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• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K9/00—Screening of apparatus or components against electric or magnetic fields
  • H05K9/0073—Shielding materials
  • H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
  • H05K9/0083—Electromagnetic shielding materials, e.g. EMI, RFI shielding comprising electro-conductive non-fibrous particles embedded in an electrically insulating supporting structure, e.g. powder, flakes, whiskers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
  • C08J7/04—Coating
  • C08J7/05—Forming flame retardant coatings or fire resistant coatings
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
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  • C08K3/02—Elements
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  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/10—Metal compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
  • C08K3/20—Oxides; Hydroxides
  • C08K3/22—Oxides; Hydroxides of metals
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  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/38—Boron-containing compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L101/00—Compositions of unspecified macromolecular compounds
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C45/00—Amorphous alloys
  • C22C45/02—Amorphous alloys with iron as the major constituent
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
  • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
  • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
  • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
  • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
  • H01F1/147—Alloys characterised by their composition
  • H01F1/153—Amorphous metallic alloys, e.g. glassy metals
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
  • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
  • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
  • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
  • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
  • H01F1/147—Alloys characterised by their composition
  • H01F1/153—Amorphous metallic alloys, e.g. glassy metals
  • H01F1/15308—Amorphous metallic alloys, e.g. glassy metals based on Fe/Ni
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
  • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
  • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
  • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
  • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
  • H01F1/20—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder
  • H01F1/28—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder dispersed or suspended in a bonding agent
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K9/00—Screening of apparatus or components against electric or magnetic fields
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
  • B22F1/08—Metallic powder characterised by particles having an amorphous microstructure

Definitions

• the present invention relates to a near-field noise suppression sheet used to suppress extra radiated radio waves (noise) in electronic devices and communication devices.
• a near-field noise suppression sheet (hereinafter, also referred to as a “noise suppression sheet”) capable of converting unnecessary radiated radio waves (noise) into heat and preventing unnecessary magnetic field coupling is used as equipment or the like.
• this noise suppression sheet has a thickness of 0.05 mm to 2 mm, it can be inserted in the vicinity of an electronic component or electronic circuit, and is easy to process and has a high degree of freedom in shape. Therefore, the noise suppression sheet can be adapted to the miniaturization and weight reduction of the electronic device and the communication device, and is widely used as a noise countermeasure component of the electronic device and the communication device.
• a typical noise suppression sheet comprises a soft magnetic alloy powder processed into a flat shape and an organic binder, and the noise suppression effect can be obtained by the magnetic loss of the soft magnetic alloy powder due to the magnetic resonance. Therefore, the noise suppression performance of the noise suppression sheet depends on the magnetic permeability of the soft magnetic alloy powder contained in the noise suppression sheet.
• the imaginary part magnetic permeability ⁇ ′ ′ is distributed over the frequency band of radio wave noise to be absorbed (hereinafter also referred to as “target band”).
• target band the distribution of the imaginary part magnetic permeability ⁇ ′ ′ with respect to frequency.
• the ⁇ ′ dispersion differs in ⁇ ′ ′ value and distribution depending on the material and shape of the soft magnetic alloy powder contained in the noise suppression sheet. Therefore, in order to enhance the effect of noise suppression, it is necessary to select a noise suppression sheet suitable for the target band.
• the target band is as low as the kHz to MHz band, and the transmission becomes higher as the frequency becomes higher.
• the magnetic permeability decreases.
• the ⁇ ′ ′ value substantially approaches 1, the noise suppression effect can not be exhibited.
• Patent Documents 1 and 2 have a flat soft shape of Sendust composition.
• a noise suppression sheet containing magnetic alloy powder and carbon powder has been proposed: In the low frequency band, the magnetic loss by the soft magnetic alloy powder is used, and in the high frequency band, the dielectric loss by the carbon powder is used.
• the target band is wide band.
• Patent Document 3 is characterized by mainly containing flat soft magnetic particles composed of an iron-based amorphous alloy and an organic binder, and having a complex relative magnetic permeability ⁇ ′ ′ of 7 or more at 10 GHz.
• electromagnetic interference suppressing body which is described here, as the soft magnetic particles, the composition formula:.
• Patent Documents 4 and 5 disclose soft magnetic alloys having a structure in which ⁇ -Fe crystals are precipitated in an amorphous state.
• Patent Document 4 discloses an amorphous structure in which ⁇ -Fe crystal grains having an average particle diameter of 5 to 30 nm are precipitated, which has a composition formula: Fe 100-a-b-c-d Si a B b C c Cu d (where, 1% ⁇ a ⁇ 3% , 9% ⁇ b ⁇ 14%, 1% ⁇ c ⁇ 4%, 0.3% ⁇ d ⁇ 1.5%, 80% ⁇ 100-a A soft magnetic alloy represented by -b-c-d ⁇ 86%) is described.
• Patent Document 5 has an amorphous structure in which ⁇ -Fe crystal grains having an average particle diameter of 5 to 30 nm are precipitated, and the compositional formula: Fe 100-a-b-c-d Si a P b C c Cu d (however, 0% ⁇ a ⁇ 3%, 9% ⁇ b ⁇ 13%, 4% ⁇ c ⁇ 6%, 0.3% ⁇ d ⁇ 1.5%, 80% ⁇ 100 ⁇ ab ⁇ A soft magnetic alloy represented by cd ⁇ 86%) is described. And as an example, it is described that these soft-magnetic alloys can be applied to magnetic parts, such as a noise suppression sheet
• JP 2012-186384 A JP, 2013-182931, A JP, 2015-46538, A JP, 2016-94651, A Unexamined-Japanese-Patent No. 2016-94652 gazette
• the magnetic permeability of the noise suppression sheet is influenced not only by the composition of the alloy powder but also by the degree of orientation and the filling rate of the flat alloy powder in the noise suppression sheet. That is, since the flat alloy powder has magnetic anisotropy in the in-plane direction, it is necessary to increase the degree of orientation of the alloy powder in the in-plane direction of the sheet to increase the magnetic permeability of the noise suppression sheet. .
• the permeability of the noise suppression sheet is also influenced by the filling rate of the alloy powder contained in the sheet, and in order to increase the permeability of the noise suppression sheet, it is necessary to increase the density of the noise suppression sheet.
• a flame retardant noise suppression sheet is required due to the nature of the target device using the noise suppression sheet, and it is general to add a flame retardant as a countermeasure.
• the flame retardant is added, the degree of orientation of the flat alloy powder is lowered, and as a result, the magnetic permeability of the noise suppression sheet is lowered, and the frequency characteristics are also affected.
• Patent Documents 4 and 5 aim to obtain a soft magnetic alloy excellent in soft magnetic properties by optimizing the component composition and structure of the soft magnetic alloy, but the degree of orientation of the alloy powder in the noise suppression sheet No mention is made of the density and flame retardancy of the noise suppression sheet. Therefore, even if the noise suppression sheet is produced using the soft magnetic alloys described in Patent Documents 4 and 5, in addition to the target band being the MHz to GHz band, a noise suppression sheet having not only flame resistance but also The current situation is that the
• the flame-retardant noise suppressing sheet for the near field is characterized in that the rising frequency of the ⁇ ′ ′ dispersion is in the band of 1 to 10 MHz and the ⁇ ′ ′ dispersion is distributed to the GHz band. Intended to provide.
• a noise suppressing sheet for a near field comprising: a base material made of an organic substance, a flat alloy powder supported in the base material, and a flame retardant dispersed in the base material,
• the alloy powder has, in atomic percent, a composition formula: Fe 100 -X 1 -Y 1 (Si, P, C) X 1 Cu Y 1 (where 16 ⁇ X 1 + Y 1 ⁇ 24, 14.5 ⁇ X 1 ⁇ 24, and 0 ⁇ Y 1 ⁇ Alloy powder represented by 1.5) and / or a composition formula: Fe 100 -X 2 -Y 2 (Si, B, C) X 2 Cu Y 2 (where 16 ⁇ X2 + Y 2 ⁇ 24, 14.5 ⁇ X 2 ⁇ 24, and 0 Alloy powder represented by ⁇ Y 2 ⁇ 1.5),
• the phase structure of the alloy powder is composed of only an amorphous phase or a mixture of an amorphous phase or a mixture of an amorphous phase or a
• the alloy powder may be 19 ⁇ X1 + Y1 ⁇ 21, 18 ⁇ X1 ⁇ 21, and 0 ⁇ Y1 ⁇ 1.0, and / or 19 ⁇ X2 + Y2 ⁇ 21, 18 ⁇ X2 ⁇ 21, and 0 ⁇ Y2 ⁇
• the frequency at which the ⁇ ′ ′ value is 1 or more is 1 MHz to 10 MHz, and the ⁇ ′ ′ value at 10 GHz is 2 or more.
• the near-field noise suppression sheet described in (2) is 1 MHz to 10 MHz.
• the flame retardant is one or more non-halogen flame retardants selected from among aluminum hydroxide, magnesium hydroxide, zinc borate, melamine cyanate, and red phosphorus.
• the near-field noise suppression sheet according to any one of (4) to (4).
• the Fe is substituted with one or more elements selected from Al, Co, Ni, Cr, Nb, Mo, Ta, and W.
• the noise suppressing sheet for near field according to any one of (1) to (5).
• the noise suppression sheet contains one or more oxides selected from silicon, titanium, aluminum and zirconium, and the particle size of the oxide is 100 nm or less.
• the near-field noise suppression sheet according to any one of (1) to (10).
• a near-field noise suppression sheet capable of coping with magnetic field noise in a broad band of MHz to GHz band and also having flame retardancy.
• a near-field noise suppression sheet includes a base made of an organic substance, a flat alloy powder supported in the base, and a flame retardant dispersed in the base.
• the flat alloy powder has, in atomic percent, a composition formula: Fe 100 -X 1 -Y 1 (Si a P b C c ) X 1 Cu Y 1 (where 16 ⁇ X1 + Y1 ⁇ 24, 14.5 ⁇ X1 ⁇ 24, and 0 An alloy powder represented by ⁇ Y1 ⁇ 1.5 and / or a composition formula: Fe 100 ⁇ X 2 ⁇ Y 2 (Si d B e C f ) X 2 Cu Y 2 (where 16 ⁇ X 2 + Y 2 ⁇ 24, 14.5 ⁇ X 2 ⁇ And an alloy powder represented by 0 ⁇ Y2 ⁇ 1.5).
• Fe 100 -X 1 -Y 1 (Si a P b C c ) X 1 Cu Y 1 is expressed as Fe 100 -X 1 -Y 1 (Si, P, C) X 1 Cu Y 1 and Fe 100 -X 2 -Y 2 Si d B e C f) X2 Cu Y2 of Fe 100-X2-Y2 (Si , denoted B, C) and X2 Cu Y2.
• the total amount of Fe 100 -X 1 -Y 1 (Si, P, C) X 1 Cu Y 1 and Fe 100-X 2-Y 2 (Si, B, C) X 2 Cu Y 2 is preferably 50 mass% or more.
• the ratio of each alloy powder in the case where both Fe 100 -X 1 -Y 1 (Si, P, C) X 1 Cu Y 1 and Fe 100-X 2-Y 2 (Si, B, C) X 2 Cu Y 2 are contained is not particularly limited. .
• the phase structure of the alloy powder having the above composition has a structure consisting only of an amorphous phase.
• those containing Cu are mixed with an amorphous phase and a crystalline phase mainly composed of ⁇ -Fe by performing annealing treatment described later to precipitate ⁇ -Fe crystals. It can also be a matter of course.
• ⁇ -Fe is the main component means that the volume ratio of ⁇ -Fe in the crystal phase is 50% or more, preferably 70% or more.
• X1, X2 and Y1, Y2 of the above composition have 19 ⁇ X1 + Y1 ⁇ 21, 18 ⁇ X1 ⁇ 21, and 0 ⁇ Y1 ⁇ 1.0, and / or 19 ⁇ X2 + Y2 ⁇ It is preferable to satisfy 21, 18 ⁇ X2 ⁇ 21, and 0 ⁇ Y2 ⁇ 1.0.
• 3 atomic% or less of Fe may be substituted with one or more elements selected from Al, Co, Ni, Cr, Nb, Mo, Ta, and W.
• the total addition amount of the elements to be substituted exceeds 3 atomic%, the saturation magnetization of the alloy powder is significantly reduced, whereby the magnetic permeability of the noise suppression sheet is reduced. Therefore, the upper limit value is 3 atomic%.
• a flat alloy powder, an organic matter, a flame retardant, and an organic solvent are mixed to prepare a slurry.
• the raw material powder As a raw material powder of alloy powder, it is preferable to use a powder having the above-mentioned composition, and to make the shape of the raw material powder spherical.
• the raw material powder can be obtained by a gas atomization method or a water atomization method which is a general powder synthesis method.
• the average particle diameter of raw material powder means the particle diameter (50% accumulated particle diameter: D50) in 50% of the integration value in the particle size distribution calculated
• Flat alloy powder is obtained by mechanical processing of such spherical raw material powder.
• the average value of the thickness of the flat alloy powder is 0.1 ⁇ m or more It is preferable to carry out flattening so as to be 1.5 ⁇ m or less.
• the average value of the aspect-ratio of alloy powder may be 10 or more and 100 or less.
• the average value of the aspect ratio is 10 or more, the influence of the demagnetizing field in the plane of the flat alloy powder can be ignored, and if 100 or less, the degree of orientation of the alloy powder in the in-plane direction of the sheet is This is because it is possible to obtain a noise suppression sheet which is increased during film formation and has a flat surface.
• known or arbitrary machining such as a ball mill, attritor, or stamp mill can be suitably used.
• the “average value of thickness” is obtained by observing the ion milling polished surface of the cross section in the thickness direction of the noise suppression sheet produced by the method described later with a scanning electron microscope (SEM) and viewing in the visual field.
• the mean value of the thickness of the flat alloy powder is meant for 10 powders, and the “average value of the aspect ratio” is also 10 in the field of view as observed by SEM.
• the value of the ratio of length / thickness of the flat alloy powder is averaged for the powder of
• the alloy powder is annealed in an inert atmosphere such as nitrogen or argon.
• an inert atmosphere such as nitrogen or argon.
• the annealing conditions may be, for example, a temperature of 200 to 500 ° C. and a time of 0.5 to 5 hours.
• an alloy powder having a desired coercive force can be obtained by appropriately selecting the annealing conditions and controlling the phase structure of the alloy powder.
• the coercive force of the alloy powder is preferably 0.5 A / cm or more and 8 A / cm or less.
• the ⁇ ′ ′ dispersion start frequency can be present in the MHz band, and if 8 A / cm or less, ⁇ ′ ′ of sufficient size to suppress noise It is because a value can be obtained.
• a self-oxidized film or an externally treated film on the surface of the flat alloy powder for the purpose of applying an insulation treatment.
• the means and material for film formation are not particularly limited as long as they can maintain insulation.
• the thickness of the film is suitably 20 to 100 nm, and if the film is formed more than necessary, the volume of the magnetic phase decreases, so it is not possible to obtain a sufficiently large ⁇ ′ ′ value.
• a heat treatment in the air or a heat treatment in a hydrocarbon-based organic solvent is a typical method, and as a method of forming an external treatment film, a vapor phase method such as dip coating or CVD.
• the order of the above-mentioned insulation treatment and annealing treatment is not particularly limited.
• the flat alloy powder may also be surface-treated with one or more coupling agents selected from silicon, titanium, aluminum and zirconium.
• the method of coupling treatment is not particularly limited, and a typical treatment method will be described here. That is, the flat alloy powder is charged into a solvent in which the above-mentioned coupling agent is dissolved, and after stirring, the alloy powder is recovered and dried at a temperature of 100 to 200 ° C., for example. Thereby, an oxide having a particle size of 100 nm or less is formed on the surface of the alloy powder.
• the degree of familiarity with an organic substance to be described later is improved, and a noise suppression sheet having a high packing density of the alloy powder can be obtained.
• a ⁇ ′ ′ value large enough for noise suppression can be obtained.
• particles of insulating oxide resulting from the coupling agent are formed on the surface of the flat alloy powder, it also contributes to the improvement of the insulation of the alloy powder.
• an organic substance which comprises a base material the thing which does not contain a halogen element is preferable. This is because, in the conventional noise suppression sheet, organic substances such as chlorinated polyethylene having high flame retardancy were used, but in recent years, a noise suppression sheet containing no halogen element is required by environmental regulations such as the RoHS directive. It is from.
• a halogen element for example, any resin material such as epoxy resin, phenol resin, cellulose resin, polyethylene resin, polyester resin, or any rubber material such as silicone rubber, acrylic rubber, nitrile rubber, butyl rubber Materials, and arbitrary fiber materials such as non-woven fabric, polyester fiber, acrylic fiber, etc.
• organic substance may be mentioned, and the selection of the organic substance may be appropriately selected according to the purpose.
• organic substances have functions such as imparting of cohesion and plasticity, and isolation of alloy powders.
• a plasticizer such as dioctyl phthalate can be added as needed to enhance the flexibility of the noise suppression sheet.
• the average particle diameter of the finally obtained noise suppression sheet is 10 ⁇ m or less, preferably 0.2 ⁇ m to 8 ⁇ m, and more preferably 0.2 ⁇ m to 6 ⁇ m. Since the flame retardant is present dispersed in the flat alloy powder, when the average particle size exceeds 10 ⁇ m, the degree of orientation of the alloy powder in the in-plane direction of the sheet is significantly reduced. Therefore, even if the flame retardancy can be enhanced, the desired noise suppression effect can not be obtained. In addition, if the average particle diameter of a flame retardant is 0.2 micrometer or more, high flame retardance can be maintained.
• the average particle diameter of the flame retardant refers to the average value of the major axes of the ten flame retardants in the field of view when the ion milling polished surface of the cross section in the thickness direction of the noise suppression sheet is observed by SEM. means.
• the type of the flame retardant is not particularly limited, but it is preferably a flame retardant containing no halogen element as in the organic substance, and specifically, aluminum hydroxide, magnesium hydroxide, zinc borate, melamine cyanate, and One or more flame retardants selected from red phosphorus may be mentioned.
• the mixing ratio of the flat alloy powder, the flame retardant, and the organic substance is 5 parts by mass to 30 parts by mass of the flame retardant and 8 parts by mass to 30 parts of the organic substance when the flat alloy powder is 100 parts by mass. It is preferable to set it as part or less. If the flame retardant is 5 parts by mass or more, it becomes V1 or more in the flame retardancy test of UL94 standard, and the flame retardancy required for the noise suppression sheet can be secured, and if 30 parts by mass or less, the noise suppression This is because it is possible to suppress the magnetic permeability of the noise suppression sheet from being significantly reduced because the volume ratio of the alloy powder to the entire sheet is not significantly reduced.
• the organic substance is 8 parts by mass or more, the plasticity of the noise suppression sheet can be maintained, and if it is 30 parts by mass or less, the flat alloy powder is easily oriented in the horizontal direction of the sheet at the time of sheet molding. If the organic matter is added at such a compounding ratio, the surface resistance of the noise suppression sheet is 10 5 ⁇ / s even without the above-mentioned insulation treatment.
• the insulation property of the alloy powder itself is improved, so that the amount of the organic substance added can be reduced as compared with the case where the insulation treatment is not performed. Since the volume of the alloy powder in the noise suppression sheet is improved, the permeability is increased and the flame retardancy is also improved.
• the organic solvent is not particularly limited, and toluene, butyl acetate, ethyl acetate and the like can be used.
• the organic solvent is not included in the noise suppression sheet because it is evaporated in the subsequent step.
• the slurry can be produced by a known ball mill method. That is, flat alloy powder, flame retardant, organic substance, and organic solvent adjusted to a predetermined compounding ratio are charged into a container together with a ball mill media for promoting mixing and stirring, and these are rotated by rotating the container. A homogeneously dispersed slurry can be made.
• the slurry in the present embodiment can also be produced using a ball mill method. However, in the ball mill method, a large external force is applied to the flat alloy powder by the ball mill media, and it becomes difficult to keep the coercivity of the flat alloy powder in the range of 0.5 A / cm to 8 A / cm.
• a planetary mixing and stirring device that does not use ball media for the preparation of the slurry.
• the flat alloy powder, the flame retardant, the organic substance, and the organic solvent can be homogeneously mixed without giving a large external force to the flat alloy powder.
• the planetary stirring system promotes degassing of the gas contained in the slurry, it is possible to produce a slurry effective for obtaining a noise suppression sheet having a high density of 2.5 g / cm 3 or more. it can.
• a slurry comprising a flat alloy powder, a flame retardant, an organic substance, and an organic solvent is formed into a sheet by a doctor blade method and dried to prepare a formed body.
• This molded body has a structure in which a flat alloy powder is supported on a base made of an organic substance, and a flame retardant is dispersed between the alloy powders, and furthermore, a flat alloy is produced by shear stress during molding.
• the powders are oriented horizontally to one another.
• a known or arbitrary method such as a calendar roll method can be used, but when producing a noise suppression sheet having a thickness of 0.1 mm or less It is preferable to use a coating method such as a doctor blade method.
• the sheet-like compact is pressed in a state of being heated to a temperature higher than the softening point of the organic substance (for example, about 60 to 150 ° C.) Apply.
• the thickness of the noise suppression sheet obtained can be about 0.05 mm to 0.1 mm, and the density of the noise suppression sheet can also be 2.5 g / cm 3 or more. If the density is less than 2.5 g / cm 3 , the number of voids increases, the degree of horizontal orientation of the flat alloy powder decreases, and the ratio of the alloy powder to the whole sheet decreases, so the desired noise The suppression effect can not be obtained.
• the density of the noise suppression sheet is preferably 2.7 g / cm 3 or more.
• it is effective to increase the ratio of the alloy powder to the entire sheet by increasing the proportion of the flat alloy powder as much as possible as well as eliminating the voids.
• a flame retardant noise suppression sheet characterized in that the rising frequency of the ⁇ ′ ′ dispersion is in the band of 1 MHz to 10 MHz and the ⁇ ′ ′ dispersion is distributed to the GHz band. it can. More specifically, in the noise suppression sheet, at the rise of the ⁇ ′ ′ dispersion, the frequency at which the ⁇ ′ ′ value is 1 or more is present in the band of 1 MHz to 10 MHz, and the ⁇ ′ ′ value at 10 GHz is 2 or more. ing.
• the flame retardant may be added in advance when flattening the alloy powder, not when producing a slurry.
• the flame retardant when the alloy powder is subjected to flattening processing, the flame retardant is also crushed and crushed, so the flame retardant contained in the noise suppression sheet even if the average particle size of the flame retardant when added is more than 10 ⁇ m. Can be adjusted to 10 ⁇ m or less.
• Table 1 shows the phase structure measured by powder X-ray diffractometry and the coercivity measured by the coercivity measuring device for each flat alloy powder after the annealing treatment.
• magnesium hydroxide 9 ⁇ m-red phosphorus 7 ⁇ m and the comparative examples 5 to 8 Magnesium hydroxide was 13 ⁇ m-red phosphorus 13 ⁇ m, magnesium hydroxide 8 ⁇ m-red phosphorus 7 ⁇ m for Inventive Example 11, and magnesium hydroxide 6 ⁇ m-red phosphorus 6 ⁇ m for Inventive Example 12.
• this slurry was processed into a sheet-like molded body on a polyethylene terephthalate film by a doctor blade method.
• Table 1 shows the frequency at which the ⁇ ′ ′ value becomes 1 or more and the magnitude of the ⁇ ′ ′ value at 10 GHz when the ⁇ ′ ′ dispersion starts to rise.
• the component composition of the present invention is satisfied, the average particle diameter of the flame retardant is 10 ⁇ m or less, and the density of the noise suppression sheet is 2.5 g / cm 3 or more.
• the frequency at which the value of ⁇ ′ ′ is 1 or more is in the range of 1 to 10 MHz, and the value of ⁇ ′ ′ at 10 GHz exceeds 2.
• the magnetic characteristics are Possibly good, the ⁇ ′ ′ value at 10 GHz was above 4.5.
• the ⁇ ′ ′ value at 10 GHz was less than 2.
• Comparative Example 1 the magnetic flux density of the flat alloy powder also decreased due to the low Fe concentration, and the ⁇ ′ ′ value at 10 GHz Is considered to be less than two. Further, in Comparative Example 2, the component composition of the present invention is not satisfied, and since the coercive force of the flat alloy powder exceeds 8 A / cm, the soft magnetic characteristics are degraded, and the ⁇ ′ ′ value at 10 GHz is It is considered that it was less than 2. Further, in Comparative Examples 3 and 4 in which Cu exceeds 1.5 atomic%, it was found by X-ray diffraction measurement that a FeP compound having large magnetic anisotropy was formed.
• the coercivity exceeded 8 A / cm
• the distribution width of ⁇ ′ ′ with respect to the frequency was narrow
• the ⁇ ′ ′ value at 10 GHz was also 0.0. If the ⁇ ′ ′ value at 10 GHz is 2 or more, it is possible to effectively suppress the noise generated in recent electronic devices that are reduced in size, size, size, and frequency, if the ⁇ ′s value at 10 GHz is 2 or more. It can be.
• the average particle diameter of the flame retardant was more than 10 ⁇ m, and from the observation with SEM, a part where the in-plane orientation of the alloy powder was disturbed was confirmed everywhere. Therefore, at the beginning of the rise of the ⁇ ′ ′ dispersion, the frequency at which the ⁇ ′ ′ value is 1 or more exceeded 10 MHz, and the ⁇ ′ ′ value at 10 GHz was also below 2.
• the density of the noise suppression sheet was less than 2.5 g / cm 3, and it was confirmed by SEM observation everywhere that the orientation in the sheet plane of the alloy powder was disturbed. Therefore, at the beginning of the rise of the ⁇ ′ ′ dispersion, the frequency at which the ⁇ ′ ′ value is 1 or more exceeded 10 MHz, and the ⁇ ′ ′ value at 10 GHz was also below 2.
• the average particle diameter of the flame retardant is 8 ⁇ m or less, and the density of the noise suppression sheet is 2.7 g / cm 3 or more.
• the above frequency is in the range of 1 to 10 MHz, and the ⁇ ′ ′ value at 10 GHz exceeds 5.
• the in-plane orientation of the flat powder sheet as the average particle diameter of the flame retardant decreases. Becomes better, so that the ⁇ ′ ′ value at 10 GHz also becomes larger.
• Table 2 shows the phase structure and the coercivity measured by the method described above.
• each flat alloy powder 100 parts by mass of each flat alloy powder, 20 parts by mass of acrylic rubber (softening point: about 70 ° C.), 50 parts by mass of toluene, and 5 parts by mass of melamine cyanurate as a flame retardant and 1 part by mass of red phosphorus
• the average particle diameter of the flame retardant at the time of adding is set to magnesium hydroxide 9 ⁇ m-red phosphorus 7 ⁇ m for Inventive Examples 13 to 22 and Comparative Examples 13 to 16 and 21 to 24, and Comparative Examples 17 to 20.
• Magnesium hydroxide was 13 ⁇ m-red phosphorus 13 ⁇ m, magnesium hydroxide 8 ⁇ m-red phosphorus 7 ⁇ m for invention example 23, magnesium hydroxide 6 ⁇ m-red phosphorus 6 ⁇ m for invention example 24.
• this slurry was processed into a sheet-like molded body on a polyethylene terephthalate film by a doctor blade method.
• the permeability characteristics, the average particle diameter of the flame retardant, the density of the noise suppression sheet, and the surface resistance were measured by the methods described above for each of the invention examples and the comparative examples. The measurement results are shown in Table 2.
• Comparative Example 13 the magnetic flux density of the flat alloy powder also decreased due to the low Fe concentration, and the ⁇ ′ ′ value at 10 GHz Is considered to be less than 2. Further, in Comparative Example 14, the component composition of the present invention is not satisfied, and since the coercive force of the flat alloy powder exceeds 8 A / cm, the soft magnetic characteristics are degraded, and the ⁇ ′ ′ value at 10 GHz is It is considered that it was less than 2. Further, in Comparative Examples 15 and 16 in which Cu exceeds 1.5 atomic%, it was found by X-ray diffraction measurement that a compound of FeB having large magnetic anisotropy was formed. As a result, the coercive force exceeded 8 A / cm, the distribution width of ⁇ ′ ′ with respect to frequency was narrow, and the ⁇ ′ ′ value at 10 GHz was also 0.0.
• the average particle diameter of the flame retardant was more than 10 ⁇ m, and from the observation with SEM, a portion in which the in-plane orientation of the alloy powder was disturbed was confirmed everywhere. Therefore, at the beginning of the rise of the ⁇ ′ ′ dispersion, the frequency at which the ⁇ ′ ′ value is 1 or more exceeded 10 MHz, and the ⁇ ′ ′ value at 10 GHz was also below 2.
• the density of the noise suppression sheet was less than 2.5 g / cm 3 , and SEM observation confirmed everywhere that the orientation in the sheet surface of the alloy powder was disturbed. Therefore, at the beginning of the rise of the ⁇ ′ ′ dispersion, the frequency at which the ⁇ ′ ′ value is 1 or more exceeded 10 MHz, and the ⁇ ′ ′ value at 10 GHz was also below 2.
• the ⁇ ′ ′ value starts to rise, and the ⁇ ′ ′ value is 1
• the above frequency is in the range of 1 to 10 MHz, and the ⁇ ′ ′ value at 10 GHz exceeds 5.
• the in-plane orientation of the flat powder sheet as the average particle diameter of the flame retardant decreases. Becomes better, so that the ⁇ ′ ′ value at 10 GHz also becomes larger.
• each flat alloy powder 20 parts by mass of polybutyral resin (softening point: about 70 ° C.), 50 parts by mass of butyl acetate, and 5 parts by mass of magnesium hydroxide having an average particle diameter of 6 ⁇ m as a flame retardant Parts and 1 part by mass of red phosphorus having an average particle diameter of 6 ⁇ m were mixed by a planetary mixing and stirring apparatus to prepare a slurry (Inventive Examples 26 and 27).
• these slurries were processed into a sheet-like molded body on a polyethylene terephthalate film by a doctor blade method. Then, the noise suppression sheet
• the average particle diameter of the flame retardant is 8 ⁇ m or less, and the density of the noise suppression sheet is 2.7 g / cm 3 or more.
• the frequency of the above was in the range of 1 to 10 MHz, and the ⁇ ′ ′ value at 10 GHz exceeded 2.
• the flat powder Orientation in the sheet plane was further improved, and the ⁇ ′ ′ value at 10 GHz exceeded 5.
• the alloy powder was taken out of the solution and dried in the atmosphere at 150 ° C. for 8 hours to form an oxide having an average particle diameter of 100 nm or less on the surface of the alloy powder. Thereafter, annealing was performed in nitrogen at 350 to 450 ° C. for 30 minutes. Table 4 shows the phase structure and the coercivity measured by the method described above.
• the ⁇ ′ ′ value starts to rise, ⁇ ′ ′ value is 1
• the above frequency is in the range of 1 to 10 MHz, and the ⁇ ′ ′ value at 10 GHz is more than 2.
• the total substitution amount of Al, Co, Ni, Cr, Nb, Mo, Ta, W to Fe is In the invention examples 28, 30, 32, 34 of 3 atomic% or less, the ⁇ ′ ′ value at 10 GHz was a high value of 2.5 or more.
• the magnetic flux density of the alloy powder is reduced when the total of the substitution amounts of Al, Co, Ni, Cr, Nb, Mo, Ta, W with respect to Fe exceeds 3 atomic%, More preferably, the total of the substitutional amounts of Al, Co, Ni, Cr, Nb, Mo, Ta and W with respect to is 3 atomic% or less.
• a near-field noise suppression sheet capable of coping with magnetic field noise in a broad band of MHz to GHz band and also having flame retardancy.

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