Electromagnetic wave shielding material, electronic component, and electronic device

Abstract

Provided is an electromagnetic wave shielding material, an electronic component including the electromagnetic wave shielding material, and an electronic device, in which at least one of the outermost layers of the electromagnetic wave shielding material is a metal layer, the electromagnetic wave shielding material has an elongation at break of 40% or more, the product of the thickness and tensile strength of the electromagnetic wave shielding material is 40 N / mm or less, and the electromagnetic wave shielding material includes one or more magnetic layers sandwiched between two metal layers.

Description

Technical Field

[0001] This invention relates to an electromagnetic wave shielding material, electronic components, and electronic devices. Background Technology

[0002] In recent years, electromagnetic wave shielding materials have attracted attention as materials used to reduce the influence of electromagnetic waves in various electronic components and electronic devices (see, for example, Patent Document 1).

[0003] Previous technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2022-91579 Summary of the Invention

[0006] The technical problem to be solved by the invention

[0007] Electromagnetic wave shielding materials (hereinafter also referred to as "shielding materials") can perform the function of shielding electromagnetic waves by reflecting electromagnetic waves incident on the shielding material and / or attenuating them inside the shielding material.

[0008] The following two properties can be listed as the desired properties for electromagnetic wave shielding materials.

[0009] First, it should provide high shielding performance against electromagnetic waves. Electromagnetic wave shielding materials with high shielding performance against electromagnetic waves can significantly reduce the impact of electromagnetic waves in electronic components and electronic devices, and are therefore preferred. In this regard, according to the inventors' research, the shielding performance of existing electromagnetic wave shielding materials against electromagnetic waves, especially against magnetic field waves in the low-frequency region of 100 kHz to 1 MHz, still needs further improvement.

[0010] Secondly, it exhibits excellent processability. Electromagnetic wave shielding materials can be processed into various shapes for assembly into electronic components or electronic devices. Excellent processability means that molded products are less prone to defects such as shape defects and breakage. Electromagnetic wave shielding materials with excellent processability can suppress the occurrence of defects such as breakage and can be molded into the desired shape, thus making them a preferred choice.

[0011] In view of the above, one aspect of the present invention aims to provide an electromagnetic wave shielding material that can provide high shielding performance for electromagnetic waves, especially for magnetic field waves in the low-frequency region of 100kHz to 1MHz, and has excellent formability.

[0012] means for solving technical problems

[0013] One aspect of the present invention is as follows.

[0014] [1] An electromagnetic wave shielding material, wherein,

[0015] At least one outermost layer of an electromagnetic wave shielding material is a metal layer.

[0016] The elongation at break of the electromagnetic wave shielding material is over 40%.

[0017] The product of the thickness and tensile strength of the electromagnetic wave shielding material is less than 40 N / mm, and

[0018] It contains one or more magnetic layers sandwiched between two metal layers.

[0019] [2] According to the electromagnetic wave shielding material described in [1], wherein,

[0020] The two outermost layers of the aforementioned electromagnetic wave shielding material are metal layers.

[0021] [3] According to the electromagnetic wave shielding material described in [1] or [2], wherein,

[0022] One or two of the outermost layers of the aforementioned electromagnetic wave shielding material are metal layers with magnetic layers sandwiched between other metal layers.

[0023] [4] The electromagnetic wave shielding material according to any one of [1] to [3], wherein,

[0024] The magnetic layer sandwiched between the two metal layers has one or more resin-containing layers between it and one or both of the two metal layers.

[0025] [5] According to the electromagnetic wave shielding material described in [4], wherein,

[0026] The resin mentioned above is a polyester resin.

[0027] [6] The electromagnetic wave shielding material according to any one of [1] to [5], wherein,

[0028] The aforementioned magnetic layer contains magnetic particles.

[0029] [7] According to the electromagnetic wave shielding material described in [6], wherein,

[0030] The aforementioned magnetic layer also contains resin.

[0031] [8] The electromagnetic wave shielding material according to any one of [1] to [7], wherein,

[0032] The thickness of the aforementioned magnetic layer is 5 μm or more and 100 μm or less.

[0033] [9] The electromagnetic wave shielding material according to any one of [1] to [8], wherein,

[0034] One or both of the two metal layers sandwiching the magnetic layer are layers containing a metal selected from the group consisting of Al, Mg and Cu as the main component.

[0035]

[10] The electromagnetic wave shielding material according to any one of [1] to [9], wherein,

[0036] The above-mentioned electromagnetic wave shielding materials have an elongation at break of 40% or more and 100% or less.

[0037]

[11] The electromagnetic wave shielding material according to any one of [1] to

[10] , wherein,

[0038] The product of the thickness and tensile strength of the aforementioned electromagnetic wave shielding material is greater than 5 N / mm and less than 40 N / mm.

[0039]

[12] According to the electromagnetic wave shielding material described in [1], wherein,

[0040] One or two of the outermost layers of the aforementioned electromagnetic wave shielding material are metal layers with magnetic layers sandwiched between other metal layers.

[0041] The magnetic layer sandwiched between the two metal layers has one or more layers containing polyester resin between it and one or both of the two metal layers.

[0042] The aforementioned magnetic layer contains magnetic particles and resin.

[0043] The thickness of the aforementioned magnetic layer is 5 μm or more and 100 μm or less.

[0044] One or both of the two metal layers sandwiching the aforementioned magnetic layer are layers containing a metal selected from the group consisting of Al, Mg, and Cu as the main component.

[0045] The above-mentioned electromagnetic wave shielding materials have an elongation at break of 40% or more and 100% or less, and

[0046] The product of the thickness and tensile strength of the aforementioned electromagnetic wave shielding material is greater than 5 N / mm and less than 40 N / mm.

[0047]

[13] An electronic component comprising any one of [1] to

[12] electromagnetic wave shielding material.

[0048]

[14] An electronic device comprising any one of [1] to

[12] electromagnetic wave shielding material.

[0049] Invention Effects

[0050] According to one aspect of the present invention, an electromagnetic wave shielding material can be provided that exhibits high shielding performance against electromagnetic waves, especially magnetic field waves in the low-frequency region of 100kHz to 1MHz, and also possesses excellent formability. Furthermore, according to one aspect of the present invention, an electronic component and electronic device incorporating the electromagnetic wave shielding material can be provided. Detailed Implementation

[0051] Electromagnetic wave shielding materials

[0052] One aspect of the present invention relates to an electromagnetic wave shielding material. At least one outermost layer of the electromagnetic wave shielding material is a metal layer, the elongation at break of the electromagnetic wave shielding material is 40% or more, the product of the thickness and tensile strength of the electromagnetic wave shielding material is 40 N / mm or less, and the electromagnetic wave shielding material includes one or more magnetic layers sandwiched between two metal layers.

[0053] In this invention and specification, "electromagnetic wave shielding material" refers to a material capable of exhibiting 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. "Electromagnetic wave shielding material" can be a material capable of exhibiting shielding performance against one or both of 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.

[0054] In this invention and specification, "magnetism" refers to ferromagnetic property. Details regarding the magnetic layer will be described later.

[0055] In this invention and specification, the thickness of the electromagnetic wave shielding material is defined as the arithmetic mean of the thicknesses at five randomly selected locations within the material. The thickness can be measured using known measuring tools (e.g., a micrometer). The thickness of each layer within the electromagnetic wave shielding material is defined as the arithmetic mean of the thicknesses at five randomly selected locations within the resulting SEM image, obtained by photographing a cross-section exposed using known methods with a scanning electron microscope (SEM).

[0056] In this invention and this specification, the elongation at break and tensile strength of the electromagnetic wave shielding material are determined by the following methods.

[0057] A 50mm long × 10mm wide test sheet is cut from the electromagnetic wave shielding material of the test object. This test sheet is mounted on a tensile testing machine, and a tensile test is performed under the following test conditions. For example, a Tensilon universal testing machine (RTF-1310) manufactured by A&D Company, Limited can be used. To acclimatize the test sheet to the test environment, it is placed in the test environment for at least 15 minutes before being mounted on the tensile testing machine and subjected to a tensile test. Regarding the elongation at break, the longest tensile length of the test sheet stretched during the tensile test (i.e., the elongation displacement in the length direction at the point where at least one layer of the test sheet breaks) is set as L, and calculated using the formula: elongation at break [unit: %] = 100 × L / clamp spacing. Whether at least one layer breaks can be determined by stress reduction in the stress-strain curve, visual inspection, etc. "Tensile strength [unit: N / mm]" 2 The value is determined as the maximum stress obtained in the tensile test.

[0058] (Measurement conditions)

[0059] Chuck spacing: 25mm

[0060] Measurement environment: temperature 23℃, relative humidity 50%

[0061] Force sensor: 500 N (Newtons)

[0062] Stretching speed: 1mm / minute

[0063] Tension direction: length direction

[0064] The inventors speculate on the above-mentioned electromagnetic wave shielding material as follows.

[0065] An elongation at break of 40% or more and a product of thickness and tensile strength of 40 N / mm or less may contribute to the excellent processability of the aforementioned electromagnetic wave shielding material. Specifically, an elongation at break of 40% or more may help suppress breakage in the molded article obtained through molding. A product of thickness and tensile strength of 40 N / mm or less may help obtain the desired shape of the molded article through molding, i.e., help suppress shape defects in the molded article.

[0066] The aforementioned electromagnetic wave shielding material has a multilayer structure with a magnetic layer sandwiched between two metal layers, and at least one outermost layer of the electromagnetic wave shielding material is a metal layer. This may help the electromagnetic wave shielding material to exert high shielding performance against magnetic field waves in the low-frequency region of 100kHz to 1MHz. Furthermore, the fact that at least one outermost layer of the electromagnetic wave shielding material is a metal layer may help suppress edge peeling in the molded product obtained through molding processing.

[0067] However, the present invention is not limited to the speculative content described in this specification.

[0068] The electromagnetic wave shielding materials described above will be explained in further detail below.

[0069] Elongation at break

[0070] From the viewpoint of improving processability, the elongation at break of the aforementioned electromagnetic wave shielding material is 40% or more, preferably 43% or more, and more preferably 46% or more. The elongation at break of the aforementioned electromagnetic wave shielding material can, for example, be 100% or less, 95% or less, or 90% or less. From the viewpoint of further suppressing breakage in the molded article obtained through molding, a higher elongation at break is more preferable; therefore, the elongation at break of the aforementioned electromagnetic wave shielding material can also exceed the values ​​exemplified here. The method for controlling the elongation at break of the electromagnetic wave shielding material will be described later.

[0071] <Product of thickness and tensile strength>

[0072] From the perspective of improving processability, the thickness [unit: mm] and tensile strength [unit: N / mm] of the aforementioned electromagnetic wave shielding material are related. 2 The product of thickness and tensile strength is 40 N / mm or less, or even 35 N / mm or less, or 30 N / mm or less. A product of thickness and tensile strength of 40 N / mm or less may help to obtain a molded article of the desired shape through molding processing, i.e., it helps to suppress shape defects in the molded article. The product of thickness and tensile strength of the aforementioned electromagnetic wave shielding material may, for example, exceed 0 N / mm, 1 N / mm or more, 5 N / mm or more, or 10 N / mm or more. From the viewpoint of further suppressing shape defects in the molded article, a smaller value for the product of thickness and tensile strength is preferred.

[0073] The thickness of the aforementioned electromagnetic wave shielding material can be, for example, 0.050 mm or more, or 0.100 mm or more, and, for example, 0.700 mm or less, or 0.600 mm or less. The tensile strength of the aforementioned electromagnetic wave shielding material can be, for example, 60 N / mm². 2 Above or 70 N / mm 2 The above, and, for example, can be 100 N / mm 2 Below or 90N / mm 2 The following applies. Where the product of the thickness and tensile strength of the electromagnetic wave shielding material is less than 40 N / mm, the thickness and tensile strength are not particularly limited. The method for controlling the tensile strength of the electromagnetic wave shielding material will be described later.

[0074] The electromagnetic wave shielding materials mentioned above will be described in more detail below.

[0075] <Magnetic Layer>

[0076] (Magnetic materials)

[0077] The magnetic layer is a layer containing magnetic material. Magnetic materials can include magnetic particles. As magnetic particles, one type selected from the group consisting of magnetic particles commonly referred to as soft magnetic particles, including metal particles and ferrite particles, or a combination of two or more types in any proportion, can be used. Metal particles typically have about 2 to 3 times the saturation magnetic flux density compared to ferrite particles; therefore, they do not magnetically saturate even under strong magnetic fields and maintain relative permeability, thus exhibiting shielding performance. Therefore, the magnetic particles contained in the magnetic layer are preferably metal particles. In this invention and this specification, a layer containing metal particles as a magnetic material corresponds to "magnetic layer".

[0078] Metal particles

[0079] Examples of metal particles used as the aforementioned magnetic materials 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 commonly referred to as iron-based amorphous alloys, Co-containing alloys commonly referred to as cobalt-based amorphous alloys, alloys commonly referred to as nanocrystalline alloys, iron, and Permund alloys (Fe-Co alloy). Among these, iron-silicon-aluminum alloys exhibit high saturation magnetic flux density and relative permeability, and are therefore preferred. In addition to the constituent elements of the metal (including alloys), the metal particles may also contain elements present in any proportion of additives that can be added at will, and / or elements present in impurities that may be unintentionally introduced during the manufacturing process of the metal particles. In the metal particles, the content of the 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 be 100% by mass, or less than 100% by mass, less than 99.9% by mass, or less than 99.0% by mass.

[0080] In one embodiment, a magnetic layer exhibiting high permeability (specifically, the real part of the complex relative permeability) is preferred. When the complex relative permeability is measured using a permeability measuring device, a real part μ' and an imaginary part μ' are typically displayed. In this invention and specification, the real part of the complex relative permeability refers to this real part μ'. Hereinafter, the real part of the complex relative permeability at 100 kHz will also be simply referred to as "permeability". Permeability can be measured using a commercially available permeability measuring device or a permeability measuring device with a known structure. From the viewpoint that electromagnetic wave shielding materials can exhibit superior shielding performance, a magnetic layer sandwiched between two metal layers is preferred to have a permeability (the real part of the complex relative permeability at 100 kHz). A magnetic layer with a real conductivity of 30 or more. More preferably, the magnetic permeability is 40 or more, further preferably 50 or more, even more preferably 60 or more, still more preferably 70 or more, even more preferably 80 or more, even more preferably 90 or more, and even more preferably 100 or more. Furthermore, the magnetic permeability can be, for example, 200 or less, 190 or less, 180 or less, 170 or less, or 160 or less, or higher than the values ​​exemplified here. From the viewpoint of further improving the shielding performance of electromagnetic wave shielding materials, the higher the magnetic permeability, the more preferred.

[0081] From the viewpoint of forming a magnetic layer exhibiting high permeability, the aforementioned magnetic particles are preferably flat-shaped particles. By arranging the long side direction of the flat-shaped particles to be more parallel to the in-plane direction of the magnetic layer, the long side direction of the particles is further aligned with the vibration direction of electromagnetic waves incident orthogonally to the electromagnetic wave shielding material, the demagnetizing field can be reduced, and thus the magnetic layer can exhibit higher permeability. In this invention and this specification, "flat-shaped particles" refers to particles with an aspect ratio of 0.200 or less. The aspect ratio of the flat-shaped particles is preferably 0.150 or less, more preferably 0.100 or less. The aspect ratio of the flat-shaped particles can, for example, be 0.010 or more, 0.020 or more, or 0.030 or more. For example, the shape of the particles can be flattened by using a known method. Regarding flattening, for example, reference can be made to the description in Japanese Patent Application Publication No. 2018-131640, for example, to paragraphs 0016 and 0017 of that publication and the description of the embodiments. As a magnetic layer exhibiting high permeability, examples include magnetic layers containing flat-shaped particles of iron-silicon-aluminum alloy.

[0082] As described above, from the viewpoint of forming a magnetic layer exhibiting high magnetic permeability, it is preferable to arrange the long side direction of the flat-shaped particles to be more parallel to the in-plane direction of the magnetic layer. From this viewpoint, the sum of the absolute value of the average value of the orientation angles of the flat-shaped particles relative to the surface of the magnetic layer and the variance of the orientation angles, i.e., the degree of orientation, is preferably 30° or less, more preferably 25° or less, further preferably 20° or less, and even more preferably 15° or less. The degree of orientation can be, for example, 3° or more, 5° or more, or 10° or more, or even lower than the values ​​exemplified here. The method for controlling the degree of orientation will be described later.

[0083] In this invention and this specification, the aspect ratio and orientation degree of the magnetic particles are determined by the following method.

[0084] The cross-section of the magnetic layer was exposed using a known method. SEM images were then acquired from randomly selected areas of this cross-section. The imaging conditions were set to an accelerating voltage of 2 kV and a magnification of 1000x, and SEM images were acquired using backscattered electron imaging.

[0085] Using the `cv2.imread()` function of the OpenCV4 image processing library (manufactured by Intel Corporation), the second argument is set to 0 and read in grayscale. The midpoint between the high-brightness and low-brightness regions is used as the boundary, and the `cv2.threshold()` function is used to obtain a binarized image. The white parts (high-brightness parts) in the binarized image are identified as magnetic particles.

[0086] For the obtained binarized image, the externally circumscribed rectangle corresponding to each magnetic particle portion is obtained using the cv2.minAreaRect() function. This rectangle is then used as the return value of the cv2.minAreaRect() function to calculate the length of the long side, the length of the short side, and the rotation angle. When calculating the total number of magnetic particles contained in the binarized image, particles whose only portion is contained in the binarized image are also included. For particles whose only portion is contained in the binarized image, the length of the long side, the length of the short side, and the rotation angle are calculated for the portion contained in the binarized image. The ratio of the short side length to the long side length (short side length / long side length) is used as the aspect ratio of each magnetic particle. In this invention and specification, when the aspect ratio is 0.200 or less and the number of magnetic particles that are determined to be flat-shaped particles is 10% or more relative to the total number of magnetic particles contained in the binarized image, the magnetic layer is determined to be a "magnetic layer containing flat-shaped particles as magnetic particles". Furthermore, the "orientation angle" is determined based on the rotation angle obtained above, as the rotation angle relative to the horizontal plane (the surface of the magnetic layer).

[0087] Particles with an aspect ratio of 0.200 or less obtained from the binarized image are identified as flat-shaped particles. The absolute value of the mean (arithmetic mean) and the sum of the variances of the orientation angles of all flat-shaped particles contained in the binarized image are calculated. This sum is used as the "orientation degree". Furthermore, the coordinates of the circumscribed rectangle are calculated using the `cv2.boxPoints()` function, and an image obtained by rotating the circumscribed rectangle to coincide with the original image is created using the `cv2.drawContours()` function, excluding obviously falsely detected rotated circumscribed rectangles from the aspect ratio and orientation degree calculations. The average (arithmetic mean) of the aspect ratios of the particles identified as flat-shaped particles is used as the aspect ratio of the flat-shaped particles contained in the magnetic layer of the measured object. This aspect ratio can be 0.200 or less, preferably 0.150 or less, and more preferably 0.100 or less. The aforementioned aspect ratio can, for example, be 0.010 or more, 0.020 or more, or 0.030 or more.

[0088] The content of magnetic particles in the aforementioned magnetic layer relative to the total mass of the magnetic layer can be, for example, 50% or more by mass, 60% or more by mass, 70% or more by mass, or 80% or more by mass, and can be, for example, less than 100% by mass, less than 98% by mass, or less than 95% by mass.

[0089] As a magnetic layer, in one approach, a sintered body (ferrite plate) of ferrite particles can be used. Considering that electromagnetic wave shielding materials sometimes need to be cut to a desired size or bent into a desired shape, a resin-containing layer is preferred as the magnetic layer compared to a ferrite plate as a sintered body.

[0090] In one embodiment, the magnetic layer sandwiched between the two metal layers can be an insulating layer. In this invention and specification, "insulating" means a conductivity of less than 1 S (Siemens) / m. The conductivity of a particular layer is calculated using the following formula, based on the surface resistivity and thickness of the layer. Conductivity can be measured using known methods.

[0091] Conductivity [S / m] = 1 / (Surface resistivity [Q] × Thickness [m])

[0092] The inventors propose that, from the viewpoint of achieving higher electromagnetic wave shielding performance in the aforementioned electromagnetic wave shielding material, the magnetic layer is preferably an insulating layer. From this viewpoint, the conductivity of the magnetic layer is preferably less than 1 S / m, more preferably 0.5 S / m or less, even more preferably 0.1 S / m or less, and even more preferably 0.05 S / m or less. For example, the conductivity of the magnetic layer can be 1.0 × 10⁻⁶. -12 S / m or higher or 1.0×10 -10 S / m or higher.

[0093] (resin)

[0094] The magnetic layer can be a layer containing resin, or a layer containing magnetic material (e.g., magnetic particles) and resin. In this invention and specification, "resin" refers to a polymer, and also includes rubber and elastomers. Polymers include homopolymers and copolymers. Rubber includes natural rubber and synthetic rubber. Furthermore, an elastomer is a polymer exhibiting elastic deformation. In this invention and specification, a layer containing both magnetic material and resin corresponds to a "magnetic layer." In a magnetic layer containing magnetic material and resin, the resin content, based on 100 parts by mass of magnetic material, can be, for example, 1 part by mass or more, 3 parts by mass or more, or 5 parts by mass or more, and can be 20 parts by mass or less, or 15 parts by mass or less.

[0095] Resin acts as an adhesive in the magnetic layer. Examples of resins used in the magnetic layer include conventionally known thermoplastic resins, thermosetting resins, UV-curing resins, radiation-curing 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, ABS (acrylonitrile-butadiene-styrene) resins, nitrile-butadiene rubbers, styrene-butadiene rubbers, epoxy resins, phenolic resins, amide resins, silicone resins, styrene-based elastomers, olefin-based elastomers, vinyl chloride-based elastomers, polyester elastomers, polyamide elastomers, polyurethane elastomers, and acrylic elastomers.

[0096] In addition to the above-mentioned components, the magnetic layer may contain one or more known additives such as curing agents, dispersants, stabilizers, and coupling agents in any amount.

[0097] When the aforementioned electromagnetic wave shielding material comprises only one magnetic layer, the thickness of this magnetic layer can be, for example, 5 μm or more. From the viewpoint of further improving the shielding performance of the electromagnetic wave shielding material, it is preferably 10 μm or more, and more preferably 20 μm or more. On the other hand, the thickness of this magnetic layer can be, for example, 100 μm or less or 90 μm or less. From the viewpoint of further improving processability, it is preferably less than 90 μm, more preferably 80 μm or less, and even more preferably 70 μm or less.

[0098] When the aforementioned electromagnetic wave shielding material comprises two or more magnetic layers, the thickness of each of these two or more magnetic layers (i.e., the thickness of each individual layer) can be, for example, 5 μm or more. From the viewpoint of further improving the shielding performance of the electromagnetic wave shielding material, it is preferably 10 μm or more, and more preferably 20 μm or more. On the other hand, the thickness of each magnetic layer can be, for example, 100 μm or less or 90 μm or less. From the viewpoint of further improving processability, it is preferably less than 90 μm, and more preferably 80 μm or less. The thickness of each of the two or more magnetic layers can be the same or different.

[0099] When the electromagnetic wave shielding material contains only one magnetic layer, this magnetic layer is a magnetic layer sandwiched between two metal layers.

[0100] When the aforementioned electromagnetic wave shielding material comprises two or more magnetic layers, at least one magnetic layer is a magnetic layer sandwiched between two metal layers, or the two or more magnetic layers are each a magnetic layer sandwiched between two metal layers. Specific examples of the layer structure of such electromagnetic wave shielding materials will be described later.

[0101] In any of the above cases, there may be one or more other layers between the magnetic layer and the metal layer. These other layers will be described later.

[0102] <Metallic Layer>

[0103] The aforementioned electromagnetic wave shielding material has a multilayer structure in which a magnetic layer is sandwiched between two metal layers. The electromagnetic wave shielding material may include one or more such multilayer structures. That is, the electromagnetic wave shielding material includes at least two metal layers, and may include three or more metal layers, and includes at least one magnetic layer, and may include two or more magnetic layers. In one embodiment, the two or more metal layers included in the electromagnetic wave shielding material have the same composition and thickness, while in another embodiment, their composition and / or thickness are different. This also applies to the case where the electromagnetic wave shielding material includes two or more magnetic layers, and also to the case where the electromagnetic wave shielding material includes two or more other layers such as the resin layer described later.

[0104] In this invention and specification, "metal layer" refers to a layer containing metal. The metal layer may be a layer containing one or more metals in the form of a pure metal composed 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 non-metal elements.

[0105] The metal layer included in the aforementioned electromagnetic wave shielding material can 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 shielding material. This is preferred from the viewpoint of improving the shielding performance of the electromagnetic wave shielding material. A higher propagation constant results in a greater attenuation effect, and higher conductivity results in a higher propagation constant; therefore, the metal layer preferably contains a metal element with high conductivity. From this viewpoint, the metal layer preferably contains pure metals such as Ag, Cu, Au, or Al, or an alloy containing any of these as a main component. A pure metal is a metal composed of a single metallic element and may contain trace amounts of impurities. Generally, a metal composed of a single metallic element with a purity of 99.0% or higher is called a pure metal. Purity is based on mass. Regarding alloys, one or more metallic or non-metallic elements are usually added to pure metals to adjust the composition to prevent corrosion, improve strength, etc. The main component in the alloy is the component with the highest proportion based on mass, for example, a component accounting for 80.0% or more (e.g., less than 99.8% by mass) in the alloy. From an economic point of view, pure metals of Cu or Al or alloys containing Cu or Al as the main component are preferred. From the point of view, pure metals of Cu or alloys containing Cu as the main component are more preferred.

[0106] In one method, the purity of the metal in the metal layer, i.e., the metal content in the metal layer relative to the total mass of the metal layer, can be 99.0% by mass or more, 99.5% by mass or more, or 99.8% by mass or more. Unless otherwise specified, the metal content in the metal layer refers to the content based on mass. For example, pure metals or alloys processed into sheets can be used as the metal layer. For example, commercially available metal foils or metal foils produced by known methods can be used as the metal layer. Regarding pure Cu, sheets of various thicknesses (so-called copper foils) are commercially available. For example, such copper foils can be used as the metal layer. Regarding copper foils, in terms of their manufacturing methods, there are electrolytic copper foils obtained by electroplating copper foil onto a cathode, and rolled copper foils obtained by applying heat and pressure to an ingot to roll it into a very thin sheet. Any copper foil can be used as the metal layer of the aforementioned electromagnetic wave shielding material. Furthermore, for example, sheets of Al of various thicknesses (so-called aluminum foils) are also commercially available. For example, this aluminum foil can be used as a metal layer.

[0107] From the viewpoint of lightweighting electromagnetic wave shielding materials, one or both (preferably both) of the two metal layers sandwiching the magnetic layer are preferably metal layers containing metals selected from the group consisting of Al and Mg, and more preferably layers containing metals selected from the group consisting of Al and Mg as the main component. The main component of the metal layer refers to the component with the highest proportion based on mass. In the layer containing metals selected from the group consisting of Al and Mg as the main component, Al or Mg is the component with the highest proportion based on mass. The layer may contain only Al or Mg, or it may contain both Al and Mg. For Al and Mg, the value obtained by dividing the specific gravity by the conductivity (specific gravity / conductivity) is small. The smaller the value of the metal used, the lighter the electromagnetic wave shielding material that can achieve high shielding performance can be. As values ​​calculated based on literature values, for example, the values ​​obtained by dividing the specific gravity of Cu, Al, and Mg by the conductivity (specific gravity / conductivity) are as follows: Cu: 1.5 × 10 -7 m / s, Al: 7.6 × 10 -8 m / S, Mg: 7.6 × 10 -8 m / s. Based on the above values, Al and Mg can be considered preferred metals from the viewpoint of lightweighting electromagnetic wave shielding materials. Regarding metal layers containing metals selected from the group consisting of Al and Mg, in one embodiment, only one of Al and Mg may be contained, while in another embodiment, both may be contained. From the viewpoint of lightweighting electromagnetic wave shielding materials, one or both (preferably both) of the two metal layers sandwiching the magnetic layer are more preferably metal layers containing metals selected from the group consisting of Al and Mg at a content of 80.0% by mass or more, and even more preferably metal layers containing metals selected from the group consisting of Al and Mg at a content of 90.0% by mass or more. Metal layers containing at least Al in Al and Mg can be metal layers with an Al content of 80.0% by mass or more, or metal layers with an Al content of 90.0% by mass or more. Metal layers containing at least Mg in Al and Mg can be metal layers with a Mg content of 80.0% by mass or more, or metal layers with a Mg content of 90.0% by mass or more. The content of the metal selected from the group including Al and Mg, the Al content, and the Mg content can each be, for example, 99.9% by mass or less. The content of the metal selected from the group including Al and Mg, the Al content, and the Mg content are the contents relative to the total mass of the metal layer.

[0108] From the perspectives of economy, high conductivity, and lightweight electromagnetic wave shielding materials, one or both (preferably both) of the two metal layers sandwiching the magnetic layer are preferably metal layers containing metals selected from the group consisting of Al, Mg, and Cu, and more preferably layers containing metals selected from the group consisting of Al, Mg, and Cu as the main component. In layers containing metals selected from the group consisting of Al, Mg, and Cu as the main component, Al, Mg, or Cu is the component with the highest proportion by mass. This layer may contain only one of Al, Mg, and Cu, or two or three metals. From the above-mentioned perspectives, one or both (preferably both) of the two metal layers sandwiching the magnetic layer are more preferably metal layers containing metals selected from the group consisting of Al, Mg, and Cu at a content of 80.0% by mass or more, and even more preferably metal layers containing metals selected from the group consisting of Al, Mg, and Cu at a content of 90.0% by mass or more. The metal layer containing at least Al among Al, Mg, and Cu can be a metal layer with an Al content of 80.0% by mass or more, or an Al content of 90.0% by mass or more. The metal layer containing at least Mg among Al, Mg, and Cu can be a metal layer with a Mg content of 80.0% by mass or more, or a Mg content of 90.0% by mass or more. The metal layer containing at least Cu among Al, Mg, and Cu can be a metal layer with 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 metals selected from the group including Al, Mg, and Cu, the Al content, the Mg content, and the Cu content can each be, for example, 99.9% by mass or less. The content of the metals selected from the group including Al, Mg, and Cu, the Al content, the Mg content, and the Cu content are all content percentages relative to the total mass of the metal layer.

[0109] Regarding the thickness of the metal layers, from the viewpoint of further improving the processability of the metal layers and the shielding performance of the electromagnetic wave shielding material, the thickness of each layer is preferably 4 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more. On the other hand, regarding the processability of the metal layers, the thickness of each layer is preferably 200 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less. In the above-described electromagnetic wave shielding material, the thicknesses of the multiple metal layers can be the same or different.

[0110] <Resin-containing layer>

[0111] Regarding the aforementioned electromagnetic wave shielding material, in a multilayer structure with a magnetic layer sandwiched between two metal layers, one or more resin-containing layers may be present between one or both of the two metal layers and the magnetic layer. The resin-containing layer contains one or more types of resin. The specific manner in which the resin-containing layer is present will be explained below.

[0112] (Adhesive layer)

[0113] One type of resin-containing layer is the adhesive layer. In this invention and specification, "adhesive layer" refers to a layer that has a tacky surface at room temperature. Regarding tacky surface, "room temperature" refers to 23°C. When this layer comes into contact with an adhesive, it bonds to the adhesive through its adhesive force. Tacky surface generally refers to the property of exerting adhesive force for a short time after contact with an adhesive with very light force. In this invention and specification, the aforementioned "tacky surface" refers to a result of No. 1 to No. 32 in the inclined rolling ball initial tack test (test environment: temperature 23°C, relative humidity 50%) specified in JIS Z 0237:2009. When other layers are laminated on the surface of the adhesive layer, for example, the adhesive layer surface exposed by peeling off other layers can be subjected to the above test. When other layers are laminated on one surface and another surface of the adhesive layer respectively, the other layers on either surface side can be peeled off.

[0114] As an adhesive layer, an adhesive layer can be formed by coating and processing an adhesive layer forming composition containing adhesives such as acrylic adhesives, rubber adhesives, silicone adhesives, and urethane adhesives into a film.

[0115] The adhesive layer forming composition can be applied to a support, for example. Coating can be performed using known coating equipment such as a doctor blade coater or a die coater. Coating can be performed in a so-called roll-to-roll manner or in batches.

[0116] Examples of supports for the coating adhesive layer forming composition include films of various resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polymethyl methacrylate (PMMA), acrylic resins, cyclic polyolefins, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, and polyimide. Supports that have undergone a peeling treatment on the surface (coated surface) of the coating adhesive layer forming composition using known methods can be used. One method of peeling treatment is forming a release layer. Furthermore, commercially available resin films that have undergone peeling treatment can also be used as supports. By using a support whose coated surface has undergone peeling treatment, the adhesive layer can be easily separated from the support after film formation.

[0117] An adhesive layer can be formed by dissolving and / or dispersing the adhesive in a solvent, applying the adhesive layer formation composition to the coated surface, and then drying it. Alternatively, an adhesive tape containing an adhesive layer can also be used. For example, double-sided tape can be used as the adhesive tape. Double-sided tape has adhesive layers on both sides of the support. Furthermore, adhesive tapes with an adhesive layer on only one side of the support can also be used. Examples of supports include, for example, films, nonwoven fabrics, and paper made of various resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polymethyl methacrylate (PMMA), acrylics, cyclic polyolefins, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, and polyimide. As adhesive tapes with adhesive layers on one or both sides of the support, commercially available products can be used, as well as adhesive tapes made by known methods.

[0118] The thickness of the adhesive layer is not particularly limited, and the thickness of each layer can be, for example, more than 1 μm and less than 30 μm.

[0119] (Adhesive layer)

[0120] As one type of resin-containing layer, an adhesive layer can also be cited. In this invention and specification, an "adhesive layer" refers to a layer that, after contact between a liquid or gel-like adhesive and an adherend, solidifies through drying, curing, or other changes in state, and exerts its adhesiveness to the adherend through an anchoring effect, physical interaction, or the formation of chemical bonds. In one embodiment, the adhesive layer may be a layer that is not tacky at room temperature.

[0121] 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, and styrene-butadiene rubber. These resins can be liquid or gel-like. Alternatively, solid resins can be dissolved in a solvent to become liquid or gel-like. Examples of solvents contained in the adhesive include, for example, water, acetone, methyl ethyl ketone, cyclohexanone, and other ketone solvents; ethyl acetate, butyl acetate, cellosol acetate, propylene glycol monomethyl ether acetate, carbitol acetate, and other acetate solvents; cellosol, butyl carbitol, and other carbitols; toluene, xylene, and other aromatic hydrocarbon solvents; dimethylformamide, dimethylacetamide, N-methylpyrrolidone, and other amide solvents; ethanol, methanol, propanol, and other alcohol solvents; and dichloromethane, trichloroethylene, dichlorofluoroethane, and other halogen solvents.

[0122] The thickness of the adhesive layer is not particularly limited, and the thickness of each layer can be, for example, more than 1 μm and less than 30 μm.

[0123] (Resin layer)

[0124] As one way to include a resin layer, another example is a resin layer. In this invention and this specification, a "resin layer" is a resin film formed by molding a thermoplastic resin such as a synthetic resin into a film-like structure. The resin film has monomers capable of forming a film-like structure and is non-sticky at room temperature.

[0125] Examples of thermoplastic resins contained in resin films 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 elastomer (PP), styrene elastomer, ABS (acrylonitrile-butadiene-styrene) resin, polyethylene terephthalate (PET), polyethylene naphthalate (PEN) and other polyester resins, polycarbonate (PC) resin, polymethyl methacrylate (PMMA) and other acrylic resins, cyclic polyolefins, triacetyl cellulose (TAC) and various other resins.

[0126] The resin layer can be bonded to a metal layer or a magnetic layer via an adhesive layer or bonding layer. Furthermore, since the resin layer is a layer containing thermoplastic resin, it has the property of softening upon heating. It can flow and follow the minute irregularities on the surface of the adhesive when pressed while heated, exerting adhesive force through an anchoring effect, and then maintain its bonded state upon cooling. Therefore, in one embodiment, the resin layer can be bonded to other layers without using an adhesive layer or bonding layer.

[0127] Regarding the thickness of the resin layer, from the viewpoint of controlling the elongation at break of the electromagnetic wave shielding material to be 40% or more, the thickness of each resin layer is preferably 10 μm or more, more preferably 12 μm or more. On the other hand, regarding the thickness of the resin layer, from the viewpoint of controlling the product of the thickness of the electromagnetic wave shielding material and the tensile strength to be 40 N / mm or less, the thickness of each resin layer is preferably 250 μm or less, more preferably 230 μm or less, further preferably 210 μm or less, and even more preferably 190 μm or less. Regarding the above-mentioned electromagnetic wave shielding material, in a multilayer structure with a magnetic layer sandwiched between two metal layers, it is preferable to include one or more resin layers with the thickness within the above-mentioned range between one or both of the two metal layers and the magnetic layer. For example, the above-mentioned multilayer structure can include a magnetic layer with the thickness within the above-mentioned range between one of the two metal layers and the magnetic layer and / or between the other metal layer and the magnetic layer.

[0128] <Specific examples of layered structures>

[0129] The total number of magnetic layers contained in the aforementioned electromagnetic wave shielding material can be, for example, 1 to 4 layers. Furthermore, the electromagnetic wave shielding material can contain one or more magnetic layers sandwiched between two metal layers, or it can contain two or more such magnetic layers. It can also contain four or fewer such magnetic layers.

[0130] When the electromagnetic wave shielding material contains only one magnetic layer, this magnetic layer is a magnetic layer sandwiched between two metal layers.

[0131] When the aforementioned electromagnetic wave shielding material comprises two or more magnetic layers, at least one of these magnetic layers is a magnetic layer sandwiched between two metal layers. More specifically, all or only a portion of the magnetic layers included in the aforementioned electromagnetic wave shielding material are magnetic layers sandwiched between two metal layers.

[0132] In the multilayer structure of the aforementioned electromagnetic wave shielding material, in which a magnetic layer is sandwiched between two metal layers, one or more resin-containing layers may be included between one or both of the two metal layers and the magnetic layer. Preferably, at least one resin layer is used as the resin-containing layer located between the metal layer and the magnetic layer. In one embodiment, the aforementioned electromagnetic wave shielding material may include one or more polyester resin-containing layers between one or both of the two metal layers and the magnetic layer, and this polyester resin-containing layer is preferably a resin layer.

[0133] The aforementioned 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 another embodiment, the resin layer and the magnetic layer may be directly connected in the aforementioned multilayer structure. That is, the resin layer and the magnetic layer may be adjacent without passing through other layers. Furthermore, in the aforementioned multilayer structure, at least one of the two metal layers may be directly connected to the magnetic layer. That is, at least one of the two metal layers and the magnetic layer may be adjacent without passing through other layers.

[0134] The aforementioned electromagnetic wave shielding material may, for example, comprise 1 to 12 resin-containing layers. The total number of resin layers (preferably resin layers having the thickness described above) in the aforementioned electromagnetic wave shielding material may, for example, be 1 to 4 layers. The total number of layers selected from the group consisting of adhesive layers and bonding layers in the aforementioned electromagnetic wave shielding material may, for example, be 1 to 4 layers or 1 to 8 layers.

[0135] One or both outermost layers of the aforementioned electromagnetic wave shielding material are metal layers. This helps the electromagnetic wave shielding material to exhibit high shielding performance against magnetic field waves in the low-frequency region of 100kHz to 1MHz. Furthermore, having at least one outermost layer of the aforementioned electromagnetic wave shielding material as a metal layer also helps to suppress edge peeling in the molded product obtained through molding processing. In one embodiment, one or both outermost layers of the aforementioned electromagnetic wave shielding material may be metal layers sandwiched together with other metal layers containing a magnetic layer.

[0136] Examples of the configuration of the "magnetic layer," "metal layer," "resin layer," and "adhesive layer" in the aforementioned electromagnetic wave shielding material are given below. Hereinafter, the symbol " / " indicates that the layer described on the left side of the symbol is directly connected to the layer described on the right side without passing through other layers. In Examples 1 to 3 below, the "adhesive layer" may include a support, and the "adhesive layer" may also be an adhesive tape with an adhesive layer on one or both sides of the support. For example, as shown in Example 3, the metal layer sandwiching a certain magnetic layer may also be a metal layer sandwiching other magnetic layers. For example, in Example 3, metal layer 2 is one of the two metal layers sandwiching magnetic layer 1, and also one of the two metal layers sandwiching magnetic layer 2. Furthermore, in Example 3, one outermost layer of the electromagnetic wave shielding material is metal layer 1 sandwiching magnetic layer 1 together with metal layer 2, and the other outermost layer of the electromagnetic wave shielding material is metal layer 3 sandwiching magnetic layer 2 together with metal layer 2.

[0137] Example 1: "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"

[0138] Example 2: "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"

[0139] Example 3: "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"

[0140] Example 4: "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"

[0141] Example 5: "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"

[0142] Example 6: "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"

[0143] Example 7: "Metal layer 1 / Adhesive layer 1 or Adhesive layer 1 / Resin layer 1 / Magnetic layer 1 / Metal layer 2 / Magnetic layer 2 / Metal layer 3 / Adhesive layer 2 or Adhesive layer 2 / Resin layer 2"

[0144] <Manufacturing Methods of Electromagnetic Wave Shielding Materials>

[0145] (Methods for forming magnetic layers)

[0146] Regarding the aforementioned magnetic layer, it can be produced, for example, by drying a coating layer formed by applying the magnetic layer forming composition. The magnetic layer forming composition can contain the components described above, and can contain one or more solvents in any way. Various organic solvents can be listed as solvents, such as ketone solvents like acetone, methyl ethyl ketone, and cyclohexanone; acetate solvents like ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; carbitol solvents like butyl carbitol; aromatic hydrocarbon solvents like toluene and xylene; and amide solvents like dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. One or more solvents, selected considering the solubility of the components used in the preparation of the magnetic layer forming composition, can be mixed in any proportion. The solvent content of the magnetic layer forming composition is not particularly limited and can be determined considering the coatability of the magnetic layer forming composition.

[0147] The composition for forming a magnetic layer can be prepared by mixing various components sequentially or simultaneously in any order. Furthermore, dispersion can be performed using known dispersers such as ball mills, bead mills, sand mills, and roller mills, and / or mixing can be performed using known mixers such as vibratory mixers, as needed.

[0148] The composition for forming the magnetic layer can be coated onto a support, for example. Coating can be performed using known coating equipment such as a doctor blade coater or a die coater. Coating can also be performed in a so-called roll-to-roll manner or in batches.

[0149] Examples of supports for the composition for forming a magnetic coating include films of various resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polymethyl methacrylate (PMMA), acrylic resins, cyclic polyolefins, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, and polyimide. For details regarding these resin films, please refer to paragraphs 0081 to 0086 of Japanese Patent Application Publication No. 2015-187260. As a support, a support whose surface (coated surface) of the composition for forming a magnetic coating has undergone a peeling treatment by a known method can be used. One method of peeling treatment is forming a release layer. For details regarding release layers, please refer to paragraph 0084 of Japanese Patent Application Publication No. 2015-187260. Furthermore, commercially available resin films that have undergone peeling treatment can also be used as supports. By using a support whose coated surface has undergone a peeling process, the magnetic layer can be easily separated from the support after film formation.

[0150] The coating layer formed by the magnetic layer forming composition can be dried using known methods such as heating or blowing warm air. The drying process can be carried out, for example, under conditions that allow the solvent contained in the magnetic layer forming composition to evaporate. As an example, the drying process can be carried out for 1 minute to 2 hours in a heated atmosphere at a temperature of 80–150°C.

[0151] The orientation degree of the flattened particles described above can be controlled by the type of solvent, amount of solvent, liquid viscosity, coating thickness, etc., in the composition for forming the magnetic layer. For example, if the solvent has a low boiling point, the orientation degree tends to increase due to convection generated during drying. If the amount of solvent is small, the orientation degree tends to increase due to physical interference between adjacent flattened particles. On the other hand, if the liquid viscosity is low, the flattened particles are more likely to rotate, thus the orientation degree tends to decrease. If the coating thickness is thin, the orientation degree tends to decrease. Furthermore, performing the pressure treatment described later helps to reduce the orientation degree. By adjusting the various manufacturing conditions described above, the orientation degree of the flattened particles can be controlled within the range described above.

[0152] (Pressure treatment of the magnetic layer)

[0153] Regarding the magnetic layer, a pressure treatment can be performed after film formation. By applying pressure to a magnetic layer containing magnetic particles, the density of magnetic particles within the magnetic layer can be increased, resulting in higher permeability. Furthermore, for magnetic layers containing flattened particles, the orientation value can be reduced through pressure treatment, leading to even higher permeability.

[0154] Regarding the pressurization process, pressure can be applied in the thickness direction of the magnetic layer using a flatbed press, roller press, or similar method. A flatbed press applies pressure by placing the object to be pressed between two flat, upper and lower pressure plates and pressing the plates together using mechanical or hydraulic pressure. A roller press applies pressure by passing the object between rotating pressure rollers arranged above and below and applying mechanical or hydraulic pressure to the rollers, or by ensuring the distance between the pressure rollers is less than the thickness of the object being pressed.

[0155] The pressure during pressurization can be set arbitrarily. For example, in the case of a flatbed press, it can be 1 to 50 N (Newtons) / mm. 2 In the case of a roller press, for example, the linear pressure is 20–400 N / mm.

[0156] The pressurization time can be set arbitrarily. When using a flatbed press, it can be set from 5 seconds to 30 minutes. When using a roller press, the pressurization time can be controlled by the conveying speed of the material being pressurized, for example, from 10 cm / min to 200 m / min.

[0157] The materials for the pressure plate and pressure roller can be selected from metal, ceramic, plastic, rubber, etc.

[0158] During the pressurization process, temperature can be applied to the upper and lower plates or one side of the platen press, or to one side of the upper and lower rollers of the roll press. Heating softens the magnetic layer, resulting in a high compression effect when pressure is applied. The heating temperature can be set arbitrarily, for example, between 50°C and 200°C. This heating temperature can be the internal temperature of the platen or roller. This temperature can be measured using a thermometer installed inside the platen or roller.

[0159] After heating and pressurizing the platen, the magnetic layer can be removed by separating the platen while it is still hot. Alternatively, the platen can be cooled by water cooling, air cooling, or other methods while maintaining pressure, and then the platen can be separated to remove the magnetic layer.

[0160] In a roller press, the magnetic layer can be cooled by water cooling, air cooling, or other methods immediately after the pressing is completed.

[0161] The pressurization process can be repeated more than twice.

[0162] When the magnetic layer is formed on the release film, pressure processing can be performed, for example, while it is laminated on the release film. Alternatively, the magnetic layer can be peeled off from the release film and pressure processing can be performed on a single layer.

[0163] (Adhesion of various layers)

[0164] Adhesive layers or bonding agents can be used for bonding various layers. Regarding adhesive layers and bonding agents, as described above.

[0165] Furthermore, in the aforementioned electromagnetic wave shielding material, adjacent layers can be bonded together by applying pressure and heat. A plate press, roller press, or similar device can be used for this bonding process. For example, when the magnetic layer is configured to be in direct contact with an adjacent layer, the magnetic layer softens during the bonding process, promoting contact with the surface of the adjacent layer. This allows the magnetic layer to be bonded to the adjacent layer without the need for other layers. The bonding pressure can be set arbitrarily. In the case of a plate press, for example, it is 1 to 50 N / mm. 2 In the case of a roller press, the linear pressure is, for example, 20–400 N / mm. The pressing time can be set arbitrarily. In the case of a plate press, it is, for example, 5 seconds to 30 minutes. In the case of a roller press, it can be controlled by the conveying speed of the material being pressed, for example, a conveying speed of 10 cm / min to 200 m / min. The pressing temperature can be selected arbitrarily, for example, above 20°C and below 200°C. The above-mentioned pressing temperature can be, for example, the internal temperature of the pressure plate or roller.

[0166] The aforementioned electromagnetic wave shielding material can be assembled into electronic components or electronic devices in any shape. The electromagnetic wave shielding material can be sheet-like, and its size is not particularly limited. In this invention and this specification, "sheet" and "film" have the same meaning. Furthermore, the aforementioned electromagnetic wave shielding material can also be a stereolithographic product formed by stereolithographically molding a sheet-like electromagnetic wave shielding material, or it can be a sheet-like electromagnetic wave shielding material used for stereolithography. Various molding methods such as compression molding, vacuum molding, and air molding can be used as stereolithography methods. Regarding molding methods, molding performed without heating the molding object and / or the mold, or heating under conditions where the temperature is not excessively increased, is generally referred to as cold forming. The aforementioned electromagnetic wave shielding material exhibits excellent formability for cold forming. Therefore, the aforementioned electromagnetic wave shielding material is suitable for cold forming such as drawing and stretching. Drawing is a molding method that uses a pair of dies (a female die and a male die) to stamp a sheet-like molding object into bottomed containers of various shapes such as cylinders, square tubes, and cones. In contrast, the method of forming a curved shape from a flat sheet object is called stretch forming. Stretch forming can also be performed using only a male die without a female die. Deep drawing is broadly divided into deep drawing and shallow drawing. Shallow drawing produces shallow-depth products, while deep drawing produces deep-depth products (e.g., deeper than the diameter of a cylinder or cone, or the length of one side of a pyramid). The electromagnetic wave shielding material described above can be an electromagnetic wave shielding material that is not prone to breakage in products formed by this stereolithography method. Furthermore, the electromagnetic wave shielding material described above can also be an electromagnetic wave shielding material that is not prone to edge peeling in products formed by this stereolithography method. Known techniques can be applied to stereolithography methods.

[0167] [Electronic Components]

[0168] One aspect of the present invention relates to an electronic component comprising the aforementioned electromagnetic wave shielding material. Examples of such electronic components include those found in electronic devices such as mobile phones, mobile information terminals, and medical devices, as well as various electronic components such as semiconductor elements, capacitors, coils, and cables. The electromagnetic wave shielding material can, for example, be three-dimensionally molded into any shape according to the shape of the electronic component and disposed inside the electronic component, or it can be three-dimensionally molded into the shape of a covering material covering the outside of the electronic component and disposed as a covering material. Alternatively, it can be three-dimensionally molded into a cylindrical shape and disposed as a covering material covering the outside of a cable.

[0169] [Electronic Devices]

[0170] One aspect of the present invention relates to an electronic device comprising the aforementioned electromagnetic wave shielding material. Examples of such electronic devices include mobile phones, mobile information terminals, medical devices, and other electronic devices; electronic devices comprising various electronic components such as semiconductor elements, capacitors, coils, and cables; and electronic devices formed by mounting electronic components on a circuit board. This electronic device can include the aforementioned electromagnetic wave shielding material as a component of the electronic components included in the device. Furthermore, the aforementioned electromagnetic wave shielding material, as a component of the electronic device, can be disposed inside the electronic device, or can be disposed as a covering material covering the outside of the electronic device. Alternatively, it can be three-dimensionally formed into a cylindrical shape and disposed as a covering material covering the outside of a cable.

[0171] As an example of the use of the aforementioned electromagnetic wave shielding material, the use of a semiconductor package on a printed circuit board covered with the shielding material can be cited. For example, "Electromagnetic Wave Shielding Technology in Semiconductor Packaging" (Toshiba review Vol. 67 No. 2 (2012) P. 8) discloses a method for achieving high shielding effect by electrically connecting the side vias at the end of the package substrate to the inner surface of the shielding material to perform grounding wiring when covering a semiconductor package with a shielding material. For this wiring, the outermost layer of the shielding material on the electronic component side is preferably a metal layer. Regarding the aforementioned electromagnetic wave shielding material, since one or both outermost layers of the shielding material are metal layers, it is preferable to use it when performing the wiring as described above.

[0172] Example

[0173] The present invention will now be described in more detail with reference to embodiments. However, the present invention is not limited to the implementation methods shown in the embodiments.

[0174] [Example 1]

[0175] <Preparation of Composition (Coating Solution) for Forming Magnetic Layers>

[0176] Add to plastic bottles

[0177] 100g of Fe-Si-Al flat magnetic particles (MFS-SUH manufactured by MKT Corporation)

[0178] 27.5g of polyurethane resin (UR-6100 manufactured by TOYOBO CO., Ltd.) with a solid content of 30% by mass.

[0179] Polyfunctional isocyanate (CORONATE L manufactured by TOSOH CORPORATION) 0.5g,

[0180] Cyclohexanone 233g,

[0181] The coating solution was prepared by mixing with a vibratory mixer for 1 hour.

[0182] <Creation of a Magnetic Layer>

[0183] The coating liquid was applied to the release surface of a PET (polyethylene terephthalate) film (PET75JOL manufactured by NIPPA Corporation, hereinafter referred to as "release film") that had undergone release treatment using a doctor blade coater with a coating gap of 300 μm. The film was then dried in a drying apparatus with an internal atmosphere temperature of 80°C for 30 minutes to obtain a film-like magnetic layer.

[0184] The upper and lower plates of the platen press (a large hot press TA-200-1W manufactured by YAMAMOTO ENG.WORKS Co., LTD.) are heated to 140°C (internal temperature of the plates). The magnetic layer on the release film, along with the release film itself, is placed in the center of the plates, and an application of 4.66 N / mm is performed. 2 The pressure was maintained for 10 minutes. While maintaining the pressure, the upper and lower pressure plates were cooled to 50°C (internal temperature of the pressure plates), and then the magnetic layer was removed together with the release film.

[0185] A portion of the magnetic layer after the release film is peeled off is cut as a sample sheet for evaluating the magnetic layer described below. A 15cm × 15cm magnetic layer is then cut from the magnetic layer after the sample sheet is taken, and used to fabricate the following electromagnetic wave shielding material.

[0186] <Fabrication of Electromagnetic Wave Shielding Materials>

[0187] Two 15cm x 15cm laminates were prepared by cutting PANAC's ALPET 50-50K (a laminate made by bonding a 50μm thick aluminum foil (a metal layer with an Al content of 99.0% or more by mass) and a 50μm thick polyester film (a resin layer) with a 3μm thick adhesive layer) into 15cm x 15cm sizes.

[0188] The magnetic layer, as described above, is overlapped onto the polyester film of one of the two laminates. Then, the other laminate is overlapped onto this magnetic layer with the polyester film and magnetic layer in contact. This results in a laminate containing a magnetic layer.

[0189] The upper and lower plates of a plate press (a large hot press TA-200-1W manufactured by YAMAMOTO ENG.WORKS Co., LTD.) are heated to 140°C (internal temperature of the plates). The aforementioned laminate containing the magnetic layer is placed in the center of the plates, and an application of 4.66 N / mm is performed. 2The heat-pressed laminate was performed under pressure for 10 minutes. While maintaining pressure, the upper and lower pressure plates were cooled to 50°C (internal temperature of the pressure plates), and the heat-pressed laminate was removed.

[0190] Electromagnetic wave shielding material with the layered structure shown in Table 2 was produced using the method described above.

[0191] [Evaluation Method]

[0192] <Determination of the magnetic permeability of the magnetic layer>

[0193] A rectangular sample measuring 28 mm × 10 mm was cut from the aforementioned magnetic layer. The permeability was measured using a permeability measuring device (KEYCOM Corporation per01), and the real part (μ') of the complex relative permeability at 100 kHz was determined as the permeability. The calculated permeability was 148.

[0194] <Determination of the conductivity of the magnetic layer>

[0195] A cylindrical main electrode with a diameter of 30 mm was connected to the negative electrode side of a digital super-insulation resistance meter (TR-811A manufactured by Takeda Riken Industry Co., Ltd.), and a ring electrode with an inner diameter of 40 mm and an outer diameter of 50 mm was connected to the positive electrode side. The main electrode and the ring electrode were placed on a sample sheet of the aforementioned magnetic layer cut into 60 mm × 60 mm dimensions. A voltage of 25 V was applied to both electrodes to measure the individual surface resistivity of the magnetic layer. The conductivity of the magnetic layer was calculated based on the surface resistivity and the following formula. The calculated conductivity was 1.1 × 10⁻⁶. -2 S / m. The thickness used is the thickness of the magnetic layer determined by the following method.

[0196] Conductivity [S / m] = 1 / (Surface resistivity [Q] × Thickness [m])

[0197] <Obtaining Cross-sectional Images of Shielding Materials>

[0198] The following method was used to perform cross-sectional processing to expose the cross-section of the shielding material of Example 1.

[0199] The shielding material, cut into 3mm x 3mm pieces, was embedded in resin, and the cross-section of the shielding material was cut using an ion milling device (IM4000PLUS manufactured by Hitachi High-Tech Corporation).

[0200] The exposed shielding material cross-section was observed using a scanning electron microscope (SU8220 manufactured by Hitachi High-Tech Corporation) at an accelerating voltage of 2 kV and a magnification of 100x, yielding backscattered electron images. From the obtained images, the thicknesses of the magnetic layer, each metal layer, each resin layer, and each adhesive layer were measured at five locations relative to the scale bar. The arithmetic mean of these measurements was taken as the thickness of the magnetic layer, the thickness of each metal layer (thickness of each individual metal layer), the thickness of each resin layer (thickness of each individual resin layer), and the thickness of each adhesive layer (thickness of each individual adhesive layer). The thicknesses are shown in Table 2.

[0201] <Acquisition of Magnetic Layer Profile Images>

[0202] Similarly, in the cross-section of the shielding material of Example 1 exposed by cross-sectioning, the magnetic layer portion was observed using a scanning electron microscope (SU8220 manufactured by Hitachi High-Tech Corporation) at an accelerating voltage of 2kV and a magnification of 1000x, and a backscattered electron image was obtained.

[0203] <Determination of aspect ratio of magnetic particles and orientation degree of flat-shaped particles>

[0204] Using the backscattered electron image obtained above, the aspect ratio of the magnetic particles was determined using the method described above, and flattened particles were identified based on the aspect ratio value. As described above, it was determined whether the magnetic layer contained flattened particles as magnetic particles, and it was determined that the magnetic layer contained flattened particles. Furthermore, for the magnetic particles identified as flattened particles, the orientation degree was determined using the method described above, and the result was 13°. The average aspect ratio (arithmetic mean) of all particles identified as flattened particles was calculated as the aspect ratio of the flattened particles contained in the magnetic layer. The calculated aspect ratio was 0.071.

[0205] [The product of the elongation at break, thickness, and tensile strength of the shielding material]

[0206] A 50mm long × 10mm wide sheet was cut from the electromagnetic wave shielding material of Example 1 for measurement. The thickness of the cut sheet was measured at five randomly selected locations using a dry measuring tape (E-ST-100) manufactured by Tokyo Seimitsu Co., Ltd., and the arithmetic mean of these measurements was taken as the thickness of the shielding material. A Tensilon universal testing machine (RTF-1310) manufactured by A&D Company, Limited was used as a tensile testing machine, and tensile tests were performed on the sheet using the method described above. The elongation at break and tensile strength were determined. The calculated values ​​of the shielding material thickness, elongation at break, tensile strength, and the product of thickness and tensile strength are shown in Table 2.

[0207] [Evaluation of shielding performance]

[0208] As described below, the shielding performance of the electromagnetic wave shielding material of Example 1 was determined using the KEC method. KEC is an abbreviation for the Kansai Electronics Industry Promotion Center.

[0209] The signal generator (SG-4222 manufactured by Iwasaki Communications Inc.) was connected to the input connector of the KEC magnetic field antenna (JSE-KEC manufactured by Techno Science Japan) using an N-type cable.

[0210] The output connector of the wideband amplifier 315 was connected to the input connector of the spectrum analyzer (RIGOL RSA-3015T) using an N-type cable.

[0211] A test sample (electromagnetic shielding material) was placed between the opposing antennas of the KEC method magnetic field antenna. The signal generator and spectrum analyzer were set to the settings in Table 1, and the peak voltage of the signal was measured by pressing the peak button on the spectrum analyzer. In Table 1, the scale "10dB / div" indicates that each scale division is 10dB. "div" is an abbreviation for "division". Furthermore, the peak voltage was measured similarly without a test sample, and the shielding performance was calculated using the following formula. "dB" is short for decibel, and "dBm" is short for decibel milliwatt.

[0212] Shielding performance [dB] = Peak voltage [dBm] without a test sample - Peak voltage [dBm] with a test sample set

[0213] The shielding performance at 100kHz and 1MHz are shown in Table 2. The shielding performance at 100kHz is preferably 25dB or higher. The shielding performance at 1MHz is preferably 45dB or higher, more preferably 55dB or higher.

[0214] [Table 1]

[0215]

[0216] [Evaluation of moldability]

[0217] Using a deep-drawing die with a quadrilateral shape of 50mm on each side and a depth of 20mm, a bottom corner radius of 10mm, and a side corner radius of 6mm, electromagnetic wave shielding material cut to a size of 75mm × 75mm was formed to a depth of 15mm (in Table 2, "forming depth") under a wrinkle-resistance force of 0.2N. The aforementioned "corner radius" refers to the radius of curvature. For the following embodiments and comparative examples, the depths of the molded articles obtained under the same deep-drawing conditions as in Example 1 are shown in the forming depth column of Table 2.

[0218] Furthermore, the molded products obtained through deep drawing were visually inspected to evaluate the presence or absence of surface fractures and edge delamination. In the evaluation of edge delamination, the end faces of the molded products were visually inspected, and cases where interlayer delamination or intralayer cracks were found in the electromagnetic wave shielding material were evaluated as "present," while cases where neither interlayer delamination nor intralayer cracks were found were evaluated as "absent."

[0219] The above evaluation was also performed on the electromagnetic wave shielding materials of the embodiments and comparative examples described below.

[0220] [Example 2]

[0221] <Forming of Aluminum Foil with Resin Layer>

[0222] A 50μm thick aluminum foil (compliant with JIS H4160:2006 standard, alloy number 1N30 category (1)O, Al content ≥ 99.3% by mass) was bonded to a 50μm thick PET film (TORAY INDUSTRIES, INC., Lumirror 50-T60) using a 5μm thick double-sided tape (NeoFix5S2 manufactured by NEION Film Coatings Co., Ltd.), forming an aluminum foil with a resin layer (a laminate in which the metal layer and resin layer are bonded together by a double-sided tape containing an adhesive layer). The aluminum foil with the resin layer was cut into 15cm × 15cm pieces, and two 15cm × 15cm laminates were prepared. The aforementioned double-sided tape (NeoFix5S2 manufactured by NEION Film Coatings Co., Ltd.) is a double-sided tape with adhesive layers (each adhesive layer thickness: 1.5μm) on both sides of a 2μm thick PET film.

[0223] <Fabrication of Electromagnetic Wave Shielding Materials>

[0224] Using the two laminates described above, an electromagnetic wave shielding material with the layer structure shown in Table 2 was fabricated by overlapping a PET film with a magnetic layer, or by the method described in Example 1.

[0225] [Example 3]

[0226] <Formation of Adhesive Layer>

[0227] (Preparation of the composition (coating liquid) for forming the adhesive layer)

[0228] Add to plastic bottles

[0229] 100g of 30% by weight polyurethane resin (UR-6100 manufactured by Toyobo Co., Ltd.)

[0230] 900g of methyl ethyl ketone

[0231] The coating solution was prepared by mixing with a vibratory mixer for 1 hour.

[0232] (Film formation of the adhesive layer)

[0233] The coating liquid was applied to a 50μm thick aluminum foil (in accordance with JISH4160:2006 standard, alloy number 1N30 category (1) O, Al content ≥ 99.3% by mass) using a doctor blade coater with a coating gap of 300μm. The 3μm thick adhesive layer was then dried in a drying device with an internal atmosphere temperature of 80°C for 30 minutes to form a film.

[0234] <Forming of Aluminum Foil with Resin Layer>

[0235] The upper and lower plates of a platen press (a large hot press TA-200-1W manufactured by YAMAMOTO ENG.WORKS Co., LTD.) are heated to 140°C (internal temperature of the plates). An aluminum foil with an adhesive layer is placed in the center of the platen with the adhesive layer facing upwards. A 25μm thick PET film (Lumirror 25-T60 manufactured by TORAYINDUSTRIES, INC.) is then applied on the adhesive layer. A pressure of 4.66 N / mm is applied. 2 The pressure was maintained for 10 minutes. After cooling the upper and lower pressure plates to 50°C (internal temperature of the pressure plates) while maintaining the pressure, the aluminum foil with the resin layer (a laminate of metal and resin layers bonded together by an adhesive layer) was removed.

[0236] The aluminum foil with the resin layer made in this way was cut into 15cm×15cm size, and two 15cm×15cm stacked bodies were prepared.

[0237] <Fabrication of Electromagnetic Wave Shielding Materials>

[0238] Using the two laminates described above, an electromagnetic wave shielding material with the layer structure shown in Table 2 was fabricated by overlapping a PET film with a magnetic layer, or by the method described in Example 1.

[0239] [Example 4]

[0240] The PET film was changed to a thickness of 12 μm (Lumirror 12-S10 manufactured by TORAY INDUSTRIES, INC.), and an electromagnetic wave shielding material having the layer structure shown in Table 2 was prepared by the method described in Example 3.

[0241] [Example 5]

[0242] The PET film was changed to a thickness of 188 μm (Lumirror 188-T60 manufactured by TORAY INDUSTRIES, INC.). Otherwise, an electromagnetic wave shielding material with the layer structure shown in Table 2 was prepared by the method described in Example 3.

[0243] [Example 6]

[0244] Two 15cm x 15cm laminates were cut from AlPET 50-50K manufactured by PANAC Corporation. One of them was arranged with an aluminum foil and a magnetic layer connected together. Otherwise, an electromagnetic wave shielding material with the layer structure shown in Table 2 was produced by the method described in Example 1.

[0245] [Comparative Example 1]

[0246] Two 15cm x 15cm laminates cut from Alpet 50-50K manufactured by PANAC were arranged with aluminum foil and magnetic layers connected respectively. In addition, an electromagnetic wave shielding material with the layer structure shown in Table 2 was produced by the method described in Example 1.

[0247] [Comparative Example 2]

[0248] The PET film was changed to a thickness of 9 μm (T4100 manufactured by TOYOBO CO., LTD.), and an electromagnetic wave shielding material having the layer structure shown in Table 2 was prepared by the method described in Example 3.

[0249] [Comparative Example 3]

[0250] The PET film was changed to a thickness of 255 μm (Lumirror 255-T60 manufactured by TORAY INDUSTRIES, INC.). Otherwise, an electromagnetic wave shielding material with the layer structure shown in Table 2 was prepared by the method described in Example 3.

[0251] [Comparative Example 4]

[0252] Two 15cm × 15cm pieces of aluminum foil were cut from a 50μm thick aluminum foil (in accordance with JIS H4160:2006 standard, alloy number 1N30 category (1) O, Al content ≥ 99.3% by mass).

[0253] A 15cm × 15cm magnetic layer, obtained by the method described in Example 1, is overlapped on one of the two aluminum foils, and another aluminum foil is overlapped on the magnetic layer to obtain a laminate.

[0254] The upper and lower plates of a platen press (a large hot press TA-200-1W manufactured by YAMAMOTO ENG.WORKS Co., LTD.) are heated to 140°C (internal temperature of the plates). The aforementioned laminate is placed in the center of the plates, and a pressure of 4.66 N / mm is applied. 2 The heat-pressed laminate was performed under pressure for 10 minutes. While maintaining pressure, the upper and lower pressure plates were cooled to 50°C (internal temperature of the pressure plates), and the heat-pressed laminate was removed.

[0255] Electromagnetic wave shielding material with the layered structure shown in Table 2 was thus produced.

[0256] [Comparative Example 5]

[0257] Two 15cm x 15cm laminates, cut from AlPET50-50K manufactured by PANAC, were bonded together with the polyester film side facing inwards using 5μm thick double-sided tape (NeoFix 5S2 manufactured by NEION Film Coatings Co., Ltd.).

[0258] Electromagnetic wave shielding material with the layered structure shown in Table 2 was thus produced.

[0259] [Comparative Example 6]

[0260] Two 15cm × 15cm pieces of aluminum foil were cut from a 50μm thick aluminum foil (in accordance with JIS H4160:2006 standard, alloy number 1N30 category (1) O, Al content ≥ 99.3% by mass).

[0261] The two aluminum foils were respectively attached to the two sides of the 15cm×15cm magnetic layer obtained by the method described in Example 1 using double-sided tape (NeoFix5S2 manufactured by NEION Film Coatings Co., Ltd.) with a thickness of 5μm.

[0262]

[0263] The results shown in Table 2 confirm that the electromagnetic wave shielding material of the embodiment can provide high shielding performance for magnetic field waves in the low-frequency region of 100kHz to 1MHz, and has excellent formability.

[0264] Industrial availability

[0265] One aspect of the present invention is useful in the technical field of various electronic components and various electronic devices.

Claims

1. An electromagnetic wave shielding material, wherein, At least one outermost layer of an electromagnetic wave shielding material is a metal layer. The elongation at break of the electromagnetic wave shielding material is over 40%. The product of the thickness and tensile strength of the electromagnetic wave shielding material is less than 40 N / mm, and It contains one or more magnetic layers sandwiched between two metal layers.

2. The electromagnetic wave shielding material according to claim 1, wherein, The two outermost layers of the electromagnetic wave shielding material are metal layers.

3. The electromagnetic wave shielding material according to claim 1, wherein, One or two outermost layers of the electromagnetic wave shielding material are metal layers sandwiched together with other metal layers and containing magnetic layers.

4. The electromagnetic wave shielding material according to claim 1, wherein, The magnetic layer sandwiched between the two metal layers has one or more resin-containing layers between it and one or both of the two metal layers.

5. The electromagnetic wave shielding material according to claim 4, wherein, The resin is a polyester resin.

6. The electromagnetic wave shielding material according to claim 1, wherein, The magnetic layer contains magnetic particles.

7. The electromagnetic wave shielding material according to claim 6, wherein, The magnetic layer also contains resin.

8. The electromagnetic wave shielding material according to claim 1, wherein, The thickness of the magnetic layer is greater than 5 μm and less than 100 μm.

9. The electromagnetic wave shielding material according to claim 1, wherein, One or both of the two metal layers sandwiching the magnetic layer are layers containing a metal selected from the group consisting of Al, Mg and Cu as the main component.

10. The electromagnetic wave shielding material according to claim 1, wherein, The breaking elongation of the electromagnetic wave shielding material is above 40% and below 100%.

11. The electromagnetic wave shielding material according to claim 1, wherein, The product of the thickness and tensile strength of the electromagnetic wave shielding material is greater than 5 N / mm and less than 40 N / mm.

12. The electromagnetic wave shielding material according to claim 1, wherein, One or two outermost layers of the electromagnetic wave shielding material are metal layers sandwiched together with other metal layers, containing a magnetic layer. The magnetic layer sandwiched between the two metal layers has one or more layers containing polyester resin between it and one or both of the two metal layers. The magnetic layer contains magnetic particles and resin. The thickness of the magnetic layer is greater than 5 μm and less than 100 μm. One or both of the two metal layers sandwiching the magnetic layer are layers containing a metal selected from the group consisting of Al, Mg, and Cu as the main component. The electromagnetic wave shielding material has an elongation at break of 40% or more and 100% or less, and The product of the thickness and tensile strength of the electromagnetic wave shielding material is greater than 5 N / mm and less than 40 N / mm.

13. An electronic component comprising the electromagnetic wave shielding material according to any one of claims 1 to 12.

14. An electronic device comprising the electromagnetic wave shielding material according to any one of claims 1 to 12.

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