Substrate with magnetic body part, substrate with conductor part, electronic component, and production method for substrate with conductor part

Abstract

The first problem addressed by the present invention is to provide a substrate with a magnetic body part that does not readily shed particles or crack when the magnetic body part is drilled. The second problem addressed by the present invention is to provide a substrate with a conductor part, an electronic component, and a production method for the substrate with a conductor part.　This substrate with a magnetic body part includes: a substrate that has a through hole; and a magnetic body part that includes magnetic particles and has been filled into the through hole. The Vickers hardness of the magnetic body part is 56–160 HV.

Description

Substrate with magnetic material, substrate with conductive material, electronic component, method for manufacturing substrate with conductive material

[0001] The present invention relates to a substrate with a magnetic material portion, a substrate with a conductive portion, an electronic component, and a method for manufacturing a substrate with a conductive portion.

[0002] With the increasing performance and miniaturization of electronic devices, the integration density of electronic circuit boards is also increasing. Against this backdrop, research is progressing on substrates in which magnetic materials are mounted in arbitrary shapes by using compositions containing magnetic particles.

[0003] For example, Patent Document 1 describes a study on using a cured product of a composition containing magnetic particles as a magnetic material.

[0004] International Publication No. 2024 / 043162

[0005] Recently, in the manufacture of electronic components such as inductors, a magnetic substrate is sometimes used, which comprises a substrate having through holes and a magnetic material portion filled in the through holes. The magnetic material portion is then drilled to form through holes, and a conductive portion is formed on the side wall of the through hole by a method such as plating. Typically, the magnetic material portion is formed by filling the through holes of the substrate with a composition of magnetic particles and epoxy compounds and then curing it. The present inventors, referring to Patent Document 1, have manufactured a substrate with a magnetic material portion formed in the through holes of a substrate and investigated its performance. They have found that when drilling is performed on the magnetic material portion to form through holes, particle shedding or cracking may occur on the side wall of the through hole (in other words, the wall surface of the magnetic material portion on the through hole side). When particle shedding or cracking occurs on the side wall of the through hole of the magnetic material portion, the thickness of the conductive portion formed on the side wall of the through hole by a method such as plating may not be uniform, and the desired conductivity may not be achieved.

[0006] Therefore, the object of the present invention is to provide a substrate with a magnetic material portion that is less prone to grain detachment and cracking when the magnetic material portion is drilled. The object of the present invention is also to provide a substrate with a conductive portion, an electronic component, and a method for manufacturing a substrate with a conductive portion.

[0007] The present inventors have found that the above problem can be solved by the following configuration.

[0008] [1] A substrate with a magnetic portion, comprising: a substrate having a through hole; and a magnetic portion containing magnetic particles filled in the through hole, wherein the Vickers hardness of the magnetic portion is 56 to 160 HV. [2] The substrate with a magnetic portion according to [1], wherein the content of the magnetic particles is 85% by mass or more based on the total mass of the magnetic portion. [3] The substrate with a magnetic portion according to [1] or [2], wherein the magnetic particles include ferrite particles, and the content of the ferrite particles is 70% by mass or more based on the total mass of the magnetic particles. [4] The substrate with a magnetic portion according to any one of [1] to [3], wherein the magnetic particles are spherical magnetic particles. [5] The substrate with a magnetic portion according to any one of [1] to [4], wherein in the volume frequency particle size distribution of the magnetic particles, there are at least two peak tops, a particle diameter at one peak top is 35 to 45 µm, and a particle diameter at the other peak top is 1 to 5 µm. [6] The substrate with a magnetic portion according to any one of [1] to [5], wherein the magnetic portion includes a cured product of an epoxy compound. [7] A substrate with a conductor portion, comprising the substrate with a magnetic portion according to any one of [1] to [6] and a conductor portion, wherein the magnetic portion of the substrate with a magnetic portion has a through hole, and the conductor portion is disposed on a side wall of the through hole of the magnetic portion. [8] The substrate with a conductor portion according to [7], wherein a ratio of the shortest distance in an in-plane direction of the substrate from an outer edge of the through hole of the substrate to an outer edge of the through hole of the magnetic portion with respect to a thickness of the conductor portion is 5 to 20. [9] An electronic component comprising the substrate with a conductor portion according to [7] or [8].

[10] A method for manufacturing a substrate with a conductor portion, comprising: Step I of forming, in the through hole of a substrate having a through hole, a magnetic portion containing magnetic particles and having a Vickers hardness of 56 to 160 HV; Step II of forming a through hole in the magnetic portion; and Step III of forming a conductor portion on a side wall of the through hole of the magnetic portion.

[0009] According to the present invention, it is possible to provide a substrate with a magnetic part that is less prone to grain falling and cracking when the magnetic part is drilled. Furthermore, according to the present invention, a substrate with a conductor part, an electronic component, and a method for manufacturing a substrate with a conductor part can also be provided.

[0010] It is a schematic diagram showing an example of an embodiment of a substrate with a magnetic part according to the present invention. It is a schematic diagram showing an example of an embodiment of a substrate with a conductor part according to the present invention. It is a schematic diagram showing a cross-section in a direction orthogonal to the thickness direction of the substrate with a conductor part shown in Fig. 2.

[0011] Hereinafter, the present invention will be described in detail. The description of the constituent requirements set forth below may be made based on typical embodiments of the present invention, but the present invention is not limited to such embodiments. Regarding the notation of groups (atomic groups) in the present specification, unless it is contrary to the gist of the present invention, a notation that does not specify substituted or unsubstituted includes both groups having no substituent and groups having a substituent. For example, the term "alkyl group" includes not only alkyl groups having no substituent (unsubstituted alkyl groups) but also alkyl groups having a substituent (substituted alkyl groups). In addition, the term "organic group" as used herein refers to a group containing at least one carbon atom.

[0012] In the present specification, the term "to" is used in the sense that it includes the numerical values described before and after it as the lower limit and the upper limit.

[0013] In the present specification, (meth)acrylate represents acrylate and methacrylate, (meth)acryl represents acryl and methacryl, and (meth)acryloyl represents acryloyl and methacryloyl.

[0014] In the present specification, the "solid content" of a composition means the components that form the magnetic part. Therefore, when the composition contains a solvent (organic solvent, water, etc.), it means all components excluding the solvent. Note that any component that forms the magnetic part, even liquid components are regarded as solid content.

[0015] In the present specification, "boiling point" means standard boiling point unless otherwise specified. In the present specification, 1 Torr can be converted as 1 mmHg.

[0016] Furthermore, in this specification, the weight-average molecular weight (Mw) is the polystyrene-converted value obtained by GPC (Gel Permeation Chromatography). In this specification, the GPC method is based on using HLC-8020GPC (manufactured by Tosoh Corporation), TSKgel SuperHZM-H, TSKgel SuperHZ4000, and TSKgel SuperHZ2000 (manufactured by Tosoh Corporation, 4.6 mm ID × 15 cm) as columns, and THF (tetrahydrofuran) as the eluent.

[0017] Furthermore, in this specification, unless otherwise specified, each component may be represented by a single substance or by a combination of two or more substances. Here, when two or more substances are used in combination for each component, the content of that component refers to the total content of the combined substances, unless otherwise specified.

[0018] [Substrate with Magnetic Material] A notable feature of the substrate with a magnetic material of the present invention is that the Vickers hardness of the magnetic material is set to 56 to 160 HV. With the above-mentioned substrate with a magnetic material, when drilling into the magnetic material to form through holes, it is possible to suppress the shedding of grain and cracking of the side walls of the through holes in the magnetic material (in other words, the wall surface of the magnetic material on the through-hole side) that may occur due to contact with the rotating body of the drill and vibration of the rotating body of the drill.

[0019] Hereinafter, when the magnetic material portion of a substrate with a magnetic material portion is drilled, the ability to further suppress grain detachment and cracking is also referred to as "the effect of the present invention is superior."

[0020] The configuration of the substrate with a magnetic material will be described below with reference to the drawings. Figure 1 is a schematic diagram showing an example of an embodiment of the substrate with a magnetic material. The substrate with a magnetic material 10 shown in Figure 1 has a substrate 11, a plurality of through holes 13 provided in the substrate 11, and magnetic material parts 15 filled in the through holes 13. The through holes 13 are through holes that penetrate in the thickness direction Dt of the substrate 11. Note that Figure 1 is a schematic diagram, and the shape and positional relationships do not necessarily match those of the actual product. In the substrate with a magnetic material, the arrangement position of the magnetic material on the substrate and the shape of the magnetic material are arbitrary and not particularly limited. The constituent members of the substrate with a magnetic material will be described in detail below.

[0021] [Substrate] Examples of substrates in a substrate with a magnetic material include glass substrates, glass epoxy substrates (e.g., FR (Flame Retardant)-4, FR-5, CEM-3 (Composite epoxy material-3), etc.), silicon substrates, and resin substrates. The substrate may be composed of a light-transmitting substrate such as a glass substrate. Examples of substrates include tempered glass such as Gorilla Glass (manufactured by Corning). Examples of materials that may be included in the above substrate include the materials used in Japanese Patent Publication No. 2010-086684, Japanese Patent Publication No. 2010-152809, and Japanese Patent Publication No. 2010-257492. Examples of resin substrates include polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), polyimide, polyethylene naphthalate, polycarbonate, triacetylcellulose, and cycloolefin polymer. The substrate may also have a wiring layer formed on it, and may be single-layer or multi-layer.

[0022] A substrate typically has multiple through-holes that penetrate in the thickness direction of the substrate. In a substrate with a magnetic material, the through-holes are filled with the magnetic material. The shape of the through-holes (the shape of the opening of the through-holes) in a cross-section perpendicular to the thickness direction of the substrate is not particularly limited, but it is preferably circular. In Figure 1, the shape of the opening of the through-holes is circular. The arrangement of the through-holes on the substrate is not particularly limited; for example, they may be arranged not only in a grid pattern with an interior angle of 90°, but also in a hexagonal grid pattern with an interior angle of 60°, i.e., a honeycomb pattern. Furthermore, the spacing between the through-holes on the substrate is not particularly limited.

[0023] [Magnetic Material] In a substrate with a magnetic material, the magnetic material is filled into through-holes that penetrate the substrate in the thickness direction, and its shape is usually approximately the same as the shape of the through-holes in the substrate. The magnetic material is typically columnar, and its shape is not particularly limited, but it may be cylindrical or rectangular, for example. In Figure 1, the magnetic material is cylindrical. The magnetic material extends in the thickness direction Dt of the substrate, and the shape of the cross-section in the direction perpendicular to the thickness direction Dt of the substrate is determined by the shape of the opening of the through-hole, which will be described later. If the shape of the opening of the through-hole is circular, the magnetic material will be cylindrical. The position of the magnetic material is the same as the position of the through-holes in the substrate, since the magnetic material is filled into the through-holes in the substrate.

[0024] The following describes the various components contained in the magnetic material.

[0025] <Magnetic Particles> The magnetic portion includes magnetic particles. The magnetic particles typically contain metal atoms. In this specification, the metal atoms also include metalloid atoms such as boron, silicon, germanium, arsenic, antimony, and tellurium. The metal atoms may be included as alloys, metal oxides, metal nitrides, or metal carbides containing metal elements.

[0026] The above metal atoms are not particularly limited, but it is preferable that they include at least one metal atom selected from the group consisting of Fe, Ni, Co, Zn, and Mn. The content of at least one metal atom selected from the group consisting of Fe, Ni, Co, Zn, and Mn (or the total content if multiple types are included) is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, based on the total mass of metal atoms in the magnetic particles. The upper limit of the above content is not particularly limited, for example, it is 100% by mass or less, preferably 98% by mass or less, and more preferably 95% by mass or less.

[0027] The magnetic particles may contain atoms other than Fe, Ni, Co, Zn, and Mn. Specific examples include Al, Si, S, Sc, Ti, V, Cu, Y, Mo, Rh, Pd, Ag, Sn, Sb, Te, Ba, Ta, W, Re, Au, Bi, La, Ce, Pr, Nd, P, Sr, Zr, Cr, Nb, Pb, Ca, B, C, N, and O. When the magnetic particles contain metal atoms other than Fe, Ni, Co, Zn, and Mn, it is preferable that the magnetic particles further contain one or more atoms selected from the group consisting of Si, Cr, B, and Mo.

[0028] The shape of the magnetic particles is not particularly limited and may be plate-shaped, elliptical, spherical, or amorphous, but a spherical shape is preferred because it provides superior magnetic permeability.

[0029] The magnetic particles are preferably ferrite particles or alloy particles, and more preferably ferrite particles. The ferrite particles preferably contain at least one metal atom selected from the group consisting of Ni, Mn, and Co, in addition to Fe which constitutes iron oxide, and more preferably contain one or more atoms selected from the group consisting of Ni and Mn. Furthermore, the ferrite particles may contain atoms other than Fe, Ni, Mn, and Co, and specific examples include Al, Si, S, Sc, Ti, V, Cu, Y, Mo, Rh, Pd, Ag, Sn, Sb, Te, Ba, Ta, W, Re, Au, Bi, La, Ce, Pr, Nd, P, Zn, Sr, Zr, Cr, Nb, Pb, Ca, B, C, N, and O.

[0030] Specific examples of ferrite particles include Ni ferrite, Mn ferrite, and spinel ferrite (preferably Ni-Zn ferrite, Mn-Zn ferrite, Ni-Zn-Co ferrite, Fe-CO ferrite, Fe-Mn ferrite).

[0031] As described above, alloy particles are also preferably used as magnetic particles. Alloy particles are preferably those containing Fe because they have superior magnetic permeability. Examples of metal atoms other than Fe in alloy particles include Ni and Co. When alloy particles contain Fe, the Fe content is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, relative to the total metal atom content in the alloy particles. The upper limit of the above content is not particularly limited, for example, it is 100% by mass or less, preferably 98% by mass or less, and more preferably 95% by mass or less. Furthermore, the alloy particles may be amorphous.

[0032] Specific examples of alloy particles include Fe-Co alloy particles (preferably Permendur), Fe-Ni alloy particles (e.g., Permalloy), Fe-Zr alloy particles, Fe-Mn alloy particles, Fe-Si alloy particles, Fe-Al alloy particles, Ni-Mo alloy particles (preferably Supermalloy), Fe-Ni-Co alloy particles, Fe-Si-Cr alloy particles, Fe-Si-B alloy particles, Fe-Si-Al alloy particles (preferably Sendust), Fe-Si-B-C alloy particles, Fe-Si-B-Cr alloy particles, Fe-Si-B-Cr-C alloy particles, Fe-Co-Si-B alloy particles, Fe-Si-B-Nb alloy particles, Fe nanocrystalline alloy particles, Fe-based amorphous alloy particles, and Co-based amorphous alloy particles.

[0033] A surface layer may be provided on at least a portion of the surface of the magnetic particles. Having a surface layer allows the magnetic particles to be given functions depending on the material of the surface layer. Examples of surface layers include inorganic layers and organic layers, with organic layers being preferred.

[0034] As compounds for forming the inorganic layer, metal oxides, metal nitrides, metal carbides, metal phosphate compounds, metal borate compounds, or silicate compounds (for example, silicate esters such as tetraethyl orthosilicate, and silicates such as sodium silicate) are preferred because they can form a surface layer that is excellent in at least one of the following: insulating properties, gas barrier properties, and chemical stability. Specific examples of elements contained in these compounds include Fe, Al, Ca, Mn, Zn, Mg, V, Cr, Y, Ba, Sr, Ge, Zr, Ti, Si, and rare earth elements. Materials constituting the inorganic layer obtained using the inorganic layer-forming compound include silicon oxide, germanium oxide, titanium oxide, aluminum oxide, zirconium oxide, and magnesium oxide, and the inorganic layer may contain two or more of these materials.

[0035] Examples of compounds for forming organic layers include acrylic monomers. Specific examples of acrylic monomers include the compounds described in paragraphs 0022 to 0023 of Japanese Patent Publication No. 2019-067960. Examples of materials for forming the organic layer obtained using the organic layer-forming compound include acrylic resins.

[0036] The thickness of the surface layer is not particularly limited, but 3 to 1000 nm is preferred in that the surface layer's function is better demonstrated.

[0037] The volume-average particle diameter (D50) of the magnetic particles is not particularly limited, but is preferably 1 to 100 μm. D50 is the so-called median diameter. The volume-average particle diameter (D50) of the magnetic particles can be determined based on the particle size distribution curve (volume-frequency particle size distribution) that represents the volume-based frequency distribution of the magnetic particles, obtained using a laser diffraction scattering particle size distribution analyzer (for example, the "LA960N" product manufactured by Horiba, Ltd.). It is preferable to perform the above measurement on magnetic particles separated from the magnetic material. As a method for separating magnetic particles from the magnetic material, for example, a method in which the resin component of the magnetic material is dissolved or decomposed with a solvent, acid, base, or ozone, and then removed by centrifugal sedimentation can be used. If the raw material magnetic particles are known, the volume-frequency particle size distribution can be determined based on the volume-frequency particle size distribution of the raw material magnetic particles.

[0038] Furthermore, the magnetic particles may have only one peak top in their volume-frequency-particle-size distribution, or they may have two or more. In terms of having higher magnetic permeability in the magnetic material portion, it is more preferable that the volume-frequency-particle-size distribution of the magnetic particles has at least two peak tops, with the particle diameter at one peak top being 35 to 45 μm and the particle diameter at the other peak top being 1 to 5 μm.

[0039] In terms of superior magnetic permeability, the magnetic material portion preferably contains two or more types of magnetic particles, and the volume-average particle diameters (D50) of the two or more types of magnetic particles are different from each other. When the magnetic material portion contains two or more types of magnetic particles, it is also preferable that at least one of the two or more types of magnetic particles has a volume-average particle diameter (D50) of 10 μm or more (hereinafter also referred to as the "first magnetic particle"), and at least one of the two or more types of magnetic particles has a volume-average particle diameter (D50) of less than 10 μm (hereinafter also referred to as the "second magnetic particle"). The lower limit of the volume-average particle diameter (D50) of the first magnetic particle is more preferably 20 μm or more, even more preferably 30 μm or more, and particularly preferably 35 μm or more. The upper limit is preferably 100 μm or less, more preferably 80 μm or less, even more preferably 60 μm or less, and particularly preferably 45 μm or less. The upper limit of the volume-average particle diameter (D50) of the second magnetic material particles is more preferably 8 μm or less, even more preferably 7 μm or less, and particularly preferably 5 μm or less. The lower limit is preferably 0.002 μm or more, more preferably 0.04 μm or more, and even more preferably 0.06 μm or more.

[0040] Furthermore, the above-mentioned second magnetic particles may also preferably include magnetic particles with a volume-average particle diameter (D50) of 1 μm or more and less than 10 μm (hereinafter also referred to as "second A magnetic particles") and magnetic particles with a volume-average particle diameter (D50) of less than 1 μm (hereinafter also referred to as "second B magnetic particles"). The upper limit of the volume-average particle diameter (D50) of the second A magnetic particles is more preferably 8 μm or less, even more preferably 7 μm or less, and particularly preferably 5 μm or less. The upper limit of the volume-average particle diameter (D50) of the second B magnetic particles is preferably 0.8 μm or less, and more preferably 0.3 μm or less. The lower limit is preferably 0.002 μm or more, more preferably 0.04 μm or more, and even more preferably 0.06 μm or more.

[0041] The lower limit of the content of the first magnetic particles is preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 35% by mass or more, and particularly preferably 40% by mass or more, relative to the total content of magnetic particles. The upper limit is preferably 75% by mass or less, more preferably 70% by mass or less, even more preferably 65% ​​by mass or less, and particularly preferably 60% by mass or less, relative to the total content of magnetic particles.

[0042] The lower limit of the content of the second magnetic particles is preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 35% by mass or more, and particularly preferably 40% by mass or more, relative to the total content of magnetic particles. The upper limit is preferably 75% by mass or less, more preferably 70% by mass or less, even more preferably 65% ​​by mass or less, and particularly preferably 60% by mass or less, relative to the total content of magnetic particles.

[0043] Furthermore, it is preferable that the first magnetic particles and the second magnetic particles have different compositions. It is also preferable that the second A magnetic particles and the second B magnetic particles have different compositions. Examples of combinations of magnetic particles with different compositions include combinations of ferrite particles and alloy particles, and combinations of ferrite particles containing different types of metal elements, as will be described later. An example of a preferred embodiment of the first magnetic particles and the second magnetic particles is an embodiment in which both the first and second magnetic particles are ferrite particles. Specifically, this includes an embodiment in which the first magnetic particles are ferrite particles selected from Ni-Zn ferrite and Ni-Zn-Co ferrite, and the second magnetic particles are ferrite particles selected from Mn ferrite and Fe-Co ferrite.

[0044] Furthermore, while the upper section described an embodiment in which the magnetic material contains two or more types of magnetic particles and the volume-average particle sizes (D50) of the two or more types of magnetic particles are different from each other, it is also preferable for the magnetic material to contain two or more types of magnetic particles and for the compositions of the two or more types of magnetic particles to be different from each other, in that it has superior magnetic permeability.

[0045] When the magnetic material contains two or more magnetic particles with different compositions, the combination of magnetic particles is preferably a combination of first ferrite particles and second ferrite particles, or a combination of ferrite particles and alloy particles, and more preferably a combination of first ferrite particles and second ferrite particles. Here, the first ferrite particles and second ferrite particles are intended to be ferrite particles containing different types of metal elements. In other words, the second ferrite particles are ferrite particles containing a different type of metal element than the first ferrite particles. Examples of combinations of first and second ferrite particles include a combination in which the first ferrite particles are selected from Ni-Zn ferrite and Ni-Zn-Co ferrite, and the second ferrite particles are selected from Mn ferrite and Fe-Co ferrite. When using a combination of first ferrite particles and second ferrite particles as magnetic particles, the content ratio (mass ratio: first ferrite particles / second ferrite particles) is preferably 30 / 70 to 70 / 30, and more preferably 40 / 60 to 60 / 40. Furthermore, when using a combination of ferrite particles and alloy particles as magnetic particles, the content ratio (mass ratio: ferrite particles / alloy particles) is preferably 30 / 70 to 70 / 30, and more preferably 40 / 60 to 60 / 40. The magnetic particles may also include two or more ferrite particles as second ferrite particles, each containing a different type of metal element than the first ferrite particles.

[0046] Furthermore, if the magnetic particles include first and second magnetic particles with different compositions, the volume-average particle size (D50) of the first and second magnetic particles can be measured by the following method. If the raw materials of the first and second magnetic particles, which have different compositions, are known, the volume-average particle size can be determined based on the volume-frequency particle size distribution of each raw material constituting the magnetic particles.

[0047] First, magnetic particles are separated from the magnetic material. Methods for separating magnetic particles from the magnetic material include, for example, dissolving or decomposing the resin component of the magnetic material with a solvent, acid, base, or ozone, and then removing it by centrifugal sedimentation. The separated magnetic particles are observed using a transmission microscope, and images are taken at a magnification of 100,000x in an arbitrary observation field. During this observation, the elemental composition is analyzed based on energy-dispersive X-ray spectroscopy (EDS), and at least 100 magnetic particles with the same composition are extracted. In other words, at least 100 particles are extracted for each of the first and second magnetic particles. Next, based on the elemental analysis results described above, the particle images obtained by printing on photographic paper at a total magnification of 500,000x are used to trace the contours of the particles (primary particles) extracted as first and second magnetic particles using a digitizer, and the circular area phase diameter (wherein the circular area phase diameter is the diameter of a perfect circle assuming the same area as the traced region) is calculated. Here, primary particles refer to independent particles that are not aggregated. Furthermore, imaging using a transmission electron microscope shall be performed by the direct method using a transmission electron microscope with an acceleration voltage of 300 kV. Transmission electron microscope observation and measurement can be performed, for example, using a Hitachi H-9000 transmission electron microscope and Carl Zeiss KS-400 image analysis software. From the at least 100 first magnetic particles for which the circular area phase diameter was calculated above, 100 particles are arbitrarily extracted, and the volume of each particle is calculated using the following formula (1). Formula (1): Volume = (Circular area phase diameter of magnetic particles) ３ × (π / 6) Based on the volume and circular area phase diameter of each magnetic particle obtained above, a particle size distribution curve (volume frequency particle size distribution) representing the volume-based frequency distribution is obtained, and the volume average particle size (D50) is determined for each. Similarly, for the second magnetic particle, the volume frequency particle size distribution is obtained using the same method as for the first magnetic particle, and the volume average particle size (D50) is determined.

[0048] Furthermore, if the magnetic particles include first magnetic particles, second A magnetic particles, and second B magnetic particles, each having a different composition, the volume-average particle diameter (D50) of the first magnetic particles, second A magnetic particles, and second B magnetic particles can also be determined in accordance with the method described above.

[0049] The magnetic particles preferably include ferrite particles, and the ferrite particle content is preferably 70% by mass or more of the total mass of the magnetic particles. More preferably, the ferrite particle content is 85% by mass or more of the total mass of the magnetic particles, and even more preferably 90% by mass or more. The upper limit is preferably 100% by mass or less.

[0050] In the magnetic material portion, the lower limit of the content of magnetic particles (total content if multiple types are included) is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more, relative to the total mass of the magnetic material portion. The upper limit is preferably 98% by mass or less, and more preferably 96% by mass or less, relative to the total mass of the magnetic material portion.

[0051] <Resin> The magnetic material preferably further contains a resin. The resin is not particularly limited as long as it can hold magnetic particles within the magnetic material portion, but it is preferably a cured product of a compound having an epoxy group (epoxy compound) or a compound having an oxetanyl group (oxetanyl compound). The resin may also contain a resin that was used as a dispersant and a vibration modifier in the composition forming the magnetic material portion.

[0052] <Other Components> The magnetic material portion may further contain other components besides those described above. Examples of other components include known additives such as fillers such as silica, plasticizers, surfactants, and auxiliary agents (e.g., defoamers, flame retardants, leveling agents, peeling accelerators, antioxidants, fragrances, surface tension modifiers, and chain transfer agents).

[0053] <Properties of the Magnetic Material> The Vickers hardness of the magnetic material is 56 to 160 HV. The above Vickers hardness is obtained by taking 50 measurements using a Vickers hardness tester under the condition of a load of 1000 mN / 10 seconds, and taking the average value. As a Vickers hardness tester, for example, a microhardness tester manufactured by Fischer Instruments Co., Ltd. can be used. The Vickers hardness is preferably 70 to 160 HV, and more preferably 85 to 160 HV, in terms of achieving superior effects of the present invention. The Vickers hardness can be adjusted to the above numerical range by appropriately adjusting the various materials that can constitute the composition containing magnetic particles for forming the magnetic material (for example, epoxy compounds, curing accelerators, and curing agents, etc.) and the curing conditions of the composition (for example, heating conditions such as heating time, heating temperature, and heating procedure). The composition containing magnetic particles will be described in detail later.

[0054] <Composition> The magnetic material portion can be formed from a composition containing magnetic particles (hereinafter also referred to as "composition"). The composition will be described below. (Magnetic Particles) The composition contains magnetic particles. The type and composition of magnetic particles contained in the composition are the same as those contained in the magnetic material portion described above, and the preferred embodiments are also the same. The total content of magnetic particles in the composition is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more, based on the total solid content in the composition. The upper limit is preferably 98% by mass or less, and more preferably 96% by mass or less, based on the total solid content in the composition.

[0055] (Polymerizable Compound) The composition preferably contains a polymerizable compound. The polymerizable compound is a compound having a polymerizable group. The polymerizable group is preferably a cyclic polymerizable group, and preferably an epoxy group or an oxetanyl group. In other words, the composition preferably contains a compound having an epoxy group and / or an oxetanyl group as the polymerizable compound. The polymerizable compound preferably contains one or more groups selected from the group consisting of epoxy groups and oxetanyl groups, more preferably two or more, and preferably three or more. The upper limit is, for example, 15 or less. Note that the epoxy group and the oxetanyl group may be fused with a cyclic group (alicyclic group, etc.). The number of carbon atoms in the cyclic group fused with the epoxy group is preferably 5 to 15. In addition, in the above cyclic group, the part other than the fused epoxy group may be monocyclic or polycyclic. A single cyclic group may have only one epoxy group fused with it, or it may have two or more epoxy groups fused with it.

[0056] Among polymerizable compounds, polyfunctional epoxy compounds (compounds having two or more epoxy groups) are preferred. Polyfunctional epoxy compounds are more preferably those containing two or more epoxy groups, and more preferably those containing three or more, as this makes it easier to adjust the Vickers hardness of the formed magnetic material within a predetermined range, thereby enhancing the effects of the present invention. Furthermore, polyfunctional epoxy compounds are also preferably those containing aromatic rings, as this makes it easier to adjust the Vickers hardness of the formed magnetic material within a predetermined range, thereby enhancing the effects of the present invention. Additionally, polyfunctional epoxy compounds are also preferably those represented by formula (EP1) or formula (EP2), as this makes it easier to adjust the Vickers hardness of the formed magnetic material within a predetermined range, thereby enhancing the effects of the present invention.

[0057] Formula (EP1) X - (R １ -O)m-R ２ In the formula, X represents a glycidyl ether group. １ R represents a linear (linear or branched) alkylene group, which may have substituents. １ The number of carbon atoms in the alkylene group represented by is preferably 1 to 6. Also, R １Examples of the substituents that may be possessed include a glycidyl ether group, a hydroxyl group, and the like. m represents an integer of 1 or greater, and an integer of 1 to 4 is preferable. In the formula, -(R １ -O)m-, in the structural site represented by this formula, the number of atoms in the chain structure portion excluding substituents is preferably 50 or less, more preferably 24 or less, and still more preferably 16 or less. In the formula, when m represents an integer of 2 or greater, the plurality of existing R １ may be the same as or different from each other.

[0058] R ２ represents a glycidyl group, a hydrogen atom, or an alkyl group that may have a substituent. R ２ The alkyl group represented by preferably has 1 to 6 carbon atoms. R ２ Examples of the substituents that the alkyl group represented by may have include a hydroxyl group and the like. R ２ particularly preferably represents a glycidyl group. Provided that the compound represented by formula (EP1) has at least two epoxy groups. The compound represented by formula (EP1) preferably has at least three epoxy groups, more preferably has 3 to 8 epoxy groups, and still more preferably has 3 to 6 epoxy groups, from the viewpoint that the Vickers hardness in the formed magnetic portion can be easily adjusted to a predetermined range and the effect of the present invention is more easily obtained. The compound represented by formula (EP1) is preferably a polyfunctional epoxy compound having a structural site derived from, for example, glycerol, polyglycerol (preferably having an average addition number of 2 to 3), sorbitol, trimethylol, and pentaerythritol.

[0059] Formula (EP2) AR-(Y)n In the formula, Y represents a glycidyl ether group or a diglycidylamine group. n represents an integer of 2 or greater. The upper limit is not particularly limited, but for example, an integer of 10 or less is preferable, 2 to 6 is more preferable, and 2 to 4 is still more preferable.

[0060] AR is (A ｒ１ -L Ｘ )p-A ｒ２ represents an n-valent linking group formed by removing n hydrogen atoms from the structure represented by. A ｒ１ and A ｒ２Each of these independently represents an aromatic ring which may have substituents. Examples of the aromatic ring include aromatic hydrocarbon rings and aromatic heterocycles, with aromatic hydrocarbon rings being preferred, benzene rings or naphthalene rings being more preferred, and benzene rings being even more preferred. The aromatic ring may further have substituents. Substituents are not particularly limited, but examples include alkyl groups, alkoxy groups, alkoxycarbonyl groups, acyloxy groups, hydroxyl groups, and halogen atoms. Ｘ is a single bond or -CR ３ R ４ Represents -. R ３ and R ４ Each independently represents a hydrogen atom, an optionally substituted alkyl group, or an optionally substituted monovalent aromatic ring group. ３ and R ４ The number of carbon atoms in the alkyl group represented by is preferably 1 to 6. ３ and R ４ Examples of substituents that the alkyl group represented by may have include a phenyl group which may have substituents. ３ and R ４ Examples of monovalent aromatic ring groups represented by include monovalent aromatic hydrocarbon ring groups and monovalent aromatic heterocyclic ring groups, among which monovalent aromatic hydrocarbon ring groups are preferred, phenyl groups or naphthyl groups are more preferred, and phenyl groups are even more preferred. ３ and R ４ Examples of substituents that the monovalent aromatic ring group represented by may have include alkyl groups. Ｘ Among them, -CH ２ It is preferable to represent -. p represents an integer greater than or equal to 0. There is no particular upper limit, but for example, an integer less than or equal to 10 can be given. Among these, p is preferably 0 or 1, and more preferably 0. When p represents 0, AR is A ｒ２This represents an n-valent linking group formed by removing n hydrogen atoms from the aromatic ring represented by . However, the compound represented by formula (EP2) preferably has at least 3 epoxy groups, more preferably 3 to 8, and even more preferably 3 to 6, in that the Vickers hardness of the formed magnetic material can be easily adjusted to a predetermined range, and the effects of the present invention are more easily achieved. Note that AR is A ｒ１ and A ｒ２ It is preferable that the linking group is an n-valent group formed by removing n hydrogen atoms from the aromatic ring represented by .

[0061] The polyfunctional epoxy compound is not particularly limited, but examples include alicyclic epoxy resins, aromatic epoxy resins, aliphatic polyglycidyl ethers, bisphenol A type epoxy resins, bisphenol F type epoxy resins, phenol novolac type epoxy resins, and cresol novolac type epoxy resins.

[0062] Specific examples of polyfunctional epoxy compounds include, for example, Epolid® GT401, Epolid PB3600, Epolid PB4700, Celoxide® 2021, Celoxide 3000, EHPE3150 (all manufactured by Daicel Corporation); jER1001, jER1002, jER1003, jER1004, jER1007, jER1009, jER1010, jER828, jER871, jER872, jER180S75, jER807, jER890, jER152, jER154, jERYX7400N (all manufactured by Mitsubishi Chemical Corporation); YED216 (manufactured by Mitsubishi Chemical Corporation); EPPN201, EPPN202 Examples include EOCN-102, EOCN-103S, EOCN-104S, EOCN-1020, EOCN-1025, EOCN-1027 (all manufactured by Nippon Kayaku Co., Ltd.); Epiclon® 200, Epiclon 400 (both manufactured by DIC Corporation); Denacol® EX-611, Denacol EX-612, Denacol EX-614, Denacol EX-622, Denacol EX-411, Denacol EX-512, Denacol EX-522, Denacol EX-421, Denacol EX-313, Denacol EX-314, Denacol EX-321 (all manufactured by Nagase ChemteX Corporation); and TEPIC-S (manufactured by Nissan Chemical Industries, Ltd.). Other examples of polyfunctional epoxy compounds include ethyl 3-methyl-3-phenylglycidate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 4,4'-methylenebis(N,N-diglycidylaniline) (manufactured by Tokyo Chemical Industries, Ltd.), and N,N-diglycidyl-4-glycidyloxyaniline (manufactured by Sigma-Aldrich).

[0063] Furthermore, examples of compounds having an oxacenyl group include "OXT-101" (3-ethyl-3-hydroxymethyloxetane), "OXT-121" (1,4-bis-3-ethyloxetane-3-ylmethoxymethylbenzene), "OXT-221" (bis-1-ethyl-3-oxetanylmethyl ether), "OXT-212" (3-ethyl-3-2-ethylhexyloxymethyloxetane), and "OXT-211" (3-ethyl-3-phenoxymethyloxetane) from Toagosei, as well as "Ethanacol EHO", "Ethanacol OXBP", "Ethanacol OXTP", and "Ethanacol OXMA" from Ube Industries.

[0064] The content of polymerizable compounds (or the total content if multiple polymerizable compounds are included) is preferably 1 to 30% by mass, more preferably 1 to 20% by mass, even more preferably 1 to 15% by mass, and particularly preferably 1 to 10% by mass, based on the total solid content of the composition.

[0065] (Resin) The composition may contain a resin. Examples of resins include (meth)acrylic resin, ene-thiol resin, polycarbonate resin, polyether resin, polyarylate resin, polysulfone resin, polyethersulfone resin, polyphenylene resin, polyarylene etherphosphine oxide resin, polyimide resin, polyamide-imide resin, polyolefin resin, cyclic olefin resin, polyester resin, styrene resin, and phenoxy resin. One of these resins may be used alone, or two or more may be used in combination.

[0066] One preferred embodiment of the resin is a resin having an acidic group, a basic group, or an amide group. Resins having an acidic group, a basic group, or an amide group readily function as a dispersant for dispersing magnetic particles. Examples of acidic groups include carboxyl groups, phosphoric acid groups, sulfo groups, and phenolic hydroxyl groups, with carboxyl groups being preferred. Examples of basic groups include amino groups (ammonia, primary amines, or secondary amines with one hydrogen atom removed) and imino groups. Among these, the resin is preferably one having a carboxyl group or an amide group.

[0067] If the resin has acidic groups, the acid value of the resin is preferably 10 to 500 mg KOH / g, and more preferably 30 to 400 mg KOH / g.

[0068] As the resin, it is preferable to use a resin that has improved dispersibility in the composition and a solubility in the solvent of 10 g / L or more, and more preferably a resin that has a solubility in the solvent of 20 g / L or more. The upper limit of the solubility of the resin in the solvent is preferably 2000 g / L or less, and more preferably 1000 g / L or less. The solubility of the resin in the solvent refers to the amount (g) of resin that dissolves in 1 L of solvent at 25°C.

[0069] The resin content is preferably 0.1 to 20% by mass, and more preferably 0.1 to 10% by mass, relative to the total solid content of the composition.

[0070] One preferred embodiment of the resin is a resin that functions as a dispersant for dispersing magnetic particles in the composition (hereinafter also referred to as "dispersion resin"). The effects of the present invention are further enhanced by using a dispersion resin.

[0071] Resin dispersion resins having repeating units including graft chains include resins having repeating units including graft chains (hereinafter also referred to as "Resin A"). However, Resin A can be used for purposes other than to function as a dispersant.

[0072] If the composition contains resin A, the content of resin A is preferably 0.1 to 20% by mass, and more preferably 0.1 to 10% by mass, relative to the total solid content of the composition, in order to achieve superior effects of the present invention.

[0073] ...In repeating units including graft chains, the steric repulsion effect increases as the length of the graft chain increases, improving the dispersibility of magnetic particles. On the other hand, if the graft chain is too long, the adsorption force to the magnetic particles decreases, and the dispersibility of magnetic particles tends to decrease. For this reason, the number of atoms excluding hydrogen atoms in the graft chain is preferably 40 to 10,000, more preferably 50 to 2,000, and even more preferably 60 to 500. Here, the graft chain refers to the length from the base of the main chain (atoms bonded to the main chain in groups branching off from the main chain) to the end of the groups branching off from the main chain.

[0074] Furthermore, the graft chain preferably contains a polymer structure, and examples of such polymer structures include poly(meth)acrylate structures (e.g., poly(meth)acrylic structures), polyester structures, polyurethane structures, polyurea structures, polyamide structures, and polyether structures. In order to improve the interaction between the graft chain and the solvent and thereby enhance the dispersibility of the magnetic particles, the graft chain preferably contains at least one selected from the group consisting of polyester structures, polyether structures, and poly(meth)acrylate structures, and more preferably contains at least one of polyester structures and polyether structures.

[0075] Resin A may be a resin obtained using a macromonomer containing graft chains (a monomer having a polymer structure that is bonded to the main chain to constitute a graft chain). There are no particular limitations on the macromonomer containing graft chains (a monomer having a polymer structure that is bonded to the main chain to constitute a graft chain), but macromonomers containing reactive double bond groups can be suitably used.

[0076] Resin A preferably contains at least one structure selected from the group consisting of methyl polyacrylate, polymethyl methacrylate, and cyclic or chain-like polyesters, more preferably contains at least one structure selected from the group consisting of methyl polyacrylate, polymethyl methacrylate, and chain-like polyesters, and even more preferably contains at least one structure selected from the group consisting of methyl polyacrylate structures, polymethyl methacrylate structures, polycaprolactone structures, and polyvalerolactone structures. Resin A may contain one of the above structures alone, or it may contain a plurality of these structures. Here, a polycaprolactone structure refers to a structure that contains a ring-opened ε-caprolactone structure as a repeating unit. A polyvalerolactone structure refers to a structure that contains a ring-opened δ-valerolactone structure as a repeating unit.

[0077] In resin A, the content of repeating units including graft chains is preferably 2 to 100% by mass, more preferably 2 to 90% by mass, and even more preferably 5 to 30% by mass, based on the total mass of resin A. The effects of the present invention are better when the repeating units including graft chains are included within this range.

[0078] ...Hydrophobic repeating units Furthermore, resin A may contain hydrophobic repeating units that are different from (i.e., do not correspond to) repeating units containing graft chains. However, in this specification, hydrophobic repeating units are repeating units that do not have acidic groups (e.g., carboxylic acid groups, sulfonic acid groups, phosphate groups, phenolic hydroxyl groups, etc.).

[0079] The hydrophobic repeating units are preferably (corresponding to) repeating units derived from compounds (monomers) with a ClogP value of 1.2 or higher, and more preferably from compounds with a ClogP value of 1.2 to 8. This allows the effects of the present invention to be more reliably expressed.

[0080] The ClogP value is calculated using the "CLOGP" program available from Daylight Chemical Information System, Inc. This program provides a "calculated logP" value calculated using the fragment approach by Hansch, Leo (see references below). The fragment approach is based on the chemical structure of a compound, dividing the chemical structure into substructures (fragments), and estimating the logP value of the compound by summing the logP contributions assigned to each fragment. Details are described in the following references. In this specification, we use ClogP values ​​calculated using the CLOGP v4.82 program. A. J. Leo, Comprehensive Medical Chemistry, Vol. 4, C. Hansch, P. G. Sammnens, J. B. Taylor and C. A. Ramsden, Eds. , p. 295, Pergamon Press, 1990 C. Hansch &A. J. Leo. Substituent Constants For Correlation Analysis in Chemistry and Biology. John Wiley & Sons. A. J. Leo. Calculating logPoct from structure. Chem. Rev. , 93, 1281-1306, 1993.

[0081] logP is the common logarithm of the partition coefficient P, and is a physical property that quantitatively represents how an organic compound is distributed in equilibrium between oil (generally 1-octanol) and water, and is expressed by the following formula: logP = log(Coil / Cwater). In the formula, Coil represents the molar concentration of the compound in the oil phase, and Cwater represents the molar concentration of the compound in the water phase. When the value of logP is large in the positive range around 0, oil solubility increases, and when the absolute value is large in the negative range, water solubility increases. There is a negative correlation between logP and the water solubility of organic compounds, and it is widely used as a parameter to estimate the hydrophilicity and hydrophobicity of organic compounds.

[0082] In resin A, the content of hydrophobic repeating units is preferably 5 to 90% by mass, and more preferably 20 to 80% by mass, relative to the total mass of resin A.

[0083] Resin A, which can form interactions with magnetic particles, may have functional groups that can form interactions with magnetic particles. It is preferable that resin A further contains repeating units that include functional groups that can form interactions with magnetic particles. Examples of functional groups that can form interactions with magnetic particles include acidic groups, basic groups, coordinating groups, and reactive functional groups. When resin A contains acidic groups, basic groups, coordinating groups, or reactive functional groups, it is preferable that it contains repeating units that include acidic groups, repeating units that include basic groups, repeating units that include coordinating groups, or repeating units that have reactive functional groups, respectively.

[0084] The repeating unit containing an alkali-soluble group as an acid group may be the same as or different from the repeating unit containing the graft chain described above, but the repeating unit containing an alkali-soluble group as an acid group is a different repeating unit from the hydrophobic repeating unit described above (i.e., it does not correspond to the hydrophobic repeating unit described above).

[0085] Examples of acidic groups that can form interactions with magnetic particles include carboxylic acid groups, sulfonic acid groups, phosphoric acid groups, and phenolic hydroxyl groups. At least one of carboxylic acid groups, sulfonic acid groups, phosphorus, and acidic groups is preferred, with carboxylic acid groups being more preferred. Carboxylic acid groups have good adsorption to magnetic particles and high dispersibility. In other words, it is preferable that resin A further contains repeating units that include at least one of carboxylic acid groups, sulfonic acid groups, and phosphoric acid groups.

[0086] Resin A may have one or more repeating units containing acid groups. If resin A contains repeating units containing acid groups, the content is preferably 5 to 80% by mass, and more preferably 10 to 60% by mass, based on the total mass of resin A.

[0087] Examples of basic groups that can form interactions with magnetic particles include primary amino groups, secondary amino groups, tertiary amino groups, heterocycles containing N atoms, and amide groups. The preferred basic group is the tertiary amino group because it has good adsorption to magnetic particles and high dispersibility. Resin A may contain one or more of these basic groups. If resin A contains repeating units containing basic groups, the content is preferably 0.01 to 50% by mass, and more preferably 0.01 to 30% by mass, based on the total mass of resin A.

[0088] Examples of coordinating groups and reactive functional groups that can form interactions with magnetic particles include acetylacetoxy groups, trialkoxysilyl groups, isocyanate groups, acid anhydrides, and acid chlorides. The preferred functional group is the acetylacetoxy group, which has good adsorption to magnetic particles and high dispersibility of magnetic particles. Resin A may have one or more of these groups. If resin A contains repeating units containing coordinating groups or repeating units containing reactive functional groups, the content of these is preferably 10 to 80% by mass, and more preferably 20 to 60% by mass, based on the total mass of resin A.

[0089] The ethylenically unsaturated resin A may contain ethylenically unsaturated groups. The ethylenically unsaturated groups are not particularly limited, but examples include (meth)acryloyl groups, vinyl groups, and styryl groups, with (meth)acryloyl groups being preferred. Among the resins A, it is preferable that the resin A contains repeating units with ethylenically unsaturated groups in the side chains, and more preferably that the resin A contains repeating units with ethylenically unsaturated groups in the side chains and derived from (meth)acrylate (hereinafter also referred to as "(meth)acrylic repeating units with ethylenically unsaturated groups in the side chains"). The (meth)acrylic repeating units with ethylenically unsaturated groups in the side chains can be obtained, for example, by adding an ethylenically unsaturated compound containing a glycidyl group or an alicyclic epoxy group to the carboxylic acid group in the resin A containing a (meth)acrylic repeating unit containing a carboxylic acid group. By reacting the ethylenically unsaturated group (glycidyl group or alicyclic epoxy group) introduced in this way, a (meth)acrylic repeating unit containing ethylenically unsaturated groups in the side chains can be obtained.

[0090] If resin A contains repeating units containing ethylenically unsaturated groups, the content thereof is preferably 10 to 80% by mass, and more preferably 15 to 40% by mass, relative to the total mass of resin A.

[0091] ...Other Repeating Units Furthermore, for the purpose of improving various properties such as film-forming ability, resin A may further have other repeating units having various functions, different from repeating units containing graft chains, hydrophobic repeating units, and repeating units containing functional groups that can form interactions with magnetic particles, provided that the effects of the present invention are not impaired. Examples of such other repeating units include repeating units derived from radical polymerizable compounds selected from acrylonitriles and methacrylonitriles. Resin A may use one or more of these other repeating units, and their content is preferably 0 to 80% by mass, and more preferably 10 to 60% by mass, based on the total mass of resin A.

[0092] ...Physical properties of resin A The acid value of resin A is not particularly limited, but for example, 0 to 400 mg KOH / g is preferred, 10 to 350 mg KOH / g is more preferred, 30 to 300 mg KOH / g is even more preferred, and 50 to 200 mg KOH / g is particularly preferred. If the acid value of resin A is 50 mg KOH / g or higher, the sedimentation stability of magnetic particles can be further improved.

[0093] In this specification, the acid value can be calculated, for example, from the average content of acid groups in the compound. Furthermore, a resin having a desired acid value can be obtained by changing the content of repeating units containing acid groups in the resin.

[0094] The weight-average molecular weight of resin A is not particularly limited, but for example, it is preferably 3,000 or more, more preferably 4,000 or more, even more preferably 5,000 or more, and particularly preferably 6,000 or more. As an upper limit, for example, it is preferably 300,000 or less, more preferably 200,000 or less, even more preferably 100,000 or less, and particularly preferably 50,000 or less. Resin A can be synthesized based on known methods.

[0095] - The alkali-soluble resin may contain an alkali-soluble resin. In this specification, "alkali-soluble resin" means a resin containing a group that promotes alkali solubility (alkali-soluble group, such as an acidic group such as a carboxylic acid group), and means a resin different from resin A which has already been described.

[0096] Examples of alkali-soluble resins include resins containing at least one alkali-soluble group in their molecule, such as polyhydroxystyrene resins, polysiloxane resins, (meth)acrylic resins, (meth)acrylamide resins, (meth)acrylic / (meth)acrylamide copolymers, and polyimide resins.

[0097] Specific examples of alkali-soluble resins include copolymers of unsaturated carboxylic acids and ethylenically unsaturated compounds. The unsaturated carboxylic acid is not particularly limited, but examples include monocarboxylic acids such as (meth)acrylic acid, crotonic acid, and vinylacetic acid; dicarboxylic acids such as itaconic acid, maleic acid, and fumaric acid, or their acid anhydrides; and polycarboxylic acid monoesters such as phthalic acid mono(2-(meth)acryloyloxyethyl); and so on.

[0098] Examples of copolymerizable ethylenically unsaturated compounds include methyl (meth)acrylate. Compounds described in paragraph 0027 of Japanese Patent Application Publication No. 2010-097210 and paragraphs 0036-0037 of Japanese Patent Application Publication No. 2015-068893 can also be used, and the above information is incorporated herein.

[0099] Furthermore, copolymerizable ethylenically unsaturated compounds containing ethylenically unsaturated groups in their side chains may also be used in combination. In other words, alkali-soluble resins may contain repeating units containing ethylenically unsaturated groups in their side chains. A (meth)acrylic acid group is preferred as the ethylenically unsaturated group contained in the side chain. A repeating unit containing an ethylenically unsaturated group in its side chain can be obtained, for example, by adding an ethylenically unsaturated compound containing a glycidyl group or an alicyclic epoxy group to a carboxylic acid group in a (meth)acrylic repeating unit containing a carboxylic acid group.

[0100] As the alkali-soluble resin, alkali-soluble resins containing curable groups are also preferred. Examples of the curable groups include ethylenically unsaturated groups (e.g., (meth)acryloyl groups, vinyl groups, and styryl groups), but are not limited to these. Among these, ethylenically unsaturated groups are preferred as curable groups, and (meth)acryloyl groups are more preferred, as polymerization can be controlled by radical reactions. As the alkali-soluble resin containing curable groups, alkali-soluble resins having curable groups in their side chains are preferred. Examples of alkali-soluble resins containing curable groups include Dianaal® NR series (manufactured by Mitsubishi Chemical Corporation), Photomer 6173 (COOH-containing polyethylene acrylic oligomer, manufactured by Diamond Shamrock Co., Ltd.), Viscoat R-264, KS Resist 106 (both manufactured by Osaka Organic Chemical Industry Co., Ltd.), Cyclomer P series (e.g., ACA230AA), Praxel CF200 series (both manufactured by Daicel Corporation), Ebecryl 3800 (manufactured by Daicel Ornex Corporation), and Acrycure RD-F8 (manufactured by Nippon Shokubai Co., Ltd.).

[0101] Polyimide precursors can also be used as alkali-soluble resins. A polyimide precursor refers to a resin obtained by an addition polymerization reaction between a compound containing an acid anhydride group and a diamine compound at 40 to 100°C.

[0102] The acid value of the alkali-soluble resin is not particularly limited, but is preferably 30 to 500 mg KOH / g, and more preferably 50 to 200 mg KOH / g or more.

[0103] If the composition contains an alkali-soluble resin, the content of the alkali-soluble resin is preferably 0.1 to 20% by mass, and more preferably 0.1 to 10% by mass, relative to the total solid content of the composition.

[0104] (Rheology Control Agent) The composition may contain a rheotropic agent. The rheotropic agent is a component that imparts thixotropic properties to the composition, exhibiting high viscosity at low shear force (shear rate) and low viscosity at high shear force (shear rate). The content of the rheotropic agent is preferably 0.01 to 10% by mass, more preferably 0.01 to 8% by mass, and even more preferably 0.01 to 5% by mass, based on the total solid content of the composition. Examples of rheotropic agents include organic rheotropic agents and inorganic rheotropic agents, with organic rheotropic agents being preferred.

[0105] • Organic Stabilizers Examples of organic stabilizers include compounds having one or more (preferably two or more) adsorption groups and further having steric repulsion structures. The adsorption groups interact with the surface of the magnetic particles to adsorb the organic stabilizer onto the surface of the magnetic particles. Examples of the adsorption groups include acid groups, basic groups, and amide groups. Examples of acid groups include carboxyl groups, phosphoric acid groups, sulfol groups, phenolic hydroxyl groups, and their acid anhydride groups (such as the acid anhydride group of a carboxyl group), and carboxyl groups are preferred in terms of superior effects of the present invention. Examples of basic groups include amino groups (ammonia, primary amines, or secondary amines with one hydrogen atom removed) and imino groups. Among these, carboxyl groups or amide groups are preferred as adsorption groups, and carboxyl groups are more preferred. The steric repulsion structural group has a sterically bulky structure, which introduces steric hindrance to the magnetic particles to which the organic oscillator is adsorbed, thereby maintaining an appropriate space between the magnetic particles. Examples of steric repulsion structural groups include chain groups, more preferably long-chain fatty acid groups, and even more preferably long-chain alkyl groups. The organic oscillator may also preferably have hydrogen-bonding units. These hydrogen-bonding units are substructures that function to construct a hydrogen-bonding network between organic oscillators and between organic oscillators and other components. The organic oscillator contributing to the formation of this network may or may not be adsorbed on the surface of the magnetic particles. The hydrogen-bonding units may or may not be the same as the adsorbing groups described above. If the hydrogen-bonding units are the same as the adsorbing groups described above, a portion of the adsorbing groups bond to the surface of the magnetic particles, while the other portion functions as the hydrogen-bonding unit. Carboxylate groups or amide groups are preferred as the hydrogen-bonding units. Carboxylate groups as hydrogen bonding units are preferred because they are easily incorporated into the curing reaction of the binder's curable groups (e.g., epoxy groups or oxetanyl groups) when producing magnetic materials, while amide groups are preferred because they provide better long-term stability of the composition.

[0106] When the organic vibrator is a resin, the resin organic vibrator may have repeating units containing graft chains that can be contained in the dispersant described above, or it may not have substantially any. When the resin organic vibrator does not substantially have repeating units containing graft chains that can be contained in the dispersant described above, the content of the repeating units containing graft chains described above relative to the total mass of the resin organic vibrator is preferably less than 2% by mass, more preferably 1% by mass or less, and even more preferably less than 0.1% by mass. The lower limit is 0% by mass or more.

[0107] The organic stabilizer is preferably one or more selected from the group consisting of polycarboxylic acids (compounds having two or more carboxyl groups), polyanhydrides (compounds having two or more acid anhydride groups consisting of carboxyl groups), and amide waxes. These may be resins or other materials. Furthermore, these may correspond to the flocculation control agents and / or flocculation dispersants described later.

[0108] Examples of organic stabilizers include modified urea, urea-modified polyamides, fatty acid amides, polyurethanes, polyamide amides, high-molecular-weight urea derivatives, and their salts (carboxylate salts, etc.). Modified urea is a reaction product of an isocyanate monomer or its adduct with an organic amine. Modified urea is modified with polyoxyalkylene polyols (polyoxyethylene polyols, polyoxypropylene polyols, etc.) and / or alkyd chains. Urea-modified polyamides are, for example, compounds containing urea bonds and compounds to which a medium-polarity group or a low-polarity group has been introduced at the terminal. Examples of medium-polarity or low-polarity groups include polyoxyalkylene polyols (polyoxyethylene polyols, polyoxypropylene polyols, etc.) and alkyd chains. Fatty acid amides are compounds having a long-chain fatty acid group and an amide group in their molecule. These may be resins or other materials. Furthermore, these may also fall under the categories of flocculation control agents and / or flocculation dispersants, as described later.

[0109] The molecular weight of the organic stabilizer (or weight-average molecular weight if it has a molecular weight distribution) is preferably in the range of 200 to 50,000. If the organic stabilizer has an acid value, the acid value is preferably 5 to 400 mg KOH / g. If the organic stabilizer has an amine acid value, the amine value is preferably 5 to 300 mg KOH / g.

[0110] ...As organic flocculation control agents, flocculation control agents can also be mentioned. Flocculation control agents may be resins or other materials. Flocculation control agents have the function of binding to relatively dense aggregates such as magnetic particles, and further dispersing components such as binders in the composition, thereby creating bulky aggregates. When a composition contains a flocculation control agent, the hard cake formation of magnetic particles in the composition is suppressed, and bulkier aggregates are formed, which can improve redispersibility.

[0111] Examples of flocculation control agents include cellulose derivatives. Examples of cellulose derivatives include carboxymethylcellulose, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, hydroxypropylethylcellulose, and salts thereof.

[0112] ...As organic flocculants and dispersants, flocculants and dispersants can also be used. Flocculants and dispersants may be resins or other materials. Flocculants and dispersants adsorb onto the surface of magnetic particles, causing the magnetic particles to separate from each other, and maintaining a certain distance between the magnetic particles through interactions between dispersants, thereby preventing the magnetic particles from directly aggregating. As a result, aggregation of magnetic particles is suppressed, and even if aggregates are formed, they are relatively low-density aggregates. Furthermore, components such as binders can be dispersed in the composition to create bulky aggregates, which can improve redispersibility.

[0113] As a flocculant and dispersant, alkylol ammonium salts of polybasic acids are preferred. Polybasic acids only need to have two or more acidic groups; for example, acidic polymers containing repeating units with acidic groups (e.g., polyacrylic acid, polymethacrylic acid, polyvinyl sulfonic acid, and polyphosphate) are examples. Other polybasic acids include polymers obtained by polymerizing unsaturated fatty acids such as crotonic acid. Alkyloll ammonium salts of polybasic acids are obtained by reacting these polybasic acids with alkylol ammonium. Salts obtained by such reactions typically contain the following substructure: -C(=O)-N(-R １ ) (-R ２ -OH) Here, R １ is an alkyl group, R ２ This is an alkylene group. As the alkylol ammonium salt of a polybasic acid, a polymer containing multiple of the above substructures is preferred. When the alkylol ammonium salt of a polybasic acid is a polymer, the weight-average molecular weight is preferably 1,000 to 100,000, and more preferably 5,000 to 20,000. The polymer of the alkylol ammonium salt of a polybasic acid can bond to the surface of magnetic particles and form hydrogen bonds with other flocculant dispersant molecules, allowing the polymer's main chain structure to penetrate between magnetic particles and separate them.

[0114] One preferred embodiment of the flocculant and dispersant is an amide wax, which is a condensate product obtained by dehydration condensation of (a) saturated aliphatic monocarboxylic acids and hydroxyl group-containing aliphatic monocarboxylic acids, (b) at least one of polybasic acids, and (c) at least one of diamines and tetraamines. It is preferable that (a) to (c) are used in a molar ratio of (a):(b):(c) = 1 to 3:0 to 5:1 to 6.

[0115] Saturated aliphatic monocarboxylic acids are preferably those having 12 to 22 carbon atoms. Specifically, examples include lauric acid, myristic acid, pentadecyl acid, palmitic acid, margaric acid, stearic acid, nonadecanoic acid, arachidic acid, and behenic acid. Hydroxy group-containing aliphatic monocarboxylic acids are preferably those having 12 to 22 carbon atoms. Specifically, examples include 12-hydroxystearic acid and dihydroxystearic acid. These saturated aliphatic monocarboxylic acids and hydroxy group-containing aliphatic monocarboxylic acids may be used individually or in combination.

[0116] The polybasic acids are preferably dibasic or greater carboxylic acids having 2 to 12 carbon atoms, and more preferably dicarboxylic acids. Examples of such dicarboxylic acids include aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,10-decanedicarboxylic acid, and 1,12-dodecanedicarboxylic acid; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid; and alicyclic dicarboxylic acids such as 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and cyclohexylsuccinic acid. These polybasic acids may be used individually or in combination.

[0117] Diamines are preferably those having 2 to 14 carbon atoms. Specifically, examples include ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, hexamethylenediamine, metaxylenediamine, tolylenediamine, paraxylenediamine, phenylenediamine, isophoronediamine, 1,10-decanediamine, 1,12-dodecanediamine, 4,4-diaminodicyclohexylmethane, and 4,4-diaminodiphenylmethane. Tetraamines are preferably those having 2 to 14 carbon atoms. Specifically, examples include butane-1,1,4,4-tetraamine and pyrimidine-2,4,5,6-tetraamine. These diamines and tetraamines may be used individually or in combination.

[0118] The amounts of diamines and tetraamines are adjusted according to the number of moles of saturated aliphatic monocarboxylic acid or hydroxyl group-containing aliphatic monocarboxylic acid and the number of moles of polybasic acids, so that the total number of carboxyl groups and the total number of amino groups are equivalent. For example, if there are 2 moles of aliphatic monocarboxylic acid and n moles of aliphatic dicarboxylic acid (n = 0 to 5), then if the amount of diamines is (n + 1) moles, the acid and amine will be equivalent.

[0119] This amide wax may be obtained as a mixture of multiple compounds having different molecular weights. The amide wax is preferably a compound represented by the following chemical formula (I). Note that the amide wax may be a single compound or a mixture. A-C-(B-C) ｍ -A...(I) In formula (I), A is a dehydrated group residue of a saturated aliphatic monocarboxylic acid and / or a hydroxyl group-containing saturated aliphatic monocarboxylic acid, B is a dehydrated group residue of a polybasic acid, C is a dehydrogenated residue of a diamine and / or a tetraamine, and m is 0 ≤ m ≤ 5.

[0120] One preferred embodiment of the flocculant / dispersant is a compound represented by the following formula (II).

[0121]

[0122] In formula (II), R １ R represents a monovalent linear aliphatic hydrocarbon group having 10 to 25 carbon atoms. ２ and R ３ Each of these independently represents a divalent aliphatic hydrocarbon group having 2, 4, 6, or 8 carbon atoms, a divalent alicyclic hydrocarbon group having 6 carbon atoms, or a divalent aromatic hydrocarbon group, R ４ R represents a divalent aliphatic hydrocarbon group having 1 to 8 carbon atoms. ５ and R ６ Each of these independently represents a monovalent aliphatic hydrocarbon group having 1 to 3 carbon atoms, or a hydroxyalkyl ether group. In formula (II), L １ ~L ３ Each of these independently represents an amide bond, L １ and L ３ If it is -CONH-, L ２ is -NHCO-, L１ and L ３ If L is -NHCO-, ２ It is -CONH-.

[0123] R １ R is a monovalent linear aliphatic hydrocarbon group having 10 to 25 carbon atoms, and examples include linear alkyl groups such as decyl, lauryl, myristyl, pentadecyl, stearyl, palmityl, nonadecyl, eicosyl, and behenyl groups; linear alkenyl groups such as decenyl, pentadecenyl, oleyl, and eicocenyl groups; and linear alkynyl groups such as pentadecinyl, octadecinyl, and nonadecinyl groups. Among these, R １ The linear aliphatic hydrocarbon group is preferably a monovalent linear aliphatic hydrocarbon group having 14 to 25 carbon atoms, and more preferably a monovalent linear aliphatic hydrocarbon group having 18 to 21 carbon atoms. The linear aliphatic hydrocarbon group is preferably an alkyl group.

[0124] R ２ and R ３ Examples of divalent aliphatic hydrocarbon groups having 2, 4, 6, or 8 carbon atoms include ethylene, n-butylene, n-hexylene, and n-octylene groups. ２ and R ３ Examples of C6 divalent alicyclic hydrocarbon groups in this context include 1,4-cyclohexylene, 1,3-cyclohexylene, and 1,2-cyclohexylene. ２ and R ３ Examples of divalent aromatic hydrocarbon groups in this context include arylene groups having 6 to 10 carbon atoms, such as 1,4-phenylene groups, 1,3-phenylene groups, and 1,2-phenylene groups.

[0125] Among them, R ２ and R ３ In terms of excellent thickening effect, divalent aliphatic hydrocarbon groups having 2, 4, 6, or 8 carbon atoms are preferred, more preferably divalent aliphatic hydrocarbon groups having 2, 4, or 6 carbon atoms, even more preferably divalent aliphatic hydrocarbon groups having 2 or 4 carbon atoms, and most preferably divalent aliphatic hydrocarbon groups having 2 carbon atoms. Linear alkylene groups are preferred for the divalent aliphatic hydrocarbon groups.

[0126] R ４ R represents a divalent aliphatic hydrocarbon group having 1 to 8 carbon atoms, and among these, linear or branched alkylene groups are preferred, with linear alkylene groups being more preferred, due to their excellent thickening effect. ４ The number of carbon atoms in the divalent aliphatic hydrocarbon group in is 1 to 8, and in terms of excellent thickening effect, 1 to 7 is preferred, 3 to 7 is more preferred, 3 to 6 is even more preferred, and 3 to 5 is particularly preferred. Therefore, R ４ The alkylene group is preferably a linear or branched alkylene group having 1 to 8 carbon atoms, more preferably a linear alkylene group having 1 to 7 carbon atoms, even more preferably a linear alkylene group having 3 to 7 carbon atoms, particularly preferably a linear alkylene group having 3 to 6 carbon atoms, and most preferably a linear alkylene group having 3 to 5 carbon atoms.

[0127] R ５ and R ６ Examples of monovalent aliphatic hydrocarbon groups having 1 to 3 carbon atoms include linear or branched alkyl groups having 1 to 3 carbon atoms such as methyl, ethyl, propyl, and isopropyl groups; linear or branched alkenyl groups having 2 to 3 carbon atoms such as vinyl, 1-methylvinyl, and 2-propenyl groups; and linear or branched alkynyl groups having 2 to 3 carbon atoms such as ethynyl and propynyl groups.

[0128] R ５ and R ６ Examples of hydroxyalkyl ether groups in this context include mono- or di(hydroxy)C groups such as 2-hydroxyethoxy, 2-hydroxypropoxy, and 2,3-dihydroxypropoxy. １－３ Alkyl ether groups are one example.

[0129] Among them, R ５ and R ６ Each of these groups is preferably a monovalent aliphatic hydrocarbon group having 1 to 3 carbon atoms, more preferably a linear or branched alkyl group having 1 to 3 carbon atoms, even more preferably a linear alkyl group having 1 to 3 carbon atoms, and particularly preferably a methyl group.

[0130] As for the compound represented by formula (II), the compounds represented by the following formulas (II-1) to (II-9) are preferred.

[0131]

[0132] Examples of flocculants and dispersants include ANTI-TERRA-203, 204, 206, and 250 (all trade names, manufactured by BYK Corporation); ANTI-TERRA-U (trade name, manufactured by BYK Corporation); DISPER BYK-102, 180, and 191 (all trade names, manufactured by BYK Corporation); BYK-P105 (trade name, manufactured by BYK Corporation); TEGO Disper 630 and 700 (both trade names, manufactured by Evonik Degussa Japan Co., Ltd.); TALENE VA-705B (trade name, manufactured by Kyoeisha Chemical Co., Ltd.); and FLONON RCM-100, RCM-300TL, and RCM-230AF (trade names, manufactured by Kyoeisha Chemical Co., Ltd., amide wax).

[0133] Inorganic oscillating agents: Examples of inorganic oscillating agents include bentonite, silica, calcium carbonate, and smectite.

[0134] (Curing agent) The composition may contain a curing agent. Examples of curing agents include acid anhydride-based curing agents, amine-based curing agents, phenol-based curing agents, naphthol-based curing agents, active ester-based curing agents, benzoxazine-based curing agents, cyanate ester-based curing agents, mercapto-based curing agents, and carbodiimide-based curing agents. Among these, acid anhydride-based curing agents or amine-based curing agents are preferred.

[0135] Examples of acid anhydride-based curing agents include curing agents having one or more acid anhydride groups in one molecule. Specific examples of acid anhydride-based curing agents include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexen-1,2-dicarboxylic acid anhydride, trimellitic anhydride, pyromellitic anhydride, and bensophenone tetracarboxylic acid di Examples include anhydrides, biphenyltetracarboxylic acid dianhydride, naphthalenetetracarboxylic acid dianhydride, oxydiphthalic acid dianhydride, 3,3'-4,4'-diphenylsulfontetracarboxylic acid dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-C]furan-1,3-dione, ethylene glycol bis(anhydrotrimellitate), and polymer-type acid anhydrides such as styrene-maleic acid resin obtained by copolymerizing styrene and maleic acid. Commercially available acid anhydride-based curing agents include "HNA-100," "MH-700," "MTA-15," "DDSA," "HF-08," and "OSA" from Shin Nippon Rika Co., Ltd., "YH306" and "YH307" from Mitsubishi Chemical Corporation, "H-TMAn" from Mitsubishi Gas Chemical Corporation, and "HN-2200," "HN-2000," "HN-5500," and "MHAC-P" from Hitachi Chemical Co., Ltd.

[0136] Examples of amine-based curing agents include aliphatic amine-based curing agents, aromatic amine-based curing agents, and amine adduct-based curing agents.

[0137] When the composition contains a curing agent, the ratio of the polymerizable compound to the curing agent is preferably such that the equivalent ratio of epoxy groups and oxetanyl groups contained in the polymerizable compound to the reactive groups (active hydrogen groups such as hydroxyl groups in the curing agent) ("total number of epoxy groups and oxetanyl groups" / "number of reactive groups") is 30 / 70 to 70 / 30, more preferably 40 / 60 to 60 / 40, and even more preferably 45 / 55 to 55 / 45. The curing agent may be used alone or in combination of two or more types. The curing agent content is preferably 0.001 to 5% by mass, and more preferably 0.01 to 3% by mass, relative to the total solid content of the composition.

[0138] (Solvent) The composition may contain a solvent. An organic solvent is preferred as the solvent. The type of organic solvent is not particularly limited, and examples include ester solvents (preferably acetate solvents), ketone solvents, alcohol solvents, amide solvents, ether solvents, and hydrocarbon solvents. One organic solvent may be used alone, or two or more may be used together.

[0139] The lower limit of the boiling point of the organic solvent is preferably 55°C or higher, more preferably 80°C or higher, and even more preferably 100°C or higher. There is no particular limit to the upper limit of the boiling point of the organic solvent, but it is preferably 400°C or lower, and more preferably 250°C or lower.

[0140] Examples of organic solvents include acetone (boiling point 56°C), methyl ethyl ketone (boiling point 79.6°C), ethanol (boiling point 78.4°C), cyclohexane (boiling point 80.8°C), ethyl acetate (boiling point 77.1°C), and ethylene dichloride (boiling point 83°C).5°C), tetrahydrofuran (boiling point 66°C), cyclohexanone (boiling point 155.6°C), toluene (boiling point 110°C), ethylene glycol monomethyl ether (boiling point 124°C), ethylene glycol monoethyl ether (boiling point 135°C), ethylene glycol dimethyl ether (boiling point 84°C), propylene glycol monomethyl ether (boiling point 120°C), propylene glycol monoethyl ether (boiling point 132°C), acetylacetone (boiling point 140°C), cyclopentanone (boiling point 131°C), ethylene glycol Recall monomethyl ether acetate (boiling point 144.5°C), ethylene glycol ethyl ether acetate (boiling point 145°C), ethylene glycol monoisopropyl ether (boiling point 141°C), diacetone alcohol (boiling point 166°C), ethylene glycol monobutyl ether acetate (boiling point 192°C), 1,4-butanediol diacetate ("1,4-BDDA", boiling point 232°C), 1,6-hexanediol diacetate ("1,6-HDDA", boiling point 260°C), 1,3-butylene glyco Diacetate ("1,3-BGDA", boiling point 232°C), propylene glycol diacetate ("PGDA", boiling point 190°C), glycerol triacetic acid (boiling point 260°C), 3-methoxy-1-propanol (boiling point 150°C), 3-methoxy-1-butanol (boiling point 161°C), diethylene glycol monomethyl ether (boiling point 194°C), diethylene glycol monoethyl ether (boiling point 202°C), diethylene glycol dimethyl ether (boiling point 162°C), diethylene glycol diethyl ether (boiling point Examples include propylene glycol monomethyl ether acetate ("PGMEA", boiling point 146°C), propylene glycol monoethyl ether acetate (boiling point 146°C), N,N-dimethylformamide (boiling point 153°C), dimethyl sulfoxide (boiling point 189°C), γ-butyrolactone (boiling point 204°C), ethyl acetate (boiling point 77.1°C), butyl acetate (boiling point 126°C), methyl lactate (boiling point 144°C), N-methyl-2-pyrrolidone (boiling point 202°C), and ethyl lactate (boiling point 154°C).

[0141] The solvent content is preferably 1 to 40% by mass, more preferably 2 to 30% by mass, even more preferably 3 to 20% by mass, and particularly preferably 3 to 15% by mass, based on the total mass of the composition.

[0142] (Other optional components) The composition may further contain other optional components in addition to those described above. Examples include curing accelerators, sensitizers, co-sensitizers, plasticizers, diluents, oil-sensing agents, fillers, surfactants, adhesion aids (e.g., silane coupling agents), and rubber components. Furthermore, known additives such as auxiliary agents (e.g., defoamers, flame retardants, leveling agents, peel accelerators, antioxidants, fragrances, surface tension modifiers, and chain transfer agents) may be added as needed.

[0143] (Physical properties of the composition) The composition is preferably in paste form. The viscosity of the composition at 23°C is preferably 1 to 10,000 Pa·s, more preferably 1 to 5,000 Pa·s, and even more preferably 1 to 1,000 Pa·s, when the rotational speed (shear rate) of the rheometer is 0.1 (1 / s), from the viewpoint of superior settling stability of the magnetic particles. Here, the viscosity of the composition at 23°C can be measured using MCR-102 (manufactured by Anton Paar).

[0144] (Method for Manufacturing the Composition) The composition can be prepared by mixing magnetic particles with other optional components to be incorporated into the composition using a known mixing method (for example, a mixing method using a stirrer, kneader, homogenizer, high-pressure emulsifier, wet grinder, or wet disperser). When manufacturing the composition, each component may be incorporated all at once, or each component may be dissolved or dispersed in a solvent and then incorporated sequentially. Furthermore, there are no particular restrictions on the order of addition or working conditions when incorporating the components.

[0145] <Method for Manufacturing a Magnetic Substrate> An example of a method for manufacturing a magnetic substrate is a method that includes the following steps 1 and 2 (preferably steps 1 to 3). Step 1: A step of applying a composition to the surface of a substrate having through-holes that penetrate in the thickness direction by known coating methods such as slit coating, inkjet coating, rotary coating, casting coating, roll coating, and screen printing, thereby filling the through-holes with the composition. Step 2: A step of curing the composition on the substrate after step 1 by heating. Step 3: A step of removing any unwanted portions of the magnetic material that protrude from the substrate surface by physical polishing after step 2, or while step 2 is being carried out, to create a flat surface.

[0146] The filling step in step 1 may be carried out in either an atmospheric pressure environment or a reduced pressure environment. Among the filling steps in step 1, a step of applying the composition by screen printing in a reduced pressure environment (preferably a vacuum) to fill the through-holes of the substrate with the composition is preferred.

[0147] In the heat treatment in step 2, it is preferable to perform the process multiple times by changing the heating conditions such as heating temperature and heating time in order to adjust the Vickers hardness of the formed magnetic material to a predetermined range. The heating temperature is preferably 80 to 240°C, more preferably 100 to 220°C, and even more preferably 100 to 200°C. The heating time is preferably 30 to 240 minutes, and more preferably 30 to 180 minutes. The heat treatment can be carried out continuously or in batches using heating means such as a hot plate, a convection oven (hot air circulation type dryer), and a high-frequency heating machine. As for the heating conditions in step 2, it is preferable to perform heating conditions 1, in which the heating temperature is 100 to 150°C and the heating time is 30 to 240 minutes, and heating conditions 2, in which the heating temperature is 180 to 220°C and the heating time is 75 to 240 minutes, in stages, as this makes it easier to adjust the Vickers hardness of the magnetic material to a predetermined range. Furthermore, when performing the heat treatment under heating condition 1, the heating temperature and heating time settings may be changed and the heat treatment may be performed multiple times. For example, the first heating may be performed at a heating temperature of 130°C for a heating time of 30 minutes, and then the second heating may be performed at a heating temperature of 145°C for a heating time of 30 minutes. When performing the heat treatment under heating condition 1 with multiple heating conditions, it is preferable that the total heating time is between 30 and 240 minutes. Furthermore, when performing the heat treatment under heating condition 2, the heating temperature and heating time settings may be changed and the heat treatment may be performed multiple times. When performing the heat treatment under heating condition 2 with multiple heating conditions, it is preferable that the total heating time is between 75 and 240 minutes.

[0148] Step 3 is a process (grinding process) in which unwanted portions of the magnetic material that protrude from the substrate surface are removed by physical polishing to create a flat surface. The grinding process can be carried out by known methods. It is preferable that Step 3 is carried out after Step 2, or while Step 2 is being carried out. When Step 3 is carried out while Step 2 is being carried out, it is preferable that, for example, Step 3 is carried out between the above-described heating conditions 1 and heating conditions 2.

[0149] [Substrate with Conductor] The substrate with a conductor of the present invention is a substrate with a conductor comprising a substrate with a magnetic material and a conductor, wherein the magnetic material of the substrate has through holes, and the conductor is arranged on the side wall of the through holes of the magnetic material.

[0150] The configuration of the substrate with a conductor portion will be described below with reference to the drawings. Figure 2 is a schematic diagram showing an example of an embodiment of the substrate with a conductor portion, and Figure 3 is a schematic diagram of a cross-section of the substrate 20 with a conductor portion in a direction perpendicular to the thickness direction Dt of Figure 2. The substrate 20 with a conductor portion shown in Figures 2 and 3 has a substrate 11, a plurality of through holes 13 provided in the substrate 11, and magnetic material portions 21 filled in the through holes 13. The through holes 13 are through holes that penetrate the substrate 11 in the thickness direction Dt. The magnetic material portion 21 has through holes 23 that penetrate in the thickness direction Dt, and the conductor portion 25 is arranged on the wall surface of the through holes 23 of the magnetic material portion 21 (the wall surface formed by the outer edge 23E of the through holes 23 of the magnetic material portion 21 (see Figure 3)). In other words, the conductor portion 25 is arranged to extend along the side wall of the magnetic material portion 21. Note that Figures 2 and 3 are schematic diagrams, and the shape and positional relationships may not necessarily match those of the actual product. In a substrate with a conductive part, the placement position and shape of the magnetic part on the substrate are arbitrary and not particularly limited.

[0151] The shape of the through-hole 23 in the magnetic material portion 21 in a cross-section perpendicular to the thickness direction Dt of the substrate 20 with the conductive portion (the shape of the opening of the through-hole 23) is not particularly limited, but it is preferably circular. In Figures 2 and 3, the shape of the opening of the through-hole is circular. The position of the through-hole 23 in the magnetic material portion 21 is not particularly limited, but as shown in Figures 2 and 3, if the shape of the through-hole 13 in the substrate 11 and the through-hole 23 in the magnetic material portion 21 are circular in a cross-section perpendicular to the thickness direction Dt of the substrate 11, it is preferable to position them so as to be concentric with the through-hole 13 in the substrate 11.

[0152] As shown in Figure 3, in the substrate 20 with a conductor portion, the ratio of the shortest in-plane distance L2 of the substrate from the outer edge 13E of the through hole 13 of the substrate 11 (which also corresponds to the outer edge of the magnetic portion 21 in the substrate 20 with a conductor portion) to the thickness L1 of the conductor portion 25 (shortest distance L2 / thickness L1) is preferably 5 to 20, and more preferably 7 to 15.

[0153] The metal included in the conductor is not particularly limited, and examples include known metals. Specifically, examples include metals such as copper, chromium, lead, nickel, gold, silver, tin, and zinc, as well as alloys of these metals, with copper or its alloys being preferred. Furthermore, the conductor is preferably formed by a plating method, and the thickness L1 of the conductor is preferably, for example, 10 to 20 μm.

[0154] [Method for Manufacturing a Substrate with Conductor Parts] An example of a method for manufacturing a substrate with a conductor part is a method including the following steps I to III. Step I: A step in which a magnetic part containing magnetic particles and having a Vickers hardness of 56 to 160 HV is formed in the through-holes of a substrate having through-holes. Step II: A step in which through-holes are formed in the magnetic part. Step III: A step in which a conductor part is formed on the side wall of the through-holes in the magnetic part.

[0155] Step I is as described in detail in the upper section as a method for manufacturing a substrate with a magnetic material.

[0156] Step II is the process of forming through holes in the magnetic material, which is typically a drilling process. The drilling process can be carried out by known methods.

[0157] Step III is the step of forming a conductive portion on the side wall of the through hole in the magnetic material. The conductive portion is preferably formed by a plating process. Examples of plating methods include electroless plating and electrolytic plating. When the plating process is carried out, a conductive portion (plating layer) is formed on the side wall of the through hole in the magnetic material. Examples of metals to be included in the conductive portion include known metals. Specifically, these include metals such as copper, chromium, lead, nickel, gold, silver, tin, and zinc, as well as alloys of these metals. In particular, when the conductive portion is formed by a plating process, the metal included in the conductive portion preferably contains copper or an alloy thereof, and more preferably contains copper as the main component.

[0158] [Electronic Components] The electronic components of the present invention include the above-described substrate with a conductive part. That is, the electronic components of the present invention may include the above-described substrate with a conductive part as part of the component. Examples of electronic components include circuit boards including embedded inductors.

[0159] The present invention will be described in more detail below based on the following examples. The materials, amounts used, proportions, processing content, and processing procedures shown in the following examples can be modified as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the following examples. In the following, unless otherwise specified, "parts" and "%" are based on mass.

[0160] [Various components contained in the composition] The various components used in the preparation of the composition are listed below.

[0161] [Magnetic Particles] ・M-1: Ni-Zn-Co ferrite (Classified by sieving to remove coarse particles. D50: 32 μm, spherical) ・M-2: Ni-Zn ferrite (D50: 60 μm, spherical) ・M-3: Mn-based ferrite (D50: 3.7 μm) ・M-4: Mn-based ferrite (D50: 0.1 μm) ・M-5: Fe-Co-based ferrite (D50: 1 μm)

[0162] <Measurement of D50 of Magnetic Particles> The D50 of each magnetic particle used as a raw material as described above is determined based on the particle size distribution curve, which represents the volume-based frequency distribution of magnetic particles, obtained using a laser diffraction scattering particle size distribution analyzer (for example, the "LA960N" product manufactured by Horiba, Ltd.).

[0163] [Epoxy Compounds] ・E-1: Denacol EX-314 (Glycerol polyglycidyl ether, manufactured by Nagase ChemteX Corporation) ・E-2: Denacol EX-512 (Polyglycerol polyglycidyl ether, manufactured by Nagase ChemteX Corporation) ・E-3: Denacol EX-614 (Sorbitol polyglycidyl ether, manufactured by Nagase ChemteX Corporation) ・E-4: N,N-Diglycidyl-4-Glycidyloxyaniline (manufactured by Sigma-Aldrich) ・E-5: 4,4'-Methylenebis(N,N-Diglycidylaniline) (manufactured by Tokyo Chemical Industry Co., Ltd.) ・E-6: jER890 (Bisphenol F type liquid epoxy resin, manufactured by Mitsubishi Chemical Corporation) ・E-7: YED216 (Diglycidyl 1,2-Cyclohexanedicarboxylic acid, manufactured by Mitsubishi Chemical Corporation) • E-8: 3-methyl-3-phenylglycidate ethyl (manufactured by Fujifilm Wako Pure Chemical Corporation)

[0164] [Resin] ・B-1: Compound with the following structure (The numerical value attached to each repeating unit constituting the main chain represents the content (mass %) relative to the total number of repeating units. The numerical value attached to the repeating units constituting the side chain represents the average number of additions.)

[0165]

[0166] • B-2: Compounds with the following structure (The numbers attached to each repeating unit constituting the main chain represent the content (mass %) relative to the total number of repeating units. The numbers attached to the repeating units constituting the side chain represent the average number of additions.)

[0167]

[0168] • B-3: Compounds with the following structure (The numbers attached to each repeating unit constituting the main chain represent the content (mass %) relative to the total number of repeating units. The numbers attached to the repeating units constituting the side chain represent the average number of additions.)

[0169]

[0170] • B-4: Compounds with the following structure (The numerical values ​​attached to each repeating unit constituting the main chain represent the content (mass %) relative to the total number of repeating units.)

[0171]

[0172] • B-5: Hinoact T6000 (manufactured by Kawaken Fine Chemical Co., Ltd.)

[0173] [Rheology control agents] ・C-1: Product name "Talen VA705B" (high-grade fatty acid amide, manufactured by Kyoeisha Chemical Co., Ltd.) ・C-2: Flownon RCM-100 (fatty acid ester / aromatic ester, manufactured by Kyoeisha Chemical Co., Ltd.)

[0174] [Hardening agent] ・D-1: 4,4'-diaminodiphenylsulfone (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) ・D-2: Ricacid MTA-15 (manufactured by Shin Nippon Rika Co., Ltd.)

[0175] • F-1: Glycerol triacetic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) • F-2: 1,4-butanediol diacetate (1,4-BDDA (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.))

[0176] [Preparation of the magnetic substrate of Example 1] [Preparation of Composition 1] Composition 1 is prepared by mixing and stirring the various components in the components and composition (mass%) shown in Table 1.

[0177] [Fabrication of Substrate with Magnetic Material] The substrate 1 with magnetic material of Example 1 is fabricated according to the following procedure. Multiple through holes (vias) with a diameter of 1000 μm are formed in a 1.6 mm thick FR-4 substrate using a drill. The shape of the opening of the formed through holes is circular. The spacing between the through holes is 2000 μm, and 5 rows × 10 holes (50 through holes) are formed as one set. Next, the area below the through holes formed in the substrate is depressurized from the bottom (back) side of the substrate, and composition 1 is applied to the substrate surface from the top (front) side of the substrate by screen printing, thereby filling the through holes with magnetic particles. Next, the composition embedded in the through holes is heat-cured (pre-cured) by performing a first heat treatment at a temperature of 130°C for 30 minutes and a second heat treatment at a temperature of 145°C for 30 minutes. After that, the magnetic material layer that has protruded from the top and bottom surfaces of the substrate is polished off to flatten the surface. Subsequently, a third heat treatment is performed at 190°C for 90 minutes to fully heat-cur the embedded magnetic material and form the magnetic part.

[0178] <Measurement of Vickers hardness of the magnetic material> The Vickers hardness (HV) of the magnetic material of the substrate 1 with the magnetic material attached is measured according to the following procedure. Using a Vickers hardness tester (manufactured by Fischer Instruments), 50 measurements are taken under the condition of a load of 1000 mN / 10 seconds, and the average value is taken as the Vickers hardness of the magnetic material, and evaluation is performed based on the following classifications.

[0179] (Vickers hardness (HV)) A: 85 or higher, 160 or lower B: 70 or higher, less than 85 C: 56 or higher, less than 70 D: Less than 56 E: Over 160

[0180] [Evaluation] <Evaluation of through-hole formation capability by drilling> A 600 μm diameter micro-drill is used to form through-holes in the magnetic material portion of the substrate 1 with a magnetic material portion, penetrating in the thickness direction of the substrate. The shape of the opening of the formed through-holes is circular.

[0181] <Evaluation of the number of particles detached and cracks> A substrate 1 with a magnetic material attached, in which through holes have been formed in the magnetic material by drilling, is embedded in epoxy resin and cured. Next, the substrate 1 with the magnetic material attached is cut parallel to the thickness direction of the substrate 1 using a dicing blade. The dicing blade is adjusted so that it cuts at the center of the through hole in the magnetic material. Next, the cut surface is polished with a grinder and then mirror-finished with a compound. Then, the number of magnetic particles that have detached from the side wall surface of the through hole in the magnetic material attached to the substrate 1 (number of recesses formed on the side wall surface) and the number of cracks that have occurred on the side wall surface are observed using an optical microscope and evaluated according to the following classification. A rating of "B" or higher is preferable, and an "A" rating is more preferable. A: No particles detached B: 1 particle detached C: 2 or more particles detached D: Cracks (fissures) occur in the magnetic material

[0182] [Preparation of Magnetic Substrates for Examples 2-32 and Comparative Examples 1-5] Except for changing the components and amounts shown in Table 1, the compositions for forming the magnetic parts of the magnetic substrates for Examples 2-32 and Comparative Examples 1-5 are prepared by the same procedure as for Composition 1.

[0183] Next, the magnetic substrates of Examples 2 to 32 and Comparative Examples 1 to 5 are manufactured using the same procedure as the magnetic substrate of Example 1, except that the heat treatment conditions after filling the through-holes of the substrate with the composition are changed to the heat treatment conditions shown in Table 1. The heat treatment is performed using the Step indicated by "○" in Table 1 from Step 1 to Step 11 in Table 1. In this case, the steps are performed in the order of Step 1 to Step 11 in Table 1. For example, in Example 1, the heat treatment is performed in the order of Step 3 ⇒ Step 4 ⇒ Step 7, and in Example 5, the heat treatment is performed in the order of Step 3 ⇒ Step 4 ⇒ Step 9.

[0184] Furthermore, in the volume frequency particle size distribution of the magnetic particles obtained using a laser diffraction scattering particle size distribution analyzer (such as the "LA960N" product manufactured by Horiba, Ltd.) for the mixed powder of magnetic particles constituting the magnetic material portion of each magnetic material-attached substrate in the examples and comparative examples, at least two peak tops were observed, with the particle size at one peak top being 35 to 45 μm and the particle size at the other peak top being 1 to 5 μm.

[0185] Table 1 is shown below.

[0186]

[0187]

[0188]

[0189]

[0190]

[0191]

[0192] From the results in Table 1, it is clear that when the magnetic material portion of the substrate in the example is drilled, grain detachment and cracking are suppressed. Furthermore, from a comparison of the examples, it can be seen that when the Vickers hardness of the magnetic material portion in the substrate with a magnetic material portion is 70 to 160 HV, grain detachment and cracking are less likely to occur when the magnetic material portion is drilled.

[0193] [Substrate with Conductor] Using a 600 μm diameter micro-drill, through-holes (600 μm in diameter) are formed in the magnetic material (1000 μm in diameter) that are filled into the through-holes of the substrate in the substrate 1 with the magnetic material, penetrating in the thickness direction of the substrate. The shape of the opening of the formed through-hole is circular. Next, a copper conductive part with a thickness of 20 μm is formed on the side wall of the formed through-hole by a plating method to form a substrate with a conductor. In the obtained substrate with a conductor, the shortest in-plane distance of the substrate (corresponding to L2 in Figure 3) from the outer edge of the through-hole of the substrate (corresponding to 13E in Figure 3) to the outer edge of the through-hole of the magnetic material (corresponding to 23E in Figure 3) is 200 μm. In other words, the ratio of the shortest in-plane distance to the thickness of the copper conductive part (thickness 20 μm) is 10.

[0194] 10 Substrate with magnetic material part 11 Substrate 13 Through hole in the substrate 15, 21 Magnetic material part Dt Thickness direction 20 Substrate with conductor part 23 Through hole in the magnetic material part 25 Conductor part L1 Thickness of the conductor part 25 13E Outer edge of through hole 13 23E Outer edge of through hole 23 of magnetic material part 21 L2 Shortest in-plane distance of the substrate from the outer edge 13E of through hole 13 to the outer edge 23E of the through hole 23 of magnetic material part 21

Claims

1. A substrate with a magnetic material portion comprising a substrate having through holes and a magnetic material portion containing magnetic particles filled in the through holes, wherein the Vickers hardness of the magnetic material portion is 56 to 160 HV.

2. The substrate with a magnetic material portion according to claim 1, wherein the content of the magnetic material particles is 85% by mass or more of the total mass of the magnetic material portion.

3. The substrate with a magnetic material portion according to claim 1 or 2, wherein the magnetic material particles include ferrite particles, and the content of the ferrite particles is 70% by mass or more of the total mass of the magnetic material particles.

4. The substrate with a magnetic material portion according to claim 1 or 2, wherein the magnetic particles are spherical magnetic particles.

5. The substrate with a magnetic material portion according to claim 1 or 2, wherein in the volume frequency particle size distribution of the magnetic material particles, there are at least two peak tops, and the particle diameter at one peak top is 35 to 45 μm, and the particle diameter at the other peak top is 1 to 5 μm.

6. The substrate with a magnetic material portion according to claim 1 or 2, wherein the magnetic material portion includes a cured epoxy compound.

7. A substrate with a conductor portion comprising a substrate with a magnetic portion as described in claim 1 or 2, and a conductor portion, wherein the magnetic portion of the substrate with the magnetic portion has through holes, and the conductor portion is arranged on the side wall of the through holes of the magnetic portion.

8. The substrate with a conductor portion according to claim 7, wherein the ratio of the shortest in-plane distance of the substrate from the outer edge of the through hole of the substrate to the outer edge of the through hole of the magnetic material portion to the thickness of the conductor portion is 5 to 20.

9. An electronic component comprising a substrate with a conductive portion as described in claim 7.

10. A method for manufacturing a substrate with a conductive portion, comprising: step I, forming a magnetic portion containing magnetic particles and having a Vickers hardness of 56 to 160 HV within the through-holes of a substrate having through-holes; step II, forming through-holes in the magnetic portion; and step III, forming conductive portions on the side walls of the through-holes in the magnetic portion.

Images