Method for preparing impregnated fibrous materials by reactive pultrusion - Patent Application 20070122999

Abstract

The present invention relates to a method for producing at least one impregnated fibrous material comprising a fibrous material made of continuous fibers and at least one thermoplastic polymer having a glass transition temperature Tg of 40° C. or higher or a melting temperature Tm of 400° C. or lower, the method comprising the step of impregnating the at least one fibrous material in the presence of the fibrous material in a pultrusion head by injecting a reactive composition in a molten state, comprising at least one precursor of the thermoplastic polymer, the reactive composition comprising at least one precursor of the thermoplastic polymer, so that the at least one fibrous material separates in its thickness as it enters the pultrusion head, in particular into n layers of substantially equal thickness. wherein n is between 2 and 20, each layer circulates in its own channel within the pultrusion head, and as the layers recombine at the outlet from each channel, the reactive composition is injected into each channel and / or between the layers, the channels being heated at a temperature such that the initial melt viscosity of the reactive composition is less than 50 Pa s, and impregnation begins at the moment of injection and ends before or after the layers recombine by overlapping to form the at least one final impregnated fibrous material in which the precursor of the thermoplastic polymer is at least partially polymerized.

Description

[Technical Field]

[0001] The present invention relates to a method for preparing a fibrous material impregnated with a thermoplastic polymer by reactive pultrusion, to the ribbons obtained by said method, and to their uses. [Background technology]

[0002] In conventional thermoplastic pultrusion, the impregnating resin is a polymer that is nearly non-reactive and has a low enough viscosity (<100 Pa.s) that it can be impregnated into the fiber strand (roving) at line speeds of 0.2-1 m / min while maintaining reasonable head lengths, limiting the friction surface of the roving and processing costs.

[0003] The impregnation of the roving can be characterized by the diffusion time of the resin to the core of the roving, which depends on several factors, such as the viscosity of the thermoplastic polymer, the line speed, and the thickness of the roving.

[0004] In the impregnation technique, the use of a support is known to shorten the diffusion time of the resin through the roving and to homogenize the fiber distribution, from rovings with a circular cross section to rovings with a rectangular cross section with a very high width / thickness ratio (large width, small thickness).

[0005] This is done by applying tension to the roving, causing it to alternately circulate above and below a series of contact surfaces. Supports may be upstream of the die and / or inside the die. The upstream supports serve to spread the roving, while the internal supports allow for the creation of a roving / solid contact area.

[0006] Thus, International Application WO2013086258 describes the impregnation of a fibrous material with a non-reactive thermoplastic polymer by passing strands or rovings through an impregnation area in a pultrusion head in channels, in which a thermoplastic polymer is injected at the entrance of the channels onto one of the surfaces of said strands, i.e. obtaining an asymmetrically impregnated fibrous material, in the thickness direction, in a fiber-rich portion and in a thermoplastic polymer-rich portion.

[0007] Each channel present in the pultrusion head comprises several contact surfaces that allow friction of the strands so as to reduce the diffusion time of the thermoplastic polymer through the roving.

[0008] The maximum tensile force that the strands can withstand is 1000 to 15,000 MPa for strands with a mass per unit length of 0.05 to 2 g / m. The melt viscosity of the thermoplastic polymers used is 25 to 50,000 Pa.s. Those skilled in the art will understand that such high viscosities do not allow impregnation in a sufficiently fast time and / or over a sufficiently large thickness to be of any interest from an industrial point of view.

[0009] When considering a roving passing through the impregnation head of a channel, this roving is, at any point in its journey, contained in the volume of the channel, which is made up of the volume of the roving and the free volume. Without this free volume, the fibers would occupy the entire volume of the channel, resulting in very significant friction at the walls and premature breakage of the roving. It is therefore this free volume, necessary for the process, that creates a residence time of the resin in the head, which must be limited as much as possible while still allowing the diffusion of the thermoplastic polymer in the roving, and at the same time not leading to too high a viscosification of the resin before impregnation, which would hinder impregnation or block the pultrusion head.

[0010] Furthermore, if a mixture of prepolymers is used for the polymerization, these prepolymers must be sufficiently fluid to allow the fibers to be impregnated with the reactive mixture. Therefore, particularly when the Tg of the prepolymer is high, high temperatures are required to effect the impregnation, which would otherwise cause the polymerization reaction to proceed too quickly and would cause viscosity to prevent accurate impregnation of the fibers. Summary of the Invention

[0011] The present invention relates to a method for producing at least one impregnated fibrous material comprising a fibrous material made of continuous fibers and at least one thermoplastic polymer having a glass transition temperature Tg of 40°C or higher, in particular 80°C or higher, preferably 100-200°C, more preferentially 110-200°C, or a melting point Tm of 400°C or lower, in particular 350°C or lower, in particular 290°C or lower, the method comprising the step of impregnating the at least one fibrous material by injecting a molten reactive composition comprising at least one precursor of the thermoplastic polymer in the presence of the fibrous material at a pultrusion head; the at least one fibrous material is separated in its thickness into n layers as it enters the pultrusion head, particularly into n layers of substantially equal thickness, n being between 2 and 20, particularly between 2 and 10, more particularly between 2 and 5, and especially equal to 4; each layer circulating in a channel specific to it in the pultrusion head; injecting the reactive composition into each channel and / or between the layers as the layers recombine at the outlet from each channel; the channel is heated to a temperature such that the reactive composition has an initial melt viscosity of less than 50 Pa.s, more preferentially less than 20 Pa.s, even more preferentially less than 10 Pa.s, in particular less than 5 Pa.s, and the impregnation begins at the moment of injection and ends before or after the layers are recombined by superposition to form the at least one final impregnated fibrous material in which the precursor of the thermoplastic polymer is at least partially polymerized. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 shows a pultrusion head of Example 1 equipped with a crosshead die equipped with a system for separating fibers into layers using a support system submerged in a bath of molten resin: a system suitable for use with non-reactive resins. The fibrous material is separated into four, although in a single impregnation chamber. Therefore, the separated fibrous material does not circulate in its own channels. [Figure 2] FIG. 2 shows a cross-sectional view of the morphology of the impregnated fibrous material (pultrusion profile) of Example 1 using the pultrusion head described in FIG. 1 with non-reactive resin 11 / 10T / 10T. [Figure 3] FIG. 1 shows a pultrusion head of Example 3 including an in-line die that does not include dead space and does not include a system for separating the fibers into different layers (based on S. Lecorre, LTN, Nantes, International Journal of Microstructure and Materials Properties, January 2012). [Figure 4] FIG. 4 shows the morphology of an impregnated fibrous material (pultrusion profile) using a reactive composition of the 11 / 10T / 10T type with the pultrusion head described in FIG. 3. [Figure 5] FIG. 1 shows a pultrusion head according to Example 4 of the present invention, which does not include dead spaces and includes a system for separating the fibrous material into various layers, thus circulating it in its own channels. [Figure 6] FIG. 6 shows the morphology of a pultrusion profile (Example 4) made with a pultrusion head as shown in FIG. 5 using a reactive composition of the 11 / 6T / 10T type. [Figure 7] FIG. 6 shows the morphology of a profile (Example 5) made with a reactive composition of the BACT / 10T type with the pultrusion head described in FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0013] The inventors have unexpectedly found that it is possible to separate the thickness of the fibrous material to be impregnated with the reactive composition into several layers, in particular several layers of substantially equal thickness, comprising a precursor (also called reactive oligomer or reactive prepolymer) with a low initial melt viscosity (<50 Pa.s), the reactive composition to be impregnated into said layers, by circulating each layer in a channel heated to a temperature that makes it possible to minimize the diffusion time of the reactive composition in said layers and thus to impregnate said layers before or after recombination, while at least partially carrying out polymerization.

[0014] In other words, the method according to the invention makes it possible to satisfy the double constraint of raising the initial viscosity sufficiently to prevent a sufficiently high molar mass (Mn) of the polymer so as to provide good mechanical strength, and "controlling" this increase in viscosity / mass so as to ensure impregnation before the viscosity becomes too high.

[0015] This method also allows for minimizing the dead space in each channel.

[0016] This method therefore makes it possible to achieve line speeds of more than 1 m / min and therefore significantly reduce the production costs of pultruded profiles.

[0017] Furthermore, the reactivity of the oligomers makes it possible to achieve, after complete polymerization, even better mechanical properties than those obtained in conventional pultrusion with comparable impregnation quality.

[0018] The glass transition temperature Tg and the melting temperature Tm are measured by DSC according to the standard ISO11357-2:2013 and the standard ISO11357-3:2013.

[0019] The melt viscosity is measured by oscillatory rheology in a Physica MCR301 apparatus between two parallel flat plates, 25 mm in diameter, at 10 rad / s under nitrogen flushing and 5% deformation, at a temperature of Tm≦T≦Tm+50°C for semi-crystalline polymers or Tg+220°C for amorphous polymers.

[0020] Semicrystalline polymers within the meaning of the present invention refer to polymers having a melting point (Tm) in DSC according to ISO standard 11357-3:2013 and a crystallization enthalpy during a cooling process at a rate of 20 K / min, measured in DSC according to ISO standard 11357-3 of 2013, of 30 J / g or more, preferably 35 J / g or more.

[0021] Amorphous polymers within the meaning of the present invention refer to polymers that have only a glass transition temperature (and not a melting point (Tm)) according to DSC in accordance with ISO standard 11357-2:2013, or polyamides with very low crystallinity that have a glass transition temperature according to DSC in accordance with ISO standard 11357-2:2013 and a melting point such that the crystallization enthalpy during a cooling process at a rate of 20 K / min is less than 30 J / g, in particular less than 20 J / g, preferably less than 15 J / g, in differential scanning calorimetry (DSC) measured in accordance with ISO standard 11357-3:2013.

[0022] The expression "substantially equal thickness" means that after separation of the fibrous material (or strands), each layer has a thickness of e±25%, in particular a thickness of e±12%.

[0023] Each layer circulates in its own channel; therefore, there is only one layer per channel and there can be no more than two layers per channel.

[0024] Regarding reactive compositions: The expression "reactive composition" means that the molecular weight of said reactive composition (or its melt viscosity) will change during its implementation due to the reaction of reactive prepolymers (or oligomers) with themselves or with each other by condensation or with chain extenders by polyaddition, resulting in the final polyamide polymer of the thermoplastic matrix after polymerization or by complete nucleophilic substitution, without removal of volatile by-products.

[0025] In the case of the reactive compositions of the present invention, the reactive prepolymers are prepared by a standard polycondensation reaction between the corresponding diamine and a diacid component, optionally an amino acid or a lactam. Prepolymers carrying amine and carboxyl functional groups X and Y in the same molecular chain can be obtained, for example, by adding a combination of monomers (amino acids, diamines, diacids) with the same total amount of amine and carboxyl motifs. Another way to obtain these prepolymers carrying one functional group X and one functional group Y is, for example, by combining a prepolymer carrying two identical functional groups X = amine with a diacid prepolymer carrying Y = carboxy, with an overall molar concentration of acid functional groups equal to the molar concentration of the initial amine functional group X.

[0026] To obtain prepolymers functionalized with the same functional group (amine or carboxy) on the same molecular chain, an excess of diamine (or, in general, amine functional groups) is sufficient to have terminal amine functional groups, or an excess of diacid (or, in general, carboxy functional groups) is sufficient to have terminal carboxy functional groups.

[0027] According to a first possibility, the at least partially polymerized reactive thermoplastic prepolymer comprises, in the same molecular chain (i.e. in the same prepolymer), at least one reactive (especially polyamide) prepolymer carrier, two terminal functional groups X' and Y', which are respectively co-reactive with each other by condensation, X' and Y' being amine and carboxy, or carboxy and amine, respectively.

[0028] Advantageously, said at least partially polymerized reactive thermoplastic prepolymer is composed of at least one reactive prepolymer (in particular a polyamide), two terminal functional groups X' and Y', respectively, functional groups that are co-reactive by condensation, held together in the same molecular chain (i.e. in the same prepolymer), X' and Y' being amine and carboxyl, or carboxyl and amine, respectively.

[0029] Therefore, there is no chain extender present in this first embodiment.

[0030] According to a second possibility, said at least partially polymerized reactive thermoplastic prepolymer comprises at least two polyamide prepolymers reacted together and each carrying two identical terminal functional groups X' or Y' (identical for the same prepolymer and different between the two prepolymers), with the proviso that said functional group X' of a prepolymer can only react with said functional group Y' of the other prepolymer, in particular by condensation, and more particularly X' and Y' are amine and carboxyl, or carboxyl and amine, respectively.

[0031] Advantageously, said at least partially polymerized reactive thermoplastic prepolymer is composed of at least two polyamide prepolymers that have reacted together and each carry two identical terminal functional groups X' or Y' (identical for the same prepolymer and different between the two prepolymers), with the proviso that said functional group X' of a prepolymer can only react, in particular by condensation, with said functional group Y' of the other prepolymer, and more particularly X' and Y' are amine and carboxyl, or carboxyl and amine, respectively.

[0032] The at least two prepolymers may or may not be premixed together.

[0033] This condensation (or polycondensation) reaction can lead to the appearance of by-products.

[0034] Therefore, there is no chain extender present in this second embodiment.

[0035] The reaction of the two prepolymers may be total or partial.

[0036] According to a third possibility, the at least partially reactive thermoplastic prepolymer polymerized with a chain extender is: a1) At least one reactive thermoplastic prepolymer as already defined above, with the proviso that this prepolymer carries n identical reactive end functional groups X selected from: -NH2 (amine), -CO2H (carboxy) and -OH (hydroxyl), the n identical reactive end functional groups X being preferably -NH2 (amine) and -CO2H (carboxy), and n being 1 to 3, preferably 1 to 2, more preferably 1 or 2, and more particularly 2. a2) at least one chain extender Y-A'-Y, where A' is a hydrocarbon bisubstituent, carrying two identical terminal reactive functional groups Y which are reactive with at least one functional group X of the prepolymer a1) by polyaddition (without elimination of reaction by-products), and preferably having a molecular mass of less than 500, more preferably less than 400; Includes.

[0037] Advantageously, said at least one reactive thermoplastic prepolymer partially polymerized with a chain extender is composed of a1) and a2) as defined above.

[0038] Advantageously, Y is selected from: oxazine, oxazoline, oxazolinone, oxazinone, imidazoline, epoxy, isocyanate, maleimide, cyclic anhydride, in particular oxazine, oxazoline, oxazolinone, oxazinone, imidazoline, maleimide, cyclic anhydride, preferably X1 is CO2H and Y1 is selected from epoxy and oxazoline.

[0039] NH2(amine) refers to primary and secondary amines.

[0040] Depending on the X functionality carried by the semicrystalline polyamide prepolymer a1), examples of suitable extenders a2) include: When -X is NH2 or OH, preferably NH2: Any chain extender Y-A'-Y corresponds to: Y is selected from the group: maleimides, isocyanates, optionally blocked oxazinones and oxazolinones, cyclic anhydrides, preferably oxazinones and oxazolinones, in particular maleimides, oxazinones and oxazolinones, cyclic anhydrides, preferably oxazinones and oxazolinones, and A' is a Y group selected from a carbonaceous substituent carrying a spacer or reactive functional group, or, in the case of Y = oxazinone and oxazolinone, a covalent bond between two functional groups (groups) Y; or an aliphatic hydrocarbon chain or an aromatic and / or alicyclic hydrocarbon chain, the latter two of which contain at least one ring having 5 or 6 carbon atoms, optionally substituted, and optionally said aliphatic hydrocarbon chain having a molecular weight of 14 to 200 g.mol-1; or, The chain extender Y-A'-Y corresponds to Y being a caprolactam group and A' being a carbonyl substituent, e.g., carbonyl biscaprolactam, or A' being terephthaloyl or isophthaloyl; Alternatively, the chain extender Y-A'-Y carries a cyclic anhydride group Y, preferably the extender is selected from carboxylic alicyclic and / or aromatic dianhydrides, more preferably: ethylene tetracarboxylic dianhydride, pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, perylene tetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 1,2,3,4-cyclopentadiene ... tetracarboxylic dianhydride, hexafluoroisopropylidenebisphthalic dianhydride, 9,9-bis(trifluoromethyl)xanthenetetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 3,3',4,4'-diphenylethertetracarboxylic dianhydride, or mixtures thereof; and -When X is COOH: The chain extender Y-A'-Y is: Y selected from the group: oxazoline, oxazine, imidazoline, or aziridine, such as 1,1'-iso-phthaloyl-bis(2-methylaziridine) or 1,1'-tere-phthaloyl-bis(2-methylaziridine), or epoxy A' is a carbon spacer or substituent, as defined above. Corresponds to.

[0041] More specifically, in the chain extender Y-A'-Y, when the functional group Y is selected from oxazinone, oxazolinone, oxazine, oxazoline, or imidazoline, particularly oxazoline, in this case, in the chain extender represented by Y-A'-Y, A' can represent alkylene, such as -(CH)-, where m is in the range of 1 to 14, preferably 2 to 10, or A' can represent cycloalkylene and / or substituted (alkyl) or unsubstituted arylene, such as benzenearylene, for example, o-phenylene, m-phenylene, p-phenylene, or naphthalenearylene, and preferably A' is arylene and / or cycloalkylene.

[0042] In the case of carbonyl-biscaprolactam or terephthaloyl-biscaprolactam or isophthaloyl-biscaprolactam as chain extender Y-A'-Y, preferred conditions avoid the removal of by-products such as caprolactam during the polymerization and during the melt run.

[0043] When Y is epoxy, the chain extender may be bisphenol A diglycidyl ether (BADGE) and its hydrogenated derivatives (alicyclic), bisphenol F diglycidyl ether, tetrabromobisphenol A diglycidyl ether, or hydroquinone diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, butylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, polyethylene glycol diglycidyl ethers with Mn<500, Mn<500 polypropylene glycol diglycidyl ether having Mn<500, polytetramethylene glycol diglycidyl ether having Mn<500, resorcinol diglycidyl ether, neopentyl glycol diglycidyl ether, bisphenol A polyethylene glycol diglycidyl ether having Mn<500, bisphenol A polypropylene glycol diglycidyl ether having Mn<500, dicarboxylic acid diglycidyl esters such as terephthalic acid glycidyl ester, or epoxidized diolefins (dienes), or doubly epoxidized ethylenically unsaturated fatty acids, diglycidyl 1,2 cyclohexanedicarboxylate, and mixtures thereof.

[0044] In the case of carbonyl biscaprolactam or terephthaloyl biscaprolactam or isophthaloyl biscaprolactam as chain extender Y-A'-Y, preferred conditions avoid the removal of by-products such as caprolactam during the polymerization and during the melt run.

[0045] In the final case above, where Y represents a blocked isocyanate functional group, this blocking can be achieved by means of blocking agents for isocyanate functional groups, such as epsilon-caprolactam, methyl ethyl ketoxime, dimethylpyrazole, diethyl malonate.

[0046] Similarly, when the extender is a dianhydride that reacts with the prepolymer P(X')n where X = NH2, preferred conditions avoid imide ring formation during polymerization and melt runs.

[0047] For X=OH or NH2, the Y group is preferably selected from isocyanates (unblocked), oxazinones and oxazolinones, more preferentially oxazinones and oxazolinones, and A' is as defined above as a spacer or hydrocarbon substituent.

[0048] Examples of chain extenders carrying a reactive functional group Y of oxazoline or oxazine suitable for carrying out the present invention include those referred to under "A," "B," "C," and "D" on page 7 of application EP 0 581 642, and the methods of preparation and reaction modes described therein, in which "A" is a bisoxazoline, "B" is a bisoxazine, "C" is a 1,3-phenylenebisoxazoline, and "D" is a 1,4-phenylenebisoxazoline.

[0049] By way of example, when X=COH, the chain extender Y-A′-Y is 1,4-phenylenebisoxazoline, and the resulting reaction product has at least one repeat motif having the following structure: -OC(O)-PC(O)-O-R1-NH-C(O)-A'-C(O)-NH-R1- [In formula: P is a polyamide having acid ends HO-C(O)-PC(O)-OH derived from the amide motif (A), the amide motif (B), or the amide motif (C), R1(CH2)2, and A' is phenyl]

[0050] Examples of chain extenders having an imidazoline-reactive functional group Y that are suitable for the practice of the present invention include those listed and may be referenced as ("A" to "F") in Table 1 on pages 7-8 and 10 of Application EP 0 739 924, as well as the methods of preparation and reaction modes thereof described therein.

[0051] Examples of chain extenders having a reactive functional group Y=oxazinone or oxazolinone suitable for carrying out the present invention include those described and may be referred to as references "A" to "D" on pages 7-8 of application EP 0 581 641, as well as the methods of preparation and reaction modes thereof described therein.

[0052] Examples of suitable oxazinone (6-membered ring) and oxazolinone (5-membered ring) Y groups include benzoxazinone, oxazinone, or oxazolinone Y group derivatives, where A' can be a single covalent bond to the corresponding respective extender, which are bis-(benzoxazinone), bisoxazinone, and bisoxazolinone.

[0053] A' may also be a C1-C14 alkylene, preferably a C2-C10 alkylene, but preferably A' is an arylene, more particularly a phenylene (substituted with Y in the 1,2 or 1,3 or 1,4 positions) or a naphthalene substituent (disubstituted with Y) or a phthaloyl (isophthaloyl or terephthaloyl), or A' may be a cycloalkylene.

[0054] For Y functional groups such as oxazine (6-membered ring), oxazoline (5-membered ring), and imidazoline (5-membered ring), the substituent A' may be as described above, where A' can be a single covalent bond, and the corresponding respective extenders are: bisoxazine, bisoxazoline, and bisimidazoline. A' may also be a C1-C14 alkylene, preferably a C2-C10 alkylene. The substituent A' is preferably an arylene, more particularly a phenylene (substituted with Y at the 1,2-position, or the 1,3-position, or the 1,4-position), or a naphthalene substituent (disubstituted with Y), or a phthaloyl (isophthaloyl or terephthaloyl), or A' may be a cycloalkylene.

[0055] When Y=aziridine (a nitrogen heterocycle having three atoms corresponding to ethylene oxide replacing the ether -O— with —NH—), the substituent A′ can be phthaloyl (1,1′-isophthaloyl or 1,1′-terephthaloyl), with 1,1′-isophthaloyl-bis(2-methylaziridine) being an example of this type of extender.

[0056] The presence of a catalyst for the reaction of the prepolymer P(X)n with the extender Y-A'-Y, in a concentration ranging from 0.001 to 2%, preferably from 0.01 to 0.5%, relative to the total weight of the two co-reactants listed, can promote the (poly)addition reaction and thus shorten the production cycle. Such catalysts can be selected from 4,4'dimethylaminopyridine, p-toluenesulfonic acid, phosphoric acid, NaOH, and optionally those described for polycondensation or transesterification in EP 0 425 341, page 9, lines 1-7.

[0057] Depending on the specific case of the selection of the extender, A' can represent alkylene, such as -(CH)-, where m is in the range of 1 to 14, preferably in the range of 2 to 10, or alkyl-substituted or unsubstituted arylene, such as benzenearylene (o-phenylene, m-phenylene, p-phenylene, etc.) or naphthalene (including arylene: naphthalenylene). Preferably, A' represents arylene, which can be substituted or unsubstituted benzene or naphthalene.

[0058] As already explained, said chain extender (a2) preferably has a molecular weight of less than 500, more preferentially less than 400.

[0059] The proportion of extender used varies from 1% to 20% by weight, in particular from 5% to 20% by weight, especially from 10% to 20% by weight.

[0060] In the case of the reactive compositions of the present invention according to definition a), the reactive prepolymers are prepared by a standard polycondensation reaction between the corresponding diamine and diacid components, optionally amino acids or lactams. Prepolymers carrying amine and carboxyl functions X' and Y' in the same molecular chain can be obtained by adding a combination of monomers (amino acids, diamines, diacids) with the same total amount of amine and carboxyl motifs. Another way to obtain these prepolymers carrying one X' and one Y' functional group is, for example, by combining a prepolymer carrying two identical X' = amine functional groups with a diacid prepolymer carrying Y' = carboxy, with an overall molar concentration of acid functional groups equal to the molar concentration of the initial X' amine functional group.

[0061] To obtain prepolymers functionalized with the same functional group (amine or carboxy) on the same molecular chain, it is sufficient to have an excess of diamine (or, in general, amine functional groups) to have terminal amine functional groups, or an excess of diacid (or, in general, carboxy functional groups) to have terminal carboxy functional groups.

[0062] In the case of a prepolymer P(X1)n having n identical X1 functional groups, functionality 1 can be obtained in the presence of a monofunctional blocking component (monoacid or monoamine, depending on the nature of X1=amine or carboxy).

[0063] The functionality n=2 is obtained from difunctional components: a diamine and a diacid, one in excess, and can be bonded to X1 according to this excess.

[0064] For example, for n=3, the prepolymer P(X1)n requires the presence of a trifunctional component, e.g., a triamine (1 mole per prepolymer chain) along with a diamine in reaction with a diacid. The preferred functionality for P(X1)n is n=2.

[0065] Optionally, the thermoplastic prepolymer or thermoplastic prepolymer mixture further comprises a carbon-based filler, in particular carbon black or a carbon nanofiller, preferably selected from among carbon nanofillers, in particular graphene and / or carbon nanotubes and / or carbon nanofibrils, or mixtures thereof, which serve to conduct electricity and heat and, as a result, to make the prepolymer matrix more easily meltable when heated.

[0066] In particular, the number average molecular weight Mn of the final thermoplastic polymer after complete polymerization, calculated from the concentration of terminal functional groups measured by potentiometric titration in solution and determined by the functionality of the prepolymer, is preferably in the range of 10,000 to 40,000, preferably in the range of 12,000 to 30,000. The mass Mn can also be measured by size exclusion chromatography or by NMR.

[0067] These Mn values ​​can correspond to an intrinsic viscosity of 0.8 or more measured in m-cresol according to standard ISO 307:2007, but by changing the solvent (using m-cresol instead of sulfuric acid and at a temperature of 20°C).

[0068] The precursor prepolymer has a number average molecular weight Mn in the range of 500 to 10,000, preferably 1,000 to 6,000, and particularly 2,500 to 6,000.

[0069] In one embodiment, the reactive composition comprises: - 50 to 100% by weight of at least one precursor of said thermoplastic polymer, - 0 to 50% by weight of at least one additive and / or at least one other thermoplastic polymer Containing or consisting of.

[0070] The additives can be selected from, but are not limited to, special additives capable of absorbing at the wavelength of a laser, for example, a UV or IR laser, thereby enabling the use of automated fiber placement (AFP) techniques when the latter employ laser heating methods, and integrating the composite ribbons with one another, especially in the case of composite ribbons with a glass or carbon fiber base. Other additives, such as thermal stabilizers, can be added to the precursor composition and therefore present in the final thermoplastic composite used in the final application; in particular, these stabilizers are antioxidants against thermal and / or photo-oxidation of the thermoplastic matrix polymer. Such antioxidants are of the sterically hindered phenol type and / or sterically hindered amine type (commonly known by the name HALS). Suitable examples of such additives include carbon black (CB) in the form of a CB powder, or preferably in the form of a masterbatch having a base of CB and polyethylene (PE), or a base of CB and polyamide (PA), TiO (titanium oxide), ZnO (zinc oxide), and, in the case of IR lasers, indium tin oxide (sold by Evonik), as well as the heat stabilizers listed above. An example of a CB+PE masterbatch containing about 40% CB is EUTHYLEN® sold by BASF. An example of a CB+PA masterbatch containing about 15% CB is RENOL® BLACK sold by CLARIANCE.

[0071] The additive may also be a filler, which, in addition to long reinforcing fibers, may in particular be any filler known to those skilled in the art of composites. This may in particular be a thermally and / or electrically conductive filler, such as metal powder, powdered carbon black, carbon fibrils, carbon nanotubes (CNTs), silicon carbide, boron carbonitride, boron nitride, or silicon nitride. On this subject, reference may be made to the applicant's application WO 2010 / 130930.

[0072] Obviously, long reinforcing fibers (or long fiber reinforcement) are excluded from the additive.

[0073] The additive may also be a flame retardant, such as, for example, a metal salt selected from metal phosphinates, metal salts of diphosphinic acids, polymers containing at least one metal salt of phosphinic acids, polymers containing at least one metal salt of diphosphinic acids, etc.

[0074] The expression "other polymer" refers to any non-reactive thermoplastic polymer, and in particular to polyamide polymers, especially aliphatic, cycloaliphatic, or aromatic polyamides, which may be semi-crystalline or amorphous.

[0075] "Non-reactive thermoplastic polymer" should be understood to mean a polymer whose molecular weight is no longer likely to change significantly, i.e., whose number average molecular weight (Mn) changes by less than 50% during its run.

[0076] Regarding injections As the reactive composition leaves each channel, it is injected into each channel at the inlet of each channel, at the outlet of each channel, or between the inlet and outlet of each channel (in the latter case, there may be one or more injection points), and / or at a location which may be between the layers.

[0077] In a first variant, injection takes place between the layers as the reactive composition leaves each channel.

[0078] Advantageously, in this embodiment, the reactive composition is injected between the pair of layers at the outlet of the channel and then impregnates the two layers to form an impregnated bilayer material, which is then assembled with the others in its thickness to form the final impregnated fibrous material.

[0079] In a second variant, the injection is carried out at the entrance of each channel.

[0080] In a third variant, injection is carried out at the entrance of each channel and between the layers as the reactive composition leaves each channel.

[0081] In a fourth variant, injection is performed at the inlet of each channel and between the inlet and outlet of each channel.

[0082] In a fifth variant, injection is carried out between the inlet and outlet of each channel and between the layers as the reactive composition leaves each channel.

[0083] In a sixth variant, injection is carried out at the inlet of each channel, and between the inlet and outlet of each channel, and between the layers, as the reactive composition leaves each channel.

[0084] Regarding channels and layers The fibrous material is composed of a set of rovings, possibly up to several thousand.

[0085] Prior to impregnation, the fibrous material separates into n layers in its thickness as it enters the pultrusion head. It is clear that when at least one fibrous material enters the pultrusion head, and consequently several fibrous materials enter the pultrusion head, each fibrous material separates into n layers in its thickness.

[0086] The components of the reactive composition are mixed in the feed channel, at the inlet or outlet of said channel.

[0087] The channel is heated to a temperature such that the reactive composition has an initial melt viscosity of less than 50 Pa.s, more preferentially less than 20 Pa.s, even more preferentially less than 10 Pa.s, especially less than 5 Pa.s.

[0088] Initial viscosity means the viscosity of the reactive composition at time t of mixing in the feed channel, i.e. when the reactive composition is introduced into the feed channel, the initial viscosity of the reactive composition is less than 50 Pa.s, more preferentially less than 20 Pa.s, even more preferentially less than 10 Pa.s, in particular less than 5 Pa.s, or when the reactive composition is introduced between the layers at the outlet of the channel, each layer circulating in a heated channel, the layers being themselves at the temperature of the channel, the initial viscosity of the reactive composition is also less than 50 Pa.s, more preferentially less than 20 Pa.s, even more preferentially less than 10 Pa.s, in particular less than 5 Pa.s.

[0089] During injection of the reactive composition, a low viscosity allows for rapid impregnation of the layer with the reactive composition.

[0090] Impregnation begins at the moment of injection, and polymerization of the reactive composition begins at the time of mixing the components or just before impregnation begins.

[0091] Therefore, in the process according to the invention, impregnation and at least partial polymerization occur simultaneously.

[0092] Depending on the location of the injection, the impregnation is completed either before collecting the layers if the injection is performed at the inlet of each channel and / or between the inlet and outlet of each channel, or after collecting the layers if the injection is performed between the inlet and outlet of each channel and / or at the outlet of each channel.

[0093] The gathering is of course carried out by superposing the impregnated layers together to obtain the impregnated fibrous material.

[0094] Depending on the location of injection, impregnation and at least partial polymerization occur simultaneously in the method according to the invention, and therefore the precursor impregnating the fibrous material is at least partially polymerized after the layer is assembled.

[0095] The expression "at least partially polymerized" means that the number average molecular weight has increased by at least equal to two times, but not to more than 10,000, preferably 8,000.

[0096] After collection, the fibrous material impregnated with the at least partially polymerized precursor is still located in a single channel pultrusion head with its own heating system and optional support, which allows impregnation to be terminated and / or polymerization of the reactive mixture to continue, as desired.

[0097] In one embodiment, the method defined above is characterized in that the maximum thickness e of each layer is such that the impregnation time of each layer is less than or equal to the time required to increase the Mn of the reactive composition in said layer by a factor of 5, preferentially by a factor of 3 and especially by a factor of 2.

[0098] In other words, the method defined above is such that the maximum thickness e of each n layer is the product of the permeability K and the fluid pressure applied to said layer P, the volume fraction α of the composition in the fibrous medium. f and the viscosity μ of the reactive composition. sf , characterized in that it is subject to a maximum limit determined as being proportional to the square root of the integral over , said proportionality constant C being less than or equal to 14, in particular less than or equal to 7, and more particularly less than or equal to 3, i.e.: TIFF0007745533000001.tif15170

[0099] Additionally, a channel is defined as representing the volume through which the layer of fibrous material travels as it passes through the impregnation head.

[0100] If a fibrous material is considered to be randomly selected in one of the layers passing through the impregnation head of the channel, this roving will at any point in its journey be included in the volume of the channel consisting of the volume of said roving, creating a layer and a free volume, which would otherwise occupy the entire volume of the channel, resulting in very significant friction at the walls and premature breakage of the roving.

[0101] It is therefore this free volume, necessary for the process, that results in a residence time for the reactive composition in the head that is different from the residence time of the roving (directly related to the line speed).

[0102] In one embodiment, the average residence time of the reactive composition in the head is at most equal to 3 times, preferably 2 times, even more preferably 1.5 times the residence time of said fibrous material.

[0103] This makes it possible to avoid clogging of the head due to local excessive viscosity which would inhibit the movement of the layer and prevent its proper impregnation.

[0104] The channels can have a variety of shapes, but in one embodiment are cylindrical or non-cylindrical, particularly cylindrical.

[0105] A cylinder is a ruled surface whose generators are parallel, i.e., its surface is made up of parallel lines in space.

[0106] Thus, the ruled surface can be square, rectangular, circular, elliptical (or oval), conical, U-shaped, or T-shaped.

[0107] The thickness of the channel is the characteristic dimension of the base of the cylinder, so that if the base is square, e = the side of the square. If the base is rectangular, the characteristic dimension is the smaller side corresponding to the thickness. If the base is circular, e = the diameter.

[0108] If the base is elliptical, e = minor axis of the ellipse.

[0109] In one embodiment, the channels are cylindrical in shape and each channel has a thickness proportional to the thickness of each of the n layers, with the thickness of each channel being between 2 and 3 times the thickness of each of the n layers, and particularly between 1.5 and 2 times the thickness of each layer.

[0110] Advantageously, the channel is cylindrical with a rectangular surface.

[0111] Friction points or contact areas (or contact points) can be alternately located above or below the fibrous material in each channel, thus allowing for increased local pressure, thereby allowing for spreading of the layer of fibrous material and / or reducing impregnation times.

[0112] These contact points make it possible to create a skate effect in the support / roving junction area, thereby shortening the diffusion time.

[0113] However, the number and surface area of ​​contact areas must be limited and must have a sufficiently large radius of curvature so as not to result in breakage of the fibrous material (roving) due to excessive tension on the fibers.

[0114] In one embodiment, each channel has at least one contact area having a radius of curvature greater than d / break eps (d / ε), where d is the diameter of the fibers of the fibrous material and eps is the breaking strain of the fibers, and the at least one contact area is alternately positioned above or below the fibrous material (roving) during its movement in the impregnation head to cause and / or maintain the spreading of the fibrous material, possibly initiated in advance upstream of the head, without damaging said fibrous material.

[0115] The strain at break of the fiber is determined on a cylinder of carbon / epoxy composite fiber by measuring the maximum elongation at break during a tensile test of the composite.

[0116] The tensile strength of the resin in the fiber direction is then negligible compared to the tensile strength of the fiber, and therefore the elongation at break of the composite is considered to be that of the fiber.

[0117] ISO527-4:1997 or EN2561B type (1996) can be used.

[0118] The radius of curvature of the contact area of ​​the fibrous material must not be too small so as not to damage the fibrous material.

[0119] As a result, the curve radius must be less than or equal to the d / eps break (d / ε) or the fibrous material will be damaged.

[0120] Advantageously, each channel has up to five contact areas.

[0121] In one embodiment, particularly when the channel shape is conical, each channel is devoid of contact areas alternately located above or below the roving during its movement in the impregnation head.

[0122] Regarding thermoplastic polymers The thermoplastic polymers are selected from: polyaryletherketones (PAEK), in particular polyetheretherketones (PEEK) and polyetherketoneketones (PEKK); polyarylsulfones, in particular polyphenylenesulfones (PPSU); polyarylsulfides, in particular polyphenylene sulfide (PPS); polyamides (PA), in particular semi-aromatic polyamides (polyphthalamides), which may be modified with urea units; PEBA, polyacrylates, in particular polymethyl methacrylate (PMMA); polyolefins, in particular polypropylene, polylactic acid (PLA), polyvinyl alcohol (PVA), and fluorinated polymers, in particular polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE) or polychlorotrifluoroethylene (PCTFE); and mixtures thereof, particularly preferably from 90% to 10% by weight up to 60% to 40% by weight, in particular from 90% to 10% by weight up to 70% to 30% by weight, of PEKK and PEI.

[0123] It is clear that the thermoplastic polymer must be available in a reactive prepolymer form so that it can be impregnated into the fibrous material.

[0124] The nomenclature used to define polyamides is described in ISO Standard 1874-1:2011 "Plastiques--Materials polyamides (PA) pour moulage et extrusion--Partie 1:Designation", in particular page 3 (Tables 1 and 2), and is well known to those skilled in the art.

[0125] The polyamide may be a homopolyamide or a copolyamide or a mixture thereof.

[0126] In one embodiment, the at least one thermoplastic polymer is selected from polyamides, in particular aliphatic, cycloaliphatic, and semi-aromatic polyamides (polyphthalamides), PVDF, PEEK, PEKK, PEI, and mixtures of PEKK and PEI.

[0127] In another embodiment, the at least one thermoplastic polymer is chosen from polyamides, in particular aliphatic polyamides, cycloaliphatic polyamides, and semi-aromatic polyamides (polyphthalamides).

[0128] Advantageously, the thermoplastic polymer is a polymer having a glass transition temperature Tg of 80° C. or higher, or a semi-crystalline polymer having a melting temperature Tm of 150° C. or higher.

[0129] Advantageously, the thermoplastic polymer is an aliphatic polyamide 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), or mixtures thereof, or copolyamides thereof; Semi-aromatic polyamides, optionally modified with urea units, in particular semi-aromatic polyamides of formula X / YAr, as described in EP 1 505 099, in particular semi-aromatic polyamides of formula A / XT, in which A is chosen from units resulting from amino acids, units resulting from lactams, units corresponding to formula (Ca diamine)(Cb diacid), a represents the number of carbon atoms in the diamine and b represents the number of carbon atoms in the diacid, a and b each being between 4 and 36, advantageously between 9 and 18, the units (Ca diamine) being chosen from linear or branched aliphatic diamines, cycloaliphatic diamines and alkylaromatic diamines, and the units (Cb diacid) being chosen from linear or branched aliphatic diacids, cycloaliphatic diacids and aromatic diacids; XT refers to units resulting from the polycondensation of Cx diamines with terephthalic acid, x representing the number of carbon atoms in the Cx diamine, x being between 6 and 36, advantageously between 9 and 18, and in particular polyamides having the respective formula A / 6T, A / 9T, A / 10T or A / 11T, where A is as defined above, in particular polyamides PA6 / 6T, PA66 / 6T, PA6I / 6T, PA MPMDT / 6T, PA MXDT / 6T, PA PA11 / 10T, PA5T / 10T, PA11 / 5T / 10T, PA11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA11 / BACT / 10T, PA11 / BACT / 6T, PA11 / MPMDT / 10T, and PA11 / MXDT / 10T, and block copolymers, specifically polyamide / polyether (PEBA).

[0130] T corresponds to terephthalic acid, MXD corresponds to m-xylylenediamine, MPMD corresponds to methylpentamethylenediamine, and BAC corresponds to bis(aminomethyl)cyclohexane.

[0131] Optionally, the thermoplastic polymer or blend of thermoplastic polymers further comprises a carbon-based filler, in particular carbon black, or preferably a carbon nanofiller, in particular selected from graphene and / or carbon nanotubes and / or carbon nanofibrils, or blends thereof, which are capable of conducting electricity and heat and, as a result, can facilitate melting of the polymer matrix, in particular when heated by IR.

[0132] Of course, these carbon fillers are originally present in the reactive composition.

[0133] Regarding fibrous materials The constituent fibers of the fibrous material are in particular continuous fibers selected from carbon fibers, glass fibers, silicon carbide fibers, basalt-based fibers, silica fibers, natural fibers, in particular flax or hemp fibers, lignin fibers, bamboo fibers, sisal fibers, silk fibers, or cellulose fibers, in particular viscose fibers, or amorphous thermoplastic fibers having a glass transition temperature Tg higher than Tg of the above-mentioned polymers or polymer mixtures, if the latter are amorphous, or amorphous thermoplastic fibers having a glass transition temperature Tg higher than Tm of the above-mentioned polymers or polymer mixtures, if the latter are semi-crystalline, or semi-crystalline thermoplastic fibers having a melting point Tm higher than Tg of the above-mentioned polymers or polymer mixtures, if the latter are amorphous, or semi-crystalline thermoplastic fibers having a melting point Tm higher than Tm of the above-mentioned polymers or polymer mixtures, if the latter are semi-crystalline, or a mixture of two or more of the above-mentioned fibers, preferably carbon fibers, glass fibers, or silicon carbide fibers, in particular carbon fibers.

[0134] Advantageously, the number of fibers in said fibrous material for carbon fibers is greater than or equal to 3K, in particular greater than or equal to 6K, and in particular greater than or equal to 12K.

[0135] Advantageously, the number of fibers of said fibrous material for carbon fibers is greater than or equal to 12K, in particular selected from 12K, 24K, 48K, 50K and 400K, and in particular 12K, 24K, 48K and 50K.

[0136] Advantageously, the basis weight of the fiberglass is greater than or equal to 1,200 Tex, in particular greater than or equal to 2,400 Tex, or greater than or equal to 4,800 Tex.

[0137] Tex means yarn weight per 1000m.

[0138] These constituent fibers of the fibrous material can be used alone or in a mixture. Thus, organic fibers can be impregnated with a thermoplastic polymer and mixed with mineral fibers to form an impregnated fibrous material.

[0139] The organic fiber strands can have several basis weights. They can also have several geometries.

[0140] In one embodiment, the fibrous material is comprised of continuous carbon fibers, glass fibers, basalt or basalt-based fibers, or silicon carbide fibers, or mixtures thereof, especially carbon fibers.

[0141] The fibers of the fibrous material may be sized or unsized.

[0142] The term "sizing" refers to a surface treatment applied to fibrous materials during their manufacture. It can also refer to a transient pre-treatment at the start of a pre-impregnation step, whether or not performed directly in line with the impregnation.

[0143] The term "unsized" means that the fibers were not initially sized and therefore did not undergo a surface treatment, or that the fibers were desized prior to use.

[0144] They are generally organic (thermosetting or thermoplastic resin type) and are quite often formulated for the pre-impregnation of polymeric reinforcing fibers, either with a low melting point Tm or thermosetting with a low Tg point.

[0145] These sizings are also useful in protecting the dry fibers from damage during contact with the guide system.

[0146] The term "unsized" means that the fibers were not initially sized and therefore did not undergo a surface treatment, or that the fibers were desized prior to use.

[0147] In the case of unsized materials, the fibrous material may contain up to 0.1% by weight of an organic material (thermosetting or thermoplastic resin type) called sizing.

[0148] In the case of a transient pretreatment carried out by an impregnation device, for example, at the beginning of the process of pre-impregnation of the reinforcing fibers, the sizing may be an organic liquid, such as water, a low molecular weight alcohol, or a high molecular weight alcohol (e.g., ethanol, methanol, isopropanol), a ketone (acetone, etc.), which will function as a transient sizing; that is, it will be in contact with the fibers for a short time, allowing the sizing to be handled in a "dry" state (i.e., before pre-impregnation), and then removed from the composite material so as not to disturb the final properties of the composite.

[0149] 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.

[0150] Advantageously, the fibers of the fibrous material are sized.

[0151] Regarding impregnated fibrous materials The impregnated fibrous material has a fiber concentration of 45 to 80% by volume, preferably 50 to 65% by volume, in particular 54 to 60% by volume. Advantageously, the impregnated fibrous material has a porosity level of less than 10%, in particular less than 5%, and in particular less than 2%.

[0152] It should be noted that non-porosity levels are difficult to achieve, and as a result, advantageously, porosity levels are higher than 0%, but less than the levels listed above.

[0153] 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 the experimental density of the impregnated fibrous material described above as described in the Examples section of this application.

[0154] The molding process Optionally, a step of shaping the strands or the parallel strands of the impregnated fibrous material is performed.

[0155] In one embodiment, the method defined above further comprises shaping the parallel strand(s) of the impregnated fibrous material by at least one calender, or heated or cooled former, in the form of a single unidirectional ribbon or multiple parallel ribbons, or in the form of a U-shaped or T-shaped profile element, or in the form of a ring or multiple parallel unidirectional ribbon rings, the former being in contact or not with the impregnation head.

[0156] Advantageously, the calendering or shaping step is carried out using a plurality of hot or cold calenders or hot or cold formers mounted in parallel and / or in series relative to the passing direction of the fiber strands.

[0157] The calendering system described in WO 2015 / 121583 may be used.

[0158] Advantageously, it is carried out by calendering in the form of a single unidirectional ribbon or sheet or of a plurality of parallel unidirectional ribbons or sheets using at least one heated calender, in the latter case said heated calender comprising a plurality of calendering grooves depending on the number of said ribbons, preferably up to 200 calendering grooves, the pressure and / or the spacing between the rollers of said calender being regulated by a closed-loop control system.

[0159] Advantageously, the calendering step is carried out using a plurality of heated calenders mounted in parallel and / or in series relative to the passing direction of the fibre rovings.

[0160] Advantageously, said heating calender(s) comprise an integrated induction or microwave heating system, preferably a microwave heating system, coupled to the presence of a carbon filler in said thermoplastic polymer or mixture of thermoplastic polymers.

[0161] According to another embodiment, a belt press is between the pultrusion head and the calender.

[0162] According to yet another embodiment, a series of post-polymerization ovens is present between the pultrusion head and the last former or last calender.

[0163] Advantageously, shaping the parallel strand(s) of the impregnated fibrous material by calendering using at least one heated calender in the form of a single unidirectional ribbon or sheet or a plurality of parallel unidirectional ribbons or sheets, in the latter case the heated calender comprises a plurality of calendering grooves depending on the number of ribbons, preferably up to 300 calendering grooves, and the pressure and / or spacing between the rollers of the calender is regulated by a closed-loop control system.

[0164] Advantageously, the calendering step is carried out using a plurality of heated calenders mounted in parallel and / or in series relative to the passing direction of the fibre rovings.

[0165] Advantageously, said heating calender(s) comprise an integrated induction or microwave heating system, preferably a microwave heating system, coupled to the presence of a carbon filler in said thermoplastic polymer or mixture of thermoplastic polymers.

[0166] In one embodiment, the heating calender(s) is / are connected to a supplementary heating device located before and / or after the (respective) calender, in particular a microwave or induction heating device, or an infrared IR or laser heating device, or a device for heating by direct contact with another heat source, in particular with the presence of a carbon-based filler in the polymer or the mixture of polymers.

[0167] Regarding ribbons According to another aspect, the invention relates to a unidirectional ribbon, in particular a spooled ribbon, of impregnated fibrous material, characterized in that it is obtained using the method defined above, which includes a shaping step.

[0168] In one embodiment, the ribbon is made of a thermoplastic resin comprising an aliphatic polyamide selected from PA6, PA11, PA12, PA66, PA46, PA610, PA612, PA1010, PA1012, PA11 / 1010, or PA12 / 1010, or a semi-aromatic polyamide, such as PA MXD6 and PA MXD10, or PA6 / 6T, PA6I / 6T, PA66 / 6T, PA11 / 10T, PA5T / 10T, PA11 / 5T / 10T, PA11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 6T, PA BACT / 10T, and PA BACT / 10T / 6T, PA BACT / 10T / 11, PA The semi-aromatic polyamide is selected from BACT / 6T / 11, PVDF, PEEK, PEKK, and PEI, or a mixture thereof.

[0169] According to another aspect, the invention relates to the use of the method defined above for the production of calibrated ribbons suitable for the production of three-dimensional composite parts by automated placement of the ribbons by a robot.

[0170] In one embodiment, the ribbons of impregnated fibrous material defined above are used to manufacture three-dimensional composite parts.

[0171] In one embodiment, said manufacturing of said composite parts relates to the transport sector, in particular automotive, oil and gas, in particular offshore, gas storage, aeronautics, naval, railways; renewable energy, in particular wind energy, water turbines, energy storage devices, solar panels; thermal insulation panels; sports and entertainment, health and medicine, and electronics.

[0172] According to yet another aspect, the invention relates to a three-dimensional composite part, characterized in that it is obtained from the use of at least one unidirectional ribbon of impregnated fibrous material as defined above.

[0173] Other objects, advantages and features will become apparent from the following description, given purely by way of illustrative example, taken in conjunction with the accompanying drawings. [Example]

[0174] The following examples provide a non-limiting illustration of the scope of the present invention.

[0175] Example 1 comparison Preparation of an 11 / 6T / 10T impregnated fibrous material by non-reactive pultrusion in a single impregnation chamber but with separation of the fibers into several layers The polymer is 11 / 10T / 10T with a mass of 10,000 g / mol. Its Tg is 115° C. and its viscosity at 300° C. is 70 Pa.s.

[0176] The method for manufacturing the composite plate is pultrusion using a pultrusion head equipped with a crosshead die, with impregnation by melt means.

[0177] The pultrusion head contains a resin bath in which the fibers are separated into four layers using the system of supports described in FIG.

[0178] The pultrusion head has significant dead space.

[0179] All fiber reinforcements have a thickness of 1 mm. After separation, each layer of fiber has a thickness of about 250 μm.

[0180] The polymer is introduced into an extruder equipped with a crosshead die in the form of granules premixed with a heat stabilizer.

[0181] The temperature at which the fibers were impregnated was 300°C.

[0182] The line speed was 0.5 m / min.

[0183] The fiber used is Hypertex glass fiber 3B SE4535.

[0184] The fiber concentration was 60% by volume.

[0185] The resulting profile is a plate with a width of 200 mm and a thickness of 1 mm.

[0186] result The morphology of the obtained profile is shown in Figure 2: the impregnation of the fibers is excellent, but the line speed is low and cannot be accelerated if one wants to preserve the impregnation quality, making this pultrusion process not very productive for this type of resin.

[0187] Furthermore, the relatively low weight of the polymer used, which limits its viscosity at 300°C in view of its high Tg, prevents achieving extremely high properties at break. Therefore, the bending stress at break remains low, below 1000 MPa in view of the fiber concentration (see Table 1). This is a result of the excessively low molar mass of the resin, which was intentionally limited to 10,000 g / mol in order to have a polymer with sufficient flowability and be compatible with non-reactive processes at 300°C.

[0188] Furthermore, in FIG. 3, it is believed that this low molar mass leads to microcracking of the pultruded profile under the influence of residual stresses that appear during crystallization of the resin and cooling of the pultruded profile.

[0189] Example 2 comparison Preparation of an 11 / 6T / 10T impregnated fibrous material by reactive pultrusion in a single impregnation chamber but with separation of the fibers into several layers The same pultrusion head as in Example 1 is used, but with a reactive composition consisting of two reactive prepolymers of the 11 / 6T / 10T type, one terminated with diCOOH and the other with diNH, with a molar mass Mn of 2500 g / mol and a melt viscosity of 1 Pa.s at 300° C. After polymerization, the resin has a Tg of 115° C.

[0190] The prepolymers are melted separately using two extruders.

[0191] The prepolymer is introduced in the form of granules into an extruder equipped with a crosshead die.

[0192] The temperature at which the fibers were impregnated was 300°C.

[0193] The line speed was 0.8 m / min.

[0194] The fiber used is Hypertex glass fiber 3B SE4535.

[0195] The fiber concentration was 58% by volume.

[0196] The resulting profile is a plate with a width of 200 mm and a thickness of 1 mm.

[0197] The starting protocol for the pultrusion head is to impregnate the fibers with a single prepolymer until a stable regime is achieved on the line, then a second prepolymer is introduced and mixed with the first prepolymer at 300°C using a Sulzer-type static mixer just before being introduced into the pultrusion head.

[0198] In this pultrusion head, the fibers are separated into four layers as in Example 1. All of the fiber reinforcement has a thickness of 1 mm. After separation, each of the fiber layers has a thickness of about 250 μm.

[0199] result Although fiber impregnation is excellent, profile production stops shortly after start-up because the fibers clog the head. This is due to the presence of excessive dead space in the pultrusion head, where the reactive composition remains for a very long time and therefore polymerizes, resulting in very significant viscosification of the resin and blocking of the fibers in about 10 minutes, i.e., a time close to the polymerization time of the reactive composition and the time required to replace the initial prepolymer with the reactive composition in the dead areas. Therefore, this method is not robust and therefore not viable.

[0200] Example 3 comparison Preparation of 11 / 6T / 10T-impregnated fibrous materials by reactive pultrusion without layer separation The pultrusion head used is shown in Figure 3 and is identical to the pultrusion head design described in a study by Professor Steven Lecorre at LTN Nantes (International Journal of Microstructure and Materials Properties, January 2012). This pultrusion head is distinguished by the fact that the fibers occupy a volume close to the head volume, i.e., there is no significant dead space. However, there is no separation of the fibers into several layers, while the final profile thickness is 1 mm. The fiber concentration is 60% by volume. The thickness of the fiber reinforcement before impregnation is 1 mm, and the thickness of the pultrusion head cavity is 2.5 mm. The pultrusion speed is 0.8 m / min.

[0201] The reactive composition used consists of two reactive prepolymers of the 11 / 6T / 10T type, one terminated with diCOOH and the other with diNH, with a mass of 2500 g / mol and a melt viscosity of 1 Pa.s at 300°C. After polymerization, the resin has a Tg of 115°C.

[0202] The prepolymers are melted separately using two extruders.

[0203] The prepolymer is introduced in the form of granules into an extruder equipped with a crosshead die.

[0204] The temperature at which the fibers were impregnated was 300°C.

[0205] The line speed was 0.8 m / min.

[0206] The fiber used is Hypertex glass fiber 3B SE4535.

[0207] The fiber concentration was 59% by volume.

[0208] The resulting profile is a plate with a width of 200 mm and a thickness of 1 mm.

[0209] The starting protocol for the pultrusion head is to impregnate the fibers with a single prepolymer until a stable regime is achieved on the line, then a second prepolymer is introduced and mixed with the first prepolymer at 300°C using a Sulzer-type static mixer just before being introduced into the pultrusion head.

[0210] result The lack of excessive dead space in the pultrusion head allows the pultrusion process to continue for at least 2 hours without blockage, while the complete reaction time of the reactive composition at 300° C. is less than 5 minutes. However, despite the low viscosity of the prepolymer used, the lack of separation of the fiber reinforcement into layers does not allow for good impregnation of the fibers (see FIG. 4).

[0211] Therefore, this method is not compatible with reaction chemistries based on polymers with high Tg.

[0212] Example 4 The present invention Preparation of 11 / 6T / 10T impregnated fibrous materials by reactive pultrusion with layer separation The pultrusion head used is shown in Figure 5. This pultrusion head is distinguished by the fact that the fibers occupy a volume close to the head's volume, i.e., there is no significant dead space. Furthermore, the fibers are separated into several layers, while the final profile thickness is 1 mm. The fiber concentration is 60% by volume. Therefore, the total thickness of the fiber reinforcement is 1 mm before impregnation. Without tension, the thickness of the voids in each channel used in each layer is 350 μm, while each fiber layer has a thickness close to 250 μm under tension.

[0213] The pultrusion speed is 1.5 m / min.

[0214] The reactive composition used consists of two reactive prepolymers of the 11 / 6T / 10T type, one terminated with diCOOH and the other with diNH, with a mass of 2500 g / mol and a melt viscosity of 1 Pa.s at 300°C. After polymerization, the resin has a Tg of 115°C.

[0215] The prepolymers are melted separately using two extruders.

[0216] The prepolymer is introduced in the form of granules into an extruder equipped with a crosshead die.

[0217] The temperature at which the fibers were impregnated was 300°C.

[0218] The line speed was 1.5 m / min.

[0219] The fiber used is Hypertex glass fiber 3B SE4535.

[0220] The fiber concentration was 57% by volume.

[0221] The resulting profile is a plate with a width of 200 mm and a thickness of 1 mm.

[0222] The starting protocol for the pultrusion head is to impregnate the fibers with a single prepolymer until a stable regime is achieved on the line, then a second prepolymer is introduced and mixed with the first prepolymer at 300°C using a Sulzer-type static mixer just before being introduced into the pultrusion head.

[0223] At the exit of the pultrusion head, three IR ovens of 2 m each were installed in a row, allowing post-polymerization of the molten resin at a temperature of 300 °C. Considering a line speed of 1.5 m / min, the polymerization time was 4 min. The final shaping of the plates was carried out using a cold forming machine placed at the exit of the last polymerization oven and set at 200 °C.

[0224] result The lack of excessive dead space in the pultrusion head allows the pultrusion process to continue for at least 2 hours without clogging, while the complete reaction time of the reactive composition at 300°C is less than 5 minutes. The separation of the fiber reinforcement into layers allows for good impregnation of the fibers (see Figure 6). Furthermore, the low viscosity of the prepolymer used further allows for pultrusion speeds of 1.5 m / min, a productivity factor for this process.

[0225] Collecting a plate sample directly at the outlet of the pultrusion die made it possible to measure the molar mass of the resin at this stage of the process, revealing an Mn of 5200 g / mol (measurement carried out by NMR), confirming that the polymerization at the pultrusion head was very partial, thus limiting the risk of excessive pressure and damage to the fibers, or even complete blockage of the pultrusion head.

[0226] The use of the reactive method makes it possible to obtain, after the post-polymerization step and the final cold-molding pass, composites with excellent mechanical properties: in this case, measurements of bending stresses of more than 1000 MPa at break are carried out in accordance with ISO standard 14125:1998 (see Table 1). This reflects the fact that high molar masses are reached in the pultruded profiles, which is also accompanied by the disappearance (Figure 6) of microcracks that were present in the profiles made by the non-reactive method (Figure 3).

[0227] Furthermore, the use of reactive chemistry has made it possible to impregnate fibers at high speeds (i.e., greater than 1 m / min) and relatively low temperatures (i.e., 300°C). By comparison, and demonstrating the subject matter of the present invention, a polymer of a mass equivalent to that obtained after post-polymerization would have to be heated above 360°C using non-reactive methods to be sufficiently fluid to allow fiber impregnation. Furthermore, to avoid its decomposition, it would have to have very effective heat stabilization, which remains complex with PPA. To finish, the cost of pultrusion equipment increases significantly above 330°C.

[0228] Therefore, this reactive method is compatible with reaction chemistries based on polymers with high Tg.

[0229] Example 5 The present invention Preparation of BACT / 10T-impregnated fibrous materials by reactive pultrusion with layer separation The pultrusion head used is shown in Figure 5. This pultrusion head is distinguished by the fact that the fibers occupy a volume close to the head's volume, i.e., there is no significant dead space. Furthermore, the fibers are separated into several layers, while the final profile thickness is 1 mm. The fiber concentration was 60% by volume. Therefore, the total thickness of the fiber reinforcement was 1.2 mm before impregnation. Without tension, the thickness of the voids in each channel used in each layer was 350 μm, while under tension, each fiber layer had a thickness close to 250 μm.

[0230] The pultrusion speed is 1.5 m / min.

[0231] The reactive composition used consists of two reactive prepolymers of the BACT / 10T type, one terminated with diCOOH and the other with diNH, with a mass of 2800 g / mol and a melt viscosity of 4 Pa.s at 320° C. After polymerization, the resin has a Tg of 140° C.

[0232] The prepolymers are melted separately using two extruders.

[0233] The prepolymer is introduced in the form of granules into an extruder equipped with a crosshead die.

[0234] The temperature at which the fibers were impregnated was 320°C.

[0235] The line speed was 1.5 m / min.

[0236] The fiber used is Hypertex glass fiber 3B SE4535.

[0237] The fiber concentration was 58% by volume.

[0238] The resulting profile is a plate with a width of 200 mm and a thickness of 1 mm.

[0239] The starting protocol for the pultrusion head is to impregnate the fibers with a single prepolymer until a stable regime is achieved on the line, then a second prepolymer is introduced and mixed with the first prepolymer at 320°C using a Sulzer-type static mixer just before being introduced into the pultrusion head.

[0240] At the outlet of the pultrusion head, three IR ovens of 2 m each were installed in a row, allowing post-polymerization of the molten resin at a temperature of 320°C. Considering a line speed of 1.5 m / min, the polymerization time was 4 min. The final shaping of the plate was carried out using a cold forming machine placed at the outlet of the last polymerization oven and set at 200°C.

[0241] result The lack of excessive dead space in the pultrusion head allows the pultrusion process to continue for at least 2 hours without blockage, while the complete reaction time of the reactive composition at 320°C is less than 5 minutes. The separation of the fiber reinforcement into layers allows for good impregnation of the fibers (see Figure 7). Furthermore, the low viscosity of the prepolymer used further allows for pultrusion speeds of 1.5 m / min, which is a productivity factor for this process.

[0242] Collecting a plate sample directly at the outlet of the pultrusion die made it possible to measure the molar mass of the resin at this stage of the process, revealing an Mn of 6200 g / mol (measurement carried out by NMR), confirming that the polymerization at the pultrusion head was very partial, thus limiting the risk of excessive pressure and damage to the fibers, or even complete blockage of the pultrusion head.

[0243] The use of reactive methods makes it possible to obtain, after a post-polymerization step and a final pass through the cold moulder, composites with excellent mechanical properties: in this case, measurements of bending stresses of more than 1000 MPa at break are carried out in accordance with ISO standard 14125:1998 (see Table 1).

[0244] Furthermore, the use of reactive chemistry has made it possible to impregnate fibers at high speeds (i.e., greater than 1 m / min) and relatively low temperatures (i.e., 320°C). By comparison, and demonstrating the subject matter of the present invention, a polymer of a mass equivalent to that obtained after post-polymerization would have to be heated above 360°C using non-reactive methods to be sufficiently fluid to allow fiber impregnation. Furthermore, to avoid its decomposition, it would have to have very effective heat stabilization, which remains complex with PPA. To finish, the cost of pultrusion equipment increases significantly above 330°C.

[0245] This reactive method is compatible with reaction chemistries based on high Tg polymers. Table 1 JPEG0007745533000002.jpg36170

[0246] Example 5 Determination of porosity level and relative deviation between theoretical and experimental density (general method) a) The data requested is: - Density of the thermoplastic matrix - Fiber density - Basis weight of reinforcement For example, the linear mass (g / m) for 1 / 4 inch tape (derived from a single strand) For example, the surface density (g / m) for wider tapes or fabrics 2 ) b) Measurements performed: For the results to be representative of the material being studied, the number of samples should be at least 30. The measurements performed are: - Size of sample to be taken: Length (if linear mass is known) Length and width (if surface density is known) - Experimental density of the sample to be obtained: Mass measurement in air and water The fiber concentration is measured in accordance with ISO 1172:1999 or by thermogravimetry (TGA), for example as determined in the document B. Benzler, Applikationslabor, Mettler Toledo, Giesen, UserCom1 / 2001.

[0247] The carbon fiber concentration can be determined in accordance with ISO14127:2008.

[0248] Determination of the theoretical mass fiber concentration: a) Determination of the theoretical content by mass of fibers: JPEG0007745533000003.jpg14170In formula, ml linear mass of the tape, L is the length of the sample, and Meair: Mass of the sample measured in air

[0249] The variation in fiber content by mass is assumed to be directly related to the variation in matrix concentration, without taking into account the variation in fiber amount in the reinforcement. b) Determination of theoretical density: TIFF0007745533000004.tif19170where dm and df are the densities of the matrix and fiber, respectively.

[0250] The theoretical density thus calculated is the density that can be achieved if there are no pores in the sample. c) Porosity evaluation: Porosity is then the relative deviation between the theoretical density and the experimental density.

Claims

1. 1. A method for producing at least one impregnated fibrous material comprising a fibrous material (or roving) made of continuous fibers and at least one thermoplastic polymer having a glass transition temperature Tg of 40° C. or higher or a melting temperature Tm of 400° C. or lower, wherein the glass transition temperature Tg and the melting temperature Tm are measured by DSC in accordance with standards ISO 11357-2:2013 and ISO 11357-3:2013, respectively; the method comprising the step of impregnating the at least one fibrous material by injecting a molten reactive composition comprising at least one precursor of the thermoplastic polymer in the presence of the fibrous material at a pultrusion head; the at least one fibrous material is separated into n layers in its thickness as it enters the pultrusion head, n being 2 to 20; each layer circulates in a channel specific to it in the pultrusion head; injecting the reactive composition into each channel and / or between the layers as the layers recombine at the outlet from each channel; 10. A method for producing a fibrous material comprising: heating the channel to a temperature such that the reactive composition has an initial melt viscosity of less than 50 Pa s, the melt viscosity being measured by oscillatory rheology between two parallel flat surfaces of 25 mm diameter in a Physica MCR301 apparatus at a temperature where Tm≦T≦Tm+50° C. for semi-crystalline polymers or Tg+220° C. for amorphous polymers, at 10 rad / s under nitrogen flushing and 5% deformation; and impregnation beginning at the moment of injection and ending before or after the layers are reunited by overlapping to form the at least one final impregnated fibrous material in which the precursor of the thermoplastic polymer is at least partially polymerized.

2. 2. The method of claim 1, wherein the maximum thickness e of each layer is such that the impregnation time of each layer is less than or equal to the time required to increase the number average molecular weight (Mn) of the reactive composition in said layer by a factor of 5, as measured by size exclusion chromatography or by NMR.

3. 3. The method according to claim 1, wherein the mean residence time of the reactive composition in the head is at most equal to three times the residence time of the fibrous material.

4. 4. The method according to any one of claims 1 to 3, characterized in that the shape of the channel is cylindrical or not cylindrical.

5. 5. The method of claim 4, wherein the channels are cylindrical in shape, each channel has a thickness proportional to the thickness of each of the n layers, and the thickness of each channel is between two and three times the thickness of each of the n layers.

6. 6. The method according to claim 1, wherein each channel comprises at least one contact area having a radius of curvature greater than d / break eps (d / ε), where d is the diameter of the fibers of the fibrous material and eps is the breaking strain of the fibers, and wherein the at least one contact area is alternately arranged above or below the fibrous material (roving) during its movement in the impregnation head, in order to cause and / or maintain the spreading of the fibrous material, possibly initiated beforehand upstream of the head, without damaging the fibrous material.

7. 5. The method according to claim 1, wherein each channel is devoid of contact areas alternately located above or below the fibrous material (roving) during its movement in the impregnation head.

8. 8. The method of claim 1, wherein the reactive composition is injected between the pair of bilayers at the outlet of the channel and then impregnated into the bilayers to form an impregnated bilayer material, after which each impregnated bilayer material is assembled with the other in its thickness to form the final impregnated fibrous material.

9. 9. The method according to any one of claims 1 to 8, characterized in that the thermoplastic polymer is a reactive prepolymer capable of reacting with itself, with another prepolymer based on the molecular chain ends carried by the prepolymer, or with a chain extender.

10. 10. The method according to any one of claims 1 to 9, characterized in that the at least one thermoplastic polymer is selected from polyaryletherketones (PAEK); polyarylsulfones; polyarylsulfides; polyamides (PA); PEBA, polyacrylates; polyolefins; and mixtures thereof.

11. 11. The method according to any one of claims 1 to 10, characterized in that the at least one thermoplastic polymer is selected from polyamide, PVDF, PEEK, PEKK, PEI, and mixtures of PEKK and PEI.

12. 12. The method according to any one of claims 1 to 11, characterized in that the fiber concentration of the impregnated fibrous material is between 45 and 80% by volume.

13. 13. The method according to any one of claims 1 to 12, characterized in that the porosity level in the pre-impregnated fibrous material is less than 10%.

14. 14. The method according to any one of claims 1 to 13, further comprising shaping the one or more parallel strands of impregnated fibrous material by means of at least one calender, or a heated or cooled former, in the form of a single unidirectional ribbon or multiple parallel ribbons, or in the form of a U- or T-shaped cross-section element, or in the form of a ring or multiple parallel unidirectional ribbon rings, characterized in that the former is in contact or not with the impregnation head.

15. 15. The method according to claim 14, characterized in that the calendering or shaping step is carried out using a plurality of hot or cold calenders or hot or cold formers mounted in parallel and / or in series with respect to the passing direction of the fiber strands.

16. 16. The method of claim 15, wherein the heating calendar(s) comprises an integrated induction or microwave heating system with the presence of a carbon-based filler in the thermoplastic polymer or mixture of thermoplastic polymers.

17. 17. The method according to any one of claims 1 to 16, characterized in that a belt press is present between the pultrusion head and the calender.

18. 18. The method according to any one of claims 1 to 17, characterized in that there is a series of post-polymerization ovens between the pultrusion head and the last former or last calender.

19. 19. The method of any one of claims 1 to 18, characterized in that the thermoplastic polymer further comprises a carbon-based filler.

20. 20. The method of any one of claims 1 to 19, characterized in that the fibrous material comprises continuous fibers selected from carbon fibers, glass fibers, silicon carbide fibers, basalt-based fibers or silica fibers, natural fibers, amorphous thermoplastic fibers having a glass transition temperature Tg higher than the glass transition temperature Tg of the polymer, amorphous thermoplastic fibers having a glass transition temperature Tg higher than the melting temperature Tm of the polymer, semi-crystalline thermoplastic fibers having a melting temperature Tm higher than the Tg of the polymer, semi-crystalline thermoplastic fibers having a melting temperature Tm higher than the Tm of the polymer, or a mixture of two or more of the aforementioned fibers.

21. 21. A method for producing unidirectional ribbons of impregnated fibrous material comprising the method of any one of claims 14 to 20.

22. The thermoplastic polymer is an aliphatic polyamide selected from PA6, PA11, PA12, PA66, PA46, PA610, PA612, PA1010, PA1012, PA11 / 1010, or PA12 / 1010, or a semi-aromatic polyamide, or PA6 / 6T, PA6I / 6T, PA66 / 6T, PA11 / 10T, PA5T / 10T, PA11 / 5T / 10T, PA11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 6T, PA BACT / 10T, and PA BACT / 10T / 6T, PA BACT / 10T / 11, PA 22. The method according to claim 21, characterized in that the semi-aromatic polyamide is selected from BACT / 6T / 11, PVDF, PEEK, PEKK and PEI, or a mixture thereof.

23. 21. Use of the method according to any one of claims 14 to 20 for the production of calibrated ribbons suitable for the production of three-dimensional composite parts by automated placement of the ribbons by a robot.

24. 23. Use of the method according to claim 21 or 22 in the manufacture of three-dimensional composite parts.

25. 25. Use according to claim 23 or 24, characterized in that the manufacture of said composite parts is related to the transport sector, oil and gas, gas storage, aeronautics, naval, railways; renewable energies; thermal insulation panels; sports and leisure, health and medicine, and electronics.

26. 23. A method for manufacturing a three-dimensional composite part, comprising the method of claim 21 or 22.

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