Method for producing a fibrous material made from continuous fibers and impregnated with a thermoplastic polymer

Abstract

Impregnation of a fibrous material made from continuous fibers with a thermoplastic polymer matrix, the fibrous material comprising a thermoplastic sizing polymer and having an initial width prior to impregnation. The method includes a stretching step carried out by at least two tensioning members (E) and a heating system SC for heating the tensioning members and / or the fibrous material, the stretching being 1.5 to 5 times the initial width. The stretched fibrous material is cooled by a cooling system below the Tg of the thermoplastic sizing polymer prior to contacting with the thermoplastic polymer matrix.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a fibrous material made from continuous fibers and impregnated with a thermoplastic polymer.

[0002] More particularly, the present invention relates to a method for producing an impregnated fibrous material comprising a fibrous material made from continuous fibres and at least one thermoplastic polymer matrix, said fibrous material being sized with at least one sizing thermoplastic polymer and having an initial width l before its pre-impregnation with said thermoplastic polymer, the method comprising a step of spreading said fibrous material before the pre-impregnation step. The present invention also relates to the use of said method for the production of three-dimensional composite parts and for the production of calibration tapes suitable for composite parts as such. [Background technology]

[0003] In this document, the expression "fibrous material" is understood to mean an assembly of reinforcing fibers. Before shaping, said fibrous material is in the form of a roving. After shaping, it is in the form of a tape, strip or sheet. Such an assembly constitutes a unidirectional reinforcement or a fabric or nonwoven fabric (NCF).

[0004] In this specification, the term "strip" is used to denote a strip of fibrous material having a width of 400 mm or more. The term "tape" is used to denote a tape having a calibrated width of 400 mm or less.

[0005] The quality of impregnation of continuous reinforcing fibers with thermoplastic polymer, especially high viscosity, to produce thermoplastic pre-impregnated tapes requires perfect control of the amount of impregnating polymer and the distribution quality of this polymer within the roving of continuous reinforcing fibers during the impregnation process.

[0006] Document EP 1 172 191 describes a composite part comprising a size and a thermoplastic resin matrix, as well as a method for producing said part.

[0007] Document US Pat. No. 5,895,622 also describes a composite part comprising a size and a thermoplastic resin matrix, as well as a method for manufacturing said part.

[0008] Document EP 3170638 also describes a composite part comprising a size and a thermoplastic resin matrix, as well as a method for manufacturing said part.

[0009] Many prior art patent applications, such as WO 2018 / 229114, WO 2018 / 234436, WO 2018 / 234439, and EP 2788408, describe fiber spreading as an essential parameter for obtaining uniform quality polymer impregnation within the fibers on the final tape. In particular, with reference to conventional impregnation processes, such as aqueous or solvent-based dispersions of powders, but also in particular to pre-impregnation in a fluidized bed of powders, it is essential to have a high degree of spreading of the fiber roving during the polymer carrying-off step, i.e., immersion in the pre-impregnation tank. This spreading is not only important, but must also be uniform across the width of the fiber roving and consistent over time in the pre-impregnation tank to ensure good quality of the final tape and good consistency of impregnation.

[0010] Generally, the spreading of reinforcing fibers, such as carbon fibers, is produced by mechanical, pneumatic and / or vibration systems. The main drawback of these methods is that they can cause misalignment of the fibers within the roving (blowout or suction spreading) and / or mechanical damage to the fibers by applying too high a transverse stress.

[0011] The use of these conventional systems is generally insufficient to maintain sufficient, sufficiently uniform, and consistent spreading, especially for sized fibers. This is particularly the case for fibers having thermoplastic resin sizes. This is because such thermoplastic resin sizes are often dense and elastic, and therefore only tolerate small deformations under external stress. Furthermore, because the size acts as a binder between the filaments of the fiber roving at room temperature, it is very difficult to achieve good spreading of rovings having this type of size. Therefore, the spreading produced by this type of conventional system on thermoplastic resin-sized fiber rovings is insufficient, not uniform across the width of the fiber roving, short-lived, and difficult to maintain. Therefore, it is inconsistent over time.

[0012] This spreading must be generated as close as possible to the pre-impregnation tank to be advantageous, and must, however, be maintained at a certain level during this pre-impregnation step without mechanically damaging the fibers or dislocating the fibers within the roving. Furthermore, currently used systems are generally bulky and / or not suited to the working conditions and environment (powders, solvents, water, temperature, etc.). Therefore, they cannot be as close as possible to, or even inside, the pre-impregnation system. Summary of the Invention

[0013] Therefore, there is a need for a method that allows avoiding the above-mentioned problems.

[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 resin polymer matrix, the fibrous material being sized by a sizing thermoplastic resin polymer and having an initial width 1 before its pre-impregnation with said thermoplastic resin polymer, the method comprising a step of stretching the fibrous material before the pre-impregnation step, the stretching step being carried out by at least two tensioning devices (E) and at least one heating system SC for heating the tensioning devices and / or the fibrous material, the stretching being 1.5 to 5 times the initial width 1 after the fibrous material has passed in contact with the tensioning devices, the stretched fibrous material being cooled by a cooling system below the Tg of the sizing thermoplastic resin polymer before being placed in contact with the thermoplastic resin polymer matrix in a pre-impregnation system for carrying out a pre-impregnation step, and the stretching being consistent and always representing 1.5 to 5 times the initial width 1 when the fibrous material is placed in contact with the thermoplastic resin polymer matrix in the pre-impregnation system.

[0015] The term "sizing" denotes a surface treatment applied to fibrous materials during their manufacture, of an organic nature (such as thermosetting or thermoplastic resins).

[0016] Thus, in the context of the present invention, the fibrous material is sized with a thermoplastic resin which can be semi-crystalline (e.g., PEEK, PEKK or polyamide-based sizes) or amorphous (e.g., PEI or polyamide-based sizes).

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

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

[0019] The term "spreading" refers to the factor by which the width of a fibrous material (or roving) increases relative to the initial width l of said roving, i.e., when said roving enters the system carrying out the spreading process. Obviously, this is the average width of the roving laid flat (whether referring to the initial width or the width after spreading), determined by averaging measurements taken non-contact (laser, LED, etc.) on several spools. The initial width does not necessarily correspond to the width of the roving at the outlet of the reel 11.

[0020] The spreading step is carried out before the pre-impregnation step, which means that the spreading step is carried out either upstream of the pre-impregnation system, thus outside said system, or within the pre-impregnation system, thus inside, but before the fibrous material is placed in contact with the thermoplastic resin polymer in solid or liquid (molten or dissolved) form or in suspension.

[0021] As mentioned above, spreading is carried out on the various tensioning devices E present, located outside or inside the pre-impregnation system, by means of a heating system SC for heating either the fibrous material or said tensioning devices E, or both.

[0022] The spreading depends on the fiber material used and the various linear basis weights or headings or titrations or "tex" and / or numbers in the roving.

[0023] As the fibre material passes through contact with the tensioning device E, it is heated by the heating system, either directly by the heating system SC which is thus placed above the tensioning device, or by the tensioning device which is thus itself equipped with a heating system SC, or both.

[0024] Heating the fiber material allows the size to be softened, thus resulting in a wider spreading of the fiber material, which is maintained throughout the spreading process. The spreading obtained after passing through the last tensioning device depends on the material used, but the spreading factor after passing through the last tensioning device is 1.5 to 5 times the width of the fiber material that contacted the first tensioning device.

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

[0026] Tm is determined by differential scanning calorimetry (DSC) according to standard ISO11357-3:2013, and Tg is determined by differential scanning calorimetry (DSC) according to standard ISO11357-2:2013.

[0027] Before the spread fiber material is placed in contact with the pre-impregnation system, i.e. before the sized, heated and spread fiber material is placed in contact with the thermoplastic polymer matrix in solid or liquid (molten or dissolved) form or in suspension, in particular in solid powder form, the sized, heated and spread fiber material is cooled by a cooling system, which can be ambient air or forced air.

[0028] Cooling is carried out until the temperature of the fibrous material falls below the Tg of the sizing thermoplastic polymer, and the cooling temperature is measured using a pyrometer or thermal camera.

[0029] Therefore, the extension of the fibrous material after cooling when it is placed in contact with the thermoplastic polymer in the pre-impregnation system is always 1.5 to 5 times the initial width l of the fibrous material, and therefore the extension of the fibrous material is consistent between the end of the fibrous material passing through the tensioning device and the placement of the fibrous material in contact with the thermoplastic polymer matrix in the pre-impregnation system.

[0030] By "consistently" it is meant that spreading does not vary by more than 10% between the end of the fibrous material passing through contact with the tensioning device and the placement of the fibrous material in contact with the thermoplastic polymer matrix in the pre-impregnation system.

[0031] This spreading is also uniform across the width of the fiber roving and consistent over time in the pre-impregnation tank to ensure good quality of the final impregnated fiber material and good consistency of impregnation.

[0032] The inventors have therefore unexpectedly found that heating a fibrous material sized with a thermoplastic polymer and / or heating the tensioning device with which the sized fibrous material is in contact, on the one hand, makes it possible to stretch the fibrous material more extensively than would be possible without heating, and on the other hand, makes it possible to keep the stretching consistent and uniform during the stretching process, but also makes it possible to maintain this stretching after cooling and when the sized fibrous material is brought into contact with the thermoplastic polymer matrix.

[0033] About the tensioning device "Tensioning device (E)" means any system through which the roving can pass. The at least two tensioning devices (E) can have any shape as long as the roving can pass over them. They can be fixed or rotating (or pivoting), preferably co-rotating and / or alternatively, controlled counter-rotating.

[0034] In one embodiment, the tensioning device is in a controlled rotation, particularly such that the linear velocity (or tangential velocity) at the surface of the tensioning device is less than twice the velocity of the roving or more than twice the velocity of the roving.

[0035] This means that due to the controlled rotation, the tangential velocity at the surface of the tensioning device (E) is either equal to, greater than, or less than the velocity of the roving.

[0036] Advantageously, the linear velocity at the surface of the tensioning device (or in other words the tangential velocity) is less than twice the velocity of the roving or more than twice the velocity of the roving.

[0037] More advantageously, the linear velocity at the surface of the tensioning device (or in other words the tangential velocity) is less than twice the velocity of the roving.

[0038] In one embodiment, the tangential speed of the tensioning device is 0.5-1.5 m / min and the speed of the roving is 5-15 m / min.

[0039] The heating system is any system that emits heat or radiates radiation capable of heating the textile material and / or the tensioning device (E). Thus, the tensioning device (E) is electrically conductive or absorbs the radiation emitted by the heat when heated simultaneously with the textile material.

[0040] If only the fibrous material is heated, the tensioning device is non-thermally conductive.

[0041] "Thermally conductive tensioning device (E)" means that the tensioning device (E) is made of a material that can absorb and conduct heat and therefore can be heated.

[0042] "Non-thermally conductive tensioning device (E)" means that the tensioning device (E) is made of a material that cannot absorb and conduct heat, thus preventing said tensioning device (E) from heating up.

[0043] Said at least two tensioning devices (E) are located or contained in the environment of the heating system, ie they are not outside the heating system.

[0044] Thus, said at least two tensioning devices (E) are entirely inside the heating system, but the heating system is not necessarily above them.

[0045] Advantageously, said heating system is above said at least two tensioning devices (E).

[0046] It would not depart from the scope of the present invention if the tensioning device (E) were positioned in a furnace with a heating system, e.g., an IR heating system, but the tensioning device were not positioned directly below a heating element that heats by IR, e.g., It would not depart from the scope of the present invention if the furnace includes a convection heating mode and an IR heating system.

[0047] It would not depart from the invention if the tensioning device (E) placed in this furnace or in the environment of this furnace were equipped with independent heating means, such as resistors, for heating the tensioning device (E) independently of the radiation from the IR lamps and the natural convection of the furnace, and if, given the line speed, the polymer present in the tape or roving was still in a molten state when it came into contact with the tensioning device.

[0048] The heating system SC and the at least two tensioning devices may be located outside or inside the pre-impregnation system.

[0049] When the heating system SC and the at least two tensioning devices are inside the pre-impregnation system, they are not in contact with the thermoplastic polymer, whatever form it is in (powder, aqueous or solvent-based dispersion, or melt). Thus, the heating system SC and the at least two tensioning devices are above the fluidized bed or aqueous or solvent-based dispersion or pultrusion system (melt path).

[0050] In a first variant, the heating system SC and the at least two tensioning devices are located outside the pre-impregnation system, said pre-impregnation step being carried out at particularly high speeds using a system chosen from among a fluidized bed, a spray through a nozzle, an aqueous dispersion and a melt route, and in particular the pre-impregnation being carried out in a fluidized bed.

[0051] In another embodiment of this first variant, a single tensioning device is present below the heating system SC, thus corresponding to the first tensioning device, and the second tensioning device is a roller (40) at the inlet of the tank.

[0052] In a second variant, the heating system SC and the at least two tensioning devices are located inside the pre-impregnation system, said pre-impregnation step being carried out in a system chosen from a fluidized bed, a spray through a nozzle and an aqueous dispersion, in particular the pre-impregnation being carried out in a fluidized bed.

[0053] In another embodiment of this second variant, a single tensioning device is present below the heating system SC, thus corresponding to the second tensioning device, the first being the roller (40) at the entrance to the tank.

[0054] In one of the two above variants or in another embodiment, said at least two tensioning devices (E) are thermally conductive and heating means SC are present and integrated in said at least two tensioning devices (E).

[0055] The integrated heating means may be a resistor placed inside the tensioning device, or the tensioning device may be equipped with a double jacket allowing a heated fluid to circulate and regulate or thermostat the temperature of said tensioning device (E).

[0056] In one of the two above variants or in another embodiment, the at least two tensioning devices (E) are heat conducting and heating means SC for heating the fibre material and the at least two tensioning devices (E) are present above the at least two tensioning devices (E).

[0057] Advantageously, the heating system is chosen from among infrared lamps, UV lamps and convection heating.

[0058] In one of the two above variants or in another embodiment, the at least two tensioning devices (E) are thermally conductive, the heating means SC are present and integrated in the at least two tensioning devices (E), and the heating means SC for heating the fiber material and the at least two tensioning devices (E) are present above the at least two tensioning devices (E).

[0059] In yet another embodiment, at least one of the tensioning devices (E) can be cooled to control the temperature of the fibrous material, in particular not exceeding 200°C, so as not to impair the sizing of said fibrous material.

[0060] Cooling can be carried out by blowing in cooled air or by circulating a fluid cooled to the required temperature in at least one tensioning device provided with a double jacket.

[0061] In one of the two above variants or in another embodiment, the at least two tensioning devices (E) do not conduct heat and heating means SC for heating the fibrous material are present above the at least two tensioning devices (E).

[0062] Advantageously, the at least two tensioning devices (E) are convex, concave or cylindrical, preferably cylindrical, compression rollers.

[0063] The number of rollers that come into contact with the fibrous material is in the range of 2 to 20, particularly 2 to 12, particularly 2 to 9, and preferably 6 to 9.

[0064] Advantageously, the distance between two adjacent rollers is in the range of 50 to 2000 μm, in particular 50 to 500 μm, in particular 50 to 120 μm. This distance may or may not be the same for all tensioning devices involved, so an example of implementation could take the form of a system with 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).

[0065] Advantageously, the roller is cylindrical and has a diameter D ranging from 5 to 100 mm, in particular from 5 to 50 mm, in particular from 10 to 30 mm.

[0066] Advantageously, the last roller of the spreading system, when said roller is on the outside, or when only one roller is on the outside and the second roller is at the edge of the tank, is at a distance of no more than 30 cm from the flow tank and thus from the roller at the edge of the tank: beyond 30 cm, spreading is no longer consistent and decreases as the fibrous material enters the tank.

[0067] The distance i between two adjacent rollers with the same diameter can simply be calculated (μm): [Number 1] TIFF2023554435000002.tif11170i is expressed in μm and is always a positive number because the rollers cannot penetrate each other. L: Distance between the centers of two pairs of rollers (mm) L': Distance between adjacent rollers (mm) D: Roller diameter (mm)

[0068] This formula can be applied regardless of the number of rollers, as long as the rollers have the same diameter.

[0069] For rollers of different diameters, but where each roller in each row is at the same level and has the same diameter, the formula becomes: [Number 2] TIFF2023554435000003.tif11170D1: Diameter of the rollers in the bottom row in Figure 7 (mm) D2: Diameter of the upper row of rollers in Figure 7 (mm)

[0070] Furthermore, since the tensioning devices are located as close as possible to the pre-impregnation system, in particular as close as possible to the location where the fiber material is placed in contact with the thermoplastic resin polymer of the matrix, the fiber material is not displaced and the number of tensioning devices prevents fiber breakage.

[0071] In one embodiment, the compression rollers are co-rotating and / or counter-rotating.

[0072] In another embodiment, the compression roller is vibrating.

[0073] The compression rollers may have a surface treatment and / or apparent surface roughness that minimizes friction with the reinforcing fibers.

[0074] Therefore, frictional / tensile stresses and mechanical damage to the fibers are limited by choosing a surface treatment for the compression rollers that minimizes friction with the fibers.

[0075] The surface treatment may be Topocrom®, which is an aluminum oxide and titanium oxide deposited on the roller. These treatments may affect the apparent roughness of the compression roller and / or the "physicochemical" nature of the contact (natural lubrication).

[0076] Advantageously, said rollers are spaced apart from one another by a distance of less than 30 cm, in particular D / 2+1 mm to 30 cm, where D is the diameter of the roller.

[0077] In one embodiment, the distance between the last roller and the point of contact between the reinforcing fibers and the subsequent method element is less than 30 cm.

[0078] This distance allows for maintenance of distraction.

[0079] The height between the heating system and the tensioning device is in the range of 1 to 100 cm, preferably 2 to 30 cm, in particular 2 to 10 cm.

[0080] The heating system(s) may be horizontal systems. However, one or more heating systems may also be arranged vertically so that the roving passes vertically through the tensioning device.

[0081] About fiber materials As regards the fibres constituting the fibre material, these are in particular fibres of mineral, organic or vegetable origin, among which fibres of mineral origin, mention may be made, for example, of carbon fibres, glass fibres, silicon fibres, basalt or basalt-based fibres or silica fibres.

[0082] Among the fibres of organic origin, mention may be made of fibres based on thermoplastic or thermosetting polymers, such as semi-aromatic polyamide fibres, aramid fibres or polyolefin fibres.

[0083] Preferably, they are based on amorphous thermoplastic polymers and have a glass transition temperature Tg, if amorphous, higher than the Tg of the thermoplastic polymer or polymer blend constituting the pre-impregnated matrix, or if semi-crystalline, higher than the Tm of the thermoplastic polymer or polymer blend constituting the pre-impregnated matrix. Advantageously, they are based on semi-crystalline thermoplastic polymers and have a melting temperature Tm, if amorphous, higher than the Tg of the thermoplastic polymer or polymer blend constituting the pre-impregnated matrix, or if semi-crystalline, higher than the Tm of the thermoplastic polymer or polymer blend constituting the pre-impregnated matrix. Thus, there is no risk of the organic fibers constituting the fibrous material melting during impregnation with the thermoplastic matrix of the final composite.

[0084] Among the fibres of plant origin, mention may be made of natural fibres based on flax, hemp, lignin, bamboo, silk, especially spider silk, sisal and other cellulose fibres, especially viscose fibres, which may be used pure, treated or coated with a coating layer to facilitate adhesion and impregnation of the thermoplastic polymer matrix.

[0085] The textile material may also be a knitted or woven textile.

[0086] It may also correspond to a fiber having supporting threads.

[0087] These constituent fibers may be used alone or in admixture. Thus, organic fibers may be pre-impregnated with a thermoplastic polymer and mixed with mineral fibers to form a pre-impregnated fibrous material.

[0088] Preferably, the fibrous material consists of continuous fibers of carbon, glass or silicon carbide or mixtures thereof, in particular carbon fibers, which are used in the form of a roving or several rovings.

[0089] In impregnated materials, also known as "ready-to-use" materials, the impregnating thermoplastic polymer or polymer blend is uniformly and homogeneously distributed around the fibers. In these materials, the impregnating thermoplastic polymer must be distributed as uniformly as possible within the fibers to achieve a minimum amount of porosity, i.e., a minimum amount of voids between the fibers. Specifically, the presence of porosity in these materials can act as stress concentration points when placed under mechanical tensile stress, subsequently creating fracture initiation points in the impregnated fiber material and mechanically weakening it. Therefore, uniform distribution of the polymer or polymer blend improves the mechanical strength and homogeneity of composites formed from these impregnated fiber materials.

[0090] Thus, for a "ready to use" impregnated material, the content of fibres in said impregnated fibrous material is between 45% and 65% by volume, preferably between 50% and 60% by volume, in particular between 54% and 60% by volume.

[0091] The degree of impregnation can be measured by image analysis of the cross section of the tape (especially using a microscope or a camera or digital camera) by dividing the surface area of ​​the tape impregnated with the polymer by the total surface area of ​​the product (impregnated surface area + porous surface area). To obtain good quality images, it is preferable to coat the transversely cut tape with a standard polishing resin and polish it using standard protocols that allow the sample to be observed under a microscope with a magnification of at least 6x.

[0092] Advantageously, the porosity of said impregnated fibrous material is less than 10%, in particular less than 5%, in particular less than 2%.

[0093] It should be noted that zero porosity is difficult to achieve, so that advantageously the porosity is greater than 0% but less than the degree mentioned above.

[0094] Porosity corresponds to closed porosity and can be determined either by electron microscopy or as the relative deviation between theoretical and experimental density of the impregnated fibrous material as described in the Examples section of the present invention.

[0095] The fibers that may form part of the fibrous material composition may have different linear basis weights or units or titres or "tex" and / or may be present in different numbers in the roving. Thus, the most commonly used rovings are composed of glass fibers with a tex of 600 to 4800 and carbon fibers with a tex of 3000 (3K), 6000 (6K), 12000 (12K), 24000 (24K), 48000 (48K), 50000 (50K), or 400000 (400K). For example, carbon fibers generally have diameters close to 7 to 8 μm, while glass fibers have diameters of about 13, 15, 17, or 20 μm.

[0096] Obviously, spreading depends on the number of fibers present in the fibrous material or roving.

[0097] Thus, for 12K rovings, the spreading represents 2 to 3 times the initial width l, for 24K rovings, the spreading represents 2 to 4 times the initial width l, and for 50K rovings, the spreading represents 1.5 to 2.5 times the initial width l.

[0098] Thermoplastic resin matrix polymer Thermoplastics or thermoplastic polymers are generally understood to mean materials that are solid at room temperature, may be semi-crystalline or amorphous, soften upon increasing temperature, in particular after passing its glass transition temperature (Tg), flow at higher temperatures if amorphous, or may show appreciable melting upon passing its melting temperature (Tm), and become solid again during a decrease in temperature below its crystallization temperature (in the case of semi-crystalline polymers) or below its glass transition temperature (in the case of amorphous polymers).

[0099] Tg and Tm are determined by differential scanning calorimetry (DSC) according to standards 11357-2:2013 and 11357-3:2013, respectively.

[0100] The polymer constituting the matrix for pre-impregnating the fibrous material is advantageously a thermoplastic polymer or a blend of thermoplastic polymers, which can be ground in powder form so that it can be used in equipment such as tanks, in particular fluidized bed tanks, or in aqueous dispersions.

[0101] The device in the form of a tank, in particular a fluidized bed tank, may be open or closed.

[0102] Optionally, the thermoplastic polymer or blend of thermoplastic polymers further comprises a carbon-based filler, in particular carbon black or a carbon-based nanofiller, preferably selected from carbon-based nanofillers, in particular graphene and / or carbon nanotubes and / or carbon nanofibrils, or mixtures thereof, which make it possible to conduct electricity and heat and thus facilitate the melting of the polymer matrix when heated.

[0103] Optionally, the thermoplastic polymer comprises at least one additive selected from among catalysts, antioxidants, heat stabilizers, UV stabilizers, light stabilizers, lubricants, fillers, plasticizers, flame retardants, nucleating agents, chain extenders and dyes, electrical conductive agents, thermal conductive agents, or mixtures thereof.

[0104] Advantageously, said additives are chosen from flame retardants, electrical and thermal conductive agents.

[0105] According to another variant, the thermoplastic polymer or blend of thermoplastic polymers may also contain a liquid crystal polymer or a cyclic polybutylene terephthalate, or a mixture containing these, such as the CBT100 resin sold by Cyclics Corporation. These compounds make it possible to fluidize the polymer matrix in the molten state, in particular for better penetration into the core of the fibers. The choice of one or other of these compounds depends on the nature of the polymer or blend of thermoplastic polymers used to prepare the pre-impregnated matrix, in particular its melting temperature.

[0106] The thermoplastic polymer incorporated into the composition of the pre-impregnated matrix of the fibrous material may be chosen from: - polymers and copolymers from the family of aliphatic or cycloaliphatic polyamides (PA) or semi-aromatic PAs (also called polyphthalamides (PPA)), -PEBA, polyureas, in particular aromatic polyureas; - polymers and copolymers from the acrylic family, such as polyacrylates, more particularly polymethyl methacrylate (PMMA) or its derivatives; polymers and copolymers from the family of poly(aryl ether ketones) (PAEK), such as poly(ether ether ketones) (PEEK), or poly(aryl ether ketone ketones) (PAEKK), such as poly(ether ketone ketones) (PEKK), or derivatives thereof; -aromatic polyetherimide (PEI), polyarylsulfides, in particular polyphenylene sulfide (PPS), polyarylsulfones, in particular polyphenylene sulfone (PPSU), polyolefins, in particular polypropylene (PP), -Polylactic acid (PLA), -Polyvinyl alcohol (PVA), fluoropolymers, in particular poly(vinylidene fluoride) (PVDF) or polytetrafluoroethylene (PTFE) or polychlorotrifluoroethylene (PCTFE), and mixtures thereof.

[0107] Advantageously, when said polymer is a blend of two polymers P1 and P2, the weight proportion of polymers P1 and P2 is between 1-99% and 99-1%.

[0108] Advantageously, when said thermoplastic polymer is a blend and the pre-impregnation process uses dry powders, this blend is in the form of a powder obtained either by "dry blending" before being introduced into the pre-impregnation tank, or by "dry blending" carried out directly in the tank, or by comminution of the compounds carried out beforehand in an extruder.

[0109] Advantageously, this blend is made up of powders obtained by "dry blending" before being introduced into the tank or directly into the tank, this blend of two polymers P1 and P2 being a blend of PEKK and PEI.

[0110] Advantageously, the PEKK / PEI blend is from 90-10% to 60-40% by weight, in particular from 90-10% to 70-30% by weight.

[0111] The thermoplastic polymer may correspond to a non-reactive final polymer that impregnates the fibrous material, either after pre-impregnation or with the aid of a chain extender, during heating, in particular at the level of the tensioning device in the oven and / or during processing of the tape in the final process for producing the composite part, or to a reactive prepolymer that also impregnates the fibrous material but that is capable of reacting with itself or with another prepolymer, as functional groups at the chain ends carried by said prepolymer.

[0112] The expression "non-reactive polymer" means that the molecular weight can no longer change significantly, i.e., its number average molecular weight (Mn) changes by less than 50% when it is processed, and therefore corresponds to the final polyamide polymer in the thermoplastic resin matrix.

[0113] Conversely, the expression "reactive polymer" means that the molecular weight of said reactive polymer is changed during processing by reaction of reactive prepolymers with each other by condensation or substitution, or with chain extenders by polyaddition, to give the final polyamide polymer (non-reactive) in a thermoplastic matrix, and without elimination of volatile by-products.

[0114] According to a first possibility, the prepolymer may comprise or consist of at least one reactive prepolymer (polyamide) having, on the same chain (i.e. on the same prepolymer), two terminal functional groups X' and Y', respectively, which are co-reactive with each other by condensation, more particularly X' and Y' being amine and carboxyl or carboxyl and amine, respectively. According to a second possibility, the prepolymer may comprise or consist of at least two polyamide prepolymers, each having two terminal functional groups X' or Y', respectively, which are reactive with each other and which are each identical (identical for the same prepolymer and different between the two prepolymers), and wherein the functional group X' of one prepolymer can only react, in particular by condensation, with the functional group Y' of the other prepolymer, more particularly X' and Y' being amine and carboxyl or carboxyl and amine, respectively.

[0115] According to a third possibility, said prepolymer may comprise or consist of at least one prepolymer of said thermoplastic polyamide polymer having n reactive end functional groups X chosen from -NH2, -CO2H and OH, preferably NH2 and CO2H, where n is between 1 and 3, preferably between 1 and 2, more preferentially 1 or 2, more particularly 2, and at least one chain extender Y-A'-Y, where A' is a hydrocarbon biradical and has two identical reactive end functional groups Y which are reactive by polyaddition with at least one functional group X of said prepolymer a1), and which preferably have a molecular weight of less than 500, more preferentially less than 400.

[0116] The number average molecular weight Mn of said final polymer of the thermoplastic matrix is ​​preferably in the range extending from 10 000 to 40 000, preferably from 12 000 to 30 000. These Mn values ​​are determined in m-cresol according to standard ISO 307:2007, but by changing the solvent (using m-cresol instead of sulfuric acid and at a temperature of 20°C) an intrinsic viscosity of 0.8 or more can be achieved.

[0117] The reactive prepolymers according to the two options mentioned above have a number average molecular weight Mn in the range of 500-10,000, preferably 1,000-6,800, in particular 2,500-6,800.

[0118] The Mn is determined in particular by calculation based on the content of terminal functional groups determined by potentiometric titration in solution and the functionality of the prepolymer. The weight Mn can also be determined by size exclusion chromatography or NMR.

[0119] The nomenclature used to define polyamides is set out in standard ISO 1874-1:2011 "Plastics - Polyamide (PA) moulded and extruded materials - Part 1: Nomenclature", in particular page 3 (Tables 1 and 2) and is well known to those skilled in the art.

[0120] The polyamide may be a homopolyamide or a copolyamide or a blend thereof.

[0121] Advantageously, the prepolymers constituting the matrix are chosen from polyamides (PA), in particular aliphatic, cycloaliphatic and semi-aromatic polyamides (polyphthalamides), optionally modified with urea moieties, and copolymers thereof, polymethyl methacrylate (PPMA) and copolymers thereof, polyetherimide (PEI), polyphenylene sulfide (PPS), polyphenylene sulfone (PPSU), PVDF, poly(ether ketone ketone) (PEKK), poly(ether ether ketone) (PEEK), fluoropolymers such as poly(vinylidene fluoride) (PVDF).

[0122] For the fluoropolymer, it is possible to use a homopolymer of vinylidene fluoride (VDF, formula CH₂=CF₂) or a copolymer of VDF containing at least 50% by weight of VDF and at least one other monomer copolymerizable with VDF. The VDF content must exceed 80% by weight, or even be as high as 90% by weight, to ensure good mechanical strength and chemical resistance of the structural parts, especially when subjected to thermal and chemical stress. The comonomer may be a fluoromonomer, such as vinyl fluoride.

[0123] For structural parts that must withstand high temperatures, besides fluoropolymers, PAEKs (polyaryletherketones) such as poly(etherketone) (PEK), poly(etheretherketone) (PEEK), poly(etherketoneketone) (PEKK), poly(etherketoneetherketoneketone) (PEKEKK) or PAs with high glass transition temperatures Tg are advantageously used in accordance with the invention.

[0124] Advantageously, the thermoplastic polymer is a polymer having a glass transition temperature such that Tg≧80°C, in particular ≧100°C, in particular ≧120°C, in particular ≧140°C, or a semi-crystalline polymer having a melting temperature Tm≧150°C.

[0125] Advantageously, said thermoplastic polymer of the matrix is ​​a non-reactive thermoplastic polymer.

[0126] Advantageously, said at least one thermoplastic prepolymer is chosen from polyamide, PEKK, PEI, and blends of PEKK and PEI.

[0127] Advantageously, said polyamide is chosen from aliphatic polyamides, cycloaliphatic polyamides and semi-aromatic polyamides (polyphthalamides).

[0128] Advantageously, the aliphatic polyamide prepolymer comprises: selected 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 blends thereof or copolyamides thereof, and block copolymers, in particular polyamide / polyether (PEBA), the semi-aromatic polyamides containing a urea moiety, in particular PAMXD6 and PAM, as described in EP 1 505 099 B1; semi-aromatic polyamides optionally modified with XD10 or semi-aromatic polyamides of formula X / YAr, in particular semi-aromatic polyamides of formula A / XT, in which A is selected from moieties derived from amino acids, moieties derived from lactams and moieties corresponding to the formula (Ca diamine).(Cb diacid), a represents the number of carbon atoms of the diamine and b represents the number of carbon atoms of the diacid, a and b are each 4 to 36, advantageously 9 to 18, and the (Ca diamine) moiety is selected from linear or branched aliphatic diamines, cycloaliphatic diamines and alkylaromatic diamines, and the (Cb diacid) moiety is selected from linear or branched aliphatic diacids, cycloaliphatic diacids and aromatic diacids; XT represents the moiety resulting from the polycondensation of Cx diamines with terephthalic acid, x representing the number of carbon atoms in the Cx diamine, x being 6 to 36, advantageously 9 to 18, in particular polyamides of the formula A / 6T, A / 9T, A / 10T or A / 11T, where A is as defined above, in particular the polyamides PA 6 / 6T, PA 66 / 6T, PA 6I / 6T, PA MPMDT / 6T, PA PA11 / 10T, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA BACT / 10T / 11, PA BACT / 6T / 11.

[0129] T corresponds to terephthalic acid, MXD corresponds to m-xylylenediamine, MPMD corresponds to methylpentamethylenediamine, and BAC corresponds to bis(aminomethyl)cyclohexane.

[0130] Advantageously, the thermoplastic polymer is a semi-aromatic polyamide.

[0131] Advantageously, the thermoplastic polymer is a semi-aromatic polyamide selected from PA MPMDT / 6T, PA PA11 / 10T, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA BACT / 10T / 11, PA BACT / 6T / 11.

[0132] Pre-impregnation process: Such a pre-impregnation step can be carried out according to techniques well known to those skilled in the art, in particular selected from those mentioned above.

[0133] In one advantageous embodiment, the pre-impregnation step is carried out at particularly high speeds using a system chosen from among a fluidized bed, spraying via a nozzle and melt passage, and in particular the impregnation is carried out in a fluidized bed.

[0134] Advantageously, the pre-impregnation is carried out using a system chosen from a fluidized bed, a spray via a nozzle and a melt route, in particular at high speed, and in particular the impregnation is carried out in a fluidized bed, one or more tensioning devices (E'') being present upstream of said system.

[0135] It should be noted that tensioning devices (E) and (E'') may be identical or different in terms of material or shape and their properties (diameter, length, width, height, etc., depending on the shape).

[0136] They can be at the same level or at different levels, this latter case being shown for example in FIG.

[0137] A fluidized bed pre-impregnation process is described in WO 2018 / 115736.

[0138] Advantageously, the pre-impregnation step is carried out in a fluidized bed.

[0139] An example of a unit for implementing a manufacturing method without a heating step by means of at least one tensioning device is described in WO 2015 / 121583.

[0140] This system describes the use of a tank equipped with a fluidized bed for carrying out a pre-impregnation step and can be used within the context of the present invention.

[0141] Advantageously, the tank with the fluidized bed is provided with at least one tensioning device (E'), which may be a compression roller.

[0142] It should be noted that tensioning devices (E) and (E') may be identical or different in terms of material or shape and their properties (diameter, length, width, height, etc. depending on the shape).

[0143] However, the tensioning device (E') is not a heating device and is not heated.

[0144] The process of pre-impregnation of the fibrous material is carried out by passing one or more rovings through a continuous pre-impregnation device comprising a tank (10) equipped with at least one tensioning device (E') and containing a fluidized bed (12) of powder of said polymer matrix.

[0145] The polymer matrix or polymer powder is introduced into the tank and suspended in a gas G (e.g., air) which flows into the tank (10) through a hopper (11). The rovings are circulated through this fluidized bed (12).

[0146] The tank may have any shape, in particular a cylinder or parallelepiped, in particular a rectangular prism or cube, advantageously a rectangular prism.

[0147] The tank (10) can be an open or closed tank, but is advantageously an open tank.

[0148] If the tank is closed, it is equipped with a sealing system so that the polymer matrix powder cannot leave the tank.

[0149] This pre-impregnation step is therefore carried out by the dry route, i.e. the thermoplastic polymer matrix is ​​in powder form and is in particular suspended in a gas, in particular air, but cannot be suspended in a dispersion, in a solvent or in water.

[0150] Each pre-impregnated roving after passing through the tensioning device (E) enters the fluidized bed.

[0151] The fiber roving or parallel fiber roving then passes into and out of a tank (10) equipped with a fluidized bed (12) fitted with at least one tensioning device (E'), which is in particular a compression roller or is already present in the tank, and then enters the fluidized bed (12) fitted with at least one tensioning device (E').

[0152] The fiber roving or parallel fiber roving then emerges from the tank after pre-impregnation after optional control of its residence time in the powder.

[0153] The process of pre-impregnation by spraying through a nozzle is described in WO 2018 / 115739.

[0154] The process of pre-impregnation by the melt route is described in WO 2018 / 234439.

[0155] Advantageously, the pre-impregnation step is carried out by the melt route, in particular by drawing.

[0156] Melt pre-impregnation techniques are well known to those skilled in the art and are described in the references listed above.

[0157] The pre-impregnation step is carried out in particular by crosshead extrusion of the polymer matrix and the passage of said roving or said rovings through this crosshead and then through a heated die, which may be equipped with a fixed or rotating tensioning device through which the rovings pass, thus causing the spreading of said rovings and allowing their pre-impregnation.

[0158] Pre-impregnation also differs from that described in US Patent Application Publication No. 2014 / 0005331 in that resin is supplied to both sides of the roving and there is no contact surface on one of the two surfaces to remove some of the resin.

[0159] Advantageously, the pre-impregnation step is carried out by a melt path at high speed, ie by passing said roving at a speed of at least 5 m / min, in particular above 9 m / min.

[0160] In one embodiment, the method according to the invention comprises the step of heating the pre-impregnated fibrous material to melt the matrix thermoplastic polymer and complete the impregnation of said fibrous material.

[0161] In another embodiment, the method according to the invention comprises the step of heating the pre-impregnated fibrous material to melt and polymerize the thermoplastic resin prepolymer of the matrix, optionally together with said extender, to complete the impregnation of said fibrous material.

[0162] The heating step can be carried out as described in WO 2018 / 234439.

[0163] Whatever the system chosen to carry out the pre-impregnation step, in particular using a system chosen from among fluidized bed, spraying via nozzles and melt route, in particular at high speeds, in particular in a fluidized bed, the pre-impregnation step may be immediately followed by the first heating step, or other steps may be carried out between the pre-impregnation step and the heating step.

[0164] Advantageously, said first heating step immediately follows a pre-impregnation step, the expression "immediately following" meaning that there is no intermediate step between the pre-impregnation step and said heating step.

[0165] Advantageously, a single heating step is carried out immediately after the pre-impregnation step.

[0166] Advantageously, said at least one heating system is chosen from infrared lamps, UV lamps and convection heating.

[0167] The textile material is in contact with a tensioning device in the heating system, which is electrically conductive, so that the heating system is also electrically conductive.

[0168] Advantageously, said at least one heating system is chosen from infrared lamps.

[0169] Advantageously, said at least one tensioning device (E'') is a convex, concave or cylindrical compression roller.

[0170] It should be noted that the compression rollers corresponding to the tensioning devices (E), (E') and (E'') may be identical or different in terms of material or shape and their properties (diameter, length, width, height, etc., depending on the shape).

[0171] A convex shape favors spreading, whereas a concave shape is unfavorable to spreading, but is performed nonetheless.

[0172] The at least one tensioning device (E'') may also have an alternating convex and concave shape, so that when the roving passes over a convex compression roller, it spreads out, and then when it passes over a concave compression roller, it contracts, etc., making it possible to improve the uniformity of the impregnation, in particular of the core, if necessary.

[0173] The expression "compression roller" means that the passing roving presses partially or completely against the surface of said compression roller, which induces spreading of said roving.

[0174] The rollers may be free (rotating) or fixed.

[0175] They may be smooth, ribbed, or grooved.

[0176] Advantageously, the roller is cylindrical and ribbed. When the roller is ribbed, two ribs may be present starting from the center of said roller and in opposite directions, thus moving the rovings away from each other towards the outside of the roller, or may start from the outside of said roller and move in opposite directions, thus making it possible to bring the rovings towards the center of the roller.

[0177] This heating step allows the pre-impregnation to be uniform and thus complete, thus impregnating the core and having a high fiber volume content, particularly consistent over at least 70% of the volume of the strip or tape, particularly over at least 80% of the volume of the strip or tape, particularly over at least 90% of the volume of the strip or tape, more particularly over at least 95% of the volume of the strip or tape, and also reduces porosity.

[0178] The elongation depends on the fiber material used, for example the elongation of carbon fiber material is much greater than that of flax fiber.

[0179] Spreading also depends on the number of fibers in the roving, their average diameter, and their degree of aggregation by size.

[0180] The diameter of the at least one compression roller (tensioning device (E'')) is between 3 mm and 100 mm, preferably between 3 mm and 20 mm, in particular between 5 mm and 10 mm.

[0181] Below 3 mm, the deformation of the fibers induced by the compression rollers is too great.

[0182] Advantageously, the compression roller is cylindrical, grooveless and in particular made of metal.

[0183] Advantageously, said at least one tensioning device (E'') consists of at least one compression roller of cylindrical shape.

[0184] Advantageously, said at least one tensioning device (E'') consists of 1 to 15 compression rollers (R1 to R15), preferably 3 to 15 compression rollers (R3 to R15), in particular 6 to 10 compression rollers (R6 to R10), of cylindrical shape.

[0185] Obviously, regardless of the number of tensioning devices (E'') present, they are all located or contained within the environment of the heating system, i.e. they are not outside the heating system.

[0186] According to another aspect, the invention relates to the use of the method defined above for the manufacture of a calibration tape suitable for the manufacture of three-dimensional composite parts by automated lay-up of said tape using a robot.

[0187] In another embodiment, the composite part relates to the fields of transportation, in particular motor transport, oil and gas, in particular offshore, hydrogen, gas storage, in particular hydrogen, aviation, maritime and rail transport; renewable energy, in particular wind or marine turbines, energy storage devices, solar panels; thermal protection panels; sport and leisure, health and medicine, and electronics.

[0188] According to another aspect, the invention relates to a three-dimensional composite part, characterized in that it results from the use of the method defined above. [Brief explanation of the drawings]

[0189] [Figure 1]This is a partial view of a unit for implementing the method for producing pre-impregnated fiber material according to WO 2018 / 115736. Each roving to be impregnated is unwound from the device 10 using a reel 11 under tension generated by a roll (not shown). The device 10 includes multiple reels 11, each of which allows one roving to be unwound. Thus, several fiber rovings can be impregnated simultaneously. Each reel 11 is provided with a brake (not shown) to apply tension to each fiber roving. In this case, an alignment module 12 allows the fiber rovings to be arranged parallel to one another. In this way, the fiber rovings cannot come into contact with each other, which in particular prevents mechanical damage to the fibers. The fiber rovings or parallel fiber rovings then enter a tank 20 equipped with at least one tensioning device (E') (23), in particular a fluidized bed 22 equipped with compression rollers. Polymer powder is introduced into the tank and suspended in gas G (e.g., air) that flows into the tank through a hopper 21. The rovings are circulated through this fluidized bed 22 . [Figure 2] FIG. 1 shows a tank with a fluidized bed provided with at least one tensioning device (E′), which may be a compression roller. [Figure 3] 1 shows a fluidized bed tank equipped with a tensioning device (E') through which the stretched and heated fiber material circulates to perform pre-impregnation, the stretching process being carried out outside the impregnation system, and the heating system SC (30) is integrated into the compression rollers (E). The fiber material enters and leaves the tank by passing over the tank edge (40), which may be a fixed or movable roller. Although the figure shows two rollers, the invention is not limited to this configuration. [Figure 4]1 shows a fluidized bed tank equipped with a tensioning device (E') through which the stretched and heated fiber material circulates to perform pre-impregnation, the stretching process being carried out outside the impregnation system, and a heating system SC (30), which may be an infrared system, is located above the compression rollers (E). The fiber material enters and leaves the tank by passing over the tank edge (40), which may be a fixed or movable roller. Although the figure shows two rollers, the invention is not limited to this configuration. [Figure 5] 1 shows a fluidized bed tank equipped with a tensioning device (E') through which the stretched and heated fiber material circulates to perform pre-impregnation; the stretching process is carried out inside the impregnation system, and the heating system SC (30) is integrated into the compression roller (E) located above the fluidized bed. The fiber material enters and leaves the tank by passing over the tank edge (40), which may be a fixed or movable roller. Although the figure shows two rollers, the invention is not limited to this configuration. [Figure 6] 1 shows a fluidized bed tank equipped with a tensioning device (E') through which the stretched and heated fiber material circulates to perform pre-impregnation. The stretching process is carried out inside the impregnation system, and a heating system SC (30), which may be an infrared system, is located above a compression roller (E) located above the fluidized bed. The fiber material enters and leaves the tank by passing over the tank edge (40), which may be a fixed or movable roller. Although the figure shows two rollers, the invention is not limited to this configuration. [Figure 7] FIG. 1 shows a system of six compression rollers (E) on two levels. [Example]

[0190] Comparative Example 1: Spreading process without a heating system and using six tensioning devices (E) located outside the pre-impregnation system The following steps were performed: As shown in Figure 7, it is a system of six smooth cylindrical rollers distributed in two rows of rollers, three in one row with a diameter of 25 mm and three in the other row with a diameter of 20 mm.

[0191] The roller has a Topocrom® coating.

[0192] The roller system is located outside the tank.

[0193] The distance L between the two pairs of upper and lower rollers is equal to 17 mm, and the distance L' between two adjacent rollers is equal to 15.2 mm, with i = 300 μm (calculated by the formula shown in Figure 7), thus inducing a gap between the rollers of 300 μm for the passage of the roving.

[0194] Roving used: SIGRAFIL® T24-5.0 / 270-T140 from SGL Technologies GmbH with thermoplastic size.

[0195] Tension of the roving before it exits the creel and encounters the spreading system: 500g

[0196] For BACT / 10T powder, D50=108 μm, (D10=39 μm, D90=194 μm).

[0197] The edge of the tank is equipped with fixed rollers with a diameter of 20 mm.

[0198] The first roller, immersed in the flow tank, is located 24 cm from the fixed roller at the tank inlet.

[0199] The width of the roving before and after the spreading system is measured using a Keyence LED measuring system. An equivalent system is positioned to measure the width of the roving at the inlet of the fluidized bath.

[0200] The data obtained is as follows: [Table 1] TIFF2023554435000004.tif45170

[0201] Comparative Example 2: Spreading process using an infrared heating system located outside the pre-impregnation system and without a tensioning device (E) The following steps were performed: A linear shortwave infrared heating system (single radiator with a maximum power of 3 kW with a power variator) is positioned horizontally on the outside of the tank.

[0202] The fiber roving passes under the module at a distance of 5 cm from the emitter.

[0203] Roving used: SIGRAFIL® T24-5.0 / 270-T140 from SGL Technologies GmbH with thermoplastic size.

[0204] Tension of the roving before it exits the creel and passes under the infrared module: 500g

[0205] For BACT / 10T powder, D50=108 μm, (D10=39 μm, D90=194 μm).

[0206] The edge of the tank is equipped with fixed rollers with a diameter of 20 mm.

[0207] The first roller, immersed in the flow tank, is located 24 cm from the fixed roller at the tank inlet.

[0208] The width of the roving before and after the IR heating system is measured using a Keyence LED measuring system. An equivalent system is positioned to measure the width of the roving at the fluidized bath inlet.

[0209] The data obtained is as follows: [Table 2] TIFF2023554435000005.tif40170

[0210] Example 3 (Invention): Spreading process using six tensioning devices (E) equipped with an IR heating system outside the pre-impregnation system The following steps were performed: As shown in Figure 7, it is a system of six smooth cylindrical rollers distributed in two rows of rollers, three in one row with a diameter of 25 mm and three in the other row with a diameter of 20 mm.

[0211] The roller has a Topocrom® coating.

[0212] A horizontally arranged linear shortwave infrared heating system (single radiator with a maximum power of 3 kW equipped with a power variator) is installed above the system of tensioning devices outside the pre-impregnation system.

[0213] The fiber roving passes through a system of tensioning devices and therefore under the module at a distance of 5 cm from the IR emitter.

[0214] The distance L between the two pairs of upper and lower rollers is equal to 17 mm, and the distance L' between two adjacent rollers is equal to 15.2 mm, with i = 300 μm (calculated by the formula shown in Figure 7), thus inducing a gap between the rollers of 300 μm for the passage of the roving.

[0215] The edge of the tank is equipped with fixed rollers with a diameter of 20 mm.

[0216] Tension of the roving after contact with the tank inlet roller with a diameter of 20 mm and before encountering the spreading system located in the tank: 500 g

[0217] The width of the roving before and after the spreading system is measured using a Keyence LED measuring system. An equivalent system is positioned to measure the width of the roving at the inlet of the fluidized bath.

[0218] Roving used: SIGRAFIL® T24-5.0 / 270-T140 from SGL Technologies GmbH with thermoplastic size.

[0219] For BACT / 10T powder, D50=108 μm, (D10=39 μm, D90=194 μm).

[0220] The data obtained is as follows: [Table 3] TIFF2023554435000006.tif45170

[0221] Example 4 (Invention): Spreading process using six tensioning devices (E) equipped with IR heating systems inside the impregnation system above the fluidized bed The following steps were performed: As shown in Figure 7, it is a system of six smooth cylindrical rollers distributed in two rows of rollers, three in one row with a diameter of 25 mm and three in the other row with a diameter of 20 mm.

[0222] The roller has a Topocrom® coating.

[0223] A horizontally arranged linear shortwave infrared heating system (single radiator with a power of up to 3 kW equipped with a power variator) is installed above the system of tensioning devices.

[0224] The fiber roving passes through a system of tensioning devices and therefore under the module at a distance of 5 cm from the IR emitter.

[0225] The tensioner rollers and associated heating system are located in the tank.

[0226] The distance L between the two pairs of rollers, upper and lower, is equal to 17 mm, and the distance L' between two adjacent rollers is equal to 15.2 mm, with i = 300 μm (calculated by the formula given in [Equation 2]), thus inducing a gap between the rollers of 300 μm for the passage of the roving.

[0227] The edge of the tank is equipped with fixed rollers with a diameter of 20 mm.

[0228] Tension of the roving after contact with the tank inlet roller with a diameter of 20 mm and before encountering the spreading system located in the tank: 500 g

[0229] The first roller immersed in the flow tank is located 16 cm from the last roller of the spreading system.

[0230] The width of the roving before and after the spreading system is measured using a Keyence LED measuring system. An equivalent system is positioned to measure the width of the roving at the inlet of the fluidized bath.

[0231] Roving used: SIGRAFIL® T24-5.0 / 270-T140 from SGL Technologies GmbH with thermoplastic size.

[0232] For BACT / 10T powder, D50=108 μm, (D10=39 μm, D90=194 μm).

[0233] The data obtained is as follows: [Table 4] TIFF2023554435000007.tif45170

Claims

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

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

3. 3. The method according to claim 1 or 2, characterized in that the heating system SC and the at least two tensioning devices (E) are located outside the pre-impregnation system and that the pre-impregnation step is carried out, in particular at high speeds, with a system selected from a fluidized bed, a spray through a nozzle, an aqueous dispersion and a melt route, in particular the pre-impregnation is carried out in a fluidized bed.

4. 3. The method according to claim 1 or 2, characterized in that the heating system SC and the at least two tensioning devices (E) are located inside a pre-impregnation system, said pre-impregnation step being carried out using a system selected from a fluidized bed, a spray through a nozzle and an aqueous dispersion, in particular the pre-impregnation being carried out in a fluidized bed.

5. 5. The method according to any one of claims 1 to 4, characterized in that said at least two tensioning devices (E) are thermally conductive and heating means SC are present and integrated in said at least two tensioning devices (E).

6. 5. The method according to claim 1, characterized in that the at least two tensioning devices (E) are thermally conductive and that heating means SC for heating the fibre material and the at least two tensioning devices (E) are present above the at least two tensioning devices (E).

7. 7. The method according to claim 5 or 6, characterized in that the at least two tensioning devices (E) are heat conducting, heating means SC1 are present and integrated in the at least two tensioning devices (E) and heating means SC2 for heating the fibre material and the at least two tensioning devices (E) are present above the at least two tensioning devices (E).

8. 5. The method according to claim 1, characterized in that the at least two tensioning devices (E) do not conduct heat and that heating means SC2 for heating the fibre material are present above the at least two tensioning devices (E).

9. 9. The method according to any one of claims 1 to 8, characterized in that the at least two tensioning devices (E) are convex, concave or cylindrical, preferably cylindrical, compression rollers.

10. 10. The method according to claim 9, characterized in that the number of rollers in contact with the fibrous material is in the range from 2 to 20, in particular from 2 to 12, in particular from 2 to 9, preferably from 6 to 9.

11. 11. The method according to claim 9 or 10, characterized in that the compression rollers have a surface treatment and / or apparent surface roughness that minimizes friction with the reinforcing fibers.

12. 12. The method according to any one of claims 9 to 11, characterized in that the rollers are spaced apart from each other by a distance of less than 30 cm, in particular from D / 2+1 mm to 30 cm, where D is the diameter of the rollers.

13. 13. The method according to any one of claims 9 to 12, characterized in that the distance between the last roller and the contact point between the reinforcing fibres and the subsequent method element is less than 30 cm.

14. 14. The method according to any one of claims 1 to 13, characterized in that the thermoplastic polymer is a non-reactive thermoplastic polymer.

15. The at least one thermoplastic polymer of the matrix may be selected from the group consisting of poly(aryl ether ketones) (PAEK), in particular poly(ether ether ketones) (PEEK); poly(aryl ether ketone ketones) (PAEKK), in particular poly(ether ketone ketones) (PEKK); aromatic polyetherimides (PEI); polyarylsulfones, in particular polyphenylene sulfones (PPSU); polyarylsulfides, in particular polyphenylene sulfide (PPS); polyamides (PA), in particular semi-aromatic polyamides (polyphthalamides), optionally modified with urea moieties; PEBA, poly(phenylene sulfide); 15. The method according to claim 1, characterized in that the polymer is selected from the group consisting of triacrylates, 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, in particular blends of PEKK with PEI, preferably in an amount of 90-10% by weight to 60-40% by weight, in particular 90-10% by weight to 70-30% by weight.

16. 16. Use of the method according to any one of claims 1 to 15 for the production of a calibration tape suitable for the production of three-dimensional composite parts by automated tape lay-up using a robot.

17. 17. Use according to claim 16, characterised in that the composite part relates to the fields of transport, in particular motor transport, oil and gas, in particular offshore, hydrogen, gas storage, in particular hydrogen, aviation, maritime and rail transport; renewable energies, in particular wind or marine turbines, energy storage devices, solar panels; thermal protection panels; sports and leisure, health and medicine, and electronics.

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