Molded article for wireless power supply

Abstract

The present invention provides a thermoplastic resin composition molded article which exhibits excellent potting performance, heat resistance, and product assemblability in spite of being a large-sized molded article, and which is suitable for wireless power supply applications.　This molded article for wireless power supply is obtained by molding a thermoplastic resin composition that exhibits a breakdown voltage of 10 kV / mm or higher according to IEC60243, belongs to PLC class IIIC or higher in tracking resistance evaluation according to IEC60112, and has a deflection temperature of 150°C or higher under a load of 1.8 MPa. The molded article has dimensions of 400-1000 mm in width, 400-2000 mm in length, and 2-20 mm in thickness, and has a flatness of 15 mm or less.

Description

Molded product for wireless power supply

[0001] The present invention relates to a large-sized thermoplastic resin molded product for wireless power supply, which is excellent in product assembly property, heat resistance, and potting property despite being a large-sized molded product.

[0002] In recent years, regarding global warming and energy issues, various efforts have been made from the perspective of low environmental impact. Among them, in order to reduce the emissions of carbon dioxide and nitrogen oxides during driving, as next-generation automobiles, electric vehicles, fuel cell vehicles, hybrid vehicles, etc. that use an electric motor in the drive mechanism have attracted attention.

[0003] For electric vehicles to further spread in the future, it is essential to extend the cruising range. As a method to extend the cruising range, while the enlargement and high capacity of the battery are being considered, the utilization of a non-contact power supply system is also being considered. The in-vehicle non-contact power supply system consists of a large-sized power transmission coil device installed on the ground or underground, etc., and a large-sized power reception coil device connected to the in-vehicle battery, and uses magnetic coupling between coils such as the electromagnetic induction method or the magnetic field resonance method to enable non-contact power transmission.

[0004] For the practical application of the in-vehicle non-contact power supply system, it is necessary to increase the transmitted power and improve the power supply efficiency. For example, Patent Document 1 describes an in-vehicle non-contact power supply system that realizes efficient power supply, and Patent Document 2 describes a coil device that enables adjustment of the inductance value of the coil from the perspective of improving the efficiency of transmitted power.

[0005] International Publication WO2010 / 035321, International Publication WO2018 / 043590

[0006] On the other hand, in the in-vehicle non-contact power supply system, with the increase in the transmitted power and the improvement of the power supply efficiency, the heat generation amount of the entire system has increased centering around the coil device. Therefore, as components constituting the system, high insulation and high heat resistance are required for resin molded products used for covers and coil holding members. Also, since the coil device is a large-sized component and the product will be damaged during assembly to an automobile if it is distorted, high dimensional accuracy is required for the resin molded product.

[0007] However, while the devices and systems disclosed in Patent Documents 1 and 2 achieve increased power transmission and improved power supply efficiency, they do not disclose resin molded products used for covers and coil holding members, which are essential for coil devices. In other words, despite being large molded products, thermoplastic resin molded products that offer excellent product assembly, heat resistance, and potting properties, and are suitable for wireless power supply applications, have not yet been considered.

[0008] The inventors of the present invention have conducted extensive research to solve the above problems and have found that a molded article made of thermoplastic resin having the following characteristics is suitable for wireless power supply components. That is, the present invention has the following configuration: (1) A molded article for wireless power supply made by molding a thermoplastic resin composition having a dielectric breakdown voltage of 10 kV / mm or more in accordance with IEC 60243, PLC class IIIIC or higher in tracking resistance evaluation in accordance with IEC 60112, and a load deflection temperature of 150°C or higher at 1.8 MPa, wherein the dimensions are 400 mm to 1000 mm in width x 400 mm to 2000 mm in length x 2 mm to 20 mm in thickness, and the flatness is 15 mm or less. (2) The molded article for wireless power supply according to (1), wherein the thermoplastic resin composition contains a fibrous filler. (3) The molded article for wireless power supply according to (1) or (2), wherein the thermoplastic resin composition is V-0 at a thickness of 1.5 mm or more in flammability evaluation in accordance with UL94. (4) A molded article for wireless power transfer according to (1) or (2), wherein the coefficient of linear expansion of the thermoplastic resin composition at -40°C to 150°C is 100 ppm / K or less. (5) A molded article for wireless power transfer according to (1) or (2), wherein the tensile modulus of the thermoplastic resin composition is 10 GPa or more. (6) A molded article for wireless power transfer according to (1) or (2), wherein the thermoplastic resin composition is a resin composition consisting of a polyarylene sulfide resin, an aromatic polyamide resin, or a polyphenylene ether resin.

[0009] According to the present invention, it is possible to provide a thermoplastic resin molded product that is suitable for wireless power supply applications, as it exhibits excellent product assembly, heat resistance, and potting properties despite being a large molded product.

[0010] This is a schematic diagram of the molded product used for evaluation.

[0011] The present invention relates to a molded article made by molding a thermoplastic resin composition having a dielectric breakdown voltage of 10 kV / mm or more according to IEC 60243, PLC class IIIIC or higher in tracking resistance evaluation according to IEC 60112, and a load deflection temperature of 150°C or higher at 1.8 MPa, with dimensions of 400 mm to 1000 mm in width, 400 mm to 2000 mm in length, and 2 mm to 20 mm in thickness, and a flatness of 15 mm or less. Despite being a large molded article, it exhibits excellent product assembly, heat resistance, and potting properties, and it has been found that such a thermoplastic resin composition molded article can be applied to a new application called wireless power transfer.

[0012] Embodiments of the present invention will be described below.

[0013] (A) Thermoplastic resin The thermoplastic resin used in the thermoplastic resin composition constituting the molded article for wireless power supply of the present invention is not particularly limited in type, and examples include polyamide resin, polyester resin, fluororesin, polyoxymethylene, olefin resin, polyacrylate, polyphenylene ether, polycarbonate, polyethersulfone, polyetherimide, polyetherketone, polyetheretherketone, polyarylene sulfide, cellulose derivative, liquid crystalline resin, and modified resins thereof. Two or more of these may be included.

[0014] Specific examples of polyamide resins include, for example, polycaproamide (nylon 6), polyhexamethylene adipamide (nylon 66), polypentamethylene adipamide (nylon 56), polytetramethylene adipamide (nylon 46), polyhexamethylene sevacamide (nylon 610), polyhexamethylene dodecamide (nylon 612), polyundecaneamide (nylon 11), polydodecaneamide (nylon 12), polycaproamide / polyhexamethylene adipamide copolymer (nylon 6 / 66), polycaproamide / polyhexamethylene terephthalamide copolymer (nylon 6 / 6T), polyhexamethylene adipamide / polyhexamethylene isophthalamide copolymer Examples include polymers (nylon 66 / 6I), polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (nylon 6T / 6I), polyhexamethylene terephthalamide / polydodecaneamide copolymer (nylon 6T / 12), polyhexamethylene adipamide / polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (nylon 66 / 6T / 6I), polyxylylene adipamide (nylon XD6), polyhexamethylene terephthalamide / poly-2-methylpentamethylene terephthalamide copolymer (nylon 6T / M5T), polynonamethylene terephthalamide (nylon 9T), and copolymers thereof. Two or more of these may be blended. Among these, semi-aromatic nylons such as polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (nylon 6T / 6I), polycaproamide / polyhexamethylene terephthalamide copolymer (nylon 6 / 6T), polyxylylene adipamide (nylon XD6), polyhexamethylene terephthalamide / poly-2-methylpentamethylene terephthalamide copolymer (nylon 6T / M5T), and polynonamethylene terephthalamide (nylon 9T) are preferred from the viewpoint of heat resistance.

[0015] As polyesters, polymers or copolymers having residues of dicarboxylic acid or its ester-forming derivative and diol or its ester-forming derivative as the main structural units are preferred. Among these, aromatic polyesters such as polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polycyclohexanedimethylene terephthalate, polyethylene naphthalate, polypropylene naphthalate, polybutylene naphthalate, polyethylene isophthalate / terephthalate, polypropylene isophthalate / terephthalate, polybutylene isophthalate / terephthalate, polyethylene terephthalate / naphthalate, polypropylene terephthalate / naphthalate, and polybutylene terephthalate / naphthalate are particularly preferred, with polybutylene terephthalate being the most preferred. Two or more of these may be contained. In these polyesters, the ratio of terephthalic acid residues to total dicarboxylic acid residues is preferably 30 mol% or more, and more preferably 40 mol% or more.

[0016] Polycarbonates can be obtained by methods such as the phosgene process, in which phosgene is blown into a difunctional phenolic compound in the presence of a caustic alkali and a solvent, and the transesterification process, in which a difunctional phenolic compound is transesterified with diethyl carbonate in the presence of a catalyst. Examples of polycarbonates include aromatic homopolycarbonates and aromatic copolymers.

[0017] Examples of olefin resins include polypropylene, polyethylene, ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene / propylene / non-conjugated diene copolymer, ethylene / ethyl acrylate copolymer, ethylene / glycidyl methacrylate copolymer, ethylene / vinyl acetate / glycidyl methacrylate copolymer, propylene-g-maleic anhydride copolymer, ethylene / propylene-g-maleic anhydride copolymer, and methacrylic acid / methyl methacrylate / glutaric anhydride copolymer. Two or more of these may be included.

[0018] Examples of polyarylene sulfides include polyphenylene sulfide (PPS), polyphenylene sulfide sulfone, polyphenylene sulfide ketone, random copolymers thereof, and block copolymers. Two or more of these may be used.

[0019] Polyarylene sulfides can be produced by commonly known methods, such as the method for obtaining relatively small molecular weight polymers described in Japanese Patent Publication No. 45-3368, and the methods for obtaining relatively large molecular weight polymers described in Japanese Patent Publication No. 52-12240 and Japanese Unexamined Patent Publication No. 61-7332. The obtained polyarylene sulfides can, of course, also be used after undergoing various treatments, such as crosslinking / increasing molecular weight by heating, heat treatment under an inert gas atmosphere such as nitrogen or under reduced pressure, washing with organic solvents, hot water, or acidic aqueous solutions, and activation with functional group-containing compounds such as acid anhydrides, amines, isocyanates, and functional group-containing disulfide compounds.

[0020] Examples of polyphenylene ether resins include poly(2,6-dimethyl-1,4-phenylene) ether, poly(2,6-diethyl-1,4-phenylene) ether, poly(2,6-dipropyl-1,4-phenylene) ether, poly(2-methyl-6-ethyl-1,4-phenylene) ether, poly(2-methyl-6-propyl-1,4-phenylene) ether, and poly(2,6-dichloro-1,4-phenylene ether). Furthermore, copolymers of 2,6-dimethylphenol with other phenols (for example, copolymers with 2,3,6-trimethylphenol and copolymers with 2-methyl-6-butylphenol as described in Japanese Patent Publication No. 52-17880) are also examples.

[0021] Examples of cellulose derivatives include cellulose acetate, cellulose acetate butyrate, and ethylcellulose. Two or more of these may be included.

[0022] Among these thermoplastic resins, polyarylene sulfide resin, semi-aromatic polyamide resin, or polyphenylene ether is preferred from the viewpoint of heat resistance.

[0023] (B) Fibrous filler The thermoplastic resin composition constituting the molded article for wireless power supply of the present invention preferably contains (B) fibrous filler. By incorporating (B) fibrous filler, the flatness of the molded article can be improved, as well as the heat resistance and rigidity can be improved, making it more suitable for use as a wireless power supply component. Examples of (B) fibrous filler include glass fiber, glass milled fiber, carbon fiber, irregular cross-section glass fiber, glass cut fiber, stainless steel fiber, metal fibers such as aluminum fiber and brass fiber, organic fibers such as Kevlar® fibril, gypsum fiber, ceramic fiber, asbestos fiber, zirconia fiber, alumina fiber, titanium oxide fiber, silicon carbide fiber, carbon nanotube, and cellulose nanofiber.

[0024] (B) Among fibrous fillers, it is preferable to use at least one selected from glass fibers and irregularly shaped cross-section glass fibers from the viewpoint of availability and mechanical strength. Among these, irregularly shaped cross-section glass fibers are most preferred because they can reduce the MD / TD ratio, which is the ratio of the coefficient of linear expansion (MD) in the flow direction of the resin to the tensile strength (TD) perpendicular to the flow direction of the resin in the molded product, thereby suppressing cracking during epoxy potting. Irregularly shaped cross-section glass fibers are glass fibers having a flattened cross-section, and it is preferable that the ratio of the major axis (longest straight distance of the cross-section) to the minor axis (longest straight distance perpendicular to the major axis) (major axis / minor axis, hereinafter sometimes abbreviated as flatness ratio) in the cross-section when the glass fiber is cut perpendicular to the length direction is 1.3 or more and 10 or less. Preferably it is 1.5 or more and 7 or less, and more preferably 1.5 or more and 5 or less. If the flatness ratio is 1.3 or more, the resin composition has good resistance to cold and thermal shock, and if it is 10 or less, the resin composition has good mechanical strength. The flattening ratio was determined by observing the cross-sections of 50 randomly selected glass fibers using a scanning electron microscope, measuring their major and minor axes, calculating their ratio, and then calculating the number average.

[0025] The fibrous filler (B) used in the present invention is preferably treated with a consolidating agent or a surface treatment agent. Examples of consolidating agents or surface treatment agents include functional compounds such as epoxy compounds, isocyanate compounds, silane compounds, and titanate compounds, with epoxy compounds having a high epoxy content being particularly preferred from the viewpoint of improving the reactivity of the fibrous filler and suppressing the decrease in strength due to immersion treatment in a cooling medium.

[0026] In the present invention, the lower limit of the amount of (B) fibrous filler is preferably 40 parts by mass or more, and more preferably 60 parts by mass or more, per 100 parts by mass of (A) thermoplastic resin, from the viewpoint of mechanical strength and heat resistance. The upper limit is preferably 150 parts by mass or less, and more preferably 130 parts by mass or less, per 100 parts by mass of (A) thermoplastic resin, from the viewpoint of fluidity.

[0027] (C) Non-fibrous filler The thermoplastic resin composition constituting the molded article for wireless power supply of the present invention preferably contains (C) a non-fibrous filler. Examples of (C) non-fibrous fillers include fullerene, talc, warlastenite, zeolite, sericite, mica, kaolin, clay, pyrophyllite, bentonite, asbestos, silicates such as alumina silicate, metal compounds such as silicon oxide, magnesium oxide, alumina, zirconium oxide, titanium oxide, and iron oxide, carbonates such as calcium carbonate, magnesium carbonate, and dolomite, sulfates such as calcium sulfate and barium sulfate, glass beads, glass flakes, glass powder, ceramic beads, boron nitride, silicon carbide, carbon black, silica, and graphite. These may be hollow, and it is also possible to use two or more of these non-fibrous fillers in combination. Furthermore, these non-fibrous fillers may be pre-treated with coupling agents such as isocyanate compounds, organosilane compounds, organotitanate compounds, organoborane compounds, and epoxy compounds before use.

[0028] In particular, calcium carbonate and glass flakes are preferred from the viewpoint of mechanical strength and low warping.

[0029] The lower limit of the amount of (C) non-fibrous filler used in the present invention is preferably 30 parts by mass or more, and more preferably 50 parts by mass or more, per 100 parts by mass of (A) thermoplastic resin, from the viewpoint of flame retardancy and tracking resistance. The upper limit is preferably 140 parts by mass or less, and more preferably 110 parts by mass or less, per 100 parts by mass of (A) thermoplastic resin, from the viewpoint of mechanical strength.

[0030] Furthermore, the thermoplastic resin composition constituting the molded article for wireless power transfer of the present invention may optionally contain silane compounds to improve mechanical strength, toughness, etc., as long as it does not impair the effects of the present invention. Examples of silane compounds include isocyanate group-containing alkoxysilane compounds such as γ-isocyanatetopropyltriethoxysilane, γ-isocyanatetopropyltrimethoxysilane, γ-isocyanatetopropylmethyldimethoxysilane, γ-isocyanatetopropylmethyldiethoxysilane, γ-isocyanatetopropylethyldimethoxysilane, γ-isocyanatetopropylethyldiethoxysilane, and γ-isocyanatetopropyltrichlorosilane; epoxy group-containing alkoxysilane compounds such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; amino group-containing alkoxysilane compounds such as γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, and γ-aminopropyltrimethoxysilane; and silane compounds such as modified silicone oils having epoxy groups, amino groups, isocyanate groups, and hydroxyl groups. Among these, alkoxysilanes having epoxy groups, amino groups, isocyanate groups, and hydroxyl groups are particularly suitable for obtaining excellent mechanical strength and thermal shock resistance. The preferred amount of such silane compound to be added is selected to be in the range of 0.05 to 3 parts by mass per 100 parts by mass of (A) thermoplastic resin.

[0031] Furthermore, the thermoplastic resin composition constituting the molded article for wireless power supply of the present invention preferably contains one or more antioxidants selected from phenolic compounds and phosphorus compounds in order to maintain high heat resistance and thermal stability without impairing the effects of the present invention. From the viewpoint of improving heat resistance, the amount of such antioxidant is preferably 0.01 parts by mass or more, particularly 0.02 parts by mass or more, per 100 parts by mass of (A) thermoplastic resin, and from the viewpoint of reducing gas components generated during molding, it is preferably 5 parts by mass or less, particularly 1 part by mass or less. In addition, using phenolic antioxidants and phosphorus antioxidants in combination is particularly preferable as it greatly enhances the effect of maintaining heat resistance and thermal stability.

[0032] The thermoplastic resin composition of the present invention may optionally contain (D) a flame retardant. By adding (D) a flame retardant, flame retardancy can be imparted to resins that do not inherently possess flame retardancy, making it more suitable for use in in-vehicle wireless power supply systems. (D) The flame retardant is not particularly limited as long as it is a substance added for the purpose of imparting flame retardancy to the resin, and examples include halogen-based flame retardants and non-halogen-based flame retardants. Specifically, decabromodiphenyl oxide, octabromodiphenyl oxide, tetrabromodiphenyl oxide, tetrabromophthalic anhydride, hexabromocyclododecane, bis(2,4,6-tribromophenoxy)ethane, ethylenebistetrabromophthalimide, hexabromobenzene, 1,1-sulfonyl[3,5-dibromo-4-(2,3-dibromopropoxy)]benzene, polydibromophenylene oxide, tetrabromobisphenol-S, tris(2,3-dibromopropyl-1) isocyanurate, tribromophenol, tribromophenylallyl ether, tribromoneopentyl alcohol, brominated polystyrene, brominated polyethylene, tetrabromobisphenol-A, tetrabromobisphenol-A derivatives, tetrabromobisphenol-A epoxy Examples include oligomers or polymers, tetrabromobisphenol-A-carbonate oligomers or polymers, brominated epoxy resins such as brominated phenol novolac epoxy, tetrabromobisphenol-A-bis(2-hydroxydiethyl ether), tetrabromobisphenol-A-bis(2,3-dibromopropyl ether), tetrabromobisphenol-A-bis(allyl ether), tetrabromocyclooctane, ethylenebispentabromodiphenyl, tris(tribromoneopentyl) phosphate, polypentabromobenzyl acrylate, octabromotrimethylphenylindan, dibromoneopentyl glycol, pentabromobenzyl polyacrylate, dibromocrezyl glycidyl ether, and N,N'-ethylene-bis-tetrabromophthalimide. (D) The amount of flame retardant is preferably in the range of 1 to 50 parts by mass per 100 parts by mass of the thermoplastic resin (A).If the amount added is less than 1 part by mass, the effect of improving the flame retardancy of the thermoplastic resin (A) may not be obtained. From the viewpoint of obtaining stable flame retardancy, 10 parts by mass or more is preferred. If the amount added exceeds 50 parts by mass, the strength of the thermoplastic resin composition may decrease. 40 parts by mass or less is preferred.

[0033] The thermoplastic resin composition of the present invention may optionally contain (E) a flame retardant additive. By using it in combination with (D) a flame retardant, flammability can be improved. Examples of (E) flame retardant additives include antimony compounds, such as antimony trioxide, antimony tetroxide, antimony pentoxide, antimony halides, and sodium antimonate, but antimony trioxide is preferred from the viewpoint of availability. The amount of (E) flame retardant additive added is preferably 1 to 25 parts by mass per 100 parts by mass of the (A) thermoplastic resin. If the amount added is less than 1 part by mass, flame retardancy of the thermoplastic resin composition may not be obtained. 10 parts by mass or more is preferred. If the amount added exceeds 25 parts by mass, the strength of the thermoplastic resin composition may decrease.

[0034] There are no particular limitations on the method for preparing the thermoplastic resin composition of the present invention, but typical examples include supplying each raw material to a commonly known melt mixer such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, and a mixing roll, and kneading them at a temperature of 280 to 380°C. There are no particular limitations on the mixing order of the raw materials, and any of the following methods may be used: a method in which all raw materials are blended and then melt-kneaded by the above method; a method in which some raw materials are blended and then melt-kneaded by the above method, and then the remaining raw materials are blended and melt-kneaded again; or a method in which some raw materials are blended and then the remaining raw materials are mixed using a side feeder while melt-kneading is performed with a single-screw or twin-screw extruder. Furthermore, for small amounts of additive components, it is also possible to knead other components by the above method or other methods to form pellets, and then add them before molding.

[0035] The thermoplastic resin composition used in the present invention, obtained in this manner, can be subjected to various molding processes such as injection molding, extrusion molding, blow molding, and transfer molding, as well as machining after initial molding. However, from the viewpoint of productivity, it is particularly suitable for injection molding.

[0036] The tensile modulus of the thermoplastic resin composition constituting the molded article for wireless power transfer of the present invention, as measured in accordance with ISO 527-1, -2 (2012), is preferably 10 GPa or higher, and more preferably 12 GPa or higher. This makes it possible to suppress cracking caused by differences in shrinkage rates after epoxy potting in large molded articles used for wireless power transfer. There is no particular upper limit to the tensile modulus, but it is preferably 21 GPa or lower, and more preferably 20 GPa or lower. If it exceeds 21 GPa, the toughness decreases, and cracking may occur when assembling the thermoplastic resin composition molded article.

[0037] To achieve a tensile modulus of 10 GPa or more in a molded article of the thermoplastic resin composition of the present invention, it is possible to (A) use a highly crystalline thermoplastic resin, and to incorporate (B) a fibrous filler and (C) a non-fibrous filler that have a high effect in increasing rigidity.

[0038] The molded article for wireless power supply of the present invention has dimensions of 400 mm to 1000 mm in width, 400 mm to 2000 mm in length, and 2 mm to 20 mm in thickness, with a flatness of 15 mm or less.

[0039] Flatness refers to the degree of deviation of a planar shape from a geometrically correct plane. It is the value of the gap created when the target plane is sandwiched between parallel planes, and a smaller value indicates less warping of the molded product. The molded product for wireless power supply in this invention is large in size, with a width of 400 mm to 1000 mm, a length of 400 mm to 2000 mm, and a thickness of 2 mm to 20 mm. If the flatness is greater than 15 mm, the molded product will be subjected to stress when assembled, causing cracks. Furthermore, in order to suppress misalignment between the power supply unit and the power receiving unit system, a flatness of 10 mm or less is preferable, and 7 mm or less is even more preferable. The flatness of the molded product for wireless power supply can be measured using a three-dimensional dimensional measuring instrument.

[0040] The thermoplastic resin composition constituting the molded article for wireless power transfer of the present invention has a load deflection temperature of 150°C or higher at 1.8 MPa in accordance with ISO 75-1. If it is below 150°C, the wireless power transfer system may be damaged because it will deform due to molten asphalt when laid underground. To make the load deflection temperature of the thermoplastic resin composition molded article of the present invention 150°C or higher at 1.8 MPa, it is possible to (A) use a thermoplastic resin with a high glass transition temperature, and to blend in (B) a fibrous filler and (C) a non-fibrous filler that have a high effect in increasing rigidity.

[0041] The thermoplastic resin composition constituting the molded article for wireless power transfer of the present invention preferably has a coefficient of linear expansion of 100 ppm / K or less in the range of -40 to 150°C. This minimizes thermal changes even when the coil generates heat during wireless power transfer, and the positional misalignment between the power supply unit and the power receiving unit remains unchanged, thus enabling efficient wireless power transfer. Furthermore, the coefficient of linear expansion is measured in the range of -40 to 150°C in accordance with ISO 11359-2 (2021), and the specific measurement method is described in the Examples section.

[0042] To make the coefficient of linear expansion 100 ppm / K or less in the range of -40 to 150°C, this can be achieved by (A) using a thermoplastic resin with a high glass transition temperature, and (B) using fibrous filler in an amount of 40 parts by mass or more per 100 parts by mass of the thermoplastic resin (A).

[0043] The thermoplastic resin composition constituting the molded article for wireless power feeding of the present invention preferably has a flame retardancy measured in accordance with UL94 of V-0 when the test piece thickness is 1.5 mmt or more. Thereby, the molded article of the present invention can also be applied to wireless power feeding parts that require flame retardancy. Since it can also cope with thin-walled parts for the purpose of weight reduction, it is more preferable that the flame retardancy exhibits V-0 when the test piece thickness is 0.75 mmt or more. In order to exhibit V-0 in terms of flame retardancy when the test piece thickness is 1.5 mmt or more, it is necessary to use a highly flame-retardant thermoplastic resin such as PPS resin, reduce the blending amount of the resin which is a non-combustible component of flame retardancy, increase the content of (B) fibrous filler and (C) non-fibrous inorganic filler, increase the blending amount of (C) non-fibrous filler, or blend (D) flame retardant and (E) flame retardant aid.

[0044] The thermoplastic resin composition constituting the molded article for wireless power feeding of the present invention has a tracking resistance, that is, a tracking resistance measured in accordance with IEC60112 (2003) of PLC class IIIC or higher. If the tracking resistance is PLC class IIIC or higher, it can be suitably used at a location with a pollution degree of 2 in the product use environment in a high voltage range of about 160V to 600V, which is the rated voltage applied when used in in-vehicle wireless power feeding parts. In order to exhibit a tracking resistance of PLC class IIIC or higher, in addition to using a resin with inherently high tracking resistance, it is possible by reducing the blending amount of the resin and blending a large amount of (B) fibrous filler and (C) non-fibrous inorganic filler.

[0045] The molded article for wireless power feeding of the present invention is excellent in product assembly property, heat resistance, and potting property despite being a large molded article, and thus is suitable for a wireless power feeding system. Examples of the wireless power feeding system can include a cover, a coil holding member, a bus bar, a current sensor, a cooling unit, a bus bar, a connector, etc. for various applications.

[0046] Examples are shown below to more specifically explain the present invention, but the present invention is not limited to the descriptions of these examples.

[0047] [Reference Example 1] Preparation of (A-1) PPS-1 An agitator and a 70-liter autoclave with a bottom plug valve were charged with 8.27 kg (70.00 mol) of 47.5% sodium hydrosulfide, 2.94 kg (70.63 mol) of 96% sodium hydroxide, 11.45 kg (115.50 mol) of N-methyl-2-pyrrolidone (NMP), 1.89 kg (23.1 mol) of sodium acetate, and 5.50 kg of ion-exchanged water. While passing nitrogen at normal pressure, it was gradually heated to 245 °C over about 3 hours. After 9.77 kg of water and 0.28 kg of NMP were distilled off, the reaction vessel was cooled to 200 °C. Then, 10.42 kg (70.86 mol) of p-dichlorobenzene and 9.37 kg (94.50 mol) of NMP were added. The reaction vessel was sealed under nitrogen gas and heated from 200 °C to 270 °C at a rate of 0.6 °C / min while stirring at 240 rpm, and reacted at 270 °C for 140 minutes. Then, while cooling from 270 °C to 250 °C over 15 minutes, 2.40 kg (133 mol) of water was press-fitted. Next, after gradually cooling from 250 °C to 220 °C over 75 minutes, it was rapidly cooled to near room temperature and the content was taken out. The content was diluted with about 35 liters of NMP to form a slurry, stirred at 85 °C for 30 minutes, and then filtered through an 80-mesh wire mesh (opening size 0.175 mm) to obtain a solid. The obtained solid was similarly washed and filtered with about 35 liters of NMP. The operation of diluting the obtained solid with 70 liters of ion-exchanged water, stirring at 70 °C for 30 minutes, and then filtering through an 80-mesh wire mesh to recover the solid was repeated a total of 3 times. The obtained solid and 32 g of acetic acid were diluted with 70 liters of ion-exchanged water, stirred at 70 °C for 30 minutes, filtered through an 80-mesh wire mesh, and further the obtained solid was diluted with 70 liters of ion-exchanged water, stirred at 70 °C for 30 minutes, and filtered through an 80-mesh wire mesh to recover the solid. The solid thus obtained was dried at 120 °C under a nitrogen stream to obtain PPS-1. The melting point of PPS-1 was 280 °C.

[0048] [Reference Example 2] (A-2) In a 50-liter autoclave equipped with a PA6T / M5T-1 preparation stirrer and bottom valve, 6.97 kg (60.0 mol) of 1,6-hexanediamine, 4.64 kg (40.0 mol) of 2-methyl-1,5-pentanediamine, 18.2 kg (100.0 mol) of terephthalic acid, and 24.8 g (0.23 mol) of sodium hypophosphite were charged. After purging with nitrogen, the mixture was reacted at 250°C and 0.35 MPa for 1 hour. After 1 hour, the reaction product generated in the reactor was transferred to a separate container connected to the reactor with a pressure of approximately 1.0 kg / cm². ２ The mixture was extracted into a receiver set to a low temperature to obtain a prepolymer. The obtained prepolymer was then dried and melt-polymerized using a twin-screw extruder at a cylinder temperature of 330°C to obtain PA6T / M5T-1, a semi-aromatic polyamide resin. The melting point of PA6T / M5T-1 was 318°C.

[0049] [Reference Example 3] (A-3) Preparation of ABS-1 700 g (on a solids basis) of polybutadiene latex (average rubber particle size 0.3 μm, gel content 85%), 2000 g of pure water, 4 g of sodium formaldehyde sulfoxylate, 1 g of sodium ethylenediaminetetraacetate, 0.1 g of ferrous sulfate, and 1 g of sodium phosphate were charged into a reaction vessel. After purging with nitrogen, the temperature was maintained at 65°C, and under stirring, a mixture of 228 g of styrene, 72 g of acrylonitrile, and 0.3 parts of n-dodecyl mercaptan was continuously added dropwise over 4 hours. Simultaneously, a mixture of 0.25 parts of cumene hydroperoxide, 25 g of sodium laurate (an emulsifier), and 25 g of pure water was continuously added dropwise over 5 hours. After the addition was complete, the mixture was held for another hour to complete the polymerization and obtain latex. 250 g of styrene was added to 5 parts of the solids of this latex and stirred well, and then 3 g of magnesium sulfate was added. The mixture was separated into a white polymer / monomer phase (cram), and 472 g of styrene, 230 g of acrylonitrile, 1.5 g of n-dodecyl mercaptan, and 0.3 parts of cumene hydroperoxide were added to create a homogeneous solution (raw material dope). Next, this raw material dope was continuously charged into a polymerization tank having a helical ribbon-type stirring blade, with a condenser and a static separator directly connected to the top. The jacket was designed so that water was removed from the lower phase of the separator and only monomer was extracted from the upper phase and refluxed back into the polymerization tank. The polymer concentration was controlled to 75%. A polymerization reaction mixture with a polymer concentration of 75% was continuously supplied to a preheater, a demonomerizer, a twin-screw extruder-type feeder having a heating device tandem-connected to a barrel section 1 / 3 of the way from the tip of the demonomerizer, and a twin-screw extruder having a vent hole. At 200°C, the remaining monomer was recovered by vacuum evaporation through the vent hole. 5 g of t-butylhydroxytoluene, a phenolic stabilizer, and 5 g of tri(nonylphenyl)phosphite, a phosphorus-based stabilizer, were supplied from the twin-screw extruder-type feeder to obtain ABS-1. The glass transition temperature of ABS-1 was 87°C.

[0050] (A) Thermoplastic resin A-1 PPS-1 prepared in Reference Example 1 A-2 PA6T / M5T-1 prepared in Reference Example 2 A-3 ABS-1 prepared in Reference Example 3.

[0051] (B) Fibrous filler B-1 Circular cross-section glass fiber (T-760H manufactured by Nippon Electric Glass Co., Ltd., aspect ratio 1) B-2 Irregular cross-section glass fiber (T-760FGF manufactured by Nippon Electric Glass Co., Ltd., aspect ratio 4).

[0052] (C) Non-fibrous filler C-1 Heavy calcium carbonate (Escalon #800 manufactured by Sankyo Flour Milling Co., Ltd.) C-2 Magnesium hydroxide (KISUMA5EU manufactured by Kyowa Chemical Industry Co., Ltd.).

[0053] (D) Flame retardant D-1 Brominated polystyrene (SAYTEX HP-7010 manufactured by Albemarle Co., Ltd.).

[0054] (E) Flame retardant additive E-1 Antimony trioxide (PATOX-MK manufactured by Nippon Seikou Co., Ltd.).

[0055] [Method for measuring and evaluating molded articles made of resin composition] The measurement and evaluation methods in this example and comparative example are as follows.

[0056] (1) Tensile modulus resin composition pellets were supplied to an injection molding machine (SE-50D) manufactured by Sumitomo Heavy Industries, Ltd., with the cylinder temperature set to the melting point of thermoplastic resin (A) + 30°C and the mold temperature to 80°C or 145°C. Using a mold of type A1 test specimen shape as specified in ISO 20753 (2008), injection molding was performed under the conditions of a filling time of 0.8 s and a holding pressure of 75% of the filling pressure to obtain evaluation test specimens. These test specimens were conditioned for 16 hours at 23°C and 50% relative humidity, and then the tensile modulus was measured in accordance with ISO 527-1, -2 (2012) under the conditions of a grip distance of 115 mm and a test speed of 5 mm / min in an atmosphere of 23°C and 50% relative humidity.

[0057] (2) Load deflection temperature Similar to (1), evaluation specimens were obtained by injection molding using a mold of type A1 test specimen shape specified in ISO 20753 (2008). The load deflection temperature was measured using the flatwise A method (1.80 MPa load) in accordance with ISO 75-1 using an HDT tester 6M-2 manufactured by Toyo Seiki Co., Ltd.

[0058] (3) Tracking-resistant resin composition pellets were supplied to a Sumitomo Heavy Industries, Ltd. injection molding machine (SE50DUZ-C160) set to a cylinder temperature of the melting point of the thermoplastic resin + 30°C and a mold temperature of 130°C. Using a mold for a rectangular plate (80 mm × 80 mm × 3.0 mm thick), injection molding was performed under conditions of a filling time of 0.5 s and a holding pressure of 50% of the filling pressure to obtain a rectangular plate (80 mm × 80 mm × 3.0 mm thick). Using this test piece, the maximum voltage at which tracking failure did not occur was measured in accordance with IEC 60112 (2003). A 0.1% aqueous ammonium chloride solution was used as the electrolyte. The higher this maximum voltage, the better the tracking resistance.

[0059] (4) Flame-retardant resin composition pellets were supplied to an injection molding machine (SE-50D) manufactured by Sumitomo Heavy Industries, Ltd., with the cylinder temperature set to the melting point of the thermoplastic resin + 30°C and the mold temperature to 80°C or 145°C. Using a mold with the UL test specimen shape specified in UL94, injection molding was performed under the following conditions: injection speed of 120 mm / s, injection pressure equal to the injection pressure when the tip of the test specimen was filled plus 5 MPa, injection time of 8 s, and cooling time of 10 s to obtain an evaluation test specimen. The flame retardancy of this test specimen was evaluated in accordance with the UL94 vertical test. The flame retardancy was ranked in the order of V-0 > V-1 > V-2, with those that did not meet V-2 being indicated as V-out. A test specimen with a thickness of 1.5 mm was used, and it is preferable that a test specimen thickness of 1.5 mm or less showed V-0.

[0060] (5) Large molded product assembly resin composition pellets were supplied to a JSW Corporation injection molding machine (J1000ELIII-3900H) set to cylinder temperature: (A) melting point of thermoplastic resin + 30°C, mold temperature 70°C or 130°C, and injection molding was performed under the conditions of injection speed 100 mm / s, holding pressure speed 50 mm / s, and cooling time 250 s to obtain the evaluation molded product shown in Figure 1. The obtained molded product was assembled to a 7 mm thick steel plate with an M30 screw and a torque of 40 N / m, and the occurrence of cracks was evaluated. Evaluation was performed at each level N=30, and the fewer the number of cracks that occurred, the better the assembly performance, and it was judged that it could withstand practical use if the number of cracks that occurred was 5 or less.

[0061] (6) Heat resistance of large molded products An evaluation molded product shown in Figure 1 was obtained using the same method as in (5). The obtained molded product was heated in an oven at 150°C for 120 minutes. Evaluation was performed at each level N=30, and it was determined that the fewer the number of deformations that occurred on the surface of the molded product, the better the heat resistance if there was no deformation, and if the number of deformations was 5 or less, it was determined that it was suitable for practical use.

[0062] (7) Epoxy potting properties of large molded products An evaluation molded product shown in Figure 1 was obtained using the same method as in (5). After installing copper litz wire in the coil holding part 1 of the obtained molded product, the coil holding part was potted using DP460EG, a two-component epoxy resin manufactured by 3M, and heated in an oven at 100°C for 30 minutes. After returning to room temperature, the occurrence of cracks was evaluated. Evaluations were performed at each level N=30, and it was determined that the epoxy potting properties were better the fewer cracks that occurred, and that it was acceptable for practical use if the number of cracks was 5 or less.

[0063] [Examples 1-5, Comparative Examples 1 and 2] Using a twin-screw extruder (TEM-26SS, manufactured by Toshiba Machine Co., Ltd.) with a 26 mm diameter intermediate addition port, with the cylinder temperature set to (A) the melting point of the thermoplastic resin + 35°C and the screw rotation speed set to 300 rpm, (A) thermoplastic resin was melted by adding (C) non-fibrous filler, (D) flame retardant, and (E) flame retardant aid to 100 parts by mass of thermoplastic resin from the raw material supply port in the mass ratios shown in Table 1, and (B) fibrous filler was supplied from the intermediate addition port in the mass ratios shown in Table 1, and the mixture was melted and kneaded at a discharge rate of 30 kg / hour to obtain thermoplastic resin composition pellets. Thermoplastic resin molded products were made using these thermoplastic resin composition pellets as described above, and their respective properties were evaluated. The results are shown in Table 1.

[0064]

[0065] Examples 1 to 5, compared to Comparative Examples 1 and 2, demonstrated excellent product assembly, heat resistance, and potting properties even in large molded products, as evidenced by achieving a dielectric breakdown voltage of 10 kV / mm or higher according to IEC 60243, PLC class IIIIC or higher in tracking resistance evaluation according to IEC 60112, a load deflection temperature of 150°C or higher at 1.8 MPa, and a flatness of 15 mm or less. This made them suitable for wireless power supply products.

[0066] Examples 2 and 3 showed that by applying (B) flattened glass fibers as a fibrous filler and (C) a non-fibrous filler, the flatness could be further improved, and even for large molded products, the product assembly, heat resistance, and potting properties were further enhanced.

[0067] Despite being a large molded product, it offers excellent product assembly, heat resistance, and potting properties, making it ideal for wireless power supply applications.

[0068] 1. Coil holding part 2. Metal collar with a hole diameter (φ) of 20 mm

Claims

A molded article for wireless power transfer, made by molding a thermoplastic resin composition having a dielectric breakdown voltage of 10 kV / mm or more in accordance with IEC 60243, PLC class IIIIC or higher in tracking resistance evaluation in accordance with IEC 60112, and a load deflection temperature of 150°C or more at 1.8 MPa, having dimensions of 400 mm to 1000 mm in width, 400 mm to 2000 mm in length, and 2 mm to 20 mm in thickness, with a flatness of 15 mm or less. The molded article for wireless power supply according to claim 1, wherein the thermoplastic resin composition contains a fibrous filler. A molded article for wireless power supply according to claim 1 or 2, wherein the thermoplastic resin composition is V-0 at a thickness of 1.5 mm or more in a flammability evaluation in accordance with UL94. A molded article for wireless power supply according to claim 1 or 2, wherein the coefficient of linear expansion of the thermoplastic resin composition at -40°C to 150°C is 100 ppm / K or less. A molded article for wireless power supply according to claim 1 or 2, wherein the thermoplastic resin composition has a tensile modulus of 10 GPa or more. The molded article for wireless power supply according to claim 1 or 2, wherein the thermoplastic resin composition is a resin composition comprising a polyarylene sulfide resin, an aromatic polyamide resin, or a polyphenylene ether resin.

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