Manufacturing process for a hollow body made of composite material of variable 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 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 the composite part obtained at a temperature below the crystallization temperature of the thermoplastic matrix, as well as on the hollow body. Figure for abstract: Fig. 10

Description

Title of the invention: Method for manufacturing a hollow body made of composite material of variable section Field of 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 conventionally 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 of the AFP or filament winding type, which make it possible to produce composite parts either directly from raw materials mixed in line (fiber and resin), or from semi-finished products. The semi-finished products usable in AFP and filament winding, comprising thermoplastic resins, can be thermoplastic prepregs.

[0003] Other innovative technologies make it possible to produce composite parts from prepregs (thermoplastic or thermosetting), most of which are inspired by the textile industries. 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 having an axis of revolution, existing industrially such as wet filament winding, by winding thermoplastic composite ribbons for example, are generally slow; either because of the long time required for the deposition of the prepregs; or (or in addition) because of the polymerization times (cooking) required for the polymerization of thermosetting resins for example.

[0005] Furthermore, the heating processes are generally not optimized, neither technically (LASER which tends to overheat thermoplastic composites for example), nor economically (cooking time of several hours for thermoset composites in an 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 porosities, linked to the low pressure applied during the implementation of the fibers pre-impregnated with resin, when it comes to wet impregnation or during the in situ consolidation of the thermoplastic composite ribbons.

[0007] In addition, and this is mainly the case for manual removal processes but also With robotic processes, there can be a significant loss of raw material during manufacturing. For example, there are minimum dimensions that can be deposited using the AFP or filament winding process. There are also significant minimum lengths required (several meters or even tens of meters / reel) to reach the depositing head from the reel (or creel), 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 either because of the excessive bulk of the processing equipment (dimensions of the AFP deposition head for example) or because of the deposition angles which are physically not achievable without over-consuming material in the external zones of the tubular parts.

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

[0010] The problem to be solved is to find an efficient manufacturing process, both technically (in particular in terms of mechanical performance) and economically (manufacturing cycle time, losses of materials or energy linked to the manufacturing or assembly process, etc.), to manufacture assembled parts with improved mechanical strength. These parts thus manufactured are 3D objects optimized in their design and performance as well as from an economic point of view.

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

[0012] For the purposes of the present invention, complex geometry means a part which can have different angles, and / or at least one non-planar surface, and / or variations in the internal distances of the 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 the consolidation in a closed mold (either quickly or in parallel with several molds).

[0014] Another advantage of the process is that it is possible 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] Consequently, a simple, rapid and inexpensive process is currently being sought which makes it possible to obtain composite parts of complex shape which have good mechanical strength, in particular at high temperature, and which are recyclable.

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

[0017] This problem is solved by the method 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 embedding, said preform being capable of being obtained from a specific device, shown in [Fig.l]; the elongated and unconsolidated textile preform having a constant 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 part fitting into the textile preform, - A third demolding step 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 rapid and inexpensive access to textile preforms of large dimensions, in particular of small diameter with great lengths.

[0020] Furthermore, step i) of the method according to the invention makes it possible to superimpose a very large number of layers: the preform can contain as many desired layers of tape as there are modules implemented.

[0021] The device implemented in step i) uses guides to deploy the ribbons in the same direction. It thus makes it possible to produce elongated textile preforms of cylindrical shape. The preform can be easily bent at room temperature in order to give it a particular non-rectilinear shape which is then fixed during the consolidation step ii). This will however require a particular choice of the 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 ribbons of the textile preform, making it possible to adapt the composite part obtained to other elements. In addition, This co-consolidation makes it possible to improve the mechanical resistance and / or cohesion between the insert and the co-consolidated composite part.

[0023] The method includes a step iii) of demolding, which must be carried out at a specific temperature so as 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 using a device (1) comprising: - a frame (2) comprising a main longitudinal guide (3) in 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) in the X direction, each module (4) comprising: - a feed crown (5) surrounding a section of the guide (3), - feed means (6) arranged on the crown (5) capable of feeding at least one ribbon (10) towards the guide (3) at a winding angle of between -90° and 90° with the direction X and at a feed speed VI, each ribbon (10) being capable of winding at least around the guide (3) or on 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 rotation speed V2, Said preform being manufactured according to a process comprising the steps of: Implementation of the supply means (6) on each of the modules (4), said supply means (6) comprising selected ribbons (10), said selected ribbons (10) comprising at least thermoplastic composite ribbons Setting the feed 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 unconsolidated elongated textile preform (11) obtained; the unconsolidated elongated textile preform having a constant 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 of 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 fibers. 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); PEBAs, polyolefins, in particular polypropylene, polylactic acid (PLA), polyvinyl alcohol (PVA), and fluoropolymers, in particular polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE) or polychlorotrifluoroethylene (PCTFE); and their mixtures, preferably, the thermoplastic polymer composition of the composite tape mainly comprises 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 ribbons are unidirectional, i.e. all oriented along the length of the ribbon. - the composite tapes contain a fiber content of between 40 and 70% by volume, preferably between 50 and 60% by volume of the thermoplastic composite tapes. - the selected ribbons (10) further comprise non-composite ribbons (10) of thermoplastic polymer. - 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) mainly comprises 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 of 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 of between 5 mm and 50 mm, in particular between 10 mm and 15 mm. - the winding angle of the ribbon (10) relative to the X direction is between +90° and - 90°. - step ii) the pressure is applied by means of a bladder internal to the preform.

[0026] According to a second aspect, the invention relates to a hollow body made of composite material capable of being obtained according to the method 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 pipe for transporting 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 component (oar, canoe, kayak).

[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 the composite parts of the state of the art.

[0029] Indeed, unlike conventional methods involving braiding of composite ribbons, the method of the invention preferably allows winding of the ribbons without weaving, which makes it possible to avoid local overstressing at the points where the fibers intersect, and therefore to improve the mechanical strength 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 ribbons do not allow high pressure to be applied, particularly for a prolonged period, so that the quality of the consolidation is often quite low.

[0032] Furthermore, the inventors were able to observe that step ii) of consolidation of the preform under pressure made it possible to give the composite part obtained 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 method according to the invention,

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

[0035] [Fig.3] is a perspective view of an example of a 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 exemplary ribbon feeding means used in step i) of the process according to the invention,

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

[0039] [Fig.7] is a perspective view from an opposite angle of the device of [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 showing the elongated textile and unconsolidated 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 curved,

[0045] [Fig. 13] is a 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) Manufacture of an elongated textile and unconsolidated preform by means of a device (1) comprising: - a frame (2) comprising a main longitudinal guide (3) in 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) in the X direction, each module (4) comprising: - a feed crown (5) surrounding a section of the guide (3), - feed means (6) arranged on the crown (5) capable of feeding at least one ribbon (10) towards the guide (3) at a winding angle of between -90° and 90° with the direction X and at a feed speed VI, each ribbon (10) being capable of winding at least around the guide (3) or on 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 rotation speed V2, Said preform being manufactured according to a process comprising the steps of: Implementation of the supply means (6) on each of the modules (4), said supply means (6) comprising selected ribbons (10), said selected ribbons (10) comprising thermoplastic composite ribbons, Setting the feed 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 unconsolidated elongated textile preform (11) obtained; the elongated, unconsolidated textile preform having a constant 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 manufacture of an elongated textile and unconsolidated preform, using so-called 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 the invention, a ribbon is said to be textile and therefore comprises fibers, for example unidirectional carbon fibers, in which case these are dry fibers. A ribbon compatible with the invention is capable of being wound around the guide and comprises a structure that is sufficiently rigid to remain wound around the guide.

[0055] [Thermoplastic composite ribbons]

[0056] By "thermoplastic composite tape" is meant a tape comprising fibers of an inorganic or natural material and a thermoplastic polymer composition, capable of melting under the effect of temperature then solidifying, and therefore consolidating the preform.

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

[0058] In embodiments, the thermoplastic composite ribbons comprise fibers of inorganic or natural materials: impregnated with a composition of thermoplastic polymers (commonly referred to as “tape”); or or pre-impregnated with a composition of thermoplastic polymers, in particular in powder form, or mixed with thermoplastic polymer fibers, and commonly called “commingled ribbons”.

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

[0060] In embodiments, the thermoplastic composite tape comprises continuous fibers impregnated with a thermoplastic polymer-based composition 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; polyarylsulfides, in particular polyphenylene sulfides (PPS); polyamides (PA); PEBAs; 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 one 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 predominantly comprises a polyamide, preferably semi-crystalline.

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

[0065] The aliphatic polyamide can be 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.

[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 mixture.

[0067] The fibers of the composite ribbons may be chosen from glass fibers, carbon fibers, basalt fibers or are basalt-based. The fibers of the composite ribbons may 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 will be semi-crystalline with a melting point below 250°C, preferably 220°C, even more preferably 200°C.

[0069] The fibers of the thermoplastic composite ribbons are preferably unidirectional, which means 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 presenting 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 percentage of fibers can be determined according to well-known methods such as those described in ISO14127:2008

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

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

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

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

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

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

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

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

[0079] The preform obtained at the end of step i) has a constant 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) used. Each layer is formed by winding a ribbon, which may be of the same or different nature, to that of the ribbon of at least one adjacent layer.

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

[0082] In embodiments, the thermoplastic polymer composition of the thermoplastic composite ribbons (10), on the one hand, and that of the thermoplastic non-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 the glass transition temperatures of the two compositions present in the interfacial layer created by the weld,

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

[0086] Compatibility is total when said ratio is equal to 0, and compatibility is partial when said ratio is different from 0 and less than 1, in absolute value. A total incompatibility of the polyamide included in the composition constituting the sealing layer with the polyamide included in the composition which impregnates the fibrous material of the intermediate layer is excluded. Similarly, a total incompatibility of the polyamide included in the composition which impregnates the fibrous material of the intermediate layer with the polyamide in the composition which impregnates the fibrous material of the external 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 blend, depending on whether the compatibility is total or partial, must be between the glass transition temperatures of said polyamides before blending and different from them, by at least 5°C, preferably by at least 10°C.

[0089] The expression "totally compatible" means that when, for example, two polyamides denoted PAa and Pab respectively having a Tga and a Tgb, are present respectively in two adjacent sealing layers or two reinforcement layers, and that Tga is lower than Tgb, then the mixture of the two polyamides only has a single 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 blend, depending on whether the compatibility is total or partial, must be between the glass transition temperatures of said polyamides before blending 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 polyamides noted Paa and Pab having respectively a Tga and a Tgb, are present respectively in two adjacent layers, and that Tga is lower than Tgb, then the mixture of the two polyamides has only one Tgab, the value of which is between Tga and a Tgb.

[0093] This Tgab value is then higher than Tga by at least 5°C, in particular by at least 10°C, and lower 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 reinforcing layers, then the mixture of the two polyamides has two Tg: Tg'a and Tg'b, with Tga < Tg'a < Tg'b < Tgb.

[0095] These Tg'a and Tg'b values ​​are then higher than Tga by at least 5°C, in particular by at least 10°C, and lower 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 Tgs, Tga and Tgb, in the mixture of the two polyamides which correspond to the respective Tgs Tga and Tgb of the pure polymers taken separately.

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

[0098] According to other embodiments, the preform may comprise several layers of thermoplastic composite tapes, the thermoplastic polymer being able to be 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 tapes, and 37 layers of thermoplastic composite tapes. In embodiments, the preform comprises 10 internal layers of non-composite thermoplastic tapes, forming a sealing layer after consolidation and from 10 to 50 layers of thermoplastic composite tapes, in particular 37 layers of thermoplastic composite tape, in particular impregnated at the core, forming a reinforcing layer.

[0100] According to a characteristic of the invention, each module of the preform manufacturing device comprises independent supply means. Thus, each module can distribute ribbons of a different nature. The nature and dimensions of the ribbons can be different 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 characteristic of the invention, the supply means comprise at least one ribbon dispenser arranged around the crown feed. The implementation of a ribbon dispenser allows for easy storage and distribution of ribbons to the main guide, with the dispenser(s) rotating around the guide according to the rotation speed of the feed ring.

[0103] According to one embodiment of the invention, the ribbon dispensers comprise pivoting means on the feed ring. The implementation of pivoting means makes it possible to orient the distribution of the ribbons towards the guide and thus to choose an angle between -90° and 90° between the ribbon and the guide. All the ribbons of the same module have substantially the same angle with the guide.

[0104] According to another embodiment of the invention, the tape dispensers comprise at least one guillotine capable of cutting at least one tape at the outlet of a dispenser and a motorized element capable of bringing the tape towards the guide.

[0105] According to another embodiment of the invention, the tape dispensers comprise welding means, for example ultrasonic welding means, capable of welding a tape to a present layer or upper 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 thanks to the implementation of the guillotine and / or welding means.

[0106] According to one embodiment of the invention, the device further comprises a pulling assistance device capable of guiding the ribbons of the module(s).

[0107] The use of a pulling aid device makes it easier to slide the different layers of tape along the main guide. An example embodiment of a pulling aid device may be a system of at least one roller arranged downstream of the last module in the X direction. This or these rollers exert sufficient pressure to cause the layers of tape to slide on the main guide.

[0108] Depending on the nature of the ribbons, this assistance device can be removed during the manufacture of the textile element which, due to its rigidity, can advance alone on the guide. According to other embodiments, the nature of the ribbons does not require any pulling assistance.

[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 method further comprises a step of storing the elongated element wound around a storage reel. The method according to the invention makes it possible to manufacture, until the ribbon supply means are exhausted, an elongated element of large size which can be, for example, up to a kilometer. Storing the elongated element on a reel at the outlet of the device facilitates handling.

[0111] According to an alternative embodiment of the invention, the method further comprises the step of assisting in pulling the ribbons with the implementation of the pulling assistance device. The pulling assistance 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 layers of ribbon towards the pulling assistance 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 supply means of the modules of the manufacturing device.

[0113] According to one embodiment of the invention, the method further comprises a bending step. This step is preferably carried out at room temperature of 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] By “room temperature” as used in this description, we mean a temperature between 15 and 25°C.

[0115] Preferably, the absence of fogging of the thermoplastic composite ribbons making up the preform also contributes to improving the mechanical performance of the composite reinforcement. Indeed, fogging induces local over-stress at the points where the fibers cross each other and therefore constitutes a weak point from a mechanical point of view. In addition, the absence of fogging at the time of deposition results in a smaller quantity of air (and therefore defects) to be evacuated during consolidation. This reduces the cycle times and the energy consumed for consolidation, as well as the residual porosity rate.

[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 comprises 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, then a cooling step within the mold of the consolidated preform.

[0119] The heating step is carried out at a temperature higher than 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 a pressure between 1 bar and 25 bars, in particular between 5 bars and 10 bars, in particular between 6 bars and 8 bars.

[0121] This heating step makes it possible to weld the different layers of ribbons constituting the preform together. The heating temperature is therefore determined according to the nature of the ribbons (10) chosen.

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

[0123] By "fit together", we mean, in the sense of the present invention, to assemble or fit together. The textile preform, for example of cylindrical shape, will fit a part also of cylindrical shape, but of diameter, for example, substantially greater, so that the surfaces of each of the parts are in contact with each other. For example, the internal surface of the preform may be in contact with the external surface of the ring or the internal surface of the ring may be in contact with the external surface of the preform.

[0124] Co-consolidation allows the fusion of the polymer matrices of the parts and thus their adhesion 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 take the shape of the mold. This softened preform will be sandwiched between the wall of the mold 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 nested part, which in particular makes it possible to obtain good consolidation of the preform and also to improve the welding, and therefore the mechanical resistance, between the preform and the nested part.

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

[0129] Then, a cooling step is carried out in the mold, still under pressure. The cooling step allows the composite part to solidify. It is therefore essential that it is 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, consolidation step ii) is carried out after placing the mold and the preform under vacuum, 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 a preform to be obtained and step ii) allows the co-consolidation of this preform with one or more other parts, such as rings, connectors, fittings, or any other part.

[0133] The consolidation step comprising heating then cooling can be a few minutes, i.e. 3 minutes, or on the contrary can be slow, i.e. of the order of 1 hour using low-energy 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 manufacturing cycle time of 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 specific features to the consolidated part (for example reinforced plastic sleeves to subsequently assemble the tubes together or with other composite parts).

[0137] Step iii)

[0138] The method comprises 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 room temperature and the crystallization temperature, more favorably between the crystallization temperature and the glass transition temperature, more particularly still between the glass transition temperature and the glass transition temperature + 40°C.

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

[0140] Thus, the composite part obtained has very good mechanical strength, superior to that obtained with the wet filament winding processes or winding of conventional thermoplastic composite ribbons. Indeed, these processes do not offer the possibility of applying high pressure for a long time, and in particular when the matrix is ​​hot, that is to say during the phase of 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 matrix of the composite, the crystallization of the resin will be optimal, which will improve the quality of mechanical and chemical resistance of the composite obtained.

[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 a closed mold, then demolding, is much lower than the cycle time of current processes, such as wet filament winding or winding of thermoplastic composite ribbons.

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

[0144] According to another aspect, the invention relates to a hollow body made of composite material capable of being obtained according to the method 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 has allowed the fitting.

[0146] Generally speaking, the hollow body can be any element of a complex structure, whatever the field of activity.

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

[0148] The hollow body according to the invention may for example be a pipe for transporting fluid, which may incorporate a connection 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 sport, the hollow body can be, for example, the composite part can be a tennis racket, squash racket, padel racket, badminton racket, a trail stick, a ski pole, a ski lift pole, a hockey stick, a rowing component (oar, 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 the reference 1 aims at the manufacture of an elongated textile and unconsolidated element. For these purposes, the device 1 comprises a frame 2 comprising a main longitudinal guide 3 in a direction X, and at least two modules 4 arranged in series around the guide 3 in the direction X.

[0152] The main longitudinal guide 3 is fixed on 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 for the invention, other shapes of guide 3 are compatible with the invention. The guide 3 is rectilinear and can comprise sections of different shapes such as square, rectangular, quadrilateral, triangular, polygonal, round, oval, or of mixed and / or free shape.

[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 examples illustrated, the feed ring 5 has substantially the shape of a disc comprising a central hole in which the guide 3 is located.

[0154] A module 4 further comprises feed means 6 arranged on the crown 5. According to the illustrated embodiment, the feed means 6 are located on one face of the disc and feed at least one ribbon 10 towards the guide 3 with an angle relative to the direction X of between -90° and 90°.

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

[0156] The feed means 6 arranged on the crown 5 feed at least one ribbon 10 towards the guide 3 with a chosen angle between -90° and 90° relative to the direction X. Each ribbon 10 is wound at least around the guide 3 or on the layer of ribbon 10 already present, i.e. the upper layer with a chosen overall advance speed VI.

[0157] Each module 4 also comprises drive means 15 for the crown 5. According to [Fig.2] and also visible in [Fig.3], the drive means 15 are located on the face of the crown 5 opposite the feed means 6. The drive means 15 for the crown 5 make it possible to rotate the crown 5 around the guide 3 at a rotation speed V2. According to the illustrated embodiment, the drive means 15 comprise a motor comprising in particular a belt capable of rotating the crown 5 and a motor control unit in order to implement a rotation speed V2 of the crown 5. This configuration is not limiting for the invention.

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

[0159] [Fig.4] illustrates a module 4 comprising six dispensers 20 of ribbon 10. The dis dispensers 20 of ribbon 10 are arranged around the feed ring 5. According to the illustrated embodiments, a dispenser 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 according to a desired configuration and the pivoting means 22 can be locked according to the desired arrangement of the distributor 20.

[0161] [Fig. 5] illustrates a particular embodiment of the invention in which a dispenser 20 of ribbon 10 also comprises a guillotine 25 capable of cutting the ribbon 10 at the outlet of the dispenser 20, a motor M capable of feeding the ribbon after cutting and ultrasonic welding means 26 capable of welding a ribbon 10 at the level of a layer of ribbons 10 present or upper layer. The illustration of the motor M, the guillotine 25 and the welding means 26 is schematic in [Fig. 5] and other embodiments are possible and in particular with means of 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 dispensers 20 of ribbon 10 which each deposit a ribbon 10 in the direction of advancement X, that is to say that the angle between the ribbon 10 and the guide 3 has a value of 0 degrees. The second module 4 comprises two dispensers 20 of ribbon 10 and finally the third module 4 comprises a single dispenser 20 of ribbon 10. This embodiment is not limiting for the invention.

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

[0164] Preferably, the reels deliver the same ribbon 10 per module and each module 4 may comprise reels of ribbon 10 of different type.

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

[0166] A second step of the method consists in 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 feed 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 example of the device illustrated in Figures 6 and 7, a first layer of ribbon 10 is deposited with an angle close to 0° relative to the direction X, a second layer of ribbon 10 is deposited with an angle of approximately 80° relative to the direction X and a third layer is deposited with an angle close to -80° relative to the direction X.

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

[0168] Modules 4 are then started.

[0169] Depending on the nature of the ribbons 10, a pulling aid device 30 is implemented in order to assist in pulling 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 implemented. The ribbons 10 of the first layer can slide alone if their nature allows it or with manual assistance. The ribbons 10 of the other layers are deposited on the previous layer and then pass through the pulling aid device 30. This aid device 30 is not always necessary for implementing the method but it can assist in sliding the different layers towards 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 direction X, there is not necessarily a need for manual assistance to advance said ribbons 10.

[0171] According to another embodiment, once other layers of ribbons 10 are superimposed on the first layer, the elongated element 11 is manufactured without assistance and the pulling aid device 30 is no longer useful and can be removed. This may be a transitional period of start-up assistance which is necessary if the nature of the ribbon 10 used does not allow the ribbon to deploy efficiently from its reel 21.

[0172] The elongated element 11 which is 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 according to the desired size and according to the additional steps described below, for example increasing or of reduction of dimensions.

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

[0174] for assisting in pulling the ribbons 10. In fact, when it is wound, the textile element 11 causes the ribbons 10 which form it to be pulled.

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

[0176] The obtained unconsolidated textile elongated element 11 can finally be recovered. Consolidation steps can then be applied to it, for example a thermoforming step when the dimensions allow it. When consolidating the elongated element 11, it is also possible to slightly vary the dimensions of the elongated element 11, in particular its perimeter, of the order of 10-20%.

[0177] According to a particular embodiment, a secondary longitudinal guide (not shown) is arranged at the level of the first module 4 during manufacture. This secondary guide of diameter or section greater than the diameter or section of the main guide 3 is placed upstream of the first module 4 and translates towards the direction of manufacture of the elongated element 11. The ribbons 10 of the different modules 4 are then deposited on the secondary guide, and again on the main guide 3 after the secondary guide has passed. It is thus also possible to significantly increase the diameter or section or even overall shape of the elongated element 11 during its manufacture.

[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] shows 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 co-consolidated part with the rings at its ends.

[0181] [Fig. 12] is a perspective view of an elongated textile preform 44 that is not consolidated and bent. This preform is obtained following manufacturing step i) and after a bending step.

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

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

Claims

Claims

1. 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 using a device (1) comprising: - a frame (2) comprising a main longitudinal guide (3) in 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) in 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 ribbon (10) towards the guide (3) at a winding angle of between -90° and 90° with the direction X and at a feed speed VI, each ribbon (10) being capable of winding at least around the guide (3) or on the upper layer of ribbon (10), and - drive means (15) of the ring (5) capable of rotating the ring (5) around the guide (3) at a rotation speed V2, Said preform being manufactured according to a process comprising the steps of: - Implementation of the supply means (6) on each of the modules (4), said supply means (6) comprising selected ribbons (10), said selected ribbons (10) comprising at least thermoplastic composite ribbons - Setting the feed 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 unconsolidated elongated textile preform (11) obtained; the elongated, unconsolidated textile preform having a constant 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. Method according to claim 1 or 2, wherein the heating step of step ii) is carried out at a pressure of 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 preceding claim, wherein a bending step is performed before the consolidation step ii'»

5. n j. A method according to any preceding claim, wherein the thermoplastic composite tapes comprise: - Continuous or discontinuous reinforcing fibers of an inorganic or natural material; and - A thermoplastic polymer composition.

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; polyarylsulfides, in particular polyphenylene sulfides (PPS); polyamides (PA); PEBAs, 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, 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. The method of 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 a mixture 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 preceding claim, wherein the fibers of the thermoplastic composite ribbons are unidirectional, i.e. all oriented along the length of the ribbon.

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 preceding claim, wherein the selected ribbons (10) further comprise non-composite ribbons (10) of thermoplastic polymer.

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

15. Method according to claim 14, in which the polymer composition constituting the non-composite thermoplastic ribbons (10) mainly comprises a polyamide, preferably semi-crystalline.

16. Method according to claim 15, in which 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. Method according to any one of the preceding claims, in which the ribbons (10) have a thickness of between 50 and 300 pm, in particular between 50 and 260 pm and more particularly between 60 pm and 170 pm.

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

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

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

21. Hollow body made of composite material capable of being obtained according to the method as defined in claims 1 to 20.

22. Use of the composite hollow body as defined in claim 21, as a pipe for transporting 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 snowshoe frame, a ski pole, a hiking pole, a hockey stick, a golf club, a rowing element (oar, canoe, kayak).

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