FR3045061A1 - REACTIVE COMPOSITIONS BASED ON AMINE POLYAMIDE SEMI-CRYSTALLINE PREPOLYMER AND UNSATURATED LENGTH FOR THERMOPLASTIC COMPOSITE MATERIALS - Google Patents

Abstract

The present invention relates to a reactive precursor composition of a thermoplastic composite material comprising reinforcing fibers and a matrix based on a semi-crystalline polyamide thermoplastic polymer impregnating said fibers, said composition comprising a1) at least one semicrystalline amine polyamide prepolymer (carrier of -NH2) of said thermoplastic polymer of the matrix and a2) a chain extender, non-polymeric and bearing a cyclic carboxylic anhydride group, preferably carried by an aromatic ring, having as a substituent a group comprising ethylenic or acetylenic unsaturation, said carboxylic anhydride group which may be in acid, ester, amide or imide form with a2) being present at a level corresponding to a molar ratio a2) / (-NH2) of less than 0.36 and said thermoplastic polymer of the matrix being the product of the polymerization reaction by elongation of a1) by a2). The invention also covers the composite material, thermoplastic polymer, the reactive composition based on a1) and a2) without fibers, a process for manufacturing a composite material and a mechanical or structural part obtained from the composition according to the invention. 'invention.

Description

The present invention relates to precursor reactive compositions of thermoplastic composite materials having a semi-crystalline polyamide thermoplastic polymer matrix impregnating reinforcing fibers with said reactive composition being based on a semicrystalline polyamide amine prepolymer and a specific extender which is a cyclic, preferably aromatic, cyclic carboxylic anhydride derivative substituted by a group comprising unsaturation, in particular acetylenic unsaturation, with a specific molar level of said elongator with respect to said prepolymer which allows, by a controlled reaction kinetics, a more effective impregnation with respect to reactive compositions already known from the state of the art. The invention also relates, in addition to said reactive composition, to said composite material, the semi-crystalline polyamide polymer resulting from the stretching reaction of said semi-crystalline polyamide amine prepolymer by said extender, the precursor reactive composition of said polymer, a process of manufacturing said composite material and in particular mechanical or structural parts, the use of said composition for composite materials and a mechanical part or structure obtained using said composition.

Composite materials and, more particularly, composite materials comprising reinforcing fibers impregnated with a polymer matrix are increasingly used in many technical fields, in particular in aeronautical, aerospace, wind turbine and automotive applications. , railway, marine. These applications require mainly high mechanical performance composites, especially at high operating temperatures and with weight-reduced structural parts compared to equivalent metallic and recyclable parts.

The composites, with a matrix based on thermosetting polymers, despite their ease of use and easy impregnation of the reinforcing fibers, have the drawbacks of the difficulty of recycling the thermosetting materials, the problem of dimensional stability related to the volume shrinkage after molding and crosslinking. and the toxicity of some monomeric components used as styrene.

One of the advantages of thermoplastic polymers as a matrix of a composite material is the fact that they are easily recyclable and in particular in the case of polyamides, lighter than thermosetting polymers. They offer new perspectives in the field of composites as a polymer matrix. However, the processes for manufacturing thermoplastic matrix composites are more restrictive than those using thermosets and the quality of the composite manufactured is not always optimal. The essential limiting factor for the implementation of a thermoplastic composite is the viscosity of the thermoplastic polymer which will be used as a matrix, impregnating the fibrous substrate, also called fibrous reinforcement. Indeed, even in the molten state, this viscosity remains high and thus makes. Impregnation of the fibrous substrate more difficult than a liquid resin, such as for example a thermosetting resin based on unsaturated polyester or vinyl ester.

Thus, the polymer matrix must first allow good impregnation of the reinforcing fibers in order to allow the transmission to the reinforcing fibers of the mechanical stresses to which the composite material is subjected, and thus a more efficient response of said composite material to the mechanical stress. Next, the coating of said reinforcing fibers with this matrix must provide chemical protection to these fibers. In particular, for a thermoplastic matrix composite to have good mechanical properties at the end use, especially in terms of impact resistance, it is necessary that the molecular weight of the thermoplastic polymer of the matrix is as high as possible. On the other hand, this high mass characteristic is reflected, during the manufacture of the composite, by a high melt viscosity of said thermoplastic polymer matrix. This viscosity poses serious difficulties to achieve proper impregnation of the fibers. As a consequence, the thermoplastic composite obtained may have impregnation defects with the creation of microvoids which are capable of causing mechanical deficiencies, in particular delamination of the fibers and embrittlement of the final thermoplastic composite material.

To improve the impregnation of the reinforcing fibers in the case of a thermoplastic composite material, reactive precursor compositions of the composite material based on a reactive prepolymer and a chain extender coreactive between them have been proposed. WO 2013/060976 describes in particular a process for preparing a thermoplastic composite material using, as precursor of the thermoplastic polymer matrix, a reactive composition of a prepolymer and a chain extender carrying coreactive functions, for the impregnation of said reinforcing fibers. The disadvantage of such a solution is the difficulty of controlling the kinetics of the reaction during the impregnation of said fibrous reinforcement with said melt precursor composition, which leads to an increase in the viscosity during the impregnation and a difficulty to have a perfect impregnation of the reinforcing fibers thereby. WO 2014/064375 describes specific compositions of semi-crystalline polyamide as a polyamide matrix for impregnating a fibrous reinforcement, said polyamide matrix being obtained from a reactive precursor composition used for impregnating said fibrous reinforcement, said reactive composition precursor comprising polyamide prepolymers or a polyamide prepolymer and a chain extender. However, the reaction kinetics of the reactive components of said reactive composition can not be satisfactorily controlled to avoid or limit the reaction during the impregnation step, thus leading to impregnation of the reinforcing fibers which is not sufficient. compared to the expected mechanical performance. US 2011306718 discloses a process for pultrusion of low Tg reactive aliphatic polyamides associated with chain extenders of polymeric structure carrying several anhydride or epoxide functions. This document does not describe any non-polymeric extender and especially no unsaturated extender. WO 2010/036170 describes polyamides terminated by acetylenic groups for crosslinkable polyamides which are no longer thermoplastic after reaction of the acetylenic groups. WO 2010/036175 discloses crosslinked molded articles from acetylenic polyamides.

None of the cited documents describe or suggest the reactive compositions of the present invention for thermoplastic composites.

The present invention is directed to specific precursor reactive compositions for thermoplastic composite materials and the resultant composite materials, with said reactive compositions allowing both a control of the polymerization kinetics at the time of the impregnation stage in the state. melting of the reinforcing fibers to allow the best impregnation of said fibers and finally, after polymerization, a thermoplastic polymer of sufficiently high molecular mass to give satisfactory mechanical performance compared to the requirements of various targeted applications. More particularly, the control of the polymerization kinetics initially and in particular during the melt mixing of the prepolymer and elongate reactive components prior to the impregnation of the reinforcing fibers, allows, as an option, the granulation of said mixture and its reuse (by reheating of the granules) in the molten state without any significant change in the viscosity, neither during the reheating nor during the impregnation step of the reinforcing fibers, the actual polymerization taking place only at longer times after impregnation at a given temperature or by increasing the temperature after effective impregnation of the reinforcing fibers. In fact, the specific reactive compositions of the present invention allow a latency time with no significant polymerization occurring during this time, thus permitting an improvement in the impregnation of the reinforcing fibers with respect to similar reactive compositions of the present invention. state of the art.

Indeed, at high temperature, whether during the mixing of the components or during the impregnation of the reinforcing fibers, the reaction kinetics for the known reactive compositions of the state of the art are often very fast and it is difficult. to impregnate the reinforcing fiber fabric correctly, even starting from very fluid products at the beginning. In addition, the increase in molecular weight of the final polymer must be sufficient to obtain good mechanical properties for the final material.

Thus, in WO 2014/064375 with the use as a polyamide chain extender of 1,3-phenylene-bis-oxazoline (PBO), the final viscosity obtained does not exceed 80 Pa.s, which does not exceed is not enough to obtain good properties of the matrix and therefore of the final composite. In addition, the kinetics of elongation is very fast, which leaves a window of time for the impregnation very reduced and does not allow for example a stop of the production.

The present invention is aimed in particular at composite materials with a semi-crystalline polyamide (PA) as thermoplastic matrix. The selection of a semicrystalline polyamide polymer as a matrix of the composite material of the invention with respect to the amorphous polyamides allows, in addition, significantly improved mechanical performance, especially at high temperatures, such as creep or fatigue resistance. In particular, for a melting point of at least 200 ° C, preferably at least 220 ° C, gives an additional advantage in the automobile which is the compatibility of such a choice with cataphoresis treatments, which that does not allow an amorphous PA type structure. More particularly, a glass transition temperature Tg of at least 80.degree. C. and preferably at least 90.degree. C. is sought to ensure good mechanical properties for the composite throughout the entire operating temperature range, for example up to at 90 ° C for wind turbines, up to 100 ° C for cars and up to 120 ° C for aeronautics. Preferably, the melting point does not exceed 280 ° C for questions of ease of use of the composite at accessible temperatures without constraints of molding material to use (and associated heating system) and without energy consumption and risk thermal degradation by heating at temperatures higher than the melting temperature of said polyamide, which may affect the properties of the final thermoplastic matrix and the resulting composite.

A first subject of the invention relates to a precursor composition of composite material having a specific composition and comprising: a1) at least one amine prepolymer (carrier of -NH2: primary amine function) which is a semi-crystalline polyamide and, a2) at minus a non-polymeric specific extender carrying a cyclic carboxylic anhydride group, preferably carried by an aromatic ring, having as a substituent a group comprising ethylenic or acetylenic unsaturation, preferably acetylenic with said elongator being in default with respect to -NH 2 .

A second subject of the invention relates to a composite material obtained from a precursor reactive composition as defined according to the invention.

Also covered by the present invention is a semi-crystalline polyamide thermoplastic polymer obtained by the polymerization reaction by elongation of said semi-crystalline a1) polyamide prepolymer by said specific extender a2) according to the invention.

Another subject of the invention relates to a precursor reactive composition of said thermoplastic polymer and comprising said amine prepolymer and said extender.

Also part of the invention is a method of manufacturing a thermoplastic composite material, in particular a mechanical part or a structural part based on said material, which comprises at least one polymerization step of at least one precursor reactive composition of said thermoplastic composite material. The invention also relates to the use of a precursor reactive composition of the composite material for the manufacture of mechanical parts or structural parts made of composite material.

Finally, the invention also relates to a finished product which is a mechanical part or structure made of a thermoplastic composite material which results from the use of at least one precursor reactive composition of said composite material or of the reactive precursor composition of said thermoplastic polymer or of the use of said thermoplastic polymer as defined according to the invention.

Thus, the first subject of the invention concerns a precursor reactive composition of thermoplastic composite material, said material comprising reinforcing fibers (also called fibrous reinforcement) and a matrix based on semicrystalline thermoplastic polyamide polymer impregnating said fibers (said reinforcement fibrous), which composition comprises: a1) at least one amine prepolymer (carrier of -NH 2) semi-crystalline polyamide, prepolymer of said thermoplastic polyamide polymer of the matrix, in particular with at least 50% of the end groups of said prepolymer a1) being primary amine functions -NH2, and a2) at least one chain extender, non-polymeric and bearing a cyclic carboxylic anhydride group, preferably carried by an aromatic ring, having as a substituent a group comprising ethylenic or acetylenic unsaturation, preferably acetylenic, said carboxylic anhydride group being capable of being acid, ester, amide or imide form with said extender a2) being present at a level corresponding to a molar ratio a2) / (-NH2) less than 0.36, preferably ranging from 0.1 to 0.35, more preferably ranging from 0.15 to 0.35 and even more preferentially ranging from 0.15 to 0.31, and with said thermoplastic polymer of the matrix being the product of the polymerization reaction by elongation of said prepolymer a1) by said lengthening agent a2) .

An "elongation" polymerization reaction according to the present invention herein means an increase in the molecular weight of the amine prepolymer a1) by reaction with the extender a2). Said reaction by the choice of components a1) and a2) and their specific molar ratio leads to a thermoplastic final polymer which is not crosslinked.

Said semi-crystalline polyamide prepolymer a1) carries primary amine groups represented by -NH2. More particularly, said functionality of said prepolymer a1) of at least 50% of the end groups of said prepolymer a1) being primary amine functions -NH2 means that it is possible for a part complementary to the amine end groups to be acidic groups carboxylic acids or chain ends blocked without reactive group and in this case the average functionality in -NH2, that is to say the average number of -NH2 groups per prepolymer a1) can vary from 1 to 3 and preferably from 1 to to 2.

Said elongator a2) may be chosen from: anhydrides and anhydride derivatives in the acid form, ester, amide or imide of ethynyl o-phthalic, methyl ethynyl o-phthalic, phenyl ethynyl o-phthalic, naphthyl ethynyl o-phthalic, 4 - (o-phthaloyl ethynyl) o-phthalic or 4- (phenyl ethynyl ketone) o-phthalic acid, the last being called phenyl ethynyl trimellitic anhydride, acids or esters or amides of ethynyl iso-phthalic acid, methyl ethynyl isophthalic acid , phenyl ethynyl isophthalic, naphthyl ethynyl isophthalic, 4- (o-phthaloyl ethynyl) isophthalic, 4- (phenyl ethynyl ketone) isophthalic, ethynyl terephthalic, methyl ethynyl terephthalic, phenyl ethynyl terephthalic, naphthyl ethynyl terephthalic, 4- (o-phthaloyl ethynyl) ) terephthalic, ethynyl benzoic, methyl ethynyl benzoic, phenyl ethynyl benzoic, naphthyl ethynyl benzoic, 4- (o-phthaloyl ethynyl) benzoic.

Said extender a2) is chosen in particular from aromatic anhydride compounds, preferably o-phthalic, substituted in the 4-position of the aromatic ring by a substituent defined by a group R - (> C- (R ') x- with R being a C1-C2 alkyl or H or aryl, in particular phenyl or R is the residue of an aromatic carboxylic anhydride, preferably o-phthalic, bonded to the acetylenic triple bond by the carbon at the 4-position of the aromatic ring and x being equal at 0 or 1 and for x being equal to 1, R 'being a carbonyl group, More particularly, said extender a2) is chosen from o-phthalic aromatic anhydride compounds bearing in the 4-position a substituent group chosen from methyl ethynyl , phenyl ethynyl, 4- (o-phthaloyl) ethynyl, phenyl ethynyl ketone, the last corresponding to phenyl ethynyl trimellitic anhydride and preferably carriers in the 4-position of a substituent group chosen from methyl thynyl and phenyl ethynyl ketone, the latter corresponding to phenyl ethynyl trimellitic anhydride. According to a more particular option, said extender a2) is 4-methyl ethynyl o-phthalic anhydride with a molar ratio a2) / NH2 ranging from 0.1 to 0.30 and preferably from 0.15 to 0.29. According to another particular option, said extender is o-phthalic anhydride 4-phenyl ethynyl ketone also called phenyl ethynyl trimellitic anhydride, with a molar ratio a2) / NH2 ranging from 0.1 to 0.36 and preferably from 0, 15 to 0.36.

Said non-polymeric extender a2) has a molecular weight of less than 500, preferably less than 400.

The term "thermoplastic" in the case of the present invention means that the polymer resulting from the reaction of the prepolymer a1) and the extender a2) is essentially thermoplastic, which means that it contains less than 15% of its weight. preferably less than 10% of its weight and more preferably less than 5% of its weight and even more preferably 0% of its weight (to within 0.5% or within 1%) of crosslinked polymers which are insoluble or infusible .

The meaning of "non-polymeric" for said elongate a2) is that it does not have a repeating polymer unit structure.

A semi-crystalline polymer means that said polymer has a melting temperature Tf of its crystalline structure when heated and a crystallization temperature Tc when it is cooled after melting. As suitable examples of semicrystalline polyamide, the following may be mentioned: polyamides from: 8.T, 9.T, 10.T, 11.T, 12.T ,, 6.T / 9.T, 9.T /10.T, 9.T / 11.T, 9.T / 12.T, 9 / 6.T, 10 / 6.T, 11 / 6.T, 12 / 6.T, 10 / 9.T , 10 / 10.T, 10 / 11.T, 10 / 12.T, 11 / 9.T, 11 / 10.T, 11 / 11.T, 11 / 12.T, 12 / 9.T, 12 /10.T, 12 / 11.T, 12 / 12.T, 6.10 / 6.T, 6.12 / 6.T, 9.10 / 6.T, 9.12 / 6.T, 10.10 / 6.T, 10.12 / 6 T, 6.10 / 9.T, 6.12 / 9.T, 9.10 / 9.T, 9.12 / 9.T, 10.10 / 9.T 10.12 / 9.T, 6.10 / 10.T, 6.12 / 10.T, 9.10 / 10.T, 9.12 / 10.T, 10.10 / 10.T, 10.12 / 10.T, 6.10 / 12.T, 6.12 / 12.T, 9.10 / 12.T, 9.12 / 12.T, 10.10 / 12.T, 11 / 6.T / 9.T, 11 / 6.T / 10.T, 11 / 6.T / 11.T, 11 / 6.T / 12.T, 11 / 9.T / 10.T, 11 / 9.T / 11.T, 11 / 9.T / 12.T, 11 / 10.T / 11.T, 11 / 10.T / 12.T, 11 / 11.T / 12.T, 6.T / 10.T, 6.T / 11.T, 6.T / 12.T, 10.T / 11.T, 10.T / 12.T, 11.T / 12. T, 12 / 6.T / 10.T, 12 / 6.T / 11.T, 12 / 6.T / 12.T, 12 / 9.T / 10.T, 12 / 9.T / 11. T, 12 / 9.T / 12.T, 12 / 10.T / 11.T, 12 / 10.T / 12.T, 12 / 11.T / 12.T, Previous terpolymer polyamides with 12 / replaced by 9 /, 10 /, 6.10 /, 6.12 /, 10.10 /, 10.12 /, 9.10 / and 9.12 /.

According to a preferred option, said semi-crystalline polyamide polymer has a glass transition temperature Tg of at least 80 ° C, more preferably at least 90 ° C and a melting temperature Tf ranging from 200 ° C to 280 ° C preferably from 220 ° C to 280 ° C.

Tg is measured by DSC in two passes at 20 ° C / min according to ISO 11357-2: 2013.

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

Preferably, said prepolymer a1) has a number-average molecular mass Mn ranging from 500 to 10,000, preferably from 1,000 to 6,000 and even more preferably from 1,000 to 4,000. The Mn of the semicrystalline amine polyamide prepolymer a1) is calculated from from the titration (titration) of the terminal functions according to a potentiometric method (direct assay for NH2 and carboxylic acids) and from the theoretical functionality which is 2 (in terminal functions) for linear prepolymers prepared from bifunctional monomers alone. When bifunctional and / or monofunctional and / or trifunctional monomer mixtures are used, the so-called theoretical functionality used for this calculation is the average number function fn taking into account the functionality fi and the molar fraction n of the component (monomer ) i in said mixture, with fn = Σι n * fi.

The amine and carboxylic acid functions are determined by titration (titration) of the terminal functions, which is carried out according to a potentiometric method (direct assay for NH2 or COOH).

Regarding the preparation of said semicrystalline polyamide amine prepolymer, it can be prepared by polycondensation reaction between, for example, a diacid and a diamine with said excess diamine. In the case of a linear a1) prepolymer with 100% amine end groups -NH 2, ie for an average functionality of -NH 2 of 2, bifunctional components are used with a polycondensation reaction of one. diacid and a diamine with amine functions in excess of carboxylic acid functions. For 50% of the end groups being amine -NH 2, that is to say for a mean functionality in -NH 2 of 1 target, the stoichiometry of the amine and carboxylic acid functions is used. A monofunctional blocking agent, for example monoamine, may be used in stoichiometry with the coreactive function to chemically block one of the two ends of the chain. In the case where the prepolymer a1) is branched with a branch on the main chain and with 100% of the end groups being amine -NH 2, that is to say with a mean objective of 3 in -NH 2 in addition to the components bifunctional, is used a trifunctional component (triacid or triamine) in the necessary amount (1 per chain) and an excess of amine functions to have an average number of 3 primary amine groups (-NH2) per chain of prepolymer a1) amine, semi polyamide -cristallin.

More particularly and preferably, said semi-crystalline polyamide amine prepolymer has the same amide unit composition as said semi-crystalline polyamide thermoplastic polymer, that is to say that the matrix polymer of the composite material and said amide units are from: a) a diacid component which is 95 to 100%, preferably 100 mol% of terephthalic structure with 0 to 5 mol% of isophthalic diacid, preferably a) being 100% terephthalic diacid; b) a diamine component composed of: b1) from 55 to 85%, preferably from 55 to 80 mol% of a linear aliphatic diamine of Cg, Cio, Cn or C12 and b2) of from 15 to 45%, preferably from 20 to 45 mol% of a diamine different from b1), selected from: b21) a mono-methylated aliphatic diamine with methyl or ethyl substituent and having a chain length difference with respect to the associated diamine b1), at least two carbons , preferably said diamine b2) being 2-methyl pentamethylenediamine b22) m-xylylene diamine (mXD) or b23) a linear aliphatic C4 to C18 diamine when b1) is a C10-C12 linear aliphatic diamine and with b23 ) being a C10-C18 diamine when said diamine b1 is a C9 diamine, and c) optionally an amino acid or, as the case may be, the corresponding lactam, C6 to C12, preferably C6, Cn or C12, and more preferably in Cn, with c) representing not more than 30 mol% with respect to a) or with respect to b).

According to a more particular option of said reactive composition, the diamine according to b1) is 1,10-decamethylene diamine, the diamine according to b2) is chosen from MPMD or mXD and the diacid according to a) is terephthalic acid.

According to another particular option of said reactive composition, said polyamide comprises b1), b2) and c) and the molar ratio in% of c / (b1 + b2) varies from 5 to 30% and preferably from 10 to 30%.

According to another particular option of said composition, said polyamide has as diacid a) terephthalic acid, as diamine b1) 1,10-decamethylene diamine, as diamine b2) 1,6-hexamethylene diamine or MPMD or mXD and as amino acid or lactam c) 11-amino-undecanoic acid or 12-amino-lauric acid or lauryl lactam.

More particularly, said polyamide comprises an amino acid or a lactam according to c) selected from 11-amino-undecanoic acid or 12-amino lauric acid or lauryl lactam.

According to a particular and preferred option, said polyamide has as diacid a) terephthalic acid, as diamine b1) 1,10-decamethylene diamine, as diamine b2) 1,6-hexamethylene diamine and as amino acid c) amino -11 undecanoic acid.

According to another option, said polyamide has as diacid a) terephthalic acid, as diamine b1) 1,10-decamethylene diamine, as diamine b2) 1,6-hexamethylene diamine and as amino acid c) amino-12 undecanoic acid.

In said reactive composition according to the invention, preferably the molar rate of b1 / (b1 + b2) varies from 55 to 75% and the molar level of b2 / (b1 + b2) varies from 25 to 45%.

The precursor reactive composition of composite material according to the invention may comprise in addition (ie in addition to a1) and a2) and reinforcing fibers), at least one nanocharge of carbonic origin chosen from: carbon black, graphenes, carbon nanofibrils and carbon nanotubes, said nanoburden being added in previously dispersed form in at least one of the constituents (a1) or a2)), which is the most preferably fluid in a2).

As regards said reinforcing fibers, they are selected from synthetic fibers, in particular mineral and polymeric fibers or from natural fibers and in particular vegetable fibers. More particularly, said reinforcing fibers are long fibers, in particular of circular section with L / D> 1000, preferably> 2000 and more particularly selected from glass, carbon, ceramic, aramid fibers or their mixtures. . The reinforcing fibers or fibrous reinforcement may be an assembly of fibers, preferably of long fibers, that is to say having a form factor defined by the ratio of length (L) to diameter (D) of the fiber, which means that these fibers have a circular section with L / D greater than 1000, preferably greater than 2000. In this assembly, the fibers may be continuous, in the form of unidirectional (UD) or multidirectional (2D, 3D) reinforcement. In particular, they may be in the form of fabrics, webs, strips or braids and may also be cut, for example in the form of nonwovens (mats) or in the form of felts.

These reinforcing fibers may be chosen from: mineral fibers, these having high melting temperatures and greater than the polymerization and / or processing temperature, the polymer or polymer fibers having a melting point or at defect a glass transition temperature higher than the polymerization temperature, the natural fibers, in particular of vegetable origin or the fiber mixtures mentioned above.

As mineral fibers suitable for the invention, mention may be made of carbon fibers, silica fibers such as glass fibers, in particular of type E, R or S 2, boron fibers, ceramic fibers, in particular carbon fiber fibers. silicon, boron carbide fibers, boron carbonitride fibers, silicon nitride fibers, boron nitride fibers, basalt fibers; fibers or filaments based on metals and / or their alloys; the fibers of metal oxides, especially alumina (Al 2 O 3); metallized fibers such as metallized glass fibers and metallized carbon fibers or mixtures of the aforementioned fibers.

The polymer or polymer fibers may be chosen from: thermoplastic polymer fibers and more particularly chosen from: polyethylene terephthalate (PET), polybutylene terephthalate (PBT), high density polyolefins such as polyethylene (PE), polypropylene (PP) and the PET / PP copolymers, the polyamide fibers corresponding to one of the formulas: 6, 11, 12, 6, 10, 6, 12, 6.6, 4.6, the aramid fibers such as Kevlar® and aromatic polyamides such as those corresponding to one of the formulas: PPD.T, MPD.I, PAA and PPA, with PPD and MPD respectively being p- and m-phenylene diamine, PAA being polyarylamides and PPA being polyphthalamides, copolymer fibers polyamide blocks such as polyamide / polyether, polyarylether ketone fibers (PAEK) such as polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetherketoneetherketoneketone (PEKEKK).

The preferred reinforcing fibers are long fibers with a circular cross-section chosen from: carbon fibers, including metallized fibers, glass fibers, including metallized type E, R, S2, ceramic fibers, aramid fibers (such as Kevlar®) or aromatic polyamides, polyarylethersketone (PAEK) fibers, such as polyetheretherketone (PEEK), polyetherketoneketone (PEKK) fibers, polyetherketoneetherketoneketone (PEKEKK) fibers or mixtures thereof.

The fibers that are more particularly preferred are chosen from: glass fibers, carbon fibers, ceramic fibers and aramid fibers (such as Kevlar®) or their mixtures. These fibers have a circular section.

Said fibers may represent levels of 40 to 70% by volume and preferably 50 to 65% by volume of said composite material and therefore of said reactive composition as defined above according to the invention. The assembly of fibers can be random (matte), unidirectional (UD) or multidirectional (2D "3D or other). Its basis weight, that is to say its weight per square meter, can range from 100 to 1000 g / m 2, preferably from 200 to 700 g / m 2. The fibers may be in woven or non-woven form, particularly in the form of fabrics and reinforcing fabrics. They can in particular be assembled and linked in the form of a preform already having the shape of the final piece.

According to a preferred option of said reactive composition according to the invention, it is a molding composition for molding in an open mold or in a closed mold.

The precursor reactive composition of composite material according to the invention may comprise in addition (ie in addition to a1) and a2) and reinforcing fibers), at least one nanocharge of carbonic origin chosen from: carbon black, graphenes, carbon nanofibrils and carbon nanotubes, said nanoburden being added in previously dispersed form in at least one of the constituents (a1) or a2)), which is the most fluid, preferably in a2).

The precursor composite material precursor composition according to the invention may comprise in addition (ie in addition to a1) and a2) and reinforcing fibers at least one specific catalyst of the polymerization reaction between a1 ) and a2). Examples of such catalysts, without the list being exhaustive, are given in US Pat. No. 8,697,823 and said catalyst may for example be chosen from cycloaliphatic tertiary amines such as 1,4-diazabicyclo [2.2.2] octane (DABCO). heteroaryls such as 4-dimethylethylaminopyridine (DMAP) or imidazoles such as 1-methylimidazole, 2-methylimidazoles or 1,2-dimethylimidazole, nucleophilic organophosphor compounds, such as triphenylphosphine, tributylphosphine, trimethylphosphine and phenyldimethylphosphine. Compounds such as Lewis acids or non-nucleophilic strong bases such as amidines such as 8-diazabicyclo [5.4.0] undec-7-ene (DBU) or guanidines such as 1,5,7-Triazabicyclo [ 4.4.0] dec-5-ene (TBD) or phosphazenes, such as 2-tert-Butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine (BEMP) or t-BuP4 can also be used according to the invention. A second subject of the invention concerns a composite material which is obtained from a precursor reactive composition as defined above according to the invention. More particularly, said composite material comprises reinforcing fibers (called fibrous reinforcement) and a matrix based on a semi-crystalline polyamide thermoplastic polymer impregnating said fibers (said fibrous reinforcement), said thermoplastic polymer having a glass transition temperature T g of at least 80 ° C, preferably at least 90 ° C and a melt temperature of 200 to 280 ° C, preferably 220 to 280 ° C and obtained by elongation polymerization of a prepolymer a1) of chain a2) as defined above according to the invention.

Also part of the present invention is the semi-crystalline polyamide thermoplastic polymer, which is obtained by polyaddition reaction of a reactive composition limited to the prepolymer a1) and to the elongator a2) as defined above according to the invention.

Also part of the present invention is the precursor reactive composition of said semi-crystalline polyamide thermoplastic polymer as defined above, which comprises a prepolymer a1) and an extender a2) as defined above according to the invention. Another object of the invention relates to a method of manufacturing a thermoplastic composite material as defined above and, in particular, to a mechanical part or a structural part based on said material, of composition such that defined above according to the precursor reactive composition, which process comprises at least one polymerization step of at least one reactive composition as defined above according to the invention. More particularly, said process comprises the following steps: i) preparation of an impregnating reactive composition comprising the prepolymer a1) and the extender a2) by melt blending of the components, with the optional storage of said composition form of granules for subsequent use in the following step ii), ii) melt impregnation in an open or closed mold or mold of a fibrous reinforcement by a reactive impregnation composition as defined according to the step i) and optionally and as the case may be, by melt heating of said impregnating composition being in the form of granules, in order to obtain a fibrous reinforcement impregnated with said impregnating composition, iii) mass polymerization reaction in the molten state of said reactive impregnating composition, by heating said fibrous reinforcement impregnated with step ii), iv) carried out by closed or open mold molding or by another off-mold implementation system and simultaneously with step iii) of polymerization.

Optionally, said method may comprise a post-polymerization stage v) in the solid state after implementation, in particular in the case where the polymerization reaction is incomplete.

According to a particular and preferred option of said method, said implementation is carried out according to one of the methods RTM or c-RTM (compression RTM) or S-RIM (structural RIM) or injection-compression or pultrusion or infusion, in particular one of RTM or c-RTM method or pultrusion.

Another subject of the invention relates to the use of a reactive composition or of a semi-crystalline polyamide thermoplastic polymer or of a reactive composition precursor of said polymer as defined above according to the invention, for the manufacture of parts mechanical or structural parts of composite material as already defined above according to the invention. More particularly, said use relates to mechanical parts or structural parts in the automotive, railway, marine (marine), wind, photovoltaic, solar, including solar panels and solar power plant components, sports, aeronautics and space, road transport. (concerning trucks), building, civil engineering, signs and the field of recreation.

Finally, the invention also relates to a mechanical part or structure of thermoplastic composite material, which results from the use of at least one precursor reactive composition of said composite material, as already defined above or the use of a semi-crystalline thermoplastic polyamide polymer as defined above or the use of a precursor reactive composition of said polymer as defined above or which is obtained by a process as defined above according to the invention.

More particularly, said structural part is an automobile part, in particular post-processed by cataphoresis or a piece of wind turbine or a part for aeronautics or for space.

The following examples are presented to illustrate the invention and its performance and in no way limit its scope.

Experimental part Methods for determining the characteristics cited

The titration (titration) of the terminal functions is carried out according to a potentiometric method (direct assay for NH2 or COOH). The number-average molecular weight Mn of the prepolymer a1) is calculated from the titration (assay) of the terminal functions according to a potentiometric method (direct assay for NH 2 and COOH) and from the theoretical functionality which is 2 (in functions terminals) for linear prepolymers prepared from bifunctional monomers alone.

The molar masses by number (Mn) and by weight (Mw) of the final polymers were determined by steric exclusion chromatography according to the standards ISO 16014-1: 2012,16014-2: 2012 and 16014-3: 2012 using the following conditions: Device: Waters Alliance 2695 instrument

Solvent: hexafluoroisopropanol stabilized with 0.05 M potassium trifluoroacetate Flow rate: 1 ml / minute Column temperature: 40 ° C

Two columns in series: 1000 A PFG and 100 A PFG (PPS)

Sample concentration: 1 g / L (dissolution at room temperature for 24 h) Sample filtration using a syringe equipped with an ACRODISC PTFE filter, diameter 25 mm, porosity 0.2 μm

Injection volume: 100 μΐ Refractometric detection at 40 ° C with UV detection at 228 nm

Calibration by PMMA standards from 1,900,000 to 402 g.mol -1. Calibration curve modeled by a fifth degree polynomial.

The level of insolubles was determined by weighing after dissolution in hexafluoroisopropanol at a concentration of 1 g / l for 24 h at ambient temperature, followed by filtration using a syringe equipped with an ACRODISC PTFE filter. diameter 25 mm, porosity 0.2 μm.

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

The melting temperature Tf and the crystallization temperature Te are measured by DSC, according to the standard ISO 11357-3: 2013. The heating and cooling rate is 20 ° C / min. The enthalpy of melting of said matrix polymer is measured in Differential Scanning Calorimetry (DSC) after a second heat-up according to the ISO 11357-3: 2013 standard.

Preparation of functionalized oligomers

The following procedure is an example of a preparation method and is of course not limiting. It is representative of all the compositions according to the invention.

In a 14 liter autoclave reactor, 5 kg of the following raw materials are introduced: 500 g of water, the diamine or diamines, the amino acid (optionally), the terephthalic diacid, 35 g of sodium hypophosphite in solution, 0 , 1 g of WACKER AK1000 antifoam (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 stirring for 30 minutes under these conditions, the pressurized steam which has formed in the reactor is gradually relieved in 60 minutes, while progressively increasing the material temperature so that it is established at Tf + 10. ° C at atmospheric pressure. The oligomer (prepolymer) is then drained through the bottom valve, then cooled in a bucket of water, and then ground.

The nature and molar ratio of the pattern and molecular structure of the exemplified polyamide, as well as its main characteristics, are given in Table 1 below. t

* calculated according to indicated method

** determined by size exclusion chromatography in PMMA equivalent

Preparation of the polyamide polymer by chain extension with a2 alloy

Oligomer 1 above dried and ground is mixed in the solid state with 4- (methyl ethynyl) phthalic anhydride (ΜΕΡΑ, Μη = 186.2 g / mol), sold under the name Nexamite® A32. by the company Nexam Chemical or phenyl ethynyl-trimellitic anhydride (PETA, Mn = 276.3 g / mol), sold under the name Nexamite® A56 by the company Nexam Chemical, at different molar ratios a2) / NH2. The amounts are calculated so that the mass of mixture is equal to 12 g.

The mixture is introduced under a nitrogen sweep in a DSM mark micro-extruder (volume 15 mL) with corotative conical screws preheated to 280 ° C. under rotation of the screws at 100 rpm. The mixture is left under recirculation in the micro-extruder and the increase in viscosity is monitored by measuring the normal force.

After about 12 minutes, the contents of the micro-extruder are drained in the form of a rod. The air-cooled product is granulated and analyzed. The results of analyzes are reported in Table 2.

Preparation of the CE8 (comparative) counterexample by chain extension with a Y-AY allonizer based on 1,3-PBO, according to WO 2013/060976

Oligomer 2 above dried and milled is mixed with a stoichiometric amount of 1,3-phenylene-bis- (2-oxazoline) (1,3-PBO). The stoichiometric amount was determined with respect to the acid number determined by potentiometric assay. Quantities are calculated so that the mass of mixture is equal to 12g.

The mixture is introduced under a nitrogen sweep in a DSM mark micro-extruder (volume 15 mL) with corotative conical screws preheated to 280 ° C. under rotation of the screws at 100 rpm. The mixture is left under recirculation in the micro-extruder and the increase in viscosity is monitored by measuring the normal force. After about 3 minutes, a plateau is reached and the contents of the micro-extruder are drained in the form of a rod. The air-cooled product is granulated and analyzed. The result is reported in Table 2.

* determined by size exclusion chromatography in PMMA equivalent

The results obtained show that examples E1 to E4 according to the invention are fully soluble thermoplastic polymers. Their melting temperature is above 200 ° C in all cases and their glass transition temperature above 90 ° C. Comparative counterexamples CE1 and CE3 respectively with respect to E1-E2 and E3-E4 have a significant portion of insolubles and are therefore no longer thermoplastics according to the definition of the present invention.

The values of Mw (in PMMA equivalent) indicate that an increase in the molar mass has taken place and that it is greater than that obtained with the counterexample CE8 according to WO 2013/060976. The evolution of the normal force over time is shown in the graph of Figure 1. The initial time is taken at the end of the introduction of the reaction mixture and a zero correction is then performed for this time.

It is clear that the normal force (related to the viscosity) is much greater for the examples according to the invention, compared with CE8 according to WO 2013/060976.

In addition, the kinetics of viscosification is also slower for the examples according to the invention. Thus, the time required to reach a normal force of 125 N is much greater for the examples according to the invention, which widens the window of impregnation of the fiber reinforcement and which is a further advantage of the present invention.

Table 3

Claims (29)

1. reactive composition which is a precursor of thermoplastic composite material, which material comprises reinforcing fibers (said fibrous reinforcement) and a matrix based on semi-crystalline polyamide thermoplastic polymer impregnating said fibers (said fibrous reinforcement), characterized in that it comprises: a1) at least one semi-crystalline amine polyamide prepolymer (carrying -NH 2), which is prepolymer of said thermoplastic polyamide polymer of the matrix, in particular with at least 50% of the end groups of said prepolymer a1) being functions of primary amine -NH2 and, a2) at least one chain extender7 which is non-polymeric and carries a cyclic carboxylic anhydride group, preferably carried by an aromatic ring, having as a substituent a group which comprises an ethylenic or acetylenic unsaturation , preferably acetylenic, with said carboxylic anhydride group being acid, ester, amide or imide form, and with said extender a2) being present at a level which corresponds to a molar ratio a2) / (- NH2) less than 0.36, preferably ranging from 0.1 to 0.35 more preferably from 0.15 to 0.35 and even more preferably from 0.15 to 0.31 and in that said thermoplastic polyamide polymer of the matrix is the product of the polymerization reaction by extension of the prepolymer a1. ) with said extender a2). 2. Composition according to claim 1, characterized in that said semi-crystalline polyamide polymer has a glass transition temperature Tg of at least 80 ° C, more preferably at least 90 ° C and a melting temperature Tf ranging from 200 ° C to 280 ° C, preferably 220 ° C to 2806C. 3. Composition according to claim 1 or 2, characterized in that said elongator a2) is chosen from aromatic anhydride compounds, preferably o-phthalic, substituted at the 4-position of the aromatic ring by a substituent defined by a group RC = C- (R ') x-with R being a C 1 -C 2 alkyl or H or aryl, in particular phenyl or R is the residue of an aromatic carboxylic anhydride, preferably o-phthalic, bonded to the acetylenic triple bond by the carbon in position And x being 0 or 1 and for x being 1, R 'being a carbonyl group. 4. Composition according to one of claims 1 to 3, characterized in that said elongator a2) is selected from o-phthalic aromatic anhydride compounds bearing in the 4-position of a substituent group selected from methyl ethynyl, phenyl ethynyl, 4 o -phthaloyl) ethynyl, phenyl ethynyl ketone, also called phenyl ethynyl trimellitic anhydride and preferably carriers in the 4-position of a substituent group selected from methyl ethynyl and phenyl ethynyl ketone. 5. Composition according to one of claims 1 to 4, characterized in that said lengthener a2) has a molecular weight less than 500, preferably less than 400. 6. Composition according to one of claims 1 to 5, characterized in that said prepolymer a1) has a number average molecular weight Mn calculated from 500 to 10000, preferably from 1000 to 6000. 7. Composition according to one of claims 1 to 6, characterized in that said prepolymer a1) has the same amide unit composition as said semi-crystalline polyamide thermoplastic polymer and in that said amide units are derived from: a) a diacid component which is from 95 to 100%, preferably to 100 mol% of terephthalic structure with 0 to 5 mol% of isophthalic diacid, preferably a) being 100% terephthalic diacid, b) a diamine component compound of: b1) from 55 to 85%, preferably from 55 to 80 mol% of a C, Cio, Cn or C12 aliphatic linear diamine and b2) from 15 to 45%, preferably from 20 to 45% in moles of a diamine different from b1), selected from: b21) a monoamined aliphatic diamine with a methyl or ethyl substituent and having a chain length difference with respect to the associated diamine b1), of at least two carbons, of preferably said diamine b2) being 2-methyl pentamethylene diamine b22) m-xylylene diamine (mXD) or b23) a C4 to C18 linear aliphatic diamine when b1) is a linear C10 to C12 aliphatic diamine and b23) is a C10 to C18 diamine when said diamine b1) is a C9 diamine, and c) optionally, an amino acid or, as the case may be, the corresponding lactam, from C6 to C12, preferably from Οθ, Ch or Ci2 and more preferably from Cn, with c) representing not more than 30 mol% in relation to (a) or in relation to (b). 8. Composition according to Claim 7, characterized in that the diamine according to b1) is 1,10-decamethylene diamine, that the diamine b2) is chosen from MPMD or mXD and that the diacid according to a) is terephthalic acid. 9. Composition according to claim 7 or 8, characterized in that said polyamide comprises b1), b2) and c) and that the molar ratio in% of c / (b1 + b2) varies from 5 to 30% and preferably from 10 to 30%. 10. Composition according to one of claims 7 to 9, characterized in that said polyamide has as diacid a) terephthalic acid, as diamine b1) 1,10-decamethylene diamine, as diamine b2) 1,6- hexamethylenediamine or MPMD or mXD and as amino acid or lactam c) 11-amino undecanoic acid or 12-amino acid lauric or lauryl lactam. 11. Composition according to one of claims 7 to 10, characterized in that said polyamide comprises an amino acid or a lactam according to c) selected from 11-amino acid undecanoic or 12-amino lauric acid or lauryl lactam. 12. Composition according to one of Claims 7 to 11, characterized in that said polyamide has as diacid a) terephthalic acid, as diamine b1) la-1,10-decamethylene diamine, as diamine b2) 1.6 hexamethylene diamine and amino acid c) 11-amino undecanoic acid. 13. Composition according to one of claims 7 to 11, characterized in that said polyamide has as diacid a) terephthalic acid, as diamine b1) 1,10-decamethylene diamine; as diamine b2) 1,6-hexamethylene diamine and as amino acid c) 12-amino undecanoic acid. 14. Composition according to one of claims 7 to 13, characterized in that the molar rate of b1 / (b1 + b2) varies from 55 to 75% and that the molar rate of b27 (b1 + b2) varies from 25 to 45%. 15. Composition according to one of claims 1 to 14, characterized in that it comprises in addition at least one -nanocharge of carbonic origin selected from: carbon black, graphenes, carbon nanofibrils and carbon nanotubes, said nanoburden being added in previously dispersed form in at least one constituent a1) or a2) which is the most fluid. 16. Composition according to one of claims 1 to 15, characterized in that said reinforcing fibers are selected from synthetic fibers, in particular mineral and polymeric fibers or from natural fibers and in particular vegetable fibers. 17. Composition according to one of claims 1 to 16, characterized in that said reinforcing fibers are long fibers, in particular circular section with L / D> 1000, preferably> 2000 and more particularly selected from the fibers of glass, carbon, ceramic, aramid or their mixtures. 18. Composition according to one of claims 1 to 17, characterized in that it is a molding composition for molding in open mold or closed mold. 19. Composite material, characterized in that it comprises reinforcing fibers (said fibrous reinforcement) and a matrix based on semicrystalline thermoplastic polyamide polymer impregnating said fibers (said fibrous reinforcement) and that it is obtained from a precursor reactive composition as defined according to one of claims 1 to 18. 20. Composite material, characterized in that it comprises reinforcing fibers (said fibrous reinforcement) and a matrix based on semicrystalline thermoplastic polyamide polymer impregnating said fibers (said fibrous reinforcement), said thermoplastic polymer having a transition temperature vitreous Tg of at least 80 ° C, preferably at least 90 ° C and a melting temperature of from 200 to 280 ° C, preferably from 220 to 280 ° C and obtained by polymerization by elongation of a prepolymer a1) by a chain extender a2) as defined according to one of claims 1 to 14. 21. Semi-crystalline thermoplastic polyamide polymer, characterized in that it is obtained by polyaddition reaction of a reactive composition limited to the prepolymer at) and the extender a2) as defined according to one of claims 1 to 14. . 22. Precursor reactive composition of the thermoplastic polymer as defined in claim 21, characterized in that it comprises a prepolymer a1) and an extender a2) as defined according to one of claims 1 to 14. 23. A method of manufacturing a thermoplastic composite material as defined in one of claims 1 to 18 or as defined in claim 19 or 20, in particular of a mechanical part or a piece of structure based said composite material which has a composition as defined in one of claims 1 to 18, said process being characterized in that it comprises at least one step of polymerization of at least one reactive composition as defined according to one of Claims 1 to 18. 24. The method of claim 23, characterized in that it comprises the following steps: i) preparation of a reactive impregnating composition comprising the prepolymer a1) and the extender a2) by melt blending of the components with optional storage of said composition in granular form for later use in the following step ii), ii) melt impregnation in an open or closed mold or mold of a fibrous reinforcement by a reactive composition of impregnation as defined in step i) and optionally and according to the case, by melt heating of said impregnating composition being in the form of granules, in order to obtain a fibrous reinforcement impregnated with said composition of impregnation, iii) molten mass polymerization reaction of said reactive impregnating composition, by heating said fibrous reinforcement impregnated with step ii) , iv) implemented by closed or open mold molding or by another non-mold implementation system and simultaneously with the polymerization step iii). 25. The method of claim 23 or 24, characterized in that said implementation is carried out according to one of RTM or c-RTM (compressional RTM) or S-RIM (structural RIM) or injection-compression or pultrusion or infusion, especially one of RTM or c-RTM method or pultrusion. 26. Use of a reactive composition as defined according to one of claims 1 to 18 for the manufacture of mechanical parts or structural parts of composite material as defined in one of claims 1 to 18 or as defined according to claim 19 or 20. 27. Use according to claim 26, characterized in that said mechanical parts or structural parts are mechanical or structural parts in the automotive, railway, marine (maritime), wind, photovoltaic, solar, including solar panels and components solar power plants, sports, aeronautics and space, road transport (for trucks), building, civil engineering, signage and recreation. 28. Mechanical part or straetwe thermoplastic composite material, characterized in that it results from the use of at least one composition as defined in one of claims 1 to 18 or that it is obtained by a method as defined in one of claims 23 to 25. 29. Structural part according to claim 28, characterized in that it is a car part, in particular post-treated by cataphoresis or a piece of wind turbine or a part for aeronautics or space.