Single-layer or multi-layer structures for transporting, storing, or distributing compressed gases.

Abstract

The present invention relates to a single-layer or multi-layer structure for transporting, storing, or distributing compressed gases, particularly hydrogen, under high pressure, wherein the single-layer or multi-layer structure comprises at least one composite reinforcement layer constituting the outer skin of the structure, which is preferably semi-crystalline, conforming to standard ISO 11357-3: The structure comprises a fibrous material in the form of continuous fibers impregnated with a composition comprising at least one ductile thermoplastic polymer, having a glass transition temperature (Tg) measured according to 2013, wherein the Tg is less than or equal to the operating temperature To, or the Tg is higher than the operating temperature To, with |To-Tg| ≤ +120°C, in particular |To-Tg| ≤ +80°C, in particular |To-Tg| ≤ +50°C, and includes at least one composite reinforcement layer, wherein the impregnated fibrous material constituting the composite reinforcement layer, after integration, has a lateral fracture strain greater than the fracture strain of the fibers at the operating temperature and strain rate representative of use, in particular greater than 1.6%, in particular greater than 1.8%, in particular greater than 2%, and more particularly greater than 2.2%, and the structure does not include an internal seal layer.

Description

[Technical Field]

[0001] The present invention relates to a single-layer or multi-layer structure for transporting, storing, or distributing compressed gases, particularly hydrogen, under high pressure, as well as to the use of the same and a method for producing the same. [Background technology]

[0002] [Conventional technology] Structures for transporting, storing, or distributing compressed gases, particularly hydrogen, under high pressure, preferably using composite reinforcement, i.e., all Type III or IV tanks, are equipped with a liner (seal layer) made of metal (Type III) or polymer (Type IV) to ensure leak prevention of gas, particularly hydrogen, so that the composite layer does not become impermeable to gas, particularly hydrogen, due to the presence of porosity and microcracks in the composite layer.

[0003] Therefore, Type V tanks, i.e., composite tanks without liners, remain an interesting target today because they are more economical (no liners to manufacture) and more efficient (higher volumetric storage efficiency). However, they are currently difficult to realize, particularly due to the early occurrence of lateral microcracks in the composite material when repeatedly pressurized, i.e., microcracks that occur at pressure values ​​equal to a fraction of the operating pressure.

[0004] Therefore, the closest solution to Type V (sometimes called Type 4.5) is to fabricate a monolithic thermoplastic or thermosetting composite tank by welding a composite material to a liner. For this purpose, it may be advantageous to use multiple layers of the composite material, one of which contains a matrix with a melting point close to the melting point of the polymers constituting the liner, thereby limiting the residual thermal stress of the liner.

[0005] International Patent Application Publication No. 2021 / 019 181 describes a multilayer structure selected from tanks, pipes, or tubes for transporting, distributing, or storing hydrogen, comprising at least one sealing layer and at least one composite reinforcement layer, from inside to outside.

[0006] The European Union has just ratified the phasing out of internal combustion engines, which will take effect in 2035.

[0007] One of the goals being pursued is to provide vehicles that produce less pollution. Therefore, electric and hybrid vehicles equipped with batteries aim to gradually replace internal combustion engine vehicles such as gasoline and diesel cars. Now, it has become clear that batteries are among the relatively complex components of a vehicle. Depending on the battery's location inside the vehicle, it may be necessary to protect it from external environments that can be subjected to shocks as well as extreme temperature and humidity changes. Avoiding the risk of fire is also necessary.

[0008] Furthermore, because each battery manufacturer designs batteries for specific models, they are not suitable for widespread use regardless of the selected vehicle model. Therefore, each automaker needs to adapt to the design constraints of the batteries and revise their models accordingly to integrate the batteries.

[0009] Furthermore, it is important to keep the operating temperature below 55°C to prevent damage to the battery cells and maintain the battery's lifespan. Conversely, in some cases, such as during winter, it may be necessary to raise the battery temperature to optimize its operation.

[0010] Furthermore, electric vehicles currently face several challenges, including the need for battery self-sufficiency, the use of rare earth elements (which are not inexhaustible resources) in batteries, and the requirement for each country to produce electricity to charge the batteries.

[0011] Therefore, hydrogen can be converted into electricity by fuel cells and power electric vehicles, thus serving as an alternative to electric batteries. Furthermore, hydrogen is increasingly being considered as a fuel that can potentially be used in conventional combustion engines (known as a "zero-CO2 emission refurbishment technology"), or as a fuel specifically designed to burn hydrogen (in which case emissions, including NOx, are zero).

[0012] However, storing hydrogen is technically difficult and costly, especially for mobile storage, due to its very low molar mass and low liquefaction temperature. To make it effective, however, the storage volume must be small, and the hydrogen must be kept under high pressure, taking into account the vehicle's operating temperature. This is particularly true for fuel cell hybrid road vehicles that require a range of around 600-700 km, but even shorter ranges are required for urban use that complements battery-electric vehicles.

[0013] Therefore, it is necessary to reduce the manufacturing costs of compressed gas tanks, especially hydrogen tanks, while maintaining gas impermeability, particularly with respect to hydrogen, and ensuring sufficient strength so that the tank can be repeatedly used at the operating (or working) pressure, especially during the pressure cycles specific to its use. [Overview of the Initiative]

[0014] Therefore, the present invention relates to a single-layer or multi-layer structure for transporting, storing, or distributing compressed gas, particularly hydrogen, under high pressure, wherein the single-layer or multi-layer structure is The structure comprises at least one composite reinforcement layer constituting the outer shell of the structure, preferably semi-crystalline, and consisting of a fibrous material in the form of continuous fibers impregnated with a composition mainly composed of at least one ductile thermoplastic polymer having a glass transition temperature (Tg) measured according to standard ISO 11357-3:2013, wherein the Tg is less than or equal to the operating temperature To, or the Tg is higher than the operating temperature To, with |To-Tg| ≤ +120°C, in particular |To-Tg| ≤ +80°C, in particular |To-Tg| ≤ +50°C, and includes at least one composite reinforcement layer. The impregnated fiber material constituting the composite material reinforcing layer, after integration, has a transverse rupture strain greater than the rupture strain of the fiber at the operating temperature and strain rate representative of use, particularly greater than 1.6%, particularly greater than 1.8%, particularly greater than 2%, and more particularly greater than 2.2%. The structure does not include an internal seal layer.

[0015] The inventors have unexpectedly found that, in a structure having at least one composite material reinforcing layer, the thermoplastic polymer thereof has ductility and has the Tg as defined above, and the impregnated fiber material constituting the composite material reinforcing layer exhibits the transverse rupture strain as defined above after integration. While omitting the internal seal layer (liner), particularly maintaining its gas impermeability to hydrogen, particularly having sufficient strength to repeatedly use the tank at the operating temperature (or service temperature) in the pressure cycles associated with use. As a result, it has been found that the manufacturing cost of the compressed gas tank, particularly the hydrogen tank, is reduced.

[0016] The structure defined above has several advantages, particularly as follows. - Having a higher volume storage efficiency than a tank equipped with an internal seal layer (liner). - Providing weight reduction and high mass storage efficiency compared to a tank equipped with an internal seal layer (liner). - Eliminating the risk of collapse (delamination) of the liner (seal layer) present in a Type IV tank having an internal seal layer that does not adhere to the composite material reinforcing layer. - Providing an economic benefit regarding the elimination of the manufacturing and drying steps of the liner, and saving the raw materials used in the manufacture of the liner. - Simplifying tank manufacturing by using hot-molded thermoplastic prepregs (or tapes), particularly tapes containing high-performance, high-melting point matrices. - Facilitating the recycling of the final tank by using a single type of material (carbon fiber impregnated with a thermoplastic polymer). - Limiting the number of interfaces and reducing the risk of leakage within the tank. — Eliminating differential stress (between the liner and composite material) during the manufacturing process, thereby reducing internal residual stress. — The tank will have improved fatigue strength (pressure cycles related to filling and emptying cycles), thereby extending the tank's service life.

[0017] Therefore, the composite reinforcement layer consists of at least one layer of solidified fibrous material.

[0018] The term "structure" refers to a hollow, three-dimensional structure capable of withstanding pressure, excluding any other structures.

[0019] The term “structure” refers in particular to a tank, pipe, or tube that includes or consists of one or more layers, especially a tank.

[0020] This structure can be a tank, pipe, or tube for mobile storage of hydrogen, that is, it can be attached to a truck for transporting hydrogen, a vehicle for transporting hydrogen and supplying hydrogen to a fuel cell, such as a train for supplying hydrogen, or a drone for supplying hydrogen, but it can also be a tank, pipe, or tube for fixed storage of hydrogen at a station for distributing hydrogen to vehicles.

[0021] The expression "under high pressure" means several hundred bar, especially 100-900 bar (or 100,000-900,000 hPa), and especially 300-900 bar (or 300,000-900,000 hPa).

[0022] In one embodiment, the structure includes a single layer or consists of a single layer.

[0023] In another embodiment, the structure includes or consists of two layers.

[0024] The term "gas" refers to a substance that is in an expandable and compressible fluid state (gaseous state) under conditions of temperatures above -253°C and pressures below 3000 bar.

[0025] The term "gas" specifically refers to air, helium, oxygen, nitrogen, methane, natural gas, compressed natural gas (CNG) and liquefied natural gas (LNG) (NGVs), liquefied petroleum gas (LPG), propane, butane, hydrogen, and especially methane, natural gas, compressed natural gas (CNG) and liquefied natural gas (LNG) (NGVs), liquefied petroleum gas (LPG), propane, butane, hydrogen, and especially hydrogen.

[0026] "Operating temperature (To)" refers to the temperature at which the structure is used. Needless to say, this temperature varies depending on the type of gas being transported (or carried), stored, or delivered, and how it is used. Therefore, during rapid filling, the structure (i.e., tank or pipe) is heated, and To increases as the pressure rises. During rapid discharge, the structure is cooled, and To decreases as the pressure drops.

[0027] Applications include storing gas, particularly hydrogen, at gas refueling stations, and especially hydrogen for all types of vehicles, light vehicles and heavy vehicles, for the mobility, industrial, storage, and energy markets.

[0028] Another potential application is the transportation of hydrogen from offshore wind turbines to land, where seawater is electrolyzed to produce green hydrogen, which is then transported to onshore storage or refueling stations.

[0029] In one embodiment, the operating temperature To is in the range of -80°C to +160°C.

[0030] During use, the structure must be able to withstand the strain on the structure in accordance with the temperature and pressure of the compressed gas. Composite reinforcement allows the structure to withstand the internal pressure generated within the structure by the fluid being transported (or carried), stored, or distributed.

[0031] According to a course by Professor Antoine Chateauminois of ESCPI (Composites Course, Failure Processes of Unidirectional (UD) Composites, Sheet 3, May 2000), under transverse loading, failure of the unidirectional layer is accompanied by matrix cracking and delamination at the fiber / matrix interface. This failure mode generally corresponds to the initial damage observed in cross-laminated composites under tensile load. Then, transverse cracks, called intralaminar cracks, are observed in layers misaligned with respect to the load axis. These failures occur considerably earlier than failure of layers oriented at 0° to the load axis.

[0032] To prevent the occurrence of these lateral cracks, the impregnated fibrous material constituting the composite reinforcement layer constituting the outer shell of the structure must, after integration, exhibit a lateral fracture strain greater than the fracture strain of the fibers at the operating temperature and strain rate representative of use, particularly greater than 1.6%, particularly greater than 1.8%, particularly greater than 2%, and more specifically greater than 2.2%.

[0033] In one embodiment, the operating temperature To is in the range of -80°C to +150°C.

[0034] The behavior of materials, such as their brittleness and ductility, depends particularly on the strain rate.

[0035] In one embodiment, the strain rate representative of use is 10 -5 ~10 2 s -1 , especially 10 -5 s -1 ~1s -1 , especially 10 -3 ~1s -1 That is the case.

[0036] The term "ductile" refers to the ability of a material to plastically deform without breaking.

[0037] Therefore, when the transverse fracture strain of the composite material occurs after the fibers break, it has been found that there is no problem of early microcracks occurring during the use of the tank, and the use of the liner can be omitted. Considering that the semi-crystalline thermoplastic matrix composite material is well integrated and has no defects (such as porosity, microcracks related to the thermal manufacturing cycle, etc.) before receiving mechanical stress, and it is known that its hydrogen permeability is extremely low, this can be achieved more easily.

[0038] Therefore, this structure is composed of a composite material with sufficient transverse mechanical properties to prevent microcracks. This resistance is provided by a composite material with good transverse resistance even during the pressure cycles inherent in use, so it is sufficient for repeated use of the tank at the operating pressure.

[0039] The transverse fracture strain of the obtained composite reinforcement layer is evaluated on a coupon according to the standard ISO 527-5:2021: A plate with a thickness of 2 mm and a size of 300×300 mm is composed of a stack of 16 layers of unidirectional UD layers of impregnated fiber material, and is obtained by planar laser deposition followed by autoclave consolidation. From the obtained plate, transverse tensile test specimens are machined (T90°) so that the fiber axis is perpendicular to the axis of the test specimen, and the strain rate is 10 -5 s -1 、10 -3 s -1 、1s -1 及び10 2 s -1 、and tested at temperatures of -60°C, +23°C, and +85°C.

[0040] The plates tested were manufactured using a method different from the manufacturing method of the structure of the present invention, but the results of the transverse fracture strain obtained for this plate guarantee the good behavior of the structure, especially the leak prevention property of the structure under pressure.

[0041] Transverse fracture strain can also be evaluated by other methods, such as the following: - In a unidirectional composite material composed of the same type of fiber and the same polymer matrix, by applying tension perpendicular to the fiber axis to the composite material, a fracture strain value greater than the fracture strain value of the fiber used, preferably greater than 1.6%, particularly greater than 1.8%, particularly greater than 2%, and more specifically greater than 2.2%, can be obtained, especially at the operating temperature and strain rate representative of use. - Alternatively, on a laminate having orientations of 0 to 90°, tension is applied in one of two directions, and in particular, fibers stressed in the longitudinal direction (i.e., the direction of strain imposed by the tensile testing machine) must break before the fibers in the transverse layers break in the direction of tension. Alternatively, for laminates having an orientation of 0 to 90°, in a biaxial bending process, a plate is pre-placed on a hollow support and punched out in the lateral direction at the center of the plate's thickness, particularly in the direction outside the fiber axis, a radial or orthogonal radial strain value greater than the fracture strain of the fibers used is obtained, preferably greater than 1.6%, particularly greater than 1.8%, particularly greater than 2%, and more specifically greater than 2.2%. Alternatively, for laminates having an orientation of 0 to 90°, by applying tension simultaneously in two directions of the fibers of the laminate, particularly in the out-of-axis direction of the fibers, under biaxial tension, a radial or orthogonal radial strain value greater than the breaking strain of the fibers used, preferably greater than 1.6%, particularly greater than 1.8%, particularly greater than 2%, and more specifically greater than 2.2%, can be obtained at the operating temperature and strain rate representative of use. Alternatively, for laminates having a quasi-iso orientation of 0° / ±45° / 90°, a fracture strain greater than the fracture strain of the fibers used, preferably greater than 1.6%, particularly greater than 1.8%, particularly greater than 2%, and more specifically greater than 2.2%, can be obtained at the operating temperature and strain rate representative of use by applying a tensile force to one of the four directions of the laminate fibers. - Alternatively, for laminates having quasi-equal orientation of 0° / +-45° / 90°, and which are formed by pre-placing a plate on a hollow support in a biaxial bending process, and punching out the plate laterally in the center with respect to its thickness, particularly in the direction outside the fiber axis, it is required that the radial or orthogonal radial strain value be 1.6%, particularly 1.8%, particularly 2%, or more specifically 2.2%, at the operating temperature and strain rate representative of use. Alternatively, in biaxial tension, for laminates having quasi-isogonal orientations of 0° / ±45° / 90°, applying tension in two of the four directions of the plate fibers allows for the determination of radial or orthogonal radial strain values ​​of 1.6%, 1.8%, 2%, and more specifically 2.2%, at typical operating temperatures and strain rates.

[0042] Tensile tests are performed on Type 1BA dumbbells at various temperatures in accordance with the standard ISO 527-1:2012.

[0043] The pore content of the consolidated plate is less than 5%, and especially less than 2%.

[0044] Pore ​​content can be determined by image analysis.

[0045] It can also be determined by calculating the relative difference between theoretical and experimental densities (a common method). a) The required data is as follows: - Density of thermoplastic matrix - Fiber density - Standard weight of reinforcing material: • Line mass (g / m), e.g., 1 / 4-inch tape (obtained from a single roving) • Mass per unit area (g / m²) 2 ), for example, in the case of wide tapes or fabrics b) Measurements to be performed: For the results to be representative of the material being studied, the number of samples must be at least 30.

[0046] The measurements to be performed are as follows: - Size of collected samples: ○ Length (if the line mass is known) ○ Length and width (when the mass per unit area is known) - Experimental density of collected samples: 〇 Mass measurement in air and water - The fiber content is measured in accordance with ISO 1172:1999, or by thermogravimetric analysis (TGA) as described, for example, in document B. Benzler, Applicationslabor, Mettler Toledo, Giesen, UserCom 1 / 2001.

[0047] The carbon fiber content can be determined according to ISO 14127:2008.

[0048] Determining the theoretical mass content of fibers: a) Determination of the theoretical mass content of the fibers: [Mathematics 1] TIFF2026518129000001.tif10170 formula, m l Tape linear mass, L is the length of the sample, and Ms air This is the mass of the sample measured in air.

[0049] Changes in fiber mass content are assumed to be directly related to changes in matrix content, without considering fluctuations in the amount of fiber in the reinforcing material.

[0050] b) Determination of theoretical density: [Math 2] In formula TIFF2026518129000002.tif16170, dm and df are the densities of the matrix and fibers, respectively.

[0051] The theoretical density calculated in this way is the density that can be used when the sample is not porous.

[0052] c) Evaluation of porosity: Porosity is the relative difference between theoretical density and experimental density.

[0053] In one embodiment, the plastic threshold of a ductile thermoplastic polymer impregnated into a fibrous material in the form of continuous fibers is less than 120 MPa, particularly less than 85 MPa, particularly less than 60 MPa, and particularly less than 50 MPa.

[0054] The plasticity threshold, denoted by σ0, represents the boundary between the elastic and plastic regions.

[0055] When a part is subjected to stress (such as being pulled, compressed, or twisted), it initially undergoes reversible strain (elastic strain), meaning its dimensions change, but it returns to its original shape once the stress is removed. Certain materials, known as brittle, will break in this strain mode if the stress is too high.

[0056] In materials described as ductile, permanent strain occurs when the stress (i.e., the stress within the material) increases sufficiently, and when the stress stops, the part remains deformed (i.e., the stress within the material reaches the material's plasticity threshold, initiating an irreversible strain process).

[0057] The plastic threshold can be determined by tensile testing of ISO 527-1BA specimens.

[0058] A tensile test involves pulling a rod, and as shown in Figure 1, a one-dimensional stress-strain curve of the material can be extracted. During monotonic load increase, the curve can be seen to have two phases. The first phase. This is defined by σ < σ0. The relationship between σ and ε is linear. If the load does not exceed the stress limit σ0, the removal of the load follows the same path. It is reversible, and this is the definition of elasticity. The behavioral relationship is described as follows: σ = E.ε In the equation, E is Young's modulus and is identified as the slope of the line.

[0059] The second phase, characterized by σ > σ0, is when the material enters the plastic region. To observe the irreversibility associated with plastic behavior, the load must be removed from the specimen. Load removal is performed starting from a strain greater than the elastic strain εe = σ / E. At this strain stage, the stress value σ of the material becomes equal to the initial elastic limit σ0 and remains constant for strains greater than εe; in other words, the material exhibits complete plastic behavior. This is generally not true for polymers, where, once the strain ε exceeds the elastic strain εe, the stress of the material continues to increase beyond σ0 with increasing total strain εt, but the slope is much gentler than the slope imposed by the modulus in the elastic strain region. This is called work hardening, and the slope of the curve connecting stress and strain is the tangential modulus Et, whose value is much lower than the value of the modulus E. Conversely, when the load is removed from the material, that is, when the applied strain decreases, the decrease in stress follows a straight line with slope E. Therefore, when the stress becomes zero, it is observed that the strain is not zero; in other words, residual strain, which is plastic strain, is observed. In this way, an additive division is identified that divides uniaxial strain into an elastic part and a plastic part. ε = ε e + ε p In the formula, ε e This is elastic strain, which is reversible (recoverable when the load is removed), and is governed by the law of elasticity (σ=Eε). e ) is related to stress through ε p This is plastic strain, and it is irreversible or residual.

[0060] In a simple (uniaxial) tensile test, irreversible elongation of the specimen occurs due to plastic strain. In the stress-strain curve, the elastic portion corresponds to the straight portion of the curve, and the plastic region corresponds to the inflection point of this curve. The stress limit between the two regions defines the elastic limit, which is denoted here as σo (in metals, this is often called Re 0.2%, the nominal stress at 0.2% plastic strain, and is a value very close to the plastic threshold σo, but is actually easier to measure).

[0061] This mechanical analysis is well applicable to metals with T < Tf / 2, but remains an approximation in the case of polymers, which are significantly affected by the temperature and strain rate that reflect the occurrence of viscous phenomena in polymer strain. Therefore, the elastic modulus and stress at the plastic threshold depend on the strain rate and temperature, just like the plastic strain, and this is called viscoplastic strain. The strain division is expressed as follows. ε = ε e + ε vp And ε vp can be determined in exactly the same way as the above description of plastic strain, but this value needs to be determined immediately when the stress becomes zero. After a rest without stress for a certain period, the polymer may recover a part of this strain, and the viscoplastic strain depends on the observation time.

[0062] Furthermore, the occurrence of these viscous strain phenomena means that the transition from elastic behavior to plastic behavior is gradual and the stress-strain curve has a curvature in the plastic threshold region, which actually makes it difficult to measure σo. Therefore, it is common to determine σo by the intersection of the elastic modulus and the tangent modulus. As described above, due to the influence of the strain rate and temperature, this value depends on the stress condition of the polymer, and this is exactly what determines whether transverse cracks occur in the composite material with this polymer as the matrix. If the value of σo becomes too high due to temperature decrease or strain rate increase, failure occurs preferentially at the interface between the fiber and the matrix rather than in the resin, and the resin cannot undergo (visco)plastic deformation. Conversely, when the temperature is sufficiently high or the strain rate is sufficiently low, the value of the plastic threshold σo is low enough for the polymer to undergo (visco)plastic deformation, and the failure in the resin occurs at a high strain level, usually exceeding 1.6%, especially exceeding 1.8%, particularly exceeding 2%, and even more particularly exceeding 2.2%, which is larger than the fiber fracture strain.

[0063] The fracture strain of the fiber is evaluated by a tensile test (in accordance with ISO 527-1: 2012) on dry fibers (or bundles of dry fibers), which enables the measurement of the fracture stress, elastic modulus, and fracture strain of the fiber.

[0064] These three quantities are related by the equation S = E × epsilon (S = fracture stress, E = elastic modulus, epsilon = fracture strain).

[0065] In one embodiment, the structure does not include an external leaktightness layer. "External leaktightness layer" means a leaktightness layer located on top of the composite reinforcement layer.

[0066] Regarding the excluded internal leak-proof layer An excluded internal leak-proof layer is a leak-proof layer made of a fiber-free polymer or polymer composition, regardless of the polymer or polymer composition from which it is made.

[0067] Regarding composite reinforcement layers and thermoplastic polymers One or more composite reinforcement layers may be present.

[0068] Each of the aforementioned layers consists of a composition mainly comprising at least one thermoplastic polymer. The number of layers present is particularly 1 to 10, particularly 1 to 5, notably 1 to 3, and preferably 1.

[0069] The term "predominantly" 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.

[0070] Advantageously, the at least one major polymer is present in an amount exceeding 60% by weight, particularly exceeding 70% by weight, particularly exceeding 80% by weight, and especially exceeding 90% by weight, based on the total weight of the composition.

[0071] The composition impregnated into the fibrous material of the reinforcing layer may also include an impact resistance modifier and / or additives.

[0072] Additives can be selected from antioxidants, heat stabilizers, UV absorbers, light stabilizers, lubricants, inorganic fillers, flame retardants, nucleating agents, plasticizers, and dyes.

[0073] Advantageously, the composition mainly consists of the thermoplastic polymer, 0-5% by weight of an impact modifier, and 0-5% by weight of an additive, with the total compositional content equal to 100% (based on a minimum of 90% thermoplastic polymer).

[0074] At least one major polymer in each layer may be the same or different.

[0075] In one embodiment, at least one main polymer is present within the composite reinforcement layer.

[0076] In one embodiment, each reinforcing layer contains the same type of polymer.

[0077] Thermoplastic polymers The terms "thermoplastic" or "thermoplastic polymer" refer to materials that are generally solid at room temperature, and can be semi-crystalline or amorphous, particularly semi-crystalline materials that soften as the temperature rises, especially after exceeding the glass transition temperature (Tg), flow at higher temperatures if amorphous, or rapidly melt above the "melting point" (Tm) if semi-crystalline, and become solid again during a temperature decrease below the crystallization temperature Tc (for semi-crystalline materials) and below the glass transition temperature (for amorphous materials).

[0078] Tg, Tc, and Tm are determined by differential scanning calorimetry (DSC) in accordance with standards 11357-2:2013 and 11357-3:2013, respectively.

[0079] The thermoplastic polymer in the composition is ductile. This is due to its elastic strain ε e When deformation exceeds a certain point, it means that (visco)plastic strain is observed.

[0080] The thermoplastic polymer of at least one composition of the composite reinforcement layer has a Tg that is less than or equal to the operating temperature To, or a Tg that is higher than the operating temperature To, such that |To-Tg| ≤ +120°C, in particular |To-Tg| ≤ +80°C, and in particular |To-Tg| ≤ +50°C.

[0081] In the first deformation, the thermoplastic polymer has a Tg below the operating temperature To, regardless of the position of the reinforcing layer.

[0082] In one embodiment of this first modification, the reinforcing layer, which is made of a composition containing a thermoplastic polymer having a Tg of less than or equal to an operating temperature To, is the innermost layer that comes into contact with the compressed gas.

[0083] In another embodiment of this first modification, the reinforcing layer is the outermost reinforcing layer of the structure, and the reinforcing layer is made of a composition comprising a thermoplastic polymer having a Tg below an operating temperature To.

[0084] In the second variation, the Tg of the thermoplastic polymer is higher than the operating temperature To, with |To-Tg| ≤ +120°C, in particular |To-Tg| ≤ +80°C, and in particular |To-Tg| ≤ +50°C.

[0085] In one embodiment of this second modification, the reinforcing layer, which is made of a composition containing a thermoplastic polymer with a Tg of |To-Tg| ≤ +120°C, is the innermost layer that comes into contact with the compressed gas.

[0086] In another embodiment of this second modification, the reinforcing layer is the outermost reinforcing layer of the structure, and the reinforcing layer is made of a composition comprising a thermoplastic polymer having a Tg of |To-Tg| ≤ +120°C.

[0087] In the third variation, the thermoplastic polymer has a Tg higher than its operating temperature To, where |To-Tg| ≤ +80°C.

[0088] In one embodiment of this third modification, the reinforcing layer, which is made of a composition containing a thermoplastic polymer having a Tg such that |To-Tg|≦+80℃, is the innermost layer that comes into contact with the compressed gas.

[0089] In another embodiment of this third modification, the reinforcing layer is the outermost reinforcing layer of the structure, and is made of a composition comprising a thermoplastic polymer having a Tg such that |To-Tg| ≤ +80°C.

[0090] In the fourth variation, the thermoplastic polymer has a Tg higher than its operating temperature To, where |To-Tg| ≤ +50°C.

[0091] In one embodiment of this fourth modification, the reinforcing layer, which is made of a composition containing a thermoplastic polymer with a Tg of |To-Tg| ≤ +50°C, is the innermost layer that comes into contact with the compressed gas.

[0092] In another embodiment of this fourth modification, the reinforcing layer is the outermost reinforcing layer of the structure, and is made of a composition comprising a thermoplastic polymer having a Tg such that |To-Tg| ≤ +50°C.

[0093] In one embodiment of these four variations, all reinforcing layers comprising a thermoplastic polymer composition are identical and therefore correspond to both the innermost and outermost reinforcing layers of the structure.

[0094] The number-average molecular weight Mn of the thermoplastic polymer is preferably in the range of 10,000 to 40,000 g / mol, and preferably in the range of 12,000 to 30,000 g / mol.

[0095] The Mn value is specifically determined by calculation, starting from the content of terminal functional groups determined by potentiometric titration in the solution.

[0096] The Mn mass can also be determined by size exclusion chromatography or NMR.

[0097] Examples of semi-crystalline thermoplastic polymers suitable for use in the present invention include the following: polyamide, Polyamide polyether, polyester, Polyaryl ether ketone (PAEK), Polyetheretherketone (PEEK), Polyetherketone (PEKK), Polyetherketone etherketone ketone (PEKEKK), Polyimides, especially polyetherimides (PEI) or polyamideimides, Polysulfones (PSU), especially polyarylsulfones such as polyphenylsulfone (PPSU), Polyethersulfone (PES).

[0098] Semicrystalline polymers are particularly preferred.

[0099] In one embodiment, the thermoplastic polymer is a polyamide, particularly a semicrystalline polyamide.

[0100] polyamide The nomenclature used to define polyamides is described in the standard ISO 1874-1:2011 Plastics - Polyamide (PA) molding and extrusion materials - Part 1: Designation, particularly on page 3 (Tables 1 and 2), and is well known to those skilled in the art.

[0101] The polyamide may be a homopolyamide, a copolyamide, or a mixture thereof.

[0102] Advantageously, the polyamide, particularly the semicrystalline polyamide, has a C / N ratio of 5 or more, preferably 8 or more, particularly 9 or more, and more particularly 10 or more.

[0103] The C / N ratio refers to the ratio of the number of carbon atoms to the number of nitrogen atoms in a polyamide.

[0104] In the case of PA-XY type homopolyamides, the number of carbon atoms per nitrogen atom is the average of units X and Y.

[0105] In the case of copolyamides, the number of carbon atoms per nitrogen atom is calculated according to the same principle. The calculation is performed on a molar-proportional (pro rata) basis for different amide units.

[0106] Polyamides, particularly semicrystalline polyamides, may be aliphatic, alicyclic, or semi-aromatic.

[0107] In the first variation, semicrystalline polyamides in particular are aliphatic polyamides.

[0108] The aforementioned at least one aliphatic polyamide (particularly semicrystalline) can be obtained from the polycondensation of at least one lactam, or from the polycondensation of at least one amino acid, or from the polycondensation of at least one diamine X and at least one dicarboxylic acid Y.

[0109] If the at least one aliphatic polyamide, particularly a semicrystalline polyamide, is obtained from the polycondensation of at least one lactam, it may comprise a single lactam or multiple lactams.

[0110] When the at least one aliphatic polyamide (particularly semicrystalline) is obtained from the polycondensation of at least one lactam, the at least one lactam is selected from C6-C18 lactams, preferably C8-C12 lactams, and more preferably C10-C12 lactams.

[0111] Advantageously, the at least one aliphatic polyamide, which is particularly semicrystalline, is obtained from the polycondensation of a single lactam, the lactam can be selected particularly from caprolactam, lauryllactam and undecanolactam, and advantageously from lauryllactam.

[0112] When the at least one aliphatic polyamide, particularly a semicrystalline polyamide, is obtained from the polycondensation of at least one amino acid, the at least one amino acid can be selected from C6-C18 amino acids, preferably C10-C18 amino acids, and more preferably C10-C12 amino acids.

[0113] C6-C12 amino acids include, in particular, 6-aminohexanoic acid, 9-aminononanoic acid, 10-aminodecanoic acid, 10-aminoundecanoic acid, 12-aminododecanoic acid, and 11-aminoundecanoic acid, as well as their derivatives, especially N-heptyl-11-aminoundecanoic acid.

[0114] If the aforementioned at least one aliphatic polyamide, particularly a semicrystalline polyamide, is obtained from the polycondensation of at least one amino acid, it may comprise a single amino acid or multiple amino acids.

[0115] Advantageously, the semi-crystalline aliphatic polyamide is obtained from the polycondensation of a single amino acid, the amino acid being selected from 11-aminoundecanoic acid and 12-aminododecanoic acid, preferably 11-aminoundecanoic acid.

[0116] In particular, when the semi-crystalline aliphatic polyamide is obtained from the polycondensation of at least one diamine X and at least one diacid Y, the diamine is C4-C36, preferably C6-C18, preferably C6-C12, more preferably C10-C12, the at least one diacid Y is C4-C36, preferably C6-C18, preferably C6-C12, more preferably C8-C12, the at least one diamine X is an aliphatic diamine, and the at least one diacid Y is an aliphatic diacid.

[0117] The diamine may be linear or branched. Preferably, it is linear.

[0118] The at least one C4-C36 diamine X may be selected from, in particular, 1,4-butanediamine, 1,5-pentamethylenediamine, 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonameethylenediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine, 1,13-tridecamethylenediamine, 1,14-tetradecamethylenediamine, 1,16-hexadecamethylenediamine, and 1,18-octadecamethylenediamine, octadecenediamine, eicosanediamine, docosanediamine, and diamines obtained from fatty acids.

[0119] Advantageously, the at least one diamine X is C4-C18 and is selected from 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonameethylenediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine, 1,13-tridecamethylenediamine, 1,14-tetradecamethylenediamine, 1,16-hexadecamethylenediamine, and 1,18-octadecamethylenediamine.

[0120] Advantageously, the at least one C6-C12 diamine X is selected in particular from 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonameethylenediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine, and 1,12-dodecamethylenediamine.

[0121] Advantageously, the diamine X used is a C10-C12 diamine, particularly selected from 1,10-decamethylenediamine, 1,11-undecamethylenediamine, and 1,12-dodecamethylenediamine.

[0122] The at least one dicarboxylic acid Y is C4 to C36 and can be selected from succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, undecanediic acid, dodecanediic acid, brassic acid, tetradecanediic acid, pentadecanediic acid, hexadecanedioic acid, octadecanediic acid, and diacides obtained from fatty acids.

[0123] The diacitor may be linear or branched. Advantageously, it is linear.

[0124] Advantageously, the at least one dicarboxylic acid Y is C6-C18 and is selected from adipic acid, suberic acid, azelaic acid, sebacic acid, undecanediic acid, dodecanediic acid, brassic acid, tetradecanediic acid, pentadecanediic acid, hexadecanedioic acid, and octadecanediic acid.

[0125] Advantageously, the at least one dicarboxylic acid Y is C6-C12 and is selected from adipic acid, suberic acid, azelaic acid, sebacic acid, undecanediic acid, and dodecanediic acid.

[0126] Advantageously, the at least one dicarboxylic acid Y is C8-C12 and is selected from suberic acid, azelaic acid, sebacic acid, undecanediic acid, and dodecanediic acid.

[0127] In one embodiment, the semi-crystalline polyamide impregnated into the continuous fibers of the composite reinforcement layer is a semi-crystalline aliphatic polyamide, particularly PA410, PA56, PA59, PA510, PA512, PA513, PA514, PA6, PA66, PA69, PA610, PA612, PA614, PA618, PA1010, PA1012, PApip10, PApip12, PA1014, PA1018, PA1210, PA1212, PA1214, PA1218, PA11, PA12, preferably PA6, PA66, PA410, PA510, PA69, PA610, PA512, PA612, PA Selected from 514, PA614, PA618, PA1010, PA1012, PA1014, PA1018, PA1214, PA1218, PA11 and PA12, more preferably PA11 or PA12, and mixtures thereof.

[0128] Advantageously, semi-crystalline aliphatic polyamides, in particular, are partially or entirely bio-based.

[0129] In the second variation, semicrystalline polyamides are specifically semi-aromatic polyamides.

[0130] Here, the term "semi-aromatic polyamide" means a polyamide derived from monomers comprising at least one monomer having an aromatic group and at least one aliphatic or alicyclic monomer.

[0131] Examples of suitable monomers containing aromatic groups include terephthalic acid (T) and its derivatives, isophthalic acid (I) and its derivatives, naphthalenedicarboxylic acid (N) and its derivatives, C6-C20 aromatic diamines, and arylamines such as p-xylylenediamine (PXD) and m-xylylenediamine (MXD).

[0132] Advantageously, suitable monomers containing aromatic groups are terephthalic acid (T), isophthalic acid (I), p-xylylenediamine (PXD), m-xylylenediamine (MXD), and BAC.

[0133] The semi-aromatic polyamide may be of the XY type, where X is an alkyl aromatic diamine (or arylamine) and Y is a dicarboxylic acid selected from linear or branched aliphatic dicarboxylic acids, or X is a linear or branched aliphatic diamine and Y is selected from aromatic dicarboxylic acids.

[0134] Semi-aromatic polyamides that may be optionally modified with urea units are, in particular, semi-aromatic polyamides of formula X / YAr as described in European Patent No. 1 505 099, and especially semi-aromatic polyamides of formula A / XT, where A is selected from units obtained from amino acids, units obtained from lactams, and units corresponding to the formula (Ca-diamine)(Cb-diacid), where a represents the number of carbon atoms of the diamine, b represents the number of carbon atoms of the diacid, and a and b are between 4 and 36, preferably between 9 and 18, where the (Ca-diamine) unit is selected from linear or branched aliphatic diamines, alicyclic diamines, and alkyl aromatic diamines, and the (Cb-diacid) unit is selected from linear or branched aliphatic diacids, alicyclic diacids, and aromatic diacids; 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 6 and 36, preferably between 9 and 18, and is particularly a polyamide of formula A / 6T, A / 9T, A / 10T or A / 11T, where A is as defined above, and is particularly a polyamide PA 6 / 6T, PA 66 / 6T, PA 6I / 6T, PA MPMDT / 6T, PA MXDT / 6T, PA PA 11 / 10T, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA 11 / BACT / 10T, PA 11 / BACT / 6T, PA 11 / MPMDT / 10T, PA 11 / MXDT / 10T, and block copolymers, particularly polyamide / polyether (PEBA) copolymers.

[0135] T corresponds to terephthalic acid, MXD to m-xylenediamine, MPMD to methylpentamethylenediamine, and BAC to bis(aminomethyl)cyclohexane.

[0136] The semi-crystalline polyamides impregnated into the continuous fibers of the composite reinforcement layer are semi-aromatic polyamides, particularly PA MPMDT / 6T, PA 11 / 10T, PA 11 / BACT, PA 5T / 10T, PA 11 / 6T / 10T, PA MXDT / 4T, PA MXDT / 6T, PA MXDT / 10T, PA MPMDT / 4T, PA MPMDT / 6T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 4T, PA BACT / 10T / 6T, PA 11 / BACT / 4T, PA 11 / BACT / 6T, PA 11 / BACT / 10T, PA 11 / MXDT / 4T, PA 11 / MXDT / 6T, PA 11 / MXDT / 10T, PA 11 / MPMDT / 4T, PA Selected from 11 / MPMDT / 6T, PA 11 / MPMDT / 10T, PA 11 / MXDT / 10T, PA11 / 5T / 10T, and mixtures thereof.

[0137] Advantageously, semi-crystalline semi-aromatic polyamides, in particular, are partially or entirely bio-based.

[0138] Regarding fiber materials before and after impregnation Throughout this explanation, the terms ribbon or strip of fibrous material impregnated with a thermoplastic polymer or tape are used and may refer to the same thing.

[0139] The fibers constituting the aforementioned fibrous material are, in particular, mineral, organic, or plant-derived fibers in the form of tufts.

[0140] In one embodiment, for carbon fibers, the number of fibers per tuft is 24K or more (i.e., 24,000 fibers per tuft), and especially 24-30K.

[0141] In another embodiment, the number of carbon fibers per bundle is greater than 30K, and particularly greater than 50K.

[0142] Advantageously, the base weight of the glass fiber should be 1200 Tex or more, especially 4800 Tex or less, and especially 1200-2400 Tex.

[0143] Examples of mineral-derived fibers include carbon fibers, glass fibers, basalt or basalt-based fibers, silica fibers, or silicon carbide fibers. Examples of organic fibers include fibers based on thermoplastic polymers or thermosetting polymers, such as semi-aromatic polyamide fibers, aramid fibers, and polyolefin fibers. Preferably, these are based on amorphous thermoplastic polymers, and when the thermoplastic polymer or polymer blend constituting the impregnation matrix is ​​amorphous, they have a glass transition temperature Tg higher than that of the thermoplastic polymer or polymer blend constituting the impregnation matrix, or when the polymer or blend is semi-crystalline, they have a glass transition temperature Tg higher than that of the thermoplastic polymer or polymer blend constituting the impregnation matrix. Advantageously, these are based on semi-crystalline thermoplastic polymers, and when the impregnation matrix is ​​amorphous, they have a melting point Tm higher than that of the thermoplastic polymer or polymer blend constituting the impregnation matrix, and when the impregnation matrix is ​​semi-crystalline, they have a melting point Tm higher than that of the thermoplastic polymer or polymer blend constituting the impregnation matrix. Therefore, there is no risk of the organic fibers constituting the fibrous material dissolving when impregnating the thermoplastic matrix of the final composite material. Examples of plant-derived fibers include natural fibers made from flax, hemp, lignin, bamboo, silk (especially spider silk and sisal), and other cellulosic fibers (especially viscose). These plant-derived fibers may be used in their pure form, or treated or coated with a coating layer to facilitate adhesion and impregnation of the thermoplastic polymer matrix.

[0144] The fiber may also have supporting threads.

[0145] These constituent fibers can be used individually or as a mixture. Therefore, organic fibers can be mixed with mineral fibers and impregnated with a thermoplastic polymer to form an impregnated fiber material.

[0146] Organic fiber tufts may have several basic weights. They may also have multiple dimensions and shapes.

[0147] Fibers are in the form of continuous fibers and constitute 2D fabrics, nonwoven fabrics (NCF), unidirectional (UD) fibers, or braids or tufts of nonwoven fibers. The fibers that make up a fibrous material can also take the form of a mixture of these reinforcing fibers of different dimensions and shapes.

[0148] Preferably, the fibrous material is selected from glass fibers, carbon fibers, basalt fibers, and basalt-based fibers.

[0149] It is advantageous to use it in the form of one or more tufts.

[0150] To improve the physicochemical bonding between polymers and fibers, fiber manufacturers use sizing agents with varying compositions and contents. However, because these are generally organic (thermosetting or thermoplastic resin types) and are often formulated for impregnating fibers with low-melting-point polymers or low-Tg thermosetting polymers, sizing agents often degrade during the impregnation process, particularly during the pre-impregnation steps (melting, passing through solvent solution, etc.) and / or during the melting step of the thermoplastic matrix, especially when the thermoplastic matrix has a high melting point (for semi-crystalline polymers) or a high Tg (for amorphous or thermosetting polymers). Furthermore, because the chemical compatibility between the matrix polymer and the sizing agent is not always optimal, the resulting bond strength can vary positively or negatively compared to that observed in unsized fibers.

[0151] However, in some cases, sizing adjustments are essential or even unavoidable. Unsized fibers are difficult to handle. More specifically, sizing not only promotes adhesion between the matrix and the fibers, but also protects fibers such as carbon fibers and glass fibers, acting as a binder and allowing them to be handled without damage.

[0152] In impregnated materials, also known as "ready-to-use" materials, a mixture of polymers or thermoplastic impregnating polymers is evenly and uniformly distributed around the fibers. In this type of material, the thermoplastic impregnating polymer or polymer blend is distributed as uniformly as possible within the fibers to achieve minimal porosity, i.e., minimal voids between fibers. Specifically, the porosity present in this type of material can act as stress concentration points when subjected to mechanical tensile stress, for example, creating initiation points for rupture in the impregnated fiber material and potentially making it mechanically brittle. Therefore, the uniform distribution of polymers or polymer blends improves the mechanical strength and uniformity of composites formed from these impregnated fiber materials.

[0153] In the first embodiment, the fiber content in the impregnated fiber material is 30% to 65% by volume, particularly 45% to 65% by volume, preferably 50% to 60% by volume, especially 52% to 60% by volume, and particularly 53% to 57% by volume.

[0154] The fiber content is determined according to ISO 1172:1999 or by thermogravimetric analysis (TGA) as described, for example, in document B. Benzler, Applicationslabor, Mettler Toledo, Giesen, UserCom 1 / 2001.

[0155] The carbon fiber content can be determined according to ISO 14127:2008.

[0156] In the second embodiment, the fiber content in the impregnated fiber material is 30% to 50% by volume, particularly 30% to 40% by volume.

[0157] The impregnation content can be measured by dividing the surface area of ​​the polymer-impregnated tape by the total surface area of ​​the product (sum of the impregnated surface area and the pore surface area) using image analysis of the tape's cross-section (especially using a microscope, camera, or digital camera). To obtain high-quality images, it is desirable to coat a transversely cut piece of tape with a standard polishing resin and polish it using a standard protocol that allows the sample to be observed under a microscope at least 6x magnification.

[0158] Advantageously, the pore content of the impregnated fiber material is less than 5%, and particularly less than 2%.

[0159] It should be noted that it is difficult to reduce the pore content to zero, and therefore, it is advantageous for the pore content to be greater than 0% but less than the aforementioned content.

[0160] The pore content corresponds to the content of closed pores and can be determined by electron microscopy or, as described above, as the relative difference between the theoretical density and experimental density of the impregnated fiber material.

[0161] In all cases, the pore content is the average content of a considerable volume of the fibrous material, i.e., a volume greater than or equal to a 500m reel of tape with an average width of 12.7 mm (1 / 2 inch) and a thickness of 140 μm.

[0162] Regarding single-layer or multi-layer structures The structure can be single-layered or multi-layered.

[0163] Single-layer structure According to one embodiment, the structure is single-layer and includes at least one composite reinforcement layer as defined above.

[0164] In the first variation, the structure is single-layer and consists of a single composite reinforced layer as defined above, excluding other composite or non-composite layers.

[0165] The reinforcing layer may consist of one or more layers.

[0166] In one embodiment of this first modification, the single-layer structure is characterized in that the fiber volume content of the composite reinforcement layer is between 50% and 60%, particularly between 53% and 57%.

[0167] Advantageously, in this embodiment of the first modification, the operating temperature is above room temperature.

[0168] In another embodiment of this first modification, the single-layer structure is characterized in that the fiber volume content of the composite reinforcement layer is between 30% and 50%, particularly between 30% and 40%.

[0169] Advantageously, in this embodiment of the first modification, the operating temperature is below -252.8°C at atmospheric pressure.

[0170] Advantageously, in these modifications and embodiments, the thermoplastic polymer of the composition impregnated into the fiber material is particularly a semicrystalline aliphatic polyamide, especially PA410, PA56, PA59, PA510, PA512, PA513, PA514, PA6, PA66, PA69, PA610, PA612, PA614, PA618, PA1010, PA1012, PApip10, PApip12, PA1014, PA1018, PA1210, PA1212, PA1214, PA1218, PA11, PA12, preferably PA6, PA66, PA410, PA510, PA69, PA610, PA512, PA612, PA Selected from 514, PA614, PA618, PA1010, PA1012, PA1014, PA1018, PA1214, PA1218, PA11 and PA12, more preferably PA11 or PA12, and mixtures thereof.

[0171] Advantageously, the fibrous material present in the composite reinforcement layer of the single-layer structure defined above is selected from glass fibers, carbon fibers, basalt fibers, or basalt-based fibers.

[0172] In one embodiment, the single-layer structure defined above comprises one or more injection-molded inserts made of a semi-crystalline thermoplastic polymer, preferably an aliphatic polymer.

[0173] Multilayer structure In the second variation, the structure is a multilayer structure comprising at least two consecutive layers from the inside out. - At least one composite reinforcement layer as defined above, wherein the composite reinforcement layer is in contact with compressed gas, - At least one external composite reinforcement layer comprising a fibrous material in the form of continuous fibers impregnated with a composition mainly composed of at least one thermoplastic polymer, preferably semi-crystalline, Includes, The aforementioned composite material reinforcement layer and the aforementioned external composite material reinforcement layer are different. The outermost composite reinforcement layer is welded to the innermost composite reinforcement layer.

[0174] The impregnated fiber material constituting the external composite reinforcement layer has, after integration, the same or different lateral fracture strain as the impregnated fiber material constituting the composite reinforcement layer.

[0175] The thermoplastic polymer of the external composite reinforcement layer is as defined for the composite (and therefore internal) reinforcement layer.

[0176] Needless to say, the thermoplastic polymer of the composite reinforcement layer and the thermoplastic polymer of the external composite reinforcement layer are different. The term “different” is understood to mean that the two polymers are of different types, for example, one polymer is PEI and the other is selected from polyaryl ether ketone (PAEK), polyether ether ketone (PEEK), and polyether ketone ketone (PEKK), in particular polyether ether ketone (PEEK); or that the two polymers are of the same nature, for example, both polymers are polyamides, but one is aliphatic and the other is semi-aromatic, yet these two polymers are compatible, i.e., partially or completely miscible or react together; or that the two polymers are two different aliphatic polyamides or two different semi-aromatic polyamides; or that the fibrous materials are different in their properties and / or the number of fibers in the fibrous material.

[0177] The composition impregnated into the fibrous material of the external composite reinforcement layer may also include an impact resistance modifier and / or additives.

[0178] Additives can be selected from antioxidants, heat stabilizers, UV absorbers, light stabilizers, lubricants, inorganic fillers, flame retardants, nucleating agents, plasticizers, and dyes.

[0179] Advantageously, the composition impregnated into the fibrous material of the external composite reinforcement layer mainly consists of the thermoplastic polymer, 0-5% by weight of an impact modifier, and 0-5% by weight of an additive, with the total compositional components equal to 100% (based on a minimum of 90% thermoplastic polymer).

[0180] The composition impregnating the fibrous material of the composite reinforcement layer is different from the fibrous material of the outer composite reinforcement layer.

[0181] In one embodiment, the thermoplastic polymer into which the continuous fibers of the composite reinforcement layer of the above multilayer structure are impregnated is an aliphatic polyamide, particularly PA410, PA56, PA59, PA510, PA512, PA513, PA514, PA6, PA66, PA69, PA610, PA612, PA614, PA618, PA1010, PA1012, PApip10, PApip12, PA1014, PA1018, PA1210, PA1212, PA1214, PA1218, PA11, PA12, preferably PA6, PA66, PA410, PA510, PA69, PA610, PA512, PA612, PA514, PA614, PA618, PA1010, PA1012, PA1014, PA1018, PA1214, PA1218, PA11 and PA12, more preferably PA11 or PA12, and mixtures thereof are selected.

[0182] In the first variation of this embodiment, the thermoplastic polymer impregnated into the continuous fibers of the external composite reinforcement layer is an aliphatic polyamide, particularly PA410, PA56, PA59, PA510, PA512, PA513, PA514, PA6, PA66, PA69, PA610, PA612, PA614, PA618, PA1010, PA1012, PApip10, PApip12, PA1014, PA1018, PA1210, PA1212, PA1214, PA1218, PA11, PA12, preferably PA6, PA66, PA410, PA510, PA69, PA610, PA512, PA612, PA A thermoplastic polymer selected from 514, PA614, PA618, PA1010, PA1012, PA1014, PA1018, PA1214, PA1218, PA11 and PA12, more preferably PA11 or PA12, and mixtures thereof, which impregnates the continuous fibers of the composite reinforcement layer.

[0183] In the second variation of this embodiment, the thermoplastic polymer impregnating the continuous fibers of the external composite reinforcement layer is a semi-aromatic polyamide, in particular PA MPMDT / 6T, PA 11 / 10T, PA 11 / BACT, PA 5T / 10T, PA 11 / 6T / 10T, PA MXDT / 4T, PA MXDT / 6T, PA MXDT / 10T, PA MPMDT / 4T, PA MPMDT / 6T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 4T, PA BACT / 10T / 6T, PA 11 / BACT / 4T, PA 11 / BACT / 6T, PA 11 / BACT / 10T, PA 11 / MXDT / 4T, PA 11 / MXDT / 6T, PA 11 / MXDT / 10T, PA 11 / MPMDT / 4T, PA Selected from 11 / MPMDT / 6T, PA 11 / MPMDT / 10T, PA 11 / MXDT / 10T, PA11 / 5T / 10T, and mixtures thereof.

[0184] In another embodiment, the thermoplastic polymer impregnating the continuous fibers of the composite reinforcement layer of the multilayer structure is a semi-aromatic polyamide, in particular PA MPMDT / 6T, PA 11 / 10T, PA 11 / BACT, PA 5T / 10T, PA 11 / 6T / 10T, PA MXDT / 4T, PA MXDT / 6T, PA MXDT / 10T, PA MPMDT / 4T, PA MPMDT / 6T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 4T, PA BACT / 10T / 6T, PA 11 / BACT / 4T, PA 11 / BACT / 6T, PA 11 / BACT / 10T, PA 11 / MXDT / 4T, PA 11 / MXDT / 6T, PA 11 / MXDT / 10T, PA 11 / MPMDT / 4T, PA Selected from 11 / MPMDT / 6T, PA 11 / MPMDT / 10T, PA 11 / MXDT / 10T, PA11 / 5T / 10T, and mixtures thereof.

[0185] In the first variation of this other embodiment, the thermoplastic polymer impregnating the continuous fibers of the external composite reinforcement layer is an aliphatic polyamide, particularly PA410, PA56, PA59, PA510, PA512, PA513, PA514, PA6, PA66, PA69, PA610, PA612, PA614, PA618, PA1010, PA1012, PApip10, PApip12, PA1014, PA1018, PA1210, PA1212, PA1214, PA1218, PA11, PA12, preferably PA6, PA66, PA410, PA510, PA69, PA610, PA512, PA612, PA A thermoplastic polymer selected from 514, PA614, PA618, PA1010, PA1012, PA1014, PA1018, PA1214, PA1218, PA11 and PA12, more preferably PA11 or PA12, and mixtures thereof, which impregnates the continuous fibers of the composite reinforcement layer.

[0186] In a second variation of this other embodiment, the thermoplastic polymer impregnating the continuous fibers of the outer composite reinforcement layer is a semi-aromatic polyamide, in particular PA MPMDT / 6T, PA11 / 10T, PA11 / BACT, PA5T / 10T, PA 11 / 6T / 10T, PA MXDT / 4T, PA MXDT / 6T, PA MXDT / 10T, PA MPMDT / 4T, PA MPMDT / 6T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 4T, PA BACT / 10T / 6T, PA 11 / BACT / 4T, PA 11 / BACT / 6T, PA 11 / BACT / 10T, PA 11 / MXDT / 4T, PA 11 / MXDT / 6T, PA 11 / MXDT / 10T, PA 11 / MPMDT / 4T, PA Selected from 11 / MPMDT / 6T, PA 11 / MPMDT / 10T, PA 11 / MXDT / 10T, PA11 / 5T / 10T, and mixtures thereof.

[0187] In yet another embodiment, in the multilayer structure defined above, the thickness of the composite reinforcement layer is between 1% and 30% of the total thickness of the layers of the structure, more specifically between 1% and 10%, and even more preferably between 1% and 5%.

[0188] In yet another embodiment, in the multilayer structure defined above, the fiber volume content of the composite reinforcement layer is 30% to 50%, particularly 30% to 40%.

[0189] In yet another embodiment, in the multilayer structure defined above, the fiber content of the external composite reinforcement layer is 50% to 60% by volume, particularly 53% to 60% by volume, and particularly 53% to 57% by volume.

[0190] In yet another embodiment, in the multilayer structure defined above, the fiber volume content of the composite reinforcement layer is 30% to 50%, particularly 30% to 40%, and the fiber volume content of the outer composite reinforcement layer is 50% to 60%, particularly 53% to 60%, particularly 53% to 57%.

[0191] Advantageously, the fibrous material present in the composite reinforcement layer and the external composite reinforcement layer of the multilayer structure defined above is selected from glass fibers, carbon fibers, basalt fibers, or basalt-based fibers.

[0192] In one embodiment, the multilayer structure defined above comprises one or more injection-molded inserts made from a semicrystalline thermoplastic polymer, preferably an aliphatic polymer.

[0193] In one embodiment, the multilayer structure includes two layers.

[0194] In another embodiment, the multilayer structure comprises a composition mainly consisting of at least one thermoplastic polymer (preferably semicrystalline) and further includes at least one other layer positioned on top of the final outer composite reinforcement layer.

[0195] Advantageously, the thermoplastic polymer is particularly a semicrystalline polyamide.

[0196] In particular, the polyamide is selected from aliphatic polyamides and semi-aromatic polyamides.

[0197] Advantageously, the fibers in the composite reinforcement layer are stronger than the fibers in the external composite reinforcement layer.

[0198] In one embodiment, the fibers of the external composite reinforcement layer are fibers with a K of over 30K.

[0199] In another embodiment, the fibers in the composite reinforcement layer are fibers with a K of 30K or less.

[0200] In yet another embodiment, the fibers of the external composite reinforcement layer are fibers with a K of over 30K, and the fibers of the composite reinforcement layer are fibers with a K of 30K or less.

[0201] In one embodiment, the multilayer structure consists of three layers.

[0202] In yet another embodiment, the multilayer structure includes at least four layers. At least one composite reinforcement layer constituting the outer shell of the structure defined above, An external composite reinforcement layer comprising at least one fibrous material in the form of continuous fibers impregnated with a composition mainly composed of at least one thermoplastic polymer (preferably semicrystalline), The aforementioned composite material reinforcement layer and the aforementioned external composite material reinforcement layer are different. The outermost composite reinforcement layer is welded to the innermost composite reinforcement layer, An external composite reinforcement layer comprising at least one fibrous material in the form of continuous fibers impregnated with a composition mainly composed of at least a second thermoplastic polymer (preferably semicrystalline), The aforementioned composite material reinforcement layer and the aforementioned external composite material reinforcement layer are different. The second external composite reinforcement layer welded to the first external composite reinforcement layer, A composition comprising at least one thermoplastic polymer as the main component, preferably semi-crystalline, and at least a fourth layer positioned above the last outer layer of the second composite reinforcement layer. Includes.

[0203] In one embodiment, the fibers of the composite material reinforcement layer are fibers with a K of 30K or less.

[0204] In another embodiment, the fibers of the first external composite reinforcement layer are fibers with a K of 30K or less.

[0205] In yet another embodiment, the fibers of the second external composite reinforcement layer are fibers with a K of over 30K.

[0206] In yet another embodiment, the fibers of the composite material reinforcing layer are fibers with a K of 30K or less, and the fibers of the first composite material reinforcing layer are fibers with a K of 30K or less.

[0207] In yet another embodiment, the fibers of the composite reinforcement layer are 30K or less, and the fibers of the second external composite reinforcement layer are 30K or more.

[0208] In yet another embodiment, the fibers of the composite material reinforcing layer are 30K or less, the fibers of the first composite material reinforcing layer are 30K or less, and the fibers of the second external composite material reinforcing layer are 30K or more.

[0209] In one embodiment, the multilayer structure consists of four layers.

[0210] Advantageously, the thermoplastic polymer in the first layer is particularly a semicrystalline polyamide.

[0211] In particular, the polyamide in the first layer is selected from aliphatic polyamides and semi-aromatic polyamides, and is especially aliphatic polyamide.

[0212] Advantageously, the thermoplastic polymer in the second layer is particularly a semicrystalline polyamide.

[0213] In particular, the polyamide in the second layer is selected from aliphatic polyamides and semi-aromatic polyamides, with semi-aromatic polyamides being particularly preferred.

[0214] Advantageously, the thermoplastic polymer of the third layer is particularly a semicrystalline polyamide.

[0215] In particular, the polyamide of the third layer is selected from aliphatic polyamides and semi-aromatic polyamides, with semi-aromatic polyamides being particularly preferred.

[0216] Advantageously, the thermoplastic polymer of the fourth layer is particularly a semicrystalline polyamide.

[0217] In particular, the polyamide is selected from aliphatic polyamides and semi-aromatic polyamides.

[0218] In another embodiment, the present invention relates to a method for producing a single-layer or multi-layer structure as defined above, the method comprising at least one step of selecting a composite reinforcement layer constituting the outer skin of the structure, the composite reinforcement layer comprising a fibrous material in the form of continuous fibers impregnated with a composition mainly comprising at least one semi-crystalline ductile thermoplastic polymer, the impregnated fibrous material having, after integration, a lateral fracture strain greater than the fracture strain of the fibers at operating temperature and strain rate representative of use, particularly greater than 1.6%, particularly greater than 1.8%, particularly greater than 2%, and more particularly greater than 2.2%.

[0219] The step of selecting the composite reinforcement layer may include the following steps: - Selection of ductile thermoplastic polymer (or thermoplastic polymer resin), - Impregnation of a fibrous material with the ductile resin by one of the methods well known to those skilled in the art for obtaining a unidirectional (UD) ribbon, strip, or tape, - Preparation of composite reinforcement layers from the above ribbons, strips, or tapes, - Evaluation of the lateral fracture strain of the obtained composite reinforced layer. - Evaluation of the transverse fracture strain of the fibrous material (or fibers) before impregnation. - Selection of the composite reinforcement layer having a transverse fracture strain greater than the fracture strain of the fiber at the operating temperature and strain rate representative of use, particularly greater than 1.6%, particularly greater than 1.8%, particularly greater than 2%, and more particularly greater than 2.2%.

[0220] The selection of ductile polymer resins can be performed by determining the plasticity threshold that can be achieved by tensile testing of ISO 527-1BA test specimens.

[0221] Polymer resins considered suitable for the manufacture of ductile composites, i.e., composites having a lateral strain of more than 1.6%, particularly more than 1.8%, particularly more than 2%, and more specifically 2.2% at a temperature or strain rate representative of the use of the composite material, are selected when the plastic threshold at a temperature or strain rate representative of the use of the composite material is less than 120 MPa, particularly less than 85 MPa, particularly less than 60 MPa, and particularly less than 50 MPa.

[0222] The composite reinforcement layer can be produced, in particular, by filament winding using a unidirectional (UD) tape that is continuously deposited in layers on a heatable mandrel at one or more orientation angles with respect to the axis of the mandrel.

[0223] The evaluation of the lateral fracture strain of the obtained composite reinforced layer is performed as described above.

[0224] The evaluation of the lateral fracture strain of the fibrous material (or fibers) before impregnation is performed as described above.

[0225] Next, the composite reinforced layer is selected having a transverse fracture strain greater than the fracture strain of the fiber at the operating temperature and a strain rate representative of use, particularly greater than 1.6%, particularly greater than 1.8%, particularly greater than 2%, and more particularly greater than 2.2%.

[0226] In one embodiment, the method includes, after the selection step, a step of filament winding the impregnated fiber material.

[0227] In another embodiment, the method includes, after the filament winding step, welding the external composite reinforcement layer defined above onto the composite reinforcement layer.

[0228] The external reinforcing layer is wrapped around the outermost layer of the composite reinforcing layer and welded thereto by heating it using the heating system described in International Patent Application, International Publication No. 22 / 167757.

[0229] In another aspect, the present invention relates to the use of at least one composite reinforcement layer comprising a fibrous material in the form of continuous fibers impregnated with a composition mainly composed of at least one ductile thermoplastic polymer (preferably semicrystalline) having a glass transition temperature (Tg) measured according to standard ISO 11357-3:2013, wherein the Tg is less than or equal to the operating temperature To, or the Tg is higher than the operating temperature To, such that |To-Tg| ≤ +120°C, in particular |To-Tg| ≤ +80°C, in particular |To-Tg| ≤ +50°C. The composite reinforcement layer, after integration, has a lateral fracture strain greater than the fracture strain of the fibers, particularly greater than 1.6%, particularly greater than 1.8%, particularly greater than 2%, and more specifically greater than 2.2% at the operating temperature and strain rate representative of use as defined above. Preferably, for forming the outer covering of a single-layer or multi-layer structure for transporting, storing, or distributing compressed gas, particularly hydrogen, under high pressure, Regarding use.

[0230] In yet another aspect, the present invention relates to a method for using the single-layer or multi-layer structure defined above for transporting, storing, or distributing compressed gases, particularly hydrogen, preferably under high pressure. [Brief explanation of the drawing]

[0231] [Figure 1] The tensile curve obtained for polyamide 11 is shown: this test was interrupted in the plastic region, and the method for determining the elastic strain εe, plastic strain εp, and plastic threshold is shown. [Examples]

[0232] In all cases, the volume content of carbon fibers is determined by image analysis of the tape cross-section (particularly using a microscope, camera, or digital camera), by dividing the surface area of ​​the polymer-impregnated tape by the total surface area of ​​the product (sum of the impregnated surface area and the pore surface area). To obtain images of good quality, it is desirable to coat the transversely cut tape with a standard polishing resin and polish it using a standard protocol that allows the sample to be observed under a microscope at least 6x magnification.

[0233] Selection of a ductile matrix Several resin compositions (PA 11 / BACT / 10T and PA11) were synthesized by polycondensation, and then injected according to techniques well known to those skilled in the art to prepare ISO 527-1BA tensile test specimens.

[0234] Ductile polymer resins were selected by determining the plasticity threshold determined by tensile tests of these test specimens. Polymer resins providing ductile composites were selected if their plasticity threshold was less than 85 MPa at the temperature and strain rate representative of the intended use.

[0235] Selection of composition: PA 11 / BACT / 10T (Tg measured by DSC according to ISO 11357-3:2013 standard, 140°C), plastic threshold less than 85 MPa, operating temperature ≥ 85°C, and a strain rate of 10 representative of the selected application. -3 s -1 This applies to the case where...

[0236] PA11 (Tg 50°C measured by DSC according to standard ISO 11357-3:2013) is a strain rate representative of the selected use when the operating temperature is ≥ -60°C and the strain rate is 10 -3 s -1 In this case, it has a plasticity threshold of less than 85 MPa.

[0237] Next, after selecting a ductile matrix, a composite reinforcement layer was fabricated from a fibrous material pre-impregnated with thermoplastic resin (tape) in accordance with International Publication No. 2018 / 234 436 (according to Modified Example 2: strips of fibrous material (or tape) containing Hyosung H2550 carbon fiber impregnated with PA 11 / BACT / 10T (Arkema) or PA11 (Arkema)).

[0238] BAC corresponds to bis(aminomethyl)cyclohexane, and T corresponds to terephthalic acid.

[0239] The composite reinforcement layer was prepared by applying the tape prepared above by filament winding at a speed of 12 m / min on a mandrel using a robot equipped with a 1500W infrared heater.

[0240] The lateral fracture strain of the resulting composite reinforced layer is evaluated on a coupon. A 2 mm thick, 300 × 300 mm plate is composed of a stack of 16 unidirectional UD layers of impregnated fiber material, obtained by planar laser deposition followed by autoclave consolidation. From the obtained plate, a lateral tensile test specimen (T90°) is machined so that the fiber axis is perpendicular to the axis of the test specimen, and subjected to a strain rate of 10 -3 s -1 The tests were conducted at temperatures of -60°C, +23°C, and +85°C.

[0241] Next, the composite reinforced layer is selected having a transverse fracture strain greater than the fracture strain of the fiber at the operating temperature and a strain rate representative of use, particularly greater than 1.6%, particularly greater than 1.8%, particularly greater than 2%, and more particularly greater than 2.2%.

[0242] Following these laboratory tests on the coupons, various composite solutions were selected for manufacturing the tanks. To manufacture tanks to be used at operating temperatures To1 = +23°C and To2 = +85°C, a PA 11 composite material with a fiber content of 55 volume% was selected.

[0243] To manufacture tanks used at an operating temperature of To3 = -60°C, PA 11 composite material with a fiber content of 45% by volume was selected.

[0244] To manufacture tanks used at an operating temperature of To2 = +85°C, an 11 / BACT / 10T composite material with a fiber content of 40% by volume was selected.

[0245] Next, the following tank was prepared by filament winding on a mandrel. Example 1: A monolithic composite tank obtained by laminating a ductile PA11 matrix with a single type of composite layer having a carbon fiber content of 55 volume%.

[0246] The tank is used at operating temperatures To1 = 23°C = room temperature (RT) and |To1-Tg| = 27°C < 50°C.

[0247] The tank can also be used when T2 = 85°C > Tg (50°C).

[0248] This type of tank is tested under increasing pressure at each selected operating temperature. In both cases, no leaks are detected before the burst pressure is reached.

[0249] Example 2: The monolithic composite tank has a single layer of ductile PA11 matrix composite material and a carbon fiber content of 45 volume%, and the tank is used at operating temperatures To3 = -60°C and |To3-Tg| = 110°C < 120°C. It is also used at operating temperatures To>-60℃, in which case |To-Tg| is a function of this temperature value, either ≤120℃, ≤80℃, ≤50℃, or To>Tg.

[0250] This type of tank is tested under increasing pressure at each selected operating temperature. In all cases, no leaks are detected before the burst pressure is reached.

[0251] Example 3: The monolithic composite tank consists of two layers, a composite reinforcement layer (11 / BACT / 10T) with a low fiber content (40% by volume) to prevent microcracks and an external composite reinforcement layer (11 / BACT / 10T) with a high fiber content to achieve mechanical properties (55% by volume).

[0252] The tank is used at an operating temperature To2 = +85°C, |To2 - Tg| = 55°C < 80°C.

[0253] It is also used at an operating temperature To > +85°C. In this case, as a function of the value of this temperature, |To - Tg| ≤ 80°C or ≤ 50°C or To > Tg.

[0254] This type of tank is tested under increasing pressure at each selected operating temperature. In all cases, no leakage is detected before reaching the bursting pressure.

[0255] Example 4: The monolithic composite tank consists of two layers, an internal composite reinforcement layer (PA11) with a low fiber content (45% by volume ratio) to prevent microcracks and an external composite reinforcement layer (PA11 / BACT / 10T) with a high fiber content (55% by volume ratio) to achieve mechanical properties.

[0256] The tank is used at an operating temperature To3 = -60°C, |To3 - Tg| = 110°C < 120°C, and the Tg considered is the Tg of the matrix of the composite material constituting the internal layer of the tank.

[0257] The tank is also used at an operating temperature To > -60°C. In this case, as a function of the value of this temperature, |To - Tg| ≤ 120°C or ≤ 80°C or ≤ 50°C or To > Tg, and the Tg considered is the Tg of the matrix of the composite material constituting the internal layer of the tank.

[0258] This type of tank is tested under increasing pressure at each selected operating temperature. In all cases, no leakage is detected before reaching the bursting pressure.

[0259] Determination of the presence or absence of microcracks in the tanks of Examples 1-4.

[0260] The presence of microcracks was determined by detecting leaks before reaching or while maintaining the operating pressure, according to the following protocol. Leaks are detected by an underwater pressure test when the tank is pressurized to its operating pressure and / or when the pressure is maintained at the operating pressure.

[0261] The prepared tank is leak-free and therefore free of microcracks.

Claims

1. A single-layer or multi-layer structure, preferably a single-layer or multi-layer structure for transporting, storing, or distributing compressed gas, particularly hydrogen, under high pressure, The structure comprises at least one composite reinforcement layer constituting the outer skin of the structure, which is made of a fibrous material in the form of continuous fibers impregnated with a composition mainly composed of at least one semicrystalline ductile thermoplastic polymer having a glass transition temperature (Tg) measured according to standard ISO 11357-3:2013, wherein the Tg is less than or equal to the operating temperature To, or the Tg is higher than the operating temperature To, with |To-Tg| ≤ +120°C, in particular |To-Tg| ≤ +80°C, in particular |To-Tg| ≤ +50°C, and includes at least one composite reinforcement layer. The impregnated fiber material constituting the composite reinforcement layer, after integration, has a lateral fracture strain greater than the fracture strain of the fiber at the operating temperature and strain rate representative of use, particularly greater than 1.6%, particularly greater than 1.8%, particularly greater than 2%, and more particularly greater than 2.2%. The aforementioned structure does not include an internal sealing layer. A single-layer or multi-layered structure.

2. The single-layer or multilayer structure according to claim 1, characterized in that the thermoplastic polymer in the composite material reinforcement layer is a polyamide that is particularly semi-crystalline and has a C / N ratio of 5 or more, preferably 8 or more, particularly 9 or more, and more particularly 10 or more.

3. The continuous fibers of the composite reinforcement layer are impregnated with a particularly semicrystalline polyamide, which is an aliphatic polyamide, especially PA410, PA56, PA59, PA510, PA512, PA513, PA514, PA6, PA66, PA69, PA610, PA612, PA614, PA618, PA1010, PA1012, PApip10, PApip12, PA1014, PA1018, PA1210, PA1212, PA1214, PA1218, PA11, PA12, preferably PA6, PA66, PA410, PA510, PA69, PA610, PA512, PA612, PA A single-layer or multi-layer structure according to claim 2, characterized in that it is selected from 514, PA614, PA618, PA1010, PA1012, PA1014, PA1018, PA1214, PA1218, PA11 and PA12, more preferably PA11 or PA12, and mixtures thereof.

4. The continuous fibers of the composite reinforcement layer are impregnated with a particularly semi-crystalline polyamide, specifically a semi-aromatic polyamide, PA MPMDT / 6T, PA 11 / 10T, PA 11 / BACT, PA 5T / 10T, PA 11 / 6T / 10T, PA MXDT / 4T, PA MXDT / 6T, PA MXDT / 10T, PA MPMDT / 4T, PA MPMDT / 6T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 4T, PA BACT / 10T / 6T, PA 11 / BACT / 4T, PA 11 / BACT / 6T, PA 11 / BACT / 10T, PA 11 / MXDT / 4T, PA 11 / MXDT / 6T, PA A single-layer or multi-layer structure according to claim 2, characterized in that it is selected from 11 / MXDT / 10T, PA 11 / MPMDT / 4T, PA 11 / MPMDT / 6T, PA 11 / MPMDT / 10T, PA 11 / MXDT / 10T, PA11 / 5T / 10T, and mixtures thereof.

5. A single-layer or multi-layer structure according to any one of claims 1 to 4, characterized in that it is a single layer and includes at least one composite material reinforcing layer as described in claim 1.

6. The single-layer structure according to claim 5, characterized in that the fiber volume content of the at least one composite material reinforcing layer is 30% to 50% by volume, particularly 30% to 40% by volume.

7. It is a multilayered structure, consisting of at least two consecutive layers from the inside out, namely, - At least one composite material reinforcing layer as defined in claim 1, the composite material reinforcing layer in contact with compressed gas, - At least one external composite reinforcement layer comprising a fibrous material in the form of continuous fibers impregnated with a composition mainly composed of at least one thermoplastic polymer, preferably semi-crystalline, Includes, The aforementioned composite material reinforcement layer and the aforementioned external composite material reinforcement layer are different. The single-layer or multi-layer structure according to any one of claims 1 to 4, wherein the outermost composite reinforcement layer is welded to the innermost composite reinforcement layer.

8. The multilayer structure according to claim 7, characterized in that the thermoplastic polymer impregnated in the continuous fibers of the composite material reinforcement layer is as defined in claim 3.

9. The multilayer structure according to claim 8, characterized in that the thermoplastic polymer impregnating the continuous fibers of the outer reinforcing layer is as defined in claim 3 and is different from the thermoplastic polymer impregnating the continuous fibers of the composite material reinforcing layer.

10. The multilayer structure according to claim 8, characterized in that the thermoplastic polymer impregnating the continuous fibers of the external composite reinforcement layer is as defined in claim 4.

11. The multilayer structure according to claim 7, characterized in that the thermoplastic polymer impregnating the continuous fibers of the composite material reinforcement layer is as defined in claim 4.

12. The multilayer structure according to claim 11, characterized in that the thermoplastic polymer impregnating the continuous fibers of the external composite reinforcement layer is as defined in claim 3.

13. The multilayer structure according to claim 11, characterized in that the thermoplastic polymer impregnating the continuous fibers of the external composite reinforcement layer is as defined in claim 4.

14. A multilayer structure according to any one of claims 7 to 13, characterized in that the thickness of the composite reinforcement layer is between 1% and 30%, more specifically between 1% and 10%, and more preferably between 1% and 5%, relative to the total thickness of the layers of the structure.

15. A single-layer or multilayer structure according to any one of claims 1 to 14, characterized by comprising one or more injection-molded inserts made from a semi-crystalline thermoplastic polymer, preferably an aliphatic polymer.

16. A method for manufacturing a single-layer or multilayer structure according to any one of claims 1 to 15, comprising at least one step of selecting a composite reinforcement layer constituting the outer sheath of the structure, wherein the composite reinforcement layer consists of a fibrous material in the form of continuous fibers impregnated with a composition mainly comprising at least one semicrystalline ductile thermoplastic polymer, wherein, after integration, the impregnated fibrous material has a lateral fracture strain greater than the fracture strain of the fibers at the operating temperature and strain rate representative of use, particularly greater than 1.6%, particularly greater than 1.8%, particularly greater than 2%, and more particularly greater than 2.2%.

17. The method according to claim 16, characterized in that, after the selection step, the step includes winding the filaments of the fiber material.

18. The method according to claim 17, characterized in that, after the filament winding step, the step of welding the external composite reinforcement layer described in claim 5 onto the composite reinforcement layer.

19. The use of at least one composite reinforcement layer comprising a fibrous material in the form of continuous fibers impregnated with a composition mainly comprising at least one ductile thermoplastic polymer, preferably semicrystalline, having a glass transition temperature (Tg) measured according to standard ISO 11357-3:2013, wherein the Tg is less than or equal to the operating temperature To, or the Tg is higher than the operating temperature To, such that |To-Tg| ≤ +120°C, in particular |To-Tg| ≤ +80°C, in particular |To-Tg| ≤ +50°C. The composite reinforcement layer, after integration, has a lateral fracture strain greater than the fracture strain of the fibers, particularly at a strain rate representative of the operating temperature and application defined above, of more than 1.6%, particularly more than 1.8%, particularly more than 2%, and more specifically more than 2.2%. Preferably, it constitutes an outer covering of a single-layer or multi-layer structure for transporting, storing, or distributing compressed gas, particularly hydrogen, under high pressure. use.

20. Use of a single-layer or multi-layer structure according to any one of claims 1 to 15 for transporting, storing, or distributing compressed gas, particularly hydrogen, preferably under high pressure.

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