METHOD FOR PRODUCE A FIBER MATERIAL FROM CONTINUOUS FIBERS IMPRECISED WITH A THERMOPLASTIC POLYMER

Description

[0001] The present invention relates to a method of manufacturing a continuous fiber fibrous material impregnated with thermoplastic polymer.

[0002] More particularly, the invention relates to a method for manufacturing an impregnated fibrous material comprising a fibrous material made of continuous fibers and at least one thermoplastic polymer matrix, said fibrous material being sized with at least one thermoplastic sizing polymer and having, before its pre-impregnation with said thermoplastic polymer, an initial width I, and comprising a step of spreading said fibrous material before a pre-impregnation step. It also relates to the use of the above method for manufacturing calibrated ribbons suitable for the manufacture of three-dimensional composite parts and to composite parts as such.

[0003] In this description, the term "fibrous material" means an assembly of reinforcing fibers. Before being shaped, it is in the form of strands. After being shaped, it is in the form of ribbons (or tapes), bands, or sheets. Their assembly constitutes a unidirectional reinforcement or a fabric or a non-woven fabric (NCF).

[0004] In this description, the term "strip" is used to designate strips of fibrous material whose width is greater than or equal to 400 mm. The term "ribbon" is used to designate ribbons of calibrated width less than or equal to 400 mm.

[0005] The quality of impregnation of thermoplastic polymers, in particular those of high viscosity, on continuous reinforcing fibers to make thermoplastic pre-impregnated tapes or ribbons requires perfect control of the quantity of impregnated polymer and the quality of distribution of this polymer within the strand of continuous reinforcing fibers during the impregnation process.

[0006] Document EP1172191 describes a composite part comprising a size and a thermoplastic matrix and a method of manufacturing said part.

[0007] Document US5895622 also describes a composite part comprising a size and a thermoplastic matrix and a method of manufacturing said part.

[0008] Document EP3170638 also describes a composite part comprising a size and a thermoplastic matrix and a method of manufacturing said part.

[0009] Several patent applications in the prior art such as WO2018 / 229114, WO2018 / 234436, WO2018 / 234439, EP 2788408 describe that the spreading of the fibers is an essential parameter for obtaining a homogeneous quality of polymer impregnation within the fibers on the final tape. In particular, if we refer to conventional impregnation processes such as aqueous or solvent-based dispersion of powders, but also and especially to the fluidized bed pre-impregnation process of powders, it is essential to have a high spreading rate of the fiber wick during the polymer loading step; that is to say during immersion in the pre-impregnation tank. This expansion must not only be significant but also homogeneous in the width of the fiber wick and constant over time in the pre-impregnation tank to ensure good quality and good consistency of impregnation of the final tape.

[0010] Generally speaking, the spreading of reinforcing fibers, such as carbon fibers, is generated via mechanical, pneumatic and / or vibratory systems. The main disadvantage of these methods is to generate misalignment of fibers within a roving (blowing or suction spreading) and / or mechanical degradation of the fibers by applying too high a transverse stress.

[0011] The use of these conventional systems is generally not sufficient to maintain sufficient, sufficiently homogeneous and constant expansion, particularly for sized fibers. This is even more true for fibers with a thermoplastic sizing. Indeed, this type of thermoplastic sizing is often dense and elastic and therefore accepts little deformation under external stress. In addition, since this sizing acts as a binder at room temperature between the filaments of the fiber strand, it is very complicated to strongly expand a strand with this type of sizing. The expansion generated by this type of conventional system on thermoplastic sized fiber strands is therefore weak, inhomogeneous across the width of the fiber strand and is only ephemeral and difficult to preserve. It is therefore not constant over time.

[0012] This expansion must be generated as close as possible to the pre-impregnation tank to be profitable and must also be maintained at a certain level during this pre-impregnation stage without mechanically degrading the fiber or misaligning the fibers within the wick. Furthermore, the systems currently used are generally bulky and / or unsuitable for the working conditions and environments (powder, solvent, water, temperature, etc.). They cannot therefore be as close as possible or even inside the pre-impregnation system.

[0013] It is therefore necessary to have a process in place to avoid the problems listed above.

[0014] The present invention relates to a method for manufacturing an impregnated fibrous material comprising a fibrous material made of continuous fibers and at least one thermoplastic polymer matrix, characterized in that said fibrous material is sized with a thermoplastic sizing polymer and has, before its pre-impregnation with said thermoplastic polymer, an initial width l, said method comprising a step of spreading said fibrous material before a pre-impregnation step, said spreading step being carried out by means of at least two shoring pieces (E) and at least one heating system SC allowing the heating of said shoring pieces and / or said fibrous material, said spreading after running of said fibrous material in contact with said shoring pieces being comprised from 1.5 to 5 times the initial width l,said expanded fibrous material being cooled below the Tg of the thermoplastic sizing polymer by means of a cooling system before it is brought into contact with said thermoplastic polymer matrix in the pre-impregnation system to carry out the pre-impregnation step, the expansion being constant and always representing 1.5 to 5 times the initial width l when said fibrous material is brought into contact with said thermoplastic polymer matrix in the pre-impregnation system.,

[0015] The term "sizing" refers to the surface treatments applied to fibrous materials during their manufacture of an organic nature (thermosetting resin or thermoplastic resin type)

[0016] In the context of the present invention, said fibrous material is therefore sized with a thermoplastic resin which may be semi-crystalline (PEEK, PEKK, polyamide-based sizing for example) or amorphous (PEI or polyamide-based sizing for example).

[0017] The thermoplastic resin is in particular a polyamide PA6 or PA66, generally of low molar mass. The size can also be of the polypropylene (PP) type, in particular for glass fibers.

[0018] Said fibrous material comprises up to 3% by weight of said thermoplastic sizing resin.

[0019] The term "broadening" refers to the factor by which the width of the fibrous material (or roving) increases compared to the initial width l of said roving, i.e. when said roving enters the system ensuring the broadening step. It is obvious that this is an average width (whether the initial width or the width after broadening) of the roving, flat, determined by averaging measurements obtained without contact (LASER, LED, etc.) on several reels. The initial width does not necessarily correspond to the width of the roving at the outlet of the reels 11.

[0020] The blooming step is carried out before the pre-impregnation step, which means that the blooming step is carried out either upstream of the pre-impregnation system, and therefore outside said system, or in the pre-impregnation system and therefore inside but before bringing the fibrous material into contact with the thermoplastic polymer in a solid, liquid (molten or dissolved) or suspended form.

[0021] The development is carried out at the level of the various pieces of tying E present which are located, as indicated above, outside or inside the pre-impregnation system by means of a heating system SC which makes it possible to heat either the fibrous material, or said tying E, or both.

[0022] The development depends on the fibrous material used and the different linear weights or titles or counts or "tex" and / or the number in the strands.

[0023] When said fibrous material passes in contact with said ties E, it is heated by said heating system either directly by said heating system SC which is then placed above the ties, or by said ties part which is then itself equipped with a heating system SC or by both.

[0024] Heating said fibrous material allows the sizing to soften and thus leads to a wider expansion of said fibrous material, expansion which is then maintained throughout said expansion step. The expansion obtained after passing over the last tying piece depends on the material used but the expansion factor after passing over the last tying piece is between 1.5 and 5 times the width of the fibrous material which came into contact with said first tying piece.

[0025] The heating temperature used must be above the Tg of the said thermoplastic polymer to cause softening of the size but must not exceed the Tf if the thermoplastic polymer used is semi-crystalline. In any case, it must not exceed 200°C for fibers with polyamide size. The temperature is measured using a pyrometer or a thermal camera.

[0026] Tf is determined by differential scanning calorimetry (DSC) according to ISO 11357-3:2013 and Tg is determined by differential scanning calorimetry (DSC) according to ISO 11357-2:2013.

[0027] Before bringing said expanded fibrous material into contact with the pre-impregnation system, that is to say before bringing the sized, heated and expanded fibrous material into contact with the thermoplastic polymer matrix in a solid, liquid (molten or dissolved) or suspended form, in particular in a solid powder form, said sized, heated and expanded fibrous material is cooled by a cooling system which may be ambient air or pulsed air.

[0028] Cooling is carried out until the temperature of said fibrous material is lower than the Tg of said thermoplastic sizing polymer. The cooling temperature is measured via a pyrometer or a thermal camera.

[0029] The expansion of said fibrous material after cooling when said fibrous material is brought into contact with said thermoplastic polymer in the pre-impregnation system is then always between 1.5 and 5 times the initial width l of said fibrous material. The expansion of said fibrous material is therefore constant between the end of the movement of said fibrous material in contact with said snares and the contact of said fibrous material with said thermoplastic polymer matrix in the pre-impregnation system.

[0030] The term "constant" means that the expansion does not vary by more than 10% between the end of the movement of said fibrous material in contact with said snares and the contacting of said fibrous material with said thermoplastic polymer matrix in the pre-impregnation system.

[0031] This expansion is also homogeneous in the width of the fiber wick and constant over time in the pre-impregnation tank to ensure good quality and good consistency of impregnation of the final impregnated fiber material.

[0032] The inventors therefore unexpectedly found that heating a fibrous material sized with a thermoplastic polymer and / or heating the packing parts with which said sized fibrous material is in contact made it possible, on the one hand, to expand said fibrous material more significantly than without heating, and on the other hand to maintain said expansion constant and homogeneous during the expansion step, but also to maintain this expansion after cooling and when said sized fibrous material is brought into contact with said thermoplastic polymer matrix. Regarding the docking parts

[0033] The term "locking parts (E)" means any system on which the bit can move. The at least two locking parts (E) can have any shape as long as the bit can move on them. They can be fixed or rotating (or rotary), preferably in co-rotation and / or alternatively in controlled counter-rotation.

[0034] In one embodiment, said anchoring part is in controlled rotation, in particular in such a way that the linear speed (in other words the tangential speed) at the surface of the anchoring is less than 2 times the speed of the bit or greater than 2 times the speed of the bit.

[0035] This means, for controlled rotation, that the tangential speed at the surface of the shim (E) is either equal to, greater than, or less than the speed of the bit. Advantageously, the linear speed (in other words the tangential speed) at the surface of the shim is less than 2 times the speed of the bit or greater than 2 times the speed of the bit.

[0036] More advantageously, the linear speed (in other words the tangential speed) at the surface of the anchor is less than 2 times the speed of the bit.

[0037] In one embodiment, the tangential speed of the snags is between 0.5 and 1.5 m / min, the speed of the bit being between 5 and 15 m / min.

[0038] The heating system is any system that releases heat or emits radiation capable of heating the fibrous material and / or the anchoring part (E). The anchoring parts (E) are therefore conductive or absorb the radiation emitted by the heat when they are heated at the same time as the fibrous material.

[0039] When only the fibrous material is heated, the packing parts are then non-conductive of heat

[0040] The term "heat-conducting enclosing parts (E)" means that the enclosing part (E) is made of a material capable of absorbing and conducting heat and thus of heating up.

[0041] The expression “non-heat-conducting rigging parts (E)” means that the rigging part (E) is made of a material incapable of absorbing and conducting heat, thus preventing any heating of said rigging parts (E).

[0042] Said at least two enclosing parts (E) are located or included in the environment of the heating system, that is to say they are not outside the heating system.

[0043] Said at least two enclosing parts (E) are therefore entirely inside the heating system but they are not necessarily surmounted by the heating system.

[0044] Advantageously, said heating system overcomes said at least two enclosing parts (E).

[0045] It would not be outside the scope of the invention if the shoring piece (E) were positioned in an oven comprising a heating system, for example by IR, but said shoring piece was not positioned exactly under the heating elements, for example by IR. It would not be outside the scope of the invention if the oven comprised a convection heating mode and an IR heating system.

[0046] It would also not be outside the scope of the invention if said shoring piece (E) placed in this furnace or in the environment of this furnace, were equipped with an autonomous heating means such as a resistor making it possible to heat said shoring piece (E), independently for example of the radiation from the IR lamps and the natural convection of the furnace and that, taking into account the speed of the line, the polymer present in the ribbons or wicks was still in the molten state when it came into contact with said shoring piece.

[0047] The SC heating system and the at least two swaging pieces can be located outside or inside the pre-impregnation system.

[0048] When the SC heating system and the at least two damming pieces are inside the pre-impregnation system, they are not in contact with the thermoplastic polymer in any form whatsoever (in powder, in aqueous or solvent-based dispersion or in melt). The SC heating system and the at least two damming pieces are therefore above the fluidized bed or the aqueous or solvent-based dispersion or the pultrusion system (melt process).

[0049] In a first variant, the heating system SC and the at least two embedding parts are located outside the pre-impregnation system and said pre-impregnation step is carried out with a system chosen from a fluidized bed, spray gun, aqueous dispersion and the molten route, in particular at high speed, in particular the pre-impregnation is carried out in a fluidized bed.

[0050] In another embodiment of this first variant, a single shoring part is present under the heating system SC which then corresponds to the first shoring part, the second shoring part being the roller (40) at the entrance to the tank.

[0051] In a second variant, the SC heating system and the at least two embedding parts are located inside the pre-impregnation system and said pre-impregnation step is carried out with a system chosen from a fluidized bed, gun spraying, aqueous dispersion, in particular the pre-impregnation is carried out in a fluidized bed.

[0052] In another embodiment of this second variant, a single shoring part is present under the heating system SC which then corresponds to the second shoring part, the first shoring part being the roller (40) at the entrance to the tank.

[0053] In one embodiment of either of the two variants above, said at least two enclosing parts (E) are heat-conducting and a heating means SC is present and integrated into said at least two enclosing parts (E).

[0054] The integrated heating means may be a resistor which is placed inside the docking parts or the docking parts may be equipped with a double jacket in which a heated fluid circulates making it possible to regulate or thermostat the temperature of said docking parts (E).

[0055] In one embodiment of either of the two variants above, said at least two shoring pieces (E) are heat conductive and a heating means SC is present above said at least two shoring pieces (E) making it possible to heat the fibrous material and said at least two shoring pieces (E).

[0056] Advantageously, the heating system is chosen from an infrared lamp, a UV lamp and convection heating.

[0057] In one embodiment of either of the two variants above, said at least two shoring pieces (E) are heat conductive and a heating means SC is present and integrated into said at least two shoring pieces (E) and a heating means SC is present above said at least two shoring pieces (E) for heating the fibrous material and said at least two shoring pieces (E).

[0058] In yet another embodiment, at least one of the sizing parts (E) can be cooled to control the temperature of the fibrous material and in particular not to exceed 200°C so as not to degrade the sizing of said fibrous material.

[0059] Cooling can be carried out by projection of cooled air or by circulation of a fluid cooled to the required temperature in at least one housing part provided with a double jacket.

[0060] In one embodiment of either of the two variants above, said at least two shoring pieces (E) are non-heat conductive and a heating means SC is present above said at least two shoring pieces (E) making it possible to heat the fibrous material.

[0061] Advantageously, the at least two clamping parts (E) are compression rollers of convex, concave or cylindrical shape, preferably cylindrical.

[0062] The number of rollers in contact with said fibrous material is from 2 to 20, in particular from 2 to 12, in particular from 2 to 9, preferably from 6 to 9.

[0063] Advantageously, the distance between two adjacent rollers is from 50 to 2000 µm, in particular from 50 to 500 µm, in particular from 50 to 120 µm. This distance may or may not be the same across all of the snares concerned; an exemplary embodiment may thus result in a system having a distance between two adjacent rollers of 1000 µm at the start of the spreading system (in the direction of travel of the roving) and a distance between two adjacent rollers of 200 µm at the end of the spreading system (in the direction of travel of the roving).

[0064] Advantageously, the rollers are cylindrical and have a diameter D ranging from 5 to 100 mm, in particular from 5 to 50 mm, in particular from 10 to 30 mm.

[0065] Advantageously, the last roller of the spreading system when said rollers are outside or when only one roller is outside, the second being the edge of said tank, is at a distance from the fluidization tank and therefore from the roller of the edge of the tank less than or equal to 30 cm. Beyond 30 cm, the spreading is no longer constant and decreases when the fibrous material enters said tank.

[0066] We can simply calculate i the distance between two adjacent rolls of the same diameter (µm): i = L 2 + L ′ 2 − D × 10000 , i, expressed in µm, being necessarily a positive number, the rollers not being able to interpenetrate. L: Distance between the centers of the two sets of rollers (mm) L': distance between each adjacent roller (mm) D: diameter of the rollers (mm)

[0067] This equation can be applied regardless of the number of rolls, as long as they have the same diameter.

[0068] For rollers of different diameters but each roller in each row being at the same level and having the same diameter, the equation is then: L 2 + L ′ 2 = D 1 + D 2 / 2 + i 2 D1: diameter of the rollers of the lower row of the figure 7 (mm) D2: diameter of the rollers of the upper row of the figure 7 (mm)

[0069] Furthermore, said fibrous material, due to the presence of the anchoring parts as close as possible to the pre-impregnation system, and in particular as close as possible to the contact of said fibrous material with said thermoplastic polymer of the matrix, is not misaligned and the number of anchoring parts prevents the fiber from breaking.

[0070] In one embodiment, said compression rollers are co-rotating and / or counter-rotating.

[0071] In another embodiment, said compression rollers are vibrating.

[0072] Said compression rollers may have a surface treatment and / or an apparent surface roughness minimizing friction with the reinforcing fibers.

[0073] This limits tension / friction forces and mechanical degradation of the fiber by choosing a surface treatment for the compression rollers which minimizes friction with the fiber.

[0074] The surface treatment can be topocrom ®< , an aluminum and titanium oxide deposited on the rollers. These treatments can affect the apparent roughness of the compression roller and / or the “physicochemical” nature of the contacts (natural lubrication).

[0075] Advantageously, said rollers are spaced apart from each other by a distance of less than 30 cm, in particular between D / 2 + 1 mm and 30 cm, D being the diameter of the roller.

[0076] In one embodiment, the distance between the last roller and a point of contact between the reinforcing fiber and an element of the following process is less than 30 cm.

[0077] This distance allows for the preservation of development.

[0078] The height between the heating system and the jambs is between 1 and 100 cm, preferably between 2 and 30 cm, in particular between 2 and 10 cm.

[0079] The heating system may be a horizontal system. However, the heating system(s) may be arranged vertically with the wick also running vertically through the shackles. Regarding the fibrous material

[0080] Regarding the fibers making up the said fibrous material, these are in particular fibers of mineral, organic or vegetable origin. Among the fibers of mineral origin, we can cite carbon fibers, glass fibers, silicon carbide, basalt or basalt-based fibers, silica fibers, for example.

[0081] Among the fibers of organic origin, we can cite fibers based on thermoplastic or thermosetting polymer, such as semi-aromatic polyamide fibers, aramid fibers or polyolefin fibers for example.

[0082] Preferably, they are based on amorphous thermoplastic polymer and have a glass transition temperature Tg greater than the Tg of the polymer or mixture of thermoplastic polymers constituting the pre-impregnation matrix when the latter is amorphous, or greater than the Tf of the polymer or mixture of thermoplastic polymers constituting the pre-impregnation matrix when the latter is semi-crystalline. Advantageously, they are based on semi-crystalline thermoplastic polymer and have a melting temperature Tf greater than the Tg of the polymer or mixture of thermoplastic polymers constituting the pre-impregnation matrix when the latter is amorphous, or greater than the Tf of the polymer or mixture of thermoplastic polymers constituting the pre-impregnation matrix when the latter is semi-crystalline.Thus, there is no risk of fusion for the organic fibers constituting the fibrous material during impregnation by the thermoplastic matrix of the final composite.

[0083] Among the fibers of plant origin, we can cite natural fibers based on flax, hemp, lignin, bamboo, silk, especially spider silk, sisal, and other cellulosic fibers, in particular viscose. These fibers of plant origin can be used pure, treated or coated with a coating layer, in order to facilitate the adhesion and impregnation of the thermoplastic polymer matrix.

[0084] The fibrous material can also be a fabric, braided or woven with fibers.

[0085] It can also correspond to fibers with holding threads.

[0086] These constituent fibers can be used alone or in mixtures. Thus, organic fibers can be mixed with mineral fibers to be pre-impregnated with thermoplastic polymer and form the pre-impregnated fibrous material.

[0087] Preferably the fibrous material consists of continuous carbon, glass or silicon carbide fibers or their mixture, in particular carbon fibers. It is used in the form of a strand or several strands.

[0088] In impregnated materials, also called "ready-to-use", the thermoplastic impregnating polymer or polymer blend is distributed uniformly and homogeneously around the fibers. In this type of material, the thermoplastic impregnating polymer must be distributed as homogeneously as possible within the fibers in order to obtain a minimum of porosity, i.e. a minimum of voids between the fibers. Indeed, the presence of porosities in this type of material can act as stress concentration points, during mechanical tensile stress for example, and which then form fracture initiation points of the impregnated fibrous material and weaken it mechanically. A homogeneous distribution of the polymer or polymer blend therefore improves the mechanical strength and homogeneity of the composite material formed from these impregnated fibrous materials.

[0089] Thus, in the case of so-called "ready-to-use" impregnated materials, the fiber content in said impregnated fibrous material is from 45 to 65% by volume, preferably from 50 to 60% by volume, in particular from 54 to 60% by volume.

[0090] The measurement of the impregnation rate can be carried out by image analysis (using a microscope or camera or digital camera, in particular), of a cross-section of the ribbon, by dividing the surface of the ribbon impregnated by the polymer by the total surface of the product (impregnated surface plus surface of the porosity). In order to obtain a good quality image, it is preferable to coat the ribbon cut in its transverse direction in a standard polishing resin and to polish with a standard protocol allowing the observation of the sample under a microscope at a magnification of at least 6 times.

[0091] Advantageously, the porosity rate of said impregnated fibrous material is less than 10%, in particular less than 5%, in particular less than 2%.

[0092] It should be noted that a zero porosity rate is difficult to achieve and that consequently, advantageously the porosity rate is greater than 0% but lower than the rates cited above.

[0093] The porosity rate corresponds to the closed porosity rate and can be determined either by electron microscopy or as the relative difference between the theoretical density and the experimental density of said impregnated fibrous material as described in the examples section of the present invention.

[0094] The fibers that can be used in the composition of fibrous materials can have different linear weights or counts or "tex" and / or be in different numbers in the strands. Also, the most commonly used strands are composed of 600 to 4800 tex for glass fibers and 3000 (3K), 6000 (6K), 12000 (12K), 24000 (24K), 48000 (48K), 50,000 (50K) or 400,000 (400K) fibers for carbon fibers. Carbon fibers generally have a diameter close to 7-8 µm and glass fibers a diameter of approximately 13, 15, 17 or 20 µm for example.

[0095] It is quite obvious that the development is a function of the number of fibers present in the fibrous material or wick.

[0096] Thus, for a 12K wick the expansion represents 2 to 3 times the initial width l. For a 24K wick the expansion represents 2 to 4 times the initial width l and for a 50K wick the expansion represents 1.5 to 2.5 times the initial width l. Regarding the thermoplastic polymer of the matrix

[0097] Thermoplastic, or thermoplastic polymer, is understood to mean a material that is generally solid at room temperature, which may be semi-crystalline or amorphous, and which softens upon increasing temperature, in particular after passing its glass transition temperature (Tg) and flows at a higher temperature when it is amorphous, or which may exhibit a clear melting upon passing its so-called melting temperature (Tf) when it is semi-crystalline, and which becomes solid again upon decreasing temperature below its crystallization temperature (for a semi-crystalline material) and below its glass transition temperature (for an amorphous material).

[0098] Tg and Tf are determined by differential scanning calorimetry (DSC) according to standard 11357-2:2013 and 11357-3:2013 respectively.

[0099] Concerning the polymer constituting the pre-impregnation matrix of the fibrous material, it is advantageously a thermoplastic polymer or a mixture of thermoplastic polymers. This polymer or mixture of thermoplastic polymers can be ground into powder form, in order to be able to use it in a device such as a tank, in particular in a fluidized bed or in aqueous dispersion.

[0100] The device in the form of a tank, in particular a fluidized bed, can be open or closed. Optionally, the thermoplastic polymer or mixture of thermoplastic polymers further comprises carbon fillers, in particular carbon black or carbon nanofillers, preferably chosen from carbon nanofillers, in particular graphenes and / or carbon nanotubes and / or carbon nanofibrils or mixtures thereof. These fillers make it possible to conduct electricity and heat, and therefore make it possible to facilitate the melting of the polymer matrix when it is heated.

[0101] Optionally, said thermoplastic polymer comprises at least one additive, in particular chosen from a catalyst, an antioxidant, a thermal stabilizer, a UV stabilizer, a light stabilizer, a lubricant, a filler, a plasticizer, a flame retardant, a nucleating agent, a chain extender and a colorant, an electrically conductive agent, a thermally conductive agent or a mixture thereof.

[0102] Advantageously, said additive is chosen from a flame retardant agent, an electrically conductive agent and a thermally conductive agent.

[0103] According to another variant, the thermoplastic polymer or mixture of thermoplastic polymers may also comprise liquid crystal polymers or cyclized poly(butylene terephthalate), or mixtures containing them, such as the CBT100 resin marketed by the company CYCLICS CORPORATION. These compounds make it possible in particular to fluidify the polymer matrix in the molten state, for better penetration into the heart of the fibers. Depending on the nature of the polymer, or mixture of thermoplastic polymers, used to produce the pre-impregnation matrix, in particular its melting temperature, one or the other of these compounds will be chosen.

[0104] The thermoplastic polymers used in the composition of the pre-impregnation matrix of the fibrous material can be chosen from: polymers and copolymers of the family of aliphatic, cycloaliphatic or semi-aromatic polyamides (PA) (also called polyphthalamides (PPA)), PEBAs, polyureas, in particular aromatic, polymers and copolymers of the acrylic family such as polyacrylates, and more particularly polymethyl methacrylate (PMMA) or its derivatives polymers and copolymers of the family of poly(aryletherketones) (PAEK) such as poly(etheretherketone) (PEEK), or poly(aryletherketoneketones) (PAEKK) such as poly(etherketoneketone) (PEKK) or their derivatives, aromatic polyetherimides (PEI), polyarylsulfides, in particular polyphenylene sulfides (PPS), polyarylsulfones, in particular polyphenylene sulfones (PPSU), polyolefins, in particular polypropylene (PP);polylactic acid (PLA), polyvinyl alcohol (PVA), fluoropolymers, in particular polyvinylidene fluoride (PVDF), or polytetrafluoroethylene (PTFE) or polychlorotrifluoroethylene (PCTFE), ; and their mixtures.

[0105] Advantageously, when said polymer is a mixture of two polymers P1 and P2, the proportion by weight of polymer P1 and P2 is from 1-99% to 99-1%.

[0106] Advantageously, when said thermoplastic polymer is a mixture, and the pre-impregnation process uses a dry powder, this mixture is in the form of a powder obtained either by "dry blend" before introduction into the pre-impregnation tank or by "dry blend" produced directly in the tank or even by grinding a compound produced beforehand in an extruder.

[0107] Advantageously, this mixture is composed of a powder obtained by “dry blend”, before introduction into the tank or directly into the tank, and this mixture of two polymers P1 and P2 is a mixture of PEKK and PEI.

[0108] Advantageously, the PEKK / PEI mixture is from 90-10% to 60-40% by weight, in particular from 90-10% to 70-30% by weight.

[0109] The thermoplastic polymer may correspond to the final non-reactive polymer which will impregnate the fibrous material or to a reactive prepolymer, which will also impregnate the fibrous material, but is likely to react on itself or with another prepolymer, depending on the chain ends carried by said prepolymer, after pre-impregnation, or even with a chain extender and in particular during heating at the level of the skewers in the oven and / or during the implementation of the tape in the final manufacturing process of the composite part.

[0110] The expression "non-reactive polymer" means that the molecular weight is no longer likely to change significantly, that is to say that its number-average molecular mass (Mn) changes by less than 50% during its processing and therefore corresponds to the final polyamide polymer of the thermoplastic matrix.

[0111] Conversely, the expression "reactive polymer" means that the molecular weight of said reactive polymer will change during processing by reaction of reactive prepolymers with each other by condensation, substitution or with a chain extender by polyaddition and without elimination of volatile by-products to lead to the final (non-reactive) polyamide polymer of the thermoplastic matrix.

[0112] According to a first possibility, said prepolymer may comprise or consist of at least one reactive prepolymer (polyamide) carrying on the same chain (i.e. on the same prepolymer), two terminal functions X' and Y', functions respectively coreactive with each other by condensation, more particularly with X' and Y' being amine and carboxy or carboxy and amine respectively. According to a second possibility, said prepolymer may comprise or consist of at least two polyamide prepolymers reactive with each other and each carrying respectively two terminal functions X' or Y', identical (identical for the same prepolymer and different between the two prepolymers), said function X' of one prepolymer being able to react only with said function Y' of the other prepolymer, in particular by condensation, more particularly with X' and Y' being amine and carboxy or carboxy and amine respectively.

[0113] According to a third possibility, said prepolymer may comprise or consist of at least one prepolymer of said thermoplastic polyamide polymer, bearing n terminal reactive functions X, chosen from: -NH2, -CO2H and -OH, preferably NH2 and -CO2H with n being 1 to 3, preferably from 1 to 2, more preferably 1 or 2, more particularly 2 and at least one chain extender Y-A'-Y, with A' being a hydrocarbon biradical, bearing 2 identical terminal reactive functions Y, reactive by polyaddition with at least one function X of said prepolymer a1), preferably of molecular mass less than 500, more preferably less than 400.

[0114] The number average molecular mass Mn of said final polymer of the thermoplastic matrix is ​​preferably in a range from 10000 to 40000, preferably from 12000 to 30000. These Mn values ​​may correspond to inherent viscosities greater than or equal to 0.8 as determined in m-cresol according to ISO 307:2007 but by changing the solvent (use of m-cresol instead of sulfuric acid and the temperature being 20°C).

[0115] Said reactive prepolymers according to the two options cited above have a number-average molecular mass Mn ranging from 500 to 10,000, preferably from 1,000 to 6,800, in particular from 2,500 to 6,800.

[0116] The Mn are determined in particular by calculation from the rate of terminal functions determined by potentiometric titration in solution and the functionality of said prepolymers. The Mn masses can also be determined by size exclusion chromatography or by NMR.

[0117] The nomenclature used to define polyamides is described in ISO 1874-1:2011 "Plastics - Polyamide (PA) materials for molding and extrusion - Part 1: Designation", particularly on page 3 (tables 1 and 2) and is well known to those skilled in the art.

[0118] The polyamide may be a homopolyamide or a copolyamide or a mixture thereof.

[0119] Advantageously, the prepolymers constituting the matrix are chosen from Polyamides (PA), in particular chosen from aliphatic polyamides, cycloaliphatic polyamides, and semi-aromatic polyamides (polyphthalamides) optionally modified by urea units, and their copolymers, Polymethyl methacrylate (PPMA) and its copolymers, Polyether imides (PEI), Poly(phenylene sulfide) (PPS), Poly(phenylene sulfone) (PPSU), PVDF, Poly(etherketoneketone) (PEKK), Poly(etheretherketone) (PEEK), fluorinated polymers such as poly(vinylidene fluoride) (PVDF).

[0120] For fluoropolymers, a vinylidene fluoride homopolymer (VDF with the formula CH 2 =CF 2 ) or a VDF copolymer comprising by weight at least 50% by mass of VDF and at least one other monomer copolymerizable with VDF can be used. The VDF content must be greater than 80% by mass, or even better 90% by mass, to ensure good mechanical and chemical resistance to the structural part, especially when it is subjected to thermal and chemical stresses. The comonomer can be a fluorinated monomer such as, for example, vinyl fluoride. For structural parts that have to withstand high temperatures, in addition to fluorinated polymers, PAEK (PolyArylEtherKetone) such as poly(ether ketones) PEK, poly(ether ether ketone) PEEK, poly(ether ketone ketone) PEKK, Poly(ether ketone ether ketone ketone) PEKEKK or PA with a high glass transition temperature Tg) are advantageously used according to the invention.

[0121] Advantageously, said thermoplastic polymer is a polymer whose glass transition temperature is such that Tg ≥ 80°C, in particular ≥ 100°C, in particular ≥ 120°C, in particular ≥ 140°C, or a semi-crystalline polymer whose melting temperature Tf ≥ 150°C.

[0122] Advantageously, said thermoplastic polymer of the matrix is ​​a non-reactive thermoplastic polymer.

[0123] Advantageously, said at least one thermoplastic prepolymer is selected from polyamides, PEKK, PEI and a mixture of PEKK and PEI. Advantageously, said polyamide is chosen from aliphatic polyamides, cycloaliphatic polyamides and semi-aromatic polyamides (polyphthalamides).

[0124] Advantageously, said aliphatic polyamide prepolymer is chosen from: polyamide 6 (PA6), polyamide 11 (PA11), polyamide 12 (PA12), polyamide 66 (PA66), polyamide 46 (PA46), polyamide 610 (PA610), polyamide 612 (PA612), polyamide 1010 (PA1010), polyamide 1012 (PA1012), polyamide 11 / 1010 and polyamide 12 / 1010, or a mixture thereof or a copolyamide thereof, and block copolymers, in particular polyamide / polyether (PEBA), and said semi-aromatic polyamide is a semi-aromatic polyamide, optionally modified with urea units, in particular a PA MXD6 and a PA MXD10 or a semi-aromatic polyamide of formula X / YAr, as described in EP1505099, in particular a polyamide semi-aromatic of formula A / XT in which A is chosen from a unit obtained from an amino acid, a unit obtained from a lactam and a unit corresponding to the formula (Ca diamine).(Cb diacid), with a representing the number of carbon atoms of the diamine and b representing the number of carbon atoms of the diacid, a and b each being between 4 and 36, advantageously between 9 and 18, the unit (Ca diamine) being chosen from aliphatic, linear or branched diamines, cycloaliphatic diamines and alkylaromatic diamines and the unit (Cb diacid) being chosen from aliphatic, linear or branched diacids, cycloaliphatic diacids and aromatic diacids; . XT denotes a unit obtained from the polycondensation of a Cx diamine and terephthalic acid, with x representing the number of carbon atoms of the Cx diamine, x being between 6 and 36, advantageously between 9 and 18, in particular a polyamide of formula A / 6T, A / 9T, A / 10T or A / 11T, A being as defined above, in particular a polyamide PA 6 / 6T, a PA 66 / 6T, a PA 6I / 6T, a PA MPMDT / 6T, a PA PA11 / 10T, a PA 11 / 6T / 10T, a PA MXDT / 10T, a PA MPMDT / 10T, a PA BACT / 10T, a PA BACT / 6T, PA BACT / 10T / 6T, PA BACT / 10T / 11, PA BACT / 6T / 11.

[0125] T stands for terephthalic acid, MXD stands for m-xylylenediamine, MPMD stands for methylpentamethylenediamine, and BAC stands for bis(aminomethyl)cyclohexane.

[0126] Advantageously, the thermoplastic polymer is a semi-aromatic polyamide. Advantageously, the thermoplastic polymer is a semi-aromatic polyamide selected from a PA MPMDT / 6T, a PA PA11 / 10T, a PA 11 / 6T / 10T, a PA MXDT / 10T, a PA MPMDT / 10T, a PA BACT / 10T, a PA BACT / 6T, PA BACT / 10T / 6T, PA BACT / 10T / 11, PA BACT / 6T / 11. Regarding the stage of pre-impregnation:

[0127] The pre-impregnation step as already indicated above can be carried out according to techniques well known to those skilled in the art and in particular chosen from those described above.

[0128] In an advantageous embodiment, the pre-impregnation step is carried out with a system chosen from a fluidized bed, spray gun and the melt route, in particular at high speed, in particular the impregnation is carried out in a fluidized bed.

[0129] Advantageously, the pre-impregnation is carried out with a system chosen from a fluidized bed, spray gun and the melt route, in particular at high speed, in particular the impregnation is carried out in a fluidized bed and one or more anchoring part(s) (E") is (are) present upstream of said system.

[0130] It should be noted that the anchoring parts (E) and (E") may be identical or different whether in terms of material or shape and its characteristics (diameter, length, width, height, etc. depending on the shape).

[0131] They can be at the same level or at different levels. The latter case is represented for example by the figure 7 .

[0132] The fluidized bed pre-impregnation process is described in WO 2018 / 115736.

[0133] Advantageously, the pre-impregnation step is carried out in a fluidized bed.

[0134] An example of a unit for implementing a manufacturing method without the heating step using at least one holding part is described in international application WO 2015 / 121583.

[0135] This system describes the use of a tank comprising a fluidized bed to carry out the pre-impregnation step and can be used within the scope of the invention.

[0136] Advantageously, the tank comprising the fluidized bed is provided with at least one locking part (E') which may be a compression roller).

[0137] It should be noted that the anchoring parts (E) and (E') may be identical or different in terms of material or shape and its characteristics (diameter, length, width, height, etc. depending on the shape).

[0138] However, the locking part (E') is neither heated nor heated.

[0139] The step of pre-impregnating the fibrous material is carried out by passing one or more strands through a continuous pre-impregnation device, comprising a tank (10) provided with at least one snubbing part (E') and comprising a fluidized bed (12) of powder of said polymer matrix.

[0140] The powder of said polymer or polymer matrix is ​​suspended in a gas G (air for example) introduced into the tank and circulating in the tank (10) through a hopper (11). The wick(s) are circulated in this fluidized bed (12).

[0141] The tank may have any shape, in particular cylindrical or parallelepiped, in particular a rectangular parallelepiped or a cube, advantageously a rectangular parallelepiped.

[0142] The tank (10) may be an open or closed tank. Advantageously, it is open.

[0143] In the case where the tank is closed, it is then equipped with a sealing system so that the powder of said polymer matrix cannot escape from said tank.

[0144] This pre-impregnation step is therefore carried out by the dry method, that is to say that the thermoplastic polymer matrix is ​​in powder form, in particular suspended in a gas, in particular air, but cannot be dispersed in a solvent or in water.

[0145] Each wick to be pre-impregnated after passing over the shims (E) enters the fluidized bed.

[0146] The fiber strand or the parallel fiber strands then pass into a tank (10), comprising in particular a fluidized bed (12), provided with at least one snaking part (E') which is a compression roller or is already present in the tank and then enters the fluidized bed (12), provided with at least one snaking part (E'). The fiber strand or the parallel fiber strands then exit(s) the tank after pre-impregnation after possible control of the residence time in the powder. The pre-impregnation method by spray gun is described in WO 2018 / 115739.

[0147] The melt pre-impregnation process is described in WO 2018 / 234439.

[0148] Advantageously, the pre-impregnation step is carried out by melting, in particular by pultrusion.

[0149] Melt pre-impregnation techniques are well known to those skilled in the art and are described in the above references.

[0150] The pre-impregnation step is carried out in particular by extrusion of the polymer matrix at the square head and passage of said wick or wicks into this square head and then passage into a heated die, the square head possibly being provided with fixed or rotating clamps on which the wick runs, thus causing said wick to expand, allowing pre-impregnation of said wick.

[0151] Pre-impregnation can also be carried out as described in US 2014 / 0005331 A1 with the difference that the resin supply is carried out on both sides of said wick and there is no contact surface eliminating part of the resin on one of the two surfaces.

[0152] Advantageously, the pre-impregnation step is carried out by high-speed melting, i.e. with a running speed of said wick or wicks greater than or equal to 5 m / min, in particular greater than 9 m / min.

[0153] In one embodiment, the method according to the invention comprises a step of heating the pre-impregnated fibrous material to melt the thermoplastic polymer of the matrix and finalize the impregnation of said fibrous material.

[0154] In another embodiment, the method according to the invention comprises a step of heating the pre-impregnated fibrous material to melt and polymerize the thermoplastic prepolymer of the matrix, optionally with said extender, and finalize the impregnation of said fibrous material.

[0155] Said heating step can be carried out as described in WO 2018 / 234439: A first heating step can be immediately consecutive to the pre-impregnation step or other steps can occur between the pre-impregnation step and the heating step, regardless of the system chosen to carry out the pre-impregnation step, and in particular with a system chosen from a fluidized bed, spray gun spraying and the molten route, in particular at high speed, in particular a fluidized bed.

[0156] Advantageously, said first heating step is immediately consecutive to the pre-impregnation step. The expression “immediately consecutive” means that there is no intermediate step between the pre-impregnation step and said heating step.

[0157] Advantageously, only one heating step is carried out, immediately following the pre-impregnation step.

[0158] Advantageously, said at least one heating system is chosen from an infrared lamp, a UV lamp and convection heating.

[0159] The fibrous material being in contact with the shim(s) in the heating system, and the shim(s) being conductive, the heating system therefore also takes place by conduction.

[0160] Advantageously, said at least one heating system is chosen from an infrared lamp.

[0161] Advantageously, said at least one blocking part (E") is a compression roller of convex, concave or cylindrical shape.

[0162] It should be noted that the compression rollers corresponding to the shoring parts (E), (E') and (E") may be identical or different whether in terms of material or shape and its characteristics (diameter, length, width, height ... depending on the shape).

[0163] The convex shape is favorable to blossoming while the concave shape is unfavorable to blossoming although it nevertheless occurs.

[0164] The at least one shoring part (E") may also be an alternation of convex and concave shape. In this case, the running of the wick on a compression roller of convex shape causes the said wick to expand, then the running of the wick on a compression roller of concave shape causes the retraction of the wick and so on, making it possible, if necessary, to improve the homogeneity of the impregnation, in particular at the core.

[0165] The expression "compression roller" means that the rolling wick rests partially or totally on the surface of said compression roller, which causes said wick to expand.

[0166] The rollers can be free (rotating) or fixed.

[0167] They can be smooth, ridged or grooved.

[0168] Advantageously, the rollers are cylindrical and striated. When the rollers are striated, two ridges may be present in opposite directions from each other starting from the center of said roller, thus allowing the strands to be moved away from the outside of the roller, or in opposite directions from each other starting from the outside of said roller, thus allowing the strands to be brought back towards the center of the roller.

[0169] This heating step makes it possible to homogenize the pre-impregnation, thus finalizing the impregnation and thus having a core impregnation and having a high rate of fibers by volume, in particular constant in at least 70% of the volume of the strip or ribbon, in particular in at least 80% of the volume of the strip or ribbon, in particular in at least 90% of the volume of the strip or ribbon, more particularly in at least 95% of the volume of the strip or ribbon, as well as reducing the porosity.

[0170] The amount of expansion depends on the fiber material used. For example, the expansion of a carbon fiber material is much greater than that of a linen fiber.

[0171] The development is also a function of the number of fibers in the wick, their average diameter and their cohesion due to the sizing.

[0172] The diameter of said at least one compression roller (barrage (E")) is between 3 mm and 100 mm, preferably between 3 mm and 20 mm, in particular between 5 mm and 10 mm.

[0173] Below 3 mm, the deformation of the fiber induced by the compression roller is too great.

[0174] Advantageously, the compression roller is cylindrical and not grooved and in particular is metallic.

[0175] Advantageously, said at least one blocking part (E") consists of at least one cylindrical compression roller.

[0176] Advantageously, said at least one locking part (E") consists of 1 to 15 compression rollers (R1 to R15) of cylindrical shape, preferably 3 to 15 compression rollers (R3 to R15), in particular 6 to 10 compression rollers (R6 to R10).

[0177] It is quite obvious that whatever the number of enclosing parts (E") present, they are all located or included in the environment of the heating system, that is to say they are not outside the heating system.

[0178] According to another aspect, the present invention relates to the use of the method as defined above, for the manufacture of calibrated ribbons suitable for the manufacture of three-dimensional composite parts, by automatic deposition of said ribbons by means of a robot.

[0179] In one embodiment, said composite parts relate to the fields of transport, in particular automotive, oil and gas, in particular offshore, hydrogen, gas storage, in particular hydrogen, aeronautics, nautical, railway; renewable energies, in particular wind, hydro turbine, energy storage devices, solar panels; thermal protection panels; sports and leisure, health and medical and electronics. Brief description of the figures

[0180] [ Fig. 1 ] presents a partial diagram of a unit for implementing the method for manufacturing a pre-impregnated fibrous material according to WO 2018 / 115736.

[0181] Each strand to be impregnated is unwound from a device 10 with reels 11 under the traction generated by cylinders (not shown). The device 10 comprises a plurality of reels 11, each reel making it possible to unwound a strand to be impregnated. Thus, it is possible to impregnate several strands of fibers simultaneously. Each reel 11 is provided with a brake (not shown) so as to apply tension to each strand of fibers. In this case, an alignment module 12 makes it possible to arrange the strands of fibers parallel to each other. In this way, the strands of fibers cannot be in contact with each other, which makes it possible to avoid mechanical degradation of the fibers in particular.

[0182] The fiber strand or parallel fiber strands then pass into a tank 20 of a fluidized bed 22 provided with at least one snare (E') (23), in particular a compression roller. The polymer powder(s) is suspended in a gas G (air for example) introduced into the tank and circulating in the tank through a hopper 21. The strand(s) are circulated in this fluidized bed 22.

[0183] [ Fig. 2 ] has a tank comprising a fluidized bed provided with at least one locking part (E') which may be a compression roller

[0184] [ Fig. 3 ] has a fluidized bed tank comprising a shim (E') on which the expanded and heated fibrous material circulates to carry out the pre-impregnation, the expansion step being carried out outside the impregnation system and the heating system SC (30) is integrated with the compression rollers (E).

[0185] The fibrous material enters the interior of the tank and exits by passing over the edge of the tank (40) which can be a fixed or movable roller.

[0186] The figure shows two rollers but the invention is not limited to this configuration.

[0187] [ Fig. 4 ] has a fluidized bed tank comprising a shim (E') on which the expanded and heated fibrous material circulates to carry out the pre-impregnation, the expansion step being carried out outside the impregnation system and the heating system SC (30) which can be an infrared system is located above the compression rollers (E).

[0188] The fibrous material enters the interior of the tank and exits by passing over the edge of the tank (40) which can be a fixed or movable roller.

[0189] The figure shows two rollers but the invention is not limited to this configuration.

[0190] [ Fig. 5] has a fluidized bed tank comprising a shim (E') on which the expanded and heated fibrous material circulates to carry out the pre-impregnation, the expansion step being carried out inside the impregnation system and the heating system SC (30) is integrated with the compression rollers (E) which are located above the fluidized bed.

[0191] The fibrous material enters the interior of the tank and exits by passing over the edge of the tank (40) which can be a fixed or movable roller.

[0192] The figure shows two rollers but the invention is not limited to this configuration.

[0193] [ Fig. 6] has a fluidized bed tank comprising a shim (E') on which the expanded and heated fibrous material circulates to carry out the pre-impregnation, the expansion step being carried out inside the impregnation system and the heating system SC (30) which can be an infrared system located above the compression rollers (E) which are located above the fluidized bed.

[0194] The fibrous material enters the interior of the tank and exits by passing over the edge of the tank (40) which can be a fixed or movable roller.

[0195] The figure shows two rollers but the invention is not limited to this configuration.

[0196] [ Fig. 7 ] has a system of six compression rollers (E) on two levels. Examples

[0197] Comparative example 1: Development stage using six shims (E) without heating system and located outside the pre-impregnation system The following procedure was carried out:

[0198] A system of 6 smooth cylindrical rollers distributed as shown in figure 7 in two rows of rollers, three being 25 mm in diameter on one row and three other rollers on another row being 20 mm in diameter.

[0199] The rollers have a Topocrom ® coating.

[0200] The roller system is located outside the tank.

[0201] The distance L between the two sets of upper and lower rollers is equal to 17 mm; the distance L between two adjacent rollers is equal to 15.2 mm and i = 300 µm (calculated by the equation given in figure 7 ) thus inducing a gap between the rollers of 300µm for the passage of the wick.

[0202] Wicks used: SIGRAFIL ®< T24-5.0 / 270-T140 from SGL Technologies GmbH, with thermoplastic sizing. Tension of the roving at the exit of the creel and before meeting the spreading system: 500g D50 = 108 µm, (D10 = 39µm, D90 = 194µm) for BACT / 10T powder.

[0203] Rim of the tank equipped with a fixed roller with a diameter of 20mm.

[0204] The first roller immersed in the fluidization tank is located 24cm from the fixed roller at the tank inlet.

[0205] The wick width is measured before and after the fanning system using a Keyence LED measuring system. An equivalent system is placed to measure the wick width at the inlet of the fluidization bath.

[0206] We obtain the following data: [Tables 1] Material Bit width (mm) Entrance to the six-bar system Six-barrel system release Fluidization tank inlet SIGRAFIL ®< T24-5.0 / 270-T140, SGL Technologies GmbH, with thermoplastic size 9-12mm 15-18mm 15-19mm

[0207] Comparative example 2: Development stage using an infrared heating system located outside the pre-impregnation system and without the presence of obstructions (E) The following procedure was carried out:

[0208] A short linear infrared heating system (single-radiant with a maximum power of 3kW with power variator) placed horizontally outside the tank.

[0209] The fiber wick passes under the module at a distance of 5cm from the transmitter.

[0210] Wicks used: SIGRAFIL ®< T24-5.0 / 270-T140 from SGL Technologies GmbH, with thermoplastic sizing. Tension of the roving at the exit of the creel and before passing under the infrared module: 500g D50 = 108 µm, (D10 = 39µm, D90 = 194µm) for BACT / 10T powder.

[0211] Rim of the tank equipped with a fixed roller with a diameter of 20mm.

[0212] The first roller immersed in the fluidization tank is located 24cm from the fixed roller at the tank inlet.

[0213] The wick width is measured before and after the IR heating system using a Keyence LED measuring system. An equivalent system is placed to measure the wick width at the fluidization bath inlet.

[0214] We obtain the following data: [Tables 2] Material Bit width (mm) Entry of the system without jams Exit from the system without jamming Fluidization tank inlet SIGRAFIL ®< T24-5.0 / 270-T140, SGL Technologies GmbH, with thermoplastic size 9-12mm 10-12mm 10-13mm Example 3 invention: Blooming step using six swages (E) with an IR heating system outside the pre-impregnation system The following procedure was carried out:

[0215] A system of 6 smooth cylindrical rollers distributed as shown in figure 7 in two rows of rollers, three being 25 mm in diameter on one row and three other rollers on another row being 20 mm in diameter.

[0216] The rollers have a Topocrom ® coating.

[0217] A short linear infrared heating system (single-radiant with a maximum power of 3 kW with a power variator) placed horizontally is placed above the slab system outside the pre-impregnation system.

[0218] The fiber strand passes through the locking system and thus under the module at a distance of 5cm from the IR transmitter.

[0219] The distance L between the two sets of upper and lower rollers is equal to 17 mm; the distance L between two adjacent rollers is equal to 15.2 mm and i = 300 µm (calculated by the equation given in figure 7 ) thus inducing a gap between the rollers of 300µm for the passage of the wick.

[0220] Rim of the tank equipped with a fixed roller with a diameter of 20mm.

[0221] Wick tension after contact with the 20mm diameter tank inlet roller and before encountering the expansion system located in the tank: 500g The width of the wick is measured before and after the expansion system using a Keyence LED measuring system. An equivalent system is placed to measure the width of the wick at the inlet of the fluidization bath.

[0222] Wicks used: SIGRAFIL ®< T24-5.0 / 270-T140 from SGL Technologies GmbH, with thermoplastic sizing.

[0223] D50 = 108 µm, (D10 = 39µm, D90 = 194µm) for BACT / 10T powder. We obtain the following data:

[0224] [Tables 3] Material Bit width (mm) Six system entry Output of the six-lock system with heating Entry into the fluidized bed locks with heating SIGRAFIL ®< T24-5.0 / 270-T140, SGL Technologies GmbH, with thermoplastic size 9-12mm 26-30mm 27-30mm Example 4 invention: Blooming step using six embarragements (E) with an IR heating system inside the impregnation system above the fluidized bed The following procedure was carried out:

[0225] A system of 6 smooth cylindrical rollers distributed as shown in figure 7 in two rows of rollers, three being 25 mm in diameter on one row and three other rollers on another row being 20 mm in diameter.

[0226] The rollers have a Topocrom ® coating.

[0227] A short linear infrared heating system (single-radiant with a maximum power of 3 kW with a power regulator) placed horizontally is placed above the shoring system.

[0228] The fiber strand passes through the locking system and thus under the module at a distance of 5cm from the IR transmitter.

[0229] The associated roller and heating system is located in the tank.

[0230] The distance L between the two sets of upper and lower rollers is equal to 17 mm; the distance L between two adjacent rollers is equal to 15.2 mm and i = 300 µm (calculated by the equation indicated in [Math 2]) thus inducing a gap between the rollers of 300 µm for the passage of the wick.

[0231] Rim of the tank equipped with a fixed roller with a diameter of 20mm.

[0232] Wick tension after contact with the 20mm diameter tank inlet roller and before meeting the expansion system located in the tank: 500g The first roller immersed in the fluidization tank is located 16cm from the last roller of the expansion system.

[0233] The wick width is measured before and after the fanning system using a Keyence LED measuring system. An equivalent system is placed to measure the wick width at the inlet of the fluidization bath.

[0234] Wicks used: SIGRAFIL ®< T24-5.0 / 270-T140 from SGL Technologies GmbH, with thermoplastic sizing.

[0235] D50 = 108 µm, (D10 = 39µm, D90 = 194µm) for BACT / 10T powder. We obtain the following data:

[0236] [Tables 4] Material Bit width (mm) Entrance to the six-lock system with heating Output of the six-lock system with heating Entry into the fluidized bed SIGRAFIL ®< T24-5.0 / 270-T140, SGL Technologies GmbH, with thermoplastic size 9-12mm 26-30mm 27-30mm

Claims

1. Method for manufacturing an impregnated fibrous material comprising a fibrous material made of continuous fibres and at least one thermoplastic polymer matrix, in which method said fibrous material is sized by a sizing thermoplastic polymer and has, before its pre-impregnation with said thermoplastic polymer, an initial width l, said method comprising a step of spreading said fibrous material before a pre-impregnation step, said spreading step being carried out by means of at least two tension devices (E) and at least one heating system SC for heating said tension devices and / or said fibrous material, said spreading, after said fibrous material has passed in contact with said tension devices, being between 1.5 and 5 times the initial width l, the spreading being consistent and always representing 1.5 to 5 times the initial width 1 when said fibrous material is placed in contact with said thermoplastic polymer matrix in the pre-impregnation system, the method being characterized in that said spread material is cooled below the Tg of the sizing thermoplastic polymer by means of a cooling system before it is placed in contact with said thermoplastic polymer matrix in the pre-impregnation system to carry out the pre-impregnation step.

2. Method according to Claim 1, characterized in that the heating system SC and the at least two tension devices (E) are located outside or inside the pre-impregnation system.

3. Method according to Claim 1 or 2, characterized in that the heating system SC and the at least two tension devices (E) are located outside the pre-impregnation system and said pre-impregnation step is carried out with a system chosen from among a fluidized bed, spraying through a nozzle, aqueous dispersion and the molten route, in particular at high speed, in particular pre-impregnation is carried out in a fluidized bed.

4. Method according to Claim 1 or 2, characterized in that the heating system SC and the at least two tension devices (E) are located inside the pre-impregnation system and said pre-impregnation step is carried out with a system chosen from among a fluidized bed, spraying through a nozzle and aqueous dispersion, in particular pre-impregnation is carried out in a fluidized bed.

5. Method according to one of Claims 1 to 4, characterized in that said at least two tension devices (E) conduct heat and a heating means SC is present and integrated in said at least two tension devices (E).

6. Method according to one of Claims 1 to 4, characterized in that said at least two tension devices (E) conduct heat and a heating means SC is present above said at least two tension devices (E) for heating the fibrous material and said at least two tension devices (E).

7. Method according to Claim 5 or 6, characterized in that said at least two tension devices (E) conduct heat and a heating means SC1 is present and integrated in said at least two tension devices (E) and a heating means SC2 is present above said at least two tension devices (E) for heating the fibrous material and said at least two tension devices (E).

8. Method according to one of Claims 1 to 4, characterized in that said at least two tension devices (E) do not conduct heat and a heating means SC2 is present above said at least two tension devices (E) for heating the fibrous material.

9. Method according to one of Claims 1 to 8, characterized in that the at least two tension devices (E) are compression rollers of convex, concave or cylindrical shape, preferably cylindrical.

10. Method according to Claim 9, characterized in that the number of rollers in contact with said fibrous material ranges from 2 to 20, in particular from 2 to 12, in particular from 2 to 9, preferably from 6 to 9.

11. Method according to either of Claims 9 and 10, characterized in that said compression rollers have a surface treatment and / or an apparent surface roughness minimizing friction with the reinforcing fibres.

12. Method according to one of Claims 9 to 11, characterized in that said rollers are separated from one another by a distance of less than 30 cm, in particular between D / 2+1 mm and 30 cm, D being the diameter of the roller.

13. Method according to one of Claims 9 to 12, characterized in that the distance between the last roller and a point of contact between the reinforcing fibre and an element of the subsequent method is less than 30 cm.

14. Method according to one of Claims 1 to 12, characterized in that said thermoplastic polymer is a non-reactive thermoplastic polymer.

15. Method according to one of Claims 1 to 14, characterized in that said at least one thermoplastic polymer of the matrix is selected from: poly(aryl ether ketone)s (PAEKs), in particular poly(ether ether ketone) (PEEK); poly(aryl ether ketone ketone)s (PAEKKs), in particular poly(ether ketone ketone) (PEKK); aromatic polyetherimides (PEIs); polyaryl sulphones, in particular polyphenylene sulphones (PPSUs); polyaryl sulphides, in particular polyphenylene sulphides (PPSs); polyamides (PAs), in particular semiaromatic polyamides (polyphthalamides) optionally modified by urea moieties; PEBAs, polyacrylates, in particular polymethyl methacrylate (PMMA); polyolefins, in particular polypropylene, polylactic acid (PLA), polyvinyl alcohol (PVA), and fluoropolymers, in particular polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE) or polychlorotrifluoroethylene (PCTFE); and blends thereof, especially a blend of PEKK and PEI, preferably from 90-10% by weight to 60-40% by weight, in particular from 90-10% by weight to 70-30% by weight.

16. Use of the method as defined in one of Claims 1 to 15, for the manufacture of calibrated tapes suitable for the manufacture of three-dimensional composite parts, by automated layup of said tapes using a robot.

17. Use according to Claim 16, characterized in that said composite parts relate to the fields of transport, in particular motor vehicle transport, of oil and gas, in particular offshore, of hydrogen, of gas storage, in particular hydrogen, and to the aeronautical, nautical and railroad transport fields; of renewable energy, in particular wind turbine or marine turbine, energy storage devices, solar panels; thermal protection panels; sports and leisure, health and medical, and electronics.