Power transmission components, especially for batteries.

Abstract

The present invention relates to a power transmission component comprising a metal surface, wherein the metal surface is coated over its entire surface with a coating layer having a color other than black, made from an electrically insulating composition comprising at least one polyamide having more than 6.5 carbon atoms per nitrogen atom and at least one colorant, the intermediate layer being positioned between the metal surface and the coating layer of the power transmission component. The present invention further relates to a method for preparing a power transmission component.

Description

Technical Field

[0001]

[0001] The present invention relates to power transmission components, and more particularly to colored bus bars, especially for batteries.

Background Art

[0002]

[0002] In the field of electric vehicles, connectors called bus bars (interconnect bars) are used to pass high currents inside and outside batteries. These bars need to be covered with an insulating coating that is resistant to mechanical stress and aging.

[0003]

[0003] There are several methods for manufacturing bus bars. The main one is extrusion of a polymer composition around a central metal strip. Powder coating methods, dip coating methods or electrospray coating methods can also be used. These structures are cut and bent (at room temperature) to obtain the shape required for the vehicle layout.

[0004]

[0004] For safety reasons, these bars also require a unique color that represents the current flowing through the bar. Therefore, it is essential that this color remains stable over a long period of time regardless of the temperature to which the bar is exposed. Specifically, external conditions, proximity to the engine, and particularly self-heating when current flows during battery charging, are factors that affect the color of the coating over time. If the color changes over time, there may be uncertainty about the voltage of the current flowing through the bar, which may lead to accidents during, for example, engine maintenance or repair. Therefore, it is essential that the color is stable despite harsh environmental conditions.

[0005]

[0005] A technical challenge related to the application of battery busbars is to form a thin polymer layer that does not change color over time while maintaining high flexibility to accommodate deformation of the busbar. If the material is too rigid during bending, cracks will form on the outer surface and buckling will occur on the inner surface, and this buckling will appear as "waves" or "beads," which are unacceptable phenomena in this application.

[0006]

[0006] Therefore, the behavior of the material at the plastic threshold is extremely important. Low stress and high elongation at the threshold are desirable. The deformation level of these coatings remains low, but the elongation at fracture of the material must still be >50%, preferably over 100%, and more preferably over 200%. Excellent wear resistance is also required for this application.

[0007]

[0007] Furthermore, depending on the position of these components within the engine, it may be advantageous for their composition to be resistant to antifreeze salts.

[0008]

[0008] The coating must also function 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 even during accelerated thermal aging, which may reach up to 130°C, and especially up to 150°C.

[0009]

[0009] Finally, the rheological properties of the alloy need to be suitable for extruding a thin polymer layer of about 0.5 mm.

[0010]

[0010] Furthermore, the prior art does not provide information on the combinations that should be used in the formulation to simultaneously achieve the flexibility and color stability required for battery busbar applications.

[0011]

[0011] U.S. Patent Application No. 2021 / 0253854 and Korean Patent No. 101977321 disclose compositions based on polyamide and at least one pigment system. However, the disclosed compositions have been found to be unsatisfactory from a mechanical standpoint. Furthermore, the color changes of these products during maturation have not been documented.

[0012] Summary of the Invention

[0012] The present invention relates to a power transmission component, which includes a metal surface, wherein the metal surface extends over its entire surface, - An intermediate layer made of inorganic materials, and - A coating layer made from an electrically insulating composition mainly comprising at least one polyamide having more than 6.5 carbon atoms per nitrogen atom, and at least one colorant. It is coated with The present invention relates to a power transmission component characterized in that the intermediate layer is positioned between the metal surface of the power transmission component and the coating layer.

[0013]

[0013] Preferably, the coating layer is characterized by having a color other than black.

[0014]

[0014] According to one embodiment, the electrical insulating composition has an L* parameter greater than 0, preferably greater than 5, preferably greater than 10, measured in reflection mode using a Konica Minolta CM-36dGV spectrophotometer in a CIELab system as defined in standard ISO 11664-4:2008 under the conditions of light source D65, incident angle 10°, aperture 8 mm, and including a specular component.

[0015]

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

[0016]

[0016] Preferably, the intermediate layer made of an inorganic material is characterized in that the material is a material other than a metal.

[0017]

[0017] Preferably, the coating layer composition contains 60% to 98% by weight of at least one polyamide.

[0018]

[0018] Preferably, the coating layer composition is characterized in that at least one polyamide is an aliphatic or alicyclic polyamide, preferably an aliphatic polyamide.

[0019]

[0019] Finally, the present invention relates to a method for manufacturing the power transmission component defined above, - A step of coating the entire metal surface of a power transmission component with an intermediate layer of inorganic material according to any one of claims 1, 4, and 5, and thereafter - A step of coating an intermediate layer of an inorganic material with the coating composition according to any one of claims 1 and 6 to 12. Regarding methods including

[0020]

[0020] The color of the composition deposited on the component according to the present invention has been observed to remain stable even after aging at high temperatures. It has also been observed that the composition maintains a certain electrical insulation property even after aging. Furthermore, the composition deposited on the component according to the present invention has good mechanical properties, with very good elongation at break, impact strength, and performance of the polymer layer when bending metal rods. Finally, the electrical component coated with the composition remains easily peelable.

[0021]

[0021] Other advantageous features of the method according to the present invention are set forth below. - The component is a bus bar. - The metal surfaces of the components are made of copper, copper alloy, aluminum, or aluminum alloy. - The intermediate layer made of inorganic material is a layer of mica, carbon fiber, or glass fiber, preferably mica. - The thickness of the intermediate layer made of inorganic material is 0.1 to 2 mm, preferably 0.15 to 1 mm. - The polyamide of the coating layer has an intrinsic viscosity of more than 1.1, measured in accordance with the standard ISO 307:2007, - The polyamide of the coating layer has a melting enthalpy of more than 20 J / g, measured by DSC during the second heating in accordance with the standard ISO 11357-3, 2013, - The polyamide of the coating layer has a crystallization temperature strictly lower than 180°C, measured by DSC during the second heating in accordance with the standard ISO 11357-3, 2013, - The polyamide of the coating layer is selected from PA11, PA12, PA1010, PA1012, PA610, PA612, PA613, PA516, PA912, PA6 / 11, PA6 / 12, PA11 / 12, PA6 / 11 / 12, PA6 / 66 / 12, PA6 / 1010, PA6 / 1012, PA6 / 1010 / 1012, PA6 / 1012 / 12, PA6 / 66 / 11 / 12 and PA6 / 1010 / 1012 / 1014, either alone or as a mixture; more specifically selected from PA11, PA12, PA1010 or PA1012, even more preferably from PA11 or PA12, preferably from PA11, - The content of the colorant ranges from 0.5% by weight to 10% by weight, preferably from 1% by weight to 5% by weight, based on the total weight of the composition, - Expressed in absolute value, the difference between the total acidity and total basicity of the polyamide in the composition of the coating layer is less than 70, and the total basicity of the polyamide is less than 60 µeq / g, - The composition of the coating layer has a total acidity of the polyamide of less than 60 µeq / g, - In the method, the intermediate layer coating step is performed by extrusion, - In the method, the intermediate layer coating step is performed by depositing a powder of the coating composition and then melting the powder.

[0022] Detailed Description

[0022] Other features, aspects, subject matters and advantages of the present invention will become more apparent upon reading the following description.

[0023]

[0023] The nomenclature used for defining polyamides is described in particular on page 3 (Tables 1 and 2) of the standard ISO 1874-1:2011 "Plastics - Polyamide (PA) molding and extrusion materials - Part 1: Designation", and is well known to those skilled in the art. Accordingly, PA11 is obtained by polycondensation of 11-aminoundecanoic acid. PA12 is obtained by polycondensation of lauryl lactam. 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]

[0024] Furthermore, it is specified that the expressions "between ... and ..." and "from ... to ... (or ...~...)" used in the present specification should be understood to include each recited limit.

[0025]

[0025] The term "polyamide" encompasses both homopolyamides and copolyamides.

[0026]

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

[0027] Power transmission components

[0027] The subject matter of the present invention is a power transmission component, preferably a busbar, the power transmission component comprising a metal surface, and the metal surface extends over the entire surface thereof, - an intermediate layer made of an inorganic material, and - a coating layer made of an electrically insulating composition mainly comprising at least one polyamide having a number of carbon atoms of more than 6.5 per nitrogen atom and at least one colorant with which the metal surface is coated, the power transmission component is characterized in that the intermediate layer is positioned between the metal surface of the power transmission component and the coating layer.

[0028]

[0028] Preferably, the coating layer is characterized in that its color is other than black as determined by the RAL method. The term "black" refers to RAL colors 2100, 6015, 7021, 8022, 9004, 9005, 9011, 9017, and 9021. RAL colors 2100, 6015, 7021, 8022, 9004, 9005, 9011, 9017, and 9021 correspond to black.

[0029]

[0029] Preferably, the intermediate layer made from an inorganic material is characterized in that the material is other than a metal layer.

[0030]

[0030] The power transmission component is preferably a high-voltage power transmission component. The term "high voltage" refers to a voltage between 400V and 1000V.

[0031] Preferably, the power transmission component is a busbar. In this embodiment, the subject of the present invention is therefore, - metal rod, - An intermediate layer made of inorganic materials, and - A coating layer made primarily from a composition comprising at least one polyamide having more than 6.5 carbon atoms per nitrogen atom, and at least one colorant. Includes, The intermediate layer is a busbar positioned between the metal rod and the coating layer.

[0032]

[0031] The power transmission components may be of any type. They are mainly high-voltage power transmission components. These components may be in the form of metal cables, or include metal fibers, for example, in the form of braids, or thin, overlapping metal sheets or metal rods, as is commonly used in busbars.

[0033]

[0032] Preferably, the power transmission components are cover parts for electrical or electronic components, control devices, connectors, battery relays, electrical cases, electrical terminals, or cables.

[0034]

[0033] Preferably, the power transmission component includes a metal surface made of copper, copper alloy, aluminum or aluminum alloy, preferably copper or aluminum, preferably copper.

[0035]

[0034] In one embodiment, the power transmission component is a busbar including a metal rod, the metal rod is preferably made of copper, a copper alloy, aluminum or an aluminum alloy, preferably copper or aluminum, preferably copper.

[0036] Interlayer made of inorganic materials

[0035] The intermediate layer is a layer of inorganic material. Preferably, this layer completely covers the metal rod.

[0037]

[0036] The inorganic material of the intermediate layer may be of any type, and is particularly selected from silicates, especially phyllosilicates, glass, carbon, more preferably mica, carbon fibers, glass fibers, and mixtures thereof. For example, the intermediate layer may be a mica layer, a glass fiber layer, or a carbon fiber layer, and is preferably a mica layer or a glass fiber layer.

[0038]

[0037] The intermediate layer is preferably in the form of an inorganic material ribbon, such as a mica ribbon, a carbon fiber ribbon, or a glass fiber ribbon, preferably a mica ribbon.

[0039]

[0038] The thickness of the inorganic material layer is preferably between 0.1 and 2 mm, preferably between 0.15 and 1 mm, and advantageously between 0.2 and 0.5 mm. Therefore, the thickness of the inorganic material ribbon is preferably between 0.1 and 2 mm, preferably between 0.15 and 1 mm, and advantageously between 0.2 and 0.5 mm.

[0040]

[0039] In the present invention, the term “intermediate layer made from inorganic material” means an intermediate layer that mainly, i.e., at least 50% by weight, preferably 50% to 99% by weight, for example 75% to 95% by weight, of the total weight, contains the inorganic material as defined above.

[0041]

[0040] The intermediate layer made from inorganic materials may also include, in addition to the inorganic materials described above, a binder resin (or matrix), which is a thermoplastic polymer resin or a thermosetting polymer resin, preferably a thermosetting polymer resin selected from epoxy resin, silicone, and polyurethane.

[0042]

[0041] A particularly advantageous feature is that the inorganic material layer maintains a stable color over a long period of time even at high temperatures, while also maintaining a certain degree of electrical insulation and mechanical strength even at very high temperatures.

[0043] coating layer

[0042] The power transmission component according to the present invention, preferably a busbar, includes a coating layer made from an electrically insulating composition mainly comprising at least one polyamide and at least one colorant, having a number of carbon atoms greater than 6.5 per nitrogen atom.

[0044]

[0043] In the present invention, the term "electrical insulation" refers to a material having a dielectric strength of more than 10 kV / mm, measured on a 1 mm thick plate on a sample that has been adjusted for 14 days at 25°C and 50% relative humidity, in accordance with the standard IEC 60243-1:2013.

[0045]

[0044] Preferably, the thickness of the coating layer is 0.1 mm to 2 mm, particularly 0.2 mm to 1 mm, particularly 0.3 mm to 0.8 mm, and more specifically 0.4 mm to 0.6 mm, while maintaining high flexibility to adapt to the strain of the power transmission components. If the material is too rigid, cracks and "waves" will occur, making it unsuitable for the application.

[0046] Composition of the coating layer

[0045] The composition forming the coating layer mainly comprises at least one polyamide having more than 6.5 carbon atoms per nitrogen atom, and at least one colorant.

[0047]

[0046] In the present invention, the term “primarily” means that the composition contains at least one polyamide in an amount greater than 50% by weight of the total weight of the composition. This or these polyamides constitute the matrix of the composition.

[0048]

[0047] Preferably, the coating layer composition contains at least one polyamide in an amount between 60% and 98% by weight, preferably between 70% and 95% by weight, relative to the total weight of the composition.

[0049]

[0048] Preferably, the coating layer composition contains a colorant in an amount between 0.5% and 10% by weight, preferably between 1% and 5% by weight.

[0050]

[0049] Preferably, the coating layer composition comprises a polyamide in an amount between 60% and 98% by weight, preferably between 70% and 95% by weight, and a colorant in an amount between 0.5% and 10% by weight, preferably between 1% and 5% by weight.

[0051]

[0050] In the case of PA-XY type homopolyamide [wherein X represents a unit obtained from a diamine and Y represents a unit obtained from a diacid], the number of carbon atoms per nitrogen atom is the average of the number of carbon atoms present in the unit derived from diamine X and the unit derived from diacid Y. Therefore, PA6.12 is a PA having 9 carbon atoms per nitrogen atom, i.e., C9 PA. PA6.13 is C 9.5 This is PA. For example, in the case of a copolyamide with structure XaYa / XbYb, the number of carbon atoms per nitrogen atom is calculated according to the same principle. The calculation is performed on a molar-proportional basis for various amide units, namely XaYa units and XbYb units.

[0052]

[0051] The main polyamide present in the coating layer composition has more than 6.5, preferably more than 8, carbon atoms per nitrogen atom.

[0053]

[0052] In the present invention, the term “mainly” means that the composition contains at least one polyamide in an amount exceeding 50% by weight of the total weight of the composition. In other words, the composition may contain a mixture of polyamides having more than 6.5 carbon atoms per nitrogen atom. This mixture must be main, i.e., it must account for at least 50% by weight of the total weight of the composition.

[0054]

[0053] Preferably, the composition contains at least one polyamide in an amount between 60% and 98% by weight, preferably between 70% and 95% by weight, relative to the total weight of the composition.

[0055]

[0054] In other words, the presence of other polyamides is not excluded. However, it is important that polyamides with a high number of carbon atoms are dominant in the composition.

[0056]

[0055] The polyamide present in the coating layer composition of the constituent elements according to the present invention is obtained by polycondensation of at least one unit selected from C6-C18 α,ω-aminocarboxylic acids, C5-C12 lactams, and (Ca diamine) (Cb diacid) units, where a represents the number of carbon atoms of the diamine and b represents the number of carbon atoms of the diacid, and a is between 4 and 36.

[0057]

[0056] Polyamides can be obtained by polycondensation of at least one lactam selected from pyrrolidinone, 2-piperidinone, enantractam, capryloractam, pelargolactam, decanolactam, undecanolactam, and lauryllactam.

[0058]

[0057] Polyamides can also be obtained by polycondensation of at least one amino acid selected from 9-aminononanoic acid, 10-aminodecanoic acid (indicated by 10), 11-aminoundecanoic acid (indicated by 11), and 12-aminododecanoic acid (indicated by 12).

[0059]

[0058] Polyamides can be obtained by polycondensation of at least one unit corresponding to the formula (Ca diamine)(Cb diacid), where a represents the number of carbon atoms in the diamine and b represents the number of carbon atoms in the diacid, and a and b are between 4 and 36.

[0060]

[0059] The (Ca diamine) unit may be aliphatic, alicyclic, or aromatic. The unit may be selected 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 as MXD), methylpentamethylenediamine (denoted as MPMD), bis(aminomethyl)cyclohexane (denoted as BAC), meta-xylylenediamine (MXD, CAS number 1477-55-0), and para-xylylenediamine (PXD, CAS number 539-48-0).

[0061]

[0060] Advantageously, the at least one C6-C12 diamine X is selected in particular from 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonameethylenediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine, and 1,12-dodecamethylenediamine.

[0062]

[0061] Advantageously, the diamine X used is a C10-C12 diamine, and is particularly selected from 1,10-decamethylenediamine, 1,11-undecamethylenediamine, and 1,12-dodecamethylenediamine.

[0063]

[0062] The (Cb diacid) unit may be aliphatic, alicyclic, or aromatic. The unit may be selected from succinic acid (b=4), pentanediic acid (b=5), adipic acid (b=6), heptanediic acid (b=7), octanedioic acid (b=8), azelaic acid (b=9), sebacic acid (b=10), undecanediic acid (b=11), dodecanediic acid (b=12), brassic acid (b=13), tetradecanediic acid (b=14), hexadecanedioic acid (b=16), octadecanediic acid (b=18), and diacids obtained from fatty acids, terephthalic acid (denoted as T).

[0064]

[0063] Advantageously, the (Cb diacid) unit is selected from adipic acid, suberic acid, azelaic acid, sebacic acid, undecanediic acid, dodecanediic acid, brassic acid, tetradecanediic acid, pentadecanediic acid, hexadecanedioic acid, and octadecanediic acid.

[0065]

[0064] Advantageously, the polyamide present in the composition according to the present invention has an elongation at break of >50%, preferably more than 100%, and more preferably more than 200%. The elongation at break can be measured in particular in accordance with the standard ISO 527-1 / -2.

[0066]

[0065] Advantageously, the composition according to the present invention contains less than 25% by weight, preferably less than 10% by weight, preferably less than 5% by weight, and preferably less than 1% by weight of polyamide having an elongation at break of 50% or less, based on the total weight of the composition. Preferably, the composition according to the present invention does not contain polyamide having an elongation at break of 50% or less.

[0067]

[0066] Advantageously, the polyamide present in the composition of the coating layer of the constituent element according to the present invention is an aliphatic or alicyclic polyamide. Preferably, the polyamide present in the composition of the coating layer of the constituent element according to the present invention is an aliphatic polyamide.

[0068]

[0067] Advantageously, the polyamide is selected from PA11, PA12, PA1010, PA1012, PA610, PA612, PA613, PA912, PA516, PA6 / 11, PA6 / 12, PA11 / 12, PA6 / 11 / 12, PA6 / 66 / 12, PA6 / 1010, PA6 / 1012, PA6 / 1010 / 1012, PA6 / 1012 / 12, PA6 / 66 / 11 / 12, and PA6 / 1010 / 1012 / 1014, either individually or in mixtures.

[0069]

[0068] Preferably, the composition comprises only polyamides having more than 6.5 carbon atoms per nitrogen atom. More specifically, the composition comprises only polyamides having more than 8 carbon atoms per nitrogen atom.

[0070]

[0069] According to a preferred embodiment, the polyamide is a homopolyamide. This homopolyamide can be obtained by polycondensation of lactam, amino acid, or (Ca diamine)(Cb diacid) units, where Ca and Cb are as defined above.

[0071]

[0070] More specifically, the composition mainly comprises PA11, PA12, PA1010, or PA1012, more preferably PA11 or PA12, and more preferably PA11.

[0072]

[0071] PA11 has the advantage of being manufactured from plant-derived raw materials. Plant materials can be cultivated in large quantities in most parts of the world according to demand and are bio-based. Bio-based raw materials are natural, animal, or plant resources that can be reconstituted in a short period of time on a human timescale. In particular, these raw materials need to be made as new as they are consumed.

[0073]

[0072] The basic raw material for PA11 is castor oil, which is castor oil extracted from the seeds of the plant of the same name (castor plant). PA11 is obtained by polycondensation of 11-aminoundecanoic acid.

[0074] Total acidity and total basicity

[0073] Preferably, the polyamide present in the coating layer composition of the constituent elements according to the present invention has a difference between the total acidity and total basicity of the polyamide, expressed as an absolute value, which is strictly less than 70, preferably less than 50, and ideally less than 30.

[0075]

[0074] In the present invention, the term difference expressed as an absolute value is understood to mean the result of subtracting the total acidity value of the polyamide from the total basicity value of the polyamide, without considering the sign.

[0076]

[0075] If the composition contains a mixture of polyamides, the acidity and basicity are measured for the polyamide mixture. Therefore, the difference is expressed relative to the polyamide mixture.

[0077]

[0076] Preferably, the polyamide present in the composition of the constituents according to the present invention also has a total basicity of less than 60 μequivalents / g, preferably less than 50 μequivalents / g, and ideally less than 40 μequivalents / g.

[0078]

[0077] Preferably, the polyamide present in the composition of the constituents according to the present invention also has a total acidity of less than 60 μequivalents / g, preferably less than 50 μequivalents / g, and ideally less than 40 μequivalents / g.

[0079]

[0078] Acidity and basicity are measured by potentiometric measurement.

[0080]

[0079] Acidity is measured according to the following method. The polyamide sample is dissolved in benzyl alcohol. Next, this sample is analyzed by potentiometric assay using a 0.02 N tetrabutylammonium hydroxide solution.

[0081]

[0080] The basicity is measured according to the following method. The polyamide sample is dissolved in metacresol. Next, this sample is analyzed by potentiometric measurement with a 0.02 N perchloric acid solution.

[0082]

[0081] According to one embodiment of the present invention, the polyamide has a total basicity of strictly less than 60 μequivalents / g and a total acidity of strictly less than 60 μequivalents / g, and the difference between the total acidity and the total basicity is expressed as an absolute value and is strictly less than 50, ideally less than 30.

[0083]

[0082] According to a preferred embodiment, the composition mainly comprises PA11, PA12, PA1010 or PA1012 and mixtures thereof, wherein the total basicity of this or these polyamides is less than 60 μequivalents / g, and the difference between its total acidity and total basicity is expressed as an absolute value, strictly less than 50, and ideally less than 30.

[0084]

[0083] According to a preferred embodiment, the composition mainly comprises PA11 or PA12, has a total basicity of less than 50 μequivalents / g, a total acidity of less than 60 μequivalents / g, and the difference between the total acidity and the total basicity is expressed as an absolute value and is strictly less than 30.

[0085]

[0084] Preferably, the polyamide present in the composition does not contain a chain limiting agent.

[0086] intrinsic viscosity

[0085] Preferably, the polyamide in the coating layer composition has an intrinsic viscosity greater than 1.1, preferably greater than 1.2, as measured in accordance with the standard ISO 307:2007.

[0087]

[0086] The measurement was performed at 20°C on a 75 mg sample with a concentration of 0.5% (m / m) in m-cresol.

[0088]

[0087] If the composition contains a mixture of polyamides, the viscosity is measured with respect to the polyamide mixture.

[0089] Enthalpy of melting

[0088] Preferably, the polyamide in the coating layer composition has a melting enthalpy of more than 20 J / g, preferably more than 30 J / g, and ideally more than 40 J / g.

[0090]

[0089] The enthalpy of fusion is measured by DSC (differential scanning calorimetry) in accordance with the standard ISO 11357-3, 2013 (second DSC heating at 20°C / min in accordance with the standard ISO 11357).

[0091]

[0090] If the composition contains a mixture of polyamides, the enthalpy of fusion is measured for the polyamide mixture.

[0092] crystallization temperature

[0091] Preferably, the polyamide in the coating layer composition has a crystallization temperature of less than 180°C, preferably less than 160°C.

[0093]

[0092] The crystallization temperature is measured by DSC (Differential Scanning Calorimetry) in accordance with the standard ISO 11357-3, 2013 (second DSC heating at 20°C / min in accordance with the standard ISO 11357).

[0094]

[0093] If the composition contains a mixture of polyamides, the crystallization temperature is measured for the polyamide mixture.

[0095] coloring agent

[0094] The coating layer composition of the constituent elements according to the present invention comprises at least one colorant. The colorant may be a dye or a pigment, in other words, a water-soluble dye or a water-insoluble pigment, depending on the conditions defined below.

[0096]

[0095] The colorant may be any type known to those skilled in the art. Preferably, the colorant according to the present invention is selected from the group consisting of azo dyes, anthraquinone dyes, indigo dyes, triarylmethane dyes, chlorine dyes and polymethine dyes.

[0097]

[0096] The term "pigment" refers to any pigment that gives color to a polymer composition. Their solubility in water at 25°C and atmospheric pressure (760 mmHg) is less than 0.05% by weight, preferably less than 0.01%. Usable pigments are selected from organic and / or mineral pigments known in the art, in particular those described in Kirk-Othmer's "Encyclopedia of Chemical Technology" and Ullmann's "Encyclopedia of Industrial Chemistry".

[0098]

[0097] The pigments may be of natural or non-natural origin. These pigments may be in the form of pigment powder or paste. They may be coated or not. The pigments can be selected from, for example, mineral pigments, organic pigments, and mixtures thereof.

[0099]

[0098] The term "mineral pigment" refers to a pigment that meets the definition in the chapter on inorganic pigments in Ullmann's Encyclopedia. Mineral pigments useful in the present invention include loess elements such as red loess [clay (especially kaolinite) and iron hydroxide (e.g., hematite)], brown loess [clay (especially kaolinite) and limonite], yellow loess [clay (especially kaolinite) and goethite], optionally surface-treated titanium dioxide, zirconium oxide or cerium oxide, zinc oxide, iron oxide (black, yellow or red) or chromium oxide, manganese violet, ultramarine, chromium hydrate and iron blue, and metal powders, such as aluminum powder or copper powder.

[0100]

[0099] Other examples include alkaline earth metal (such as calcium or magnesium) carbonates, silicon dioxide, quartz, and other compounds used as inert fillers in cosmetic compositions, which give the composition color or whiteness under the conditions of use.

[0101]

[0100] Preferably, the composition of the present invention does not contain the aforementioned metal salts, aluminum salts, or copper salts.

[0102]

[0101] The pigment may be an organic pigment. The term "organic pigment" means a pigment that corresponds to the definition in the chapter "Organic Pigments" in Ullmann's Encyclopedia.

[0103]

[0102] Organic pigments can be selected in particular from nitroso, nitro, azo, xanthene, pyrene, quinolein, quinoline, anthraquinone, triphenylmethane, fluorane, phthalocyanine, metal complexes, isoindolinone, isoindoline, quinacridone, perinone, perylene, diketopyrrolopyrrole, indigo, thioindigo, dioxazine, triphenylmethane, and quinophthalone compounds.

[0104]

[0103] In particular, white or colored organic pigments include carmine, carbon black, aniline black, azo yellow, quinacridone, phthalocyanine blue, blue pigments coded in the Color Index with reference numbers CI 42090, 69800, 69825, 74100, 74160, yellow pigments coded in the Color Index with reference numbers CI 11680, 11710, 19140, 20040, 21100, 21108, 47000, 47005, green pigments coded in the Color Index with reference numbers CI 61565, 61570, 74260, orange pigments specified in the Color Index with reference numbers CI 11725, 45370, 71105, and other pigments with reference numbers CI You can choose from the red pigments specified in 12085, 12120, 12370, 12420, 12490, 14700, 15525, 15580, 15620, 15630, 15800, 15850, 15865, 15880, 26100, 45380, 45410, 58000, 73360, 73915, and 75470.

[0105]

[0104] Advantageously, the pigments are selected from CI Pigment Orange 82 [CAS No. 2170864-77-2] and CI Pigment Yellow 216 [CAS No. 817181-98-9]. Pigment Orange 82 is available, for example, from Sun Chemical GmbH in Ludwigshafen, Germany, under the name Sicopal® Orange K2430. Pigment Yellow 216 is available, for example, from Shepherd in Ghent, Belgium, under the name Orange 10P340.

[0106]

[0105] Carminic acid is an example of a coloring agent. Other coloring agents known by the following names are also mentioned. 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 5(CI 61 570), D&C Yellow 10(CI 77 002), D&C Green 3(CI 42 053), D&C Blue 1(CI 42 090).

[0107]

[0106] The colorants can be selected from the group consisting of titanium dioxide, carbon black, cobalt oxide, nickel titanate, molybdenum disulfide, aluminum flakes, iron oxide, zinc oxide, phthalocyanine and anthraquinone derivatives, and zinc phosphate.

[0108]

[0107] According to any one embodiment, the composition according to the present invention contains less than 1% by weight, particularly less than 0.1% by weight, of a carbon-based filler based on the total weight of the composition.

[0109]

[0108] In the present invention, the term "carbon-based filler" means a granular object that contains only carbon atoms in its mass, "excluding impurities," and that other atoms may be present on the surface. Carbon-based fillers can be selected from, but are not exhaustive, carbon black, natural and synthetic graphite, carbon fibers, graphene, fullerene, acetylene black, and carbon nanotubes.

[0110]

[0109] According to any one embodiment, the composition according to the present invention contains less than 0.1% by weight of carbon black based on its total weight. Preferably, the composition according to the present invention does not contain carbon black.

[0111]

[0110] Preferably, the composition according to the present invention comprises at least one colorant that gives a color other than black.

[0112]

[0111] Preferably, the composition according to the present invention contains less than 1% by weight, particularly less than 0.1% by weight, preferably 0% by weight, of a colorant having an L* parameter of less than 10, particularly less than 5, particularly less than 1, particularly equal to 0, the L* parameter being measured in the CIELab system as defined in ISO 11664-4:2008, using a Konica Minolta CM-36dGV spectrophotometer in reflectance mode under conditions including a light source D65, an incident angle of 10°, an aperture of 8mm, and a specular reflection component.

[0113]

[0112] Preferably, the selected colorants(s) result in a composition having the following:

[0113] - L* parameter between 10 and 100, preferably between 20 and 80, advantageously between 40 and 75, particularly between 50 and 70, and / or

[0114] - a* parameter between 10 and 100, preferably between 20 and 80, advantageously between 35 and 55, and / or

[0115] - an ab* parameter between 10 and 100, preferably between 20 and 80, advantageously between 40 and 75, and particularly between 50 and 70. Here, the L*, a*, and b* parameters were measured using a Konica Minolta CM-36dGV spectrophotometer under the conditions defined in ISO 11664-4:2008, with a light source D65, an incident angle of 10°, an aperture of 8mm, and including a specular component, in a CIELab system.

[0114]

[0116] Preferably, the coating layer composition includes at least one colorant that gives it an orange color.

[0115]

[0117] Preferably, the selected colorant results in a RAL 2003 color composition, i.e., the composition having the following L*a*b* values: L*=66.0, a*=41.2, and b*=52.4.

[0116]

[0118] Advantageously, the colorant is a mixture of at least two pigments. More preferably, the colorant comprises titanium dioxide, tin oxide, zinc oxide, and mixtures thereof. Even more preferably, the colorant comprises titanium dioxide, tin oxide, zinc oxide, and at least two additional pigments, and is preferably orange in color.

[0117]

[0119] Preferably, the colorant content in the composition is between 0.5% and 10% by weight, and more favorably between 1% and 5% by weight, relative to the total weight of the composition.

[0118]

[0120] Preferably, the content of black colorants, particularly black pigments, carbon black, or other black fillers, is limited to a maximum of 0.1% by weight.

[0119]

[0121] Preferably, black colorants are excluded.

[0120]

[0122] Preferably, the color of the composition is characterized in that the color measured by the RAL method is other than RAL color 2100, 6015, 7021, 8022, 9004, 9005, 9011, 9017, or 9021.

[0121]

[0123] Preferably, the coating layer composition comprises a polyamide in an amount between 60% and 98% by weight, preferably between 70% and 95% by weight, and a colorant in an amount between 0.5% and 10% by weight, preferably between 1% and 5% by weight.

[0122] additives

[0124] Preferably, the composition according to the present invention comprises at least one additive selected from flame retardants, ultraviolet protective agents, ultraviolet stabilizers, heat stabilizers, lubricants, fluidity enhancers, injectability enhancers, film-forming agents, fillers, film-forming aids, gums, preservatives, antimicrobial agents, and mixtures thereof. Preferably, the composition according to the present invention contains no metal-based additives at all in order to avoid harmful interactions between the metal surface to be coated and these additives potentially present in the composition according to the present invention.

[0123] Antioxidant

[0125] Preferably, the coating layer composition contains at least one antioxidant.

[0124]

[0126] For example, stabilizers may be combinations of organic stabilizers, or more generally, phenolic antioxidants (e.g., Ciba-BASF's Irganox® 245, 1098, or 1010), or phosphite antioxidants (e.g., Ciba-BASF's Irgafos® 126 or Irgafos® 168). Optionally, other stabilizers such as hindered amine light stabilizers (e.g., Ciba-BASF's Tinuvin® 770), UV inhibitors (e.g., Ciba-BASF's Tinuvin® 312), or phosphorus-based stabilizers may also be used. Additionally, amine antioxidants such as Crompton's Naugard® 445, or polyfunctional stabilizers such as Clariant's Nylostab® S-EED may also be used.

[0125]

[0127] According to a preferred embodiment, the power transmission component includes a metal surface, and the metal surface has a surface across its entire surface. - An intermediate layer made of inorganic materials, and - A coating layer made from a composition mainly comprising at least one polyamide and at least one colorant, having more than 8 carbon atoms per nitrogen atom. It is coated with The intermediate layer is positioned between the metal surface of the power transmission component and the coating layer. The metal surface is characterized by being made of copper.

[0126]

[0128] In a more preferred embodiment, the power transmission component includes a metal surface, and the metal surface has a surface across its entire surface, - An intermediate layer made of inorganic materials, and - A coating layer made from a composition, - Primarily consisting of at least one polyamide, - The difference between total acidity and total basicity, expressed as an absolute value, less than 70. - Total basicity less than 60 μequivalents / g A coating layer made from a composition mainly comprising at least one polyamide, having the following characteristics: It is coated with The composition mainly comprises at least one polyamide having more than 6.5 carbon atoms per nitrogen atom, and at least one colorant. The intermediate layer is positioned between the metal surface of the power transmission component and the coating layer. The metal surface is characterized by being made of copper.

[0127] Use of power transmission components

[0129] In one embodiment, the power transmission component, preferably the busbar, is located inside and / or outside a battery, particularly a vehicle battery, especially an automobile battery. For example, the component may be immersed in a coolant.

[0128] Method for preparing power transmission components

[0130] In yet another aspect, the present invention relates in particular to a method for preparing power transmission components for a battery, preferably busbars, - A process of coating the entire metal surface of the power transmission component with the above-mentioned inorganic intermediate layer, and the subsequent steps - A step of coating an intermediate layer of inorganic material with the coating composition defined above. Regarding methods including

[0129]

[0131] In yet another aspect, the present invention relates in particular to a method for preparing busbars for a battery, - The process of coating the entire metal surface of the busbar with the intermediate layer of the inorganic material mentioned above, and the subsequent steps - A step of coating an intermediate layer of inorganic material with the coating composition defined above. Regarding methods including

[0130]

[0132] Preferably, the step of covering an intermediate layer of an inorganic material with the coating composition defined above can be carried out by extruding the composition, or by depositing the powder of the coating composition and then melting the powder.

[0131]

[0133] Preferably, the preparation method includes an extrusion step but does not include a powder coating step.

[0132]

[0134] The metal surface of the power transmission component, preferably a metal rod, can be subjected to a pretreatment step before being covered with an intermediate layer of inorganic material. This method may include, for example, a step of degreasing the metal surface and / or a flame treatment step and / or a preheating step.

[0133]

[0135] All the characteristics defined above are effective for this method.

[0134]

[0136] Other objects and advantages of the present invention will become apparent from the following examples, which do not imply any limitations.

[0135] Examples Preparation of coating composition

[0137] The coating composition according to the present invention was prepared using the following compounds.

[0136]

[0138] PA11, designated as a polyamide, is prepared according to the following method: 43.00 kg of 11-aminoundecanoic acid, 30 g of phosphoric acid, and 6.0 kg of deionized water are placed in an autoclave and heated at 250°C for 30 minutes while maintaining the autosynthesis pressure. Once the monomers have melted, the mixture is stirred at 40 rpm throughout the synthesis. The mixture is gradually expanded over 2 hours, the pressure is reduced to 1 bar, and the temperature is raised to 255°C. Then, while maintaining the temperature at 255°C, nitrogen is introduced into the system at a flow rate of 100 L / hour for 30 minutes. Finally, stirring is stopped and the molten mass is extruded at a pressure of 6 bar. The lot is cooled in a water bath and then granulated.

[0137]

[0139] Polyamide PA12 is prepared by the following method: 25.00 kg of laurolactam and 2.20 kg of deionized water are placed in an autoclave and heated at 290°C for 5 hours under a pressure of 32 bar. Once the monomers have melted, the mixture is stirred at 40 rpm throughout the synthesis. The mixture is gradually expanded over 8 hours while maintaining the temperature at 290°C, and the pressure is reduced to 8 bar. Subsequently, the mixture is gradually expanded over 1 hour to 0.2 bar while maintaining the temperature at 265°C. Then, nitrogen is introduced into the system at a flow rate of 100 L / hour for 15 minutes while maintaining the temperature at 265°C. Finally, the system is evacuated and the pressure is maintained at 0.3 bar for 15 minutes. Finally, stirring is stopped and the molten mass is pushed out under a pressure of 10 bar. The lot is cooled in a water bath and then granulated.

[0138]

[0140] The polyamides tested have the characteristics shown in Table 1 below. TIFF2026531710000001.tif96170Table 1

[0139] Measurement of total basicity

[0141] Basicity is measured according to the following method: 1 g of polyamide is dissolved in 80 ml of hot metacresol. The sample is then cooled. Next, it is analyzed by potentiometric measurement with a 0.02 N solution of perchloric acid in acetic acid using a Metrohm titrator (888 or 716) combined with a pH electrode. The graph of the potential as a function of volume gives a jump due to the equivalent volume, from which the total basicity is calculated using the following formula. TIFF2026531710000002.tif12170 formula, Veq represents the equivalent volume obtained by potentiometer titration. [HClO4] represents the concentration of the perchloric acid solution, i.e., 0.02N. m represents the mass of the sample, i.e., 1g.

[0140] Measurement of total acidity

[0142] 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. Next, it is analyzed by potentiometric measurement with a 0.02 N tetrabutylammonium hydroxide solution using a Metrohm titrator (888 or 716) and a combined pH electrode. The graph of the potential as a function of volume gives a jump due to the equivalent volume, from which the total acidity is calculated using the following formula. TIFF2026531710000003.tif12170 formula, Veq represents the equivalent volume obtained by potentiometer titration. [TBAOH] represents the concentration of tetrabutylammonium hydroxide solution, i.e., 0.02N. m represents the mass of the sample, i.e., 1g.

[0141] Calculation of the difference between total acidity and total basicity

[0143] The difference is obtained as an absolute value, i.e., without considering the sign, by calculating the subtraction between the values ​​of total acidity and total basicity.

[0142]

[0144] For example, regarding PA11: TIFF2026531710000004.tif7170

[0143] Measurement of intrinsic viscosity

[0145] Measurements were performed at 20°C on a 75 mg sample with a concentration of 0.5% (m / m) in m-cresol. The intrinsic viscosity is calculated according to the following formula. Intrinsic viscosity=ln(t s / t0) × 1 / C, C = m / p × 100 During the ceremony, t s t0 is the flow time of the solution, m is the flow time of the solvent, m is the mass of the sample whose viscosity is being measured, and p is the mass of the solvent. This measurement conforms to the ISO 307:2007 standard, except that the measurement temperature is 20°C instead of 25°C.

[0144] Measurement of enthalpy of melting

[0146] The enthalpy of fusion is measured during the second heating by DSC in accordance with standard ISO 11357-3:2013.

[0145] Measurement of crystallization temperature

[0147] The crystallization temperature is measured in accordance with the standard ISO 11357-3:2013, using differential scanning calorimetry (DSC) while cooling at a rate of 20°C / min.

[0146]

[0148] The tested compositions also include the following compounds:

[0149] A phenolic primary antioxidant (CAS number 36443-68-2) sold by BASF under the trade name Irganox 245 (registered trademark).

[0147]

[0150] A secondary phosphite-based antioxidant (CAS number 31570-04-4) sold by BASF under the trade name Irgafos 168 (registered trademark).

[0148]

[0151] A pigment mixture sold by Avient under the trademark name 338160 ORA LLDPE AO Smartbatch, containing 28% pigment.

[0149]

[0152] The following compositions are manufactured by mixing various molten starting materials in a 26 mm diameter co-rotating twin-screw extruder. The product is extruded at a flow rate of 16 kg / hour, a temperature of 250°C, and a screw speed of 250 rpm. The product discharged from the machine is cooled by passing through a water tank and then granulated. These products are finally vacuum-dried at 80°C for 8 hours. The composition formulations are shown in Table 2 below, and the content is expressed as a weight percentage of the total weight of the composition. TIFF2026531710000005.tif59170Table 2

[0150] Sample preparation

[0153] From these compositions, plates (60 × 60 × 1 mm) and ISO 527-1A dumbbells are injection molded at a temperature of 260°C.

[0151] Measurement of mechanical properties

[0154] Tensile mechanical properties are measured for dry samples in accordance with the standard ISO 527-1:2012. The machine used is an Instron 5966 with a crosshead speed of 50 mm / min.

[0152]

[0155] Resistance to antifreeze salts is measured in accordance with EN16811-1:2016 using a 1 mm thick plate.

[0153]

[0156] The results are shown in Table 3 below. TIFF2026531710000006.tif17170Table 3

[0154] Measurement of optical and electrical properties:

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

[0155]

[0158] The color characteristics of the sample are measured using a Konica Minolta CM-36dGV spectrophotometer under the conditions defined in ISO 11664-4:2008, with a D65 light source, an incident angle of 10°, an aperture of 8mm, and including specular reflection components, in a CIELab system.

[0156]

[0159] In this L*a*b* system, L* represents lightness, a* represents the green / red color axis, and b* represents the blue / yellow color axis. The higher the L* value, the brighter and less intense the color. Conversely, the lower the L* value, the darker and more vivid the color. The higher the a* value, the redder the hue, and the higher the b* value, the yellower the hue. The results are shown in Table 4 below. TIFF2026531710000007.tif33170Table 4

[0157]

[0160] For each of compositions A and B, the dielectric strength remained above 10kV / mm after aging at 150°C for 240 hours in a ventilated oven.

[0158] Preparation of coated metal rods

[0161] A 60 × 60 × 1 mm plate is prepared by injection molding at 260°C from each of composition A and composition B.

[0159]

[0162] The following intermediate layers are used.

[0163] Intermediate layer 1: Woven fiberglass film sold by Yuniu Fiberglass Roving under the name YN-FW-001

[0160]

[0164] Intermediate layer 2: This is a mica film sold by Final Advanced Materials under the name MC-5000HT, made from approximately 90% phlogopite and 10% silicone binder resin.

[0161]

[0165] The structure representative of the present invention is prepared by stacking the following layers. Composition A or B / Intermediate layer 1 or 2 / Copper / Intermediate layer 1 or 2 / Composition A or B.

[0162]

[0166] This assembly is enclosed in a frame of the same thickness as the entire assembly and compressed in a press at 220°C. The press plate is in contact with the stacked layers for 90 seconds without applying pressure. Next, a pressure of 50 bar is applied for 60 seconds. Finally, the assembly is cooled for 2 minutes while maintaining a pressure of 30 bar. A comparative example is prepared similarly without an intermediate layer. The structures are shown in Table 5 below. TIFF2026531710000008.tif25170Table 5

[0163] Evaluation of the structure Evaluation of color changes

[0167] The multilayer structure is aged in a ventilated oven at 150°C for 240 hours.

[0164]

[0168] ΔE is measured on copper plates coated with the aged composition and on copper plates coated with the composition and an intermediate layer, which are also aged.

[0165]

[0169] Before and after this aging process, the color characteristics of the sample are measured using a Konica Minolta CM-36dGV spectrophotometer under the conditions defined in ISO 11664-4:2008, with a D65 light source, an incident angle of 10°, an aperture of 8mm, and including specular reflection components, in a CIELab system.

[0166]

[0170] In this L*a*b* system, L* represents lightness, a* represents the green / red color axis, and b* represents the blue / yellow color axis. The higher the L* value, the brighter and less intense the color. Conversely, the lower the L* value, the darker and more vivid the color. The higher the a* value, the redder the hue, and the higher the b* value, the yellower the hue. Therefore, color aging corresponds to the change in color between an unaged plate (i.e., t = 0) and a plate aged at 150°C for t = 240 hours. This change is measured by ΔE according to the following equation. TIFF2026531710000009.tif14170

[0167]

[0171] In this equation, L*, a*, and b* represent the measured values ​​of the aged plate at t=240 hours, while L0*, a0*, and b0* represent the measured values ​​of the unaged plate. A higher value of ΔE indicates a greater change in color due to aging and greater instability in the composition.

[0168]

[0172] The results are shown in Table 6 below. TIFF2026531710000010.tif26170Table 6

[0169] Evaluation of high temperature resistance:

[0173] The illustrated structure is placed in a furnace at 500°C for 5 minutes. Dielectric strength measurements are performed on these samples in accordance with IEC 60243-1:2013.

[0170]

[0174] The results of the evaluation test are shown in Table 7 below. TIFF2026531710000011.tif26170Table 7

[0171]

[0175] The examples demonstrate that the structure according to the present invention possesses good mechanical properties and exhibits color stability over time, while simultaneously retaining a certain degree of electrical insulation (see dielectric strength results) after being exposed to 500°C (and the burning of the polyamide layer). Therefore, the inorganic material layer has the advantage of maintaining insulation even after exposure to 500°C without guaranteeing a good level of dielectric strength (>10kV / mm).

[0172]

[0176] As mentioned above, the dielectric strengths of compositions A and B remained above 10 kV / mm after aging at 150°C for 240 hours in a ventilated oven.

Claims

1. A power transmission component comprising a metal surface, wherein the metal surface extends over its entire surface, - An intermediate layer made of inorganic materials, and - A coating layer having a color other than black, made primarily from an electrically insulating composition comprising at least one polyamide having more than 6.5 carbon atoms per nitrogen atom and at least one colorant. It is coated with A power transmission component characterized in that the intermediate layer is positioned between the metal surface of the power transmission component and the coating layer.

2. The composition according to claim 1, characterized in that the intermediate layer made of inorganic material is not a metal.

3. The composition according to claim 1 or 2, characterized in that the composition comprises 60% to 98% by weight of at least one polyamide.

4. The composition according to any one of claims 1 to 3, characterized in that the at least one polyamide is an aliphatic or alicyclic polyamide.

5. The power transmission component according to any one of claims 1 to 4, wherein the power transmission component is a busbar.

6. The power transmission component according to any one of claims 1 to 5, wherein the metal surface is made of copper, a copper alloy, aluminum, or an aluminum alloy.

7. The power transmission component according to any one of claims 1 to 6, wherein the intermediate layer made from an inorganic material is a layer of mica, carbon fiber, or glass fiber, preferably mica.

8. The power transmission component according to any one of claims 1 to 7, wherein the intermediate layer made of an inorganic material has a thickness between 0.1 mm and 2 mm, preferably between 0.15 mm and 1 mm.

9. The power transmission component according to any one of claims 1 to 8, characterized in that the coloring agent content is in the range of 0.5% to 10% by weight, preferably 1% to 5% by weight, based on the total weight of the composition.

10. The power transmission component according to any one of claims 1 to 9, characterized in that the polyamide of the coating layer has an intrinsic viscosity greater than 1.1, as measured in accordance with the standard ISO 307:2007.

11. The power transmission component according to any one of claims 1 to 10, characterized in that the polyamide of the coating layer has a melting enthalpy of exactly more than 20 J / g, as measured in accordance with DSC during a second heating in accordance with the standard ISO 11357-3, 2013.

12. The power transmission component according to any one of claims 1 to 11, characterized in that the polyamide of the coating layer has a crystallization temperature of strictly less than 180°C, as measured by DSC during the second heating in accordance with the standard ISO 11357-3, 2013.

13. The power transmission component according to any one of claims 1 to 12, characterized in that the polyamide of the coating layer is selected from PA11, PA12, PA1010, PA1012, PA610, PA612, PA613, PA516, PA912, PA6 / 11, PA6 / 12, PA11 / 12, PA6 / 11 / 12, PA6 / 66 / 12, PA6 / 1010, PA6 / 1012, PA6 / 1010 / 1012, PA6 / 1012 / 12, PA6 / 66 / 11 / 12 and PA6 / 1010 / 1012 / 1014 individually or as a mixture thereof, more specifically from PA11, PA12, PA1010 or PA1012, even more preferably from PA11 or PA12, preferably from PA11.

14. The power transmission component according to any one of claims 1 to 13, characterized in that the polyamide of the coating layer composition has a difference between its total acidity and total basicity of less than 70, expressed as an absolute value, and a total basicity of the polyamide of less than 60 μequivalents / g, and the total acidity and total basicity are measured by potentiometric measurement.

15. The power transmission component according to any one of claims 1 to 14, characterized in that the polyamide of the coating composition has a total acidity of less than 60 μequivalents / g as measured by potentiometric measurement.

16. A method for preparing a power transmission component according to any one of claims 1 to 15, - A step of coating the entire metal surface of a power transmission component with an intermediate layer of inorganic material according to any one of claims 1, 7, and 8, and thereafter - A step of coating an intermediate layer of an inorganic material with the coating composition according to any one of claims 1 and 9 to 15. A method that includes this.

17. The method according to claim 16, characterized in that the process of coating the intermediate layer is carried out by extrusion.

18. The method according to claim 16, characterized in that the step of coating an intermediate layer is performed by depositing the powder of the coating composition and then melting the powder.

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