JP4673573B2 - Method for manufacturing electromagnetic shielding material - Google Patents

Method for manufacturing electromagnetic shielding material Download PDF

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JP4673573B2
JP4673573B2 JP2004125413A JP2004125413A JP4673573B2 JP 4673573 B2 JP4673573 B2 JP 4673573B2 JP 2004125413 A JP2004125413 A JP 2004125413A JP 2004125413 A JP2004125413 A JP 2004125413A JP 4673573 B2 JP4673573 B2 JP 4673573B2
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electromagnetic wave
wave shielding
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resin
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JP2005311039A (en
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豊 林
武俊 中山
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Komatsu Seiren Co Ltd
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本発明は、少なくとも厚さ方向に導通性を有する電磁波シールド材に関する。   The present invention relates to an electromagnetic wave shielding material having conductivity in at least the thickness direction.

家庭電化製品、携帯電話機等の種々の電子機器が広く利用されており、これらを無線によって接続する技術も開発されている。しかしながら、電子機器から発生する電磁波によって、他の電子機器が誤作動するなど、電磁波による他への影響も懸念されている。従来、電磁波による影響を低減するために、アルミ箔等の金属箔からなる電磁波シールド材が開発されている。   Various electronic devices such as home appliances and mobile phones are widely used, and a technology for connecting them wirelessly has also been developed. However, there are concerns about other effects of electromagnetic waves such as malfunction of other electronic devices due to electromagnetic waves generated from the electronic devices. Conventionally, in order to reduce the influence of electromagnetic waves, an electromagnetic shielding material made of a metal foil such as an aluminum foil has been developed.

金属箔からなる従来の電磁波シールド材は、電磁波シールド性には優れるものの、強度、屈曲性・柔軟性等が良好でないため、取り付け時等に亀裂等が発生し、その部分の電磁波シールド性が低下する恐れがあった。
そこで、強度向上、及び軽量化・薄型化を目的として、樹脂フィルムや繊維布帛を基材とし、その上に金属箔や金属層からなる電磁波シールド層を設けた電磁波シールド材が提案されている。さらに屈曲性・柔軟性向上を目的として、上記基材上に、導電粒子含有樹脂層からなる電磁波シールド層を設けた電磁波シールド材も提案されている(特許文献1)。
特開2000−208984号公報
Although conventional electromagnetic shielding material made of metal foil is excellent in electromagnetic shielding properties, it does not have good strength, flexibility, flexibility, etc., so cracks etc. occur during installation, etc. There was a fear.
Therefore, for the purpose of improving the strength and reducing the weight and thickness, an electromagnetic shielding material has been proposed in which a resin film or a fiber fabric is used as a base material and an electromagnetic shielding layer made of a metal foil or a metal layer is provided thereon. Further, for the purpose of improving flexibility and flexibility, an electromagnetic wave shielding material in which an electromagnetic wave shielding layer made of a conductive particle-containing resin layer is provided on the base material has been proposed (Patent Document 1).
JP 2000-208984 A

通常、電磁波シールド材に入射した電磁波の電界成分から誘起される電流を、電磁波シールド層から取り除くにはアースが必要である。しかしながら、上記先行技術では、非導電性の基材を用いているため、電磁波シールド材全体で見た場合、その厚さ方向の導通性がなく、アースをとるためには、特別な処置を施す必要がある。
特に、電磁波シールドルームの壁面や天井等の面積の広い箇所に取り付けたり、ケーブルに巻き付けるなど、複数の電磁波シールド材を繋げたり一部重ねて使用する場合、繋ぎ部分や重なり部分の厚さ方向の導通が取れないため、よりアースが困難となっている。また、繋ぎ部分や重なり部分からの電磁波の漏洩を防止するために、導電テープ等を用いて目止めするなどの対応を余儀なくされている。
Usually, grounding is required to remove from the electromagnetic wave shielding layer the current induced from the electric field component of the electromagnetic wave incident on the electromagnetic wave shielding material. However, in the above prior art, since a non-conductive base material is used, there is no electrical conductivity in the thickness direction when viewed as a whole of the electromagnetic wave shielding material, and special measures are taken for grounding. There is a need.
In particular, when multiple electromagnetic shielding materials are connected or partially overlapped, such as attached to a large area such as the wall or ceiling of an electromagnetic shielding room, or wrapped around a cable, the thickness of the connecting part or overlapping part Since continuity cannot be obtained, grounding is more difficult. Further, in order to prevent leakage of electromagnetic waves from the connecting portion and the overlapping portion, it is necessary to take measures such as using a conductive tape or the like.

本発明は上記事情に鑑みてなされたものであり、電磁波シールド性及び強度に優れ、軽量化・薄型化を図ることができ、しかも使用に際し、少なくとも厚さ方向に導通性を有する電磁波シールド材、及びその製造方法を提供することを目的とする。   The present invention has been made in view of the above circumstances, has excellent electromagnetic shielding properties and strength, can be reduced in weight and thickness, and in use, has an electromagnetic shielding material having conductivity in at least the thickness direction, And it aims at providing the manufacturing method.

本発明者は上記課題を解決するべく鋭意検討し、以下の電磁波シールド材及びその製造方法を発明した。   The inventor has intensively studied to solve the above-mentioned problems, and invented the following electromagnetic wave shielding material and a method for producing the same.

本発明の電磁波シールド材の製造方法は、電磁波シールド層の少なくとも片面に、少なくとも厚さ方向に対して導通性を有する導通層を具備し、前記電磁波シールド層は凹凸形状とされている電磁波シールド材の製造方法であって、
表面が凹凸形状とされた離型シート上に前記電磁波シールド層と前記導通層との積層体を形成する工程(A)と、前記離型シートを剥離する工程(B)とを順次有すると共に、
工程(A)は、前記離型シート上に導電粒子を含む樹脂液を塗布・固化し、前記電磁波シールド層を形成する工程(A1)と、該形成された電磁波シールド層上に導電粒子を含む樹脂液を塗布・固化し、前記導通層を形成する工程(A2)とを含むことを特徴とする。
本発明において、導通層を構成する少なくとも一部の前記導電粒子の厚さ方向最大粒径(cmax)が、前記導通層を構成する樹脂層の最小厚さ(bmin)より大きく、その一端が前記電磁波シールド層に接触し、他端が前記樹脂層より突出していることが好ましい。
The method for producing an electromagnetic wave shielding material of the present invention comprises an electromagnetic wave shielding material having a conductive layer having conductivity at least in the thickness direction on at least one surface of the electromagnetic wave shielding layer, wherein the electromagnetic wave shielding layer has an uneven shape. A manufacturing method of
While sequentially having a step (A) of forming a laminate of the electromagnetic wave shielding layer and the conductive layer on a release sheet whose surface is uneven, and a step (B) of peeling the release sheet,
Step (A) includes applying and solidifying a resin liquid containing conductive particles on the release sheet to form the electromagnetic wave shielding layer (A1), and including the conductive particles on the formed electromagnetic wave shielding layer. And a step (A2) of forming a conductive layer by applying and solidifying a resin liquid .
In the present invention, the thickness direction maximum particle size (c max ) of at least a part of the conductive particles constituting the conductive layer is larger than the minimum thickness (b min ) of the resin layer constituting the conductive layer, and one end thereof It is preferable that is in contact with the electromagnetic shielding layer and the other end protrudes from the resin layer.

本発明の電磁波シールド材はさらに、前記導通層の前記電磁波シールド層と反対側の面に、接着剤層を具備することが好ましく、前記導通層を構成する少なくとも一部の前記導電粒子の厚さ方向最大粒径(cmax)が、前記樹脂層の最小厚さ(bmin)と、前記接着剤層の最小厚さ(dmin)の合計より大きく、その一端が前記電磁波シールド層に接触し、他端が前記接着剤層より突出していることが好ましい。 The electromagnetic wave shielding material of the present invention preferably further comprises an adhesive layer on the surface of the conductive layer opposite to the electromagnetic wave shielding layer, and the thickness of at least a part of the conductive particles constituting the conductive layer. direction maximum particle diameter (c max) is the minimum thickness of the resin layer and (b min), the greater than the sum of the minimum thickness of the adhesive layer (d min), one end is in contact with the electromagnetic wave shielding layer It is preferable that the other end protrudes from the adhesive layer.

なお、本明細書において、「最小厚さ」及び「最大厚さ」、「最大粒径」は、いずれも任意に選定した部分の断面を電子顕微鏡にて観察し、測定するものとする。断面選定にあたっては、電磁波シールド材がマクロ的に見て同様の構造を呈している部分を選定するものとする。仮に、突然変異部分、例えば、異物の混入等により極端に厚さが厚くなっているような箇所や、機械的損傷等を受けて層が部分的に薄くなっているような箇所等がある場合には、この部分は測定しないものとする。   In the present specification, “minimum thickness”, “maximum thickness”, and “maximum particle size” are all measured by observing a section of an arbitrarily selected portion with an electron microscope. In selecting a cross section, a portion where the electromagnetic shielding material has a similar structure as viewed macroscopically is selected. If there is a mutated part, for example, a part where the thickness is extremely thick due to mixing of foreign matter, or a part where the layer is partially thinned due to mechanical damage, etc. However, this part shall not be measured.

本発明によれば、電磁波シールド性、強度、屈曲性・柔軟性に優れ、軽量化・薄型化を図ることができ、しかも使用に際し、少なくとも厚さ方向に導通性を有する電磁波シールド材製造できる。
本発明による電磁波シールド材は、使用に際し、少なくとも厚さ方向に導通性を有するので、特別な処置を施すことなく、アースをとることができ、電磁波シールド材に入射し電磁波の電界成分から誘起される電流を効率良く取り除くことができる。
また、複数の電磁波シールド材を繋げたり一部重ねて使用する場合においても、特別な処置を施すことなく、繋ぎ部分や重なり部分の導通が取れ、アースを容易にとることができると共に、電磁波の漏洩を良好に防止することができる。
According to the present invention, electromagnetic shielding, strength, excellent flexibility and flexibility, it is possible to reduce the weight and thickness, yet in use, can produce an electromagnetic wave shielding material having a conductivity at least in the thickness direction .
The electromagnetic wave shielding material according to the present invention has conductivity in at least the thickness direction in use, so that it can be grounded without any special treatment and is induced from the electric field component of the electromagnetic wave incident on the electromagnetic wave shielding material. Current can be efficiently removed.
In addition, even when a plurality of electromagnetic shielding materials are connected or partially overlapped, the connecting portion and the overlapping portion can be conducted without taking special measures, and grounding can be easily taken. Leakage can be prevented satisfactorily.

「電磁波シールド材」
次に、図1に基づいて、本発明に係る一実施形態の電磁波シールド材の構造について説明する。同図は厚さ方向断面模式図であり、縮尺等については実際のものと異ならせてある。
"Electromagnetic wave shielding material"
Next, based on FIG. 1, the structure of the electromagnetic wave shielding material of one Embodiment which concerns on this invention is demonstrated. This figure is a schematic sectional view in the thickness direction, and the scale and the like are different from the actual ones.

本実施形態の電磁波シールド材1は、電磁波シールド層10の片面に、厚さ方向に対して導通性を有する導通層20、接着剤層30、離型シート40が順次積層形成されたものである。電磁波シールド材1は、いずれの面を電磁波入射側として使用しても良い。   The electromagnetic wave shielding material 1 of this embodiment is obtained by sequentially laminating a conductive layer 20, an adhesive layer 30, and a release sheet 40 having conductivity in the thickness direction on one surface of an electromagnetic wave shielding layer 10. . Any surface of the electromagnetic shielding material 1 may be used as the electromagnetic wave incident side.

(電磁波シールド層)
本実施形態において、電磁波シールド層10は、樹脂層11内に1種又は2種以上の多数の導電粒子12が分散した導電粒子含有樹脂層からなり、電磁波シールド性に優れると共に、強度、屈曲性・柔軟性に優れた層からなっている。
(Electromagnetic wave shielding layer)
In the present embodiment, the electromagnetic wave shielding layer 10 is composed of a conductive particle-containing resin layer in which a large number of one or two or more conductive particles 12 are dispersed in the resin layer 11, and has excellent electromagnetic wave shielding properties and strength and flexibility. -It consists of a layer with excellent flexibility.

樹脂層11を構成する樹脂としては、層を形成することができれば特に制限されるものではないが、ポリウレタン系、ポリエステル系、ポリアミド系、アクリル系、シリコーン系、フッ素系、ポリエチレン系、スチレンブタジエン系、ニトリルブタジエン系、エポキシ系等の合成樹脂が挙げられる。中でも、柔軟性に優れる点で、ウレタン系合成樹脂が好ましい。
樹脂層11は、樹脂の他、必要に応じて架橋剤、防炎剤、顔料、紫外線吸収剤、触媒等の添加剤を含むものであって良い。但し、電磁波シールド性の観点からは、添加剤の添加量は少ない方が好ましい。
The resin constituting the resin layer 11 is not particularly limited as long as the layer can be formed, but polyurethane, polyester, polyamide, acrylic, silicone, fluorine, polyethylene, styrene butadiene And synthetic resins such as nitrile butadiene and epoxy. Of these, urethane-based synthetic resins are preferred because of their excellent flexibility.
The resin layer 11 may contain additives such as a crosslinking agent, a flameproofing agent, a pigment, an ultraviolet absorber, and a catalyst, as necessary, in addition to the resin. However, from the viewpoint of electromagnetic shielding properties, it is preferable that the additive amount be small.

電磁波シールド層10の平均的な厚さ(a)は特に制限されないが、電磁波シールド性と、強度、屈曲性・柔軟性のバランスから、1〜80μm、特に1〜10μmが好ましい。
電磁波シールド層10の平均的な厚さ(a)が1μm未満では、電磁波シールド性や、強度、屈曲性・柔軟性が不充分となる恐れがあり、80μmを超えても、電磁波シールド性のそれ以上の向上はほとんど見られず、コスト的に不利である。
The average thickness (a) of the electromagnetic wave shielding layer 10 is not particularly limited, but is preferably 1 to 80 μm, particularly preferably 1 to 10 μm, from the balance of electromagnetic shielding properties, strength, flexibility and flexibility.
If the average thickness (a) of the electromagnetic wave shielding layer 10 is less than 1 μm, the electromagnetic wave shielding property, strength, flexibility and flexibility may be insufficient. The above improvement is hardly seen, which is disadvantageous in terms of cost.

導電粒子12としては、電磁波シールド性の観点から、平均長径2〜20μmの鱗片状導電粒子を用いることが好ましい。さらにはそれよりも粒径の小さい略球状導電粒子を少量併用することが特に好ましい。このように、形状及び粒径の異なる導電粒子が併用されていると、隣接する鱗片状導電粒子の間にそれよりも粒径の小さい略球状導電粒子が入り込み、金属の充填率が増加するため、電磁波シールド層10の表面抵抗値が低下し、優れた電磁波シールド性が発現する。   As the conductive particles 12, scale-like conductive particles having an average major axis of 2 to 20 μm are preferably used from the viewpoint of electromagnetic shielding properties. Further, it is particularly preferable to use a small amount of substantially spherical conductive particles having a smaller particle diameter. Thus, when conductive particles having different shapes and particle diameters are used in combination, substantially spherical conductive particles having a smaller particle diameter enter between adjacent scale-like conductive particles, and the metal filling rate increases. The surface resistance value of the electromagnetic wave shielding layer 10 decreases, and excellent electromagnetic wave shielding properties are exhibited.

導電粒子12の種類は特に制限されないが、金、銀、銅、アルミニウム、ニッケル、亜鉛、白金、チタン、コバルト、ベリリウム、パラジウム等の金属やその合金、導電性カーボン、これらの複合材料等が挙げられる。中でも、高導電性を有し、電磁波シールド性に優れることから、金、銀、銅、アルミニウム、ニッケル等が好ましく用いられる。
電磁波シールド層10中の導電粒子12含有率は特に制限はないが、電磁波シールド性と、強度、屈曲性・柔軟性のバランスから、10〜98質量%、特に70〜95質量%が好ましい。導電粒子12の種類によって好ましい範囲が異なるが、10質量%未満では電磁波シールド性が不充分となる恐れがあり、98質量%を超えると、強度、屈曲性・柔軟性が不充分となる恐れがある。
The type of the conductive particles 12 is not particularly limited, and examples thereof include metals such as gold, silver, copper, aluminum, nickel, zinc, platinum, titanium, cobalt, beryllium, palladium, alloys thereof, conductive carbon, and composite materials thereof. It is done. Among these, gold, silver, copper, aluminum, nickel, and the like are preferably used because they have high conductivity and excellent electromagnetic wave shielding properties.
Although the content rate of the conductive particles 12 in the electromagnetic wave shielding layer 10 is not particularly limited, it is preferably 10 to 98% by mass, particularly preferably 70 to 95% by mass, from the balance of electromagnetic shielding properties, strength, flexibility and flexibility. The preferred range varies depending on the type of the conductive particles 12, but if it is less than 10% by mass, the electromagnetic shielding properties may be insufficient, and if it exceeds 98% by mass, the strength, flexibility and flexibility may be insufficient. is there.

電磁波シールド層10の表面抵抗値は特に制限されないが、小さい程好ましく、1Ω/sq以下、特に0.1Ω/sq以下が好ましい。これによって、電磁波の電界成分から誘起される電流を効率的に導電し、優れた電磁波シールド性を発現する。   Although the surface resistance value of the electromagnetic wave shielding layer 10 is not particularly limited, it is preferably as small as possible, and is preferably 1 Ω / sq or less, particularly preferably 0.1 Ω / sq or less. As a result, the current induced from the electric field component of the electromagnetic wave is efficiently conducted, and excellent electromagnetic shielding properties are exhibited.

(導通層)
導通層20は厚さ方向に導通性を有する層であり、電磁波シールド層10を補強する補強層としての機能も有する層である。該層は、樹脂層21と1種又は2種以上の多数の導電粒子22とからなり、かつ各導電粒子22は少なくとも一部が樹脂層21に埋入された層構造を呈し、強度、屈曲性・柔軟性に優れた層からなっている。
樹脂層21を構成する樹脂や、導電粒子22の種類としては特に制限はなく、電磁波シールド層10を構成する樹脂層11や導電粒子12と同様のものが使用できる。また、樹脂層21も、樹脂層11と同様の添加剤を含むものであって良い。
(Conduction layer)
The conductive layer 20 is a layer having conductivity in the thickness direction, and also has a function as a reinforcing layer for reinforcing the electromagnetic wave shielding layer 10. The layer is composed of a resin layer 21 and one or more conductive particles 22, and each conductive particle 22 has a layer structure in which at least a part is embedded in the resin layer 21, and has a strength and a bending property. It consists of a layer with excellent properties and flexibility.
There is no restriction | limiting in particular as resin and the kind of conductive particle 22 which comprise the resin layer 21, The thing similar to the resin layer 11 and the conductive particle 12 which comprises the electromagnetic wave shield layer 10 can be used. The resin layer 21 may also contain the same additive as the resin layer 11.

樹脂層21の最小厚さ(bmin)は特に限定されないが、電磁波シールド層10の補強の観点から、3〜500μmが好ましい。樹脂層21の最小厚さが3μm未満では、補強効果が不充分となる恐れがあり、500μmを超えると、軽量化・薄型化の点で好ましくない。 The minimum thickness (b min ) of the resin layer 21 is not particularly limited, but is preferably 3 to 500 μm from the viewpoint of reinforcing the electromagnetic wave shielding layer 10. If the minimum thickness of the resin layer 21 is less than 3 μm, the reinforcing effect may be insufficient, and if it exceeds 500 μm, it is not preferable in terms of weight reduction and thickness reduction.

導電粒子22の形状は特に制限はないが、樹脂分散性や厚さ方向の導通性の観点から、針状、棒状、樹木状、球状等が好ましい。
その厚さ方向最大粒径(cmax)は特に制限はないが、0.01〜1000μmが好ましい。特に、ガスケット、壁紙、フレキシブルプリントサーキット、フラットフレキシブルケーブル等に貼着する電磁波シールドテープ等の用途では、10〜100μm程度が好ましい。
The shape of the conductive particles 22 is not particularly limited, but is preferably a needle shape, a rod shape, a tree shape, a spherical shape, or the like from the viewpoint of resin dispersibility and thickness direction conductivity.
The thickness direction maximum particle size (c max ) is not particularly limited, but is preferably 0.01 to 1000 μm. In particular, about 10-100 micrometers is preferable in uses, such as an electromagnetic wave shielding tape stuck on a gasket, wallpaper, a flexible printed circuit, a flat flexible cable, etc.

本実施形態では、少なくとも一部の導電粒子22の厚さ方向最大粒径(cmax)が、樹脂層21の最小厚さ(bmin)より大きく((cmax)>(bmin))、その一端(図では下端)が電磁波シールド層10に接触し、他端(図では上端)が樹脂層21より突出している。すなわち、各導電粒子22は単独で厚さ方向の導通材として機能しており、複数の導電粒子を厚さ方向に繋げて導通材とするよりも導通信頼性に優れている。 In this embodiment, the thickness direction maximum particle size (c max ) of at least some of the conductive particles 22 is larger than the minimum thickness (b min ) of the resin layer 21 ((c max )> (b min )), One end (lower end in the figure) is in contact with the electromagnetic wave shielding layer 10, and the other end (upper end in the figure) protrudes from the resin layer 21. That is, each conductive particle 22 functions alone as a conductive material in the thickness direction, and is more excellent in conduction reliability than connecting a plurality of conductive particles in the thickness direction to form a conductive material.

さらには、少なくとも一部の導電粒子22の厚さ方向最大粒径(cmax)が、樹脂層21の最小厚さ(bmin)と、接着剤層30の最小厚さ(dmin)の合計より大きく((cmax)>(bmin)+(dmin))、その一端が電磁波シールド層10に接触し、樹脂層21及び接着剤層30を貫通し、他端が接着剤層30より突出している。すなわち、各導電粒子22は単独で、導通層20及び接着剤30の厚さ方向の導通材として機能しており、接着剤層30に別途導通材を含有させる場合に比して、はるかに導通信頼性に優れている。 Furthermore, the thickness direction maximum particle size of at least part of the conductive particles 22 (c max) is the minimum thickness of the resin layer 21 and (b min), the total minimum thickness of the adhesive layer 30 (d min) Larger ((c max )> (b min ) + (d min )), one end of which is in contact with the electromagnetic wave shielding layer 10, penetrates the resin layer 21 and the adhesive layer 30, and the other end is from the adhesive layer 30. It protrudes. That is, each of the conductive particles 22 functions alone as a conductive material in the thickness direction of the conductive layer 20 and the adhesive 30, and is much more conductive than when the adhesive layer 30 contains a separate conductive material. Excellent reliability.

導電粒子22の種類は特に制限はなく、電磁波シールド層10を構成する導電粒子12と同様のものが用いられる。
導通層20中の導電粒子22含有率は特に制限されないが、導通性、強度、屈曲性・柔軟性の観点から、1〜95質量%、特に3〜30質量%が好ましい。導電粒子22の種類によって好ましい範囲は異なるが、1質量%未満では導通性が不充分となる恐れがあり、95質量%を超えると、強度、屈曲性・柔軟性が不充分となる恐れがある。
There is no restriction | limiting in particular in the kind of electrically-conductive particle 22, The thing similar to the electrically-conductive particle 12 which comprises the electromagnetic wave shield layer 10 is used.
The content of the conductive particles 22 in the conductive layer 20 is not particularly limited, but is preferably 1 to 95% by mass, particularly 3 to 30% by mass from the viewpoints of conductivity, strength, flexibility, and flexibility. The preferred range varies depending on the type of the conductive particles 22, but if it is less than 1% by mass, the conductivity may be insufficient, and if it exceeds 95% by mass, the strength, flexibility and flexibility may be insufficient. .

(接着剤層)
接着剤層30は、電磁波シールド材1を、ガスケットやケーブル等の種々の部材や、電磁波シールドルームの壁面や天井等に容易に貼着するために設けられるものである。該層を設けることで、取り付け時に接着剤を塗布する等の作業が不要となり、取り付け作業が著しく簡略化される。なお、接着剤層30の存在によって電磁波シールド性が損なわれることはない。
(Adhesive layer)
The adhesive layer 30 is provided to easily adhere the electromagnetic shielding material 1 to various members such as gaskets and cables, the wall surface and ceiling of the electromagnetic shielding room, and the like. By providing the layer, an operation such as applying an adhesive at the time of attachment becomes unnecessary, and the attachment operation is remarkably simplified. The presence of the adhesive layer 30 does not impair the electromagnetic shielding properties.

接着剤層30を構成する接着剤としては特に制限されないが、アクリル系粘着剤、エポキシ系粘着剤、シリコーン系粘着剤等が挙げられ、1種又は2種以上を用いることができる。中でも、汎用性やコストの観点から、アクリル系粘着剤が好ましく用いられる。
電磁波シールド材1において、接着剤層30は平面視略全面に渡って形成されている。接着剤層30の形成面積は大きい程、面全体を均一に接着することができ好適である。但し、良好な接着力が得られれば、接着剤層30は平面視ドット状や格子状等、部分的に形成されていても良い。
Although it does not restrict | limit especially as an adhesive agent which comprises the adhesive bond layer 30, An acrylic adhesive, an epoxy adhesive, a silicone adhesive etc. are mentioned, 1 type (s) or 2 or more types can be used. Among them, an acrylic pressure-sensitive adhesive is preferably used from the viewpoint of versatility and cost.
In the electromagnetic wave shielding material 1, the adhesive layer 30 is formed over substantially the entire surface in a plan view. The larger the formation area of the adhesive layer 30, the more preferable it is that the entire surface can be adhered uniformly. However, the adhesive layer 30 may be partially formed in a dot shape or a lattice shape in plan view as long as a good adhesive force is obtained.

(離型シート)
接着剤層30の露出面は離型シート40により被覆され、保護されている。これによって、電磁波シールド材1を取り付ける前に、接着剤層30がそれ自身や他の部材等に接着することを防止できる。電磁波シールド材1の取り付け時には、離型シート40を剥離し、接着剤層30を露出させて施工する。
離型シート40は樹脂が接着しないように表面処理されたシート(フィルムを含む)であり、その種類は特に制限はないが、離型紙等が好ましく用いられる。表面形状は、ミダル、フルダル等の多少凹凸を有するもの、格子状やストライプ状等の規則的な凹凸を有するもの、天然皮革の表面形状に似せた凹凸を有するもの等がある。
(Release sheet)
The exposed surface of the adhesive layer 30 is covered and protected by a release sheet 40. Thereby, before attaching the electromagnetic wave shielding material 1, it can prevent that the adhesive bond layer 30 adhere | attaches itself or another member. When the electromagnetic wave shielding material 1 is attached, the release sheet 40 is peeled off, and the adhesive layer 30 is exposed to be applied.
The release sheet 40 is a sheet (including a film) that has been surface-treated so that the resin does not adhere to it, and the type thereof is not particularly limited, but release paper or the like is preferably used. Surface profile, Se Midaru, those with some irregularities, such as full-dull, those having a regular unevenness of lattice or stripe like, there is such having irregularities resembling the surface shape of the natural leather.

電磁波シールド材1は以上のように構成され、本実施形態では、電磁波シールド層10を補強する補強層を、厚さ方向に導通性を有する導通層20により構成した。さらに、導通層20を、樹脂層21と少なくとも一部が樹脂層21に埋入された導電粒子22とを具備してなる導電粒子含有樹脂層により構成し、少なくとも一部の導電粒子22の厚さ方向最大粒径(cmax)を樹脂層21及び接着剤層30の合計厚(bmin)+(dmin)より大きく設定し、その一端が電磁波シールド層10に接触し、他端が接着剤層30より突出するように構成した。 The electromagnetic wave shielding material 1 is configured as described above, and in this embodiment, the reinforcing layer that reinforces the electromagnetic wave shielding layer 10 is configured by the conductive layer 20 having conductivity in the thickness direction. Furthermore, the conductive layer 20 is constituted by a conductive particle-containing resin layer comprising a resin layer 21 and conductive particles 22 at least partially embedded in the resin layer 21, and the thickness of at least a part of the conductive particles 22. The longitudinal maximum particle size (c max ) is set to be larger than the total thickness (b min ) + (d min ) of the resin layer 21 and the adhesive layer 30, one end thereof is in contact with the electromagnetic wave shielding layer 10, and the other end is bonded. It was configured to protrude from the agent layer 30.

すなわち、本実施形態の電磁波シールド材1では、導通層20を構成する各導電粒子22が導通層20の樹脂層21及び接着剤層30を貫通し、厚さ方向に導通する導通材として機能する。したがって、電磁波シールド材1は、取り付け時に剥離する離型シート40を除く有効部分(電磁波シールド層10〜接着剤層30)が、厚さ方向の導通性を有するので、特別な処置を施すことなく、アースをとることができ、電磁波シールド材1に入射し電磁波の電界成分から誘起される電流を効率良く取り除くことができる。
また、電磁波シールドルームの壁面や天井等の面積の広い箇所に取り付けたり、ケーブルに巻き付けるなど、複数の電磁波シールド材1を繋げたり一部重ねて使用する場合においても、特別な処置を施すことなく、繋ぎ部分や重なり部分の導通が取れ、アースを容易にとることができると共に、電磁波の漏洩を良好に防止することができる。
That is, in the electromagnetic wave shielding material 1 of the present embodiment, each conductive particle 22 constituting the conductive layer 20 penetrates the resin layer 21 and the adhesive layer 30 of the conductive layer 20 and functions as a conductive material that conducts in the thickness direction. . Therefore, since the electromagnetic wave shielding material 1 has an effective portion (electromagnetic wave shielding layer 10 to adhesive layer 30) excluding the release sheet 40 that is peeled off at the time of attachment, it has electrical conductivity in the thickness direction. Therefore, it is possible to remove the current that is incident on the electromagnetic wave shielding material 1 and is induced from the electric field component of the electromagnetic wave.
In addition, even when a plurality of electromagnetic shielding materials 1 are connected or partially overlapped, such as being attached to a large area such as a wall surface or ceiling of an electromagnetic shielding room, or wrapped around a cable, no special measures are taken. In addition, the connecting portion and the overlapping portion can be electrically connected to each other so that the ground can be easily taken and the leakage of the electromagnetic wave can be satisfactorily prevented.

本実施形態の電磁波シールド材1の厚さ方向の導通性は特に制限はないが、電磁波シールド材1に入射した電磁波の電界成分から誘起される電流を効率良く導通させるには、厚さ方向の抵抗値が5Ω以下、特に0.5Ω以下であることが好ましい。厚さ方向の抵抗値は小さい程良いが、市販の導電粒子や樹脂を用いて成膜すると、導通層20の強度、屈曲性、柔軟性、外観等の兼ね合いもあり、現状では、0.001Ω程度が下限となっている。
本明細書で言う「厚さ方向の抵抗値」は、取り付け時に剥離する離型シート等を除く有効部分の厚さ方向の抵抗値を意味するものとし、その測定法については「実施例」で説明する。
Although there is no particular limitation on the conductivity in the thickness direction of the electromagnetic shielding material 1 of the present embodiment, in order to efficiently conduct the current induced from the electric field component of the electromagnetic wave incident on the electromagnetic shielding material 1, It is preferable that the resistance value is 5Ω or less, particularly 0.5Ω or less. The smaller the resistance value in the thickness direction, the better. However, when a film is formed using commercially available conductive particles or resin, there is a tradeoff between the strength, flexibility, flexibility, appearance, etc. of the conductive layer 20, and at present 0.001Ω. The degree is the lower limit.
The “resistance value in the thickness direction” referred to in this specification means the resistance value in the thickness direction of the effective portion excluding the release sheet that is peeled off at the time of attachment, and the measurement method is described in “Example”. explain.

本実施形態では、少なくとも一部の導電粒子22の厚さ方向最大粒径(cmax)を樹脂層21及び接着剤層30の合計厚(bmin)+(dmin)より大きく設定することで、導通層20を構成する導電粒子22でもって、接着剤層30の厚さ方向の導通性も確保している。これによって、上記した如く、樹脂層21及び接着剤層30が同一の導通材で導通されるので高い導通信頼性が確保でき、さらには、接着剤層30を形成する際には、導通性のない汎用接着剤を用いれば良いので、生産性、コスト的にも有利である。 In the present embodiment, by setting the maximum particle size (c max ) in the thickness direction of at least some of the conductive particles 22 to be larger than the total thickness (b min ) + (d min ) of the resin layer 21 and the adhesive layer 30. The conductive particles 22 constituting the conductive layer 20 ensure the conductivity in the thickness direction of the adhesive layer 30. Accordingly, as described above, since the resin layer 21 and the adhesive layer 30 are conducted with the same conducting material, high conduction reliability can be ensured. Furthermore, when the adhesive layer 30 is formed, the conductive layer 21 is electrically conductive. This is advantageous in terms of productivity and cost.

本実施形態の電磁波シールド材1では、導通層20が補強層として機能するので、充分な強度を有する。また、電磁波シールド層10や導通層20を樹脂を主体とする層で構成したので、屈曲性・柔軟性も良好で、軽量化・薄型化にも対応できる。   In the electromagnetic wave shielding material 1 of this embodiment, since the conduction | electrical_connection layer 20 functions as a reinforcement layer, it has sufficient intensity | strength. In addition, since the electromagnetic wave shielding layer 10 and the conductive layer 20 are composed of a resin-based layer, the flexibility and flexibility are good, and the weight and thickness can be reduced.

なお、電磁波シールド材1は一実施形態に過ぎず、本発明の趣旨を逸脱しない範囲内において、適宜設計を変更することができる。
電磁波シールド層10や導通層20は、屈曲性・柔軟性の観点から、上記したような導電粒子含有樹脂層が好適であるが、いずれか一方又は双方をアルミニウム箔、銅箔、金箔等の金属箔層や、蒸着、イオンプレーディング、スパッタリング等にて成膜された金属層等により構成しても良い。この場合にも、電磁波シールド層10〜導通層20が厚さ方向に導通性を有するものとなる。但し、導通層20を金属箔層や金属層等により構成する場合には、屈曲性・柔軟性は相対的に低下する。
In addition, the electromagnetic wave shielding material 1 is only one embodiment, and the design can be changed as appropriate without departing from the spirit of the present invention.
The electromagnetic wave shielding layer 10 and the conductive layer 20 are preferably the above-described conductive particle-containing resin layer from the viewpoint of flexibility and flexibility, but either one or both of them is a metal such as an aluminum foil, a copper foil, or a gold foil. You may comprise by a foil layer, the metal layer etc. which were formed into a film by vapor deposition, ion plating, sputtering, etc. Also in this case, the electromagnetic wave shielding layer 10 to the conductive layer 20 have conductivity in the thickness direction. However, when the conductive layer 20 is formed of a metal foil layer, a metal layer, or the like, flexibility and flexibility are relatively lowered.

本実施形態では、電磁波シールド層10と導通層20を一層ずつ設ける場合についてのみ説明したが、一方又は双方を複数設けても良い。例えば、電磁波シールド層10の両面に導通層20を設ける、一対の電磁波シールド層10間に導通層20を挟持させる、電磁波シールド層10と導通層20との積層体を複数対積層する等の構成を採用しても良い。   In the present embodiment, only the case where the electromagnetic wave shielding layer 10 and the conductive layer 20 are provided one by one has been described. However, one or both may be provided. For example, the conductive layer 20 is provided on both surfaces of the electromagnetic wave shield layer 10, the conductive layer 20 is sandwiched between the pair of electromagnetic wave shield layers 10, and a plurality of laminated bodies of the electromagnetic wave shield layer 10 and the conductive layer 20 are laminated. May be adopted.

また、接着剤層30を設け、厚さ方向の導通性を持たせることは好適であるが、本発明は、接着剤層30に厚さ方向の導通性を持たせることや、接着剤層30を導通層20の電磁波シールド層10と反対側の面に設けることは必須ではなく、さらには接着剤層30及びこれを保護する離型シート40を設けること自体も必須ではない。接着剤層30を設けない場合には、少なくとも一部の導電粒子22の厚さ方向最大粒径(cmax)を、樹脂層21の最小厚さ(bmin)より大きく設定し、その一端が電磁波シールド層10に接触し、他端が樹脂層21より突出するように構成すれば、導通信頼性について上記実施形態と同様の効果が得られる。
その他、必要に応じて 他の層を追加形成することも差し支えない。
In addition, although it is preferable to provide the adhesive layer 30 to provide conductivity in the thickness direction, the present invention provides the adhesive layer 30 to provide conductivity in the thickness direction, or the adhesive layer 30. Is not necessarily provided on the surface of the conductive layer 20 opposite to the electromagnetic wave shielding layer 10, and it is not essential to provide the adhesive layer 30 and the release sheet 40 for protecting the adhesive layer 30. When the adhesive layer 30 is not provided, the maximum particle size (c max ) in the thickness direction of at least some of the conductive particles 22 is set larger than the minimum thickness (b min ) of the resin layer 21, and one end thereof is If it comprises so that the electromagnetic wave shielding layer 10 may be contacted and the other end may protrude from the resin layer 21, the effect similar to the said embodiment can be acquired about conduction | electrical_connection reliability.
In addition, other layers may be additionally formed as necessary.

「電磁波シールド材の製造方法」
次に、電磁波シールド材1の製造方法の一例について説明する。
"Method of manufacturing electromagnetic shielding material"
Next, an example of the manufacturing method of the electromagnetic wave shielding material 1 will be described.

(工程(A))
はじめに、離型シート上に電磁波シールド層10と導通層20との積層体を形成する。該積層体は例えば、離型シート上に、導電粒子12を含む樹脂液を塗布・固化し、電磁波シールド層10を成膜し(工程(A1))、その上にさらに、導電粒子22を含む樹脂液を塗布・固化し、導通層20を成膜する(工程(A2))ことで形成できる。工程(A1)と工程(A2)の順序は逆であっても構わない。
(Process (A))
First, the laminated body of the electromagnetic wave shielding layer 10 and the conduction | electrical_connection layer 20 is formed on a release sheet. For example, the laminate includes applying and solidifying a resin liquid containing conductive particles 12 on a release sheet to form an electromagnetic wave shielding layer 10 (step (A1)), and further including conductive particles 22 thereon. The conductive layer 20 can be formed by applying and solidifying the resin liquid and forming the conductive layer 20 (step (A2)). The order of the step (A1) and the step (A2) may be reversed.

離型シートとしては、離型シート40と同様のものが使用できる。離型シートは表面形状が凹凸のあるもの、この例では、用いる離型シートの表面形状に沿った形状の電磁波シールド層10と導通層20が形成されることとなる。さらにはその上に形成される接着剤層30等もその形状の影響を受けることとなる。 As the release sheet, the same one as the release sheet 40 can be used. Release sheet surface shape in which a concave-convex, in this example, so that the conductive layer 20 and the electromagnetic wave shielding layer 10 having a shape along the surface shape of the release sheet used is formed. Furthermore, the adhesive layer 30 and the like formed thereon are also affected by the shape.

例えば、離型シートとして、表面に格子状等の規則的な凹凸を有する離型シートを用いる場合、図2に示すように、得られる電磁波シールド材1は、電磁波シールド層10が離型シートの表面凹凸形状に沿った低部10Xと高部10Yとを繰り返し有するものとなる。また、その上に形成される層が電磁波シールド層10の形状に沿ったものとなり、導通層20や接着剤層30は、電磁波シールド層10の低部10X上が相対的に厚く、高部10Y上が相対的に薄くなる傾向にある。この場合、導通層の最小厚さ(bmin)、接着剤層の最小厚さ(dmin)は、高部10Y上に形成された部分の厚さに相当する。なお、図面では、例として接着剤層の最小厚さ(dmin)が0の場合について図示してある。 For example, when a release sheet having regular irregularities such as a lattice shape on the surface is used as the release sheet, as shown in FIG. 2, the obtained electromagnetic wave shielding material 1 has an electromagnetic wave shielding layer 10 of the release sheet. It has the low part 10X and the high part 10Y along the surface uneven | corrugated shape repeatedly. In addition, the layer formed thereon is in conformity with the shape of the electromagnetic wave shielding layer 10, and the conductive layer 20 and the adhesive layer 30 are relatively thick on the lower part 10X of the electromagnetic wave shielding layer 10 and the higher part 10Y. The top tends to be relatively thin. In this case, the minimum thickness of the conductive layer (b min), the minimum thickness of the adhesive layer (d min) is equivalent to the thickness of the portion formed on the higher portion 10Y. In the drawing, as an example, the case where the minimum thickness (d min ) of the adhesive layer is 0 is shown.

工程(A1)、工程(A2)で用いる樹脂液は、樹脂層(11又は21)をなす樹脂を含むもので、樹脂を加熱溶融し液状としたもの、樹脂を溶剤(水、ジメチルホルムアミド、トルエン、キシレン、メチルエチルケトン等)に溶解した溶液、樹脂を水等に乳化分散したエマルジョン液等に、導電粒子(12又は22)を分散させて調製できる。
導電粒子の混合作業性や塗工性等を考慮すれば、樹脂を溶剤に溶解した溶液やエマルジョン液を用いることが好ましい。この場合、樹脂液中の液量は特に制限はないが、樹脂10質量部に対して10〜200質量部が好ましい。
また、樹脂層(11又は21)の組成に応じて、用いる樹脂液には、必要に応じて架橋剤、防炎剤、顔料、紫外線吸収剤、触媒等の添加剤を配合する。
The resin liquid used in the step (A1) and the step (A2) includes a resin forming the resin layer (11 or 21), and the resin is heated and melted to form a liquid, and the resin is a solvent (water, dimethylformamide, toluene). In addition, the conductive particles (12 or 22) can be dispersed in a solution dissolved in xylene, methyl ethyl ketone, etc.), an emulsion solution in which a resin is emulsified and dispersed in water or the like.
In view of mixing workability and coating property of the conductive particles, it is preferable to use a solution or emulsion solution in which a resin is dissolved in a solvent. In this case, the amount of the liquid in the resin liquid is not particularly limited, but is preferably 10 to 200 parts by mass with respect to 10 parts by mass of the resin.
Moreover, according to the composition of the resin layer (11 or 21), additives such as a crosslinking agent, a flameproofing agent, a pigment, an ultraviolet absorber, and a catalyst are blended in the resin liquid to be used as necessary.

樹脂液の塗布方法は特に制限されないが、ロールコータ、ロッドコータ、ナイフコータ、グラビアコータ、Tダイ等の押出コータ等を用いる方法が挙げられる。
塗膜の固化方法も特に制限されないが、冷却、あるいは60〜120℃程度で加熱、乾燥するなどして、固化することができる。
The method for applying the resin liquid is not particularly limited, and examples thereof include a method using an extrusion coater such as a roll coater, a rod coater, a knife coater, a gravure coater, and a T die.
The method for solidifying the coating film is not particularly limited, but it can be solidified by cooling or heating and drying at about 60 to 120 ° C.

電磁波シールド層10及び/又は導通層20が複数ある場合には、積層構造に応じて、成膜を繰り返せば良い。   When there are a plurality of electromagnetic shielding layers 10 and / or conductive layers 20, film formation may be repeated according to the laminated structure.

(工程(B))
以上のようにして電磁波シールド層10と導通層20を成膜した後、離型シートを剥離する。これによって、電磁波シールド層10と導通層20との積層体が得られる。接着剤層30のない電磁波シールド材では、これで製造は完了する。
(Process (B))
After forming the electromagnetic wave shielding layer 10 and the conductive layer 20 as described above, the release sheet is peeled off. Thereby, a laminate of the electromagnetic wave shielding layer 10 and the conductive layer 20 is obtained. With the electromagnetic wave shielding material without the adhesive layer 30, the production is completed.

(工程(C))
次に、別の離型シート40を用意し、この上に接着剤層30を形成する。接着剤層30は、例えば、アクリル系粘着剤、エポキシ系粘着剤、シリコーン系粘着剤等を含む接着剤液を塗布・固化することで成膜できる。塗布方法や固化方法は、電磁波シールド層10や導通層20と同様である。
(Process (C))
Next, another release sheet 40 is prepared, and the adhesive layer 30 is formed thereon. The adhesive layer 30 can be formed by applying and solidifying an adhesive liquid containing, for example, an acrylic adhesive, an epoxy adhesive, a silicone adhesive, and the like. The application method and the solidifying method are the same as those of the electromagnetic wave shielding layer 10 and the conductive layer 20.

(工程(D))
最後に、工程(B)で得られた電磁波シールド層10と導通層20との積層体と、工程(C)で得られた離型シート40と接着剤層30との積層体とを、導通層20と接着剤層30とが対向するように貼着する。
貼着方法は特に制限はないが、室温〜100℃程度のニップロールを用いて貼り合せるラミネート法等が挙げられる。
(Process (D))
Finally, the laminate of the electromagnetic wave shielding layer 10 and the conductive layer 20 obtained in the step (B) and the laminate of the release sheet 40 and the adhesive layer 30 obtained in the step (C) are electrically connected. Adhering is performed so that the layer 20 and the adhesive layer 30 face each other.
Although there is no restriction | limiting in particular in the sticking method, The laminating method etc. which are pasted together using the nip roll of room temperature-about 100 degreeC are mentioned.

以上のようにして、上記実施形態の電磁波シールド材1を容易に製造することができる。なお、上記製造方法は一例に過ぎず、これに限定されるものではない。例えば、工程(B)は工程(D)後に実施することもできる。   As described above, the electromagnetic wave shielding material 1 of the above embodiment can be easily manufactured. In addition, the said manufacturing method is only an example and is not limited to this. For example, the step (B) can be performed after the step (D).

次に、本発明に係る実施例について説明する。
(評価項目及び評価方法)
各例における評価項目及び評価方法を示す。
1.電子顕微鏡観察
電磁波シールド材の断面を走査型電子顕微鏡((株)トプコン製 ABT−32)にて観察し、導電粒子の粒径、各種層厚を測定した。
2.電磁波シールド性
電磁波シールド材の電磁波シールド性を、KEC法に基づき、10MHz〜1GHzの領域で測定した。
3.表面抵抗値
電磁波シールド層の表面抵抗値を、表面抵抗測定器ロレスターEP(三菱化学製)にて測定した。
4.厚さ方向の抵抗値
離型紙を除く積層体(電磁波シールド層〜接着剤層)の厚さ方向の抵抗値を測定した。測定は、デジタルマルチメーター7555(横川電気製)を用い、一対の真鋳製直方体(100g)間に試料を挟み、実施した。真鋳製直方体の試料を挟持する面の寸法は25mm×25mmとした。
Next, examples according to the present invention will be described.
(Evaluation items and evaluation methods)
Evaluation items and evaluation methods in each example are shown.
1. Electron Microscope Observation The cross section of the electromagnetic wave shielding material was observed with a scanning electron microscope (ABT-32 manufactured by Topcon Corporation), and the particle size and various layer thicknesses of the conductive particles were measured.
2. Electromagnetic wave shielding property The electromagnetic wave shielding property of the electromagnetic wave shielding material was measured in the region of 10 MHz to 1 GHz based on the KEC method.
3. Surface Resistance Value The surface resistance value of the electromagnetic wave shielding layer was measured with a surface resistance measuring instrument Lorester EP (manufactured by Mitsubishi Chemical).
4). Resistance value in the thickness direction The resistance value in the thickness direction of the laminate (electromagnetic wave shielding layer to adhesive layer) excluding the release paper was measured. The measurement was carried out by using a digital multimeter 7555 (manufactured by Yokogawa Electric) and sandwiching a sample between a pair of straight cast cuboids (100 g). The dimension of the surface for sandwiching the sample of the true cast cuboid was 25 mm × 25 mm.

(実施例1)
以下のようにして、図1に示した電磁波シールド材を製造した。
鱗片状銀粒子(平均長径6μm 、平均短径2μm)36質量%、ポリウレタン樹脂4質量%、及びN,N−ジメチルホルムアミド/トルエン混合溶媒(混合質量比30/70)60質量%からなる電磁波シールド層形成用樹脂液(S1)を調製した。
表面が比較的平坦なフルダル用ポリプロピレン離型紙上に、樹脂液(S1)をコンマコータにてスリット40μmで塗布し、120℃で3分間乾燥することにより、平均的な厚さ(a)=5μm 、銀含有率90.0質量%の電磁波シールド層を形成した。
Example 1
The electromagnetic wave shielding material shown in FIG. 1 was manufactured as follows.
Electromagnetic wave shield comprising 36% by mass of flaky silver particles (average major axis 6 μm, average minor axis 2 μm), 4% by mass of polyurethane resin, and 60% by mass of N, N-dimethylformamide / toluene mixed solvent (mixing mass ratio 30/70). A layer forming resin solution (S1) was prepared.
An average thickness (a) = 5 μm is obtained by applying the resin liquid (S1) with a slit of 40 μm with a comma coater on a polypropylene release paper for full dull having a relatively flat surface and drying at 120 ° C. for 3 minutes. An electromagnetic wave shielding layer having a silver content of 90.0% by mass was formed.

次に、略球状銅粒子5質量%、ポリウレタン樹脂20質量%、及びN,N−ジメチルホルムアミド/メチルエチルケトン混合溶媒(混合質量比35/65)75質量%からなる導通層形成用樹脂液(S2)を調製した。
樹脂液(S2)を上記電磁波シールド層上にコンマコータにてスリット200μmで塗布し、その後電磁波シールド層と同条件で加熱乾燥し、樹脂層最小厚さ(bmin)=30μm、銅粒子の厚さ方向最大粒径(cmax)=70μm、銅含有率20質量%の導通層を形成した。
以上のようにして、電磁波シールド層と導通層との積層体を形成した後、これを離型紙から剥離した。
Next, a conductive layer forming resin liquid (S2) comprising 5% by mass of substantially spherical copper particles, 20% by mass of polyurethane resin, and 75% by mass of a mixed solvent of N, N-dimethylformamide / methyl ethyl ketone (mixing mass ratio 35/65). Was prepared.
The resin liquid (S2) is applied onto the electromagnetic wave shielding layer with a comma coater with a slit of 200 μm, and then heated and dried under the same conditions as the electromagnetic wave shielding layer. The resin layer minimum thickness (b min ) = 30 μm, the thickness of the copper particles A conductive layer having a maximum directional particle size (c max ) of 70 μm and a copper content of 20% by mass was formed.
After forming the laminated body of the electromagnetic wave shielding layer and the conductive layer as described above, it was peeled from the release paper.

次に、粘着性アクリル樹脂30質量%及びトルエン70質量%からなる接着剤液(S3)を調製した。別途、表面が平坦なシリコーン離型紙を用意し、この上に、接着剤液(S3)をコンマコータにてスリット100μmで塗布し、100℃で2分間乾燥することにより、最小厚さ(dmin)=30μm、最大厚さ(dmax)=30μmの接着剤層を形成し、離型紙付き接着剤層を得た。
最後に、電磁波シールド層と導通層との積層体と、この離型紙付き接着剤層とを、導通層/接着剤層が対向するように重ね、これを80℃のニップロールにてラミネートし、本発明の電磁波シールド材を得た。
Next, an adhesive liquid (S3) composed of 30% by mass of an adhesive acrylic resin and 70% by mass of toluene was prepared. Separately, a silicone release paper having a flat surface is prepared, and an adhesive liquid (S3) is applied on this with a comma coater with a slit of 100 μm and dried at 100 ° C. for 2 minutes, whereby the minimum thickness (d min ) An adhesive layer with a thickness of 30 μm and a maximum thickness (d max ) = 30 μm was formed to obtain an adhesive layer with release paper.
Finally, the laminate of the electromagnetic wave shielding layer and the conductive layer and this adhesive layer with release paper are stacked so that the conductive layer / adhesive layer face each other, and this is laminated with a nip roll at 80 ° C. An electromagnetic shielding material of the invention was obtained.

(実施例2)
以下のようにして、図2に示した電磁波シールド材を製造した。
表面に格子状の凹凸を有する離型紙(100μm間隔で高低差約30μmの凹部と凸部が繰り返し形成されたもの)を用いた以外は、実施例1と同様にして、平均的な厚さ(a)=5μm 、銀含有率90.0質量%の電磁波シールド層を形成した。
次に、用いる銅粒子の粒径を変更し、樹脂液(S2)をコンマコータにてスリット100μmで塗布した以外は、実施例1と同様にして、樹脂層最小厚さ(bmin)=15μm、銅粒子の厚さ方向最大粒径(cmax)=30μm、銅含有率20質量%の導通層を形成した。
以上のようにして、電磁波シールド層と導通層との積層体を形成した後、これを離型紙から剥離した。
次に、接着剤液(S3)をコンマコータにてスリット70μmで塗布した以外は、実施例1と同様にして、最小厚さ(dmin)=0μm、最大厚さ(dmax)=20μmの接着剤層を有する離型紙付き接着剤層を得た。
実施例1と同様に、電磁波シールド層と導通層との積層体と、この離型紙付き接着剤層とをラミネートし、本発明の電磁波シールド材を得た。
(Example 2)
The electromagnetic wave shielding material shown in FIG. 2 was manufactured as follows.
The average thickness (as in Example 1), except that release paper having a lattice-like unevenness on the surface (repeatedly formed concave and convex portions having a height difference of about 30 μm at 100 μm intervals) was used. a) = 5 μm An electromagnetic wave shielding layer having a silver content of 90.0% by mass was formed.
Next, the resin layer minimum thickness (b min ) = 15 μm, except that the particle size of the copper particles used was changed and the resin liquid (S2) was applied with a comma coater at a slit of 100 μm, A conductive layer having a maximum particle size (c max ) in the thickness direction of copper particles of 30 μm and a copper content of 20% by mass was formed.
After forming the laminated body of the electromagnetic wave shielding layer and the conductive layer as described above, it was peeled from the release paper.
Next, adhesion with the minimum thickness (d min ) = 0 μm and the maximum thickness (d max ) = 20 μm was performed in the same manner as in Example 1 except that the adhesive liquid (S3) was applied with a slit of 70 μm with a comma coater. An adhesive layer with release paper having an adhesive layer was obtained.
In the same manner as in Example 1, the laminate of the electromagnetic wave shielding layer and the conductive layer and this adhesive layer with release paper were laminated to obtain the electromagnetic wave shielding material of the present invention.

(結果)
評価結果を表1に示す(厚さや粒径の単位はμm)。
電子顕微鏡観察を実施したところ、いずれの例においても、導通層を構成する少なくとも一部の銅粒子は、一端が電磁波シールド層に接触し、導通層を構成する樹脂層及び接着剤層を貫通して、他端が接着剤層より突出していることが確認された。また、いずれの例においても、低周波から高周波までの広域に渡って優れた電磁波シールド性を示し、さらには厚さ方向の抵抗値が小さく、厚さ方向に良好な導通性を有する電磁波シールド材が得られた。
(result)
The evaluation results are shown in Table 1 (the unit of thickness and particle size is μm).
When an electron microscope observation was performed, in any of the examples, at least some of the copper particles constituting the conductive layer had one end in contact with the electromagnetic wave shielding layer and penetrated the resin layer and the adhesive layer constituting the conductive layer. It was confirmed that the other end protruded from the adhesive layer. Moreover, in any example, an electromagnetic wave shielding material that exhibits excellent electromagnetic shielding properties over a wide range from low frequency to high frequency, and further has a small resistance value in the thickness direction and good conductivity in the thickness direction. was gotten.

Figure 0004673573
Figure 0004673573

本発明の電磁波シールド材は、ガスケット、壁紙、フレキシブルプリントサーキット、フラットフレキシブルケーブル等に貼着する電磁波シールドテープや電磁波シールドシート等として好ましく利用することができる。   The electromagnetic wave shielding material of the present invention can be preferably used as an electromagnetic wave shielding tape, an electromagnetic wave shielding sheet, or the like that is attached to a gasket, wallpaper, flexible printed circuit, flat flexible cable, or the like.

本発明に係る一実施形態の電磁波シールド材の構造を示す断面図である。It is sectional drawing which shows the structure of the electromagnetic wave shielding material of one Embodiment which concerns on this invention. 電磁波シールド材の他の態様を示す断面図である。It is sectional drawing which shows the other aspect of an electromagnetic wave shielding material.

符号の説明Explanation of symbols

1 電磁波シールド材
10 電磁波シールド層
11 樹脂層
12 導電粒子
20 導通層
21 樹脂層
22 導電粒子
30 接着剤層
40 離型シート

DESCRIPTION OF SYMBOLS 1 Electromagnetic shielding material 10 Electromagnetic shielding layer 11 Resin layer 12 Conductive particle 20 Conductive layer 21 Resin layer 22 Conductive particle 30 Adhesive layer 40 Release sheet

Claims (5)

電磁波シールド層の少なくとも片面に、少なくとも厚さ方向に対して導通性を有する導通層を具備し、前記電磁波シールド層は凹凸形状とされている電磁波シールド材の製造方法であって、
表面が凹凸形状とされた離型シート上に前記電磁波シールド層と前記導通層との積層体を形成する工程(A)と、前記離型シートを剥離する工程(B)とを順次有すると共に、
工程(A)は、前記離型シート上に導電粒子を含む樹脂液を塗布・固化し、前記電磁波シールド層を形成する工程(A1)と、該形成された電磁波シールド層上に導電粒子を含む樹脂液を塗布・固化し、前記導通層を形成する工程(A2)とを含むことを特徴とする電磁波シールド材の製造方法。
At least one surface of the electromagnetic wave shielding layer is provided with a conductive layer having conductivity at least in the thickness direction, and the electromagnetic wave shielding layer is a method for producing an electromagnetic wave shielding material having an uneven shape,
While sequentially having a step (A) of forming a laminate of the electromagnetic wave shielding layer and the conductive layer on a release sheet whose surface is uneven, and a step (B) of peeling the release sheet,
Step (A) includes applying and solidifying a resin liquid containing conductive particles on the release sheet to form the electromagnetic wave shielding layer (A1), and including the conductive particles on the formed electromagnetic wave shielding layer. And a step (A2) of applying and solidifying a resin liquid to form the conductive layer.
さらに、別の離型シート上に接着剤層を形成する工程(C)と、工程(A)で形成した前記積層体と前記接着剤層とを貼着する工程(D)とを有することを特徴とする請求項に記載の電磁波シールド材の製造方法。 Furthermore, it has a step (C) of forming an adhesive layer on another release sheet and a step (D) of adhering the laminate and the adhesive layer formed in step (A). method of manufacturing an electromagnetic wave shielding material according to claim 1, wherein. 前記導通層を構成する少なくとも一部の前記導電粒子の厚さ方向最大粒径(cmax)が、前記導通層を構成する樹脂層の最小厚さ(bmin)より大きく、その一端が前記電磁波シールド層に接触し、他端が前記樹脂層より突出していることを特徴とする請求項1又は2に記載の電磁波シールド材の製造方法The maximum particle size (c max ) in the thickness direction of at least a part of the conductive particles constituting the conductive layer is larger than the minimum thickness (b min ) of the resin layer constituting the conductive layer, and one end thereof is the electromagnetic wave. method of manufacturing an electromagnetic wave shielding material according to claim 1 or 2 in contact with the shield layer and the other end is characterized in that protrudes from the resin layer. 厚さ方向の抵抗値が0.5Ω以下であることを特徴とする請求項1〜3のいずれかに記載の電磁波シールド材の製造方法The resistance value in the thickness direction is 0.5Ω or less, The method for producing an electromagnetic wave shielding material according to any one of claims 1 to 3. 前記導通層を構成する少なくとも一部の前記導電粒子の厚さ方向最大粒径(cmax)が、前記導通層を構成する樹脂層の最小厚さ(bmin)と、前記接着剤層の最小厚さ(dmin)の合計より大きく、その一端が前記電磁波シールド層に接触し、他端が前記接着剤層より突出していることを特徴とする請求項2に記載の電磁波シールド材の製造方法The maximum particle size (c max ) in the thickness direction of at least a part of the conductive particles constituting the conductive layer is such that the minimum thickness (b min ) of the resin layer constituting the conductive layer and the minimum of the adhesive layer 3. The method for producing an electromagnetic shielding material according to claim 2, wherein one of the thicknesses (d min ) is larger, one end thereof is in contact with the electromagnetic shielding layer, and the other end protrudes from the adhesive layer. .
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