Resin molding material, molded body, and method for manufacturing said molded body

Abstract

This resin molding material contains (A) soft magnetic particles, (B) a fine silica powder that has an average particle diameter of from 0.1 μm to 2.0 μm, and (C) a thermosetting resin. The content of the soft magnetic particles (A) is 96% by mass or more; and the content of the fine silica powder (B) is 1.5% by mass or less.

Description

[Technical Field]

[0001] The present invention relates to a resin molding material, a molded article, and a method for producing the molded article. [Background technology]

[0002] Coils (also called "reactors" or "inductors" depending on the application field) with magnetic cores and exterior materials are being actively studied as components for various electrical and electronic products. Furthermore, moldable magnetic materials for producing the magnetic cores and exterior materials of such coils are also being actively studied.

[0003] For example, Patent Document 1 discloses a molding material containing a magnetic powder containing first particles that exhibit soft magnetism and have an iron content of 85 mass % or more, and a non-magnetic powder that exhibits non-magnetic properties and has an average particle size of 3 μm or less and is smaller than the magnetic powder. The document states that the volume fraction of the magnetic powder is 50 to 90 volume % of molding material 1 (paragraph 0107, etc.), and that the volume fraction of the non-magnetic powder containing silica is 3 to 25 volume % of the magnetic powder (paragraph 0124, etc.).

[0004] Patent Document 2 discloses a resin composition for forming a magnetic core, which contains a thermosetting resin and a magnetic powder, the content of which is 50 mass % or more of the magnetic powder relative to the total solid content of the resin composition for forming a magnetic core. The document also states that the volume fraction of the magnetic powder is 35 to 90 volume % of molding material 1 (paragraph 0107, etc.), and that the volume fraction of the non-magnetic powder containing silica is 3 to 25 volume % of the magnetic powder (paragraph 0124, etc.). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-182950 [Patent Document 2] Japanese Patent Application Publication No. 2019-080058 Summary of the Invention [Problem to be solved by the invention]

[0006] In magnetic materials obtained from resin molding materials (compositions), a high loading of soft magnetic particles is necessary to improve magnetic properties such as magnetic permeability. However, increasing the loading amount of soft magnetic particles increases the viscosity of the resin molding material, which reduces its ability to fill into a mold during molding such as compression molding. In other words, there is a trade-off between increasing the magnetic permeability of the magnetic material and improving its ability to fill into a mold.

[0007] In Patent Documents 1 and 2, the filling amount of magnetic particles is small and the purpose is not to solve the above-mentioned problems, and there is room for improvement in increasing the magnetic permeability of the magnetic material and in the fillability into the mold. [Means for solving the problem]

[0008] As a result of extensive research, the present inventors have completed the invention provided below and solved the above-mentioned problems. That is, the present invention can be described as follows.

[0009] According to the present invention, (A) soft magnetic particles; (B) finely divided silica having an average particle size of 0.1 μm or more and 2.0 μm or less; (C) a thermosetting resin; Including, The content of the soft magnetic particles (A) is 96% by mass or more, A resin molding material is provided in which the content of finely powdered silica (B) is 1.5 mass % or less.

[0010] According to the present invention, A molded article is provided by curing the resin molding material.

[0011] According to the present invention, Injecting the melt of the resin molding material into a mold using a transfer molding device; hardening the melt; A method for producing a molded body is provided, comprising:

[0012] According to the present invention, There is provided a method for producing a molded article, which includes a step of compression molding the resin molding material. [Effects of the Invention]

[0013] According to the present invention, a magnetic material with high magnetic permeability can be obtained, and a resin molding material with excellent fillability into a mold can be provided. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 2 is a cross-sectional view showing the configuration of a structure according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all drawings, similar components are designated by similar reference numerals, and their description will be omitted where appropriate. Furthermore, unless otherwise specified, "~" indicates "above" to "below."

[0016] The resin molding material of this embodiment is The magnetic material contains (A) soft magnetic particles, (B) finely powdered silica having an average particle size of 0.1 μm or more and 2.0 μm or less, and (C) a thermosetting resin. The content of the soft magnetic particles (A) is 96% by mass or more, and the content of the finely powdered silica (B) is 1.5% by mass or less. This makes it possible to obtain a magnetic material with high magnetic permeability and to provide a resin molding material with excellent fillability into a mold. Each component will be described below.

[0017] [Soft magnetic particles (A)] Soft magnetism refers to ferromagnetism with a small coercive force, and generally, ferromagnetism with a coercive force of 800 A / m or less is called soft magnetism.

[0018] The soft magnetic particles (A) may be made of a metal-containing material having an iron content of 85% by mass or more. Metallic materials with a high iron content exhibit soft magnetic properties, such as relatively good magnetic permeability and magnetic flux density. Therefore, when molded into a magnetic core or the like, a resin molding material can be obtained that exhibits good magnetic properties.

[0019] The metal-containing material may be in the form of, for example, a simple substance, or an alloy such as a solid solution, a eutectic, or an intermetallic compound. By using particles made of such metal materials, it is possible to obtain a resin molding material having excellent magnetic properties derived from iron, i.e., magnetic properties such as high magnetic permeability and high magnetic flux density.

[0020] The metal-containing material may also contain elements other than iron as constituent elements. Examples of elements other than iron include B, C, N, O, Al, Si, P, S, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Cd, In, and Sn, and one or more of these may be used in combination. In this embodiment, one or more elements selected from Fe, Ni, Si, and Co may be included as major elements.

[0021] Specific examples of the metal-containing material include pure iron, silicon steel, iron-cobalt alloy, iron-nickel alloy, iron-chromium alloy, iron-aluminum alloy, carbonyl iron, stainless steel, and composite materials containing one or more of these. From the viewpoint of availability, silicon steel and carbonyl iron are preferably used. The soft magnetic particles (Fe-based soft magnetic particles) may be other particles, such as magnetic particles including Ni-based soft magnetic particles, Co-based soft magnetic particles, etc.

[0022] Volume-based median diameter D of soft magnetic particles (A) 50is preferably 0.5 to 75 μm, more preferably 0.75 to 65 μm, and even more preferably 1 to 60 μm. By appropriately adjusting the particle size (median diameter), it is possible to further improve the fluidity during molding and to improve the magnetic performance.

[0023] In addition, D 50 can be obtained, for example, by a laser diffraction / scattering particle size distribution measuring device. Specifically, a particle size distribution curve is obtained by measuring the soft magnetic particles (A) in a dry state using a particle size distribution measuring device "LA-950" manufactured by HORIBA Corporation, and D 50 can be obtained.

[0024] The resin molding material of this embodiment contains the soft magnetic particles (A) in an amount of 96% by mass or more, with the upper limit being 98% by mass or less, thereby making it possible to obtain a magnetic material with high magnetic permeability. The resin molding material of this embodiment contains the soft magnetic particles (A) in an amount of 82% by volume or more, preferably 84% by volume or more, with the upper limit being 90% by volume or less.

[0025] [Fine Silica (B)] The resin molding material of this embodiment contains finely divided silica (B). The finely divided silica (B) has an average particle size of 0.1 μm or more and 2.0 μm or less, preferably 0.1 μm or more and 1.8 μm or less, more preferably 0.1 μm or more and 1.6 μm or less, and even more preferably 0.1 μm or more and 1.0 μm or less. This allows the finely divided silica (B) to be uniformly dispersed in the resin molding material, improving the flowability and enhancing the filling property and moldability, thereby producing a molded product with few molding defects and further providing the molded product with particularly good magnetic properties. The finely powdered silica (B) has a high affinity with thermosetting resins and high insulating properties, and is therefore useful as a constituent material of non-magnetic powders used in resin molding materials.

[0026] The true specific gravity of the finely divided silica (B) is preferably 1.0 to 6.0, more preferably 1.2 to 5.0, and even more preferably 1.5 to 4.5. Such finely divided silica (B) has a low specific gravity and therefore easily flows together with the molten thermosetting resin. Therefore, when the molten thermosetting resin flows toward the gaps in the mold during molding, the finely divided silica (B) easily flows together with the molten resin.

[0027] The finely divided silica (B) is preferably spherical silica. The sphericity of the finely powdered silica (B) is not particularly limited, but is preferably 0.50 to 1.00, more preferably 0.75 to 1.00. When the sphericity of the finely powdered silica (B) is within the above range, the rolling property of the finely powdered silica (B) itself can be utilized to ensure the flowability of the resin molding material.

[0028] The resin molding material of this embodiment may contain the finely divided silica (B) in an amount of 1.5% by mass or less, preferably 1.2% by mass or less, and more preferably 1.0% by mass or less. From the viewpoint of the effects of the present invention, the lower limit is 0.05% by mass or more, preferably 0.1% by mass or more.

[0029] The resin molding material of this embodiment contains the soft magnetic particles (A) contained in the above-mentioned amounts as well as the finely powdered silica (B) in the above-mentioned amounts, thereby obtaining a magnetic material with high magnetic permeability and a resin molding material with sufficient fluidity and excellent fillability into a mold.

[0030] The volume fraction of the finely divided silica (B) is 4% by volume or less, preferably 3% by volume or less, and more preferably 2% by volume or less. The lower limit is 0.14% by volume or more, and preferably 0.5% by volume or more.

[0031] The average particle size of the magnetic particles (A) and the finely divided silica (B) refers to the volume average particle size (for example, D50), and can be measured using a laser diffraction particle size distribution analyzer.

[0032] The sphericity of particles such as finely divided silica (B) can be calculated by dividing the diameter of the circumscribed circle by the diameter of the equivalent circle, assuming that the circle has the same area as the particle in a scanning electron microscope (SEM) image. Then, the diameter of the equivalent circle / the diameter of the circumscribed circle is calculated for 10 or more randomly selected particles, and the average value is taken as the "sphericity of the particle."

[0033] [Thermosetting resin (C)] Examples of the thermosetting resin (C) include epoxy resins, phenolic resins, polyimide resins, bismaleimide resins, urea resins, melamine resins, polyurethane resins, cyanate ester resins, silicone resins, oxetane resins (oxetane compounds), (meth)acrylate resins, unsaturated polyester resins, diallyl phthalate resins, and benzoxazine resins. These may be used alone or in combination of two or more. From the viewpoint of heat resistance, it is preferable that the thermosetting resin (C) contains, for example, an epoxy resin. The epoxy resin is not particularly limited as long as it can exhibit the effects of the present invention, and any known compound can be used.

[0034] (epoxy resin) Examples of the epoxy resin include 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; novolac-type epoxy resins such as phenol novolac-type epoxy resin and cresol novolac-type epoxy resin; biphenyl-type epoxy resin, biphenyl aralkyl-type epoxy resin, aryl alkylene-type epoxy resin, naphthalene-type epoxy resin, anthracene-type epoxy resin, phenoxy-type epoxy resin, dicyclopentadiene-type epoxy resin, norbornene-type epoxy resin, adamantane-type epoxy resin, fluorene-type epoxy resin, and trisphenylmethane-type epoxy resin. The resin molding material of the present embodiment may contain only one type of epoxy resin or may contain two or more types of epoxy resins. Furthermore, epoxy resins of the same type but with different molecular weights may be used in combination.

[0035] From the viewpoint of the effects of the present invention, the epoxy resin of the present embodiment is preferably at least one selected from the group consisting of an epoxy resin containing a triphenylmethane structure, an epoxy resin containing a biphenyl structure, and a bisphenol A or F type epoxy resin,

[0036] In this embodiment, it is more preferable to use a combination of an epoxy resin containing a triphenylmethane structure and a bisphenol A or F type epoxy resin, or an epoxy resin containing a biphenyl structure.

[0037] Specifically, an epoxy resin containing a triphenylmethane structure is an epoxy resin containing a partial structure in which three of the four hydrogen atoms of methane (CH4) are substituted with a benzene ring. The benzene ring may be unsubstituted or substituted with a substituent. Examples of the substituent include a hydroxy group and a glycidyloxy group.

[0038] Specifically, an epoxy resin containing a triphenylmethane structure contains a structural unit represented by the following general formula (a1): Two or more of these structural units are connected together to form a triphenylmethane skeleton.

[0039] [ka]

[0040] In general formula (a1), R 11 When there are a plurality of groups, each group independently represents a monovalent organic group, a halogen atom, a hydroxy group, or a cyano group, R 12 When there are a plurality of groups, each group independently represents a monovalent organic group, a halogen atom, a hydroxy group, or a cyano group, i is an integer from 0 to 3, j is an integer of 0 to 4.

[0041] R 11 and R 12 Examples of the monovalent organic group include R in the general formula (BP) described below. a and R b Examples of the monovalent organic group include those listed as the monovalent organic group. i and j each independently represent preferably 0 to 2, and more preferably 0 to 1.

[0042] In one embodiment, both i and j are 0. That is, in one embodiment, none of the benzene rings in general formula (a1) has a monovalent substituent other than the explicitly stated glycidyloxy group.

[0043] Specifically, the biphenyl-containing epoxy resin is an epoxy resin containing a structure in which two benzene rings are connected by a single bond. The benzene rings may or may not have a substituent. Specifically, an epoxy resin containing a biphenyl structure has a partial structure represented by the following general formula (BP).

[0044] [ka]

[0045] In general formula (BP), R a and R b When there are a plurality of groups, each group independently represents a monovalent organic group, a hydroxyl group, or a halogen atom; r and s each independently represent 0 to 4; * indicates a bond to another atomic group.

[0046] R a and R bSpecific examples of the monovalent organic group include an alkyl group, an alkenyl group, an alkynyl group, an alkylidene group, an aryl group, an aralkyl group, an alkaryl group, a cycloalkyl group, an alkoxy group, a heterocyclic group, and a carboxyl group.

[0047] Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group. Examples of the alkenyl group include an allyl group, a pentenyl group, and a vinyl group. The alkynyl group includes, for example, an ethynyl group. Examples of the alkylidene group include a methylidene group and an ethylidene group. Examples of the aryl group include a tolyl group, a xylyl group, a phenyl group, a naphthyl group, and an anthracenyl group. Examples of the aralkyl group include a benzyl group and a phenethyl group. Examples of the alkaryl group include a tolyl group and a xylyl group. Examples of the cycloalkyl group include an adamantyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group.

[0048] Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an s-butoxy group, an isobutoxy group, a t-butoxy group, an n-pentyloxy group, a neopentyloxy group, and an n-hexyloxy group. Examples of the heterocyclic group include an epoxy group and an oxetanyl group. R a and R b The total number of carbon atoms in each of the monovalent organic groups is, for example, 1 to 30, preferably 1 to 20, more preferably 1 to 10, and particularly preferably 1 to 6. Each of r and s is independently preferably 0 to 2, more preferably 0 to 1. In one embodiment, both r and s are 0.

[0049] More specifically, the epoxy resin containing a biphenyl structure is preferably a biphenylaralkyl epoxy resin having a structural unit represented by the following general formula (BP1).

[0050] [ka]

[0051] In general formula (BP1), R a and R b The definition and specific embodiments of are the same as those of general formula (BP), The definitions and preferred ranges of r and s are the same as those in general formula (BP), R c When there are a plurality of groups, each group independently represents a monovalent organic group, a hydroxyl group, or a halogen atom; t is an integer of 0 to 3. R c Specific examples of the monovalent organic group include R a and R b Examples of the above include those given as specific examples. t is preferably 0 to 2, and more preferably 0 to 1.

[0052] Specific examples of bisphenol A or F type epoxy resins (epoxy resins produced by a condensation reaction between bisphenol A or bisphenol F and epichlorohydrin) include epoxy resins represented by the following general formula (EP):

[0053] [ka]

[0054] In the general formula (EP), each of the plurality of R's independently represents a hydrogen atom or a methyl group, preferably a methyl group; R a , R b , R c and R d each, when a plurality of groups are present, is independently a monovalent organic group, a hydroxyl group, or a halogen atom; p, q, r, and s each independently represent an integer of 0 to 4, preferably 0 to 2; n is an integer of 0 or more, usually 0 to 10, and preferably 0 to 5.

[0055] R a , R b , R c and R d Specific examples of the monovalent organic group include R in general formula (BP): a and R b Specific examples of the monovalent organic group include the same as those given above. In this embodiment, it is preferable to use a bisphenol A type epoxy resin in which R is a methyl group.

[0056] The amount of epoxy resin in the resin molding material of this embodiment is, for example, 0.1 to 20 mass %, and preferably 0.5 to 10 mass %. The amount of epoxy resin in the resin molding material of this embodiment is, for example, 0.5 to 60% by volume, and preferably 3 to 40% by volume.

[0057] (phenolic resin) The phenolic resin is not particularly limited, but examples thereof include novolac-type phenolic resins such as phenol novolac resin, cresol novolac resin, and bisphenol A novolac resin, and resol-type phenolic resins, etc. One of these may be used alone, or two or more may be used in combination. Among the phenolic resins, phenolic novolac resins are preferred.

[0058] (urea resin) The urea resin is not particularly limited, but examples thereof include resins obtained by condensation of urea and formaldehyde.

[0059] (melamine resin) The melamine resin is not particularly limited, but for example, a resin obtained by reacting melamine with formaldehyde under neutral or weak alkaline conditions can be used. As the melamine resin, commercially available melamine resins such as those manufactured by Sumitomo Chemical Co., Ltd. may also be used.

[0060] (unsaturated polyester resin) The unsaturated polyester resin is not particularly limited, but includes, for example, the most common ortho-type, which uses phthalic anhydride as a raw material, the iso-type, which uses isophthalic acid, and the para-type, which uses terephthalic acid, as well as prepolymers thereof. These can be used alone or in combination of two or more.

[0061] (Polyimide resin) The polyimide resin is not particularly limited, but may be synthesized, for example, by copolymerizing a diamine, a dianhydride, and an anhydride to synthesize a polyamic acid, which is a precursor of polyimide, and then imidizing the polyamic acid.

[0062] [Phenol-based hardener (D)] The resin molding material of this embodiment may further contain a phenol-based curing agent (D). This is expected to further improve the durability of the resulting molded article, etc. Phenol-based curing agents typically have two or more hydroxy groups per molecule.

[0063] The phenolic curing agent preferably contains a skeleton selected from the group consisting of a novolak skeleton and a biphenyl skeleton. When the phenolic curing agent contains any of these skeletons, the durability of the molded article can be particularly improved. Specifically, the "biphenyl skeleton" is a structure in which two benzene rings are linked by a single bond, as in the general formula (BP) in the explanation of the epoxy resin mentioned above.

[0064] Specific examples of phenolic curing agents having a biphenyl skeleton include those having a structure in which the glycidyl group in the general formula (BP1) in the explanation of the epoxy resins above is replaced with a hydrogen atom. Specific examples of phenolic curing agents having a novolac skeleton include those having a structural unit represented by the following general formula (N).

[0065] [ka]

[0066] In general formula (N), R 4 represents a monovalent substituent, u is an integer of 0 to 3. R 4 Specific examples of the monovalent substituent include R in general formula (BP): a and R b Examples of the monovalent substituent include those described above. u is preferably 0 to 2, more preferably 0 to 1, and even more preferably 0.

[0067] In this embodiment, the phenolic curing agent (D) is preferably at least one selected from novolac-type phenolic resins and biphenylaralkyl-type phenolic resins.

[0068] When the phenolic curing agent (D) is a polymer or oligomer, the number average molecular weight of the phenolic curing agent (D) (measured by GPC and converted into standard polystyrene) is about 200 to 800, for example.

[0069] The content of the phenolic curing agent (D) in the resin molding material is, for example, 0.1 to 20 mass %, and preferably 0.5 to 10 mass %. The content of the phenolic curing agent (D) in the resin molding material is, for example, 0.5 to 60% by volume, and preferably 3 to 40% by volume. By appropriately adjusting the amount of the phenolic curing agent (D), it is possible to further improve the flowability, and to improve the mechanical and magnetic properties of the resulting cured product.

[0070] [Curing accelerator (E)] The resin molding material of the present embodiment may further contain a curing accelerator (E). The curing accelerator (E) is not particularly limited as long as it accelerates the curing reaction of the epoxy resin, and known epoxy curing accelerators can be used.

[0071] Specific examples include phosphorus atom-containing compounds such as organic phosphines, tetra-substituted phosphonium compounds, phosphobetaine compounds, adducts of phosphine compounds and quinone compounds, and adducts of phosphonium compounds and silane compounds; imidazoles (imidazole curing accelerators) such as 2-methylimidazole and 2-phenylimidazole; and nitrogen atom-containing compounds such as amidines and tertiary amines, exemplified by 1,8-diazabicyclo[5.4.0]undecene-7 and benzyldimethylamine, as well as quaternary salts of amidines and amines.

[0072] Preferred are tetra-substituted phosphonium compounds, phosphobetaine compounds, phosphine compounds, adducts of phosphine compounds and quinone compounds, and adducts of phosphonium compounds and silane compounds. When the curing accelerator (E) is used, only one kind may be used, or two or more kinds may be used.

[0073] When the curing accelerator (E) is used, its content is preferably 0.01 to 1 mass %, more preferably 0.04 to 0.8 mass %, based on the total resin molding material. The volume fraction is preferably 0.05 to 5 volume %, more preferably 0.10 to 0.4 volume %. By setting the content within this range, a sufficient curing acceleration effect can be obtained without excessively impairing other performances.

[0074] [Silicone compounds (F)] The resin molding material of this embodiment may further contain a silicone compound (F).

[0075] By including the silicone compound (F), the fluidity of the resin molding material is further increased, resulting in superior filling properties into the mold, and the wettability is also improved, thereby suppressing the occurrence of voids and the like.

[0076] As the silicone compound (F), any known silicone compound can be used as long as it achieves the effects of the present invention, but preferably a silicone compound represented by the following general formula (1) can be used.

[0077] [ka]

[0078] In general formula (1), R each independently represents a substituted or unsubstituted monovalent organic group having 1 to 10 carbon atoms, and at least one of R is a group selected from an amino-substituted organic group, an epoxy-substituted organic group, a polyoxyalkylene-containing organic group, a hydroxyl-substituted organic group, a vinyl-substituted organic group, a carboxyl-substituted organic group, an isocyanate-substituted organic group, a mercapto-substituted organic group, a (meth)acrylic-substituted organic group, and an acid anhydride-substituted organic group. n represents an integer of 1 to 100. When at least one of R is the above group, the remaining R is preferably an alkyl group or alkoxy group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms, and even more preferably an alkyl group having 1 to 5 carbon atoms. In this embodiment, from the viewpoint of the effects of the present invention, it is preferable that at least one of R is an epoxy-substituted organic group. The silicone compound (F) is preferably liquid at room temperature (25°C). From the viewpoint of the effects of the present invention, the functional group equivalent weight of the silicone compound (F) is preferably 200 to 30,000, more preferably 300 to 20,000. The weight average molecular weight of the silicone compound (F) is preferably 200 to 10,000, more preferably 500 to 8,000.

[0079] As the silicone compound (F), it is preferable to use a silicone compound represented by the following general formula (1a).

[0080] [ka]

[0081] In general formula (1a), Q is an epoxy-substituted organic group or a polyoxyalkylene-containing organic group, and multiple Qs may be the same or different. It is preferred that Q contains an epoxy-substituted organic group. a represents an integer of 1 to 50, and b represents an integer of 1 to 50.

[0082] The epoxy-substituted organic group can be represented by the following general formula (a).

[0083] [ka]

[0084] In formula (a), X 1 represents an alkylene group having 1 to 10 carbon atoms or an oxyalkylene group having 1 to 10 carbon atoms, and the alkylene group may contain an ether group. * represents a bond.

[0085] The polyoxyalkylene group-containing organic group can be represented by the following general formula (b).

[0086] [ka]

[0087] In formula (b), X 2 represents an alkylene group having 1 to 10 carbon atoms or an oxyalkylene group having 1 to 10 carbon atoms, and R 1 represents a hydrogen atom or an alkylene group having 1 to 3 carbon atoms. c represents an integer of 1 to 20, and d represents an integer of 1 to 20. * indicates a bond.

[0088] Examples of the silicone compound (F) include SF8421EG, FZ-3730, BY16-869, BY16-870, X-22-4741, X-22-178SX, X-22-178DX (all manufactured by Dow Corning Toray Co., Ltd.), KF-1002, and X-22-343 (all manufactured by Shin-Etsu Chemical Co., Ltd.).

[0089] The resin molding material of this embodiment can contain the silicone compound (F) in an amount of 0.5% by mass or less, preferably 0.4% by mass or less, and more preferably 0.3% by mass or less. The lower limit is 0.01% by mass or more, preferably 0.05% by mass or more. This further increases the fluidity of the resin molding material, resulting in particularly excellent mold filling properties, improved wettability, and further suppression of voids and the like. Note that in this embodiment, the silicone compound (F) is not added for the purpose of improving molding shrinkage, and the amount added is preferably within the above range.

[0090] [Carboxylic acid dispersant] The resin molding material of this embodiment may further contain a carboxylic acid-based dispersant. By containing a carboxylic acid-based dispersant, the fillability of the resin molding material into a mold can be further improved.

[0091] The carboxylic acid dispersant is not particularly limited and any conventionally known compound can be used as long as it can exhibit the effects of the present invention. In this embodiment, the carboxylic acid dispersant preferably contains at least one compound represented by the following general formula (i):

[0092] [ka]

[0093] In general formula (i), R represents a carboxyl group, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylcarboxyl group having 1 to 5 carbon atoms, an alkoxycarboxyl group having 1 to 5 carbon atoms, an alkylalcohol group having 1 to 5 carbon atoms, or an alkoxyalcohol group having 1 to 5 carbon atoms, and multiple Rs may be the same or different.

[0094] R is preferably a carboxyl group, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an alkylcarboxyl group having 1 to 5 carbon atoms.

[0095] X represents an oxygen atom, an alkylene group having 1 to 30 carbon atoms, a divalent chain hydrocarbon group having 1 to 30 carbon atoms and one or more double bonds, or a divalent chain hydrocarbon group having 1 to 30 carbon atoms and one or more triple bonds, and multiple Xs may be the same or different. Examples of the divalent chain hydrocarbon group include alkylene groups.

[0096] X is preferably an oxygen atom, an alkylene group having 1 to 20 carbon atoms, or a divalent chain hydrocarbon group having 1 to 20 carbon atoms and one or more double bonds, and more preferably an oxygen atom, an alkylene group having 1 to 20 carbon atoms, or an alkylene group having 1 to 20 carbon atoms and one double bond. n is an integer of 0 to 20, and m is an integer of 1 to 5.

[0097] The compound represented by general formula (i) is preferably a compound represented by the following general formula (ia) or general formula (ib): The carboxylic acid-based dispersant may contain at least one selected from these.

[0098] [ka]

[0099] In the general formula (ia), R, m, and n have the same meanings as in the general formula (i).

[0100] [ka]

[0101] In formula (ib), Q represents an alkylene group having 1 to 5 carbon atoms, and is preferably an alkylene group having 1 to 3 carbon atoms. X has the same meaning as in formula (i).

[0102] The acid value of the carboxylic acid dispersant is 5 to 500 mgKOH / g, preferably 10 to 350 mgKOH / g, and more preferably 15 to 100 mgKOH / g. When the acid value is within the above range, a magnetic material having a high saturation magnetic flux density is obtained, and the magnetic material has excellent flowability and moldability. The carboxylic acid dispersant is preferably in the form of a solid or a wax.

[0103] From the viewpoint of the effects of the present invention, the content of the carboxylic acid dispersant is 0.01% by mass or more and 2% by mass or less, and preferably 0.05% by mass or more and 1% by mass or less, relative to 100% by mass of the resin molding material.

[0104] Examples of the compound represented by general formula (i) contained in the carboxylic acid-based dispersant include Hypermer KD-4 (mass average molecular weight: 1700, acid value: 33 mg KOH / g), Hypermer KD-9 (mass average molecular weight: 760, acid value: 74 mg KOH / g), Hypermer KD-12 (mass average molecular weight: 490, acid value: 111 mg KOH / g), and Hypermer KD-16 (mass average molecular weight: 370, acid value: 299 mg KOH / g), all manufactured by CRODA.

[0105] (Other ingredients) The resin molding material of this embodiment may contain components other than those described above, such as one or more of a stress reducing agent, a coupling agent, an adhesion aid, a mold release agent, a colorant, an antioxidant, a corrosion resistant agent, a dye, a pigment, and a flame retardant.

[0106] Examples of the low stress agent include a polybutadiene compound, an acrylonitrile butadiene copolymer compound, a silicone compound such as silicone oil or silicone rubber, etc. When a low stress agent is used, only one type may be used, or two or more types may be used in combination.

[0107] The coupling agent may be any of the coupling agents used in the surface treatment of magnetic particles. Examples include silane-based coupling agents, titanium-based coupling agents, zirconia-based coupling agents, and aluminum-based coupling agents. When using a coupling agent, only one type may be used, or two or more types may be used in combination.

[0108] The resin molding material of this embodiment can be produced industrially, for example, by first (1) mixing the components using a mixer, (2) then kneading using a roll at around 120°C for 5 minutes or more, preferably 10 minutes, to obtain a kneaded mixture, (3) cooling the obtained kneaded mixture, and (4) subsequently pulverizing it. This process allows for the production of a powdered resin molding material. The powdered resin molding material of this embodiment has excellent fluidity and improved handleability because it is inhibited from agglomerating and solidifying.

[0109] (Form of resin molding material) The resin molding material of this embodiment is preferably in tablet or granular form, more preferably in tablet form, at 23° C. The powdered resin molding material can be compressed into tablets. When the resin molding material is in tablet or granular form, distribution and storage of the resin molding material are facilitated, and the resin molding material is also easily applicable to transfer molding and compression molding. The powdered resin molding material of this embodiment is inhibited from agglomerating and solidifying, and can be made into a tablet or granular composition of uniform composition.

[0110] (Characteristics when resin molding material is melted) The resin molding material of this embodiment contains a predetermined amount of finely divided silica (B), which can improve the fluidity of the resin molding material when melted, thereby enhancing the filling property, moldability, etc.

[0111] The fillability of a resin molding material can be accurately confirmed by the "spreadability test" described below, which allows for accurate confirmation of the fillability and moldability of the resin molding material when melted. In other words, the spreadability test allows for confirmation of the melting and spreading properties of the molten material when stress is continuously applied to the entire molten resin molding material, allowing for more accurate confirmation of its moldability and fillability into molds under conditions similar to those of actual manufacturing processes. The excellent properties of a resin molding material allow for accurate confirmation of its moldability and fillability into the fine details of the mold in injection molding. In particular, compression molding allows for accurate confirmation of moldability and fillability when the material is placed in a mold and heated and pressed. (Spreadability test) A spoonful (2.0 ml) of resin molding material for gel measurement is placed on a gel plate at 175°C. A thin burr measurement mold (lower mold 3,000 g) heated to 175°C is placed on top of it and left for 5 minutes. The thin burr measurement mold is removed, and the diameter of the resin molding material that has been pressed out into an approximately circular shape is measured.

[0112] Specifically, the flow length measured by a spiral flow test at a temperature of 175°C can be 30 cm or more, preferably 40 cm or more, and more preferably 45 cm or more.

[0113] The spiral flow test can be performed, for example, using a low-pressure transfer molding machine (KTS-15 manufactured by Kotaki Seiki Co., Ltd.) by injecting a resin molding material into a spiral flow measurement mold conforming to EMMI-1-66 under conditions of a mold temperature of 175°C, an injection pressure of 6.9 MPa, and a pressure holding time of 180 seconds, and measuring the flow length.

[0114] Furthermore, the resin molding material of this embodiment can have a high viscosity of 30 Pa·s or more and 300 Pa·s or less, preferably 50 Pa·s or more and 250 Pa·s or less, and more preferably 60 Pa·s or more and 200 Pa·s or less, measured using a high viscosity measuring device at a measurement temperature of 175°C and a load of 40 kgf.

[0115] (glass transition temperature of cured product) The resin molding material of this embodiment is melted at 175°C, molded, and then post-cured at 175°C in the atmosphere for 4 hours. The cured product has a glass transition temperature of preferably 150 to 220°C, more preferably 160 to 200°C. Designing a resin molding material so that the glass transition temperature is 150°C or higher makes it easier to meet the heat resistance requirements, for example, for in-vehicle applications. Designing a resin molding material so that the glass transition temperature is 220°C or lower enables molding at relatively low temperatures. This is advantageous in terms of suppressing shrinkage of molded products due to low-temperature processing.

[0116] <Molded body> The molded body of this embodiment can be obtained by curing the above-mentioned resin molding material. The powdered resin molding material of this embodiment is highly filled with soft magnetic particles (A), but has excellent packing properties and moldability, so the resulting molded body (magnetic material) has a uniform composition and can exhibit desired properties in terms of magnetic properties such as magnetic permeability and saturation magnetic flux density, as well as mechanical strength. Specifically, the molded body of this embodiment has a relative magnetic permeability of 40 or more, preferably 42 or more, and more preferably 45 or more.

[0117] Furthermore, since the molded body of this embodiment has a uniform composition as described above and is made of a composite material with a high saturation magnetic flux density, it can achieve a high saturation magnetic flux density of 1.0 T or more, preferably 1.2 T or more, and more preferably 1.3 T or more.

[0118] The method for producing the molded body is not particularly limited, but examples thereof include transfer molding and compression molding.

[0119] (Transfer molding method) A method for producing a molded body using transfer molding includes the steps of injecting a melt of the above-mentioned resin molding material into a mold using a transfer molding device, hardening the melt, and releasing the molded body from the mold.

[0120] Transfer molding can be performed using a known transfer molding device. Specifically, first, a preheated resin molding material is placed in a heating chamber, also known as a transfer chamber, and melted to obtain a molten material. The molten material is then injected into a mold using a plunger and held there until the molten material hardens. This allows the desired molded product to be obtained. Transfer molding is preferable in terms of the controllability of the dimensions of the molded body and the improvement of the degree of freedom in shape.

[0121] Various conditions for transfer molding can be set as desired. For example, the preheating temperature can be set to 60 to 100°C, the heating temperature during melting to 100 to 250°C, the mold temperature to 100 to 200°C, and the pressure during injection of the molten resin molding material into the mold can be adjusted as appropriate to within a range of 1 to 20 MPa. Shrinkage of the molded product can be suppressed by not raising the mold temperature too high.

[0122] (Compression molding method) The method for producing a molded body by compression molding includes a step of compression molding the resin molding material. Specifically, the method includes a step of compression molding the resin molding material of the present embodiment in a mold and a step of releasing the molded body from the mold.

[0123] Compression molding can be performed using a known compression molding device. Specifically, the resin molding material is placed in a recess of a fixed mold having a concave shape and an opening at the top. The resin molding material can be preheated. This allows the molded body to be cured uniformly and the molding pressure to be reduced.

[0124] Next, the convex mold is moved from above onto the fixed concave mold, and the resin molding material is compressed within the cavity formed by the convex and concave portions. Initially, low pressure is applied to sufficiently soften and flow the resin molding material, and then the mold is closed and pressure is applied again to harden it for a predetermined period of time.

[0125] The various conditions for compression molding can be set as desired, for example, the preheating temperature can be set to 60 to 100°C, the heating temperature during melting can be set to 100 to 250°C, the mold temperature can be set to 100 to 200°C, the pressure during compression of the resin molding material in the mold can be set to 1 to 20 MPa, and the curing time can be set to 60 to 300 seconds. Shrinkage of the molded product can be suppressed by not raising the mold temperature too high.

[0126] Since the resin molding material of this embodiment can produce a magnetic material with high magnetic permeability, the molded body obtained by hardening the resin molding material can be used for the magnetic core in an inductor or for an exterior component that seals the magnetic core and coil.

[0127] An outline of a structure (integrated inductor) having an exterior member made of a cured resin molding material of this embodiment will be described with reference to FIG. Fig. 1(a) shows an outline of the structure as seen from above the structure 100. Fig. 1(b) shows a cross-sectional view taken along the line AA' in Fig. 1(a).

[0128] As shown in FIG. 1, the structure 100 of this embodiment can include a coil 10 and a magnetic core 20. The magnetic core 20 is filled inside the coil 10, which is an air-core coil. The coil 10 and the magnetic core 20 are sealed with an exterior member 30 (sealing member). The magnetic core 20 and the exterior member 30 can be made of a cured product of the resin molding material of this embodiment. The magnetic core 20 and the exterior member 30 can also be formed as a seamless, integrated member.

[0129] In a method for manufacturing the structure 100 of this embodiment, for example, the coil 10 is placed in a mold, and the resin molding material of this embodiment is used to perform mold molding such as transfer molding, thereby hardening the resin molding material, thereby integrally forming the magnetic core 20 filled in the coil 10 and the exterior member 30 around them. In this case, the coil 10 may have an extraction portion (not shown) where the end of the winding is extracted to the outside of the exterior member 30.

[0130] The coil 10 is typically constructed by winding a metal wire with an insulating coating on its surface. The metal wire is preferably highly conductive, and copper or copper alloys are suitable. The insulating coating may be enamel or other suitable materials. The cross-sectional shape of the winding may be circular, rectangular, hexagonal, or the like.

[0131] On the other hand, the cross-sectional shape of the magnetic core 20 is not particularly limited, but may be, for example, a circular shape or a polygonal shape such as a square or hexagon in cross section. The magnetic core 20 is made of a transfer molded product of the resin molding material of this embodiment, and therefore can have any desired shape.

[0132] The cured resin molding material of this embodiment can provide a magnetic core 20 and an exterior member 30 with excellent magnetic properties, such as moldability and high magnetic permeability, and therefore a structure 100 (integrated inductor) having these components is expected to have low magnetic loss. Furthermore, the exterior member 30 can have excellent mechanical properties, which can improve the durability, reliability, and manufacturing stability of the structure 100. Therefore, the structure 100 of this embodiment can be used in a boost circuit or a large current inductor.

[0133] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can be adopted as long as they do not impair the effects of the present invention. [Example]

[0134] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0135] <Examples 1 to 7 and Comparative Examples 1 to 5> First, the components shown in Table 1 were prepared in the ratios shown, and while mixing the soft magnetic particles, the other components were added and mixed uniformly to obtain a mixture. The resulting mixture was then kneaded at 120°C for 10 minutes. After kneading was completed, the resulting kneaded product was cooled to room temperature to solidify, and then pulverized and tableted. As a result, a tablet-shaped resin molding material was obtained. The raw material components listed in Table 1 are shown below. The evaluation results of the resin molding materials and molded products in Table 1 are shown below. The content (volume %) of soft magnetic particles listed in Table 1 is the content (i.e., filling rate) when the resin molding material containing the soft magnetic particles is taken as 100 volume %.

[0136] (Soft magnetic particles) Iron-based particles 1: amorphous magnetic powder (Epson Atmix Corporation, KUAMET6B2, median diameter D 50 :50μm) Iron-based particles 2: amorphous magnetic powder (Epson Atmix Corporation, AW2-08, median diameter D50 :4μm)

[0137] (silica) Fine powder silica 1: Fused silica, median type D 50 =0.5μm Ultra-fine silica 1: AEROSIL-RX200, median type D 50 =12nm Silica 1: SC-5500-SQ, median type D 50 =1.6μm, manufactured by Adma Silica 2: TS-6021, median type D 50 =10μm, manufactured by Micron Corporation

[0138] (epoxy resin) Epoxy resin 1: jER1032H60: an epoxy resin containing a triphenylmethane structure, manufactured by Mitsubishi Chemical Corporation, solid at 23°C, containing the structural unit represented by the general formula (a1) shown above Epoxy resin 2: YL-6810: bisphenol A type epoxy resin manufactured by Mitsubishi Chemical Corporation, solid at 23°C, containing the structure represented by the general formula (EP) shown above Epoxy resin 3: NC3000L: a biphenyl aralkyl type epoxy resin manufactured by Nippon Kayaku Co., Ltd., solid at 23°C, containing the structural unit represented by the general formula (BP1) shown above

[0139] (hardening agent) Hardener 1: PR-HF-3: Novolac type phenolic resin manufactured by Sumitomo Bakelite Co., Ltd., solid at 23°C Curing agent 2: MEH-7851SS: biphenylene skeleton-containing phenol aralkyl resin manufactured by Meiwa Kasei Co., Ltd., solid at 23°C

[0140] (adhesion aid) Adhesion aid 1: CDA-1M (heavy metal deactivator, manufactured by ADEKA)

[0141] (mold release agent) Release agent 1: WE-4 (wax, manufactured by Clariant Chemicals)

[0142] (catalyst) Catalyst 1: A compound represented by the following chemical formula [ka] A separable flask equipped with a stirrer was charged with 37.5 g (0.15 mol) of 4,4'-bisphenol S and 100 ml of methanol, and the mixture was stirred and dissolved at room temperature. A solution of 4.0 g (0.1 mol) of sodium hydroxide dissolved in 50 ml of methanol was then added with further stirring. A solution of 41.9 g (0.1 mol) of tetraphenylphosphonium bromide dissolved in 150 ml of methanol was then added. Stirring was continued for a while, and 300 ml of methanol was then added. The solution in the flask was then added dropwise to a large amount of water with stirring, yielding a white precipitate. The precipitate was filtered and dried to obtain the above-mentioned Catalyst 1 as white crystals.

[0143] Catalyst 2: A compound represented by the following chemical formula [ka] 249.5g of phenyltrimethoxysilane and 384.0g of 2,3-dihydroxynaphthalene were dissolved in a flask containing 1800g of methanol, and then 231.5g of 28% sodium methoxide-methanol solution was added dropwise at room temperature with stirring. A previously prepared solution of 503.0g of tetraphenylphosphonium bromide dissolved in 600g of methanol was then added dropwise at room temperature with stirring, resulting in the precipitation of crystals. The precipitated crystals were filtered, washed with water, and vacuum dried to obtain Catalyst 2 as pink-white crystals.

[0144] (coupling agent) Coupling agent 1: CF-4083 (phenylaminopropyltrimethoxysilane, manufactured by Dow Corning Toray Co., Ltd.)

[0145] (metal dispersant) Dispersant 1: Hypermer KD-9 (mass average molecular weight: 760, acid value: 74 mg KOH / g, manufactured by CRODA)

[0146] (silicone compounds) Silicone oil: Silicone oil represented by the following chemical formula (liquid at room temperature (25°C), FZ-3730, manufactured by Dow Corning Toray Co., Ltd.)

[0147] [ka]

[0148] <Evaluation> (Spreadability test) A spoonful (2.0 ml) of resin molding material for gel measurement was placed on a gel plate at 175°C. A thin burr measurement mold (lower mold 3,000 g) heated to 175°C was placed on top of it and left for 5 minutes. The thin burr measurement mold was removed, and the diameter of the resin molding material pressed out into a roughly circular shape was measured.

[0149] (Fluidity: Spiral flow test) A spiral flow test was carried out using the resin molding materials of the examples and comparative examples. The test was performed using a low-pressure transfer molding machine (Kotaki Seiki Co., Ltd., "KTS-15"), injecting the resin molding material into a spiral flow measurement mold conforming to EMMI-1-66 under conditions of a mold temperature of 175°C, an injection pressure of 6.9 MPa, and a dwell time of 180 seconds, and measuring the flow length. A larger value indicates better fluidity.

[0150] (high-grade viscosity) The viscosity of the resin molding material was measured using a high-temperature viscosity measuring device (High-temperature Flow Tester, Shimadzu Corporation, CFT-100EX) under the conditions of a measurement temperature of 175°C, a load of 40 kgf, and nozzle dimensions: diameter 1.0 mm x length 10 mm.

[0151] (relative permeability) The resin molding material was injected into a low-pressure transfer molding machine (Kotaki Seiki Co., Ltd., "KTS-30") at a mold temperature of 175°C, injection pressure of 9.8 MPa, and curing time of 120 seconds to obtain a disk-shaped molded product with a diameter of 50 mm and a thickness of 3 mm. The molded product was then post-cured at 175°C for 4 hours. It was then machined 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 for evaluating relative magnetic permeability. A 42-turn primary coil and a 42-turn secondary coil were wound around the resulting toroidal molded product, and AC measurements were performed using a DC / AC magnetization characteristic tester (Metron Giken Co., Ltd., "MTR-1488"). The relative magnetic permeability was measured at a frequency of 50 kHz and a magnetic flux density of 50 mT.

[0152] [Table 1]

[0153] As shown in Table 1, in comparisons between Comparative Example 1 and Examples 1 and 2, Comparative Example 2 and Examples 3 to 5, Comparative Examples 3 and 4 and Example 6, and Comparative Example 5 and Example 7, the resin molding materials of the Examples according to the present invention had a large diameter and excellent melting and spreading properties when stress was continuously applied to the entire molten resin molding material as a result of the spreading test, which suggested that they would be excellent in terms of fillability into a mold, moldability, etc. Furthermore, because it was possible to achieve a high filling rate of soft magnetic particles, a magnetic material with high magnetic permeability was obtained.

[0154] This application claims priority based on Japanese Patent Application No. 2020-168306, filed on October 5, 2020, the disclosure of which is incorporated herein in its entirety. [Explanation of symbols]

[0155] 100 structures 10 coils 20 Magnetic Core 30 Exterior materials

Claims

1. (A) soft magnetic particles; (B) finely divided silica having an average particle size of 0.1 μm or more and 2.0 μm or less; (C) a thermosetting resin; Including, The content of the soft magnetic particles (A) is 96% by mass or more, A resin molding material having a content of finely powdered silica (B) of 1.5 mass% or less.

2. The resin molding material according to claim 1 , wherein the thermosetting resin (C) comprises an epoxy resin.

3. 3. The resin molding material according to claim 2, wherein the epoxy resin is at least one selected from the group consisting of bisphenol A type epoxy resins, trisphenylmethane type epoxy resins, and biphenylaralkyl type epoxy resins.

4. The resin molding material according to any one of claims 1 to 3, further comprising a phenol-based curing agent (D).

5. 5. The resin molding material according to claim 4, wherein the phenolic curing agent (D) is at least one selected from the group consisting of novolac-type phenolic resins and biphenylaralkyl-type phenolic resins.

6. Further containing a curing accelerator (E), The resin molding material according to any one of claims 1 to 5, wherein the curing accelerator (E) is at least one selected from the group consisting of a tetra-substituted phosphonium compound, a phosphobetaine compound, a phosphine compound, an adduct of a phosphine compound and a quinone compound, and an adduct of a phosphonium compound and a silane compound.

7. The resin molding material according to any one of claims 1 to 6, further comprising a silicone compound (F).

8. The resin molding material according to claim 7, wherein the silicone compound (F) is represented by the following general formula (1): 【Chemistry 1】 (In general formula (1), each R independently represents a substituted or unsubstituted monovalent organic group having 1 to 10 carbon atoms, and at least one of R is a group selected from an amino group-substituted organic group, an epoxy group-substituted organic group, a polyoxyalkylene group-containing organic group, a hydroxyl group-substituted organic group, a vinyl group-substituted organic group, a carboxyl group-substituted organic group, an isocyanate group-substituted organic group, a mercapto group-substituted organic group, a (meth)acrylic group-substituted organic group, and an acid anhydride group-substituted organic group; and n represents an integer of 1 to 100.)

9. The resin molding material according to any one of claims 1 to 8, which is in tablet or granular form at 23°C.

10. The resin molding material according to any one of claims 1 to 9, wherein the spiral flow length measured according to EMMI-1-66 under conditions of a mold temperature of 175 ° C, an injection pressure of 6.9 MPa, and a pressure retention time of 180 seconds is 30 cm or more.

11. The resin molding material according to any one of claims 1 to 10, wherein the viscosity measured using a high-temperature viscosity measuring device under conditions of a measurement temperature of 175 ° C. and a load of 40 kgf is 30 Pa s or more and 300 Pa s or less.

12. A molded article obtained by curing the resin molding material according to any one of claims 1 to 11.

13. The molded article according to claim 12, having a relative magnetic permeability of 40 or more.

14. A step of injecting a melt of the resin molding material according to any one of claims 1 to 11 into a mold using a transfer molding device; hardening the melt; A method for producing a molded body, comprising:

15. A method for producing a molded article, comprising a step of compression molding the resin molding material according to any one of claims 1 to 11.

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