JP2022120452A - resin composition - Google Patents

Abstract

To provide a resin composition that can give a magnetic material that can be readily made into paste or a film and also has excellent relative permeability.SOLUTION: A resin composition contains (A) magnetic powder and (B) thermosetting resin. The component (A) includes (A-1) flat magnetic powder and (A-2) spherical magnetic powder, the (A-1) component having an average minor axis length of 1 μm or more.SELECTED DRAWING: None

Description

The present invention relates to a resin composition containing magnetic powder. Furthermore, it relates to a cured product, a resin sheet, a circuit board, and an inductor board obtained using the resin composition.

2. Description of the Related Art As electronic devices have become smaller and thinner in recent years, there is an increasing demand for smaller and thinner printed wiring boards and inductor components (coils) mounted on printed wiring boards. When an inductor component is mounted as a chip component, there is a limit to how thin the printed wiring board can be made.

On the other hand, for example, a method of forming an inductor in the inner layer of a printed wiring board by forming a magnetic layer on the printed board using a resin sheet containing magnetic powder in a resin composition layer is known ( Patent document 1). Further, for example, there is known a method of forming a magnetic layer by screen-printing a paste material containing magnetic powder onto a substrate including wiring (Patent Document 2).

In these embodiments, spherical magnetic powders have been preferably used from the viewpoints of lowering magnetic loss, viscosity, elastic modulus, and the like.

On the other hand, due to the demand for higher performance of inductors, pastes and films containing magnetic powder are also required to have higher magnetic permeability.

WO2018/194099 JP 2020-087939 A

It is conceivable to use flat magnetic powder to increase the magnetic permeability, but the flat magnetic powder is difficult to disperse in the resin, and a paste-like resin composition in which the magnetic powder is uniformly dispersed is used. The problem is that it is difficult to obtain In addition, when a resin composition containing flat magnetic powder is applied to form a film, there is a problem that it is difficult to produce a uniform film, such as many small holes appearing on the film surface.

An object of the present invention is to provide a resin composition that can be easily formed into a paste or a film and that can be used to obtain a magnetic material with excellent relative magnetic permeability.

As a result of intensive research to achieve the above object, the present inventors have unexpectedly found that when specific (A-1) flat magnetic powder and (A-2) spherical magnetic powder are used together, In addition, the present inventors have found that it is possible to easily form a paste and a film, and that excellent relative magnetic permeability can be achieved, and have completed the present invention.

That is, the present invention includes the following contents.
[1] A resin composition containing (A) a magnetic powder and (B) a thermosetting resin,
(A) component contains (A-1) flat magnetic powder and (A-2) spherical magnetic powder,
(A-1) The resin composition, wherein the component has an average minor axis length of 1 μm or more.
[2] The resin composition according to [1] above, wherein component (A-1) has an oblateness of 2 or more and component (A-2) has an oblateness of less than 2.
[3] The resin composition according to [1] or [2] above, wherein component (A-1) has an average particle size of 10 μm to 100 μm.
[4] The resin composition according to any one of [1] to [3] above, wherein component (A-2) has an average particle size of 0.1 μm to 40 μm.
[5] The above [1], wherein the mass ratio of component (A-1) to component (A-2) ((A-1) component/(A-2) component) is 0.4 to 2.3 The resin composition according to any one of -[4].
[6] Any one of [1] to [5] above, wherein the content of component (A) is 25% by volume to 75% by volume when the non-volatile component in the resin composition is 100% by volume. of the resin composition.
[7] Any one of [1] to [6] above, wherein the content of component (A) is 70% by mass to 96% by mass when the non-volatile component in the resin composition is 100% by mass. of the resin composition.
[8] The resin composition according to any one of [1] to [7] above, wherein component (B) contains (B-1) an epoxy resin.
[9] The resin composition according to any one of [1] to [8] above, further comprising (C) a curing accelerator.
[10] The resin according to any one of [1] to [9] above, wherein the cured product of the resin composition has a relative magnetic permeability (μ') of 11 or more when measured at a measurement frequency of 10 MHz and 23°C. Composition.
[11] The resin composition according to any one of [1] to [10] above, which has a viscosity of 0.05 Pa·s to 1500 Pa·s at 25°C.
[12] A resin sheet comprising a support and a resin composition layer formed of the resin composition according to any one of [1] to [11] provided on the support.
[13] A cured product of the resin composition according to any one of [1] to [11] above.
[14] A circuit board comprising a substrate having through holes, and a cured product of the resin composition according to any one of [1] to [11] filled in the through holes.
[15] A circuit board comprising a cured product layer which is a cured product of the resin composition according to any one of [1] to [11] above.
[16] An inductor substrate including the circuit substrate according to [14] or [15] above.

According to the resin composition of the present invention, it is possible to obtain a magnetic material that can be easily made into a paste or a film and has excellent relative magnetic permeability.

FIG. 1 is a schematic cross-sectional view of a core board as an example of the method for manufacturing a circuit board according to the first embodiment. FIG. 2 is a schematic cross-sectional view of a core substrate having through holes formed thereon as an example of the method of manufacturing a circuit board according to the first embodiment. FIG. 3 is a schematic cross-sectional view showing a state of a core substrate having a plated layer formed in a through hole as an example of the method of manufacturing a circuit board according to the first embodiment. FIG. 4 is a schematic cross-sectional view showing a state of a core substrate in which through holes are filled with a resin composition as an example of the method for manufacturing a circuit board according to the first embodiment. FIG. 5 is a schematic cross-sectional view showing a state of a core substrate obtained by thermally curing the filled resin composition as an example of the method for manufacturing a circuit board according to the first embodiment. FIG. 6 is a schematic cross-sectional view showing a state of a core substrate after polishing a cured product as an example of the method for manufacturing a circuit board according to the first embodiment. FIG. 7 is a schematic cross-sectional view showing a state of a core substrate in which a conductor layer is formed on a polished surface as an example of the method of manufacturing a circuit board according to the first embodiment. FIG. 8 is a schematic cross-sectional view showing a state of a core substrate on which a pattern conductor layer is formed as an example of the method of manufacturing a circuit board according to the first embodiment. FIG. 9 is a schematic cross-sectional view for explaining the step (A) included in one example of the method for manufacturing a circuit board according to the second embodiment. FIG. 10 is a schematic cross-sectional view for explaining the step (A) included in one example of the method for manufacturing a circuit board according to the second embodiment. FIG. 11 is a schematic cross-sectional view for explaining the step (B) included in one example of the method for manufacturing a circuit board according to the second embodiment. FIG. 12 is a schematic cross-sectional view for explaining the step (D) included in one example of the method for manufacturing a circuit board according to the second embodiment. FIG. 13 is a schematic plan view of an inductor component including a circuit board obtained by the circuit board manufacturing method of the second embodiment as an example, viewed from one of its thickness directions. FIG. 14 is a schematic diagram showing a cut end surface of an inductor component including a circuit board obtained by the circuit board manufacturing method of the second embodiment cut at the position indicated by the dashed-dotted line II-II shown in FIG. 13 as an example. It is a diagram. FIG. 15 is a schematic plan view for explaining the configuration of the first conductor layer of the inductor component including the circuit board obtained by the circuit board manufacturing method of the second embodiment as an example. FIG. 16 is a schematic diagram of magnetic powder particles for explaining the relationship between the thickness of the magnetic powder, the minor axis length of the magnetic powder, and the major axis length of the magnetic powder.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail with reference to its preferred embodiments. However, the present invention is not limited to the following embodiments and examples, and can be arbitrarily modified without departing from the scope of the claims of the present invention and their equivalents.

<Resin composition>
The resin composition of the present invention comprises (A) magnetic powder and (B) a thermosetting resin, wherein (A) magnetic powder comprises (A-1) flat magnetic powder and (A- 2) It contains spherical magnetic powder, and (A-1) the flat magnetic powder has an average minor axis length of 1 μm or more. By using such a resin composition, it is possible to obtain a magnetic material that can be easily formed into a paste or a film and has excellent relative magnetic permeability.

The resin composition of the present invention may further contain optional components in addition to (A) the magnetic powder and (B) the thermosetting resin. Examples of optional components include (C) a curing accelerator, (D) a thermoplastic resin, (E) a dispersant, (F) other additives, and (G) an organic solvent. Each component contained in the resin composition will be described in detail below.

<(A) Magnetic powder>
The resin composition of the present invention contains (A) magnetic powder. (A) The magnetic powder can impart magnetism to the resin composition. (A) The magnetic powder is contained in the form of particles in the resin composition of the present invention. In the resin composition of the present invention, (A) magnetic powder includes both (A-1) flat magnetic powder and (A-2) spherical magnetic powder.

<(A-1) Flat magnetic powder>
In the resin composition of the present invention, (A) magnetic powder includes (A-1) flat magnetic powder. (A-1) Flat magnetic powder The magnetic powder may be used singly or in combination of two or more.

(A-1) The flat magnetic powder may be soft magnetic powder or hard magnetic powder. A body is preferred. (A-1) The flat magnetic powder may be, for example, magnetic metal powder, magnetic metal oxide powder, or the like.

Examples of magnetic metal oxide powder include ferrite powder and iron oxide powder.

The ferrite powder may be hard ferrite powder or soft ferrite powder, but in one embodiment, soft ferrite powder is preferable from the viewpoint of increasing the relative magnetic permeability. The ferrite powder may be spinel ferrite powder, hexagonal ferrite powder, or garnet ferrite powder. is preferred. The ferrite powder may be single crystal ferrite powder or polycrystalline ferrite powder.

The ferrite powder contains at least one element selected from, for example, Mn, Zn, Mg, Sr, Ni, Cu, Ba, Co, Ca, Al, Li, Ti, Pb, Cd, etc., in addition to Fe. obtain. In one embodiment, the ferrite powder preferably contains Fe and at least one element selected from Mn, Zn, Mg, Sr, and Ni.

Examples of ferrite powder include Fe—Mn ferrite powder, Mg—Zn ferrite powder, Mn ferrite powder, Mn—Zn ferrite powder, Mn—Mg ferrite powder, and Cu—Zn ferrite powder. Ferrite powder, Mg-Sr ferrite powder, Mn-Mg-Sr ferrite powder, Ni-Zn ferrite powder, Ni-Zn-Cu ferrite powder, Ba-Zn ferrite powder, Ba- Mg-based ferrite powder, Ba--Ni-based ferrite powder, Ba--Co-based ferrite powder, Ba--Ni--Co-based ferrite powder, Y-based ferrite powder, and the like can be mentioned.

Examples of the iron oxide powder include, but are not particularly limited to, iron (III) oxide powder, triiron tetraoxide powder, and the like.

The magnetic metal powder preferably contains at least one element selected from Fe, Co, and Ni. The content of Fe, Co, and Ni in the magnetic metal powder can be preferably 50% by mass or more, more preferably 60% by mass or more, and still more preferably 70% by mass or more. The magnetic metal powder preferably contains an element selected from, for example, Si, Al, Cr, Mo, Cu, etc. in addition to the element selected from Fe, Co, and Ni.

The magnetic metal powder is not particularly limited, but for example, pure iron powder; Fe—Si alloy powder, Fe—Si—Al alloy powder, Fe—Cr alloy powder, Fe -Si--Cr alloy powder, Fe--Ni--Cr alloy powder, Fe--Cr--Al alloy powder, Fe--Ni alloy powder, Fe--Ni--Mo alloy powder, Fe--Ni -Crystalline or amorphous magnetic alloy powder such as Mo-Cu alloy powder, Fe-Co alloy powder, Fe-Ni-Co alloy powder, Co-based amorphous alloy powder, etc. .

(A-1) The flat magnetic powder preferably contains magnetic metal powder, more preferably magnetic alloy powder, and Fe--Si--Al alloy powder and Fe--Si--Cr-based powder. It is more preferable to contain magnetic alloy powder selected from alloy powders, and it is particularly preferable to contain Fe--Si--Al alloy powder.

(A-1) The 10% particle size (D ₁₀ ) of the flat magnetic powder is not particularly limited, but is preferably 0.5 μm to 50 μm, more preferably 1 to 40 μm, and still more preferably 2 μm. to 35 μm, particularly preferably 3 to 30 μm.

(A-1) The average particle diameter (D ₅₀ ) of the flat magnetic powder is preferably 100 μm or less, more preferably 60 μm or less, even more preferably 50 μm or less, and particularly preferably 40 μm or less. (A-1) The lower limit of the average particle size (D ₅₀ ) of the flat magnetic powder is preferably 10 μm or more, more preferably 20 μm or more, and still more preferably 25 μm or more, from the viewpoint of obtaining the effects of the invention more remarkably. , particularly preferably 30 μm or more.

(A-1) The 90% particle size (D ₉₀ ) of the flat magnetic powder is not particularly limited, but is preferably 30 μm to 200 μm, more preferably 40 to 150 μm, still more preferably 50 to 140 μm. , particularly preferably from 60 to 130 μm.

The 10% particle size (D ₁₀ ), average particle size (D ₅₀ ), and 90% particle size (D ₉₀ ) of the magnetic powder were each measured and measured by a laser diffraction/scattering method based on Mie scattering theory. can be calculated. Specifically, the particle size distribution of the magnetic powder was created on a volume basis using a laser diffraction scattering type particle size distribution measuring device, and the 10% particle size (D ₁₀ ), 50% particle size (average particle size) (D ₅₀ ), and the 90% particle size (D ₉₀ ) can be calculated. As a measurement sample, a magnetic powder dispersed in pure water by ultrasonic waves can be preferably used. As the laser diffraction/scattering type particle size distribution analyzer, “MT3000II” manufactured by Microtrack Bell, “LA-960” manufactured by Horiba, “SALD-2200” manufactured by Shimadzu, etc. can be used.

(A-1) The average thickness of the flat magnetic powder is preferably 0.05 μm or more, more preferably 0.1 μm or more, and still more preferably 0.5 μm or more, from the viewpoint of further improving magnetic permeability. The upper limit is preferably 40 µm or less, more preferably 30 µm or less, and even more preferably 20 µm or less, from the viewpoint of further improving the filling property. The average thickness of the magnetic powder is the average thickness of the magnetic powder. The average value of the thickness of the magnetic powder is obtained by measuring the thickness of, for example, 50 magnetic powders based on a scanning electron microscope image, and based on the maximum value Ym and the minimum value Yn, (Ym + Yn) / 2. It can be a calculated value. The thickness of the magnetic powder is the same as the longest axis when a line segment connecting two points having the longest distance between each other among arbitrary two points on the outer surface of the magnetic powder particle A is taken as the longest axis. A rectangular parallelepiped B having the longest side X parallel to the longest longitudinal axis, and the shortest side perpendicular to the longest side X in the rectangular parallelepiped B when drawing the rectangular parallelepiped B with the smallest volume circumscribing the outer surface of the magnetic powder particles A It refers to the length of Y (see FIG. 16).

(A-1) The average minor axis length of the flat magnetic powder is determined from the viewpoint of keeping the viscosity low and the desired magnetic permeability when making the resin composition into a paste or preparing a varnish for film formation. From the standpoint of obtaining a better magnetic permeability, it is preferably 3 µm or more, more preferably 5 µm or more, even more preferably 8 µm or more, and particularly preferably 10 µm or more, from the viewpoint of further improving the magnetic permeability. From the viewpoint of further improvement, the thickness is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 30 μm or less. The average minor axis length of the magnetic powder is the average value of the minor axis lengths of the magnetic powder. The average value of the minor axis lengths of the magnetic powder can be, for example, the number average when measuring the minor axis lengths of, for example, 50 magnetic particles based on scanning electron microscope images. The minor axis length of the magnetic powder is defined as the longest axis when a line segment connecting two points having the longest distance between each other among arbitrary two points on the outer surface of the magnetic powder particle A is taken as the longest axis. A rectangular parallelepiped B having a longest side X parallel to the longest axis of the same length as the longest side X and the longest side of the rectangular parallelepiped B when drawing a rectangular parallelepiped B with a minimum volume that circumscribes the outer surface of the magnetic powder particle A It refers to the length of the shortest side Y perpendicular to X and the length of the third side Z perpendicular to both (see FIG. 16).

(A-1) The oblateness of the flat magnetic powder is preferably 2 or more, more preferably 3 or more, still more preferably 5 or more, and particularly preferably 15 or more, from the viewpoint of further improving magnetic permeability, The upper limit is preferably 1,000 or less, more preferably 650 or less, even more preferably 600 or less, and particularly preferably 550 or less, from the viewpoint of further improving filling properties. The oblateness of the magnetic powder is a value calculated by dividing the "average major axis length (μm) of the magnetic powder" by the "average thickness (μm) of the magnetic powder". The average major axis length of the magnetic powder is the average value of the major axis lengths of the magnetic powder. The average value of the major axis lengths of the magnetic powder can be, for example, the number average when the major axis lengths of 50 magnetic powders are measured based on scanning electron microscope images. The major axis length of the magnetic powder is the length of the line segment connecting two points with the longest mutual distance among arbitrary two points on the outer surface of the magnetic powder particle A (that is, The length of the longest side X in the illustrated rectangular parallelepiped B).

(A-1) The aspect ratio of the flat magnetic powder is preferably 1.0 or more, more preferably 1.2 or more, and still more preferably 1.5 or more, from the viewpoint of further improving magnetic permeability, The upper limit is preferably 6.0 or less, more preferably 5.0 or less, still more preferably 4.0 or less, still more preferably 3.5 or less, and particularly preferably 3.5 or less, from the viewpoint of further improving filling properties. 0 or less. The aspect ratio of the magnetic powder is a value calculated by dividing the "average major axis length (μm) of the magnetic powder" by the "average minor axis length (μm) of the magnetic powder".

(A-1) The tap density of the flat magnetic powder is preferably 0.5 to 4.0 g/cm ³ , more preferably 0.8 to 4.0 g/cm, from the viewpoint of further improving the filling property. ³ , more preferably 1.0 to 4.0 g/cm ³ , still more preferably 1.5 to 4.0 g/cm ³ , particularly preferably 1.7 to 4.0 g/cm ³ . The tap density may be a value obtained by measuring according to JIS Z2512.

(A-1) The true specific gravity of the flat magnetic powder is not particularly limited, but can be, for example, 4 to 10 g/cm ³ .

(A-1) As the flat magnetic powder, commercially available magnetic powder can be used. (A-1) Specific examples of commercial products of flat magnetic powder include “PST-4” and “FME3D-AH” manufactured by Sanyo Special Steel Co., Ltd., and “JEMK S” and “JEMK H” manufactured by Kinseimatec. etc. These may be used individually by 1 type, or may use 2 or more types together.

The content (% by volume) of the flat magnetic powder (A-1) further improves the magnetic permeability, and (A-1) the flat magnetic powder and (A-2) the spherical magnetic powder From the viewpoint of further improving the mixing of and keeping the viscosity lower, when the non-volatile component in the resin composition is 100% by volume, it is preferably 1% by volume or more, more preferably 5% by volume or more, and still more preferably 10% by volume. % or more, still more preferably 12% by volume or more, particularly preferably 15% by volume or more, and the upper limit is preferably 70% by volume or less, more preferably 60% by volume or less, further preferably 55% by volume or less, and further More preferably 50% by volume or less, particularly preferably 45% by volume or less.

(A-1) The content (% by mass) of the flat magnetic powder further improves the magnetic permeability, and (A-1) the flat magnetic powder and (A-2) the spherical magnetic powder From the viewpoint of further improving the mixing of and keeping the viscosity lower, when the non-volatile component in the resin composition is 100% by mass, it is preferably 10% by mass or more, more preferably 20% by mass or more, and still more preferably 25% by mass. % or more, particularly preferably 30 mass % or more, and the upper limit is preferably 80 mass % or less, more preferably 70 mass % or less, still more preferably 65 mass % or less, and particularly preferably 60 mass % or less.

<(A-2) Spherical magnetic powder>
In the resin composition of the present invention, (A) magnetic powder includes (A-2) spherical magnetic powder. (A-2) The spherical magnetic powder may be used singly or in combination of two or more.

(A-2) The spherical magnetic powder may be either soft magnetic powder or hard magnetic powder. is preferably (A-2) The spherical magnetic powder may be, for example, magnetic metal oxide powder, magnetic metal powder, or the like. Examples of the magnetic metal powder and the magnetic metal oxide powder are the same as those given in the description of (A-1) flat magnetic powder, except that the external shape of each powder is different. are listed.

(A-2) In one embodiment, the spherical magnetic powder preferably contains magnetic metal powder, more preferably magnetic alloy powder, Fe—Si—Al alloy powder and Fe— It is more preferable to contain magnetic alloy powder selected from Si--Cr alloy powders, and it is particularly preferable to contain Fe--Si--Cr alloy powder.

The Fe--Si--Cr alloy powder contains Fe, Si and Cr. The amount of Fe in the Fe—Si—Cr alloy powder is preferably 75% to 99% by mass, more preferably 80% to 97% by mass, and particularly preferably 85% to 95% by mass. The amount of Si in the Fe—Si—Cr alloy powder is preferably 2.0% by mass to 15.0% by mass, more preferably 3.5% by mass to 11.0% by mass, and particularly preferably 5.0% by mass. % to 9.5% by mass. The amount of Cr in the Fe—Si—Cr alloy powder is preferably 0.1% by mass to 10.0% by mass, more preferably 0.5% by mass to 8.0% by mass, and particularly preferably 1.0% by mass. % to 6.0% by mass. The Fe--Si--Cr alloy powder may contain metallic elements and semi-metallic elements other than Fe, Si and Cr.

(A-2) In one embodiment, the spherical magnetic powder preferably contains magnetic metal oxide powder, more preferably ferrite powder, Mn-based ferrite powder, and Mn—Zn-based It is more preferable to contain ferrite powder selected from ferrite powder, and it is particularly preferable to contain Mn-based ferrite powder.

Mn-based ferrite powder contains Fe and Mn. The amount of Fe in the Mn-based ferrite powder is preferably 40% by mass or more, more preferably 45% by mass or more, and particularly preferably It is 50% by mass or more, preferably 75% by mass or less, more preferably 70% by mass or less, and particularly preferably 65% by mass or less. The amount of Mn in the single crystal Mn-based ferrite powder is preferably 3% by mass or more, more preferably 5% by mass or more, and particularly preferably It is 7% by mass or more, preferably 40% by mass or less, more preferably 35% by mass or less, and particularly preferably 30% by mass or less. The Mn-based ferrite powder may contain elements other than Fe and Mn, such as metal elements and metalloid elements. The amount of metal elements and metalloid elements other than Fe and Mn in the Mn-based ferrite powder is preferably less than 1% by mass, more preferably 0%, when all elements including O contained in the ferrite are taken as 100% by mass. less than 0.7% by weight, particularly preferably less than 0.5% by weight.

(A-2) In one embodiment, the spherical magnetic powder preferably contains magnetic metal powder and magnetic metal oxide powder, more preferably magnetic alloy powder and ferrite powder, and Fe - magnetic alloy powder selected from Si-Al alloy powder and Fe-Si-Cr alloy powder, and ferrite powder selected from Mn-based ferrite powder and Mn-Zn-based ferrite powder is more preferable, and it is particularly preferable to contain Fe—Si—Cr alloy powder and Mn-based ferrite powder.

(A-2) The 10% particle diameter (D ₁₀ ) of the spherical magnetic powder is not particularly limited, but is preferably 0.005 μm to 25 μm, more preferably 0.01 to 20 μm, and particularly preferably It can be from 0.03 to 15 μm.

(A-2) The average particle size (D ₅₀ ) of the spherical magnetic powder is preferably 40 μm or less, more preferably 30 μm or less, even more preferably 20 μm or less, and particularly preferably 12 μm, from the viewpoint of keeping the magnetic loss lower. Although the lower limit is not particularly limited, it is preferably 0.01 μm or more, more preferably 0.05 μm or more, still more preferably 0.08 μm or more, and particularly preferably 0.1 μm or more. .

(A-2) The 90% particle diameter (D ₉₀ ) of the spherical magnetic powder is not particularly limited, but is preferably 0.1 μm to 50 μm, more preferably 0.5 to 30 μm, and still more preferably It can be from 0.8 to 25 μm, particularly preferably from 1 to 20 μm.

(A-2) The average thickness of the spherical magnetic powder is preferably 40 μm or less, more preferably 30 μm or less, even more preferably 20 μm or less, and particularly preferably 12 μm or less, from the viewpoint of keeping the magnetic loss lower. Although the lower limit is not particularly limited, it is preferably 0.01 μm or more, more preferably 0.05 μm or more, still more preferably 0.08 μm or more, and particularly preferably 0.10 μm or more.

(A-2) The oblateness of the spherical magnetic powder is preferably less than 2, more preferably 1.5 or less, still more preferably 1.3 or less, and particularly preferably 1.2 or less. , 1, etc.

(A-2) The aspect ratio of the spherical magnetic powder is preferably 2 or less, more preferably 1.5 or less, still more preferably 1.3 or less, and particularly preferably 1.2 or less. , 1, etc.

(A-2) The true specific gravity of the spherical magnetic powder can be, for example, 4 to 10 g/cm ³ .

(A-2) The specific surface area of the spherical magnetic powder is not particularly limited, but is preferably 0.05 m ² /g or more, more preferably 0.1 m ² /g or more, and still more preferably 0.1 m 2 /g or more. 3 m ² /g or more. Also, it is preferably 30 m ² /g or less, more preferably 20 m ² /g or less, still more preferably 15 m ² /g or less. The specific surface area of magnetic powder can be measured by the BET method.

(A-2) A commercially available product can be used as the spherical magnetic powder. (A-2) Commercial products of spherical magnetic powder include, for example, "M05S" and "M001" manufactured by Powdertech; "PST-S" manufactured by Sanyo Special Steel; and "AW2-08" manufactured by Epson Atmix. ”, “AW2-08PF20F”, “AW2-08PF10F”, “AW2-08PF3F”, “Fe-3.5Si-4.5CrPF20F”, “Fe-50NiPF20F”, “Fe-80Ni-4MoPF20F”; manufactured by JFE Chemical Co., Ltd. "LD-M", "LD-MH", "KNI-106", "KNI-106GSM", "KNI-106GS", "KNI-109", "KNI-109GSM", "KNI-109GS"; Company "KNS-415", "BSF-547", "BSF-029", "BSN-125", "BSN-125", "BSN-714", "BSN-828", "S-1281", "S-1641", "S-1651", "S-1470", "S-1511", "S-2430"; "JR09P2" manufactured by Japan Heavy Chemical Industries, Ltd.; "Nanotek" manufactured by CIK Nanotech; "JEMK-S", "JEMK-H" manufactured by ALDRICH Co., Ltd. "Yttrium iron oxide". (A-2) The spherical magnetic powder may be used singly or in combination of two or more.

(A-2) The content (% by volume) of the spherical magnetic powder improves the mixing of the (A-1) flat magnetic powder and (A-2) the spherical magnetic powder, and increases the viscosity. From the viewpoint of keeping the vol. % or more, 20 volume % or more, or 25 volume % or more, and the upper limit is preferably 70 volume % or less, more preferably 60 volume % or less, even more preferably 55 volume % or less, and particularly preferably 50 volume % or less. is.

(A-2) The content (% by mass) of the spherical magnetic powder improves the mixing of (A-1) the flat magnetic powder and (A-2) the spherical magnetic powder, and increases the viscosity. from the viewpoint of lowering the non-volatile component in the resin composition to 100% by mass, preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, and even more preferably 40% by mass. % by mass or more, particularly preferably 50% by mass or more, and the upper limit is preferably 85% by mass or less, more preferably 80% by mass or less, even more preferably 75% by mass or less, and even more preferably 70% by mass or less, Especially preferably, it is 65% by mass or less.

The mass ratio of (A-1) flat magnetic powder to (A-2) spherical magnetic powder ((A-1) component/(A-2) component) is, for example, 0.05 or more, 0.05 or more. It can be 1 or more, and from the viewpoint of further improving magnetic permeability, it is preferably 0.2 or more, more preferably 0.3 or more, still more preferably 0.4 or more, and particularly preferably 0.5 or more. In addition, the upper limit may be, for example, 50.0 or less, 10.0 or less, etc. From the viewpoint of keeping the viscosity lower, it is preferably 3.0 or less, more preferably 2.7 or less, and still more preferably 2.5. Below, more preferably 2.3 or less, particularly preferably 2.2 or less.

(A) The content (% by volume) of the magnetic powder is not particularly limited, but from the viewpoint of further improving the magnetic permeability, when the non-volatile component in the resin composition is 100% by volume, preferably It is 20% by volume or more, more preferably 25% by volume or more, still more preferably 30% by volume or more, even more preferably 40% by volume or more, and particularly preferably 45% by volume or more. The upper limit is not particularly limited, but when the nonvolatile component in the resin composition is 100% by volume, it is preferably 85% by volume or less, more preferably 82% by volume or less, and still more preferably 79% by volume. % or less, particularly preferably 75 volume % or less.

(A) The content (% by mass) of the magnetic powder is not particularly limited, but from the viewpoint of further improving the magnetic permeability, when the non-volatile component in the resin composition is 100% by mass, it is preferably 50% by mass or more, more preferably 60% by mass or more and 70% by mass or more, still more preferably 75% by mass or more and 80% by mass or more, and particularly preferably 85% by mass or more and 88% by mass or more. The upper limit is not particularly limited, but when the nonvolatile component in the resin composition is 100% by mass, it is preferably 97% by mass or less, more preferably 96% by mass or less, and particularly preferably 95% by mass. % or less.

<(B) Thermosetting resin>
The resin composition of the present invention contains (B) a thermosetting resin. (B) Thermosetting resins include, for example, epoxy resins, epoxy acrylate resins, urethane acrylate resins, urethane resins, cyanate resins, polyimide resins, benzoxazine resins, unsaturated polyester resins, phenol resins, melamine resins, silicone resins, etc. and includes curing agents (eg, epoxy curing agents) that react with them.

(B) The content (% by mass) of the thermosetting resin is not particularly limited, but from the viewpoint of obtaining the effect of the invention more remarkably, when the non-volatile component in the resin composition is 100% by mass , preferably 0.1% by mass or more, more preferably 1% by mass or more, still more preferably 3% by mass or more, and particularly preferably 4% by mass or more. In addition, from the viewpoint of obtaining the effect of the invention more remarkably, the upper limit is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 100% by mass of nonvolatile components in the resin composition. 20% by mass or less, particularly preferably 17% by mass or less.

<(B-1) Epoxy resin>
The resin composition of the present invention preferably contains (B-1) epoxy resin as (B) thermosetting resin. (B-1) Epoxy resin means a resin having an epoxy group.

(B-1) Epoxy resins include, for example, bixylenol 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, tris Phenol type epoxy resin, naphthol novolak type epoxy resin, phenol novolak type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, glycidylamine type epoxy resin, glycidyl ester type Epoxy resins, cresol novolak type epoxy resins, phenol aralkyl type epoxy resins, biphenyl type epoxy resins, linear aliphatic epoxy resins, epoxy resins having a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spirocyclic epoxy resins Resin, cyclohexane-type epoxy resin, cyclohexanedimethanol-type epoxy resin, naphthylene ether-type epoxy resin, trimethylol-type epoxy resin, tetraphenylethane-type epoxy resin, isocyanurate-type epoxy resin, phenolphthalimidine-type epoxy resin, phenol phthalein-type epoxy resin and the like. (B-1) Epoxy resins may be used singly or in combination of two or more.

The resin composition preferably contains an epoxy resin having two or more epoxy groups in one molecule as the (B-1) epoxy resin. (B-1) 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, relative to 100% by mass of the non-volatile components of the epoxy resin, Particularly preferably, it is 70% by mass or more.

Epoxy resins include liquid epoxy resins at a temperature of 20° C. (hereinafter sometimes referred to as “liquid epoxy resins”) and solid epoxy resins at a temperature of 20° C. (hereinafter sometimes referred to as “solid epoxy resins”). ). As the epoxy resin, the resin composition of the present invention may contain only a liquid epoxy resin, may contain only a solid epoxy resin, or may contain a combination of a liquid epoxy resin and a solid epoxy resin. You can stay. The resin composition of the present invention preferably contains a liquid epoxy resin as the epoxy resin.

A liquid epoxy resin having two or more epoxy groups in one molecule is preferable as the liquid epoxy resin.

Liquid epoxy resins include glycyrrol type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, naphthalene type epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, phenol novolac type epoxy resins. Resins, alicyclic epoxy resins having an ester skeleton, cyclohexanedimethanol-type epoxy resins, cycloaliphatic glycidyl ethers, and epoxy resins having a butadiene structure are preferred, and glycyrrol-type epoxy resins, cycloaliphatic glycidyl ethers, bisphenol A-type epoxy resins are preferred. Resins and bisphenol F type epoxy resins are more preferred.

Specific examples of liquid epoxy resins include "EX-992L" manufactured by Nagase ChemteX Corporation, "YX7400" manufactured by Mitsubishi Chemical Corporation, "HP4032", "HP4032D", and "HP4032SS" manufactured by DIC Corporation (naphthalene type epoxy resin ); Mitsubishi Chemical "828US", "828EL", "jER828EL", "825", "Epicoat 828EL" (bisphenol A type epoxy resin); Mitsubishi Chemical "jER807", "1750" (bisphenol F type epoxy resin); "jER152" (phenol novolak type epoxy resin) manufactured by Mitsubishi Chemical; "630", "630LSD", "604" (glycidylamine type epoxy resin) manufactured by Mitsubishi Chemical; ED-523T” (glycirrol type epoxy resin); ADEKA “EP-3950L”, “EP-3980S” (glycidylamine type epoxy resin); ADEKA “EP-4088S” (dicyclopentadiene type epoxy resin ); "ZX1059" manufactured by Nippon Steel Chemical & Materials Co., Ltd. (mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin); "EX-721" manufactured by Nagase ChemteX Corporation (glycidyl ester type epoxy resin); Nagase "EX-991L" manufactured by Chemtex (epoxy resin containing alkyleneoxy skeleton and butadiene skeleton); "Celoxide 2021P" manufactured by Daicel (alicyclic epoxy resin having an ester skeleton); "PB-3600" manufactured by Daicel ”, “JP-100” and “JP-200” manufactured by Nippon Soda Co., Ltd. (epoxy resin having a butadiene structure); epoxy resin); "EG-280" (fluorene structure-containing epoxy resin) manufactured by Osaka Gas Chemicals; "EX-201" (cycloaliphatic glycidyl ether) manufactured by Nagase ChemteX.

The solid epoxy resin is preferably a solid epoxy resin having 3 or more epoxy groups per molecule, more preferably an aromatic solid epoxy resin having 3 or more epoxy groups per molecule.

Solid epoxy resins include bixylenol type epoxy resin, naphthalene type epoxy resin, naphthalene type tetrafunctional epoxy resin, naphthol novolak type epoxy resin, cresol novolak type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, Naphthol type epoxy resin, biphenyl type epoxy resin, naphthylene ether type epoxy resin, anthracene type epoxy resin, bisphenol A type epoxy resin, bisphenol AF type epoxy resin, phenol aralkyl type epoxy resin, tetraphenylethane type epoxy resin, phenol phthaloid A mijin-type epoxy resin and a phenolphthalein-type epoxy resin are preferred.

Specific examples of solid epoxy resins include "HP4032H" (naphthalene-type epoxy resin) manufactured by DIC; "HP-4700" and "HP-4710" (naphthalene-type tetrafunctional epoxy resin) manufactured by DIC; "N-690" (cresol novolac type epoxy resin) manufactured by DIC Corporation; "N-695" (cresol novolak type epoxy resin) manufactured by DIC Corporation; "HP-7200", "HP-7200HH", "HP -7200H", "HP-7200L" (dicyclopentadiene type epoxy resin); DIC's "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S" ", "HP6000" (naphthylene ether type epoxy resin); Nippon Kayaku "EPPN-502H" (trisphenol type epoxy resin); Nippon Kayaku "NC7000L" (naphthol novolac type epoxy resin); "NC3000H", "NC3000", "NC3000L", "NC3000FH", "NC3100" (biphenyl type epoxy resin) manufactured by Nippon Kayaku; epoxy resin); "ESN485" (naphthol type epoxy resin) manufactured by Nippon Steel Chemical &Materials; "ESN375" (dihydroxynaphthalene type epoxy resin) manufactured by Nippon Steel Chemical &Materials; "YX4000H" manufactured by Mitsubishi Chemical, "YX4000", "YX4000HK", "YL7890" (bixylenol type epoxy resin); "YL6121" (biphenyl type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX8800" (anthracene type epoxy resin) manufactured by Mitsubishi Chemical Corporation; Mitsubishi "YX7700" (phenol aralkyl epoxy resin) manufactured by Chemical Company; "PG-100" and "CG-500" manufactured by Osaka Gas Chemicals; "YL7760" manufactured by Mitsubishi Chemical (bisphenol AF type epoxy resin); Mitsubishi Chemical Company "YL7800" (fluorene type epoxy resin); Mitsubishi Chemical Corporation "jER1010" (bisphenol A type epoxy resin); Mitsubishi Chemical Corporation "jER1031S" (tetraphenylethane type epoxy resin); Nippon Kayaku "WHR991S" (phenol phthalimidine type epoxy resin) manufactured by Co., Ltd., and the like. These may be used individually by 1 type, and may be used in combination of 2 or more types.

(B-1) The epoxy equivalent of the epoxy resin is preferably 50 g/eq. ~5,000g/eq. , more preferably 60 g/eq. ~2,000 g/eq. , more preferably 70 g/eq. ~1,000g/eq. , even more preferably 80 g/eq. ~500 g/eq. is. Epoxy equivalent weight is the mass of resin per equivalent of epoxy groups. This epoxy equivalent can be measured according to JIS K7236.

(B-1) The weight average molecular weight (Mw) of the epoxy resin is preferably 100 to 5,000, more preferably 250 to 3,000, still more preferably 400 to 1,500. The weight average molecular weight of the resin can be measured as a polystyrene-equivalent value by a gel permeation chromatography (GPC) method.

(B-1) The content (% by mass) of the epoxy resin is not particularly limited, but from the viewpoint of obtaining the effect of the invention more remarkably, when the non-volatile component in the resin composition is 100% by mass. , preferably 0.1% by mass or more, more preferably 1% by mass or more, still more preferably 2% by mass or more, and particularly preferably 3% by mass or more. In addition, from the viewpoint of obtaining the effect of the invention more remarkably, the upper limit is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 100% by mass of nonvolatile components in the resin composition. 20% by mass or less, particularly preferably 15% by mass or less.

<(B-2) Epoxy curing agent>
When the resin composition of the present invention contains (B-1) epoxy resin as (B) thermosetting resin, it may contain (B-2) epoxy curing agent as an optional component. (B-2) Epoxy curing agent has a function of reacting with (B-1) epoxy resin to cure the resin composition.

(B-2) Epoxy curing agents are not particularly limited, but examples include active ester curing agents, phenol curing agents, carbodiimide curing agents, acid anhydride curing agents, amine curing agents, Examples include benzoxazine-based curing agents, cyanate ester-based curing agents, and thiol-based curing agents. (B-2) The epoxy curing agent preferably contains an epoxy curing agent selected from phenolic curing agents and active ester curing agents, and particularly preferably contains a phenolic curing agent.

Active ester curing agents generally have two or more highly reactive ester groups per molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds. A compound is preferably used. The active ester compound is preferably obtained by a condensation reaction between a carboxylic acid compound and/or a thiocarboxylic acid compound and a hydroxy compound and/or a thiol compound. In particular, from the viewpoint of improving heat resistance, an active ester compound obtained from a carboxylic acid compound and a hydroxy compound is preferred, and an active ester compound obtained from a carboxylic acid compound and a phenol compound and/or a naphthol compound is more preferred. Examples of carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. Examples of phenol compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalin, 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, phloroglucine, Benzenetriol, dicyclopentadiene-type diphenol compound, phenol novolak, and the like. Here, the term "dicyclopentadiene-type diphenol compound" refers to a diphenol compound obtained by condensing one molecule of dicyclopentadiene with two molecules of phenol.

Specific examples of active ester curing agents include dicyclopentadiene-type active ester compounds, naphthalene-type active ester compounds containing a naphthalene structure, active ester compounds containing acetylated phenol novolacs, and active ester compounds containing benzoylated phenol novolacs. Ester compounds are preferred, among which at least one selected from dicyclopentadiene-type active ester compounds and naphthalene-type active ester compounds is more preferred, and dicyclopentadiene-type active ester compounds are even more preferred. As the dicyclopentadiene-type active ester compound, an active ester compound containing a dicyclopentadiene-type diphenol structure is preferable.

Commercially available active ester curing agents include "EXB9451", "EXB9460", "EXB9460S", "EXB-8000L", and "EXB-8000L-65M" as active ester compounds containing a dicyclopentadiene type diphenol structure. , "EXB-8000L-65TM", "HPC-8000L-65TM", "HPC-8000", "HPC-8000-65T", "HPC-8000H", "HPC-8000H-65TM" (manufactured by DIC); "HP-B-8151-62T", "EXB-8100L-65T", "EXB-8150-60T", "EXB-8150-62T", "EXB-9416-70BK" as active ester compounds containing a naphthalene structure, "HPC-8150-60T", "HPC-8150-62T", "EXB-8" (manufactured by DIC Corporation); "EXB9401" (manufactured by DIC Corporation) as a phosphorus-containing active ester compound, which is an acetylated product of phenol novolac "DC808" (manufactured by Mitsubishi Chemical Corporation) as an active ester compound, "YLH1026", "YLH1030" and "YLH1048" (manufactured by Mitsubishi Chemical Corporation) as active ester compounds that are benzoyl compounds of phenol novolak, styryl groups and naphthalene structures. Examples of active ester compounds include "PC1300-02-65MA" (manufactured by Air Water).

As the phenolic curing agent, a phenolic curing agent having a novolac structure is preferable from the viewpoint of heat resistance and water resistance. From the viewpoint of adhesion to adherends, a nitrogen-containing phenolic curing agent is preferred, and a triazine skeleton-containing phenolic curing agent is more preferred. Among them, a triazine skeleton-containing phenol novolak resin is preferable from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion. Specific examples of the phenol-based curing agent include, for example, Meiwa Chemical Co., Ltd. "MEH-7700", "MEH-7810", "MEH-7851", Nippon Kayaku Co., Ltd. "NHN", "CBN", " GPH", "SN-170", "SN-180", "SN-190", "SN-475", "SN-485", "SN-495", "SN- 375", "SN-395", DIC's "LA-7052", "LA-7054", "LA-3018", "LA-3018-50P", "LA-1356", "TD2090", " TD-2090-60M" and the like.

Examples of carbodiimide-based curing agents include curing agents having one or more, preferably two or more carbodiimide structures in one molecule. biscarbodiimides such as aromatic biscarbodiimides such as phenylene-bis(xylylcarbodiimide); polyhexamethylenecarbodiimide, polytrimethylhexamethylenecarbodiimide, polycyclohexylenecarbodiimide, poly(methylene biscyclohexylenecarbodiimide), poly(isophoronecarbodiimide) and other aliphatic polycarbodiimides; poly(phenylenecarbodiimide), poly(naphthylenecarbodiimide), poly(tylenecarbodiimide), poly(methyldiisopropylphenylenecarbodiimide), poly(triethylphenylene carbodiimide), poly(diethylphenylenecarbodiimide), poly(triisopropylphenylenecarbodiimide), poly(diisopropylphenylenecarbodiimide), poly(xylylenecarbodiimide), poly(tetramethylxylylenecarbodiimide), poly(methylenediphenylenecarbodiimide), poly Examples include polycarbodiimides such as aromatic polycarbodiimides such as [methylenebis(methylphenylene)carbodiimide].

Examples of commercially available carbodiimide curing agents include "Carbodilite V-02B", "Carbodilite V-03", "Carbodilite V-04K", "Carbodilite V-07" and "Carbodilite V-09" manufactured by Nisshinbo Chemical Co., Ltd. "Stabaxol P", "Stabaxol P400", and "Hykasil 510" manufactured by Rhein Chemie.

Acid anhydride curing agents include curing agents having one or more acid anhydride groups in one molecule, and curing agents having two or more acid anhydride groups in one molecule are preferred. Specific examples of acid anhydride curing agents include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, and hydrogenated methylnadic acid. anhydride, trialkyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trianhydride mellitic acid, pyromellitic anhydride, benzophenonetetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'- Diphenylsulfonetetracarboxylic 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), polymer-type acid anhydrides such as styrene/maleic acid resin obtained by copolymerizing styrene and maleic acid. Commercially available acid anhydride-based curing agents include "HNA-100", "MH-700", "MTA-15", "DDSA" and "OSA" manufactured by Shin Nippon Rika Co., Ltd., and " YH-306", "YH-307", Hitachi Chemical "HN-2200", "HN-5500", Clay Valley "EF-30", "EF-40" "EF-60", "EF -80” and the like.

Amine-based curing agents include curing agents having one or more, preferably two or more amino groups in one molecule. Examples include aliphatic amines, polyether amines, alicyclic amines, Aromatic amines and the like can be mentioned, and among them, aromatic amines are preferable from the viewpoint of achieving the desired effects of the present invention. Amine-based curing agents are preferably primary amines or secondary amines, more preferably primary amines. Specific examples of amine curing agents include 4,4'-methylenebis(2,6-dimethylaniline), 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, and 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. Commercially available amine-based curing agents may be used, for example, Seika "SEIKACURE-S", Nippon Kayaku "KAYABOND C-200S", "KAYABOND C-100", "KAYAHARD AA". , “Kayahard AB”, “Kayahard AS”, “Epicure W” manufactured by Mitsubishi Chemical Corporation, and the like.

Specific examples of benzoxazine-based curing agents include "JBZ-OP100D" and "ODA-BOZ" manufactured by JFE Chemical Co., Ltd.; "HFB2006M" manufactured by Showa Polymer Co., Ltd.; Examples include "Fa".

Examples of cyanate ester curing agents include bisphenol A dicyanate, polyphenolcyanate (oligo(3-methylene-1,5-phenylenecyanate)), 4,4'-methylenebis(2,6-dimethylphenylcyanate), 4, 4′-ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanatophenylmethane), bis(4-cyanate-3,5- Difunctional cyanate resins such as dimethylphenyl)methane, 1,3-bis(4-cyanatophenyl-1-(methylethylidene))benzene, bis(4-cyanatophenyl)thioether, and bis(4-cyanatophenyl)ether, Polyfunctional cyanate resins derived from phenol novolak, cresol novolak, etc., and prepolymers obtained by partially triazine-forming these cyanate resins. Specific examples of cyanate ester curing agents include "PT30" and "PT60" (both phenol novolac type polyfunctional cyanate ester resins), "BA230" and "BA230S75" (part of bisphenol A dicyanate) manufactured by Lonza Japan Co., Ltd. or a prepolymer that is entirely triazined to form a trimer), and the like.

Examples of thiol curing agents include trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), tris(3-mercaptopropyl)isocyanurate and the like.

(B-2) The reactive group equivalent of the epoxy curing agent is preferably 50 g/eq. ~3000g/eq. , more preferably 100 g/eq. ~1000g/eq. , more preferably 100 g/eq. ~500 g/eq. , particularly preferably 100 g/eq. ~300 g/eq. is. The reactive group equivalent is the mass of (B-2) epoxy curing agent per equivalent of reactive group.

(B-2) The content (% by mass) of the epoxy curing agent is not particularly limited, but is preferably 50% by mass or less, more preferably 50% by mass or less, when the non-volatile component in the resin composition is 100% by mass. is 30% by mass or less, more preferably 20% by mass or less, and particularly preferably 10% by mass or less. Moreover, the lower limit may be, for example, 0% by mass or more, 0.05% by mass or more, or 0.1% by mass or more.

<(C) Curing accelerator>
When the resin composition of the present invention contains (B-1) epoxy resin as (B) thermosetting resin, it may contain (C) curing accelerator as an optional component. (C) Curing accelerator has a function of accelerating curing of (B-1) epoxy resin.

(C) Curing accelerators include, for example, imidazole-based curing accelerators, phosphorus-based curing accelerators, urea-based curing accelerators, guanidine-based curing accelerators, metal-based curing accelerators, and amine-based curing accelerators. . In one embodiment, (C) the curing accelerator preferably contains a curing accelerator selected from imidazole-based curing accelerators and phosphorus-based curing accelerators. (C) A hardening accelerator may be used individually by 1 type, and may be used in combination of 2 or more types.

Examples of imidazole curing accelerators include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 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'-undecyl imidazolyl-(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 isocyanurate, 2-phenylimidazole isocyanurate, 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 other imidazole compounds, and adducts of imidazole compounds and epoxy resins.

As the imidazole-based curing accelerator, a commercially available product may be used, for example, "1B2PZ", "2MZA-PW", "2PHZ-PW" manufactured by Shikoku Kasei Co., Ltd., "P200-H50" manufactured by Mitsubishi Chemical Corporation. etc.

Phosphorus curing accelerators include, for example, tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium acetate, tetrabutylphosphonium decanoate, tetrabutylphosphonium laurate, bis(tetrabutylphosphonium) pyromellitate, tetrabutylphosphonium hydro Aliphatic phosphonium salts such as genhexahydrophthalate, tetrabutylphosphonium 2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-methylphenolate, di-tert-butylmethylphosphonium tetraphenylborate; methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, propyltriphenylphosphonium bromide, butyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, tetraphenylphosphonium bromide, p-tolyltriphenylphosphonium tetra-p-tolylborate, tetraphenyl phosphonium tetraphenylborate, tetraphenylphosphonium tetra-p-tolylborate, triphenylethylphosphonium tetraphenylborate, tris(3-methylphenyl)ethylphosphonium tetraphenylborate, tris(2-methoxyphenyl)ethylphosphonium tetraphenylborate, (4 -methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, aromatic phosphonium salts such as butyltriphenylphosphonium thiocyanate; aromatic phosphine/borane complexes such as triphenylphosphine/triphenylborane; triphenylphosphine/p-benzoquinone Aromatic phosphine/quinone addition reaction products such as addition reaction products; 2-butenyl)phosphine, aliphatic phosphines such as tricyclohexylphosphine; - tolylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine Sphines, 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) Aromatic phosphines such as butane, 1,2-bis(diphenylphosphino)acetylene, 2,2'-bis(diphenylphosphino)diphenyl ether, and the like can be mentioned.

Urea-based curing accelerators include, for example, 1,1-dimethylurea; 1,1,3-trimethylurea, 3-ethyl-1,1-dimethylurea, 3-cyclohexyl-1,1-dimethylurea, 3- Aliphatic dimethylurea such as cyclooctyl-1,1-dimethylurea; 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) Aromatic dimethylurea such as bis(N',N'-dimethylurea), N,N-(4-methyl-1,3-phenylene)bis(N',N'-dimethylurea) [toluenebisdimethylurea] etc.

Guanidine curing accelerators include, for example, 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 and the like.

Metal-based curing accelerators include, for example, organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organometallic complexes include organocobalt complexes such as cobalt (II) acetylacetonate and cobalt (III) acetylacetonate, organocopper complexes such as copper (II) acetylacetonate, and zinc (II) acetylacetonate. organic zinc complexes such as iron (III) acetylacetonate; organic nickel complexes such as nickel (II) acetylacetonate; organic manganese complexes such as manganese (II) acetylacetonate; Examples of organic metal salts include zinc octoate, tin octoate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

Examples of amine 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 and the like.

As the amine-based curing accelerator, a commercially available product may be used, such as "MY-25" manufactured by Ajinomoto Fine-Techno Co., Ltd., and the like.

(C) The content (% by mass) of the curing accelerator is not particularly limited, but when the non-volatile component in the resin composition is 100% by mass, it is preferably 10% by mass or less, more preferably 5% by mass. % by mass or less, more preferably 3% by mass or less, particularly preferably 2% by mass or less. Moreover, the lower limit may be, for example, 0% by mass or more, 0.001% by mass or more, or 0.01% by mass or more.

<(D) Thermoplastic resin>
The resin composition of the present invention may contain (D) a thermoplastic resin as an optional component. The (D) thermoplastic resin described here is a component that does not correspond to the (B) thermosetting resin described above.

(D) Thermoplastic resins include, for example, phenoxy resins, polyvinyl acetal resins, polyolefin resins, polybutadiene resins, polyimide resins, polyamideimide resins, polyetherimide resins, polysulfone resins, polyethersulfone resins, polyphenylene ether resins, and polycarbonate resins. , polyether ether ketone resin, polyester resin, and the like. Among them, phenoxy resin is preferable. Further, the thermoplastic resin may be used singly or in combination of two or more.

Examples of phenoxy resins include bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenolacetophenone skeleton, novolac skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantane skeleton, and terpene. Examples include phenoxy resins having one or more skeletons selected from the group consisting of skeletons and trimethylcyclohexane skeletons. 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 Mitsubishi Chemical's "1256" and "4250" (both bisphenol A skeleton-containing phenoxy resins); Mitsubishi Chemical's "YX8100" (bisphenol S skeleton-containing phenoxy resin); Mitsubishi Chemical "YX6954" (bisphenolacetophenone skeleton-containing phenoxy resin) manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.; "FX280" and "FX293" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.; "YL7769BH30", "YL6794", "YL7213", "YL7290", "YL7482" and "YL7891BH30";

Examples of polyvinyl acetal resins include polyvinyl formal resins and polyvinyl butyral resins, and polyvinyl butyral resins are preferred. Specific examples of polyvinyl acetal resins include Denka Butyral 4000-2, Denka Butyral 5000-A, Denka Butyral 6000-C, and Denka Butyral 6000-EP manufactured by Sekisui Chemical Co., Ltd. S-LEC BH series, BX series (eg BX-5Z), KS series (eg KS-1), BL series, BM series;

Examples of polyolefin resins include ethylene-based copolymers such as low-density polyethylene, ultra-low-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-methyl acrylate copolymer. Resin: polyolefin polymers such as polypropylene and ethylene-propylene block copolymers.

Specific examples of the polyimide resin include "Ricacoat SN20" and "Ricacoat PN20" manufactured by Shin Nippon Rika.

Specific examples of polyamide-imide resins include "VYLOMAX HR11NN" and "VYLOMAX HR16NN" manufactured by Toyobo Co., Ltd. Specific examples of polyamideimide resins include modified polyamideimides such as "KS9100" and "KS9300" (polysiloxane skeleton-containing polyamideimides) manufactured by Hitachi Chemical Co., Ltd.

Specific examples of the polyethersulfone resin include "PES5003P" manufactured by Sumitomo Chemical Co., Ltd., and the like.

Specific examples of the polysulfone resin include polysulfone "P1700" and "P3500" manufactured by Solvay Advanced Polymers.

Examples of polyester resins include polyethylene terephthalate resin, polyethylene naphthalate resin, polybutylene terephthalate resin, polybutylene naphthalate resin, polytrimethylene terephthalate resin, polytrimethylene naphthalate resin, polycyclohexanedimethyl terephthalate resin, and the like.

(D) The weight average molecular weight (Mw) of the thermoplastic resin is preferably 8,000 or more, more preferably 10,000 or more, and particularly preferably 20,000 or more, from the viewpoint of significantly obtaining the effects of the present invention. , preferably 70,000 or less, more preferably 60,000 or less, and particularly preferably 50,000 or less.

(D) The content (% by mass) of the thermoplastic resin is not particularly limited, but when the non-volatile component in the resin composition is 100% by mass, it is preferably 50% by mass or less, more preferably 20% by mass. % by mass or less, more preferably 10% by mass or less, particularly preferably 6% by mass or less. Moreover, the lower limit may be, for example, 0% by mass or more, 0.01% by mass or more, 0.1% by mass or more, or 1% by mass or more.

<(E) Dispersant>
The resin composition of the present invention may contain (E) a dispersant as an optional component.

(E) Dispersants include, for example, phosphate-based dispersants such as polyoxyethylene alkyl ether phosphoric acid; polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkylphenyls polyoxyalkylene-based dispersants such as ethers, polyoxyethylene alkylamines, and polyoxyethylene alkylamides; acetylene-based dispersants such as acetylene glycol; polyether-modified polydimethylsiloxane, polyether-modified siloxane, polyester-modified polydimethylsiloxane, etc. Silicone dispersants; Anionic dispersants such as sodium polyacrylate, sodium dodecylbenzene sulfonate, sodium laurate, polyoxyethylene alkyl ether sulfate ammonium, carboxymethylcellulose sodium salt; amino group-containing polyacrylate resins, amino groups Cationic dispersants such as contained polystyrene resins and the like can be mentioned. (E) Dispersants may be used singly or in combination of two or more.

Commercially available phosphate ester dispersants include "RS-410", "RS-610", and "RS-710" of the "Phosphanol" series manufactured by Toho Chemical Industry Co., Ltd.

Commercially available polyoxyalkylene dispersants include NOF's "MALIALIM" series "AKM-0531", "AFB-1521", "SC-0505K", "SC-1015F" and "SC-0708A". , and “HKM-50A”.

Commercially available acetylene-based dispersants are available from Air Products and Chemicals Inc.; "Surfinol" series "82", "104", "440", "465" and "485", and "Olefin Y".

Examples of commercially available silicone-based dispersants include "BYK347" and "BYK348" manufactured by BYK-Chemie.

Commercially available anionic dispersants include "PN-411" and "PA-111" manufactured by Ajinomoto Fine-Techno Co., Ltd.; "A-550" and "PS-1900" manufactured by Lion Corporation.

Commercially available cationic dispersants include "161", "162", "164", "182", "2000" and "2001" manufactured by BYK Chemie; "PB-821" and "PB" manufactured by Ajinomoto Fine-Techno Co. -822", "PB-824"; "V-216", "V-220" manufactured by ISP Japan;

(E) The content (% by mass) of the dispersant is not particularly limited, but when the non-volatile component in the resin composition is 100% by mass, it is preferably 20% by mass or less, more preferably 15% by mass. % or less, more preferably 10 mass % or less, particularly preferably 7 mass % or less. Moreover, the lower limit may be, for example, 0% by mass or more, 0.01% by mass or more, 0.1% by mass or more, or 1% by mass or more.

<(F) Other additives>
The resin composition of the present invention may further contain optional additives as non-volatile components. Examples of such additives include maleimide radically polymerizable compounds, vinylphenyl radically polymerizable compounds, (meth)acrylic radically polymerizable compounds, allyl radically polymerizable compounds, polybutadiene radically polymerizable compounds, and the like. Radical polymerizable compounds; radical polymerization initiators such as peroxide radical polymerization initiators and azo radical polymerization initiators; organic fillers such as rubber particles; organic metal compounds such as organic copper compounds and organic zinc compounds; Polymerization inhibitors such as catechol, pyrogallol, and phenothiazine; leveling agents such as silicone leveling agents and acrylic polymer leveling agents; thickeners such as bentone and montmorillonite; Antifoaming agents such as foaming agents and vinyl resin antifoaming agents; UV absorbers such as benzotriazole UV absorbers; Adhesion improvers such as urea silane; adhesion-imparting agents such as triazine-based adhesion-imparting agents; antioxidants such as hindered phenol-based antioxidants; surfactants such as fluorine-based surfactants and silicone-based surfactants; flame retardants such as acid ester compounds, phosphazene compounds, phosphinic acid compounds, red phosphorus), nitrogen flame retardants (e.g. melamine sulfate), halogen flame retardants, inorganic flame retardants (e.g. antimony trioxide); borate stabilizers, Stabilizers such as titanate-based stabilizers, aluminate-based stabilizers, zirconate-based stabilizers, isocyanate-based stabilizers, carboxylic acid-based stabilizers, and carboxylic acid anhydride-based stabilizers are included. (F) Other additives may be used singly or in combination of two or more at any ratio. (F) The content of other additives can be appropriately set by those skilled in the art.

<(G) Organic solvent>
The resin composition of the present invention may further contain an arbitrary organic solvent as a volatile component in addition to the non-volatile component described above. For example, when producing a film from a resin composition, it is possible to form a resin composition layer by forming a varnish with an organic solvent, applying the varnish of the resin composition onto a support, and drying the varnish. , the resin composition layer may contain a solvent as a residual solvent. As the organic solvent (G), as long as it is capable of dissolving at least part of the non-volatile components, any known organic solvent can be appropriately used, and the type thereof is not particularly limited. Examples of (G) organic solvents include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, γ- ester solvents such as 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, methyl methoxypropionate; methyl lactate, ethyl lactate, 2-hydroxyisobutyric acid ester alcohol solvents such as methyl; ether alcohol solvents such as 2-methoxypropanol, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, diethylene glycol monobutyl ether (butyl carbitol); N,N-dimethylformamide, Amide solvents such as N,N-dimethylacetamide and N-methyl-2-pyrrolidone; sulfoxide solvents such as dimethylsulfoxide; nitrile solvents such as acetonitrile and propionitrile; hexane, cyclopentane, cyclohexane, methylcyclohexane and the like Aliphatic hydrocarbon solvents; aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, trimethylbenzene, and the like can be mentioned. (G) The organic solvent may be used singly or in combination of two or more at any ratio. (G) The organic solvent may be used singly or in combination of two or more at any ratio.

(G) The content of the organic solvent is used for printing, hole-filling, etc., so when making a paste-like resin composition, the lower the content of the organic solvent, the better. When 100% by mass, it is preferably 1% by mass or less, more preferably 0.8% by mass or less, even more preferably 0.5% by mass or less, and particularly preferably 0.1% by mass or less. The lower limit is not particularly limited, and can be, for example, 0.001% by mass, but ideally it is 0% by mass. When the varnish for film preparation is a resin composition, the content of the organic solvent is preferably 20% by mass or less, more preferably 10% by mass or less, when all components in the resin composition are 100% by mass. More preferably 8% by mass or less, particularly preferably 6% by mass or less. The lower limit is not particularly limited, and may be, for example, 0.001% by mass or more. The residual solvent content in the film is preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 2% by mass or less, and particularly preferably 1% by mass or less. The lower limit is not particularly limited, and may be, for example, 0.001% by mass or more. (G) If the content of the organic solvent is reduced, the generation of voids due to volatilization of the organic solvent can be suppressed, and the handleability and workability can be improved.

<Characteristics of resin composition>
The resin composition of the present invention comprises (A) magnetic powder and (B) a thermosetting resin, wherein (A) magnetic powder comprises (A-1) flat magnetic powder and (A- 2) It contains spherical magnetic powder, and (A-1) the flat magnetic powder has an average minor axis length of 1 μm or more. By using such a resin composition, it is possible to obtain a magnetic material that can be easily formed into a paste or a film and has excellent relative magnetic permeability.

A cured product of the resin composition of the present invention can have an excellent relative magnetic permeability (μ′). Therefore, in one embodiment, the relative magnetic permeability (μ′) of the cured product of the resin composition when measured at a measurement frequency of 10 MHz and 23° C. as in Test Example 2 below is preferably 4 or more, 6 or more, or more. It can be preferably 8 or more, 10 or more, 11 or more, more preferably 12 or more, 13 or more, and particularly preferably 14 or more, 15 or more.

The resin composition of the present invention may have moderate viscosity in one embodiment. Therefore, in one embodiment, when a paste for filling holes or the like is used, the viscosity at 25 ° C. (±2 ° C.) measured using an E-type viscometer as in Test Example 3 below is preferably 0.05 Pa s or more, more preferably 0.1 Pa s or more, more preferably 0.5 Pa s or more, particularly preferably 1 Pa s or more, and the upper limit is preferably 1500 Pa s or less, more preferably 1200 Pa s. Below, it is more preferably 1000 Pa·s or less, and particularly preferably 800 Pa·s or less.

When used as a paste (varnish) for film preparation, the viscosity at 25° C. (±2° C.) measured using an E-type viscometer as in Test Example 3 below is preferably 0.05 Pa s or more, It is more preferably 0.1 Pa·s or more, still more preferably 0.5 Pa·s or more, and particularly preferably 1 Pa·s or more, and the upper limit is preferably 200 Pa·s or less, more preferably 100 Pa·s or less, and still more preferably. is 80 Pa·s or less, particularly preferably 50 Pa·s or less.

<Method for producing resin composition>
The resin composition of the present invention can be, for example, placed in any preparation container (A) magnetic powder, (B) thermosetting resin, optionally (C) curing accelerator, and optionally (D) thermoplastic A resin, optionally (E) a dispersant, optionally (F) other additives, and optionally (G) an organic solvent are added in any order and/or partly or wholly at the same time. It can be manufactured by mixing. Also, during the process of adding and mixing each component, the temperature can be set appropriately, and heating and/or cooling may be performed temporarily or over time. Moreover, you may stir or shake in the process of adding and mixing each component. In addition, during or after the addition and mixing, the resin composition may be stirred or shaken, for example, using a stirring device or shaking device such as a mixer to uniformly disperse. Moreover, simultaneously with stirring or shaking, defoaming may be performed under low pressure conditions such as vacuum.

<Form of resin composition>
In forming the magnetic cured product of the substrate, the resin composition may be used in the form of a paste-like resin composition at room temperature (25° C. (±2° C.)), and a resin sheet containing a layer of the resin composition may be used. may be used in the form of The pasty resin composition is, for example, a viscosity of 0.05 Pa s to 1500 Pa s at normal temperature (25 ° C. (±2 ° C.)) measured using an E-type viscometer as in Test Example 3 below. It can be a resin composition within the range.

In one embodiment, the resin composition may be a paste resin composition using an organic solvent, or a paste containing no organic solvent by using a liquid thermosetting resin such as a liquid epoxy resin. It is good also as a resin composition of shape.

In one embodiment, the resin composition can be suitably used as a resin composition for filling through holes. Moreover, in one embodiment, the resin composition can be suitably used as a resin composition for forming an inductor-based element for manufacturing an inductor element.

<Resin sheet>
The resin sheet includes a support and a resin composition layer formed of the resin composition of the present invention provided on the support.

The thickness of the resin composition layer is preferably 250 µm or less, more preferably 200 µm or less, from the viewpoint of thinning. Although the lower limit of the thickness of the resin composition layer is not particularly limited, it can be usually 5 μm or more, 10 μm or more, or the like.

Examples of the support include a film made of a plastic material, a metal foil, and a release paper, and a film made of a plastic material and a metal foil are preferable.

When a film made of a plastic material is used as the support, examples of the plastic material include polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate (hereinafter sometimes abbreviated as "PEN"). ), polyesters such as polycarbonate (hereinafter sometimes abbreviated as "PC"), acrylic polymers such as polymethyl methacrylate (PMMA), cyclic polyolefins, triacetyl cellulose (TAC), polyether sulfide (PES), poly Ether ketone, polyimide and the like can be mentioned. Among them, polyethylene terephthalate and polyethylene naphthalate are preferable, and inexpensive polyethylene terephthalate is particularly preferable.

When a metal foil is used as the support, examples of the metal foil include copper foil and aluminum foil, with copper foil being preferred. As the copper foil, a foil made of a single metal of copper may be used, and 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. may be used.

The support may be subjected to matte treatment or corona treatment on the surface to be bonded to the resin composition layer.

Further, as the support, a support with a release layer having a release layer on the surface to be bonded to the resin composition layer may be used. The release agent used in the release layer of the support with a release layer is selected from the group consisting of, for example, alkyd release agents, polyolefin release agents, urethane release agents, and silicone release agents. and one or more mold release agents. The support with a release layer may be a commercially available product, for example, a PET film having a release layer mainly composed of a silicone-based release agent or an alkyd resin-based release agent. PET501010", "SK-1", "AL-5", "AL-7"; "Lumirror T60" manufactured by Toray Industries, Inc.; "Purex" manufactured by Teijin; and "Unipeel" manufactured by Unitika. .

The thickness of the support is not particularly limited, but is preferably in the range of 5 μm to 75 μm, more preferably in the range of 10 μm to 60 μm. When a release layer-attached support is used, the thickness of the release layer-attached support as a whole is preferably within the above range.

In the resin sheet, a protective film conforming to the support can be further laminated on the surface of the resin composition layer that is not bonded to the support (that is, the surface opposite to the support). Although the thickness of the protective film is not particularly limited, it is, for example, 1 μm to 40 μm. By laminating the protective film, the surface of the resin composition layer can be prevented from being dusted or scratched. The resin sheet can be wound into a roll and stored. When the resin sheet has a protective film, it can be used by peeling off the protective film.

A resin sheet can be produced, for example, by coating a resin composition on a support using a die coater or the like to form a resin composition layer. If necessary, the resin composition may be mixed with an organic solvent and then applied onto the support. When an organic solvent is used, drying may be performed after application, if necessary.

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

The resin sheet can be wound into a roll and stored. When the resin sheet has a protective film, it can be used by peeling off the protective film.

<Circuit board and its manufacturing method>
The circuit board of the present invention contains a cured product of the resin composition. The circuit board of the first embodiment includes a substrate having through holes and a cured resin composition of the present invention filling the through holes. Moreover, the circuit board of the second embodiment includes a cured product layer formed from a cured product of the resin composition layer of the resin sheet. A first embodiment and a second embodiment of a method for manufacturing a circuit board will be described below. However, the method for manufacturing a circuit board according to the present invention is not limited to the first and second embodiments illustrated below.

<First embodiment>
The circuit board of the first embodiment is manufactured, for example, by a manufacturing method including the following steps (1) to (5). In the first embodiment, it is preferable to form the cured product using the resin composition, and it is more preferable to form the cured product using a pasty resin composition.
(1) a step of filling a through-hole of a substrate having a through-hole with a resin composition;
(2) a step of thermally curing the resin composition to obtain a cured product;
(3) polishing the surface of the cured product or resin composition;
(4) a step of roughening the cured product; and (5) a step of forming a conductor layer on the roughened surface of the cured product.
In the method for manufacturing a circuit board of the present invention, steps (1) to (5) may be performed in order, or step (2) may be performed after step (3).

<Step (1)>
In carrying out the step (1), a step of preparing a resin composition may be included. The resin composition is as described above.

Further, in performing the step (1), as shown in FIG. 1, a supporting substrate 11, first metal layers 12 made of metal such as copper foil provided on both surfaces of the supporting substrate 11, and first A step of preparing a core substrate 10 with two metal layers 13 may be included. Examples of materials for the support substrate 11 include insulating substrates such as glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates. Examples of materials for the first and second metal layers include carrier-attached copper foils and materials for the conductor layers described later.

Moreover, as an example is shown in FIG. 2, a step of forming through holes 14 in the core substrate 10 may be included. The through holes 14 can be formed by drilling, laser irradiation, plasma irradiation, or the like, for example. Specifically, the through hole 14 can be formed by forming a through hole in the core substrate 10 using a drill or the like.

Formation of the through holes 14 can be carried out using commercially available drilling equipment. Examples of commercially available drilling devices include "ND-1S211" manufactured by Hitachi Via Mechanics.

After the through-holes 14 are formed in the core substrate 10, the core substrate 10 is roughened as shown in FIG. A step of forming a plating layer 20 on the surface of 13 may be included.

As the roughening treatment, either dry or wet roughening treatment may be performed. Examples of dry roughening treatment include plasma treatment and the like. Moreover, examples of wet roughening treatment include a method in which swelling treatment with a swelling liquid, roughening treatment with an oxidizing agent, and neutralization treatment with a neutralizing liquid are performed in this order.

The plating layer 20 is formed by the plating method, and the procedure for forming the plating layer 20 by the plating method is the same as the formation of the conductor layer in step (5) described later.

After the core substrate 10 is prepared, the through holes 14 are filled with the resin composition 30a as shown in FIG. Filling can be done, for example, by a printing method. The printing method includes, for example, a method of printing the resin composition 30a onto the through holes 14 via a squeegee, a method of printing the resin composition 30a via a cartridge, a method of printing the resin composition 30a by mask printing, A roll coating method, an inkjet method, and the like can be mentioned.

<Step (2)>
In step (2), after filling the through holes 14 with the resin composition 30a, the resin composition 30a is thermally cured to form a cured product 30 inside the through holes 14, as an example is shown in FIG. The thermosetting conditions for the resin composition 30a vary depending on the composition and type of the resin composition 30a. It is 245° C. or lower, more preferably 220° C. or lower, and still more preferably 200° C. or lower. The curing time of the resin composition 30a 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. is.

The degree of cure of the cured product 30 in step (2) is preferably 80% or higher, more preferably 85% or higher, and even more preferably 90% or higher. The degree of cure can be measured, for example, using a differential scanning calorimeter.

Before thermally curing the resin composition 30a, the resin composition 30a may be subjected to a preheating treatment in which the resin composition 30a is heated at a temperature lower than the curing temperature. For example, prior to thermosetting the resin composition 30a, the resin composition 30a is usually heated at a temperature of 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). may be preheated for usually 5 minutes or more (preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes).

<Step (3)>
In step (3), as an example is shown in FIG. 6, excess hardened material 30 protruding from or adhering to the core substrate 10 is removed by polishing and planarized. As a polishing method, a method capable of polishing the excessive cured product 30 protruding from or adhering to the core substrate 10 can be used. Examples of such a polishing method include buffing and belt polishing. Commercially available buffing devices include "NT-700IM" manufactured by Ishii Hokumon Co., Ltd., and the like.

The arithmetic mean roughness (Ra) of the polished surface of the cured product 30 (after thermal curing of the cured product layer) is preferably 300 nm or more, more preferably 350 nm or more, from the viewpoint of improving the adhesion between the plating. More preferably, it is 400 nm or more. 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 using, for example, a non-contact surface roughness meter.

When step (3) is performed after step (2), heat treatment may be performed as necessary after step (2) and before step (3) for the purpose of further increasing the degree of hardening of the cured product 30 . The temperature in the heat treatment may be carried out according to the curing temperature described above, preferably 120° C. or higher, more preferably 130° C. or higher, still more preferably 150° C. or higher, preferably 245° C. or lower, more preferably 220° C. or lower. , and more preferably 200° C. or less. The heat treatment time is preferably 5 minutes or longer, more preferably 10 minutes or longer, still more preferably 15 minutes or longer, and preferably 90 minutes or shorter, more preferably 70 minutes or shorter, still more preferably 60 minutes or shorter.

Moreover, when performing the step (3) before the step (2), a preheating treatment of heating at a temperature lower than the curing temperature of the resin composition may be performed before the step (3). The temperature in the preliminary heat treatment is preferably 100° C. or higher, more preferably 110° C. or higher, still more preferably 120° C. or higher, and preferably 245° C. or lower, more preferably 220° C. or lower, and still more preferably 200° C. or lower. be. The heat treatment time is preferably 5 minutes or longer, more preferably 10 minutes or longer, still more preferably 15 minutes or longer, and preferably 90 minutes or shorter, more preferably 70 minutes or shorter, still more preferably 60 minutes or shorter.

<Step (4)>
In step (4), the surface polished in step (3) is roughened (desmeared). The procedure and conditions of the roughening step are not particularly limited, and known procedures and conditions that are commonly used in the production of multilayer printed wiring boards can be employed. As the roughening step, for example, the cured product 30 can be roughened by performing swelling treatment with a swelling liquid, roughening treatment with an oxidizing agent, and neutralization treatment with a neutralizing liquid in this order.

The swelling liquid that can be used in the roughening step is not particularly limited, but includes alkaline solutions, surfactant solutions, etc., preferably alkaline solutions. A sodium hydroxide solution and a potassium hydroxide solution are more preferable as the alkaline solution that is the swelling liquid. Examples of commercially available swelling liquids include "Swelling Dip Securigans P" and "Swelling Dip Securigans SBU" manufactured by Atotech Japan.

The swelling treatment with the swelling liquid is not particularly limited, but can be performed, for example, by immersing the core substrate 20 provided with 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 constituting 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.

The oxidizing agent that can be used for the roughening treatment with an oxidizing agent is not particularly limited, but examples thereof include 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 performed by immersing the cured product 30 in an oxidizing agent solution heated to 60° C. to 80° C. for 10 to 30 minutes. Further, the permanganate concentration in the alkaline permanganate solution is preferably 5% by mass to 10% by mass. Examples of commercially available oxidizing agents include alkaline permanganate solutions such as "Concentrate Compact P" and "Dosing Solution Security P" manufactured by Atotech Japan.

As a neutralizing solution that can be used for the neutralization treatment, an acidic aqueous solution is preferable, and commercially available products include, for example, "Reduction Solution Security P" manufactured by Atotech Japan. The neutralization treatment with the neutralizing solution can be carried out by immersing the treated surface roughened with the oxidant solution in the neutralizing solution at 30° C. to 80° C. for 5 to 30 minutes. From the viewpoint of workability, etc., a method of immersing the cured product 30 roughened with an oxidizing agent solution in a neutralizing solution at 40° C. to 70° C. for 5 to 20 minutes is preferable.

The arithmetic mean roughness (Ra) of the cured product 30 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 the plating. . 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.

<Step (5)>
In step (5), as an example is shown in FIG. 7, a conductor layer 40 is formed on the polished surface of the cured product 30 and on the core substrate. Further, after the conductor layer 40 is formed, as shown in FIG. 8, the conductor layer 40, the first metal layer 12, the second metal layer 13, and the plating layer 20 are partially removed by etching or the like. A pattern conductor layer 41 may be formed. Although the conductor layer 40 is formed on both surfaces of the core substrate 10 in FIG. 7 , the conductor layer 40 may be formed on only one surface of the core substrate 10 .

The method of forming the conductor layer 40 includes, for example, a plating method, a sputtering method, a vapor deposition method, etc. Among them, the plating method is preferable. In a preferred embodiment, the surface of the cured product 30 (and the plating layer 20) is plated by an appropriate method such as a semi-additive method or a full-additive method to form a patterned conductor layer 41 having a desired wiring pattern. Materials for the conductor layer 40 include, for example, single metals such as gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium; gold, platinum, palladium, Alloys of two or more metals selected from the group of silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin and indium are included. Among them, chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or nickel-chromium alloys, copper-nickel alloys, and copper-titanium alloys can be used from the viewpoint of versatility, cost, ease of patterning, and the like. Chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or nickel-chromium alloys are preferably used, and copper is even more preferred.

Here, an example of an embodiment in which the pattern conductor layer 41 is formed on the polished surface of the cured product 30 will be described in detail. A plating seed layer is formed by electroless plating on the polished surface of the cured product 30 . Next, an electroplating layer is formed on the formed plating seed layer by electroplating, and if necessary, an unnecessary plating seed layer is removed by a treatment such as etching, and a conductor layer 40 having a desired wiring pattern is formed. can be formed. After the conductor layer 40 is formed, annealing treatment may be performed as necessary for the purpose of improving the peel strength of the conductor layer 40 . Annealing treatment can be performed, for example, by heating the circuit board at 150 to 200° C. for 20 to 90 minutes.

The thickness of the pattern conductor layer is preferably 70 μm or less, more preferably 60 μm or less, even more preferably 50 μm or less, even more preferably 40 μm or less, and particularly preferably 30 μm or less and 20 μm or less, from the viewpoint of thinning. , 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.

<Second embodiment>
The circuit board of the second embodiment includes a cured product layer formed from a cured resin composition. In the second embodiment, it is preferable to form the cured material layer using a resin sheet. A second embodiment of the method for manufacturing a product substrate will be described below. Descriptions of portions that overlap with the first embodiment will be omitted as appropriate.

The circuit board of the second embodiment is manufactured, for example, by a manufacturing method including the following steps (A) to (D).
(A) a step of laminating the resin sheet on the inner layer substrate so that the resin composition layer is bonded to the inner layer substrate to form a cured product layer;
(B) a step of perforating the cured material layer;
(C) a step of roughening the surface of the cured layer; and (D) a step of forming a conductor layer on the polished surface of the cured layer.

The above steps (A) to (D) for manufacturing the circuit board will be described in detail below.

<Step (A)>
Step (A) is a step of laminating the resin sheet on the inner layer substrate so that the resin composition layer is bonded to the inner layer substrate to form a cured product layer. As one embodiment of step (A), the resin sheet is laminated on the inner layer substrate so that the resin composition layer is bonded to the inner layer substrate, and the resin composition layer is thermally cured to form a cured material layer.

In step (A), as shown in an example in FIG. 9, a resin sheet 310 including a support 330 and a resin composition layer 320a provided on the support 330 is placed on the inner layer substrate. 200 is laminated on the inner layer substrate 200 .

The inner layer substrate 200 is an insulating substrate. Examples of materials for the inner layer substrate 200 include insulating substrates such as glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates. The inner layer board 200 may be an inner layer circuit board in which wiring and the like are formed within its thickness.

As an example is shown in FIG. 9, the inner substrate 200 has a first conductor layer 420 provided on the first main surface 200a and an external terminal 240 provided on the second main surface 200b. The first conductor layer 420 may include multiple wires. In the illustrated example, only the wiring forming the coiled conductive structure 400 of the inductor element is shown. The external terminal 240 is a terminal for electrically connecting to an external device or the like (not shown). The external terminals 240 can be configured as part of a conductor layer provided on the second main surface 200b.

The conductor material that can form the first conductor layer 420 and the external terminal 240 is the same as the material of the conductor layer described in the "<Step (5)>" section of the first embodiment.

The first conductor layer 420 and the external terminal 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 kinds of metals or alloys are laminated. Also, the thicknesses of the first conductor layer 420 and the external terminals 240 are the same as those of the second conductor layer 440 described later.

Although the line (L)/space (S) ratio of the first conductor layer 420 and the external terminal 240 is not particularly limited, it is usually 900/900 μm from the viewpoint of obtaining a cured product layer with excellent smoothness by reducing the unevenness of the surface. Below, it is preferably 700/700 μm or less, more preferably 500/500 μm or less, even more preferably 300/300 μm or less, and even more preferably 200/200 μm or less. Although the lower limit of the line/space ratio is not particularly limited, it is preferably 1/1 μm or more from the viewpoint of better embedding of the resin composition layer into the space.

Inner layer substrate 200 may have a plurality of through holes 220 penetrating through inner layer substrate 200 from first main surface 200a to second main surface 200b. Through-hole 220 is provided with in-through-hole wiring 220a. Through-hole wiring 220 a electrically connects first conductor layer 420 and external terminal 240 .

The bonding between the resin composition layer 320a and the inner substrate 200 can be performed, for example, by thermocompression bonding the resin sheet 310 to the inner substrate 200 from the support 330 side. A member for thermocompression bonding the resin sheet 310 to the inner layer substrate 200 (hereinafter also referred to as a “thermocompression member”) may be, for example, a heated metal plate (stainless steel (SUS) end plate, etc.) or a metal roll (SUS roll). is mentioned. Instead of pressing the resin sheet 310 by directly contacting the thermocompression member, a sheet made of an elastic material such as heat-resistant rubber is used so that the resin sheet 310 can sufficiently follow the irregularities on the surface of the inner layer substrate 200 . It is preferable to press through

The temperature during thermocompression bonding is preferably in the range of 80° C. to 160° C., more preferably 90° C. to 140° C., still more preferably 100° C. to 120° C., and the pressure during thermocompression bonding is preferably 0.5° C. It is in the range of 098 MPa to 1.77 MPa, more preferably 0.29 MPa to 1.47 MPa, and the time for thermocompression bonding is preferably in the range of 20 seconds to 400 seconds, more preferably 30 seconds to 300 seconds. Bonding of the resin sheet and the inner layer substrate is preferably performed under reduced pressure conditions of 26.7 hPa or less.

Bonding between the resin composition layer 320a of the resin sheet 310 and the inner layer substrate 200 can be performed using a commercially available vacuum laminator. Examples of commercially available vacuum laminators include a vacuum pressurized laminator manufactured by Meiki Seisakusho Co., Ltd., and a vacuum applicator manufactured by Nikko Materials.

After the bonding of the resin sheet 310 and the inner layer substrate 200, the stacked resin sheets 310 are smoothed under normal pressure (atmospheric pressure), for example, by pressing a thermocompression member from the support 330 side. good too. The pressing conditions for the smoothing treatment may be the same as the thermocompression bonding conditions for the lamination described above. Smoothing treatment can be performed with a commercially available laminator. Note that the lamination and the smoothing treatment may be performed continuously using the above-mentioned commercially available vacuum laminator.

After laminating the resin sheet 310 on the inner substrate 200, the resin composition layer 320a is thermally cured to form a cured material layer. As an example is shown in FIG. 10, the resin composition layer 320a bonded to the inner substrate 200 is thermally cured to form the first cured material layer 320. As shown in FIG.

The thermosetting conditions for the resin composition layer 320a vary depending on the composition and type of the resin composition, but the curing temperature is preferably 120° C. or higher, more preferably 130° C. or higher, and still more preferably 150° C. or higher. It is 245° C. or lower, more preferably 220° C. or lower, and still more preferably 200° C. or lower. The curing time of the resin composition layer 320a is preferably 5 minutes or more, more preferably 10 minutes or more, still more preferably 15 minutes or more, preferably 120 minutes or less, more preferably 110 minutes or less, and even more preferably 100 minutes. It is below.

The support 330 may be removed between step (A) after thermal curing and step (B), or may be peeled off after step (B).

The arithmetic mean roughness (Ra) of the cured product layer before 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 the 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 using, for example, a non-contact surface roughness meter.

In the step (A), 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 thermally cured to form a cured material layer.

<Step (B)>
In step (B), as an example is shown in FIG. 11, the first cured material layer 320 is perforated to form via holes 360 . The via hole 360 serves as a path for electrically connecting the first conductor layer 420 and a second conductor layer 440, which will be described later. Formation of the via hole 360 may be performed using, for example, a drill, laser, plasma, or the like, depending on the composition of the resin composition used to form the cured material layer. The dimensions and shape of the holes may be appropriately determined according to the design of the printed wiring board.

<Step (C)>
In step (C), the surface of the cured material layer having via holes is roughened. The roughening treatment in step (C) is as described in the “<step (4)>” section of the first embodiment.

The arithmetic mean roughness (Ra) of the cured product 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 the plating. . The upper limit is preferably 1500 nm or less, more preferably 1200 nm or less, still more preferably 1000 nm or less. The surface roughness (Ra) can be measured using, for example, a non-contact surface roughness meter.

<Step (D)>
In step (D), the second conductor layer 440 is formed on the first cured material layer 320 as shown in FIG. 12 .

The conductor material that can form the second conductor layer 440 is the same as the conductor layer material described in the section “<Step (5)>” of the first embodiment.

The thickness of the second conductor layer 440 is preferably 70 μm or less, more preferably 60 μm or less, even more preferably 50 μm or less, even more preferably 40 μm or less, and particularly preferably 30 μm or less, from the viewpoint of thinning. 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.

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 a semi-additive method or a full-additive method including an electroless plating process, a mask pattern forming process, an electrolytic plating process, and a flash etching process. By forming the second conductor layer 440 using a wet plating method, it is possible to form the second conductor layer 440 including a desired wiring pattern. In this process, via-hole wiring 360a is also formed in the via-hole 360. Next, as shown in FIG.

The first conductor layer 420 and the second conductor layer 440 may be spirally provided, for example, as shown in FIGS. 13 to 15, which will be described later. In one example, one end of the spiral wiring portion of the second conductor layer 440 on the center side is electrically connected to one end of the spiral wiring portion of the first conductor layer 420 on the center side by the in-via-hole wiring 360a. It is 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 42 by the in-via-hole wiring 360a. Therefore, the other end of the spiral wiring portion of the second conductor layer 440 on the outer peripheral side is electrically connected to the external terminal 240 via the via-hole wiring 360a, the land 420a, and the through-hole wiring 220a.

The coil-shaped conductive structure 400 includes a spiral wiring portion that is a portion of the first conductor layer 420, a spiral wiring portion that is a portion of the second conductor layer 440, and a spiral wiring portion of the first conductor layer 420. and the spiral wiring portion of the second conductor layer 440.

After the step (D), a step of forming a cured material layer on the conductor layer may be performed. Specifically, as shown in an example in FIG. 14, the second cured layer 340 is formed on the first cured layer 320 on which the second conductor layer 440 and the in-via-hole wiring 360a are formed. The second cured material layer may be formed by the same steps as those already described.

<Inductor substrate>
The inductor substrate includes the circuit substrate of the present invention. When such an inductor board includes a circuit board obtained by the circuit board manufacturing method of the first embodiment, an inductor pattern formed by a conductor is formed at least partially around the cured product of the resin composition. have. As such an inductor substrate, for example, the one disclosed in Japanese Patent Application Laid-Open No. 2016-197624 can be applied.

Further, when the circuit board includes the circuit board obtained by the circuit board manufacturing method of the second embodiment, the inductor board has a cured material layer and a conductive structure having at least a portion embedded in the cured material layer. and an inductor element extending in the thickness direction of the cured layer and formed by a portion of the cured layer surrounded by the conductive structure. Here, FIG. 13 is a schematic plan view of the inductor substrate containing the inductor element as viewed from one of its thickness directions. FIG. 14 is a schematic diagram showing a cut end surface of the inductor substrate cut at the position indicated by the dashed-dotted line II-II shown in FIG. FIG. 15 is a schematic plan view for explaining the configuration of the first conductor layer of the inductor substrate.

As shown in FIGS. 13 and 14, the circuit board 100 includes a plurality of cured material layers (first cured material layer 320, second cured material layer 340) and a plurality of conductor layers (first conductor layer 420, It is a buildup wiring board having a second conductor layer 440), that is, having a buildup cured material layer and a buildup conductor layer. The inductor substrate 100 also includes an inner layer substrate 200 .

As shown in FIG. 14, the first cured layer 320 and the second cured layer 340 constitute the magnetic part 300 which can be viewed as an integrated cured layer. Therefore, the coil-shaped conductive structure 400 is provided so that at least a portion thereof is embedded in the magnetic portion 300 . That is, in the inductor substrate 100 of the present embodiment, the inductor element includes the coil-shaped conductive structure 400 and the magnetic portion 300 extending in the thickness direction of the magnetic portion 300 and surrounded by the coil-shaped conductive structure 400. It is composed of a core part which is a part of the

As shown in FIG. 15 as an example, the first conductor layer 420 has a spiral wiring portion for forming the coil-shaped conductive structure 400 and a rectangular wiring portion electrically connected to the through-hole wiring 220a. land 420a. In the illustrated example, the spiral wiring portion includes a bent portion that bends at right angles to the straight portion and a bypass portion that bypasses the land 420a. In the illustrated example, the spiral wiring portion of the first conductor layer 420 has a substantially rectangular outline as a whole, and has a shape that is wound counterclockwise from the center toward the outside.

Similarly, a second conductor layer 440 is provided on the first cured material layer 320 . The second conductor layer 440 includes a spiral wiring portion for forming the coil-shaped conductive structure 400 . In FIG. 13 or FIG. 14, the spiral wiring portion includes a linear portion and a bent portion bent at right angles. In FIG. 13 or FIG. 14, the spiral wiring portion of the second conductor layer 44 has a generally rectangular outline as a whole, and has a shape that is wound clockwise from the center toward the outside.

Such an inductor substrate can be used as a wiring board for mounting electronic components such as semiconductor chips, and can also be used as a (multilayer) printed wiring board using such a wiring board as an inner layer substrate. Also, such a wiring board can be used as chip inductor components obtained by individualizing, and can also be used as a printed wiring board in which the chip inductor components are surface-mounted.

Moreover, using such a wiring board, various types of semiconductor devices can be manufactured. A semiconductor device containing such a wiring board can be suitably used for electrical appliances (eg, computers, mobile phones, digital cameras, televisions, etc.) and vehicles (eg, motorcycles, automobiles, trains, ships, aircraft, etc.). .

EXAMPLES Hereinafter, the present invention will be specifically described with reference to Examples. The invention is not limited to these examples. In the following, "%" representing the amount means "% by mass" unless otherwise specified. Unless otherwise specified, the temperature condition is room temperature (23° C.). Unless otherwise specified, the pressure condition is normal pressure (1 atm).

<Example 1>
Flat magnetic powder a (“PST-4” manufactured by Sanyo Special Steel Co., Ltd., Fe—Si—Al alloy powder, 10% particle size (D ₁₀ ) 5.8 μm, average particle size (D ₅₀ ) 37 μm, 90% Particle diameter (D ₉₀ ) 75 μm, aspect ratio 2.0, average thickness 1.7 μm, oblateness 22, average minor axis length 21 μm, tap density 2.56 g/cm ³ ) is 50 parts by mass, spherical magnetic powder a (“AW2-08PF3” manufactured by Epson Atmix, Fe—Si—Cr alloy powder, 10% particle size (D ₁₀ ) 1.7 μm, average particle size (D ₅₀ ) 3.1 μm, 90% particle size (D ₉₀ ) 5.2 μm, aspect ratio 1.1, average thickness 3.1 μm, oblateness 1.1) 39 parts by mass, spherical magnetic powder b (“M001” manufactured by Powdertech Co., Ltd., Mn ferrite powder, 10% grain Diameter (D ₁₀ ) 0.05 μm, average particle size (D ₅₀ ) 0.12 μm, 90% particle size (D ₉₀ ) 1.1 μm, aspect ratio 1.1, average thickness 0.1 μm, oblateness 1.1) 39 parts by mass of epoxy resin (“ZX-1059” manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin) 13 parts by mass, phenol resin (DIC “LA-7054” , melamine-modified phenolic novolac resin, MEK solution with 60% non-volatile components) 14 parts by mass, phenoxy resin ("YX7553BH30" manufactured by Mitsubishi Chemical Corporation, methyl ethyl ketone with 30% non-volatile components: cyclohexanone = 1: 1 solution, special skeleton phenoxy resin ) and 0.1 parts by mass of curing accelerator a (“TBP-DA” manufactured by Hokko Chemical Industry Co., Ltd., phosphorus-based curing accelerator), and dispersed uniformly with a high-speed rotating mixer to form a resin composition. prepared.

<Example 2>
The amount of flat magnetic powder a ("PST-4" manufactured by Sanyo Special Steel Co., Ltd.) was changed from 50 parts by mass to 79 parts by mass, and spherical magnetic powder a ("AW2-08PF3" manufactured by Epson Atmix Co., Ltd. ”) was changed from 39 parts by mass to 61 parts by mass, and the amount of spherical magnetic powder b (“M001” manufactured by Powdertech Co., Ltd.) was changed from 39 parts by mass to 79 parts by mass. A resin composition was prepared in the same manner as in Example 1.

<Example 3>
The amount of flat magnetic powder a ("PST-4" manufactured by Sanyo Special Steel Co., Ltd.) was changed from 50 parts by mass to 87 parts by mass, and spherical magnetic powder a ("AW2-08PF3" manufactured by Epson Atmix Co., Ltd. ”) was changed from 39 parts by mass to 67 parts by mass, and the amount of spherical magnetic powder b (“M001” manufactured by Powdertech Co., Ltd.) was changed from 39 parts by mass to 87 parts by mass. A resin composition was prepared in the same manner as in Example 1.

<Example 4>
Instead of 50 parts by mass of flat magnetic powder a ("PST-4" manufactured by Sanyo Special Steel Co., Ltd.), flat magnetic powder b ("FME3D-AH" manufactured by Sanyo Special Steel Co., Ltd., Fe-Si-Al alloy Powder, 10% particle size (D ₁₀ ) 15 μm, average particle size (D ₅₀ ) 42 μm, 90% particle size (D ₉₀ ) 107 μm, aspect ratio 2.0, thickness 0.1 μm, oblateness 480, average minor axis length 18 μm, tap density 0.73 g/cm ³ ) is used, and the amount of spherical magnetic powder a ("AW2-08PF3" manufactured by Epson Atmix) is changed from 39 parts by mass to 58 parts by mass. A resin composition was prepared in the same manner as in Example 1, except that the amount of spherical magnetic powder b ("M001" manufactured by Powdertech Co., Ltd.) was changed from 39 parts by mass to 73 parts by mass.

<Example 5>
The amount of flat magnetic powder a (manufactured by Sanyo Special Steel Co., Ltd. "PST-4") was changed from 50 parts by mass to 34 parts by mass, and spherical magnetic powder a (manufactured by Epson Atmix Co., Ltd. "AW2-08PF3 ”) was changed from 39 parts by mass to 26 parts by mass, the amount of spherical magnetic powder b (“M001” manufactured by Powdertech Co., Ltd.) was changed from 39 parts by mass to 26 parts by mass, and epoxy resin ( "ZX-1059" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) was changed from 13 parts by mass to 7 parts by mass, and instead of 0.1 parts by mass of curing accelerator a ("TBP-DA" manufactured by Hokko Chemical Industry Co., Ltd.) Using 1 part by mass of curing accelerator b ("2MZA-PW" manufactured by Shikoku Kasei Co., Ltd., imidazole-based curing accelerator), 14 parts by mass of phenolic resin ("LA-7054" manufactured by DIC) without using phenoxy resin ("YX7553BH30" manufactured by Mitsubishi Chemical Corporation) A resin composition was prepared in the same manner as in Example 1, except that 12 parts by mass was not used.

<Example 6>
The amount of spherical magnetic powder a (“AW2-08PF3” manufactured by Epson Atmix) was changed from 39 parts by mass to 38 parts by mass, and spherical magnetic powder b (“M001” manufactured by Powdertech) was used. The amount was changed from 39 parts by mass to 38 parts by mass, the amount of epoxy resin (“ZX-1059” manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) was changed from 13 parts by mass to 7 parts by mass, and the curing accelerator a (Hokko Chemical Industry "TBP-DA" manufactured by Co., Ltd.) Instead of 0.1 part by mass of curing accelerator b ("2MZA-PW" manufactured by Shikoku Kasei Co., Ltd., imidazole curing accelerator) 1 part by mass, phenol resin (manufactured by DIC A resin composition was prepared in the same manner as in Example 1, except that 14 parts by mass of "LA-7054") was not used and 12 parts by mass of phenoxy resin (manufactured by Mitsubishi Chemical Corporation "YX7553BH30") was not used. .

<Example 7>
The amount of flat magnetic powder a ("PST-4" manufactured by Sanyo Special Steel Co., Ltd.) was changed from 50 parts by mass to 40 parts by mass, and spherical magnetic powder a ("AW2-08PF3" manufactured by Epson Atmix Co., Ltd. ”) was changed from 39 parts by mass to 20 parts by mass, the amount of epoxy resin (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. “ZX-1059”) was changed from 13 parts by mass to 5 parts by mass, and the curing accelerator a ("TBP-DA" manufactured by Hokko Chemical Industry Co., Ltd.) Instead of 0.1 parts by mass of curing accelerator b ("2MZA-PW" manufactured by Shikoku Kasei Co., Ltd., imidazole curing accelerator) 0.4 parts by mass, 2 parts by mass of a dispersant ("SC-1015F", polyoxyalkylene dispersant manufactured by NOF CORPORATION) and 2 parts by mass of a cyclic ketone solvent ("Cyclohexanone" manufactured by Junsei Chemical Co., Ltd.) are further added to form a spherical magnetic powder b. ("M001" manufactured by Powdertech) 39 parts by mass are not used, phenol resin ("LA-7054" manufactured by DIC) 14 parts by mass are not used, and phenoxy resin ("YX7553BH30" manufactured by Mitsubishi Chemical Corporation) 12 parts by mass A resin composition was prepared in the same manner as in Example 1, except that parts were not used.

<Comparative Example 1>
The amount of flat magnetic powder a ("PST-4" manufactured by Sanyo Special Steel Co., Ltd.) was changed from 50 parts by mass to 55 parts by mass, and epoxy resin ("ZX-1059" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) was used. The amount was changed from 13 parts by mass to 3 parts by mass, the amount of phenolic resin ("LA-7054" manufactured by DIC) was changed from 14 parts by mass to 4 parts by mass, and the phenoxy resin ("YX7553BH30" manufactured by Mitsubishi Chemical Co., Ltd. ) was changed from 12 parts by mass to 3 parts by mass, and 39 parts by mass of spherical magnetic powder a (“AW2-08PF3” manufactured by Epson Atmix) was not used, and spherical magnetic powder b (powder A resin composition was prepared in the same manner as in Example 1, except that 39 parts by mass of "M001" manufactured by TEC Co., Ltd. was not used.

<Comparative Example 2>
Spherical magnetic powder a ("AW2-08PF3" manufactured by Epson Atmix) was changed from 39 parts by weight to 65 parts by weight, and epoxy resin ("ZX-1059" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) was added from 13 parts by weight to 3 parts by weight. , the amount of phenol resin ("LA-7054" manufactured by DIC) was changed from 14 parts by mass to 4 parts by mass, and the amount of phenoxy resin ("YX7553BH30" manufactured by Mitsubishi Chemical Corporation) was changed from 12 parts by mass. Change to 3 parts by mass, add 2 parts by mass of cyclic ketone solvent (“Cyclohexanone” manufactured by Junsei Chemical Co., Ltd.), and use 50 parts by mass of flat magnetic powder a (“PST-4” manufactured by Sanyo Special Steel Co., Ltd.) A resin composition was prepared in the same manner as in Example 1, except that 39 parts by mass of spherical magnetic powder b ("M001" manufactured by Powdertech Co., Ltd.) was not used.

<Calculation of oblateness>
In observation with a scanning electron microscope, randomly select 50 magnetic powders, measure the length of the longest line segment connecting the longest two points on the contour of the particles in plan view, and average the length The average long axis length was calculated from (number average). In addition, the magnetic powder is embedded in a polyester resin (JP-21111001, unsaturated polyester, manufactured by Marumoto Struers Co., Ltd.), cured at 80° C. for 30 minutes, and then polished using a polishing device (STRUERS-S5629B, manufactured by Struers Co., Ltd.). It was polished (SiC-sanding paper #4000, manufactured by Struers), and the polished surface was observed with a scanning electron microscope. For 50 particles randomly extracted from the magnetic powder, the thickness Y in the thickness direction of the magnetic powder was measured based on the scanning electron microscope image, and the average thickness was calculated from the maximum value Ym and minimum value Yn. ((Ym+Yn)/2) was calculated, and the flattening ratio (average major axis length/average thickness) was calculated.

<Calculation of aspect ratio>
In observation with a scanning electron microscope, randomly select 50 magnetic powders, measure the length of the longest line segment connecting the longest two points on the contour of the particles in plan view, and average the length The average long axis length was calculated from (number average). At the same time, the length of the short side of a rectangle with the smallest area circumscribing the contour of the particle and having the long side parallel to the longest line segment is drawn, and the average length of the short axis is calculated from the average value. did. The aspect ratio was calculated based on the value obtained by dividing the average long axis length by the average short axis length.

<Calculation of 10% particle size (D ₁₀ ), average particle size (D ₅₀ ), and 90% particle size (D ₉₀ )>
A measurement sample was obtained by dispersing magnetic powder in pure water using ultrasonic waves. 10% particle size (D ₁₀ ), 50% particle size (average particle size) (D ₅₀ ), and 90% particle size (D ₉₀ ) were calculated on a volume basis.

<Test Example 1: Evaluation of pasting and filming>
The fluidity of the resin compositions prepared in Examples and Comparative Examples was confirmed, and the resin compositions of Examples 1 to 7 and Comparative Example 2, which were pasty and had coatability, were formed into films. As a support, a polyethylene terephthalate (PET) film (“PET501010” manufactured by Lintec Corporation, thickness 50 μm) treated with a silicone release agent was prepared. Each resin composition was uniformly coated on the release surface of the PET film with a doctor blade so that the thickness of the resin composition layer after drying was 100 μm, to obtain a resin sheet. Pasting and filming of the resin composition were evaluated according to the following evaluation criteria.

(Evaluation criteria for pasting)
"Good": Fluid pasty with coatability.
"X": No fluidity, coating not possible.

(Evaluation criteria for film formation)
"Good": No holes, film thickness is uniform.
"Poor": Holes are formed and the thickness of the film is non-uniform. Or, it has no fluidity and cannot be made into a film.

<Test Example 2: Measurement and Evaluation of Relative Permeability>
The resin sheet obtained in Test Example 1 was heated at 190° C. for 90 minutes to thermally cure the resin composition layer, and the support was peeled off to obtain a sheet-like cured product. The obtained cured product was cut into a test piece having a width of 5 mm and a length of 18 mm to obtain an evaluation sample. The relative magnetic permeability (μ') of this evaluation sample was measured at a room temperature of 23° C. at a measurement frequency of 10 MHz by the 3-turn coil method using Agilent Technologies (manufactured by Agilent Technologies, "HP8362B"). The relative magnetic permeability was evaluated according to the following evaluation criteria.

(Evaluation criteria for relative magnetic permeability)
"◯": Relative permeability is 11 or more.
"x": Relative permeability is less than 11.
"No description": Cannot be made into a film and cannot be measured.

<Test Example 3: Measurement of Viscosity>
Among the resin compositions obtained in Examples and Comparative Examples, the pasty resin compositions of Examples 1 to 7 and Comparative Example 2 were kept at a temperature of 25 ± 2 ° C. and measured with an E-type viscometer (Toki Sangyo Viscosity measurement (Pa·s) was performed using “RE-80U” manufactured by Co., Ltd., 3°×R9.7 cone, rotation speed 5 rpm).

Table 1 below shows the non-volatile components and their contents of the resin compositions of Examples and Comparative Examples, and the measurement results and evaluation results of Test Examples.

From the above, (A) magnetic powder and (B) thermosetting resin are included, and component (A) is (A-1) flat magnetic powder and (A-2) spherical magnetic powder. (A-1) A magnetic material that can be easily made into a paste or a film and has excellent relative magnetic permeability by using a resin composition in which flat magnetic powder has an average minor axis length of 1 μm or more. was found to be obtained.

10 core substrate 11 support substrate 12 first metal layer 13 second metal layer 14 through hole 20 plating layer 30a resin composition 30 cured product 40 conductor layer 41 pattern conductor layer 100 circuit board 200 inner layer substrate 200a first main surface 200b second second Main surface 220 through hole 220a through hole wiring 240 external terminal 300 magnetic part 310 resin sheet 320a resin composition layer 320 first cured layer 330 support 340 second cured layer 360 via hole 360a via hole wiring 400 coil-like conductivity Structure 420 First conductor layer 420a Land 440 Second conductor layer

Claims (16)

A resin composition containing (A) a magnetic powder and (B) a thermosetting resin,
(A) component contains (A-1) flat magnetic powder and (A-2) spherical magnetic powder,
(A-1) The resin composition, wherein the component has an average minor axis length of 1 μm or more. 2. The resin composition according to claim 1, wherein component (A-1) has an oblateness of 2 or more and component (A-2) has an oblateness of less than 2. 3. The resin composition according to claim 1, wherein component (A-1) has an average particle size of 10 μm to 100 μm. The resin composition according to any one of claims 1 to 3, wherein component (A-2) has an average particle size of 0.1 µm to 40 µm. Any one of claims 1 to 4, wherein the mass ratio of component (A-1) to component (A-2) (component (A-1)/component (A-2)) is 0.4 to 2.3. 1. The resin composition according to claim 1. The resin composition according to any one of claims 1 to 5, wherein the content of component (A) is 25% by volume to 75% by volume when the non-volatile component in the resin composition is 100% by volume. . The resin composition according to any one of claims 1 to 6, wherein the content of component (A) is 70% by mass to 96% by mass when the non-volatile component in the resin composition is 100% by mass. . The resin composition according to any one of claims 1 to 7, wherein component (B) comprises (B-1) an epoxy resin. The resin composition according to any one of claims 1 to 8, further comprising (C) a curing accelerator. The resin composition according to any one of claims 1 to 9, wherein the cured product of the resin composition has a relative magnetic permeability (μ') of 11 or more when measured at a measurement frequency of 10 MHz and 23°C. The resin composition according to any one of claims 1 to 10, which has a viscosity of 0.05 Pa·s to 1500 Pa·s at 25°C. A resin sheet comprising a support and a resin composition layer formed of the resin composition according to any one of claims 1 to 11 provided on the support. A cured product of the resin composition according to any one of claims 1 to 11. A circuit board comprising a substrate having through holes and a cured product of the resin composition according to any one of claims 1 to 11 filled in the through holes. A circuit board comprising a cured product layer which is a cured product of the resin composition according to any one of claims 1 to 11. An inductor substrate comprising the circuit substrate according to claim 14 or 15.

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