WO2023149454A1 - Magnetic resin composition, magnetic sheet, and inductor component - Google Patents

Magnetic resin composition, magnetic sheet, and inductor component Download PDF

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Publication number
WO2023149454A1
WO2023149454A1 PCT/JP2023/003168 JP2023003168W WO2023149454A1 WO 2023149454 A1 WO2023149454 A1 WO 2023149454A1 JP 2023003168 W JP2023003168 W JP 2023003168W WO 2023149454 A1 WO2023149454 A1 WO 2023149454A1
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WIPO (PCT)
Prior art keywords
magnetic
resin composition
mass
magnetic resin
powder
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PCT/JP2023/003168
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French (fr)
Japanese (ja)
Inventor
諒 永塚
雄亮 大石
隆行 辻
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パナソニックＩｐマネジメント株式会社
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Publication of WO2023149454A1 publication Critical patent/WO2023149454A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/05—Metallic powder characterised by the size or surface area of the particles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/02—Compacting only
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H01F1/20—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder
    • H01F1/22—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together
    • H01F1/24—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together the particles being insulated
    • H01F1/26—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together the particles being insulated by macromolecular organic substances
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/33—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials mixtures of metallic and non-metallic particles; metallic particles having oxide skin
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/34—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials non-metallic substances, e.g. ferrites
    • H01F1/36—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials non-metallic substances, e.g. ferrites in the form of particles
    • H01F1/37—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials non-metallic substances, e.g. ferrites in the form of particles in a bonding agent

Definitions

  • the present disclosure generally relates to magnetic resin compositions, magnetic sheets, and inductor parts, and more specifically to magnetic resin compositions, magnetic sheets, and inductor parts containing magnetic powder.
  • Patent Document 1 discloses a resin composition.
  • This resin composition contains (A) a thermosetting resin, (B) a curing agent, (C) a thermoplastic resin, (D) a magnetic filler, and (E) an inorganic filler.
  • a thermosetting resin a thermosetting resin
  • B a curing agent
  • C a thermoplastic resin
  • D a magnetic filler
  • E an inorganic filler.
  • the magnetic loss at a frequency of 100 MHz of the cured product obtained by thermosetting the resin composition of Patent Document 1 is 0.05 or less.
  • An object of the present disclosure is to provide a magnetic resin composition, a magnetic sheet, and an inductor component that can reduce magnetic loss and improve DC superimposition characteristics.
  • a magnetic resin composition according to one aspect of the present disclosure contains magnetic powder, a thermosetting resin, and a curing agent.
  • the magnetic powder contains carbonyl iron powder having a 50% volume average particle size (D50) of 4.0 ⁇ m or less.
  • a magnetic sheet according to one aspect of the present disclosure includes the magnetic resin composition.
  • An inductor component includes a coil and a molded body that incorporates at least part of the coil.
  • the molded body is formed of a cured product of the magnetic resin composition.
  • the inductance of inductors used has been reduced, and the size and thickness have been reduced, low DC resistance, large current support, and high reliability. sex is required.
  • DC superimposition characteristics are one of the characteristics that affect the performance of power inductors (inductors for power supply circuits).
  • the DC superimposition characteristic is the property that the inductance decreases as the DC bias current flowing through the inductor increases.
  • the DC superimposition characteristics are evaluated using, for example, a DC superimposition allowable current value as an index. DC superimposition characteristics are better as the DC superimposition allowable current value is larger.
  • the allowable DC superposition current value is the current value when the rate of decrease from the initial value of the inductance reaches, for example, 20%.
  • the present inventors have continued intensive research not only to reduce the magnetic loss but also to improve the DC superimposition characteristics, and as a result, have developed the following magnetic resin composition.
  • the magnetic resin composition according to this embodiment contains magnetic powder, a thermosetting resin, and a curing agent.
  • the magnetic powder contains carbonyl iron powder with a 50% volume average particle size (D50) of 4.0 ⁇ m or less.
  • D50 volume average particle size
  • the inventors of the present invention also obtained the knowledge that it is difficult to improve the DC superimposition characteristics only with an iron-based amorphous alloy during the development.
  • the inclusion of the carbonyl iron powder in the magnetic powder can improve the DC bias characteristics. Further, the 50% volume average particle diameter (D50) of the carbonyl iron powder is 4.0 ⁇ m or less, so that the magnetic loss can be reduced.
  • relative permeability means the real part ( ⁇ r ′) of the complex relative permeability ( ⁇ r ) .
  • magnetic loss means a loss coefficient (tan ⁇ ).
  • the relational expression of the complex relative permeability ( ⁇ r ) is summarized below.
  • the magnetic resin composition according to the present embodiment contains magnetic powder, a thermosetting resin, and a curing agent.
  • the magnetic resin composition may further contain additives.
  • the magnetic resin composition may further contain a solvent.
  • Magnetic powder is a powdery substance that can be magnetized. In this way, the inclusion of the magnetic powder in the magnetic resin composition makes it possible to obtain a cured product having magnetic properties. Magnetic properties are the magnetic properties exhibited when magnetized. Specific examples of magnetic properties include relative magnetic permeability and magnetic flux density.
  • the magnetic powder content is preferably 78% by mass or more, more preferably 85% by mass or more, relative to the total solid content of 100% by mass of the magnetic resin composition.
  • the magnetic powder content is 78% by mass or more, a decrease in relative magnetic permeability can be suppressed. Desired magnetic properties can be easily obtained.
  • the magnetic powder content is 85% by mass or more, the decrease in relative magnetic permeability can be further suppressed. It becomes easier to obtain a high relative magnetic permeability.
  • the solid content of the magnetic resin composition means the magnetic resin composition excluding volatile substances such as solvents.
  • the magnetic powder content is preferably 96% by mass or less, more preferably 95% by mass or less, relative to the total solid content of 100% by mass of the magnetic resin composition.
  • the magnetic powder content is 96% by mass or less, moldability can be improved. Fluidity is easily obtained during molding.
  • moldability can be further improved. It becomes easier to fill a narrow gap or the like with the magnetic resin composition.
  • a cured product of the magnetic resin composition according to the present embodiment can have a high relative magnetic permeability at high frequencies.
  • the high frequency band is, for example, several MHz or more and several GHz or less, including 100 MHz.
  • the magnetic powder contains carbonyl iron powder.
  • the magnetic powder further contains ferrite powder.
  • Carbonyl Iron Powder is pure iron powder. Carbonyl iron powder is produced by pyrolysis of pentacarbonyl iron (Fe(CO) 5 ). Particle size distribution is controlled by pyrolysis conditions. The particle shape of the carbonyl iron powder is preferably spherical, more preferably spherical. Chemical components of the carbonyl iron powder include Fe, C, O, and the like. In the carbonyl iron powder, Fe accounts for 95% by mass or more.
  • the 50% volume average particle diameter (D50) of the carbonyl iron powder is preferably 0.01 ⁇ m or more, more preferably 0.5 ⁇ m or more.
  • the term "50% volume average particle size (D50)" means the particle size (D50) at an integrated value of 50% in a particle size distribution measured based on a particle size distribution analyzer based on a laser scattering/diffraction method.
  • the 50% volume average particle size (D50) of the carbonyl iron powder is 4.0 ⁇ m or less. If the 50% volume average particle size (D50) of the carbonyl iron powder exceeds 4.0 ⁇ m, magnetic loss may increase.
  • the 50% volume average particle size (D50) of the carbonyl iron powder is preferably 3.0 ⁇ m or less.
  • the magnetic powder contains the carbonyl iron powder, so that the DC superimposition characteristics can be improved. Further, the 50% volume average particle diameter (D50) of the carbonyl iron powder is 4.0 ⁇ m or less, so that the magnetic loss can be reduced.
  • the 90% volume average particle size (D90) of the carbonyl iron powder is preferably 1.0 ⁇ m or more, more preferably 3.0 ⁇ m or more.
  • the term "90% volume average particle size (D90)" means the particle size (D90) at an integrated value of 90% in a particle size distribution measured based on a particle size distribution analyzer based on a laser scattering/diffraction method.
  • the 90% volume average particle size (D90) of the carbonyl iron powder is preferably less than 9.0 ⁇ m, more preferably 7.0 ⁇ m or less. If the 90% volume average particle diameter (D90) of the carbonyl iron powder is 9.0 ⁇ m or more, magnetic loss may increase.
  • the 50% volume average particle size (D50) and 90% volume average particle size (D90) are measured using, for example, a particle size distribution analyzer (model: MT3300) manufactured by Microtrack Bell Co., Ltd. can do. Measurement conditions are, for example, a transmission mode for particle permeability, ethanol as a solvent, and a solvent refractive index of 1.36.
  • the carbonyl iron powder is preferably insulated. That is, the magnetic powder preferably contains an insulation-treated carbonyl iron powder.
  • the insulated carbonyl iron powder is obtained by treating the surface of the carbonyl iron powder with, for example, a phosphorus compound (phosphoric acid, etc.) or a metal oxide (silica, etc.). By insulating the carbonyl iron powder in this manner, eddy current loss between particles of the carbonyl iron powder is reduced.
  • the above insulation-treated carbonyl iron powder may be surface-treated with an organic surface treatment agent.
  • the organic surface treatment agent include, but are not particularly limited to, a coupling agent (described later), an organic acid, and the like.
  • the content of the carbonyl iron powder is preferably 70% by mass or more, more preferably 75% by mass or more, relative to the total solid content of 100% by mass of the magnetic resin composition.
  • the content of the carbonyl iron powder is 70% by mass or more, a decrease in relative magnetic permeability can be suppressed. Furthermore, deterioration of DC superimposition characteristics can be suppressed.
  • the content of the carbonyl iron powder is preferably 94% by mass or less, more preferably 93% by mass or less, relative to the total solid content of 100% by mass of the magnetic resin composition.
  • the content of the carbonyl iron powder is 94% by mass or less, moldability can be improved.
  • Ferrite powder is a ceramic powder containing iron oxide as a main component.
  • ferrite include, but are not particularly limited to, spinel ferrite, hexagonal ferrite, and garnet ferrite.
  • spinel ferrite include, but are not particularly limited to, magnetite (magnetite, Fe 3 O 4 ).
  • the particle shape of the ferrite powder is preferably spherical.
  • Ferrite powder has higher electrical insulation than carbonyl iron powder. Therefore, by including ferrite powder in the magnetic powder, the loss factor (tan ⁇ ) of the cured product of the magnetic resin composition can be further reduced.
  • the ferrite powder may be surface-treated, for example, using an inorganic material (silica, etc.) or a coupling agent (described later).
  • an inorganic material silicon, etc.
  • a coupling agent described later.
  • the 50% volume average particle size (D50) of the ferrite powder is preferably smaller than the 50% volume average particle size (D50) of the carbonyl iron powder.
  • the 50% volume average particle diameter (D50) of the ferrite powder is preferably 0.01 ⁇ m or more, more preferably 0.1 ⁇ m or more.
  • the 50% volume average particle diameter (D50) of the ferrite powder is preferably 1.0 ⁇ m or less.
  • the ferrite powder particles can fill the gaps formed between the carbonyl iron powder particles. This suppresses the contact between the particles of the carbonyl iron powder, facilitating the formation of a close-packed structure. Moreover, an increase in eddy current loss in the particles of the ferrite powder is suppressed, and the loss factor (tan ⁇ ) of the cured product of the magnetic resin composition is less likely to increase.
  • the ferrite powder content is preferably 5% by mass or more, more preferably 10% by mass or more, relative to the total solid content of 100% by mass of the magnetic resin composition.
  • the ferrite powder content is preferably 30% by mass or less, more preferably 20% by mass or less, relative to the total solid content of 100% by mass of the magnetic resin composition.
  • the content of the ferrite powder is 30% by mass or less, it is possible to suppress deterioration of the DC superimposition characteristics of the cured product of the magnetic resin composition.
  • thermosetting resins include, but are not limited to, epoxy resins, phenoxy resins, phenol resins, silicone resins, acrylic resins, urethane resins, polyimide resins, polyphenylene ether resins, benzoxazine resins, bismaleimide resins, fluorine resins, and organic phosphoric acid compounds.
  • the thermosetting resin preferably contains at least one of epoxy resin and phenoxy resin. This can improve the fluidity of the magnetic resin composition during molding. Especially when the thermosetting resin contains an epoxy resin, the adhesiveness and dimensional stability of the cured product of the magnetic resin composition can be improved. It is also possible to increase the degree of freedom in designing the formulation of the magnetic resin composition.
  • the content of the epoxy resin is preferably 3% by mass or more with respect to the total solid content of 100% by mass of the magnetic resin composition.
  • the content of the epoxy resin is preferably 15% by mass or less with respect to the total solid content of 100% by mass of the magnetic resin composition.
  • the thermosetting resin contains a phenoxy resin, it is possible to improve the bending properties (such as flexibility) of the cured product of the magnetic resin composition.
  • the content of the phenoxy resin is preferably 2% by mass or less with respect to the total solid content of 100% by mass of the magnetic resin composition.
  • Epoxy resin is a compound having at least one epoxy group in one molecule.
  • examples of epoxy resins include, but are not limited to, alkylphenol novolac type epoxy resins such as phenol novolak type epoxy resins and cresol novolak type epoxy resins; naphthol novolak type epoxy resins; phenol aralkyl type epoxy resins having a phenylene skeleton, biphenylene skeleton, etc.
  • biphenyl aralkyl type epoxy resins such as biphenyl aralkyl type epoxy resins; naphthol aralkyl type epoxy resins having a phenylene skeleton, biphenylene skeleton, etc.; polyfunctional epoxy resins such as triphenol methane type epoxy resins and alkyl-modified triphenol methane type epoxy resins; triphenylmethane type epoxy resins tetrakisphenol ethane type epoxy resin; dicyclopentadiene type epoxy resin; stilbene type epoxy resin; bisphenol type epoxy resin such as bisphenol A type epoxy resin and bisphenol F type epoxy resin; biphenyl type epoxy resin; naphthalene type epoxy resin; formula epoxy resins; bromine-containing epoxy resins such as bisphenol A-type bromine-containing epoxy resins; glycidylamine-type epoxy resins obtained by reacting polyamines such as diaminodiphenylmethane and isocyanuric acid with epichlorohydrin; and
  • the epoxy resin may be liquid or powdery.
  • a liquid epoxy resin makes it easier to liquefy the magnetic resin composition.
  • the viscosity and fluidity of the liquid magnetic resin composition can be adjusted.
  • a powdery epoxy resin is used, the magnetic resin composition can be easily pulverized.
  • the amount of the powdery epoxy resin used blocking during long-term storage of the powdery magnetic resin composition can be suppressed.
  • the magnetic resin composition can be easily made into a semi-solid or solid sheet.
  • a phenoxy resin is a linearly polymerized resin through a condensation reaction between bisphenol A and epichlorohydrin.
  • the phenoxy resin may have terminal epoxy groups and/or hydroxyl groups.
  • the weight average molecular weight (Mw) of the phenoxy resin is preferably 50,000 to 100,000, more preferably 60,000 to 80,000.
  • the magnetic resin composition may contain curable resins other than those mentioned above.
  • the magnetic resin composition may contain, for example, a photocurable resin.
  • the curing agent has a function of curing the curable component in the magnetic resin composition.
  • the curing agent cures the thermosetting resin in the magnetic resin composition.
  • Curing agents also include curing accelerators, curing catalysts, and curing aids.
  • the curing agent is not particularly limited, but for example, phenolic curing agents, acid anhydride curing agents, aliphatic amine curing agents, aromatic amine curing agents, imidazole curing accelerators, tertiary amines, and phosphorus compounds.
  • the content of the curing agent is preferably 0.01% by mass or more with respect to the total solid content of 100% by mass of the magnetic resin composition.
  • the content of the curing agent is preferably 3% by mass or less with respect to 100% by mass of the total solid content of the magnetic resin composition.
  • Additives can impart various functions to the magnetic resin composition.
  • additives include, but are not limited to, coupling agents, dispersants, low-elasticity imparting agents (elastomers), pigments (colorants), antioxidants, flame retardants, non-magnetic fillers, antifoaming agents, and leveling agents. agents and the like.
  • a coupling agent is used to form an interface between the magnetic powder and the thermosetting resin or the like.
  • a coupling agent improves the affinity between the magnetic powder and the thermosetting resin or the like.
  • the coupling agent is not particularly limited, but includes, for example, silane coupling agents, titanate coupling agents, aluminum coupling agents, aluminum/zirconium silane coupling agents, and the like.
  • silane coupling agent include, but are not limited to, epoxy group-containing silane coupling agents represented by ⁇ -glycidoxypropyltrimethoxysilane; ⁇ -aminopropyltrimethoxysilane, N- ⁇ (aminoethyl )- ⁇ -aminopropyltrimethoxysilane and other aminosilanes; N-phenyl- ⁇ -aminopropyltrimethoxysilane and other aminophenylsilanes; mercaptosilanes typified by 3-mercaptopropyltrimethoxysilane; ureidosilanes, alkylsilanes, vinyl silanes, isocyanurate silanes, acrylic silanes, and the like.
  • the content of the coupling agent is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, relative to 100 parts by mass of the magnetic powder.
  • the content of the coupling agent is preferably 5.0 parts by mass or less, more preferably 1.0 parts by mass or less, relative to 100 parts by mass of the magnetic powder.
  • the method of using the coupling agent is not particularly limited, but includes the direct treatment method and the integral blend method.
  • the direct treatment method is a method in which magnetic powder treated with a coupling agent is mixed with a thermosetting resin or the like.
  • the integral blend method is a method of adding a coupling agent to a mixture of a magnetic powder and a thermosetting resin or the like.
  • the wettability between the magnetic powder and the thermosetting resin can be improved, and the dispersibility of the magnetic powder can be improved.
  • Dispersants are mainly used to improve the dispersibility of magnetic powder.
  • Dispersants are not particularly limited, but examples include polyoxyethylene-laurylamine, phosphorus-based surfactants, long-chain fatty acids, long-chain fatty acid metal salts, ammonium polycarboxylate, sodium polycarboxylate, sodium naphthalenesulfonate, and the like. are mentioned.
  • Phosphorus-based surfactants are not particularly limited, but include, for example, phosphate esters and the like. The phosphate ester may have at least one of a long-chain alkyl group, a polyester group, and an alkyl ether group.
  • the dispersant may be acidic or basic.
  • the acidic dispersant include, but are not particularly limited to, surfactants having a sulfonic acid group, a carboxyl group, or the like.
  • the basic dispersant include, but are not particularly limited to, amine salts of phosphoric acid esters.
  • the content of the dispersant is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, relative to 100 parts by mass of the magnetic powder.
  • the content of the dispersant is preferably 5.0 parts by mass or less, more preferably 1.0 parts by mass or less, relative to 100 parts by mass of the magnetic powder.
  • the direct processing method and the integral blending method can be mentioned in the same way as the method of using the coupling agent.
  • the dispersant together with the coupling agent the effects of both can be enhanced.
  • the low-elasticity imparting agent reduces the elastic modulus of the cured product of the magnetic resin composition. This reduces stress in the cured product, imparts flexibility to the cured product, and toughens the cured product.
  • a low modulus imparting agent may be used as a substitute for the phenoxy resin.
  • the low-elasticity-imparting agent include, but are not limited to, thermoplastic elastomers, core-shell rubbers, and silicone rubbers.
  • thermoplastic elastomers include styrene-based, olefin-based, urethane-based, amide-based, ester-based, PVC-based, and fluorine-based elastomers.
  • a pigment is used for coloring the magnetic resin composition.
  • Pigments are roughly classified into inorganic pigments and organic pigments.
  • inorganic pigments include, but are not limited to, carbon black, titanium white (titanium dioxide), and iron oxide red (red iron oxide).
  • organic pigments include, but are not limited to, azo pigments and polycyclic pigments.
  • the antioxidant suppresses oxidation of the magnetic resin composition. When oxidation is suppressed, the heat resistance of the cured product of the magnetic resin composition can be improved. Antioxidants are roughly classified into radical scavengers and peroxide decomposers.
  • the radical scavenger is not particularly limited, but includes, for example, phenol-based antioxidants and aromatic amine-based antioxidants.
  • phenolic antioxidants are excellent in thermal antioxidant function and discoloration resistance.
  • Phenolic antioxidants are not particularly limited, but include, for example, hindered phenol antioxidants.
  • the peroxide decomposer is not particularly limited, but includes, for example, sulfur-based antioxidants and phosphorus-based antioxidants.
  • the flame retardant imparts flame retardancy to the magnetic resin composition and its cured product.
  • the flame retardant is not particularly limited, but examples thereof include halogen-based flame retardants (bromine-based flame retardants, etc.), phosphorus-based flame retardants, and the like.
  • the halogen-based flame retardant preferably contains at least one of ethylenedipentabromobenzene, ethylenebistetrabromoimide, decabromodiphenyloxide, and tetradecabromodiphenoxybenzene. Since the melting points of these materials are high (for example, 300° C. or higher), it is thought that detachment of halogen at high temperatures can be suppressed, and deterioration of the heat resistance of the cured product of the magnetic resin composition can be suppressed.
  • Phosphorus-based flame retardants are not particularly limited, but include, for example, phosphate-based flame retardants, phosphazene-based flame retardants, bisdiphenylphosphine oxide-based flame retardants, and phosphinate-based flame retardants.
  • phosphate ester-based flame retardant include, but are not limited to, condensed phosphate of dixylenyl phosphate.
  • phosphazene-based flame retardant include, but are not particularly limited to, phenoxyphosphazene.
  • the bisdiphenylphosphine oxide-based flame retardant is not particularly limited, but includes, for example, xylylenebisdiphenylphosphine oxide.
  • a non-magnetic filler is a filler that does not have magnetism.
  • the nonmagnetic filler can, for example, reduce the coefficient of linear expansion of the cured product of the magnetic resin composition, reduce the hygroscopicity, and impart flame retardancy to the cured product.
  • Examples of non-magnetic fillers include, but are not limited to, silica (silicon dioxide), alumina (aluminum oxide), talc, mica, clay, titania (titanium dioxide), aluminum hydroxide, and magnesium hydroxide.
  • Aluminum hydroxide and magnesium hydroxide can also function as flame retardants.
  • a solvent is used for diluting the magnetic resin composition. This makes it easier to mold the magnetic resin composition into a sheet.
  • solvents include, but are not limited to, ketone solvents, N,N-dimethylformamide, dimethylacetamide, and toluene.
  • ketone-based solvent examples include, but are not particularly limited to, methyl ethyl ketone, acetone, methyl isobutyl ketone, cyclohexanone, and the like.
  • the magnetic resin composition according to this embodiment is sheet-like, liquid-like, or powder-like.
  • the sheet-shaped magnetic resin composition is a magnetic sheet.
  • the magnetic sheet will be described later. Since the liquid magnetic resin composition has a low viscosity at the time of molding, it is excellent in filling narrow gaps and the like. On the other hand, since the powdery magnetic resin composition can be pressurized, it is possible to improve filling properties in narrow gaps and the like.
  • the magnetic resin composition according to this embodiment can have the following characteristics.
  • the cured product of the magnetic resin composition preferably has a relative magnetic permeability of 8 or more, more preferably 9 or more at a frequency of 100 MHz.
  • the upper limit of the relative magnetic permeability is not particularly limited, it is 100 or less, for example.
  • the loss factor (tan ⁇ ) at a frequency of 100 MHz of the cured product of the magnetic resin composition is preferably 0.04 or less, more preferably 0.03 or less. Thereby, heat loss can be reduced. A smaller loss factor (tan ⁇ ) is more preferable.
  • the lower limit of the loss factor (tan ⁇ ) is preferably 0.001 or more, more preferably 0.01 or more.
  • the DC superposition allowable current value of the cured product of the magnetic resin composition at a frequency of 100 kHz is preferably 15 A or more, more preferably 16 A or more. It is preferable that the DC superimposition allowable current value is as large as possible.
  • the upper limit of the DC superposition allowable current value is not particularly limited, but is, for example, 50 A or less.
  • the magnetic resin composition according to this embodiment has excellent magnetic properties at high frequencies. That is, the cured product of the magnetic resin composition tends to have a high relative magnetic permeability, a small loss factor (tan ⁇ ), and a large allowable DC superposition current value. Therefore, the magnetic resin composition according to this embodiment is suitably used for parts such as power inductors. Power inductors are used, for example, in power supply circuits such as DC-DC converters. By using the magnetic resin composition according to the present embodiment, a DC-DC converter or the like can be easily made highly functional.
  • the magnetic sheet according to the present embodiment contains a magnetic resin composition. Comprehensively judging the magnetic sheet (sheet-like magnetic resin composition), the liquid magnetic resin composition, and the powdery magnetic resin composition, the magnetic sheet is compared to the liquid or powdery magnetic resin composition. , fillability into narrow gaps, etc., and ease of forming a thin film. Therefore, the magnetic sheet according to this embodiment is suitably used for parts such as power inductors.
  • a magnetic sheet is obtained by molding a magnetic resin composition into a sheet.
  • a magnetic sheet can be obtained by applying a magnetic resin composition to a support and drying by heating. By diluting the magnetic resin composition in advance with a solvent, the viscosity of the magnetic resin composition is reduced and the coatability to the support is improved. The solvent is evaporated and removed by heat drying. The magnetic sheet molded on the support can be peeled off from the support.
  • the flexibility of the magnetic sheet can be improved by increasing the content of the liquid epoxy resin. If flexibility improves, it will become easy to wind a magnetic sheet. On the other hand, as the content of the powdery epoxy resin is increased, the peelability of the magnetic sheet from the support can be improved.
  • the support is not particularly limited, but examples include polyethylene terephthalate (PET) film and polyester film.
  • PET polyethylene terephthalate
  • the thickness of the magnetic sheet is not particularly limited, it is, for example, 10 ⁇ m or more and 300 ⁇ m or less.
  • the magnetic sheet according to the present embodiment is easy to be pressure-molded, so it is excellent in filling narrow gaps and the like.
  • the magnetic sheet also has the advantage that it has a uniform thickness and can be formed into a thin film.
  • the inductor component according to this embodiment includes a coil and a molded body (see, for example, International Publication No. 2019/017236).
  • the compact incorporates at least part of the coil.
  • the molded body is formed of a cured product of a magnetic resin composition.
  • the inductor component is formed using the magnetic resin composition described above, it is possible to reduce magnetic loss and improve DC superimposition characteristics. As a result, it is possible to reduce the size of the inductor component. Further, when the magnetic resin composition contains a coupling agent, the adhesion between the coil and the molded body can be improved.
  • a first aspect is a magnetic resin composition containing a magnetic powder, a thermosetting resin, and a curing agent.
  • the magnetic powder contains carbonyl iron powder having a 50% volume average particle size (D50) of 4.0 ⁇ m or less.
  • the magnetic loss can be reduced, and the DC superimposition characteristics can be improved.
  • the second aspect is the magnetic resin composition based on the first aspect.
  • the content of the magnetic powder is 78% by mass or more and 96% by mass or less with respect to the total solid content of 100% by mass of the magnetic resin composition.
  • the content of the magnetic powder is 78% by mass or more, a decrease in relative magnetic permeability can be suppressed.
  • the magnetic powder content is 96% by mass or less, moldability can be improved.
  • a third aspect is a magnetic resin composition based on the first or second aspect.
  • the content of the carbonyl iron powder is 70% by mass or more and 94% by mass or less with respect to the total solid content of 100 parts by mass of the magnetic resin composition.
  • the content of the carbonyl iron powder is 70% by mass or more, a decrease in relative magnetic permeability can be suppressed. Furthermore, deterioration of DC superimposition characteristics can be suppressed. When the content of the carbonyl iron powder is 94% by mass or less, moldability can be improved.
  • a fourth aspect is a magnetic resin composition based on any one of the first to third aspects.
  • the magnetic powder further contains ferrite powder.
  • the loss factor (tan ⁇ ) of the cured product of the magnetic resin composition can be made smaller.
  • a fifth aspect is a magnetic resin composition based on the fourth aspect.
  • the ferrite powder has a 50% volume average particle diameter (D50) of 0.01 ⁇ m or more and 1.0 ⁇ m or less.
  • the ferrite powder since the ferrite powder has a 50% volume average particle diameter (D50) of 0.01 ⁇ m or more, an increase in surface area can be suppressed and moldability can be improved.
  • the 50% volume average particle diameter (D50) of the ferrite powder is 1.0 ⁇ m or less, an increase in eddy current loss in the particles of the ferrite powder is suppressed, and the loss coefficient (tan ⁇ ) of the cured product of the magnetic resin composition becomes difficult to increase.
  • a sixth aspect is a magnetic resin composition based on the fourth or fifth aspect.
  • the content of the ferrite powder is 10% by mass or more and 20% by mass or less with respect to the total solid content of 100% by mass of the magnetic resin composition.
  • the content of the ferrite powder is 10% by mass or more, the loss factor (tan ⁇ ) of the cured product of the magnetic resin composition can be further reduced.
  • the content of the ferrite powder is 20% by mass or less, it is possible to suppress deterioration of the DC superimposition characteristics of the cured product of the magnetic resin composition.
  • a seventh aspect is a magnetic resin composition based on any one of the first to sixth aspects.
  • the cured product of the magnetic resin composition has a relative magnetic permeability of 8 or more at a frequency of 100 MHz.
  • the magnetic loss can be reduced, and the DC superimposition characteristics can be improved.
  • An eighth aspect is a magnetic resin composition based on any one of the first to seventh aspects.
  • the loss factor at a frequency of 100 MHz of the cured product of the magnetic resin composition is 0.04 or less.
  • the magnetic loss can be reduced, and the DC superimposition characteristics can be improved.
  • a ninth aspect is a magnetic resin composition based on any one of the first to eighth aspects.
  • the cured product of the magnetic resin composition has a DC superposition allowable current value of 15 A or more at a frequency of 100 kHz.
  • the magnetic loss can be reduced, and the DC superimposition characteristics can be improved.
  • a tenth aspect is a magnetic sheet comprising a magnetic resin composition based on any one of the first to ninth aspects.
  • the magnetic loss can be reduced, and the DC superimposition characteristics can be improved.
  • An eleventh aspect is an inductor component comprising a coil and a molded body.
  • the compact incorporates at least part of the coil.
  • the molded body is formed of a cured magnetic resin composition according to any one of the first to ninth aspects.
  • the magnetic loss can be reduced, and the DC superimposition characteristics can be improved.
  • ⁇ Magnetic powder> ⁇ Carbonyl iron powder A (insulated with phosphoric acid, D50: 2.8 ⁇ m, D90: 6.0 ⁇ m, particle shape: spherical) ⁇ Carbonyl iron powder B (insulated with phosphoric acid, D50: 2.3 ⁇ m, D90: 4.0 ⁇ m, particle shape: spherical) ⁇ Carbonyl iron powder C (insulated with phosphoric acid, D50: 4.7 ⁇ m, D90: 9.0 ⁇ m, particle shape: spherical) ⁇ Ferrite powder (D50: 0.25 ⁇ m, particle shape: spherical) - Fe-based amorphous alloy powder (manufactured by Epson Atmix Corporation, trade name "AW2-08/PF-3K", D50: 3.3 ⁇ m, D90: 5.5 ⁇ m, particle shape: spherical).
  • Epoxy resin 1 bisphenol F type epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name “jER 807”)
  • Epoxy resin 2 Polyfunctional epoxy resin (manufactured by Printec Co., Ltd., trade name “TECHMORE VG3101”) - Phenoxy resin: manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., trade name "YP-50”, weight average molecular weight Mw: 60,000 to 80,000.
  • Curing agent 1 dicyandiamide
  • Curing agent 2 imidazole-based curing accelerator (2-ethyl-4-methylimidazole, manufactured by Shikoku Kasei Co., Ltd., trade name "2E4MZ").
  • Coupling agent silane coupling agent (epoxysilane, manufactured by Momentive, trade name “A1871”)
  • Dispersant Polyoxyethylene-laurylamine (manufactured by NOF Corporation, trade name “Nymeen L-202”)
  • Solvent> ⁇ Methyl ethyl ketone ⁇ N,N-dimethylformamide (2) Production (2.1) Magnetic sheet A varnish was obtained (integral blend method). Next, a slurry was obtained by blending the magnetic powder into the above varnish in the blending amount (% by mass) shown in Table 1. Next, this slurry was filtered to remove impurities to obtain a liquid magnetic resin composition.
  • a PET film preliminarily subjected to mold release treatment with silicone was prepared as a support, and the liquid magnetic resin composition was applied to the PET film and dried by heating to form a magnetic sheet having a thickness of 100 ⁇ m. got The volatile content remaining in this magnetic sheet was less than 0.2% by mass.
  • Sample A plurality of the above magnetic sheets were stacked and cured by heating and pressing for 20 minutes at 175°C and 10 MPa under vacuum, and then post-cured by heating at 175°C for 90 minutes to obtain a sample. made.
  • the sample is a ring-shaped hardened material having an outer diameter of 20 mm, an inner diameter of 16 mm, and a thickness of about 3 mm.

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Abstract

The present disclosure addresses the problem of providing a magnetic resin composition that can reduce magnetic loss and improve direct-current superimposition characteristics. According to the present disclosure, a magnetic resin composition contains a magnetic powder, a thermosetting resin, and a curing agent. The magnetic powder includes a carbonyl iron powder that has a 50% volume average particle diameter (D50) of no more than 4.0 μm.

Description

磁性樹脂組成物、磁性シート、及びインダクタ部品Magnetic resin composition, magnetic sheet, and inductor part
　本開示は、一般に磁性樹脂組成物、磁性シート、及びインダクタ部品に関し、より詳細には磁性粉末を含有する磁性樹脂組成物、磁性シート、及びインダクタ部品に関する。 The present disclosure generally relates to magnetic resin compositions, magnetic sheets, and inductor parts, and more specifically to magnetic resin compositions, magnetic sheets, and inductor parts containing magnetic powder.
　特許文献１には、樹脂組成物が開示されている。この樹脂組成物は、（Ａ）熱硬化性樹脂、（Ｂ）硬化剤、（Ｃ）熱可塑性樹脂、（Ｄ）磁性フィラー、及び（Ｅ）無機充填材を含有する。そして、（Ｄ）成分の含有質量をｄ１とし、（Ｅ）成分の含有質量をｅ１とした場合、ｅ１／ｄ１が０．０２以上０．１９以下である。 Patent Document 1 discloses a resin composition. This resin composition contains (A) a thermosetting resin, (B) a curing agent, (C) a thermoplastic resin, (D) a magnetic filler, and (E) an inorganic filler. When the content mass of component (D) is d1 and the content mass of component (E) is e1, e1/d1 is 0.02 or more and 0.19 or less.
　特許文献１の樹脂組成物を熱硬化させた硬化物の、周波数１００ＭＨｚにおける磁性損失は０．０５以下である。 The magnetic loss at a frequency of 100 MHz of the cured product obtained by thermosetting the resin composition of Patent Document 1 is 0.05 or less.
　しかしながら、特許文献１の樹脂組成物の直流重畳特性の良否については不明である。 However, it is unknown whether the DC superimposition characteristics of the resin composition of Patent Document 1 are good or bad.
国際公開第２０１８／１９４１００号WO2018/194100
　本開示の目的は、磁気損失を小さくすることができ、また直流重畳特性を向上させることができる磁性樹脂組成物、磁性シート、及びインダクタ部品を提供することにある。 An object of the present disclosure is to provide a magnetic resin composition, a magnetic sheet, and an inductor component that can reduce magnetic loss and improve DC superimposition characteristics.
　本開示の一態様に係る磁性樹脂組成物は、磁性粉末と、熱硬化性樹脂と、硬化剤と、を含有する。前記磁性粉末が、５０％体積平均粒子径（Ｄ５０）が４．０μｍ以下のカルボニル鉄粉を含む。 A magnetic resin composition according to one aspect of the present disclosure contains magnetic powder, a thermosetting resin, and a curing agent. The magnetic powder contains carbonyl iron powder having a 50% volume average particle size (D50) of 4.0 μm or less.
　本開示の一態様に係る磁性シートは、前記磁性樹脂組成物を含む。 A magnetic sheet according to one aspect of the present disclosure includes the magnetic resin composition.
　本開示の一態様に係るインダクタ部品は、コイルと、前記コイルの少なくとも一部を内蔵する成形体と、を備える。前記成形体が、前記磁性樹脂組成物の硬化物で形成されている。 An inductor component according to one aspect of the present disclosure includes a coil and a molded body that incorporates at least part of the coil. The molded body is formed of a cured product of the magnetic resin composition.
　１．概要
　近年、携帯機器、家電、自動車、及び産業機器等の機器において、小型化、多機能化、高性能化、省電力化がますます進化し続けている。これらの機器に搭載される電子部品においても、より小型、薄型化、及び高性能の要求が求められている。 1. Overview In recent years, devices such as mobile devices, home appliances, automobiles, and industrial devices have continued to evolve toward miniaturization, multifunctionality, high performance, and power saving. Electronic components mounted in these devices are also required to be smaller, thinner, and have higher performance.
　その中でも核となる電源回路においては、ＤＣ－ＤＣコンバータＩＣの高速スイッチング化に伴い、使われるインダクタの低インダクタンス化が進むとともに、より小型、薄型化、低直流抵抗、大電流対応、及び高信頼性が求められている。 Among them, in the power supply circuit, which is the core, along with the high-speed switching of DC-DC converter ICs, the inductance of inductors used has been reduced, and the size and thickness have been reduced, low DC resistance, large current support, and high reliability. sex is required.
　特に直流重畳特性は、パワーインダクタ（電源回路用インダクタ）の性能を左右する特性の１つである。ここで、直流重畳特性とは、インダクタに流れる直流バイアス電流が増大するにつれて、インダクタンスが低下する性質のことである。直流重畳特性は、例えば、直流重畳許容電流値を指標として評価される。直流重畳特性は、直流重畳許容電流値が大きいほど良好である。ここで、直流重畳許容電流値とは、インダクタンスの初期値からの低下率が例えば２０％となったときの電流値である。 In particular, DC superimposition characteristics are one of the characteristics that affect the performance of power inductors (inductors for power supply circuits). Here, the DC superimposition characteristic is the property that the inductance decreases as the DC bias current flowing through the inductor increases. The DC superimposition characteristics are evaluated using, for example, a DC superimposition allowable current value as an index. DC superimposition characteristics are better as the DC superimposition allowable current value is larger. Here, the allowable DC superposition current value is the current value when the rate of decrease from the initial value of the inductance reaches, for example, 20%.
　しかしながら、上述のように、特許文献１の樹脂組成物の直流重畳特性の良否については不明である。そのため、パワーインダクタ等への適用の可否についても不明である。 However, as described above, the quality of the DC superimposition characteristics of the resin composition of Patent Document 1 is unknown. Therefore, it is unclear whether it can be applied to power inductors or the like.
　そこで、本発明者らは、磁気損失を小さくするだけでなく、直流重畳特性も向上させるべく鋭意研究を続けた結果、以下のような磁性樹脂組成物を開発した。 Therefore, the present inventors have continued intensive research not only to reduce the magnetic loss but also to improve the DC superimposition characteristics, and as a result, have developed the following magnetic resin composition.
　すなわち、本実施形態に係る磁性樹脂組成物は、磁性粉末と、熱硬化性樹脂と、硬化剤と、を含有する。磁性粉末が、５０％体積平均粒子径（Ｄ５０）が４．０μｍ以下のカルボニル鉄粉を含む。なお、本発明者らは、開発を進める中で、鉄系アモルファス合金のみでは、直流重畳特性の向上が難しいとの知見も得た。 That is, the magnetic resin composition according to this embodiment contains magnetic powder, a thermosetting resin, and a curing agent. The magnetic powder contains carbonyl iron powder with a 50% volume average particle size (D50) of 4.0 μm or less. In addition, the inventors of the present invention also obtained the knowledge that it is difficult to improve the DC superimposition characteristics only with an iron-based amorphous alloy during the development.
　このように、本発明者らが見出したところによれば、磁性粉末がカルボニル鉄粉を含むことで、直流重畳特性を向上させることができる。さらにカルボニル鉄粉の５０％体積平均粒子径（Ｄ５０）が４．０μｍ以下であることで、磁気損失を小さくすることができる。 Thus, according to the present inventors, the inclusion of the carbonyl iron powder in the magnetic powder can improve the DC bias characteristics. Further, the 50% volume average particle diameter (D50) of the carbonyl iron powder is 4.0 μm or less, so that the magnetic loss can be reduced.
　なお、以下において、「比透磁率」とは、複素比透磁率（μｒ）の実数部（μｒ’）を意味する。ここで、複素比透磁率（μｒ）は、μｒ＝μ／μ０の式で表される（μ：複素透磁率、μ０：真空の透磁率）。複素透磁率（μ）は、μ＝μ’－ｉμ”の式で表される（μ’：実数部、μ”：虚数部、ｉ：虚数単位）。複素比透磁率（μｒ）の実数部（μｒ’）は、μｒ’＝μ’／μ０の式で表される。複素比透磁率（μｒ）の虚数部（μｒ”）は、μｒ”＝μ”／μ０の式で表される。 In the following description, "relative permeability" means the real part (μ r ′) of the complex relative permeability (μ r ) . Here, the complex relative magnetic permeability (μ r ) is represented by the formula μ r =μ/μ 0 (μ: complex magnetic permeability, μ 0 : vacuum magnetic permeability). The complex permeability (μ) is represented by the formula μ=μ′−iμ″ (μ′: real part, μ″: imaginary part, i: imaginary unit). The real part (μ r ') of the complex relative permeability (μ r ) is represented by the formula μ r '=μ'/μ 0 . The imaginary part (μ r ″) of the complex relative permeability (μ r ) is represented by the formula μ r ″=μ″/μ 0 .
　また「磁気損失」とは、損失係数（ｔａｎδ）を意味する。損失係数（ｔａｎδ）は、ｔａｎδ＝μｒ”／μｒ’＝μ”／μ’の式で表される。複素比透磁率（μｒ）の関係式をまとめると以下のとおりである。 Also, "magnetic loss" means a loss coefficient (tan δ). The loss factor (tan δ) is expressed by the formula tan δ=μ r ″/μ r '=μ″/μ′. The relational expression of the complex relative permeability (μ r ) is summarized below.
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
　２．詳細
　（１）磁性樹脂組成物
　本実施形態に係る磁性樹脂組成物は、磁性粉末と、熱硬化性樹脂と、硬化剤と、を含有する。磁性樹脂組成物は、添加剤を更に含有してもよい。磁性樹脂組成物は、溶剤を更に含有してもよい。以下、各成分について説明する。 2. Details (1) Magnetic Resin Composition The magnetic resin composition according to the present embodiment contains magnetic powder, a thermosetting resin, and a curing agent. The magnetic resin composition may further contain additives. The magnetic resin composition may further contain a solvent. Each component will be described below.
　＜磁性粉末＞
　磁性粉末は、磁性を帯びることが可能な粉末状物質である。このように、磁性樹脂組成物が磁性粉末を含有することで、磁気特性を有する硬化物を得ることができる。磁気特性は、磁化された際に示す磁気的な性質である。磁気特性の具体例として、比透磁率及び磁束密度等が挙げられる。 <Magnetic powder>
A magnetic powder is a powdery substance that can be magnetized. In this way, the inclusion of the magnetic powder in the magnetic resin composition makes it possible to obtain a cured product having magnetic properties. Magnetic properties are the magnetic properties exhibited when magnetized. Specific examples of magnetic properties include relative magnetic permeability and magnetic flux density.
　磁性粉末の含有量は、磁性樹脂組成物の固形分合計１００質量％に対して、好ましくは７８質量％以上、より好ましくは８５質量％以上である。磁性粉末の含有量が７８質量％以上であることで、比透磁率の低下を抑制し得る。所望の磁気特性が得られやすくなる。磁性粉末の含有量が８５質量％以上であることで、比透磁率の低下を更に抑制し得る。高い比透磁率が得られやすくなる。なお、磁性樹脂組成物の固形分とは、磁性樹脂組成物から溶剤等の揮発する物質を除いたものを意味する。 The magnetic powder content is preferably 78% by mass or more, more preferably 85% by mass or more, relative to the total solid content of 100% by mass of the magnetic resin composition. When the magnetic powder content is 78% by mass or more, a decrease in relative magnetic permeability can be suppressed. Desired magnetic properties can be easily obtained. When the magnetic powder content is 85% by mass or more, the decrease in relative magnetic permeability can be further suppressed. It becomes easier to obtain a high relative magnetic permeability. The solid content of the magnetic resin composition means the magnetic resin composition excluding volatile substances such as solvents.
　磁性粉末の含有量は、磁性樹脂組成物の固形分合計１００質量％に対して、好ましくは９６質量％以下、より好ましくは９５質量％以下である。磁性粉末の含有量が９６質量％以下であることで、成形性が向上し得る。成形時において流動性が得られやすくなる。磁性粉末の含有量が９５質量％以下であることで、成形性が更に向上し得る。狭小な隙間等に磁性樹脂組成物を充填しやすくなる。 The magnetic powder content is preferably 96% by mass or less, more preferably 95% by mass or less, relative to the total solid content of 100% by mass of the magnetic resin composition. When the magnetic powder content is 96% by mass or less, moldability can be improved. Fluidity is easily obtained during molding. When the magnetic powder content is 95% by mass or less, moldability can be further improved. It becomes easier to fill a narrow gap or the like with the magnetic resin composition.
　本実施形態に係る磁性樹脂組成物の硬化物は、高周波において高い比透磁率を有し得る。高周波の周波数帯域は、例えば、数ＭＨｚ以上数ＧＨｚ以下であり、１００ＭＨｚが含まれる。 A cured product of the magnetic resin composition according to the present embodiment can have a high relative magnetic permeability at high frequencies. The high frequency band is, for example, several MHz or more and several GHz or less, including 100 MHz.
　本実施形態では、磁性粉末は、カルボニル鉄粉を含む。好ましくは、磁性粉末は、フェライト粉を更に含む。 In this embodiment, the magnetic powder contains carbonyl iron powder. Preferably, the magnetic powder further contains ferrite powder.
　≪カルボニル鉄粉≫
　カルボニル鉄粉（ＣＩＰ：Carbonyl Iron Powder）は、純鉄粉である。カルボニル鉄粉は、ペンタカルボニル鉄（Ｆｅ（ＣＯ）５）の熱分解により製造される。熱分解条件によって粒度分布が調整される。カルボニル鉄粉の粒子形状は、好ましくは球状、より好ましくは真球状である。カルボニル鉄粉の化学成分として、Ｆｅ、Ｃ、及びＯ等が挙げられる。カルボニル鉄粉ではＦｅが９５質量％以上を占めている。 ≪Carbonyl iron powder≫
Carbonyl Iron Powder (CIP) is pure iron powder. Carbonyl iron powder is produced by pyrolysis of pentacarbonyl iron (Fe(CO) 5 ). Particle size distribution is controlled by pyrolysis conditions. The particle shape of the carbonyl iron powder is preferably spherical, more preferably spherical. Chemical components of the carbonyl iron powder include Fe, C, O, and the like. In the carbonyl iron powder, Fe accounts for 95% by mass or more.
　カルボニル鉄粉の５０％体積平均粒子径（Ｄ５０）は、好ましくは０．０１μｍ以上、より好ましくは０．５μｍ以上である。なお、「５０％体積平均粒子径（Ｄ５０）」とは、レーザ散乱・回折法に基づく粒度分布測定装置に基づいて測定した粒度分布における積算値５０％での粒径（Ｄ５０）を意味する。 The 50% volume average particle diameter (D50) of the carbonyl iron powder is preferably 0.01 μm or more, more preferably 0.5 μm or more. The term "50% volume average particle size (D50)" means the particle size (D50) at an integrated value of 50% in a particle size distribution measured based on a particle size distribution analyzer based on a laser scattering/diffraction method.
　本実施形態では、カルボニル鉄粉の５０％体積平均粒子径（Ｄ５０）は４．０μｍ以下である。カルボニル鉄粉の５０％体積平均粒子径（Ｄ５０）が４．０μｍを超えると、磁気損失が大きくなるおそれがある。カルボニル鉄粉の５０％体積平均粒子径（Ｄ５０）は、好ましくは３．０μｍ以下である。 In this embodiment, the 50% volume average particle size (D50) of the carbonyl iron powder is 4.0 μm or less. If the 50% volume average particle size (D50) of the carbonyl iron powder exceeds 4.0 μm, magnetic loss may increase. The 50% volume average particle size (D50) of the carbonyl iron powder is preferably 3.0 µm or less.
　上記のように、本実施形態では、磁性粉末がカルボニル鉄粉を含むことで、直流重畳特性を向上させることができる。さらにカルボニル鉄粉の５０％体積平均粒子径（Ｄ５０）が４．０μｍ以下であることで、磁気損失を小さくすることができる。 As described above, in the present embodiment, the magnetic powder contains the carbonyl iron powder, so that the DC superimposition characteristics can be improved. Further, the 50% volume average particle diameter (D50) of the carbonyl iron powder is 4.0 μm or less, so that the magnetic loss can be reduced.
　カルボニル鉄粉の９０％体積平均粒子径（Ｄ９０）は、好ましくは１．０μｍ以上、より好ましくは３．０μｍ以上である。なお、「９０％体積平均粒子径（Ｄ９０）」とは、レーザ散乱・回折法に基づく粒度分布測定装置に基づいて測定した粒度分布における積算値９０％での粒径（Ｄ９０）を意味する。 The 90% volume average particle size (D90) of the carbonyl iron powder is preferably 1.0 µm or more, more preferably 3.0 µm or more. The term "90% volume average particle size (D90)" means the particle size (D90) at an integrated value of 90% in a particle size distribution measured based on a particle size distribution analyzer based on a laser scattering/diffraction method.
　カルボニル鉄粉の９０％体積平均粒子径（Ｄ９０）は、好ましくは９．０μｍ未満、より好ましくは７．０μｍ以下である。カルボニル鉄粉の９０％体積平均粒子径（Ｄ９０）が９．０μｍ以上であると、磁気損失が大きくなるおそれがある。 The 90% volume average particle size (D90) of the carbonyl iron powder is preferably less than 9.0 µm, more preferably 7.0 µm or less. If the 90% volume average particle diameter (D90) of the carbonyl iron powder is 9.0 μm or more, magnetic loss may increase.
　ここで、５０％体積平均粒子径（Ｄ５０）及び９０％体積平均粒子径（Ｄ９０）の測定は、例えば、マイクロトラック・ベル株式会社製の粒子径分布測定装置（型式：ＭＴ３３００）を用いて測定することができる。測定条件は、例えば、粒子透過性を透過モード、溶媒をエタノール、溶媒屈折率を１．３６とする。 Here, the 50% volume average particle size (D50) and 90% volume average particle size (D90) are measured using, for example, a particle size distribution analyzer (model: MT3300) manufactured by Microtrack Bell Co., Ltd. can do. Measurement conditions are, for example, a transmission mode for particle permeability, ethanol as a solvent, and a solvent refractive index of 1.36.
　カルボニル鉄粉は、絶縁処理されていることが好ましい。すなわち、磁性粉末は、絶縁処理カルボニル鉄粉を含むことが好ましい。絶縁処理カルボニル鉄粉は、例えば、リン化合物（リン酸等）又は金属酸化物（シリカ等）を用いて、カルボニル鉄粉の表面を処理することにより得られる。このように、カルボニル鉄粉を絶縁処理することにより、カルボニル鉄粉の粒子間の渦電流損失が低減される。 The carbonyl iron powder is preferably insulated. That is, the magnetic powder preferably contains an insulation-treated carbonyl iron powder. The insulated carbonyl iron powder is obtained by treating the surface of the carbonyl iron powder with, for example, a phosphorus compound (phosphoric acid, etc.) or a metal oxide (silica, etc.). By insulating the carbonyl iron powder in this manner, eddy current loss between particles of the carbonyl iron powder is reduced.
　上記の絶縁処理カルボニル鉄粉は、有機系表面処理剤で表面処理されていてもよい。有機系表面処理剤としては、特に限定されないが、カップリング剤（後述）、及び有機酸等が挙げられる。このように、絶縁処理カルボニル鉄粉が有機系表面処理剤で表面処理されていることにより、熱硬化性樹脂等との相溶性が増し、磁性樹脂組成物における絶縁処理カルボニル鉄粉の分散性を向上させることができる。 The above insulation-treated carbonyl iron powder may be surface-treated with an organic surface treatment agent. Examples of the organic surface treatment agent include, but are not particularly limited to, a coupling agent (described later), an organic acid, and the like. By surface-treating the insulated carbonyl iron powder with an organic surface treatment agent in this manner, compatibility with thermosetting resins and the like is increased, and the dispersibility of the insulated carbonyl iron powder in the magnetic resin composition is improved. can be improved.
　カルボニル鉄粉の含有量は、磁性樹脂組成物の固形分合計１００質量％に対して、好ましくは７０質量％以上、より好ましくは７５質量％以上である。カルボニル鉄粉の含有量が７０質量％以上であることで、比透磁率の低下を抑制し得る。さらに直流重畳特性の低下も抑制し得る。 The content of the carbonyl iron powder is preferably 70% by mass or more, more preferably 75% by mass or more, relative to the total solid content of 100% by mass of the magnetic resin composition. When the content of the carbonyl iron powder is 70% by mass or more, a decrease in relative magnetic permeability can be suppressed. Furthermore, deterioration of DC superimposition characteristics can be suppressed.
　カルボニル鉄粉の含有量は、磁性樹脂組成物の固形分合計１００質量％に対して、好ましくは９４質量％以下、より好ましくは９３質量％以下である。カルボニル鉄粉の含有量が９４質量％以下であることで、成形性が向上し得る。 The content of the carbonyl iron powder is preferably 94% by mass or less, more preferably 93% by mass or less, relative to the total solid content of 100% by mass of the magnetic resin composition. When the content of the carbonyl iron powder is 94% by mass or less, moldability can be improved.
　≪フェライト粉≫
　フェライト粉は、酸化鉄を主成分とするセラミックスの粉末である。フェライトとしては、特に限定されないが、例えば、スピネルフェライト、六方晶フェライト、及びガーネットフェライト等が挙げられる。スピネルフェライトとしては、特に限定されないが、例えば、磁鉄鉱（マグネタイト、Ｆｅ３Ｏ４）等が挙げられる。フェライト粉の粒子形状は、好ましくは球状である。 <<Ferrite powder>>
Ferrite powder is a ceramic powder containing iron oxide as a main component. Examples of ferrite include, but are not particularly limited to, spinel ferrite, hexagonal ferrite, and garnet ferrite. Examples of spinel ferrite include, but are not particularly limited to, magnetite (magnetite, Fe 3 O 4 ). The particle shape of the ferrite powder is preferably spherical.
　フェライト粉は、カルボニル鉄粉に比べて電気絶縁性が高い。そのため、磁性粉末がフェライト粉を更に含むことで、磁性樹脂組成物の硬化物の損失係数（ｔａｎδ）をより小さくすることができる。 Ferrite powder has higher electrical insulation than carbonyl iron powder. Therefore, by including ferrite powder in the magnetic powder, the loss factor (tan δ) of the cured product of the magnetic resin composition can be further reduced.
　フェライト粉は、例えば、無機材料（シリカ等）又はカップリング剤（後述）を用いて、表面処理されていてもよい。このように、フェライト粉が表面処理されていると、熱及び吸湿による電気絶縁性の劣化を抑制したり、磁気特性の変化を抑制したりすることができる。 The ferrite powder may be surface-treated, for example, using an inorganic material (silica, etc.) or a coupling agent (described later). When the ferrite powder is surface-treated in this way, it is possible to suppress the deterioration of the electrical insulation due to heat and moisture absorption, and suppress the change in the magnetic properties.
　磁性粉末がフェライト粉を更に含む場合、フェライト粉の５０％体積平均粒子径（Ｄ５０）は、カルボニル鉄粉の５０％体積平均粒子径（Ｄ５０）よりも小さいことが好ましい。具体的には、フェライト粉の５０％体積平均粒子径（Ｄ５０）は、好ましくは０．０１μｍ以上、より好ましくは０．１μｍ以上である。フェライト粉の５０％体積平均粒子径（Ｄ５０）が０．０１μｍ以上であることで、表面積の増加が抑制され、成形性が向上し得る。フェライト粉の５０％体積平均粒子径（Ｄ５０）は、好ましくは１．０μｍ以下である。フェライト粉の５０％体積平均粒子径（Ｄ５０）が１．０μｍ以下であることで、フェライト粉の粒子が、カルボニル鉄粉の粒子間に形成される隙間を埋めることができる。これにより、カルボニル鉄粉の粒子同士の接触が抑制され、最密充填構造が形成されやすくなる。またフェライト粉の粒子内の渦電流損失の増加が抑えられ、磁性樹脂組成物の硬化物の損失係数（ｔａｎδ）が増加しにくくなる。 When the magnetic powder further contains ferrite powder, the 50% volume average particle size (D50) of the ferrite powder is preferably smaller than the 50% volume average particle size (D50) of the carbonyl iron powder. Specifically, the 50% volume average particle diameter (D50) of the ferrite powder is preferably 0.01 μm or more, more preferably 0.1 μm or more. When the 50% volume average particle diameter (D50) of the ferrite powder is 0.01 μm or more, an increase in surface area can be suppressed, and moldability can be improved. The 50% volume average particle diameter (D50) of the ferrite powder is preferably 1.0 μm or less. When the 50% volume average particle diameter (D50) of the ferrite powder is 1.0 μm or less, the ferrite powder particles can fill the gaps formed between the carbonyl iron powder particles. This suppresses the contact between the particles of the carbonyl iron powder, facilitating the formation of a close-packed structure. Moreover, an increase in eddy current loss in the particles of the ferrite powder is suppressed, and the loss factor (tan δ) of the cured product of the magnetic resin composition is less likely to increase.
　フェライト粉の含有量は、磁性樹脂組成物の固形分合計１００質量％に対して、好ましくは５質量％以上、より好ましくは１０質量％以上である。フェライト粉の含有量が５質量％以上であることで、磁性樹脂組成物の硬化物の損失係数（ｔａｎδ）をより小さくすることができる。フェライト粉の含有量は、磁性樹脂組成物の固形分合計１００質量％に対して、好ましくは３０質量％以下、より好ましくは２０質量％以下である。フェライト粉の含有量が３０質量％以下であることで、磁性樹脂組成物の硬化物の直流重畳特性の低下を抑制し得る。 The ferrite powder content is preferably 5% by mass or more, more preferably 10% by mass or more, relative to the total solid content of 100% by mass of the magnetic resin composition. When the content of the ferrite powder is 5% by mass or more, the loss factor (tan δ) of the cured product of the magnetic resin composition can be made smaller. The ferrite powder content is preferably 30% by mass or less, more preferably 20% by mass or less, relative to the total solid content of 100% by mass of the magnetic resin composition. When the content of the ferrite powder is 30% by mass or less, it is possible to suppress deterioration of the DC superimposition characteristics of the cured product of the magnetic resin composition.
　＜熱硬化性樹脂＞
　熱硬化性樹脂としては、特に限定されないが、例えば、エポキシ樹脂、フェノキシ樹脂、フェノール樹脂、シリコーン樹脂、アクリル樹脂、ウレタン樹脂、ポリイミド樹脂、ポリフェニレンエーテル樹脂、ベンゾオキサジン樹脂、ビスマレイミド樹脂、フッ素樹脂、及び有機リン酸化合物等を挙げることができる。 <Thermosetting resin>
Examples of thermosetting resins include, but are not limited to, epoxy resins, phenoxy resins, phenol resins, silicone resins, acrylic resins, urethane resins, polyimide resins, polyphenylene ether resins, benzoxazine resins, bismaleimide resins, fluorine resins, and organic phosphoric acid compounds.
　熱硬化性樹脂は、エポキシ樹脂及びフェノキシ樹脂のうち少なくとも一方を含むことが好ましい。これにより、磁性樹脂組成物の成形時における流動性を向上させることができる。特に熱硬化性樹脂がエポキシ樹脂を含む場合には、磁性樹脂組成物の硬化物の接着性、及び寸法安定性を向上させることができる。また磁性樹脂組成物の配合設計の自由度を高めることもできる。エポキシ樹脂の含有量は、磁性樹脂組成物の固形分合計１００質量％に対して、好ましくは３質量％以上である。エポキシ樹脂の含有量は、磁性樹脂組成物の固形分合計１００質量％に対して、好ましくは１５質量％以下である。一方、熱硬化性樹脂がフェノキシ樹脂を含む場合には、磁性樹脂組成物の硬化物の曲げ特性（可撓性等）を向上させることができる。フェノキシ樹脂の含有量は、磁性樹脂組成物の固形分合計１００質量％に対して、好ましくは２質量％以下である。 The thermosetting resin preferably contains at least one of epoxy resin and phenoxy resin. This can improve the fluidity of the magnetic resin composition during molding. Especially when the thermosetting resin contains an epoxy resin, the adhesiveness and dimensional stability of the cured product of the magnetic resin composition can be improved. It is also possible to increase the degree of freedom in designing the formulation of the magnetic resin composition. The content of the epoxy resin is preferably 3% by mass or more with respect to the total solid content of 100% by mass of the magnetic resin composition. The content of the epoxy resin is preferably 15% by mass or less with respect to the total solid content of 100% by mass of the magnetic resin composition. On the other hand, when the thermosetting resin contains a phenoxy resin, it is possible to improve the bending properties (such as flexibility) of the cured product of the magnetic resin composition. The content of the phenoxy resin is preferably 2% by mass or less with respect to the total solid content of 100% by mass of the magnetic resin composition.
　エポキシ樹脂は、１分子内に少なくとも１つのエポキシ基を有する化合物である。エポキシ樹脂としては、特に限定されないが、例えば、フェノールノボラック型エポキシ樹脂、クレゾールノボラック型エポキシ樹脂等のアルキルフェノールノボラック型エポキシ樹脂；ナフトールノボラック型エポキシ樹脂；フェニレン骨格、ビフェニレン骨格等を有するフェノールアラルキル型エポキシ樹脂；ビフェニルアラルキル型エポキシ樹脂；フェニレン骨格、ビフェニレン骨格等を有するナフトールアラルキル型エポキシ樹脂；トリフェノールメタン型エポキシ樹脂、アルキル変性トリフェノールメタン型エポキシ樹脂等の多官能型エポキシ樹脂；トリフェニルメタン型エポキシ樹脂；テトラキスフェノールエタン型エポキシ樹脂；ジシクロペンタジエン型エポキシ樹脂；スチルベン型エポキシ樹脂；ビスフェノールＡ型エポキシ樹脂、ビスフェノールＦ型エポキシ樹脂等のビスフェノール型エポキシ樹脂；ビフェニル型エポキシ樹脂；ナフタレン型エポキシ樹脂；脂環式エポキシ樹脂；ビスフェノールＡ型ブロム含有エポキシ樹脂等のブロム含有エポキシ樹脂；ジアミノジフェニルメタンやイソシアヌル酸等のポリアミンとエピクロルヒドリンとの反応により得られるグリシジルアミン型エポキシ樹脂；並びにフタル酸やダイマー酸等の多塩基酸とエピクロルヒドリンとの反応により得られるグリシジルエステル型エポキシ樹脂等が挙げられる。 Epoxy resin is a compound having at least one epoxy group in one molecule. Examples of epoxy resins include, but are not limited to, alkylphenol novolac type epoxy resins such as phenol novolak type epoxy resins and cresol novolak type epoxy resins; naphthol novolak type epoxy resins; phenol aralkyl type epoxy resins having a phenylene skeleton, biphenylene skeleton, etc. biphenyl aralkyl type epoxy resins; naphthol aralkyl type epoxy resins having a phenylene skeleton, biphenylene skeleton, etc.; polyfunctional epoxy resins such as triphenol methane type epoxy resins and alkyl-modified triphenol methane type epoxy resins; triphenylmethane type epoxy resins tetrakisphenol ethane type epoxy resin; dicyclopentadiene type epoxy resin; stilbene type epoxy resin; bisphenol type epoxy resin such as bisphenol A type epoxy resin and bisphenol F type epoxy resin; biphenyl type epoxy resin; naphthalene type epoxy resin; formula epoxy resins; bromine-containing epoxy resins such as bisphenol A-type bromine-containing epoxy resins; glycidylamine-type epoxy resins obtained by reacting polyamines such as diaminodiphenylmethane and isocyanuric acid with epichlorohydrin; and polybasic compounds such as phthalic acid and dimer acid Glycidyl ester type epoxy resins obtained by reacting an acid with epichlorohydrin, and the like.
　エポキシ樹脂は、液状であっても、粉状であってもよい。液状のエポキシ樹脂を用いると、磁性樹脂組成物を液状にしやすくなる。液状のエポキシ樹脂の使用量を調整することで、液状の磁性樹脂組成物の粘度及び流動性を調整することができる。一方、粉状のエポキシ樹脂を用いると、磁性樹脂組成物を粉状にしやすくなる。粉状のエポキシ樹脂の使用量を調整することで、粉状の磁性樹脂組成物の長期保管でのブロッキングを抑制することができる。さらに液状のエポキシ樹脂及び粉状のエポキシ樹脂を併用すると、磁性樹脂組成物を半固形又は固形のシート状にしやすくなる。 The epoxy resin may be liquid or powdery. The use of a liquid epoxy resin makes it easier to liquefy the magnetic resin composition. By adjusting the amount of the liquid epoxy resin used, the viscosity and fluidity of the liquid magnetic resin composition can be adjusted. On the other hand, if a powdery epoxy resin is used, the magnetic resin composition can be easily pulverized. By adjusting the amount of the powdery epoxy resin used, blocking during long-term storage of the powdery magnetic resin composition can be suppressed. Further, when a liquid epoxy resin and a powdery epoxy resin are used together, the magnetic resin composition can be easily made into a semi-solid or solid sheet.
　フェノキシ樹脂は、ビスフェノールＡとエピクロルヒドリンとの縮合反応により、直鎖状に高分子化した樹脂である。フェノキシ樹脂は、末端にエポキシ基及び／又は水酸基を有しうる。フェノキシ樹脂の重量平均分子量（Ｍｗ）は、５０，０００～１００，０００であることが好ましく、６０，０００～８０，０００であることがより好ましい。 A phenoxy resin is a linearly polymerized resin through a condensation reaction between bisphenol A and epichlorohydrin. The phenoxy resin may have terminal epoxy groups and/or hydroxyl groups. The weight average molecular weight (Mw) of the phenoxy resin is preferably 50,000 to 100,000, more preferably 60,000 to 80,000.
　磁性樹脂組成物は、前記以外の硬化性樹脂を含有してもよい。磁性樹脂組成物は、例えば、光硬化性樹脂を含有してもよい。 The magnetic resin composition may contain curable resins other than those mentioned above. The magnetic resin composition may contain, for example, a photocurable resin.
　＜硬化剤＞
　硬化剤は、磁性樹脂組成物における硬化性成分を硬化させる機能を有する。本実施形態では、硬化剤は、磁性樹脂組成物における熱硬化性樹脂を硬化させる。 <Curing agent>
The curing agent has a function of curing the curable component in the magnetic resin composition. In this embodiment, the curing agent cures the thermosetting resin in the magnetic resin composition.
　硬化剤は、硬化促進剤、硬化触媒、及び硬化助剤も含む。硬化剤としては、特に限定されないが、例えば、フェノール系硬化剤、酸無水物系硬化剤、脂肪族アミン系硬化剤、芳香族アミン系硬化剤、イミダゾール系硬化促進剤、第３級アミン類、及びリン化合物等が挙げられる。 Curing agents also include curing accelerators, curing catalysts, and curing aids. The curing agent is not particularly limited, but for example, phenolic curing agents, acid anhydride curing agents, aliphatic amine curing agents, aromatic amine curing agents, imidazole curing accelerators, tertiary amines, and phosphorus compounds.
　硬化剤の含有量は、磁性樹脂組成物の固形分合計１００質量％に対して、好ましくは０．０１質量％以上である。硬化剤の含有量は、磁性樹脂組成物の固形分合計１００質量％に対して、好ましくは３質量％以下である。 The content of the curing agent is preferably 0.01% by mass or more with respect to the total solid content of 100% by mass of the magnetic resin composition. The content of the curing agent is preferably 3% by mass or less with respect to 100% by mass of the total solid content of the magnetic resin composition.
　＜添加剤＞
　添加剤は、磁性樹脂組成物に各種の機能を付与し得る。添加剤としては、特に限定されないが、例えば、カップリング剤、分散剤、低弾性付与剤（エラストマー）、顔料（着色剤）、酸化防止剤、難燃剤、非磁性フィラー、消泡剤、及びレベリング剤等が挙げられる。 <Additive>
Additives can impart various functions to the magnetic resin composition. Examples of additives include, but are not limited to, coupling agents, dispersants, low-elasticity imparting agents (elastomers), pigments (colorants), antioxidants, flame retardants, non-magnetic fillers, antifoaming agents, and leveling agents. agents and the like.
　≪カップリング剤≫
　カップリング剤は、磁性粉末と熱硬化性樹脂等との間の界面形成のために使用される。カップリング剤は、磁性粉末と熱硬化性樹脂等との親和性を向上させる。 ≪Coupling agent≫
A coupling agent is used to form an interface between the magnetic powder and the thermosetting resin or the like. A coupling agent improves the affinity between the magnetic powder and the thermosetting resin or the like.
　カップリング剤としては、特に限定されないが、例えば、シランカップリング剤、チタネートカップリング剤、アルミニウムカップリング剤、アルミニウム／ジルコニウムシランカップリング剤等が挙げられる。シランカップリング剤としては、特に限定されないが、例えば、γ－グリシドキシプロピルトリメトキシシランに代表されるエポキシ基を有するシランカップリング剤；γ－アミノプロピルトリメトキシシラン、Ｎ－β（アミノエチル）－γ－アミノプロピルトリメトキシシラン等のアミノシラン；Ｎ－フェニル－γ－アミノプロピルトリメトキシシラン等のアミノフェニルシラン；３－メルカプトプロピルトリメトキシシランに代表されるメルカプトシラン；ウレイドシラン、アルキルシラン、ビニルシラン、イソシアヌレートシラン、及びアクリルシラン等が挙げられる。 The coupling agent is not particularly limited, but includes, for example, silane coupling agents, titanate coupling agents, aluminum coupling agents, aluminum/zirconium silane coupling agents, and the like. Examples of the silane coupling agent include, but are not limited to, epoxy group-containing silane coupling agents represented by γ-glycidoxypropyltrimethoxysilane; γ-aminopropyltrimethoxysilane, N-β (aminoethyl )-γ-aminopropyltrimethoxysilane and other aminosilanes; N-phenyl-γ-aminopropyltrimethoxysilane and other aminophenylsilanes; mercaptosilanes typified by 3-mercaptopropyltrimethoxysilane; ureidosilanes, alkylsilanes, vinyl silanes, isocyanurate silanes, acrylic silanes, and the like.
　カップリング剤の含有量は、磁性粉末１００質量部に対して、好ましくは０．０１質量部以上、より好ましくは０．１質量部以上である。カップリング剤の含有量は、磁性粉末１００質量部に対して、好ましくは５．０質量部以下、より好ましくは１．０質量部以下である。 The content of the coupling agent is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, relative to 100 parts by mass of the magnetic powder. The content of the coupling agent is preferably 5.0 parts by mass or less, more preferably 1.0 parts by mass or less, relative to 100 parts by mass of the magnetic powder.
　カップリング剤の使用方法としては、特に限定されないが、直接処理法、及びインテグラルブレンド法が挙げられる。直接処理法は、カップリング剤で処理した磁性粉末を熱硬化性樹脂等に混合する方法である。一方、インテグラルブレンド法は、カップリング剤を、磁性粉末と熱硬化性樹脂等との混合物中に添加する方法である。 The method of using the coupling agent is not particularly limited, but includes the direct treatment method and the integral blend method. The direct treatment method is a method in which magnetic powder treated with a coupling agent is mixed with a thermosetting resin or the like. On the other hand, the integral blend method is a method of adding a coupling agent to a mixture of a magnetic powder and a thermosetting resin or the like.
　磁性樹脂組成物がカップリング剤を含有することで、磁性粉末と熱硬化性樹脂等との濡れ性が改善され、磁性粉末の分散性が向上し得る。 By including a coupling agent in the magnetic resin composition, the wettability between the magnetic powder and the thermosetting resin can be improved, and the dispersibility of the magnetic powder can be improved.
　≪分散剤≫
　分散剤は、主として磁性粉末の分散性を向上させるために使用される。 ≪Dispersant≫
Dispersants are mainly used to improve the dispersibility of magnetic powder.
　分散剤としては、特に限定されないが、例えば、ポリオキシエチレン－ラウリルアミン、リン系界面活性剤、長鎖脂肪酸、長鎖脂肪酸金属塩、ポリカルボン酸アンモニウム、ポリカルボン酸ナトリウム、ナフタレンスルホン酸ナトリウム等が挙げられる。リン系界面活性剤としては、特に限定されないが、例えば、リン酸エステル等が挙げられる。リン酸エステルは、長鎖アルキル基、ポリエステル基、及びアルキルエーテル基の少なくともいずれかを有していてもよい。 Dispersants are not particularly limited, but examples include polyoxyethylene-laurylamine, phosphorus-based surfactants, long-chain fatty acids, long-chain fatty acid metal salts, ammonium polycarboxylate, sodium polycarboxylate, sodium naphthalenesulfonate, and the like. are mentioned. Phosphorus-based surfactants are not particularly limited, but include, for example, phosphate esters and the like. The phosphate ester may have at least one of a long-chain alkyl group, a polyester group, and an alkyl ether group.
　分散剤は酸性でも塩基性でもよい。酸性分散剤としては、特に限定されないが、例えば、スルホン酸基、又はカルボキシ基等を有する界面活性剤が挙げられる。塩基性分散剤としては、特に限定されないが、例えば、リン酸エステルのアミン塩等が挙げられる。 The dispersant may be acidic or basic. Examples of the acidic dispersant include, but are not particularly limited to, surfactants having a sulfonic acid group, a carboxyl group, or the like. Examples of the basic dispersant include, but are not particularly limited to, amine salts of phosphoric acid esters.
　分散剤の含有量は、磁性粉末１００質量部に対して、好ましくは０．０１質量部以上、より好ましくは０．１質量部以上である。分散剤の含有量は、磁性粉末１００質量部に対して、好ましくは５．０質量部以下、より好ましくは１．０質量部以下である。 The content of the dispersant is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, relative to 100 parts by mass of the magnetic powder. The content of the dispersant is preferably 5.0 parts by mass or less, more preferably 1.0 parts by mass or less, relative to 100 parts by mass of the magnetic powder.
　分散剤の使用方法としては、カップリング剤の使用方法と同様に、直接処理法、及びインテグラルブレンド法が挙げられる。分散剤をカップリング剤と併用することにより、両者の効果を増大させることができる。 As for the method of using the dispersing agent, the direct processing method and the integral blending method can be mentioned in the same way as the method of using the coupling agent. By using the dispersant together with the coupling agent, the effects of both can be enhanced.
　≪低弾性付与剤≫
　低弾性付与剤は、磁性樹脂組成物の硬化物の弾性率を低減する。これにより、硬化物中の応力が低減され、硬化物に柔軟性が付与され、硬化物を強靭化することができる。低弾性付与剤は、フェノキシ樹脂の代替物として用いてもよい。低弾性付与剤としては、特に限定されないが、例えば、熱可塑性エラストマー、コアシェルゴム、及びシリコーンゴム等が挙げられる。熱可塑性エラストマーとしては、スチレン系、オレフィン系、ウレタン系、アミド系、エステル系、ＰＶＣ系、及びフッ素系等が挙げられる。 ≪Low elasticity imparting agent≫
The low-elasticity imparting agent reduces the elastic modulus of the cured product of the magnetic resin composition. This reduces stress in the cured product, imparts flexibility to the cured product, and toughens the cured product. A low modulus imparting agent may be used as a substitute for the phenoxy resin. Examples of the low-elasticity-imparting agent include, but are not limited to, thermoplastic elastomers, core-shell rubbers, and silicone rubbers. Examples of thermoplastic elastomers include styrene-based, olefin-based, urethane-based, amide-based, ester-based, PVC-based, and fluorine-based elastomers.
　≪顔料≫
　顔料は、磁性樹脂組成物の着色に用いられる。顔料は、無機顔料と、有機顔料とに大別される。無機顔料としては、特に限定されないが、例えば、カーボンブラック、チタン白（二酸化チタン）、及び酸化鉄赤（ベンガラ）等が挙げられる。有機顔料としては、特に限定されないが、例えば、アゾ顔料、及び多環顔料等が挙げられる。 ≪Pigments≫
A pigment is used for coloring the magnetic resin composition. Pigments are roughly classified into inorganic pigments and organic pigments. Examples of inorganic pigments include, but are not limited to, carbon black, titanium white (titanium dioxide), and iron oxide red (red iron oxide). Examples of organic pigments include, but are not limited to, azo pigments and polycyclic pigments.
　≪酸化防止剤≫
　酸化防止剤は、磁性樹脂組成物の酸化を抑制する。酸化が抑制されると、磁性樹脂組成物の硬化物の耐熱性が向上し得る。酸化防止剤は、ラジカル捕捉剤と、過酸化物分解剤とに大別される。 ≪Antioxidant≫
The antioxidant suppresses oxidation of the magnetic resin composition. When oxidation is suppressed, the heat resistance of the cured product of the magnetic resin composition can be improved. Antioxidants are roughly classified into radical scavengers and peroxide decomposers.
　ラジカル捕捉剤としては、特に限定されないが、例えば、フェノール系酸化防止剤、及び芳香族アミン系酸化防止剤等が挙げられる。特にフェノール系酸化防止剤は、熱酸化防止機能及び耐変色性に優れている。フェノール系酸化防止剤としては、特に限定されないが、例えば、ヒンダードフェノール系酸化防止剤等が挙げられる。 The radical scavenger is not particularly limited, but includes, for example, phenol-based antioxidants and aromatic amine-based antioxidants. In particular, phenolic antioxidants are excellent in thermal antioxidant function and discoloration resistance. Phenolic antioxidants are not particularly limited, but include, for example, hindered phenol antioxidants.
　過酸化物分解剤としては、特に限定されないが、例えば、硫黄系酸化防止剤、及びリン系酸化防止剤等が挙げられる。 The peroxide decomposer is not particularly limited, but includes, for example, sulfur-based antioxidants and phosphorus-based antioxidants.
　≪難燃剤≫
　難燃剤は、磁性樹脂組成物及びその硬化物に難燃性を付与する。難燃剤としては、特に限定されないが、例えば、ハロゲン系難燃剤（臭素系難燃剤等）、及びリン系難燃剤等が挙げられる。 ≪Flame retardant≫
The flame retardant imparts flame retardancy to the magnetic resin composition and its cured product. The flame retardant is not particularly limited, but examples thereof include halogen-based flame retardants (bromine-based flame retardants, etc.), phosphorus-based flame retardants, and the like.
　ハロゲン系難燃剤は、好ましくは、エチレンジペンタブロモベンゼン、エチレンビステトラブロモイミド、デカブロモジフェニルオキサイド、及びテトラデカブロモジフェノキシベンゼンのうちの少なくともいずれかを含む。これらの融点は高いため（例えば３００℃以上）、高温時におけるハロゲンの脱離を抑制でき、磁性樹脂組成物の硬化物の耐熱性の低下を抑制できると考えられる。 The halogen-based flame retardant preferably contains at least one of ethylenedipentabromobenzene, ethylenebistetrabromoimide, decabromodiphenyloxide, and tetradecabromodiphenoxybenzene. Since the melting points of these materials are high (for example, 300° C. or higher), it is thought that detachment of halogen at high temperatures can be suppressed, and deterioration of the heat resistance of the cured product of the magnetic resin composition can be suppressed.
　一方、リン系難燃剤は、ハロゲンフリーに有利である。リン系難燃剤としては、特に限定されないが、例えば、リン酸エステル系難燃剤、ホスファゼン系難燃剤、ビスジフェニルホスフィンオキサイド系難燃剤、及びホスフィン酸塩系難燃剤が挙げられる。リン酸エステル系難燃剤としては、特に限定されないが、例えば、ジキシレニルホスフェートの縮合リン酸エステル等が挙げられる。ホスファゼン系難燃剤としては、特に限定されないが、例えば、フェノキシホスファゼン等が挙げられる。ビスジフェニルホスフィンオキサイド系難燃剤としては、特に限定されないが、例えば、キシリレンビスジフェニルホスフィンオキサイド等が挙げられる。 On the other hand, phosphorus-based flame retardants are advantageous for halogen-free. Phosphorus-based flame retardants are not particularly limited, but include, for example, phosphate-based flame retardants, phosphazene-based flame retardants, bisdiphenylphosphine oxide-based flame retardants, and phosphinate-based flame retardants. Examples of the phosphate ester-based flame retardant include, but are not limited to, condensed phosphate of dixylenyl phosphate. Examples of the phosphazene-based flame retardant include, but are not particularly limited to, phenoxyphosphazene. The bisdiphenylphosphine oxide-based flame retardant is not particularly limited, but includes, for example, xylylenebisdiphenylphosphine oxide.
　≪非磁性フィラー≫
　非磁性フィラーは、磁性を帯びないフィラーである。非磁性フィラーは、例えば、磁性樹脂組成物の硬化物の線膨張係数を低減したり、吸湿性を低減したり、上記硬化物に難燃性を付与したりすることができる。非磁性フィラーとしては、特に限定されないが、例えば、シリカ（二酸化ケイ素）、アルミナ（酸化アルミニウム）、タルク、マイカ、クレイ、チタニア（二酸化チタン）、水酸化アルミニウム、及び水酸化マグネシウム等が挙げられる。水酸化アルミニウム及び水酸化マグネシウムは、難燃剤としても機能し得る。 ≪Non-magnetic filler≫
A non-magnetic filler is a filler that does not have magnetism. The nonmagnetic filler can, for example, reduce the coefficient of linear expansion of the cured product of the magnetic resin composition, reduce the hygroscopicity, and impart flame retardancy to the cured product. Examples of non-magnetic fillers include, but are not limited to, silica (silicon dioxide), alumina (aluminum oxide), talc, mica, clay, titania (titanium dioxide), aluminum hydroxide, and magnesium hydroxide. Aluminum hydroxide and magnesium hydroxide can also function as flame retardants.
　＜溶剤＞
　溶剤は、磁性樹脂組成物の希釈に用いられる。これにより、磁性樹脂組成物をシート状に成形しやすくなる。 <Solvent>
A solvent is used for diluting the magnetic resin composition. This makes it easier to mold the magnetic resin composition into a sheet.
　溶剤としては、特に限定されないが、例えば、ケトン系溶剤、Ｎ，Ｎ－ジメチルホルムアミド、ジメチルアセトアミド、及びトルエン等が挙げられる。ケトン系溶剤としては、特に限定されないが、例えば、メチルエチルケトン、アセトン、メチルイソブチルケトン、及びシクロヘキサノン等が挙げられる。 Examples of solvents include, but are not limited to, ketone solvents, N,N-dimethylformamide, dimethylacetamide, and toluene. Examples of the ketone-based solvent include, but are not particularly limited to, methyl ethyl ketone, acetone, methyl isobutyl ketone, cyclohexanone, and the like.
　＜特性＞
　本実施形態に係る磁性樹脂組成物は、シート状、液状、又は粉状をなす。シート状の磁性樹脂組成物は、磁性シートである。磁性シートについては後述する。液状の磁性樹脂組成物は、成形時において低粘度であるため、狭小な隙間等への充填性に優れている。一方、粉状の磁性樹脂組成物は、加圧可能であるため、狭小な隙間等への充填性を向上させることができる。 <Characteristics>
The magnetic resin composition according to this embodiment is sheet-like, liquid-like, or powder-like. The sheet-shaped magnetic resin composition is a magnetic sheet. The magnetic sheet will be described later. Since the liquid magnetic resin composition has a low viscosity at the time of molding, it is excellent in filling narrow gaps and the like. On the other hand, since the powdery magnetic resin composition can be pressurized, it is possible to improve filling properties in narrow gaps and the like.
　本実施形態に係る磁性樹脂組成物は、以下のような特性を有し得る。 The magnetic resin composition according to this embodiment can have the following characteristics.
　磁性樹脂組成物の硬化物の周波数１００ＭＨｚにおける比透磁率は、好ましくは８以上、より好ましくは９以上である。比透磁率は大きいほど好ましい。これにより、直流重畳特性が向上しやすくなる。比透磁率の上限は、特に限定されないが、例えば、１００以下である。 The cured product of the magnetic resin composition preferably has a relative magnetic permeability of 8 or more, more preferably 9 or more at a frequency of 100 MHz. The higher the relative magnetic permeability, the better. This makes it easier to improve the DC superimposition characteristics. Although the upper limit of the relative magnetic permeability is not particularly limited, it is 100 or less, for example.
　磁性樹脂組成物の硬化物の周波数１００ＭＨｚにおける損失係数（ｔａｎδ）は、好ましくは０．０４以下、より好ましくは０．０３以下である。これにより、熱損失を小さくすることができる。損失係数（ｔａｎδ）は小さいほど好ましい。損失係数（ｔａｎδ）の下限は、好ましくは０．００１以上、より好ましくは０．０１以上である。 The loss factor (tan δ) at a frequency of 100 MHz of the cured product of the magnetic resin composition is preferably 0.04 or less, more preferably 0.03 or less. Thereby, heat loss can be reduced. A smaller loss factor (tan δ) is more preferable. The lower limit of the loss factor (tan δ) is preferably 0.001 or more, more preferably 0.01 or more.
　磁性樹脂組成物の硬化物の周波数１００ｋＨｚにおける直流重畳許容電流値は、好ましくは１５Ａ以上、より好ましくは１６Ａ以上である。直流重畳許容電流値は大きいほど好ましい。直流重畳許容電流値の上限は、特に限定されないが、例えば、５０Ａ以下である。 The DC superposition allowable current value of the cured product of the magnetic resin composition at a frequency of 100 kHz is preferably 15 A or more, more preferably 16 A or more. It is preferable that the DC superimposition allowable current value is as large as possible. The upper limit of the DC superposition allowable current value is not particularly limited, but is, for example, 50 A or less.
　本実施形態に係る磁性樹脂組成物は、高周波での磁気特性に優れている。すなわち、磁性樹脂組成物の硬化物は、比透磁率が大きく、損失係数（ｔａｎδ）が小さく、直流重畳許容電流値が大きくなりやすい。したがって、本実施形態に係る磁性樹脂組成物は、パワーインダクタ等の部品に好適に用いられる。パワーインダクタは、例えば、ＤＣ－ＤＣコンバータ等の電源回路に用いられる。本実施形態に係る磁性樹脂組成物を用いると、ＤＣ－ＤＣコンバータ等を容易に高機能化することができる。 The magnetic resin composition according to this embodiment has excellent magnetic properties at high frequencies. That is, the cured product of the magnetic resin composition tends to have a high relative magnetic permeability, a small loss factor (tan δ), and a large allowable DC superposition current value. Therefore, the magnetic resin composition according to this embodiment is suitably used for parts such as power inductors. Power inductors are used, for example, in power supply circuits such as DC-DC converters. By using the magnetic resin composition according to the present embodiment, a DC-DC converter or the like can be easily made highly functional.
　（２）磁性シート
　本実施形態に係る磁性シートは、磁性樹脂組成物を含む。磁性シート（シート状の磁性樹脂組成物）、液状の磁性樹脂組成物、及び粉状の磁性樹脂組成物を総合的に判断すると、液状又は粉状の磁性樹脂組成物に比べて、磁性シートは、狭小な隙間等への充填性、及び薄膜の形成しやすさ等の点で、より優れている。したがって、本実施形態に係る磁性シートは、パワーインダクタ等の部品に好適に用いられる。 (2) Magnetic Sheet The magnetic sheet according to the present embodiment contains a magnetic resin composition. Comprehensively judging the magnetic sheet (sheet-like magnetic resin composition), the liquid magnetic resin composition, and the powdery magnetic resin composition, the magnetic sheet is compared to the liquid or powdery magnetic resin composition. , fillability into narrow gaps, etc., and ease of forming a thin film. Therefore, the magnetic sheet according to this embodiment is suitably used for parts such as power inductors.
　磁性シートは、磁性樹脂組成物をシート状に成形することにより得られる。具体的には、磁性樹脂組成物を支持体に塗布し、加熱乾燥させることにより磁性シートを得ることができる。あらかじめ磁性樹脂組成物を溶剤で希釈しておけば、磁性樹脂組成物の粘度が低減し、支持体への塗布性が向上する。溶剤は、加熱乾燥により蒸発して除去される。支持体上に成形された磁性シートは、支持体から剥離可能である。 A magnetic sheet is obtained by molding a magnetic resin composition into a sheet. Specifically, a magnetic sheet can be obtained by applying a magnetic resin composition to a support and drying by heating. By diluting the magnetic resin composition in advance with a solvent, the viscosity of the magnetic resin composition is reduced and the coatability to the support is improved. The solvent is evaporated and removed by heat drying. The magnetic sheet molded on the support can be peeled off from the support.
　ここで、磁性樹脂組成物が液状のエポキシ樹脂及び粉状のエポキシ樹脂を含有する場合、液状のエポキシ樹脂の含有量を増加させるほど、磁性シートの可撓性を向上させることができる。可撓性が向上すれば、磁性シートを巻回しやすくなる。一方、粉状のエポキシ樹脂の含有量を増加させるほど、支持体からの磁性シートの剥離性を向上させることができる。 Here, when the magnetic resin composition contains a liquid epoxy resin and a powdery epoxy resin, the flexibility of the magnetic sheet can be improved by increasing the content of the liquid epoxy resin. If flexibility improves, it will become easy to wind a magnetic sheet. On the other hand, as the content of the powdery epoxy resin is increased, the peelability of the magnetic sheet from the support can be improved.
　支持体としては、特に限定されないが、例えば、ポリエチレンテレフタレート（ＰＥＴ）フィルム、及びポリエステルフィルム等が挙げられる。 The support is not particularly limited, but examples include polyethylene terephthalate (PET) film and polyester film.
　磁性シートの厚さは、特に限定されないが、例えば、１０μｍ以上３００μｍ以下である。 Although the thickness of the magnetic sheet is not particularly limited, it is, for example, 10 μm or more and 300 μm or less.
　本実施形態に係る磁性シートは、加圧成形が容易であるため、狭小な隙間等への充填性が優れている。また磁性シートは、厚さが均一であり、薄膜形成が可能であるという利点もある。 The magnetic sheet according to the present embodiment is easy to be pressure-molded, so it is excellent in filling narrow gaps and the like. The magnetic sheet also has the advantage that it has a uniform thickness and can be formed into a thin film.
　（３）インダクタ部品
　本実施形態に係るインダクタ部品は、コイルと、成形体と、を備える（例えば、国際公開２０１９／０１７２３６号参照）。成形体は、コイルの少なくとも一部を内蔵する。成形体は、磁性樹脂組成物の硬化物で形成されている。 (3) Inductor component The inductor component according to this embodiment includes a coil and a molded body (see, for example, International Publication No. 2019/017236). The compact incorporates at least part of the coil. The molded body is formed of a cured product of a magnetic resin composition.
　このように、インダクタ部品は、上述の磁性樹脂組成物を用いて形成されているので、磁気損失を小さくすることができ、また直流重畳特性を向上させることができる。これにより、インダクタ部品の小型化を図ることもできる。また磁性樹脂組成物にカップリング剤が含有されていると、コイルと成形体との密着性を向上させることができる。 Thus, since the inductor component is formed using the magnetic resin composition described above, it is possible to reduce magnetic loss and improve DC superimposition characteristics. As a result, it is possible to reduce the size of the inductor component. Further, when the magnetic resin composition contains a coupling agent, the adhesion between the coil and the molded body can be improved.
　３．態様
　上記実施形態から明らかなように、本開示は、下記の態様を含む。 3. Aspects As apparent from the above embodiments, the present disclosure includes the following aspects.
　第１の態様は、磁性樹脂組成物であって、磁性粉末と、熱硬化性樹脂と、硬化剤と、を含有する。前記磁性粉末が、５０％体積平均粒子径（Ｄ５０）が４．０μｍ以下のカルボニル鉄粉を含む。 A first aspect is a magnetic resin composition containing a magnetic powder, a thermosetting resin, and a curing agent. The magnetic powder contains carbonyl iron powder having a 50% volume average particle size (D50) of 4.0 μm or less.
　この態様によれば、磁気損失を小さくすることができ、また直流重畳特性を向上させることができる。 According to this aspect, the magnetic loss can be reduced, and the DC superimposition characteristics can be improved.
　第２の態様は、第１の態様に基づく磁性樹脂組成物である。第２の態様では、前記磁性粉末の含有量が、前記磁性樹脂組成物の固形分合計１００質量％に対して、７８質量％以上９６質量％以下である。 The second aspect is the magnetic resin composition based on the first aspect. In a second aspect, the content of the magnetic powder is 78% by mass or more and 96% by mass or less with respect to the total solid content of 100% by mass of the magnetic resin composition.
　この態様によれば、磁性粉末の含有量が７８質量％以上であることで、比透磁率の低下を抑制し得る。磁性粉末の含有量が９６質量％以下であることで、成形性が向上し得る。 According to this aspect, since the content of the magnetic powder is 78% by mass or more, a decrease in relative magnetic permeability can be suppressed. When the magnetic powder content is 96% by mass or less, moldability can be improved.
　第３の態様は、第１又は第２の態様に基づく磁性樹脂組成物である。第３の態様では、前記カルボニル鉄粉の含有量が、前記磁性樹脂組成物の固形分合計１００質量部に対して、７０質量％以上９４質量％以下である。 A third aspect is a magnetic resin composition based on the first or second aspect. In a third aspect, the content of the carbonyl iron powder is 70% by mass or more and 94% by mass or less with respect to the total solid content of 100 parts by mass of the magnetic resin composition.
　この態様によれば、カルボニル鉄粉の含有量が７０質量％以上であることで、比透磁率の低下を抑制し得る。さらに直流重畳特性の低下も抑制し得る。カルボニル鉄粉の含有量が９４質量％以下であることで、成形性が向上し得る。 According to this aspect, since the content of the carbonyl iron powder is 70% by mass or more, a decrease in relative magnetic permeability can be suppressed. Furthermore, deterioration of DC superimposition characteristics can be suppressed. When the content of the carbonyl iron powder is 94% by mass or less, moldability can be improved.
　第４の態様は、第１～第３の態様のいずれか一つに基づく磁性樹脂組成物である。第４の態様では、前記磁性粉末が、フェライト粉を更に含む。 A fourth aspect is a magnetic resin composition based on any one of the first to third aspects. In a fourth aspect, the magnetic powder further contains ferrite powder.
　この態様によれば、磁性樹脂組成物の硬化物の損失係数（ｔａｎδ）をより小さくすることができる。 According to this aspect, the loss factor (tan δ) of the cured product of the magnetic resin composition can be made smaller.
　第５の態様は、第４の態様に基づく磁性樹脂組成物である。第５の態様では、前記フェライト粉の５０％体積平均粒子径（Ｄ５０）が０．０１μｍ以上１．０μｍ以下である。 A fifth aspect is a magnetic resin composition based on the fourth aspect. In a fifth aspect, the ferrite powder has a 50% volume average particle diameter (D50) of 0.01 μm or more and 1.0 μm or less.
　この態様によれば、フェライト粉の５０％体積平均粒子径（Ｄ５０）が０．０１μｍ以上であることで、表面積の増加が抑制され、成形性が向上し得る。フェライト粉の５０％体積平均粒子径（Ｄ５０）が１．０μｍ以下であることで、フェライト粉の粒子内の渦電流損失の増加が抑えられ、磁性樹脂組成物の硬化物の損失係数（ｔａｎδ）が増加しにくくなる。 According to this aspect, since the ferrite powder has a 50% volume average particle diameter (D50) of 0.01 μm or more, an increase in surface area can be suppressed and moldability can be improved. When the 50% volume average particle diameter (D50) of the ferrite powder is 1.0 μm or less, an increase in eddy current loss in the particles of the ferrite powder is suppressed, and the loss coefficient (tan δ) of the cured product of the magnetic resin composition becomes difficult to increase.
　第６の態様は、第４又は第５の態様に基づく磁性樹脂組成物である。第６の態様では、前記フェライト粉の含有量が、前記磁性樹脂組成物の固形分合計１００質量％に対して、１０質量％以上２０質量％以下である。 A sixth aspect is a magnetic resin composition based on the fourth or fifth aspect. In a sixth aspect, the content of the ferrite powder is 10% by mass or more and 20% by mass or less with respect to the total solid content of 100% by mass of the magnetic resin composition.
　この態様によれば、フェライト粉の含有量が１０質量％以上であることで、磁性樹脂組成物の硬化物の損失係数（ｔａｎδ）をより小さくすることができる。フェライト粉の含有量が２０質量％以下であることで、磁性樹脂組成物の硬化物の直流重畳特性の低下を抑制し得る。 According to this aspect, since the content of the ferrite powder is 10% by mass or more, the loss factor (tan δ) of the cured product of the magnetic resin composition can be further reduced. When the content of the ferrite powder is 20% by mass or less, it is possible to suppress deterioration of the DC superimposition characteristics of the cured product of the magnetic resin composition.
　第７の態様は、第１～第６の態様のいずれか一つに基づく磁性樹脂組成物である。第７の態様では、前記磁性樹脂組成物の硬化物の周波数１００ＭＨｚにおける比透磁率が８以上である。 A seventh aspect is a magnetic resin composition based on any one of the first to sixth aspects. In a seventh aspect, the cured product of the magnetic resin composition has a relative magnetic permeability of 8 or more at a frequency of 100 MHz.
　この態様によれば、磁気損失を小さくすることができ、また直流重畳特性を向上させることができる。 According to this aspect, the magnetic loss can be reduced, and the DC superimposition characteristics can be improved.
　第８の態様は、第１～第７の態様のいずれか一つに基づく磁性樹脂組成物である。第８の態様では、前記磁性樹脂組成物の硬化物の周波数１００ＭＨｚにおける損失係数が０．０４以下である。 An eighth aspect is a magnetic resin composition based on any one of the first to seventh aspects. In an eighth aspect, the loss factor at a frequency of 100 MHz of the cured product of the magnetic resin composition is 0.04 or less.
　この態様によれば、磁気損失を小さくすることができ、また直流重畳特性を向上させることができる。 According to this aspect, the magnetic loss can be reduced, and the DC superimposition characteristics can be improved.
　第９の態様は、第１～第８の態様のいずれか一つに基づく磁性樹脂組成物である。第９の態様では、前記磁性樹脂組成物の硬化物の周波数１００ｋＨｚにおける直流重畳許容電流値が１５Ａ以上である。 A ninth aspect is a magnetic resin composition based on any one of the first to eighth aspects. In a ninth aspect, the cured product of the magnetic resin composition has a DC superposition allowable current value of 15 A or more at a frequency of 100 kHz.
　この態様によれば、磁気損失を小さくすることができ、また直流重畳特性を向上させることができる。 According to this aspect, the magnetic loss can be reduced, and the DC superimposition characteristics can be improved.
　第１０の態様は、磁性シートであって、第１～第９の態様のいずれか一つに基づく磁性樹脂組成物を含む。 A tenth aspect is a magnetic sheet comprising a magnetic resin composition based on any one of the first to ninth aspects.
　この態様によれば、磁気損失を小さくすることができ、また直流重畳特性を向上させることができる。 According to this aspect, the magnetic loss can be reduced, and the DC superimposition characteristics can be improved.
　第１１の態様は、インダクタ部品であって、コイルと、成形体と、を備える。成形体は、コイルの少なくとも一部を内蔵する。成形体は、第１～第９の態様のいずれか一つに基づく磁性樹脂組成物の硬化物で形成されている。 An eleventh aspect is an inductor component comprising a coil and a molded body. The compact incorporates at least part of the coil. The molded body is formed of a cured magnetic resin composition according to any one of the first to ninth aspects.
　この態様によれば、磁気損失を小さくすることができ、また直流重畳特性を向上させることができる。 According to this aspect, the magnetic loss can be reduced, and the DC superimposition characteristics can be improved.
　以下、本開示を実施例によって具体的に説明する。ただし、本開示は、以下の実施例に限定されない。 The present disclosure will be specifically described below with reference to examples. However, the present disclosure is not limited to the following examples.
　１．試料
　（１）原料
　試料を作製するための磁性樹脂組成物の原料を以下に示す。 1. Samples (1) Raw Materials The raw materials of the magnetic resin composition for producing the samples are shown below.
　＜磁性粉末＞
　・カルボニル鉄粉Ａ（リン酸による絶縁処理済み、Ｄ５０：２．８μｍ、Ｄ９０：６．０μｍ、粒子形状：球状）
　・カルボニル鉄粉Ｂ（リン酸による絶縁処理済み、Ｄ５０：２．３μｍ、Ｄ９０：４．０μｍ、粒子形状：球状）
　・カルボニル鉄粉Ｃ（リン酸による絶縁処理済み、Ｄ５０：４．７μｍ、Ｄ９０：９．０μｍ、粒子形状：球状）
　・フェライト粉（Ｄ５０：０．２５μｍ、粒子形状：球状）
　・Ｆｅ基アモルファス合金粉（エプソンアトミックス株式会社製、商品名「ＡＷ２－０８／ＰＦ－３Ｋ」、Ｄ５０：３．３μｍ、Ｄ９０：５．５μｍ、粒子形状：球状）。 <Magnetic powder>
・Carbonyl iron powder A (insulated with phosphoric acid, D50: 2.8 μm, D90: 6.0 μm, particle shape: spherical)
・Carbonyl iron powder B (insulated with phosphoric acid, D50: 2.3 μm, D90: 4.0 μm, particle shape: spherical)
・Carbonyl iron powder C (insulated with phosphoric acid, D50: 4.7 μm, D90: 9.0 μm, particle shape: spherical)
・Ferrite powder (D50: 0.25 μm, particle shape: spherical)
- Fe-based amorphous alloy powder (manufactured by Epson Atmix Corporation, trade name "AW2-08/PF-3K", D50: 3.3 µm, D90: 5.5 µm, particle shape: spherical).
　＜熱硬化性樹脂＞
　・エポキシ樹脂１：ビスフェノールＦ型エポキシ樹脂（三菱化学株式会社製、商品名「ｊＥＲ　８０７」）
　・エポキシ樹脂２：多官能エポキシ樹脂（株式会社プリンテック製、商品名「ＴＥＣＨＭＯＲＥ　ＶＧ３１０１」）
　・フェノキシ樹脂：新日鉄住金化学株式会社製、商品名「ＹＰ－５０」、重量平均分子量Ｍｗ：６０，０００～８０，０００。 <Thermosetting resin>
- Epoxy resin 1: bisphenol F type epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name "jER 807")
・ Epoxy resin 2: Polyfunctional epoxy resin (manufactured by Printec Co., Ltd., trade name “TECHMORE VG3101”)
- Phenoxy resin: manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., trade name "YP-50", weight average molecular weight Mw: 60,000 to 80,000.
　＜硬化剤＞
　・硬化剤１：ジシアンジアミド
　・硬化剤２：イミダゾール系硬化促進剤（２－エチル－４－メチルイミダゾール、四国化成工業株式会社製、商品名「２Ｅ４ＭＺ」）。 <Curing agent>
• Curing agent 1: dicyandiamide • Curing agent 2: imidazole-based curing accelerator (2-ethyl-4-methylimidazole, manufactured by Shikoku Kasei Co., Ltd., trade name "2E4MZ").
　＜添加剤＞
　・カップリング剤：シランカップリング剤（エポキシシラン、モメンティブ社製、商品名「Ａ１８７１」）
　・分散剤：ポリオキシエチレン－ラウリルアミン（日油株式会社製、商品名「ナイミーンＬ－２０２」）
　＜溶剤＞
　・メチルエチルケトン
　・Ｎ，Ｎ－ジメチルホルムアミド
　（２）作製
　（２．１）磁性シート
　表１に示す配合量（質量％）で熱硬化性樹脂、硬化剤、添加剤、及び溶剤を配合することにより、ワニスを得た（インテグラルブレンド法）。次に表１に示す配合量（質量％）で磁性粉末を上記ワニスに配合することにより、スラリーを得た。次にこのスラリーにフィルタリングを行って不純物を除去することにより、液状の磁性樹脂組成物を得た。次に支持体として、あらかじめシリコーンによる離型処理が施されたＰＥＴフィルムを用意し、このＰＥＴフィルムに上記の液状の磁性樹脂組成物を塗布し、加熱乾燥させることにより、厚さ１００μｍの磁性シートを得た。この磁性シート内に残存する揮発分は０．２質量％未満であった。 <Additive>
Coupling agent: silane coupling agent (epoxysilane, manufactured by Momentive, trade name “A1871”)
・ Dispersant: Polyoxyethylene-laurylamine (manufactured by NOF Corporation, trade name “Nymeen L-202”)
<Solvent>
・Methyl ethyl ketone ・N,N-dimethylformamide (2) Production (2.1) Magnetic sheet A varnish was obtained (integral blend method). Next, a slurry was obtained by blending the magnetic powder into the above varnish in the blending amount (% by mass) shown in Table 1. Next, this slurry was filtered to remove impurities to obtain a liquid magnetic resin composition. Next, a PET film preliminarily subjected to mold release treatment with silicone was prepared as a support, and the liquid magnetic resin composition was applied to the PET film and dried by heating to form a magnetic sheet having a thickness of 100 μm. got The volatile content remaining in this magnetic sheet was less than 0.2% by mass.
　（２．２）試料
　上記磁性シートを複数重ね、真空下において１７５℃、１０ＭＰａの条件で２０分間加熱加圧して硬化させた後、１７５℃で９０分間加熱して後硬化させることにより、試料を作製した。試料は、外径が２０ｍｍ、内径が１６ｍｍ、厚みが３ｍｍ程度のリング状硬化物である。 (2.2) Sample A plurality of the above magnetic sheets were stacked and cured by heating and pressing for 20 minutes at 175°C and 10 MPa under vacuum, and then post-cured by heating at 175°C for 90 minutes to obtain a sample. made. The sample is a ring-shaped hardened material having an outer diameter of 20 mm, an inner diameter of 16 mm, and a thickness of about 3 mm.
　２．評価試験
　上記のようにして作製した試料を用いて以下の評価試験を行った。 2. Evaluation Test The following evaluation tests were performed using the samples produced as described above.
　（１）磁気特性
　上記試料の１００ＭＨｚでの複素透磁率（μ）をキーサイト・テクノロジー社製の型式「Ｅ４９９１Ｂインピーダンスアナライザ」により測定した。測定は、電流の周波数を１ＭＨｚ以上５００ＭＨｚ以下とし、常温で行った。測定して得られた、複素比透磁率（μｒ）の実数部（μｒ’）及び虚数部（μｒ”）から損失係数（ｔａｎδ）を算出した。 (1) Magnetic properties The complex magnetic permeability (μ) of the above sample at 100 MHz was measured with a model "E4991B impedance analyzer" manufactured by Keysight Technologies. The measurement was performed at room temperature with a current frequency of 1 MHz or more and 500 MHz or less. The loss factor (tan δ) was calculated from the real part (μ r ′ ) and the imaginary part (μ r ″) of the complex relative permeability (μ r ) obtained by the measurement.
　（２）直流重畳特性
　上記試料の１００ｋＨｚでの直流電流重畳インダクタンス測定を行った。この測定は、アクシスネット株式会社製の型式「ＤＣ２５Ａ電流重畳インダクタンス測定装置」を用いて行った。インダクタンスの初期値からの低下率が２０％となったときのバイアス電流値を直流重畳許容電流値として求めた。 (2) DC Superposition Characteristics A DC superimposition inductance was measured for the above sample at 100 kHz. This measurement was performed using a model "DC25A current superposition inductance measuring device" manufactured by Axisnet Co., Ltd. The bias current value when the rate of decrease from the initial value of the inductance reached 20% was determined as the allowable DC superposition current value.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002

Claims (11)

  1. 　磁性粉末と、熱硬化性樹脂と、硬化剤と、を含有し、
    　前記磁性粉末が、５０％体積平均粒子径（Ｄ５０）が４．０μｍ以下のカルボニル鉄粉を含む、
    　磁性樹脂組成物。     containing a magnetic powder, a thermosetting resin, and a curing agent,
    The magnetic powder contains carbonyl iron powder having a 50% volume average particle size (D50) of 4.0 μm or less,
    Magnetic resin composition.
  2. 　前記磁性粉末の含有量が、前記磁性樹脂組成物の固形分合計１００質量％に対して、７８質量％以上９６質量％以下である、
    　請求項１に記載の磁性樹脂組成物。     The content of the magnetic powder is 78% by mass or more and 96% by mass or less with respect to the total solid content of 100% by mass of the magnetic resin composition.
    The magnetic resin composition according to claim 1.
  3. 　前記カルボニル鉄粉の含有量が、前記磁性樹脂組成物の固形分合計１００質量％に対して、７０質量％以上９４質量％以下である、
    　請求項１に記載の磁性樹脂組成物。     The content of the carbonyl iron powder is 70% by mass or more and 94% by mass or less with respect to the total solid content of 100% by mass of the magnetic resin composition.
    The magnetic resin composition according to claim 1.
  4. 　前記磁性粉末が、フェライト粉を更に含む、
    　請求項１に記載の磁性樹脂組成物。     The magnetic powder further contains ferrite powder,
    The magnetic resin composition according to claim 1.
  5. 　前記フェライト粉の５０％体積平均粒子径（Ｄ５０）が０．０１μｍ以上１．０μｍ以下である、
    　請求項４に記載の磁性樹脂組成物。     The ferrite powder has a 50% volume average particle diameter (D50) of 0.01 μm or more and 1.0 μm or less.
    The magnetic resin composition according to claim 4.
  6. 　前記フェライト粉の含有量が、前記磁性樹脂組成物の固形分合計１００質量％に対して、５質量％以上３０質量％以下である、
    　請求項４に記載の磁性樹脂組成物。     The content of the ferrite powder is 5% by mass or more and 30% by mass or less with respect to the total solid content of 100% by mass of the magnetic resin composition.
    The magnetic resin composition according to claim 4.
  7. 　前記磁性樹脂組成物の硬化物の周波数１００ＭＨｚにおける比透磁率が８以上である、
    　請求項１に記載の磁性樹脂組成物。     A cured product of the magnetic resin composition has a relative magnetic permeability of 8 or more at a frequency of 100 MHz.
    The magnetic resin composition according to claim 1.
  8. 　前記磁性樹脂組成物の硬化物の周波数１００ＭＨｚにおける損失係数が０．０４以下である、
    　請求項１に記載の磁性樹脂組成物。     A cured product of the magnetic resin composition has a loss factor of 0.04 or less at a frequency of 100 MHz.
    The magnetic resin composition according to claim 1.
  9. 　前記磁性樹脂組成物の硬化物の周波数１００ｋＨｚにおける直流重畳許容電流値が１５Ａ以上である、
    　請求項１に記載の磁性樹脂組成物。     A cured product of the magnetic resin composition has a DC superposition allowable current value of 15 A or more at a frequency of 100 kHz.
    The magnetic resin composition according to claim 1.
  10. 　請求項１～９のいずれか１項に記載の磁性樹脂組成物を含む、
    　磁性シート。     comprising the magnetic resin composition according to any one of claims 1 to 9,
    magnetic sheet.
  11. 　コイルと、前記コイルの少なくとも一部を内蔵する成形体と、を備え、
    　前記成形体が、請求項１～９のいずれか１項に記載の磁性樹脂組成物の硬化物で形成されている、
    　インダクタ部品。     comprising a coil and a molded body containing at least part of the coil;
    The molded body is formed of a cured product of the magnetic resin composition according to any one of claims 1 to 9,
    inductor components.
PCT/JP2023/003168 2022-02-07 2023-02-01 Magnetic resin composition, magnetic sheet, and inductor component WO2023149454A1 (en)

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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1097913A (en) * 1996-09-24 1998-04-14 Tokin Corp Compound magnetic body, its manufacture and electromagnetic interference restraint
JP2005340368A (en) * 2004-05-25 2005-12-08 Aica Kogyo Co Ltd Ferrite-coated metal magnetic microparticle and manufacturing method thereof
JP2006196747A (en) * 2005-01-14 2006-07-27 Toda Kogyo Corp Carbonyl iron powder, electromagnetic wave interference restraining sheet comprising the same and manufacturing method thereof
JP2011135045A (en) * 2009-11-26 2011-07-07 Toray Ind Inc Method of manufacturing core-shell structured particle, paste composition using the same, and magnetic material composition using the same
JP2018170304A (en) * 2015-08-31 2018-11-01 アルプス電気株式会社 Dust core, method of producing the dust core, electrical/electronic component including the dust core, and electrical/electronic equipment including the electrical/electronic component mounted thereon
WO2019065923A1 (en) * 2017-09-29 2019-04-04 パウダーテック株式会社 Mn-zn ferrite particles, resin molded body, soft magnetic mixed powder, and magnetic core
JP2019102782A (en) * 2017-11-28 2019-06-24 住友ベークライト株式会社 Thermosetting resin composition, coil having magnetic core and/or outer package member, and method for manufacturing molded product
JP2020164899A (en) * 2019-03-28 2020-10-08 株式会社村田製作所 Composite magnetic material and inductor using the same

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1097913A (en) * 1996-09-24 1998-04-14 Tokin Corp Compound magnetic body, its manufacture and electromagnetic interference restraint
JP2005340368A (en) * 2004-05-25 2005-12-08 Aica Kogyo Co Ltd Ferrite-coated metal magnetic microparticle and manufacturing method thereof
JP2006196747A (en) * 2005-01-14 2006-07-27 Toda Kogyo Corp Carbonyl iron powder, electromagnetic wave interference restraining sheet comprising the same and manufacturing method thereof
JP2011135045A (en) * 2009-11-26 2011-07-07 Toray Ind Inc Method of manufacturing core-shell structured particle, paste composition using the same, and magnetic material composition using the same
JP2018170304A (en) * 2015-08-31 2018-11-01 アルプス電気株式会社 Dust core, method of producing the dust core, electrical/electronic component including the dust core, and electrical/electronic equipment including the electrical/electronic component mounted thereon
WO2019065923A1 (en) * 2017-09-29 2019-04-04 パウダーテック株式会社 Mn-zn ferrite particles, resin molded body, soft magnetic mixed powder, and magnetic core
JP2019102782A (en) * 2017-11-28 2019-06-24 住友ベークライト株式会社 Thermosetting resin composition, coil having magnetic core and/or outer package member, and method for manufacturing molded product
JP2020164899A (en) * 2019-03-28 2020-10-08 株式会社村田製作所 Composite magnetic material and inductor using the same

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