JP6290553B2 - Composite magnetic material - Google Patents

Description

  The present invention is used for the purpose of absorbing electromagnetic wave noise generated from an electronic device, etc., suppressing emission to the outside and entry from the outside, or preventing malfunction due to interference between components inside the electronic device. The composite magnetic body has the flexibility to follow the irregularities of circuit boards, electronic components, flexible printed wiring boards, etc., and also has flexibility and dimensional stability after a long-term heat-resistant reliability test at 150 ° C. The present invention relates to a composite magnetic body that can be used for reflow soldering, which is a basic process of surface mounting technology for electronic parts such as chip parts to a substrate.

In recent years, due to higher functionality of electronic devices, the operating frequency of electronic components has been increased, the intensity of emitted noise electromagnetic waves has increased, and a wider range of frequency components has been included. There is an increasing demand for further downsizing and weight reduction in these electronic devices. With this demand, electronic components used tend to be downsized, thinned, and mounted with high density. There is a problem that noise electromagnetic waves radiated from electronic components, printed wiring, or wiring between modules are likely to be generated as electronic devices are increased in frequency and mounted in high density.
In general, a composite magnetic material is used as a measure for suppressing noise electromagnetic waves in various electronic devices.
Examples of the composite magnetic material include binder resin such as chlorinated polyethylene rubber, acrylic rubber, and ethylene acrylic rubber, and powder of soft magnetic metal such as Sendust (Fe-Si-Al alloy), Permalloy (Fe-Ni alloy), Fe An electromagnetic wave suppression sheet in which atomized powder such as a Cr alloy is dispersed and formed into a sheet shape is known (for example, Patent Document 1).

  The ability of the composite magnetic body to suppress noise electromagnetic waves depends on its thickness, and various thicknesses of composite magnetic bodies are supplied depending on the application. For this reason, in the supply of the composite magnetic material, a composite magnetic material having an arbitrary thickness is manufactured and laminated according to the user's request in order to improve manufacturing efficiency. For example, as in the electromagnetic wave suppression sheet of the invention of Patent Document 1, a composite magnetic body using a thermoplastic resin is a solution (A stage) magnetic body in which soft magnetic metal powder is dispersed in a liquid resin composition. The magnetic coating material is applied to a substrate and dried to form a semi-cured sheet material in a semi-cured state (B stage), and the semi-cured sheet material is cured to a cured state (C stage). Is done. And the electromagnetic wave suppression sheet | seat is made into the electromagnetic wave suppression sheet | seat of desired thickness by overlapping as needed and heat-pressing.

  By the way, reflow soldering is a basic process for surface mounting technology of electronic parts such as chip parts to a substrate. Since general composite magnetic materials have poor heat resistance, they are softened by heating in a reflow furnace during reflow soldering and cannot retain their shape, or are in the form of local powdering, cracking, cracking, foaming, etc. Defects are likely to occur and cannot be used in high-temperature atmospheres such as reflow soldering. Therefore, the composite magnetic body has to be pasted after reflow soldering, which has been a process problem.

Conventionally, inventions that improve heat resistance and flexibility have been proposed.
For example, an electromagnetic wave suppression sheet in which flat soft magnetic powder is dispersed in a polyurethane resin is mounted on the upper surface of a semiconductor component, and heat such as a phenol resin, an epoxy resin, or an unsaturated polyester resin is covered so as to cover the electromagnetic wave suppression sheet. An invention has been proposed in which a curable resin is applied and fixed, and then passed through a solder reflow oven at 240 ° C. to cure the thermosetting resin, and the electromagnetic wave suppression sheet is sealed and fixed with the thermosetting resin (for example, Patent Document 2). According to the invention of Patent Document 2, it is described that the electromagnetic wave suppression sheet was not altered or malfunctioned even after the reflow process.
In addition, an electromagnetic wave suppression sheet in which soft magnetic metal powder is embedded in a thermosetting resin sheet of any one of an epoxy resin, an unsaturated polyester resin, a phenol resin, a melamine resin, and a urea resin has been proposed (for example, Patent Document 3). ).
Alternatively, an electromagnetic wave absorbing material composition comprising a compound having two or more carboxyl groups and / or acid anhydride groups in one molecule, a compound having two or more epoxy groups in one molecule, and soft magnetic powder Has been proposed (for example, Patent Document 4).

JP 2002-299112 A JP 11-307983 A JP 2002-111276 A JP 2005-252221 A

However, the inventions of Patent Documents 2 to 3 are not satisfactory in flexibility, although prevention of form defects (reflow resistance) is achieved in reflow soldering. The invention of Patent Document 4 is not satisfactory in reflow resistance, although improvement in flexibility is achieved. In addition, the composite magnetic body using the thermosetting resin is hard to adhere even if it is cured and stacked. For this reason, there is a problem in that it is necessary to produce a semi-cured sheet according to the thickness of the final product, which cannot be produced efficiently.
Accordingly, the present invention is directed to a composite magnetic body that can be efficiently manufactured and that can achieve both sufficient flexibility and reflow resistance.

  In general, when engineering plastics with high heat resistance increase the amount of soft magnetic metal powder in order to obtain an electromagnetic wave suppression function, the molded body becomes brittle or the flexibility is impaired, so that a satisfactory composite magnetic body can be obtained. Is difficult. On the other hand, some thermoplastic resins having low heat resistance can increase the filling amount of the soft magnetic metal powder, but the heat resistance of the resulting composite magnetic material is insufficient.

  As a result of intensive studies, the present inventors have blended an acrylic copolymer having a specific crosslinkable functional group, a phenol resin, and a compound containing two or more maleimide groups at a specific ratio, It is possible to achieve both sufficient flexibility and reflow resistance, and long-term heat-resistant reliability at 150 ° C without damaging the electromagnetic wave suppression function, and by stacking semi-cured sheet materials and applying heat treatment to laminate them The inventors have found that a composite magnetic body having an arbitrary thickness can be efficiently produced, and have reached the present invention.

That is, the composite magnetic material of the present invention comprises (A) component: an acrylic copolymer having an epoxy group, (B) component: phenol resin, and (C) component: maleimide group represented by the following formula. A soft magnetic metal powder is dispersed in a resin composition containing at least one compound (1) and compound (2) , wherein the epoxy value of the component (A) is 0.03 to 0.5 eq / kg. It is characterized by being.

  The component (A) is preferably an acrylic copolymer having a crosslinkable functional group having a glass transition temperature of −30 to 40 ° C., and more preferably a weight average molecular weight of 100,000 to 3,000,000. The crosslinkable functional group may be present in the polymer side chain or at the polymer chain end. Examples of the crosslinkable functional group include an epoxy group, an acryloyl group, a methacryloyl group, a hydroxyl group, a carboxyl group, Although an isocyanate group, an amino group, an amide group etc. are mentioned, an epoxy group is preferable.

  The component (B) is preferably a phenol resin containing a resol type alkylphenol, and more preferably a resol type phenol resin and a novolac type phenol resin are used in combination.

  According to the composite magnetic body of the present invention, it can be efficiently produced, and has sufficient flexibility, 150 ° C. long-term heat reliability and reflow resistance.

(Composite magnetic material)
The composite magnetic body of the present invention is one in which soft magnetic metal powder is dispersed in a resin composition, for example, formed into a sheet shape.

<Resin composition>
The resin composition of the present invention comprises (A) component: acrylic copolymer having a crosslinkable functional group, (B) component: phenol resin, and (C) component: maleimide group represented by the following formula. It contains the compound (1) and the compound (2) containing at least one.

  2-50 mass% is preferable, as for content of the resin composition in a composite magnetic body, 5-40 mass% is more preferable, and 5-20 mass% is further more preferable. If it is less than the lower limit, the function of the soft magnetic metal powder as a binder may be impaired, and the moldability of the composite magnetic body may be impaired. If the upper limit is exceeded, the electromagnetic wave control performance of the composite magnetic body may be impaired. May be insufficient.

<< (A) component: Acrylic copolymer having a crosslinkable functional group >>
The component (A) is an acrylic copolymer having a crosslinkable functional group, and the crosslinkable functional group may be present in the polymer side chain or at the polymer chain end. Examples of the crosslinkable functional group include an epoxy group, an acryloyl group, a methacryloyl group, a hydroxyl group, a carboxyl group, an isocyanate group, an amino group, an amide group, and the like. It is a copolymer containing ethylene ester, acrylonitrile, styrene or the like as the main component, mainly composed of an acid ester (the same applies hereinafter) and an alkyl acrylate (including a methacrylate ester, the same applies hereinafter). Examples of the alkyl acrylate ester include methyl acrylate (including methyl methacrylate, the same applies hereinafter), ethyl acrylate (including ethyl methacrylate, the same applies hereinafter), propyl acrylate, butyl acrylate (including butyl methacrylate), for example. ), Amyl acrylate, hexyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, undecyl acrylate, lauryl acrylate, and the like, and 2-hydroxyethyl acrylate, acrylic acid- Examples thereof include monomers having a hydroxyl group such as 2-hydroxypropyl and allyl alcohol. From these, one type or two or more types can be selected and used. Of these, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate are preferable in consideration of the flexibility of the composite magnetic material. Examples of the acrylic acid ester having an epoxy group include (meth) acrylic acid glycidyl ester. As content of an epoxy group, 0.03-0.5 eq / kg is preferable at an epoxy value, 0.05-0.4 eq / kg is more preferable, 0.07-0.3 eq / kg is further more preferable. When the epoxy value is less than the lower limit, it is difficult to improve the reflow resistance, and when it exceeds the upper limit, the flexibility tends to decrease.

(A) A component may be used individually by 1 type, or may use 2 or more types together.
Examples of the acrylic copolymer having a crosslinkable functional group include those synthesized by high-pressure radical polymerization and those synthesized by emulsion polymerization, but the generation of by-products is small and it is necessary to add an emulsifier or the like. Those synthesized by high-pressure radical polymerization with no cation are preferred. The method of high-pressure radical polymerization is not particularly limited, and a known method can be used.
The glass transition temperature of the acrylic copolymer having a crosslinkable functional group is preferably -30 to 40 ° C, more preferably -25 to 30 ° C, and further preferably -20 to 20 ° C. When the glass transition temperature is less than the lower limit, it is difficult to improve the reflow resistance, and when it exceeds the upper limit, the flexibility is lowered or it is difficult to laminate the semi-cured sheets. There is a possibility that the manufacturing workability of the composite magnetic material may be lowered.
The glass transition temperature is a value measured using a differential thermal analyzer (manufactured by Seiko Instruments Inc.) in accordance with JIS K7121.
The weight average molecular weight of the acrylic copolymer having a crosslinkable functional group is preferably 100,000 to 3,000,000, more preferably 300,000 to 2,000,000, and even more preferably 500,000 to 1,500,000. When the weight average molecular weight is within the above range, the thermal stability of the composite magnetic material becomes good and the reflow resistance is further improved. In addition, when the weight average molecular weight is within the above range, the workability and adhesiveness of the magnetic coating material are improved due to the improvement in solvent solubility and the decrease in melt viscosity. When the weight average molecular weight is less than the above lower limit, the heat resistance of the resin composition is lowered, and the reflow resistance may be lowered. In addition, the melt viscosity of the semi-cured sheet decreases, and the flow of the magnetic coating material increases in the film forming process described later, which may reduce the workability. If the weight average molecular weight exceeds the above upper limit, the solubility in a solvent is reduced in the coating preparation process described later, or the fluidity of the magnetic coating material is decreased in the film forming process described later, making film formation difficult. Or it may become difficult to laminate the semi-cured sheets, and the production efficiency of the composite magnetic body may be reduced.
The glass transition temperature is a value measured using gel permeation chromatography (manufactured by JASCO Corporation) in accordance with JIS K7252.
The content of the component (A) in the resin composition is preferably 0.1 to 10 in mass ratio represented by (A) component / [(B) component + (C) component]. It is more preferably 6 to 8, and further preferably 2.3 to 5. When the mass ratio is less than the above lower limit value, the flexibility of the semi-cured sheet material and the sheet material after the 150 ° C. heat resistance reliability test is likely to be impaired. It becomes difficult to improve the performance.

≪ (B) component: phenol resin≫
The component (B) is a phenol resin. (B) Although a well-known thing can be used as a component, the temperature at the time of making a semi-cured sheet material into a hardening state low temperature at the time of laminating | stacking a semi-cured sheet material, applying a hot press, and laminating | stacking. In addition, a resol-type alkylphenol resin is preferable because a sufficient adhesion between semi-cured sheets can be obtained, and it is more preferable to use a resol-type phenol resin and a novolac-type phenol resin in combination. preferable. The mass ratio represented by [resole type phenol resin / novolak type phenol resin] is preferably 1 to 20, and more preferably 2 to 10. When the mass ratio is less than the above lower limit value, the novolak type phenolic resin is inferior in curability by itself, so that the curability is lowered and it is difficult to improve the reflow resistance. The tackiness is expressed on the surface of the sheet-like sheet material and is cheaper, and the workability when superimposing the semi-cured sheet material is lowered. Examples of the phenolic resin containing a resol type alkylphenol include pt-butylphenol resol resin. Examples of the novolak type phenolic resin include pt-butylphenol novolak resin, phenol novolac resin, cresol novolac resin, and bisphenol novolac resin. And poly p-vinylphenol novolac resin.

≪ (C) component: a compound containing two or more maleimide groups≫
The component (C) is a compound containing two or more maleimide groups. The component (C) needs to use the compound (1) and the compound (2) shown in the above formula together, and the mass ratio represented by [compound (2) / compound (1)] is 1 to It is preferable that it is 15, and it is more preferable that it is 1.3-6.5. When the mass ratio is less than the above lower limit, the temperature when the semi-cured sheet material is laminated, subjected to hot pressing and laminated, and the temperature when the semi-cured sheet material is in a cured state becomes high temperature, If the energy efficiency is deteriorated and the value exceeds the upper limit, it is difficult to improve the reflow resistance.
The content of the component (B) in the resin composition is preferably such that the mass ratio represented by (B) component / [(B) component + (C) component] is 0.1 to 0.9. . If the mass ratio is less than the lower limit, the flexibility of the semi-cured sheet is likely to be impaired, and if it exceeds the upper limit, it is difficult to improve reflow resistance.

  The greater the total amount of components (A) to (C) that are essential components in the resin composition, the higher the effect of the present invention is, and 90 mass% or more is preferable, 95 mass% or more is preferable, and 100 More preferred is mass%.

≪Optional component in resin composition≫
The resin composition is a resin (arbitrary resin) other than the components (A) to (C), a curing agent (arbitrary curing agent) of the component (C), a curing accelerator, and the like as long as the effects of the present invention are not hindered. You may contain a component (henceforth the arbitrary component of a resin composition altogether).

Examples of the optional resin include natural rubber other than the component (A), a polyimide resin, and a polyamideimide resin. These optional resins can be used alone or in combination of two or more. The content of the optional resin in the resin composition is preferably 10% by mass or less, more preferably 5% by mass or less, and still more preferably not contained (1% by mass or less).
As an arbitrary component of a resin composition, the hardening | curing agent of (C) component and (D) component: diamine compound for adjustment of the curing temperature of a resin composition are mentioned. The component (D) is more preferably the compound (3) or the compound (4) represented by the following formula.

（式中、Ｒ^１は２価の芳香族基を表す）

(Wherein R ¹ represents a divalent aromatic group)

（式中、Ｒ^２はプロピレン基またはフェノキシメチレン基を表し、ｎは０ないし７の整数を示す）

(Wherein R ² represents a propylene group or a phenoxymethylene group, and n represents an integer of 0 to 7)

  The compound (3) is not particularly limited, and for example, 3,3′-diaminobiphenyl, 3,4′-diaminobiphenyl, 4,4′-diaminobiphenyl, 3,3′-diaminodiphenylmethane, 3,4 ′ -Diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 2,2- (3,3'-diaminodiphenyl) propane, 2,2- (3,4'-diaminodiphenyl) propane, 2,2- (4,4 '-Diaminodiphenyl) propane, 2,2- (3,3'-diaminodiphenyl) hexafluoropropane, 2,2- (3,4'-diaminodiphenyl) hexafluoropropane, 2,2- (4,4' -Diaminodiphenyl) hexafluoropropane, 3,3'-oxydianiline, 3,4'-oxydianiline, 4,4'-oxydianiline 3,3′-diaminodiphenylsulfide, 3,4′-diaminodiphenylsulfide, 4,4′-diaminodiphenylsulfide, 3,3′-diaminodiphenylsulfone, 3,4′-diaminodiphenylsulfone, 4,4 ′ -Diaminodiphenylsulfone, 1,3-bis [1- (3-aminophenyl) -1-methylethyl] benzene, 1,3-bis [1- (4-aminophenyl) -1-methylethyl] benzene, 1 , 4-bis [1- (3-aminophenyl) benzene, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (3-amino Phenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 3,3′-bis (3-aminophenoxy) diphenylate 3,3′-bis (4-aminophenoxy) diphenyl ether, 3,4′-bis (3-aminophenoxy) diphenyl ether, 3,4′-bis (4-aminophenoxy) diphenyl ether, 4,4′-bis ( 3-aminophenoxy) diphenyl ether, 4,4′-bis (4-aminophenoxy) diphenyl ether, 1,4-bis [1- (4-aminophenyl) -1-methylethyl-bis (3-aminophenoxy) biphenyl, 3,3′-bis (4-aminophenoxy) biphenyl, 3,4′-bis (3-aminophenoxy) biphenyl, 3,4′-bis (4-aminophenoxy) biphenyl, 4,4′-bis (3 -Aminophenoxy) biphenyl, 4,4'-bis (4-aminophenoxy) biphenyl, bis [4- (3-aminophen Enoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, 2,2-bis [3- (3-aminophenoxy) phenyl] propane, 2,2-bis [3- (4-amino) Phenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [3- (3-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis [3- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis [4- (3-aminophenoxy) phenyl] hexafluoro Propane, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 9,9-bis (3-aminopheny ) Fluorene, 9,9-bis (4-aminophenyl) fluorene, and the like.

Since the compound (4) is easily dissolved in a solvent and easy to handle, the weight average molecular weight is preferably 200 to 7,000.
The compound (4) is not particularly limited. For example, bis (3-aminopropyl) tetramethyldisiloxane, aminopropyl-terminated dimethylsiloxane tetramer, aminopropyl-terminated dimethylsiloxane octamer, bis (3- Aminophenoxymethyl) tetramethyldisiloxane and the like, and a mixture thereof may be used.
The content of the component (D) is preferably 0.01 to 2.0 molar equivalents of the amino group of the component (D) with respect to 1 molar equivalent of the maleimide group of the component (C). More preferably, it is 1.0 molar equivalent. (D) When content of a component is less than the said lower limit, the temperature in the case of making a semi-cured sheet material into a hardening state, and the temperature in the case of laminating | stacking a semi-cured sheet material and giving a hot press, and laminating | stacking it. It becomes difficult to adjust the temperature, and if it exceeds the upper limit, it is difficult to improve the reflow resistance.

Optional curing agents include diazabicyclooctane, methyl ethyl ketone peroxide, cyclohexane peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, methyl acetoacetate peroxide, acetylacetone peroxide, 1,1- Bis (t-butylperoxy) -3,3,5 trimethylhexane, 1,1-bis (t-butylperoxy) -cyclohexane, 2,2-bis (t-butylperoxy) octane, n-butyl- 4,4-bis (t-butylperoxy) valate, 2,2-bis (t-butylperoxy) butane, t-butyl hydroperoxide, cumene hydroperoxide, di-isopropylbenzene hydroperoxide, p- men Hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di-t-butyl peroxide, t-butylcumyl peroxide , Di-cumyl peroxide, α, α′-bis (t-butylperoxy-m-isopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5- Dimethyl-2,5-di (t-butylperoxy) hexyne, acetyl peroxide, isobutyl peroxide, octanoyl peroxide, decanoyl peroxide, benzoyl peroxide, lauroyl peroxide, 3,5,5-trimethylhexa Noyl peroxide, succinic acid peroxide, 2, 4-dichlorobenzoyl peroxide, m-toluoyl peroxide, di-isopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-n-propyl peroxydicarbonate, bis- (4-t-butyl) (Cyclohexyl) peroxydicarbonate, di-myristyl peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate, di-methoxyisopropyl peroxydicarbonate, di (3-methyl-3-methoxybutyl) peroxydi Carbonate, di-allyl peroxydicarbonate, t-butyl peroxyacetate, t-butyl peroxyisobutyrate, t-butyl peroxypivalate, t-butyl peroxyneodecanate, cumyl peroxyneodecane , T-butylperoxy-2-ethylhexanate, t-butylperoxy-3,5,5-trimethylhexanate, t-butylperoxylaurate, t-butylperoxybenzoate, di-t-butylper Oxyisophthalate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxymaleic acid, t-butylperoxyisopropylcarbonate, cumylperoxyoctate, t-hexylperoxyneo Organic peroxides such as decanate, t-hexylperoxypivalate, t-butylperoxyneohexanate, acetylcyclohexylsulfonyl peroxide, t-butylperoxyallyl carbonate, 1,2-dimethylimidazole, 1-methyl 2-ethylimidazole, 2 Methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-benzyl 2-phenylimidazole trimellitic acid salt, 1-benzyl-2-ethylimidazole, 1-benzyl-2-ethyl-5-methylimidazole, 2-ethylimidazole, 2-isopropylimidazole, 2-phenyl-4-benzyl Imidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-isopropylimidazole, 1-cyanoethyl- 2-phenylimidazole, 1-cyanoethyl-2-methylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6- [2'-methylimidazolyl- (1 ') ] -Ethyl-s-triazine, 2,4-diamino-6- [2'-ethyl-4-methylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- [2' -Undecylimidazolyl- (1 ')]-ethyl-s-triazine, 2-methylimidazolium isocyanuric acid adduct, 2-phenylimidazolium isocyanuric acid adduct, 2,4-diamino-6- [2' -Methylimidazolyl- (1 ')]-ethyl-s-triazine-isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole 2-phenyl-4-benzyl-5-hydroxymethylimidazole, 4,4′-methylene-bis- (2-ethyl-5-methylimidazole), 1-aminoethyl-2-methylimidazole, 1-cyanoethyl-2 -Phenyl-4,5-di (cyanoethoxymethyl) imidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazole-benzotriazole adduct, 1-aminoethyl-2-ethylimidazole, 1- (cyanoethylaminoethyl) -2-methylimidazole, N, N ′-[2-methylimidazolyl- (1) -ethyl] -adipoyldiamide, N, N′-bis- (2-methylimidazolyl-1) -Ethyl) urea, N- (2-methylimidazolyl-1-ethyl) urea, N, N '-[2-methyl Such as midazolyl- (1) -ethyl] dodecandioyl diamide, N, N ′-[2-methylimidazolyl- (1) -ethyl] eicosane oil amide, 1-benzyl-2-phenylimidazole / hydrochloride, etc. Examples include imidazoles and triphenylphosphine.
As for content of the arbitrary hardening | curing agent in a resin composition, 0.1-5 mass parts is preferable with respect to 100 mass parts of (A) component + (B) component.

<Soft magnetic metal powder>
Examples of soft magnetic metal powders include those conventionally used in composite magnetic materials, such as pure iron powder, Fe-Si alloy powder, Fe-Si-Al alloy powder, Fe-Ni alloy powder. Fe-Ni-Mo alloy powder, Fe-Ni-Mo-Cu alloy powder, Fe-Co alloy powder, Fe-Ni-Co alloy powder, Fe-Cr alloy powder, Fe-Cr-Si alloy Alloy powder, Fe—Ni—Cr alloy powder, Fe—Cr—Al alloy powder, etc. Among them, Fe—Cr alloy powder such as PC permalloy powder, Fe—Cr alloy powder, Fe—Cr alloy powder, Fe— Si-based alloy powder, Fe-Si-Al-based alloy powder, Fe-Co-based alloy powder, and Fe-Ni-based alloy powder are preferable. The soft magnetic metal powder is obtained by a wet method using a water atomization method, a gas atomization method, a pulverization method, or a chemical treatment.
As the soft magnetic metal powder, a powder obtained by treating the atomized powder with an attritor or a bead mill is preferable. By performing such treatment, the desired average particle diameter or flatness of the soft magnetic metal powder can be obtained.
The average particle size of the soft magnetic metal powder is preferably 30 to 200 μm. When the average particle size is less than the lower limit, the magnetic properties tend to be low, and when the average particle size exceeds the upper limit, it is difficult to maintain a desired shape.
The average particle diameter is a value determined by a laser diffraction / scattering particle diameter / particle size distribution measuring apparatus.

The flatness of the soft magnetic metal powder is preferably 30 to 200. When the flatness is less than the above lower limit value, the magnetic characteristics tend to be low, and when the flatness exceeds the upper limit value, it is difficult to maintain a desired shape.
Here, the value of “flatness” is represented by L _a / d _a . L _a is the average size of the soft magnetic metal powder, the soft magnetic metal powder and SEM observation from the surface direction to measure the major axis L and the short axis S, but sought the average value (L + S) / 2 is there. d _a is the thickness of the soft magnetic metal powder. The soft magnetic metal powder is embedded in the resin and polished, and the thickness direction of the powder is observed with an optical microscope, and the maximum thickness d _max and the minimum thickness d _min are , And the average value (d _max + d _min ) / 2 is obtained.

The content of the soft magnetic metal powder in the composite magnetic material can be determined in consideration of the content of the resin composition. The mass ratio represented by the soft magnetic metal powder / resin composition (hereinafter referred to as the metal / resin ratio). However, it is preferably 2-12. If the metal / resin ratio is less than the above lower limit, the electromagnetic wave suppression characteristics may be reduced, and if the metal / resin ratio exceeds the above upper limit, the adhesion of the soft magnetic metal powder by the resin composition is insufficient. There is a risk of becoming.
In particular, the mass ratio represented by the soft magnetic metal powder / [(A) component + (B) component + (C) component] is preferably 2 to 19.

<Arbitrary component in composite magnetic material>
The soft magnetic metal powder is a flame retardant, a flame retardant aid, a filler, a mold release agent, a surface treatment agent, a viscosity modifier, a plasticizer, an antibacterial agent, as long as the effect of the present invention is not impaired. You may contain arbitrary components, such as an antifungal agent, a leveling agent, an antifoamer, a coloring agent, a stabilizer, a coupling agent (henceforth, it is generally called the arbitrary component of a composite magnetic body).

Examples of the flame retardant include conventionally known flame retardants, and include aluminum hydroxide and / or magnesium hydroxide from the viewpoint of halogen-free and further improvement in reflow resistance.
The content of the flame retardant in the composite magnetic body is preferably 40 to 150 parts by mass with respect to 100 parts by mass of the resin composition. If it is less than the lower limit, sufficient flame retardancy may not be obtained, and if it exceeds the upper limit, the adhesion of the soft magnetic metal powder may be insufficient.

Examples of the flame retardant aid include conventionally known flame retardant aids. From the viewpoint of halogen-free, for example, at least one selected from red phosphorus, ammonium polyphosphate, melamine polyphosphate, and phosphate ester is preferable.
The content of the flame retardant aid in the composite magnetic material is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the resin composition. If it is less than the lower limit, sufficient flame retardancy may not be obtained, and if it exceeds the upper limit, heat resistance may be reduced.
The composite magnetic body is composed of a flame retardant composed of aluminum hydroxide and / or magnesium hydroxide having an average particle size of 0.1 to 3 μm, and at least one selected from red phosphorus, ammonium polyphosphate, melamine polyphosphate, and phosphate ester. It is preferable to contain a flame retardant aid.
The composite magnetic body has a mass ratio represented by the flame retardant / [(A) component + (B) component + (C) component] of 0.4 to 1.5, and the flame retardant aid / [ The mass ratio represented by (A) component + (B) component + (C) component] is preferably 0.01 to 0.1.

(Production method)
The method for producing a composite magnetic body of the present invention includes, for example, a step of obtaining a magnetic coating material in which components (A) to (C) and a soft magnetic metal powder are dispersed in a solvent (paint preparation step), and a magnetic coating material. What has a process (film formation process) which apply | coats and dries to desired thickness and obtains a semi-cured sheet material, and a process (curing process) which heats and cures a semi-cured sheet material is mentioned.

  As a method for preparing the magnetic coating material, a conventionally known method can be used. For example, the components (A) to (C) and optional components of the resin composition are added to a solvent, and stirred. A method of adding a soft magnetic metal powder and, if necessary, an optional component of the composite magnetic material to the resin solution and stirring the resin solution may be mentioned. In addition, for example, the components (A) to (C) and the optional component of the resin composition or the optional component of the composite magnetic substance are added to the solvent, if necessary, and stirred, and then the soft magnetic metal powder is added. And a method of stirring.

Solvents used in the coating preparation process include, for example, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and isophorone, ester solvents such as ethyl acetate and butyl acetate, aromatic solvents such as toluene and xylene, cellosolve acetate, methyl cellosolve acetate And an aprotic polar solvent such as dimethylformamide, an ether solvent such as tetrahydrofuran and diethylene glycol dimethyl ether, an alcohol such as isopropyl alcohol and n-butyl alcohol, and the like.
The content of the solvent in the magnetic coating material is appropriately determined in consideration of the viscosity required for the magnetic coating material.

In the film forming step, a conventionally known film forming method can be used, and examples thereof include a method in which a magnetic coating material is applied to a peelable film at an arbitrary thickness and dried.
Examples of the coating method include a method using a bar coater, a comma coater, a die coater, or the like.
Although the thickness of a semi-hardened sheet material is not specifically limited, For example, 50-500 micrometers is preferable and 50-100 micrometers is more preferable.

Examples of the peelable film include a polypropylene film, a fluororesin film, a polyethylene film, a polyethylene terephthalate (PET) film, paper, and those obtained by subjecting these to a release treatment with a silicone resin (release treatment film).
Although the thickness of a peelable film is not specifically limited, 1-200 micrometers is preferable and 10-50 micrometers is more preferable.
The peelable film preferably has a peel strength of 0.01 to 7.0 g / cm. If the above lower limit is exceeded, the composite magnetic body and the peelable film are not easily peeled off, and the composite magnetic body is easy to handle. If less than the above upper limit, the composite magnetic body is peeled from the peelable film. When this is done, defects and the like do not occur, and manufacturing efficiency increases.

The drying method is not particularly limited as long as it evaporates the solvent in the magnetic coating material applied to the peelable film and brings the resin composition into a semi-cured state. For example, the magnetic material applied to the peelable film The method of heating a coating material at arbitrary temperatures is mentioned.
The heating temperature in the film forming step can be determined in consideration of the component (A), the component (C), the type of solvent, and the like.
The heating time in the film forming process can be determined in consideration of the types of the component (A), the component (C) and the solvent.
The semi-cured sheet material may be immediately subjected to a curing process after drying, or may be stored as a work in progress.

The curing step is a step of heating the semi-cured sheet material to cure the resin composition to obtain a composite magnetic body.
A conventionally known curing method can be used as the curing method, and examples thereof include a method of heating at an arbitrary temperature and a method of heating at an arbitrary temperature while pressing at an arbitrary pressure.
The heating temperature in the curing step can be determined in consideration of the types of the component (A) and the component (C).
When pressing in the curing step, the pressure is not particularly limited, but is, for example, 5 to 30 MPa.
The composite magnetic body in which the resin composition is in a cured state is cut into a desired dimension and commercialized.

  As needed, you may laminate | stack a new peelable film on the exposed surface of the semi-hardened sheet material or composite magnetic body on a peelable film before or after a hardening process. Thus, by providing the peelable film on both surfaces of the composite magnetic body, it is possible to prevent adhesion of foreign matters.

The composite magnetic body may be provided with a heat resistant adhesive layer on one side or both sides. By providing the heat-resistant adhesive layer, the composite magnetic body can be easily fixed to the object to be pasted.
Examples of the pressure-sensitive adhesive constituting the heat-resistant pressure-sensitive adhesive layer include conventionally known pressure-sensitive adhesives such as a methylphenyl silicone pressure-sensitive adhesive, an addition reaction type silicone pressure-sensitive adhesive, and a peroxide sulfide type silicone pressure-sensitive adhesive.

As described above, according to the present invention, since the component (A) and the component (B) are contained at a specific ratio, both flexibility and reflow resistance can be achieved.
In addition, since the component (C) is used as a curing agent, it is possible to efficiently produce a composite magnetic body product having a desired thickness by stacking semi-cured sheets as necessary and performing hot pressing or the like. .

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited by these Examples.
Example 1
The molten Fe—Si—Al alloy was gas atomized to obtain a spherical powder having an average particle size of 100 μm. This was put into an attritor and stirred to obtain a soft magnetic metal powder having an average particle size of 50 μm, a thickness of 1 μm and a flatness of 50.
Component (A): An acrylic copolymer having an epoxy group having an epoxy value of 0.21 eq / kg, a glass transition temperature of 12 ° C., and a weight average molecular weight of 850,000 (trade name: “Taisan Resin SG-P3 (solid content: 15%) ”, Manufactured by Nagase ChemteX Corporation), 20 parts by mass, (B) component: pt-butylphenol type resol phenol resin (trade name:“ CKM-1282 ”, manufactured by Showa Polymer Co., Ltd.), 1.67 parts by mass, and 0.67 parts by mass of pt-butylphenol and Bis-A copolymer type novolak phenol resin (trade name: “CKM-2400”: Showa Polymer Co., Ltd.), component (C): represented by the above-mentioned formula Compound (1) 1.00 parts by mass, and commercially available compound (2) 1.67 parts by mass, flame retardant: aluminum hydroxide 25 parts by mass, flame retardant aid: red phosphorus 1.5 mass Part It added and stirred to Rahidorofuran 10 parts by weight, further the soft magnetic metal powder 200 parts by weight was added, and stirred to obtain a magnetic paint.

  The obtained magnetic coating material was applied to the release-treated surface of the release-treated film (PET) so that the thickness after drying was 130 μm, and heated at 150 ° C. for 2 minutes in a hot air circulating dryer, A semi-cured sheet was obtained. The resulting semi-cured sheet was evaluated for laminate properties. Further, in order to improve the orientation of the soft magnetic metal powder, the semi-cured sheet was pressed with a hot press machine at 180 ° C. for 60 minutes at 20 MPa to obtain a composite magnetic body having a thickness of 99 μm. About the obtained composite magnetic body, magnetic permeability, reflow resistance, 150 degreeC long-term heat-resistant reliability, a softness | flexibility, and internal stress relaxation property were evaluated. The evaluation results are shown in Table 1.

(Example 2)
A semi-cured sheet and a composite magnetic body having a thickness of 100 μm were obtained in the same manner as in Example 1 except that a soft magnetic metal powder having an average particle size of 30 μm, a thickness of 1 μm, and a flatness of 30 was used. Magnetic permeability, reflow resistance, 150 ° C. long-term heat reliability, flexibility, and internal stress relaxation were evaluated. The evaluation results are shown in Table 1.

(Example 3)
Except for using a soft magnetic metal powder having an average particle size of 50 μm, a thickness of 2 μm, and a flatness of 25, a semi-cured sheet and a composite magnetic material having a thickness of 100 μm were obtained in the same manner as in Example 1, Magnetic permeability, reflow resistance, 150 ° C. long-term heat-resistant reliability, flexibility, stackability, and internal stress relaxation were evaluated. The evaluation results are shown in Table 1.

Example 4
A semi-cured sheet and a composite magnetic material having a thickness of 98 μm were prepared in the same manner as in Example 1 except that a soft magnetic metal powder of an average particle size of 49 μm, a thickness of 1 μm, and a flatness of 30 Fe—Si alloy was used. The laminate was evaluated for laminateability, magnetic permeability, reflow resistance, 150 ° C. long-term heat reliability, flexibility, and internal stress relaxation. The evaluation results are shown in Table 1.

(Example 5)
A semi-cured sheet and a composite magnetic body having a thickness of 98 μm are the same as in Example 1 except that a soft magnetic metal powder of an Fe—Ni alloy having an average particle diameter of 52 μm, a thickness of 1 μm, and a flatness of 52 is used. The laminate was evaluated for laminateability, magnetic permeability, reflow resistance, 150 ° C. long-term heat reliability, flexibility, and internal stress relaxation. The evaluation results are shown in Table 1.

(Example 6)
A semi-cured sheet and a composite magnetic body having a thickness of 100 μm were obtained in the same manner as in Example 1 except that the soft magnetic metal powder was changed to 125 parts by mass, and the lamination property, magnetic permeability, reflow resistance, 150 ° C. long-term Heat resistance, flexibility, and internal stress relaxation were evaluated. The evaluation results are shown in Table 2.

(Example 7)
(A) Except for the component having an epoxy value of 0.07 eq / kg, a glass transition temperature of −14 ° C., an acrylic copolymer having an epoxy group with a weight average molecular weight of 700,000 being 20 parts by mass, and tetrahydrofuran being 100 parts by mass, In the same manner as in Example 1, a semi-cured sheet and a composite magnetic body having a thickness of 103 μm were obtained and evaluated for lamination property, magnetic permeability, reflow resistance, 150 ° C. long-term heat reliability, flexibility, and internal stress relaxation. did. The evaluation results are shown in Table 2.

(Example 8)
Component (A) is an acrylic copolymer having an epoxy group having an epoxy value of 0.21 eq / kg, a glass transition temperature of 12 ° C., and a weight average molecular weight of 1,200,000 (trade name: “Taisan Resin (solid content 15%)”) 20 A semi-cured sheet and a composite magnetic body having a thickness of 100 μm were obtained in the same manner as in Example 1 except for changing to parts by mass, and lamination properties, magnetic permeability, reflow resistance, 150 ° C. long-term heat reliability, flexibility The internal stress relaxation property was evaluated. The evaluation results are shown in Table 2.

Example 9
(B) Semi-hardened sheet material and thickness were the same as in Example 1 except that the component was changed to 2.34 parts by mass of a pt-butylphenol type resol phenol resin (CKM-1282: manufactured by Showa Polymer Co., Ltd.). A composite magnetic body having a thickness of 100 μm was obtained, and evaluated for lamination property, magnetic permeability, reflow resistance, 150 ° C. long-term heat reliability, flexibility, and internal stress relaxation. The evaluation results are shown in Table 2.

(Example 10)
Component (B) is a pt-butylphenol type resol phenol resin (trade name: “CKM-1282”, manufactured by Showa Kogyo Co., Ltd.) 1.34 parts by mass of pt-butylphenol and Bis-A copolymer type novolak phenol A semi-cured sheet and a composite magnetic body with a thickness of 100 μm were obtained in the same manner as in Example 1 except that the resin (CKM-2400: manufactured by Showa Polymer Co., Ltd.) was 1.00 parts by mass. Magnetic properties, reflow resistance, 150 ° C. long-term heat reliability, flexibility, and internal stress relaxation were evaluated. The evaluation results are shown in Table 2.

(Example 11)
The component (C) was the same as in Example 1, except that 0.50 parts by mass of the compound (1) represented by the above formula and 2.17 parts by mass of the compound (2) represented by the above formula were commercially available. Then, a semi-cured sheet and a composite magnetic body having a thickness of 100 μm were obtained and evaluated for lamination property, magnetic permeability, reflow resistance, 150 ° C. long-term heat reliability, flexibility, and internal stress relaxation. The evaluation results are shown in Table 3.

(Example 12)
Semi-cured in the same manner as in Example 1 except that 0.08 parts by mass of 1,3-bis (3-aminopropyl) -1,1,3,3-tetramethyldisiloxane was added as component (D). Sheet material and a composite magnetic material having a thickness of 100 μm were obtained and evaluated for laminateability, magnetic permeability, reflow resistance, 150 ° C. long-term heat reliability, flexibility, and internal stress relaxation. The evaluation results are shown in Table 3.

(Example 13)
(D) Except having added 0.08 mass part of 1, 4- diaminobenzene as a component, it carried out similarly to Example 1, and obtained the semi-hardened sheet material and the 100-micrometer-thick composite magnetic body, laminating property, transparency Magnetic properties, reflow resistance, 150 ° C. long-term heat reliability, flexibility, and internal stress relaxation were evaluated. The evaluation results are shown in Table 3.

(Comparative Example 1)
A semi-cured sheet and a composite magnetic body having a thickness of 100 μm were used in the same manner as in Example 1 except that 25 parts by mass of chlorinated polyethylene (chlorinated PE) was used instead of the components (A) to (C). The laminate was evaluated for laminateability, magnetic permeability, reflow resistance, 150 ° C. long-term heat reliability, flexibility, and internal stress relaxation. These evaluation results are shown in Table 4.

(Comparative Example 2)
(A) The same procedure as in Example 1 was used, except that the component was not used, flame retardant: 5 parts by weight of aluminum hydroxide, flame retardant aid: 0.9 parts by weight of red phosphorus, and 40 parts by weight of soft magnetic metal powder. Then, a semi-cured sheet and a composite magnetic body having a thickness of 100 μm were obtained and evaluated for lamination property, magnetic permeability, reflow resistance, 150 ° C. long-term heat reliability, flexibility, and internal stress relaxation. These evaluation results are shown in Table 4.

(Comparative Example 3)
A semi-cured sheet and a composite magnetic material having a thickness of 100 μm were obtained in the same manner as in Example 1 except that the component (B) was not used and the component (C) was replaced by 5 parts by mass, and the laminate property and magnetic permeability were obtained. Evaluation was made on reflow resistance, long-term heat resistance at 150 ° C., flexibility, and internal stress relaxation. These evaluation results are shown in Table 4.

(Comparative Example 4)
A semi-cured sheet and a composite magnetic body having a thickness of 100 μm were obtained in the same manner as in Example 1 except that the component (B) was not used and the component (B) was changed to 5 parts by mass, and the lamination property and magnetic permeability were obtained. Evaluation was made on reflow resistance, long-term heat resistance at 150 ° C., flexibility, and internal stress relaxation. These evaluation results are shown in Table 4.

(Evaluation method)
<Permeability>
For the composite magnetic body of each example, a real term and an imaginary term are obtained, and those having a real term of 80 or more and an imaginary term of 20 or more are regarded as “good”, and those having a real number less than 80 or less than the imaginary term 20 are rejected. ".

≪Real term of permeability≫
The composite magnetic material of each example was punched into a ring shape having an outer diameter of 7 mm and an inner diameter of 3 mm, and this was wound with 12 turns to obtain a test piece. About this test piece, it calculated with the impedance in 1 MHz using the impedance measuring instrument "Precision Impedance Analyzer HP4294A" by Agilent Technologies.

≪Imaginary term of permeability≫
For the test piece prepared in the above << real number term of magnetic permeability >>, the loss term is measured in the range of 1 MHz to 10 GHz using an S parameter measuring device “Network Analyzer E5071C” manufactured by Agilent Technologies, and the maximum value is an imaginary term. It was.

≪Reflow resistance≫
The composite magnetic material of each example was used as a 50 mm long × 50 mm wide test piece. The test piece was subjected to a solder reflow test (twice at 260 ° C. for 10 seconds × 2 times) in accordance with JIS C-5012 “Test method for printed wiring board” 10.4.1 “Solder float method”. The test piece after the solder reflow test was observed with the naked eye and evaluated according to the following evaluation criteria.

[Evaluation criteria]
A: No change in appearance is observed after the reflow test.
○: Almost no change in appearance was observed after the reflow test.
Δ: Strain is observed after the reflow test, but no swelling, powdering, cracking or cracking is observed.
X: Swelling, powdering, cracking or cracking is observed after the reflow test.

≪150 ℃ long-term heat resistance reliability≫
The composite magnetic body of each example was used as a 100 mm long × 100 mm wide test piece. About this test piece, the 150 degreeC long-term heat-resistant reliability test (2,000 hours at 150 degreeC) was given. About the test piece before and behind a 150 degreeC long-term heat-resistant reliability test, the thickness change was measured using the micrometer and evaluated according to the following evaluation criteria.

[Evaluation criteria]
A: The thickness change is within 5%.
○: The thickness change is 6 to 10%.
Δ: Thickness change is 11 to 15%.
X: Thickness change exceeds 15%.

≪Flexibility≫
The composite magnetic material of each example was used as a 50 mm long × 50 mm wide test piece. About this test piece, in accordance with JIS C-5012 “Printed Wiring Board Test Method” 10.4.1 “Solder Float Method”, solder reflow test (twice at 260 ° C. for 10 seconds × 2 times) and 150 ° C. long-term heat resistance A reliability test (2,000 hours at 150 ° C.) was performed. For test pieces before and after solder reflow test and before and after 150 ° C long-term heat reliability test, manufactured by Toyo Seiki Seisakusyo Co., Ltd., MIT fatigue resistance tester, model number: DA, test conditions with bending speed of 175 times / minute, bending angle It was bent at 135 ° and a load of 4.9 N. The test piece after bending was observed with the naked eye and evaluated according to the following evaluation criteria.

[Evaluation criteria]
A: No whitening, cracks or cracks are observed at the bent part.
○: Cracks and cracks are not observed in the bent part, but whitening is observed.
Δ: Cracks or cracks are observed in the bent portion.
X: It cut | disconnected by the bending part.

≪Internal stress relaxation≫
The composite magnetic material of each example was bonded to a commercially available glass epoxy-printed wiring board at 150 ° C., and then pressed at 150 ° C. and 20 MPa with a hot press machine to obtain a test piece. This sample piece was subjected to a thermal cycle test of 10 cycles, with 150 ° C. × 2 hours and −40 ° C. × 2 hours as one cycle. The test piece after the heat cycle test was observed with the naked eye and evaluated according to the following evaluation criteria.

[Evaluation criteria]
A: No change in appearance is observed after the thermal cycle test.
○: Almost no change in appearance was observed after the thermal cycle test.
Δ: Strain is observed after the thermal cycle test, but swelling, powdering, cracking and cracking are not observed.
X: Swelling, cracking or cracking is observed after the thermal cycle test.

≪Laminating properties≫
Three semi-cured sheets of each example were stacked and subjected to hot pressing at 150 ° C. and 20 MPa for 10 seconds. After the hot pressing, the composite magnetic body was visually observed, and the adhesion state was evaluated according to the following evaluation criteria.

[Evaluation criteria]
(Double-circle): The boundary of each layer is not recognized but it has become one composite magnetic body as a whole.
○: The boundary of each layer is recognized, but each layer is in close contact and does not peel off.
(Triangle | delta): The boundary of each layer is recognized and each layer can be peeled with fingers.
X: Each layer is separated and separated (efficient production is impossible).

As shown in Table 1, each of Examples 1 to 13 to which the present invention was applied had a magnetic permeability of “◯”, and could sufficiently absorb electromagnetic noise generated from an electronic device or the like. In addition, in Examples 1 to 13, the internal stress relaxation property was “◎”, and quality deterioration hardly occurred even in long-term use. Further, in Examples 1 to 13, the reflow resistance, flexibility, lamination property, and 150 ° C. long-term heat reliability were “」 ”.
Comparative Example 1 in which the resin composition is chlorinated polyethylene and Comparative Example 4 in which the component (C) is not used are “x” in reflow resistance, and after solder reflow, deformation is significant and flexibility can be evaluated. There wasn't.
In Comparative Example 2 in which the component (A) was not used, the flexibility, the laminate property, and the internal stress relaxation property were “x”, and it was difficult to form a composite magnetic body into a sheet and laminate.
In Comparative Example 3 in which the component (B) was not used, the lamination property was “x”, and a composite magnetic body could not be produced with high production efficiency.
From these results, it was found that by applying the present invention, it is possible to obtain a composite magnetic body that has sufficient flexibility and does not cause a defective shape in reflow soldering and can be manufactured with high manufacturing efficiency.

Claims (16)

(A) component: an acrylic copolymer having an epoxy group, (B) component: a phenol resin, and (C) component: a compound (1) and a compound containing two or more maleimide groups represented by the following formula (2) and
A composite magnetic body, wherein a soft magnetic metal powder is dispersed in a resin composition having an epoxy value of 0.03 to 0.5 eq / kg of the component (A).

  The soft magnetic metal powder is a flaky powder having an average particle diameter of 30 to 200 µm and a flatness of 30 to 200 obtained by flattening an atomized powder made of a soft magnetic metal or alloy. Composite magnetic material.   The soft magnetic powder is Fe-Si based alloy powder, Fe-Si-Al based alloy powder, Fe-Ni based alloy powder, Fe-Ni-Mo based alloy powder, Fe-Ni-Mo-Cu based alloy powder, Fe The composite magnetic body according to claim 1, wherein the composite magnetic body is at least one selected from —Cr-based alloy powder.   2. The composite magnetic body according to claim 1, wherein a mass ratio represented by the soft magnetic metal powder / [(A) component + (B) component + (C) component] is 2-19.   The composite magnetic body according to claim 1, wherein the component (A) is an acrylic copolymer having a glass transition temperature of −30 to 40 ° C.   The composite magnetic body according to claim 1, wherein the component (A) is an acrylic copolymer having a weight average molecular weight of 100,000 to 3,000,000.   The composite magnetic body according to claim 1, wherein the component (B) is a phenol resin containing a resol-type alkylphenol.   The composite magnetic body according to claim 1, wherein the component (B) uses a resol type phenol resin and a novolac type phenol resin in combination.   2. The composite magnetic body according to claim 1, wherein the component (C) has a mass ratio of 1 to 15 represented by compound (2) / compound (1).   The mass ratio represented by (A) component / [(B) component + (C) component] is 0.1 to 10, and (B) component / [(B) component + (C) component]. 2. The composite magnetic body according to claim 1, wherein a mass ratio represented by the formula is 0.1 to 0.9.   2. The composite magnetic body according to claim 1, further comprising (D) component: diamine compound in addition to the (A) component, (B) component, and (C) component. The composite magnetic body according to claim 11 , wherein the component (D) is a compound (3) represented by the following formula.

(Wherein R1 represents a divalent aromatic group) The composite magnetic body according to claim 11 , wherein the component (D) is a compound (4) represented by the following formula having a weight average molecular weight of 200 to 7,000.

(Wherein R2 represents a propylene group or a phenoxymethylene group, and n represents an integer of 0 to 7)   A flame retardant aid comprising a flame retardant comprising aluminum hydroxide and / or magnesium hydroxide having an average particle size of 0.1 to 3 μm, and at least one selected from red phosphorus, ammonium polyphosphate, melamine polyphosphate, and phosphate ester The composite magnetic body according to claim 1, comprising: The mass ratio represented by the flame retardant / [(A) component + (B) component + (C) component] is 0.4 to 1.5, and the flame retardant aid / [(A) component + The composite magnetic body according to claim 14 , wherein a mass ratio represented by (B) component + (C) component] is 0.01 to 0.1.   2. The composite magnetic body according to claim 1, wherein a heat resistant adhesive layer is laminated on one side or both sides of the composite magnetic body.