EP3253822A1

EP3253822A1 - Polyamide composition with delayed combustibility

Info

Publication number: EP3253822A1
Application number: EP16705909.6A
Authority: EP
Inventors: Marc Audenaert; Philippe Blondel; Jean-Jacques Flat
Original assignee: Arkema France SA
Current assignee: Arkema France SA
Priority date: 2015-02-05
Filing date: 2016-02-05
Publication date: 2017-12-13
Also published as: FR3032445A1; US20180037718A1; CN107207782A; KR20170110655A; JP2018505942A; WO2016124766A1

Abstract

The invention relates to a composition comprising: at least one polyamide; at least one melamine derivative as a fire-retardant agent; optionally at least one polyol comprising at least four times the alcohol function; and optionally at least one reinforcement in the form of a fibre. The invention also relates to the method for producing said composition and to the use of same.

Description

COMBUSTIBILITY POLYAMIDE COMPOSITION

DELAYED

The present invention relates to a composition comprising at least one polyamide, at least one particular flame retardant, optionally at least one polyol and optionally at least one specific reinforcement, and a process for preparing said composition and uses of said composition.

The use of materials such as polyamides has grown considerably over the last ten years. These materials are often intended to replace parts initially made of metal, thus leading to a significant relief of the article thus modified. However, it has turned out that in certain fields these materials have been little exploited because of their excessive flammability.

For example, in the field of transport, and more specifically aviation, the standards required in terms of flammability are drastic. Airworthiness regulations require specific flammability tests. Indeed, it can not be tolerated within a device, such as a plane too easily flammable materials.

In addition, it is also sought in particular in the field of transport to lighten the structures as much as possible, even those already in the state of plastic materials. Indeed, it is sought to lighten the structures in order to reduce the fuel consumption costs and to limit the ecological footprint related to the consumption of these fuels.

Therefore, there is a real need to provide polyamide-based compositions having improved properties in terms of flammability, weight and ease of implementation.

In order to improve the flame retardant properties of plastic materials, a lot of research has been done.

Some have focused on the development of new additives: flame retardants to incorporate into the material. Thus, Non-halogenated and phosphorus-derived product lines are developed: phosphinates, but without actually producing satisfactory results.

This research led to the composition disclosed in EP 0 169 085. The latter discloses a specific association of flame retardant compounds: melanin cyanurate and a polyol.

The Applicant has continued his studies in this particular field and has found that the composition according to the invention leads to unexpected results in terms of retardation to combustion.

Other features, aspects, objects and advantages of the present invention will become more apparent upon reading the following description and examples.

The present invention is therefore firstly obj and a composition comprising:

at least one polyamide,

at least one melamine derivative as flame retardant,

optionally at least one polyol comprising at least four alcohol functions, and

optionally, at least one reinforcement in the form of fiber.

The invention also relates to a process for preparing such a composition.

The invention relates to a use of the composition, especially in the electrical, electronic and avionics fields.

The invention is finally obj and an article obtained from this composition.

Polyamide

In general, the polyamides used in the composition according to the invention are semi-crystalline or amorphous in particular obtained by anionic polycondensation and comprise at least two identical or distinct repeating units, these units being able to be formed from a dicarboxylic acid and a diamine; an amino acid; lactam or mixtures thereof.

The polyamide according to the invention may be a homopolyamide and comprise at least two identical repeating units obtained from an amino acid, obtained from a lactam, or corresponding to the formula (diamine Ca). (Cb diacid), where a represents the number of carbon atoms of the diamine and b represents the number of carbon atoms of the diacid, a and b each being between 4 and 36, as defined below.

The polyamide according to the invention may also be a copolyamide and comprise at least two distinct repeating units, these units being obtainable from an amino acid obtained from a lactam or having the formula (diamine Ca). (Cb diacid), with a representing the number of carbon atoms of the diamine and b representing the number of carbon atoms of the diacid, a and b each being between 4 and 36, as defined below.

The patterns (diamine in Ca). (Cb diacid) may be aliphatic and linear, cycloaliphatic or aromatic.

The polyamide according to the invention may comprise at least one amino acid chosen from 9-aminononanoic acid, 10-aminodecanoic acid, 12-amino-dodecanoic acid and 11-aminoundecanoic acid and its derivatives, especially N-heptyl-1-aminoundecanoic acid.

The polyamide according to the invention may comprise at least one lactam chosen from pyrrolidinone, piperidinone, capro lactam, enantho lactam, caprylolactam, pelargolactam, decano lactam, undecanolactam and laurolactam.

The polyamide according to the invention may comprise at least one unit corresponding to the formula (diamine Ca). (Diacid Cb), the unit (diamine Ca) is of formula H ₂ N- (CH ₂ ) a -NH ₂ , when the diamine is aliphatic and linear.

Preferentially, when the diamine in Ca is linear and aliphatic, it is chosen from butanediamine (a = 4), pentanediamine (a = 5), hexanediamine (a = 6), heptanediamine (a = 7), octanediamine (a = 8), nonanediamine (a = 9), decanediamine (a = 10), undecanediamine (a = 11), dodecanediamine (a = 12), tridecanediamine (a = 13), tetradecanediamine (a = 14), hexadecanediamine (a = 16), octadecanediamine (a = 18), o-ceradecene diamine (a = 18), eicosanediamine (a = 20), docosanediamine (a = 22) and diamines obtained from fatty acids.

When the diamine is cycloaliphatic, it is preferably chosen from those comprising two rings. They respond in particular to the following general formula:

in which

R 1, R ₂ , R ₃ and R ₄ represent identical or different groups chosen from a hydrogen atom or alkyl groups of 1 to 6 carbon atoms and X represents either a single bond or a divalent group consisting of:

of a linear or branched aliphatic chain comprising from 1 to 10 carbon atoms, optionally substituted by cycloaliphatic or aromatic groups of 6 to 8 carbon atoms,

a cycloaliphatic group of 6 to 12 carbon atoms.

More preferably, the cycloaliphatic diamine of the polyamide according to the invention is chosen from bis (3,5-dialkyl-4-aminocyclohexyl) methane, bis (3,5-dialkyl-4-aminocyclohexyl) ethane, bis (3, 5-dialkyl-4-aminocyclohexyl) propane, bis (3,5-dialkyl-4-aminocyclohexyl) butane, bis (3-methyl-4-aminocyclohexyl) methane (denoted BMACM, MACM or B), p-bis (amino cyclohexyl) methane (PACM) and isopropylidenedi (cyclohexylamine) (PACP).

A non-exhaustive list of these cycloaliphatic diamines is given in the publication "Cycloaliphatic Amines" (Encyclopaedia of Chemical Technology, Kirk-Othmer, 4th Edition (1992), pp. 386-405).

Preferably, when the diamine is alkylaromatic, it is chosen from 1, 3 -xylylene diamine, 1,4-xylylenediamine and their mixture.

Preferably, when the monomer (Cb diacid) is aliphatic and linear, it is chosen from succinic acid (b = 4), pentanedioic acid (b = 5) and adipic acid (b = 6). ), heptanedioic acid (b = 7), octanedioic acid (b = 8), azelaic acid (b = 9), sebacic acid (b = 10), undecanedioic acid (b = 11), ), dodecanedioic acid (b = 12), brassylic acid (b = 13), tetradecanedioic acid (b = 14), hexadecanedioic acid (b = 16) and octadecanoic acid (b = 1). 8), octadecenedioic acid (b = 18), eicosanedioic acid (b = 20), docosanedioic acid (b = 22) and fatty acid dimers containing 36 carbons.

Preferably, when the monomer (Cb diacid) is aromatic, it is chosen from terephthalic acid, denoted T and isophthalic acid, denoted I and naphthalene diacid.

The fatty acid dimers mentioned above are dimerized fatty acids obtained by oligomerization or polymerization of unsaturated long-chain hydrocarbon-based monobasic fatty acids (such as linoleic acid and oleic acid), as described especially in EP 0 471 566.

When the diacid is cycloaliphatic, it may comprise the following carbon skeletons: norbornylmethane, cyclohexylmethane, dicyclohexylmethane, dicyclohexylpropane, di (methylcyclohexyl) propane.

If, with the exception of N-heptyl-1-aminoundecanoic acid, fatty acid dimers and cycloaliphatic diamines, the comonomers or starting materials contemplated in the present description (amino acids, diamines, diacids) are effectively linear, nothing forbids to consider that they can in all or part be branched, such as 2-methyl-1, 5-diaminopentane, or partially unsaturated. It will be noted in particular that the C18 dicarboxylic acid may be octadecanedioic acid, which is saturated, or octadecenedioic acid, which has an unsaturation.

Preferably, the polyamide according to the invention has a number of carbon atoms per nitrogen atom greater than 8.

Preferably, the homopolyamide may be chosen from a PA 6.10 homopolyamide obtained by polycondensation of hexanediamine and decanedioic acid, PA B.12 also noted BMACM.12 obtained by polycondensation of bis (3-methyl-4- aminocyclohexyl) -methane and dodecanedioic acid, PA 10.12 obtained by polycondensation of decanediamine and dodecanedioic acid, PA 10.10 obtained by polycondensation of decanediamine and decanedioic acid, PA 6.12 obtained by polycondensation of hexanediamine and decanedioic acid, homopolyamide PA11 obtained by polycondensation of amino-11-undecanoic acid and homopolyamide PA12 obtained by polycondensation of 12-aminododecanoic acid or lauryllactam.

Preferably, the copolyamide may be chosen from the following copolyamides: PA11 / 6.T, PA11 / 10.T, PA11 / B.10, PA11 / 6, PA11 / 6.10, PA11 / 6.12, PA11 / 6.6, PA11 / 10.12 , PA11 / BI / BT

Preferably, the polyamide may be chosen from PAE, PA12, PA 10.10, PA 10.12, PA 6.10, PA11 / 10.T and PA11 / B.10.

The nomenclature used to define polyamides is described in ISO 1874-1: 1992 "Plastics - Polyamide (PA) materials for molding and extrusion - Part 1: Designation", especially on page 3 (Tables 1 and 2) and is well known to those skilled in the art.

The composition according to the invention comprises from 20 to 80%, by weight, and preferably from 30 to 70% by weight relative to the total weight of the composition, of at least one semicrystalline or amorphous polyamide.

The composition according to the invention may also comprise one or more homopolyamides, semi-crystalline copolyamides or amorphous or a mixture of these.

The polyamides according to the invention can be used in the form of granules or in powder form.

Viscosity

Preferably, the polyamide has a melt viscosity of from 1 to 500 Pa.s, in particular from 10 to 500 Pa.s measured at 240 ° C. by oscillatory rheology in plane-plane at 100s shear. ^1. The measurement method used to perform this measurement is as follows:

The tests are performed on μϋΞΜ equipped with screws 1 1 1 and 123 (screw pro wire 2).

The flat temperature profile at 240 ° C is programmed. The various mixtures are made with a screw speed of 100 rpm and a recirculation time of 25 minutes, to which must be added the machine feeding time is between 1 'and 2'. The tests are carried out under a nitrogen sweep (0.5 bar).

The normal force is measured in N. It represents the evolution of the viscosity in the molten state. The viscosity at T0 and its evolution at T + 30 minutes are determined by plane plane oscillatory rheology.

Plan plan: 30 min at 240 ° c 10 rad / sec 5% deformation according to the following operating conditions:

Device: PHYSICA MCR301

Geometry: 25mm parallel planes of diameter

Temperatures: 240 ° C

Frequency: l Orad. s ^"1

Duration: 30minutes

Atmosphere: Nitrogen sweep.

Shear 100s ^"1

chain termination

A homo or a copolyamide terminates in an amino function and an acid function, when it is obtained by polycondensation of amino acids, by polycondensation of lactams, or by polycondensation of diacids and diamines. However, in the latter case, it is also possible to obtain two functions acid or well two functions amine.

According to the present invention, chain terminating agents are compounds capable of reacting with the amine terminal functions of polyamides, thus modifying the reactivity of the amine end of the macromolecule, and thereby controlling the polycondensation of the polyamide and also the stability of the melt viscosity of the composition during its processing.

The termination reaction may for example be illustrated as follows:

Polyamide-NH ₂ + R-C0 ₂ H → polyamide-NH-CO-R + H ₂ 0

Thus, the chain terminating agents suitable for reacting with the amine terminal functions of the polyamide present in the composition according to the invention are mono- or diacids, preferably comprising from 8 to 30 carbon atoms. The diacids can be chosen from adipic acid, decanedioic acid and dodecanedioic acid. The monoacids can be chosen from capric acid, acetic acid, benzoic acid, lauric acid, tridecyl acid, myristic acid, palmitic acid, stearic acid and pivalic acid. and isobutyric acid.

Therefore, when the chain terminating agent is a monoacid, the chain terminator is an alkyl group and when the chain terminator is a diacid, the chain termination is an acidic function.

Preferably, the chain restrictors used in the preparation of the polyamide according to the invention are basic compounds, such as amines, or carboxylic acid compounds having less than 8 carbon atoms.

Preferably, the polyamide according to the invention is not a catalyzed polyamide. This means that it does not have in its catalyst structure. The catalysts usually used during their polycondensation are acids derived from phosphorus. Thus, the polyamide according to the invention does not contain any acid derived from phosphorus, such as ortho, or meta or pyrophosphoric acid, or phosphorous or hypophosphorous acid. Chain length

The polyamide according to the invention may optionally comprise at least one chain extender block.

This chain lengthening block is of structure:

Y-A '-Y

with A 'being a hydrocarbon biradical of nonpolymeric structure (neither polymer, nor ligomer, nor prepolymer), carrying 2 identical terminal reactive functions Yl, reactive by polyaddition (without elimination of reaction by-product), with at least a function at the end of the chain of the block copolymer according to the invention, preferably of molecular weight less than 500 and more preferably less than 400,

in particular Y 1 is chosen from: oxazine, oxazoline, oxazolinone, oxazinone, imidazoline, epoxy, isocyanate, maleimide, cyclic anhydride.

Suitable examples of chain extenders include the following:

when the chain termini are NH 2 or OH functions, preferably NH 2, the Y 1 -A '-Y 1 chain extender corresponds to:

Y l chosen from the groups: maleimide, optionally blocked isocyanate, oxazinone and oxazolinone, cyclic anhydride, preferably oxazinone and oxazolinone, and

A 'is a carbon spacer or carbon radical carrying the functions or reactive groups Y 1, chosen from:

a covalent bond between two functions (groups) Y in the case where Y l = oxazinone and oxazolinone or

an aliphatic hydrocarbon chain or an aromatic hydrocarbon and / or cycloaliphatic chain, the latter two comprising at least one optionally substituted 5- or 6-carbon ring, optionally with said aliphatic hydrocarbon chain optionally having a molecular weight of 14 to 200 g . mo l ^"1 . The Y1-A'-Y1 chain extender may also correspond to a structure in which

Yl is a caprolactam group and

A 'is a carbonyl radical such as carbonyl biscaprolactam or A' may be a terephthaloyl or isophthaloyl.

The chain extender Yl-A'-Yl may also carry a Yl group of cyclic anhydride and preferably this elongator is chosen from a cycloaliphatic and / or aromatic carboxylic dianhydride and more preferably it is chosen from: ethylenetetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, perylenetetracarboxylic dianhydride, 3,3', 4,4'-benzophenone tetracarboxylic dianhydride, dianhydride 1,2,3,4-cyclobutanetetra carboxylic acid, hexafluoroisopropylidene bisphthalic dianhydride, 9,9-bis (trifluoromethyl) xanthenetetracarboxylic dianhydride, 3,3 ', 4,4'-diphenylsulfonetetracarboxylic dianhydride, bicyclo dianhydride [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic acid, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 3,3 ', 4,4'-diphenyl ether tetracarboxylic dianhydride, or mixtures thereof, and

when the chain terminations are COOH functions: said Y1-A'-Y1 chain extender corresponds to:

Yl chosen from the groups: oxazoline, oxazine, imidazoline, aziridine, such as 1, l-iso- or terephthaloyl-bis (2-methyl aziridine) or epoxy,

A 'being a carbon spacer (radical) as defined above.

More particularly, when in said Y1-A'-Y1 extender, said Y1 function is chosen from oxazinone, oxazolinone, oxazine, oxazoline or imidazoline, in particular oxazoline, in this case, in the chain extender represented by Yl-A ' -Yl, A 'may represent alkylene such that - (CH2) m- with m ranging from 1 to 14 and preferably from 2 to 10 or A' may represent cycloalkylene and / or substituted arylene (alkyl) or unsubstituted like benzene arylenes, such as o-, m-, -p phenylenes or naphthalenic arylenes and preferably A 'is arylene and / or cycloalkylene.

In the case where Y 1 is an epoxy, the chain extender can be chosen from bisphenol A diglycidyl ether (DGEBA) and its hydrogenated derivative (cycloaliphatic) bisphenyl diglycidyl ether, tetrabromo bisphenol A diglycidyl ether, or hydroquinone diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol di glycidyl ether, butylene glycol di glycidyl ether, neopentyl glycidyl diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanedio l diglycidyl ether, cyclohexanedimethanol diglycidyl ether, polyethylene glycol glycidyl ether of Mn <500, polypropylene glycol di glycidyl ether of Mn <500, polytetramethylene glycol di glycidyl ether of Mn <500, resorcinol diglycidyl ether, neopentyl glycol di glycidyl ether, bisphenol A po lyethylene glycol di glycidyl ether of Mn <500, bisphenol A polypropylene glycol diglycidyl ether of Mn <500, diglycidyl esters of dicarboxylic acid such as glycidyl ester of acid t or epoxidized diolefins (dienes) epoxidized or epoxidized ethylenically unsaturated double fatty acids, diglycidyl 1,2-cyclohexanedicarboxylate, and mixtures thereof.

In the case of carbonyl- or terephthaloyl- or isophthaloyl-biscaprolactam as chain extender Y 1 -A '-Y 1, the preferred conditions avoid by-product removal, such as caprolactam during said polymerization and implemented at the melted state.

In the eventual case cited above, where Y 1 represents a blocked isocyanate function, this blocking can be obtained by blocking agents of the isocyanate function, such as epsilon-caprolactam, methyl ethyl ketoxime, dimethyl pyrazole, diisocyanate and the like. ethyl malonate.

Likewise, in the case where the extender is a dianhydride that reacts with NH 2 functions derived from the block copolymer, the preferred conditions avoid any imide ring formation during the polymerization and during the melt processing.

For the OH or NH ₂ terminations of the block copolymer, the group Y 1 is preferably chosen from: isocyanate (not blocked), oxazinone and oxazolinone, more preferably oxazinone and oxazo linone, with as spacer (radical) A 'being as defined above.

As examples of chain extenders carrying oxazoline or oxazine reactive functional groups Y that are suitable for the implementation of the invention, reference may be made to those described under references "A", "B", "C" and "D". on page 7 of application EP 0 58 1 642, as well as to their preparation processes and their reaction modes which are exposed to them. "A" in this document is bisoxazole line, "B" bisoxazine, "C" 1,3-phenylene bisoxazoline and "D" 1,4-phenylene bisoxazoline.

By way of example, in the case where the C02H endings of the block copolymer and the Y 1 -A '-Y 1 chain extender is 1,4-phenylene bisoxazoline, the reaction product obtained has at least one recurring pattern of following structure:

-O-C (O) -P-C (O) -O-R 1 -NH-C (O) -A '- C (O) -NH-R 1 - in which:

P is an acid-terminated polyamide HO-C (O) -P-C (O) -OH obtained from the amide units (A), (B) or (C),

Ri (CH ₂ ) ₂ , and

A 'is a phenyl.

As examples of Y 1 imidazo line reactive functional chain extenders suitable for the practice of the invention, reference may be made to those described ("A" to "F") on pages 7 to 8 and Table 1 of page 10 in the application EP 0 739 924 as well as their processes of preparation and their modes of reaction which are exposed therein.

As examples of oxazinone or oxazolinone reactive chain extender Y 1, which are suitable for the practice of the invention, reference may be made to those described under references "A" to "D" on pages 7 to 8. EP 0 58 1641, as well as to their preparation processes and their reaction modes which are exposed to them.

Examples of groups Y l oxazinones (ring with 6 atoms) and oxazo linones (ring with 5 atoms) suitable include groups Y l derived from: benzoxazinone oxazinone or oxazo linone, with as spacer A 'being able to to be a simple covalent bond with respective corresponding elongators being: bis- (benzoxazinone), bisoxazinone and bisoxazolinone.

A 'can also be a C1 to C14 alkylene, preferably a C2 to C10 alkylene, but preferably A' is an arylene and more particularly it can be a phenylene (substituted with Y1 at the 1,2 or 1,3 or 1, 4) or a naphthalene radical (disubstituted with Yl) or phthaloyl (iso- or terephthaloyl) or A 'may be a cycloalkylene.

For Yl functions such as oxazine (6-ring), oxazoline (5-ring) and imidazoline (5-ring), the radical A 'can be as described above with A' being a simple covalent bond and with the extenders respective corresponding ones 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 (substituted by Yl at the 1,2 or 1,3 or 1,4 positions) or a naphthalene (disubstituted by Yl) or phthaloyl radical ( iso- or terephthaloyl) or A 'may be cycloalkylene.

In the case where Y1 = aziridine (nitrogenous heterocycle with 3 atoms equivalent to ethylene oxide by replacing the ether -O- with -NH-), the radical A 'may be a phthaloyl (1,1' iso). or terephthaloyl) with, as an example of such an extender, isophthaloyl-bis (2-methyl aziridine).

The presence of a catalyst for the reaction between the polyamide according to the invention and said Y1-A'-Y1 extender at a level ranging from 0.001 to 2%, preferably from 0.01 to 0.5% by weight. total of two co-reactants mentioned can accelerate the (poly) addition reaction and thus shorten the production cycle. 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.

According to a more particular case of the choice of said extender, A 'may represent an alkylene, such that - (CH2) _m - with m ranging from 1 to 14 and preferably 2 to 10 or is substituted or unsubstituted arylene, such as benzene arylenes (such as o-, m-, -p) or naphthalenic phenylenes (with arylenes: naphthalenylenes). Preferably, A 'represents an arylene which can be benzene or naphthenic substituted or not.

As already stated, said chain extender has a non-polymeric structure and preferably a molecular weight less than 500, more preferably less than 400.

Preferably, the polyamide according to the invention comprises at least one chain extender block located at one or more ends of the polyamide.

The elongated denier rate in said polyamide ranges from 1 to 20%, in particular from 5 to 20%.

Melamine derivatives

The composition according to the invention comprises at least one melamine derivative.

For the purposes of the present invention, melamine derivatives are understood to mean compounds resulting from the action of melamine (1,3,5-triazine-2,4,6-triamine of the empirical formula C ₃ H ₆ N ₆ ) on the acid and, more particularly, the compound resulting from the equimolar reaction of melamine on this acid.

The melamine derivative may be chosen from melamine cyanurate, melamine pyrophosphate and mixtures thereof.

By melamine cyanurate, we mean the compounds resulting from the action of melamine on cyanuric acid and, more particularly, the compound resulting from the equimolar reaction of melamine on cyanuric acid, that this acid is under its control. form eno or keto.

Various companies sell such compounds as "melamine cyanurate".

The composition according to the invention may comprise from 5 to 30% by weight, preferably from 10 to 30% by weight, and more preferably from 10 to 20% by weight relative to the total weight of the composition. at least one melamine derivative. polyols

The composition according to the invention may comprise at least one polyol comprising at least four alcohol functions.

By polyols having at least four alcohol functions, we mean:

tetols such as erythritol, mono pentaerythritol (and its derivatives: di and tripentaerythritol) etc.

- pentols such as xylito l, arabito l etc.

hexols such as mannitol, sorbitol, etc., and higher homologues.

These polyols can, of course, be used alone or in a mixture.

Preferably, the polyol is selected from pentaerythritol, sorbitol, and mixtures thereof.

The composition according to the invention may comprise from 0.5 to 10%, by weight, and preferably from 1 to 5% by weight relative to the total weight of the composition, of at least one polyol.

Preferably, the formulated polyamide represents at least 50% by weight of the total weight of the composition. For the purposes of the present invention, the term "formulated polyamide" means the composition according to the invention without the reinforcing agent (s).

reinforcement

The composition according to the invention may comprise at least one reinforcement in the form of a fiber.

The reinforcement according to the invention may be in the form of continuous fiber, long fiber (continuous or not) or short fiber.

By long fiber is meant according to the present invention a fiber of length to diameter ratio of the fiber, which means that these fibers have a circular section, greater than 1000, preferably greater than 2000. In this assembly, the fibers can be continuous, in the form of unidirectional (UD) or multidirectional (2D, 3D) reinforcement.

In particular, they may be in the form of fabrics, plies, strips or braids and may also be cut by example in the form of nonwovens (mats) or in the form of felts.

These fibers may for example be in the form of a coil, the continuous fiber then being impregnated with the composition (without the reinforcement), and then granulated to the desired size. According to this embodiment, the fiber has the size of the granule and is well continuous over the entire granule.

Preferably, the so-called long fibers have a length of between 0.10 and 250 mm and preferably between 0.1 and 100 mm and in particular between 0.1 and 5 mm.

Preferably, the so-called short fibers are of length between 200 and 400 μπι.

Preferably, the reinforcement in the form of a continuous fiber present in the composition according to the invention is chosen from natural, polymeric or mineral fibers.

These reinforcing fibers may be chosen from:

the mineral fibers, which have melting temperatures Tf that are higher than and higher than the melting temperature Tf of said semi-crystalline polyamide of the invention and that are greater than the polymerization and / or processing temperature;

the polymeric or polymer fibers having a melting point Tf or, in the absence of Tf, a glass transition temperature Tg ', greater than the polymerization temperature or higher than the melting temperature Tf of said semi-crystalline polyamide constituting said matrix of composite and greater than the temperature of implementation

- or the fiber mixtures mentioned above.

Suitable mineral fibers for the invention include carbon fibers, which include carbon nanotube or carbon nanotube (CNT) fibers, carbon nanofibers, or graphenes; silica fibers such as glass fibers, especially of type E, R or S2; boron fibers; ceramic fibers, in particular silicon carbide fibers, boron carbide fibers, boron carbonitride fibers, silicon nitride fibers, boron nitride fibers, basalt fibers; fibers or filaments based on metals and / or their alloys; 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.

More particularly, natural fibers are selected from flax, castor, wood, sisal, kenaf, coconut, hemp and jute fibers.

Preferably, the reinforcement present in the composition according to the invention is chosen from glass fibers, carbon fibers, from linseed fibers and their mixtures, and more preferentially flax fibers and carbon fibers, and more preferentially still carbon fibers.

The composition according to the invention may comprise from 20 to 80%, by weight, and preferably from 30 to 70% by weight, more particularly from 20 to 50% by weight, and still more preferably from 30 to 45% by weight. weight relative to the total weight of the composition, at least one reinforcement.

A coupling agent may be included to improve the adhesion of the fibers to the polyamide, such as silanes or titanates, which are known to those skilled in the art.

Preferred embodiments

According to a first preferred embodiment of the invention, the composition comprises:

at least one polyamide,

melamine cyanurate, and

-the pentaerythrito l.

Preferably, this composition does not contain a reinforcement in the form of fiber.

According to a second preferred embodiment of the invention, the composition comprises:

at least one polyamide,

melamine cyanurate, and

at least one reinforcement in the form of fiber.

Preferably, this composition does not contain polyol comprising at least four times the alcohol function. According to a third preferred embodiment of the invention, the composition comprises:

at least one polyamide,

melamine cyanurate,

from pentaerythritol l, and

at least one reinforcement in the form of fiber.

Preferably, for each of these embodiments, the polyamide has a melt viscosity of between 1 and 500 Pa.s, in particular between 10 and 500 Pa.s measured at 240 ° C. by oscillatory rheology in plan and is selected from PA1 1, PA 12, PA 10. 10, PA 1 0. 12, PA 6. 10, PA 1 1 / 10.T and PA 1 1 / B. 10.

Preferably, the reinforcement is chosen from glass fibers, carbon fibers and flax fibers.

The composition according to the invention may also comprise usual additives for polyamides, such as: colorants, light stabilizers (UV) and / or heat stabilizers, plasticizers, impact modifiers, surface-active agents, pigments, optical brighteners, antioxidants, natural waxes, functional or non-functional polyolefins, crosslinked or otherwise, flame retardants other than those described above, such as a metal salt chosen from a metal salt of phosphinic acid, a metal salt of diphosphinic acid, a polymer containing at least one metal salt of phosphinic acid, a polymer containing at least one metal salt of diphosphinic acid; release agents or fillers, and mixtures thereof.

The envisaged feeds include conventional mineral fillers, such as those selected from the group, given as non-limiting, including talc, kaolin, magnesia, slags, silica, carbon black, carbon nanotubes, expanded graphite or not, titanium oxide.

Preferably, the additives of the composition according to the present invention may be present in an amount of less than or equal to 20%, and preferably less than 10% by weight relative to the weight of the composition. The invention also relates to a method for preparing a composition as defined above. According to this method, the composition may be prepared by any method, which makes it possible to obtain a homogeneous mixture containing the composition according to the invention, and possibly other additives, such as extrusion in the molten state, compacting, or the roll kneader.

The composition according to the invention is prepared by melt blending all the ingredients in a so-called live process.

Advantageously, the composition can be obtained in the form of granules by compounding on a tool known to those skilled in the art such as: twin screw extruder, comalaxer, internal mixer.

The composition according to the invention obtained by the method of preparation described above can then be transformed for subsequent use or processing known to those skilled in the art using tools such as: injection molding machine , extruder, etc.

According to a particular embodiment of the process according to the invention, the composition can be prepared by melt blending of the components with the exception of the reinforcement, when it is present, that is to say polyamide, melamine derivative, optionally polyol and optionally other additives.

This melt blend can be extruded and can then impregnate reinforcing fibers to be granulated.

According to another embodiment, this melt mixture can be extruded, granulated, milled in the form of a powder and can then impregnate reinforcing fibers, to possibly then be granulated.

The invention thus also relates to an article obtained by injection, extrusion, coextrusion or multi-injection from at least one composition as defined above.

The process for preparing the composition according to the invention may also use a twin-screw extruder feeding, without intermediate granulation, an injection molding machine or an extruder according to an implementation device known to those skilled in the art. The composition according to the invention can be used to form a structure. This structure can be monolayer when it is formed only of the composition according to the invention. This structure can also be a multilayer structure, when it comprises at least two layers and that at least one of the various layers forming the structure is formed of the composition according to the invention.

The structure, whether monolayer or multilayer, may especially be in the form of fibers (for example to form a woven or a nonwoven), a film, a sheet, a tube, a hollow body or part injected. For example, films and sheets can be used in fields as varied as those of electronics, electrical and avionics.

The composition according to the invention can be used for the manufacture of housings, connectors, tubes and parts used in the electrical, electronic and avionic fields.

The composition according to the invention may advantageously be envisaged for the production of all or part of items of electrical and electronic equipment goods, such as encapsulated soenoids, pumps, telephones, computers, monitors, camera remotes, circuit breakers, sheaths. electric cables, optical fibers, switches, multimedia systems or sandwich panels. It may also be used for the production of all or part of aeronautical equipment such as tubes, tube connectors, pumps, parts injected in the cockpit or the cabin, such as the walls forming the covering, the elements of the seats ( back, seat, tablet). It can also be used for the production of all or part of automotive equipment such as tubes, tube connectors, pumps, parts injected under the bonnet, injected parts such as bumpers, edge panels, door trim. The elements of automotive equipment, when they have the shape of tubes and / or connectors, can in particular be used in air intake devices, cooling (for example by air, coolant, .. .), transport or transfer of fuels or fluids (such as oil, water, refrigerant, in particular the fluid 1234YF (2,3,3,3-tetrafluoropropene).) It can also be used for the production of all or parts of surgical equipment, packaging or even sports or leisure articles, such as in bicycle equipment (saddle, pedals) .These elements can of course be made antistatic or conductive, by prior addition of suitable amounts of conductive fillers (such as carbon black , carbon fibers, carbon nanotubes, etc.) in the composition according to the invention.

Other objects and advantages of the present invention will appear on reading the following examples given by way of no limitation.

EXAMPLES 1 / Formulation of the compositions

The following compositions A, B and C are prepared: 1. Composition A:

PA 11 is prepared according to the techniques well known to those skilled in the art by anionic polycondensation of amino-1 undecanoic acid, without the addition of catalyst such as H ₃ PO ₄ during the polycondensation. The following composition A is prepared from the compounds, as defined in Table 1 below:

Table 1

The composition is obtained in the form of granules. 1.2. Composition B:

The protocol followed in 1.1. is also followed for composition B, the compounds of which are shown in Table 2 below:

Table 2

1.3. Composition C:

The protocol followed in 1.1. is also followed for the C-position, the compounds of which are shown in Table 3 below:

Table 3 21 Results

The different compositions were the object of two flammability tests, a vertical gantry test 60s and a vertical gantry test 12s according to the standard FAR 25 .853 - 1.

The two tests vertical 60 sec and vertical 12 sec are tests to be made for applications respectively for the interior of airliners and out-of-cab areas or business planes in the case of the second test.

Composite compositions, that is to say containing a fiber, in particular flax, are prepared from the granules of the composition (polyamide matrix and additives) or Rilsan ^® MB 3000 then milled powder form. The fibers, in particular flax, are then impregnated with said powders to obtain the composite plates.

The results are presented below:

FLAMMABILITY test - vertical gantry test 60s time extinguishing time burnt length at

extinction of drops

Composition extinction (cm)

flaming flame (s)

(criterion 15.5 cm)

(criterion 15 s) (criterion 3 s)

Plates injected with 6.5 drops of composition A (average of 3 inflamed

0 values) observed

Composite plates no drops obtained with the 15 12, 1 inflamed composition B observed FLAMMABILITY test - 12s vertical gantry test

Claims

1. Composition comprising:

at least one polyamide,

at least one melamine derivative as flame retardant agent,

optionally at least one polyol comprising at least four times the alcohol function, and

optionally, at least one reinforcement in the form of fiber.

2. Composition according to claim 1, characterized in that it comprises:

at least one polyamide,

at least one melamine derivative as flame retardant, and

at least one polyol comprising at least four times the alcohol function.

3. Composition according to claim 1, characterized in that it comprises:

at least one polyamide,

at least one melamine derivative as flame retardant, and

at least one reinforcement in the form of fiber.

4. Composition according to any one of claims 1 to 3, characterized in that the polyamide is chosen from PA 6.10 obtained by polycondensation of hexanediamine and decanedioic acid, PA B.12 also noted BMACM.12 obtained by polycondensation of bis- (3-methyl-4-aminocyclohexyl) -methane and dodecanedioic acid, PA 10.12 obtained by polycondensation of decanediamine and dodecanedioic acid, PA 10.10 obtained by polycondensation of decanediamine and of decanedioic acid, PA 6.12 obtained by polycondensation of hexanediamine and decanedioic acid, homopolyamide PAU obtained by polycondensation of amino-11-undecanoic acid, homopolyamide PA12 obtained by polycondensation of 12-aminododecanoic acid or lauryllactam, PA11 / 6.T, PA11 / 10.T, PA11 / B.10, PA11 / 6, PA11 / 6.10, PA11 / 6.12, PA11 / 6.6, PA11 / 10.12, PA11 / BI / BT

5. Composition according to Claim 4, characterized in that the polyamide is chosen from among PAU, PA12, PA 10.10, PA 10.12, PA 6.10, PA11 / 10.T and PA11 / B.10.

6. Composition according to any one of claims 1 to

5, characterized in that the polyamide has a melt viscosity of between 1 and 500 Pa.s, in particular between 10 and 500 Pa.s, measured at 240 ° C. by oscillatory rheology in plane-plane.

7. Composition according to any one of claims 1 to

6, characterized in that it comprises from 20 to 80%, by weight, and preferably from 30 and 70% by weight relative to the total weight of the composition, of at least one polyamide.

8. Composition according to any one of claims 1 to 7, characterized in that the melamine derivative is selected from melamine cyanurate, melamine pyrophosphate and mixtures thereof.

9. Composition according to any one of claims 1 to 8, characterized in that it comprises from 5 to 30%> by weight, preferably from 10 to 30%> by weight, and more preferably from 10 to 20% by weight relative to the total weight of the composition, of at least one melamine derivative.

10. Composition according to any one of claims 1, 2 and 4 to 9, characterized in that the polyol is selected from erythritol, mono pentaerythritol, dipentaerythritol, tripentaerythritol, xylitol, arabitol, mannitol , sorbitol and their mixture.

11. The composition as claimed in claim 1, wherein the composition comprises from 0.5 to 10% by weight, the total weight of the composition of at least one polyol.

12. Composition according to any one of claims 1 and

3 to 11, characterized in that the reinforcement is chosen from continuous fibers, long or short.

13. Composition according to any one of claims 1 and 3 to 12, characterized in that the reinforcement is selected from the fibers natural, polymeric or mineral.

14. Composition according to any one of claims 1 and 3 to 13, characterized in that the reinforcement is selected from glass fibers, carbon fibers, flax fibers and mixtures thereof.

15. Composition according to any one of claims 1 and

3 to 14, characterized in that the composition comprises from 20 to 80%, by weight, and preferably from 30 to 70% by weight, more particularly from 20 to 50% by weight and still more preferably from 30 to 45% by weight. % by weight relative to the total weight of the composition, of at least one reinforcement.

16. Composition according to any one of the preceding claims, characterized in that it comprises at least one additive chosen from colorants, stabilizers, in particular UV, plasticizers, impact modifiers, surfactants, pigments, optical brighteners, anti-oxidants, natural waxes, polyolefins, release agents, fillers and mixtures thereof.

17. Composition according to any one of the preceding claims, characterized in that it is in the form of an injected part, of fibers, of a powder, of a film, of a sheet, of a tube or a hollow body.

8. Process for the preparation of the composition as defined in any one of the preceding claims, characterized in that the composition is prepared by melt blending of all the ingredients as defined in the preceding claims.

19. Use of the composition as defined in any one of claims 1 to 17 for the manufacture of housings, connectors, tubes and parts used in the electrical, electronic and avionics fields.

20. Article obtained by injection, extrusion, coextrusion, multi-injection from at least one composition as defined in any one of claims 1 to 17.