Fiber material impregnated with a thermoplastic polymer of optimal molecular weight and viscosity, and method for producing the same.

Abstract

This invention provides an impregnated fiber material that offers an excellent compromise between impregnation quality, compatibility with autoclaving-free fixation techniques, and mechanical properties, without the need to use polymers derived from reactive precursors. [Solution] An impregnated fiber material comprising a fiber material of at least one continuous fiber in the form of roving or several parallel rovings and at least one thermoplastic polymer matrix, wherein the thermoplastic polymer is an amorphous or semi-crystalline polymer having a glass transition temperature such as Tg≧40℃ as measured according to standard ISO 11357-2:2013, the fiber content in the impregnated fiber material is 45~65 volume%, the number average molecular weight Mn of the thermoplastic polymer is 11,000~25,000 g / mol, and the melt viscosity of the thermoplastic polymer is 80~1500 Pa·s as measured by planar / planar rheology at a temperature of 1 Hz and 2% deformation, Tg+220℃.

Description

[Technical Field]

[0001] The present invention relates to a fibrous material impregnated with an amorphous or semi-crystalline thermoplastic polymer having a glass transition temperature such as Tg ≥ 40°C, particularly Tg ≥ 100°C, and especially ≥ 120°C, wherein the impregnated fibrous material has a fiber content of 45 to 65 volume%, preferably 50 to 60 volume%, and particularly 54 to 60 volume%, the number-average molecular weight Mn of the thermoplastic polymer is 11,000 to 25,000 g / mol, and the melt viscosity of the thermoplastic polymer is 80 to 1500 Pa·s as measured by planar-planar rheology at 1 Hz and 2% deformation, and at a temperature of Tg + 220°C.

[0002] More specifically, the present invention aims to propose an impregnated fiber material as defined above, wherein the polymolecular index Ip of the thermoplastic polymer is 2 to 6, particularly 2 to 3.5, especially 2.5 to 3.5.

[0003] The present invention also relates to a method for preparing the fibrous material and, in particular, to its use for manufacturing composite components by automated laying by robots or by filament winding.

[0004] In this invention, "fiber material" refers to an aggregate of reinforcing fibers for a solid. After impregnation with resin, it takes the form of a ribbon (tape), a layer, or an extruded plate.

[0005] The term "ribbon" (or tape) refers to a strip, which is a thin, semi-finished product consisting of a single roving of fibers, with uncalibrated width and thickness, or a thin, calibrated band consisting of one or more fiber rovings.

[0006] This fibrous material can also be pre-impregnated with resin only, generally yielding semi-finished products in the form of fabric or NCF, which can be assembled and integrated to produce thermoformable composite panels, or placed directly into molds to produce final parts.

[0007] Such pre-impregnated or impregnated fiber materials are particularly suitable for producing lightweight composite materials for manufacturing mechanical parts with three-dimensional structures and good mechanical and thermal properties. When the fibers are made from carbon and / or the resin is filled with appropriate additives, these fiber materials can discharge static charge. The use of flame-retardant additives in flame-retardant or non-flame-retardant resins makes the impregnated fiber material fire-resistant. Therefore, it possesses properties that make it suitable for the manufacture of parts, particularly in the fields of machinery, aerospace, marine, automotive, petroleum and gas, especially marine, gas storage, energy, healthcare, sports and recreation, and electronics.

[0008] Such impregnated fiber materials, also called composite materials, comprise a fiber material consisting of reinforcing fibers and a matrix consisting of a polymer impregnated with the fibers. The primary role of this matrix is ​​to keep the reinforcing fibers in a compact shape, thereby imparting the desired shape to the final product. The matrix also ensures charge transfer between fibers, thus regulating the mechanical strength of the composite. Furthermore, the matrix protects the reinforcing fibers from abrasion and erosion environments, controls surface appearance, and dissipates charge between fibers. The role of this matrix is ​​crucial for the long-term retention of the composite material, particularly with respect to fatigue and creep. [Background technology]

[0009] The good quality of three-dimensional composite components manufactured from impregnated fiber materials is generally achieved by the proficiency in the method of pre-impregnating or impregnating the reinforcing fibers with thermoplastic polymers, and therefore by the proficiency in the resulting final impregnated fiber material.

[0010] The drawback of the current technology lies in the difficulty in achieving good fiber impregnation, despite its good mechanical properties. Achieving good mechanical properties requires a high molar mass, which implies high viscosity; therefore, finding such a compromise is difficult.

[0011] Thus, molar mass affects the Tg value of the resin, and Tg increases with molar mass until it reaches a certain percentage at which Tg no longer fluctuates significantly. Tg has a primary effect on the mechanical properties of the resin, particularly its modulus and the temperature stability of this modulus, and it is common practice to use composite materials only up to a maximum temperature equal to Tg -10 to -30°C.

[0012] As the molar mass increases, the tensile strength of the composite also increases; however, the viscosity of the molten resin increases, making fiber impregnation more difficult. Furthermore, in this process, the movement of fibers and resin is necessary for filling pores, especially between bands and intertapes, making the final fixing of the composite component more difficult.

[0013] Since viscosity depends on the difference between the operating temperature and the polymer's Tg, this problem is further exacerbated when the polymer's Tg is high.

[0014] To date, the production of ribbons of fibrous materials reinforced by impregnation with thermoplastic or thermosetting polymers has been carried out using several methods, particularly depending on the properties of the polymer, the desired type of final composite material, and the field of application. Some of these methods consist of an impregnation step, followed by a hot rolling or drying step of the impregnated fibrous material, and optionally, a melting step of the thermoplastic polymer.

[0015] Thus, wet impregnation techniques or those using liquid precursors or precursors with very low viscosity that polymerize in situ are often used to impregnate reinforcing fibers with thermosetting polymers, such as epoxy resins, as described in patent WO2012 / 066241A2. Since these rarely have liquid precursors, these techniques are generally not directly applicable to impregnation with thermoplastic polymers.

[0016] Therefore, current techniques for impregnating fiber materials and forming such impregnated fiber materials in the form of calibrated ribbons have several drawbacks. For example, it is difficult to uniformly heat the molten mixture of thermoplastic polymer in the die and at the die exit to the core of the material, thus altering the quality of impregnation. Furthermore, the temperature difference present between the molten mixture of fiber and polymer in the furnace, especially under infrared radiation, also alters the quality and homogeneity of the impregnation. Moreover, with this impregnation method via the melting path, it is not possible to obtain high levels of fiber or high production rates, especially when the thermoplastic resin has a high viscosity and therefore a high glass transition temperature, which is necessary to obtain high-performance composite materials.

[0017] In particular, the impregnation method by crosshead die extrusion of molten polymers is only suitable for low-viscosity thermoplastic polymers. Therefore, thermoplastic polymers, especially those with high glass transition temperatures, have too high a viscosity in the molten state to adequately impregnate the fibers, resulting in poor quality semi-finished or final products.

[0018] In this case, the next step is to use a prepolymer and perform pre-impregnation with a readily impregnable, fluid product, whether it is reactive on its own, reactive with each other, or a prepolymer and chain extender, and then heat the pre-impregnated product to complete the impregnation.

[0019] However, the use of prepolymers presents other drawbacks. In particular, prepolymers must have a relatively slow reaction rate to enable impregnation, but also a relatively fast reaction rate to allow for manufacturing that fits the rhythm of industry. This requires a compromise that is sometimes difficult to achieve. [Overview of the project]

[0020] Accordingly, the present invention aims to address at least one of the disadvantages of the prior art, and in particular, to obtain an impregnated fibrous material defined above using a thermoplastic polymer matrix, wherein three of the parameters, melt viscosity, implementation temperature, and weight-average molecular weight, are optimally selected to allow the use of a non-reactive thermoplastic polymer rather than a polymer derived from a reactive precursor (prepolymer or monomer), thereby enabling the avoidance of the disadvantages of the prepolymer or monomer. [Modes for carrying out the invention]

[0021] Therefore, an object of the present invention is an impregnated fibrous material comprising a fibrous material in the form of roving or a plurality of parallel rovings and at least one continuous fiber in the form of at least one thermoplastic polymer matrix, wherein the at least thermoplastic polymer is an amorphous or semicrystalline polymer having a glass transition temperature such as Tg≧40℃, particularly Tg≧100℃, especially ≧120℃, the fiber content in the impregnated fibrous material is 45-65 vol%, preferably 50-60 vol%, particularly 54-60 vol%, the number average molecular weight Mn of the thermoplastic polymer is 11,000-25,000 g / mol, and the melt viscosity of the thermoplastic polymer is 80-1500 Pa·s as measured by planar-planar rheology at 1 Hz and 2% deformation, at a temperature of Tg+220℃.

[0022] The glass transition temperature (Tg) of the thermoplastic polymer matrix is ​​measured using a differential scanning calorimeter (DSC) after a second heating cycle according to standard ISO 11357-2:2013. The heating and cooling rates are 20°C / min.

[0023] The inventors have thus been able to impregnate a fibrous material with a non-reactive thermoplastic polymer having a specific melt viscosity and weight-average molecular weight at the processing temperature of the fibrous material polymer, without the need to use a polymer derived from a reactive precursor (prepolymer or monomer), thus leading to obtaining an impregnated fibrous material having an excellent compromise between impregnation quality, compatibility with fixation techniques without autoclave, and mechanical properties.

[0024] In other words, the inventors have found that in order to have good impregnation of the fibrous material, it is necessary to obtain a glass transition temperature Tg + 220 °C, which makes it possible to obtain a conversion or processing temperature sufficient to have not only a good melt viscosity but also a weight-average molecular weight sufficient to guarantee good mechanical properties.

[0025] First, the various proportions of the component monomers of the polymer are selected to achieve a weight-average molar mass of at least 11,000 g / mol to less than 25,000 g / mol, for example using a chain limiter, thereby making it possible to control the molar mass of the polymer and, after impregnation of the fibrous material, to obtain a polymer that makes it possible to obtain a composite material having good mechanical properties without disturbing the impregnation of the fibrous material by the melt viscosity obtained at this temperature of 80 to 1500 Pa·s at the conversion or processing temperature of Tg + 220 °C.

[0026] Thus, when the conversion or processing temperature is adopted equivalent to Tg + 150 °C, the melt viscosity at this temperature becomes less fluid compared to that obtained at the temperature Tg + 220 °C. However, even within the claimed range of melt viscosity of 80 to 1500 Pa·s, the number-average molecular weight must then be less than the critical number-average molecular weight of 11,000 to 25,000 g / mol and the impregnation is not carried out correctly.

[0027] Conversely, at a Tg higher than Tg + 220 °C, there is then a risk of degradation of the product at this temperature, and thus the resulting product exhibits insufficient mechanical properties despite the correct molecular weight and good viscosity.

[0028] Therefore, there is indeed a good compromise between three factors: the temperature of conversion or implementation, i.e., Tg + 220°C; viscosity, i.e., 80-1500 Pa·s.; and the critical number-average molecular weight, which must be 11,000-25,000 g / mol.

[0029] The term "non-reactive thermoplastic polymer," when used in reference to the final polyamide polymer in a thermoplastic matrix, means that the thermoplastic polymer has a molecular weight that does not change significantly, and its number-average molecular weight (Mn) changes by less than 20%.

[0030] The number-average molar mass (Mn) and weight-average molar mass (Mw) of the polymer were determined by steric exclusion chromatography according to standards ISO 16014-1:2012, 16014-2:2012, and 16014-3:2012, using the following conditions: Equipment: Waters Alliance 2695 aircraft Solvent: Hexafluoroisopropanol stabilized with 0.05 M potassium trifluoroacetate. Flow rate: 1ml / min Column temperature: 40℃ Two columns, in series: 1000 Å PFG and 100 Å PFG (PPS) Sample concentration: 1 g / l (dissolved at room temperature for 24 hours) Sample filtration was performed using an ACRODISC PTFE filter (25 mm diameter, 0.2 μm pores) and a syringe. Injection volume: 100μL UV detection at 228nm and refractive index detection at 40°C. 1,900,000~402 g.mol -1 Calibration according to PMMA standards. Calibration curve modeled by a fifth-degree polynomial.

[0031] The melt viscosity is measured by rheology, which vibrates between two parallel planes with a diameter of 25 mm at a temperature Tg + 220°C, using a Physica MCR301 machine.

[0032] Viscosity is measured over a period of up to 10 minutes.

[0033] It is quite obvious that non-reactive thermoplastic polymers must be stable at the temperature at which their melt viscosity is measured.

[0034] If the thermoplastic polymer is not stable at this temperature, it is necessary to stabilize the polymer, in particular, by adding 0.1-4%, and especially 0.1-1%, of an antioxidant or a mixture of antioxidants proportional to the weight of the thermoplastic polymer.

[0035] Advantageously, the antioxidant is selected from hindered phenols such as Irganox® (BASF) or BHT (butylhydroxytoluene), secondary aromatic amines such as alkyldiphenylamines, phosphites such as tri(2,4-di-tert-butylphenyl) phosphite, or Irgafos® (CIBA).

[0036] Advantageously, the difference between the melting temperature Tm of the at least semicrystalline thermoplastic polymer and its Tg is 200°C or less (Tm-Tg ≤ 200°C).

[0037] In one embodiment, the polymolecular index Ip of the thermoplastic polymer is 2 to 6, particularly 2 to 3.5, and especially 2.5 to 3.5.

[0038] The polymolecular index is denoted as Ip and is measured by steric exclusion chromatography or gel permeation chromatography, corresponding to the ratio Mw / Mn.

[0039] The polymolecularity index provides an initial idea about the distribution of molar masses of various macromolecules within a polymer. In a perfect polymer, all macromolecules are linear, having the same length and therefore the same molar mass, and the polymolecularity index Ip is equal to 1. Among various monomers, for polyamides obtained by polycondensation from diamines and dicarboxylic acids, the expected polymolecularity index Ip is 2.0.

[0040] A polymolecular index greater than 2 may be due to the presence of branching or divergence in the polymer's main chain. In the case of copolyamides, this can appear at the nitrogen atoms of the amide functional groups. Therefore, it can be quantified by NMR (nuclear magnetic resonance) by comparing the level of (branched) tertiary aromatic amides to the level of (linear) secondary aromatic amides.

[0041] The presence of branching affects the viscosity of the resin. The more branches there are, the higher the viscosity, which in turn leads to insufficient impregnation.

[0042] Therefore, it is necessary to control the level of branching in the thermoplastic polymer used.

[0043] Throughout this specification, the terms “pre-impregnated” or “pre-impregnated” are used to refer to a fibrous material on which a thermoplastic polymer is deposited before the polymer is melted on the fibrous material, and the terms “impregnated” or “impregnated” are used to refer to a fibrous material on which the thermoplastic polymer has been melted in particular by a heating system, or a fibrous material on which impregnation has been completed.

[0044] Thermoplastic polymer matrix The aforementioned thermoplastic polymer matrix is ​​an amorphous or semi-crystalline polymer having a glass transition temperature such as Tg ≥ 40°C, particularly Tg ≥ 100°C, and especially ≥ 120°C.

[0045] The number-average molecular weight Mn of the thermoplastic polymer is 11,000 to 25,000 g / mol, and the melt viscosity of the thermoplastic polymer is 80 to 1500 Pa·s, measured by planar-planar rheology at 1 Hz and 2% deformation, at a temperature of Tg + 220°C.

[0046] Thermoplastics or thermoplastic polymers generally refer to materials that are solid at room temperature, and may be semi-crystalline or amorphous. They soften as the temperature rises, especially after passing their glass transition temperature (Tg). If amorphous, they become fluid at higher temperatures. If semi-crystalline, they may exhibit a sharp transition after passing their so-called melting temperature (Tm), and become solid again when the temperature drops below their crystallization temperature (for semi-crystalline materials) and their glass transition temperature (for amorphous materials).

[0047] Tg and Tm are determined by differential scanning calorimetry (DSC) according to standards 11357-2:2013 and 11357-3:2013, respectively.

[0048] Regarding the polymers used to create the impregnation matrix of fibrous materials, it is advantageous for them to be thermoplastic polymers or mixtures of thermoplastic polymers.

[0049] This polymer or mixture of thermoplastic polymers can be ground into a powder so that it can be used in equipment such as tanks, particularly in fluidized beds or aqueous dispersions.

[0050] The tank configuration, particularly for fluidized beds, can be open or closed.

[0051] The thermoplastic polymer that enters into the assembly of the impregnation matrix of the fiber material is - Polymers and copolymers of the group of aliphatic, alicyclic, or semi-aromatic polyamides (PA) (also known as polyphthalamides (PPA)), - Polyureas, especially aromatic polyureas, - Polymers and copolymers of the acrylic group, such as polyacrylates, more specifically polymethyl methacrylate (PMMA) or its derivatives. - Polymers and copolymers of poly(aryl ether ketone) (PAEK) such as polyether ether ketone (PEEK), or poly(ether ketone ketone) (PEKK) or its derivatives such as poly(aryl ether ketone ketone) (PAEKK), - Aromatic polyether-imide (PEI), - Polyaryl sulfides, especially polyphenyl sulfides (PPS), - Polyaryl sulfides, especially polyphenylene sulfone (PPSU), - Polyolefins, - Polylactic acid (PLA), - Polyvinyl alcohol (PVA), - Fluorinated polymers, particularly polytetrafluoroethylene (PTFE) or polychlorotrifluoroethylene (PCTFE), and mixtures thereof can be selected.

[0052] Advantageously, the prepolymers constituting the matrix are selected from polyamides (PA), particularly aliphatic polyamides, alicyclic polyamides, and semi-aromatic polyamides (polyphthalamides) (which may optionally be modified with urea units), and copolymers thereof, polymethyl methacrylate (PPMA) and its copolymers, polyetherimide (PEI), polyphenylene sulfide (PPS), polyphenylene sulfone (PPSU), polyether ketone (PEKK), and polyether ether ketone (PEEK).

[0053] For the fluorinated polymer, 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 be greater than 80% by weight, or even better than 90% by weight, in order to ensure good mechanical and chemical resistance of the structural component, especially when subjected to thermal and chemical stress. The comonomer must be a fluorinated monomer, such as vinyl fluoride.

[0054] With respect to structural components that must withstand high temperatures, apart from fluorinated polymers, according to the present invention, PAEK (polyaryl ether ketone), such as poly(ether ketone)PEK, poly(ether ether ketone)PEEK, poly(ether ketone ketone)PEKK, poly(ether ketone ether ketone ketone)PEKEKK, or PA with a high glass transition temperature Tg is advantageously used.

[0055] When the polymer is a mixture of two polymers P1 and P2, it is advantageous for the weight ratio of polymers P1 and P2 to be between 1-99% and 99-1%.

[0056] Advantageously, when the thermoplastic polymer is a mixture and the pre-impregnation method uses a dry powder, the mixture takes the form of a powder obtained by dry blending before introduction into the pre-impregnation tank, or by dry blending directly in the tank, or by grinding a pre-formed compound in an extruder.

[0057] In the first modification, the number-average molecular weight Mn of the thermoplastic polymer is 14,000 to 25,000, preferably 15,000 to 21,000, the melt viscosity of the thermoplastic polymer is 150 to 1500 Pa·s, preferably 200 to 750 Pa·s, at a temperature of Tg + 220°C, and the thermoplastic polymer is a polymer having Tg ≥ 130°C.

[0058] Therefore, the thermoplastic polymer may be any thermoplastic polymer defined above, as long as its Tg ≥ 130°C.

[0059] Optionally, the thermoplastic polymer or mixture of thermoplastic polymers further comprises carbon-based fillers, particularly carbon black, or carbon-based nanofillers selected from graphene, carbon nanotubes, carbon nanofibrils, or mixtures thereof. These fillers enable electrical and / or thermal conductivity, thus facilitating the melting of the polymer matrix when heated.

[0060] Optionally, the thermoplastic polymer may include at least one additive selected from catalysts, antioxidants, heat stabilizers, UV stabilizers, light stabilizers, lubricants, fillers, plasticizers, flame retardants, nucleating agents, chain extenders, and dyes, electrical conductors, thermal conductors, or mixtures thereof.

[0061] The aforementioned additives are advantageously selected from heat stabilizers, antioxidants, flame retardants, electrical conductors, and thermal conductors.

[0062] Thermoplastic polymers or mixtures of thermoplastic polymers may further include liquid crystal polymers or cyclized polybutylene terephthalate, or mixtures containing the latter, such as CBT100 resin marketed by CYCLICS CORPORATION. These compounds allow the polymer matrix to be fluidized in a molten state, particularly for better penetration into the fiber core. One or more of these compounds are selected depending on the properties of the polymer or polymer mixture of thermoplastic polymers used to implement the impregnation matrix, especially its melting point.

[0063] Advantageously, the at least one thermoplastic polymer is selected from polyamide, PEKK, PEI, and mixtures of PEKK and PEI.

[0064] Advantageously, if the polymer is a mixture of two polymers P1 and P2, this mixture consists of a powder obtained by dry blending before or directly in the tank, and this mixture of the two polymers P1 and P2 is a mixture of PEKK and PEI.

[0065] Advantageously, the PEKK / PEI mixture is 90-10% to 60-40% by weight, especially 90-10% to 70-30% by weight.

[0066] In this first modification, the thermoplastic polymer may therefore be any thermoplastic polymer defined above, as long as Tg ≥ 130°C.

[0067] Polyamide thermoplastic polymer matrix In one embodiment of the first modification defined above, the at least one thermoplastic polymer is a polyamide, in particular a heat-stabilized polyamide.

[0068] Heat stabilizers are especially necessary for polyamides that are likely to degrade at a temperature of Tg + 220°C.

[0069] The nomenclature used to specify polyamides is described in ISO standard 1874-1:2011 “Plastiques -- Materiaux polyamides (PA) pour moulage and extrusion -- Partie 1: Designation”, particularly on page 3 (Tables 1 and 2), and is well known to those skilled in the art.

[0070] Polyamides can be homopolyamides, copolyamides, or mixtures thereof.

[0071] In this first variation, the thermoplastic polymer is a polyamide having a Tg ≥ 130°C, particularly a heat-stabilized polyamide, and advantageously, the polyamide is a semi-aromatic polyamide.

[0072] As for semi-aromatic polyamides, they are optionally modified with urea units, and are in particular semi-aromatic polyamides of formula X / YAr as described in EP1505099, where, Y represents an aliphatic diamine residue having 8 to 20 carbon atoms. Ar represents a residue, an aromatic dicarboxylic acid group. X represents NH2-(CH2)10-COOH aminoundecanoic acid, lactam 12, or a residue of the corresponding amino acid, or a Y,x pattern group from the condensation of a diamine with an aliphatic diacid (x) having 8 to 20 carbon atoms, or a Y,I pattern group from the condensation of a diamine with an isophthalic acid.

[0073] X / YAr polyamide is a semi-aromatic polyamide of formula A / XT, where A is selected from a unit obtained from at least one amino acid, a unit obtained from at least one lactam, and at least one unit corresponding to the formula (Ca diamine)(Cb diacid), where a represents the number of carbon atoms in the diamine and b represents the number of carbon atoms in the diacid, and a and b are each 4 to 36, preferably 9 to 18. The unit (Ca diamine) is selected from linear or branched aliphatic diamines, alicyclic diamines, and alkyl aromatic diamines. The unit (Cb diacid) is selected from linear or branched aliphatic diamines, alicyclic diamines, and aromatic diamines. XT represents a unit obtained by polycondensation of Cx diamine and terephthalic acid, where x represents the number of carbon atoms in the Cx diamine, and x is 6 to 36, preferably 9 to 18.

[0074] A / XT is a polyamide of formula A / 6T, A / 9T, A / 10T, or A / 11T (where A is as defined above), specifically polyamides PA6 / 6T, PA66 / 6T, PA6I / 6T, PA MXDT / 6T, PA MPMDT / 6T, PA PA11 / 10T, PA11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA 11 / BACT, PA BACT / 10T / 6T, PA 11 / BACT / 6T, PA 11 / MPMDT / 6T, PA 11 / BACT / 10T, PA 11 / MXDT / 10T, PA 11 / MXDT / 6T.

[0075] For copolyamides having the formula A / XT, the ratio of A to XT is a function of Tg, and in this case, it is clear that the temperature must be 130°C or higher.

[0076] T corresponds to terephthalic acid, MXD to m-xylylenediamine, MPMD to methylpentamethylenediamine, and BAC to bis(aminomethyl)cyclohexane, which can be either 1,3-BAC or 1,4-BAC.

[0077] Advantageously, the polyamide is a semi-aromatic polyamide selected from PA MXDT / 6T, PA MPMDT / 6T, PA 11 / BACT, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA 11 / BACT / 6T, PA 11 / MPMDT / 6T, PA 11 / BACT / 10T, PA 11 / MXDT / 10T, and PA 11 / MXDT / 6T.

[0078] In the second modification, the number-average molecular weight Mn of the thermoplastic polymer is 11,000 to 20,000 g / mol, preferably 12,000 to 18,000, the melt viscosity of the thermoplastic polymer is 80 to 650 Pa·s at a temperature of Tg + 220°C, preferably 100 to 450 Pa·s, and the thermoplastic polymer is a polyamide having Tg < 130°C.

[0079] In this second variation, the thermoplastic polymer may therefore be only polyamides having a Tg < 130°C.

[0080] Advantageously, the polyamide is selected from aliphatic polyamides, alicyclic polyamides, and semi-aromatic polyamides having a Tg of less than 130°C, preferably aliphatic polyamides and alicyclic polyamides.

[0081] Aliphatic and alicyclic polyamides consist of repeating aliphatic units selected from units obtained from the polycondensation of at least one amino acid, and units obtained from the polycondensation of at least one lactam (as an aliphatic polyamide), or repeating units X·Y obtained from the polycondensation of at least one diamine selected from linear (or branched) aliphatic diamines and at least one dicarboxylic acid selected from difatty acids and dicyclofatty acids, as well as as alicyclic polyamides. The diamine and the diacid each contain 4 to 36 carbon atoms, preferably 6 to 18 carbon atoms.

[0082] It is clear that the alicyclic polyamide contains at least one dicycloaliphatic amine and / or dicyclo fatty acid in an XY unit.

[0083] Advantageously, if the thermoplastic polymer is an aliphatic polyamide, it is - Selected from polyamide 6 (PA-6), polyamide 11 (PA-11), polyamide 12 (PA-12), polyamide 66 (PA-66), polyamide 46 (PA-46), polyamide 610 (PA-610), polyamide 612 (PA-612), polyamide 1010 (PA-1010), polyamide 1012 (PA-1012), polyamide 11 / 1010 and polyamide 12 / 1010, or mixtures thereof or copolyamides thereof, and block copolymers, in particular polyamide / polyether (PEBA).

[0084] Semi-aromatic polyamides are defined above, provided their Tg is less than 130°C, and are selected in particular from the following: MXD10, MXD6, PA 6 / 6T, PA 66 / 6T, PA 6I / 6T, MPMDT / 10T, 11 / MPMDT / 10T, MPMDT / 6T, PA BACT / 10T, PA 11 / BACT / 10T, MXDT / 10, and PA 11 / MXDT / 10T.

[0085] Textile materials: With respect to the fibers constituting the aforementioned fibrous material, they are, in particular, continuous fibers of mineral, organic, or plant origin in the form of rovings.

[0086] Advantageously, the number of fibers in the fibrous material as carbon fiber is 3K or more, particularly 6K or more, and particularly 12K or more.

[0087] Advantageously, the number of fibers in the fibrous material as carbon fiber is 12K or more, particularly 12K, 24K, 48K, 50K and 400K, particularly 12K, 24K, 48K and 50K.

[0088] Advantageously, the basis weight of the glass fiber is 1,200 tex or more, especially 2,400 tex or more, and 4,800 tex or more.

[0089] Tex means that 1000m of base yarn weighs 1g.

[0090] Examples of mineral fibers include carbon fibers, glass fibers, basalt fibers, silica fibers, or silicon carbide fibers. Examples of organic fibers include fibers based on thermoplastic or thermosetting polymers, such as semi-aromatic polyamide fibers, aramid fibers, or polyolefin fibers. Preferably, these are amorphous thermoplastic polymer systems, and when the impregnation matrix is ​​amorphous, they have a glass transition temperature Tg that is higher than the Tg of the thermoplastic polymer or polymer mixture constituting the matrix, or when the impregnation matrix is ​​semi-crystalline, they have a glass transition temperature Tg that is higher than the Tm of the thermoplastic polymer or polymer mixture constituting the matrix. Advantageously, these are semi-crystalline thermoplastic polymer systems, and when the impregnation matrix is ​​amorphous, they have a melting point Tm that is higher than the Tg of the thermoplastic polymer or polymer mixture constituting the matrix, or when the impregnation matrix is ​​semi-crystalline, they have a melting point Tm that is higher than the Tm of the thermoplastic polymer or polymer mixture constituting the matrix. Therefore, there is no risk of the organic fibers constituting the fiber material melting during the impregnation of the final composite material with the thermoplastic matrix. Plant fibers include natural linen, hemp, lignin, bamboo, silk, especially spider silk, sisal, and other cellulose fibers, particularly viscose. These plant fibers can be used in their pure form, or they can be treated or coated with a coating layer to facilitate adhesion and impregnation with a thermoplastic polymer matrix.

[0091] Furthermore, it can accommodate fibers that have supporting threads.

[0092] These component fibers can be used individually or in mixtures. Therefore, organic fibers can be impregnated with thermoplastic polymers and mixed with mineral fibers to form impregnated fiber materials.

[0093] Organic fiber roving can have several basis weights and several geometric shapes.

[0094] Preferably, the fibrous material consists of continuous carbon, glass, basalt, or silicon carbide fibers, or mixtures thereof, particularly carbon fibers. It is used in the form of rovings or several rovings, in which case each roving consists of a single roving with added fibers.

[0095] The fibers of the fibrous material may or may not be sized.

[0096] The term "sizing" refers to a surface treatment applied to a fibrous material during its manufacture. It can also refer to a transient pretreatment at the beginning of a pre-impregnation process, whether performed in conjunction with direct impregnation or not.

[0097] These are generally organic (thermosetting or thermoplastic resin types) and are often incorporated into polymer-reinforced fibers with low melting points (Tm) or thermosetting pre-impregnations with low Tg points.

[0098] Furthermore, these sizing measures are useful in protecting the dry fibers from damage during contact with the guide system.

[0099] In the case of non-sizing materials, the fibrous material may contain up to 0.1% by weight of an organic material called sizing (thermosetting or thermoplastic resin type).

[0100] In the case of a transient pretreatment performed initially by an impregnation device in the process of pre-impregnating reinforcing fibers, the sizing may be an organic liquid such as water, low-molecular-weight or high-molecular-weight alcohols (e.g., ethanol, methanol, isopropanol), or ketones (e.g., acetone), which serves as transient sizing; that is, it is present in contact with the fibers for a short time, allowing it to be handled in a "dry" state (i.e., before pre-impregnation), and then removed from the composite material so as not to disrupt the final properties of the composite.

[0101] In the case of sized materials, the fibrous material may contain 0.1% to 2.5% by weight of an organic material (thermosetting or thermoplastic resin type) called sizing.

[0102] Advantageously, the fibers in the fibrous material are not sized.

[0103] The term "unsized" means either that the fibers are not initially sized and therefore not surface-treated, or that the fibers are desized before use.

[0104] Advantageously, the volume content of the fibers is constant at at least 70% of the volume of the impregnated fiber material, particularly at least 80%, particularly at least 90%, and more specifically at least 95% of the volume of the impregnated fiber material.

[0105] Advantageously, the fiber distribution is uniform in at least 95% of the volume of the impregnated fiber material.

[0106] The volume percentage of fibers is measured locally relative to the representative basic volume (REV).

[0107] The term "constant" means that the volume percentage of the fibers is constant within a measurement uncertainty of plus or minus 1%.

[0108] The term "uniform" means that the impregnation is uniform, with at least 95% of the volume of the impregnated fiber material ribbon being dry, i.e., there are no unimpregnated fibers, and conversely, there are no zones of pure resin without fibers.

[0109] Advantageously, the porosity level in the impregnated fiber material is less than 10%, particularly less than 5%, and particularly less than 2%.

[0110] It should be noted that achieving a porosity level of zero is difficult, and therefore, a porosity level higher than 0% but lower than the above-mentioned level is advantageous.

[0111] The porosity level corresponds to the closed porosity level and can be determined by electron microscopy or as the relative deviation between the theoretical density and experimental density of the impregnated fiber material, as described in the section on examples of the present invention.

[0112] Advantageously, the impregnated fiber material is a single layer.

[0113] The term "single layer" means that, when a fibrous material is impregnated, the impregnation is carried out particularly uniformly to the core, especially with at least one expansion during the impregnation, so that the fibrous material and polymer cannot be separated from each other, forming a material composed of layers based on single fibers and polymer.

[0114] Advantageously, impregnated fiber materials are not flexible if not reheated.

[0115] This means that impregnated fiber materials cannot take on a composite shape at room temperature, and can only do so if the Tm is higher than that of the resin. In other words, impregnated fiber materials do not drape.

[0116] Conversely, if the fibrous material is pre-impregnated, it is flexible and, in the case of a shape that is not excessively complex, can at least conform to the shape of the mold.

[0117] The number of fibers, fiber content, sizing, fiber distribution, flexibility, and single-layer properties can each be combined with one or more others, in combination with those targeted by the present invention, and may be subject to as many combination embodiments as possible that form an integrated part of the present invention.

[0118] In impregnated materials, also known as "ready-to-use" materials, the polymer or a mixture of thermoplastic impregnating polymers is distributed uniformly and homogeneously around the fibers. In this type of material, the thermoplastic impregnating polymer must be distributed as homogeneously as possible within the fibers to obtain minimum porosity, i.e., minimum empty space between fibers. In fact, the presence of pores in this type of material can act as stress concentration points, for example, during mechanical tensile stress loading, which subsequently form crack initiation points in the impregnated fiber material, causing mechanical damage. Therefore, a homogeneous distribution of the polymer or a mixture of polymers improves the mechanical strength and uniformity of the composite material formed from these impregnated fiber materials.

[0119] Therefore, in the case of "ready-to-use" impregnated materials, the fiber level in the impregnated fiber material is 45-65 volume%, preferably 50-60 volume%, and particularly 54-60 volume%.

[0120] The impregnation ratio can be measured by dividing the surface area of ​​the polymer-impregnated ribbon by the total surface area of ​​the product (impregnated surface plus pore surface) through image analysis of the ribbon's cross-section (e.g., using a microscope, photograph, or digital camera). To obtain good quality images, it is preferable to coat the ribbon, cut in its transverse direction, with a standard polishing resin and polish it using a standard protocol to enable observation of the sample under a microscope at a magnification of at least 6×.

[0121] In another aspect, the present invention relates to a method for producing an impregnated fibrous material as defined above, characterized by comprising a step of pre-impregnating or impregnating the fibrous material, wherein at least the thermoplastic polymer is an amorphous or semi-crystalline polymer having a glass transition temperature such as Tg ≥ 40°C, particularly Tg ≥ 100°C, especially ≥ 120°C, the fiber content in the impregnated fibrous material is 45-65% by volume, preferably 50-60% by volume, particularly 54-60% by volume, the number-average molecular weight Mn of the thermoplastic polymer is 11,000-25,000 g / mol, and the melt viscosity of the thermoplastic polymer is 80-1500 Pa·s as measured by planar-planar rheology at 1 Hz and 2% deformation, at a temperature of Tg + 220°C.

[0122] All the features outlined above for fibrous materials and thermoplastic polymers are also effective in the aforementioned method.

[0123] In a first variation of the method, the method includes the step of impregnating the fiber material with at least a thermoplastic polymer, wherein the number average molecular weight Mn of the thermoplastic polymer is 11,000 to 20,000 g / m², preferably 12,000 to 18,000, the melt viscosity of the thermoplastic polymer is 80 to 650 Pa·s at a temperature of Tg + 220°C, preferably 100 to 450 Pa·s, and the thermoplastic polymer is a polymer having Tg < 130°C.

[0124] Advantageously, the polyamide having a Tg < 130°C is selected from aliphatic polyamides and alicyclic polyamides.

[0125] Advantageously, the aliphatic polyamide is polyamide 6 (PA-6), polyamide 11 (PA-11), polyamide 12 (PA-12), polyamide 66 (PA-66), polyamide 46 (PA-46), polyamide 610 (PA-610), polyamide 612 (PA-612), polyamide 1010 (PA-1010), polyamide 1012 (PA-1012), polyamide 11 / 1010, polyamide 12 / 1010, or mixtures thereof or copolymers thereof. Polyamides / polyethers (PEBA) and semi-aromatic polyamides, particularly semi-aromatic polyamides, are selected from among amides and block copolymers, especially those having a Tg < 130°C, and the semi-aromatic polyamides are selected from among MXD10, MXD6, PA6 / 6T, PA66 / 6T, PA6I / 6T, MPMDT / 10T, 11 / MPMDT / 10T, MPMDT / 6T, PABACT / 10T, PA11 / BACT / 10T, MXDT / 10, and PA11 / MXDT / 10T.

[0126] Advantageously, the pre-impregnation is carried out by the melting path at a particularly high speed, especially at a speed of >1 m / min, preferably >2 m / min, and more preferably >3 m / min.

[0127] Advantageously, in the first variation of the method defined above, the method is i) A step of obtaining an impregnated fiber material by impregnating a fiber material with at least one non-reactive thermoplastic polymer by a melting path, particularly by pultrusion of the molten polymer, by crosshead die extrusion, wherein the pre-impregnation step is performed using at least a thermoplastic polymer, the number average molecular weight Mn of the thermoplastic polymer is 11,000 to 20,000 g / m², preferably 12,000 to 18,000, the melt viscosity of the thermoplastic polymer is 80 to 650 Pa·s at a temperature of Tg + 220°C, preferably 100 to 450 Pa·s, and the thermoplastic polymer is a polymer having Tg < 130°C, step, ii) optionally includes a step of forming and calibrating the impregnated fiber material to obtain an impregnated fiber material consisting of a ribbon in the form of a thin band having a thickness of 0.2 to 5 mm, preferably 0.2 to 1.3 mm.

[0128] In this first modification, impregnation does not result in pre-impregnated fiber material, but rather impregnated fiber material, and therefore a subsequent heating step to complete the impregnation is not necessarily required. However, if the subsequent heating step is performed after the impregnation step, it would not be outside the scope of the present invention.

[0129] In a second modification, the method comprises the step of pre-impregnating the fibrous material, which takes the form of roving or several parallel rovings, with at least one non-reactive thermoplastic polymer, wherein the number-average molecular weight Mn of the thermoplastic polymer is 14,000 to 25,000, preferably 15,000 to 21,000, the melt viscosity of the thermoplastic polymer is 150 to 1500 Pa·s, preferably 200 to 750 Pa·s, at a temperature of Tg + 220°C, and the thermoplastic polymer is a polymer having Tg ≥ 130°C.

[0130] Advantageously, the at least one thermoplastic polymer is a particularly heat-stabilized polyamide.

[0131] Advantageously, the polyamide is selected from among semi-aromatic polyamides.

[0132] In this second modification, the pre-impregnation is carried out by continuous passage of the fibers, particularly at high speed, in a fluidized bed or in an aqueous dispersion of the non-reactive thermoplastic polymer powder, or an aqueous dispersion of the thermoplastic polymer particles, or an emulsion or aqueous suspension of the non-reactive thermoplastic polymer, using a system selected from powdering (gravity deposition of dry powder) and spraying with a spray gun.

[0133] Advantageously, if pre-impregnation is performed by spraying with a spray gun, the intentional electrostatic method is eliminated.

[0134] Advantageously, this second modification includes at least one step of heating the pre-impregnated fiber material without support.

[0135] In this second variation, the pre-impregnation, carried out with powder, powder dispersion, emulsion, or suspension, is particularly necessary to dry the powder deposited by the dispersion, emulsion, or suspension, and / or to terminate or begin terminating the impregnation.

[0136] Advantageously, the second variation comprises at least one heating step performed using at least one support component (E) and at least one heating system, wherein the roving is in contact with part or all of the surface of the at least one support component (E) and scrolls with part or all of the surface of the heating system.

[0137] This heating process, performed by at least one support component (E), makes it possible to complete impregnation that would not be completed after heating without support.

[0138] If the pre-impregnation step is performed with a powder dispersion, emulsion, or suspension, an unsupported heating step is required to dry the pre-impregnated roving and complete the impregnation. A heating step performed using at least one support component (E) is optional in that case.

[0139] If the pre-impregnation step is performed by a fluidized bed or by spraying with a spray gun, an unsupported heating step is required to begin the completion of the impregnation, i.e., to begin melting the thermoplastic polymer on the fibrous material. A heating step performed using at least one support component (E) is then performed to complete the impregnation.

[0140] It is clear that the two heating processes can be carried out successively, that is, in two separate furnaces, or in the same furnace containing both systems.

[0141] Advantageously, the heating system for the unsupported or supported heating process can be selected from infrared lamps, UV lamps, convection heating, microwave heating, laser heating, and high-frequency (HF) heating.

[0142] It is clear that the two heating systems may be the same or different.

[0143] When the heating system is selected from infrared valves, UV valves, and convection heating, the support components are heated and conduct heat.

[0144] When the heating system is selected from microwave heating, laser heating, or high-frequency (HF) heating, the support components do not heat up and do not conduct heat.

[0145] Advantageously, heated calendars are excluded from the definition of heating systems that use support components.

[0146] Advantageously, in the second variation, the pre-impregnation is carried out by spraying with a fluidized bed, a nozzle, or a spray gun, and in particular by a fluidized bed, it is carried out in a tank equipped with at least one support component (E').

[0147] In one embodiment of the second variation described above, the method is: - A step to obtain a pre-impregnated fiber material by pre-impregnating a fiber material with at least one non-reactive thermoplastic polymer by spraying with a nozzle or spray gun through a fluidized bed in a tank equipped or not equipped with at least one support component (E') and through a drying path in a tank equipped or not equipped with at least one support component (E'), wherein the pre-impregnation step is performed with at least one non-reactive thermoplastic polymer, the number average molecular weight Mn of the thermoplastic polymer is 14,000 to 25,000, preferably 15,000 to 21,000, the melt viscosity of the thermoplastic polymer is 150 to 1500 Pa·s at a temperature of Tg + 220°C, preferably 200 to 750 Pa·s, the thermoplastic polymer is a polymer having Tg ≥ 130°C, and the pre-impregnated fiber material is heated without support to obtain the pre-impregnated fiber material. - A step of obtaining an impregnated fiber material by heating using at least one support component (E) and at least one heating system, - A step of obtaining an impregnated fiber material by heating using at least one support component (E) and at least one heating system, - Optionally, the process includes shaping and calibrating the roving or parallel roving of the impregnated fiber material to obtain an impregnated fiber material consisting of a ribbon in the form of a thin band.

[0148] In another embodiment of the second modification described above, the method comprises the following steps: - A step of pre-impregnating a fiber material with at least one non-reactive thermoplastic polymer, particularly by continuous passage of the fiber through a fluid bed of a dry polymer powder, an aqueous dispersion of polymer powder, an aqueous dispersion of polymer particles, or an emulsion or aqueous suspension of polymer, wherein the pre-impregnation step is carried out with at least an amorphous or semi-crystalline thermoplastic polymer, the thermoplastic polymer having a Tg ≥ 130°C, the non-reactive thermoplastic polymer having a number-average molecular weight Mn of 14,000 to 25,000, preferably 15,000 to 21,000, and the melt viscosity of the thermoplastic polymer being measured by planar-planar rheology at 1 Hz and 2% deformation, at a temperature of Tg + 220°C, is 150 to 1500 Pa·s, preferably 200 to 750 Pa·s. - A step of heating the pre-impregnated fiber material without support to obtain the pre-impregnated fiber material, - Optionally, a step of heating using at least one support component (E) and at least one heating system defined above to obtain an impregnated fiber material, - Optionally, the process includes shaping and calibrating the roving or parallel roving of the impregnated fiber material to obtain an impregnated fiber material consisting of a ribbon in the form of a thin band.

[0149] Advantageously, the present invention relates to a method for producing an impregnated fibrous material as defined above, characterized in that one or more supports (E) are present upstream of the system.

[0150] The phrase "upstream of the system" means that the support (E) is present before the pre-impregnation process.

[0151] Advantageously, the present invention relates to a method for producing the impregnated fiber material defined above, characterized in that the method is carried out at a speed of at least 5 to 30 m / min for the dry powder route and at least 15 m / min for the aqueous dispersion route.

[0152] Method for manufacturing impregnated fiber material In particular, the impregnated fiber material in a single layer can be manufactured in two or three of the steps described above, including optional molding and calibration steps.

[0153] The first step can be carried out by pre-impregnation of the fiber material or by impregnation of the fiber material.

[0154] Step 1: Pre-impregnation The first step of pre-impregnation for producing pre-impregnated fiber material can be carried out by techniques well known to those skilled in the art and selected in particular from those disclosed above.

[0155] Therefore, this can be carried out by pre-impregnation techniques by spraying with a nozzle or spray gun, by powder deposition, by continuous passage of fibers in an aqueous polymer powder dispersion or aqueous polymer particle dispersion or in an aqueous polymer emulsion or suspension, by a fluidized bed equipped with or not equipped with at least one support (E'), by a drying path in a tank equipped with or not equipped with at least one support (E').

[0156] Fluidized bed: The pre-impregnation process can be carried out in a fluidized bed.

[0157] An exemplary apparatus for carrying out a manufacturing method without a heating step using at least one support component is described in WO2015 / 121583.

[0158] This system describes the use of a tank containing a fluidized bed for performing a pre-impregnation process, which can be used in the present invention.

[0159] Another exemplary apparatus for a manufacturing method in which a support is present in a tank but without a heating step using at least one support component is described in WO2018 / 115736.

[0160] Advantageously, the tank containing the fluidized bed is equipped with at least one support component (E'), which may be a compression roller.

[0161] Support component (E') should be understood to mean any system through which the roving can move within the tank. Support component (E') may be of any shape as long as the roving can pass through it.

[0162] It should be noted that support components (E) and (E') may be identical or different in terms of material, shape, and their properties (diameter, length, width, height, etc., depending on the shape).

[0163] However, the support component (E') is neither heated nor subjected to heating.

[0164] The process for pre-impregnating the fibrous material is carried out by passing one or more rovings through a continuous pre-impregnation apparatus which includes a tank (10) having at least one support component (E') and containing a fluid powder bed (12) of the polymer matrix.

[0165] The polymer matrix or polymer powder is introduced into the tank via a hopper (11) and suspended in gas G (e.g., air) circulating within the tank (10). The roving circulates within this fluidized bed (12).

[0166] The tank can have any shape, particularly a cylinder or parallelepiped, especially a rectangular prism or a cube, and preferably a rectangular prism.

[0167] The tank (10) can be an open-type or closed-type tank.

[0168] If the tank is a closed type, a sealing system is provided to prevent the polymer matrix powder from leaving the tank.

[0169] Therefore, this pre-impregnation process is carried out via a drying route, meaning the thermoplastic polymer matrix is ​​in the form of a powder suspended in gas, particularly air, but cannot be dispersed in a solvent or water.

[0170] Each roving to be pre-impregnated is unwinded from the device on a reel under the traction force generated by a cylinder (not shown).

[0171] Each reel is equipped with a brake (not shown) to apply tension to each fiber roving. In this case, the adjustment module allows the fiber rovings to be positioned parallel to each other. In this way, the fiber rovings cannot come into contact with each other, thus avoiding mechanical damage to the fibers due to friction.

[0172] The fiber roving or parallel fiber roving then enters a tank (10), which contains a fluidized bed (12) equipped with support components (E'), particularly compression rollers (24). The fiber roving or parallel fiber roving then exits the tank after optionally checking the residence time in the powder following pre-impregnation.

[0173] The expression "residence time in the powder" refers to the time that the roving is in contact with the powder in the fluidized bed.

[0174] If the fibrous material, such as glass, basalt, or carbon fiber roving, has sizing, an optional desizing step can be performed before the fibrous material passes through the tank.

[0175] Advantageously, the tank used comprises a fluidized bed having a support, and the pre-impregnation process is carried out along with the simultaneous expansion of the roving between the inlet and outlet of the tank having the fluidized bed.

[0176] The expression "inlet to the tank" corresponds to the vertical tangent to the edge of the tank containing the fluidized bed.

[0177] The expression "outlet of the tank" corresponds to the perpendicular tangent to the other end of the tank containing the fluidized bed.

[0178] The expansion involves isolating each fiber constituting the roving from as many other fibers surrounding it in the nearest space as possible, and corresponds to the expansion of the roving in the transverse direction.

[0179] In other words, the width of the transverse separation or roving increases between the inlet and outlet of the tank containing the fluidized bed, thus enabling improved pre-impregnation of the fibrous material.

[0180] Therefore, the use of at least one support (E'), particularly a cylindrical compression roller, in the pre-impregnation process enables improved pre-impregnation compared to methods from the prior art.

[0181] The term "compression roller" means that the roving passing through is pressed partially or entirely against the surface of the compression roller, which causes the roving to expand.

[0182] Advantageously, the at least one compression roller is cylindrical, and the expansion ratio of the roving between the inlet and outlet of the fluidized bed tank is 1% to 1000%, preferably 100% to 800%, preferably 200% to 800%, and preferably 400% to 800%.

[0183] The percentage of expansion is equal to the ratio of the final width of the roving to the initial width of the roving multiplied by 100.

[0184] The diameter of the at least one compression roller is 3 mm to 500 mm, preferably 10 mm to 100 mm, and particularly 20 mm to 60 mm.

[0185] If the thickness is less than 3mm, the deformation of the fibers caused by the compression roller is too great.

[0186] Advantageously, the compression rollers are cylindrical, not ribbed, and are especially made of metal.

[0187] When the support component (E') is at least one compression roller, according to the first deformation, a single compression roller is present in the fluid bed, and the pre-impregnation is performed at an angle α1 formed by the roving between the inlet of the compression roller and the vertical tangent to the compression roller.

[0188] The angle α1 formed by the roving between the inlet of the compression roller and the perpendicular tangent to the compression roller causes the powder to concentrate, and thus the simultaneous expansion of the roving by the compression roller creates a region that produces a "corner effect," enabling pre-impregnation to a larger roving width, and therefore improved pre-impregnation compared to the improved background technology.

[0189] Throughout this specification, all angle values ​​provided are expressed as absolute values.

[0190] Advantageously, the angle α1 is 0 to 89°, preferably 5° to 85°, preferably 5° to 45°, and preferably 5° to 30°.

[0191] Nevertheless, angles α1 of 0-5° can create a risk of mechanical stress leading to fiber breakage, while angles α1 of 85-89° do not generate sufficient mechanical force to create a "corner effect."

[0192] Therefore, the angle α1 value equal to 0° corresponds to vertical fibers. The height of the cylindrical compression roller is adjustable, and thus it is clear that it is possible to position the fibers vertically.

[0193] Advantageously, the inlet end (23a) of the tank is equipped with rollers, particularly cylindrical and rotating rollers, over which the roving passes, thus causing expansion prior to pre-impregnation.

[0194] The “corner effect” caused by angle α1 enhances pre-impregnation on one surface, but it is clear that the expansion of the roving obtained by the compression roller also allows for pre-impregnation on other surfaces of the roving. In other words, the pre-impregnation is enhanced on one surface of the roving near the angle α1 formed by the roving between the entry point to the at least one compression roller R1 and the perpendicular tangent to the compression roller R1, but the expansion also allows for pre-impregnation on other surfaces.

[0195] The angle α1 is as defined above.

[0196] Advantageously, the volume diameter D90 of the thermoplastic polymer powder particles is 30-500 μm, and advantageously 80-300 μm.

[0197] Advantageously, the volume diameter D10 of the thermoplastic polymer powder particles is 5 to 200 μm, and more advantageously, 15 to 100 μm.

[0198] Advantageously, the volume diameter of the thermoplastic polymer powder particles is in a ratio D90 / D10, or 1.5 to 50, advantageously 2 to 10.

[0199] Advantageously, the average volume diameter D50 of the thermoplastic polymer powder particles is 10–300 μm, particularly 30–200 μm, and more specifically 45–200 μm.

[0200] The volume diameters of the particles (D10, D50, and D90) are defined according to the standard ISO 9276:2014.

[0201] "D50" corresponds to the average diameter by volume, that is, the particle size value that accurately divides the inspected group of particles in half.

[0202] "D90" corresponds to the value at 90% of the cumulative curve of the particle size distribution by volume.

[0203] "D10" corresponds to a size of 10% of the particle's volume.

[0204] According to other modifications, two or more rollers can be present in the fluidized bed.

[0205] Spraying with a spray gun: Another exemplary apparatus for a manufacturing method in which a support is present in a tank but without a heating step using at least one support component is described in WO2018 / 115737.

[0206] The pre-impregnation process of the fiber material can also be carried out by spraying, which includes a tank containing one or more nozzles or one or more guns that spray polymer powder of the fiber material at the roller inlet, by feeding one or more rovings into a continuous pre-impregnation apparatus.

[0207] The powder from the polymer is sprayed onto the fibrous material in the tank, particularly by a nozzle or spray gun near the support components of the compression roller (at the inlet). The roving circulates within this tank.

[0208] The corner effect is caused, and while the details for fluid beds are described, all the properties of the support, especially the compression rollers, expansion, and angle α1 are also effective for spraying with a spray gun.

[0209] According to other variations, there may be two or more rollers, each having its own spray gun.

[0210] Step 1: Impregnation The first impregnation step for producing impregnated fiber materials is well known to those skilled in the art and can be carried out by techniques selected from those disclosed above.

[0211] Therefore, this can be done by the melting path of the molten polymer, particularly by pultrusion, and by crosshead die extrusion.

[0212] The pre-impregnation process is carried out by crosshead die extrusion of the polymer matrix and passage of the roving through the crosshead die, followed by passage through a heated die, the crosshead die optionally equipped with a stationary or rotating support over which the roving passes, thus spreading the roving and enabling pre-impregnation of the roving.

[0213] Impregnation can be carried out as described in particular in US2014 / 0005331A1, the difference being that the resin is supplied on both sides of the roving and there is no contact surface that removes a portion of the resin on one of the two surfaces.

[0214] Advantageously, the impregnation process is carried out at high speed through the melting path, particularly at a speed of at least 1 to 10 m / min in the melting path, and especially at a roving passage speed of at least 2 m / min.

[0215] Step 2: Heating and drying of pre-impregnated fiber material without support. As already noted above, this heating process without a support allows for drying rovings that have been pre-impregnated with a dispersion, suspension, or emulsion, and enables the impregnation to be started or terminated based on the length of the furnace, including the heating system.

[0216] The heating system enables the melting of the thermoplastic polymer to be impregnated into the fibrous material.

[0217] The heating system is particularly an IR, microwave, high-frequency, or laser heating system, and more particularly an IR heating system having an output of 0.1W to 10kW, more preferably 0.1 to 6kW, more preferably 0.1 to 3kW, even more preferably 0.6 to 3kW, and even more preferably 0.6 to 1.8kW.

[0218] Optional third step: Completion of heating and impregnation using a support of pre-impregnated fiber material. Therefore, the pre-impregnation process can be carried out by any available means or without using at least one support (E').

[0219] The presence of a support allows for roving expansion and improves pre-impregnation. However, the presence of this support is not essential as long as there is a heating system with at least one support component (E) that completes the impregnation after the pre-impregnation process.

[0220] The term "support component (E)" refers to any system through which the roving can pass. As long as the roving can pass through it, the support component (E) can have any shape and may be stationary or rotating.

[0221] A heating system is any system that emits heat or radiation that can heat a support component (E).

[0222] It can be selected from infrared lamps, UV lamps, convection heating, microwave heating, laser heating, and high-frequency (HF) heating.

[0223] The heating system enables the melting of the thermoplastic polymer to be impregnated into the fibrous material.

[0224] The heating system is particularly an IR, microwave, high-frequency, or laser heating system, and more particularly an IR heating system having an output of 0.1W to 10kW, more preferably 0.1 to 6kW, more preferably 0.1 to 3kW, even more preferably 0.6 to 3kW, and even more preferably 0.6 to 1.8kW.

[0225] Therefore, the support component (E) is either conductive or absorbs radiation emitted by heat.

[0226] The expression "thermally conductive support component (E)" means that the support component (E) is made of a material that can absorb and conduct heat.

[0227] It may also be a heating system that uses high frequency, microwave, or laser.

[0228] In this case, the support component does not conduct heat or absorb radiation emitted by the heat.

[0229] The term "non-thermal-conducting support component (E)" means that the support component (E) is made of a material that cannot absorb or conduct heat.

[0230] The at least one support component (E) is located within or included in the environment of the heating system, i.e., not outside the heating system.

[0231] Advantageously, the heating system is mounted on the at least one support component (E). The heating system has a sufficient level to melt the polymer present on the roving without damaging the polymer.

[0232] Nevertheless, the heating system may include only the at least one support component (E), or it may include a portion of a roving located outside the support system (E), the portion of which is positioned before and / or after the support system (E).

[0233] The height between the heating system and the support is 1 to 100 cm, preferably 2 to 30 cm, and especially 2 to 10 cm.

[0234] Even if the support component (E) is located within a furnace including a heating system, such as an IR heating system, but is not located directly beneath a heating element, such as an IR heating element, this would not be outside the scope of the present invention. If the furnace includes both a convection heating mode and an IR heating system, this would not be outside the scope of the present invention.

[0235] Furthermore, if the support component (E) located in the furnace or the environment of the furnace is equipped with autonomous heating means, such as a resistor, that enables heating of the support component (E) independently of irradiation from an IR lamp and natural convection of the furnace, and if the polymer present in the ribbon or roving is in a molten state when it arrives in contact with the support component at line speed, then the present invention would not be outside its scope.

[0236] The height between the heating system and the support is 1 to 100 cm, preferably 2 to 30 cm, and especially 2 to 10 cm.

[0237] It is clear that a second heating system can be present beneath the support, thereby enabling uniform melting of the polymer on the two surfaces of the roving.

[0238] The heating system may be horizontal. However, the heating system can also be positioned vertically, with the roving passing vertically through the support.

[0239] As a result, this heating process completes the impregnation of the roving that was carried out in advance during the pre-impregnation process, making it possible to obtain uniform impregnation, especially to the core.

[0240] In fact, whatever system is used in the pre-impregnation process, especially if the pre-impregnation process is carried out using a support component (E') in a fluidized bed having at least one support, such as the one described above, the first expansion occurs during this process.

[0241] The first expansion of the roving occurs with the “corner effect” resulting from the partial or complete passage of the roving over the support component (E') by the compression roller corresponding to the support component (E'), and the second expansion occurs during the heating process due to the partial or complete passage of the roving over the support component (E) by the compression roller corresponding to the support component (E).

[0242] The heating system can be divided into two, and thus consist of two heating systems: a first heating system in front of the support component (E), and a second heating system including the support component. It is quite obvious that the distance between the two heating systems is sufficient in that case for the polymer to remain in a molten state.

[0243] The two heating systems may be of the same type or different types, and may have the same or different outputs.

[0244] This second expansion occurs during the passage of the roving through the heating system, prior to its partial or complete passage over the support (E), following the contraction of the roving due to the melting of the polymer on the roving.

[0245] This heating system, combined with the melting of the polymer matrix and the pulling back of the rovings, results in a second expansion which homogenizes the pre-impregnation and thus completes the impregnation, thus impregnating the core and having a certain high fiber volume content, particularly at least 70%, particularly at least 80%, particularly at least 90%, and more specifically at least 95% of the ribbon's volume, as well as reducing porosity.

[0246] Advantageously, the inlet of the first compression roller R'1 and the last compression roller R' during the heating process i The expansion rate between the exit and the exit is approximately 0-300%, particularly 0-50%.

[0247] The melting of the thermoplastic polymer and the shrinkage of the roving during the heating process, combined with various expansions during the heating process, make it possible to produce a post-heating impregnated fiber content of 45% to 65% by volume, preferably 50% to 60% by volume, and especially 54% to 60% (a fiber content that cannot be achieved by traditional techniques via the melting route), where the fiber volume content and fiber distribution are substantially identical on average over the full length of the fiber material on either side of the midline of the fiber material, thus particularly leading to the acquisition of a single-layer fiber material.

[0248] For fibers with less than 45% content, reinforcement is not of interest in terms of mechanical properties.

[0249] Beyond 65%, the method reaches its limits, and the mechanical properties are lost again.

[0250] Advantageously, the porosity level of the impregnated fiber material is less than 10%, particularly less than 5%, and particularly less than 2%.

[0251] Molding and calibration process: process for obtaining a thin band. The steps of forming the roving or the parallel roving and calibrating the impregnated fiber material can be performed after exiting the second heating system.

[0252] This process can be performed immediately after exiting the second heating system, in which case the roving's travel speed will be the same or slower in the second and third heating systems, meaning that the roving's travel speed may differ between the second and third heating systems.

[0253] This process can be carried out according to one of the following embodiments: 1) The impregnated band is passed over one or more supports (as defined for (E)) of which at least one is notched (grooved), and the average width of the strip is less than that of the notched (or grooved) supports.

[0254] At least one of the supports is positioned beneath a third heating system, particularly an IR, microwave, radio frequency, or laser heating system, particularly an IR heating system, having an output of 0.1W to 10kW, more preferably 0.1 to 6kW, more preferably 0.1 to 3kW, even more preferably 0.6 to 3kW, and even more preferably 0.6 to 1.8kW (for each stack of ribbons or parallel ribbons). Advantageously, the at least one notched roller (41) is positioned first and outside the third heating system (45). Advantageously, a second notched support (44) is located at the outlet and outside the third heating system.

[0255] Passing over the non-notched supports (42) and (43) allows the strip to be widened again to the width of the notched supports.

[0256] The diameters of the notched supports (41) and (44) are 12 mm to 50 mm, and especially 12 mm to 30 mm.

[0257] The diameters of the non-notched supports (42) and (43) are 10 mm to 50 mm, and especially 10 mm to 30 mm.

[0258] After passing under the third heating system, the band, formed to the width of a notched support at the outlet of the third heating system, passes through the level of a heating calendar (46) equipped with 1 kW IR systems mounted in series, the output delivered being variable to obtain a calibrated thin band, and is located outside the third heating system.

[0259] 2) The band passes over one or more supports (as defined for (E)) where at least one of them is notched (grooved), and the average width of the band is greater than that of the notched (or grooved) supports.

[0260] The support is placed beneath a third heating system, particularly an IR, microwave, radio frequency, or laser heating system, particularly an IR heating system, having an output of 0.1W to 10kW, more preferably 0.1 to 6kW, more preferably 0.1 to 3kW, even more preferably 0.6 to 3kW, and even more preferably 0.6 to 1.8kW (for each ribbon or parallel ribbon stacking).

[0261] Advantageously, the at least one notched roller is positioned first.

[0262] Passing over the first notched support allows for a reduction in the width of the strip if it is smaller than the width of the notched groove. Advantageously, the second notched support is located outside the third heating system, at the exit, and has a groove wider than the width of the strip.

[0263] After passing under the third heating system, the strip, formed to the width of the notched support at the outlet of the third heating system, passes at the level of a heating calendar equipped with a 1kW IR system mounted in series, outside the third heating system, to obtain a calibrated thin band.

[0264] A calendering system with controlled pressure and roll gap, as disclosed in WO2015 / 121583, can be used in both of these embodiments.

[0265] The support is a roller with fixed or rotating notches, or even a reverse-rotating roller, in particular a fixed roller for gathering the impregnated fiber material to the correct width.

[0266] To avoid damaging the fibers at the ends of the thin band, the notched roller may also have rounded ends at the lateral contact points with the support.

[0267] The expression "rounded edge" means that the bottom of the cut is concave or convex in shape.

[0268] Advantageously, the first embodiment of the molding and calibration process is preferred.

[0269] Therefore, this allows for operation at a high speed of movement, and thus lowers production costs.

[0270] In another aspect, the present invention relates to the use of, for example, the impregnated fiber material defined above, for the manufacture of ribbons suitable for the manufacture of three-dimensional composite parts by the automatic application of the ribbons by a robot.

[0271] Furthermore, all the properties defined above for fibrous materials are effective for the aforementioned uses.

[0272] In another aspect, the present invention relates to the use of the above-defined impregnated fiber material for the manufacture of a thermoformable sheet.

[0273] Furthermore, all of the properties defined above for the fibrous material are effective for the aforementioned use.

[0274] Advantageously, the impregnated fiber material used in the foregoing is pre-cut into fragments, which are then randomly linked or oriented for the production of a thermoformable sheet.

[0275] Thermoforming is carried out above Tg for amorphous thermoplastic polymers, or between Tg and Tm for semicrystalline thermoplastic polymers; however, it can also be carried out above Tm for semicrystalline thermoplastic polymers.

[0276] The impregnated fiber material is pre-cut into elongated pieces having a width equal to the initial width of the fiber material and a length of 5 to 50 mm, particularly 20 to 30 mm, and the pieces are randomly linked or oriented for the production of a thermoformable sheet.

[0277] According to another aspect, the present invention relates to the use of at least one non-reactive thermoplastic polymer, said at least one non-reactive thermoplastic polymer being an amorphous or semi-crystalline thermoplastic polymer having a glass transition temperature of Tg≧40°C, particularly Tg≧100°C, particularly ≧120°C, said thermoplastic polymer having a number average molecular weight Mn of the thermoplastic polymer of 11,000 to 25,000 g / mol, and the melt viscosity of said thermoplastic polymer being 80 to 1500 Pa·s when measured by plane-plane rheology at 1 Hz and 2% deformation and at a temperature of Tg + 220°C for impregnating the fibrous material as defined above.

[0278] Also, all the properties of the fibrous material defined above are effective for said use.

[0279] Advantageous embodiments of the inventive method Advantageously, the fibrous material is selected from carbon fiber rovings, particularly 12K or more, particularly 12K, 24K, 48K, 50K and 400K, particularly 12K, 24K, 48K and 50K, and glass fibers, particularly having a basis weight of 1,200 tex or more, particularly 2,400 tex or more, 4,800 tex or more.

[0280] Advantageously, the thermoplastic prepolymer used for impregnating the carbon fibers is selected from polyamides, particularly aliphatic polyamides such as PA 11, PA 12, PA 11 / 1010 and PA 12 / 1010, semi-aromatic polyamides, particularly PA MPMDT / 6T, PA PA11 / 10T, PA 11 / BACT, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA 11 / BACT / 6T, PA 11 / MPMDT / 10T PA 11 / BACT / 10T, PA 11 / MXDT / 10T, PEKK, PEEK and PEI, or mixtures thereof.

[0281] Advantageously, the thermoplastic prepolymer used to impregnate the glass fibers is selected from polyamides, particularly aliphatic polyamides such as PA 11, PA 12, PA 11 / 1010 and PA 12 / 1010, semi-aromatic polyamides, in particular PA MPMDT / 6T, PA PA11 / 10T, PA 11 / BACT, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA 11 / BACT / 6T, PA 11 / MPMDT / 10T, PA 11 / BACT / 10T, PA 11 / MXDT / 10T, PEKK, PEEK and PEI, or mixtures thereof.

[0282] Advantageously, the fiber material includes carbon fiber roving selected from 12K or higher, particularly 12K, 24K, 48K, 50K and 400K, and the thermoplastic polymer used to pre-impregnate the carbon fiber is polyamide, particularly aliphatic polyamide, e.g., PA 11, PA 12, PA 11 / 1010 and PA 12 / 1010, semi-aromatic polyamide, particularly PA MPMDT / 6T, PA 11 / 10T, PA 11 / BACT, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA 11 / BACT / 6T, PA 11 / MPMDT / 10T, PA 11 / BACT / 10T, PA Selected from 11 / MXDT / 10T, PEKK, PEEK, and PEI, or a mixture thereof.

[0283] Advantageously, the fiber material includes carbon fiber roving selected from 12K or higher, particularly 12K, 24K, 48K, 50K and 400K, and the thermoplastic polymer used to pre-impregnate the carbon fiber is polyamide, particularly aliphatic polyamide, e.g., PA 11, PA 12, PA 11 / 1010 and PA 12 / 1010, semi-aromatic polyamide, particularly PA MPMDT / 6T, PA 11 / 10T, PA 11 / BACT, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA 11 / BACT / 6T, PA 11 / MPMDT / 10T, PA 11 / BACT / 10T, PA It consists of 11 / MXDT / 10T, PEKK, PEEK, and PEI, or a mixture thereof.

[0284] Advantageously, the fibrous material comprises glass fibers having a basis weight of 1,200 tex or more, particularly 2,400 tex or more, and 4,800 tex or more, and the thermoplastic polymer used to pre-impregnate the glass fibers is selected from polyamides, particularly aliphatic polyamides, such as PA 11, PA 12, PA 11 / 1010 and PA 12 / 1010, semi-aromatic polyamides, particularly PA MPMDT / 6T, PA PA11 / 10T, PA 11 / BACT, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA 11 / BACT / 6T, PA 11 / MPMDT / 10T, PA 11 / BACT / 10T, PA 11 / MXDT / 10T, PEKK, PEEK and PE or mixtures thereof.

[0285] Advantageously, the fibrous material consists of glass fibers having a basis weight of 1,200 tex or more, particularly 2,400 tex or more, and 4,800 tex or more, and the thermoplastic polymer used to pre-impregnate the glass fibers is polyamide, particularly aliphatic polyamide, e.g., PA 11, PA 12, PA 11 / 1010 and PA 12 / 1010, semi-aromatic polyamide, particularly PA MPMDT / 6T, PA PA11 / 10T, PA 11 / BACT, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA 11 / BACT / 6T, PA 11 / MPMDT / 10T, PA 11 / BACT / 10T, PA It consists of 11 / MXDT / 10T, PEKK, PEEK, and PEI, or a mixture thereof. [Brief explanation of the drawing]

[0286] [Figure 1] This image shows the morphology of a fully impregnated composite plate with microcracks, obtained from an excessively low molecular weight Mn=10,500 g / mol 11 / 10T / 6T polymer with a melt viscosity of 70 Pa·s at 330°C (planar / planar rheology, 1 Hz, and 2% deformation). The scale bar represents 50 μm. [Figure 2] The morphology of a composite panel exhibiting the same microcracks as in Figure 1 is shown at a higher magnification. The scale bar represents 20 μm. [Figure 3] This image shows the morphology of a composite plate with a dry fibrous region, obtained from an excessively high molecular weight Mn=27,200 g / mol 11 / 10T / 6T polymer, having a melt viscosity of 1790 Pa·s at 330°C (planar-planar rheology, 1 Hz, and 2% deformation). The scale bar represents 100 μm. [Figure 4] The morphology of the same composite panel as in Figure 3, which has a dry region, is shown at a higher magnification. The scale bar represents 20 μm. [Figure 5]This paper shows the morphology of a composite plate obtained from an 11 / 10T / 6T polymer with a molecular weight Mn = 13,700 g / mol, having a melt viscosity of 185 Pa·s at 330°C (planar-planar rheology, 1 Hz and 2% deformation at Tg + 220°C), without microcracks or dry regions, demonstrating the optimal molecular weight of the polymer. The scale bar represents 200 μm. [Figure 6] The morphology of the same composite panel as in Figure 5, without microcracks or dry areas, is shown at a higher magnification. The scale bar represents 20 μm. [Examples]

[0287] The following embodiments provide non-limiting examples of the scope of the present invention.

[0288] Example 1 (Comparative Example): Impregnation of fiber materials using type 11 / 10T / 6T PA with Tg 110℃, mass Mn = 10,500 g / mol, and melt viscosity of 70 Pa·s at 330℃ (planar / planar rheology, 1 Hz and 2% deformation).

[0289] The polymer was ground into a powder with an average diameter D50 = 110 μm, and then processed at 400 g / m². 2 In the form of UDT (UD tape), powder is deposited by gravity onto the surface of a woven 3B Advantex SE4535 glass fiber reinforced material: Since 90% of the fibers are in the weft direction, this type of reinforcement is semi-UD (unidirectional fiber).

[0290] The assembly is heated by infrared heating to solidify the powder.

[0291] The powder level is 30% by weight (or 50% by volume).

[0292] The prepreg obtained in this way is cut into 300*200mm sheets, and four of these sheets are stacked to form a preform. This preform is then integrated using a CARVER press at 330°C for 15 minutes, then cooled and removed from the mold at 100°C.

[0293] According to Standard 14125 (1998), bend test specimens are taken in the minor direction of the fibers (90° orientation) and tested.

[0294] The results are provided in Table I below. In the bending obtained using a mass of 10,500, a fracture stress value of 40 MPa is considered insufficient to protect against the presence of premature microcracks in the composite material at the fiber - resin contact surface in the presence of mechanical or thermal loads.

[0295] This result is obtained despite the perfect impregnation of the fibers, but the presence of microcracks can be observed in the plates (see Figure 1), appears upon cooling under the influence of thermal stress, and affects the strength of the obtained composite material: in this case, it was concluded that the molecular weight of the polymer used was insufficient.

[0296] Example 2 (Comparative Example): Impregnation according to Example 1 of a fiber material using PA of type 11 / 10T / 6T having a Tg of 110 °C, a mass Mn = 27,200 g / mol, and a melt viscosity of 1790 Pa·s at 330 °C (parallel - parallel rheology, 1 Hz and 2% deformation).

[0297] The properties of the fiber reinforcement, the method of manufacturing the prepreg, the composite plate, and the mechanical test protocol are the same as those in Example 1.

[0298] The results obtained by transverse bending (90°) according to ISO 14125 (1998) are shown in Table I: it is close to that obtained using the low - mass polymer of Example 1; this proves that at this time the mass of the polymer is too high and hinders good impregnation of the fibers, which is observed by the presence of resin - free dry zones in the integrated plate (see Figure 2).

[0299] Since the Mn of the polymer is too high, it has too high a viscosity, and thus its impregnation causes dry zones.

[0300] Example 3: Impregnation of fiber materials using type 11 / 10T / 6T PA with Tg 110℃, mass Mn = 13,700 g / mol, and melt viscosity of 185 Pa·s at 330℃ (planar / planar rheology, 1 Hz and 2% deformation at Tg + 220℃).

[0301] The properties of the fiber reinforcement material, the manufacturing method of the prepreg, the composite board, and the mechanical testing protocol are the same as those of Example 1.

[0302] When the molecular weight of the resin increases from 10,500 to 13,700, a clear improvement in the transverse mechanical properties (90°) is observed according to ISO 14125 (1998).

[0303] The morphology of the plate (see Figure 3) differs from that of Comparative Examples 1 and 2, showing that there are no microcracks or drying zones within the plate, demonstrating that the polymer molecular weight is optimal.

[0304] Example 4 Impregnation of a fibrous material using PA of type MPMDT / 10T (67 / 33 mol%) with D50 = 115 μm and Tg 125°C. Its mass is 14,000 g / mol (measured by NMR), and its melt viscosity (planar / planar rheology, 1 Hz and 2% deformation at Tg + 220°C) is 214 Pa·s at 345°C.

[0305] The polymer is ground into a powder having an average diameter D50 = 115 μm. The powder is supplemented with a dry blend containing a heat stabilizer, and then 400 g / m³ is added according to Example 1. 2 The powder is deposited on the surface of woven, 3B Advantex glass-reinforced fiber SE4535 in the form of UDT (90% of the fiber is in the weft direction and 10% is in the warp direction): the powder level is 30% by weight (or 50% by volume).

[0306] The prepreg obtained in this way is cut into 300*200mm sheets, and four of these sheets are stacked to form a preform. This preform is then integrated using a CARVER press at 345°C for 15 minutes, then cooled, and removed from the mold at 100°C.

[0307] In accordance with the ISO 14125 (1998) standard, bending test specimens are taken in multiple directions of the fiber (weft direction) and tested.

[0308] The results are provided in Table I below.

[0309] It is observed that a satisfactory compromise can be reached between molecular weight and melt viscosity.

[0310] Example 5: Impregnation of a fiber material using type BACT / 10T PA with a Tg of 140°C. Its mass is 19,100 g / mol (measured by NMR), and its melt viscosity (planar-planar rheology, 1 Hz and 2% deformation at Tg + 220°C) is 502 Pa·s at 360°C.

[0311] The polymer is ground into a powder having an average diameter DN50 = 110 μm. The powder is supplemented with a dry blend containing a heat stabilizer, and then 400 g / m³ is added according to Example 1. 2 The powder is deposited on the surface of woven, 3B Advantex glass-reinforced fiber SE4535 in the form of UDT (90% of the fiber is in the weft direction and 10% is in the warp direction): the powder level is 30% by weight (or 50% by volume).

[0312] The prepreg obtained in this way is cut into 300*200mm sheets, and four of these sheets are stacked to form a preform. This preform is then integrated using a CARVER press at 360°C for 15 minutes, then cooled, and removed from the mold at 100°C.

[0313] In accordance with the ISO 14125 (1998) standard, bending test specimens are taken in multiple directions of the fiber (weft direction) and tested.

[0314] The results are provided in Table I below.

[0315] It is observed that a satisfactory compromise can be reached between molecular weight and melt viscosity.

[0316] Example 6: The polymer is MXD10 with a mass of 15,000 g / mol. Its Tg is 70°C and its viscosity at 290°C is 110 Pa·s.

[0317] The method for manufacturing the composite board is a pultrusion method that includes impregnation via a melting path using a crosshead die. The polymer is introduced in granular form, pre-mixed with a heat stabilizer in the extruder, and then supplied to the crosshead die.

[0318] The temperature at which the fibers were impregnated was 290°C.

[0319] The line speed was within the range of 1.1 m / min pb / claim.

[0320] The fiber used is Hypertex glass fiber 3B SE4535.

[0321] The fiber level was 60% by volume.

[0322] Excellent mechanical properties can be obtained by bending measurements according to the standard ISO 14125 (1998). These are summarized in Table I below:

[0323] In this embodiment, unlike other embodiments, no failure was observed in transverse bending up to a 10% deformation. If this value is exceeded, the test is terminated as it exceeds the conditions recommended in standard ISO 14125. In this case, the superiority of the transverse mechanical properties (i.e., the deformation value is achieved perpendicular to the fibers (90° direction)) is judged by the ductility of the resulting composite, thereby demonstrating a good compromise between melt viscosity and molecular weight. [Table 1] TIFF2026064993000001.tif59170

[0324] Examples 1 through 5 all resulted in failure.

[0325] Therefore, Example 6 corresponds to a material that deforms significantly without breaking.

[0326] Example 7: Determination of the relative deviation of porosity levels between theoretical and experimental densities (general method) a) Required data: - Density of thermoplastic matrix - Fiber density - Basis weight of reinforcing material: • For example, the line mass (g / m) for a 1 / 4-inch band (derived from a single roving) • For example, surface density (g / m²) for a wider band or fabric. 2 ) b) Measurements to be performed:

[0327] For the results to be representative of the materials examined, the sample size must be at least 30.

[0328] Measurements to be taken: - Size of the sample to be collected: • Length (if the line mass is known) • Length and width (if surface density is known) - Experimental density of samples to be collected: • Mass measurement in air and water - Fiber levels are measured according to ISO 1172:1999, or by thermogravimetric analysis (TGA) as determined, for example, in document B. Benzler, Applikationslabor, Mettler Toledo, Giesen, UserCom 1 / 2001.

[0329] The carbon fiber level can be determined according to ISO 14127:2008.

[0330] Determination of theoretical mass fiber levels: a) Determination of theoretical mass fiber levels: TIFF2026064993000002.tif14170 Here, m l is the linear mass of the tape, L is the length of the sample. Me air is the mass of the sample measured in air.

[0331] Variations in the mass fiber level are presumed to be directly related to variations at the matrix level without considering variations in the amount of fiber in the reinforcement. b) Determination of the theoretical density: TIFF2026064993000003.tif19170Here, d m and d f are the respective densities of the matrix and the fiber.

[0332] The theoretical density calculated in this way is the density that would be reached if there were no porosity in the sample. c) Evaluation of porosity:

[0333] Porosity is the relative deviation between the theoretical density and the experimental density.

Claims

1. An impregnated fibrous material comprising a fibrous material of at least one continuous fiber in the form of roving or several parallel rovings and at least one thermoplastic polymer matrix, wherein the at least thermoplastic polymer is an amorphous or semicrystalline polymer having a glass transition temperature such as Tg ≥ 40°C, particularly Tg ≥ 100°C, especially ≥ 120°C, as measured after a second heating using a differential scanning calorimeter (DSC) in accordance with standard ISO 11357-2:2013 with a heating rate of 20°C / min and a cooling rate of 20°C / min. The impregnated fiber material is characterized in that the fiber content in the impregnated fiber material is 45 to 65 volume%, preferably 50 to 60 volume%, particularly 54 to 60 volume%, the number average molecular weight Mn of the thermoplastic polymer is 11,000 to 25,000 g / mol, and the melt viscosity of the thermoplastic polymer is 80 to 1500 Pa·s, measured by planar / planar rheology at 1 Hz and 2% deformation, and at a temperature of Tg + 220°C.

2. The impregnated fiber material according to claim 1, characterized in that the polymolecular index Ip of the thermoplastic polymer is 2 to 6, particularly 2 to 3.5, and especially 2.5 to 3.

5.

3. The at least thermoplastic polymer is polyaryletherketone (PAEK), particularly poly(etheretherketone)(PEEK); polyaryletherketoneketone (PAEKK), particularly polyetherketoneketone (PEKK); aromatic polyetherimide (PEI); polyarylsulfone, particularly polyphenylenesulfone (PPSU); polyarylsulfide, particularly polyphenylenesulfide (PPS); polyamide (PA), particularly semi-aromatic polyamide (polyphthalamide) optionally modified with urea units. The impregnated fiber material according to claim 1 or 2, characterized in that it is selected from a mixture of PEKK and PEI in an amount of 90-10% to 60-40% by weight, particularly 90-10% to 70-30% by weight, in particular PEBA, polyacrylate, especially polymethyl methacrylate (PMMA); polyolefin, polylactic acid (PLA), polyvinyl alcohol (PVA), and fluorinated polymer, especially polytetrafluoroethylene (PTFE) or polychlorotrifluoroethylene (PCTFE); and mixtures thereof, particularly preferably 90-10% to 60-40% by weight, and especially 90-10% to 70-30% by weight.

4. The impregnated fiber material according to any one of claims 1 to 3, characterized in that the number average molecular weight Mn of the thermoplastic polymer is 14,000 to 25,000, preferably 15,000 to 21,000, the melt viscosity of the thermoplastic polymer is 150 to 1500 Pa·s, preferably 200 to 750 Pa·s at a temperature of Tg + 220°C, and the thermoplastic polymer is a polymer having Tg ≥ 130°C.

5. The impregnated fiber material according to claim 4, characterized in that the at least thermoplastic polymer is a polyamide, particularly a heat-stabilized polyamide.

6. The impregnated fiber material according to claim 5, characterized in that the polyamide is selected from semi-aromatic polyamides.

7. The aforementioned semi-aromatic polyamide is optionally modified with urea units, and selected from semi-aromatic polyamides of formula X / YAr, particularly semi-aromatic polyamides of formula A / XT, where A is selected from units obtained from amino acids, units obtained from lactams, and units corresponding to formula (Ca diamine) and (Cb diacid), where a represents the number of carbon atoms in the diamine and b represents the number of carbon atoms in the diacid, and a and b are each between 4 and 36, preferably between 9 and 18, and the unit (Ca diamine) is selected from linear or branched aliphatic diamines, alicyclic diamines, and alkyl aromatic diamines, and the unit (Cb diacid) is selected from linear or branched fatty diacids, alicyclic diacids, and aromatic diacids. X.T represents a unit obtained by polycondensation of Cx diamine and terephthalic acid, where x represents the number of carbon atoms in the Cx diamine, and x is between 6 and 36, preferably between 9 and 18, in particular formulas A / 6T, A / 9T, A / 10T or A / 11T (where A is as defined above), in particular polyamide PA6 / 6T, PA66 / 6T, PA6I / 6T, PAMXDT / 6T, PAMPMDT / 6T, PA11 / 10T, PA11 / 6T / 10T, PAMXDT / 10T, PAMPMDT / 10T, PABACT / 10T, PABACT / 6T, PA11 / BACT, PABACT / 10T / 6T, PA11 / BACT / 6T, PA11 / MPMDT / 6T, PA The fiber material according to claim 6, characterized in that it is 11 / BACT / 10T, PA 11 / MXDT / 10T, and PA 11 / MXDT / 6T.

8. The impregnated fiber material according to claim 6 or 7, characterized in that the semi-aromatic polyamide is selected from PA MXDT / 6T, PA MPMDT / 6T, PA 11 / BACT, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA 11 / BACT / 6T, PA 11 / MPMDT / 6T, PA 11 / BACT / 10T, PA 11 / MXDT / 10T, PA 11 / MXDT / 6T.

9. The impregnated fiber material according to any one of claims 1 to 3, characterized in that the number average molecular weight Mn of the thermoplastic polymer is 11,000 to 20,000 g / mol, preferably 12,000 to 18,000, the melt viscosity of the thermoplastic polymer is 80 to 650 Pa·s at a temperature of Tg + 220°C, preferably 100 to 450 Pa·s, and the thermoplastic polymer is a polyamide having Tg < 130°C.

10. The impregnated fiber material according to claim 9, characterized in that the polyamide having Tg < 130°C is selected from aliphatic polyamides, alicyclic polyamides, semi-aromatic polyamides, and especially aliphatic polyamides and alicyclic polyamides, all having a Tg of less than 130°C.

11. The aliphatic polyamide is selected from polyamide 6 (PA-6), polyamide 11 (PA-11), polyamide 12 (PA-12), polyamide 66 (PA-66), polyamide 46 (PA-46), polyamide 610 (PA-610), polyamide 612 (PA-612), polyamide 1010 (PA-1010), polyamide 1012 (PA-1012), polyamide 11 / 1010, polyamide 12 / 1010, or mixtures thereof or copolyamides thereof, and block copolymers, particularly polyamide / polyether (PEBA), and the semi-aromatic polyamide is selected from MXD10, MXD6, PA 6 / 6T, PA 66 / 6T, PA 6I / 6T, MPMDT / 10T, 11 / MPMDT / 10T, MPMDT / 6T, PA BACT / 10T, PA The impregnated fiber material according to claim 10, characterized in that it is selected from 11 / BACT / 10T, MXDT / 10, and PA 11 / MXDT / 10T.

12. The impregnated fiber material according to any one of claims 1 to 11, characterized in that the number of carbon fibers in the fiber material is 3K or more, particularly 6K or more, particularly 12K or more, particularly 12K, 24K, 48K, 50K and 400K, particularly 12K, 24K, 48K and 50K, or the basis weight of the glass fibers is 1,200 tex or more, particularly 2,400 tex or more, or 4,800 tex or more.

13. An impregnated fiber material according to any one of claims 1 to 12, characterized in that the fibers of the fiber material are not sized.

14. An impregnated fiber material according to any one of claims 1 to 13, characterized in that the volume content of fibers is constant at least 70% of the volume of the impregnated fiber material, particularly at least 80% of the volume of the impregnated fiber material, particularly at least 90% of the volume of the impregnated fiber material, and especially at least 95% of the volume of the impregnated fiber material.

15. The impregnated fiber material according to any one of claims 1 to 14, characterized in that the porosity level in the impregnated fiber material is less than 10%, particularly less than 5%, and particularly less than 2%.

16. The impregnated fiber material according to any one of claims 1 to 15, characterized in that the impregnated fiber material is a single layer.

17. The impregnated fiber material according to any one of claims 1 to 16, characterized in that the fiber material comprises carbon, glass, silicon carbide, basalt, silica fiber, natural fiber, particularly flax or hemp, lignin, bamboo, sisal, silk, or cellulose, particularly viscose fiber, or amorphous thermoplastic fiber having a glass transition temperature Tg that is higher than the Tg of the polymer or polymer mixture if it is amorphous, or higher than the Tm of the polymer or polymer mixture if it is semicrystalline, or semicrystalline thermoplastic fiber having a melting temperature Tm that is higher than the Tg of the polymer or polymer mixture if it is amorphous, or higher than the Tm of the polymer or polymer mixture if it is semicrystalline, or a mixture of two or more of the fibers, preferably a mixture of carbon, glass or silicon carbide fibers, and particularly continuous fibers selected from carbon fibers.

18. The impregnated fiber material according to any one of claims 1 to 17, characterized in that the thermoplastic polymer further comprises a carbonaceous filler, particularly carbon black or carbon nanofiller, preferably selected from graphene, carbon nanotubes, carbon nanofibrils or mixtures thereof.

19. The impregnated fiber material according to any one of claims 1 to 18, characterized in that the thermoplastic prepolymer further comprises a liquid crystal polymer or cyclic poly(butylene terephthalate), or a mixture containing the liquid crystal polymer or cyclic poly(butylene terephthalate) as an additive.

20. The impregnated fiber material according to any one of claims 1 to 19, characterized in that the impregnated fiber material is non-flexible.

21. A method for producing an impregnated fiber material according to any one of claims 1 to 20, comprising the steps of pre-impregnating or impregnating the fiber material with at least a thermoplastic polymer, wherein the thermoplastic polymer is an amorphous or semi-crystalline polymer having a glass transition temperature such as Tg ≥ 40°C, particularly Tg ≥ 100°C, particularly ≥ 120°C, the fiber content in the impregnated fiber material is 45 to 65 volume%, preferably 50 to 60 volume%, particularly 54 to 60 volume%, the number average molecular weight Mn of the thermoplastic polymer is 11,000 to 25,000 g / mol, and the melt viscosity of the thermoplastic polymer is 80 to 1500 Pa·s, measured by planar / planar rheology at 1 Hz and 2% deformation, at a temperature of Tg + 220°C.

22. A method for producing an impregnated fiber material according to claim 21, comprising the step of impregnating the fiber material with at least a thermoplastic polymer, wherein the number average molecular weight Mn of the thermoplastic polymer is 11,000 to 20,000 g / mol, preferably 12,000 to 18,000, the melt viscosity of the thermoplastic polymer is 80 to 650 Pa·s at a temperature of Tg + 220°C, preferably 100 to 450 Pa·s, and the thermoplastic polymer is a polyamide having Tg < 130°C.

23. The method according to claim 22, characterized in that the impregnation step is carried out particularly quickly through the melting path, particularly at a speed of at least 1 to 10 m / min, and particularly at at least 2 m / min, in the melting path.

24. The following steps: i) A step to obtain an impregnated fiber material, comprising impregnating a fiber material with at least one non-reactive thermoplastic polymer by a melting path, particularly by pultrusion molding of the molten polymer, by crosshead die extrusion, wherein the pre-impregnation step is performed using at least a thermoplastic polymer, the number average molecular weight Mn of the thermoplastic polymer is 11,000 to 20,000 g / mol, preferably 12,000 to 18,000, the melt viscosity of the thermoplastic polymer is 80 to 650 Pa·s at a temperature of Tg + 220°C, preferably 100 to 450 Pa·s, and the thermoplastic polymer is a polymer having Tg < 130°C, i) The method according to claim 22 or 23, characterized by comprising the step of optionally forming and calibrating the impregnated fiber material to obtain an impregnated fiber material consisting of a ribbon in the form of a thin band having a thickness of 0.2 to 5 mm, preferably 0.2 to 1.3 mm.

25. A method for producing an impregnated fiber material according to claim 21, comprising the step of pre-impregnating the fiber material, which takes the form of roving or several parallel rovings, with at least one non-reactive thermoplastic polymer, wherein the number average molecular weight Mn of the thermoplastic polymer is 14,000 to 25,000, preferably 15,000 to 21,000, the melt viscosity of the thermoplastic polymer is 150 to 1500 Pa·s, preferably 200 to 750 Pa·s at a temperature of Tg + 220°C, and the thermoplastic polymer is a polymer having Tg ≥ 130°C.

26. The method according to claim 25, characterized in that the pre-impregnation is carried out using a system selected from a fluidized bed, spraying with a spray gun, or by the continuous passage of fibers at particularly high speed in an aqueous dispersion of the non-reactive thermoplastic polymer powder, or an aqueous dispersion of the thermoplastic polymer particles, or an emulsion or aqueous suspension of the non-reactive thermoplastic polymer.

27. The method according to claim 25 or 26, characterized by including at least one heating step that does not use a support for the pre-impregnated fiber material.

28. The method according to claim 25 or 26, comprising at least one heating step performed by at least one support component (E) and at least one heating system, wherein the roving is in contact with part or all of the surface of the at least one support component (E) and the heating system scrolls over part or all of the surface of the at least one support component (E).

29. The method according to claim 27 or 28, characterized in that the heating system is selected from infrared lamps, UV lamps, convection heating, microwave heating, laser heating and high-frequency (HF) heating.

30. The following steps: i) A step to obtain a pre-impregnated fiber material, wherein the fiber material is pre-impregnated with at least one non-reactive thermoplastic polymer by spraying with a nozzle or spray gun through a fluid bed in a tank equipped with or not equipped with at least one support component (E') and through a drying path in a tank equipped with or not equipped with at least one support component (E'), wherein the pre-impregnation step is performed with at least one non-reactive thermoplastic polymer, the number average molecular weight Mn of the thermoplastic polymer is 14,000 to 25,000, preferably 15,000 to 21,000, the melt viscosity of the thermoplastic polymer is 150 to 1500 Pa·s at a temperature of Tg + 220°C, preferably 200 to 750 Pa·s, and the thermoplastic polymer is a polymer having Tg ≥ 130°C, step, ii) A step of heating the pre-impregnated fiber material without support to obtain the pre-impregnated fiber material, iii) A step of obtaining an impregnated fiber material by heating using at least one support component (E) and at least one heating system as described in claim 28 or 29, iv) Optionally, a step of forming and calibrating rovings or parallel rovings of the impregnated fiber material to obtain an impregnated fiber material consisting of ribbons in the form of thin bands. The method according to any one of claims 25 to 29, characterized by including the following:

31. The following steps: i) A step of pre-impregnating a fiber material with at least one non-reactive thermoplastic polymer, particularly by continuous passage of the fiber through a fluid bed of a dried polymer powder, an aqueous dispersion of polymer powder, or an emulsion or aqueous suspension of polymer, wherein the pre-impregnation step is performed by at least a thermoplastic polymer, the thermoplastic polymer is a polymer having Tg ≥ 130°C, the non-reactive thermoplastic polymer has a number average molecular weight Mn of 14,000 to 25,000, preferably 15,000 to 21,000, and the melt viscosity of the thermoplastic polymer is 150 to 1500 Pa·s, preferably 200 to 750 Pa·s, measured by planar / planar rheology at 1 Hz and 2% deformation, at a temperature of Tg + 220°C. ii) A step of heating the pre-impregnated fiber material without support to obtain the pre-impregnated fiber material, iii) Depending on the case, heating using at least one support component (E) and at least one heating system to obtain an impregnated fiber material, iv) Optionally, a step of forming and calibrating rovings or parallel rovings of the impregnated fiber material to obtain an impregnated fiber material consisting of ribbons in the form of thin bands. The method according to any one of claims 25 to 29, characterized by including the following:

32. The method according to any one of claims 21 to 31, characterized in that one or more supports (E'') are located upstream of the system.

33. The method according to any one of claims 25 to 32, characterized in that the dry powder route is carried out at a speed of 5 to 30 m / min and the aqueous dispersion route is carried out at a speed of at least 15 m / min.

34. Use of the impregnated fiber material according to any one of claims 1 to 20, by automated laying of the ribbon using a robot for the manufacture of a ribbon suitable for the manufacture of three-dimensional composite parts.

35. Use of an impregnated fiber material according to any one of claims 1 to 20 for the manufacture of a thermoformable sheet.

36. The use according to claim 35, characterized in that the impregnated fibrous material is pre-cut into fragments, and the fragments are randomly associated or oriented for the manufacture of a thermoformable sheet.

37. Use of at least one nonreactive thermoplastic polymer, wherein the at least one nonreactive thermoplastic polymer is amorphous or semi-crystalline thermoplastic polymer having a glass transition temperature such as Tg ≥ 40°C, particularly Tg ≥ 100°C, particularly ≥ 120°C, for impregnation into a fibrous material, the fiber content in the impregnated fibrous material is 45 to 65 vol%, preferably 50 to 60 vol%, particularly 54 to 60 vol%, the number average molecular weight Mn of the thermoplastic polymer is 11,000 to 25,000 g / mol, and the melt viscosity of the thermoplastic polymer is 80 to 1500 Pa·s when measured by planar / planar rheology at a temperature of Tg + 220°C, 1 Hz and 2% deformation, as defined in any one of claims 1 to 11 and 18 to 19.

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