Colored polyamide composition for covering electrical transmission member

Abstract

The present invention relates to an electrically insulating composition for covering an electrical transmission component, the composition comprising:-predominantly at least one polyamide having:-the total acidity of the polyamide or the difference between the total alkalinity of the polyamide or the polyamide, expressed in absolute value, is less than 70,-the total acidity of the polyamide or the difference between the total alkalinity of the polyamide or the polyamide, expressed in absolute value, and-the total alkalinity of the polyamide or the polyamide, expressed in absolute value, is less than 70; the total alkalinity and the total acidity are measured by potentiometry; and-a total alkalinity of less than 60 [mu] eq / g measured by potentiometry, and mainly comprising at least one polyamide having a carbon number of greater than 6.5 per nitrogen atom and-at least one colorant, characterized in that the colour of the composition is different from black, and the use thereof for covering electrical transmission parts, in particular for covering electrical transmission parts, in particular for covering electrical transmission parts. A battery interconnection strip is preferably selected.

Description

Technical Field

[0001] The present invention relates to coloring compositions for covering power transmission components, particularly battery busbars. Background Technology

[0002] In the field of electric vehicles, there are connectors known as busbars (interconnects) used to circulate high-intensity current both inside and outside the battery. These bars must be covered with an insulating coating that is resistant to mechanical stress and aging.

[0003] There are many methods for producing busbars. One major one is to extrude a polymer composition around a central metal strip. Powder coating, dip coating, or electro-spraying methods can also be used. These structures are then cut and bent (at ambient temperature) to achieve the shape required for the vehicle layout.

[0004] For safety reasons, these strips must also have a unique color representing the current flowing through them. Therefore, this color must remain stable over time, regardless of the temperature the strip may be exposed to. In fact, external conditions, proximity to the engine, self-heating from the flow of current, and especially during battery charging, are factors that can affect the coating color over time. If the color changes over time, questions may arise about the voltage of the current flowing through the strip, potentially leading to accidents, for example, during engine maintenance or repair. Therefore, color stability is essential despite the harsh environmental conditions.

[0005] A technical challenge associated with battery busbar applications is forming a thin polymer layer whose color does not change over time, while maintaining a high level of flexibility to accommodate busbar deformation. During bending, excessively rigid material forms cracks on the outer surface and buckles on the inner surface, which is considered "ripples" or "beads," an unacceptable phenomenon for the application.

[0006] Therefore, the material's behavior at its yield point is crucial. Low stress and high elongation at yield are desirable. These coatings maintain low stress levels, but nevertheless, the material must have an elongation at break >50%, preferably >100%, and even more advantageously >200%. Good abrasion resistance is also necessary for this application.

[0007] Furthermore, depending on the location of these parts within the engine, these compositions may be advantageous in their resistance to de-icing salt.

[0008] The coating must also act as an electrical insulator, meaning it must maintain properties such as breakdown voltage, dielectric strength, and relative tracking index (CTI) >600 V. This insulation must be maintained during accelerated thermal aging, which can reach up to 130°C, and notably up to 150°C.

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

[0010] Furthermore, existing technologies do not provide information on combining these elements in a formulation to simultaneously achieve the flexibility and color stability required for battery busbar applications.

[0011] US 2021 / 0253854 and KR101977321 disclose compositions based on polyamide and at least one pigment system. However, from a mechanical point of view, the disclosed compositions are found to be unsatisfactory. Furthermore, color changes in these products during aging are not documented. Summary of the Invention

[0012] This invention relates to an electrical insulating composition for covering power transmission components, comprising:

[0013] - Primarily at least one polyamide, the polyamide having:

[0014] - The absolute value difference between the total acidity and the total basicity of the polyamide, which is less than 70.

[0015] - Total alkalinity less than 60 μeq / g, and

[0016] - Primarily at least one polyamide having a carbon number greater than 6.5 per nitrogen atom, and

[0017] - At least one colorant.

[0018] Preferably, the electrically insulating composition is characterized in that its color is different from black.

[0019] According to one embodiment, the electrical insulating composition may have an L value greater than 0, preferably greater than 5, preferably greater than 10. The parameters, measured in the CIELab system as defined in standard ISO 11664-4:2008, were measured in reflectance mode using a Konica Minolta CM-36dGV spectrophotometer with a D65 light source, an incident angle of 10°, an aperture of 8 mm, and including the specular component.

[0020] According to one embodiment, the electrical insulating composition may have a color determined according to the RAL method, which is different from RAL colors 2100, 6015, 7021, 8022, 9004, 9005, 9011, 9017 and 9021.

[0021] Preferably, the coating composition comprises 60% to 98% by weight of the at least one polyamide.

[0022] Preferably, the coating composition is characterized in that the at least one polyamide is an aliphatic or alicyclic polyamide, preferably an aliphatic polyamide.

[0023] The present invention also relates to its use in covering power transmission components.

[0024] The present invention also relates to a power transmission component comprising:

[0025] - Power transmission components with metallic surfaces, and

[0026] - A coating made from the composition as defined above.

[0027] Finally, the present invention relates to a method for manufacturing power transmission components.

[0028] It has been observed that the color of the composition according to the invention remains stable even after aging at high temperatures. It has also been observed that the composition continues to possess certain electrical insulation properties after aging. Furthermore, the composition according to the invention exhibits excellent mechanical properties: the elongation at break, impact strength, and the performance of the polymer layer during metal strip bending are very satisfactory. The composition also exhibits good chemical resistance, i.e., good resistance to de-icing salts. Finally, electrical components coated with the composition remain easily peelable.

[0029] Other advantageous features of the method according to the invention are as follows:

[0030] - The polyamide has an intrinsic viscosity greater than 1.1 as measured according to standard ISO 307:2007;

[0031] - The polyamide has a melting enthalpy greater than 20 J / g as measured by DSC during the second heating run according to standard ISO 11357-3:2013;

[0032] - The polyamide has a crystallization temperature strictly below 180°C as measured by DSC during the second heating operation according to standard ISO 11357-3:2013;

[0033] -The polyamide has a total acidity of less than 60 μeq / g;

[0034] - The polyamide is selected from PA 11, PA 12, PA 1010, PA 1012, PA 610, PA 612, PA 516, PA 613, PA 912, PA 516, PA 6 / 11, PA 6 / 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, more particularly PA 11, PA 12, PA 1010, PA 1012, even more preferably PA 11 or PA 12, preferably PA 11.

[0035] - A colorant is a mixture of at least two pigments;

[0036] - Colorants include titanium dioxide, tin oxide, zinc oxide, and mixtures thereof;

[0037] - The colorant contains titanium dioxide, tin oxide, zinc oxide, and orange pigment;

[0038] - The colorant content ranges from 0.5% to 10% by weight, preferably from 1% to 5% by weight, relative to the total weight of the composition;

[0039] -The composition contains at least one antioxidant;

[0040] - The metal surfaces of power transmission components are made of copper, copper alloys, aluminum, or aluminum alloys;

[0041] -The component is a busbar;

[0042] - A method for preparing power transmission components includes a step of pretreating the metal surface by degreasing and / or flame treatment and / or preheating steps. Detailed Implementation

[0043] Other features, aspects, subjects, and advantages of the invention will become clearer from the following description.

[0044] The nomenclature used to define polyamides is described in standard ISO 1874-1:2011 “Plastics—Polyamide (PA) Moulding and Extrusion Materials—Part 1: Designation,” particularly on page 3 (Tables 1 and 2), and is well known to those skilled in the art. Therefore, PA 11 refers to polyamide obtained by the polycondensation of 11-aminoundecanoic acid. PA 12 is obtained by the polycondensation of laurolactam. PA 1010 is obtained by the polycondensation of decanediamine (10) and sebacic acid (10). PA 1012 is obtained by the polycondensation of decanediamine (10) and dodecanoic acid (12).

[0045] Furthermore, it is stipulated that the expression “between… and…” and the phrase “(from)… to (to)…” used in this specification shall be understood to include each endpoint mentioned.

[0046] The term "polyamide" encompasses both homopolymers and copolymers.

[0047] The invention will now be described in more detail in a non-limiting manner in the following description.

[0048] Composition

[0049] The composition according to the invention is an electrical insulating composition for covering power transmission components, comprising:

[0050] - Primarily at least one polyamide, the polyamide having:

[0051] - The absolute value difference between the total acidity and the total basicity of the polyamide, which is less than 70.

[0052] - Total alkalinity less than 60 μeq / g, and

[0053] - Primarily at least one polyamide having a carbon number greater than 6.5 per nitrogen atom, and

[0054] - At least one colorant.

[0055] Preferably, the electrically insulating composition is characterized in that its color, as determined by the RAL method, is different from black. The term "black" is intended to refer 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.

[0056] For the purposes of this invention, the term "electrical insulation" refers to a material with a dielectric strength greater than 10 kV / mm, measured on a 1 mm thick plate according to standard IEC 60243-1:2013 for a sample conditioned for 14 days at 25°C and 50% relative humidity.

[0057] The composition mainly contains at least one, namely one or more, polyamides.

[0058] For the purposes of this invention, the term "major" should be understood to mean that the composition contains at least one polyamide in an amount greater than 50% by weight relative to the total weight of the composition. This or these polyamides constitute the matrix of the composition.

[0059] Preferably, the composition comprises 60% to 98% by weight, preferably 70% to 95% by weight, of at least one polyamide relative to the total weight of the composition.

[0060] polyamide

[0061] In the case of PA-XY type homopolymers, 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 units generated by diamine X and the units generated by diacid Y. Therefore, PA6.12 is a PA with 9 carbon atoms per nitrogen atom, in other words, a C9 PA. PA6.13 is a C... 9.5 PA. In the case of copolyamides, for example, having the structure XaYa / XbYb, the number of carbon atoms per nitrogen atom is calculated according to the same principle. For various amide units, i.e., for XaYa and XbYb units, the calculation is performed in molar proportions.

[0062] The main polyamide present in the composition according to the invention has a number of carbon atoms greater than 6.5, preferably greater than 8, per nitrogen atom.

[0063] For the purposes of this invention, the term "major" means that the composition comprises at least one polyamide in an amount 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 carbon number greater than 6.5 per nitrogen atom. This mixture must be major, meaning that it must account for at least 50% by weight relative to the total weight of the composition.

[0064] Preferably, the composition comprises 60% to 98% by weight, preferably 70% to 95% by weight, of at least one polyamide relative to the total weight of the composition.

[0065] In other words, the presence of other polyamides cannot be excluded. However, it is important that polyamides with a high carbon number are the predominant type in the composition.

[0066] The polyamide present in the composition according to the invention is obtained by polycondensation of at least one unit selected from C6 to C18 α,ω-aminocarboxylic acid, C5 to C12 lactam and (Ca diamine)-(Cb diacid), wherein 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.

[0067] Polyamides can be obtained by polycondensation of at least one lactam selected from pyrrolidone, 2-piperidinone, heptanolactam, 2-azacyclononone, nonanolactam, decanolactam, undecyllactam, and lauryllactam.

[0068] The polyamide present in the composition according to the invention can also be obtained by polycondensation of at least one amino acid selected from 9-aminononanoic acid, 10-aminodecanoic acid (represented by 10), 11-aminoundecanoic acid (represented by 11) and 12-aminododecanoic acid (represented by 12).

[0069] 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.

[0070] The (Ca diamine) unit can be aliphatic, alicyclic, or aromatic. It can 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-phenylenediamine (MXD), methylpentamethylenediamine (MPMD), bis(aminomethyl)cyclohexane (BAC), m-phenylenediamine (MXD, CAS No. 1477-55-0), and p-phenylenediamine (PXD, CAS No. 539-48-0).

[0071] Advantageously, the at least one C6 to C12 diamine X is particularly selected from 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine, 1,10-decamethylenediamine, 1,11-undecamethylenediamine and 1,12-dodecimethylenediamine.

[0072] Advantageously, the diamine X used is a C10 to C12 diamine, particularly selected from 1,10-decamethylenediamine, 1,11-undecamethylenediamine and 1,12-dodecimethylenediamine.

[0073] The (Cb diacid) unit can be aliphatic, alicyclic, or aromatic. It can be selected from succinic acid (b=4), glutaric acid (b=5), adipic acid (b=6), pimelic acid (b=7), octanoic acid (b=8), azelaic acid (b=9), sebacic acid (b=10), undecanoic acid (b=11), dodecanoic acid (b=12), tridecanoic acid (b=13), tetradecanoic acid (b=14), hexadecanoic acid (b=16), octadecanoic acid (b=18), and diacids obtained from fatty acids, and terephthalic acid (denoted as T).

[0074] Advantageously, the (Cb diacid) unit is selected from diacid, octanoic acid, azelaic acid, sebacic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid and octadecanoic acid.

[0075] Advantageously, the polyamide present in the composition according to the invention has an elongation at break of >50%, preferably greater than 100%, and even more advantageously greater than 200%. The elongation at break can be notably measured according to standard ISO 527-1 / -2.

[0076] Advantageously, the composition according to the invention comprises less than 25% by weight of polyamide having an elongation at break of less than or equal to 50%, preferably less than 10% by weight, more preferably less than 5% by weight, and more preferably less than 1% by weight, relative to the total weight of the composition. Preferably, the composition according to the invention does not contain any polyamide having an elongation at break of less than or equal to 50%.

[0077] Advantageously, the polyamide present in the composition according to the invention is aliphatic or alicyclic, preferably aliphatic.

[0078] Advantageously, the polyamide present in the composition according to the invention is selected from PA 11, PA 12, PA 1010, PA 1012, PA 610, PA 612, PA 516, PA 613, PA 912, PA 6 / 11, PA 6 / 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 and PA 6 / 1010 / 1012 / 1014, alone or as a mixture.

[0079] Preferably, the composition contains only polyamides with more than 6.5 carbon atoms per nitrogen atom. More particularly, the composition contains only polyamides with more than 8 carbon atoms per nitrogen atom.

[0080] According to a preferred embodiment, the polyamide present in the composition according to the invention is a homopolymer. This homopolymer can be obtained by polycondensation of lactam, amino acid, or (Ca diamine)(Cb diacid) units, wherein Ca and Cb are as defined above.

[0081] More specifically, the composition mainly comprises PA11, PA12, PA1010, PA1012, or even more preferably PA11 or PA12, with PA11 being the most preferred.

[0082] PA11 has the advantage of being made from plant-derived raw materials. Plant materials can be grown in large quantities in most parts of the world as needed and are bio-based. Bio-based raw materials are natural animal or plant resources whose reserves can be reconstructed in a short time on a human timescale. Of particular importance is that these reserves can be regenerated as quickly as they are consumed.

[0083] The basic raw material for PA11 is castor oil, which is extracted from the seeds of the castor oil plant (Ricinus communis). PA11 is obtained through the condensation polymerization of 11-aminoundecanoic acid.

[0084] Total acidity and total alkalinity

[0085] The difference (expressed in absolute value) between the total acidity and the total basicity of the polyamide present in the composition according to the invention is strictly less than 70, preferably less than 50, and ideally less than 30.

[0086] For the purposes of this invention, the term difference is expressed in absolute value and should be understood as the result of subtracting the total basicity value of the polyamide from the total acidity value of the polyamide, regardless of the sign.

[0087] When the composition contains a mixture of polyamides, the acidity and alkalinity of the polyamide mixture are measured. Therefore, the difference is expressed as a percentage of the polyamide mixture.

[0088] The polyamide present in the composition according to the invention also has a total alkalinity of strictly less than 60 μeq / g, preferably less than 50 μeq / g, and ideally less than 40 μeq / g.

[0089] Preferably, the polyamide present in the composition according to the invention also has a total acidity of strictly less than 60 μeq / g, preferably less than 50 μeq / g, and ideally less than 40 μeq / g.

[0090] Acidity and alkalinity are measured by potentiometric method.

[0091] Acidity was measured using the following method: The polyamide sample was dissolved in benzyl alcohol. The sample was then analyzed by potentiometry using a 0.02 N tetrabutylammonium hydroxide solution.

[0092] Alkalinity was measured using the following method: The polyamide sample was dissolved in m-cresol. The sample was then analyzed using a potentiometry method with 0.02 N perchloric acid solution.

[0093] According to one embodiment of the invention, the polyamide has a total basicity strictly less than 60 μeq / g and a total acidity strictly less than 60 μeq / g, and a difference in absolute value between its total acidity and its total basicity strictly less than 50, ideally less than 30.

[0094] According to a preferred embodiment, the composition according to the invention mainly comprises PA11, PA12, PA1010 or PA1012 and mixtures thereof, wherein such polyamide or these polyamides have a total basicity of less than 60 μeq / g and a difference in absolute value between their total acidity and total basicity that is strictly less than 50 and ideally less than 30.

[0095] According to a preferred embodiment, the composition according to the invention mainly comprises PA11 or PA12, having a total alkalinity of less than 50 μeq / g and a total acidity of less than 60 μeq / g, and a difference in absolute value between its total acidity and its total alkalinity that is strictly less than 30.

[0096] Preferably, the polyamide present in the composition does not contain chain restrictors.

[0097] Intrinsic viscosity

[0098] Preferably, the polyamide according to the invention has an intrinsic viscosity greater than 1.1, and more preferably greater than 1.2, according to standard ISO 307:2007.

[0099] A 75 mg sample containing 0.5% (m / m) m-cresol was measured at 20°C.

[0100] When the composition contains a mixture of polyamides, the viscosity of the polyamide mixture is measured.

[0101] enthalpy of melting

[0102] Preferably, the polyamide has a melting enthalpy greater than 20 J / g, preferably greater than 30 J / g, and ideally greater than 40 J / g.

[0103] The enthalpy of fusion was measured by DSC (differential scanning calorimetry) according to standard ISO 11357-3:2013 (a second DSC heating run was performed at 20°C / min according to ISO 11357).

[0104] When the composition contains a mixture of polyamides, the enthalpy of melting of the polyamide mixture is measured.

[0105] Crystallization temperature

[0106] Preferably, the polyamide mixture has a crystallization temperature below 180°C, and more preferably below 160°C.

[0107] Crystallization temperature was measured by DSC (differential scanning calorimetry) according to standard ISO 11357-3:2013 (a second DSC heating run was performed at 20°C / min according to ISO 11357).

[0108] When the composition contains a mixture of polyamides, the crystallization temperature of the polyamide mixture is measured.

[0109] Colorant

[0110] The compositions according to the invention comprise at least one colorant. The colorant may be a dye or a pigment, in other words, a water-soluble dye or a pigment that is insoluble in water under the conditions defined below.

[0111] The dye can be any type known to those skilled in the art. Preferably, the dye according to the invention is selected from azo dyes, anthraquinone dyes, indigo dyes, triarylmethane dyes, chloro dyes, and polymethystine dyes.

[0112] The term "pigment" refers to any pigment that imparts color to a polymer composition. They have a solubility in water of less than 0.05% by weight, preferably less than 0.01%, at 25°C and atmospheric pressure (760 mmHg). Pigments that can be used are particularly selected from organic and / or inorganic pigments known in the art, especially those described in Kirk-Othmer's Encyclopedia of Chemical Technology and Ullmann's Encyclopedia of Industrial Chemistry.

[0113] Pigments can be of natural or non-natural origin. They can be in powder or pigment paste form. They can be coated or uncoated. Pigments can be selected from, for example, inorganic pigments, organic pigments, and mixtures thereof.

[0114] The term "inorganic pigment" refers to any pigment that meets the definition in the chapter on inorganic pigments in the Ullmann Encyclopedia. Among the inorganic pigments that can be used in this invention, references may be made to ochre, such as red ochre (clay (especially kaolinite) and iron hydroxide (e.g., hematite)), brown ochre (clay (especially kaolinite) and goethite), yellow ochre (clay (especially kaolinite) and goethite); titanium dioxide, optionally surface-treated; 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 or copper powder. References may also be made to carbonates of alkaline earth metals (e.g., calcium or magnesium), silica, quartz, and any other compounds used as inert fillers in cosmetic compositions, provided that these compounds provide the color or whiteness of the composition under the conditions of their use.

[0115] Preferably, the compositions of the present invention do not contain any salts of the aforementioned metals, particularly aluminum or copper salts.

[0116] Pigments can be organic pigments. The term "organic pigment" refers to any pigment that meets the definition in the "Organic Pigments" section of the Ullmann Encyclopedia.

[0117] Organic pigments can be notably selected from nitroso compounds, nitro compounds, azo compounds, xanthracene compounds, pyrene compounds, quinoline compounds, anthraquinone compounds, triphenylmethane compounds, fluorane compounds, phthalocyanine compounds, metal complex compounds, isoindolineone compounds, isoindoline compounds, quinacridone compounds, perylene compounds, perylene compounds, diketopyrrolopyrrole compounds, indigo compounds, thioindigo compounds, dioxazine compounds, triphenylmethane compounds, and quinoline phthalocyanine compounds.

[0118] Specifically, white or colored organic pigments may be selected from carmine, carbon black, aniline black, azo yellow, quinacridone, phthalocyanine, blue pigments coded in the Color Index with index numbers CI 42090, 69800, 69825, 74100, 74160, blue pigments coded in the Color Index with index numbers CI 11680, 11710, 19140, 20040, 21100, 21108, 47000, 47005, yellow pigments coded in the Color Index with index numbers CI 61565, 61570, 74260, orange pigments coded in the Color Index with index numbers CI 11725, 45370, 71105, and others. The red pigments in the Index are coded with index numbers CI12085, 12120, 12370, 12420, 12490, 14700, 15525, 15580, 15620, 15630, 15800, 15850, 15865, 15880, 26100, 45380, 45410, 58000, 73360, 73915, and 75470.

[0119] Advantageously, the pigments are selected from pigments CIPigment Orange 82 [CAS No. 2170864-77-2] and CIPigment Yellow [CAS No. 817181-98-9]. Pigment Orange 82 can be obtained, for example, under the name Sicopal® Pigment Orange K2430 from Sun Chemical, Ludwigshafen, Germany. Pigment Yellow 216 can be obtained, for example, under the name Orange 10P340 from Shepherd, Ghent, Belgium.

[0120] Carmine acid may be mentioned in the dyeing agents. Dyes known by the following names may also be 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), and D&C Blue 1 (CI 42 090).

[0121] Colorants can be selected from 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.

[0122] According to one embodiment, the composition according to the invention contains less than 1% by weight, notably less than 0.1% by weight, of carbon-based filler relative to the total weight of the composition.

[0123] For the purposes of this invention, the term "carbon-based filler" refers to particulate matter containing only carbon atoms in its mass, "other than impurities," meaning that other atoms may be present on the surface. Carbon-based fillers may be selected from, but are not limited to, carbon black, natural and synthetic graphite, carbon fibers, graphene, fullerene, acetylene black, and carbon nanotubes.

[0124] According to any embodiment, the composition according to the invention contains less than 0.1% by weight of carbon black relative to its total weight. Preferably, the composition according to the invention contains no carbon black.

[0125] Preferably, the composition according to the invention comprises at least one colorant that produces a color other than black.

[0126] Preferably, the composition according to the invention comprises less than 1% by weight, noteworthyly less than 0.1% by weight, and preferably 0% by weight of L having a content of less than 10, particularly less than 5, particularly less than 1, and noteworthyly equal to 0, relative to its total weight. The colorant of the parameter, where L The parameters were measured in reflectance mode using a Konica Minolta CM-36dGV spectrophotometer in the CIELab system as defined in standard ISO 11664-4:2008, with a D65 light source, an incident angle of 10°, and an aperture of 8 mm, and including the specular component.

[0127] Preferably, the selected colorant results in the composition having:

[0128] - L between 10 and 100, preferably between 20 and 80, advantageously between 40 and 75, and noteworthyly between 50 and 70 Parameters, and / or

[0129] - a between 10 and 100, preferably between 20 and 80, advantageously between 35 and 55 Parameters, and / or

[0130] - Between 10 and 100, preferably between 20 and 80, advantageously between 40 and 75, and noteworthyly between 50 and 70. parameter,

[0131] Wherein L a and b The parameters were measured in reflection mode using a Konica Minolta CM-36dGV spectrophotometer in the CIELab system as defined in standard ISO 11664-4:2008, with a D65 light source, an incident angle of 10°, an aperture of 8 mm, and including the specular component.

[0132] Preferably, the coating composition includes at least one colorant that causes orange color.

[0133] Preferably, the selected dyes result in the color of RAL 2003, i.e., they have the following L a b Value: L =66.0; a =41.2 and b =52.4.

[0134] 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 other pigments, preferably producing an orange color.

[0135] Preferably, the colorant content in the composition is from 0.5% to 10% by weight, advantageously from 1% to 5% by weight, relative to the total weight of the composition.

[0136] Preferably, the content of black dye, and notably black pigment, carbon black or other black filler is limited to a maximum of 0.1% by weight.

[0137] Preferably, black colorant is excluded.

[0138] Preferably, the color of the composition is characterized in that the color measured by the RAL method is different from RAL colors 2100, 6015, 7021, 8022, 9004, 9005, 9011, 9017 or 9021.

[0139] Preferably, the composition according to the invention comprises 60% to 98% by weight, preferably 70% to 95% by weight, of polyamide and 0.5% to 10% by weight, preferably 1% to 5% by weight, of colorant.

[0140] additive

[0141] Preferably, the composition according to the invention comprises at least one additive selected from flame retardants, UV protectants, UV stabilizers, heat stabilizers, lubricants, flow improvers, pourability improvers, film-forming agents, fillers, film-forming aids, colloids, preservatives, antibacterial agents, and mixtures thereof. Preferably, the composition according to the invention does not contain any metal-based additives to avoid any harmful interactions between the metal surface to be coated and these additives that may be present in the composition according to the invention.

[0142] antioxidants

[0143] Preferably, the composition according to the invention comprises at least one antioxidant.

[0144] For example, stabilizers can be organic stabilizers or, more generally, combinations of organic stabilizers, such as phenolic antioxidants (e.g., Irganox® 245, 1098, or 1010 types from Ciba-BASF), or phosphite-type antioxidants (e.g., Irgafos® 126 or Irgafos® 168 from Ciba-BASF), and even optional other stabilizers, such as HALS, which refers to hindered amine light stabilizers (e.g., Tinuvin® 770 from Ciba-BASF), UV stabilizers (e.g., Tinuvin® 312 from Ciba-BASF), or phosphorus-based stabilizers. Amine-type antioxidants, such as Naugard® 445 from Crompton, or multifunctional stabilizers, such as Nylostab® S-EED from Clariant, can also be used.

[0145] Therefore, the composition according to the invention exhibits color stability after thermal aging at 150°C for 150 h, which is expressed as ΔE < 10 for a 1 mm thick plate composed of the composition. The color stability after thermal aging at 150°C for 150 h is expressed as ΔE < 20 for a 1 mm thick plate covering a copper substrate.

[0146] In another embodiment, the composition as defined above has a yield stress of <60 MPa, preferably <50 MPa.

[0147] In yet another embodiment, the composition as defined above has a yield elongation of >3%, advantageously >4%, as measured according to standard ISO 527-1 / 2:2012.

[0148] Advantageously, the composition has good abrasion resistance as measured according to standard ISO 9352:2012. Advantageously, the composition of the present invention has an electrical insulating effect after coating, and has a high dielectric strength (greater than 20 kV / mm, advantageously greater than 25 kV / mm) at 23°C as measured according to standard IEC 60243-1:2013.

[0149] Advantageously, as measured according to standard IEC 60243-1:2013, the composition as defined above has high dielectric strength (>5kV / mm) at 90°C.

[0150] Advantageously, the composition as defined above has a relative tracking index (CTI) of >600 V as measured according to IEC 60112:2020. This insulation is maintained during accelerated thermal aging, which can reach up to 130°C, and notably up to 150°C.

[0151] Advantageously, the composition of the present invention has an electrical insulating effect after coating, with a breakdown voltage of >20kV under direct current (DC) and >10kV under alternating current (AC) for a thickness of 500 μm, and a relative tracking index (CTI) of >600V.

[0152] use

[0153] According to another aspect, the present invention relates to the use of the composition as defined above for covering power transmission components, preferably battery busbars.

[0154] All the features defined above are valid for this purpose.

[0155] The composition of the present invention allows the busbar to be covered with a thin layer of 0.1 mm to 2 mm, particularly 0.2 mm to 1 mm, notably 0.3 mm to 0.8 mm, and more particularly 0.4 mm to 0.6 mm, while maintaining a high level of flexibility to accommodate deformation of the busbar.

[0156] Overly rigid materials can cause cracks or "ripples" that are unacceptable for the application.

[0157] Power transmission components

[0158] The present invention also relates to a power transmission component comprising:

[0159] - Power transmission components with metallic surfaces, and

[0160] - A coating made from the composition as defined above.

[0161] Preferably, the metal surface is made of copper, copper alloy, aluminum, or aluminum alloy, and more preferably of copper and copper alloy.

[0162] Preferably, the coating thickness is 0.1 mm to 2 mm, particularly 0.2 mm to 1 mm, notably 0.3 mm to 0.8 mm, and even more particularly 0.4 mm to 0.6 mm.

[0163] According to one specific embodiment of the present invention, the coating is in direct contact with the metal surface.

[0164] According to another embodiment, the power transmission component includes an intermediate layer located between the metal surface and the coating.

[0165] Intermediate layer

[0166] According to one specific embodiment, the intermediate layer is located between the metal surface and the composition according to the invention.

[0167] The intermediate layer can be a cross-linked adhesive primer layer, a metal layer, or a polyolefin layer.

[0168] Intermediate layer of cross-linking adhesive primer

[0169] In the first embodiment, the intermediate layer is a cross-linked adhesive primer layer. Preferably, this layer completely covers the metal surface.

[0170] The adhesive primer is specifically as defined in standard ISO 12944-5:2018. Preferably, the adhesive primer contains acrylic polymers, saturated or unsaturated polyesters, alkyd resins, polyurethanes, polyethers, polyvinyl alcohols, cellulose or silicone products, copolymers thereof, or mixtures thereof. Preferably, the adhesive primer contains reactive groups, such as epoxide, carboxylic acid, hydroxyl, isocyanate, amide, urethane, amine, or carboxylic acid ester groups, or mixtures thereof.

[0171] Preferably, the adhesive primer is a compound composition comprising epoxy, urethane, acrylic, and / or polyester functional groups. Preferably, the adhesive primer is an epoxy acrylate composition (e.g., PrimGreen L.AT12035 sold by Arkema).

[0172] After deposition on a metal surface, or preferably on a metal strip, the primer composition crosslinks. Crosslinking can be carried out in any manner known to those skilled in the art, by a crosslinking initiator or catalyst, by solvent evaporation, and particularly by heating or by UV irradiation. The heating temperature used for crosslinking will depend on the adhesive primer used; for example, in the case of an epoxy acrylate adhesive primer, the crosslinking temperature may be about 300°C.

[0173] Crosslinking can occur according to two crosslinking modes. According to a first embodiment, the adhesive primer may consist of a base resin first applied to a metal surface and a crosslinking agent applied subsequently. The crosslinking agent enables the base resin to crosslink, which is initiated, for example, by a heating step. According to a second embodiment, the adhesive primer is a self-crosslinking compound. It is a base resin having crosslinking functional groups.

[0174] The cross-linked adhesive primer layer preferably has a thickness of 2-100 μm, more preferably 5-50 μm.

[0175] Of particular advantage, the cross-linked adhesive primer layer allows for stable color retention over time, even at high temperatures, while maintaining mechanical strength and adhesion between the coating and the metal surface. Furthermore, it has been shown that the presence of the adhesive primer layer enables resistance to salt spray corrosion.

[0176] Metal Interlayer

[0177] In the second embodiment, the intermediate layer is a metal layer. Preferably, this layer completely covers the metal surface of the power transmission component.

[0178] Preferably, the metal of the intermediate layer can be of any type, as long as it is not copper or a copper alloy.

[0179] Preferably, the metal interlayer can be a layer of chromium, nickel, zinc, tin, manganese, aluminum, platinum, gold, silver, or an alloy of these metals.

[0180] A metal interlayer can be formed on the metal surface of a power transmission component by any method known to those skilled in the art. The metal interlayer can be obtained by electroplating or depositing a metal foil or by plasma-enhanced chemical vapor deposition on the metal surface of the power transmission component. Electroplating is a well-known technique that involves immersing the metal component to be coated in a solution containing metal ions of a metal selected for the interlayer, applying an electric current, and then depositing the metal ions onto the metal surface of the power transmission component. The metal interlayer can also be chromium and can be produced by chromate treatment techniques. The metal interlayer can also be a metal phosphate salt layer obtained by phosphate treatment.

[0181] The metal interlayer preferably has a thickness of 0.1 to 10 μm, more preferably 0.5 to 5 μm.

[0182] Advantageously, the metal interlayer allows for stable color retention over time, even at high temperatures, while maintaining mechanical strength.

[0183] Polyolefin interlayer

[0184] In the third embodiment, the intermediate layer is a polyolefin layer. Preferably, this layer completely covers the metal surface of the power transmission component.

[0185] The polyolefin is preferably selected from functionalized and nonfunctionalized polyolefins and mixtures thereof.

[0186] For simplicity, polyolefins are represented by (B), and functionalized polyolefins (B1) and nonfunctionalized polyolefins (B2) have been described below.

[0187] Nonfunctionalized polyolefins (B2) are typically homopolymers or copolymers of α-olefins or dienes (e.g., ethylene, propylene, 1-butene, 1-octene, or butadiene). Examples that may be mentioned include:

[0188] - Homopolymers and copolymers of polyethylene, especially LDPE, HDPE, LLDPE (linear low-density polyethylene), VLDPE (very low-density polyethylene), and metallocene polyethylene.

[0189] -Propylene homopolymer or copolymer

[0190] 1-Ethylene / α-olefin copolymers, such as ethylene / propylene, EPR (abbreviation for ethylene-propylene rubber), and ethylene / propylene / diene (EPDM).

[0191] - Styrene / ethylene-butene / styrene (SEBS), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), and styrene / ethylene-propylene / styrene (SEPS) block copolymers,

[0192] - A copolymer of ethylene with at least one salt or ester of an unsaturated carboxylic acid, such as an alkyl ester of (meth)acrylate (e.g., methyl acrylate) or a vinyl ester of a saturated carboxylic acid, such as vinyl acetate (EVA), wherein the proportion of comonomers can be up to 40% by weight.

[0193] Preferably, the functionalized polyolefin (B1) is a polymer of an α-olefin having a reactive unit (functional group); such reactive unit is an acid, anhydride, or epoxy functional group. For example, the aforementioned polyolefin (B2) can be mentioned as being grafted or copolymerized or ternarily copolymerized with an unsaturated epoxide such as glycidyl (meth)acrylate, or with a carboxylic acid or its corresponding salt or ester such as (meth)acrylic acid (which can be completely or partially neutralized with a metal such as Zn), or with a carboxylic anhydride such as maleic anhydride. The functionalized polyolefin is, for example, a PE / EPR blend, the weight ratio of which can vary over a wide range, for example between 40 / 60 and 90 / 10, said blend being co-grafted with anhydride, particularly maleic anhydride, to a grafting degree of, for example, 0.01% by weight to 5% by weight.

[0194] Preferably, the functionalized polyolefin (B1) is selected from the following (co)polymers grafted with maleic anhydride or glycidyl methacrylate, wherein the grafting degree is, for example, from 0.01% by weight to 5% by weight:

[0195] -PE, PP, copolymers of ethylene with propylene, butene, hexene or octene, containing, for example, 35% to 80% by weight of ethylene;

[0196] - Ethylene / α-olefin copolymers, such as ethylene / propylene, EPR (abbreviation for ethylene-propylene rubber) and ethylene / propylene / diene (EPDM).

[0197] - Styrene / ethylene-butene / styrene (SEBS), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), and styrene / ethylene-propylene / styrene (SEPS) block copolymers;

[0198] - Ethylene / vinyl acetate (EVA) copolymer, containing up to 40% by weight of vinyl acetate;

[0199] - Ethylene / (meth)acrylate copolymer, containing up to 40% by weight of (meth)acrylate;

[0200] - A copolymer of ethylene / vinyl acetate (EVA) and (meth)acrylate alkyl esters, containing up to 40% by weight of comonomer.

[0201] Preferably, the functionalized polyolefin (B1) is selected from ethylene / propylene copolymers, primarily propylene, grafted with maleic anhydride, and then condensed with a monoamino polyamide (or a polyamide oligomer) (the product described in EP-A-0342066).

[0202] Preferably, the functionalized polyolefin (B1) is a copolymer or terpolymer of at least the following units: (1) ethylene, (2) alkyl methacrylate or vinyl saturated carboxylic acid and (3) anhydride, such as maleic anhydride or (meth)acrylic anhydride, or epoxy, such as glycidyl methacrylate.

[0203] As an example of the latter type of functionalized polyolefin, the following copolymers can be mentioned, wherein ethylene preferably accounts for at least 60% by weight of the copolymer, and wherein the terpolymeric comonomer (functional group) accounts for, for example, 0.1% to 10% by weight of the copolymer:

[0204] - Ethylene / (meth)acrylate alkyl ester / (meth)acrylic acid or maleic anhydride or glycidyl methacrylate copolymer;

[0205] - Ethylene / vinyl acetate / maleic anhydride or glycidyl methacrylate copolymer;

[0206] - Ethylene / vinyl acetate or (meth)acrylate alkyl ester / (meth)acrylic acid or maleic anhydride or glycidyl methacrylate copolymer.

[0207] In the aforementioned copolymers, (meth)acrylic acid can be salted using Zn or Li.

[0208] The term “(meth)acrylate alkyl ester” in (B1) or (B2) means C1-C8 alkyl methacrylate and C1-C8 alkyl acrylate, and may be selected from methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, methyl methacrylate and ethyl methacrylate.

[0209] Preferably, the polyolefin (B1) can also be crosslinked by any suitable method or reagent (diepoxide, diacid, peroxide, etc.); the term "functionalized polyolefin" also includes a mixture of the polyolefin and a bifunctional reagent (e.g., diacid, dianhydride, diepoxide, etc.) capable of reacting with these polyolefins, or a mixture of at least two functionalized polyolefins capable of reacting with each other.

[0210] Preferably, the copolymers (B1) and (B2) are copolymerized in a random or block manner and have a linear or branched structure.

[0211] The molecular weight, MFI index, and density of these polyolefins can vary over a wide range, as those skilled in the art will understand. MFI is an abbreviation for Melt Flow Index. It is measured according to the standard ASTM 1238.

[0212] Preferably, the nonfunctionalized polyolefin (B2) is selected from polypropylene homopolymers or copolymers and any ethylene homopolymer or copolymer of ethylene with a higher α-olefin type comonomer (e.g., butene, hexene, octene, or 4-methyl-1-pentene). Examples of suitable polyolefins include PP, high-density PE, medium-density PE, linear low-density PE, low-density PE, very low-density PE, styrene / ethylene-butene / styrene (SEBS), and styrene / ethylene-propylene / styrene (SEPS) block copolymers. Those skilled in the art know that these polyethylenes are produced according to a "free radical" method, according to a "Ziegler" type catalysis, or more recently according to a "metallocene" catalysis.

[0213] Preferably, the functionalized polyolefin (B1) is selected from any polymer comprising α-olefin units and units with polar reactive functional groups (e.g., epoxy, carboxylic acid, or carboxylic anhydride functional groups). Examples of such polymers include terpolymers of ethylene, alkyl acrylate, and maleic anhydride or glycidyl methacrylate, such as Lotader® products (SK Functional Polymer), or polyolefins grafted with maleic anhydride, such as Orevac® products (SK Functional Polymer), and terpolymers of ethylene, alkyl acrylate, and (meth)acrylic acid. Also mentioned are polypropylene homopolymers or copolymers grafted with carboxylic anhydride and then condensed with polyamide or monoamino polyamide oligomers.

[0214] In one implementation, the polyolefin is functionalized.

[0215] Advantageously, the nonfunctionalized polyolefin is selected from polyethylene and polypropylene, especially polyethylene, particularly low-density polyethylene (LDPE).

[0216] The polyolefin layer preferably has a thickness of 10 to 1000 μm, more preferably 30 to 500 μm, and advantageously 50 to 300 μm.

[0217] Of particular advantage, the polyolefin layer allows the color to remain stable over time, even at high temperatures, while maintaining good adhesion and mechanical strength of the coating.

[0218] Any other organic polymer can be used to replace the polyolefin layer according to the invention.

[0219] According to another embodiment, the coating made of the composition as defined above is the outermost layer of the component. The power transmission component can be of any type. It is primarily a high-voltage power transmission component. The component can be in the form of a metal cable or a cable containing metal fibers (e.g., braided metal fibers), or in the form of thin, stacked metal sheets, or in the form of metal strips, such as those commonly used in busbars.

[0220] Preferably, the power transmission component is an electrical or electronic component cover, control device, connector, battery relay, electrical housing, electrical terminal, or cable.

[0221] Preferably, the power transmission component is a busbar.

[0222] In one embodiment, the busbar is located inside and / or outside the battery, particularly in a vehicle battery, especially in a motor vehicle battery. For example, it may be immersed in coolant.

[0223] Method for manufacturing power transmission components

[0224] According to another aspect, the present invention relates to a method for manufacturing a power transmission component, comprising the step of covering the metal surface of the power transmission component with a composition as defined above.

[0225] Preferably, the present invention relates to a method for preparing a busbar, comprising the step of covering the metal surface of a power transmission component with a composition as defined above.

[0226] The coating step may be a step of extruding the composition as defined above onto the metal surface of the power transmission component, or a step of coating the composition powder onto the metal surface of the power transmission component.

[0227] Preferably, the preparation method does not include the step of coating the composition powder onto the battery busbar.

[0228] Before being coated with the composition according to the invention, the metal surface may undergo a pretreatment step. Therefore, prior to the coating step, the method may include a degreasing step and / or a flame treatment step and / or a preheating step on the metal surface.

[0229] Preferably, the power transmission component is a battery busbar.

[0230] The metal strip can be solid. However, it can also be made up of multiple braided metal wires, which gives it great flexibility.

[0231] Cross-linked adhesive primer intermediate layer

[0232] According to another embodiment, the present invention relates to a method for manufacturing a power transmission component, preferably a busbar, notably for a battery busbar, the method comprising:

[0233] - Coat the entire metal surface of the power transmission component, preferably the busbar, with an intermediate layer of adhesive primer as defined above, and then crosslink the layer;

[0234] - The step of extruding the coating composition as defined above onto a metal surface that has previously been covered with an adhesive primer layer.

[0235] Preferably, after applying the adhesive primer layer, the method includes an additional step of evaporating the solvent, followed optionally by a curing step, a heating step, or a UV irradiation step. Depending on the chosen adhesive primer, this step may cause the primer to crosslink. The metal surface of the power transmission component, preferably the metal strip of the busbar, may undergo a pretreatment step before being covered with an intermediate primer layer. The method may include, for example, a degreasing step and / or a flame treatment step and / or a preheating step on the metal surface.

[0236] Metal Interlayer

[0237] According to another embodiment, the present invention relates to a method for manufacturing a power transmission component, preferably a busbar, notably for a battery busbar, the method comprising:

[0238] - Coat the metal surface of the power transmission component, preferably the metal surface of the busbar, with the metal interlayer as defined above;

[0239] - The step of extruding the coating composition as defined above onto a metal surface that has previously been covered with a metal interlayer.

[0240] Preferably, the metal intermediate layer is deposited on the metal surface of the power transmission component by electroplating, as described above.

[0241] The metal surface of a power transmission component, preferably the metal strip of a busbar, may undergo a pretreatment step before being covered with a metal interlayer. This method may include, for example, a degreasing step and / or a flame treatment step and / or a preheating step on the metal surface.

[0242] Polyolefin interlayer

[0243] According to another embodiment, the present invention relates to a method for manufacturing a power transmission component, preferably a busbar, notably particularly for a battery busbar, the method comprising:

[0244] - The step of coating the power transmission component with a polyolefin interlayer as defined above, preferably the entire metal surface of the busbar;

[0245] - The step of coating a polyolefin intermediate layer with the coating composition as defined above.

[0246] Preferably, the step of coating the polyolefin intermediate layer with the coating composition as defined above can be performed by extruding the composition or by depositing powder of the coating composition and then melting the powder.

[0247] Preferably, the preparation method includes an extrusion step but does not include a powder coating step.

[0248] It is possible that the metal surface of the power transmission component (preferably the metal strip of the busbar) undergoes a pretreatment step before being covered with a polyolefin interlayer. This method may include, for example, a degreasing step and / or a flame treatment step and / or a preheating step on the metal surface.

[0249] All the features defined above are valid for this method.

[0250] Other objects and advantages of the invention will become apparent from the following embodiments, which are given without any implied limitations.

[0251] Example

[0252] Example 1

[0253] Preparation of the composition

[0254] Compositions and comparative compositions according to the present invention were prepared using the following compounds.

[0255] The polyamide according to the invention, designated PA 11 A, 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 loaded into an autoclave and heated at 250°C while maintaining autogenous pressure for 30 minutes. Once the monomers are melted, the mixture is stirred at 40 rpm throughout the synthesis. Gradual expansion is applied for 2 hours up to 1 bar, while the temperature is raised to 255°C. The system is then flushed with nitrogen at a flow rate of 100 L / h for 30 minutes while maintaining the temperature at 255°C. Finally, stirring is stopped and the molten material is extruded at a pressure of 6 bar. The rods are cooled in a water bath and then granulated.

[0256] The polyamide designated PA 11 B was prepared according to the following method: 33.00 kg of 11-aminoundecanoic acid, 79.8 g of potassium hydroxide, and 5.5 kg of deionized water were charged into an autoclave and heated at 220°C while maintaining autogenous pressure for 1 hour. Once the monomers were melted, the mixture was stirred at 40 rpm throughout the synthesis. Gradual expansion was applied for 75 minutes up to 10 bar while raising the temperature to 260°C. Next, expansion was applied for 2 hours over one hour up to 0.3 bar while maintaining the temperature at 260°C. The system was then flushed with nitrogen at a flow rate of 100 L / h for 30 minutes while maintaining the temperature at 255°C. Finally, stirring was stopped, and the molten material was extruded at a pressure of 10 bar. The rods were cooled in a water bath and then granulated.

[0257] The polyamide designated PA 11 C was prepared according to the following method: 26.35.00 kg of 11-aminoundecanoic acid, 0.214 kg of adipic acid, and 5.40 kg of deionized water were charged into an autoclave and heated to 235°C while maintaining autogenous pressure for 90 minutes. Once the monomers melted, the mixture was stirred at 40 rpm throughout the synthesis. Gradual expansion was applied for 2 hours up to 0.3 bar while maintaining the temperature at 235°C. The system was then flushed with nitrogen at a flow rate of 100 L / h for 90 minutes while maintaining the temperature at 260°C. Finally, stirring was stopped and the molten material was extruded at a pressure of 6 bar. The rods were cooled in a water bath and then granulated.

[0258] The polyamide according to the invention, designated PA 12 A, is prepared according to the following method: 25.00 kg of laurolactam and 2.20 kg of deionized water are charged into an autoclave and heated at 290°C for 5 hours at a pressure of 32 bar. Once the monomers are melted, the mixture is stirred at 40 rpm throughout the synthesis. Gradual expansion is applied for 8 hours up to 8 bar while maintaining the temperature at 290°C. Next, expansion is applied for one hour up to 0.2 bar while gradually decreasing the temperature to 265°C. The system is then flushed with nitrogen at a flow rate of 100 L / h for 15 minutes while maintaining the temperature at 265°C. Finally, a vacuum is applied to reach a pressure of 0.3 bar for 15 minutes. Finally, stirring is stopped and the molten material is extruded at a pressure of 10 bar. The rods are cooled in a water bath and then granulated.

[0259] The polyamide designated PA 12 B was prepared according to the following procedure: 30.00 kg of laurolactam, 0.160 kg of adipic acid, and 2.00 kg of deionized water were charged into an autoclave and heated at 290°C for 5 hours at a pressure of 32 bar. Once the monomers were melted, the mixture was stirred at 40 rpm throughout the synthesis. Gradual expansion was applied for 8 hours up to 8 bar while maintaining the temperature at 290°C. Next, expansion was applied for one hour up to 0.2 bar while gradually decreasing the temperature to 265°C. The system was then flushed with nitrogen at a flow rate of 100 L / h for 15 minutes while maintaining the temperature at 265°C. Finally, a vacuum was applied to reach a pressure of 0.3 bar for 15 minutes. Finally, stirring was stopped, and the molten material was extruded at a pressure of 10 bar. The rods were cooled in a water bath and then granulated.

[0260] A mixture of polyamides was prepared by melt blending of polyamides. The mixture consisted of 84 wt% PA 11 A and 16 wt% PA 11 B.

[0261] The tested polyamides and polyamide mixtures have the characteristics shown in Table 1 below:

[0262] Table 1

[0263] Measurement of total alkalinity

[0264] Alkalinity was measured as follows: 1 g of polyamide was dissolved in 80 ml of m-cresol at high temperature. The sample was then cooled. Next, the alkalinity was determined by potentiometry using a Metrohm titrator (888 or 716) with a combined pH electrode and an acetic acid solution containing 0.02 N perchloric acid. The graph of potential as a function of volume shows the jump with equivalent volume, from which the total alkalinity can be calculated using the following formula:

[0265]

[0266] Where Viq represents the equivalent volume obtained by potentiometric measurement, and [HClO4] represents the concentration of the perchloric acid solution, i.e., 0.02 N.

[0267] m represents the mass of the sample, i.e., 1g.

[0268] Measurement of total acidity

[0269] Acidity was measured as follows: 1 g of polyamide was dissolved in 80 ml of benzyl alcohol at high temperature. The sample was then cooled. Next, the acidity was determined by potentiometry using a Metrohm titrator (888 or 716) with a combined pH electrode and a 0.02 N tetrabutylammonium hydroxide solution. The graph of potential as a function of volume shows the abrupt change with equivalent volume, from which the total acidity can be calculated using the following formula:

[0270]

[0271] in

[0272] Veq represents the equivalent volume obtained by potentiometric titration.

[0273] [TBAOH] indicates the concentration of the tetrabutylammonium hydroxide solution, i.e., 0.02N.

[0274] m represents the mass of the sample, i.e., 1g.

[0275] Calculation of the difference between total acidity and total alkalinity

[0276] The difference between the total acidity and total alkalinity is obtained by subtracting the values ​​of total acidity and total alkalinity, and is taken as the absolute value, i.e., the sign is not considered.

[0277] For example, for PA11A:

[0278]

[0279] Measurement of intrinsic viscosity

[0280] A 75 mg sample containing 0.5% (m / m) m-cresol was measured at 20°C. The intrinsic viscosity was calculated using the following formula:

[0281] Intrinsic viscosity = ln(t) s / t0)x 1 / C, where C=m / px 100,

[0282] in:

[0283] t s t0 is the flow time of the solution, m is the flow time of the solvent, and p is the mass of the sample whose viscosity is to be measured.

[0284] Apart from the fact that the measured temperature is 20°C instead of 25°C, the measurement corresponds to the standard ISO 307:2007.

[0285] Measurement of enthalpy of melting

[0286] The enthalpy of fusion was determined by DSC during the second heating run according to standard ISO 11357-3:2013.

[0287] Measurement of crystallization temperature

[0288] Crystallization temperature was determined by differential scanning calorimetry (DSC) according to standard ISO 11357-3:2013 during cooling at a rate of 20°C / min.

[0289] The tested composition also includes the following compounds:

[0290] A phenolic primary antioxidant sold by BASF under the trade name Irganox® 245 (CAS No. 36443-68-2).

[0291] Phosphite secondary antioxidant sold by BASF under the trade name Irgafos® 168 (CAS No. 31570-04-4).

[0292] A dye mixture sold by Avient under the trade name 338160 ORA LLDPE AO Smartbatch, comprising 28% pigment.

[0293] PA 6 homopolymer sold by Domo under the name Domamid H24.

[0294] PA 6.6 homopolymer sold by Radici under the name Radilon A 42K.

[0295] The following compositions were prepared by melt blending various starting materials in a co-rotating twin-screw extruder with a diameter of 26 mm. The products were extruded at a throughput of 16 kg / h, a temperature of 250°C, and a screw speed of 250 rpm. Upon exiting the machine, the products were cooled in a water bath and then granulated. Finally, these products were vacuum dried at 80°C for 8 hours. The formulations of the compositions are shown in Table 2 below, and the contents in the table are expressed as a weight percentage relative to the total weight of the compositions:

[0296]

[0297] Table 2

[0298] Sample preparation

[0299] These compositions were used to injection mold plates (60 × 60 × 1 mm) and ISO 527-1A dumbbells at a temperature of 260°C.

[0300] Measurement of mechanical and chemical properties

[0301] Tensile mechanical properties were measured on dry samples according to standard ISO 527-1:2012. The machine used was an Instron 5966 with a crosshead speed of 50 mm / min.

[0302] De-icing salt resistance was measured on a 1 mm thick plate according to EN 16811-1:2016.

[0303] The results are presented in Table 3.

[0304]

[0305] Table 3

[0306] Measurement of optical and electrical properties:

[0307] Dielectric strength was measured at 25°C on a 1 mm thick plate according to IEC 60243-1:2013.

[0308] The colorimetric properties of the samples were measured in reflectance mode using a Konica Minolta CM-36dGV spectrophotometer in the CIELab system, as defined in standard ISO 11664-4:2008, with a D65 light source, an incident angle of 10°, an aperture of 8 mm, and including the specular component.

[0309] In the L a b In the system, L Indicates brightness, a Indicates the green / red axis, b Indicates the blue / yellow axis. L The higher the value, the lighter the color or the lower the intensity. Conversely, L... The lower the value, the darker or more intense the color. The higher the value, the redder the hue. The higher the value, the more yellow the hue.

[0310] The results are presented in Table 4.

[0311]

[0312] Table 4

[0313] Evaluation of color change

[0314] To conduct aging tests on copper, samples were prepared by compression. A pre-dried 1 mm thick plate was placed on a 3 mm thick copper plate. The assembly was then placed in the center of a 4 mm thick frame and compressed in a press at 220°C. The platen was brought into contact with the sample for 90 seconds without pressure. Next, a pressure of 50 bar was applied for 60 seconds. Finally, the assembly was cooled for 2 minutes while maintaining a pressure of 30 bar.

[0315] The copper structures coated with the composition and the plates made individually with each composition were aged in a ventilated oven at 150°C for 240 h.

[0316] The CIELab system uses a Konica Minolta CM-36dGV spectrophotometer in reflectance mode to measure the colorimetric properties of the surface of aged samples, as defined in standard ISO 11664-4:2008, with a D65 light source, an incident angle of 10°, an aperture of 8 mm, and including the specular component.

[0317] The change in sample color during aging is represented by the parameter ΔE. This is calculated based on the following equation:

[0318]

[0319] In this equation, L a and b This represents the value measured on the aging plate at t=240h, and L0 a0 and b0 This indicates the value measured on an unaged plate. A higher ΔE value indicates a greater color change during aging, suggesting instability of the composition.

[0320] The results of the ΔE values ​​are presented in Table 5.

[0321]

[0322] Table 5

[0323] The results show that the composition according to the present invention has good mechanical, electrical and chemical properties, and exhibits color stability over time.

[0324] After aging at 150°C for 240 h in a ventilated oven, the dielectric strength of each of compositions 1 to 4 remains greater than 10 kV / mm.

[0325] Example 2 – Intermediate Layer of Adhesive Primer

[0326] Preparation of the composition

[0327] Compositions according to the invention were prepared using the compounds of Example 1, and in particular PA 11 A and PA 12 A, to obtain compositions 1 and 2 of Table 2 (Example 1).

[0328] Preparation of coated metal strips

[0329] Use the following adhesive primer: an epoxy acrylate primer sold by Arkema under the trade name Primgreen LAT 12035.

[0330] It is applied by immersing a 3 mm thick copper plate in an adhesive primer composition, followed by crosslinking at 300°C for 10 minutes. The primer layer thickness is 10 μm.

[0331] The structure representing the present invention was prepared by thermal bonding:

[0332] Composition 1 or 2 (1 mm) was applied to a copper plate (3 mm) with or without a primer. The assembly, surrounded by a 4 mm thick frame, was compressed in a press at 220°C. The press plate was placed in contact with the overlay for 90 seconds without pressure. Next, a pressure of 50 bar was applied for 60 seconds. Finally, the assembly was cooled for 2 minutes while maintaining a pressure of 30 bar. A comparative example was prepared in the same manner without an intermediate layer. The structures are shown in Table 6 below:

[0333]

[0334] Table 6

[0335] Structural assessment

[0336] Evaluation of color change

[0337] The copper structure coated with the composition was aged in a ventilated oven at 150°C for 240 h.

[0338] The colorimetric properties of the surface of aged products were measured in reflectance mode using a Konica Minolta CM-36dGV spectrophotometer in the CIELab system, as defined in standard ISO 11664-4:2008, with a D65 light source, an incident angle of 10° and an aperture of 8 mm, and including the specular component.

[0339] Color aging corresponds to the color change between an unaged board (i.e., at t=0) and a board aged at 150°C for t=240 hours. This change is measured by ΔE according to the equation [Mathematical Equation 5] depicted in Example 1.

[0340] A higher ΔE value indicates a greater color change during aging, suggesting instability of the composition. The results are shown in Table 7 below:

[0341]

[0342] Table 7

[0343] Evaluation of salt spray corrosion resistance

[0344] The salt spray resistance of the structure was evaluated according to standard ISO 12944-6:2018. A 50 g / L NaCl solution was sprayed onto the surface of the sample at 35°C for 240 h. The results of this test depend on whether the adhesion at the metal / polymer interface is maintained or whether the interface debonds.

[0345] The results of the evaluation test are given in Table 8 below:

[0346]

[0347] Table 8

[0348] Examples show that the structure according to the present invention has good mechanical properties and exhibits color stability and corrosion resistance over time.

[0349] Example 3 - Metal Interlayer

[0350] Compositions according to the invention were prepared using the compounds of Example 1, and in particular PA 11 A and PA 12 A, to obtain compositions 1 and 2 of Table 2 (Example 1).

[0351] Preparation of coated metal strips

[0352] Use 2 metal plates:

[0353] 3 mm thick pure copper plate

[0354] A 3 mm thick copper plate covered with a 1 μm nickel layer.

[0355] The structure representing the present invention was prepared by thermal bonding:

[0356] Composition A or B (1 mm) / Copper plate with or without nickel coating

[0357] The assembly, surrounded by a 4-mm thick frame, was compressed in a press at 220°C. Without applying pressure, the pressure plate was placed in contact with the overlay for 90 seconds. Next, a pressure of 50 bar was applied for 60 seconds. Finally, the assembly was cooled for 2 minutes while maintaining a pressure of 30 bar.

[0358]

[0359] Table 9

[0360] Evaluation of structure: Evaluation of color change

[0361] The copper structure coated with the composition was aged in a ventilated oven at 150°C for 240 h.

[0362] Colorimetric properties of the surface of aged products were measured in reflectance mode using a Konica Minolta CM-36dGV spectrophotometer in the CIELab system, as defined in standard ISO 11664-4:2008, with a D65 light source, an incident angle of 10°, an aperture of 8 mm, and including the specular component.

[0363] Color aging corresponds to the color change between an unaged board (i.e., at t=0) and a board aged at 150°C for t=240 hours. This change is measured by ΔE according to the equation [Mathematical Equation 5] depicted in Example 1.

[0364] A higher ΔE value indicates a greater color change during aging, suggesting instability of the composition. The results are shown in Table 10 below:

[0365]

[0366] Table 10

[0367] Examples show that the structure according to the present invention has good mechanical properties and exhibits color stability over time.

[0368] Example 4 - Polyolefin Interlayer

[0369] Compositions according to the invention were prepared using the compounds of Example 1, and in particular PA 11 A and PA 12 A, to obtain compositions 1 and 2 of Table 2 (Example 1).

[0370] Preparation of coated metal strips

[0371] Use the following intermediate layer:

[0372] Intermediate layer 1: A 200-μm thick functionalized polyethylene film sold by SK Functional Polymer under the trade name Orevac IM300.

[0373] Intermediate layer 2: A 200-μm thick functionalized polypropylene film sold by SK Functional Polymer under the trade name Orevac CA100.

[0374] The structure representing the present invention was prepared by thermal bonding:

[0375] Composition A or B / Intermediate Layer / Copper

[0376] The assembly, surrounded by a frame of the same thickness as the overall assembly, was compressed in a press at 220°C. Without applying pressure, the pressure plate was placed in contact with the overlay for 90 seconds. Next, a pressure of 50 bar was applied for 60 seconds. Finally, the assembly was cooled for 2 minutes while maintaining a pressure of 30 bar. A comparative example was prepared in the same manner without an intermediate layer.

[0377]

[0378] Table 11

[0379] Evaluation of color change

[0380] The copper structure coated with the composition was aged in a ventilated oven at 150°C for 240 h.

[0381] Colorimetric properties of the surface of aged products were measured in reflectance mode using a Konica Minolta CM-36dGV spectrophotometer in the CIELab system, as defined in standard ISO 11664-4:2008, with a D65 light source, an incident angle of 10°, an aperture of 8 mm, and including the specular component.

[0382] The color change of the sample during aging is represented by the parameter ΔE. This change is measured by ΔE according to the equation [Mathematical Equation 5] described in Example 1.

[0383] The results of the evaluation test are given in Table 12.

[0384]

[0385] Table 12

[0386] Evaluation of adhesion at the metal / polymer interface:

[0387] According to standard NF EN 28510-1:2014, adhesion at the copper / polyolefin interface was measured by peel test using a tensile testing machine. A 7-mm wide polymer strip was cut from an exemplary structure using a punch. One end of the strip was fixed to a movable part of the tensile testing machine while the rest of the sample remained horizontal. Peeling was performed by moving the movable part of the tensile testing machine up and down at a speed of 50 mm / min. A force sensor recorded the adhesive strength resisting this peel.

[0388] The results of the evaluation test are given in Table 13.

[0389]

[0390] Table 13

[0391] Examples show that the structure according to the present invention has good mechanical properties and exhibits color stability and good coating adhesion over time.

Claims

1. An electrical insulation composition for covering power transmission components, comprising: - Primarily at least one polyamide, the polyamide having: - The absolute value difference between the total acidity and total basicity of the polyamide, less than 70, wherein the total basicity and total acidity are measured by potentiometry. - Total alkalinity less than 60 μeq / g, measured by potentiometry, and The composition primarily comprises at least one polyamide having a carbon number greater than 6.5 per nitrogen atom, and - at least one colorant Its features The color of the composition is different from black.

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

3. The composition claimed in claim 1 or 2, characterized in that, The at least one polyamide is an aliphatic or alicyclic polyamide.

4. The composition claimed in any one of the preceding claims, characterized in that, The polyamide has an intrinsic viscosity greater than 1.1 as measured according to standard ISO 307:2007.

5. The composition according to any one of claims 1 to 3, characterized in that, The polyamide has a melting enthalpy greater than 20 J / g, as measured by DSC during the second heating according to standard ISO 11357-3:2013.

6. The composition according to any one of the preceding claims, characterized in that the polyamide has a crystallization temperature strictly below 180°C as measured by DSC during the second heating run according to standard ISO 11357-3:2013.

7. The composition according to any one of the preceding claims, characterized in that, The total acidity of the polyamide is less than 60 μeq / g.

8. The composition according to any one of the preceding claims, characterized in that... The primary polyamide is selected from PA 11, PA 12, PA 1010, PA 1012, PA 610, PA 612, PA 516, PA 613, PA 912, PA 6 / 11, PA 6 / 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, more particularly PA 11, PA 12, PA 1010, PA 1012, even more preferably PA 11 or PA 12, with PA 11 being the most preferred.

9. The composition according to any one of the preceding claims, characterized in that, The colorant is a mixture of at least two pigments.

10. The composition according to any one of the preceding claims, characterized in that, The colorant comprises titanium dioxide, tin oxide, zinc oxide, and mixtures thereof.

11. The composition according to the preceding claims, characterized in that, The colorant comprises titanium dioxide, tin oxide, zinc oxide, and at least two other pigments.

12. The composition according to any one of the preceding claims, characterized in that, The colorant content ranges from 0.5% to 10% by weight, preferably from 1% to 5% by weight, relative to the total weight of the composition.

13. The composition according to any one of the preceding claims, characterized in that, The composition contains at least one antioxidant.

14. Use of the composition as defined in claims 1 to 13 for covering power transmission components, preferably battery busbars.

15. A power transmission component, comprising: - Power transmission components with metallic surfaces, and - A coating made from a composition as defined in any one of claims 1 to 13.

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

17. The component according to claim 15 or 16, characterized in that, The component is a busbar.

18. A method for preparing a power transmission component, comprising the step of covering a metal surface of the power transmission component with a composition as defined in any one of claims 1 to 13.

19. The method according to the preceding claim, characterized in that, It includes steps of pretreating the metal surface by degreasing and / or flame treatment and / or preheating.

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