Multilayer structure and article for storing and transporting gas

Abstract

A multi-layer structure suitable for the manufacture of articles for storing and transporting gases, in particular pressure vessels, is disclosed. The container is particularly adapted to store and transport compressed gas in a vehicle.

Description

[0001] Citation of Related Applications

[0002] This application claims the benefit of priority of U.S. Provisional Application No. 63 / 387,314, filed Dec. 14, 2022, and European Patent Application No. 23158670.2, filed Feb. 27, 2023, the entire contents of each of which are hereby incorporated by reference for all purposes. Technical Field

[0003] The present invention relates to a multi-layer structure suitable for manufacturing articles adapted to store and transport gases, in particular pressure vessels. The present invention further relates to an article comprising such multi-layer structure, such as a pressure vessel. The present invention further relates to a method for manufacturing a pressure vessel. Background Art

[0004] Pressure vessels characterized by high gas barrier properties have been used for storing various gases such as oxygen, carbon dioxide, nitrogen, argon, LPG (liquefied petroleum gas), methane, and hydrogen for long periods of time. Such pressure vessels are known to include a non-structural inner layer or liner surrounded by a composite material reinforced with structural fibers to contain a fluid or gas under pressure. The liner acts as a barrier between the fluid or gas and the fiber-reinforced composite material, thereby preventing leakage and / or other degradation of the structure of the fiber-reinforced composite material. The use of a composite material reinforced with structural fibers containing a thermoplastic polymer matrix facilitates the reuse of the pressure vessel. Pressure vessels comprising a polyamide-based inner liner and an outer layer, which is a composite material containing continuous fibers and a polyamide resin impregnated into the continuous fibers, are disclosed, for example, in EP 3225888 A1, EP 3390016 A1, and WO 21152254 A1.

[0005] However, there is still a need to develop articles for transporting and storing hydrogen and generally gases, in particular pressure vessels, which combine high performance qualities in terms of impermeability to the stored gas, mechanical properties at both low and high temperatures, and high thermal degradation temperature, for ease of processing. An additional advantage of the present application is the non-flammability of the pressure vessel.

[0006] Accordingly, it is an object of the present invention to provide articles, such as pressure vessels, which have a very low permeability to gases, such as hydrogen, and good mechanical tolerance over a wide temperature range without the use of a structural layer made of metal or other non-thermoplastic polymer materials. This object is achieved by the multi-layer structure of the present invention. Summary of the Invention

[0007] Accordingly, a first object of the present invention is a multilayer structure comprising at least one barrier layer [layer (BL)] and at least one composite material layer [layer (CL)] in contact with the at least one barrier layer, wherein:

[0008] - layer (BL) comprises a poly(arylene sulfide) polymer; and

[0009] - layer (CL) comprises continuous reinforcing fibers and a poly(arylene sulfide) polymer.

[0010] A second object of the present invention is an article for storing or transporting a gas, the article comprising the multilayer structure of the first object. Layer (BL) represents the inner layer of the article in contact with the gas stored or transported (hereinafter also referred to as the "inner layer" or "liner"), while layer (CL) represents the outer layer of the article. The article may be a container, preferably a pressure vessel, i.e., a container for storing a gas under pressure.

[0011] A third object of the present invention is a compressed gas in a container, the container comprising the multilayer structure of the first object, wherein layer (BL) is in contact with the compressed gas. A further object of the present invention is a method for manufacturing the container and the use of the container in a vehicle. Detailed Description

[0012] In the present application:

[0013] - Any description given even with respect to a specific embodiment is applicable to and interchangeable with other embodiments of the present disclosure;

[0014] - When an element or component is said to be included in and / or selected from a list of recited elements or components, it is understood that in the relevant embodiments specifically contemplated herein, the element or component may also be any one of these recited individual elements or components, or may also be selected from a group consisting of any two or more of the recited elements or components; any element or component recited in the list of elements or components may be omitted from this list;

[0015] - Any recitation of a numerical range by endpoints herein includes all numbers included within the recited range as well as the endpoints and equivalents thereof;

[0016] - The indefinite article "a" in expressions like "a poly(arylene sulfide) polymer" is intended to mean "one or more", or "at least one", unless otherwise indicated; and

[0017] - The use of parentheses "()" before and after the name, symbol or number of a compound, such as "layer (BL)", "layer (CL)", etc., has the sole purpose of better differentiating that name, symbol or number from the rest of the text; thus, said parentheses may also be omitted.

[0018] A first object of the present invention is a multi-layer structure comprising at least one barrier layer [layer (BL)] and at least one composite layer [layer (CL)] in contact with said at least one barrier layer, wherein:

[0019] - Layer (BL) comprises a poly(arylene sulfide) polymer; and

[0020] - Layer (CL) comprises continuous reinforcing fibers and a poly(arylene sulfide) polymer.

[0021] Poly(arylene sulfide) polymer

[0022] Layer (BL) and layer (CL) comprise a poly(arylene sulfide) polymer. The poly(arylene sulfide polymer) in layer (BL) may be the same as or different from the poly(arylene sulfide) polymer in layer (CL).

[0023] When there is more than one layer (BL), each layer (BL) may comprise the same or different poly(arylene sulfide) polymers, preferably the same poly(arylene sulfide) polymer.

[0024] When there is more than one layer (CL), each layer (CL) may comprise the same or different poly(arylene sulfide) polymers, typically the same poly(arylene sulfide) polymer.

[0025] The poly(arylene sulfide) polymer typically contains at least 50.0 mol% of repeating units (R PAS ), said repeating units having at least one aromatic ring bonded to a sulfur atom. In some embodiments, the amount of repeating units (R PAS ) is at least 60.0 mol%, at least 70.0 mol%, at least 80.0 mol%, at least 90.0 mol%, at least 95.0 mol%, at least 97.0 mol%, at least 98.0 mol%, at least 99.0 mol% or at least 99.9 mol%. As used herein, unless otherwise expressly stated, mol% is relative to the total number of repeating units in the poly(arylene sulfide) polymer.

[0026] The repeating units (R PAS ) are represented by a formula selected from the group consisting of the following formulas:

[0027]

[0028] Wherein:

[0029] -R is independently selected in each case from the group consisting of: C1-C 12 alkyl, C7-C 24 alkylaryl, C7-C 24 aralkyl, C6-C 24 arylene and C6-C 18 aryloxy;

[0030] -T is selected from the group consisting of: a bond, -CO-, -SO2-, -O-, -C(CH3)2, phenyl and -CH2-;

[0031] -i is independently in each case an integer of 0 or 1 to 4; and

[0032] -j is independently in each case an integer of 0 or 1 to 3.

[0033] For the sake of clarity, when i or j is zero, the corresponding aromatic ring is unsubstituted.

[0034] Unless otherwise expressly indicated, the term "alkyl" as used herein and derivative terms such as "alkoxy" and "alkylaryl" include straight-chain, branched-chain and cyclic moieties within their scope. Examples of alkyl are methyl, ethyl, 1-methylethyl, propyl, 1,1-dimethylethyl and cyclopropyl. Unless otherwise expressly stated, each alkyl and aryl may be unsubstituted or substituted by one or more substituents selected from, but not limited to, the following: halogen, hydroxy, sulfo, C1-C6 alkoxy, C1-C6 alkylthio, C1-C6 acyl, formyl, cyano, C6-C15 aryloxy or C6-C15 aryl, provided that these substituents are sterically compatible and satisfy the rules of chemical bonding and strain energy. The term "halogen" or "halo" includes fluorine, chlorine, bromine and iodine, with fluorine being preferred.

[0035] The term "aryl" refers to phenyl, indanyl or naphthyl. An aryl may contain one or more alkyl groups and in such cases is sometimes referred to as "alkylaryl"; for example, it may be composed of a cyclic aromatic group and two C1-C6 groups (such as methyl or ethyl). An aryl may also contain one or more heteroatoms (e.g., N, O or S) and is sometimes referred to as "heteroaryl"; these heteroaromatic rings may be fused to other aromatic systems. Such heteroaromatic rings include, but are not limited to, furyl, thienyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, isoxazolyl, oxazolyl, thiazolyl, isothiazolyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl and triazinyl ring structures. An aryl or heteroaryl substituent may be unsubstituted or substituted with one or more substituents selected from, but not limited to, the following: halogen, hydroxy, C1-C6 alkoxy, sulfo, C1-C6 alkylthio, C1-C6 acyl, formyl, cyano, C6-C15 aryloxy or C6-C15 aryl, provided that these substituents are sterically compatible and satisfy the rules of chemical bonding and strain energy.

[0036] The poly(arylene sulfide) polymer can be amorphous or semi-crystalline. As used herein, an amorphous polymer has a melting enthalpy of no more than 5 J / g. One of ordinary skill in the art will recognize that when the poly(arylene sulfide) polymer is amorphous, it has no detectable melting temperature. Thus, when the poly(arylene sulfide) polymer has a melting temperature, one of ordinary skill in the art will recognize that it refers to a semi-crystalline polymer. Preferably, the poly(arylene sulfide) polymer is semi-crystalline. In some embodiments, the poly(arylene sulfide) polymer has a melting enthalpy of at least 10 J / g, at least 20 J / g, or at least 25 J / g. In some embodiments, the poly(arylene sulfide) polymer has a melting enthalpy of no more than 90 J / g, no more than 70 J / g or no more than 60 J / g. In some embodiments, the poly(arylene sulfide) polymer has a melting enthalpy of 10 J / g to 90 J / g or 20 J / g to 70 J / g. The melting enthalpy can be measured using differential scanning calorimetry (DSC) with a heating and cooling rate of 20 °C / min according to ASTM D3418. Advantageously, three scans are used for each DSC test: first heating to 350 °C, then first cooling to 30 °C, and then second heating to 350 °C.

[0037] Preferably, the poly(arylene sulfide) polymer has a melt flow rate of at most 700 g / 10 min, more preferably at most 500 g / 10 min. Preferably, the poly(arylene sulfide) has a melt flow rate of at least 1 g / 10 min, more preferably at least 5 g / 10 min. In this specification, the melt flow rate of any poly(arylene sulfide) polymer refers to the value measured at 5 kg and 315.6 °C as detailed in the experimental section.

[0038] As noted above, each layer of the multi-layer structure comprises a poly(arylene sulfide) polymer.

[0039] According to an embodiment of the present invention, the poly(arylene sulfide) polymer is poly(phenylene sulfide) (hereinafter also referred to as "PPS"). The expression "poly(phenylene sulfide)" or PPS is used to refer to a poly(arylene sulfide) polymer in which the repeating unit (R PAS ) is represented by formula (1). More preferably, the repeating unit (R PAS ) is represented by formula (4):

[0040]

[0041] More preferably, in PPS, the repeating unit (R PAS ) is represented by formula (4) where i = 0.

[0042] The PPS can be acid-washed or non-acid-washed. In some embodiments, the PPS is acetic acid-washed PPS.

[0043] In a preferred embodiment, the PPS polymer is such that at least 90.0 mol% of the repeating units are the repeating units of formula (4) where i = 0. The PPS polymer can consist essentially of the repeating units of formula (4) where i = 0.

[0044] Suitable PPS is available from Solvay Specialty Polymers USA, LLC under the trade name The PPS is commercially available.

[0045] The melt flow rate of the PPS (at 5 kg and 315.6 °C) can be from 1 to 400 g / 10 min, such as from 5 to 300 g / 10 min or from 5 to 200 g / 10 min.

[0046] Layer (BL)

[0047] Layer (BL) is configured to provide a barrier to gas permeation.

[0048] Layer (BL) does not contain any continuous reinforcing fibers.

[0049] The layer (BL) has a thickness that provides the required gas permeability value for the application. The layer (BL) typically has a thickness of at least 100 microns, usually at least 250 microns. The layer (BL) can have a thickness of up to 10.0 mm, even 8.5 mm, 7.5 mm. The layer (BL) can have a thickness of 100 microns to 10.0 mm, usually 250 microns to 10.0 mm, even 300 microns to 8.5 mm, still 500 microns to 6.0 mm.

[0050] In the first embodiment, the poly(arylene sulfide) polymer is the only polymer in the layer (BL). In such an embodiment, the layer (BL) contains 75.0 wt% or more, even 80.0 wt% or more, still 85.0 wt% or more of poly(arylene sulfide) relative to the total weight of the layer (BL). In such an embodiment, the layer (BL) can contain 25.0 wt% or less of one or more additives typically employed in the formulation of poly(arylene sulfide) polymers. Non-limiting examples of suitable additives are antioxidants (such as UV stabilizers and heat stabilizers), processing aids, nucleating agents, lubricants, flame retardants, smoke suppressants, antistatic agents, anti-caking agents, colorants, and pigments.

[0051] The total amount of additives can be 20.0 wt% or less, even 10.0 wt% or less relative to the total weight of the layer (BL). When present, the amount of one or more additives is at least 1.0 wt%, even at least 2.0 wt% relative to the total weight of the poly(aryl sulfide) polymer.

[0052] In a preferred aspect of the said embodiment, the poly(arylene sulfide) polymer is PPS.

[0053] The PPS suitable for the layer (BL) advantageously has a melt flow rate (at 5 kg and 315.6 °C) of 5 to 200 g / 10 min, for example 5 to 180 g / 10 min. In some instances, the melt flow rate can be 5 to 50 g / 10 min, even 5 to 40 g / 10 min.

[0054] In the second embodiment, the layer (BL) contains a poly(arylene sulfide) polymer, preferably PPS, and at least one other thermoplastic polymer.

[0055] In an advantageous aspect of the said embodiment, the layer (BL) contains a poly(arylene sulfide) polymer, preferably PPS, and an impact modifier.

[0056] Suitable impact modifiers are, for example, functionalized polyolefins having a glass transition temperature below 25 °C.

[0057] The polymer backbone of the impact modifier can be selected from elastomeric backbones, which include polyethylene and its copolymers, such as ethylene-butene; ethylene-octene; polypropylene and its copolymers; polybutene; polyisoprene; ethylene-propylene rubber (EPR); ethylene-propylene-diene monomer rubber (EPDM); ethylene-acrylate rubber; butadiene-acrylonitrile rubber, ethylene-acrylic acid (EAA), ethylene-vinyl acetate (EVA); acrylonitrile-butadiene-styrene rubber (ABS), block copolymer styrene-ethylene-butylene-styrene (SEBS); block copolymer styrene-butadiene-styrene (SBS); core-shell elastomers of the methacrylate-butadiene-styrene (MBS) type, or a mixture of one or more of the above.

[0058] When the impact modifier is functionalized, the functionalization of the backbone can be produced by copolymerization with a functionalized monomer, or by grafting the polymer backbone with another component.

[0059] Specific examples of functionalized impact modifiers are notably terpolymers of ethylene, acrylate and glycidyl methacrylate, copolymers of ethylene and butyl acrylate; copolymers of ethylene, butyl acrylate and glycidyl methacrylate; ethylene-maleic anhydride copolymers; EPR grafted with maleic anhydride; styrene copolymers grafted with maleic anhydride; SEBS copolymers grafted with maleic anhydride; styrene-acrylonitrile copolymers grafted with maleic anhydride; ABS copolymers grafted with maleic anhydride.

[0060] Functionalized polyolefin impact modifiers are commercially available, including maleated polypropylene and ethylene-propylene copolymers (available as PO) and maleic anhydride-functionalized ethylene-propylene copolymer rubbers containing approximately 0.6 weight percent of side-attached succinic anhydride groups, such as VA 1801 from ExxonMobil Chemical Company; acrylate-modified polyethylene available as such as 9920, acrylic or methacrylic acid-modified polyethylene from Dow Inc.; maleic anhydride-modified SEBS block copolymers, such as FG1901X, SEBS grafted with approximately 2 wt% maleic anhydride, available from Kraton Polymers; maleic anhydride-functionalized EPDM terpolymer rubbers, such as 498, 1% maleic anhydride-functionalized EPDM, available from SI Group.

[0061] Other desired functionalized impact modifiers include, but are not limited to, ethylene - higher α - olefin polymers and ethylene - higher α - olefin - diene polymers grafted or copolymerized with reactive carboxylic acids or their derivatives such as acrylic acid, methacrylic acid, maleic anhydride or their esters. Suitable higher α - olefins include, but are not limited to, C3 to C8 α - olefins such as propylene, 1 - butene, 1 - hexene and styrene.

[0062] Among the reactive impact modifiers, mention may be made of the random terpolymer of ethylene, acrylate and glycidyl methacrylate, commercially available under the trade name AX8900 from Arkema (Bristol, Pennsylvania, USA). Another example of the above - mentioned reactive impact modifier is the core - shell acrylate - based impact modifier commercially available under the trade name Paraloid TM EXL 2314 from Dow (Midland, Michigan, USA), which is a core - shell acrylate - based impact modifier comprising a core mainly composed of cross - linked poly(n - butyl acrylate) rubber and having a shell phase mainly composed of a poly(methyl methacrylate) - poly(glycidyl methacrylate) copolymer.

[0063] In the second embodiment, layer (BL) comprises from 1.0 wt% to 25.0 wt% of at least one thermoplastic polymer and / or impact modifier, relative to the total weight of layer (BL). The impact modifier can be at least 2.0 wt% or at least 3.0 wt%, or even at least 5.0 wt% of the total weight of layer (BL). The impact modifier typically does not exceed 20.0 wt%, does not exceed 15.0 wt%, does not exceed 12.0 wt%, or even does not exceed 10.0 wt%. Suitable ranges can be, for example, 1.0 to 15.0 wt%, or even 1.0 to 12.0 wt%, or even 2.0 to 10.0 wt%.

[0064] In the second embodiment, layer (BL) may additionally comprise additives as detailed above. The total amount of additives can be 20.0 wt% or less, or even 10.0 wt% or less, relative to the total weight of layer (BL) and / or at least 1.0 wt%, or even at least 2.0 wt%, relative to the total weight of layer (BL).

[0065] Layer (BL) can be prepared using common techniques for manufacturing films or sheets of poly(phenylene sulfide) polymers, as known to those skilled in the art. For example, layer (BL) can be produced by rotational molding, injection molding and optionally welding, pipe extrusion and extrusion blow molding.

[0066] The film of poly(phenylene sulfide) polymer can optionally be uniaxially or biaxially oriented. Biaxial orientation can be carried out on a tenter frame biaxial orientation device as known in the art.

[0067] Layer (CL)

[0068] The multi-layer structure of the present invention comprises at least one layer (CL). The layer (CL) comprises continuous reinforcing fibers and a poly(arylene sulfide) polymer.

[0069] The poly(arylene sulfide) polymer is as defined above. It may be the same or a different poly(arylene sulfide) polymer relative to the poly(arylene sulfide) polymer used in the layer (BL). In a preferred embodiment, the poly(arylene sulfide) polymer in the layer (CL) is PPS.

[0070] The PPS suitable for the layer (CL) advantageously has a melt flow rate (at 5 kg and 315.6 °C) of from 10 to 200 g / 10 min, for example from 30 to 150 g / 10 min.

[0071] In an advantageous embodiment, the poly(arylene sulfide) polymer is the only polymer in the layer (CL).

[0072] The layer (CL) comprises continuous reinforcing fibers impregnated with a poly(arylene sulfide) polymer as detailed below. As used herein, the expression "continuous reinforcing fibers" means fibers having a length of at least 5 mm. The length of the fiber corresponds to the longest dimension of the fiber.

[0073] In some embodiments, the continuous reinforcing fibers have a length of at least 1 cm, at least 25 cm or at least 50 cm in the longest dimension. The length of the continuous reinforcing fibers depends on the shape and size of the finished part.

[0074] The continuous reinforcing fibers are selected from the group consisting of: glass fibers, carbon fibers, aluminum fibers, metal fibers, ceramic fibers, titanium fibers, magnesium fibers, boron carbide fibers, rock wool fibers, steel fibers, aramid fibers and natural fibers (such as cotton, linen and wood). Preferably, the continuous reinforcing fibers are selected from the group consisting of: glass fibers, carbon fibers, aramid fibers and ceramic fibers. Advantageously, the continuous reinforcing fibers are carbon fibers.

[0075] In some embodiments, the layer (CL) may include one or more additional continuous reinforcing fibers, each different in composition and as described above.

[0076] Generally, the continuous reinforcing fibers account for at least 5.0% of the total volume of the layer (CL). Typically, the continuous reinforcing fibers account for at least 10.0%, even at least 15.0%, even at least 20.0%, at least 25.0%, even at least 30.0% of the total volume of the layer (CL). The continuous reinforcing fibers are no more than 80.0%, no more than 75.0%, even no more than 70.0% of the total volume of the layer (CL). The continuous reinforcing fibers can conveniently account for 20.0% to 75.0%, 25.0% to 70.0%, 25.0% to 65.0% and even 30.0% to 60.0% of the total volume of the layer (CL). The polymer matrix represents the remaining part of the volume of the layer (CL).

[0077] The continuous reinforcing fibers in the layer (CL) are typically arranged along a single direction. The fibers are typically arranged such that at least 70%, at least 80%, at least 90% or at least 95% of the fibers have a direction within 30 degrees, within 25 degrees, within 20 degrees, within 15 degrees, or within 10 degrees of the direction of other fibers.

[0078] In certain embodiments, the continuous reinforcing fibers in the layer (CL) can be arranged at an angle to each other. The continuous reinforcing fibers can be arranged as a woven fabric or a laminated fabric or any combination of one or more thereof.

[0079] The layer (CL) can be manufactured by methods well known in the art. Generally, the manufacturing method includes the steps of impregnating continuous reinforcing fibers with a poly(arylene sulfide) polymer composition, and then cooling or drying to form the layer (CL).

[0080] Impregnating the continuous reinforcing fibers with a poly(arylene sulfide) polymer composition can be carried out, for example, by a melt impregnation process, which includes bringing the continuous reinforcing fibers into contact with a melt of the polymer material. After melt impregnation, the impregnated continuous reinforcing fibers are cooled to form a solid composite material.

[0081] The impregnation can be carried out by a solution process or a slurry process. In the solution process, a solution is formed by dissolving the polymer in a liquid medium. The solution is coated on the surface of the fibers, for example, by passing the continuous reinforcing fibers through a solution bath. Subsequently, the coated fibers are then heated and consolidated. In the slurry process, the continuous fibers are impregnated with polymer particles, for example, by passing the fibers through a particulate suspension or a fluidized bed of particles. Subsequently, the fibers containing the polymer particles are heated and consolidated.

[0082] The layer (CL) has a thickness generally between 100 microns and 500 microns. This thickness is adapted to provide a multi-layer structure that can be easily shaped to provide an article such as a container.

[0083] Multilayer structure

[0084] The multilayer structure of the present invention comprises at least one layer (BL) and at least one layer (CL) in contact with at least one barrier layer as defined above. There may be more than one layer (BL) in the multilayer structure. There may be more than one layer (CL) in the multilayer structure.

[0085] The multilayer structure may comprise up to ten layers (BL) and up to ten or even more than ten layers (CL).

[0086] The multilayer structure does not include an adhesive or adhesive layer between the layer (BL) and the layer (CL).

[0087] The multilayer structure may include more layers (BL) than layers (CL), or vice versa. Typically, the multilayer structure does not include alternating layers (BL) and layers (CL).

[0088] The multilayer structure may be composed of one or more layers (BL) and one or more layers (CL).

[0089] Advantageously, the multilayer structure comprises one, two, three, four, five, six, seven, eight, nine or ten layers (BL) and one, two, three, four, five, ten, 50, 100 or even more (such as 200 or 300) layers (CL).

[0090] In one embodiment, the multilayer structure comprises a single layer (BL) and multiple layers (CL). The multilayer structure may be composed of a single layer (BL) and one or more layers (CL), and the layer (BL) represents one of the outer surfaces of the multilayer structure.

[0091] In some embodiments, the multilayer structure may include additional layers in contact with the layer (CL) on the opposite side of the layer (BL). The additional layers may or may not contain reinforcing fibers. The additional layers may or may not contain poly(arylene sulfide) polymers. Preferably, the additional layers are not made of metal strips.

[0092] Article

[0093] Another object of the present invention is an article for storing and / or transporting gases, the article comprising a multilayer structure as defined above. Non-limiting notable examples of articles are hoses, pipes, tubes, joints, tanks, reservoirs or generally containers.

[0094] Among these, the multi-layer structure of the present invention is suitable for use as a hose for compressed gases, particularly hydrogen, due to its excellent flexibility and heat cycle resistance. The hose for compressed hydrogen is used as a hose for filling hydrogen from a hydrogen station into a fuel cell vehicle or the like. Since the hose for compressed hydrogen undergoes repeated temperature changes (thermal cycles) from -40 °C or lower to 90 °C or higher due to the filling and unloading of high-pressure hydrogen, the hose needs to have high heat cycle resistance, pressure cycle resistance, and flexibility.

[0095] The hose for high-pressure hydrogen is a hose having a multi-layer structure for a first purpose, wherein the layer (BL) is in contact with the compressed gas, and the layer (CL) represents the outer side of the hose.

[0096] The multi-layer structure of the present invention is characterized by high heat resistance, good hydrogen barrier properties, very good tolerance to pneumatic cycling and decompression, and non-flammability. These characteristics make the multi-layer structure particularly well-suited for use in a container for storing a gas under pressure.

[0097] The term "vessel" is used herein to refer to a hollow reservoir. The vessels of the present invention are in particular hollow reservoirs for containing a gas, preferably a pressurized or compressed gas.

[0098] Advantageously, the vessels obtained from the multi-layer structure according to the present invention do not show signs of explosive decompression (blistering), either in cyclic tests or in static tests.

[0099] Accordingly, another object of the present invention is a vessel for storing or transporting a gas, the vessel comprising a multi-layer structure as defined above.

[0100] The layer (BL) represents the inner layer of the vessel in contact with the gas to be transported or stored, hereinafter also referred to as the "inner layer" or "liner". The layer (CL) represents the outer layer of the vessel. All definitions and preferences provided for the layer (BL), the layer (CL), and the multi-layer structure apply to the vessel.

[0101] The vessel is preferably a pressure vessel, i.e., a vessel suitable for storing and / or transporting a gas under pressure.

[0102] The vessel or preferably the pressure vessel comprises a hollow body and at least one boss. The boss is known to those skilled in the art and it refers to an opening in which a closure is attached, which opening allows a gas or fluid to flow into and out of the vessel. The boss is typically made of metal.

[0103] The hollow body can have any shape suitable for storing a gas, particularly a gas under pressure.

[0104] In some conventional embodiments, the container has a cylindrical shape and the bosses are placed at the ends. Frequently, the container has two bosses at each end of the cylindrical shape. The shape of the hollow body is determined by the intended use and is generally but not exclusively cylindrical. The hollow body can have a diameter between 10.0 cm and 1.0 m. The diameter can be at least 15.0 cm.

[0105] The length of the hollow body also depends on the end use. The hollow body can have a length between 50.0 cm and 10.0 m. These larger lengths are typically used for gas transportation. As an example, for a container in a truck, the length is typically between 1.0 m and 3.0 m.

[0106] The container of the present invention can have an internal volume between 3.5 dm 3 and 5.0 m 3 , and even between 5.0 dm 3 and 1.0 m 3 . The internal volume of the container can be at least 10.0 dm 3 , and even at least 15.0 dm 3 . The internal volume can be up to 1.0 m 3 , and even up to 0.5 m 3 .

[0107] The container includes a hollow body that includes, from the inside to the outside of the container: at least one barrier layer or lining, which is the layer (BL) as defined above, and at least one composite layer in contact with the at least one barrier layer, which is the layer (CL) as defined above. The layer (BL) is in contact with the gas contained in the container.

[0108] The lining is intended to provide a barrier between the fluid or gas and the layer (CL) to prevent leakage. Typically, the layer (CL) is provided around the lining to provide mechanical properties such as burst pressure resistance.

[0109] The container can be manufactured according to any method known in the art.

[0110] For example, the lining can be prepared by blow molding, tube extrusion, injection molding and welding and / or rotational molding. Then the layer (CL) can be applied to the outer surface of the lining by winding a tape containing continuous reinforcing fibers and a poly(arylene sulfide) polymer around the hollow body made of the lining.

[0111] Other manufacturing methods known in the art for manufacturing pressure vessels can be used.

[0112] Therefore, the present invention also relates to a method for preparing a container, the method comprising the following steps:

[0113] a. Provide a liner in the form of a hollow body;

[0114] b. Provide a tape comprising continuous reinforcing fibers and a poly(arylene sulfide) polymer;

[0115] c. Wind the tape around the liner while consolidating the tape by means of heat;

[0116] d. Cool the object obtained at the end of step c. to become rigid.

[0117] The term tape is understood herein to mean an elongated object having a longitudinal direction, a width, a thickness, and a cross-sectional aspect ratio, i.e., the ratio of the thickness to the width. The cross-section is defined as being substantially perpendicular to the longitudinal direction of the tape. The longitudinal direction or machine direction of the tape substantially corresponds to the orientation of the endless fibers. The length dimension of the tape is not particularly limited. The length can exceed 10 km and mainly depends on the continuous fibers and the method used to produce the tape. However, for convenience, the tape can be made in smaller sizes according to the requirements of the intended application.

[0118] The tape typically has a thickness between 100 microns and 500 microns because thicker tapes are more difficult to wind. Thinner tapes have the disadvantage that more winding is required to obtain a hollow body.

[0119] The support can be a liner. The support thus becomes part of the hollow body.

[0120] The winding can be carried out in the form of a tape that comprises continuous reinforcing fibers and a poly(arylene sulfide) polymer.

[0121] The consolidation is preferably carried out by means of heat, such as the heat provided by a laser (e.g., an infrared laser), or a hot gas torch, or a heating element such as an oven. Post-annealing may be carried out.

[0122] The containers according to the invention exhibit a nominal pressure of at least 2.5 MPa, typically at least 20.0 MPa, and even at least 30.0 MPa. The nominal pressure can be up to 70.0 MPa, 100 MPa, or even 150.00 MPa and greater. Advantageously, the containers of the invention have a nominal pressure of 20.0 to 70.0 MPa.

[0123] For storing hydrogen gas in a container according to the invention, a burst pressure of at least 157.5 MPa can be achieved. Containers for storing compressed hydrogen typically require a nominal pressure of 35.0 MPa or 70.0 MPa. The burst pressures measured according to ECE R134 are typically up to 78.8 MPa and 157.5 MPa, respectively.

[0124] Another object of the present invention is a compressed gas in a container, the container comprising the multi-layer structure of the first object, wherein the layer (BL) is in contact with the compressed gas. The gas is advantageously selected from the group consisting of: hydrogen, oxygen, nitrogen, argon, helium, methane, propane, compressed natural gas, CO2, and ammonia.

[0125] The gas is typically at a pressure of at least 5.0 MPa, preferably at least 10.0 MPa. Depending on the gas, the pressure can be up to 150.0 MPa.

[0126] Yet another object of the present invention is a vehicle comprising a container or a compressed gas stored in a container.

[0127] The vehicle can be an automobile, a truck, a train, a ship, an urban mobility vehicle, an airplane, a helicopter, or any other vehicle that can be powered by converting the gas into energy by any means.

[0128] The above embodiments are intended to be illustrative rather than restrictive. Additional embodiments are within the inventive concept. Furthermore, although the present invention has been described with reference to specific embodiments, those skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.

[0129] Examples

[0130] Materials

[0131] PPS1 is XE-5500BL, a poly(phenylene sulfide) polymer commercially available from Solvay Specialty Polymers USA, LLC, having a melt flow rate of 10 g / 10 min (5 kg, 315.6 °C)

[0132] PPS2 was synthesized in a 340-liter reactor having 41.3 kg of aqueous sodium hydrosulfide (57.0 wt%, Nouryan), 30.8 kg of aqueous sodium hydroxide (50.6 wt%, Columbus), 12.1 kg of sodium acetate (Jarchem), and 123.1 kg of N-methyl-2-pyrrolidone (Ashland). After the dehydration step, 58.6 kg of 1,4-dichlorobenzene and 0.108 kg of 1,2,4-trichlorobenzene were added under nitrogen pressure, and the sealed reactor was heated to a maximum temperature of 275 °C. After adding 7.7 kg of additional NMP, the mixture was gradually cooled to obtain granular PPS, which was rinsed with NMP, water, and acetic acid solution at 60 °C - 75 °C, resulting in 35.3 kg of white granular PPS resin. The resin has a melt flow rate of 11 g / 10 min (5 kg, 315.6 °C).

[0133] PPS3 is QA 200P, a poly(phenylene sulfide) polymer commercially available from Solvay Specialty Polymers USA, LLC.

[0134] PA12 is commercially available from EMS Chemie L25 NZ

[0135] 57: a carbon fiber / epoxy UD prepreg commercially available from Solvay SA

[0136] Melt flow rate

[0137] The melt flow rate of the poly(aryl sulfide) polymer was measured according to Procedure B of ASTM D1238 in an extruded plastomer at 315.6 °C using a 5 kg weight and a 0.21 cm × 0.80 cm die after a 5-minute equilibration time.

[0138] Tensile test

[0139] The tensile properties were measured according to ISO 527-2 using specimens meeting the requirements of ISO 1BA at a test speed of 5 mm / min.

[0140] H2 permeability coefficient determination

[0141] Samples for hydrogen permeability testing were prepared as follows. The PPS polymer was dried overnight at 107 °C in a desiccant drying oven with a dew point of -40 °C to ensure that the material was dry before injection molding into plates.

[0142] The PA 12 polymer samples were dried at 70 °C.

[0143] Following the injection molding processing guidelines recommended by the polymer supplier, the materials were injection molded into 10 cm × 10 cm × 0.32 cm plates using a 250-ton Sumitomo SE 250EV-A HD all-electric injection molding machine. The molding machine was equipped with a 45 mm screw size, where the maximum screw speed was 250 rpm and the maximum injection capacity was 0.34 dm3. The machine had a maximum injection size of 21 cm and a maximum injection pressure of 215 MPa. The plates were annealed at a temperature 20 °C above their glass transition temperature for a period of 2 h to ensure complete crystallization before the hydrogen permeability testing.

[0144] The molding conditions are summarized in the following table:

[0145]

[0146]

[0147] The sheets of PPS1, PPS2 and PPS3 were annealed at 110 °C for 2 h. The sheet of PA 12 was annealed at 70 °C for 2 h.

[0148] The samples thus obtained were placed in a sealed chamber and checked for airtightness by applying hydrogen at 1 MPa on the feed side. Subsequently, the chamber was adjusted to the test temperature. On the feed side, H2 was fed at 1 MPa. On the permeate side, synthetic air was fed at a controlled flux and H2 was measured using a calibrated Inficon Sentrac H2 leak detector until a stable value of H2 was obtained to determine the steady state.

[0149] The permeation coefficient was calculated taking into account the sample thickness, the exposed surface, the H2 concentration, the carrier gas flow rate, and the pressure.

[0150] The results of the mechanical properties and the hydrogen permeation coefficient are shown in Table 1.

[0151] Table 1

[0152]

[0153] The data in Table 1 show that PPS1 and PPS2 have significantly lower permeation coefficients compared to aliphatic polyamides such as PA12, which results in higher barrier properties.

[0154] The difference in the permeation coefficient becomes more and more evident at increasing temperatures. For the sheets made of PPS1 and PPS2, the lower dependence of the permeation coefficient on temperature is highly advantageous since containers for gases under pressure are exposed to high temperatures.

[0155] At the same time, PPS1 and PPS2 have higher moduli compared to PA12.

[0156] The combination of the above properties allows the design of thinner linings without compromising the barrier or mechanical properties of the container.

[0157] Static and dynamic blister tests on the multilayer structure

[0158] Preparation of the multilayer structures of Examples 1 and 2

[0159] From the use of Solvay Specialty Polymers USA, LLC in Starting with the unidirectional PPS carbon fiber tape made of commercially available PPS polymer sold under the trade name QA 200N and approximately 55% volume fraction of carbon fiber, a composite sample with a thickness of 4 mm was prepared in a press at 320 °C, 2.5 MPa, and a holding time of 20 min.

[0160] Samples of the PPS sheets PPS1 (Example 2) and PPS3 (Example 1) prepared above, as well as the PPS / CF composite samples, were co-consolidated in a press under limited contact time under the following operating conditions (to simulate the conditions of the winding process): preheating of the mold at 300 °C; a contact time of 3', and a contact pressure of 0.7 MPa.

[0161] Preparation of the multilayer structure of Comparative Example 1

[0162] The sheet of PA12 was co-cured with 57 carbon fiber / epoxy prepregs to prepare a multi-layer structure including a PA 12 lining and a carbon fiber / epoxy reinforcement layer: Four layers of 150 mm × 150 mm 57 were used as the reinforcing epoxy substrate with a 0 / 90 orientation.

[0163] A 125 mm × 125 mm square polymer substrate PA 12 was applied on the epoxy substrate. No special preparation was carried out for the epoxy prepreg or the polymer substrate.

[0164] All laminate stacks were cured using standard vacuum bag consumables. Curing was carried out in an oven under vacuum (below 50 mbar). The temperature was controlled using a Eurotherm controller in a ramp, hold, and cool manner. The curing temperature was 120 °C and the curing time was one hour.

[0165] Conditions for testing

[0166] The samples of Example 1 and 2 and Comparative Example 1 were subjected to a dynamic cycling test to detect blistering between the lining and the fiber reinforcement layer. The samples were introduced into the test device and subjected to the following repeated pressurization and depressurization cycles:

[0167] ○ Adjusted to 50 ± 2 °C

[0168] ○ 250 cycles were carried out

[0169] ■ Pressurized to >= 44 MPa

[0170] ■ Held at >= 44 MPa for 24.8 min

[0171] ■ Depressurized to <= 0.5 MPa at approximately 1,000 MPa / h

[0172] ■ Maintain at <= 0.5 MPa for 24.8 min

[0173] ○ Depressurize to ambient pressure

[0174] ○ Remove the sample from the pressure vessel

[0175] ● Measure the weight after 60 minutes and 24 hours

[0176] Report the weight difference before / after the test and report foaming

[0177] At the end of the test, analyze the sample by RX chromatography using a 150 kV source and a 20 μ focus. Bubbles were noticed at the liner (BL) / composite (CL) interface

[0178] Conduct a static foaming test under the following conditions

[0179] ○ Adjust to 50 ± 2 °C

[0180] ○ Pressurize to 87.5 MPa

[0181] ○ Immerse for 48 h (exposure)

[0182] ○ Depressurize to ambient pressure as quickly as possible (target: < 1 s)

[0183] Report the weight difference before / after the test and report foaming

[0184] The results are shown in Table 2

[0185] Table 2

[0186]

[0187]

[0188] The results show that the quality of the multi-layer structure of the present invention in Examples 1 and 2 is very stable. The weight loss of the comparative multi-layer structure containing a PA12 liner and a thermosetting carbon fiber composite layer was measured. The multi-layer structure of the present invention maintained a very good interface without showing bubbles, and there was no foaming at the interface between the liner and the fiber-reinforced structural layer in both dynamic and static foaming tests. Several bubbles and cracks were observed in the multi-layer structure of Comparative Example 1

Claims

1. A multilayer structure comprising at least one gas barrier layer [layer (BL)] and at least one composite material layer [layer (CL)] in contact with the at least one gas barrier layer, wherein: - Layer (BL) comprises a poly(arylene sulfide) polymer; and - Layer (CL) comprises continuous reinforcing fibers and a poly(arylene sulfide) polymer.

2. The multi-layer structure according to claim 1, wherein, The poly(arylene sulfide) polymer contains at least 50 mol% of repeating units (R PAS ), and the repeating units are represented by a formula selected from the group consisting of the following formulas: and Wherein: -R is independently selected in each case from the group consisting of: C1-C 12 alkyl, C7-C 24 alkylaryl, C7-C 24 aralkyl, C6-C 24 arylene and C6-C 18 aryloxy; - T is selected from the group consisting of a bond, -CO-, -SO2-, -O-, -C(CH3)2, phenyl, and -CH2-; - i is independently in each case an integer of 0 or from 1 to 4; and - j is independently in each case an integer of 0 or from 1 to 3.

3. The multi-layer structure according to claim 2, wherein, The repeating unit (R PAS ) is represented by formula (4): Wherein R and i are as defined in claim 2, preferably in formula (4), i is 0 in all cases.

4. The multi-layer structure according to any one of claims 1 to 3, wherein, Layer (BL) comprises the poly(arylene sulfide) polymer and at least one impact modifier in an amount of 1.0 wt% to 25.0 wt% based on the total weight of layer (BL).

5. The multilayer structure according to any one of the preceding claims, wherein, These continuous reinforcing fibers have a length of at least 5 mm.

6. The multilayer structure according to any one of the preceding claims, wherein, These continuous reinforcing fibers are selected from the group consisting of glass fibers, carbon fibers, aramid fibers, and ceramic fibers.

7. The multi-layer structure according to any one of the preceding claims, wherein, These continuous reinforcing fibers in layer (CL) are present in an amount of 15.0% to 80.0% by volume based on the total volume of layer (CL).

8. A multilayer structure according to any one of the preceding claims, the multilayer structure consisting of one or more layers (BL) and one or more layers (CL), preferably the multilayer structure consisting of one layer (BL) and one or more layers (CL).

9. An article for storing and / or transporting a gas, the article comprising a multilayer structure according to any one of the preceding claims.

10. An article according to claim 9, the article being in the form of a container or a hose.

11. The container or hose according to claim 10, wherein, Layer (BL) represents the inner layer of the container or hose and layer (CL) represents the outer layer of the container or hose.

12. A container according to any one of claims 10 or 11, the container being in the shape of a hollow body having one or more of the following: - A diameter of 10.0 cm to 1.0 m; - A length of 50.0 cm to 10.0 m; and -3.5 dm 3 to 5.0 m 3 of the internal volume 13. A compressed gas, which is accommodated in a container as described in any one of claims 10 to 12, wherein, The compressed gas is in contact with layer (BL).

14. A compressed gas according to claim 13, the compressed gas being selected from the group consisting of hydrogen, oxygen, nitrogen, argon, helium, methane, propane, compressed natural gas, CO2, ammonia.

15. A compressed gas according to claim 13 or 14, the compressed gas being at a pressure of 1.0 MPa to 150.0 MPa.

16. A vehicle comprising a container according to any one of claims 10 to 12 or a compressed gas according to any one of claims 13 to 15.

17. Use of a container according to any one of claims 10 to 12 for storing or transporting a compressed gas.

18. Use of a hose according to claim 10 or 11 for transporting a gas, preferably a compressed gas.

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