Magnetic powder composition and electronic component

Abstract

This magnetic powder composition contains a magnetic powder. The magnetic powder contains a nanocrystalline magnetic powder (A1) having an average particle diameter that is greater than 2 μm but is less than 5.5 μm. The nanocrystalline powder content of the magnetic powder composition is no less than 60.5 vol% with respect to the total volume of nonvolatile component contained in the magnetic powder composition.

Description

Magnetic powder composition and electronic component

[0001] The present disclosure relates to a magnetic powder composition and an electronic component.

[0002] Magnetic materials including metal magnetic powders and resin compositions are used as raw materials for various industrial products, such as inductors, power supply modules, transformers, reactors, thyristor valves, noise filters (EMI filters), choke coils, motors (cores, rotors, and yokes), electromagnetic wave shields, and solenoid cores (stationary iron cores) for electromagnetic valves (see, for example, Patent Document 1).

[0003] JP 2017-103287 A

[0004] Magnetic materials used in electronic components such as inductors incorporated into smartphones, personal computers, and home appliances are required to have high magnetic permeability and low magnetic loss. Meanwhile, with the recent development of communication devices, there is also a demand for improved voltage conversion efficiency in DC-DC converters, as well as smaller size and higher performance. High-frequency DC-DC converters allow for smaller inductor sizes, enabling the miniaturization of power supply circuits. However, increasing the switching frequency tends to reduce efficiency. Therefore, it is desirable for magnetic materials used in such components to have low magnetic loss in the high-frequency band.

[0005] Therefore, one aspect of the present disclosure aims to provide a magnetic powder composition that has sufficiently high magnetic permeability and small magnetic loss in high frequency bands, and an electronic component obtained using the same.

[0006] In some aspects, the present disclosure provides the following [1] to [6].

[0007] [1] A magnetic powder composition containing a magnetic powder, wherein the magnetic powder comprises (A1) a nanocrystalline magnetic powder having an average particle size of more than 2 μm and less than 5.5 μm, and the content of the nanocrystalline magnetic powder is 60.5 volume % or more based on the total volume of nonvolatile matter in the magnetic powder composition. [2] The magnetic powder composition according to [1], wherein the magnetic powder further comprises (A2) a magnetic powder having an average particle size of 2 μm or less. [3] The magnetic powder composition according to [2], wherein the volume ratio of the (A1) component to the (A2) component [(A1) component / (A2) component] is 1.5 to 20. [4] The magnetic powder composition according to [2], wherein the magnetic powder further comprises (A3) an amorphous magnetic powder having an average particle size of more than 2 μm. [5] The magnetic powder composition according to any one of [1] to [4], wherein the magnetic powder composition further comprises a curable component. [6] An electronic component comprising a cured product of the magnetic powder composition according to [5].

[0008] According to one aspect of the present disclosure, it is possible to provide a magnetic powder composition that has sufficiently high magnetic permeability and small magnetic loss in high frequency bands, and an electronic component obtained using the same.

[0009] In this specification, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. Furthermore, unless specifically stated otherwise, the units of the numerical values ​​before and after "to" are the same. In the numerical ranges described in stages in this specification, the upper or lower limit of a certain numerical range may be replaced with the upper or lower limit of a numerical range of another stage. Furthermore, in the numerical ranges described in this specification, the upper or lower limit of that numerical range may be replaced with a value shown in the examples. Furthermore, the upper and lower limits individually described can be arbitrarily combined. Furthermore, "A or B" may include either A or B, or may include both. Furthermore, unless otherwise specified, the materials exemplified below may be used alone or in combination of two or more. When multiple substances corresponding to each component are present in the composition, the content of each component in the composition means the total amount of the multiple substances present in the composition, unless otherwise specified. In this specification, the term "(meth)acrylate" refers to at least one of an acrylate and its corresponding methacrylate. The same applies to other similar expressions such as "(meth)acryloyl."

[0010] Hereinafter, exemplary embodiments of the present disclosure will be described, but the present disclosure is not limited to the following embodiments.

[0011] <Magnetic Powder Composition> A magnetic powder composition of one embodiment contains (A) a magnetic powder (hereinafter also referred to as "component (A)"), and the magnetic powder contains (A1) a nanocrystalline magnetic powder (hereinafter also referred to as "component (A1)") having an average particle size of more than 2 μm and less than 5.5 μm, and the content of the nanocrystalline magnetic powder is 60.5 vol% or more based on the total volume of the nonvolatile matter in the magnetic powder composition.

[0012] In this specification, the term "nanocrystalline magnetic powder" refers to a magnetic powder containing crystal grains with a particle size of 30 nm or less. The lower limit of the particle size of the crystal grains may be 1 nm or more. The size of the crystal grains can be confirmed, for example, using a TEM (transmission electron microscope). The particles of the nanocrystalline magnetic powder may be polycrystalline. The crystal structure of the crystal grains may be, for example, a bcc crystal structure (body-centered cubic lattice structure), or other crystal structures. The particle size of the nanocrystalline magnetic powder can be measured, for example, by creating a particle size distribution of the magnetic powder on a volume basis using a laser diffraction / scattering particle size distribution analyzer and then using the particle size distribution. The measurement sample can be prepared by dispersing the magnetic powder in pure water using ultrasound.

[0013] The component (A1) may be particles of a magnetic material having a relative magnetic permeability greater than 1. The magnetic material may be an inorganic material, and may be a soft magnetic material or a hard magnetic material.

[0014] Examples of magnetic materials include magnetic metal oxides and magnetic metals. The magnetic material may contain iron (Fe) or may have a composition that further contains one or more elements selected from the group consisting of Cu, Nb, Hf, Zr, Ta, Mo, W, and V in combination with Fe. Specific examples include crystalline iron alloy magnetic materials and crystalline ferrite magnetic materials.

[0015] The magnetic material contained in the component (A1) may be Fe—Si—Nb—B alloy powder, Fe—Si—Nb—B—Cu alloy powder, Fe—Si—B—P—Cu alloy powder, Fe—Co—Zr—B—Cu alloy powder, Fe—Zr—B alloy powder, or Fe—Hf—B alloy powder.

[0016] The component (A1) may be produced by, for example, an atomization method, or a commercially available product. Examples of commercially available magnetic powders include "ATFINE-NC1 PF3FA" (product name: Fe-Si-Nb-B-Cu alloy powder (nanocrystalline magnetic powder), D50 = 3.1 μm) manufactured by Epson Atmix Corporation, and "ATFINE-NC1 PF5FA" (product name: Fe-Si-Nb-B-Cu alloy powder (nanocrystalline magnetic powder), D50 = 4.2 μm) manufactured by Epson Atmix Corporation. If necessary, commercially available magnetic powders may be classified to have an average particle size of more than 2 μm and less than 5.5 μm.

[0017] The component (A1) may be spherical. The aspect ratio of particles of the component (A1) (the value obtained by dividing the length of the major axis by the length of the minor axis) may be 2 or less, 1.5 or less, or 1.2 or less, or may be 1 or more, greater than 1, or 1.05 or more, or may be 1 or more and 2 or less, greater than 1 and 1.5 or less, or 1.05 or more and 1.2 or less.

[0018] The component (A1) may be used alone or in combination of two or more types.

[0019] The content of component (A1) may be 60.5% by volume or more based on the total volume of the nonvolatile content in the magnetic powder composition, which makes it possible to achieve both high magnetic permeability and low magnetic loss in high frequency bands (e.g., 20 MHz or more, 50 MHz or more, or 100 MHz or more).

[0020] From the above viewpoint and from the viewpoint of the fluidity of the magnetic composition, the content of component (A1) may be 60.5 to 80 volume %, 61 to 78 volume %, or 62 to 76 volume %, based on the total volume of the nonvolatile matter in the magnetic powder composition.

[0021] The total amount (mass %) of all magnetic powders in the magnetic powder composition may be 70 mass % or more, 80 mass % or more, or 90 mass % or more, based on the total mass of non-volatile content in the magnetic powder composition, and may be 98 mass % or less, 97.5 mass % or less, or 97 mass % or less, or may be 70 mass % or more and 98 mass % or less, 80 mass % or more and 97.5 mass % or less, or 90 mass % or more and 97 mass % or less.

[0022] The magnetic powder composition according to one embodiment may further include, as the component (A), (A2) a magnetic powder having an average particle size of 2 μm or less (hereinafter also referred to as "component (A2)"). In this case, a densely packed structure can be achieved in which the gaps between the A1 particles are filled with the A2 particles, and an increase in the volume ratio of the magnetic powder in the magnetic composition makes it easier to achieve a high magnetic permeability of the magnetic composition.

[0023] The component (A2) may be an amorphous magnetic powder that does not contain crystal grains, or may be a crystalline magnetic powder whose crystallite size is larger than that of the nanocrystalline magnetic powder.

[0024] Examples of the magnetic material contained in component (A2) include magnetic metal oxide materials and magnetic metal materials, such as iron oxide materials such as iron oxide powder (III) and triiron tetroxide powder, and ferrite-based magnetic materials.

[0025] Examples of ferrite-based magnetic materials include Fe-Mn ferrite, Fe-Mn-Mg ferrite, Fe-Mn-Mg-Sr ferrite, Fe-Mg-Zn ferrite, Fe-Mg-Sr ferrite, Fe-Zn-Mn ferrite, Fe-Cu-Zn ferrite, Fe-Ni-Zn ferrite, Fe-Ni-Zn-Cu ferrite, Fe-Ba-Zn ferrite, Fe-Ba-Mg ferrite, Fe-Ba-Ni ferrite, Fe-Ba-Co ferrite, Fe-Ba-Ni-Co ferrite, and Fe-Y ferrite.

[0026] Examples of magnetic metal materials include crystalline or amorphous alloy magnetic materials such as Fe-Si alloys, Fe-Si-Al alloys, Fe-Cr alloys, Fe-Cr-Si alloys, Fe-Ni-Cr alloys, Fe-Cr-Al alloys, Fe-Ni alloys, Fe-Ni-B alloys, Fe-Si-Ni alloys, Fe-Ni-Mo alloys, Fe-Ni-Mo-Cu alloys, Fe-Co alloys, Fe-Ni-Co alloys, and Co-based amorphous alloys, as well as pure iron.

[0027] The component (A2) may be a commercially available magnetic powder. Specific examples of commercially available magnetic powders include "MZ03S" (trade name, manganese zinc ferrite powder (crystalline magnetic powder), D50=0.2 μm) and "M001" (trade name, manganese ferrite powder (crystalline magnetic powder), D50=0.1 μm), manufactured by Powder Tech Co., Ltd. If necessary, the commercially available magnetic powder may be classified to have an average particle size of 2 μm or less.

[0028] The component (A2) may be spherical. The aspect ratio of particles of the component (A2) (the value obtained by dividing the length of the major axis by the length of the minor axis) may be 2 or less, 1.5 or less, or 1.2 or less, or may be 1 or more, greater than 1, or 1.05 or more, or 1 or more and 2 or less, greater than 1 and 1.5 or less, or 1.05 or more and 1.2 or less.

[0029] The component (A2) may be used alone or in combination of two or more types.

[0030] From the viewpoint of improving magnetic permeability, the content of the component (A2) may be 1 to 30% by volume, or 4 to 20% by volume, based on the total volume of the nonvolatile matter in the magnetic powder composition.

[0031] Furthermore, from the viewpoint of dense packing of the magnetic powder, the volume ratio of the (A1) component to the (A2) component [(A1) component / (A2) component] may be 1.5 to 20, 2.0 to 10, or 6.5 to 17.

[0032] The magnetic powder composition according to one embodiment may further include, as component (A), another magnetic powder in addition to components (A1) and (A2). Examples of the other magnetic powder include an amorphous magnetic powder having an average particle size of more than 2 μm (hereinafter also referred to as “component (A3)”), a nanocrystalline magnetic powder having an average particle size of more than 5.5 μm (hereinafter also referred to as “component (A4)”), and a crystalline magnetic powder having an average particle size of more than 2 μm and a crystallite size of more than 30 nm (hereinafter also referred to as “component (A5)”). These may be used singly or in combination of two or more.

[0033] Examples of the (A3) component include Fe-based amorphous alloy powder. Fe-based amorphous alloys are amorphous powders obtained by rapidly quenching an alloy in which the main component Fe, together with other elements such as Si, is melted at high temperature, and are also known as metallic glasses. Fe-based amorphous alloy powders can be produced according to methods well known in the art. Fe-based amorphous alloy powders are also commercially available. Examples include AW2-08 and KAUMET-6B2 products manufactured by Epson Atmix Corporation, DAPMS3, DAPMS7, DAPMSA10, DAPPB, DAPPC, DAPMKV49, DAP410L, DAP430L, and DAPHYB series products manufactured by Daido Steel Co., Ltd., and MH45D, MH28D, MH25D, and MH20D products manufactured by Kobe Steel, Ltd. These Fe-based amorphous alloy powders may be used alone or in combination of two or more.

[0034] An example of the component (A4) is KUAMET-NC1, a product manufactured by Epson Atmix Corporation.

[0035] Examples of the component (A5) include AKT-PB3Si-45.5Ni, a product of Mitsubishi Steel Corporation, and Manganese Ferrite M-010S, a product of Powder Tech Co., Ltd.

[0036] The contents of the (A3), (A4) and (A5) components may each be 1 vol% or more, 2 vol% or more, or 3 vol% or more, based on the total volume of the nonvolatile content in the magnetic powder composition, from the viewpoint of the magnetic permeability of the magnetic powder composition; 5 vol% or less, 4 vol% or less, or 3 vol% or less, from the viewpoint of low magnetic loss; and 1 to 5 vol% or 2 to 4 vol% from the viewpoint of achieving both magnetic permeability and magnetic loss.

[0037] Furthermore, the total content of the (A3), (A4) and (A5) components may be 1 volume % or more, 2 volume % or more, or 3 volume % or more, based on the total volume of the nonvolatile content in the magnetic powder composition, from the viewpoint of the magnetic permeability of the magnetic powder composition; may be 5 volume % or less, 4 volume % or less, or 3 volume % or less, from the viewpoint of low magnetic loss; and may be 1 to 5 volume % or 2 to 4 volume % from the viewpoint of achieving both magnetic permeability and magnetic loss.

[0038] The magnetic powder composition according to one embodiment may further contain a curable component.

[0039] The curable component may be a resin composition containing a thermosetting resin, a resin composition containing a polymerizable compound and a polymerization initiator, or a combination thereof.

[0040] The thermosetting resin may be at least one resin selected from the group consisting of epoxy resin, phenolic resin, bismaleimide resin, polyimide resin, and polyamideimide resin. The resin composition may further contain other resins (e.g., thermoplastic resins) in addition to the thermosetting resin. For example, the resin composition may further contain at least one other resin selected from the group consisting of polyphenylene sulfide resin, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyethylene terephthalate, and silicone resin.

[0041] For example, epoxy resins (epoxy group-containing compounds) include biphenyl-type epoxy resins, stilbene-type epoxy resins, diphenylmethane-type epoxy resins, sulfur-atom-containing epoxy resins, novolac-type epoxy resins, dicyclopentadiene-type epoxy resins, salicylaldehyde-type epoxy resins, naphthol- and phenol-copolymerized epoxy resins, epoxidized aralkyl-type phenolic resins, bisphenol-type epoxy resins, glycidyl ether-type epoxy resins of alcohols, glycidyl ether-type epoxy resins of paraxylylene-modified phenolic resins and / or metaxylylene-modified phenolic resins, glycidyl ether-type epoxy resins of terpene-modified phenolic resins, cyclopentadiene-type epoxy resins, The epoxy resin may be one or more resins selected from the group consisting of epoxy resins, glycidyl ether type epoxy resins of polycyclic aromatic ring-modified phenolic resins, naphthalene type epoxy resins, glycidyl ether type epoxy resins of naphthalene ring-containing phenolic resins, glycidyl ester type epoxy resins, glycidyl type or methylglycidyl type epoxy resins, alicyclic type epoxy resins, halogenated phenol novolac type epoxy resins, ortho-cresol novolac type epoxy resins, hydroquinone type epoxy resins, trimethylolpropane type epoxy resins, polyfunctional epoxy resins having multiple epoxy groups (trifunctional epoxy resins, tetrafunctional epoxy resins, etc.), and linear aliphatic epoxy resins obtained by oxidizing olefin bonds with a peracid such as peracetic acid.

[0042] The epoxy resin may include a reactive diluent, for example, one or more compounds selected from the group consisting of n-butyl glycidyl ether, versatate glycidyl ether, styrene oxide, ethylhexyl glycidyl ether, phenyl glycidyl ether, butylphenyl glycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, diethylene glycol diglycidyl ether, and trimethylolpropane triglycidyl ether.

[0043] The epoxy resin may include an epoxy group-containing compound that is liquid at 25° C. An epoxy group-containing compound that is liquid at 25° C. means an epoxy group-containing compound having a viscosity of 200 Pa·s or less at 25° C. For example, the epoxy group-containing compound that is liquid at 25° C. may be one or more compounds selected from the group consisting of bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AD ​​type epoxy resins, bisphenol S type epoxy resins, naphthalenediol type epoxy resins, hydrogenated bisphenol A type epoxy resins, and aminoglycidyl ether type epoxy resins.

[0044] The content of the thermosetting resin may be 1.0 to 10.0 mass %, or 2.0 to 8.0 mass %, based on the total mass of nonvolatile matter in the magnetic powder composition.

[0045] The resin composition containing a thermosetting resin may further contain a curing agent and / or a curing accelerator in addition to the thermosetting resin.

[0046] When the resin composition contains an epoxy resin, a curing agent for the epoxy resin (epoxy curing agent) can be further used. Epoxy curing agents are classified into curing agents that cure epoxy resins at low to room temperature, and heat-curing curing agents that cure epoxy resins upon heating. For example, curing agents that cure epoxy resins at low to room temperature include aliphatic polyamines, polyaminoamides, and polymercaptans. For example, heat-curing curing agents include aromatic polyamines, acid anhydrides, phenolic resins, phenolic novolac resins, imidazoles, imidazolines, and dicyandiamide (DICY). From the viewpoint of improving the heat resistance (mechanical strength at high temperatures) of the cured product of the magnetic powder composition, the epoxy curing agent may be a heat-curing curing agent, a phenolic resin, or a phenolic novolac resin.

[0047] The ratio of the hydroxyl group equivalent of the curing agent to the epoxy equivalent of the epoxy resin may be 0.5 or more and 1.5 or less. In other words, the ratio of the active group (phenolic OH group) in the curing agent that reacts with the epoxy group in the epoxy resin may be 0.5 or more and 1.5 or less equivalents per equivalent of epoxy group in the epoxy resin.

[0048] When the resin composition contains an epoxy resin, an epoxy curing accelerator (curing catalyst) may be further used. The curing accelerator (curing catalyst) is not limited as long as it reacts with the epoxy resin to accelerate the curing of the epoxy resin. Examples of the curing accelerator include imidazoles such as alkyl group-substituted imidazoles and benzimidazoles, imidazolines, phosphorus compounds, urea compounds, and tertiary amines. The resin composition may contain one or more curing accelerators.

[0049] The amount of epoxy curing accelerator may be 0.1 to 30 parts by mass per 100 parts by mass of the epoxy resin, from the viewpoint of improving the curability and fluidity of the epoxy resin when absorbing moisture. The content of the epoxy curing accelerator may be 0.001 to 5 parts by mass per 100 parts by mass of the total mass of the epoxy resin and the curing agent (e.g., phenolic resin).

[0050] The resin composition containing a polymerizable compound and a polymerization initiator may be a radical polymerization system. Examples of the polymerizable compound include a compound having a (meth)acryloyl group. Two or more polymerizable compounds may be used in combination.

[0051] The number of (meth)acryloyl groups (number of functional groups) in the compound having a (meth)acryloyl group may be 1 to 10, 1 to 6, or 1 to 4.

[0052] The compound having a (meth)acryloyl group may be, for example, one selected from the group consisting of alkyl (meth)acrylate compounds, hydroxyalkyl (meth)acrylate compounds, and acrylamide compounds, and may be used alone or in combination of two or more.

[0053] The alkyl group of the alkyl (meth)acrylate compound (the portion other than the (meth)acryloyloxy group) may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group may be 1 or more, 3 or more, 5 or more, or 6 or more, and may be 30 or less, 24 or less, 20 or less, 18 or less, 14 or less, or 12 or less. The number of carbon atoms in the alkyl group may be, for example, 1 to 30, 1 to 24, 3 to 18, 5 to 14, or 6 to 12, or 1 to 11, 1 to 8, 1 to 6, or 1 to 4, or 12 to 30, 12 to 28, 12 to 24, 12 to 22, 12 to 18, or 12 to 14.

[0054] The alkyl group of the alkyl(meth)acrylate compound may have a cyclic structure, such as a cycloalkyl group, etc. Examples of alkyl(meth)acrylate compounds having a cyclic alkyl group include cyclohexyl(meth)acrylate, 3,3,5-trimethylcyclohexyl(meth)acrylate, isobornyl(meth)acrylate, terpene(meth)acrylate, and dicyclopentanyl(meth)acrylate.

[0055] The content of the alkyl (meth)acrylate compound may be 5 to 80 mass %, 5 to 70 mass %, or 10 to 60 mass %, based on the total mass of the polymerizable compounds, from the viewpoint of achieving a better balance between the fluidity of the magnetic powder composition and the properties of the cured product.

[0056] The hydroxyalkyl(meth)acrylate compound is a compound in which one or more hydrogen atoms in the above-mentioned alkyl(meth)acrylate compound are substituted with a hydroxy group. Examples of the hydroxyalkyl(meth)acrylate compound include 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 3-hydroxypropyl(meth)acrylate, 2-hydroxybutyl(meth)acrylate, 4-hydroxybutyl(meth)acrylate, 6-hydroxyhexyl(meth)acrylate, 8-hydroxyoctyl(meth)acrylate, 10-hydroxydecyl(meth)acrylate, 12-hydroxylauryl(meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl(meth)acrylate.

[0057] The content of the hydroxyalkyl (meth)acrylate compound may be 5 to 80 mass%, 5 to 70 mass%, or 10 to 60 mass%, based on the total mass of the polymerizable compounds, from the viewpoint of achieving a better balance between the fluidity of the magnetic powder composition and the properties of the cured product.

[0058] Examples of acrylamide compounds include dimethylacrylamide, diethylacrylamide, diisopropylacrylamide, N-(meth)acryloylmorpholine, N-acryloylthiomorpholine, N-acryloyloxazoline, N-acryloylthiazolidine, N-acryloylimidazolidine, N-(meth)acryloylpiperazine, N-vinylpyrrolidone, and N-vinylcaprolactam.

[0059] The content of the acrylamide-based compound may be 5 to 80 mass%, 5 to 70 mass%, or 10 to 60 mass%, based on the total mass of the polymerizable compound, from the viewpoint of achieving a better balance between the fluidity of the magnetic powder composition and the properties of the cured product.

[0060] The resin composition containing a compound having a (meth)acryloyl group may further contain a compound represented by the following formula (1) as the compound having a (meth)acryloyl group.

[0061] In formula (1), R １１ and R １２ each independently represents a hydrogen atom or a methyl group, R １３ represents a divalent group having a poly(meth)acrylate chain.

[0062] The poly(meth)acrylate chain contains a structural unit represented by the following formula (1a):

[0063] In formula (1a), R １４ represents a hydrogen atom or a monovalent organic group, R １５ represents a hydrogen atom or a methyl group.

[0064] R １４The monovalent organic group represented by the formula (I) may be a group having a polar group, for example, a hydrocarbon group, an organic group having an oxygen atom, or an organic group having a nitrogen atom.

[0065] The hydrocarbon group may be linear or may have a ring (for example, an aromatic ring). The number of carbon atoms in the hydrocarbon group may be, for example, 1 or more and 18 or less. Examples of the hydrocarbon group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, a 2-ethylhexyl group, a 2-propylheptyl group, a nonyl group, a decyl group, an isodecyl group, a dodecyl group, an octadecyl group, a phenyl group, a toluyl group, and a benzyl group.

[0066] Examples of organic groups having an oxygen atom include groups having an alkoxy group, groups having a hydroxyl group, groups having a carboxyl group, and groups having a glycidyl group. Examples of groups having an alkoxy group include a 2-methoxyethyl group and a 3-methoxybutyl group. Examples of groups having a hydroxyl group include a 2-hydroxyethyl group, a 2-hydroxypropyl group, and a 4-hydroxybutyl group. Examples of groups having a carboxyl group include a carboxyl group. Examples of groups having a glycidyl group include a glycidyl group.

[0067] Examples of the organic group having a nitrogen atom include a group having an amino group or a nitrile group. An example of the group having an amino group is a 2-aminoethyl group. An example of the group having a nitrile group is a nitrile group.

[0068] The compound represented by formula (1) may be a compound represented by the following formula (1-1).

[0069] In formula (1-1), R １１ and R １２ is R in formula (1) １１ and R １２ and R １４ and R １５ is R in formula (1a)１４ and R １５ and n is an integer of 2 or more (for example, 2 to 1000).

[0070] The viscosity of the compound represented by formula (1) at 23°C is, for example, 5 to 1000 Pa·s, and may be 10 Pa·s or more, 15 Pa·s or more, 20 Pa·s or more, 25 Pa·s or more, 30 Pa·s or more, or 35 Pa·s or more; and may be 800 Pa·s or less, 700 Pa·s or less, 600 Pa·s or less, or 550 Pa·s or less, or may be 10 to 1000 Pa·s, 15 to 800 Pa·s, 20 to 800 Pa·s, 25 to 700 Pa·s, 30 to 600 Pa·s, or 35 to 550 Pa·s.

[0071] The viscosity in this specification refers to a value measured in accordance with JIS Z8803, and specifically refers to a value measured using an E-type viscometer (for example, PE-80L manufactured by Toki Sangyo Co., Ltd.). The viscometer can be calibrated in accordance with JIS Z8809-JS14000.

[0072] The glass transition temperature (Tg) of the compound represented by formula (1) is, for example, −60 to 0° C., and may be −50° C. or higher, or −40° C. or higher, or −10° C. or lower, or −30° C. or lower, or may be −50 to −10° C. or −40 to −30° C. The glass transition temperature means a value measured by differential scanning calorimetry.

[0073] The content of the polymerizable compound may be 1.0 to 10.0 mass %, or 2.0 to 8.0 mass %, based on the total mass of nonvolatile matter in the magnetic powder composition.

[0074] The polymerization initiator may be a thermal radical polymerization initiator. Examples of thermal radical polymerization initiators include azo compounds and organic peroxides. Examples of azo compounds include azobisisobutyronitrile, azobis-4-methoxy-2,4-dimethylvaleronitrile, azobiscyclohexanone-1-carbonitrile, and azodibenzoyl. Examples of organic peroxides include benzoyl peroxide, lauroyl peroxide, di-t-butyl peroxide, di-t-hexyl peroxide, di-t-butylperoxyhexahydroterephthalate, t-butylperoxy-2-ethylhexanoate, 1,1-t-butylperoxy-3,3,5-trimethylcyclohexane, and t-butylperoxyisopropyl carbonate. These may be used alone or in combination of two or more.

[0075] The content of the polymerization initiator may be 0.01 to 10 parts by mass, 0.05 to 7 parts by mass, 0.1 to 5 parts by mass, or 0.5 to 3 parts by mass relative to 100 parts by mass of the polymerizable compound.

[0076] The resin composition containing the polymerizable compound and the polymerization initiator may further contain an antioxidant.

[0077] Examples of the antioxidant include phenol-based antioxidants, benzophenone-based antioxidants, benzoate-based antioxidants, hindered amine-based antioxidants, and benzotriazole-based antioxidants.

[0078] As the antioxidant, a phenolic antioxidant may be used from the viewpoints of heat resistance and low volatility. The phenolic antioxidant has, for example, a hindered phenol structure (hindered phenol ring). The hindered phenol structure (hindered phenol ring) may be, for example, a structure in which t-butyl groups are bonded to one or both of the ortho positions relative to the hydroxyl group on the phenol ring. The phenolic antioxidant has one or more such hindered phenol rings, and may also have two or more, three or more, or four or more such hindered phenol rings.

[0079] Examples of phenolic antioxidants include 2-t-butyl-4-methoxyphenol, 3-t-butyl-4-methoxyphenol, 2,6-di-t-butyl-4-ethylphenol, 2,2'-methylene-bis(4-methyl-6-t-butylphenol), 4,4'-thiobis-(3-methyl-6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, and tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane.

[0080] The content of the antioxidant may be 0.01 to 10 parts by mass, 0.05 to 8 parts by mass, or 0.1 to 5 parts by mass relative to 100 parts by mass of the polymerizable compound.

[0081] The resin composition containing the above-mentioned thermosetting resin and the resin composition containing the polymerizable compound and the polymerization initiator may further contain at least one component selected from the group consisting of a coupling agent, a wax, a rubber, and a flame retardant.

[0082] The coupling agent may be a substance that reacts with a glycidyl group of a thermosetting resin such as an epoxy resin or a (meth)acryloyl group of a compound having a (meth)acryloyl group. The coupling agent improves adhesion between the magnetic powder and the resin composition and improves the mechanical strength of the cured product of the magnetic powder composition. The coupling agent may be a silane-based compound (silane coupling agent). For example, the silane coupling agent may be at least one coupling agent selected from the group consisting of epoxy silane, (meth)acryloyl silane, mercapto silane, amino silane, alkyl silane, ureido silane, acid anhydride silane, and vinyl silane. The resin composition may contain one or more coupling agents.

[0083] Wax may be referred to as a lubricant or a mold release agent. Wax improves the fluidity and moldability of the magnetic powder composition, as well as the mold release properties of the magnetic powder composition. For example, the wax may be at least one compound selected from saturated fatty acids (such as stearic acid, lauric acid, and montanic acid), saturated fatty acid salts (such as metal soaps), and saturated fatty acid esters. The wax may also be a synthetic wax such as polyethylene and polyethylene oxide. The resin composition may contain one or more types of wax.

[0084] The rubber (elastomer) improves the flexibility of a molded body (e.g., a magnetic film) formed from the magnetic powder composition, and the flexibility of a cured product of the molded body. For example, the rubber component may be at least one rubber selected from the group consisting of acrylic rubber, isoprene rubber, butyl rubber, styrene butadiene rubber, butadiene rubber, acrylonitrile butadiene rubber, silicone rubber, urethane rubber, chloroprene rubber, ethylene propylene rubber, fluororubber, vulcanized rubber, epichlorohydrin rubber, and chlorinated butyl rubber. The resin composition may contain one or more rubber components.

[0085] The flame retardant may be at least one compound selected from the group consisting of a bromine-based flame retardant, a phosphorus-based flame retardant, a hydrated metal powder-based flame retardant, a silicone-based flame retardant, a nitrogen-containing compound, a hindered amine compound, an organometallic compound, and an aromatic engineering plastic. The resin composition may contain one or more flame retardants.

[0086] The content of the resin composition in the magnetic powder composition may be 5 to 40 volume %, 10 to 35 volume %, or 25 to 35 volume %, based on the total volume of the nonvolatile content in the magnetic powder composition.

[0087] (Uses of Magnetic Powder Composition) For example, specific industrial products manufactured using the magnetic powder composition may be inductors, power supply modules, transformers, reactors, thyristor valves, noise filters (EMI filters), choke coils, motors (cores, rotors, and yokes), electromagnetic wave shields, and solenoid cores (stationary iron cores) for electromagnetic valves incorporated into electronically controlled fuel injection devices for internal combustion engines.

[0088] The magnetic powder composition of this embodiment has the properties of having sufficiently high magnetic permeability and small magnetic loss in high frequency bands, and can therefore be used as a magnetic material in inductor components in DC-DC converters, which allows for the miniaturization of power supply circuits while maintaining sufficient conversion efficiency.

[0089] The magnetic powder composition can combine the electrical insulation required for a sealing material for electronic components or electronic devices with the soft magnetic properties (electromagnetic wave shielding ability) required for an electromagnetic wave shielding material. Therefore, the magnetic powder composition and its cured product may be used in electronic components or electrical devices as a sealing material that also functions as an electromagnetic wave shielding material. For example, the sealing material that also functions as an electromagnetic wave shielding material may be a sealing material (such as an underfill) for semiconductor packages such as IC packages and LSI packages.

[0090] <Electronic Component> An electronic component of one embodiment includes the cured product of the magnetic powder composition according to one embodiment containing the above-described curable resin component.

[0091] Examples of electronic components include a circuit member including a substrate and a magnetic material that fills gaps between wirings, through holes, blind holes, cavities, or trenches provided in the substrate. In this case, the magnetic material may be a cured product of the magnetic powder composition according to one embodiment, which contains the above-mentioned curable resin component.

[0092] The present disclosure will be described in more detail below using examples and comparative examples, but the present disclosure is not limited to the following examples.

[0093] In the examples and comparative examples, the following components were used.

[0094] [Magnetic powder] Magnetic powder A: "ATFINE-NC1 PF3FA" manufactured by Epson Atmix Corporation (product name: Fe-Si-Nb-B-Cu alloy powder (nanocrystalline magnetic powder), D50 = 3.1 μm) Magnetic powder B: "M001" manufactured by Powder Tech Co., Ltd. (product name: manganese ferrite powder (crystalline magnetic powder), D50 = 0.1 μm) Magnetic powder C: "AW2-08" manufactured by Epson Atmix Corporation (product name: Fe-based amorphous alloy powder, D50 = 3.1 μm)

[0095] [Polymerizable Compounds] Polymerizable compound A: "IBXA" (trade name, isobornyl acrylate, liquid at 25°C) manufactured by Osaka Organic Chemical Industry Ltd. Polymerizable compound B: "ACMO" (trade name, N-acryloylmorpholine, liquid at 25°C) manufactured by KJ Chemicals Corporation Polymerizable compound C: "RC200C" (trade name, compound represented by the above formula (1-1) (R in formula (1-1)) manufactured by Kaneka Corporation １１ and R １２ is a hydrogen atom or a methyl group, and R １４ is a group having a polar group, and R １５ is a hydrogen atom), weight average molecular weight: 18,000, viscosity at 23°C: 530 Pa s, Tg: -39°C, liquid at 25°C)

[0096] [Polymerization initiator] Polymerization initiator: NOF Corporation's "Perbutyl O" (t-butylperoxy-2-ethylhexanoate)

[0097] [Antioxidant] Antioxidant: "Irganox 1010" (trade name, tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane) manufactured by BASF Japan Ltd.

[0098] <Preparation of Resin Composition> A liquid resin composition (varnish) was prepared by stirring and kneading 35 g of IBXA, 35 g of ACMO, and 30 g of RC200C as polymerizable compounds, 1 g of Perbutyl O as a polymerization initiator, and 3 g of Irganox 1010 as an antioxidant using a planetary stirrer.

[0099] <Preparation of Magnetic Powder Composition> (Example 1) Magnetic powder A, magnetic powder B, and a resin composition were stirred and kneaded using a planetary stirrer to obtain the magnetic powder composition of Example 1. The respective contents (unit: volume %) of magnetic powder A, magnetic powder B, and the resin composition (non-volatile content) in the magnetic powder composition were adjusted to the values ​​shown in Table 1 below.

[0100] (Examples 2 to 7 and Comparative Examples 1 to 3) The magnetic powder compositions of Examples 2 to 7 and Comparative Examples 1 to 3 were obtained in the same manner as Example 1, except that the contents (unit: volume %) of magnetic powder A, magnetic powder B, magnetic powder C and resin composition (non-volatile content) were changed as shown in Tables 1 and 2.

[0101] <Evaluation of Magnetic Permeability and Magnetic Loss> The magnetic powder composition was coated onto a PET film support using a squeegee, and a 1 mm thick stainless steel plate was placed around the magnetic powder composition on all four sides. Next, a PET film was placed on top to cover the magnetic powder composition and the stainless steel plate, and the magnetic powder composition was molded and cured into a 1 mm thick plate using a vacuum press (manufactured by Imoto Machinery Co., Ltd., manual hydraulic vacuum heating press, 1A31) under vacuum conditions at 150 °C and 2 MPa for 10 minutes. The magnetic powder composition was then molded and cured into a ring-shaped sample with an outer diameter of 720 mm, an inner diameter of 12 mm, and a thickness of 1 mm. The obtained ring-shaped sample was measured for relative permeability μ' at 20 MHz and magnetic loss coefficient tanδ at 20 MHz, 50 MHz, and 100 MHz using an impedance analyzer. The results are shown in Tables 1 and 2.

[0102] In Example 1 and Comparative Example 1, the integer part of the relative permeability was confirmed, and the magnetic loss coefficient tan δ was confirmed to three decimal places. Furthermore, for all Examples and Comparative Examples, the relative permeability was confirmed to one decimal place, and the magnetic loss coefficient tan δ was confirmed to four decimal places.

[0103]

[0104]

Claims

1. A magnetic powder composition containing a magnetic powder, wherein the magnetic powder comprises (A1) a nanocrystalline magnetic powder having an average particle size of more than 2 μm and less than 5.5 μm, and the content of the nanocrystalline magnetic powder is 60.5 volume % or more based on the total volume of the nonvolatile matter in the magnetic powder composition.

2. The magnetic powder composition according to claim 1, wherein the magnetic powder further comprises (A2) a magnetic powder having an average particle size of 2 μm or less.

3. The magnetic powder composition according to claim 2, wherein the volume ratio of component (A1) to component (A2) [component (A1) / component (A2)] is 1.5 to 20.

4. The magnetic powder composition according to claim 2, wherein the magnetic powder further comprises (A3) amorphous magnetic powder having an average particle size of more than 2 μm.

5. The magnetic powder composition of claim 1, wherein said magnetic powder composition further comprises a curable component.

6. An electronic component comprising a cured product of the magnetic powder composition according to claim 5.

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