Soft magnetic resin composition, soft magnetic thin film, inductor, and method for producing soft magnetic thin film

Abstract

The soft magnetic resin composition contains: a solid component containing flat soft magnetic particles and a resin component; and a dispersion medium. In addition, the viscosity (A) at a shear rate of 38.1 s <-1 > is 300 mPa * s or more. Furthermore, the ratio (A / C) of the viscosity (A) at a shear rate of 38.1 s <-1 > to the viscosity (C) at a shear rate of 191.5 s <-1 > is 1.7 or more.

Description

Technical Field

[0001] This disclosure relates to a soft magnetic resin composition, a soft magnetic film and an inductor using the soft magnetic resin composition, and a method for manufacturing a soft magnetic film using the soft magnetic resin composition. Background Technology

[0002] In recent years, the integration of wireless communication or wireless power transmission has become increasingly widespread in electronic devices such as personal computers and smartphones. Moreover, in order to extend the wireless communication distance, increase efficiency, and miniaturize electronic devices, soft magnetic films that concentrate magnetic flux are placed around antennas, coils, and other components of the electronic devices.

[0003] Such a soft magnetic film is formed from a soft magnetic resin composition comprising flattened soft magnetic particles, a resin component, and a dispersion medium (see, for example, Patent Document 1). Specifically, the soft magnetic resin composition is applied to a release liner using an applicator, and after the coated film is dried, it is hot-pressed to manufacture the soft magnetic film.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2015-092543 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] On the other hand, for soft magnetic films, excellent magnetic properties are required, which in turn enable stable and efficient continuous production.

[0009] However, in the case of forming the soft magnetic film of Patent Document 1, the viscosity of the soft magnetic resin composition is insufficient. Therefore, the soft magnetic particles in the soft magnetic resin composition tend to settle and exist unevenly, resulting in the inability to stably form a uniform soft magnetic film. Such defects are particularly likely to occur when the soft magnetic resin composition is coated at high speed and continuously to form a soft magnetic film.

[0010] This disclosure provides a soft magnetic resin composition capable of stable and efficient continuous production of soft magnetic films with excellent magnetic properties, a soft magnetic film using the soft magnetic resin composition and an inductor, and a method for manufacturing a soft magnetic film using the soft magnetic resin composition.

[0011] Solution for solving the problem

[0012] This disclosure [1] includes a soft magnetic resin composition comprising a solid component and a dispersion medium, the solid component comprising flattened soft magnetic particles and a resin component, the soft magnetic resin composition having a shear rate of 38.1 s.-1 The viscosity (A) is above 300 mPa·s, and the shear rate of the soft magnetic resin composition is 38.1 s⁻¹. -1 The viscosity (A) at the specified shear rate is 191.5 s⁻¹. -1 The viscosity (C) ratio (A / C) is 1.70 or higher.

[0013] This disclosure [2] includes the soft magnetic resin composition described in [1] above, wherein the cumulative value of the volume reference of the aforementioned flat soft magnetic particles from the small particle size side is 90% of the particle size (D90) of 80 μm or more and 130 μm or less.

[0014] This disclosure [3] includes the soft magnetic resin composition described in [1] or [2] above, wherein the cumulative value of the volume reference of the aforementioned flat soft magnetic particles from the small particle size side is 50% and the particle size (D50) is 30 μm or more and 50 μm or less.

[0015] This disclosure [4] includes the soft magnetic resin composition described in any one of [1] to [3] above, wherein the cumulative value of the volume reference of the aforementioned flat soft magnetic particles from the small particle size side is 10% and the particle size (D10) is 5 μm or more.

[0016] This disclosure [5] includes any one of the above [1] to [4] soft magnetic resin compositions, wherein the concentration of the solid components of the aforementioned soft magnetic resin compositions is 11% by volume or more and 14% by volume or less.

[0017] This disclosure [6] includes any one of the above [1] to [5] soft magnetic resin compositions, wherein the aforementioned resin components comprise thermosetting resin components and thermoplastic resin components.

[0018] This disclosure [7] includes the soft magnetic resin composition described above [6], wherein the aforementioned thermosetting resin component comprises an epoxy resin and the aforementioned thermoplastic resin component comprises an acrylic resin.

[0019] This disclosure [8] includes the soft magnetic resin composition described above [7], wherein the aforementioned thermosetting resin component further comprises a curing agent and a curing accelerator.

[0020] This disclosure [9] includes any one of the soft magnetic resin compositions described in [1] to [8] above, wherein the content of the aforementioned flat soft magnetic particles in the solid component of the aforementioned soft magnetic resin composition is 45% by volume or more and 70% by volume or less.

[0021] This disclosure

[10] includes any one of the soft magnetic resin compositions described in [1] to [9] above, wherein the cured soft magnetic resin composition has a permeability of 40 or more at a frequency of 10 MHz.

[0022] This disclosure

[11] includes a soft magnetic film, which is a cured product of the soft magnetic resin composition described in any one of [1] to

[10] above.

[0023] This disclosure

[12] includes an inductor having the soft magnetic thin film and wiring described above

[11] .

[0024] This disclosure

[13] includes a method for manufacturing a soft magnetic film, comprising the following steps: a coating step, wherein the soft magnetic resin composition described in any one of [1] to

[10] is coated onto a substrate at a coating speed of 5 m / min or more; a drying step, wherein the dispersion medium contained in the soft magnetic resin composition coated onto the substrate is dried to obtain a semi-cured soft magnetic film; and a curing step, wherein the semi-cured soft magnetic film is thermally cured.

[0025] This disclosure

[14] includes a method for manufacturing the soft magnetic film described in

[13] above, wherein, in the aforementioned coating process, the coating speed is continuously or intermittently increased until the coating speed reaches 5 m / min or more.

[0026] The effects of the invention

[0027] This disclosure pertains to a soft magnetic resin composition comprising flattened soft magnetic particles, a resin component, and a dispersion medium, wherein the soft magnetic resin composition has a shear rate of 38.1 s⁻¹. -1 The viscosity (A) is above 300 mPa·s, and the shear rate of the soft magnetic resin composition is 38.1 s⁻¹. -1 The viscosity (A) at the specified shear rate is 191.5 s⁻¹. -1 The viscosity-to-b viscosity ratio (A / B) is 1.7 or higher. Therefore, it is possible to stably and efficiently produce soft magnetic films with excellent viscosity and magnetic properties during continuous coating.

[0028] The soft magnetic film disclosed herein is formed from the soft magnetic resin composition disclosed herein. Therefore, it exhibits excellent magnetic properties and can be produced continuously and stably with high efficiency.

[0029] The inductor disclosed herein comprises the soft magnetic thin film of this disclosure. Therefore, it exhibits excellent magnetic properties.

[0030] The method for manufacturing the soft magnetic film disclosed herein includes a step of coating the soft magnetic resin composition disclosed herein onto a substrate at a coating speed of 5 m / min or more. Therefore, it is possible to stably and efficiently produce soft magnetic films continuously. Attached Figure Description

[0031] Figure 1 A cross-sectional view of an inductor according to one embodiment of the present disclosure is shown.

[0032] Figure 2 : Figure 2 A~ Figure 2 C is Figure 1 The diagram shows the manufacturing process of one embodiment of the inductor. Figure 2 A shows the preparation process. Figure 2 B shows the configuration process. Figure 2 C indicates the curing process.

[0033] Figure 3 A cross-sectional view of a magnetic wiring circuit board using the soft magnetic thin film of this disclosure is shown.

[0034] Figure 4 The shear rates (s) of each embodiment and comparative example are shown. -1 A graph showing the relationship between viscosity (mPa·s). Detailed Implementation

[0035] 1. Soft magnetic resin composition

[0036] The soft magnetic resin composition disclosed herein comprises a solid component and a dispersion medium, wherein the solid component comprises flattened soft magnetic particles and a resin component. It should be noted that the soft magnetic resin composition may include other additives described later, as needed.

[0037] <Flat, soft magnetic particles>

[0038] Flat, soft magnetic particles are soft magnetic particles with a flat (plate-like) shape. That is, flat, soft magnetic particles are soft magnetic particles formed with a thin thickness and a wide surface area. It should be noted that soft magnetic particles are, for example, magnetic particles with characteristics such as low coercivity, high permeability, easy magnetization when a magnetic field is applied, and easy return to their original shape when the magnetic field is removed.

[0039] Such flat, soft magnetic particles can be produced by, for example, by pulverizing soft magnetic materials into powder and then processing the resulting soft magnetic particles into a flat shape (flattening process).

[0040] There are no particular limitations on what constitutes a soft magnetic material; examples include magnetic stainless steel (Fe-Cr-Al-Si alloy), iron-silicon-aluminum magnetic alloy (Fe-Si-Al alloy), permalloy (Fe-Ni alloy), silicon-copper (Fe-Cu-Si alloy), Fe-Si alloy, Fe-Si-B (-Cu-Nb) alloy, Fe-Si-Cr-Ni alloy, Fe-Si-Cr alloy, Fe-Si-Al-Ni-Cr alloy, and ferrite. From the viewpoint of magnetic properties, Fe-Si alloy is preferred as a soft magnetic material.

[0041] Soft magnetic materials can be used alone or in combination.

[0042] Soft magnetic materials can be pulverized by methods such as gas atomization, water atomization, disc atomization, and pulverization. Gas atomization is a preferred method for pulverization.

[0043] Specifically, as a gas atomization method, firstly, the soft magnetic material is heated and melted to obtain a molten liquid. Next, the molten liquid is allowed to flow out from a nozzle, into which a gas (such as argon or nitrogen) is blown. The molten liquid is condensed into droplets by the energy of the gas. These droplets solidify as they fall and are cooled, forming powder or particles. In this way, the soft magnetic material can be pulverized to obtain soft magnetic particles.

[0044] In the gas atomization method, the molten liquid is instantaneously dropletized and simultaneously cooled, resulting in soft magnetic particles with a uniform microstructure. Furthermore, due to the continuous formation of droplets, the compositional differences between the soft magnetic particles become extremely small.

[0045] It should be noted that the obtained soft magnetic particles can be graded before flattening.

[0046] Flattening of soft magnetic particles can be achieved using, for example, a grinding mill.

[0047] It should be noted that the processing conditions of the grinding mill are not particularly limited as long as they can process the particles into flat, soft magnetic particles with the specific particle size distribution described later.

[0048] The flattening of soft magnetic particles can be done using either wet or dry methods. Wet processing is preferred for flattening soft magnetic particles.

[0049] In wet processing, it is preferable to use organic solvents that can inhibit oxidation during processing.

[0050] As an organic solvent, there are no particular limitations as long as it can inhibit oxidation during processing; alcohols are an example.

[0051] The amount of organic solvent added can be adjusted appropriately according to the type of soft magnetic particles.

[0052] It should be noted that the obtained flat, soft magnetic particles can be heat-treated as needed, or they can be graded.

[0053] The flattened soft magnetic particles have a flatness ratio or flatness of, for example, 8 or more and 80 or less, preferably 15 or more and 65 or less.

[0054] It should be noted that the flatness of the flat soft magnetic particles is calculated, for example, in the form of the aspect ratio obtained by dividing D50 by the average thickness of the flat soft magnetic particles, where D50 is the cumulative value of the volume reference of the flat soft magnetic particles from the small particle size side, which is 50% of the particle size.

[0055] The cumulative value of the volume reference from the small particle size side of the flat soft magnetic particles is 90%, and the particle size D90 is, for example, 60 μm or more and 150 μm or less, preferably 70 μm or more and 140 μm or less, more preferably 80 μm or more and 130 μm or less, further preferably 80 μm or more and 110 μm or less, and especially preferably 80 μm or more and 100 μm or less.

[0056] If the particle size D90 of the flattened soft magnetic particles is above or above the aforementioned lower limit, the magnetic properties of the soft magnetic film are improved. Furthermore, if the particle size D90 of the flattened soft magnetic particles is below or above the aforementioned upper limit, the sedimentation of the flattened soft magnetic particles in the soft magnetic resin composition can be suppressed, thereby suppressing unevenness during coating of the soft magnetic resin composition.

[0057] The cumulative value of the volume reference from the small particle size side of the flat soft magnetic particles, which is 50% of the particle size, i.e., D50, is, for example, 20 μm or more and 100 μm or less, preferably 25 μm or more and 75 μm or less, more preferably 30 μm or more and 50 μm or less, further preferably 35 μm or more and 50 μm or less, and especially preferably 38 μm or more and 47 μm or less.

[0058] If the particle size D50 of the flat soft magnetic particles is within the above range, the magnetic properties of the soft magnetic film will be improved.

[0059] The cumulative value of the volume reference from the small particle size side of the flat soft magnetic particles is 10%, and the particle size D10 is, for example, 5 μm or more and 50 μm or less, preferably 10 μm or more and 30 μm or less, more preferably 12 μm or more and 20 μm or less, and even more preferably 13 μm or more and 17 μm or less.

[0060] The cumulative value of the volume reference from the smallest particle size side of the flat soft magnetic particles, which is 10%, has a particle size D10 of, for example, 5 μm or more, preferably 10 μm or more, more preferably 12 μm or more, further preferably 13 μm or more, especially preferably more than 13 μm, and also, for example, 50 μm or less, preferably 30 μm or less, more preferably 20 μm or less, and further preferably 17 μm or less.

[0061] If the particle size D10 of the flat soft magnetic particles is above the lower limit mentioned above, the appearance and other properties of the soft magnetic film are excellent, and thus the magnetic properties of the soft magnetic film are improved.

[0062] Flattened soft magnetic particles with the aforementioned particle size distribution can be obtained, for example, by adjusting the conditions for flattening spherical soft magnetic particles using a grinding mill or similar equipment. Alternatively, they can be obtained by classifying the flattened soft magnetic particles using a classifier such as a dry classifier. It should be noted that, as described above, by classifying the soft magnetic particles before flattening as needed, the final particle size distribution (the particle size distribution of the flattened soft magnetic particles after flattening) can also be adjusted.

[0063] Furthermore, to obtain flattened soft magnetic particles with the aforementioned particle size, two or more types of flattened soft magnetic particles with different particle sizes (particle size distributions) can be mixed. That is, flattened soft magnetic particles with a specific particle size can be used individually, or two or more types of flattened soft magnetic particles with different particle sizes (particle size distributions) can be used together. It should be noted that when using two or more types of flattened soft magnetic particles with different particle sizes (particle size distributions), the particle size of each flattened soft magnetic particle before mixing does not need to be within the aforementioned range; it is sufficient to adjust the particle size of the mixed flattened soft magnetic particles to be within the aforementioned range.

[0064] The particle sizes D10, D50, and D90 of flattened soft magnetic particles can be determined, for example, using a laser diffraction particle size analyzer (Beckman Coulter, LS 13 320). Specifically, the particle size distribution of magnetic powder can be prepared on a volume basis using a laser diffraction particle size analyzer, and D10, D50, and D90 can be measured. The sample can be obtained by dispersing the flattened soft magnetic particles in pure water using ultrasound.

[0065] The coercivity of the flat, soft magnetic particles is, for example, 10 A / m or more and 1000 A / m or less, preferably 50 A / m or more and 200 A / m or less.

[0066] Coercivity can be measured, for example, by a vibrating sample magnetometer.

[0067] The specific gravity of the flat, soft magnetic particles is, for example, 5.0 or more and 8.5 or less, preferably 6.0 or more and 8.0 or less.

[0068] The proportion (mass ratio) of flattened soft magnetic particles in the solid component of the soft magnetic resin composition is, for example, 70% by mass or more and 95% by mass or less, preferably 80% by mass or more and 92% by mass or less, more preferably 85% by mass or more and 90% by mass or less, and even more preferably 87% by mass or more and 90% by mass or less.

[0069] The proportion (volume percentage) of flattened soft magnetic particles in the solid component of the soft magnetic resin composition is, for example, 40% or more and 80% or less, preferably 45% or more and 70% or less, more preferably 50% or more and 70% or less, further preferably 53% or more and 60% or less, and especially preferably 55% or more and 57% or less.

[0070] If the proportion of flat, soft magnetic particles in the solid component of the soft magnetic resin composition is at or above the aforementioned lower limit, the soft magnetic film exhibits excellent magnetic properties. Furthermore, if the proportion of flat, soft magnetic particles in the solid component of the soft magnetic resin composition is below the aforementioned upper limit, the content of the resin component described later can be sufficiently ensured, resulting in excellent film-forming properties of the soft magnetic film.

[0071] It should be noted that the volume ratios of the components, such as the flat, soft magnetic particles, are calculated based on the theoretical volume obtained by dividing the mass of each component by its specific gravity (the same applies below). The specific gravity of each component is obtained from catalog values ​​or known measurement methods (e.g., specific gravity determination).

[0072] Furthermore, the solids component of the soft magnetic resin composition refers to the solids component comprising the flattened soft magnetic particles and the resin component described later. Other additives described later may also be included, if necessary. It should be noted that, in the absence of other additives, the solids component of the soft magnetic resin composition refers to the total amount of the flattened soft magnetic particles and the resin component.

[0073] The proportion (mass percentage) of flattened soft magnetic particles in the soft magnetic resin composition is, for example, 20% by mass or more and 50% by mass or less, preferably 30% by mass or more and 45% by mass or less, more preferably 35% by mass or more and 40% by mass or less, and even more preferably 36% by mass or more and 40% by mass or less.

[0074] The proportion (volume percentage) of flattened soft magnetic particles in the soft magnetic resin composition is, for example, 3.0 vol% or more and 15.0 vol% or less, preferably 5.0 vol% or more and 10.0 vol% or less, more preferably 5.5 vol% or more and 8.0 vol% or less, and even more preferably 6.0 vol% or more and 8.0 vol% or less.

[0075] If the proportion of flat, soft magnetic particles in the soft magnetic resin composition is at or above the lower limit mentioned above, the viscosity of the soft magnetic resin composition at rest (viscosity at low shear rates) can be sufficiently ensured. Therefore, the sedimentation and uneven presence of the flat, soft magnetic particles can be suppressed, and the flat, soft magnetic particles can be highly packed, thereby improving magnetic properties. Furthermore, if the proportion of flat, soft magnetic particles in the soft magnetic resin composition is below the upper limit mentioned above, the flowability of the soft magnetic resin composition can be improved (viscosity at high shear rates can be reduced) when coating the soft magnetic resin composition. Therefore, the soft magnetic resin composition can be continuously coated stably and efficiently.

[0076] <Resin Composition>

[0077] The resin component may include, for example, at least one of a thermosetting resin component and a thermoplastic resin component. Preferably, the resin component includes both a thermosetting resin component and a thermoplastic resin component. The resin component may also include additives as needed. It should be noted that the additives listed below are the same additives as others described later.

[0078] When the resin composition contains both thermosetting resin and thermoplastic resin components, as detailed below, when multiple layers of soft magnetic films before complete curing are stacked to manufacture a soft magnetic film, a soft magnetic film with no unevenness at the stacking interface, uniformity, and good magnetic permeability can be obtained.

[0079] [Thermosetting resin composition]

[0080] As a thermosetting resin component, it may include, for example, thermosetting resin, curing agent, and curing accelerator.

[0081] Examples of thermosetting resins include epoxy resins. Other examples of thermosetting resins include amino resins, unsaturated polyester resins, polyurethane resins, silicone resins, urea resins, melamine resins, thermosetting polyimide resins, and diallyl phthalate resins. Epoxy resins are preferably included as thermosetting resins.

[0082] Thermosetting resins can be used alone or in combination of two or more types.

[0083] Examples of epoxy resins include bisphenol-type epoxy resins (such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, brominated bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol AF type epoxy resin, etc.), phenol-type epoxy resins (such as phenolic varnish type epoxy resin, o-cresolic varnish type epoxy resin, etc.), biphenyl-type epoxy resins, naphthalene-type epoxy resins, fluorene-type epoxy resins, trihydroxyphenylmethane type epoxy resins, tetrahydroxyphenylethane type epoxy resins, hydantoin type epoxy resins, triglycidyl isocyanurate type epoxy resins, and glycidylamine type epoxy resins. Phenolic-type epoxy resins are preferred, and o-cresolic varnish type epoxy resins are more preferred.

[0084] Epoxy resins can be used alone or in combination of two or more types.

[0085] If the thermosetting resin is an epoxy resin, it has excellent reactivity with the curing agent (e.g., phenolic resin) described later, resulting in excellent heat resistance and magnetic permeability of the soft magnetic film.

[0086] The epoxy equivalent of the epoxy resin is, for example, 50 g / eq. or more and 300 g / eq. or less, preferably 100 g / eq. or more and 250 g / eq. or less.

[0087] The density of epoxy resin is, for example, 0.8 g / cm³. 3 Above and 1.5g / cm 3 The preferred value is 1.0 g / cm³. 3 Above and 1.3g / cm 3 the following.

[0088] The proportion of thermosetting resin in the resin composition is, for example, 10% or more and 50% or less by mass, preferably 15% or more and 40% or less by mass, more preferably 20% or more and 35% or less by mass, and even more preferably 25% or more and 30% or less by mass.

[0089] Phenolic resins can be cited as examples of curing agents. That is, phenolic resins are used, for example, as curing agents for epoxy resins.

[0090] Examples of phenolic resins include phenolic varnish-type phenolic resins (such as phenolic varnish resins, phenolic aralkyl resins, cresol phenolic varnish resins, tert-butylphenol phenolic varnish resins, nonylphenol phenolic varnish resins, etc.) and methyl-type phenolic resins (such as poly(para-oxystyrene) and other polyoxystyrene). Phenolic varnish-type phenolic resins are preferred, and phenolic aralkyl resins are more preferred. Specifically, biphenyl aralkyl-type phenolic resins are even more preferred.

[0091] Phenolic resins can be used alone or in combination of two or more types.

[0092] If the curing agent is phenolic resin, the heat resistance of the soft magnetic film can be improved when it is used in inductors or circuit boards.

[0093] The hydroxyl equivalent of the phenolic resin is, for example, 50 g / eq. or more and 300 g / eq. or less, preferably 100 g / eq. or more and 250 g / eq. or less.

[0094] The density of phenolic resin is, for example, 0.8 g / cm³. 3 Above and 1.5g / cm 3 The preferred value is 1.0 g / cm³. 3 Above and 1.3g / cm 3 the following.

[0095] The content of curing agent in the resin component is, for example, 10% or more and 50% or less by mass, preferably 15% or more and 40% or less by mass, more preferably 20% or more and 35% or less by mass, and even more preferably 25% or more and 30% or less by mass.

[0096] As a curing accelerator, examples include catalysts that promote the curing of thermosetting resins by heating.

[0097] Examples of curing accelerators include imidazole compounds, triphenylphosphine compounds, triphenylborane compounds, and amino-containing compounds, with imidazole compounds being the preferred example.

[0098] Examples of imidazole compounds include 2-phenylimidazolium (trade name "2PZ"), 2-ethyl-4-methylimidazolium (trade name "2E4MZ"), 2-methylimidazolium (trade name "2MZ"), 2-undecylimidazolium (trade name "C11Z"), 2-phenyl-4,5-dihydroxymethylimidazolium (trade name "2-PHZ"), 2-phenyl-1H-imidazolium-4,5-diethanol (trade name "2PHZ-PW"), and 2,4-diamino-6-(2'-methylimidazolyl(1)')ethyl-triazine isocyanuric acid adduct (trade name "2MAOK-PW"), with 2-phenyl-1H-imidazolium-4,5-diethanol being a preferred example (all of the above trade names are manufactured by Shikoku Chemical Co., Ltd.).

[0099] Curing accelerators can be used alone or in combination of two or more.

[0100] The density of the curing accelerator is, for example, 1.0 g / cm³. 3 Above and 1.8g / cm 3 The preferred value is 1.2 g / cm³. 3 Above and 1.5g / cm 3 the following.

[0101] The content of the curing accelerator in the resin component is, for example, 0.1% by mass or more and 5.0% by mass or less, preferably 0.3% by mass or more and 3.0% by mass or less, more preferably 0.5% by mass or more and 2.0% by mass or less, and even more preferably 0.7% by mass or more and 1.5% by mass or less.

[0102] When the content of the curing accelerator in the resin component is below the upper limit mentioned above, the soft magnetic resin composition can maintain good long-term shelf life at room temperature. On the other hand, when the content of the curing accelerator is above the lower limit mentioned above, the soft magnetic film before complete curing can be cured by heating at a low temperature and for a short time, thus efficiently manufacturing the soft magnetic film.

[0103] The proportion (mass percentage) of the thermosetting resin component in the resin composition is, for example, 25% by mass or more and 90% by mass or less, preferably 35% by mass or more and 80% by mass or less, more preferably 45% by mass or more and 70% by mass or less, and even more preferably 50% by mass or more and 60% by mass or less.

[0104] The proportion (volume percentage) of the thermosetting resin component in the resin composition is, for example, 25% or more and 85% or less, preferably 35% or more and 75% or less, more preferably 45% or more and 65% or less, and even more preferably 50% or more and 55% or less.

[0105] [Thermoplastic resin composition]

[0106] The thermoplastic resin component may include, for example, a thermoplastic resin. Preferably, the thermoplastic resin component is composed of a thermoplastic resin.

[0107] Examples of thermoplastic resins include acrylic resins, natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, ethylene-vinyl acetate copolymer, polybutadiene resin, polycarbonate resin, thermoplastic polyimide resin, polyamide resin (e.g., 6-nylon, 6,6-nylon, etc.), phenoxy resins, saturated polyester resins (e.g., PET, PBT, etc.), polyamide-imide resins, and fluororesins, with acrylic resins being the preferred example.

[0108] Thermoplastic resins can be used alone or in combination of two or more types.

[0109] Examples of acrylic resins include acrylate polymers obtained by polymerizing one or more alkyl (meth)acrylates having straight or branched alkyl groups as monomer components. It should be noted that "(meth)acrylate" refers to "acrylic acid and / or methacrylic acid".

[0110] The weight-average molecular weight of acrylic resins is, for example, 1 × 10⁻⁶. 5 The above is preferably 3×10 5 The above, and also, for example, 1×10 6 the following.

[0111] If the weight-average molecular weight of the acrylic resin is within the above range, the soft magnetic film will have excellent adhesion and heat resistance.

[0112] It should be noted that the weight-average molecular weight was determined using gel permeation chromatography (GPC) and converted from the standard polystyrene value.

[0113] It should be noted that the glass transition temperature is obtained from the maximum value of the loss tangent (tanδ) measured using a dynamic viscoelasticity measuring device (DMA, frequency 1Hz, heating rate 10℃ / min).

[0114] The density of thermoplastic resin is, for example, 0.5 g / cm³. 3 Above and 1.5g / cm 3 The preferred value is 0.8 g / cm³. 3 Above and 1.2g / cm 3 the following.

[0115] The proportion (mass percentage) of thermoplastic resin component in the resin composition is, for example, 20% or more and 75% or less by mass, preferably 30% or more and 65% or less by mass, more preferably 35% or more and 55% or less by mass, and even more preferably 40% or more and 50% or less by mass.

[0116] The proportion (volume percentage) of thermoplastic resin component in the resin composition is, for example, 25% or more and 80% or less, preferably 35% or more and 70% or less, more preferably 40% or more and 60% or less, and even more preferably 45% or more and 50% or less.

[0117] If the proportion of thermoplastic resin component in the resin composition is within the above range, the soft magnetic resin composition exhibits excellent film-forming properties and adhesion of the soft magnetic film before complete curing.

[0118] In addition, the proportion (mass ratio) of the resin component in the solid component of the soft magnetic resin composition is, for example, 3% by mass or more and 30% by mass or less, preferably 5% by mass or more and 20% by mass or less, and more preferably 8% by mass or more and 15% by mass or less.

[0119] The proportion (volume percentage) of the resin component in the solid component of the soft magnetic resin composition is, for example, 20% or more and 70% or less by volume, preferably 30% or more and 60% or less by volume, more preferably 35% or more and 50% or less by volume, and even more preferably 40% or more and 50% or less by volume.

[0120] If the proportion of resin component in the solid component of the soft magnetic resin composition is above or below the aforementioned lower limit, the film-forming properties of the soft magnetic film are excellent. Furthermore, if the proportion of resin component in the solid component of the soft magnetic resin composition is below or below the aforementioned upper limit, the proportion of flattened soft magnetic particles can be ensured, resulting in excellent magnetic properties of the soft magnetic film.

[0121] The concentration (mass percentage) of the resin component in the soft magnetic resin composition is, for example, 2.0% by mass or more and 10.0% by mass or less, preferably 3.0% by mass or more and 8.0% by mass or less, more preferably 4.0% by mass or more and 5.0% by mass or less, and even more preferably 4.3% by mass or more and 5.0% by mass or less.

[0122] The concentration (volume percentage) of the resin component in the soft magnetic resin composition is, for example, 2.0 vol% or more and 10.0 vol% or less, preferably 3.5 vol% or more and 8.0 vol% or less, more preferably 4.5 vol% or more and 6.0 vol% or less, and even more preferably 4.8 vol% or more and 6.0 vol% or less.

[0123] If the concentration of the resin component in the soft magnetic resin composition is above or below the aforementioned lower limit, the viscosity of the soft magnetic resin composition at rest (viscosity at low shear rates) can be sufficiently ensured, thus suppressing the sedimentation and uneven presence of flattened soft magnetic particles. Furthermore, if the concentration of the resin component in the soft magnetic resin composition is below or below the aforementioned upper limit, the flowability of the soft magnetic resin composition can be improved (viscosity at high shear rates) when coating the soft magnetic resin composition, thus enabling stable and efficient continuous coating of the soft magnetic resin composition.

[0124] <Dispersion Medium>

[0125] In the soft magnetic resin composition, flat soft magnetic particles and resin components are dispersed in a dispersion medium.

[0126] Examples of dispersion media include ketones such as acetone and methyl ethyl ketone (MEK), esters such as ethyl acetate, amides such as N,N-dimethylformamide, ethers such as propylene glycol monomethyl ether, and organic solvents such as methanol, ethanol, propanol, and isopropanol. Aqueous solvents (e.g., water) can also be used as dispersion media. Ketones are preferred as dispersion media, and methyl ethyl ketone is more preferred.

[0127] The concentration (mass ratio) of the solid components in the soft magnetic resin composition is, for example, 20% by mass or more and 70% by mass or less, preferably 30% by mass or more and 60% by mass or less, more preferably 35% by mass or more and 50% by mass or less, and even more preferably 40% by mass or more and 45% by mass or less.

[0128] The solid component concentration (volume percentage) of the soft magnetic resin composition is, for example, 5% or more and 50% or less, preferably 5% or more and 30% or less, more preferably 8% or more and 20% or less, even more preferably 10% or more and 15% or less, and especially preferably 11% or more and 14% or less.

[0129] If the solid content concentration of the soft magnetic resin composition is above or below the aforementioned lower limit, the viscosity of the soft magnetic resin composition at rest (viscosity at low shear rates) can be sufficiently ensured, thus suppressing the sedimentation and uneven presence of flattened soft magnetic particles. Furthermore, if the solid content concentration of the soft magnetic resin composition is below or below the aforementioned upper limit, the flowability of flattened soft magnetic particles can be improved (viscosity at high shear rates) when coating with the soft magnetic resin composition, thus enabling stable and efficient continuous coating of the soft magnetic resin composition.

[0130] The soft magnetic resin composition may also contain other additives.

[0131] Other additives include, for example, crosslinking agents, inorganic fillers, and other commercially available or well-known additives.

[0132] The soft magnetic resin composition is prepared by mixing the above-mentioned flat soft magnetic particles, resin components and other additives as needed in the above-mentioned proportions, and then dispersing them in the above-mentioned dispersion medium.

[0133] Shear rate 38.1 s -1 The viscosity (A) of the soft magnetic resin composition is 300 mPa·s or more, preferably 350 mPa·s or more, more preferably 400 mPa·s or more, further preferably 420 mPa·s or more, and especially preferably 450 mPa·s or more. It is also, for example, 1000 mPa·s or less, preferably 900 mPa·s or less, more preferably 800 mPa·s or less, further preferably 750 mPa·s or less, and especially preferably 700 mPa·s or less. Additionally, the shear rate is 38.1 s⁻¹. -1 The viscosity (A) of the soft magnetic resin composition is, for example, 300 mPa·s or more and 1000 mPa·s or less, preferably 350 mPa·s or more and 900 mPa·s or less, more preferably 400 mPa·s or more and 800 mPa·s or less, and even more preferably 420 mPa·s or more and 750 mPa·s or less.

[0134] If the shear rate is 38.1 s -1 If the viscosity (A) of the soft magnetic resin composition is above the aforementioned lower limit, the sedimentation and uneven distribution of flattened soft magnetic particles can be suppressed. Furthermore, if the shear rate is 38.1 s... -1 If the viscosity (A) of the soft magnetic resin composition is below the above-mentioned upper limit, then the soft magnetic resin composition has excellent processability (operability).

[0135] Shear rate 76.6 s -1 The viscosity (B) of the soft magnetic resin composition is 200 mPa·s or more and 800 mPa·s or less, preferably 250 mPa·s or more and 700 mPa·s or less, more preferably 280 mPa·s or more and 600 mPa·s or less, and even more preferably 300 mPa·s or more and 550 mPa·s or less.

[0136] Shear rate 191.5 s -1 The viscosity (C) of the soft magnetic resin composition is 150 mPa·s or more and 500 mPa·s or less, preferably 180 mPa·s or more and 400 mPa·s or less, and more preferably 200 mPa·s or more and 350 mPa·s or less.

[0137] Shear rate 383s-1 The viscosity (D) of the soft magnetic resin composition is 100 mPa·s or more and 400 mPa·s or less, preferably 120 mPa·s or more and 300 mPa·s or less, and more preferably 140 mPa·s or more and 250 mPa·s or less.

[0138] If the shear rate is 383s -1 If the viscosity (D) of the soft magnetic resin composition is above the aforementioned lower limit, then when coating the soft magnetic resin composition, the settling of flattened soft magnetic particles within the soft magnetic resin composition can be suppressed, thus enabling stable coating of the soft magnetic resin composition. Furthermore, if the shear rate is 383 s... -1 If the viscosity (D) of the soft magnetic resin composition is below the above-mentioned upper limit, the flowability of the flat soft magnetic particles can be improved when coating the soft magnetic resin composition. Therefore, the soft magnetic resin composition can be continuously coated stably and efficiently.

[0139] In the following description, the shear rate is 38.1 s. -1 The viscosity (A) of the soft magnetic resin composition is 76.6 s⁻¹ relative to the shear rate. -1 191.5s -1 and 383s -1 The viscosity ratios (B to D) of the soft magnetic resin compositions are expressed as A / B, A / C, and A / D, respectively.

[0140] As for A / B, it is, for example, 1.20 or more and 2.00 or less, preferably 1.25 or more and 1.80 or less, and more preferably 1.25 or more and 1.40 or less.

[0141] As for the A / C ratio, it is 1.70 or higher, preferably 1.75 or higher, more preferably 1.80 or higher, even more preferably 1.85 or higher, particularly preferably 2.00 or higher. Alternatively, it is, for example, 3.00 or lower, preferably 2.50 or lower, more preferably 2.30 or lower, and even more preferably 2.10 or lower. Furthermore, as for the A / C ratio, it is, for example, 1.70 or higher and 3.00 or lower, preferably 1.75 or higher and 2.50 or lower, more preferably 1.80 or higher and 2.30 or lower, and even more preferably 1.85 or higher and 2.10 or lower.

[0142] If A / C is above the lower limit mentioned above, the sedimentation and unevenness of flat soft magnetic particles can be suppressed. Furthermore, when coating the soft magnetic resin composition, the flowability of the flat soft magnetic particles can be improved. Therefore, the soft magnetic resin composition can be continuously coated stably and efficiently.

[0143] The A / D ratio is, for example, 2.00 to 5.00, preferably 2.30 to 4.00, more preferably 2.50 to 3.50, even more preferably 2.55 to 3.30, and especially preferably 2.55 to 3.10.

[0144] It should be noted that the above viscosity can be determined using the methods described in JIS Z 8803 and ISO 3219 (JIS K 7117-2). Specifically, it can be measured using a conical-plate rotational viscometer. The conical-plate rotational viscometer is a viscometer described in JIS Z 8803 and ISO 3219 (JIS K 7117-2), and its wetted part consists of a conical rotor (conical rotor) and a plate. The sample is filled between the cone and the plate.

[0145] Specifically, the viscosity described above can be determined by the method described in the examples below.

[0146] Furthermore, the shear rate, also known as the shear velocity, is determined in the conical-plate rotational viscometer described above using the following formula relating the shear rate (D) to the rotational speed (N). However, the cone angle (φ) varies depending on the measuring device.

[0147] D=2πN / 60φ

[0148] D: Shear rate (s) -1 )

[0149] N: Rotational speed of the conical rotor (rpm)

[0150] φ: Cone angle

[0151] 2. Soft magnetic thin film

[0152] The soft magnetic film disclosed herein is formed, for example, by thermosetting a soft magnetic resin composition. In other words, the soft magnetic film is a cured product of the soft magnetic resin composition.

[0153] The soft magnetic film is, for example, in a fully cured state.

[0154] It should be noted that a fully cured state refers to a state in which there is no exothermic reaction accompanying the curing reaction, for example, in differential scanning calorimetry.

[0155] Soft magnetic thin films are, for example, thin film shapes (including sheet shapes).

[0156] The thickness of the soft magnetic film is, for example, 5 μm or more and 500 μm or less, preferably 50 μm or more and 250 μm or less.

[0157] In the soft magnetic film, the volume percentage of flat soft magnetic particles (excluding voids) is, for example, 40% or more and 80% or less, preferably 45% or more and 70% or less, more preferably 50% or more and 60% or less, and even more preferably 53% or more and 57% or less.

[0158] In soft magnetic films, if the volume ratio of flat soft magnetic particles is within the above range, the soft magnetic film has excellent permeability.

[0159] It should be noted that the volume ratio of flat, soft magnetic particles can be determined, for example, by the Archimedes method.

[0160] For example, a soft magnetic thin film may have flattened soft magnetic particles dispersed within its two-dimensional plane. Specifically, the flattened soft magnetic particles are oriented along the plane of the soft magnetic film with their length direction (orthogonal to the thickness direction) aligned with the surface direction of the film. Therefore, the magnetic properties of the soft magnetic thin film are further enhanced.

[0161] In the soft magnetic film (cured product of soft magnetic resin composition), the magnetic permeability at a frequency of 10 MHz is, for example, 40 or more, preferably 45 or more, more preferably 47 or more, and even more preferably 49 or more.

[0162] It should be noted that the permeability at a frequency of 10MHz can be determined, for example, by measuring the impedance at 10MHz using an impedance analyzer (E4991 Bimpedance Analyzer, manufactured by KEYSIGHT).

[0163] Soft magnetic films can be used, for example, to form a single-layer structure consisting only of a single layer of soft magnetic film, a multilayer structure in which soft magnetic films are stacked on one or both sides of a core material, or a multilayer structure in which release liner is stacked on one or both sides of a soft magnetic film.

[0164] <Method for manufacturing soft magnetic films (method of using soft magnetic resin compositions)>

[0165] The method for manufacturing a soft magnetic film disclosed herein includes, for example, the following steps: a coating step in which the soft magnetic resin composition is continuously coated onto a substrate at a coating speed of 5 m / min or more; a drying step in which the dispersion medium contained in the soft magnetic resin composition coated onto the substrate is dried to obtain a soft magnetic film before complete curing; and a curing step in which the soft magnetic film before complete curing is thermally cured.

[0166] (Coating process)

[0167] In the coating process, the soft magnetic resin composition is continuously coated onto the surface of the substrate at a coating speed of 5 m / min or more.

[0168] Examples of substrates include, for example, release liner and core material.

[0169] Examples of release liner materials include polyethylene terephthalate (PET) film, polyethylene film, polypropylene film, and paper, with PET film being a preferred example. The surface of the release liner is preferably treated with a fluorinated release agent, a long-chain alkyl acrylate release agent, or a silicone release agent for mold release.

[0170] Examples of core materials include plastic films (such as polyimide films, polyester films, polyethylene terephthalate films, polyethylene naphthalate films, and polycarbonate films), metal films (such as aluminum foil), glass substrates, silicon substrates, and resin substrates reinforced with glass fibers or plastic nonwoven fibers.

[0171] The average thickness of the substrate is, for example, greater than 1 μm and less than 500 μm.

[0172] As for the coating method, there are no particular limitations as long as it is a continuous coating method, but coating methods with excellent mass production performance for strip coating are preferred. Specifically, examples of coating methods include coating using a roller coater, and in particular coating using a comma coater.

[0173] The coating gap is, for example, 100 μm or more and 1000 μm or less, preferably 150 μm or more and 800 μm or less, more preferably 200 μm or more and 700 μm or less, even more preferably 250 μm or more and 600 μm or less, and especially preferably 300 μm or more and 500 μm or less.

[0174] It should be noted that when using a comma-shaped coating machine, the coating gap refers to the distance between the coating surface of the substrate and the blade roller. The shear rate can be expressed as the ratio of the coating gap to the coating speed. Therefore, when coating at the same coating speed, reducing the coating gap will impart a higher shear rate to the soft magnetic resin composition.

[0175] If the coating gap is set too small, depending on the particle size of the flat, soft magnetic particles contained in the soft magnetic resin composition, the particles may sometimes get stuck in the coating gap, forming coating streaks. That is, if the coating gap is above the aforementioned lower limit value, the shear rate can be ensured and coating streaks caused by particle jamming can be suppressed.

[0176] The coating speed is, for example, 5 m / min or more and 50 m / min or less, preferably 6 m / min or more and 50 m / min or less, more preferably 7 m / min or more and 30 m / min or less, and even more preferably 8 m / min or more and 20 m / min or less.

[0177] As described above, with a constant coating gap, a higher coating speed is required to achieve a high shear rate. However, if the coating speed is too fast, the drying oven length needs to be increased based on the drying time in the subsequent drying process, resulting in a large-scale apparatus. That is, if the coating speed is below the aforementioned upper limit, space can be saved while ensuring the shear rate.

[0178] The coating speed mentioned above refers to the coating speed when the soft magnetic resin composition is being coated stably. In other words, the coating speed at the beginning and end of the coating process is not limited to this.

[0179] Specifically, at the beginning of the coating process, it is preferable to increase the coating speed continuously or in stages until the coating speed reaches 5 m / min or more.

[0180] At the start of the coating process, if the coating speed is increased continuously or in stages, uneven coating at the ends can be suppressed. More specifically, by gradually increasing the coating speed continuously or in stages at the start of coating, abrupt changes in the viscosity of the soft magnetic resin composition can be suppressed, thus suppressing uneven coating caused by liquid drying.

[0181] In addition, at the end of the coating process, it is preferable to reduce the coating speed continuously or in stages.

[0182] (Drying process)

[0183] In the drying process, the dispersion medium contained in the soft magnetic resin composition coated on the substrate is dried to obtain a soft magnetic film before complete curing.

[0184] The drying temperature is, for example, above 70°C and below 160°C.

[0185] The drying time is, for example, more than 1 minute and less than 5 minutes.

[0186] This allows the dispersion medium contained in the coated soft magnetic resin composition to be dried, resulting in a film before complete curing.

[0187] The soft magnetic film before complete curing refers to the soft magnetic film in its state before complete curing at room temperature (e.g., 25°C), and is a soft magnetic adhesive film with good adhesion. It should be noted that the soft magnetic film before complete curing refers to a state between, for example, the uncured soft magnetic resin composition at room temperature (e.g., 25°C) and the fully cured soft magnetic film, a state in which curing has been slightly completed.

[0188] The average thickness of the soft magnetic film before complete curing is, for example, 5 μm or more and 500 μm or less, preferably 5 μm or more and 300 μm or less, more preferably 5 μm or more and 200 μm or less, further preferably 50 μm or more and 150 μm or less, and especially preferably 50 μm or more and 100 μm or less.

[0189] (Curing process)

[0190] In the curing process, the soft magnetic film before it is fully cured is thermally cured to obtain a soft magnetic film (a soft magnetic film in a fully cured state).

[0191] Specifically, multiple soft magnetic films obtained during the drying process but before full curing are prepared, and these films are then hot-pressed along their thickness direction. This process cures the soft magnetic films, resulting in a soft magnetic film. In other words, a soft magnetic film refers to a soft magnetic film in its fully cured state.

[0192] Furthermore, the hot pressing described above is not limited to hot pressing only the soft magnetic film before it is fully cured. Specifically, as detailed later, the soft magnetic film before it is fully cured can also be hot-pressed together with the wiring. This allows the soft magnetic film before it is fully cured to be cured, resulting in an inductor having both the soft magnetic film and the wiring.

[0193] Hot pressing can be carried out using known pressing machines, such as parallel plate presses.

[0194] The number of layers of the semi-cured soft magnetic film can be adjusted according to the desired film thickness, for example, more than 2 layers and less than 20 layers, preferably more than 2 layers and less than 5 layers.

[0195] The hot pressing temperature is, for example, above 80°C and below 200°C, preferably above 100°C and below 175°C.

[0196] The hot pressing time is, for example, 0.1 hours or more and 24 hours or less, preferably 0.2 hours or more and 3 hours or less, and more preferably 0.2 hours or more and 2 hours or less.

[0197] The pressure of hot pressing is, for example, 10 MPa or more and 500 MPa or less, preferably 20 MPa or more and 200 MPa or less.

[0198] Therefore, in soft magnetic films, the permeability of flat soft magnetic particles and the thin-film structure of soft magnetic films can be improved.

[0199] Thus, a soft magnetic film in a fully cured state is obtained.

[0200] It should be noted that in the above-mentioned method for manufacturing soft magnetic films, multiple soft magnetic films before complete curing are stacked and hot-pressed, but for example, a single soft magnetic film before complete curing (single layer) can also be hot-pressed.

[0201] Such soft magnetic films can be used, for example, in inductors or magnetic wiring circuit boards.

[0202] 3. Inductor

[0203] Reference Figure 1 and Figure 2 An embodiment of the inductor disclosed herein will be described.

[0204] The inductor 10, for example, includes a soft magnetic thin film 1 and wiring 2. Specifically, such as... Figure 1 As shown, the inductor 10 includes, for example, wiring 2 and a soft magnetic film 1 covering the entire outer peripheral surface of wiring 2.

[0205] The soft magnetic film 1 comprises a resin component 3 and flattened soft magnetic particles 4. The flattened soft magnetic particles 4 are dispersed, for example, along the in-plane direction of the soft magnetic film 1. It should be noted that the soft magnetic resin composition may contain other additives besides the resin component 3 and the flattened soft magnetic particles 4, which are not shown in the figure.

[0206] The wiring 2 can be single or multiple. In the case where the inductor has multiple wiring 2, one wiring 2 and other wiring 2 adjacent to one wiring 2 in the width direction (first direction) orthogonal to the thickness direction are arranged at intervals in the width direction (first direction).

[0207] Wiring 2 extends in a strip shape in a second direction orthogonal to both the thickness and width directions, and its top view shape is not particularly limited. Examples of top view shapes for wiring 2 include a roughly straight shape and a roughly U-shaped shape.

[0208] The cross-sectional shape of wiring 2 is not particularly limited; for example, it can be a roughly circular cross-section or a roughly rectangular cross-section. Figure 1 As shown, the cross-sectional shape of wiring 2 is preferably an approximately circular cross-section.

[0209] Wiring 2, for example, includes a conductor 5 and an insulating layer 6 covering the conductor 5.

[0210] The conductor 5 extends in a long strip in the second direction, and its top view shape is the same as that of the wiring 2 described above. Specifically, the top view shape of the conductor 5 can be exemplified by, for example, a roughly straight shape and a roughly U-shaped shape.

[0211] Furthermore, the cross-sectional shape of the conductor 5 is the same as that of the wiring 2 described above. The conductor 5 preferably has a generally circular cross-sectional shape that shares a central axis with the wiring 2.

[0212] The material of the conductor 5 is, for example, a metallic conductor such as copper, silver, gold, aluminum, nickel, or their alloys, with copper being a preferred example. The conductor 5 can be a single-layer structure or a multi-layer structure in which the surface of the core conductor (e.g., copper) is plated with a coating (e.g., nickel).

[0213] The radius of the conductor 5 is, for example, 25 μm or more and 2000 μm or less, preferably 50 μm or more and 200 μm or less.

[0214] Insulation layer 6 is used to protect conductor 5 from chemical reagents and water and to prevent short circuits in conductor 5. Insulation layer 6 is configured to cover the entire outer circumference of conductor 5.

[0215] The insulating layer 6, for example, has a roughly annular cross-sectional shape that shares a central axis with the wiring 2.

[0216] Materials used as insulating layer 6 include, for example, polyvinyl alcohol formaldehyde, polyester, polyesterimide, polyamide (including nylon), polyimide, polyamideimide, polyurethane, and other insulating resins. They can be used alone or in combination of two or more.

[0217] The insulating layer 6 can be composed of a single layer or multiple layers.

[0218] The thickness of the insulating layer 6 is approximately uniform in the radial direction of the wiring 2 at any position in the circumferential direction, for example, 1 μm or more and 100 μm or less, preferably 3 μm or more and 50 μm or less.

[0219] <Inductor Manufacturing Methods>

[0220] As such an inductor 10, for example, Figure 2 A~ Figure 2 As shown in C, it is manufactured by a manufacturing method comprising the following steps: a preparation step, preparing a soft magnetic film 1' and wiring 2 before complete curing; a configuration step, configuring the soft magnetic film 1' and wiring 2 before complete curing; and a curing step, curing the soft magnetic film 1' before complete curing.

[0221] First, in the preparation process, for example, the soft magnetic film 1' and wiring 2 are prepared before complete curing. Specifically, in the preparation process, such as... Figure 2 As shown in Figure A, wiring 2 is prepared on one side of a soft magnetic film 1' before complete curing, and another soft magnetic film 1' before complete curing is prepared on one side of the wiring 2 before complete curing.

[0222] It should be noted that the soft magnetic film 1' before complete curing can be used alone or as... Figure 2 As shown in Figure A, multiple layers are used.

[0223] The soft magnetic film 1' before complete curing contains resin component 3 and flattened soft magnetic particles 4. The flattened soft magnetic particles 4 are dispersed, for example, in the two-dimensional plane of the soft magnetic film 1' before complete curing. It should be noted that the soft magnetic resin composition may contain other additives besides resin component 3 and flattened soft magnetic particles 4, which are not shown in the figure.

[0224] Next, as Figure 2 As shown in Figure B, in the configuration step, for example, a soft magnetic film 1' and wiring 2 are configured before complete curing. Specifically, in the configuration step, the soft magnetic film 1' before complete curing is configured such that wiring 2 is included and the entire outer peripheral surface of wiring 2 is covered.

[0225] As a method of configuring the fully cured soft magnetic film 1' in a manner that covers the entire outer peripheral surface of the wiring 2, for example, one fully cured soft magnetic film 1' and another fully cured soft magnetic film 1' are pressed together in a manner that clamps the wiring 2, thereby deforming one fully cured soft magnetic film 1' and the other fully cured soft magnetic film 1', so that the wiring 2 is embedded.

[0226] Thus, two soft magnetic films 1' before complete curing can be configured to cover the entire outer periphery of the wiring 2.

[0227] Next, in the curing process, such as Figure 2 As shown in Figure C, two uncured soft magnetic films 1' are heated to cure, thus forming a soft magnetic film 1. It should be noted that, through curing, the contact interface between the two uncured soft magnetic films 1' disappears, and the two uncured soft magnetic films 1' form a single soft magnetic film 1.

[0228] It should be noted that during the preparation process, heating can also be performed simultaneously with pressing to solidify the material and form a soft magnetic film 1. In this case, the curing step can be omitted.

[0229] Thus, inductor 10 is obtained.

[0230] (Example of an inductor)

[0231] The inductor 10 described above only has wiring 2 and soft magnetic film 1, but is not limited to this.

[0232] Specifically, although not shown in the figure, an adhesive layer may be provided between the wiring 2 and the soft magnetic film 1.

[0233] It should be noted that the adhesive used for the adhesive layer can be any known adhesive commonly used as an adhesive for the inductor component 10, without any particular limitation. Examples include epoxy adhesives, polyimide adhesives, acrylic adhesives, etc.

[0234] The coating thickness of the adhesive is, for example, 10 μm or more and 100 μm or less.

[0235] Although a variation of the inductor 10 described above is not shown, it can be manufactured using a soft magnetic film 1, wiring 2, and adhesive.

[0236] Specifically, in the preparation process, wiring 2 is prepared on the thickness direction side (adhesive coating side) of a soft magnetic film 1 coated with adhesive on one side of the thickness direction, and another soft magnetic film 1 coated with adhesive on the other side of the thickness direction is prepared on the thickness direction side of wiring 2.

[0237] Next, in the configuration process, one soft magnetic film 1 and another soft magnetic film 1 are pressed in a way that clamps the wiring 2, thereby embedding the wiring 2 by using one soft magnetic film 1 and another soft magnetic film 1 to clamp the wiring 2 with an adhesive.

[0238] Thus, the soft magnetic film 1 can be configured with an adhesive in a manner that covers the entire outer periphery of the wiring 2.

[0239] When using soft magnetic film 1, the curing process is omitted.

[0240] Thus, inductor 10 is obtained.

[0241] 4. Magnetic wiring circuit board

[0242] Reference Figure 3 An embodiment of a magnetic wiring circuit board using the soft magnetic thin film of this disclosure will be described.

[0243] The magnetic wiring circuit board 11 includes, for example, a soft magnetic thin film 1 and a circuit board 7.

[0244] Specifically, such as Figure 3 As shown, the magnetic wiring circuit board 11, for example, has a circuit board 7 and a soft magnetic film 1 sequentially arranged in the thickness direction (stack direction). That is, the magnetic wiring circuit board 11 has the soft magnetic film 1 on one side of the circuit board 7 in the thickness direction.

[0245] <Manufacturing Method of Magnetic Wiring Circuit Board>

[0246] Such a magnetic wiring circuit board 11 can be manufactured, for example, by a manufacturing method including a preparation step of preparing a soft magnetic film 1' before complete curing and a circuit board 7, a lamination step of laminating the soft magnetic film 1' before complete curing on the circuit board 7, and a curing step of curing the soft magnetic film 1' before complete curing.

[0247] First, prepare the soft magnetic film 1' before it is fully cured and the circuit board 7. Specifically, prepare the soft magnetic film 1' before it is fully cured and the circuit board 7 on which wiring patterns 8 are formed on the surface of the substrate 9.

[0248] In addition, the soft magnetic film 1' before complete curing can be used alone or in multiples.

[0249] The soft magnetic film 1' before complete curing comprises resin component 3 and flattened soft magnetic particles 4. The flattened soft magnetic particles 4 are arranged, for example, in the in-plane direction of the soft magnetic film 1' before complete curing. It should be noted that the soft magnetic resin composition may contain other additives besides resin component 3 and flattened soft magnetic particles 4.

[0250] The circuit board 7, for example, is a circuit board used in electromagnetic induction, and a wiring pattern 8 such as a ring coil is formed on one side of the substrate 9 in the thickness direction.

[0251] Wiring pattern 8 is made of metal materials such as copper and formed by semi-additive or subtractive methods.

[0252] The substrate 9 is formed of an insulating material, for example. Examples of substrates 9 formed of insulating materials include glass epoxy boards, glass substrates, polyethylene terephthalate (PET) substrates, ceramic substrates, and polyimide substrates.

[0253] Next, in the lamination process, for example, a soft magnetic film 1' before complete curing is laminated onto one side of the circuit substrate 7 in the thickness direction. Specifically, the soft magnetic film 1' before complete curing is brought into contact with one side of the circuit substrate 7 in the thickness direction.

[0254] It should be noted that the soft magnetic film 1' before it is fully cured can also be pressed from one side of the thickness direction of the circuit board 7 to the other side of the thickness direction.

[0255] Next, in the curing process, the soft magnetic film 1' before it is fully cured is heated to cure it, thus forming the soft magnetic film 1.

[0256] It should be noted that during the lamination process, heating can be performed simultaneously with pressing to solidify the material and produce a soft magnetic film 1. In this case, the curing step can be omitted.

[0257] Thus, the magnetic wiring circuit board 11 is obtained.

[0258] (Modified example of magnetic wiring circuit board)

[0259] The magnetic wiring circuit board 11 described above has a circuit board 7 and a soft magnetic film 1 sequentially in the thickness direction (stack direction), but is not limited thereto.

[0260] Specifically, although not illustrated, the magnetic wiring circuit board may sequentially include a circuit board 7, an adhesive layer, and a soft magnetic film 1 in the thickness direction (stack direction).

[0261] [use]

[0262] Such a soft magnetic film 1 can be used in antennas, coils, etc., of electronic devices. In addition, as mentioned above, the soft magnetic film 1 can be used in inductors 10, and can be mounted in electronic devices, etc., as a passive component such as a voltage conversion component.

[0263] Example

[0264] The following examples and comparative examples further illustrate this disclosure in detail. It should be noted that this disclosure is not limited to the examples and comparative examples in any way. In addition, the specific numerical values ​​such as mixing ratios (including ratios), physical property values, and parameters used in the following description can be replaced with the upper limit (defined as "below" or "less than") or lower limit (defined as "above" or "more than") of the mixing ratios (including ratios), physical property values, and parameters recorded in the above "Detailed Embodiments".

[0265] <Detailed information on ingredients>

[0266] The trade names and abbreviations of the ingredients used in each embodiment and comparative example are described in detail.

[0267] Fe-Si alloy: coercivity 500 A / m, density 7.17 g / cm³ 3

[0268] o-Cresol phenolic resin for varnish type: trade name "EPICLON N665-EXPS", manufactured by DIC, epoxy equivalent 200 g / eq, density 1.19 g / cm³ 3

[0269] Acrylic polymer: Trade name "Teisan Resin SG-70LN", manufactured by Nagase ChemteX, solids content 12.5% ​​by mass (methyl ethyl ketone solution), density 1.0 g / cm³ 3

[0270] Biphenylaryl phenolic resin: trade name "MEHC-7851SS", manufactured by Meiwa Chemical Co., Ltd., hydroxyl equivalent 203 g / eq, density 1.19 g / cm³. 3

[0271] Imidazole compound: Trade name "2PHZ-PW", manufactured by Shikoku Chemical Co., Ltd., solid content concentration 10.0% by mass (methyl ethyl ketone solution), density 1.33 g / cm³ 3

[0272] Example 1

[0273] <Preparation of Soft Magnetic Particles>

[0274] Fe-Si alloy, used as a soft magnetic material, is processed into spherical soft magnetic particles by gas atomization, and these particles are then classified. Next, a predetermined amount of the classified soft magnetic particles is fed into a grinding mill. Alcohol and powder media are also added to the grinding mill. The spherical soft magnetic particles are processed into flat shapes using the grinding mill, and the resulting coarse and refined flat soft magnetic particles are classified using a mesh, thereby obtaining the flat soft magnetic particles of Example 1 with the desired particle size (particle size distribution).

[0275] The particle sizes D10, D50, and D90 of the flat, soft magnetic particles of Example 1 were determined using a laser diffraction particle size distribution analyzer (Beckman Coulter, LS 13 320). The results are shown in Table 3.

[0276] <Preparation of Soft Magnetic Resin Compositions>

[0277] Next, a soft magnetic resin composition was prepared based on the composition shown in Preparation Example (I) described in Table 1. Specifically, 380 parts by weight of the flat soft magnetic particles of Example 1, 12.7 parts by weight of o-cresol phenolic varnish-type epoxy resin as epoxy resin, 163.5 parts by weight of acrylate polymer solution as acrylic resin (20.4 parts by weight of solids), 12.7 parts by weight of biphenyl aralkyl phenolic resin as curing agent, and 4.6 parts by weight of imidazole compound solution as curing accelerator (0.5 parts by weight of solids) were mixed.

[0278] Next, 452.9 parts by mass of methyl ethyl ketone as a dispersion medium were added to the above mixture, thereby preparing a soft magnetic resin composition with a solid content of 11.3% by volume.

[0279] It should be noted that the mass (g) and volume (cm³) of each component of the soft magnetic resin composition in Preparation Example (I) are specified. 3 ), solid component mass (g) and solid component volume (cm³) 3The contents of the resin component (other than the flattened soft magnetic particles) in the solid components of the soft magnetic resin composition in Preparation Example (I) are shown in Table 1. In addition, the contents of the resin component (other than the flattened soft magnetic particles) in the solid components of the soft magnetic resin composition (mass % and volume %), the contents of the flattened soft magnetic particles in the solid components of the soft magnetic resin composition (mass % and volume %), the concentration of the solid components of the soft magnetic resin composition (mass % and volume %), and the contents of the flattened soft magnetic particles in the soft magnetic resin composition (mass % and volume %) are shown in Table 2.

[0280] Example 2 and Example 3

[0281] Except for changing the processing time using the grinding mill, flattened soft magnetic particles of Examples 2 and 3 were obtained in the same manner as in Example 1. The particle sizes D10, D50, and D90 of the soft magnetic particles of Examples 2 and 3 were measured in the same manner as in Example 1. The results are shown in Table 3.

[0282] In addition, except for using the flattened soft magnetic particles of Examples 2 and 3, the soft magnetic resin compositions of Examples 2 and 3 were prepared in the same manner as in Example 1.

[0283] Example 4

[0284] By changing the processing time of the grinding mill and the sieve aperture of the grading screen, the same flat, soft magnetic particles as in Example 1 were obtained in Example 4. The particle sizes D10, D50, and D90 of the soft magnetic particles of Example 4 were measured in the same manner as in Example 1. The results are shown in Table 3.

[0285] In addition, except that the flat soft magnetic particles of Example 4 were used, the soft magnetic resin composition of Example 4 was prepared in the same manner as in Example 1.

[0286] [Comparative Example 1]

[0287] In the processing using a grinding mill, the specified throughput of the raw material powder, the processing time, and the sieve aperture of the subsequent grading screen were changed. Otherwise, the same flattened soft magnetic particles as in Example 1 were obtained. The particle sizes D10, D50, and D90 of the soft magnetic particles of Comparative Example 1 were measured in the same manner as in Example 1. The results are shown in Table 3.

[0288] In addition, except that the flat soft magnetic particles of Comparative Example 1 were used, the soft magnetic resin composition of Comparative Example 1 was prepared in the same manner as in Example 1.

[0289] [Comparative Example 2]

[0290] Using the flattened soft magnetic particles of Example 4, and based on the composition shown in Preparation Example (II) in Table 1, the amount of dispersion medium was varied to prepare a soft magnetic resin composition. Otherwise, the soft magnetic resin composition of Comparative Example 2 was prepared in the same manner as in Example 1. It should be noted that the solid content concentration of the soft magnetic resin composition of Comparative Example 2 was 10.3% by volume.

[0291] In addition, the mass (g) and volume (cm³) of each component of the soft magnetic resin composition in Preparation Example (II) were measured. 3 ), solid component mass (g) and solid component volume (cm³) 3 The contents of the resin component (other than the flattened soft magnetic particles) in the solid components of the soft magnetic resin composition in Preparation Example (II) are shown in Table 1. Furthermore, the contents of the resin component (other than the flattened soft magnetic particles) in the solid components of the soft magnetic resin composition (mass % and volume %), the contents of the flattened soft magnetic particles in the solid components of the soft magnetic resin composition (mass % and volume %), the concentration of the solid components of the soft magnetic resin composition (mass % and volume %), and the contents of the flattened soft magnetic particles in the soft magnetic resin composition (mass % and volume %) are shown in Table 2.

[0292] <Evaluation>

[0293] [Viscosity]

[0294] The viscosity of the soft magnetic resin compositions of each example and comparative example was determined at 25°C. In the viscosity determination, a viscometer (trade name "RE-85", manufactured by Toki Sangyo Co., Ltd.) and a conical rotor (trade name "1°34'×R24", 1.1 ml, shear rate: 3.83 N (1 / s), manufactured by Toki Sangyo Co., Ltd.) were used to measure the viscosity at various shear rates. It should be noted that the rotational speed of the conical rotor was determined at four points: 10 rpm, 20 rpm, 50 rpm, and 100 rpm. However, since the rotational speed N (rpm) of the conical rotor used is related to the shear rate (i.e., the shear velocity) by 3.83 N (s), the viscosity was not determined by these parameters. -1 Therefore, the shear rate at each measurement point is 38.3 (s) at 10 rpm. -1 At 20 rpm, it is 76.6 (s). -1 At 50 rpm, it is 191.5 (s). -1 ), and 383 (s) at 100 rpm. -1 The viscosities at each shear rate were denoted as A to D. The results are shown in Table 3. Furthermore, the relationship between shear rate and viscosity is presented in... Figure 4 The chart.

[0295] In addition, the ratios of viscosity A to viscosities B through D (A / B, A / C, and A / D) were calculated. The results are shown in Table 3.

[0296] [Continuous coating capability]

[0297] The soft magnetic resin compositions of each example and comparative example were continuously coated onto a release liner (average thickness: 50 μm) made of polyethylene terephthalate film after silicone release treatment using a comma-type coating machine. The coating speed was 10 m / min, and the coating gap was 350 μm. Regarding continuous coating performance, the appearance of the soft magnetic resin compositions on the film was evaluated according to the following criteria. The results are shown in Table 3. It should be noted that the appearance of each soft magnetic resin composition on the film showed almost no change between the immediate coating state and the dried state.

[0298] {Benchmark}

[0299] Good: It can be evenly coated onto a film.

[0300] Poor: Cannot be coated onto the film, or cannot be coated evenly onto the film (streaks, peeling).

[0301] [Permeability]

[0302] The soft magnetic resin compositions of each embodiment and comparative example were continuously coated onto a release liner (average thickness: 50 μm) made of polyethylene terephthalate film after silicone release treatment using a comma-type coating machine, and then dried at 110°C for 2 minutes. This produced a soft magnetic film laminated to the release liner before complete curing (average thickness of the soft magnetic film before complete curing only: 140 μm). Four sheets of this soft magnetic film before complete curing were manufactured and laminated (excluding the release liner). The four laminated soft magnetic films before complete curing were hot-pressed at 9 MPa, 170°C, and 15 minutes to produce a soft magnetic film with a thickness of 150 μm.

[0303] Next, the impedance at 10 MHz was measured using an impedance analyzer (E4991B Impedance Analyzer, manufactured by KEYSIGHT Corporation), thereby determining the permeability of the soft magnetic films formed from the soft magnetic resin compositions of each embodiment and comparative example. The results are shown in Table 3.

[0304] [Table 1]

[0305]

[0306] [Table 2]

[0307]

[0308] [Table 3]

[0309]

[0310] It should be noted that the above invention is provided as an example of the implementation of this disclosure, but it is merely an example and should not be interpreted restrictively. Modifications of this disclosure that are apparent to those skilled in the art are included in the foregoing claims.

[0311] Industrial availability

[0312] The soft magnetic film formed from the soft magnetic resin composition disclosed herein is suitable for use in antennas and coils in electronic devices. Furthermore, such a soft magnetic film can be used in inductors and mounted in electronic devices as passive components such as voltage conversion devices. Moreover, such a soft magnetic film can also be used in magnetic wiring circuit boards.

[0313] Explanation of reference numerals in the attached figures

[0314] 1. Soft magnetic thin film

[0315] 2. Wiring

[0316] 3. Resin composition

[0317] 4. Flat, soft magnetic particles

[0318] 10 Inductors

Claims

1. A soft magnetic resin composition comprising a solid component and a dispersion medium, said solid component comprising flattened soft magnetic particles and a resin component. The shear rate of the soft magnetic resin composition is 38.1 s. -1 The viscosity (A) is above 300 mPa·s. The shear rate of the soft magnetic resin composition is 38.1 s. -1 The viscosity (A) at the specified shear rate is 191.5 s⁻¹. -1 The viscosity (C) ratio (A / C) is 1.70 or higher.

2. The soft magnetic resin composition according to claim 1, wherein, The cumulative value of the volume reference from the smallest particle size side of the flat soft magnetic particles is such that 90% of the particle size (D90) is 80 μm or more and 130 μm or less.

3. The soft magnetic resin composition according to claim 1, wherein, The cumulative value of the volume reference from the smallest particle size side of the flat soft magnetic particles is 50% of the particle size (D50) which is 30 μm or more and 50 μm or less.

4. The soft magnetic resin composition according to claim 1, wherein, The cumulative value of the volume reference from the smallest particle size side of the flat soft magnetic particles is 10% of the particle size (D10) of 5 μm or more.

5. The soft magnetic resin composition according to claim 1, wherein, The solid content concentration of the soft magnetic resin composition is 11% by volume or more and 14% by volume or less.

6. The soft magnetic resin composition according to claim 1, wherein, The resin composition includes thermosetting resin components and thermoplastic resin components.

7. The soft magnetic resin composition according to claim 6, wherein, The thermosetting resin component includes epoxy resin. The thermoplastic resin component includes acrylic resins.

8. The soft magnetic resin composition according to claim 7, wherein, The thermosetting resin component also includes a curing agent and a curing accelerator.

9. The soft magnetic resin composition according to claim 1, wherein, The proportion of the flattened soft magnetic particles in the solid component of the soft magnetic resin composition is 45% by volume or more and 70% by volume or less.

10. The soft magnetic resin composition according to claim 1, wherein, The cured soft magnetic resin composition has a permeability of 40 or higher at a frequency of 10 MHz.

11. A soft magnetic film, which is a cured product of the soft magnetic resin composition according to any one of claims 1 to 10.

12. An inductor comprising the soft magnetic thin film and wiring as described in claim 11.

13. A method for manufacturing a soft magnetic thin film, comprising the following steps: In the coating process, the soft magnetic resin composition according to any one of claims 1 to 10 is continuously coated onto the substrate at a coating speed of 5 m / min or more; A drying process is performed to dry the dispersion medium contained in the soft magnetic resin composition coated on the substrate, resulting in a soft magnetic film before complete curing; and The curing process thermally cures the soft magnetic film before it is fully cured.

14. The method for manufacturing a soft magnetic thin film according to claim 13, wherein, In the coating process, the coating speed is increased continuously or in stages until the coating speed reaches more than 5 m / min.

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