TW201929002A - Composite magnetic powder, magnetic resin composition, magnetic resin paste, magnetic resin powder, magnetic resin slurry, magnetic resin sheet, metal foil-attached magnetic resin sheet, magnetic prepreg, and inductor component - Google Patents

Abstract

The present invention addresses the problem of providing a composite magnetic powder that can increase the Q value of a magnetic material at high frequencies. This composite magnetic powder contains a magnetic powder that includes a first powder and a non-magnetic powder that includes a second powder. The first powder comprises an iron-alloy powder. The second powder comprises at least an alumina powder or a silica powder. The average grain diameter of the first powder is less than 5 [mu]m and is 3-30 times the average grain diameter of the second powder.

Description

Composite magnetic powder, magnetic resin composition, magnetic resin paste, magnetic resin powder, magnetic resin slurry, magnetic resin sheet, magnetic resin sheet with metal foil, magnetic prepreg, and inductor parts

The present invention relates to a composite magnetic powder, a magnetic resin composition, a magnetic resin paste, a magnetic resin powder, a magnetic resin slurry, a magnetic resin sheet, a metal foil-attached magnetic resin sheet, a magnetic prepreg, and an inductor part.

2. Description of the Related Art In recent years, with the miniaturization and multi-function of various communication devices such as smart phones and the high-speed calculation processing, the driving frequency has become higher. High-frequency circuits used in such communication devices currently use inductive components.

Regarding the inductance component, Patent Document 1 discloses an inductance component including a coil-shaped wiring and a hardened resin sheet (hereinafter referred to as a magnetic material) covering the coil-shaped wiring. The resin sheet contains an epoxy resin, a phenoxy resin, a linear elastomer, a hardener, and an inorganic filler. The content of the inorganic filler is 80 to 98% by mass based on the total amount of the resin sheet. The content of the linear elastomer is 0.01 to 0.5 parts by mass based on the resin sheet constituents excluding the total of 100 parts by mass of the linear elastomer.

However, a conventional magnetic material as described in Patent Document 1 has a low Q value (quality factor (hereinafter referred to as a Q value) of a magnetic material) showing a low degree of magnetic material loss in a high frequency band (for example, 100 MHz), and the High loss in high frequency band. Inductive parts using such conventional magnetic materials have a large resistance component in the high frequency band, and the Q value of the inductance in the high frequency band (quality factor, Q = 2πfL / R, where L is the inductance and R is the inductance of the inductor) Resistance component, f is frequency) is low. Therefore, there is a concern that inductive component materials such as conventional magnetic materials cannot be used to control high-frequency noise.
Advance technical literature

Patent literature
[Patent Document 1] Japanese Patent No. 5881027

SUMMARY OF THE INVENTION The object of the present invention is to provide a composite magnetic powder, magnetic resin composition, magnetic resin paste, magnetic resin powder, magnetic resin slurry, magnetic resin sheet, Metal foil magnetic resin sheet, magnetic prepreg and inductor parts.

The composite magnetic powder according to one aspect of the present invention includes: a magnetic powder including a first powder and a nonmagnetic powder including a second powder, the first powder is composed of an alloy iron powder, and the second powder is composed of an aluminum oxide powder and silicon oxide At least one of the powders has an average particle diameter of the first powder of less than 5 μm and an average particle diameter of the second powder of 3 times or more and 30 times or less.

A magnetic resin composition according to one aspect of the present invention includes the aforementioned composite magnetic powder; and at least one resin selected from the group consisting of a curable resin and a thermoplastic resin.

The magnetic resin paste according to one aspect of the present invention is the aforementioned magnetic resin composition in a paste form.

The magnetic resin powder according to one aspect of the present invention is a powdery magnetic resin composition.

The magnetic resin slurry according to one aspect of the present invention is the aforementioned magnetic resin composition which further contains a solvent and is in a slurry state.

The magnetic resin sheet according to one aspect of the present invention is the aforementioned magnetic resin composition having a sheet shape.

A magnetic resin sheet with a metal foil according to one aspect of the present invention includes: the magnetic resin sheet; and a metal foil laminated on at least one side of the magnetic resin sheet and having a thickness of 5 μm or less.

A magnetic prepreg according to one aspect of the present invention includes: a fibrous substrate; and the magnetic resin composition or a semi-hardened product of the magnetic resin composition.

An inductor component according to one aspect of the present invention includes an insulating layer of a coiled wiring and a covered coiled wiring, and the insulating layer is formed of a hardened or cured product of the magnetic resin composition.

Embodiments for Implementing the Invention An embodiment of the present invention will be described below.

This embodiment relates to a composite magnetic powder, and more particularly to a composite magnetic powder suitable for use as a magnetic material.
[Composite magnetic powder]

The composite magnetic powder (hereinafter referred to as a composite magnetic powder) of this embodiment contains a magnetic powder and a non-magnetic powder. The magnetic powder includes a first powder. The first powder is made of alloy iron powder. The non-magnetic powder contains a second powder. The second powder is composed of at least one of an alumina powder and a silica powder. The average particle diameter of the first powder is less than 5 μm and is 3 times to 30 times the average particle diameter of the second powder.

The so-called magnetic powder refers to an aggregate of magnetic particles. The non-magnetic powder refers to an aggregate of non-magnetic particles. Hereinafter, the magnetic particles constituting the first powder among the magnetic particles are referred to as large-diameter magnetic particles 10, and the non-magnetic particles constituting the second powder among the non-magnetic particles are referred to as small-diameter non-magnetic particles 20. The so-called magnetic particles are particles composed of a substance (magnetic body) that can be magnetic due to an external magnetic field. Representative substances include iron oxide, chromium oxide, cobalt, and ferrite magnets. The non-magnetic particles are particles that are not contained in the magnetic body (they are not magnetic when an external magnetic field is applied). The "average particle diameter" in this specification means in principle the particle diameter of 50% of the accumulated value in the particle size distribution obtained by the particle size distribution measuring device according to the laser scattering diffraction method, that is, the 50% volume average particle diameter (D ₅₀ ). In the case of fine particles having an average particle diameter of 50 nm or the like, the "average particle diameter" in this specification means an average particle diameter measured by observation with a scanning electron microscope (SEM).

The composite magnetic powder can be suitably used as a raw material of a magnetic material for an inductive component (hereinafter referred to as a high-frequency inductive component) that suppresses high-frequency noise. High-frequency inductive parts can be evaluated by the Q value of the magnetic material. The higher the Q value of the magnetic material, the less the loss of the magnetic material, and the smaller the resistance component R of the inductor. Therefore, the higher the Q value of the inductor, the higher the performance of the high frequency inductive component. When functioning as a high-frequency inductive component, the Q value of the magnetic material at 100 MHz needs to be 20 or more, and from the viewpoint of high-performance high-frequency inductive components, it is preferably 33 or more. The high frequency band refers to tens of MHz or more and several GHz or less. The magnetic material refers to a cured product of a first magnetic resin composition described later or a cured product of a second magnetic resin composition described later. The Q value of the magnetic material can be determined in the same manner as the method (RF impedance analyzer) described in the embodiment.

The Q value of magnetic materials is the loss coefficient (tanδ) expressed by the real part (μ ') and the imaginary part (μ ") of complex permeability (μ = μ'-i × μ", where i is an imaginary unit). = μ "/ μ ') (1 / tanδ = μ' / μ"). The real number part (μ ') and the imaginary number part (μ ") are frequency dependent, and the Q value of the magnetic material is also frequency dependent. Specifically, once it reaches a certain frequency, the imaginary number part (μ") It will increase sharply, while the real number part (μ ') tends to decrease. From the formula of Q value of magnetic material = μ '/ μ ", it is clear that when you want to increase the Q value of magnetic material at 100MHz, the real part (μ') at 100MHz should be high and the imaginary part (μ") should be low. . In designing high-frequency inductance parts, the real number part (µ ') at 100 MHz should be 6.0 or more.

In this embodiment, the average particle diameter of the first powder is 3 times to 30 times the average particle diameter of the second powder. As a result, the imaginary part (μ ") is lower at 100MHz, which can make the Q value of the magnetic material reach 20 or more. The main reason is presumed that the adjacent large-diameter magnetic particles 10 and 10 are not easy to agglomerate each other, and the adjacent large-diameter The electrical insulation properties of the magnetic particles 10 and 10 are ensured. Specifically, as shown in FIG. 1A for the magnetic material before processing, each of the large-diameter magnetic particles 10 is uniformly arranged around a large number of small-diameter non-magnetic particles. The magnetic particles 20 and the large-diameter magnetic particles 10 are easy to form a layer 21 composed of the small-diameter non-magnetic particles 20. In this way, each large-diameter magnetic particle 10 can function as an independent particle, so that the adjacent large-diameter magnetic particles can function. The interval I between 10 and 10 is optimized. In other words, as shown in FIG. 1B, most of the large-diameter magnetic particles 10 and 10 that are close to each other cannot easily function as a large-scale particle 11 in appearance. Further, because The second powder is composed of at least one of alumina powder and silicon oxide powder, so the layer 21 is insulating. Therefore, eddy currents between particles flowing across adjacent large-diameter magnetic particles 10 are unlikely to occur and can be advanced. Reduce the eddy current loss by one step. It is speculated that the imaginary part (μ ") at 100 MHz is therefore reduced. The so-called magnetic material before treatment refers to a state before the magnetic material is hardened or cured, and includes a first magnetic resin composition before hardening, a magnetic resin paste described later, a magnetic resin powder described later, a resin magnetic paste described later, and a resin described later. A magnetic resin sheet and a second magnetic resin composition before curing.

If the composite magnetic powder is a mixed powder containing the first powder and the second powder, it may further contain a powder different from the first powder and the second powder. That is, in the particle size distribution measured by converting the volume of the composite magnetic powder, at least two peaks indicating the presence frequency may be present, and the peaks may be three or more.

The shape of the magnetic particles and non-magnetic particles constituting the composite magnetic powder is not particularly limited, and examples thereof include a spherical shape, an ellipsoid shape, a flat shape, and a broken shape. The shapes of the magnetic particles and non-magnetic particles may be all the same or different from each other. Among them, the shape of each magnetic particle and non-magnetic particle is preferably spherical. If the shape of each magnetic particle and non-magnetic particle is spherical, the filling amount of the composite magnetic powder to the magnetic material can be increased. In addition, as for the magnetic material before the treatment in which the shape of each magnetic particle and the non-magnetic particle are spherical and the magnetic material before the treatment in which the shape of each magnetic particle and the non-magnetic particle are not all spherical, the composite magnetic powder When the filling amount of the magnetic material before the treatment is the same, the flowability of the magnetic material before the treatment is better. It can further improve the Q value of magnetic materials at 100MHz.

Spherical includes those having an average sphericity of 0.7 or more. The average sphericity can be determined as follows. The respective particle images of each magnetic particle are taken with a scanning electron microscope or the like, and each particle image is input to an image analysis device or the like, and the projected area (S) and the peripheral length (L) of each magnetic particle are measured from the photograph. Next, the measurement result is substituted into the following formula to calculate the sphericity.
Sphericity = 4πS / L ²

In this way, a sphericity of a certain number of particles (preferably 200 or more) is obtained for each magnetic particle, and the average value is the average sphericity.
{Magnetic powder}

The composite magnetic powder contains a magnetic powder. The magnetic powder includes a first powder, and may further include other magnetic powders.

Magnetic powder should be treated with insulation. That is, the surface of each magnetic particle should be covered with an electrically insulating film. Thereby, the imaginary part (μ ") can be lowered at 100MHz and the Q value of the magnetic material can be made higher. The electrical insulation reliability of the magnetic material itself can be further improved. As for the imaginary part at 100MHz ( μ ”) The lower reason is presumed to be that the eddy current between particles flowing across adjacent magnetic particles is not easy to occur through the insulating coating, which can further reduce the eddy current loss.

Examples of the method for the insulation treatment include a method of mixing a magnetic powder with an aqueous solution containing an electrically insulating filler and drying the same. As the material of the electrically insulating filler, phosphoric acid, boric acid, and magnesium oxide can be used. This electrically insulating film is different from the layer 21 made of small-diameter nonmagnetic particles 20. When the magnetic particles themselves are electrically insulating, they may not be covered with an electrically insulating film.

The mixing ratio of the magnetic powder is preferably 4.0 parts by mass or more and 19.0 parts by mass relative to 1 part by mass of the non-magnetic powder, more preferably 4.0 parts by mass or more and 5.7 parts by mass or less, and more preferably 4.3 parts by mass or more and 5.2 parts by mass or less. If the mixing ratio of the magnetic powder is within the above range, the Q value of the magnetic material at 100 MHz and the fluidity of the magnetic material before processing can be balanced. This is presumably because, as shown in FIG. 1A, the thickness of the layer 21 composed of the non-magnetic particles 20 arranged around the large-diameter magnetic particles 10 can be made thin, and the interval I can be more easily optimized.
(First powder)

The first powder is composed of an alloyed iron powder. The alloy iron powder is an aggregate of alloy iron particles. The material of the alloy iron particles is an alloy mainly composed of iron. The material of the alloy iron particles may include, for example, aluminum-silicon-iron powder (Sendust), Permendur, silicon steel, permalloy, and Fe-Si-Cr alloy. These are alloyed irons with high magnetic permeability.

Al-Si-Fe powder is an alloy (Fe-Si-Al alloy) composed of iron, silicon, and aluminum. Al-Si-Fe powder has high saturation magnetic flux density and magnetic permeability, small iron loss, and excellent abrasion resistance. An example of the composition of alumino-silicon powder is Fe-9.5Si-5.5Al (the value is mass%, and the remainder is Fe). Near this composition region, the magnetostrictive constant and the magnetic anisotropy constant are almost zero at the same time. Therefore, high magnetic permeability and low coercive force can be obtained. Bormentur iron-cobalt alloy is an alloy mainly composed of iron and cobalt. Bormentur iron-cobalt alloy has the largest saturation magnetic flux density among soft magnetic materials that have been put into practical use. An example of the composition of the Bormentur iron-cobalt alloy is Fe-49Co-2V (the value is mass%, and the remainder is Fe). Silicon steel is an alloy made by adding a small amount of silicon to iron. Because silicon steel does not contain carbon, it is also called ferrosilicon. The high magnetic permeability alloy is a Ni-Fe alloy. High-permeability alloys are also referred to as high-permeability alloy A, high-permeability alloy B, high-permeability alloy C, and high-permeability alloy D under the JIS standard.

The average particle diameter of the first powder is 3 times to 30 times, preferably 3.5 times to 20 times, and more preferably 4 times to 15 times. If the average particle diameter of the first powder is less than three times the average particle diameter of the second powder, the imaginary part (µ '') at 100 MHz may increase and the Q value of the magnetic material may be less than 20. It is presumed that the increase in the imaginary part (μ ″) at 100 MHz is because the layer 21 made of the small-diameter nonmagnetic particles 20 is not easily formed on the surface of the large-diameter magnetic particles 10 as shown in FIG. 1C. If the average particle diameter of the first powder is larger than 30 times the average particle diameter of the second powder, the real number part (µ ') at 100 MHz may decrease and the Q value of the magnetic material may be less than 20. It is presumed that the reduction of the real number part (μ ′) at 100 MHz is because, as shown in FIG. 1D, the layer 21 composed of the small-diameter nonmagnetic particles 20 is easily formed on the surface of the large-diameter magnetic particles 10 and the adjacent large-diameter magnetic particles 10 and 10 are adjacent to each other. The interval I is widened for the sake of reason. When the first powder is a mixed powder obtained by mixing two or more kinds of powders having different average particle diameters, the average particle diameter of the first powder refers to the average particle diameter of the mixed powder. In addition, when the second powder is a mixed powder obtained by mixing two or more kinds of powders having different average particle diameters, the same principle applies. The average particle diameter of the second powder refers to the average particle diameter of the mixed powder.

The average particle diameter of the first powder is less than 5 μm, preferably 0.05 μm or more and less than 5 μm, and more preferably 0.5 μm or more and less than 5 μm. If the average particle diameter of the first powder is 5 μm or more, the imaginary part (μ ”) at 100 MHz will increase and the Q value of the magnetic material may be less than 20.

The content of the first powder may be appropriately adjusted depending on the material and average particle size of other magnetic powders. It is preferably 20 mass% or more and 100 mass% or less, more preferably 40 mass% or more and 100 mass% relative to the total mass of the magnetic powder. the following. If the content of the first powder is within the above range, the magnetic material can maintain a high Q value at 100 MHz, and the real number part (μ ′) can be further improved.
(Other magnetic powder)

The magnetic powder may contain other magnetic powder than the first powder. The other magnetic powder is an aggregate of other magnetic particles different from the large-diameter magnetic particles 10.

As for the material of other magnetic particles, for example, pure iron, metal oxides, alloys, and resins can be used. Pure iron is high-purity iron with 99.90 mass% or more and 99.95 mass% or less. Specific examples of the pure iron include carbonyl iron, yam iron, sponge iron, and electrolytic iron. Iron carbonyl can be obtained by thermal decomposition of iron carbonyl Fe (CO) ₅ . Examples of the metal oxide include ferrite magnets and magnetite. Ferrite magnets are a general term for ceramics with iron oxide as the main component and have insulation properties. As the alloy, for example, nickel, a cobalt-based alloy, or the like can be used. Among them, as for the material of other magnetic particles, a ferrite magnet is preferably used. By including a ferrite magnet in the magnetic material, the real part (μ ') at 100 MHz can be further improved.

Ferrite magnets can be either ferrite soft magnets showing soft magnetic properties or ferrite hard magnets showing strong magnetic properties. Examples of the crystalline structure of the ferrite magnet include spinel ferrite magnets, hexagonal ferrite magnets, and garnet ferrite magnets.

Spinel ferrite magnets have a spinel-type crystal structure, and the composition formula is expressed by MeO · Fe ₂ O ₃ or MeFe ₂ O ₄ (Me: transition metals such as Zn, Ni, Cu, Mn, Mg, and Co). The majority of spinel ferrite magnets are ferrite soft magnets. Specific examples include manganese magnesium ferrite magnets, manganese zinc ferrite magnets, nickel zinc ferrite magnets, and copper zinc ferrite magnets. Because the spinel ferrite magnet has high magnetic permeability and high resistance, the eddy current loss in the high frequency region is small, so it is very effective as an inductive part for high frequency circuits.

Hexagonal ferrite magnets have a hexagonal crystal structure of a magnetite type. The composition formula is represented by MO · 6Fe ₂ O ₃ or MFe ₁₂ O ₁₉ (M: alkaline earth metals such as Ba, Sr, Pb). Hexagonal ferrite magnets are also referred to as magnetite-type ferrite magnets and M-type ferrite magnets. Compared to spinel ferrite magnets, hexagonal ferrite magnets have a larger magnetic anisotropy, so they are representative ferrite hard magnets that exhibit greater coercive force. Specific examples include a barium ferrite magnet and a strontium ferrite magnet.

Garnet ferrite magnets have a garnet-type crystal structure, and the composition formula is represented by 3R ₂ O ₃ · 5Fe ₂ O ₃ or R ₃ Fe ₅ O ₁₂ (R: rare earth elements such as Y, Sm, and Gd). Garnet ferrite magnets are also called RIG (Rare-earth Iron Garnet, rare earth iron garnet). Representative is YIG (Yttrium Iron Garnet, yttrium iron garnet). Garnet ferrite magnets have low magnetic loss in the high frequency region, so they are very effective as microwave inductor parts.

The average particle diameter of other magnetic powders is not particularly limited, and is preferably 0.05 μm or more and 5 μm or less, and more preferably 0.5 μm or more and 5 μm or less. If the average particle diameter of other magnetic particle diameters is within the above range, the imaginary part (μ) at 100 MHz can be made lower.

The mixing ratio of other magnetic powders can be adjusted appropriately depending on the average particle size of other magnetic powders. When the average particle diameter of the other magnetic powder is 0.02 μm or more and 0.1 μm or less, the mixing ratio of the other magnetic powder is preferably less than 12% by mass, and more preferably 0.5% by mass or more and 10% by mass or less with respect to the first powder. If the average particle diameter of other magnetic powders is within the above range and its mixing ratio is within the above range, the magnetic material sheet obtained at 100 MHz can have a Q value of 20 or more while the obtained magnetic resin sheet has excellent fluidity.
{Non-magnetic powder}

The composite magnetic powder contains a non-magnetic powder. The non-magnetic powder includes a second powder, and may further include other non-magnetic powder.
(Second powder)

The second powder is at least one of a silicon oxide powder and an alumina powder. That is, the structure of the second powder is as follows: a structure consisting only of silicon oxide powder, a structure consisting of only alumina powder, or a structure consisting of silicon oxide powder and alumina powder. Both the silicon oxide powder and the alumina powder have high electrical insulation properties, so the eddy current flow can be suppressed by the second powder.

Silica powder is a collection of silica particles. As the silica particles, for example, crystalline silica particles and amorphous silica particles can be used. The silicon oxide particles may be porous.

Alumina powder is an aggregate of alumina particles. Examples of the material of the alumina particles include α-alumina, γ-alumina, δ-alumina, θ-alumina, η-alumina, and κ-alumina.

The average particle diameter of the second powder is adjusted in accordance with the average particle diameter of the first powder, etc., so that the average particle diameter of the first powder will be 3 times to 30 times the average particle diameter of the second powder, preferably 0.05 μm or more and 5 μm or less, more preferably 0.5 μm or more and 2 μm or less. If the average particle diameter of the second powder is within the above range, it is easy to ensure the fluidity of the magnetic material before processing.

The content of the second powder only needs to be adjusted appropriately according to the material and average particle size of other non-magnetic powders. It is preferably 50% by mass or more and 100% by mass or less, more preferably 70% by mass relative to the total mass of the non-magnetic powder. % To 100% by mass.
(Other non-magnetic powder)

The non-magnetic powder may further contain other non-magnetic powder. The other non-magnetic powder is an aggregate of other non-magnetic particles different from the small-diameter non-magnetic particles 20.

Examples of the material of other nonmagnetic particles include carbon black, titanium oxide, cerium oxide, tin oxide, tungsten oxide, ZnO, ZrO ₂ , SiO ₂ and Cr ₂ O ₃ .

Other non-magnetic powders should be electrically insulating. That is, it is desirable that the surface of other non-magnetic particles is covered with an electrically insulating film. Examples of the method for the insulation treatment include a method of mixing a nonmagnetic powder with an aqueous solution containing an electrically insulating filler and drying the same. Examples of the material for the electrically insulating filler include phosphoric acid, boric acid, and magnesium oxide. When other non-magnetic particles are electrically insulating, they may not be coated with an electrically insulating film. The average particle diameter of the other non-magnetic powder is not particularly limited, and may be equal to the average particle diameter of the second powder.
[Magnetic resin composition]

The magnetic resin composition according to this embodiment includes: a composite magnetic powder; and at least one resin selected from the group consisting of a curable resin and a thermoplastic resin. The magnetic resin composition may be a resin composition containing a curable resin (hereinafter referred to as a first magnetic resin composition) or a resin composition containing a thermoplastic resin (hereinafter referred to as a second magnetic resin composition).

The Q value of the hardened or cured product of the magnetic resin composition at a frequency of 100 MHz is preferably 20 or more. That is, the Q value of the hardened product of the first magnetic resin composition at a frequency of 100 MHz is preferably 20 or more, and the Q value of the cured product of the second magnetic resin composition at a frequency of 100 MHz is preferably 20 or more. In this case, the magnetic resin composition can be suitably used as a magnetic material for high-frequency inductance parts. The Q value of the hardened or cured product of the magnetic resin composition at a frequency of 100 MHz is more preferably 33 or more.
{First Magnetic Resin Composition}

The first magnetic resin composition contains a composite magnetic powder and a curable resin.

The first magnetic resin composition contains a curable resin. Examples of the curable resin include a thermosetting resin and a photocurable resin. The first magnetic resin composition may include only a thermosetting resin or only a photocurable resin, or may include both a thermosetting resin and a photocurable resin.

The photocurable resin is a reactive compound that can absorb light and initiate a crosslinking reaction. The photo-curable resin is not particularly limited, and it only needs to be a photo-curable resin. The photo-curable resin is, for example, a resin having an unsaturated polymerizable group. Examples of the photocurable resin include a methacrylic resin, an acrylic resin, an epoxy resin, and an epoxy resin. There may be only one type of photocurable resin contained in the first magnetic resin composition, or two or more types. The photocurable resin may be liquid or solid such as powder at normal temperature.

Examples of the methacrylic resin include a methacrylate, a polymethacrylate, and an ethylene-methacrylic copolymer.

Examples of the acrylic resin include an ethylene-acrylic acid copolymer, an ethylene-methyl acrylate copolymer, an acrylate, and a polyacrylate.

The epoxy resin may be a monofunctional epoxy resin having one epoxy group in one molecule, or a polyfunctional epoxy resin having two or more epoxy groups in one molecule. Examples of the polyfunctional epoxy resin include: polybutadiene epoxy resin, bisphenol A epoxy resin, and bisphenol F epoxy resin, and other bisphenol epoxy compounds; naphthalene epoxy compounds, and aliphatic epoxy resins. Compounds, biphenyl type epoxy compounds, epoxy amine type epoxy compounds, hydrogenated bisphenol A type epoxy compounds, and other alcohol type epoxy compounds; epoxy modified polysiloxane, phenol novolac type epoxy compounds, and cresol Phenolic epoxy compounds such as phenolic epoxy compounds; alicyclic epoxy compounds; heterocyclic epoxy compounds; polyfunctional epoxy compounds; epoxypropyl ether epoxy compounds; epoxypropyl ester rings Oxygen compounds; halogenated epoxy compounds such as brominated epoxy compounds; rubber modified epoxy compounds; urethane modified epoxy compounds; epoxidized polybutadiene; epoxidized styrene-butadiene-styrene Block copolymer; epoxy-containing polyester compound; epoxy-containing polyurethane compound; and epoxy-containing acrylic compound. These epoxy resins may be used alone or in combination of two or more.

Oxygen resin can be used alone or in combination of two or more.

When the first magnetic resin composition contains a photocurable resin, the first magnetic resin composition may contain a photopolymerization initiator as necessary. Examples of the photopolymerization initiator include a photoradical generation initiator and a photoacid generation initiator. When the first magnetic resin composition contains at least one of a methacrylic resin and an acrylic resin, the first magnetic resin composition preferably contains a photo radical generating initiator. The photo-radical generation initiator is not particularly limited, and it is only necessary to make a photo-polymerization reaction by generating free radicals. In addition, when the first magnetic resin composition contains at least one of an epoxy resin and an epoxy resin, the first magnetic resin composition preferably contains a photoacid generation initiator. The photoacid generation initiator is not particularly limited, and may be an ionic photoacid generation initiator or a nonionic photoacid generation initiator.

The first magnetic resin composition preferably contains a thermosetting resin. A thermosetting resin is a reactive compound that can initiate a crosslinking reaction by heat. Examples of thermosetting resins include bisphenol A epoxy resin, bisphenol F epoxy resin, polyfunctional epoxy resin, biphenyl epoxy resin, cresol novolac epoxy resin, and novolac epoxy resin. Epoxy resin and fluorene imine resin. A polyfunctional epoxy resin is a resin having three or more epoxy groups in one molecule. The first magnetic resin composition may contain only one thermosetting resin or two or more thermosetting resins. The thermosetting resin may be in a liquid state or a solid state such as a powder at normal temperature. The content of the thermosetting resin is preferably 75% by mass or more and 100% by mass or less with respect to the total mass of the resin component in the first magnetic resin composition.

When the first magnetic resin composition contains a thermosetting resin, the first magnetic resin composition may further contain a curing agent. The hardener is an additive that hardens a thermosetting resin. Examples of the hardening agent include dicyandiamide, a phenol-based hardener, cyclopentadiene, an amine-based hardener, and an acid anhydride. The phenolic hardener has two or more phenolic hydroxyl groups in one molecule. Examples of the phenol-based hardener include phenol novolac, phenol aralkyl resin, naphthalene-type phenol resin, and bisphenol resin. Examples of the bisphenol resin include bisphenol A resin and bisphenol F resin. The hardener can be liquid or solid at normal temperature. The content of the hardener is preferably 20% by mass or less based on the total mass of the resin component of the first magnetic resin composition.

When the first magnetic resin composition contains a thermosetting resin, the first magnetic resin composition may further contain a hardening accelerator. Examples of the hardening accelerator include tertiary amines, tertiary amine salts, imidazole, phosphine, and phosphonium salts. As the imidazole, 2-ethyl-4-methylimidazole or the like can be used. The content of the hardening accelerator may be appropriately adjusted depending on the materials of the thermosetting resin and the hardener.

The first magnetic resin composition may further contain a thermoplastic resin. Thereby, it is possible to provide the magnetic resin sheet 1 described later with bending followability, elasticity, and the like. As the thermoplastic resin, a phenoxy resin or the like can be used. The content of the thermoplastic resin relative to the total mass of the resin component of the first magnetic resin composition is preferably 2% by mass or more and 50% by mass or less.

The first magnetic resin composition may further contain a surface treatment agent. Examples of the surface treatment agent include a silane coupling agent and a dispersant. As the silane coupling agent, for example, 3-glycidoxypropyltriethoxysilane can be used. Examples of the dispersant include higher fatty acid phosphates, amine salts of higher fatty acid phosphates, and alkylene oxides of higher fatty acid phosphates. As the higher fatty acid phosphate, octyl phosphate, decyl phosphate, and lauryl phosphate can be used. The content of the surface treatment agent is preferably 0% by mass or more and 30% by mass or less with respect to the total mass of the resin component of the first magnetic resin composition.

The first magnetic resin composition may further include an elastomer. Accordingly, if the first magnetic resin composition contains an elastomer, elasticity of the hardened rubber of the first magnetic resin composition can be imparted. Examples of the elastomer include thermosetting elastomers and thermoplastic elastomers.

The first magnetic resin composition may further contain a solvent. Methyl ethyl ketone (MEK), N, N-dimethylformamide (DMF), acetone, and methyl isobutyl ketone (MIBK) can be used. The solvent may be used singly or in combination of two or more kinds. When two or more solvents are mixed, the mixing ratio (mass ratio and volume ratio) is not particularly limited.

The content of the composite magnetic powder is preferably 70% by mass or more of the solid content of the first magnetic resin composition, more preferably 75% by mass or more, and more preferably 80% by mass or more. If the content of the composite magnetic powder is 70% by mass or more of the solid content of the magnetic resin composition as a whole, the real number part (µ ') at 100MHz is likely to be 6.0 or more, and a high-frequency inductor can be easily designed well. In addition, the content of the composite magnetic powder is preferably 99.5% by mass or less, more preferably 99% by mass or less, and most preferably 98.5% by mass or less, of the solid content of the first magnetic resin composition. If the content of the composite magnetic powder is less than 99.5% by mass of the solid content of the magnetic resin composition as a whole, the Q value of the magnetic material is likely to increase. Here, the solid content of the magnetic resin composition refers to the amount of the solvent deducted from the magnetic resin composition.

The method for preparing the first magnetic resin composition includes, for example, a method of mixing the composite magnetic powder with a curable resin, and a hardener, a hardening accelerator, a thermoplastic resin, a surface treatment agent, and an elastomer as required.

As described later, since the first magnetic resin composition can be in any of paste, slurry, powder, and sheet forms, the first magnetic resin composition in a suitable form can be used in accordance with subsequent steps. The subsequent steps include, for example, a step of injection molding using a mold and a step of embedding molding after heating and pressing.
{Second magnetic resin composition}

The second magnetic resin composition (hereinafter referred to as the second magnetic resin composition) contains a composite magnetic powder and a thermoplastic resin.

A thermoplastic resin is a compound that can be softened by heating to a glass transition temperature or melting point and can be cured by cooling to a temperature below the glass transition temperature or melting point. Examples of the thermoplastic resin include nylon. For example, nylon 6 can be used.

The second magnetic resin composition may further contain a curable resin. This makes it possible to impart good strength to the magnetic resin sheet 1 described later. As the curable resin, a curable resin that can be contained in the first magnetic resin composition can be used. The content of the curable resin is preferably 2% by mass or more and 50% by mass or less with respect to the total mass of the resin component of the second magnetic resin composition.

The second magnetic resin composition may further contain a surface treatment agent. Examples of the surface treatment agent include a silane coupling agent and a dispersant. As the silane coupling agent, for example, 3-glycidoxypropyltriethoxysilane can be used. Examples of the dispersant include higher fatty acid phosphates, amine salts of higher fatty acid phosphates, and alkylene oxides of higher fatty acid phosphates. As the higher fatty acid phosphate, octyl phosphate, decyl phosphate, and lauryl phosphate can be used. The content of the surface treatment agent is preferably 0% by mass or more and 30% by mass or less with respect to the total mass of the resin component of the second magnetic resin composition.

The second magnetic resin composition may further include an elastomer. This makes it possible to impart elasticity to the hardened rubber of the second magnetic resin composition. Examples of the elastomer include thermosetting elastomers and thermoplastic elastomers. The content of the elastomer may be appropriately adjusted depending on the use application of the second magnetic resin composition and the like.

The second magnetic resin composition may further contain a solvent. Examples of the solvent include methyl ethyl ketone (MEK), N, N-dimethylformamide (DMF), acetone, and methyl isobutyl ketone (MIBK). The solvent may be used singly or in combination of two or more kinds. When two or more solvents are mixed, the mixing ratio (mass ratio and volume ratio) is not particularly limited.

The content of the composite magnetic powder is preferably 70% by mass or more of the solid content of the second magnetic resin composition as a whole, more preferably 75% by mass or more, and more preferably 80% by mass or more. If the content of the composite magnetic powder is 70% by mass or more of the solid content of the magnetic resin composition as a whole, the proportion of the composite magnetic powder in the second magnetic resin composition is increased, and a cured product with high complex magnetic permeability can be obtained. In addition, the content of the composite magnetic powder is preferably 99.5% by mass or less, more preferably 99% by mass or less, and most preferably 98.5% by mass or less, of the solid content of the second magnetic resin composition. If the content of the composite magnetic powder is less than 99.5% by mass of the solid content of the magnetic resin composition as a whole, the fluidity of the second magnetic resin composition can be ensured during molding, and a cured product with high complex magnetic permeability can be obtained. Here, the solid content of the magnetic resin composition refers to the amount of the solvent deducted from the magnetic resin composition.

As a method for adjusting the second magnetic resin composition, for example, a method of melt-kneading a composite magnetic powder, a thermoplastic resin, and an elastomer as necessary is introduced into the kneader. As a kneader, a screw extruder, a kneader, a Banbury mixer, a biaxial kneading extruder, etc. can be used, for example. The obtained second magnetic resin composition may be further formed into a desired shape. Examples of the method for forming the second magnetic resin composition include extrusion molding and injection molding.

As described later, since the second magnetic resin composition can be in any of paste, paste, powder, and sheet shapes, the second magnetic resin composition in an appropriate form can be used in the subsequent steps. The subsequent steps include, for example, a step of injection molding using a mold and a step of embedding molding after heating and pressing.
[Magnetic resin paste]

The magnetic resin composition of the magnetic resin paste (hereinafter referred to as a magnetic resin paste) of this embodiment is in a paste form. Paste means that the magnetic resin composition is fluid at room temperature. The magnetic resin composition may be a first magnetic resin composition or a second magnetic resin composition. That is, the magnetic resin paste may be paste-like in the first magnetic resin composition, or may be paste-like in the second magnetic resin composition.

The filling rate of the magnetic powder in the magnetic resin paste (hereinafter referred to as the magnetic powder content) is preferably 20 vol% or more and 99 vol% or less, more preferably 53 vol% or more and 95 vol% or less, relative to the solid content of the magnetic resin paste. If the content of the magnetic powder is within the above range, the real number part (µ ') at 100 MHz can be increased, and the fluidity of the magnetic resin paste can be easily controlled. The calculation method of the magnetic powder content is calculated from the blending amount of each material and the specific gravity of each material constituting the solid content of the magnetic resin paste. In the magnetic resin paste, when the magnetic resin composition contains a solvent, the solid content of the magnetic resin paste refers to the amount of the solvent deducted from the magnetic resin composition.

As for the method for preparing the magnetic resin paste, for example, at least one liquid-type resin selected from the group consisting of a curable resin and a thermoplastic resin is used, and the composite magnetic powder, the liquid-type resin, and the A method of mixing a hardening agent, a hardening accelerator, a surface treatment agent, an elastomer, etc., as required. In addition, when the magnetic resin composition contains a solvent in the magnetic resin paste, for example, at least one resin selected from the group consisting of a curable resin and a thermoplastic resin can be dissolved in the solvent to obtain a resin solution, and A magnetic resin paste is prepared by mixing a composite magnetic powder and a hardener, a hardening accelerator, a surface treatment agent, an elastomer, and the like as required in the obtained resin solution.

The magnetic resin paste may be a solvent-containing paste or a solvent-free paste. That is, the first magnetic resin composition may be in a solvent-containing paste state or a solvent-free paste state. In addition, the second magnetic resin composition may have a solvent-containing paste or a solvent-free paste.

The magnetic resin paste is preferably a paste containing no solvent in the magnetic resin composition. At this time, an environmentally friendly magnetic resin paste can be prepared without using a solvent. In addition, since the magnetic resin paste does not contain a solvent, voids can be prevented when the magnetic resin paste is stored or when heated. Furthermore, when the magnetic resin paste is used, the risk of contamination of parts or machines used with the magnetic resin paste caused by the solvents contained in the magnetic resin paste can be reduced. In addition, when the magnetic resin paste is made to contain a solvent, special steps and an explosion-proof correspondence of a device may be required during the manufacturing process. However, the manufacturing process can be simplified by making the magnetic resin paste solvent-free.

As for the magnetic resin paste, when the magnetic resin composition is a paste containing a solvent, the content of the solvent contained in the magnetic resin composition should preferably be 5 mass% or less, more preferably 1 mass% of the solid content of the magnetic resin composition as a whole. Below, it is particularly preferably 0.5% by mass or less.

Examples of the solvent include methyl ethyl ketone (MEK), N, N-dimethylformamide (DMF), acetone, and methyl isobutyl ketone (MIBK). The solvent may be used singly or in combination of two or more kinds. When two or more solvents are mixed, the mixing ratio (mass ratio and volume ratio) is not particularly limited.
[Magnetic resin powder]

The magnetic resin composition of the magnetic resin powder (hereinafter referred to as magnetic resin powder) in this embodiment is powdery. The magnetic resin composition may be a first magnetic resin composition or a second magnetic resin composition. When the magnetic resin composition is the first magnetic resin composition, the magnetic resin powder may be a powder of the first magnetic resin composition, or a semi-hardened powder of the first magnetic resin composition. The semi-hardened material is a material in which the resin composition is hardened to a state where it can be further hardened. That is, the semi-hardened material refers to a B stage state, which is an intermediate stage state of the hardening reaction. The intermediate stage refers to the stage between the varnish state (A stage state) and the fully hardened state (C stage state). For example, if the thermosetting resin composition is heated, the viscosity will gradually decrease, and then the curing will begin, and the viscosity will gradually increase. At this time, the semi-hardened state refers to a state from when the viscosity starts to rise until it is completely hardened. The average particle diameter of the particles constituting the magnetic resin powder is not particularly limited.

Examples of a method for preparing the magnetic resin powder include a method using a magnetic resin slurry described later and an atomization method; a three-roll mill, and the like; and a composite magnetic powder and a member selected from the group consisting of a hardening resin and a thermoplastic resin. A method of mixing at least one of the resin powders; and a method of pulverizing a magnetic resin sheet described later. From the standpoint that the particles constituting the magnetic resin powder can be made substantially spherical, the atomization method is particularly preferred. If the particles constituting the magnetic resin powder are approximately spherical, the fluidity during the subsequent molding process is good. In terms of the atomization method, the magnetic resin slurry is sprayed into mist-like particles under a high temperature (eg, 140 ° C.) environment and rapidly dried to volatilize the solvent, thereby preparing a magnetic resin powder. The first magnetic resin composition may increase the viscosity because the content of the composite magnetic powder is too large. However, if a magnetic resin slurry is temporarily prepared by using a solvent as described above and exposed to a high-temperature environment while spraying it, the solvent that is a volatile component will be rapidly released to become a powder, so the following place is rational.
[Magnetic resin paste]

The magnetic resin composition of the magnetic resin slurry (hereinafter referred to as a magnetic resin slurry) of this embodiment further contains a solvent and is in a slurry state. The slurry state means that the magnetic resin composition contains a solvent and is fluid at room temperature. The magnetic resin composition may be a first magnetic resin composition or a second magnetic resin composition. That is, the magnetic resin slurry may be in the form of a slurry containing a solvent in the first magnetic resin composition, or it may be in the form of a slurry containing a solvent in the second magnetic resin composition.

Examples of the solvent include methyl ethyl ketone (MEK), N, N-dimethylformamide (DMF), acetone, and methyl isobutyl ketone (MIBK). The solvent may be used singly or in combination of two or more kinds. When two or more solvents are mixed, the mixing ratio (mass ratio and volume ratio) is not particularly limited. The solvent content in the magnetic resin slurry is not particularly limited.

The filling rate of magnetic powder in the magnetic resin slurry (hereinafter referred to as the magnetic powder content) should preferably be 20% by volume or more and 99% by volume or less, and more preferably 53% by volume or more by 95% by volume relative to the solid content of the magnetic resin slurry. . If the content of the magnetic powder is within the above range, it is possible to easily control the fluidity of the magnetic resin sheet while increasing the real number portion (µ ') at 100 MHz. The calculation method of the magnetic powder content is calculated from the blending amount of each material constituting the solid content of the magnetic resin slurry and the specific gravity of each material. Here, the solid content of the magnetic resin slurry refers to the amount of the solvent deducted from the magnetic resin slurry.

The magnetic resin slurry may be prepared by, for example, dissolving at least one resin selected from the group consisting of a curable resin and a thermoplastic resin in a solvent to obtain a resin solution, and adding a composite magnetic powder to the obtained resin solution. A method of kneading, and finally adding a hardener, a hardening accelerator, a surface treatment agent, an elastomer, and the like and stirring until necessary, etc., if necessary.
[Magnetic resin sheet]

The magnetic resin composition of the magnetic resin sheet 1 (hereinafter referred to as the magnetic resin sheet 1) of this embodiment has a sheet shape. The magnetic resin composition may be a first magnetic resin composition or a second magnetic resin composition. When the magnetic resin composition is the first magnetic resin composition, the magnetic resin sheet 1 may be in the form of a sheet of the first magnetic resin composition or in the form of a semi-hardened material of the first magnetic resin composition.

The size of the magnetic resin sheet 1 may be appropriately adjusted depending on the use purpose of the magnetic resin sheet 1. The thickness of the magnetic resin sheet 1 is preferably 10 μm or more and 500 μm or less, and more preferably 50 μm or more and 300 μm or less. The Gleaning value showing the fluidity of the magnetic resin sheet 1 is preferably 60% or more and 95% or less, and more preferably 70% or more and less than 90%. If the Gleaning value of the magnetic resin sheet 1 is within the above range, for example, a laminated board with the magnetic resin sheet 1 laminated on the main surface of a wiring substrate having wiring formed on its main surface is formed by laminating or pressing. At this time, the magnetic resin sheet 1 with moderate fluidity can fully embed the wiring, and at the same time can avoid problems such as excessive lamination of the magnetic resin sheet 1 and contamination of the laminator or press due to the overflow of the magnetic resin sheet 1. The Gliness value can be measured in the same manner as the method described in the examples.

The volatile content of the magnetic resin sheet 1 is preferably 1% by mass or less, and more preferably 0.2% by mass or less. If the volatile content of the magnetic resin sheet 1 is within the above-mentioned range, the magnetic resin sheet 1 and the magnetic resin sheet 1 can be prevented from being stored in a frozen or cold storage state and returned to normal temperature when the operation surface is repeatedly covered with a cover film. A speckle pattern due to the volatilization of the solvent in the magnetic resin sheet 1 occurs between the cover films, and an excessive increase in the fluidity of the magnetic resin sheet 1 is prevented. The amount of volatilization can be measured in the same manner as in the examples.

The magnetic resin sheet 1 can be formed into a large-area magnetic material having a uniform thickness due to its sheet-like shape, and is particularly useful as a material for printed wiring boards which is difficult to cope with powdery and pasty forms. Since the magnetic resin sheet 1 is a semi-hardened material, it can be used, for example, for embedding and forming a circuit of a printed wiring board while applying pressure while heating and pressing.

The manufacturing method of the magnetic resin sheet 1 may include, for example, a method of coating a magnetic resin slurry on the film 2 to form a magnetic resin slurry layer 3 as shown in FIGS. 2A to 2C, and then drying or heating. The film 2 may be, for example, a polyethylene terephthalate (PET) film, a metal foil, or the like. The thickness of the film 2 is not particularly limited. The surface of the film 2 to which the magnetic resin paste layer 3 is to be applied should preferably be subjected to a mold release treatment in advance. In addition, a magnetic resin paste may be applied on the film 2 and dried or heated to produce a magnetic resin sheet 1.
[Magnetic resin sheet with metal foil]

The metal foil-attached magnetic resin sheet 30 (hereinafter referred to as the metal foil-attached magnetic resin sheet 30) of this embodiment is provided with a magnetic resin sheet 1 and laminated on at least one side of the magnetic resin sheet 1 as shown in FIG. 4. The metal foil 8 on the surface and having a thickness of 5 μm or less. In FIG. 4, the metal foil-attached magnetic resin sheet 30 has a two-layer structure composed of a magnetic resin sheet 1 and a metal foil 8 laminated on one surface of the magnetic resin sheet 1. The metal foil-attached magnetic resin sheet 30 may have a three-layer structure composed of a magnetic resin sheet 1 and two metal foils 8 laminated on both surfaces of the magnetic resin sheet 1. The metal foil-attached magnetic resin sheet 30 may include another layer between the magnetic resin sheet 1 and the metal foil 8.

As described above, the magnetic resin sheet 1 may have a sheet shape of the first magnetic resin composition, a sheet shape of a semi-hardened material of the first magnetic resin composition, or a sheet shape of the second magnetic resin composition.

The thickness of the metal foil-attached magnetic resin sheet 30 is preferably 10 μm or more and 800 μm or less. Examples of the material of the metal foil include copper, silver, aluminum, nickel, and stainless steel. The thickness of the metal foil is preferably 0.5 μm or more and 300 μm or less.

The method of adjusting the metal foil-attached magnetic resin sheet 30 may be, for example, a method of forming a metal foil 8 on one or both sides of the magnetic resin sheet 1 by a physical vapor deposition method. Examples of the physical vapor deposition method include a vacuum vapor deposition method, an ion plating method, and a sputtering method. In addition, a metal foil-coated magnetic resin sheet 30 can also be produced by applying a magnetic resin slurry or a magnetic resin paste to the metal foil 8 using a bar coater and drying or heating.
[Magnetic prepreg]

As shown in FIG. 5, the magnetic prepreg 40 (hereinafter referred to as the magnetic prepreg 40) of this embodiment is a fibrous substrate 42 and a magnetic resin composition 41 or a semi-hardened product of the magnetic resin composition 41. The magnetic prepreg 40 may be, for example, a magnetic resin composition 41 or a semi-hardened material of the magnetic resin composition 41 in which a fibrous substrate 42 is present. That is, the magnetic prepreg 40 includes a magnetic resin composition 41 or a semi-hardened material of the magnetic resin composition 41, and a fibrous base material present in the magnetic resin composition 41 or the semi-hardened material of the magnetic resin composition 41. 42. Since the magnetic prepreg 40 includes the fibrous base material 42, the magnetic prepreg 40 is superior to the magnetic resin sheet 1 in terms of lower bending strength and the like.

The magnetic resin composition may be a first magnetic resin composition or a second magnetic resin composition. That is, the magnetic prepreg 40 may include an object before the first resin composition is cured and the fibrous substrate 42, or may include a semi-hardened object and the fibrous substrate 42 of the first resin composition. The magnetic prepreg 40 may include a second resin composition and a fibrous substrate 42.

The thickness of the magnetic prepreg is preferably from 10 μm to 500 μm. Examples of the fibrous substrate 42 include cloth, non-woven fabric, pulp paper, and lint paper. As the woven fabric, for example, organic fiber cloth such as glass cloth, polyamide cloth, polyester cloth, and graphite cloth can be used. Examples of the nonwoven fabric include organic nonwoven fabrics such as glass nonwoven fabrics, polyamide nonwoven fabrics, and polyester nonwoven fabrics, graphite nonwoven fabrics, and nonwoven fabrics made of inorganic materials such as magnesium oxide. When a glass cloth is used, a magnetic prepreg 40 having excellent mechanical strength can be obtained. It is particularly preferable to use the glass cloth processed by the flat treatment as the fibrous substrate 42. The flattening process can be specifically exemplified by a method in which the glass cloth is continuously pressed by a pressure roller under an appropriate pressure to compress the yarn into a flat shape. The thickness of the fibrous base material 42 is not particularly limited, and for example, a material of 0.02 mm or more and 0.3 mm or less can be used.

When the magnetic prepreg 40 is manufactured, in order to impregnate the fibrous substrate 42 used as a base material for forming the magnetic prepreg 40, the magnetic resin composition 41 can be adjusted to be used in a varnish form. That is, a resin varnish in which the magnetic resin composition 41 is prepared into a varnish shape can be used. Such a resin varnish can be prepared as follows, for example.

First, each component of the magnetic resin composition 41 which is at least one resin selected from the group consisting of a curable resin and a thermoplastic resin and is soluble in a solvent is put into a solvent and dissolved. At this time, heating may be performed as necessary. After that, components containing the composite magnetic powder and insoluble in the solvent are added, and they are dispersed in a predetermined dispersion state by using a ball mill, a bead mill, a planetary mixer, and a roll mill, etc., thereby preparing a varnished state.组合 物。 Composition. Here, as the solvent to be used, the same solvent as the solvent that can be contained in the magnetic resin composition can be used.

When manufacturing the magnetic prepreg 40, the resin varnish whose magnetic resin composition 41 has been prepared into a varnish, the magnetic resin paste of the paste-like magnetic resin composition 41 described above, and the paste-like magnetic resin composition can be used. 41 of magnetic resin paste.

The manufacturing method of the magnetic prepreg 40 may be, for example, impregnating the magnetic resin composition 41 prepared with a varnish, magnetic resin paste containing the magnetic resin composition 41, or magnetic resin paste containing the magnetic resin composition 41 Method for drying the fibrous substrate 42 and the like.

The magnetic resin composition 41 can be impregnated into the fibrous base material 42 by dipping, coating, or the like. If necessary, it can be repeatedly immersed and coated for repeated impregnation. In addition, a variety of magnetic resin compositions 41 or magnetic resin pastes or magnetic resin pastes containing magnetic resin composition 41 having different compositions and concentrations can also be used for impregnation, and finally adjusted to the desired composition and impregnation. Penetration.

When the first magnetic resin composition containing a thermosetting resin is used for the magnetic resin composition 41, the first magnetic resin composition can be impregnated into the fibrous substrate 42 and then heated under desired conditions, for example, 80 ° C or higher It is 180 ° C or lower, and is heated for 1 minute or more and 10 minutes or less. The magnetic prepreg 40 including the semi-hardened product of the first magnetic resin composition can be produced by heating.
[Inductive parts]

The inductive component (hereinafter referred to as an inductive component) of this embodiment includes an insulating layer of a coil-shaped wiring and a covered coil-shaped wiring, and the insulating layer is a cured product of the first magnetic resin composition or a cured product of the second magnetic resin composition ( Hereinafter, it may be referred to as a magnetic material) molding. In this embodiment, since the hardened product of the first magnetic resin composition or the cured product of the second magnetic resin composition is used for molding, the Q value of the magnetic material of the insulating layer at 100 MHz is easily improved, and it can be suitably used as a high Frequency inductance parts. In particular, when the Q value of the hardened product of the first magnetic resin composition and the cured product of the second magnetic resin composition is 100 or more at 100 MHz, the Q value of the magnetic material of the insulating layer at 100 MHz will reach 20 or more. The inductive component of the embodiment is particularly suitable for use as a high-frequency inductive component. Examples of high-frequency inductive components include coils, inductors, filters, reactors, and transformers. The use of such inductive parts can include, for example, parts of noise filters, parts of impedance matching circuits, and the like. Examples of noise filters are low-pass filters and common-mode choke coils.

The structure of the inductive part can be adjusted appropriately depending on the use of the inductive part, and examples thereof include a coil type, a laminated type, and a thin film type.

The size of the inductance part can be adjusted appropriately depending on the use of the inductance part. When used as a high-frequency inductance part with a slightly cubic shape, it should be less than 15mm in length × 15mm in width × 10mm in height.

The shape of the coil-shaped wiring may be appropriately selected depending on the use purpose of the inductance part. For example, it may be formed in a planar swirl shape or a three-dimensional swirl shape. When a three-dimensional vortex is formed, the scroll structure may be a horizontal scroll structure or a longitudinal scroll structure. The coil-shaped wiring is electrically connected to other external electrode terminals for use at the beginning and end. Examples of the material of the coil-shaped wiring include Ag, Au, Cu, Ag-Pd, and Ni.

The insulating layer is covered with the coil-shaped wiring except for the start and end of the coil-shaped wiring. The raw material of the insulating layer is the first magnetic resin composition or the second magnetic resin composition.

The manufacturing method of the inductive component may be appropriately selected depending on the structure of the inductive component according to the use of the inductive component. For example, a method of forming a coil-shaped wiring by a three-dimensional connection such as a printing method or a sheet pile method. The printing method is a method in which a laminated sheet of a magnetic resin sheet or a second magnetic resin composition (hereinafter collectively referred to as a green sheet) and a conductor paste constituting a coil-shaped wiring are overlapped and printed on an inductor part. Method for forming three-dimensional coils inside. The sheet pile construction method is a method of forming a perforation on a green sheet, and then printing and filling a conductive paste for lamination.
Examples

The present invention is specifically described below through examples, but the present invention is not limited by the examples.

The raw materials of the magnetic resin slurry are shown below.
[Magnetic powder]
(First powder)
・ Alloy iron powder 1 ("AW2-08 / PF5KG" manufactured by EPSON ATMIX Corporation, representative composition: Fe-Si-Cr, average particle size: 4 μm, particle shape: all spherical, insulation treatment: available)
・ Alloy iron powder 2 ("AW2-08 / PF3KG" manufactured by EPSON ATMIX Corporation, representative composition: Fe-Si-Cr, average particle size: 3 μm, particle shape: spherical, insulation treatment: available)
(Other magnetic powder)
・ Alloy powder ("AW2-08 / PF8KG" manufactured by EPSON ATMIX Corporation, representative composition: Fe-Si-Cr, average particle size: 5 μm, particle shape: all spherical, insulation treatment: available)
・ Pure iron powder ("CIP FM" manufactured by BASF Japan Ltd., representative composition: Fe, average particle size: 2 μm, particle shape: all spherical, insulation treatment: none)
・ Ferrite magnet powder 1 ("E001" manufactured by Powdertech Co., Ltd., composition: Mn-Mg-Sr series ferrite magnet, average particle diameter: 50nm, particle shape: all spherical, insulation treatment: none)
・ Ferrite magnet powder 2 ("M001" manufactured by Powdertech Co., Ltd., composition: Mn-based ferrite magnet, average particle diameter: 50 nm, particle shape: all spherical, insulation treatment: none)
[Non-magnetic powder]
(Second powder)
・ Silicon oxide powder 1 ("SSP-10M" manufactured by Tokuyama Corporation, average particle diameter: 1 μm, particle shape: all spherical)
・ Alumina powder ("AO502" manufactured by Admatechs Company Limited, average particle diameter: 0.7 μm, particle shape: all spherical)
・ Silicon oxide powder 2 ("SSP-01M" manufactured by Tokuyama Corporation, average particle diameter: 0.1 μm, particle shape: all spherical)
[Thermosetting resin]
・ Bisphenol A epoxy resin ("850S" manufactured by DIC Corporation)
・ Bisphenol F-type epoxy resin ("YDF8170" manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd.)
・ Trifunctional epoxy resin ("VG3101" by Printec Corporation)
・ Polyfunctional epoxy resin ("NC3000" manufactured by Nippon Kayaku Co., Ltd.)
[Thermoplastic resin]
・ Phenoxy resin ("YP50EK35" manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd.)
[additive]
(hardener)
・ Dicyandiamide (`` Dicyandiamide '' manufactured by NIPPON CARBIDE INDUSTRIES CO., INC.)
(Hardening accelerator)
・ Imidazole 1 ("2E4MZ" manufactured by Shikoku Chemical Industry Co., Ltd.)
・ Imidazole 2 ("2MAOK-PW" manufactured by Shikoku Chemical Industry Co., Ltd.)
(Surface treatment agent)
・ Silane coupling agent 1 (`` A1871 '' by Momentive Performance Materials Japan Limited Liability Co.)
・ Silane coupling agent 2 (`` A186 '' by Momentive Performance Materials Japan Limited Liability Co.)
・ Dispersant (BYK-W903 by BYK Japan KK)
(Solvent)
・ MEK (methyl ethyl ketone)

・ DMF (N, N-dimethylformamide).

The measurement methods of the Glynis value, volatility, 2.0 rpm viscosity, shake index, DMA-Tg, surface resistance value, and magnetic characteristics are shown below.
[Determination of Gliness value]

The Gliness value is obtained in the following manner.

1) The following is prepared as a test plate 4: a magnetic sheet having a thickness of 200 μm is punched with a mold of 60 mmφ, and the polyethylene terephthalate film is peeled.

2) As shown in FIG. 3, a release PET film 5 having a thickness of 75 μm and a SUS plate 6 having a thickness of 1.8 mm were sequentially laminated on both sides of the test plate 4 to obtain a sample group.

3) Under atmospheric pressure, press the hot plate 7 whose hot plate temperature has been set to 135 ° C, and press the sample group at a real pressure of 2.0 MPa from above and below for 10 minutes to form.

4) Calculate the area of the test plate after forming by image processing.

5) Calculate the measured value twice by the following formula, and make the average value be the Glynis value. In addition, the area of the test piece of 6 cmφ before molding was 28.26 cm ² (30 m × 30 mm × 3.14).
Gliness value (%) = {1-28.26 / area of test piece after molding} × 100
Gliness value above 60: required for molding.
Gliness value above 70 and less than 90: suitable for embedded wiring.
Gliness value above 90: Excessive overflow during molding is not ideal.
[Determination of Volatility]

A magnetic sheet having a thickness of 200 μm was punched with a mold of 80 mmφ, and was allowed to stand in a dryer for 30 minutes to measure the initial weight. After that, it was put into a furnace at 163 ° C for 15 minutes, and after taking out, it was left to stand in a dryer for 30 minutes or more and cooled. The weight was measured immediately after taking out from the dryer, and the amount of volatilization was calculated by the following formula.
Volatility (%) = {sheet weight reduction / sheet initial weight} × 100
[2.0rpm viscosity]

The viscosity of the magnetic resin paste was measured using a rheometer "AR2000ex" manufactured by TA Instruments Japan Inc. Specifically, the gap between the upper and lower parallel plates having a diameter of 25 mm was set to 300 μm, and after the magnetic resin paste was filled therein, the viscosity was measured at a revolution of 0.2 rpm after a temperature equalization time of 2 minutes at room temperature. In addition, the viscosity measurement at a rotation speed of 2.0 rpm was also performed.
[Shake Index]

The shake index of the magnetic resin paste is calculated by the following formula using the 0.2 rpm viscosity and the 2.0 rpm viscosity value measured in the above [2.0 rpm viscosity] measurement.
Shake index = 0.2rpm viscosity / 2.0rpm viscosity
[Determination of DMA-Tg]

The DMA-Tg of the magnetic resin sheet was measured using a viscoelastic spectrometer "DMS100" manufactured by Seiko Instruments Inc. Specifically, the dynamic viscoelasticity measurement (DMA) was performed at a frequency of 10 Hz in the tensile module, and the temperature was raised from room temperature to 320 ° C at a temperature increase rate of 5 ° C / min, so that at this time tanδ showed a maximum temperature of DMA-Tg.
[Measurement of surface resistance]

The surface resistance value was measured in accordance with standard ASTM D257 using "R8340A" manufactured by ADVANTEST. Specifically, a test piece (50 mm × 50 mm × 1 mmt) was placed on a front electrode and a back electrode (50 mmφ) composed of a main electrode (25 mmφ) and an electrode (inner diameter 38 mmφ, outer diameter 50 mmφ) concentric with the main electrode. ), Measure under the following set conditions.
Setting conditions: applied voltage 100V, charging time 60 seconds, discharging time 0.1 seconds
[Determination of complex permeability]

Ten magnetic resin sheets were stacked, heated and pressed to harden and cut into a ring shape to obtain an annular core for evaluation (thickness: 1.0 mmt, outer diameter: 7.0 mm, inner diameter: 3.2 mm) (hereinafter referred to as magnetic material) ). The heating and pressing conditions were 180 ° C., 4.5 MPa (50 kgf / cm ² ), and 1 hour. The obtained complex magnetic permeability of the magnetic material at 100 MHz was measured using a "4291A RF impedance / material analyzer" manufactured by Hewlett-Packard Company. The measurement condition is that the current frequency is in a range of 1 MHz to 1.8 GHz and normal temperature. Obtain real part (μ ') and imaginary part (μ ") from the measured initial magnetization curve, and calculate the loss coefficient (Tanδ) and magnetic material Q from the obtained real part (μ') and imaginary part (μ") value. In the design of high-frequency inductance parts, the real part (μ ') should be 6.0 or more. In order to function as a high-frequency inductive component, the Q value of the magnetic material must be 20 or more. Furthermore, if you want to exert good performance as a high-frequency inductance part, the Q value of the magnetic material should be 33 or more.
[Examples 1 to 6]

In Examples 1 to 6, the magnetic powder content was changed, and the magnetic powder content showing a proper number part (μ ') when the function as a high-frequency inductance part was examined, that is, the real number part (μ') at 100 MHz showed a magnetic property of 6.0 or more. Powder content.

According to the blending ratio shown in Table 1, bisphenol A epoxy resin, trifunctional epoxy resin, multifunctional epoxy resin, phenoxy resin, MEK, and DMF were mixed to obtain a resin solution. Add alloy iron 2 (average particle size: 3 μm) and alumina (average particle size: 0.7 μm) to the obtained resin solution at the blending ratio shown in Table 1 and knead them. Add dicyandiamide, imidazole 1, and silane coupling agent 1 And a dispersant and stir well to obtain a magnetic resin slurry.

The obtained magnetic resin slurry was coated on the surface of the polyethylene terephthalate film that had been subjected to the release treatment and dried, thereby obtaining a magnetic resin sheet having a thickness of 200 μm in a B-stage state. The obtained magnetic resin sheet was used to measure the Glynis value, the volatilization amount, the DMA-Tg, the surface resistance value, and the magnetic characteristics. The results are shown in Table 1.

[Table 1]

It is clear from Table 1 that as the magnetic powder content increases, the real number part (μ ') and the imaginary number part (μ ") increase, and on the other hand, the Q value and the Gliness value of the magnetic material tend to decrease. Implementation In Examples 1 to 6, the best balance between the real number part (μ ') and the Glynis value was Example 4 with a magnetic powder content of 53.0% by volume.
[Examples 7, 8 and Comparative Examples 1 to 4]

In Examples 7, 8, and Comparative Examples 1 and 2, while maintaining the magnetic powder content (53.0% by volume) of Example 4, the first powder particle size ratio (hereinafter referred to as the particle size ratio) relative to the second powder was changed. ), The review will satisfy the particle size ratio of the Q value of the magnetic material necessary for functioning as a high-frequency inductance part, that is, the particle size ratio of the Q value of the magnetic material at 100 MHz or more. Comparative Example 3 and Comparative Example 4 did not contain the first powder. Specifically, a magnetic resin slurry was obtained in the same manner as in [Examples 1 to 6] except that the raw materials were blended in the blending ratio shown in Table 2. The obtained magnetic resin sheet was used to measure the Glynis value, the volatilization amount, the DMA-Tg, the surface resistance value, and the magnetic characteristics. The results are shown in Table 2.

[Table 2]

It is clear from Table 2 that the real number part (μ ′) and the Glynnian value tend to decrease as the particle size ratio increases. The imaginary part (μ ") decreases if the particle size ratio increases, and if the particle size ratio exceeds 4.3 (Example 4), it tends to be constant. The Q value of the magnetic material increases when the particle size ratio increases, and the particle size increases. If the diameter ratio exceeds 4.3 (Example 4), it tends to decrease. In addition, Comparative Example 3 does not contain alloy iron powder, so the Q value of the magnetic material is less than 20. Comparative Example 4 because the average particle diameter of the alloy iron powder is not less than 5 μm Therefore, the Q value of the magnetic material is less than 20. Among Examples 4, 7, 8, and Comparative Examples 1 to 4, the Q value of the magnetic material is the highest and the Gleasian value is good. The only Example 4 has a particle size ratio of 4.3. .
[Examples 9 to 13, Comparative Example 5]

In Examples 9 to 13, while maintaining the magnetic powder content (53.0% by volume) and the particle size ratio (4.3) of Example 4, the magnetic powder mass ratio (hereinafter referred to as mass ratio) with respect to the non-magnetic powder was changed, and the review was satisfied. The first mass ratio of the Q value of a magnetic material that exhibits good performance as a high-frequency inductive component, that is, a mass ratio of a magnetic material Q value of 33 or more at 100 MHz. Comparative Example 5 does not contain non-magnetic powder. Specifically, a magnetic resin slurry was prepared in the same manner as in [Examples 1 to 6] except that the raw materials were blended at the blending ratios shown in Table 3. The obtained magnetic resin sheet was used to measure the Glynis value, the volatilization amount, the DMA-Tg, the surface resistance value, and the magnetic characteristics. The results are shown in Table 3.

[table 3]

It is clear from Table 3 that as the mass ratio decreases, the Gliness value tends to decrease and the Q value of the magnetic material increases. On the other hand, since Comparative Example 5 does not contain non-magnetic powder, the Q value of the magnetic material is less than 20. In Examples 4, 9 to 13, and Comparative Example 5, those with a Q value of 33 or more for the magnetic material are Examples 11 to 13 with a mass ratio in the range of 4.0 to 5.7. In Examples 11 to 13, the best balance between the Q value of the magnetic material and the Gliness value is Example 12 with a mass ratio of 4.7.
[Examples 14 and 15]

In Examples 14 and 15, while maintaining the particle size ratio of 4.3 and the mass ratio of 6.0, ferrite magnet powders used as other magnetic powders were added, and changes in the Q value of the magnetic materials caused by the addition of the ferrite magnet powders were investigated. Specifically, a magnetic resin slurry was prepared in the same manner as in [Examples 1 to 6] except that the raw materials were blended in the blending ratio shown in Table 4. The obtained magnetic resin sheet was used to measure the Glynis value, the volatility, the DMA-Tg, the surface resistance value, and the magnetic characteristics. The results are shown in Table 4.

[Table 4]

As apparent from Table 4, in Examples 14 and 15 where the mixing ratio of the ferrite magnet powder to the first powder as a whole was about 6% by mass, although the Q value of the magnetic material was lower than that of Example 11, it was 20 the above. From these results, it is known that the Q value of the magnetic material containing ferrite magnet powder is lower than that of the magnetic material containing no ferrite magnet powder. Furthermore, even if the magnetic resin slurry contains a small amount of particulate ferrite magnet powder, the mixing ratio still satisfies the Q value of the magnetic material required to function as a high-frequency inductance part.
[Example 16]

Example 16 was made solvent-free to obtain a magnetic resin paste. Specifically, the raw materials shown in Table 5 were mixed at the blending ratio shown in Table 5 and kneaded until uniform to obtain a magnetic resin paste. As the mixing and kneading of the raw materials, a conventionally known mixer and kneader are used.


[table 5]

It is clear from Table 5 that the shake index of Example 16 prepared without the solvent is 3.8 and the Q value is 20 or more. From this result, it was found that even if the magnetic resin composition does not contain a solvent, the paste-like magnetic resin paste still has excellent fluidity and can satisfy the Q value of the magnetic material required to function as a high-frequency inductance part.

It is clear from the above embodiment that the composite magnetic powder according to the first aspect of the present invention includes a magnetic powder including a first powder and a nonmagnetic powder including a second powder. The first powder is composed of an alloy iron powder, and the second powder is composed of at least one of an alumina powder and a silicon oxide powder. The average particle diameter of the first powder is less than 5 μm and is 3 times to 30 times the average particle diameter of the second powder.

According to the first aspect, the Q value of the magnetic material in the high frequency band can be increased.

The composite magnetic powder of the second aspect of the present invention: in the first aspect, the mixing ratio of the magnetic powder is 4 parts by mass or more and 19 parts by mass or less with respect to 1 part by mass of the non-magnetic powder.

According to the second aspect, the Q value of the magnetic material at 100 MHz can be balanced with the fluidity of the magnetic material before processing.

The composite magnetic powder according to the third aspect of the present invention: the magnetic powder in the first or second aspect is subjected to insulation treatment.

According to the third aspect, the Q value of the magnetic material can be further increased.

A magnetic resin composition according to a fourth aspect of the present invention includes the composite magnetic powder according to any one of the first to third aspects and at least one resin selected from the group consisting of a curable resin and a thermoplastic resin.

According to the fourth aspect, a magnetic material having a high Q value in a high frequency band can be obtained.

The magnetic resin composition of the fifth aspect of the present invention: the content of the composite magnetic powder in the fourth aspect is 70% by mass or more and 99.5% by mass or less of the solid content of the magnetic resin composition as a whole.

According to the fifth aspect, a magnetic material suitable for high-frequency inductor applications can be obtained.

The magnetic resin composition of the sixth aspect of the present invention: in the fourth or fifth aspect, the hardened or cured product of the magnetic resin composition has a Q value of 20 or more at a frequency of 100 MHz.

According to the sixth aspect, a magnetic material suitable for high-frequency inductor applications can be obtained.

The magnetic resin paste of the seventh aspect of the present invention: the magnetic resin composition of any one of the fourth to sixth aspects is in a paste form.

According to the seventh aspect, a magnetic material with good fluidity can be obtained.

The magnetic resin powder according to an eighth aspect of the present invention: the magnetic resin composition according to any one of the fourth to sixth aspects is powdery.

According to the eighth aspect, a powdery magnetic material can be obtained.

The magnetic resin slurry of the ninth aspect of the present invention: The magnetic resin composition of any one of the fourth to sixth aspects further contains a solvent and is in the form of a slurry.

According to the ninth aspect, a magnetic material with good fluidity can be obtained.

A magnetic resin sheet according to a tenth aspect of the present invention: the magnetic resin composition according to any one of the fourth to sixth aspects is in a sheet shape.

According to the tenth aspect, a magnetic material having a uniform thickness can be obtained.

The magnetic resin sheet of the eleventh aspect of the present invention: in the tenth aspect, the thickness is 10 μm or more and 500 μm or less.

According to the eleventh aspect, a magnetic material having a certain thickness can be obtained.

A twelfth aspect of the present invention with a metal foil-attached magnetic resin sheet includes: the tenth or eleventh aspect of the magnetic resin sheet; and a layer laminated on at least one side of the magnetic resin sheet and having a thickness of 5 μm or less Metal foil.

According to the twelfth aspect, a magnetic material with a metal foil can be obtained.

A magnetic prepreg according to a thirteenth aspect of the present invention includes: a fibrous substrate; and a magnetic resin composition or a semi-hardened material of the magnetic resin composition according to any one of the fourth to sixth aspects.

According to the thirteenth aspect, a magnetic material having excellent bending strength can be obtained.

An inductance component of a fourteenth aspect of the present invention includes an insulating layer of a coiled wiring and a covered coiled wiring, and the insulating layer is formed of a hardened or cured product of the magnetic resin composition of any of the fourth to sixth aspects.

According to the fourteenth aspect, an inductive component suitable for use as a high-frequency inductive component can be produced.

1‧‧‧ magnetic resin sheet

2‧‧‧ film

3‧‧‧ Magnetic resin paste layer

4‧‧‧test plate

5‧‧‧ release PET film

6‧‧‧SUS board

7‧‧‧ hot plate

8‧‧‧ metal foil

10‧‧‧ Large diameter magnetic particles

11‧‧‧ Appearance of large particles in the form of most large diameter magnetic particles close to each other

20‧‧‧ Small diameter non-magnetic particles

21‧‧‧ Layer made of small diameter non-magnetic particles

30‧‧‧ with metal foil magnetic resin sheet

40‧‧‧ Magnetic prepreg

41‧‧‧magnetic resin composition

42‧‧‧ Fibrous substrate

FIG. 1: FIG. 1A is a schematic cross-sectional view for explaining the arrangement relationship between the magnetic particles constituting the first powder and the non-magnetic particles constituting the second powder in the composite magnetic powder of the present invention; FIG. 1B is a schematic cross-sectional view showing most Two large-diameter magnetic particles are close to each other to form a large particle in appearance; FIG. 1C is a schematic cross-sectional view for explaining magnetic particles and non-magnetic particles when the average particle diameter of the first powder is less than 3 times the average particle diameter of the second powder. FIG. 1D is a schematic cross-sectional view for explaining the arrangement relationship between magnetic particles and non-magnetic particles when the average particle diameter of the first powder is 30 times greater than the average particle diameter of the second powder.

2: FIG. 2A is a schematic cross-sectional view for explaining a part of a manufacturing method of a magnetic resin sheet according to an embodiment of the present invention; FIG. 2B is a schematic cross-sectional view for explaining a part of a manufacturing method of a magnetic resin sheet according to an embodiment of the present invention 2C is a schematic cross-sectional view for explaining a part of a method for manufacturing a magnetic resin sheet according to an embodiment of the present invention.

FIG. 3 is a schematic diagram for explaining a method of measuring a Glynis value.

4 is a schematic cross-sectional view of a metal foil-attached magnetic resin sheet according to an embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view of a magnetic prepreg according to an embodiment of the present invention.

Claims (14)

A composite magnetic powder containing: A magnetic powder containing a first powder and a non-magnetic powder containing a second powder, The first powder is composed of an alloy iron powder, and the second powder is composed of at least one of an alumina powder and a silicon oxide powder. The average particle diameter of the first powder is less than 5 μm and is 3 times to 30 times the average particle diameter of the second powder. The composite magnetic powder according to claim 1, wherein the mixing ratio of the magnetic powder is 4 parts by mass or more and 19 parts by mass or less with respect to 1 part by mass of the non-magnetic powder. The composite magnetic powder according to claim 1 or 2, wherein the aforementioned magnetic powder is treated with insulation. A magnetic resin composition containing: The composite magnetic powder of any one of claims 1 to 3; and At least one resin selected from the group consisting of a curable resin and a thermoplastic resin. The magnetic resin composition according to claim 4, wherein the content of the composite magnetic powder is 70% by mass or more and 99.5% by mass or less of the solid content of the magnetic resin composition as a whole. For example, the magnetic resin composition of claim 4, wherein the hardened or cured product of the magnetic resin composition has a Q value of 20 or more at a frequency of 100 MHz. A magnetic resin paste, which is a magnetic resin composition according to any one of claims 4 to 6 in a paste form. A magnetic resin powder is a magnetic resin composition according to any one of claims 4 to 6 in a powder form. A magnetic resin slurry, which is a magnetic resin composition according to any one of claims 4 to 6, which further contains a solvent and is in a slurry state. A magnetic resin sheet is a sheet-like magnetic resin composition according to any one of claims 4 to 6. The magnetic resin sheet according to claim 10, wherein the sheet thickness is 10 μm or more and 500 μm or less. A metal foil-attached magnetic resin sheet comprising: If requested, the magnetic resin sheet of item 10 or 11; and The metal foil is laminated on at least one side of the magnetic resin sheet and has a thickness of 5 μm or less. A magnetic prepreg with: Fibrous substrate; and The magnetic resin composition according to any one of claims 4 to 6, or the semi-hardened product of the magnetic resin composition. An inductive component having: Coiled wiring and the insulation layer covering the coiled wiring, The aforementioned insulating layer is formed of a hardened or cured product of the magnetic resin composition according to any one of claims 4 to 6.