Resin Composition

Abstract

The objective of this invention is to provide a resin composition for obtaining magnetic materials with excellent mechanical strength and relative magnetic permeability. The solution of this invention lies in a resin composition comprising (A) magnetic powder and (B) a thermosetting resin, wherein component (A) comprises (A-1) ferrite powder with an average particle size of 0.8 μm or less and (A-2) magnetic powder with an average particle size of 1.5 μm or more, and the volume ratio of component (A-2) to component (A-1) ((A-2) component / (A-1) component) is 0.8 to 34.0.

Description

Technical Field

[0001] This invention relates to resin compositions containing magnetic powders. It further relates to cured products, resin sheets, circuit boards, and inductor substrates obtained using the resin compositions. Background Technology

[0002] Inductor components are widely used in information terminals such as mobile phones and smartphones. Previously, inductor components were mounted independently on a substrate, but in recent years, methods have been developed to form coils through conductor patterns on the substrate and to house the inductor components within the substrate. As a method for housing inductor components within the substrate, a known method is to form a cured layer by screen printing a magnetic material containing magnetic powder onto a substrate containing wiring (Patent Documents 1 and 2). In recent years, to further improve the performance of inductor components, there has been a demand for further improving the magnetic properties of magnetic materials. One method for improving the magnetic properties of magnetic materials is to increase the content of magnetic powder in the material. For example, it is known to use two or more types of magnetic metal powders with different average particle sizes to increase the powder filling rate and improve the magnetic properties of magnetic materials (Patent Document 3).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 6-69058

[0006] Patent Document 2: Japanese Patent Application Publication No. 2017-63100

[0007] Patent document 3: Japanese Patent Application Publication No. 2019-220609. Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] However, there are limits to the improvement in relative permeability that can be achieved by increasing the fill rate. Furthermore, increasing the fill rate can lead to a tendency to damage the mechanical strength of the magnetic material, making it prone to cracking and other problems, thus reducing the production stability of inductor components.

[0010] The objective of this invention is to provide a resin composition for obtaining a magnetic material (cured product) with excellent mechanical strength and relative magnetic permeability.

[0011] Means used to solve problems

[0012] The inventors, through in-depth research to achieve the above-mentioned objective, discovered that in a thermosetting resin composition containing two types of magnetic powders with an average particle size of 0.8 μm or less and an average particle size of 1.5 μm or more, when ferrite powder is used as the magnetic powder with an average particle size of 0.8 μm or less in a specified proportion, it is unexpected that excellent relative magnetic permeability can be achieved while maintaining mechanical strength, thus completing the present invention.

[0013] That is, the present invention includes the following contents.

[0014] [1] A resin composition comprising (A) magnetic powder and (B) a thermosetting resin,

[0015] (A) The composition includes (A-1) ferrite powder with an average particle size of less than 0.8 μm and (A-2) magnetic powder with an average particle size of more than 1.5 μm.

[0016] The volume ratio of component (A-2) to component (A-1) (component (A-2) / component (A-1)) is 0.8 to 34.0.

[0017] [2] According to the resin composition described in [1] above, wherein the average particle size of component (A-2) is 10.0 μm or less.

[0018] [3] According to the resin composition described in [1] or [2] above, wherein the average particle size of component (A-2) is 2.5 μm or more.

[0019] [4] The resin composition according to any one of [1] to [3] above, wherein the average particle size of component (A-1) is 0.1 μm or more.

[0020] [5] The resin composition according to any one of [1] to [4] above, wherein the average particle size of component (A-1) is 0.3 μm or less.

[0021] [6] The resin composition according to any one of [1] to [5] above, wherein the ratio of the average particle size of component (A-2) to the average particle size of component (A-1) (component (A-2) / component (A-1)) is 10 or more.

[0022] [7] The resin composition according to any one of [1] to [6] above, wherein the (A-1) component contains ferrite powder containing at least one element selected from Mn, Zn, Mg, Sr and Ni in addition to Fe.

[0023] [8] The resin composition according to any one of [1] to [7] above, wherein component (A-2) comprises magnetic alloy powder.

[0024] [9] The resin composition according to any one of [1] to [8] above, wherein the content of component (A) is 50% by volume or more when the non-volatile component in the resin composition is 100% by volume.

[0025]

[10] The resin composition according to any one of [1] to [9] above, wherein the content of component (A) is 80% by volume or less when the non-volatile component in the resin composition is 100% by volume.

[0026]

[11] The resin composition according to any one of [1] to

[10] above, wherein the volume ratio of component (A-2) to component (A-1) (component (A-2) / component (A-1)) is 20.0 or less.

[0027]

[12] According to the resin composition described in

[11] above, the volume ratio of component (A-2) to component (A-1) (component (A-2) / component (A-1)) is 10.0 or less.

[0028]

[13] The resin composition according to any one of [1] to

[12] above, wherein component (B) comprises (B-1) epoxy resin.

[0029]

[14] The resin composition according to any one of [1] to

[13] above, wherein the tensile breaking strength of the cured resin composition, as determined according to JIS K7127, is 60 MPa or more.

[0030]

[15] The resin composition according to any one of [1] to

[14] above, wherein the relative magnetic permeability (μ') of the cured resin composition measured at a measurement frequency of 100 MHz and a temperature of 23°C is 10.0 or more.

[0031]

[16] The cured product of the resin composition described in any one of [1] to

[15] above.

[0032]

[17] A resin sheet comprising a support and a resin composition layer formed of any one of the resin compositions described in [1] to

[15] disposed on the support.

[0033]

[18] A circuit board having: a substrate having through holes, and a cured resin composition of any one of the above [1] to

[15] filled in the aforementioned through holes.

[0034]

[19] A circuit board comprising a cured layer which is a cured product of the resin composition described in any one of [1] to

[15] above.

[0035]

[20] An inductor substrate comprising the circuit substrate described in

[18] or

[19] above.

[0036] Effects of the Invention

[0037] According to the resin composition of the present invention, it is possible to obtain a magnetic material (cured product) with excellent mechanical strength and relative magnetic permeability. Attached Figure Description

[0038] [ Figure 1 ] Figure 1 This is a cross-sectional schematic diagram of a core substrate, which is an example of a method for manufacturing a circuit board according to the first embodiment.

[0039] [ Figure 2 ] Figure 2 This is a cross-sectional schematic diagram of a core substrate with through holes, which is an example of a method for manufacturing a circuit board according to the first embodiment.

[0040] [ Figure 3 ] Figure 3 This is a cross-sectional schematic diagram showing a core substrate in which a plating layer is formed in a through-hole, as an example of a method for manufacturing a circuit board according to the first embodiment.

[0041] [ Figure 4 ] Figure 4 This is a cross-sectional schematic diagram showing a core substrate in which a resin composition is filled in the through-holes, as an example of a method for manufacturing a circuit board according to the first embodiment.

[0042] [ Figure 5 ] Figure 5 This is a cross-sectional schematic diagram showing a core substrate in which the filled resin composition has been thermocured as an example of a method for manufacturing a circuit board according to the first embodiment.

[0043] [ Figure 6 ] Figure 6 This is a cross-sectional schematic diagram showing a core substrate after the cured material has been ground, as an example of a method for manufacturing a circuit board according to the first embodiment.

[0044] [ Figure 7 ] Figure 7 This is a cross-sectional schematic diagram showing a core substrate in which a conductor layer is formed on a polished surface, as an example of a method for manufacturing a circuit board according to the first embodiment.

[0045] [ Figure 8 ] Figure 8 This is a cross-sectional schematic diagram showing a core substrate with a patterned conductor layer formed, as an example of a method for manufacturing a circuit board according to the first embodiment.

[0046] [ Figure 9 ] Figure 9This is a cross-sectional schematic diagram of step (A) included in an example of the method for manufacturing a circuit board according to the second embodiment.

[0047] [ Figure 10 ] Figure 10 This is a cross-sectional schematic diagram of step (A) included in an example of the method for manufacturing a circuit board according to the second embodiment.

[0048] [ Figure 11 ] Figure 11 This is a cross-sectional schematic diagram of step (B) included in an example of the method for manufacturing a circuit board according to the second embodiment.

[0049] [ Figure 12 ] Figure 12 This is a cross-sectional schematic diagram of step (D) included in an example of the method for manufacturing a circuit board according to the second embodiment.

[0050] [ Figure 13 ] Figure 13 This is a plan view of an inductor component comprising a circuit board obtained by the manufacturing method of the circuit board according to the second embodiment, as an example, viewed from the thickness direction.

[0051] [ Figure 14 ] Figure 14 This is shown as an example in Figure 13 The diagram shows a cut-off end face of an inductor component comprising a circuit board obtained by the manufacturing method of the second embodiment, cut at the position indicated by the dashed line II-II.

[0052] [ Figure 15 ] Figure 15 This is a planar schematic diagram illustrating, as an example, the structure of the first conductor layer in an inductor component comprising a circuit board obtained by the manufacturing method of the circuit board of the second embodiment. Detailed Implementation

[0053] The present invention will now be described in detail according to its suitable embodiments. However, the present invention is not limited to the embodiments and examples described below, and can be implemented in any way without departing from the scope of the claims and their equivalents.

[0054] [Resin Composition]

[0055] The resin composition of the present invention comprises (A) magnetic powder and (B) thermosetting resin. The magnetic powder (A) comprises (A-1) ferrite powder with an average particle size of 0.8 μm or less and (A-2) magnetic powder with an average particle size of 1.5 μm or more. The volume ratio of the magnetic powder of component (A-2) to the ferrite powder of component (A-1) ((A-2) component / (A-1) component) is 0.8 to 34.0. By using such a resin composition, a magnetic material (cured product) with excellent mechanical strength and relative magnetic permeability can be obtained.

[0056] In addition to (A) magnetic powder and (B) thermosetting resin, the resin composition of the present invention may further contain optional components. Examples of optional components include (C) other additives and (D) organic solvents. The components contained in the resin composition will be described in detail below.

[0057] <(A) Magnetic Powder>

[0058] The resin composition of the present invention contains (A) magnetic powder. (A) magnetic powder imparts magnetism to the resin composition. In the resin composition of the present invention, (A) magnetic powder comprises (A-1) ferrite powder with an average particle size of 0.8 μm or less and (A-2) magnetic powder with an average particle size of 1.5 μm or more.

[0059] <(A-1) Ferrite powder with an average particle size of less than 0.8 μm>

[0060] In the resin composition of the present invention, (A) the magnetic powder comprises (A-1) ferrite powder with an average particle size of 0.8 μm or less. Ferrite powder refers to magnetic powder containing a composite oxide with iron oxide as the main component. The ferrite powder of component (A-1) can be used alone or in combination with two or more types. Ferrite powder is known to be chemically stable, highly corrosion-resistant, low flammability, difficult to demagnetize, and generally inexpensive and readily available.

[0061] The ferrite powder of component (A-1) can be any of hard ferrite powder or soft ferrite powder. In one embodiment, from the viewpoint of significantly obtaining the effects of the present invention, soft ferrite powder is preferred. The ferrite powder of component (A-1) can be any of spinel ferrite powder, hexagonal ferrite powder, or garnet ferrite powder. In one embodiment, from the viewpoint of significantly obtaining the effects of the present invention, spinel ferrite powder is preferred.

[0062] In addition to Fe, the ferrite powder with composition (A-1) may also contain at least one element selected from Mn, Zn, Mg, Sr, Ni, Cu, Ba, Co, Ca, Al, Li, Ti, Pb, Cd, etc. In one embodiment, the ferrite powder with composition (A-1) preferably contains at least one element selected from Mn, Zn, Mg, Sr, and Ni in addition to Fe.

[0063] Examples of ferrite powders with (A-1) composition include Fe-Mn ferrite powders, Mg-Zn ferrite powders, Mn ferrite powders, Mn-Zn ferrite powders, Mn-Mg ferrite powders, Cu-Zn ferrite powders, Mg-Sr ferrite powders, Mn-Mg-Sr ferrite powders, Ni-Zn ferrite powders, Ni-Zn-Cu ferrite powders, Ba-Zn ferrite powders, Ba-Mg ferrite powders, Ba-Ni ferrite powders, Ba-Co ferrite powders, Ba-Ni-Co ferrite powders, and Y-based ferrite powders. The ferrite powder of composition (A-1) preferably includes ferrite powder selected from Mn-based ferrite powder, Mn-Zn-based ferrite powder, Mg-Sr-based ferrite powder, Mn-Mg-Sr-based ferrite powder, and Ni-Zn-based ferrite powder.

[0064] The ferrite powder of component (A-1) is preferably a nearly spherical or nearly ellipsoidal particle. The ratio (b / a) of the major axis (b) to the minor axis (a) of the ferrite powder particles of component (A-1) is preferably 2 or less, more preferably 1.5 or less, and even more preferably 1.2 or less.

[0065] The average particle size of the ferrite powder of composition (A-1) is 0.8 μm or less. From the viewpoint of achieving more significant effects of the invention, it is preferably 0.6 μm or less, more preferably 0.4 μm or less, further preferably 0.3 μm or less, and particularly preferably 0.2 μm or less. The lower limit of the average particle size of the ferrite powder of composition (A-1) is not particularly limited, but it is preferably 0.01 μm or more, more preferably 0.05 μm or more, further preferably 0.1 μm or more, and particularly preferably 0.12 μm or more. The average particle size of the ferrite powder of composition (A-1) can be the median diameter based on volume. This average particle size can be determined by laser diffraction and scattering based on Mie scattering theory. Specifically, a particle size distribution can be prepared on a volume basis using a laser diffraction and scattering particle size distribution measuring device, and the median diameter can be recorded as the average particle size for measurement. The sample used for measurement can preferably be a substance in which the powder is dispersed in water by ultrasonication. As a laser diffraction scattering particle size distribution measuring device, the "LA-500" manufactured by Horiba Corporation and the "SALD-2200" manufactured by Shimadzu Corporation can be used.

[0066] The true specific gravity of ferrite powder with composition (A-1) can be, for example, 4.7~5.2 g / cm³. 3 .

[0067] Ferrite powders with composition (A-1) are commercially available and can be used directly, and two or more types can be used together. Specific examples of commercially available ferrite powders with composition (A-1) include "M001", "MZ001", "E001", and "NZ001" manufactured by Powdertech Co., Ltd.

[0068] From the viewpoint of achieving a more significant effect of the invention, the content (volume %) of ferrite powder in component (A-1) is preferably 0.5 vol% or more, 1 vol% or more, more preferably 2 vol% or more, or 3 vol% or more when the non-volatile component in the resin composition is 100 vol%. From the viewpoint of further improving the breaking strength, it is further preferably 5 vol% or more, 10 vol% or more, particularly preferably 15 vol% or more, or 20 vol% or more. Furthermore, from the viewpoint of achieving a more significant effect of the invention, the upper limit is preferably 50 vol% or less, 45 vol% or less, more preferably 40 vol% or less, or 35 vol% or less when the non-volatile component in the resin composition is 100 vol%. From the viewpoint of further improving the magnetic permeability, it is further preferably 30 vol% or less, particularly preferably 27 vol% or less.

[0069] From the viewpoint of achieving a more significant effect of the invention, the content (mass%) of ferrite powder in component (A-1), when the non-volatile component in the resin composition is 100% by mass, is preferably 0.5% by mass or more, 1% by mass or more, more preferably 2% by mass or more, or 3% by mass or more. From the viewpoint of further improving the breaking strength, it is further preferably 5% by mass or more, 10% by mass or more, 15% by mass or more, particularly preferably 20% by mass or more, or 25% by mass or more. Furthermore, from the viewpoint of achieving a more significant effect of the invention, when the non-volatile component in the resin composition is 100% by mass, it is preferably 70% by mass or less, 60% by mass or less, more preferably 50% by mass or less, or 40% by mass or less. From the viewpoint of further improving the magnetic permeability, it is further preferably 35% by mass or less, particularly preferably 30% by mass or less.

[0070] <(A-2) Magnetic powder with an average particle size of 1.5 μm or larger>

[0071] In the resin composition of the present invention, (A) the magnetic powder comprises (A-2) magnetic powder with an average particle size of 1.5 μm or more. The type of magnetic powder in component (A-2) is not particularly limited, and widely known magnetic powders can be used. Component (A-2) may be a single type of magnetic powder, or two or more types may be used in combination.

[0072] The magnetic powder in component (A-2) can be either soft magnetic powder or hard magnetic powder. In one embodiment, from the viewpoint of significantly obtaining the effects of the present invention, soft magnetic powder is preferred. The magnetic powder in component (A-2) can be, for example, magnetic metal oxide powder or magnetic metal powder.

[0073] As magnetic metal oxide powders, there are no particular limitations. Examples include Fe-Mn ferrite powders, Mg-Zn ferrite powders, Mn ferrite powders, Mn-Zn ferrite powders, Mn-Mg ferrite powders, Cu-Zn ferrite powders, Mg-Sr ferrite powders, Mn-Mg-Sr ferrite powders, Ni-Zn ferrite powders, Ni-Zn-Cu ferrite powders, Ba-Zn ferrite powders, Ba-Mg ferrite powders, Ba-Ni ferrite powders, Ba-Co ferrite powders, Ba-Ni-Co ferrite powders, Y-based ferrite powders, etc.; iron oxide powder (III), iron tetroxide powder, etc.

[0074] As for magnetic metal powders, there are no particular limitations. Examples include pure iron powder; Fe-Si alloy powders, Fe-Si-Al alloy powders, Fe-Cr alloy powders, Fe-Si-Cr alloy powders, Fe-Ni-Cr alloy powders, Fe-Cr-Al alloy powders, Fe-Ni alloy powders, Fe-Ni-Mo alloy powders, Fe-Ni-Mo-Cu alloy powders, Fe-Co alloy powders, Fe-Ni-Co alloy powders, Co-based amorphous alloy powders, and other crystalline or amorphous magnetic alloy powders.

[0075] The magnetic powder of composition (A-2) preferably includes at least one type of magnetic powder selected from ferrite powder and magnetic alloy powder. From the viewpoint of further improving the magnetic permeability, it is preferred to include at least one type of magnetic alloy powder, and particularly preferred to include at least one type of magnetic alloy powder selected from Fe-Si-Cr alloy powder and Fe-Ni alloy powder.

[0076] The magnetic powder of component (A-2) is preferably a nearly spherical or nearly ellipsoidal particle. The ratio (b / a) of the major axis (b) to the minor axis (a) of the magnetic powder particles of component (A-2) is preferably 4 or less, more preferably 3 or less, and even more preferably 2 or less.

[0077] The magnetic powder of component (A-2) has an average particle size of 1.5 μm or more. From the viewpoint of achieving more significant effects of the invention, it is preferably 2.0 μm or more, more preferably 2.5 μm or more, further preferably 2.7 μm or more, and particularly preferably 2.8 μm or more. The upper limit of the average particle size of the magnetic powder of component (A-2) is not particularly limited. From the viewpoint of further suppressing magnetic loss, it is preferably 10.0 μm or less, more preferably 7.0 μm or less, further preferably 5.0 μm or less, and particularly preferably 3.5 μm or less. The average particle size of the magnetic powder of component (A-2) can be the median diameter based on volume. The average particle size of the magnetic powder of component (A-2) can be determined by the same method as the average particle size of the ferrite powder of component (A-1).

[0078] From the viewpoint that the ratio of the average particle size of the magnetic powder of component (A-2) to the average particle size of the ferrite powder of component (A-1) ((A-2) component / (A-1) component) is to obtain more significant effects of the invention, it is preferably 10 or more, more preferably 15 or more, and further preferably 50 or less, more preferably 30 or less.

[0079] The specific surface area of ​​the magnetic powder with component (A-2) is not particularly limited, but is preferably 0.05 m². 2 / g or more, more preferably 0.1m 2 / g or more, more preferably 0.3m 2 / g or more. Furthermore, 30m is preferred. 2 / g or less, more preferably 20m 2 / g or less, more preferably 15m 2 / g or less. (A) The specific surface area of ​​magnetic powder can be determined by the BET method.

[0080] The true specific gravity of the magnetic powder with component (A-2) can be, for example, 4~10 g / cm³. 3 .

[0081] As the magnetic powder for component (A-2), commercially available magnetic powders can be used. Specific examples of commercially available magnetic powders that can be used include "MZ05" manufactured by Powdertech Co., Ltd., and "AW08PF3F" manufactured by Apsontomic Co., Ltd. One type of magnetic powder can be used alone, or two or more types can be used in combination.

[0082] From the viewpoint of achieving a more significant effect of the invention, the content (volume %) of the magnetic powder in component (A-2), when the non-volatile component in the resin composition is 100 vol%, is preferably 10 vol% or more, 20 vol% or more, more preferably 25 vol% or more, 30 vol% or more, or 35 vol% or more. From the viewpoint of further improving the magnetic permeability, it is further preferably 37 vol% or more, and particularly preferably 39 vol% or more. Furthermore, from the viewpoint of achieving a more significant effect of the invention, when the non-volatile component in the resin composition is 100 vol%, it is preferably 80 vol% or less, 75 vol% or less, more preferably 70 vol% or less, or 65 vol% or less. From the viewpoint of further improving the breaking strength, it is further preferably 60 vol% or less, and particularly preferably 55 vol% or less.

[0083] From the viewpoint of achieving a more significant effect of the invention, the content (mass%) of the magnetic powder in component (A-2), when the non-volatile component in the resin composition is 100% by mass, is preferably 20% by mass or more, 30% by mass or more, more preferably 40% by mass or more, or 50% by mass or more. From the viewpoint of further improving the magnetic permeability, it is more preferably 60% by mass or more, and more preferably 63% by mass or more. Furthermore, from the viewpoint of achieving a more significant effect of the invention, when the non-volatile component in the resin composition is 100% by mass, it is preferably 95% by mass or less, more preferably 90% by mass or less. From the viewpoint of further improving the breaking strength, it is more preferably 80% by mass or less, and particularly preferably 70% by mass or less.

[0084] The volume ratio of component (A-2) to component (A-1) (component (A-2) / component (A-1)) is 0.8 or more. From the viewpoint of achieving a more significant effect of the invention, it is preferably 0.9 or more, more preferably 1.0 or more. From the viewpoint of further improving the magnetic permeability, it is further preferably 1.1 or more, 1.2 or more, particularly preferably 1.3 or more, or 1.4 or more. Furthermore, its upper limit is 34.0 or less. From the viewpoint of achieving a more significant effect of the invention, it is preferably 30.0 or less, 25.0 or less, more preferably 20.0 or less, or 15.0 or less. From the viewpoint of further improving the fracture strength, it is further preferably 10.0 or less, 5.0 or less, particularly preferably 3.0 or less, or 2.5 or less.

[0085] (A) The content (volume %) of magnetic powder is not particularly limited. From the viewpoint of achieving a more significant effect of the invention, when the non-volatile component in the resin composition is 100% by volume, it is preferably 30% by volume or more, more preferably 40% by volume or more, further preferably 50% by volume or more, 55% by volume or more, particularly preferably 60% by volume or more, 62% by volume or more, or 65% by volume or more. Furthermore, from the viewpoint of achieving a more significant effect of the invention, when the non-volatile component in the resin composition is 100% by volume, it is preferably 90% by volume or less, more preferably 85% by volume or less, further preferably 80% by volume or less, and particularly preferably 75% by volume or less.

[0086] (A) The content (mass%) of magnetic powder is not particularly limited. From the viewpoint of achieving a more significant effect of the invention, when the non-volatile component in the resin composition is 100% by mass, it is preferably 50% by mass or more, 60% by mass or more, more preferably 70% by mass or more, 75% by mass or more, further preferably 80% by mass or more, 85% by mass or more, particularly preferably 90% by mass or more, or 92% by mass or more. Furthermore, from the viewpoint of achieving a more significant effect of the invention, when the non-volatile component in the resin composition is 100% by mass, it is preferably 97% by mass or less, more preferably 95% by mass or less, further preferably 94% by mass or less, and particularly preferably 93% by mass or less.

[0087] <(A-3) Optional Magnetic Powder>

[0088] (A) The composition may include, in addition to (A-1) and (A-2), optional magnetic powders of (A-3). Optional magnetic powders of (A-3) may be, for example, magnetic metal oxide powders, magnetic metal powders, etc.

[0089] The lower the content of the optional magnetic powder (A-3) in component (A), the better. The content of the optional magnetic powder (A-3) relative to 100% by volume of the total components (A) is preferably 5% by volume or less, more preferably 2% by volume or less, and even more preferably 1% by volume or less. Furthermore, relative to 100% by mass of the total components (A), it is preferably 5% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less. Component (A) is particularly preferably free of the optional magnetic powder (A-3) (0% by volume, 0% by mass). That is, component (A) is particularly preferably composed only of components (A-1) and (A-2).

[0090] <(B) Thermosetting Resins>

[0091] The resin composition of the present invention contains (B) a thermosetting resin. Examples of (B) thermosetting resins include epoxy resins, epoxy acrylate resins, polyurethane acrylate resins, polyurethane resins, cyanate ester resins, polyimide resins, benzoxazine resins, unsaturated polyester resins, phenolic resins, melamine resins, silicone resins, phenoxy resins, etc.

[0092] (B) The content (mass%) of the thermosetting resin is not particularly limited. From the viewpoint of achieving a more significant effect of the invention, when the non-volatile component in the resin composition is 100% by mass, it is preferably 0.1% by mass or more, more preferably 1% by mass or more, further preferably 3% by mass or more, and particularly preferably 5% by mass or more. Furthermore, from the viewpoint of achieving a more significant effect of the invention, when the non-volatile component in the resin composition is 100% by mass, it is preferably 50% by mass or less, more preferably 30% by mass or less, further preferably 20% by mass or less, and particularly preferably 10% by mass or less.

[0093] <(B-1) Epoxy Resin>

[0094] The resin composition of the present invention is a (B) thermosetting resin, preferably containing (B-1) epoxy resin. (B-1) epoxy resin refers to a resin having epoxy groups.

[0095] Examples of (B-1) epoxy resins include, for instance, bixylenol-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, bisphenol AF-type epoxy resins, dicyclopentadiene-type epoxy resins, triphenol-type epoxy resins, naphthol phenolic varnish-type epoxy resins, phenol phenolic varnish-type epoxy resins, tert-butyl-catechol-type epoxy resins, naphthalene-type epoxy resins, naphthol-type epoxy resins, anthracene-type epoxy resins, glycidylamine-type epoxy resins, glycidyl ester-type epoxy resins, cresol phenolic varnish-type epoxy resins, biphenyl-type epoxy resins, linear aliphatic epoxy resins, epoxy resins with a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spirocyclic epoxy resins, cyclohexane-type epoxy resins, cyclohexanediethanol-type epoxy resins, naphthyl ether-type epoxy resins, tris(hydroxymethyl)-type epoxy resins, and tetraphenylethane-type epoxy resins. Epoxy resin can be used alone or in combination of two or more types.

[0096] The resin composition, as (B-1) epoxy resin, preferably comprises an epoxy resin having two or more epoxy groups per molecule. From the viewpoint of significantly obtaining the desired effects of the present invention, the proportion of epoxy resin having two or more epoxy groups per molecule is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more, relative to 100% by mass of the non-volatile components of the (B-1) epoxy resin.

[0097] (B-1) The epoxy resin includes an epoxy resin that is liquid at 25°C (hereinafter sometimes referred to as "liquid epoxy resin") and an epoxy resin that is solid at 25°C (hereinafter sometimes referred to as "solid epoxy resin"). The resin composition of the present invention, as (B-1) epoxy resin, may contain only liquid epoxy resin, or may contain a combination of liquid epoxy resin and solid epoxy resin. In a suitable embodiment, it contains only liquid epoxy resin.

[0098] The liquid epoxy resin is preferably 60% or more by mass, more preferably 80% or more by mass, further preferably 90% or more by mass, and particularly preferably 100% by mass, when the total epoxy resin is 100% by mass.

[0099] As a liquid epoxy resin, a liquid epoxy resin having two or more epoxy groups in one molecule is preferred.

[0100] The preferred liquid epoxy resins are glycyrrhizic acid type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, phenolic varnish type epoxy resin, alicyclic epoxy resin with ester skeleton, cyclohexanediol type epoxy resin, and epoxy resin with butadiene structure, with glycyrrhizic acid type epoxy resin, bisphenol A type epoxy resin, and bisphenol F type epoxy resin being more preferred.

[0101] Specific examples of liquid epoxy resins include DIC's "HP4032", "HP4032D", and "HP4032SS" (naphthalene-type epoxy resin); Mitsubishi Kemica's "828US", "jER828EL" (bisphenol A type epoxy resin), "jER807" (bisphenol F type epoxy resin), and "jER152" (phenolic varnish type epoxy resin); Mitsubishi Kemica's "630" and "630LSD"; and ADEKA's "ED-523T" (glycyrrhizin type epoxy resin) and "EP-3980S" (shrinkage-resistant epoxy resin). Glycerylamine type epoxy resin), "EP-4088S" (dicyclopentadiene type epoxy resin); "ZX1059" (a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin) manufactured by Nippon Steel Kemica & Matterol; "EX-721" (glycidyl ester type epoxy resin) manufactured by Nagasek Metex; "Cerokide 2021P" (alicyclic epoxy resin with ester skeleton) and "PB-3600" (epoxy resin with butadiene structure) manufactured by Daicel; "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane) manufactured by Nippon Steel Kemica & Matterol, etc.

[0102] As a solid epoxy resin, it is preferred to be a solid epoxy resin having three or more epoxy groups in one molecule, and more preferably an aromatic solid epoxy resin having three or more epoxy groups in one molecule.

[0103] As solid epoxy resins, the preferred types are bixylenol-type epoxy resins, naphthalene-type epoxy resins, naphthalene-type tetrafunctional epoxy resins, naphthol phenolic varnish-type epoxy resins, cresol phenolic varnish-type epoxy resins, dicyclopentadiene-type epoxy resins, triphenol-type epoxy resins, naphthol-type epoxy resins, biphenyl-type epoxy resins, naphthyl ether-type epoxy resins, anthracene-type epoxy resins, bisphenol A-type epoxy resins, bisphenol AF-type epoxy resins, phenol aralkyl-type epoxy resins, tetraphenylethane-type epoxy resins, phenol benzopyrrolidone-type epoxy resins, and phenolphthalein-type epoxy resins.

[0104] Specific examples of solid epoxy resins include DIC's "HP4032H" (naphthalene-type epoxy resin); DIC's "HP-4700" and "HP-4710" (naphthalene-type tetrafunctional epoxy resins); DIC's "N-690" (cresol phenolic varnish type epoxy resin); DIC's "N-695" (cresol phenolic varnish type epoxy resin); DIC's "HP-7200," "HP-7200HH," "HP-7200H," and "HP-7200L" (dicyclopentadiene type epoxy resin); and DIC's "EX..." A-7311, EXA-7311-G3, EXA-7311-G4, EXA-7311-G4S, HP6000 (naphthalene ether type epoxy resin); EPPN-502H (triphenol type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; NC7000L (naphthalene phenolic varnish type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; NC3000H, NC3000, NC3000L, NC3000FH, NC3100 (biphenyl type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; Nippon Steel Kemica & Materia Co., Ltd. The following epoxy resins are manufactured by Mitsubishi Kemica Co., Ltd.: "ESN475V" (naphthalene-type epoxy resin); "ESN485" (naphthalene-type epoxy resin); "ESN375" (dihydroxynaphthalene-type epoxy resin); "YX4000H", "YX4000", "YX4000HK", and "YL7890" (bi-xylenol-type epoxy resin); "YL6121" (biphenyl-type epoxy resin); "YX8800" (anthracite-type epoxy resin); Mitsubishi Kemica Co., Ltd. The following epoxy resins are used: "YX7700" (phenolic aralkyl type epoxy resin) manufactured by Karu Corporation; "PG-100" and "CG-500" manufactured by Osaka Gaskemica Corporation; "YL7760" (bisphenol AF type epoxy resin) manufactured by Mitsubishi Kemica Corporation; "YL7800" (fluorene type epoxy resin) manufactured by Mitsubishi Kemica Corporation; "jER1010" (bisphenol A type epoxy resin) manufactured by Mitsubishi Kemica Corporation; "jER1031S" (tetraphenylethane type epoxy resin) manufactured by Mitsubishi Kemica Corporation; and "WHR991S" (phenolic benzopyrrolidone type epoxy resin) manufactured by Nippon Kayaku Co., Ltd. These can be used individually or in combination of two or more.

[0105] As for (B-1) epoxy resin, when solid epoxy resin and liquid epoxy resin are used together, the mass ratio of solid epoxy resin to liquid epoxy resin (solid epoxy resin / liquid epoxy resin) is not particularly limited, but is preferably 1 or less, more preferably 0.5 or less, further preferably 0.1 or less, even more preferably 0.05 or less, and particularly preferably 0.01 or less.

[0106] (B-1) The epoxy equivalent of the epoxy resin is preferably 50 g / eq. to 5000 g / eq., more preferably 50 g / eq. to 3000 g / eq., even more preferably 80 g / eq. to 2000 g / eq., and even more preferably 110 g / eq. to 1000 g / eq. The epoxy equivalent is the mass of resin relative to one equivalent of epoxy groups. This epoxy equivalent can be determined according to JIS K7236.

[0107] (B-1) From the viewpoint of significantly achieving the desired effects of the present invention, the weight-average molecular weight (Mw) of the epoxy resin is preferably 100 to 5000, more preferably 250 to 3000, and even more preferably 400 to 1500. The weight-average molecular weight of the resin can be determined by gel permeation chromatography (GPC) using a value converted to polystyrene.

[0108] (B-1) The content (mass%) of epoxy resin is not particularly limited. From the viewpoint of achieving a more significant effect of the invention, when the non-volatile component in the resin composition is 100% by mass, it is preferably 0.1% by mass or more, more preferably 1% by mass or more, further preferably 3% by mass or more, and particularly preferably 5% by mass or more. Furthermore, from the viewpoint of achieving a more significant effect of the invention, when the non-volatile component in the resin composition is 100% by mass, it is preferably 50% by mass or less, more preferably 30% by mass or less, further preferably 20% by mass or less, and particularly preferably 10% by mass or less.

[0109] <(B-2) Epoxy Curing Accelerator>

[0110] In the case where the resin composition of the present invention comprises (B-1) epoxy resin as (B) thermosetting resin, it may further comprise (B-2) epoxy curing accelerator as an optional component. The (B-2) epoxy curing accelerator has the function of promoting the curing of (B-1) epoxy resin.

[0111] Examples of (B-2) epoxy curing accelerators include imidazole-based, phosphorus-based, urea-based, guanidine-based, metal-based, and amine-based curing accelerators. In one embodiment, the (B-2) epoxy curing accelerator preferably comprises an imidazole-based curing accelerator. One type of (B-2) epoxy curing accelerator may be used alone, or two or more may be used in combination.

[0112] Examples of imidazole-based curing accelerators include 2-methylimidazolium, 2-undecylimidazolium, 2-heptadecylimidazolium, 1,2-dimethylimidazolium, 2-ethyl-4-methylimidazolium, 1,2-dimethylimidazolium, 2-ethyl-4-methylimidazolium, 2-phenylimidazolium, 2-phenyl-4-methylimidazolium, 1-benzyl-2-methylimidazolium, 1-benzyl-2-phenylimidazolium, 1-cyanoethyl-2-methylimidazolium, 1-cyanoethyl-2-undecylimidazolium, 1-cyanoethyl-2-ethyl-4-methylimidazolium, 1-cyanoethyl-2-phenylimidazolium, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolium-(1 [1']-ethyl-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-triazine isocyanuric acid adduct, 2-phenylimidazolyl isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazolium, 2-phenyl-4-methyl-5-hydroxymethylimidazolium, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylmethylimidazolyl chloride, 2-methylimidazoline, 2-phenylimidazoline and other imidazole compounds and adducts of imidazole compounds with epoxy resins.

[0113] As imidazole-based curing accelerators, commercially available products can be used, such as "1B2PZ", "2MZA-PW", and "2PHZ-PW" manufactured by Shikoku Chemical Industry Co., Ltd., and "P200-H50" manufactured by Mitsubishi Kemikal Co., Ltd.

[0114] Examples of phosphorus-based curing accelerators include tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium acetate, tetrabutylphosphonium decanoate, tetrabutylphosphonium laurate, bis(tetrabutylphosphonium)pyromellitic phthalate, tetrabutylphosphonium hexahydrophthalate, tetrabutylphosphonium 2,6-bis[(2-hydroxy-5-methylphenyl)methyl]-4-methylphenolate, and di-tert-butylphosphonium tetraphenylborate, as well as aliphatic phosphorus salts such as methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, propyltriphenylphosphonium bromide, butyltriphenylphosphonium bromide, and benzyltriphenylphosphonium chloride. Aromatic phosphorus salts including tetraphenylphosphonium bromide, p-tolyltriphenylphosphonium tetra-p-tolylborate, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetra-p-tolylborate, triphenylethylphosphonium tetraphenylborate, tri(3-methylphenyl)ethylphosphonium tetraphenylborate, tri(2-methoxyphenyl)ethylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate, etc.; aromatic phosphine-borane complexes such as triphenylphosphine-triphenylborane; aromatic phosphine-quinone addition reactants such as triphenylphosphine-p-benzoquinone addition reactants; tributylphosphine, triterpenoid... Butylphosphine, trioctylphosphine, di-tert-butyl(2-butenyl)phosphine, di-tert-butyl(3-methyl-2-butenyl)phosphine, tricyclohexylphosphine, and other aliphatic phosphines; dibutylphenylphosphine, di-tert-butylphenylphosphine, methyldiphenylphosphine, ethyldiphenylphosphine, butyldiphenylphosphine, diphenylcyclohexylphosphine, triphenylphosphine, tri-o-tolylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine, tris(4-ethylphenyl)phosphine, tris(4-propylphenyl)phosphine, tris(4-isopropylphenyl)phosphine, tris(4-butylphenyl)phosphine, tris(4-tert-butylphenyl)phosphine, tris(2,4-dimethylphenyl)phosphine, tris(2,5-dimethylphenyl)phosphine, Tris(2,6-dimethylphenyl)phosphine, tris(3,5-dimethylphenyl)phosphine, tris(2,4,6-trimethylphenyl)phosphine, tris(2,6-dimethyl-4-ethoxyphenyl)phosphine, tris(2-methoxyphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(4-ethoxyphenyl)phosphine, tris(4-tert-butoxyphenyl)phosphine, diphenyl-2-pyridylphosphine, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,2-bis(diphenylphosphino)acetylene, 2,2'-bis(diphenylphosphino)diphenyl ether, and other aromatic phosphines.

[0115] Examples of urea-based curing accelerators include 1,1-dimethylurea; aliphatic dimethylureas such as 1,1,3-trimethylurea, 3-ethyl-1,1-dimethylurea, 3-cyclohexyl-1,1-dimethylurea, and 3-cyclooctyl-1,1-dimethylurea; and 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, and 3-(3,4-dimethylphenyl)-1,1-dimethylurea. Aromatic dimethylureas include 1-dimethylurea, 3-(4-isopropylphenyl)-1,1-dimethylurea, 3-(4-methoxyphenyl)-1,1-dimethylurea, 3-(4-nitrophenyl)-1,1-dimethylurea, 3-[4-(4-methoxyphenoxy)phenyl]-1,1-dimethylurea, 3-[4-(4-chlorophenoxy)phenyl]-1,1-dimethylurea, 3-[3-(trifluoromethyl)phenyl]-1,1-dimethylurea, N,N-(1,4-phenylene)bis(N',N'-dimethylurea), and N,N-(4-methyl-1,3-phenylene)bis(N',N'-dimethylurea)[toluenebisdimethylurea], etc.

[0116] Examples of guanidine-based curing accelerators include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1-methylbiguanidine, 1-ethylbiguanidine, 1-n-butylbiguanidine, 1-n-octadecylbiguanidine, 1,1-dimethylbiguanidine, 1,1-diethylbiguanidine, 1-cyclohexylbiguanidine, 1-allylbiguanidine, 1-phenylbiguanidine, and 1-(o-tolyl)biguanidine.

[0117] Examples of metal-based curing accelerators include 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) and cobalt(III) acetylacetone, organocopper complexes such as copper(II) acetylacetone, organozinc complexes such as zinc(II) acetylacetone, organoiron complexes such as iron(III) acetylacetone, organonickel complexes such as nickel(II) acetylacetone, and organomanganese complexes such as manganese(II) acetylacetone. Examples of organometallic salts include zinc octoate, tin octoate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

[0118] Examples of amine-based curing accelerators include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyl dimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)-undecene.

[0119] As an amine-based curing accelerator, commercially available products can be used, such as "MY-25" manufactured by Ajinomoto Finetech Co., Ltd.

[0120] (B-2) The content (mass%) of the epoxy 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 or less, further preferably 2% by mass or less, and particularly preferably 1% by mass or less. In addition, the lower limit can be, for example, 0% by mass or more, 0.01% by mass or more, 0.1% by mass or more, 0.5% by mass or more, etc.

[0121] <(B-3) Epoxy Curing Agent>

[0122] In the case where the resin composition of the present invention comprises (B-1) epoxy resin as (B) thermosetting resin, it may further comprise (B-3) epoxy curing agent as an optional component. The (B-3) epoxy curing agent has the function of reacting with (B-1) epoxy resin to cure the resin composition.

[0123] There are no particular limitations on the (B-3) epoxy curing agent, and examples include phenolic curing agents, carbodiimide curing agents, acid anhydride curing agents, amine curing agents, benzoxazine curing agents, cyanate ester curing agents, and thiol curing agents. One (B-3) epoxy curing agent can be used alone, or two or more can be used in combination. A phenolic curing agent is preferably included in the (B-3) epoxy curing agent.

[0124] There are no particular limitations on the type of phenolic curing agent, but biphenyl-type curing agents, naphthalene-type curing agents, phenolic varnish-type curing agents, naphthalene ether-type curing agents, and phenolic curing agents containing a triazine skeleton are preferred. Specifically, examples include biphenyl-type curing agents such as "MEH-7700", "MEH-7810", and "MEH-7851" (manufactured by Meiwa Kasei Corporation); naphthalene-type curing agents such as "NHN", "CBN", and "GPH" (manufactured by Nippon Kayaku Co., Ltd.); "SN170", "SN180", "SN190", "SN475", "SN485", "SN495", "SN375", and "SN395" (manufactured by Nippon Steel Chemical Co., Ltd.); "EXB9500" (manufactured by DIC Corporation); phenolic varnish-type curing agent "TD2090" (manufactured by DIC Corporation); and naphthalene ether-type curing agent "EXB-6000" (manufactured by DIC Corporation). Specific examples of phenolic curing agents containing a triazine skeleton include "LA3018", "LA7052", "LA7054", and "LA1356" (manufactured by DIC). In particular, naphthalene-type curing agents and phenolic curing agents containing a triazine skeleton are more suitable.

[0125] As a carbodiimide-based curing agent, examples include curing agents having one or more, preferably two or more, carbodiimide structures within one molecule. Examples include aliphatic bis(tert-butylcarbodiimide) and cyclohexanebis(methylene-tert-butylcarbodiimide); aromatic bis(xylylcarbodiimide); and aliphatic polycarbonyl compounds such as polyhexamethylenecarbodiimide, polytrimethylhexamethylenecarbodiimide, polycyclohexylcarbodiimide, poly(methylene biscyclohexylcarbodiimide), and poly(isofluronecarbodiimide). Diimides; poly(phenylene carbodiimide), poly(naphthylcarbodiimide), poly(tolylcarbodiimide), poly(methyldiisopropylphenylene carbodiimide), poly(triethylphenylene carbodiimide), poly(diethylphenylene carbodiimide), poly(triisopropylphenylene carbodiimide), poly(diisopropylphenylene carbodiimide), poly(xylylene carbodiimide), poly(tetramethylxylylene carbodiimide), poly(methylene diphenylene carbodiimide), poly[methylene bis(methylphenylene)carbodiimide] and other aromatic polycarbodiimides and other polycarbodiimides.

[0126] Commercially available carbodiimide-based curing agents include, for example, "Kurabo" manufactured by Nisshinbo Kamil Co., Ltd. "カイトV-02B", "カルボジライトV-03", "カルボジライトV-04K" , "Kurakuto V-07" and "Kurato V-09"; manufactured by Rakuten Co., Ltd. "スタバクゾールP", "スタバクゾールP400", "ハイカジル510", etc.

[0127] As an anhydride-based curing agent, examples include curing agents having one or more anhydride groups per molecule, preferably curing agents having two or more anhydride groups per molecule. Specific examples of anhydride-based curing agents include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride, and pyromellitic anhydride. Benzophenone tetracarboxylic dianhydride, biphenyl tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'-diphenylsulfone tetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-C]furan-1,3-dione, ethylene glycol bis(triphenylene tricarboxylic anhydride), styrene-maleic acid resin obtained by copolymerization of styrene and maleic acid, and other polymeric anhydrides. Commercially available anhydride-based curing agents include "HNA-100", "MH-700", "MTA-15", "DDSA", and "OSA" manufactured by New Japan Rika Co., Ltd.; "YH-306" and "YH-307" manufactured by Mitsubishi Kemikal Co., Ltd.; and "HN-2200" and "HN-5500" manufactured by Hitachi Chemical Co., Ltd.

[0128] As amine-based curing agents, examples include curing agents having one or more, preferably two or more, amino groups within one molecule. Examples include aliphatic amines, polyether amines, alicyclic amines, and aromatic amines. From the viewpoint of achieving the desired effect of the present invention, aromatic amines are preferred. The amine-based curing agent is preferably a primary or secondary amine, more preferably a primary amine. Specific examples of amine-based curing agents include 4,4'-methylenebis(2,6-dimethylaniline), 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, m-phenylenediamine, m-phenylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybiphenylamine, and 2,2-bis(3-amino-4-hydroxy) 2,2-bis(4-aminophenyl)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, etc. Amine-based curing agents can be commercially available, such as SEIKACURE-S manufactured by Seika Co., Ltd., KAYABOND C-200S, KAYABOND C-100, KAYABOND AA, KAYABOND AB, KAYABOND AS manufactured by Nippon Kayaku Co., Ltd., and Epicure W manufactured by Mitsubishi Kemica Co., Ltd.

[0129] Specific examples of benzoxazine-based curing agents include "JBZ-OP100D" and "ODA-BOZ" manufactured by JFE Kemica Co., Ltd.; "HFB2006M" manufactured by Showa Polymer Co., Ltd.; and "Pd" and "Fa" manufactured by Shikoku Chemical Co., Ltd.

[0130] Examples of cyanate ester curing agents include bisphenol A dicyanate, polyphenol cyanate (oligomeric (3-methylene-1,5-phenylene cyanate)), 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4'-ethoxydiphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanate phenylmethane), bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanate phenyl-1-(methylethoxy))benzene, bis(4-cyanate phenyl) sulfide and bis(4-cyanate phenyl) ether, etc., difunctional cyanate ester resins, polyfunctional cyanate ester resins derived from phenolic varnishes and cresol varnishes, etc., and prepolymers obtained by partially triazinizing these cyanate ester resins. Specific examples of cyanate ester-based curing agents include "PT30" and "PT60" (both phenolic varnish-type multifunctional cyanate ester resins) manufactured by Lonzajapan Co., Ltd., "BA230" and "BA230S75" (prepolymers obtained by partially or completely triazinizing bisphenol A dicyanate to form a trimer), etc.

[0131] Examples of thiol-based curing agents include trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetra(3-mercaptobutyrate), and tris(3-mercaptopropyl)isocyanurate.

[0132] (B-3) The reactive base equivalent of the epoxy curing agent is preferably 50 g / eq. to 3000 g / eq., more preferably 100 g / eq. to 1000 g / eq., further preferably 100 g / eq. to 500 g / eq., and particularly preferably 100 g / eq. to 300 g / eq. The reactive base equivalent is the mass of curing agent relative to 1 equivalent of reactive base.

[0133] (B-3) The content (mass%) of the epoxy curing agent is not particularly limited, but when the non-volatile component in the resin composition is 100% by mass, it is preferably 40% by mass or less, more preferably 30% by mass or less, further preferably 20% by mass or less, and particularly preferably 10% by mass or less. In addition, the lower limit can be, for example, 0% by mass or more, 0.01% by mass or more, 0.1% by mass or more, etc.

[0134] <(C) Other Additives>

[0135] The resin composition of the present invention, as a non-volatile component, may further contain optional additives. Examples of such additives include, for instance, free radical polymerizable compounds such as maleimide-based free radical polymerizable compounds, vinylphenyl-based free radical polymerizable compounds, (meth)acrylic acid-based free radical polymerizable compounds, allyl-based free radical polymerizable compounds, and polybutadiene-based free radical polymerizable compounds; free radical polymerization initiators such as peroxide-based free radical polymerization initiators and azo-based free radical polymerization initiators; thermoplastic resins such as polyvinyl acetal resin, polyolefin resin, polysulfone resin, polyethersulfone resin, polyphenylene ether resin, polycarbonate resin, polyetheretherketone resin, and polyester resin; and organic filler materials such as rubber particles. Organometallic compounds such as organocopper compounds and organozinc compounds; polymerization inhibitors such as hydroquinone, catechol, biphenyl pyrogallol, and phenothiazine; leveling agents such as silicone-based leveling agents and acrylic polymer-based leveling agents; thickeners such as modified bentonite and montmorillonite; defoamers such as silicone-based defoamers, acrylic-based defoamers, fluorinated defoamers, and vinyl resin-based defoamers; ultraviolet absorbers such as benzotriazole-based ultraviolet absorbers; adhesion enhancers such as ureasilanes; adhesion enhancers such as triazole-based, tetraazole-based, and triazine-based adhesion enhancers; antioxidants such as hindered phenol-based and hindered amine-based antioxidants. Fluorescent whitening agents such as derivatives; surfactants such as fluorinated surfactants and silicone surfactants; flame retardants such as phosphorus-based flame retardants (e.g., phosphate ester compounds, phosphazene compounds, phosphonic acid compounds, red phosphorus), nitrogen-based flame retardants (e.g., melamine sulfate), halogen-based flame retardants, and inorganic flame retardants (e.g., antimony trioxide); dispersants such as phosphate ester-based dispersants, polyoxyalkylene-based dispersants, acetylene-based dispersants, silicone-based dispersants, anionic dispersants, and cationic dispersants; stabilizers such as borate-based stabilizers, titanate-based stabilizers, aluminate-based stabilizers, zirconate-based stabilizers, isocyanate-based stabilizers, carboxylic acid-based stabilizers, and carboxylic anhydride-based stabilizers. (C) Other additives may be used alone or in combination of two or more in any ratio. (C) The content of other additives may be appropriately set by those skilled in the art.

[0136] <(D) Organic Solvents>

[0137] In addition to the aforementioned non-volatile components, the resin composition of the present invention may further contain, as a volatile component, an optional organic solvent. As the (D) organic solvent, any known organic solvent can be used as long as it can dissolve at least a portion of the non-volatile components; the type is not particularly limited. Examples of the (D) organic solvent include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, and γ-butyrolactone; ether solvents such as tetrahydropyran, tetrahydrofuran, 1,4-dioxane, diethyl ether, diisopropyl ether, dibutyl ether, and diphenyl ether; alcohol solvents such as methanol, ethanol, propanol, butanol, and ethylene glycol; and 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl diethylene glycol acetate, and γ-butyrolactone. Ether ester solvents such as methyl methoxypropionate; ester alcohol solvents such as methyl lactate, ethyl lactate, and methyl 2-hydroxyisobutyrate; ether alcohol solvents such as 2-methoxypropanol, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, and diethylene glycol monobutyl ether (butyl carbitol); amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; sulfoxide solvents such as dimethyl sulfoxide; nitrile solvents such as acetonitrile and propionitrile; aliphatic hydrocarbon solvents such as hexane, cyclopentane, cyclohexane, and methylcyclohexane; and aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and trimethylbenzene. (D) Organic solvents may be used alone or in combination of two or more in any ratio. (D) When using organic solvents, one may be used alone or in combination of two or more in any ratio. In one embodiment, (D) the lower the content of organic solvent, the better (e.g., when the non-volatile component in the resin composition is 100% by mass, it is 3% by mass or less, 1% by mass or less, 0.5% by mass or less, 0.1% by mass or less, or 0.01% by mass or less), and it is particularly preferred to have no (0% by mass).

[0138] <Characteristics of the Resin Composition>

[0139] The resin composition of the present invention comprises (A) magnetic powder and (B) thermosetting resin. The magnetic powder (A) comprises (A-1) ferrite powder with an average particle size of 0.8 μm or less and (A-2) magnetic powder with an average particle size of 1.5 μm or more. The volume ratio of the magnetic powder of component (A-2) to the ferrite powder of component (A-1) ((A-2) component / (A-1) component) is 0.8 to 34.0. By using such a resin composition, a magnetic material (cured product) with excellent mechanical strength and relative magnetic permeability can be obtained.

[0140] The cured resin composition of the present invention can have excellent relative permeability (μ'). Therefore, in one embodiment, the relative permeability (μ') of the cured resin composition measured at a measurement frequency of 100 MHz and 23°C as described in Test Example 1 below is preferably 5.0 or more, 6.0 or more, more preferably 7.0 or more, 8.0 or more, further preferably 9.0 or more, 9.5 or more, and particularly preferably 10.0 or more, 10.5 or more.

[0141] The cured resin composition of the present invention can have excellent mechanical strength. Therefore, in one embodiment, the tensile breaking strength of the cured resin composition, as measured according to JIS K7127 as in Test Example 2 below, is preferably 30 MPa or more, 35 MPa or more, more preferably 40 MPa or more, 45 MPa or more, further preferably 50 MPa or more, 55 MPa or more, and particularly preferably 60 MPa or more, 62 MPa or more.

[0142] In one embodiment, when the cured resin composition of the present invention is cut and its cross-section is observed using a scanning electron microscope (SEM), components (A-1) and (A-2) may be present in the cross-section. In another embodiment, large particles of component (A-2) appear in the cross-section of the cured composition, and the gaps between these particles are filled by the resin component (i.e., the cured component of the non-volatile components of the resin composition other than component (A)), thus including particles of component (A-1) in a dispersed manner within the resin component. In this embodiment, component (A-1) is dispersed within the resin component, therefore, compared to the case where the magnetic powder particles are simply densely packed, there is less contact between the particles of components (A-1) and (A-2). In this embodiment, a further improvement in the mechanical strength of the resin component can be achieved.

[0143] <Method for manufacturing resin composition>

[0144] The resin composition of the present invention can be manufactured, for example, by adding and mixing (A) magnetic powder, (B) thermosetting resin, (C) other additives as needed, and (D) organic solvent as needed, in any preparation container in any order and / or partially or completely simultaneously. Furthermore, during the mixing process of adding the components, the temperature can be appropriately set, and heating and / or cooling can be performed temporarily or continuously. Furthermore, stirring or agitation can be performed during the mixing process of adding the components. Furthermore, during or after the mixing process, the resin composition can be stirred or agitated using a stirring device or agitator, such as a mixer, to ensure uniform dispersion. Furthermore, degassing can be performed under low-pressure conditions such as vacuum while stirring or agitating.

[0145] [Resin Composition]

[0146] When forming a magnetically cured substrate, the resin composition can be used in the form of a paste-like resin composition at room temperature (25°C) or in the form of a resin sheet containing a layer of the resin composition.

[0147] In one embodiment, the resin composition can be prepared as a paste using an organic solvent, or it can be prepared as a paste without organic solvents using a liquid thermosetting resin such as a liquid epoxy resin. By having a low or no organic solvent content in the resin composition, the formation of voids caused by the evaporation of organic solvents can be suppressed, further improving processability and workability.

[0148] In one embodiment, the resin composition is suitable for use as a resin composition for filling through-holes. Furthermore, in one embodiment, the resin composition is suitable for use as a resin composition for forming inductor base elements for manufacturing inductor elements.

[0149] [Resin Sheets]

[0150] The resin sheet includes a support and a resin composition layer formed of the resin composition of the present invention disposed on the support.

[0151] From the viewpoint of achieving a thinner profile, the thickness of the resin composition layer is preferably 250 μm or less, more preferably 200 μm or less. There is no particular limitation on the lower limit of the resin composition layer thickness; it can typically be set to 5 μm or more, 10 μm or more, etc.

[0152] Examples of supports include films containing plastic materials, metal foils, and release paper, with films and metal foils containing plastic materials being preferred.

[0153] When a film containing a plastic material is used as the support, examples of plastic materials include polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate (hereinafter sometimes abbreviated as "PEN"), acrylic polymers such as polycarbonate (hereinafter sometimes abbreviated as "PC") and polymethyl methacrylate (PMMA), cyclic polyolefins, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, and polyimide. Among these, polyethylene terephthalate and polyethylene naphthalate are preferred, and inexpensive polyethylene terephthalate is particularly preferred.

[0154] When a metal foil is used as a support, examples of metal foils include copper foil and aluminum foil, with copper foil being preferred. As copper foil, foils containing a single metal such as copper can be used, or foils containing alloys of copper with other metals (such as tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.) can be used.

[0155] The support can be matte-finished or corona-treated on the surface that bonds to the resin composition layer.

[0156] Furthermore, as a support, a support with a release layer that has a release layer on the surface bonded to the resin composition layer can be used. Examples of release agents used in the release layer of the support with a release layer include, for example, one or more release agents selected from alkyd-based release agents, polyolefin-based release agents, polyurethane-based release agents, and silicone-based release agents. Commercially available products can be used as supports with release layers, such as LINTEC's "PET501010," "SK-1," "AL-5," and "AL-7," which are PET films having a release layer with a silicone-based or alkyd resin-based release agent as the main component; Toray's "Lumira T60"; Teijin's "Purex"; and Unipul's "Unipul," etc.

[0157] The thickness of the support is not particularly limited, but is preferably in the range of 5μm to 75μm, and more preferably in the range of 10μm to 60μm. It should be noted that when using a support with a release layer, the overall thickness of the support with the release layer is preferably within the above-mentioned range.

[0158] In resin sheets, a protective film, based on the support, can be further laminated on the side of the resin composition layer that is not bonded to the support (i.e., the side opposite to the support). The thickness of the protective film is not particularly limited, but can be, for example, 1 μm to 40 μm. By laminating the protective film, the adhesion of dirt and scratches to the surface of the resin composition layer can be suppressed. The resin sheet can be rolled up for storage. When the resin sheet has a protective film, it can be used by peeling off the protective film.

[0159] Resin sheets can be manufactured by, for example, coating a resin composition onto a support using a die coater to form a resin composition layer. If necessary, an organic solvent can be mixed into the resin composition before coating onto the support. If an organic solvent is used, drying can be performed after coating, if required.

[0160] Drying can be carried out by methods such as heating or blowing hot air. There are no particular limitations on the drying conditions; drying is carried out in a manner that ensures the organic solvent content in the resin composition layer is 10% by mass or less, preferably 5% by mass or less. Depending on the components contained in the resin composition, the resin composition layer can be formed by drying at 50°C to 150°C for 3 to 10 minutes.

[0161] The resin sheet can be rolled up for storage. If the resin sheet has a protective film, it can be used by peeling off the protective film.

[0162] [Circuit substrate and its manufacturing method]

[0163] The circuit board of the present invention comprises a cured resin composition. The circuit board of the first embodiment comprises: a substrate having through holes, and a cured resin composition of the present invention filling the aforementioned through holes. Furthermore, the circuit board of the second embodiment comprises a cured layer formed from a cured resin composition layer of a resin sheet. Hereinafter, the first and second embodiments of the circuit board manufacturing method will be described. However, the manufacturing method of the circuit board according to the present invention is not limited to the first and second embodiments illustrated below.

[0164] <First Embodiment>

[0165] The circuit board of the first embodiment is manufactured by a manufacturing method including, for example, the steps (1) to (5) described below. In the first embodiment, it is preferable to use a resin composition to form a cured product, and more preferably to use a paste-like resin composition to form a cured product.

[0166] (1) The step of filling a resin composition into a through hole of a substrate having a through hole;

[0167] (2) The step of heat curing the resin composition to obtain a cured product;

[0168] (3) Step of grinding the surface of the cured product or resin composition

[0169] (4) The step of roughening the cured material; and

[0170] (5) The step of forming a conductor layer on the surface of the cured material after roughening treatment.

[0171] The method for manufacturing the circuit board of the present invention can be carried out in the order of steps (1) to (5), or step (2) can be carried out after step (3).

[0172] <Step (1)>

[0173] Step (1) may include the step of preparing a resin composition. The resin composition is as described above.

[0174] In addition, when performing step (1), such as Figure 1 As illustrated in the example, the process may include preparing a core substrate 10, which has a support substrate 11 and a first metal layer 12 and a second metal layer 13, such as copper foil, disposed on two surfaces of the support substrate 11. Examples of materials for the support substrate 11 include insulating substrates such as glass epoxy boards, 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-bearing copper foil and materials for the conductor layers described later.

[0175] In addition, such as Figure 2 As illustrated in one example, the process may include forming a through-hole 14 in the core substrate 10. The through-hole 14 can be formed by, for example, drilling, laser irradiation, plasma irradiation, etc. Specifically, a through-hole can be formed in the core substrate 10 using a drill bit or the like, thereby forming the through-hole 14.

[0176] The through hole 14 can be formed using a commercially available drill bit device. Examples of commercially available drill bit devices include, for example, the "ND-1S211" manufactured by Hitachi Visual Communication Systems Co., Ltd.

[0177] After forming through holes 14 in the core substrate 10, as Figure 3 As shown in one example, the process may include roughening the core substrate 10 and forming a plating layer 20 in the through hole 14, on the surface of the first metal layer 12, and on the surface of the second metal layer 13.

[0178] As described above, roughening treatment can be performed using either dry or wet methods. Examples of dry roughening treatment include plasma treatment. Furthermore, examples of wet roughening treatment include methods that sequentially perform swelling treatment using a swelling solution, roughening treatment using an oxidizing agent, and neutralization treatment using a neutralizing solution.

[0179] The plating layer 20 is formed by plating, and the process of forming the plating layer 20 by plating is the same as the formation of the conductor layer in step (5) described later.

[0180] After preparing the core substrate 10, as follows Figure 4 As shown in the example, the through-hole 14 is filled with resin composition 30a. The filling can be performed, for example, by printing. Examples of printing methods include printing resin composition 30a into the through-hole 14 via a squeegee, printing resin composition 30a via an ink cartridge, printing resin composition 30a by mask printing, roller coating, inkjet printing, etc.

[0181] <Step (2)>

[0182] In step (2), after filling the through hole 14 with resin composition 30a, the resin composition 30a is thermo-cured, such as... Figure 5 As shown in the example, a cured product 30 is formed within the through-hole 14. The thermosetting conditions of the resin composition 30a vary depending on the composition and type of the resin composition 30a. The curing temperature is preferably 120°C or higher, more preferably 130°C or higher, even more preferably 150°C or higher, preferably 245°C or lower, more preferably 220°C or lower, and even more preferably 200°C or lower. The curing time of the resin composition 30a is preferably 5 minutes or higher, more preferably 10 minutes or higher, even more preferably 15 minutes or higher, preferably 120 minutes or lower, more preferably 110 minutes or lower, and even more preferably 100 minutes or lower.

[0183] The degree of curing of the cured product 30 in step (2) is preferably 80% or more, more preferably 85% or more, and even more preferably 90% or more. The degree of curing can be measured using, for example, a differential scanning calorimeter.

[0184] Before heat curing the resin composition 30a, a preheating treatment can be performed on the resin composition 30a at a temperature lower than the curing temperature. For example, before heat curing the resin composition 30a, the resin composition 30a can be preheated for 5 minutes or more (preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes) at a temperature of 50°C or higher and lower than 120°C (preferably 60°C or higher and lower than 110°C, more preferably 70°C or higher and lower than 100°C).

[0185] <Step (3)>

[0186] In step (3), such as Figure 6 As shown in the example, planarization is achieved by removing the remaining cured material 30 protruding from or attached to the core substrate 10 through grinding. As a grinding method, a method capable of grinding the remaining cured material 30 protruding from or attached to the core substrate 10 can be used. Examples of such grinding methods include, for example, leather abrasive polishing and belt polishing. Commercially available leather abrasive polishing equipment includes, for example, the "NT-700IM" manufactured by Ishii Optoelectronics Co., Ltd.

[0187] The arithmetic mean roughness (Ra) of the polished surface of the cured material 30 (after thermal curing of the cured layer) is preferably 300 nm or more, more preferably 350 nm or more, and even more preferably 400 nm or more, from the viewpoint of improving adhesion to the coating layer. The upper limit is preferably 1000 nm or less, more preferably 900 nm or less, and even more preferably 800 nm or less. The surface roughness (Ra) can be measured, for example, using a non-contact surface roughness meter.

[0188] When step (3) is performed after step (2), heat treatment may be performed as needed after step (2) and before step (3) to further improve the curing degree of the cured material 30. The temperature in the aforementioned heat treatment may be the curing temperature described above, preferably 120°C or higher, more preferably 130°C or higher, more preferably 150°C or higher, preferably 245°C or lower, more preferably 220°C or lower, and more preferably 200°C or lower. The heat treatment time is preferably 5 minutes or more, more preferably 10 minutes or more, more preferably 15 minutes or more, preferably 90 minutes or less, more preferably 70 minutes or less, and more preferably 60 minutes or less.

[0189] Furthermore, if step (3) is performed before step (2), a preheating treatment at a temperature lower than the curing temperature of the resin composition can be performed before step (3). The temperature in the aforementioned preheating treatment is preferably 100°C or higher, more preferably 110°C or higher, even more preferably 120°C or higher, preferably 245°C or lower, more preferably 220°C or lower, and even more preferably 200°C or lower. The heat treatment time is preferably 5 minutes or more, more preferably 10 minutes or more, even more preferably 15 minutes or more, preferably 90 minutes or less, more preferably 70 minutes or less, and even more preferably 60 minutes or less.

[0190] <Step (4)>

[0191] In step (4), the surface that was ground in step (3) is roughened (de-smudge treatment). The process and conditions for the roughening step are not particularly limited, and well-known processes and conditions commonly used in the manufacturing methods of multilayer printed circuit boards can be adopted. As a roughening step, the cured material 30 can be roughened, for example, by performing swelling treatment using a swelling liquid, roughening treatment using an oxidizing agent, and neutralization treatment using a neutralizing liquid in sequence.

[0192] There are no particular limitations on the swelling liquid that can be used in the roughening step; examples include alkaline solutions and surfactant solutions, with alkaline solutions being preferred. Among the alkaline solutions used as swelling liquids, sodium hydroxide solutions and potassium hydroxide solutions are more preferred. Commercially available swelling liquids include, for example, "Swelling Disc Securitization P" and "Swelling Disc Securitization SBU" manufactured by Atotech Japan.

[0193] There are no particular limitations on the swelling treatment using a swelling liquid. For example, it can be performed by immersing the core substrate 20, on which the cured material 30 is disposed, in a swelling liquid at a temperature of 30°C to 90°C for 1 minute to 20 minutes. From the viewpoint of suppressing the swelling of the resin constituting the cured material 30 to an appropriate level, it is preferable to immerse the cured material 30 in a swelling liquid at a temperature of 40°C to 80°C for 5 minutes to 15 minutes.

[0194] The oxidizing agent that can be used in the roughening treatment using an oxidizing agent is not particularly limited, and examples include, for instance, an alkaline permanganate solution obtained by dissolving potassium permanganate or sodium permanganate in an aqueous solution of sodium hydroxide. The roughening treatment using an oxidizing agent such as an alkaline permanganate solution is preferably performed by immersing the solidified material 30 in an oxidizing agent solution heated to 60°C to 80°C for 10 to 30 minutes. Furthermore, the concentration of permanganate in the alkaline permanganate solution is preferably set to 5% to 10% by mass. Commercially available oxidizing agents include, for example, alkaline permanganate solutions such as "Concentrate Compact P" and "Dozing Solution Securigans P" manufactured by Atotech Japan.

[0195] The neutralizing solution that can be used in the neutralization process is preferably an acidic aqueous solution. Commercially available examples include, for instance, "Reduction Solution Sequencing P" manufactured by Atotech Japan. The neutralization process using the neutralizing solution can be performed by immersing the surface roughened with the oxidizing agent solution in a neutralizing solution at 30°C to 80°C for 5 to 30 minutes. From a workability perspective, it is preferable to immerse the cured material 30, which has been roughened with the oxidizing agent solution, in a neutralizing solution at 40°C to 70°C for 5 to 20 minutes.

[0196] The arithmetic mean roughness (Ra) of the cured material 30 after roughening treatment is preferably 300 nm or more, more preferably 350 nm or more, and even more preferably 400 nm or more, from the viewpoint of improving adhesion to the coating layer. The upper limit is preferably 1500 nm or less, more preferably 1200 nm or less, and even more preferably 1000 nm or less. The surface roughness (Ra) can be measured using, for example, a non-contact surface roughness meter.

[0197] <Step (5)>

[0198] In step (5), such as Figure 7 As shown in the example, a conductor layer 40 is formed on the polished surface of the cured material 30 and the core substrate. Furthermore, after forming the conductor layer 40, as... Figure 8As shown in the example, a portion of the conductor layer 40, the first metal layer 12, the second metal layer 13, and the plating layer 20 can be removed by processes such as etching to form a patterned conductor layer 41. Figure 7 In this process, the conductor layer 40 is formed on both sides of the core substrate 10, but the conductor layer 40 may also be formed on only one side of the core substrate 10.

[0199] Methods for forming the conductor layer 40 include, for example, plating, sputtering, and vapor deposition, with plating being preferred. In suitable embodiments, a patterned conductor layer 41 with a desired wiring pattern is formed by plating on the surface of the cured material 30 (and the plating layer 20) using appropriate methods such as semi-additive or fully additive methods. 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; and alloys of two or more metals selected from gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. From the viewpoints of versatility, cost, and ease of pattern formation, chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or nickel-chromium alloys, copper-nickel alloys, or copper-titanium alloys, are preferred; chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or nickel-chromium alloys, are more preferred; and copper is even more preferred.

[0200] Here, an example of an embodiment in which a patterned conductor layer 41 is formed on a surface of the cured material 30 that has been polished is described in detail. A plating seed layer is formed on the polished surface of the cured material 30 by electroless plating. Next, an electroplated layer is formed on the formed plating seed layer by electroplating. If necessary, unwanted plating seed layers are removed by etching or other processes, and a conductor layer 40 with the desired wiring pattern can be formed. After the conductor layer 40 is formed, annealing can be performed as needed to improve the peel strength of the conductor layer 40, etc. Annealing can be performed, for example, by heating the circuit board at 150-200°C for 20-90 minutes.

[0201] From the viewpoint of achieving a thinner profile, the thickness of the patterned conductor layer is preferably 70 μm or less, more preferably 60 μm or less, further preferably 50 μm or less, even more preferably 40 μm or less, particularly preferably 30 μm or less, 20 μm or less, 15 μm or less, or 10 μm or less. The lower limit is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more.

[0202] <Second Implementation>

[0203] The circuit board of the second embodiment includes a cured layer formed from a cured resin composition. In the second embodiment, it is preferable to use a resin sheet to form the cured layer. Hereinafter, a second embodiment of the method for manufacturing the product substrate will be described. Descriptions that overlap with those of the first embodiment will be omitted as appropriate.

[0204] The circuit board of the second embodiment is manufactured by a manufacturing method including, for example, the steps (A) to (D) described below.

[0205] (A) The step of laminating a resin sheet onto an inner substrate in such a way as to bond a resin composition layer to an inner substrate to form a cured layer.

[0206] (B) Step of creating pores in the cured layer;

[0207] (C) The step of roughening the surface of the cured layer; and

[0208] (D) The step of forming a conductor layer on the polished surface of the cured layer.

[0209] The following is a detailed explanation of steps (A) to (D) described above when manufacturing a circuit board.

[0210] <Step (A)>

[0211] Step (A) is a step of laminating a resin sheet onto an inner substrate in such a way that the resin composition layer is bonded to the inner substrate to form a cured layer. As one embodiment of step (A), the resin sheet is laminated onto the inner substrate in such a way that the resin composition layer is bonded to the inner substrate, and the resin composition layer is thermally cured to form a cured layer.

[0212] In step (A), such as Figure 9 As shown in the example, a resin sheet 310, which includes a support 330 and a resin composition layer 320a disposed on the support 330, is laminated on the inner layer substrate 200 in such a way that the resin composition layer 320a is bonded to the inner layer substrate 200.

[0213] 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 boards, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates. The inner layer substrate 200 can be an inner circuit substrate with wiring embedded within its thickness.

[0214] like Figure 9As shown in the example, the inner substrate 200 has a first conductor layer 420 disposed on a first main surface 200a and an external terminal 240 disposed on a second main surface 200b. The first conductor layer 420 may include multiple wirings. In the example, only the wiring of the coil-shaped conductive structure 400 constituting the inductor element is shown. The external terminal 240 is a terminal for electrical connection to an external device, etc., not shown. The external terminal 240 may be configured as part of the conductor layer disposed on the second main surface 200b.

[0215] 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)>” column of the first embodiment.

[0216] The first conductor layer 420 and the external terminal 240 can be a single-layer structure, or a multi-layer structure obtained by stacking two or more single metal layers or alloy layers containing different kinds of metals or alloys. In addition, the thickness of the first conductor layer 420 and the external terminal 240 is the same as that of the second conductor layer 440 described later.

[0217] The line (L) / spacing (S) ratio of the first conductor layer 420 and the external terminal 240 is not particularly limited. From the viewpoint of reducing surface unevenness to obtain a cured layer with excellent smoothness, it is generally 900 / 900 μm or less, preferably 700 / 700 μm or less, more preferably 500 / 500 μm or less, further preferably 300 / 300 μm or less, and even more preferably 200 / 200 μm or less. The lower limit of the line / spacing ratio is not particularly limited. From the viewpoint of achieving good embedding of the resin composition layer in the spacing, it is preferably 1 / 1 μm or more.

[0218] The inner layer substrate 200 may have a plurality of through holes 220 extending through the inner layer substrate 200 from the first main surface 200a to the second main surface 200b. Through-hole wiring 220a is provided in the through holes 220. Through-hole wiring 220a electrically connects the first conductor layer 420 to the external terminal 240.

[0219] The bonding between the resin composition layer 320a and the inner substrate 200 can be achieved, for example, by heating and pressing the resin sheet 310 to the inner substrate 200 from the support 330 side. Examples of components for heating and pressing the resin sheet 310 to the inner substrate 200 (hereinafter also referred to as "heat-pressing components") include, for example, heated metal plates (stainless steel (SUS) mirror plates, etc.) or metal rollers (SUS rollers). It should be noted that the pressure is not applied by direct contact between the heat-pressing component and the resin sheet 310; rather, it is preferable to apply pressure via a sheet containing an elastic material such as heat-resistant rubber, in a manner that the resin sheet 310 fully follows the surface irregularities of the inner substrate 200.

[0220] The temperature during heat pressing is preferably in the range of 80℃~160℃, more preferably 90℃~140℃, and even more preferably 100℃~120℃. The pressure during heat pressing is preferably in the range of 0.098MPa~1.77MPa, more preferably 0.29MPa~1.47MPa. The time during heat pressing is preferably in the range of 20 seconds~400 seconds, more preferably 30 seconds~300 seconds. The bonding of the resin sheet to the inner substrate is preferably carried out under reduced pressure conditions of 26.7 hPa or less.

[0221] The bonding of the resin composition layer 320a of the resin sheet 310 to the inner substrate 200 can be performed using a commercially available vacuum laminator. Examples of commercially available vacuum laminators include, for instance, the vacuum pressure laminator manufactured by Meiki Manufacturing Co., Ltd., and the vacuum applicator manufactured by Niko Materias Co., Ltd.

[0222] After the resin sheet 310 is bonded to the inner substrate 200, the laminated resin sheet 310 can be smoothed by applying pressure from the support 330 side under normal pressure (atmospheric pressure), for example, by applying pressure from the support 330 side using a heated pressing member. The pressure conditions for the smoothing process can be set to the same conditions as the heated pressing conditions for the lamination described above. The smoothing process can be performed using a commercially available laminator. It should be noted that lamination and smoothing processes can be performed continuously using the aforementioned commercially available vacuum laminator.

[0223] After the resin sheet 310 is laminated onto the inner substrate 200, the resin composition layer 320a is thermosetting to form a cured layer. For example... Figure 10 As shown in one example, the resin composition layer 320a bonded to the inner substrate 200 is thermally cured to form the first cured layer 320.

[0224] The thermosetting conditions of the resin composition layer 320a vary depending on the composition and type of the resin composition. The curing temperature is preferably 120°C or higher, more preferably 130°C or higher, even more preferably 150°C or higher, preferably 245°C or lower, more preferably 220°C or lower, and even 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, even more preferably 15 minutes or more, preferably 120 minutes or less, more preferably 110 minutes or less, and even more preferably 100 minutes or less.

[0225] The support 330 can be removed between step (B) and after the thermosetting in step (A), or it can be peeled off after step (B).

[0226] The arithmetic mean roughness (Ra) of the cured layer before roughening treatment is preferably 300 nm or more, more preferably 350 nm or more, and even more preferably 400 nm or more, from the viewpoint of improving adhesion to the coating layer. The upper limit is preferably 1000 nm or less, more preferably 900 nm or less, and even more preferably 800 nm or less. The surface roughness (Ra) can be measured, for example, using a non-contact surface roughness meter.

[0227] Step (A) can replace the resin sheet by applying the resin composition onto the inner substrate 200 using a die coating machine or the like, and then curing it to form a cured layer.

[0228] <Step (B)>

[0229] In step (B), such as Figure 11 As shown in the example, an opening is formed in the first cured layer 320 to create a via 360. The via 360 is a passage for electrically connecting the first conductor layer 420 to the second conductor layer 440, which will be described later. The formation of the via 360 can be carried out using, for example, a drill bit, a laser, or plasma, depending on the composition of the resin composition used in the formation of the cured layer. The size and shape of the hole can be appropriately determined according to the design of the printed circuit board.

[0230] <Step (C)>

[0231] In step (C), the surface of the cured layer in which the via is formed is roughened. As described in the “<Step (4)>” section of the first embodiment, the roughening process in step (C) is as follows.

[0232] The arithmetic mean roughness (Ra) of the cured layer after roughening treatment is preferably 300 nm or more, more preferably 350 nm or more, and even more preferably 400 nm or more, from the viewpoint of improving adhesion to the coating layer. The upper limit is preferably 1500 nm or less, more preferably 1200 nm or less, and even more preferably 1000 nm or less. The surface roughness (Ra) can be measured using, for example, a non-contact surface roughness meter.

[0233] <Step (D)>

[0234] In step (D), such as Figure 12 As shown in the example, a second conductor layer 440 is formed on the first cured layer 320.

[0235] The conductor material that can form the second conductor layer 440 is the same as the material of the conductor layer described in the “<Step (5)>” column of the first embodiment.

[0236] From the viewpoint of thinning, 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, particularly preferably 30 μm or less, 20 μm or less, 15 μm or less, or 10 μm or less. The lower limit is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more.

[0237] 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 or fully additive method, including an electroless plating step, a mask patterning step, an electrolytic plating step, and a rapid etching step. By forming the second conductor layer 440 using a wet plating method, it can be formed as a second conductor layer 440 containing the desired wiring pattern. It should be noted that, through this step, the via wiring 360a is also formed within the via 360.

[0238] The first conductor layer 420 and the second conductor layer 440 are, for example, as described later. Figures 13-15 As shown in the example, it can be configured in a spiral shape. In one example, one end of the spiral-shaped wiring portion of the second conductor layer 440 is electrically connected to one end of the spiral-shaped wiring portion of the first conductor layer 420 via the through-hole wiring 360a. The other end of the spiral-shaped wiring portion of the second conductor layer 440 is electrically connected to the ground (land) 420a of the first conductor layer 42 via the through-hole wiring 360a. Therefore, the other end of the spiral-shaped wiring portion of the second conductor layer 440 is electrically connected to the external terminal 240 via the through-hole wiring 360a, the ground 420a, and the through-hole wiring 220a.

[0239] The coil-shaped conductive structure 400 is composed of a spiral-shaped wiring portion that is part of the first conductor layer 420, a spiral-shaped wiring portion that is part of the second conductor layer 440, and a through-hole wiring 360a that electrically connects the spiral-shaped wiring portions of the first conductor layer 420 and the spiral-shaped wiring portions of the second conductor layer 440.

[0240] Following step (D), a further step of forming a cured layer on the conductor layer can be performed. Specifically, as follows... Figure 14 As shown in the example, a second cured layer 340 is formed on the second conductor layer 440 and the first cured layer 320 on which the via wiring 360a is formed. The second cured layer can be formed by the same steps as those already described.

[0241] [Inductor substrate]

[0242] The inductor substrate includes the circuit substrate of the present invention. When such an inductor substrate includes a circuit substrate obtained by the manufacturing method of the circuit substrate of the first embodiment, it has an inductor pattern formed of conductors on at least a portion of the cured resin composition. Such an inductor substrate can utilize, for example, the substrate described in Japanese Patent Application Publication No. 2016-197624.

[0243] Furthermore, in the case of a circuit board obtained by the manufacturing method of the circuit board of the second embodiment, the inductor board has a cured layer and a conductive structure embedded in the cured layer, and includes an inductor element composed of the conductive structure and a portion of the cured layer extending in the thickness direction of the cured layer and surrounded by the conductive structure. Here, Figure 13 This is a planar schematic diagram of an inductor substrate containing inductor elements, viewed only from one of its thickness directions. Figure 14 It is shown in Figure 13 A schematic diagram of the cut end face of the inductor substrate, shown at the location indicated by the dashed line II-II. Figure 15 This is a planar schematic diagram used to illustrate the structure of the first conductor layer in an inductor substrate.

[0244] Circuit board 100 Figure 13 and Figure 14 As shown as an example, it is a multilayer wiring board having multiple cured layers (first cured layer 320, second cured layer 340) and multiple conductor layers (first conductor layer 420, second conductor layer 440), that is, a multilayer wiring board having built-up cured layers and multilayer conductor layers. In addition, the inductor substrate 100 has an inner layer substrate 200.

[0245] according to Figure 14 The first cured layer 320 and the second cured layer 340 constitute a magnetic portion 300 of the cured layer that can be considered as a single unit. Therefore, the coil-shaped conductive structure 400 is provided such that at least a portion of it is embedded in the magnetic portion 300. That is, in the inductor substrate 100 of this embodiment, the inductor element is composed of the coil-shaped conductive structure 400 and a portion of the magnetic portion 300, namely the core, that extends in the thickness direction of the magnetic portion 300 and is surrounded by the coil-shaped conductive structure 400.

[0246] like Figure 15As illustrated in the figure, the first conductor layer 420 includes a spiral-shaped wiring portion for forming a coil-shaped conductive structure 400, and a rectangular grounding 420a electrically connected to the wiring 220a within the through-hole. In the example, the spiral-shaped wiring portion includes a straight portion, a bent portion that curves at right angles, and a detour portion that meanders at the grounding 420a. In the example, the spiral-shaped wiring portion of the first conductor layer 420 has an overall approximately rectangular outline and a shape that winds counterclockwise from the center outwards.

[0247] Similarly, a second conductor layer 440 is provided on the first cured layer 320. The second conductor layer 440 includes a spiral wiring portion for forming a coil-shaped conductive structure 400. Figure 13 or Figure 14 In the middle, the vortex-shaped wiring section includes a straight section and a curved section bent at right angles. Figure 13 or Figure 14 In the middle, the spiral wiring portion of the second conductor layer 44 has an overall outline that is approximately rectangular and is wound clockwise from the center to the outside.

[0248] 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 in which the wiring board is used as an inner layer substrate. Furthermore, it can be used as a chip inductor component with the wiring board monolithically mounted, and can also be used as a printed wiring board for surface mounting the chip inductor component.

[0249] Furthermore, various types of semiconductor devices can be manufactured using the aforementioned wiring board. Semiconductor devices incorporating the aforementioned wiring board are suitable for use in electrical products (e.g., computers, mobile phones, digital cameras, and televisions) and vehicles (e.g., autonomous two-wheeled vehicles, automobiles, trains, ships, and aircraft). Example

[0250] The present invention will now be specifically described through examples. The present invention is not limited to these examples. It should be noted that, unless otherwise specified, the "%" indicating quantity refers to "mass %". Furthermore, unless otherwise specified, the temperature condition is room temperature (23°C).

[0251] <Example 1>

[0252] The following mixture was prepared by adding 30 parts by weight of nano-soft magnetic powder a ("M001" manufactured by Powdertech Co., Ltd., Mn-based ferrite, average particle size 0.15 μm) and 70 parts by weight of micron-sized soft magnetic powder a ("AW08PF3F" manufactured by Epsilon Micix Co., Ltd., FeSiCr-based alloy (amorphous), average particle size 3 μm), liquid epoxy resin a ("ZX-1059" manufactured by Nippon Steel Kemical & Materia Co., Ltd.), bisphenol A type epoxy resin and bisphenol F type epoxy resin. The following components were prepared by uniformly dispersing the following resin composition: 3 parts by weight of a mixture of the following: liquid epoxy resin b ("EP-4088S" manufactured by ADEKA, a glycidyl ether type aliphatic epoxy), 1 part by weight of liquid epoxy resin c ("630" manufactured by Mitsubishi Kemikal, a glycidyl ether type aromatic epoxy), and 1 part by weight of epoxy curing accelerator ("2MZA-PW" manufactured by Shikoku Kasei, an imidazole-based curing accelerator).

[0253] <Example 2>

[0254] The resin composition was prepared in the same manner as in Example 1, except that 70 parts by weight of micron-sized soft magnetic powder b (manufactured by DOWA Electric Co., Ltd., Fe-50%Ni alloy, average particle size 3 μm) was used to replace 70 parts by weight of micron-sized soft magnetic powder a (manufactured by Epsilon Mix Co., Ltd., "AW08PF3F").

[0255] <Example 3>

[0256] The resin composition was prepared in the same manner as in Example 1, except that 70 parts by weight of micron-sized soft magnetic powder c (MZ05 manufactured by Powdertech Co., Ltd., MnZn-based ferrite with an average particle size of 3 μm) was used to replace 70 parts by weight of micron-sized soft magnetic powder a (AW08PF3F manufactured by Epsilon Tomic Co., Ltd.).

[0257] <Example 4>

[0258] The amount of nano-soft magnetic powder a (manufactured by Powdertech Co., Ltd., "M001") used was changed from 30 parts by weight to 5 parts by weight, and the amount of micron-soft magnetic powder a (manufactured by Episonic Co., Ltd., "AW08PF3F") used was changed from 70 parts by weight to 95 parts by weight. Otherwise, the resin composition was prepared in the same manner as in Example 1.

[0259] <Example 5>

[0260] The amount of nano-soft magnetic powder a (manufactured by Powdertech Co., Ltd., "M001") used was changed from 30 parts by mass to 40 parts by mass, and the amount of micron-soft magnetic powder a (manufactured by Episonic Co., Ltd., "AW08PF3F") used was changed from 70 parts by mass to 60 parts by mass. Otherwise, the resin composition was prepared in the same manner as in Example 1.

[0261] <Example 6>

[0262] The resin composition was prepared in the same manner as in Example 1, except that 30 parts by weight of nano-soft magnetic powder b (MZ001 manufactured by Powdertech Co., Ltd., MnZn ferrite, average particle size 0.15 μm) was used to replace 30 parts by weight of nano-soft magnetic powder a (M001 manufactured by Powdertech Co., Ltd.).

[0263] <Example 7>

[0264] The resin composition was prepared in the same manner as in Example 1, except that 30 parts by weight of nano-soft magnetic powder c ("NZ001" manufactured by Powdertech Co., Ltd., NiZn ferrite, average particle size 0.15 μm) was used to replace 30 parts by weight of nano-soft magnetic powder a ("M001" manufactured by Powdertech Co., Ltd.).

[0265] <Example 8>

[0266] The resin composition was prepared in the same manner as in Example 1, except that 30 parts by weight of nano-soft magnetic powder d (manufactured by Powdertech Co., Ltd., “E001”, MnMgSr ferrite, average particle size 0.15 μm) was used to replace 30 parts by weight of nano-soft magnetic powder a (manufactured by Powdertech Co., Ltd., “M001”).

[0267] <Comparative Example 1>

[0268] The amount of nano-soft magnetic powder a (manufactured by Powdertech Co., Ltd., "M001") used was changed from 70 parts by weight to 100 parts by weight, but the resin composition was prepared in the same manner as in Example 1.

[0269] <Comparative Example 2>

[0270] Instead of using nano-soft magnetic powder a (manufactured by Powdertech Co., Ltd., "M001"), 100 parts by weight of micron-soft magnetic powder b (manufactured by DOWA Electronics Co., Ltd., Fe-50%Ni alloy, average particle size 3μm) were used to replace 70 parts by weight of micron-soft magnetic powder a (manufactured by Electronics Co., Ltd., "AW08PF3F"), and the resin composition was prepared in the same manner as in Example 1.

[0271] <Comparative Example 3>

[0272] The resin composition was prepared in the same manner as in Example 1, except that 100 parts by weight of micron-sized soft magnetic powder c (MZ05) was used instead of nano-sized soft magnetic powder a (M001 manufactured by Powdertech Co., Ltd.) to replace 70 parts by weight of micron-sized soft magnetic powder a (AW08PF3F manufactured by Epsilon Tomics Co., Ltd.).

[0273] <Comparative Example 4>

[0274] The amount of nano-soft magnetic powder a (manufactured by Powdertech Co., Ltd., "M001") was changed from 30 parts by mass to 2 parts by mass, and the amount of micron-soft magnetic powder a (manufactured by Episonic Co., Ltd., "AW08PF3F") was changed from 70 parts by mass to 98 parts by mass. Otherwise, the resin composition was prepared in the same manner as in Example 1.

[0275] <Comparative Example 5>

[0276] The amount of nano-soft magnetic powder a (manufactured by Powdertech Co., Ltd., "M001") used was changed from 30 parts by mass to 50 parts by mass, and the amount of micron-soft magnetic powder a (manufactured by Episonic Co., Ltd., "AW08PF3F") used was changed from 70 parts by mass to 50 parts by mass. Otherwise, the resin composition was prepared in the same manner as in Example 1.

[0277] <Comparative Example 6>

[0278] The resin composition was prepared in the same manner as in Example 1, except that 30 parts by weight of other soft magnetic powder a ("AW08PF1F" manufactured by Epson Magnetics Co., Ltd., FeSi alloy, average particle size 1 μm) was used to replace 30 parts by weight of nano soft magnetic powder a ("M001" manufactured by Powdertech Co., Ltd.).

[0279] <Comparative Example 7>

[0280] The resin composition was prepared in the same manner as in Example 1, except that 70 parts by weight of micron-sized soft magnetic powder c (MZ05 manufactured by Powdertech Co., Ltd., MnZn-based ferrite, average particle size 3 μm) was used instead of micron-sized soft magnetic powder a (AW08PF3F manufactured by Epsilon Micix Co., Ltd.), and 30 parts by weight of other soft magnetic powder b (MZ03S manufactured by Powdertech Co., Ltd., MnZn-based ferrite, average particle size 1 μm) was used instead of nano-sized soft magnetic powder a (M001 manufactured by Powdertech Co., Ltd.).

[0281] <Experimental Example 1: Determination of Relative Permeability>

[0282] As a support, a polyethylene terephthalate (PET) film (LINTEC "PET501010", 50 μm thick) treated with a silicone-based release agent was prepared. The resin composition obtained in the examples and comparative examples was uniformly coated onto the release surface of the PET film using a scraper to achieve a dried resin composition layer thickness of 100 μm, resulting in a resin sheet. The obtained resin sheet was heated at 180°C for 90 minutes to thermally cure the resin composition layer, and a sheet-like cured product was obtained by peeling off the support. The cured product was cut into ring-shaped test pieces with an outer diameter of 19 mm and an inner diameter of 9 mm to prepare evaluation samples. The relative permeability (μ') of the evaluation sample was measured using a Keysight Technologies (16454A E4991B) at a room temperature of 23°C with the measurement frequency set to 100 MHz.

[0283] <Experimental Example 2: Determination of Tensile Fracture Point Strength>

[0284] The sheet-like cured material obtained in Example 1 was cut into dumbbell-shaped pieces (No. 1) to obtain test pieces. The tensile strength of these test pieces was determined using an ORIENTEC RTC-1250A tensile testing machine, and the breaking strength at 23°C was calculated. The determination was performed according to JIS K7127. This operation was performed three times, and the average values ​​are shown in the table.

[0285] The non-volatile components and their contents of the resin compositions of the examples and comparative examples, as well as the determination results of the test examples, are shown in Table 1 below.

[0286]

[0287] As can be seen from the above, by using a resin composition containing (A) magnetic powder and (B) thermosetting resin, wherein component (A) contains ferrite powder with an average particle size of less than 0.8 μm (A-1) and magnetic powder with an average particle size of more than 1.5 μm (A-2), and the volume ratio of component (A-2) to component (A-1) is 0.8 to 34.0, a magnetic material with excellent mechanical strength and relative permeability is obtained.

[0288] Symbol Explanation

[0289] 10-core substrate

[0290] 11 Supporting substrate

[0291] 12 First metal layer

[0292] 13 Second metal layer

[0293] 14 Through holes

[0294] 20 coating layers

[0295] 30a Resin Composition

[0296] 30 cured product

[0297] 40 Conductor Layer

[0298] 41 Patterned Conductor Layer

[0299] 100 Circuit Board

[0300] 200 Inner Layer Substrate

[0301] 200a First Main Surface

[0302] 200b Second Main Surface

[0303] 220 through hole

[0304] 220a Through-hole Wiring

[0305] 240 external terminals

[0306] 300 Magnetic Section

[0307] 310 Resin Sheets

[0308] 320a resin composition layer

[0309] 320 First cured layer

[0310] 330 Support

[0311] 340 Second cured layer

[0312] 360° via

[0313] 360a Through-hole Wiring

[0314] 400 coil-shaped conductive structure

[0315] 420 First conductor layer

[0316] 420A grounding

[0317] 440 Second conductor layer

Claims

1. A resin composition comprising (A) magnetic powder and (B) a thermosetting resin, (A) The composition includes (A-1) ferrite powder with an average particle size of less than 0.8 μm and (A-2) magnetic powder with an average particle size of more than 1.5 μm. The volume ratio of component (A-2) to component (A-1) (component (A-2) / component (A-1)) is 0.8 to 5.

0.

2. The resin composition according to claim 1, wherein, The average particle size of component (A-2) is less than 10.0 μm.

3. The resin composition according to claim 1, wherein, The average particle size of component (A-2) is less than 3.5 μm.

4. The resin composition according to claim 1, wherein, The average particle size of component (A-2) is greater than 2.5 μm.

5. The resin composition according to claim 1, wherein, The average particle size of component (A-2) is greater than 2.8 μm.

6. The resin composition according to claim 1, wherein, The average particle size of component (A-1) is above 0.01 μm.

7. The resin composition according to claim 1, wherein, The average particle size of component (A-1) is greater than 0.1 μm.

8. The resin composition according to claim 1, wherein, The average particle size of component (A-1) is greater than 0.12 μm.

9. The resin composition according to claim 1, wherein, The average particle size of component (A-1) is less than 0.3 μm.

10. The resin composition according to claim 1, wherein, The average particle size of component (A-1) is less than 0.2 μm.

11. The resin composition according to claim 1, wherein, The ratio of the average particle size of component (A-2) to the average particle size of component (A-1) (component (A-2) / component (A-1)) is 10 or more.

12. The resin composition according to claim 1, wherein, The ratio of the average particle size of component (A-2) to the average particle size of component (A-1) (component (A-2) / component (A-1)) is 15 or more.

13. The resin composition according to claim 1, wherein, The ratio of the average particle size of component (A-2) to the average particle size of component (A-1) (component (A-2) / component (A-1)) is less than 50.

14. The resin composition according to claim 1, wherein, The ratio of the average particle size of component (A-2) to the average particle size of component (A-1) (component (A-2) / component (A-1)) is less than 30.

15. The resin composition according to claim 1, wherein, (A-1) is composed of soft ferrite powder.

16. The resin composition according to claim 1, wherein, (A-1) The composition contains ferrite powder containing at least one element selected from Mn, Zn, Mg, Sr and Ni in addition to Fe.

17. The resin composition according to claim 1, wherein, (A-2) is composed of soft magnetic powder.

18. The resin composition according to claim 1, wherein, (A-2) The composition includes at least one magnetic powder selected from ferrite powder and magnetic alloy powder.

19. The resin composition according to claim 1, wherein, (A-2) contains magnetic alloy powder.

20. The resin composition according to claim 1, wherein, The content of component (A-1) is 0.5% by volume or more when the non-volatile component in the resin composition is 100% by volume.

21. The resin composition according to claim 1, wherein, The content of component (A-1) is 20% by volume or more when the non-volatile component in the resin composition is 100% by volume.

22. The resin composition according to claim 1, wherein, The content of component (A-1) is 50% by volume or less when the non-volatile component in the resin composition is 100% by volume.

23. The resin composition according to claim 1, wherein, The content of component (A-1) is 27% by volume or less when the non-volatile component in the resin composition is 100% by volume.

24. The resin composition according to claim 1, wherein, The content of component (A-1) is 0.5% by mass or more when the non-volatile component in the resin composition is 100% by mass.

25. The resin composition according to claim 1, wherein, The content of component (A-1) is 25% by mass or more when the non-volatile component in the resin composition is 100% by mass.

26. The resin composition according to claim 1, wherein, The content of component (A-1) is 70% by mass or less when the non-volatile component in the resin composition is 100% by mass.

27. The resin composition according to claim 1, wherein, The content of component (A-1) is 30% by mass or less when the non-volatile component in the resin composition is 100% by mass.

28. The resin composition according to claim 1, wherein, The content of component (A-2) is 10% by volume or more when the non-volatile component in the resin composition is 100% by volume.

29. The resin composition according to claim 1, wherein, The content of component (A-2) is 39% by volume or more when the non-volatile component in the resin composition is 100% by volume.

30. The resin composition according to claim 1, wherein, The content of component (A-2) is 80% by volume or less when the non-volatile component in the resin composition is 100% by volume.

31. The resin composition according to claim 1, wherein, The content of component (A-2) is 55% by volume or less when the non-volatile component in the resin composition is 100% by volume.

32. The resin composition according to claim 1, wherein, The content of component (A-2) is 20% by mass or more when the non-volatile component in the resin composition is 100% by mass.

33. The resin composition according to claim 1, wherein, The content of component (A-2) is 63% by mass or more when the non-volatile component in the resin composition is 100% by mass.

34. The resin composition according to claim 1, wherein, The content of component (A-2) is 95% by mass or less when the non-volatile component in the resin composition is 100% by mass.

35. The resin composition according to claim 1, wherein, The content of component (A-2) is 70% by mass or less when the non-volatile component in the resin composition is 100% by mass.

36. The resin composition according to claim 1, wherein, (A) The content of component A is 30% by volume or more when the non-volatile component in the resin composition is 100% by volume.

37. The resin composition according to claim 1, wherein, (A) The content of component A is 50% by volume or more when the non-volatile component in the resin composition is 100% by volume.

38. The resin composition according to claim 1, wherein, (A) The content of component A is 65% by volume or more when the non-volatile component in the resin composition is 100% by volume.

39. The resin composition according to claim 1, wherein, (A) The content of component A is 90% by volume or less when the non-volatile component in the resin composition is 100% by volume.

40. The resin composition according to claim 1, wherein, (A) The content of component A is 80% by volume or less when the non-volatile component in the resin composition is 100% by volume.

41. The resin composition according to claim 1, wherein, (A) The content of component A is 75% by volume or less when the non-volatile component in the resin composition is 100% by volume.

42. The resin composition according to claim 1, wherein, The volume ratio of component (A-2) to component (A-1) (component (A-2) / component (A-1)) is 1.1 or higher.

43. The resin composition according to claim 1, wherein, The volume ratio of component (A-2) to component (A-1) (component (A-2) / component (A-1)) is 2.5 or less.

44. The resin composition according to claim 1, wherein, (A) The content of component A is 50% by mass or more when the non-volatile component in the resin composition is 100% by mass.

45. The resin composition according to claim 1, wherein, (A) The content of component A is 92% by mass or more when the non-volatile component in the resin composition is 100% by mass.

46. ​​The resin composition according to claim 1, wherein, (A) The content of component A is 97% by mass or less when the non-volatile component in the resin composition is 100% by mass.

47. The resin composition according to claim 1, wherein, (A) The content of component A is 93% by mass or less when the non-volatile component in the resin composition is 100% by mass.

48. The resin composition according to claim 1, wherein, (B) Components include (B-1) epoxy resin.

49. The resin composition according to claim 48, wherein, The content of component (B-1) is 0.1% by mass or more when the non-volatile component in the resin composition is 100% by mass.

50. The resin composition according to claim 48, wherein, The content of component (B-1) is 5% by mass or more when the non-volatile component in the resin composition is 100% by mass.

51. The resin composition according to claim 48, wherein, The content of component (B-1) is 50% by mass or less when the non-volatile component in the resin composition is 100% by mass.

52. The resin composition according to claim 48, wherein, The content of component (B-1) is 10% by mass or less when the non-volatile component in the resin composition is 100% by mass.

53. The resin composition according to claim 48, wherein, Component (B) also contains (B-2) epoxy curing accelerator.

54. The resin composition according to claim 53, wherein, The content of component (B-2) is 0.01% by mass or more when the non-volatile components in the resin composition are 100% by mass.

55. The resin composition according to claim 53, wherein, The content of component (B-2) is 0.5% by mass or more when the non-volatile component in the resin composition is 100% by mass.

56. The resin composition according to claim 53, wherein, The content of component (B-2) is 10% by mass or less when the non-volatile component in the resin composition is 100% by mass.

57. The resin composition according to claim 53, wherein, The content of component (B-2) is less than 1% by mass when the non-volatile component in the resin composition is 100% by mass.

58. The resin composition according to claim 1, wherein, (B) The content of component is 0.1% by mass or more when the non-volatile component in the resin composition is 100% by mass.

59. The resin composition according to claim 1, wherein, (B) The content of component (B) is 5% by mass or more when the non-volatile component in the resin composition is 100% by mass.

60. The resin composition according to claim 1, wherein, (B) The content of component (B) is 50% by mass or less when the non-volatile component in the resin composition is 100% by mass.

61. The resin composition according to claim 1, wherein, (B) The content of component (B) is 10% by mass or less when the non-volatile component in the resin composition is 100% by mass.

62. The resin composition according to claim 1, wherein, The tensile breaking strength of the cured resin composition, as determined according to JIS K7127, is 60 MPa or higher.

63. The resin composition according to claim 1, wherein, The relative magnetic permeability (μ') of the cured resin composition measured at a frequency of 100 MHz and a temperature of 23 °C is 10.0 or higher.

64. The cured product of the resin composition according to any one of claims 1 to 63.

65. A resin sheet comprising a support and a resin composition layer formed of any one of claims 1 to 63 disposed on the support.

66. A circuit board comprising: a substrate having through holes, and a cured product of the resin composition of any one of claims 1 to 63 filled in the aforementioned through holes.

67. An inductor substrate comprising the circuit substrate of claim 66.

68. A circuit board comprising a cured layer as a cured product of the resin composition according to any one of claims 1 to 63.

69. An inductor substrate comprising the circuit substrate of claim 68.

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