INSULATING AND FIRE-RETARDANT POLYAMIDE COMPOSITE FOR COVERING ELECTRICAL BATTERY INTERCONNECTION BARS

Abstract

The present invention relates to an insulating and flame-retardant composition for covering an electric battery interconnecting bar comprising by weight: (a) 30 to 65%, in particular 30 to 63.9%, notably 30 to 60% of at least one semi-crystalline aliphatic polyamide, (b) 15 to 40%, in particular 15 to 30% of at least one semi-aromatic polyamide, (c) 15 to 30%, in particular 20 to 25% of at least one phosphinate-type flame retardant, (d) 5 to 20%, in particular 5 to 15% of at least one functionalized polyolefin, (e) 0 to 6%, in particular 1 to 6%, notably between 2 and 4% of at least one plasticizer. (f) from 0 to 10%, in particular from 0.1 to 5% of at least one of the additives, the sum of the constituents (a) to (f) being equal to 100%.

Description

Title of the invention: INSULATING AND FIRE-RETARDANT POLYAMIDE COMPOSITION FOR COATING ELECTRICAL BATTERY INTERCONNECTION BAR

[0001] The invention relates to insulating and flame-retardant polyamide compositions for covering electric battery interconnection bars. Previous technique

[0002] In the field of electric vehicles, connectors called busbars are used to conduct high-intensity current into and out of the batteries. These busbars must be protected by an insulating coating that is resistant to mechanical stress and aging. Given the potential consequences of a fire in such an environment, the coating must also exhibit excellent fire resistance.

[0003] Several processes exist for preparing busbars. The main one is the extrusion of the polymer around the central copper strip. This structure is then cut and bent (at room temperature) to adopt the shape required by the vehicle's layout. For the most complex busbar shapes, powder coating can also be used with specific grades.

[0004] The technical challenge related to the busbar application for batteries lies in forming a thin polymer layer that is fire-resistant (UL94 V0 at 0.8 mm), while maintaining a high level of flexibility to accommodate the deformation of the busbars. During bending, a material that is too rigid forms cracks on the outer face and "waves" or "bulges" on the inner face, phenomena that are unacceptable for the application.

[0005] The material's behavior at the yield stress threshold is therefore crucial. Low threshold stresses and high elongation at the threshold are desired.

[0006] The deformation levels of these coatings remain low, but the material must nevertheless exhibit an elongation at break > 50%. Good abrasion resistance is also necessary for this application.

[0007] The coating must also act as an electrical insulator, which is reflected in properties such as breakdown voltage, dielectric strength, and comparative tracking index (CTI) > 600V. This insulation must be maintained during accelerated thermal aging up to 150°C.

[0008] Finally, the rheological properties of the alloy must be adapted to the extrusion of thin polymer film of the order of 0.5 mm.

[0009] The most frequently used flame retardants in polyamide compositions (PA) are those belonging to the phosphinate family. Their mode of action and thermal stability make them particularly well-suited to polyamide matrices. Thus, US patent 2006 / 0084734 describes phosphinate flame retardants and their preparation, and US patent 2005 / 0014874 describes examples of the use of these phosphinates in flame retardant treatment of aromatic or semi-aromatic polyamides. This patent application provides information on the superior fire resistance of semi-aromatic polyamides (PPA) compared to aliphatic PAs in the presence of a phosphinate flame retardant.

[0010] Furthermore, patent application EP 1741753 describes compositions of this type of flame retardant in a mixture of aliphatic and semi-aromatic PAs in the presence of inorganic reinforcement (glass fiber). In this patent application, the phosphinate flame retardant is necessarily combined with a melamine-based nitrogen synergist.

[0011] Finally, in the railway sector, the US patent application 20170037198 presents formulations based on PA12 plasticized and flame retardanted by phosphinates with optional shock modifiers polyolefin and / or Peba.

[0012] Nevertheless, these various documents provide information on how to obtain a fire-resistant or ductile PA. However, it is difficult to obtain a product with a thin profile that is both ductile and fire-resistant. In the prior art cited, only formulations with glass fibers achieve UL94 V0 at 0.8 mm. Alloys without glass fibers achieve UL94 at greater thicknesses. However, the thinner the profile, the more difficult it is to achieve fire resistance.

[0013] Moreover, the prior art does not provide information on the combinations to be made within the formulation to simultaneously achieve the flexibility and fire resistance required for the battery busbar application.

[0014] The present invention therefore relates to an insulating and flame-retardant composition for covering an electric battery interconnection busbar comprising by weight:

[0015] (a) from 30 to 65%, in particular from 30 to 63.9%, notably from 30 to 60% of at least a semi-crystalline aliphatic polyamide,

[0016] (b) from 15 to 40%, in particular from 15 to 30% of at least one semi-polyamide aromatic,

[0017] (c) 15 to 30%, in particular 20 to 25% of at least one type of flame retardant phosphinate,

[0018] (d) from 5 to 20%, in particular from 5 to 15% of at least one functionalized polyolefin,

[0019] (e) from 0 to 6%, in particular from 1 to 6%, especially between 2 and 4% of at least one plasticizer.

[0020] (f) from 0 to 10%, in particular from 0.1 to 5% of at least one of the additives,

[0021] the sum of the constituents (a) to (f) being equal to 100%.

[0022] The inventors therefore found that a mixture of semi-crystalline aliphatic polyamides and semi-aromatic polyamides in particular proportions associated a phosphinate-type flame retardant and a functionalized polyolefin, both in a specific proportion, with optionally a plasticizer and additives, made it possible to create a composition meeting the criteria for the battery busbar application detailed above.

[0023] Covering the interconnecting bar with the composition of the invention allows the latter to be protected by an insulating coating that is resistant to fire, mechanical stresses and aging.

[0024] Said interconnection bar is located inside and / or outside electric batteries, in particular electric vehicle batteries, in particular motor vehicle batteries.

[0025] Regarding semi-crystalline aliphatic polyamide (a)

[0026] Said at least one semi-crystalline aliphatic polyamide (a) is present from 30 to 65%, in particular from 30 to 63.9%, notably from 30 to 60% by weight in the composition.

[0027] Semi-crystalline polyamide is understood to be a material which is generally solid at room temperature, and which softens when the temperature increases, in particular after passing its glass transition temperature (Tg), and which may exhibit a clear melting when passing its so-called melting temperature (Tf), and which becomes solid again when the temperature decreases below its crystallization temperature.

[0028] Tg, Te and Tf are determined by differential scanning calorimetry (DSC) according to standard 11357-2:2013 and 11357-3:2013 respectively.

[0029] The number-average molecular weight Mn of said semi-crystalline polyamide is preferably in a range from 10,000 to 85,000, in particular from 10,000 to 60,000, preferably from 10,000 to 50,000, even more preferably from 12,000 to 50,000. These Mn values ​​can correspond to inherent viscosities greater than or equal to 0.8 as determined in m-cresol according to ISO 307:2007 but by changing the solvent (using m-cresol instead of sulfuric acid and the temperature being 20°C).

[0030] The nomenclature used to define polyamides is described in ISO 1874-1:2011 "Plastics - Polyamide (PA) materials for molding and extrusion - Part 1: Designation", in particular on page 3 (tables 1 and 2) and is well known to those skilled in the art.

[0031] The term polyamide includes both homopolyamides and copolyamides.

[0032] Said at least one aliphatic semi-crystalline polyamide is obtained from the polycondensation of at least one lactam, or from the polycondensation of at least one amino acid, or from the polycondensation of at least one diamine X with at least one dicarboxylic acid Y or mixtures thereof.

[0033] When said at least one aliphatic semi-crystalline polyamide is obtained from the polycondensation of at least one lactam, said at least one lactam may be chosen from a lactam in C8 to Cl8, preferably in C10 to C18, more preferably in C10 to C12. A lactam in C8 to Cl8 is notably decanolactam, undecanolactam, and lauryllactam.

[0034] When said at least one aliphatic semi-crystalline polyamide is obtained from the polycondensation of at least one lactam, it may therefore comprise a single lactam or several lactams.

[0035] Advantageously, said at least one aliphatic semi-crystalline polyamide is obtained from the polycondensation of a single lactam and said lactam is chosen from lauryllactam and undecanolactam, advantageously lauryllactam.

[0036] When said at least one aliphatic semi-crystalline polyamide is obtained from the polycondensation of at least one amino acid, said at least one amino acid may be chosen from an amino acid in C8 to C18, preferably in C10 to C18, more preferably in C10 to C12.

[0037] A C8 to C18 amino acid is in particular 9-aminononanoic acid, 10-aminodecanoic acid, 10-aminoundecanoic acid, 12-aminododecanoic acid and 11-aminoundecanoic acid and its derivatives, in particular N-heptyl-11-aminoundecanoic acid.

[0038] When said at least one aliphatic semi-crystalline polyamide is obtained from the polycondensation of at least one amino acid, it may therefore comprise a single amino acid or several amino acids.

[0039] Advantageously, said aliphatic semi-crystalline polyamide is obtained from the polycondensation of a single amino acid and said amino acid is selected from 10-aminodecanoic acid, 11-aminoundecanoic acid and 12-aminododecanoic acid, advantageously 11-aminoundecanoic acid.

[0040] When said at least one aliphatic semi-crystalline polyamide is obtained from the polycondensation of at least one diamine X in C6-C36, preferably C6-C18, preferably C6-C12, more preferably C10-C12, with at least one diacid Y in C6-C36, preferably C6-C18, preferably C6-C12, more preferably C10-C12, then said at least one diamine in X is an aliphatic diamine and said at least one diacid Y is an aliphatic diacid.

[0041] The diamine can be linear or branched. Advantageously, it is linear.

[0042] Said at least one diamine X in C6-C36 may in particular be selected from 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethyldiamine, 1,13-tridecamethylenediamine, 1,14-tetradecamethylenediamine, 1,16-hexadecamethylenediamine and the 1,18-octadecamethylenediamine, octadecenediamine, reicosanediamine, docosa-nediamine and diamines obtained from fatty acids.

[0043] Advantageously, said at least one diamine X is in C6-C18 and selected from 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine, 1,13-tridecamethylenediamine, 1,14-tetradecamethylenediamine, 1,16-hexadecamethylenediamine and 1,18-octadecamethylenediamine.

[0044] Advantageously, said at least one diamine X in C6 to C12, is in particular selected from 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine.

[0045] Advantageously, said at least one diamine X in C6 to C12, is in particular selected from 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine.

[0046] Advantageously, the diamine X used is in C12 C10, in particular chosen from 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine.

[0047] Said at least one dicarboxylic acid Y in C6 to C36 may be selected from adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid, and diacids obtained from fatty acids.

[0048] The diacid can be linear or branched. Advantageously, it is linear.

[0049] Advantageously, said at least one dicarboxylic acid Y is in C6 to Cl8 and is selected from adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid.

[0050] Advantageously, said at least one dicarboxylic acid Y is in C6 to C12 and is selected from adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid.

[0051] Advantageously, said at least one dicarboxylic acid Y is in C12 C10 and is selected from sebacic acid, undecanedioic acid, dodecanedioic acid.

[0052] When said aliphatic semi-crystalline polyamide is obtained from the polycondensation of at least one diamine X with at least one dicarboxylic acid Y it can therefore comprise a single diamine or several diamines and a single dicarboxylic acid or several dicarboxylic acids.

[0053] Advantageously, said aliphatic semi-crystalline polyamide is obtained from the polycondensation of a single diamine X with a single dicarboxylic acid Y.

[0054] In one embodiment, said at least one polyamide is a long-chain polyamide having a number of carbons per nitrogen atom greater than or equal to 8, in particular greater than or equal to 9, especially greater than or equal to 10.

[0055] In another embodiment, said at least one semi-crystalline aliphatic polyamide is selected from the polyamides PA610, PA612, PA1010, PA1012, PAU and PA12.

[0056] Advantageously, said at least one semi-crystalline aliphatic polyamide is selected from the polyamides PA 1010, PA 1012, PA11 and PA 12, in particular from PA11 and PA 12, notably PAU. Regarding semi-aromatic polyamide (b)

[0057] Said at least one semi-aromatic polyamide (b) is present from 15 to 40%, in particular from 15 to 30% by weight in the composition.

[0058] In one embodiment, the semi-aromatic polyamide is a semi-crystalline semi-aromatic polyamide, in particular a semi-aromatic polyamide of formula X / YAr, as described in EPI505099, in particular a semi-aromatic polyamide of formula A / XT in which A is selected from a motif obtained from an amino acid, a motif obtained from a lactam and a motif corresponding to the formula (Ca diamine).(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, advantageously between 9 and 18, the (Ca diamine) motif being selected from aliphatic diamines, linear or branched, cycloaliphatic diamines and alkylaromatic diamines and the (Cb diacid) motif being selected from aliphatic diacids, linear or branched, cycloaliphatic diacids and aromatic diacids;

[0059] XT designates a motif obtained from the polycondensation of a Cx diamine and terephthalic acid, with x representing the number of carbon atoms of the Cx diamine, x being between 5 and 36, advantageously between 9 and 18, in particular a polyamide of formula A / 5T, A / 6T, A / 9T, A / 10T or A / 1T, A being as defined above, in particular a polyamide selected from PA MPMDT / 6T, PA11 / 10T, PA 5T / 10T, PA 11 / BACT, PA 11 / 6T / 10T, PA MXDT / 10T, PA MPMDT / 10T, PA BACT / 10T, PA BACT / 6T, PA BACT / 10T / 6T, PA 11 / BACT / 6T, PA 11 / MPMDT / 6T, PA 11 / MPMDT / 10T, PA 11 / BACT / 10T, one PA 11 / MXDT / 10T, an 11 / 5T / 10T.

[0060] In particular, the semi-aromatic semi-crystalline polyamide is selected from polyamide 11 / 5T or 11 / 6T or 11 / 10T, MXDT / 10T, MPMDT / 10T and BACT / 10T.

[0061] T corresponds to terephthalic acid, MXD corresponds to m-xylylene diamine, MPMD corresponds to methylpentamethylene diamine and BAC corresponds to bis(aminomethyl)cyclohexane.

[0062] In another embodiment, said at least one semi-aromatic polyamide is a polyamide of formula XiY, XiY being a repeating motif obtained from the polycondensation of a diamine (Xi) selected from an arylamine, and at least one aliphatic dicarboxylic acid (Y) as defined above.

[0063] Advantageously, in this embodiment, the arylamine is chosen from the meta-xylylene diamine (MXD, CAS No.: 1477-55-0) or para-xylylene diamine (PXD, CAS No.: 539-48-0).

[0064] In another embodiment, said at least one semi-aromatic polyamide is a polyamide of formula MXDY in which MXD corresponds to meta-xylylene diamine and Y is an aliphatic dicarboxylic acid in C6 to Cl8, in particular in C9 to Cl8, especially in C9 to C12.

[0065] Advantageously, said semi-aromatic polyamide of formula MXDY is selected from MXD6, MXD10 and MXD12, in particular MXD10.

[0066] Regarding the phosphinate-type flame retardant (c)

[0067] Said at least one phosphinate-type flame retardant (c) is present from 15 to 30%, in particular from 20 to 25% by weight in the composition.

[0068] The flame retardant is in particular a metallic salt selected from a metallic salt of phosphinic acid, a metallic salt of diphosphinic acid, a polymer containing at least one metallic salt of phosphinic acid, or a polymer containing at least one metallic salt of diphosphinic acid. The flame retardant may also be a mixture of the aforementioned flame retardants.

[0069] The flame retardant may also be chosen from the following metallic salt of phosphinic acid of formula (I) and the following metallic salt of diphosphinic acid of formula (II): m+ n m+-

[0070] with

[0071] RI and R2, independently of each other, denote a linear or branched C1-C6 alkyl group, or an aryl group;

[0072] R3 represents a linear or branched C1-C10 alkylene group, a C6-C10 arylene group, a C6-C10 alkylarylene group, or a C6-C10 arylalkylene group,

[0073] M is an ion of Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K and / or a protonated amine base

[0074] m denotes an integer from 1 to 4,

[0075] n denotes an integer from 1 to 4,

[0076] x denotes an integer from 1 to 4,

[0077] n and m being chosen so that the salt is neutral, that is to say, that it does not carry an electric charge.

[0078] Preferably, M represents a calcium, magnesium, aluminum or zinc ion.

[0079] Preferably, RI and R2, independently of each other, denote a group methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl and / or phenyl.

[0080] Preferably, R3 represents a group of methylene, ethylene, n-propylene, isopropylene, n-butylene, tert-butylene, n-pentylene, n-octylene, n-dodecylene; phenylene, naphthylene; methylphenylene, ethylphenylene, tert-butylphenylene, methylnaphthylene, ethylnaphthylene, tert-butylnaphthylene; phenylmethylene, phenylethylene, phenylpropylene, or phenylbutylene. Regarding functionalized polyolefin (d)

[0081] Said at least one functionalized polyolefin (d) is present from 5 to 20%, in particular from 5 to 15% by weight in the composition.

[0082] The functionalized polyolefin can be a polymer of alpha olefins having reactive motifs (the functionalities); such reactive motifs are acid, anhydride, or epoxy functions. By way of example, one can cite the preceding polyolefins (B2) grafted or co- or ter-polymerized with unsaturated epoxides such as glycidyl (meth)acrylate, or with carboxylic acids or their corresponding salts or esters such as (meth)acrylic acid (which can be totally or partially neutralized by metals such as Zn, etc.) or with carboxylic acid anhydrides such as maleic anhydride. A functionalized polyolefin is for example a PE / EPR mixture, the weight ratio of which can vary widely, for example between 40 / 60 and 90 / 10, said mixture being co-grafted with an anhydride, in particular maleic anhydride, according to a grafting rate for example of 0.01 to 5% by weight.

[0083] The functionalized polyolefin can be selected from the following (co)polymers, grafted with maleic anhydride or glycidyl methacrylate, in which the grafting ratio is, for example, from 0.01 to 5% by weight:

[0084] - PE, PP, copolymers of ethylene with propylene, butene, hexene, or octene containing, for example, 35 to 80% by weight of ethylene;

[0085] - ethylene / alpha-olefin copolymers such as ethylene / propylene, EPR (abbreviation for ethylene-propylene-rubber) and ethylene / propylene / diene (EPDM).

[0086] - styrene / ethylene-butene / styrene block copolymers (SEBS), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), styrene / ethylene-propylene / styrene (SEPS).

[0087] - ethylene and vinyl acetate (EVA) copolymers, containing up to 40% in weight of vinyl acetate;

[0088] - ethylene and alkyl (meth)acrylate copolymers, containing up to 40% in weight of alkyl (meth)acrylate;

[0089] - ethylene and vinyl acetate (EVA) and alkyl (meth)acrylate copolymers, containing up to 40% by weight of comonomers.

[0090] The functionalized polyolefin can also be selected from ethylene / propylene copolymers major in propylene grafted with maleic anhydride and then condensed with mono-amino polyamide (or a polyamide oligomer) (products described in EP-A-0342066).

[0091] The functionalized polyolefin can also be a co- or ter polymer of at least the following motifs: (1) ethylene, (2) alkyl (meth)acrylate or saturated carboxylic acid vinyl ester and (3) anhydride such as maleic anhydride or (meth)acrylic acid or epoxy such as glycidyl (meth)acrylate.

[0092] As an example of functionalized polyolefins of this latter type, the following copolymers may be cited, where ethylene preferably represents at least 60% by weight and where the ter monomer (the function) represents, for example, from 0.1 to 10% by weight of the copolymer:

[0093] - ethylene / alkyl (meth)acrylate / (meth)acrylic acid copolymers or maleic anhydride or glycidyl methacrylate;

[0094] - ethylene / vinyl acetate / maleic anhydride or methacrylate copolymers glycidyl;

[0095] - ethylene / vinyl acetate or alkyl (meth)acrylate / acid copolymers (meth)acrylic or maleic anhydride or glycidyl methacrylate.

[0096] In the preceding copolymers, (meth)acrylic acid can be salified with Zn or Li.

[0097] The term "alkyl (meth)acrylate" refers to methyl acrylates and alkyl acrylates in Cl to C8, and may be selected from methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, ethyl-2-hexyl acrylate, cyclohexyl acrylate, methyl methacrylate and ethyl methacrylate.

[0098] Furthermore, the aforementioned functionalized polyolefins can also be crosslinked by any suitable process or agent (diepoxy, diacid, peroxide, etc.); the term functionalized polyolefin also includes mixtures of the aforementioned polyolefins with a difunctional reagent such as a diacid, dianhydride, diepoxy, etc. capable of reacting with them or mixtures of at least two functionalized polyolefins capable of reacting with each other.

[0099] The copolymers mentioned above can be copolymerized statistically or sequentially and have a linear or branched structure.

[0100] The molecular weight, MFI, and density of these polyolefins can also vary considerably, a fact that those skilled in the art will appreciate. MFI, short for Melt Flow Index, is the melt flow index. It is measured according to ASTM 1238.

[0101] In one embodiment, the polyolefin is cross-linked. Regarding the plasticizer (e)

[0102] Said at least one plasticizer (e) may be present from 0 to 6%, in particular from 1 to 6%, notably between 2 and 4% by weight in the composition.

[0103] The plasticizer may be a plasticizer commonly used in polyamide(s)-based compositions.

[0104] Advantageously, a plasticizer is used which has good thermal stability so that no fumes are formed during the mixing steps of the different polymers and the transformation of the composition obtained.

[0105] In particular, this plasticizer may be selected from:

[0106] Benzene sulfonamide derivatives such as n-butyl benzene sulfonamide (BBSA), the ortho and para isomers of ethyl toluene sulfonamide (ETSA), N-cyclohexyl toluene sulfonamide and N-(2-hydroxypropyl) benzene sulfonamide (HP-BSA),

[0107] hydroxybenzoic acid esters such as ethyl-2-hexyl para-hydroxybenzoate (EHPB) and decyl-2-hexyl para-hydroxybenzoate (HDPB),

[0108] the esters or ethers of tetrahydrofurfuryl alcohol such as oligoethyleneoxy-tetrahydrofurfuryl alcohol, and

[0109] esters of citric acid or hydroxymalonic acid, such as oligoethyleneoxymalonate.

[0110] A preferred plasticizer is n-butyl benzene sulfonamide (BBSA).

[0111] Another particularly preferred plasticizer is N-(2-hydroxypropyl)benzenesulfonamide (HP-BSA). The latter has the advantage of preventing the formation of deposits at the screw and / or the extrusion die ("die tears") during an extrusion transformation step.

[0112] A mixture of plasticizers can obviously be used. Regarding additives (f)

[0113] Said at least one of additive (f) may be present from 0 to 10%, in particular from 0.1 to 5% by weight in the composition.

[0114] At least one additive may be selected from stabilizers, colorants, processing aids, surfactants, nucleating agents, pigments, brighteners, antioxidants, lubricants, waxes, flame retardant synergists, or a mixture thereof.

[0115] By way of example, the stabilizer may be a UV stabilizer, an organic stabilizer or more generally a combination of organic stabilizers, such as a phenol-type antioxidant (for example, of the type of that of irganox® 245 or 1098 or 1010 from Ciba-BASF), a phosphite-type antioxidant (for example, irgafos® 126 or Irgafos® 168 from Ciba-BASF) and possibly other stabilizers such as a HALS, which means Hindered Amine Light Stabiliser or hindered amine-type light stabilizer (for example, Tinuvin® 770 from Ciba-BASF), an anti-UV (for example, Tinuvin® 312 from Ciba), a phosphorus-based stabilizer. One can also use amine-type antioxidants such as Naugard® 445 from Crompton or polyfunctional stabilizers such as Nylostab® S-EED from Clariant.

[0116] This stabilizer can also be a mineral stabilizer, such as a copper-based stabilizer. Examples of such mineral stabilizers include copper halides and copper acetates. Other metals, such as silver, could also be considered, but these are known to be less effective. These copper-based compounds are typically associated with alkali metal halides, particularly potassium.

[0117] Synergistic flame retardant agents include, in particular, those described in WO2005121234.

[0118] They can be chosen from nitrogen synergists and phosphorus / nitrogen synergists.

[0119] Nitrogen synergists preferably include benzoguanamine, tris(hydroxyethyl)isocyanurate, allantoin, glycolurile, melamine, melamine cyanurate, dicyandiamide, guanidine, carbodiimides.

[0120] Nitrogen synergists preferably comprise melamine condensation products. By way of example, melamine condensation products are the melem, melam or melon, or compounds of this type with a higher condensation rate, or a mixture of these, and, by way of example, may be prepared by the process described in the United States 5,985,960.

[0121] Phosphorus / nitrogen synergists may include reaction products of melamine with phosphoric acid or with condensed phosphoric acids, or include reaction products of condensation products of melamine with phosphoric acid or condensed phosphoric acids, or include a mixture of the specified products.

[0122] In one embodiment, the additives are chosen from antioxidants, colour pigments and flame retardant synergists, in particular nitrogen synergists, especially melamine-based. Regarding the composition

[0123] Said insulating and flame-retardant composition for covering an electric battery interconnection busbar comprises by weight:

[0124] (a) from 30 to 65%, in particular from 30 to 63.9%, in particular from 30 to 60% of at least a semi-crystalline aliphatic polyamide,

[0125] (b) from 15 to 40%, in particular from 15 to 30% of at least one semi-polyamide aromatic,

[0126] (c) 15 to 30%, in particular 20 to 25% of at least one type of flame retardant phosphinate,

[0127] (d) from 5 to 20%, in particular from 5 to 15% of at least one functionalized polyolefin,

[0128] (e) from 0 to 6%, in particular from 1 to 6%, in particular between 2 and 4% of at least one plasticizer.

[0129] (f) from 0 to 10%, in particular from 0.1 to 5% of at least one of the additives

[0130] the sum of the constituents (a) to (f) being equal to 100%.

[0131] Advantageously, said insulating and flame-retardant composition for covering an electric battery interconnecting busbar consists, by weight:

[0132] (a) from 30 to 65%, in particular from 30 to 63.9%, in particular from 30 to 60% of at least a semi-crystalline aliphatic polyamide,

[0133] (b) from 15 to 40%, in particular from 15 to 30% of at least one semi-polyamide aromatic,

[0134] (c) 15 to 30%, in particular 20 to 25% of at least one type of flame retardant phosphinate,

[0135] (d) from 5 to 20%, in particular from 5 to 15% of at least one functionalized polyolefin,

[0136] (e) from 0 to 6%, in particular from 1 to 6%, in particular between 2 and 4% of at least one plasticizer.

[0137] (f) from 0 to 10%, in particular from 0.1 to 5% of at least one of the additives

[0138] the sum of the constituents (a) to (f) being equal to 100%.

[0139] In a first variant, said composition comprises by weight:

[0140] (a) from 30 to 64%, in particular from 30 to 60% of at least one semi-aliphatic polyamide crystalline,

[0141] (b) from 15 to 40%, in particular from 15 to 30% of at least one semi-polyamide aromatic,

[0142] (c) 15 to 30%, in particular 20 to 25% of at least one type of flame retardant phosphinate,

[0143] (d) from 5 to 20%, in particular from 5 to 15% of at least one functionalized polyolefin,

[0144] (e) from 1 to 6% in particular between 2 and 4% of at least one plasticizer.

[0145] (f) from 0 to 10%, in particular from 0.1 to 5% of at least one of the additives

[0146] the sum of the constituents (a) to (f) being equal to 100%.

[0147] In one embodiment of this first variant, said composition includes by weight:

[0148] (a) from 30 to 64%, in particular from 30 to 60% of at least one semi-aliphatic polyamide crystalline,

[0149] (b) of 15 to 30% of at least one semi-aromatic polyamide,

[0150] (c) 15 to 30%, in particular 20 to 25% of at least one type of flame retardant phosphinate,

[0151] (d) from 5 to 20%, in particular from 5 to 15% of at least one functionalized polyolefin,

[0152] (e) from 1 to 6% in particular between 2 and 4% of at least one plasticizer.

[0153] (f) from 0 to 10%, in particular from 0.1 to 5% of at least one of the additives

[0154] the sum of the constituents (a) to (f) being equal to 100%.

[0155] Advantageously, said composition comprises by weight:

[0156] (a) of 30 to 59% of at least one semi-crystalline aliphatic polyamide,

[0157] (b) of 15 to 30% of at least one semi-aromatic polyamide,

[0158] (c) 20 to 25% of at least one phosphinate-type flame retardant,

[0159] (d) from 5 to 20%, in particular from 5 to 15% of at least one functionalized polyolefin,

[0160] (e) from 1 to 6% in particular between 2 and 4% of at least one plasticizer.

[0161] (f) from 0 to 10%, in particular from 0.1 to 5% of at least one of the additives

[0162] the sum of the constituents (a) to (f) being equal to 100%.

[0163] More advantageously, said composition comprises by weight:

[0164] (a) from 30 to 64%, in particular from 30 to 60% of at least one semi-aliphatic polyamide crystalline,

[0165] (b) of 15 to 30% of at least one semi-aromatic polyamide,

[0166] (c) 15 to 30%, in particular 20 to 25% of at least one type of flame retardant phosphinate,

[0167] (d) of 5 to 15% of at least one functionalized polyolefin,

[0168] (e) from 1 to 6% in particular between 2 and 4% of at least one plasticizer.

[0169] (f) from 0 to 10%, in particular from 0.1 to 5% of at least one of the additives

[0170] the sum of the constituents (a) to (f) being equal to 100%.

[0171] Even more advantageously, said composition comprises by weight:

[0172] (a) of 30 to 59% of at least one semi-crystalline aliphatic polyamide,

[0173] (b) of 15 to 30% of at least one semi-aromatic polyamide,

[0174] (c) 20 to 25% of at least one phosphinate-type flame retardant,

[0175] (d) 5 to 15% of at least one functionalized polyolefin,

[0176] (e) from 1 to 6% in particular between 2 and 4% of at least one plasticizer.

[0177] (f) from 0 to 10%, in particular from 0.1 to 5% of at least one of the additives

[0178] the sum of the constituents (a) to (f) being equal to 100%.

[0179] Even more advantageously, said composition comprises by weight:

[0180] (a) from 30 to 58.9% of at least one semi-crystalline aliphatic polyamide,

[0181] (b) of 15 to 30% of at least one semi-aromatic polyamide,

[0182] (c) 20 to 25% of at least one phosphinate-type flame retardant,

[0183] (d) 5 to 15% of at least one functionalized polyolefin,

[0184] (e) from 1 to 6% in particular between 2 and 4% of at least one plasticizer.

[0185] (f) 0.1 to 5% of at least one of the additives

[0186] the sum of the constituents (a) to (f) being equal to 100%.

[0187] In a second variant, said composition comprises by weight:

[0188] (a) of 30 to 59% of at least one semi-crystalline aliphatic polyamide,

[0189] (b) from 15 to 40%, in particular from 15 to 30% of at least one semi-polyamide aromatic,

[0190] (c) 20 to 25% of at least one phosphinate-type flame retardant,

[0191] (d) from 5 to 20%, in particular from 5 to 15% of at least one functionalized polyolefin,

[0192] (e) from 1 to 6% in particular between 2 and 4% of at least one plasticizer.

[0193] (f) from 0 to 10%, in particular from 0.1 to 5% of at least one of the additives

[0194] the sum of the constituents (a) to (f) being equal to 100%.

[0195] In one embodiment of this second variant, said composition comprises by weight:

[0196] (a) of 30 to 59% of at least one semi-crystalline aliphatic polyamide,

[0197] (b) from 15 to 40%, in particular from 15 to 30% of at least one semi-polyamide aromatic,

[0198] (c) 20 to 25% of at least one phosphinate-type flame retardant,

[0199] (d) 5 to 15% of at least one functionalized polyolefin,

[0200] (e) from 1 to 6% in particular between 2 and 4% of at least one plasticizer.

[0201] (f) from 0 to 10%, in particular from 0.1 to 5% of at least one of the additives

[0202] the sum of the constituents (a) to (f) being equal to 100%.

[0203] In another embodiment of this second variant, said composition includes by weight:

[0204] (a) of 30 to 58.9% of at least one semi-crystalline aliphatic polyamide,

[0205] (b) from 15 to 40%, in particular from 15 to 30% of at least one semi-polyamide aromatic,

[0206] (c) 20 to 25% of at least one phosphinate-type flame retardant,

[0207] (d) from 5 to 20%, in particular from 5 to 15% of at least one functionalized polyolefin,

[0208] (e) from 1 to 6% in particular between 2 and 4% of at least one plasticizer.

[0209] (f) 0.1 to 5% of at least one of the additives

[0210] the sum of the constituents (a) to (f) being equal to 100%.

[0211] In a third variant, said composition comprises by weight:

[0212] (a) from 30 to 64%, in particular from 30 to 60% of at least one semi-aliphatic polyamide crystalline,

[0213] (b) from 15 to 40%, in particular from 15 to 30% of at least one semi-polyamide aromatic,

[0214] (c) 15 to 30%, in particular 20 to 25% of at least one type of flame retardant phosphinate,

[0215] (d) of 5 to 15% of at least one functionalized polyolefin,

[0216] (e) from 1 to 6% in particular between 2 and 4% of at least one plasticizer.

[0217] (f) from 0 to 10%, in particular from 0.1 to 5% of at least one of the additives

[0218] the sum of the constituents (a) to (f) being equal to 100%.

[0219] In one embodiment of this third variant, said composition includes by weight:

[0220] (a) from 30 to 64%, in particular from 30 to 60% of at least one semi-aliphatic polyamide crystalline,

[0221] (b) from 15 to 40%, in particular from 15 to 30% of at least one semi-polyamide aromatic,

[0222] (c) 15 to 30%, in particular 20 to 25% of at least one type of flame retardant phosphinate,

[0223] (d) of 5 to 15% of at least one functionalized polyolefin,

[0224] (e) from 1 to 6% in particular between 2 and 4% of at least one plasticizer.

[0225] (f) from 0 to 10%, in particular from 0.1 to 5% of at least one of the additives

[0226] the sum of the constituents (a) to (f) being equal to 100%.

[0227] In another embodiment of this third variant, said composition comprises by weight:

[0228] (a) from 30 to 63.9%, in particular from 30 to 60% of at least one aliphatic polyamide semi-crystalline,

[0229] (b) from 15 to 40%, in particular from 15 to 30% of at least one semi-polyamide aromatic,

[0230] (c) 15 to 30%, in particular 20 to 25% of at least one type of flame retardant phosphinate,

[0231] (d) of 5 to 15% of at least one functionalized polyolefin,

[0232] (e) from 1 to 6% in particular between 2 and 4% of at least one plasticizer.

[0233] (f) 0.1 to 5% of at least one of the additives

[0234] the sum of the constituents (a) to (f) being equal to 100%.

[0235] Advantageously, regardless of the embodiments of these three variants, the present invention covers the same compositions which are made up instead of comprising constituents (a) to (f), the sum of said constituents (a) to (f) being equal to 100%.

[0236] In one embodiment, the above-defined composition has an elongation at break > 50%.

[0237] In another embodiment, the above-defined composition has a yield stress < 20MPa, preferably <17 MPa, more preferably < 14MPa.

[0238] In yet another embodiment, the above-defined composition has a threshold elongation > 3%, preferably > 5%, more preferably > 10%.

[0239] In another embodiment, the above-defined composition has an elongation at break > 50% and a yield stress < 20MPa, preferably < 17 MPa, more preferably < 14MPa.

[0240] In another embodiment, the above-defined composition has an elongation at break > 50% and an elongation at yield > 3%, preferably > 5%, more preferably > 10%.

[0241] In another embodiment, the above-defined composition has an elongation at break > 50%, a yield stress < 20MPa, preferably < 17 MPa, more preferably < 14MPa and a yield stress >3%, preferably >5%, more preferably > 10%.

[0242] Advantageously, said composition exhibits good abrasion resistance as measured according to ISO 9352:2012. Advantageously, the compositions of the invention after coating have an electrical insulating role with a breakdown voltage as measured according to IEC 60243-1.

[0243] Advantageously, the above-defined compositions exhibit high dielectric strength (>5 kV / mm at 90°C) as measured according to IEC 60243-1.

[0244] Advantageously, the compositions defined above have a dielectric strength greater than 40 kV / mm at 23°C, preferably greater than 50 kV / mm

[0245] Advantageously, the above-defined compositions have a comparative tracking index (CTI) > 600V as measured according to IEC60112. This insulation is preserved during accelerated thermal aging up to 150°C.

[0246] Advantageously, the compositions of the invention after coating have an electrical insulating role with a breakdown voltage for a thickness of 500pm >30kV in direct current (DC) and > 15kV in alternating current (AC) and a comparative tracking index (CTI) > 600V.

[0247] Advantageously, the compositions of the invention after coating exhibit a dielectric strength >5 kV / mm at 90°C and a comparative tracking index (CTI) > 600V.

[0248] Advantageously, the compositions of the invention after coating have an electrical insulating role with a dielectric strength at 23°C greater than 40kV / mm, preferably greater than 50kV / mm and a comparative tracking index (CTI) > 600V.

[0249] Said composition of the invention is fire resistant and has a V0 result on the UL94 fire test with a thickness of 0.8 mm). Regarding PEBA that may be excluded

[0250] In one embodiment, said composition is devoid of polyether block amides (PEBA).

[0251] Poly ether block amide (PEBA) are copolymers with amide motifs (Bal) and polyether motifs (Ba2), said amide motif (Bal) corresponding to an aliphatic repeating motif selected from a motif obtained from at least one amino acid or a motif obtained from at least one lactam, or an XY motif obtained from polycondensation:

[0252] - of at least one diamine, said diamine being chosen from an aliphatic diamine linear or branched, or an aromatic diamine, or a mixture thereof, and

[0253] - of at least one dicarboxylic acid, said diacid being chosen from a diacid ali phatic or an aromatic diacid,

[0254] said polyether motifs (Ba2) being in particular derived from at least one polyalkylene ether polyol, in particular a polyalkylene ether diol.

[0255] Regarding reinforcing fibres that may be excluded.

[0256] In one embodiment, the reinforcing fibers, said composition is devoid of reinforcing fibers selected from glass fibers, carbon fibers, basalt fibers and basalt-based fibers.

[0257] In another embodiment, said composition is devoid of reinforcing fibers selected from reinforcing fibers of mineral, organic or vegetable origin.

[0258] Examples of mineral fibers include carbon fibers, glass fibers, basalt fibers or basalt-based fibers, silica fibers, and silicon carbide fibers. Examples of organic fibers include Examples include thermoplastic or thermosetting polymer-based fibers, such as semi-aromatic polyamide fibers, aramid fibers, or polyolefin fibers. Among plant-based fibers, natural fibers such as flax, hemp, lignin, bamboo, silk (particularly spider silk), sisal, and other cellulosic fibers, especially viscose, can be cited.

[0259] According to another aspect, the present invention relates to the use of a composition as defined above, to coat, insulate and fireproof an electric battery interconnect bar.

[0260] All the characteristics defined above are valid for this use.

[0261] The composition of the invention makes it possible to cover the interconnecting bar with a thin layer of 0.1 mm to 2 mm, in particular 0.2 mm to 1 mm, especially 0.3 mm to 0.8 mm, more particularly 0.4 mm to 0.6 mm while maintaining a high level of flexibility to accommodate the deformation of the interconnecting bar.

[0262] A material that is too rigid forms cracks or "waves" which are unacceptable for the application.

[0263] In one embodiment, said interconnecting bar is located inside and / or outside electric batteries, in particular electric vehicle batteries, in particular motor vehicle batteries.

[0264] According to yet another aspect, the present invention relates to a method for preparing a coated, insulated and flame-retardant electric battery interconnect bar comprising a step of extruding a composition as defined above onto an electric battery interconnect bar, or a step of powder coating said composition onto an electric battery interconnect bar.

[0265] All the characteristics defined above are valid for the process.

[0266] In one embodiment, said interconnecting bar is located inside and / or outside electric batteries, in particular electric vehicle batteries, in particular motor vehicle batteries.

[0267] The present invention will now be illustrated by non-limiting examples of the scope of the invention.

[0268] EXAMPLES

[0269] The compositions in Table 1 were prepared by mixing the polymer granules in a molten state with the flame retardants and additives. This mixing was carried out by compounding on a 40 mm diameter co-rotating twin-screw extruder with a flat temperature profile (T°) at 250°C. The screw speed was 300 rpm and the throughput was 70 kg / h.

[0270] The polyamide(s), polyolefins, and additives are introduced during the compounding process in the main hopper. The flame retardant is added to the polymer The molten polymer is fed into the middle of the screw via a lateral feeder. If a plasticizer is present, it is also introduced into the molten polymer via a pump.

[0271] The compositions were then extruded as 0.8 mm films by cast extrusion at a speed of Im / min and with temperature settings of 230°C for the extruder and 65°C for the cylinders on which the film is recovered in order to study the mechanical properties and fire resistance according to the standards below.

[0272] The samples tested are die-cut from this film.

[0273] Elongation and yield stress and breakage were measured at 23°C according to ISO 527-1:2012 on a dry sample, dumbbell cut from the 0.8mm thick film.

[0274] The machine used is of type INSTRON 5966. The speed of the crosshead is 50 mm / min.

[0275] The test conditions are 23°C + / - 2°C, on dry samples.

[0276] The compositions of the invention and comparatives were tested with a commonly used flame propagation test called UL94 according to standard NFT 51072 and carried out in test pieces of thickness 0.8 mm.

[0277] [Tables 1] Example of the invention (El) or comparison (EC) EC1 eu EI2 EC2 EC3 EC4 EC5 EC6 PAU 43.4 44 41 46 41 36 41 54 MXD10 20 20 20 20 20 10 20 Lotader® 4700 5 5 5 5 5 5 5 - Lotader® AX8900 2.5 2.5 2.5 2.5 2.5 2.5 2.5 - Escor® 5000 2.5 2.5 2.5 2.5 2.5 2.5 2.5 - Exolit® OP1311 25 25 25 - - - 25 25 Melapur MC25 - - 20 25 30 - - BBSA - 3 3 3 3 3 - Lowinox 44B25 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 Alkanox 240 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 UL94 Fire Test Observation: Creep and flaming droplets Flame persistence < 10s Flame persistence < 10s Complete combustion Complete combustion Complete combustion Creep and flaming droplets Flame persistence < 10s Classification V-2 V-0 V-0 NC NC NC V-2 VO Tension Test @ 23°C 50 mm / min Elongation at Threshold (%) 4.3 3.6 12.4 5.3 5.1 2.5 3.9 2.7 Stress at Threshold (MPa) 20.4 18.1 13.0 28.0 27.0 19.0 19.1 23 Elongation at Break (%) 37 57 105 29 19 18 43 34 Stress at Break (MPa) 20.0 17.7 13.0 23.0 23.0 17.0 18.8 21.8

[0278] The dielectric strength of the alloy according to the EU invention was measured at 12 kV at 90°C, exceeding the target of 5 kV. The invention therefore also meets the electrical insulation requirement.

[0279] NC: Unclassified

[0280] PA11 is an Arkema PAU with a viscosity of 1.35.

[0281] MXD10 is an Arkema PA with a viscosity of 0.9 resulting from the polycondensation of m- xylene diamine and sebacic acid.

[0282] Exolit® OP1311 is a Clariant product (aluminum diethyl phosphinate-based flame retardant).

[0283] BBSA (benzyl butyl sulfonamide)

[0284] Lotader AX8900: ethylene, methyl acrylate and glycidyl methacrylate copolymer (Et / MA / GMA - 68 / 24 / 8 by weight) (SK functional polymer).

[0285] Lotader 4700: copolymer of ethylene, ethyl acrylate and maleic anhydride (Et / EA / MAH - 69 / 30 / 1 by weight) (SK functional polymer).

[0286] Escor® 5000: acrylic acid and ethylene copolymer (Exxon Mobil Chemicals)

[0287] Lowinox® 44B25 (CAS No.: 85-60-9), phenolic primary antioxidant.

[0288] Alkanox® 240 (CAS No.: 31570-04-4), secondary antioxidant phopite (Bren

[0289] Melapur® MC25: flame retardant based on melamine cyanurate (BASF)

[0290] Table 1 above shows that the compositions of the invention EU and EI2 have a V0 result on the UL94 test unlike the comparative composition EC1 which does not have MXD10 or the comparative composition EC5 which has an amount of MXD10 less than 15%.

[0291] Moreover, only the compositions of the invention exhibit an elongation at break > 50% unlike the comparative composition EC1 which does not contain MXD10 or the comparative composition EC5 which contains less than 15% MXD10 or the composition EC6 which does not contain polyolefins or the comparative compositions EC2 to 4 which contain more than 15% MXD10 but whose flame retardant is not of the phosphinate type.

[0292] The compositions of the invention also exhibit a yield strength < 20 MPa and a yield elongation > 3%, unlike EC6 which does not contain polyolefins

Claims

Demands

1. An insulating and flame-retardant composition for covering an electric battery interconnecting busbar comprising by weight: (a) 30 to 65%, in particular 30 to 63.9%, in particular 30 to 60%, of at least one semi-crystalline aliphatic polyamide, (b) 15 to 40%, in particular 15 to 30%, of at least one semi-aromatic polyamide, said at least one semi-aromatic polyamide having the formula A / XT in which A is selected from a motif obtained from an amino acid, a motif obtained from a lactam, and a motif conforming to the formula (Ca diamine)(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, advantageously between 9 and 18, the motif (Ca diamine)(Cb diacid) Ca) being chosen from among the aliphatic diamines, linear or branched,cycloaliphatic diamines and alkylaro-matic diamines and the motif (Cb diacid) being chosen from aliphatic diacids, linear or branched, and cycloaliphatic diacids; XT designates a motif obtained from the polycondensation of a Cx diamine and terephthalic acid, with x representing the number of carbon atoms of the Cx diamine, x being between 5 and 36, advantageously between 9 and 18, or said at least one semi-aromatic polyamide being a polyamide of formula XiY, XiY being a repeating motif obtained from the polycondensation of a diamine (Xi) selected from an arylamine, and at least one dicarboxylic acid selected from adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid, and diacids obtained from fatty acids,(c) 15 to 30%, in particular 20 to 25% of at least one phosphinate-type flame retardant, (d) 5 to 20%, in particular 5 to 15% of at least one functionalized polyolefin, (e) 0 to 6%, in particular 1 to 6%, notably between 2 and 4% of at least one plasticizer. (f) from 0 to 10%, in particular from 0.1 to 5% of at least one of the additives, the sum of the constituents (a) to (f) being equal to 100%.

2. Composition according to claim 1, characterized in that the polyamide is a long-chain polyamide having a number of carbons per nitrogen atom greater than or equal to 8, in particular greater than or equal to 9, in particular greater than or equal to 10.

3. Composition according to claim 2, characterized in that said long chain polyamide is selected from PA610, PA612, PA1010, PA1012, PAU and PA12.

4. Composition according to claim 1 or 2, characterized in that said at least one semi-crystalline aliphatic polyamide is selected from PA1010, PA1012, PAU and PA12, in particular from PA11 and PA12, especially PAU.

5. Composition according to any one of claims 1 to 4, characterized in that said semi-aromatic polyamide is a polyamide of formula MXDY in which MXD corresponds to meta-xylylene diamine and Y is an aliphatic dicarboxylic acid in C6 to Cl8, in particular in C9 to Cl8, especially in C9 to C12.

6. Composition according to claim 5, characterized in that said semi-aromatic polyamide of formula MXDY is selected from MXD6, MXD10 and MXD12, in particular MXD10.

7. Composition according to any one of claims 1 to 6, characterized in that the flame retardant is a metal salt selected 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.

8. Composition according to any one of claims 1 to 7, characterized in that the polyolefin is crosslinked.

9. Composition according to any one of claims 1 to 8, characterized in that the additives are selected from antioxidants, colour pigments and flame retardant synergists, in particular nitrogen synergists, especially melamine-based.

10. Composition according to any one of claims 1 to 9, characterized in that it is devoid of polyether block amides (PEBA).

11. Composition according to any one of claims 1 to 10, characterized in that it is devoid of reinforcing fibers.

12. Use of a composition as defined in claims 1 to 11, to coat, insulate and fireproof an electric battery interconnect bar.

13. Use according to claim 12, characterized in that said interconnecting bar is located inside and / or outside electric batteries, in particular electric vehicle batteries, in particular motor vehicle batteries.

14. Method of preparing an insulated and flame-retardant coated electric battery interconnect bar comprising an extrusion step of a composition as defined in any one of claims 1 to 11 on an electric battery interconnect bar, or a powder coating step of said composition on an electric battery interconnect bar.