Resin composition and molded article

Abstract

To provide a resin composition capable of suppressing the occurrence of a gap in a hole part when inserted into the hole part of a laminated core.SOLUTION: A resin composition used for insertion into a hole of a laminated core, comprising an epoxy resin (A) and soft magnetic particles (B), wherein the resin composition has a spiral flow at 175 °C. of 10 cm or more and 200 cm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a resin composition and a molded article. [Background technology]

[0002] A laminated core, in which a plurality of plate members are stacked, is known as a core for a rotating electrical machine such as a motor. As a method for fastening the stacked plate members to each other, in addition to caulking and welding, a method for fastening using a resin material is also known.

[0003] Patent Document 1 describes an electric motor stator having a laminated structure of electromagnetic steel sheets, with the objective of providing a technology for achieving a laminated structure without using dowel lamination (caulking lamination) or adhesive lamination. The electric motor stator is described as being formed by laminating multiple electromagnetic steel sheets, and has an annular yoke portion, multiple teeth extending from the yoke portion in the motor axial direction, and a first fixing portion that integrally wraps around and covers the peripheries of the teeth portions with a resin composition to tightly fix the multiple electromagnetic steel sheets in the teeth portion. The document further describes that the yoke portion has through holes that penetrate in the lamination direction, and a second fixing portion that fills the through holes with a resin composition to tightly fix the multiple electromagnetic steel sheets in the yoke portion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-092163 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention provides a resin composition that can suppress the occurrence of gaps in holes when inserted into holes in a laminated core. [Means for solving the problem]

[0006] According to the inventors' investigations, when a resin composition is inserted into a hole in a laminated core, there is a risk of gaps occurring within the hole. As a result of further intensive investigations, the inventors have found that the occurrence of gaps within the hole can be suppressed by setting the spiral flow at 175°C within a predetermined range in a resin composition containing an epoxy resin and soft magnetic particles, and have completed the present invention.

[0007] That is, according to the present invention, there are provided the following resin compositions and molded articles.

[0008] [1] A resin composition used to insert into a hole of a laminated core, an epoxy resin (A); soft magnetic particles (B); Including, A resin composition having a spiral flow at 175°C of 10 cm or more and 200 cm or less. [2] The resin composition according to [1], wherein the epoxy resin (A) comprises at least one selected from the group consisting of aryl alkylene type epoxy resins, novolac type epoxy resins, triphenylmethane type epoxy resins, bisphenol type epoxy resins, biphenyl type epoxy resins, naphthalene type epoxy resins, anthracene type epoxy resins, phenoxy type epoxy resins, dicyclopentadiene type epoxy resins, norbornene type epoxy resins, adamantane type epoxy resins, fluorene type epoxy resins, and Xyloc type epoxy resins. [3] The resin composition according to [1] or [2], wherein the epoxy resin (A) is solid at 25°C. [4] The resin composition according to any one of [1] to [3], wherein the content of the epoxy resin (A) in the resin composition is more than 0 mass% and 10.00 mass% or less, when the entire resin composition is taken as 100 mass%. [5] The resin composition according to any one of [1] to [4], wherein the content of the soft magnetic particles (B) in the resin composition is 50% by volume or more and 90% by volume or less, when the entire resin composition is taken as 100% by volume. [6] The resin composition according to any one of [1] to [5], wherein the soft magnetic particles (B) contain Si elements. [7] The resin composition according to any one of [1] to [6], wherein the soft magnetic particles (B) contain crystalline particles. [8] The resin composition according to any one of [1] to [7], wherein the soft magnetic particles (B) include amorphous particles. [9] The resin composition according to any one of [1] to [8], wherein the soft magnetic particles (B) contain gas-water atomized powder.

[10] The resin composition according to any one of [1] to [9], further comprising a phenol-based curing agent (C).

[11] Further comprising a curing catalyst (D), The resin composition according to any one of [1] to

[10] , wherein the curing catalyst (D) includes at least one selected from the group consisting of a tetra-substituted phosphonium compound, a phosphobetaine compound, an adduct of a phosphine compound and a quinone compound, and an adduct of a phosphonium compound and a silane compound.

[12] The resin composition according to any one of [1] to

[11] , further comprising a silica filler (E).

[13] The resin composition according to any one of [1] to

[12] , which has a gel time at 175°C of 30 seconds or more and 300 seconds or less.

[14] The resin composition according to any one of [1] to

[13] , wherein a cured product of the resin composition has a relative magnetic permeability at 25° C. of 30 or more.

[15] The resin composition according to any one of [1] to

[14] , wherein a cured product of the resin composition has a saturation magnetic flux density at 25° C. of 0.2 T or more.

[16] The resin composition according to any one of [1] to

[15] , wherein a coefficient of linear expansion (CTE1) of a cured product of the resin composition in the range from 25°C to the glass transition temperature of the cured product is 30 ppm / °C or less.

[17] The resin composition according to any one of [1] to

[16] , wherein a coefficient of linear expansion (CTE2) of a cured product of the resin composition in the range from the glass transition temperature of the cured product to 320°C is 100 ppm / °C or less.

[18] The resin composition according to any one of [1] to

[17] , wherein a cured product of the resin composition has a flexural strength of 50 MPa or more and 200 MPa or less at 25°C as measured in accordance with JIS K 6911:2006.

[19] The resin composition according to any one of [1] to

[18] , wherein a cured product of the resin composition has a flexural modulus at 25°C of 20,000 MPa or more and 50,000 MPa or less, as measured in accordance with JIS K 6911:2006.

[20] The resin composition according to any one of [1] to

[19] , wherein a cured product of the resin composition has a glass transition temperature of 100°C or higher and 250°C or lower. [twenty one] The resin composition according to any one of [1] to

[20] , which is solid at 25°C. [twenty two] The resin composition according to any one of [1] to

[21] , which is in a tablet form at 25°C. [twenty three] The resin composition according to any one of [1] to

[22] , wherein the resin composition is inserted into the hole by transfer molding. [twenty four] A molded article obtained by curing the resin composition according to any one of [1] to

[23] . [twenty five] The molded article according to

[24] , which is a transfer molded article. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a resin composition that can suppress the occurrence of gaps in the hole when inserted into the hole of a laminated core. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a schematic perspective view showing an example of a stator core according to the present embodiment. [Figure 2] FIG. 2 is a schematic plan view of the stator core in the lamination direction according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all drawings, similar components are given the same reference numerals and their explanations will be omitted as appropriate. The drawings are schematic diagrams and do not correspond to the actual dimensional ratios. In this specification, "A to B" indicating a numerical range means A or more and B or less unless otherwise specified.

[0012] The resin composition of this embodiment is a resin composition used to insert into the hole of a laminated core, and contains an epoxy resin (A) and soft magnetic particles (B), and has a spiral flow at 175°C of 10 cm or more and 200 cm or less.

[0013] The spiral flow of the resin composition of this embodiment at 175°C is 10 cm or more and 200 cm or less, preferably 20 cm or more and 180 cm or less, more preferably 30 cm or more and 160 cm or less, even more preferably 35 cm or more and 140 cm or less, even more preferably 40 cm or more and 120 cm or less, and even more preferably 45 cm or more and 100 cm or less.

[0014] According to the inventors' investigations, when a resin composition is inserted into a hole in a laminated core, there is a risk of gaps being generated within the hole. As a result of further intensive investigations, the inventors have found that the generation of gaps within the hole can be suppressed by setting the spiral flow at 175°C within a predetermined range in a resin composition containing an epoxy resin and soft magnetic particles.

[0015] By setting the spiral flow at 175°C to the above lower limit or more, the fluidity of the molten resin composition can be improved, which can prevent gaps from forming in the hole when the resin composition is inserted into the hole of a laminated core. Furthermore, by setting the spiral flow at 175°C to the above upper limit or less, the handleability of the resin composition can be improved.

[0016] The spiral flow of a resin composition at 175°C is measured by the following method. Using a low-pressure transfer molding machine, the resin composition is injected into a spiral flow measurement mold in accordance with ANSI / ASTM D 3123-72, and the spiral flow (flow length) is measured. The measurement conditions are a mold temperature of 175°C, an injection pressure of 6.9 MPa, and a pressure dwell time of 120 seconds.

[0017] In this embodiment, for example, by controlling the following production conditions, the spiral flow at 175° C. can be set within the above range. (1) Type and content of epoxy resin (A) (2) Type and content of soft magnetic particles (B) (3) Use of silica filler (E), type, median diameter, and content of silica filler (E)

[0018] Hereinafter, each component contained in the resin composition of the present embodiment will be described.

[0019] (Epoxy resin (A)) The resin composition of the present embodiment contains an epoxy resin (A).

[0020] The epoxy resin (A) is, for example, aryl alkylene epoxy resins such as biphenyl aralkyl epoxy resins and xylylene epoxy resins; Novolac epoxy resins such as phenol novolac epoxy resins, cresol novolac epoxy resins, trisphenol methane novolac epoxy resins, tetrakisphenol ethane novolac epoxy resins, and novolac epoxy resins having a condensed ring aromatic hydrocarbon structure; Triphenylmethane type epoxy resin; Bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, tetramethylbisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol E type epoxy resin, bisphenol M type epoxy resin, bisphenol P type epoxy resin, and bisphenol Z type epoxy resin; Biphenyl type epoxy resin; naphthalene-type epoxy resins such as naphthylene ether-type epoxy resins, naphthol-type epoxy resins, naphthalenediol-type epoxy resins, difunctional or tetrafunctional epoxy-type naphthalene resins, binaphthyl-type epoxy resins, and naphthalene aralkyl-type epoxy resins; Anthracene-type epoxy resins; Phenoxy-type epoxy resin; Dicyclopentadiene type epoxy resin; Norbornene-type epoxy resins; Adamantane-type epoxy resin; fluorene-type epoxy resin; and The epoxy resin contains at least one selected from the group consisting of Xylok type epoxy resins.

[0021] The epoxy resin (A) preferably comprises at least one selected from the group consisting of aryl alkylene epoxy resins, novolac epoxy resins, triphenylmethane epoxy resins, bisphenol epoxy resins, biphenyl epoxy resins, and Xylok epoxy resins, more preferably at least one selected from the group consisting of biphenyl aralkyl epoxy resins, cresol novolac epoxy resins, triphenylmethane epoxy resins, bisphenol A epoxy resins, biphenyl epoxy resins, and Xylok epoxy resins, even more preferably at least one selected from the group consisting of biphenyl aralkyl epoxy resins, cresol novolac epoxy resins, and triphenylmethane epoxy resins, and even more preferably a biphenyl aralkyl epoxy resin. This improves the fluidity of the molten resin composition, thereby further suppressing the formation of gaps in the holes of a laminated core when the resin composition is inserted into the holes.

[0022] The epoxy resin (A) is preferably a solid at 25° C. This can improve the handleability of the epoxy resin (A).

[0023] The content of the epoxy resin (A) in the resin composition, when the entire resin composition is taken as 100% by mass, is preferably more than 0% by mass and 10.00% by mass or less, more preferably 0.25% by mass or more and 9.00% by mass or less, even more preferably 0.50% by mass or more and 8.00% by mass or less, even more preferably 1.00% by mass or more and 7.00% by mass or less, even more preferably 1.20% by mass or more and 6.00% by mass or less, even more preferably 1.40% by mass or more and 5.00% by mass or less, and even more preferably 1.60% by mass or more and 4.00% by mass or less. By setting the content of the epoxy resin (A) in the resin composition within this range, the fluidity of the molten resin composition can be further improved, and therefore, when the resin composition is inserted into a hole in a laminated core, the occurrence of gaps in the hole can be further suppressed.

[0024] (Soft magnetic particles (B)) The resin composition of this embodiment contains soft magnetic particles (B). Soft magnetic refers to ferromagnetism with a small coercive force. Generally, soft magnetic refers to ferromagnetism with a coercive force of 800 A / m or less.

[0025] The soft magnetic particles (B) may contain Fe element. The soft magnetic particles (B) may be, for example, iron-based particles containing iron as a main component, or may be an iron alloy containing iron as a main component. That is, the soft magnetic particles (B) may be, for example, iron-based particles having the highest iron content by mass in their chemical composition, or may be an iron alloy having the highest iron content by mass in their chemical composition.

[0026] The soft magnetic particles (B) may contain an element other than Fe. Specifically, the soft magnetic particles (B) may contain at least one element selected from the group consisting of B, C, N, O, Al, Si, P, S, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Cd, In, and Sn. The soft magnetic particles (B) preferably contain at least one element selected from the group consisting of Si, Ni, and Co, and more preferably contain Si. This can improve the relative permeability and saturation magnetic flux density of the cured resin composition.

[0027] The soft magnetic particles (B) may include crystalline particles or amorphous particles.

[0028] The soft magnetic particles (B) preferably contain gas-water atomized powder. The gas-water atomized powder can be prepared by an atomization method using a mixture of water and gas as a pressurized fluid. The gas-water atomized powder is a non-spherical atomized powder and is different from spherical atomized powder and irregularly shaped water atomized powder. The gas-water atomized powder has the high sphericity characteristic of gas atomized powder and the high strength of the compacted powder characteristic of water atomized powder. By including the gas-water atomized powder in the soft magnetic particles (B), the fluidity of the molten resin composition can be further improved, and therefore, when the resin composition is inserted into the holes of a laminated core, the occurrence of gaps in the holes can be further suppressed. Furthermore, the mechanical strength of the cured resin composition can be improved.

[0029] The soft magnetic particles (B) preferably contain large soft magnetic particles with a median diameter of 20 μm or more and 300 μm or less, and small soft magnetic particles with a median diameter of less than 20 μm, thereby improving the filling rate of the soft magnetic particles (B) in the resin composition and thereby improving the relative permeability and saturation magnetic flux density of the cured product of the resin composition.

[0030] The soft magnetic particles having a large particle size include soft magnetic particles having a median size of preferably 25 μm or more and 280 μm or less, more preferably 30 μm or more and 250 μm or less, even more preferably 35 μm or more and 200 μm or less, even more preferably 40 μm or more and 150 μm or less, and even more preferably 45 μm or more and 100 μm or less. This can improve the filling rate of the soft magnetic particles (B) in the resin composition, and can improve the relative permeability and saturation magnetic flux density of the cured product of the resin composition.

[0031] The soft magnetic particles having a small particle size include soft magnetic particles having a median diameter of preferably 18 μm or less, more preferably 15 μm or less, and even more preferably 12 μm or less. This allows the filling rate of the soft magnetic particles (B) in the resin composition to be improved. The lower limit of the median diameter of the soft magnetic particles contained in the soft magnetic particles having a small particle size is not particularly limited, but may be, for example, 0.5 μm or more, or 1 μm or more.

[0032] The median diameter can be measured, for example, using a laser diffraction / scattering particle size distribution analyzer. Specifically, the soft magnetic particles (B) are measured in a wet state using a Shimadzu SALD-7500nano to obtain a particle size distribution curve measured on a volume basis, and the median diameter can be determined by analyzing this distribution curve.

[0033] The content of the soft magnetic particles (B) in the resin composition, when the total volume of the resin composition is taken as 100 volume %, is preferably 50 to 90 volume %, more preferably 55 to 88 volume %, even more preferably 60 to 87 volume %, even more preferably 65 to 86 volume %, and even more preferably 70 to 85 volume %. By setting the content of the soft magnetic particles (B) in the resin composition to the above lower limit or higher, the relative permeability and saturation magnetic flux density of the cured resin composition can be improved. Furthermore, by setting the content of the soft magnetic particles (B) in the resin composition to the above upper limit or lower, the fluidity of the molten resin composition can be further improved, and therefore, when the resin composition is inserted into the hole of a laminated core, the occurrence of gaps in the hole can be further suppressed.

[0034] The content of the soft magnetic particles (B) in the resin composition is preferably 85.00% by mass or more and 99.00% by mass or less, more preferably 88.00% by mass or more and 98.00% by mass or less, and even more preferably 90.00% by mass or more and 97.00% by mass or less, when the entire resin composition is taken as 100% by mass. By setting the content of the soft magnetic particles (B) in the resin composition to the above-mentioned lower limit or more, the relative permeability and saturation magnetic flux density of the cured product of the resin composition can be improved. Furthermore, by setting the content of the soft magnetic particles (B) in the resin composition to the above-mentioned upper limit or less, the fluidity of the molten resin composition can be further improved, and therefore, when the resin composition is inserted into the hole of a laminated core, the occurrence of gaps in the hole can be further suppressed.

[0035] (Phenol-based hardener (C)) The resin composition of this embodiment preferably further contains a phenolic curing agent (C), which can improve the durability of the cured product of the resin composition.

[0036] The phenol-based curing agent (C) preferably contains at least one selected from the group consisting of a biphenylene skeleton and a novolac skeleton, which can improve the durability of the cured product of the resin composition.

[0037] The phenolic curing agent (C) preferably contains at least one selected from the group consisting of biphenylaralkyl-type phenolic curing agents, novolak-type phenolic curing agents, and Zylok-type phenolic curing agents, and more preferably contains a biphenylaralkyl-type phenolic curing agent, which can improve the durability of the cured product of the resin composition.

[0038] The content of the phenolic curing agent (C) in the resin composition, when the entire resin composition is taken as 100 mass%, is preferably more than 0 mass% and 10.00 mass% or less, more preferably 0.10 mass% or more and 8.00 mass% or less, even more preferably 0.20 mass% or more and 6.00 mass% or less, even more preferably 0.50 mass% or more and 4.00 mass% or less, and even more preferably 0.80 mass% or more and 3.00 mass% or less. By setting the content of the phenolic curing agent (C) in the resin composition within the above range, the durability of the cured product of the resin composition can be improved.

[0039] (Curing catalyst (D)) The resin composition of the present embodiment preferably further contains a curing catalyst (D), which can shorten the time it takes for the resin composition to cure, thereby shortening the time required to produce a cured product of the resin composition.

[0040] The curing catalyst (D) is, for example, phosphorus atom-containing compounds such as tetra-substituted phosphonium compounds, phosphobetaine compounds, adducts of phosphine compounds and quinone compounds, adducts of phosphonium compounds and silane compounds, and organic phosphines; Imidazoles such as 2-methylimidazole and 2-phenylimidazole (imidazole curing accelerators); and The compound contains at least one member selected from the group consisting of nitrogen atom-containing compounds such as 1,8-diazabicyclo[5.4.0]undecene-7, amidines such as benzyldimethylamine, tertiary amines, and quaternary salts thereof.

[0041] The curing catalyst (D) preferably contains a phosphorus atom-containing compound, more preferably at least one selected from the group consisting of tetra-substituted phosphonium compounds, phosphobetaine compounds, adducts of phosphine compounds and quinone compounds, and adducts of phosphonium compounds and silane compounds. This allows the curing rate of the resin composition to be appropriately adjusted, thereby improving the moldability, handleability, and fillability of the resin composition. Furthermore, the mechanical strength of the cured product of the resin composition can be improved.

[0042] The content of the curing catalyst (D) in the resin composition, when the entire resin composition is taken as 100% by mass, is preferably more than 0% by mass and 1.00% by mass or less, more preferably 0.01% by mass or more and 0.80% by mass or less, even more preferably 0.02% by mass or more and 0.50% by mass or less, and even more preferably 0.05% by mass or more and 0.20% by mass or less. By setting the content of the curing catalyst (D) in the resin composition within the above range, the curing rate of the resin composition can be appropriately adjusted, and therefore the moldability, handleability, and fillability of the resin composition can be improved.

[0043] (Silica filler (E)) The resin composition of this embodiment preferably further contains a silica filler (E). This allows the melt viscosity of the resin composition to be appropriately adjusted, improving the flowability of the molten resin composition. Furthermore, the generation of burrs in the cured product of the resin composition can be suppressed.

[0044] The silica filler (E) preferably contains at least one selected from the group consisting of fused silica filler and crystalline silica filler, and more preferably contains fused silica filler. This allows the melt viscosity of the resin composition to be appropriately adjusted, improving the fluidity of the molten resin composition. It also prevents burrs from forming in the cured product of the resin composition.

[0045] The median diameter of the silica filler (E) is preferably 0.1 μm or more and 10.0 μm or less, more preferably 0.2 μm or more and 8.0 μm or less, and even more preferably 0.3 μm or more and 6.0 μm or less. By setting the median diameter of the silica filler (E) within the above range, the melt viscosity of the resin composition can be appropriately adjusted, and the fluidity of the molten resin composition can be improved. Furthermore, the generation of burrs in the cured product of the resin composition can be suppressed.

[0046] The median diameter of the silica filler (E) means the median diameter obtained from a particle size distribution curve measured on a volume basis. The median diameter of the silica filler (E) can be measured, for example, using a laser diffraction particle size distribution analyzer.

[0047] The content of the silica filler (E) in the resin composition, when the entire resin composition is taken as 100% by mass, is preferably more than 0% by mass and not more than 5.00% by mass, more preferably 0.10% by mass to 4.00% by mass, even more preferably 0.20% by mass to 3.00% by mass, and even more preferably 0.25% by mass to 2.00% by mass. By setting the content of the silica filler (E) in the resin composition within the above range, the melt viscosity of the resin composition can be appropriately adjusted, improving the fluidity of the molten resin composition. Furthermore, the generation of burrs in the cured product of the resin composition can be suppressed.

[0048] (Other ingredients) From the viewpoint of improving the mechanical strength of the cured product of the resin composition, the resin composition of the present embodiment preferably further contains a coupling agent. As the coupling agent, a known coupling agent can be used. The coupling agent may include, for example, a silane coupling agent.

[0049] From the viewpoint of improving the mechanical strength of the cured resin composition, the content of the coupling agent in the resin composition of the present embodiment is preferably more than 0 mass% and 1.00 mass% or less, more preferably 0.05 mass% or more and 0.80 mass% or less, and even more preferably 0.10 mass% or more and 0.50 mass% or less, when the entire resin composition is taken as 100 mass%.

[0050] The resin composition of the present embodiment may further include a release agent. The release agent may include at least one selected from the group consisting of a copolymer of 1-alkene and maleic anhydride; a fatty acid-based release agent such as stearic acid, montanic acid, or behenic acid; a fatty acid metal soap-based release agent such as a metal stearate; carnauba wax; and polyethylene oxide, or may include at least one selected from the group consisting of a copolymer of 1-alkene and maleic anhydride, a fatty acid-based release agent, and carnauba wax, or may include at least one selected from the group consisting of a copolymer of 1-alkene and maleic anhydride, stearic acid, and carnauba wax.

[0051] The content of the release agent in the resin composition of the present embodiment is preferably more than 0% by mass and not more than 2.00% by mass, more preferably 0.01% by mass or more and 1.00% by mass or less, and even more preferably 0.05% by mass or more and 0.50% by mass or less, when the entire resin composition is taken as 100% by mass.

[0052] The resin composition of the present embodiment may further include an adhesion aid. Known adhesion aids can be used as the adhesion aid. The adhesion aid may include, for example, an azole-based compound.

[0053] The content of the adhesion aid in the resin composition of the present embodiment, when the entire resin composition is taken as 100% by mass, is preferably more than 0% by mass and 0.50% by mass or less, more preferably 0.01% by mass or more and 0.30% by mass or less, and even more preferably 0.02% by mass or more and 0.20% by mass or less.

[0054] The resin composition of the present embodiment may further include a stress reducing agent. The stress reducing agent may include, for example, at least one selected from the group consisting of silicone oil, silicone rubber, polybutadiene, and acrylonitrile butadiene copolymer, or may include silicone oil.

[0055] The content of the low stress agent in the resin composition of this embodiment is preferably more than 0 mass% and not more than 0.50 mass%, more preferably 0.01 mass% or more and 0.40 mass% or less, and even more preferably 0.02 mass% or more and 0.30 mass% or less, when the entire resin composition is taken as 100 mass%.

[0056] The resin composition of the present embodiment may further contain a colorant, a dye, a pigment, a dispersant, a corrosion-resistant agent, a flame retardant, and the like.

[0057] (Physical properties of resin composition) The physical properties of the resin composition of this embodiment will be described below.

[0058] The gel time of the resin composition of this embodiment at 175°C is preferably 30 to 300 seconds, more preferably 35 to 250 seconds, even more preferably 40 to 200 seconds, and even more preferably 45 to 150 seconds. By setting the gel time at 175°C to the above-mentioned lower limit or more, a certain amount of time until the resin composition cures can be ensured, thereby improving the moldability, handleability, and fillability of the resin composition. Furthermore, by setting the gel time at 175°C to the above-mentioned upper limit or less, the time until the resin composition cures can be shortened, thereby shortening the production time for a cured product of the resin composition.

[0059] The gel time of a resin composition at 175°C is measured by the following method: The resin composition is placed on a hot plate controlled at 175°C and kneaded with a spatula at one stroke per second. The time from when the resin composition is dissolved by heat until it hardens is measured and used as the gel time.

[0060] In this embodiment, for example, the gel time at 175° C. can be set within the above range by controlling the following production conditions. (1) Type and content of epoxy resin (A) (2) Type and content of soft magnetic particles (B) (3) Use of curing catalyst (D), type and content of curing catalyst (D) (4) Use of silica filler (E), type, median diameter, and content of silica filler (E)

[0061] The cured product of the resin composition of this embodiment has a relative magnetic permeability at 25°C of preferably 30 or more, more preferably 35 or more, even more preferably 40 or more, even more preferably 42 or more, and even more preferably 44 or more. By making the relative magnetic permeability at 25°C equal to or greater than the above-mentioned lower limit, the magnetic properties of the cured product of the resin composition can be improved. In particular, when the resin composition of this embodiment is used to insert into the hole of a laminated core, the flow of magnetic flux in the laminated core becomes smooth. This can improve the torque efficiency of a rotating electric machine. The laminated core will be described in detail later.

[0062] The upper limit of the relative magnetic permeability at 25° C. is not particularly limited, but may be, for example, 70 or less, 60 or less, or 50 or less.

[0063] The relative magnetic permeability at 25°C of a cured resin composition is measured using the following method. Using a low-pressure transfer molding machine, the resin composition is injection molded at a mold temperature of 175°C, an injection pressure of 9.8 MPa, and a dwell time of 120 seconds to obtain a disk-shaped molded body with a diameter of 50 mm and a thickness of 3 mm. The resulting molded body is then post-cured at 175°C for 4 hours. A router processing machine is then used to machine the molded body into a toroidal shape with an outer diameter of 27 mm and an inner diameter of 15 mm to prepare a test specimen. A 42-turn primary coil and a 42-turn secondary coil are wound around the test specimen, and AC measurements are performed using a DC / AC magnetization characteristic tester. The value at a frequency of 50 kHz and a magnetic flux density of 50 mT is taken as the relative magnetic permeability.

[0064] In this embodiment, for example, by controlling the type and content of the soft magnetic particles (B), the relative magnetic permeability at 25° C. can be set within the above range.

[0065] The saturation magnetic flux density at 25°C of the cured product of the resin composition of this embodiment is preferably 0.2 T or more, more preferably 0.4 T or more, even more preferably 0.6 T or more, even more preferably 0.8 T or more, and even more preferably 1.0 T or more. By making the saturation magnetic flux density at 25°C equal to or greater than the above lower limit, the magnetic properties of the cured product of the resin composition can be improved. In particular, when the resin composition of this embodiment is used to insert into the hole of a laminated core, the flow of magnetic flux in the laminated core becomes smooth. This can improve the torque efficiency of a rotating electrical machine. The laminated core will be described in detail later.

[0066] The upper limit of the saturation magnetic flux density at 25° C. is not particularly limited, but may be, for example, 3.0 T or less, 2.5 T or less, or 2.0 T or less.

[0067] The saturation magnetic flux density of a cured resin composition at 25°C is measured using the following method. Using a low-pressure transfer molding machine, the resin composition is injection molded at a mold temperature of 175°C, an injection pressure of 9.8 MPa, and a dwell time of 300 seconds to obtain a cylindrical molded body with a diameter of 16 mm and a height of 32 mm. The molded body is then post-cured at 175°C for 4 hours. The saturation magnetic flux density is then measured using a DC / AC magnetization characteristic tester at a temperature of 25°C and an external magnetic field of 100 kA / m.

[0068] In this embodiment, for example, by controlling the type and content of the soft magnetic particles (B), the saturation magnetic flux density at 25° C. can be set within the above range.

[0069] The glass transition temperature of the cured product of the resin composition of this embodiment is preferably 100° C. or higher, more preferably 110° C. or higher, even more preferably 120° C. or higher, and even more preferably 130° C. or higher. By adjusting the glass transition temperature of the cured product of the resin composition to be equal to or higher than the above lower limit, the high-temperature durability of the cured product of the resin composition can be improved.

[0070] The upper limit of the glass transition temperature is not particularly limited, but may be, for example, 300°C or lower, or 250°C or lower.

[0071] The coefficient of linear expansion (CTE1) of a cured product of the resin composition of this embodiment in the temperature range from 25°C to the glass transition temperature of the cured product of this embodiment is preferably 8 ppm / °C or more and 30 ppm / °C or less, more preferably 9 ppm / °C or more and 25 ppm / °C or less, and even more preferably 10 ppm / °C or more and 20 ppm / °C or less. By setting the coefficient of linear expansion (CTE1) to the above-mentioned lower limit or more, the coefficient of linear expansion of a cured product of the resin composition during thermal history can be reduced. Furthermore, by setting the coefficient of linear expansion (CTE1) to the above-mentioned upper limit or less, the residual stress of a cured product of the resin composition can be reduced.

[0072] The coefficient of linear expansion (CTE2) of a cured product of the resin composition of this embodiment in the range from the glass transition temperature of the cured product of this embodiment to 320°C is preferably 5 ppm / °C or more and 100 ppm / °C or less, more preferably 10 ppm / °C or more and 80 ppm / °C or less, and even more preferably 15 ppm / °C or more and 60 ppm / °C or less. By setting the coefficient of linear expansion (CTE2) to the above-mentioned lower limit or more, the coefficient of linear expansion of a cured product of the resin composition during thermal history can be reduced. Furthermore, by setting the coefficient of linear expansion (CTE2) to the above-mentioned upper limit or less, the residual stress of a cured product of the resin composition can be reduced.

[0073] The glass transition temperature, coefficient of linear expansion (CTE1), and coefficient of linear expansion (CTE2) of a cured product made from a resin composition are measured using the following method. Using a low-pressure transfer molding machine, the resin composition is injection molded under conditions of a mold temperature of 175°C, an injection pressure of 9.8 MPa, and a dwell time of 300 seconds to obtain a rectangular parallelepiped molded product measuring 10 mm in width, 1.5 mm in thickness, and 55 mm in length. The molded product is then post-cured in air at 175°C for 4 hours to obtain a cured product. Using a viscoelasticity measuring device, the glass transition temperature, coefficient of linear expansion (CTE1), and coefficient of linear expansion (CTE2) of the resulting cured product are measured under conditions of a measurement temperature range of 25°C to 320°C and a heating rate of 5°C / min.

[0074] In this embodiment, for example, by controlling the type and content of the epoxy resin (A), the glass transition temperature, the coefficient of linear expansion (CTE1), and the coefficient of linear expansion (CTE2) of the cured product made of the resin composition can be set within the above ranges.

[0075] The flexural strength at 25°C of a cured product of the resin composition of this embodiment, measured in accordance with JIS K 6911:2006, is preferably 50 MPa or more, more preferably 70 MPa or more, and even more preferably 90 MPa or more. By ensuring that the flexural strength at 25°C is equal to or greater than the above lower limit, the mechanical strength of the cured product of the resin composition can be improved. Furthermore, when the resin composition of this embodiment is inserted into a hole in a laminated core, the mechanical strength of the laminated core can be improved.

[0076] The upper limit of the bending strength at 25° C. is not particularly limited, but may be, for example, 200 MPa or less, 170 MPa or less, or 150 MPa or less.

[0077] The flexural modulus at 25°C of a cured product of the resin composition of this embodiment, measured in accordance with JIS K 6911:2006, is preferably 20,000 MPa or more, more preferably 25,000 MPa or more, and even more preferably 27,000 MPa or more. By ensuring that the flexural modulus at 25°C is equal to or greater than the above lower limit, the mechanical strength of the cured product of the resin composition can be improved. Furthermore, when the resin composition of this embodiment is inserted into a hole in a laminated core, the mechanical strength of the laminated core can be improved.

[0078] The upper limit of the flexural modulus at 25° C. is not particularly limited, but may be, for example, 50,000 MPa or less, or 48,000 MPa or less.

[0079] The flexural strength and flexural modulus of a cured product of a resin composition at 25°C, measured in accordance with JIS K 6911:2006, are measured as follows. Using a low-pressure transfer molding machine, the resin composition is injection molded at a mold temperature of 175°C, an injection pressure of 9.8 MPa, and a dwell time of 300 seconds to obtain a rectangular parallelepiped molded product measuring 10 mm in width, 4 mm in thickness, and 80 mm in length. The molded product is then post-cured in air at 175°C for 4 hours to obtain a cured product. The flexural strength and flexural modulus of the resulting cured product are measured in accordance with JIS K 6911:2006 at a temperature of 25°C and a loading rate of 2 mm / min.

[0080] From the viewpoint of improving the storage properties and handling properties of the resin composition, the resin composition of the present embodiment is preferably solid at 25°C.

[0081] From the viewpoint of improving the storage and handling properties of the resin composition, the resin composition of the present embodiment is preferably in the form of a tablet at 25°C.

[0082] (Method of producing resin composition) The method for producing a resin composition according to the present embodiment includes, for example, (1) a step of mixing the components using a mixer to obtain a mixture, (2) a step of kneading the mixture using a roll to obtain a kneaded product, (3) a step of cooling the kneaded product, and (4) a step of pulverizing the cooled kneaded product. This results in a powdered resin composition. In the step of obtaining the kneaded product, the kneading temperature is preferably about 90°C. The kneading time is preferably 5 minutes or longer, more preferably 10 minutes or longer.

[0083] Furthermore, by tableting the obtained powdery resin composition, a tablet-shaped resin composition at 25°C can be obtained.

[0084] (Molded body and method for manufacturing the molded body) The resin composition of the present embodiment can be melted and cured to obtain a molded article. That is, the molded article of the present embodiment is a molded article obtained by curing the resin composition of the present embodiment.

[0085] The molded article of this embodiment is preferably a transfer molded article. Here, the transfer molded article refers to a molded article obtained by curing a melt of a resin composition using a transfer molding device. Note that the transfer molded article also includes a molded article obtained by further post-curing the above-mentioned molded article.

[0086] The method for producing the molded article of the present embodiment is not particularly limited, but examples thereof include a method in which the resin composition of the present embodiment is transfer molded using a known transfer molding device. Specifically, the resin composition of the present embodiment is preheated to melt, and the melt is injected into a mold with a plunger and held therein to harden the melt.

[0087] The conditions for transfer molding are not particularly limited, but for example, the preheating temperature is 60°C to 100°C, the mold temperature is 100°C to 200°C, and the pressure when injecting the molten resin composition into the mold is 0.5 MPa to 5.0 MPa. The temperature at which the resin composition is melted can be considered to be the same as the mold temperature.

[0088] When the molded article is post-cured, the molded article can be post-cured, for example, by heating it in the atmosphere at 175° C. for 4 hours.

[0089] (Stator core and manufacturing method of stator core) The resin composition of this embodiment is a resin composition used to be inserted into the hole of a laminated core. In particular, the resin composition of this embodiment is suitably used to be inserted into the hole of a stator core. Hereinafter, a stator core 100 of this embodiment will be described with reference to FIGS. 1 and 2.

[0090] 1 is a schematic perspective view showing an example of a stator core according to this embodiment. The stator core is one of the components of a stator. The stator is also one of the components of a rotating electrical machine (for example, a motor or a generator).

[0091] 1, the stator core 100 of this embodiment is a laminated core. That is, the stator core 100 of this embodiment includes a plurality of plate members 10. The plurality of plate members 10 are stacked in the axial direction of the stator core 100. The plate members 10 may be, for example, electromagnetic steel plates, permendur plates, amorphous metal plates, etc.

[0092] Fig. 2 is a schematic plan view of the stator core 100 of this embodiment in the stacking direction. As shown in Fig. 2, the stator core 100 of this embodiment includes a yoke 11 extending along the circumferential direction of the stator core 100, and teeth 13 extending from the yoke 11 toward the inside in the radial direction of the stator core 100. The yoke 11 has an annular structure when viewed from above in the stacking direction of the stator core 100. The yoke 11 and the teeth 13 may be integral or separate.

[0093] In this embodiment, a plurality of teeth 13 are provided along the circumferential direction of the stator core 100. A rotor (not shown) is housed radially inward of the teeth 13 in the stator core 100. Furthermore, slots 50 are defined between the plurality of teeth 13 in the circumferential direction of the stator core 100. That is, the slots 50 are spaces defined by the yoke 11, the plurality of teeth 13, and the rotor. A coil (not shown) is housed in the slots 50.

[0094] In this embodiment, the stator core 100 has at least one hole 30. The hole 30 is a hole that is open to at least one side. The hole 30 may be a hole that is open to both sides (i.e., a through hole). The hole 30 may be a hole that extends along the lamination direction of the stator core 100. The hole 30 may be a through hole that is open in the lamination direction of the stator core 100.

[0095] 2, from the viewpoint of improving the strength of the stator core 100, it is preferable that the holes 30 be defined in the yoke 11. In particular, from the viewpoint of improving the strength of the stator core 100, it is preferable that the holes 30 be defined in the yoke 11 and radially outward from the teeth 13.

[0096] The shape of the hole 30 in plan view in the stacking direction may be, for example, circular, rectangular, etc. From the viewpoint of suppressing stress concentration and improving the strength of the stator core 100, the shape of the hole 30 in plan view in the stacking direction is preferably circular.

[0097] A molded body obtained by curing the resin composition of the present embodiment is housed in the hole portion 30 of the stator core 100. That is, the stator core 100 includes a molded body obtained by curing the resin composition of the present embodiment housed in the hole portion 30.

[0098] By placing a molded body obtained by hardening the resin composition of this embodiment in the hole portion 30, multiple plate members 10 stacked in the axial direction of the stator core 100 can be fixed in the circumferential and radial directions of the stator core 100.

[0099] Furthermore, when stator core 100 is used in a rotating electric machine, magnetic flux flows from teeth 13 toward yoke 11 as a rotor housed radially inside stator core 100 rotates. If the cured product made from the resin composition of this embodiment has a relative permeability at 25°C equal to or greater than a predetermined value, magnetic flux can flow smoothly even in hole 30, which houses a molded product obtained by curing the resin composition, thereby improving the torque efficiency of the rotating electric machine. Similarly, if the cured product made from the resin composition of this embodiment has a saturation magnetic flux density at 25°C equal to or greater than a predetermined value, magnetic flux can flow smoothly even in hole 30, which houses a molded product obtained by curing the resin composition, thereby improving the torque efficiency of the rotating electric machine.

[0100] The method for manufacturing the stator core 100 of this embodiment is not particularly limited, but an example thereof is a method in which a known transfer molding device is used to transfer mold the resin composition of this embodiment into the hole 30 of the stator core 100. Specifically, an example is a method in which a preheated resin composition is injected into the hole 30 of the stator core 100 using a plunger and then cured. The preferred conditions for transfer molding the resin composition are the same as those for the above-mentioned method for producing a molded article.

[0101] The resin composition of this embodiment may be a resin composition that is inserted into the hole of a laminated core by transfer molding, or may be a resin composition that is inserted into the hole of a stator core by transfer molding.

[0102] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations may be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention. [Example]

[0103] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the descriptions of these examples.

[0104] (1) Raw materials The raw materials used in each example and comparative example are shown below.

[0105] (Epoxy resin (A)) a1: Biphenyl aralkyl epoxy resin (Nippon Kayaku Co., Ltd. "NC-3000L", solid at 25°C) a2: Cresol novolac epoxy resin (CNE195LL manufactured by Changchun Plastics Co., Ltd., solid at 25°C)

[0106] (Soft magnetic particles (B)) b1: Amorphous magnetic powder (Epson Atmix "KUAMET6B2 053C03", median diameter: 23 μm, Fe content: 87.6 mass%, Si content: 6.8 mass%) b2: Crystalline magnetic powder (Daido Steel Co., Ltd. "DAPMS3-100", gas-water atomized powder, median diameter: 70 μm, Fe content: 96.7 mass%, Si content: 3.0 mass%) b3: Crystalline magnetic powder (Epson Atmix "Fe-3.5Si-4.5Cr_PF-20F", median diameter: 10 μm, Fe content: 91.9 mass%, Si content: 3.5 mass%) b4: Amorphous magnetic powder (Epson Atmix "AW2-08_PF-3F", median diameter: 3 μm, Fe content: 87.4 mass%, Si content: 6.8 mass%) b5: Crystalline magnetic powder ("FSC-2" manufactured by Shinto Kogyo Co., Ltd., median diameter: 2 μm, Fe content: 91.1 mass%, Si content: 3.5 mass%)

[0107] (Phenol-based hardener (C)) c1: Phenol aralkyl resin containing biphenylene skeleton ("MEH-7851SS" manufactured by Meiwa Kasei Co., Ltd.) c2: Phenol novolac type phenolic hardener (Sumitomo Bakelite Co., Ltd. "PR-HF-3")

[0108] (Curing catalyst (D)) d1: Tetraphenylphosphonium bis(naphthalene-2,3-dioxy)phenylsilicate (Sumitomo Bakelite Co., Ltd.) d2: Tetraphenylphosphonium 4,4'-sulfonyldiphenolate (Sumitomo Bakelite Co., Ltd.) d3: Triphenylphosphine (manufactured by Hokko Chemical Co., Ltd.)

[0109] (Silica filler (E)) e1: Fused silica (median diameter 0.5 μm) e2: Fused crushed silica (Fumitec "FMT-15C", median diameter 5 μm)

[0110] (coupling agent) Phenylaminopropyltrimethoxysilane (Toray Dow Corning "CF-4083")

[0111] (mold release agent) Release agent 1: Synthetic wax (copolymer of 1-alkene and maleic anhydride) Release agent 2: Stearic acid (NOF Corporation "Powdered Stearic Acid Sakura Powder") Release agent 3: Carnauba wax (TOWAX-132, manufactured by Toa Kasei Co., Ltd.)

[0112] (adhesion aid) Compounds containing benzotriazole compounds (ADEKA "ADEKA STAB CDA-1M")

[0113] (low stress agent) Silicone oil (Toray Dow Corning "FZ-3730")

[0114] (coloring agent) Carbon #5 (Mitsubishi Chemical)

[0115] (2) Preparation of resin composition Each raw material was prepared according to the composition shown in Table 1. First, the soft magnetic particles (B) were mixed, and then the other components were added and mixed to obtain a mixture. The resulting mixture was then kneaded for 10 minutes at 100° C. The resulting kneaded product was cooled to room temperature to solidify, and then pulverized and tableted to obtain a tablet-shaped resin composition. In Examples 1 and 2 and Comparative Example 1, the resulting resin compositions were solid at 25°C. The content [volume %] of the soft magnetic particles (B) relative to the total resin composition was calculated based on the volume of the obtained resin composition and the volume of the soft magnetic particles (B) calculated from the density and content of the soft magnetic particles (B) in the resin composition.

[0116] (3) Evaluation of resin composition (Spiral Flow) Using a low-pressure transfer molding machine (Kotaki Seiki Co., Ltd., "KTS-30"), the resin composition was injected into a spiral flow measurement mold in accordance with ANSI / ASTM D 3123-72, and the spiral flow (flow length) was measured. The measurement conditions were a mold temperature of 175°C, an injection pressure of 6.9 MPa, and a pressure dwell time of 120 seconds. A larger spiral flow indicates better fluidity.

[0117] (Gel time) The resin composition was placed on a hot plate controlled at 175°C and kneaded with a spatula at one stroke per second. The time from when the resin composition was dissolved by heat until it hardened was measured and used as the gel time. The shorter the gel time, the faster the resin composition hardens.

[0118] (relative permeability) The resin composition was injected into a low-pressure transfer molding machine (Kotaki Seiki KTS-30) at a mold temperature of 175°C, an injection pressure of 9.8 MPa, and a dwell time of 120 seconds to obtain a disk-shaped molded body with a diameter of 50 mm and a thickness of 3 mm. The molded body was then post-cured at 175°C for 4 hours. The molded body was then processed into a toroidal shape with an outer diameter of 27 mm and an inner diameter of 15 mm using a router to prepare a test specimen. A 42-turn primary coil and a 42-turn secondary coil were wound around the test specimen, and AC measurements were performed using a DC / AC magnetization characteristic tester (Metron Giken MTR-1488). The value at a frequency of 50 kHz and a magnetic flux density of 50 mT was taken as the relative permeability.

[0119] (saturation magnetic flux density) The resin composition was injected into a low-pressure transfer molding machine (Kotaki Seiki KTS-30) at a mold temperature of 175°C, an injection pressure of 9.8 MPa, and a dwell time of 300 seconds to obtain a cylindrical molded body with a diameter of 16 mm and a height of 32 mm. The molded body was then post-cured at 175°C for 4 hours. The saturation magnetic flux density was then measured using a DC / AC magnetization characteristic tester (Metron Giken MTR-3368) at a temperature of 25°C and an external magnetic field of 100 kA / m.

[0120] (iron loss) Using a low-pressure transfer molding machine (Kotaki Seiki KTS-30), the resin composition was injected and molded under the conditions of a mold temperature of 175°C, an injection pressure of 9.8 MPa, and a holding pressure time of 120 seconds, to obtain a ring-shaped molded body with an outer diameter of 27 mm, an inner diameter of 15 mm, and a thickness of 3 mm. The obtained molded body was then post-cured at 175°C for 4 hours. Thereafter, the hysteresis loss Wh [kW / m] was measured using a BH curve tracer under the conditions of an excitation magnetic flux density Bm of 50 mT and a measurement frequency of 50 kHz. 3 ] and eddy current loss We [kW / m 3 The iron loss was calculated from the total value of the hysteresis loss Wh and the eddy current loss We.

[0121] (glass transition temperature and linear expansion coefficient) The resin composition was injected into a low-pressure transfer molding machine (Kotaki Seiki KTS-30) at a mold temperature of 175°C, an injection pressure of 9.8 MPa, and a holding time of 300 seconds to obtain a rectangular molded article measuring 10 mm in width, 1.5 mm in thickness, and 55 mm in length. The molded article was then post-cured in air at 175°C for 4 hours to obtain a cured product. Using a viscoelasticity measuring device (Hitachi High-Technologies Corporation, "DMA7100"), the glass transition temperature of the obtained cured product, the coefficient of linear expansion (CTE1) in the range from 25°C to the glass transition temperature of the cured product, and the coefficient of linear expansion (CTE2) in the range from the glass transition temperature to 320°C were measured under the conditions of a measurement temperature range of 25°C to 320°C and a heating rate of 5°C / min.

[0122] (Flexural strength and flexural modulus) The resin composition was injected into a low-pressure transfer molding machine (Kotaki Seiki KTS-30) at a mold temperature of 175°C, an injection pressure of 9.8 MPa, and a holding pressure of 300 seconds to obtain a rectangular molded article measuring 10 mm in width, 4 mm in thickness, and 80 mm in length. The molded article was then post-cured in air at 175°C for 4 hours to obtain a cured product. The flexural strength and flexural modulus of the resulting cured product were measured at a temperature of 25°C and a loading rate of 2 mm / min in accordance with JIS K 6911:2006.

[0123] The evaluation results for each of the examples and comparative examples are shown in Table 1.

[0124] [Table 1]

[0125] The saturation magnetic flux density was not measured for Comparative Example 1. Since the resin composition of Comparative Example 1 does not contain soft magnetic particles (B), the saturation magnetic flux density is considered to be 0T.

[0126] In Comparative Example 1, the resin composition did not contain soft magnetic particles (B) and was not excited, so that the iron loss could not be measured. [Explanation of symbols]

[0127] 10 Plate members 11 York 13 Teeth 30 Hole 50 slots 100 stator core

Claims

1. A resin composition used to insert into a hole of a laminated core, an epoxy resin (A); Soft magnetic particles (B), Including, A resin composition having a spiral flow at 175°C of 10 cm or more and 200 cm or less.

2. 2. The resin composition according to claim 1, wherein the epoxy resin (A) comprises at least one selected from the group consisting of aryl alkylene epoxy resins, novolac epoxy resins, triphenylmethane epoxy resins, bisphenol epoxy resins, biphenyl epoxy resins, naphthalene epoxy resins, anthracene epoxy resins, phenoxy epoxy resins, dicyclopentadiene epoxy resins, norbornene epoxy resins, adamantane epoxy resins, fluorene epoxy resins, and Xyloc epoxy resins.

3. The resin composition according to claim 1 or 2, wherein the epoxy resin (A) is solid at 25°C.

4. 3. The resin composition according to claim 1, wherein the content of the epoxy resin (A) in the resin composition is more than 0% by mass and 10.00% by mass or less, when the entire resin composition is 100% by mass.

5. 3. The resin composition according to claim 1, wherein the content of the soft magnetic particles (B) in the resin composition is 50% by volume or more and 90% by volume or less, when the entire resin composition is 100% by volume.

6. The resin composition according to claim 1 or 2, wherein the soft magnetic particles (B) contain Si elements.

7. The resin composition according to claim 1 or 2, wherein the soft magnetic particles (B) include crystalline particles.

8. The resin composition according to claim 1 or 2, wherein the soft magnetic particles (B) include amorphous particles.

9. The resin composition according to claim 1 or 2, wherein the soft magnetic particles (B) comprise gas-water atomized powder.

10. The resin composition according to claim 1 or 2, further comprising a phenol-based curing agent (C).

11. Further comprising a curing catalyst (D), 3. The resin composition according to claim 1, wherein the curing catalyst (D) comprises at least one selected from the group consisting of a tetra-substituted phosphonium compound, a phosphobetaine compound, an adduct of a phosphine compound and a quinone compound, and an adduct of a phosphonium compound and a silane compound.

12. The resin composition according to claim 1 or 2, further comprising a silica filler (E).

13. The resin composition according to claim 1 or 2, which has a gel time at 175°C of 30 seconds or more and 300 seconds or less.

14. 3. The resin composition according to claim 1, wherein a cured product of the resin composition has a relative magnetic permeability at 25°C of 30 or more.

15. 3. The resin composition according to claim 1, wherein a cured product of the resin composition has a saturation magnetic flux density of 0.2 T or more at 25°C.

16. The resin composition according to claim 1 or 2, wherein a cured product of the resin composition has a coefficient of linear expansion (CTE1) of 30 ppm / °C or less in the range from 25°C to the glass transition temperature of the cured product.

17. 3. The resin composition according to claim 1, wherein a cured product of the resin composition has a coefficient of linear expansion (CTE2) of 100 ppm / °C or less in the range from the glass transition temperature of the cured product to 320°C.

18. The resin composition according to claim 1 or 2, wherein a cured product of the resin composition has a flexural strength at 25°C measured in accordance with JIS K 6911:2006 of 50 MPa or more and 200 MPa or less.

19. The resin composition according to claim 1 or 2, wherein a cured product of the resin composition has a flexural modulus at 25°C measured in accordance with JIS K 6911:2006 of 20,000 MPa or more and 50,000 MPa or less.

20. The resin composition according to claim 1 or 2, wherein a cured product of the resin composition has a glass transition temperature of 100°C or higher and 250°C or lower.

21. The resin composition according to claim 1 or 2, which is solid at 25°C.

22. The resin composition according to claim 1 or 2, which is in the form of a tablet at 25°C.

23. The resin composition according to claim 1 or 2, wherein the resin composition is inserted into the hole by transfer molding.

24. A molded article obtained by curing the resin composition according to claim 1 or 2.

25. 25. The molded article according to claim 24, which is a transfer molded article.

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