COLORED POLYAMIDE COMPOSITION FOR COATING ELECTRICITY TRANSMISSION COMPONENTS

Abstract

COLORED POLYAMIDE COMPOSITION FOR COATING ELECTRICAL TRANSPORT COMPONENTS The invention relates to an electrically insulating composition for coating an electrical transport component comprising: - predominantly at least one polyamide, the polyamide(s) having: - a difference, expressed in absolute value, between the total acidity of the polyamide(s) and the total basicity of the polyamide(s) less than 70 and - a total basicity less than 60 µeq / g, and the composition predominantly comprising at least one polyamide having a number of carbon atoms per nitrogen atom greater than 6.5 and - at least one coloring material and its use for coating an electrical transport component, preferably an electric battery interconnection bar.

Description

Title of the invention: 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 or busbars in English) are present to circulate high-intensity current inside and outside the batteries. These bars must be covered by an insulating coating and resistant to mechanical stress and aging.

[0003] Several methods exist for preparing busbars. The main one is the extrusion of the polymer composition around the central metal strip. Coating processes using powder, dipping or electro-spray can also be used. These structures are then cut and bent (at room temperature) to adopt 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 engine, self-heating during current flow, in particular 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 engine, for 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, the coloring of which 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 plasticity threshold of the material is therefore crucial. Low threshold stresses and a high threshold elongation are sought. The deformation levels of these coatings remain low but the material must still have an elongation at break > 50%, preferably greater than 100%, 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 advantageous 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 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] Document US 2021 / 0253854 and document KR101977321 disclose a composition based on polyamide and at least one pigment system. However, it turns out that the disclosed compositions are not satisfactory from a mechanical point of view. Furthermore, the evolution of the color 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] The invention also relates to its use for covering an electricity transmission component.

[0014] The invention also relates to an electricity transmission component comprising: - an electricity transport component having a metallic surface and - a coating layer made of a composition as defined above.

[0015] Finally, the invention relates to a method for preparing an electricity transmission component.

[0016] 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 electrical insulation properties have been preserved after aging. Furthermore, the composition according to the invention has 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 has good chemical resistance, i.e. good resistance to de-icing salt. Finally, the electrical component covered with said composition remains easy to strip.

[0017] 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 standard ISO 11357-3:2013 strictly lower than 180°C; - the polyamide(s) have a total acidity of less than 60 peq / g; -the polyamide is chosen from a PAU, PA 12, PA 1010, 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 PAU, PA 12, PA 1010, PA 1012, even more preferably PA11 or PA 12, 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

[0018] Other characteristics, aspects, objects and advantages of the present invention will appear even more clearly on reading the description which follows.

[0019] The nomenclature used to define polyamides is described in the standard ISO 1874-1:2011 "Plastics - Polyamide (PA) materials for molding and extrusion - Part 1: Designation", in particular on page 3 (tables 1 and 2) and is well known to those skilled in the art. Thus, PA11 means that it is obtained by polycondensation of amino-11-undecanoic 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).

[0020] It is further specified that the expressions "between... and..." and "from... to..." used in the present description must be understood as including each of the limits mentioned.

[0021] The word "polyamide" covers both homopolyamides and copolyamides.

[0022] The invention is now described in more detail and in a non-limiting manner in the following description. Composition

[0023] The composition according to the invention is an electrically insulating composition for covering an electricity transport 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.

[0024] By electrically insulating, we mean in the sense of the present invention 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 standard IEC 60243-1:2013.

[0025] The composition mainly comprises at least one polyamide, that is to say one or more polyamides.

[0026] By predominantly, it is meant within the meaning 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. This or these polyamides constitute the matrix of the composition.

[0027] 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%.

[0028] Polyamide

[0029] In the case of a homopolyamide of type PA-XY, 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 structure XaYa / XbYb, 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.

[0030] 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.

[0031] For the purposes of the present invention, the term “majority” 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. 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 majority, that is to say that it must represent at least 50% by weight relative to the total weight 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%.

[0033] In other words, the presence of other polyamides is not excluded. However, it is important that the highly carbon-containing polyamides are in the majority within the composition.

[0034] 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 (Ca diamine) (Cb diacid) unit, 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.

[0035] The polyamide can be obtained by polycondensation of at least one lactam chosen from pyrrolidinone, 2-piperidinone, enantholactam, caprylolactam, pelar-golactam, decanolactam, undecanolactam, and lauryllactam.

[0036] 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).

[0037] 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.

[0038] The unit (diamine in Ca) 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), nona-nediamine (a=9), decanediamine (a= 10), undecanediamine (a= 11), dodeca-nediamine (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).

[0039] 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.

[0040] Advantageously, the diamine X used is C10 to C12, in particular chosen from 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine.

[0041] 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), do-decanedioic 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).

[0042] 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.

[0043] Advantageously, the polyamide present in the composition according to the invention is aliphatic.

[0044] Advantageously, the polyamide present in the composition according to the invention is chosen from PAU, 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.

[0045] 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.

[0046] 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) (Cb diacid) unit, with Ca and Cb being as defined above.

[0047] More particularly, the composition mainly comprises PAU, PA12, PA1010, PA 1012, even more preferably PAU or PA12, preferably PAU.

[0048] PA11 has the advantage of being manufactured from raw materials of plant origin. Plant materials can be grown in large quantities, depending on demand, over most of the globe and can be bio-sourced. A bio-sourced raw material is a natural resource, animal or plant, whose stock can be replenished over a short period on a human scale. In particular, this stock must be able to be renewed as quickly as it is consumed.

[0049] The basic raw material of PA11 is castor oil, extracted from the plant of the same name (the common castor oil plant), from castor beans. PA11 is obtained by polycondensation of amino-11-undecanoic acid. Total acidity and total basicity

[0050] The polyamide(s) present in the composition according to the invention has(have) 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.

[0051] 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.

[0052] When the composition comprises a mixture of polyamides, the acidity and basicity are measured on the mixture of polyamides. The difference is therefore expressed for the mixture of polyamides.

[0053] The polyamide(s) present in the composition according to the invention also have a total basicity strictly less than 60 peq / g, preferably less at 50 pcq / g. and ideally less than 40 pcq / g.

[0054] 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.

[0055] Acidity and basicity are measured by potentiometry.

[0056] The acidity is measured according to the following method. A sample of polyamide is dissolved in benzyl alcohol. Then, this sample is assayed by potentiometry with a 0.02N tetrabutylammonium hydroxide solution.

[0057] The basicity is measured according to the following method. A sample of polyamide is dissolved in metacresol. Then, this sample is assayed by potentiometry with a 0.02N perchloric acid solution.

[0058] 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.

[0059] According to a preferred embodiment, the composition according to the invention mainly comprises PAU, 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 as an absolute value, between its total acidity and its total basicity strictly less than 50, ideally less than 30.

[0060] 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 as an absolute value, between its total acidity and its total basicity strictly less than 30.

[0061] Preferably, the polyamide(s) present in the composition do not comprise a chain limiter. Inherent viscosity

[0062] 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.

[0063] The measurement is carried out at 20°C on a 75 mg sample at a concentration of 0.5% (m / m) in m-cresol.

[0064] When the composition comprises a mixture of polyamides, the viscosity is measured on the mixture of polyamides. Enthalpy of fusion

[0065] Preferably, the polyamide(s) have an enthalpy of fusion greater than 20J / g, preferably greater than 30 J / g and ideally greater than 40 J / g.

[0066] The enthalpy of fusion is measured by DSC (differential scanning calorimetry measurement) according to ISO 11357-3: 2013 (2nd DSC heating at 20°C / min according to ISO 11357).

[0067] When the composition comprises a mixture of polyamides, the enthalpy of fusion is measured on the mixture of polyamides. Crystallization temperature

[0068] Preferably, the polyamide blend(s) have a crystallization temperature of less than 180°C, preferably less than 160°C.

[0069] The crystallization temperature is measured by DSC (differential scanning calorimetry) according to ISO 11357-3:2013 (2nd DSC heating at 20°C / min according to ISO 11357).

[0070] When the composition comprises a mixture of polyamides, the crystallization temperature is measured on the mixture of polyamides.

[0071] The coloring matter

[0072] 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.

[0073] 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, indigo-derived dyes, triarylmethane dyes, chlorine dyes and polymethine dyes.

[0074] By "pigment" is meant all pigments providing color to a polymer composition. Their solubility in water at 25°C and at atmospheric pressure (760 mmHg) is less than 0.05% by weight, and preferably less than 0.01%. The pigments which can be used are in particular chosen 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.

[0075] The pigments may be of natural origin or not. These pigments may be in the form of powder or pigment paste. They may be coated or uncoated. The pigments may, for example, be chosen from mineral pigments, organic pigments and their mixtures.

[0076] By mineral pigment is meant any pigment which 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), ochre brown (clay (especially kaolinite) and limonite), yellow ochre (clay (especially kaolinite) and goethite); titanium dioxide, possibly surface-treated; zirconium or cerium oxides; zinc, iron (black, yellow or red), or chromium oxides; manganese violet, ultramarine blue, chromium hydrate and ferric blue; metallic powders such as aluminum powder, copper powder.

[0077] Mention may also be made of 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, provided that these compounds provide color or white to the composition under the conditions in which they are used.

[0078] The pigment may be an organic pigment. By "organic pigment" is meant any pigment that meets the definition of the Ullmann encyclopedia in the organic pigment chapter.

[0079] 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, qui-nacridone, perinone, perylene, diketopyrrolopyrrole, indigo, thioindigo, dioxazine, triphenylmethane, quinophthalone.

[0080] 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 CI 12085, 12120, 12370, 12420, 12490, 14700, 15525, 15580, 15620, 15630, 15800, 15850, 15865, 15880, 26100, 45380, 45410, 58000, 73360, 73915, 75470.

[0081] Advantageously, the pigment is chosen from the pigments CI Pigment Orange 82 [CAS No. 2170864-77-2] and CI Pigment Yellow 216 [CAS No. 817181-98-9]. Pigment Orange 82 can be obtained, for example, under the name Sicopal® Orange K2430 from Sun Chemical, Ludwigshafen, Germany. Pigment Yellow 216 can be obtained, for example, under the name Orange 10P340 from Shepherd, Gent, Belgium.

[0082] Among the colorants, mention may be made of carminic acid. Mention may also be made of the colorants known under the following names: D & C Red 21 (CI 45 380), D & C Orange 5 (CI 45 370), D & C Red 27 (CI 45 410), D & C Orange 10 (CI 45 425), D & C Red 3 (CI 45 430), D & C Red 4 (CI 15 510), D & C Red 33 (CI 17 200), D & C Yellow 5 (CI 19 140), D & C Yellow 6 (CI 15 985), D & C Green (CI 61 570), D & C Yellow 1 O (CI 77 002), D & C Green 3 (CI 42 053), D & C Bine 1 (CI 42 090).

[0083] The coloring material 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.

[0084] Preferably, the composition according to the invention comprises at least one coloring material leading to an orange color.

[0085] 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.

[0086] Advantageously, the coloring material is a mixture of at least two pigments. More preferably, the coloring material comprises titanium dioxide, tin oxide, zinc oxide and their mixture. Even more preferably, the coloring material comprises titanium dioxide, tin oxide, zinc oxide and at least two additional pigments, preferably leading to the orange color.

[0087] 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.

[0088] 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.

[0089] Additives

[0090] 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.

[0091] Antioxidants

[0092] Preferably, the composition according to the invention comprises at least one antioxidant

[0093] By way of 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 Ciba-BASF), a phosphite antioxidant (for example, irgafos® 126 or Irgafos® 168 from Ciba-BASF) and possibly other stabilizers such as HALS, which stands for Hindered Amine Light Stabilizer (for example, Tinuvin® 770 from Ciba-BASF), a UV stabilizer (for example, Tinuvin® 312 from Ciba), a phosphorus-based stabilizer. It is also possible to use amine antioxidants such as Naugard® 445 from Crompton or polyfunctional stabilizers such as Nylostab® S-EED from Clariant.

[0094] 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.

[0095] In another embodiment, the composition defined above has a threshold stress < 60 MPa, preferably < 50 MPa,

[0096] In yet another embodiment, the composition defined above has a threshold elongation > 3%, advantageously > 4% measured according to the ISO 527-1 / 2:2012 standard.

[0097] 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.

[0098] 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.

[0099] 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 150°C.

[0100] 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

[0101] 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 interconnect bar.

[0102] All the characteristics defined above are valid for this use.

[0103] 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.

[0104] A material that is too rigid forms cracks or “waves” which are prohibitive for the application. Electricity transmission component

[0105] The invention also relates to an electricity transport component comprising: - an electricity transport component having a metallic surface and - a coating layer made of a composition as defined above.

[0106] Preferably, the metal surface is copper, copper alloy, aluminum or aluminum alloy, preferably copper and copper alloy.

[0107] 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.

[0108] According to a particular embodiment of the invention, the coating layer is in direct contact with the metal surface.

[0109] According to another embodiment, the electricity transport component comprises an intermediate layer located between the metal surface and the coating layer.

[0110] According to another embodiment, the coating layer made 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.

[0111] Preferably, the electricity transport component is an electrical or electronic component cover, a control device, a connector, a battery relay, an electrical box, an electrical terminal or a cable.

[0112] Preferably, the electricity transport component is an interconnection bar (busbar in English).

[0113] In one embodiment, said interconnection bar is located inside and / or outside electric batteries, in particular electric batteries of vehicle, especially a motor vehicle. It can, for example, be immersed in a coolant.

[0114] Process for preparing the electricity transmission component

[0115] According to yet another aspect, the present invention relates to a method for preparing an electricity transport component comprising a step of covering the metal surface of the electricity transport component with a composition as defined above.

[0116] 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.

[0117] The covering 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.

[0118] Preferably, the preparation process does not include a step of powder coating said composition on an electric battery interconnection bar.

[0119] It is possible for the metal surface to undergo a pre-treatment 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 pre-heating step.

[0120] Preferably, the electricity transport component is an electric battery interconnection bar.

[0121] This metal bar can be solid. But it can also be made up of a multitude of braided metal filaments, which gives it great flexibility.

[0122] All the characteristics defined above are valid for the method.

[0123] Other aims and advantages of the present invention will appear on reading the following examples given without any limitation being implied. EXAMPLES Preparation of the compositions

[0124] Compositions according to the invention and comparative compositions were prepared using the following compounds.

[0125] The polyamide according to the invention, noted 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, maintaining under autogenous pressure for 30 min. 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 2 hours up to 1 bar, raising the temperature to 255°C. A sweep nitrogen 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.

[0126] 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 under autogenous pressure for 1 h. 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 75 minutes up to 10 bars 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, the stirring is stopped and the melt extruded under a pressure of 10 bars. The rush is cooled in a water bath, then granulated.

[0127] 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 under autogenous pressure for 90 minutes. 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 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.

[0128] 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 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 while 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 rod is cooled in a water bath and then granulated.

[0129] 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 throughout 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, the stirring is stopped and the melt extruded under a pressure of 10 bars. The rod is cooled in a water bath, then granulated.

[0130] A blend of polyamides is prepared by blending the polyamides in the molten state. This blend consists of 84% by weight of PA 11 A and 16% by weight of PA 11 B.

[0131] The tested polyamides and the polyamide blend have the characteristics indicated in Table 1 below: PA 11 A PAU B PA 11 C PA 12 A PA 12 B Mixture Total acidity (geq / g) 48 66 21 32 9 51 Total acidity (geq / g) 57 47 100 35 81 55 A 9 19 79 3 73 4 viscosity 1.42 1.39 1.02 1.58 1.05 1.40 AHf(J / g) 65 63 66 67 75 64 TCnst(°C) 152 140 154 153 147 153 Table 1 Measurement of total basicity

[0132] The basicity is measured according to the following method. 1g of polyamide is dissolved in 80 mL of hot metacresol. The sample is then cooled. Then, it is dosed by potentiometry using a Metrohm titrator (888 or 716) with a combined pH electrode, by a 0.02N perchloric acid solution in acetic acid. The potential curve as a function of volume gives a jump with an equivalent volume from which the total basicity is calculated, using the following formula:

[0133] [Math.l] Total basicity (meq / g) = —Hn--- 1 in which Veq denotes the equivalent volume obtained by potentiometric dosing, [HC1O4] denotes the concentration of the perchloric acid solution, i.e. 0.02 N, m denotes the mass of the sample, i.e. 1g. Total acidity measurement

[0134] The acidity is measured according to the following method. 1 g of polyamide is dissolved in 80 mL of hot benzyl alcohol. The sample is then cooled. Then, it is dosed by potentiometry using a Metrohm titrator (888 or 716) with a combined pH electrode, by a 0.02N tetrabutylammonium hydroxide solution. The potential curve as a function of volume gives a jump with an equivalent volume from which the total acidity is calculated using the following formula:

[0135] [Math.2] Total acidity (meq g) = in which Veq denotes the equivalent volume obtained by potentiometric dosing, [TBAOH] denotes the concentration of the tetrabutylammonium hydroxide solution, i.e. 0.02 N, m denotes the mass of the sample, i.e. 1g.

[0136] Calculation of the difference between total acidity and basicity

[0137] 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.

[0138] For example, for PA 11 A:

[0139] [Math.3] d = |57-48|=9 Measurement of inherent viscosity

[0140] 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:

[0141] [Math 4]

[0142] Inherent viscosity = ln(ts / t0) x 1 / C, with C = m / px 100, in which ts is 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

[0143] The enthalpy of fusion is determined according to ISO 11357-3:2013 by DSC during the second heating. Measurement of crystallization temperature

[0144] 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.

[0145] The tested compositions also include the following compounds:

[0146] A phenolic-type primary antioxidant sold under the trade name Irganox 245® by BASF (CAS No.: 36443-68-2),

[0147] A secondary phosphite antioxidant sold under the trade name Irgafos 168® by BASF (CAS No.: 31570-04-4),

[0148] A mixture of dyes sold under the trade name 338160 ORA LLDPE AO Smartbatch by Avient comprising 28% pigments,

[0149] A PA6 homopolymer sold under the name Domamid H24 by Domo.

[0150] A PA6.6 homopolymer sold under the name Radilon A 42K by Radici

[0151] 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 dried under vacuum for 8 hours at 80°C. The formulations of the compositions are shown in Table 2 below. 1 2 3 4 5 6 7 8 Inv Inv Inv Comp Comp Comp Comp Comp PAU A 95 - 80 - - - - - PAU B - - 15 95 - - - - PAU C - - - - 95 - - - PA12A - 95 - - - - - - PA12B - - - - - 95 - - PA6 - - - - - - 95 - PA66 - - - - - - - 95 Irganox 245 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 Irgafos 168 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Colorant 4 4 4 4 4 4 4 4 Table 2 Sample preparation

[0152] From these compositions, plates (60x60xlmm) and ISO 527-1A dumbbells are injected at a temperature of 260°C. Measurement of mechanical and chemical properties

[0153] 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.

[0154] Resistance to de-icing salts is measured according to EN 16811-1:2016 on a 1 mm thick plate.

[0155] The results are presented in Table 3. 1 2 3 4 5 6 7 8 Inv Inv Inv Comp Comp Comp Comp Comp Comp Threshold stress (MPa) 41 45 41 40 44 43 75 85 Resistance to de-icing salt Yes Yes Yes Yes Yes Yes No No Table 3

[0156] Measurement of optical and electrical properties:

[0157] The dielectric strength is measured according to IEC 60243-1:2013 on a 1 mm thick plate at 25°C.

[0158] 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 angle of incidence of 10° and an aperture of 8mm and specular component included.

[0159] 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 very 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.

[0160] The results are presented in Table 4 1 2 3 4 5 6 Inv Inv Inv Comp Comp Comp Dielectric strength (kV / mm) 27 28 27 27 28 28 L* 62.5 62.1 62.7 62.1 62.3 62.2 a* 33.6 33.4 34.4 34.3 33.7 33.7 b* 36.5 37.7 38 37 37.5 38.4 Table 4 Evaluation of color variation

[0161] To carry out aging tests on copper, the 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 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.

[0162] 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.

[0163] The colorimetric properties of the 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.

[0164] The evolution of the color of the samples during aging expressed by the parameter AE. This is calculated according to the following equation:

[0165] At 17 k T* / T / . AE- E - L0J +( a- üq) - b Q )

[0166] In this equation, L*, a* and b* represent the values ​​measured on the aged plate, at t = 240h and Lo*, a0* and b0* 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.

[0167] The results of the AE values ​​are shown in Table 5. 1 Inv 2 Inv 3 Inv 4 Comp 5 Comp 6 Comp AE on an aged composition plate (1 mm) 6 5 6 14 24 16 AE on a copper plate covered with the aged composition 15 13 17 39 45 41 (4 mm) Table 5

[0168] The results show that the compositions according to the invention have good mechanical, electrical and chemical properties and exhibit color stability over time.

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) of less than 70 and - a total basicity of less than 60 peq / g, and the composition comprising predominantly at least one polyamide having a number of carbon atoms per nitrogen atom of greater than 6.5 and - at least one coloring matter.

2. Composition according to claim 1, characterized in that the polyamide(s) have an inherent viscosity measured according to standard ISO 307:2007 greater than 1.

1.

3. Composition according to claim 1 or 2, 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.

4. 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.

5. 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.

6. Composition according to any one of the preceding claims, characterized in that the majority polyamide is chosen from a PAU, 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 PAU, PA12, PA1010, PA 1012, even more preferably PAU or PA 12, preferably PAU.

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

8. 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.

9. 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.

10. 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.

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

12. Use of a composition as defined in claims 1 to 11, for coating an electricity transport component, preferably an electric battery interconnection bar.

13. An electricity transport component comprising: - an electricity transport component having a metallic surface and - a coating layer of a composition as defined in any one of claims 1 to 11.

14. Component according to claim 13, characterized in that the metal surface is made of copper, copper alloy, aluminum or aluminum alloy.

15. Component according to claim 13 or 14, characterized in that it is an interconnection bar.

16. 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 11.

17. 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.