JP7478374B2 - Electromagnetic wave shielding material and signal processing unit including same - Google Patents
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- 239000004734 Polyphenylene sulfide Substances 0.000 claims description 3
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- 239000004676 acrylonitrile butadiene styrene Substances 0.000 claims description 2
- 229920000122 acrylonitrile butadiene styrene Polymers 0.000 claims description 2
- 229920001643 poly(ether ketone) Polymers 0.000 claims description 2
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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
- C08K3/01—Use of inorganic substances as compounding ingredients characterized by their specific function
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- 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
- C08K3/02—Elements
- C08K3/04—Carbon
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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
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Description
本発明は、電磁波シールド材及びこれを備える信号処理ユニットに関し、特に、周辺環境からレーダーを保護するとともに、レーダーの信号伝達を阻害しないレーダーカバーに好適に用いることができる電磁波シールド材及びこれを備える信号処理ユニットに関する。なお、本明細書において「シールド」とは、吸収すなわち反射損失、遮蔽すなわち透過損失の少なくとも一方の意味で用いる。The present invention relates to an electromagnetic shielding material and a signal processing unit equipped with the same, and in particular to an electromagnetic shielding material suitable for use in a radar cover that protects a radar from the surrounding environment and does not impede radar signal transmission, and a signal processing unit equipped with the same. Note that in this specification, "shield" is used to mean at least one of absorption, i.e., reflection loss, and shielding, i.e., transmission loss.
特許文献１には、熱可塑性樹脂８５重量％から９５重量％ 、カーボンナノチューブ１重量％から５重量％及びカーボンブラック３重量％から１０重量％を含み、また前記カーボンナノチューブ及びカーボンブラックを３：７から１：７の重量比を含むことにより、優れた機械的物性とともにレーダー保護用として要求される電磁波の反射損失及び透過損失をバランス良く現わすレーダーカバー用熱可塑性樹脂組成物について開示されている。
ここで、特許文献１に開示されているレーダーカバー用熱可塑性樹脂組成物は、周辺環境からレーダーを十分に保護するとともに、レーダーの信号伝達を阻害しないようにするためには、電磁波の反射損失及び透過損失について、改善の余地があることがわかった。Here, it has been found that the thermoplastic resin composition for radar covers disclosed in Patent Document 1 has room for improvement in terms of electromagnetic wave reflection loss and transmission loss in order to adequately protect the radar from the surrounding environment while not impeding radar signal transmission.
具体的には、特許文献１に開示されているレーダーカバーは、２ｄＢから９ｄＢ範囲の電磁波の反射損失、及び、３ｄＢから１２ｄＢ範囲の電磁波の透過損失が得られる旨が記載されているが（００３６段落）、本発明者らの知見によれば、約６０ＧＨｚ～約１１０ＧＨｚの周波数帯域では、電磁波の反射損失と電磁波の透過損失との兼ね合いにもよるが、典型例を示すと、電磁波の反射損失は約５ｄＢ以上、電磁波の透過損失は約１５ｄＢ以上であることが必要である。Specifically, the radar cover disclosed in Patent Document 1 is described as being able to obtain an electromagnetic wave reflection loss in the range of 2 dB to 9 dB and an electromagnetic wave transmission loss in the range of 3 dB to 12 dB (paragraph 0036), but according to the inventors' findings, in the frequency band of approximately 60 GHz to approximately 110 GHz, typically the electromagnetic wave reflection loss needs to be approximately 5 dB or more and the electromagnetic wave transmission loss needs to be approximately 15 dB or more, although this depends on the balance between the electromagnetic wave reflection loss and the electromagnetic wave transmission loss.
なお、本発明者らの知見に基づき、上記のような条件の数値が必要であるという根拠は、以下のとおりである。すなわち、電磁波の透過損失に着目すると、電磁波の透過損失が例えば２０ｄＢであれば、電磁波の遮蔽率は９０％であるから、電磁波シールド材の第１面から入射した電磁波は、電磁波シールド材の第２面から出射する際には９０％が減衰され１０％となる。Based on the findings of the inventors, the reasons why the numerical values of the above conditions are necessary are as follows: In other words, when focusing on the transmission loss of electromagnetic waves, if the transmission loss of electromagnetic waves is, for example, 20 dB, the electromagnetic wave shielding rate is 90%, so that the electromagnetic waves incident on the first surface of the electromagnetic shielding material are attenuated by 90% to 10% when they are emitted from the second surface of the electromagnetic shielding material.
そして、残った電磁波が何らかの部材に衝突し、そこで反射されて、再び、第２面を通じて電磁波シールド材に入射すると、電磁波シールド材の第１面から出射する際には、その９０％が減衰され１０％となる。したがって、この例では、当初の電磁波に対して９９％が減衰することになる。 If the remaining electromagnetic waves collide with some other component, are reflected there, and then enter the electromagnetic shielding material again through the second surface, 90% of the waves will be attenuated to 10% when they leave the first surface of the electromagnetic shielding material. Therefore, in this example, the initial electromagnetic waves will be attenuated by 99%.
このように考えてみると、透過損失が優れていれば、反射損失については５ｄＢ程度あれば十分ということができる。さらに、信頼性の高い電磁波シールド材を提供しようとするならば、電磁波シールド材の製造誤差などを原因として発生する個体差であったり、電磁波シールド材の使用環境であったりなどを考慮して、電磁波シールド材のユーザに対する品質保証の観点から、更に幾分かの電磁波の遮蔽をすればよいといえる。Considering this, if the transmission loss is excellent, a reflection loss of about 5 dB can be said to be sufficient. Furthermore, if one wishes to provide a highly reliable electromagnetic shielding material, it would be sufficient to provide some more electromagnetic shielding from the perspective of quality assurance for users of the electromagnetic shielding material, taking into consideration individual differences caused by manufacturing errors in the electromagnetic shielding material and the environment in which the electromagnetic shielding material is used.
そうすると、電磁波シールド材を設置する個所の近傍に、金属などのように電磁波の遮蔽機能がある他のものが存在している場合には、反射損失が約６ｄＢもあれば十分であろうと考えられ、また、電磁波の遮蔽機能がある他のものが存在していない場合であっても、反射損失が約７ｄＢもあれば十分であろうと考えられる。 Therefore, if there is something else with electromagnetic wave shielding function, such as metal, near the location where the electromagnetic shielding material is to be installed, a reflection loss of approximately 6 dB would be sufficient, and even if there is no other thing with electromagnetic wave shielding function present, a reflection loss of approximately 7 dB would be sufficient.
一方、電磁波の反射損失に着目してみると、電磁波の反射損失が５ｄＢであれば、電磁波の吸収率は５０％であり、更に透過損失が２０ｄＢであれば、吸収率は９０％であるから、１００という電磁波のうち５０％が反射されるとともに、残りの５０％の電磁波のうち９０％が遮蔽されるので、結果的には電磁波シールド材の出射面から出射される電磁波は５％まで低減されるとも考えられる。On the other hand, if we look at the reflection loss of electromagnetic waves, if the reflection loss of electromagnetic waves is 5 dB, the absorption rate of electromagnetic waves is 50%, and if the transmission loss is 20 dB, the absorption rate is 90%, so 50% of 100 electromagnetic waves is reflected and 90% of the remaining 50% electromagnetic waves is shielded, so that the electromagnetic waves emitted from the exit surface of the electromagnetic wave shielding material are reduced to 5%.
したがって、電磁波の反射損失は約５ｄＢ以上、電磁波の透過損失は約１５ｄＢ以上であることが必要であるということがいえるのである。 Therefore, it can be said that the reflection loss of electromagnetic waves must be approximately 5 dB or more, and the transmission loss of electromagnetic waves must be approximately 15 dB or more.
なお、ここでは電磁波の透過損失が２０ｄＢであることを前提に説明したが、これが仮に１５ｄＢとなっても、電磁波の遮蔽率は約８２％であるので、反射損失が５ｄＢであれば、残り約１８％の電磁波は約９％まで低減できるし、必要であれば、反射損失が例えば６ｄＢという条件の電磁波シールド材を用いればよいということになる。 Note that the explanation here is based on the assumption that the electromagnetic wave transmission loss is 20 dB, but even if this is reduced to 15 dB, the electromagnetic wave shielding rate is approximately 82%, so if the reflection loss is 5 dB, the remaining approximately 18% of electromagnetic waves can be reduced to approximately 9%, and if necessary, an electromagnetic wave shielding material with a reflection loss of, for example, 6 dB can be used.
以上の考察から、本発明は、少なくとも９０％以上の遮蔽性能が得られる電磁波シールド材を提供することを課題とする。 Based on the above considerations, the objective of the present invention is to provide an electromagnetic wave shielding material that can achieve shielding performance of at least 90%.
上記課題を解決するために、本発明の電磁波シールド材及びこれを備える信号処理ユニットは、
主成分となる樹脂と、
電磁波の反射損失が５０％以上になる分量で前記樹脂に含有される電磁波遮蔽物質１と、
電磁波の透過損失が８０％以上になる分量で前記樹脂に含有される電磁波遮蔽物質２と、
を含む。
In order to solve the above problems, the electromagnetic shielding material and the signal processing unit including the same according to the present invention are
The main component is resin,
an electromagnetic wave shielding material 1 contained in the resin in an amount such that the reflection loss of electromagnetic waves is 50% or more;
an electromagnetic
including.
前記樹脂は熱可塑性樹脂とすることができ、前記各電磁波遮蔽物質はナノカーボンとすることができる。 The resin may be a thermoplastic resin, and each of the electromagnetic wave shielding materials may be nanocarbon.
より詳しく一例をあげると、前記樹脂は、ポリオレフィン、ポリフェニレンサルファイド、ポリアミド、ポリカーボネート、ポリブチレン、ポリエーテルイミドなどのいずれか又はこれらのうちいくつかを任意に組合せることができる。前記各電磁波遮蔽物質は、カーボンナノチューブ、カーボンブラック、カーボンナノコイル、カーボンナノファイバー、グラフェン、フラーレンなどのうち、電磁波の反射損失の上昇に寄与する電磁波遮蔽物質１と、電磁波の透過損失の上昇に寄与する電磁波遮蔽物質２とを、任意に組合せることができる。いくつかを任意に組合せることができる。
More specifically, the resin may be any one of polyolefin, polyphenylene sulfide, polyamide, polycarbonate, polybutylene, polyetherimide, etc., or any combination of several of these. The electromagnetic wave shielding materials may be any combination of an electromagnetic wave shielding material 1 that contributes to an increase in the reflection loss of electromagnetic waves and an electromagnetic
また、前記各電磁波遮蔽物質を前記樹脂に対して分散させる分散剤を含んでもよい。前記分散剤は天然・半合成・合成ワックスのいずれかとすることができる。より詳しく一例をあげると、前記分散剤は、パラフィンワックス、モンタンワックス、アマイドワックス、エチレン－ビス－ステアラミド、脂肪酸金属塩、シリコーン、ポリオレフィンワックスなどのいずれか又はこれらのうちいくつかを任意に組合せることができる。 The resin may also contain a dispersant that disperses the electromagnetic wave shielding materials in the resin. The dispersant may be any of natural, semi-synthetic, and synthetic waxes. In more detail, the dispersant may be any of paraffin wax, montan wax, amide wax, ethylene-bis-stearamide, fatty acid metal salts, silicone, polyolefin wax, etc., or any combination of these.
なお、本発明の電磁波シールド材の製造工程は限定的でなく、例えば、プレス加工を採用してもよいし、射出加工を採用してもよい。なお、プレス加工を採用した場合には、電磁波シールド材の表面抵抗率は、概ね、２５０Ω／□～７５０Ω／□であり、電磁波シールド材の厚さが２ｍｍ～６ｍｍという条件においては、３００Ω／□～５００Ω／□程度のものが好適な遮蔽性能を有することが分かった。The manufacturing process of the electromagnetic shielding material of the present invention is not limited, and may be, for example, press processing or injection processing. When press processing is used, the surface resistivity of the electromagnetic shielding material is generally 250 Ω/□ to 750 Ω/□, and it has been found that a surface resistivity of about 300 Ω/□ to 500 Ω/□ has suitable shielding performance when the thickness of the electromagnetic shielding material is 2 mm to 6 mm.
また、本発明の信号処理ユニットは、電磁波シールド材を有する自動車用近接レーダー、携帯電話機・スマートフォン・ＰＤＡ・タブレット端末・パーソナルコンピュータを含む通信機器、各種近接レーダーとすることができる。 In addition, the signal processing unit of the present invention can be used as an automotive proximity radar having electromagnetic shielding material, communication devices including mobile phones, smartphones, PDAs, tablet terminals, and personal computers, and various proximity radars.
以下、本発明の実施形態について図表を用いて説明する。 Below, an embodiment of the present invention is explained using diagrams and charts.
本実施形態の電磁波シールド材は、
（１）主成分となる樹脂と、
（２）樹脂に含有される電磁波遮蔽物質と、
を含むことが必須である。
さらに、選択的に、樹脂に対して電磁波遮蔽物質を分散させる分散剤を含めることもできる。なお、本実施形態の電磁波シールド材自体は、金属物質を含有していない。
The electromagnetic wave shielding material of this embodiment is
(1) a resin as a main component;
(2) an electromagnetic wave shielding material contained in the resin;
It is essential to include
Furthermore, a dispersant for dispersing the electromagnetic shielding material in the resin may be optionally included. Note that the electromagnetic shielding material of this embodiment itself does not contain any metal material.
本実施形態の電磁波シールド材は、反射損失は約６ｄＢ以上とし、透過損失は約１５ｄＢ以上の性能とすることで、たとえ、電磁波シールド材の製造誤差、個体差などがあっても、製造品のほぼ全てが総合的に見た場合に、電磁波の９０％程度の遮蔽を実現できるようにしている。なお、このような性能となる電磁波遮蔽体をプレス加工によって製造する場合には、表面抵抗率が約３００Ω／□～約５００Ω／□となることがわかった。もっとも、プレス加工に代えて、射出加工などの他の加工を採用することもできる。この場合には、表面抵抗率には大きな変化があろうが、体積抵抗率・導電率には理論上変化はない。 The electromagnetic shielding material of this embodiment has a reflection loss of about 6 dB or more and a transmission loss of about 15 dB or more, so that even if there are manufacturing errors or individual differences in the electromagnetic shielding material, almost all manufactured products can achieve approximately 90% shielding of electromagnetic waves when viewed overall. It has been found that when an electromagnetic shielding body with such performance is manufactured by press processing, the surface resistivity is about 300 Ω/□ to about 500 Ω/□. However, other processes such as injection processing can be used instead of press processing. In this case, there will be a large change in the surface resistivity, but theoretically there will be no change in the volume resistivity and conductivity.
なお、本実施形態の電磁波シールド材と特許文献１に開示されているレーダーカバー用熱可塑性樹脂組成物との相違点を明らかにするために、特許文献１に開示されている性能について付言すると、実施例１～３のものとしては、それぞれ、反射損失は、６ｄＢ、５ｄＢ、３ｄＢであり、透過損失は、３ｄＢ、３ｄＢ、５ｄＢ以上である、とされている。In addition, in order to clarify the differences between the electromagnetic wave shielding material of this embodiment and the thermoplastic resin composition for radar covers disclosed in Patent Document 1, the performance disclosed in Patent Document 1 will be described in addition, with respect to Examples 1 to 3, the reflection losses are 6 dB, 5 dB, and 3 dB, and the transmission losses are 3 dB, 3 dB, and 5 dB or more, respectively.
両者を対比すると、実施例１の反射損失こそ６ｄＢが得られているものの、その透過損失は３ｄＢしかなく、実施例２，３のものは反射損失についても透過損失についても本実施形態のものに比して良い性能が得られていない。いずれにしても、特許文献１に開示されているレーダーカバー用熱可塑性樹脂組成物は、本実施形態の電磁波シールド材とは、その遮蔽特性が大きく異なることがわかる。Comparing the two, while Example 1 achieved a reflection loss of 6 dB, its transmission loss was only 3 dB, and Examples 2 and 3 did not achieve better performance in terms of reflection loss or transmission loss than the present embodiment. In any case, it can be seen that the thermoplastic resin composition for radar covers disclosed in Patent Document 1 has significantly different shielding properties from the electromagnetic wave shielding material of the present embodiment.
また、樹脂は熱可塑性樹脂とすることができ、より詳しく一例をあげると、ポリオレフィン、ポリフェニレンスルファイド、ポリアミド、ポリイミド、ポリアミドイミド、ポリカーボネート、ポリアセタール、ポリエーテルスルホン、ポリブチレン、ポリエーテルイミド、ポリエーテルケトン、ポリエーテルイミド、ポリアルキレンテレフタレート、ポリスルホン、ポリスチレン、シンジオタクチックポリスチレン、アクリロニトリルブタジエンスチレン、ポリフェニレンオキシド、アクリル系樹脂、液晶重合体樹脂などのいずれか又はこれらのうちいくつかを任意に組合せることができる。The resin may be a thermoplastic resin, and more specifically, examples of the resin may include polyolefin, polyphenylene sulfide, polyamide, polyimide, polyamideimide, polycarbonate, polyacetal, polyethersulfone, polybutylene, polyetherimide, polyetherketone, polyetherimide, polyalkylene terephthalate, polysulfone, polystyrene, syndiotactic polystyrene, acrylonitrile butadiene styrene, polyphenylene oxide, acrylic resins, liquid crystal polymer resins, etc., or any combination of these.
さらに、電磁波遮蔽物質は、電磁波の反射損失と透過損失との上昇に寄与する、一種類又は数種類のナノカーボンとすることができる。典型的には、カーボンナノチューブ、カーボンブラック、カーボンナノコイル、カーボンナノファイバー、グラフェン、フラーレンなどのうち、電磁波の反射損失の上昇に寄与するものと、電磁波の透過損失の上昇に寄与するものとを、任意に組合せることができるが、単一のナノカーボンを選択することもできる。 Furthermore, the electromagnetic wave shielding material may be one or several kinds of nanocarbons that contribute to increasing the reflection loss and transmission loss of electromagnetic waves. Typically, among carbon nanotubes, carbon black, carbon nanocoils, carbon nanofibers, graphene, fullerene, etc., those that contribute to increasing the reflection loss of electromagnetic waves and those that contribute to increasing the transmission loss of electromagnetic waves may be arbitrarily combined, but a single nanocarbon may also be selected.
このうち、電磁波の反射損失の上昇に寄与するものとしてはカーボンナノチューブ、電磁波の透過損失の上昇に寄与するものとしてはカーボンブラックが、市場での入手容易なものとして挙げられる。カーボンナノチューブについては、０．５ｎｍ～２０ｎｍの平均内径を有するものとすることができる。カーボンブラックについては、二次平均粒径が１０μｍ～２００μｍのものとすることができる。 Among these, carbon nanotubes contribute to an increase in the reflection loss of electromagnetic waves, and carbon black contributes to an increase in the transmission loss of electromagnetic waves, and are easily available on the market. Carbon nanotubes can have an average inner diameter of 0.5 nm to 20 nm. Carbon black can have an average secondary particle diameter of 10 μm to 200 μm.
さらにまた、選択的に電磁波シールド材に含めることが可能な分散剤は、天然・半合成・合成ワックスのいずれかとすることができ、パラフィンワックス、モンタンワックス、アマイドワックス、エチレン－ビス－ステアラミド、脂肪酸金属塩、シリコーン、ポリオレフィンワックスなどのいずれか又はこれらのうちいくつかを任意に組合せることができる。Furthermore, the dispersant that can be selectively included in the electromagnetic shielding material can be any of natural, semi-synthetic, or synthetic waxes, and can be any of paraffin wax, montan wax, amide wax, ethylene-bis-stearamide, fatty acid metal salts, silicone, polyolefin wax, etc., or any combination of several of these.
樹脂と電磁波遮蔽物質との混合割合は、樹脂としてポリプロピレン、電磁波遮蔽物質１としてカーボンナノチューブ、電磁波遮蔽物質２としてカーボンブラックを用いた場合には、［樹脂：電磁波遮蔽物質１：電磁波遮蔽物質２＝約９０重量％：約０．１重量％～約１重量％：約１０重量］とすることができ、分散剤を用いる場合には、樹脂の分量を５％～４０％程度減らして、その代わりに、分散剤を混合すればよい。The mixing ratio of resin and electromagnetic shielding material, when using polypropylene as the resin, carbon nanotubes as electromagnetic shielding material 1, and carbon black as
もっとも、本発明者らの考察によれば、分散剤としては、市場流通性・価格などに着目すると、ポリエチレンワックスが選択しやすく、ポリエチレンワックス又はこれに類する分散剤を選択する場合には、樹脂等として選択する材料にもよるが、樹脂の分量を５％～２０％程度減らして、その代わりに、ポリエチレンワックス等を混合すればよい。However, according to the inventors' considerations, polyethylene wax is an easy choice as a dispersant when market availability and price are taken into consideration. When polyethylene wax or a similar dispersant is selected, the amount of resin can be reduced by about 5% to 20%, depending on the material selected as the resin, etc., and polyethylene wax, etc. can be mixed in instead.
なお、特許文献１に開示されているレーダーカバー用熱可塑性樹脂組成物について付言すると、特許文献１には分散剤について考察及び言及がなされていないので、この点は明らかではないが、［熱可塑性樹脂：カーボンナノチューブ：カーボンブラック＝８５重量％～９５重量％：１重量％～５重量％：３重量％～１０重量％］であり、かつ、［カーボンナノチューブ：カーボンブラック＝３：７～１：７］の重量比である。 In addition, with regard to the thermoplastic resin composition for radar covers disclosed in Patent Document 1, there is no discussion or mention of dispersants in Patent Document 1, so this point is not clear, but the composition is [thermoplastic resin: carbon nanotubes: carbon black = 85% by weight to 95% by weight: 1% by weight to 5% by weight: 3% by weight to 10% by weight] and the weight ratio is [carbon nanotubes: carbon black = 3:7 to 1:7].
したがって、本実施形態の電磁波遮材は、カーボンナノチューブの組成割合が相対的に少ないという点で、特許文献１に開示されているレーダーカバー用熱可塑性樹脂組成物とは異なる。そして、一般的に、電磁波遮材を構成するもののうち、カーボンナノチューブは高価であることから、相対的にカーボンナノチューブの混合量を少なくできるということは、本実施形態の電磁波遮材は、安価に実現できるということになる。Therefore, the electromagnetic wave shielding material of this embodiment differs from the thermoplastic resin composition for radar covers disclosed in Patent Document 1 in that the composition ratio of carbon nanotubes is relatively small. And since carbon nanotubes are generally expensive among the components that make up an electromagnetic wave shielding material, being able to relatively reduce the amount of carbon nanotubes mixed means that the electromagnetic wave shielding material of this embodiment can be realized at low cost.
以下、本発明の実施例の電磁波シールド材について、樹脂としてポリプロピレンを主成分としたもの、電磁波遮蔽物質１としてカーボンナノチューブ、電磁波遮蔽物質２としてカーボンブラックを用いて行った場合を例に説明する。また、実施例１～実施例４では、電磁波シールド材の厚さを約２ｍｍとし、実施例５～実施例９では、電磁波シールド材の厚さを約６ｍｍとした。
Below, the electromagnetic shielding material of the embodiment of the present invention will be described using as an example a resin mainly composed of polypropylene, carbon nanotubes as electromagnetic shielding material 1, and carbon black as
このような厚さとした理由は、厚さが２ｍｍのものについては、例えばＡＤＡＳのレーダーのように、電磁波シールド材を設置する個所の近傍に、金属などのように電磁波の遮蔽機能がある他のものが存在していて、かつ、電磁波シールド材の設置スペースが相対的に小さい場合に好適に用いることができる条件を想定しただけである。The reason for setting this thickness is that a thickness of 2 mm is assumed to be suitable for use in cases where there is something else with electromagnetic wave shielding function, such as metal, near the location where the electromagnetic shielding material is to be installed, such as an ADAS radar, and the installation space for the electromagnetic shielding material is relatively small.
また、厚さが６ｍｍのものについては、例えばＡＤＡＳのレーダーと当該レーダーを自動車に取り付けるために取付部とが一体となったレーダユニットのように、電磁波シールド材を設置する個所の近傍に、金属などのように電磁波の遮蔽機能がある他のものが存在しているが存在していて、かつ、電磁波シールド材の設置スペースが相対的に大きい場合に好適に用いることができる条件を想定しただけである。 In addition, with regard to the 6 mm thickness, we have only assumed conditions under which the electromagnetic shielding material can be suitably used when there is another object with electromagnetic wave shielding function, such as metal, near the location where the electromagnetic shielding material is to be installed, such as a radar unit in which an ADAS radar is integrated with a mounting portion for attaching the radar to an automobile, and the installation space for the electromagnetic shielding material is relatively large.
なお、レーダーでは、そのアンテナから放射されるバックローブが、その電子制御ユニット（ＥＣＵ）に到達することを回避するために、電磁波シールド材を用いることが考えられる。そうすると、これに限定されるものではないが、一例をあげると、電磁波シールド材を電子制御ユニット自体に貼付することが考えられる。In addition, in order to prevent the back lobe emitted from the radar antenna from reaching the electronic control unit (ECU), it is possible to use an electromagnetic shielding material. One example, but not limited to this, is to attach the electromagnetic shielding material to the electronic control unit itself.
また、レーダユニットでは、その取付部に貼付する、又は、この一部或いは全部の材料とすることが考えられる。さらに、レーダーがホーン型アンテナを備える場合には、当該アンテナの外側に貼付することも考えられる。In addition, in the case of a radar unit, it is conceivable that the label may be attached to the mounting portion, or may be used as a part or all of the material of the mounting portion. Furthermore, if the radar is equipped with a horn-type antenna, it is conceivable that the label may be attached to the outside of the antenna.
ここで、上記のように、電磁波シールド材の厚さを２ｍｍ、６ｍｍとすることは、技術的観点からすると、それほど意味を持たないので、これらの厚さに限定されるものではない点には留意されたい。したがって、電磁波シールド材の用途及び設置環境に応じて要求される遮蔽性能を満たすものを、実施例１～実施例９の中から適宜選択して、信号処理ユニットに備えればよい。It should be noted that, as stated above, setting the thickness of the electromagnetic shielding material to 2 mm or 6 mm does not mean much from a technical point of view, and therefore the thickness is not limited to these thicknesses. Therefore, it is sufficient to select from Examples 1 to 9 an electromagnetic shielding material that satisfies the shielding performance required depending on the application and installation environment of the material, and provide it in the signal processing unit.
もっとも、実施例１～実施例９に示す製造条件は例示的であり、例えば、カーボンナノチューブの混合量が実施例１よりは少ないが、実施例２よりも多い条件で製造された電磁波シールド材が、信号処理ユニットへ採用できることが除外されるわけではない点についても留意されたい。 However, it should be noted that the manufacturing conditions shown in Examples 1 to 9 are illustrative, and it is not excluded that an electromagnetic shielding material manufactured under conditions in which the amount of carbon nanotubes mixed is less than that in Example 1 but more than that in Example 2 can be used in a signal processing unit.
（実施例１）
樹脂：約８８．８０ｗｔ％
電磁波遮蔽物質１：約１．２００ｗｔ％
電磁波遮蔽物質２：約１０．００ｗｔ％
を混合し、これらが均一に分散するように二軸押出機を用いることによって適宜撹拌させ、プレス加工をするなど既知の手法によって、約２ｍｍの厚さの電磁波シールド材を製造した。
Example 1
Resin: Approximately 88.80 wt%
Electromagnetic wave shielding material 1: about 1.200 wt%
Electromagnetic wave shielding material 2: about 10.00 wt%
The mixture was mixed and appropriately stirred using a twin-screw extruder so as to disperse the mixture uniformly, and then pressed into an electromagnetic shielding material having a thickness of about 2 mm by a known method.
なお、実施例１の電磁波シールド材について、導電率及び表面抵抗率を測定してみたところ、導電率は約２．００Ｓ／ｍであり、表面抵抗率は約２５０Ω／□であった。When the electrical conductivity and surface resistivity of the electromagnetic shielding material of Example 1 were measured, the electrical conductivity was approximately 2.00 S/m and the surface resistivity was approximately 250 Ω/□.
図１は、実施例１の電磁波シールド材の透過損失を示す図である。図１の横軸には周波数［ＧＨｚ］を示し、図１の縦軸には透過損失［ｄＢ］を示している。図１に示すように、実施例１の電磁波シールド材は、７５ＧＨｚ～１１０ＧＨｚの周波数帯域全体に亘り、透過損失が２０ｄＢ以上であることがわかる。 Figure 1 is a diagram showing the transmission loss of the electromagnetic shielding material of Example 1. The horizontal axis of Figure 1 shows frequency [GHz], and the vertical axis of Figure 1 shows transmission loss [dB]. As shown in Figure 1, it can be seen that the electromagnetic shielding material of Example 1 has a transmission loss of 20 dB or more over the entire frequency band from 75 GHz to 110 GHz.
図２は、実施例１の電磁波シールド材の反射損失を示す図である。図２の横軸には周波数［ＧＨｚ］を示し、図２の縦軸には反射損失［ｄＢ］を示している。図２に示すように、実施例１の電磁波シールド材は、７５ＧＨｚ～１１０ＧＨｚの周波数帯域全体に亘り、反射損失が６ｄＢ以上であることがわかる。 Figure 2 is a diagram showing the reflection loss of the electromagnetic shielding material of Example 1. The horizontal axis of Figure 2 shows frequency [GHz], and the vertical axis of Figure 2 shows reflection loss [dB]. As shown in Figure 2, it can be seen that the electromagnetic shielding material of Example 1 has a reflection loss of 6 dB or more over the entire frequency band from 75 GHz to 110 GHz.
（実施例２）
樹脂：約８９．３０ｗｔ％
電磁波遮蔽物質１：約０．７００ｗｔ％
電磁波遮蔽物質２：約１０．００ｗｔ％
を混合し、これらが均一に分散するように二軸押出機を用いることによって適宜撹拌させ、プレス加工をするなど既知の手法によって、約２ｍｍの厚さの電磁波シールド材を製造した。
Example 2
Resin: Approximately 89.30 wt%
Electromagnetic wave shielding material 1: about 0.700 wt%
Electromagnetic wave shielding material 2: about 10.00 wt%
The mixture was mixed and appropriately stirred using a twin-screw extruder so as to disperse the mixture uniformly, and then pressed into an electromagnetic shielding material having a thickness of about 2 mm by a known method.
なお、実施例２の電磁波シールド材について、導電率及び表面抵抗率を測定してみたところ、導電率は約１．６７Ｓ／ｍであり、表面抵抗率は約３００Ω／□であった。When the electrical conductivity and surface resistivity of the electromagnetic shielding material of Example 2 were measured, the electrical conductivity was approximately 1.67 S/m and the surface resistivity was approximately 300 Ω/□.
図３は、実施例２の電磁波シールド材の透過損失を示す図である。図３の横軸には周波数［ＧＨｚ］を示し、図３の縦軸には透過損失［ｄＢ］を示している。図３に示すように、実施例２の電磁波シールド材は、７５ＧＨｚ～１１０ＧＨｚの周波数帯域全体に亘り、透過損失が２０ｄＢ以上であることがわかる。 Figure 3 is a diagram showing the transmission loss of the electromagnetic shielding material of Example 2. The horizontal axis of Figure 3 shows frequency [GHz], and the vertical axis of Figure 3 shows transmission loss [dB]. As shown in Figure 3, it can be seen that the electromagnetic shielding material of Example 2 has a transmission loss of 20 dB or more over the entire frequency band from 75 GHz to 110 GHz.
図４は、実施例２の電磁波シールド材の反射損失を示す図である。図４の横軸には周波数［ＧＨｚ］を示し、図４の縦軸には反射損失［ｄＢ］を示している。図４に示すように、実施例２の電磁波シールド材は、６０ＧＨｚ～９０ＧＨｚの周波数帯域全体に亘り、反射損失が６ｄＢ以上であることがわかる。 Figure 4 is a diagram showing the reflection loss of the electromagnetic shielding material of Example 2. The horizontal axis of Figure 4 shows frequency [GHz], and the vertical axis of Figure 4 shows reflection loss [dB]. As shown in Figure 4, it can be seen that the electromagnetic shielding material of Example 2 has a reflection loss of 6 dB or more over the entire frequency band from 60 GHz to 90 GHz.
（実施例３）
樹脂：約８９．４０ｗｔ％
電磁波遮蔽物質１：約０．６００ｗｔ％
電磁波遮蔽物質２：約１０．００ｗｔ％
を混合し、これらが均一に分散するように二軸押出機を用いることによって適宜撹拌させ、プレス加工をするなど既知の手法によって、約２ｍｍの厚さの電磁波シールド材を製造した。
Example 3
Resin: Approximately 89.40 wt%
Electromagnetic wave shielding material 1: about 0.600 wt%
Electromagnetic wave shielding material 2: about 10.00 wt%
The mixture was mixed and appropriately stirred using a twin-screw extruder so as to disperse the mixture uniformly, and then pressed into an electromagnetic shielding material having a thickness of about 2 mm by a known method.
なお、実施例３の電磁波シールド材について、導電率及び表面抵抗率を測定してみたところ、導電率は約１．２５Ｓ／ｍであり、表面抵抗率は約４００Ω／□であった。When the electrical conductivity and surface resistivity of the electromagnetic shielding material of Example 3 were measured, the electrical conductivity was approximately 1.25 S/m and the surface resistivity was approximately 400 Ω/□.
図５は、実施例３の電磁波シールド材の透過損失を示す図である。図５の横軸には周波数［ＧＨｚ］を示し、図５の縦軸には透過損失［ｄＢ］を示している。図５に示すように、実施例３の電磁波シールド材は、７５ＧＨｚ～１１０ＧＨｚの周波数帯域全体に亘り、透過損失がほぼ２０ｄＢ以上であることがわかる。 Figure 5 is a diagram showing the transmission loss of the electromagnetic shielding material of Example 3. The horizontal axis of Figure 5 shows frequency [GHz], and the vertical axis of Figure 5 shows transmission loss [dB]. As shown in Figure 5, it can be seen that the electromagnetic shielding material of Example 3 has a transmission loss of approximately 20 dB or more over the entire frequency band from 75 GHz to 110 GHz.
図６は、実施例３の電磁波シールド材の反射損失を示す図である。図６の横軸には周波数［ＧＨｚ］を示し、図６の縦軸には反射損失［ｄＢ］を示している。図６に示すように、実施例３の電磁波シールド材は、６０ＧＨｚ～９０ＧＨｚの周波数帯域全体に亘り、反射損失が６ｄＢ以上であることがわかる。 Figure 6 is a diagram showing the reflection loss of the electromagnetic shielding material of Example 3. The horizontal axis of Figure 6 shows frequency [GHz], and the vertical axis of Figure 6 shows reflection loss [dB]. As shown in Figure 6, it can be seen that the electromagnetic shielding material of Example 3 has a reflection loss of 6 dB or more over the entire frequency band from 60 GHz to 90 GHz.
（実施例４）
樹脂：約８９．３７ｗｔ％
電磁波遮蔽物質１：約０．６３０ｗｔ％
電磁波遮蔽物質２：約１０．００ｗｔ％
を混合し、これらが均一に分散するように二軸押出機を用いることによって適宜撹拌させ、プレス加工をするなど既知の手法によって、約２ｍｍの厚さの電磁波シールド材を製造した。
Example 4
Resin: about 89.37 wt%
Electromagnetic wave shielding material 1: about 0.630 wt%
Electromagnetic wave shielding material 2: about 10.00 wt%
The mixture was mixed and appropriately stirred using a twin-screw extruder so as to disperse the mixture uniformly, and then pressed into an electromagnetic shielding material having a thickness of about 2 mm by a known method.
なお、実施例４の電磁波シールド材について、導電率及び表面抵抗率を測定してみたところ、導電率は約１．００Ｓ／ｍであり、表面抵抗率は約５００Ω／□であった。When the electrical conductivity and surface resistivity of the electromagnetic shielding material of Example 4 were measured, the electrical conductivity was approximately 1.00 S/m and the surface resistivity was approximately 500 Ω/□.
図７は、実施例４の電磁波シールド材の透過損失を示す図である。図７の横軸には周波数［ＧＨｚ］を示し、図７の縦軸には透過損失［ｄＢ］を示している。図７に示すように、実施例４の電磁波シールド材は、７５ＧＨｚ～１１０ＧＨｚの周波数帯域全体に亘り、透過損失が１５ｄＢ以上であることがわかる。 Figure 7 is a diagram showing the transmission loss of the electromagnetic shielding material of Example 4. The horizontal axis of Figure 7 shows frequency [GHz], and the vertical axis of Figure 7 shows transmission loss [dB]. As shown in Figure 7, it can be seen that the electromagnetic shielding material of Example 4 has a transmission loss of 15 dB or more over the entire frequency band from 75 GHz to 110 GHz.
図８は、実施例４の電磁波シールド材の反射損失を示す図である。図８の横軸には周波数［ＧＨｚ］を示し、図８の縦軸には反射損失［ｄＢ］を示している。図８に示すように、実施例４の電磁波シールド材は、７５ＧＨｚ～１１０ＧＨｚの周波数帯域全体に亘り、反射損失が６ｄＢ以上であることがわかる。 Figure 8 is a diagram showing the reflection loss of the electromagnetic shielding material of Example 4. The horizontal axis of Figure 8 shows frequency [GHz], and the vertical axis of Figure 8 shows reflection loss [dB]. As shown in Figure 8, it can be seen that the electromagnetic shielding material of Example 4 has a reflection loss of 6 dB or more over the entire frequency band from 75 GHz to 110 GHz.
（実施例５）
樹脂：約８９．７３ｗｔ％
電磁波遮蔽物質１：約０．２７０ｗｔ％
電磁波遮蔽物質２：約１０．００ｗｔ％
を混合し、これらが均一に分散するように二軸押出機を用いることによって適宜撹拌させ、プレス加工をするなど既知の手法によって、約６ｍｍの厚さの電磁波シールド材を製造した。
Example 5
Resin: about 89.73 wt%
Electromagnetic wave shielding material 1: about 0.270 wt%
Electromagnetic wave shielding material 2: about 10.00 wt%
The mixture was mixed and appropriately stirred using a twin-screw extruder so as to disperse the mixture uniformly, and then pressed into an electromagnetic shielding material having a thickness of about 6 mm by a known method.
なお、実施例５の電磁波シールド材について、導電率及び表面抵抗率を測定してみたところ、導電率は約０．６７Ｓ／ｍであり、表面抵抗率は約２５０Ω／□であった。When the electrical conductivity and surface resistivity of the electromagnetic shielding material of Example 5 were measured, the electrical conductivity was approximately 0.67 S/m and the surface resistivity was approximately 250 Ω/□.
図９は、実施例５の電磁波シールド材の透過損失を示す図である。図９の横軸には周波数［ＧＨｚ］を示し、図９の縦軸には透過損失［ｄＢ］を示している。図９に示すように、実施例５の電磁波シールド材は、７５ＧＨｚ～１１０ＧＨｚの周波数帯域全体に亘り、透過損失が３０ｄＢ以上であり、とりわけ、約９０ＧＨｚ～１１０ＧＨｚの周波数帯域全体では、遮蔽性能が４０ｄＢ以上であることがわかる。 Figure 9 is a diagram showing the transmission loss of the electromagnetic shielding material of Example 5. The horizontal axis of Figure 9 shows frequency [GHz], and the vertical axis of Figure 9 shows transmission loss [dB]. As shown in Figure 9, the electromagnetic shielding material of Example 5 has a transmission loss of 30 dB or more over the entire frequency band of 75 GHz to 110 GHz, and in particular, it can be seen that the shielding performance is 40 dB or more over the entire frequency band of approximately 90 GHz to 110 GHz.
図１０は、実施例５の電磁波シールド材の反射損失を示す図である。図１０の横軸には周波数［ＧＨｚ］を示し、図１０の縦軸には反射損失［ｄＢ］を示している。図１０に示すように、実施例５の電磁波シールド材は、７５ＧＨｚ～１１０ＧＨｚの周波数帯域全体に亘り、反射損失が８ｄＢ以上であることがわかる。 Figure 10 is a diagram showing the reflection loss of the electromagnetic shielding material of Example 5. The horizontal axis of Figure 10 shows frequency [GHz], and the vertical axis of Figure 10 shows reflection loss [dB]. As shown in Figure 10, it can be seen that the electromagnetic shielding material of Example 5 has a reflection loss of 8 dB or more over the entire frequency band from 75 GHz to 110 GHz.
（実施例６）
樹脂：約８９．７６ｗｔ％
電磁波遮蔽物質１：約０．２４０ｗｔ％
電磁波遮蔽物質２：約１０．００ｗｔ％
を混合し、これらが均一に分散するように二軸押出機を用いることによって適宜撹拌させ、プレス加工をするなど既知の手法によって、約６ｍｍの厚さの電磁波シールド材を製造した。
Example 6
Resin: about 89.76 wt%
Electromagnetic wave shielding material 1: about 0.240 wt%
Electromagnetic wave shielding material 2: about 10.00 wt%
The mixture was mixed and appropriately stirred using a twin-screw extruder so as to disperse the mixture uniformly, and then pressed into an electromagnetic shielding material having a thickness of about 6 mm by a known method.
なお、実施例６の電磁波シールド材について、導電率及び表面抵抗率を測定してみたところ、導電率は約０．５６Ｓ／ｍであり、表面抵抗率は約３００Ω／□であった。When the electrical conductivity and surface resistivity of the electromagnetic shielding material of Example 6 were measured, the electrical conductivity was approximately 0.56 S/m and the surface resistivity was approximately 300 Ω/□.
図１１は、実施例６の電磁波シールド材の透過損失を示す図である。図１１の横軸には周波数［ＧＨｚ］を示し、図１１の縦軸には透過損失［ｄＢ］を示している。図１１に示すように、実施例６の電磁波シールド材は、７５ＧＨｚ～１１０ＧＨｚの周波数帯域全体に亘り、透過損失が３５ｄＢ以上であり、とりわけ、約９０ＧＨｚ～１１０ＧＨｚの周波数帯域全体では、遮蔽性能が４０ｄＢ以上であることがわかる。 Figure 11 is a diagram showing the transmission loss of the electromagnetic shielding material of Example 6. The horizontal axis of Figure 11 shows frequency [GHz], and the vertical axis of Figure 11 shows transmission loss [dB]. As shown in Figure 11, the electromagnetic shielding material of Example 6 has a transmission loss of 35 dB or more over the entire frequency band of 75 GHz to 110 GHz, and in particular, it can be seen that the shielding performance is 40 dB or more over the entire frequency band of approximately 90 GHz to 110 GHz.
図１２は、実施例６の電磁波シールド材の反射損失を示す図である。図１２の横軸には周波数［ＧＨｚ］を示し、図１２の縦軸には反射損失［ｄＢ］を示している。図１２に示すように、実施例６の電磁波シールド材は、６０ＧＨｚ～９０ＧＨｚの周波数帯域全体に亘り、反射損失が約７ｄＢ以上であることがわかる。 Figure 12 is a diagram showing the reflection loss of the electromagnetic shielding material of Example 6. The horizontal axis of Figure 12 shows frequency [GHz], and the vertical axis of Figure 12 shows reflection loss [dB]. As shown in Figure 12, it can be seen that the electromagnetic shielding material of Example 6 has a reflection loss of approximately 7 dB or more over the entire frequency band from 60 GHz to 90 GHz.
（実施例７）
樹脂：約８９．７７５ｗｔ％
電磁波遮蔽物質１：約０．２２５ｗｔ％
電磁波遮蔽物質２：約１０．００ｗｔ％
を混合し、これらが均一に分散するように二軸押出機を用いることによって適宜撹拌させ、プレス加工をするなど既知の手法によって、約６ｍｍの厚さの電磁波シールド材を製造した。
(Example 7)
Resin: about 89.775 wt%
Electromagnetic wave shielding material 1: about 0.225 wt%
Electromagnetic wave shielding material 2: about 10.00 wt%
The mixture was mixed and appropriately stirred using a twin-screw extruder so as to disperse the mixture uniformly, and then pressed into an electromagnetic shielding material having a thickness of about 6 mm by a known method.
なお、実施例７の電磁波シールド材について、導電率及び表面抵抗率を測定してみたところ、導電率は約０．５６Ｓ／ｍであり、表面抵抗率は約４００Ω／□であった。When the electrical conductivity and surface resistivity of the electromagnetic shielding material of Example 7 were measured, the electrical conductivity was approximately 0.56 S/m and the surface resistivity was approximately 400 Ω/□.
図１３は、実施例７の電磁波シールド材の透過損失を示す図である。図１３の横軸には周波数［ＧＨｚ］を示し、図１３の縦軸には透過損失［ｄＢ］を示している。図１３に示すように、実施例７の電磁波シールド材は、７５ＧＨｚ～１１０ＧＨｚの周波数帯域全体に亘り、透過損失が３０ｄＢ以上であり、とりわけ、約８０ＧＨｚ～１００ＧＨｚの周波数帯域全体では、遮蔽性能が３５ｄＢ以上、約１００ＧＨｚ～１１０ＧＨｚの周波数帯域全体では、遮蔽性能が４０ｄＢ以上、であることがわかる。 Figure 13 is a diagram showing the transmission loss of the electromagnetic shielding material of Example 7. The horizontal axis of Figure 13 shows frequency [GHz], and the vertical axis of Figure 13 shows transmission loss [dB]. As shown in Figure 13, the electromagnetic shielding material of Example 7 has a transmission loss of 30 dB or more over the entire frequency band of 75 GHz to 110 GHz, and in particular, the shielding performance is 35 dB or more over the entire frequency band of approximately 80 GHz to 100 GHz, and the shielding performance is 40 dB or more over the entire frequency band of approximately 100 GHz to 110 GHz.
図１４は、実施例７の電磁波シールド材の反射損失を示す図である。図１４の横軸には周波数［ＧＨｚ］を示し、図１４の縦軸には反射損失［ｄＢ］を示している。図１４に示すように、実施例７の電磁波シールド材は、６０ＧＨｚ～９０ＧＨｚの周波数帯域全体に亘り、反射損失が８ｄＢ以上であることがわかる。 Figure 14 is a diagram showing the reflection loss of the electromagnetic shielding material of Example 7. The horizontal axis of Figure 14 shows frequency [GHz], and the vertical axis of Figure 14 shows reflection loss [dB]. As shown in Figure 14, it can be seen that the electromagnetic shielding material of Example 7 has a reflection loss of 8 dB or more over the entire frequency band from 60 GHz to 90 GHz.
（実施例８）
樹脂：約８９．９１ｗｔ％
電磁波遮蔽物質１：約０．０９ｗｔ％
電磁波遮蔽物質２：約１０．００ｗｔ％
を混合し、これらが均一に分散するように二軸押出機を用いることによって適宜撹拌させ、プレス加工をするなど既知の手法によって、約６ｍｍの厚さの電磁波シールド材を製造した。
(Example 8)
Resin: Approximately 89.91 wt%
Electromagnetic wave shielding material 1: about 0.09 wt%
Electromagnetic wave shielding material 2: about 10.00 wt%
The mixture was mixed and appropriately stirred using a twin-screw extruder so as to disperse the mixture uniformly, and then pressed into an electromagnetic shielding material having a thickness of about 6 mm by a known method.
なお、実施例８の電磁波シールド材について、導電率及び表面抵抗率を測定してみたところ、導電率は約０．３３Ｓ／ｍであり、表面抵抗率は約５００Ω／□であった。When the electrical conductivity and surface resistivity of the electromagnetic shielding material of Example 8 were measured, the electrical conductivity was approximately 0.33 S/m and the surface resistivity was approximately 500 Ω/□.
図１５は、実施例８の電磁波シールド材の透過損失を示す図である。図１５の横軸には周波数［ＧＨｚ］を示し、図１５の縦軸には透過損失［ｄＢ］を示している。図１５に示すように、実施例８の電磁波シールド材は、７５ＧＨｚ～１１０ＧＨｚの周波数帯域全体に亘り、透過損失が３０ｄＢ以上であることがわかる。 Figure 15 is a diagram showing the transmission loss of the electromagnetic shielding material of Example 8. The horizontal axis of Figure 15 shows frequency [GHz], and the vertical axis of Figure 15 shows transmission loss [dB]. As shown in Figure 15, it can be seen that the electromagnetic shielding material of Example 8 has a transmission loss of 30 dB or more over the entire frequency band from 75 GHz to 110 GHz.
図１６は、実施例８の電磁波シールド材の反射損失を示す図である。図１６の横軸には周波数［ＧＨｚ］を示し、図１６の縦軸には反射損失［ｄＢ］を示している。図１６に示すように、実施例８の電磁波シールド材は、７５ＧＨｚ～１１０ＧＨｚの周波数帯域全体に亘り、反射損失が８ｄＢ以上であることがわかる。 Figure 16 is a diagram showing the reflection loss of the electromagnetic shielding material of Example 8. The horizontal axis of Figure 16 shows frequency [GHz], and the vertical axis of Figure 16 shows reflection loss [dB]. As shown in Figure 16, it can be seen that the electromagnetic shielding material of Example 8 has a reflection loss of 8 dB or more over the entire frequency band from 75 GHz to 110 GHz.
（実施例９）
樹脂：約８９．９２８ｗｔ％
電磁波遮蔽物質１：約０．０７２ｗｔ％
電磁波遮蔽物質２：約１０．００ｗｔ％
を混合し、これらが均一に分散するように二軸押出機を用いることによって適宜撹拌させ、プレス加工をするなど既知の手法によって、約６ｍｍの厚さの電磁波シールド材を製造した。
Example 9
Resin: Approximately 89.928 wt%
Electromagnetic wave shielding material 1: about 0.072 wt%
Electromagnetic wave shielding material 2: about 10.00 wt%
The mixture was mixed and appropriately stirred using a twin-screw extruder so as to disperse the mixture uniformly, and then pressed into an electromagnetic shielding material having a thickness of about 6 mm by a known method.
なお、実施例９の電磁波シールド材について、導電率及び表面抵抗率を測定してみたところ、導電率は約０．３３Ｓ／ｍであり、表面抵抗率は約７５０Ω／□であった。When the electrical conductivity and surface resistivity of the electromagnetic shielding material of Example 9 were measured, the electrical conductivity was approximately 0.33 S/m and the surface resistivity was approximately 750 Ω/□.
図１７は、実施例９の電磁波シールド材の透過損失を示す図である。図１７の横軸には周波数［ＧＨｚ］を示し、図１７の縦軸には透過損失［ｄＢ］を示している。図１７に示すように、実施例９の電磁波シールド材は、７５ＧＨｚ～１１０ＧＨｚの周波数帯域全体に亘り、透過損失が３０ｄＢ以上であることがわかる。 Figure 17 is a diagram showing the transmission loss of the electromagnetic shielding material of Example 9. The horizontal axis of Figure 17 shows frequency [GHz], and the vertical axis of Figure 17 shows transmission loss [dB]. As shown in Figure 17, it can be seen that the electromagnetic shielding material of Example 9 has a transmission loss of 30 dB or more over the entire frequency band from 75 GHz to 110 GHz.
図１８は、実施例９の電磁波シールド材の反射損失を示す図である。図１８の横軸には周波数［ＧＨｚ］を示し、図１８の縦軸には反射損失［ｄＢ］を示している。図１８に示すように、実施例９の電磁波シールド材は、７５ＧＨｚ～１１０ＧＨｚの周波数帯域全体に亘り、反射損失が７ｄＢ以上であることがわかる。 Figure 18 is a diagram showing the reflection loss of the electromagnetic shielding material of Example 9. The horizontal axis of Figure 18 shows frequency [GHz], and the vertical axis of Figure 18 shows reflection loss [dB]. As shown in Figure 18, it can be seen that the electromagnetic shielding material of Example 9 has a reflection loss of 7 dB or more over the entire frequency band from 75 GHz to 110 GHz.
（比較例１）
樹脂：約８９．５ｗｔ％
電磁波遮蔽物質１：約０．５ｗｔ％
電磁波遮蔽物質２：約１０．００ｗｔ％
を混合し、これらが均一に分散するように二軸押出機を用いることによって適宜撹拌させ、プレス加工をするなど既知の手法によって、約２ｍｍの厚さの電磁波シールド材を製造したものは、９５ＧＨｚ未満の透過損失が１５ｄＢを下回ったので、所要の遮蔽性能が得られないことが分かった。
(Comparative Example 1)
Resin: Approximately 89.5 wt%
Electromagnetic wave shielding material 1: about 0.5 wt%
Electromagnetic wave shielding material 2: about 10.00 wt%
The above ingredients were mixed, appropriately stirred using a twin-screw extruder so that they were uniformly dispersed, and then pressed into an electromagnetic shielding material having a thickness of about 2 mm. However, the transmission loss at frequencies below 95 GHz was less than 15 dB, indicating that the required shielding performance could not be obtained.
実施例１～９の電磁波シールド材の各々について、電磁波の反射損失は自由空間法によって、透過損失はＡＳＴＭ Ｄ４９３５に基づいて測定した。具体的には、反射損失は実施例１～９の電磁波シールド材に対して７５ＧＨｚから１１０ＧＨｚの電磁波を照射した後、試片の表面から反射されて出る信号強さと照射時の信号強さとの差から求めた。また、透過損失は、実施例１～９の電磁波シールド材に対して７５ＧＨｚから１１０ＧＨｚの電磁波を照射した後、試片を通過して出る信号強さと照射時の信号強さとの差から求めた。For each of the electromagnetic shielding materials of Examples 1 to 9, the electromagnetic wave reflection loss was measured by the free space method, and the transmission loss was measured based on ASTM D4935. Specifically, the reflection loss was determined by irradiating the electromagnetic shielding materials of Examples 1 to 9 with electromagnetic waves of 75 GHz to 110 GHz, and then measuring the difference in signal strength reflected from the surface of the specimen and the signal strength at the time of irradiation. The transmission loss was determined by irradiating the electromagnetic shielding materials of Examples 1 to 9 with electromagnetic waves of 75 GHz to 110 GHz, and then measuring the difference in signal strength transmitted through the specimen and the signal strength at the time of irradiation.
実施例１～９の電磁波シールド材における電磁波の反射損失及び透過損失は、いずれも、反射損失が６ｄＢ以上であって、かつ、透過損失が１５ｄＢ以上であることがわかる。加えて、実施例１～９の電磁波シールド材は、測定した周波数帯域全般での反射損失がフラットな傾向にあるため、電子回路設計がしやすいという利点もある。It can be seen that the electromagnetic wave reflection loss and transmission loss of the electromagnetic wave shielding materials of Examples 1 to 9 are both 6 dB or more in reflection loss and 15 dB or more in transmission loss. In addition, the electromagnetic wave shielding materials of Examples 1 to 9 tend to have flat reflection loss across the entire measured frequency band, which makes it easier to design electronic circuits.
参考のため、ランダムに選定した実施例２，３，６，７の電磁波シールド材については、周波数帯域の下限を６０ＧＨｚとして反射損失を計測してみた。その結果、いずれの電磁波シールド材については、反射損失が６ｄＢであることを確認した。For reference, the reflection loss was measured for the randomly selected electromagnetic shielding materials of Examples 2, 3, 6, and 7, with the lower limit of the frequency band set to 60 GHz. As a result, it was confirmed that the reflection loss for each of the electromagnetic shielding materials was 6 dB.
本実施例では、電磁波シールド材を自動車用近接レーダーに適用する例について説明したが、電磁波シールド材は、自動車用近接レーダー以外にも、７３ＧＨｚの周波数帯域を使用する携帯電話機・スマートフォン・ＰＤＡ・タブレット端末・パーソナルコンピュータなどに付帯する通信機器、７６ＧＨｚ～８３ＧＨｚの各種近接レーダーなどにも適用することができる。これらの場合にも、電子制御ユニット或いはこれに相当する部材自体又はその周辺に電磁波シールド材を貼付又は配置すればよい。
In this embodiment, an example of applying the electromagnetic shielding material to an automotive proximity radar has been described, but the electromagnetic shielding material can also be applied to communication devices attached to mobile phones, smartphones, PDAs, tablet terminals, personal computers, etc. that use the 73 GHz frequency band, various proximity radars of 76 GHz to 83 GHz, etc. In these cases, the electromagnetic shielding material can be attached or disposed on the electronic control unit or an equivalent member itself or in the vicinity thereof.
Claims (7)
電磁波の反射損失の絶対値が大きくなることに寄与する前記樹脂に含有される電磁波遮蔽物質１と、
電磁波の透過損失の絶対値が大きくなることに寄与する前記樹脂に含有される電磁波遮蔽物質２と、
を含む、電磁波シールド材であって、
前記各電磁波遮蔽物質（ただし、銀微粒子で焼結されていない）を前記樹脂に対して分散させる分散剤を含み、
その厚さが２ｍｍである場合に、７５ＧＨｚ～１１０ＧＨｚの周波数帯域全体に亘り、反射損失の絶対値が５ｄＢ以上であり、かつ、透過損失の絶対値が１５ｄＢ以上である、電磁波シールド材。 The main component is resin,
an electromagnetic wave shielding material 1 contained in the resin, which contributes to increasing the absolute value of the reflection loss of the electromagnetic wave;
an electromagnetic wave shielding material 2 contained in the resin, which contributes to increasing the absolute value of the electromagnetic wave transmission loss;
An electromagnetic wave shielding material comprising:
a dispersant for dispersing the electromagnetic wave shielding materials (not sintered with silver fine particles) in the resin;
An electromagnetic wave shielding material having a thickness of 2 mm , the absolute value of the reflection loss being 5 dB or more and the absolute value of the transmission loss being 15 dB or more over the entire frequency band from 75 GHz to 110 GHz.
前記各電磁波遮蔽物質はナノカーボンである、請求項１記載の電磁波シールド材。 The resin is a thermoplastic resin,
The electromagnetic wave shielding material according to claim 1 , wherein each of said electromagnetic wave shielding substances is nanocarbon.
前記各電磁波遮蔽物質は、カーボンナノチューブ、カーボンブラック、カーボンナノコイル、カーボンナノファイバー、グラフェン、フラーレンのうち、電磁波の反射損失の絶対値が大きくなることに寄与する前記電磁波遮蔽物質１と、電磁波の透過損失の絶対値が大きくなることに寄与する前記電磁波遮蔽物質２との任意の組合せである、請求項１記載の電磁波シールド材。 The resin is any one of polyamide resin, polyimide resin, polyamideimide resin, polyacetal resin, polycarbonate resin, polyethersulfone resin, polyetherketone resin, polyetherimide resin, polyalkylene terephthalate resin, acrylic resin, polysulfone resin, polyphenylene sulfide, polyolefin, polystyrene resin, syndiotactic polystyrene resin, acrylonitrile butadiene styrene resin, polyphenylene oxide resin, polybutylene, and liquid crystal polymer resin, or any combination of some of these,
2. The electromagnetic wave shielding material according to claim 1, wherein each of the electromagnetic wave shielding substances is an arbitrary combination of the electromagnetic wave shielding substance 1, which contributes to increasing the absolute value of the reflection loss of the electromagnetic wave, and the electromagnetic wave shielding substance 2, which contributes to increasing the absolute value of the transmission loss of the electromagnetic wave, selected from carbon nanotubes, carbon black, carbon nanocoils, carbon nanofibers, graphene, and fullerenes.
前記電磁波シールド材の厚さは２ｍｍ以上である、信号処理ユニット。 A signal processing unit comprising the electromagnetic shielding material according to any one of claims 1 to 5,
A signal processing unit, wherein the electromagnetic wave shielding material has a thickness of 2 mm or more.
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