JP2021141144A - Magnetic resin composition and molded product - Google Patents

Abstract

To provide a magnetic resin composition with high chemical resistance capable of obtaining a molded product whose magnetic properties do not easily deteriorate even when exposed to chemicals.SOLUTION: The magnetic resin composition includes a filler and a resin material. The filler contains a magnetic filler containing iron-nickel alloy filler. The nickel content is more than 39 mass% with respect to the total mass of the iron-nickel alloy filler.SELECTED DRAWING: None

Description

The present disclosure relates generally to magnetic resin compositions and molded articles, and more specifically to magnetic resin compositions and molded articles comprising fillers and resin materials.

Patent Document 1 discloses a composite magnetic encapsulating material. This composite magnetic encapsulation material includes a resin material and a filler. The filler is blended with the resin material and has a blending ratio of 30 to 85% by volume. Further, the filler contains a magnetic filler. In this magnetic filler, Fe contains 32 to 39% by weight of a metal material containing Ni as a main component. As a result, the composite magnetic encapsulant material has a coefficient of thermal expansion of 15 ppm / ° C. or less.

JP-A-2017-188646

However, the present inventors have found that the composite magnetic encapsulant material has a problem of low chemical resistance. That is, if the composite magnetic encapsulant material is exposed to chemicals during some processing, its original magnetic properties may deteriorate.

An object of the present disclosure is to provide a magnetic resin composition and a molded product capable of obtaining a molded product having high chemical resistance and hardly deteriorating magnetic properties even when exposed to chemicals.

The magnetic resin composition according to one aspect of the present disclosure includes a filler and a resin material. The filler contains a magnetic filler containing an iron-nickel alloy filler. The nickel content is more than 39% by mass with respect to the total mass of the iron-nickel alloy filler.

The molded product according to one aspect of the present disclosure is formed of the magnetic resin composition.

According to the present disclosure, it is possible to obtain a molded product having high chemical resistance and whose magnetic properties do not easily deteriorate even when exposed to chemicals.

1. 1. Outline The magnetic resin composition according to the present embodiment includes a filler and a resin material. The filler contains a magnetic filler. As a result, the molded product of the magnetic resin composition has magnetic properties. Further, the magnetic filler includes an iron-nickel alloy filler. The nickel content is more than 39% by mass with respect to the total mass of the iron-nickel alloy filler. As described above, since the nickel content is higher than that of the conventional iron-nickel alloy filler, the chemical resistance of the molded product is increased. Therefore, even if the molded product is exposed to the chemical, the molded product can maintain the magnetic properties before being exposed to the chemical.

Therefore, according to the magnetic resin composition according to the present embodiment, it is possible to obtain a molded product having high chemical resistance and whose magnetic properties are unlikely to deteriorate even when exposed to chemicals.

2. Details <Magnetic resin composition>
The magnetic resin composition according to the present embodiment includes a filler and a resin material. The magnetic resin composition may further contain a solvent. The shape of the magnetic resin composition is, for example, a paste, but a shape other than the paste may be used.

≪Filler≫
The filler contains a magnetic filler. The magnetic filler is a powdery substance that can be magnetized. As described above, when the filler contains the magnetic filler, a molded product having magnetic properties can be obtained. Magnetic properties are magnetic properties that are exhibited when magnetized. Specific examples of the magnetic characteristics include magnetic permeability and magnetic flux density.

As described above, the molded product has magnetic properties, but the molded product according to the present embodiment can have a high magnetic permeability at a high frequency. The high frequency frequency band is, for example, in the range of several tens of MHz or more and several GHz or less, and includes 100 MHz. Permeability, in particular, refers to the complex relative permeability (μ _r). The complex relative magnetic permeability (μ _r ) is _{expressed by the formula μ r} = μ / μ ₀ (μ: complex magnetic permeability, μ ₀ : vacuum magnetic permeability). The complex magnetic permeability (μ) is expressed by the formula μ = μ'-iμ "(μ': real part, μ": imaginary part, i: imaginary unit).

The filler may further contain a non-magnetic filler. The non-magnetic filler is a non-magnetic powdery substance.

[Magnetic filler]
The magnetic filler includes an iron-nickel alloy filler. The iron-nickel alloy filler is a magnetic filler made of an iron-nickel alloy. An iron-nickel alloy is a eutectic containing an iron element and a nickel element. The eutectic of the iron-nickel alloy may further contain a molybdenum element.

The nickel content is more than 39% by mass, preferably 45% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, based on the total mass of the iron-nickel alloy filler. be.

As described above, since the nickel content is higher than that of the conventional iron-nickel alloy filler, the chemical resistance of the molded product is increased. Here, the chemical resistance is a property that the molded product is not significantly deteriorated by the treatment of chemicals. The chemical treatment is not particularly limited, and examples thereof include desmear treatment, electroless plating, and electrolytic plating. Examples of the chemicals include chemicals for desmear treatment (chromic acid, sulfuric acid, neutralizers, conditioners, hydrofluoric acid, etc.), chemicals for electroless plating treatment, and plating solutions for electrolytic plating. The chemicals also include chemicals used for pre- and post-plating treatments. For example, acids such as sulfuric acid used in pretreatment of electroless plating (soft etching, pickling, predip, etc.) are also included.

When the chemical resistance of the molded product is increased, the performance of the molded product after being treated with the chemical is likely to be maintained as the performance of the molded product before being treated with the chemical. That is, even if the molded product having magnetic properties is exposed to chemicals, the molded product can maintain the magnetic properties before being exposed to the chemicals. As described above, the molded product according to the present embodiment is unlikely to deteriorate in magnetic properties even when treated with chemicals.

Further, since the nickel content is higher than that of the conventional iron-nickel alloy filler, the machinability of the molded product is improved. Here, the machinability is a degree indicating the ease of machining of a molded product. The machinability is not particularly limited, and examples thereof include hole machinability. The hole workability is a degree indicating the ease of processing the molded body when drilling a through hole in the molded body. The hole workability can be evaluated, for example, by the degree of wear of the drill bit.

When the machinability of the molded product, particularly the hole workability, is improved, for example, wear of the drill bit, unevenness of the hole wall, and generation of smear are reduced.

The upper limit of the nickel content with respect to the total mass of the iron-nickel alloy filler is not particularly limited, but is preferably 90% by mass or less, more preferably 85% by mass or less.

The content of the filler is preferably in the range of 30% by volume or more and 85% by volume or less, and more preferably 40% by volume or more and 75% by volume or less with respect to the total volume of the magnetic resin composition. When the filler content is 30% by volume or more, the magnetic permeability at high frequencies can be further increased. When the content of the filler is 85% by volume or less, the machinability can be improved. In particular, the hole workability can be improved.

The average particle size of the iron-nickel alloy filler is preferably 5 μm or less, more preferably 4 μm or less, still more preferably 3 μm or less. Here, the average particle size means the particle size at an integrated value of 50% in the particle size distribution measured based on the particle size distribution measuring device based on the laser scattering / diffraction method, that is, the 50% volume average particle size (D50). As described above, by reducing the average particle size of the iron-nickel alloy filler, the eddy current loss can be mainly reduced, and the magnetic loss at high frequencies can be reduced. Specifically, the loss coefficient (tan δ) can be reduced. The loss coefficient (tan δ) is expressed by the formula tan δ = μ ”/ μ’.

The iron-nickel alloy filler preferably contains spherical particles. This makes it possible to increase the filling of the iron-nickel alloy filler. That is, when the iron-nickel alloy filler contains spherical particles, the filling amount of the iron-nickel alloy filler in the magnetic filler can be increased as compared with the case where the iron-nickel alloy filler does not contain spherical particles. The iron-nickel alloy filler may contain particles having a shape other than spherical. The shape other than the spherical shape is not particularly limited, and examples thereof include an ellipsoidal shape, a flat shape, a crushed shape, and an indefinite shape.

As described above, when the iron-nickel alloy filler is highly filled, the magnetic permeability of the molded product can be increased even if the average particle size of the iron-nickel alloy filler is small. Further, the fluidity of the magnetic resin composition can be improved. That is, it becomes easy to mold the molded body.

Here, the case where the surface of the iron-nickel alloy filler is covered with an insulating layer (first case) and the case where the surface of the iron-nickel alloy filler is not covered with an insulating layer (second case) are determined. By comparison, the first case is preferable. That is, preferably, the surface of the iron-nickel alloy filler is coated with an insulating layer. More specifically, the surface of the individual particles constituting the iron-nickel alloy filler is coated with an insulating layer. In the second case, it is considered that the individual particles come into contact with each other and behave as a large mass of particles, but in the first case, the contact of the individual particles is suppressed by the insulating layer. Therefore, the insulating layer can suppress the generation of eddy currents flowing between the particles of the adjacent iron-nickel alloy filler. By reducing the eddy current loss in this way, the magnetic loss can be reduced.

The magnetic filler preferably further contains ferrite. Ferrite is a ceramic filler containing iron oxide as a main component. When the magnetic filler further contains ferrite, the magnetic permeability at high frequencies can be further increased.

Ferrites include soft ferrites exhibiting soft magnetism and hard ferrites exhibiting hard magnetism. Ferrites are classified into spinel ferrites, hexagonal ferrites, garnet ferrites, and the like according to their crystal structures.

Spinel ferrite has a spinel-type crystal structure. The composition formula of spinel ferrite is represented by AFe ₂ O ₄ (A is Mn, Co, Ni, Cu, Zn, etc.). Most of the spinel ferrites are soft ferrites. Spinel ferrite includes, for example, manganese-zinc ferrite, nickel-zinc ferrite, copper-zinc ferrite and the like. Since spinel ferrite has high magnetic permeability and electrical resistance, the eddy current loss in the high frequency frequency band is small. Magnetite is also a type of spinel ferrite. The composition formula of magnetite is represented by _{Fe 3} O _4.

Hexagonal ferrite has a magnetoplumbite-type hexagonal crystal structure. The composition formula of hexagonal ferrite is represented by AFe ₁₂ O ₁₉ (A is Ba, Sr, Pb, etc.). Hexagonal ferrite is also called magnetoplumbite-type ferrite or M-type ferrite. Hexagonal ferrite has a larger magnetic anisotropy than spinel ferrite, so it exhibits a large coercive force. Hexagonal ferrite is a typical hard ferrite.

Garnet ferrite has a garnet-type crystal structure. The composition formula of garnet ferrite is _{represented by RFe 5} O ₁₂ (R is a rare earth element). Garnet ferrite is also called Rare-earth Iron Garnet (RIG). A typical example of garnet ferrite is yttrium iron garnet (YIG). Garnet ferrite has a small magnetic loss at high frequencies.

When the magnetic filler further contains ferrite, the average particle size of the ferrite is preferably smaller than the average particle size of the iron-nickel alloy filler. As a result, the gaps between the particles of the iron-nickel alloy filler can be filled with ferrite. If there is a gap between the particles of the iron-nickel alloy filler, a demagnetic field can be generated in this gap. This demagnetic field can cause a decrease in magnetic permeability, but if the above gap is filled with ferrite, the magnetic permeability at high frequencies can be further increased.

If the magnetic filler further comprises ferrite, the ferrite preferably comprises spherical particles. This makes it possible to increase the filling of ferrite. That is, when the ferrite contains spherical particles, the filling amount of the ferrite in the magnetic filler can be increased as compared with the case where the ferrite does not contain spherical particles. The ferrite may contain particles having a shape other than spherical. The shape other than the spherical shape is not particularly limited, and examples thereof include an ellipsoidal shape, a flat shape, a crushed shape, and an indefinite shape.

As described above, when the ferrite is highly filled, the magnetic permeability of the molded product can be increased. Further, the fluidity of the magnetic resin composition can be improved. That is, it becomes easy to mold the molded body.

When the magnetic filler further contains ferrite, the content of ferrite is preferably 0.1 part by mass or more and 35 parts by mass or less, more preferably 1 part by mass, based on 100 parts by mass of the total of the iron-nickel alloy filler and the ferrite. It is within the range of 20 parts by mass or less. When the ferrite content is 0.1 parts by mass or more, the magnetic permeability at high frequencies can be further increased. When the ferrite content is 35 parts by mass or less, the thickening of the magnetic resin composition can be suppressed.

[Non-magnetic filler]
The non-magnetic filler is not particularly limited, and examples thereof include silica powder and alumina powder.

The silica powder may contain crystalline silica particles, amorphous silica particles, and the like.

The alumina powder may include α-alumina particles, γ-alumina particles, δ-alumina particles, θ-alumina particles, η-alumina particles, κ-alumina particles and the like.

≪Resin material≫
Resin materials include, for example, thermosetting resins, curing agents, curing accelerators, surface treatment agents, and the like.

[Thermosetting resin]
The thermosetting resin is not particularly limited, and examples thereof include a bisphenol F type epoxy resin, a bisphenol A type epoxy resin, a reactive diluent, and an alicyclic epoxy resin. Reactive diluents include alkyl diglycidyl ethers, alkyl monoglycidyl ethers, alkylphenol monoglycidyl ethers and the like.

Preferably, the thermosetting resin is liquid. When the thermosetting resin is liquid, it is easy to make the magnetic resin composition into a paste. The reactive diluent is effective in reducing the viscosity of the magnetic resin composition.

When the thermosetting resin contains an epoxy resin, the epoxy equivalent of the epoxy resin is not particularly limited, but is, for example, in the range of 100 g / eq or more and 200 g / eq or less.

[Curing agent]
The curing agent is not particularly limited, and examples thereof include acid anhydrides, phenols, polyamines, polyamides, and imidazole compounds. Acid anhydrides include methylbicyclo [2.2.1] heptane-2,3-dicarboxylic acid anhydride and bicyclo [2.2.1] heptane-2,3-dicarboxylic acid anhydride. Preferably, the curing agent is liquid. If the curing agent is liquid, it is easy to make the magnetic resin composition into a paste. When the curing agent contains acid anhydrides, the acid anhydride equivalent of the acid anhydrides is, for example, in the range of 170 or more and 190 or less. The imidazole compound is effective for storage stability and low viscosity of the magnetic resin composition. In addition, some curing agents can function as a curing accelerator.

[Curing accelerator]
The curing accelerator is not particularly limited, and examples thereof include an imidazole compound and the like. Preferably, the curing accelerator is encapsulated. If the curing accelerator is encapsulated, the storage stability of the magnetic resin composition can be improved. Further, by changing the film thickness of the capsule, the curing start temperature of the magnetic resin composition can be controlled, and the curing behavior can be adjusted according to the usage pattern. For example, if the film thickness of the capsule is reduced, the reaction can be started at a low temperature. On the other hand, if the film thickness of the capsule is increased, the reaction can be started at a high temperature and the storage stability at a low temperature and a normal temperature can be improved. In addition, some curing accelerators can function as a curing agent.

[Surface treatment agent]
Surface treatment agents are used to form an interface between a filler surface with different chemical properties and a resin material. The surface treatment agent is not particularly limited, and examples thereof include a silane coupling agent and a dispersant. The silane coupling agent and the dispersant can improve the dispersibility of the filler in the magnetic resin composition.

≪Solvent≫
The solvent is not particularly limited, and examples thereof include methyl ethyl ketone (MEK), N, N-dimethylformamide (DMF), acetone, and methyl isobutyl ketone (MIBK).

≪Form≫
Preferably, the magnetic resin composition is in the form of a liquid, a sheet, or a powder. This makes it possible to expand the applications.

<Molded body>
The molded product according to the present embodiment is made of a magnetic resin composition. Therefore, the molded product has high chemical resistance, and its magnetic properties are unlikely to deteriorate even when exposed to chemicals.

When the resin material contains a thermosetting resin, the molded product is obtained by heat-curing the magnetic resin composition. The molded product has the following magnetic properties.

That is, the real part (μ') of the complex magnetic permeability at 100 MHz of the molded product is preferably 6 or more, more preferably 8 or more. As a result, the magnetic permeability at high frequencies can be further increased.

The loss coefficient (tan δ) of the molded product at 100 MHz is preferably 0.1 or less, more preferably 0.08 or less. As a result, the loss can be further reduced.

The molded body can form a part of an insulating substrate used for manufacturing a printed wiring board. Even if the insulating substrate is treated with chemicals, the chemical resistance of the molded product is high, so that the magnetic properties of the molded product can be maintained. Therefore, it is possible to impart the magnetic characteristics of the molded product to the printed wiring board.

Further, the molded body may be used for manufacturing an inductor component. The inductor component includes a coiled wiring and an insulating layer that covers the coiled wiring. The insulating layer is the above-mentioned molded product. This makes it easier for the inductor component to control noise in the high frequency band. Inductor components include coils, inductors, filters, reactors, and transformers. The use of the inductor component is not particularly limited, and examples thereof include a noise filter component and an impedance matching circuit component. Examples of the noise filter include a low-pass filter and a common choke coil.

3. 3. Aspects As will be clear from the above embodiments, the present disclosure includes the following aspects.

The first aspect is a magnetic resin composition comprising a filler and a resin material. The filler contains a magnetic filler containing an iron-nickel alloy filler. The nickel content is more than 39% by mass with respect to the total mass of the iron-nickel alloy filler.

According to this aspect, it is possible to obtain a molded product having high chemical resistance and whose magnetic properties are unlikely to deteriorate even when exposed to chemicals.

The second aspect is a magnetic resin composition based on the first aspect. In the second aspect, the content of the filler is in the range of 30% by volume or more and 85% by volume or less with respect to the total volume of the magnetic resin composition.

According to this aspect, when the content of the filler is 30% by volume or more, the magnetic permeability at a high frequency can be further increased. When the content of the filler is 85% by volume or less, the machinability can be improved.

The third aspect is a magnetic resin composition based on the first or second aspect. In the third aspect, the average particle size of the iron-nickel alloy filler is 5 μm or less.

According to this aspect, the magnetic loss at high frequencies can be reduced.

The fourth aspect is a magnetic resin composition based on any one of the first to third aspects. In the fourth aspect, the iron-nickel alloy filler contains spherical particles.

According to this aspect, the iron-nickel alloy filler can be highly filled. By increasing the filling of the iron-nickel alloy filler, it is possible to increase the magnetic permeability even if the average particle size is small. The fluidity of the magnetic resin composition can also be improved.

A fifth aspect is a magnetic resin composition based on any one of the first to fourth aspects. In a fifth aspect, the magnetic filler further comprises ferrite.

According to this aspect, the magnetic permeability at high frequencies can be further increased.

A sixth aspect is a magnetic resin composition based on the fifth aspect. In the sixth aspect, the average particle size of the ferrite is smaller than the average particle size of the iron-nickel alloy filler.

According to this aspect, the gaps between the particles of the iron-nickel alloy filler can be filled with ferrite. As a result, the magnetic permeability at high frequencies can be further increased.

A seventh aspect is a magnetic resin composition based on the fifth or sixth aspect. In a seventh aspect, the ferrite comprises spherical particles.

According to this aspect, it is possible to increase the filling of ferrite. High magnetic permeability can be achieved by increasing the filling of ferrite. The fluidity of the magnetic resin composition can also be improved.

The eighth aspect is a magnetic resin composition based on any one of the fifth to eighth aspects. In the eighth aspect, the content of the ferrite is in the range of 0.1 part by mass or more and 35 parts by mass or less with respect to a total of 100 parts by mass of the iron-nickel alloy filler and the ferrite.

According to this aspect, when the ferrite content is 0.1 parts by mass or more, the magnetic permeability at high frequencies can be further increased. When the ferrite content is 35 parts by mass or less, the thickening of the magnetic resin composition can be suppressed.

A ninth aspect is a magnetic resin composition based on any one of the first to eighth aspects. In the ninth aspect, the surface of the iron-nickel alloy filler is coated with an insulating layer.

According to this aspect, the eddy current can be suppressed and the loss can be reduced.

A tenth aspect is a magnetic resin composition based on any one of the first to ninth aspects. In a tenth aspect, the magnetic resin composition is in the form of a liquid, a sheet, or a powder.

According to this aspect, the application can be expanded.

The eleventh aspect is a molded product, which is formed of a magnetic resin composition based on any one of the first to tenth aspects.

According to this aspect, the chemical resistance is high, and the magnetic properties are unlikely to deteriorate even when exposed to chemicals.

The twelfth aspect is a molded product based on the eleventh aspect. In the twelfth aspect, the real part (μ') of the complex magnetic permeability at 100 MHz of the molded product is 6 or more.

According to this aspect, the magnetic permeability at high frequencies can be further increased.

The thirteenth aspect is a molded article based on the eleventh or twelfth aspect. In the thirteenth aspect, the loss coefficient (tan δ) of the molded product at 100 MHz is 0.1 or less.

According to this aspect, the loss can be further reduced.

Hereinafter, the present disclosure will be specifically described with reference to Examples. However, the present disclosure is not limited to the examples.

A paste-like magnetic resin composition (hereinafter, also referred to as “magnetic paste”) was prepared. The raw materials for the magnetic paste are shown below.

≪Filler≫
[Fe-Ni alloy]
-Fe-36Ni (nickel content: 36% by mass, average particle size: 3 μm, particle shape: spherical, insulating layer: present)
-Fe-42Ni (nickel content: 42% by mass, average particle size: 3 μm, particle shape: spherical, insulating layer: present)
-Fe-50Ni (1) (nickel content: 50% by mass, average particle size: 3 μm, particle shape: spherical, insulating layer: yes)
-Fe-50Ni (2) (nickel content: 50% by mass, average particle size: 5 μm, particle shape: spherical, insulating layer: yes)
-Fe-50Ni (3) (nickel content: 50% by mass, average particle size: 6 μm, particle shape: spherical, insulating layer: yes)
-Fe-82Ni-5Mo (1) (nickel content: 82% by mass, molybdenum content: 5% by mass, average particle size: 3 μm, particle shape: spherical, insulating layer: yes)
Fe-82Ni-5Mo (2) (nickel content: 82% by mass, molybdenum content: 5% by mass, average particle size: 3 μm, particle shape: spherical, insulating layer: none)

[Ferrite]
-Magnetite (average particle size: 0.3 μm)
-Mn ferrite (1) (average particle size: 3.5 μm)
-Mn ferrite (2) (average particle size: 0.3 μm)

≪Resin material≫
[Thermosetting resin]
-Bisphenol F type epoxy resin (Nittetsu Chemical & Materials Co., Ltd., trade name "YDF-8170C", liquid, epoxy equivalent: 155 to 165 g / eq)
-Bisphenol A type epoxy resin (Nittetsu Chemical & Materials Co., Ltd., trade name "YD-8125", liquid, epoxy equivalent: 168 to 178 g / eq)
-Reactive diluent (Mitsubishi Chemical Corporation, trade name "YED216D", liquid, epoxy equivalent: 110-130 g / eq)
-Alicyclic epoxy resin (Daicel Co., Ltd., trade name "Selokiside 2021P", liquid, epoxy equivalent: 128 to 145 g / eq)

[Curing agent]
-Epoxy resin curing agent (New Japan Rika Co., Ltd., trade name "Ricacid HNA-100", acid anhydride, acid anhydride equivalent: 174 to 184)
・ Imidazole epoxy resin curing agent (Shikoku Kasei Kogyo Co., Ltd., trade name "2MAOK-PW", fine powder)

[Curing accelerator]
-Epoxy resin latent curing agent (Asahi Kasei Corporation, product name "Novacure HX-3722", capsule-type latent curing agent)

[Surface treatment agent]
・ Silane coupling agent (Momentive Performance Materials Japan GK, product name "Silquest A-187")
・ Dispersant (Big Chemie Japan Co., Ltd., product name "DISPERBYK-2152")

<Magnetic paste>
The above raw materials were blended so as to have the contents shown in Tables 1 to 5, and mixed uniformly to obtain a magnetic paste. A known mixer was used for mixing the raw materials.

<Evaluation>
The above magnetic paste was tested for the following evaluation items.

[viscosity]
The viscosity of the magnetic paste was measured using a rheometer "AR2000ex" manufactured by TA Instruments. Specifically, the gap between the upper and lower parallel plates having a diameter of 25 mm is set to 300 μm, and after filling this gap with magnetic paste, a temperature equilibrium time of 2 minutes is allowed at room temperature, and the rotation speed is set to 2.0 rpm. The viscosity was measured.

[Chixo Index]
In the same manner as the above viscosity measurement, the viscosity of the magnetic paste was measured at a rotation speed of 0.2 rpm. The chixo index of the magnetic paste was calculated by the following formula using the viscosity at a rotation speed of 0.2 rpm and the viscosity at a rotation speed of 2.0 rpm.
Chixo index = viscosity at 0.2 rpm / viscosity at 2.0 rpm

[chemical resistance]
The magnetic paste was heat-cured in the air to obtain a cured product. The heating conditions are 100 ° C. for 1 hour and then 150 ° C. for 1 hour. Further, the entire surface of the cured product was polished with No. 1500 abrasive paper so that the filler was exposed, to obtain an evaluation molded product (40 mm × 40 mm × thickness 0.5 mmt).

On the other hand, a desmear treatment solution (300 mL) was placed in a beaker. The desmear treatment liquid contains 100 mL / L of "Reduction Securigant P500" manufactured by Atotech Co., Ltd. and 50 mL / L of a 98% sulfuric acid aqueous solution.

Then, the evaluation molded product was immersed in the desmear treatment liquid in the beaker, and the presence or absence of foaming on the surface of the evaluation molded product was confirmed over time. Judgment was made according to the following criteria.
S: No foaming on the surface of the evaluation molded product is confirmed even after immersion for 20 minutes A: No foaming is confirmed on the surface of the evaluation molded product even after immersion for 10 minutes B: For evaluation after immersion for less than 10 minutes Foaming on the surface of the molded product is confirmed.

[Hole workability]
The magnetic paste was heat-cured in the atmosphere to obtain an evaluation molded product (100 mm × 100 mm × thickness 1.0 mmt). The heating conditions are 100 ° C. for 1 hour and then 150 ° C. for 1 hour.

Next, a through hole of 3000 holes was machined in the evaluation molded product using "ND-1S211" manufactured by Via Mechanics. As for the processing conditions, a drill bit (Φ0.15 mm) was rotated at a speed of 80 krpm, and a hole was drilled at a feed rate of 0.8 m / min and a pitch of 1.0 mm.

Then, by comparing the photographs from the front of the drill bit before and after the drilling process for 3000 holes, the area ratio at which the drill bit was scraped due to the wear caused by the drilling process was calculated, and this was calculated as the drill bit wear rate (%). And said. A drill bit wear rate of less than 20% is good.

[Magnetic characteristics]
The magnetic paste was heat-cured in the atmosphere to obtain a ring-shaped evaluation molded product (outer diameter 7.0 mm, inner diameter 3.5 mm, thickness 1.0 mmt). The heating conditions are 100 ° C. for 1 hour and then 150 ° C. for 1 hour.

Next, the complex magnetic permeability at 100 MHz of the ring-shaped evaluation molded product was measured using a “4291A RF impedance / material analyzer” manufactured by Hewlett-Packard Company. The measurement was performed at room temperature with the current frequency in the range of 1 MHz or more and 1.8 GHz or less. From initial magnetization curve obtained by measuring the real part (mu '), the imaginary part to obtain a (mu "), these were calculated permeability (complex permeability (mu _r)) and loss factor (tan [delta) ..

Claims (13)

With a filler and a resin material,
The filler contains a magnetic filler containing an iron-nickel alloy filler, and the filler contains a magnetic filler.
The nickel content is more than 39% by mass with respect to the total mass of the iron-nickel alloy filler.
Magnetic resin composition. The content of the filler is in the range of 30% by volume or more and 85% by volume or less with respect to the total volume of the magnetic resin composition.
The magnetic resin composition according to claim 1. The average particle size of the iron-nickel alloy filler is 5 μm or less.
The magnetic resin composition according to claim 1 or 2. The iron-nickel alloy filler contains spherical particles.
The magnetic resin composition according to any one of claims 1 to 3. The magnetic filler further contains ferrite.
The magnetic resin composition according to any one of claims 1 to 4. The average particle size of the ferrite is smaller than the average particle size of the iron-nickel alloy filler.
The magnetic resin composition according to claim 5. The ferrite contains spherical particles,
The magnetic resin composition according to claim 5 or 6. The content of the ferrite is in the range of 0.1 parts by mass or more and 35 parts by mass or less with respect to a total of 100 parts by mass of the iron-nickel alloy filler and the ferrite.
The magnetic resin composition according to any one of claims 5 to 7. The surface of the iron-nickel alloy filler is coated with an insulating layer.
The magnetic resin composition according to any one of claims 1 to 8. The magnetic resin composition is in the form of a liquid, a sheet, or a powder.
The magnetic resin composition according to any one of claims 1 to 9. The magnetic resin composition according to any one of claims 1 to 10.
Molded body. The real part (μ') of the complex magnetic permeability at 100 MHz of the molded product is 6 or more.
The molded product according to claim 11. The loss coefficient (tan δ) of the molded product at 100 MHz is 0.1 or less.
The molded product according to claim 11 or 12.