Insulating and flame retardant polyamide composition for covering electric battery interconnect bars - Patents.com

Abstract

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

Description

[Technical field]

[0001] The present invention relates to an insulating and flame retardant polyamide composition for covering electric battery busbars. [Background technology]

[0002] In the field of electric vehicles, connectors called busbars (interconnect bars) are present to circulate high currents in and out of the battery. These bars must be protected with an insulating coating that resists mechanical stress and ageing. Given the consequences of a fire occurring in this environment, the coating must also exhibit good fire resistance.

[0003] There are many processes for manufacturing busbars. The main one is to extrude a polymer around a central copper strip. This structure is then cut and bent (at ambient temperature) to take the shape required for placement on the vehicle. For the most complex busbar shapes, specific grades of powder coating can also be used.

[0004] The technical problem associated with battery busbar applications is to produce 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 busbar. When bent, a material that is too stiff will crack on the outer surface and form "waves" or "beads" on the inner surface, which is unacceptable for the application.

[0005] Therefore, the plastic threshold behavior of a material is very important: a low threshold stress and a large threshold elongation are desirable.

[0006] Although the deformation levels of these coatings remain low, the materials still need to have an elongation at break of greater than 50%. Good abrasion resistance is also necessary for this application.

[0007] The coating must also act as an electrical insulator, which translates into properties such as breakdown voltage, dielectric strength, and a comparative tracking index (CTI) of greater than 600 V. This insulating property must be maintained even during accelerated thermal aging up to 150°C.

[0008] Finally, the rheological properties of the alloy must be compatible with the extrusion of thin polymer layers, on the order of 0.5 mm.

[0009] The flame retardants most frequently used in polyamide (PA) compositions are flame retardants of the phosphinate class. Their mode of action and thermal stability make them particularly suitable for polyamide matrices. Thus, US 2006 / 0084734 A1 describes phosphinate flame retardants and their preparation, and US 2005 / 0014874 A1 describes the use of these phosphinates in the flame retardation of aromatic or semi-aromatic polyamides. This patent application provides information on the superior fire resistance of semi-aromatic polyamides (PAP) compared to aliphatic PA in the presence of phosphinate flame retardants.

[0010] Furthermore, EP 1 741 753 A1 describes the composition of this type of flame retardant in a mixture of aliphatic and semi-aromatic PA in the presence of inorganic reinforcement (glass fibres), in which the phosphinate-based flame retardant is necessarily combined with a melamine-based nitrogen synergist.

[0011] Finally, in the rail sector, US 2017 / 0037198 A1 presents formulations based on plasticized and phosphinate flame retardant PA12, optionally with the addition of polyolefin and / or PEBA impact modifiers.

[0012] Nevertheless, in these various documents information is given on how to obtain fire-resistant or ductile PA. However, it is difficult to obtain a thin-walled product that is both ductile and fire-resistant. In the cited prior art, only the formulations containing glass fibres have L94 V0 at 0.8 mm. The alloys without glass fibres have UL94 even at higher thicknesses. However, the smaller the thickness, the more difficult the fire resistance becomes.

[0013] Furthermore, the prior art does not provide any information regarding combinations within a formulation to simultaneously achieve the flexibility and fire resistance required for battery busbar applications. Summary of the Invention

[0014] Thus, the present invention provides a composition comprising, by weight: (a) 30 to 65%, more particularly 30 to 63.9%, in particular 30 to 60%, of at least one semicrystalline aliphatic polyamide; (b) 15 to 40%, in particular 15 to 30%, of at least one semi-aromatic polyamide, (c) 15-30%, more specifically 20-25%, of at least one phosphinate-based flame retardant; (d) 5 to 20%, more specifically 5 to 15%, of at least one functionalized polyolefin; (e) 0-6%, more particularly 1-6%, in particular between 2 and 4%, of at least one plasticizer; (f) 0 to 10%, more specifically 0.1 to 5%, of at least one additive Including, The total of components (a) to (f) is 100%. The present invention relates to a flame retardant insulating composition for covering electric battery bus bars.

[0015] Thus, the inventors have discovered that a mixture of semi-crystalline aliphatic and semi-aromatic polyamides in specific proportions, in combination with similarly specific proportions of phosphinate-based flame retardants and functionalized polyolefins, and optionally plasticizers and additives, can provide a composition exhibiting the above criteria required for battery busbar applications.

[0016] Coating the busbars with the composition of the invention makes it possible to protect the busbars with an insulating coating that is fire resistant and resistant to mechanical stress and deterioration.

[0017] The busbars are arranged inside and / or outside an electric battery, more particularly an electric battery of a vehicle, in particular an automobile. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Semicrystalline aliphatic polyamide (a) The at least one semi-crystalline aliphatic polyamide (a) is present in the composition in an amount by weight of 30 to 65%, more particularly 30 to 63.9%, in particular 30 to 60%.

[0019] Semicrystalline polyamide is understood to mean a material which is generally solid at room temperature, which softens upon increasing temperature, more specifically above the glass transition temperature (Tg), which can melt rapidly above the so-called melting point (Tm), and which becomes solid again when the temperature falls below the crystallization temperature.

[0020] Tg, Tc and Tm are determined by differential scanning calorimetry (DSC) according to standards 11357-2:2013 and 11357-3:2013, respectively.

[0021] The number-average molecular weight Mn of said semicrystalline polyamide is preferably in the range from 10,000 to 85,000, in particular from 10,000 to 60,000, preferably from 10,000 to 50,000 and even more preferably from 12,000 to 50,000. These Mn values ​​may correspond to an intrinsic viscosity of 0.8 or more, measured in m-cresol according to ISO standard 307:2007, but with a changed solvent (m-cresol instead of sulfuric acid, temperature of 20° C.).

[0022] The nomenclature used to define polyamides is described in ISO standard 1874-1:2011 “Plastics - Polyamide (PA) moulding and extrusion materials - Part 1: Designation”, in particular page 3 (Tables 1 and 2), and is well known to the skilled person.

[0023] The term polyamide includes both homopolyamides and copolyamides.

[0024] The at least one aliphatic semicrystalline polyamide results 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 from mixtures thereof.

[0025] When said at least one aliphatic semicrystalline polyamide results from the polycondensation of at least one lactam, said at least one lactam can be chosen from C8 to C18, preferably C10 to C18 and more preferably C10 to C12 lactams, which are in particular decanolactam, undecanolactam and lauryllactam.

[0026] When said at least one aliphatic semicrystalline polyamide results from the polycondensation of at least one lactam, it may comprise a single lactam or several lactams.

[0027] Advantageously, said at least one aliphatic semicrystalline polyamide results from the polycondensation of a single lactam, said lactam being chosen from lauryllactam and undecanolactam, advantageously lauryllactam.

[0028] When said at least one aliphatic semi-crystalline polyamide results from the polycondensation of at least one amino acid, said at least one amino acid may be selected from C8 to C18, preferably C10 to C18, more preferably C10 to C12 amino acids.

[0029] C8-C18 amino acids are in particular 9-aminononanoic acid, 10-aminodecanoic acid, 10-aminoundecanoic acid, 12-aminododecanoic acid and 11-aminoundecanoic acid, and derivatives thereof, in particular N-heptyl-11-aminoundecanoic acid.

[0030] Thus, when said at least one aliphatic semicrystalline polyamide results from the polycondensation of at least one amino acid, it may comprise a single amino acid or several amino acids.

[0031] Advantageously, said aliphatic semicrystalline polyamide results from the polycondensation of a single amino acid, said amino acid being chosen from 10-aminodecanoic acid, 11-aminoundecanoic acid and 12-aminododecanoic acid, advantageously 11-aminoundecanoic acid.

[0032] When said at least one aliphatic semi-crystalline polyamide is obtained from the polycondensation of at least one diamine X from C6 to C36, preferably from C6 to C18, preferably from C6 to C12, more preferably from C10 to C12, with at least one diacid Y from C6 to C36, preferably from C6 to C18, preferably from C6 to C12, more preferably from C10 to C12, said at least one diamine X is an aliphatic diamine and said at least one diacid Y is an aliphatic diacid.

[0033] The diamines may be linear or branched, preferably linear.

[0034] The at least one C6 to C36 diamine X may be chosen in particular 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, octadecenediamine, eicosanediamine, docosanediamine, and diamines derived from fatty acids.

[0035] Advantageously, said at least one diamine X is C6 to C18 and is chosen 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.

[0036] Advantageously, said at least one C6 to C12 diamine X is chosen in particular from 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine and 1,12-dodecamethylenediamine.

[0037] Advantageously, said at least one C6 to C12 diamine X is chosen in particular from 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine and 1,12-dodecamethylenediamine.

[0038] Advantageously, the diamine X used is a C10-C12 diamine and is in particular chosen from 1,10-decamethylenediamine, 1,11-undecamethylenediamine and 1,12-dodecamethylenediamine.

[0039] The at least one C6-C36 dicarboxylic acid Y can 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 derived from fatty acids.

[0040] The diacids may be linear or branched, preferably linear.

[0041] Advantageously, said at least one dicarboxylic acid Y is C6 to C18 and is chosen from adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid and octadecanedioic acid.

[0042] Advantageously, said at least one dicarboxylic acid Y is C6 to C12 and is chosen from adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid and dodecanedioic acid.

[0043] Advantageously, said at least one dicarboxylic acid Y is C10 to C12 and is chosen from sebacic acid, undecanedioic acid and dodecanedioic acid.

[0044] When said aliphatic semicrystalline polyamide results from the polycondensation of at least one diamine X with at least one dicarboxylic acid Y, it may comprise a single diamine or multiple diamines as well as a single dicarboxylic acid or multiple dicarboxylic acids.

[0045] Advantageously, said aliphatic semicrystalline polyamide results from the polycondensation of a single diamine X with a single dicarboxylic acid Y.

[0046] In one embodiment, said at least one polyamide is a long chain polyamide having a number of carbons per nitrogen atom of 8 or more, more particularly 9 or more, especially 10 or more.

[0047] In another embodiment, the at least one semi-crystalline aliphatic polyamide is selected from polyamides PA610, PA612, PA1010, PA1012, PA11, and PA12.

[0048] Advantageously, said at least one semicrystalline aliphatic polyamide is chosen from the polyamides PA1010, PA1012, PA11 and PA12, more particularly PA11 and PA12, and in particular PA11.

[0049] Semi-aromatic polyamide (b) Said at least one semi-aromatic polyamide (b) is present in the composition in an amount by weight ranging from 15 to 40%, more particularly from 15 to 30%.

[0050] 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 EP 1 505 099 A1, in particular a semi-aromatic polyamide of formula A / XT, in which A is selected from units resulting from amino acids, units resulting from lactams and units of formula (Ca diamine).(Cb diacid), in which a is the number of carbon atoms of the diamine and b is the number of carbon atoms of the diacid, a and b are each between 4 and 36, advantageously between 9 and 18, the (Ca diamine) units being selected from linear or branched aliphatic diamines, cycloaliphatic diamines and alkylaromatic diamines, and the (Cb diacid) units being selected from linear or branched aliphatic diacids, cycloaliphatic diacids and aromatic diacids;

[0051] XT represents units resulting from the polycondensation of a Cx diamine with terephthalic acid, x representing the number of carbon atoms of the Cx diamine, x being between 5 and 36, advantageously between 9 and 18, in particular polyamides of formula A / 5T, A / 6T, A / 9T, A / 10T or A / 11T, A being as defined above, more particularly 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, PA The polyamide is selected from 11 / MXDT / 10T, or 11 / 5T / 10T.

[0052] In particular, the semi-crystalline, semi-aromatic polyamide is selected from polyamides 11 / 5T or 11 / 6T or 11 / 10T, MXDT / 10T, MPMDT / 10T, and BACT / 10T.

[0053] T corresponds to terephthalic acid, MXD corresponds to m-xylylenediamine, MPMD corresponds to methylpentamethylenediamine, and BAC corresponds to bis(aminomethyl)cyclohexane.

[0054] In one embodiment, the Cb diacids of units A do not include itaconic acid.

[0055] In another embodiment, said at least one semi-aromatic polyamide is a polyamide of formula X1Y, X1Y, whose repeating units result from the polycondensation of a diamine (X1) selected from arylamines and at least one aliphatic dicarboxylic acid (Y) as defined above.

[0056] In one embodiment, the aliphatic dicarboxylic acid (Y) of the semi-aromatic polyamide of formula X1Y does not include itaconic acid.

[0057] Advantageously, in this embodiment, the arylamine is chosen from m-xylylenediamine (MXD, CAS number: 1477-55-0) or p-xylylenediamine (PXD, CAS number: 539-48-0).

[0058] In another embodiment, the at least one semi-aromatic polyamide is a polyamide of formula MXDY, where MXD corresponds to m-xylylenediamine and Y is C6-C18.

[0059] Advantageously, said semi-aromatic polyamide of formula MXDY is chosen from MXD6, MXD10 and MXD12, and more particularly is MXD10.

[0060] In one embodiment, the semi-aromatic polyamide does not contain any 2-pyrrolidone units.

[0061] Phosphinate flame retardants (c) The at least one phosphinate flame retardant (c) is present in the composition at 15 to 30%, more particularly 20 to 25%, by weight.

[0062] The flame retardant is in particular a metal salt selected from metal salts of phosphinic acids, metal salts of diphosphinic acids, polymers comprising at least one metal salt of phosphinic acids and polymers comprising at least one metal salt of diphosphinic acids. The flame retardant may also be a mixture of the aforementioned flame retardants.

[0063] The flame retardant may also be selected from the metal salts of phosphinic acids of formula (I) and the metal salts of diphosphinic acids of formula (II): TIFF2024543172000001.tif32170TIFF2024543172000002.tif34170[In the formula, R1 and R2 each independently represent a linear or branched C1-C6 alkyl group or an aryl group; R3 is a linear or branched C1 to C10 alkylene, C6 to C10 arylene, C6 to C10 alkylarylene, or C6 to C10 arylalkylene group; M is Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, or K ions and / or protonated amine bases; m represents an integer of 1 to 4; n represents an integer of 1 to 4; x represents an integer of 1 to 4; n and m are selected so that the salt is neutral, ie, uncharged.

[0064] Preferably, M is a calcium, magnesium, aluminum, or zinc ion.

[0065] Preferably, R1 and R2 independently of one another represent a methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl and / or phenyl group.

[0066] Preferably, R3 is a 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 group.

[0067] Functionalized Polyolefins (d) Said at least one functionalized polyolefin (d) is present in the composition in an amount by weight ranging from 5 to 20%, more particularly from 5 to 15%.

[0068] The functionalized polyolefins may be polymers of alpha-olefins having reactive units (functionalities), such as acid, anhydride or epoxy functions. By way of example, mention may be made of the aforementioned polyolefins (B2) grafted or copolymerized or terpolymerized with unsaturated epoxides, such as glycidyl (meth)acrylate, or with carboxylic acids or corresponding salts or esters, such as (meth)acrylic acid, which can be fully or partially neutralized with metals such as Zn, or with carboxylic anhydrides, such as maleic anhydride. The functionalized polyolefins are, for example, PE / EPR mixtures, the weight ratio of which can vary within a wide range, for example between 40 / 60 and 90 / 10, said mixtures being cografted with anhydrides, in particular maleic anhydride, for example with a grafting degree of 0.01-5% by weight.

[0069] The functionalized polyolefins can be chosen from the following (co)polymers grafted with maleic anhydride or glycidyl methacrylate, with a degree of grafting ranging for example from 0.01 to 5% by weight: PE, PP, for example copolymers of ethylene with propylene, butene, hexene or octene, containing from 35 to 80% by weight of ethylene; - Ethylene / alpha-olefins, such as ethylene / propylene, EPR (short for ethylene-propylene-rubber), and ethylene / propylene / diene (EPDM) copolymers; - styrene / ethylene-butene / styrene (SEBS), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS) and styrene / ethylene-propylene / styrene (SEPS) block copolymers; - copolymers of ethylene and up to 40% by weight of vinyl acetate (EVA); - copolymers of ethylene and alkyl (meth)acrylates containing up to 40% by weight of alkyl (meth)acrylates; - Copolymers of ethylene with vinyl acetate (EVA) and alkyl (meth)acrylates containing up to 40% by weight of a comonomer.

[0070] The functionalized polyolefin may also be selected from propylene-based ethylene / propylene copolymers grafted with maleic anhydride and then condensed with a monoaminated polyamide (or polyamide oligomer) (products described in EP-A-0 342 066).

[0071] The functionalized polyolefin may also be a copolymer or terpolymer of at least the following units: (1) ethylene, (2) an alkyl (meth)acrylate, or a saturated carboxylic acid vinyl ester, and (3) an anhydride, such as maleic or (meth)acrylic anhydride, or an epoxy, such as glycidyl (meth)acrylate.

[0072] Examples of the latter type of functionalized polyolefins include the following copolymers: - ethylene / alkyl (meth)acrylate / (meth)acrylic acid or maleic anhydride or glycidyl methacrylate copolymers; - ethylene / vinyl acetate / maleic anhydride or glycidyl methacrylate copolymers; - Ethylene / vinyl acetate or alkyl (meth)acrylate / (meth)acrylic acid or maleic anhydride or glycidyl methacrylate copolymer where ethylene preferably represents at least 60% by weight and the termonomer (its functionality) represents, for example, 0.1 to 10% by weight of the copolymer.

[0073] In the above copolymers, the (meth)acrylic acid can be salified with Zn or Li.

[0074] The term "alkyl (meth)acrylate" refers to C1 to C8 alkyl methacrylates and alkyl acrylates, and may be selected from methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, methyl methacrylate, and ethyl methacrylate.

[0075] Additionally, the above functionalized polyolefins may also be crosslinked by any suitable process or agent (diepoxy, diacid, peroxide, etc.); the term functionalized polyolefin also includes mixtures of the above polyolefins with difunctional agents such as diacids, dianhydrides, diepoxy, etc. that can react therewith, or mixtures of at least two functionalized polyolefins that can react with each other.

[0076] The above copolymers may be randomly or sequentially copolymerized and may have a linear or branched chain structure.

[0077] The molecular weight, MFI index, and density of these polyolefins can also vary within wide limits that will be appreciated by those skilled in the art. MFI is an abbreviation for Melt Flow Index. It is measured according to ASTM standard 1238.

[0078] In one embodiment, the polyolefin is crosslinked.

[0079] Plasticizer (e) Said at least one plasticizer (e) may be present in the composition in an amount by weight of 0 to 6%, more particularly 1 to 6%, in particular between 2 and 4%.

[0080] The plasticizer may be any plasticizer commonly used in compositions based on polyamide(s).

[0081] Advantageously, plasticizers are used that exhibit good thermal stability so that no smoke is formed during the steps of mixing the various polymers and converting the resulting composition.

[0082] In particular, this plasticizer can be chosen from: benzenesulfonamide derivatives, such as n-butylbenzenesulfonamide (BBSA), the ortho and para isomers of ethyltoluenesulfonamide (ETSA), N-cyclohexyltoluenesulfonamide, and N-(2-hydroxypropyl)benzenesulfonamide (HP-BSA); Esters of hydroxybenzoic acid, such as 2-ethylhexyl p-hydroxybenzoate (EHPB) and 2-decylhexyl p-hydroxybenzoate (HDPB); Esters or ethers of tetrahydrofurfuryl alcohol, such as oligoethyleneoxy-tetrahydrofurfuryl alcohol, and Esters of citric acid or hydroxymalonic acid, for example oligoethyleneoxymalonate.

[0083] A preferred plasticizer is n-butylbenzenesulfonamide (BBSA).

[0084] Another particularly preferred plasticizer is N-(2-hydroxypropyl)benzenesulfonamide (HP-BSA), since the latter exhibits the advantage of preventing the formation of deposits in the extrusion screw and / or die during the deformation stage by extrusion ("die roll").

[0085] Obviously, mixtures of plasticizers may be used.

[0086] Additives (f) Said at least one additive (f) may be present in the composition at 0 to 10%, more particularly 0.1 to 5%, by weight.

[0087] The at least one additive may be selected from stabilizers, dyes, conversion assisting adjuvants (processing aids), surfactants, nucleating agents, pigments, gloss agents, antioxidants, lubricants, waxes, flame retardant synergists, or mixtures thereof.

[0088] By way of example, the stabilizer can be a UV stabilizer, an organic stabilizer, or more generally a combination of organic stabilizers, such as, for example, phenolic antioxidants (such as, for example, types such as Irganox® 245 or 1098 or 1010 by Ciba-BASF), or phosphite antioxidants (such as, for example, Irgafos® 126 or Irgafos® 168 by Ciba-BASF), and optionally other stabilizers, such as, for example, HALS, which stands for hindered amine light stabilizers (such as, for example, Tinuvin® 770 by Ciba-BASF), UV inhibitors (such as, for example, Tinuvin® 312 by Ciba), or phosphorus stabilizers. It is also possible to use amine-type antioxidants, such as Naugard® 445 by Crompton, or multifunctional stabilizers, such as Nylostab® S-EED by Clariant.

[0089] The stabilizer can be a mineral stabilizer, such as a copper-based stabilizer. Examples of such mineral stabilizers include copper acetate and copper halides. It should be noted that other metals, such as silver, may also be considered, but are known to be less effective. These copper-based compounds are typically combined with alkali metal halides, particularly potassium halides.

[0090] Flame retardant synergists are described, inter alia, in WO2005121234.

[0091] They may be selected from nitrogen synergists and phosphorus / nitrogen synergists.

[0092] Nitrogen synergists preferably include benzoguanamine, tris(hydroxyethyl)isocyanurate, allantoin, glycoluril, melamine, melamine cyanurate, dicyandiamide, guanidine, and carbodiimide.

[0093] The nitrogen synergist preferably comprises a melamine condensation product, for example melem, melam or melon, or highly condensed compounds of this type, or mixtures thereof, which can be prepared, for example, by the process described in US Pat. No. 5,985,960.

[0094] The phosphorus / nitrogen synergist may comprise a reaction product of melamine with phosphoric acid or condensed phosphoric acids, or may comprise a reaction product of a melamine condensation product with phosphoric acid or condensed phosphoric acids, or may comprise a mixture of the specified products.

[0095] In one embodiment, the additives are selected from antioxidants, color pigments, and flame retardant synergists, particularly nitrogen synergists, and more particularly melamine-based synergists.

[0096] composition The flame retardant insulating composition for covering an electric battery busbar comprises, by weight: (a) 30 to 65%, more particularly 30 to 63.9%, in particular 30 to 60%, of at least one semicrystalline aliphatic polyamide; (b) 15 to 40%, more specifically 15 to 30%, of at least one semi-aromatic polyamide; (c) 15-30%, more specifically 20-25%, of at least one phosphinate-based flame retardant; (d) 5 to 20%, more specifically 5 to 15%, of at least one functionalized polyolefin; (e) 0-6%, more particularly 1-6%, in particular 2-4%, of at least one plasticizer; (f) 0 to 10%, more specifically 0.1 to 5%, of at least one additive Including, The sum of components (a) to (f) is 100%.

[0097] Advantageously, said insulating and flame retardant composition for covering electric battery busbars comprises, by weight: (a) 30 to 65%, more particularly 30 to 63.9%, in particular 30 to 60%, of at least one semicrystalline aliphatic polyamide; (b) 15 to 40%, more specifically 15 to 30%, of at least one semi-aromatic polyamide; (c) 15-30%, more specifically 20-25%, of at least one phosphinate-based flame retardant; (d) 5 to 20%, more specifically 5 to 15%, of at least one functionalized polyolefin; (e) 0-6%, more particularly 1-6%, in particular 2-4%, of at least one plasticizer; (f) 0 to 10%, more specifically 0.1 to 5%, of at least one additive It consists of: The sum of components (a) to (f) is 100%.

[0098] In a first variant, the composition comprises, by weight: (a) 30 to 64%, in particular 30 to 60%, of at least one semicrystalline aliphatic polyamide, (b) 15 to 40%, more specifically 15 to 30%, of at least one semi-aromatic polyamide; (c) 15-30%, more specifically 20-25%, of at least one phosphinate-based flame retardant; (d) 5 to 20%, more specifically 5 to 15%, of at least one functionalized polyolefin; (e) between 1 and 6%, in particular between 2 and 4%, of at least one plasticizer; (f) 0 to 10%, more specifically 0.1 to 5%, of at least one additive Including, The sum of components (a) to (f) is 100%.

[0099] In one embodiment of this first variant, the composition comprises, by weight: (a) 30 to 64%, in particular 30 to 60%, of at least one semicrystalline aliphatic polyamide, (b) 15 to 30% of at least one semi-aromatic polyamide; (c) 15-30%, more specifically 20-25%, of at least one phosphinate-based flame retardant; (d) 5 to 20%, more specifically 5 to 15%, of at least one functionalized polyolefin; (e) between 1 and 6%, in particular between 2 and 4%, of at least one plasticizer; (f) 0 to 10%, more specifically 0.1 to 5%, of at least one additive Including, The sum of components (a) to (f) is 100%.

[0100] Advantageously, the composition comprises, by weight: (a) 30 to 59% of at least one semicrystalline aliphatic polyamide; (b) 15 to 30% of at least one semi-aromatic polyamide; (c) 20-25% of at least one phosphinate-based flame retardant; (d) 5 to 20%, more specifically 5 to 15%, of at least one functionalized polyolefin; (e) between 1 and 6%, in particular between 2 and 4%, of at least one plasticizer; (f) 0 to 10%, more specifically 0.1 to 5%, of at least one additive Including, The sum of components (a) to (f) is 100%.

[0101] More preferably, the composition comprises, by weight: (a) 30 to 64%, in particular 30 to 60%, of at least one semicrystalline aliphatic polyamide, (b) 15 to 30% of at least one semi-aromatic polyamide; (c) 15-30%, more specifically 20-25%, of at least one phosphinate-based flame retardant; (d) 5 to 15% of at least one functionalized polyolefin; (e) between 1 and 6%, in particular between 2 and 4%, of at least one plasticizer; (f) 0 to 10%, more specifically 0.1 to 5%, of at least one additive Including, The sum of components (a) to (f) is 100%.

[0102] Even more advantageously, the composition comprises, by weight: (a) 30 to 59% of at least one semicrystalline aliphatic polyamide; (b) 15 to 30% of at least one semi-aromatic polyamide; (c) 20-25% of at least one phosphinate-based flame retardant; (d) 5 to 15% of at least one functionalized polyolefin; (e) between 1 and 6%, in particular between 2 and 4%, of at least one plasticizer; (f) 0 to 10%, more specifically 0.1 to 5%, of at least one additive Including, The sum of components (a) to (f) is 100%.

[0103] Even more advantageously, the composition comprises, by weight: (a) 30 to 58.9 percent of at least one semicrystalline aliphatic polyamide; (b) 15 to 30% of at least one semi-aromatic polyamide; (c) 20-25% of at least one phosphinate-based flame retardant; (d) 5 to 15% of at least one functionalized polyolefin; (e) between 1 and 6%, in particular between 2 and 4%, of at least one plasticizer; (f) 0.1 to 5% of at least one additive Including, The sum of components (a) to (f) is 100%.

[0104] In a second variant, the composition comprises, by weight: (a) 30 to 59% of at least one semicrystalline aliphatic polyamide; (b) 15 to 40%, more specifically 15 to 30%, of at least one semi-aromatic polyamide; (c) 20-25% of at least one phosphinate-based flame retardant; (d) 5 to 20%, more specifically 5 to 15%, of at least one functionalized polyolefin; (e) between 1 and 6%, in particular between 2 and 4%, of at least one plasticizer; (f) 0 to 10%, more specifically 0.1 to 5%, of at least one additive Including, The sum of components (a) to (f) is 100%.

[0105] In one embodiment of this second variant, the composition comprises, by weight: (a) 30 to 59% of at least one semicrystalline aliphatic polyamide; (b) 15 to 40%, more specifically 15 to 30%, of at least one semi-aromatic polyamide; (c) 20-25% of at least one phosphinate-based flame retardant; (d) 5 to 15% of at least one functionalized polyolefin; (e) between 1 and 6%, in particular between 2 and 4%, of at least one plasticizer; (f) 0 to 10%, more specifically 0.1 to 5%, of at least one additive Including, The sum of components (a) to (f) is 100%.

[0106] In another embodiment of this second variant, the composition comprises, by weight: (a) 30 to 58.9 percent of at least one semicrystalline aliphatic polyamide; (b) 15 to 40%, more specifically 15 to 30%, of at least one semi-aromatic polyamide; (c) 20-25% of at least one phosphinate-based flame retardant; (d) 5 to 20%, more specifically 5 to 15%, of at least one functionalized polyolefin; (e) between 1 and 6%, in particular between 2 and 4%, of at least one plasticizer; (f) 0.1 to 5% of at least one additive Including, The sum of components (a) to (f) is 100%.

[0107] In a third variant, the composition comprises, by weight: (a) 30 to 64%, in particular 30 to 60%, of at least one semicrystalline aliphatic polyamide, (b) 15 to 40%, more specifically 15 to 30%, of at least one semi-aromatic polyamide; (c) 15-30%, more specifically 20-25%, of at least one phosphinate-based flame retardant; (d) 5 to 15% of at least one functionalized polyolefin; (e) between 1 and 6%, in particular between 2 and 4%, of at least one plasticizer; (f) 0 to 10%, more specifically 0.1 to 5%, of at least one additive Including, The sum of components (a) to (f) is 100%.

[0108] In one embodiment of this third variant, the composition comprises, by weight: (a) 30 to 64%, in particular 30 to 60%, of at least one semicrystalline aliphatic polyamide, (b) 15 to 40%, more specifically 15 to 30%, of at least one semi-aromatic polyamide; (c) 15-30%, more specifically 20-25%, of at least one phosphinate-based flame retardant; (d) 5 to 15% of at least one functionalized polyolefin; (e) between 1 and 6%, in particular between 2 and 4%, of at least one plasticizer; (f) 0 to 10%, more specifically 0.1 to 5%, of at least one additive Including, The sum of components (a) to (f) is 100%.

[0109] In another embodiment of this third variant, the composition comprises, by weight: (a) 30 to 63.9 percent, in particular 30 to 60 percent, of at least one semicrystalline aliphatic polyamide; (b) 15 to 40%, more specifically 15 to 30%, of at least one semi-aromatic polyamide; (c) 15-30%, more specifically 20-25%, of at least one phosphinate-based flame retardant; (d) 5 to 15% of at least one functionalized polyolefin; (e) between 1 and 6%, in particular between 2 and 4%, of at least one plasticizer; (f) 0.1 to 5% of at least one additive Including, The sum of components (a) to (f) is 100%.

[0110] Advantageously, whatever the embodiment of these three variants, the invention also extends to the same compositions which, instead of comprising components (a) to (f), consist of said components (a) to (f), the sum of which is equal to 100%.

[0111] In one embodiment, the composition defined above has an elongation at break of greater than 50%.

[0112] In another embodiment, the composition as defined above has a stress at threshold of less than 20 MPa, preferably less than 17 MPa, and more preferably less than 14 MPa.

[0113] In yet another embodiment, the composition as defined above has an elongation at the threshold value of more than 3%, preferably more than 5%, and even more preferably more than 10%.

[0114] In another embodiment, the composition as defined above has an elongation at break of more than 50% and a stress at threshold of less than 20 MPa, preferably less than 17 MPa, and even more preferably less than 14 MPa.

[0115] In another embodiment, the composition defined above has an elongation at break of more than 50% and an elongation at threshold of more than 3%, preferably more than 5%, and even more preferably more than 10%.

[0116] In another embodiment, the composition defined above has an elongation at break of greater than 50%, a stress at threshold less than 20 MPa, preferably less than 17 MPa, more preferably less than 14 MPa, and an elongation at threshold greater than 3%, preferably greater than 5%, more preferably greater than 10%.

[0117] Advantageously, the composition exhibits good abrasion resistance as measured according to ISO standard 9352: 2012. Advantageously, the composition of the invention after coating functions as an electrical insulator having a breakdown voltage measured according to IEC standard 60243-1.

[0118] Advantageously, the composition defined above has a high dielectric strength (greater than 5 kV / mm at 90° C.), measured in accordance with IEC standard 60243-1.

[0119] Advantageously, the composition defined above has a dielectric strength at 23° C. of greater than 40 kV / mm, preferably greater than 50 kV / mm.

[0120] Advantageously, the composition defined above exhibits a comparative tracking index (CTI), measured according to IEC 60112, of more than 600 V. This insulating property is maintained even during accelerated thermal aging up to 150° C.

[0121] Advantageously, the composition of the present invention after coating functions as an electrical insulator having a breakdown voltage of greater than 30 kV in direct current (DC) and greater than 15 kV in alternating current (AC) at a thickness of 500 μm, and a comparative tracking index (CTI) of greater than 600 V.

[0122] Advantageously, the composition of the invention after coating has a dielectric strength of greater than 5 kV / mm at 90° C. and a comparative tracking index (CTI) of greater than 600V.

[0123] Advantageously, the compositions of the present invention after coating function as electrical insulators having a dielectric strength of greater than 40 kV / mm, preferably greater than 50 kV / mm, and a comparative tracking index (CTI) of greater than 600 V at 23°C.

[0124] The composition of the present invention is fire resistant, having a result of V0 in the UL94 fire test at a thickness of 0.8 mm.

[0125] PEBA may be excluded In one embodiment, the composition does not include polyether block amide (PEBA).

[0126] Polyether block amide (PEBA) is a copolymer containing amide units (Ba1) and polyether units (Ba2), the amide units (Ba1) being units derived from at least one amino acid or units derived from at least one lactam, or at least one diamine, said diamine being chosen from linear or branched aliphatic or aromatic diamines or mixtures thereof; at least one carboxylic diacid, said diacid being chosen from aliphatic diacids or aromatic diacids, XY corresponds to an aliphatic repeat unit selected from units X and Y obtained by polycondensation of Said polyether units (Ba2) are derived in particular from at least one polyalkylene ether polyol, in particular a polyalkylene ether diol.

[0127] Reinforcing fibers may be excluded In one embodiment of the reinforcing fibers, the composition does not include reinforcing fibers selected from glass fibers, carbon fibers, basalt fibers, and basalt-based fibers.

[0128] In another embodiment, the composition does not comprise reinforcing fibers selected from reinforcing fibers of mineral, organic or vegetable origin.

[0129] Among the fibres of inorganic origin, mention may be made, inter alia, of carbon fibres, glass fibres, basalt fibres or fibres based on basalt, silica fibres or silicon carbide fibres. Among the fibres of organic origin, mention may be made, inter alia, of fibres based on thermoplastic or thermosetting polymers, such as semi-aromatic polyamide fibres, aramid fibres or polyolefin fibres. Among the fibres of plant origin, mention may be made, inter alia, of flax, hemp, silk, in particular spider silk, natural fibres based on sisal and other cellulose fibres, in particular viscose fibres.

[0130] According to another aspect, the present invention relates to the use of the composition defined above for coating, insulating and flame retarding electric battery busbars.

[0131] All the properties defined above are valid for this use.

[0132] The composition of the present invention makes it possible to cover the busbar with a thin layer of 0.1 mm to 2 mm, more particularly 0.2 mm to 1 mm, in particular 0.3 mm to 0.8 mm, more particularly 0.4 mm to 0.6 mm, whilst maintaining a high level of flexibility to accommodate deformations of the busbar.

[0133] A material that is too hard will form cracks or "waves" that are unsuitable for the application.

[0134] In one embodiment, said busbars are arranged inside and / or outside an electric battery, more particularly an electric battery of a vehicle, in particular an automobile.

[0135] According to yet another aspect, the present invention relates to a method of making a covered, insulated, flame retardant electric battery busbar, comprising the steps of extruding the composition defined above onto the electric battery busbar or powder coating said composition onto the electric battery busbar.

[0136] All the above defined properties are valid for the process.

[0137] In one embodiment, said busbars are arranged inside and / or outside an electric battery, more particularly an electric battery of a vehicle, in particular an automobile.

[0138] The invention will now be illustrated by the following non-limiting examples. EXAMPLES

[0139] The compositions in Table 1 were prepared by melt blending the polymer pellets with the flame retardant and additives. The blending was carried out by compounding in a co-rotating twin screw extruder with a diameter of 40 mm, with a flat temperature profile (T°) of 250° C. The screw speed was 300 rpm and the throughput was 70 kg / h.

[0140] The polyamide(s), polyolefin and additives are introduced during the compounding process in the main hopper. Flame retardants are added to the molten polymer in the center of the screw via a side feeder. If a plasticizer is present, it is also introduced into the molten polymer via a pump.

[0141] The composition was then extruded in the form of a 0.8 mm film by cast extrusion at a speed of 1 m / min, the temperature setting of the extruder was set at 230° C., the temperature setting of the film recovery roll was set at 65° C., and the mechanical properties and fire resistance were examined according to the following criteria:

[0142] Test samples are die cut from this film.

[0143] The elongation and stress at threshold and break were measured at 23°C on dry specimens (dumbbells cut from 0.8 mm thick films) according to ISO standard 527-1:2012.

[0144] The machine used is Instron 5966. The crosspiece speed is 50 mm / min.

[0145] Test conditions are 23°C ± 2°C on dry samples.

[0146] The compositions of the invention and the comparative compositions were tested by the flame propagation test, commonly referred to as UL94 and carried out in accordance with NFT standard 51072 on test specimens 0.8 mm thick. TIFF2024543172000003.tif187170

[0147] The dielectric strength of the alloy EI1 according to the invention was measured at 12 kV at 90° C., which was higher than the target set at 5 kV, so the invention also meets the requirements for electrical insulation. NC: Uncategorized PA 11 is Arkema PA 11 with a viscosity of 1.35. MXD10 is an Arkema PA with a viscosity of 0.9 derived from the polycondensation of m-xylylenediamine and sebacic acid. Exolit® OP1311 is a Clariant product (a flame retardant based on aluminum diethylphosphinate). BBSA (Benzyl butyl sulfonamide) Lotader AX8900: Copolymer of ethylene, methyl acrylate, and glycidyl methacrylate (Et / MA / GMA - 68 / 24 / 8 by weight) (SK functional polymer). Lotader 4700: Copolymer of ethylene, ethyl acrylate, and maleic anhydride (Et / EA / MAH--69 / 30 / 1 by weight) (SK functional polymer). Escor® 5000: Ethylene-acrylic acid copolymer (Exxon Mobil chemicals) Lowinox® 44B25 (CAS No.: 85-60-9), a phenolic primary antioxidant. Alkanox® 240 (CAS No.: 31570-04-4), secondary antioxidant based on phosphorous (Bren Melapur® MC25: Melamine cyanurate flame retardant (BASF)

[0148] Table 1 above shows that compositions EI1 and EI2 of the present invention show a result of V0 in the UL94 test, unlike comparative composition EC1 which does not contain MXD10 or comparative composition EC5 which has an amount of MXD10 less than 15%.

[0149] In addition, unlike comparative composition EC1 which does not contain MXD10, or comparative composition EC5 which contains less than 15% MXD10, or composition EC6 which does not contain polyolefin, or comparative compositions EC2-4 which contain more than 15% MXD10 but in which the flame retardant is not of the phosphinate type, only the compositions of the present invention show an elongation at break of more than 50%.

[0150] The compositions of the present invention also exhibit a threshold stress of less than 20 MPa and a threshold elongation of greater than 3%, unlike EC6 which does not contain polyolefin.

Claims

1. 1. A flame retardant insulating composition for covering electric battery bus bars, comprising, by weight: (a) 30 to 65%, more specifically 30 to 63.9%, and especially 30 to 60% of at least one semi-crystalline aliphatic polyamide; (b) 15 to 40%, more specifically 15 to 30%, of at least one semi-aromatic polyamide; (c) 15 to 30%, more specifically 20 to 25%, of at least one phosphinate-based flame retardant; (d) 5 to 20%, more specifically 5 to 15%, of at least one functionalized polyolefin; (e) 0-6%, more specifically 1-6%, and especially 2-4% of at least one plasticizer; (f) 0 to 10%, more specifically 0.1 to 5%, of at least one additive Including, The total of components (a) to (f) is 100%; Flame retardant insulating composition.

2. 2. The composition according to claim 1, characterized in that the polyamide is a long-chain polyamide having a number of carbon atoms per nitrogen atom of 8 or more, more particularly 9 or more, in particular 10 or more.

3. 3. The composition according to claim 2, characterized in that the long-chain polyamide is selected from PA610, PA612, PA1010, PA1012, PA11 and PA12.

4. 2. The composition according to claim 1, characterized in that the at least one semi-crystalline aliphatic polyamide is selected from PA1010, PA1012, PA11 and PA12, more particularly PA11 and PA12, and in particular PA11.

5. 2. The composition according to claim 1, characterized in that the semi-aromatic polyamide is a polyamide of the formula MXDY, where MXD corresponds to m-xylylenediamine and Y is a C6 to C18, in particular C9 to C18, more particularly C9 to C12 aliphatic dicarboxylic acid.

6. 6. The composition of claim 5, wherein the semi-aromatic polyamide of formula MXDY is selected from MXD6, MXD10, and MXD12, and more particularly MXD10.

7. 10. The composition of claim 1, wherein the flame retardant is a metal salt selected from metal salts of phosphinic acids, metal salts of diphosphinic acids, polymers comprising at least one metal salt of phosphinic acids, and polymers comprising at least one metal salt of diphosphinic acids.

8. 2. The composition of claim 1, wherein the polyolefin is crosslinked.

9. 2. The composition according to claim 1, characterized in that the additive is chosen from antioxidants, color pigments and flame retardant synergists, in particular nitrogen synergists, more particularly melamine-based synergists.

10. 10. The composition of claim 1, wherein the composition is free of polyether block amide (PEBA).

11. 10. The composition of claim 1, wherein the composition does not contain reinforcing fibers.

12. 10. Use of the composition of claim 1 for coating, insulating and flame retarding electric battery bus bars.

13. 13. Use according to claim 12, characterized in that the busbar is arranged inside and / or outside an electric battery, more particularly an electric battery of a vehicle, in particular an automobile.

14. 10. A method of making a covered, insulated, flame-retardant electric battery busbar, comprising the steps of extruding the composition of claim 1 onto the electric battery busbar or powder coating the composition onto the electric battery busbar.