Coloured polyamide composition for covering an electricity transmission component

Abstract

The invention relates to an electrically insulating composition for covering an electricity transmission component, the composition comprising: - predominantly at least one polyamide, the one or more polyamides having: - a difference, expressed in absolute value, between the total acidity of the one or more polyamides or and the total basicity of the one or more polyamides of less than 70, the total basicity and the total acidity being measured by potentiometry; and - a total basicity of less than 60 μeq / g measured by potentiometry, and the composition predominantly comprising at least one polyamide that has a number of carbon atoms per nitrogen atom greater than 6.5 and - at least one dye, characterised in that the colour of the composition is different from black, and its use for covering an electricity transmission component, preferably an electrical battery interconnection bar.

Description

COLORED POLYAMIDE COMPOSITION FOR COVERING ELECTRICITY TRANSPORT COMPONENTS (FIELD OF THE INVENTION

[0001] The present invention relates to a colored composition used for covering electricity transport components, and in particular electric battery interconnection bars. TECHNICAL BACKGROUND

[0002] In the field of electric vehicles, connectors called interconnection bars (or bus bars) are used to circulate high-intensity current inside and outside the batteries. These bars must be covered with an insulating coating that is resistant to mechanical stress and aging.

[0003] There are several processes for preparing busbars. The main one is the extrusion of the polymer composition around the central metal strip. Powder coating, dipping, or electrospray coating processes can also be used. These structures are then cut and bent (at room temperature) to the shape required by the vehicle layout.

[0004] For safety reasons, these bars must also have a distinctive color, representative of the current flowing in the bar. It is therefore essential that this color remains stable over time, despite the temperatures to which the bar may be subjected. Indeed, external conditions, proximity to the motor, self-heating during current flow, particularly during battery charging are factors that can affect the color of the coating over time. If the color changes over time, doubt may remain about the voltage of the electric current flowing in the bar, which could cause accidents during servicing or repair of the motor by example. It is therefore essential that the color remains stable despite the drastic conditions of its environment.

[0005] The technical problem related to the busbar application for batteries consists of forming a thin layer of polymer, whose color does not change over time, while maintaining a high level of flexibility to accommodate the deformation of the busbars. When bending, a material that is too rigid forms cracks on the external face and buckling on the internal face, which is visualized by 'waves' or 'bulges', phenomena which are prohibitive for the application.

[0006] The behavior at the yield point of the material is therefore crucial. Low yield stresses and high yield strain are sought. The strain levels of these coatings remain low, but the material must still have an elongation at break > 50%, preferably greater than 100%, and even more advantageously greater than 200%. Good abrasion resistance is also necessary for this application.

[0007] In addition, depending on the position of these parts within the engine, it may be beneficial for these compositions to be resistant to de-icing salt.

[0008] 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 of up to 130°C, particularly up to 150°C.

[0009] Finally, the rheological properties of the alloy must be adapted to the extrusion of thin polymer layers of the order of 0.5 mm.

[0010] Furthermore, the prior art does not provide information on the combinations to be made within the formulation to simultaneously achieve flexibility and color stability for the battery busbar application.

[0011] A composition based on polyamide and at least one pigment system is known from US 2021 / 0253854 and KR101977321. However, it appears that the disclosed compositions are not mechanically satisfactory. Furthermore, the color change of these products during aging is not documented. SUMMARY OF THE INVENTION

[0012] The invention relates to an electrically insulating composition for covering an electricity transmission component comprising: - predominantly at least one polyamide, the polyamide(s) having: - a difference, expressed in absolute value, between its total acidity and its total basicity less than 70 and - a total basicity less than 60 peq / g, and - predominantly at least one polyamide having a number of carbon atoms per nitrogen atom greater than 6.5 and - at least one coloring matter.

[0013] Preferably, the electrically insulating composition is characterized in that its color is different from a black color.

[0014] According to one embodiment, the electrically insulating composition may have an L* parameter greater than 0, preferably greater than 5, preferably greater than 10, measured in the CIELab system, as defined in the ISO 11664-4: 2008 standard, using a Konica Minolta CM-36dGV spectrophotometer in reflectance mode with a D65 illuminant, an angle of incidence of 10° and an aperture of 8mm and specular component included.

[0015] According to one embodiment, the electrically insulating composition may have a color determined according to the RAL method different from a RAL color of 2100, 6015, 7021, 8022, 9004, 9005, 9011, 9017 and 9021.

[0016] Preferably, the composition of the coating layer comprises from 60 to 98% by weight of said at least one polyamide.

[0017] Preferably, the composition of the coating layer is characterized in that said at least one polyamide is an aliphatic or cycloaliphatic polyamide, preferably aliphatic.

[0018] The invention also relates to its use for covering an electricity transmission component.

[0019] The invention also relates to an electricity transmission component comprising: - an electricity transport component having a metallic surface and - a coating layer in a composition as defined above.

[0020] Finally, the invention relates to a method for preparing an electricity transmission component.

[0021] It has been observed that the color of the composition according to the invention remains stable even after aging at high temperature. It has also been observed that the composition continues to exhibit certain electrical insulation properties after aging. Furthermore, the composition according to the invention exhibits good mechanical properties: the properties of elongation at break, impact resistance, and the resistance of the polymer layer during bending of the metal bar are very satisfactory. The composition also exhibits good chemical resistance, i.e. good resistance to de-icing salt. Finally, the electrical component covered with said composition remains easy to strip. Other advantageous characteristics of the method according to the invention are specified below: - the polyamide(s) have an inherent viscosity measured according to ISO 307:2007 greater than 1.1; -the polyamide(s) have a fusion enthalpy measured by DSC during the second heating according to standard ISO 11357-3:2013 strictly greater than 20 J / g; -the polyamide(s) have a crystallization temperature measured by DSC during the second heating according to the ISO 11357 standard- 3:2013 strictly less than 180°C; - the polyamide(s) have a total acidity of less than 60 peq / g; -the polyamide is chosen from PA11, PA12, PA1010, PA 1012, PA 610, PA 612, PA 516, PA613, PA912, PA 516, PA6 / 11, PA6 / 12, PA, 11 / 12, PA 6 / 11 / 12, PA 6 / 66 / 12, PA 6 / 1010, PA 6 / 1012, PA 6 / 1010 / 1012, PA 6 / 1012 / 12, PA 6 / 66 / 11 / 12, PA 6 / 1010 / 1012 / 1014 alone or as a mixture, more particularly PA11, PA12, PA1010, PA 1012, even more preferably PA11 or PA12, preferably PA11; -the coloring matter is a mixture of at least two pigments; - the coloring matter comprises titanium dioxide, tin oxide, zinc oxide and their mixture; -the coloring matter comprises titanium dioxide, tin oxide, zinc oxide and an orange-colored pigment; - the coloring matter is included in a content ranging from 0.5 to 10% by weight, preferably between 1 and 5% by weight relative to the total weight of the composition; -the composition comprises at least one antioxidant; - the metal surface of the electricity transmission component is made of copper, copper alloy, aluminum or aluminum alloy; - the component is an interconnection bar; -the method for preparing the electricity transmission component comprises a step of pre-treatment of the metal surface by degreasing and / or a singeing step and / or a pre-heating step. DETAILED DESCRIPTION

[0022] Other features, aspects, objects and advantages of the present invention will become even more apparent from the following description.

[0023] The nomenclature used to define polyamides is described in ISO 1874-1:2011 "Plastics - Polyamide (PA) materials for molding and extrusion - Part 1: Designation", particularly on page 3 (tables 1 and 2) and is well known to those skilled in the art. Thus, PA11 means that it is obtained by polycondensation of 11-aminoundecanoic acid. PA12 is obtained by polycondensation of lauryllactam. PA1010 is obtained by polycondensation of decanediamine (10) and decanedioic acid (10). PA1012 is obtained by polycondensation of decanediamine (10) and dodecanedioic acid (12).

[0024] It is further specified that the expressions "between... and..." and "from... to..." used in this description must be understood as including each of the limits mentioned.

[0025] The word "polyamide" covers both homopolyamides and copolyamides.

[0026] The invention is now described in more detail and in a non-limiting manner in the following description. Composition

[0027] The composition according to the invention is an electrically insulating composition for covering an electricity transmission component comprising: -predominantly at least one polyamide, the polyamide(s) having: -a difference, expressed in absolute value, between its total acidity and its total basicity of less than 70 and -a total basicity less than 60 peq / g, and -predominantly at least one polyamide having a number of carbon atoms per nitrogen atom greater than 6.5 and - at least one coloring matter.

[0028] Preferably, the electrically insulating composition is characterized in that its color determined by the RAL method is different from a black color. By "black color" is meant a RAL color of 2100, 6015, 7021, 8022, 9004, 9005, 9011, 9017 and 9021. The RAL colors of 2100, 6015, 7021, 8022, 9004, 9005, 9011, 9017 and 9021 correspond to black colors.

[0029] For the purposes of the present invention, electrically insulating means a material having a dielectric strength greater than 10 kV / mm measured on a 1 mm thick plate on a sample conditioned for 14 days at 25°C at 50% relative humidity according to IEC 60243-1:2013.

[0030] The composition mainly comprises at least one polyamide, that is to say one or more polyamides.

[0031] For the purposes of the present invention, the term “predominantly” means that the composition comprises at least one polyamide in a content greater than 50% by weight relative to the total weight of the composition. This or these polyamides constitute the matrix of the composition.

[0032] Preferably, the composition comprises between 60 and 98% by weight of at least one polyamide relative to the total weight of the composition, preferably between 70% and 95%. Polyamide

[0033] In the case of a homopolyamide of the PA-XY type, with X designating a unit obtained from a diamine and Y designating a unit obtained from a diacid, the number of carbon atoms per nitrogen atom is the average of the numbers of carbon atoms present in the unit resulting from the diamine X and in the unit resulting from the diacid Y. Thus PA6.12 is a PA with 9 carbon atoms per nitrogen atom, in other words a C9 PA. PA6.13 is C9.5. In the case of copolyamides, for example of the XaYa / XbYb structure, the number of carbon atoms per nitrogen atom is calculated according to the same principle. The calculation is carried out in molar proportion to the different amide units, i.e. the XaYa and XbYb units.

[0034] The majority polyamide present in the composition according to the invention has a number of carbon atoms per nitrogen atom greater than 6.5, preferably greater than 8.

[0035] By majority, it is meant for the purposes of the present invention that the composition comprises at least one polyamide in a content greater than 50% by weight relative to the total weight of the composition. In other words, the composition may comprise a mixture of polyamides having a number of carbon atoms per nitrogen atom greater than 6.5. This mixture must be in the majority, that is to say it must represent at least 50% by weight compared to the total weight of the composition.

[0036] Preferably, the composition comprises between 60 and 98% by weight of at least one polyamide relative to the total weight of the composition, preferably between 70% and 95%.

[0037] In other words, the presence of other polyamides is not excluded. However, it is important that high-carbon polyamides are the majority in the composition.

[0038] The polyamide present in the composition according to the invention is obtained by polycondensation of at least one unit chosen from a C6 to C18 alpha, omega-aminocarboxylic acid, a C5 to C12 lactam and a unit (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 being between 4 and 36.

[0039] The polyamide can be obtained by polycondensation of at least one lactam chosen from pyrrolidinone, 2-piperidinone, enantholactam, caprylolactam, pelargolactam, decanolactam, undecanolactam, and lauryllactam.

[0040] The polyamide present in the composition according to the invention can also be obtained by polycondensation of at least one amino acid chosen from 9-aminononanoic acid, 10-aminodecanoic acid (noted 10), amino-11-undecanoic acid (noted 11), amino-12-dodecanoic acid (noted 12).

[0041] The polyamide can be obtained by polycondensation of at least one unit 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 being between 4 and 36.

[0042] The unit (Ca diamine) can be aliphatic, cycloaliphatic or aromatic. It can be chosen from butanediamine (a=4), pentanediamine (a=5), hexanediamine (a=6), heptanediamine (a=7), octanediamine (a=8), nonanediamine (a=9), decanediamine (a= 10), undecanediamine (a= 11), dodecanediamine (a= 12), tridecanediamine (a= 13), tetradecanediamine (a= 14), hexadecanediamine (a= 16), octadecanediamine (a= 18), m-xylylenediamine (denoted MXD), methylpentamethylenediamine (denoted MPMD), bis(aminomethyl)cyclohexane (denoted BAC), meta-xylylenediamine (MXD, CAS No.: 1477-55-0) and para-xylylenediamine (PXD, CAS No.: 539-48-0).

[0043] Advantageously, said at least one diamine X in C6 to C12, is in particular chosen from 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine.

[0044] Advantageously, the diamine X used is C10 to C12, in particular chosen from 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine.

[0045] The unit (Cb diacid) can be aliphatic, cycloaliphatic or aromatic. It can be chosen from succinic acid (b=4), pentanedioic acid (b=5), adipic acid (b=6), heptanedioic acid (b=7), octanedioic acid (b=8), azelaic acid (b=9), sebacic acid (b= 10), undecanedioic acid (b= 11), dodecanedioic acid (b= 12), brassylic acid (b= 13), tetradecanedioic acid (b= 14), hexadecanedioic acid (b= 16), octadecanedioic acid (b= 18) and diacids obtained from fatty acids, terephthalic acid (denoted T).

[0046] Advantageously, said unit (Cb diacid) is chosen from adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid.

[0047] Advantageously, the polyamide present in the composition according to the invention has an elongation at break > 50%, preferably greater than 100%, even more advantageously greater than 200%. The elongation at break can be measured in particular according to the ISO 527-1 / -2 standard.

[0048] Advantageously, the composition according to the invention comprises less than 25% by weight of polyamide having an elongation at break of less than or equal to 50%, preferably less than 10% by weight, preferably less than 5% by weight, preferably less than 1% by weight, relative to the total weight of said composition. Preferably, the composition according to the invention is free of polyamide having an elongation at break of less than or equal to 50%.

[0049] Advantageously, the polyamide present in the composition according to the invention is aliphatic or cycloaliphatic, preferably the polyamide is aliphatic.

[0050] Advantageously, the polyamide present in the composition according to the invention is chosen from PA11, PA12, PA1010, PA 1012, PA 610, PA 612, PA516, PA613, PA912, PA6 / 11, PA6 / 12, PA11 / 12, PA 6 / 11 / 12, PA 6 / 66 / 12, PA 6 / 1010, PA 6 / 1012, PA 6 / 1010 / 1012, PA 6 / 1012 / 12, PA 6 / 66 / 11 / 12, PA 6 / 1010 / 1012 / 1014 alone or as a mixture.

[0051] Preferably, the composition only comprises polyamides having a number of carbon atoms per nitrogen atom greater than 6.5. More particularly, the composition only comprises polyamides having a number of carbon atoms per nitrogen atom greater than 8.

[0052] According to a preferred embodiment, the polyamide present in the composition according to the invention is a homopolyamide. This homopolyamide can be obtained by the polycondensation of a lactam, an amino acid or a (Ca diamine) or (Cb diacid) unit, with Ca and Cb being as defined above.

[0053] More particularly, the composition mainly comprises PA11, PA12, PA1010, PA 1012, even more preferably PA11 or PA12, preferably PA11.

[0054] PA11 has the advantage of being made from raw materials of plant origin. Plant materials can be grown in large quantities, depending on demand, across most of the globe and are bio-sourced. A bio-sourced raw material is a natural resource, animal or plant, whose stock can be replenished over a short period of time on a human scale. In particular, this stock must be able to renew itself as quickly as it is consumed.

[0055] The basic raw material for PA11 is castor oil, extracted from the castor bean plant (Castor oil in English). PA11 is obtained by polycondensation of 11-aminoundecanoic acid. Total acidity and total basicity

[0056] The polyamide(s) present in the composition according to the invention have(s) a difference, expressed in absolute value, between its total acidity and its total basicity strictly less than 70, preferably less than 50, ideally less than 30.

[0057] By difference, expressed as an absolute value, is meant, within the meaning of the present invention, the result of the subtraction of the values ​​of the total acidity of the polyamide(s) and the total basicity of the polyamide(s), without taking into account the sign.

[0058] When the composition contains a blend of polyamides, the acidity and basicity are measured on the blend of polyamides. The difference is therefore expressed for the blend of polyamides.

[0059] The polyamide(s) present in the composition according to the invention also have a total basicity strictly less than 60 peq / g, preferably less than 50 peq / g, and ideally less than 40 peq / g.

[0060] Preferably, the polyamide(s) present in the composition according to the invention also have a total acidity strictly less than 60 peq / g, preferably less than 50 peq / g, and ideally less than 40 peq / g.

[0061] Acidity and basicity are measured by potentiometry.

[0062] Acidity is measured using the following method. A sample of polyamide is dissolved in benzyl alcohol. This sample is then assayed potentiometrically using a 0.02N tetrabutylammonium hydroxide solution.

[0063] Basicity is measured using the following method. A sample of polyamide is dissolved in metacresol. This sample is then assayed potentiometrically using a 0.02N perchloric acid solution.

[0064] According to one embodiment of the invention, the polyamide(s) have a total basicity strictly less than 60 peq / g and a total acidity strictly less than 60 peq / g and a difference, expressed as an absolute value, between its total acidity and its total basicity strictly less than 50, ideally less than 30.

[0065] According to a preferred embodiment, the composition according to the invention mainly comprises PA11, PA12, PA1010 or PA 1012 and their mixture, this or these polyamides having a total basicity of less than 60 peq / g and a difference, expressed in absolute value, between its total acidity and its total basicity strictly less than 50, ideally less than 30.

[0066] According to a preferred embodiment, the composition according to the invention mainly comprises PA11 or PA12, having a total basicity of less than 50 peq / g and a total acidity of less than 60 peq / g and a difference, expressed in absolute value, between its total acidity and its total basicity strictly less than 30.

[0067] Preferably, the polyamide(s) present in the composition do not comprise a chain limiter. Inherent viscosity

[0068] Preferably, the polyamide(s) according to the invention have an inherent viscosity greater than 1.1, and preferably greater than 1.2, according to standard ISO 307:2007.

[0069] The measurement is carried out at 20°C on a 75 mg sample at a concentration of 0.5% (m / m) in m-cresol.

[0070] When the composition includes a mixture of polyamides, the viscosity is measured on the mixture of polyamides. Enthalpy of fusion

[0071] Preferably, the polyamide(s) have a fusion enthalpy greater than 20 J / g, preferably greater than 30 J / g and ideally greater than 40 J / g.

[0072] The enthalpy of fusion is measured by DSC (differential scanning calorimetry) according to ISO 11357-3:2013 (2 nd DSC heating at 20°C / min according to ISO 11357 standard).

[0073] When the composition includes a mixture of polyamides, the enthalpy of fusion is measured on the mixture of polyamides. Crystallization temperature

[0074] Preferably, the polyamide blend(s) have a crystallization temperature of less than 180°C, preferably less than 160°C.

[0075] The crystallization temperature is measured by DSC (differential scanning calorimetry) according to ISO 11357-3:2013 (2 ndDSC heating at 20°C / min according to ISO 11357 standard).

[0076] When the composition comprises a mixture of polyamides, the crystallization temperature is measured on the mixture of polyamides. The coloring matter

[0077] The composition according to the invention comprises at least one coloring matter. The coloring matter may be a dye or a pigment, in other words, water-soluble dyes or water-insoluble pigments according to the conditions defined below.

[0078] The dye may be of any type known to those skilled in the art. Preferably, the dye according to the invention is selected from the group consisting of azo dyes, anthraquinone dyes, dyes derived from indigo, triarylmethane dyes, chlorine dyes and polymethine dyes.

[0079] The term "pigment" means all pigments that provide color to a polymer composition. Their solubility in water at 25°C and atmospheric pressure (760 mmHg) is less than 0.05% by weight, and preferably less than 0.01%. The pigments that can be used are chosen in particular from organic and / or mineral pigments known in the art, in particular those described in the Kirk-Othmer Encyclopedia of Chemical Technology and in the Ullmann Encyclopedia of Industrial Chemistry.

[0080] Pigments can be of natural or non-natural origin. These pigments can be in the form of powder or pigment paste. They can be coated or uncoated. Pigments can, for example, be chosen from mineral pigments, organic pigments, and their mixtures.

[0081] By mineral pigment is meant any pigment that meets the definition of the Ullmann encyclopedia in the inorganic pigment chapter. Among the mineral pigments useful in the present invention, mention may be made of ochres such as red ochre (clay (in particular kaolinite) and iron hydroxide (hematite for example), brown ochre (clay (in particular kaolinite) and limonite), yellow ochre (clay (in particular kaolinite) and goethite); titanium dioxide, optionally surface-treated; zirconium or cerium oxides; zinc, iron (black, yellow or red), or chromium oxides; manganese violet, ultramarine blue, chromium hydrate and ferric blue; metal powders such as aluminum powder, copper powder.We can also cite alkaline earth metal carbonates (such as calcium, magnesium), silicon dioxide, quartz, as well as any other compound used as an inert filler in cosmetic compositions, as long as these compounds bring color or white to the composition under the conditions in which they are used.

[0082] Preferably, a composition of the invention is free of salts of the metals mentioned above, in particular aluminum salts or copper salts.

[0083] The pigment may be an organic pigment. By "organic pigment" we mean any pigment that meets the definition in the Ullmann Encyclopedia in the organic pigment chapter.

[0084] The organic pigment may in particular be chosen from nitroso, nitro, azo, xanthene, pyrene, quinoline, quinoline, anthraquinone, triphenylmethane, fluorane, phthalocyanine, metal complex type compounds, isoindolinone, isoindoline, quinacridone, perinone, perylene, diketopyrrolopyrrole, indigo, thioindigo, dioxazine, triphenylmethane, quinophthalone.

[0085] In particular, the white or colored organic pigments may be chosen from carmine, carbon black, aniline black, azo yellow, quinacridone, phthalocyanine blue, the blue pigments codified in the Color Index under the references Cl 42090, 69800, 69825, 74100, 74160, the yellow pigments codified in the Color Index under the references Cl 11680, 11710, 19140, 20040, 21100, 21108, 47000, 47005, the green pigments codified in the Color Index under the references Cl 61565, 61570, 74260, the orange pigments codified in the Color Index under the references Cl 11725, 45370, 71105, the red pigments codified in the Color Index under the references Cl 12085, 12120, 12370, 12420, 12490, 14700, 15525, 15580, 15620, 15630, 15800, 15850, 15865, 15880, 26100, 45380, 45410, 58000, 73360, 73915, 75470.

[0086] Advantageously, the pigment is selected from the pigments Cl Pigment Orange 82 [CAS No. 2170864-77-2] and Cl Pigment Yellow 216 [(CAS No. 817181 -98-9]. Pigment Orange 82 may be obtained, for example, under the name Sicopal® Orange K2430 from Sun Chemical, Ludwigshafen, Germany. Pigment Yellow 216 may be obtained, for example, under the name Orange 10P340 from Shepherd, Gent, Belgium.

[0087] Among the colorants, carminic acid may be mentioned. Also mentioned are the colorants known under the following names: D & C Red 21 (Cl 45 380), D & C Orange 5 (Cl 45 370), D & C Red 27 (Cl 45 410), D & C Orange 10 (Cl 45 425), D & C Red 3 (Cl 45 430), D & C Red 4 (Cl 15 510), D & C Red 33 (Cl 17 200), D & C Yellow 5 (Cl 19 140), D & C Yellow 6 (Cl 15 985), D & C Green (Cl 61 570), D & C Yellow 1 O (Cl 77 002), D & C Green 3 (Cl 42 053), D & C Blue 1 (Cl 42 090).

[0088] The coloring matter may be selected from the group consisting of titanium dioxide, carbon black, cobalt oxide, nickel titanate, molybdenum disulfide, aluminum flakes, iron oxide, zinc oxide, organic pigments, such as phthalocyanine and anthraquinone derivatives, and zinc phosphate.

[0089] According to any one of the embodiments, the composition according to the invention comprises less than 1% by weight, in particular less than 0.1% by weight, of carbonaceous filler, relative to the total weight of said composition.

[0090] For the purposes of the invention, the term "carbon filler" means a particulate object containing in its mass only carbon atoms, "apart from impurities", it being understood that there may be other atoms on the surface. A carbon filler may be chosen, without being exhaustive, from carbon blacks, natural and synthetic graphites, carbon fibers, graphenes, fullerenes, acetylene blacks and carbon nanotubes.

[0091] According to any one of the embodiments, the composition according to the invention comprises less than 0.1% by weight of carbon black, relative to its total weight. Preferably, the composition according to the invention is free of carbon black.

[0092] Preferably, the composition according to the invention comprises at least one coloring material leading to a color different from the color black.

[0093] Preferably, the composition according to the invention comprises less than 1% by weight, in particular less than 0.1% by weight, preferably 0% by weight, relative to its total weight, of coloring matter having an L* parameter less than 10, in particular less than 5, in particular less than 1, in particular equal to 0, with the L* parameter being measured in the CIELab system, as defined in the ISO 11664-4: 2008 standard, using a Konica Minolta CM-36dGV spectrophotometer in reflectance mode with a D65 illuminant, an angle of incidence of 10° and an aperture of 8mm and specular component included.

[0094] Preferably, the chosen coloring material(s) lead to a composition having:

[0095] - a parameter L* between 10 and 100, preferably between 20 and 80, advantageously between 40 and 75, in particular between 50 and 70, and / or

[0096] - a parameter a* between 10 and 100, preferably between 20 and 80, advantageously between 35 and 55, and / or

[0097] - a parameter b* between 10 and 100, preferably between 20 and 80, advantageously between 40 and 75, in particular between 50 and 70, with said parameters L*, a* and b* being measured in the CIELab system, as defined in the ISO 11664-4: 2008 standard, using a Konica Minolta CM-36dGV spectrophotometer in reflectance mode with a D65 illuminant, an angle of incidence of 10° and an aperture of 8mm and specular component included.

[0098] Preferably, the composition according to the invention comprises at least one coloring material leading to an orange color.

[0099] Preferably, the chosen colorant(s) result in a RAL 2003 color composition, i.e. have the following L*a*b* values: L* = 66.0; a* = 41.2 and b* = 52.4.

[0100] Advantageously, the coloring matter is a mixture of at least two pigments. More preferably, the coloring matter comprises titanium dioxide, tin oxide, zinc oxide and their mixture. Even more preferably, the coloring matter comprises titanium dioxide, tin oxide, zinc oxide and at least two additional pigments, preferentially leading to the orange color.

[0101] Preferably, the coloring matter content in the composition is between 0.5 and 10%, advantageously between 1 and 5% by weight relative to the total weight of the composition.

[0102] Preferably, the content of black coloring matter and in particular black pigment, carbon black or other black filler is limited to 0.1% by weight maximum.

[0103] Preferably, black coloring materials are excluded.

[0104] Preferably, the color of the composition is characterized in that the color measured by the RAL method is different from a RAL color of 2100, 6015, 7021, 8022, 9004, 9005, 9011, 9017 or 9021.

[0105] Preferably, the composition according to the invention comprises between 60 and 98% by weight, preferably between 70 and 95% by weight, of polyamide and between 0.5 and 10% by weight, preferably between 1 and 5% by weight of coloring matter. Additives

[0106] Preferably, the composition according to the invention comprises at least one additive chosen from flame retardants, UV protective agents, UV stabilizers, heat stabilizers, lubricants, fluidity improving agents, flowability improving agents, film-forming agents, fillers, film-forming auxiliaries, gums, preservatives, antibacterial agents and mixtures thereof. Preferably, the composition according to the invention does not comprise metal-based additives, so as to avoid any harmful interaction between the metal surface to be coated and these additives potentially present within the composition according to the invention. Antioxidants

[0107] Preferably, the composition according to the invention comprises at least one antioxidant

[0108] For example, the stabilizer may be an organic stabilizer or more generally a combination of organic stabilizers, such as a phenol-type antioxidant (for example of the type of irganox® 245 or 1098 or 1010 from the company Ciba-BASF), a phosphite-type antioxidant (for example irgafos® 126 or Irgafos® 168 from the company Ciba-BASF) and possibly other stabilizers such as a HALS, which stands for Hindered Amine Light Stabilizer or hindered amine light stabilizer (for example Tinuvin® 770 from the company Ciba-BASF), a UV stabilizer (for example Tinuvin® 312 from the company Ciba), a phosphorus-based stabilizer. It is also possible to use amine-type antioxidants such as Naugard® 445 from Crompton or polyfunctional stabilizers such as Nylostab® S-EED from Clariant.

[0109] The composition according to the invention thus exhibits color stability following thermal aging at 150°C for 150 hours, which is expressed with an AE < 10 for a 1 mm thick plate made of the composition. This color stability following thermal aging at 150°C for 150 hours is expressed by an AE < 20 for a 1 mm thick plate covering a copper substrate.

[0110] In another embodiment, the composition defined above has a threshold stress < 60 MPa, preferably < 50 MPa.

[0111] In yet another embodiment, the composition defined above has an elongation at the threshold > 3%, advantageously > 4% measured according to standard ISO 527-1 / 2:2012.

[0112] Advantageously, said composition has good abrasion resistance as measured according to standard ISO 9352:2012. Advantageously, the compositions of the invention after coating have a role as an electrical insulator with a high dielectric strength at 23°C (greater than 20 kV / mm, advantageously greater than 25 kV / mm) as measured according to standard IEC 60243-1:2013.

[0113] Advantageously, the compositions defined above have a high dielectric strength at 90°C (>5 kV / mm) as measured according to standard IEC 60243-1:2013.

[0114] Advantageously, the compositions defined above have a “comparative tracking index” (CTI) > 600V as measured according to IEC 60112:2020. This insulation is preserved during accelerated thermal aging of up to 130°C, in particular up to 150°C.

[0115] Advantageously, the compositions of the invention after covering have a role of electrical insulator with a breakdown voltage for a thickness of 500 pm > 20 kV in direct current (DC) and > 10 kV in alternating current (AC) and a “comparative tracking index” (CTI) > 600 V. Use

[0116] According to another aspect, the present invention relates to the use of the composition as defined above, for covering an electricity transport component, preferably an electric battery interconnection bar.

[0117] All the characteristics defined above are valid for this use.

[0118] The composition of the invention makes it possible to cover the interconnection bar with a thin layer of 0.1 mm to 2 mm, in particular 0.2 mm to 1 mm, in particular 0.3 mm to 0.8 mm, more particularly 0.4 mm to 0.6 mm, while retaining a high level of flexibility to accommodate the deformation of the interconnection bars.

[0119] A material that is too rigid forms cracks or “waves” which are prohibitive for the application. Electricity transmission component

[0120] The invention also relates to an electricity transmission component comprising: - an electricity transport component having a surface metallic and - a coating layer in a composition as defined above.

[0121] Preferably, the metal surface is copper, copper alloy, aluminum or aluminum alloy, preferably copper and copper alloy.

[0122] Preferably, the thickness of the coating layer is from 0.1 mm to 2 mm, in particular from 0.2 mm to 1 mm, in particular from 0.3 mm to 0.8 mm, more particularly from 0.4 mm to 0.6 mm.

[0123] According to a particular embodiment of the invention, the coating layer is in direct contact with the metal surface.

[0124] According to another embodiment, the electricity transport component comprises an intermediate layer located between the metal surface and the coating layer. Middle layer

[0125] According to a particular embodiment, an intermediate layer is arranged between the metal surface and the composition according to the invention.

[0126] The intermediate layer may be a crosslinked adhesion primer layer, a metallic layer or a polyolefin layer. Intermediate layer of crosslinked adhesion primer

[0127] In a first embodiment, the intermediate layer is a crosslinked adhesion primer layer. Preferably, this layer completely covers the metal surface.

[0128] The adhesion primer is in particular as defined in the ISO12944-5:2018 standard. Preferably, the adhesion primer contains an acrylic polymer, a saturated or unsaturated polyester, an alkyd, a polyurethane, a polyether, a polyvinyl, a cellulose or silicon-based product, their copolymers or mixtures thereof. Preferably, the adhesion primer contains reactive groups such as epoxide, carboxylic acid, hydroxyl, isocyanate, amide, carbamate, amine or carboxylate groups or a mixture of these groups.

[0129] Preferably, the adhesion primer is a compound composition comprising epoxy, urethane, acrylic and / or polyester functions. Preferably, the adhesion primer is an epoxy acrylate composition (for example Primgreen LAT 12035 marketed by the company Arkema).

[0130] After deposition on the metal surface, or preferably on the metal bar, the primer composition is crosslinked. Crosslinking can be done in any way known to those skilled in the art, using initiators or crosslinking catalysts, by volatilization of the solvent, and in particular by heating or by UV irradiation. The heating temperature for crosslinking will depend on the adhesion primer used, for example in the case of an epoxy acrylate type adhesion primer the crosslinking temperature can be around 300°C.

[0131] Crosslinking can be carried out in two ways. According to a first embodiment, the adhesion primer can consist of a base resin applied first to the metal surface and a crosslinking agent applied in a second step. The crosslinking agent allows the crosslinking of the base resin, the crosslinking being triggered by a heating step, for example. In a second embodiment, the adhesion primer is a compound capable of self-crosslinking. It is a base resin comprising functions capable of crosslinking.

[0132] The crosslinked adhesion primer layer preferably has a thickness of between 2 and 100 μm, preferably between 5 and 50 μm.

[0133] Particularly advantageously, the crosslinked adhesion primer layer allows a stable color to be maintained over time, even at high temperatures, while maintaining mechanical strength and adhesion between the coating layer and the metal surface. In addition, the presence of the adhesion primer layer has been shown to provide resistance to salt spray corrosion. Metallic intermediate layer

[0134] In a second embodiment, the intermediate layer is a metal layer. Preferably, this layer covers the entire metal surface of the electricity transmission component.

[0135] Preferably, the metal of the intermediate layer may be of any type provided that it is not copper or a copper alloy.

[0136] Preferably, the metallic intermediate layer may be a layer of chromium, nickel, zinc, tin, manganese, aluminum, platinum, gold, silver, or alloys of these metals.

[0137] The metallic intermediate layer may be formed on the metallic surface of the electrically transporting component by any method known to those skilled in the art. The metallic intermediate layer may be obtained by electrodeposition or by deposition of a metal foil or by plasma-enhanced chemical vapor deposition on the metallic surface of the electrically transporting component. Electrodeposition is a well-known technique which consists of immersing the metallic component to be coated in a solution containing the metallic ions of the metal chosen for the intermediate layer and applying an electric current, the metallic ions then being deposited on the metallic surface of the electrically transporting component. The metallic intermediate layer may also be chromium and be generated by chromating techniques. The metallic intermediate layer may also be a metallic phosphate layer obtained by phosphating.

[0138] The metallic intermediate layer preferably has a thickness of between 0.1 and 10 μm, preferably between 0.5 and 5 μm.

[0139] Particularly advantageously, the metallic intermediate layer allows a stable color to be maintained over time even at high temperatures while maintaining mechanical resistance. Polyolefin intermediate layer

[0140] In a third embodiment, the intermediate layer is a polyolefin layer. Preferably, this layer completely covers the metal surface of the electricity transport component.

[0141] The polyolefin is preferably selected from functionalized, non-functionalized polyolefins and a mixture of the two.

[0142] For simplicity, the polyolefin has been designated (B) and functionalized polyolefins (B1) and non-functionalized polyolefins (B2) have been described below. A non-functionalized polyolefin (B2) is typically a homopolymer or copolymer of alpha olefins or diolefins, such as, for example, ethylene, propylene, butene-1, octene-1, butadiene. Examples include: - homopolymers and copolymers of polyethylene, in particular LDPE, HDPE, LLDPE (linear low density polyethylene), VLDPE (very low density polyethylene) and metallocene polyethylene, - homopolymers or copolymers of propylene, - ethylene / alpha-olefin copolymers such as ethylene / propylene, EPR (abbreviation of ethylene-propylene-rubber) and ethylene / propylene / diene (EPDM), -THE styrene / ethylene-butene / styrene block copolymers (SEBS). styrene / butadiene / styrene (SBS). styrene / isoprene / styrene (SIS), styrene / ethylene-propylene / styrene (SEPS). - copolymers of ethylene with at least one product chosen from salts or esters of unsaturated carboxylic acids such as alkyl (meth)acrylate (for example methyl acrylate), or vinyl esters of saturated carboxylic acids such as vinyl acetate (EVA), the proportion of comonomer being able to reach 40% by weight.

[0143] Preferably, the functionalized polyolefin (B1) is a polymer of alpha olefins having reactive units (the functionalities); such reactive units are acid, anhydride, or epoxy functions. By way of example, mention may be made of the preceding polyolefins (B2) grafted or co- or terpolymerized by unsaturated epoxides such as glycidyl (meth)acrylate, or by carboxylic acids or the corresponding salts or esters such as (meth)acrylic acid (the latter being able to be neutralized totally or partially by metals such as Zn, etc.) or also by carboxylic acid anhydrides such as maleic anhydride. A functionalized polyolefin is for example a PE / EPR blend, the weight ratio of which can vary widely, for example between 40 / 60 and 90 / 10, said blend being co-grafted with an anhydride, in particular maleic anhydride, according to a grafting rate for example of 0.01 to 5% by weight.

[0144] Preferably, the functionalized polyolefin (B1) is chosen from the following (co)polymers, grafted with maleic anhydride or glycidyl methacrylate, in which the grafting rate is for example from 0.01 to 5% by weight: - PE, PP, copolymers of ethylene with propylene, butene, hexene, or octene containing for example 35 to 80% by weight of ethylene; - ethylene / alpha-olefin copolymers such as ethylene / propylene, EPR (abbreviation of ethylene-propylene-rubber) and ethylene / propylene / diene (EPDM); - styrene / ethylene-butene / styrene (SEBS), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), styrene / ethylene-propylene / styrene (SEPS) block copolymers; - ethylene and vinyl acetate (EVA) copolymers, containing up to 40% by weight of vinyl acetate; - ethylene and alkyl (meth)acrylate copolymers, containing up to 40% by weight of alkyl (meth)acrylate; - ethylene vinyl acetate (EVA) and alkyl (meth)acrylate copolymers, containing up to 40% by weight of comonomers.

[0145] Preferably, the functionalized polyolefin (B1) is chosen from ethylene / propylene copolymers with a majority of propylene grafted with maleic anhydride then condensed with mono-amine polyamide (or a polyamide oligomer) (products described in EP-A-0342066).

[0146] Preferably, the functionalized polyolefin (B1) is a co- or terpolymer of at least the following units: (1) ethylene, (2) alkyl (meth)acrylate or saturated carboxylic acid vinyl ester and (3) anhydride such as as maleic anhydride or (meth)acrylic acid or epoxy such as glycidyl (meth)acrylate.

[0147] As examples of functionalized polyolefins of the latter type, the following copolymers may be mentioned, 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: - 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 copolymers.

[0148] In the above copolymers, (meth)acrylic acid can be salified with Zn or Li.

[0149] The term "alkyl (meth)acrylate" in (B1) or (B2) means C1-C8 alkyl methacrylates and 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.

[0150] Preferably, the abovementioned polyolefins (B1) can also be crosslinked by any suitable process or agent (diepoxy, diacid, peroxide, etc.); the term functionalized polyolefin also includes mixtures of the abovementioned polyolefins with a difunctional reagent such as diacid, dianhydride, diepoxy, etc. capable of reacting with them or mixtures of at least two functionalized polyolefins capable of reacting with each other.

[0151] Preferably, the above-mentioned copolymers (B1) and (B2) are copolymerized in a random or block manner and have a linear or branched structure.

[0152] The molecular weight, MFI index, density of these polyolefins can also vary to a large extent, which the person skilled in the art will appreciate. MFI, short for Melt Flow Index, is the melt flow index. It is measured according to ASTM 1238.

[0153] Preferably, the non-functionalized polyolefins (B2) are chosen from homopolymers or copolymers of polypropylene and any homopolymer of ethylene or copolymer of ethylene and a comonomer of higher alpha olefin type such as butene, hexene, octene or 4-methyl-1-pentene. Examples that may be mentioned are PP, high density PE, medium density PE, linear low density PE, low density PE, very low density PE, block copolymers propylene / styrene (SEPS). These polyethylenes are known to those skilled in the art as being produced using a “radical” process, using “Ziegler” type catalysis or, more recently, using so-called “metallocene” catalysis.

[0154] Preferably, the functionalized polyolefins (B1) are chosen from any polymer comprising alpha olefinic units and units carrying polar reactive functions such as epoxy, carboxylic acid or carboxylic acid anhydride functions. Examples of such polymers include terpolymers of ethylene, alkyl acrylate and maleic anhydride or glycidyl methacrylate such as Lotader® (SK functional polymer) or polyolefins grafted with maleic anhydride such as Orevac® (SK functional polymer) as well as terpolymers of ethylene, alkyl acrylate and (meth)acrylic acid. Homopolymers or copolymers of polypropylene grafted with a carboxylic acid anhydride and then condensed with polyamides or monoamine oligomers of polyamide may also be mentioned.

[0155] In one embodiment, the polyolefin is functionalized.

[0156] Advantageously, the non-functionalized polyolefin is chosen from a polyethylene and a polypropylene, in particular a polyethylene, in particular a low density polyethylene (LDPE).

[0157] The polyolefin layer preferably has a thickness of between 10 and 1000 pm, preferably between 30 and 500 pm, advantageously between 50 and 300 pm.

[0158] Particularly advantageously, the polyolefin layer allows a stable color to be maintained over time even at high temperatures while allowing good adhesion of the coating layer and mechanical resistance.

[0159] Any other organic polymer could be used to replace the polyolefin layer according to the invention.

[0160] According to another embodiment, the coating layer of a composition as defined above is the outermost layer of the component. The electricity transport component can be of any type. It is mainly a high voltage electricity transport component. This component can be in the form of a metal cable or comprising metal fibers, for example braided, or thin superimposed metal sheets or metal bars such as those usually used in interconnection bars.

[0161] Preferably, the electricity carrying component is an electrical or electronic component cover, a control device, a connector, a battery cover, an electrical box, an electrical terminal or a cable.

[0162] Preferably, the electricity transmission component is a busbar.

[0163] In one embodiment, said interconnection bar is located inside and / or outside electric batteries, in particular vehicle electric batteries, in particular motor vehicles. It may for example be immersed in a coolant. Process for preparing the electricity transmission component

[0164] According to yet another aspect, the present invention relates to a method of preparing an electricity transmission component comprising a step of covering the metal surface of the electricity transport component by a composition as defined above.

[0165] Preferably, the present invention relates to a method for preparing an interconnection bar comprising a step of covering the metal surface of the electricity transport component with a composition as defined above.

[0166] The coating step may be a step of extruding a composition as defined above onto the metal surface of the electricity transport component or a step of powder coating said composition onto the metal surface of the electricity transport component.

[0167] Preferably, the preparation method does not include a step of powder coating said composition on an electric battery interconnection bar.

[0168] It is possible for the metal surface to undergo a pretreatment step before being covered with the composition according to the invention. Thus, before the covering step, the method may comprise a step of degreasing the metal surface and / or a singeing step and / or a preheating step.

[0169] Preferably, the electricity transmission component is an electric battery interconnection bar.

[0170] This metal bar can be solid. But it can also be made of a multitude of braided metal filaments, which gives it great flexibility. Intermediate layer of crosslinked adhesion primer

[0171] According to another embodiment, the present invention relates to a method for preparing an electricity transport component, preferably an interconnection bar, in particular an electric battery, comprising: - coating the entire metal surface of the electricity transmission component, preferably the interconnection bar, with an intermediate layer of adhesion primer as defined above then crosslinking of said layer; - a step of extruding a coating composition as defined above onto the metal surface previously covered with the adhesion primer layer.

[0172] Preferably, after the application of the adhesion primer layer, the method comprises an additional step of evaporation of the solvent, then possibly a baking step, or a heating step, or a UV irradiation step. Depending on the adhesion primer chosen, this step may allow the crosslinking of the primer. It is possible for the metal surface of the electricity transport component, preferably the metal bar of the interconnection bar, to undergo a pre-treatment step before being covered by the intermediate layer of primer. The method may comprise, for example, a step of degreasing the metal surface and / or a singeing step and / or a pre-heating step. Metallic intermediate layer

[0173] According to another embodiment, the present invention relates to a method for preparing an electricity transport component, preferably an interconnection bar, in particular an electric battery, comprising: - coating the metal surface of the electricity transport component, preferably an interconnection bar, with a metal intermediate layer as defined above; - a step of extruding a coating composition as defined above onto the metal surface previously covered with the metal intermediate layer.

[0174] Preferably, the metal intermediate layer is deposited on the metal surface of the electrically transporting component by the methods described above, preferably by electrodeposition.

[0175] It is possible that the metal surface of the electricity carrying component, preferably the metal bar of the bar interconnection, undergoes a pre-treatment step before being covered by the metallic intermediate layer. The method may comprise, for example, a step of degreasing the metallic surface and / or a singeing step and / or a pre-heating step. Polyolefin intermediate layer

[0176] According to another embodiment, the present invention relates to a method for preparing an electricity transport component, preferably an interconnection bar, in particular an electric battery, comprising: - a step of coating the entire metal surface of the electricity transport component, preferably the interconnection bar, with an intermediate layer of polyolefin as defined above; - a step of coating the intermediate polyolefin layer with a coating composition as defined above.

[0177] Preferably, the step of covering the intermediate polyolefin layer with a coating composition as defined above can be carried out by extrusion of the composition or by depositing a powder of said coating composition and then melting the powder.

[0178] Preferably, the preparation method comprises an extrusion step and does not comprise a powder coating step.

[0179] It is possible for the metal surface of the electricity transport component, preferably the metal bar of the interconnection bar, to undergo a pre-treatment step before being covered by the polyolefin intermediate layer. The method may comprise, for example, a step of degreasing the metal surface and / or a singeing step and / or a pre-heating step.

[0180] All the characteristics defined above are valid for the process.

[0181] Other aims and advantages of the present invention will appear on reading the following examples given without any limitation being implied. EXAMPLES ] Example 1 Preparation of the compositions

[0182] Compositions according to the invention and comparative compositions were prepared using the following compounds.

[0183] The polyamide according to the invention, denoted PA11 A, is prepared according to the following process. 43.00 kg of 11-aminoundecanoic acid, 30 g of phosphoric acid and 6.0 kg of deionized water are loaded into an autoclave and heated to 250°C while maintaining autogenous pressure for 30 min. As soon as the monomer melts, the medium is stirred at 40 rpm for the entire duration of the synthesis. A progressive expansion is applied for 2 hours up to 1 bar while raising the temperature to 255°C. A nitrogen sweep at a flow rate of 100 L / h is then applied for 30 minutes while maintaining the temperature at 255°C. Finally, stirring is stopped and the melt extruded under a pressure of 6 bars. The rod is cooled in a water bath and then granulated.

[0184] The polyamide denoted PA11 B is prepared according to the following process. 33.00 kg of 11-amino-undecanoic acid, 79.8 g of potash and 5.50 kg of deionized water are loaded into an autoclave and heated to 220°C while maintaining autogenous pressure for 1 h. As soon as the monomer melts, the medium is stirred at 40 rpm for the entire duration of the synthesis. A progressive expansion is applied for 75 minutes up to 10 bar while raising the temperature to 260°C. Then an expansion in one hour up to 0.3 bar is applied while maintaining the temperature at 260°C. A nitrogen sweep at a flow rate of 100 L / h is then applied for 15 minutes while maintaining the temperature at 260°C. Finally, stirring is stopped and the melt extruded under a pressure of 10 bar. The rush is cooled in a water bath, then granulated.

[0185] The polyamide denoted PA11 C is prepared according to the following process. 26.35 kg of 11-amino-undecanoic acid, 0.214 kg of adipic acid and 5.40 kg of deionized water are loaded into an autoclave and heated to 235°C while maintaining autogenous pressure for 90 minutes. As soon as the monomer melts, the medium is stirred at 40 rpm for the entire duration of the synthesis. A progressive expansion is applied for 2 hours up to 0.3 bar while maintaining the temperature at 235°C. A nitrogen sweep at a flow rate of 100 L / h is then applied for 90 minutes while maintaining the temperature at 260°C. Finally, stirring is stopped and the melt extruded under a pressure of 6 bars. The rod is cooled in a water bath, then granulated.

[0186] The polyamide according to the invention PA12 A is prepared according to the following process. 25.00 kg of laurolactam and 2.20 kg of deionized water are loaded into an autoclave and heated to 290°C under a pressure of 32 bar for 5 hours. As soon as the monomer melts, the medium is stirred at 40 revolutions per minute for the entire duration of the synthesis. A progressive pressure reduction is applied for 8 hours up to 8 bars while maintaining the temperature at 290°C. Then a pressure reduction in one hour down to 0.2 bar is applied by gradually lowering the temperature to 265°C. A nitrogen sweep at a flow rate of 100 L / h is then applied for 15 minutes while maintaining the temperature at 265°C. Finally, a vacuum is applied to bring the pressure to 0.3 bar for 15 minutes. Finally, the stirring is stopped and the melt extruded under a pressure of 10 bars. The rush is cooled in a water bath, then granulated.

[0187] Polyamide PA12 B is prepared according to the following process. 30.00 kg of laurolactam, 0.160 kg of adipic acid and 2.00 kg of deionized water are loaded into an autoclave and heated to 290°C under a pressure of 32 bar for 5 hours. As soon as the monomer melts, the medium is stirred at 40 revolutions per minute for the entire duration of the synthesis. A progressive expansion is applied for 8 hours up to 8 bars while maintaining the temperature at 290°C. Then an expansion in one hour up to 0.2 bar is applied by gradually lowering the temperature to 265°C. A nitrogen sweep at a flow rate of 100 L / h is then applied for 15 minutes while maintaining the temperature at 265°C. Finally, a vacuum is applied to bring the pressure to 0.3 bar for 15 minutes. Finally, stirring is stopped and the melt extruded under a pressure of 10 bar. The rod is cooled in a water bath and then granulated.

[0188] A polyamide blend is prepared by melt blending the polyamides. This blend consists of 84% by weight of PA 11 A and 16% by weight of PA 11 B.

[0189] The tested polyamides and the polyamide blend have the characteristics indicated in Table 1 below: Table 1 Measurement of total basicity

[0190] Basicity is measured using the following method. 1 g of polyamide is dissolved in 80 mL of hot metacresol. The sample is then cooled. Then, it is determined by potentiometry using a Metrohm titrator (888 or 716) with a combined pH electrode, by a solution of 0.02N perchloric acid in acetic acid. The potential versus volume curve gives a jump with an equivalent volume from which the total basicity is calculated using the following formula: Veq X [HC104] Total basicity (meq / g) = - m in which Veq denotes the equivalent volume obtained using potentiometric dosing, [HCIO4] denotes the concentration of the perchloric acid solution, i.e. 0.02 N, m denotes the mass of the sample, i.e. 1 g. Total acidity measurement

[0191] Acidity is measured using the following method. 1 g of polyamide is dissolved in 80 mL of hot benzyl alcohol. The sample is then cooled. Then, it is determined by potentiometry using a Metrohm titrator (888 or 716) with a combined pH electrode, with a 0.02N tetrabutylammonium hydroxide solution. The potential versus volume curve gives a jump with an equivalent volume from which the total acidity is calculated using the following formula: Veq X [TBAOH] Total acidity (meq / g) = - m in which Veq denotes the equivalent volume obtained using potentiometric dosing, [TBAOH] denotes the concentration of tetrabutylammonium hydroxide solution, i.e. 0.02 N, m denotes the mass of the sample, i.e. 1 g. Calculation of the difference between total acidity and basicity

[0192] The difference is obtained by calculating the subtraction of the values ​​between the total acidity and the total basicity, in absolute value, that is to say without taking into account the sign.

[0193] For example, for PA 11 A: = |57 - 48| = 9 Measurement of inherent viscosity

[0194] The measurement is carried out at 20°C on a 75 mg sample at a concentration of 0.5% (m / m) in m-cresol. The inherent viscosity is calculated according to the following formula: Inherent viscosity = ln(t s / to) x 1 / C, with C = m / px 100, in which t sis the flow time of the solution, to is the flow time of the solvent, m is the mass of the sample whose viscosity is determined and p is the mass of the solvent. This measurement corresponds to the ISO 307:2007 standard except that the measurement temperature is 20°C instead of 25°C. Measurement of the enthalpy of fusion

[0195] The enthalpy of fusion is determined according to ISO 11357-3:2013 by DSC during the second heating. Measurement of crystallization temperature

[0196] The crystallization temperature is determined according to ISO 11357-3:2013 by differential scanning calorimetry (DSC) during cooling at a rate of 20°C / min.

[0197] The tested compositions also include the following compounds:

[0198] A primary phenolic antioxidant sold under the trade name Irganox 245® by BASF (CAS No.: 36443-68-2),

[0199] A secondary phosphite antioxidant sold under the trade name Irgafos 168® by BASF (CAS No. 31570-04-4),

[0200] A mixture of dyes sold under the trade name 338160 ORA LLDPE AO Smartbatch by Avient comprising 28% pigments,

[0201] A PA6 homopolymer sold under the name Domamid H24 by Domo.

[0202] A PA6.6 homopolymer sold under the name Radilon A 42K by Radici

[0203] The following compositions are prepared by melt mixing the various raw materials in a 26 mm diameter co-rotating twin-screw extruder. The products are extruded at a flow rate of 16 kg / h, at a temperature of 250°C and with a screw speed of 250 rpm. At the machine outlet, the products are cooled by passing through a water tank and then granulated. These products are finally vacuum dried for 8 hours at 80°C. The formulations of the compositions are shown in Table 2 below; the contents in the table are indicated as a percentage by weight relative to the total weight of the composition. table 2 Sample preparation

[0204] From these compositions, plates (60x60x1 mm) and ISO 527-1 A dumbbells are injected at a temperature of 260°C. Measurement of mechanical and chemical properties

[0205] The tensile mechanical properties are measured according to ISO 527-1:2012 on dry samples. The machine used is an Instron 5966 with a crosshead speed of 50 mm / min.

[0206] Resistance to de-icing salts is measured according to EN 16811-1:2016 on a 1 mm thick plate.

[0207] The results are presented in Table 3. Table 3 Measurement of optical and electrical properties:

[0208] Dielectric strength is measured according to IEC 60243-1:2013 on a 1 mm thick plate at 25°C.

[0209] The colorimetric properties of the samples are measured in the CIELab system, as defined in ISO 11664-4:2008, using a Konica Minolta CM-36dGV spectrophotometer in reflectance mode with a D65 illuminant, an incidence angle of 10° and an aperture of 8mm and specular component included.

[0210] In this L* a* b* system, L* represents brightness, a* indicates the green / red color axis and b* the blue / yellow color axis. The higher the value of L*, the lighter or less intense the color. Conversely, the lower the value of L*, the darker or more intense the color. The higher the value of a*, the redder the shade and the higher the value of b*, the more yellow the shade. The results are presented in Table 4 Table 4 Evaluation of color variation

[0211] To perform aging tests on copper, samples are prepared by compression. A 1 mm thick plate, previously dried, is placed on a 3 mm thick copper plate. This assembly is placed in the center of a 4 mm thick frame and subjected to compression in a press at 220 ° C. The press plates are placed in contact with the sample for 90 seconds without applying pressure. Then, a pressure of 50 bar is applied. for 60s. Finally, the assembly is cooled for 2 min while maintaining a pressure of 30 bar.

[0212] These copper structures covered with the compositions as well as the plates alone manufactured with each of the compositions are aged at 150°C for 240 hours in a ventilated oven.

[0213] The colorimetric properties of aged product surfaces are measured in the CIELab system, as defined in ISO 11664-4:2008, using a Konica Minolta CM-36dGV spectrophotometer in reflectance mode with a D65 illuminant, an angle of incidence of 10° and an aperture of 8mm and specular component included.

[0214] The evolution of the color of the samples during aging expressed by the AE parameter. This is calculated according to the following equation:

[0215] In this equation, L*, a* and b* represent the values ​​measured on the aged plate, at t = 240h and Lo*, ao* and bo* represent the values ​​measured on the unaged plates. The higher the value of AE, the more the color has evolved during aging, illustrating the instability of the composition.

[0216] The results of AE values ​​are shown in Table 5. Table 5

[0217] The results show that the compositions according to the invention have good mechanical, electrical and chemical properties and exhibit color stability over time. The dielectric strength of each of compositions 1 to 4 after aging at 150°C for 240 hours in a ventilated oven remains greater than 10kV / mm. Example 2 - Intermediate layer of adhesion primer Preparation of the compositions

[0218] Compositions according to the invention were prepared using the compounds of example 1 and in particular PA 11 A and PA 12 A in order to obtain compositions 1 and 2 of table 2 (example 1). Preparation of coated metal bars

[0219] The following adhesion primer is used: Epoxy acrylate primer sold under the trade name Primgreen LAT 12035 by Arkema.

[0220] It is applied by dipping a 3mm thick copper plate into the adhesion primer composition followed by a step crosslinking at 300°C for 10 minutes. The thickness of the primer layer is 10 μm.

[0221] Representative structures of the invention are prepared by heat bonding: Composition 1 or 2 (1 mm) on copper plate (3 mm) with or without primer. This assembly, surrounded by a 4 mm thick frame, is compressed in a press at 220 ° C. The press plates are brought into contact with the superimposed layers for 90 s without applying pressure. Then, a pressure of 50 bar is applied for 60 s. Finally, the assembly is cooled for 2 min while maintaining a pressure of 30 bar. The comparative examples are prepared in the same way without an intermediate layer. The structures are presented in Table 6 below: Table 6 Evaluation of structures Evaluation of color variation

[0222] The copper structures covered with the compositions are aged at 150°C for 240 hours in a ventilated study.

[0223] The colorimetric properties of aged product surfaces are measured in the CIELab system, as defined in ISO 11664-4:2008, using a Konica Minolta CM-36dGV spectrophotometer in reflectance mode with a D65 illuminant, an angle of incidence of 10° and an aperture of 8mm and specular component included.

[0224] Color aging corresponds to the color variation between the unaged plate, i.e. at t = 0 and the plate aged at 150°C at t = 240h. This variation is measured by the AE according to the equation [Math 5] described in example 1.

[0225] The higher the AE value, the more the color has changed during aging, illustrating the instability of the composition. The results are given in Table 7 below: Table 7 Evaluation of salt spray corrosion resistance

[0226] Salt spray resistance of structures is assessed according to ISO 12944-6:2018. A NaCl solution at a concentration of 50 g / L is sprayed onto the surface of the sample at 35°C for 240 hours. The result of this test depends on whether adhesion to the metal / polymer interface is maintained or whether it is debonded.

[0227] The results of the evaluation tests are given in Table 8 below: Table 8

[0228] The examples show that the structures according to the invention have good mechanical properties and exhibit color stability over time and resistance to corrosion. Example 3 - Metallic Intermediate Layer

[0229] Compositions according to the invention were prepared using the compounds of example 1 and in particular PA 11 A and PA 12 A in order to obtain compositions 1 and 2 of table 2 (example 1). Preparation of coated metal bars

[0230] 2 metal plates are used: - the 3 mm thick pure copper plate - a 3mm thick copper plate covered with a 1 pm layer of nickel.

[0231] Representative structures of the invention are prepared by heat bonding: Composition A or B (1 mm) / copper plate with or without nickel coating

[0232] This assembly, surrounded by a 4 mm thick frame, is compressed in a press at 220°C. The press plates are brought into contact with the superimposed layers for 90s without applying pressure. Then, a pressure of 50 bar is applied for 60s. Finally, the assembly is cooled for 2 min while maintaining a pressure of 30 bar. Table 9 Evaluation of structures: Evaluation of color variation

[0233] The copper structures covered with the compositions are aged at 150°C for 240 hours in a ventilated study.

[0234] The colorimetric properties of aged product surfaces are measured in the CIELab system, as defined in ISO 11664-4:2008, using a Konica Minolta CM-36dGV spectrophotometer in reflectance mode with a D65 illuminant, an angle of incidence of 10° and an aperture of 8mm and specular component included.

[0235] Color aging corresponds to the color variation between the unaged plate, i.e. at t = 0 and the plate aged at 150°C at t = 240h. This variation is measured by the AE according to the equation [Math 5] described in example 1.

[0236] The higher the AE value, the more the color has changed during aging, illustrating the instability of the composition. The results are given in Table 10 below:

[0237] The examples show that the structures according to the invention have good mechanical properties and exhibit color stability over time. Example 4 - Polyolefin Intermediate Layer

[0238] Compositions according to the invention were prepared using the compounds of example 1 and in particular PA 11 A and PA 12 A in order to obtain compositions 1 and 2 of table 2 (example 1).

[0239] Preparation of coated metal bars The following intermediate layers are used: Intermediate layer 1: 200 µm thick film of functionalized polyethylene sold under the trade name Orevac IM300 by SK Functional Polymer Intermediate layer 2: 200 pm thick film of functionalized polypropylene sold under the trade name Orevac CA100 by SK Functional Polymer

[0240] Representative structures of the invention are prepared by heat bonding: Composition A or B / intermediate layer / copper

[0241] This assembly, surrounded by a frame of identical thickness to the total assembly, is compressed in a press at 220°C. The press plates are brought into contact with the superimposed layers for 90s without applying pressure. Then, a pressure of 50 bar is applied for 60s. Finally, the assembly is cooled for 2 min while maintaining a pressure of 30 bar. The comparative examples are prepared in the same way without an intermediate layer. Table 11 Evaluation of color variation

[0242] The copper structures covered with the compositions are aged at 150°C for 240 hours in a ventilated study.

[0243] The colorimetric properties of aged product surfaces are measured in the CIELab system, as defined in ISO 11664-4:2008, using a Konica Minolta CM-36dGV spectrophotometer in reflectance mode with a D65 illuminant, an angle of incidence of 10° and an aperture of 8mm and specular component included. The evolution of the color of the samples during aging expressed by the parameter AE. This is calculated according to the equation [Math 5] described in example 1.

[0244] The higher the AE value, the more the color has evolved during aging, illustrating the instability of the composition.

[0245] The results of the evaluation tests are given in Table 12 Table 12 Evaluation of adhesion at the metal / polymer interface:

[0246] Adhesion at the copper / polyolefin interface is measured by a peel test using a dynamometer according to standard NF EN 28510-1:2014. A 7 mm wide polymer strip is cut using a die cutter within the exemplified structures. One end of this strip is fixed to the moving part of the dynamometer while the rest of the sample is held horizontally. Peeling is achieved by the vertical movement of the moving part of the dynamometer at a speed of 50 mm / min. The force sensor records the adhesion force opposing this peeling.

[0247] The results of the evaluation tests are given in Table 13 Table 13

[0248] The examples show that the structures according to the invention have good mechanical properties and exhibit color stability over time and good adhesion of the coating layer.

Claims

Claims

1. [Electrically insulating composition for covering an electricity transmission component comprising: -predominantly at least one polyamide, the polyamide(s) having: - a difference, expressed as an absolute value, between the total acidity of the polyamide(s) or the total basicity of the polyamide(s) less than 70, the total basicity and the total acidity being measured by potentiometry and - a total basicity measured by potentiometry of less than 60 peq / g, and the composition comprising mainly at least one polyamide having a number of carbon atoms per nitrogen atom greater than 6.5 and - at least one coloring matter characterized in that the color of the composition is different from a black color.

2. Composition according to claim 1, characterized in that the composition comprises from 60 to 98% by weight of said at least one polyamide.

3. Composition according to claim 1 or 2 characterized in that said at least one polyamide is an aliphatic or cycloaliphatic polyamide.

4. Composition according to any one of the preceding claims, characterized in that the polyamide(s) have an inherent viscosity measured according to standard ISO 307:2007 greater than 1.

1.

5. Composition according to any one of claims 1 to 3, characterized in that the polyamide(s) have an enthalpy of fusion measured by DSC during the second heating according to standard ISO 11357-3:2013 strictly greater than 20 J / g.

6. Composition according to any one of the preceding claims, characterized in that the polyamide(s) have a crystallization temperature measured by DSC during the second heating according to standard ISO 11357-3:2013 strictly less than 180°C.

7. Composition according to any one of the preceding claims, characterized in that the polyamide(s) have a total acidity of less than 60 peq / g.

8. Composition according to any one of the preceding claims, characterized in that the majority polyamide is chosen from a PA11, PA12, PA1010, PA 1012, PA 610, PA 612, PA 516, PA613, PA912, PA6 / 11, PA6 / 12, PA, 11 / 12, PA 6 / 11 / 12, PA 6 / 66 / 12, PA 6 / 1010, PA 6 / 1012, PA 6 / 1010 / 1012, PA 6 / 1012 / 12, PA 6 / 66 / 11 / 12, PA 6 / 1010 / 1012 / 1014 alone or as a mixture, more particularly PA11, PA12, PA1010, PA 1012, even more preferably PA11 or PA12, preferably PA ... PA11 .

9. Composition according to any one of the preceding claims, characterized in that the coloring matter is a mixture of at least two pigments.

10. Composition according to any one of the preceding claims, characterized in that the coloring matter comprises titanium dioxide, tin oxide, zinc oxide and their mixture.

11. Composition according to the preceding claim, characterized in that the coloring matter comprises titanium dioxide, tin oxide, zinc oxide and at least two additional pigments.

12. Composition according to any one of the preceding claims, characterized in that the coloring matter is included in a content ranging from 0.5 to 10% by weight, preferably between 1 and 5% by weight relative to the total weight of the composition.

13. Composition according to any one of the preceding claims, characterized in that it comprises at least one antioxidant.

14. Use of a composition as defined in claims 1 to 13, for coating an electricity transport component, preferably an electric battery interconnection bar.

15. Electricity transmission component comprising: - an electricity transport component having a metallic surface and -a coating layer in a composition as defined in any one of claims 1 to 13.

16. Component according to claim 15, characterized in that the metal surface is made of copper, copper alloy, aluminum or aluminum alloy.

17. Component according to claim 15 or 16, characterized in that it is an interconnection bar.

18. A method of preparing an electricity transport component comprising a step of covering the metal surface of the electricity transport component with a composition as defined in one of claims 1 to 13.

19. Method according to the preceding claim, characterized in that it comprises a step of pre-treatment of the metal surface by degreasing and / or a singeing step and / or a pre-heating step.]

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