WO2021039477A1 - Electromagnetic wave absorbing material - Google Patents
Electromagnetic wave absorbing material Download PDFInfo
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- WO2021039477A1 WO2021039477A1 PCT/JP2020/031032 JP2020031032W WO2021039477A1 WO 2021039477 A1 WO2021039477 A1 WO 2021039477A1 JP 2020031032 W JP2020031032 W JP 2020031032W WO 2021039477 A1 WO2021039477 A1 WO 2021039477A1
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- filler
- electromagnetic wave
- absorbing material
- conductive filler
- wave absorbing
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/90—Carbides
- C01B32/914—Carbides of single elements
- C01B32/956—Silicon carbide
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- 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
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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
Definitions
- the present invention relates to a radio wave absorbing material.
- Patent Document 1 a space-filling material for absorbing electromagnetic radiation, the space-filling material is heat-conducting, and the space-filling material is dispersed in a binder material and the binder material.
- a gap-filling material containing at least one magnetic filler has been disclosed.
- Patent Document 1 aims at improving the electromagnetic wave absorption effect and the thermal conductivity, but it is not highly compatible with each other. Therefore, the technique of Patent Document 1 has a problem that electromagnetic wave absorption in a high frequency band cannot be performed.
- an object of the present invention is to provide a radio wave absorbing material having electromagnetic wave absorption performance in a high frequency band, which has both electromagnetic wave absorption and thermal conductivity.
- the present invention is a medium and The semiconductor filler dispersed in the medium and Insulating thermal conductive filler dispersed in the medium, It is an electromagnetic wave absorbing material having a conductive filler dispersed in the medium.
- the total volume ratio of the semiconductor filler and the insulating heat conductive filler to the medium contained in the electromagnetic wave absorbing material ⁇ (the semiconductor filler + the insulating heat conductive filler) / the medium ⁇ . May be 1 or more.
- the volume ratio of the semiconductor filler to the insulating heat conductive filler (the semiconductor filler / the insulating heat conductive filler) contained in the electromagnetic wave absorbing material is 0.7 or more and 1.5 or less. May be good.
- the volume ratio of the conductive filler to the semiconductor filler (the conductive filler / the semiconductor filler) contained in the electromagnetic wave absorbing material may be 0.09 or more and 0.2 or less.
- the semiconductor filler may be one or more selected from SiC and Si.
- the insulating heat conductive filler may be one or more selected from Al 2 O 3 , MgO, Al N, BN and metal carbonate.
- the conductive filler may be one or more selected from carbon and titanium oxide (including those having ITO or ATO on their surfaces).
- radio wave absorbing material having both electromagnetic wave absorption and thermal conductivity and having electromagnetic wave absorption performance in a high frequency band.
- the present invention is a medium and The semiconductor filler dispersed in the medium and Insulating thermal conductive filler dispersed in the medium, It is an electromagnetic wave absorbing material having a conductive filler dispersed in the medium.
- the radio wave absorbing material according to the present invention the physical properties of the radio wave absorbing material, and the mechanism of action of the physical properties will be described in order.
- the radio wave absorbing material according to the present invention may be in a solid form (for example, a molded body, a sheet form, a tape form) or a semi-fluid form (for example, a grease form, a gel form, a paste form).
- the medium according to the present invention is not particularly limited, and when the radio wave absorbing material is in a solid state, a resin is used, and when the radio wave absorbing material is a semi-fluid material, silicone oil, mineral oil, plant-derived oil, and the like. Examples include cured gels.
- a semiconductor filler of the present invention room temperature (20 ° C.) electric resistivity at the 10 1 ( ⁇ ⁇ m) or more, refers to filler is less than 10 6 ( ⁇ ⁇ m).
- Specific examples include group IV semiconductors (Si and Ge compounds, etc.), II-VI group semiconductors (ZnSe, CdS, ZnO, etc.), III-V group semiconductors (GaAs, InP, GaN, etc.), and Group IV compound semiconductors (GaAs, InP, GaN, etc.). (SiC, SiGe, etc.) and I-III-VI group semiconductors (calcopyrite- based semiconductors such as CuInSe 2 ) can be mentioned.
- SiC and Si can be mentioned.
- the electrical resistivity in the present specification is measured by a powder resistance measurement system (MCP-PD51, manufactured by Dia Instruments) and a resistivity meter (4-terminal 4-probe method, Loresta-GP, manufactured by Mitsubishi Chemical Analytech Co., Ltd.). ) was used for measurement under the conditions of 1.0 g of sample, 3 mm of electrode spacing, 10.0 mm of sample radius, and 20 kN of load.
- the average particle size of the semiconductor filler is not particularly limited, but when the average particle size is 100 nm to 500 ⁇ m, the dispersibility in the medium is excellent, and it becomes easy to balance the radio wave absorption and the thermal conductivity.
- the average particle size of the semiconductor filler is determined by, for example, taking out the semiconductor filler contained in the medium from the medium as needed, embedding it in a resin or the like, forming a cross section, and then observing with a scanning electron microscope. The average particle size may be obtained from the average of the equivalent circle diameters of the particles.
- the shape of the semiconductor filler can be spherical, amorphous, needle-shaped, or the like, regardless of the shape.
- the semiconductor filler has a function of increasing thermal conductivity and radio wave absorption.
- Insulating thermally conductive filler is the electrical resistivity at room temperature (20 ° C.) is 10 6 ( ⁇ ⁇ m) or more and the thermal conductivity at room temperature (20 ° C.) is 2.0W / M ⁇ K or more (in order of preference, 10 W / m ⁇ K or more, 20 W / m ⁇ K or more, 23 W / m ⁇ K or more, 30 W / m ⁇ K or more, 40 W / m ⁇ K or more, 50 W / m ⁇ K , 60 W / m ⁇ K or more).
- oxides such as alumina and magnesia, nitrides such as boron nitride and aluminum nitride, metal hydroxides such as aluminum hydroxide, and metal carbonates such as diamond, magnesium carbonate and calcium carbonate. it can.
- Preferred examples include alumina, magnesia, aluminum nitride, and boron nitride.
- the average particle size of the insulating heat conductive filler is not particularly limited, but when the average particle size is 100 nm to 500 ⁇ m, the dispersibility in the medium is excellent, and it becomes easy to balance the radio wave absorption and the heat conductivity.
- the shape of the insulating heat conductive filler can be used regardless of the shape, such as spherical, amorphous, or needle-shaped.
- the average particle size of the insulating heat conductive filler is observed with a scanning electron microscope, for example, after the insulating heat conductive filler contained in the medium is taken out from the medium as necessary, embedded in a resin or the like, cross-sectionald, and then cross-sectionald. Is performed, and the average particle size may be obtained from the average of the equivalent circle diameters of, for example, 100 particles of the insulating heat conductive filler.
- the composition of the insulating thermal conductive filler contained in the medium is confirmed, and the bulk body having the same composition is JIS A1412-2: 1999 (thermal resistance and heat of the thermal insulating material).
- Conductivity measurement method-Part 2 Heat flow metering method (HFM method)), using a thermal conductivity measuring device, the time required for the test to be steady is 15 minutes or more, standard plate type EPS, high temperature surface Under the conditions of a temperature of 30 ° C., a low temperature surface temperature of 10 ° C., and a sample average temperature of 20 ° C., a method may be used in which both main surfaces of the sample are arranged so as to face in the vertical direction and measured by a thermal flow meter method.
- the thermal conductivity measuring device Autolambda HC-074 (manufactured by Eiko Seiki Co., Ltd.) is preferable.
- a laser flash method conforming to JIS R1611 may be used.
- the insulating thermal conductive filler has a function of increasing thermal conductivity.
- Conductive filler according to the present invention refers to a filler electrical resistivity is less than 10 1 ( ⁇ ⁇ m) at room temperature (20 ° C.). Specific examples include acicular titanium oxide, Ketjen black, which are conductively treated with carbon, graphite, carbon nanofibers, carbon nanotubes, ITO, etc., and fillers which are conductively treated with ITO, ATO, etc. on a base material other than metal. Can be mentioned.
- the average particle size of the conductive filler is not particularly limited, but is preferably an average particle size of 30 nm to 100 ⁇ m. When the average particle size is in this range, the dispersibility in the medium is excellent, and it becomes easy to balance the radio wave absorption and the thermal conductivity.
- the average particle size of the conductive filler for example, the conductive filler contained in the medium is taken out from the medium as needed, embedded in a resin or the like, cross-sectioned, and then observed with a scanning electron microscope to obtain conductivity.
- the average particle size may be obtained from the average of the equivalent circle diameters of the filler, for example, 100 particles.
- the shape of the conductive filler can be spherical, amorphous, needle-shaped, or the like, regardless of the shape.
- the function of the conductive filler is to connect an electrical path between the semiconductor fillers and increase the resistance at which electromagnetic waves propagate, thereby optimizing the complex dielectric constant imaginary part, which is a loss component, and optimizing the radio wave absorption performance. Can be enhanced.
- the semiconductor filler, the thermally conductive filler, and the conductive filler are different from each other.
- Additives such as a curing agent, a thickener, a flame retardant, and a thixo agent may be added to the radio wave absorbing material, if necessary.
- the total volume ratio of the semiconductor filler and the insulating heat conductive filler to the medium contained in the electromagnetic wave absorbing material ⁇ (semiconductor filler + insulating heat conductive filler) / medium ⁇ is preferably 1 or more.
- the upper limit is not particularly limited (for example, 3). In the case of sheet molding, 2 or less is preferable.
- the volume ratio of the semiconductor filler to the insulating heat conductive filler (semiconductor filler / insulating heat conductive filler) contained in the electromagnetic wave absorbing material is preferably 0.7 or more and 1.5 or less.
- the volume ratio of the conductive filler to the semiconductor filler (conductive filler / semiconductor filler) contained in the electromagnetic wave absorbing material is preferably 0.09 or more and 0.2 or less.
- the radio wave absorbing material according to the present invention preferably has an absorbency of 15 dB or more, more preferably 20 dB or more at 20 to 79 GHz.
- the prepared sample had a size of 200 mm in length and 200 mm in width, and S-parameters (S11 and S21) at frequencies of 20 to 110 GHz were measured with a network analyzer (“N5225A” manufactured by Keysight). .. Further, the radio wave absorption of the sheet was calculated from the measured S11 and S21, respectively.
- the radio wave absorbing material according to the present invention preferably has a thermal conductivity of 2 W / mK or more, more preferably 3 W / mK or more.
- thermal wave analyzer (“ai-Phase mobile M3 type 1" manufactured by iPhase) ) was used to measure the thermal diffusivity, the specific heat was measured by a differential scanning calorific value measuring device (“DSC6200” manufactured by HITACHI), and the thermal diffusivity was multiplied by the specific heat and the material density to calculate the thermal conductivity.
- Water resistance is required depending on the application (for example, automobile application, mobile phone base station, etc.).
- a water-insoluble filler as the filler.
- water-insoluble means that the amount of the target substance dissolved in 100 parts by mass of water at 20 ° C. is less than 0.1 parts by mass.
- it is preferable that it is in a solid state, and in the case of an automobile application, it may be in a semi-fluid state.
- the corresponding frequency of the radio wave absorber is such that the vertically incident high frequency electromagnetic wave causes a resonance phenomenon in the absorber and the reflected wave is greatly attenuated. It is necessary to adjust the real part and the imaginary part of the complex dielectric constant in.
- an insulating heat conductive filler and a semiconductor filler are filled in the medium in order to increase the thermal conductivity. At this time, by filling the semiconductor filler, the real part, which is a capacitance component of the complex permittivity of the radio wave absorber, and the imaginary part, which is a loss component, can be increased to approach the optimum value.
- Example 1 The raw materials are silicone oil with a viscosity of 350 cP as a medium, alumina powder with an average particle diameter of 18 ⁇ m as an insulating heat conductive filler, SiC powder with an average particle diameter of 50 ⁇ m as a semiconductor filler, major axis 9.7 ⁇ m as a conductive filler, and 0 minor axis.
- a 5.5 ⁇ m ATO-coated acicular titanium oxide was used.
- Example 1 is obtained by adding 269 parts by weight of alumina powder, 187 parts by weight of SiC powder, and 25 parts by weight of a conductive filler to silicone oil as a medium, and mixing and dispersing them with a rotation mixer.
- a semi-solid radio wave absorber was prepared.
- Examples 2 to 18 and Comparative Examples 1 to 3 The radio wave absorbing materials according to Examples 2 to 18 and Comparative Examples 1 to 3 were produced according to the production method described in Example 1 with the compositions and formulations shown in Tables 1 to 4.
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Abstract
Provided is an electromagnetic wave absorbing material having both electromagnetic wave absorption properties and thermal conductivity, and having electromagnetic wave absorption performance in a high-frequency band. The electromagnetic wave absorbing material comprises: a medium; a semiconductor filler dispersed in the medium; an insulating and thermally conductive filler dispersed in the medium; and an electrically conductive filler dispersed in the medium.
Description
本発明は、電波吸収材料に関する。
The present invention relates to a radio wave absorbing material.
近年、電子機器の高性能化・小型化に伴い、より高周波帯（２０ＧＨｚ～）へのノイズ対策部材が求められていると共に、素子の発熱に対する熱伝導部材への需要も高まっている。そして、電子機器の電磁波ノイズ対策として、ノイズ源近傍に電波吸収体を配置する手法が提案されている。
In recent years, with the increase in performance and miniaturization of electronic devices, noise countermeasure members for higher frequency bands (20 GHz and above) have been demanded, and the demand for heat conductive members for heat generation of elements has also increased. Then, as a countermeasure against electromagnetic noise of electronic devices, a method of arranging an electromagnetic wave absorber near the noise source has been proposed.
例えば、特許文献１には、電磁放射線の吸収用填隙性材料であって、該填隙性材料が熱伝 導性であり、該填隙性材料が結合剤材料及び該結合剤材料に分散されている少なくとも１種の磁性充填剤を含む填隙性材料が開示されている。
For example, in Patent Document 1, a space-filling material for absorbing electromagnetic radiation, the space-filling material is heat-conducting, and the space-filling material is dispersed in a binder material and the binder material. A gap-filling material containing at least one magnetic filler has been disclosed.
ところで、一般に電磁波吸収効果と熱伝導率向上とはトレードオフの関係にある。特許文献１の技術は、電磁波吸収効果と熱伝導率向上とを目指したものであるが、高度には両立できていない。したがって、特許文献１の技術では、高周波帯域の電磁波吸収を実施することは出来ないという課題がある。
By the way, in general, there is a trade-off relationship between the electromagnetic wave absorption effect and the improvement of thermal conductivity. The technique of Patent Document 1 aims at improving the electromagnetic wave absorption effect and the thermal conductivity, but it is not highly compatible with each other. Therefore, the technique of Patent Document 1 has a problem that electromagnetic wave absorption in a high frequency band cannot be performed.
そこで、本発明は、電磁波吸収と熱伝導性とを兼ね備えた、高周波帯域の電磁波吸収性能を有する電波吸収材料を提供することを課題とする。
Therefore, an object of the present invention is to provide a radio wave absorbing material having electromagnetic wave absorption performance in a high frequency band, which has both electromagnetic wave absorption and thermal conductivity.
本発明は、媒体と、
前記媒体に分散した半導体フィラーと、
前記媒体に分散した絶縁性熱伝導性フィラーと、
前記媒体に分散した導電性フィラーと
を有する電磁波吸収材料である。
ここで、前記電磁波吸収材料中に含まれる、前記媒体に対する前記半導体フィラーと前記絶縁性熱伝導性フィラーとの合計の体積比｛（前記半導体フィラー＋前記絶縁性熱伝導性フィラー）／前記媒体｝が１以上であってもよい。
また、前記電磁波吸収材料中に含まれる、前記絶縁性熱伝導性フィラーに対する前記半導体フィラーの体積比（前記半導体フィラー／前記絶縁性熱伝導性フィラー）が０．７以上１．５以下であってもよい。
また、前記電磁波吸収材料中に含まれる、前記半導体フィラーに対する前記導電性フィラーの体積比（前記導電性フィラー／前記半導体フィラー）が、０．０９以上０．２以下であってもよい。
また、前記半導体フィラーが、ＳｉＣ及びＳｉから選択される１種以上であってもよい。
また、前記絶縁性熱伝導性フィラーが、Ａｌ２Ｏ３、ＭｇＯ、ＡｌＮ、ＢＮ及び金属炭酸塩から選択される１種以上であってもよい。
また、前記導電性フィラーが、カーボン及び酸化チタン（これらの表面にＩＴＯやＡＴＯを有するものを含む）から選択される１種以上であってもよい。 The present invention is a medium and
The semiconductor filler dispersed in the medium and
Insulating thermal conductive filler dispersed in the medium,
It is an electromagnetic wave absorbing material having a conductive filler dispersed in the medium.
Here, the total volume ratio of the semiconductor filler and the insulating heat conductive filler to the medium contained in the electromagnetic wave absorbing material {(the semiconductor filler + the insulating heat conductive filler) / the medium}. May be 1 or more.
Further, the volume ratio of the semiconductor filler to the insulating heat conductive filler (the semiconductor filler / the insulating heat conductive filler) contained in the electromagnetic wave absorbing material is 0.7 or more and 1.5 or less. May be good.
Further, the volume ratio of the conductive filler to the semiconductor filler (the conductive filler / the semiconductor filler) contained in the electromagnetic wave absorbing material may be 0.09 or more and 0.2 or less.
Further, the semiconductor filler may be one or more selected from SiC and Si.
Further, the insulating heat conductive filler may be one or more selected from Al 2 O 3 , MgO, Al N, BN and metal carbonate.
Further, the conductive filler may be one or more selected from carbon and titanium oxide (including those having ITO or ATO on their surfaces).
前記媒体に分散した半導体フィラーと、
前記媒体に分散した絶縁性熱伝導性フィラーと、
前記媒体に分散した導電性フィラーと
を有する電磁波吸収材料である。
ここで、前記電磁波吸収材料中に含まれる、前記媒体に対する前記半導体フィラーと前記絶縁性熱伝導性フィラーとの合計の体積比｛（前記半導体フィラー＋前記絶縁性熱伝導性フィラー）／前記媒体｝が１以上であってもよい。
また、前記電磁波吸収材料中に含まれる、前記絶縁性熱伝導性フィラーに対する前記半導体フィラーの体積比（前記半導体フィラー／前記絶縁性熱伝導性フィラー）が０．７以上１．５以下であってもよい。
また、前記電磁波吸収材料中に含まれる、前記半導体フィラーに対する前記導電性フィラーの体積比（前記導電性フィラー／前記半導体フィラー）が、０．０９以上０．２以下であってもよい。
また、前記半導体フィラーが、ＳｉＣ及びＳｉから選択される１種以上であってもよい。
また、前記絶縁性熱伝導性フィラーが、Ａｌ２Ｏ３、ＭｇＯ、ＡｌＮ、ＢＮ及び金属炭酸塩から選択される１種以上であってもよい。
また、前記導電性フィラーが、カーボン及び酸化チタン（これらの表面にＩＴＯやＡＴＯを有するものを含む）から選択される１種以上であってもよい。 The present invention is a medium and
The semiconductor filler dispersed in the medium and
Insulating thermal conductive filler dispersed in the medium,
It is an electromagnetic wave absorbing material having a conductive filler dispersed in the medium.
Here, the total volume ratio of the semiconductor filler and the insulating heat conductive filler to the medium contained in the electromagnetic wave absorbing material {(the semiconductor filler + the insulating heat conductive filler) / the medium}. May be 1 or more.
Further, the volume ratio of the semiconductor filler to the insulating heat conductive filler (the semiconductor filler / the insulating heat conductive filler) contained in the electromagnetic wave absorbing material is 0.7 or more and 1.5 or less. May be good.
Further, the volume ratio of the conductive filler to the semiconductor filler (the conductive filler / the semiconductor filler) contained in the electromagnetic wave absorbing material may be 0.09 or more and 0.2 or less.
Further, the semiconductor filler may be one or more selected from SiC and Si.
Further, the insulating heat conductive filler may be one or more selected from Al 2 O 3 , MgO, Al N, BN and metal carbonate.
Further, the conductive filler may be one or more selected from carbon and titanium oxide (including those having ITO or ATO on their surfaces).
本発明によれば、電磁波吸収と熱伝導性とを兼ね備えた、高周波帯域の電磁波吸収性能を有する電波吸収材料を提供することが可能となる。
According to the present invention, it is possible to provide a radio wave absorbing material having both electromagnetic wave absorption and thermal conductivity and having electromagnetic wave absorption performance in a high frequency band.
本発明は、媒体と、
前記媒体に分散した半導体フィラーと、
前記媒体に分散した絶縁性熱伝導性フィラーと、
前記媒体に分散した導電性フィラーと
を有する電磁波吸収材料である。以下、本発明に係る電波吸収材料、当該電波吸収材料の物性、当該物性の作用機序について順に説明する。 The present invention is a medium and
The semiconductor filler dispersed in the medium and
Insulating thermal conductive filler dispersed in the medium,
It is an electromagnetic wave absorbing material having a conductive filler dispersed in the medium. Hereinafter, the radio wave absorbing material according to the present invention, the physical properties of the radio wave absorbing material, and the mechanism of action of the physical properties will be described in order.
前記媒体に分散した半導体フィラーと、
前記媒体に分散した絶縁性熱伝導性フィラーと、
前記媒体に分散した導電性フィラーと
を有する電磁波吸収材料である。以下、本発明に係る電波吸収材料、当該電波吸収材料の物性、当該物性の作用機序について順に説明する。 The present invention is a medium and
The semiconductor filler dispersed in the medium and
Insulating thermal conductive filler dispersed in the medium,
It is an electromagnetic wave absorbing material having a conductive filler dispersed in the medium. Hereinafter, the radio wave absorbing material according to the present invention, the physical properties of the radio wave absorbing material, and the mechanism of action of the physical properties will be described in order.
≪１．電波吸収材料≫
＜１－１．形態＞
本発明に係る電波吸収材料は、固体状（例えば、成形体、シート状、テープ状）でも半流動体（例えば、グリース状、ゲル状、ペースト状）でもよい。 ≪1. Radio wave absorbing material ≫
<1-1. Form>
The radio wave absorbing material according to the present invention may be in a solid form (for example, a molded body, a sheet form, a tape form) or a semi-fluid form (for example, a grease form, a gel form, a paste form).
＜１－１．形態＞
本発明に係る電波吸収材料は、固体状（例えば、成形体、シート状、テープ状）でも半流動体（例えば、グリース状、ゲル状、ペースト状）でもよい。 ≪1. Radio wave absorbing material ≫
<1-1. Form>
The radio wave absorbing material according to the present invention may be in a solid form (for example, a molded body, a sheet form, a tape form) or a semi-fluid form (for example, a grease form, a gel form, a paste form).
＜１－２．成分＞
（１－２－１．媒体）
本発明に係る媒体は、特に限定されず、電波吸収材料が固体状である場合には樹脂、電波吸収材料が半流動体である場合にはシリコーンオイル、鉱物油、植物由来油、これらを半硬化させたゲルを挙げることができる。 <1-2. Ingredients>
(1-2-1. Medium)
The medium according to the present invention is not particularly limited, and when the radio wave absorbing material is in a solid state, a resin is used, and when the radio wave absorbing material is a semi-fluid material, silicone oil, mineral oil, plant-derived oil, and the like. Examples include cured gels.
（１－２－１．媒体）
本発明に係る媒体は、特に限定されず、電波吸収材料が固体状である場合には樹脂、電波吸収材料が半流動体である場合にはシリコーンオイル、鉱物油、植物由来油、これらを半硬化させたゲルを挙げることができる。 <1-2. Ingredients>
(1-2-1. Medium)
The medium according to the present invention is not particularly limited, and when the radio wave absorbing material is in a solid state, a resin is used, and when the radio wave absorbing material is a semi-fluid material, silicone oil, mineral oil, plant-derived oil, and the like. Examples include cured gels.
（１－２－２．半導体フィラー）
本発明に係る半導体フィラーは、常温（２０℃）での電気抵抗率が１０１（Ω・ｍ）以上、１０６（Ω・ｍ）未満であるフィラーを指す。具体例としては、IV族半導体（ＳｉやＧｅの化合物等）、II-VI族半導体（ＺｎＳｅ、ＣｄＳ、ＺｎＯ等）、III－V族半導体（ＧａＡｓ、ＩｎＰ、ＧａＮ等）、IV族化合物半導体（ＳｉＣ、ＳｉＧｅ等）、I－III－VI族半導体（ＣｕＩｎＳｅ２などのカルコパイライト系半導体等）を挙げることができる。好ましくはＳｉＣ、Ｓｉを挙げることができる。尚、本明細書における電気抵抗率の測定は、粉体抵抗測定システム（ＭＣＰ－ＰＤ５１、ダイアインスツルメンツ社製）及び抵抗率計（４端子４探針方式、ロレスタ－ＧＰ、三菱化学アナリテック社製）を使用して、試料１．０ｇ、電極間隔３ｍｍ、試料半径１０．０ｍｍ、荷重２０ｋＮの条件にて測定することにより行った。 (1-2-2. Semiconductor filler)
A semiconductor filler of the present invention, room temperature (20 ° C.) electric resistivity at the 10 1 (Ω · m) or more, refers to filler is less than 10 6 (Ω · m). Specific examples include group IV semiconductors (Si and Ge compounds, etc.), II-VI group semiconductors (ZnSe, CdS, ZnO, etc.), III-V group semiconductors (GaAs, InP, GaN, etc.), and Group IV compound semiconductors (GaAs, InP, GaN, etc.). (SiC, SiGe, etc.) and I-III-VI group semiconductors (calcopyrite- based semiconductors such as CuInSe 2 ) can be mentioned. Preferably, SiC and Si can be mentioned. The electrical resistivity in the present specification is measured by a powder resistance measurement system (MCP-PD51, manufactured by Dia Instruments) and a resistivity meter (4-terminal 4-probe method, Loresta-GP, manufactured by Mitsubishi Chemical Analytech Co., Ltd.). ) Was used for measurement under the conditions of 1.0 g of sample, 3 mm of electrode spacing, 10.0 mm of sample radius, and 20 kN of load.
本発明に係る半導体フィラーは、常温（２０℃）での電気抵抗率が１０１（Ω・ｍ）以上、１０６（Ω・ｍ）未満であるフィラーを指す。具体例としては、IV族半導体（ＳｉやＧｅの化合物等）、II-VI族半導体（ＺｎＳｅ、ＣｄＳ、ＺｎＯ等）、III－V族半導体（ＧａＡｓ、ＩｎＰ、ＧａＮ等）、IV族化合物半導体（ＳｉＣ、ＳｉＧｅ等）、I－III－VI族半導体（ＣｕＩｎＳｅ２などのカルコパイライト系半導体等）を挙げることができる。好ましくはＳｉＣ、Ｓｉを挙げることができる。尚、本明細書における電気抵抗率の測定は、粉体抵抗測定システム（ＭＣＰ－ＰＤ５１、ダイアインスツルメンツ社製）及び抵抗率計（４端子４探針方式、ロレスタ－ＧＰ、三菱化学アナリテック社製）を使用して、試料１．０ｇ、電極間隔３ｍｍ、試料半径１０．０ｍｍ、荷重２０ｋＮの条件にて測定することにより行った。 (1-2-2. Semiconductor filler)
A semiconductor filler of the present invention, room temperature (20 ° C.) electric resistivity at the 10 1 (Ω · m) or more, refers to filler is less than 10 6 (Ω · m). Specific examples include group IV semiconductors (Si and Ge compounds, etc.), II-VI group semiconductors (ZnSe, CdS, ZnO, etc.), III-V group semiconductors (GaAs, InP, GaN, etc.), and Group IV compound semiconductors (GaAs, InP, GaN, etc.). (SiC, SiGe, etc.) and I-III-VI group semiconductors (calcopyrite- based semiconductors such as CuInSe 2 ) can be mentioned. Preferably, SiC and Si can be mentioned. The electrical resistivity in the present specification is measured by a powder resistance measurement system (MCP-PD51, manufactured by Dia Instruments) and a resistivity meter (4-terminal 4-probe method, Loresta-GP, manufactured by Mitsubishi Chemical Analytech Co., Ltd.). ) Was used for measurement under the conditions of 1.0 g of sample, 3 mm of electrode spacing, 10.0 mm of sample radius, and 20 kN of load.
半導体フィラーの平均粒子径は、特に限定されないが、平均粒子径１００ｎｍ～５００μｍであると媒体への分散性に優れ、電波吸収性と熱伝導性のバランスを取りやすくなる。半導体フィラーの平均粒子径は、例えば媒体に含まれる半導体フィラーを必要に応じて媒体から取り出し、樹脂等に包埋後、断面化した後に、走査型電子顕微鏡による観察を実施し、半導体フィラー例えば１００粒子の円相当径の平均から、平均粒子径を求めればよい。半導体フィラーの形状は、球状、不定形、針状等、形状に係わらず用いることができる。
半導体フィラーは、熱伝導率と電波吸収性を高める機能を有する。 The average particle size of the semiconductor filler is not particularly limited, but when the average particle size is 100 nm to 500 μm, the dispersibility in the medium is excellent, and it becomes easy to balance the radio wave absorption and the thermal conductivity. The average particle size of the semiconductor filler is determined by, for example, taking out the semiconductor filler contained in the medium from the medium as needed, embedding it in a resin or the like, forming a cross section, and then observing with a scanning electron microscope. The average particle size may be obtained from the average of the equivalent circle diameters of the particles. The shape of the semiconductor filler can be spherical, amorphous, needle-shaped, or the like, regardless of the shape.
The semiconductor filler has a function of increasing thermal conductivity and radio wave absorption.
半導体フィラーは、熱伝導率と電波吸収性を高める機能を有する。 The average particle size of the semiconductor filler is not particularly limited, but when the average particle size is 100 nm to 500 μm, the dispersibility in the medium is excellent, and it becomes easy to balance the radio wave absorption and the thermal conductivity. The average particle size of the semiconductor filler is determined by, for example, taking out the semiconductor filler contained in the medium from the medium as needed, embedding it in a resin or the like, forming a cross section, and then observing with a scanning electron microscope. The average particle size may be obtained from the average of the equivalent circle diameters of the particles. The shape of the semiconductor filler can be spherical, amorphous, needle-shaped, or the like, regardless of the shape.
The semiconductor filler has a function of increasing thermal conductivity and radio wave absorption.
（１－２－３．絶縁性熱伝導性フィラー）
本発明に係る絶縁性熱伝導性フィラーは、常温（２０℃）での電気抵抗率が１０６（Ω・ｍ）以上であり、且つ、常温（２０℃）での熱伝導率が２．０Ｗ／ｍ・Ｋ以上（好適な順に、１０Ｗ／ｍ・Ｋ以上、２０Ｗ／ｍ・Ｋ以上、２３Ｗ／ｍ・Ｋ以上、３０Ｗ／ｍ・Ｋ以上、４０Ｗ／ｍ・Ｋ以上、５０Ｗ／ｍ・Ｋ、６０Ｗ／ｍ・Ｋ以上）であるフィラーを指す。具体例としては、アルミナ、マグネシア等の酸化物、窒化ホウ素、窒化アルミニウム等の窒化物、水酸化アルミニウム等の金属水酸化物、ダイヤモンド、炭酸マグネシウム、炭酸カルシウム等の金属炭酸塩等を挙げることができる。好ましくは、アルミナ、マグネシア、窒化アルミニウム、窒化ホウ素を挙げることができる。絶縁性熱伝導性フィラーの平均粒子径は、特に限定されないが、平均粒子径１００ｎｍ～５００μｍであると媒体への分散性に優れ、電波吸収性と熱伝導性のバランスを取りやすくなる。絶縁性熱伝導性フィラーの形状は、球状、不定形、針状等、形状に係わらず用いることができる。 (1-2-3. Insulating thermal conductive filler)
Insulating thermally conductive filler according to the present invention is the electrical resistivity at room temperature (20 ° C.) is 10 6 (Ω · m) or more and the thermal conductivity at room temperature (20 ° C.) is 2.0W / M ・ K or more (in order of preference, 10 W / m ・ K or more, 20 W / m ・ K or more, 23 W / m ・ K or more, 30 W / m ・ K or more, 40 W / m ・ K or more, 50 W / m ・ K , 60 W / m · K or more). Specific examples include oxides such as alumina and magnesia, nitrides such as boron nitride and aluminum nitride, metal hydroxides such as aluminum hydroxide, and metal carbonates such as diamond, magnesium carbonate and calcium carbonate. it can. Preferred examples include alumina, magnesia, aluminum nitride, and boron nitride. The average particle size of the insulating heat conductive filler is not particularly limited, but when the average particle size is 100 nm to 500 μm, the dispersibility in the medium is excellent, and it becomes easy to balance the radio wave absorption and the heat conductivity. The shape of the insulating heat conductive filler can be used regardless of the shape, such as spherical, amorphous, or needle-shaped.
本発明に係る絶縁性熱伝導性フィラーは、常温（２０℃）での電気抵抗率が１０６（Ω・ｍ）以上であり、且つ、常温（２０℃）での熱伝導率が２．０Ｗ／ｍ・Ｋ以上（好適な順に、１０Ｗ／ｍ・Ｋ以上、２０Ｗ／ｍ・Ｋ以上、２３Ｗ／ｍ・Ｋ以上、３０Ｗ／ｍ・Ｋ以上、４０Ｗ／ｍ・Ｋ以上、５０Ｗ／ｍ・Ｋ、６０Ｗ／ｍ・Ｋ以上）であるフィラーを指す。具体例としては、アルミナ、マグネシア等の酸化物、窒化ホウ素、窒化アルミニウム等の窒化物、水酸化アルミニウム等の金属水酸化物、ダイヤモンド、炭酸マグネシウム、炭酸カルシウム等の金属炭酸塩等を挙げることができる。好ましくは、アルミナ、マグネシア、窒化アルミニウム、窒化ホウ素を挙げることができる。絶縁性熱伝導性フィラーの平均粒子径は、特に限定されないが、平均粒子径１００ｎｍ～５００μｍであると媒体への分散性に優れ、電波吸収性と熱伝導性のバランスを取りやすくなる。絶縁性熱伝導性フィラーの形状は、球状、不定形、針状等、形状に係わらず用いることができる。 (1-2-3. Insulating thermal conductive filler)
Insulating thermally conductive filler according to the present invention is the electrical resistivity at room temperature (20 ° C.) is 10 6 (Ω · m) or more and the thermal conductivity at room temperature (20 ° C.) is 2.0W / M ・ K or more (in order of preference, 10 W / m ・ K or more, 20 W / m ・ K or more, 23 W / m ・ K or more, 30 W / m ・ K or more, 40 W / m ・ K or more, 50 W / m ・ K , 60 W / m · K or more). Specific examples include oxides such as alumina and magnesia, nitrides such as boron nitride and aluminum nitride, metal hydroxides such as aluminum hydroxide, and metal carbonates such as diamond, magnesium carbonate and calcium carbonate. it can. Preferred examples include alumina, magnesia, aluminum nitride, and boron nitride. The average particle size of the insulating heat conductive filler is not particularly limited, but when the average particle size is 100 nm to 500 μm, the dispersibility in the medium is excellent, and it becomes easy to balance the radio wave absorption and the heat conductivity. The shape of the insulating heat conductive filler can be used regardless of the shape, such as spherical, amorphous, or needle-shaped.
絶縁性熱伝導性フィラーの平均粒子径は、例えば媒体に含まれる絶縁性熱伝導性フィラーを必要に応じて媒体から取り出し、樹脂等に包埋後、断面化した後に、走査型電子顕微鏡による観察を実施し、絶縁性熱伝導性フィラー例えば１００粒子の円相当径の平均から、平均粒子径を求めればよい。尚、本明細書における熱伝導率の測定は、媒体に含まれる絶縁性熱伝導性フィラーの組成を確認し、同組成のバルク体をＪＩＳ Ａ１４１２－２：１９９９（熱絶縁材の熱抵抗及び熱伝導率の測定方法－第２部：熱流計法（ＨＦＭ法））に準拠し、熱伝導率測定装置を用いて、試験の定常に要する時間１５分以上、標準板の種類ＥＰＳ、高温面の温度３０℃、低温面の温度１０℃、サンプル平均温度２０℃、の条件で、サンプルの両方の主面が上下方向を向くように配置し、熱流計法により測定する方法を用いればよい。熱伝導率測定装置は、オートラムダＨＣ－０７４（英弘精機社製）が好ましい。または、ＪＩＳ Ｒ１６１１に準拠したレーザーフラッシュ法によってもよい。絶縁性熱伝導性フィラーは、熱伝導性を高める機能を有する。
The average particle size of the insulating heat conductive filler is observed with a scanning electron microscope, for example, after the insulating heat conductive filler contained in the medium is taken out from the medium as necessary, embedded in a resin or the like, cross-sectionald, and then cross-sectionald. Is performed, and the average particle size may be obtained from the average of the equivalent circle diameters of, for example, 100 particles of the insulating heat conductive filler. In the measurement of the thermal conductivity in the present specification, the composition of the insulating thermal conductive filler contained in the medium is confirmed, and the bulk body having the same composition is JIS A1412-2: 1999 (thermal resistance and heat of the thermal insulating material). Conductivity measurement method-Part 2: Heat flow metering method (HFM method)), using a thermal conductivity measuring device, the time required for the test to be steady is 15 minutes or more, standard plate type EPS, high temperature surface Under the conditions of a temperature of 30 ° C., a low temperature surface temperature of 10 ° C., and a sample average temperature of 20 ° C., a method may be used in which both main surfaces of the sample are arranged so as to face in the vertical direction and measured by a thermal flow meter method. As the thermal conductivity measuring device, Autolambda HC-074 (manufactured by Eiko Seiki Co., Ltd.) is preferable. Alternatively, a laser flash method conforming to JIS R1611 may be used. The insulating thermal conductive filler has a function of increasing thermal conductivity.
（１－２－４．導電性フィラー）
本発明に係る導電性フィラーは、常温（２０℃）での電気抵抗率が１０１（Ω・ｍ）未満であるフィラーを指す。具体例としては、カーボン、グラファイト、カーボンナノファイバ、カーボンナノチューブ、ＩＴＯ等で導電処理された針状酸化チタン、ケッチェンブラック、金属以外の基材にＩＴＯ、ＡＴＯ等で導電処理されたフィラー等を挙げることができる。 (1-2-4. Conductive filler)
Conductive filler according to the present invention refers to a filler electrical resistivity is less than 10 1 (Ω · m) at room temperature (20 ° C.). Specific examples include acicular titanium oxide, Ketjen black, which are conductively treated with carbon, graphite, carbon nanofibers, carbon nanotubes, ITO, etc., and fillers which are conductively treated with ITO, ATO, etc. on a base material other than metal. Can be mentioned.
本発明に係る導電性フィラーは、常温（２０℃）での電気抵抗率が１０１（Ω・ｍ）未満であるフィラーを指す。具体例としては、カーボン、グラファイト、カーボンナノファイバ、カーボンナノチューブ、ＩＴＯ等で導電処理された針状酸化チタン、ケッチェンブラック、金属以外の基材にＩＴＯ、ＡＴＯ等で導電処理されたフィラー等を挙げることができる。 (1-2-4. Conductive filler)
Conductive filler according to the present invention refers to a filler electrical resistivity is less than 10 1 (Ω · m) at room temperature (20 ° C.). Specific examples include acicular titanium oxide, Ketjen black, which are conductively treated with carbon, graphite, carbon nanofibers, carbon nanotubes, ITO, etc., and fillers which are conductively treated with ITO, ATO, etc. on a base material other than metal. Can be mentioned.
導電性フィラーの平均粒子径は、特に限定されないが、平均粒子径３０ｎｍ～１００μｍであることが好ましい。この範囲の平均粒子径であると、媒体への分散性に優れ、電波吸収性と熱伝導性のバランスを取りやすくなる。導電性フィラーの平均粒子径は、例えば媒体に含まれる導電性フィラーを必要に応じて媒体から取り出し、樹脂等に包埋後、断面化した後に、走査型電子顕微鏡による観察を実施し、導電性フィラー例えば１００粒子の円相当径の平均から、平均粒子径を求めればよい。導電性フィラーの形状は、球状、不定形、針状等、形状に係わらず用いることができる。導電性フィラーの機能としては、半導体フィラー間に電気的なパスを繋ぎ、電磁波が伝播する抵抗を高めることで損失成分である複素誘電率虚部を意図的に高めることで最適化し、電波吸収性能を高めることができる。
The average particle size of the conductive filler is not particularly limited, but is preferably an average particle size of 30 nm to 100 μm. When the average particle size is in this range, the dispersibility in the medium is excellent, and it becomes easy to balance the radio wave absorption and the thermal conductivity. For the average particle size of the conductive filler, for example, the conductive filler contained in the medium is taken out from the medium as needed, embedded in a resin or the like, cross-sectioned, and then observed with a scanning electron microscope to obtain conductivity. The average particle size may be obtained from the average of the equivalent circle diameters of the filler, for example, 100 particles. The shape of the conductive filler can be spherical, amorphous, needle-shaped, or the like, regardless of the shape. The function of the conductive filler is to connect an electrical path between the semiconductor fillers and increase the resistance at which electromagnetic waves propagate, thereby optimizing the complex dielectric constant imaginary part, which is a loss component, and optimizing the radio wave absorption performance. Can be enhanced.
尚、半導体フィラー、熱伝導性フィラー及び導電性フィラーは、相互に異なるものである。
Note that the semiconductor filler, the thermally conductive filler, and the conductive filler are different from each other.
（１－２－５．他の成分）
該電波吸収材料には、必要に応じて添加剤、例えば、硬化剤、増粘剤、難燃剤、チクソ剤等を添加してもよい。 (1-2-5. Other ingredients)
Additives such as a curing agent, a thickener, a flame retardant, and a thixo agent may be added to the radio wave absorbing material, if necessary.
該電波吸収材料には、必要に応じて添加剤、例えば、硬化剤、増粘剤、難燃剤、チクソ剤等を添加してもよい。 (1-2-5. Other ingredients)
Additives such as a curing agent, a thickener, a flame retardant, and a thixo agent may be added to the radio wave absorbing material, if necessary.
＜１－３．含有比＞
（１－３－１．｛（半導体フィラー＋絶縁性熱伝導性フィラー）／媒体｝）
電磁波吸収材料中に含まれる、媒体に対する半導体フィラーと絶縁性熱伝導性フィラーとの合計の体積比｛（半導体フィラー＋絶縁性熱伝導性フィラー）／媒体｝は、１以上が好適である。上限は特に限定されない（例えば３）。尚、シート成形の場合には、２以下が好適である。 <1-3. Content ratio>
(1-3-1. {(Semiconductor filler + insulating thermal conductive filler) / medium})
The total volume ratio of the semiconductor filler and the insulating heat conductive filler to the medium contained in the electromagnetic wave absorbing material {(semiconductor filler + insulating heat conductive filler) / medium} is preferably 1 or more. The upper limit is not particularly limited (for example, 3). In the case of sheet molding, 2 or less is preferable.
（１－３－１．｛（半導体フィラー＋絶縁性熱伝導性フィラー）／媒体｝）
電磁波吸収材料中に含まれる、媒体に対する半導体フィラーと絶縁性熱伝導性フィラーとの合計の体積比｛（半導体フィラー＋絶縁性熱伝導性フィラー）／媒体｝は、１以上が好適である。上限は特に限定されない（例えば３）。尚、シート成形の場合には、２以下が好適である。 <1-3. Content ratio>
(1-3-1. {(Semiconductor filler + insulating thermal conductive filler) / medium})
The total volume ratio of the semiconductor filler and the insulating heat conductive filler to the medium contained in the electromagnetic wave absorbing material {(semiconductor filler + insulating heat conductive filler) / medium} is preferably 1 or more. The upper limit is not particularly limited (for example, 3). In the case of sheet molding, 2 or less is preferable.
（１－３－２．半導体フィラー／絶縁性熱伝導性フィラー）
電磁波吸収材料中に含まれる、絶縁性熱伝導性フィラーに対する半導体フィラーの体積比（半導体フィラー／絶縁性熱伝導性フィラー）は、０．７以上１．５以下であることが好適である。 (1-3-2. Semiconductor filler / Insulating thermal conductive filler)
The volume ratio of the semiconductor filler to the insulating heat conductive filler (semiconductor filler / insulating heat conductive filler) contained in the electromagnetic wave absorbing material is preferably 0.7 or more and 1.5 or less.
電磁波吸収材料中に含まれる、絶縁性熱伝導性フィラーに対する半導体フィラーの体積比（半導体フィラー／絶縁性熱伝導性フィラー）は、０．７以上１．５以下であることが好適である。 (1-3-2. Semiconductor filler / Insulating thermal conductive filler)
The volume ratio of the semiconductor filler to the insulating heat conductive filler (semiconductor filler / insulating heat conductive filler) contained in the electromagnetic wave absorbing material is preferably 0.7 or more and 1.5 or less.
（１－３－３．導電性フィラー／半導体フィラー）
電磁波吸収材料中に含まれる、半導体フィラーに対する導電性フィラーの体積比（導電性フィラー／半導体フィラー）は、０．０９以上０．２以下であることが好適である。 (1-3-3. Conductive filler / semiconductor filler)
The volume ratio of the conductive filler to the semiconductor filler (conductive filler / semiconductor filler) contained in the electromagnetic wave absorbing material is preferably 0.09 or more and 0.2 or less.
電磁波吸収材料中に含まれる、半導体フィラーに対する導電性フィラーの体積比（導電性フィラー／半導体フィラー）は、０．０９以上０．２以下であることが好適である。 (1-3-3. Conductive filler / semiconductor filler)
The volume ratio of the conductive filler to the semiconductor filler (conductive filler / semiconductor filler) contained in the electromagnetic wave absorbing material is preferably 0.09 or more and 0.2 or less.
≪２．電波吸収材料の物性≫
＜２－１．電波吸収性＞
本発明に係る電波吸収材料は、好適には、２０～７９ＧＨｚにおいて、好適には１５ｄＢ以上、より好適には２０ｄＢ以上の吸収性がある。ここで、電波吸収性は、作製したサンプルを縦２００ｍｍ、横２００ｍｍのサイズとし、これをネットワークアナライザ（Ｋｅｙｓｉｇｈｔ社製「N5225A」）にて周波数20～110ＧＨｚにおけるＳパラメータ（Ｓ１１及びＳ２１）を測定した。また、測定したＳ１１及びＳ２１からシートの電波吸収性をそれぞれ算出した。 ≪2. Physical characteristics of radio wave absorbing material ≫
<2-1. Radio wave absorption>
The radio wave absorbing material according to the present invention preferably has an absorbency of 15 dB or more, more preferably 20 dB or more at 20 to 79 GHz. Here, for radio wave absorption, the prepared sample had a size of 200 mm in length and 200 mm in width, and S-parameters (S11 and S21) at frequencies of 20 to 110 GHz were measured with a network analyzer (“N5225A” manufactured by Keysight). .. Further, the radio wave absorption of the sheet was calculated from the measured S11 and S21, respectively.
＜２－１．電波吸収性＞
本発明に係る電波吸収材料は、好適には、２０～７９ＧＨｚにおいて、好適には１５ｄＢ以上、より好適には２０ｄＢ以上の吸収性がある。ここで、電波吸収性は、作製したサンプルを縦２００ｍｍ、横２００ｍｍのサイズとし、これをネットワークアナライザ（Ｋｅｙｓｉｇｈｔ社製「N5225A」）にて周波数20～110ＧＨｚにおけるＳパラメータ（Ｓ１１及びＳ２１）を測定した。また、測定したＳ１１及びＳ２１からシートの電波吸収性をそれぞれ算出した。 ≪2. Physical characteristics of radio wave absorbing material ≫
<2-1. Radio wave absorption>
The radio wave absorbing material according to the present invention preferably has an absorbency of 15 dB or more, more preferably 20 dB or more at 20 to 79 GHz. Here, for radio wave absorption, the prepared sample had a size of 200 mm in length and 200 mm in width, and S-parameters (S11 and S21) at frequencies of 20 to 110 GHz were measured with a network analyzer (“N5225A” manufactured by Keysight). .. Further, the radio wave absorption of the sheet was calculated from the measured S11 and S21, respectively.
＜２－２．熱伝導性＞
本発明に係る電波吸収材料は、好適には２Ｗ／ｍＫ以上、より好適には３Ｗ／ｍＫ以上の熱伝導率がある。ISO22007-3:2008(プラスチック－熱伝導率及び熱拡散係数の求め方－第3部：温度波分析法)に準拠し、温度波分析法装置(アイフェイズ社製「ai-Phase mobile M3 type1」)を用いて熱拡散率を測定、示差走査熱量測定装置(HITACHI社製「DSC6200」)により比熱を測定し、熱拡散率と比熱と材料密度を乗算し熱伝導率を算出した。 <2-2. Thermal conductivity>
The radio wave absorbing material according to the present invention preferably has a thermal conductivity of 2 W / mK or more, more preferably 3 W / mK or more. Based on ISO22007-3: 2008 (Plastic-How to obtain thermal conductivity and thermal diffusivity-Part 3: Thermal diffusivity), thermal wave analyzer ("ai-Phase mobile M3 type 1" manufactured by iPhase) ) Was used to measure the thermal diffusivity, the specific heat was measured by a differential scanning calorific value measuring device (“DSC6200” manufactured by HITACHI), and the thermal diffusivity was multiplied by the specific heat and the material density to calculate the thermal conductivity.
本発明に係る電波吸収材料は、好適には２Ｗ／ｍＫ以上、より好適には３Ｗ／ｍＫ以上の熱伝導率がある。ISO22007-3:2008(プラスチック－熱伝導率及び熱拡散係数の求め方－第3部：温度波分析法)に準拠し、温度波分析法装置(アイフェイズ社製「ai-Phase mobile M3 type1」)を用いて熱拡散率を測定、示差走査熱量測定装置(HITACHI社製「DSC6200」)により比熱を測定し、熱拡散率と比熱と材料密度を乗算し熱伝導率を算出した。 <2-2. Thermal conductivity>
The radio wave absorbing material according to the present invention preferably has a thermal conductivity of 2 W / mK or more, more preferably 3 W / mK or more. Based on ISO22007-3: 2008 (Plastic-How to obtain thermal conductivity and thermal diffusivity-Part 3: Thermal diffusivity), thermal wave analyzer ("ai-Phase mobile M3 type 1" manufactured by iPhase) ) Was used to measure the thermal diffusivity, the specific heat was measured by a differential scanning calorific value measuring device (“DSC6200” manufactured by HITACHI), and the thermal diffusivity was multiplied by the specific heat and the material density to calculate the thermal conductivity.
＜２－３．その他＞
用途によっては耐水性が求められる（例えば、自動車用途、携帯電話基地局等）。尚、この場合、フィラーとしては水不溶性フィラーを用いることが好適である。ここで、「水不溶性」とは、２０℃の水１００質量部に対する対象物質の溶解量が０．１質量部未満であることを意味する。また、外部環境に晒される用途の場合、固体状である方がよく、自動車用途の場合、半流動体状であってもよい。 <2-3. Others>
Water resistance is required depending on the application (for example, automobile application, mobile phone base station, etc.). In this case, it is preferable to use a water-insoluble filler as the filler. Here, "water-insoluble" means that the amount of the target substance dissolved in 100 parts by mass of water at 20 ° C. is less than 0.1 parts by mass. Further, in the case of an application exposed to the external environment, it is preferable that it is in a solid state, and in the case of an automobile application, it may be in a semi-fluid state.
用途によっては耐水性が求められる（例えば、自動車用途、携帯電話基地局等）。尚、この場合、フィラーとしては水不溶性フィラーを用いることが好適である。ここで、「水不溶性」とは、２０℃の水１００質量部に対する対象物質の溶解量が０．１質量部未満であることを意味する。また、外部環境に晒される用途の場合、固体状である方がよく、自動車用途の場合、半流動体状であってもよい。 <2-3. Others>
Water resistance is required depending on the application (for example, automobile application, mobile phone base station, etc.). In this case, it is preferable to use a water-insoluble filler as the filler. Here, "water-insoluble" means that the amount of the target substance dissolved in 100 parts by mass of water at 20 ° C. is less than 0.1 parts by mass. Further, in the case of an application exposed to the external environment, it is preferable that it is in a solid state, and in the case of an automobile application, it may be in a semi-fluid state.
≪３．作用機序≫
電波吸収性の発現には、電波吸収体を反射板に配置した際、垂直に入射した高周波電磁波が吸収体内で共振現象を起こすことで大きく反射波が減衰するように電波吸収体の対応する周波数における複素誘電率の実部と虚部と最適な値に調整する必要がある。本発明では、媒体中に熱伝導率を高めるために絶縁性の熱伝導フィラーと、半導体フィラーを媒体中に充填している。このとき、半導体フィラーを充填することで電波吸収体の複素誘電率の容量成分である実部と損失成分である虚部とを増加させ最適値に近づけることができるが、本発明ではここに加えて導電性フィラーを添加することで、半導体フィラー間に電気的なパスを繋ぎ、電磁波が伝播する抵抗を高めることで損失成分である複素誘電率虚部を意図的に高めることで最適化し、電波吸収性能を高めている。以上のような作用機序であると推定される。 ≪3. Mechanism of action ≫
To manifest the radio wave absorption, when the radio wave absorber is placed on the reflector, the corresponding frequency of the radio wave absorber is such that the vertically incident high frequency electromagnetic wave causes a resonance phenomenon in the absorber and the reflected wave is greatly attenuated. It is necessary to adjust the real part and the imaginary part of the complex dielectric constant in. In the present invention, an insulating heat conductive filler and a semiconductor filler are filled in the medium in order to increase the thermal conductivity. At this time, by filling the semiconductor filler, the real part, which is a capacitance component of the complex permittivity of the radio wave absorber, and the imaginary part, which is a loss component, can be increased to approach the optimum value. By adding a conductive filler, an electrical path is connected between the semiconductor fillers, and by increasing the resistance at which electromagnetic waves propagate, the complex permittivity imaginary part, which is a loss component, is intentionally increased to optimize the radio wave. The absorption performance is improved. It is presumed to have the above mechanism of action.
電波吸収性の発現には、電波吸収体を反射板に配置した際、垂直に入射した高周波電磁波が吸収体内で共振現象を起こすことで大きく反射波が減衰するように電波吸収体の対応する周波数における複素誘電率の実部と虚部と最適な値に調整する必要がある。本発明では、媒体中に熱伝導率を高めるために絶縁性の熱伝導フィラーと、半導体フィラーを媒体中に充填している。このとき、半導体フィラーを充填することで電波吸収体の複素誘電率の容量成分である実部と損失成分である虚部とを増加させ最適値に近づけることができるが、本発明ではここに加えて導電性フィラーを添加することで、半導体フィラー間に電気的なパスを繋ぎ、電磁波が伝播する抵抗を高めることで損失成分である複素誘電率虚部を意図的に高めることで最適化し、電波吸収性能を高めている。以上のような作用機序であると推定される。 ≪3. Mechanism of action ≫
To manifest the radio wave absorption, when the radio wave absorber is placed on the reflector, the corresponding frequency of the radio wave absorber is such that the vertically incident high frequency electromagnetic wave causes a resonance phenomenon in the absorber and the reflected wave is greatly attenuated. It is necessary to adjust the real part and the imaginary part of the complex dielectric constant in. In the present invention, an insulating heat conductive filler and a semiconductor filler are filled in the medium in order to increase the thermal conductivity. At this time, by filling the semiconductor filler, the real part, which is a capacitance component of the complex permittivity of the radio wave absorber, and the imaginary part, which is a loss component, can be increased to approach the optimum value. By adding a conductive filler, an electrical path is connected between the semiconductor fillers, and by increasing the resistance at which electromagnetic waves propagate, the complex permittivity imaginary part, which is a loss component, is intentionally increased to optimize the radio wave. The absorption performance is improved. It is presumed to have the above mechanism of action.
≪製造≫
（実施例１）
原料には、媒体として粘度３５０ｃＰのシリコーンオイル、絶縁性熱伝導フィラーとして平均粒子径１８μｍのアルミナ粉末、半導体フィラーとして平均粒子径５０μｍ のSiC粉末、導電性フィラーとして長径９．７μｍ、短径が０．５μｍのATOコート針状酸化チタンを用いた。媒体となるシリコーンオイルに、その重量を100として、アルミナ粉末を269重量部、SiC粉末を187重量部、導電性フィラーを25重量部添加し、自公転ミキサーで混合・分散させて、実施例１の半固体状の電波吸収体を作製した。 ≪Manufacturing≫
(Example 1)
The raw materials are silicone oil with a viscosity of 350 cP as a medium, alumina powder with an average particle diameter of 18 μm as an insulating heat conductive filler, SiC powder with an average particle diameter of 50 μm as a semiconductor filler, major axis 9.7 μm as a conductive filler, and 0 minor axis. A 5.5 μm ATO-coated acicular titanium oxide was used. Example 1 is obtained by adding 269 parts by weight of alumina powder, 187 parts by weight of SiC powder, and 25 parts by weight of a conductive filler to silicone oil as a medium, and mixing and dispersing them with a rotation mixer. A semi-solid radio wave absorber was prepared.
（実施例１）
原料には、媒体として粘度３５０ｃＰのシリコーンオイル、絶縁性熱伝導フィラーとして平均粒子径１８μｍのアルミナ粉末、半導体フィラーとして平均粒子径５０μｍ のSiC粉末、導電性フィラーとして長径９．７μｍ、短径が０．５μｍのATOコート針状酸化チタンを用いた。媒体となるシリコーンオイルに、その重量を100として、アルミナ粉末を269重量部、SiC粉末を187重量部、導電性フィラーを25重量部添加し、自公転ミキサーで混合・分散させて、実施例１の半固体状の電波吸収体を作製した。 ≪Manufacturing≫
(Example 1)
The raw materials are silicone oil with a viscosity of 350 cP as a medium, alumina powder with an average particle diameter of 18 μm as an insulating heat conductive filler, SiC powder with an average particle diameter of 50 μm as a semiconductor filler, major axis 9.7 μm as a conductive filler, and 0 minor axis. A 5.5 μm ATO-coated acicular titanium oxide was used. Example 1 is obtained by adding 269 parts by weight of alumina powder, 187 parts by weight of SiC powder, and 25 parts by weight of a conductive filler to silicone oil as a medium, and mixing and dispersing them with a rotation mixer. A semi-solid radio wave absorber was prepared.
（実施例２～１８及び比較例１～３）
表１～表４に示す組成及び配合にて、実施例１に記載の製造方法に準じ、実施例２～１８及び比較例１～３に係る電波吸収材料を製造した。 (Examples 2 to 18 and Comparative Examples 1 to 3)
The radio wave absorbing materials according to Examples 2 to 18 and Comparative Examples 1 to 3 were produced according to the production method described in Example 1 with the compositions and formulations shown in Tables 1 to 4.
表１～表４に示す組成及び配合にて、実施例１に記載の製造方法に準じ、実施例２～１８及び比較例１～３に係る電波吸収材料を製造した。 (Examples 2 to 18 and Comparative Examples 1 to 3)
The radio wave absorbing materials according to Examples 2 to 18 and Comparative Examples 1 to 3 were produced according to the production method described in Example 1 with the compositions and formulations shown in Tables 1 to 4.
≪評価≫
表１～表４に、熱伝導性及び電磁波吸収性について評価した。 ≪Evaluation≫
Tables 1 to 4 evaluate the thermal conductivity and electromagnetic wave absorption.
表１～表４に、熱伝導性及び電磁波吸収性について評価した。 ≪Evaluation≫
Tables 1 to 4 evaluate the thermal conductivity and electromagnetic wave absorption.
Claims (7)
- 媒体と、
前記媒体に分散した半導体フィラーと、
前記媒体に分散した絶縁性熱伝導性フィラーと、
前記媒体に分散した導電性フィラーと
を有する電磁波吸収材料。 With the medium
The semiconductor filler dispersed in the medium and
Insulating thermal conductive filler dispersed in the medium,
An electromagnetic wave absorbing material having a conductive filler dispersed in the medium. - 前記電磁波吸収材料中に含まれる、前記媒体に対する前記半導体フィラーと前記絶縁性熱伝導性フィラーとの合計の体積比｛（前記半導体フィラー＋前記絶縁性熱伝導性フィラー）／前記媒体｝が１以上である、請求項１記載の電磁波吸収材料。 The total volume ratio of the semiconductor filler and the insulating heat conductive filler to the medium contained in the electromagnetic wave absorbing material {(the semiconductor filler + the insulating heat conductive filler) / the medium} is 1 or more. The electromagnetic wave absorbing material according to claim 1.
- 前記電磁波吸収材料中に含まれる、前記絶縁性熱伝導性フィラーに対する前記半導体フィラーの体積比（前記半導体フィラー／前記絶縁性熱伝導性フィラー）が０．７以上１．５以下である、請求項１又は２記載の電磁波吸収材料。 The claim that the volume ratio of the semiconductor filler to the insulating heat conductive filler (the semiconductor filler / the insulating heat conductive filler) contained in the electromagnetic wave absorbing material is 0.7 or more and 1.5 or less. The electromagnetic wave absorbing material according to 1 or 2.
- 前記電磁波吸収材料中に含まれる、前記半導体フィラーに対する前記導電性フィラーの体積比（前記導電性フィラー／前記半導体フィラー）が、０．０９以上０．２以下である、請求項１～３のいずれか一項記載の電磁波吸収材料。 Any of claims 1 to 3, wherein the volume ratio of the conductive filler to the semiconductor filler (the conductive filler / the semiconductor filler) contained in the electromagnetic wave absorbing material is 0.09 or more and 0.2 or less. The electromagnetic wave absorbing material described in item 1.
- 前記半導体フィラーが、ＳｉＣ及びＳｉから選択される１種以上である、請求項１～４のいずれか一項記載の電磁波吸収材料。 The electromagnetic wave absorbing material according to any one of claims 1 to 4, wherein the semiconductor filler is one or more selected from SiC and Si.
- 前記絶縁性熱伝導性フィラーが、Ａｌ２Ｏ３、ＭｇＯ、ＡｌＮ、ＢＮ及び金属炭酸塩から選択される１種以上である、請求項１～５のいずれか一項記載の電磁波吸収材料。 The electromagnetic wave absorbing material according to any one of claims 1 to 5, wherein the insulating heat conductive filler is at least one selected from Al 2 O 3, MgO, Al N, BN and a metal carbonate.
- 前記導電性フィラーが、カーボン及び酸化チタン（これらの表面にＩＴＯやＡＴＯを有するものを含む）から選択される１種以上である、請求項１～６のいずれか一項記載の電磁波吸収材料。
The electromagnetic wave absorbing material according to any one of claims 1 to 6, wherein the conductive filler is at least one selected from carbon and titanium oxide (including those having ITO or ATO on their surfaces).
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