Resin composition

Abstract

To provide a resin composition that can produce a cured product with improved specific magnetic permeability and magnetic loss.SOLUTION: A resin composition comprising: (A) a Ni-containing iron alloy-based magnetic powder; (B) a Mn-containing ferrite-based magnetic powder; and (C) a thermosetting resin, the component (A) containing an Fe-Ni-Cr-based alloy magnetic powder, the component (B) containing or not containing a Zn-containing ferrite-based magnetic power, and the mass ratio ((Mn+Zn) / Fe) of the total amount of Mn and Zn to an amount of Fe in the entire magnetic powder contained in the component (A) and the component (B) being 0.055 or more and 0.16 or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a resin composition, a cured product using the resin composition, a magnetic paste, a resin sheet, a circuit board, and an inductor board.

Background Art

[0002] As a core material for inductor components, a cured product obtained by curing a resin composition containing magnetic powder may be used. As the magnetic powder, FeNi alloy powder may be used (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Conventionally, it has been common to mount independent inductor components on the substrate of a semiconductor device. However, in recent years, a method of forming a coil by a conductor pattern on the substrate and providing an inductor element inside the substrate has been sometimes performed. For further improvement in the performance of inductor elements used for such applications, it is required to further improve the magnetic properties of the core material. Specifically, development of a technology capable of realizing a core material having a high relative permeability and low magnetic loss by a cured product of a resin composition containing magnetic powder is required.

[0005] The present invention has been devised in view of the above problems, and an object thereof is to provide a resin composition capable of obtaining a cured product with improved relative permeability and magnetic loss; a cured product of the resin composition; a magnetic paste and a resin sheet containing the resin composition; and a circuit board and an inductor board containing the cured product of the resin composition.

Means for Solving the Problems

[0006] The present inventors have intensively studied to solve the above problems. As a result, the present inventors have found that a resin composition containing in combination (A) an iron alloy-based magnetic powder containing Ni, (B) a ferrite-based magnetic powder containing Mn, and (C) a thermosetting resin, wherein the component (A) contains an Fe-Ni-Cr alloy magnetic powder, and the component (B) contains or does not contain a ferrite-based magnetic powder containing Zn, and a resin composition in which the mass ratio ((Mn + Zn) / Fe) of the total amount of Mn and Zn to the amount of Fe in the total magnetic powder contained in the components (A) and (B) satisfies a specific numerical range can solve the above problems, and completed the present invention.

[0007] That is, the present invention includes the following. <1> (A) A resin composition containing an iron alloy-based magnetic powder containing Ni, (B) a ferrite-based magnetic powder containing Mn, and (C) a thermosetting resin, wherein the component (A) contains an Fe-Ni-Cr alloy magnetic powder, the component (B) contains or does not contain a ferrite-based magnetic powder containing Zn, and the mass ratio ((Mn + Zn) / Fe) of the total amount of Mn and Zn to the amount of Fe in the total magnetic powder contained in the components (A) and (B) is 0.055 or more and 0.16 or less. <2> The resin composition according to <1>, wherein the component (B) has an average particle size (D 50 ) smaller than that of the component (A). <3> The resin composition according to <1> or <2>, wherein the component (C) contains (C-1) an epoxy resin. <4> The resin composition according to any one of <1> to <3>, wherein the component (C) contains (C-2) a curing agent. <5> Furthermore, the resin composition according to any one of <1> to <4>, further containing (E) a thermoplastic resin. <6> Furthermore, the resin composition according to any one of <1> to <5>, further containing (F) a curing accelerator. <7> Furthermore, the resin composition according to any one of <1> to <6>, comprising a (G) dispersant. <8> The resin composition according to any one of <1> to <7>, wherein the content of Ni contained in the component (A) is 33% by mass or more and 65% by mass or less with respect to 100% by mass of the component (A). <9> The resin composition according to any one of <1> to <8>, wherein the content of Mn contained in the component (B) is 5% by mass or more and 35% by mass or less with respect to 100% by mass of the component (B). <10> The resin composition according to any one of <1> to <9>, wherein the amount of the component (A) is 30% by volume or more with respect to 100% by volume of the non-volatile components in the resin composition. <11> The resin composition according to any one of <1> to <10>, wherein the amount of the component (A) is 40% by mass or more with respect to 100% by mass of the non-volatile components in the resin composition. <12> The resin composition according to any one of <1> to <11>, wherein the amount of the component (B) is 10% by volume or more with respect to 100% by volume of the non-volatile components in the resin composition. <13> The resin composition according to any one of <1> to <12>, wherein the amount of the component (B) is 10% by mass or more with respect to 100% by mass of the non-volatile components in the resin composition. <14> The resin composition according to any one of <1> to <13>, wherein the total amount of the component (A) and the component (B) is 60% by volume or more with respect to 100% by volume of the non-volatile components in the resin composition. <15> The resin composition according to any one of <1> to <14>, wherein the total amount of the component (A) and the component (B) is 70% by mass or more with respect to 100% by mass of the non-volatile components in the resin composition. <16> The resin composition according to any one of <1> to <15>, which is for hole filling. <17> A cured product of the resin composition according to any one of <1> to <16>. <18> <1> to <16> any one of the resin compositions described in the resin composition-containing magnetic paste. <19> Comprising a support and a resin composition layer provided on the support, The resin composition layer contains the resin composition according to any one of <1> to <16>, a resin sheet. <20> A circuit board comprising a substrate having holes and a cured product of the resin composition according to any one of <1> to <16> filled in the holes. <21> A circuit board comprising a cured product layer containing a cured product of the resin composition according to any one of <1> to <16>. <22> An inductor substrate comprising the circuit board according to <21>.

Advantages of the Invention

[0008] According to the present invention, a resin composition capable of obtaining a cured product with improved relative permeability and magnetic loss; a cured product of the resin composition; a magnetic paste and a resin sheet containing the resin composition; and a circuit board and an inductor substrate containing a cured product of the resin composition; can be provided.

Brief Description of the Drawings

[0009]

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Mode for Carrying Out the Invention

[0010] Hereinafter, the present invention will be described in detail with reference to embodiments and examples. However, the present invention is not limited to the following embodiments and examples, and can be arbitrarily modified and implemented without departing from the scope of the claims of the present invention and its equivalent scope.

[0011] In the following description, the "non-volatile component" of the resin composition represents the components excluding the solvent among the components contained in the resin composition. Further, the "resin component" of the resin composition represents the components excluding inorganic particles such as magnetic powder among the non-volatile components contained in the resin composition.

[0012] In the following description, "permeability" represents "specific permeability" unless otherwise specified.

[0013] [Resin Composition] The resin composition of the present invention is a resin composition containing (A) an iron alloy-based magnetic powder containing Ni, (B) a ferrite-based magnetic powder containing Mn, and (C) a thermosetting resin, wherein the component (A) contains an Fe-Ni-Cr alloy magnetic powder, and the component (B) contains or does not contain a ferrite-based magnetic powder containing Zn, and the mass ratio ((Mn + Zn) / Fe) of the total amount of Mn and Zn to the amount of Fe in the total magnetic powder contained in the components (A) and (B) is 0.055 or more and 0.16 or less. According to such a resin composition, the specific permeability and magnetic loss of the cured product of the resin composition can be improved. Specifically, the specific permeability of the cured product can be increased, and the magnetic loss can be decreased.

[0014] According to the resin composition of the present invention, a cured product with improved specific permeability and magnetic loss can be obtained. The cured product of the resin composition of the present invention has a higher permeability and lower magnetic loss compared to the cured product of a conventional resin composition that does not satisfy the relationship that the mass ratio ((Mn + Zn) / Fe) of the total amount of Mn and Zn to the amount of Fe in the total magnetic powder contained in the components (A) and (B) is 0.055 or more and 0.16 or less.

[0015] The cured product of a resin composition containing a magnetic powder of an iron alloy system containing Ni (and thus, an Fe-Ni-Cr alloy magnetic powder) generally can have a high relative permeability, while having a tendency of large magnetic loss. Therefore, conventionally, it has been difficult to obtain a cured product having a high relative permeability and a small magnetic loss. In view of such conventional circumstances, the effect of the resin composition capable of improving both the relative permeability and the magnetic loss is industrially beneficial.

[0016] In the resin composition of the present invention, when the component (B) does not contain a "ferrite-based magnetic powder containing Zn", in the above-mentioned "mass ratio of the total amount of Mn and Zn to the amount of Fe in the entire magnetic powder contained in the component (A) and the component (B) ((Mn + Zn) / Fe)", the content of Zn can be 0. Therefore, regarding the aspect in which the component (B) does not contain a "ferrite-based magnetic powder containing Zn", the resin composition of the present invention is characterized in that the mass ratio (Mn / Fe) of the amount of Mn to the amount of Fe in the entire magnetic powder contained in the component (A) and the component (B) is 0.055 or more and 0.16 or less.

[0017] Hereinafter, each component contained in the resin composition will be described in detail.

[0018] <(A) Magnetic powder of an iron alloy system containing Ni> The resin composition contains, as the component (A), a magnetic powder of an iron alloy system containing (A) Ni. Further, the component (A) contains an Fe-Ni-Cr alloy magnetic powder. The magnetic powder of an iron alloy system containing (A) Ni may be used alone or in combination of two or more.

[0019] Component (A) may further contain a ferromagnetic powder of an iron alloy system containing Fe and an arbitrary element other than Ni and Cr in addition to the Fe-Ni-Cr alloy ferromagnetic powder. Therefore, the ferromagnetic powder of an iron alloy system containing (A) Ni may contain, in addition to the Fe-Ni-Cr alloy ferromagnetic powder, ferromagnetic powders of an iron alloy system such as Fe-Ni-Si alloy ferromagnetic powder, Fe-Ni-B alloy ferromagnetic powder, Fe-Ni-Mo alloy ferromagnetic powder, Fe-Ni-Si-Cr alloy ferromagnetic powder, Fe-Ni-Mo-Cu alloy ferromagnetic powder, etc. In the present specification, the term "E1-E2 alloy ferromagnetic powder" represents an alloy ferromagnetic powder containing element E1 and element E2, and the term "E1-E2-E3 alloy ferromagnetic powder" represents an alloy ferromagnetic powder containing element E1, E2, and E3. The same applies to alloy ferromagnetic powders containing four or more elements.

[0020] Examples of the arbitrary element that component (A) may contain include, for example, elements derived from impurities that may inevitably be mixed in according to the production method of component (A). Specific examples of elements derived from impurities that may inevitably be mixed in include P, S, Mn, Mo, Cu, and Co. However, from the viewpoint of significantly exhibiting the effects of the present invention, the amount of elements derived from impurities contained in component (A) is preferably less than 1% by mass with respect to 100% by mass of component (A).

[0021] In a preferred embodiment, component (A) contains one or more ferromagnetic powders selected from the group consisting of Fe-Ni-Cr alloy ferromagnetic powder and Fe-Ni-Si-Cr alloy ferromagnetic powder.

[0022] The amount of each element contained in component (A) can be measured by an inductively coupled plasma optical emission spectrometer (for example, "ICP-OES 720ES" manufactured by Agilent Technologies).

[0023] The amount of Fe contained in component (A) is preferably 33% by mass or more, more preferably 38% by mass or more, still more preferably 43% by mass or more, or 48% by mass or more, and preferably 65% by mass or less, more preferably 60% by mass or less, still more preferably 55% by mass or less, or 53% by mass or less, based on 100% by mass of component (A). When the amount of Fe is within the above range, the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0024] The amount of Ni contained in component (A) is preferably 33% by mass or more, more preferably 38% by mass or more, still more preferably 42% by mass or more, or 44% by mass or more, and preferably 65% by mass or less, more preferably 60% by mass or less, still more preferably 52% by mass or less, or 48% by mass or less, based on 100% by mass of component (A). When the amount of Ni is within the above range, the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0025] The total amount of Fe and Ni contained in component (A) is preferably 85% by mass or more, more preferably 87% by mass or more, still more preferably 92% by mass or more, and preferably 99% by mass or less, more preferably 98.5% by mass or less, still more preferably 98% by mass or less, based on 100% by mass of component (A). When the total amount of Fe and Ni is within the above range, the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0026] The mass ratio (Fe / Ni) of the amount of Fe to the amount of Ni contained in component (A) is preferably 0.5 or more, more preferably 0.7 or more, still more preferably 1 or more, and preferably 1.21 or less, more preferably 1.19 or less, still more preferably 1.17 or less. When the ratio (Fe / Ni) of the amount of Fe to the amount of Ni is within the above range, the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0027] The amount of Cr contained in component (A) is preferably 1% by mass or more, more preferably 1.5% by mass or more, still more preferably 1.8% by mass or more, with respect to 100% by mass of component (A), and is preferably 5% by mass or less, more preferably 4% by mass or less, still more preferably 3.5% by mass or less, even more preferably 3% by mass or less, 2.5% by mass or less, or 2% by mass or less. When the amount of Cr is within the above range, the relative magnetic permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0028] The mass ratio (Ni / Cr) of the amount of Ni to the amount of Cr contained in component (A) is preferably 10 or more, more preferably 13 or more, still more preferably 15 or more, even more preferably 18 or more, still even more preferably 20 or more, 21 or more, 22 or more, or 23 or more, and is preferably 50 or less, more preferably 40 or less, still more preferably 30 or less. When the ratio (Ni / Cr) of the amount of Ni to the amount of Cr is within the above range, the relative magnetic permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0029] When component (A) contains an Fe-Ni-Si-Cr alloy magnetic powder, the amount of Si contained in the Fe-Ni-Si-Cr alloy magnetic powder is preferably less than 1% by mass, more preferably 0.9% by mass or less, still more preferably 0.8% by mass or less, or 0.7% by mass or less, with respect to 100% by mass of component (A). The lower limit of the amount of Si is not particularly limited, and can be, for example, 0.1% by mass or more.

[0030] (The average particle size (D 50 ) of component (A) is preferably 1 μm or more, more preferably 2 μm or more, still more preferably 3 μm or more. When the average particle size (D 50 ) of component (A) is equal to or greater than the above lower limit value, it is preferable from the viewpoint of safety in handling component (A). Further, the average particle size (D 50When (A) is equal to or greater than the lower limit value, the magnetic powder containing the (A) component and the (B) component and the resin component containing the (C) thermosetting resin can be mixed with high uniformity. Therefore, the uneven distribution of the (A) component and the (B) component due to aggregation can be effectively suppressed. Thus, the relative permeability and magnetic loss of the cured product can be effectively improved. The average particle size (D 50 ) of the (A) component preferably has an upper limit of 10 μm or less, more preferably 8 μm or less, and still more preferably 7 μm or less. When the average particle size (D 50 ) of the (A) component is equal to or less than the upper limit value, the particles of the (A) component can be small. Therefore, since the generation of large eddy current loss due to large particles can be suppressed, the magnetic loss can be effectively suppressed. This effect is particularly effective when the amount of the (A) component is large.

[0031] Unless otherwise specified, the average particle size (D 50 ) of the (A) component represents the median diameter on a volume basis. This average particle size (D 50 ) can be measured by the laser diffraction / scattering method based on the Mie scattering theory. Specifically, a particle size distribution is created on a volume basis using a laser diffraction / scattering type particle size distribution measuring device, and the median diameter is taken as the average particle size (D 50 ) for measurement. As the measurement sample, a powder dispersed in water by ultrasonic waves can preferably be used. As the laser diffraction / scattering type particle size distribution measuring device, "LA-500" manufactured by Horiba, Ltd., "SALD-2200" manufactured by Shimadzu Corporation, etc. can be used.

[0032] The specific surface area of the (A) component is preferably 0.05 m 2 / g or more, more preferably 0.1 m 2 / g or more, still more preferably 0.5 m 2 / g or more, and preferably 20 m 2 / g or less, more preferably 10 m 2 / g or less, still more preferably 5 m 2is below / g. When the specific surface area of the component (A) is within the above range, the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved. The specific surface area of the magnetic powder can be measured by the BET method. Specifically, the specific surface area can be measured by adsorbing nitrogen gas on the sample surface using a specific surface area measuring device ("Macsorb HM Model 1210" manufactured by Mountech Co., Ltd.) in accordance with the BET method and using the BET multi-point method.

[0033] The particles of the component (A) are preferably spherical or ellipsoidal particles. The value obtained by dividing the length of the major axis of the particles of the component (A) by the length of the minor axis (aspect ratio) is preferably 2 or less, more preferably 1.6 or less, and even more preferably 1.4 or less. When the aspect ratio of the component (A) is within the above range, the magnetic loss can be suppressed and the viscosity of the resin composition can be lowered.

[0034] The true density of the component (A) is, for example, 4 g / cm 3 ~10 g / cm 3 and can be in the range of.

[0035] There is no limitation on the production method of the component (A). The component (A) can be produced, for example, using an atomization method. In this atomization method, usually, the component (A) is obtained by a method including spraying high-pressure water or gas to cause rapid solidification while dropping a molten bath containing iron and nickel. Among the above atomization methods, the water atomization method of spraying water on the dropping molten bath is preferred. As such an atomization method, for example, the method described in JP-A-2018-178254 can be adopted.

[0036] The content (volume %) of component (A) contained in the resin composition is preferably 30 volume % or more, more preferably 40 volume % or more, still more preferably 45 volume % or more, 47 volume % or more, or 48 volume % or more, and preferably 70 volume % or less, more preferably 65 volume % or less, still more preferably 60 volume % or less, or 58 volume % or less, based on the total 100 volume % of components (A) to (C). When the content of component (A) is within the above range, the relative magnetic permeability and magnetic loss of the cured product of the resin composition can be effectively improved. Also, when the content of component (A) is below the upper limit value of the above range, the viscosity of the resin composition can be effectively reduced to easily make it into a paste form.

[0037] The content (volume %) of each component in the resin composition on a volume basis is determined by calculation from the mass of the components contained in the resin composition. Specifically, the volume of each component is obtained by dividing the mass by the specific gravity, and the content (volume %) on a volume basis can be obtained by calculation from the volumes of the components thus obtained.

[0038] The content (mass %) of component (A) contained in the resin composition is preferably 40 mass % or more, more preferably 50 mass % or more, still more preferably 55 mass % or more, and preferably 90 mass % or less, more preferably 85 mass % or less, still more preferably 80 mass % or less, based on the total 100 mass % of components (A) to (C). When the content of component (A) is within the above range, the relative magnetic permeability and magnetic loss of the cured product of the resin composition can be effectively improved. Also, when the content of component (A) is below the upper limit value of the above range, the viscosity of the resin composition can be effectively reduced to easily make it into a paste form.

[0039] When the resin composition contains components other than the components (A) to (C), the content (volume %) of the component (A) contained in the resin composition is preferably 30% by volume or more, more preferably 35% by volume or more, still more preferably 40% by volume or more or 42% by volume or more, and preferably 70% by volume or less, more preferably 60% by volume or less, still more preferably 55% by volume or less, based on 100% by volume of the non-volatile components contained in the resin composition. When the content of the component (A) is within the above range, the relative magnetic permeability and magnetic loss of the cured product of the resin composition can be effectively improved. Further, when the content of the component (A) is equal to or less than the upper limit value of the above range, the viscosity of the resin composition can be effectively reduced and it can be easily made into a paste form.

[0040] When the resin composition contains components other than the components (A) to (C), the content (mass %) of the component (A) contained in the resin composition is preferably 40% by mass or more, more preferably 50% by mass or more, still more preferably 60% by mass or more, and preferably 85% by mass or less, more preferably 80% by mass or less, still more preferably 75% by mass or less, based on 100% by mass of the non-volatile components contained in the resin composition. When the content of the component (A) is within the above range, the relative magnetic permeability and magnetic loss of the cured product of the resin composition can be effectively improved. Further, when the content of the component (A) is equal to or less than the upper limit value of the above range, the viscosity of the resin composition can be effectively reduced and it can be easily made into a paste form.

[0041] <(B) Ferrite-based magnetic powder containing Mn> The resin composition contains, as the component (B), a ferrite-based magnetic powder containing (B) Mn. Further, the component (B) may or may not contain a ferrite-based magnetic powder containing Zn. The ferrite-based magnetic powder containing (B) Mn may be used alone or in combination of two or more.

[0042] The ferrite-based magnetic powder usually consists of a composite oxide mainly composed of iron oxide and is chemically stable. Therefore, according to the ferrite-based magnetic powder, advantages such as high corrosion resistance, low risk of ignition, and difficulty in demagnetization can be obtained.

[0043] (B) components include, for example, Mn-based ferrite powder, Mn-Zn-based ferrite powder, Fe-Mn-based ferrite powder, Mn-Mg-based ferrite powder, Mn-Mg-Sr-based ferrite powder, and the like. In this specification, the term "E1-based ferrite powder" represents a ferrite powder containing element E1, the term "E1-E2-based ferrite powder" represents a ferrite powder containing elements E1 and E2, and the term "E1-E2-E3-based ferrite powder" represents a ferrite powder containing elements E1, E2, and E3. The same applies to ferrite powders containing four or more elements. In the ferrite powder, when the elements such as element E1 and element E2 contain Fe, the Fe means divalent iron, not trivalent iron derived from iron oxide (Fe2O3).

[0044] (B) component is preferably at least one ferrite powder selected from the group consisting of Mn-based ferrite powder and Mn-Zn-based ferrite powder. When the range of such a preferred (B) component is defined as the (B-1) component, regarding the mass ratio ((Mn + Zn) / Fe) of the total amount of Mn and Zn to the amount of Fe in the total magnetic powder contained in the (A) component and the (B) component, it is more preferable that the amount of Mn and the amount of Zn are derived from the (B-1) component. That is, it is more preferable that the mass ratio ((Mn + Zn) / Fe) of the total amount of Mn and Zn to the amount of Fe in the total magnetic powder contained in the (A) component and the (B-1) component is 0.055 or more and 0.16 or less.

[0045] (B) the amount of Fe contained in the component is preferably 33% by mass or more, more preferably 38% by mass or more, still more preferably 42% by mass or more or 43% by mass or more, and preferably 70% by mass or less, more preferably 65% by mass or less, still more preferably 60% by mass or less, 58% by mass or less or 57% by mass or less, based on 100% by mass of the (B) component. When the amount of Fe is within the above range, the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0046] The amount of Mn contained in component (B) is preferably 5% by mass or more, more preferably 7% by mass or more, still more preferably 10% by mass or more or 12% by mass or more, and preferably 35% by mass or less, more preferably 30% by mass or less, still more preferably 28% by mass or less or 26% by mass or less, based on 100% by mass of component (B). When the amount of Mn is within the above range, the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0047] When component (B) is an Mn-Zn ferrite powder, the amount of Zn contained in component (B) is preferably 1% by mass or more, more preferably 3% by mass or more, still more preferably 5% by mass or more or 6% by mass or more, and preferably 15% by mass or less, more preferably 10% by mass or less, still more preferably 8% by mass or less or 7% by mass or less, based on 100% by mass of component (B). When the amount of Zn is within the above range, the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0048] The total amount of Mn and Zn contained in component (B) is preferably 5% by mass or more, more preferably 7% by mass or more, still more preferably 10% by mass or more or 12% by mass or more, and preferably 35% by mass or less, more preferably 30% by mass or less, still more preferably 28% by mass or less or 26% by mass or less, based on 100% by mass of component (B). When the amounts of Mn and Zn contained in component (B) are within the above range, the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0049] Component (B) preferably has an average particle size (D 50 ) smaller than that of the magnetic powder of the iron alloy system containing (A) Ni. When component (B) has an average particle size smaller than that of the magnetic powder of the iron alloy system containing (A) Ni, component (B) can enter the gaps between the particles of component (A), enabling high filling of the magnetic powder, and thus improving magnetic properties such as relative permeability.

[0050] The average particle size (D 50 ) of component (A) to the average particle size (D 50The ratio of ((the average particle diameter (D of component (B)) / (the average particle diameter (D of component (A)))) is preferably within a specific range. Specifically, the ratio of the average particle diameter (D of component (B)) / (the average particle diameter (D of component (A))) is preferably 0.001 or more, more preferably 0.01 or more, still more preferably 0.05 or more, and preferably 0.9 or less, more preferably 0.6 or less, still more preferably 0.3 or less. When the ratio of the average particle diameter (D is within the above range, the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved. 50 )) / (the average particle diameter (D of component (A)) 50 )) is preferably within a specific range. Specifically, the ratio of the average particle diameter (D 50 )) of ((the average particle diameter (D of component (B)) / (the average particle diameter (D of component (A)))) 50 ) / (the average particle diameter (D of component (A))) 50 )) is preferably 0.001 or more, more preferably 0.01 or more, still more preferably 0.05 or more, and preferably 0.9 or less, more preferably 0.6 or less, still more preferably 0.3 or less. When the ratio of the average particle diameter (D 50 )) is within the above range, the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0051] The specific range of the average particle diameter (D of component (B)) is preferably 0.05 μm or more, more preferably 0.1 μm or more, still more preferably 0.2 μm or more, and preferably 3 μm or less, more preferably 2 μm or less, still more preferably 1.5 μm or less. When the average particle diameter (D of component (B)) is equal to or greater than the above lower limit value, the viscosity of the resin composition can be reduced. When it is equal to or less than the upper limit value, the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved. 50 ) is preferably 0.05 μm or more, more preferably 0.1 μm or more, still more preferably 0.2 μm or more, and preferably 3 μm or less, more preferably 2 μm or less, still more preferably 1.5 μm or less. When the average particle diameter (D of component (B)) is equal to or greater than the above lower limit value, the viscosity of the resin composition can be reduced. When it is equal to or less than the upper limit value, the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved. 50 ) is within the above range, the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0052] The average particle diameter (D of component (B)) can be measured by the same method as the average particle diameter (D of component (A)). 50 ) can be measured by the same method as the average particle diameter (D of component (A)). 50 )

[0053] Component (B) preferably has a larger specific surface area than the iron alloy-based magnetic powder containing (A) Ni. The specific range of the specific surface area of component (B) is preferably 0.1 m 2 / g or more, more preferably 1.0 m 2 / g or more, still more preferably 2 m 2 / g or more, and preferably 40 m 2 / g or less, more preferably 30 m 2 / g or less, still more preferably 20 m 2 / g or less.

[0054] The particles of component (B) are preferably spherical or ellipsoidal particles. The value obtained by dividing the length of the major axis of the particles of component (B) by the length of the minor axis (aspect ratio) is preferably 2 or less, more preferably 1.5 or less, and even more preferably 1.2 or less. When the aspect ratio of component (B) is within the above range, magnetic loss can be suppressed and the viscosity of the resin composition can be lowered.

[0055] The true density of component (B) is, for example, 4 g / cm 3 ~10 g / cm 3 and can be in the range.

[0056] The content (volume %) of component (B) contained in the resin composition is preferably 15 volume % or more, more preferably 20 volume % or more, and even more preferably 25 volume % or more, and preferably 60 volume % or less, more preferably 50 volume % or less, and even more preferably 40 volume % or less or 39 volume % or less, based on 100 volume % of the total of components (A) to (C). When the content of component (B) is within the above range, the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0057] The content (mass %) of component (B) contained in the resin composition is preferably 10 mass % or more, more preferably 15 mass % or more, and even more preferably 20 mass % or more or 21 mass % or more, and preferably 50 mass % or less, more preferably 40 mass % or less, and even more preferably 35 mass % or less or 34 mass % or less, based on 100 mass % of the total of components (A) to (C). When the content of component (B) is within the above range, the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0058] The volume ratio of component (B) to component (A) ((content of component (B) (volume %) / content of component (A) (volume %))) is preferably within a specific range. Specifically, the volume ratio ((content of component (B) (volume %) / content of component (A) (volume %))) is preferably 0.01 or more, more preferably 0.1 or more, still more preferably 0.3 or more or 0.4 or more, and preferably 2 or less, more preferably 1.5 or less, still more preferably 1 or less or 0.9 or less. When the volume ratio ((content of component (B) (volume %) / content of component (A) (volume %))) is within the above range, the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0059] The mass ratio of component (B) to component (A) ((content of component (B) (mass %) / content of component (A) (mass %))) is preferably within a specific range. Specifically, the mass ratio ((content of component (B) (mass %) / content of component (A) (mass %))) is preferably 0.01 or more, more preferably 0.1 or more, still more preferably 0.2 or more or 0.25 or more, and preferably 1 or less, more preferably 0.7 or less, still more preferably 0.5 or less. When the mass ratio ((content of component (B) (mass %) / content of component (A) (mass %))) is within the above range, the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0060] When the resin composition contains components other than components (A) to (C), the content of component (B) (volume %) contained in the resin composition is preferably 10 volume % or more, more preferably 15 volume % or more, still more preferably 20 volume % or more, 22 volume % or more or 24 volume % or more, and preferably 50 volume % or less, more preferably 45 volume % or less, still more preferably 40 volume % or less, 38 volume % or less or 37 volume % or less, based on 100 volume % of the non-volatile components contained in the resin composition. When the content of component (B) is within the above range, the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved. Further, when the content of component (B) is equal to or less than the upper limit value of the above range, the viscosity of the resin composition can be effectively reduced to easily make it into a paste form.

[0061] When the resin composition contains components other than the components (A) to (C), the content (% by mass) of the component (B) contained in the resin composition is preferably 10% by mass or more, more preferably 15% by mass or more, still more preferably 20% by mass or more, and preferably 45% by mass or less, more preferably 40% by mass or less, still more preferably 35% by mass or less or 34% by mass or less, based on 100% by mass of the non-volatile components contained in the resin composition. When the content of the component (B) is within the above range, the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved. Further, when the content of the component (B) is not more than the upper limit value of the above range, the viscosity of the resin composition can be effectively reduced to easily make it into a paste form.

[0062] When the resin composition contains components other than the components (A) to (C), the total amount (% by volume) of the components (A) and (B) contained in the resin composition is preferably 60% by volume or more, more preferably 70% by volume or more, still more preferably 75% by volume or more or 77% by volume or more, and preferably 90% by volume or less, more preferably 85% by volume or less, still more preferably 80% by volume or less or 79% by volume or less, based on 100% by volume of the non-volatile components contained in the resin composition. When the total amount of the components (A) and (B) is within the above range, the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0063] When the resin composition contains components other than the components (A) to (C), the total amount (% by mass) of the components (A) and (B) contained in the resin composition is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, 92% by mass or more or 94% by mass or more, and preferably 98% by mass or less, more preferably 97% by mass or less, still more preferably 96% by mass or less, based on 100% by mass of the non-volatile components contained in the resin composition. When the total amount of the components (A) and (B) is within the above range, the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0064] <(C) Thermosetting resin> The resin composition contains a (C) thermosetting resin as the (C) component. The (C) thermosetting resin can bind magnetic powders including an iron alloy-based magnetic powder containing (A) Ni and a ferrite-based magnetic powder containing (B) Mn. Further, the (C) thermosetting resin can react by heat to form a bond and can be cured. Therefore, a cured product can be obtained by curing a resin composition containing in combination an iron alloy-based magnetic powder containing (A) Ni, a ferrite-based magnetic powder containing (B) Mn, and the (C) thermosetting resin. Since this cured product is excellent in relative permeability and magnetic loss, an excellent magnetic layer can be formed.

[0065] Examples of the (C) thermosetting resin include an epoxy resin, a phenolic resin, an active ester resin, an amine resin, an acid anhydride resin, a benzoxazine resin, a cyanate ester resin, a carbodiimide resin, and the like. The (C) thermosetting resin may be used alone or in combination of two or more.

[0066] The (C) thermosetting resin preferably contains a (C-1) epoxy resin. The (C-1) epoxy resin represents a resin having one or more epoxy groups in the molecule. When the (C) thermosetting resin contains the (C-1) epoxy resin, the dispersibility of magnetic powders such as the (A) component and the (B) component can be enhanced, and the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0067] (C-1) Examples of the epoxy resin include bisxylenol type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, phenol novolak type epoxy resin, glycidylamine type epoxy resin, glycidyl ester type epoxy resin, cresol novolak type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin, epoxy resin having a butadiene structure, alicyclic epoxy resin, alicyclic epoxy resin having an ester skeleton, heterocyclic epoxy resin, spiro ring-containing epoxy resin, cyclohexane type epoxy resin, cyclohexanedimethanol type epoxy resin, trimethylol type epoxy resin, tetraphenylethane type epoxy resin, naphthylene ether type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, naphthol novolak type epoxy resin, and other epoxy resins containing a condensed ring skeleton such as isocyanurate type epoxy resin, epoxy resin containing an alkyleneoxy skeleton and a butadiene skeleton, fluorene structure-containing epoxy resin, etc. The (C-1) epoxy resin may be used alone or in combination of two or more.

[0068] (C-1) The epoxy resin preferably includes an epoxy resin having two or more epoxy groups in one molecule. The ratio of the epoxy resin having two or more epoxy groups in one molecule is preferably 50% by mass or more, more preferably 60% by mass or more, and still more preferably 70% by mass or more based on 100% by mass of the total amount of the (C-1) epoxy resin.

[0069] (C-1) Epoxy resins include epoxy resins that are liquid at 20°C (hereinafter sometimes referred to as "liquid epoxy resins") and epoxy resins that are solid at 20°C (hereinafter sometimes referred to as "solid epoxy resins"). The (C-1) epoxy resin may be only a liquid epoxy resin, only a solid epoxy resin, or a combination of a liquid epoxy resin and a solid epoxy resin. Among them, the (C-1) epoxy resin preferably contains a liquid epoxy resin, and more preferably contains only a liquid epoxy resin.

[0070] As the liquid epoxy resin, a liquid epoxy resin having two or more epoxy groups in one molecule is preferred. Examples of the liquid epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, phenol novolac type epoxy resin, alicyclic epoxy resin having an ester skeleton, cyclohexane type epoxy resin, cyclohexanedimethanol type epoxy resin, epoxy resin having a butadiene structure, epoxy resin containing an alkyleneoxy skeleton and a butadiene skeleton, epoxy resin containing a fluorene structure, and dicyclopentadiene type epoxy resin. Among them, bisphenol A type epoxy resin and bisphenol F type epoxy resin are more preferred.

[0071] Specific examples of the liquid epoxy resin include "YX7400" manufactured by Mitsubishi Chemical Corporation; "HP4032", "HP4032D", "HP4032SS" (naphthalene-type epoxy resin) manufactured by DIC Corporation; "828US", "828EL", "825", "Epicoat 828EL" (bisphenol A-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "807", "1750" (bisphenol F-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "152" (phenol novolac-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "630", "630LSD", "604" (glycidylamine-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "ED-523T" (glycerol-type epoxy resin) manufactured by ADEKA Corporation; "EP-3950L", "EP-3980S" (glycidylamine-type epoxy resin) manufactured by ADEKA Corporation; "EP-4088S" (dicyclopentadiene-type epoxy resin) manufactured by ADEKA Corporation; "ZX-1059" (a mixture of bisphenol A-type epoxy resin and bisphenol F-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "EX-721" (glycidyl ester-type epoxy resin) manufactured by Nagase ChemteX Corporation; "EX-991L" (epoxy resin containing an alkyleneoxy skeleton) manufactured by Nagase ChemteX Corporation; "Celloxide 2021P", "Celloxide 2081" (alicyclic epoxy resin having an ester skeleton) manufactured by Daicel Corporation; "PB-3600", "JP-100", "JP-200" (epoxy resin having a butadiene structure) manufactured by Nippon Soda Co., Ltd.; "ZX-1658", "ZX-1658GS" (liquid 1,4-glycidylcyclohexane-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "EG-280" (epoxy resin containing a fluorene structure) manufactured by Osaka Gas Chemical Co., Ltd.; and the like. The liquid epoxy resin may be used alone or in combination of two or more.

[0072] As the solid epoxy resin, a solid epoxy resin having three or more epoxy groups in one molecule is preferable, and an aromatic solid epoxy resin having three or more epoxy groups in one molecule is more preferable. Examples of the solid epoxy resin include a bixylenol type epoxy resin, a naphthalene type epoxy resin, a naphthalene type tetrafunctional epoxy resin, a cresol novolak type epoxy resin, a dicyclopentadiene type epoxy resin, a trisphenol type epoxy resin, a naphthol type epoxy resin, a biphenyl type epoxy resin, a naphthylene ether type epoxy resin, an anthracene type epoxy resin, a bisphenol A type epoxy resin, a bisphenol AF type epoxy resin, and a tetraphenylethane type epoxy resin, with a dicyclopentadiene type epoxy resin being more preferable.

[0073] Specific examples of the solid epoxy resin include "HP4032H" (naphthalene-type epoxy resin) manufactured by DIC Corporation; "HP-4700" and "HP-4710" (naphthalene-type tetrafunctional epoxy resin) manufactured by DIC Corporation; "N-690" (cresol novolak-type epoxy resin) manufactured by DIC Corporation; "N-695" (cresol novolak-type epoxy resin) manufactured by DIC Corporation; "HP-7200", "HP-7200HH", and "HP-7200H" (dicyclopentadiene-type epoxy resin) manufactured by DIC Corporation; "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", and "HP6000" (naphthylene ether-type epoxy resin) manufactured by DIC Corporation; "EPPN-502H" (trisphenol-type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC7000L" (naphthol novolak-type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC3000H", "NC3000", "NC3000L", and "NC3100" (biphenyl-type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "ESN475V" (naphthol-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "ESN485" (naphthol novolak-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YX4000H", "YX4000", and "YL6121" (biphenyl-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX4000HK" (bixylenol-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX8800" (anthracene-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX7700" (novolak-type epoxy resin containing a xylene structure) manufactured by Mitsubishi Chemical Corporation; "PG-100" and "CG-500" manufactured by Osaka Gas Chemical Co., Ltd.; "YL7760" (bisphenol AF-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YL7800" (fluorene-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "1010" (solid bisphenol A-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "1031S" (tetraphenylethane-type epoxy resin) manufactured by Mitsubishi Chemical Corporation, etc. The solid epoxy resin may be used alone or in combination of two or more types.

[0074] When a liquid epoxy resin and a solid epoxy resin are used in combination as the epoxy resin, the mass ratio of the liquid epoxy resin to the solid epoxy resin (liquid epoxy resin / solid epoxy resin) is preferably 0.5 or more, more preferably 1 or more, still more preferably 5 or more, and even more preferably 10 or more.

[0075] (C-1) The weight average molecular weight (Mw) of the epoxy resin is preferably 100 to 5000, more preferably 250 to 3000, and still more preferably 400 to 1500. The weight average molecular weight of the resin can be measured as a value in terms of polystyrene by the gel permeation chromatography (GPC) method.

[0076] The content (mass%) of the component (C-1) contained in the resin composition is preferably 0.1 mass% or more, more preferably 0.5 mass% or more, and still more preferably 1 mass% or more, and preferably 10 mass% or less, more preferably 5 mass% or less, and still more preferably 3 mass% or less, based on 100 mass% of the total of (A) to (C). When the content of the (C-1) epoxy resin is within the above range, the specific permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0077] When the resin composition contains components other than the components (A) to (C), the content (mass%) of the component (C-1) contained in the resin composition is preferably 0.1 mass% or more, more preferably 0.5 mass% or more, and still more preferably 1 mass% or more, and preferably 10 mass% or less, more preferably 5 mass% or less, and still more preferably 3 mass% or less, based on 100 mass% of the non-volatile components contained in the resin composition. When the content of the (C-1) epoxy resin is within the above range, the specific permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0078] When the resin composition contains components other than the components (A) to (C), the content (% by mass) of the component (C-1) contained in the resin composition is preferably 30% by mass or more, more preferably 35% by mass or more, still more preferably 40% by mass or more, preferably 60% by mass or less, more preferably 50% by mass or less, still more preferably 45% by mass or less, 43% by mass or less, or 42% by mass or less, based on 100% by mass of the resin components contained in the resin composition. When the content of the (C-1) epoxy resin is within the above range, the relative magnetic permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0079] (C) When the thermosetting resin contains a (C-1) epoxy resin, the (C) thermosetting resin may contain a resin capable of reacting and bonding with the (C-1) epoxy resin. A resin capable of reacting and bonding with the (C-1) epoxy resin may be hereinafter referred to as the “(C-2) curing agent”. Examples of the (C-2) curing agent include phenolic resins, active ester resins, amine resins, carbodiimide resins, acid anhydride resins, benzoxazine resins, cyanate ester resins, thiol resins, and the like. The (C-2) curing agent may be used alone or in combination of two or more. Among them, phenolic resins are preferred.

[0080] As the phenolic resin, a resin having one or more, preferably two or more hydroxyl groups bonded to an aromatic ring such as a benzene ring or a naphthalene ring in one molecule can be used. From the viewpoints of heat resistance and water resistance, a phenolic resin having a novolak structure is preferred. From the viewpoint of adhesion, a nitrogen-containing phenolic resin is preferred, and a phenolic resin containing a triazine skeleton is more preferred. Among them, from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion, a phenolic novolak resin containing a triazine skeleton is preferred.

[0081] Specific examples of the phenolic resin include, for example, "MEH-7700", "MEH-7810", "MEH-7851", "MEH-8000H" manufactured by Meiwa Kasei Co., Ltd.; "NHN", "CBN", "GPH" manufactured by Nippon Kayaku Co., Ltd.; "SN-170", "SN-180", "SN-190", "SN-475", "SN-485", "SN-495", "SN-495V", "SN-375", "SN-395" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "TD-2090", "TD-2090-60M", "LA-7052", "LA-7054", "LA-1356", "LA-3018", "LA-3018-50P", "EXB-9500", "HPC-9500", "KA-1160", "KA-1163", "KA-1165" manufactured by DIC Corporation; "GDP-6115L", "GDP-6115H", "ELPC75", etc. manufactured by Gunei Chemical Industry Co., Ltd.

[0082] As the active ester resin, a compound having one or more, preferably two or more active ester groups in one molecule can be used. Among them, as the active ester resin, compounds having two or more highly reactive ester groups in one molecule, such as phenolic esters, thiophenolic esters, N-hydroxyamine esters, esters of heterocyclic hydroxy compounds, etc., are preferred. The active ester resin is preferably obtained by a condensation reaction of a carboxylic acid compound and / or a thiocarboxylic acid compound with a hydroxy compound and / or a thiol compound. In particular, from the viewpoint of improving heat resistance, an active ester resin obtained from a carboxylic acid compound and a hydroxy compound is preferred, and an active ester resin obtained from a carboxylic acid compound and a phenol compound and / or a naphthol compound is more preferred. Examples of the carboxylic acid compound include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, etc. Examples of the phenol compound or naphthol compound include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalein, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadiene type diphenol compound, phenol novolak, etc. Here, the "dicyclopentadiene type diphenol compound" refers to a diphenol compound obtained by condensing two molecules of phenol with one molecule of dicyclopentadiene.

[0083] Preferred specific examples of the active ester resin include an active ester resin containing a dicyclopentadiene type diphenol structure, an active ester resin containing a naphthalene structure, an active ester resin containing an acetylated product of phenol novolak, and an active ester resin containing a benzoylated product of phenol novolak. Among them, an active ester resin containing a naphthalene structure and an active ester resin containing a dicyclopentadiene type diphenol structure are more preferred. The "dicyclopentadiene type diphenol structure" represents a divalent structural unit composed of phenylene-dicyclopentylene-phenylene.

[0084] Commercially available products of the active ester resin include, as an active ester resin containing a dicyclopentadiene type diphenol structure, "EXB9451", "EXB9460", "EXB9460S", "HPC-8000-65T", "EXB-8000L-65TM" (manufactured by DIC Corporation); as an active ester resin containing a naphthalene structure, "EXB-9416-70BK", "EXB-8100L-65T" (manufactured by DIC Corporation); as an active ester resin containing an acetylated product of phenol novolak, "DC808" (manufactured by Mitsubishi Chemical Corporation); as an active ester resin containing a benzoylated product of phenol novolak, "YLH1026" (manufactured by Mitsubishi Chemical Corporation); as an active ester resin which is an acetylated product of phenol novolak, "DC808" (manufactured by Mitsubishi Chemical Corporation); as an active ester resin which is a benzoylated product of phenol novolak, "YLH1026" (manufactured by Mitsubishi Chemical Corporation), "YLH1030" (manufactured by Mitsubishi Chemical Corporation), "YLH1048" (manufactured by Mitsubishi Chemical Corporation); and the like.

[0085] As the amine resin, a resin having one or more, preferably two or more amino groups in one molecule can be used. Examples of the amine resin include aliphatic amines, polyether amines, alicyclic amines, aromatic amines, and the like. Among them, aromatic amines are preferred. The amine resin is preferably a primary amine or a secondary amine, and more preferably a primary amine. Specific examples of the amine resin include 4,4'-methylenebis(2,6-dimethylaniline), diphenyldiaminosulfone, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, m-phenylenediamine, m-xylylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, 2,2-bis(3-amino-4-hydroxyphenyl)propane, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethanediamine, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)phenyl)sulfone, bis(4-(3-aminophenoxy)phenyl)sulfone, and the like. A commercially available product of the amine resin may be used, for example, "KAYABOND C-200S", "KAYABOND C-100", "KAYAHARD A-A", "KAYAHARD A-B", "KAYAHARD A-S" manufactured by Nippon Kayaku Co., Ltd., "Epicure W" manufactured by Mitsubishi Chemical Corporation, and the like.

[0086] As the carbodiimide resin, a resin having one or more, preferably two or more carbodiimide structures in one molecule can be used. Specific examples of the carbodiimide resin include aliphatic biscarbodiimides such as tetramethylene-bis(t-butylcarbodiimide) and cyclohexane bis(methylene-t-butylcarbodiimide); biscarbodiimides such as aromatic biscarbodiimides like phenylene-bis(xilylcarbodiimide); aliphatic polycarbodiimides such as polyhexamethylene carbodiimide, polytrimethylhexamethylene carbodiimide, polycyclohexylene carbodiimide, poly(methylenebiscyclohexylene carbodiimide), and poly(isophorone carbodiimide); aromatic polycarbodiimides such as poly(phenylene carbodiimide), poly(naphthylene carbodiimide), poly(tolylene carbodiimide), poly(methyldiisopropylphenylene carbodiimide), poly(triethylphenylene carbodiimide), poly(diethylphenylene carbodiimide), poly(triisopropylphenylene carbodiimide), poly(diisopropylphenylene carbodiimide), poly(xylene carbodiimide), poly(tetramethylxylene carbodiimide), poly(methylenediphenylene carbodiimide), and poly[methylenebis(methylphenylene) carbodiimide]. Commercially available products of the carbodiimide resin include, for example, "Carbodilite V-02B", "Carbodilite V-03", "Carbodilite V-04K", "Carbodilite V-07", and "Carbodilite V-09" manufactured by Nisshinbo Chemicals Co., Ltd.; "Stabaxol P", "Stabaxol P400", "Highcadyl 510", etc. manufactured by LANXESS Co., Ltd.

[0087] As the acid anhydride-based resin, a resin having one or more acid anhydride groups in one molecule can be used, and a resin having two or more acid anhydride groups in one molecule is preferable. Specific examples of the acid anhydride-based resin include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'-diphenylsulfone tetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-c]furan-1,3-dione, ethylene glycol bis(anhydrotrimellitate), and polymer-type acid anhydrides such as a styrene-maleic acid resin copolymerized from styrene and maleic acid. Commercially available products of the acid anhydride-based resin include, for example, "HNA-100", "MH-700", "MTA-15", "DDSA", "OSA" manufactured by Shin Nippon Rika Co., Ltd.; "YH-306", "YH-307" manufactured by Mitsubishi Chemical Corporation; "HN-2200", "HN-5500" manufactured by Resonaak Co., Ltd.; "EF-30", "EF-40", "EF-60", "EF-80" manufactured by Cray Valley Co., Ltd., and the like.

[0088] Specific examples of the benzoxazine-based resin include "JBZ-OD100", "JBZ-OP100D", "ODA-BOZ" manufactured by JFE Chemical Corporation; "P-d", "F-a" manufactured by Shikoku Kasei Kogyo Co., Ltd.; "HFB2006M" manufactured by Showa Highpolymer Co., Ltd., and the like.

[0089] Examples of cyanate ester resins include bifunctional cyanate resins such as bisphenol A dicyanate, polyphenol cyanate, oligo(3-methylene-1,5-phenylene cyanate), 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4'-ethylidenediphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanatephenylmethane), bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanatephenyl-1-(methylethylidene))benzene, bis(4-cyanatephenyl)thioether, and bis(4-cyanatephenyl)ether; polyfunctional cyanate resins derived from phenol novolac and cresol novolac; prepolymers in which some of these cyanate resins are triazine-ized; and the like. Specific examples of cyanate ester resins include "PT30" and "PT60" (phenol novolac type polyfunctional cyanate ester resins), "ULL-950S" (polyfunctional cyanate ester resin), "BA230", "BA230S75" (prepolymer in which some or all of bisphenol A dicyanate is triazine-ized to form a trimer), etc. manufactured by arxada.

[0090] Examples of thiol resins include trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), tris(3-mercaptopropyl) isocyanurate, and the like.

[0091] (C-2) The active group equivalent of the curing agent is preferably 50 g / eq. to 3000 g / eq., more preferably 100 g / eq. to 1000 g / eq., still more preferably 100 g / eq. to 500 g / eq., and even more preferably 100 g / eq. to 300 g / eq. The active group equivalent represents the mass of the (C-2) curing agent per equivalent of the active group.

[0092] When the epoxy equivalent of the epoxy resin in (C-1) is taken as 1, the active hydrogen equivalent of the curing agent in (C-2) is preferably 0.01 or more, more preferably 0.1 or more, still more preferably 0.5 or more, and preferably 10 or less, more preferably 5 or less, still more preferably 3 or less. The active group of the curing agent in (C-2) is an active hydroxyl group or the like, and varies depending on the type of the curing agent. Further, the epoxy equivalent of the epoxy resin in (C-1) is the total value of the values obtained by dividing the mass of the non-volatile component of each epoxy resin by the epoxy equivalent for all epoxy resins. Furthermore, the active hydrogen equivalent of the curing agent in (C-2) is the total value of the values obtained by dividing the mass of the non-volatile component of each curing agent by the active hydrogen equivalent for all curing agents.

[0093] The content (% by mass) of the component (C-2) contained in the resin composition is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, still more preferably 1% by mass or more, and preferably 10% by mass or less, more preferably 5% by mass or less, still more preferably 3% by mass or less with respect to 100% by mass of the total of the components (A) to (C). When the content of the curing agent (C-2) is within the above range, the specific magnetic permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0094] When the resin composition contains components other than the components (A) to (C), the content (% by mass) of the component (C-2) contained in the resin composition is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, still more preferably 1% by mass or more, and preferably 10% by mass or less, more preferably 5% by mass or less, still more preferably 3% by mass or less with respect to 100% by mass of the non-volatile components contained in the resin composition. When the content of the curing agent (C-2) is within the above range, the specific magnetic permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0095] When the resin composition contains components other than the components (A) to (C), the content (% by mass) of the component (C-2) contained in the resin composition is preferably 15% by mass or more, more preferably 20% by mass or more, still more preferably 25% by mass or more or 27% by mass or more, and preferably 40% by mass or less, more preferably 35% by mass or less, still more preferably 30% by mass or less or 29% by mass or less, based on 100% by mass of the resin components contained in the resin composition. When the content of the (C-2) curing agent is within the above range, the relative magnetic permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0096] (C) The range of the weight average molecular weight (Mw) of the thermosetting resin can usually be the same as the range of the weight average molecular weight of the above-mentioned (C-1) epoxy resin.

[0097] The content (% by mass) of the component (C) contained in the resin composition is preferably 0.1% by mass or more, more preferably 1% by mass or more, still more preferably 3% by mass or more, and preferably 10% by mass or less, more preferably 7% by mass or less, still more preferably 5% by mass or less, based on 100% by mass of the total non-volatile components in the components (A) to (C). When the content of the (C) thermosetting resin is within the above range, the relative magnetic permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0098] When the resin composition contains components other than the components (A) to (C), the content (% by mass) of the component (C) contained in the resin composition is preferably 0.1% by mass or more, more preferably 1% by mass or more, still more preferably 2% by mass or more or 2.5% by mass or more, and preferably 10% by mass or less, more preferably 7% by mass or less, still more preferably 5% by mass or less, based on 100% by mass of the non-volatile components contained in the resin composition. When the content of the (C) thermosetting resin is within the above range, the relative magnetic permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0099] When the resin composition contains components other than the components (A) to (C), the content (% by mass) of the component (C) contained in the resin composition is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 65% by mass or more or 68% by mass or more, and preferably 80% by mass or less, more preferably 75% by mass or less, still more preferably 70% by mass or less, based on 100% by mass of the resin components contained in the resin composition. When the content of the (C) thermosetting resin is within the above range, the relative magnetic permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0100] <(D) Optional magnetic powder (magnetic powder other than component (A) and component (B))> The resin composition may further contain, as an optional component, (D) a magnetic powder other than the components (A) and (B) in combination with the above-described components (A) to (C). The "(D) magnetic powder other than the components (A) and (B)" as this component (D) may be referred to as "(D) optional magnetic powder" as appropriate.

[0101] (D) As the optional magnetic powder, particles of a material having a relative magnetic permeability greater than 1 can be used. The material of the (D) optional magnetic powder is usually an inorganic material, and may be a soft magnetic material or a hard magnetic material. Also, the material of the (D) optional magnetic powder may be used alone or in combination of two or more. Therefore, the (D) optional magnetic powder may be a soft magnetic powder, a hard magnetic powder, or a combination of a soft magnetic powder and a hard magnetic powder. Also, the (D) optional magnetic powder may be used alone or in combination of two or more. Among them, the (D) optional magnetic powder preferably contains a soft magnetic powder, and more preferably contains only a soft magnetic powder.

[0102] (D) Examples of the optional magnetic powder include magnetic metal oxide powder and magnetic metal powder.

[0103] Examples of the magnetic metal oxide powder include ferrite-based magnetic powder; and iron oxide powder such as iron (III) oxide powder and magnetite powder; and the like.

[0104] Examples of the ferrite magnetic powder include Mg-Zn ferrite powder, Mg-Sr ferrite powder, Cu-Zn ferrite powder, Ni-Zn ferrite powder, Ni-Zn-Cu ferrite powder, Ba-Zn ferrite powder, Ba-Mg ferrite powder, Ba-Ni ferrite powder, Ba-Co ferrite powder, Ba-Ni-Co ferrite powder, Y ferrite powder, and the like.

[0105] Examples of the magnetic metal powder include pure iron powder; crystalline or amorphous alloy magnetic powders such as Fe-Si alloy powder, Fe-Si-Al alloy powder, Fe-Cr alloy powder, Fe-Cr-Si alloy powder, Fe-Cr-Al alloy powder, Fe-Co alloy powder, and Co-based amorphous alloy powder; amorphous alloys such as Co-based amorphous; and the like.

[0106] When the resin composition contains (D) any magnetic powder, the content (volume %) of the component (D) contained in the resin composition is preferably 20 volume % or less, more preferably 10 volume % or less, still more preferably 5 volume % or less, and even more preferably 3 volume % or less with respect to 100 volume % of the non-volatile components of the resin composition. The lower limit of the content (volume %) of the component (D) may be 0 volume %, or may be more than 0 volume %. Among them, the lower limit of the content (volume %) of the component (D) is preferably 0 volume %. When the content (volume %) of the (D) any magnetic powder is within the above range, the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0107] When the resin composition contains (D) any magnetic powder, the amount (mass %) of the (D) any magnetic powder contained in the resin composition is preferably 30 mass % or less, more preferably 15 mass % or less, still more preferably 7.5 mass % or less, and even more preferably 5 mass % or less with respect to 100 mass % of the non-volatile components of the resin composition. The lower limit of the content (mass %) of the (D) component may be 0 mass %, or may be more than 0 mass %. Among them, the lower limit of the content (mass %) of the (D) component is preferably 0 mass %. When the content (mass %) of the (D) any magnetic powder is within the above range, the relative permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0108] <(E) Thermoplastic resin> The resin composition may further contain (E) a thermoplastic resin as an optional component in combination with the above-described components (A) to (D). The (E) thermoplastic resin as the (E) component does not include those corresponding to the above-described components (A) to (D). According to the (E) thermoplastic resin, the mechanical properties of the cured product of the resin composition can be effectively improved.

[0109] Examples of the (E) thermoplastic resin include phenoxy resin, polyimide resin, polyvinyl acetal resin, polyolefin resin, polybutadiene resin, polyamideimide resin, polyetherimide resin, polysulfone resin, polyethersulfone resin, polyphenylene ether resin, polycarbonate resin, polyetheretherketone resin, polyester resin, and the like. The (E) thermoplastic resin may be used alone or in combination of two or more.

[0110] Examples of the phenoxy resin include phenoxy resins having one or more skeletons selected from the group consisting of a bisphenol A skeleton, a bisphenol F skeleton, a bisphenol S skeleton, a bisphenol acetophenone skeleton, a novolak skeleton, a biphenyl skeleton, a fluorene skeleton, a dicyclopentadiene skeleton, a norbornene skeleton, a naphthalene skeleton, an anthracene skeleton, an adamantane skeleton, a terpene skeleton, and a trimethylcyclohexane skeleton. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. Specific examples of the phenoxy resin include "1256" and "4250" manufactured by Mitsubishi Chemical Corporation (both are bisphenol A skeleton-containing phenoxy resins); "YX8100" manufactured by Mitsubishi Chemical Corporation (bisphenol S skeleton-containing phenoxy resin); "YX6954" manufactured by Mitsubishi Chemical Corporation (bisphenol acetophenone skeleton-containing phenoxy resin); "FX280" and "FX293" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YL7500BH30", "YX6954BH30", "YX7553", "YX7553BH30", "YL7769BH30", "YL6794", "YL7213", "YL7290", "YL7482", and "YL7891BH30" manufactured by Mitsubishi Chemical Corporation; etc.

[0111] Specific examples of the polyimide resin include "SLK-6100" manufactured by Shin-Etsu Chemical Co., Ltd., "Lica Coat SN20" and "Lica Coat PN20" manufactured by Shin Nippon Rika Co., Ltd., etc. Specific examples of the polyimide resin also include linear polyimides obtained by reacting bifunctional hydroxyl group-terminated polybutadiene, diisocyanate compounds, and tetracarboxylic acid anhydrides (polyimides described in JP-A-2006-37083), modified polyimides such as polyimides containing a polysiloxane skeleton (polyimides described in JP-A-2002-12667 and JP-A-2000-319386), etc.

[0112] Examples of the polyvinyl acetal resin include, for example, polyvinyl formal resin and polyvinyl butyral resin, and polyvinyl butyral resin is preferred. Specific examples of the polyvinyl acetal resin include Esrec BH series, BX series (for example, BX-5Z), KS series (for example, KS-1), BL series, BM series, etc. manufactured by Sekisui Chemical Co., Ltd.

[0113] Examples of the polyolefin resin include ethylene-based copolymer resins such as low-density polyethylene, ultra-low density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, etc.; polyolefin polymers such as polypropylene, ethylene-propylene block copolymer, etc.

[0114] Examples of the polybutadiene resin include, for example, resins containing a hydrogenated polybutadiene skeleton, hydroxyl group-containing polybutadiene resin, phenolic hydroxyl group-containing polybutadiene resin, carboxy group-containing polybutadiene resin, acid anhydride group-containing polybutadiene resin, epoxy group-containing polybutadiene resin, isocyanate group-containing polybutadiene resin, urethane group-containing polybutadiene resin, polyphenylene ether-polybutadiene resin, etc.

[0115] Specific examples of the polyamideimide resin include "Vironmax HR11NN" and "Vironmax HR16NN" manufactured by Toyobo Co., Ltd. Specific examples of the polyamideimide resin also include modified polyamideimides such as "KS9100" and "KS9300" (polyamideimide containing a polysiloxane skeleton) manufactured by Hitachi Chemical Co., Ltd.

[0116] Specific examples of the polyethersulfone resin include "PES5003P" manufactured by Sumitomo Chemical Co., Ltd.

[0117] Specific examples of the polysulfone resin include polysulfone "P1700", "P3500", etc. manufactured by Solvay Advanced Polymers, LLC.

[0118] Specific examples of the polyphenylene ether resin include "NORYL SA90" manufactured by SABIC, etc. Specific examples of the polyetherimide resin include "ULTEM" manufactured by GE, etc.

[0119] Examples of the polycarbonate resin include a hydroxy group-containing carbonate resin, a phenolic hydroxyl group-containing carbonate resin, a carboxy group-containing carbonate resin, an acid anhydride group-containing carbonate resin, an isocyanate group-containing carbonate resin, a urethane group-containing carbonate resin, etc. Specific examples of the polycarbonate resin include "FPC0220" manufactured by Mitsubishi Gas Chemical Company, "T6002", "T6001" (polycarbonate diol) manufactured by Asahi Kasei Corporation, "C-1090", "C-2090", "C-3090" (polycarbonate diol) manufactured by Kuraray Co., Ltd., etc. Specific examples of the polyetheretherketone resin include "Sumipro EK" manufactured by Sumitomo Chemical Company, etc.

[0120] Examples of the polyester resin include polyethylene terephthalate resin, polyethylene naphthalate resin, polybutylene terephthalate resin, polybutylene naphthalate resin, polytrimethylene terephthalate resin, polytrimethylene naphthalate resin, polycyclohexanedimethylene terephthalate resin, etc.

[0121] (E) The weight average molecular weight (Mw) of the thermoplastic resin is preferably greater than 5,000, more preferably 8,000 or more, still more preferably 10,000 or more, and even more preferably 20,000 or more. The upper limit has no particular limitation and can be, for example, 1 million or less, 500,000 or less, 100,000 or less, etc.

[0122] When the resin composition contains (E) a thermoplastic resin, the content (% by mass) of the (E) component contained in the resin composition is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, still more preferably 0.1% by mass or more, and preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 1% by mass or less, based on 100% by mass of the non-volatile components of the resin composition. When the amount of the (E) thermoplastic resin is within the above range, the relative magnetic permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0123] When the resin composition contains (E) a thermoplastic resin, the content (% by mass) of the (E) component contained in the resin composition is preferably 1% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, and preferably 25% by mass or less, more preferably 20% by mass or less, still more preferably 15% by mass or less, based on 100% by mass of the resin components of the resin composition. When the amount of the (E) thermoplastic resin is within the above range, the relative magnetic permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0124] <(F) Curing accelerator> The resin composition may further contain, as an optional component, (F) a curing accelerator in combination with the above-described components (A) to (E). The (F) curing accelerator as the (F) component does not include those corresponding to the above-described components (A) to (E). Since the (F) curing accelerator functions as a catalyst for the reaction of the (B) thermosetting resin, it can accelerate the curing of the resin composition.

[0125] Examples of the (F) curing accelerator include imidazole-based curing accelerators, phosphorus-based curing accelerators, amine-based curing accelerators, guanidine-based curing accelerators, metal-based curing accelerators, urea-based curing accelerators, and the like. The (F) curing accelerator may be used alone or in combination of two or more. Among them, as the (F) curing accelerator, imidazole-based curing accelerators and phosphorus-based curing accelerators are preferred, and imidazole-based curing accelerators are more preferred.

[0126] Examples of imidazole-based curing accelerators include imidazole compounds such as 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, 2-phenylimidazoline, and adducts of imidazole compounds and epoxy resins. 2-Ethyl-4-methylimidazole and 1-benzyl-2-phenylimidazole are preferred. As the imidazole-based curing accelerator, commercially available products may be used. For example, "P200-H50" manufactured by Mitsubishi Chemical Corporation; "Curezol 2MZ", "2E4MZ", "Cl1Z", "Cl1Z-CN", "Cl1Z-CNS", "Cl1Z-A", "2MZ-OK", "2MA-OK", "2MA-OK-PW", "2MZA-PW", "2PHZ", "2PHZ-PW", "1B2PZ", "1B2PZ-10M", etc. manufactured by Shikoku Kasei Kogyo Co., Ltd.

[0127] Examples of phosphorus-based curing accelerators include phosphonium salts and phosphines. Examples of phosphonium salts include aliphatic phosphonium salts such as tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium acetate, tetrabutylphosphonium decanoate, tetrabutylphosphonium laurate, n-butylphosphonium tetraphenylborate, bis(tetrabutylphosphonium) pyromellitate, tetrabutylphosphonium hydrogen hexahydrophthalate, tetrabutylphosphonium 2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-methylphenolate, di-tert-butylmethylphosphonium tetraphenylborate; aromatic phosphonium salts such as methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, propyltriphenylphosphonium bromide, butyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, tetraphenylphosphonium bromide, p-tolyltriphenylphosphonium tetra-p-tolylborate, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetra-p-tolylborate, triphenylethylphosphonium tetraphenylborate, tris(3-methylphenyl)ethylphosphonium tetraphenylborate, tris(2-methoxyphenyl)ethylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate, etc.

[0128] Examples of phosphines include aliphatic phosphines such as tributylphosphine, tri-tert-butylphosphine, trioctylphosphine, di-tert-butyl(2-butenyl)phosphine, di-tert-butyl(3-methyl-2-butenyl)phosphine, tricyclohexylphosphine; aromatic phosphines such as dibutylphenylphosphine, di-tert-butylphenylphosphine, methyldiphenylphosphine, ethyldiphenylphosphine, butyldiphenylphosphine, diphenylcyclohexylphosphine, triphenylphosphine, tri-o-tolylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine, tris(4-ethylphenyl)phosphine, tris(4-propylphenyl)phosphine, tris(4-isopropylphenyl)phosphine, tris(4-butylphenyl)phosphine, tris(4-tert-butylphenyl)phosphine, tris(2,4-dimethylphenyl)phosphine, tris(2,5-dimethylphenyl)phosphine, tris(2,6-dimethylphenyl)phosphine, tris(3,5-dimethylphenyl)phosphine, tris(2,4,6-trimethylphenyl)phosphine, tris(2,6-dimethyl-4-ethoxyphenyl)phosphine, tris(2-methoxyphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(4-ethoxyphenyl)phosphine, tris(4-tert-butoxyphenyl)phosphine, diphenyl-2-pyridylphosphine, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,2-bis(diphenylphosphino)acetylene, 2,2'-bis(diphenylphosphino)diphenylether; aromatic phosphine-borane complexes such as triphenylphosphine·triphenylborane; aromatic phosphine-quinone addition reactants such as triphenylphosphine·p-benzoquinone addition reactant, etc.

[0129] As the phosphorus-based curing accelerator, commercially available products may be used. For example, "TBP-DA" manufactured by Kitakyo Chemical Industry Co., Ltd. etc. may be mentioned.

[0130] Examples of amine-based curing accelerators include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, 1,8-diazabicyclo(5,4,0)-undecene, 1,8-diazabicyclo[5,4,0]undecene-7, 4-dimethylaminopyridine, 2,4,6-tris(dimethylaminomethyl)phenol, etc. Among them, 4-dimethylaminopyridine is preferred. As the amine-based curing accelerator, commercially available products may be used. For example, "PN-50", "PN-23", "MY-25", etc. manufactured by Ajinomoto Fine-Techno Co., Ltd. can be mentioned.

[0131] Examples of guanidine-based curing accelerators include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylbiguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1-allylbiguanide, 1-phenylbiguanide, 1-(o-tolyl)biguanide, etc. Among them, dicyandiamide and 1,5,7-triazabicyclo[4.4.0]dec-5-ene are preferred.

[0132] Examples of the metal-based hardening accelerators include organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, tin, etc. Specific examples of the organometallic complexes include organocobalt complexes such as cobalt(II) acetylacetonate and cobalt(III) acetylacetonate, organocopper complexes such as copper(II) acetylacetonate, organozinc complexes such as zinc(II) acetylacetonate, organoiron complexes such as iron(III) acetylacetonate, organonickel complexes such as nickel(II) acetylacetonate, and organomanganese complexes such as manganese(II) acetylacetonate. Examples of the organometallic salts include zinc octylate, tin octylate, zinc naphthenate, cobalt naphthenate, tin stearate, zinc stearate, etc.

[0133] Examples of the urea-based hardening accelerators include 1,1-dimethylurea; aliphatic dimethylureas such as 1,1,3-trimethylurea, 3-ethyl-1,1-dimethylurea, 3-cyclohexyl-1,1-dimethylurea, and 3-cyclooctyl-1,1-dimethylurea; aromatic dimethylureas such as 3-phenyl-1,1-dimethylurea, 3-(4-chlorophenyl)-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, 3-(3-chloro-4-methylphenyl)-1,1-dimethylurea, 3-(2-methylphenyl)-1,1-dimethylurea, 3-(4-methylphenyl)-1,1-dimethylurea, 3-(3,4-dimethylphenyl)-1,1-dimethylurea, 3-(4-isopropylphenyl)-1,1-dimethylurea, 3-(4-methoxyphenyl)-1,1-dimethylurea, 3-(4-nitrophenyl)-1,1-dimethylurea, 3-[4-(4-methoxyphenoxy)phenyl]-1,1-dimethylurea, 3-[4-(4-chlorophenoxy)phenyl]-1,1-dimethylurea, 3-[3-(trifluoromethyl)phenyl]-1,1-dimethylurea, N,N-(1,4-phenylene)bis(N’,N’-dimethylurea), and N,N-(4-methyl-1,3-phenylene)bis(N’,N’-dimethylurea) [toluene bisdimethylurea].

[0134] When the resin composition contains (F) a curing accelerator, the content (% by mass) of the (F) component contained in the resin composition is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, still more preferably 0.01% by mass or more, and preferably 2% by mass or less, more preferably 1% by mass or less, still more preferably 0.1% by mass or less, based on 100% by mass of the non-volatile components of the resin composition. When the content of the (F) curing accelerator is within the above range, the specific magnetic permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0135] When the resin composition contains (F) a curing accelerator, the content (% by mass) of the (F) component contained in the resin composition is preferably 0.01% by mass or more, more preferably 0.10% by mass or more, still more preferably 0.20% by mass or more, and preferably 3% by mass or less, more preferably 1% by mass or less, still more preferably 0.5% by mass or less, based on 100% by mass of the resin components of the resin composition. When the content of the (F) curing accelerator is within the above range, the specific magnetic permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0136] <(G) Dispersant> The resin composition may further contain (G) a dispersant as an optional component in combination with the above-described components (A) to (F). The (G) dispersant as the (G) component does not include those corresponding to the above-described components (A) to (F). According to the (G) dispersant, the dispersibility of the magnetic powder containing (A) an iron alloy-based magnetic powder containing Ni and (B) a ferrite-based magnetic powder containing Mn (furthermore, (D) an arbitrary magnetic powder) can be enhanced.

[0137] There is no limitation on the type of the (G) dispersant. For example, as the (G) dispersant, those containing a functional group having an adsorption ability to the magnetic powder and dispersing the magnetic powder by repulsion (e.g., electrostatic repulsion, steric repulsion, etc.) between the (G) dispersants when adsorbed on the magnetic powder can be used. Examples of such (G) dispersants include acidic dispersants and basic dispersants.

[0138] Acidic dispersants usually contain acidic functional groups such as carboxyl groups, sulfo groups (-SO3H), sulfuric acid groups (-OSO3H), phosphono groups (-PO(OH)2), phosphonoxy groups (-OPO(OH)2), hydroxyphosphoryl groups (-PO(OH)-), sulfanyl groups (-SH), etc. Acidic functional groups usually have dissociable protons and may be neutralized by bases such as amines and hydroxide ions. Preferred acidic dispersants include, for example, acidic polymer dispersants containing polymer chains such as polyoxyalkylene chains and polyether chains. Preferred examples of acidic dispersants include "C-2093I" and "SC-1015F (a multifunctional comb-shaped functional polymer having an ionic group in the main chain and a polyoxyalkylene chain in the graft chain)" manufactured by NOF Corporation; "ED152", "ED153", "ED154", "ED118", "ED174", "ED251", "DA-375" (a polyether-type phosphate ester-based dispersant) manufactured by Kusumoto Chemicals, Ltd.; "RS-410", "RS-610", "RS-710" (pH is 1.9) (a phosphate ester-based dispersant) of the "Phosphanol" series manufactured by Toho Chemical Industry Co., Ltd.; "AKM-0531", "AFB-1521", "SC-0505K", "SC-0708A" of the "Marialim" series manufactured by NOF Corporation;

[0139] Basic dispersants usually contain basic functional groups such as primary, secondary, and tertiary amino groups; ammonium groups; imino groups; and nitrogen-containing heterocyclic groups such as pyridine, pyrimidine, pyrazine, imidazole, and triazole. Basic functional groups may be neutralized by acids such as organic acids and inorganic acids. Preferred basic dispersants include, for example, basic polymer dispersants containing polymer chains such as polyester chains. Preferred examples of basic dispersants include "PB-881" (a polyamine-based dispersant containing a polyester chain) manufactured by Ajinomoto Fine-Techno Co., Inc.

[0140] (G) The dispersant may be used alone or in combination of two or more.

[0141] When the resin composition contains the (G) dispersant, the content (% by mass) of the (G) component contained in the resin composition is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, still more preferably 0.5% by mass or more, and preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 1% by mass or less, based on 100% by mass of the non-volatile components of the resin composition. When the content of the (G) dispersant is within the above range, the specific magnetic permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0142] When the resin composition contains the (G) dispersant, the content (% by mass) of the (G) component contained in the resin composition is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, and preferably 30% by mass or less, more preferably 25% by mass or less, still more preferably 20% by mass or less, based on 100% by mass of the resin component of the resin composition. When the content of the (G) dispersant is within the above range, the specific magnetic permeability and magnetic loss of the cured product of the resin composition can be effectively improved.

[0143] <(H) Optional Additive> The resin composition may further contain, as an optional component, (H) an optional additive in combination with the above-described components (A) to (G). The (H) optional additive as the (H) component does not include those corresponding to the above-described components (A) to (G).

[0144] (H) As optional additives, for example, radical polymerizable compounds such as maleimide-based radical polymerizable compounds, vinylphenyl-based radical polymerizable compounds, (meth)acrylic-based radical polymerizable compounds, allyl-based radical polymerizable compounds, polybutadiene-based radical polymerizable compounds; radical polymerization initiators such as peroxide-based radical polymerization initiators, azo-based radical polymerization initiators; inorganic fillers such as silica particles; organic fillers such as rubber particles; organometallic compounds such as organic copper compounds, organic zinc compounds; polymerization inhibitors such as hydroquinone, catechol, pyrogallol, phenothiazine; leveling agents such as silicone-based leveling agents, acrylic polymer-based leveling agents; thickeners such as benton, montmorillonite; antifoaming agents such as silicone-based antifoaming agents, acrylic-based antifoaming agents, fluorine-based antifoaming agents, vinyl resin-based antifoaming agents; ultraviolet absorbers such as benzotriazole-based ultraviolet absorbers; adhesion improvers such as urea silane; adhesion imparting agents such as triazole-based adhesion imparting agents, tetrazole-based adhesion imparting agents, triazine-based adhesion imparting agents; antioxidants such as hindered phenol-based antioxidants; flame retardants such as phosphorus-based flame retardants (for example, phosphate ester compounds, phosphazene compounds, phosphinic acid compounds, red phosphorus), nitrogen-based flame retardants (for example, melamine sulfate), halogen-based flame retardants, inorganic-based flame retardants (for example, antimony trioxide); stabilizers such as borate-based stabilizers, titanate-based stabilizers, aluminate-based stabilizers, zirconate-based stabilizers, isocyanate-based stabilizers, carboxylic acid-based stabilizers, carboxylic anhydride-based stabilizers, etc. can be mentioned. (H) The optional additives may be used alone or in combination of two or more.

[0145] <(I) Solvent> The resin composition may further contain (I) a solvent as a volatile component in combination with the non-volatile components such as the above-mentioned components (A) to (H).

[0146] (I) Usually, an organic solvent is used as the solvent. (I) Examples of the solvent include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, and γ-butyrolactone; ether solvents such as tetrahydropyran, tetrahydrofuran, 1,4-dioxane, diethyl ether, diisopropyl ether, dibutyl ether, and diphenyl ether; alcohol solvents such as methanol, ethanol, propanol, butanol, and ethylene glycol; ether ester solvents such as 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl diglycol acetate, γ-butyrolactone, and methyl methoxypropionate; ester alcohol solvents such as methyl lactate, ethyl lactate, and methyl 2-hydroxyisobutyrate; ether alcohol solvents such as 2-methoxypropanol, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, and diethylene glycol monobutyl ether (butyl carbitol); amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; sulfoxide solvents such as dimethyl sulfoxide; nitrile solvents such as acetonitrile and propionitrile; aliphatic hydrocarbon solvents such as hexane, cyclopentane, cyclohexane, and methylcyclohexane; aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and trimethylbenzene, etc. (I) The solvent may be used alone or in combination of two or more.

[0147] (I) The content of the solvent is preferably set so as to adjust the melt viscosity of the resin composition to an appropriate range. (I) The content of the solvent can be, for example, 3% by mass or less, 1% by mass or less, 0.5% by mass or less, 0.1% by mass or less, 0.01% by mass or less with respect to 100% by mass of the non-volatile components in the resin composition. When the content of the (I) solvent contained in the resin composition is small, the generation of voids due to the volatilization of the (I) solvent can be suppressed, and furthermore, the handleability and workability of the resin composition can be improved.

[0148] [Properties and Applications of Resin Composition] The above-described resin composition can be cured by heat. Therefore, a cured product of the resin composition can be obtained by thermally curing the resin composition. Usually, among the components contained in the resin composition, volatile components such as the (I) solvent can be volatilized by the heat during thermal curing, but non-volatile components such as the components (A) to (H) are not volatilized by the heat during thermal curing. Therefore, the cured product of the resin composition can contain the non-volatile components of the resin composition or reaction products thereof.

[0149] Therefore, according to the above resin composition, a cured product having a high relative permeability can be obtained. For example, when the relative permeability of a cured product obtained by thermally curing the resin composition at 190 °C for 90 minutes is measured under the conditions of a measurement frequency of 20 MHz and a room temperature of 23 °C, the relative permeability is preferably 23 or more, more preferably 23.5 or more, and even more preferably 23.7 or more. There is no particular limitation on the upper limit of the relative permeability, and it can be, for example, 35 or less, or 30 or less, etc. The relative permeability of the cured product can be measured by the method described in the examples below.

[0150] In addition, according to the above resin composition, a cured product having low magnetic loss can be obtained. Magnetic loss can be represented by the loss coefficient tanδ. Generally, the smaller the loss coefficient tanδ, the smaller the magnetic loss. For example, when the loss coefficient tanδ of the cured product obtained by thermally curing the resin composition at 190 °C for 90 minutes is measured under the conditions of a measurement frequency of 20 MHz and a room temperature of 23 °C, the loss coefficient tanδ is preferably 0.04 or less, more preferably 0.035 or less, and even more preferably 0.033 or less. There is no particular limitation on the lower limit of the loss coefficient, and it can be, for example, 0.00001 or more. The loss coefficient tanδ of the cured product can be measured by the method described in the examples below.

[0151] There is no particular limitation on the properties of the resin composition. Therefore, the resin composition may be in a solid state or may be in a paste state having fluidity. For example, the resin composition may be made into a paste-like resin composition using a solvent, or may be made into a paste-like resin composition by using a liquid thermosetting resin such as a liquid epoxy resin. When the content of the solvent in the resin composition is small, the generation of voids due to the volatilization of the solvent can be suppressed, and the handling property and workability can be made excellent.

[0152] Utilizing the above-described excellent properties, the resin composition is preferably used as a resin composition for manufacturing inductors. For example, the above-described resin composition is preferably used as a resin composition for filling holes in a substrate provided on a circuit board. Further, for example, the above-described resin composition is also preferably used to form a cured product layer on a circuit board. To facilitate application to these uses, the resin composition may be used in a paste form or may be used in the form of a resin sheet including a layer of the resin composition.

[0153] [Method for Producing Resin Composition] The resin composition can be produced, for example, by mixing the above-described components. The above-described components may be mixed partially or entirely at the same time, or may be mixed in sequence. During the process of mixing each component, the temperature may be appropriately set, and thus, heating and / or cooling may be performed temporarily or throughout the process. Further, stirring or shaking may be performed during the process of mixing each component. Furthermore, defoaming may be performed under low-pressure conditions such as under vacuum.

[0154] [Magnetic paste] The magnetic paste of the present invention contains the above-described resin composition. Since the magnetic paste is usually a fluid paste containing a resin composition, it can be preferably used for filling holes by a printing method. This magnetic paste may contain only the above-described resin composition, or may contain any components in combination with the resin composition. Preferably, the paste-like resin composition itself can be used as the magnetic paste.

[0155] The magnetic paste is preferably in a paste state at 23°C. The viscosity of this magnetic paste at 23°C is preferably 20 Pa·s or more, more preferably 25 Pa·s or more, still more preferably 30 Pa·s or more, and even more preferably 50 Pa·s or more, and is preferably 200 Pa·s or less, more preferably 180 Pa·s or less, and still more preferably 160 Pa·s or less. The viscosity can be measured, for example, using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., "RE-80U", 3°×R9.7 rotor) under the measurement conditions of a measurement sample amount of 0.22 ml and a rotation speed of 5 rpm.

[0156] [Resin sheet] The resin sheet of the present invention includes a support and a resin composition layer provided on the support. The resin composition layer contains the above-described resin composition and preferably contains only the resin composition.

[0157] From the viewpoint of thinning, the thickness of the resin composition layer is preferably 250 μm or less, more preferably 200 μm or less. The lower limit of the thickness of the resin composition layer can be, for example, 5 μm or more, 10 μm or more, etc.

[0158] Examples of the support include a film of a plastic material, a metal foil, and a release paper, with a film of a plastic material and a metal foil being preferred.

[0159] When using a film of a plastic material as the support, examples of the plastic material include polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate (hereinafter sometimes abbreviated as "PEN"), polycarbonate (hereinafter sometimes abbreviated as "PC"), acrylic polymers such as polymethyl methacrylate (PMMA), cyclic polyolefin, triacetyl cellulose (TAC), polyethersulfide (PES), polyether ketone, polyimide, etc. Among them, polyethylene terephthalate and polyethylene naphthalate are preferred, and inexpensive polyethylene terephthalate is particularly preferred.

[0160] When using a metal foil as the support, examples of the metal foil include a copper foil, an aluminum foil, etc., with a copper foil being preferred. As the copper foil, a foil made of single metal copper may be used, or a foil made of an alloy of copper and other metals (for example, tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.) may be used.

[0161] The support may be subjected to a mat treatment or a corona treatment on the surface that joins with the resin composition layer.

[0162] Also, as the support, a support with a release layer having a release layer on the surface that bonds to the resin composition layer may be used. Examples of the release agent used for the release layer of the support with a release layer include one or more release agents selected from the group consisting of alkyd-based release agents, polyolefin-based release agents, urethane-based release agents, and silicone-based release agents. As the support with a release layer, commercially available products may be used. For example, "PET501010", "SK-1", "AL-5", "AL-7" manufactured by Lintec Corporation, which are PET films having a release layer mainly composed of a silicone-based release agent or an alkyd resin-based release agent; "Lumirror T60" manufactured by Toray Industries, Inc.; "Purex" manufactured by Teijin Limited; "Unipile" manufactured by Unitika Ltd., etc.

[0163] The thickness of the support is not particularly limited, but a range of 5 μm to 75 μm is preferable, and a range of 10 μm to 60 μm is more preferable. When using a support with a release layer, it is preferable that the total thickness of the support with a release layer is within the above range.

[0164] In the resin sheet, a protective film similar to the support may be provided on the surface of the resin composition layer that is not bonded to the support (i.e., the surface opposite to the support). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. By providing the protective film, it is possible to suppress the adhesion of dust and the like and scratches on the surface of the resin composition layer.

[0165] The resin sheet can be produced, for example, by applying a resin composition onto a support using a die coater or the like to form a resin composition layer. If necessary, an organic solvent may be mixed into the resin composition and then applied onto the support. When using an organic solvent, drying may be performed after application if necessary.

[0166] Drying may be carried out by methods such as heating and hot air blowing. The drying conditions are not particularly limited, but the drying is carried out such that the content of the organic solvent in the resin composition layer is 10% by mass or less, preferably 5% by mass or less. Although it varies depending on the components contained in the resin composition, the resin composition layer can be formed by drying at 50°C to 150°C for 3 minutes to 10 minutes.

[0167] The resin sheet can be stored by winding it into a roll. When the resin sheet has a protective film, it can usually be used by peeling off the protective film.

[0168] [Circuit Board and Method for Manufacturing the Same] The circuit board includes a cured product of the resin composition described above. The specific structure of the circuit board is not limited as long as it includes the cured product of the resin composition. The circuit board according to the first example includes a substrate having holes and a cured product of the resin composition filled in the holes. Further, the circuit board according to the second example includes a cured product layer including the cured product of the resin composition. Hereinafter, methods for manufacturing the circuit boards according to these first and second examples will be described. However, the circuit board and the method for manufacturing the same are not limited to the first and second examples illustrated below.

[0169] <Circuit Board According to the First Example> The circuit board according to the first example includes a substrate in which holes are formed and a cured product of the resin composition filled in the holes. This circuit board is, for example, (1) a step of filling the holes of the substrate with the resin composition, and (2) a step of thermally curing the resin composition to obtain a cured product, and can be manufactured by a manufacturing method including the above steps. Further, the method for manufacturing the circuit board according to the first example further includes (3) a step of polishing the surface of the cured product or the resin composition (4) a step of subjecting the cured product to a roughening treatment, and (5) a step of forming a conductor layer on the cured product, It may be included. Usually, the above steps (1) to (5) may be performed in the order of step (1), step (2), step (3), step (4), and step (5), or step (2) may be performed after step (3). In the method for manufacturing a circuit board according to the first example, it is preferable to form a cured product using a paste-like resin composition. In the following description, an example using a substrate in which through-holes as holes penetrating the substrate in the thickness direction are formed will be shown and described.

[0170] <Step (1)> Step (1) usually includes the step of preparing a substrate in which through-holes are formed. The substrate may be prepared by purchasing it from the market. Also, the substrate may be prepared by manufacturing it using an appropriate material. Hereinafter, a method for manufacturing a substrate according to an example will be described.

[0171] FIG. 1 is a cross-sectional view schematically showing a core substrate 10 prepared in the method for manufacturing a circuit board according to the first example of an embodiment of the present invention. The step of preparing the substrate may include the step of preparing the core substrate 10 as in the example shown in FIG. 1. The core substrate 10 usually includes a support substrate 11. Examples of the support substrate 11 include insulating base materials such as glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates. Also, a metal layer may be provided on the support substrate 11. The metal layer may be provided on one side of the support substrate 11 or on both sides. Here, an example in which metal layers 12 and 13 are provided on both surfaces of the support substrate 11 is shown. Examples of the metal layers 12 and 13 include layers formed of a metal such as copper. The metal layers 12 and 13 may be, for example, copper foils such as carrier-attached copper foils, or metal layers formed of the material of the conductor layer described later.

[0172] FIG. 2 is a cross-sectional view schematically showing a core substrate 10 in which through holes 14 are formed in a method for manufacturing a circuit board according to a first example of an embodiment of the present invention. The step of preparing the substrate may include a step of forming through holes 14 in the core substrate 10 as in the example shown in FIG. 2. The through holes 14 can be formed by methods such as drilling, laser irradiation, and plasma irradiation. Usually, the through holes 14 can be formed by forming through holes in the core substrate 10. To give a specific example, the formation of the through holes 14 can be carried out using a commercially available drilling device. Examples of commercially available drilling devices include "ND-1S211" manufactured by Hitachi Via Mechanics, Ltd.

[0173] FIG. 3 is a cross-sectional view schematically showing a core substrate 10 in which a plating layer 20 is formed in the through holes 14 in a method for manufacturing a circuit board according to a first example of an embodiment of the present invention. The step of preparing the substrate may include a step of forming a plating layer 20 as shown in FIG. 3 after subjecting the core substrate 10 to roughening treatment as necessary. As the above-mentioned roughening treatment, either dry or wet roughening treatment may be performed. Examples of dry roughening treatment include plasma treatment. Also, as an example of wet roughening treatment, a method of performing swelling treatment with a swelling liquid, roughening treatment with an oxidizing agent, and neutralization treatment with a neutralizing liquid in this order can be mentioned. The plating layer 20 can be formed by a plating method. The procedure for forming the plating layer 20 by the plating method may be the same as that for forming the conductor layer in step (5) described later. Here, an example in which the plating layer 20 is formed in the through holes 14, on the surface of the metal layer 12, and on the surface of the metal layer 13 will be described.

[0174] FIG. 4 is a cross-sectional view schematically showing a state in which a resin composition 30a is filled in a through hole of a core substrate 10 in a method for manufacturing a circuit board according to a first example of an embodiment of the present invention. Step (1) includes filling the through hole 14 of the core substrate 10 with the resin composition 30a as shown in FIG. 4 after preparing the core substrate 10 having the through hole 14 formed as described above. The filling can be performed, for example, by a printing method. Examples of the printing method include a method of printing the resin composition 30a into the through hole 14 via a squeegee, a method of printing the resin composition 30a via a cartridge, a method of mask printing to print the resin composition 30a, a roll coating method, an inkjet method, and the like.

[0175] <Step (2)> FIG. 5 is a schematic cross-sectional view for explaining step (2) of a method for manufacturing a circuit board according to a first example of an embodiment of the present invention. Step (2) includes curing the resin composition 30a after filling the through hole 14 with the resin composition 30a to form a cured product 30 as shown in FIG. 5.

[0176] The curing of the resin composition 30a is usually performed by heat curing. The heat curing conditions of the resin composition 30a can be appropriately set within a range in which the curing of the resin composition 30a proceeds. The curing temperature is preferably 120°C or higher, more preferably 130°C or higher, still more preferably 150°C or higher, and preferably 245°C or lower, more preferably 220°C or lower, still more preferably 200°C or lower. The curing time is preferably 5 minutes or longer, more preferably 10 minutes or longer, still more preferably 15 minutes or longer, and preferably 120 minutes or shorter, more preferably 110 minutes or shorter, still more preferably 100 minutes or shorter.

[0177] The degree of curing of the cured product 30 obtained in step (2) is preferably 80% or higher, more preferably 85% or higher, still more preferably 90% or higher. The degree of curing can be measured, for example, using a differential scanning calorimeter.

[0178] The method for manufacturing a circuit board according to the first example may include a step (preheating step) of heating the resin composition 30a at a temperature lower than the curing temperature after filling the through-hole 14 with the resin composition 30a and before curing the resin composition 30a. For example, prior to curing the resin composition 30a, the resin composition 30a may be preheated at a temperature of usually 50°C or higher and lower than 120°C (preferably 60°C or higher and 110°C or lower, more preferably 70°C or higher and 100°C or lower) for usually 5 minutes or longer (preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes).

[0179] <Step (3)> FIG. 6 is a schematic cross-sectional view for explaining step (3) of the method for manufacturing a circuit board according to the first example of an embodiment of the present invention. When the through-hole 14 is filled with the resin composition 30a in step (1), the excess resin composition 30a may protrude or adhere outside the through-hole 14. Therefore, the resin composition 30a can be provided not only inside the through-hole 14 but also outside the through-hole 14. Thus, as shown in FIG. 6, step (3) includes polishing the excess cured product 30 protruding or adhering from the core substrate 10. By polishing, the excess cured product 30 is removed, so that the surface of the cured product 30 can be flattened. Further, the surface (polished surface) 31 of the cured product 30 flattened by polishing can usually form a flat plane flush with the surrounding surface 21 of the polished surface 31 (for example, the surface of the core substrate 10, the surface of the plating layer 20).

[0180] As a method for polishing the cured product 30, a method capable of removing the excess cured product 30 protruding or adhering from the core substrate 10 can be adopted. Examples of such polishing methods include buff polishing, belt polishing, and ceramic polishing. Examples of commercially available buff polishing devices include "NT-700IM" manufactured by Ishii Hyouki Co., Ltd.

[0181] The arithmetic mean roughness (Ra) of the polished surface 31 (the surface after curing) of the cured product 30 is preferably 300 nm or more, more preferably 350 nm or more, still more preferably 400 nm or more, from the viewpoint of improving the adhesion to the conductor layer. The upper limit is preferably 1000 nm or less, more preferably 900 nm or less, still more preferably 800 nm or less. The surface roughness (Ra) can be measured, for example, using a non-contact surface roughness meter.

[0182] The method for manufacturing a circuit board according to the first example may include a step of heat-treating the cured product 30 in order to further increase the degree of curing of the cured product 30 after step (3). The temperature in the heat treatment may conform to the curing temperature described above. The specific heat treatment temperature is preferably 120°C or more, more preferably 130°C or more, still more preferably 150°C or more, and preferably 245°C or less, more preferably 220°C or less, still more preferably 200°C or less. The heat treatment time is preferably 5 minutes or more, more preferably 10 minutes or more, still more preferably 15 minutes or more, and preferably 90 minutes or less, more preferably 70 minutes or less, still more preferably 60 minutes or less.

[0183] When step (3) is performed before step (2), a pre-heat treatment may be performed before step (3), heating at a temperature lower than the curing temperature of the resin composition. The temperature in the pre-heat treatment is preferably 100°C or more, more preferably 110°C or more, still more preferably 120°C or more, and preferably 245°C or less, more preferably 220°C or less, still more preferably 200°C or less. The heat treatment time is preferably 5 minutes or more, more preferably 10 minutes or more, still more preferably 15 minutes or more, and preferably 90 minutes or less, more preferably 70 minutes or less, still more preferably 60 minutes or less.

[0184] <Step (4)> The process (4) includes subjecting the cured product 30 to a roughening treatment (desmear treatment). By the roughening treatment, the surface of the cured product 30 is roughened. When the surface of the cured product 30 is polished, it usually includes subjecting the polished surface 31 to a roughening treatment (desmear treatment). The procedure and conditions of the roughening treatment are not particularly limited, and for example, the procedures and conditions used in the manufacturing method of a multilayer printed wiring board can be adopted. Taking a specific example, a swelling treatment with a swelling liquid, a roughening treatment with an oxidizing agent, and a neutralization treatment with a neutralizing liquid can be carried out in this order to subject the cured product 30 to a roughening treatment.

[0185] Examples of the swelling liquid that can be used in the roughening process include, for example, an alkaline solution, a surfactant solution, etc., and an alkaline solution is preferred. As the alkaline solution that is the swelling liquid, a sodium hydroxide solution and a potassium hydroxide solution are more preferred. Examples of commercially available swelling liquids include, for example, "Swelling Dip Security Gun P" and "Swelling Dip Security SBU" manufactured by Atotech Japan Co., Ltd.

[0186] The swelling treatment with the swelling liquid can be carried out, for example, by immersing the cured product 30 in the swelling liquid at 30°C to 90°C for 1 minute to 20 minutes. From the viewpoint of suppressing the swelling of the resin contained in the cured product 30 to an appropriate level, it is preferable to immerse the cured product 30 in the swelling liquid at 40°C to 80°C for 5 minutes to 15 minutes.

[0187] Examples of the oxidizing agent that can be used in the roughening treatment with the oxidizing agent include, for example, an alkaline permanganate solution in which potassium permanganate or sodium permanganate is dissolved in an aqueous solution of sodium hydroxide. The roughening treatment with an oxidizing agent such as an alkaline permanganate solution is preferably carried out by immersing the cured product 30 in the solution of the oxidizing agent heated to 60°C to 80°C for 10 minutes to 30 minutes. Also, the concentration of the permanganate in the alkaline permanganate solution is preferably 5% by mass to 10% by mass. Examples of commercially available oxidizing agents include, for example, alkaline permanganate solutions such as "Concentrate Compact P" and "Dosing Solution Security Gun P" manufactured by Atotech Japan Co., Ltd.

[0188] As the neutralizing solution that can be used for the neutralization treatment, an acidic aqueous solution is preferable. Examples of commercially available neutralizing solutions include "Reduction Solution Security P" manufactured by Atotech Japan Co., Ltd. The neutralization treatment with the neutralizing solution can be performed by immersing the treated surface, which has been roughened with the oxidizing agent solution, in the neutralizing solution at 30°C to 80°C for 5 minutes to 30 minutes. From the viewpoint of workability and the like, a method of immersing the cured product 30, which has been roughened with the oxidizing agent solution, in the neutralizing solution at 40°C to 70°C for 5 minutes to 20 minutes is preferable.

[0189] The arithmetic mean roughness (Ra) of the surface of the cured product 30 after the roughening treatment is preferably 300 nm or more, more preferably 350 nm or more, and even more preferably 400 nm or more from the viewpoint of improving the adhesion with the conductor layer. The upper limit is preferably 1500 nm or less, more preferably 1200 nm or less, and even more preferably 1000 nm or less. The surface roughness (Ra) can be measured using, for example, a non-contact surface roughness meter.

[0190] <Step (5)> FIG. 7 is a schematic cross-sectional view for explaining Step (5) of the method for manufacturing a circuit board according to the first example of an embodiment of the present invention. As shown in FIG. 7, Step (5) includes forming a conductor layer 40 on the polished surface 31 of the cured product 30. Here, an example is shown in which the conductor layer 40 is formed not only on the polished surface 31 of the cured product 30 but also on the surrounding surfaces 21 (for example, the surface of the core substrate 10, the surface of the plating layer 20). Further, FIG. 7 shows an example in which the conductor layer 40 is formed on both sides of the core substrate 10, but the conductor layer 40 may be formed on only one side of the core substrate 10.

[0191] FIG. 8 is a schematic cross-sectional view for explaining Step (5) of the method for manufacturing a circuit board according to the first example of an embodiment of the present invention. As shown in FIG. 8, Step (5) may include, after forming the conductor layer 40, removing a part of the conductor layer 40, the metal layer 12, the metal layer 13, and the plating layer 20 by a treatment such as etching to form a pattern conductor layer 41.

[0192] Examples of the method for forming the conductor layer 40 include, for example, a plating method, a sputtering method, a vapor deposition method, etc., and among them, the plating method is preferable. In a preferred embodiment, plating can be performed on the surface of the cured product 30 (and the plating layer 20) by an appropriate method such as a semi-additive method or a full-additive method to form a pattern conductor layer 41 having a desired wiring pattern. Examples of the material of the conductor layer 40 include single metals such as gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, indium, etc.; alloys of two or more metals selected from the group of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. Among them, from the viewpoints of versatility, cost, ease of patterning, etc., it is preferable to use chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or a nickel-chromium alloy, a copper-nickel alloy, a copper-titanium alloy, and it is more preferable to use chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or a nickel-chromium alloy, and it is even more preferable to use copper.

[0193] Here, an example of the method for forming the pattern conductor layer 41 on the polished surface 31 of the cured product 30 will be described in detail. A plating seed layer is formed on the polished surface 31 of the cured product 30 by electroless plating. Next, an electrolytic plating layer is formed on the formed plating seed layer by electrolytic plating. Then, if necessary, an unnecessary plating seed layer can be removed by a treatment such as etching to form a pattern conductor layer 41 having a desired wiring pattern. After the formation of the pattern conductor layer 41, an annealing treatment may be performed as necessary to improve the adhesion strength of the pattern conductor layer 41. The annealing treatment can be performed, for example, by heating at 150 to 200 ° C for 20 to 90 minutes.

[0194] From the perspective of thinning, the thickness of the pattern conductor layer 41 is preferably 70 μm or less, more preferably 60 μm or less, still more preferably 50 μm or less, even more preferably 40 μm or less, particularly preferably 30 μm or less, 20 μm or less, 15 μm or less, or 10 μm or less. The lower limit is preferably 1 μm or more, more preferably 3 μm or more, and still more preferably 5 μm or more.

[0195] By the above method, the circuit board 1 including the cured product 30 of the resin composition 30a can be manufactured.

[0196] <Circuit board according to the second example> The circuit board according to the second example includes a cured product layer containing a cured product of a resin composition. The cured product layer preferably contains only the cured product of the resin composition. The cured product layer is preferably formed using a resin sheet. This circuit board can be manufactured, for example, (i) A step of forming a cured product layer on an inner layer substrate, (ii) A step of drilling the cured product layer, (iii) A step of roughening the surface of the cured product layer, and (iv) A step of forming a conductor layer on the surface of the cured product layer, by a manufacturing method including these steps.

[0197] <Step (i)> Step (i) includes forming a cured product layer on an inner layer substrate. Preferably, step (i) includes laminating a resin sheet on the inner layer substrate such that the resin composition layer is joined to the inner layer substrate to form a cured product layer. For example, the resin sheet is laminated on the inner layer substrate such that the resin composition layer is joined to the inner layer substrate, and the resin composition layer is thermally cured to form a cured product layer.

[0198] FIG. 9 is a schematic cross-sectional view for explaining step (i) in a method for manufacturing a circuit board according to a second example of an embodiment of the present invention. As shown in FIG. 9, a resin sheet 310 including a support 330 and a resin composition layer 320a provided on the support 330 is prepared. Then, the resin sheet 310 and the inner layer substrate 200 are laminated so that the resin composition layer 320a is joined to the inner layer substrate 200.

[0199] As the inner layer substrate 200, an insulating substrate can be used. Examples of the inner layer substrate 200 include insulating base materials such as glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates. The inner layer substrate 200 may be an inner layer circuit board in which wirings and the like are formed within its thickness.

[0200] The inner layer substrate 200 shown in this example includes a first conductor layer 420 provided on the first main surface 200a and external terminals 240 provided on the second main surface 200b. The first conductor layer 420 may include a plurality of wirings. However, in the example shown in FIG. 9, only the wirings constituting the coil-shaped conductive structure 400 (see FIG. 12) of the inductor element are shown. The external terminals 240 can be terminals for electrically connecting to external devices and the like (not shown). The external terminals 240 can be configured as a part of the conductor layer provided on the second main surface 200b.

[0201] Examples of the conductor material that can form the first conductor layer 420 and the external terminals 240 include the same materials as those of the conductor layer described in the first example.

[0202] The first conductor layer 420 and the external terminals 240 may have a single-layer structure or a multi-layer structure in which two or more single metal layers or alloy layers made of different types of metals or alloys are laminated. Also, the thicknesses of the first conductor layer 420 and the external terminals 240 can be the same as those of the second conductor layer 440 described later.

[0203] The line and space (L / S) of the first conductor layer 420 and the external terminal 240 is not particularly limited, but from the viewpoint of reducing surface irregularities and obtaining a cured product layer with excellent smoothness, it is usually 900 / 900 μm or less, preferably 700 / 700 μm or less, more preferably 500 / 500 μm or less, still more preferably 300 / 300 μm or less, and even more preferably 200 / 200 μm or less. The lower limit of the line and space (L / S) is not particularly limited, but from the viewpoint of favorably embedding the resin composition layer into the space, it is preferably 1 / 1 μm or more.

[0204] The inner layer substrate 200 may have a plurality of through holes 220 penetrating the inner layer substrate 200 from the first main surface 200a to the second main surface 200b. A through hole inner wiring 220a is provided in the through hole 220. The through hole inner wiring 220a electrically connects the first conductor layer 420 and the external terminal 240.

[0205] The bonding between the resin composition layer 320a and the inner layer substrate 200 can be performed, for example, by thermocompression bonding the resin sheet 310 to the inner layer substrate 200 from the support 330 side. Examples of the member for thermocompression bonding the resin sheet 310 to the inner layer substrate 200 (hereinafter also referred to as "thermocompression bonding member") include a heated metal plate (such as a stainless steel (SUS) mirror plate) or a metal roll (SUS roll). Note that it is preferable to press through a sheet made of an elastic material such as heat-resistant rubber so that the resin sheet 310 sufficiently follows the irregularities on the surface of the inner layer substrate 200, rather than directly contacting and pressing the thermocompression bonding member against the resin sheet 310.

[0206] The temperature during heat press bonding is preferably in the range of 80°C to 160°C, more preferably in the range of 90°C to 140°C, and even more preferably in the range of 100°C to 120°C. The pressure during heat press bonding is preferably in the range of 0.098 MPa to 1.77 MPa, more preferably in the range of 0.29 MPa to 1.47 MPa. The time during heat press bonding is preferably in the range of 20 seconds to 400 seconds, more preferably in the range of 30 seconds to 300 seconds. The bonding between the resin sheet and the inner layer substrate is preferably carried out under reduced pressure conditions of 26.7 hPa or less.

[0207] The bonding between the resin composition layer 320a of the resin sheet 310 and the inner layer substrate 200 can be carried out by a commercially available vacuum laminator. Examples of commercially available vacuum laminators include a vacuum pressure type laminator manufactured by Meiki Seisakusho Co., Ltd., a vacuum applicator manufactured by Nichco Materials Co., Ltd., and the like.

[0208] After bonding the resin sheet 310 and the inner layer substrate 200, under normal pressure (atmospheric pressure), for example, the heat press bonding member can be pressed from the support 330 side to perform a smoothing process on the laminated resin sheet 310. The press conditions for the smoothing process can be the same as the heat press bonding conditions for the above lamination. The smoothing process can be carried out by a commercially available laminator. Note that the lamination and the smoothing process may be continuously carried out using the above commercially available vacuum laminator.

[0209] FIG. 10 is a schematic cross-sectional view for explaining step (i) in the method for manufacturing a circuit board according to a second example of an embodiment of the present invention. After laminating the resin sheet 310 on the inner layer substrate 200, the resin composition layer 320a is cured to form a cured product layer. In this example, as shown in FIG. 10, the resin composition layer 320a bonded to the inner layer substrate 200 is thermally cured to form the first cured product layer 320.

[0210] The thermosetting conditions of the resin composition layer 320a can be appropriately set within the range in which the curing of the resin composition progresses. The curing temperature is preferably 120 °C or higher, more preferably 130 °C or higher, still more preferably 150 °C or higher, and preferably 245 °C or lower, more preferably 220 °C or lower, still more preferably 200 °C or lower. The curing time is preferably 5 minutes or longer, more preferably 10 minutes or longer, still more preferably 15 minutes or longer, and preferably 120 minutes or shorter, more preferably 110 minutes or shorter, still more preferably 100 minutes or shorter.

[0211] The support 330 may be removed between the thermosetting in step (i) and step (ii), or may be peeled off after step (ii).

[0212] The arithmetic mean roughness (Ra) before the roughening treatment of the cured product layer is preferably 300 nm or more, more preferably 350 nm or more, still more preferably 400 nm or more, from the viewpoint of improving the adhesion to plating. The upper limit is preferably 1000 nm or less, more preferably 900 nm or less, still more preferably 800 nm or less. The surface roughness (Ra) can be measured, for example, using a non-contact surface roughness meter.

[0213] In step (i), instead of the resin sheet, a resin composition may be applied onto the inner layer substrate 200 using a die coater or the like and thermoset to form a cured product layer.

[0214] <Step (ii)> FIG. 11 is a schematic cross-sectional view for explaining step (ii) in the method for manufacturing a circuit board according to a second example of an embodiment of the present invention. As shown in FIG. 11, step (ii) includes drilling the first cured product layer 320 to form via holes 360. The via holes 360 form a path for electrically connecting the first conductor layer 420 and a second conductor layer 440 described later. The formation of the via holes 360 may be carried out, for example, using a drill, laser, plasma, or the like. The dimensions and shape of the holes may be appropriately determined according to the design of the printed wiring board.

[0215] <Step (iii)> In Step (iii), the surface of the cured layer in which via holes are formed is roughened. The roughening treatment in Step (iii) can be performed in the same manner as described in Step (4) of the first example.

[0216] The arithmetic mean roughness (Ra) of the cured layer after the roughening treatment is preferably 300 nm or more, more preferably 350 nm or more, and still more preferably 400 nm or more, from the viewpoint of improving the adhesion to plating. The upper limit is preferably 1500 nm or less, more preferably 1200 nm or less, and still more preferably 1000 nm or less. The surface roughness (Ra) can be measured, for example, using a non-contact surface roughness meter.

[0217] <Step (iv)> FIG. 12 is a schematic cross-sectional view for explaining Step (iv) in the method for manufacturing a circuit board according to the second example of an embodiment of the present invention. As shown in FIG. 12, in Step (iv), a second conductor layer 440 is formed on the first cured layer 320.

[0218] Examples of the conductor material that can constitute the second conductor layer 440 include the same materials as those of the conductor layer described in the first example.

[0219] The thickness of the second conductor layer 440 is preferably 70 μm or less, more preferably 60 μm or less, still more preferably 50 μm or less, even more preferably 40 μm or less, still more preferably 30 μm or less, 20 μm or less, 15 μm or less, or 10 μm or less, from the viewpoint of thinning. The lower limit is preferably 1 μm or more, more preferably 3 μm or more, and still more preferably 5 μm or more.

[0220] The second conductor layer 440 can be formed by plating. The second conductor layer 440 is preferably formed by a wet plating method such as an electroless plating process, a mask pattern forming process, an electrolytic plating process, a semi-additive method including a flash etching process, a full-additive method, etc. By forming the second conductor layer 440 using a wet plating method, the second conductor layer 440 including a desired wiring pattern can be formed. In addition, by this process, the in-via wiring 360a is formed in the via hole 360 at the same time.

[0221] The first conductor layer 420 and the second conductor layer 440 may be provided in a spiral shape, as shown in an example in FIGS. 13 to 15 described later. In one example, one end on the center side of the spiral wiring portion of the second conductor layer 440 is electrically connected to one end on the center side of the spiral wiring portion of the first conductor layer 420 by the in-via wiring 360a. The other end on the outer peripheral side of the spiral wiring portion of the second conductor layer 440 is electrically connected to the land 420a of the first conductor layer 420 by the in-via wiring 360a. Therefore, the other end on the outer peripheral side of the spiral wiring portion of the second conductor layer 440 is electrically connected to the external terminal 240 through the in-via wiring 360a, the land 420a, and the through-hole wiring 220a.

[0222] The coil-shaped conductive structure 400 is composed of a spiral wiring portion that is a part of the first conductor layer 420, a spiral wiring portion that is a part of the second conductor layer 440, and the in-via wiring 360a that electrically connects the spiral wiring portion of the first conductor layer 420 and the spiral wiring portion of the second conductor layer 440.

[0223] After step (iv), a step of forming a cured product layer on the conductor layer may be further performed. Specifically, as shown in an example in FIG. 14, a second cured product layer 340 is formed on the first cured product layer 320 on which the second conductor layer 440 and the in-via wiring 360a are formed. The second cured product layer may be formed by the same process as the process already described. By the above method, the circuit board 100 including the first cured product layer 320 and the second cured product layer 340 formed of the cured product of the resin composition can be manufactured.

[0224] [Inductor substrate] The inductor substrate includes the circuit substrate described above. Such an inductor substrate may have an inductor pattern formed by a conductor at least in part around the cured product of the resin composition when including the circuit substrate obtained by the manufacturing method of the circuit substrate according to the first example described above. In this case, the inductor substrate may include, for example, an inductor element composed of an inductor pattern formed by at least part of a metal layer 12, a metal layer 13, a plating layer 20, and a pattern conductor layer 41, and a core portion formed by a cured product 30 surrounded by this inductor pattern. Such an inductor substrate can be applied, for example, to those described in Japanese Patent Application Laid-Open No. 2016-197624.

[0225] Also, when including the circuit substrate obtained by the manufacturing method of the circuit substrate according to the second example, the inductor substrate may have a cured product layer and a conductive structure at least partially embedded in this cured product layer. And this inductor substrate may include an inductor element composed of the conductive structure and a part of the cured product layer that extends in the thickness direction of the cured product layer and is surrounded by the conductive structure.

[0226] FIG. 13 is a schematic plan view of a circuit substrate 100 included in the inductor substrate as viewed from one side in its thickness direction. FIG. 14 is a schematic view showing a cut end face of the circuit substrate 100 cut at the position indicated by the II-II chain line shown in FIG. 13. FIG. 15 is a schematic plan view for explaining the configuration of a first conductor layer 420 of the circuit substrate 100 included in the inductor substrate.

[0227] As shown as an example in FIGS. 13 and 14, the circuit substrate 100 may be a substrate having a plurality of cured product layers (a first cured product layer 320, a second cured product layer 340) and a plurality of conductor layers (a first conductor layer 420, a second conductor layer 440). Therefore, in the example shown here, the circuit substrate 100 may be a build-up wiring board having a build-up cured product layer and a build-up conductor layer. Also, the circuit substrate 100 includes an inner layer substrate 200.

[0228] As shown in FIG. 14, the first cured product layer 320 and the second cured product layer 340 constitute a magnetic part 300 that can be regarded as an integral cured product layer. Therefore, the coil-shaped conductive structure 400 is provided such that at least a part thereof is embedded in the magnetic part 300. That is, in the circuit board 100 shown in this example, the inductor element is composed of the coil-shaped conductive structure 400 and a core part that extends in the thickness direction of the magnetic part 300 and is a part of the magnetic part 300 surrounded by the coil-shaped conductive structure 400.

[0229] As shown as an example in FIG. 15, the first conductor layer 420 includes a spiral wiring part for forming the coil-shaped conductive structure 400 and a rectangular land 420a that is electrically connected to the in-wiring 220a in the through hole. In the example shown here, the spiral wiring part includes a bent part that bends at a right angle to the linear part and a detour part that detours around the land 420a. Further, the spiral wiring part of the first conductor layer 420 has a shape in which the overall contour is substantially rectangular and is wound counterclockwise as it goes from the center side to the outside.

[0230] Similarly, a second conductor layer 440 is provided on the first cured product layer 320. The second conductor layer 440 includes a spiral wiring part for forming the coil-shaped conductive structure 400. In FIG. 13 or FIG. 14, the spiral wiring part includes a bent part that bends at a right angle to the linear part. In FIG. 13 or FIG. 14, the spiral wiring part of the second conductor layer 44 has a shape in which the overall contour is substantially rectangular and is wound clockwise as it goes from the center side to the outside.

[0231] The above-described inductor substrate can be used as a wiring board for mounting electronic components such as semiconductor chips, and can also be used as a (multi-layer) printed wiring board using such a wiring board as an inner layer substrate. Further, such a wiring board can also be used as a chip inductor component that is separated into individual pieces, and can also be used as a printed wiring board on which the chip inductor component is surface-mounted.

[0232] Furthermore, semiconductor devices in various embodiments can be manufactured using such a wiring board. A semiconductor device including such a wiring board can be suitably used in electrical products (such as computers, mobile phones, digital cameras, and televisions, etc.) and vehicles (such as motorcycles, automobiles, trains, ships, and airplanes, etc.).

Example

[0233] Hereinafter, the present invention will be specifically described by way of examples. The present invention is not limited to these examples. In the following, “%” and “parts” representing amounts mean “mass %” and “mass parts” unless otherwise specified. Also, the temperature condition in the case where there is no particular temperature designation is room temperature (23°C). Furthermore, the pressure condition in the case where there is no particular pressure designation is normal pressure (1 atm).

[0234] <Example 1: Preparation of varnish-like resin composition 1> Fe-Ni-Cr alloy magnetic powder (manufactured by Mitsubishi Steel Co., Ltd., “AKT-PB-2Cr”, an alloy of Fe 52.2%, Ni 45.1%, Si 0.7%, Cr 1.9%, average particle size (D 50 ) 5 μm, true density 8.0 g / cm 3 ) was 65.5 mass parts, Mn-Zn ferrite powder (manufactured by Powdertech Co., Ltd., “MZ03S_1”, Mn-Zn ferrite powder of Fe 48.2%, Mn 16.5%, Zn 6.3%, average particle size (D 50 ) 0.4 μm, true density 5.1 g / cm 3 ) was 19.6 mass parts, epoxy resin (manufactured by Nippon Steel Chemical & Material Co., Ltd., “ZX-1059”, a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin, epoxy equivalent 169 g / eq., true density 1.2 g / cm 3 ) was 1.63 mass parts, phenolic resin (manufactured by DIC Corporation, “LA-7054”, aminotriazine-modified phenolic novolak resin, MEK solution with non-volatile content of 60%, hydroxyl equivalent 125 g / eq., true density of non-volatile component 1.2 g / cm 31.85 parts by mass of 3 1.61 parts by mass of phenoxy resin (「YX7553BH30」manufactured by Mitsubishi Chemical Corporation, a solution of methyl ethyl ketone: cyclohexanone = 1:1 with a non-volatile content of 30%, a special skeleton phenoxy resin, and a true density of the non-volatile content of 1.2 g / cm 3 0.70 parts by mass of a dispersant (「PB-881」manufactured by Ajinomoto Fine-Techno Co., Ltd., a polyester-based dispersant, with a true density of 1.2 g / cm 3 ), and 0.01 parts by mass of a curing accelerator (「2E4MZ」manufactured by Shikoku Kasei Kogyo Co., Ltd., an imidazole-based curing accelerator, with a true density of 1.2 g / cm

[0235] <Example 2: Preparation of Varnish Resin Composition 2> In Example 1, 1) The amount of Fe-Ni-Cr alloy magnetic powder (「AKT-PB-2Cr」manufactured by Mitsubishi Steel Manufacturing Co., Ltd.) was changed from 65.5 parts by mass to 56.4 parts by mass, 2) The amount of magnetic powder (「MZ03S_1」manufactured by Powdertech Co., Ltd.) was changed from 19.6 parts by mass to 25.0 parts by mass. Except for the above matters, Varnish Resin Composition 2 was prepared in the same manner as in Example 1.

[0236] <Example 3: Preparation of Varnish Resin Composition 3> In Example 1, 1) The amount of Fe-Ni-Cr alloy magnetic powder (「AKT-PB-2Cr」manufactured by Mitsubishi Steel Manufacturing Co., Ltd.) was changed from 65.5 parts by mass to 52.7 parts by mass, 2) The amount of Mn-Zn ferrite powder (「MZ03S_1」manufactured by Powdertech Co., Ltd.) was changed from 19.6 parts by mass to 27.9 parts by mass. Except for the above matters, Varnish Resin Composition 3 was prepared in the same manner as in Example 1.

[0237] <Example 4: Preparation of Varnish Resin Composition 4> In Example 2, 25.0 parts by mass of Mn-Zn ferrite powder (“MZ03S_1” manufactured by Powdertech Co., Ltd.) was changed to 25.0 parts by mass of Mn ferrite powder (“M03S_1” manufactured by Powdertech Co., Ltd., Mn ferrite powder with Fe 44.2% and Mn 25.1%, average particle size (D 50 ) 0.4 μm, true density 5.1 g / cm 3 ). A varnish resin composition 4 was prepared in the same manner as in Example 2 except for the above matters.

[0238] <Example 5: Preparation of Varnish Resin Composition 5> In Example 1, 19.6 parts by mass of Mn-Zn ferrite powder (“MZ03S_1” manufactured by Powdertech Co., Ltd.) was changed to 19.6 parts by mass of Mn ferrite powder (“M03S_3” manufactured by Powdertech Co., Ltd., Fe-Mn ferrite powder with Fe 56.0% and Mn 13.9%, average particle size (D 50 ) 0.4 μm, true density 5.1 g / cm 3 ). A varnish resin composition 5 was prepared in the same manner as in Example 1 except for the above matters.

[0239] <Example 6: Preparation of Varnish Resin Composition 6> In Example 2, 25.0 parts by mass of Mn-Zn ferrite powder (“MZ03S_1” manufactured by Powdertech Co., Ltd.) was changed to 25.0 parts by mass of Mn ferrite powder (“M03S_3” manufactured by Powdertech Co., Ltd., Mn ferrite powder with Fe 56.0% and Mn 13.9%, average particle size (D 50 ) 0.4 μm, true density 5.1 g / cm 3 ). A varnish resin composition 6 was prepared in the same manner as in Example 2 except for the above matters.

[0240] <Example 7: Preparation of Varnish Resin Composition 7> In Example 1, 65.5 parts by mass of Fe-Ni-Cr alloy magnetic powder (“AKT-PB-2Cr” manufactured by Mitsubishi Steel Co., Ltd.) was changed to another Fe-Ni-Cr alloy magnetic powder (“AKT-PB-1Cr” manufactured by Mitsubishi Steel Co., Ltd., alloy with Fe 53.3%, Ni 45.0%, Si 0.7%, Cr 1.0%, average particle size (D50 ) 5 μm, true density 8.0 g / cm 3 ) It was changed to 65.5 parts by mass. Except for the above matters, varnish resin composition 7 was prepared in the same manner as in Example 1.

[0241] <Example 8: Preparation of Varnish Resin Composition 8> In Example 1, 65.5 parts by mass of Fe-Ni-Cr alloy magnetic powder (“AKT-PB-2Cr” manufactured by Mitsubishi Steel Co., Ltd.) was replaced with another Fe-Ni-Cr alloy magnetic powder (“AKT-PB-3Cr” manufactured by Mitsubishi Steel Co., Ltd., alloy of Fe 51.0%, Ni 45.1%, Si 0.8%, Cr 3.1%, average particle size (D 50 ) 5 μm, true density 8.0 g / cm 3 ) It was changed to 65.5 parts by mass. Except for the above matters, varnish resin composition 8 was prepared in the same manner as in Example 1.

[0242] <Example 9: Preparation of Varnish Resin Composition 9> In Example 1, 65.5 parts by mass of Fe-Ni-Cr alloy magnetic powder (“AKT-PB-2Cr” manufactured by Mitsubishi Steel Co., Ltd.) was replaced with another Fe-Ni-Cr alloy magnetic powder (“AKT-PB-4Cr” manufactured by Mitsubishi Steel Co., Ltd., alloy of Fe 49.4%, Ni 45.9%, Si 0.8%, Cr 3.9%, average particle size (D 50 ) 5 μm, true density 8.0 g / cm 3 ) It was changed to 65.5 parts by mass. Except for the above matters, varnish resin composition 9 was prepared in the same manner as in Example 1.

[0243] <Comparative Example 1: Preparation of Varnish Resin Composition 10> In Example 2, 25.0 parts by mass of Mn-Zn ferrite powder (“MZ03S_1” manufactured by Powdertech Co., Ltd.) was replaced with another Mn-Zn ferrite powder (“MZ03S_2” manufactured by Powdertech Co., Ltd., Mn-Zn ferrite powder of Fe 43.1%, Mn 22.2%, Zn 4.8%, average particle size (D 50 ) 0.4 μm, true density 5.1 g / cm 3 ) It was changed to 25.0 parts by mass. Except for the above matters, varnish resin composition 10 was prepared in the same manner as in Example 2.

[0244] <Comparative Example 2: Preparation of Varnish Resin Composition 11> In Example 1, 19.6 parts by mass of Mn-Zn ferrite powder ("MZ03S_1" manufactured by Powdertech Co., Ltd.) was replaced with 19.6 parts by mass of Mn ferrite powder ("M03S_2" manufactured by Powdertech Co., Ltd., Mn ferrite powder with Fe 62.3% and Mn 8.1%, average particle size (D 50 ) 0.4 μm, true density 5.1 g / cm 3 ) Except for the above matters, varnish resin composition 11 was prepared in the same manner as in Example 1.

[0245] <Comparative Example 3: Preparation of Varnish Resin Composition 12> In Example 1, 1) The amount of Fe-Ni alloy magnetic powder ("AKT-PB-2Cr" manufactured by Mitsubishi Steel Co., Ltd.) was changed from 65.5 parts by mass to 41.8 parts by mass, 2) The amount of Mn-Zn ferrite powder ("MZ03S_1" manufactured by Powdertech Co., Ltd.) was changed from 19.6 parts by mass to 34.3 parts by mass. Except for the above matters, varnish resin composition 12 was prepared in the same manner as in Example 1.

[0246] <Comparative Example 4: Preparation of Varnish Resin Composition 13> In Example 2, 56.4 parts by mass of Fe-Ni-Cr alloy magnetic powder ("AKT-PB-2Cr" manufactured by Mitsubishi Steel Co., Ltd.) was replaced with 56.4 parts by mass of Fe-Ni-Mo alloy magnetic powder ("AKT-78Ni-5Mo" manufactured by Mitsubishi Steel Co., Ltd., alloy with Fe 16.4%, Ni 78.8%, Si 0.2%, Mo 4.5%, average particle size (D 50 ) 5 μm, true density 8.0 g / cm 3 ) Except for the above matters, varnish resin composition 13 was prepared in the same manner as in Example 2.

[0247] <Manufacture of Resin Sheet> A PET film (Toray Industries, Inc.'s "Lumirror R80", thickness 38 μm, softening point 130 °C) that had been subjected to a release treatment with an alkyd resin-based release agent (LINTECH Co., Ltd.'s "AL-5") was prepared as a support. The varnish-like resin compositions (resin varnishes) prepared in the examples and comparative examples were applied onto the support using a die coater so that the thickness of the resin composition layer after drying would be 70 μm, and dried at 90 °C for 5 minutes to obtain a resin sheet.

[0248] <Production of Sheet-like Cured Body> The resin sheet was cut into a 200 mm square. The cut resin sheet (200 mm square) was laminated onto one side of a polyimide film (UBE Industries, Ltd.'s "Upilex 25S", 25 μm thick, 240 mm square) using a batch-type vacuum pressure laminator (Nitto Materials Co., Ltd.'s two-stage buildup laminator "CVP700") so that the resin composition layer would be in contact with the center of the smooth surface of the polyimide film. The lamination was carried out by reducing the pressure for 30 seconds to make the atmospheric pressure 13 hPa or less, and then pressure-bonding at 100 °C and a pressure of 0.74 MPa for 30 seconds. Thereby, a multilayer film having a layer structure of support / resin composition layer / polyimide film was obtained.

[0249] After peeling off the support, the resin composition layer was thermally cured by heating at 190 °C for 90 minutes. Thereafter, the polyimide film was peeled off to obtain a sheet-like cured body of the resin composition.

[0250] <Measurement of Specific Permeability and Loss Factor> The obtained sheet-like cured body was cut to obtain a donut-shaped evaluation sample with an outer diameter of 19.2 mm and an inner diameter of 8.2 mm. The specific permeability (μ') and magnetic loss (μ") of this evaluation sample were measured at a measurement frequency of 20 MHz and a room temperature of 23 °C using a magnetic material test fixture "16454A" manufactured by Keysight Technologies, Inc. and an impedance analyzer "E4991B" manufactured by Keysight Technologies, Inc. The loss factor tanδ was calculated by the formula "tanδ = μ" / μ'".

[0251] The evaluation criteria for the specific permeability (μ') are as follows. 「〇」: The relative magnetic permeability is 23 or more. 「×」: The relative magnetic permeability is less than 23.

[0252] The evaluation criteria for the loss factor (tanδ) are as follows. 「〇」: The loss factor is 0.04 or less. 「×」: The loss factor exceeds 0.04.

[0253]

Table 1

[0254]

Table 2

[0255] In Table 1 and Table 2 above, the "total amount of (A) component and (B) component (mass%)" represents the content with respect to 100 mass% of the non-volatile components in the resin composition, and the "total amount of (A) component and (B) component (volume%)" represents the content with respect to 100 volume% of the non-volatile components in the resin composition. Also, in Table 1 and Table 2 above, the "(Mn + Zn) / Fe value (mass ratio) in the (A) component and (B) component" represents the mass ratio of the total amount of Mn and Zn to the amount of Fe in the entire magnetic powder contained in the (A) component and (B) component.

Explanation of symbols

[0256] 1 Circuit board 10 Core board 11 Support board 12 Metal layer 13 Metal layer 14 Through hole 20 Plating layer 21 Surface around the polished surface 30 Cured product 30a Resin composition 31 Surface of the polished cured product (polished surface) 40 Conductor layer 41 Pattern conductor layer 100 Circuit board 200 Inner layer board 200a First main surface 200b Second main surface 220 Through hole 220a Internal wiring of through hole 240 External terminal 310 Resin sheet 320 First cured product layer 320a Resin composition layer 330 Support 360 Via hole 360a Internal wiring of via hole 400 Coil-shaped conductive structure 420 First conductor layer 420a Land 440 Second conductor layer

Claims

1. A resin composition comprising (A) an iron alloy-based magnetic powder containing Ni, (B) a ferrite-based magnetic powder containing Mn, and (C) a thermosetting resin, wherein component (A) contains an Fe—Ni—Cr alloy magnetic powder, component (B) either contains or does not contain a ferrite-based magnetic powder containing Zn, the mass ratio ((Mn + Zn) / Fe) of the total amount of Mn and Zn to the amount of Fe in the total magnetic powder contained in components (A) and (B) is 0.055 or more and 0.16 or less.

2. The resin composition according to claim 1, wherein the component (B) has an average particle diameter (D) smaller than that of the component (A). ５０ ).

3. The resin composition according to claim 1, wherein component (C) contains (C-1) an epoxy resin.

4. The resin composition according to claim 1, wherein component (C) contains (C-2) a curing agent.

5. The resin composition according to claim 1, further comprising (E) a thermoplastic resin.

6. The resin composition according to claim 1, further comprising (F) a curing accelerator.

7. The resin composition according to claim 1, further comprising (G) a dispersant.

8. The resin composition according to claim 1, wherein the content of Ni contained in component (A) is 33% by mass or more and 65% by mass or less with respect to 100% by mass of component (A).

9. The resin composition according to claim 1, wherein the content of Mn contained in component (B) is 5% by mass or more and 35% by mass or less with respect to 100% by mass of component (B).

10. The resin composition according to claim 1, wherein the amount of component (A) is 30% by volume or more with respect to 100% by volume of the non-volatile components in the resin composition.

11. The resin composition according to claim 1, wherein the amount of component (A) is 40% by mass or more with respect to 100% by mass of the non-volatile components in the resin composition.

12. The resin composition according to claim 1, wherein the amount of component (B) is 10% by volume or more with respect to 100% by volume of the non-volatile components in the resin composition.

13. The resin composition according to claim 1, wherein the amount of component (B) is 10% by mass or more with respect to 100% by mass of the non-volatile components in the resin composition.

14. The resin composition according to claim 1, wherein the total amount of components (A) and (B) is 60% by volume or more with respect to 100% by volume of the non-volatile components in the resin composition.

15. The resin composition according to claim 1, wherein the total amount of components (A) and (B) is 70% by mass or more with respect to 100% by mass of the non-volatile components in the resin composition.

16. The resin composition according to claim 1, which is for hole filling.

17. The cured product of the resin composition according to any one of claims 1 to 16.

18. A magnetic paste containing the resin composition according to any one of claims 1 to 16.

19. Comprising a support and a resin composition layer provided on the support, A resin sheet in which the resin composition layer contains the resin composition according to any one of claims 1 to 16.

20. A circuit board comprising a substrate having holes and a cured product of the resin composition according to any one of claims 1 to 16 filled in the holes.

21. A circuit board comprising a cured product layer containing a cured product of the resin composition according to any one of claims 1 to 16.

22. An inductor substrate comprising the circuit board according to claim 21.

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