Multilayer structures for hydrogen storage

Abstract

A multilayer structure for hydrogen storage, comprising, from the inside out, at least one sealing layer (1) and at least one composite reinforcement layer (2), the innermost composite reinforcement layer being wound around the outermost adjacent sealing layer (1), and at least the innermost sealing layer being made of a composition comprising (relative to the total weight of the composition): a. 20.5 to 99.845 wt% of at least one polyamide; b. 0.005 to 0.5 wt% of at least one catalyst; c. 0.05 to 1 wt% of at least one heat stabilizer; d. 0.1 to 3 wt% of... At least one oligomer or polycarbodiimide; e. 0 to 1.5% by weight of at least one plasticizer; f. 0 to less than 15% by weight of at least one polyolefin, particularly 1 to less than 15% by weight of a polyolefin; g. 0 to 30% by weight of at least one additive, and at least one of the composite reinforcing layers is made of a fibrous material in the form of continuous fibers, impregnated with the composition, the composition mainly comprising at least one polymer P2j, particularly an epoxy resin or an epoxy-based resin, j = 1 to m, where m is the number of reinforcing layers.

Description

Technical Field

[0001] This patent application relates to a multilayer composite structure for hydrogen storage, and a method for manufacturing the same. Background Technology

[0002] Hydrogen tanks are currently attracting significant attention from numerous manufacturers, particularly in the automotive industry. One of the goals is to develop vehicles with increasingly lower emissions. Therefore, electric or hybrid vehicles, including batteries, are intended to gradually replace internal combustion engine vehicles such as gasoline or diesel cars. Batteries, however, prove to be relatively complex vehicle components. Depending on their location within the vehicle, protecting them from impacts and external environments with extreme temperatures and variable humidity is essential. Avoiding any fire risks is also necessary.

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

[0004] In addition, electric vehicles still suffer from several problems today, namely battery range, the use of rare earth metals in these batteries (the resources for which are not infinite), recharging time being much longer than the time required to fill the tank, and the electricity problems caused by battery recharging in various countries.

[0005] Therefore, hydrogen is an alternative to electric batteries because it can be converted into electricity through fuel cells, thereby powering electric vehicles.

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

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

[0008] The lining must have certain basic characteristics:

[0009] It can be transformed through extrusion blow molding, rotational molding or injection molding;

[0010] The low permeability to hydrogen is actually a key factor limiting hydrogen leakage from the tank.

[0011] It exhibits good mechanical properties (fatigue resistance) at low temperatures (-40℃ to -70℃);

[0012] Heat resistance at 120℃.

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

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

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

[0016] However, HDPE has the disadvantages of a low melting point and high hydrogen permeability, which presents new requirements for heat resistance and makes it impossible to increase the filling speed of the tank.

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

[0018] However, PA6 also has the disadvantage of low cold resistance.

[0019] WO2018155491 describes a hydrogen transport assembly with a three-layer structure, the inner layer of which is a composition consisting of PA11, 15 to 50% impact modifier, and 1 to 3% plasticizer, or without plasticizer, and the assembly possesses hydrogen barrier properties, good flexibility, and low-temperature durability. However, this structure is suitable for pipelines transporting hydrogen but not for pipelines storing hydrogen. Furthermore, the viscosity of the composition varies too much to be stabilized during conversion via extrusion blow molding, a conversion technology that can produce very high melt residence times (up to 20 minutes) within the aggregate at high temperatures.

[0020] Therefore, it remains necessary to: on the one hand, optimize the matrix of the composite to improve its mechanical strength at high temperatures; and on the other hand, optimize the materials constituting the sealing sheath to optimize its operating temperature. Thus, any optional modifications to the composition of the materials constituting the sealing liner must not result in a significant increase in the manufacturing temperature of the liner (extrusion blow molding, injection molding, rotational molding, etc.) compared to current practices.

[0021] These problems are addressed by providing the multilayer structure of the present invention, which is intended for hydrogen storage.

[0022] Throughout the instruction manual, the terms "lining" and "sealing sleeve" have the same meaning.

[0023] Therefore, the present invention relates to a multilayer structure intended for hydrogen storage, comprising, from the inside out, at least one sealing layer (1) and at least one composite reinforcement layer (2).

[0024] The innermost composite reinforcement layer is wrapped around the outermost adjacent sealing layer (1).

[0025] At least the innermost sealing layer consists of a composition comprising (relative to the total weight of the composition):

[0026] a. 20.5 to 99.845% by weight of at least one polyamide;

[0027] b. At least one catalyst, ranging from 0.005 to 0.5% by weight;

[0028] c. 0.05 to 1% by weight of at least one heat stabilizer;

[0029] d. 0.1 to 3% by weight of at least one oligomeric or polycarbodiimide;

[0030] e. 0 to 1.5% by weight of at least one plasticizer;

[0031] f. 0 to less than 15% by weight of at least one polyolefin;

[0032] g. 0 to 30% by weight of at least one additive,

[0033] The sum of components a to g is 100% by weight.

[0034] Furthermore, at least one of the composite reinforcing layers is composed of a fibrous material in the form of continuous fibers, impregnated with a composition that mainly comprises at least one polymer P2j, particularly an epoxy resin or an epoxy-based resin, where j = 1 to m, and m is the number of reinforcing layers.

[0035] Advantageously, the structure does not contain nucleating agents.

[0036] Advantageously, the structure does not have an outermost layer adjacent to the outermost layer of the polyamide polymer composite reinforcement layer.

[0037] Advantageously, the structure does not contain nucleating agents and has no outermost layer adjacent to the outermost polyamide polymer composite reinforcement layer.

[0038] Therefore, the inventors unexpectedly discovered that by using long-chain semi-crystalline polyamide thermoplastic polymers comprising limited proportions of impact modifiers and plasticizers, catalysts, heat stabilizers, and oligomers or polycarbodiimides, it is possible to obtain compositions for sealing layers that possess good viscosity—that is, a viscosity sufficiently high in the melt state to allow for conversion (particularly by extrusion blow molding) without increasing the viscosity in solution, in other words, intrinsic viscosity—and that the melt viscosity is sufficiently stable during conversion (particularly for extrusion blow molding). They also found that combinations of the sealing layer with different polymers (particularly epoxy or epoxy-based resins) for the composite matrix (with the composite wound around the sealing layer) can also yield structures suitable for hydrogen storage, particularly increasing the maximum operating temperature (up to 120°C), thereby improving the tank filling rate.

[0039] The term "multi-layered structure" should be understood to refer to a tank consisting of several layers or composed of several layers, namely, several sealing layers and several reinforcing layers, or one sealing layer and several reinforcing layers, or several sealing layers and one reinforcing layer, or one sealing layer and one reinforcing layer.

[0040] Therefore, this multi-layered structure should be understood as excluding pipes or tubes.

[0041] In one embodiment, the multilayer structure consists of two layers: a sealing layer and a reinforcing layer.

[0042] The one or more sealing layers are the innermost, compared to the outermost composite reinforcement layer.

[0043] The tank can be a tank for mobile storage of hydrogen (i.e., on a truck or a car used to transport hydrogen) and a tank for supplying hydrogen to fuel cells (e.g., on a train or a drone used to supply hydrogen), but it can also be a tank for static storage of hydrogen at a station used to distribute hydrogen to vehicles.

[0044] Advantageously, the sealing layer (1) is hydrogen-sealed at 23°C, i.e., at 0% relative humidity (RH), the hydrogen permeability at 23°C is less than 500 cc.mm / m2.24h.atm.

[0045] The composite reinforcement layer is wrapped around the sealing layer by a fiber strip (or tape or roving) impregnated with polymer, the polymer being deposited, for example, by filament winding.

[0046] When there are multiple layers, the polymers are different.

[0047] When the polymer of the reinforcing layer is the same, several layers may exist, but it is advantageous to have a single reinforcing layer, which has at least one complete wrap around the sealing layer.

[0048] This fully automated process, well known to those skilled in the art, allows for the selection of winding angles layer by layer, which gives the final structure the ability to withstand changes in internal pressure.

[0049] When there are several sealing layers, only the innermost sealing layer is in direct contact with hydrogen.

[0050] When there is only one sealing layer and one composite reinforcement layer, resulting in a multilayer structure of two layers, the two layers can adhere to each other and be in direct contact, especially since the composite reinforcement layer is wrapped around the sealing layer.

[0051] When there are several sealing layers and / or several composite reinforcement layers, the outermost sealing layer and therefore the layer opposite to the layer in contact with hydrogen may or may not adhere to the innermost layer of the composite reinforcement layer.

[0052] Other composite reinforcement layers may or may not be adhered to each other.

[0053] Other sealing layers may or may not adhere to each other.

[0054] Advantageously, there is only one sealing layer and one reinforcing layer, and they do not adhere to each other.

[0055] Advantageously, there is only one sealing layer and one reinforcing layer, which do not adhere to each other, and the reinforcing layer is composed of a fibrous material in the form of continuous fibers, impregnated with a composition that mainly comprises at least one polymer P2j, particularly an epoxy resin or an epoxy-based resin.

[0056] In one embodiment, there is only one sealing layer and one reinforcing layer, which are not adhered to each other, and the reinforcing layer is composed of a fibrous material in the form of continuous fibers, impregnated with a composition, the composition mainly comprising polymer P2j, which is an epoxy resin or an epoxy-based resin.

[0057] Throughout the specification, the term "epoxy-based" means that the epoxy component comprises at least 50% by weight of the matrix.

[0058] Regarding sealing layers and compositions

[0059] One or more sealing layers may be present.

[0060] There may be 1 to 10, especially 1 to 5, particularly 1 to 3 sealing layers, and preferably only 1 sealing layer.

[0061] At least the innermost sealing layer consists of a composition comprising (relative to the total weight of the composition):

[0062] a. 20.5 to 99.845% by weight of at least one polyamide;

[0063] b. At least one catalyst, ranging from 0.005 to 0.5% by weight;

[0064] c. 0.05 to 1% by weight of at least one heat stabilizer;

[0065] d. 0.1 to 3% by weight of at least one oligomeric or polycarbodiimide;

[0066] e. 0 to 1.5% by weight of at least one plasticizer;

[0067] f. 0 to less than 15% by weight of at least one polyolefin;

[0068] g. 0 to 30% by weight of at least one additive,

[0069] The sum of components a to g is 100% by weight.

[0070] In one embodiment, the composition comprises the following:

[0071] a. 20.5 to 99.845% by weight of at least one polyamide;

[0072] b. At least one catalyst, ranging from 0.005 to 0.5% by weight;

[0073] c. 0.05 to 1% by weight of at least one heat stabilizer;

[0074] d. 0.1 to 3% by weight of at least one oligomeric or polycarbodiimide;

[0075] e. 0 to 1.5% by weight of at least one plasticizer,

[0076] f. 0 to less than 15% by weight of at least one polyolefin;

[0077] g. 0 to 30% by weight of at least one additive,

[0078] The sum of components a to g is 100% by weight.

[0079] catalyst

[0080] The term "catalyst" refers to a polycondensation catalyst, such as a mineral acid or an organic acid.

[0081] The catalyst is present in a weight ratio of about 50 ppm to about 5000 ppm, particularly about 100 ppm to about 3000 ppm, relative to the total weight of the composition.

[0082] Advantageously, the catalyst is selected from phosphoric acid (H3PO4), phosphorous acid (H3PO3), hypophosphorous acid (H3PO2), or mixtures thereof.

[0083] Advantageously, the catalyst is present in a weight ratio of about 50 ppm to about 5000 ppm, particularly about 100 ppm to about 3000 ppm, relative to the total weight of the composition, and the catalyst is selected from phosphoric acid (H3PO4), phosphorous acid (H3PO3), hypophosphorous acid (H3PO2), or mixtures thereof.

[0084] Advantageously, the catalyst is selected from phosphoric acid (H3PO4) and phosphorous acid (H3PO3) in a ratio of about 100 ppm to about 3000 ppm.

[0085] Heat stabilizer:

[0086] Stabilizers can be organic stabilizers or more often combinations of organic stabilizers, such as primary phenolic antioxidants (e.g., Ciba's Irganox 245, 1098, or 1010), secondary phosphite (salt) antioxidants, and even optional other stabilizers, such as HALS (which stands for hindered amine light stabilizer, e.g., Ciba's Tinuvin 770), phenolic phosphite (salt) antioxidants (e.g., ... TL89), UV stabilizers (such as Ciba's Tinuvin 312), phenolic or phosphorus-based stabilizers. Amine antioxidants (such as Crompton's Naugard 445), or even multifunctional stabilizers (such as Clariant's Nylostab S-EED) may also be used.

[0087] The stabilizer can also be a mineral stabilizer, such as a copper-based stabilizer. Examples of such mineral stabilizers include halides and copper acetate. Alternatively, other metals, such as silver, can be considered, but these are known to be less effective. These copper-based compounds typically associate with alkali metal halides (especially potassium).

[0088] Advantageously, the heat stabilizer is an organic stabilizer.

[0089] The proportion of the heat stabilizer is from about 0.05% by weight to about 1% by weight, particularly from about 0.05% by weight to about 0.3% by weight, relative to the total weight of the composition.

[0090] Advantageously, the catalyst comprises about 50 ppm to about 5000 ppm, particularly about 100 ppm to about 3000 ppm, relative to the total weight of the composition, and the heat stabilizer comprises about 0.05 wt% to about 1 wt%, particularly about 0.05 wt% to about 0.3 wt%, relative to the total weight of the composition, and the catalyst is selected from phosphoric acid (H3PO4), phosphorous acid (H3PO3), hypophosphorous acid (H3PO2), or mixtures thereof.

[0091] Advantageously, the catalyst is selected from phosphoric acid (H3PO4) and phosphorous acid (H3PO3) in a ratio of about 100 ppm to about 3000 ppm.

[0092] Carbodiimide:

[0093] Carbodiimide refers to conventionally known carbodiimide polymers and oligomers, and can be prepared by the polymerization of diisocyanates.

[0094] This reaction can be accelerated by catalysts and by products that eliminate carbon dioxide (J.Org.Chem,28,2069(1963).J.Am.Chem.Soc.84,3673(1962);Chem.Rev.,81,589(1981);Ange.Chem.,93,855(1981)).

[0095] Reagents with NCO end groups may include reactive compounds with CH, NH, or OH groups, such as malonic acid, caprolactam, esters of alcohols or phenols.

[0096] Alternatively, a mixture of monoisocyanates and diisocyanates can be polymerized to obtain oligomers or polycarbodiimides containing substantially non-reactive end groups.

[0097] The carbodiimide used is an oligomeric or polycarbodiimide having the following general formula:

[0098] R1-N=C=N(-R2-N=C=N-)n-R3

[0099] R1 and R3 represent C1-C20 alkyl, C5-C20 cycloalkyl, aryl having 6 to 20 carbon atoms or aralkyl having 7 to 20 carbon atoms, each optionally substituted with an isocyanate group optionally comprising CH, NH or OH of the reactive compound;

[0100] R2 represents an alkylene group having 2 to 20 carbon atoms, a cycloalkylene group having 5 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkylene group having 7 to 20 carbon atoms.

[0101] n = 1 to 100, preferably 2 to 80, preferably 3 to 70.

[0102] Oligomeric or polycarbodiimide can be a homopolymer or copolymer, such as a copolymer of 2,4-diisocyanate-1,3,5-triisopropylbenzene and 1,3-diisocyanate-3,4-diisopropylbenzene.

[0103] The oligomeric or polycarbodiimide may also be selected from those described in US 5,360,888.

[0104] Suitable oligomers and polycarbodiimides are available from commercially available sources such as Rhein Chemie, Raschig, or Ziko.

[0105] Advantageously, the oligomeric or polycarbodiimide used is in the weight percentage of about 0.1% to about 3% by weight, particularly 0.5% to 2% by weight, particularly about 1% by weight, relative to the total weight of the composition.

[0106] Advantageously, the oligomer or polycarbodiimide is selected from Stabilizer, especially Especially in particular or Or a mixture thereof.

[0107] Therefore, advantageously, the present invention relates to the above-described structure comprising an innermost sealing layer consisting of a composition comprising (relative to the total weight of the composition): at least one catalyst, at least one heat stabilizer, and at least one oligomeric or polycarbodiimide in a proportion of about 0.1% to about 3% by weight, particularly 0.5% to 2% by weight, particularly about 1% by weight, relative to the total weight of the composition, wherein the matrix comprises at least one thermoplastic polymer, particularly polyamide, and the oligomeric or polycarbodiimide is selected from Stabilizers, particularly... Especially in particular or or mixtures thereof, and where appropriate, at least one plasticizer up to 1.5% by weight and / or at least one polyolefin up to 15% by weight.

[0108] Advantageously, the catalyst is present in a weight ratio of about 50 ppm to about 5000 ppm, particularly about 100 ppm to about 3000 ppm, relative to the total weight of the composition, and the oligomer or polycarbodiimide is present in a weight ratio of about 0.1 wt% to about 3 wt%, particularly 0.5 wt% to 2 wt%, particularly about 1 wt%, relative to the total weight of the composition, wherein the matrix comprises at least one thermoplastic polymer, particularly polyamide, the catalyst is selected from phosphoric acid (H3PO4), phosphorous acid (H3PO3), hypophosphorous acid (H3PO2) or mixtures thereof, and the oligomer or polycarbodiimide is selected from Stabilizer, particularly Especially in particular or Or a mixture thereof.

[0109] Advantageously, the catalyst is selected from phosphoric acid (H3PO4) and phosphorous acid (H3PO3) in a ratio of about 100 ppm to about 3000 ppm.

[0110] Advantageously, the proportion of the heat stabilizer is from about 0.05 wt% to about 1 wt%, particularly from about 0.05 wt% to about 0.3 wt%, relative to the total weight of the composition, and the proportion of the oligomeric or polycarbodiimide is from about 0.1 wt% to about 3 wt%, particularly from 0.5 wt% to 2 wt%, particularly about 1 wt%, relative to the total weight of the composition, and said oligomeric or polycarbodiimide is selected from Stabilizer, particularly Especially in particular or Or a mixture thereof.

[0111] Advantageously, the catalyst is present in a weight percentage of about 50 ppm to about 5000 ppm, particularly about 100 ppm to about 3000 ppm, relative to the total weight of the composition; the heat stabilizer is present in a weight percentage of about 0.05 wt% to about 1 wt%, particularly 0.05 wt% to 0.3 wt%, relative to the total weight of the composition; and the oligomeric or polycarbodiimide is present in a weight percentage of about 0.1 wt% to about 3 wt%, particularly 0.5 wt% to 2 wt%, particularly about 1 wt%, relative to the total weight of the composition. The catalyst is selected from phosphoric acid (H3PO4), phosphorous acid (H3PO3), hypophosphorous acid (H3PO2), or mixtures thereof, and the oligomeric or polycarbodiimide is selected from Stabilizers, particularly... in particular Especially or Or a mixture thereof.

[0112] Advantageously, the catalyst is selected from phosphoric acid (H3PO4) and phosphorous acid (H3PO3) in a ratio of about 100 ppm to about 3000 ppm.

[0113] additive:

[0114] The additives may be selected from another polymer, UV absorbers, light stabilizers, lubricants, inorganic fillers, flame retardants, dyes, carbon black and carbon nanofillers, excluding nucleating agents; in particular, the additives are selected from UV absorbers, light stabilizers, lubricants, inorganic fillers, flame retardants, dyes, carbon black and carbon nanofillers, excluding nucleating agents.

[0115] The other polymers may be other semi-crystalline thermoplastic polymers or different polymers, especially EVOH (ethylene vinyl alcohol).

[0116] In one embodiment, a single polyamide is present at least in the sealing layer that does not adhere to the composite reinforcement layer.

[0117] polyamide

[0118] Polyamides, especially semi-crystalline polyamides, particularly aliphatic or semi-aromatic polyamides, especially aliphatic polyamides.

[0119] Semi-crystalline polyamides are materials that are typically solid at ambient temperature, soften during temperature increases, particularly after exceeding their glass transition temperature (Tg), exhibit a rapid transformation above their so-called melting point (Tm), and become solid again when the temperature drops below their crystallization temperature.

[0120] Tg, Tc, and Tm were determined by differential scanning calorimetry (DSC) according to standards 11357-2:2013 and 11357-3:2013, respectively.

[0121] The number-average molecular weight (Mn) of the semi-crystalline polyamide is preferably in the range of 10,000 to 85,000, particularly 10,000 to 60,000, more preferably 10,000 to 50,000, and even more preferably 12,000 to 50,000. These Mn values ​​can correspond to an intrinsic viscosity greater than or equal to 0.8, as determined in m-cresol according to standard ISO 307:2007, but by changing the solvent (using m-cresol instead of sulfuric acid, and at a temperature of 20°C).

[0122] The nomenclature used to define polyamides is described in ISO standard 1874-1:2011 “Plastiques--Matériaux polyamides(PA)pour moulage et extrusion--Partie 1:Désignation”, particularly on page 3 (Tables 1 and 2), and is well known to those skilled in the art.

[0123] Polyamides can be homopolymers, copolymers, or mixtures thereof.

[0124] In one embodiment, the polyamide is an aliphatic polyamide, particularly a long-chain aliphatic polyamide, that is, a polyamide with an average number of carbon atoms per nitrogen atom greater than 8.5, preferably greater than 9, and particularly greater than 10.

[0125] Specifically, the long-chain aliphatic polyamide is selected from:

[0126] Polyamide 10 (PA10), polyamide 11 (PA11), polyamide 12 (PA12), polyamide 1010 (PA1010), polyamide 1012 (PA1012), polyamide 1212 (PA1212) or mixtures thereof or copolyamides thereof, particularly PA11 and PA12.

[0127] More particularly, polyamide 11 (PA11), polyamide 12 (PA12), polyamide 1012 (PA1012), polyamide 1212 (PA1212) or mixtures thereof or copolyamides thereof, especially PA11 and PA12.

[0128] In one embodiment, the long-chain aliphatic polyamide is selected from:

[0129] Polyamide 12 (PA12), polyamide 1010 (PA1010), polyamide 1012 (PA1012), polyamide 1212 (PA1212) or mixtures thereof or copolyamides thereof, especially PA12.

[0130] In another embodiment, the long-chain aliphatic polyamide is selected from:

[0131] Polyamide 12 (PA12), polyamide 1012 (PA1012), polyamide 1212 (PA1212) or mixtures thereof or copolyamides thereof, especially PA12.

[0132] In another embodiment, said semi-crystalline polyamide thermoplastic polymer is a semi-aromatic semi-crystalline polyamide, particularly a long-chain semi-aromatic semi-crystalline polyamide, that is, a polyamide having an average number of carbon atoms per nitrogen atom greater than 8.5, preferably greater than 9, particularly greater than 10, and a melting point from 240°C to less than 280°C.

[0133] In particular, said long-chain semi-aromatic semi-crystalline polyamide is selected from polyamide 11 / 5T, 11 / 6T, 11 / 10T, MXDT / 10T, <PMDT / 10T and BACT / 10T.

[0134] Advantageously, each sealing layer is composed of a composition comprising the same type of polyamide.

[0135] If welding is necessary, there are various methods allowing welding of elements made of polyamide thermoplastic polymer. Thus, contact or non-contact heating blades, ultrasound, infrared, vibration, rotation of one element to be welded against another element, or even laser welding may be used.

[0136] About polyolefins

[0137] In one embodiment, PEBA is excluded from the definition of polyolefins.

[0138] The polyolefin may be functionalized or non-functionalized, or a mixture of at least one functionalized polyolefin and / or at least one non-functionalized polyolefin. For simplicity, the polyolefin is denoted as (B), and functionalized polyolefin (B1) and non-functionalized polyolefin (B2) are described hereinafter.

[0139] Non-functionalized polyolefin (B2) is generally a homopolymer or copolymer of α-olefins or diolefins (such as ethylene, propylene, 1-butene, 1-octene, butadiene). By way of example, there may be mentioned:

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

[0141] - homopolymers or copolymers of propylene.

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

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

[0144] - A copolymer of ethylene with at least one of the following: a salt or ester of an unsaturated carboxylic acid (e.g., an alkyl methacrylate, such as methyl acrylate) or a vinyl ester of a saturated carboxylic acid (e.g., vinyl acetate (EVA)), wherein the proportion of comonomers may reach 40% by weight.

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

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

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

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

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

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

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

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

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

[0154] The functionalized polyolefin (B1) may also be a copolymer or terpolymer of at least the following units: (1) ethylene, (2) alkyl esters of (meth)acrylate or vinyl esters of saturated carboxylic acids, and (3) anhydrides, such as maleic anhydride, or (meth)acrylate or epoxy resins, such as glycidyl methacrylate.

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

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

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

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

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

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

[0161] In addition, the aforementioned polyolefin (B1) can also be crosslinked by any suitable method or reagent (diepoxy, diacid, peroxide, etc.); the term functionalized polyolefin also includes a mixture of the aforementioned polyolefin with a bifunctional reagent (e.g., diacid, dianhydride, diepoxy, etc.) that can react with them, or a mixture of at least two functionalized polyolefins that can react together.

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

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

[0164] Advantageously, the nonfunctionalized polyolefin (B2) is selected from homopolymers or copolymers of polypropylene, and any ethylene homopolymer, or ethylene copolymers comonomers with higher α-olefins (e.g., butene, hexene, octene, or 4-methyl-1-pentene). Examples of PE include PP, high-density PE, medium-density PE, linear low-density PE, low-density PE, and very low-density PE. Those skilled in the art know that these polyethylenes are prepared according to a "free radical" method, a "Ziegler" catalytic method, or the more recently so-called "metallocene" catalytic method.

[0165] Advantageously, the functionalized polyolefin (B1) is selected from any polymer comprising α-olefin units and units having polar reactive functional groups (e.g., epoxy, carboxylic acid, or carboxylic anhydride functional groups). Examples of such polymers include: ethylene, alkyl acrylates, and maleic anhydride or glycidyl methacrylate (e.g., the applicant's). terpolymers of maleic anhydride, or polyolefins grafted with maleic anhydride (e.g., SK Chemicals's). ), and terpolymers of ethylene, alkyl acrylate and (meth)acrylic acid. Homopolymers or copolymers of polypropylene grafted with carboxylic anhydrides and then condensed with polyamide or monoamine polyamide oligomers may also be mentioned.

[0166] Advantageously, the composition constituting the sealing layer is free of polyether block amide (PEBA). In this embodiment, PEBA is therefore excluded from the polyolefin.

[0167] Regarding plasticizers:

[0168] The plasticizer may be a plasticizer commonly used in polyamide-based compositions.

[0169] Advantageously, plasticizers with good thermal stability are used, such that they do not generate fumes during the steps of mixing and converting different polymers to obtain the composition.

[0170] Specifically, the plasticizer can be selected from:

[0171] Benzenesulfonamide derivatives, such as the ortho and para isomers of n-butylbenzenesulfonamide (BBSA), ethyl toluenesulfonamide (ETSA), N-cyclohexyl toluenesulfonamide, and N-(2-hydroxypropyl)benzenesulfonamide (HP-BSA),

[0172] Esters of hydroxybenzoic acid, such as 2-ethylhexyl p-hydroxybenzoate (EHPB) and 2-decyl hexyl p-hydroxybenzoate (HDPB),

[0173] Esters or ethers of tetrahydrofurfuryl alcohol, such as oligoethyleneoxytetrahydrofurfuryl alcohol, and

[0174] Esters of citric acid or hydroxymalonic acid, such as oligoethylene oxymalonic acid ester.

[0175] The preferred plasticizer is n-butylbenzenesulfonamide (BBSA).

[0176] Another more particularly preferred plasticizer is N-(2-hydroxypropyl)benzenesulfonamide (HP-BSA). In fact, the latter has the advantage of preventing the formation of deposits (“die drooling”) at the extruder screw and / or die during the extrusion deformation step.

[0177] Of course, a mixture of plasticizers can also be used.

[0178] In one embodiment, the composition of the at least one innermost sealing layer comprises at least one polyolefin in a proportion of 1% to less than 15% by weight, particularly 1% to 12% by weight, particularly 1% to 10% by weight, relative to the total weight of the composition.

[0179] In one embodiment, the composition does not contain plasticizers.

[0180] In one embodiment, the composition of the at least one innermost sealing layer comprises at least one polyolefin in a proportion of 1% to less than 15% by weight, particularly 1% to 12% by weight, particularly 1% to 10% by weight, relative to the total weight of the composition, and the composition is free of plasticizers.

[0181] In yet another embodiment, the composition of the at least one innermost sealing layer comprises at least one polyolefin in a proportion of 1% to less than 15% by weight, particularly 1% to 12% by weight, particularly 1% to 10% by weight, relative to the total weight of the composition, and 0.1% to 1.5% by weight of a plasticizer, relative to the total weight of the composition.

[0182] Regarding the composite reinforcement layer and polymer P2j

[0183] Polymer P2j can be a thermoplastic polymer or a thermosetting polymer.

[0184] One or more composite reinforcement layers may exist.

[0185] Each of the layers is composed of a fibrous material in the form of continuous fibers, impregnated with a composition that primarily comprises at least one thermoplastic polymer P2j, where j corresponds to the number of layers present.

[0186] j includes 1 to 10, especially 1 to 5, especially 1 to 3, and preferably j = 1.

[0187] The term "major" means that the at least one polymer is present in an amount of more than 50% by weight, relative to the total weight of the composition and the composite matrix.

[0188] Advantageously, the at least one major polymer is present in an amount of more than 60% by weight, particularly more than 70% by weight, especially more than 80% by weight, and even more particularly more than or equal to 90% by weight, relative to the total weight of the composition.

[0189] The composition may further include impact modifiers and / or additives.

[0190] Impact modifier

[0191] Impact modifiers are advantageously composed of polymers that have a flexural modulus of less than 100 MPa and a Tg of less than 0 °C (measured at the inflection point of a DSC thermogram according to standard 11357-2), particularly polyolefins.

[0192] Polyolefins are defined as described above.

[0193] The additives in the composition of the composite reinforcing layer can be selected from antioxidants, heat stabilizers, UV absorbers, light stabilizers, lubricants, inorganic fillers, flame retardants, plasticizers and dyes, excluding nucleating agents.

[0194] Advantageously, the composition consists primarily of the thermoplastic polymer P2j, 0 to 15% by weight of an impact modifier, particularly 0 to 12% by weight of an impact modifier, and 0 to 5% by weight of an additive, the sum of which is equal to 100 by weight.

[0195] The at least one main polymer in each layer may be the same or different.

[0196] In one embodiment, a single primary polymer is present at least in the composite reinforcement layer and does not adhere to the sealing layer.

[0197] In one embodiment, each reinforcing layer comprises the same type of polymer, particularly epoxy resin or epoxy-based resin.

[0198] Polymer P2j

[0199] thermoplastic polymer P2j

[0200] Thermoplastic materials or thermoplastic polymers refer to materials that are generally solid at ambient temperatures, which may be semi-crystalline or amorphous, especially semi-crystalline, and when the material is amorphous, it softens and flows at higher temperatures during temperature increases, particularly after exceeding its glass transition temperature (Tg), or when the material is semi-crystalline, it exhibits a rapid transformation upon passing its so-called melting point (Tm), and when the temperature is lowered below the material's crystallization temperature Tc (for semi-crystalline materials) and below its glass transition temperature (for amorphous materials), the material becomes solid again.

[0201] Tg, Tc, and Tm were determined by differential scanning calorimetry (DSC) according to standards 11357-2:2013 and 11357-3:2013, respectively.

[0202] When the thermoplastic polymer corresponds to polyamide, its number-average molecular weight Mn is preferably in the range of 10,000 to 40,000, more preferably 10,000 to 30,000. These Mn values ​​may correspond to an intrinsic viscosity greater than or equal to 0.8, as determined in m-cresol according to standard ISO 307:2007, but by changing the solvent (using m-cresol instead of sulfuric acid, and at a temperature of 20°C).

[0203] Examples of suitable semi-crystalline thermoplastic polymers in this invention include:

[0204] Polyamides, particularly those comprising aromatic and / or alicyclic structures, including copolymers such as polyamide-polyether copolymers; polyesters;

[0205] Polyaryletherketone (PAEK);

[0206] Polyetheretherketone (PEEK);

[0207] Polyetherketoneketone (PEKK);

[0208] Polyetherketoneketone (PEKEKK);

[0209] Polyimides, especially polyetherimides (PEI) or polyamide-imides;

[0210] Polysulfone (PSU), especially polyarylsulfone, such as polyphenylsulfone (PPSU);

[0211] Polyethersulfone (PES).

[0212] More particularly preferred are semi-crystalline polymers, especially polyamides and their semi-crystalline copolymers.

[0213] The nomenclature used to define polyamides is described in ISO standard 1874-1:2011 “Plastiques--Matériaux polyamides(PA)pour moulage et extrusion--Partie 1:Désignation”, particularly on page 3 (Tables 1 and 2), and is well known to those skilled in the art.

[0214] Polyamides can be homopolymers, copolymers, or mixtures thereof.

[0215] Advantageously, the semi-crystalline polyamide is a semi-aromatic polyamide, particularly a semi-aromatic polyamide of formula X / YAr as described in EP1505099, especially a semi-aromatic polyamide of formula A / XT, wherein A is selected from units obtained from amino acids, units obtained from lactams, and units corresponding to the formula (Ca diamine).(Cb diacid), wherein a represents the number of carbon atoms in the diamine, b represents the number of carbon atoms in the diacid, and a and b are each between 4 and 36, advantageously between 9 and 18, the unit (Ca diamine) is selected from linear or branched aliphatic diamines, alicyclic diamines, and alkyl aromatic diamines, and the unit (Cb diacid) is selected from linear or branched aliphatic diacids, alicyclic diacids, and aromatic diacids;

[0216] XT represents a unit obtained by the polycondensation of Cx diamine and terephthalic acid, where x represents the number of carbon atoms in the Cx diamine, x being between 5 and 36, advantageously between 9 and 18, particularly polyamides having the formula A / 5T, A / 6T, A / 9T, A / 10T or A / 11T (A as defined above), especially polyamides selected from: PA MPMDT / 6T, PA11 / 10T, PA 5T / 10T, PA11 / BACT, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA 11 / BACT / 6T, PA 11 / MPMDT / 6T, PA 11 / MPMDT / 10T, PA 11 / BACT / 10T, PA 11 / MXDT / 10T, PA 11 / 5T / 10T.

[0217] T corresponds to terephthalic acid, MXD corresponds to m-phenylenediamine, MPMD corresponds to methylpentamethylenediamine, and BAC corresponds to bis(aminomethyl)cyclohexane. The semi-aromatic polyamides defined above particularly have a Tg greater than or equal to 80°C.

[0218] The expression “stable during conversion” means that the melt viscosity changes by no more than 70% over time, particularly between 1 minute (the time required to melt the product) and at least 30 minutes, especially between 1 minute and 30 minutes.

[0219] Advantageously, the melt viscosity of the composition of the innermost sealing layer is substantially constant for up to 20 minutes.

[0220] "Substantially constant" should be understood as meaning that the melt viscosity does not change by more than 20% over a period of up to 20 minutes, between 1 minute and at least 5 minutes, and especially between 1 minute and 5 minutes.

[0221] Advantageously, the composition also has resistance to thermal oxidation.

[0222] The characteristic used to describe “thermal oxidation resistance” is the material’s half-life (in hours). This corresponds to the time it takes for the initial elongation at break to be halved after the ISO 527-2 1BA specimen has been aged in air at 140°C, as measured by standard ISO 527-2 (2012).

[0223] Advantageously, the thermal oxidation resistance is at least 80 days, especially 100 days.

[0224] Advantageously, the melt viscosity of the composition is from about 13,000 Pa·s to about 23,000 Pa·s, which is determined by oscillatory rheology at 270°C, as defined above.

[0225] Melt viscosity was measured on a Physica MCR301 instrument between two parallel plates with a diameter of 25 mm, at 5% deformation and 10 seconds. -1 Shear strength was determined by oscillatory rheology at 270 °C and 10 rad / sec under nitrogen purging.

[0226] The intrinsic viscosity was measured according to standard ISO 307:2007, but m-cresol was used instead of sulfuric acid, and the temperature was 20°C.

[0227] thermosetting polymer P2j

[0228] Thermosetting polymers are selected from epoxy resins or epoxy-based resins, polyesters, vinyl esters and polyurethanes, or mixtures thereof, particularly epoxy resins or epoxy-based resins.

[0229] Advantageously, each composite reinforcing layer is composed of a composition containing the same type of polymer, particularly epoxy resin or epoxy-based resin.

[0230] The composition containing the polymer P2j is transparent to radiation suitable for welding.

[0231] In another embodiment, the composite reinforcement layer is wrapped around the sealing layer without any subsequent welding.

[0232] About the structure

[0233] Therefore, the multilayer structure includes a sealing layer and at least one composite reinforcement layer wrapped around the sealing layer and may or may not adhere to each other.

[0234] Advantageously, the sealing layer and the reinforcing layer do not adhere to each other and are composed of compositions comprising different polymers respectively.

[0235] Nevertheless, the different polymers may be of the same type.

[0236] Therefore, if one of the two composite reinforcing layers and sealing layers is composed of a composition containing aliphatic polyamides, the other layer is composed of a composition containing non-aliphatic polyamides, such as semi-aromatic polyamides, thereby having a high Tg polymer as the matrix of the composite reinforcing layer.

[0237] The multilayer structure may include up to 10 sealing layers and up to 10 composite reinforcement layers of different properties.

[0238] Obviously, the multilayer structure does not have to be symmetrical, so it may include more sealing layers than composite layers or vice versa, but the sealing layers and reinforcing layers may not alternate.

[0239] Advantageously, the multilayer structure includes one, two, three, four, five, six, seven, eight, nine, or ten sealing layers, and one, two, three, four, five, six, seven, eight, nine, or ten composite reinforcing layers.

[0240] Advantageously, the multilayer structure includes one, two, three, four or five sealing layers, and one, two, three, four or five composite reinforcement layers.

[0241] Advantageously, the multilayer structure includes one, two, or three sealing layers and one, two, or three composite reinforcement layers.

[0242] Advantageously, they consist of compositions that each contain different polymers.

[0243] Advantageously, they consist of compositions comprising polyamide, particularly semi-crystalline polyamide, especially aliphatic or aromatic polyamide, and epoxy or epoxy resin P2j.

[0244] In one embodiment, the multilayer structure includes a single sealing layer and a plurality of reinforcing layers, with adjacent reinforcing layers wrapped around the sealing layer and other reinforcing layers wrapped around directly adjacent reinforcing layers.

[0245] In another embodiment, the multilayer structure includes a single reinforcing layer and several sealing layers, the reinforcing layer being wound around the adjacent sealing layers.

[0246] In an advantageous embodiment, the multilayer structure includes a single sealing layer and a single composite reinforcement layer wrapped around the sealing layer.

[0247] Therefore, all combinations of these two layers are within the scope of this invention, provided that at least the innermost composite reinforcing layer is wrapped around the outermost adjacent sealing layer, and the other layers are either adhered to each other or not adhered to each other.

[0248] Advantageously, in the multilayer structure, each sealing layer is composed of a composition comprising the same type of polyamide, particularly semi-crystalline polyamide, particularly aliphatic polyamide, particularly long-chain or semi-aromatic polyamide, particularly long-chain polyamide.

[0249] The expression "the same type of polyamide" means, for example, polyamides that may be the same or different depending on the layers.

[0250] Advantageously, the polyamide is a semi-crystalline polyamide, particularly an aliphatic polyamide, especially a long-chain or semi-aromatic polyamide, particularly a long-chain polyamide, and the polymer P2j is an epoxy resin or an epoxy resin.

[0251] In the first variant, the polyamide is a semi-crystalline polyamide, particularly an aliphatic polyamide, especially a long-chain polyamide, and the polymer P2j is an epoxy resin or an epoxy-based resin.

[0252] In the second variant, the polyamide is a semi-aromatic polyamide, particularly a long-chain polyamide, and the polymer P2j is an epoxy resin or an epoxy-based resin.

[0253] Advantageously, the polyamide is the same for all sealing layers.

[0254] Advantageously, the semi-crystalline polyamide is a long-chain aliphatic polyamide, particularly PA1010, PA1012, PA1212, PA11, PA12, especially PA11 or PA12.

[0255] Advantageously, the polyamide is a long-chain semi-aromatic polyamide, particularly PA 11 / 5T, PA 11 / 6T, or PA 11 / 10T. Obviously, in this case, the content of amino group 11 in the copolyamide must be carefully selected so that the Tm of the polymer is below 280°C, preferably 265°C.

[0256] Advantageously, in the multilayer structure, each reinforcing layer is composed of a composition comprising the same type of polymer P2j, particularly epoxy resin or epoxy-based resin.

[0257] Advantageously, polyamide P2j is the same for all reinforcing layers.

[0258] Advantageously, in the multilayer structure, each sealing layer is composed of a composition containing the same type of polyamide, particularly semi-crystalline polyamide, and each reinforcing layer is composed of a composition containing the same type of polymer P2j, particularly epoxy resin or epoxy-based resin.

[0259] Advantageously, the polyamide is a long-chain aliphatic semi-crystalline polyamide, particularly PA1010, PA1012, PA1212, PA11, PA12, especially PA11 or PA12, and the polymer P2j is a semi-aromatic semi-crystalline polyamide, particularly selected from PAMPMDT / 6T, PA11 / 10T, PA11 / BACT, PA5T / 10T, PA11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA11 / BACT / 6T, PA11 / MPMDT / 6T, PA11 / MPMDT / 10T, PA11 / BACT / 10T, PA11 / MXDT / 10T.

[0260] In one embodiment, the multilayer structure comprises a single reinforcing layer and a single sealing layer, wherein the polyamide is a long-chain aliphatic semi-crystalline polyamide, particularly PA1010, PA1012, PA1212, PA11, PA12, especially PA11 or PA12, and the polymer P2j is a semi-aromatic polyamide, particularly selected from PA MPMDT / 6T, PA11 / 10T, PA 11 / BACT, PA 5T / 10T, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA 11 / BACT / 6T, PA 11 / MPMDT / 6T, PA 11 / MPMDT / 10T, PA 11 / BACT / 10T, and PA 11 / MXDT / 10T.

[0261] In yet another embodiment, the multilayer structure comprises a single reinforcing layer and a single sealing layer, wherein the polymer P1i is a long-chain aliphatic semi-crystalline polyamide (particularly PA1010, PA1012, PA1212, PA11, PA12), or a semi-aromatic semi-crystalline polyamide (particularly selected from polyamide 11 / 5T or 11 / 6T or 11 / 10T, MXDT / 10T, MPMDT / 10T and BACT / 10T, particularly PA11 or PA12), and the polymer P2j is an epoxy resin or an epoxy-based resin.

[0262] Advantageously, the multilayer structure further includes at least one outer layer composed of a fibrous material made of continuous glass fibers impregnated with a transparent amorphous polymer, the outermost layer of the multilayer structure.

[0263] The outer layer is a second enhancement layer, but it is transparent, which allows text to be placed on the structure.

[0264] Regarding fibrous materials

[0265] Regarding the fibers constituting the fibrous material, they are in particular mineral fibers, organic fibers, or plant fibers.

[0266] Advantageously, the fibrous material may be sizing or unsizing.

[0267] Therefore, the fibrous material may contain up to 3.5% by weight of organic material (thermosetting or thermoplastic resin type), referred to as sizing.

[0268] Mineral fibers include, for example, carbon fibers, glass fibers, basalt or basalt-based fibers, silica fibers, or silicon carbide fibers. Organic fibers include fibers based on thermoplastic or thermosetting polymers, such as semi-aromatic polyamide fibers, aromatic polyamide fibers, or polyolefin fibers. Preferably, they are based on amorphous thermoplastic polymers and have a glass transition temperature Tg higher than their Tg when the polymer or thermoplastic polymer mixture constituting the preimpregnated matrix is ​​amorphous, or a glass transition temperature Tg higher than their Tm when the polymer or thermoplastic polymer mixture constituting the preimpregnated matrix is ​​semi-crystalline. Advantageously, they are based on semi-crystalline thermoplastic polymers and have a melting temperature Tm higher than their Tg when the polymer or thermoplastic polymer mixture constituting the preimpregnated matrix is ​​amorphous, or a melting temperature Tm higher than their Tm when the polymer or thermoplastic polymer mixture constituting the preimpregnated matrix is ​​semi-crystalline. Therefore, the organic fibers constituting the fibrous material do not pose a risk of melting during impregnation with the thermoplastic matrix of the final composite material. Among naturally derived plant fibers, those based on flax, hemp, lignin, bamboo, silk, and other cellulose-based fibers (especially viscose-based fibers) are mentioned. These plant fibers can be used in pure, treated, or coated forms to facilitate adhesion and impregnation with the thermoplastic polymer matrix.

[0269] Fibrous materials can also be fabrics woven or spun from fibers.

[0270] It can also correspond to fibers with support lines.

[0271] These component fibers can be used alone or in mixtures. Thus, organic fibers can be mixed with mineral fibers to preimpregnate them with thermoplastic polymer powder and form preimpregnated fibrous materials.

[0272] Organic fiber bundles can have a certain weight. They can also have a number of geometries. The component fibers of fibrous materials can also take the form of mixtures of these reinforcing fibers with different geometries. These fibers are continuous fibers.

[0273] Preferably, the fibrous material is selected from glass fiber, carbon fiber, basalt fiber or basalt-based fiber, or mixtures thereof, especially carbon fiber.

[0274] It is used in the form of one or more shares.

[0275] According to another aspect, the present invention relates to a method for producing a multilayer structure as defined above, characterized in that the method includes the step of preparing a sealing layer by extrusion blow molding, rotational molding or half-shell injection molding.

[0276] In one embodiment, the method of producing the multilayer structure includes the step of winding reinforcing filaments as defined above around a sealing layer as defined above.

[0277] All the features described in detail above also apply to this method. Attached Figure Description Example

[0278] In all embodiments, the can is obtained by rotational molding of the sealing layer (lining) at a temperature suitable for the properties of the thermoplastic resin used.

[0279] Example:

[0280] Products used

[0281] The polyamide used is (BESNO, sold by Arkema)

[0282] Heat stabilizer is NDB TL89: A phenolic phosphite organic stabilizer sold by Chemtura.

[0283] The carbodiimide used was sold by Raschig. (poly-di(1,3,5-triisopropylphenyl)carbodiimide).

[0284] The catalyst used is H3PO3 or H3PO4.

[0285] BBSA: n-Butylbenzenesulfonamide sold by PROVIRON

[0286] EXXELOR VA1801: A polyolefin (maleic anhydride-functionalized ethylene-propylene copolymer) sold by Exxon.

[0287] Example 1: Evaluation of the composition of the present invention: melt viscosity and heat resistance at 140°C.

[0288] The proportions shown are weight percentages relative to the total weight of the composition.

[0289] The test was conducted on a twin-screw extruder (Coperion ZSK40, which has two screws with a diameter of 40 mm and a length corresponding to 40 times their diameter) at 280°C, 300 rpm, 600 mmHg vacuum, and at a speed of 60 kg / h.

[0290] The PA substrate is dry (moisture content <0.1%).

[0291] The compositions of the present invention (Inv) and the comparative compositions (Comp) are presented in Table 1.

[0292] [Table 1]

[0293]

[0294] Example 2: Comparison of the properties of the composition according to the present invention with comparative composition 1

[0295] Liners made of PA11 prepared by rotational molding of comparative compositions 1 (Comp.1) and 2 (Comp.2) as well as compositions 1 and 2 (Inv.1 and Inv.2) of the present invention.

[0296] Hydrogen permeability is determined by the following method: the upper surface of the membrane is purged with a test gas (hydrogen), and the flow rate through the membrane in the lower portion of the membrane purged with carrier gas nitrogen is measured by gas chromatography.

[0297] The experimental conditions are shown in Table 2, and the results are shown in Table 3.

[0298] [Table 2]

[0299] Detection Chromatography (TCD) column Poraplot Q(L=27.5m, Dint=0.530mm, Ep. membrane=20μ) carrier gas Nitrogen Diffused gas Hydrogen (U(H2)) Test surface area <![CDATA[50cm 2 ]]> calibration Absolute calibration is performed via direct injection through the diaphragm. Pressure at the column head 18psi Oven temperature Isothermal 30℃ Detector temperature 200℃ detector: TCD[-] syringe temperature Temperature of Iyssy injection circuit Temperature / Relative Humidity 23℃ / 0%RH

[0300] [Table 3]

[0301] Comp1 <![CDATA[371cc.mm / m 2 .24h.atm]]> Comp2 <![CDATA[480cc.mm / m 2 .24h.atm]]> Inv.1 <![CDATA[265cc.mm / m 2 .24h.atm]]> Inv.2 <![CDATA[290cc.mm / m 2 .24h.atm]]>

[0302] The results in Table 3 show that the linings prepared from the compositions of the present invention (Inv.1 and Inv.2) have low hydrogen permeability.

[0303] Example 3: Notched Charpy impact strength at -30°C, according to ISO 179-1:2010.

[0304] The same lining as in Example 2 was prepared by rotational molding.

[0305] These linings were subjected to notched simply supported beam impact strength tests at -30°C.

[0306] The impact strength results of the notched simply supported beam are shown in Table 4.

[0307] [Table 4]

[0308] Inv.1 10kJ / m2 Inv.2 10kJ / m2 Comp1 7kJ / m2 Comp2 6kJ / m2

[0309] PA11 liners without plasticizer or with 1.5% by weight plasticizer have greater cold resistance than PA11 liners with 6% by weight plasticizer or 12% by weight plasticizer.

Claims

1. A multilayer structure intended for hydrogen storage, comprising, from the inside out, at least one sealing layer (1) and at least one composite reinforcement layer (2), The innermost composite reinforcement layer is wrapped around the outermost adjacent sealing layer (1). At least the innermost sealing layer is composed of a composition comprising the following, by weight of the total composition: a. 20.5 to 99.845% by weight of at least one polyamide; b. At least one catalyst, ranging from 0.005 to 0.5% by weight; c. At least one heat stabilizer, ranging from 0.05% to 1% by weight; d. 0.1 to 3% by weight of at least one oligomeric or polycarbodiimide; e. 0 to 1.5% by weight of at least one plasticizer; f. 0 to less than 15% by weight of at least one polyolefin; g. 0 to 30% by weight of at least one additive, The sum of the contents of all components in the composition is equal to 100% by weight. Furthermore, at least one of the composite reinforcing layers is composed of a fibrous material in the form of continuous fibers, impregnated with a composition, the composition mainly comprising at least one polymer P2j, j = 1 to m, where m is the number of composite reinforcing layers.

2. The multi-layer structure according to claim 1, characterized in that, The innermost sealing layer is composed of a composition comprising, by weight of, at least one polyolefin, from 1 to 15% by weight of the total weight of the composition.

3. The multi-layer structure according to claim 1, characterized in that, The fibrous material is impregnated with a composition, which mainly comprises an epoxy resin.

4. The multi-layer structure according to claim 1, characterized in that, Each sealing layer contains the same type of polyamide.

5. The multi-layer structure according to claim 1, characterized in that, Each composite reinforcement layer contains the same type of polymer.

6. The multi-layer structure according to claim 5, characterized in that, Each composite reinforcing layer contains the same type of polymer selected from epoxy resins.

7. The multi-layer structure according to any one of claims 4 to 6, characterized in that, Each sealing layer contains the same type of polyamide, and each composite reinforcement layer contains the same type of polymer.

8. The multi-layer structure according to claim 7, characterized in that, Each composite reinforcing layer contains the same type of polymer selected from epoxy resins.

9. The multilayer structure according to any one of claims 1 to 6, characterized in that, The multi-layer structure has a single sealing layer and a single composite reinforcement layer.

10. The multi-layer structure according to claim 1, characterized in that, The polyamide in the innermost sealing layer is a long-chain aliphatic polyamide or a semi-aromatic polyamide.

11. The multi-layer structure according to claim 10, characterized in that, The long-chain aliphatic polyamide is selected from PA1010, PA1012, PA1212, PA11, or PA12.

12. The multi-layer structure according to claim 11, characterized in that, The long-chain aliphatic polyamide is selected from PA 11 or PA 12.

13. The multi-layer structure according to claim 10, characterized in that, The semi-aromatic polyamide is selected from polyamide 11 / 5T, 11 / 6T, 11 / 10T, MXDT / 10T, MPMDT / 10T or BACT / 10T.

14. The multi-layer structure according to claim 1, characterized in that, The polymer P2j is an epoxy resin.

15. The multilayer structure according to any one of claims 10 to 14, characterized in that, The multilayer structure consists of a single composite reinforcing layer and a single sealing layer, wherein the polyamide of the single sealing layer is a long-chain aliphatic polyamide or a semi-aromatic polyamide, and the polymer P2j is an epoxy resin.

16. The multi-layer structure according to claim 15, characterized in that, The long-chain aliphatic polyamide is selected from PA1010, PA1012, PA1212, PA11, or PA12.

17. The multi-layer structure according to claim 15, characterized in that, The semi-aromatic polyamide is selected from polyamide 11 / 5T, 11 / 6T, 11 / 10T, MXDT / 10T, MPMDT / 10T or BACT / 10T.

18. The multi-layer structure according to claim 15, characterized in that, The polyamide of the single sealing layer is selected from PA11 or PA12.

19. The multilayer structure according to any one of claims 1 to 6, characterized in that, The melt viscosity of the composition of the innermost sealing layer is substantially constant up to 20 minutes.

20. The multilayer structure according to any one of claims 1 to 6, characterized in that, The composition of the innermost sealing layer also has thermal oxidation resistance.

21. The multilayer structure according to any one of claims 1 to 6, characterized in that, The composition of the innermost sealing layer has a melt viscosity of 13,000 to 23,000 Pa·s, which, when deformed by 5% and 10 sec between two parallel plates with a diameter of 25 mm, yields a viscosity that is suitable for use in applications requiring 10 seconds of contact with the surrounding surface. -1 Shear strength was determined by oscillatory rheology at 270 °C and 10 rad / sec under nitrogen purging.

22. The multilayer structure according to any one of claims 1 to 6, characterized in that, The fibrous material of the composite reinforcement layer is selected from glass fiber, carbon fiber, basalt-based fiber, or a mixture thereof.

23. The multi-layer structure according to claim 22, characterized in that, The fibrous material of the composite reinforcement layer is selected from carbon fiber.

24. The multilayer structure according to any one of claims 1 to 6, characterized in that, The multilayer structure further includes at least one outer layer composed of a fibrous material made of continuous glass fibers and impregnated with a transparent amorphous polymer. The at least one outer layer composed of a fibrous material is the outermost layer of the multilayer structure. The fibrous material is made of continuous glass fibers and impregnated with a transparent amorphous polymer.

25. The method for producing a multilayer structure according to any one of claims 1 to 24, characterized in that, The method includes the steps of preparing the sealing layer by extrusion blow molding, rotational molding, injection molding, or extrusion.

26. The method for producing a multi-layered structure according to claim 25, characterized in that, The method includes the step of preparing the sealing layer by reactive extrusion.

27. The method for producing a multi-layered structure as described in claim 25 or 26, characterized in that, The method includes the step of winding the composite reinforcing layer filament as described in any one of claims 1 to 24 around the sealing layer as described in any one of claims 1 to 24.

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