Submarine pipeline intended for the transport of hydrocarbons and / or gas, method for preparing the submarine pipeline, use of a submarine pipeline, method for extracting hydrocarbons and use of a composition C comprising a non-delaminating mixture M of polymers.

Abstract

The application relates to an underwater pipe for transporting hydrocarbons and / or gases, the pipe comprising, from the outside to the inside: - at least one reinforcing layer; and - a inner polymeric sealing sheath comprising a layer of polymeric material sheathed around a metal armature, characterised in that the polymeric material of the layer of the inner polymeric sealing sheath is a composition C comprising a delamination-resistant polymer mixture M, wherein the mixture M comprises at least one pseudo-amorphous or semi-crystalline polyaryletherketone having a melting point that is less than or equal to 340°C, and a poly(etherimide-siloxane) copolymer, the application further relating to the preparation method thereof and to the uses thereof in the transportation of hydrocarbons and / or gases.

Description

"Submarine pipeline intended for the transport of hydrocarbons and / or gas, method for preparing the submarine pipeline, use of a submarine pipeline, method for extracting hydrocarbons and use of a composition C comprising a non-delaminating mixture M of polymers"

[001] The present invention relates to a submarine pipeline intended for the transport of hydrocarbons in deep water or for the transport of gas, typically CO2.

[002] These pipelines are likely to be used under high pressures, greater than 100 bar, or even 1,000 bar, and at high temperatures, greater than 130 °C, or even 170 °C, for long periods of time, i.e., several years, typically 20 years.

[003] Subsea pipelines intended for the transport of hydrocarbons or gas in deep water generally include at least one reinforcing layer around an inner polymer sealing sheath, in which the hydrocarbons or gases circulate.

[004] The material that constitutes the inner polymeric sealing sheath must be chemically stable and capable of mechanically resisting the transported fluid and its characteristics (composition, temperature, and pressure). The material must combine characteristics of ductility, weather resistance (generally, the piping must have a minimum service life of 20 years), mechanical strength, heat resistance, and pressure resistance. In particular, the material must be chemically inert with respect to the chemical compounds that constitute the transported fluid or exhibit aging kinetics compatible with the application.

[005] Various polymeric materials are used in the inner polymeric sealing sheath of a flexible submarine pipeline, for example: Petition 870250081006, dated 09 / 09 / 2025, page 72 / 139 2 / 60 - Polyethylene, particularly medium or high-density polyethylene, for low-temperature applications (typically below 90 °C). However, polyethylene is susceptible to blistering under certain conditions; - Polyamide (PA), especially polyamide 11. Unlike polyethylene, polyamide exhibits good resistance to bubble formation when subjected to pressure and temperature, as well as a low tendency to swell when in contact with petroleum-derived fluids. Polyamide is generally used for hydrocarbon transport conditions where the pressure is high and the temperature preferably remains below 90 °C, or even for temperatures that can reach 110 °C.

[006] On the other hand, one of the disadvantages of polyamide is that it tends to hydrolyze in the presence of water, which is frequently present in raw materials (chemical aging). Hydrolysis is rapid when subjected to temperatures (around 110 °C and above) and low pH values ​​(pH less than 7). Another disadvantage is its acquisition cost, which is significantly higher than that of polyethylene; Polyvinylidene fluoride (PVDF) possesses excellent chemical inertness. PVDF-based sheaths can withstand high pressures and operating temperatures up to 130°C-150°C.

[007] Its main disadvantage remains the price, which is much higher than that of polyethylene or polyamide.

[008] The use of thermoplastic materials in unbonded flexible piping is summarized in API RP 17B (2014) and API 17J (2014) published by the American Petroleum Institute.

[009] The use of the aforementioned polymeric materials is, however, limited due to their insufficient resistance to gas permeation, particularly CO2. Petition 870250081006, dated 09 / 09 / 2025, page 73 / 139 3 / 60

[0010] In fact, the hydrocarbons transported typically include crude oil, water, and pressurized gases, such as hydrogen sulfide (H2S) at a concentration generally on the order of 100 ppm, carbon dioxide (CO2) at a pressure of up to 100 bar (such pressures can be achieved by certain subsea wells that extract oil from pre-salt deposits), and methane (CH4) generally at a pressure between 1 bar and several hundred bar.

[0011] The amount of acidic species, such as CO2, inside the pipeline tends to increase due to gas reinjection in service, leading to high partial pressures of CO2 in the transported hydrocarbons.

[0012] Similarly, gas transport pipelines, and more specifically gas injection pipelines, mainly transport CO2, and CO2 permeation is also a problem.

[0013] Thus, flexible pipelines with an internal sealing sheath that prevents CO2 from penetrating the rest of the multilayer pipeline are traditionally used for various types of lines, such as those for gas injection operations, oil production, gas export and gas refueling.

[0014] These gases (H2S and / or CO2) can lead to the degradation of the reinforcement layers located outside the inner polymer sealing sheath. These reinforcement layers, often metallic or made of composite material, are typically tensile armor layers and / or a pressure chamber. A metallic reinforcement layer is particularly susceptible to stress corrosion cracking (SCC). In fact, under the conditions of use of the pipeline, at least one metallic reinforcement layer is subject to very high radial or longitudinal tensile stresses and is in a highly corrosive environment, particularly in the presence of CO2 and H2S. Stress corrosion causes the appearance of cracks and Petition 870250081006, dated 09 / 09 / 2025, page 74 / 139 4 / 60 degrades at least one reinforcing layer.

[0015] The use of an internal polymer sealing sheath with a barrier effect against gases likely to damage this reinforcement layer(s) allows for improved pipeline strength by reducing the ring composition and, in particular, improving the stress corrosion resistance of at least one reinforcement layer and, consequently, the pipeline service life.

[0016] The literature teaches that polyaryl ether ketones (PAEKs), and in particular polyether ketone ketones (PEKKs), exhibit low CO2 permeability. Blocking gas permeability requires a polymer whose chains have low mobility in the operating temperature range and which has the ability to crystallize after cooling.

[0017] However, the polymeric material of the inner polymeric sheath of a pipe is used in a temperature range significantly lower than its glass transition temperature. Due to the strong interchain bonds, polyaryletherketones are very rigid and their elongation at break, typically 1 to 8%, is often considered too low to permit their use as the polymeric material of the inner polymeric sheath of a flexible pipe. The required elongation at break is generally greater than 8%, preferably greater than 10%, in particular preferably greater than 15% or even greater than 20%. Therefore, a polyaryletherketone-based sheath does not possess the necessary flexibility to be used as the inner polymeric sheath of a flexible pipe for the intended applications.

[0018] The introduction of an elastomeric phase can reduce the stiffness and increase the flexibility of polyaryletherketone, provided that this elastomeric phase is well dispersed. Thus, to maintain low permeation, it is important to introduce a phase within the polyaryletherketone matrix. Petition 870250081006, dated 09 / 09 / 2025, page 75 / 139 5 / 60 finely dispersed impact modifier, which ensures compatibility on a micrometer scale and does not significantly impact the crystallization of the polyaryletherketone matrix.

[0019] But adding an impact modifier is not enough to prepare a polymeric inner sheath for flexible piping. In fact, another challenge is to successfully extrude the material in the form of a layer around the carcass, which is necessary for deep-sea applications, so that the piping can withstand external pressure. The crosshead extrusion process required for this operation demands a long residence time of the molten polymer. Therefore, the chosen formulation must be stable in the molten state for at least 5 minutes, preferably 10 minutes, and ideally up to 20 minutes.

[0020] Application WO 2019 / 150060 highlights the challenges of composing mixtures of poly(aryletherketone) and polysiloxane. It describes a polymer mixture comprising a poly(aryletherketone), a polysiloxane, and a polysiloxane block copolymer. This mixture exhibits good impact resistance, good elongation at break, and enhanced flexibility. The advantageous mechanical properties are related to the presence of the polysiloxane block copolymer, which ensures better dispersion of the polysiloxane within the poly(aryletherketone), acting as a surfactant. The composition in this application is described as usable for the manufacture of sheaths or tubes in pipelines in the petroleum industry.

[0021] Compositions consisting of a mixture of polyetherketoneacetone (PEKK), 3.75% to 7.5% by weight of a poly(etherimide-siloxane) copolymer and 3.5% to 7% by weight of polydimethylsiloxane are exemplified here. Petition 870250081006, dated 09 / 09 / 2025, page 76 / 139 6 / 60

[0022] The introduction of polydimethylsiloxane in high proportions has sometimes proven complicated to implement, due to the fact that polydimethylsiloxane can be in the form of a very viscous liquid, difficult to handle and to introduce in a well-controlled proportion into a composition. Furthermore, the addition of polydimethylsiloxane to a composition tends to reduce its barrier properties.

[0023] Finally, compared with the manufacture of conventional plastic parts, the particularity of extruding polymer sheaths for flexible piping lies in the fact that it is a continuous thick-walled extrusion process. This thickness can induce different cooling rates on the sheath surface or in the mass of the extruded sheath. Consequently, the crystallization kinetics of the polymer formulation should preferably allow a sufficient level of crystallization to be achieved to obtain the desired gas permeation.

[0024] One of the objectives of the present invention is to provide a submarine pipeline for the transport of hydrocarbons and / or gas (in particular CO2) whose internal polymeric sealing sheath presents a good compromise between low permeation to gas and in particular to CO2 and sufficient elongation at break, in particular in order to guarantee the flexibility of the sheath and therefore of the pipeline.

[0025] One of the objectives is to provide a submarine pipeline whose sheath has good suitability for preparation by extrusion, in particular a sheath whose polymeric material is stable in the molten state for at least 5 minutes.

[0026] For these purposes, according to a first object, the invention aims at a submarine pipeline intended for the transport of hydrocarbons and / or gas, comprising from the outside to the inside: - at least one reinforcing layer, Petition 870250081006, dated 09 / 09 / 2025, page 77 / 139 7 / 60 - an inner polymeric sealing sheath comprising a layer of coated polymeric material (“sheathed”) around a metallic housing, characterized in that the polymeric material of said inner polymeric sealing sheath layer is a composition C comprising a non-delaminating mixture M of polymers, the mixture M comprising: - at least 50% by weight of at least one pseudoamorphous or semicrystalline polyaryletherketone, said polyaryletherketone having a melting point of less than or equal to 340 °C, relative to the total weight of the mixture M; and, - 5% to 40% by weight of a poly(etherimida-siloxane) copolymer, relative to the total weight of the mixture M. Definitions

[0027] “Transport of hydrocarbons and / or gas” means the transport of hydrocarbons, gas or a mixture thereof. The gas is preferably CO2.

[0028] By “wrapped all around” we mean that the metal casing is coated with an inner polymer sealing sheath layer.

[0029] We understand that the term “thermoplastic polymer” refers to a polymer that becomes less viscous, or more liquid, or liquid when sufficiently heated, and that reversibly retains its thermoplasticity. Thermoplastic polymers are generally contrasted with thermosetting polymers, which irreversibly transform into an insoluble and non-moldable polymer network when heated.

[0030] We understand that the term “homopolymer” means a polymer made of a single repeating unit.

[0031] We understand that the term “copolymer” refers to a Petition 870250081006, dated 09 / 09 / 2025, p. 78 / 139 8 / 60 A copolymer is a polymer resulting from the copolymerization of at least two chemically different types of monomers, called comonomers. A copolymer is therefore formed by at least two repeating units derived from different monomers. It can also be formed by three or more repeating units derived from different monomers.

[0032] The copolymer may have a homogeneous structure, in particular of the statistical, alternating or random type, or a heterogeneous structure, in particular of the sequential or block type. In particular, the term “sequential copolymer” or “block copolymer” refers to copolymers in the sense mentioned above, in which at least two distinct homopolymer blocks are covalently linked. The length of the blocks may be variable. The blocks may consist of 1 to 1000, preferably 1 to 500, more preferably 1 to 100 and, in particular, 1 to 50 repeating units, respectively. The link between the two homopolymer blocks may be: a single covalent bond or a non-repetitive intermediate unit called a junction block.

[0033] We understand that “consisting essentially of unit(s)” means that the unit(s) represent a molar proportion of 95% to 99.9% in relation to the total number of moles of repeating units in the polymer.

[0034] We understand that “consisting of unit(s)” means that the unit(s) represent a molar proportion of at least 99.9%, in particular 100%, in the polymer relative to the total number of moles of repeating units in the polymer.

[0035] We understand that the term “non-delaminating polymer blend” refers to a macroscopically homogeneous polymer composition. The term encompasses, in particular, compositions composed of phases that are immiscible with each other and dispersed on a micrometer or submicrometer scale. Petition 870250081006, dated 09 / 09 / 2025, page 79 / 139 9 / 60 The term "non-delaminating" refers, in particular, to the property of the polymeric composition or sheath that seals the piping of not exhibiting any visually observable separation into multiple layers, such as flaking or an onion skin effect.

[0036] We understand that the term “glass transition temperature”, denoted by Tg, means the temperature at which a polymer, at least partially amorphous, transitions from a rubbery state to a glassy state, or vice versa, as measured by differential scanning calorimetry (DSC) in accordance with NF ISO 11357-2:2020, in a second heating, using temperature ramps during heating and cooling at 20 °C / min. In the present application, when referring to a glass transition temperature, it refers more particularly, unless otherwise indicated, to the half-step glass transition temperature, as defined in this standard.

[0037] We understand that the term “melting temperature”, denoted by Tf, refers to the temperature at which a semicrystalline polymer transitions to the viscous liquid state, as measured by differential scanning calorimetry (DSC) in accordance with NF EN ISO 11357-3:2018, on the second heating, using a heating rate of 20 °C / min. In the present application, when reference is made to a melting temperature, it refers more particularly, unless otherwise indicated, to the peak melting temperature, as defined in this standard.

[0038] The term “pseudoamorphous” polymer refers to a polymer that does not exhibit melt endothermy, as measured by differential scanning calorimetry (DSC) according to NF EN ISO 113573:2018, on the second heating, using heating and cooling rates of 20 °C / min. The pseudoamorphous polymer is, however, capable of crystallizing after being heated to a temperature above its glass transition temperature, in particular to a temperature in the range of Tg+40 °C to Tg+110 °C. Petition 870250081006, dated 09 / 09 / 2025, p. 80 / 139 10 / 60 °C, for example, at Tg+75 °C, for a sufficient time, in particular for 10 to 30 minutes, for example, 20 minutes. Thus, the melting temperature can also be measured on the second heating for pseudoamorphous polymers, proceeding as follows: - 1st heating according to a ramp of 20 °C / min until a plateau temperature in the range of Tg+40 °C to Tg+110 °C, for example at Tg+75 °C, for a sufficient duration, in particular for 10 to 30 minutes, for example 20 minutes, in particular at Tg+75 °C for 20 minutes; - Cooling at a rate of 20 °C / min to room temperature; - 2nd heating ramp at 20 °C / min.

[0039] We understand that the term “tensile modulus of elasticity”, or more simply “elastic modulus” or “modulus of elasticity”, is understood as the slope of the stress-strain curve σ(ε) in the interval between the two strains ε1 = 0.05% and ε2 = 0.25%, as defined in ISO 527-1:2019. The modulus of elasticity is expressed here in gigapascals (GPa). The slope is preferably measured by a linear regression method. Although the modulus of elasticity is determined here by a tensile mechanical load, the measurement can be made from other types of load, for example, in bending or compression.

[0040] We understand that “nominal strain” means the strain calculated from the displacement of the grips and the clamping distance of the test apparatus, as defined in ISO 527-1:2019. We understand that “nominal strain at break” or “elongation at break” means the strain at the last recorded point before the stress is reduced to a value less than or equal to 10% of the strength when failure occurs after the yield point, as defined in ISO 527-1:2019. It is expressed as a dimensionless ratio or as a percentage (%). Petition 870250081006, dated 09 / 09 / 2025, page 81 / 139 11 / 60

[0041] The actual measurement of the modulus of elasticity and nominal strain at rupture corresponds to the average of five tests performed consecutively. These tests can, for example, be performed using an MTS 810® device, marketed by MTS Systems Corporation, equipped with a mechanical extensometer.

[0042] We understand that the term “Charpy impact resistance”, or more simply “impact resistance”, refers to the impact resistance of 80 x 10 x 4 mm3 bars with type A notches, measured according to ISO 179:2010. The actual measurement corresponds to the average of 10 tests performed consecutively. A notch (V-shaped with a lower radius of 0.25 ± 0.05 mm) can be implemented in a device specially designed for this purpose (Automatic Notchvis Plus), marketed by Ceast). The bars are then left to rest for 24 hours. The impact resistance measurement can be performed on a Zwick 5102 impact testing machine.

[0043] Generally, those skilled in the art use the term “gas permeation” for a sheath or layer and “gas permeability” for a material, but these two expressions refer to the same property. For the purposes of this application, the term “gas permeation” has been chosen. Gas permeability is normally measured following the API17J 2009 fluid permeability test method.

[0044] The singular forms “a / an” and “the” applied to constituents of compositions, such as polyaryletherketone with a melting point less than or equal to 340 °C, or poly(etherimide-siloxane) copolymer, by default mean “at least one” and, respectively, “referred to by at least one”. The singular forms, however, include, without needing to be reminded each time, embodiments in which “a / an” means “a single” and “the” means “the only one”. Petition 870250081006, dated 09 / 09 / 2025, p. 82 / 139 12 / 60 POLYARYL TERKETONE

[0045] The non-delaminating polymer mixture M comprises at least 50% by weight of at least one polyaryletherketone with a melting point less than or equal to 340 °C, relative to the total weight of the mixture M.

[0046] The non-delaminating polymer mixture M may, in particular, comprise at least 60% by weight, or at least 70%, or at least 80% by weight, or at least 85% by weight of said at least one polyaryletherketone having a melting point less than or equal to 340 °C, relative to the total weight of the mixture M.

[0047] Optionally, mixture M may also comprise from 0% to 40% by weight of a polyaryletherketone with a melting point strictly above 340 °C as another thermoplastic polymer. Mixture M may, in particular, comprise more than 5% by weight of a polyaryletherketone with a melting point strictly above 340 °C as another thermoplastic polymer, relative to the total weight of mixture M. Mixture M (and preferably composition C) may, in particular, comprise less than 30% by weight, or less than 25% by weight, or less than 20% by weight, or less than 15% by weight, or even less than 10% by weight of a polyaryletherketone with a melting point strictly above 340 °C as another thermoplastic polymer, relative to the total weight of mixture M.

[0048] According to certain embodiments, mixture M does not comprise, and preferably composition C does not comprise, any other polyaryletherketone besides the aforementioned at least one polyaryletherketone having a melting point less than or equal to 340 °C.

[0049] A polyaryletherketone (PAEK) has the following formula units: (-Ar-X-) and (-Ar1-Y-), Petition 870250081006, dated 09 / 09 / 2025, p. 83 / 139 13 / 60 where: - Ar and Ari each denote a divalent aromatic radical; - Ar and Ari can be chosen preferably from 1,3-phenylene, 1,4-phenylene, 1,1'-divalent biphenylene at positions 3,3', 1,1'-divalent biphenyl at positions 3,4', 1,4-naphthylene, 1,5-naphthylene and 2,6-naphthylene; - X denotes an electron-withdrawing group; it may preferably be chosen from the carbonyl group and the sulfonyl group. - Y denotes a chosen group of an oxygen atom, a sulfur atom, an alkylene group, such as -(CH)2- and isopropylidene.

[0050] In these units X and Y, at least 50%, preferably at least 70%, and more particularly at least 80% of the X groups are a carbonyl group, and at least 50%, preferably at least 70%, and more particularly at least 80% of the Y groups represent an oxygen atom.

[0051] According to a preferred embodiment, 100% of the X groups denote a carbonyl group and 100% of the Y groups represent an oxygen atom.

[0052] Advantageously, the PAEK(s) can be chosen from: - a polyetherketone-ketone, also called PEKK; A PEKK comprises one or more formula units: -Ph-O-Ph-C(O)-PhC(O)-; - a polyether-ether-ketone, also called PEEK; a PEEK comprises one or more formula units: -Ph-O-Ph-O-Ph-C(O)-; - a polyether ketone, also called PEK; a PEK comprises one or more units of the formula: -Ph-O-Ph-C(O)-; - a polyether-ether-ketone-ketone, also called Petition 870250081006, dated 09 / 09 / 2025, page 84 / 139 14 / 60 A PEEKK comprises one or more formula units: -Ph-O-PhO-Ph-C(O)-Ph-C(O)-; - a polyetheretheretherketone, also called PEEEK; a PEEEK comprises one or more formula units: -Ph-O-PhO-Ph-O-Ph-C(O)-; - a poly-ether-diphenyl-ether-ketone also called A PEDEK comprises one or more formula units: -Ph-O-Ph-Ph-O-PhC(O)-; - mixtures thereof; and, - copolymers comprising at least two of the above-mentioned units, wherein: Ph represents a phenylene group and -C(O)- a carbonyl group, each of the phenylenes being independently of the ortho (1-2), meta (1-3) or para (1-4) type, preferably of the meta or para type.

[0053] In addition, defects, end groups and / or monomers may be incorporated in very small quantities into the polymers, as described in the list above, without affecting their performance.

[0054] According to certain embodiments, PAEK with a melting point less than or equal to 340 °C is a polyetherketoneacetone (PEKK) consisting essentially of, and preferably consisting of: a terephthalic repeating unit and, where appropriate, an isophthalic repeating unit, the terephthalic repeating unit (“T unit”) having the formula: [Chemistry 1] the isophthalic unit (“unit I”) with the formula: (I) Petition 870250081006, dated 09 / 09 / 2025, p. 85 / 139 15 / 60 [Chemistry 2] OO (II)

[0055] The mass ratio of T units relative to the sum of T and I units can vary from 0% to 100%. The choice of the molar ratio of T units relative to the sum of T and I units is one of the factors that allows adjusting the melting temperature, as well as the crystallization rate properties of polyether-ketones-ketones. A given molar ratio of T units relative to the sum of T and I units can be obtained by adjusting the respective concentrations of the reagents during polymerization, in a manner known per se. Preferably, the molar percentage of terephthalic units relative to the sum of terephthalic and isophthalic units is less than or equal to 74%, preferably from 0% to 5% or from 45% to 73%, and more preferably from 58% to 72%.

[0056] Preferably, the poly-ether-ketone-ketone has a homogeneous structure and may be, in particular, of the statistical type.

[0057] Poly-ether-ketone-ketones with a mass ratio of T units to the sum of T and I units less than or equal to 74% have a melting point less than or equal to 340 °C.

[0058] Preferably, a polyetherketone-ketone with a melting point less than or equal to 340 °C is chosen from polyetherketone-ketone with a mass ratio of T units relative to the sum of T and I units of 0% to 5% or 45% to 73%. The mass ratio of T units relative to the sum of T and I units may, in particular, be 0% to 5%, or 45% to 50%, or 50% to 55%, or 55% to 58%, or 58% to 62%, or 62% to 68%, or 68% to 72%.

[0059] More preferably, a poly-ether-ketone-ketone with Petition 870250081006, dated 09 / 09 / 2025, p. 86 / 139 16 / 60 a melting point less than or equal to 340 °C is chosen from polyether-ketone-ketone with a mass ratio of T units to the sum of T and I units of 58% to 72%.

[0060] The molar ratio of T units relative to the sum of T and I units may be, in particular, approximately 60% or approximately 70%. A polyether-ketone-ketone with a T:I ratio of about 60% is a pseudoamorphous polymer within the meaning of the present invention. A polyether-ketone-ketone with a ratio of about 70% is a semicrystalline polymer.

[0061] These poly-ether-ketone-ketones are commercially available under the name Kepstan® from the company Arkema.

[0062] According to certain embodiments, PAEK with a melting temperature less than or equal to 340 °C may be a PEEK-PEDEK copolymer consisting essentially of, or even consisting of, a repeating unit with the formula: [Chemistry 3] and a repeating unit with the formula: [Chemistry 4]

[0063] Copolymers consisting of repeating units of formula (III) and (IV) with a molar ratio of units (III) relative to the sum of units (III) and (IV) ranging from 5% to 45% have a melting temperature less than or equal to 340 °C.

[0064] According to certain embodiments, PAEK with a melting temperature less than or equal to 340 °C may be a copolymer that Petition 870250081006, dated 09 / 09 / 2025, p. 87 / 139 17 / 60 essentially consists of, or rather consists of, a repeating unit with formula (III) and a repeating unit with formula: [Chemistry 5]

[0065] Copolymers consisting of repeating units of formula (III) and (V) with a molar ratio of (III) units relative to the sum of (III) and (V) units ranging from 5% to 100% have a melting temperature less than or equal to 340 °C.

[0066] According to certain embodiments, PAEK with a melting temperature less than or equal to 340 °C may be a copolymer consisting essentially of, or even consisting of, a repeating unit with formula (III) and a repeating unit with formula:

[0067] Copolymers consisting of repeating units of formula (III) and (VI) with a molar ratio of units (III) relative to the sum of units (III) and (VI) ranging from 5% to 100% have a melting temperature less than or equal to 340 °C.

[0068] According to certain embodiments, PAEK with a melting point less than or equal to 340 °C has, in particular, a melting point less than or equal to 335 °C, or a melting point of Petition 870250081006, dated 09 / 09 / 2025, p. 88 / 139 18 / 60 melting point less than or equal to 330 °C, or a melting temperature less than or equal to 325 °C, or a melting temperature less than or equal to 320 °C. This has the advantage of limiting the thermal degradation of the poly(etherimidasiloxane) copolymer when the M blend is melted during its extrusion to form the inner polymeric sealing sheath at a maximum temperature of 5 °C to 40 °C above the melting temperature of PAEK with a melting temperature less than or equal to 340 °C, including for extended residence times in the melt.

[0069] In some embodiments, PAEK has a melting temperature greater than 275 °C, or greater than or equal to 285 °C, or greater than or equal to 295 °C. This has the advantage that the internal polymer sealing sheath has sufficient thermal resistance properties.

[0070] According to certain embodiments, the non-delaminating polymeric mixture M comprises two polyaryletherketones with a melting temperature less than or equal to 340 °C. The mixture M comprises a first polyaryletherketone P1, being a semicrystalline polymer with a melting temperature T1, and a second polyaryletherketone P2, being a semicrystalline polymer with a melting temperature such that T2 < T1, or a pseudoamorphous polymer.

[0071] According to certain embodiments, polymer P1 can represent at least 50% by weight of polyaryletherketones with a melting temperature less than or equal to 340 °C.

[0072] According to other embodiments, polymer P2 can represent at least 50% by weight of polyaryletherketones with a melting temperature less than or equal to 340 °C.

[0073] According to certain embodiments, P2 is a polyether-ketone-ketone consisting essentially of, and preferably consisting of: a terephthalic unit and an isophthalic unit, where the Petition 870250081006, dated 09 / 09 / 2025, p. 89 / 139 19 / 60 molar percentage of terephthalic units relative to the sum of terephthalic and isophthalic units from 0% to 5% or from 45% to 67%, and P1 is a poly-etherketone-ketone consisting essentially of, and preferably consisting of: one terephthalic unit and one isophthalic unit, the molar percentage of terephthalic units relative to the sum of terephthalic and isophthalic units being from 63% to 73%.

[0074] According to certain embodiments, P2 is a polyether-ketone-ketone consisting essentially of, and preferably consisting of: a terephthalic unit and an isophthalic unit, the molar percentage of terephthalic units relative to the sum of the terephthalic and isophthalic units being 58% to 67%, and P1 is a polyether-ketone-ketone consisting essentially of, and preferably consisting of: a terephthalic unit and an isophthalic unit, the molar percentage of terephthalic units relative to the sum of the terephthalic and isophthalic units being 63% to 73%. Advantageously, P2 represents at least 50% by weight of polyaryletherketones with a melting point less than or equal to 340 °C.

[0075] In embodiments wherein the mixture M further comprises a polyaryletherketone with a melting point strictly greater than 340 °C, the latter may be a PEEK homopolymer consisting of repeating unit (III); a PEEK-PEDEK copolymer consisting essentially of, or comprising, repeating units of formula (III) and formula (IV), the molar ratio of units of formula (III) to the total number of moles of units (III) and (IV) being strictly greater than 45%, in particular greater than or equal to 50%; or a PEKK consisting essentially of, or comprising, terephthalic (T) and isophthalic (I) repeating units, the molar ratio of terephthalic repeating units to the total number of moles of terephthalic and isophthalic repeating units being Petition 870250081006, dated 09 / 09 / 2025, p. 90 / 139 20 / 60 strictly greater than 74%, in particular greater than or equal to 75%, or greater than or equal to 76%, or greater than or equal to 77%, or greater than or equal to 78%.

[0076] According to certain embodiments, the mixture M comprises two polyaryletherketones P3 and P4, P3 being a semicrystalline or pseudoamorphous polyaryletherketone with a melting point less than or equal to 340 °C, preferably less than or equal to 320 °C, and P4 being a polyaryletherketone with a melting point strictly greater than 340 °C. Polymer P4 may represent, in particular, 25% by weight or less, 20% by weight or less, 15% by weight or less, or 10% by weight or less relative to the total weight of the mixture M.According to particular embodiments, polymer P3 may be a polyether-ketone-ketone consisting essentially of, and preferably consisting of: a terephthalic unit and an isophthalic unit, the molar percentage of terephthalic units in relation to the total number of moles of terephthalic and isophthalic units of the polyether-ketone being from 0% to 5% or from 45% to 67%, and polymer P4 may be a polyether-ketone-ketone consisting essentially of, and preferably consisting of: a terephthalic unit and an isophthalic unit, the molar percentage of terephthalic units in relation to the total number of moles of terephthalic and isophthalic units of the polyether-ketone-ketone being from 78% to 85%.

[0077] According to certain embodiments, mixture M comprises a polyether-ketone-ketone with a mass ratio of T units to the sum of T and I units of 78% to 85%. The molar ratio of T units to the sum of T and I units may, in particular, be about 80%. Such a polyether-ketone-ketone is commercially available under the name Kepstan® from the company Arkema.

[0078] According to certain embodiments, mixture M comprises a polyether-ketone-ketone consisting essentially of, and Petition 870250081006, dated 09 / 09 / 2025, p. 91 / 139 21 / 60 preferably consisting of: one terephthalic unit and one isophthalic unit, the molar percentage of terephthalic units in relation to the total number of moles of terephthalic and isophthalic units of the polyether-ether-ketone being from 0% to 5% or from 45% to 67%, and a polyether-ketone-ketone consisting essentially of, and preferably consisting of: one terephthalic unit and one isophthalic unit, the molar percentage of terephthalic units in relation to the total number of moles of terephthalic and isophthalic units of the polyether-ketone-ketone being from 78% to 85%.

[0079] Advantageously, mixture M comprises 25% by weight or less, 20% by weight or less, 15% by weight or less, or 10% by weight or less of said polyether-ketone-ketone with a molar ratio T / (T+I) of 78% to 85%, relative to the total weight of mixture M. POLY(ETHERIMIDE-SILOXANE) COPOLYMER

[0080] The poly(etherimide-siloxane) copolymer allows, in particular, to improve the toughness, flexibility, elongation at break and crack propagation resistance of composition C.

[0081] The polymer mixture M comprises from 5% to 40% by weight of a poly(etherimide-siloxane) copolymer, relative to the total weight of the mixture M.

[0082] Preferably, mixture M comprises less than 30%, and even more preferably less than 25% by weight of the poly(etherimide-siloxane) copolymer, relative to the total weight of the mixture.

[0083] According to certain embodiments, mixture M may comprise less than 20% by weight, or less than 17.5% by weight, or less than 15% by weight of the poly(etherimide-siloxane) copolymer, relative to the total weight of mixture M.

[0084] Preferably, mixture M comprises more than 7.5% by weight of the poly(etherimide-siloxane) copolymer, relative to the total weight of Petition 870250081006, dated 09 / 09 / 2025, page 92 / 139 22 / 60 mixture. Mixture M may, in particular, comprise more than 8.0% by weight of the poly(etherimide-siloxane) copolymer, relative to the total weight of mixture M.

[0085] According to certain embodiments, mixture M comprises from 5% to 8% by weight of the poly(etherimide-siloxane) copolymer, relative to the total weight of mixture M.

[0086] According to certain embodiments, mixture M comprises from 8% to 15% by weight of the poly(etherimide-siloxane) copolymer, relative to the total weight of mixture M.

[0087] According to certain embodiments, mixture M comprises from 15% to 25% by weight of the poly(etherimide-siloxane) copolymer, relative to the total weight of mixture M.

[0088] Poly(etherimide-siloxane) copolymers comprise polyetherimide units and polysiloxane units, for example, 5 to 1000, or 10 to 500 etherimide units and siloxane units.

[0089] Polyetherimide units include structural units of formula (VII): [Chemistry 7] where each R is the same or different and represents a substituted or unsubstituted divalent organic group, such as a C6-20 aromatic hydrocarbon group or a halogenated derivative thereof, a linear or branched chain C2-20 alkylene group or a halogenated derivative thereof, a C3-8 cycloalkylene group or a halogenated derivative thereof, in particular a divalent group of formula (VIII): Petition 870250081006, dated 09 / 09 / 2025, p. 93 / 139 23 / 60 [Chemistry 8] where Q1 represents —O—, —S—, —C(O)—, —SO2—, —SO—, —CyH2y —, where y represents an integer from 1 to 5 or a derivative Petition 870250081006, dated 09 / 09 / 2025, p. 94 / 139 24 / 60 halogenated of the same (which includes perfluoroalkylene groups) or —(ΟθH-ιο)ζ—, where z represents an integer from 1 to 4. In one embodiment, R is m-phenylene, p-phenylene, or diaryl sulfone.

[0090] Furthermore, in formula (VI), T represents —O— or a group of the formula —O—Z—O—, wherein the divalent bonds of the —O— group or the —O—Z—O— group are in the 3,3', 3,4', 4,3' or 4,4' positions. The Z group of —O—Z—O— may be a substituted or unsubstituted divalent organic group and may be a C6-24 aromatic monocyclic or polycyclic moiety optionally substituted by 1 to 6 C1-8 alkyl groups, 1 to 8 halogen atoms or a combination thereof, provided that the valence of Z is not exceeded. Examples of Z groups include groups derived from a dihydroxylated compound of formula (IX): [Chemistry 9] where Rae and Rb may be the same or different and represent, for example, a halogen atom or a monovalent C1-6 alkyl group; p and q each independently represent integers from 0 to 4; c represents 0 to 4; and Xa represents a linking group connecting the hydroxyl-substituted aromatic groups, the linking group and the hydroxyl substituent of each C6 arylene group being arranged in the ortho, meta, or para (more precisely, para) position relative to each other on the C6 arylene group. The linking group Xa may represent a single bond, —O—, —S—, —S(O)—, —S(O)2—, —C(O)— or a C1-18 organic linking group. The C1-18 organic linking group may be cyclic or acyclic, aromatic or non-aromatic, and may also comprise heteroatoms such as halogens, oxygen, nitrogen, Petition 870250081006, dated 09 / 09 / 2025, p. 95 / 139 25 / 60 sulfur, silicon, or phosphorus. The C1-18 organic group can be arranged so that the C6 arylene groups attached to it are each attached to a common alkylidene carbon or to carbons other than the C118 organic linking group.

[0091] A particular example of a Z group is a divalent group with formula (X): [Chemistry 10] (X) where Q represents —O—, —S—, —C(O)—, —SO2—, —SO— or —CyH2y—, where y represents an integer from 1 to 5 or a halogenated derivative thereof (including a perfluoroalkylene group). In a specific embodiment, Z represents a bisphenol A derivative, so that Q, in formula (X), is 2,2-isopropylidene.

[0092] In one embodiment of formula (VII), R represents m-phenylene or p-phenylene and T represents —O—Z—O—, where Z represents a divalent group of formula (X). Alternatively, R represents m-phenylene or p-phenylene and T represents —O—Z—O—, where Z represents a divalent group of formula (X) and Q represents 2,2-isopropylidene.

[0093] Polyetherimide blocks can be prepared by any of the methods well known to those skilled in the art, including the reaction of an aromatic bis(ether anhydride) of formula (XI): [Chemistry 11] Petition 870250081006, dated 09 / 09 / 2025, p. 96 / 139 26 / 60 with an organic diamine of formula (XII): H2N—R—NH2 (XII) where T and R are defined as described above. Polyetherimide copolymers can be produced using a combination of an aromatic bis(ether anhydride) of formula (XI) and a different bis(anhydride), for example, a bis(anhydride), where T does not contain ether functionality and, for example, T represents a sulfone.

[0094] Illustrative examples of bis(anhydrides) include 3,3-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride; 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl ether dianhydride; 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride; 4,4'-bis(3,4-dicarboxyphenoxy)benzophenone dianhydride; 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfone dianhydride; 2,2-bis[4-(2,3-dicarboxyphenoxy)phenyl]propane dianhydride; 4,4'-bis(2,3-dicarboxyphenoxy)diphenyl ether dianhydride; 4,4'-bis(2,3-dicarboxyphenoxy)diphenyl sulfide dianhydride; 4,4'-bis(2,3-dicarboxyphenoxy)benzophenone dianhydride; 4,4'-bis(2,3-dicarboxyphenoxy)diphenylsulfone dianhydride; 4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)diphenyl-2,2-propane dianhydride; 4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)diphenyl ether dianhydride; 4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride; 4-(2,3dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)benzophenone dianhydride;and the dianhydride of 4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)diphenylsulfone, as well as various combinations thereof.

[0095] Examples of organic diamines include ethylenediamine, propylenediamine, trimethylenediamine, diethylenetriamine, triethylenetetramine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, 1,12-dodecanodiamine, 1,18-octadecanodiamine, 3-methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine, 4-methylnonamethylenediamine, 5 Petition 870250081006, dated 09 / 09 / 2025, page 97 / 139 27 / 60 methylnonamethylenediamine, a 2,5-dimethylhexamethylenediamine, a 2,5 dimethylheptamethylenediamine, a 2,2-dimethylpropylenediamine, a N-methyl-bis(3aminopropyl)amine, a 3-methoxyhexamethylenediamine, a 1,2-bis(3aminopropoxy)ethane, or bis(3-aminopropyl)sulfide, a 1,4-cyclohexanediamine, or bis-(4-aminocyclohexyl)methane, a m-phenylenediamine, a p-phenylenediamine, or 2,4-diaminotoluene, or 2,6-diaminotoluene, a m-xylylenediamine, a pxylylenediamine, a 2-methyl-4,6-diethyl-1,3-phenylenediamine, a 5-methyl-4,6-diethyl-1,3 phenylenediamine, a benzidine, a 3,3'-dimethylbenzidine, a 3,3'-dimethoxybenzidine, a 1,5-diaminonaphthalene, bis-(4-aminophenyl)methane, bis(2-chloro-4-amino-3,5-diethylphenyl)methane, bis(4-aminophenyl)propane, 2,4-bis(p-amino-t-butyl)toluene, bis(p-amino-t-butylphenyl)ether, bis(p-methyl-o-aminophenyl)benzene, bis(p-methyl o-aminopentyl)benzene, 1,3-diamino-4-isopropylbenzene, bis(4-aminophenyl) sulfide, bis-(4-aminophenyl) sulfone, and bis(4-aminophenyl)ether. Combinations of these compounds may also be used. In some embodiments, the organic diamine is m-phenylenediamine, p-phenylenediamine, sulfonyldianiline, or a combination comprising one or more thereof.

[0096] Siloxane blocks contain units of the following formula (XIII): [Chemistry 12] (XIII) where each R' independently represents a C1-13 monovalent hydrocarbyl group and E is an integer from 1 to 100, notably from 2 to 50. For example, each R' may independently represent a C1-13 alkyl group, a C1-13 alkoxy group, a C2-13 alkenyl group, a C2-13 alkenyloxy group, a C3-6 cycloalkyl group, a C3-6 cycloalkoxy group, a C6-14 aryl group, a C6-10 aryloxy group, a group Petition 870250081006, dated 09 / 09 / 2025, pp. 98 / 139 28 / 60 arylalkyl C7-13, an arylalkoxy C7-13 group, an alkylaryl C7-13 group, or an alkylaryloxy C7-13 group. The above groups may be wholly or partially halogenated with fluorine, chlorine, bromine, or iodine, or a combination comprising at least one of these. In one embodiment, no bromine or chlorine is present, and in other embodiments, no halogen is present. Combinations of the above R' groups may be used in the same copolymer. In one embodiment, the polysiloxane blocks comprise R' groups with a minimum content of hydrocarbon radicals. In a specific embodiment, an R' group with a minimum content of hydrocarbon compounds is a methyl group.

[0097] Poly(etherimide-siloxanes) can be formed by the polymerization of an aromatic bisanhydride (XI) and a diamine component comprising an organic diamine (XII) as described above or a mixture of diamines and a polysiloxanediamine of the following formula (XIV): [Chemistry 13] (XIV) where R' and E are as described in formula (XIII), and each R4 independently represents a C2-C20 hydrocarbon moiety, in particular a C2-C20 arylene group, an alkylene or an arylenealkylene group. In some embodiments, R4 represents a C2-C20 alkylene group, more specifically a C2-C10 alkylene group, such as propene, and E has an average value of 5 to 100, 5 to 75, 5 to 60, 5 to 15 or 15 to 40. The procedures for preparing the polysiloxanediamines of formula (XIV) are well known in the art.

[0098] In certain poly(etherimide-siloxane) copolymers, the Petition 870250081006, dated 09 / 09 / 2025, p. 99 / 139 The 29 / 60 diamine component used in the preparation of the copolymers may contain 10 to 90 mol% (mol-%) or 20 to 50 mol% or 25 to 40 mol% of a polysiloxane diamine (XIV) and 10 to 90 mol% or 50 to 80 mol% or 60 to 75 mol% of the diamine (XII), for example, as described in US Patent No. 4,404,350. The diamine components may be physically mixed before reaction with one or more bisanhydrides, thus forming a substantially random copolymer. Alternatively, block or alternating copolymers may be formed by the selective reaction of (XII) and (XIV) with aromatic bis(ether) anhydrides (XI) to form polyimide blocks which are then reacted with each other. Thus, poly(etherimide-siloxane) copolymer can be a block, random, or graft copolymer. Poly(etherimide-siloxane) block copolymers comprise eterimide blocks and siloxane blocks in their polymer structure.Eterimide blocks and siloxane blocks may be present in random order, as blocks (i.e., AABB), alternating (i.e., ABAB), or in a combination thereof. Poly(etherimide-siloxane) graft copolymers are nonlinear copolymers comprising siloxane blocks connected to a linear or branched polymeric structure comprising eterimide blocks.

[0099] Examples of specific poly(etherimide-siloxanes) are described in US Patents Nos. 4,404,350, 4,808,686 and 4,690,997.

[00100] According to preferred embodiments, poly(etherimide-siloxane) consists essentially of, or consists of, units of formula (XV): [Chemistry 14] Petition 870250081006, dated 09 / 09 / 2025, pp. 100 / 139 30 / 60 wherein R' and E of the siloxane are as in formula (XIII), R and Z of the imide are as in formula (VII), R4 is the same as R4 as in formula (XIV), en is an integer from 5 to 100. In a particular embodiment, R represents phenylene, Z represents a bisphenol A residue, R4 represents n-propylene, E represents an integer from 2 to 50, or 5 to 20, or 6 to 15, n represents 5 to 100 and each R' of the siloxane is methyl.

[00101] The relative amount of polysiloxane units and etherimide units in the poly(etherimide-siloxane) depends on the desired properties and is selected using the guidelines provided in the present invention. In particular, the poly(etherimide-siloxane) copolymer is selected to have a certain average E value and is selected and used in a sufficient quantity to provide the desired weight percentage (% by weight) of siloxane units in the thermoplastic composition. In some embodiments, the polysiloxane block of the copolymer has a number average molecular weight (Mn) of 300 to 3,000 grams / mol (Daltons).

[00102] According to certain embodiments, the siloxane groups of the poly(etherimide-siloxane) copolymer represent more than 30% by weight, relative to the total weight of the poly(etherimide-siloxane) copolymer.

[00103] According to certain embodiments, the siloxane groups of the poly(etherimide-siloxane) copolymer represent more than 35% by weight, relative to the total weight of the poly(etherimide-siloxane) copolymer.

[00104] According to certain embodiments, the siloxane groups of the poly(etherimide-siloxane) copolymer represent less than 50% by weight, relative to the total weight of the poly(etherimide-siloxane) copolymer.

[00105] According to certain embodiments, the Petition 870250081006, dated 09 / 09 / 2025, pp. 101 / 139 31 / 60 siloxane groups of the poly(etherimide-siloxane) copolymer represent less than 45% by weight of the total weight of the poly(etherimide-siloxane) copolymer.

[00106] Polysiloxane / polyetherimide copolymers are commercially available under the name SILTEM® from the company Sabic. Another Thermoplastic Polymer

[00107] According to certain embodiments, the mixture M may comprise from 0% to 40% by weight of a thermoplastic polymer other than polyaryletherketone with a melting point less than or equal to 340 °C and of the poly(etherimide-siloxane) copolymer, relative to the total weight of the mixture M.

[00108] According to certain embodiments, the mixture M does not comprise, and preferably composition C does not comprise, any other thermoplastic polymer besides polyaryletherketone with a melting point of less than or equal to 340 °C and poly(etherimide-siloxane) copolymer.

[00109] Other thermoplastic polymers which may include polyaryletherketone with a melting temperature strictly above 340 °C, a polysiloxane, a fluoropolymer, a polyetherimide (PEI), a polyphenylene sulfone (PPSU), a polysulfone (PSU), a polycarbonate (PC), a polyphenylene ether (PPE), a poly(phenylene sulfide) (PPS), a poly(ethylene terephthalate) (PET), a polyamide (PA), a polybenzimidizole (PBI), a poly(amide-imide) (PAI), a poly(ether sulfone) (PES), a poly(aryl sulfone), a poly(ether imide sulfone), a polyphenylene, a polybenzoxazole, a polybenzothiazole or a mixture thereof.

[00110] According to certain embodiments, the other thermoplastic polymer may be, in particular, a polyaryletherketone with a melting temperature strictly greater than 340 °C, as described above.

[00111] According to certain forms of realization, the other Petition 870250081006, dated 09 / 09 / 2025, pp. 102 / 139 32 / 60 thermoplastic polymer can be, in particular, a polysiloxane. The polysiloxane can be mono- or disubstituted with alkyl and / or phenyl groups from C1 to C12, preferably from C1 to C6 and, more particularly, from C1 to C4. Preferably, the alkyl groups are methyl groups. The alkyl or phenyl groups of the polysiloxane can be substituted with one or more functional groups, such as epoxy, alkoxy, in particular methoxy, amine, ketone, thioether, halogen, nitrile, nitro, sulfone, phosphoryl, imino or thioester. These functional groups can also be located at the end of the polysiloxane chain. These functionalized polysiloxanes can be used for their reaction during mixing (reactive siloxanes).

[00112] Preferably, however, the polysiloxane does not have functional groups. In addition, the alkyl or phenyl groups of the polysiloxane can be replaced by one or more carbocyclic, aryl, heteroaryl, alkyl, alkenyl, bicyclic or tricyclic groups.

[00113] Preferably, the polysiloxane present in mixture M as another thermoplastic polymer is a poly(dimethylsiloxane) (PDMS). To facilitate handling, the polysiloxane can be combined with a solid support, such as silica, in particular fumed silica.

[00114] According to certain embodiments, the mixture M comprises from 0.1% to 3%, and preferably from 0.5% to 2% by weight of polysiloxane as another thermoplastic polymer relative to the total weight of the mixture M.

[00115] According to certain embodiments, the mixture M comprises less than 1% by weight of polysiloxane relative to the total weight of the mixture M.

[00116] Preferably, when mixture M comprises 5% to 7.5% by weight of a poly(etherimide-siloxane) copolymer, then mixture M (and preferably composition C) does not comprise polysiloxane. Petition 870250081006, dated 09 / 09 / 2025, pp. 103 / 139 33 / 60

[00117] According to certain embodiments, the mixture M does not comprise, and preferably composition C does not comprise, polysiloxane.

[00118] Preferably, composition C does not comprise any other thermoplastic polymer or, more generally, composition C does not comprise any other polymer besides those present in mixture C. Additives

[00119] Composition C may comprise from 0% to 40% by weight of one or more additives, preferably non-polymeric, relative to the total weight of composition C.

[00120] Advantageously, composition C comprises 0% to 30%, or 0% to 25%, or 1% to 20%, or 2% to 10% by weight of additives, relative to the total weight of composition C.

[00121] Among the additives, one or more fillers may be mentioned. Among the possible fillers, notably silica and alumina, nucleating fillers such as mineral fillers, in particular talc, carbon fillers, in particular carbon nanotubes or carbon blacks, ceramic fillers, in particular boron nitride (BN), or metal oxides, in particular ZnO or MgO, or reinforcing fillers such as glass fibers or carbon fibers may be mentioned. The crystallization kinetics of mixture M generally allows achieving the level of crystallization necessary to confer good resistance to CO2 permeation throughout the thickness of the sheath. Composition C may include additives capable of modifying (retarding or accelerating) its crystallization kinetics. These additives may thus facilitate obtaining the desired level of crystallization.Thus, according to specific embodiments, composition C may comprise from 0.1% to 5%, in particular from 0.25% to 2.5%, by weight, of a nucleating filler relative to the total weight of composition C. This allows for modification of the crystallization behavior of the polyaryletherketone(s) and, in. Petition 870250081006, dated 09 / 09 / 2025, pp. 104 / 139 34 / 60 in particular, increase the final crystallinity in usual processes for the formation of slower-crystallizing polyaryletherketones, without significantly modifying the processing conditions. These slower-crystallizing polyaryletherketones can, in particular, achieve sufficient crystallinity without, for example, the need for an additional annealing step.

[00122] According to certain embodiments, the polyaryletherketone of composition C can be a polyetherketone-ketone with a mass ratio of T units relative to the sum of T and I units less than or equal to 74%, and preferably from 0% to 5% or from 45% to 67%, and the nucleating charge can be a carbon filler. The polyaryletherketone of composition C can, for example, be a polyetherketone-ketone with a mass ratio of T units relative to the sum of T and I units ranging from 55% to 65%, in particular about 60%, and the carbon filler can be carbon nanotubes.

[00123] In addition, composition C may optionally contain smaller amounts, in particular less than 1% by weight relative to the total weight of composition C, of ​​functional additives. Examples that may be mentioned as such are antistatic agents, antioxidant agents, anti-UV agents, melt stabilizers, conductive agents, flame retardants, colorants and reactive agents such as alkaline carbonates.

[00124] Among the additives, one or more plasticizers may be mentioned, which can improve the cold performance of the sheath (reducing the glass transition temperature by 10 °C, or even 25 °C, measurable by DSC). The plasticizer may, for example, be chosen from the compounds defined in the Handbook of Plasticizers published by Georges Wypych.

[00125] Advantageously, composition C comprises between 0% to 20% by weight of plasticizer and, preferably, between 1% and 10% in Petition 870250081006, dated 09 / 09 / 2025, pp. 105 / 139 35 / 60 weight of plasticizer in relation to the total weight of composition C. Composition C

[00126] Composition C comprises a non-delaminating mixture M of polymers, wherein said mixture M comprises: - at least 50% by weight of at least one pseudoamorphous or semicrystalline polyaryletherketone, said polyaryletherketone having a melting point of less than or equal to 340 °C, relative to the total weight of the mixture; and, - 5% to 40% by weight of a poly(etherimide-siloxane) copolymer, relative to the total weight of the mixture.

[00127] According to certain embodiments, the mixture Composition M consists of at least one polyaryletherketone with a melting point of less than or equal to 340 °C, the poly(etherimide-siloxane) copolymer, and 0% to 40% by weight of another thermoplastic polymer other than polyaryletherketone and the poly(etherimide-siloxane) copolymer, relative to the total weight of mixture M. Preferably, composition C does not comprise any other thermoplastic polymer, or indeed any other polymer, besides those of mixture M.

[00128] According to certain embodiments, the mixture M consists of at least one polyaryletherketone and poly(etherimide-siloxane) copolymer. Preferably, composition C does not comprise any other thermoplastic polymer, or indeed any other polymer, besides those in mixture M.

[00129] Mixture M may constitute at least 60% by weight, or at least 70% by weight, or at least 75% by weight, or at least 80% by weight, or at least 85% by weight, or at least 90% by weight, in relation to the total weight of composition C.

[00130] According to certain embodiments, composition C comprises at least 60% by weight, preferably by Petition 870250081006, dated 09 / 09 / 2025, pp. 106 / 139 36 / 60 minus 70% by weight of mixture M and 0 to 40%, preferably 0 to 30% by weight of one or more additives, relative to the total weight of composition C.

[00131] Typically, composition C consists of: - 60 to 100% by weight, preferably 70 to 100% by weight, of mixture M as defined above, and - 0 to 40% by weight, preferably 0 to 30% by weight of additives, in relation to the total weight of composition C.

[00132] According to certain embodiments, composition C consists of mixture M and 0% to 30% by weight of additives, relative to the total weight of composition C.

[00133] According to certain embodiments, composition C consists of mixture M and 0% to 30% by weight of additives, including 0% to 20% by weight of plasticizer(s), 0% to 5% by weight of nucleating filler(s) and less than 1% by weight of functional additives, relative to the total weight of composition C. According to certain embodiments, composition C consists of mixture M, 0.1% to 5% of nucleating filler(s) and less than 1% of functional additives, relative to the total weight of composition C.

[00134] Properties of composition C and therefore of the inner polymeric sealing sheath layer of the pipe whose polymeric material is of composition C

[00135] The inner polymeric sealing sheath layer of the pipeline whose polymeric material is of composition C has a low permeability to gas and in particular to CO2. Typically, the inner polymeric sealing sheath layer of the pipeline whose polymeric material is of composition C has a CO2 permeability measured at 60 °C of less than 1.1x10-8 (cm3(STP).cm) / (cm2.s.bar). Petition 870250081006, dated 09 / 09 / 2025, pp. 107 / 139 37 / 60

[00136] The crystallinity levels of composition C allow for this good resistance to CO2 permeation. Composition C can exhibit different levels of crystallinity, which are particularly controllable by the crystallization kinetics of composition C. The modification of the crystallization behavior can be controlled, in particular, by the use of a mixture of polyaryletherketones in composition C and / or by the addition of an additive to composition C.

[00137] These crystallinity levels can be evaluated by DSC on the first heating at 20 °C / min, calculating: ΔHα-ΔHοο. The term 'ΔHcc' corresponds to the cold enthalpy of crystallization and the term 'W' corresponds to the enthalpy of fusion on the first heating at a heating rate of 20 °C / min. These enthalpies are expressed in Joules per gram of composition.

[00138] The expression ΔHα-ΔHοο can have a value generally ranging from 0 to 50 J / gram of composition C. In particular, it can have a value of 0 to 5 J / g, or 5 J / g to 10 J / g, or 10 J / g to 15 J / g, or 15 J / g to 20 J / g, or 20 J / g to 25 J / g, or 25 J / g to 30 J / g, or 30 J / g to 35 J / g, or 35 J / g to 40 J / g, or 40 J / g to 45 J / g, or 45 J / g to 50 J / g.

[00139] Composition C, and therefore the inner polymeric sealing sheath layer of the pipe whose polymeric material is composition C, generally presents itself as a heterophasic, but non-delaminating, composition. In fact, most often the poly(etherimidasiloxane) copolymer is poorly miscible in poly(aryletherketone). A dispersed phase in the form of continuous-phase nodules is then observed under electron microscopy. Preferably, the nodules have an average diameter of less than 20 µm, advantageously less than 10 µm, and very particularly less than 5 µm.

[00140] Preferably, poly(aryletherketone) forms the continuous phase (also called the matrix) of composition C and the copolymer of Petition 870250081006, dated 09 / 09 / 2025, pp. 108 / 139 38 / 60 poly(etherimide-siloxane) forms the dispersed phase.

[00141] The poly(etherimide-siloxane) copolymer improves the toughness, flexibility, elongation at break, and crack propagation resistance of composition C and, therefore, of the inner polymeric sealing sheath layer of the pipeline whose polymeric material is composition C. These enhanced properties allow for extending the service life of the inner polymeric sealing sheath and the flexible pipeline. The increased flexibility of the sheath and its elongation at break allow for greater deformations and, consequently, facilitate the winding of the pipeline onto reels and / or carousels during storage and / or transport, as well as during its installation at sea.

[00142] Preferably, the flexibility of the piping is such that it is capable of undergoing at least 1000 cycles, where for each cycle, the inner polymeric sealing sheath layer, whose polymeric material is of composition C, undergoes a level of bending deformation ranging from -2% to +2%, without any degradation of the composition C layer being observed.

[00143] Preferably, the inner polymeric sealing sheath layer of the pipe, whose polymeric material is of composition C, has a tensile modulus of elasticity, measured according to ISO 527-1A:2019 at 20 °C, of ​​less than 4.0 GPa, typically less than 3.5 GPa, in particular less than 3.2 GPa, preferably less than 3.0 GPa.

[00144] Preferably, the inner polymeric sealing sheath layer of the pipe whose polymeric material is of composition C has a nominal strain at break measured in accordance with ISO 527-1A:2019 at 20 °C greater than 8%, typically greater than 10%, in particular greater than 15%, preferably greater than 20%.

[00145] Preferably, the inner polymeric sealing sheath layer of the pipe whose polymeric material is of composition C has Petition 870250081006, dated 09 / 09 / 2025, pp. 109 / 139 39 / 60 a Charpy impact resistance according to ISO 179-1:2010 / 1eA greater than 5 KJ / m2, preferably greater than 6 KJ / m2, more preferably greater than 7 KJ / m2 and most preferably greater than 8 KJ / m2.

[00146] Preferably, the inner polymeric sealing sheath layer of the pipe whose polymeric material is of composition C has a stress at yield, as measured by ISO 527-1A:2019 at 20 °C, of ​​less than 85 MPa.

[00147] Preferably, the inner polymeric sealing sheath layer of the pipeline, whose polymeric material is of composition C, resists five bubble cycles in a mixture of 85% CH4 - 15% CO2 at 520 bar and 110 °C after exposure to diesel at 100 °C for 15 days and / or resists one bubble cycle in 100% CO2 at 680 bar and 110 °C, with resistance to the bubble phenomenon evaluated according to the API 17J normative document, 2014 edition published by the American Petroleum Institute. Pipe Structure and Different Layers

[00148] The internal polymer sealing sheath of the flexible tubing is typically tubular, generally has a diameter of 50 mm to 600 mm, preferably 50 to 400 mm, and / or a thickness of 1 mm to 150 mm, in particular 4 to 15 mm, preferably 7 to 10 mm and / or a length of 1 m to 10 km.

[00149] Preferably, the inner polymeric sealing sheath layer, whose polymeric material is composition C, has a thickness greater than 3 mm, in particular greater than 4 mm, preferably greater than 5 mm, and most preferably greater than 6 mm. By “thickness” is meant the average thickness throughout the layer. Generally, the layer thickness is the same within ± 5%, typically within ± 2%, at any point in the layer. This thickness can be measured with a caliper.

[00150] The inner polymer sealing sheath Petition 870250081006, dated 09 / 09 / 2025, pp. 110 / 139 40 / 60 will likely be in contact with the hydrocarbons and / or gases being transported. By "internal polymeric seal sheath susceptible to hydrocarbon contact" it is understood that the sheath comes into contact with hydrocarbons when the pipeline is put into service. Therefore, the pipeline does not comprise an internal tubular layer (i.e., a hydrocarbon-tight layer) that opposes contact between the hydrocarbons and the sheath or layer. Typically, the pipeline does not comprise a polymeric tubular layer coated with the internal polymeric seal sheath or a hydrocarbon-tight metallic tube (a metallic casing is not such a metallic tube as it is not hydrocarbon-tight).

[00151] In one embodiment, the inner polymer sealing sheath is the only polymer layer within the reinforcement layer (or the innermost reinforcement layer when there are multiple reinforcement layers). However, the piping may include one or more additional polymer layers outside the reinforcement layer (or the innermost reinforcement layer when there are multiple reinforcement layers).

[00152] In one embodiment, the inner polymer sealing sheath is single-layered, which excludes multi-layered inner polymer sealing sheaths, regardless of whether the layers are not bonded or are bonded together, in particular by an adhesive or by being formed by co-extrusion. The polymeric material of the single-layer inner polymer sealing sheath is then composition C defined above. The inner polymer sealing sheath is then coated around the metal casing. A single layer, instead of two or more, prevents the accumulation of gas between the layers and therefore the degradation of the inner polymer sealing sheath by bubbles, for example, in the case of sudden, deliberate or unintentional depressurization of the subsea pipeline.

[00153] In another embodiment, the sealing sheath Petition 870250081006, dated 09 / 09 / 2025, pp. 111 / 139 41 / 60 internal polymeric sheaths are multilayered, typically bilayered. In addition to the layer whose polymeric material is of composition C, they comprise at least one other layer of polymeric material. The layer whose polymeric material is of composition C is the innermost layer of the internal polymeric sealing sheath. For example, the internal polymeric sealing sheath may comprise (or consist of) the layer whose polymeric material is of composition C as the innermost layer, and at least one other layer of polymeric material, whose composition is preferably different from that of the innermost layer. Preferably, the polymeric material of this at least one other layer is different from composition C and is, for example, chosen from polyolefins, in particular high-density or cross-linked polyethylene, polyamides, in particular PA 11, and fluorinated polymers, in particular PVDF.For example, the inner polymeric sealing sheath is two-layered and consists of an outer layer whose polymeric material is chosen from polyolefins, polyamides, and fluorinated polymers, and an inner layer whose polymeric material is of composition C as defined above.

[00154] Because the pipe comprises a metal casing, it is called a rough-bore pipe.

[00155] The main function of the metal casing is to absorb radial forces directed from outside to inside the pipeline, in order to prevent total or partial collapse of the pipeline under the effect of these forces. These forces are notably linked to the hydrostatic pressure exerted by seawater when the flexible pipeline is submerged. Thus, the hydrostatic pressure can reach a very high level when the pipeline is submerged at great depths, for example, 200 bar when the pipeline is submerged at a depth of 2,000 m, therefore, it is often essential to equip the flexible pipeline with a metal casing.

[00156] When the flexible tubing comprises a sheath Petition 870250081006, dated 09 / 09 / 2025, pp. 112 / 139 42 / 60 external polymeric sheath, the metal casing also serves to prevent the collapse of the internal polymeric sealing sheath during the rapid decompression of a flexible pipeline transporting hydrocarbons. In fact, the gases contained in the hydrocarbons diffuse slowly through the internal polymeric sealing sheath and become partially trapped in the annular space between the internal and external polymeric sealing sheaths. Consequently, during a production stoppage that causes rapid decompression of the interior of the flexible pipeline, the prevailing pressure in this annular space can temporarily become significantly greater than the prevailing pressure inside the pipeline, which, in the absence of a metal casing, would lead to the collapse of the internal polymeric sealing sheath.

[00157] The metal casing consists of helically wound longitudinal elements with a short pitch. These longitudinal elements are strips or wires of stainless steel arranged in coils stapled together. Advantageously, the metal casing is manufactured by profiling an S-shaped strip and then helically winding it to staple the adjacent turns.

[00158] The concept of short-pitch winding refers to any helical winding with a helix angle close to 90°, typically between 75° and 90°.

[00159] Generally, the reinforcement layer (or each reinforcement layer, when there are several) consists of a winding of at least one wire with non-contiguous turns. The wire is usually metallic or made of a composite material. Typically, at least one reinforcement layer consists of at least one layer of tensile armor or a pressure chamber.

[00160] The piping may comprise several layers of Petition 870250081006, dated 09 / 09 / 2025, pp. 113 / 139 43 / 60 reinforcement, usually an even number of tensile armor layers, typically two tensile armor layers, or a pressure chamber and two tensile armor layers.

[00161] Tensile armor layers consist of wires wound in long pitches and their main function is to absorb the axial forces linked, on the one hand, to the prevailing internal pressure inside the flexible pipe and, on the other hand, to the weight of the flexible pipe, especially when it is suspended.

[00162] In the present application, the concept of long-pitch winding covers any helical winding with a helix angle less than 60°, typically between 20° and 60° for shielding layers.

[00163] The presence of an additional reinforcement layer intended to absorb the radial forces associated with internal pressure, a layer notably called a “pressure chamber,” is not essential, since the helix angles of the wires that constitute the tensile armor layers are close to 55°. In fact, this specific helix angle gives the tensile armor layers the ability to absorb, in addition to axial forces, the radial forces exerted on the flexible piping and directed from the inside to the outside of the piping.

[00164] Preferably, and particularly for applications at great depths, in addition to the tensile armor layers, the flexible pipe comprises a pressure chamber interposed between the inner polymeric sealing sheath and the tensile armor layers. In this case, the radial forces exerted on the flexible pipe, in particular the radial forces directed from the inside to the outside of the pipe, are absorbed by the pressure chamber to prevent the inner polymeric sheath from rupturing under the effect of the prevailing pressure inside the pipe. The pressure chamber consists of short-pitch coiled longitudinal elements, for example, Petition 870250081006, dated 09 / 09 / 2025, pp. 114 / 139 44 / 60 metal wires or composite material in the shape of Z (zeta), C, T (theta), U, K or X, arranged in coils stapled together.

[00165] Advantageously, and in particular depending on the grade of metallic or composite material that constitutes the tensile armor layers and the possible pressure chamber, the flexible piping may comprise an external polymeric sealing sheath to prevent the penetration of seawater into the flexible piping. This allows, in particular, to protect the tensile armor layers from seawater and thus avoid the phenomenon of corrosion by seawater.

[00166] Typically, piping includes, from the outside in: - possibly an external polymer sealing sheath, - at least one layer of tensile armor as a reinforcing layer, usually an even number of tensile armor layers, typically two tensile armor layers, - possibly a pressure chamber, - the inner polymeric sealing sheath comprising the layer of polymeric material as defined above and encased around a metallic housing.

[00167] The piping may also include one or more additional polymer layers between two adjacent layers.

[00168] For example, the piping may comprise a retaining layer between the outer polymer sheath and the tensile armor layer (the outermost tensile armor layer when there are multiple tensile armor layers) or between two adjacent tensile armor layers.

[00169] The piping may also comprise one or more anti-wear layers made of polymeric material. The anti-wear layer may be in contact with the inner face of the layer of Petition 870250081006, dated 09 / 09 / 2025, pp. 115 / 139 45 / 60 retention mentioned, either with its outer face or with both faces, this anti-wear layer preventing wear of the retention layer in contact with the reinforcement. The anti-wear layer can also be between two adjacent reinforcement layers, for example, between the pressure chamber and the tensile reinforcement layer (the innermost tensile reinforcement layer when there are multiple tensile reinforcement layers), or between two adjacent tensile reinforcement layers.

[00170] Anti-wear layers are generally produced by helically winding one or more tapes obtained by extruding a polymeric material based on polyamide, polyolefins or PVDF (“polyvinylidene fluoride”). The tape may be made of polysulfone (PSU), polyethersulfone (PES), polyphenylsulfone (PPSU), polyetherimide (PEI), polytetrafluoroethylene (PTFE), polyetheretherketone (PEEK) or polyphenylene sulfide (PPS), as described, for example, in application WO 2006 / 120320.

[00171] The nature, number, size, and organization of the layers that make up flexible piping are essentially linked to their conditions of use and installation. Piping may include additional layers to those mentioned above.

[00172] In one embodiment, the flexible tubing is of the unbonded type, meaning that its reinforcing layers, such as the tensile armor layer(s) and / or the pressure chamber, are not bonded to the adjacent polymeric layer(s), such as the inner polymeric sealing sheath and / or the outer polymeric sealing sheath and / or any tubular polymeric layer that makes up the flexible tubing. By "unbonded" it is understood that the reinforcing layers are free to move relative to the polymeric layers. Typically, the reinforcing layers of the flexible tubing are not embedded in a polymeric or elastomeric sheath. Similarly, preferably there is no adhesive between the reinforcing layers and the Petition 870250081006, dated 09 / 09 / 2025, pp. 116 / 139 46 / 60 adjacent polymer layer(s).

[00173] In another embodiment, the flexible tubing is of the bonded type, that is, at least one of the reinforcing layers, often metallic or made of composite material, is bonded to an adjacent polymeric layer. If the reinforcing layer is interposed between two polymeric layers, only one or both faces of the reinforcing layer may be connected to the adjacent polymeric layer(s). If there are multiple reinforcing layers, each may be connected to an adjacent polymeric layer, by one face of the reinforcing layer or by both faces when the reinforcing layer is interposed between two polymeric layers. For example, the inner polymeric sealing sheath, whose composition layer C is coated around the metallic carcass, may be connected to the reinforcing layer (to the innermost reinforcing layer when there are multiple reinforcing layers).This bonding can be achieved by using an adhesive or elastomer between two adjacent layers, or by incorporating at least one face of the reinforcing layer into the adjacent polymeric or elastomeric sheath.

[00174] Flexible pipelines can be used at great depths, typically up to 3,000 meters. They allow the transport of fluids, especially hydrocarbons, with temperatures that typically reach 130 °C and even exceed 150 °C and internal pressures of up to 1,000 bar, or even 1,500 bar.

[00175] According to a second object, the invention relates to a method for preparing the subsea piping defined above, comprising the following steps: a) Extrusion to form the internal polymeric sealing sheath as defined above, with the extrusion being carried out on the metal casing, b) assembly of the internal polymer sealing sheath obtained in step a) with at least one reinforcing layer. Petition 870250081006, dated 09 / 09 / 2025, pp. 117 / 139 47 / 60

[00176] The use of a polyaryletherketone with a melting point of less than or equal to 340 °C makes composition C particularly suitable for extrusion molding into the form of an internal polymer sealing sheath. In fact, composition C is stable in the molten state for at least 5 minutes. The crystallization kinetics of composition C advantageously allows the achievement of the level of crystallization necessary to provide good resistance to CO2 permeation throughout the thickness of the sheath.

[00177] The extrusion step a) may be carried out by any method known to those skilled in the art, for example, using a single or twin screw extruder, and preferably a crosshead extrusion extruder.

[00178] The mixing of mixture M and other components it contains (additives, etc.) can be carried out before or during extrusion.

[00179] Preferably, the maximum temperature during extrusion should not exceed 350 °C, nor 345 °C, nor 340 °C, nor 335 °C. Generally, the maximum temperature during extrusion is set between 5 °C and 40 °C above the melting point of polyaryletherketone with a melting point less than or equal to 340 °C.

[00180] According to certain embodiments, the maximum temperature during the extrusion process is defined as 10 °C to 30 °C or 15 °C to 25 °C above the melting temperature of polyaryletherketone with a melting temperature of 340 °C or less.

[00181] A sufficiently low maximum temperature allows the extrusion of composition C in the form of a sheath, even for long residence times at or near the maximum extrusion temperature. This residence time in the extruder may, in particular, have an average duration of more than 1 minute, or more than 2 minutes. Petition 870250081006, dated 09 / 09 / 2025, pp. 118 / 139 48 / 60 or more than 3 minutes, or more than 4 minutes, or more than 5 minutes, or more than 10 minutes, or more than 20 minutes.

[00182] When the inner polymer sealing sheath is multilayered, it is preferably obtained by co-extrusion.

[00183] The method comprises step b) of assembling the internal polymeric sealing sheath obtained during step a) with the reinforcement layer(s) to form the flexible subsea pipeline.

[00184] The layers are then assembled to form a flexible subsea pipeline, for example of the unbonded type, as described in the normative documents published by the American Petroleum Institute (API), API 17J and API RP 17B.

[00185] According to a third object, the invention relates to a submarine pipeline capable of being obtained by the method mentioned above.

[00186] According to a fourth object, the invention relates to the use of said submarine pipeline for the transport of hydrocarbons and / or gas.

[00187] The submarine pipeline according to the invention is suitable for transporting gas, typically CO2, in particular with a view to its reinjection into the submarine reservoir from which hydrocarbons are extracted.

[00188] According to a fifth objective, the invention relates to the use of a composition C, as defined above, as a polymeric material for a layer of an inner polymeric sealing sheath, said layer being coated around a metallic casing of a submarine pipeline intended for the transport of hydrocarbons and / or gas and comprising at least one metallic reinforcement layer around said inner polymeric sealing sheath, to improve the stress corrosion resistance of said at least one metallic reinforcement layer. A Petition 870250081006, dated 09 / 09 / 2025, pages 119 / 139 49 / 60 stress corrosion can be evaluated using the NACE TM0177-2016-SG standard. The embodiments described above are, of course, applicable.

[00189] According to a sixth objective, the invention relates to the use of a composition C, as defined above, as a polymeric material of a layer of an inner polymeric sealing sheath, said layer being coated around a metallic casing of a submarine pipeline intended for the transport of hydrocarbons and / or gas and comprising at least one metallic reinforcement layer around said inner polymeric sealing sheath, to improve the permeation resistance of said inner polymeric sealing sheath. The embodiments described above are, of course, applicable.

[00190] According to a seventh object, the invention relates to a method for extracting hydrocarbons comprising: - the extraction of a mixture of hydrocarbons and CO2 from a submarine deposit, - the separation of hydrocarbons and CO2, - to transport at least some of the separated CO2 towards the aforementioned underwater storage facility in the pipeline as defined above, - the reinjection of the transported CO2 into the aforementioned underwater storage facility.

[00191] This process allows for a significant reduction in CO2 emissions during extraction and generally increases the amount of hydrocarbons that can be extracted from the subsea deposit.

[00192] The embodiments described above are, obviously, applicable.

[00193] Other features and advantages of the invention will emerge from reading the description given below of particular embodiments of the invention, provided for informational purposes, but not as a limitation. Petition 870250081006, dated 09 / 09 / 2025, pp. 120 / 139 50 / 60 with reference to the figures.

[00194] [Fig. 1] Figure 1 is a partial schematic perspective view of a flexible pipe according to the invention. It illustrates a pipe according to the invention, comprising, from the outside in: - an external polymer sealing sheath (10), - an outer layer of tensile armor (12), - an inner layer of tensile armor (14) wrapped in the opposite direction to the outer layer (12), - a pressure chamber (18) to absorb the radial forces generated by the pressure of the hydrocarbons or gases being transported, - an inner polymer sealing sheath (20) coated around an inner housing (22) to absorb radial crushing forces, wherein the polymer material of the inner polymer sealing sheath (20) is composition C as defined above.

[00195] Due to the presence of the inner casing (22), this pipe is said to have a rough bore.

[00196] The inner polymer sealing sheath (20) is single layer. Alternatively, it may be multilayer (not shown).

[00197] Similarly, it would not be outside the scope of the present invention to remove the pressure chamber (18), but the helix angles of the wires that constitute the shielding layers (12, 14) would then preferably be close to 55° and in opposite directions.

[00198] The armor layers (12 and 14) are obtained by long-pitch winding of a set of wires of metallic or composite material, generally of substantially rectangular cross-section. The invention would also apply if these wires had a cross-section of circular or complex geometry, for example, of the self-clamped T type. In Figure 1, only two armor layers (12 and 14) are shown, but the Petition 870250081006, dated 09 / 09 / 2025, pp. 121 / 139 51 / 60 piping may also include one or more additional pairs of armor. The armor layer (12) is called the outer layer because, in this case, it is the last one, starting from the inside of the piping, before the outer sealing sheath (10).

[00199] [Fig. 2] Figure 2 represents the mass loss of a sample of poly(etherimide-siloxane) copolymer (Siltem®STM 1500) obtained by thermogravimetric analysis (TGA) after heating under nitrogen at different temperatures for 1 hour. Examples Example 1: Preparation of extruded strips and evaluation of properties.

[00200] Granules containing a PAEK, a poly(etherimide-siloxane) copolymer and, optionally, an additive, the composition of which is detailed in Table 1, were used to prepare extruded strips. [Table 11] Composition PAEK PEKK (T / I ratio) % by mass of PAEK % by mass of PEI / PDMS3 Cup Additive4 % mass of additive 1c PEEK2 * 90 10 * 0 2 PEKK1 60 / 40 90 10 * 0 3 PEKK1 60 / 40 54 10 * 0 PEKK1 70 / 30 36 4 PEKK1 60 / 40 89.3 10 NTC 0.7 5 PEKK1 60 / 40 72 10 * 0 PEKK1 80 / 20 18 6c PEKK1 70 / 30 100 0 * 0 7c PEKK1 80 / 20 90 10 * 0 1: KEPSTAN® PEKK, 6000, 7000 and 8000 series grades, suitable for extrusion, marketed by Arkema. These polymers are PEKK copolymers with a T / I ratio of approximately 60 / 40 (pseudoamorphous with a melting temperature of 303 °C), 70 / 30 (semicrystalline with a melting temperature of 331 °C) and 80 / 20 (semicrystalline with a melting temperature of 355 °C), respectively. 2: PEEK 450G™, marketed by Victrex, suitable for Petition 870250081006, dated 09 / 09 / 2025, pages 122 / 139 52 / 60 extrusion (semicrystalline with a melting temperature of 343 °C),3: SILTEM® STM1500 copolymer of poly(etherimida-dimethylsiloxane) (PEI-PDMS), amorphous and with a glass transition temperature Tg of 168 °C. It has a mass proportion of 40% polydimethylsiloxane relative to the total weight of the polymer. It is marketed by the company Sabic,4: Carbon nanotubes (CNTs), GraphiStrength®C100, marketed by Arkema. Table 1: Composition of granules used for extrusion

[00201] A Collin single-screw extruder with a screw diameter of 30 mm and an L / D ratio of 25 was used. The extruder is connected to a flat die with a width of 50 mm and an air gap of 8 mm. At the die exit, the molten material is conveyed to a three-roll calendering system. The spacing between the rolls was adjusted just above the desired thickness to produce 7 mm thick strips. The strips were then cut to the desired length using a guillotine at the end of the line.

[00202] The extruder temperature conditions were as follows:

[00203] For the manufacture of composition strips 2, 3 and 4, a temperature profile was used with increasing temperatures up to the last zone and matrix at 320 °C.

[00204] To manufacture the composition strip 5, a bell-shaped temperature profile was used to obtain a homogeneous material and stable extrusion, with a defined maximum temperature of 335 °C and a final zone and die at 325 °C.

[00205] To manufacture the composition strip 1 c, a bell-shaped temperature profile was used to obtain a sufficiently homogeneous material and a sufficiently stable extrusion, with a defined maximum temperature of 370 °C and a final zone and die at 350 °C. Petition 870250081006, dated 09 / 09 / 2025, pp. 123 / 139 53 / 60

[00206] To manufacture the 6c composition strip, a bell-shaped temperature profile was used to obtain a sufficiently homogeneous material and a sufficiently stable extrusion, with a maximum set temperature of 350 °C and a die at 330 °C.

[00207] For all strips, the screw speed was set to 30 rpm and the overall line speed was approximately 0.2 m / min. The material residence time in the extruder to form 7 mm thick strips was estimated at approximately 3 to 4 minutes. Appearance of extruded strips

[00208] The composition strip 1c is delaminated (sheets visible in the section) and exhibits numerous porosities (numerous bubbles visible on the surface or in the section).

[00209] Unlike composition strip 1c, composition strips 2-5; 6c do not exhibit any delamination visible to the naked eye (smooth appearance in section) and do not exhibit any porosity (no visible bubbles on the surface or in section). Preparation of type 1A test specimens and type 1 bars, type A notch.

[00210] For the mechanical tests, type 1A test specimens and type 1A bars were manufactured subtractively by machining / milling, retaining only the core of the strips.

[00211] Due to the heterogeneous and delaminated nature of the composition strip 1c, it was not possible to produce correct samples / bars. Therefore, it was not possible to test it mechanically.

[00212] The dimensions and shape of the test specimens of the type 1A specimens are described in ISO 527-2:2012 (section 11 and Table 1, page 5). These test specimens are hereinafter referred to as “ISO 5272 / 1A test specimens”.

[00213] Type 1 bars have dimensions of 80.0 x 10.0 x Petition 870250081006, dated 09 / 09 / 2025, pages 124 / 139 54 / 60 4.0 mm³, as described in ISO 179-1:2010 (section 6.3, Table 1). They have a “V” notch (Type A notch) with a tip radius of 0.25 ± 0.05 mm. These bars are hereinafter referred to as “ISO 1791 / 1eA bars”.

[00214] The test specimens and notched bars were then left to stand for 24 hours at 23 °C and 50% relative humidity. Mechanical characterizations

[00215] ISO 527-2 / 1A samples were used to determine the modulus of elasticity and nominal strain at break at 23 °C and 50% RH of compositions 2-5 and 6c according to ISO 527-1:2019.

[00216] For the determination of the modulus of elasticity, a crosshead speed of 1 mm / min was used.

[00217] To determine the nominal strain at rupture, a crosshead speed of 50 mm / min was used.

[00218] ISO 179-1 / 1eA bars were used to determine the Charpy impact resistance of compositions 2-5 and 6c according to ISO 179-1:2010. Characterization of crystallinity

[00219] The crystallinity of the samples was evaluated by DSC on the first heating at 20 °C / min by the calculation: ΔH-ι-ΔHοο.

[00220] The results of the different characterizations are grouped in Table 2 below. [TABLE 2] Composition E(Gpa) ε (%) Charpy impact resistance with notch AHf1-AHCC (J / g) 2 2.8 37 9 0 3 2.8 > 50 10 7 4 2.9 16 11 14 5 3.2 24 9 24 6c 4.2 6 4 37 Petition 870250081006, dated 09 / 09 / 2025, pages 125 / 139 55 / 60

[00221] These examples demonstrate the benefit of using different PAEK compositions with a melting temperature of 340 °C or less and poly(etherimide-siloxane) copolymer, allowing for the extrusion forming of a sheath: - non-delaminated and homogeneous, even in the case of relatively long residence times at the extrusion temperature; - ductile, that is, with a relatively low modulus of elasticity, high nominal deformation at rupture, and high resistance to notched Charpy impact; - It can have a high thickness without losing the advantageous properties mentioned above.

[00222] Modification of crystallization behavior induced by i) the mixing of polyaryletherketones and / or ii) the addition of an additive results in sheaths that can exhibit good crystallinity while maintaining good ductility and flexibility. These levels of crystallization allow, in particular, improved chemical resistance and high barrier properties. Example 2: Preparation of a sheath by extrusion and evaluation of its properties.

[00223] Three types of pellets with composition 4, 5 or 7c of Table 1 above showed that the samples were dried in a dryer (Piovan) with a dew point of 40 °C for 48 hours at 180 °C. The moisture level was checked after drying with a moisture meter (Aquatrac) and was less than 50 ppm.

[00224] The pellets were then introduced at a temperature of 100 °C into a single-screw extruder (manufactured by Maillefer - 45 mm in diameter equipped with a three-zone screw), with a temperature profile as described in Example 1.

[00225] The residence time of the polymer composition in the molten state depends directly on the speed of the extruder screw and Petition 870250081006, dated 09 / 09 / 2025, pp. 126 / 139 56 / 60 can be calculated.

[00226] Various screw speeds were used and a significant impact of this speed (and therefore of the residence time in the molten state) on the surface appearance of the produced sheath was observed.

[00227] Table 3 shows that, depending on the composition used, the temperature of the extrudate obtained was different. Composition 4, which has the lowest melting temperature, showed a much better surface appearance, which is explained by the fact that the poly(etherimidasiloxane) copolymer was not degraded during extrusion. [Table 31] Extrudate temperature (°C) at 20 rpm Surface appearance at 30 rpm Extrudate temperature (°C) at 40 rpm Surface appearance at 40 rpm Composition 5 333 Slight signs of small scratches on the sheath surface 340 Smooth, slight residual scratches on the weld line Composition 4 315 Smooth 321 Smooth Composition 7c 350 Presence of defects and numerous surface scratches throughout the sheath 358 Presence of defects and numerous surface scratches throughout the sheath Table 3: Surface appearance of the sheath as a function of velocity. EXTRUDER SCREW

[00228] A 7 mm thick pressure sleeve can be extruded onto a metal housing, demonstrating the possibility of extruding a thick layer. Microscopic observations of the sheaths

[00229] Microscopic observations were made on the sheaths produced from compositions 4, 5, and 7c. Thin lamellae of 15 μm were obtained by sectioning with a microtome (Leica 2065) and observed under a digital microscope (Keyence VHX 700F). The area of ​​the weld line where the residence time of the polymeric composition in the molten state is known to be the longest was studied. Petition 870250081006, dated 09 / 09 / 2025, pages 127 / 139 57 / 60

[00230] Composition 5 showed a pronounced weld line without delamination, but probably with some microstructural singularities and possible slight degradation. Composition 4, on the other hand, shows practically no singularities in this area. Composition 7c shows clear signs of degradation around the entire circumference of the sheath, with bubbles in the first 0.2 mm below the outer surface of the sheath and, in addition, bubbles located on the weld line, indicating degradation related to residence time. Mechanical properties

[00231] Tensile test specimens were prepared and tensile tested at room temperature in accordance with ISO 527-1A from the extruded sheath.

[00232] All compositions used exhibit greater compliance compared to an unformulated polyether-ketone-ketone (used as a single component). The nominal strain at break is significantly greater than 10% for compositions 5 and 4. [Table 41] Modulus of elasticity (GPa) Nominal strain at rupture (%) Yield strength (MPa) Composition 5 3.3 21 85 Composition 4 2.8 35 79 Composition 7c5 3.6 19 97 5The test specimen prepared from an extruded sheath of composition 7c underwent a preparatory machining / milling operation before testing, in order to remove defects present on the surface (see Table 3) and allow the characterization of its mechanical properties. Table 4: Mechanical properties Flexibility

[00233] A prototype of 4-meter flexible piping Petition 870250081006, dated 09 / 09 / 2025, pages 128 / 139 A 58 / 60 length flexible tubing prototype, consisting of a metal casing around which a polymer sheath is extruded, was subjected to a bending test. For the test, the flexible tubing prototype is fixed and locked at one end, leaving it free to deform at the other end, allowing it to move through the cylinders of the test bench.

[00234] Bending and counter-bending stresses were applied sequentially, with the pipe returning to its natural unbent shape at the end of a cycle. The pipe, therefore, underwent a stress level that varied from -2% to +2% for each cycle, and this for 1,000 cycles, without any damage being observed in the polymer sheath. Resistance to the phenomenon of bubble formation.

[00235] Parts of the sheath made from composition 4 were cut, maintaining the total thickness of the sheath.

[00236] Two types of gas exposure tests followed by rapid decompression were performed.

[00237] In the first test, the samples were exposed to diesel for 15 days at 100 °C without significant swelling of the sheath. After this conditioning, the samples were exposed in an autoclave to a gas mixture of 85% CH4 - 15% CO2 at 520 bar and 110 °C for a minimum period of 72 hours, followed by rapid decompression of the gas at 70 bar / min. This cycle was repeated 5 times and, after removing the sample from the autoclave, the samples showed no signs of damage when observed under a microscope at 20x magnification.

[00238] In the second test, the samples were exposed to pure CO2 at 680 bar and 110 °C, followed by rapid gas decompression at 70 bar / min. After removal of the samples from the autoclave, they showed no signs of damage. Petition 870250081006, dated 09 / 09 / 2025, pages 129 / 139 59 / 60 Permeation resistance

[00239] Parts of the sheath made from composition 4 were prepared by machining to obtain thin membranes 1.5 mm thick from an area located in the core of the sheath's cross-section.

[00240] Permeation resistance was determined using the device for measuring the permeation coefficient of a sheath sample relative to a gas, as illustrated in Figure 2 and described from page 13, line 16 to page 15, line 2 of application FR 2 987 666. The method used is that described from page 15, line 7 to page 18, line 26 of this application, in which the gas used was pure CO2, the temperature was 80 °C and the pressure difference between the two sides of the membrane was 40 bar. Permeation resistance was calculated using equation [6] described on page 18, line 12 of this application. The values ​​obtained for composition 4 are less than 1.1x10-8 (cm3cm) / (cm2.s.bar). This represents a significant reduction compared to the reference pressure sheath materials considered, namely: - 2.9x10-7(cm3cm) / (cm2.s.bar) for MDPE 3802 polyethylene from TotalEnergies, - 1.2 x 10⁻⁷ (cm³ / cm) / (cm².s.bar) for Rilsan® PA11 polyamide BESNO P40 TL by Arkema, - 1.4 x 10⁻⁷ (cm³ / cm) / (cm².s.bar) for PVDF Kynar® 400 HDC M800 from Arkema, and - 2.39x10-8(cm3cm) / (cm2.s.bar) for PA9T GenestarTM N1006D H31 from Kuraray. Example 3: Thermal degradation of Siltem® STM 1500 as a function of temperature. [ 00241 ] The mass loss of a sample of poly(etherimide-siloxane) copolymer (Siltem® STM 1500) was determined by thermogravimetric analysis (TGA) after heating under nitrogen at different Petition 870250081006, dated 09 / 09 / 2025, pages 130 / 139 60 / 60 temperatures for 1 hour.

[00242] The results are given in Figure 2, which shows that below 350 °C, the mass loss (related to the thermal degradation of the copolymer) is low, even less than 1% up to 340 °C, but increases rapidly for temperatures above 350 °C.

[00243] This justifies the interest in a temperature for proceeding with the melt mixing of a composition comprising such a copolymer that remains less than or equal to 350 °C, preferably less than or equal to 340 °C.

Claims

1. SUBMARINE PIPELINE INTENDED FOR THE TRANSPORT OF HYDROCARBONS AND / OR GAS, characterized by comprising from the outside to the inside: - at least one reinforcing layer, and - an internal polymeric sealing sheath (20) comprising a layer of polymeric material coated around a metallic carcass, wherein the polymeric material of the internal polymeric sealing sheath layer (20) is a composition C comprising a non-delaminating mixture M of polymers, the mixture M comprising: - at least 50% by weight of at least one pseudoamorphous or semicrystalline polyaryletherketone, the polyaryletherketone having a melting point of less than or equal to 340 °C, relative to the total weight of the mixture M; and, - from 5% to 40% by weight of a poly(etherimida-siloxane) copolymer, relative to the total weight of the mixture M.

2. PIPING, according to claim 1, characterized in that the polyaryletherketone has a melting point less than or equal to 340 °C, or has a melting point less than or equal to 335 °C, or less than or equal to 330 °C, or less than or equal to 325 °C, or less than or equal to 320 °C.

3. PIPING, according to any one of claims 1 to 2, characterized by mixture M comprising less than 15% by weight, preferably less than 10% by weight, of a polyaryletherketone having a melting point strictly greater than 340 °C relative to the total weight of mixture M.

4. PIPING, according to any one of claims 1 to 3, characterized in that mixture M comprises more than 7.5% by weight, and preferably more than 8% by weight, of the poly(etherimide-siloxane) copolymer, and / or mixture M comprises less than 30%, preferably less than 25% by weight of the poly(etherimide-siloxane) copolymer, relative to the total weight of mixture M.

5. PIPING, according to any one of claims 1 to 4, characterized in that, when mixture M comprises from 5% to 7.5% by weight of a poly(etherimide-siloxane) copolymer, then composition C does not comprise polysiloxane.

6. PIPING, according to any one of claims 1 to 5, characterized in that composition C does not comprise polysiloxane.

7. PIPING, according to any one of claims 1 to 6, characterized in that the inner polymeric sealing sheath layer (20) whose polymeric material is of composition C has a thickness greater than 3 mm, in particular greater than 4 mm, preferably greater than 5 mm, and more particularly preferably greater than 6 mm.

8. PIPING, according to any one of claims 1 to 7, characterized by the inner polymeric sealing sheath layer (20) of the piping, the polymeric material of which is composition C: - having a CO2 permeation measured according to API 17J:2009 at 60 °C of less than 1.1x10-8 (cm3(STP).cm) / (cm2s.bar), and / or - having a tensile modulus of elasticity, measured according to ISO 527-1A:2019 at 20 °C, of ​​less than 4.0 GPa, typically less than 3.5 GPa, in particular less than 3.2 GPa, preferably less than 3.0 GPa, and / or - having a nominal strain at break, measured according to ISO 527-1A:2019 at 20 °C, greater than 8%, typically greater than 10%, in particular greater than 15%, preferably greater than 20%, and / or Petition 870250081006, dated 09 / 09 / 2025, p.133 / 139 3 / 5 - have a Charpy impact resistance according to ISO 179-1:2010 / 1eA greater than 5 kJ / m2, preferably greater than 6 kJ / m2, more preferably greater than 7 kJ / m2 and most preferably greater than 8 kJ / m2, - have a yield strength, measured according to ISO 527-1A:2019 at 20 °C, less than 85 MPa, and / or - withstand five blistering cycles in a mixture of 85% CH4 - 15% CO2 at 520 bar and 110 °C after exposure to diesel at 100 °C for 15 days and / or withstand one blistering cycle in 100% CO2 at 680 bar and 110 °C, with blistering resistance assessed according to API 17J: 2014.

9. PIPING, according to any one of claims 1 to 8, characterized in that the inner polymeric sealing sheath (20) is of a single layer, the polymeric material of the single layer being composition C.

10. PIPING, according to any one of claims 1 to 8, characterized in that the inner polymeric sealing sheath (20) is multilayered, the inner polymeric sealing sheath (20) comprising, in addition to the layer whose polymeric material is of composition C, at least one other layer of polymeric material, preferably chosen from polyolefins, in particular high-density or crosslinked polyethylene, polyamides, in particular PA 11, and fluorinated polymers, in particular PVDF.

11. PIPING, according to any one of claims 1 to 10, characterized in that at least one reinforcing layer is at least one tensile armor layer (12, 14) or a pressure chamber (18).

12. PIPING, according to claim 11 characterized by comprising, from outside to inside: Petition 870250081006, dated 09 / 09 / 2025, page 134 / 139 4 / 5 - optionally an external polymeric sealing sheath (10), - at least one layer of tensile armor (12, 14), generally an even number of layers of tensile armor (12, 14), normally two layers of tensile armor (12, 14), - optionally a pressure chamber (18), - the internal polymeric sealing sheath (20) comprising the layer of polymeric material, as defined in any of claims 1 to 10, and coated around the metal casing.

13. METHOD FOR PREPARING SUBMARINE PIPING, as defined in any one of claims 1 to 12, characterized by comprising the following steps: a) extrusion to form the internal polymeric sealing sheath (20), as defined in any one of claims 1 to 10, the extrusion being carried out on the metal casing, b) assembly of the internal polymeric sealing sheath (20) obtained in step a) with at least one reinforcing layer.

14. METHOD, according to claim 13, characterized in that the maximum temperature during extrusion does not exceed 350 °C, or does not exceed 345 °C, or does not exceed 340 °C, or does not exceed 335 °C.

15. USE OF A SUBMARINE PIPELINE, as defined in any one of claims 1 to 12, characterized in that it is for the transport of hydrocarbons and / or gas, in particular CO2.

16. METHOD FOR EXTRACTING HYDROCARBONS, characterized by comprising: - the extraction of a mixture of hydrocarbons and CO2 from a subsea deposit, - the separation of hydrocarbons and CO2, Petition 870250081006, dated 09 / 09 / 2025, page 135 / 139 5 / 5 - the transport of at least part of the separated CO2 to the subsea deposit in the pipeline, as defined in any one of claims 1 to 12, - the reinjection of the transported CO2 to the subsea deposit.

17. USE OF A COMPOSITION C COMPRISING A NON-DELAMINATING MIXTURE M OF POLYMERS, the mixture M comprising: - at least 50% by weight of at least one pseudoamorphous or semicrystalline polyaryletherketone, the polyaryletherketone having a melting point of less than or equal to 340 °C, relative to the total weight of the mixture M; and, - from 5% to 40% by weight of a poly(etherimida-siloxane) copolymer, relative to the total weight of the mixture M, characterized as a polymeric material of a layer of an inner polymeric sealing sheath (20), the layer being coated around a metallic casing of a submarine pipeline intended for the transport of hydrocarbons and / or gas and comprising at least one metallic reinforcement layer around the inner polymeric sealing sheath (20), to improve the permeation resistance of the inner polymeric sealing sheath (20) and / or to improve the stress corrosion resistance of at least one metallic reinforcement layer.

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