EP3131948A1

EP3131948A1 - Composition and method for composite material impregnated with semi-crystalline polyamide, obtained from a prepolymer and a chain extender

Info

Publication number: EP3131948A1
Application number: EP15725735.3A
Authority: EP
Inventors: Gilles Hochstetter; Thierry Briffaud; Mathieu Capelot
Original assignee: Arkema France SA
Current assignee: Arkema France SA
Priority date: 2014-04-15
Filing date: 2015-04-15
Publication date: 2017-02-22
Also published as: FR3019827B1; JP2017511419A; WO2015159020A1; US20170037199A1; KR20160147822A; FR3019827A1; CN106232676A

Abstract

The invention relates to a moulding composition, in particular for a thermoplastic composite material, including at least one semi-crystalline polyamide obtained from the addition polymerisation of: a) at least one polyamide prepolymer having n identical X functions selected among carboxy, amine and hydroxyl; and b) at least one non-polymer reactive extender having two identical Y functions which are reactive with said X functions, wherein n ranges from 1 to 3, said polyamide and prepolymer a) including 55-95 mol % of amide A units and 5-45 mol % of amide B units, wherein A corresponds to x.T in which x is a C₉-C₁₈ linear aliphatic diamine, and B corresponds to x'.T in which x' can be B1): a specific branched aliphatic diamine dependent on x, B2): MXD, or B3): a linear aliphatic diamine dependent on x, said polyamide having a glass transition temperature of at least 90 °C and a melting temperature no higher than 280 °C. The invention also relates to a method for manufacturing said composite material, to the use of the composition of the invention for composite material parts, and to said parts.

Description

COMPOSITION AND METHOD FOR COMPOSITE MATERIAL WITH SEMI-CRYSTALLINE POLYAMIDE IMPREGNATION FROM PREPOLYMER AND CHAIN LENGTH

The invention relates to a specific non-reactive molding composition, in particular for a thermoplastic composite material with a semi-crystalline polyamide (PA) matrix having a glass transition temperature Tg of at least 80 ° C. and preferably at least 80 ° C. 90 ° C and melting temperature Tf less than or equal to 280 ° C, this polymer having a specific structure and also a method of manufacturing said composite material in particular mechanical parts or structure based on said material, the use of the composition of the invention for parts of composite material and the resulting composite part and for applications in the fields of: automotive, rail, marine, road transport, wind, sports, aeronautics and space , building, signs and recreation.

EP 0261 020 describes the use of semi-crystalline reactive prepolymers based on PA 6, 11 and 12 for the manufacture of a thermoplastic composite by a pultrusion process. Prepolymers of aliphatic structure as described have low Tg and insufficient mechanical performance when hot.

EP 2,586,585 discloses a method of manufacturing a composite material with fiber reinforcement comprising impregnating said fibrous reinforcement with a reactive precursor composition of a thermoplastic polymer, said precursor composition comprising a reactive prepolymer P (X) n and an extender of chain carrying two Y functions reactive with the X functions of said prepolymer. However, no melt-mass impregnation with the final thermoplastic polymer thus obtained is disclosed, suggested, or any related benefit.

EP 550 314 describes, among its examples, (non-reactive) copolyamide compositions in search of melting temperatures above 250 ° C and limited Tg's with most of the examples cited having a Tg too low (<80 ° C) or too high Tf (> 300 ° C).

EP 1 988 13 discloses a molding composition based on a 10T / 6T copolyamide with:

40 to 95 mol% of 10T

5 to 40% of 6T.

In particular, polyamides having a high melting point and greater than 270 ° C. are used. The examples mentioned and Figure 1 teach us that the melting temperature of these compositions is at least about 280 ° C. WO 201 1/003973 describes compositions comprising from 50 to 95 mol% of a linear aliphatic diamine-based unit containing from 9 to 12 carbon atoms and terephthalic acid and from 5 to 50% of a unit-forming unit. terephthalic acid to a mixture of 2,2,4 and 2,4,4 trimethylhexanediamine.

US 201 1306718 discloses a method of pultrusion of low Tg reactive aliphatic polyamides associated with chain extenders of polymeric structure bearing several (and much greater than 2) functions of anhydrides or epoxides. This document does not describe any non-polymeric extender.

The drawbacks of the state of the art with the absence of a good compromise between mechanical performance and processability (ease of processing) at lower temperature with a shorter production cycle time are surmounted by the solution of the present invention which aims at compositions of semi-crystalline PA, allowing easier implementation at lower temperatures with a saving on the overall energy balance of the implementation method, a cycle time of shorter production and improved productivity by rapid crystallizability of said polyamide polymer and while maintaining a high level of mechanical performance of said final materials.

The specific choice of a semi-crystalline polyamide polymer, as a matrix of the composite material of the invention, has the advantage, compared to amorphous polyamides, of significantly improved mechanical performance, especially at high temperature, such as resistance to creep or cracking. tired. In addition, having a melting point above 200 ° C has the advantage in the automobile to be compatible with cataphoresis treatments, which does not allow an amorphous PA type structure. As for amorphous materials, a Tg of greater than or equal to 80.degree. C., preferably at least 90.degree. C., is required to ensure good mechanical properties for the composite over the entire operating temperature range, for example up to 80.degree. C, preferably at least 90 ° C for wind, up to 100 ° C for automobiles and up to 120 ° C for aeronautics. On the other hand, a melting point that is too high, in particular greater than 280 ° C., is, however, detrimental since it requires the use of the composite at higher temperatures with constraints of molding material to be used (and heating system associated) and energy overconsumption with in addition to the risk of thermal degradation by heating at temperatures higher than the melting temperature of said polyamide, resulting in the assignment of the properties of the final thermoplastic matrix and the composite resulting therefrom. The crystallinity of said polymer must be as high as possible but with a not too high melting point Tf (Tf <280 ° C. and more particularly <270 ° C.) to optimize the mechanical performances and the speed of the polymer. crystallization and / or the highest possible crystallization temperature, this to reduce the molding time before ejection of the molded composite part with a selective choice of the composition of said semi-crystalline polyamide. Therefore, the object of the present invention is the implementation of new specific compositions of thermoplastic composite, in particular based on semicrystalline polyamide, having a good compromise between high mechanical performances (mechanical strength), especially when hot, and easy implementation. This means that there is a goal of compositions that are easy to implement with lower processing and processing temperatures than those for other compositions of the state of the art, with an overall energy balance of more favorable implementation, shorter cycle time and higher productivity. More particularly, the polyamide polymer matrix, while having a high Tg and a limited Tf as defined, with an easy implementation of said composite, must also have a high crystallization rate, characterized firstly by a difference between the melting temperature. and crystallization Tf-Tc not exceeding 50 ° C, preferably not exceeding 40 ° C and more preferably not exceeding 30 ° C. More preferably, this difference Tf-Tc does not exceed 30 ° C, unless Tf-Tg is <150 ° C, in which case (Tf-Tg <150 ° C), the difference Tf-Tc can vary up to 50 ° C. The mechanical performance or mechanical strength of the composite can be evaluated by the variation of the mechanical module between the ambient temperature (23 ° C) and 100 ° C with a maintenance of at least 75% of the mechanical performances, in terms of module , compared to those at room temperature (23 ° C). Therefore, the object of the invention is to develop a polyamide composition meeting these needs. The specific polymer of the invention, having the characteristics indicated above, is derived from the polyaddition reaction of a polyamide prepolymer a) with a non-polymeric extender b). More particularly, this specific semicrystalline polyamide polymer, used according to the present invention for impregnation in the molten state of a fiber reinforcement for the preparation of a thermoplastic composite material, has the additional advantage of having an easy implementation with improved fluidity, that is to say a melt viscosity at the same temperature for the impregnation of said fibrous reinforcement lower than that of the same polyamide but without incorporation of said elongator b) ( only difference) and also with the advantage of initially having a high molecular mass Mn and precontrol prior to the step of impregnating said fibrous reinforcement without high viscosity.

The first subject of the invention relates to a specific semi-crystalline polyamide (PA) non-reactive molding composition for a thermoplastic composite material, said polyamide having a Tg of at least 80 ° C., preferably at least 90 ° C. C and a Tf of less than or equal to 280 ° C, preferably less than 280 ° C with said polymer semi-crystalline polyamide of said composition being a non-reactive polymer and resulting from a polyaddition reaction between a) at least one reactive polyamide prepolymer of said semi-crystalline polyamide, bearing n identical reactive functions X among amine, carboxy or hydroxyl, preferably carboxy or amine, with n ranging from 1 to 3, preferably from 1 to 2 and more particularly from 2 and b) at least one non-polymeric Y-A'-Y chain extender with Y identical functions and reactive with said functions X said prepolymer a), with Y preferably being selected from: oxazine, oxazoline, oxazolinone, imidazoline, epoxy, isocyanate, maleimide, with said semi-crystalline polyamide and prepolymer a) being of specific structure based on different specific units A and B , with C and / or D patterns

The invention also relates to a method of manufacturing a thermoplastic composite material by using said specific polymer of the invention to impregnate a fibrous reinforcement.

It finally concerns the use of said non-reactive molding composition or said polymer according to the invention contained in said composition, for the melt impregnation of a fiber reinforcement as a thermoplastic matrix of a composite material, for manufacturing mechanical parts or structural parts of said composite material.

Therefore, the first object of the invention relates to a non-reactive molding composition, in particular for a thermoplastic composite material, comprising at least one thermoplastic polymer and optionally reinforcing fibers, also hereinafter referred to as fibrous reinforcement and in this case, said at least one polymer capable of impregnating said fibers or said fibrous reinforcement and forming the thermoplastic matrix of said composite material, said composition being characterized by the fact that:

said at least one thermoplastic polymer is a semi-crystalline polyamide polymer with a glass transition temperature Tg of at least 80 ° C, preferably at least 90 ° C and a melting temperature Tf of not more than 280 ° C .; and a polyaddition polymer between a) at least one thermoplastic polyamide prepolymer, bearing n identical terminal reactive functions X, chosen from: -MIH2, -CO2H and -OH, preferably NH2 and -CO2H with n being from 1 to 3, preferably 1 to 2, more preferably 1 or 2, more particularly 2 and b) at least one Y-A'-Y chain extender, with A 'being a single bond linking the two Y functions or a hydrocarbon biradical, non-polymeric structure and carrying 2 identical Y terminal reactive functional groups, with said Y functions being reactive by polyaddition with at least one X function of said prepolymer a) and preferably with Y being chosen from oxazine, oxazoline, oxazolinone , imidazoline, epoxy, isocyanate, maleimide, cyclic carboxylic anhydride, aziridine and preferably oxazoline or oxazine and said elongator b) having a molecular weight of less than 500, more preferably a molecular weight of less than 400, and

with said thermoplastic polyamide polymer and its prepolymer a) comprising in their respective structures different amide units A and B and optionally amide units C and D, selected as follows:

A: is a majority amide unit present at a molar level ranging from 55 to 95%, preferably from 55 to 85%, more preferably from 55 to 80%, selected from the units xT, where x is a linear aliphatic diamine in Cg to C 1, preferably C 8, C 10, C n and C 12 and where T is terephthalic acid, B: is an amide unit other than A, which unit B is present at a molar ratio ranging from 5 to 45%, preferably from 15 to 45%, more preferably from 20 to 45%, as a function of the Tf of the polyamide based on unit A and said amide unit B is chosen from among the units x'.T where x 'is chosen from: o B1) a branched aliphatic diamine bearing a single branch (or branching) methyl or ethyl and having a main chain length different from at least two carbon atoms with respect to the main chain length of the diamine x of said associated A unit, preferably x 'being 2-methyl pentamethylene diamine (MPMD) or o B2) the m-xylylene diamine (MXD) or

B3) a C ₄ to C 18 linear aliphatic diamine when in the unit A, said diamine x is a C ₁ to C 18 linear aliphatic diamine and x 'is a C ₈ to C 18 diamine when in the unit A, said diamine x is a diamine in Cg or C10,

and preferably B being selected from x'.T, where x 'is MPMD according to B1) or MXD according to B2) or a linear aliphatic diamine as defined above according to B3) and more preferably x' is MPMD according to B1 ) or MXD according to B2) and even more preferably MXD according to B2),

C: optional amide unit other than A and B, chosen from amide units based on a cycloaliphatic and / or aromatic structure or based on x'T as defined above for B but with x 'different from x 'for pattern B,

D: optional amide unit other than A, B and C when C is present and selected from aliphatic amide units from:

Amino acids or lactams C6 to C12, preferably C6, C11 and C12 or mixtures thereof ^■ reacting a linear aliphatic diacid C6-Cis, preferably C6 to C12 and a linear aliphatic diamine C6-Cis, preferably C6 to C12, or mixtures thereof

and with the proviso that the sum of the molar levels of A + B + C + D is 100%.

The term "non-reactive" molding composition according to the invention means that said composition is the same as that of the matrix polymer (polyamide) of said composite because there is no reaction in this composition, which remains stable and non-evolutive in term of molecular weight during its heating for the impregnation of a fibrous reinforcement and the implementation of the composite material of the invention. The characteristics of the polyamide polymer in this composition are the same, with Tg and Tf of the polyamide polymer of the thermoplastic matrix of said composite. The number-average molecular weight Mn of said polymer (polyamide) of the thermoplastic matrix of said composite and therefore of the polymer of said molding composition is preferably in a range from 12000 to 40000, preferably from 12000 to 30000. These Mn values may correspond to inherent viscosities greater than or equal to 0.8. The polyamides according to the invention are non-reactive, either by the low rate of reactive residual functions present, in particular with a rate of said functions <120 meq / kg, or by the presence of the same type of terminal functions at the end of the chain and therefore non-reactive with each other, either by modifying and blocking said reactive functions by a monofunctional reactive component, for example for the amine functions by modification reaction with a monoacid or a monoisocyanate and for carboxy functions by reaction with a monoamine.

Said non-reactive molding composition comprises, in particular in addition to said at least one semicrystalline polyamide polymer as defined above, at least one fibrous reinforcement, this molding composition being more particularly a composition for a thermoplastic composite material. Said molding composition may also comprise, in addition to said polymer, conventional fillers and additives which are not reinforcing fibers. Such fillers may be chosen from mineral fillers such as carbonates, pigments and carbonaceous fillers. More particularly, said molding composition comprises carbonaceous fillers, in particular carbon black or carbon nanofillers, these nanofillers being preferably chosen from graphenes and / or carbon nanotubes and / or carbon nanofibrils or mixtures thereof. More particularly, said composition may comprise said at least one polymer, said fibrous reinforcement and said fillers, in particular said carbonaceous nanofillers. According to a particular option of said polyamide polymer, said amide unit C is present and partially replaces B at a molar level of up to 25% relative to said unit B. Said unit D may also be present and as a partial replacement of B to a molar level of up to 70% relative to said pattern B.

Still referring to said polymer, the difference Tf-Tc, between the melting temperature Tf and the crystallization temperature Te of said impregnating polymer which serves as a matrix, does not exceed 50 ° C., preferably does not exceed 40 ° C., more preferably does not exceed 30 ° C. The crystallinity of said polyamide polymer is characterized by the enthalpy of crystallization, measured in Differential Scanning Calorimetry (DSC) according to the ISO Standard 1357-3, which is preferably greater than 40 J / g and more preferably greater than 45 J / boy Wut. More particularly, said amide unit A is present with a molar level ranging from 55 to 80%, preferably from 55 to 75%, more preferably from 55 to 70% relative to all the units of said polymer.

A first preferred option for said pattern B corresponds to x'T with x 'chosen according to option B1), in particular with x' being MPMD. According to a second option, said pattern B corresponds to x'T with x 'chosen according to option B2), x' being the MXD. According to a third option, said unit B corresponds to a linear aliphatic diamine according to option B3).

According to a more particular option, the patterns A and B are selected as follows: for the pattern A being 9T, said pattern B is selected from: 10T, 11T, 12T, 13T, 14T, 15T, 16T, 17T and 18T, MPMD.T and MXD.T, preferably 1T, 12T, 13T, 14T,

15T, 16T, 17T and 18T, MPMD.T and MXD.T, more preferably MPMD.T or

MXD.T, with a molar rate of B ranging from 30 to 45%

for the pattern A being 10T, said pattern B is selected from: 9T, 11T, 12T, 13T, 14T, 15T, 16T, 17T and 18T, MPMD.T and MXD.T, preferably 12T, 13T, 14T, 15T, 16T, 17T and 18T, MPMD.T and MXD.T, more preferably MPMD.T or MXD.T, with a molar ratio of B ranging from 25 to 45%

for the pattern A being 1 1 T, said pattern B is selected from: 9T, 10T, 12T, 13T, 14T, 15T, 16T, 17T and 18T, MPMD.T and MXD.T, preferably 9T, 13T, 15T, 16T, 17T and 18T, MPMD.T and MXD.T, more preferably MPMD.T or MXD.T, with a molar ratio of B ranging from 20 to 45%

for the pattern A being 12T, said pattern B is selected from: 9T, 10T, 11T, 13T, 14T, 15T, 16T, 17T and 18T, MPMD.T and MXD.T, preferably 9T, 10T, 14T, 15T, 16T, 17T and 18T, MPMD.T and MXD.T, more preferably MPMD.T or MXD.T, with a molar ratio of B ranging from 20 to 45%.

For each choice of A with a corresponding choice of B as mentioned above, it is possible to define a particular option for the choice of said polymer. According to another particular option on the choice of said polymer, part of the pattern B which can be up to 70%, preferably less than 40 mol% relative to B, is replaced by a pattern C and / or D as already defined. above.

As defined above according to the invention, said polymer of said molding composition used as impregnating polymer of the fiber reinforcement for the manufacture of a thermoplastic composite material is a polyaddition polymer between at least one prepolymer a) reactive by functions X and at least one elongator b) reactive by Y functions, as already defined above.

Said reactive prepolymers a) preferably have a number-average molecular weight Mn ranging from 500 to 10,000 and preferably from 1,000 to 6,000.

With regard to said elongators b) of structure Υ-ΑΎ which, by polyaddition reaction with said polyamide prepolymer a), make it possible to obtain said semi-crystalline polyamide polymer used for the melt impregnation of said fibrous reinforcement, examples may be mentioned suitable for obtaining said polymer as follows with respect to said function Y.

With regard to said extenders b) suitable for obtaining said polymer used in the impregnation step i), examples of chain extenders with reactive functions Y oxazoline or oxazine, suitable for the implementation of the polymer, may be mentioned. used in the process of the invention, reference may be made to those described under references "A", "B", "C" and "D" on page 7 of the applicant's application EP 0 581 642 and their processes of preparation and their modes of reaction which are exposed there. "A" is bisoxazoline, "B" is bisoxazine, "C" is 1,3-phenylene bisoxazoline, and "D" is 1,4-phenylene bisoxazoline.

Examples of suitable Y-imidazoline reactive chain extenders are those described ("A" to "F") on pages 7 to 8 and Table 1 on page 10 in EP 0 739 924 of the Applicant and their preparation processes and their reaction modes which are exposed.

As examples of Y = oxazinone or oxazolinone reactive chain extender, reference may be made to those described under references "A" to "D" on pages 7 to 8 of Applicant's application EP 0 581 641 and their processes of preparation and their modes of reaction which are exposed to them.

Examples of groups Y oxazinones (ring with 6 atoms) and oxazolinones (ring with 5 atoms) are suitable Y groups derived from: benzoxazinone oxazinone or oxazolinone, with A 'being a simple covalent bond with for respective corresponding extenders being: bis (benzoxazinone), bisoxazinone and bisoxazolinone. A 'may also be a C1 to C12, preferably a C2 to C10, alkylene, but preferably A' is an arylene and more particularly it may be a phenylene (1, 2 or 1, 3 or 1, 4 substituted with Y ) or a naphthalene radical (disubstituted by Y) or phthaloyl (iso- or terephthaloyl) or A 'may be a cycloalkylene.

For Y functions such as oxazine (6-ring), oxazoline (5-ring) and imidazoline

(ring at 5), the radical A 'may be as described above with A' being a single covalent bond and with the respective corresponding extenders being: bisoxazine, bisoxazoline and bisimidazoline. A may also be a C1 to C14 alkylene, preferably a C2 to C10 alkylene. The radical A 'is preferably an arylene and more particularly it may be a phenylene (1, 2 or 1, 3 or 1, 4 substituted with Y) or a naphthalene radical (disubstituted by Y) or a phthaloyl (iso- or terephthaloyl) or A 'may be cycloalkylene.

The presence of a catalyst for the reaction between the prepolymer a) (P (X) n) and the Y-A'-Y extender at a level ranging from 0.001 to 2%, preferably from 0.01 to 0, 5% relative to the total weight of said two co-reactants can accelerate the (poly) addition reaction and thus shorten the duration of the polyaddition reaction to obtain said polymer. Such a catalyst may be chosen from: 4,4'-dimethylaminopyridine, p-toluenesulphonic acid, phosphoric acid, NaOH and optionally those described for polycondensation or transesterification as described in EP 0 425 341, page 9, lines 1 to 7.

More particularly, said elongator corresponds to Y selected from oxazinone, oxazolinone, oxazine, oxazoline or imidazoline, preferably oxazoline and A represents a single covalent bond between the two functions Y or alkylene - (Chbjm- with m ranging from 1 to 14 and preferably from 2 to 10 or A representing a cycloalkylene or substituted arylene alkyl or unsubstituted, in particular benzene arylenes, among phenylenes o-, m-, p- or naphthalenic arylenes, preferably A 'being a cycloalkylene or an arylene or A 'being a simple covalent bond between the two functions Y.

Said reactive prepolymers a) of the precursor composition for preparing said semi-crystalline polyamide polymer have a number average molecular weight Mn which can range from 500 to 10,000, preferably from 1,000 to 6,000.

The weight ratio of said elongator b) in said semicrystalline polyamide thermoplastic polymer may vary, in particular according to the molecular weight M n of said prepolymer a), from 1 to 20%, preferably from 5 to 20% by weight.

A chain of said polymer may comprise at least 2 chains of said prepolymer a) linked together by an elongator molecule b) and preferably the number of prepolymer chains a) per chain of said polymer may vary from 2 to 80 and more preferably from 2 to 50. The Mn of said polymer can vary from 12,000 to 40,000, preferably from 12,000 to 30,000.

According to a particularly preferred option, said prepolymer a) carries X carboxy with n = 2 (at ± 0.1) and said extension b) carries Y = oxazoline.

More particularly, said semi-crystalline thermoplastic polyamide polymer according to the invention has a repetitive unitary structure according to the following formula (I):

NH - C - R - C NH - R '-

I 8

o o

with R being identical to A 'as defined above according to the invention for said Y-A'-Y extender and chosen from a single bond or hydrocarbon chain which may be aliphatic or cycloaliphatic or optionally substituted aromatic,

R 'being an optionally substituted aliphatic or cycloaliphatic or aromatic hydrocarbon chain and whose shortest chain connecting the neighboring -O- and -NH- units has 2 or 3 carbon atoms,

P being the chain of said polyamide prepolymer a) carrying said X = carboxy functions.

Still with regard to said polymer of the invention, said preferred extender b) is chosen from: phenylene bis oxazolines, preferably 1,3-phenylene bis (2-oxazoline) and 1,4-phenylene bis (2- oxazoline).

The melt viscosity of said polymer at the impregnation temperature is preferably <200 Pa.s and more preferably less than 150 Pa.s.

Preferably, the impregnation temperature is in a range from Tf + 10 to Tf + 80 ° C, more preferably Tf +10 to Tf + 50 ° C, with Tf being the melting temperature of said polyamide polymer. .

According to a preferred option, said molding composition comprises a fibrous reinforcement with long fibers, in particular of circular section with L / D> 1000, preferably> 2000 and more particularly selected from glass, carbon and ceramic fibers. aramid or mixtures thereof.

The second subject of the invention relates to a method for manufacturing a thermoplastic composite material, in particular a mechanical part or a structural part based on at least one composition as defined above, said method comprising a step i) of melt impregnation of a fibrous reinforcement by a molding composition, as defined above but without said fibrous reinforcement or by at least one polymer as defined according to the invention, in an open mold or in a closed mold or outside mold and optionally followed by a step ii) of final implementation consecutive or separate from said step i).

In particular, said method may comprise simultaneously or deferred an implementation step ii) comprising molding and final shaping said preimpregnated fibrous reinforcement of step i) to form the final composite part in a mold or out of mold.

More particularly, said implementation according to step ii) can be carried out according to a RTM technique, injection-compression, in particular under reduced pressure, pultrusion or by infusion or by thermocompression of prepreg under reduced pressure also commonly called "tarpaulin technique under vacuum ". RTM stands for Resin Transfer Molding (Resin Transfer Molding).

The last subject of the invention concerns the use of a composition as defined above according to the invention but without said fibrous reinforcement or the use of a polymer as contained in said composition defined according to the invention for the melt impregnation of a fibrous reinforcement as a thermoplastic matrix of a composite material, for the manufacture of mechanical parts or structural parts of said composite material.

In particular, said mechanical parts or structural parts of said composite material relate to applications in the automotive, railway, marine or maritime, wind, photovoltaic, solar, including solar panels and solar power plant components, sports, aerospace, transportation truck, building, civil engineering, protection and recreation panels, electrical or electronics.

More particularly, three more preferred applications can be distinguished according to the use temperature of said composite material parts according to the invention: in wind power, with a Tg of said thermoplastic matrix polyamide of at least

80 ° C and preferably 90 ° C or

in the automobile, with a Tg of said polyamide of at least 100 ° C or

in aeronautics, with a Tg of said polyamide of at least 120 ° C.

This means that for a Tg of at least 100 ° C, there can be two possible applications: the automobile and the wind and if the Tg is at least 120 ° C in addition to the aeronautics as an application, you can also have the wind and the automobile.

The melt viscosity of the polymer is measured according to the reference manual of the manufacturer of the measuring apparatus used, which is a Physica MCR301 rheometer, under a nitrogen sweep at the given temperature under shear of 100s ^-1 , between two parallel planes with a diameter of 50 mm.

The Mn of the prepolymer or thermoplastic polymer is determined from the titration (assay) of the terminal functions X according to a potentiometric method (back-titration of a reagent in excess with respect to the OH terminal functions and direct assay for Nhb or carboxy) and from the theoretical functionality ncale (vs X) calculated from the material balance and the functionality of the reactants. It can also be measured by size exclusion chromatography in PMMA equivalents according to indication.

Measurement of intrinsic or inherent viscosity is performed in m-cresol. The method is well known to those skilled in the art. The ISO 937 standard is followed but the solvent is changed (use of m-cresol instead of sulfuric acid and the temperature is 20 ° C).

The glass transition temperature Tg of the thermoplastic polymers used is measured using a differential scanning calorimeter (DSC) after a ^2nd pass in heaters, according to ISO 1 1357-2. The heating and cooling rate is 20 ° C / min.

The melting point Tf and the crystallization temperature Tc is measured by DSC, after a ^1st heater, according to ISO 1 1357-3. The heating and cooling rate is 20 ° C / min.

The enthalpy of crystallization of said matrix polymer is measured in Differential Scanning Calorimetry (DSC) according to the standard ISO 1,1357-3.

The following examples are presented as an illustration of the invention and its performance and in no way limit its scope.

A-1 Preparation of the reactive prepolymer P (X) n

In a 14 liter autoclave reactor, 5 kg of the following raw materials are introduced:

- 500 g of water,

Amines: MXD (m-xylylene-diamine) and diamine decane (proportion see below)

Diacid: T (terephthalic)

35 g of sodium hypophosphite in solution,

0.1 g of WACKER AK1000 antifoam (company Wacker Silicones).

The nature and molar ratios of the molecular patterns and structures of the reactive prepolymer polyamides (by referenced assay) are given below. 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 gradually increasing the material temperature so that it is established at a minimum of 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 characteristics of the prepolymer obtained are presented below:

Structure (mol% of the units): MXD.T / 10.T (41, 2 / 58.8)

- function X: carboxy

meq / kg of X: 621

Mn (potentiometry): 3221

Tg: 19.4 ° C

Tf / Tc: 270.3 ° C / 240.8 ° C

- H (ΔΗ) delta: 50.1 J / g

A-2 Preparation of the Polyamide Polymer According to the Invention by Chain Elongation with a Y-A'-Y Type Extender

10 g of the prepolymer presented above dried and ground are mixed with a stoichiometric amount of 1,3-phenylene-bis (2-oxazoline) (PBO).

The mixture is introduced under nitrogen flushing in a DSM brand micro-extruder (volume 15 mL) co-rotating conical screw preheated to 280 ° C, under rotation of the screws at 100 r / min. The mixture is left under recirculation in the micro-extruder and the increase in viscosity is monitored by measuring the normal force. After about 2 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.

The characteristics of said polymer are as follows:

Tg: 135 ° C

Tf / Tc: 273 ° C / 230.5 ° C

- Delta H (ΔΗ): 36 J / g

Mn (SEC): 9900 g / mol PMMA equivalent

A-3 Comparative PA Preparation Without Extender

Comparative polyamides lacking PA chain extenders are synthesized according to a protocol similar to the reactive prepolymers P (X) n. The Mn is adjusted according to a controlled excess of diacid, according to the method well known to those skilled in the art. The Amino and diacid components are the same with the same proportions of the components except adjusting the ratio of acid / amine functions to have the desired Mn comparable to that of the polymer obtained with the extender described above.

The characteristics obtained are presented below:

Structure (mol% of the units): MXD.T / 10.T (41, 2 / 58.8)

Tg: 130.7 ° C

Tf / Tc: 279.2 ° C / 241.4 ° C

Delta H (ΔΗ): 43.6J / g

Mn (SEC): 10000 g / mol PMMA equivalent

A-4 Comparison of Melt Viscosities Between PA with Lengthening Device According to the Invention and Comparative PA Without Extender

This viscosity was measured at 2 reference temperatures: 280 ° C. and 300 ° C. for the two polyamides compared, with the results presented in the table below showing that as the temperature increases, above the melting temperature, the viscosity of the polyamide according to the invention decreases much more significantly than that of the comparative polyamide without said chain extender.

This greater fluidity of the polyamide according to the invention is an advantage of the invention compared to the state of the art in the context of a more effective impregnation of a fiber reinforcement for the preparation of thermoplastic composite materials with fibrous reinforcement. having said polymer as a thermoplastic matrix, with increased mechanical performance of said materials.

Claims

1. Non-reactive molding composition, in particular for a thermoplastic composite material, comprising at least one thermoplastic polymer and optionally reinforcing fibers or fibrous reinforcement and in this case, said at least one polymer capable of impregnating said fibers (or said fibrous reinforcement) and forming the thermoplastic matrix of said composite material, said composition being characterized:

in that said at least one thermoplastic polymer is a semi-crystalline polyamide polymer with a glass transition temperature Tg of at least 80 ° C, preferably at least 90 ° C and a melting temperature Tf of less than or equal to 280 ° C and that it is a polyaddition polymer between a) at least one thermoplastic polyamide prepolymer, bearing n identical terminal reactive functions X, chosen from: -Nhb, -CO2H and -OH, preferably N H2 and -CO2H with n being 1 to 3, preferably 1 to 2, more preferably 1 or 2, more particularly 2 and b) at least one Y-A'-Y chain extender, with A 'being a single bond linking the two functions Y or a hydrocarbon-based biradical, of non-polymeric structure and carrying 2 identical terminal reactive functions Y, reactive by polyaddition with at least one function X of said prepolymer a), preferably with Y being chosen from oxazine, oxazoline, oxazolinone, imidazoline, ep oxy, isocyanate, maleimide, cyclic carboxylic anhydride, aziridine, preferably oxazoline and oxazine, and said extender b) having a molecular weight of less than 500, more preferably a molecular weight of less than 400, and

in that said thermoplastic polyamide polymer and its prepolymer a) comprise in their respective structures amide units A and B different and optionally amide units C and D, selected as follows:

A: is a majority amide unit present at a molar level ranging from 55 to 95%, preferably from 55 to 85%, more preferably from 55 to 80%, selected from the units xT, where x is a linear aliphatic diamine in C9 at C18, preferably C9, C10, C11 and C12 and where T is terephthalic acid, B: is an amide unit other than A, which unit B is present at a molar level ranging from 5 to 45%, preferably from 15 to 45%, more preferably from 20 to 45%, as a function of the Tf of the polyamide based on unit A and said amide unit B is chosen from among the units x'.T where x 'is chosen from: o B1) a branched aliphatic diamine bearing a single branch (or branching) methyl or ethyl and having a chain length different from at least two carbon atoms with respect to the main chain length of the diamine x of said associated A unit, preferably x 'being 2-methyl pentamethylene diamine (MPMD) or o B2) m-xylylene diamine (MXD) or

B3) a C ₄ -C 18 linear aliphatic diamine when in the unit A, said diamine x is a C ₁ -C 18 linear aliphatic diamine and x 'is a C 8 -C 18 diamine when in the unit A, said diamine x is a diamine in Cg or C10,

Amino acids or lactams C6 to C12, preferably C6, C11 and C12 or mixtures thereof

The reaction of a C 6 to C 18 linear aliphatic diacid, preferably

C6 to C12 and a linear aliphatic diamine C6 to C18, preferably C6 to C12 or mixtures thereof

and with the proviso that the sum of the molar levels of A + B + C + D is 100%.

2. Composition according to claim 1, characterized in that said amide unit C is present and partially replaces B at a molar level of up to 25% relative to said pattern B.

3. Composition according to one of claims 1 to 2, characterized in that said pattern D is present and partially replacing B at a molar rate of up to 70% relative to said pattern B.

4. Composition according to one of claims 1 to 3, characterized in that the difference Tf-Tc, between the melting temperature Tf and the crystallization temperature Te of said matrix polymer, does not exceed 50 ° C, preferably does not exceed not 40 ° C, more preferably does not exceed 30 ° C.

5. Composition according to one of claims 1 to 4, characterized in that the enthalpy of crystallization, measured in Differential Scanning Calorimetry (DSC) according to ISO Standard 1 1357-3, is greater than 40 J / g, preferably greater than 45 J / g.

6. Composition according to one of claims 1 to 5, characterized in that said amide unit A is present with a molar level ranging from 55 to 80%, preferably from 55 to 75%, more preferably from 55 to 70% by relative to all the units of said polymer.

7. Composition according to one of claims 1 to 6, characterized in that said pattern B corresponds to x'T with x 'selected according to option B1), in particular with x' being MPMD.

8. Composition according to one of claims 1 to 6, characterized in that said pattern B corresponds to x'T with x 'selected according to option B2), x' being the MXD.

9. Composition according to one of claims 1 to 6, characterized in that said pattern B corresponds to a linear aliphatic diamine according to option B3).

10. Composition according to one of claims 1 to 6, characterized in that the patterns A and B are selected as follows:

for the pattern A being 9T, said pattern B is selected from: 10T, 11T, 12T, 13T, 14T, 15T, 16T, 17T and 18T, MPMD.T and MXD.T, preferably 1T, 12T, 13T , 14T, 15T, 16T, 17T and 18T, MPMD.T and MXD.T, more preferably MPMD.T or MXD.T, with a molar ratio of B ranging from 30 to 45%

for the pattern A being 1 1 T, said pattern B is selected from: 9T, 10T, 12T, 13T, 14T, 15T, 16T, 17T and 18T, MPMD.T and MXD.T, preferably 9T, 13T, 15T , 16T, 17T and 18T, MPMD.T and MXD.T, more preferably MPMD.T or MXD.T, with a molar ratio of B ranging from 20 to 45%

for pattern A being 12T, said pattern B is selected from: 9T, 10T, 1T, 13T, 14T, 15T, 16T, 17T and 18T, MPMD.T and MXD.T, preferably 9T, 10T, 14T, 15T ,

16T, 17T and 18T, MPMD.T and MXD.T, more preferably MPMD.T or MXD.T, with a molar ratio of B ranging from 20 to 45%.

1 1. Composition according to Claim 10, characterized in that the pattern A is a 9T pattern and the pattern B is selected from: 10T, 11T, 12T, 13T, 14T, 15T, 16T, 17T and 18T, MPMD.T and MXD T, preferably 11T, 12T, 13T, 14T, 15T, 16T, 17T and 18T, MPMD.T and MXD.T, more preferably MPMD.T or MXD.T, with a molar ratio of B ranging from 30 at 45%.

12. Composition according to claim 10, characterized in that the pattern A is a pattern 10T and the pattern B is selected from: 9T, 11T, 12T, 13T, 14T, 15T, 16T, 17T and 18T, MPMD.T and MXD.T, preferably 12T, 13T, 14T, 15T, 16T, 17T and 18T, MPMD.T plus preferentially MPMD.T or MXD.T and MXD.T with a molar ratio of B ranging from 25 to 45%.

13. Composition according to claim 10, characterized in that the pattern A is a pattern 1 1 T and the pattern B is selected from: 9T, 10T, 12T, 13T, 14T, 15T, 16T, 17T and 18T, MPMD.T and MXD.T, preferably 9T, 13T, 15T, 16T, 17T and 18T, MPMD.T and MXD.T, more preferably MPMD.T or MXD.T, with a molar ratio of B ranging from 20 to 45%.

14. Composition according to claim 10, characterized in that the pattern A is a pattern 12T and the pattern B is selected from: 10T, 11T, 13T, 14T, 15T, 16T, 17T and 18T, MPMD.T and MXD T, preferably 9T, 10T, 14T, 15T, 16T, 17T and 18T, MPMD.T and MXD.T, more preferably MPMD.T or MXD.T, with a molar ratio of B ranging from 20 to 45%.

15. Composition according to one of claims 7 to 14, characterized in that part of the pattern B which is up to 70%, preferably less than 40 mol% relative to B, is replaced by a pattern C and / or D as defined according to one of claims 1 to 3.

16. Composition according to one of claims 1 to 15, characterized in that said reactive prepolymers a) have a number average molecular weight Mn ranging from 500 to 10,000, preferably from 1000 to 6000.

17. Composition according to one of claims 1 to 16, characterized in that the weight ratio of said elongator in said semi-crystalline polyamide thermoplastic polymer ranges from 1 to 20% by weight and preferably from 5 to 20% by weight.

18. Composition according to one of claims 1 to 17, characterized in that a chain of said polymer comprises at least 2 chains of said prepolymer a) linked together by an elongator molecule b), preferably the number of prepolymer chains a) by chain of said polymer ranging from 2 to 80 and more preferably from 2 to 50.

19. Composition according to one of claims 1 to 18, characterized in that said prepolymer a) carries X = carboxy and n = 2 (to ± 0.1) and said elongator carries Y = oxazoline.

20. Composition according to claim 19, characterized in that said semi-crystalline thermoplastic polyamide polymer has a repeating unitary structure according to the following formula (I):

- O - C - P - c - o - R '- NH - C - R - C - NH -R

8 I ί 8

o o o o

(I) with R being identical to A 'as defined according to claim 1 and selected from a single bond or hydrocarbon chain, which may be aliphatic or cycloaliphatic or optionally substituted aromatic,

21. Composition according to Claim 19 or 20, characterized in that the said lengthening agent is chosen from: phenylene bis oxazolines, preferably 1,3-phenylene bis (2-oxazoline) and 1,4-phenylene bis (2-oxazoline).

22. Composition according to one of claims 1 to 21, characterized in that it comprises a fibrous reinforcement with long fibers, in particular circular section with L / D> 1000, preferably> 2000 and more particularly selected from glass, carbon, ceramic, aramid fibers or mixtures thereof.

23. A method of manufacturing a thermoplastic composite material, in particular a mechanical part or a structural part based on at least one composition as defined according to one of claims 1 to 22, characterized in that it comprises a step i) of melt impregnation of a fibrous reinforcement with a molding composition, as defined according to one of claims 1 to 21 but without said fibrous reinforcement or by at least one polymer as defined according to one of claims 1 to 21 in an open mold or in a mold closed or out of mold and possibly followed by a step ii) final implementation consecutive or separate said step i).

24. The method of claim 23, characterized in that it comprises simultaneously or deferred a step ii) of implementation comprising molding and final shaping said preimpregnated fibrous reinforcement of step i) to form the composite part final in a mold or out of mold.

25. The method of claim 24, characterized in that said implementation according to step ii) is carried out according to a RTM technique, injection-compression, pultrusion or by infusion, thermocompression of prepreg under reduced pressure.

26. Use of a composition as defined in one of claims 1 to 21 without said fibrous reinforcement or use of a polymer as contained in said composition for the melt impregnation of a reinforcement fiber as a thermoplastic matrix of a composite material, for the manufacture of mechanical parts or structural parts of said composite material.

27. Use according to claim 26, characterized in that said mechanical parts or structural parts of said composite material relate to applications in the automotive, railway, marine or maritime, wind, photovoltaic, solar, including solar panels and solar power plant components, sports, aeronautics and space, road transport relating to trucks, building, civil engineering, protective panels and recreation, electrical and electronics.

28. Use according to claim 27, characterized in that it relates to applications in the field of wind energy and the Tg of said polyamide is at least 80 ° C and preferably at least 90 ° C.

29. Use according to claim 27, characterized in that it relates to applications in the automotive field and the Tg of said polyamide is at least 100 ° C.

30. Use according to claim 27, characterized in that it relates to applications in the field of aeronautics and that the Tg of said polyamide is at least