FR3067639A1 - PROCESS FOR MANUFACTURING A COMPOSITE MATERIAL PART FROM PREPOLYMERS - Google Patents

Abstract

The invention relates to a method for manufacturing a composite material part, said material comprising reinforcing fibers and a polymer matrix, the method comprising the following steps: providing a closed mold in which reinforcing fibers are arranged ; providing a reactive composition comprising at least one prepolymer in the molten state; injection of the reactive composition into the closed mold; impregnation of the reinforcing fibers with the reactive composition in the absence of degassing; polymerization of the polymer matrix from the reactive composition in the presence of degassing; - demolding of the part.

Description

METHOD FOR MANUFACTURING A PART OF COMPOSITE MATERIAL A

FROM PREPOLYMERS

FIELD OF THE INVENTION

The present invention relates to a method for manufacturing a piece of composite material reinforced with fibers by molding from a reactive precursor composition comprising prepolymers.

TECHNICAL BACKGROUND

Composite material products such as structural parts are widely used in mechanical applications, particularly in the automotive, road, rail, marine, aeronautical or aerospace industries. They are also widely used in mechanical engineering, construction, parks and recreation or for reinforcements of shields or panels protecting against the impact of projectiles.

Document EP 0261020 describes the use of reactive semi-crystalline prepolymers based on PA 6, 11 and 12 for the manufacture of a thermoplastic composite by a pultrusion process.

Document EP 550314 describes, among its examples, (non-reactive) copolyamide compositions comprising, by mass, from 45 to 75% of PAx.T unit, x being between 4 and 12 and 25 to 55% of aliphatic unit - NH- (CH2) n-CO, n being between 6 and 14.

EP 1988113 describes a molding composition based on a 10.T / 6.T copolyamide comprising:

95% mol. of PA 10.T 5 to 40% mol. from PA 6.T.

Document WO 2011/003973 describes compositions comprising from 50 to 95 mol% of a unit based on a linear aliphatic diamine comprising from 9 to 12 carbon atoms and terephthalic acid and from 5 to 50% of uniting unit terephthalic acid to a mixture of 2,2,4 and 2,4,4 trimethylhexanediamine.

The document US 2011/0306718 describes a pultrusion process of reactive aliphatic polyamides associated with chain extenders of polymer structure carrying several functions of anhydrides or epoxides.

Document WO 2013/060976 describes a process for manufacturing a composite material based on a reactive precursor composition comprising a reactive prepolymer with identical reactive functions and a non-polymeric chain extender carrying reactive functions with the functions of said prepolymer by polyaddition.

Document WO 2014/064375 describes a reactive composition of semi-crystalline polyamide prepolymer, the elongation being carried out with a reactive precursor composition, by an extender of a different nature compared to polyamide prepolymers.

There is a need to develop a composite material having good mechanical properties (in particular a high breaking stress, including at relatively high temperature, as well as a high modulus), in which the polymer matrix has a sufficient molar mass. , as well as a fast and efficient process for obtaining such a material.

SUMMARY OF THE INVENTION

The invention relates to a method of manufacturing a part made of composite material, said material comprising reinforcing fibers and a polymer matrix, the method comprising the following steps:

- supply of a closed mold in which are placed reinforcing fibers;

- supply of a reactive composition comprising at least one prepolymer in the molten state;

- injection of the reactive composition into the closed mold;

- impregnation of the reinforcing fibers with the reactive composition in the absence of degassing;

- Polymerization of the polymer matrix from the reactive composition in the presence of degassing;

- release of the part.

According to one embodiment, the polymer matrix is a polyamide matrix and the at least one prepolymer is a polyamide prepolymer.

According to one embodiment, the reactive composition comprises:

i) either at least a first polyamide A1 prepolymer carrying two amine functions and at least one second polyamide A2 prepolymer carrying two carboxy functions, ii) or at least one polyamide A3 prepolymer carrying an amine function and a carboxy function , iii) either at least one polyamide A1 prepolymer carrying two amine functions and / or at least one polyamide A2 prepolymer carrying two carboxy functions and at least one chain extender of formula Y-A'Y, in which:

- Y is a group carrying a reactive function by polyaddition or polycondensation with at least one function of said prepolymer A1 and / or A2;

- A 'is a hydrocarbon biradical.

According to one embodiment, said chain extender of formula Y-A'-Y is a cycloaliphatic and / or aromatic dianhydride carboxylic.

According to one embodiment, the reactive composition is prepared by mixing at least two prepolymers.

According to one embodiment, the prepolymer (s) have a number-average molar mass ranging from 500 to 10,000 g / mol, preferably from 750 to 6,000 g / mol, more preferably from 750 to 3,000 g / mol and / or the matrix polymer has a number-average molar mass greater than 10,000 g / mol, preferably ranging from 10,000 to 20,000 g / mol, even more preferably from 12,000 to 17,000 g / mol.

According to one embodiment, the duration of the impregnation step is less than 15 seconds, preferably is from 1 to 10 seconds.

According to one embodiment, a degassing is applied in the closed mold before the step of injecting the reactive composition.

According to one embodiment, the degassing is carried out by the application of a vacuum ranging from 10 to 950 mbar, preferably from 700 to 900 mbar.

According to one embodiment, the reactive composition is pressurized during the impregnation step, preferably at a pressure ranging from 10 to 70 bar, even more preferably from 40 to 60 bar.

According to one embodiment, the reactive composition is pressurized during the polymerization step, preferably at a pressure which is lower than the pressure applied during the impregnation step.

According to one embodiment, the pressure applied during the polymerization step is greater than the saturation vapor pressure of the water, and preferably is 3 to 7 bar, even more preferably 4 to 6 bar.

According to one embodiment, the pressure applied during the polymerization stage is maintained until the stage of demolding the part.

According to one embodiment, the polymer matrix (and the at least one corresponding prepolymer) can be chosen from:

polymers and copolymers of the family of aliphatic, cycloaliphatic or semi-aromatic polyamides (PAs) (also called polyphthalamides (PPAs)), polyureas, in particular aromatics, polymers and copolymers of the acrylic family such as polyacrylates, and more particularly polymethyl methacrylate (PMMA) or its derivatives, polymers and copolymers of the polyarylether ketone family (PAEK) such as poly (ether ether ketone) (PEEK), or polyarylether ketone ketones (PAEKK) such as poly ( ether ketone ketone) (PEKK) or their derivatives, aromatic polyetherimides (PEI), polyarylsulfides, in particular polyphenylene sulfides (PPS), polyarylsulfones, in particular polyphenylene sulfones (PPSU), polyolefins, in particular polyolefins polypropylene (PP); polylactic acid (PLA), polyvinyl alcohol (PVA), fluorinated polymers, in particular poly (vinylidene fluoride) (PVDF), or polytetrafluoroethylene (PTFE) or polychlorotrifluoroethylene (PCTFE), and mixtures thereof.

According to one embodiment, the polymer matrix comprises units derived from one or more of the following monomers: terephthalic acid, isophthalic acid, adipic acid, sebacic acid, dodecanoic acid, 1,10- decamethylene diamine, 1,6-hexamethylene diamine, 2-methyl pentamethylene diamine (MPMD), a mixture of 2,2,4 and 2,4,4trimethylhexanediamine, 2-methyloctanediamine, nonanediamine, 4,4'diaminodicyclohexylmethane , m-xylylene diamine (mXD), 1,3-bis (aminomethyl) cyclohexyl, 1,4-bis (aminomethyl) cyclohexyl, caprolactam, amino-11 undecanoic acid, amino-12 lauric acid and / or lauryl lactam.

According to one embodiment, the polymer matrix is chosen from PA 11 / 10T, PA 11 / 6T / 10T, PA MPMDT / 10T, PA MDXT / 10T, PA BACT / 10T, PA6 / 6T, PA66 / 6T, PA6I / 6T, PA MPMDT / 6T, PA6T / 10T, PA8MT / 9T, PA TMDT / 10T, PA PACM12, PA 11 / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA MXD6 and PA MXD10, the BAC preferably being 1.3 BAC.

According to one embodiment, the polymer matrix comprises units derived from diacid monomers a), from diamine monomers b) and optionally from amino acid or lactam monomers c), and preferably:

- among the units derived from diacid monomers a), from 95 to 100%, preferably 100% by moles of the units come from terephthalic diacid and from 0 to 5% by moles of the units come from isophthalic diacid;

- among the units derived from diamine monomers b),:

from 55 to 85%, preferably from 55 to 80 mol% of the units come from a linear diamine b1) aliphatic in C9, C10, Cu or C12 and from 15 to 45%, preferably from 20 to 45% in moles of the units come from a diamine b2) different from b1), selected from: b21) an aliphatic diamine monoramified with methyl or ethyl substituent and having a difference in chain length relative to the diamine b1) associated with at least two carbons, preferably said diamine b2) being 2-methyl pentamethylene diamine, b22) m-xylylene diamine, b23) a linear aliphatic diamine in C4 to C18 when b1) is a linear aliphatic diamine in C10 to C12 and with b23 ) being a C10 to C18 diamine when said diamine b1 is a C9 diamine, and b24) 1,3-bis (aminomethyl) cyclohexyl, 1,4-bis (aminomethyl) cyclohexyl and a mixture thereof, in particular 1,3-bis (aminomethyl) cyclohexyl, and

the units derived from amino acid or lactam monomers c) are derived from C6 to C12 monomers or lactams, preferably from C6 to C11 or C12 and more preferably from Cu, said units originating from amino acid or lactams c) not representing more 30% in moles relative to the units derived from monomers a).

According to one embodiment, the polymer matrix comprises units derived from monomers b1), b2) and c) and the molar ratio of c / (b1 + b2) varies from 5 to 30%, preferably from 10 to 30%.

According to one embodiment, the polymer matrix comprises units derived from the monomers: a) terephthalic acid, b1) 1,10-decamethylene diamine, b2) 1,6-hexamethylene diamine or 2-methyl pentamethylene diamine or m-xylylene diamine or 1,3-bis (aminomethyl) cyclohexyl or 1,4-bis (aminomethyl) cyclohexyl and c) 11-amino undecanoic acid or 12-amino lauric acid or lauryl lactam; and, preferably, said polymer matrix comprises units derived from the monomers: a) terephthalic acid, b1) 1,10-decamethylene diamine, b2) 1,6-hexamethylene diamine and c) 11-amino undecanoic acid or said polymer matrix comprises units derived from the monomers: a) terephthalic acid, b1) 1,10-decamethylene diamine, b2) 1,6-hexamethylene diamine and c) 12-amino undecanoic acid.

According to one embodiment, b1) is 1,10-decamethylene diamine and b2) is chosen from 2-methyl pentamethylene diamine, m-xylylene diamine or 1,3-bis (aminomethyl) cyclohexyl or 1,4- bis (aminomethyl) cyclohexyl and a) is terephthalic acid.

According to one embodiment, the molar ratio of units derived from monomers b1 / (b1 + b2) varies from 55 to 75% and the molar ratio of units derived from monomers b2 / (b1 + b2) varies from 25 to 45 %.

According to one embodiment, said reactive composition also comprises at least one nanofiller of carbonic origin chosen from: carbon black, graphenes, carbon nanofibrils and carbon nanotubes and / or an additive.

According to one embodiment, said reinforcing fibers are selected from mineral fibers, preferably glass, carbon or basalt, in particular glass or carbon, or from synthetic fibers, preferably aramid fibers or polyaryl ether ketones, or from mixtures thereof; and / or the reinforcing fibers have a L / D ratio greater than 1000, preferably greater than 2000, L being the average length of the fibers and D their average diameter.

According to one embodiment, the part made of composite material is a structural part.

According to one embodiment, the part is a part of a road, rail, maritime, aeronautical or aerospace vehicle, or a part of a building, or a part of reinforcement of a shield or of a panel protecting against the impact of projectiles.

The present invention meets the need expressed above. More particularly, it provides a method for obtaining a part made of composite material comprising a polymer matrix of sufficient molecular weight, and in which the impregnation of the reinforcing fibers is improved, homogeneous and rapid.

This is accomplished by the specific application of degassing during the polymerization of the matrix, but not during the impregnation of the fibers.

According to the present invention, the impregnation of the reinforcing fibers by the reactive composition is carried out in the absence of degassing, which allows the achievement of an effective and homogeneous impregnation. In fact, during the injection and impregnation step, the prepolymer (s) present in the reactive composition are capable of polymerizing. This polymerization is accompanied by the release of a by-product of the reaction. This by-product not being eliminated, the polymerization is blocked and the polymerization equilibrium is shifted to low conversion rates, and leads to the production of polymer having a low number average molecular weight. The reactive composition thus keeps a low viscosity throughout the impregnation step, which facilitates it.

On the contrary, the application of degassing after the impregnation of the fibers, during the polymerization step of the polymer matrix allows the elimination of the by-product of the reaction formed, which makes it possible to obtain, during this step , of polymer of higher molar mass, thus improving the properties of the composite material. In the case of the polycondensation of a polyamide, this by-product is water.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The invention is now described in more detail and without limitation in the description which follows.

Definitions

In the present description, unless expressly indicated otherwise, all the percentages (%) indicated are molar percentages.

The viscosity in the molten state of the prepolymer or of the reactive composition is measured using a Physica MCR301 rheometer according to the reference manual of the manufacturer of this apparatus, under nitrogen sweeping at the temperature given under shear of 1 s ^-1 , between two parallel planes with a diameter of 50 mm.

The number-average molar mass of the prepolymers and of the polymer matrix can be determined from the titration of the terminal functions according to a potentiometric method (direct assay for NH 2 or COOH in the case of a matrix and polyamide prepolymers) and from theoretical functionality which is 2 (in terminal functions) for prepolymers and linear polymers prepared from bifunctional monomers alone.

The number-average molecular weights Mn can also be determined by steric exclusion chromatography or by NMR.

The glass transition temperature Tg of the polymer matrix is measured using a differential scanning calorimeter (DSC), after a second heating pass, according to ISO 11357-2: 2013. The heating and cooling rate is 20 ° C / min.

The melting temperature Tf and the crystallization temperature Te are measured by DSC, after a first heating, according to standard ISO 11357-3: 2013. The heating and cooling rate is 20 ° C / min.

The enthalpy of crystallization of the polymer matrix is measured in Differential Scanning Calorimetry (DSC) according to standard ISO 11357-3: 2013.

Polymer matrix

The composite material includes reinforcing fibers and a polymer matrix.

According to one embodiment, the polymer matrix can be chosen from: polymers and copolymers of the family of aliphatic, cycloaliphatic or semi-aromatic polyamides (PA) (also called polyphthalamides (PPA)), polyureas, in particular aromatics , polymers and copolymers of the acrylic family such as polyacrylates, and more particularly polymethyl methacrylate (PMMA) or its derivatives, polymers and copolymers of the polyarylether ketone family (PAEK) such as poly (ether ether ketone) (PEEK ), or polyarylether ketones ketones (PAEKK) such as poly (ketone ether ketone) (PEKK) or their derivatives, aromatic polyetherimides (PEI), polyarylsulfides, in particular polyphenylene sulfides (PPS), polyarylsulfones, in in particular polyphenylene sulfones (PPSU), polyolefins, in particular polypropylene (PP); polylactic acid (PLA), polyvinyl alcohol (PVA), fluorinated polymers, in particular poly (vinylidene fluoride) (PVDF), or polytetrafluoroethylene (PTFE) or polychlorotrifluoroethylene (PCTFE), and mixtures thereof.

According to an advantageous embodiment, the polymer matrix is a polyamide matrix.

According to one embodiment, the polymer matrix is a semi-crystalline polymer. A semi-crystalline polymer gives the composite material, compared to amorphous polymers, significantly improved mechanical performance, especially when hot, such as resistance to creep or fatigue.

According to a particular embodiment, the polymer matrix is a thermoplastic matrix.

Advantageously, the polymer matrix has a glass transition temperature Tg of at least 80 ° C, preferably at least 90 ° C, more preferably at least 100 ° C and even more preferably at least 120 ° C. A glass transition temperature greater than or equal to 80 ° C. ensures good mechanical properties of the composite over the entire operating temperature range, for example up to 90 ° C. for wind power, up to 100 ° C. for l automotive and up to 120 ° C for aeronautics.

According to an even more advantageous embodiment, the polymer matrix has a melting temperature Tf greater than 200 ° C, preferably greater than 220 ° C. A melting temperature above 200 ° C allows compatibility with cataphoresis treatments, in particular in the automotive industry. Preferably, the melting temperature Tf is less than or equal to 320 ° C and even more preferably less than 290 ° C. A melting temperature above 320 ° C. requires the composite material to be used at higher temperatures, which imposes constraints on the molding material and associated heating system and leads to energy overconsumption. The use at such high temperatures increases the risks of thermal degradation of the polymer resulting in the degradation of the properties of the final matrix and therefore of the composite material and of the final composite part.

According to one embodiment, the polymer matrix has a crystallization temperature Te such that the difference between the melting temperature Tf of the matrix and of crystallization Te, Tf-Tc, does not exceed 60 ° C, preferably does not exceed 50 ° C and more particularly does not exceed 40 ° C.

According to a particular variant, the enthalpy of crystallization of the polymer matrix is greater than 40 J / g, preferably greater than 45 J / g.

The mechanical performance or mechanical resistance to heat of the composite material can be evaluated by the variation of the breaking stress in bending in the direction of the fibers (or in English, “maximum strength at 0 °”) between the ambient temperature (23 ° C. ) and 100 ° C, good mechanical strength when hot, corresponding to maintaining at least 75% of the mechanical performance, in terms of breaking stress, compared to that at room temperature (23 ° C).

According to the invention, the polymer matrix is prepared by mass polymerization of the reactive composition comprising at least one prepolymer in the molten state.

Advantageously, the polymer matrix has a number-average molar mass greater than 10,000 g / mol, preferably ranging from 10,000 to 20,000 g / mol, even more preferably from 12,000 to 17,000 g / mol.

According to one embodiment, the polymer matrix is a polyamide matrix which comprises units derived from the following monomers: terephthalic diacid, isophthalic diacid, adipic acid, sebacic acid, dodecanoic acid, 1,10- decamethylene diamine, 1,6-hexamethylene diamine, 2-methyl pentamethylene diamine (MPMD), a mixture of 2,2,4 and 2,4,4trimethylhexanediamine (TMD), 2-methyloctanediamine (8M), nonanediamine, 4,4'-diaminodicyclohexylmethane (PACM) m-xylylene diamine (mXD), 1,3bis (aminomethyl) cyclohexyl (1,3 BAC), 1,4-bis (aminomethyl) cyclohexyl (1,4 BAC) , caprolactam, amino-11 undecanoic acid, amino-12 lauric acid and / or lauryl lactam.

According to an advantageous embodiment, the polymer matrix is a polyamide matrix which is chosen from PA 11 / 10T, PA 11 / 6T / 10T, PA MPMDT / 10T, PA MDXT / 10T, PA BACT / 10T, PA 6 / 6T, PA 66 / 6T, PA 6I / 6T, PA MPMDT / 6T, PA 6T / 10T, PA 8MT / 9T, PA TMDT / 10T, PA PACM12, PA 11 / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA MXD6 and PA MXD10, the BAC being advantageously 1.3 BAC.

Reactive composition

The reactive composition comprises one or more prepolymers capable of reacting with each other during the polymerization step, to provide the matrix described above.

In an advantageous embodiment, the prepolymer (s) are polyamide prepolymers.

Each prepolymer is itself a polymer (homopolymer or copolymer), having a number-average molar mass less than that of the matrix. According to one embodiment, the prepolymer (s) included in the reactive composition have a number-average molar mass ranging from 500 to 10,000 g / mol, preferably from 750 to 6,000 g / mol, more preferably from 750 to 3,000 g / mol .

According to one embodiment, when at least two prepolymers are used, these have substantially the same number-average molar mass. By “substantially the same number average molar mass”, it is meant that the difference between the two masses is less than 20%.

According to a first embodiment, the composition comprises at least a first polyamide A1 prepolymer carrying two amine functions and at least one second polyamide A2 prepolymer carrying two carboxy functions co-reactive with the amine functions of the first polyamide prepolymer. The backbones of the prepolymers A1 and A2 can be of the same nature (that is to say have the same composition in repeated units), or of a different nature. Preferably, they are of the same nature.

According to a second embodiment, the composition comprises at least one polyamide A3 prepolymer carrying an amine function and a co-reactive carboxy function between them. In this embodiment, the composition may comprise a single polyamide prepolymer carrying an amine function and a carboxy function co-reactive with each other, or else several different prepolymers, each carrying an amine function and a carboxy function. In the latter case, the skeletons of the various prepolymers A3 may be of the same nature (the various prepolymers A3 then being distinguished only by a distinct number average molar mass), or of different nature.

According to a third embodiment, the composition comprises at least one prepolymer A1 carrying two amine functions (as described above) and / or at least one polyamide A2 prepolymer carrying two carboxy functions (as described above) and at least one chain extender of formula Y-A'-Y, in which

Y is a group carrying a reactive function by polyaddition or polycondensation with at least one function of said prepolymer A1 and / or A2;

A 'is a hydrocarbon biradical.

When the prepolymer carries two NH2 functions (amine functions):

- either the chain extender Y-A'-Y is such that • Y is chosen from the groups: maleimide, optionally blocked isocyanate, oxazinone and oxazolinone, preferably oxazinone and oxazolinone and • A 'is a carbonaceous spacer or carbon radical chosen from:

• a covalent bond between two functions (groups) Y in the case where Y is an oxazinone or oxazolinone group, or • an aliphatic hydrocarbon chain or an aromatic and / or cycloaliphatic hydrocarbon chain, the latter two comprising at least one cycle of 5 or 6 carbon atoms optionally substituted, with optionally said aliphatic hydrocarbon chain having a molecular weight of 14 to 200 g.mol '¹;

either the chain extender Y-A’-Y is such that Y is a caprolactam group and A can be a carbonyl radical such as carbonyl biscaprolactam or A ’can be a terephthaloyl or an isophthaloyl,

- Either said chain extender Y-A'-Y carries a group Y of cyclic anhydride and preferably this extender is chosen from a cycloaliphatic and / or aromatic dianhydride and more preferably it is chosen from: ethylene tetracarboxylic dianhydride, dianhydride pyromellitic, dianhydride 3.3 ', 4.4'biphenyltetracarboxylic, dianhydride 1,4,5,8naphthaletetetracarboxylic, dianhydride perylenetetracarboxylic, dianhydride 3.3', 4,4'-benzophenone tetracarboxylic, dianhydride 1,2, 3,4-cyclobutanetetracarboxylic, hexafluoroisopropylidene bisphthalic dianhydride, dianhydride 9.9bis (trifluoromethyl) xanthenetetracarboxylic, 3.3 'dianhydride, 4,4'diphenylsulfonetetracarboxylic, bicyclo dianhydride [2.2.2] oct-7 -2 5,6-tetracarboxylic, 1,2,3,4cyclopentanetetracarboxylic dianhydride, 3,3 ', 4,4'-diphenyl ether tetracarboxylic dianhydride or mixtures thereof.

When the prepolymer carries two COOH functions (carboxy functions), said chain extender Y-A’-Y is such that:

• Y is chosen from the groups: oxazoline, oxazine, imidazoline or aziridine, such as 1, l'-iso- or terephthaloyl-bis (2-methyl aziridine), • A is a carbonaceous (radical) spacer as defined above.

In all of the above statements, A may in particular represent an alkylene biradical such as - (CH2) m- with m ranging from 1 to 14 and preferably from 2 to 10 or a cycloalkylene and / or arylene substituted or unsubstituted biradical substituted, such as benzene arylenes, such as phenylenes o-, m-, p- or naphthalene arylenes.

According to one embodiment, the reactive composition is prepared by mixing at least two prepolymers.

Preferably, the method comprises a preliminary step of heating the prepolymer (s), to a temperature higher than the melting temperature of the prepolymers. Preferably, the heating temperature applied is from 200 to 350 ° C, in particular from 230 to 320 ° C, and more particularly from 250 to 300 ° C.

Preferably, at least two prepolymers are used, in which case the method comprises a step of mixing the prepolymers in the molten state, for example by means of a static mixer, a dynamic mixer, or a type mixer. RIM (in English, "reactive injection molding") to form the composition intended to be injected into the mold.

The prepolymers (in particular polyamides) can be prepared in a manner known to those skilled in the art by polymerization from respective monomers, the polymerization being able to be stopped when the desired molar mass is reached, for example by controlling the water pressure (progress of the reaction) and / or amounts of monomers. The prepolymers A1 and A2 carrying two amine functions or two extreme carboxy functions can for example be obtained by using an excess of diamine monomer, respectively an excess of diacid monomer.

The manufacture of such reactive prepolymers is for example described in the document WO 2014/064375.

Preferably, the prepolymers contained in the reactive composition and the polymer matrix obtained by polymerization of said reactive composition have the same composition in units derived from the monomers a), b) and optionally c).

According to a particular embodiment, the prepolymers A1 and / or A2 or the prepolymer A3 comprise units derived from the monomers: a) terephthalic acid, b1) 1,10-decamethylene diamine and b2) MPMD or mXD.

According to another particular embodiment, the prepolymers A1 and / or A2 or the prepolymer A3 comprise units derived from the monomers: a) terephthalic acid, b1) 1,10-decamethylene diamine and b2) 1,3-bis (aminomethyl) cyclohexyl (1.3 BAC), 1,4-bis (aminomethyl) cyclohexyl (1.4 BAC) or a mixture thereof, in particular 1,3-bis (aminomethyl) cyclohexyl (1.3 BAC).

According to another particular embodiment, the prepolymers A1 and / or A2 or the prepolymer A3 comprise units derived from the monomer c), the latter being chosen from amino-11 undecanoic acid, amino-12 lauric acid and lauryl lactam.

According to a more particular embodiment, the prepolymers A1 and / or A2 or the prepolymer A3 comprise units derived from the monomers: a) terephthalic acid, b1) 1,10-decamethylene diamine, b2) 1,6-hexamethylene diamine or

MPMD or mXD or 1.3 BAC or 1.4 BAC and c) 11-amino undecanoic acid or 12-amino lauric acid or lauryl lactam.

According to an even more particular embodiment, the prepolymers A1 and / or A2 or the prepolymer A3 comprise units derived from the monomers: a) terephthalic acid, b1) 1,10-decamethylene diamine, b2) 1,6-hexamethylene diamine or MPMD or mXD or 1.3 BAC or 1.4 BAC and c) 11-amino undecanoic acid.

According to an even more particular embodiment, the prepolymers A1 and / or A2 or the prepolymer A3 comprise units derived from the monomers: a) terephthalic acid, b1) 1,10-decamethylene diamine, b2) 1,6-hexamethylene diamine and c) 11-amino undecanoic acid.

According to another particular embodiment, the prepolymers A1 and / or A2 or the prepolymer A3 comprise units derived from the monomers: a) terephthalic acid, b1) 1,10-decamethylene diamine, b2) 1,6-hexamethylene diamine and c ) amino-12 undecanoic acid.

In the embodiments in which units originating from the monomer c) are present, the reactive composition has a lower viscosity in the molten state compared to the same composition without units originating from c), with average molar mass in comparable number . This allows a significant improvement in the impregnation of the reinforcing fibers. Alternatively, for a constant melt viscosity, the presence of units from c) makes it possible to have higher average molecular weights in number of prepolymers.

The reactive composition may comprise at least one nanofiller of carbonic origin. Preferably, the nanofiller is chosen from: carbon black, graphenes, carbon nanofibrils and carbon nanotubes.

The reactive composition may include one or more other additives.

The additives can be an additive which absorbs UV, infrared (IR), microwave or induction radiation. Such an additive can be used to heat the composite material or the part made of composite material, before, for example, a complementary transformation operation, in particular a heat-stamping or an overmolding.

The additives can also be a specific additive such as thermal stabilizers, in particular these stabilizers are antioxidants against thermo-oxidation and / or photo-oxidation of the polymer of the thermoplastic matrix and are organic or inorganic stabilizers.

The expression “organic stabilizer” or more generally a “combination of organic stabilizers” denotes a primary antioxidant of the phenol type, a secondary antioxidant of the phosphite type and even possibly other stabilizers such as a HALS, which means Hindered Amine Light Stabilizer or light stabilizer of the hindered amine type (for example Tinuvin 770 from the company Ciba), an anti-UV (for example Tinuvin 312 from the company Ciba), a phenolic stabilizer or based on phosphorus. Amine-type antioxidants such as Naugard 445 from the company Crompton or polyfunctional stabilizers such as Nylostab S-EED from the company Clariant can also be used.

The organic stabilizer present can be chosen, without this list being restrictive, from:

- phenolic antioxidants, for example Irganox 245, Irganox 1010, Irganox 1098 from Ciba, Irganox MD1024 from Ciba, Lowinox 44B25 from Great Lakes, ADK Stab AO-80 from Adeka Palmarole.

stabilizers based on phosphorus, such as phosphites, for example Irgafos 168 from the company Ciba,

- a UV absorber, such as Tinuvin 312 from Ciba,

- a HALS, as previously mentioned,

an amine type stabilizer, such as Naugard 445 from the company Crompton, or also a hindered amine type such as Tinuvin 770 from the company Ciba,

- a polyfunctional stabilizer such as Nylostab S-EED from Clariant.

It is obviously possible to envisage a mixture of two or more of these organic stabilizers.

The expression “mineral stabilizer” designates a stabilizer based on copper or based on a metal oxide as described in document US 2008/0146717. By way of example of such mineral stabilizers, mention may be made of copper halides and acetates or iron oxides such as FeO, Fe2O3, Fe3O4 or a mixture of these. Incidentally, we can possibly consider other metals such as silver, but these are known to be less effective.

These mineral stabilizers are more particularly used when the structures must have an improved long-term thermal resistance in hot air, in particular for temperatures greater than or equal to 100 or even 120 ° C., because they tend to prevent cuts in polymer chains. .

More particularly, the term “copper-based stabilizer” means a compound comprising at least one copper atom, in particular in ionic form, or ionizable form, for example in the form of a complex.

The copper-based stabilizer can be chosen from cuprous chloride, cupric chloride, cuprous bromide, cupric bromide, cuprous iodide, cupric iodide, cuprous acetate and cupric acetate. Mention may be made of halides, acetates of other metals such as silver in combination with the copper-based stabilizer. These copper-based compounds are typically associated with alkali metal halides, in particular potassium. A well-known example is the mixture of Cul and Kl, where the Cul: Kl ratio is typically from 1: 5 to 1:15. An example of such a stabilizer is the Polyad P201 from the company Ciba.

More details on copper-based stabilizers can be found in US 2,705,227. More recently, copper-based stabilizers have appeared, such as complexed copper such as the Bruggolen H3336, H3337, H3373 from the company Brüggemann.

Advantageously, the copper-based stabilizer is chosen from copper halides, copper acetate, copper halides or copper acetate mixed with at least one alkali metal halide, and mixtures thereof, preferably the mixtures of copper iodide and potassium iodide (Cul / KI).

The additive can also be an impact modifier, advantageously consisting of a polymer having a flexural modulus of less than 100 MPa measured according to ISO standard 178 and of glass transition temperature Tg of less than 0 ° C (measured according to standard 11357-2 : 2013 at the inflection point of the DSC thermogram), in particular a polyolefin, coupled or not with a Peba (polyether block amide) having a flexural modulus <200 MPa.

The polyolefin of the impact modifier can be functionalized or non-functionalized or be a mixture of at least one functionalized polyolefin and / or at least one non-functionalized polyolefin.

The additives can also be halogen-free flame retardants, as described in document US 2008/0274355 and in particular a metal salt chosen from a metal salt of phosphinic acid and a metal salt of diphosphinic acid, a polymer containing at at least one metal salt of phosphinic acid, a polymer containing at least one metal salt of diphosphinic acid or red phosphorus, an antimony oxide, a zinc oxide, an iron oxide, a magnesium oxide or metallic borates such as a zinc borate or else melamine pyrophosphates and melamine cyanurates. They can also be halogenated flame retardants such as a brominated or polybrominated polystyrene, a brominated polycarbonate or a brominated phenol.

Advantageously, the additive is chosen from an antioxidant, a heat stabilizer, a UV absorber, a light stabilizer, an impact modifier, a lubricant, an inorganic filler, a flame retardant, a nucleating agent, in particular a mineral filler such as talc, and a dye.

The nanofillers and additives can be added to the prepolymer (s) in the molten state to form the reactive composition before injection of the latter into the mold.

Reinforcement fibers

According to one embodiment, the fibers are selected from mineral fibers, preferably glass, carbon or basalt, in particular glass or carbon or from synthetic fibers, preferably aramid or polyaryl ether fibers ketones, or mixtures thereof.

Advantageously, the fibers have a length such that the L / D ratio is greater than 1000, preferably greater than 2000, L being the average length of the fibers and D their average diameter, determined by methods well known to those skilled in the art. , especially by microscopy.

The fibers can represent from 45 to 75% by volume of the composite material, preferably from 50 to 70%.

Process steps

The method of the invention is implemented in a mold, which is a closed mold. Advantageously, the mold is integrated in a press making it possible to apply pressure to the reactive composition in the mold. The mold is also provided with a degassing system, that is to say suction of the gases present in the enclosure of the mold, comprising at least one pump and one or more vents opening into the enclosure of the mold. Advantageously, the impregnation step has a duration of less than 15 seconds. Preferably, the duration of this step ranges from 1 to 10 seconds. A short duration of impregnation makes it possible to limit the polymerization of the prepolymers of the reactive composition during this stage, which improves the impregnation of the fibers.

The impregnation step is carried out in the absence of degassing, that is to say that no vacuum is applied in the vents of the degassing system and that there is no suction of gases present in the mold enclosure.

According to a particular embodiment, the reactive composition during the impregnation step has a viscosity of less than 100 Pa.s, preferably less than 50 Pa.s, more preferably less than 10 Pa.s.

In a particular embodiment, the injection of the reactive composition into the closed mold and the impregnation of the reinforcing fibers are simultaneous. In this embodiment, injection and impregnation are carried out in the absence of degassing.

According to another embodiment, the injection of the reactive composition is carried out in a closed mold comprising an open compression chamber, preferably in the absence of degassing during the injection, then the impregnation of the reinforcing fibers by the reactive composition is carried out during the compression induced by the closure of the compression chamber, in the absence of degassing during said compression.

According to a particular embodiment, the temperature applied in the mold during the polymerization step is higher than the crystallization temperature Te of the polymer matrix.

According to one embodiment, the polymerization temperature is higher than the crystallization temperature of the polymer prepolymer having the highest crystallization temperature, preferably at least 5 ° C higher.

Preferably, the applied temperature is from 200 to 350 ° C, in particular from 230 to 320 ° C, and more particularly from 250 to 300 ° C.

According to a particular embodiment, the method according to the invention comprises a degassing step in the mold before the injection step. The application of this degassing allows the elimination in the mold of all or part of the air and / or any other substance whose presence could be detrimental to the manufacture of the part made of composite material. Indeed, degassing of the fibers in the closed mold carried out before the start of the injection of the resin into the mold makes it possible to reduce the porosities linked to air bubbles. The vacuum system is then closed to allow injection of the reactive resin under the conditions limiting the polymerization described above.

The degassing (s), that is to say the degassing carried out during the polymerization stage, and when it is present, the degassing carried out before the injection stage, can independently be carried out with a vacuum ranging from 10 to 950 mbar, preferably 700 to 900 mbar, relative to atmospheric pressure. As regards degassing during the polymerization step, the vents have a sufficiently small diameter and the reactive composition is sufficiently viscous for a pressure drop to be created at the vents preventing the reactive composition from passing through the vents and to come out of the mold.

According to one embodiment, the method according to the invention is an RTM process (resin transfer molding or "Resin Transfer Molding") or c-RTM process (resin transfer molding or "Resin Transfer Molding" with compression). Advantageously, the process according to the invention is a c-RTM process (resin transfer molding or "Resin Transfer Molding" with compression). In such a process, the injection and impregnation steps are separated, and the impregnation is done during a mold compression step.

According to a particular embodiment, a pressure is applied to the reactive composition during the impregnation step. This pressure improves the impregnation of the fibers by the reactive composition. Preferably, the pressure is from 10 to 70 bar, even more preferably from 40 to 60 bar.

According to a preferred embodiment, a pressure is applied to the reactive composition during the polymerization step (independently of the vacuum applied in the vents of the degassing system). This pressure is also called in the present patent application "holding pressure". Advantageously, this pressure is lower than the pressure applied during the impregnation step. In a particularly preferred manner, this pressure is greater than the saturated vapor pressure of water. By "the saturated vapor pressure of water" is meant the saturated vapor pressure of water at the temperature of the reactive composition inside the mold. The application of a holding pressure higher than the saturated vapor pressure of water prevents the water formed as a by-product during polymerization from bubbling, which would degrade the quality of the composite material. The pressure applied during the polymerization step must however be low enough so that the reactive composition does not pass through the vents during the application of degassing. Preferably, the pressure applied during the polymerization step is from 3 to 7 bar, even more preferably from 4 to 6 bar.

The pressure during the polymerization can be applied by a means different from that applying the pressure during the impregnation step. For example, if the pressure during the impregnation step is applied by a press, the mold can be removed from the press after the impregnation step, and inserted into a second press for the polymerization step, advantageously provided of a degassing system as described above.

According to a particular embodiment, the pressure applied during the polymerization stage is maintained until the stage of demolding of the part.

According to a particular embodiment, the degassing is applied for substantially the entire duration of the polymerization step (with the exception, for example, of the possible displacement of the mold from one press to another).

According to another particular embodiment, the degassing is applied throughout the duration of the polymerization step. When the mold is moved from one press to another press, or to a former, the residual pressure in the mold is maintained by vacuum (vacuum of 700 to 900 mbar typically).

Preferably, the mold is heated during the polymerization step. Preferably, the temperature applied is from 200 to 350 ° C, in particular from 230 to

320 ° C, and more particularly from 250 to 300 ° C.

The duration of the polymerization step is preferably less than 15 min, preferably less than 10 min, more preferably less than 5 min.

The method according to the invention may include a step of cooling the part made of composite material produced, for example to room temperature. Preferably, demolding is carried out at high temperature, at a temperature below the crystallization temperature Te.

The process according to the invention can comprise an additional post-polymerization step, in the solid state or in the molten state. This step is carried out in the mold or outside the mold, if there is a need to perfect the polymerization in the case where the polymerization defined above is not complete. Preferably, this post-polymerization is carried out in the mold placed under a second press or on a former, in the molten state, at a temperature higher than the crystallization temperature of the polymer. According to a preferred option, there is no post-polymerization.

According to one embodiment, the method allows the manufacture of a structural part based on the composite material.

The part may be a part of a road, rail, maritime, aeronautical or aerospace vehicle, or a part of a building, or a part of reinforcement of a shield or panel for protection against the impact of projectiles.

In particular, the structural part may be an automotive part, possibly inserted into a metallic structure such as the blank body of a vehicle, said metallic structure with the inserted composite structural part possibly being subjected to a thermochemical treatment cycle by cataphoresis.

EXAMPLES

The following examples illustrate the invention without limiting it.

Methods for determining the cited characteristics

The titration (assay) of the terminal functions is carried out according to a potentiometric method (direct assay for NH2 or COOH).

The glass transition temperature Tg is measured using a differential scanning calorimeter (DSC), after a second heating pass, according to ISO 11357-2: 2013. The heating and cooling rate is 20 ° C / min.

The melting temperature Tf and the crystallization temperature Te are measured by DSC, according to ISO standard 11357-3: 2013. The heating and cooling rate is 20 ° C / min.

The enthalpy of fusion of said matrix polymer is measured in Differential Scanning Calorimetry (DSC), after a second heating pass, according to ISO 11357-3: 2013.

Preparation of functionalized oligomers (prepolymers)

5 kg of the following raw materials are introduced into an autoclave reactor of 14 liters:

- 500 g of water,

- the diamine (s),

- the amino acid (possibly),

- the diacid (s),

- 35 g of sodium hypophosphite in solution,

- 0.1 g of a WACKER AK1000 defoamer (company Wacker Silicones).

The closed reactor is purged of its residual oxygen and then heated to a temperature of 230 ° C of the material. After 30 minutes of stirring under these conditions, the pressurized vapor which has formed in the reactor is gradually expanded in 60 minutes, while gradually increasing the material temperature so that it becomes established at the temperature of melting Tf + 10 ° C at atmospheric pressure.

The oligomer (prepolymer) is then drained by the bottom valve then cooled in a water tank and then ground.

The nature, the molar ratio of the units and the molecular structure of the polyamide oligomers synthesized, as well as their main characteristics, are given in Table 1 below.

Structure molecular and composition molar functionality Tf ° C Tg ° C You ° C ΔΗ J / g Index acid eq / T Index amine eq / T oligomer 1 11 / 6T / 10T 16/24/60 nh ₂ 269.2 81.7 234.8 69.8 0 620 oligomer 2 11 / 6T / 10T 9.1 / 27.3 / 63.6 COOH 263.3 97 228 56 711 0

Table 1: Characteristics of the synthesized functionalized oligomers

Comparative example 1

A c-RTM test is carried out using the two oligomers 1 and 2, mixed using a static mixer of the SMX type from Sulzer in a 50/50 molar ratio, in a mold heated to 280 ° C. containing 4 plies of woven glass fibers.

The two polymers are melted beforehand in independent pots 5 heated to 280 ° C.

A slight vacuum is applied to extract any air from the jars before fusion and injection, then has been cut before injection and impregnation.

After injection (approximately 10 s), a compression of the mold at 50 bar is carried out and maintained until release.

o After 10 minutes at 280 ° C, the mold is cooled in the open air and the part obtained is removed from the mold at 180 ° C.

The molar mass of this sample, determined by NMR, is close to 7300 g / mol.

Example 1 (according to the invention)

A c-RTM test is carried out using the two oligomers 1 and 2, mixed using a static mixer of the SMX type from Sulzer in a 50/50 molar ratio, in a mold heated to 280 ° C. containing 4 plies of woven glass fibers.

The two polymers are melted beforehand in independent pots heated to 280 ° C.

A slight vacuum is applied to extract any air from the jars before fusion and injection, then has been cut before injection and impregnation.

After injection (approximately 10 s), a compression of the mold at 50 bar is carried out for 3 minutes then reduced to 5 bar and maintained for 7 minutes.

A high vacuum (10 mbar) is applied after the pressure has been reduced to 5 bar and the mold is cooled in the open air. The part obtained is removed from the mold at 180 ° C.

The molar mass of this sample determined by NMR is however much higher, close to 11500 g / mol.

Claims (24)

1. Method for manufacturing a part made of composite material, said material comprising reinforcing fibers and a polymer matrix, the method comprising the following steps: - supply of a closed mold in which are placed reinforcing fibers; - supply of a reactive composition comprising at least one prepolymer in the molten state; - injection of the reactive composition into the closed mold; - impregnation of the reinforcing fibers with the reactive composition in the absence of degassing; - Polymerization of the polymer matrix from the reactive composition in the presence of degassing; - release of the part. 2. Method according to claim 1, in which the polymer matrix is a polyamide matrix and the at least one prepolymer is a polyamide prepolymer. 3. Method according to claim 2, in which the reactive composition comprises: i) either at least a first polyamide A1 prepolymer carrying two amine functions and at least one second polyamide A2 prepolymer carrying two carboxy functions, ii) or at least one polyamide A3 prepolymer carrying an amine function and a carboxy function , iii) either at least one polyamide A1 prepolymer carrying two amine functions and / or at least one polyamide A2 prepolymer carrying two carboxy functions and at least one chain extender of formula Y-A'-Y, in which: - Y is a group carrying a reactive function by polyaddition or polycondensation with at least one function of said prepolymer A1 and / or A2; - A 'is a hydrocarbon biradical. 4. The method of claim 3, wherein said chain extender of formula Y-A'-Y is a cycloaliphatic and / or aromatic dianhydride carboxylic. 5. Method according to one of claims 1 to 4, wherein the reactive composition is prepared by mixing at least two prepolymers. 6. Method according to one of claims 1 to 5, in which the prepolymer (s) have a number-average molar mass ranging from 500 to 10,000 g / mol, preferably from 750 to 6000 g / mol, more preferably from 750 to 3000 g / mol and / or the polymer matrix has a number-average molar mass greater than 10,000 g / mol, preferably ranging from 10,000 to 20,000 g / mol, even more preferably from 12,000 to 17,000 g / mol. 7. Method according to one of claims 1 to 6, wherein the duration of the impregnation step is less than 15 seconds, preferably is 1 to 10 seconds. 8. Method according to one of claims 1 to 7, wherein a degassing is applied in the closed mold before the step of injecting the reactive composition. 9. Method according to one of claims 1 to 8 wherein the degassing is carried out by the application of a vacuum ranging from 10 to 950 mbar, preferably from 700 to 900 mbar. 10. Method according to one of claims 1 to 9, wherein the reactive composition is pressurized during the impregnation step, preferably at a pressure ranging from 10 to 70 bar, even more preferably from 40 to 60 bar . 11. The method of claim 10, wherein the reactive composition is pressurized during the polymerization step, preferably at a pressure which is lower than the pressure applied during the impregnation step. 12. The method of claim 11, wherein the pressure applied during the polymerization step is greater than the saturated vapor pressure of water, and preferably is from 3 to 7 bar, even more preferably from 4 to 6 bar . 13. The method of claim 11 or 12, wherein the pressure applied during the polymerization step is maintained until the release step of the part. 14. Method according to one of claims 1 to 13, wherein the polymer matrix comprises units derived from one or more of the following monomers: terephthalic acid, isophthalic acid, adipic acid, sebacic acid, l dodecanoic acid, 1,10-decamethylene diamine, 1,6hexamethylene diamine, 2-methyl pentamethylene diamine (MPMD), a mixture of 2,2,4 and 2,4,4-trimethylhexanediamine, 2-methyloctanediamine, nonanediamine, 4,4'diaminodicyclohexylmethane, m-xylylene diamine (mXD), 1,3-bis (aminomethyl) cyclohexyl, 1,4-bis (aminomethyl) cyclohexyl, caprolactam, amino-11 acid undecanoic, amino-12 lauric acid and / or lauryl lactam. 15. Method according to one of claims 1 to 14, in which the polymer matrix is chosen from PA 11 / 10T, PA11 / 6T / 10T, PA MPMDT / 10T, PA MDXT / 10T, PABACT / 10T , PA 6 / 6T, PA 66 / 6T, PA 6I / 6T, PA MPMDT / 6T, PA 6T / 10T, PA 8MT / 9T, PA TMDT / 10T, PA PACM12, PA 11 / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA MXD6 and PA MXD10, the BAC being preferably 1.3 BAC. 16. Method according to one of claims 1 to 14, in which the polymer matrix comprises units derived from diacid monomers a), from diamine monomers b) and optionally from amino acid or lactam monomers c), and preferably: - among the units derived from diacid monomers a), from 95 to 100%, preferably 100% by moles of the units come from terephthalic diacid and from 0 to 5% by moles of the units come from isophthalic diacid; - among the units derived from diamine monomers b),: from 55 to 85%, preferably from 55 to 80% in moles of the units come from a linear diamine b1) aliphatic in C9, C10, C11 or C12 © t from 15 to 45%, preferably from 20 to 45% in moles of the units come from a diamine b2) different from b1), selected from: b21) a monoramified aliphatic diamine with methyl or ethyl substituent and having a chain length difference with respect to the diamine b1) associated with at least two carbons, preferably said diamine b2) being 2-methyl pentamethylene diamine, b22) m-xylylene diamine, b23) a linear aliphatic diamine in C4 to C18 when b1) is a linear aliphatic diamine in C10 to C12 and with b23) being a diamine in C10 to C18 when said diamine b1 is a diamine in C9, and b24) 1,3-bis (aminomethyl) cyclohexyl, 1,4-bis (aminomethyl) cyclohexyl and a mixture thereof, in particular 1,3-bis (aminomethyl) cyclohexyl, and - The units derived from amino acid or lactam monomers c) are derived from C6 to C12 monomers or lactams, preferably Cô, Ch or C12 and more preferably C11, said units derived from amino acid or lactam c) monomers not representing more 30% in moles relative to the units derived from monomers a). 17. The method of claim 16, wherein the polymer matrix comprises units derived from monomers b1), b2) and c) and the molar ratio of c / (b1 + b2) varies from 5 to 30%, preferably from 10 at 30%. 18. The method of claim 16 or 17, wherein the polymer matrix comprises units derived from the monomers: a) terephthalic acid, b1) 1,10-decamethylene diamine, b2) 1,6hexamethylene diamine or 2-methyl pentamethylene diamine or m -xylylene diamine or 1,3-bis (aminomethyl) cyclohexyl or 1,4-bis (aminomethyl) cyclohexyl and c) 11-amino undecanoic acid or 12-amino lauric acid or lauryl lactam; and preferably said polymeric matrix comprises units derived from the monomers: a) terephthalic acid, b1) 1,10decamethylene diamine, b2) 1,6-hexamethylene diamine and c) 11-amino undecanoic acid or said polymeric matrix comprises units derived from the monomers: a) terephthalic acid, b1) 1,10-decamethylene diamine, b2) 1,6hexamethylene diamine and c) 12-amino undecanoic acid. 19. The method of claim 16 or 17, wherein b1) is 1,10-decamethylene diamine and b2) is selected from 2-methyl pentamethylene diamine m-xylylene diamine or 1,3-bis (aminomethyl) cyclohexyl or 1,4-bis (aminomethyl) cyclohexyl and a) is terephthalic acid. 20. Method according to one of claims 16 to 19, in which the molar ratio of units derived from monomers b1 / (b1 + b2) varies from 55 to 75% and the molar ratio of units derived from monomers b2 / ( b1 + b2) varies from 25 to 45%. 21. Method according to one of claims 1 to 20, in which said reactive composition further comprises at least one nanofiller of carbonic origin chosen from: carbon black, graphenes, carbon nanofibrils and carbon nanotubes and / or an additive. 22. Method according to one of claims 1 to 21, wherein said reinforcing fibers are selected from mineral fibers, preferably glass, carbon or basalt, in particular glass or carbon, or from synthetic fibers , preferably aramid or polyaryl ether ketone fibers, or from mixtures thereof; and / or in which the reinforcing fibers have a L / D ratio greater than 1000, preferably greater than 2000, L being the average length of the fibers and D being their average diameter. 23. Method according to one of claims 1 to 22, wherein the 5 piece of composite material is a structural piece. 24. The method of claim 23, wherein the part is a road, rail, maritime, aeronautical or aerospace vehicle part, or a building part, or a reinforcement part. 10 shield or panel protecting against the impact of projectiles.