Electromagnetic wave shielding material, electronic component, and electronic device

Abstract

Provided is an electromagnetic wave shielding material having a magnetic layer containing magnetic particles and a resin, wherein: the electromagnetic wave shielding material has at least one adjacent layer that is in direct contact with the magnetic layer; and the 90% cumulative frequency diameter D90 obtained by measuring the particle size distribution of the magnetic particles contained in the magnetic layer is 1500 μm or less.

Description

Electromagnetic wave shielding material, electronic component, and electronic device

[0001] The present invention relates to an electromagnetic wave shielding material, an electronic component, and an electronic device.

[0002] In recent years, electromagnetic wave shielding materials have attracted attention as materials for reducing the influence of electromagnetic waves in various electronic components and various electronic devices (see, for example, Patent Document 1). An electromagnetic wave shielding material can exhibit the performance of shielding electromagnetic waves (hereinafter also referred to as "electromagnetic wave shielding performance" or "shielding performance") by reflecting electromagnetic waves incident on the electromagnetic wave shielding material with the electromagnetic wave shielding material and / or attenuating the electromagnetic waves inside the electromagnetic wave shielding material.

[0003] WO2024 / 004889A1

[0004] Patent Document 1 discloses an electromagnetic wave shielding material having a multilayer structure including a magnetic layer. For an electromagnetic wave shielding material having a multilayer structure, excellent interlayer adhesion is desired.

[0005] An aspect of the present invention aims to provide an electromagnetic wave shielding material having a multilayer structure including a magnetic layer, which is excellent in interlayer adhesion.

[0006] As a result of repeated studies by the present inventors, it has surprisingly been found that controlling the D90 of magnetic particles, which will be described in detail below, contributes to improving the adhesion between the magnetic layer and the adjacent layer. As a result of further intensive studies, the present inventors have newly found that a magnetic layer containing magnetic particles with a D90 of 1500 μm or less has excellent adhesion to an adjacent layer.

[0007] In other words, one aspect of the present invention is as follows: [1] An electromagnetic wave shielding material having a magnetic layer containing magnetic particles and resin, wherein there is at least one adjacent layer in direct contact with the magnetic layer, and the 90% cumulative frequency diameter D90 (hereinafter also simply referred to as "D90") obtained by measuring the particle size distribution of the magnetic particles contained in the magnetic layer is 1500 μm or less. [2] The electromagnetic wave shielding material according to [1], wherein the adjacent layer is on one surface side and the other surface side of the magnetic layer. [3] The electromagnetic wave shielding material according to [2], wherein the adjacent layer is a metal layer. [4] The electromagnetic wave shielding material according to [2], wherein the adjacent layer is a resin-containing layer. [5] The electromagnetic wave shielding material according to [4], wherein the magnetic layer is between two metal layers, and the resin-containing adjacent layer is located between one of the two metal layers and the magnetic layer, and between the other metal layer and the magnetic layer. [6] The electromagnetic wave shielding material according to any one of [1] to [5], wherein the content of the resin in the magnetic layer is 15 parts by mass or more and 25 parts by mass or less per 100 parts by mass of the total mass of the magnetic layer. [7] The resin of the magnetic layer is a urethane resin and the following formula 1: An electromagnetic wave shielding material according to any one of [1] to [6], comprising a resin having a substructure represented by and , wherein in formula 1, * represents the bonding position with adjacent atoms. [8] The adjacent layer is on one surface side and the other surface side of the magnetic layer, the adjacent layer is a metal layer, the content of the resin in the magnetic layer is 15 parts by mass or more and 25 parts by mass or less per 100 parts by mass of the total mass of the magnetic layer, and the resin of the magnetic layer is a urethane resin and the following formula 1: An electromagnetic wave shielding material according to [1], comprising a resin having a substructure represented by and , wherein in formula 1, * represents the bonding position with an adjacent atom. [9] The adjacent layer is located on one surface side and the other surface side of the magnetic layer, the adjacent layer is a resin-containing layer, the magnetic layer is located between two metal layers, the resin-containing adjacent layer is located between one of the two metal layers and the magnetic layer, and between the other metal layer and the magnetic layer, the resin content in the magnetic layer is 15 parts by mass or more and 25 parts by mass or less per 100 parts by mass of the total mass of the magnetic layer, and the resin in the magnetic layer is a urethane resin and the following formula 1: An electromagnetic shielding material according to [1], comprising a resin having a substructure represented by and , wherein in formula 1, * represents the bonding position with an adjacent atom. An electronic component comprising the electromagnetic shielding material according to any one of [1] to [9]. An electronic device comprising the electromagnetic shielding material according to any one of [1] to [9].

[0008] According to one aspect of the present invention, an electromagnetic wave shielding material having a multilayer structure including a magnetic layer can be provided, which exhibits excellent interlayer adhesion. Furthermore, according to one aspect of the present invention, an electronic component and an electronic device containing this electromagnetic wave shielding material can be provided.

[0009] [Electromagnetic wave shielding material] One aspect of the present invention relates to an electromagnetic wave shielding material having a magnetic layer containing magnetic particles and a resin, wherein the material has at least one adjacent layer in direct contact with the magnetic layer, and the 90% cumulative frequency diameter D90 obtained by measuring the particle size distribution of the magnetic particles contained in the magnetic layer is 1500 μm or less.

[0010] In the present invention and this specification, "electromagnetic wave shielding material" means a material that can exhibit shielding performance against electromagnetic waves of at least one frequency or at least a portion of a frequency band. "Electromagnetic waves" include magnetic field waves and electric field waves. An "electromagnetic wave shielding material" can be a material that can exhibit shielding performance against one or both of the following: magnetic field waves of at least one frequency or at least a portion of a frequency band, and electric field waves of at least one frequency or at least a portion of a frequency band.

[0011] In the present invention and this specification, "magnetic" means ferromagnetic property.

[0012] In the present invention and this specification, "in direct contact" means that two layers are adjacent to each other without any other layers in between.

[0013] The electromagnetic shielding material described above will be explained in more detail below.

[0014] <Magnetic Layer> (Magnetic Particles) The magnetic layer is a layer containing magnetic particles and resin. As magnetic particles, one type selected from the group consisting of magnetic particles generally called soft magnetic particles, such as metal particles and ferrite particles, can be used, or two or more types can be used in any ratio. Since metal particles generally have a saturation magnetic flux density about 2 to 3 times that of ferrite particles, they can maintain relative permeability without magnetic saturation even under a strong magnetic field and exhibit shielding performance. Therefore, it is preferable that the magnetic particles contained in the magnetic layer are metal particles.

[0015] Magnetic particles can be of any shape, such as spherical, needle-shaped, or flattened. Flattened particles are preferred from the viewpoint of improving the shielding performance of electromagnetic shielding materials because they have a small demagnetizing field in the in-plane direction, resulting in high magnetic permeability. In the present invention and this specification, "flattened particles" refers to particles with an aspect ratio of 0.20 or less. For flattened particles and aspect ratios, refer to paragraphs 0031 to 0033 of WO2022 / 255022A1.

[0016] In one embodiment, the shielding performance of an electromagnetic shielding material against electromagnetic waves can be evaluated using the permeability (more specifically, the real part of the complex relative permeability) of the magnetic layer contained in the electromagnetic shielding material as an indicator. Electromagnetic shielding materials having a magnetic layer exhibiting high permeability (more specifically, the real part of the complex relative permeability) are preferable because they can exhibit high shielding performance against electromagnetic waves.

[0017] When the complex relative permeability is measured using a permeability measuring device, the real part μ' and the imaginary part μ'' are usually displayed. In this invention and specification, the real part of the complex relative permeability refers to this real part μ'. Hereafter, the real part of the complex relative permeability at a frequency of 3 MHz (megahertz) will also be simply referred to as "permeability" or "permeability μ'". Permeability can be measured using a commercially available permeability measuring device or a permeability measuring device with a known configuration. The measurement temperature is 25°C. By setting the ambient temperature around the sample to the measurement temperature, the temperature of the sample can be set to the measurement temperature by achieving temperature equilibrium. From the viewpoint of exhibiting even better electromagnetic shielding performance, the permeability of the magnetic layer contained in the electromagnetic shielding material (real part of the complex relative permeability at a frequency of 3 MHz) is preferably 40 or more, and more preferably 100 or more. Furthermore, the magnetic permeability can be, for example, 500 or less, 300 or less, or 200 or less, and may exceed the values ​​exemplified herein. Electromagnetic shielding materials with high magnetic permeability are preferable because they exhibit excellent electromagnetic shielding performance.

[0018] Examples of metal particles used as magnetic particles include Sendust (Fe-Si-Al alloy), Permalloy (Fe-Ni alloy), Molybdenum Permalloy (Fe-Ni-Mo alloy), Fe-Si alloy, Fe-Cr alloy, Fe-containing alloys generally called iron-based amorphous alloys, Co-containing alloys generally called cobalt-based amorphous alloys, alloys generally called nanocrystalline alloys, iron, and Permendur (Fe-Co alloy). Among these, Sendust is preferred because it exhibits high saturation magnetic flux density and relative permeability. In addition to the constituent elements of the metal (including alloys), the metal particles may contain elements contained in additives that can be optionally added and / or elements contained in impurities that may be unintentionally introduced during the manufacturing process of the metal particles, in any desired proportion. In metal particles, the content of constituent elements of the metal (including alloys) is preferably 90.0% by mass or more, more preferably 95.0% by mass or more, and may also be 100% by mass, less than 100% by mass, 99.9% by mass or less, or 99.0% by mass or less.

[0019] D90 The 90% cumulative frequency diameter D90 obtained by measuring the particle size distribution of magnetic particles contained in the magnetic layer in the present invention and this specification is the 90% cumulative frequency diameter in the volume-based particle size distribution measured by laser diffraction scattering. The particle size distribution measurement is performed using magnetic particles extracted from the magnetic layer by a known method as the measurement sample. The method for extracting magnetic particles from the magnetic layer and the method for measuring the particle size distribution can be described in the Examples section below.

[0020] The D90 of the magnetic particles contained in the magnetic layer is preferably 1500 μm or less, and more preferably 1400 μm or less, from the viewpoint of improving adhesion between the magnetic layer and adjacent layers, in the order of 1300 μm or less, 1200 μm or less, 1100 μm or less, 1000 μm or less, and less than 1000 μm. The D90 of the magnetic particles contained in the above magnetic layer is, for example, 300 μm or more, and more preferably 400 μm or more from the viewpoint of increasing the permeability of the magnetic layer. For example, using classified magnetic particles as magnetic particles added to the magnetic layer forming composition can contribute to reducing the D90 value of the magnetic particles contained in the magnetic layer. Classification can be performed, for example, by sieving using a sieve. Commercially available sieves such as nylon mesh can be used as sieves. By using a sieve with a small mesh opening, the D90 value of the magnetic particles contained in the magnetic layer can be reduced.

[0021] The content of magnetic particles in the magnetic layer described above can be, for example, 50 parts by mass or more, 60 parts by mass or more, 70 parts by mass or more, or 80 parts by mass or more, per 100 parts by mass of the total mass of the magnetic layer, or for example, 87 parts by mass or less, 85 parts by mass or less, 80 parts by mass or less, or 75 parts by mass or less. The magnetic layer may contain only one type of magnetic particle, or it may contain two or more types of magnetic particles in any proportion. In the present invention and this specification, when two or more types of a component are included, the content refers to the total content of those components. The content of various components in the magnetic layer can be determined by known methods such as TG / DTA (Thermogravimetric Analysis) or extraction of various components using a solvent. Note that "TG / DTA" is generally called thermogravimetric differential thermal analysis. If the composition of the magnetic layer-forming composition used to form the magnetic layer is known, the content of various components in the magnetic layer can also be determined from this known composition.

[0022] (Resin) The magnetic layer contains resin along with magnetic particles. In the present invention and this specification, "resin" means polymer, and includes rubber and elastomer. Polymers include homopolymers and copolymers. Rubber includes natural rubber and synthetic rubber. Elastomer is a polymer that exhibits elastic deformation. In the magnetic layer, the same or different resins may be crosslinked with a curing agent or the like. In the present invention and this specification, a layer containing both magnetic particles and resin corresponds to a "magnetic layer". The resin content in the magnetic layer can be, for example, 10 parts by mass or more per 100 parts by mass of the total mass of the magnetic layer, and from the viewpoint of further improving adhesion with adjacent layers, it is preferably 15 parts by mass or more, and more preferably 18 parts by mass or more. On the other hand, the resin content in the magnetic layer can be, for example, 40 parts by mass or less per 100 parts by mass of the total mass of the magnetic layer. From the viewpoint of increasing the permeability of the magnetic layer, it is preferably 35 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 25 parts by mass or less.

[0023] Resins can act as binders in the magnetic layer. Examples of resins included in the magnetic layer include conventionally known thermoplastic resins, thermosetting resins, UV-curable resins, radiation-curable resins, rubber-based materials, and elastomers. Specific examples include polyester resins, polyethylene resins, polyvinyl chloride resins, polyvinyl butyral resins, polyurethane resins, polyester urethane resins, cellulose resins, acrylic resins, ABS (acrylonitrile-butadiene-styrene) resins, nitrile-butadiene rubbers, styrene-butadiene rubbers, epoxy resins, phenolic resins, amide resins, silicone resins, styrene elastomers, olefin elastomers, vinyl chloride elastomers, polyester elastomers, polyamide elastomers, polyurethane elastomers, and acrylic elastomers. In the present invention and this specification, the term "urethane resin" is used as a general term for resins having urethane bonds.

[0024] In addition to the above components, the magnetic layer may also contain in any amount one or more of the following known additives: a curing agent, a curing accelerator, a polymerization initiator, a catalyst, a dispersant, a stabilizer, a surface treatment agent for magnetic particles (such as a silane coupling agent or other coupling agent), and a crosslinking agent.

[0025] The curing agent can play a role in improving the strength and durability of the magnetic layer. Examples of curing agents included in the magnetic layer include thermosetting resins, photocurable resins (e.g., UV-curable resins, radiation-curable resins, etc.), and moisture-curable resins. Specific examples include isocyanates, polyols, epoxy resins, acid anhydrides, polyamines, phenolic resins, unsaturated polyester resins, urea resins, and diallyl phthalates. Part or all of the curing agent may be present in the magnetic layer in a form after the curing reaction. As an example, one form of resin in the magnetic layer is a form in which multiple types of resins are crosslinked by the curing agent.

[0026] Examples of isocyanates include aliphatic polyisocyanates, aromatic polyisocyanates, aromatic aliphatic polyisocyanates, and alicyclic polyisocyanates. Specific examples of aliphatic polyisocyanates include HDI (Hexamethylene disocyanate), the TMP (Trimethyrolpropane) adduct of HDI, the biuret adduct of HDI, and the isocyanurate adduct of HDI. Specific examples of aromatic polyisocyanates include TDI (Tolylene disocyanate), the adduct of TDI with a polyol compound (e.g., the TMP adduct of TDI), the biuret adduct of TDI, and the isocyanurate adduct of TDI. Specific examples of aromatic aliphatic polyisocyanates include XDI (Xylylene Disocyanate), the TMP adduct of XDI, the biuret of XDI, and the isocyanurate of XDI. Specific examples of alicyclic polyisocyanates include IPDI (Isophorone Disocyanate), the TMP adduct of IPDI, the biuret of IPDI, and the isocyanurate of IPDI.

[0027] Examples of epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol epoxy resin, naphthol novolac epoxy resin, phenol novolac type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, glycidylamine type epoxy resin, glycidyl ester type epoxy resin, cresol novolac type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin, epoxy resin having a butadiene structure, alicyclic epoxy resin, heterocyclic epoxy resin, spiroring-containing epoxy resin, cyclohexanedimethanol type epoxy resin, naphthylene ether type epoxy resin, and trimethylol type epoxy resin. Epoxy resins may be used individually or in combination of two or more types in any proportion. A composition containing epoxy resin can be cured by the ring-opening of the epoxy groups contained in the epoxy resin upon heating, forming a cross-linked structure. In a magnetic layer formed by curing a composition containing epoxy resin, some or all of the epoxy groups contained in the epoxy resin may be present in a state where they have opened their rings and formed a cross-linked structure.

[0028] Examples of reaction catalysts include imidazoles, sulfonic acids, DBU (1,8-diazabicyclo[5.4.0]-7-undecene) salts, amines, heavy metals, acids, and cyclic ethers.

[0029] For example, a magnetic layer formed using a magnetic layer-forming composition containing a urethane resin, an epoxy resin, and an isocyanate may include a urethane resin and a resin having a substructure represented by the following formula 1. In formula 1, * represents the bonding position with adjacent atoms.

[0030]

[0031] The substructure represented by formula 1 is an amino group derived from the isocyanate group of the isocyanate (for example, an isocyanate group and H ２It can be formed by the reaction of an amino group (generated by reaction with O) and an epoxy group of the epoxy resin. In the magnetic layer, the resin having the substructure represented by formula 1 and the urethane resin may or may not be crosslinked by a curing agent, etc. This also applies to the resin having one or more substructures selected from the group consisting of the substructure represented by formula 1-1, the substructure represented by formula 1-2, and the substructure represented by formula 1-3 below and the urethane resin.

[0032] In one embodiment, a magnetic layer formed using a magnetic layer-forming composition comprising a urethane resin, an epoxy resin, and an isocyanate may include a urethane resin and a resin having one or more substructures selected from the group consisting of a substructure represented by formula 1-1, a substructure represented by formula 1-2, and a substructure represented by formula 1-3. In formulas 1-1, 1-2, and 1-3, * represents the bonding position with an adjacent atom. Each of the substructures represented by formulas 1-1, 1-2, and 1-3 includes the substructure represented by formula 1. In another embodiment, the resin included in the magnetic layer may be a resin having a substructure represented by formula 1, but not having the substructures represented by formulas 1-1, 1-2, and 1-3.

[0033]

[0034] For example, a magnetic layer formed using a magnetic layer-forming composition containing a urethane resin, an epoxy resin, and HDI may include a urethane resin and a resin having a substructure represented by formula 1-1. A magnetic layer formed using a magnetic layer-forming composition containing a urethane resin, an epoxy resin, and HDI may include a urethane resin and a resin having a substructure represented by formula 1-2 and / or a substructure represented by formula 1-3.

[0035] It is preferable for the magnetic layer to include a urethane resin and a resin having a substructure represented by Formula 1, from the viewpoint of further improving the adhesion between the magnetic layer and adjacent layers, and from the viewpoint of improving the strength of the magnetic layer. From these viewpoints, it is more preferable for the magnetic layer to include a urethane resin and a resin having one or more substructures selected from the group consisting of Formulas 1-1, 1-2, and 1-3.

[0036] The presence of urethane resin and resin having the above-mentioned substructure in the magnetic layer can be confirmed by known methods.

[0037] For example, a silane coupling agent can be used as a surface treatment agent for magnetic particles. Surface treatment of magnetic particles can be carried out by known methods such as wet methods and dry methods. A silane coupling agent is an organosilicon compound having an organic group and a hydrolyzable group. Examples of hydrolyzable groups include alkoxy groups, acyloxy groups, and halogeno groups.

[0038] Silane coupling agents may have hydrophobic groups. Examples of silane coupling agents having hydrophobic groups as functional groups include alkoxysilanes such as methyltrimethoxysilane (MTMS), dimethyldimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, and decyltrimethoxysilane; chlorosilanes such as methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, and phenyltrichlorosilane; and hexamethyldisilazane (HMDS).

[0039] The silane coupling agent may have a vinyl group. Examples of the silane coupling agent having a vinyl group include alkoxysilanes such as methacryloxypropyltriethoxysilane, methacryloxypropyltrimethoxysilane, methacryloxypropylmethyldiethoxysilane, methacryloxypropylmethyldimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, and vinylmethyldimethoxysilane; chlorosilanes such as vinyltrichlorosilane and vinylmethyldichlorosilane; and divinyltetramethyldisilazane, etc.

[0040] The silane coupling agent may have an amino group. Examples of the silane coupling agent having an amino group include aminopropyltriethoxysilane, aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-8-aminooctyltrimethoxysilane, aminoalkoxysilanes of both-terminal amine type (e.g., FM-3311, FM-3321, FM-3325 manufactured by JNC Corporation), and polyfunctional amine type aminoalkoxysilanes (e.g., X-12-972F manufactured by Shin-Etsu Chemical Co., Ltd.), etc.

[0041] The silane coupling agent may have an epoxy group. Examples of the silane coupling agent having an epoxy group include 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, and 8-glycidoxyoctyltrimethoxysilane, etc.

[0042] The silane coupling agent may have an isocyanate group. Examples of the silane coupling agent having an isocyanate group include 3-isocyanatopropyltriethoxysilane and 3-isocyanatopropyltrimethoxysilane, etc.

[0043] The above electromagnetic wave shielding material may include only one magnetic layer in which the D90 of the magnetic particles is 1500 μm or less, or may include two or more such magnetic layers.

[0044] When the electromagnetic shielding material contains only one magnetic layer, the thickness of this single magnetic layer can be, for example, 5 μm or more, and from the viewpoint of further improving the shielding performance of the electromagnetic shielding material, it is preferable to have a thickness of 10 μm or more, and more preferably 20 μm or more. On the other hand, the thickness of this single magnetic layer can be, for example, 100 μm or less or 90 μm or less, and from the viewpoint of improving the moldability of the electromagnetic shielding material, it is preferable to have a thickness of less than 90 μm, more preferably 80 μm or less, and even more preferably 70 μm or less. When the electromagnetic shielding material contains two or more magnetic layers, the thickness of each of these two or more magnetic layers (i.e., the thickness per layer) can be, for example, 5 μm or more, and from the viewpoint of further improving the shielding performance of the electromagnetic shielding material, it is preferable to have a thickness of 10 μm or more, and more preferably 20 μm or more. On the other hand, the thickness of this single magnetic layer can be, for example, 100 μm or less or 90 μm or less, and it is preferable to have a thickness of less than 90 μm, and more preferably 80 μm or less. The thicknesses of two or more magnetic layers can be the same or different. The thickness of each layer in the electromagnetic shielding material can be determined by imaging a cross-section exposed by a known method using a scanning electron microscope (SEM), and taking the arithmetic mean of the thicknesses of five randomly selected points in the resulting SEM image.

[0045] In one embodiment, in the electromagnetic wave shielding material described above, the degree of crosslinking of the magnetic layer is preferably 20% or more from the viewpoint of improving the heat resistance of the electromagnetic wave shielding material, and is more preferably 30% or more, 40% or more, 50% or more, and 60% or more in that order. The degree of crosslinking can be, for example, 100% or less, less than 100%, 98% or less, 96% or less, 93% or less, or 90% or less.

[0046] In the present invention and this specification, the degree of crosslinking of the magnetic layer is a value determined by the following method. The proportion of the binder component of the magnetic layer is determined by TG / DTA (Thermogravimetry / Differential Thermal Analysis). Specifically, in a TG / DTA (thermogravimetric differential thermal analysis) apparatus, a sample taken from the magnetic layer to be measured is measured under the conditions of a measurement temperature range of 23°C to 600°C and a heating rate of 10°C / min, and the mass loss % at 600°C is taken as the proportion of the binder component (unit: mass%). The sample taken from the magnetic layer to be measured (70 mg) and 7 ml of tetrahydrofuran (THF) are added to a container whose mass in its empty state has been measured, and the entire sample is immersed in THF for 12 hours at room temperature. In the present invention and this specification, "room temperature" means 20 to 25°C. Subsequently, the contents of the container are stirred for 30 minutes at room temperature using a mix rotor. Then, the supernatant is removed while the THF-insoluble components in the container are attracted to the bottom of the container with a magnet. Next, 7 ml of acetone is added to the container, and the contents are stirred for 30 minutes at room temperature using a mix rotor. Then, the supernatant is removed while the acetone-insoluble components in the container are attracted to the bottom of the container with a magnet. After that, the container is vacuum dried for 1 hour in a vacuum dryer with an internal atmosphere temperature of 80°C, and the mass of the container is measured. The mass obtained by subtracting the mass of the empty container from the mass measured in this way is taken as the mass of the solvent-insoluble components. Using the mass of the solvent-insoluble components obtained in this way and the value of the binder component of the magnetic layer obtained by TG / DTA measurement (unit: mass %), the degree of crosslinking is calculated from the following formula: Degree of crosslinking (%) = [1 - {(Mass of the sample to be measured (70 mg) - Mass of the solvent-insoluble components) / Mass of the binder component of the sample to be measured}] × 100

[0047] <Adjacent Layers> The magnetic layer contained in the electromagnetic wave shielding material, in which the D90 of the magnetic particles is 1500 μm or less, is in direct contact with the adjacent layer on one surface side and / or the other surface side. Having a D90 of 1500 μm or less for the magnetic particles contained in the magnetic layer can contribute to improving the adhesion between this magnetic layer and the adjacent layer.

[0048] One form of the adjacent layer is a resin-containing layer. The "resin-containing layer" is one or more resin-containing layers. Another form of the adjacent layer is a metal layer. When the adjacent layer includes a resin-containing layer and / or a metal layer, the electromagnetic shielding material may further include one or more resin-containing layers and / or one or more metal layers at positions other than the adjacent layers.

[0049] The resin-containing layer and the metal layer will be explained in detail below.

[0050] <Resin-containing layer> (Adhesive layer) An adhesive layer can be considered as one form of the resin-containing layer. In the present invention and this specification, "adhesive layer" refers to a layer that has tackiness on its surface at room temperature. With respect to tackiness, "room temperature" refers to 23°C. Such a layer adheres to an object by its adhesive force when it comes into contact with the object. Tackiness generally refers to the property of exhibiting adhesive force in a short time after contact with an object with very light force. In the present invention and this specification, "having tackiness" means that the result in the inclined ball tack test specified in JIS Z 0237:2009 (measurement environment: temperature 23°C, relative humidity 50%) is No. 1 to No. 32. If other layers are laminated on the surface of the adhesive layer, for example, the surface of the adhesive layer exposed by peeling off the other layers can be subjected to the above test. If other layers are laminated on one surface and the other surface of the adhesive layer, the other layers on either surface can be peeled off.

[0051] As the adhesive layer, a film can be used which has been processed into shape by coating it with an adhesive-forming composition containing an adhesive such as an acrylic adhesive, a rubber adhesive, a silicone adhesive, or a urethane adhesive. The adhesive-forming composition can be applied, for example, to a support. The application can be carried out using known application equipment such as a blade coater or a die coater. The application can be carried out in a so-called roll-to-roll manner or in a batch manner. Examples of support materials to which the adhesive-forming composition is applied include films of various resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN) and other polyesters, polycarbonate (PC), polymethyl methacrylate (PMMA) and other acrylics, cyclic polyolefins, triacetylcellulose (TAC), polyether sulfide (PES), polyether ketone, and polyimide. As the support material, a support material can be used in which the surface to which the adhesive-forming composition is applied (the surface to be coated) has been subjected to a release treatment by a known method. One form of release treatment is the formation of a release layer. Alternatively, commercially available release-treated resin films can be used as the support material. By using a support whose surface to be coated has been subjected to a release treatment, the adhesive layer and the support can be easily separated after film formation. The adhesive layer can be formed by coating the surface to be coated with an adhesive layer-forming composition in which the adhesive is dissolved and / or dispersed in a solvent and drying it. Alternatively, an adhesive tape containing an adhesive layer can be used. As an adhesive tape, for example, double-sided tape can be used. Double-sided tape has adhesive layers on both sides of the support. In addition, an adhesive tape having an adhesive layer on one side of the support can also be used. Examples of supports include films, nonwoven fabrics, and paper made of various resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), acrylics such as polymethyl methacrylate (PMMA), cyclic polyolefins, triacetylcellulose (TAC), polyether sulfide (PES), polyether ketone, and polyimide.As adhesive tapes having an adhesive layer on one or both sides of the support, commercially available products can be used, and adhesive tapes manufactured by known methods can also be used.

[0052] The thickness of the adhesive layer is not particularly limited; the thickness of each layer can be, for example, 1 μm or more and 30 μm or less.

[0053] (Adhesive Layer) An adhesive layer can also be considered as one form of the resin-containing layer. In the present invention and this specification, "adhesive layer" refers to a layer in which a liquid or gel-like adhesive solidifies after contact with an adherend through a change in state such as drying and curing, and at that time exhibits adhesion to the adherend through an anchoring effect, physical interaction, or the formation of chemical bonds. In one form, the adhesive layer may be a layer that does not have tackiness on its surface at room temperature. The adhesive contains a resin that solidifies after drying or curing. Examples of such resins include vinyl acetate resin, ethylene vinyl acetate resin, epoxy resin, cyanoacrylate resin, acrylic resin, polyurethane resin, chloroprene rubber, styrene butadiene rubber, etc. These resins may be liquid or gel-like in nature, or a solid resin may dissolve in a solvent to become liquid or gel-like. Examples of solvents contained in adhesives include water, ketone-based solvents such as acetone, methyl ethyl ketone, and cyclohexanone; acetic acid ester-based solvents such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; carbitols such as cellosolve and butyl carbitol; aromatic hydrocarbon-based solvents such as toluene and xylene; amide-based solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; alcohol-based solvents such as ethanol, methanol, and propanol; and halogen-based solvents such as dichloromethane, trichloroethylene, and dichlorofluoroethane.

[0054] The thickness of the adhesive layer is not particularly limited; the thickness of each layer can be, for example, 1 μm or more and 30 μm or less.

[0055] (Coating Layer) A coating layer can also be considered as one form of the resin-containing layer. In the present invention and this specification, "coating layer" refers to a layer in which a liquid or gel-like coating agent solidifies after contact with an adherend through a change in state such as drying and curing, exhibiting water repellency, oil repellency, chemical resistance, abrasion resistance, etc., and contributing to suppressing aging deterioration of the electromagnetic wave shielding material, such as hydrolysis of the resin contained in the magnetic layer and / or resin-containing layer, and physical damage such as scratches. In one form, the coating layer can be provided on the outermost layer of the electromagnetic wave shielding material. The coating agent contains a resin that solidifies after drying or curing. Examples of such resins include silicone resins, fluororesins, polyolefin resins, polyacetal resins, epoxy resins, acrylic resins, polyurethane resins, polyamide resins, polyimide resins, polyester resins, polyphenylene ether resins, polyphenylene sulfide resins, polyetherimide resins, and polycarbonate resins. These resins may be liquid or gel-like in nature. Alternatively, the solid resin may dissolve in the solvent to become liquid or gel-like. Examples of solvents included in the coating agent include water, ketone-based solvents such as acetone, methyl ethyl ketone, and cyclohexanone; acetic acid ester-based solvents such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; carbitols such as cellosolve and butyl carbitol; aromatic hydrocarbon-based solvents such as toluene and xylene; amide-based solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; alcohol-based solvents such as ethanol, methanol, and propanol; and halogen-based solvents such as dichloromethane, trichloroethylene, and dichlorofluoroethane.

[0056] The thickness of the coating layer is not particularly limited; the thickness of each layer can be, for example, 1 μm or more and 10 μm or less.

[0057] It is also possible to cover the edges of the electromagnetic shielding material with a coating agent. This helps to prevent the intrusion of moisture, oil, chemicals, and mechanical damage from the edges.

[0058] (Resin Layer) As one form of the resin-containing layer, a resin layer can also be mentioned. In the present invention and this specification, "resin layer" refers to a resin film formed from a thermoplastic resin such as a synthetic resin, wherein the resin film has a film-like structure on its own and does not tack at room temperature. Examples of thermoplastic resins contained in the resin film include polyethylene (PE) resin, polypropylene (PP) resin, polyvinyl chloride (PVC) resin, polystyrene (PS) resin, vinyl acetate resin, polyurethane resin, polyvinyl alcohol resin, ethylene vinyl acetate resin, styrene-butadiene rubber, acrylonitrile-butadiene rubber, silicone rubber, olefin-based elastomer (PP), styrene-based elastomer, ABS (acrylonitrile-butadiene-styrene) resin, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polycarbonate (PC) resin, acrylic resins such as polymethyl methacrylate (PMMA), cyclic polyolefins, triacetylcellulose (TAC), and various other resins.

[0059] The resin layer can be bonded to a metal layer or a magnetic layer via an adhesive or bonding layer. Furthermore, since the resin layer contains a thermoplastic resin, it has the property of softening when heated. When pressed against an object while heated, it flows and conforms to minute irregularities on the surface of the object, exhibiting adhesive force through an anchoring effect. The bonded state can then be maintained upon cooling. Therefore, in one embodiment, the resin layer can be bonded to other layers without the need for an adhesive or bonding layer.

[0060] The thickness of the resin layer is preferably 10 μm or more, and more preferably 12 μm or more, as a thickness per resin layer. The thickness of the resin layer is preferably 250 μm or less, more preferably 230 μm or less, even more preferably 210 μm or less, and even more preferably 190 μm or less, as a thickness per resin layer.

[0061] <Metal Layer> The electromagnetic wave shielding material described above may include one or more metal layers. In one embodiment, the electromagnetic wave shielding material may have a magnetic layer between two metal layers, the magnetic particles having a D90 of 1500 μm or less. It is presumed that having a multilayer structure in which a magnetic layer is sandwiched between two metal layers is preferable for improving the electromagnetic wave shielding performance of the electromagnetic wave shielding material, particularly its shielding performance against magnetic fields. In one embodiment, in a multilayer structure in which a magnetic layer is sandwiched between two metal layers, one or more other layers, including at least an adjacent layer, may be interposed between one or both of the two metal layers and the magnetic layer. For example, an adjacent layer (or one or more other layers) may be located between each of the two metal layers and the magnetic layer. The adjacent layer and other layers here may be, for example, resin layers. In another embodiment, in a multilayer structure in which a magnetic layer is sandwiched between two metal layers, one or both of the two metal layers may be adjacent layers (i.e., layers in direct contact with the magnetic layer).

[0062] In the present invention and this specification, "metal layer" means a layer containing a metal. The metal layer may be a layer containing one or more metals, such as a pure metal consisting of a single metal element, an alloy of two or more metal elements, or an alloy of one or more metal elements and one or more nonmetal elements.

[0063] If the electromagnetic shielding material has a multilayer structure in which a magnetic layer is sandwiched between two metal layers, the electromagnetic shielding material may contain one or more such multilayer structures, or two or more. That is, the electromagnetic shielding material may contain at least two metal layers, three or more metal layers, at least one magnetic layer, or two or more magnetic layers. In one embodiment, the two or more metal layers included in the electromagnetic shielding material may have the same composition and thickness, and in another embodiment, they may have different compositions and / or thicknesses. This is also true when the electromagnetic shielding material includes two or more magnetic layers, and when other layers, such as the resin-containing layers described above, are included in two or more layers in the electromagnetic shielding material.

[0064] The metal layer contained in the electromagnetic shielding material described above may be a layer containing one or more metals selected from the group consisting of various pure metals and various alloys. The metal layer can exert an attenuation effect in the electromagnetic shielding material. This is preferable from the viewpoint of improving the shielding performance of the electromagnetic shielding material. The attenuation effect is greater the larger the propagation constant, and the propagation constant is greater the higher the electrical conductivity, so it is preferable that the metal layer contains a metal element with high electrical conductivity. From this viewpoint, it is preferable that the metal layer contains a pure metal of Ag, Cu, Au, or Al, or an alloy containing any of these as the main component. A pure metal is a metal consisting of a single metal element and may contain trace amounts of impurities. Generally, a metal consisting of a single metal element with a purity of 99.0% or more is called a pure metal. Purity is based on mass. An alloy is generally a pure metal with one or more metal elements or non-metal elements added to adjust its composition for purposes such as corrosion prevention and strength improvement. The main component in an alloy is the component with the highest proportion by mass, and can be, for example, a component that accounts for 80.0% by mass or more (for example, 99.8% by mass or less) in the alloy. From an economic standpoint, pure metals of Cu or Al, or alloys mainly composed of Cu or Al, are preferred, and from the standpoint of high electrical conductivity, pure metals of Cu or alloys mainly composed of Cu are more preferred.

[0065] The purity of the metal in the metal layer, i.e., the metal content in the metal layer, can be 99.0% by mass or more, 99.5% by mass or more, or 99.8% by mass or more, based on the total mass of the metal layer. Unless otherwise specified, the metal content in the metal layer refers to the content on a mass basis. For example, a sheet of pure metal or alloy can be used as the metal layer. For example, a commercially available metal foil or a metal foil manufactured by a known method can be used as the metal layer. For pure copper, sheets of various thicknesses (so-called copper foil) are commercially available. For example, such copper foil can be used as the metal layer. Copper foil includes electrolytic copper foil obtained by depositing copper foil on the cathode by electroplating, and rolled copper foil obtained by applying heat and pressure to an ingot and stretching it thinly. Either type of copper foil can be used as the metal layer of the electromagnetic shielding material described above. Also, for example, sheets of aluminum (so-called aluminum foil) of various thicknesses are commercially available. For example, such aluminum foil can be used as the metal layer.

[0066] From the viewpoint of economic efficiency, high electrical conductivity, and weight reduction of electromagnetic wave shielding material, the metal layer is preferably a metal layer containing a metal selected from the group consisting of Al, Mg, and Cu, and more preferably a layer containing a metal selected from the group consisting of Al, Mg, and Cu as its main component. The main component of a metal layer is the component with the highest proportion by mass. In a layer containing a metal selected from the group consisting of Al, Mg, and Cu as its main component, Al, Mg, or Cu is the component with the highest proportion by mass in this layer. Such a layer may contain only one, two, or three metals from Al, Mg, and Cu. From one or more of the above viewpoints, the metal layer is more preferably a metal layer with a metal content of 80.0% by mass or more of the metal selected from the group consisting of Al, Mg, and Cu, and even more preferably a metal layer with a metal content of 90.0% by mass or more of the metal selected from the group consisting of Al, Mg, and Cu. A metal layer containing at least Al from among Al, Mg, and Cu may have an Al content of 80.0% by mass or more, or an Al content of 90.0% by mass or more. A metal layer containing at least Mg from among Al, Mg, and Cu may have an Mg content of 80.0% by mass or more, or an Mg content of 90.0% by mass or more. A metal layer containing at least Cu from among Al, Mg, and Cu may have a Cu content of 80.0% by mass or more, or a Cu content of 90.0% by mass or more. The content of the metal selected from the group consisting of Al, Mg, and Cu, the Al content, the Mg content, and the Cu content can each be, for example, 100% by mass or less, or 99.9% by mass or less. The content of the metal selected from the group consisting of Al, Mg, and Cu, the Al content, the Mg content, and the Cu content are each percentages of the total mass of the metal layer.

[0067] Regarding the thickness of the metal layer, from the viewpoint of further improving the processability of the metal layer and the shielding performance of the electromagnetic wave shielding material, it is preferable that the thickness per layer be 4 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more. On the other hand, from the viewpoint of the processability of the metal layer, it is preferable that the thickness per layer be 200 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less.

[0068] In one embodiment, the electromagnetic shielding material may have one or both of its outermost layers as metal layers. This may contribute to the electromagnetic shielding material exhibiting high shielding performance against magnetic field waves in the low-frequency range of approximately 100 kHz to 1 MHz. Furthermore, having at least one of the outermost layers of the electromagnetic shielding material as a metal layer may also contribute to suppressing edge delamination in molded products obtained by molding. In one embodiment, one or both of the outermost layers of the electromagnetic shielding material may be metal layers that sandwich a magnetic layer together with other metal layers.

[0069] <Specific Examples of Layer Configuration> The total number of magnetic layers in the electromagnetic shielding material is one or more, and may be one, two or more, or for example, four or fewer. When the electromagnetic shielding material includes two or more magnetic layers, it is preferable that the D90 of the magnetic particles in some or all of the two or more magnetic layers is 1500 μm or less, and that the D90 of the magnetic particles in all layers is 1500 μm or less. The electromagnetic shielding material may include, for example, a total of 1 to 12 resin-containing layers. The total number of resin layers in the electromagnetic shielding material (preferably resin layers having the thickness described above) may be, for example, one to four. The total number of layers selected from the group consisting of adhesive layers and bonding layers in the electromagnetic shielding material may be, for example, one to four or one to eight. The total number of metal layers in the electromagnetic shielding material is zero or one or more, and may be two or more, for example, two to five.

[0070] In one embodiment, a multilayer structure in which a magnetic layer is sandwiched between two metal layers allows the magnetic layer to be in direct contact with both metal layers. In this case, specific examples of the layer configuration of the electromagnetic shielding material can be given below. Example A1: "metal layer / magnetic layer / metal layer" Example A2: "metal layer / magnetic layer / metal layer / magnetic layer / metal layer" Example A3: "metal layer / magnetic layer / metal layer / magnetic layer / metal layer / magnetic layer / metal layer / metal layer" In an electromagnetic shielding material that includes two or more multilayer structures having a magnetic layer between two metal layers, for example, as in Example A2 and Example A3, the metal layer sandwiching the magnetic layer in one multilayer structure can also be the metal layer sandwiching the magnetic layer in another multilayer structure. In the electromagnetic shielding material, the total number of multilayer structures having a magnetic layer between two metal layers can be, for example, one to four. The total number of the above multilayer structures is one in Example A1, two in Example A2, and three in Example A3. It is preferable that the total number of the above-mentioned multilayer structures be two or more (for example, two, three, or four) from the viewpoint of further improving the shielding performance of the electromagnetic wave shielding material. In the above, the symbol " / " means that the layer described to the left of this symbol and the layer described to the right are in direct contact without any other layers in between. This point is also the same in the following description unless otherwise specified.

[0071] In another embodiment, a multilayer structure having a magnetic layer between two metal layers may have one or more resin-containing layers between one or both of the two metal layers and the magnetic layer. In the above multilayer structure, one of the two metal layers may be adjacent to the magnetic layer without any other layers in between, and one or more resin-containing layers may be between the other metal layer and the magnetic layer. Alternatively, the above multilayer structure may also have one or more resin-containing layers between each of the two metal layers and the magnetic layer.

[0072] The above multilayer structure may include an adhesive layer and / or bonding layer between the resin layer and the metal layer. In one embodiment, the adhesive layer and / or bonding layer may be included between the resin layer and the magnetic layer in the above multilayer structure. In another embodiment, the resin layer and the magnetic layer may be in direct contact with each other in the above multilayer structure. That is, the resin layer and the magnetic layer may be adjacent to each other without any other layers in between.

[0073] Examples of the arrangement of the "magnetic layer," "metal layer," "resin layer," and "adhesive layer or bonding layer" in the electromagnetic shielding material described above include the following. In the following examples, the "adhesive layer" may include a support, and the "adhesive layer" may be an adhesive tape having adhesive layers on one or both sides of the support. For example, as in Example B3, a metal layer sandwiching one magnetic layer may also be a metal layer sandwiching another magnetic layer. For example, in Example B3, metal layer 2 is one of the two metal layers sandwiching magnetic layer 1, and is also the other of the two metal layers sandwiching magnetic layer 2. Also, in Example B3, one outermost layer of the electromagnetic shielding material is metal layer 1 that sandwiches magnetic layer 1 together with metal layer 2, and the other outermost layer of the electromagnetic shielding material is metal layer 3 that sandwiches magnetic layer 2 together with metal layer 2. Example B1: "Metal layer 1 / Adhesive layer 1 or adhesive layer 1 / Resin layer 1 / Magnetic layer 1 / Resin layer 2 / Adhesive layer 2 or adhesive layer 2 / Metal layer 2" Example B2: "Metal layer 1 / Adhesive layer 1 or adhesive layer 1 / Resin layer 1 / Magnetic layer 1 / Metal layer 2 / Adhesive layer 2 or adhesive layer 2 / Resin layer 2" Example B3: "Metal layer 1 / Adhesive layer 1 or adhesive layer 1 / Resin layer 1 / Magnetic layer 1 / Resin layer 2 / Adhesive layer 2 or adhesive layer 2 / Metal layer 2 / Adhesive layer 3 or adhesive layer 3 / Resin layer 3 / Magnetic layer 2 / Resin layer 4 / Adhesive layer 4 or adhesive layer 4 / Metal layer 3" Example B4: "Metal layer 1 / Adhesive layer 1 or adhesive layer 1 / Resin layer 1 / Magnetic layer 1 / Metal layer 2 / Adhesive layer 2 or adhesive layer 2 / Resin layer 2 / Magnetic layer 2 / Resin layer 3 / Adhesive layer 3 or adhesive layer 3 / Metal layer 3" Example B5: "Metal layer 1 / Adhesive layer 1 or adhesive layer 1 / Resin layer 1 / Magnetic layer 1 / Metal layer 2 / Adhesive layer 2 or adhesive layer 2 / Resin layer 2 / Magnetic layer 2 / Metal layer 3 / Adhesive layer 3 or adhesive layer 3 / Resin layer 3" Example B6: "Metal layer 1 / Adhesive layer 1 or adhesive layer 1 / Resin layer 1 / Magnetic layer 1 / Metal layer 2 / Magnetic layer 2 / Resin layer 2 / Adhesive layer 2 or adhesive layer 2 / Metal layer 3" Example B7: "Metal layer 1 / Adhesive layer 1 or adhesive layer 1 / Resin layer 1 / Magnetic layer 1 / Resin layer 2 / Adhesive layer 2 or adhesive layer 2 / Metal layer 2 / Magnetic layer 2 / Resin layer 3 / Adhesive layer 3 or adhesive layer 3 / Metal layer 3" Example B9: "Resin layer 1 / Adhesive layer 1 or bonding layer 1 / Metal layer 1 / Magnetic layer 1 / Metal layer 2 / Adhesive layer 2 or bonding layer 2 / Resin layer 2"

[0074] <Method for Manufacturing Electromagnetic Wave Shielding Material> (Method for Forming a Magnetic Layer) The magnetic layer described above can be produced, for example, by applying a magnetic layer-forming composition and drying the resulting coating layer. The magnetic layer-forming composition may contain the components described above and may optionally contain one or more solvents. Examples of solvents include various organic solvents, such as ketone solvents like acetone, methyl ethyl ketone, and cyclohexanone; acetic acid ester solvents like ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; carbitols like cellosolve and butyl carbitol; aromatic hydrocarbon solvents like toluene and xylene; and amide solvents like dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. One solvent selected considering the solubility of the components used in preparing the magnetic layer-forming composition, or two or more solvents mixed in any ratio, can be used. The solvent content of the magnetic layer-forming composition is not particularly limited and should be determined considering the coatability of the magnetic layer-forming composition.

[0075] A composition for forming a magnetic layer can be prepared by mixing various components sequentially or simultaneously in any order. Furthermore, if necessary, dispersion can be performed using known dispersers such as ball mills, bead mills, sand mills, and roll mills, and / or stirring can be performed using known stirrers such as shaking stirrers.

[0076] The magnetic layer-forming composition can be applied, for example, to a support. The application can be carried out using known coating equipment such as a blade coater or die coater. The application can be performed using a so-called roll-to-roll method or a batch method.

[0077] Examples of supports to which the magnetic layer-forming composition is applied include films of various resins such as polyester (PET), polyethylene terephthalate (PEN), polycarbonate (PC), acrylic (PMMA), cyclic polyolefins, triacetylcellulose (TAC), polyether sulfide (PES), polyether ketone, and polyimide. For these resin films, refer to paragraphs 0081 to 0086 of Japanese Patent Application Publication No. 2015-187260. As the support, a support that has been subjected to a release treatment by a known method on the surface to which the magnetic layer-forming composition is applied (the surface to be coated) can be used. One form of the release treatment is the formation of a release layer. For the release layer, refer to paragraph 0084 of Japanese Patent Application Publication No. 2015-187260. Alternatively, a commercially available pre-released resin film can be used as the support. By using a support with a release treatment on the surface to be coated, the magnetic layer and the support can be easily separated after film formation.

[0078] The magnetic layer-forming composition can also be applied to the surface of a metal layer or a resin-containing layer. For example, the magnetic layer-forming composition can be applied to the surface of a metal layer or a resin-containing layer, and the magnetic layer can be subjected to the pressure treatment described later as necessary. As an example, two "magnetic layer / metal layer" substructures can be pressed together with the magnetic layer sides facing each other by applying pressure and heat, thereby producing an electromagnetic wave shielding material having the layer configuration of Example A1 "metal layer / magnetic layer / metal layer" described above.

[0079] The coating layer formed by applying the magnetic layer-forming composition can be dried by known methods such as heating or blowing hot air. The drying process can be carried out under conditions that allow the solvent contained in the magnetic layer-forming composition to volatilize. For example, the drying process can be carried out in a heated atmosphere with an ambient temperature of 80 to 150°C for 1 minute to 2 hours.

[0080] (Pressurization of the magnetic layer) The magnetic layer can also be subjected to pressure treatment after film formation. By subjecting the magnetic layer to pressure treatment, the density of magnetic particles within the magnetic layer can be increased.

[0081] Pressurization can be performed by applying pressure in the thickness direction of the magnetic layer using a plate press, roll press, etc. A plate press places the object to be pressed between two flat press plates positioned vertically, and applies pressure to the object by bringing the two press plates together using mechanical or hydraulic pressure. A roll press passes the object to be pressed between rotating pressure rolls positioned vertically, and applies pressure by applying mechanical or hydraulic pressure to the pressure rolls during this process, or by making the distance between the pressure rolls smaller than the thickness of the object to be pressed.

[0082] The pressure during pressurization is, for example, 1 to 50 N (Newtons) / mm in the case of a plate press. ２ This can be done, and in the case of a roll press machine, it can be 20 to 400 N / mm ２This can be done. However, the pressure during pressurization is not particularly limited and can be set arbitrarily. The pressurization time can be set arbitrarily. When using a plate press, for example, it is 5 seconds to 30 minutes. When using a roll press, the pressurization time can be controlled by the conveying speed of the object to be pressed, for example, the conveying speed is 10 cm / min to 200 m / min. The material of the press plate and pressurization roll can be arbitrarily selected from metal, ceramics, plastic, rubber, etc. During pressurization, it is also possible to apply heat to both the upper and lower press plates of a plate press or one side of the upper and lower rolls of a roll press, and then apply pressure. Heating can soften the magnetic layer, thereby obtaining a high compression effect when pressure is applied. The temperature during heating can be set arbitrarily, for example, between 50°C and 200°C. The above-mentioned temperature during heating can be the internal temperature of the press plate or roll. Such a temperature can be measured by a thermometer installed inside the press plate or roll. After heating and pressing in a plate press, the magnetic layer can be removed by separating the press plates while they are still hot, for example. Alternatively, the press plates can be cooled by water cooling, air cooling, or other methods while maintaining pressure, and then separated to remove the magnetic layer. In a roll press, the magnetic layer can be cooled by water cooling, air cooling, or other methods immediately after pressing. It is also possible to repeat the pressing process two or more times. If the magnetic layer is formed on a release film, the pressing process can be performed, for example, while the magnetic layer is laminated on the release film. Alternatively, the magnetic layer can be peeled off the release film and pressed as a single layer.

[0083] (Bonding of various layers) Adhesive layers or bonding layers can be used to bond various layers. The adhesive layers and bonding layers are as described above. In addition, in the electromagnetic shielding material described above, two adjacent layers can be bonded together by applying pressure and heat, for example. A plate press, a roll press, etc. can be used for bonding. In the bonding process, the magnetic layer softens and contact with the surface of the adjacent layer is promoted, so that the magnetic layer and the adjacent layer can be bonded together without the interposition of other layers. The pressure during bonding can be set arbitrarily. In the case of a plate press, for example, 1 to 50 N (Newtons) / mm ２ In the case of a roll press, for example, the linear pressure is 20 to 400 N / mm. The pressing time during crimping can be set arbitrarily. When using a plate press, for example, it is 5 seconds to 30 minutes. When using a roll press, it can be controlled by the conveying speed of the object to be pressed, for example, the conveying speed is 10 cm / min to 200 m / min. The temperature during crimping can be selected arbitrarily, for example, between 20°C and 200°C. The above temperature during crimping can be, for example, the internal temperature of the press plate or roll.

[0084] The electromagnetic shielding material described above can be incorporated into electronic components or electronic devices in any shape. The electromagnetic shielding material can be in sheet form, and its size is not particularly limited. In this invention and specification, "sheet" is synonymous with "film". Furthermore, the electromagnetic shielding material can be a three-dimensional molded product obtained by three-dimensionally molding a sheet-like electromagnetic shielding material, or it can be a sheet-like electromagnetic shielding material for three-dimensional molding. Various molding methods such as die press molding, vacuum forming, and pressure forming can be used as the three-dimensional molding method. Regarding the molding method, molding that is performed without heating the object to be molded and / or the mold, or by heating without raising the temperature too much, is generally called cold forming. In one embodiment, the electromagnetic shielding material described above can be molded by cold forming such as deep drawing or stretching. Deep drawing is a molding method in which a sheet-like object to be molded is pressed using a pair of female and male molds to form a bottomed container of various shapes such as a cylinder, a rectangular tube, or a cone. In contrast, stretch molding is a method of forming a molded product from a sheet-like material in which a curved surface protrudes from a flat surface. Stretch molding can be performed using only a male mold, without a female mold. Deep drawing is broadly classified into deep drawing and shallow drawing. Shallow drawing produces molded products with shallow depths, while deep drawing produces molded products with greater depths (for example, deeper than the diameter of a cylinder or cone, or the length of one side of a pyramid). For three-dimensional molding methods, known techniques can be applied.

[0085] [Electronic Components] One aspect of the present invention relates to an electronic component including the above-mentioned electromagnetic shielding material. Examples of the above-mentioned electronic component include various electronic components such as electronic components included in electronic devices such as mobile phones, personal digital assistants, and medical devices, semiconductor elements, capacitors, coils, and cables. The above-mentioned electromagnetic shielding material can, for example, be three-dimensionally molded into any shape according to the shape of the electronic component and placed inside the electronic component, or it can be three-dimensionally molded into the shape of a cover material that covers the outside of the electronic component and placed as a cover material. Alternatively, it can be three-dimensionally molded into a cylindrical shape and placed as a cover material that covers the outside of a cable.

[0086] [Electronic Devices] One aspect of the present invention relates to electronic devices including the electromagnetic shielding material described above. Examples of such electronic devices include mobile phones, personal digital assistants, medical devices, electronic devices including various electronic components such as semiconductor elements, capacitors, coils, and cables, and electronic devices in which electronic components are mounted on a circuit board. Such electronic devices may include the electromagnetic shielding material as a component of the electronic components contained in them. Furthermore, the electromagnetic shielding material can be placed inside the electronic device, or as a cover material covering the outside of the electronic device. Alternatively, it can be formed into a cylindrical shape and used as a cover material covering the outside of a cable.

[0087] One example of how the above-mentioned electromagnetic shielding material can be used is to cover a semiconductor package on a printed circuit board with the electromagnetic shielding material. For example, "Electromagnetic Shielding Technology for Semiconductor Packages" (Toshiba Review Vol. 67 No. 2 (2012) P. 8) discloses a method for obtaining a high shielding effect by performing ground wiring by electrically connecting the side vias at the edge of the package substrate to the inner surface of the electromagnetic shielding material when covering a semiconductor package with the electromagnetic shielding material. In order to perform such wiring, it is desirable that the outermost layer on the electronic component side of the electromagnetic shielding material be a metal layer. If the electromagnetic shielding material has one or both outermost layers that are metal layers, it can be suitably used when performing the above-mentioned wiring.

[0088] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the embodiments shown in the examples. Unless otherwise specified, the following steps were carried out at room temperature of 20 to 25°C.

[0089] [Unclassified Magnetic Particles] The unclassified magnetic particles listed in the table below are Sendust (trade name MFS-SUH) manufactured by MKT Corporation (Fe-Si-Al flattened particles). These magnetic particles were used in the preparation of the magnetic layer forming composition without any classification treatment.

[0090] [Classified Magnetic Particles 1] Sendust (product name MFS-SUH) manufactured by MKT Corporation was sieved through a nylon mesh with a mesh opening of 149 μm, and the magnetic particles that passed through the nylon mesh were collected and used as Classified Magnetic Particles 1 in the preparation of the composition for forming the magnetic layer.

[0091] [Classified Magnetic Particles 2] Sendust (product name MFS-SUH) manufactured by MKT Corporation was sieved through a nylon mesh with a mesh opening of 132 μm, and the magnetic particles that passed through the nylon mesh were recovered and used as classified magnetic particles 2 in the preparation of the composition for forming the magnetic layer.

[0092] [Classified Magnetic Particles 3] Sendust (product name MFS-SUH) manufactured by MKT Corporation was sieved through a nylon mesh with a mesh opening of 108 μm, and the magnetic particles that passed through the nylon mesh were collected and used as classified magnetic particles 3 in the preparation of the composition for forming the magnetic layer.

[0093] [Classified Magnetic Particles 4] Sendust (product name MFS-SUH) manufactured by MKT Corporation was sieved through a nylon mesh with a mesh opening of 70 μm, and the magnetic particles that passed through the nylon mesh were collected and used as classified magnetic particles 4 in the preparation of the composition for forming the magnetic layer.

[0094] [Classified Magnetic Particles 5] Sendust (product name MFS-SUH) manufactured by MKT Corporation was sieved through a nylon mesh with a mesh opening of 55 μm, and the magnetic particles that passed through the nylon mesh were recovered and used as classified magnetic particles 5 in the preparation of the composition for forming the magnetic layer.

[0095] [Example 1] <Preparation of composition for forming a magnetic layer (coating solution)> In a plastic bottle, Magnetic particles (see table below): 12 g Polyurethane resin (Nipporan 5120 manufactured by Tosoh Corporation, solid content concentration 30% by mass): 7.0 g Curing agent (adduct body of TDI (tolylene diisocyanate) and trimethylolpropane, Takenate D101E manufactured by Mitsui Chemicals, solid content concentration 75% by mass): 0.42 g Epoxy resin (modified epoxy resin manufactured by DIC Corporation (product name HP-A-4860, solid content concentration 100% by mass): 0.8 g Curing agent for epoxy resin (IBMI12 manufactured by Mitsubishi Chemical Corporation, solid content concentration 100% by mass): 0.02 g Cyclohexanone: 20 g The mixture was added and mixed in a shaking stirrer for 1 hour to prepare the coating solution. The magnetic layer formed using the above composition contains a urethane resin and a resin having a substructure represented by formula 1. The total resin content per 100 parts by mass of the total mass of the magnetic layer is the value shown in the table below.

[0096] <Magnetic Layer Preparation> (Deposition of Magnetic Layer) The above coating solution was applied to the peeled surface of a peeled PET film (PET75-JOL manufactured by Nipper Co., Ltd.) using a blade coater with a coating gap of 300 μm, and dried in a drying apparatus at an internal ambient temperature of 80°C for 30 minutes to form a film-like magnetic layer on the peeled PET film.

[0097] (Pressurization and heat treatment of the magnetic layer) The upper and lower press plates of a plate press (Mini Test Press manufactured by Toyo Seiki) are heated to 140°C (internal temperature of the press plates), and the magnetic layer from which the above-mentioned peeled PET film has been removed is sandwiched between two 1 mm thick Teflon® sheets and subjected to 30 N / mm² pressure. ２ The pressure was applied and held for 10 minutes. After the upper and lower press plates were cooled to 50°C (internal temperature of the press plates) while maintaining the pressure, the magnetic layer was removed from between the two Teflon® sheets. Then, in order to cause a crosslinking reaction between the resin and hardener contained in the magnetic layer, the magnetic layer was heat-treated by holding it in a drying apparatus with an internal atmosphere temperature of 60°C for 48 hours to obtain the magnetic layer. From a portion of the obtained magnetic layer, a sample for measuring the D90 of the magnetic particles and a sample for measuring the magnetic permeability, as described later, were cut out.

[0098] <Fabrication of Electromagnetic Shielding Material> Using the magnetic layer obtained above as the magnetic layer, and using aluminum foil model number A1N30-O (metal layer with an Al content of 99.0% by mass or more) manufactured by Takeuchi Metal Foil & Powder Co., Ltd. as the metal layer, a laminate was fabricated by stacking three layers, "aluminum foil (metal layer) / magnetic layer / aluminum foil (metal layer)," without interposing any other layers between adjacent layers. The upper and lower press plates of a plate press machine (large hot press TA-200-1W manufactured by Yamamoto Iron Works Co., Ltd.) were heated to 140°C (internal temperature of the press plate), and the above laminate was placed in the center of the press plate, with a load of 4.66 N / mm². ２ The aluminum foil and magnetic layer were heat-pressed together by applying pressure and holding it for 10 minutes. After the upper and lower press plates were cooled to 50°C (internal temperature of the press plates) while maintaining the pressure, the laminate was removed from the plate press. In this way, the electromagnetic wave shielding material of Example 1 was obtained.

[0099] <Measurement of Thickness of Each Layer> The cross-section of the electromagnetic shielding material of Example 1 was processed to expose its cross-section using the following method. The electromagnetic shielding material, cut to a size of 3 mm x 3 mm, was embedded in resin, and the cross-section of the electromagnetic shielding material was cut using an ion milling device (Hitachi High-Tech Corporation IM4000PLUS). The exposed cross-section of the electromagnetic shielding material was observed using a scanning electron microscope (Hitachi High-Tech Corporation SU8220) under conditions of an acceleration voltage of 2 kV and a magnification of 100x, and a backscattered electron image was obtained. Using the scale bar as a reference from the obtained image, the thickness of the magnetic layer and the thickness of each of the two metal layers were measured at five locations. The arithmetic mean of each measurement was taken as the thickness of the magnetic layer and the thickness of each metal layer. The thickness of the magnetic layer was 30 μm, and the thickness of each metal layer (aluminum foil) was 50 μm.

[0100] [Examples 2-5, Comparative Example 1] The electromagnetic shielding materials of Examples 2-5 and Comparative Example 1 were obtained by the method for producing the electromagnetic shielding material of Example 1, except that the magnetic particles shown in the table below were used instead of magnetic particle 1.

[0101] [Example 6] An electromagnetic shielding material of Example 6 was obtained by the method for manufacturing an electromagnetic shielding material of Example 4, except for the following points. Instead of the aluminum foil described above, Panac's Alpet 50-50 (a laminate made by bonding a 50 μm thick aluminum foil (metal layer with an Al content of 99.0% by mass or more) and a 50 μm thick PET film (resin layer) via a 3 μm thick adhesive layer) was used. The obtained electromagnetic shielding material has a layer structure of "aluminum foil (metal layer) / adhesive layer / resin layer (PET film) / magnetic layer / resin layer (PET film) / adhesive layer / aluminum foil (metal layer)".

[0102] [Example 7] An electromagnetic wave shielding material of Example 7 was obtained by the method for producing an electromagnetic wave shielding material of Example 4, except that the composition for forming the magnetic layer (coating liquid) was prepared as follows. The magnetic layer produced using the following coating liquid contains a urethane resin and a resin having a partial structure represented by formula 1-1. The total resin content per 100 parts by mass of the total mass of such magnetic layer is the value shown in the table below.

[0103] <Preparation of Magnetic Layer Forming Composition (Coating Solution)> The following ingredients were added to a plastic bottle: Magnetic particles (see table below): 100 g Urethane resin (urethane resin solution manufactured by Tosoh Corporation (product name: Nipponran 5120)): 53.9 g Epoxy resin (modified epoxy resin manufactured by DIC Corporation (product name: HP-A-4860)): 6.2 g Cyclohexanone: 183.2 g The mixture was mixed for 1 hour using a shaking stirrer. After the above mixing, the following ingredients were added: Curing agent (HDI (hexamethylene diisocyanate) (manufactured by Asahi Kasei Corporation, product name: Duranate TPA-100)): 2.4 g Curing accelerator (1-isobutyl-2-methylimidazole manufactured by Mitsubishi Chemical Corporation (product name: IBMI12)): 0.2 g The mixture was mixed for 10 minutes using a shaking stirrer to prepare the coating solution (magnetic layer forming composition).

[0104] [Examples 8-10] The electromagnetic shielding materials of Examples 8-10 were obtained using the method for producing electromagnetic shielding materials of Example 4, except that the total resin content per 100 parts by mass of the magnetic layer was changed as shown in the table below by reducing or increasing the amount of magnetic particles added to the above coating solution.

[0105] [Measurement of D90 of magnetic particles contained in the magnetic layer] <Extraction of magnetic particles from the magnetic layer> For each of Examples 1 to 10 and Comparative Example 1, a sample for measuring the D90 of magnetic particles was cut out from a portion of the magnetic layer obtained by the method described above. The above sample for measurement was placed in an AS ONE muffle furnace, and after raising the furnace temperature to 400°C, this temperature was maintained for 3 hours to thermally decompose the binder component. After cooling to room temperature, the residue of the sample for measurement was collected and dispersed in methyl ethyl ketone. Next, only the magnetic particles were attracted using a magnet, and the excess methyl ethyl ketone was removed with a dropper. Methyl ethyl ketone was added again, and the same magnetic particle washing operation was repeated 5 times to remove the binder component residue. After that, it was dried under reduced pressure at 80°C to obtain magnetic particles for particle size distribution measurement.

[0106] <Particle Size Distribution Measurement> The particle size distribution of the magnetic particles obtained above was measured using a laser diffraction / scattering particle size distribution analyzer (LA-960V2-Vertical (serial number RR2VKRX9) manufactured by Horiba, Ltd.). First, a methyl ethyl ketone mixture containing 0.1% by mass of magnetic particles was prepared and dispersed for 20 minutes using an IKA Vortex3 shaker to prepare a dispersion for measurement. Next, methyl ethyl ketone was placed in the glass cell (55 mm × 30 mm × 4 mm) of the above measuring device, the glass cell was sealed with a Teflon® lid, and the device was mounted horizontally for blank measurement. The measurement conditions were as follows. Refractive index R: Iron 3.5-3.800i, Methyl ethyl ketone 1.379 Refractive index B: Iron 3.5-3.800i, Methyl ethyl ketone 1.379 Particle size standard: Volume data acquisition count: 5000 times Next, the contents of the glass cell were changed to a dispersion liquid for measurement, the glass cell was placed in a measurement holder and left for 5 minutes, and then the sample was measured to obtain particle size distribution data. The particle size distribution data obtained in this way is data obtained without signal processing. From the obtained particle size distribution data, the 90% cumulative frequency diameter D90 was determined.

[0107] [Measurement of Permeability of Magnetic Layers] For each of Examples 1 to 10 and Comparative Example 1, a 28 mm x 10 mm sample was cut from a portion of the magnetic layer obtained by the method described above, and the permeability was measured using a permeability measuring device (per01, manufactured by Keycom Co., Ltd.). The permeability was determined as the real part of the complex ratio permeability (μ') at a frequency of 3 MHz (measurement temperature: 25°C). The permeability thus determined was evaluated according to the following evaluation criteria. (Evaluation Criteria) A: Permeability μ' is 100 or more B: Permeability μ' is less than 100

[0108] [Measurement of Peel Strength] The peel strength of each electromagnetic shielding material in Examples 1 to 10 and Comparative Example 1 was measured by the following method. A higher measured peel strength indicates higher adhesion between the magnetic layer and the adjacent layer. A double-sided tape No. 5015 (manufactured by Nitto Denko Corporation), with one side of the release tape peeled off in the longitudinal direction of the stainless steel plate, was attached to the center of the width direction of a stainless steel plate measuring 120 mm in length x 40 mm in width x 2 mm in thickness. A soft urethane roller No. 10840 (manufactured by Ota Seisakusho) was applied by moving it back and forth 10 times over the other side of the release film to fix it in place. The release film on the surface of the double-sided tape was peeled off, and a measurement sample cut from the electromagnetic shielding material to a size of 10 mm in width x 100 mm in length was placed on it. A soft urethane roller No. 10840 (manufactured by Ota Seisakusho) was applied by moving it back and forth 10 times to fix it in place. After being left in room temperature air for 48 hours, an incision was made in the magnetic layer position of the measurement sample to create a peel section of 10 mm in length. The sample, along with the stainless steel plate, was mounted on the standard stage attached to the VPA-H100F peel tester (manufactured by Kyowa Interface Science Co., Ltd.). A 50 μm thick polyimide film 200H (manufactured by Toray DuPont) was cut to a length of 100 mm x width of 10 mm, and one end of the polyimide film and the peeling area of ​​the shielding material were bonded together using double-sided tape No. 5015 (manufactured by Nitto Denko Corporation), cut to a length of 10 mm. The other end of the polyimide film was attached to the gripping part of the measurement unit of the peel tester, and the peel force [N / cm] was measured under the conditions of a peel angle of 90°, a peel speed of 10 mm / min, and a measurement distance of 60 mm. The average value (arithmetic mean) of the measurement results from a measurement distance of 20 mm to 50 mm was taken as the peel strength of the measurement sample. Each measurement sample was evaluated according to the following evaluation criteria based on the obtained peel strength value. (Evaluation Criteria) A: Peel strength of 3 N / cm or more B: Peel strength of 1 N / cm or more but less than 3 N / cm C: Peel strength less than 1 N / cm

[0109] [Evaluation of Shielding Performance (KEC Method)] An electromagnetic shielding material cut to a size of 15 cm x 15 cm was placed between the antennas of a KEC method evaluation device including a signal generator, amplifier, a pair of magnetic field antennas, and a spectrum analyzer. At a frequency of 100 kHz, the ratio of the received signal strength with and without the electromagnetic shielding material was determined and defined as the shielding performance. This was performed for the magnetic field antenna to determine the electromagnetic shielding performance (magnetic field shielding performance). KEC is an abbreviation for Kansai Electronics Industry Promotion Center. The shielding performance was evaluated from the values ​​obtained in this way according to the following evaluation criteria. (Evaluation Criteria) A: 23 dB or more B: Less than 23 dB

[0110] The results are shown in the table below.

[0111]

[0112]

[0113]

[0114] From these results, it can be confirmed that the electromagnetic shielding materials of Examples 1 to 10 have superior interlayer adhesion between the magnetic layer and adjacent layers compared to the electromagnetic shielding material of Comparative Example 1.

[0115] One aspect of the present invention is useful in the technical fields of various electronic components and various electronic devices.

Claims

1. An electromagnetic wave shielding material having a magnetic layer containing magnetic particles and resin, wherein the material has at least one adjacent layer in direct contact with the magnetic layer, and the 90% cumulative frequency diameter D90 obtained by measuring the particle size distribution of the magnetic particles contained in the magnetic layer is 1500 μm or less.

2. The electromagnetic wave shielding material according to claim 1, wherein the adjacent layer is located on one surface side and the other surface side of the magnetic layer.

3. The electromagnetic wave shielding material according to claim 2, wherein the adjacent layer is a metal layer.

4. The electromagnetic wave shielding material according to claim 2, wherein the adjacent layer is a resin-containing layer.

5. The electromagnetic wave shielding material according to claim 4, wherein the magnetic layer is located between two metal layers, and the adjacent resin-containing layer is located between one of the two metal layers and the magnetic layer, and between the other metal layer and the magnetic layer, respectively.

6. The electromagnetic wave shielding material according to claim 1, wherein the content of the resin in the magnetic layer is 15 parts by mass or more and 25 parts by mass or less, with respect to 100 parts by mass of the total mass of the magnetic layer.

7. The resin of the magnetic layer is a urethane resin and the following formula 1: An electromagnetic wave shielding material according to claim 1, comprising a resin having a substructure represented by and , wherein in formula 1, * represents the bonding position with an adjacent atom.

8. The adjacent layer is present on one surface side and the other surface side of the magnetic layer, the adjacent layer is a metal layer, the content of the resin in the magnetic layer is 15 parts by mass or more and 25 parts by mass or less per 100 parts by mass of the total mass of the magnetic layer, and the resin of the magnetic layer is a urethane resin and the following formula 1: An electromagnetic wave shielding material according to claim 1, comprising a resin having a substructure represented by and , wherein in formula 1, * represents the bonding position with an adjacent atom.

9. The adjacent layer is located on one surface side and the other surface side of the magnetic layer, the adjacent layer is a resin-containing layer, the magnetic layer is located between two metal layers, the resin-containing adjacent layer is located between one of the two metal layers and the magnetic layer, and between the other metal layer and the magnetic layer, the resin content in the magnetic layer is 15 parts by mass or more and 25 parts by mass or less per 100 parts by mass of the total mass of the magnetic layer, and the resin in the magnetic layer is a urethane resin and the following formula 1: An electromagnetic wave shielding material according to claim 1, comprising a resin having a substructure represented by and , wherein in formula 1, * represents the bonding position with an adjacent atom.

10. An electronic component comprising an electromagnetic shielding material according to any one of claims 1 to 9.

11. Electronic equipment comprising an electromagnetic shielding material according to any one of claims 1 to 9.

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