A multi-layered structure for transporting or storing gas, or for utilizing it from the seabed or offshore oil deposits.

Abstract

The present invention relates to a multilayer structure for transporting or storing gas or utilizing it in oil or gas deposits on the seabed, comprising at least one sealing layer and at least one composite reinforcing layer from inside to outside, wherein the innermost composite reinforcing layer is welded to the outermost adjacent sealing layer, and the sealing layer is composed of a composition mainly comprising at least one semicrystalline thermoplastic polymer P1i (i = 1 to n, where n is the number of sealing layers) having a Tf of less than 280°C, particularly less than 265°C, as measured according to ISO 11357-3: 2013, wherein at least one thermoplastic polymer of each sealing layer may be the same or different, and at least one of the composite reinforcing layers is composed of a fibrous material in the form of continuous fibers impregnated with a composition mainly comprising at least one thermoplastic polymer P2j (j = 1 to m, where m is the number of reinforcing layers) which is particularly semicrystalline, and wherein the thermoplastic polymer P2j is ISO 11357-3: The invention relates to a multilayer structure having a Tg ≥ Tu + 20°C (where Tu is greater than 50°C, particularly greater than 100°C) which, when measured according to 2013, the maximum operating temperature (Tu) of the structure is exceeded, and hydrogen is excluded from the gas transport or gas storage, and the multilayer structure selected from the storage, pipe or tube for transporting or storing hydrogen is excluded.

Description

Technology Field

[0001] This patent application relates to a composite multilayer structure for transporting or storing gas or utilizing it from an underwater oil or gas deposit, and a method for manufacturing said structure. Background Technology

[0002] The development of offshore oil deposits utilizes pipes that transport materials used in extreme conditions, and in particular, connect various underwater devices on the platform and transport extracted hydrocarbons, which are typically transported at high temperatures and high pressures (e.g., 700 bar).

[0003] During the operation of the equipment, there are serious problems with the mechanical strength and thermal and chemical resistance of the materials used. These pipes, in particular, must withstand high temperatures of oil, gas, water, and a mixture of at least two of the above products for a period of up to 20 years.

[0004] Typically, such pipes comprise an unsealed inner layer of metal formed by a spirally wound, profiled metal strip, for example, a lock-sealed strip. This metal inner layer provides the pipe with its shape and is generally coated by extrusion together with a polymer layer intended to provide sealing.

[0005] These outer shells are mainly, Optionally, it must be able to be continuously extruded onto a support of an internal carcass, and It must be sufficiently flexible to accommodate the curvature applied to the flexible pipe during manufacturing, laying, and use (movement due to expansion or lifting of the flexible pipe to change the use site), and It must withstand creep caused by compressive forces that are exacerbated by temperature levels. It must be chemically stable enough so that creep does not occur in the gaps (spaces or play) between the metal reinforcements (e.g., Z-shaped self-locking seams or T-shaped seams) supported by the sheath when the pipeline is pressurized by transported effluent, and so that its mechanical properties and sealing do not deteriorate to an unacceptable degree during the life of the flexible pipe.

[0006] For transporting or storing gas or utilizing it in oil and gas deposits, it is advantageous to use a composite pipe comprising such a sealing coating, also referred to as a liner (which provides sealing, chemical resistance, and abrasion resistance of the pipe), reinforced by an outer adhesive layer made of a composite material, manufactured by winding filaments from a unidirectional (UD) tape deposited as a continuous layer on the liner at one or more orientation angles with respect to the axis of the pipe to provide sufficient flexibility to the composite pipe. The composite reinforcement enables the pipe to withstand pressure (internal pressure of the fluid and external pressure when used in a body of deep water).

[0007] This technology was developed by the company Airborne, for example, in document FR 2964173.

[0008] More recently, Technip (WO2012118379) has expressed interest in this pipe concept with metal external reinforcement to remove the inner carcass of the current coastal flexible pipe and optionally, remove the metal reinforcement forming the pressure arch.

[0009] However, the solution considered for this type of composite pipe is based on using the same polymer for the matrix of the liner and the composite to ensure excellent and durable adhesion between the liner and the composite.

[0010] For example, Airborne has developed various flexible pipes having a sealing sheath bonded to a composite reinforcement without an internal carcass, including a PA11 liner with a PA11 FC composite (JIP completed in 2011), a PA12 liner with a PA12 FC composite, or even a PVDF liner with a PVDF FC composite. However, all of these structures have the disadvantage that the matrix of the composite reinforcement has a glass transition temperature (Tg) lower than the pipe's operating temperature, Tu, i.e., 60 to 80°C for pipes based on PA11 or PA12, 50°C in a dry state relative to the pipe's operating temperature, Tu, and -40°C for PVDF, above 100°C and often close to 130°C during continuous operation. In the case of PVDF, the stiffness (modulus) of the matrix is ​​maintained above its Tg until it reaches another transition, the alpha transition at approximately 100°C, and at temperatures above that, its behavior becomes purely rubbery. Accordingly, in all of the above industrial and commercial cases of TP matrix composite pipes, the matrix of the composite reinforcement is in a completely rubberized state at the composite pipe service temperature Tu.

[0011] To address these issues and prevent the material from becoming rubbery at a service temperature of 130°C in such cases, Kutting & Total, later Vitrex and Magma, developed a solution involving a composite reinforcement in which the matrix has a Tg higher than the maximum service temperature. This solution includes a PEEK sealing sheath (or liner) reinforced by a composite having a PEEK matrix. The Tg of PEEK is 140°C, and thus, since this Tg is higher than the maximum service temperature, it meets the requirements for high strength. The disadvantage is that, consequently, the sealing sheath (liner) is also very rigid, which can limit its fatigue resistance and is a major drawback in the production of flexible pipes. Furthermore, the processing temperature of this type of sealing sleeve is very high (typically 380 to 400°C), and in the case of a general deformation process such as tube extrusion, this poses significant difficulties in terms of tooling and process control.

[0012] In addition, in collaboration with Airborne, Ticona (Celanese) provides composite pipes containing PPS FC reinforcement and PPS sealing sheaths.

[0013] When Tu > 90°C, this structure presents the same problem for the composite matrix as PVDF-based solutions (i.e., Tg < Tu), but additionally, presents the problem of deformation temperature (typically 350°C versus 250°C for PPS and PVDF, respectively).

[0014] When Tu < 90℃, PPS is suitable for the matrix of the composite, but there are problems with the extrusion temperature of the sealing sheath (liner), such as the problem of its high strength which limits the flexibility of the composite pipe, and the problem of its low fatigue resistance due to Tg being higher than Tu.

[0015] Accordingly, on the one hand, there is a method of optimizing the matrix of the composite to optimize its mechanical strength at high temperatures, and on the other hand, optimizing the material constituting the sealing liner to optimize its application temperature without reducing the adhesion of the composite reinforcement to the sealing liner. Accordingly, selective changes to the composition of the material containing the sealing sheath, which are performed to ensure at least partial miscibility with the composite matrix, should not result in a significant increase in the extrusion temperature of such liners compared to those currently performed with polyamide and PVDF (i.e., < 300°C, preferably < 290°C, much more preferentially < 250°C).

[0016] This problem is solved by providing a multilayer structure of the present invention, particularly a flexible pipe, which is a completely bonded "2-material" composite pipe and, in particular, a high-strength composite reinforcement deposited by filament winding on a liner pre-extruded at a relatively low temperature. The adhesion between the composite and the liner is very good.

[0017] Accordingly, the present invention relates to a multilayer structure selected from a storage tank, pipe, or tube for transporting or storing gas or utilizing it in a subsea oil or gas deposit, comprising at least one sealing layer and at least one composite reinforcing layer from the inside to the outside. The innermost composite reinforcing layer is welded to the outermost adjacent sealing layer, and The sealing layer is composed of a composition mainly comprising at least one semicrystalline thermoplastic polymer P1i (i=1 to n, where n is the number of sealing layers), and its Tm is less than 280°C, particularly less than 265°C, when measured according to ISO 11357-3: 2013. At least one thermoplastic polymer of each of the above sealing layers may be the same or different, and At least one of the above composite reinforcing layers is particularly composed of a fibrous material in the form of continuous fibers impregnated with a composition mainly comprising at least one semicrystalline thermoplastic polymer P2j (j=1 to m, where m is the number of reinforcing layers), wherein the thermoplastic polymer P2j has a Tg exceeding the maximum operating temperature (Tu) of the structure when measured according to ISO 11357-3:2013, Tg ≥ Tu + 20°C (Tu is greater than 50°C, particularly greater than 100°C), and The invention relates to a multilayer structure in which hydrogen is excluded from the above gas transport or gas storage, and a multilayer structure intended to transport selected hydrogen from a storage, pipe or tube is excluded.

[0018] Accordingly, the inventors unexpectedly used different polymers for the composite matrix and liner, and specifically, The matrix of the composite reinforcement is retained in its glassy domains and, in order to have high stiffness and thus enable the composite to have high mechanical strength, is composed of a polymer having a Tg significantly higher than the maximum operating temperature Tu of the reservoir or pipe (typically, Tg > Tu + 20°C), and It has been discovered that the semicrystalline polymer constituting the liner has a low melting point Tm and can be processed by extrusion, extrusion blow molding, rotational molding, injection, or, in some cases, by winding a pure resin film at an intermediate temperature that is typical to those skilled in the art with respect to the Tm of such polymer, less than 280°C, preferably less than 265°C. Semicrystalline polymers with a low Tm known to date also have a low Tg, which, in most cases, will be below the maximum operating temperature. Consequently, the polymer constituting the liner will act within its rubberized domains, and thus will be very flexible and, consequently, very resistant to fatigue. Its semicrystalline nature ensures excellent resistance to chemical penetration, wear, and creep, and the two aforementioned polymers (one comprising the matrix of the composite and the other comprising the liner) are sufficiently miscible to ensure the weldability of the composite to the liner, and consequently, ensure excellent adhesion between the liner and the composite. The durability of the adhesion will be ensured by the durability of the materials constituting the mixture at the interface of the two materials, that is, at the welded joint. The miscibility of the two polymers is preferably expressed as a single Tg, or is not expressed by the presence of two Tg values ​​intermediate to the Tg of the two pure polymers, for example, by the characteristic features of some homogeneous mixture.

[0019] The immiscibility of the two polymers causes the presence of two Tg in the mixture of the two polymers, corresponding to the individual Tg of the pure polymers taken individually.

[0020] "Multilayer structure" means, for example, a reservoir, pipe, or tube that includes or consists of multiple layers, particularly two layers.

[0021] The term "gas" refers to any gas, and in particular, seabed-extracted gas, and in particular, natural gas excluding hydrogen.

[0022] The sealing layer or layers are the innermost layers compared to the composite reinforcing layer, which is the outermost layer.

[0023] The sealing layer comes into contact with oil and gas extracted from the gas or seabed even when an inner and, accordingly, innermost non-sealing metallic layer is present, formed by a spirally wound, profiled metallic strip such as a lock-seamed strip to form the carcass, and sealing layer(s) are coated thereon by extrusion.

[0024] When several sealing layers exist, only the innermost layer of the sealing layer comes into direct contact with the gas or oil and gas extracted from the seabed.

[0025] When only a sealing layer and a composite reinforcing layer exist, and thus a two-layer multilayer structure is formed, such two layers are welded and thus bonded to each other in direct contact.

[0026] When there are several sealing layers and / or several composite reinforcing layers, the outermost layer of the sealing layer, and accordingly, the layer facing the layer in contact with the gas or oil and gas extracted from the seabed, is welded to the innermost layer of the composite reinforcing layer and, accordingly, bonded to each other so as to come into direct contact with each other.

[0027] Other composite reinforcing layers are also welded together.

[0028] Another sealing layer is also welded together. In relation to sealing layer(s) and thermoplastic polymer P1i

[0029] One or more sealing layers may exist.

[0030] Each of the above layers is composed of a composition mainly comprising at least one thermoplastic polymer P1i, where i corresponds to the number of layers present. i is 1 to 10, specifically 1 to 5, particularly 1 to 3, and preferentially i = 1.

[0031] The term "predominantly" means that at least one polymer is present in an amount of more than 50 weight percent of the total weight of the composition.

[0032] Advantageously, the at least one major polymer is present in an amount of more than 60 weight%, specifically more than 70 weight%, particularly more than 80 weight%, more specifically more than 90 weight% with respect to the total weight of the composition.

[0033] The above composition may further include shock modifiers and / or additives.

[0034] Additives can be selected from antioxidants, heat stabilizers, UV absorbers, light stabilizers, lubricants, inorganic fillers, flame retardants, nucleating agents, plasticizers, dyes, carbon black, and carbonaceous nanofillers.

[0035] Advantageously, the composition mainly consists of the thermoplastic polymer P1i, 0 to 5 weight percent of an impact modifier, and 0 to 5 weight percent of an additive, and the sum of the components of the composition is 100% (based on a maximum of 90% P2i).

[0036] In each layer, the at least one major polymer may be the same or different.

[0037] In one embodiment, a single major polymer is present in the sealing layer welded to the composite reinforcing layer at least. Thermoplastic polymer P1i

[0038] Thermoplastic resins, or thermoplastic polymers, generally refer to semicrystalline materials that are solid at ambient temperatures, soften during an increase in temperature, particularly after passing through their glass transition temperature (Tg), exhibit a rapid transition when passing through a temperature referred to as their melting point (Tm), and become solid again when the temperature decreases below their crystallization temperature.

[0039] Tg, Tc, and Tm are determined by differential scanning calorimetry (DSC) according to standards 11357-2:2013 and 11357-3:2013, respectively.

[0040] The number average molecular weight Mn of the thermoplastic polymer is preferably in the range of 10,000 to 40,000, preferably 12,000 to 30,000. Such Mn values ​​may correspond to an intrinsic viscosity of 0.8 or higher when measured in m-cresol according to standard ISO 307:2007, except for changing the solvent (using m-cresol instead of sulfuric acid and the temperature is 20°C).

[0041] Examples of suitable semicrystalline thermoplastic polymers in the present invention include polyamides, such as copolymers, for example, polyamide-polyether copolymers, polyesters, PVDF, and PVDF / PEI blends (wherein PVDF is dominant).

[0042] More specifically, among semicrystalline polymers, polyamides and their semicrystalline copolymers are preferred.

[0043] The nomenclature used to define polyamides is described in ISO standard 1874-1:2011 "Plastics -- Materials Polyamides (PA) pour moulage et extrusion - Partie 1: Designation", in particular, on page 3 (Tables 1 and 2), and is widely known to those skilled in the art.

[0044] Polyamides may be homopolyamides or copolyamides or mixtures thereof.

[0045] Advantageously, the thermoplastic polymer is a long-chain aliphatic polyamide, that is, a polyamide having an average number of carbon atoms per nitrogen atom greater than 8.5, preferably greater than 9.

[0046] In particular, the long-chain aliphatic polyamide is selected from polyamide 11 (PA11), polyamide 12 (PA12), polyamide 1010 (PA1010), polyamide 1012 (PA1012), polyamide 1212 (PA1012), or a mixture thereof or a copolyamide thereof, in particular, PA11 and PA12.

[0047] Advantageously, the thermoplastic polymer is a long-chain semi-aromatic polyamide, that is, a polyamide having an average number of carbon atoms per nitrogen atom greater than 8.5, preferably greater than 9, and a melting point of 240°C to 280°C.

[0048] In particular, the long-chain semi-aromatic polyamide is selected from polyamide 11 / 5T, 11 / 6T, or 11 / 10T. Obviously, in these cases, the content of 11 must be carefully selected so that the Tm of the polymer is less than 280°C, preferably less than 265°C.

[0049] Advantageously, each sealing layer is composed of a composition containing the same type of polymer, in particular, polyamide.

[0050] Advantageously, the composition containing the polymer P1i has a black color and can absorb radiation suitable for welding.

[0051] Various methods exist for welding thermoplastic polymer parts. Accordingly, contact or non-contact heating blades, ultrasonics, infrared rays, vibration, and rotation may be used for one element being welded, for other or even laser welding.

[0052] In particular, the welding of thermoplastic polymer elements by laser welding requires that the two elements to be welded have different properties with respect to radiation, specifically laser radiation. One of the elements must be transparent to radiation, specifically laser radiation, while the other must absorb radiation, specifically laser radiation. Radiation, specifically laser radiation, passes through the transparent part and subsequently reaches the absorbing element, where it is converted into heat. This melts the contact area between the two elements, thereby enabling welding to take place.

[0053] In some applications, it is desired that both parts to be welded, including a portion that is transparent to laser radiation, be black.

[0054] To make these materials absorbent, it is known that various additives, including carbon black, are added to the polymer to provide a black color and enable it to absorb radiation suitable for welding.

[0055] In one embodiment, welding is performed by a system selected from a laser, IR heating, or induction heating.

[0056] When welding is performed by laser welding, composition P1i includes a non-aggregated or non-aggregated carbonaceous filler.

[0057] When welding is performed by induction, composition P1i contains metallic particles.

[0058] Advantageously, welding is performed by a laser system. In relation to composite reinforcing layers and thermoplastic polymer P2j

[0059] One or more composite reinforcement layers may exist.

[0060] Each of the above layers is composed of a composition mainly comprising at least one thermoplastic polymer P2j (where j corresponds to the number of layers present).

[0061] j includes 1 to 10, particularly 1 to 5, more specifically 1 to 3, and primarily j = 1.

[0062] The term "mainly" means that at least one polymer is present in an amount of more than 50 weight percent of the total weight of the composition.

[0063] Advantageously, the at least one major polymer is present in an amount greater than 60 weight%, specifically greater than 70 weight%, particularly greater than 80 weight%, more specifically greater than 90 weight% with respect to the total weight of the composition.

[0064] The above composition may further include shock modifiers and / or additives.

[0065] Additives may be selected from antioxidants, heat stabilizers, UV absorbers, light stabilizers, lubricants, inorganic fillers, flame retardants, nucleating agents, plasticizers, and dyes.

[0066] Advantageously, the composition is mainly composed of the thermoplastic polymer P2j, 0 to 5 weight percent of an impact modifier, and 0 to 5 weight percent of an additive, and the sum of the components of the composition is 100% (based on a maximum of 90% of P2j).

[0067] In each layer, the at least one major polymer may be the same or different.

[0068] In one embodiment, a single major polymer is present in a composite reinforcing layer welded to a sealing layer at least.

[0069] In one embodiment, each reinforcing layer comprises the same type of polymer, in particular, polyamide. Thermoplastic polymer P2j

[0070] Thermoplastic resin, or thermoplastic polymer, is generally intended to mean a material that is solid at ambient temperature, may be semicrystalline or amorphous, particularly semicrystalline, softens during an increase in temperature, particularly after passing its glass transition temperature (Tg), flows at higher temperatures when amorphous, or exhibits a melting point (Tm) when semicrystalline, and becomes solid again when the temperature decreases below its crystallization temperature (in the case of semicrystalline) and below its glass transition temperature (in the case of amorphous).

[0071] Tg, Tc, and Tm are determined by differential scanning calorimetry (DSC) according to standards 11357-2:2013 and 11357-3:2013, respectively.

[0072] The polymer P2j of at least one composition of the above composite reinforcing layer has a Tg higher than the maximum operating temperature (Tu) of the structure, in particular, Tg ≥ Tu + 20℃.

[0073] In one embodiment, the polymer P2j has Tg ≥ Tu + 20℃ regardless of the position of the reinforcing layer.

[0074] In another embodiment, the reinforcing layer, which is composed of a composition including a polymer P2j having Tg ≥ Tu + 20℃, is a layer welded to the sealing layer.

[0075] In another embodiment, the reinforcing layer, which is composed of a composition including polymer P2j, has Tg ≥ Tu + 20°C and is the outermost reinforcing layer of the structure. The number average molecular weight Mn of the thermoplastic polymer is preferably in the range of 10,000 to 40,000, preferably 12,000 to 30,000. Such Mn values ​​may correspond to an intrinsic viscosity of 0.8 or higher when measured in m-cresol according to standard ISO 307:2007, except for changing the solvent (using m-cresol instead of sulfuric acid and the temperature is 20°C).

[0076] Examples of suitable semicrystalline thermoplastic polymers in the present invention include, in particular, copolymers, e.g., polyamide-polyether copolymers, polyesters, polyaryletherketone (PAEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetherketone etherketone ketone (PEKEKK), polyimides, in particular, polyetherimide (PEI) or polyamide-imide, polysulfones (PSU), in particular, polyarylsulfones, e.g., polyphenylsulfone (PPSU), polyethersulfone (PES), and polyamides having aromatic and / or alicyclic structures.

[0077] Semicrystalline polymers, in particular, polyamides and their semicrystalline copolymers are particularly preferred.

[0078] The nomenclature used to define polyamides is described in detail on page 3 (Tables 1 and 2) of ISO standard 1874-1:2011 "Plastics - Materials of polyamides (PA) for molding and extrusion - Partie 1: Designation", and is widely known to the parties involved.

[0079] Polyamides may be homopolyamides or copolyamides or mixtures thereof.

[0080] Advantageously, the semicrystalline polyamide is a semi-aromatic polyamide, more specifically, a semi-aromatic polyamide of the formula X / YAr described in EP1505099, more specifically, a unit of the formula A / XT (wherein A is selected from a unit obtained from an amino acid, a unit obtained from a lactam, and a unit corresponding to the formulas (Ca diamine) and (Cb diacid), wherein a represents the number of carbon atoms of the diamine, and b represents the number of carbon atoms of the diacid, each of a and b is 4 to 36, advantageously, 9 to 18, and 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 diacid, alicyclic diacid and aromatic diacid.

[0081] A semi-aromatic polyamide having the formula A / 6T, A / 9T, A / 10T, or A / 11T (where A is as defined above), in particular, PA MPMDT / 6T, PA11 / 10T, PA5T / 10T, PA11 / BACT, PA11 / 6T / 10T, PA11 / 6T / 10T, PA11 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 / BACT / 10T, PA11 / MPMDT / 6T, PA11 / MPMDT / 10T, PA11 / BACT / 10T, PA11 / BACT / 10T, It is a polyamide selected from PA11 / MXDT / 10T and 11 / 5T / 10T.

[0082] T corresponds to terephthalic acid, MXD corresponds to m-xylylene diamine, MPMD corresponds to methylpentamethylene diamine, and BAC corresponds to bis(aminomethyl)cyclohexane.

[0083] Advantageously, each composite reinforcing layer is composed of a composition containing the same type of polymer, in particular, polyamide.

[0084] Advantageously, the composition containing the polymer P2j is transparent to radiation suitable for welding.

[0085] Thermoplastic polymers are generally transparent for welding purposes, particularly for laser welding. Carbonaceous nanofillers make it possible to impart a black color to a layer of a composition containing a thermoplastic polymer while maintaining the transparency of the layer to laser radiation.

[0086] Advantageously, carbonaceous nanofillers are non-aggregated or non-aggregated.

[0087] Advantageously, carbonaceous nanofillers are introduced into the composition in an amount of 100 ppm to 500 ppm, and preferably 100 ppm to 250 ppm.

[0088] Advantageously, carbonaceous nanofillers are selected from carbon nanotubes (CNT), carbon nanofibers, graphene, nanoscale carbon black, and mixtures thereof.

[0089] Advantageously, nanometer carbon black is not present in carbonaceous nanofillers.

[0090] In one embodiment, welding is performed by a system selected from a laser, IR heating, or induction heating.

[0091] Advantageously, welding is performed by a laser system.

[0092] Advantageously, the laser radiation is infrared laser radiation, preferably having a wavelength of 700 nm to 1200 nm, and preferably 800 nm to 1100 nm. In relation to structures

[0093] Accordingly, the multilayer structure comprises at least one sealing layer and at least one composite reinforcing layer welded together.

[0094] In one embodiment, in the multilayer structure, each polymer P1i of each sealing layer is partially or completely miscible with each polymer P1i of an adjacent layer(s), each polymer P2j of each reinforcing layer is partially or completely miscible with each polymer P2j of an adjacent layer(s), each polymer P2j is partially or completely miscible with each polymer P1i when they are adjacent, and polymer P21 is partially or completely miscible with the adjacent polymer P11, and the total or partial miscibility of the polymers is defined by the difference in glass transition temperatures of the two resins in the mixture in relation to the difference in glass transition temperatures of the two resins prior to the mixture, the miscibility is total when the difference is zero, the miscibility is partial when the difference is different from zero, and the inmiscibility of polymer P2j and polymer P1i is excluded.

[0095] When the miscibility of the above polymer is partial, the difference is that the greater the miscibility, the smaller the difference.

[0096] Advantageously, when the miscibility of the polymer is partial, the difference is less than 30% in absolute value, preferentially less than 20%.

[0097] In one embodiment, depending on whether the miscibility is complete or partial, the glass transition temperature(s) of the mixture are between the glass transition temperatures of the polymer prior to blending and, preferably, between 5°C and 10°C, and must be different from these glass transition temperatures.

[0098] The expression "fully miscible" means that, for example, when two polymers P11 and P12 having Tg11 and Tg12 respectively are present in two adjacent sealing layers or two adjacent reinforcing layers, the mixture of the two polymers has only one Tg1112 value between Tg11 and Tg12.

[0099] These Tg1112 values ​​are at least 5°C higher than Tg11, in particular, at least 10°C higher, and at least 5°C lower than Tg12, in particular, at least 10°C lower.

[0100] The expression “partially miscible” means that, for example, when two polymers P11 and P12 each having Tg11 and Tg12 are each present in two adjacent sealing layers or two adjacent reinforcing layers, the mixture of the two polymers has two Tg: Tg'11 and Tg'12, where Tg11 < Tg'11 < Tg'12 < Tg12.

[0101] These Tg'11 and Tg'12 values ​​are at least 5°C higher than Tg11, in particular, at least 10°C higher, and at least 5°C lower than Tg12, in particular, at least 10°C lower.

[0102] The immiscibility of the two polymers results in the presence of two Tg, Tg11, and Tg12 in the mixture of the two polymers, corresponding to the individual Tg, Tg11, and Tg12 of the separately obtained pure polymers.

[0103] Advantageously, the welded sealing and reinforcing layers are manufactured from compositions each comprising different polymers.

[0104] Nevertheless, the above different polymers may be of the same type.

[0105] Accordingly, when one of the two welded composite reinforcing layers and the sealing layer is made of a composition comprising an aliphatic polyamide, the other layer is made of a composition comprising a polyamide that is not aliphatic and, for example, a semi-aromatic polyamide to have a high-Tg polymer as a matrix of the composite reinforcing.

[0106] The above multilayer structure may include up to 10 sealing layers and up to 10 composite reinforcing layers.

[0107] It is evident that the above multilayer structure is not necessarily symmetrical, and accordingly, it may include more sealing layers than composite layers, or vice versa.

[0108] Advantageously, the multilayer structure comprises 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 sealing layers, and 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 composite reinforcing layers.

[0109] Advantageously, the multilayer structure comprises 1, 2, 3, 4, or 5 sealing layers, or 1, 2, 3, 4, or 5 composite reinforcing layers.

[0110] Advantageously, the multilayer structure comprises one, two, or three sealing layers and one, two, or three composite reinforcing layers.

[0111] Advantageously, these are composed of compositions each containing different polymers.

[0112] Advantageously, these are composed of a polyamide corresponding to polyamides P1i and P2j, respectively.

[0113] Advantageously, these are composed of compositions each containing different polyamides.

[0114] In one embodiment, the multilayer structure comprises a single sealing layer and several reinforcing layers, wherein the sealing layer is welded to the adjacent reinforcing layer.

[0115] In another embodiment, the multilayer structure comprises a single reinforcing layer and several sealing layers, wherein the reinforcing layer is welded to the adjacent sealing layer.

[0116] In one advantageous embodiment, the multilayer structure comprises a single sealing layer and a single composite reinforcing layer that are welded together.

[0117] Accordingly, all combinations of these two layers fall within the scope of the present invention, provided that at least the innermost composite reinforcing layer is welded to the outermost adjacent sealing layer, and other layers are not welded together or welded.

[0118] Advantageously, in the above multilayer structure, each sealing layer is composed of a composition including a polymer P1i of the same type, in particular, a polyamide.

[0119] The expression "polymer of the same type" means a polyamide that may be the same or different depending on the layer, for example.

[0120] Advantageously, the polymer P1i is a polyamide, and the polymer P2j is a polyamide.

[0121] Advantageously, polyamide P1i is the same for all sealing layers.

[0122] Advantageously, the polymer P1i is a long-chain aliphatic polyamide, in particular, PA1010, PA1012, PA1212, PA11, PA12, in detail, PA11 or PA12.

[0123] Advantageously, polyamide P1i is a long-chain semi-aromatic polyamide, in particular, PA11 / 5T, PA11 / 6T or PA11 / 10T. Clearly, in this case, the content of 11 should be carefully selected so that the Tm of the polymer is less than 280°C, in particular, 265°C.

[0124] Advantageously, in the above multilayer structure, each reinforcing layer is composed of a composition including the same type of polymer P2j, in particular, polyamide.

[0125] Advantageously, polyamide P2j is the same for all reinforcing layers.

[0126] Advantageously, the polymer P2j is a semi-aromatic polyamide selected particularly from PA MXDT / 6T, PA11 / 10T, PA11 / BACT, PA 5T / 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, PA 5T / 10T.

[0127] Advantageously, in the above multilayer structure, each sealing layer is composed of a composition comprising the same type of polymer P1i, particularly polyamide, and each reinforcing layer is composed of a composition comprising the same type of polymer P2j, particularly polyamide, provided that polyamides P1i and P2j are different; that is, where the sealing layer(s) are composed of a composition comprising long-chain aliphatic polyamide, the sealing layer(s) are composed of a composition comprising semi-aromatic polyamide.

[0128] Advantageously, the polymer P1i is a long-chain aliphatic polyamide, in particular, PA1010, PA1012, PA1212, PA11, PA12, in particular, PA11 or PA12, and the polymer P2j is a semi-aromatic polyamide, in particular, selected from PA MPMDT / 6T, PA PA11 / 10T, PA11 / BACT, PA 5T / 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 and PA 5T / 10T.

[0129] Advantageously, the multilayer structure comprises a single reinforcing layer and a single sealing layer, wherein the polymer P1i is a long-chain aliphatic polyamide, in particular, PA1010, PA1012, PA1212, PA11, PA12, in detail, PA11 or PA12, and the polymer P2j is a semi-aromatic polyamide, in particular, selected from PA MPMDT / 6T, PA PA11 / 10T, PA11 / BACT, 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.

[0130] Advantageously, the above multilayer structure is a flexible pipe.

[0131] The maximum operating temperature (Tu) of the above multilayer structure is greater than 50℃, in particular, greater than 100℃.

[0132] In one embodiment, the multilayer structure defined above has pressure resistance and drying ability.

[0133] In practice, when storing or transporting gas, the gas can diffuse through the sealing layer(s) from the inside of the tube or reservoir to the interface between the final sealing layer and the first composite reinforcement due to the permeability of the sealing layer(s) to the transported or stored gas. At this location, the accumulation of gas can generate pressure leading to the collapse of the sealing layer(s) when the internal pressure of the tube or reservoir is lower than the pressure at the interface with the composite reinforcement, which can occur particularly when the pumping or transport of gas is stopped during production shutdowns that drop pressures of several hundred bar to atmospheric pressure, or when the storage reservoir is empty. The same applies to internal hydrostatic testing of the reservoir. This water is prone to moving by permeation at the interface between the composite reinforcement and the final sealing layer and will be very difficult to subsequently remove, which results in long and expensive drying cycles of the storage reservoir, particularly under vacuum.

[0134] In another embodiment, the multilayer structure defined above further comprises a metallic carcass located within the sealing layer.

[0135] This metallic carcass is not for leak prevention, but is the innermost layer.

[0136] Advantageously, the multilayer structure further comprises at least one outer layer, specifically, a metallic layer, said layer being the outermost layer of the multilayer structure.

[0137] The above outer layer is a second reinforcing layer, but it is metallic and not a composite.

[0138] In addition, a polymer protective layer (outermost layer) may exist on the structure, which may serve as an anti-wear agent or be imprinted on the substrate. Regarding fibrous materials

[0139] Regarding the fibers constituting the above fibrous material, these are, in particular, mineral, organic, or plant fibers.

[0140] Advantageously, the fibrous material may or may not be sized.

[0141] Accordingly, the above fibrous material may include an organic material (thermosetting or thermoplastic resin type) referred to as sizing in an amount of up to 0.1 weight%.

[0142] Among fibers of mineral origin, carbon fibers, glass fibers, basalt fibers or basalt-based fibers, silica fibers, or silicon carbide fibers may be mentioned. Organic fibers include, for example, thermoplastic or thermosetting polymer-based fibers, for example, semi-aromatic polyamide fibers, aramid fibers, or polyolefin fibers. Preferably, these are amorphous thermoplastic polymer-based and have a glass transition temperature Tg that is higher than the Tg of the polymer or thermoplastic polymer mixture constituting the pre-impregnation matrix when the latter is amorphous, or higher than the Tm of the polymer or thermoplastic polymer mixture constituting the pre-impregnation matrix when the latter is semicrystalline. Advantageously, these are semicrystalline thermoplastic polymer-based and have a melting temperature Tm higher than the Tg of the polymer or thermoplastic polymer mixture constituting the pre-impregnation matrix when the latter is amorphous, or higher than the Tm of the polymer or thermoplastic polymer matrix mixture constituting the pre-impregnation matrix when the latter is semicrystalline. Accordingly, there is no risk of melting for the organic fibers constituting the fibrous material during impregnation by the thermoplastic matrix of the final composite. Plant fibers include natural linen, hemp, greenin, bamboo, silk, in particular, spider silk, sisal, and other cellulose fibers, in particular, viscose. These plant fibers may be used in their pure form, treated, or coated as a coating layer to facilitate adhesion and impregnation by the thermoplastic polymer matrix.

[0143] The fibrous material can also be a fabric, braid, or woven fiber.

[0144] This may also apply to fibers having a support thread.

[0145] These component fibers can be used alone or as a mixture. Accordingly, organic fibers can be pre-impregnated with thermoplastic polymer powder and mixed with mineral fibers to form a pre-impregnated fibrous material.

[0146] Organic fiber strands can have various basis weights. Additionally, they can have several geometric structures. The component fibers of the fibrous material can assume the form of a mixture of these reinforcing fibers having additionally different geometric structures.

[0147] Fiber is a continuous fiber.

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

[0149] More advantageously, the fibrous material is selected from carbon fibers, basalt fibers, and basalt-based fibers.

[0150] This is used in the form of roving or several rovings.

[0151] According to another aspect, the present invention relates to a method for manufacturing a multilayer structure defined above, characterized by comprising the step of welding a reinforcing layer defined above to a sealing layer defined above.

[0152] Advantageously, the welding step is performed by a system selected from laser, infrared heating, or induction heating.

[0153] Advantageously, the method comprises the steps of extruding a sealing layer onto a metallic carcass and welding a reinforcing layer onto the sealing layer.

[0154] According to another aspect, the present invention relates to the use of a storage pipe or tube for transporting or storing gas or utilizing it from an oil or gas deposit on the seabed, excluding the transport or storage of hydrogen, and a multilayer structure selected from a storage pipe or tube for transporting or storing gas, comprising at least one sealing layer defined above from the inside to the outside and at least one composite reinforcing layer defined above. The innermost composite reinforcing layer is welded to the outermost adjacent sealing layer, and The sealing layer is composed of a composition mainly comprising at least one semicrystalline thermoplastic polymer P1i (i=1 to n, where n is the number of sealing layers), and its Tm is less than 280°C, particularly less than 265°C, when measured according to ISO 11357-3: 2013. At least one thermoplastic polymer of each of the above sealing layers may be the same or different, and At least one of the above composite reinforcing layers is composed of a fibrous material in the form of continuous fibers impregnated with a composition mainly comprising at least one thermoplastic polymer P2j (j=1 to m, where m is the number of reinforcing layers), which is particularly semicrystalline, wherein the thermoplastic polymer P2j has a Tg exceeding the maximum operating temperature (Tu) of the structure when measured according to ISO 11357-3:2013, Tg ≥ Tu + 20°C, specifically, Tg ≥ Tu + 30°C (Tu is greater than 50°C, particularly greater than 100°C), and It relates to an application in which a multilayer structure selected from a storage tank, pipe, or tube for transporting or storing hydrogen is excluded. Specific details for implementing the invention Examples

[0155] In all embodiments, a reservoir was obtained by rotational molding of a liner at a temperature suitable for the properties of the thermoplastic resin used, except that in all cases it was less than 280°C.

[0156] The tube is obtained by extruding the liner at a temperature suitable for the properties of the thermoplastic resin used, but in all cases, it is less than 280°C.

[0157] In the case of epoxy, a wet filament winding process consisting of winding fibers around a liner was subsequently used, in which the fibers were pre-impregnated in a liquid epoxy bath. The storage was then polymerized in an oven for 2 hours.

[0158] In all other cases, a fibrous material (tape) pre-impregnated with a thermoplastic resin was used. This tape was deposited by filament winding at a speed of 12 m / min using a robot equipped with a 1500 W laser heater.

[0159] Example 1 (Comparative Example): Epoxy (Tg 130°C) - T700SC31E Flexible wastewater transport tube (coastal application) containing carbon fiber composite reinforcement and HDPE sealing layer: Immiscibility between the two resins preventing any welding between the fiber reinforcement and the sealing layer (see Table I).

[0160] Example 2: Type IV or V gas (natural gas) storage tank comprising BACT / 10T - T700SC31E carbon fiber composite reinforcement and PA6 sealing layer: Good partial miscibility between the two resins allowing good welding between the fiber reinforcement and the sealing layer (see Table 1)

[0161] Example 3: Type IV or V gas (natural gas) storage tank comprising BACT / 10T - T700SC31E carbon fiber composite reinforcement and PA66 sealing layer: Good partial miscibility between the two resins allowing good welding between the fiber reinforcement and the sealing layer (see Table 1)

[0162] Example 4: Flexible pipe used for pumping oil comprising BACT / 10T - T700SC31E carbon fiber composite reinforcement and PA11 sealing layer deposited on an internal metallic carcass: low partial miscibility between the two resins resulting in poor quality welding between the fiber reinforcement and the sealing layer (see Table 1).

[0163] Example 5: Flexible pipe used for pumping oil comprising 11 / BACT / 10T - T700SC31E carbon fiber composite reinforcement and PA11 sealing layer deposited on an internal metallic carcass: good partial miscibility between the two resins resulting in good welding between the fiber reinforcement and the sealing layer (see Table 1).

[0164] In all examples in Table 1 below, to evaluate the miscibility of the resins, mixtures were prepared from powders having a particle size of about 150 μm on a micro-DSM with a recirculation time of 1 minute after melting. All mixtures were produced at 300°C, except for the epoxy-polyethylene mixture prepared at 220°C.

[0165] At the end of the mixing process, the mixture was injected into a mold, and a test piece was prepared that is characterized by DMA. Table 1 Compatibility test results: - Column 4: Glass transition temperature of each resin before mixing - Column 5: Glass transition temperature of resin in mixture - Column 6: Ratio of the difference in glass transition temperatures between the mixture and the resin before mixing. 100% indicates the non-miscibility of the resin. < 80% indicates low miscibility. < 30% indicates good but partial miscibility. 0 indicates complete miscibility.

Claims

Claim 1 A multilayer structure selected from a storage tank, pipe, or tube for transporting or storing gas or utilizing it from an oil or gas deposit on the seabed, comprising at least one sealing layer and at least one composite reinforcing layer from the inside out, wherein the innermost composite reinforcing layer is welded to the outermost adjacent sealing layer, the sealing layer is composed of a composition comprising at least one semicrystalline thermoplastic polymer P1i (i=1 to n, where n is the number of sealing layers), the Tm of which is less than 280°C when measured according to ISO 11357-3:2013, the at least one thermoplastic polymer of each sealing layer may be the same or different, and at least one of the composite reinforcing layers is composed of a fibrous material in the form of a continuous fiber impregnated with a composition comprising at least one thermoplastic polymer P2j (j=1 to m, where m is the number of reinforcing layers), and the thermoplastic polymer P2j is measured according to ISO 11357-3:2013 A multilayer structure having a Tg that exceeds the maximum operating temperature (Tu) of the multilayer structure, wherein Tg ≥ Tu + 20°C (Tu is greater than 50°C), hydrogen is excluded from the gas transport or gas storage, and the multilayer structure selected from the storage, pipe or tube for transporting or storing hydrogen is excluded, and each polymer P1i of each sealing layer is partially or completely miscible with each polymer P1i of the adjacent layer(s), each polymer P2j of each reinforcing layer is partially or completely miscible with each polymer P2j of the adjacent layer(s), and polymer P21 is partially or completely miscible with the adjacent polymer P11, and the complete or partial miscibility of the polymers is defined by the difference in glass transition temperatures of the two resins in the mixture compared to the difference in glass transition temperatures of the two resins before mixing, wherein the difference is 0 when the miscibility is complete and the difference is not 0 when the miscibility is partial. Claim 2 delete Claim 3 A multilayer structure according to claim 1, characterized in that each sealing layer comprises the same type of polymer. Claim 4 A multilayer structure according to claim 1, characterized in that each reinforcing layer comprises the same type of polymer. Claim 5 A multilayer structure characterized in that, in paragraph 3, each sealing layer comprises the same type of polymer and each reinforcing layer comprises the same type of polymer. Claim 6 A multilayer structure according to claim 1, characterized by having a single sealing layer and a single reinforcing layer. Claim 7 A multilayer structure according to claim 1, characterized in that the multilayer structure is a flexible pipe. Claim 8 A multilayer structure according to claim 1, characterized in that the composition comprising polymers P1i and P2j also includes an additive that enables the absorption of radiation suitable for welding. Claim 9 A multilayer structure according to claim 1, characterized in that the composition containing the polymer P2j is transparent to radiation suitable for welding. Claim 10 A multilayer structure according to claim 8, characterized in that welding is performed by a system selected from laser, IR heating, or induction heating. Claim 11 A multilayer structure according to claim 1, characterized in that the polymer P1i is a polyamide. Claim 12 A multilayer structure according to claim 1, characterized in that the polymer P2j is a polyamide. Claim 13 A multilayer structure according to claim 11, characterized in that the polymer P1i and the polymer P2j are polyamides. Claim 14 A multilayer structure according to claim 11, characterized in that the polymer P1i is a long-chain aliphatic polyamide or semi-aromatic. Claim 15 A multilayer structure according to claim 12, characterized in that the polymer P2j is a semi-aromatic polyamide. Claim 16 A multilayer structure according to claim 13, characterized in that the polymer P1i is a long-chain aliphatic polyamide or semi-aromatic, and the polymer P2j is a semi-aromatic polyamide. Claim 17 A multilayer structure characterized by having pressure resistance and drying ability in claim 1. Claim 18 A multilayer structure according to claim 1, characterized in that the multilayer structure further comprises a metallic carcass located within a sealing layer. Claim 19 A multilayer structure according to claim 1, characterized in that the multilayer structure further comprises at least one outer layer, wherein the layer is the outermost layer of the multilayer structure. Claim 20 A multilayer structure according to claim 1, characterized in that the fibrous material is selected from glass fibers, carbon fibers, basalt fibers, and basalt-based fibers. Claim 21 A method for manufacturing a multilayer structure as defined in any one of claims 1 and 3 to 20, characterized by including the step of welding a reinforcing layer defined in claim 1 onto a sealing layer defined in claim 1. Claim 22 A method according to claim 21, characterized in that the welding step is performed by a system selected from a laser, infrared heating, or induction heating. Claim 23 A method according to claim 21, characterized by including the step of extruding the sealing layer onto a metallic carcass and the step of welding a reinforcing layer onto the sealing layer.

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