Resin composition, coating material or insulating material, and molded body

Abstract

A resin composition according to an embodiment of the present invention includes: a base resin which is at least one resin selected from the group consisting of liquid crystal resins and polyphenylene sulfide resins; and a thermally conductive filler, wherein the thermally conductive filler includes a filler (A) having an isotropic shape and a filler (B) having a scale-like or plate-like anisotropic shape.

Description

Resin composition, coating material or insulating material, and molded article

[0001] The present invention relates to a resin composition, a coating material or an insulating material, and a molded article.

[0002] Patent Document 1 discloses a resin composition obtained by melt-kneading a mixture containing 100 parts by mass of (A) polyarylene sulfide resin and 25 to 280 parts by mass of (B) syndiotactic polystyrene resin.

[0003] Patent Document 2 discloses a resin composition comprising a melt-processable fluororesin having at least one functional group selected from the group consisting of a carbonyl group-containing group and a hydroxy group, at least one non-fluorine-containing resin selected from the group consisting of a liquid crystal polymer, a polyarylene sulfide, and an aromatic polyether ketone, and boron nitride particles.

[0004] Patent Document 3 discloses a polyphenylene sulfide resin composition obtained by blending (a) 100 parts by weight of polyphenylene sulfide resin with (b) 0.1 to 150 parts by weight of glass fiber made of glass having a relative dielectric constant of 5.5 or less, and (c) 0.1 to 10 parts by weight of a silane coupling agent.

[0005] Japanese Patent Publication No. 2014-177617 Japanese Patent Publication No. 2021-143330 Japanese Patent Publication No. 2019-131685

[0006] Electric motors in the industrial and automotive sectors are required to have higher power output and improved power density through miniaturization in order to improve power performance and fuel efficiency. The smaller the motor and the higher the torque, the greater the heat generation, which increases temperature and reduces efficiency. Therefore, to improve the efficiency of motors, high thermal conductivity of the components is required, especially in the thickness direction, to efficiently transfer heat generated from the heat-generating parts to the cooling parts.

[0007] An object of one aspect of the present invention is to provide a resin composition having high thermal conductivity in the thickness direction.

[0008] In order to solve the above problems, a resin composition according to one embodiment of the present invention includes a base resin that is at least one selected from the group consisting of a liquid crystal resin and a polyphenylene sulfide resin, and a thermally conductive filler, wherein the thermally conductive filler includes a filler (A) having an isotropic shape and a filler (B) having a scaly or plate-like anisotropic shape.

[0009] According to one aspect of the present invention, a resin composition having high thermal conductivity in the thickness direction can be realized.

[0010] Hereinafter, one embodiment of the present invention will be described in detail. In this specification, unless otherwise specified, the expression "A to B" representing a range of numerical values ​​means "A or more and B or less."

[0011] [1. Resin Composition] A resin composition according to one embodiment of the present invention includes a base resin that is at least one selected from the group consisting of a liquid crystal resin and a polyphenylene sulfide resin, and a thermally conductive filler, wherein the thermally conductive filler includes a filler (A) having an isotropic shape and a filler (B) having a scaly or plate-like anisotropic shape.

[0012] A resin composition according to one embodiment of the present invention is a resin composition in which the base resin is at least one selected from the group consisting of liquid crystal resins and polyphenylene sulfide resins, and contains a thermally conductive filler including a filler (A) having an isotropic shape and a filler (B) having a scaly or plate-like anisotropic shape, thereby making it possible to realize a resin composition with high thermal conductivity in the thickness direction.

[0013] <Base Resin> The base resin is at least one selected from the group consisting of liquid crystal resins and polyphenylene sulfide resins.

[0014] (Liquid Crystal Resin) A liquid crystal resin (hereinafter also referred to as "LCP") is a polymer that exhibits liquid crystallinity in a molten state. The type of liquid crystal resin is not particularly limited, but a thermotropic liquid crystal resin is preferable. A thermotropic liquid crystal resin is a polymer that becomes a liquid crystal state such as a nematic state within a certain temperature range.

[0015] The type of thermotropic liquid crystal resin is not particularly limited. Thermotropic liquid crystal resins are classified according to heat resistance. For example, type I liquid crystal resins are liquid crystal resins having a deflection temperature under load (DTUL) of 300°C or higher at 1.80 MPa, type 1.5 and type II liquid crystal resins are liquid crystal resins having a DTUL of 210°C or higher but lower than 300°C at 1.80 MPa, and type III liquid crystal resins are liquid crystal resins having a DTUL of 60°C or higher but lower than 210°C at 1.80 MPa.

[0016] Examples of thermotropic liquid crystal resins include: type I liquid crystal resins (such as biphenol / benzoic acid / parahydroxybenzoic acid (POB) copolymers); type 1.5 liquid crystal resins (such as biphenol / benzoic acid / hydroxynaphthoic acid (HNA) / parahydroxybenzoic acid (POB) copolymers); type II liquid crystal resins (such as hydroxynaphthoic acid (HNA) / POB copolymers); and type III liquid crystal resins (such as POB / ethylene terephthalate copolymers).

[0017] Although not particularly limited, among these, from the viewpoints of the kneading temperature and the liquid crystal transition temperature, 1.5-type liquid crystal resin, II-type liquid crystal resin, or III-type liquid crystal resin is preferable. The liquid crystal resin may be used alone or in combination of two or more.

[0018] Although the liquid crystal transition onset temperature of the LCP is not particularly limited, when a fluororesin is contained as an alloy component, it is preferably lower than the processing temperature of the fluororesin. For example, when the fluororesin is polytetrafluoroethylene (PTFE), the processing temperature of PTFE is 327°C or higher, so the liquid crystal transition onset temperature of the LCP is preferably lower than that.

[0019] LCP can be produced by known methods (see, for example, Japanese Patent Application Laid-Open No. 62-250029).

[0020] The LCP used in one embodiment of the present invention preferably has a melt viscosity of 1 to 100 Pa sec, more preferably 5 to 50 Pa sec, and even more preferably 7 to 30 Pa sec at a resin temperature of 340°C and a shear rate of 1200 (1 / sec). The melt viscosity of the LCP is measured using a capillary rheometer.

[0021] Although the dielectric constant of the LCP is not particularly limited, from the viewpoint of the dielectric constant of the composite material, the dielectric constant measured at 1 MHz is preferably 4.0 or less, and more preferably 3.5 or less. The dielectric constant of the LCP refers to a value measured by an automatic balancing bridge method.

[0022] An example of a commercially available LCP product is "A6000" (relative dielectric constant: 3.1 (1 MHz)) manufactured by Ueno Pharmaceutical Co., Ltd.

[0023] By including an LCP as a base resin in the resin composition according to one embodiment of the present invention, it is possible to obtain better molding flowability of the resin composition. For example, when an LCP is included as a base resin, the melt viscosity is reduced more in a shear rate range of 1200 (1 / sec) or more than when only a polyphenylene sulfide resin described below is used, and thus better flowability is obtained.

[0024] (Polyphenylene sulfide resin) Polyphenylene sulfide resin (hereinafter also referred to as "PPS") is a polymer having a structural unit represented by the following formula (I).

[0025] (In formula (I), Ar represents a phenylene-containing group, and S represents sulfur.) If the structural unit represented by formula (I) above is defined as 1 mole (basic mole), the PPS used in the present invention is a polymer containing this structural unit in an amount of usually 50 mol % or more, preferably 70 mol % or more, and more preferably 90 mol % or more.

[0026] In the above formula (I), Ar may have a group other than phenylene, and the phenylene may have a substituent. The number of carbon atoms in Ar is, for example, 6 to 20. Examples of Ar include the following structures.

[0027] PPS may be a homopolymer consisting of the same structural unit, a copolymer having two or more different structural units, or a mixture thereof. The copolymer may be a random copolymer or a block copolymer.

[0028] The polymer chain of PPS may be partially substituted with another polymer, as long as the effects of the present invention are not impaired. Examples of the polymer to be substituted include polyester-based polymers, polyarylene ether-based polymers, polystyrene-based polymers, polyolefin-based polymers, fluorine-containing polymers, polyolefin-based elastomers, and silicone-based elastomers.

[0029] PPS can be produced by known methods, for example, as described in Japanese Patent Publication Nos. 45-3368 and 52-12240. PPS may be heated in air to increase its molecular weight, or may be chemically modified with a compound such as an acid anhydride.

[0030] The PPS used in one embodiment of the present invention preferably has a melt viscosity of 1 to 100 Pa sec, more preferably 5 to 50 Pa sec, and even more preferably 10 to 30 Pa sec, at a resin temperature of 310°C and a shear rate of 1200 (1 / sec). The melt viscosity of PPS is measured with a capillary rheometer.

[0031] One type of PPS may be used alone, or two or more types may be used in combination.

[0032] Since PPS is a crystalline resin, it has excellent heat resistance and chemical resistance. Therefore, by including PPS as a base resin in the resin composition according to one aspect of the present invention, the heat resistance and chemical resistance of the resin composition can be improved.

[0033] Although the relative dielectric constant of PPS is not particularly limited, from the viewpoint of the relative dielectric constant of the composite material, the relative dielectric constant measured at 1 MHz is preferably 4.0 or less, and more preferably 3.7 or less. The relative dielectric constant of PPS refers to a value measured by an automatic balancing bridge method.

[0034] Commercially available PPS products include "MB652-290G" manufactured by DIC Corporation (dielectric constant: 3.6 (1 MHz), melt viscosity: 13 Pa·sec / 310°C, 1200 sec) －１ ) etc.

[0035] (Base Resin Content) Furthermore, from the viewpoint of fluidity, the content of the base resin in the resin composition according to one aspect of the present invention is preferably 40% by volume or more, more preferably 50% by volume or more. Furthermore, from the viewpoint of thermal conductivity, it is preferably 80% by volume or less, more preferably 70% by volume or less. When the base resin is an LCP, by having the content of the base resin in the resin composition within the above-mentioned range, the molding fluidity of the resin composition can be sufficiently improved.

[0036] Furthermore, when the base resin is PPS, by ensuring that the content of the base resin in the resin composition is within the above range, the heat resistance and chemical resistance of the resin composition can be sufficiently improved.

[0037] Furthermore, when the base resin is a mixture of LCP and PPS, the ratio of the LCP content to the PPS content in the base resin can be appropriately adjusted depending on the purpose of the resin composition and is not particularly limited. From the viewpoint of adhesion to dissimilar materials such as metals, the ratio of the LCP content to the PPS content in the base resin (LCP:PPS) is preferably 1:0.05 or more, more preferably 1:0.1 or more, by mass. From the viewpoint of strength, the ratio of the LCP content to the PPS content (LCP:PPS) in the base resin is preferably 1:0.4 or less, more preferably 1:0.3 or less, by mass.

[0038] <Thermal Conductive Filler> Examples of thermally conductive fillers include conventionally known fillers used for the purpose of imparting thermal conductivity. The thermal conductivity of the thermally conductive filler is preferably high from the viewpoint of improving the thermal conductivity of the resin composition. Specifically, the thermal conductivity of the thermally conductive filler is preferably 1.0 W / m·K or more, more preferably 2.0 W / m·K or more, and even more preferably 3.0 W / m·K or more. When the thermally conductive filler is made of a mineral and a raw stone is available, the thermal conductivity of the thermally conductive filler is measured by the laser flash method (JIS R 1611) on a thin plate cut from the raw stone. However, when a thin plate for thermal conductivity measurement cannot be obtained (for example, when an artificial filler is obtained as a powder from the beginning), the thermal effusivity of each filler is measured under a microscope using a photothermal reflectance method with a thermal property microscope, and the thermal conductivity is calculated.

[0039] Furthermore, from the viewpoint of suppressing an increase in the dielectric constant of the resin composition, it is preferable to select a thermally conductive filler with a low dielectric constant. Specifically, the dielectric constant of the thermally conductive filler measured at 1 MHz is preferably 5.0 or less, more preferably 4.0 or less, and even more preferably 3.0 or less. Furthermore, the lower limit of the dielectric constant of the thermally conductive filler is not particularly limited. The dielectric constant of the thermally conductive filler can be determined using a coaxial probe method. More specifically, a viscous blend is prepared by blending approximately 70 to 90 volume percent of the thermally conductive filler with a binder resin having a known dielectric constant, and then compression-molded into a flat plate and cured to form a test specimen. The shape is approximately 60 x 60 x 1.0 mmt. Using this flat plate-shaped test specimen, the dielectric constant at 1 MHz is measured using an automatic balancing bridge method (LCR meter). The dielectric constant of the thermally conductive filler is calculated back from the dielectric constant of the obtained composition and the volume fraction and dielectric constant of the binder resin using Bruggeman's rule of mixtures.

[0040] The thermally conductive filler includes a filler (A) having an isotropic shape and a filler (B) having a scale-like or plate-like anisotropic shape. By including such a thermally conductive filler, the resin composition according to one embodiment of the present invention can achieve a resin composition with high thermal conductivity in the thickness direction. The mechanism of action is believed to be as follows. Specifically, by arranging the filler (B) having a scale-like or plate-like anisotropic shape in the gaps between the filler (A) having an isotropic shape dispersed in the resin, or in contact with the filler (A) having an isotropic shape, it is believed that heat transfer between the two fillers can be efficiently performed, and a heat conduction path can be generated in the thickness direction as well.

[0041] (Filler (A) Having an Isotropic Shape) The filler (A) having an isotropic shape (hereinafter also referred to as "thermally conductive filler (A)") is not particularly limited as long as it is a thermally conductive filler having an isotropic shape. In this specification, an isotropic shape means a shape having an aspect ratio (major axis diameter / minor axis diameter) of 1.0 or more and less than 3.0. The aspect ratio (major axis diameter / minor axis diameter) is measured by taking a two-dimensional image of the filler and determining the circumscribing circle by image analysis. This diameter is defined as the major axis diameter. Meanwhile, an inscribing circle is determined and this diameter is defined as the minor axis diameter.

[0042] From the viewpoint of warping of a molded article obtained by injection molding the resin composition, the isotropic shape is preferably a shape having an aspect ratio (major axis diameter / minor axis diameter) of 1.0 or more and less than 3.0, more preferably a shape having an aspect ratio of 1.0 or more and 2.5 or less, and even more preferably a shape having an aspect ratio of 1.0 or more and 2.0 or less.

[0043] Examples of isotropic shapes include spherical shapes and regular polyhedron shapes, but the shape is not limited to these as long as the aspect ratio (major axis diameter / minor axis diameter) is within the above-mentioned range, and an irregular shape with an aspect ratio (major axis diameter / minor axis diameter) within the above-mentioned range may also be used. In this specification, "irregular shape" is intended to mean a shape other than a sphere or a regular polyhedron that is not constant in shape or size and has multiple flat or curved surfaces.

[0044] The thermally conductive filler (A) may be either an inorganic filler or an organic filler. Examples of the thermally conductive filler (A) include magnesite, magnesium oxide, granular graphite, and granular boehmite. The thermally conductive filler (A) may be used alone or in combination of two or more. Among these, from the viewpoint of the relative dielectric constant, the thermally conductive filler (A) is preferably one or more selected from magnesite and magnesium oxide, and more preferably magnesite.

[0045] The average particle size of the thermally conductive filler (A) is not particularly limited and can be selected appropriately. The average particle size of the thermally conductive filler (A) can be, for example, 3 μm or more, and may be 5 μm or more. The upper limit of the average particle size of the thermally conductive filler (A) can be 50 μm or less, and may be 30 μm or less. From the viewpoint of combination with the thermally conductive filler (B), the average particle size of the thermally conductive filler (A) is preferably 5 μm or more and 30 μm or less. The average particle size of the thermally conductive filler (A) is a value measured by measuring the particle size distribution using a laser diffraction scattering method.

[0046] Commercially available examples of the thermally conductive filler (A) include "Magthermo (registered trademark) MS-L" (synthetic magnesite, average particle size 8 μm, thermal conductivity 15.0 W / mK, relative dielectric constant 4.8 (1 MHz)) manufactured by Konoshima Chemical Co., Ltd.

[0047] (Filler (B) Having a Scaly or Plate-Like Anisotropic Shape) The filler (B) having a scaly or plate-like anisotropic shape (hereinafter also referred to as "thermally conductive filler (B)") is not particularly limited as long as it is a scaly or plate-like thermally conductive filler having an anisotropic shape. In this specification, an anisotropic shape means a shape having an aspect ratio (major axis diameter / minor axis diameter) of 3 or more. The major axis diameter and minor axis diameter are as described above. From the viewpoint of thermal conductivity, the anisotropic shape is preferably a shape having an aspect ratio (major axis diameter / minor axis diameter) of 5 or more, more preferably a shape having an aspect ratio of 10 or more. Furthermore, from the viewpoint of compoundability, the aspect ratio (major axis diameter / minor axis diameter) is preferably a shape having an aspect ratio (major axis diameter / minor axis diameter) of 200 or less, more preferably a shape having an aspect ratio of 100 or less, and even more preferably a shape having an aspect ratio of 50 or less.

[0048] The thermally conductive filler (B) may have an anisotropic flake or plate shape, but preferably has a flake or plate shape with an aspect ratio (major axis diameter / minor axis diameter) that satisfies the above-mentioned range.

[0049] The thermally conductive filler (B) may be either an inorganic filler or an organic filler. Examples of the thermally conductive filler (B) include plate-like talc, scaly talc, plate-like boehmite, scaly boehmite, plate-like graphite, and scaly graphite. The thermally conductive filler (B) may be used alone or in combination of two or more. Among these, from the viewpoint of the relative dielectric constant, the thermally conductive filler (B) is preferably scaly or plate-like talc.

[0050] The average particle size of the thermally conductive filler (B) is not particularly limited and can be selected appropriately. The average particle size of the thermally conductive filler (B) can be, for example, 5 μm or more, and may be 10 μm or more. The upper limit of the average particle size of the thermally conductive filler (B) can be 100 μm or less, and may be 50 μm or less. From the viewpoint of combination with the thermally conductive filler (A), the average particle size of the thermally conductive filler (B) is preferably 5 μm or more and 40 μm or less. The average particle size of the thermally conductive filler (B) is a value measured by a laser diffraction scattering method, similar to that of the thermally conductive filler (A).

[0051] Commercially available thermally conductive fillers (B) include "MS-K" (talc, average particle size 16 μm, thermal conductivity 2.0 W / mK, relative dielectric constant 4.2 (1 MHz)) manufactured by Nippon Talc Co., Ltd.

[0052] (Preferred Combination of Thermally Conductive Filler (A) and Thermally Conductive Filler (B)) From the viewpoint of obtaining a resin composition having high thermal conductivity in the thickness direction, it is preferable that the thermally conductive filler (A) is at least one selected from the group consisting of magnesite, magnesium oxide, granular boehmite, and granular graphite, and that the filler (B) is at least one selected from the group consisting of plate-like talc, flaky talc, plate-like boehmite, flaky boehmite, plate-like graphite, and flaky graphite. For example, a combination in which the thermally conductive filler (A) is magnesite and the thermally conductive filler (B) is flaky or plate-like talc can be mentioned. Among these, from the viewpoint of relative dielectric constant, a combination in which the thermally conductive filler (A) is magnesite and the thermally conductive filler (B) is flaky or plate-like talc is more preferable.

[0053] (Thermal Conductive Filler Content) The content of the thermal conductive filler in the resin composition according to one aspect of the present invention is not particularly limited, but from the viewpoint of thermal conductivity, it is preferably 25% by mass or more, more preferably 30% by mass or more, and from the viewpoint of flowability, it is preferably 55% by mass or less, more preferably 50% by mass or less.

[0054] In addition, the total content of the thermally conductive filler (A) and the thermally conductive filler (B) relative to the total amount of the thermally conductive filler is not particularly limited. From the viewpoint of thermal conductivity, the total content of the thermally conductive filler (A) and the thermally conductive filler (B) relative to the total amount of the thermally conductive filler is preferably 50 mass% or more, more preferably 60 mass% or more. In addition, the upper limit of the total content of the thermally conductive filler (A) and the thermally conductive filler (B) relative to the total amount of the thermally conductive filler is not particularly limited, and may be 100 mass%.

[0055] The ratio of the content of the thermally conductive filler (A) to the content of the thermally conductive filler (B) can be appropriately adjusted depending on the purpose of the resin composition and is not particularly limited. From the viewpoint of fluidity, the ratio of the content of the thermally conductive filler (A) to the content of the thermally conductive filler (B) ((A):(B)) is preferably in the range of 10:90 or more and 80:20 or less in volume ratio, more preferably in the range of 20:80 or more and 50:50 or less, even more preferably in the range of 20:80 or more and 40:60 or less, and most preferably in the range of 20:80 or more and 30:70 or less. Furthermore, from the viewpoint of the anisotropy of thermal conductivity, the ratio of the content of the thermally conductive filler (A) to the content of the thermally conductive filler (B) ((A):(B)) is preferably in the range of 10:90 or more and 80:20 or less in volume ratio, more preferably in the range of 20:80 or more and 50:50 or less, and most preferably in the range of 20:80 or more and 30:70 or less.

[0056] <Fibrous Filler> The resin composition according to an embodiment of the present invention preferably further comprises a fibrous filler. By further comprising a fibrous filler, the mechanical strength of the resin composition can be improved.

[0057] Examples of the fibrous filler include conventionally known fibrous fillers used for the purpose of enhancing the mechanical strength of resin compositions. The fibrous filler may be either an inorganic filler or an organic filler. Examples of the fibrous filler include glass fiber, whiskers, and aramid fiber. One type of fibrous filler may be used alone, or two or more types may be used in combination. Among these, from the viewpoint of improving strength, glass fiber is preferred as the fibrous filler. The aspect ratio of the fibrous filler can be expressed as fiber length / fiber diameter.

[0058] (Glass Fiber) The glass fiber is not particularly limited, and examples thereof include conventionally known glass fibers used for the purpose of enhancing the mechanical strength of a resin composition. Such glass fibers include, for example, SiO ２ , Al ２ O ３ , B ２O ３ , CaO, MgO, LiO ２ , Na ２ O.K. ２ O and TiO ２ The glass fiber is made of glass containing one or more components selected from the group consisting of: ２ 50 to 70 mass% of Al ２ O ３ 1 to 20 mass %, B ２ O ３ 5 to 30 mass%, CaO 0.1 to 25 mass%, MgO 0 to 7 mass%, LiO ２ 0 to 1 mass %, NaO ２ is 0 to 2 mass%, K ２ O is 0 to 1.5 mass %, TiO ２ It is preferable that the content of the hydroxybenzoates is in the range of 0 to 5 mass %.

[0059] As such glass fibers, glass fibers made of conventionally known E-glass, S-glass, C-glass, D-glass, ECR glass, AR glass, etc. are commercially available. One type of glass fiber may be used alone, or two or more types may be used in combination. Among these, glass fibers made of E-glass are widely used. Furthermore, from the viewpoint of dielectric constant, glass fibers having a dielectric constant of 5.5 or less measured at 1 GHz are preferably used.

[0060] By blending glass fibers composed of glass having a relative dielectric constant of 5.5 or less measured at 1 GHz as the glass fibers in the resin composition according to one aspect of the present invention, it is possible to control the relative dielectric constant of the resin composition low and improve the mechanical strength. The relative dielectric constant of the glass constituting the glass fibers, measured at 1 GHz, is preferably 3.7 or more and 5.5 or less. From the viewpoint of obtaining the desired effect, the relative dielectric constant of the glass fiber, measured at 1 GHz, is preferably as low as possible, more preferably 5.0 or less, and even more preferably 4.8 or less. However, SiO ２ In the glass composed of SiO ２ The practical lower limit is 3.7, which is the relative permittivity measured at 1 GHz for a single material.

[0061] The composition of the glass constituting the glass fiber having a relative dielectric constant of 5.5 or less measured at 1 GHz is not particularly limited, but the composition of each of the above-mentioned components is preferably SiO ２ 50 to 70 mass% of Al ２ O ３ 1 to 20 mass %, B ２ O ３ 15 to 30 mass %, CaO 0.1 to 5 mass %, MgO 0.1 to 5 mass %, LiO ２ 0 to 1 mass %, NaO ２ 0 to 1.5 mass %, K ２ O is 0 to 1.5 mass %, TiO ２ It is preferable that the glass is composed of a glass having a content of 0 to 5 mass %.

[0062] The glass that makes up the glass fiber with a relative dielectric constant of 5.5 or less measured at 1 GHz has a B ２ O ３ and tends to contain less CaO.

[0063] The dielectric constant of the glass can be determined by placing the glass in a platinum crucible and melting it in an electric furnace at about 1580°C for 4 to 15 hours to obtain a homogeneous molten glass. The molten glass is then slowly cooled to obtain a glass mass, which is then annealed to remove strain. A flat test piece is then prepared from the mass using a cutting machine, such as a diamond cutter and a polishing machine. The dielectric constant of the test piece at 1 GHz can be determined in accordance with JIS C2565:1992.

[0064] The surface of the glass fiber is preferably pretreated with a coupling agent such as an isocyanate compound, an organic silane compound, an organic titanate compound, an organic borane compound, or an epoxy compound, which improves the bundling ability of the glass fiber, the dispersibility in the resin composition, and the adhesion between the glass fiber and the resin.

[0065] The shape of the glass fiber is not particularly limited, but from the viewpoint of fluidity, the fiber diameter is preferably 3 μm or more, more preferably 5 μm or more, and even more preferably 7 μm or more. From the viewpoint of improving strength, the fiber diameter is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 11 μm or less. The fiber diameter of a glass fiber means the diameter of a circle obtained by converting a cross section perpendicular to the fiber axis into a circle having the same area as the area of ​​that cross section.

[0066] The fiber diameter of the glass fiber is a number average, and is measured and calculated by performing image analysis using a digital microscope on 50 or more arbitrarily selected glass fibers. The cross-sectional shape of the glass fiber is usually circular, but it may also be a flat circular or elliptical shape. A typical example of a flat circular cross-sectional shape is a glass fiber having a flat circular cross-sectional shape with a major axis of 28 μm and a minor axis of 7 μm.

[0067] Furthermore, from the viewpoint of compoundability (handleability), the glass fibers are preferably short fibers (for example, chopped fibers (chopped strands), milled fibers, etc.), and specifically, the fiber length is preferably 10 mm or less, more preferably 6 mm or less, even more preferably 5 mm or less, and even more preferably 3 mm or less. Furthermore, from the viewpoint of improving strength, the fiber length is preferably 100 μm or more, more preferably 200 μm or more, even more preferably 300 μm or more, and even more preferably 600 μm or more. The fiber length of the glass fibers is a number average, and is a value calculated by measuring 50 or more arbitrarily selected glass fibers by image analysis of optical microscope images.

[0068] Examples of commercially available glass fibers include "CN 3J-256" manufactured by Nitto Boseki Co., Ltd. (fiber diameter 11 μm, chopped fiber, relative dielectric constant 4.8 (1 GHz)); and "E Glass Fiber Chopped Strand ECS 03 T-756H" manufactured by Nippon Electric Glass Co., Ltd. (fiber diameter 10.5 μm, relative dielectric constant 6.8 (1 GHz)).

[0069] (Content of fibrous filler) The content of the fibrous filler in the resin composition according to one aspect of the present invention is not particularly limited, but from the viewpoint of improving strength, it is preferably 10% by mass or more, more preferably 20% by mass or more, and from the viewpoint of flowability, it is preferably 40% by mass or less, more preferably 30% by mass or less.

[0070] <Resin (alloy component) of a type different from the base resin> The resin composition according to one embodiment of the present invention does not need to contain a resin of a type different from the base resin, but preferably further contains a resin of a type different from the base resin. Adding a resin of a type different from the base resin to the resin composition according to one embodiment of the present invention is effective in improving mechanical properties and dielectric properties. In this specification, a resin of a type different from the base resin may be referred to as an "alloy component."

[0071] The type of alloy component is not particularly limited and can be appropriately selected depending on the purpose. Examples of alloy components include polyamide resins, long-chain semi-aromatic polyamide resins (e.g., PA9T, PA10T, etc.), polyester resins, polyetherimide resins, polyethersulfone resins, polyphenylene ether resins, thermoplastic elastomers (olefin-based, polyamide-based, polyester-based), fluororesins, silicone resins, epoxy resins, syndiotactic polystyrene resins, polyarylate resins, etc. The alloy components may be used alone or in combination of two or more.

[0072] From the viewpoint of improving the dielectric properties of the resin composition, the alloy component is preferably a conventionally known alloy component resin that has the effect of lowering the dielectric constant of the base resin. For example, the alloy component resin is preferably a resin having a dielectric constant lower than that of the base resin. For example, the dielectric constant measured at 1 MHz is preferably 3.0 or less. Such a resin is preferably at least one selected from the group consisting of fluororesins, unmodified polyphenylene ether resins, long-chain semi-aromatic polyamide resins, and polyarylate resins, and more preferably a fluororesin. Fluororesins will be described in detail later.

[0073] (Alloy Component Content) The content of the alloy component in the resin composition according to one embodiment of the present invention is not particularly limited, but from the viewpoint of the dielectric constant reduction effect, it is preferably 5% by mass or more, more preferably 7% by mass or more, and even more preferably 10% by mass or more. Furthermore, from the viewpoint of flowability, it is preferably 20% by mass or less, and more preferably 15% by mass or less.

[0074] (Fluorine resin) The type of fluororesin is not particularly limited, and can be the conventionally known fluororesin that is used as the alloy component of resin composition.As this fluororesin, for example, can be listed: polytetrafluoroethylene [PTFE]; tetrafluoroethylene [TFE] / perfluoro(alkyl vinyl ether) [PAVE] copolymer [PFA]; TFE / hexafluoropropylene [HFP] copolymer [FEP]; ethylene [Et] / TFE copolymer [ETFE]; Et / TFE / HFP copolymer [EFEP]; polychlorotrifluoroethylene [PCTFE]; chlorotrifluoroethylene [CTFE] / TFE copolymer; Et / CTFE copolymer; polyvinyl fluoride [PVF]; polyvinylidene fluoride [PVDF]; etc.

[0075] The PAVE is preferably a monomer represented by the following general formula (1): CF ２ =CF-ORf １ (1) (wherein, Rf １ represents a perfluoroalkyl group having 1 to 8 carbon atoms).

[0076] Specific examples of PAVE include perfluoro(methyl vinyl ether) [PMVE], perfluoro(ethyl vinyl ether) [PEVE], perfluoro(propyl vinyl ether) [PPVE], and perfluoro(butyl vinyl ether).

[0077] Among these fluororesins, PTFE is preferred from the viewpoint of processability.

[0078] The PTFE is not particularly limited, and known PTFE can be used. The PTFE may be sintered or unsintered. From the viewpoint of preventing re-agglomeration, powdered PTFE is preferred, and PTFE sintered at a sintering temperature of 360°C or higher is preferred. The PTFE preferably has a melting point of 320 to 335°C, more preferably 325 to 330°C, as measured by the DSC method. Furthermore, the relative dielectric constant measured at 1 MHz is preferably 3.0 or less.

[0079] The fluororesin can be produced by a known method (see, for example, Japanese Patent No. 5663839).

[0080] An example of a commercially available fluororesin is "KTL-610" (PTFE fine powder, relative dielectric constant 2.1 (1 MHz), melting point 325 to 330°C) manufactured by Kitamura Co., Ltd.

[0081] <Other Components> In addition to the components described above, the resin composition according to one aspect of the present invention may contain any additives such as antioxidants, nucleating agents, plasticizers, release agents, flame retardants, pigments, antistatic agents, etc., within the range that does not impair the effects of the present invention. These additives may be additives commonly used in the relevant technical field.

[0082] The content of each additive in the resin composition may be adjusted appropriately from the viewpoint of the performance expression of each additive. Furthermore, from the viewpoint of reducing the influence on the physical properties of the obtained molded article, the total content of the additives in the resin composition is preferably 5% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less.

[0083] <Properties and Form of Resin Composition> The level of thermal conductivity in the thickness direction of the resin composition according to one embodiment of the present invention is not particularly limited. For example, the resin composition according to one embodiment of the present invention preferably has a thickness thermal conductivity of 0.1 W / m·K or more, and more preferably 0.2 W / m·K or more. Such a resin composition has sufficiently high thermal conductivity in the thickness direction, and therefore has excellent heat dissipation properties. Therefore, it can be suitably used as a material for any article requiring high heat dissipation properties. The thickness thermal conductivity of the resin composition according to one embodiment of the present invention is a value measured by the method described in the examples below.

[0084] Furthermore, the resin composition according to one embodiment of the present invention contains a thermally conductive filler including a filler (A) having an isotropic shape and a filler (B) having an anisotropic shape, and thus has sufficiently high thermal conductivity in the in-plane direction. For example, the resin composition according to one embodiment of the present invention preferably has an in-plane thermal conductivity of 1.0 W / m·K or more, more preferably 1.2 W / m·K or more. The in-plane thermal conductivity of the resin composition according to one embodiment of the present invention is a value measured by the method described in the Examples below.

[0085] Furthermore, the resin composition according to one embodiment of the present invention preferably has a low dielectric constant. For example, the resin composition according to one embodiment of the present invention preferably has a dielectric constant of 5 or less, more preferably 4 or less. By having the dielectric constant within the above range, the resin composition can be suitably used in applications requiring low dielectric properties. Furthermore, the lower limit of the dielectric constant of the resin composition according to one embodiment of the present invention is not particularly limited. The dielectric constant of the resin composition according to one embodiment of the present invention is a value measured by the method described in the examples below.

[0086] Furthermore, the resin composition according to one aspect of the present invention preferably has high mechanical strength. For example, the resin composition according to one aspect of the present invention preferably has a tensile strength of 50 MPa or more, more preferably 70 MPa or more, and even more preferably 80 MPa or more. By having the relative dielectric constant within the above range, the resin composition can be suitably used in applications requiring high mechanical strength. Furthermore, the upper limit of the tensile strength of the resin composition according to one aspect of the present invention is not particularly limited. The tensile strength of the resin composition according to one aspect of the present invention is a value measured by the method described in the examples below.

[0087] Furthermore, the resin composition according to one embodiment of the present invention preferably has high molding fluidity. For example, the resin composition according to one embodiment of the present invention preferably has a spiral flow length of 150 mm or more, more preferably 170 mm or more. When the spiral flow length is within the above-mentioned range, the resin composition can be suitably used in applications requiring high molding fluidity. Furthermore, the upper limit of the spiral flow length of the resin composition according to one embodiment of the present invention is not particularly limited. The spiral flow length of the resin composition according to one embodiment of the present invention is a value measured by the method described in the examples below.

[0088] Furthermore, the resin composition according to one embodiment of the present invention preferably has high flame retardancy. For example, the resin composition according to one embodiment of the present invention preferably has a flame retardancy of V-2 or higher, preferably V-1 or higher, and more preferably V-0 or higher, in a flammability rating according to the UL94V standard when used as a 0.8 mm thick test piece. Such a resin composition can be suitably used in applications requiring high flame retardancy.

[0089] The form of the resin composition according to one aspect of the present invention is not particularly limited, and may be any form, such as powder, granules, pellets, etc. The resin composition according to one aspect of the present invention is preferably in the form of pellets, since it is easy to subject to injection molding.

[0090] <Uses of Resin Composition> A resin composition according to one embodiment of the present invention has high thermal conductivity in the thickness direction and excellent heat dissipation. While the use of the resin composition according to one embodiment of the present invention is not particularly limited, taking advantage of the above-mentioned features, it can be suitably used as a coating material or insulating material for electric wires. In this specification, "coating material" refers to a material used to mold coated parts, and "insulating material" refers to a material used to mold insulating parts. For example, electric motors in the industrial and automotive fields are required to have higher power output and improved power density for miniaturization in order to improve power performance and fuel efficiency. To improve the efficiency of motors, high thermal conductivity of the components is required, particularly high thermal conductivity in the thickness direction to efficiently transfer heat generated from heat-generating parts to cooling parts. For this reason, a resin composition according to one embodiment of the present invention can be particularly suitably used, for example, as a coating material for coil wires for electric motors. Specific examples of coated parts for electric motor coils formed from a coating material for electric motor coil wires are described below. Therefore, a resin composition according to one embodiment of the present invention can be used as a resin composition for coating materials.

[0091] Furthermore, the resin composition according to one embodiment of the present invention can control the relative dielectric constant to be low. Therefore, the resin composition according to one embodiment of the present invention can be particularly suitably used, for example, as an insulating material for electric motors. Specific examples of insulating parts for electric motors obtained by molding the insulating material for electric motors will be described later. Therefore, the resin composition according to one embodiment of the present invention can be used as a resin composition for insulating materials.

[0092] <Method for Producing Resin Composition> The resin composition according to one embodiment of the present invention can be produced by blending and melt-kneading a base resin, which is at least one selected from the group consisting of liquid crystal resins and polyphenylene sulfide resins, with a thermally conductive filler including a filler (A) having an isotropic shape and a filler (B) having an anisotropic shape. For example, the components can be blended and kneaded using a Henschel mixer, Banbury mixer, single-screw extruder, twin-screw extruder, multi-screw extruder, co-kneader, or the like. The heating temperature during kneading is typically in the range of 20°C to 60°C higher than the melting point of the resin.

[0093] Alternatively, the above components may be compounded and premixed (pre-blended) using a commonly used device (for example, a ribbon blender, a drum tumbler, etc.), and then kneaded using the above device.

[0094] [2. Coating material or insulating material] The coating material or insulating material according to one aspect of the present invention includes the resin composition described above. The coating material or insulating material according to one aspect of the present invention can be produced using the resin composition described above.

[0095] The method for producing a coating material or insulating material using the resin composition according to one embodiment of the present invention is not particularly limited, and known methods can be used. For example, the resin composition according to one embodiment of the present invention is melt-mixed with various additives as needed, and the resulting composition is fed into an extruder, melt-kneaded, and pelletized to produce a coating material or insulating material. Compounding equipment such as an extruder, a Henschel mixer, a kneader, a shaft kneader, a Banbury mixer, or a roll mill can be used as a means for mixing the composition.

[0096] [3. Molded Article] A molded article according to one embodiment of the present invention includes the resin composition described above. The molded article according to one embodiment of the present invention can be produced from the resin composition by, for example, injection molding, injection compression molding, extrusion molding, blow molding, press molding, vacuum molding, foam molding, or the like. The molded article according to one embodiment of the present invention may be, for example, a coated part or an insulating part.

[0097] The coated or insulating part according to one aspect of the present invention can be used, for example, in electric motors in the industrial and automotive fields.

[0098] <Coated Part> A coated part according to an embodiment of the present invention is formed by molding a coating material containing the resin composition according to the embodiment of the present invention. Specifically, the coated part according to an embodiment of the present invention is used for coated parts for electric wires formed by coating an electric wire with the coating material, motor insulators, coil terminal blocks, electric wire coatings, etc.

[0099] The method for producing a coated part using the coating material according to one embodiment of the present invention is not particularly limited, and any known method can be used. For example, a coated part can be produced by feeding a mixture containing the components of the resin composition according to one embodiment of the present invention into an extruder, melt-kneading the mixture to form pellets, and then feeding the pellets into an injection molding machine equipped with a predetermined mold to perform injection molding.

[0100] The thickness of the coated part is not particularly limited and can be determined appropriately taking into consideration, for example, the diameter of the electric wire.

[0101] <Insulating Component> An insulating component according to an aspect of the present invention is formed by molding an insulating material containing the resin composition according to the aspect of the present invention described above.

[0102] Specific examples of insulating parts formed by molding the insulating material according to one embodiment of the present invention include insulating parts for electric wires formed by coating an electric wire with an insulating material, motor insulators, coil terminal blocks, and electric wire coatings.

[0103] The method for producing a coated part using the coating material according to one embodiment of the present invention is not particularly limited, and any known method can be used. For example, the coated part can be produced by injection molding the coating material according to one embodiment of the present invention into an injection molding machine equipped with a predetermined mold. In addition to injection molding, the coated part may be produced from the above-described coating material by known methods such as injection compression molding, extrusion molding, blow molding, press molding, vacuum molding, and foam molding. The same applies to the method for producing an insulating part using the insulating material according to one embodiment of the present invention.

[0104] [Summary] [1] The resin composition according to aspect 1 of the present invention comprises a base resin which is at least one selected from the group consisting of a liquid crystal resin and a polyphenylene sulfide resin, and a thermally conductive filler, wherein the thermally conductive filler comprises a filler (A) having an isotropic shape and a filler (B) having a scaly or plate-like anisotropic shape.

[0105] [2] A resin composition according to Aspect 2 of the present invention is the resin composition according to Aspect 1, wherein the filler (A) having an isotropic shape is at least one selected from the group consisting of magnesite, magnesium oxide, granular boehmite, and granular graphite, and the filler (B) having a scaly or plate-like anisotropic shape may be at least one selected from the group consisting of scaly or plate-like talc, scaly or plate-like boehmite, and scaly or plate-like graphite.

[0106] [3] In the resin composition according to Aspect 3 of the present invention, in Aspect 1 or 2, the aspect ratio of the filler (A) having an isotropic shape may be 1.0 or more and less than 3.0, and the aspect ratio of the filler (B) having a scaly or plate-like anisotropic shape may be 3 or more and 200 or less.

[0107] [4] In the resin composition according to Aspect 4 of the present invention, in any one of Aspects 1 to 3, the filler (A) having an isotropic shape is preferably magnesite.

[0108] [5] A resin composition according to aspect 5 of the present invention is the resin composition according to any one of aspects 1 to 3, wherein the filler (B) having a scaly or plate-like anisotropic shape is scaly or plate-like talc.

[0109] [6] In the resin composition according to aspect 6 of the present invention, in any one of aspects 1 to 5, the content of the thermally conductive filler in the resin composition is preferably 25% by mass or more and 55% by mass or less.

[0110] [7] In the resin composition according to aspect 7 of the present invention, in any one of aspects 1 to 6, the ratio of the content of the filler (A) having an isotropic shape to the content of the filler (B) having a scaly or plate-like anisotropic shape is preferably 10:90 or more and 80:20 or less by volume.

[0111] [8] The resin composition according to aspect 8 of the present invention is preferably any one of aspects 1 to 7, further comprising a fibrous filler.

[0112] [9] A resin composition according to a ninth aspect of the present invention is the resin composition according to the eighth aspect, wherein the fibrous filler is glass fiber.

[0113]

[10] A resin composition according to a tenth aspect of the present invention is, in the above-mentioned ninth aspect, preferably wherein the glass fibers are glass fibers having a relative dielectric constant of 5.5 or less when measured at 1 GHz.

[0114]

[11] The resin composition according to Aspect 11 of the present invention is the resin composition according to any one of Aspects 1 to 10, which preferably further contains a fluororesin.

[0115]

[12] The resin composition according to Aspect 12 of the present invention may be a resin composition for a coating material or a resin composition for an insulating material in any one of Aspects 1 to 11 described above.

[0116]

[13] A coating material or insulating material according to aspect 13 of the present invention comprises the resin composition of any one of aspects 1 to 12.

[0117]

[14] A molded article according to a fourteenth aspect of the present invention comprises the resin composition of any one of the first to twelfth aspects.

[0118]

[15] A coated or insulating part according to aspect 15 of the present invention is made of the coating material or insulating material according to aspect 13.

[0119] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in the embodiments are also included in the technical scope of the present invention.

[0120] EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0121] [Raw Materials for Resin Composition] The raw materials for the resin compositions used in the Examples and Comparative Examples are as follows.

[0122] <Base Resin> Liquid crystal resin (LCP) (manufactured by Ueno Pharmaceutical Co., Ltd., A6000, 1.5-type liquid crystal resin, relative dielectric constant 3.1 (1 MHz), melt viscosity 10 Pa·sec / 340°C, 1200 sec)－１ Polyphenylene sulfide resin (PPS) (DIC Corporation, MB652-290G, relative dielectric constant 3.6 (1 MHz), melt viscosity 13 Pa·sec / 310°C, 1200 sec) －１ )

[0123] <Alloy component (a type of resin different from the base resin)> Fluorine resin (manufactured by Kitamura Co., Ltd., PTFE fine powder, KTL-610, relative dielectric constant 2.1 (1 MHz), melting point 325 to 330°C)

[0124] <Thermal conductive filler (A)> Synthetic magnesite (manufactured by Konoshima Chemical Co., Ltd., Magthermo (registered trademark) MS-L, average particle size 8 μm, thermal conductivity 15 W / mK, relative dielectric constant 4.8 (1 MHz), aspect ratio 1.0 or more and less than 3.0, isotropic shape)

[0125] <Thermal conductive filler (B)> Talc (manufactured by Nippon Talc Co., Ltd., MS-K, average particle size 16 μm, thermal conductivity 2.0 W / mK, relative dielectric constant 4.2 (1 MHz), aspect ratio 3 or more and 200 or less, plate-like)

[0126] <Fibrous filler> Glass fiber (NE-GF) (manufactured by Nitto Boseki Co., Ltd., CN 3J-256, fiber diameter 11 μm, chopped fiber, relative dielectric constant 4.8 (1 GHz), aspect ratio 272) General-purpose glass fiber (general-purpose GF) (manufactured by Nippon Electric Glass Co., Ltd., E-glass fiber chopped strand ECS 03 T-756H, fiber diameter 10.5 μm, relative dielectric constant 6.8 (1 GHz))

[0127] [Examples 1 to 14, Comparative Examples 1 and 2] Each component, except for the fibrous filler, was preblended at the compounding ratios shown in Tables 1 to 3. The preblended mixture was fed from the top of a twin-screw extruder TEM37SS (Shibaura Machine Co., Ltd.) with a screw diameter of 37 mm and a cylinder temperature set to 320°C (for PPS) or 340°C (for LCP), and the fibrous filler was melt-kneaded by side-feeding near the center of the screw. The strands extruded from the die were cooled on a cooling mesh conveyor and cut with a pelletizer to obtain pellets (resin composition). Various test pieces were prepared from these pellets using an injection molding machine, and the following evaluations were performed.

[0128] <Injection molding> Injection molding machine Si-50V-D75C (clamping force: 490 kN) manufactured by Toyo Machinery & Metal Co., Ltd. Cylinder temperature: 340°C if the base resin is LCP, 320°C if the base resin is PPS Mold temperature: 120°C if the base resin is LCP, 50°C if the base resin is PPS

[0129] [Evaluation] <Relative dielectric constant> For each of the Examples and Comparative Examples, a flat plate measuring 60 mm x 60 mm x 2 mm was injection molded to prepare a test specimen. The relative dielectric constant of each test specimen was measured at a frequency of 1 MHz in accordance with IEC 62631-2-1. Measuring device: Precision LCR meter E4980A manufactured by Agilent Technologies, Inc.

[0130] <In-plane thermal conductivity> For each of the examples and comparative examples, a flat plate measuring 60 mm x 60 mm x 2 mm was injection molded to prepare a test specimen. The in-plane thermal conductivity of each test specimen was measured using the following device. Measuring device: Hot disk method thermal property measuring device TPA-501 manufactured by Kyoto Electronics Manufacturing Co., Ltd.

[0131] <Thickness Thermal Conductivity> For each of the Examples and Comparative Examples, a 35 mm x 35 mm x 0.8 mmt flat plate was injection molded to prepare a test specimen. The thermal conductivity of each test specimen was calculated from the thermal diffusivity, specific heat capacity, and density. Specifically, the thermal conductivity was calculated by multiplying the thermal diffusivity by the specific heat capacity and density.

[0132] Thermal diffusivity The thermal diffusivity of each test piece was measured using the following equipment: Measurement equipment: Thermowave analyzer TA33, manufactured by Bethel Co., Ltd., a thermal property measurement device using a cyclic heating radiation thermometer.

[0133] Specific heat capacity The specific heat capacity of each test piece was measured using the following device. Measuring device: Mettler Toledo Differential Scanning Calorimeter DSC1, under nitrogen atmosphere, at a heating rate of 10°C / min, and the value at 25°C was used.

[0134] Density (underwater displacement method) was measured in accordance with JIS K7112:1999 underwater displacement method. Measuring device: SD-200L electronic hydrometer manufactured by Alpha Mirage Co., Ltd.

[0135] <Tensile Test> For each of the Examples and Comparative Examples, an ISO (1A) dumbbell was injection molded and subjected to measurement in accordance with JIS K7161-1, 2-1994. Measuring device: Strograph API II manufactured by Toyo Seiki Co., Ltd.

[0136] <Spiral Flow Length (SFL)> For each of the Examples and Comparative Examples, the spiral flow length was measured under the following conditions: Wall thickness: 1 mm Primary injection pressure: 100 MPa Injection speed: 100 mm / s (primary), 130 mm / s (secondary)

[0137] <Flame Retardancy> A vertical flame test was conducted in accordance with the UL-94V standard using a flame retardancy evaluation tester (HVUL2 UL combustion test chamber manufactured by ATLAS). Specifically, five test specimens were ranked for flammability in accordance with the UL-94V standard based on the first and second burning times, whether the cotton ignited, etc.

[0138] [Results] The results are shown in Tables 1 to 3. In Tables 1 to 3, "thermal conductive filler proportion" represents the proportion calculated by the following formula: Thermal conductive filler proportion (vol %) = total volume of thermal conductive filler / (total volume of thermal conductive filler + total volume of base resin) In Tables 1 to 3, a blank in the blending amount column indicates that the component was not added, and "-" in the evaluation results indicates that the measurement was not performed.

[0139]

[0140]

[0141]

[0142] Comparing Examples 2 and 4 with Comparative Example 1, it was found that the incorporation of a thermally conductive filler increased the thermal conductivity in the thickness direction by three times. Furthermore, because thermally conductive fillers typically have a higher dielectric constant than resins, adding a thermally conductive filler increases the dielectric constant of the resin composition. However, by incorporating NE-GF, it was possible to suppress the increase in the dielectric constant. Comparing Example 8 with Comparative Example 2, it was found that the combined use of thermally conductive fillers (A) and (B) increased the thermal conductivity in the thickness direction by two times.

[0143] Comparing Example 1 with Examples 12 and 13, it was found that the dielectric constant could be further reduced by adding PTFE.

[0144] Comparing Examples 1 and 2 with Examples 3 and 4, it was found that the use of LCP as the base resin improved molding flowability. By using a resin composition with improved molding flowability in this way, thin-wall molding becomes possible.

[0145] The above results demonstrate that a resin composition comprising a base resin that is at least one selected from the group consisting of liquid crystal resins and polyphenylene sulfide resins, and a thermally conductive filler, wherein the thermally conductive filler comprises a filler (A) having an isotropic shape and a filler (B) having an anisotropic shape, has high thermal conductivity in the thickness direction.

[0146] The resin composition according to one aspect of the present invention can be suitably used as a resin composition for a coating material or a resin composition for an insulating material.

Claims

1. A resin composition comprising: a base resin which is at least one type selected from the group consisting of liquid crystal resins and polyphenylene sulfide resins; and a thermally conductive filler, the thermally conductive filler comprising filler (A) having an isotropic shape and filler (B) having a scaly or plate-like anisotropic shape.

2. The resin composition described in claim 1, wherein the filler (A) having an isotropic shape is at least one selected from the group consisting of magnesite, magnesium oxide, granular boehmite, and granular graphite, and the filler (B) having a scaly or plate-like anisotropic shape is at least one selected from the group consisting of scaly or plate-like talc, scaly or plate-like boehmite, and scaly or plate-like graphite.

3. A resin composition described in claim 1 or 2, wherein the aspect ratio of the filler (A) having an isotropic shape is 1.0 or more and less than 3.0, and the aspect ratio of the filler (B) having a scale-like or plate-like anisotropic shape is 3 or more and 200 or less.

4. A resin composition according to any one of claims 1 to 3, wherein the filler (A) having an isotropic shape is magnesite.

5. A resin composition according to any one of claims 1 to 3, wherein the filler (B) having a scaly or plate-like anisotropic shape is scaly or plate-like talc.

6. A resin composition according to any one of claims 1 to 5, wherein the content of the thermally conductive filler in the resin composition is 25 mass % or more and 55 mass % or less.

7. A resin composition described in any one of claims 1 to 6, wherein the ratio of the content of the filler (A) having an isotropic shape to the content of the filler (B) having a scale-like or plate-like anisotropic shape is 10:90 or more and 80:20 or less in volume ratio.

8. The resin composition according to any one of claims 1 to 7, further comprising a fibrous filler.

9. The resin composition according to claim 8, wherein the fibrous filler is glass fiber.

10. The resin composition according to claim 9, wherein the glass fibers have a relative dielectric constant of 5.5 or less when measured at 1 GHz.

11. The resin composition according to any one of claims 1 to 10, further comprising a fluororesin.

12. The resin composition according to any one of claims 1 to 11, which is a resin composition for use as a coating material or an insulating material.

13. A coating material or insulating material comprising the resin composition according to any one of claims 1 to 12.

14. A molded article comprising the resin composition according to any one of claims 1 to 12.

15. A covering or insulating part made of the covering or insulating material according to claim 13.

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