Composition, magnetic body, substrate with magnetic body, electronic component, and method for producing structure

Abstract

A first problem to be addressed by the present invention is to provide a composition that exhibits excellent embedding properties when filled into a hole, such as a through hole, formed in a substrate. A second problem to be addressed by the present invention is to provide a magnetic body, a substrate with a magnetic body, an electronic component, and a method for producing a structure.　A composition according to the present invention comprises first magnetic body particles, second magnetic body particles that differ in type from the first magnetic body particles, and a polymerizable compound, wherein at least one of the first magnetic body particles and the second magnetic body particles satisfies the relationship set forth in formula (1).　Formula (1): D90 / D10≤2.50, wherein D10 is a particle diameter at which a cumulative value is 10% in a volume frequency particle size distribution. D90 is a particle diameter at which the cumulative value is 90% in the volume frequency particle size distribution.

Description

Methods for manufacturing compositions, magnetic materials, substrates with magnetic materials, electronic components, and structures.

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

[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 (hereinafter also referred to as "compositions").

[0003] For example, Patent Document 1 describes a soft magnetic material comprising soft magnetic metal powder and resin, wherein the soft magnetic metal powder is composed of particle group α and particle group β, and when the peak intensity of particle group α is IA, the volume of particle group α is Vα, the peak intensity of particle group β is IB, the volume of particle group β is Vβ, and the minimum intensity between particle group α and particle group β is IC, the intensity ratio IC / IA is 0.12 or less, the volume ratio Vα / Vβ is 2.0 or more and 5.1 or less, and in the particle size distribution of the soft magnetic metal powder, particle group α is the particle group containing the maximum peak intensity. The disclosed soft magnetic material is characterized in that the peak particle size PA of particle group α is larger than the peak particle size PB of particle group β, and when the peak intensities of particle group α are numbered IA1, IA2, ..., IAx (x is 1 or more) in descending order, the peak intensity IA of particle group α is set to IA1, the peak particle size PA of particle group α is set to PA1, and when the peak intensities of particle group β are numbered IB1, IB2, ..., IBy (y is 1 or more) in descending order, the peak intensity IB of particle group β is set to IB1, and the peak particle size PB of particle group β is set to PB1. Specifically, the above soft magnetic material is formed by preparing a paste-like soft magnetic material containing a soft magnetic metal powder obtained by mixing multiple types of magnetic particles that can constitute particle group α and particle group β in a predetermined mass ratio, a liquid epoxy resin, and an organic solvent, and then molding this paste-like soft magnetic material into a predetermined shape and curing it.

[0004] Japanese Patent Publication No. 2018-113436

[0005] The present inventors investigated the paste-like soft magnetic material (composition) described in Patent Document 1 and found that it has poor filling properties when filling holes such as through holes in a substrate, and as a result, defects are likely to occur in the magnetic body obtained by curing the composition after filling.

[0006] Therefore, the object of the present invention is to provide a composition that exhibits excellent embedding properties when filling holes such as through holes in a substrate. Another object of the present invention is to provide a method for manufacturing a magnetic material, a substrate with a magnetic material, an electronic component, and a structure.

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

[0008] [1] A composition comprising first magnetic particles, second magnetic particles of a different type from the first magnetic particles, and a polymerizable compound, wherein at least one of the first magnetic particles and the second magnetic particles satisfies the relationship of formula (1). Formula (1) D90 / D10 ≤ 2.50 In the formula, D10 is the particle diameter at which the cumulative value in the volume frequency particle size distribution becomes 10%. D90 is the particle diameter at which the cumulative value in the volume frequency particle size distribution becomes 90%. [2] The composition according to [1], wherein at least one of the first magnetic particles and the second magnetic particles satisfies the relationship of formula (1A). Formula (1A) D90 / D10 ≤ 2.30 In the formula, D10 is the particle diameter at which the cumulative value in the volume frequency particle size distribution becomes 10%. D90 is the particle diameter at which the cumulative value in the volume frequency particle size distribution becomes 90%. [3] The composition according to [1] or [2], wherein at least one of the first magnetic particles and the second magnetic particles satisfies the relationship of formula (2). Formula (2) D90 / D50 ≤ 1.60 where D50 is the particle diameter at which the cumulative value in the volume frequency particle size distribution becomes 50%. D90 is the particle diameter at which the cumulative value in the volume frequency particle size distribution becomes 90%. [4] The composition according to any one of [1] to [3], wherein at least one of the first magnetic particles and the second magnetic particles satisfies the relationship of formula (2A). Formula (2A) D90 / D50 ≤ 1.55 where D50 is the particle diameter at which the cumulative value in the volume frequency particle size distribution becomes 50%. D90 is the particle diameter at which the cumulative value in the volume frequency particle size distribution becomes 90%. [5] The composition according to any one of [1] to [4], wherein the volume frequency value of D90 is 15.0% or less. [6] A composition according to any one of [1] to [5], which is in the form of a paste. [7] A composition according to any one of [1] to [6], wherein when D50 is the particle diameter at which the cumulative value in the volume frequency particle size distribution of the first magnetic particle reaches 50%, and D50 is the particle diameter at which the cumulative value in the volume frequency particle size distribution of the second magnetic particle reaches 50%, T1 > T2 is satisfied, and the first magnetic particle satisfies the relationship of formula (1) above.[8] The composition according to any one of [1] to [7], wherein T1 is the particle diameter D50 at which the cumulative value in the volume frequency particle size distribution of the first magnetic particle becomes 50%, and T2 is the particle diameter D50 at which the cumulative value in the volume frequency particle size distribution of the second magnetic particle becomes 50%, wherein T1 is 10 to 50 μm, and T2 is less than 10 μm. [9] The composition according to any one of [1] to [8], wherein the first magnetic particle and the second magnetic particle each contain at least one selected from the group consisting of Fe, Ni, Co, Zn, and Mn.

[10] A magnetic material obtained by curing the composition according to any one of [1] to [9].

[11] A magnetic material substrate comprising a substrate having holes formed therein and the magnetic material according to

[10] disposed in the holes.

[12] An electronic component comprising the magnetic material substrate according to claim

[11] .

[13] A method for manufacturing a structure, comprising the steps of: forming a plurality of through holes in a substrate that penetrate in the thickness direction; filling the through holes with a composition described in any of [1] to [9]; and forming an inductor region in the substrate.

[0009] According to the present invention, it is possible to provide a composition that exhibits excellent embedding properties when filling holes such as through holes in a substrate. Furthermore, according to the present invention, it is possible to provide a method for manufacturing a magnetic material, a substrate with a magnetic material, an electronic component, and a structure.

[0010] The present invention will now be described in detail. The following descriptions of constituent elements may be based on representative embodiments of the present invention, but the present invention is not limited to such embodiments. In this specification, unless contrary to the spirit of the present invention, the notation of groups (atomic groups) without specifying substituted or unsubstituted includes both unsubstituted and substituted groups. For example, "alkyl group" includes not only unsubstituted alkyl groups but also substituted alkyl groups. Furthermore, in this specification, "organic group" means a group containing at least one carbon atom.

[0011] In this specification, "~" is used to mean that the numbers before and after it are included as the lower and upper limits, respectively.

[0012] In this specification, (meth)acrylate refers to acrylate and methacrylate, (meth)acrylic refers to acrylic and methacrylic, and (meth)acryloyl refers to acryloyl and methacryloyl.

[0013] In this specification, "solid content" of a composition refers to the components that form a magnetic material. Therefore, if the composition contains a solvent (organic solvent, water, etc.), it refers to all components excluding the solvent. Furthermore, any liquid components that form a magnetic material are also considered to be part of the solid content.

[0014] In this specification, "boiling point" means the standard boiling point unless otherwise specified. In this specification, 1 Torr can be converted to 1 mmHg.

[0015] 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.

[0016] 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.

[0017] [Composition] The composition of the present invention comprises first magnetic particles, second magnetic particles of a different type from the first magnetic particles, and a polymerizable compound, wherein at least one of the first magnetic particles and the second magnetic particles satisfies the relationship of formula (1). Formula (1) D90 / D10 ≤ 2.50 In the formula, D10 is the particle diameter at which the cumulative value in the volume frequency particle size distribution becomes 10%. D90 is the particle diameter at which the cumulative value in the volume frequency particle size distribution becomes 90%.

[0018] The composition of the present invention having the above configuration exhibits excellent embedding properties when filling holes such as through holes in a substrate. The reason why the composition having the above configuration can solve the problems of the present invention is not necessarily clear, but the inventors speculate as follows. It should be noted that the mechanism by which the effect is obtained is not limited by the following speculation. In other words, even if the effect is obtained by a mechanism other than that described below, it is included in the scope of the present invention.

[0019] The main features of the composition of the present invention include the inclusion of first magnetic particles and second magnetic particles of a different type from the first magnetic particles, and the fact that the particle size distribution of at least one of the first and second magnetic particles is adjusted to satisfy the relationship of formula (1). As will be described later, magnetic particles having a particle size distribution that satisfies the relationship of formula (1) can be adjusted by removing particles with relatively large particle sizes through a classification process. Here, "different types" refers to cases where the materials are different, such as ferrite and alloy, cases where the constituent elements are of different types, such as Ni-based ferrite and Mn-based ferrite, or cases where the constituent elements are of the same type but the element content ratio is different. With the above configuration, it is hypothesized that when filling the composition into holes such as through holes in a substrate, voids (gaps) of magnetic particles are less likely to occur, and as a result, the occurrence of defects in the magnetic material obtained by hardening the composition after filling can be suppressed. Hereinafter, when filling holes such as through holes in a substrate with the composition in place, superior embedding ability is also referred to as "superior effect of the present invention." The various components contained in the composition of the present invention will be described in detail below.

[0020] [Magnetic Particles] The composition contains first magnetic particles and second magnetic particles different in type from the first magnetic particles. Hereinafter, the first magnetic particles and the second magnetic particles will be described in detail respectively.

[0021] <First Magnetic Particles> The composition contains first magnetic particles. The first magnetic particles usually contain metal atoms. In this specification, the metal atoms include semi-metal atoms such as boron, silicon, germanium, arsenic, antimony, and tellurium. The metal atoms may be contained in the first magnetic particles as an alloy containing a metal element, a metal oxide, a metal nitride, or a metal carbide.

[0022] The metal atoms are not particularly limited, but preferably contain at least one metal atom selected from the group consisting of Fe, Ni, Co, Zn, and Mn. The content (when a plurality of species are included, the total content) of at least one metal atom selected from the group consisting of Fe, Ni, Co, Zn, and Mn is preferably 50% by mass or more, more preferably 60% by mass or more, and still more preferably 70% by mass or more with respect to the total mass of the metal atoms in the first magnetic particles. The upper limit value of the above content is not particularly limited, and is, for example, 100% by mass or less, preferably 98% by mass or less, and more preferably 95% by mass or less.

[0023] The first magnetic particles may contain materials other than Fe, Ni, Co, Zn, and Mn, and specific examples thereof 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 first magnetic particles contain metal atoms other than Fe, Ni, Co, Zn, and Mn, the magnetic particles preferably further contain one or more selected from the group consisting of Si, Cr, B, and Mo.

[0024] The shape of the first magnetic particles is not particularly limited, and may be any of plate-like, elliptical, spherical, and amorphous shapes, but spherical is preferable in terms of more excellent effects of the present invention.

[0025] The first 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 metal atoms selected from the group consisting of Ni and Mn. Furthermore, the ferrite particles may contain materials 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.

[0026] Examples of ferrite particles include Ni ferrite, Mn ferrite, and spinel ferrite (preferably Ni-Zn ferrite, Mn-Zn ferrite, Ni-Zn-Co ferrite, or Fe-Mn ferrite).

[0027] As described above, alloy particles can also be preferably used as the first magnetic particles. The alloy particles preferably contain Fe, as this provides superior effects of the present invention. Examples of metal atoms other than Fe in the alloy particles include Ni and Co. When the 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. The alloy particles may also be amorphous.

[0028] Examples of the 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, and the like.

[0029] Among others, the first magnetic particles preferably contain soft magnetic particles in that the loss is lower. Examples of the soft magnetic particles include Fe-based amorphous alloy particles, Fe—Si—Cr alloy particles, Fe nanocrystalline alloy particles, Fe—Ni—Co alloy particles, Co-based amorphous alloy particles, Ni—Mo alloy particles, Ni ferrite particles, Mn ferrite particles, Ni—Zn-based ferrite particles, Mn—Zn-based ferrite particles, and Ni—Zn—Co-based ferrite particles, and the like.

[0030] At least a part of the surface of the first magnetic particles may be provided with a surface layer. By having the surface layer, the first magnetic particles can be imparted with functions according to the material of the surface layer. Examples of the surface layer include an inorganic layer or an organic layer, and the organic layer is preferred.

[0031] 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.

[0032] 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.

[0033] The thickness of the surface layer is not particularly limited, but 3 to 1000 nm is preferred from the standpoint of allowing the surface layer to perform its function more effectively.

[0034] The volume-average particle diameter of the first magnetic material particles is not particularly limited and is often between 1 and 60 μm. The lower limit of the volume-average particle diameter of the first magnetic material particles is preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 30 μm or more. The upper limit of the volume-average particle diameter of the first magnetic material particles is preferably 50 μm or less. The volume-average particle diameter of the first magnetic material particles is the so-called median diameter (the particle diameter where the cumulative value in the volume-frequency particle size distribution is 50% (D50)), and can be determined based on a particle size distribution curve representing the volume-based frequency distribution of the first magnetic material particles obtained using a laser diffraction scattering particle size distribution analyzer (for example, the "LA960N" product manufactured by Horiba, Ltd.).

[0035] <Second Magnetic Particles> The composition contains second magnetic particles. The second 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 in the second magnetic particles as alloys, metal oxides, metal nitrides, or metal carbides containing metal elements.

[0036] 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 second magnetic particle. 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.

[0037] The second magnetic particles may contain materials other than Fe, Ni, Co, Zn, and Mn, 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, Sr, Zr, Cr, Nb, Pb, Ca, B, C, N, and O. When the second 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 selected from the group consisting of Si, Cr, B, and Mo.

[0038] The shape of the second magnetic particle is not particularly limited and may be plate-shaped, elliptical, spherical, or amorphous; however, a spherical shape is preferred in that it provides superior effects of the present invention.

[0039] As the second magnetic particle, alloy particles or ferrite particles are preferred, and alloy particles are more preferred.

[0040] The alloy particles preferably contain Fe, as this enhances the effects of the present invention. Other metal atoms in the alloy particles include Ni and Co. When the 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 may be 100% by mass or less, preferably 98% by mass or less, and more preferably 95% by mass or less. The alloy particles may also be amorphous.

[0041] 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.

[0042] The second magnetic particle is preferably a ferrite particle, as described above. The ferrite particle preferably contains 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 contains one or more metal atoms selected from the group consisting of Ni and Mn. Furthermore, the ferrite particle may contain materials 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.

[0043] Examples of ferrite particles include Ni ferrite, Mn ferrite, and spinel ferrite (preferably Ni-Zn ferrite, Mn-Zn ferrite, Ni-Zn-Co ferrite, or Fe-Mn ferrite).

[0044] The second magnetic material particles are preferably soft magnetic material particles, in particular, because they have lower losses. Examples of soft magnetic material particles include Fe-based amorphous alloy particles, Fe-Si-Cr alloy particles, Fe nanocrystalline alloy particles, Fe-Ni-Co alloy particles, Co-based amorphous alloy particles, Ni-Mo alloy particles, Ni ferrite particles, Mn ferrite particles, Ni-Zn ferrite particles, Mn-Zn ferrite particles, and Ni-Zn-Co ferrite particles.

[0045] A surface layer may be provided on at least a portion of the surface of the second magnetic particle. Having a surface layer on the second magnetic particle allows for the provision of functions to the second magnetic particle depending on the material of the surface layer. Examples of the surface layer include an inorganic layer or an organic layer, with an organic layer being preferred.

[0046] 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.

[0047] 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.

[0048] The thickness of the surface layer is not particularly limited, but 3 to 1000 nm is preferred from the standpoint of allowing the surface layer to perform its function more effectively.

[0049] The volume-average particle diameter of the second magnetic material particles is not particularly limited, and is often between 1 and 60 μm. The upper limit of the volume-average particle diameter of the second magnetic material particles is preferably less than 10 μm, more preferably 8 μm or less, and even more preferably 5 μm or less. The volume-average particle diameter of the second magnetic material particles is the so-called median diameter (the particle diameter where the cumulative value in the volume frequency particle size distribution is 50% (D50)), and can be determined based on a particle size distribution curve representing the volume-based frequency distribution of the second magnetic material particles obtained using a laser diffraction scattering particle size distribution analyzer (for example, the "LA960N" product manufactured by Horiba, Ltd.).

[0050] <Combination of First and Second Magnetic Particles> The combination of the first and second magnetic particles is preferably a combination of ferrite particles and alloy particles, a combination of ferrite particles and ferrite particles, or a combination of alloy particles and alloy particles, and more preferably a combination of ferrite particles and alloy particles, or a combination of ferrite particles and ferrite particles. Furthermore, when the combination of the first and second magnetic particles is a combination of ferrite particles and alloy 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. Furthermore, when the combination of the first and second magnetic particles is a combination of alloy particles (first alloy particles) and alloy particles (second alloy particles), the content ratio (mass ratio: first alloy particles / second alloy particles) is preferably 30 / 70 to 70 / 30, and more preferably 40 / 60 to 60 / 40. Furthermore, when the combination of the first magnetic particles and the second magnetic particles is a combination of ferrite particles (first ferrite particles) and ferrite particles (second ferrite 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.

[0051] At least one of the first magnetic particle and the second magnetic particle satisfies the relationship of formula (1), and in particular, it is preferable that it satisfies the relationship of formula (1A) in which the effects of the present invention are more superior.

[0052] Equation (1) D90 / D10 ≤ 2.50 where D10 is the particle size at which the cumulative value in the volume frequency particle size distribution becomes 10%. D90 is the particle size at which the cumulative value in the volume frequency particle size distribution becomes 90%.

[0053] Equation (1A) D90 / D10 ≤ 2.30 where D10 is the particle size at which the cumulative value in the volume frequency particle size distribution becomes 10%, and D90 is the particle size at which the cumulative value in the volume frequency particle size distribution becomes 90%.

[0054] Furthermore, among the first and second magnetic particles, the magnetic particle that satisfies the relationship of formula (1) is preferably also satisfied with the relationship of formula (2), and in particular, it is preferable that it satisfies the relationship of formula (2A) in terms of the superior effects of the present invention.

[0055] Equation (2) D90 / D50 ≤ 1.60 where D50 is the particle size at which the cumulative value in the volume frequency particle size distribution becomes 50%, and D90 is the particle size at which the cumulative value in the volume frequency particle size distribution becomes 90%.

[0056] Equation (2A) D90 / D50 ≤ 1.55 where D50 is the particle size at which the cumulative value in the volume frequency particle size distribution becomes 50%, and D90 is the particle size at which the cumulative value in the volume frequency particle size distribution becomes 90%.

[0057] Furthermore, for magnetic particles among the first and second magnetic particles that satisfy the relationship of formula (1), the volume frequency value in D90 is preferably 15.0% or less, more preferably 10.0% or less, and even more preferably 7.0% or less, in terms of superior effects of the present invention. The lower limit is not particularly limited, but for example, it is 0.0% or more.

[0058] When T1 is the volume-average particle diameter of the first magnetic material particle (D50, which is the particle diameter at which the cumulative value in the volume-frequency-particle-size distribution becomes 50%) and T2 is the volume-average particle diameter of the second magnetic material particle (D50, which is the particle diameter at which the cumulative value in the volume-frequency-particle-size distribution becomes 50%), it is preferable that the relationship T1 > T2 is satisfied. T1 is preferably 10 to 50 μm, more preferably 20 to 50 μm, and even more preferably 30 to 50 μm. T2 is preferably less than 10 μm, more preferably 1 to 8 μm, and even more preferably 1 to 5 μm.

[0059] Furthermore, the first magnetic particles and the second magnetic particles are preferable in terms of the superior effects of the present invention, provided that T1 > T2 is satisfied and the first magnetic particle satisfies the relationship of formula (1) (preferably the relationship of formula (1A)), and more preferably T1 > T2 is satisfied and the first magnetic particle satisfies the relationship of formula (1) (preferably the relationship of formula (1A)) and the relationship of formula (2) (preferably the relationship of formula (2A)).

[0060] <Measurement procedure for D10, D50, and D90 of the first and second magnetic particles in the composition> D10, D50, and D90 of the first and second magnetic particles in the composition are determined by the following procedure. D10 is the particle size at which the cumulative value in the volume frequency particle size distribution becomes 10%, D50 is the particle size at which the cumulative value in the volume frequency particle size distribution becomes 50%, and D90 is the particle size at which the cumulative value in the volume frequency particle size distribution becomes 90%.

[0061] If the first magnetic particles and the second magnetic particles can be measured individually, the D10, D50, and D90 values ​​of the first and second magnetic particles can be determined based on a 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.).

[0062] When first magnetic particles and second magnetic particles are present in a mixture, the D10, D50, and D90 values ​​of the first and second magnetic particles can be measured by the following procedure. When performing the following measurements, the magnetic particles may be extracted from the composition by any method (such as firing and sedimentation) and measured, or the film formed from the composition may be measured. The film may be a coating film or a film after curing.

[0063] First, 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. That is, at least 100 particles are extracted for each of the first and second magnetic particles. Next, based on the component results of the elemental analysis, 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 the first and second magnetic particles using a digitizer, and the circular area phase diameter (where 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 is performed by the direct method using a transmission electron microscope with an acceleration voltage of 300 kV. Transmission electron microscopy 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 whose circular area phase diameters have been calculated as described above, 100 particles are arbitrarily selected, and the volume of each particle is calculated using the following formula (1). Formula (1): Volume = (Circular area phase diameter of magnetic particle) 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 D10, D50, and D90 are determined respectively. Similarly, for the second magnetic particle, the volume frequency particle size distribution is obtained in the same manner as for the first magnetic particle, and D10, D50, and D90 are determined respectively.

[0064] In the composition, the total content of the first magnetic particles and the second magnetic particles is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 75% by mass or more, particularly preferably 80% by mass or more, and most preferably 85% by mass or more, based on the total solid content in the composition. Furthermore, the upper limit is preferably 98% by mass or less, and more preferably 96% by mass or less.

[0065] In the composition, the content of the first magnetic particles is preferably 30% by mass or more, and more preferably 40% by mass or more, based on the total amount of magnetic particles in the composition. Furthermore, the upper limit is preferably 70% by mass or less, and more preferably 60% by mass or less.

[0066] In the composition, the content of the second magnetic particles is preferably 30% by mass or more, and more preferably 40% by mass or more, relative to the total amount of magnetic particles in the composition. Furthermore, the upper limit is preferably 70% by mass or less, and more preferably 60% by mass or less.

[0067] <Method for preparing magnetic particles> First magnetic particles that satisfy the relationship in formula (1) above, and second magnetic particles that satisfy the relationship in formula (1) above, can be obtained, for example, by classifying the magnetic particles that will be used as raw materials for each magnetic particle. Classification methods include classification by sieve mesh size, and classification using a rotary vortex classifier and a centrifugal classifier, but classification by sieve mesh size is preferred. By the above method, it is possible to classify particles ranging from the micron order to 100 μm in size. Classification by sieve mesh size can be carried out, for example, by a method based on the JIS Z 8801-1:2019 standard.

[0068] The classification process is preferably carried out on the raw material particle with the larger volume-average particle diameter among the first magnetic material particles and the second magnetic material particles.

[0069] [Polymerizable Compound] The composition contains a polymerizable compound. The polymerizable compound is a compound having polymerizable groups. Examples of polymerizable groups include cyclic polymerizable groups such as epoxy groups and oxetanyl groups, and groups containing ethylenically unsaturated bonds (hereinafter simply referred to as "ethylenically unsaturated groups"), but epoxy groups or oxetanyl groups are preferred. The polymerizable compound is preferably a compound having at least one selected from the group consisting of epoxy groups and oxetanyl groups, more preferably a compound having two or more of at least one selected from the group consisting of epoxy groups and oxetanyl groups, and even more preferably a compound having two or more epoxy groups (hereinafter also referred to as "polyfunctional epoxy compound"). There is no particular upper limit to the number of groups selected from the group consisting of epoxy groups and oxetanyl groups in the polymerizable compound, but for example, it is 15 or less. Furthermore, the epoxy group may be fused with a cyclic group (alicyclic group, etc.). The cyclic group fused with the epoxy group preferably has 5 to 15 carbon atoms. Furthermore, in the above-mentioned cyclic group, the portion other than the fused epoxy group may be monocyclic or polycyclic. A single cyclic group may have only one epoxy group fused to it, or two or more epoxy groups fused to it. Also, the oxetanyl group may be fused to a cyclic group (such as an alicyclic group). The cyclic group fused to the oxetanyl group preferably has 5 to 15 carbon atoms. Furthermore, in the above-mentioned cyclic group, the portion other than the fused oxetanyl group may be monocyclic or polycyclic. A single cyclic group may have only one oxetanyl group fused to it, or two or more oxetanyl groups fused to it.

[0070] Examples of polyfunctional epoxy compounds include bisphenol A type epoxy resins, bisphenol F type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, alicyclic epoxy resins, and aliphatic polyglycidyl ethers. Examples of polyfunctional epoxy compounds include 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 (all manufactured by Mitsubishi Chemical Corporation); EPPN201, EPPN202, EOCN-102, EOCN-10 Examples include 3S, 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.).

[0071] The content of polymerizable compounds (or the total content if multiple polymerizable compounds are included) is preferably 1 to 35% by mass, more preferably 1 to 30% by mass, even more preferably 1 to 25% by mass, particularly preferably 1 to 20% by mass, and most preferably 1 to 15% by mass, based on the total solid content of the composition.

[0072] [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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] The resin content is preferably 0.1 to 30% by mass, and more preferably 0.2 to 10% by mass, based on the total mass of the composition.

[0077] 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.

[0078] <Resin containing repeating units including graft chains> Examples of dispersion resins include resins containing 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.

[0079] If the composition contains resin A, the content of resin A is preferably 0.1 to 30% by mass, more preferably 0.2 to 20% by mass, and even more preferably 0.2 to 10% by mass, based on the total mass of the composition, from the viewpoint of achieving superior effects of the present invention.

[0080] (Repeating units including graft chains) 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] (Hydrophobic Repeating Units) Resin A may also 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.).

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] (Functional groups that can form interactions with magnetic particles) Resin A may have functional groups that can form interactions with magnetic particles. Preferably, 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. If 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.

[0091] 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).

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] (Ethylene-unsaturated group) Resin A may contain an ethylenically unsaturated group. The ethylenically unsaturated group is not particularly limited, but examples include (meth)acryloyl group, vinyl group, and styryl group, with (meth)acryloyl group being preferred. Among the resins A, it is preferable to contain repeating units that have an ethylenically unsaturated group in their side chains, and more preferably to contain repeating units that have an ethylenically unsaturated group in their side chains and are derived from (meth)acrylate (hereinafter also referred to as "(meth)acrylic repeating units containing an ethylenically unsaturated group in their side chains"). A (meth)acrylic 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 the carboxylic acid group in 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 an ethylenically unsaturated group in its side chain can be obtained.

[0097] 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.

[0098] (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.

[0099] (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.

[0100] 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.

[0101] 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.

[0102] <Alkali-Soluble Resin> The 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 already described.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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)acryloyl group is preferred as the ethylenically unsaturated group contained in the side chain. Repeating units containing ethylenically unsaturated groups in their 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 of a (meth)acrylic repeating unit containing a carboxylic acid group.

[0107] 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.).

[0108] 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.

[0109] 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.

[0110] If the composition contains an alkali-soluble resin, the content of the alkali-soluble resin is preferably 0.1 to 40% by mass, more preferably 0.1 to 30% by mass, even more preferably 0.1 to 20% by mass, and particularly preferably 0.1 to 10% by mass, based on the total mass of the composition.

[0111] [Thixotropic Agent] The composition may contain a thixotropic agent (rheology control agent). The thixotropic 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 thixotropic agent is preferably 0.01 to 10% by mass, more preferably 0.01 to 8% by mass, and even more preferably 0.01 to 6% by mass, based on the total solid content of the composition. Examples of thixotropic agents include organic thixotropic agents and inorganic thixotropic agents, with organic thixotropic agents being preferred.

[0112] <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 magnetic particles to adsorb the organic stabilizer onto the surface of the magnetic particles. Examples of the adsorption groups include acidic groups, basic groups, and amide groups. Examples of acidic groups include carboxyl groups, phosphoric acid groups, sulfo 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] (Agglomeration Control Agent) As an organic vibration modifier, an agglomeration control agent can also be mentioned. The agglomeration control agent may be a resin or something other than a resin. The agglomeration control agent has 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 the composition contains an agglomeration control agent, the hard cake formation of magnetic particles in the composition is suppressed, and bulkier aggregates are formed, which can improve redispersibility.

[0118] Examples of flocculation control agents include cellulose derivatives. Examples of cellulose derivatives include carboxymethylcellulose, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, hydroxypropylethylcellulose, and salts thereof.

[0119] (Agglomerating Dispersant) Organic oscillators can also be agglomerating dispersants. The agglomerating dispersant may be a resin or something other than a resin. The agglomerating dispersant adsorbs onto the surface of magnetic particles, separating the magnetic particles from each other, and maintaining a certain distance between the magnetic particles through interactions between the dispersants, thereby preventing the magnetic particles from directly agglomerating together. 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.

[0120] 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.

[0121] 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] The amounts of diamines and tetraamines are adjusted such that the total number of carboxy groups and the total number of amino groups are equivalent according to the number of moles of saturated aliphatic monocarboxylic acids or hydroxy group-containing aliphatic monocarboxylic acids and the number of moles of polybasic acids. For example, when there are 2 moles of aliphatic monocarboxylic acid and n moles (n = 0 to 5) of aliphatic dicarboxylic acid as polybasic acids, if the amount of diamines is (n + 1) moles, the acids and amines are equivalent.

[0126] This amide wax may be obtained as a mixture of a plurality of 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 acid group residue of a saturated aliphatic monocarboxylic acid and / or a hydroxy group-containing saturated aliphatic monocarboxylic acid, B is a dehydrated acid group residue of a polybasic acid, C is a dehydrogenated residue of a diamine and / or a tetraamine, and m is 0 ≤ m ≤ 5.

[0127] One preferred embodiment of the aggregation dispersant is a compound represented by the following formula (II).

[0128]

[0129] In formula (II), R １ represents a monovalent linear aliphatic hydrocarbon group having 10 to 25 carbon atoms, R [[ID=1十七]] ２ and R ３ each independently represent 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 represents a divalent aliphatic hydrocarbon group having 1 to 8 carbon atoms, R ５ and R ６ each independently represent a monovalent aliphatic hydrocarbon group having 1 to 3 carbon atoms or a hydroxyalkyl ether group. In formula (II), L １ to L ３ each independently represent an amide bond. When L １ and L ３ is -CONH-, L ２ is -NHCO-, L１ and L ３ If is -NHCO-, L ２ It is -CONH-.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] 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.

[0136] 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.

[0137] As compounds represented by formula (II), compounds represented by the following formulas (II-1) to (II-9) are preferred.

[0138]

[0139] 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).

[0140] <Inorganic Stabilizers> Examples of inorganic stabilizers include bentonite, silica, calcium carbonate, and smectite.

[0141] [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.

[0142] 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.

[0143] Examples of amine-based curing agents include aliphatic amine-based curing agents, aromatic amine-based curing agents, and amine adduct-based curing agents.

[0144] 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.

[0145] [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.

[0146] 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.

[0147] 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).

[0148] 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, in order to achieve superior effects of the present invention.

[0149] [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.

[0150] [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, from the viewpoint of superior settling stability of magnetic particles, when the rotational speed (shear rate) of the rheometer is 0.1 (1 / s). Here, the viscosity of the composition at 23°C can be measured using MCR-102 (manufactured by Anton Paar).

[0151] [Method for Manufacturing the Composition] The method for manufacturing the composition preferably includes the steps of: subjecting the magnetic particle with the larger volume-average particle diameter among the magnetic particles that will be used as raw materials for the first magnetic particles and the second magnetic particles to a classification treatment to adjust the particle size distribution to satisfy the relationship of formula (1); and mixing one of the first magnetic particles and the second magnetic particles obtained after the classification treatment with other 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 pulverizer, or wet disperser). When manufacturing the composition, each component may be blended all at once, or each component may be dissolved or dispersed in a solvent and then blended sequentially. Furthermore, there are no particular restrictions on the order of addition and working conditions when blending. For example, when using multiple types of other resins, they may be blended all at once, or they may be blended in multiple stages according to type.

[0152] [Applications] The composition can be suitably used as a hole-filling composition for holes (via holes, through holes, via holes, etc.; the holes may be through holes or non-through holes) provided in a substrate. An example of a specific procedure for hole filling is a method including the following steps 1 to 3. Step 1: A step of filling the holes by applying the composition to the surface of a substrate provided with holes such as via holes, through holes, or via holes using a known coating method such as a slit coating method, inkjet coating method, rotary coating method, casting coating method, roll coating method, and screen printing method. Step 2: A step of curing the thermosetting components in the composition by heating the composition on the substrate after step 1 at, for example, about 120 to 240°C for 30 to 240 minutes. Step 3: A step of removing any unwanted portions of the magnetic material protruding from the substrate surface obtained in step 2 by physical polishing to create a flat surface. A substrate containing the above magnetic material can be suitably used as an electronic component such as an inductor equipped in electronic communication equipment, for example.

[0153] 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 magnetic composition by a screen printing method in a reduced pressure environment (preferably a vacuum) to fill the holes with the magnetic composition is preferred.

[0154] The heat treatment in step 2 may be performed multiple times with varying heating temperatures and heating times. The heating temperature in step 2 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 dryer), and a high-frequency heater.

[0155] Another application of the composition is as a film-like magnetic material (hereinafter also referred to as a "magnetic particle-containing film"). An example of a method for manufacturing a magnetic particle-containing film is a method that includes a composition layer formation step and a curing step.

[0156] In the composition layer formation process, the composition is applied to the surface of the substrate to form a layer of the composition (composition layer). For example, a wiring board can be used as the substrate.

[0157] Various coating methods can be applied to the surface of the substrate, including slit coating, inkjet coating, rotary coating, casting coating, roll coating, and screen printing. The thickness of the composition layer is preferably 1 to 10,000 μm, more preferably 10 to 1,000 μm, and even more preferably 15 to 800 μm. The composition layer applied to the surface of the substrate may be heated (pre-baked). Pre-baking is performed, for example, at a temperature of 50 to 140°C for 10 to 1,800 seconds using a hot plate and oven.

[0158] The curing process includes a heat treatment to heat the composition layer. 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 dryer), and a high-frequency heater. The heating temperature in the heat treatment is preferably 120 to 260°C, and more preferably 150 to 240°C. The heating time is not particularly limited, but is preferably 10 to 1800 seconds. The pre-bake in the composition layer formation process may also serve as the heat treatment in the curing process. The substrate containing the magnetic material is suitably used, for example, as an electronic component such as an inductor equipped in electronic communication equipment.

[0159] [Magnetic Material] The magnetic material of the present invention is a product formed by subjecting the above-described composition to heat treatment, and is typically a resin containing magnetic particles formed by subjecting the above-described composition containing a binder component to a heat curing treatment. The shape of the magnetic material is not particularly limited, and for example, as described above, it may be a shape that conforms to the shape of the holes provided in the substrate, or it may be in the form of a film.

[0160] [Electronic Components] The electronic components of the present invention include the magnetic material described above. That is, the electronic components of the present invention may include the magnetic material described above as part of the component. Examples of electronic components include inductors and the like. Known electronic components can be used.

[0161] [Method for Manufacturing a Structure] The present invention also relates to a method for manufacturing a structure. The method for manufacturing a structure according to the present invention comprises the following steps X1 to X3. Step X1: A step of forming a plurality of through holes (e.g., via holes) that penetrate in the thickness direction in a substrate. Step X2: A step of filling the through holes with the composition described above. Step X3: A step of forming an inductor region in the substrate.

[0162] The following describes processes X1 to X3.

[0163] [Process X1] Process X1 is a process of forming a plurality of through holes (e.g., via holes) that penetrate the substrate in the thickness direction. The method of forming the through holes is not particularly limited, but for example, they can be formed using a drill.

[0164] [Step X2] Step X2 is a step of filling the through-holes formed in the substrate in Step X1 with a composition containing magnetic particles. The composition containing magnetic particles is the composition of the present invention as described above. In Step X2, it is preferable to fill the through-holes with the composition by applying it from the upper (front) side of the substrate where the through-holes are provided using a known coating method such as a slit coating method, an inkjet method, a rotary coating method, a casting coating method, a roll coating method, and a screen printing method. At that time, it is preferable to reduce the pressure below the through-holes formed in the substrate from the lower (back) side of the substrate to facilitate the composition being drawn into the through-holes.

[0165] After step X2, the composition filled in the through-holes is subjected to heat treatment to thermocure it. Preferably, the heat treatment conditions are, for example, heating at approximately 120 to 240°C for 30 to 240 minutes. The above heat treatment can be carried out in the same manner as the heat treatment step in step 2 described above, and the preferred embodiments are also the same. After the thermocure of the composition, it is preferable to remove any excess material protruding from the substrate surface of the magnetic material obtained in step X2 by physical polishing to create a flat surface. The above heat treatment can be carried out in the same manner as the planarization step in step 3 described above, and the preferred embodiments are also the same.

[0166] [Step X3] Step X3 is a step of forming an inductor region on the magnetic substrate formed in step X2. Specifically, step X3 preferably involves forming through holes in the magnetic portion of the magnetic substrate that penetrate in the thickness direction of the substrate, and forming a metal layer (preferably a copper layer) inside these through holes.

[0167] 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.

[0168] [Granulation of magnetic particles M-1-0 to M-1-3] ・M-1-0 to M-1-3: Ni-Zn-Co ferrite (hereinafter, the particles before classification will also be called "M-1-0") is classified according to the following procedure to obtain magnetic particles M-1-1 to M-1-3. M-1-1 is the magnetic particle fraction that passed through the 63 μm sieve when classified with a 63 μm sieve. M-1-2 is the magnetic particle fraction that passed through the 53 μm sieve when classified with a 53 μm sieve. M-1-3 is the magnetic particle fraction that passed through the 45 μm sieve when classified with a 45 μm sieve.

[0169] <Classification Procedure> Using Sanpo stainless steel sieves (200 mm diameter, 45 mm depth, JIS Z 8801-1:2019 standard) with mesh sizes of 63 μm, 53 μm, and 45 μm, magnetic particles are classified step by step. Approximately 100 g of magnetic powder is placed on the sieve, and the sieve is shaken manually for several minutes. The powder that passes through the sieve (approximately 60% to 80%) is collected at the bottom. The same process is repeated by changing to a sieve with a smaller mesh size, and the coarse particles are reduced by processing in steps from 63 μm to 53 μm and then to 45 μm.

[0170] <Measurement of Particle Size Distribution of Magnetic Particles> The volume frequency particle size distribution (volume-based particle size distribution) of each magnetic particle (M-1-0 to M-1-3) is measured using a laser diffraction scattering particle size distribution analyzer (LA960N, manufactured by Horiba, Ltd.). D50 (particle diameter (median diameter) at which the cumulative value in the volume frequency particle size distribution becomes 50%), D10 (particle diameter at which the cumulative value in the volume frequency particle size distribution becomes 10%), and D90 (particle diameter at which the cumulative value in the volume frequency particle size distribution becomes 90%) are determined for each magnetic particle. From these values, "D90 / D50" and "D90 / D10" are calculated. The volume-based frequency (%) at D90 for each magnetic particle is also determined from the volume frequency particle size distribution. The table below shows "D50 (μm)", "D90 / D50", "D90 / D10", and "Volume-based frequency (%) at D90" for each magnetic particle.

[0171]

[0172] [Various components contained in the composition] The various components used in the preparation of the composition are listed below.

[0173] [Magnetic Particles] ・M-1-0: Magnetic particle shown in Table 1 (Ni-Zn-Co ferrite) ・M-1-1: Magnetic particle shown in Table 1 (M-1-0 after classification) ・M-1-2: Magnetic particle shown in Table 1 (M-1-0 after classification) ・M-1-3: Magnetic particle shown in Table 1 (M-1-0 after classification) ・M-2: Product name "ATFINE NC1" (Fe-based nanocrystalline magnetic material, manufactured by Epson Atomics Co., Ltd., D50: 3.1 μm) ・M-3: Mn-based ferrite (D50: 3.7 μm) ・M-4: Mn-based ferrite (D50: 0.1 μm) Note that for each of the magnetic particles M-2 to M-4, D90 / D10 > 2.50.

[0174] [Resin] ・B-1: Product name "Hinoact T-6000" (manufactured by Kawaken Fine Chemical Co., Ltd.) ・B-2: Compound with the following structure (The numerical values ​​(a to d) in each repeating unit represent the content (mass%) relative to the total number of repeating units. In the following structural formula, from left to right, these were 35% by mass, 35.8% by mass, 16% by mass, and 13.2% by mass.)

[0175]

[0176] • B-3: Compound with the following structure (The numerical values ​​(a to e) in each repeating unit represent the content (mass%) relative to the total number of repeating units. In the following structural formula, the content was 12.1% by mass, 45% by mass, 5.7% by mass, 4.9% by mass, and 32.3% by mass from left to right.)

[0177]

[0178] • B-4: Compound with the following structure (The numerical values ​​(a to e) in each repeating unit represent the content (mass%) relative to the total number of repeating units. In the following structural formula, a to e were 89.6% by mass, 8.8% by mass, 1.1% by mass, and 0.3% by mass and 0.2% by mass, respectively.)

[0179]

[0180] • B-5: Compound with the following structure (The numerical values ​​(a to f) in each repeating unit represent the content (mass%) relative to the total number of repeating units. In the following structural formula, a to f were 88.4% by mass, 9.8% by mass, 0.25% by mass, 0.25% by mass, 0.1% by mass, and 1.2% by mass, respectively.)

[0181]

[0182] [Additives] <Rheology control agents> ・C-1: Product name "Flonon RCM-100" (fatty acid ester / aromatic ester, manufactured by Kyoeisha Chemical Co., Ltd.) ・C-2: Product name "Talen VA705B" (higher fatty acid amide, manufactured by Kyoeisha Chemical Co., Ltd.)

[0183] <Hardening Agents> ・D-1: Ricacid MTA-15 (manufactured by Shin Nippon Rika Co., Ltd.) ・D-2: 4,4-diaminodiphenylsulfone (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0184] <Epoxy Compounds> ・E-1: Denacol EX-314 (Glycerol polyglycidyl ether, manufactured by Nagase ChemteX Corporation) ・E-2: Ethyl-3-methyl-3-phenylglycidate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) ・E-3: Product name "jER871" (Mitsubishi Chemical Corporation) ・E-4: Product name "jER890" (Mitsubishi Chemical Corporation) ・E-5: 4,4'-methylenebis(N,N-diglycidylaniline) (manufactured by Tokyo Chemical Industries, Ltd.) ・E-6: N,N-diglycidyl-4-glycidyloxyaniline (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) ・E-7: 1,2-cyclohexanedicarboxylic acid diglycidyl (manufactured by Tokyo Chemical Industries, Ltd.) ・E-8: Denacol EX-614 (Glycerol polyglycidyl ether, manufactured by Nagase ChemteX Corporation)

[0185] <Solvents> ・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.)

[0186] [Preparation of Compositions for Examples and Comparative Examples] The components other than the solvent listed in Table 2 were mixed to achieve the composition (mass%) shown in Table 2, and placed in a sealed container made of PTFE (polytetrafluoroethylene). Subsequently, the solvent was added to achieve the composition (mass%) shown in Table 2, the container was sealed, and the mixture was dispersed at 50 G for 1 hour using a RAM (Low-Frequency Resonance Acoustic Mixer) manufactured by Resodyn Corporation to prepare the compositions for each example and comparative example.

[0187] [Evaluation] [Evaluation of Embedding Properties] The embedding properties of the compositions of the examples and comparative examples are evaluated by the following method. Multiple through holes (vias) with a diameter of 450 μm are formed in a 1 mm thick PCB substrate using a micro-drill. The spacing between the through holes is 450 μm, and 5 holes × 10 rows (500 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 the composition containing magnetic particles 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 by heat treatment at 150°C for 20 minutes and then at 200°C for 60 minutes. After that, the magnetic material that has protruded from the top and bottom surfaces of the substrate is polished and removed to flatten the substrate, thereby forming a magnetic material portion within the substrate. An X-ray CT scanner (Xradia 610 Versa (Carl Zeiss)) is used to observe the presence or absence of defects in the through-holes of the substrate embedded with magnetic material using a W-ray source, and the number of through-holes in which defects occurred is measured. The measured values ​​are classified and evaluated according to the following evaluation criteria. "B" or higher is preferable, and "A" is most preferable. "A": Less than 5 holes "B": 5 holes or more but less than 10 holes "C": 10 holes or more

[0188] The evaluation is shown in Table 2 below.

[0189]

[0190]

[0191]

[0192] Table 2 clearly shows that the composition of the present invention exhibits excellent embedding properties when filling holes such as through holes in a substrate. Furthermore, the results in the table confirm that when at least one of the first magnetic particles and the second magnetic particles satisfies the relationship of formula (1A), the embedding properties when filling holes such as through holes in a substrate are even better.

Claims

1. A composition comprising first magnetic particles, second magnetic particles of a different type from the first magnetic particles, and a polymerizable compound, wherein at least one of the first magnetic particles and the second magnetic particles satisfies the relationship of formula (1). Formula (1) D90 / D10 ≤ 2.50 In the formula, D10 is the particle size at which the cumulative value in the volume frequency particle size distribution becomes 10%. D90 is the particle size at which the cumulative value in the volume frequency particle size distribution becomes 90%.

2. The composition according to claim 1, wherein at least one of the first magnetic particles and the second magnetic particles satisfies the relationship of formula (1A). Formula (1A): D90 / D10 ≤ 2.30, where D10 is the particle size at which the cumulative value in the volume frequency particle size distribution becomes 10%, and D90 is the particle size at which the cumulative value in the volume frequency particle size distribution becomes 90%.

3. The composition according to claim 1 or 2, wherein at least one of the first magnetic particles and the second magnetic particles satisfies the relationship of formula (2): Formula (2) D90 / D50 ≤ 1.60 where D50 is the particle size at which the cumulative value in the volume frequency particle size distribution becomes 50%, and D90 is the particle size at which the cumulative value in the volume frequency particle size distribution becomes 90%.

4. The composition according to claim 3, wherein at least one of the first magnetic particles and the second magnetic particles satisfies the relationship of formula (2A). Formula (2A): D90 / D50 ≤ 1.55, where D50 is the particle size at which the cumulative value in the volume frequency particle size distribution becomes 50%, and D90 is the particle size at which the cumulative value in the volume frequency particle size distribution becomes 90%.

5. The composition according to claim 1 or 2, wherein the volume frequency value in D90 is 15.0% or less.

6. The composition according to claim 1 or 2, which is in the form of a paste.

7. The composition according to claim 1 or 2, wherein when D50 is the particle diameter at which the cumulative value in the volume frequency particle size distribution of the first magnetic particle becomes 50% (T1) and D50 is the particle diameter at which the cumulative value in the volume frequency particle size distribution of the second magnetic particle becomes 50% (T2), T1 > T2 and the first magnetic particle satisfies the relationship of formula (1).

8. The composition according to claim 1 or 2, wherein when D50 is the particle diameter at which the cumulative value in the volume frequency particle size distribution of the first magnetic particle becomes 50%, and D50 is the particle diameter at which the cumulative value in the volume frequency particle size distribution of the second magnetic particle becomes 50%, T1 is 10 to 50 μm, and T2 is less than 10 μm.

9. The composition according to claim 1 or 2, wherein the first magnetic particle and the second magnetic particle each include at least one selected from the group consisting of Fe, Ni, Co, Zn, and Mn.

10. A magnetic material obtained by curing the composition according to claim 1 or 2.

11. A substrate with a magnetic material, comprising a substrate having a hole formed therein, and a magnetic material according to claim 10 disposed within the hole.

12. An electronic component comprising a magnetic substrate as described in claim 11.

13. A method for manufacturing a structure, comprising the steps of: forming a plurality of through holes in a substrate that penetrate in the thickness direction; filling the through holes with the composition described in claim 1 or 2; and forming an inductor region in the substrate.

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