FR2949792A1 - METHOD FOR MANUFACTURING THERMOPLASTIC POLYMER PRE-IMPREGNATED FIBROUS MATERIAL AND SYSTEM THEREOF - Google Patents

Abstract

The invention relates to a method of manufacturing a fibrous material such as a nonwoven fabric, felt, which may be in the form of strips, webs, braids, locks or pieces, based on reinforcing fibers and thermoplastic polymer. The invention also relates to a system for implementing the method. According to the invention at least two sets of different fibers are used, a first series of fibers comprising mineral fibers and a second series of fibers comprising thermoplastic polymer fibers having a melting temperature Tf, the two sets of fibers are available at contact one of the other then heated all of the two sets of fibers to a temperature at least equal to the melting temperature Tf of the thermoplastic fibers and then allowed to cool to room temperature. The invention applies to the manufacture of 3D parts.

Description

METHOD FOR MANUFACTURING THERMOPLASTIC POLYMER PREMIXED FIBROUS MATERIAL AND SYSTEM FOR CARRYING OUT SAID METHOD

FIELD OF THE INVENTION The present invention relates to a method for manufacturing a fibrous material, such as a nonwoven fabric, felt, which may be in the form of strips, sheets, braids, locks or pieces, based on reinforcement and thermoplastic polymer and an implementation system.

The fibers that can be used in the composition of the material are more particularly carbon fibers, glass fibers, polymer-based fibers, vegetable fibers, used alone or as a mixture. Of interest in the present invention are lightweight composite materials for the manufacture of mechanical parts having a 3-dimensional structure and having properties of good mechanical strength, thermal and able to evacuate electrostatic charges, that is to say to say properties compatible with the manufacture of parts in the field of mechanics, aeronautics and nautical. STATE OF THE ART It is known to use refractory fabrics pre-impregnated with a resin in order to produce a thermally insulating matrix so as to provide thermal protection for mechanical devices subjected to high temperatures, as may be the case in the field. aeronautics or the automobile. Reference can be made to European Patent No. 0 398 787, which describes a thermal protection layer comprising a refractory fabric intended to protect the ferrule of a ramjet engine chamber. In addition to the complexity of producing this thermal protection layer, the refractory fabric embedded in this layer only fulfills the function of heat shield. In recent years, composite fibers have also been used to manufacture, in particular, various aeronautical or automobile parts. These composite fibers, which are characterized by good thermomechanical and chemical resistance, consist of a reinforcing filament reinforcement intended to distribute the tensile, flexural or compressive tensile forces, in some cases to provide protection chemical material and give it its shape. Ref: 0277-ARK12 One can for example refer to the patent application FR 2 918 081 which describes a process for impregnating continuous fibers with a composite polymeric matrix containing a thermoplastic polymer. Methods for manufacturing composite parts from these coated fibers include various techniques such as, for example, contact molding, spray molding, autoclaved draping or low pressure molding. A technique for making hollow parts is that called filament winding, which consists in impregnating dry fibers with a resin and then winding them on a mandrel formed of reinforcements and of a shape adapted to the part to be manufactured. The piece obtained by winding is then cured by heating. Another technique for making plates or shells consists in impregnating fiber fabrics and then pressing them into a mold in order to consolidate the laminated composite obtained.

For the manufacture of polymeric material with fiber reinforcement, a sizing step is generally used, which consists in depositing a thermoplastic polymer film on fibers. Thus, the process for manufacturing preimpregnated material from Cyntex comprises, as a fiber coating step, the continuous passage of fibers in a molten bath of thermoplastic polymer containing an organic solvent such as benzophenone; this solvent makes it possible to adapt the viscosity of the melted mixture and to ensure a good coating of the fibers. The pre-impregnated fibers of polymers are then shaped (for example cut into strips and then placed under a press, for producing the structural parts, and then heated to a temperature above the melting temperature of the polymer to ensure the cohesion of the polymer. material and in particular the adhesion of the polymer to the fibers.

The technical problem Depending on the chemical nature of the polymer, the heating temperatures can rise to temperatures above 250 ° C, and even higher than 320 ° C, temperatures much higher than the boiling temperature of the solvent, resulting in a sudden departure of solvent, causing defects in the room and therefore a lack of reproducibility of the process as well as the risk of explosion endangering the operators. Ref: 0277-ARK12 Another known method of fiber sizing is the continuous passage of the fibers in an aqueous dispersion of polymeric powder and then drying the fibers to evaporate the water in an oven, followed by a heat treatment for the fusion of the polymer. This heat treatment can be done in a shaping die, especially to make strips of pre-impregnated material. These strips are then used for the manufacture of structural parts, by arrangement in a mold, a press, etc. This process requires two separate heating zones or the use of two separate furnaces is complex and difficult to implement.

As another state of the art relating to the manufacture of a fibrous material, reference may be made to document US Pat. No. 4 541884 from Imperial Chemical Industries or to document EP 0406 067 filed in the joint names of Atochem and the State. French. As prior art relating to the introduction of fibers for the formation of fibrous material and the constitution of structures based on this fibrous material, reference may be made to US Pat. No. 6,607,626; US Pat. No. 6,939,424 and US Pat. No. 7,235,149. SUMMARY OF THE INVENTION The subject of the invention is a new process for the on-line and continuous manufacture of fibrous material, making it possible to overcome the above disadvantages. The proposed method also makes it possible to obtain a homogeneous fibrous material. There can be no irregularities in the structure or node susceptible to embrittle the material with risks of rupture as is the case with the methods of the prior art. More specifically, the subject of the invention is a process for manufacturing a fibrous material pre-impregnated with a thermoplastic polymer, consisting of i) using at least two sets of different fibers, a first series of fibers comprising mineral fibers and a second series of fibers comprising thermoplastic polymer fibers having a melting temperature Tf, ii) arranging the two series of fibers in contact with each other and then iii) heating all of the two series of fibers to one another. temperature at least equal to the melting temperature Tf of the thermoplastic fibers and to allow the whole to cool to room temperature. Ref: 0277-ARK12 Advantageously, preheating is carried out during contacting of the two sets of fibers at a temperature below the melting temperature Tf, preferably at a temperature less than or equal to the glass transition temperature Tv of the fibers thermoplastic polymer, so as to mount the two series of fibers in temperature to reduce or eliminate the temperature difference caused by a distinct thermal inertia for the two sets of fibers. This thus makes it possible to improve the contact and consequently the impregnation of the fibers of the first series by the second series of fibers, during the melting of the polymer fibers.

When the two sets of fibers are heated to the melting temperature Tf, they are also shaped to obtain a homogeneous material of calibrated shape and dimensions. The introduction of the two sets of fibers and the shaping of the material impregnated with molten thermoplastic fibers are performed by a system comprising the implementation of calendering operations. Several successive calendering operations are preferably carried out in order to refine the shaping of the material and to obtain a homogeneous material without defects, that is to say without granulosity and without air bubbles. The mineral fibers may be arranged side by side or may be woven in two directions. These fibers may be of the same chemical nature or be of a different nature, for example carbon fibers woven with glass fibers. In order to improve the mechanical strength of the structure made from the appropriate arrangement of several materials (stack of several strips for example), it is expected to have on the assembly of the two sets of fibers, just before step iii ) inorganic fillers in powder form, conductive or not, such as silica, metal powder, powdery carbon black, carbon fibrils, carbon nanotubes, but also silicon carbide, carbonitride nanotubes boron, boron nitride or silicon. Preferably, the charges used are conducting electricity and / or heat, such as carbon nanotubes, carbon fibrils or even carbon black. Preferably, carbon nanotubes are used. It will be recalled that NTC carbon nanotubes are understood to mean one or more hollow tubes with one or more graphite plane walls or graphene sheets, coaxial, or graphene sheet wound on itself. This or these tubes, most often opening (that is to say open at one end) resemble several grating tubes arranged coaxially; in cross section the CNTs are in the form of concentric rings. The external diameter of the CNT is from 2 to 50 nm. We speak of single-walled carbon nanotubes (SWNTs) or multi-walled carbon nanotubes (MWNTs). The dusting of the loads can be ensured by means of a vibrating support, in order to ensure a homogeneous distribution on the fibers. For example, the CNT powder is deposited directly on the fibrous material, placed flat on a vibrating support, in order to allow the distribution of the powder on the fibers. Before the dispersion of the charges on the two sets of fibers, these fillers can be subjected to a chemical treatment in order to bring them functions, for example polar, in order to improve their adhesion to the polymeric fibers or else subjected to a heat treatment, by example greater than 900 ° C and better at 1000 ° C to remove metal impurities due to their synthesis process. Advantageously, the fillers are neither chemically nor thermally treated. The thermoplastic fibers may consist of a single type of polymer or of several polymers; in the case of several polymers, the melting temperature Tf above is that of the highest melting temperature polymer. The polymers forming part of the fibers of the second series of fibers may be chosen, without limitation, from: polyethylenimines (PEI), polyimides (PI), polyolefins such as polyethylene, especially high density polyethylene, Polypropylene and copolymers of ethylene and / or polypropylene; thermoplastic polyurethanes (TPU); polyesters such as polyhydroxyalkanoates; polyethylene terephthalates (PET) or butylene (PBT); polyphenylene sulfides (PPS);

Ref: 0277-ARK12 - polyvinyl chlorides; silicone or fluorosilicone polymers; poly (vinyl alcohol); polyarylether ketones (PAEK: PolyArylEtherKetone) such as polyetheretherketone (PEEK) and polyetherketoneketone (PEKK); polyamides such as polyamide such as polyamide 6 (PA-6), polyamide 11 (PA-11), polyamide 12 (PA-12), polyamide 6.6 (PA-6.6), polyamide 4.6 (PA-6), 4.6), polyamide 6.10 (PA-6.10), polyamide 6.12 (PA-6.12), aromatic polyamides, in particular polyphthalamides and aramid, and block copolymers, in particular polyamide / polyether; the fluorinated polymers comprising at least one monomer of formula (I): CFX = CHX '(I) where X and X' independently denote a hydrogen or halogen atom (in particular fluorine or chlorine) or a radical perhalogenated (in particular perfluorinated) alkyl, and preferably X = F and X '= H, such as polyvinylidene fluoride (PVDF), preferably in the α form, vinylidene fluoride copolymers with, for example, hexafluoropropylene (HFP), fluoroethylene / propylene copolymers (FEP), copolymers of ethylene with either fluoroethylene / propylene (FEP), tetrafluoroethylene (TFE), perfluoromethylvinyl ether (PMVE) or chlorotrifluoroethylene (CTFE) , some of these polymers being in particular marketed by ARKEMA under the name Kynar; and - their mixture.

For the fluoropolymers, it is preferred to use a homopolymer of vinylidene fluoride (VDF of formula CH2 = CF2) or copolymer of VDF comprising by weight at least 50% by weight of VDF and at least one other monomer copolymerizable with VDF. The VDF content must be greater than 80% by weight, or even better 90% by weight, to ensure good mechanical strength to the structural part, especially when subjected to thermal stresses. The comonomer may be a fluorinated monomer chosen, for example, from vinyl fluoride; trifluoroethylene (VF3); the

Ref: 0277-ARK12 chlorotrifluoroethylene (CTFE); 1,2-difluoroethylene; tetrafluoroethylene (TFE); ethylene tetrafluoroethylene (ETFE), hexafluoropropylene (HFP); perfluoro (alkyl vinyl) ethers such as perfluoro (methyl vinyl) ether (PMVE), perfluoro (ethyl vinyl) ether (PEVE) and perfluoro (propyl vinyl) ether (PPVE); perfluoro (1,3-dioxole); perfluoro (2,2-dimethyl-1,3-dioxole) (PDD). Preferably, the optional comonomer is chosen from chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), trifluoroethylene (VF3) and tetrafluoroethylene (TFE). The comonomer may also be an olefin such as ethylene or propylene. The preferred comonomer is HFP.

For structural parts that must withstand high temperatures, in addition to the fluorinated polymers, PAEK (PolyArylEtherKetone) such as PEK, PEEK, PEKK, PEKEKK, etc. are advantageously used according to the invention. Compared to the processes of the prior art, the process according to the present invention is perfectly well suited to polymers having high melting temperatures, for example greater than 130 ° C, such as fluoropolymers, PAEKs, high density polyethylenes. , or else PET or PBT or PBT. It is also possible to use Kevlar fibers or aramid fibers.

The mineral fibers to which the invention applies are in particular the fibers of carbon, glass, boron, silica, natural fibers such as flax, especially silk spider, hemp, sisal. These fibers can be used pure, treated or coated with an induction layer, in order to facilitate the adhesion / impregnation of the thermoplastic polymer fibers of the second series or their handling before impregnation by melting of this polymer. Organic fibers may be blended with the mineral fibers to form the first series of fibers which is to be impregnated with polymer after the melting of the thermoplastic polymer fibers of the second series. In this case we will choose of course organic fibers that is to say polymer fibers whose melting temperature is higher than the melting temperature Tf fibers of the second series that one melts. Thus, there is no risk of fusion for the organic fibers present in the first series of fibers.

Ref: 0277-ARK12 The fibrous material made with the process is advantageously obtained with 50% mineral fibers and 50% thermoplastic polymer fibers, preferably with 30% mineral fibers and 70% thermoplastic polymer fibers.

The invention also relates to the use of fibrous material as described for the manufacture of mechanical parts in 3D, in particular the wings of an airplane, the fuselage of an airplane, the hull of a boat, the spars or spoilers of an automobile, or brake discs, or the cylinder body or steering wheels.

The invention also relates to a system for implementing the method, this system comprising a device for placing fibers in such a way as to arrange the two series of fibers in contact with each other, and a device for heating the fibers. two sets of fibers. According to the invention, the heating of the two sets of mineral fibers and of polymer is carried out by a laser heating or a plasma torch, nitrogen or an infrared oven. The system may include a calendering device. It can also be provided that the heating is carried out by the calendering device.

The implementation system of the method advantageously makes it possible to shape the two sets of fibers, for example, in the form of a strip or sheet, or a strip which is cut to the desired length. Preferably, the system for carrying out the method comprises a line of continuous formation of said material in the form of a calibrated and homogeneous strip of mineral fibers impregnated with thermoplastic polymer. The continuous training line comprises a device for setting up the two series of fibers provided with a first calendering device. The placing device also comprises a preheating device for attenuating or reducing the temperature differences caused by the inertia of fibers of different types when heating to the melting temperature. The placing device can also ensure the shaping of the material. However, the continuous training line comprises for this purpose, a shaping device implementing at least one operation of Ref: 0277-ARK12 calendering by means of a second calendering device and, preferably at least two calendering operations successive to obtain an impregnated fibrous material calibrated in a desired and homogeneous manner, that is to say without defect and without air bubble. For this, a third calendering device may be placed at the outlet of the second calendering device. The shaping device comprises a heating device for heating the two series of fibers to a temperature at least equal to the melting temperature Tf. In order to carry out the shaping in calibrated and continuous strip, each calendering device is notably provided with two cylinders, one of which has a male element ring, the other a flat-section female element groove of a determined width so that the fibers leaving the preheating device, are shaped in the groove by pressing the male element during their passage over the cylinder provided with the female element.

Of course to ensure the shaping and proper operation of the training line, each calendering device comprises a synchronous drive motor of the two cylinders and a cylinder heating system. In order to obtain the melting temperature of the polymer fibers, the shaping device comprises a heating device placed between the first and the second calendering device. The device for placing the fibers also comprises, at the line inlet, a continuous unwinding station of the two series of fibers followed by the preheating device. For this purpose, the unwinding station of the fibers is advantageously provided with coils with a horizontal unwinding axis. When the melting temperature Tf is high, preferably when it is greater than 200 ° C., as is the case, for example, for PAEK or PEEK fibers, it is intended to insert into the continuous training line, at the outlet of the shaping device, a cooling device. To allow easy packaging of the fibrous material web obtained, the continuous forming line advantageously comprises a winding device at the outlet of the cooling device. Preferably, the heating device and the preheating device 35 each consist of two half-ovens with horizontal aperture with tube lamps.

Ref: 0277-ARK12 infra red and adjustable temperature. At least one of the half-furnaces comprises a calibrated flat bottom groove on which the fibers side by side of the two sets of fibers rest. All of the electrically or electronically controlled elements 5 is advantageously controlled and synchronized by a computer-type control station. Other features and advantages of the invention will become clear from reading the description which is given below and which is given by way of illustrative and nonlimiting example and with reference to the figures in which: FIG. the diagram of a first implementation system of the method according to the invention, - Figure 2 shows the diagram of a second implementation system of the method according to the invention, - Figure 3 shows the diagram in cross-section AA of a fiber-coated support 50 according to the process; FIG. 4 shows the cross-sectional diagram BB of the support 50 after melting of the thermoplastic polymer fibers according to the method; FIG. 5 is a diagram of a third system for implementing the method. FIG. 6 represents the diagram of a third implementation system of the method according to the invention. FIG. 7 shows the diagram of a half-oven with the groove for placing fibers. - Figure 8 shows the schematic of calendering rolls with the complementary elements of calibration and shaping of the strip-shaped material. The systems shown in FIGS. 1, 2 and 5 allow implementation of the on-line and continuous manufacturing method proposed according to the invention for the manufacture of fibrous material pre-impregnated with thermoplastic polymer. Ref: 0277-ARK12 Each system comprises a device 100 for setting up the two series of fibers, namely the first series of fibers 1 which comprises mineral fibers and the second series of fibers 2 which comprises thermoplastic polymer fibers having their temperature melting point equal to Tf.

These devices have the same reference 100 in Figures 1, 2 and 5 and provide the same function namely to have the two sets of fibers in contact with one another. Each system also comprises a heating device 110 and possibly a calendering device 115 as is the case for the systems of FIGS. 1 and 5. It may be provided that the calendering device performs the heating function of two sets of fibers. . In the example of the system shown in Figure 1, the device 100 for placing fibers has two superimposed paths. The two series of fibers are brought by the two superimposed paths towards the same direction, these two paths approaching until the two sets of fibers are intercalated to form a homogeneous plane imposed by the size of the fibers, the fibers having constant dimensions. The homogeneous plane is in the form of a strip conveyed so as to pass in front of the heating device 110. This heating device makes it possible, in a few seconds, to reach the desired melting temperature Tf so that the thermoplastic polymer fibers having a melting temperature less than or equal to Tf, melt. The molten polymer adheres to the fibers of the first series (having mineral fibers). After passage to ambient temperature, the strip of fibrous material 10 thus produced can be used as required, for example, be cut by a cutting device 200 to enter the manufacture of mechanical parts. Figure 2 shows a device adapted to the establishment of two sets of fibers on a support 50 serving as a mold to form the structure of a 3D piece of fibrous material. In this example, the device for placing the fibers consists of two arms 102 and 103 disposed above a horizontal plane driven by a mechanical system (not represented as a treadmill 101). Several supports 50 are arranged on this mat. one behind the others following the

Ref: 0277-ARK12 without advancement. The arm 102 makes it possible to place the fibers of the first series 1 on a support 50 while the arm 103 makes it possible to place the fibers of the second series 2 on a support 50 on which the fibers of the first series have been put in place.

Of course, the arms 102 and 103 are motorized so that they can be moved closer to the surface of the supports 50 in order to have a good accuracy in setting up the fibers. For the net stop of the fibers at the edges of the supports 50, the system may comprise cutting arms.

When the supports 50 comprise the two sets of fibers, they are conveyed into the heating zone. Each support 50 is placed facing the heater 110 to allow the thermoplastic polymer fibers of the second series to melt. The diagram of FIG. 3 illustrates a support 50 covered with two sets of fibers 1 and 2, seen in cross section. The diagram of FIG. 4 makes it possible to illustrate this support 50 after melting the fibers of the second series. Only the fibers of the first series 1 can be seen on the section. In the example of the system shown in FIG. 5, the positioning device 100 comprises two channels whose exits are opposite each other. The two series of fibers 1 and 2 are brought by the two paths on the same plane so as to come into contact and to be intercalated in a zone of vis-à-vis and form a homogeneous plane imposed by the size of the fibers. The plane formed by the two sets of fibers in contact, passes for a few seconds in the heating zone provided to obtain the fusion of the thermoplastic polymer fibers. In this example, the calendering device 115 can additionally provide the heating function and substitute for the device 110. At the outlet of the calendering device, the fibrous material is obtained in the form of a strip 10 which can then be used as required. . In this example, the two series of fibers are each driven by a treadmill type device 111 and 112. It may advantageously be provided rules 113 and 114 for maintaining the spacing of fibers on each of the mats.

Ref: 0277-ARK12 It is understood that when talking about putting the fibers into contact by intercalating them, this is not limited to placing a fiber of a series between two fibers of the other series. Indeed, the positioning devices 100 allow to place two fibers side by side of the same series between two fibers of the other series. Preferably, such an arrangement will be used to have for example a mineral fiber for two thermoplastic polymer fibers. This is not limited to placing the fibers of the two series side by side. It may also be provided, in the case where the mineral fibers are already a weave of two-way weaving type, to put the thermoplastic polymer fibers in contact with this weaving, for example by placing them on one side of the weaving, this face being then facing the heater. Other systems, for example the mechanical systems described in US Pat. No. 6,607,626; US 6,939,424 and US 7,235,149 may also be suitable for fiber placement. A third system for implementing the method according to the invention is illustrated in the diagram of FIG. 6. Details of certain elements are illustrated in FIGS. 7 and 8. According to this preferred embodiment, the system comprises a line L. 20 of continuous formation of the material in the form of a calibrated and homogeneous band. This continuous training line comprises: the device for placing the fibers 100 equipped with: the device for unrolling the fibers, 104; this device 104 comprises fiber coils 141 for the fibers of the first series and coils 142 for the fibers of the second series. In practice, there are as many coils as fibers and a reel 143. - the preheating device 105; it has two half-ovens horizontal opening, infrared ramps. Its length is 1 m. The maximum temperature attainable is 600 ° C. The passage groove 13 has a section of 40x40mm approximately. the calendering device 106; it comprises two cylinders as illustrated in FIG. 8, of diameter 100 mm, width 100 mm, a polished chrome surface Ra of less than 0.1 micron. The surface of the cylinders 15 and 17 Ref: 0277-ARK12 has elements 16 and 18, male and female of a shape suitable for interlocking one into the other, by pressure, so as to calibrate the strip 10 in width at 6mm, when passing over the cylinders. This device comprises an electric heating providing a maximum temperature at about 260 ° C, a heating cartridge with rotating collector supply and regulation by a surface thermocouple probe, a self-aligning bearing and adjustable spacing from 0 to 2mm by screw-nut , a synchronous drive of the two cylinders by chain or toothed belt, a geared motor with brushless brushless servomotor allowing to have a maximum line speed of 30m / min and an electrical synchronization with the pulling train. The shaping device 150 equipped with: the heating device 110 identical to the preheating device 105. The temperature of this device is set to reach the melting temperature Tf of the thermoplastic polymer fibers. The half-furnace 11 comprises a passage groove 13 shown in FIG. 7; a second calendering device 115; a third calendering device 116; these calendering devices are identical to the first calendering device 106. The details of the structure of the cylinders are illustrated in the diagram of FIG. 8. The cooling device 117. It is in the form of a tray of length 1 m in stainless steel in which the band is introduced and immersed in cold water if necessary (the band is shown in dotted lines in the ferry crossing). It includes a compressed air dryer and a water cooling unit of about 3KW. - The device 118 for regulating the winding and maintaining the band preventing vibrations and operating from top to bottom on a height corresponding to the width of the winding coils 300. - The winding device 300, this device comprises several flat coils shaped slabs 301, 302 etc., about 600mm in diameter. The slabs are superimposed on a vertical axis XX as filling progresses. It is planned to store 10 to 20 pancakes with an interlayer between them. The passage of a slab 301 to the next 302 is done manually. The synchronization with pulling of the band is done by a regulating pad, the tension is regulated by the weight of the pad. Ref: 0277-ARK12 - The draw train 350 which allows to train the band continuously. It comprises elastomer rollers and allows to exert a fixed pressure by pneumatic cylinder. It is electrically synchronized with the calendering devices.

The continuous training line L is controlled by a control station 400, the computer type with display screen. This station 400 is connected, for example by network, to the various electrical control devices of the line: electric motors; variable speed drives and speed controllers, temperature controllers; pulling motor to allow the different synchronizations necessary for the continuous operation of line L. This control station also allows to save all the parameters for automation and synchronization management. In the case where the mineral fibers 1 used have a coating layer (or sizing), the coating layer may be removed, if necessary, that is to say, in the event of incompatibility with thermoplastic polymer fibers to melt . The coating layer will be removed before contacting the two sets of fibers 1, 2. For this purpose, it can be expected that the fibers of the two series arrive by two separate reels so that the desizing is performed on the mineral fibers before contacting the two sets of fibers; or that the desensitization of the mineral fibers is carried out in an oven such as oven 105 before contacting the two sets of fibers in the oven 105. In addition, to obtain an improved melting and impregnation, a heating device 110 may be used. laser type instead of an infrared oven as described in the previous example. In this case, the laser device is arranged so that the laser beam arrives in the longitudinal axis of the fibers (ribbon), that is to say the axis of pulling. Thus the heating is direct and therefore concentrated on the fibers.

Ref: 0277-ARK12

Claims (14)

REVENDICATIONS1. A process for producing a thermoplastic polymer prepreg fiber material comprising i) using at least two sets of different fibers, a first series of fibers comprising mineral fibers and a second series of fibers comprising thermoplastic polymer fibers having a melting temperature Tf, ii) arranging the two sets of fibers in contact with each other and then iii) heating all of the two series of fibers to a temperature at least equal to the melting temperature Tf of the thermoplastic fibers and allow all to cool to room temperature; characterized in that it comprises a preheating step of preheating to a temperature below the melting temperature Tf, the two series of fibers in contact with each other. 2. Process for manufacturing a fibrous material pre-impregnated with thermoplastic polymer, according to claim 1, characterized in that the heating at the melting temperature Tf is associated with a shaping of the set of two sets of fibers. . 3. A method of manufacturing a fibrous material pre-impregnated with thermoplastic polymer, according to one of claims 1 and 2, wherein the establishment of two sets of fibers and the shaping of the impregnated material thermoplastic fibers fused are carried out by a system comprising the implementation of calendering operations. 4. System for manufacturing a fibrous material pre-impregnated with thermoplastic polymer for carrying out the method according to any one of the preceding claims, characterized in that it comprises a line (L) for continuous formation of said material under form of a band (20) calibrated and homogeneous mineral fibers impregnated with thermoplastic polymer, comprising a device (100) for placing two sets of fibers (1, 2) provided with a first (106) calendering device and a shaping device (150) provided with a second (115) calendering device. Ref: 0277-ARK12 5. A system for manufacturing a fibrous material pre-impregnated with thermoplastic polymer, according to claim 4, characterized in that the device (100) for placing the two sets of fibers further comprises a station (104) unfolding of fibers, provided with coils (141, 142) having a horizontal unwinding axis and a preheating device (105) placed between the unwinding station (104) and the first calendering device (106), the device (105) preheating being able to receive the fibers of the unwinding station. 6. System for manufacturing a fibrous material pre-impregnated with thermoplastic polymer, according to claim 4, characterized in that the shaping device (150) further comprises a heating device (110) whose temperature can be at least equal to the melting temperature Tf of the thermoplastic fibers, placed between the first (106) and the second (115) calendering device. 7. A system for manufacturing a fibrous material pre-impregnated with thermoplastic polymer, according to claim 4, characterized in that the shaping device (150) comprises a third (116) calender. 8. System for manufacturing a fibrous material pre-impregnated with thermoplastic polymer, according to any one of claims 4 to 7, characterized in that the line (L) for continuous formation of the fibrous material in the form of a strip, also comprises a cooling device (117) at the outlet of the shaping device (150). 9. System for manufacturing a fibrous material pre-impregnated with thermoplastic polymer, according to any one of claims 1 to 8, characterized in that the line (L) for continuous formation of the fibrous material in the form of a strip comprises a device (300) for winding the strip at the outlet of the cooling device (117). Ref: 0277-ARK12 10. System for manufacturing a fibrous material pre-impregnated with thermoplastic polymer, according to claim 4 or 7, characterized in that each device (106, 115, 116) for calendering is provided with two cylinders (15, 17) of which one has a ring (16) male member, the other a groove (18) female member of a shape suitable for interlocking one into the other by pressure so as to calibrate the band width during its passage on the cylinders. A system for manufacturing a fibrous material pre-impregnated with a thermoplastic polymer, according to claim 4 or claim 7, characterized in that each calendering device (106, 115, 116) comprises a synchronous drive motor (19). ) of the two cylinders and a cylinder heating system (14). 12. System for manufacturing a fibrous material pre-impregnated with thermoplastic polymer, according to one of claims 5 and 6, characterized in that the heating device (110) and the preheating device (105) each consist of two half-ovens with adjustable infrared lamps infrared lamps, at least one of the half-furnaces having a groove (13) flat bottom, calibrated and intended to receive the fibers side by side of the two sets of fibers. 13. Manufacturing system according to claim 4, characterized in that it comprises a pull train (350) synchronized with the calendering devices. 14. Manufacturing system according to claim 4, characterized in that it comprises a cockpit and synchronization controls devices of the continuous formation line of the material. Ref: 0277-ARK1230