212, PA 11, PA 12.

26. Multilayer structure according to any one of claims 1 to 16, characterized in that said polymer P1j is an epoxy resin or epoxy-based resin.

27. Multilayer structure according to any one of claims 1 to 16, characterized in that it consists of a single reinforcing layer and a sealing layer, in which said polyamide of layer (a) and / or (b) is a short-chain aliphatic polyamide; or a long-chain aliphatic polyamide and said polymer P1j is an epoxy resin or epoxy-based resin.

28. Multilayer structure according to claim 27, characterized in that said polyamide of layer (a) and / or (b) is a short-chain aliphatic polyamide selected from the group consisting of PA 6, PA 66 and PA 6 / 66.

29. Multilayer structure according to claim 27, characterized in that said polyamide of layer (a) and / or (b) is a long-chain aliphatic polyamide selected from the group consisting of PA 1010, PA 1012, PA 1212, PA 11 and PA 12.

30. Multilayer structure according to claim 29, characterized in that said polyamide of layer (a) and / or (b) is a long-chain aliphatic polyamide selected from the group consisting of PA 11 and PA 12.

31. Multilayer structure according to any one of claims 1 to 16, characterized in that said multilayer structure consists of a single reinforcing layer and a sealing layer, wherein said polyamide of layer (a) and / or (b) is: a short-chain aliphatic polyamide; or a long-chain aliphatic polyamide, and said polymer P1j is: a long-chain aliphatic polyamide; or a semi-aromatic polyamide.

32. Multilayer structure according to claim 31, characterized in that said polyamide of layer (a) and / or (b) is a short-chain aliphatic polyamide selected from PA6, PA66 and PA6 / 66.

33. Multilayer structure according to claim 31, characterized in that said polyamide of layer (a) and / or (b) is a long-chain aliphatic polyamide selected from PA1010, PA1012, PA1212, PA11 and PA12.

34. Multilayer structure according to claim 33, characterized in that said polyamide of layer (a) and / or (b) is a long-chain aliphatic polyamide selected from PA11 and PA12.

35. Multilayer structure according to claim 31, characterized in that said polymer P1j of layer (a) and / or (b) is a long-chain aliphatic polyamide selected from PA1010, PA1012, PA1212, PA11 and PA12.

36. Multilayer structure according to claim 35, characterized in that said polymer P1j of layer (a) and / or (b) is a long-chain aliphatic polyamide selected from PA11 and PA12.

37. Multilayer structure according to claim 31, characterized in that said polymer P1j of layer (a) and / or (b) is a semi-aromatic polyamide selected from 11 / 5T or 11 / 6T or 11 / 10T polyamide, MXDT / 10T, MPMDT / 10T and BACT / 10T.

38. Multilayer structure according to any one of claims 1 to 16, 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.

39. Multilayer structure according to claim 38, characterized in that the fibrous material of the composite reinforcing layer is selected from carbon fibers.

40. Multilayer structure according to any one of claims 1 to 16, characterized in that said structure further comprises at least one outer layer consisting of a fibrous material made of continuous glass fibers impregnated with a transparent amorphous polymer, said layer being the outermost layer of said multilayer structure.

41. Method for the production of a multilayer structure as defined in one of claims 1 to 40, characterized in that it comprises the step of producing the sealing layer by extrusion blow molding, rotational molding, injection molding and / or extrusion.

42. Method for the production of a multilayer structure as defined in claim 41, characterized in that it comprises the step of filament winding the reinforcing layer as defined in any one of claims 1 to 14 around the sealing layer as defined in any one of claims 1 to 14 and previously produced.

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