Method for manufacturing a hollow body made of composite material with variable cross-section

Abstract

The invention relates to a method for manufacturing a hollow body made of composite material, said method comprising the following successive steps: i) Manufacturing an elongated, unconsolidated textile preform using a specific device, the elongated, unconsolidated textile preform having a constant cross-section along its entire length, ii) Co-consolidation in a mold of the textile preform obtained in the previous step with at least one part fitting into the textile preform, iii) Demolding the resulting composite part at a temperature lower than the crystallization temperature of the thermoplastic matrix, as well as on the hollow body. Figure for the abstract: Fig. 10

Description

Title of the invention: Method for manufacturing a hollow body made of composite material with variable cross-section Scope of the invention

[0001] The invention relates to a method for manufacturing a hollow body made of composite material and to this hollow body made of composite material. Technical background

[0002] The processes commonly used to manufacture composite parts based on reinforcing fibers and thermosetting or thermoplastic resins are numerous: infusion, injection, extrusion, pultrusion, powder coating, thermocompression, stamping, etc. There are also robotic processes such as AFP (Automated Process Fabrication) or filament winding, which allow the production of composite parts either directly from raw materials mixed in-line (fiber and resin) or from semi-finished products. Semi-finished products usable in AFP and filament winding, containing thermoplastic resins, can be thermoplastic prepregs.

[0003] Other innovative technologies make it possible to produce composite parts from prepregs (thermoplastics or thermosets), most of which are inspired by the textile industry. Examples include weaving or braiding, which generate 2D or 3D shapes that can be used to manufacture composite parts after assembling different individual composite elements.

[0004] The manufacturing processes for composite parts with an axis of revolution, existing at the industrial level such as wet filament winding, by winding of thermoplastic composite ribbons for example, are generally slow; either because of the long time required for the deposition of prepregs; or (or in addition) because of the polymerization (curing) times required for the polymerization of thermosetting resins for example.

[0005] In addition, heating processes are generally not optimized, either technically (LASER which tends to overheat thermoplastic composites for example), or economically (cooking time of several hours of thermoset composites in oven or autoclave therefore with high energy consumption in electricity and inert gas).

[0006] The quality of the composites obtained is often imperfect, due to the presence of porosity, linked to the low pressure applied during the implementation of the pre-impregnated resin fibers, when it comes to wet impregnation or during the in situ consolidation of thermoplastic composite tapes.

[0007] Moreover, and this is mainly the case with manual deposition processes but also With robotic processes, there can be significant loss of raw material during manufacturing. For example, there are minimum dimensions that can be deposited using AFP or filament winding processes. There are also substantial minimum lengths required (several meters or even tens of meters per reel) to reach the deposition head from the unwinder (or canter), as this material is not actually used in the final part.

[0008] Finally, conventional manufacturing processes do not allow certain prepreg deposition geometries to be achieved because of either the excessive size of the processing equipment (dimension of the AFP deposition head for example) or because of the deposition angles which are not physically achievable without over-consuming material in the external areas of the tubular parts.

[0009] In the textile field, a method for manufacturing an elongated, unconsolidated textile element is known from document WO2023 / 089051.

[0010] The problem to be solved is to find an efficient manufacturing process, both technically (particularly in terms of mechanical performance) and economically (manufacturing cycle time, material or energy losses related to the manufacturing or assembly process, etc.), for manufacturing assembled parts with improved mechanical strength. These manufactured parts are 3D objects optimized in their design, performance, and cost.

[0011] The problem is more specifically aimed at obtaining a hollow body of geometry complex. Thus, rather than connecting existing pipes using joints, connectors, rings, or fittings of complex shapes that could potentially lead to leaks, the method according to the invention proposes, during the design of the component itself, these connected hollow bodies of different cross-sections. The assembly of these components is then carried out during the co-consolidation of the parts.

[0012] By complex geometry, we mean in the context of the present invention a part which may have different angles, and / or at least one non-planar surface, and / or variations in the internal distances of hollow parts, and / or changes in the shape of the sections in a hollow part.

[0013] A major advantage of the process is its productivity linked to the continuous manufacturing of the preform of the parts at a significant speed (typically 0.5 to Im / min in longitudinal tube production speed) as well as to consolidation in a closed mold (either fast, or in parallel with several molds).

[0014] Another advantage of the process is the ability to consolidate and assemble several tubes or parts at the same time in the same mold to manufacture parts with complex geometry in a reduced number of manufacturing steps, thus with a significant reduction in process times and energy savings.

[0015] Therefore, a simple, fast and inexpensive process is sought today to provide access to complex-shaped composite parts with good mechanical strength, particularly at high temperatures, and which are recyclable.

[0016] Today, complex-shaped composite parts with good mechanical strength, particularly at high temperatures, and that are recyclable are sought. Summary of the invention

[0017] This problem is solved by the process of the invention which comprises at least three steps: - A first step i) of manufacturing an elongated and unconsolidated textile preform, comprising several layers of thermoplastic composite ribbons, each layer comprising a ribbon wound at a given angle, without smearing, said preform being capable of being obtained from a specific device, represented in [Fig. 1]; the elongated and unconsolidated textile preform having a constant cross-section over its entire length, - A second co-consolidation step ii) in a mold of the textile preform obtained in the previous step with at least one piece fitting into the textile preform, - A third demolding stage iii).

[0018] This process has many advantages.

[0019] First of all, unlike processes involving braiding or weaving and which require going over the same layer to stack several layers of woven or braided ribbons, the manufacture of the preform according to step i) of the process of the invention can be carried out continuously, and therefore allows access in a quick and inexpensive way to large-sized textile preforms, in particular of small diameter with long lengths.

[0020] In addition, step i) of the process according to the invention allows a very large number of layers to be superimposed: the preform can contain as many layers of ribbon as there are modules implemented.

[0021] The device implemented in step i) uses guides to deploy the ribbons in the same direction. This allows for the production of elongated, cylindrical textile preforms. The preform can be easily bent at room temperature to give it a specific non-rectilinear shape, which is then fixed during the consolidation step ii). This will, however, require a specific choice of fiber orientations in the different layers of the preform.

[0022] Step ii) of co-consolidation allows, within a single step, the adhesion of thermoplastic or metallic inserts to the textile preform ribbons, making it possible to adapt the resulting composite part to other elements. Furthermore, This co-consolidation allows for improved mechanical resistance and / or cohesion between the insert and the co-consolidated composite part.

[0023] The process includes a demolding step iii) which must be carried out at a specific temperature in order not to damage the structure and shape of the final part obtained.

[0024] The invention thus relates, according to a first aspect, to a method for manufacturing a hollow body made of composite material, said method comprising the following successive steps: (i) Manufacture of an elongated, unconsolidated textile preform by means of a device (1) comprising: - a frame (2) comprising a main longitudinal guide (3) along a direction X, said guide (3) being fixed on the frame (2) and - at least two modules (4) arranged in series around the guide (3) along the X direction, each module (4) comprising: - a feed ring (5) surrounding a section of the guide (3), - feeding means (6) arranged on the ring (5) capable of feeding at least one ribbon (10) towards the guide (3) at a winding angle between -90° and 90° with the direction X and at a forward speed VI, each ribbon (10) being capable of winding at least around the guide (3) or over the upper layer of ribbon (10), and - drive means (15) for the crown (5) capable of rotating the crown (5) around the guide (3) at a rotational speed V2, The said preform is manufactured according to a process comprising the steps of: Implementation of the power supply means (6) on each of the modules (4), said power supply means (6) comprising selected ribbons (10), said selected ribbons (10) comprising at least thermoplastic composite ribbons Setting the forward speed VI and the rotation speed V2 of each of the modules (4) and starting up each module (4), Cutting of the elongated element (11) and / or exhaustion of the ribbons (10), and - Recovery of the elongated, unconsolidated textile preform (11) obtained; the elongated, unconsolidated textile preform having a constant cross-section over its entire length, (ii) Co-consolidation in a mold of the textile preform obtained in the previous step with at least one part fitting into the textile preform, (iii) Demolding of the composite part obtained at a temperature lower than the crystallization temperature of the thermoplastic matrix.

[0025] In embodiments, the method according to the invention comprises one or more of the following additional features: the heating step of step ü) is carried out at a temperature between a temperature equal to the melting temperature of the thermoplastic matrix + 5°C and the melting temperature of the thermoplastic matrix + 80°C, more particularly between a temperature equal to the melting temperature of the thermoplastic matrix + 10°C and the melting temperature of the thermoplastic matrix + 60°C. the heating step of step ii) is carried out at a pressure between 0.5 bar and 50 bar, in particular between 0.5 bar and 10 bar, in particular between 0.5 bar and 7 bar, in particular between 1 and 7 bar. a bending step is carried out before the consolidation step ii). Thermoplastic composite tapes include: • Reinforcing fibers, continuous or discontinuous, of an inorganic or natural material; and • A composition of thermoplastic polymers, the reinforcing fibers of an inorganic material are: • impregnated or pre-impregnated with a composition of thermoplastic polymers, or • mixed with thermoplastic polymer fiber(s). the thermoplastic polymer composition of the composite tape includes predominantly at least one thermoplastic polymer selected from: polyaryl ether ketones (PAEK), in particular poly(ether ether ketone) (PEEK); polyaryl ether ketone ketone (PAEKK), in particular poly(ether ketone ketone) (PEKK); polyaryl sulfones; polyaryl sulfides, in particular polyphenylene sulfides (PPS); polyamides (PA); PEBA, polyolefins, in particular polypropylene, polylactic acid (PLA), polyvinyl alcohol (PVA), and fluorinated polymers, in particular polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE) or polychlorotrifluoroethylene (PCTFE); and their mixtures, preferably, the thermoplastic polymer composition of the composite tape comprises predominantly a polyamide, preferably semi-crystalline. The thermoplastic polymer is an aliphatic, cycloaliphatic or semi-aromatic polyamide. the aliphatic polyamide is chosen from PA 5, PA5-10, PA6, PA66, PA6-10, PA6-12, PA6-18, PA9, PA10-10, PA 10-12, PAU, PA12, and their mixture and the semi-aromatic polyamide is chosen from PA MPMDT / 6T, PA 11 / 6T, PA 11 / 10T, PA 11 / BACT, PA 5T / 10T, PA 11 / 6T / 10T, PA MXDT / 4T, PA MXDT / 6T, PA MXDT / 10T, PA MPMDT / 4T, PA MPMDT / 6T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 4T, PA BACT / 10T / 6T, PA 11 / BACT / 4T, PA 11 / BACT / 6T, PA 11 / BACT / 10T, PA 11 / MXDT / 4T, PA 11 / MXDT / 6T, PA 11 / MXDT / 10T, PA 11 / MPMDT / 4T, PA 11 / MPMDT / 6T, PA 11 / MPMDT / 10T, PA 11 / MXDT / 10T, PA11 / 5T / 10T, and their mixture. - the fibers of the thermoplastic composite ribbons are chosen from glass fibers, carbon fibers, basalt or basalt-based fibers or are natural fibers such as flax fibers, reinforcements or bamboo fibers or hemp or cellulose fibers. - the fibers of thermoplastic composite tapes are unidirectional, that is to say all oriented along the length of the tape. - Composite ribbons contain a fiber content of between 40 and 70% by volume, preferably between 50 and 60% by volume of thermoplastic composite ribbons. - the selected ribbons (10) further include non-composite thermoplastic polymer ribbons (10). - the non-composite thermoplastic polymer ribbons (10) represent a minority mass fraction of the preform compared to the mass fraction of the thermoplastic composite ribbons. - the polymer composition constituting the non-composite thermoplastic ribbons (10) comprises mainly a polyamide, preferably semi-crystalline. - the thermoplastic polymer composition of the thermoplastic composite ribbons (10) on the one hand, and that of the non-composite thermoplastic polymer ribbons (10) on the other hand, are compatible, in particular identical. - the ribbons (10) have a thickness between 50 and 300 pm, in particular between 50 and 260 pm and more particularly between 60 pm and 170 pm. - the ribbons (10) have a width between 5 mm and 50 mm, in particular between 10 mm and 15 mm. - the winding angle of the ribbon (10) with respect to the X direction is between +90° and -90°. - step ii) pressure is applied by means of an internal bladder to the preform.

[0026] According to a second aspect, the invention relates to a hollow body made of composite material that can be obtained according to the process of the invention.

[0027] According to a third aspect, the invention relates to the use of the hollow body in the industrial field as a conduit for the transport of fluid and in the field of sport, in particular as an element of a sporting article, preferably a bicycle frame, a snowshoe frame, a ski pole, a trail running pole, a hockey stick, a golf club, a rowing element (rowing, canoeing, kayaking).

[0028] The inventors were able to show that the composite parts obtained according to the process of the invention exhibited very good mechanical resistance compared to composite parts of the prior art.

[0029] Indeed, unlike conventional methods involving braiding of composite ribbons, the process of the invention preferably allows winding of the ribbons without swagging, which makes it possible to avoid local over-stress at the points where the fibers cross each other, and therefore to improve the mechanical resistance of the elongated textile element obtained after consolidation.

[0030] Advantageously, the consolidation step ii) can be carried out under pressure, in particular under a pressure of between 5 and 10 bars, which makes it possible both to further improve the mechanical resistance and to reduce the porosity of the composite material.

[0031] Indeed, conventional processes using wet filament winding or winding of thermoplastic composite tapes do not allow for the application of high pressure, especially for a prolonged period, so that the quality of the consolidation is often quite low.

[0032] In addition, the inventors were able to observe that step ii) of consolidating the preform under pressure made it possible to give the resulting composite part a very low residual porosity, in particular less than 10%, in particular less than 5%, in particular less than 2%. Brief description of the figures

[0033] [Fig. 1] is a perspective view of an example of a device used in step i) of the process according to the invention,

[0034] [Fig.2] is a perspective view from an opposite angle of the device in [Fig.1],

[0035] [Fig.3] is a perspective view of an example module used in step i) of the method according to the invention,

[0036] [Fig.4] is a perspective view of the module of [Fig.3],

[0037] [Fig. 5] is a perspective view of an example of a ribbon feeding means used in step i) of the process according to the invention,

[0038] [Fig.6] is a perspective view of another example of an embodiment of a device used in step i) of the process according to the invention,

[0039] [Fig.7] is a perspective view from an opposite angle of the device in [Fig.6],

[0040] [Fig.8] is a front view of the elongated, unconsolidated textile preform,

[0041] [Fig.9] is a perspective view of the elongated, unconsolidated textile preform,

[0042] [Fig. 10] is a diagram representing the elongated, unconsolidated textile preform positioned in a mold and fitted into rings at each end,

[0043] [Fig. 11] is a perspective view of the final composite hollow body,

[0044] [Fig. 12] is a perspective view of an elongated, unconsolidated textile preform and fitted,

[0045] [Fig. 13] is a cross-sectional view of a final curved composite hollow body.

[0046] It should be noted that in these figures, the structural and / or functional elements common to the different variants may have the same references. Detailed description

[0047] The invention is now described in more detail and in a non-limiting manner in the following description.

[0048] Unless otherwise indicated, all percentages relating to quantities are volume percentages.

[0049] Method for manufacturing a hollow body made of composite material

[0050] According to a first aspect, the invention relates to a method for manufacturing a hollow body made of composite material of variable diameter / section, said method comprising the following successive steps:

[0051] (i) Manufacturing an elongated, unconsolidated textile preform using a device (1) comprising: - a frame (2) comprising a main longitudinal guide (3) along a direction X, said guide (3) being fixed on the frame (2) and - at least two modules (4) arranged in series around the guide (3) along the X direction, each module (4) comprising: - a feed ring (5) surrounding a section of the guide (3), - feeding means (6) arranged on the ring (5) capable of feeding at least one ribbon (10) towards the guide (3) at a winding angle between -90° and 90° with the direction X and at a forward speed VI, each ribbon (10) being capable of winding at least around the guide (3) or over the upper layer of ribbon (10), and - drive means (15) for the crown (5) capable of rotating the crown (5) around the guide (3) at a rotational speed V2, The said preform is manufactured according to a process comprising the steps of: Implementation of the power supply means (6) on each of the modules (4), said power supply means (6) comprising selected ribbons (10), said selected ribbons (10) comprising thermoplastic composite ribbons, Setting the forward speed VI and the rotation speed V2 of each of the modules (4) and starting up each module (4), Cutting of the elongated element (11) and / or exhaustion of the ribbons (10), and Recovery of the elongated unconsolidated textile preform (11) obtained; the elongated, unconsolidated textile preform having a constant cross-section along its entire length, (ii) Co-consolidation in a mold of the textile preform obtained in the previous step with at least one part fitting into the textile preform, (iii) Demolding of the composite part obtained at a temperature lower than the crystallization temperature of the thermoplastic matrix.

[0052] Step i)

[0053] Step i) comprises the fabrication of an elongated, unconsolidated textile preform using textile ribbons, more particularly thermoplastic composite ribbons. Step i) is carried out using a specific device described in Figures 1 to 7.

[0054] For the purposes of this invention, a ribbon is said to be textile and therefore comprises fibers, for example unidirectional carbon fibers; these are then dry fibers. A ribbon compatible with the invention is capable of wrapping around the guide and comprises a structure sufficiently rigid to remain wrapped around the guide.

[0055] [Thermoplastic composite ribbons]

[0056] By "thermoplastic composite ribbon", we mean a ribbon comprising fibers of an inorganic or natural material and a thermoplastic polymer composition, capable of melting under the effect of temperature and then solidifying, and thus consolidating the preform.

[0057] In particular, the thermoplastic composite ribbons implemented in step i) may include: reinforcing fibers, continuous or discontinuous, of an inorganic or natural material; and a composition of thermoplastic polymers.

[0058] In some embodiments, the thermoplastic composite ribbons comprise fibers of inorganic or natural materials: impregnated with a composition of thermoplastic polymers (commonly called "tape"); or or pre-impregnated with a composition of thermoplastic polymers, particularly in powder form, or mixed with thermoplastic polymer fiber(s), and commonly called "co-mixed ribbons".

[0059] In preferred embodiments, the thermoplastic composite tape is a tape impregnated with a composition of thermoplastic polymers.

[0060] In embodiments, the thermoplastic composite tape comprises continuous fibers impregnated by a composition based on a thermoplastic polymer plastic, having a glass transition temperature (Tg), measured according to ISO 11357-3:2013, greater than 80°C, preferably greater than or equal to 100°C, even more preferably greater than 120°C, and a melting temperature greater than 150°C when the polymer is semi-crystalline.

[0061] Preferably, the thermoplastic polymer composition of the composite tape comprises predominantly at least one thermoplastic polymer selected from: polyaryl ether ketones (PAEK), in particular poly(ether ether ketone) (PEEK); polyaryl ether ketone ketone (PAEKK), in particular poly(ether ketone ketone) (PEKK); polyaryl sulfones; polyaryl sulfides, in particular polyphenylene sulfides (PPS); polyamides (PA); PEBA; polyolefins, in particular polypropylene, polylactic acid (PLA), polyvinyl alcohol (PVA); and fluoropolymers, in particular polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE) or polychlorotrifluoroethylene (PCTFE); and mixtures thereof.

[0062] Advantageously, said at least thermoplastic polymer is selected from polyamides, PEKK, PEI and a mixture of PEKK and PEI.

[0063] In embodiments, the thermoplastic polymer composition of the composite tape mainly comprises a polyamide, preferably semi-crystalline.

[0064] In some embodiments, the polyamide is an aliphatic, cycloaliphatic or semi-aromatic polyamide.

[0065] The aliphatic polyamide can be selected from PA 5, PA5-10, PA6, PA66, PA6-10, PA6-12, PA6-18, PA9, PA10-10, PA 10-12, PAU, PA12, and their mixture.

[0066] The semi-aromatic polyamide can be chosen from PA MPMDT / 6T, PA 11 / 10T, PA 11 / BACT, PA 5T / 10T, PA 11 / 6T / 10T, PA MXDT / 4T, PA MXDT / 6T, PA MXDT / 10T, PA MPMDT / 4T, PA MPMDT / 6T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 4T, PA BACT / 10T / 6T, PA 11 / BACT / 4T, PA 11 / BACT / 6T, PA 11 / BACT / 10T, PA 11 / MXDT / 4T, PA 11 / MXDT / 6T, PA 11 / MXDT / 10T, PA 11 / MPMDT / 4T, PA 11 / MPMDT / 6T, PA 11 / MPMDT / 10T, PA 11 / MXDT / 10T, PA11 / 5T / 10T, and their mixtures.

[0067] The fibers of the composite ribbons can be chosen from glass fibers, carbon fibers, basalt fibers, or are basalt-based. The fibers of the composite ribbons can also be natural fibers such as flax fibers, reinforcements, or bamboo fibers, or hemp or cellulose fibers.

[0068] When the reinforcement is made of natural fibers or bamboo reinforcement, the thermoplastic resin shall be semi-crystalline with a melting point below 250°C, preferably 220°C, even more preferably 200°C.

[0069] The fibers of thermoplastic composite ribbons are preferably unidirectional, meaning that in this case the fibers are all oriented in the same direction, i.e., along the length of the ribbon. The ribbons can also be composed of several layers of fibers superimposed on each other and having different orientations from one layer to another: however, even in this case, the fibers are non-woven and / or non-braided.

[0070] In embodiments, the composite ribbons contain a fiber content of between 40 and 70% by volume, preferably between 50 and 60% by volume of the material constituting the composite ribbons. This fiber percentage can be determined according to well-known methods such as those described in ISO 14127:2008.

[0071] In embodiments, the selected ribbons (10) further include non-composite thermoplastic polymer ribbons (10).

[0072] In other embodiments, the non-composite thermoplastic polymer ribbons (10) represent a minor mass fraction of the preform compared to the mass fraction of the thermoplastic composite ribbons.

[0073] In yet other embodiments, the polymer composition constituting the non-composite thermoplastic ribbons (10) comprises mainly a polyamide, preferably semi-crystalline.

[0074] In variants of the embodiments, the ribbons (10) have a thickness between 50 and 300 pm, in particular between 50 and 260 pm and more particularly between 60 pm and 170 pm.

[0075] In variants of the embodiments, the ribbons (10) have a width between 5 mm and 50 mm, in particular between 10 mm and 15 mm.

[0076] The ribbons are laid towards the guide with a winding angle strictly greater than -90° relative to the X direction of advancement of the textile element and strictly less than 90° relative to the X direction of advancement of the textile element. Each layer may have a different orientation.

[0077] In other words, the winding angle of the ribbon (10) with respect to the direction X is between +90° and -90°, the terminals +90° and -90 not being included.

[0078] In embodiments, the winding angle is equal to + / -54.8° to + / -10°, preferably to + / -5°, better still to + / -1°.

[0079] The preform obtained at the end of step i) has a constant cross-section over its entire length.

[0080] The textile preform obtained at the end of step i) generally comprises several layers, in particular as many layers as there are modules (4) implemented. Each layer is formed by winding a ribbon, which may be of the same or different nature as the ribbon of at least one adjacent layer.

[0081] Thus, non-composite thermoplastic ribbons can, in particular, be sandwiched between two layers of thermoplastic composite ribbon and / or constitute the inner layer of the preform and therefore of the elongated textile element after consolidation. This The inner layer formed by non-composite thermoplastic ribbons can notably play the role of a barrier layer to the fluid contained in the pipe.

[0082] In embodiments, the thermoplastic polymer composition of the thermoplastic composite ribbons (10), on the one hand, and that of the non-thermoplastic composite polymer ribbons (10), on the other hand, are compatible, in particular totally or partially miscible and are in particular identical.

[0083] The total or partial compatibility of said compositions allowing their welding is defined by the ratio composed of:

[0084] - the difference in glass transition temperatures of the two compositions present in the interfacial layer created by the weld,

[0085] - related to the difference in glass transition temperatures of the two com positions, before the welding of these two compositions.

[0086] Compatibility is total when said ratio is equal to 0, and compatibility is partial when said ratio is not equal to 0 but less than 1, in absolute value. Total incompatibility of the polyamide included in the composition constituting the sealing layer with the polyamide included in the composition that impregnates the fibrous material of the intermediate layer is excluded. Similarly, total incompatibility of the polyamide included in the composition that impregnates the fibrous material of the intermediate layer with the polyamide in the composition that impregnates the fibrous material of the outer layer is excluded.

[0087] Advantageously, when the compatibility of said compositions is partial, said ratio is less than 30%, preferably less than 20%, in absolute value.

[0088] In embodiments, the glass transition temperature(s) of the mixture, depending on whether the compatibility is total or partial, must be between the glass transition temperatures of said polyamides before mixing and different from them, by at least 5°C, preferably by at least 10°C.

[0089] The expression "fully compatible" means that when, for example, two polyamides denoted PAa and Pab, having respectively a Tga and a Tgb, are present respectively in two sealing layers or two adjacent reinforcement layers, and Tga is less than Tgb, then the mixture of the two polyamides has only one Tgab, the value of which is between Tga and a Tgb.

[0090] Advantageously, when the compatibility of said compositions is partial, said ratio is less than 30%, preferably less than 20%, in absolute value.

[0091] In embodiments, the glass transition temperature(s) of the mixture, depending on whether the compatibility is total or partial, must be between the glass transition temperatures of said polyamides before mixing and different from them, by at least 5°C, preferably by at least 10°C.

[0092] The expression "fully compatible" means that when, for example, two po Lyamides denoted Paa and Pab, having respectively a Tga and a Tgb, are present respectively in two adjacent layers, and if Tga is less than Tgb, then the mixture of the two polyamides has only one Tgab, the value of which is between Tga and one Tgb.

[0093] This value Tgab is then greater than Tga by at least 5°C, in particular by at least 10°C and less than Tgb by at least 5°C, in particular by at least 10°C.

[0094] The expression "partially compatible" means that when, for example, two polyamides Paa and Pab, having respectively a Tga and a Tgb, are present respectively in two sealing layers or two adjacent reinforcement layers, then the mixture of the two polyamides has two Tgs: Tg'a and Tg'b, with Tga < Tg'a < Tg'b < Tgb.

[0095] These values ​​Tg'a and Tg'b are then greater than Tga by at least 5°C, in particular by at least 10°C and less than Tgb by at least 5°C, in particular by at least 10°C.

[0096] An incompatibility of two polyamides results in the presence of two Tg, Tga and Tgb, in the mixture of the two polyamides which correspond to the respective Tg Tga and Tgb of the pure polymers taken separately.

[0097] We would not depart from the invention if the glass transition temperatures in the mixture of the two polyamides were identical or different from the temperatures before mixing, but that these two polyamides were reactive with each other.

[0098] According to other embodiments, the preform may comprise several layers of thermoplastic composite ribbons, the thermoplastic polymer being of the same or different nature as the thermoplastic polymer of the adjacent layer.

[0099] The preform may comprise up to 50 layers, in particular 47 layers. It may, in particular, comprise 10 layers of non-composite thermoplastic ribbons and 37 layers of thermoplastic composite ribbons. In some embodiments, the preform comprises 10 internal layers of non-composite thermoplastic ribbons, forming a sealing layer after consolidation, and 10 to 50 layers of thermoplastic composite ribbons, in particular 37 layers of thermoplastic composite ribbon, especially through-impregnated ribbons forming a reinforcing layer.

[0100] According to one feature of the invention, each module of the preform manufacturing device comprises independent feeding means. Thus, each module can dispense ribbons of a different type. The type and dimensions of the ribbons can vary from one layer to another.

[0101] The main longitudinal guide comprises a circular section. The resulting elongated element has the shape of a tube.

[0102] According to yet another feature of the invention, the feeding means comprise at least one ribbon distributor disposed around the crown feed. The implementation of a ribbon distributor allows for easy storage and distribution of ribbons to the main guide, with the distributor(s) rotating around the guide according to the rotation speed of the feed ring.

[0103] According to one embodiment of the invention, the ribbon distributors include pivoting means on the feed ring. The implementation of these pivoting means allows the ribbon distribution to be oriented towards the guide, thus enabling the selection of an angle between -90° and 90° between the ribbon and the guide. All ribbons of the same module have substantially the same angle with the guide.

[0104] According to another embodiment of the invention, the ribbon distributors comprise at least one guillotine capable of cutting at least one ribbon exiting a distributor and a motorized element capable of bringing the ribbon towards the guide.

[0105] According to another embodiment of the invention, the tape dispensers include welding means, for example ultrasonic welding means, suitable for welding a tape to an existing or top layer. Other welding means compatible with the nature of the tapes used are possible within the scope of the invention. It may be advantageous to add or remove one or more tapes, which is possible within the scope of the invention through the implementation of the guillotine and / or welding means.

[0106] According to one embodiment of the invention, the device further comprises a draw-aid device suitable for guiding the ribbons of the module(s).

[0107] The use of a draw-aid device facilitates the sliding of the different layers of tape along the main guide. An example of a draw-aid device is a system of at least one roller arranged downstream of the last module in the X direction. This roller or these rollers exert sufficient pressure to cause the layers of tape to slide along the main guide.

[0108] Depending on the nature of the ribbons, this aid device can be removed during the manufacture of the textile element, which, due to its rigidity, can advance on its own along the guide. In other embodiments, the nature of the ribbons does not require any drawing aid.

[0109] The feed speed V1 corresponds to the feed speed of the textile element on the main guide. The feed speed VI is therefore substantially the same for each of the modules. The feed speed VI and the rotation speed V2 of each module are linked, on the one hand, to the angle defined between the ribbon(s) fed by each of the modules and their feed speed.

[0110] According to one embodiment of the invention, the process further comprises a step of storing the elongated element wound around a storage reel. The process according to the invention makes it possible to manufacture, until the ribbon supply is exhausted, a large elongated element, for example, up to a kilometer in length. The elongated element is stored on a reel at the output of the The device facilitates handling.

[0111] According to one embodiment of the invention, the method further comprises the step of assisting in the drawing of the ribbons with the implementation of the drawing aid device. The drawing aid device is placed downstream of the last module delivering the last layer of the textile element. An operator can, for example, guide each of the ribbon layers towards the drawing aid device, which will then help to slide the different layers onto the main guide.

[0112] According to one embodiment of the invention, the storage reel is a device for assisting in drawing the ribbons from the means of feeding the modules of the manufacturing device.

[0113] According to one embodiment of the invention, the process further comprises a bending step. This step is preferably carried out at room temperature on the elongated element obtained at a desired angle. An advantage of the manufacturing device is the possibility of bending the elongated element at room temperature.

[0114] For the purposes of this description, "room temperature" means a temperature between 15 and 25 °C.

[0115] Preferably, the absence of smearing on the thermoplastic composite ribbons composing the preform also contributes to improving the mechanical performance of the composite reinforcement. Indeed, smearing induces local overstress at the points where the fibers cross each other and therefore constitutes a weak point mechanically. Furthermore, the absence of smearing at the time of deposition results in a smaller quantity of air (and therefore fewer defects) to be removed during consolidation. This reduces cycle times and the energy consumed for consolidation, as well as the residual porosity.

[0116] Step ii)

[0117] The elongated textile preform obtained in step i) is then co-consolidated in a mold with at least one part fitting into the textile preform.

[0118] This co-consolidation step includes a heating step in a closed mold at a temperature above the melting temperature of the thermoplastic matrix and under pressure, the mold imposing a change of shape on the preform, followed by a cooling step within the mold of the consolidated preform.

[0119] The heating step is carried out at a temperature above the melting temperature of the thermoplastic matrix, preferably between a temperature equal to the melting temperature of the thermoplastic matrix + 5°C and the melting temperature of the thermoplastic matrix + 80°C, more particularly between a temperature equal to the melting temperature of the thermoplastic matrix + 10°C and the melting temperature of the thermoplastic matrix + 60°C.

[0120] The heating step is carried out under pressure, preferably under pressure between 1 bar and 25 bars, especially between 5 bars and 10 bars, particularly between 6 bars and 8 bars.

[0121] This heating step allows the different layers of ribbons constituting the preform to be welded together. The heating temperature is therefore determined according to the nature of the ribbons (10) chosen.

[0122] Thus, two or more parts are placed in the mold. These parts have different diameters so that they can fit one inside the other or one inside the other.

[0123] In the context of this invention, "to fit together" means to assemble or to be fitted together. The textile preform, for example, cylindrical in shape, will conform to a part that is also cylindrical, but with a diameter, for example, substantially larger, so that the surfaces of each part are in contact with each other. For example, the inner surface of the preform may be in contact with the outer surface of the ring, or the inner surface of the ring may be in contact with the outer surface of the preform.

[0124] Coconsolidation allows the polymer matrices of the parts to fuse together and thus adhere to each other.

[0125] Preferably, the consolidation step uses a bladder placed in the preform and applying internal pressure to the preform. Thus, pressure is applied internally by means of a bladder.

[0126] Thus, during the melting of the thermoplastic matrix, the preform will conform to the shape of the mold. This softened preform will be sandwiched between the mold wall and the bladder.

[0127] When pressure is applied by means of an internal bladder to the preform, the ribbons of the preform preferably come to rest against the internal wall of the fitted part, which in particular allows for good consolidation of the preform and also improves the weld, and therefore the mechanical resistance, between the preform and the fitted part.

[0128] Applying these pressures to the softened preform reduces the porosity of the material. Preferably, the final composite part has a residual porosity <10%, preferably <5%, preferably <2%, measured for example by image analysis or by acid digestion or carbonization according to ASTM D3171-15.

[0129] Then, a cooling step is carried out in the mold, still under pressure. This cooling step allows the composite part to solidify. It is therefore essential that it be carried out in the closed mold so as to maintain pressure on the preform.

[0130] Preferably, consolidation step ii) is carried out under internal nitrogen pressure, which further reduces, or even completely eliminates, the risk of thermo-oxidation of the thermoplastic matrix.

[0131] Preferably, step ii) of consolidation is carried out after vacuuming the mold and the preform, before pressurizing the bladder, which further reduces, or even completely eliminates, the risk of thermo-oxidation of the thermoplastic matrix.

[0132] Thus, step i) allows obtaining a preform and step ii) allows co-consolidation of this preform with one or more other parts, such as rings, connectors, fittings, or any other part.

[0133] The consolidation step including heating and then cooling can be a few minutes, i.e. 3 minutes or on the contrary can be slow, i.e. on the order of Ih using low energy-intensive cooling.

[0134] When the mold has low-cost heating and cooling technology, the pressure applied during consolidation can be limited to less than 10 bars, preferably less than 8 bars.

[0135] According to a particular embodiment, several molds can be used in parallel, making it possible to considerably limit the cycle time of manufacturing the complete parts, compared to the cycle time of conventional filament winding or thermoplastic composite ribbon winding processes.

[0136] In a preferred embodiment, and with the aim of further reducing cycle times and energy consumption, the mold used to consolidate the composite preform can be coupled to a molten polymer injection process to either finalize the part (edge ​​finishing or netshape) or to locally overmold features specific to the consolidated part (for example, reinforced plastic sleeves to assemble the tubes a posteriori together or with other composite parts).

[0137] Step iii)

[0138] The process includes a demolding step. The demolding of the composite part is carried out at a temperature lower than the crystallization temperature of the thermoplastic matrix, preferably between ambient temperature and the crystallization temperature, more favorably between the crystallization temperature and the glass transition temperature, and more particularly between the glass transition temperature and the glass transition temperature + 40°C.

[0139] If demolding is carried out at a temperature above Te + 20°C, there is a risk of deformation and weakening of the part.

[0140] Thus, the resulting composite part exhibits very good mechanical strength, superior to that obtained with wet filament winding or conventional thermoplastic composite ribbon winding processes. Indeed, these processes do not offer the possibility of applying high pressure for a long time, particularly when the matrix is ​​hot, i.e., during the phase of the process during which the effects of compaction are most effective (i.e. > one minute).

[0141] Furthermore, in the case of slow cooling and the use of a semi-crystalline thermoplastic resin as the composite matrix, the crystallization of the resin will be optimal, which will improve the mechanical and chemical resistance quality of the resulting composite.

[0142] When the mold has a rapid heating and cooling system, the total cycle time for manufacturing the part: cycle time for manufacturing the preform, then consolidation in the closed mold, then demolding, is much shorter than the cycle time of current processes, such as wet filament winding or winding of thermoplastic composite tapes.

[0143] In a preferred manufacturing method, several tubular preforms can be consolidated and assembled in the same mold to create composite parts with complex geometries. The parts can be partially or totally nested within each other, or juxtaposed for local assembly. The assembly can be achieved by co-consolidation within the mold of the tubular preform(s) with a metal or thermoplastic part, possibly filled, obtained by injection molding, or with a complex-shaped textile preform obtained using TFP technology. Hollow body made of composite material

[0144] According to another aspect, the invention relates to a hollow body made of composite material that can be obtained according to the process as defined above.

[0145] The hollow body is characterized by a complex shape comprising at least two diameters of different sizes. Indeed, the hollow body consists of the preform obtained in step i), which has a certain diameter and the fitted part, which has a necessarily different diameter, because this part enabled the fitting.

[0146] In general, the hollow body can be any element of a complex structure, regardless of the field of activity.

[0147] In the industrial field, the hollow body can be an element of any structure, which requires a very specific design and must exhibit a certain mechanical resistance.

[0148] The hollow body according to the invention can, for example, be a pipe for the transport of fluid, which may incorporate a fitting with a change of orientation, such as an elbow or a change of diameter allowing, for example, a connection with another element of a fluid circulation circuit.

[0149] Preferably, the fluid is not hydrogen.

[0150] In the field of sports, the hollow body can be, for example, the composite part can be a tennis racket, squash racket, padel racket, badminton racket, a trail running pole, A ski pole, a ski lift pole, a hockey stick, a rowing component (rowing boat, canoe, kayak), a golf club, a component of a bicycle frame. Detailed description of the figures

[0151] A device according to the invention, as illustrated in Figures 1 and 2 and designated as a whole by reference numeral 1, is intended for the manufacture of an elongated, unconsolidated textile element. For this purpose, the device 1 comprises a frame 2 including a main longitudinal guide 3 along a direction X, and at least two modules 4 arranged in series around the guide 3 along the direction X.

[0152] The main longitudinal guide 3 is fixed to the frame 2. According to the illustrated embodiments, the main longitudinal guide 3 comprises a circular section and therefore has a tubular shape. This shape is not limiting to the invention; other shapes of guide 3 are compatible with the invention. The guide 3 is straight and may comprise sections of different shapes such as square, rectangular, quadrilateral, triangular, polygonal, round, oval, or mixed and / or freeform shapes.

[0153] A module 4 of a device 1 according to the invention comprises, on the one hand, a feed ring 5 surrounding a section of the main longitudinal guide 3. According to the illustrated examples, the feed ring 5 is substantially in the shape of a disc comprising a central hole in which the guide 3 is located.

[0154] A module 4 includes, on the other hand, feeding means 6 arranged on the ring 5. According to the embodiment illustrated, the feeding means 6 are located on one face of the disk and supply at least one ribbon 10 to the guide 3 with an angle with respect to the X direction between -90° and 90°.

[0155] A ribbon 10 compatible with the invention is, on the one hand, sufficiently flexible to wrap around the guide 3.

[0156] The feeding means 6 arranged on the ring 5 feed at least one ribbon 10 towards the guide 3 with a chosen angle between -90° and 90° with respect to the X direction. Each ribbon 10 winds at least around the guide 3 or on the layer of ribbon 10 already present, i.e. the top layer with an overall feed speed VI chosen.

[0157] Each module 4 also includes drive means 15 for the ring 5. According to [Fig. 2] and also visible in [Fig. 3], the drive means 15 are located on the face of the ring 5 opposite the power supply means 6. The drive means 15 for the ring 5 allow the ring 5 to rotate around the guide 3 at a rotational speed V2. According to the illustrated embodiment, the drive means 15 include a motor comprising, in particular, a belt adapted to rotate the ring 5 and a motor control unit to implement a rotational speed V2 of the ring 5. This configuration is not limiting to the invention.

[0158] The device illustrated in Figures 1 and 2 comprises two modules 4. The feeding means 6 of the first module 4 comprise two ribbon dispensers 20, and the feeding means 6 of the second module 4 comprise a single ribbon dispenser 20. The feeding means 6 of the different modules 4 are independent of each other. Thus, each module 4 can deliver ribbons 10 of a different type and a chosen number of ribbons 10 per layer.

[0159] Figure 4 illustrates a module 4 comprising six ribbon dispensers 20 of 10. The dispensers Distributors 20 of ribbon 10 are arranged around the feed ring 5. According to the illustrated embodiments, a distributor 20 of ribbon 10 comprises a reel 21 fixed on one face of the ring 5 with pivoting means 22.

[0160] According to this illustrated but non-limiting embodiment, the pivoting means 22 comprise a fixed part 23 and a pivoting part 24 directed towards the coil 21. The coil 21 is free to pivot in the pivoting part 24 and the pivoting part is free to pivot relative to the fixed part 23. Thus, the coil 21 can be arranged in a desired configuration and the pivoting means 22 can be locked according to the desired arrangement of the distributor 20.

[0161] Figure 5 illustrates a particular embodiment of the invention in which a ribbon dispenser 20 also comprises a guillotine 25 for cutting the ribbon 10 at the outlet of the dispenser 20, a motor M for feeding the ribbon after cutting, and ultrasonic welding means 26 for welding a ribbon 10 to an existing layer of ribbons 10 or an upper layer. The illustration of the motor M, the guillotine 25, and the welding means 26 is schematic in Figure 5, and other embodiments are possible, particularly with means for acting on a ribbon 10 outside the dispenser 20.

[0162] Figures 6 and 7 illustrate a particular embodiment of the invention. The device 1 comprises three modules 4. The first module 4 comprises four ribbon 10 dispensers 20, each depositing a ribbon 10 in the direction of travel X, i.e., the angle between the ribbon 10 and the guide 3 is 0 degrees. The second module 4 comprises two ribbon 10 dispensers 20, and the third module 4 comprises a single ribbon 10 dispenser 20. This embodiment is not limiting to the invention.

[0163] In order to manufacture an elongated element 11 according to the invention, a first step consists of implementing feeding means 6 on each of the modules 4 of the device 1. For this purpose, according to the illustrated examples, reels 21 each comprising a selected ribbon 10 are arranged on each feeding ring 5 of the device 1.

[0164] Preferably, the reels deliver the same 10 ribbon per module and each module 4 can include reels of 10 ribbon of different types.

[0165] According to the example illustrated in figures 6 and 7, the ribbons 10 used have a width between 20 and 10 mm and a thickness of about 150 microns.

[0166] A second step of the process consists of setting, on the one hand, the feed speed VI and, on the other hand, the rotation speed V2 of each of the modules 4. The precise and coordinated setting of these two values ​​makes it possible to define, for each feeding means 6, a desired angle between the ribbon 10 and the guide; this angle varies between -90° and 90°, excluding these two interval limits. For example, and according to the device illustrated in Figures 6 and 7, a first layer of ribbon 10 is deposited at an angle close to 0° with respect to the X direction, a second layer of ribbon 10 is deposited at an angle of approximately 80° with respect to the X direction, and a third layer is deposited at an angle close to -80° with respect to the X direction.

[0167] An example of parameterization consists of defining a forward speed VI approximately equal to one meter per minute and a rotation speed V2 of two modules 4, each distributing a ribbon 10, approximately equal to 360 revolutions per minute. This example is not limiting to the invention.

[0168] Modules 4 are then started up.

[0169] Depending on the nature of the ribbons 10, a drawing aid device 30 is implemented to assist in drawing the ribbons 10 from the different layers of the element 11. According to the embodiment illustrated in Figures 6 and 7, the first layer of ribbon 10 from the first module 4 slides on the main guide 3 through the two other modules 4. The ribbons 10 of the first layer can slide on their own if their nature allows, or with manual assistance. The ribbons 10 of the other layers are deposited on the previous layer and then pass through the drawing aid device 30. This aid device 30 is not always necessary for the implementation of the process, but it can assist the sliding of the different layers in the X direction, depending on the nature of the ribbons 10 used.

[0170] According to a particular embodiment with, in particular, ribbons of the first layer arranged at an angle close to 0° with the X direction, there is not necessarily a need for manual assistance to advance said ribbons 10.

[0171] According to another embodiment, once further layers of tape 10 are superimposed on the first layer, the elongated element 11 is formed without assistance, and the draw-aid device 30 is no longer needed and can be removed. This may be a transitional start-up assistance period necessary if the nature of the tape 10 used does not allow the tape to unwind efficiently from its reel 21.

[0172] The elongated element 11 being manufactured can be stored wound around a storage reel, thus facilitating its subsequent handling. The elongated element 11 can also be cut as it is manufactured to the desired size and according to the additional steps described below, for example, increasing or of size reduction.

[0173] According to one embodiment (not illustrated) the storage reel is a device

[0174] for assisting in the pulling of the ribbons 10. Indeed, during its winding, the textile element 11 causes the pulling of the ribbons 10 which form it.

[0175] When the elongated element 11 is of the desired size, it can then be cut. Another way to complete the process is to wait until the ribbons 10 are exhausted.

[0176] The resulting unconsolidated, elongated textile element 11 can then be recovered. Consolidation steps can then be applied to it, for example, a thermoforming step when the dimensions allow. During the consolidation of the elongated element 11, it is also possible to slightly vary its dimensions, particularly its perimeter, by approximately 10-20%.

[0177] According to a particular embodiment, a secondary longitudinal guide (not shown) is positioned at the first module 4 during manufacturing. This secondary guide, with a diameter or cross-section larger than the diameter or cross-section of the main guide 3, is placed upstream of the first module 4 and translates in the manufacturing direction of the elongated element 11. The strips 10 of the various modules 4 are then deposited onto the secondary guide, and again onto the main guide 3 after passing over the secondary guide. It is thus also possible to significantly increase the diameter, cross-section, or overall shape of the elongated element 11 during its manufacturing.

[0178] Fig. 8 is a front view of an elongated, unconsolidated textile preform 40. Fig. 9 is a perspective view of the elongated, unconsolidated textile preform 40.

[0179] Fig. 10 represents the elongated, unconsolidated textile preform 40 positioned in a mold 41 and fitted into rings 42 at each end.

[0180] Fig. 11 represents the final hollow body in composite material, i.e. the part co-consolidated with the rings at its ends.

[0181] Fig. 12 is a perspective view of an elongated, unconsolidated, curved textile preform 44. This preform is obtained following manufacturing step i) and after a bending step.

[0182] Fig. 13 is a cross-sectional view of the hollow body 45 in the final composite material, i.e. the part co-consolidated with the rings at its ends. This hollow body is curved.

[0183] Of course, various other modifications can be made to the invention within the scope of the annexed claims.

Claims

Demands

1. A method for manufacturing a hollow body made of composite material, said method comprising the following successive steps: (i) Manufacture of an elongated, unconsolidated textile preform by means of a device (1) comprising: - a frame (2) comprising a main longitudinal guide (3) along a direction X, said guide (3) being fixed on the frame (2) and - at least two modules (4) arranged in series around the guide (3) along the X direction, each module (4) comprising: - a feed ring (5) surrounding a section of the guide (3), - feed means (6) arranged on the ring (5) capable of feeding at least one tape (10) towards the guide (3) at a winding angle between -90° and 90° with the direction X and at a forward speed VI, each tape (10) being capable of winding at least around the guide (3) or over the upper layer of tape (10), and - drive means (15) for the ring (5) capable of rotating the ring (5) around the guide (3) at a rotational speed V2, The said preform is manufactured according to a process comprising the steps of: - Implementation of the power supply means (6) on each of the modules (4), said power supply means (6) comprising selected ribbons (10), said selected ribbons (10) comprising at least thermoplastic composite ribbons - Setting the forward speed VI and the rotation speed V2 of each of the modules (4) and starting up each module (4), - Cutting of the elongated element (11) and / or exhaustion of the ribbons (10), and - Recovery of the elongated unconsolidated textile preform (11) obtained; the elongated, unconsolidated textile preform having a constant cross-section along its entire length, (ii) Co-consolidation in a mold (41) of the textile preform obtained in the previous step (40) with at least one part (42) fitting into the textile preform (40), (iii) Demolding of the composite part obtained at a temperature lower than the crystallization temperature of the thermoplastic matrix.

2. A method according to claim 1, wherein the heating step of step ii) is carried out at a temperature between a temperature equal to the melting temperature of the thermoplastic matrix + 5°C and the melting temperature of the thermoplastic matrix + 80°C, more particularly between a temperature equal to the melting temperature of the thermoplastic matrix + 10°C and the melting temperature of the thermoplastic matrix + 60°C.

3. A method according to claim 1 or 2, wherein the heating step of step ii) is carried out at a pressure between 0.5 bar and 50 bar, in particular between 0.5 bar and 10 bar, in particular between 0.5 bar and 7 bar, in particular between 1 and 7 bar.

4. A method according to any one of the preceding claims, wherein a bending step is carried out before the consolidation step ii'»

5. n j. A method according to any one of the preceding claims, wherein the thermoplastic composite tapes comprise: - Reinforcing fibers, continuous or discontinuous, of an inorganic or natural material; and - A composition of thermoplastic polymers.

6. A method according to any one of the preceding claims, wherein the reinforcing fibers of an inorganic or natural material are: - impregnated or pre-impregnated with a composition of thermoplastic polymers, or - mixed with fibers of thermoplastic polymer(s).

7. A method according to any one of the preceding claims, wherein the thermoplastic polymer composition of the composite tape predominantly comprises at least one thermoplastic polymer selected from: polyaryl ether ketones (PAEK), in particular poly(ether ether ketone) (PEEK); polyaryl ether ketone ketone (PAEKK), in particular poly(ether ketone ketone) (PEKK); polyaryl sulfones; polyaryl sulfides, in particular polyphenylene sulfides (PPS); polyamides (PA); PEBA, polyolefins, in particular polypropylene, polylactic acid (PLA), polyvinyl alcohol (PVA), and fluorinated polymers, in particular polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE) or polychlorotrifluoroethylene (PCTFE); and mixtures thereof, preferably, the thermoplastic polymer composition of the composite tape comprises predominantly a polyamide, preferably semi-crystalline.

8. A method according to claim 7, wherein the thermoplastic polymer is an aliphatic, cycloaliphatic or semi-aromatic polyamide.

9. A method according to claim 8, wherein the aliphatic polyamide is selected from PA 5, PA5-10, PA6, PA66, PA6-10, PA6-12, PA6-18, PA9, PA10-10, PA 10-12, PAU, PA12, and mixtures thereof, and the semi-aromatic polyamide is selected from PA MPMDT / 6T, PA 11 / 6T, PA 11 / 10T, PA 11 / BACT, PA 5T / 10T, PA 11 / 6T / 10T, PA MXDT / 4T, PA MXDT / 6T, PA MXDT / 10T, PA MPMDT / 4T, PA MPMDT / 6T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 4T, PA BACT / 10T / 6T, PA 11 / BACT / 4T, PA 11 / BACT / 6T, PA 11 / BACT / 10T, PA 11 / MXDT / 4T, PA 11 / MXDT / 6T, PA 11 / MXDT / 10T, PA 11 / MPMDT / 4T, PA 11 / MPMDT / 6T, PA 11 / MPMDT / 10T, PA 11 / MXDT / 10T, PA11 / 5T / 10T, and their mixture.

10. A method according to any one of the preceding claims, wherein the fibers of the thermoplastic composite tapes are selected from glass fibers, carbon fibers, basalt or basalt-based fibers, or are natural fibers such as flax fibers, reinforcements or bamboo fibers or hemp or cellulose fibers.

11. A method according to any one of the preceding claims, wherein the fibers of the thermoplastic composite tapes are unidirectional, i.e. all oriented along the length of the tape.

12. A method according to any one of the preceding claims, wherein the composite ribbons contain a fiber content of between 40 and 70% by volume, preferably between 50 and 60% by volume of the thermoplastic composite ribbons.

13. A method according to any one of the preceding claims, wherein the selected ribbons (10) further comprise non-composite thermoplastic polymer ribbons (10).

14. A method according to claim 13, wherein the ribbons (10) of Non-composite thermoplastic polymers represent a minority mass fraction of the preform compared to the mass fraction of thermoplastic composite tapes.

15. A method according to claim 14, wherein the polymer composition constituting the non-composite thermoplastic ribbons (10) comprises predominantly a polyamide, preferably semi-crystalline.

16. A method according to claim 15, wherein the thermoplastic polymer composition of the thermoplastic composite ribbons (10) on the one hand, and that of the non-composite thermoplastic polymer ribbons (10) on the other hand, are compatible, in particular identical.

17. A method according to any one of the preceding claims, wherein the ribbons (10) have a thickness between 50 and 300 pm, in particular between 50 and 260 pm and more particularly between 60 pm and 170 pm.

18. A method according to any one of the preceding claims, wherein the ribbons (10) have a width between 5 mm and 50 mm, in particular between 10 mm and 15 mm.

19. A method according to any one of the preceding claims, wherein the winding angle of the ribbon (10) with respect to the X direction is between +90° and -90°.

20. A method according to any one of the preceding claims, wherein in step ii) pressure is applied by means of an internal bladder to the preform.

21. Hollow body made of composite material that can be obtained according to the process as defined in claims 1 to 20.

22. Use of the composite hollow body as defined in claim 21, as a conduit for the transport of fluid.

23. Use of the composite hollow body as defined in claim 21, as an element of a sporting article, preferably a bicycle frame, a racquet frame, a ski pole, a hiking pole, a hockey stick, a golf club, a rowing element (rowing, canoeing, kayaking).

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